JP2006111158A - Tire air pressure detecting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tire air pressure detecting device avoiding radio interference among a vehicle body side transceiver and a plurality of wheel side transceivers, even if simultaneously imparting a trigger signal from an antenna on a vehicle body side to the the wheel side transceivers. <P>SOLUTION: A G sensor for detecting acceleration in the rotating direction of wheels is mounted on each of the wheel side transceivers. The G sensors are arranged so that the detection results at the time of traveling a vehicle may be mutually different in the two wheels of a plurality of wheels. In the vehicle side transceiver, a transmission-reception antenna is provided on the two wheels. When the wheel side transceivers receive the trigger signal from the transmission-reception antenna of the vehicle body side transceiver, control parts themselves of the wheel side transceivers are made to judge the rotating direction of the wheels according to the detection results of the G sensors, and to determine timing for transmitting a response signal to the vehicle body side transceiver according to the judgment results. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a tire air pressure detection device.

  Conventionally, there is a direct tire pressure detection device that performs two-way communication as one of tire pressure detection devices. This device is directly provided on a disc wheel of a wheel provided with a tire and a disc wheel, and is equipped with a wheel side transceiver equipped with a sensor such as a pressure sensor, and an antenna and a vehicle body side transmission / reception respectively provided in a wheel house on the vehicle body side. Machine.

  And in this apparatus, the sensing information by the above-mentioned sensor is transmitted to the body side transceiver from the wheel side transceiver by transmitting a trigger signal from the body side transceiver to the wheel side transceiver. In this way, the tire pressure is detected by the vehicle body side transceiver.

  Further, in the tire pressure detecting device described above, when a trigger signal is transmitted from a single vehicle body side antenna and a vehicle body side transceiver to a plurality of wheel side transceivers, a command for specifying a response wheel is inserted into the trigger signal. . That is, an ID is included in the trigger signal, ID authentication is performed by the wheel side transmitter / receiver, and only the wheel side transmitter / receiver with the matching ID is allowed to respond.

  In the tire pressure detecting device described above, an antenna as a trigger device that transmits a trigger signal is mounted at a position corresponding to each wheel such as a wheel house so that the trigger signal reaches only one wheel. In other words, the above-described device requires an antenna corresponding to each wheel.

  However, from the viewpoint of simplifying the apparatus, it is preferable that the number of antennas is small. Moreover, it is difficult to arrange an antenna corresponding to each wheel in a truck having a large number of wheels. This is because the trigger signal is transmitted to both tires even if it is attempted to transmit the trigger signal only to each of the so-called double tires of the truck or the like.

  Therefore, a method of reducing the number of antennas in the vehicle body side transceiver can be considered. That is, a trigger wave is transmitted simultaneously from one antenna to each transceiver mounted on a plurality of wheels.

  However, when there is a response from each wheel side transceiver to the vehicle body side transceiver at the same time, there is one antenna, so there is a problem that interference occurs and the response from each wheel side transceiver cannot be received. Arise.

  According to the method of including the ID in the trigger signal, even if the trigger signal is transmitted simultaneously from one antenna to each transceiver mounted on a plurality of wheels, Interference of responses can be avoided. However, in this method, when the position of the tire is changed by tire rotation or the like, it is necessary to re-register the ID for identifying the wheel, and the control for that is complicated, which is not preferable.

  In view of the above points, the present invention provides interference between a vehicle body side transceiver and a plurality of wheel side transceivers even if a trigger signal is simultaneously given from a single antenna on the vehicle body side to a plurality of wheel side transceivers. It is an object of the present invention to provide a tire air pressure detection device that can avoid the above-described problem.

  In order to achieve the above object, according to the first aspect of the present invention, the tire air pressure detecting device includes a wheel side transceiver and a vehicle body side transceiver.

  The wheel side transceiver 2 is provided in each of a plurality of wheels (5a to 5f) provided with tires, and outputs a detection signal corresponding to the air pressure of the tire provided in each of the plurality of wheels (5a to 5f). (21), the first control unit (23a) that processes the detection signal of the sensing unit (21), and the detection that is processed by the first control unit (23a) when the trigger signal transmitted from the vehicle body side is received. A first transmission / reception unit (23b) for transmitting a signal is provided.

  The vehicle body side transceiver 3 is provided on the vehicle body (6) side, transmits a trigger signal to the wheel side transceiver (2), and receives a detection signal, and a second transmission / reception unit (32a). The second control unit (32b) is provided for determining the tire air pressure provided to each of the plurality of wheels (5a to 5f) based on the detection signal. Moreover, the vehicle side transmitter / receiver (3) is provided with one transmitting / receiving antenna (31) for each of the two wheels (5a, 5b).

  The wheel-side transceiver (2) detects acceleration acting on the wheels (5a to 5f) when the wheels (5a to 5f) rotate, and outputs a detection result to the first control unit (23a). The acceleration sensor (20) includes two sensors (5a to 5f) so that detection results at the time of traveling of the vehicle are different from each other. Have been placed.

  Furthermore, when the first control unit (23a) receives the trigger signal, it determines the timing for transmitting the detection signal to the vehicle body side transceiver (3) based on the detection result of the acceleration sensor (20). It is characterized by that.

  As a result, when a trigger signal is simultaneously given from one antenna on the vehicle body side to the wheel side transceivers respectively mounted on the two wheels, these two wheel side transceivers themselves send response signals. The timing of sending each other can be shifted automatically.

  As a result, according to the present invention, it is possible to avoid interference between the two wheel side transceivers and the vehicle body side transceiver.

  In addition, in the description of claim 1, the arrangement of the wheel-side transmitter / receiver in two wheels so that the detection results at the time of traveling of the vehicle are different from each other means, for example, double tires on left and right wheels, trucks, etc. It means that the mounting positions of the wheel-side transceivers with respect to the tires are the same between the tires. In this case, since the direction in which the surface of the disc wheel faces is different between the two wheels, the rotation direction of the tire with respect to the mounting direction of the wheel-side transmitter / receiver during running of the vehicle is reversed. Because it becomes.

  According to a third aspect of the present invention, the tire air pressure detecting device includes a wheel side transceiver (2) and a vehicle body side transceiver (3).

  The wheel side transceiver is provided in each of a plurality of wheels (5a to 5f) provided with a tire, and a sensing unit that outputs a detection signal corresponding to the tire air pressure provided in each of the plurality of wheels (5a to 5f) ( 21) The first control unit (23a) that processes the detection signal of the sensing unit (21), the detection signal processed by the first control unit (23a), and the reception of electric waves for power charging A first transmission / reception unit (23b) and a charging unit (22) that is charged with power by a radio wave for power charging are provided.

  On the other hand, the vehicle body side transmitter / receiver is provided on the vehicle body (6) side, transmits a radio wave for power charging to the wheel side transmitter / receiver (2), and receives a detection signal and a second transmitter / receiver unit. (32a) includes a second control unit (32b) that obtains the air pressure of the tire provided on each of the plurality of wheels (5a to 5f) based on the detection signal. Moreover, the vehicle body side transmitter / receiver (3) includes one transmitting / receiving antenna (31) for each of the two wheels (5a, 5b).

  And when a 1st control part (23a) completes electric power charge, a response signal is output from the wheel side transceiver (2) mounted in the other of two wheels (5a, 5b). Instructing the first transmitting / receiving unit (23b) to transmit the detection signal only when the determination means (53) and the determination means (53) determine that the signal is not output. When the first instruction means (54) and the first transmission / reception unit (23b) transmit a detection signal, between the transmission and the completion of the next power charge, and until a certain time after the completion of the power charge, A second instructing unit (55) for instructing the first transmitting / receiving unit (23b) not to transmit the detection signal is provided.

  The present invention relates to a so-called battery-less tire pressure detecting device. And according to the present invention, once one of the two wheel side transceivers transmits the detection signal of the sensing unit once, it does not transmit even if the re-power charge is completed within a certain period of time. Can transmit the detection signal of the sensing unit.

  Thereby, the interference between two wheel side transmitter / receivers and one vehicle body side antenna can be avoided.

  The invention described in claim 2 can be combined with the invention described in claim 1. In the invention according to claim 2, the wheel side transceiver (2) transmits the detection result of the acceleration sensor (20) together with the detection signal of the sensing unit (21) from the first transceiver (23b). ing. On the other hand, the second control unit (32b) of the vehicle body side transceiver receives the detection result from the gear position detection means (8).

  Based on the detection result of the acceleration sensor (20) and the detection result of the gear position detection means (8), the second control unit (32b) receives two detection signals from the sensing unit (21). It is characterized by specifying which of (5a, 5b).

  Thereby, it is possible to specify which of the two wheels the received detection signal of the sensing unit is without using an ID. As a result, as described in the background section above, the re-registration of ID performed when the tire position is changed by tire rotation or the like can be omitted.

  On the other hand, the invention described in claim 4 can be combined with the invention described in claim 3. In the invention according to claim 4, the wheel-side transceiver (2) includes an acceleration sensor (20) that detects acceleration acting on the wheels (5a to 5f) when the wheels (5a to 5f) are rotated. The sensor (20) is arrange | positioned so that the detection result at the time of driving | running | working of a vehicle may mutually differ in two wheels (5a, 5b) among several wheels (5a-5f). The wheel-side transceiver (2) transmits the detection result of the acceleration sensor (20) together with the detection signal of the sensing unit (21).

  The second control unit (32b) of the vehicle body side transceiver 3 receives the detection result from the gear position detection means (8), and the second control unit (32b) receives the acceleration sensor (20). ) And the detection result of the gear position detection means (5), it is specified which of the two wheels (5a, 5b) the received detection signal of the sensing unit (21) is. It is characterized by that.

  Thereby, it is possible to specify which of the two wheels the received detection signal of the sensing unit is without using an ID. As a result, as described in the background section above, the re-registration of ID performed when the tire position is changed by tire rotation or the like can be omitted.

  In addition, the code | symbol in the bracket | parenthesis of each said means is an example which shows a corresponding relationship with the specific means as described in embodiment mentioned later.

(First embodiment)
A first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an overall configuration of a tire air pressure detecting device according to an embodiment of the present invention. The upper direction in the drawing of FIG. 1 corresponds to the front of the vehicle 1, and the lower direction of the drawing corresponds to the rear of the vehicle 1. With reference to this figure, the tire pressure detecting device in the present embodiment will be described.

  As shown in FIG. 1, the tire air pressure detection device is attached to a vehicle 1 and includes a wheel-side transceiver 2, a vehicle body-side transceiver 3, and a display 4. In the present embodiment, the vehicle body-side transceiver 3 includes two transmitting / receiving antennas 31a and 31b, and the first antenna 31a is disposed at a position corresponding to the two wheels of the right front wheel 5a and the left front wheel 5b. The second antenna 31b is disposed at a position corresponding to the two wheels, the right rear wheel 5c and the left rear wheel 5d.

  As shown in FIG. 1, the wheel-side transceiver 2 is attached to each wheel 5 a to 5 d in the vehicle 1. And the wheel side transmitter / receiver 2 obtains detection results such as pressure data, temperature data, etc. regarding the air pressure of the tires attached to the wheels 5a to 5d, and transmits detection signal data indicating the detection results in the transmission frame. Is stored and transmitted. The transmission frame is transmitted when a trigger signal transmitted from the vehicle body 6 side is received.

  The vehicle body side transceiver 3 is attached to the vehicle body 6 side of the vehicle 1. The vehicle body side transmitter / receiver 3 transmits a trigger signal to the wheel side transmitter / receiver 2 in order to obtain information on the tire air pressure. The vehicle body side transceiver 3 receives the transmission frame transmitted from the wheel side transceiver 2 and obtains the tire pressure by performing various processes and calculations based on the detection signals stored therein. FIGS. 2A and 2B show block configurations of the wheel side transceiver 2 and the vehicle body side transceiver 3.

  As shown in FIG. 2A, the wheel-side transceiver 2 includes a single acceleration sensor (hereinafter referred to as G sensor) 20, a sensing unit 21, a microcomputer 23, and an antenna 24. It has become. For example, the wheel-side transceiver 2 is attached to an air injection valve in a disk wheel of each of the wheels 5a to 5d, and is arranged so that the sensing unit 21 is exposed inside the tire. The components of the wheel side transceiver 2 are supplied with power by a battery (not shown).

  Here, in FIG. 3, an example of the mounting form to each wheel 5a-5d of the wheel side transmitter / receiver 2 provided with the G sensor 20 is shown. Fig. (A) is a diagram showing an arrangement form of the G sensor 20 in the tire, Fig. (B) is a partially enlarged view of Fig. (A), and Fig. (C) is attached to both front wheels 5a, 5b. It is the figure which showed the detection direction of G sensor 20. FIG.

  As shown in FIG. 3B, the G sensor 20 performs detection only with respect to accelerations generated in both directions opposite to each other (see arrows in the figure). As shown in FIG. 3A, the G sensor 20 detects acceleration in the rotational direction (circumferential direction) of the wheels 5a to 5d among the accelerations acting on the wheels 5a to 5d when the wheels 5a to 5d rotate. It is mounted in an arrangement form that can be done. The arrangement form of the G sensor 20 is the same for all the wheels 5a to 5d. When the wheels 5a to 5d are arranged so that the surface side of the disk wheel faces in the same direction, they are attached to the wheels 5a to 5d. All the G sensors 20 are arranged so as to mainly detect acceleration in the same direction. Detecting mainly means, for example, that when one rotation direction is output as a positive value and the opposite rotation direction is output as a negative value, the rotation value is output as a positive value.

  Therefore, as shown in FIG. 3C, when the wheels 5a to 5d are attached to the vehicle, for example, the right front wheel 5a rotates positively and the left front wheel 5b rotates negatively when the vehicle moves forward. For this reason, the G sensors 20 arranged on the left and right wheels 5a and 5b are in a state where they can mainly detect accelerations in different rotational directions. The G sensor 20 outputs the detection result toward the control unit 23a.

  The sensing unit 21 includes, for example, a diaphragm type pressure sensor and a temperature sensor, and outputs a detection signal corresponding to the tire pressure and a detection signal corresponding to the temperature.

  The microcomputer 23 is a known computer including a control unit (first control unit) 23a, a transmission / reception unit (first transmission / reception unit) 23b, and the like, and is stored in a memory (not shown) in the control unit 23a. In accordance with the above, a predetermined process is executed.

  The control unit 23a receives the detection signal from the sensing unit 21, processes the signal as necessary, stores it in the transmission frame as data indicating the detection result, and then transmits the transmission frame to the transmission / reception unit 23b. To send. The process of sending a signal to the transmitter / receiver 23b is executed at predetermined intervals according to the program.

  In addition, the control unit 23 a is configured to receive a detection result (detection signal) from the G sensor 20. The control unit 23a also stores the detection result of the G sensor 20 in the transmission frame described above.

  The control unit 23a determines the timing for transmitting a transmission frame (response signal) to the vehicle body-side transceiver 3 when receiving a trigger signal transmitted from the vehicle-side transceiver 3 as will be described in detail later. In addition, an instruction signal for transmission to the transmission / reception unit 23b is output.

  The control unit 23a includes a writable memory such as a RAM (not shown). The control unit 23a stores the detection result of the G sensor 20 in a writable memory after a certain period of time has elapsed since the vehicle 1 started traveling. That is, the output value n seconds after the first G sensor output is stored. This is for use when determining the transmission timing of the transmission frame described above.

  The output value of the G sensor 20 stored in the memory is rewritten every time the vehicle 1 stops.

  The transmission / reception unit 23b receives the trigger signal transmitted from the vehicle body side transceiver 3 through the antenna 24 and transmits the function as an input unit that transmits the trigger signal to the control unit 23a or the transmission frame transmitted from the control unit 23a. 24 functions as an output unit that transmits to the vehicle body side transceiver 3 through 24.

  On the other hand, as shown in FIG. 2B, the vehicle body side transceiver 3 has a configuration including an antenna 31 (first antenna 31a, second antenna 31b) and a microcomputer 32.

  The antenna 31 transmits a trigger signal to each wheel-side transceiver 2 and receives a transmission frame sent from each wheel-side transceiver 2 in general, and is fixed to the vehicle body 6. Has been.

  The microcomputer 32 is a well-known computer having a transmission / reception unit (second transmission / reception unit) 32a, a control unit (second control unit) 32b, and the like, and is stored in a memory (not shown) in the control unit 32b. In accordance with the above, a predetermined process is executed.

  The transmission / reception unit 32a inputs a transmission frame from each wheel-side transceiver 2 received by each antenna 31 and fulfills a function as an input unit that sends the transmission frame to the control unit 32b. Also, it functions as an output unit that transmits a trigger signal. In addition, although the figure has shown the case where the one transmission / reception part 32a is arrange | positioned with respect to one antenna, the one transmission / reception part 32a can also be arrange | positioned with respect to several antennas.

  The control unit 32b receives the transmission frame transmitted from the transmission / reception unit 32a. Further, a detection signal from a vehicle speed sensor 7 mounted on the vehicle and a detection signal from a gear position sensor 8 as gear position detection means are input to the control unit 32b. Although the details will be described later, the control unit 32b transmits the transmitted frame to the wheel 5a based on the detection signals from the vehicle speed sensor 7 and the gear position sensor 8 and the information on the acceleration stored in the transmission frame. Recognize any of ~ 5d.

  Further, the control unit 32b obtains the tire air pressure by performing various signal processing and calculation based on the data indicating the detection result stored in the received transmission frame, and displays an electric signal corresponding to the obtained tire air pressure. It outputs to the device 4.

  For example, the control unit 32b compares the obtained tire air pressure with a predetermined threshold value Th, and when detecting that the tire air pressure has decreased, outputs a signal to that effect to the display 4. Yes. That is, the indicator 4 is informed that the tire pressure of either the front wheels 5a, 5b or the rear wheels 5c, 5d has decreased.

  As shown in FIG. 1, the display 4 is arranged at a place where the driver can visually recognize, and is configured by an alarm lamp installed in an instrument panel in the vehicle 1, for example. For example, when a signal indicating that the tire air pressure has decreased is sent from the control unit 32b in the vehicle body side transceiver 3, the display device 4 notifies the driver of the decrease in the tire air pressure by displaying that effect. It is like that. The tire air pressure detection device is configured as described above.

  Next, the operation of the tire pressure detecting device having the above-described configuration will be described. Here, the wheel side transceiver 2 mounted on the front wheels 5a and 5b will be described as an example.

  A trigger signal is simultaneously transmitted from the first antenna 31a of the vehicle body side transceiver 3 to the right front wheel 5a and the left front wheel 5b. The trigger signal is received by the transmitter / receiver 23b via the antenna 24 by the wheel-side transmitter / receiver 2 mounted on each of the wheels 5a, 5b. Input to the controller 23a.

  Then, when a signal indicating that the signal is received is input from the transmission / reception unit 23b, the control unit 23b executes a transmission process of a response signal to the trigger signal. Here, in FIG. 4, the flowchart of the transmission process which the control part 23a of the wheel side transmitter / receiver 2 performs is shown.

  First, in step 41, a signal indicating that a trigger signal has been received is input.

  Subsequently, in step 42, it is determined whether or not a detection result is input from the G sensor 20. This is because there is an input from the G sensor 20 when the vehicle 1 is traveling, but there is no input from the G sensor 20 when the vehicle 1 is stopped.

  As a result, when it is determined that there is an input (YES), the process proceeds to step 44, and when it is determined that there is no input (NO), the process proceeds to step 43.

  In step 43, when the vehicle is stopped, the G sensor 20 does not detect acceleration, so the detection result of the G sensor 20 stored in the memory of the control unit 23a is read. Thereby, even if the vehicle 1 is stopped, the detection result of the G sensor 20 can be used.

  In step 44, it is determined from the detection result of the G sensor 20 whether or not the rotation direction of the wheels 5a, 5b is normal rotation. Here, the forward rotation is, for example, the rotation direction of the right front wheel 5a when the vehicle 1 moves forward.

  Specifically, as described above, the G sensors 20 arranged on the left and right wheels are in a state in which they can mainly detect accelerations in different rotational directions. For this reason, for example, when acceleration increases when the vehicle 1 moves forward, a positive detection signal is output from the G sensor 20 attached to the right wheel 5a, and from the G sensor 20 attached to the left wheel 5b. Outputs a negative detection signal.

  On the other hand, when the acceleration increases when the vehicle 1 moves backward, a positive detection signal is output from the G sensor 20 attached to the left wheel 5b, and a negative signal is output from the G sensor 20 attached to the right wheel 5a. A value detection signal is output. In addition, the rotation direction of the left front wheel 5b when the vehicle 1 moves forward can be set to forward rotation.

  Therefore, if the detection signal of the G sensor 20 is a positive value, it is determined that the rotation is positive (YES), and the process immediately proceeds to step 46. If the detection signal of the G sensor 20 is a negative value, the rotation is negative (NO ) And the process proceeds to Step 45.

  In step 45, after waiting for a predetermined time, the process proceeds to step 46. The predetermined time is, for example, the maximum response time.

  In step 46, an instruction signal for starting a response is output from the control unit 23a to the transmission / reception unit 23b. As a result, the transmission frame is transmitted from the transmission / reception unit 23b toward the vehicle body-side transceiver 3. In this transmission frame, the detection result of the G sensor 20 is stored as data relating to acceleration after signal processing as necessary. In this way, the transmission process is executed.

  Thereafter, each wheel-side transceiver 2 is detected by the vehicle body-side transceiver 3 based on the acceleration-related data stored in the transmission frame and the detection signals from the vehicle speed sensor 7 and the gear position sensor 8 input to the control unit 32b. It is detected which of the right front wheel 5a and the left rear wheel 5b is attached. As described above, the data related to acceleration is, for example, whether the output value of the G sensor 20 is positive or negative.

  Further, as to whether the vehicle 1 is moving forward or backward, the gear position sensor 8 functions as a traveling direction detection unit, and the gear position is, for example, the D position, the second speed position, based on the detection signal from the gear position sensor 8. The determination can be made based on whether the vehicle 1 is in a position for moving forward, such as the first speed position, or whether the vehicle 1 is in a position for moving backward.

  For this reason, the controller 32b determines whether the vehicle 1 is moving forward or backward based on the detection signal of the gear position sensor 8, and determines whether the right front wheel 5a is left or right based on the output value of the G sensor 20 at that time. By determining whether it is the front wheel 5b, it is possible to detect whether the wheel side transceiver 2 is attached to the right front wheel 5a or the left front wheel 5b.

  However, when the vehicle 1 is moving forward or backward and decelerating, the acceleration can be detected by the transmitter 2 attached to the wheels on the opposite side from when the acceleration is increasing. For this reason, since it is considered that the acceleration is increasing when the vehicle 1 starts running after the vehicle stops, it is determined from the detection signal of the vehicle speed sensor 7 that the vehicle 1 has stopped, and the G sensor 20 in a predetermined time thereafter. Based on the detection result, it is detected whether the transmitter 2 is attached to the right front wheel 5a or the left front wheel 5b.

  For the wheel side transceiver 2 mounted on the rear wheels 5c and 5d, it is possible to detect whether the wheel side transceiver 2 is attached to the right rear wheel 5c or the left rear wheel 5d by the same method. It becomes possible.

  In this manner, after the transmission frame is identified as either the right front wheel 5a or the left front wheel 5b, the tire pressure is obtained from the data indicating the detection result stored in the transmission frame. If there is an abnormality in the tire pressure, it is displayed on the display 4.

  Next, features of the tire pressure detection device of the present embodiment will be described.

  (1) As described above, in the present embodiment, in the wheel side transceiver 2, the G sensor 20 detects the acceleration in the rotation direction of the wheel, and the result is input to the control unit 23a.

  The G sensor 20 is mounted at the same position on each of the left and right wheels of the vehicle. However, in both the left and right wheels, the rotation direction of the tire with respect to the mounting direction (position) of the G sensor 20 is different because the surface of the disc wheel faces the outside of the vehicle. Therefore, the G sensor 20 of the wheel side transceiver 2 mounted on each of the left and right wheels outputs different detection results when the vehicle is traveling.

  On the other hand, the vehicle body side transceiver 3 corresponds to the first antenna 31a arranged corresponding to the two wheels of the right front wheel 5a and the left front wheel 5b, and the two wheels of the right rear wheel 5c and the left rear wheel 5d. The second antenna 31b is provided. That is, one antenna 31 is provided for each of the two wheels.

  And the control part 23a of the wheel side transmitter / receiver 2 performs the transmission process of the response signal with respect to a trigger signal, when a trigger signal is received. That is, in step 44, the control unit 23a determines whether the rotation of the wheel is a positive rotation from the detection result of the G sensor 20, and if so, the control unit 23a sends a transmission instruction signal to the transmission / reception unit 23b in step 46. By outputting, the response is started immediately. On the other hand, if the rotation is negative, in step 45, the control unit 23a waits for a predetermined time and then starts a response in step 46.

  Thus, in the present embodiment, the control unit 23a of the wheel side transceiver 2 itself determines the rotation direction of the wheel from the detection result of the G sensor 20, and the vehicle body side transceiver 3 responds to the determination result. In response to this, the timing for transmitting the response signal is determined.

  As a result, even if a trigger signal is given simultaneously from one antenna 31a on the vehicle body side to the wheel side transceiver 2 mounted on each of the left and right wheels 5a and 5b, these two wheel side transceivers are transmitted. The machine 2 can automatically shift the timing of sending the response signals. As a result, according to the present embodiment, interference between these two wheel side transceivers 2 and the vehicle body side transceiver 3 can be prevented without using the ID as described in the background section above. It can be avoided.

  (2) In the present embodiment, each of the vehicle body side transceivers 3 is based on the acceleration data stored in the transmission frame and the detection signals from the vehicle speed sensor 7 and the gear position sensor 8 input to the control unit 32b. It is detected whether the wheel-side transceiver 2 is attached to the right front wheel 5a or the left rear wheel 5b.

  As a result, as described in the background art section above, the ID re-registration performed when the tire position is changed by tire rotation or the like can be omitted. As a result, control for performing ID re-registration can be omitted.

(Second Embodiment)
In the first embodiment, the case where the vehicle has the right front wheel 5a, the left front wheel 5b, the right rear wheel 5c, and the left rear wheel 5d is described as an example. However, in the present embodiment, the vehicle is a right rear wheel, A case where there are two left rear wheels each will be described as an example.

  FIG. 5 is a block diagram showing the overall configuration of the tire pressure detecting device in the present embodiment. This embodiment is different from the first embodiment in that the right rear wheels 5c and 5e and the left rear wheels 5d and 5f are so-called double tires, and the vehicle has six wheels 5a to 5f. The wheel-side transceiver 2 is mounted on each of the six wheels 5a to 5f, and the vehicle-side transceiver 3 is provided with three transmission / reception antennas 31 (31a, 31b, 31c). .

  The transmission / reception antenna 31 of the vehicle body-side transceiver 3 includes a first antenna 31a disposed at a position corresponding to the right front wheel 5a and the left front wheel 5b in the vehicle body 6, and a second position corresponding to the right rear wheel 5c, 5e. An antenna 31b is arranged, and a third antenna 31c is arranged at a position corresponding to the left rear wheel 5d, 5f.

  Other configurations are the same as those of the tire pressure detection device described in the first embodiment.

  In so-called double tires, the inner tires 5c and 5d have the air injection valve facing outward, and the outer tires 5e and 5f have the air injection valve facing inward. For this reason, in the inner tires 5c and 5d and the outer tires 5e and 5f, the mounting direction (position) of the wheel-side transceiver 2 with respect to the tires is reversed.

  Therefore, in the wheel-side transceiver 2 mounted on the inner tires 5c and 5d and the outer tires 5e and 5f, the detection result of the G sensor 20 when the vehicle travels is the same as described in the first embodiment. Different.

  Therefore, even in a vehicle having a double tire, as in the first embodiment, the control unit 23a of the wheel-side transceiver 2 executes a transmission process of a response signal with respect to the trigger signal. Similar effects can be obtained.

  In the present embodiment, a case where the rear wheel has one axle and a so-called double tire has been described as an example (when the rear wheel has four wheels), but the rear wheel has two axles (the rear wheel has eight wheels). The present invention can also be applied to the case). In short, regardless of the number of wheels, the present invention can be applied to a vehicle whose wheels are configured by so-called double tires.

(Third embodiment)
In each of the above-described embodiments, the case where the number of G sensors 20 provided in the wheel-side transceiver 2 is one has been described as an example, but the number of G sensors 20 is set to two as in the present embodiment. You can also.

  FIG. 6 is a block diagram of the wheel-side transceiver 2 in the present embodiment. In the present embodiment, the wheel-side transceiver 2 includes two G sensors 20a and 20b. The detection signals of these G sensors 20a and 20b are input to the control unit 23a.

  FIG. 7 shows an example of a mounting form of the wheel-side transceiver 2 including the G sensors 20a and 20b on the wheels 5a to 5d. As shown in this figure, in this embodiment, each wheel side transceiver 2 includes two G sensors 20a and 20b. One G sensor 20a can detect acceleration in both directions perpendicular to the circumferential direction of the wheels 5a to 5d among the accelerations acting on the wheels 5a to 5d when the wheels 5a to 5d rotate, and the other G sensor 20b The acceleration in both directions parallel to the circumferential direction of the wheels 5a to 5d can be detected.

  FIG. 8 shows the relationship between accelerations detected by the G sensors 20a and 20b when the G sensors 20a and 20b are mounted in such a form.

  The G sensor 20a detects acceleration in both directions perpendicular to the circumferential direction of the wheels 5a to 5d, and generates an output corresponding to the gravitational acceleration. For this reason, when the wheel-side transceiver 2 is located at the position indicated by the solid line in FIG. 7 (the upper position of the wheels 5a to 5d), an output indicating the gravitational acceleration as a positive value is obtained. When the wheels 5a to 5d are rotated by 180 ° and the wheel side transceiver 2 is located at a lower position of the wheels 5a to 5d, an output indicating a gravitational acceleration as a negative value is obtained.

  On the other hand, the G sensor 20b detects accelerations in both directions parallel to the circumferential direction of the wheels 5a to 5d, and generates an output corresponding to the gravitational acceleration, similarly to the G sensor 20a. However, since the acceleration angle that can be detected by the G sensor 20b with respect to the G sensor 20a is shifted by 90 °, the phase of the output waveform corresponding to the detected gravitational acceleration is also different from the phase of the output waveform of the G sensor 20a. It is shifted by 90 °. That is, when the wheel-side transceiver 2 is located at a location indicated by a dotted line in FIG. 6, an output indicating a gravitational acceleration as a negative value is obtained. When the wheels 5a to 5d are rotated 180 ° and the wheel-side transceiver 2 is located at a position shifted by 180 ° from the position indicated by the dotted line in FIG. 7, an output indicating the gravitational acceleration as a positive value is obtained. .

  Therefore, as shown in FIG. 8, when the rotation direction of the wheels 5a to 5d is counterclockwise as shown in FIG. 8, the phase of the output waveform of the G sensor 20b is 90 ° with respect to the output waveform of the G sensor 20a. It will be in an advanced state. Conversely, when the rotation direction of the wheels 5a to 5d is clockwise as shown in FIG. 8, the phase of the output waveform of the G sensor 20b is delayed by 90 ° with respect to the output waveform of the G sensor 20a.

  As described above, when the rotation directions of the wheels 5a to 5d are reversed, the phase shifts of the output waveforms of the G sensors 20a and 20b are also reversed. Utilizing this fact, the wheel side transceiver 2 executes a transmission timing determination process of a response signal to the trigger signal, and the vehicle body side transceiver 3 identifies which wheel the transmission frame belongs to.

(Fourth embodiment)
In the present embodiment, a case where the present invention is applied to a so-called batteryless tire pressure detecting device will be described.

  FIG. 9 is a block diagram of the wheel-side transceiver 2 in the present embodiment. The wheel side transceiver 2 of the present embodiment has a configuration in which a charging unit 22 is added to the wheel side transceiver 2 shown in FIG. 2 described in the first embodiment. Other components are the same as those in the first embodiment.

  In the present embodiment, when the radio wave from the vehicle body side antenna 31 is received by the antenna 24 and the transmission / reception unit 23b of the wheel side transceiver 2, the charging unit 22 is charged with electric power. As will be described below, the control unit 23a operates the G sensor 20, the sensing unit 21, and the transmission / reception unit 23b with the charge power using the end of the power charge as a trigger, and data such as tire pressure (response signal). Is returned to the car body. Therefore, in the present embodiment, the radio wave from the vehicle body side antenna 31 for power charging corresponds to the trigger signal.

  Here, in FIG. 10, the flowchart of the transmission process of the response signal which the transmission / reception part 23b of the wheel side transmitter / receiver 2 performs is shown.

  In step 51, a power charge completion signal is input from the charging unit 22.

  In step 52, carrier sense is performed. This carrier sense is to detect whether the other wheel side transceiver 2 is transmitting a response signal, that is, transmitted from the other wheel side transceiver 2 received by the antenna 24 and the transceiver 23b. Detect the signal.

  In step 53, it is determined whether or not there is a carrier from the other wheel side transceiver 2. This step 53 corresponds to the determination means of the present invention. If it is determined that there is no carrier (YES), the process proceeds to step 54, and if it is determined that there is a carrier (NO), the process returns to step 52.

  In step 54, an instruction signal for transmitting the transmission frame toward the vehicle body side transceiver 3 is output to the transceiver 23b. This step 54 corresponds to the first instruction means of the present invention. Thereby, a response is started and the wheel side transceiver 2 transmits a transmission frame from the transceiver 23b and the antenna 24.

  In step 55, the process is waited for a predetermined time. This means that once the wheel-side transceiver 2 transmits the transmission frame, the transmission frame is not transmitted to the vehicle-body side transceiver 3 within a certain period of time even if re-power charging is completed.

  This fixed time is, for example, the total time of the MAX value of the charge time and the response time of the wheel side transceiver 2. This step 55 corresponds to the second instruction means of the present invention.

  In this way, the transmission / reception unit 23b of the wheel-side transceiver 2 executes response signal transmission processing.

  As described above, in the present embodiment, when the transmitting / receiving unit 23b of the wheel-side transceiver 2 performs carrier sense in steps 52 and 53 and determines that there is no carrier of the other wheel-side transceiver 2, step 54 is performed. The response is started at step 55 and waits for a predetermined time at step 55.

  This is due to the following reason. That is, in the so-called batteryless tire pressure detecting device, even if radio waves are transmitted from the antenna 31 of the vehicle body side transceiver 3 to the two wheel side transceivers 2 at the same time, the time for completing the power charging is usually obtained. Different. Electricity charging is performed while the tire is rotating. During the rotation of the tire, the distance between the wheel-side transceiver 2 and the vehicle body-side antenna 31 fluctuates. This is because it is affected by noise.

  Therefore, in this tire air pressure detection device, for example, the timing at which the trigger is applied to the two wheel side transceivers 2 mounted on the left and right front wheels 5a and 5b is different. Therefore, as in each of the above-described embodiments, simply delaying the response time of the other wheel-side transceiver 2 avoids interference between the two wheel-side transceivers 2 and the one vehicle-body antenna 31. It may not be possible.

  On the other hand, according to the present embodiment, once one of the two wheel-side transceivers 2 transmits a transmission frame, it does not transmit even if the repower charging is completed within a certain period of time. The other can transmit a transmission frame. Therefore, also in this embodiment, interference between the two wheel side transceivers 2 and the one vehicle body side antenna 31 can be avoided.

  In addition, the identification method of which wheel the transmission frame in the vehicle body side transceiver 3 is is the same as in each of the above-described embodiments.

1 is a block diagram illustrating an overall configuration of a tire air pressure detection device according to a first embodiment of the present invention. It is a block diagram which shows the structure of the wheel side transmitter / receiver 2 and the vehicle body side transmitter / receiver 3 in FIG. (A) is the figure which showed the arrangement | positioning form of G sensor 20 in a tire, (b) is the elements on larger scale of G sensor 20 in (a), (c) is rotation of both front wheels 5a and 5b. It is the figure which showed the example of the direction. It is a flowchart of the transmission process of the response signal with respect to the trigger signal which the control part 23a of the wheel side transmitter / receiver 2 performs. It is a block diagram which shows the whole structure of the tire pressure detection apparatus in 2nd Embodiment of this invention. It is a block diagram which shows the structure of the wheel side transmitter / receiver 2 in 3rd Embodiment of this invention. It is a figure which shows an example of the mounting form to each wheel 5a-5d of the wheel side transmitter / receiver 2 provided with G sensor 20a, 20b. It is a figure which shows the acceleration detected by each G sensor 20a, 20b in FIG. It is a block diagram which shows the structure of the wheel side transmitter / receiver 2 in 4th Embodiment of this invention. It is a flowchart of the transmission process of the response signal which the transmission / reception part 23b of the wheel side transmitter / receiver 2 in FIG. 9 performs.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Vehicle, 2 ... Wheel side transmitter / receiver, 3 ... Vehicle body side transmitter / receiver, 4 ... Display,
5a to 5d ... wheels, 7 ... vehicle speed sensor, 8 ... gear position sensor,
20 ... G sensor (acceleration sensor), 21 ... Sensing part,
22 ... Charging unit, 23 ... Microcomputer,
23a ... control unit (first control unit), 23b ... wheel side transmission / reception unit (first transmission / reception unit),
24 ... Wheel side transmitting / receiving antenna, 31 ... Car body side transmitting / receiving antenna,
32 ... microcomputer, 32a ... vehicle body side transmission / reception unit (second transmission / reception unit),
32b: Control unit (second control unit).

Claims (4)

A sensing unit (21) provided on each of the plurality of wheels (5a to 5f) provided with a tire and outputting a detection signal corresponding to the air pressure of the tire provided on each of the plurality of wheels (5a to 5f); The first control unit (23a) that processes the detection signal of the sensing unit (21), and when the trigger signal transmitted from the vehicle body is received, the detection signal processed by the first control unit (23a) A wheel side transceiver (2) including a first transceiver (23b) for transmitting;
A transmission / reception antenna (31) and a second transmission / reception unit (32a) which are provided on the vehicle body (6) side, transmit the trigger signal to the wheel-side transceiver (2) and receive the detection signal, and the detection signal And a vehicle body side transmitter / receiver (3) provided with a second control unit (32b) for obtaining air pressure of the tire provided on each of the plurality of wheels (5a to 5f) based on Because
The wheel-side transceiver (2) detects acceleration acting on the wheels (5a to 5f) when the wheels (5a to 5f) rotate, and outputs a detection result to the first control unit (23a). Comprising a sensor (20),
The acceleration sensor (20) is arranged on two wheels (5a, 5b) of the plurality of wheels (5a-5f) so that detection results at the time of traveling of the vehicle are different from each other,
The vehicle-side transceiver (3) includes one transmitting / receiving antenna (31) for each of the two wheels (5a, 5b),
When the first control unit (23a) receives the trigger signal, the first control unit (23a) transmits the detection signal to the vehicle body side transceiver (3) based on the detection result of the acceleration sensor (20). A tire pressure detecting device characterized by determining the tire pressure. The wheel side transceiver (2) is configured to transmit the detection result of the acceleration sensor (20) together with the detection signal of the sensing unit (21) from the first transceiver (23b),
The second control unit (32b) is configured to receive a detection result from the gear position detection means (8),
The second control unit (32b) receives the detection signal of the sensing unit (21) based on the detection result of the acceleration sensor (20) and the detection result of the gear position detection unit (8). 2. The tire pressure detection device according to claim 1, wherein the tire pressure detection device specifies which of the two wheels (5a, 5b). A sensing unit (21) provided on each of the plurality of wheels (5a to 5f) provided with a tire and outputting a detection signal corresponding to the air pressure of the tire provided on each of the plurality of wheels (5a to 5f); A first control unit (23a) that performs signal processing on a detection signal of the sensing unit (21), a first control unit that transmits the detection signal processed by the first control unit (23a), and a radio wave for power charging. 1 transmitter / receiver (23b), a wheel side transceiver (2) provided with a charging unit (22) that is charged by the electric wave for power charging,
A transmission / reception antenna (31) and a second transmission / reception unit (32a), which are provided on the vehicle body (6) side, transmit the electric wave for power charging to the wheel-side transceiver (2) and receive the detection signal, A vehicle body side transceiver (3) including a second control unit (32b) for determining the tire air pressure provided to each of the plurality of wheels (5a to 5f) based on a detection signal. A tire pressure detecting device,
The vehicle body side transceiver (3) includes one transmission / reception antenna (31) for each of the two wheels (5a, 5b),
The first controller (23a) outputs a response signal from the wheel-side transceiver (2) mounted on the other of the two wheels (5a, 5b) when the power charging is completed. Determining means (53) for determining whether or not
A first instruction means (54) for instructing the first transmitting / receiving unit (23b) to transmit a detection signal only when it is determined by the determination means (53) that it has not been output; ,
When the first transmission / reception unit (23b) transmits the detection signal, the first transmission / reception unit (23b) between the transmission and the completion of the next power charge and until a predetermined time after the completion of the power charge. In contrast, the tire air pressure detecting device includes second instructing means (55) for instructing not to transmit the detection signal. The wheel-side transceiver (2) includes an acceleration sensor (20) that detects acceleration acting on the wheels (5a to 5f) when the wheels (5a to 5f) rotate.
The acceleration sensor (20) is arranged on two wheels (5a, 5b) of the plurality of wheels (5a to 5f) so that detection results at the time of traveling of the vehicle are different from each other,
The wheel side transceiver (2) is configured to transmit the detection result of the acceleration sensor (20) together with the detection signal of the sensing unit (21),
The second control unit (32b) is configured to receive a detection result from the gear position detection means (8),
The second control unit (32b) receives the detection signal of the sensing unit (21) based on the detection result of the acceleration sensor (20) and the detection result of the gear position detection unit (8). 4. The tire pressure detection device according to claim 3, wherein the tire pressure detection device specifies which of the two wheels (5a, 5b).

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