JP2016047668A - Tire position registration system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tire position registration system for determining a tire position in a short time and registering the tire position in a receiver.SOLUTION: When a TPMS receiver 12 receives an electric wave Sva (valve ID) transmitted from a tire valve 4, axle rotation information Dc (count value Ct) of each of axles 18a to 18d is acquired, and modulo calculation for the information is performed by considering the maximum count number "96" and its divisors, "32" and "48" as rules. Then, axles of which modulo calculation result are congruence, from among each of the axles 18a to 18d, are associated with the valve ID. This is performed for every valve ID to specify tire positions of four wheels.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a tire position registration system for registering a tire valve ID in a receiver in association with a tire mounting position.

  2. Description of the Related Art Conventionally, as one function of a tire pressure monitoring system, a tire position registration system that automatically registers a tire valve ID (valve ID) in a receiver without using a trigger device such as an initiator is well known (Patent Document 1). Etc.). Patent Document 1 links the valve ID and the axle by confirming the coincidence between the gravity information of the gravity sensor provided in the tire valve and the output information of the axle rotation detection unit that detects the rotation of the axle. Identify the tire position. If the initiator is not required for registering the valve ID in the receiver, the number of components mounted on the vehicle can be reduced.

Special table 2011-527971 gazette

However, Patent Document 1 has a problem that it takes time to specify the tire position because a large amount of gravity information is required to determine the tire position.
An object of the present invention is to provide a tire position registration system capable of determining a tire position in a short time and registering it in a receiver.

  A tire position registration system that solves the above problem is necessary for transmitting a radio wave including tire pressure data from a tire valve of each tire, and for monitoring the air pressure of each tire by receiving the radio wave with a receiver of the vehicle body. In the configuration in which the ID of the tire valve is registered in the receiver in association with the tire position, each axle is triggered by receiving the radio wave transmitted when the tire valve takes a specific position by the receiver. The axle rotation information output from the axle rotation detection unit provided in the information acquisition unit for acquiring a value corresponding to the specific position, and the axle rotation information for the valve ID by receiving the radio wave from the tire valve When acquired, whether the value of the axle rotation information falls within an allowable range centered on a reference point corresponding to the timing at which the tire valve transmits a radio wave. Or verify, the verify, performed each time it receives the radio waves, by association of the valve ID and the axle, and a position determination unit determines the tire position.

  According to this configuration, it is confirmed whether or not the axle rotation information acquired upon reception of the radio wave transmitted from the tire valve is within the allowable range, and if this axle rotation information is within the allowable range, the radio wave is transmitted. The valve ID included and the axle are linked. This process is performed for each valve ID, and the tire positions of all the wheels are specified. In the case of this configuration, the tire position is confirmed each time radio waves are received, and this confirmation can be repeated until the tire positions of all wheels can be identified. The process can be terminated. For this reason, in determining the tire position, it is not necessary to collect information necessary for position determination over a predetermined time (long time) in advance. Therefore, the tire position can be determined and registered in the receiver in a short time.

  In the tire position registration system, it is preferable that the allowable range is set in a range that takes into account tolerances in radio transmission of the tire valve and vibrations that may occur in the tire during traveling. According to this configuration, it is possible to set the allowable range to the optimum range required for the actual tire position determination.

  In the tire position registration system, the information acquisition unit measures the axle rotation information with a counter, and the position determination unit includes a maximum count number that is a maximum value of the counter when the tire rotates once, and Using the divisors obtained by factoring the maximum count as the modulo, the obtained count value as the axle rotation information is modulo calculated, and based on the calculation result, which valve ID is associated with which axle It is preferable to confirm whether it is attached. According to this configuration, the axle rotation information is modulo calculated by a plurality of methods, and if the calculation results of the modulo calculation are the same, the valve ID and the axle are linked. Therefore, the tire position can be determined by a simple calculation called modulo calculation.

  In the tire position registration system, the position determination unit, when counting the axle rotation information by the counter in the modulo calculation, executes counting by the counter with the half value of the divisor or a value in the vicinity thereof as a reset value. It is preferable to do. According to this configuration, when checking the association between the valve ID and the axle by modulo calculation, it is possible to match the calculation results of the modulo calculation in the valve ID and the axle that form a pair.

  In the tire position registration system, the position determination unit is derived from a plurality of modulus values used in the modulo calculation with respect to a calculation result for each axle, which is either congruent or non-congruent in the modulo calculation. It is preferable to perform weighting based on the characteristic value and determine the tire position based on the weighting result. According to this configuration, for example, even if the modulo calculation is not congruent, the calculation result can be weighted and used to determine the tire position. Therefore, even if the axle rotation information may be out of the allowable range due to, for example, sudden vibration of the vehicle body, the information acquired at this time can be used for determining the tire position without wasting it. Become.

  In the tire position registration system, it is preferable that the position determination unit narrows down the combinations while taking into consideration the determination result of the other wheel when associating the valve ID and the axle of each tire. According to this configuration, it is possible to efficiently narrow down the valve ID and the axle connection, which is further advantageous in completing the tire position in a short time.

  In the tire position registration system, the position determination unit determines whether or not the axle rotation information is within the allowable range, and then performs the next determination after waiting for reception of the radio wave a predetermined number of times. As described above, it is preferable to execute the determination at intervals of a predetermined number of receptions of the radio wave. According to this configuration, when confirming the association between the valve ID and the axle, a difference is more likely to occur between the wheels if the values at the time of receiving the radio wave several times ahead are compared. Therefore, it is advantageous for determining the tire position at an early stage.

  According to the present invention, the tire position can be determined and registered in the receiver in a short time.

The lineblock diagram of the tire position registration system of one embodiment. The outline figure in which a tire valve transmits an electric wave in the peak position. The waveform change figure of a gravity signal when driving on a paved road and a rough road. The change figure of the value which each counter of the own wheel and other wheels at the time of valve ID reception takes. The table | surface which shows an example of the valve ID and axle modulo calculation result which make a group. The table | surface which shows an example of the modulo calculation result of valve | bulb ID which does not make a group, and an axle. The table | surface which shows the joint / non-congruent relationship of a modulo calculation when a modulo calculation is performed in multiple times. Explanatory drawing which showed the modulo calculation of tire position determination geometrically. Explanatory drawing which showed the modulo calculation of tire position determination geometrically. The table explaining the weighting for the modulo calculation result. The timing diagram which shows the implementation interval of another example of modulo calculation.

Hereinafter, an embodiment of a tire position registration system will be described with reference to FIGS.
As shown in FIG. 1, the vehicle 1 includes a tire pressure monitoring system (TPMS: TPMS) 3 that monitors the air pressure and the like of each tire 2 (2a to 2d). The tire air pressure monitoring system 3 includes tire valves 4 (4a to 4d) that detect air pressures in the tires 2a to 2d, respectively. The tire valve 4 is a tire valve sensor in which a tire plug is provided with a sensor and a communication function. The tire pressure monitoring system 3 transmits a radio wave Sva associated with at least pressure data and ID from the tire valves 4a to 4d to the vehicle body 5, and monitors the air pressure of the tires 2a to 2d in the vehicle body 5.

  The tire valve 4 detects a controller 6 that controls the operation of the tire valve 4, a pressure detection unit 7 that detects tire air pressure, a temperature detection unit 8 that detects the temperature of the tire 2, and gravity that occurs in the tire valve 4. And a transmission antenna 10 capable of transmitting radio waves in the tire valve 4. A valve ID is written and stored in the memory 11 of the controller 6 as a unique ID of each tire valve 4. The pressure detection part 7 consists of a pressure sensor, for example. The temperature detection part 8 consists of a temperature sensor, for example. The gravity detection unit 9 is composed of, for example, an acceleration sensor (G sensor). The transmission antenna 10 can transmit radio waves in, for example, a UHF (Ultra High Frequency) band.

  The vehicle body 5 includes a receiver (hereinafter referred to as a TPMS receiver 12) that monitors the air pressure of the tires 2a to 2d based on the radio wave Sva including the tire air pressure data transmitted from the tire valves 4a to 4b. The TPMS receiver 12 includes a tire pressure monitoring ECU (Electronic Control Unit) 13 that controls the operation of the TPMS receiver 12 and a receiving antenna 14 that enables radio waves to be received by the TPMS receiver 12. In the memory 15 of the tire pressure monitoring ECU 13, valve IDs acquired from the respective tire valves 4a to 4d are written and stored in association with tire positions. The TPMS receiver 12 is connected to a display unit 16 that displays the monitoring result of the tire air pressure. The display part 16 is good to be installed, for example in the instrument panel in a vehicle.

  When the receiving antenna 14 receives the radio wave Sva transmitted from the tire valves 4a to 4d at a certain timing, that is, the tire pneumatic radio wave including at least pressure data and valve ID, the TPMS receiver 12 collates the valve ID in the radio wave Sva. If the valve ID verification is established, the pressure data (air pressure data) in the same radio wave is confirmed. If the detected air pressure is equal to or lower than the low pressure threshold, the TPMS receiver 12 displays on the display unit 16 together with the tire position that the tire air pressure is low. The TPMS receiver 12 performs this air pressure determination for each received radio wave Sva (valve ID) and monitors the air pressure of the tires 2a to 2d.

  The tire pressure monitoring system 3 is a so-called auto location function (tire position registration system 17) that automatically registers the tire IDs of the tire valves 4a to 4d in the TPMS receiver 12 in association with the tire positions. Is provided. The tire position registration system 17 transmits the radio wave Sva including the valve ID from the tire valves 4a to 4d at a specific position in the tire rotation direction, and the four-wheel axle 18 (18a to 18d) when the radio wave Sva is received by the vehicle body 5. ) Rotation position (rotation amount). The tire position registration system 17 performs this operation a plurality of times, and then checks which valve ID is synchronized with which of the axles 18a to 18d, thereby associating the valve ID with the axles 18a to 18d. To determine the positions of the tires 2a to 2d.

  As shown in FIG. 2, the tire valve 4 detects the gravity generated in itself based on the gravity signal of the gravity detector 9, and transmits the radio wave Sva at the peak position in the tire rotation direction as the specific position. The peak position may be, for example, “12 o'clock position” in the tire rotation direction. In the tire position registration system 17, transmitting the radio wave Sva when the tire valve 4 takes the peak position is one condition for the operation for determining the tire position. The radio wave Sva used for determining the tire position may be the same as the radio wave used when monitoring the tire pressure, or may be another type of radio wave. The valve ID of the right front tire valve 4a is “valve ID1”, the valve ID of the left front tire valve 4b is “valve ID2”, the valve ID of the right rear tire valve 4c is “valve ID3”, and the left rear tire valve 4d. The valve ID is “valve ID4”.

  Returning to FIG. 1, when the tire valve 4 takes a specific position in the axle rotation information Dc input from the axle rotation detection unit 19 (19 a to 19 d) provided on each axle 18 a to 18 d, the tire position registration system 17. The information acquisition part 20 which acquires a corresponding value is provided. The information acquisition unit 20 is provided in the tire pressure monitoring ECU 13. The information acquisition unit 20 receives the radio wave Sva (each valve ID) transmitted when the tire valve 4 takes a specific position (for example, a peak position) from the axle rotation detection unit 19 when the TPMS receiver 12 receives the radio wave Sva. In the output axle rotation information Dc, a value corresponding to the specific position is acquired. The information acquisition unit 20 measures the axle rotation information Dc of each axle 18 a to 18 d by the counter 21. A total of 16 counters 21 are provided for each of the four axles 18a to 18d and for each of the four-wheel valve IDs.

  The axle rotation detection units 19a to 19d may be, for example, ABS (Antilock Brake System) sensors provided on the axles 18a to 18d. In this case, the axle rotation information Dc may be the number of pulses detected by the ABS sensor, that is, a pulse count value. The axle rotation detection units 19a to 19d detect, for example, a plurality of (for example, 48) teeth provided on the respective axles 18a to 18d by the sensing unit on the vehicle body 5 side, so that the axle rotation information Dc has a rectangular wave shape. The pulse signal is output to the TPMS receiver 12. If the information acquisition unit 20 detects both the rising edge and the falling edge of the input pulse signal, the information acquisition unit 20 detects 96 pulses (count value: 0 to 95) per tire rotation as the axle rotation information Dc.

  The tire position registration system 17 includes a position determination unit 22 that determines the attachment positions of the tires 2a to 2d by associating the valve IDs received from the tire valves 4a to 4d with the axles 18a to 18d. The position determination unit 22 is provided in the tire air pressure monitoring ECU 13. When the position determination unit 22 receives the radio wave Sva from the tire valves 4a to 4d, the position determination unit 22 resets the counter 21 of each axle 18a to 18d, and then measures the axle rotation information Dc of each axle 18a to 18d by the counter 21. Specifically, each time the position determination unit 22 receives each valve ID, the position determination unit 22 resets the counter 21 corresponding to the received valve ID. That is, when the valve ID 1 is received, the four counters 21 corresponding to the valve ID 1 are reset, and when the valve ID 2 is received, the four counters 21 corresponding to the valve ID 2 are reset. The four counters 21 are sequentially reset. The position determination unit 22 determines the attachment position of each tire 2a to 2d by confirming which count value Ct the received valve ID is associated with based on the count value Ct of the counter 21.

Next, operation | movement of the tire position registration system 17 is demonstrated using FIGS.
As shown in FIG. 2, the tire valve 4 cannot always transmit the radio wave Sva at the peak position in each transmission operation due to, for example, tolerance of radio wave transmission or vibration that may occur in the tire 2 during traveling. . That is, as indicated by the broken line in the figure, the radio wave Sva is transmitted from the tire valve 4 at the “1 o'clock position” in the tire rotation direction due to the tolerance of the radio transmission of the tire valve 4 and the rough road running. Sometimes. Thus, in reality, the tire valve 4 has an allowable range Ea that can be assumed to have been transmitted by radio waves.

  By the way, since the vehicle 1 runs on a curve during driving, the tires 2a to 2d are configured to rotate independently. Therefore, if the vehicle is driven for a certain period of time and runs on a curve, the axles 18a to 18d have different rotational speeds, the output pulses of the axle rotation detectors 19a to 19d should take different values. Accordingly, if the valve ID and the axle 18 form a pair after traveling for a certain time, the axle rotation information Dc (count value Ct) falls within the allowable range Ea, and if different combinations, the axle rotation information Dc (count value Ct) ) Is likely to deviate from the allowable range Ea. In this example, the tire position is determined using this principle.

  Specifically, the position determination unit 22 of this example is based on the axle rotation information Dc acquired by the information acquisition unit 20 when receiving the radio wave Sva transmitted when the tire valve 4 is at the specific position (peak position). Then, it is confirmed whether or not the axle rotation information Dc (count value Ct) falls within the allowable range Ea with the reference point Pa as the center (middle point) corresponding to the timing at which the tire valve 4 transmits the radio wave. And the position determination part 22 performs this confirmation whenever the TPMS receiver 12 receives the electromagnetic wave Sva from the tire valve 4, and determines a tire position. The allowable range Ea is set in a range that takes into account the tolerance of the tire valve 4 and the vibration that can occur in the tire 2 during traveling (during rough road traveling). The reference point Pa does not necessarily correspond to the peak position, but corresponds to a midpoint when taking into account the amount of radio wave transmission timing deviation.

  As shown in FIG. 3, when the vehicle 1 accelerates on a paved road with a flat road, the gravity signal (gravity data), which is the output of the gravity detector 9, is sinusoidal as the vehicle 1 accelerates. Ascending to the right while climbing the wave changes. At this time, while maintaining the relationship that the amplitude change of the gravity data falls within the range of ± 1 G, the sine wave block itself rises, so that the gravity peak itself can be detected. However, when traveling on a rough road (constant speed in the figure), a steep change occurs in the sine wave, which hinders accurate determination of the peak. Therefore, as can be seen from the figure, the tire valve 4 is currently transmitting radio waves at different positions due to tolerances and vibrations, so that the tire position can be correctly determined without being affected by this. There is a need.

  As shown in FIG. 4, when receiving the radio wave Sva (valve ID) from the tire valve 4, the information acquisition unit 20 resets all the counters 21 (21a to 21d) associated with the axles 18a to 18d, and then The counter 21 (21a to 21d) counts the axle rotation information Dc of each axle rotation detection unit 19a to 19d, that is, the number of output pulses of each axle rotation detection unit 19a to 19d. As illustrated in the figure, if a tire valve 4a of “valve ID1” is attached to the right front axle 18a, the count value Ct-a of the right front axle 18a when the valve ID1 is received is It is an integral multiple of “96” which is the maximum value of the counter 21 (96 × n: n is an integer). On the other hand, when the vehicle 1 travels in a curve, the rotational position of each tire 2 takes a different amount. Therefore, the count value Ct of the other wheels (left front axle 18b, right rear axle 18c, left rear axle 18d) other than the right front axle 18a. -B, Ct-c, and Ct-d are more likely not to be an integral multiple of "96". Based on this idea, if it is determined which of the count values Ct-a to Ct-d when the valve ID is received is an integral multiple of "96", the axles 18a to 18d and the valve ID Can be linked. That is, the count values Ct-a to Ct-d are modulo calculated, and the tire position is determined based on the calculated value. As described above, in this example, whether or not the count values Ct-a to Ct-d at the time of receiving the valve ID are within the allowable range Ea is confirmed by modulo calculation.

  FIG. 5 illustrates an example of a modulo calculation result of the valve ID and the axle 18 forming a pair. The position determination unit 22 uses the maximum count number Ct-max, which is the maximum value of the counter 21 per one rotation of the tire, and the divisor Ddi obtained by factoring the maximum count number Ct-max, respectively. A modulo calculation is performed on the count value Ct of each of the axle rotation detection units 19a to 19d acquired when the valve ID is received. In this example, the maximum count number Ct-max is “96”. Further, when the maximum count number Ct−max is factorized, “96 = 3 × 2 × 2 × 2 × 2 × 2” is obtained, so that the divisor Ddi is “2, 4, 6, 8, 12, 16, 24”. , 32, 48 ". In the case of this example, the divisor Ddi is a binary value of, for example, “32” and “48”. The divisor Ddi used for the modulo calculation is not limited to a plurality, and may be only one.

  The reset value Ct-0 of the counter 21 is set to “½” of the smallest divisor when performing modulo calculation using a plurality of divisors Ddi. When the divisor Ddi is “32” or “48”, ½ of “32” which is a small value, that is, “16” is set as the reset value Ct-0. When the divisor Ddi is 1, the reset value Ct-0 is set to a value that is ½ of the divisor Ddi. If the count value Ct obtained by starting the reset value Ct-0 satisfying this relationship is modulo calculated, even if the tire valve 4 has a radio transmission tolerance, the tire valve 4 will also vibrate. However, when the modulo calculation is performed using any one of “96”, “48”, and “32”, the calculation results are congruent.

  For example, in the numerical example of the first row shown in FIG. 5, when the tire 2 rotates 79 times, 79 × 96 = 7584 pulses (count value Ct: 7584). When the valve ID is received, the counter 21 is reset to “16”, so that 7584 + 16 = 7600 is calculated modulo, and all the calculation results are “16”. A similar calculation is performed each time a valve ID is received.

  FIG. 6 illustrates an example of the modulo calculation result of the valve ID and the axle 18 that do not form a pair. Here, the count value Ct is arbitrarily taken and is a calculation result obtained by modulo calculation. Taking the count value Ct arbitrarily is synonymous with performing modulo calculation with the count value Ct not corresponding to the received valve ID. As can be seen from the figure, when the modulo calculation is performed with the valve ID and the axle 18 that do not form a set, all the values may be different or may coincide with each other by chance. At this time, if all the values are different, it can be considered that the valve ID and the axle 18 do not form a set.

  The probability that the modulo calculation results coincide by chance is set by a “ratio” between the divisor Ddi having the smallest value and the maximum count number Ct−max that is the maximum value of the counter 21 per one rotation of the tire. In this example, since the smallest divisor Ddi is “32” and the maximum count number Ct−max is “96”, the probability is “32/96 = 1/3”. However, even if the modulo calculation results coincide by chance, the tire position can be identified by repeating the determination by receiving the valve ID several times.

  FIG. 7 illustrates an example when the modulo calculation is executed a plurality of times. In this figure, when the count value Ct is modulo-calculated, the calculation result is “1” when the maximum count number Ct−max and the divisor Ddi are both modulo, and the case where the calculation result is not congruent. “0”. Further, the valve ID1 is the right front tire 2a, the valve ID2 is the left front tire 2b, the valve ID3 is the right rear tire 2c, the valve ID4 is the left rear tire 2d, and the modulo calculation is performed “10 times”.

  In the valve ID 1, the FR column of the right front axle 18 a is all “1”, but the FL, RR, and RL columns of the axles 18 b to 18 d of the other wheels are “1” instead of “0” with a probability of 1/3. It turns out that it becomes. Similarly, the valve ID2 is “1” with a probability of 1/3 in the other FR, RR, and RL columns where the FL column of the left front axle 18b is “1”, and the valve ID3 is RR of the right rear axle 18c. Other FR, FL, and RL fields that are all “1” are “1” with a probability of 1/3, and valve ID 4 is other than those that are all “1” in the RL field of the left rear axle 18d. The FR, FL, and RR fields are “1” with a probability of 1/3. For example, if only the modulo calculation result of the valve ID1 is viewed to identify the valve ID1, the right front axle 18a and the left rear axle 18d continue to take "1" until the first to sixth calculations. It takes time to distinguish the two wheels. In addition, if the valve ID 3 is identified simply by looking only at the modulo calculation result of the valve ID 3, the left front axle 18b and the right rear axle 18c continue to take "1" until the first to third calculations. It takes time to distinguish the two wheels.

  However, in associating the valve ID with the axles 18a to 18d, the tire position can be identified at an earlier stage if the combinations are narrowed down while taking into consideration the determination result of the other wheel (other valve ID). Can do. In the case of this example, as highlighted in the frame F1 in the figure, the valve ID2 is “1” only in the left front axle 18b at the time of the second modulo calculation. The association between ID2 and the left front axle 18b can be confirmed. Further, as highlighted in the frame F2 in the figure, the valve ID 4 also becomes “1” only in the left rear axle 18d at the time of the second modulo calculation. The association of the left rear axle 18d can be confirmed.

  Therefore, when the positions of the valve ID1 and the valve ID3 are determined, the determination results of the valve ID1 and the valve ID3 can be determined at an early stage by using the determination results of the valve ID2 and the valve ID4. Specifically, in the first modulo calculation result of the valve ID1, the right front axle 18a and the left rear axle 18d are “1”, but at the end of the second modulo calculation, the left rear axle 18d has a valve ID4. Therefore, the right front axle 18a can be linked to the valve ID1 by the erasing method. Further, the modulo calculation result of the valve ID 3 is “1” in the right front axle 18a, the left front axle 18b, and the right rear axle 18c in both the first time and the second time, but as described above, the right front axle 18a. Since the valve ID1 and the left front axle 18b are determined to be the valve ID2, the right rear axle 18c can be linked to the valve ID3 by the erasing method. As described above, the tire positions of the four wheels can be determined only by transmitting the radio wave Sva from the tire valve 4 twice, that is, by only having one set of the radio wave Sva.

  As shown in FIG. 8, the modulo calculation of the count value Ct when the valve ID is received by using “96”, “48”, and “32” as a modulus is geometrically in the tire rotation direction. With respect to the true position (for example, peak position) of the tire valve 4, the radio wave Sva is within an allowable range Ea (within a predetermined angle range) that is uniquely determined from the tolerance of radio wave transmission of the tire valve 4 and the vibration of the vehicle 1. It is synonymous with determining whether or not it has been received. Based on this idea, when the reset value Ct-0 is “16”, the radio wave transmission tolerance of the tire valve 4 and the vibration of the vehicle 1 are within an allowable range Ea of “± 16” centered on “16”. If it is within the range, when the combination of the valve ID and the axle 18 is correct, the hatched portion in the figure can receive the radio wave Sva.

  As shown in FIG. 9, for example, when modulo calculation is performed using “16” having a value smaller than “32” as a modulus, the reset value of the counter 21 is set to “8”. If the vehicle 1 travels on a flat pavement or the like, and the tolerance of radio transmission of the tire valve 4 and the vibration of the vehicle 1 are within the allowable range Eb (<Ea) “16”, then “96”. The modulo calculation modulo and the modulo calculation modulo “16” are always congruent. That is, if the radio wave transmission tolerance and the vibration of the vehicle 1 are within the hatched portion of the figure, the modulo calculation always has the same calculation result. If the divisor Ddi can be reduced, the judgment becomes severe, which is advantageous for securing the judgment system.

  By the way, when the modulo calculation is performed using “16” as a modulo, a narrow allowable range Eb is obtained. In modulo calculation modulo “16”, a situation occurs in which the calculation results do not match. As a specific example, the “point a” moved by “24” in the clockwise direction from “8” of the reset value Ct-0 will be considered. Since the point a falls within the allowable range Ea in FIG. 8, the modulo calculation using the modulo “32” described above is the same as the modulo calculation using the modulo “96”. On the other hand, when the point a is modulo calculated with “16” modulo, it is out of the allowable range Eb. Therefore, the modulo calculation with “32” modulo and “16” modulo is congruent. Not. That is, the modulo calculation that is the same in the method of “32” does not match the modulo calculation in the method of “16”.

  Here, when FIG. 9 is verified, the modulo calculation modulo “16” can be viewed as if the mass of the allowable range Eb moves from A → B → C → D → E → F in terms of geometry. be able to. When the modulo calculation is “16”, the calculation result is different from the modulo calculation when the modulo is “32”. However, when looking at FIG. It is in the cell B located next to A, and it cannot be said that it is separated from the cell A in the hatched part. That is, this means that although the modulo calculation did not match, there was not much deviation in the timing of radio wave transmission. In this example, based on this situation, the tire position may be determined while weighting the modulo calculation result.

  FIG. 10 illustrates a specific example of the weighting process. The position determination unit 22 uses the calculation result for each axle 18a to 18d in the modulo calculation executed for each axle 18a to 18d triggered by the reception of the valve ID for the calculation result for each axle 18a to 18d. Weighting is performed based on the characteristic value α derived from a plurality of legal values, and the tire position is determined based on the weighting result. In this example, the characteristic value α is obtained by dividing the modulo calculation result of the count value Ct modulo “96” by “16” which is a divisor Ddi of “96”, and rounding off the decimal part of the result of division. The integer is a value obtained by modulo calculation with “6” which is a value obtained by dividing “96” by “16”. The characteristic value α is assigned to each of the squares A to E shown in FIG.

  Specifically, when the calculation result of the modulo calculation modulo “96” is “0 to 15” and the calculation result of the modulo calculation modulo “16” is “0 to 15”, The value α becomes “0”. Thereafter, the calculation result of the modulo calculation modulo “16” is “0 to 15”, and when the calculation result of the modulo calculation modulo “96” is “16 to 31”, the characteristic value α is “ When the calculation result of the modulo calculation modulo “96” is “32 to 47”, the characteristic value α is “2”, and the calculation result of the modulo calculation modulo “96” is “48 to When the value is 63, the characteristic value α is “3”, and when the calculation result of the modulo calculation using “96” as a modulus is “64 to 79”, the characteristic value α is “4” and “96” is a modulus. When the calculation result of the modulo calculation is “80 to 95”, the characteristic value α is “5”. Incidentally, the point a shown in FIG. 9 is set to a location highlighted in the frame F3 in FIG. 10, that is, the characteristic value α is “1”.

The position determination unit 22 weights the calculation result of the modulo calculation based on the calculated characteristic value α. Specific examples of weighting are as follows.
(I) When α = 0, “+2 points”
(II) When α = 1, 5, “+1 point”
(III) When α = 2, 4, “−1 point”
(IV) When α = 3, “−2 points”
In this way, the position determination unit 22 calculates the weighting score for the calculation result of the modulo calculation, and when the total of the weighting score is larger than the other wheel by a predetermined amount, or when the weighted sum is equal to or greater than the threshold value. , Confirm the combination. When position determination is completed for all four wheels, the position determination unit 22 writes the determination result in the memory 15 and updates the tire position. The tire position determination process may be executed each time the ignition switch of the vehicle 1 is turned on, for example.

According to the configuration of the present embodiment, the following effects can be obtained.
(1) When the radio wave Sva (valve ID) transmitted from the tire valve 4 is received by the TPMS receiver 12, the axle rotation information Dc (count value Ct) of each of the axles 18a to 18d is acquired, and the maximum count number is obtained. Modulo calculation is carried out using Ct-max “96” and divisors Ddi “32” and “48” respectively. Then, among the axles 18a to 18d, valve IDs are linked to those for which the calculation results of the modulo calculation are congruent, and this is performed for each valve ID to specify the tire positions of the four wheels. In the case of this example, the tire position is confirmed every time radio waves are received (valve ID), and this confirmation can be repeated until the tire positions of all wheels can be identified. It is possible to end the tire position determination process. For this reason, in determining the tire position, it is not necessary to collect information necessary for position determination over a certain period of time in advance. Therefore, the tire position can be determined and registered in the TPMS receiver 12 in a short time.

  (2) The permissible ranges Ea and Eb are set in a range that takes into account tolerances in transmission of radio waves from the tire valve 4 and vibrations that can occur in the tire 2 when the vehicle 1 travels. Therefore, the permissible ranges Ea and Eb can be set in the optimum range required for the actual tire position determination.

  (3) Modulo calculation is used to determine the tire position, that is, to confirm the valve ID and the tying of the axle 18. Therefore, the tire position can be specified by a simple calculation called modulo calculation (division).

  (4) When the counter 21 is reset, a half value of the smallest value in the divisor Ddi used for the modulo calculation is set as the reset value Ct-0. Therefore, when confirming the association between the valve ID and the axle 18 by modulo calculation, the calculation results of the modulo calculation can be made to coincide with each other in the valve ID and the axle 18 that form a pair.

  (5) When checking the association between the valve ID and the axle 18 by modulo calculation, the calculation result (congruent or non-congruent) is weighted, and the association between the two parties is confirmed based on the weighted result. Therefore, for example, even if the axle rotation information Dc (count value Ct) may deviate from the allowable ranges Ea and Eb due to sudden vibration of the vehicle body 5 or the like, the information acquired at this time is wasted. And can be used to determine the tire position. This is also advantageous for finishing the tire position determination early.

  (6) In confirming the association between the valve ID and the axle 18, the combination is narrowed down while taking into consideration the determination result of the other wheel. Therefore, since it is possible to efficiently narrow down the association between the valve ID and the axle 18, it is further advantageous to complete the tire position in a short time.

The embodiment is not limited to the configuration so far, and may be changed to the following modes.
As shown in FIG. 11, the modulo calculation is not limited to being executed every time the radio wave Sva (valve ID) is received by the TPMS receiver 12. As shown by the white arrow in the figure, after the previous linking confirmation determination (modulo calculation) is performed, the next determination is executed after waiting for the reception of the radio wave Sva a prescribed number (several times). The determination of the association confirmation may be executed at an interval where the reception of the radio wave Sva is performed a predetermined number of times. As described above, if the modulo calculation is performed with a plurality of radio wave receptions, a difference between the four wheels is likely to occur when comparing the modulo calculation results. Therefore, it is further advantageous to complete the tire position early.

  When weighting the modulo calculation result, for example, the weighting process may be executed only when it is detected that a large vibration is generated in the vehicle 1. In this case, the vehicle 1 is provided with, for example, a vehicle body vibration detection unit (for example, an acceleration sensor) that detects vibration generated in the vehicle 1, and weighting is performed when a large shake of the vehicle body 5 is detected by the vehicle body vibration detection unit. Enable the calculation of. In this way, the weighting process can be executed only when necessary.

The determination as to whether or not the vehicle is traveling on a rough road may be determined as traveling on a rough road when none of the axles 18a to 18d becomes “1” (see FIG. 7), for example, in modulo calculation.
The characteristic value α used for weighting is not limited to a value obtained from the calculation method described in the embodiment, but may be changed to a value calculated using another calculation method.

-The weighting process can be omitted.
The tire position determination process (auto-location) may be performed all the time, or a certain time zone may be determined and executed only during that time zone.

-The same radio wave may be used for the air pressure for monitoring tire pressure and the auto location radio wave, or different types of radio waves may be used.
The tire valve 4 may transmit the radio wave Sva at both upper and lower peak positions (“12 o'clock position” and “6 o'clock position”).

The specific position is not limited to the peak position, and may be a predetermined position in the tire rotation direction.
The axle rotation detection unit 19 may transmit a detection signal to the TPMS receiver 12 wirelessly.

The axle rotation detection unit 19 may use a sensor other than the ABS sensor.
The total number of pulses of the axle rotation detection unit 19 is not limited to “96” and can be changed to other values. The number of pulses is not limited to an even number and may be an odd number.

The axle rotation information Dc is not limited to the number of detected pulse signals (number of pulses), and may be a parameter corresponding to the rotation position (rotation amount) of the axle 18.
The tire 2 that is a position determination target may include a spare tire.

The permissible ranges Ea and Eb can be set as appropriate within the actually required range.
The gravity detection unit 9 can use a sensor other than the G sensor.
The reset value Ct-0 is not limited to a value that is 1/2 of the smallest divisor Ddi, and may be a value in the vicinity thereof.

  The tire position determination method is not limited to a method using modulo calculation, and as described in the embodiment, it is confirmed whether the count value Ct is geometrically within the allowable ranges Ea and Eb. Any method can be used.

  DESCRIPTION OF SYMBOLS 1 ... Vehicle, 2 (2a-2d) ... Tire, 3 ... Tire pressure monitoring system, 4 (4a-4d) ... Tire valve, 5 ... Vehicle body, 12 ... Receiver (TPMS receiver), 18 (18a-18d) ... Axle, 19 (19a-19d) ... Axle rotation detection unit, 20 ... Information acquisition unit, 21 ... Counter, 22 ... Position determination unit, Sva ... Radio wave, ID1-ID4 ... Valve ID, Dc ... Axle rotation information, Ea, Eb: allowable range, Pa: reference point, Ct: count value, Ct-max: maximum count number, Ddi: divisor, Ct-0: reset value, α: characteristic value.

Claims (7)

Necessary for transmitting a radio wave including tire pressure data from the tire valve of each tire and receiving the radio wave with a receiver of the vehicle body to monitor the pressure of each tire, and the tire valve ID corresponds to the tire position In addition, in the tire position registration system for registering in the receiver,
Corresponding to the specific position in the axle rotation information output from the axle rotation detection unit provided on each axle, when the receiver receives a radio wave transmitted when the tire valve takes the specific position. An information acquisition unit for acquiring values;
When the radio wave is received from the tire valve and the axle rotation information for the valve ID is acquired, the value of the axle rotation information is within an allowable range centered on a reference point corresponding to the timing at which the tire valve transmits the radio wave. And a position determination unit that determines whether the tire position is determined by linking the valve ID and the axle by performing the confirmation every time the radio wave is received, Tire position registration system. 2. The tire position registration system according to claim 1, wherein the allowable range is set to a range that takes into account a tolerance in radio transmission of the tire valve and vibration that may occur in the tire during traveling. The information acquisition unit measures the axle rotation information with a counter,
The position determination unit has acquired the maximum count number that is the maximum value of the counter when the tire makes one rotation and the divisor obtained by factoring the maximum count number, respectively, as a modulus. 3. The tire position registration according to claim 1 or 2, wherein a modulo calculation of a count value as axle rotation information is performed, and which valve ID is linked to which axle is based on the calculation result. system. The position determination unit, when counting the axle rotation information by the counter in the modulo calculation, performs counting by the counter with a half value of the divisor or a value in the vicinity thereof as a reset value. Item 4. The tire position registration system according to Item 3. The position determination unit weights the calculation result for each axle, which is either congruent or non-congruent in the modulo calculation, based on characteristic values derived from a plurality of modulo values used in the modulo calculation. The tire position registration system according to claim 3 or 4, wherein the tire position is determined based on the weighted result. The said position determination part narrows down a combination, taking into consideration the determination result of another wheel, when connecting valve ID and axle of each tire. The tire position registration system according to one item. The position determination unit performs the determination to determine whether the axle rotation information is within the allowable range, and then performs the next determination after waiting for reception of the radio wave a predetermined number of times. The tire position registration system according to any one of claims 1 to 6, wherein reception of radio waves is executed at regular intervals.