JP2016137842A - Wheel position detection device and tire pneumatic pressure detection system with same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to accurately register ID information on a transmitter attached to a spare wheel.SOLUTION: When each candidate ID that is a candidate of ID information on a transmitter of a spare wheel 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 condition that a vehicle is traveling is eliminated, and data is updated whenever a frame including G-OFF data is received. in this way, making strict the registration condition enables the number of pieces of ID information to be selected as candidate IDs from being narrowed down and suppresses a memory capacity of a TPMS-ECU from becoming full. Therefore, it is possible to accurately register the ID information on the transmitter of the spare wheel of an own vehicle as a candidate ID while suppressing ID information on a transmitter of wheels of the other vehicle from being registered as the candidate ID.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

  There is a need to perform automatic registration of ID information as described above for a spare wheel equipped with a transmitter.

  However, in the conventional ID information registration method described above, it is impossible to 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. Specifically, in the method of Patent Document 1, since the spare wheel is not rotated as it travels, the acceleration associated with the travel does not occur, and the spare wheel ID information is excluded from the ID information of the host vehicle. .

  Here, since there is no acceleration associated with traveling for the spare wheel, it may be possible to specify the ID information of the transmitter mounted on the spare wheel using the spare wheel. In other words, if data relating to the acceleration detected by the acceleration sensor is included in the frame sent from the transmitter, the ID information of the frame including the data in which no acceleration due to running has occurred is transmitted to the spare wheel transmitter. It can be identified as a thing.

  For example, acceleration on data (hereinafter referred to as G-ON data) indicating that the acceleration sensor is turned on or acceleration off data (hereinafter referred to as G-OFF data) indicating that the acceleration sensor is not turned on is framed. And it is a condition that the G-OFF data is included in the frame is that of the transmitter of the spare wheel, and the transmission of the spare wheel of the own vehicle is the one that has received a large number of receptions. It can be identified as that of the machine.

  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, 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.

  However, when the number of other vehicles in the same format as the host vehicle increases in the market, the number of candidates (hereinafter referred to as candidate IDs) to be registered as transmitter ID information in the memory of the TPMS-ECU becomes enormous. There is a possibility that the ID information of the transmitter of the spare wheel of the own vehicle cannot be specified. For example, if the number of candidate IDs is large, the amount of data stored in the memory of the TPMS-ECU reaches the memory capacity. Therefore, before the candidate ID includes the ID information of the spare wheel transmitter of the host vehicle, the memory capacity is increased. I am concerned that this will be reached.

  On the other hand, a predetermined condition can be set so that irrelevant ID information is excluded from the candidate ID. Specifically, when the wheel position of the traveling wheel is detected, the wheel position is detected based on the acceleration detection signal detected by the acceleration sensor, and the vehicle is always traveling. It can be set as a condition for the candidate ID.

  However, if the vehicle speed is set high so that the ID information of the transmitter of the spare wheel of the other vehicle becomes difficult to be registered as the candidate ID, it is transmitted from the transmitter of the spare wheel of the own vehicle. It is difficult to increase data updates for identifying spare wheels based on frame reception. For this reason, there is a problem that it becomes difficult to specify the ID information of the transmitter of the spare wheel of the own vehicle.

  An object of this invention is to provide the wheel position detection apparatus which can register exactly the ID information of the transmitter attached to the spare wheel, and TPMS provided with the same in view of the above points.

  In order to achieve the above object, according to the first aspect of the present invention, the second control unit (33) of the receiver (3) includes a received frame in which the vehicle is traveling at a predetermined speed or more. The first determination means (S110) for determining whether or not the data indicating the state of the acceleration sensor (22) stored in the first condition satisfies the first condition that the acceleration sensor is not in an on state; If it is determined that the first condition is satisfied, candidate registration means (S120) for registering the identification information stored in the received frame as candidate identification information in the transmitter (2) of the spare wheel (5e), When a frame including candidate identification information registered by the registration means is received, the data indicating the state of the acceleration sensor stored in the received frame indicates that the acceleration sensor is not in an on state. The second determination means (S210) for determining whether or not the second condition is satisfied, and if the second determination means determines that the second condition is satisfied, the candidate identification information for the received frame identification information Data updating means (S220) for updating the number of received data by increasing the number of received frames to be used by 1 when identifying one corresponding to a transmitter provided on a plurality of wheels of the host vehicle, It is characterized by being equipped.

  Thus, when registering candidate identification information as candidates for spare wheel transmitter identification information, it is temporarily registered as candidate identification information while narrowing the number of identification information registered by tightening the registration conditions. The identification information thus made is easily updated. By tightening the registration conditions, it is possible to reduce the number of pieces of identification information selected as candidate identification information and suppress the memory capacity of the TPMS-ECU 3 from becoming full. Therefore, it is possible to accurately register the identification information of the transmitter of the spare wheel of the own vehicle as the candidate identification information while suppressing the identification information of the transmitter of the wheel of the other vehicle from being registered as the 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 registration identification information. Therefore, it is possible to provide a wheel position detection device capable of accurately registering the identification information of the transmitter attached to the spare wheel.

  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 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. 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. FIG. 2 shows 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 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 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, based on the G-ON data or G-OFF data stored in the received frame and the determination result of whether or not the host vehicle is traveling in the TPMS-ECU 3, the spare of the host vehicle is used. The ID information of the transmitter 2 of the wheel 5e is also registered.

  Details of the candidate ID registration process for the spare wheel 5e 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 related to the spare wheel 5e when the wheel position is detected. Then, the data update process shown in FIG. 8 is executed only for the candidate IDs selected here, and the wheel position is detected for the spare wheel 5e. 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 entering 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 for each predetermined control cycle, selects candidate IDs, and then spare wheels 5e. The wheel position is detected.

  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 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 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. On the other hand, in the case of the spare wheel 5e, even when the host vehicle is traveling, acceleration due to traveling is not applied to the acceleration sensor 22, so that the frame of the transmitter 2 attached to the spare wheel 5e has G- OFF data is stored. For this reason, when G-OFF data is stored in the received frame when the vehicle state is running, there is a possibility that the frame is transmitted from the transmitter 2 of the spare wheel 5e of the host vehicle. Therefore, in step 110, the candidate ID registration condition is set such that the vehicle state is traveling and the G-OFF 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 of the spare wheel 5e, and the data update shown in FIG. Transition to processing. 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.

  That is, in step 210, it is determined whether or not the received frame is of a candidate ID storing G-OFF data, that is, whether or not the ID information has already been registered in the candidate ID registration process shown in FIG. 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, by updating the received number of ID information stored in the received frame by one, the data of the received number of frames for the candidate ID is updated. Based on this, the TPMS-ECU 3 detects the wheel position of the spare wheel 5e by specifying the ID information of the transmitter 2 of the spare wheel 5e. For example, the TPMS-ECU 3 registers, for example, the ID information whose number of receptions reaches a predetermined number as the ID information of the transmitter 2 of the spare wheel 5e.

  At this time, in step 210, the ID information registered as the candidate ID is prevented from proceeding to the processing subsequent to step 220 by being a candidate ID. Since it is assumed that it is a candidate ID, in step 210, by not providing a determination criterion that the vehicle state is traveling as in step 110 in FIG. The conditions are relaxed.

  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.

  However, even if it is a candidate ID, after it is registered as a candidate ID, the acceleration sensor 22 of the transmitter 2 that has transmitted a frame including the candidate ID is switched on and not the spare wheel 5e. When it becomes clear, there is no need to update the data.

  Therefore, when a frame with a candidate ID is received, if G-OFF data is included in the frame, data is updated every time a frame is received. 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, so that the position of the spare wheel 5e can be detected earlier. Can be done.

  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 when the vehicle speed is lower than the first speed as in step 210, it is possible to check the G-ON data. On the contrary, after the vehicle stops or when a predetermined time elapses after the vehicle stops, the G-OFF data is stored in the frame again. Therefore, based on this G-OFF data, it is possible to remove the ID information of spare wheels of other vehicles from the candidate ID.

  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-5d 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 decrease in tire air pressure 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, the wheel position of the traveling wheel can be specified without a large amount of data.

  Then, when registering candidate IDs that are candidates for the ID information of the transmitter 2 of the spare wheel 5e, the number of ID information to be registered is narrowed down by tightening the registration conditions and once registered as candidate IDs. The ID information is easily updated. Specifically, the registration ID is updated every time a frame including G-OFF data is received without the condition that the vehicle is running.

  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. Accordingly, the ID information of the transmitter 2 of the spare wheel 5e of the own vehicle can be accurately registered as the candidate ID while suppressing the ID information of the transmitter of the wheel of the other vehicle being registered 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 registration ID. Therefore, it is possible to provide a wheel position detection device capable of accurately registering the ID information of the transmitter 2 attached to the spare wheel 5e.

(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.

  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 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 executes the process of the first determination means, the part that executes the process of step 120 performs the candidate registration means, the part that executes the process of step 210 executes the process of the second determination means, and step 220 The part corresponds to the data update means.

1 Vehicle 2 Transmitter 3 TPMS-ECU (Receiver)
5 wheel 5a-5d traveling wheel 5e spare wheel 6 vehicle body 11a-11d wheel speed sensor 12a-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;
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. And identifying one corresponding to the transmitter provided on the plurality of wheels of the host vehicle from the candidate identification information, and identifying the plurality of wheels and the transmitter provided on each of the plurality of wheels. A wheel position detecting device including a receiver (3) having a second control unit (33) for detecting wheel positions for storing information in association with each other,
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 satisfies the first condition that the vehicle is traveling at the predetermined speed or more and the received data indicating the state of the acceleration sensor stored in the frame does not indicate that the acceleration sensor is on. First determination means (S110) for determining whether or not,
If the first determination means determines that the first condition is satisfied, candidate registration means (S120) registers the identification information stored in the received frame as the candidate identification information in the spare wheel transmitter. )When,
When a frame including the candidate identification information registered by the candidate registration unit is received, the data indicating the state of the acceleration sensor stored in the received frame indicates that the acceleration sensor is not in an on state. Second determination means (S210) for determining whether or not the second condition of being shown is satisfied;
When it is determined by the second determination means that the second condition is satisfied, the transmission provided on the plurality of wheels of the host vehicle from the candidate identification information with respect to the identification information of the received frame Wheel position detection, comprising: a data updating means (S220) for updating the number of received data by incrementing the number of received frames used to identify a device corresponding to a vehicle. apparatus.   The second control means specifies and registers, as the identification number of the transmitter of the spare wheel, the candidate identification number whose maximum reception number at which the maximum number of receptions reaches a predetermined value. The wheel position detection device according to claim 1, wherein 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.

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