JP2016078481A - Tire position registration system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tire position registration system which determines a tire position in a short time, and can register it in a receiver.SOLUTION: An absolute value distance calculation part 21 resets counters 20a to 20d at ignition-on, and starts the measurement of the axle rotation information Dc of axles 18a to 18d on the basis of outputs of axle rotation detection parts 19a to 19d. The absolute value distance calculation part 21 acquires absolute values α of the axle rotation information Dc with one rotation of a tire as one cycle at each axle 18a to 18d on the basis of the axle rotation information Dc of the axles 18a to 18d, and calculates a plurality of absolute value distances αr by acquiring a difference between and among all the absolute values α by using all cases of combinations of valves ID1 to ID4 and the axles 18a to 18d. A position determination part 22 calculates an absolute value distance difference αs being a difference of the current absolute value distances αr and the past absolute value distances αr at the reception of a certain valve ID, performs the calculation at each re-reception of the valve ID, and determines a tire position on the basis of each absolute value distance difference αs.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-described problems is a gravitational force detection unit for each tire valve when monitoring the air pressure of each tire by transmitting a radio wave including tire air pressure data from the tire valve of each tire to the receiver of the vehicle body. Each time a radio wave is transmitted at a specific position in the tire rotation direction from each tire valve based on the detection signal, and the radio wave is received by the receiver, the specific rotation is detected from the axle rotation detection unit of each axle. Each axle measured by a counter with a certain timing as a starting point in the configuration for determining the tire position by obtaining the axle rotation information corresponding to the position and linking the valve ID and the axle from the tendency of the axle rotation information. Based on the axle rotation information, the absolute value of the axle rotation information with one rotation of the tire as one cycle is obtained for each axle, and the valve ID and axle A plurality of absolute value distances are calculated by obtaining differences between absolute values in all combinations, and an absolute value distance calculation unit that executes the above calculation every time the valve ID is received, and reception of a certain valve ID. At this time, a plurality of absolute value distance differences are calculated by obtaining a difference between a plurality of absolute value distances obtained now and a plurality of absolute value distances obtained at the time of receiving the same ID in the past for each pair. This calculation is performed each time each valve ID is re-received, and a position determination unit that determines the tire position from each obtained absolute value distance difference is provided.

  According to this configuration, if at least two sets of absolute value distance difference data groups obtained each time each valve ID is received, the tire position can be determined by acquiring at least two sets. 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, the position determination unit calculates a total value by adding a plurality of the absolute value distance differences obtained, and the total value is the highest among all combinations of the valve ID and the axle. Preferably, the small combination is identified as the correct combination of valve ID and axle. According to this configuration, even if there is a tolerance in the timing of radio transmission of the tire valve, it is possible to specify the tire position by a method in which the absolute value distance is added and the total value is calculated and determined. It becomes.

  In the tire position registration system, when there are a plurality of combinations in which the total value is the same or equal to or less than a certain value, the position determination unit sets these as candidates for a correct combination, and repeats calculation thereafter from among these candidates. It is preferable to narrow down the combination having the smallest total value obtained as described above as the correct combination of the valve ID and the axle. According to this configuration, in calculating the total value, even if a plurality of combinations having the same total value or less than a certain value remain, they can be identified and a final tire position determination result can be derived. It becomes possible.

  In the tire position registration system, the position determination unit, among all the combinations, the combination having the total value that exceeds the theoretical maximum value according to the tolerance of radio wave transmission that the tire valve has, It is preferable to narrow down candidates by removing them from the correct combination candidates. According to this configuration, it is possible to appropriately exclude combinations that are assumed to be inappropriate among all combinations, which is advantageous in efficiently determining the tire position.

  In the tire position registration system, the position determination unit is a combination having the absolute value distance difference deviating from an allowable value that can be obtained in accordance with a radio wave transmission tolerance of the tire valve among all combinations. Preferably, candidates are narrowed down by removing them from the correct combination candidates. According to this configuration, it is possible to appropriately exclude combinations that are assumed to be inappropriate among all combinations, which is advantageous in efficiently determining the tire position.

  In the tire position registration system, it is preferable that the counter is reset when a vehicle power source is in an ignition-on state. According to this configuration, it is possible to reset the counter at an optimal timing of ignition on, which is further advantageous for more correctly determining the tire position.

  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 conceptual diagram which shows the electromagnetic wave transmission timing of a tire valve. (A) is a conceptual diagram which shows the reset timing of a counter, (b) is a conceptual diagram which shows the value taken when a counter is t1. A table summarizing absolute values obtained when each valve ID is received. Explanatory drawing which shows the concept of the concept of tire position determination. A table summarizing the absolute distance differences obtained when there is no tolerance in the tire valve. A table summarizing the absolute distance differences obtained when there is tolerance in the tire valve.

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 4d. 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 tire valve 4 actually has a “tolerance” at the radio wave transmission position (radio wave transmission timing), and the radio wave Sva cannot always be accurately transmitted at the peak position. It varies.

  In this example, 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 The valve ID of the tire valve 4d is “valve ID4”. 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 radio wave Sva does not need to be transmitted at a specific position for each tire rotation, and may be transmitted at the first specific position after a certain period of time, for example.

  Returning to FIG. 1, the TPMS receiver 12 responds when the tire valve 4 takes a specific position in the axle rotation information Dc input from the axle rotation detection unit 19 (19a to 19d) provided on each axle 18a to 18d. Get the value to be. More specifically, the TPMS receiver 12 receives the radio wave Sva (each valve ID) transmitted when the tire valve 4 takes a specific position (for example, a peak position). The value corresponding to the specific position is acquired in the axle rotation information Dc output from The TPMS receiver 12 measures the axle rotation information Dc of each axle 18a to 18d by the counter 20. A total of four counters 20 of 20a to 20d are provided for each of the four axles 18a to 18d.

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

  The tire position registration system 17 calculates an absolute value distance αr necessary for tire position determination based on axle rotation information Dc input from axle rotation detection units 19a to 19d provided on the axles 18a to 18d. A distance calculation unit 21 is provided. The absolute value distance calculation unit 21 is provided in the tire air pressure monitoring ECU 13. The absolute value distance calculation unit 21 calculates the absolute value α of the axle rotation information Dc with one rotation of the tire as one cycle based on the axle rotation information Dc of each axle 18a to 18d measured by the counter 20 with a certain timing as a starting point. A plurality of absolute value distances “αr” are calculated by obtaining the difference between all the absolute values α in all combinations of the valve IDs 1 to ID4 and the axles 18a to 18d. Then, the absolute value distance calculation unit 21 performs this calculation every time the valve ID is received again.

  The tire position registration system 17 includes a position determination unit 22 that determines a tire position by narrowing down a combination of a correct valve ID and an axle 18 from a plurality of absolute value distances αr. The position determination unit 22 is provided in the tire air pressure monitoring ECU 13. The position determination unit 22 makes a pair of, for example, a difference between a plurality of absolute value distances αr1 obtained at the time of receiving a certain valve ID and a plurality of absolute value distances αr0 obtained at the time of receiving the same ID in the past. A plurality of absolute value distance differences “αs” are calculated by obtaining for each. And the position determination part 22 performs this calculation whenever it receives each valve ID again, and determines a tire position based on each calculated absolute value distance difference αs.

Next, operation | movement of the tire position registration system 17 is demonstrated using FIGS.
As illustrated in FIG. 3A, the absolute value distance calculation unit 21 resets all the counters 20 (20 a to 20 d), for example, at a timing when the vehicle power supply is in an ignition-on state. That is, when the ignition switch of the vehicle 1 is turned on, the count values Ct of the four counters 20a to 20d are all set to “0”. And the absolute value distance calculation part 21 starts the pulse measurement of the axle shaft rotation information Dc from this time. The absolute value distance calculation unit 21 performs modulo calculation using “96” which is one cycle of the output of the axle rotation detection unit 19 as a modulus, and calculates the calculation result as “absolute value α of the counter 20”.

  As shown in FIG. 3B, for example, when T = “t1”, the right front tire valve 4a transmits the radio wave Sva, and the TPMS receiver 12 receives the valve ID1. At this time, for example, the absolute value α of the right front axle counter 20a becomes “39”, the absolute value α of the left front axle counter 20b becomes “7”, the absolute value α of the right rear axle counter 20c becomes “17”, and the left rear axle It is assumed that the absolute value α of the counter 20d becomes “48”.

  As shown in FIG. 4, thereafter, valve ID2 is received when “T = t2”, valve ID3 is received when “T = t3”, and valve ID4 is received when “T = t4”. Suppose that ID reception in this order is repeated at t5 to t8. As can be seen from the figure, the absolute values α of the counters 20a to 20d of the axles 18a to 18d and the received valve ID1 to valve ID4 are paired with each other. That is, when the valve ID1 is received, the absolute value α of the right front axle counter 20a is “39” every time, and when the valve ID2 is received, the absolute value α of the left front axle counter 20b is “86” every time and the valve ID3 is received. In this case, the absolute value α of the right rear axle counter 20c becomes “36” every time, and when the valve ID 4 is received, the absolute value α of the left rear axle counter 20d becomes “81” every time. Therefore, if such a change tendency of the absolute value α is used as a determination material, the axles 18a to 18d and the valve ID1 to valve ID4 should be able to be linked. In this example, the tire position is determined based on this principle.

  FIG. 6 shows a table summarizing the calculation method of the tire position determination. Considering all combinations of valve ID1 to valve ID4 and axles 18a to 18d, this is "24". Then, the position determination unit 22 calculates a plurality of absolute value distance differences αs necessary for position determination for all of these combinations, and derives which combination is correct using these absolute value distance differences αs as determination elements. The tire position is determined by brute force calculation.

  Hereinafter, the calculation procedure of the position determination will be described in detail. When the position determination unit 22 receives the valve ID, the position determination unit 22 calculates a difference (absolute value distance αr) between the absolute values α of the respective axle counters 20a to 20d, and executes this calculation every time the valve ID is received. For example, when the valve ID 1 is received at “t1”, the absolute value α of the right front axle counter 20a is “39”, the absolute value α of the left front axle counter 20b is “7”, and the absolute value α of the right rear axle counter 20c is “ 17 ”, the absolute value α of the left rear axle counter 20d is“ 48 ”.

  In the calculation of the “first way” column, the valve ID1 is set to the absolute value α1 of the right front axle counter 20a as can be seen from the fact that “α1: FR (1)” is written at the top of the table. It is tied. Similarly, the valve ID2 is stringed to the absolute value α2 of the left front axle counter 20b as “α2: FL (2)”, and the valve is set to the absolute value α3 of the right rear axle counter 20c as “α3: RR (3)”. As shown in “α4: RL (4)”, ID3 is associated with the valve ID4, which is associated with the absolute value α4 of the left rear axle counter 20d.

  In the calculation of the “first way” column, the absolute value distance “α1-α2” becomes “39-7≡32 (mod 96)”, and the absolute value distance “α1-α3” becomes “39-17≡22 (mod 96). The absolute value distance “α1-α4” becomes “39-48≡87 (mod 96)”, and the absolute value distances “α2-α3”, “α2-α4”, “α3-α4” are calculated in the same manner. . On the other hand, in the calculation of the “second way” column, the absolute value distance “α1-α2” becomes “39-7≡32 (mod 96)”, and the absolute value distance “α1-α3” becomes “39-48≡87 ( mod 96) ”, the absolute value distance“ α1-α4 ”becomes“ 39-17≡22 (mod 96) ”, and the absolute value distances“ α2-α3 ”,“ α2-α4 ”,“ α3-α4 ”are calculated in the same manner. Is done. Then, this calculation is executed in all 24 columns.

  The position determination unit 22 calculates the absolute value distance αr by performing a calculation similar to the calculation performed when the valve ID1 is received when the valve ID2 is “t2”. The position determination unit 22 performs the same calculation at “t3” when the valve ID3 is received and “t4” when the valve ID4 is received, thereby calculating the absolute value distance αr.

  Subsequently, the case of “T = t5” where the valve ID 1 is received again will be verified with reference to FIG. At “t5”, the absolute value α again becomes “39” in the right front axle counter 20a in which the combination of the valve ID and the axle 18 is correct. Therefore, at “t5”, the absolute value α of the right front axle counter 20a → “39” is used as it is, and the absolute value α other than the right front axle counter 20a at “t1” when the same valve ID1 was received in the past is used. If the absolute value distance αr is calculated using this, the calculation result is the same as that at “t1”. This is because “t1−t5” is calculated, that is, the difference between the value at “t1” and the value at “t5” in each of the six absolute distances “α1−α2” to “α3−α4” ( This is synonymous with determining whether the absolute distance difference αs is “0” or within an allowable range. In this example, the tire position is determined using this principle.

  Returning to FIG. 6, the position determination unit 22 is the difference between the absolute value distance αr1 at the time of “t5” and the absolute value distance αr0 obtained when the valve ID1 was received in the past when receiving the valve ID1. “t1-t5” is calculated for all combinations of “α1-α2” to “α3-α4”. Similarly, when the reception timing of the valve ID 2 is “t6”, the reception timing of the valve ID 3 is “t 7”, and the reception timing of the valve ID 4 is “t 8”, the absolute value distance difference is calculated by the same calculation. αs is calculated.

  In the first case, since this is an example of a correct combination, the absolute value distance difference αs calculated between “t5” and “t8” is both “0” or within an allowable range. For this reason, the position determination unit 22 confirms that the absolute value distance difference αs has a valid value, and therefore determines that the first combination is correct. That is, it is possible to determine that 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, and the valve ID4 is the left rear tire 2d. In this example, it is the time of receiving the same ID immediately before (for example, t1 and t5 in the case of ID1), but it is not necessarily the time immediately before. If it is above the same ID received in the past, ID may be sufficient.

  On the other hand, in the second case, as described in “α3: RL (4)”, the absolute value α3 of the right rear axle counter 20c is associated with the valve ID4, and as described in “α4: RR (3)”. It is assumed that the absolute value α4 of the left rear axle counter 20d is associated with the valve ID3. In this case, since it is assumed that the valve ID3 is attached to the left rear tire 2d and the valve ID4 is attached to the right rear tire 2c, the absolute value distance difference αs is partly other than “0”. In this example, the absolute value distance difference αs obtained by the calculation of “t3−t7” is partly other than “0”, and the absolute value distance difference αs obtained by the calculation of “t4−t8” is partly “0”. It becomes other than. For this reason, the position determination unit 22 determines that the second combination is not valid. By the same determination, it is determined that the third and subsequent combinations are not valid combinations.

  When “t1−t5” is calculated, the calculation result in which the absolute value distance difference αs is always “0” is obtained not only in the first way but also in the second to fifth ways, for example. This is because it is assumed that the valve ID1 is tied to the right front axle 18a in the first to fifth ways. Therefore, the absolute value distance difference αs of “t1−t5” is always “0” when the “valve ID1” that is the reception target ID at “t1” and “t5” forms a set now. It is also proved that it is linked to the assumed “right front axle 18a”, that is, that the tire valve 4a is paired with the right front axle 18a. Incidentally, in the second case, since the absolute value distance difference αs of “t2−t6” is always “0”, it is proved that the valve ID 2 and the left front axle 18b are linked.

  Note that just because the absolute value distance difference αs is always “0” does not necessarily prove that the combination is valid. Specifically, in the fifth “t2-t6”, the absolute value distance difference αs is always “0”, but the valve ID 4 is attached to the left front axle 18b, and the combination is not correct. This occurs if the order of rotation of the other three wheel assignments is not correct. However, even if such a phenomenon occurs, a correct determination result can be obtained if the determination is repeated and confirmed.

  The position determination unit 22 identifies the most suitable combination as a combination of the correct valve ID and the axle 18 by confirming the calculated absolute value distance difference αs in all combinations. And if the tire position can be specified, the position determination part 22 will write this in the memory 15, and will update a tire position. In addition, when the tire position cannot be determined by the position determination twice (2 sets), the tire position is determined by repeating the same processing thereafter (after the third set).

  FIG. 7 illustrates an example of a calculation result when a “deviation due to tolerance” occurs in the radio wave transmission timing of the tire valve 4. As described above, the tire valve 4 is not always capable of transmitting the radio wave Sva at the peak position every time, and there is a current state of transmitting the radio wave Sva at a transmission timing including a certain “tolerance”. Therefore, in fact, the tire valve 4 often transmits the radio wave Sva at a timing about a predetermined amount with respect to the peak position.

  In the case of the example in the figure, the absolute value α from “t1” to “t4” is the same as in FIG. 6, and the absolute value α of the right front axle counter 20a at “t5” is set to “11” from “39”. “28” which is earlier, the absolute value α of the left front axle counter 20b at “t6” is “93” which is “7” later than “86”, and the absolute value of the right rear axle counter 20c at “t7” α is “53” which is “17” later than “36”, and the absolute value α of the left rear axle counter 20d at “t8” is “93” which is “12” later than “81”.

  When the above-described “tolerance deviation” exists, when the valve ID 1 is calculated as “t1-t5” to be received, as a result, the tolerance “11” of the pair-positioned tire valve 4a is directly output as the absolute value distance difference αs. Come. Similarly, when calculating “t2−t6”, the tolerance “7” of the tire valve 4b paired with the valve ID2 appears, and when calculating “t3−t7”, the tolerance of the tire valve 4c paired with the valve ID3 is displayed. A tolerance “17” appears, and when calculating “t4−t8”, a tolerance “12” between the valve ID 4 and the tire valve 4d positioned as a pair appears.

  By the way, out of all the combinations, if the combination pattern is correct, the deviation amount of the absolute value distance difference αs is small. Conversely, if the combination pattern is wrong, the deviation amount of the absolute value distance difference αs should be large. It is. For this reason, for example, if the sum of the absolute value distance differences αs is taken and the total value Tα is small, it should be possible to determine that the combination is correct. Therefore, the position determination unit 22 calculates the total value Tα of the absolute value distance difference αs in each combination, and identifies the combination having the smallest total value Tα as the correct combination.

  Incidentally, in the case of FIG. 7, the same minimum value “141” is taken for the first combination from the left and the fourth combination from the left in the figure. In this way, when there are a plurality of the same total value Tα (or including a certain value or less), for example, a predetermined value is left as a combination candidate, and when the candidate appears repeatedly or becomes a predetermined value or less, the final value One set should be determined. The reason why the same total value Tα occurs by chance is that the absolute value α (number of pulses) should be different from the original, but the same value may happen by chance due to the “tolerance” of the transmission position of the tire valve 4. This is because.

  When the tolerance of the tire valve 4 is “25”, for example, if the combination is correct, the maximum tolerance of the total value Tα may fall within the theoretical maximum value “300 (= 25 × 3 × 4)”. high. Further, if the tolerance of the tire valve 4 is “25”, for example, when the combination is correct, there is a high possibility that any absolute value distance difference αs falls within the allowable value “25” which is the maximum tolerance. Therefore, if these combinations are taken into consideration and the combinations are narrowed down, it is advantageous to complete the tire position determination earlier.

According to the configuration of the present embodiment, the following effects can be obtained.
(1) When determining the tire position, it is possible to specify the tire position by acquiring at least two sets of data groups of the absolute value distance difference αs obtained each time the valve ID1 to valve ID4 are received. That is, if there are at least two sets of the data group of the absolute value distance difference αs from t1 to t4 and the data group of the absolute value distance difference αs from t5 to t8, the tire position can be determined. 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 TPMS receiver 12 in a short time.

  (2) In each combination, a plurality of absolute value distance differences αs are added to calculate the total value Tα, and the combination having the smallest total value Tα is specified as the correct combination of the valve ID and the axle 18. Therefore, even if there is a tolerance in the timing of radio wave transmission of the tire valve 4, the tire position can be specified by a method of calculating and determining the total value Tα by adding the absolute value distance difference αs. .

  (3) In calculating the total value Tα of the absolute value distance difference αs and specifying the tire position, when there are a plurality of combinations having the same total value Tα, these are set as candidates for the correct combination, and among these candidates, Thereafter, the combination having the smallest total value Tα obtained by repeating the calculation is narrowed down as the correct combination of the valve ID and the axle 18. Therefore, even if there are a plurality of the same total value Tα, it is possible to identify these and derive the final tire position determination result.

  (4) Of all the combinations, a combination having a total value Tα that exceeds the theoretical maximum value (one example is “300” described in the embodiment) according to the tolerance of radio wave transmission of the tire valve 4. Further, by excluding from the correct combination candidates, it is possible to determine whether to narrow down the candidates. Therefore, it is possible to appropriately exclude combinations that are assumed to be inappropriate from all combinations, which is advantageous for efficiently determining the tire position.

  (5) Among all combinations, by removing combinations that deviate from an allowable value according to the maximum tolerance of the tire valve 4 (an example is “25” described in the embodiment) from candidates for correct combinations, Judgment that narrows down can be taken. Therefore, it is possible to appropriately exclude combinations that are assumed to be inappropriate from all combinations, which is advantageous for efficiently determining the tire position.

  (6) When the ignition is turned on, the counter 20 is reset and measurement of the axle rotation information Dc is started. Therefore, it is possible to execute the measurement of the axle rotation information Dc based on the optimum timing of ignition on, which is more advantageous for more correctly determining the tire position.

Note that the embodiment is not limited to the configuration described so far, and may be modified as follows.
A predetermined (constant) time difference may be provided between the first set (calculation of t1 to t4) and the second set (calculation of t5 to t8). By doing so, a difference is easily generated in the axle rotation information Dc (number of pulses) in each wheel, which is advantageous in determining the tire position.

  ・ When collecting axle rotation information Dc for one set, even if a certain valve ID cannot be received and the absolute value α of the same ID is missing, the absolute value α is calculated for other received valve IDs. The processing for the absolute value distance difference αs may be calculated when the missing valve ID is acquired at the next timing.

The reset timing of the counter 20 is not limited to turning on the ignition, and can be appropriately changed to another timing.
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 gravity detection unit 9 can use a sensor other than the G sensor.

1 ... vehicle,
2 (2a to 2d) ... tyre, 3 ... tyre pressure monitoring system, 4 (4a to 4d) ... tyre valve, 5 ... vehicle body, 9 ... gravity detector, 12 ... receiver (TPMS receiver), 17 ... tyre position Registration system, 18 (18a-18d) ... Axle, 19 (19a-19d) ... Axle rotation detection unit, 20 (20a-20d) ... Counter, 21 ... Absolute value distance calculation unit, 22 ... Position determination unit, Sva ... Radio wave , Dc: axle rotation information, ID1 to ID4: valve ID, α: absolute value, αr: absolute value distance, αs: absolute value distance difference, Tα: total value.

Claims (6)

When monitoring the tire pressure by transmitting radio waves including tire pressure data from the tire valve of each tire to the receiver of the car body, the tire rotation from each tire valve based on the detection signal of the gravity detection part of each tire valve Each time the radio wave is transmitted at a specific position in the direction, and the radio wave is received by the receiver, the axle rotation information corresponding to the specific position is obtained from the axle rotation detection unit of each axle, In the tire position registration system for determining the tire position by associating the valve ID and the axle from the tendency of the axle rotation information,
Based on the axle rotation information of each axle measured by a counter at a certain timing, the absolute value of axle rotation information with one rotation of the tire as one cycle is obtained for each axle, and the valve ID and the whole axle are Calculating a plurality of absolute value distances by obtaining a difference between absolute values in combination, and an absolute value distance calculating unit that executes the above calculation every time the valve ID is received;
Multiple absolute values are obtained by determining, for each pair, the difference between a plurality of absolute value distances obtained at the time of receiving a valve ID and a plurality of absolute value distances obtained at the time of receiving the same ID in the past. A tire position registration system comprising: a distance determination unit, and a position determination unit that performs the calculation each time each valve ID is re-received and determines a tire position from each obtained absolute value distance difference . The position determination unit adds a plurality of obtained absolute value distance differences to calculate a total value, and among all combinations of the valve ID and the axle, the combination having the smallest total value is determined as the valve ID and The tire position registration system according to claim 1, wherein the tire position registration system is specified as a correct combination of axles. When there are a plurality of combinations in which the total value is the same or less than a certain value, the position determination unit sets these as candidates for a correct combination, and among these candidates, the total value obtained by repeating the calculation thereafter The tire position registration system according to claim 2, wherein a combination having the smallest value is narrowed down as a correct combination of a valve ID and an axle. The position determination unit excludes a combination having the total value that exceeds a theoretical maximum value in accordance with a radio wave transmission tolerance of the tire valve from all combinations, from candidates for a correct combination. 4. The tire position registration system according to claim 2, wherein candidates are narrowed down by going. The position determination unit, among all combinations, a combination having the absolute value distance difference that deviates from an allowable value that can be taken in accordance with the tolerance of radio wave transmission that the tire valve has, is selected as a correct combination candidate. The tire position registration system according to any one of claims 1 to 4, wherein candidates are narrowed down by removing them. The tire position registration system according to any one of claims 1 to 5, wherein the counter is reset when a vehicle power source is in an ignition-on state.