JP2016137841A - Wheel position detection device and tire pneumatic pressure detection system with same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately register, as a candidate ID, ID information on a transmitter of a wheel of an own vehicle while suppressing ID information on a transmitter of a wheel of the other vehicle from being registered as a candidate ID.SOLUTION: When each candidate ID is registered, the number of pieces of ID information to be registered is narrowed down by making strict a registration condition while data update is made easy for the ID information once the ID information has been registered as the candidate ID. Specifically, a determination criterion that a vehicle is in a state of traveling and that is used as the registration condition is that a vehicle velocity equal to or higher than a first velocity at which an acceleration sensor is turned on occurs. A determination criterion that the vehicle is in a state of traveling and that is used as a data update condition is that a vehicle velocity equal to or higher than a second velocity lower than the first velocity occurs.SELECTED DRAWING: Figure 8

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 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, it is necessary to re-register the ID information of the transmitter and the positional relationship of the wheels with the receiver at the time of tire rotation or winter tire replacement. In this case, as a registration method, there is a method of registration using a tool that can communicate with an electronic control device (hereinafter referred to as TPMS-ECU) of a TPMS mounted on a vehicle at an automobile maintenance shop (for example, a dealer). As shown in FIG. 1, there is also an automatic method.

  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. That is, in the apparatus shown in Patent Document 1, automatic registration is performed based on a user's registration instruction operation, and the TPMS-ECU performs wheel position detection based on the traveling of the vehicle.

JP 2010-1222023 A

  When performing automatic registration of the ID information of each transmitter associated with the position of each wheel described above, ID information as a candidate to be registered (hereinafter referred to as candidate ID) is stored in the memory of the TPMS-ECU. Then, the transmitter of the own vehicle is finally registered from among the candidate IDs.

  At this time, if there are a large number of candidate IDs, the amount of data stored in the memory of the TPMS-ECU reaches the memory capacity, so a predetermined condition is set so that irrelevant ID information is excluded from the candidate IDs. . Specifically, when the wheel position is detected based on the acceleration detection signal detected by the acceleration sensor, the vehicle always travels, and therefore the condition of the candidate ID is that the vehicle is traveling. Can do.

  For example, the TPMS-ECU side confirms that the vehicle speed is equal to or higher than a predetermined speed (for example, 10 km / h), and acceleration on data (the acceleration sensor data indicating that the acceleration sensor is turned on in the frame transmitted from the transmitter) (Hereinafter referred to as G-ON data). In the acceleration sensor, 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 can accurately detect the acceleration is referred to as the acceleration sensor being in an on state. The transmitter is provided with a function of detecting that the acceleration sensor is turned on, and G-ON data is stored in the frame based on the detection result. Conversely, before the acceleration sensor is turned on, acceleration off data (hereinafter referred to as G-OFF data) is stored in the frame. By storing and transmitting either G-ON data or G-OFF data in the frame, it is possible to determine whether or not G-ON data is included in the TPMS-ECU.

  Thus, if G-ON data is included as a condition, the ID information of the transmitters of other vehicles can be prevented from accepting candidate IDs when the vehicle is not traveling. If the G-ON data indicating that the vehicle is traveling is not included in the frame sent from the transmitter, the ID information stored in the frame can also be excluded from the candidate ID. As a result, it is possible to reduce the amount of data stored in the memory of the TPMS-ECU. In particular, if the number of other vehicles in the same format as the own vehicle increases in the market, the number of candidate IDs of the transmitter becomes enormous and the wheel ID information of the own vehicle may not be registered. Logic that makes ID information of other vehicles excluded from candidate IDs is useful.

  However, when the predetermined vehicle speed, which is a condition that the TPMS-ECU includes in the candidate ID, is set to a lower value (for example, 10 km / h) than the vehicle speed at which the acceleration sensor is turned on, or a higher value (for example, 40 km / h). When setting, the following problems may occur.

  That is, when the predetermined vehicle speed is set to a low value, when the vehicle speed of the host vehicle is greater than the predetermined vehicle speed, the speed range in which the acceleration sensor is not turned on (range of 10 km / h to the predetermined vehicle speed) ) When a frame storing G-ON data from another vehicle is received while the host vehicle is traveling within this speed range, the ID information stored in the frame is a candidate for each transmitter of the wheels of the host vehicle. Registered as an ID. If the host vehicle continues to travel within this speed range, only those of other vehicles are registered in the candidate ID, and the memory capacity of the TPMS-ECU is filled, and the ID information of each transmitter of the wheels of the host vehicle is the candidate ID. May not be registered as.

  In addition, when the predetermined vehicle speed is set to a high value, if the own vehicle is always traveling in a state where the predetermined vehicle speed is not exceeded, the same thing as described above occurs, and the ID information of each transmitter of the wheel of the own vehicle is obtained. There is also a concern that it will not be registered as a candidate ID.

  In view of the above points, in the present invention, the ID information of the transmitter of the wheel of the own vehicle is accurately registered as the candidate ID while suppressing the registration of the ID information of the transmitter of the wheel of the other vehicle as the candidate ID. An object of the present invention is to provide a wheel position detecting device and a TPMS equipped with the same.

  In order to achieve the above object, according to the first aspect of the present invention, the second controller (33) of the receiver (3) is in a state in which the vehicle is traveling at a speed equal to or higher than a first speed set at a predetermined speed or higher. And the first determination means for determining whether or not the data indicating the state of the acceleration sensor (22) stored in the received frame satisfies the first condition that the acceleration sensor is on (S110) ), And when the first determination means determines that the first condition is satisfied, the candidate registration means (S120) for registering the identification information stored in the received frame as candidate identification information, and the candidate registration means When a frame including the registered candidate identification information is received, the vehicle is traveling at a speed equal to or higher than the second speed set to be lower than the predetermined speed, and the state of the acceleration sensor stored in the received frame is indicated. data The second determination means (S210) for determining whether or not the second condition indicating that the acceleration sensor is in the ON state is satisfied, and the second determination means determines that the second condition is satisfied. Then, data update means (S220) for updating the tooth position data at the reception timing of the received frame as new data used for wheel position detection is provided.

  As described above, when registering candidate identification information, the number of pieces of identification information to be registered is reduced by tightening the registration conditions, and the identification information once registered as candidate identification information is easily updated. It is trying to become. Specifically, a criterion for determining that the vehicle state used as the registration condition is running is that a vehicle speed equal to or higher than the first speed at which the acceleration sensor is on is generated. The criterion for determining that the vehicle state used as the data update condition is running is that a vehicle speed equal to or higher than the second speed that is lower than the first speed is generated.

  In this way, by tightening the registration conditions, it is possible to reduce the number of pieces of identification information selected as candidate identification information and prevent the memory capacity of the receiver from becoming full. Therefore, the identification information of the transmitter 2 of the wheel of the host vehicle can be accurately registered as candidate identification information while suppressing the identification information of the transmitter of the wheel of the other vehicle from being registered as candidate identification information. . Further, by making the data update condition looser than the registration condition, it is possible to easily update the data regarding the candidate identification information.

  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 a candidate ID registration process. It is a flowchart of a data update process.

  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 5d) 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 5d, detects the air pressure of the tire attached to the wheels 5a to 5d, and provides information on the tire air pressure indicating the detection result. It is stored in a frame together with the unique ID information of the transmitter 2 and transmitted. In the frame, G-ON data indicating that an acceleration sensor 22 (described later) is turned on or G-OFF data indicating that the acceleration sensor 22 is not turned on 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 at the 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 according to the present embodiment detects, for example, acceleration according to acceleration in both directions perpendicular to the radial direction of the wheels 5a to 5d, that is, the circumferential direction, among the accelerations acting on the wheels 5a to 5d when the wheels 5a to 5d rotate. Output a signal.

  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, and detects the position (angle detection) of the transmitter 2 at the wheels 5a to 5d to which the transmitters 2 are attached, or detects the vehicle speed. Yes. 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.

  Since the acceleration sensor 22 outputs detection signals corresponding to the rotation of the wheels 5a to 5d, the gravitational acceleration component is included in the detection signal during traveling, and the amplitude corresponding to the wheel rotation is increased. Signal. For example, the amplitude of the detection signal is the negative maximum amplitude when the transmitter 2 is located at the upper position around the central axis of the wheels 5a to 5d, zero when located at the horizontal position, and located at the lower position. The maximum positive amplitude is obtained. Therefore, the position of the acceleration sensor 22 can be detected based on this amplitude, and when the acceleration sensor 22 is located at an upper position around the angle of the position of the transmitter 2, for example, the central axis of each of the wheels 5a to 5d. It is possible to grasp the angle formed by the acceleration sensor 22 when the angle is set to 0 °.

  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 5d, 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 the predetermined speed as described above, the angle of the acceleration sensor 22 of each wheel 5a to 5d becomes a predetermined angle. Frame transmission is performed repeatedly through the transmission antenna 25 provided in each transmitter 2 at the timing. After that, it is possible to perform frame transmission from the transmitter 2 at the timing when the angle of the acceleration sensor 22 of each of the wheels 5a to 5d becomes a predetermined angle, but it is better to increase the transmission interval in consideration of the battery life. For this reason, when the time assumed to be necessary for wheel position detection elapses, the wheel position determination mode is switched to the regular transmission mode, and frame transmission is performed at a longer fixed period (for example, every minute), so that the TPMS-ECU 3 side A signal related to the tire pressure is periodically transmitted to. 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 acquires gear information from the brake ECU 10 through an in-vehicle LAN such as CAN as will be described later, and the teeth indicated by the number of teeth (or the number of teeth) of the gears rotated together with the wheels 5a to 5d. Get the position.

  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 performs wheel position detection 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 wheels 5a to 5d, the gear information of the wheel speed sensors 11a to 11d provided corresponding to the wheels 5a to 5d is acquired every predetermined period (for example, 10 ms). Yes.

  The gear information is information indicating the tooth positions of gears (gears) that are rotated together with the 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 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 wheel 5a to 5d to which each transmitter 2 is attached in association with the result of wheel position detection. Then, 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 wheel 5a to 5d is detected, and an electrical signal corresponding to the tire pressure is sent to CAN or the like. Is output 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. Thus, the meter 4 is informed that the tire pressure of any of the four 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 a decrease in the tire air pressure while identifying the wheels 5a to 5d. Informs that the tire pressure of the specific wheel has decreased.

  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 5d. 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 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 wheels 5a to 5d, the number of edges (or the number of teeth) of the gears at the reception timing of the frames is determined for the wheels that have received the frames. The tooth positions shown are nearly identical. However, the rotation state of the wheels 5a to 5d varies depending on road conditions, turning or lane change, and the rotation states of the 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 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 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. As a result, it is 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, which are traveling wheels. In addition, when the frame transmitted from the transmitter of the other vehicle is received when the wheel position is detected, the ID information stored in the frame can be a candidate ID. 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 transmitter 2 attached to the wheels 5a to 5d of the host vehicle is replaced, and the number of ID information of frames that can be received is In some cases, the number is 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, since the frame transmitted from the transmitter attached to the wheel of the other vehicle is not of the own vehicle, the frame is likely to vary, and the frame is transmitted from the transmitter 2 attached to the wheels 5a to 5d of the own vehicle. It is apt to be excluded from the wheel candidates earlier. 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, it is 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, which are traveling wheels, by the above method. However, if the number of candidate IDs becomes enormous during wheel position detection, the ID information of the wheels of the host vehicle may not be registered as candidate IDs. Therefore, when the frame from the transmitter 2 of the own vehicle or the transmitter of the other vehicle is received, the TPMS-ECU 3 executes the candidate ID registration process shown below, thereby increasing the number of candidate IDs. Is suppressed.

  Details of the candidate ID registration process executed by the TPMS-ECU 3 will be described with reference to the flowchart of the candidate ID registration process shown in FIG. 7 and the flowchart of the data update process shown in FIG. Note that the processing shown in FIG. 7 is performed for selecting candidate IDs to be subjected to wheel position detection when the above-described processing for detecting the wheel position of the traveling wheel is started. Then, only the candidate ID selected here is subjected to the data update process shown in FIG. 8 and is subjected to wheel position detection by the wheel position determination logic 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. When the TPMS-ECU 3 enters the ID registration mode, the TPMS-ECU 3 executes the processing shown in FIGS. 7 and 8 together with the above-described wheel position detection processing every predetermined control cycle.

  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 or not the vehicle state is traveling and G-ON data is stored in the received frame. That is, it is determined here whether or not the host vehicle is traveling and the acceleration sensor 22 provided in the transmitter 2 is in an on state.

  Whether or not the vehicle state is traveling is determined, for example, by obtaining vehicle speed data from the brake ECU 10 because the brake ECU 10 performs vehicle speed calculation based on detection signals of the wheel speed sensors 11a to 11d. Can do. In this case, generally, if the vehicle speed is generated, the vehicle state is assumed to be running, but in this step, the vehicle speed becomes equal to or higher than the predetermined vehicle speed on the basis of the predetermined vehicle speed at which the acceleration sensor 22 is turned on. The vehicle state is assumed to be traveling when the vehicle speed equal to or higher than the first speed is generated. The vehicle speed at which the acceleration sensor 22 is turned on varies depending on variations in the acceleration sensor 22, but for example, if it is 40 km / h or more, the acceleration sensor 22 is surely turned on, so the vehicle speed here is 40 km / h. It is assumed that the vehicle state is running when h or more.

  In the case of a traveling wheel, when the host vehicle is traveling, if the wheel speed of the traveling wheel reaches a predetermined speed, G-ON data is stored in the frame of the transmitter 2 attached to the traveling wheel. It will be. For this reason, when G-ON data is stored in the received frame when the vehicle state is traveling, there is a possibility that the frame is transmitted from the transmitter 2 of the wheels 5a to 5d of the host vehicle. . Therefore, in step 110, it is set as a candidate ID registration condition that the vehicle state is traveling and that the G-ON data is stored in the received frame.

  However, depending on the registration conditions of this candidate ID, the ID information of each transmitter of the wheel of the host vehicle is registered as a candidate ID, such that only those of other vehicles are registered in the candidate ID and the memory capacity of the TPMS-ECU 3 is full. There is a possibility of disappearing.

  Therefore, in the candidate ID registration process shown in FIG. 7, the vehicle speed is higher than or equal to the first speed as a determination condition that the vehicle state, which is one of the candidate ID registration conditions in the determination of step 110, is running. I am going to do that. By setting such conditions, it is possible to reduce the number of ID information selected as candidate IDs and suppress the memory capacity of the TPMS-ECU 3 from becoming full.

  If an affirmative determination is made in step 110, the process proceeds to step 120, where the ID information stored in the received frame is registered (stored) in the memory of the TPMS-ECU 3 as a candidate ID, and the process proceeds to the data update process shown in FIG. . That is, by narrowing down the candidate ID registration conditions and narrowing down the number of candidate IDs to be registered, the data update process shown in FIG. Make it easier to update data.

  In the data update process shown in FIG. 8, as in the candidate ID registration process shown in FIG. 7, first, in step 200, when a frame transmitted as an RF reception, that is, an RF band radio wave is received, the processes in and after step 210 are performed. Run.

  In step 210, whether the vehicle state is running and the received frame is of a candidate ID storing G-ON data, that is, whether it is ID information already registered in the candidate ID registration process shown in FIG. Determine whether or not. At this time, on condition that it is a candidate ID, the ID information registered as the candidate ID is not allowed to proceed to the processing after step 220.

  At this time, since it is assumed that it is a candidate ID, the determination criterion that the vehicle state is traveling is loosened from step 110. Specifically, in this step, when a vehicle speed that is lower than the predetermined vehicle speed and that can accurately calculate the vehicle speed is generated with reference to the predetermined vehicle speed at which the acceleration sensor 22 is turned on. The vehicle state is running. The vehicle speed at which the acceleration sensor 22 is not turned on varies depending on variations in the acceleration sensor 22, but for example, if it is 5 km / h, the acceleration sensor 22 is not turned on. Also, the vehicle speed that can be calculated with high accuracy varies depending on the accuracy of the wheel speed sensors 11a to 11d, but can be calculated with high accuracy if the vehicle speed is, for example, 5 km / h or more. Therefore, here, it is determined that the vehicle state is traveling when the vehicle speed is 5 km / h or more.

  The G-ON data is continuously recorded in the frame until the vehicle stops or when a predetermined time elapses after it is confirmed that the acceleration sensor 22 is turned on. included. That is, the G-ON data is not stored in the frame until the vehicle speed reaches a predetermined speed and the acceleration sensor 22 is turned on. However, once the acceleration sensor 22 is turned on, the G-ON data is reduced even if the vehicle speed decreases. Data remains stored in the frame. Therefore, even if the vehicle speed is near the second speed, which is lower than the first speed, as in step 210, the G-ON data can be confirmed.

  If the determination in step 210 is affirmative, the process proceeds to step 220, where data update is performed for one of the ID information stored in the received frame, that is, one of the candidate IDs. Specifically, for the candidate ID, gear information at the reception timing of the frame is acquired, and it is determined whether or not the number of gear edges (or the number of teeth) indicated by the gear ID is included in the variation allowable width. Data update for wheel position detection according to the wheel position specifying logic is performed. Based on this, as shown in FIG. 6, every time a frame is received, the candidate ID is updated, and the wheel position is detected.

  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, the frame for four traveling wheels is TPMS- Received by the ECU 3. Then, the TPMS-ECU 3 specifies which frame 2 is sent from the transmitter 2 attached to the wheels 5a to 5d 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 5d is detected. Thereby, the fall of the tire air pressure of each wheel 5a-5d can be detected, and it becomes possible to specify which tire air pressure of the wheels 5a-5d 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 5d, and the tire air pressure of the specific wheel is indicated to the driver. Announcing a drop in

  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, the wheel position of the traveling wheel can be specified without a large amount of data.

  When registering candidate IDs, the number of pieces of ID information to be registered is narrowed down by tightening the registration conditions, and the ID information once registered as candidate IDs can be easily updated. Yes. Specifically, a criterion for determining that the vehicle state used as the registration condition is running is that a vehicle speed equal to or higher than the first speed at which the acceleration sensor 22 is on is generated. The criterion for determining that the vehicle state used as the data update condition is running is that a vehicle speed equal to or higher than the second speed that is lower than the first speed is generated.

  Thus, by tightening the registration conditions, it is possible to reduce the number of ID information selected as candidate IDs and suppress the memory capacity of the TPMS-ECU 3 from becoming full. Therefore, it is possible to accurately register the ID information of the transmitter 2 of the wheel of the host vehicle as the candidate ID while suppressing the registration of the ID information of the transmitter of the wheel of the other vehicle as the candidate ID. Further, by making the data update condition looser than the registration condition, it is possible to easily update the data for the candidate ID.

  For this reason, even if the vehicle speed of the host vehicle is greater than the second vehicle speed, if the acceleration sensor 22 is in a speed range (eg, 10 km / h) that is not turned on, G-ON data is included in the frame. The ID information of the wheels of other vehicles that contain is not registered as a candidate ID. In addition, when the host vehicle is traveling at, for example, 50 km / h, the ID information of the wheels of other vehicles whose G-OFF data is included in the frame is not registered as candidate IDs.

  In addition, even if the vehicle speed of the host vehicle once reached the first speed and continued to travel below the first speed, the data can be updated if the vehicle speed is equal to or higher than the second speed thereafter. The wheel position detection can be completed earlier. That is, for the G-ON data, once it is confirmed that the acceleration sensor 22 is turned on, the G-ON data remains included in the frame during the wheel position detection. As long as it is determined that the vehicle is traveling at a low vehicle speed.

(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-described embodiment, as an example of detecting the wheel position on the traveling wheel side, the variation allowable width is changed at each frame reception timing, and the variation allowable width is gradually narrowed. However, the method of detecting the wheel position on the traveling wheel side may be another method, for example, a method in which the variation allowable width is constant and is not gradually narrowed.

  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, in the said embodiment, although the wheel position detection apparatus provided with respect to the vehicle 1 provided with the four wheels 5a-5d used as a driving | running | working wheel was demonstrated, also about vehicles with many wheels of a driving | running | working wheel, 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 wheel position detection is basically performed when the vehicle actually travels, but if the vehicle can rotate each wheel, such as a four-wheel drive vehicle, a device capable of virtual traveling such as a chassis dynamo. Since it can be implemented also when using, traveling is not limited to actual traveling.

  The steps shown in each figure correspond to means for executing various processes. That is, the part that executes the process of step 110 corresponds to the first determination means, and the part that executes the process of step 120 corresponds to the candidate registration means. Further, the part that executes the process of step 210 corresponds to the second determination means, and the part that executes the process of step 220 corresponds to data update.

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

Claims (4)

Applied to a vehicle (1) to which a plurality of wheels (5a to 5d) equipped 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;
After receiving the frame transmitted from the transmitter via the receiving antenna (31) provided on the vehicle body side, the candidate identification information to be registered among the identification information included in the frame is selected. In addition, from among the candidate identification information, the one corresponding to the transmitter provided on the plurality of wheels of the host vehicle is specified, and the plurality of wheels and the transmitter provided on each of the plurality of wheels are identified. A wheel position detection device comprising a receiver (3) having a second control unit (33) for detecting wheel position for storing identification information in association with each other,
The transmitter includes an acceleration sensor (22) that outputs a detection signal corresponding to acceleration including a gravitational acceleration component that changes with rotation of a wheel to which the transmitter is attached, and functions of the first control unit. Detecting that the wheel speed of the wheel to which the transmitter is attached has reached a predetermined speed at which acceleration can be detected by the acceleration sensor, and determining the state of the acceleration sensor based on the detection result. Having the function of storing the indicated data in the frame;
The first control unit has a gravitational acceleration included in the detection signal of the acceleration sensor with the central axis of the wheel to which the transmitter is attached as the center and an arbitrary position in the circumferential direction of the wheel as an angle of 0 °. The angle of the transmitter is detected based on the component, and the frame is repeatedly transmitted at a timing at which the angle becomes a predetermined transmission angle.
The second control unit is a gear having outer peripheral surfaces with different magnetic resistances that are rotated in conjunction with the plurality of wheels and have a portion of a tooth that is a conductor and a portion that is positioned between the teeth alternately repeated ( Based on detection signals of wheel speed sensors (11a to 11d) for detecting passage of teeth 12a to 12d), gear information indicating tooth positions of the gears is acquired, and the teeth at the reception timing of the frame are acquired. Based on the position, the wheel position detection is performed by identifying and registering the wheel on which the transmitter to which the frame was transmitted is attached,
In the second control unit of the receiver,
The vehicle is in a state where the vehicle is traveling at the first speed or higher set at the predetermined speed or higher, and the data indicating the state of the acceleration sensor stored in the received frame is in a state where the acceleration sensor is on. First determination means (S110) for determining whether or not the first condition is present;
If it is determined by the first determination means that the first condition is satisfied, candidate registration means (S120) for registering the identification information stored in the received frame as the candidate identification information;
When the frame including the candidate identification information registered by the candidate registration means is received, the vehicle is in a state of traveling at the second speed or higher set below the predetermined speed, and the received frame Second determination means (S210) for determining whether or not the data indicating the state of the acceleration sensor stored in the second condition satisfies the second condition that the acceleration sensor indicates that the acceleration sensor is on;
If the second determination means determines that the second condition is satisfied, the data update means updates the tooth position data at the reception timing of the received frame as new data used for the wheel position detection. (S220) is provided. The wheel position detection apparatus characterized by the above-mentioned.   The second control unit sets a variation allowable width 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 If it is out of the allowable range of variation, the frame is excluded from the candidate wheels attached to the transmitter to which the frame is transmitted, and the remaining wheels are identified as the wheels to which the transmitter from which the frame is transmitted are attached. The wheel position detection is performed by registering and the data updated by the data updating means is used as tooth position data at the reception timing of the received frame. The wheel position detection device according to 1.   The wheel position detection device according to claim 1, wherein the data indicating the state of the acceleration sensor is acceleration on data indicating that the acceleration sensor is in an on state. A tire pressure detection system including the wheel position detection device according to any one of claims 1 to 3,
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.

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