JPH0613295B2 - Steering switch device - Google Patents

Description

The present invention relates to a steering switch device that transmits a large number of switch signals from a steering wheel.

[Prior Art] As a conventional steering switch device, for example,
There is something like the one shown in the figure.

In FIG. 4, reference numeral 1000 denotes a steering switch circuit provided on the steering wheel, and the steering switch circuit 1000 is a horn switch 1010.
And a switch 1020 for ASCD. The switch 1020 for ASCD is a CANCEL switch 1021, RE.
S / ACCEL switch 1022 and SET
/ COAST (deceleration) switch 1023. 10
Reference numerals 30 to 1050 denote sliding-type conductive contacts (hereinafter referred to as sliding contacts) provided on the boundary between the steering wheel and the steering column, which are composed of a slip ring and a contact piece. The sliding contacts 1030 are for power supply and sliding. Moving contact 1
040 and 1050 are for transmitting the ASCD switch signal. The sliding contact 1040, 1050 has a signal line 104
1, 1051 are respectively connected, and the signal lines 1041, 1
051 is pulled down with a high resistance in the ASCD control unit 4000. 2000 is a horn relay connected to battery power source B, 3000
Is a horn.

Therefore, when the RES / ACCEL switch 1022 is turned on, the current is changed from the battery power source B to the exciting coil of the horn relay 2000 to the sliding contact 1030 to the RES / A.
CCEL switch 1022 → sliding contact 1040 → ASC
It flows through the pull-down resistor in the D control unit 4000, and one of the two inputs of the ASCD control unit 4000 changes from the “L” level (= ground voltage) to the “H” level (= power supply voltage) and the signal is transmitted. It Similarly, set / coast the switch 1023 to 0.
If it is N, a current flows through the sliding contact 1050, and the CANCEL
When the switch 1021 is turned on, current flows through both the sliding contacts 1040 and 1050 via the diodes D1 and D2.

As described above, the three types of ASCD switch signals on the steering can be sent via the two sliding contacts 1040 and 1050. Since each of the above currents is very small (for example, several + mA to several mA) and is sufficiently smaller than the operating excitation current (for example, several hundreds mA) of the horn relay 2000,
Relay 2000 does not operate to drive horn 3000.

On the other hand, when the horn switch 1010 is turned on, the exciting coil of the horn relay 2000 turns on the horn switch 1010.
Is directly grounded and all power supply voltage is applied,
A sufficient current exceeding the relay actuation excitation current flows to actuate the relay 2000 to drive and blow the horn 3000. When the horn switch 1010 is ON, the voltage of the sliding contact 1030 is at the ground level, that is, "L".
Since it is a level, at this time, at the same time, the ASCD switch 1
Even if any of 020 is turned on, the switch output remains at the "L" level and the signal cannot be transmitted.
That is, the horn switch 1010 has priority. (See Japanese Patent Laid-Open No. 61-94850) With the switch circuit configuration as described above, about 3 to 4 types of switch transmission can be surely performed, but recently, radio switches and air conditioner switches are also transmitted from the steering. Demands have arisen, and a method of increasing the number of the sliding contacts 1030 to 1050 and transmitting signals in a contactless manner by optical communication has been adopted. FIG. 5 shows an example of transmitting a radio switch signal by optical communication.

In FIG. 5, reference numeral 1061 denotes the device on / off and channel selection,
Radio switches for controlling the volume, and the ON / OFF signals of the radio switches 1061 are transmitted by the transmission circuit 106.
Input to 0. The transmission circuit 1060 is for performing time division multiplex communication of these signals, and the optical ring 1070
Transmission is performed via the light emitting diode 1071 embedded therein. Reference numeral 1080 denotes a receiver-side amplifier that receives an optical signal from the light-emitting diode 1071.
Reference numeral 080 is a light receiving diode 1081 and an amplification circuit 1082.
And have. The output signal of the amplifier 1080 is input to the receiving circuit 5000, which receives the signal 501 corresponding to the ON / OFF signal of the radio switches 1061.
Outputs 0.

Therefore, the transmission circuit 1060 is connected to the radio switch 106.
When any one of 1 is turned on, signal reception as shown in FIG. 6 is performed. That is, the radio switches 1061 are respectively provided with the corresponding “0” and “1” code codes in advance. When the existing switch 1061 is turned on, the transmission circuit 1061 causes the light emitting diode 1071 to blink, The code corresponding to switch 1061 is transmitted as follows.

First, the start marker 100 is generated to start the transmission. Next, "0" is distinguished by the short pulse 200 and "1" by the long pulse 300, and the predetermined codes are sequentially output. And this is switch 106
After 1 is turned on, it is repeated several times periodically. Thus, the signal is input to the photodiode 1081 via the light emitting diode 1071, converted again into an electric signal by the amplification circuit 1082, and output to the reception circuit 5000. Each time the receiving circuit 5000 detects the start marker 100, it decodes the subsequent code code and outputs a corresponding signal 5010.

As described above, a large number of switch signals can be transmitted on the steering wheel by adding the circuit configuration below the dotted line in FIG. In such a communication method, a new signal transmission path is created by adding the optical ring 1070 and the like without changing or adding the existing sliding contacts 1031 to 1050, which is excellent in specifications compatibility and reliability. There is.

[Problems to be Solved by the Invention] However, in such a conventional steering switch device, in order to transmit a large number of switch signals, it is necessary to increase the number of sliding contacts for signal transmission, Alternatively, since optical communication is performed by adding a light ring, the number of contacts is limited in the space around the steering shaft in the case of the method of increasing the number of sliding contacts, so four contacts and five contacts are used. However, if the contact density is increased and the contact density is increased, the contact width must be reduced and the structure must be changed. In this case, the parts cannot be shared and the contact reliability is deteriorated. In addition, a special material is required to ensure reliability with the contact width kept narrow, which causes a problem of cost increase.

In addition, in the case of the method of adding the optical ring and the like, it is not necessary to change the sliding contact, but the additional optical ring increases the cost of the transmission line, and the electric-optical converter and the opto-electric converter are also added. Is indispensable, and there is a problem in that they cause cost up.

[Means for Solving Problems] The present invention has been made by paying attention to such conventional problems, and one of the existing sliding contacts is commonly used as a transmission line for time division multiplex communication. By adding an asymmetrical charging / discharging circuit to the receiving side, it is possible to reliably transmit a large number of switch signals at low cost by discriminating between the transmission signal via the sliding contact and the time division multiplexed signal. It is an object of the present invention to provide a steering switch device that operates.

In order to achieve this object, the present invention comprises a plurality of first switches provided on a steering wheel of a vehicle,
Turning on the first switch based on the voltage level of the on / off signal transmitted through the plurality of sliding conductive contacts formed on the boundary between the steering wheel and the steering column, A switch input determination circuit for determining OFF, a plurality of second switches provided on the steering wheel of the vehicle, and a ON / OFF signal of the second switch provided on the steering wheel side and modulated to a time-series pulse signal. And a time division multiplex transmission circuit for transmitting a multiplexed signal, a time division multiplex reception circuit provided on the steering column side for demodulating a multiplexed signal input through a part of the sliding type conductive contact, and a steering wheel. It is provided on the column side and is connected to a part of the sliding type conductive contact, and the input signal is the voltage level signal by the first switch or the second level switch. A signal discriminating circuit which discriminates whether the signal is a time-series pulse signal generated by the switch, and when it is the signal of the first switch, outputs a voltage level signal equivalent to the input signal to the switch input discriminating circuit. .

[Operation] In the present invention having such a configuration, the multiplex communication signal of the radio switch and the switch signal of the ASCD are discriminated by the asymmetric charge / discharge circuit. That is, ASCD
When the switch signal is input, the asymmetrical charging / discharging circuit outputs “H” level, and the signal is transmitted at this voltage level. When the signal with the radio switch is input, it is “H” level output. Instead, normal multiplex communication is performed. In this way, a large number of switch signals can be transmitted easily and reliably. Further, since it is only necessary to add the asymmetrical charging / discharging circuit, it is not necessary to change the configuration of the conventional switch circuit, and the photoelectric ring, the photoelectric converter, etc. are not required, so that the cost can be reduced.

[Embodiment] Hereinafter, the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of the present invention. In addition,
The same components as those of the conventional example are designated by the same reference numerals, and the description thereof will be omitted.

First, the configuration will be described. In FIG. 1, reference numeral 1160 is a transmission circuit for performing time division multiplex communication. In the communication circuit 1060 of the conventional example, light is turned on and off, but the transmission circuit 1160 is "H". Alternatively, transmission is performed at a voltage level of "L"("H" = power supply voltage level, "L" = ground level). The transmission circuit 1160 uses the SET / C of the ASCD switch 1020 as its output transmission path.
OAST and CANSEL switches 1022, 1
The sliding contact 1050, which serves as a signal transmission line of 023, is shared and is wired in the steering 1100 in a circuit manner. Reference numeral 5100 is a receiving circuit.
Is a time division multiplex reception circuit 5110 and a signal discrimination circuit 512.
It is composed of 0 and. The signal input via the signal line 1051 connected to the sliding contact 1050 is directly AS
Without entering the CD Control Unit 4000
Once input to the receiving circuit 5100, the output signal of the signal discriminating circuit 5120 is sent to the ASCD via the signal line 1052.
Control unit (switch input discrimination circuit) 40
00 is input. The transmission circuit 1160 and the time division multiplex circuit 5110 perform transmission / reception at a voltage level of "H" or "L" through the sliding contact 1050, and the data format or the like is received by the transmission circuit 1060. Circuit 5
It is the same as the relationship with 000. (See FIG. 6).

Next, the signal discrimination circuit 5120 will be described with reference to FIG. In FIG. 2, reference numerals 5121 and 5123 denote P-channel MOS.FETs, which constitute a so-called mirror circuit having a common gate and a symmetrical shape.
A high resistance (about 1 MΩ) 5122 that narrows down the current is connected to one of the MOS / SET 5121 sides. 5124
Is an inverter for inverting the input signal, 5125 is a capacitor (about 5PF) for charging the supply current to the other MOS • SET 5123, and the capacitor 5125 is charged between these inverters 5124 and 5125. N- for discharging
A channel MOS • FET 5126 is interposed. 5
127 is an output buffer, and Vt is set as the input threshold Vth.
It is set so that h = 1/2 VDD. Further, the ratio W / L of the gate width = W and the gate length = L of one of the MOS • FETs 5121 is set to P1 = W1 / L1 and the other MO.
When the W / L of the S-FET 5123 is P2 = W2 / L2, P1: P2 is set to be 8000: 1. Here, when the voltage VDD is VDD = VBV,
Next, consider the condition that the buffer 5127 becomes the output of "H" level. First, when the level of the input (IN) signal is "H" level, the inverter 5124 is at "L" level, so the N-channel MOS • SET 5126 is in a non-conductive state. Also, one of the MOS FET
5121 is always connected to i1 = VBV / due to the high resistance 5122.
A current of 1 MΩ = VBμA is flowing. On the other hand, P1: P
2 is 8000: 1, N-channel MOS ・ FET
Since 5126 is OFF, the capacitor 5125 is The current flows in and the battery is charged. Therefore, the time τ until the charging voltage of the capacitor 5125 becomes VDD / 2 = VB / 2V is Becomes That is, the input signal “H” level is τ = 10 m
The output of the buffer 5127 becomes the "H" level for the first time after continuing for more than sec. Next, when the input signal (IN) level is “L” level, the inverter 5124 becomes “H” level and the N-channel MOS • FET 5126 becomes conductive, so that the charge accumulated in the capacitor 5125 is immediately discharged, The output of the buffer 5127 becomes "L" level. As described above, the signal discrimination circuit 5120 performs charging with the time constant τ when the input signal is at “H” level,
At the "L" level, an asymmetric charge / discharge circuit that rapidly discharges is configured. It should be noted that such a circuit can be easily configured internally by forming it into an IC together with the time division multiplex reception circuit 5110.

Here, the signal determination circuit 5120 is an asymmetrical charging circuit,
The reason for setting the time constant on the discharge side to almost 0 is as follows.

First, it is the simplest and surest way to judge whether it is a multiplexed data signal or an ASCD switch signal depending on whether it is a pulse input or a continuous input. In this case, "H""It is equivalent to discriminating on the level time length. Therefore, it can be determined by measuring the "H" level length. One of the circuit configurations that most efficiently realizes this function is the asymmetrical charging / discharging circuit of this embodiment.

By the way, when a normally used symmetrical charging / discharging circuit, that is, a simple low-pass filter is used, it takes time to discharge, and therefore, a signal such as a multiple data signal in which pulses are continuous and an ASCD switch or the like are used. Discrimination from a continuous signal has the following difficulties. That is, since the low-pass filter outputs the input integrated value, even if the pulse width (“H” level width) of the multiplex data signal is sufficiently short, the output value is large if the duty is large, that is, the pulse interval is short. It approaches "H" level endlessly.
Therefore, in the multiplex data signal, it is necessary to keep the pulse interval sufficiently long to keep the duty sufficiently low (for example, 10% or less), so that the data transmission efficiency is extremely lowered.
However, considering the instantaneous noise of the sliding contact 1050, etc., the “H” level pulse width is too short, for example, 1
Since it cannot be set to 0 μsec or less, when considering it in combination with keeping the duty low, the data channel (1
Since the channel length is very long (for example, if the "H" level is 1 msec, the length of one data channel is 20 msec at a duty of 5%). 1
The time required for one communication = several hundred msec or more, resulting in a delay in response, which is not preferable.

Therefore, in this embodiment, for example, in the multiplex communication, the "H" level width of the smart marker 100 is set to 6 mse.
c, the "H" level width of data "0" is 1 msec, the "H" level width of data "1" is 3 msec, and the data channel length is 6 msec, and the "H" level width of the ASCA switch signal is 10 msec. That is all.

Next, the operation will be described based on the timing chart shown in FIG. First, the operation when the time t is t <t1 will be explained. Either of the radio switches 1061 becomes O.
Then, normal multiplex communication is performed as shown in FIG. 6 or FIG. 3a, and the radio switch 1061 is turned on,
Off, signal is transmitted. At this time, the start marker 10 is placed on the capacitor 5125 of the asymmetrical charging / discharging circuit 5120.
A current of i2 = VB / 8000 μA flows in each time 0 or a “H” level pulse of data 300 is input, and the input voltage level of the output buffer 5127 increases linearly as shown in FIG. 3b. But "H" level width is 10m
Since there is nothing that exceeds sec (maximum 6 msec of the start marker 166), when the pulse signal returns to the “L” level, it is immediately discharged and the output of the buffer 5127 is “H”.
It never reaches the level. In this way, the on / off signal of the radio switch 1061 is reliably transmitted.

Next, the operation when the time t is tt1 will be described. For example, at time t = t1, S of the ASCD switch 1020
ET / COAST or CANCEL switch 102
3, 1021, push the sliding contact 1050, the signal line 10
The voltage level input via 51 is forcibly set to the “H” level. Then, thereafter, the "H" level is maintained until the switch operation is completed. Therefore, after the start of operation τ
The output buffer 5127 outputs an "H" level signal at a time point t = t2, which is cut off by 10 msec (FIG. 3, C).
See waveform 500).

As described above, the multiplexed signal of the radio switch and the ASCD
It is possible to easily and reliably distinguish the switch signal from the switch signal. In this case, the ASCD switch signal has priority over the radio switch signal. Further, in this embodiment, only the radio switch is handled, but it is obvious that the same transmission can be performed even if the N switch and other switches are increased. In addition, only one of the two transmission lines 1040 and 1050 is used for communication, and the opposite operation is performed.
ES / ACCEL switch 1022 and SET /
COAST (deceleration) switch 1023 and the transmission line 10
40 and 1050 respectively correspond to the receiving circuit 5
When 100 is broken and fixed to "L" level or fixed to "H" level, the ASCD system does not operate, or even if it operates, the RES / ACCEL switch 1022
Can be canceled with or CANCEL switch 1021,
In addition, since there is no possibility that the two switches that are the reverse operations will be received in reverse, the ASCD switch 1
The reliability of the operation of 020 can be sufficiently ensured.

[Effects of the Invention] As described above, according to the present invention, an existing sliding contact is shared as one transmission line for time-division multiplex communication, and an asymmetric charging / discharging circuit is added to the receiving side. Since the signal transmitted through the sliding contact and the time-division multiplexed signal are discriminated, the ON / OFF signals of the ASCD switch and the radio switch can be easily and reliably transmitted, which is reliable. The property can be further improved. Moreover, since the ASCD switch path can be shared without changing, and the optical ring and the electrical-optical converter used in the conventional optical communication are not required,
The cost can be greatly reduced.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, FIG. 2 is an internal circuit diagram of the signal discriminating circuit thereof, FIGS. 3a to 3c are timing charts for explaining the operation, and FIG. FIG. 5 is a circuit configuration diagram of the ASCD switch circuit, FIG. 5 is a circuit configuration diagram of a conventional Leopard circuit, and FIG. 6 is a waveform diagram for explaining time division multiplex communication. 1020 ... ASCD switch (first switch) 1030 to 1050 ... Sliding conductive contact, 1061 ... Radio switch, (second switch) 1100 ... Steering wheel, 1160 ... Time division multiplex transmission circuit, 4000 ...... Switch input discrimination circuit, 5110 …… Time division multiplex reception circuit, 5210 …… Signal discrimination circuit.

Claims (2)

[Claims] 1. A first switch which is provided on a steering wheel of a vehicle, and a first switch which is transmitted through a plurality of sliding conductive contacts formed at a boundary between the steering wheel and a steering column. ON of the first switch based on the voltage level of the ON and OFF signals of
A switch input determination circuit for determining OFF, a plurality of second switches provided on the steering wheel of the vehicle, and a ON / OFF signal of the second switch provided on the steering wheel side and modulated to a time-series pulse signal. And a time division multiplex transmission circuit for transmitting a multiplexed signal, a time division multiplex reception circuit provided on the steering column side for demodulating a multiplexed signal input via a part of the sliding type conductive contact, and a steering wheel. It is provided on the column side and connected to a part of the sliding conductive contact, and determines whether the input signal is a voltage level signal by the first switch or a time series pulse signal by the second switch, And a signal discriminating circuit that outputs a voltage level signal equivalent to the input signal to the switch input discriminating circuit when the signal is the first switch signal. Steering Sui Tutsi apparatus according to symptoms. 2. The signal discrimination circuit performs the discrimination by measuring a high level time length or a low level time length of the voltage level of the input signal, and the discrimination of the time length is performed at the high level of the input signal. Alternatively, the steering according to claim 1 is characterized in that the charging is performed at a low level with a predetermined time constant, and the charging is performed using an asymmetrical charge / discharge circuit that performs rapid discharge at a low level or a high level. Switch device.