JP6375970B2 - Wheel position detection device and tire air pressure detection system including the same - Google Patents

Description

  The present invention relates to a wheel position detection device that automatically detects at which position of a vehicle a target wheel is mounted, and is particularly suitable for application to a direct tire pressure detection system.

  Conventionally, there is a direct type as one of tire pressure detection systems (hereinafter referred to as TPMS: Tire Pressure Monitoring System). In this type of TPMS, a transmitter equipped with a sensor such as a pressure sensor is directly attached to a wheel side to which a tire is attached. In addition, an antenna and a receiver are provided on the vehicle body side. When a detection signal from the sensor is transmitted from the transmitter, the detection signal is received by the receiver via the antenna, and tire pressure is detected. Done.

  In such a direct TPMS, it is necessary to be able to determine whether the transmitted data is that of the own vehicle and which wheel the transmitter is attached to. For this reason, ID information for discriminating whether the vehicle is the own vehicle or another vehicle and discriminating the wheel to which the transmitter is attached is individually given in the data transmitted by the transmitter.

  In order to specify the position of the transmitter from the ID information included in the transmission data, the ID information of each transmitter needs to be registered in advance on the receiver side in association with the position of each wheel. For this reason, at the time of tire rotation or winter tire replacement, it is necessary to re-register the transmitter ID information and the wheel positional relationship with the receiver, and the user cannot freely replace the tire. Therefore, there is a need for a system that can automatically register ID information. Therefore, for example, Patent Document 1 proposes a technique for automatically registering ID information.

  Specifically, in the apparatus shown in Patent Document 1, it is detected that the wheel has reached a predetermined rotation position (rotation angle) based on the acceleration detection signal of the acceleration sensor provided in the transmitter on the wheel side, and the wheel side Frame transmission. When the user's registration instruction operation is performed, the wheel speed sensor detects the passage of the tooth of the gear rotated in conjunction with the wheel, and the wheel position is determined based on the variation width of the tooth position at the reception timing of the frame. Has been identified.

  In addition, there is a method of registering high-frequency ID information as the ID information of the own vehicle by paying attention to the reception frequency during a certain period among a plurality of received unknown ID information. In addition, based on the temperature and pressure information in the tire included in the transmission frame including a plurality of received unknown ID information, the correlation between the driving pattern of the host vehicle and the temperature and pressure in the tire is obtained, and the driving of the host vehicle is determined. There is also a method of registering ID information corresponding to a pattern as ID information of the own vehicle. Further, there is a method in which an antenna is arranged in the vicinity of each wheel, the intensity (RSSI) of the received radio wave when the antenna receives a frame is measured, and a larger value is registered as the ID information of the wheel in the vicinity of the antenna. is there.

Japanese Patent No. 5585595

  However, none of the conventional ID information registration methods described above can register the ID information of the receiver attached to both the traveling wheel and the spare wheel (auxiliary wheel) in the host vehicle while specifying the wheel position. . For example, in the method of Patent Document 1, since the spare wheel is not rotated with traveling, the acceleration accompanying the traveling does not occur, and the ID information of the spare wheel is excluded from the ID information of the own vehicle. In the method of paying attention to the reception frequency, the same reception frequency is obtained for both the traveling wheel and the spare wheel. Therefore, even if the vehicle can be registered as the ID information of the host vehicle, the wheel position is specified and each ID is specified. Information cannot be registered. Further, in the method using the traveling pattern, the spare wheel ID information is excluded from the ID information of the own vehicle because there is no change in the temperature or pressure in the tire accompanying traveling.

  In addition, in the case of the method of arranging the antenna in the vicinity of each wheel, if the antenna is also arranged in the vicinity of the spare wheel, it is possible to register the ID information of each wheel including the spare wheel. An additional component called an antenna is required, resulting in an increase in the number of components and an increase in cost.

  In view of the above points, the present invention provides a wheel position detection device capable of accurately registering ID information of a transmitter attached to a spare wheel without providing an antenna for each wheel, and a TPMS including the same. The purpose is to provide.

  In order to achieve the above-mentioned object, in the invention according to claim 1, the transmitter (2) outputs a detection signal corresponding to the acceleration that changes with the rotation of the wheels (5a to 5d) to which the transmitter is attached. In addition to having an acceleration sensor (22) for output, as a function of the first control unit (23), the wheel speed of the wheel to which the transmitter is attached reaches a predetermined speed at which the acceleration can be detected by the acceleration sensor. And has a function of storing data indicating the state of the acceleration sensor in the frame based on the detection result. In the second control unit (33) of the receiver (3), data indicating the state of the acceleration sensor stored in the received frame when the vehicle is traveling at a predetermined speed or higher is stored in the second control unit (33). First determination means (S110) for determining whether or not the condition that the acceleration sensor is not in the on state is satisfied, and if the first determination means determines that the condition is satisfied, the ID of the spare wheel (5e) Corresponding to candidate registration means (S130) for registering as information candidate and identification of spare wheel ID information from among those registered as spare wheel ID information candidates, and corresponding ID information of spare wheel And a registration means (S160) for registering with the registration.

  In this way, it is determined whether or not the condition that the data indicating that the acceleration sensor is not in the ON state is stored when the vehicle state is running, and the frame ID information when the condition is satisfied Only as a spare wheel candidate ID. And ID information of a spare wheel is specified from this registration ID. This makes it possible to accurately register the ID information of the transmitter attached to the spare wheel without providing an antenna for each wheel.

Specifically, in the first aspect of the invention, the number of frame receptions when the above condition is satisfied is measured, and a difference between the maximum number of receptions and the second largest number of receptions is a predetermined number (for example, according to claim 2 ). As described above, it is determined whether or not the predetermined number = 3) or more. When the difference between the maximum reception number and the number of received second most is equal to or greater than a predetermined number, ID information of the frame of maximum reception number has registered with the ID information of the transmitter of the spare wheel.

  Thereby, it is possible to prevent the ID information of the transmitter of the loaded other vehicle or the loaded wheel from being erroneously registered as the ID information of the transmitter of the spare wheel of the own vehicle due to data missing once.

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

1 is a diagram illustrating an overall configuration of a tire air pressure detection device to which a wheel position detection device according to a first embodiment of the present invention is applied. 3 is a diagram illustrating a block configuration of a transmitter 2. FIG. It is a figure which shows the block configuration of TPMS-ECU3. It is a timing chart for explaining wheel position detection. It is the image figure which showed the change of gear information. It is the schematic diagram which illustrated the wheel position determination logic. It is the schematic diagram which illustrated the wheel position determination logic. It is the schematic diagram which illustrated the wheel position determination logic. It is the graph which showed the evaluation result of the wheel position of ID1. It is the graph which showed the evaluation result of the wheel position of ID2. It is the graph which showed the evaluation result of the wheel position of ID3. It is the graph which showed the evaluation result of the wheel position of ID4. It is a flowchart of the spare wheel registration process which TPMS-ECU3 performs. It is a time chart when the frame reception from the spare wheel of the own vehicle and another vehicle is performed. It is a time chart when the frame reception from the spare wheel of the own vehicle and another vehicle is performed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other will be described with the same reference numerals.

(First embodiment)
A first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating an overall configuration of a TPMS to which a wheel position detection device according to a first embodiment of the present invention is applied. 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, TPMS in this embodiment is demonstrated.

  As shown in FIG. 1, the TPMS is provided in the vehicle 1, and includes a transmitter 2, an ECU for TPMS (hereinafter referred to as TPMS-ECU) 3 that plays the role of a receiver, and a meter 4. Yes. The wheel position detection device uses a transmitter 2 and a TPMS-ECU 3 provided in the TPMS, and wheels provided corresponding to each wheel 5 (5a to 5e) from a brake control ECU (hereinafter referred to as a brake ECU) 10. The wheel position is specified by acquiring gear information obtained from detection signals of the speed sensors 11a to 11d.

  As shown in FIG. 1, the transmitter 2 is attached to each of the wheels 5a to 5e including the traveling wheels 5a to 5d and the spare wheel 5e. The transmitter 2 detects the air pressure of the tires attached to the wheels 5a to 5e, and stores information related to the tire air pressure indicating the detection result in the frame together with the unique ID information of each transmitter 2 and transmits the information. Further, in the frame, acceleration on data (hereinafter referred to as G-ON data) indicating that an acceleration sensor 22 (described later) is turned on or acceleration off data (hereinafter referred to as G-ON data) indicating that the acceleration sensor 22 is not turned on. , G-OFF data) is stored. These G-ON data and G-OFF data correspond to data indicating the state of the acceleration sensor 22 in the present invention. Although the acceleration sensor 22 always detects acceleration, when the wheel speed reaches a predetermined speed, the acceleration component in the centrifugal direction becomes sufficiently larger than the other components so that accurate acceleration detection can be performed. The fact that the acceleration sensor 22 can perform accurate acceleration detection in this way is referred to as the acceleration sensor 22 being in an on state. The transmitter 2 has a function of detecting that the acceleration sensor 22 is turned on. Based on the detection result, G-ON data or G-OFF data is stored in the frame. Yes. For example, the transmitter 2 is provided with a physical switch (not shown) in which a movable contact that is displaced according to acceleration in the centrifugal direction is in contact with a fixed contact. Is detected to have been turned on.

  On the other hand, the TPMS-ECU 3 is attached to the vehicle body 6 side of the vehicle 1 and receives a frame transmitted from the transmitter 2 and performs various processes and calculations based on the detection signal stored therein. Thus, wheel position detection and tire air pressure detection are performed.

  The transmitter 2 creates a frame by, for example, FSK (frequency shift keying), and the TPMS-ECU 3 reads the data in the frame by demodulating the frame, and performs wheel position detection and tire air pressure detection. 2A and 2B show a block configuration of the transmitter 2 and the TPMS-ECU 3.

  As shown in FIG. 2A, the transmitter 2 includes a sensing unit 21, an acceleration sensor 22, a microcomputer 23, a transmission circuit 24, and a transmission antenna 25, and supplies power from a battery (not shown). Each part is driven based on the above.

  The sensing unit 21 includes, for example, a diaphragm type pressure sensor 21a and a temperature sensor 21b, and outputs a detection signal corresponding to the tire pressure and a detection signal corresponding to the temperature. The acceleration sensor 22 is used to detect the position of the sensor itself on the traveling wheels 5a to 5d to which the transmitter 2 is attached, that is, to detect the position of the transmitter 2 and the vehicle speed. The acceleration sensor 22 of the present embodiment is, for example, an acceleration acting on the traveling wheels 5a to 5d when the traveling wheels 5a to 5d rotate, in the radial direction of each traveling wheel 5a to 5d, that is, in both directions perpendicular to the circumferential direction. A corresponding detection signal is output.

  The microcomputer 23 is a well-known one having a control unit (first control unit) and the like, and executes predetermined processing according to a program stored in a memory in the control unit. Individual ID information including identification information unique to the transmitter for identifying each transmitter 2 and identification information unique to the vehicle for identifying the host vehicle is stored in the memory in the control unit.

  The microcomputer 23 receives the detection signal related to the tire pressure from the sensing unit 21, processes the signal and processes it as necessary, and stores the information related to the tire pressure in the frame together with the ID information of each transmitter 2. . Moreover, the microcomputer 23 monitors the detection signal of the acceleration sensor 22, performs position detection (angle detection) of the transmitter 2 on the traveling wheels 5a to 5d to which the respective transmitters 2 are attached, and performs vehicle speed detection. ing. When the microcomputer 23 creates a frame, the microcomputer 23 transmits a frame (data transmission) from the transmission antenna 25 to the TPMS-ECU 3 via the transmission circuit 24 based on the position detection result of the transmitter 2 and the vehicle speed detection result. )I do.

  Specifically, the microcomputer 23 starts frame transmission on the condition that the vehicle 1 is traveling, and at a timing at which the angle of the acceleration sensor 22 becomes a predetermined angle based on the detection signal of the acceleration sensor 22. Repeated frame transmission. Whether the vehicle is running is determined based on the vehicle speed detection result, and the angle of the acceleration sensor 22 is determined based on the position detection result of the transmitter 2 based on the detection signal of the acceleration sensor 22. .

  That is, the microcomputer 23 detects the vehicle speed using the detection signal of the acceleration sensor 22, and determines that the vehicle 1 is running when the vehicle speed becomes a predetermined speed (for example, 5 km / h) or more. The output of the acceleration sensor 22 includes acceleration based on centrifugal force (centrifugal acceleration). The vehicle speed can be calculated by integrating the centrifugal acceleration and multiplying the coefficient. For this reason, the microcomputer 23 calculates the centrifugal acceleration by removing the gravitational acceleration component from the output of the acceleration sensor 22, and calculates the vehicle speed based on the centrifugal acceleration.

  Further, since the acceleration sensor 22 outputs detection signals corresponding to the rotations of the traveling wheels 5a to 5d, the gravitational acceleration component is included in the detection signals during traveling, and the amplitude corresponding to the wheel rotations. A signal having For example, the amplitude of the detection signal is a negative maximum amplitude when the transmitter 2 is located at the upper position around the central axis of the traveling wheels 5a to 5d, zero when located at the horizontal position, and a position at the lower position. When it is, the maximum amplitude is positive. For this reason, the position of the acceleration sensor 22 can be detected based on this amplitude, and the acceleration sensor 22 is positioned at an upper position around the angle of the position of the transmitter 2, for example, the central axis of each traveling wheel 5a to 5d. The angle formed by the acceleration sensor 22 when the time is 0 ° can be grasped.

  Therefore, the frame transmission from each transmitter 2 is performed at the same time when the vehicle speed reaches a predetermined speed or when the acceleration sensor 22 reaches a predetermined angle after the vehicle speed reaches the predetermined speed. The frame is transmitted repeatedly at the timing when the angle formed by the acceleration sensor 22 becomes the same angle as the first frame transmission. Regarding the transmission timing, the angle formed by the acceleration sensor 22 may be the same as that at the time of the first frame transmission. However, in consideration of the battery life, the frame transmission is always performed every time the angle is reached. For example, it is preferable that frame transmission is performed only once in a predetermined time (for example, 15 seconds).

  The transmission circuit 24 functions as an output unit that transmits the frame transmitted from the microcomputer 23 to the TPMS-ECU 3 through the transmission antenna 25. For frame transmission, for example, radio waves in the RF band are used.

  The transmitter 2 configured in this way is attached to an air injection valve in each of the wheels 5a to 5e, for example, and is arranged so that the sensing unit 21 is exposed inside the tire. The transmitter 2 detects the tire air pressure of the wheel to which the transmitter 2 is attached, and when the vehicle speed exceeds a predetermined speed as described above, the angle of the acceleration sensor 22 of each traveling wheel 5a to 5d becomes a predetermined angle. At this timing, frame transmission is repeatedly performed through the transmission antenna 25 provided in each transmitter 2. After that, it is possible to transmit a frame from the transmitter 2 at the timing when the angle of the acceleration sensor 22 of each traveling wheel 5a to 5d becomes a predetermined angle, but the transmission interval is increased in consideration of the battery life. Therefore, when the time assumed to be necessary for wheel position detection elapses, the mode is switched from the wheel position determination mode to the periodic transmission mode, and frame transmission is performed at a longer fixed period (for example, every 1 minute), whereby the TPMS-ECU 3 A signal related to tire pressure is periodically transmitted to the side. At this time, for example, by providing a random delay for each transmitter 2, the transmission timing of each transmitter 2 can be shifted, and reception by the TPMS-ECU 3 side due to radio wave interference from a plurality of transmitters 2 is possible. It can be prevented from disappearing.

  Further, as shown in FIG. 2B, the TPMS-ECU 3 includes a receiving antenna 31, a receiving circuit 32, a microcomputer 33, and the like. The TPMS-ECU 3 is indicated by the number of teeth (or the number of teeth) of the gears rotated together with the traveling wheels 5a to 5d by acquiring gear information from the brake ECU 10 through an in-vehicle LAN such as CAN as will be described later. The tooth position is acquired.

  The receiving antenna 31 is for receiving a frame transmitted from each transmitter 2. The receiving antenna 31 is fixed to the vehicle body 6 and may be an internal antenna disposed in the main body of the TPMS-ECU 3, or may be an external antenna in which wiring is extended from the main body.

  The receiving circuit 32 functions as an input unit that receives a transmission frame from each transmitter 2 received by the receiving antenna 31 and sends the frame to the microcomputer 33. When receiving a signal (frame) through the receiving antenna 31, the receiving circuit 32 transmits the received signal to the microcomputer 33.

  The microcomputer 33 corresponds to a second control unit, and executes wheel position detection processing according to a program stored in a memory in the microcomputer 33. Specifically, the microcomputer 33 performs wheel position detection based on the relationship between the information acquired from the brake ECU 10 and the reception timing at which the transmission frame from each transmitter 2 is received. From the brake ECU 10, in addition to the wheel speed information of the traveling wheels 5a to 5d, the gear information of the wheel speed sensors 11a to 11d provided corresponding to the traveling wheels 5a to 5d is acquired every predetermined period (for example, 10 ms). doing.

  The gear information is information indicating the tooth positions of gears (gears) that are rotated together with the traveling wheels 5a to 5d. The wheel speed sensors 11a to 11d are configured by, for example, electromagnetic pickup sensors that are disposed to face the gear teeth, and change the detection signal as the gear teeth pass. Since these types of wheel speed sensors 11a to 11d output square pulse waves corresponding to the passage of teeth as detection signals, the rising and falling of the square pulse waves pass through the tooth edge of the gear. Will be expressed. Therefore, the brake ECU 10 counts the number of tooth edges of the gear, that is, the number of passing edges from the number of rising and falling edges of the detection signals of the wheel speed sensors 11a to 11d, and the tooth edge at that time at every predetermined cycle. The number is transmitted to the microcomputer 33 as gear information indicating the tooth position. Thereby, in the microcomputer 33, it is possible to grasp which tooth of the gear has passed.

  The number of tooth edges is reset every time the gear rotates once. For example, when the number of teeth provided on the gear is 48 teeth, the number of edges is counted in a total of 96 from 0 to 95, and when the count value reaches 95, it is returned to 0 and counted again.

  Here, the number of tooth edges of the gear is transmitted from the brake ECU 10 to the microcomputer 33 as gear information, but the number of teeth which is a count value of the number of passing teeth may be used. Further, the number of edges or teeth passed during the predetermined period is transmitted to the microcomputer 33, and the microcomputer 33 adds the number of edges or teeth passed during the predetermined period to the previous number of edges or teeth. You may make it count the number of edges or the number of teeth in the period. That is, it is only necessary that the microcomputer 33 can finally acquire the number of edges or the number of teeth in the cycle as gear information. The brake ECU 10 resets the number of gear teeth (or the number of teeth) every time the power is turned off, but again starts measuring at the same time when the power is turned on or when the vehicle speed reaches the predetermined vehicle speed. ing. Thus, even if the power is turned off every time the power is turned off, the same teeth are represented by the same number of edges (or the number of teeth) while the power is turned on.

  The microcomputer 33 measures the reception timing when the frame transmitted from each transmitter 2 is received, and the frame reception timing is determined from the number of edges (or the number of teeth) of the acquired gear. The wheel position is detected based on the number of edges (or the number of teeth) of the gear. Thereby, it becomes possible to perform wheel position detection that specifies which traveling wheel 5a to 5d each transmitter 2 is attached to. A specific method for detecting the wheel position will be described in detail later.

  Further, the microcomputer 33 stores the ID information of each transmitter 2 and the position of each traveling wheel 5a to 5d to which each transmitter 2 is attached in association with the result of wheel position detection. After that, based on the ID information stored in the transmission frame from each transmitter 2 and the data related to the tire pressure, the tire pressure of each of the traveling wheels 5a to 5d is detected, and an electrical signal corresponding to the tire pressure is sent to the CAN. To the meter 4 through the in-vehicle LAN. For example, the microcomputer 33 detects a decrease in tire air pressure by comparing the tire air pressure with a predetermined threshold Th, and outputs a signal to that effect to the meter 4 when a decrease in tire air pressure is detected. Thereby, the meter 4 is informed that the tire pressure of any of the four traveling wheels 5a to 5d has decreased.

  The meter 4 functions as an alarm unit, and as shown in FIG. 1, is arranged at a place where the driver can visually recognize, and is configured by a meter display or the like 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 microcomputer 33 in the TPMS-ECU 3, the meter 4 displays the decrease in tire air pressure while identifying the traveling wheels 5a to 5d. Informs the driver of a decrease in tire pressure of a specific wheel.

  Next, the operation of the TPMS of this embodiment will be described. Hereinafter, although the operation of the TPMS will be described, the description will be divided into wheel position detection and tire air pressure detection performed by the TPMS. First, a specific method of wheel position detection will be described with reference to FIGS.

  On the transmitter 2 side, the microcomputer 23 monitors the detection signal of the acceleration sensor 22 at every predetermined sampling period based on the power supply from the battery, thereby determining the vehicle speed and the angle of the acceleration sensor 22 at each of the wheels 5a to 5e. Detected. Then, when the vehicle speed reaches a predetermined speed, the microcomputer 23 repeatedly transmits frames at a timing at which the angle of the acceleration sensor 22 becomes a predetermined angle. For example, frame transmission from each transmitter 2 is performed with a predetermined angle when the vehicle speed reaches a predetermined speed or a start timing when the acceleration sensor 22 reaches a predetermined angle after the vehicle speed reaches the predetermined speed. I have to. The frame is transmitted repeatedly at the timing when the angle formed by the acceleration sensor 22 becomes the same angle as the first frame transmission.

  That is, when the gravitational acceleration component of the detection signal of the acceleration sensor 22 is extracted, a sine wave as shown in FIG. 3 is obtained. Based on this sine wave, the angle of the acceleration sensor 22 is known. For this reason, frame transmission is performed at the timing at which the acceleration sensor 22 has the same angle based on the sin wave.

  On the other hand, on the TPMS-ECU 3 side, the gear information of the wheel speed sensors 11a to 11d provided corresponding to the traveling wheels 5a to 5d is acquired from the brake ECU 10 at every predetermined period (for example, 10 ms). Then, the TPMS-ECU 3 measures the reception timing when the frame transmitted from each transmitter 2 is received, and the frame reception timing is determined from the number of edges (or the number of teeth) of the acquired gear. Get the number of gear edges (or the number of teeth).

  At this time, the reception timing of the frame transmitted from each transmitter 2 does not always coincide with the period in which the gear information is acquired from the brake ECU 10. For this reason, the number of edges (or the number of teeth) of the gear indicated by the gear information acquired in the cycle closest to the reception timing of the frame among the cycles in which the gear information is acquired from the brake ECU 10, that is, the cycle immediately before or immediately after that, Can be used as the number of gear edges (or the number of teeth). Further, when the frame reception timing is obtained by using the number of gear edges (or the number of teeth) indicated by the gear information acquired in the period immediately before and after the frame reception timing from the period in which the gear information is acquired from the brake ECU 10. The number of edges (or the number of teeth) of the gear may be calculated. For example, the intermediate value of the number of gear edges (or the number of teeth) indicated by the gear information acquired immediately before and after the frame reception timing is used as the number of gear edges (or the number of teeth) at the frame reception timing. Can be used.

  The operation of obtaining the number of gear edges (or the number of teeth) at the reception timing of the frame is repeated every time the frame is received, and the number of gear edges (or the number of gear edges at the received frame reception timing) The wheel position is detected based on the number of teeth. Specifically, the variation in the number of gear edges (or the number of teeth) at the frame reception timing is within a predetermined range set based on the number of gear edges (or the number of teeth) at the previous reception timing. The wheel position is detected by determining whether or not there is.

  For the wheel that has received the frame, since the frame is transmitted at the timing at which the angle of the acceleration sensor 22 reaches a predetermined angle, the tooth position indicated by the number of gear edges (or the number of teeth) at the frame reception timing Is almost the same as the previous time. For this reason, the variation in the number of edges (or the number of teeth) of the gears at the frame reception timing is small and falls within a predetermined range. This is true even when multiple frames are received, and the variation in the number of gear edges (or the number of teeth) at the reception timing of each frame is within a predetermined range determined at the first frame reception timing. It will fit. On the other hand, for a wheel different from the wheel that received the frame, the tooth position indicated by the number of edges (or the number of teeth) of the gear at the reception timing of the frame transmitted from the transmitter 2 of the other wheel varies.

  That is, since the rotation of the gears of the wheel speed sensors 11a to 11d is linked to the traveling wheels 5a to 5d, the number of edges (or the number of teeth) of the gear at the reception timing of the frame for the wheel that has received the frame. The tooth positions indicated by are almost the same. However, the rotation state of the traveling wheels 5a to 5d varies depending on road conditions, turning, lane change, etc., and therefore the traveling state of the traveling wheels 5a to 5d cannot be completely the same. For this reason, for a wheel that is different from the wheel that received the frame, the tooth position indicated by the number of gear edges (or the number of teeth) at the frame reception timing varies.

  Therefore, as shown in FIG. 4, from the state where the number of edges of the gears 12a to 12d was 0 at the time when the ignition switch (IG) was turned on, the wheel which is different from the wheel which gradually received the frame after the start of traveling. The tooth position indicated by the number of gear edges (or the number of teeth) at the frame reception timing varies. The wheel position is detected by determining whether or not the variation is within a predetermined range.

  For example, as shown in FIG. 5A, it is assumed that the position of the transmitter 2 at the first frame transmission is the first reception angle. Also, the variation allowable width, which is the allowable width for the number of gear edges (or the number of teeth), is a value corresponding to a range of 180 ° centered on the first reception angle (the range of the first reception angle ± 90 °). Suppose there is. Assume that the number of edges is a range of ± 24 edges centered on the number of edges at the first reception, and the number of teeth is a range of ± 12 teeth centered on the number of teeth at the first reception. In this case, as shown in FIG. 5 (b), if the number of gear edges (or the number of teeth) at the time of the second frame reception is within the variation allowable range determined by the first frame reception, The wheel having the number of edges (or the number of teeth) may coincide with the wheel on which the frame transmission is performed, and becomes TRUE (correct).

  However, also in this case, the variation allowable width is determined around the second reception angle that is the angle of the transmitter 2 at the time of the second frame reception, and is equivalent to 180 ° (± 90 °) around the second reception angle. Value. For this reason, a variation allowable width of 180 ° (± 90 °) centered on the first reception angle that is the previous allowable variation width and a variation allowable width of 180 ° (± 90 °) centered on the second reception angle The overlapping portion becomes a new variation allowable width (edge number range is 12 to 48), and the new variation allowable width can be narrowed to the overlapping range.

  Therefore, as shown in FIG. 5 (c), if the number of gear edges (or the number of teeth) at the time of the third frame reception is outside the range of allowable variation determined by the first and second frame reception, The wheel having the number of edges (or the number of teeth) does not coincide with the wheel on which frame transmission has been performed, and therefore FALSE (error). At this time, even if it is within the range of allowable variation determined by the first frame reception, if it is outside the range of allowable variation determined by the first and second frame reception, it is determined as FALSE. Yes. In this way, it is possible to specify which of the traveling wheels 5a to 5d the transmitter 2 that has transmitted the received frame is attached to.

  That is, as shown in FIG. 6 (a), for a frame including ID1 as ID information, the number of gear edges (or the number of teeth) is obtained at each reception timing of the frame, and the corresponding wheel is obtained. This is stored for each (left front wheel FL, right front wheel FR, left rear wheel RL, right rear wheel RR). Each time a frame is received, it is determined whether or not the acquired number of gear edges (or the number of teeth) is within the range of allowable variation, and a transmitter that transmits the frame out of the range is transmitted. 2 is excluded from the attached wheel candidates. And the wheel which was not excluded until the last is registered as a wheel with which the transmitter 2 with which the flame | frame was transmitted was attached. In the case of a frame including ID1, the right front wheel FR, the right rear wheel RR, and the left rear wheel RL are excluded from the candidates in this order, and the remaining left front wheel FL is finally attached to the transmitter 2 to which the frame is transmitted. The wheel is registered in association with the ID information.

  Then, as shown in FIGS. 6B to 6D, the same processing as that for the frame including ID1 is performed for the frame including ID2 to ID4 as the ID information. Thereby, it is possible to specify the wheel to which the transmitter 2 to which each frame is transmitted is attached, and to specify all four wheels to which the transmitter 2 is attached.

  In this way, it is specified which of the traveling wheels 5a to 5d each frame is attached to. Then, the microcomputer 33 stores the ID information of each transmitter 2 that has transmitted the frame in association with the position of the wheel to which it is attached.

  The TPMS-ECU 3 receives the frame transmitted when the vehicle speed reaches a predetermined speed to store the gear information at the reception timing. However, the TPMS-ECU 3 stores a predetermined traveling stop determination speed (for example, 5 km). / H) When it becomes below, the gear information so far is discarded. When the vehicle starts running again, the wheel position is newly detected as described above.

  The basic wheel position detection is performed by the above method. This makes it possible to detect the wheel positions of the left front wheel FL, the right front wheel FR, the left rear wheel RL, and the right rear wheel RR that are the traveling wheels 5a to 5d. In addition, when a frame transmitted from a transmitter of another vehicle is received at the time of wheel position detection, ID information that is a candidate for registration of ID information stored in the frame (hereinafter referred to as candidate ID) Can be. However, during the specification of the wheel position using the wheel position specifying logic described above, the timing at which the frame transmitted from the transmitter of the other vehicle is received does not match the tooth position of the gear of any wheel of the own vehicle. For this reason, it can avoid registering the ID information of the transmitter of another vehicle, and can register only the ID information of the transmitter 2 of the own vehicle.

  In this case, for example, if the registration method shown in Patent Document 1 is adopted, it is possible to prevent registration of ID information of a transmitter of another vehicle. That is, in the above wheel position detection, when a frame including ID information from a transmitter attached to a wheel of another vehicle is received during wheel position detection when no existing ID information of the host vehicle is registered. The ID information of the transmitter can also be a candidate ID. Similarly, even if the existing ID information of the host vehicle is registered, the number of ID information of the frames that can be received by replacing the transmitter 2 attached to the traveling wheels 5a to 5d of the host vehicle. May be less than the number of registered ID information. In such a case, when a frame including ID information from a transmitter attached to a wheel of another vehicle is received during wheel position detection, the ID information of the transmitter can also be a candidate ID.

  In these cases, only after the wheel is specified, the ID information is only included when the tooth position at the frame reception timing is included in the variation allowable range continuously for a predetermined number of times (for example, 10 times). Is registered.

  When a frame of a transmitter attached to a wheel of another vehicle is received, the number of gear edges (or teeth) acquired at each frame reception timing is also received for that frame, as in the case of the host vehicle. It is determined whether or not (number) is within the range of variation tolerance. And, similarly to the transmitter 2 of the own vehicle, for the frame transmitted from the transmitter of the other vehicle, the wheel that is out of the range of the allowable variation range is selected from the wheel candidates attached to the transmitter 2 to which the frame is transmitted. Will be excluded. At this time, since the elimination method is used, at the time when only one wheel is finally left without being excluded in each frame, the wheel candidate to which the transmitter 2 to which the wheel transmits the frame is attached. It becomes. If the ID information is registered at this time, the ID information of the transmitter attached to the wheels of the other vehicle is erroneously registered as that of the own vehicle. In particular, the frames transmitted from the transmitters attached to the wheels of the other vehicle are not subject to the own vehicle, so variations are likely to occur, and the frames are transmitted from the transmitter 2 attached to the traveling wheels 5a to 5d of the own vehicle. It tends to be excluded from wheel candidates earlier than the frame. For this reason, most of the frames transmitted from the transmitters of the wheels of other vehicles are identified as wheel candidates that are attached to the transmitters that transmitted the frames. It is easy to become the state that was done.

  However, if the ID information registration condition is that the tooth position at the reception timing of the frame is continuously included within the tolerance range after the wheel is specified, the other vehicle is in the meantime. The tooth position of the reception timing of the frame from the transmitter is out of the tolerance range. Therefore, it is possible to prevent the ID information of the transmitter attached to the wheels of the other vehicle from being erroneously registered as that of the own vehicle.

  In this case, it is assumed that it is determined whether or not the tooth position at the reception timing of the frame is continuously included a predetermined number of times after the wheel is specified, within the range of allowable variation width. Of course, it may be determined whether a predetermined number of times from the start of wheel position detection.

  As described above, the wheel positions of the left front wheel FL, the right front wheel FR, the left rear wheel RL, and the right rear wheel RR that are the traveling wheels 5a to 5d can be detected by the above-described method. However, it is the front left wheel FL, the right front wheel FR, the left rear wheel RL, and the right rear wheel RR that are the traveling wheels 5a to 5d that can detect the wheel position by the above method. For this reason, in this embodiment, the process for specifying the spare wheel 5e is further performed.

  Specifically, the TPMS-ECU 3 determines whether or not the G-ON data or G-OFF data stored in the received frame and the host vehicle are traveling, and based on the determination result The ID information of the transmitter 2 of the spare wheel 5e of the own vehicle is also registered. With reference to FIG. 7, the spare wheel registration process which TPMS-ECU3 performs is demonstrated. This process is executed together with the wheel position detection process of the traveling wheels 5a to 5d described above. For example, when the power switch is turned on to the TPMS-ECU 3 by turning on the IG, if a wheel position detection execution switch (not shown) is operated, the TPMS-ECU 3 enters the ID registration mode. And this process is performed for every predetermined | prescribed control period with the process of the wheel position detection of the above-mentioned driving | running | working wheels 5a-5d.

  First, in step 100, when an RF reception, that is, a frame transmitted as a radio wave in the RF band is received, the processing after step 110 is executed.

  In step 110, it is determined whether the vehicle state is running and whether the G-OFF data is stored in the received frame. That is, it is determined here whether or not the acceleration sensor 22 provided in the transmitter 2 is not in an on state even though the host vehicle is traveling.

  In the case of the traveling wheels 5a to 5d, when the host vehicle is traveling, if the wheel speed of the traveling wheels 5a to 5d reaches a predetermined speed, the frame of the transmitter 2 attached to the traveling wheels 5a to 5d is displayed. Will store G-ON data. However, in the case of the spare wheel 5e, even if the vehicle is running, it cannot be rotated, and therefore G-OFF data is stored in the frame of the transmitter 2 attached to the spare wheel 5e. Therefore, when the vehicle state is traveling and G-OFF data is stored in the received frame, the received frame may be transmitted from the transmitter 2 of the spare wheel 5e. Is expensive. Therefore, if an affirmative determination is made in this step, the process proceeds to step 120 and thereafter, and if a negative determination is made, the process returns to step 100.

  Whether or not the vehicle state is running is determined by obtaining vehicle speed data from the brake ECU 10, for example, because the brake ECU 10 performs vehicle speed calculation based on detection signals from the wheel speed sensors 11a to 11d. can do. In that case, it is generally considered that the vehicle state is running if the vehicle speed is generated, but here the vehicle state is running when the vehicle speed at which the acceleration sensor 22 is turned on is generated. It is said that. The vehicle speed at which the acceleration sensor 22 is turned on varies depending on the performance of the acceleration sensor 22, but if the acceleration sensor 22 is, for example, 40 km / h or more, the acceleration sensor 22 is surely turned on, so the vehicle speed is 40 km / h or more. It is assumed that the vehicle state is running.

  In step 120, it is determined whether or not the ID information stored in the currently received frame is the ID received for the first time. Here, if an affirmative determination is made, the process proceeds to step 130 and registered as a candidate ID. If a negative determination is made, since the ID information stored in the frame received this time has already been registered, the process proceeds to step 140 to add the number of received candidate IDs that have been registered.

  Thereafter, the process proceeds to step 150 and subsequent steps, and it is determined whether the received frame is the transmitter 2 of the spare wheel 5e of the own vehicle or the transmitter of the other vehicle. If the frame is transmitted from the transmitter 2 of the spare wheel 5e of the host vehicle, the ID information of the frame is registered as that of the spare wheel 5e.

  Specifically, in step 150, it is determined whether the difference between the maximum number of receptions and the second largest number of receptions is 3 or more and the maximum number of receptions is 4 or more. Thereby, it is determined whether the received frame is the transmitter 2 of the spare wheel 5e of the own vehicle or the transmitter of the other vehicle. This will be described with reference to time chart examples shown in FIGS.

  When the vehicle state of the host vehicle is running and the G-OFF data is stored in the received frame, the frame is basically attached to the spare wheel 5e of the host vehicle. A transmitter 2 is assumed. However, there may be a case where the frame is not transmitted by the transmitter 2 of the spare wheel 5e of the own vehicle. For example, when there is another vehicle running side by side with the host vehicle, there is a possibility that the frame is transmitted from a spare wheel transmitter of the other vehicle. Further, when another vehicle or wheel is loaded on the host vehicle, there is a possibility that the frame is transmitted from a wheel of another vehicle being loaded or a transmitter of the loaded wheel.

  However, after loading, the loaded other vehicle or loaded wheel is separated from the host vehicle, so that the frame transmitted from the loaded vehicle wheel or loaded wheel transmitter cannot be received. For this reason, a difference occurs in the number of received frames, and a frame with a large number of received frames is transmitted from the transmitter 2 of the spare wheel 5e of the own vehicle. It can be determined that it is transmitted from the transmitter of the loading wheel.

  For example, as shown in FIG. 8, a frame transmitted from the transmitter 2 of the spare wheel 5e of the host vehicle and a frame transmitted from the transmitter of the other vehicle or the loaded wheel are transmitted every predetermined frame transmission timing (for example, at intervals of 96 s). ). The transmitter 2 normally performs acceleration detection or the like at a low frequency (for example, at intervals of 16 s) in order to suppress current consumption. When the acceleration sensor 22 is not in an on state, the frequency is even lower than normal (for example, at an interval of 96 s). Acceleration detection and so on are performed.

  Here, it is assumed that a frame transmitted from the transmitter of the other vehicle or the loaded wheel is first received, and then a frame transmitted from the transmitter 2 of the spare wheel 5e of the own vehicle is received.

  In that case, the frame transmitted from the transmitter 2 of the spare wheel 5e is not yet received when the frame transmitted from the transmitter of the other vehicle or the loaded wheel is received immediately. For this reason, the difference between the maximum received number and the second most received number is that the number of received frames transmitted from the transmitter 2 of the spare wheel 5e is 0 and the frame transmitted from the transmitter of the other vehicle or the loaded wheel Since the number of reception is 1, it is 1.

  Subsequently, when a frame transmitted from the transmitter 2 of the spare wheel 5e is received, the difference between the maximum received number and the second most received number is the reception of the frame transmitted from the transmitter 2 of the spare wheel 5e. The number is 1, and the number of received frames transmitted from the transmitter of the other vehicle or the loaded wheel is 1, so it is 0. As described above, after the state where the difference between the maximum number of receptions and the second largest number of receptions is 0 or 1 is repeated, after loading, if the loaded other vehicle or loaded wheel leaves the own vehicle, the other vehicle or The number of received frames transmitted from the loading wheel transmitter does not increase. For this reason, the difference between the maximum reception number and the second most reception number is finally 3 or more, and it can be determined that the ID information of the frame with the maximum reception number is the ID information of the transmitter 2 of the spare wheel 5e.

  Here, when the difference between the maximum reception number and the second most reception number is 2 or more, it is determined that the ID information of the frame with the maximum reception number is the ID information of the transmitter 2 of the spare wheel 5e. Is also possible. However, it is possible that the frame transmitted by the transmitter 2 of the spare wheel 5e is not received by the TPMS-ECU 3 due to data collision during transmission or interference of disturbing radio waves. In this case, as shown in FIG. 9, when the frame transmitted from the transmitter 2 of the spare wheel 5e is not received by the TPMS-ECU 3, the difference between the maximum reception number and the second most reception number is 2. End up.

  Therefore, when the difference between the maximum received number and the second most received number is 3 or more, it is determined that the ID information of the frame with the maximum received number is the ID information of the transmitter 2 of the spare wheel 5e. . As a result, it is possible to prevent the ID information of the transmitter of the loaded other vehicle or the loaded wheel from being erroneously registered as the ID information of the transmitter 2 of the spare wheel 5e of the own vehicle due to data missing once. In particular, as the transmission timing is shorter, data collision is more likely to occur, and there is a possibility that the frame transmitted by the transmitter of the spare wheel 5e may not be received by the TPMS-ECU 3. It is effective to set the difference from the large number of receptions to 3 or more.

In step 150, it is also determined that the maximum number of receptions is 4 or more, but this may be too small if only the number of receptions is 3, and reliability is ensured by securing a certain number of receptions. It is for improving. Here, the maximum number of receptions is set to 4 or more. However, the higher the lower limit value, the better the reliability. However, as the lower limit value is increased, more time is required for wheel position detection, so the lower limit value of the maximum number of receptions is set to 4 times here.

  Thus, in step 150, it is determined that there is a difference between the maximum number of receptions and the second largest number of receptions. Then, when an affirmative determination is made in step 150, the process proceeds to step 160, and the ID information of the maximum number of received frames is registered as the ID information of the transmitter 2 of the spare wheel 5e of the own vehicle, thereby transmitting the spare wheel 5e. Registration of the ID information of the machine 2 is completed.

  When wheel position detection is performed in this manner, tire air pressure detection is performed thereafter. Specifically, at the time of tire pressure detection, a frame is transmitted from each transmitter 2 at regular intervals, and every time a frame is transmitted from each transmitter 2, four traveling wheels and spare wheels are transmitted. The frame is received by the TPMS-ECU 3. Then, the TPMS-ECU 3 identifies which frame is sent from the transmitter 2 attached to the wheels 5a to 5e based on the ID information stored in each frame, and determines each frame from information related to tire pressure. The tire pressure of the wheels 5a to 5e is detected. Thereby, the fall of the tire air pressure of each wheel 5a-5e can be detected, and it becomes possible to specify which tire air pressure of the wheels 5a-5e is falling. When a decrease in tire air pressure is detected, the fact is notified to the meter 4 so that the meter 4 displays the wheel air pressure decrease while identifying the wheels 5a to 5e, and the tire air pressure of the specific wheel is indicated to the driver. Announcing a drop in

  In this case, the spare wheel 5e is excluded from the notification target when the tire pressure decreases because the tire pressure does not hinder even if the tire pressure is decreased, and the tire pressure of the traveling wheels 5a to 5d is matched. Only a decrease in tire air pressure may be reported.

  As described above, the tooth positions of the gears 12a to 12d are indicated based on the detection signals of the wheel speed sensors 11a to 11d that detect the passage of the teeth of the gears 12a to 12d rotated in conjunction with the wheels 5a to 5d. Gear information is acquired every predetermined period. And if the variation allowable width is set based on the tooth position at the reception timing of the frame and the tooth position at the reception timing of the frame after setting the variation allowable width is outside the range of the variation allowable width, The wheel is excluded from the wheel candidates attached to the transmitter 2 to which the frame is transmitted, and the remaining wheels are registered as wheels to which the transmitter 2 to which the frame is transmitted is attached. For this reason, it is possible to specify the wheel positions of the traveling wheels 5a to 5d even if a large amount of data is not prepared.

  Further, as spare wheel registration processing, it is determined whether or not G-OFF data is stored when the vehicle state is traveling, and only ID information of a frame in which the G-OFF data is stored during traveling is used as a spare wheel. Register as a candidate ID of 5e. And ID information of spare wheel 5e is specified from this registration ID. Specifically, the number of receptions of frames in which G-OFF data is stored during traveling is measured, and it is determined whether the difference between the maximum number of receptions and the second largest number of receptions is a predetermined number (for example, 3) or more. ing. When the difference between the maximum reception number and the second most reception number is equal to or greater than a predetermined number, the ID information of the frame with the maximum reception number is registered as the ID information of the transmitter 2 of the spare wheel 5e. . Thereby, the ID information of the transmitter 2 of the spare wheel 5e can be registered, and the ID information of the loaded other vehicle or the transmitter of the loaded wheel is erroneously entered for the spare wheel 5e of the own vehicle in order to omit data once. Registration as ID information of the transmitter 2 can be prevented.

  Since the ID information of the transmitter 2 of the traveling wheels 5a to 5d and the spare wheel 5e can be registered in this way, it is not necessary to provide an antenna for each wheel, and the number of parts increases due to the need for additional parts. As a result, high costs can be avoided.

(Other embodiments)
The present invention is not limited to the embodiment described above, and can be appropriately changed within the scope described in the claims.

  For example, in the above embodiment, the determination condition that the vehicle state in step 110 in FIG. 7 is traveling may be changed. For example, for ID information that has been affirmed once in the determination of step 110 and registered as a candidate ID, the vehicle speed serving as a threshold when determining that the vehicle state is traveling is reduced, or the vehicle is traveling The vehicle speed condition may be relaxed by avoiding the above condition. In other words, even when the vehicle speed decreases or the vehicle stops, the ID information registered as the candidate ID may be updated when the frame is received.

As described above, when the vehicle speed exceeds the predetermined speed based on the detection signal of the acceleration sensor 22 and the vehicle is in the wheel position determination mode, frame transmission is performed from the transmitter 2 at a shorter time interval than before. However, since no acceleration is applied to the spare wheel 5e as it travels, the wheel position determination mode is not established, and the transmitter 2 performs frame transmission in the regular periodic transmission mode cycle. Alternatively, when a stop transmission mode in which a longer transmission cycle is set during stoppage than in the regular transmission mode, frame transmission is performed with a longer cycle. Accordingly, the number of times of transmission of the frame from the transmitter 2 of the spare wheel 5e is significantly smaller than that of the traveling wheels 5a to 5d. Therefore, the conditions for the candidate ID are relaxed and the data is updated every time a frame is received. Is preferable.
As a result, the spare wheel 5e having a long transmission cycle can be updated every time a frame is received, and the number of data updates can be increased. Can be done.

  Further, in the above-described embodiment, as an example of detecting the wheel position on the traveling wheels 5a to 5d side, the variation allowable width is changed at each frame reception timing, and the variation allowable width is gradually reduced. did. However, other methods may be used as a method of detecting the wheel position on the traveling wheels 5a to 5d side.

  Further, in the above embodiment, the variation allowable width is changed at each frame reception timing so that the variation allowable width is gradually narrowed. However, the variation allowable width set around the tooth position is constant. . The variation allowable width set around this tooth position can also be changed. For example, the variation in the tooth position may increase as the vehicle speed increases. For this reason, it is possible to set a more accurate variation allowable width by increasing the variation allowable width as the vehicle speed increases. In addition, the longer the sampling period when the acceleration sensor 22 performs acceleration detection, the lower the timing detection accuracy when the angle of the acceleration sensor 22 becomes a predetermined angle, and therefore the variation tolerance is changed accordingly. Thus, a more accurate variation tolerance can be set. In that case, since the transmitter 2 knows the sampling period and the like, the frame transmitted by the transmitter 2 can be transmitted including data for determining the variation allowable width.

  Moreover, in the said embodiment, it is set as the time when the acceleration sensor 22 is located in the upper position centering on the center axis | shaft of each wheel 5a-5d as an angle which performs flame | frame transmission. However, this is merely an example, and an arbitrary position in the circumferential direction of the wheel may be set to 0 °.

  In the above embodiment, the TPMS-ECU 3 acquires gear information from the brake ECU 10. However, since it is sufficient that the TPMS-ECU 3 can acquire the number of tooth edges or the number of teeth of the gear as the gear information, it may be acquired from another ECU, or the detection signals of the wheel speed sensors 11a to 11d are input, The number of teeth or the number of teeth of the gear may be acquired from the detection signal. In particular, in the above-described embodiment, the case where the TPMS-ECU 3 and the brake ECU 10 are configured by separate ECUs has been described. However, the TPMS-ECU 3 and the brake ECU 10 may be configured by a single ECU in which these are integrated. In that case, the ECU directly inputs the detection signals of the wheel speed sensors 11a to 11d, and acquires the number of teeth or the number of teeth of the gear from the detection signals. In that case, since the number of teeth or the number of teeth of the gear can always be obtained, unlike the case where these pieces of information are obtained every predetermined period, based on the gear information exactly at the reception timing of the frame. Wheel position detection can be performed.

  Moreover, although the said embodiment demonstrated the wheel position detection apparatus provided with respect to the vehicle 1 with which the driving | running | working wheels 5a-5d and the spare wheel 5e were equipped, about the vehicle with many wheels of the driving | running | working wheels 5a-5d further. Similarly, the present invention can be applied.

  In the present invention, it is only necessary that the wheel speed sensors 11a to 11d can detect the passage of gear teeth that are rotated in conjunction with the rotation of the wheels 5a to 5d. For this reason, as a gear, what is necessary is just the structure from which the magnetic resistance differs in which the part located in between the tooth | gear part by which the outer peripheral surface was made into the conductor, and a tooth | gear is repeated. In other words, the outer edge portion is made uneven so that the outer peripheral surface is not only a general structure composed of a convex portion that becomes a conductor and a space that becomes a nonconductor, but, for example, the outer peripheral surface becomes a conductor and a nonconductor A rotor switch composed of an insulator is also included (see, for example, Japanese Patent Laid-Open No. 10-048233).

  The steps shown in each figure correspond to means for executing various processes. That is, the part that executes the process of step 110 is the first determining means, the part that executes the process of step 120 is the second determining means, the part that executes the process of step 130 is the candidate registration means, and the process of step 140 is executed. The portion corresponds to reception number adding means. Further, the part that executes the process of step 150 corresponds to the third determination means, and the part that executes the process of step 160 corresponds to the registration means.

1 Vehicle 2 Transmitter 3 TPMS-ECU (Receiver)
5a to 5d wheels (running wheels)
5e Spare wheel 6 Car body 11a to 11d Wheel speed sensor 12a to 12d Gear 21 Sensing unit 22 Acceleration sensor

Claims (3)

Applied to a vehicle (1) to which a plurality of wheels (5) including a traveling wheel (5a to 5d) and a spare wheel (5e) provided with tires are attached to a vehicle body (6);
A transmitter (2) having a first control unit (23) that is provided on each of the plurality of wheels and generates and transmits a frame including unique identification information;
The transmitter which is provided on the vehicle body side and has transmitted the frame for each of the identification information included in the frame by receiving a frame transmitted from the transmitter via a receiving antenna (31). Wheel position detection for identifying which of the plurality of wheels is attached, and storing the plurality of wheels and the identification information of the transmitter provided on each of the plurality of wheels in association with each other. A wheel position detection device comprising a receiver (3) having a second control unit (33) to perform,
The transmitter includes an acceleration sensor (22) that outputs a detection signal corresponding to an acceleration that changes with rotation of a wheel to which the transmitter is attached, and the transmitter has a function as a function of the first control unit. Detecting that the wheel speed of the wheel to which the wheel is attached has reached a predetermined speed at which the acceleration sensor can detect the acceleration, and indicating the state of the acceleration sensor based on the detection result. Has the function of storing in
In the second control unit of the receiver,
Whether the vehicle is traveling at the predetermined speed or higher and the received data indicating the state of the acceleration sensor stored in the frame satisfies a condition that the acceleration sensor is not on First determination means (S110) for determining whether or not
If it is determined by the first determination means that the condition is satisfied, candidate registration means (S130) for registering as a candidate for identification information of the spare wheel;
Registration means (S160) for identifying the spare wheel identification information from among the registered spare wheel identification information candidates, and registering the identification information in association with the spare wheel. Is provided ,
In the second control unit,
If it is determined by the first determination means that the condition is satisfied, it is determined whether or not the identification information stored in the frame has been received for the first time, and is determined to have been received for the first time. Then, a second determination unit (S120) that causes the candidate registration unit to register the spare wheel identification information as a candidate,
If it is determined by the second determination means that it has not been received for the first time, the identification information stored in the received frame out of the spare wheel identification information candidates already registered by the candidate registration means Received number adding means (S140) for adding the received number of objects;
Judgment is made as to whether or not the difference between the maximum number of receptions having the highest number of receptions and the number of receptions having the second highest number among the candidates for identification information of the spare wheel added by the reception number addition means has become a predetermined value or more And a third determination means (S150) for performing,
When the third determination unit determines that the difference is equal to or greater than the predetermined value, the registration unit determines the spare wheel identification information that is the maximum reception number as the spare wheel identification information. A wheel position detecting device which is registered as: The wheel position detection device according to claim 1 , wherein the third determination unit determines whether or not the difference is 3 or more as the predetermined value. A tire pressure detection system including the wheel position detection device according to claim 1 or 2 ,
The transmitter includes a sensing unit (21) that outputs a detection signal corresponding to an air pressure of the tire provided in each of the plurality of wheels, and the detection signal of the sensing unit is signal-processed by the first control unit. After storing information about tire pressure in a frame, send the frame to the receiver,
In the tire pressure detection system, the receiver detects air pressure of the tire provided in each of the plurality of wheels from the information related to the tire pressure in the second control unit.

Images