JP2007076621A - Tire air pressure monitoring system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify a mechanism for receiving a radio signal transmitted from a tire sensor provided on a tire side in a tire air pressure monitoring system. <P>SOLUTION: A tire information receiving module 23 for radio-receiving a detection signal from the tire sensor attached to the tire is arranged at a position, close to a wheel speed sensor module 21 arranged on a tire house, where a shielding material is not interposed between the tire sensor 24 and it. A branch wire form a power source wire 41 connected to the wheel speed sensor module 21 is connected to the tire information receiving module 23. The tire information receiving module 23 is provided with a substrate formed with a pattern antenna and the detection signal from the tire sensor is received by the pattern antenna. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a tire pressure monitoring system, and more specifically, includes a tire information receiving module that wirelessly receives a detection signal from a tire sensor that detects the air pressure of a pneumatic tire.

  Recently, a transmitter including a tire sensor that detects the air pressure of a pneumatic tire and a transmitter that wirelessly transmits a detection signal of the tire sensor is provided in a tire valve or the like, and the wireless signal from the transmitter is provided on the vehicle body side. A tire pressure monitoring system (TPMS: Tire Pressure Monitoring System) that acquires tire pressure information by receiving with an antenna element of a fixed receiver is provided in Japanese Patent Laid-Open No. 2005-55319 (Patent Document 1) and the like. Yes.

In Patent Document 1, as shown in FIGS. 4A and 4B, a wheel unit 4 having a pneumatic sensor 2 and a transmitter 3 is mounted in a tire 1, while a receiving unit 5 is mounted in a vehicle compartment on the vehicle body side. And is configured to receive a radio signal from the transmitter 3 on the tire 1 side via an antenna 6 connected to the receiving unit 5.
The antenna 6 is wound in the form of a coil around a harness 9 that connects a wheel speed sensor 7 and a wheel speed ECU 8 that are mounted in the vicinity of the axle end of the tire 1 or in the vicinity of a brake disk. The antenna 6 is connected via a harness cable 10. To the receiving unit 5.

  The antenna 6 is coiled so that the radio frequency transmitted from a tire equipped with a tire sensor (TPMS) is a sensor signal in the 300 MHz band, the wavelength of the 300 MHz band is about 1 m, and the antenna 6 is connected to the antenna. If the quarter-wave monopole antenna having the basic structure is used, the length of the antenna 6 needs to be about 25 cm. In order to reduce the size of the antenna 6, it is wound around the harness 9 as a coil shape as described above.

The mounting position of the antenna 6 is usually on the side of the passenger compartment near the tire case for weather resistance and the like, but if it is attached on the passenger compartment side, the metal body chassis may become a radio wave shield. high. Therefore, in Patent Document 1, the antenna 6 is wound around the harness 9 in the vicinity of the axle end portion or in the vicinity of the brake disk. Therefore, as the harness 10 that connects the receiving unit 5 and the antenna 6, the weather resistance is expensive. It is necessary to use a bridging harness having a power line and an expensive coaxial line (coaxial cable) as a signal line for transmitting a high-frequency signal.
The coaxial line includes a central conductor, an insulating coating in which the central conductor is covered with an insulating material made of a material having a low dielectric loss tangent and low high-frequency loss, and a shielding conductor made of a metal braid or the like that covers the outer peripheral surface of the insulating coating. And a protective insulation coating that covers the outer peripheral surface of the shield conductor. In this way, because of the multi-layer structure, it is not easy to route to the brake near the axle end or the brake disc near the axle end, which is difficult to route due to poor flexibility, is difficult to route, and coaxial cable There are also expensive problems.

JP 2005-55319 A

  The present invention has been made in view of the above problems, and it is an object of the present invention to reduce the number of power sources composed of expensive bridging harnesses and to eliminate signal lines using expensive coaxial cables that are difficult to route.

In order to solve the above-described problems, the present invention provides a tire information receiving module that wirelessly receives a detection signal from a tire sensor mounted on a pneumatic tire, close to an ABS / wheel speed sensor module disposed in a tire house. Arranged at a position not interposing a shielding material between the tire sensor,
Connecting a branch line from a power line connected to the ABS / wheel speed sensor module to the tire information receiving module to share the power line; and
The tire information receiving module includes a substrate on which a pattern antenna is formed, receives a detection signal from the tire sensor with the pattern antenna, and includes a demodulation unit for the detection signal received with the pattern antenna, the demodulation unit The tire information monitoring system is characterized in that the tire information signal demodulated in (1) is superimposed on the power line and transmitted.

As described above, in the present invention, there is provided a tire information receiving module in which a pattern antenna for wirelessly receiving a detection signal from a tire sensor is formed on a substrate, the module is miniaturized, and ABS / wheel speed disposed in a tire house is reduced. The sensor module can be mounted at a position close to the sensor module and without a radio wave shielding object such as a metal chassis between the sensor module and the tire sensor.
In this way, by arranging the tire information receiving module close to the ABS / wheel speed sensor module, the power line connected to the ABS / wheel speed sensor module and the power line of the tire information receiving module can be shared, One power line using an expensive bridging harness can be integrated.
In addition, since the detection signal received by the pattern antenna of the tire information receiving module is transmitted by being superimposed on the power line, it is possible to eliminate expensive and undesired coaxial lines for signal lines, and to improve the routing workability. It can be improved dramatically.

  In addition, receiving the antenna as a pattern antenna on the substrate of the small tire information receiving module may slightly reduce the sensitivity of receiving from the tire sensor. However, in the present invention, since the antenna is disposed at a position where no radio wave shielding object exists between the tire sensor, that is, at a position within the line of sight of the tire sensor and at the line of sight, the antenna is disposed at a position close to the tire sensor. Does not decrease. That is, the radio wave transmitted from the tire sensor is attenuated in proportion to the square of the distance, but since the distance is close, the attenuation can be greatly reduced, and the reception sensitivity can be increased accordingly.

The shield between the tire information receiving module and the tire sensor is made of a metal body chassis or the like.
As the tire sensor, a TPMS sensor (tire pressure / temperature measurement sensor) or the like is used.

A tire information signal is superimposed on the power line from the tire information receiving module and transmitted to the ABS / wheel speed sensor ECU, and is transmitted to the four wheels via an in-vehicle LAN network connected to the ABS / wheel speed sensor ECU. It is preferable that a detection signal from the tire information receiving module disposed respectively is transmitted to the tire sensor ECU.
With this configuration, the tire sensor ECU can monitor four tire information signals collectively with a simplified wiring structure.

It is preferable to provide a band elimination filter at the power receiving end of the tire information receiving module and the ABS / wheel speed sensor module connected to the power line.
By providing the band elimination filter circuit, it is easy to pass signals and power to be handled, while noises other than signals and power to be handled can be released.

Waveform shaping means for extracting a detection signal from the tire sensor superimposed on the power supply line from the power supply line; and LAN control means for inputting and outputting the detection signal from the tire sensor extracted by the waveform shaping means to the in-vehicle LAN network. Prepared and
The tire sensor ECU uses a LAN control means for receiving a detection signal from the tire sensor output from the ABS / wheel speed sensor ECU on the in-vehicle LAN, and a detection signal from the tire sensor received by the LAN control means. It is preferable to include processing means for monitoring the tire condition.

With the above configuration, the tire information digitized using the waveform shaping means (comparator) can be output to the in-vehicle LAN, and can be processed intensively by the processing means (tire sensor ECU). Further, by connecting an instrument panel display unit or the like to the processing means, it is possible to notify the driver that an abnormality in tire air pressure has occurred.
CAN, LIN, and BEAN can be adopted as the LAN network.

  The waveform shaping means can be composed of a capacitor that removes the DC component and a comparator that binarizes the tire information signal from which the DC component has been removed by the capacitor.

  As described above, according to the present invention, the tire information receiving module including the substrate provided with the pattern antenna is disposed in proximity to the ABS / wheel speed sensor attached to the tire house, so that the power line to the tire information receiving module is provided. Can be shared with the power line for the ABS / wheel speed sensor, and the signal line itself for outputting the tire information signal can be abolished by transmitting the reception signal from the tire information receiving module superimposed on the power line. As a result, it is possible to abolish the power supply line consisting of an expensive bridge harness and an expensive signal line coaxial cable to be connected to the tire information receiving module, and it is possible to reduce the cost by reducing the number of wirings, and there is a space limitation. In addition, there are various advantages such as improvement in wiring workability to a tire house that is difficult to wire.

  In addition, the wheel pressure sensor ECU provided for each of the front, rear, left, and right four wheels transmits the detected value from the wheel speed module and the tire pressure detected value from the tire information receiving module, and each wheel speed ECU is stretched around the vehicle. The vehicle wiring structure of the tire pressure monitoring system can be simplified by connecting to one tire sensor ECU.

Embodiments of the present invention will be described below with reference to FIGS.
As shown in FIG. 1, a tire information receiving module 23 (23A to 23D) is provided in a tire house 13 (13A to 13D) of four tires 11 (11A to 11D) on the front, rear, left and right sides of the automobile 10, respectively, while Tire sensors (TPMS sensors) 24 (24A to 24D) are attached to (11A to 11D), respectively, and detection signals detected by the tire sensors 24 are received by a pattern antenna formed on the substrate 25 of the tire information receiving module 23. It is configured.
The tire information receiving modules 23 </ b> A to 23 </ b> D are connected to each other via an in-vehicle LAN network 31 and a power line 32.

The wheel speed sensor modules 21A to 21D and the tire information receiving modules 23A to 23D mounted on the front, rear, left and right wheels respectively have the same configuration.
As shown in FIG. 2, in the tire house 13 where the tire information receiving module 23 is arranged, an ABS / wheel speed sensor module 21 (21A to 21D, hereinafter referred to as a wheel speed sensor) that measures the rotational speed of the axle 53 at a close position. Modules (abbreviated as modules 21A to 21D).

Specifically, in the tire house 13A, the wheel speed sensor module 21 and the tire information receiving module 23 are arranged in parallel on the outer surface of a bearing 54 that is connected to the axle 53, the upper arm 51, and the lower arm 52 to form a suspension. ing.
Since the bearing 54 is provided in the vicinity of the brake disk 12 provided at the end of the axle 53, the tire information receiving module 23 provided on the outer surface of the bearing 54 is close to the tire sensor 24 provided in the tire 11. Yes. In addition, the tire information receiving module 23 is located at a position where no shield such as a metal body chassis is interposed between the tire sensor 24 and the tire sensor 24.

  As shown in FIG. 3, the wheel speed sensor module 21 and the tire information receiving module 23 that are arranged close to each other are connected to a common power line 41, and the main power line 41a is connected to the wheel speed sensor module 21, and the main power line 41a is connected to the main power line 41a. A branch line 41 b from the power line 41 a is connected to the tire information receiving module 23. A bridge harness having weather resistance is used as the power supply line 41.

The wheel speed sensor module 21 includes a pickup unit 21-1 that detects the rotation speed of the axle 53 and outputs the rotation speed signal to the signal line 42, and the pickup unit 21-1 includes a band elimination filter circuit 21-. 3 is connected to the power supply line 41A.
The band elimination filter circuit 21-3 has a function of easily passing a signal in a target frequency band and releasing a signal in another frequency band. Since the DC power is supplied to the power line 41, The band elimination filter circuit 21-3 is designed to facilitate the passage of the DC power supply.

  On the other hand, the tire information receiving module 23 is provided on the substrate 25 with a pattern antenna 23-1 for receiving a radio signal including tire information transmitted from the tire sensor 24. Furthermore, the demodulator 23-2 that demodulates the radio signal received by the pattern antenna 23-1, and the tire information signal demodulated by the demodulator 23-2 are designed to be easily output to the branch line 41b. Band elimination filter circuit 23-3.

  The tire information signal output from the band elimination filter circuit 23-3 is superimposed on the power supply line 41, but only the frequency band of the tire information signal with less noise is supplied by the band elimination filter circuit 23-3. Since it can be superimposed on the line 41, the tire information signal and power can be prevented from interfering with each other.

  As described above, the tire information receiving module 23 is disposed close to the wheel speed sensor module 21, whereby the power line connected to the tire information receiving module 23 can be shared with the power line of the wheel speed sensor module 21. A dedicated power line connected only to the module 23 can be eliminated. Further, since the signal for transmitting the detection signal from the tire information receiving module 23 is superimposed on the power line 41, a coaxial line serving as a transmission line from the tire information receiving module can be eliminated.

The other end of the signal line 42 connected to the power line 41 and the wheel speed sensor module 21 is connected to an ABS / wheel speed ECU (hereinafter abbreviated as wheel speed ECU) 22 provided for each wheel.
The other end side of the power supply line 41 is connected to the DC power supply device 22-5 via a band elimination filter circuit 22-1 built in the wheel speed ECU 22, and is branched to a branch line 44.
As shown in FIG. 1, the DC power supply 22-5 is connected to a power supply line 32 to which a battery 62 mounted on the automobile 10 is connected.
On the branch line 44 side, waveform shaping means for extracting a tire information signal superimposed on the power supply line 41 is connected. The waveform shaping means includes a capacitor 22-6 that removes a DC component and a comparator 22-7 that separates and extracts the tire information signal superimposed on the power supply line 41 and binarizes it (digital signal). ing.

The output side of the comparator 22-7 is connected to the microcomputer 22-1, and the tire information signal binarized by the comparator 22-7 is input to the microcomputer 22-1, which is a control unit of the wheel speed ECU 22.
Further, the other end of the line 42 connected to the wheel speed sensor module 21 is also connected to the microcomputer 22-1, and the rotational speed signal detected by the wheel speed sensor module 21A is also input to the microcomputer 22-1.
Thus, the tire information signal transmitted from the tire information receiving module 23 and the rotational speed signal transmitted from the wheel speed sensor module 21 are input to the microcomputer 22-1.

The microcomputer 22-1 is connected in a CAN format to a CAN controller 22-2 which is a LAN control means for controlling communication by connecting to the in-vehicle LAN network 31 (the electric wires 31a and 31b shown in FIG. 1). The CAN controller 22-2 is connected to a CAN transceiver 22-3 that is an interface for connecting to the in-vehicle LAN network 31.
As described above, the wheel speed ECU 22 provided for each wheel outputs the tire information signal and the rotation speed signal processed by the microcomputer 22-1 to the in-vehicle LAN network 31 via the CAN controller 22-2 and the CAN transceiver 22-3. ing.
The in-vehicle LAN network 31 is composed of two electric wires 31a and 31b, and both ends thereof are connected by termination resistors 33a and 33b, thereby achieving impedance matching and suppressing signal reflection and attenuation inside the circuit. Yes.

The in-vehicle LAN network 31 is connected to one tire sensor ECU 61. The tire sensor ECU 61 acquires tire information signals output from the four-wheel wheel speed ECUs 22 (22A to 22D) to the in-vehicle LAN network 31, and centrally monitors the air pressures of the tires 11 (11A to 11D). Is going.
The tire sensor ECU 61 is connected to an instrument panel display unit (not shown), and when an abnormality (such as puncture) occurs in the tire air pressure, a display to that effect is displayed.

  The configuration in which the wheel speed ECU 22 provided for each of the four wheels is connected to a LAN network 31 extending around the vehicle may be an existing configuration. In this case, the existing LAN network 31 can be shared with the tire pressure monitoring system.

In the tire pressure monitoring system according to the present invention having the above-described configuration, first, the tire information receiving module that receives the radio signal from the tire sensor is disposed in the tire house adjacent to the wheel speed sensor module, thereby the wheel speed sensor. Can be shared with the module power line. In addition, by superimposing the detection signal from the tire information receiving module on the power line and transmitting it, the conventionally required coaxial line can be eliminated.
Furthermore, by transmitting a detection signal from the tire information receiving module to the wheel speed sensor ECU, the detection signal can be transmitted to the tire sensor ECU using a LAN network connected to the wheel speed sensor ECU. The transmission wiring mechanism for the tire air pressure detection signal from the receiving module can be simplified.

1 is an overall view of a tire pressure monitoring system according to the present invention. It is drawing which shows the arrangement | positioning state of the wheel speed sensor module and tire information receiving module in a tire house inside. It is the block diagram which showed the connection of a wheel speed sensor module, a tire information receiving module, and wheel speed ECU. It is drawing which shows a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Car 11 (11A-11D Tire 21 (21A-21D) Wheel speed sensor module 22 (22A-22D) Wheel speed ECU
23 (23A to 23D) Tire information receiving module 22-1 Microcomputer 22-2 CAN controller 22-3 CAN transceiver 22-6 Capacitor 22-7 Comparator

Claims (5)

A tire information receiving module that wirelessly receives a detection signal from a tire sensor mounted on a pneumatic tire is adjacent to an ABS / wheel speed sensor module disposed in a tire house, and a shielding material is interposed between the tire sensor and the tire sensor. Placed in a position where
Connecting a branch line from a power line connected to the ABS / wheel speed sensor module to the tire information receiving module to share the power line; and
The tire information receiving module includes a substrate on which a pattern antenna is formed, receives a detection signal from the tire sensor with the pattern antenna, and includes a demodulation unit for the detection signal received with the pattern antenna, the demodulation unit A tire pressure monitoring system, wherein the tire information signal demodulated in step 1 is superimposed on the power line and transmitted.   A tire information signal is superimposed on the power line from the tire information receiving module and transmitted to the ABS / wheel speed sensor ECU, and is transmitted to the four wheels via an in-vehicle LAN network connected to the ABS / wheel speed sensor ECU. 2. The tire pressure monitoring system according to claim 1, wherein the tire pressure monitoring system is configured to transmit detection signals from the tire information receiving modules respectively arranged to the tire sensor ECU.   The tire pressure monitoring system according to claim 1 or 2, wherein a band elimination filter is provided at a power receiving end of a tire information receiving module and an ABS / wheel speed sensor module connected to the power line. Waveform shaping means for extracting a detection signal from the tire sensor superimposed on the power supply line from the power supply line; and LAN control means for inputting and outputting the detection signal from the tire sensor extracted by the waveform shaping means to the in-vehicle LAN network. Prepared and
The tire sensor ECU uses a LAN control means for receiving a detection signal from the tire sensor output from the ABS / wheel speed sensor ECU on the in-vehicle LAN, and a detection signal from the tire sensor received by the LAN control means. The tire pressure monitoring system according to any one of claims 2 and 3, further comprising processing means for monitoring the tire condition.   5. The tire pressure monitoring system according to claim 4, wherein the waveform shaping means comprises a capacitor for removing a direct current component and a comparator for binarizing a tire information signal from which the direct current component has been removed by the capacitor.

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