JP4152240B2 - Wheel information acquisition system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention wirelessly transmits measurement data relating to wheels of various vehicles such as trucks, buses and passenger cars, such as vehicles having at least four wheels or two-wheeled vehicles, such as tire internal pressure data and tire temperature data, to the vehicle body. The present invention relates to a wheel information acquisition system for transmission.
[0002]
[Prior art]
Today, in tires such as trucks, buses, passenger cars, and even motorcycles with wheels that have tires assembled on the rim, a tire internal pressure alarm system that constantly monitors the internal pressure of tires and reports abnormalities in the internal pressure of tires in the event of an abnormality. It is proposed to be worn.
[0003]
In the tire internal pressure alarm system, for example, a pressure sensor that measures internal pressure in a hollow area of a tire that is filled with air surrounded by the inner peripheral surface of the tire and the bottom surface of the rim bottom, and internal pressure data measured by the pressure sensor. Is transmitted wirelessly. On the other hand, a receiver antenna for receiving tire internal pressure data is provided in the vicinity of the tire house of the vehicle body, and the internal pressure data is received by this antenna. The receiver always monitors whether or not the tire internal pressure is abnormal, and if abnormal, informs the driver that the internal pressure is abnormal.
[0004]
In this tire internal pressure alarm system, a transmitter for transmitting tire internal pressure data and temperature data is provided in the cavity region of the tire. Therefore, the transmitter cannot be maintained unless the rim and tire are separated. For this reason, in order for the transmitter to radiate radio waves for a long period of time and transmit the internal pressure data and temperature data, it is desired to refrain from consuming the battery used for the transmitter as much as possible.
[0005]
In Patent Document 1 below, a switch for monitoring the running state of the vehicle is provided. When the internal pressure is normal, the vehicle runs and the switch is activated, so that the tire pressure is set to 15 minutes by the pressure sensor. From the first state where the measurement data is measured and monitored every hour and the measurement data is transmitted every hour, the tire pressure is measured every 10 seconds by the pressure sensor, and the measurement data is transmitted every minute. Discloses a remote tire pressure monitoring system that can be switched.
Thereby, consumption of the battery of the transmitter can be suppressed.
[0006]
[Patent Document 1]
Japanese National Patent Publication No. 10-508264
[Problems to be solved by the invention]
Incidentally, since the transmitter of the system in Patent Document 1 transmits internal pressure data and temperature data over a long period of time, an error that was not expected at the design stage occurs in an IC that is a processing circuit provided in the transmitter. In some cases, the operation of the transmitter may be abnormal due to noise included in the measurement data. In the above system, the internal pressure data of the parked tire immediately before the start of vehicle travel is transmitted and monitored. This internal pressure data is the internal pressure data obtained in the first state transmitted every hour. It is not necessarily the internal pressure data immediately before the vehicle travels. For this reason, there has been a problem that the driver cannot perform a work inspection based on the tire internal pressure data immediately before the vehicle travels.
Further, when the tire internal pressure is within a preset allowable range and is in a normal state, it is still strongly desired to effectively monitor the tire internal pressure without consuming as much power as possible from the transmitter. .
[0008]
Therefore, in order to solve the above problems, the present invention provides a transmitter that wirelessly transmits measurement data measured by a measurement element such as a pressure sensor provided on a wheel mounted on a vehicle, and a transmitter that transmits the measurement data. Wheel information acquisition system having a receiver for receiving the measured measurement data, which consumes as little power as possible of the transmitter, can effectively monitor the internal pressure of the tire, and operates the transmitter It is an object of the present invention to provide a wheel information acquisition system that can immediately recover normal operation even when an abnormality occurs and that can monitor the state of the wheel based on measurement data immediately before the vehicle travels.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a first communication provided on the wheel, which includes a measurement element provided on a wheel, and processes and transmits measurement data measured by the measurement element wirelessly. A wheel information acquisition system comprising: a first communication device; and a second communication device provided in a vehicle main body mounted on the wheel for receiving measurement data transmitted from the first communication device. The communication device resets the circuit of the first communication device to an initial state including a sleep mode in which processing and transmission of the first communication device are suspended, and clearing the remaining measurement data. A measurement / transmission mode for transmitting measurement data measured by the measurement element to the second communication device, and the first communication device is connected to the scan device according to a reset signal generated by the first communication device. After switching to the measurement and transmission mode from Pumodo, it provides the wheel information acquiring system and returning to the sleep mode.
[0010]
Here, the second communicator is intermittently driven at a predetermined cycle, and the first communicator is longer than the drive cycle of the second communicator in the measurement / transmission mode, It is preferable to repeatedly transmit a transmission signal including measurement data.
The first communicator switches the mode according to at least one of a switching element that switches a mode according to the rotation of the wheel and a vibration or sound that is generated when the vehicle gets on and propagates to the wheel. It is preferable to switch to the measurement / transmission mode from the sleep mode and then return to the sleep mode.
[0011]
The measurement data is, for example, at least one of internal pressure data, temperature data, and measurement voltage data of a driving power source of the first communication device.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the wheel information acquisition system of the present invention will be described in detail based on a preferred embodiment shown in the accompanying drawings.
FIG. 1 shows a tire internal pressure monitoring system (hereinafter referred to as a system) 10 for a truck vehicle, which is an example of a wheel information acquisition system.
[0013]
Wheels 12 a to 12 f, which are tire and rim assemblies shown in FIG. 1, are mounted at each wheel mounting position of the truck vehicle 14.
In the hollow regions of the tires of the wheels 12a to 12f, transmitters (first communication devices) 16a to 16f that wirelessly transmit the measured internal pressure data and temperature data to the bottom surface of the rim that is the wall surface of this region. The transmitters 16a to 16f each have a pressure sensor and a temperature sensor.
[0014]
In the vicinity of the tire house at each mounting position on the vehicle body to which the wheels 12a to 12f of the truck vehicle 14 are mounted, receiver communication units 18a to 18a having antennas and amplifiers for receiving information transmitted wirelessly from the transmitters 16a to 16f. 18 f is provided, and the receiver communication units 18 a to 18 f are connected to one receiver body unit 20 by wire. Furthermore, the receiver body 20 is connected to a display 22 that displays internal pressure data to the driver of the truck vehicle 14. The receiver communication unit 18c is configured to receive transmission signals from the transmitters 16c and 16d, and the receiver communication unit 18f is configured to receive transmission signals from the transmitters 16e and 16f.
[0015]
The receiver communication units 18a to 18f and the receiver body unit 20 correspond to the second communication device in the present invention, and the receiver communication units 18a to 18b mainly receive measurement data such as internal pressure data and temperature data. Do.
[0016]
Since the transmitters 16b to 16f have the same configuration as the transmitter 16a, the transmitter 16a will be described as a representative of the transmitters 16a to 16f, and description of the transmitters 16b to 16f will be omitted. FIG. 2 is a schematic configuration diagram of the transmitter 16a.
The transmitter 16a includes circuits provided on the circuit board 24, a pressure sensor 26 that measures the internal pressure of the tire, a temperature sensor 27 that measures the temperature of the cavity region of the tire, and a vibration / sound sensor 29.
[0017]
The pressure sensor 26 is a semiconductor pressure sensor or a capacitive pressure sensor that measures gauge pressure, differential pressure, or absolute pressure, and measures the internal pressure of the tire. The temperature sensor 27 is a semiconductor temperature sensor or a resistance element type temperature sensor, and measures the temperature of the cavity region of the tire. The pressure sensor 26 and the temperature sensor 27 are connected to an AD conversion circuit 28 described later.
The vibration / sound sensor 29 is a sensor that senses vibration or sound propagating to the wheels and outputs a signal, and is connected to a switching circuit 37 described later. As an example of the vibration / sound sensor 29, a piezoelectric acceleration sensor is exemplified.
[0018]
The circuit board 24 includes an AD conversion circuit (AD) 28, a reset circuit 30, a microprocessor (MP) 32, a memory 34, a communication circuit 36, a switching circuit 37, a switching element 39, an antenna 40, and a battery as a power source for each circuit. 44 is provided.
The AD conversion circuit 28 is connected to the pressure sensor 26 and the temperature sensor 27, and converts the pressure signal measured by the pressure sensor 26 and the temperature signal measured by the temperature sensor into a digital signal such as 8-bit. is there.
[0019]
The reset circuit 30 generates a reset signal for resetting the transmitter 16a to an initial state, and when the tire internal pressure is normal (when the internal pressure is within a preset allowable range), the wheels 12a to 12f are extremely slow. In a rotational state exceeding a predetermined speed (for example, 10 km / hour) (hereinafter, this state is referred to as a dynamic state), for example, the internal pressure of the tire is intermittently measured every 10 seconds to monitor the internal pressure of the tire for a predetermined time. This is a part that manages the measurement time interval and the transmission time interval for repeatedly transmitting the internal pressure data and the temperature data from the antenna 40 toward the receiver communication unit 18a at intervals of, for example, one minute. The reset circuit 30 may be configured by a dedicated circuit or may be programmed in the MP32. When the AD converter circuit 28, the MP32 and the communication circuit 36 are always driven, a large driving power is required. Therefore, when the tire internal pressure is normal in the tire dynamic state, the AD converter circuit 28, the MP32 and the communication circuit 36 are driven at regular time intervals for measurement and transmission. The measurement / transmission mode to be performed is set, and the rest is set to the sleep mode in which processing and transmission of the transmitter 16a are suspended.
The reset signal generated by the reset circuit 30 is a signal for waking up the transmitter 16a in the sleep mode and switching to the measurement / transmission mode, and is generated at predetermined time intervals. Thereby, consumption of the battery 44 is reduced, and the transmitter 16a can monitor the internal pressure of the tire over a long period of time.
[0020]
It should be noted that the reset signal is generated at predetermined time intervals when the wheels 12a to 12f are stationary or are in a very low speed state (hereinafter referred to as a static state) equal to or lower than the predetermined low speed (for example, 10 km / hour). Then it switches to measurement / transmission mode. This time interval may be, for example, a time interval equivalent to the dynamic state or a longer time interval. Furthermore, a reset signal is not generated substantially once in the static state. It may be set not to switch to the transmission mode even once.
Of course, when the internal pressure of the tire is determined to be abnormal by monitoring, the time interval is changed short.
[0021]
The MP 32 receives the internal pressure data and the temperature data supplied after AD conversion in the AD conversion circuit 28, and the identification information (ID) of the transmitter 16a called from the memory 34 and distinguishable from the other transmitters 16b to 16f. ) And the word signal are used to generate a transmission signal to be transmitted to the receiver communication unit 18a and to process the supplied signal in accordance with a predetermined programmed process, and to control and manage the operation of each circuit It is.
The transmission signal generated by the MP32 is a signal in which a signal of a predetermined format is repeatedly generated. The ID or word signal is a signal in which 0 and 1 having a specific number of bits are continuously arranged according to a predetermined rule. The word signal is a signal in which, for example, a block in which 10 bits of 0 are arranged and then 10 bits of 1 are arranged is repeated 3 blocks.
In addition to storing and holding the ID of the transmitter 16a, the memory 34 can store measured internal pressure data and temperature data.
[0022]
The communication circuit 36 includes an oscillation circuit (not shown) that generates a carrier wave having a predetermined frequency, for example, 315 MHz, a modulation circuit (not shown) that generates a high-frequency signal obtained by modulating the carrier wave according to the transmission signal generated by the MP 32, and a high-frequency signal. And an amplifier circuit (not shown) for amplifying. Here, the carrier modulation method is an ASK (Amplitude shift keying) method, an FSK (Frequency shift keying) method, a PSK (Phase shift keying) method, a multi-value PSK method such as QPSK or 8-layer PSK, 16QAM, 64QAM, etc. Any known method such as a multi-value ASK method may be used.
[0023]
The switching circuit 37 is a circuit that operates in accordance with a signal output from the vibration / sound sensor 29 and switches a mode. The switching circuit 37 wakes up the sleep mode in which processing and transmission of the transmitter 16a are suspended and the MP 32 in the sleep mode. The mode is switched between the measurement / transmission mode for measuring and transmitting the transmitter 16a. The switching element 39 automatically detects the above-described dynamic state and static state of the wheel by the contact and non-contact of the contact by the centrifugal force acting on the transmitter 16a as the vehicle travels. It is an element that can.
[0024]
The antenna 40 is configured to radiate, for example, 315 MHz radio waves toward the receiver communication unit 18a and the setting device.
As the battery 44, for example, a known battery such as CR-2032 (coin-type manganese dioxide lithium battery) is used.
The above is the configuration of the transmitter 16a.
[0025]
FIG. 3 is a configuration diagram showing the receiver body 20 and the receiver communication units 18a, 18b,... Connected to the receiver body 20.
Since the receiver receivers 18a to 18f have the same configuration, the receiver communication unit 18a will be described as a representative.
The receiver communication unit 18 a includes an antenna 46 and an amplifier circuit 48. The antenna 46 is configured to receive, for example, 315 MHz radio waves transmitted from the transmitter 16a. The amplifier circuit 48 is configured using an FET (field effect transistor) or the like, amplifies the received high-frequency signal, and supplies the amplified high-frequency signal to the receiver body 20.
[0026]
The receiver main unit 20 demodulates the transmission signal from the high-frequency signals supplied from the receiver communication units 18a to 18f to extract internal pressure data, temperature data, and ID, and at which mounting position the transmitted internal pressure data and temperature data are located. It is the internal pressure and temperature of the tires of the mounted wheels, or is acquired from the taken-out ID using the association result preset and registered. The tire internal pressure is temperature-corrected according to the acquired mounting position information, and the tire internal pressure is monitored based on the temperature-corrected internal pressure data.
In the receiver main body 20, when high-frequency signals are supplied from the receiver communication units 18a to 18f, for example, by comparing the temperature-corrected internal pressure of the right front wheel tire with a predetermined set value, for example, “Normal ”,“ Caution ”, and“ Warning ”. The determination result is supplied to the display 22 connected to the receiver body 20. The indicator 22 displays the value of the internal pressure for each vehicle mounting position. Here, the display 22 displays the numerical value of the internal pressure and the determined state of the internal pressure on the instrument panel of the truck vehicle 14.
[0027]
The receiver main unit 20 includes demodulation circuits 52a to 52f, a timer circuit 54, an MP 56, a memory 58, and a signal processing circuit 59. The demodulating circuits 52a to 52f are circuits that perform a known filtering process and further perform code correction of the signal to generate a demodulated signal, and supply the demodulated signal to the MP 56.
[0028]
The timer circuit 54 is used to drive the MP 56, the demodulation circuits 52a to 52f, and the signal processing circuit 59 by switching the receiver main body 20 from the sleep mode to the drive mode at regular time intervals. Here, the cycle of the drive mode is, for example, 100 (msec), and the duration of the drive mode is, for example, 10 (msec). Since the period of such a driving mode is extremely long with respect to the period of the clock frequency of the MP 56, it can be configured using a low-frequency oscillator such as a CR circuit different from the MP 56 that generates the clock signal. For this reason, it is possible to suppress power consumption compared to the case of using the clock signal of the MP56. As the power source, a built-in battery (not shown) is used. Further, the battery of the truck vehicle 14 may be used as the power source.
[0029]
The MP 56 is switched between the sleep mode and the drive mode according to the timing of the timer circuit 54. The drive mode is maintained for a certain period of time at a predetermined cycle, for example, once every 100 (msec).
Further, when the receiver communication units 18a to 18f receive the transmission signals from the transmitters 16a to 16f in the drive mode, the MP 56 receives the ID and the internal pressure data from the signals supplied from the demodulation circuits 52a to 52f, and Information about the tire of which wheel the internal pressure data and the temperature data are based on the ID obtained by referring to the data obtained by acquiring the temperature data and referring to the association data between the ID set and stored in the memory 58 and the wheel mounting position information Find out if
The memory 58 stores and holds data for associating each ID of the transmitters 16a to 16f with the mounting position in the vehicle.
The signal processing circuit 59 is connected to the MP 56, and is a part that performs temperature correction of the internal pressure data using the temperature data and generates a signal suitable for the display device 50 from the temperature-corrected internal pressure data.
The receiver communication units 18a to 18f and the receiver body unit 20 are configured as described above.
[0030]
Next, operation | movement of the wheel information acquisition system 10 is demonstrated using the transmitter 16a among the transmitters 16a-16f.
When the truck vehicle 14 is parked and the wheel 12a is in the static state, the circuit of the transmitter 16a is reset to the initial state according to the reset signal generated by the transmitter 16a, and after this reset, the pressure sensor 26 and The internal pressure data and temperature data measured by the temperature sensor 27 are wirelessly transmitted to the receiver communication unit 18a. Of course, as described above, when the time interval in which the reset signal is generated in the static state is extremely long and the reset signal is not substantially generated, measurement and transmission are not performed.
[0031]
That is, when the transmitter 16a is awakened from the sleep mode in which the processing and transmission of the transmitter 16a are suspended, the transmitter 16a switches to the measurement / transmission mode. Furthermore, after switching to measurement / transmission mode, it returns to sleep mode again.
The reset signal is generated at a predetermined time interval in the transmitter 16a to clear data remaining in each circuit of the transmitter 16a. Thereafter, the latest internal pressure data and temperature data of the tire are acquired by measurement, and the internal pressure data and temperature data are transmitted as transmission signals to the receiver communication unit 18a. At this time, the duration of the measurement / transmission mode of the transmitter 16a that is switched from the sleep mode by the reset signal is equal to or longer than the period of the drive mode of the receiver 20, and the measured internal pressure data and temperature data are The included signal is repeatedly transmitted for a time longer than the period of the driving mode. 4A shows the period T ₁ of the driving mode of the receiver body 20, and FIG. 4B shows the transmission time T ₂ for repeatedly transmitting the transmission signal from the transmitter 16a. For example, if the period T ₁ of the driving mode of the receiver 20 is 100 (msec), the transmission time T ₂ in the measurement / transmission mode is 120 (msec), for example. A receiver that is intermittently driven by setting the transmission time T ₂ for repeatedly transmitting the transmission signal including the internal pressure data and the temperature data to be equal to or longer than the period T ₁ of the driving mode of the receiver body 20. The main body 20 can reliably receive the transmission signal.
[0032]
In the measurement / transmission mode, the circuit of the transmitter 16a is returned to the initial state before measuring the internal pressure and temperature of the tire, so that even if an abnormal operation of the transmitter occurs, the normal operation can be immediately recovered. In addition, consumption of the battery 44 of the transmitter 16a can be suppressed.
[0033]
Next, for example, when the door is opened and closed for the driver to get on the parked truck vehicle 14, the vibration / sound sensor 29 detects the vibration or sound at the time of opening and closing the door propagating through the wheel 12 a, and the signal is received. Is output. By this operation of the switching circuit 37, the transmitter 16a is switched from the sleep mode to the measurement / transmission mode similar to that described above. Also in this measurement / transmission mode, the transmission time for repeatedly transmitting the measured internal pressure data and temperature data is set to be equal to or longer than the period of the drive mode of the receiver body 20. Thereafter, the sleep mode is restored.
Thus, the tire internal pressure and temperature are measured in accordance with the ride of the driver. For this reason, when the instruments of the truck vehicle 14 are started, information on the internal pressure of the tire measured when the driver opens and closes the door is displayed on the display 22. That is, the latest information on the internal pressure of the tire immediately before the driver gets into the truck vehicle 14 and starts the engine is displayed, and the driver can easily perform the work inspection by looking at the display 22.
[0034]
Next, when the engine is started and the truck vehicle 14 is caused to travel, the wheel 12a senses the dynamic state by the operation of the switching element 39, and the sensed signal is supplied to the MP32. In MP32, at the time of shifting to this dynamic state, the operation of the switching element 39 switches from the sleep mode to the measurement / transmission mode, and returns to this sleep mode. That is, measurement and transmission at the time of transition to the dynamic state are performed. In the dynamic state, measurement and transmission are performed in accordance with a reset signal generated at a predetermined time interval by the transmitter 16a. For example, measurement / transmission for transmitting the latest tire internal pressure and temperature every minute. Switch to mode. Alternatively, when the wheel is in a dynamic state, the time interval at which the reset signal is generated may be shortened. As a result, the transmitter 16a can switch to the measurement / transmission mode in response to a reset signal generated at a short time interval.
Note that the sleep mode and the measurement / drive mode described above are modes in which the tire internal pressure is in a normal state, and measurement and transmission are performed in an extremely short time, of course, when the tire internal pressure is out of the preset allowable range. Therefore, the internal pressure of the tire will be strictly monitored.
[0035]
In the above embodiment, the tire internal pressure and temperature are measured and transmitted to the receiver as wheel information. Further, the transmitter battery voltage is measured, and this measurement data is transmitted to the receiver. It may be. Thereby, the lifetime of the transmitter can be known more accurately.
[0036]
As mentioned above, although the wheel information acquisition system of this invention was demonstrated in detail, this invention is not limited to the said Example, In the range which does not deviate from the summary of this invention, you may perform various improvement and a change. Of course.
[0037]
【The invention's effect】
As described above in detail, in the present invention, the transmitter is switched from the sleep mode to the measurement / transmission mode by the reset signal, the transmitter circuit is initialized by the reset signal, and then the tire internal pressure and the like are measured. Since data is acquired and transmitted, normal operation can be recovered immediately even if a transmitter malfunction occurs, and the tire pressure is effectively monitored without consuming as much transmitter power as possible. can do. In addition, measurement data such as tire internal pressure is obtained and transmitted using vibration and sound signals propagating through the wheels as triggers, so measurement of tire internal pressure etc. according to vibration and sound that occurs when the door of the driver entering the vehicle opens and closes Is done. Therefore, it is possible to monitor the state of the wheel immediately before the vehicle travels, and it is possible to effectively use the measurement data for the work inspection of the wheel.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an internal pressure information acquisition system which is an embodiment of a wheel information acquisition system of the present invention.
2 is a schematic configuration diagram of an example of a transmitter of the internal pressure information acquisition system shown in FIG. 1. FIG.
FIG. 3 is a schematic configuration diagram of an example of a receiver of the internal pressure information acquisition system shown in FIG. 1;
FIGS. 4A and 4B are diagrams for explaining the relationship between the period of a driving mode in a receiver and the transmission time of a transmission signal of a transmitter in the wheel information acquisition system of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Tire internal pressure monitoring system 12a-12f Wheel 14 Truck vehicles 16a-16f Transmitter 18a-18f Receiver communication part 20 Receiver main-body part 22 Display 24 Circuit board 26 Pressure sensor 27 Temperature sensor 28, 48 Amplifier circuit 29 Vibration / sound Sensor 30 Reset circuit 32, 56 Microprocessor 34, 58 Memory 36 Communication circuit 37 Switching circuit 39 Switching element 40, 46 Antenna 44 Battery 52a-52f Demodulation circuit 54 Timer circuit 59 Signal processing circuit

Claims (4)

A first communicator provided on the wheel, having a measuring element provided on the wheel, and processing and transmitting measurement data measured by the measuring element , and transmitted from the first communicator; A wheel information acquisition system having a second communicator provided on the vehicle body mounted on the wheel,
The first communicator resets the circuit of the first communicator to an initial state including a sleep mode in which processing and transmission of the first communicator are suspended, and clearing remaining measurement data. A measurement / transmission mode for transmitting measurement data measured by the measurement element after reset to the second communication device;
In accordance with a reset signal generated by the first communication device, the first communication device is switched from the sleep mode to the measurement / transmission mode and then returned to the sleep mode. The second communication device is intermittently driven at a predetermined cycle,
Wherein the first communication device, said at measurement and transmission mode, the second period longer than the drive cycle of the communication unit, vehicle information acquisition according to claim 1 for transmitting Shi repeat play a transmission signal including the measurement data system. The first communicator includes a switching element that switches a mode according to rotation of the wheel, and a switching that switches a mode according to at least one of vibration and sound that is generated when the vehicle gets on and propagates to the wheel. and an element, after switched from the sleep mode to the measurement and transmission mode by the switching element, the wheel information acquisition system according to claim 1 or 2 returns to the sleep mode. The said measurement data are at least any one of the internal pressure data of the tire of the said wheel, temperature data, and the measurement voltage data of the drive power supply of a said 1st communication device, The any one of Claims 1-3 . Wheel information acquisition system.

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