JP7619172B2 - Communication devices and equipment - Google Patents

Description

This disclosure relates to a communication device and a communication apparatus.

Patent Document 1 discloses a vehicle communication device that receives a differential signal represented by the voltage difference between two electrical signals propagating through two conductors. In this communication device, noise is removed from the two electrical signals using the potential of the first conductor as a reference potential. Furthermore, the differential signal represented by the voltage difference between the two electrical signals from which noise has been removed is converted into a voltage signal whose reference potential is the potential of the second conductor.

In the communication device, a voltage whose reference potential is the potential of the first conductor is applied via the connector. The applied voltage is converted to a voltage whose reference potential is the potential of the second conductor. The converted voltage is applied to a conversion unit that converts the differential signal into a voltage signal. This supplies power to the conversion unit.

JP 2020-167536 A

In the communication device described in Patent Document 1, the voltage needs to be converted in order to supply power to the conversion section. This requires a circuit element for converting the voltage. This results in a problem of high manufacturing costs.

This disclosure has been made in light of these circumstances, and its purpose is to provide an inexpensive communication device that does not require voltage conversion, and a communication device that includes this communication device.

A communication device according to one aspect of the present disclosure is attached to an in-vehicle device and receives a differential signal represented by the voltage difference between two electrical signals propagating through two conductors. The communication device includes a noise removal circuit that removes noise from the two electrical signals using the potential of the first conductor as a reference potential, a signal conversion unit that converts the differential signal represented by the voltage difference between the two electrical signals from which the noise removal circuit has removed noise into a voltage signal represented by a voltage whose reference potential is the potential of the second conductor, and a device connector that is connected to a power supply device that supplies power. The power supply device supplies power to the signal conversion unit by applying a voltage whose reference potential is the potential of the second conductor to the signal conversion unit via the device connector.

A communication device according to one aspect of the present disclosure includes a communicator that receives a differential signal represented by the voltage difference between two electrical signals propagating through two conductors, and a vehicle power supply device to which the communicator is attached and supplies power to the communicator. The communicator has a noise reduction circuit that removes noise from the two electrical signals using the potential of a first conductor as a reference potential, a signal conversion unit that converts the differential signal represented by the voltage difference between the two electrical signals from which the noise reduction circuit has removed noise into a voltage signal represented by a voltage whose reference potential is the potential of the second conductor, and a device connector that is connected to the power supply device. The power supply device has a power supply circuit that supplies power to the signal conversion unit by applying a voltage whose reference potential is the potential of the second conductor to the signal conversion unit via the device connector.

The above aspect realizes an inexpensive communication device that does not require voltage conversion.

1 is a block diagram showing a configuration of a main part of a communication system according to a first embodiment. FIG. 2 is a block diagram showing a main configuration of a repeater. FIG. 2 is a circuit diagram of a signal processing circuit. FIG. 2 is a perspective view of a relay device and a repeater. FIG. 2 is a cross-sectional view of a relay device and a repeater. FIG. 2 is an explanatory diagram of a connection between a relay device and a repeater. FIG. 2 is a front view of the repeater with the cover removed. 11A and 11B are explanatory diagrams of a method for inserting a sub-board. FIG. 11 is a perspective view of a relay device and a repeater in a second embodiment. FIG. 2 is a cross-sectional view of a relay device and a repeater. FIG. 2 is an explanatory diagram of a connection between a relay device and a repeater. FIG. 13 is a perspective view of a relay device and a repeater in a third embodiment. FIG. FIG. FIG. 2 is a cross-sectional view of a relay device and a repeater. FIG. 2 is an explanatory diagram of a connection between a relay device and a repeater. 13 is a cross-sectional view of a relay device and a repeater in a fourth embodiment. FIG. 5A and 5B are diagrams illustrating electrical continuity between a first main conductor and a first sub-conductor. FIG. 13 is a block diagram showing the main configuration of a communication system according to a fifth embodiment. FIG. 13 is a block diagram showing a configuration of a main part of a relay device according to a sixth embodiment. FIG. 2 is a block diagram showing a main configuration of a repeater. FIG. 2 is a plan view of a relay device and a repeater. FIG. 2 is an explanatory diagram of the external appearance of a repeater. FIG. FIG. FIG. 13 is a cross-sectional view of a repeater in embodiment 7. FIG. 23 is a front view of the repeater in the eighth embodiment. FIG. 13 is a side view of a repeater in embodiment 9. FIG. 23 is a block diagram showing the main configuration of a relay device according to a tenth embodiment. FIG. 11 is an explanatory diagram of the arrangement of a second conducting wire. FIG. 23 is a block diagram showing the main configuration of a relay device according to an eleventh embodiment. FIG. 13 is an explanatory diagram of the arrangement of connection parts. A block diagram showing the main configuration of a repeater in embodiment 12. FIG. 2 is a circuit diagram of a signal processing circuit. FIG. FIG. 23 is a block diagram showing the main configuration of a relay device according to a thirteenth embodiment. FIG. 11 is an explanatory diagram of an arrangement of second main conductors.

[Description of the embodiments of the present disclosure]
First, the embodiments of the present disclosure will be listed and described. At least a part of the embodiments described below may be arbitrarily combined.

(1) A communication device according to one aspect of the present disclosure is a communication device that is attached to an in-vehicle device and receives a differential signal represented by the voltage difference between two electrical signals propagating through two conductors, and includes a noise removal circuit that removes noise from the two electrical signals using the potential of a first conductor as a reference potential, a signal conversion unit that converts the differential signal represented by the voltage difference between the two electrical signals from which noise has been removed by the noise removal circuit into a voltage signal represented by a voltage whose reference potential is the potential of the second conductor, and a device connector that is connected to a power supply device that supplies power, and the power supply device supplies power to the signal conversion unit by applying a voltage whose reference potential is the potential of the second conductor to the signal conversion unit via the device connector.

In the above embodiment, the power supply applies a voltage whose reference potential is the potential of the second conductor to the signal conversion unit via the device connector. Therefore, there is no need to convert a voltage whose reference potential is the potential of the first conductor to a voltage whose reference potential is the potential of the second conductor. Because no circuit element for converting the voltage is required, manufacturing costs are low.

(2) In a communication device according to one aspect of the present disclosure, the differential signal is a communication signal conforming to the Ethernet (registered trademark) communication protocol, a communication signal using LVDS (Low Voltage Differential Signaling), or a communication signal conforming to USB (Universal Serial Bus).

In the above embodiment, a communication signal conforming to the Ethernet communication protocol, a communication signal using LVDS, or a communication signal conforming to USB is received.

(3) A communication device according to one aspect of the present disclosure includes a conductor connection element connected between the first conductor and the second conductor, the conductor connection element being an inductor, a resistor, or a conductor.

In the above embodiment, even if noise enters the first conductor and causes the potential of the first conductor to fluctuate, the reference potential has little effect on the voltage or electrical signal that is the potential of the second conductor. Similarly, even if noise enters the second conductor and causes the potential of the second conductor to fluctuate, the reference potential has little effect on the voltage or electrical signal that is the potential of the first conductor.

(4) A communication device according to one aspect of the present disclosure includes a substrate on which the first conductor and the second conductor are arranged, a box having an open surface and housing the substrate inserted from the open surface, and a rail disposed within the box and extending from the open surface toward a bottom surface of the box.

In the above embodiment, rails are provided inside the box. Therefore, the board can be easily stored inside the box by moving the board along the rails.

(5) A communication device according to one aspect of the present disclosure includes a substrate on which the first conductor and the second conductor are arranged, the device connector is arranged on an edge portion of one side of the substrate, and the first conductor and the second conductor are aligned along one side of the edge portion on which the device connector is arranged.

In the above embodiment, connection to a power supply can be achieved regardless of the size of the board.

(6) A communication device according to one aspect of the present disclosure includes a substrate on which the first conductor and the second conductor are arranged, the substrate having a circuit surface on which circuit elements are arranged, the device connector is arranged on the substrate and protrudes in a direction perpendicular to the circuit surface, and the power supply device is connected at the tip of the device connector.

In the above embodiment, connection to a power supply can be achieved regardless of the size of the board.

(7) A communication device according to one aspect of the present disclosure includes a substrate on which the first conductor and the second conductor are arranged, a conductive box that houses the substrate, and a protrusion that protrudes outward from the box and is used to fasten the box, the protrusion being conductive and electrically connected to the first conductor via the box.

In the above embodiment, the protrusion is connected to the power supply device board, for example, by soldering. This allows the protrusion to be electrically connected to a conductor arranged on the power supply device board. In this case, the first conductor is electrically connected to the conductor of the power supply device board via the box and the protrusion.

(8) In a communication device according to one aspect of the present disclosure, the protrusion has a through hole through which a conductive screw is passed, and the box is fixed by tightening the screw, and when the box is fixed, the screw is electrically conductive to the protrusion.

In the above embodiment, a screw is passed through the through hole of the protrusion. Then, for example, the screw is tightened on the power supply device board. As a result, the screw comes into contact with the conductive protrusion, and the box is fixed to the power supply device board. For example, the screw is conductive to a conductor within the power supply device board. In this case, the first conductor is conductive to the conductor of the power supply device board via the box, the protrusion, and the screw.

(9) A communication device according to one aspect of the present disclosure includes a second protrusion that is conductive, protrudes outward from the box body, and is used to fix the box body, the box body having a first conductive portion that is conductive and in electrical communication with the first conductor, a second conductive portion that is conductive and in electrical communication with the second conductor, and a connecting portion that is insulating and connects the first conductive portion and the second conductive portion, the protrusion protruding from the first conductive portion, and the second protrusion protruding from the second conductive portion.

In the above embodiment, the first conductive portion of the box is connected to the second conductive portion by an insulating connecting portion. The protrusion and the second protrusion can each be electrically connected to two conductors.

(10) A communication device according to one aspect of the present disclosure includes a substrate on which the first conductor and the second conductor are arranged, and a conductive box that houses the substrate, the substrate is provided with a second through hole through which a conductive second screw passes, the box is provided with a screw hole through which the second screw that has passed through the second through hole is inserted, and when the second screw is tightened in the screw hole, the first conductor is electrically connected to the box via the second screw.

In the above embodiment, the first conductor is electrically connected to the box body via the second screw.

(11) A communication device according to one aspect of the present disclosure includes a substrate on which the first conductor and the second conductor are arranged, the device connector has a conductive rod having electrical conductivity, and the substrate is provided with an insertion hole into which the conductive rod is inserted.

In the above embodiment, the conductive rod connects the power supply device and the signal conversion unit. The power supply device supplies power to the signal conversion unit via the conductive rod.

(12) A communication device according to one aspect of the present disclosure includes a communicator that receives a differential signal represented by the voltage difference between two electrical signals propagating through two conductors, and a vehicle power supply device to which the communicator is attached and that supplies power to the communicator. The communicator has a noise reduction circuit that removes noise from the two electrical signals using the potential of a first conductor as a reference potential, a signal conversion unit that converts the differential signal represented by the voltage difference between the two electrical signals from which the noise has been removed by the noise reduction circuit into a voltage signal represented by a voltage whose reference potential is the potential of the second conductor, and a device connector that is connected to the power supply device. The power supply device has a power supply circuit that supplies power to the signal conversion unit by applying a voltage whose reference potential is the potential of the second conductor to the signal conversion unit via the device connector.

In the above embodiment, the power supply circuit of the power supply device applies a voltage whose reference potential is the potential of the second conductor to the signal conversion section of the communication device via the device connector. Therefore, the communication device does not need to convert a voltage whose reference potential is the potential of the first conductor to a voltage whose reference potential is the potential of the second conductor. Because no circuit element for converting the voltage is required, the manufacturing cost of the communication device is low.

(13) In a communication device according to one aspect of the present disclosure, the power supply device has a power supply conductor, the power supply circuit of the power supply device applies a voltage whose reference potential is the potential of the power supply conductor to the signal conversion unit via the device connector, and the second conductor is connected to the power supply conductor via the device connector.

In the above embodiment, the second conductor of the communication device is connected to the power supply conductor of the power supply device via the device connector. Therefore, the potential of the second conductor is the same as the potential of the power supply conductor.

(14) In a communication device according to one aspect of the present disclosure, the power supply device has a second power supply conductor and a voltage conversion unit that converts a voltage whose reference potential is the potential of the second power supply conductor into a voltage whose reference potential is the potential of the power supply conductor, and the first conductor is connected to the second power supply conductor via the device connector.

In the above embodiment, the first conductor of the communication device is connected to the second power conductor of the power supply device via the device connector. The second conductor of the communication device is connected to the power conductor of the power supply device via the device connector. The voltage conversion unit of the power supply device converts a voltage whose reference potential is the potential of the second power conductor into a voltage whose reference potential is the potential of the power conductor. The power supply circuit of the power supply device applies a voltage whose reference potential is the potential of the power conductor to the signal conversion unit of the communication device via the device connector.

(15) In a communication device according to one aspect of the present disclosure, the power supply device has a power conductor and a second power conductor, the power conductor and the second power conductor are connected to the second conductor and the first conductor, respectively, and the power conductor and the second power conductor are connected by an inductor, a resistor, or a second conductor.

In the above embodiment, the second conductor has a resistance component. The power supply conductor and the second power supply conductor are connected by an inductor, a resistor, or a second conductor. Therefore, even if noise enters the power supply conductor and the potential of the power supply conductor fluctuates, the reference potential has little effect on the voltage or electrical signal, which is the potential of the second power supply conductor. Similarly, even if noise enters the second power supply conductor and the potential of the second power supply conductor fluctuates, the reference potential has little effect on the voltage or electrical signal, which is the potential of the power supply conductor.

(16) In a communication device according to one aspect of the present disclosure, the communicator transmits data contained in the voltage signal converted by the signal conversion unit to the power supply device via the device connector.

In the above embodiment, the power supply device receives data from the communication device.

[Details of the embodiment of the present disclosure]
Specific examples of communication systems according to embodiments of the present disclosure will be described below with reference to the drawings. Note that the present invention is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims.

(Embodiment 1)
<Configuration of communication system>
Fig. 1 is a block diagram showing a main configuration of a communication system 1 in the first embodiment. The communication system 1 is mounted on a vehicle M. The communication system 1 includes a relay device 10, a repeater 11, a DC power supply 12, and a plurality of ECUs (Electronic Control Units) 13 and 14. The relay device 10 is, for example, an ECU. The repeater 11 includes, for example, an integrated circuit element. The DC power supply 12 is, for example, a battery. The relay device 10 has a power supply connector 20, two bus connectors 21, and an equipment connector 22. In Fig. 1, signal lines through which signals propagate are indicated by thick lines. Wiring different from the signal lines is indicated by thin lines.

The positive and negative poles of the DC power supply 12 are each connected to the power supply connection body 20 of the relay device 10. The negative pole of the DC power supply 12 is further grounded. The grounding is achieved, for example, by connecting it to the body of the vehicle M. A communication bus Lb is connected to each of the two bus connection bodies 21 of the relay device 10. A plurality of ECUs 13 are connected to each of the communication buses Lb. A repeater 11 is connected to the equipment connection body 22 of the relay device 10. The repeater 11 is connected to each of the plurality of ECUs 14 by a communication line Lc.

The repeater 11 is attached to the device connection body 22 of the repeater 10. This connects the repeater 11 to the device connection body 22. The DC power supply 12 supplies power to the repeater 10. The repeater 10 supplies power to the repeater 11. The repeater 10 functions as a power supply device and an in-vehicle device. The repeater 10 and the repeater 11 each perform various processes using the supplied power. The repeater 10 and the ECU 13 each transmit a differential signal including data via the communication bus Lb. The transmission of the differential signal corresponds to the transmission of data. The communication bus Lb includes two conductors. The differential signal is represented by the voltage difference between two electrical signals propagating through each of the two conductors. The differential signal transmitted via the communication bus Lb is received by all devices connected to the communication bus Lb.

Each of the ECUs 13 and 14 is connected to an actuator and a sensor (not shown). Each of the ECUs 13 and 14 acquires the detection results detected by the sensor. Each of the ECUs 13 and 14 outputs an operation signal to the actuator. The operation signal indicates the operation of the actuator. When an operation signal is input, the actuator executes the operation indicated by the input operation signal. Each of the ECUs 13 and 14 controls the operation of the actuator by outputting an operation signal to the actuator. The actuator is a door motor that locks and unlocks the door, a wiper motor that swings the wipers, a lamp, etc.

When ECU 13 receives a differential signal via communication bus Lb, it determines whether the destination of the data included in the received differential signal is its own device. When ECU 13 determines that the destination of the data is its own device, it controls the operation of the actuator based on the data of the received differential signal. ECU 13 transmits, for example, a differential signal including data indicating the detection result detected by a sensor via communication bus Lb. The destination of the data included in the differential signal is ECU 13 or ECU 14, which is different from the source.

When the relay device 10 receives a differential signal via the communication bus Lb, it determines whether or not to relay the transmission of the data based on the destination of the data contained in the received differential signal. When the relay device 10 determines to relay the transmission of the data, it performs at least one of two processes. The first process is the transmission of the differential signal via a communication bus Lb different from the communication bus Lb used to receive the differential signal. The second process is the transmission of a voltage signal including the data to the relay 11. The voltage signal is a signal represented by a voltage whose reference potential is the potential of the conductor. The transmission of a voltage signal also corresponds to the transmission of data.

When the repeater 11 receives a voltage signal from the relay device 10, it generates a differential signal including data of the received voltage signal. The repeater 11 transmits the generated differential signal to the ECU 14 via the communication line Lc. The communication line Lc includes two conductors Wa, Wb (see FIG. 3) similar to the communication bus Lb. The differential signal is represented by the voltage difference between the two electrical signals propagating through each of the two conductors Wa, Wb.

The ECU 14 transmits, for example, a differential signal including data indicating the detection result detected by the sensor to the repeater 11 via the communication line Lc. The destination of the data included in the differential signal is the ECU 13 or an ECU 14 different from the sender. The repeater 11 receives the differential signal. The repeater 11 functions as a communication device. An apparatus including the relay device 10 and the repeater 11 functions as a communication device.

When the repeater 11 receives a differential signal from the ECU 14, if the destination of the data contained in the received differential signal is an ECU 14 different from the source, the repeater 11 transmits the differential signal including the data to the destination ECU 14.

When the ECU 14 receives a differential signal via the communication line Lc, it controls the actuator based on the data contained in the received differential signal.

When the repeater 11 receives a differential signal from the ECU 14, and the destination of the data contained in the received differential signal is the ECU 13, the repeater 11 transmits a voltage signal including the data of the received differential signal to the repeater device 10. When the repeater device 10 receives a voltage signal from the repeater 11, the repeater device 10 transmits a differential signal including the data of the received voltage signal to the ECU 13 via the communication bus Lb.

As described above, the relay device 10 relays data communication between two ECUs 13 connected to two mutually different communication buses Lb. The relay 11 relays data communication between two ECUs 14. The relay device 10 and the relay 11 relay communication between the ECUs 13 and 14.

Communication via the communication bus Lb is performed, for example, according to a CAN (Controller Area Network) communication protocol. Communication via the communication line Lc is performed, for example, according to an Ethernet (registered trademark) communication protocol.

<Configuration of relay device 10>
The relay device 10 includes a power connector 20, two bus connectors 21, and an equipment connector 22, as well as a common mode choke coil 23, a power circuit 24, a communication circuit 25, a first main conductor Gm1, and a second main conductor Gm2. The common mode choke coil 23 includes a first inductor 23a, a second inductor 23b, and a ring-shaped magnetic body (not shown). The first inductor 23a and the second inductor 23b are wound around the magnetic body. The potentials of the first main conductor Gm1 and the second main conductor Gm2 function as grounds. The first main conductor Gm1 functions as a second power conductor. The second main conductor Gm2 functions as a power conductor.

One end of the first inductor 23a and one end of the second inductor 23b are each connected to the power supply connector 20. A connection node between the second inductor 23b and the power supply connector 20 is connected to the first main conductor Gm1. The other end of the first inductor 23a is connected to the power supply circuit 24. The other end of the second inductor 23b and the power supply circuit 24 are each connected to the second main conductor Gm2.
As described above, the second inductor 23b connects the first main conductor Gm1 and the second main conductor Gm2. The circuit element connecting the first main conductor Gm1 and the second main conductor Gm2 is not limited to the second inductor 23b and may be, for example, a resistor. In this case, the power supply connector 20 is connected to the power supply circuit 24 without passing through the first inductor 23a.

The power supply circuit 24 is further connected to the repeater 11 and the communication circuit 25. The communication circuit 25 is further connected to the two bus connectors 21, the device connector 22, the first main conductor Gm1, and the second main conductor Gm2, respectively. The first main conductor Gm1 and the second main conductor Gm2 are each connected to the device connector 22.

A voltage whose reference potential is the potential of the first main conductor Gm1 is applied from the DC power supply 12 to one end of the first inductor 23a and the second inductor 23b of the common mode choke coil 23. The common mode choke coil 23 removes common mode noise from the applied voltage. Common mode noise is noise that is superimposed in phase on the two conductors connected to one end of the first inductor 23a and the second inductor 23b.

The common mode choke coil 23 applies a voltage from which common mode noise has been removed to the power supply circuit 24 from the other end of the first inductor 23a. As described above, the other end of the second inductor 23b and the power supply circuit 24 are connected to the second main conductor Gm2. Therefore, the voltage that the common mode choke coil 23 applies to the power supply circuit 24 is a voltage whose reference potential is the potential of the second main conductor Gm2.

As described above, the common mode choke coil 23 converts a voltage whose reference potential is the potential of the first main conductor Gm1 into a voltage whose reference potential is the potential of the second main conductor Gm2. The common mode choke coil 23 functions as a voltage conversion unit.

The power supply circuit 24 steps down the voltage applied from the common mode choke coil 23 to a constant voltage such as 5V or 3.3V. The power supply circuit 24 applies the constant voltage generated by stepping down the voltage to the repeater 11 via the device connector 22. The power supply circuit 24 further applies the constant voltage generated to the communication circuit 25. This supplies power to the repeater 11 and the communication circuit 25. The reference potential of the constant voltage is the potential of the second main conductor Gm2.

When the communication circuit 25 receives a differential signal via the communication bus Lb, it removes noise from the two electrical signals that make up the received differential signal, using the potential of the first main conductor Gm1 as a reference potential. The communication circuit 25 converts the differential signal, which is represented by the voltage difference between the two electrical signals from which noise has been removed, into a voltage signal whose reference potential is the potential of the second main conductor Gm2. The communication circuit 25 acquires the data contained in the converted voltage signal.

The communication circuit 25 determines whether or not to relay the transmission of the data based on the destination of the acquired data. If the communication circuit 25 determines to relay the transmission of the data, it performs at least one of the two processes described above. The first process described above is the transmission of a differential signal via a communication bus Lb different from the communication bus Lb used to receive the differential signal. The second process is the transmission of a voltage signal including the data to the repeater 11.

In the first process, the communication circuit 25 generates a differential signal including the acquired data and transmits the generated differential signal via a communication bus Lb different from the communication bus Lb used to receive the differential signal. In the second process, the communication circuit 25 transmits a voltage signal including the acquired data to the repeater 11. As described above, when the repeater 11 receives a voltage signal from the communication circuit 25, it generates a differential signal including data of the received voltage signal. The repeater 11 transmits the generated differential signal to the ECU 14.

As described above, the communication circuit 25 processes electrical signals with the potential of the first main conductor Gm1 as the reference potential, and processes electrical signals with the potential of the second main conductor Gm2 as the reference potential.

As described above, the relay device 10 has a first main conductor Gm1 and a second main conductor Gm2. Therefore, even if noise enters the first main conductor Gm1 and the potential of the first main conductor Gm1 fluctuates, the reference potential has little effect on the voltage or electrical signal which is the potential of the second main conductor Gm2. Similarly, even if noise enters the second main conductor Gm2 and the potential of the second main conductor Gm2 fluctuates, the reference potential has little effect on the voltage or signal which is the potential of the first main conductor Gm1.

The number of ECUs 13 connected to one communication bus Lb may be one. Furthermore, the number of communication buses Lb connected to the relay device 10 is not limited to two, and may be one or three or more. The number of bus connectors 21 possessed by the relay device 10 is adjusted to the same number as the number of communication buses Lb. When the number of communication buses Lb is one, the relay device 10 does not relay communication between two ECUs 13.

<Configuration of repeater 11>
Fig. 2 is a block diagram showing the main configuration of the repeater 11. Fig. 2 shows an example in which the number of ECUs 14 is three. There is no problem with the number of ECUs 14 connected to the repeater 11 as long as it is one or more. Therefore, the number of ECUs 14 is not limited to three. In Fig. 2 as well, signal lines are indicated by thick lines as in Fig. 1. Wiring other than the signal lines is indicated by thin lines.

As shown in FIG. 2, the repeater 11 has a communication line connector 30, three signal processing circuits 31, three signal conversion units 32, a relay unit 33, a device connector 34, a first sub-conductor Gs1, and a second sub-conductor Gs2. One end of each of the three communication lines Lc is connected to the communication line connector 30. As described above, the communication line Lc includes two conductors Wa and Wb. The other end of the communication line Lc is connected to the ECU 14. The device connector 34 is connected to the device connector 22 of the repeater 10. The potentials of the first sub-conductor Gs1 and the second sub-conductor Gs2 function as ground.

The communication line connector 30 is connected to three signal processing circuits 31, respectively. The three signal processing circuits 31 are connected to three signal conversion units 32, respectively. The three signal conversion units 32 are further connected to the relay unit 33, respectively. The three signal conversion units 32 and the relay unit 33 are further connected to the device connector 34, respectively. The device connector 34 is further connected to the first sub-conductor Gs1 and the second sub-conductor Gs2, respectively. The three signal processing circuits 31 are connected to the first sub-conductor Gs1 and the second sub-conductor Gs2, respectively. The three signal conversion units 32 and the relay unit 33 are further connected to the second sub-conductor Gs2, respectively.

As described above, the relay device 10 has a power circuit 24, a communication circuit 25, a first main conductor Gm1, and a second main conductor Gm2. The device connection body 34 of the relay device 11 is connected to the device connection body 22 of the relay device 10. The communication circuit 25 is connected to the relay section 33 via the device connection body 22 and the device connection body 34. The power circuit 24 is connected to the three signal conversion sections 32 and the relay section 33 via the device connection body 22 and the device connection body 34. The first main conductor Gm1 is connected to the first sub-conductor Gs1 via the device connection body 22 and the device connection body 34. The second main conductor Gm2 is connected to the second sub-conductor Gs2 via the device connection body 22 and the device connection body 34.

The number of signal processing circuits 31 and signal conversion units 32 is the same as the number of ECUs 14. Therefore, if the number of ECUs 14 is different from three, the number of signal processing circuits 31 and signal conversion units 32 is adjusted to the same as the number of ECUs 14.

As described above, the power supply circuit 24 applies a constant voltage whose reference potential is the potential of the second main conductor Gm2 to the relay 11. The second main conductor Gm2 is connected to the second sub-conductor Gs2. Therefore, the potential of the second main conductor Gm2 is the same as the potential of the second sub-conductor Gs2. The power supply circuit 24 applies a constant voltage whose reference potential is the potential of the second sub-conductor Gs2 to the signal conversion unit 32 and the relay unit 33 via the device connector 34. This supplies power to the signal conversion unit 32 and the relay unit 33.

As described above, the ECU 14 transmits a differential signal via the communication line Lc. In the repeater 11, the differential signal is input to the signal processing circuit 31 via the communication line Lc and the communication line connector 30. The signal processing circuit 31 removes noise from the two electrical signals that constitute the differential signal input via the communication line Lc and the communication line connector 30, using the potential of the first sub-conductor Gs1 as a reference potential. Here, the noise to be removed is, for example, electrostatic noise that is superimposed on a signal when static electricity is generated. When electrostatic noise is superimposed on an electrical signal, the voltage of the electrical signal temporarily rises significantly. The first sub-conductor Gs1 functions as a first conductor. The signal processing circuit 31 functions as a noise removal circuit.

The signal processing circuit 31 removes common mode noise from a differential signal composed of two electrical signals from which noise has been removed. Common mode noise is noise that is superimposed in phase on the two conductors that make up the communication line Lc. The signal processing circuit 31 removes noise from the two electrical signals that make up the differential signal from which common mode noise has been removed, using the potential of the second sub-conductor Gs2 as a reference potential. The noise that is removed here is, for example, static electricity noise.

The signal processing circuit 31 outputs a differential signal represented by the voltage difference between the two electrical signals from which noise has been removed to the signal conversion unit 32. As a result, the signal conversion unit 32 receives the differential signal. The signal conversion unit 32 converts the received differential signal into a voltage signal represented by a voltage whose reference potential is the potential of the second sub-conductor Gs2. The second sub-conductor Gs2 functions as a second conductor. The signal conversion unit 32 outputs the converted voltage signal to the relay unit 33. The relay unit 33 acquires the data contained in the input voltage signal.

When the destination of the acquired data is the ECU 13, the relay unit 33 generates a voltage signal including the acquired data. Here, the reference potential of the voltage signal is the potential of the second sub-conductor Gs2 (second main conductor Gm2). The relay unit 33 transmits the generated voltage signal to the communication circuit 25 via the device connector 34 and the equipment connector 22. As a result, the communication circuit 25 receives the data from the relay unit 33.

When the destination of the acquired data is ECU 14, relay unit 33 generates a voltage signal including the acquired data. Again, the reference potential of the voltage signal is the potential of second sub-conductor Gs2. Relay unit 33 outputs the generated voltage signal to signal conversion unit 32.

The communication circuit 25 transmits a voltage signal whose reference potential is the potential of the second main conductor Gm2 (second sub-conductor Gs2) to the relay unit 33. When the relay unit 33 receives a voltage signal, it acquires data of the received voltage signal. The relay unit 33 generates a voltage signal including the acquired data, and outputs the generated voltage signal to the signal conversion unit 32.

When a voltage signal is input from the relay unit 33, the signal conversion unit 32 converts the input voltage signal into a differential signal. The signal conversion unit 32 transmits the converted differential signal to the ECU 14 via the signal processing circuit 31 and the communication line connector 30.

As described above, the power supply circuit 24 of the relay device 10 applies a constant voltage whose reference potential is the potential of the second sub-conductor Gs2 to the signal conversion section 32 and relay section 33 of the repeater 11 via the device connector 34. Therefore, within the repeater 11, there is no need to convert a voltage whose reference potential is the first sub-conductor Gs1 to a voltage whose reference potential is the second sub-conductor Gs2. Because no circuit element for converting the voltage is required, the manufacturing cost of the repeater 11 is low.

The differential signal transmitted via the communication line Lc is a communication signal conforming to the Ethernet (registered trademark) communication protocol, a communication signal using LVDS (Low Voltage Differential Signaling), or a communication signal conforming to USB (Universal Serial Bus).

In communications conforming to the Ethernet communication protocol, communications using LVDS, or communications conforming to USB, signals are sent and received in a P2P (peer-to-peer) format. This allows for a large amount of data to be sent per unit time. When the P2P (peer-to-peer) format is used, it is difficult to increase the number of ECUs 14 when ECUs 14 are directly connected to the relay device. However, repeaters 11 are connected to the relay device 10. This allows for the number of ECUs 14 to be easily increased or decreased by replacing the current repeaters 11 with other repeaters 11.

An example of communication in which differential signals are transmitted is communication that complies with the CAN (Controller Area Network) communication protocol. In this type of communication, ECUs are connected to a communication bus. This makes it easy to add or remove ECUs. However, since it is not a P2P format, the amount of data that can be transmitted per unit time is small.

When ECUs 14 are directly connected to relay devices, it is difficult to increase or decrease the number of ECUs 14 after the relay devices are manufactured. Assume that a new sensor is installed in the vehicle after the relay devices are manufactured. In this case, it may become necessary to transmit the detection results detected by the sensor from one ECU 14 to ECU 13 or another ECU 14. In this case, it is necessary to increase the number of ECUs 14 connected to the relay devices. However, since ECUs 14 are directly connected to the relay devices, it is necessary to manufacture new relay devices.

However, in the communication system 1, an ECU 14 that transmits sensor detection values can be easily added by replacing the current repeater 11 with another repeater 11. Also, the repeater 11 can be replaced. Therefore, depending on the situation of the vehicle M, a repeater 11 can be attached to each of multiple relay devices 10 with mutually different functions.

<Configuration of signal processing circuit 31>
3 is a circuit diagram of the signal processing circuit 31. The signal processing circuit 31 includes two first suppressors 40a and 40b, three resistors 41a, 41b, and 42, three capacitors 43, 44a, and 44b, a common mode choke coil 45, and two second suppressors 46a and 46b. The common mode choke coil 45 includes a first inductor 45a, a second inductor 45b, and an annular magnetic body. Each of the first inductor 45a and the second inductor 45b is wound around the magnetic body.

As described above, the communication line Lc includes two conductors Wa and Wb. A capacitor 44a and a first inductor 45a of the common mode choke coil 45 are arranged in the middle of the conductor Wa. The capacitor 44a is arranged on the communication line connector 30 side of the first inductor 45a. Similarly, a capacitor 44b and a second inductor 45b of the common mode choke coil 45 are arranged in the middle of the conductor Wb. The capacitor 44b is arranged on the communication line connector 30 side of the second inductor 45b.

On the communication line connector 30 side of the capacitor 44a, one end of the first suppressor 40a and one end of the resistor 41a are connected to the conductor Wa. The connection point of the first suppressor 40a is located closer to the communication line connector 30 than the connection point of the resistor 41a. Similarly, on the communication line connector 30 side of the capacitor 44b, one end of the first suppressor 40b and one end of the resistor 41b are connected to the conductor Wb. The connection point of the first suppressor 40b is located closer to the communication line connector 30 than the connection point of the resistor 41b.

The other end of resistor 41a is connected to the other end of resistor 41b. The connection node between resistors 41a and 41b is connected to one end of resistor 42 and capacitor 43. The other ends of the first suppressors 40a and 40b, resistor 42, and capacitor 43 are connected to the first sub-conductor Gs1.

On the signal conversion unit 32 side of the first inductor 45a, one end of the second suppressor 46a is connected to the conductor Wa. Similarly, on the signal conversion unit 32 side of the second inductor 45b, one end of the second suppressor 46b is connected to the conductor Wb. The other ends of the second suppressors 46a and 46b are connected to the second sub-conductor Gs2.

Each of the first suppressors 40a, 40b includes a suppressor, a varistor, a capacitor, or the like. Each of the first suppressors 40a, 40b suppresses the peak values of two electrical signals whose reference potential is the potential of the first sub-conductor Gs1. As described above, the peak value of the electrical signal may temporarily increase significantly due to noise superposition. Electrostatic noise is removed from the electrical signal by suppressing the peak value. Each of the two electrical signals propagates through two conductors Wa, Wb. Each of the first suppressors 40a, 40b suppresses the peak values of the two electrical signals that constitute the differential signal input from the communication line connector 30.

The resistors 41 a , 41 b , and 42 and the capacitor 43 function as a termination circuit, and suppress reflection of the differential signal input from the communication line connector 30 side.
Each of the capacitors 44a and 44b removes the DC component of two electrical signals constituting the differential signal input from the communication line connector 30. The capacitors 44a and 44b output a differential signal represented by the voltage difference between the two electrical signals from which the DC components have been removed to the common mode choke coil 45.

The common mode choke coil 45 removes common mode noise from the differential signal output by the capacitors 44a and 44b, and outputs the differential signal from which the common mode noise has been removed to the signal conversion unit 32.

Each of the second suppressors 46a and 46b includes a suppressor, a varistor, a capacitor, a Zener diode, a diode clamp circuit, or the like. Each of the second suppressors 46a and 46b suppresses the peak values of two electric signals whose reference potential is the potential of the second sub-conductor Gs2. This removes noise from the two electric signals. The noise to be removed is, for example, electrostatic noise. Each of the two electric signals propagates through the two conductors Wa and Wb. Each of the second suppressors 46a and 46b suppresses the peak values of two electric signals constituting the differential signal input from the common mode choke coil 45. The differential signal constituted by the two electric signals whose peak values have been suppressed is input to the signal conversion unit 32.

As described above, the signal conversion unit 32 transmits a differential signal via the communication line Lc. In this case, each of the second suppressors 46a and 46b suppresses the peak values of the two electrical signals constituting the differential signal input from the signal conversion unit 32. This removes noise from the two electrical signals. The differential signal composed of the two electrical signals with suppressed peak values is input to the common mode choke coil 45. The common mode choke coil 45 removes common mode noise from the differential signal input from the signal conversion unit 32 side, and outputs the differential signal from which the common mode noise has been removed to the communication line connector 30 side.

Each of the capacitors 44a, 44b removes the DC component of the two electrical signals constituting the differential signal input from the signal conversion unit 32 side. The capacitors 44a, 44b output a differential signal represented by the voltage difference between the two electrical signals from which the DC component has been removed to the communication line connection body 30 side. Each of the first suppressors 40a, 40b suppresses the peak values of the two electrical signals constituting the differential signal output by the capacitors 44a, 44b. This removes noise from the two electrical signals. The differential signal composed of the two electrical signals with the suppressed peak values is output to the ECU 14 via the communication line connection body 30.

As described above, the signal processing circuit 31 removes noise from the two electrical signals using the potential of the first sub-conductor Gs1 as a reference potential. The signal processing circuit 31 removes noise from the two electrical signals using the potential of the second sub-conductor Gs2 as a reference potential.

As described above, the repeater 11 has the first sub-conductor Gs1 and the second sub-conductor Gs2. Therefore, even if the potential of the first sub-conductor Gs1 fluctuates due to noise entering the first sub-conductor Gs1, the reference potential has little effect on the voltage or signal which is the potential of the second sub-conductor Gs2. Similarly, even if the potential of the second sub-conductor Gs2 fluctuates due to noise entering the second sub-conductor Gs2, the reference potential has little effect on the voltage or signal which is the potential of the first sub-conductor Gs1. The noise input to the first sub-conductor Gs1 is output to the outside of the repeater 10 via the first main conductor Gm1 and the power supply connector 20.
The signal processing circuit 31 may be configured without the two second suppressors 46a, 46b.

<External appearance and internal structure of relay device 10 and repeater 11>
Fig. 4 is a perspective view of the relay device 10 and the repeater 11. Fig. 5 is a cross-sectional view of the relay device 10 and the repeater 11. Figs. 4 and 5 show an example in which the number of bus connectors 21 is two. As shown in Fig. 5, the relay device 10 further has an equipment box 26. The repeater 11 further has an equipment box 35. The equipment box 26 and the equipment box 35 are integrally formed. The equipment box 26 and the equipment box 35 constitute a housing box H.

The storage box H is a hollow rectangular parallelepiped. The space inside the storage box H is divided into two spaces by a partition plate extending in the vertical direction. The upper and lower sides of FIG. 4 correspond to the upper and lower sides of the relay device 10 and the repeater 11, respectively. As shown in FIGS. 4 and 5, the equipment box 35 also has a hollow rectangular parallelepiped shape. The left wall of the equipment box 35 is part of the partition plate and protrudes rearward from the front wall of the storage box H. The rear wall of the equipment box 35 is part of the partition plate and protrudes leftward from the right wall of the storage box H. The left wall of the equipment box 35 is connected to the rear wall. The left wall and rear wall of the equipment box 35 are part of the device box 26.

Note that with respect to the relay device 10 and the repeater 11, the front side and the rear side correspond to the left side and the right side, respectively, of FIG. 5. Similarly, with respect to the relay device 10 and the repeater 11, the right side and the left side correspond to the upper side and the lower side, respectively, of FIG. 5.

As shown in Figs. 4 and 5, the front wall of the device box 26 is provided with an opening 26a and multiple openings 26b that penetrate in the front-rear direction. Each of the openings 26a and 26b is rectangular. The power connector 20 of the relay device 10 is rectangular and is fitted into the opening 26a. The front surface of the power connector 20 is provided with a recess that is recessed toward the rear. For example, the end of a cable including two conductors connected to the positive and negative electrodes of the DC power supply 12 is inserted into the recess of the power connector 20. As a result, the positive and negative electrodes of the DC power supply 12 are each connected separately to the common mode choke coil 23.

The bus connector 21 of the relay device 10 has a rectangular parallelepiped shape and is fitted into the opening 26b. The front surface of the bus connector 21 is provided with a recess that is recessed toward the rear side. For example, an end of the communication bus Lb is inserted into the recess of the bus connector 21. In this way, the communication bus Lb is connected to the communication circuit 25.

The front wall of the equipment box 35 is provided with a rectangular opening 35a that penetrates in the front-rear direction. Therefore, the equipment box 35 has an open surface. The opening 35a is closed by a lid 36 that is a rectangular plate. The main surface of the lid 36 is aligned with the front surface of the storage box H. With respect to the plate, the main surface is the wide surface and is different from the end surface. The lid 36 is provided with a rectangular opening 36a that penetrates in the front-rear direction. The communication line connector 30 is rectangular and is fitted into the opening 36a. The front surface of the communication line connector 30 is provided with a recess that is recessed toward the rear. For example, the end of a cable including multiple communication lines Lc is inserted into the recess of the communication line connector 30. This connects the communication bus Lb to the signal processing circuit 31.

The relay device 10 has a main board Bm. FIG. 5 shows a plan view of the main board Bm. As shown in FIG. 5, the main board Bm is housed in the device box 26. When the main board Bm is viewed from above, it is L-shaped. A first main conductor Gm1 and a second main conductor Gm2 are arranged inside the main board Bm. Each of the first main conductor Gm1 and the second main conductor Gm2 is plate-shaped. The first main conductor Gm1 is separated from the second main conductor Gm2. The upper and lower surfaces of the main board Bm, the first main conductor Gm1, and the second main conductor Gm2 are the main surfaces.

On the top surface of the main board Bm, a power supply connector 20, multiple bus connectors 21, equipment connectors 22, a common mode choke coil 23, a power supply circuit 24, and a communication circuit 25 are arranged. The power supply connector 20 and multiple bus connectors 21 are arranged near the front wall of the device box 26. The equipment connector 22 is arranged near the rear wall of the equipment box 35. The equipment connector 22 has a rectangular parallelepiped shape. The front surface of the equipment connector 22 faces the rear surface of the equipment box 35. The arrangement of the power supply circuit 24 refers to the arrangement of one or more circuit elements that constitute the power supply circuit 24. The arrangement of the communication circuit 25 refers to the arrangement of one or more circuit elements that constitute the communication circuit 25.

The first main conductor Gm1 is disposed below the power connector 20 and the bus connector 21. The power connector 20 and the bus connector 21 are connected to the first main conductor Gm1 by through holes, conductive patterns, etc. (not shown). The first main conductor Gm1 and the second main conductor Gm2 are disposed below the device connector 22, the common mode choke coil 23, and the communication circuit 25. As described above, the device connector 22, the common mode choke coil 23, and the communication circuit 25 are connected to the first main conductor Gm1 and the second main conductor Gm2 by through holes, conductive patterns, etc. The second main conductor Gm2 is disposed below the power circuit 24. As described above, the power circuit 24 is connected to the second main conductor Gm2 by through holes, conductive patterns, etc.

The repeater 11 has a rectangular sub-substrate Bs. FIG. 5 shows a plan view of the sub-substrate Bs. As shown in FIG. 5, the sub-substrate Bs is housed in an equipment case 35. A first sub-conductor Gs1 and a second sub-conductor Gs2 are arranged inside the sub-substrate Bs. The first sub-conductor Gs1 is separated from the second sub-conductor Gs2. The upper and lower surfaces of the sub-substrate Bs, the first sub-conductor Gs1, and the second sub-conductor Gs2 are the main surfaces.

A communication line connector 30, a plurality of signal processing circuits 31, a plurality of signal conversion sections 32, a relay section 33, and an equipment connector 34 are arranged on the upper surface of the sub-substrate Bs. The communication line connector 30 is arranged near the front wall of the equipment box 35. The equipment connector 34 is arranged near the rear wall of the equipment box 35, and is located in front of the equipment connector 22 of the relay device 10. The common mode choke coil 45 of the signal processing circuit 31 is arranged in the center of the upper surface of the sub-substrate Bs.

The arrangement of the signal processing circuit 31 refers to the arrangement of one or more circuit elements that make up the signal processing circuit 31. The arrangement of the signal conversion unit 32 refers to the arrangement of one or more circuit elements that make up the signal conversion unit 32. The arrangement of the relay unit 33 refers to the arrangement of one or more circuit elements that make up the relay unit 33.

In FIG. 5, the circuit elements other than the common mode choke coil 23 are omitted from the signal processing circuit 31. The signal conversion units 32 and relay units 33 are also omitted. FIG. 5 shows an example in which the number of signal processing circuits 31 and the number of signal conversion units 32 are three. The following drawings also show examples in which the number of signal processing circuits 31 and the number of signal conversion units 32 are three.

As shown in FIG. 5, an opening 35b is provided in the rear wall of the equipment box 35, penetrating in the front-rear direction. The equipment connector 34 has a rectangular parallelepiped shape. The equipment connector 34 is fitted into the opening 35b. The rear surface of the equipment connector 34 faces the front surface of the equipment connector 22 of the relay device 10.

A first sub-conductor Gs1 is disposed below the communication line connector 30. The communication line connector 30 is connected to the first sub-conductor Gs1 by a through hole, a conductive pattern, or the like. A first sub-conductor Gs1 and a second sub-conductor Gs2 are disposed below the device connector 34 and the common mode choke coil 45, respectively. The device connector 34 is connected to the first sub-conductor Gs1 and the second sub-conductor Gs2 by a through hole, a conductive pattern, or the like.

As described above, the signal processing circuit 31 is connected to the first sub-conductor Gs1 and the second sub-conductor Gs2. Therefore, the signal processing circuit 31 is located above the first sub-conductor Gs1 and the second sub-conductor Gs2. As described above, the signal conversion unit 32 and the relay unit 33 are connected to the second sub-conductor Gs2. Therefore, the signal conversion unit 32 and the relay unit 33 are each located above the second sub-conductor Gs2.

<Connection between relay device 10 and repeater 11>
6 is an explanatory diagram of the connection between the relay device 10 and the repeater 11. In FIG. 6, a plan view of the main board Bm and the sub-board Bs is shown. As shown in FIG. 6, a recess 22a recessed toward the rear is provided on the front surface of the device connection body 22 of the relay device 10. A protrusion 34a protruding toward the rear is provided on the rear surface of the device connection body 34 of the repeater 11. The device connection body 34 is connected to the device connection body 22 by inserting the protrusion 34a of the device connection body 34 into the recess 22a of the device connection body 22. When the device connection body 22 is connected to the device connection body 34, the first main conductor Gm1 and the second main conductor Gm2 are connected to the first sub-conductor Gs1 and the second sub-conductor Gs2, respectively.

Figure 7 is a front view of the repeater 11 with the cover 36 removed. The repeater 11 further has two rails 37. As shown in Figures 5 and 7, one rail 37 is rod-shaped and protrudes leftward from the right wall inside the equipment box 35. The other rail 37 is rod-shaped and protrudes rightward from the left wall inside the equipment box 35.

The two rails 37 each extend in the front-rear direction. Therefore, the two rails 37 each extend from the open surface of the opening 35a provided in the equipment box 35 toward the bottom surface of the equipment box 35. The tip surface of the right rail 37 is provided with a recess 37a recessed to the right. The recess 37a is formed over the entire length of the right rail 37 in the front-rear direction. Similarly, the tip surface of the left rail 37 is provided with a recess 37a recessed to the left. The recess 37a is formed over the entire length of the left rail 37 in the front-rear direction. The right end of the sub-board Bs is disposed within the recess 37a of the right rail 37. The left end of the sub-board Bs is disposed within the recess 37a of the left rail 37.

Figure 8 is an explanatory diagram of how to insert the sub-board Bs. As shown in Figure 8, the manufacturer of the repeater 11 inserts the sub-board Bs into the equipment box 35 so that the communication line connector 30 and the equipment connector 34 are at the front and rear, respectively. At this time, the manufacturer slides the sub-board Bs to the rear with the right and left ends of the sub-board Bs placed in the recesses 37a of the two rails 37. The manufacturer inserts the protrusion 34a of the equipment connector 34 of the repeater 11 into the recess 22a of the equipment connector 22 of the repeater 10, and connects the equipment connector 34 to the equipment connector 22. The manufacturer then closes the opening 35a with the lid 36.

As described above, the equipment box 35 accommodates the sub-board Bs inserted from the open side of the opening 35a. Two rails 37 are provided inside the equipment box 35 of the repeater 11. This allows the manufacturer to easily accommodate the sub-board Bs in the equipment box 35 by moving the sub-board Bs along the two rails 37.

<Modification of the First Embodiment>
As long as the rail 37 is configured to slide the sub-substrate Bs, there is no problem. Therefore, the configuration of the rail 37 is not limited to a configuration in which the recess 37a is provided. For example, the recess may be provided in the sub-substrate Bs instead of the rail 37. In this case, a recess recessed to the left is provided on the right end surface of the sub-substrate Bs over the entire length in the front-rear direction. A recess recessed to the right is provided on the left end surface of the sub-substrate Bs over the entire length in the front-rear direction. Two rails 37 are disposed inside the two recesses of the sub-substrate Bs. In this case, it is not necessary to provide the recess 37a in the rail 37.

(Embodiment 2)
In the first embodiment, the device box 26 of the relay device 10 and the device box 35 of the repeater 11 do not have to be integrally formed.
The following describes the differences between the second embodiment and the first embodiment. Except for the configuration described below, the other configurations are common to the first embodiment. Therefore, the components common to the first embodiment are given the same reference numerals as the first embodiment, and the description thereof will be omitted.

<External appearance and internal structure of relay device 10 and repeater 11>
9 is a perspective view of the relay device 10 and the repeater 11 in the embodiment 2. The device box 26 of the relay device 10 has a hollow rectangular parallelepiped shape. The device box 35 of the repeater 11 has a hollow rectangular parallelepiped shape similar to the embodiment 1. The device box 35 is attached to the right surface of the device box 26.

Figure 10 is a cross-sectional view of the relay device 10 and the repeater 11. As shown in Figures 9 and 10, the equipment box 35 does not have an opening 35a. Therefore, the repeater 11 does not have a cover 36. The front wall of the equipment box 35 has a rectangular opening 35c in the front-rear direction. The opening 35c corresponds to the opening 36a in the first embodiment. The communication line connector 30 is fitted in the opening 35c. The front wall of the equipment box 26 has openings 26a and 26b, as in the first embodiment. The power connector 20 is fitted in the opening 26a. The bus connector 21 is fitted in the opening 26b.

The main board Bm of the relay device 10 has a rectangular shape. FIG. 10 shows a plan view of the main board Bm. As in the first embodiment, a first main conductor Gm1 and a second main conductor Gm2 are arranged inside the main board Bm. The first main conductor Gm1 is separated from the second main conductor Gm2. In the second embodiment, the first main conductor Gm1 and the second main conductor Gm2 each have a rectangular plate shape. The first main conductor Gm1 and the second main conductor Gm2 are arranged along the right side. The first main conductor Gm1 is located in front of the second main conductor Gm2.

The device connector 22 is disposed on the upper surface of the main board Bm, at the edge of the right side. An opening 26c that penetrates in the left-right direction is provided in the right wall of the device box 26. The device connector 22 is fitted into the opening 26c. The recess 22a is provided on the right surface of the device connector 22, and is recessed to the left.

As in the first embodiment, the first main conductor Gm1 is disposed below the power connector 20 and the bus connector 21. The first main conductor Gm1 and the second main conductor Gm2 are disposed below the device connector 22, the common mode choke coil 23, and the communication circuit 25. The second main conductor Gm2 is disposed below the power supply circuit 24.

Figure 10 shows a plan view of the sub-substrate Bs. As in the first embodiment, a first sub-conductor Gs1 and a second sub-conductor Gs2 are arranged inside the sub-substrate Bs. The first sub-conductor Gs1 is separated from the second sub-conductor Gs2. In the second embodiment, the first sub-conductor Gs1 and the second sub-conductor Gs2 are rectangular plate-shaped. The first sub-conductor Gs1 and the second sub-conductor Gs2 are arranged along the left side. The first sub-conductor Gs1 is located in front of the second sub-conductor Gs2.

The device connector 34 is disposed on the upper surface of the sub-board Bs, at the edge of the left side. The opening 35b is provided in the left wall of the device box 35 and penetrates in the left-right direction. As in the first embodiment, the device connector 34 is fitted into the opening 35b.

As in the first embodiment, the first sub-conductor Gs1 is disposed below the communication line connector 30. The first sub-conductor Gs1 and the second sub-conductor Gs2 are disposed below the device connector 34 and the common mode choke coil 45, respectively. The signal processing circuit 31 is located above the first sub-conductor Gs1 and the second sub-conductor Gs2. The signal conversion section 32 and the relay section 33 are located above the second sub-conductor Gs2.

<Connection between relay device 10 and repeater 11>
Fig. 11 is an explanatory diagram of the connection between the relay device 10 and the repeater 11. Fig. 11 shows a plan view of the main board Bm and the sub-board Bs. As described above, the device connection body 22 of the relay device 10 is disposed on the edge portion of the right side of the main board Bm. The right surface of the device connection body 22 is provided with a recess 22a that is recessed to the left side. The device connection body 34 of the repeater 11 is disposed on the edge portion of the left side of the sub-board Bs. The left surface of the device connection body 34 is provided with a protrusion 34a that protrudes to the left side.

The recess 22a of the device connector 22 is exposed to the outside of the device box 26. Similarly, the protrusion 34a of the device connector 34 is exposed to the outside of the device box 35. The manufacturer brings the device box 35 close to the device box 26 from the right side of the device box 26. The manufacturer inserts the protrusion 34a of the device connector 34 into the recess 22a of the device connector 22. This connects the device connector 34 to the device connector 22.

As described above, the repeater 11 is connected from the right side of the device box 26 of the repeater device 10. Therefore, the repeater 11 can be connected to the repeater device 10 regardless of the size of the sub-board Bs of the repeater 11. The repeater 11 to be connected to the repeater device 10 can be easily changed to a repeater having a larger sub-board Bs.
The repeater 11 and the communication device in the second embodiment have the same effects as those of the first embodiment, except for the effect obtained by providing the rail 37 .

(Embodiment 3)
In the second embodiment, the configuration of the repeater 11 is not limited to the configuration in which the repeater 11 is connected to the right side of the device box 26 of the repeater device 10 .
The following describes the differences between the third embodiment and the second embodiment. Except for the configuration described below, the other configurations are common to the second embodiment. Therefore, the same reference numerals as those in the second embodiment are used for the components common to the second embodiment, and the description thereof will be omitted.

<External appearance and internal structure of relay device 10 and relay unit 11>
12 is a perspective view of the relay device 10 and the repeater 11 in the third embodiment. As shown in FIG. 12, in the third embodiment, the equipment case 35 of the repeater 11 is attached to the upper surface of the equipment case 26.

Figure 13 is a plan view of the main board Bm. An equipment connection body 22 is disposed on the upper surface of the main board Bm of the relay device 10. The equipment connection body 22 protrudes upward from the upper surface of the main board Bm. As described in the explanation of the first embodiment, circuit elements such as a power supply circuit 24 or a communication circuit 25 are disposed on the upper surface of the main board Bm. The upper side is perpendicular to the upper surface of the main board Bm. The recess 22a is provided on the upper surface of the equipment connection body 22 and is recessed downward. The first main conductor Gm1 and the second main conductor Gm2 are disposed below the equipment connection body 22.

Figure 14 is a bottom view of the sub-board Bs. The device connector 34 is disposed on the lower surface of the sub-board Bs of the repeater 11. The device connector 34 protrudes downward from the lower surface of the sub-board Bs. As described in the description of the first embodiment, circuit elements such as the signal processing circuit 31, the signal conversion section 32, and the relay section 33 are disposed on the upper surface of the sub-board Bs. The upper surface of the sub-board Bs functions as a circuit surface. The lower side is perpendicular to the upper surface of the sub-board Bs. The protrusion 34a is provided on the lower surface of the device connector 34 and protrudes downward. The first sub-conductor Gs1 and the second sub-conductor Gs2 are disposed on the upper side of the device connector 34.

Figure 15 is a cross-sectional view of the relay device 10 and the repeater 11. Figure 15 shows the right side of the main board Bm and the sub-board Bs. With respect to the relay device 10, the opening 26c is provided in the upper wall of the device box 26 and penetrates in the vertical direction. The device connector 22 is fitted into the opening 26c. As described above, the upper surface of the device connector 22 is provided with a recess 22a.

With respect to the repeater 11, the opening 35b is provided in the bottom wall of the equipment case 35 and penetrates in the vertical direction. The device connector 34 is fitted into the opening 35b. As described above, the protrusion 34a protrudes downward from the bottom surface of the device connector 34.

<Connection between relay device 10 and repeater 11>
Fig. 16 is an explanatory diagram of the connection between the relay device 10 and the repeater 11. Fig. 16 shows the side surfaces of the main board Bm and the sub-board Bs. As described above, the device connector 22 is fitted into the opening 26c provided in the upper wall of the device box 26. The recess 22a of the device connector 22 is exposed to the outside of the device box 26. As described above, the device connector 34 is fitted into the opening 35b provided in the lower wall of the device box 35. The protrusion 34a of the device connector 34 is exposed to the outside of the device box 35.

The manufacturer brings the device box 35 close to the device box 26 from the top side of the device box 26. The manufacturer inserts the protrusion 34a of the device connector 34 into the recess 22a of the device connector 22. This connects the device connector 34 to the device connector 22. The device connector 22 of the relay device 10 is connected at the lower end (tip) of the device connector 34.

As described above, the repeater 11 is connected from the upper side of the device box 26 of the repeater device 10. Therefore, the repeater 11 can be connected to the repeater device 10 regardless of the size of the sub-board Bs of the repeater 11. The repeater 11 to be connected to the repeater device 10 can be easily changed to a repeater having a larger sub-board Bs.
The repeater 11 and the communication device in the third embodiment each have the same effects as those in the second embodiment.

<Modifications of the Second and Third Embodiments>
The repeater 11 in each of the second and third embodiments may be configured to slide the sub-board Bs along the rail 37, as in the first embodiment. For example, the communication line connection body 30 is disposed on the edge portion of the right side of the sub-board Bs. In this case, the rail 37 extending in the left-right direction is provided on the front and rear walls of the equipment box 35. An opening is provided on the right wall of the equipment box 35. The sub-board Bs is inserted into the equipment box 35 from the open side of this opening. The opening is covered by a lid, as in the first embodiment. An opening is provided in the lid. The communication line connection body 30 is fitted into the opening in the lid. A recess is provided on the right side of the communication line connection body 30.

In the second and third embodiments, mounting members for mounting the relay device 10 and the repeater 11 may be provided on the left or right surface of the device box 26 and the equipment box 35. In this case, for example, a part of the mounting member is provided on the left or right surface of the device box 26. The other part of the mounting member is provided on the left or right surface of the equipment box 35.

(Embodiment 4)
In the first embodiment, the first main conductor Gm1 of the relay device 10 is connected to the first sub-conductor Gs1 of the relay 11 via the equipment connection body 22 and the device connection body 34. The connection between the first main conductor Gm1 and the first sub-conductor Gs1 is not limited to the connection via the equipment connection body 22 and the device connection body 34.
The following describes the differences between the first embodiment and the fourth embodiment. Except for the configuration described below, the other configurations are common to the first embodiment. Therefore, the same reference numerals as those in the first embodiment are used for the components common to the first embodiment, and the description thereof will be omitted.

<Internal Structure of Relay Device 10 and Repeater 11>
17 is a cross-sectional view of the relay device 10 and the repeater 11 in the fourth embodiment. In the relay device 10, the main board Bm is accommodated in the device box 26, as in the first embodiment. The main board Bm is fixed to the bottom wall of the device box 26 by four device screws Fm1 and Fm2. The second main conductor Gm2 is disposed below the device connection body 22. In the fourth embodiment, the first main conductor Gm1 is not disposed below the device connection body 22. The first main conductor Gm1 is disposed near the front wall.

In the repeater 11, as in the first embodiment, the sub-board Bs is housed in the equipment case 35. The sub-board Bs is fixed to the bottom wall of the equipment case 35 by four equipment screws Fs1 and Fs2.

The equipment box 35 does not have an opening 35a. Therefore, the repeater 11 does not have a cover 36. The front wall of the equipment box 35 has a rectangular opening 35c in the front-rear direction, as in the second embodiment. The opening 35c corresponds to the opening 36a in the first embodiment. The communication line connector 30 is fitted into the opening 35c. The second sub-conductor Gs2 is disposed below the device connector 34. In the fourth embodiment, the first sub-conductor Gs1 is not disposed below the device connector 34. The first sub-conductor Gs1 is disposed near the front wall.

<Conduction Between First Main Conductor Gm1 and First Sub-Conductor Gs1>
18 is an explanatory diagram of the conduction between the first main conductor Gm1 and the first sub-conductor Gs1. In FIG. 18, a cross section around the device screw Fm1 of the relay device 10 and a cross section around the equipment screw Fs1 of the relay 11 are shown.

The main board Bm of the relay device 10 has an insulating plate 50. The insulating plate 50 has insulating properties. The first main conductor Gm1 is arranged within the insulating plate 50. The insulating plate 50 and the first main conductor Gm1 each have through holes 50h and Am that penetrate in the vertical direction. The through hole 50h is connected to the through hole Am. In addition, the bottom wall of the device box 26 has a screw hole 26h that penetrates in the vertical direction. The through holes 50h and Am each connect to the screw hole 26h. The surfaces of the through holes 50h and Am are covered with conductive device plating 51. The device plating 51 further covers the edge portion of the through hole 50h on the upper surface of the insulating plate 50. The device plating 51 is conductive with the first main conductor Gm1.

The threaded portion of the device screw Fm1 is passed through the through holes 50h and Am. The device screw Fm1 passes through the inside of the device plating 51. The device screw Fm1 is inserted into the screw hole 26h while passing through the through holes 50h and Am. In this state, the device screw Fm1 is tightened in the screw hole 26h. When the device screw Fm1 is tightened, the device screw Fm1 comes into contact with the device plating 51 and the device box 26. In the fourth embodiment, the device box 26 and the equipment box 35, which are integrally formed, are each conductive. The device screw Fm1 is also conductive. When the device screw Fm1 comes into contact with the device plating 51 and the device box 26, the first main conductor Gm1 is conductive to the device box 26 via the device plating 51 and the device screw Fm1.

Similarly, the sub-substrate Bs of the repeater 11 has an insulating plate 60. The insulating plate 60 has insulating properties. The first sub-conductor Gs1 is disposed within the insulating plate 60. The insulating plate 60 and the first sub-conductor Gs1 each have through holes 60h and As that penetrate in the vertical direction. The through hole 60h is connected to the through hole As. In addition, the bottom wall of the equipment box 35 has a screw hole 35h that penetrates in the vertical direction. The through holes 60h and As each communicate with the screw hole 35h. The surfaces of the through holes 60h and As are covered with conductive equipment plating 61. The equipment plating 61 further covers the edge portion of the through hole 60h on the upper surface of the insulating plate 60. The equipment plating 61 is electrically connected to the first sub-conductor Gs1.

The threaded portion of the equipment screw Fs1 is passed through the through holes 60h and As. The equipment screw Fs1 passes through the inside of the equipment plating 61. With the equipment screw Fs1 passing through the through holes 60h and As, the equipment screw Fs1 is inserted into the screw hole 35h. In this state, the equipment screw Fs1 is tightened in the screw hole 35h. When the equipment screw Fs1 is tightened, the equipment screw Fs1 contacts the equipment plating 61 and the equipment box 35. The equipment screw Fs1 is conductive. Therefore, the first sub-conductor Gs1 is conductive to the equipment box 35 via the equipment plating 61 and the equipment screw Fs1. The equipment screw Fs1 and the through hole 60h function as a second screw and a second through hole, respectively.

As described above, the device box 26 and the equipment box 35 are integrally formed. Therefore, the device box 26 is electrically connected to the equipment box 35. Therefore, in the fourth embodiment, the first main conductor Gm1 is electrically connected to the first sub-conductor Gs1 via the device plating 51, the device screw Fm1, the housing box H, the equipment screw Fs1, and the equipment plating 61. In the fourth embodiment, the first main conductor Gm1 is connected to the first sub-conductor Gs1 without passing through the equipment connector 22 and the equipment connector 34.

When the main board Bm is fixed to the equipment box 26 by tightening the equipment screw Fm2, the equipment screw Fm2 does not contact the second main conductor Gm2 and is not electrically connected to the second main conductor Gm2. Similarly, when the sub-board Bs is fixed to the equipment box 35 by tightening the equipment screw Fs2, the equipment screw Fs2 does not contact the second sub-conductor Gs2 and is not electrically connected to the second sub-conductor Gs2.
In addition, when the device screw Fm2 has insulating properties, the device screw Fm2 may contact the second main conductor Gm2. When the equipment screw Fs2 has insulating properties, the equipment screw Fs2 may contact the second sub-conductor Gs2.

The repeater 11 and communication device in embodiment 4 have the same effects as embodiment 1, except for the effect obtained by providing the rail 37.

<Modifications of the Second to Fourth Embodiments>
In the fourth embodiment, the repeater 11 may be configured to slide the sub-substrate Bs along the rail 37, as in the first embodiment. In each of the second and third embodiments, the electrical continuity of the first main conductor Gm1 may be realized by using the device screw Fm1, as in the fourth embodiment. Furthermore, the electrical continuity of the first sub-conductor Gs1 may be realized by using the device screw Fs1. In this case, the device box 26 and the device box 35 are conductive. For example, the electrical continuity of the device box 26 and the device box 35 is realized by bringing the device box 26 into contact with the device box 35.

(Embodiment 5)
In the first embodiment, the device to which the repeater 11 is connected is not limited to the repeater device 10 .
The following describes the differences between the fifth embodiment and the first embodiment. Except for the configuration described below, the other configurations are common to the first embodiment. Therefore, the same reference numerals as those in the first embodiment are used for the components common to the first embodiment, and the description thereof will be omitted.

<Configuration of communication system 1>
Fig. 19 is a block diagram showing the main configuration of a communication system 1 in embodiment 5. Comparing embodiments 1 and 5, the devices connected to the repeater 11 are different. The communication system 1 in embodiment 5 includes a power supply device 15 instead of the repeater 10. A DC power supply 12 supplies power to the power supply device 15. The power supply device 15 supplies power to the repeater 11. In embodiment 5, a plurality of ECUs 14 are connected to the repeater 11. The repeater 11 relays communication between two ECUs 14, similar to embodiment 1.

<Configuration of power supply device 15>
The power supply device 15 has a configuration similar to that of the relay device 10 in the first embodiment, except that one or more bus connectors 21 and a communication circuit 25 are removed. The relay 11 is attached to the device connector 22 of the power supply device 15. This connects the relay 11 to the device connector 22 of the power supply device 15. The relay 11 and the communication device in the fifth embodiment have the same effects as those in the first embodiment. FIG. 19 shows an example in which the first main conductor Gm1 and the second main conductor Gm2 are connected by a second inductor 23b. As described in the first embodiment, the first main conductor Gm1 and the second main conductor Gm2 may be connected by a resistor.

<Modification of the fifth embodiment>
In the fifth embodiment, the repeater 11 may be configured similarly to any one of the second to fourth embodiments.

(Embodiment 6)
In the first embodiment, the main board Bm and the sub-board Bs are respectively housed in the device box 26 and the equipment box 35. However, the equipment box 35 may be provided on the main board Bm.
The following describes the differences between the sixth embodiment and the first embodiment. Except for the configuration described below, the other configurations are common to the first embodiment. Therefore, the same reference numerals as those in the first embodiment are used for the components common to the first embodiment, and the description thereof will be omitted.

<Configuration of relay device 10>
20 is a block diagram showing the main configuration of the relay device 10 in the sixth embodiment. The relay device 10 in the sixth embodiment has the components of the relay device 10 in the first embodiment except for the device connection body 22. In the relay device 10 in the sixth embodiment, the power supply circuit 24, the communication circuit 25, the first main conductor Gm1, and the second main conductor Gm2 are connected to the relay 11 without the device connection body 22. Each of the components of the relay device 10 functions in the same manner as in the first embodiment. The relay device 11 is attached to the relay device 10. As a result, the power supply circuit 24, the communication circuit 25, the first main conductor Gm1, and the second main conductor Gm2 of the relay device 10 are connected to the relay 11.

<Configuration of repeater 11>
21 is a block diagram showing the main configuration of the repeater 11. As in the first embodiment, the power supply circuit 24 is connected to the signal conversion units 32 and the relay unit 33 via the device connector 34. The communication circuit 25 is connected to the relay unit 33 via the device connector 34. The second main conductor Gm2 is connected to the second sub-conductor Gs2. In the sixth embodiment, the first main conductor Gm1 is connected to the first sub-conductor Gs1 without going through the device connector 34.

<Arrangement of repeater 11>
FIG. 22 is a plan view of the relay device 10 and the repeater 11. FIG. 22 shows an example in which the number of bus connectors 21 is two. As shown in FIG. 22, the relay device 10 further includes a main board Bm. Inside the main board Bm, a first main conductor Gm1 and a second main conductor Gm2 are arranged. Each of the first main conductor Gm1 and the second main conductor Gm2 has a rectangular plate shape. The first main conductor Gm1 and the second main conductor Gm2 are arranged in the front-rear direction of the relay device 10. FIG. 22 shows the upper surfaces of the main board Bm, the first main conductor Gm1, and the second main conductor Gm2. The upper and lower surfaces of the main board Bm, the first main conductor Gm1, and the second main conductor Gm2 are the main surfaces.

On the upper surface of the main board Bm, a repeater 11, a power connector 20, two bus connectors 21, a common mode choke coil 23, a power circuit 24, and a communication circuit 25 are arranged. As described in the description of the first embodiment, the power connector 20 is connected to the first main conductor Gm1. The power circuit 24 is connected to the second main conductor Gm2. The repeater 11, the common mode choke coil 23, and the communication circuit 25 are each connected to both the first main conductor Gm1 and the second main conductor Gm2. The connection to the first main conductor Gm1 or the second main conductor Gm2 is realized by a through hole, a conductive pattern, or the like.

<Appearance of repeater 11>
Fig. 23 is an explanatory diagram of the external appearance of the repeater 11. Fig. 23 shows the front, rear, and side of the repeater 11. The equipment box 35 of the repeater 11 has a hollow rectangular parallelepiped shape, similar to the first embodiment. An opening 35d is provided in the front wall of the equipment box 35.

Two first protrusions 38f and two second protrusions 38r protrude downward (outside the equipment box 35) from the bottom surface of the equipment box 35. The two first protrusions 38f are aligned in the left-right direction. The two second protrusions 38r are also aligned in the left-right direction. The first protrusions 38f and the second protrusions 38r are disposed on the front and rear sides, respectively. The upper side of FIG. 22 corresponds to the front side of the relay device 10 and the repeater 11. The communication line connector 30 is inserted into the equipment box 35 through the opening 35d.

24 is a cross-sectional view of the repeater 11. As in the first embodiment, the sub-substrate Bs is housed in the device case 35. The first sub-conductor Gs1 and the second sub-conductor Gs2 are arranged inside the sub-substrate Bs. As shown in FIGS. 23 and 24, the communication line connector 30 is a hollow rectangular parallelepiped with one side open. As shown in FIG. 23, an opening 30a is provided on the front side of the communication line connector 30. For example, the end of a cable including multiple communication lines Lc is inserted into the opening 30a of the communication line connector 30. As a result, the multiple communication lines Lc are connected to the communication line connector 30. As shown in FIG. 24, the rear side of the communication line connector 30 blocks the opening 35d of the device case 35. The main board Bm is provided with multiple through holes 27 that penetrate in the vertical direction. The first protrusion 38f and the second protrusion 38r of the repeater 11 are inserted into the through holes 27 of the main board Bm.

Then, the first protrusion 38f and the second protrusion 38r are each connected to the main board Bm by solder. This fixes the device box 35 to the main board Bm. The device box 35 and the first protrusion 38f are conductive. The first protrusion 38f is electrically connected to the first main conductor Gm1 arranged inside the main board Bm, for example, by solder.

As shown in FIG. 24, the front end surface of the sub-substrate Bs is connected to the rear surface of the communication line connector 30. The communication line connector 30, a plurality of signal processing circuits 31, a plurality of signal conversion sections 32, a relay section 33, and a device connector 34 are arranged on the main surface of the sub-substrate Bs. The equipment box 35 is electrically connected to the first sub-conductor Gs1 via a conductor (not shown). As described above, the first protrusion 38f protrudes from the equipment box 35. Therefore, the first protrusion 38f is electrically connected to the equipment box 35. As a result, the first protrusion 38f is electrically connected to the first sub-conductor Gs1 via the equipment box 35.

As described above, when the equipment box 35 of the repeater 11 is fixed to the main board Bm by soldering, the first protrusion 38f is electrically connected to the first main conductor Gm1. Therefore, the first sub-conductor Gs1 is electrically connected to the first main conductor Gm1 via the equipment box 35 and the first protrusion 38f. The first main conductor Gm1 and the first sub-conductor Gs1 are treated as one conductor.
The component box 35 is spaced apart from the second sub-conductor Gs2. The component box 35 is not directly electrically connected to the second main conductor Gm2 via a conductor.

Figure 25 is another cross-sectional view of the repeater 11. The device connector 34 of the repeater 11 has conductive rods 34p. The conductive rods 34p are so-called lead pins. As shown in Figure 25, an insertion hole 47 into which the conductive rods 34p are inserted is provided on the rear side of the sub-substrate Bs. The insertion hole 47 penetrates in the vertical direction. The number of each of the conductive rods 34p and the insertion holes 47 is two or more.

The bottom wall of the device box 35 is provided with a through hole 35i that penetrates in the vertical direction. The top surface of the main board Bm of the relay device 10 is provided with an insertion hole 28 into which the conductive rod 34p is inserted. The conductive rod 34p passes through the through hole 35i. In this state, the conductive rod 34p is inserted into the two insertion holes 28 and 47. In the insertion hole 28, the conductive rod 34p is connected to the main board Bm by solder. In the insertion hole 47, the conductive rod 34p is connected to the sub-board Bs by solder. Therefore, the conductive rod 34p of the device connector 34 connects the sub-board Bs and the main board Bm of the relay device 10. The conductive rod 34p is electrically connected to the conductive patterns provided on the main board Bm and the sub-board Bs by solder.

Inside the through hole 35i, the space between the conductive rod 34p and the equipment box 35 is filled with an insulator. The equipment box 35 is separated from the conductive rod 34p and is not electrically connected to the conductive rod 34p.

The device connection body 34 has at least three conductive rods 34p. As shown in FIG. 21, the first conductive rod 34p connects the communication circuit 25 of the relay device 10 and the relay unit 33 of the relay 11. The second conductive rod 34p connects the power supply circuit 24 of the relay device 10 and the signal conversion unit 32 and the relay unit 33 of the relay 11. Therefore, power is supplied from the power supply circuit 24 to the signal conversion unit 32 and the relay unit 33 through the conductive rod 34p of the device connection body 34. The third conductive rod 34p connects the second main conductor Gm2 of the relay device 10 and the second sub-conductor Gs2 of the relay 11. Therefore, the second main conductor Gm2 is conductive to the second sub-conductor Gs2. Therefore, the second main conductor Gm2 and the second sub-conductor Gs2 are treated as one conductor.
The repeater 11 and communication device in the sixth embodiment have the same effects as those of the first embodiment, except for the effect obtained by providing the rail 37 .

<Modification of the Sixth Embodiment>
The repeater 11 of the sixth embodiment may be configured to slide the sub-board Bs along the rails 37, similar to the first embodiment. Also, similar to the fourth embodiment, electrical continuity between the equipment box 35 and the first main conductor Gm1 may be achieved by using an equipment screw Fs1.

(Embodiment 7)
In the sixth embodiment, the configuration of the device connector 34 of the repeater 11 is not limited to a configuration having the conductive rod 34p. Moreover, the communication line connector 30 is not limited to a hollow rectangular parallelepiped shape with one side open. Furthermore, the method of achieving electrical continuity between the first main conductor Gm1 of the repeater 10 and the first sub-conductor Gs1 of the repeater 11 is not limited to a method of achieving electrical continuity using the device box 35 and the first protrusion 38f.
The following describes the differences between the seventh embodiment and the sixth embodiment. Except for the configuration described below, the seventh embodiment is the same as the sixth embodiment. Therefore, the components common to the sixth embodiment are given the same reference numerals as the sixth embodiment, and the description thereof will be omitted.

<Internal structure of repeater 11>
26 is a cross-sectional view of a repeater in the seventh embodiment. As shown in FIG. 26, in the repeater 11, a plate-shaped device connector 34 protrudes rearward from the rear end surface of the sub-board Bs. The device connector 34 is flexible. The device connector 34 is, for example, an FPC (Flexible Printed Circuit). One end of the device connector 34 is installed on the sub-board Bs. A through hole 35j penetrating in the left-right direction is provided in the rear wall of the device box 35. The device connector 34 is inserted into the through hole 35j and exposed to the rear side of the device box 35. A plate-shaped terminal is connected to the other end of the device connector 34.

In the relay device 10, a rectangular parallelepiped connector C, which is connected to the device connector 34, is installed on the top surface of the main board Bm. The top surface of the connector C is provided with a recess that is recessed downward. The terminal of the device connector 34 is inserted into the recess of the connector C. This connects the device connector 34 to the connector C. Since the device connector 34 is flexible, the connection between the connector C and the device connector 34 can be easily achieved.

The device connector 34 is electrically connected to the conductive pattern provided on the sub-board Bs. The connector C is electrically connected to the conductive pattern provided on the main board Bm. Therefore, by connecting the device connector 34 to the connector C, the device connector 34 connects the sub-board Bs and the main board Bm of the relay device 10. The power supply circuit 24 of the relay device 10 supplies power to the signal conversion unit 32 and the relay unit 33 via the device connector 34.

The front side of the sub-board Bs has an insertion hole 48 that penetrates in the vertical direction. The repeater 11 has a conductive rod 39. The conductive rod 39 is a so-called lead pin. The conductive rod 39 is inserted into the insertion hole 48. The lower wall of the equipment box 35 has a through hole 35k that penetrates in the vertical direction. The upper surface of the main board Bm of the repeater 10 has an insertion hole 29 into which the conductive rod 39 is inserted. The conductive rod 39 passes through the through hole 35k. In this state, the conductive rod 39 is inserted into the two insertion holes 29 and 48. In the insertion hole 29, the conductive rod 39 is connected to the main board Bm by solder. The conductive rod 39 is electrically connected to the first main conductor Gm1 provided on the main board Bm, for example, by solder.

In the insertion hole 48, the conductive rod 39 is connected to the sub-substrate Bs by solder. The conductive rod 39 is electrically connected to the first sub-conductor Gs1 provided on the sub-substrate Bs, for example, by solder. As described above, in the seventh embodiment, the first main conductor Gm1 and the first sub-conductor Gs1 are electrically connected by the conductive rod 39.

A plate-shaped communication line connection body 30 protrudes forward from the front end face of the sub-board Bs. The communication line connection body 30 is an edge connector. A plurality of conductive patterns are arranged on the upper surface of the communication line connection body 30. The communication line connection body 30 is inserted into an opening 35d of an equipment case 35 and is exposed to the front side of the equipment case 35. For example, the plurality of communication lines Lc are housed in a cable. The cable has a recess. The communication line connection body 30 is inserted into the recess of the cable. As a result, the communication line connection body 30 is connected to the plurality of communication lines Lc.
The repeater 11 and the communication device in the seventh embodiment have the same effects as those in the sixth embodiment.

<Modification of the Seventh Embodiment>
In the seventh embodiment, the shape of the device connector 34 may be a rectangular parallelepiped. In this case, the device connector 34 has a recess. The connector C has a protrusion. The protrusion of the connector C is connected to the recess of the device connector 34. The device connector 34 may be an edge connector. In this case, the device connector 34 protrudes forward from the front surface (end surface) of the sub-substrate Bs. The shape of the communication line connector 30 may be the same as that of the sixth embodiment. Conduction between the first main conductor Gm1 and the first sub-conductor Gs1 may be achieved in the same manner as in the sixth embodiment.

(Embodiment 8)
In the sixth embodiment, the equipment box 35 of the relay 11 is fixed to the upper surface of the main board Bm of the relay device 10 by soldering. However, the method of fixing the equipment box 35 is not limited to the method using soldering.
The following describes the differences between the eighth embodiment and the sixth embodiment. Except for the configuration described below, the eighth embodiment is the same as the sixth embodiment. Therefore, the components common to the sixth embodiment are given the same reference numerals as the sixth embodiment, and the description thereof will be omitted.

<Appearance of repeater 11>
Fig. 27 is a front view of the repeater 11 in the eighth embodiment. The repeater 11 in the eighth embodiment has two first protrusions 70 instead of the two first protrusions 38f. As shown in Fig. 27, one of the first protrusions 70 protrudes leftward from the left surface of the equipment case 35. The other first protrusion 70 protrudes rightward from the right surface of the equipment case 35. The first protrusions 70 are provided with a through hole 70a that penetrates in the up-down direction.

Two screw holes 80 are provided on the upper main surface of the main board Bm of the relay device 10. Two conductive screws 71 having conductivity are passed through each of the two through holes 70a. In this state, the two conductive screws 71 are inserted into the two screw holes 80, respectively. The two conductive screws 71 are then tightened. By tightening the two conductive screws 71, the equipment box 35 is fixed to the upper surface of the main board Bm. When the equipment box 35 is fixed, the top of the conductive screw 71 comes into contact with the first protrusion 70.

The first protrusion 70 is conductive. As described in the description of the sixth embodiment, the equipment box 35 is conductive and is electrically connected to the first sub-conductor Gs1. Since the first protrusion 70 is provided on the equipment box 35, the equipment box 35 is electrically connected to the first protrusion 70. Therefore, the first protrusion 70 is electrically connected to the first sub-conductor Gs1 via the equipment box 35. When the equipment box 35 is fixed, the first protrusion 70 is in contact with the conductive screw 71, so that the conductive screw 71 is electrically connected to the first protrusion 70. The conductive screw 71 is electrically connected to the first main conductor Gm1 in the main board Bm. As a result, the first sub-conductor Gs1 is electrically connected to the first main conductor Gm1 via the equipment box 35, the first protrusion 70, and the conductive screw 71.
The repeater 11 and the communication device in the eighth embodiment have the same effects as those in the sixth embodiment.

<Modifications of the Sixth to Eighth Embodiments>
In the eighth embodiment, a second protrusion configured similarly to the first protrusion 70 may be used instead of the second protrusion 38r. In this case as well, a screw is passed through the through hole of the second protrusion and inserted into the screw hole of the main board Bm. The screw is then tightened. In each of the sixth and seventh embodiments, the repeater 11 may have the first protrusion 70 instead of the first protrusion 38f, similar to the eighth embodiment. In this case as well, the device case 35 is fixed to the upper surface of the main board Bm by using a conductive screw 71, similar to the eighth embodiment.

(Embodiment 9)
In the sixth embodiment, the method for achieving electrical continuity between the second main conductor Gm2 and the second sub-conductor Gs2 is not limited to the method using the conductive rod 34p.
The following describes the differences between the ninth embodiment and the sixth embodiment. Except for the configuration described below, the other configurations are common to the sixth embodiment. Therefore, the same reference numerals as in the sixth embodiment are used for the components common to the sixth embodiment, and the description thereof will be omitted.

<Appearance of repeater 11>
28 is a side view of the repeater 11 in the ninth embodiment. The equipment case 35 has a first conductive portion 35f, a second conductive portion 35r, and a connecting portion 35m. The first conductive portion 35f and the second conductive portion 35r are disposed on the front and rear sides, respectively. The connecting portion 35m connects the first conductive portion 35f and the second conductive portion 35r. In the ninth embodiment, the shape of the equipment case 35 is the same as that in the first embodiment.

The first conductive portion 35f and the second conductive portion 35r are conductive. The connecting portion 35m is insulating. The first conductive portion 35f is separated from the second conductive portion 35r by the connecting portion 35m. Two first protrusions 38f protrude downward from the lower surface of the first conductive portion 35f. Two second protrusions 38r protrude downward from the lower surface of the second conductive portion 35r. The second protrusions 38r are conductive like the first protrusions 38f.

The first conductive portion 35f of the equipment box 35 is electrically connected to the first sub-conductor Gs1 via a conductor (not shown). The first protrusion 38f is electrically connected to the first conductive portion 35f. When the equipment box 35 is fixed to the main board Bm of the relay device 10 by soldering, the first protrusion 38f is electrically connected to the first main conductor Gm1. Therefore, the first sub-conductor Gs1 is electrically connected to the first main conductor Gm1 via the first conductive portion 35f and the first protrusion 38f.

Similarly, the second conductive portion 35r of the equipment box 35 is electrically connected to the second sub-conductor Gs2 via a conductor not shown. The second protrusion 38r is electrically connected to the second conductive portion 35r. When the equipment box 35 is fixed to the main board Bm of the relay device 10 by soldering, the second protrusion 38r is electrically connected to the second main conductor Gm2. Therefore, the second sub-conductor Gs2 is electrically connected to the second main conductor Gm2 via the second conductive portion 35r and the second protrusion 38r.

As described above, the first protrusion 38f and the second protrusion 38r can be electrically connected to the first main conductor Gm1 and the second main conductor Gm2, respectively. Note that, in the repeater 11 of the ninth embodiment, the conductive rod 34p that connects the second main conductor Gm2 and the second sub-conductor Gs2 is not necessary.
The repeater 11 and the communication device in the ninth embodiment have the same effects as those in the sixth embodiment.

(Embodiment 10)
In the sixth embodiment, the second inductor 22b or the resistor connects the first main conductor Gm1 and the second main conductor Gm2. However, a member other than the second inductor 22b and the resistor may connect the first main conductor Gm1 and the second main conductor Gm2.
The following describes the differences between the tenth embodiment and the sixth embodiment. Except for the configuration described below, the other configurations are common to the sixth embodiment. Therefore, the components common to the sixth embodiment are given the same reference numerals as the sixth embodiment, and the description thereof will be omitted.

<Configuration of relay device 10>
29 is a block diagram showing a main configuration of the relay device 10 in the tenth embodiment. The relay device 10 in the tenth embodiment has the same components as the relay device 10 in the sixth embodiment except for the common mode choke coil 23. Thus, the relay device 10 has a first main conductor Gm1 and a second main conductor Gm2. The first main conductor Gm1 and the second main conductor Gm2 are respectively connected to the first sub-conductor Gs1 and the second sub-conductor Gs2 of the repeater 11. The relay device 10 in the tenth embodiment further has a second conductor Wr.

The power supply circuit 24 is directly connected to the power supply connector 20. One end of the second conductor Wr is connected to the power supply connector 20 and the first main conductor Gm1. The other end of the second conductor Wr is connected to the second main conductor Gm2. In this way, the first main conductor Gm1 and the second main conductor Gm2 are connected by the second conductor Wr.

The current flows from the positive electrode of the DC power supply 12 through the power supply circuit 24, the second main conductor Gm2, and the second conductor Wr in this order, and returns to the negative electrode of the DC power supply 12. The DC power supply 12 applies a voltage whose reference potential is the potential of the second main conductor Gm2 to the power supply circuit 24. The power supply circuit 24 reduces the voltage applied from the DC power supply 12 to a constant voltage such as 5V or 3.3V. The power supply circuit 24 applies the constant voltage generated by reducing the voltage to the repeater 11 and the communication circuit 25 as in the sixth embodiment. This supplies power to the repeater 11 and the communication circuit 25. The reference potential of the constant voltage is the potential of the second main conductor Gm2. As in the sixth embodiment, the noise that has entered the first sub-conductor Gs1 of the repeater 11 is output to the outside of the repeater 10 via the first main conductor Gm1 and the power supply connector 20.

Figure 30 is an explanatory diagram of the arrangement of the second conductor Wr. As shown in Figure 30, the second conductor Wr is arranged on the main surface of the main board Bm. One end of the second conductor Wr is located above the first main conductor Gm1 and is connected to one point on the first main conductor Gm1. The other end of the second conductor Wr is located above the second main conductor Gm2 and is connected to one point on the second main conductor Gm2.

The second conductor Wr has a resistance component. Since the second conductor Wr has a linear shape, the cross-sectional area of the second conductor Wr is small. Therefore, the resistance value of the resistance component of the second conductor Wr is large. Therefore, noise is less likely to pass through the second conductor Wr. Even if the potential of the first main conductor Gm1 fluctuates due to noise entering the first main conductor Gm1, the influence of the reference potential on the voltage or electrical signal, which is the potential of the second main conductor Gm2, is small. Similarly, even if the potential of the second main conductor Gm2 fluctuates due to noise entering the second main conductor Gm2, the influence of the reference potential on the voltage or signal, which is the potential of the first main conductor Gm1, is small.

The communication device in the tenth embodiment has the same effects as those in the sixth embodiment. As described in the sixth embodiment, the communication device includes a relay device 10 and a repeater 11.

<Modifications of the First to Fifth Embodiments>
The relay device 10 in each of the first to fourth embodiments may have a second conductor Wr, similar to the tenth embodiment, instead of the common mode choke coil 23. In this case, the power supply circuit 24 and the second conductor Wr are connected in the same manner as the tenth embodiment. The power supply circuit 24 functions in the same manner as the tenth embodiment. Similarly, the power supply device 15 in the fifth embodiment may have a second conductor Wr, similar to the sixth embodiment, instead of the common mode choke coil 23. In this case, the power supply circuit 24 and the second conductor Wr are connected in the same manner as the sixth embodiment. The power supply circuit 24 supplies power to the relay 11 in the same manner as the tenth embodiment.

<Modification of the Tenth Embodiment>
The configuration of the repeater 11 is not limited to that of the sixth embodiment. The repeater 11 of the tenth embodiment may be configured similarly to one of the repeaters 11 of the seventh to ninth embodiments.

(Embodiment 11)
In the sixth embodiment, the negative electrode of the DC power supply 12 is connected to the first main conductor Gm1 via the power supply connector 20. However, the negative electrode of the DC power supply 12 does not have to be connected to the first main conductor Gm1.
The following describes the differences between the eleventh embodiment and the sixth embodiment. Except for the configuration described below, the other configurations are common to the sixth embodiment. Therefore, the same reference numerals as those in the sixth embodiment are used for the components common to the sixth embodiment, and the description thereof will be omitted.

<Configuration of relay device 10>
31 is a block diagram showing a main configuration of the relay device 10 in the eleventh embodiment. The relay device 10 in the eleventh embodiment has the components of the relay device 10 in the sixth embodiment except for the common mode choke coil 23. Thus, the relay device 10 has a first main conductor Gm1 and a second main conductor Gm2. The first main conductor Gm1 and the second main conductor Gm2 are respectively connected to the first sub-conductor Gs1 and the second sub-conductor Gs2 of the repeater 11. The relay device 10 in the eleventh embodiment further has a connection part Pr.

The power supply circuit 24 is directly connected to the power supply connector 20. The power supply connector 20 is further connected to the second main conductor Gm2. The power supply connector 20 is not connected to the first main conductor Gm1. The connection part Pr is an inductor, a resistor, a conductor, or the like. The conductor has a resistance component. One end of the connection part Pr is connected to the first main conductor Gm1. The other end of the connection part Pr is connected to the second main conductor Gm2. Therefore, the first main conductor Gm1 and the second main conductor Gm2 are connected by the connection part Pr.

As described above, the connection part Pr is an inductor, a resistor, a conductor, or the like. Therefore, as in the sixth and tenth embodiments, even if the potential of the first main conductor Gm1 fluctuates due to noise entering the first main conductor Gm1, the reference potential has little effect on the voltage or electrical signal which is the potential of the second main conductor Gm2. Similarly, even if the potential of the second main conductor Gm2 fluctuates due to noise entering the second main conductor Gm2, the reference potential has little effect on the voltage or signal which is the potential of the first main conductor Gm1.

Figure 32 is an explanatory diagram of the arrangement of the connection part Pr. As shown in Figure 32, the connection part Pr is arranged on the main surface of the main board Bm. One end of the connection part Pr is located above the first main conductor Gm1 and is connected to one point on the first main conductor Gm1. The other end of the connection part Pr is located above the second main conductor Gm2 and is connected to one point on the second main conductor Gm2.

As shown in FIG. 32, in the relay device 10, the first main conductor Gm1 is not connected to the power connection body 20. Therefore, there is no need to place the first main conductor Gm1 near the power connection body 20. Therefore, as shown in FIG. 32, a plate-shaped conductor with a small main surface area can be used as the first main conductor Gm1. When a plate-shaped conductor with a small main surface area is used as the first main conductor Gm1, a plate-shaped conductor with a large main surface area can be used as the second main conductor Gm2. In this case, since the resistance value of the second main conductor Gm2 is small, the potential of the second main conductor Gm2 is stable.

The communication device in embodiment 11 has the same effects as embodiment 6.

<Modifications of the First to Fifth Embodiments>
The relay device 10 in each of the first to fourth embodiments may not have the common mode choke coil 23, but may have a connection part Pr similar to the eleventh embodiment. In this case, the power supply circuit 24 and the connection part Pr are connected similar to the eleventh embodiment. The power supply circuit 24 functions similar to the eleventh embodiment. Similarly, the power supply device 15 in the fifth embodiment may not have the common mode choke coil 23, but may have a connection part Pr similar to the eleventh embodiment. In this case, the power supply circuit 24 and the connection part Pr are connected similar to the eleventh embodiment. The power supply circuit 24 supplies power to the relay device 11 similar to the eleventh embodiment.

<Modification of Eleventh Embodiment>
The configuration of the repeater 11 is not limited to that of the sixth embodiment. The repeater 11 of the eleventh embodiment may be configured similarly to one of the repeaters 11 of the seventh to ninth embodiments.

(Embodiment 12)
In the sixth embodiment, the first sub-conductor Gs1 of the relay 11 is connected to the first main conductor Gm1 of the relay device 10. However, the first sub-conductor Gs1 does not have to be connected to the first main conductor Gm1.
The following describes the differences between the twelfth embodiment and the sixth embodiment. Except for the configuration described below, the other configurations are common to the sixth embodiment. Therefore, the same reference numerals as those in the sixth embodiment are used for the components common to the sixth embodiment , and the description thereof will be omitted.

<Configuration of repeater 11>
Fig. 33 is a block diagram showing a main configuration of the repeater 11 in embodiment 12. Fig. 34 is a circuit diagram of a signal processing circuit 31. The repeater 11 has a conductor connection element De. The conductor connection element De is an inductor, a resistor, a conductor, or the like. The conductor has a resistance component. As shown in Figs. 33 and 34, one end of the conductor connection element De is connected to the first sub-conductor Gs1. The other end of the conductor connection element De is connected to the second sub-conductor Gs2. Therefore, the conductor connection element De is connected between the first sub-conductor Gs1 and the second sub-conductor Gs2.

Figure 35 is a plan view of the sub-substrate Bs. Figure 35 shows the top surface of the sub-substrate Bs. As described in the explanation of embodiment 6, multiple insertion holes 47 are provided on the rear side of the sub-substrate Bs. Figure 35 shows an example in which the number of insertion holes 47 is six. The multiple insertion holes 47 are aligned in the left-right direction. A conductive rod 34p is inserted into each insertion hole 47. A first sub-conductor Gs1 and a second sub-conductor Gs2 are arranged inside the sub-substrate Bs.

As shown in Figs. 24 and 35, the first sub-conductor Gs1 and the second sub-conductor Gs2 each have a rectangular plate shape. The first sub-conductor Gs1 is disposed in front of the second sub-conductor Gs2. A common mode choke coil 45 and a conductor connection element De are disposed on the upper main surface of the sub-substrate Bs. Fig. 35 shows an example in which the number of each of the signal processing circuits 31 and the signal conversion units 32 is three. Therefore, three common mode choke coils 45 are disposed.

The common mode choke coil 45 is located above the first sub-conductor Gs1 and the second sub-conductor Gs2. One end of the conductor connection element De is located above the first sub-conductor Gs1. One end of the conductor connection element De is connected to the first sub-conductor Gs1, for example, using a through-hole. The other end of the conductor connection element De is located above the second sub-conductor Gs2. The other end of the conductor connection element De is connected to the second sub-conductor Gs2, for example, using a through-hole.

In embodiment 12, the first sub-conductor Gs1 is not electrically connected to the first main conductor Gm1. In embodiment 6, the first sub-conductor Gs1 is electrically connected to the first main conductor Gm1 via the device box 35 and the first protrusion 38f. In embodiment 12, as a first example, both or one of the device box 35 and the first protrusion 38f are insulating. As a second example, the connection between the first protrusion 38f and the first main conductor Gm1 is not realized.

The conductor connection element De is connected between the first sub-conductor Gs1 and the second sub-conductor Gs2. Therefore, even if noise enters the first sub-conductor Gs1 and the potential of the first sub-conductor Gs1 fluctuates, the reference potential has little effect on the voltage or signal which is the potential of the second sub-conductor Gs2. Similarly, even if noise enters the second sub-conductor Gs2 and the potential of the second sub-conductor Gs2 fluctuates, the reference potential has little effect on the voltage or signal which is the potential of the first sub-conductor Gs1.

The repeater 11 and communication device in embodiment 12 have the same effects as those in embodiment 6.

<Modification of the 12th embodiment>
In the twelfth embodiment, similarly to the sixth embodiment, the first sub-conductor Gs1 may be electrically connected to the first main conductor Gm1.

<Modifications of Embodiments 1 to 5 and 7 to 11>
In each of the first to fifth and seventh to eleventh embodiments, the conductor connection element De may be connected between the first sub-conductor Gs1 and the second sub-conductor Gs2, as in the case of the 12th embodiment. In this case, there is no problem even if the first sub-conductor Gs1 is not electrically connected to the first main conductor Gm1.

(Embodiment 13)
In the twelfth embodiment, the relay device 10 does not necessarily have to have the first main conductor Gm1.
The following describes the differences between the thirteenth embodiment and the twelfth embodiment. Except for the configuration described below, the other configurations are common to the thirteenth embodiment and the twelfth embodiment. Therefore, the components common to the thirteenth embodiment and the twelfth embodiment are given the same reference numerals as the twelfth embodiment, and the description thereof will be omitted.

<Configuration of relay device 10>
36 is a block diagram showing a configuration of a main part of the relay device 10 according to the embodiment 13. The relay device 10 according to the embodiment 13 has components other than the common mode choke coil 23 and the first main conductor Gm1 among the components of the relay device 10 according to the embodiment 13.

The power supply circuit 24 is directly connected to the power supply connector 20. The power supply connector 20 is further connected to the second main conductor Gm2. In the relay device 10, the first main conductor Gm1 is not provided, so the power supply connector 20 and the communication circuit 25 are not connected to the first main conductor Gm1.

In the thirteenth embodiment, the communication circuit 25 does not process an electrical signal with the potential of the first main conductor Gm1 as the reference potential. Therefore, when the communication circuit 25 receives a differential signal via the communication bus Lb, it converts the received differential signal into a voltage signal whose reference potential is the potential of the second main conductor Gm2. The communication circuit 25 acquires the data contained in the converted voltage signal.

Figure 37 is an explanatory diagram of the arrangement of the second main conductor Gm2. Since the first main conductor Gm1 is not provided in the relay device 10, as shown in Figure 37, a plate-shaped conductor with a large main surface area can be used as the second main conductor Gm2. In this case, since the resistance value of the second main conductor Gm2 is small, the potential of the second main conductor Gm2 is stable.

The repeater 11 in the 13th embodiment achieves the same effects as the repeater 11 in the 12th embodiment, except for the connection effect obtained by connecting the first main conductor Gm1 to the first sub-conductor Gs1. The communication device in the 13th embodiment achieves the same effects as the communication device in the 12th embodiment, except for the connection effect and the effect of the common mode choke coil 23.

<Modifications of the First to Thirteenth Embodiments>
In the seventh, eighth, tenth, and eleventh embodiments, the equipment box 35 may be configured similarly to the ninth embodiment. Here, in the eighth embodiment, the first protrusion 70 protrudes from the first conductive portion 35f. The second protrusion in the eighth embodiment is conductive and protrudes from the second conductive portion 35r. In this case, a conductive screw is inserted into the through hole of the second protrusion. The second sub-conductor Gs2 is electrically connected to the second main conductor Gm2 via the second conductive portion 35r, the second protrusion, and the screw. In the twelfth embodiment, when the first main conductor Gm1 and the second main conductor Gm2 are connected to the first sub-conductor Gs1 and the second sub-conductor Gs2, respectively, the equipment box 35 may be configured similarly to the ninth embodiment. In the fifth embodiment, the repeater 11 may be configured similarly to the sixth to thirteenth embodiments. In this case, the power supply device 15 does not have the equipment connector 22, as in the sixth embodiment.

The storage box H in the fourth embodiment may have a first conductive part, a second conductive part, and a connecting part, similar to the device connector 22 in the ninth embodiment. In this case, the first main conductor Gm1 is conductive to the first sub-conductor Gs1 via the device plating 51, the device screw Fm1, the first conductive part of the storage box H, the device screw Fs1, and the device plating 61. As with the device screw Fm1 and the device screw Fs1, by tightening the device screw Fm2 and the device screw Fs2, the second main conductor Gm2 and the second sub-conductor Gs2 can be conductive via the device plating 51, the device screw Fm2, the second conductive part of the storage box H, the device screw Fs2, and the device plating 61.

In the first to thirteenth embodiments, another communication device, for example, a camera, may be used instead of the ECU 14. The ECU 14 and a communication device different from the ECU 14 may be connected to the repeater 11. The communication system 1 in each of the first to fourth and sixth to thirteenth embodiments may further include a repeater 11, a plurality of communication devices (ECUs 14), and a power supply device 15. In this case, for example, two repeaters 11 are connected by a communication line Lc. A common DC power supply 12 supplies power to the repeater 10 and the power supply device 15. In the first to thirteenth embodiments, the first main conductor Gm1 may be connected to the first sub-conductor Gs1 via the device connector 34. In a configuration in which the device connector 34 has a plurality of conductive rods 34p, the first main conductor Gm1 is connected to the first sub-conductor Gs1 via one conductive rod 34p.

In the repeater 11 in the first to thirteenth embodiments, circuit elements may be arranged on both main surfaces of the sub-substrate Bs. In the first to thirteenth embodiments, the number of first protrusions 38f or the number of first protrusions 70 is not limited to two, and may be one or three or more. Also, in the first to thirteenth embodiments, the number of second protrusions 38r or the number of second protrusions configured similarly to the first protrusions 70 is not limited to two, and may be one or three or more.

In embodiments 1 to 13, the location where the first sub-conductor Gs1 and the second sub-conductor Gs2 are arranged is not limited to the inside of the sub-substrate Bs, but may be the main surface or end surface of the sub-substrate Bs. Similarly, the location where the first main conductor Gm1 and the second main conductor Gm2 are arranged is not limited to the inside of the main substrate Bm, but may be the main surface or end surface of the main substrate Bm.

In the first to thirteenth embodiments, the communication line Lc connected to the repeater 11 may be a communication bus. In this case, multiple ECUs 14 are connected to the communication line Lc. The communication via the communication line Lc is performed, for example, in the same manner as the communication via the communication bus Lb. The communication via the communication line Lc is, for example, communication according to the CAN communication protocol.

The technical features (constituent elements) described in the first to thirteenth embodiments can be combined with each other, and by combining them, new technical features can be formed.
The disclosed embodiments 1 to 13 are illustrative in all respects and should not be considered as limiting. The scope of the present invention is defined by the claims, not by the above meaning, and is intended to include all modifications within the meaning and scope of the claims.

1 Communication system 10 Relay device (power supply device)
11 Repeater (communication device)
12 DC power supply 13,14 ECU
15 Power supply device 20 Power supply connector 21 Bus connector 22 Device connector 22a, 37a Recess 23 Common mode choke coil (voltage conversion section)
23a, 45a First inductor 23b, 45b Second inductor 24 Power supply circuit 25 Communication circuit 26 Device box 26a, 26b, 26c, 30a, 35a, 35b, 35c, 35d, 36a Opening 26h, 35h, 80 Screw hole 27, 35i, 35j, 35k, 50h, 70a, Am, As Through hole 28, 29, 47, 48 Insertion hole 30 Communication line connector 31 Signal processing circuit (noise removal circuit)
32 Signal conversion section 33 Relay section 34 Device connection body 34a Protrusion 34p, 39 Conductive rod 35 Device box 35f First conductive portion 35m Connecting portion 35r Second conductive portion 36 Lid 37 Rail 38f, 70 First protrusion 38r Second protrusion 40a, 40b First suppressor 41a, 41b, 42 Resistor 43, 44a, 44b Capacitor 45 Common mode choke coil 46a, 46b Second suppressor 50, 60 Insulating plate 51 Device plating 60h Through hole (second through hole)
61 Equipment plating 71 Conductive screw Bm Main board Bs Sub-board C Connector De Conductive connection element Fm1, Fm2 Equipment screw Fs1 Equipment screw (second screw)
Fs2 Equipment screw Gm1 First main conductor (second power conductor)
Gm2 Second main conductor (power conductor)
Gs1 First sub-conductor (first conductor)
Gs2 Second sub-conductor (second conductor)
H: Storage box Lb: Communication bus Lc: Communication line M: Vehicle Pr: Connection part Wa, Wb: Conductor Wr: Second conductive wire

Claims (21)

A communication device that is attached to an in-vehicle device and receives a differential signal represented by a voltage difference between two electrical signals propagating through two conductors,
a noise removal circuit that removes noise from the two electrical signals using the potential of the first conductor as a reference potential;
a signal conversion unit that converts a differential signal represented by a voltage difference between the two electrical signals from which noise has been removed by the noise removal circuit into a voltage signal represented by a voltage whose reference potential is the potential of the second conductor;
and a device connector connected to a power supply device that supplies power,
the power supply device supplies power to the signal conversion unit by applying a voltage, the reference potential of which is the potential of the second conductor, to the signal conversion unit via the device connector ;
a substrate on which the first conductor and the second conductor are disposed;
the substrate has a circuit surface on which circuit elements are arranged;
the device connector is disposed on the substrate and protrudes in a direction perpendicular to the circuit surface;
The power supply device is connected to the tip of the device connector.
Communication device. A communication device that is attached to an in-vehicle device and receives a differential signal represented by a voltage difference between two electrical signals propagating through two conductors,
a noise removal circuit that removes noise from the two electrical signals using the potential of the first conductor as a reference potential;
a signal conversion unit that converts a differential signal represented by a voltage difference between the two electrical signals from which noise has been removed by the noise removal circuit into a voltage signal represented by a voltage whose reference potential is the potential of the second conductor;
A device connector that is connected to a power supply device that supplies power;
Equipped with
the power supply device supplies power to the signal conversion unit by applying a voltage, the reference potential of which is the potential of the second conductor, to the signal conversion unit via the device connector;
a substrate on which the first conductor and the second conductor are disposed;
a conductive box for accommodating the substrate;
a protrusion protruding outward from the box body and used for fixing the box body;
Equipped with
The protrusion is conductive and is electrically connected to the first conductor through the box.
Communication device. A communication device that is attached to an in-vehicle device and receives a differential signal represented by a voltage difference between two electrical signals propagating through two conductors,
a noise removal circuit that removes noise from the two electrical signals using the potential of the first conductor as a reference potential;
a signal conversion unit that converts a differential signal represented by a voltage difference between the two electrical signals from which noise has been removed by the noise removal circuit into a voltage signal represented by a voltage whose reference potential is the potential of the second conductor;
A device connector that is connected to a power supply device that supplies power;
Equipped with
the power supply device supplies power to the signal conversion unit by applying a voltage, the reference potential of which is the potential of the second conductor, to the signal conversion unit via the device connector;
a substrate on which the first conductor and the second conductor are disposed;
a conductive box for accommodating the substrate;
Equipped with
the substrate is provided with a second through hole through which a second screw having electrical conductivity passes;
the box body is provided with a screw hole into which the second screw passed through the second through hole is inserted,
When the second screw is fastened in the screw hole, the first conductor is electrically connected to the box body via the second screw.
Communication device. A communication device that is attached to an in-vehicle device and receives a differential signal represented by a voltage difference between two electrical signals propagating through two conductors,
a noise removal circuit that removes noise from the two electrical signals using the potential of the first conductor as a reference potential;
a signal conversion unit that converts a differential signal represented by a voltage difference between the two electrical signals from which noise has been removed by the noise removal circuit into a voltage signal represented by a voltage whose reference potential is the potential of the second conductor;
A device connector that is connected to a power supply device that supplies power;
Equipped with
the power supply device supplies power to the signal conversion unit by applying a voltage, the reference potential of which is the potential of the second conductor, to the signal conversion unit via the device connector;
a substrate on which the first conductor and the second conductor are disposed;
The device connector has a conductive rod having electrical conductivity,
The substrate is provided with an insertion hole into which the conductive rod is inserted.
Communication device. A communication device that is attached to an in-vehicle device and receives a differential signal represented by a voltage difference between two electrical signals propagating through two conductors,
a noise removal circuit that removes noise from the two electrical signals using the potential of the first conductor as a reference potential;
a signal conversion unit that converts a differential signal represented by a voltage difference between the two electrical signals from which noise has been removed by the noise removal circuit into a voltage signal represented by a voltage whose reference potential is the potential of the second conductor;
A device connector that is connected to a power supply device that supplies power;
Equipped with
The power supply device is
An equipment connector connected to the device connector;
a main conductor that is at the same potential as the second conductor and is connected to the device connector;
Equipped with
A voltage whose reference potential is the same as the potential of the second conductor is applied to the signal conversion unit via the appliance connector and the device connector, thereby supplying power to the signal conversion unit.
Communication device. The differential signal is a communication signal conforming to an Ethernet communication protocol, a communication signal using LVDS (Low Voltage Differential Signaling), or a communication signal conforming to USB (Universal Serial Bus).
The communication device according to any one of claims 1 to 5 . a conductor connection element connected between the first conductor and the second conductor;
The conductive connecting element is an inductor, a resistor or a conductor.
The communication device according to any one of claims 1 to 6 . a substrate on which the first conductor and the second conductor are disposed;
a box having an open surface and configured to accommodate the substrate inserted from the open surface;
The communication device according to claim 1 , further comprising: a rail provided within the box and extending from the open surface toward a bottom surface of the box. a substrate on which the first conductor and the second conductor are disposed;
The device connector is disposed on an edge portion of one side of the substrate,
The communication device according to claim 1 , wherein the first conductor and the second conductor are arranged along one side of the edge portion on which the device connector is arranged. a substrate on which the first conductor and the second conductor are disposed;
the substrate has a circuit surface on which circuit elements are arranged;
the device connector is disposed on the substrate and protrudes in a direction perpendicular to the circuit surface;
The communication device according to claim 1 , wherein the power supply device is connected to a tip end of the device connector. a substrate on which the first conductor and the second conductor are disposed;
a conductive box body that houses the substrate; and a protrusion that protrudes outward from the box body and is used to fix the box body,
The communication device according to claim 1 , wherein the protrusion is electrically conductive and is electrically connected to the first conductor via the box body. the protruding portion is provided with a through hole through which a conductive screw is inserted,
The box body is fixed by tightening the screws,
The communication device according to claim 11 , wherein the screw is electrically connected to the protrusion when the box is fixed. a second protrusion that is conductive, protrudes outward from the box body, and is used to fix the box body;
The box body is
a first conductive portion having electrical conductivity and in electrical communication with the first conductor;
a second conductive portion having electrical conductivity and in electrical communication with the second conductor;
a connecting portion having insulating properties and connecting the first conductive portion and the second conductive portion;
the protrusion protrudes from the first conductive portion,
The communication device according to claim 11 or 12 , wherein the second protrusion protrudes from the second conductive portion. a substrate on which the first conductor and the second conductor are disposed;
and a box body having electrical conductivity and accommodating the substrate;
the substrate is provided with a second through hole through which a second screw having electrical conductivity passes;
the box body is provided with a screw hole into which the second screw passed through the second through hole is inserted,
The communication device according to claim 1 , wherein when the second screw is fastened in the screw hole, the first conductor is electrically connected to the box body via the second screw. a substrate on which the first conductor and the second conductor are disposed;
The device connector has a conductive rod having electrical conductivity,
The communication device according to claim 1 , wherein the substrate is provided with an insertion hole into which the conductive rod is inserted. A communication device that receives a differential signal represented by a voltage difference between two electrical signals propagating through two conductors, respectively;
a vehicle power supply device to which the communication device is attached and which supplies power to the communication device;
The communication device includes:
a noise removal circuit that removes noise from the two electrical signals using the potential of the first conductor as a reference potential;
a signal conversion unit that converts a differential signal represented by a voltage difference between the two electrical signals from which noise has been removed by the noise removal circuit into a voltage signal represented by a voltage whose reference potential is the potential of the second conductor;
and a device connector connected to the power supply device,
the power supply device includes a power supply circuit that supplies power to the signal conversion unit by applying a voltage, the reference potential of which is the potential of the second conductor, to the signal conversion unit via the device connector;
The communication device transmits data included in the voltage signal converted by the signal conversion unit to the power supply device via the device connector.
Communications equipment. A communication device that receives a differential signal represented by a voltage difference between two electrical signals propagating through two conductors, respectively;
a vehicle power supply device to which the communication device is attached and which supplies power to the communication device;
Equipped with
The communication device includes:
a noise removal circuit that removes noise from the two electrical signals using the potential of the first conductor as a reference potential;
a signal conversion unit that converts a differential signal represented by a voltage difference between the two electrical signals from which noise has been removed by the noise removal circuit into a voltage signal represented by a voltage whose reference potential is the potential of the second conductor;
a device connector connected to the power supply device;
having
The power supply device is
An equipment connector connected to the device connector;
a main conductor having the same potential as the second conductor and connected to the device connector;
a power supply circuit that supplies power to the signal conversion unit by applying a voltage whose reference potential is the same as the potential of the second conductor to the signal conversion unit via the equipment connector and the device connector;
have
Communications equipment. The power supply has a power conductor;
The power supply circuit of the power supply device applies a voltage, the reference potential of which is the potential of the power supply conductor, to the signal conversion unit via the device connector;
The second conductor is connected to the power conductor via the device connector.
A communication device according to claim 16 or 17 . The power supply device is
A second power conductor;
a voltage conversion unit that converts a voltage whose reference potential is the potential of the second power supply conductor into a voltage whose reference potential is the potential of the power supply conductor;
The communications device of claim 18 , wherein the first conductor is connected to the second power conductor via the device connection. the power supply device having a power conductor and a second power conductor;
the power conductor and the second power conductor are connected to the second conductor and the first conductor, respectively;
The communication device according to claim 16 , wherein the power supply conductor and the second power supply conductor are connected by an inductor, a resistor or a second conducting wire. The communication device according to claim 16 , wherein the communication unit transmits data included in the voltage signal converted by the signal conversion unit to the power supply device via the device connector.

Images