JPH1071819A - Tire abnormality detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain detailed information about not only the presence or absence of a tire abnormality occurrence in a vehicle but also a tire in which abnormality has occurred. SOLUTION: The device comprises rotation detecting means 3a to 3d which detect every passage of rotation detecting parts 21 formed on bodies of rotation 2a to 2d in the circumferential direction, the bodies of rotation 2a to 2d rotating together with tires 1a to 1d as one body, and an electronic control system 4 into which the detection signals obtained by the rotation detecting means 3a to 3d are inputted. The electronic control system 4 comprises an amount of shift dependent value computing means which computes an amount of shift dependent value which depends on the amount of shift of the frequency of the detection signals from the reference value, a feature variable computing means which computes a feature variable representing the feature of the computed amount of shift dependent value and a judging means which judges normality or abnormality of the condition of a tire with two values on the basis of the feature variable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tire abnormality detecting device for detecting an abnormality of a tire of a vehicle.

[0002]

2. Description of the Related Art A tire abnormality detecting device is a device for monitoring the condition of a tire during traveling and detecting an abnormality such as air leakage to notify a driver or the like of the abnormality. As the tire state detection technology, in addition to the conventionally known tire pressure and tire internal temperature detection, attention is paid to the fact that the tire radius changes when the tire deflates, and the wheel angular velocity is detected. There is something. Japanese Unexamined Patent Application Publication No. 4-232107 discloses a tire function detecting technique in which a linear function of a difference between squares of angular velocities of a first pair of wheels and a second pair of wheels is calculated. There is disclosed a method for detecting air deflation of a tire which is to be detected.

[0003]

However, according to the method for detecting air deflation of a tire described in Japanese Patent Application Laid-Open No. Hei 4-232107, the presence or absence of air deflation of a tire can be known from a linear function that inputs angular velocities of four wheels. It is not possible to obtain detailed information on a tire in which an abnormality has occurred, for example, whether the deflated tire is on the front side or the rear side.

Accordingly, an object of the present invention is to provide a tire abnormality detecting device capable of obtaining not only the presence / absence of tire abnormality but also detailed information on a tire in which abnormality has occurred.

[0005]

According to the first aspect of the present invention, the rotating body rotates integrally with the tire, and each time a rotation detecting section formed in the circumferential direction passes through the rotating body, the rotating body detects the rotation. Detecting means, a shift amount dependent value calculating means for calculating a shift amount dependent value of the period of the detection signal obtained by the rotation detecting means from the reference value, and characteristics of the calculated shift amount dependent value. Characteristic variable calculating means for calculating a characteristic variable indicating the following. The determining means performs a binary determination of the tire state based on the calculated characteristic variables.

Since the deviation amount dependent value is expressed based on the deviation amount of the period of the detection signal from the reference value, when an abnormality occurs in the tire, the tire abnormality is reflected on the deviation amount dependent value. When a tire abnormality occurs, the characteristic variables change greatly,
The tire abnormality is determined by the determination means. Therefore, data on all tires is not required to determine the presence or absence of a tire abnormality. Moreover, since the characteristic variables are variables corresponding to each tire, detailed information on the tire in which an abnormality has occurred can be obtained.

The characteristic variable can be easily calculated by setting the variation of the deviation dependent value in one rotation of the rotating body as described in claim 2 or the amount of change with time of the deviation dependent value as defined in claim 3. it can.

The determination means may be set so that the difference between the wheels of the characteristic variable is compared with a predetermined value as in claim 4, or the present value of the characteristic variable is compared with the previous value as in claim 5. May be set to be compared with a predetermined value. The difference between the current value and the initial value of the characteristic variable may be set to be compared with a predetermined value. in this case,
According to a seventh aspect of the present invention, the initial value of the characteristic variable may be a calculated value calculated by the characteristic variable calculating means when the tire is normal, and the determining means may include a storage means for storing the calculated value.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) FIG. 1 shows a tire abnormality detecting apparatus to which the present invention is applied. The tire abnormality detection device includes signal rotors 2a, 2b, 2c, and 2d as rotating bodies that rotate integrally with the tires 1a, 1b, 1c, and 1d of the vehicle,
Electromagnetic pickups 3a, 3b, 3 serving as rotation detecting means provided at positions close to the outer periphery of signal rotors 2a to 2d.
c, 3d. Each of the signal rotors 2a to 2d is a gear having a large number (48 in the present embodiment) of teeth 21 formed of a magnetic material in the circumferential direction and formed at regular intervals according to the standard. . The electromagnetic pickups 3a to 3d detect changes in the magnetic field of the signal rotors 2a to 2d that rotate integrally with the tires 1a to 1d due to the passage of one tooth. A sinusoidal detection signal is output.
Detection signals for the signal rotors 2a to 2d output from the electromagnetic pickups 3a to 3d are input to an electronic control unit (ECU) 4.

The ECU 4 includes a waveform shaping circuit to which a detection signal is input and a microcomputer to which an output from the waveform shaping circuit is input. The ECU 4 generates a sine-wave detection signal of each of the signal rotors 2a to 2d. The signal is shaped into a rectangular wave pulse signal by a shaping circuit and input to a microcomputer. The microcomputer calculates the rotational state of each of the signal rotors 2a to 2d from the pulse signal to determine whether or not there is a tire abnormality.

A display unit 5 is connected to the ECU 4, and when a tire abnormality is detected, the driver is notified of the abnormality by an indicator lamp or the like.

Note that the tire abnormality detecting device is provided for each of the tires 1a to 1a.
It also functions as a wheel speed detecting device that detects the wheel speed of 1d, and the calculation result of the rotation state of each of the signal rotors 2a to 2d is used for calculating the wheel speed of each of the tires 1a to 1d. Has been reduced.

FIG. 2 shows the state of the pulse signal input to the microcomputer of the ECU 4. In the microcomputer, in response to the falling edge of the pulse signal,
Using this as an interrupt signal, a vehicle speed pulse interrupt process is executed. In the microcomputer, the periodic interruption process is executed at times indicated by S1, S2,.

FIG. 3 shows the flow of the vehicle speed pulse interruption process. First, in step 1100, the period Δt _{n of the} pulse signal is measured. The pulse signal period Δt _n is obtained by calculating the interval (FIG. 2) of the falling part of the preceding and succeeding pulse signals that becomes an interrupt signal. In step 1200, a rotation detection unit number corresponding to each rotation detection unit is assigned to each pulse signal. The number of the rotation detection unit is defined by each of the signal rotors 2a to 2d.
The number of the tooth of the signal rotor, which is assigned from 1 to the maximum value of the number of teeth (48 in this embodiment). That is, 1, 2, 3,... 46, 47, 4
.. Corresponding to each rotation detection unit, such as 8, 1, 2,.
Repeat number 48.

Since the time required for the rotator to make one rotation is very small, the rotation speed during one rotation of the rotator can be regarded as a constant speed. Therefore, the 48 pulse signal periods in one rotation of the rotating body should be constant. However, in practice, deviations occur in the pulse signal cycle due to processing errors in the rotation detection units of the signal rotors 2a to 2d and nonstandard elements such as abnormal tires such as uneven wear and air leakage (see FIG. 4A). Therefore, a correction is made so that the deviation H between the average value of the 48 pulse signal periods and the pulse signal period of each rotation detecting unit approaches 0 (see FIG. 4B).

Steps 1300 and 1400 correspond to the signal period Δ
This is a procedure for updating a correction coefficient which is a shift amount dependent value for correcting a shift of t _n . As for the correction coefficient, in step 1300, it is determined whether the update of the correction coefficient ω _{n, m} is permitted. The subscript n is the number of the rotation detecting unit, and the correction coefficients ω _{n, m} correspond one-to-one with the rotation detecting units 21 of the signal rotors 2a to 2d. The subscript m is the number of rotations of the signal rotor, ω
_This shows that _{n and m-1} are correction coefficients before one rotation.
Here, the condition for updating the correction coefficient ω _{n, m} is that the latest 48 consecutive pulse signals are input without interruption in the regular interrupt section (FIG. 5A can be updated, and FIG. 5B cannot be updated). . Step 1400 is an operation as a deviation amount dependent value calculating means.

FIG. 6 shows a procedure for updating the correction coefficient ω _{n, m} in step 1400. In step 1410, the pulse signal period Δt _k (k = n−
48, n-47,... N-2, n-1),
From the read pulse signal period Δt _n, an average value S of 48 pulse signal periods corresponding to one rotation of the signal rotor is calculated by equation (1). The average value S of the pulse signal period becomes a reference value of the pulse signal period Δt _n including a detection error due to a non-standard element.

[0018]

(Equation 1)

[0019] In step 1420, calculates the deviation dependent value Delta] t _h by the equation (2). That is, the deviation between the pulse signal period average value S and the pulse signal period Δt _n of each rotation detector corrected by the previous correction coefficient ω _{n, m-1} is calculated (see the numerator in the equation (2)), and the deviation is calculated. In order to eliminate the speed dependence, the deviation is normalized by the average value S of the pulse signal period. Δt _h = (S−ω _{n, m−1} Δt _n ) / S (2)

[0020] deviation dependent value Δt _h is, the signal rotor 2a
It is considered that this indicates the amount of deviation of the pulse signal period of each of the rotation detection units from to 2d with respect to the reference value. However if indeed the vehicle has traveled the road, because the wheel speed by the vibration of the road surface which varies randomly indicates the character of the signal rotor 2a~2d in each rotation detector varies randomly every Delta] t _h also pulse signal input It cannot be a value. Therefore, in step 1430, applying a correction sensitivity coefficient k for adjusting the convergence rate of the correction coefficient omega _{n, m} to Δt _h (kΔ
t _h ), Δ Δ for one pulse signal input
The degree of influence of t _{h on} the correction coefficient ω _{n, m} is adjusted. For example, if the value of the correction sensitivity coefficient k is reduced _, the amount of change in the correction coefficient ω _{n, m} can be reduced. By this means, the random fluctuation of the wheel speed due to the road surface vibration is corrected by the correction coefficient ω _{n, m}
Can be eliminated.

[0021] The correction coefficient omega _{n, m} by using a value k.DELTA.t _h adjusted by the correction sensitivity coefficient k Step 1440 the deviation dependent value Delta] t _h is updated by equation (3). That is, kΔt
_h is added to the previous value ω _{n, m-1} of the correction coefficient of each rotation detection unit. Here, the initial value of the correction coefficient ω _{n, m} is 1. _{ω n, m = ω n,} m-1 + kΔt h ···· (3)

Each of the above formulas updates the correction coefficient ω _{n, m} corresponding to each rotation detection unit each time the rotation detection unit passes through the rotation detection units of the electromagnetic pickups 3a to 3d, This means that a correction coefficient convergence value capable of correcting an error due to a non-standard element corresponding to the rotation detection unit is obtained.

As described above, the correction coefficient is determined by the signal rotor 2
In addition to the processing errors a to 2d, the rotational states of the signal rotors 2a to 2d caused by air deflation of the tires 1a to 1d are reflected. Therefore, when a tire abnormality occurs, the correction coefficient has a larger variation per rotation and a greater temporal change than the correction coefficient when the tire is normal. In the present invention, the normality or the abnormality of the tire is determined by using the variation amount or the time change amount of the correction coefficient as a characteristic variable indicating the characteristic of the correction coefficient.

Step 1450 is a step for drawing characteristics of the correction coefficient. FIG. 7 shows the detailed procedure of step 1450. In step 1451, the correction coefficient ω
_{n, m} is compared with the maximum correction coefficient _ωmax, and the correction coefficient ωn _{, m}
Is larger than the maximum correction coefficient _ωmax (step 1452). The initial value of the correction coefficient maximum value ω _max is 0, and is cleared for each rotation of the signal rotors 2a to 2d in step 1600 (FIG. 3) described later. In the subsequent step 1453, the correction coefficient ω _{n, m} is compared with the correction coefficient minimum value ω _min, and if the correction coefficient ω _{n, m} is smaller, this is set as the correction coefficient minimum value ω _min (step 1454). The initial value of the minimum correction coefficient ω _min is 0
, And is cleared in the step 1600 where the maximum correction coefficient ω _max is cleared. Thus the correction coefficient for each vehicle speed pulse interrupt process omega _{n, m} is compared with the correction coefficient maximum value omega _max and the correction coefficient minimum value omega _min, and the correction coefficient maximum value omega _max and the correction coefficient minimum value omega _min is updated .

In step 1500 of FIG. 3, step 1
The pulse signal period Δt _n measured at 100 is corrected by equation (4). In the equation, Δt _n ′ is the corrected pulse signal period. Δt _n ′ = Δt _n × ω _{n, m} (4)

FIG. 8 shows a detailed flow of the subsequent step 1600.
Shown in First, in step 1610, the rotation detection unit number is 4
8 is determined, and each time a pulse signal of the rotation detection unit number 48 is input, that is, the signal rotors 2a to 2
Steps 1620 to 1640 are executed for each rotation of d. The step 1620 (5), calculates a difference [Delta] [omega _m of the correction coefficient maximum value omega _max and the correction coefficient minimum value omega _min. After the correction coefficient maximum value ω _max and the correction coefficient minimum value ω _min have been cleared to 0, they have been updated in the vehicle speed pulse interruption process by the pulse signals of the rotation detection unit numbers 1 to 48, so that one rotation of the signal rotors 2a to 2d. near,
Maximum and minimum values. Thus the difference [Delta] [omega _m represents a variation of the correction coefficient of the signal rotor 2 a to 2 d. Δω _m = ω _max -ω _min (5)

Next, at step 1630, step 16
The [Delta] [omega _m calculated at 20 is added to the accumulated value ΣΔω _m. In step 1640, the correction coefficient maximum value _ωmax and the correction coefficient minimum value _ωmin are cleared. Thus, every time the signal rotors 2a to 2d make one rotation, the variation Δω _m of the correction coefficient for the one rotation is calculated, and the integrated value ΣΔω _m is updated. The reason for adding Δω _m is to suppress the influence of road surface vibration and the like by the average action.

FIG. 9 shows the flow of the periodic interrupt processing, which is executed for each periodic interrupt signal of the microcomputer of the ECU 4. First, tires 1a-1d
For each time, the integrated value Δt _s of the corrected pulse signal period and the number N of input pulse signals in the latest periodic interrupt section
_{Based on p} (see FIG. 2), the number of teeth of the signal rotors 2a to 2d (48 in this case) and the speed constant a determined by the wheel radius, the calculation of the wheel speed is executed by the equation (6) (step 2010). V _x = a (N _p / Δt _s ) (6)

In step 2020, it is determined whether a predetermined time has elapsed. The predetermined time is a time defined by a preset number of vehicle speed pulse interruption processes. That is, when the predetermined number of vehicle speed pulse interrupt processes are executed, steps 2030 to 2100 are executed. In the following description, the integrated value of the correction coefficient variation Δω _m ΣΔω
_m is ΣΔω _FR for the right front tire, ΣΔω _FL for the left front tire, ΣΔω _RR for the right rear tire, and ΣΔ for the left rear tire.
ω _RL . In step 2030, the difference Δω _F between the integrated value ΣΔω _FR of the variation Δω _m of the correction coefficient and ΣΔω _FL for the left and right wheels on the front side is calculated by equation (7). Δω _F = | ΣΔω _FR −ΣΔω _FL | ・ ・ ・ ・ (7)

Next, in step 2040, step 2
The difference Δω _F calculated in 030 is compared with a predetermined value. Here, the predetermined value is set in advance based on an experiment or the like to obtain a variation in the correction coefficient between a normal time and an abnormal time, and based on this variation. If the difference [Delta] [omega _F is smaller than the predetermined value the front tire is determined to be normal (Step 20
51), the difference [Delta] [omega _F is determined that a trouble has occurred in the front tires is larger than the predetermined value (Step 2
052). After the judgment, the integrated values ΣΔω _FR and ΣΔω _FL are cleared (step 2060).

In the following steps 2070 to 2100, the presence or absence of abnormality in the rear tire is determined from the integrated values ΣΔω _RR and ΣΔω _RL of the variation Δω _m of the correction coefficient for the rear tire. That is, the difference Δω _R is calculated by the equation (8) (step 2070), and the difference Δω _R is compared with a predetermined value (step 2080) to determine whether the rear tire is normal or abnormal as in the case of the front tire. (Steps 2091 and 2092). Next, the integrated value ΣΔω
_RR and ΣΔω _RL are cleared (step 2100). Δω _R = | ΣΔω _RR −ΣΔω _RL | ・ ・ ・ (8)

In the present embodiment, it is possible to specify not only the presence / absence of a tire abnormality but also the abnormality on the front side or the rear side tire from the correction coefficients for the four wheels.

Although the differences Δω _F and Δω _R are absolute values in the present embodiment, they may be simply values obtained by subtracting the integrated value for the left tire from the integrated value for the right tire.
In this case, it can be determined from the sign whether the tire in which the abnormality has occurred is on the right or left side. Alternatively, the difference between the front wheel and the rear wheel of the integrated value of the variation of the correction coefficient is calculated for each of the left and right wheels, and it can be determined whether the abnormal wheel is the left wheel or the right wheel. Alternatively, the integrated value of the variation of the correction coefficient of each wheel may be independently compared with a predetermined value that defines a normal state and an abnormal state to determine whether there is an abnormality in each wheel. The difference between the current value and the previous value of the integrated value of the variation may be compared with a predetermined value that determines whether the value is normal or abnormal.

Although the deviation between the maximum value and the minimum value of the correction coefficient in one rotation of the signal rotor is used as the variation of the correction coefficient, a statistical value, such as a variance, serving as an index of the variation may be used.

Step 2010 of the periodic interrupt processing
If the fluctuation of the wheel speed calculated in (FIG. 9) is large only on the right side or on the left side of both the front and rear wheels, it may be set so that the road surface is determined to be rough and the presence or absence of tire abnormality is not determined. Thereby, the accuracy of abnormality detection is increased. Further, the determination of the tire abnormality may be limited to a high-speed region in which there is a high possibility that the vehicle is traveling straight or traveling on a road with little road surface roughness.

(Second Embodiment) The configuration of the wheel speed detecting device of this embodiment is basically the same as that shown in FIG.
The software executed mainly by the microcomputer of the ECU 4 is different. FIG. 10 shows the flow of the vehicle speed pulse interruption process. FIG. 11 shows the detailed procedure of step 1400A in FIG. 10, and FIG. 12 shows the detailed procedure of step 1450A in FIG. FIG. 13 shows the flow of the periodic interrupt processing. In the respective drawings, steps denoted by the same reference numerals as those in FIGS. 3, 6, 7, and 8 described in the first embodiment perform substantially the same operation, and therefore, a description will be given focusing on differences from the first embodiment. I do.

Calculation of correction coefficient (FIG. 11, step 144)
In step 1450A after 0), as shown in FIG. 12, first, the temporal change amount Δω _n of the correction coefficient is obtained by equation (9).
Is calculated (step 1455). Δω _n = | ω _{n, m} −ω _{n, m-1} | (9)

In the following step 1456, step 14
Integrated value with time variation [Delta] [omega _n calculated at 55 Shigumaderutaomega
Add to _n . Therefore, the signal rotors 2a to 2d are 1
In each rotation, the calculated temporal variation amount [Delta] [omega _n, the integrated value Shigumaderutaomega _n is updated.

In the periodic interrupt processing shown in FIG.
The wheel speed is calculated in the same procedure as in step 2010 (step 3010). In step 3020, it is determined whether a predetermined time has elapsed. The predetermined time is a time defined by a preset number of vehicle speed pulse interruption processes. That is, when the predetermined number of vehicle speed pulse interruption processes are executed, steps 3030 to 3060 are executed. Steps 3030 to 3060 correspond to each tire 1a.
-1d.

In step 3030, according to equation (10),
The difference Δ (ΣΔω _n ) is calculated and compared with a predetermined value set in advance. The predetermined value is set in advance in an experiment or the like based on a temporal change amount of a correction coefficient at the time of tire abnormality such as air deflation of a tire. Δ (ΣΔω _n ) = | ΣΔω _n -previous value of ΣΔω _n | (10)

In step 3030, the difference Δ (ΣΔω
_{If n} ) is smaller than a predetermined value, it is determined that the tire is normal (step 3041), and if the difference Δ (ΣΔω _n ) is larger than the predetermined value, it is determined that an abnormality has occurred in the tire (step 3042). After determination, updates the previous value of the integrated value Shigumaderutaomega _n to the value of the current integrated value ΣΔω _n (step 3050), and clears the accumulated value ΣΔω _n (Step 3
060).

In this embodiment, since the processing is executed for each of the tires 1a to 1d, not only the presence or absence of the tire abnormality but also the tire in which the abnormality has occurred can be specified.

In the present embodiment, the characteristic variable is the amount of change over time of the correction coefficient of one rotation detector.
The average value may be used for all or a part of the rotation detectors of the change over time 48. In this case, accurate determination can be made even if the rotation detection unit number cannot be specified when the vehicle stops.

Although the difference between the current value and the previous value of the integrated value of the change amount of the correction coefficient with time is compared with a predetermined value, the difference between the wheels may be used as in the first embodiment.

(Third Embodiment) The configuration and the vehicle speed pulse interruption process of the wheel speed detection device of the third embodiment are basically the same as those of the second embodiment, and another example is provided in place of the regular interruption process of the second embodiment. This is a routine interrupt process.
FIG. 14 shows a flow of the periodic interrupt processing of the present embodiment.
In the figure, steps denoted by the same reference numerals as those in FIG. 13 described in the description of the first and second embodiments perform substantially the same operation, and therefore, the description will focus on differences from the second embodiment.

In FIG. 14, in step 3070, it is determined whether or not an initialization operation has been performed. The initialization operation is a switch operation performed by a driver or the like, and is performed when the tire is normal, such as when replacing the tire. Initialization operation is an integrated value Shigumaderutaomega _n stored value, the process proceeds to step 3080 if the set to the integrated value Shigumaderutaomega _n stored in the storage means serving as a backup memory. In the subsequent scheduled interrupt processing, the integrated value ΣΔω
_{The n} stored value is used for determining a tire abnormality.

In step 3090, according to equation (11),
The difference Δ (ΣΔω _n ) is calculated and compared with a predetermined value set in advance. Here, the predetermined value is set in advance based on the amount of change over time of the correction coefficient at the time of occurrence of a tire abnormality such as air deficiency of a tire through experiments or the like. Δ (ΣΔω _n ) = | ΣΔω _n-記憶 stored value of ΣΔω _n | (11)

In step 3090, the difference Δ (ΣΔ
If (ω _n ) is smaller than the predetermined value, it is determined that the tire is normal (step 3101), and if the difference Δ (ΣΔω _n ) is larger than the predetermined value, it is determined that an abnormality has occurred in the wheel (step 3102). After determination, it clears the integrated value ΣΔω _n (step 3110).

In each of the above embodiments, the determination error is suppressed by integrating the characteristic coefficients. However, if the factor of the determination error such as the road surface vibration is small, the integration is not necessary.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a first tire abnormality detection device of the present invention.

FIG. 2 is a first schematic diagram illustrating the operation of the first tire abnormality detection device of the present invention.

FIG. 3 is a first flowchart illustrating the operation of the first tire abnormality detection device of the present invention.

FIG. 4 (a) is a second schematic diagram illustrating the operation of the first tire abnormality detection device of the present invention, and FIG. 4 (b) illustrates the operation of the first tire abnormality detection device of the present invention. It is a 3rd schematic diagram.

FIG. 5A is a third schematic diagram illustrating the operation of the first tire abnormality detection device of the present invention, and FIG. 5B is a diagram illustrating the operation of the first tire abnormality detection device of the present invention. It is a 4th schematic diagram.

FIG. 6 is a second flowchart illustrating the operation of the first tire abnormality detection device of the present invention.

FIG. 7 is a third flowchart illustrating the operation of the first tire abnormality detection device of the present invention.

FIG. 8 is a fourth flowchart illustrating the operation of the first tire abnormality detection device of the present invention.

FIG. 9 is a fifth flowchart illustrating the operation of the first tire abnormality detection device of the present invention.

FIG. 10 is a first flowchart illustrating the operation of the second tire abnormality detection device according to the present invention.

FIG. 11 is a second flowchart illustrating the operation of the second tire abnormality detection device according to the present invention.

FIG. 12 is a third flowchart illustrating the operation of the second tire abnormality detection device according to the present invention.

FIG. 13 is a fourth flowchart illustrating the operation of the second tire abnormality detection device of the present invention.

FIG. 14 is a flowchart illustrating the operation of the third tire abnormality detection device according to the present invention.

[Explanation of symbols]

1a-1d Tires 2a-2d Signal rotors (rotating bodies) 2a-2d Electromagnetic pickups (rotation detecting means) 4 Electronic control devices (deviation amount dependent value calculating means, characteristic variable calculating means, determining means, storage means)

Claims (7)

[Claims] 1. A rotating body that rotates integrally with a wheel and has a plurality of rotation detecting portions formed in a circumferential direction, and a rotating body provided to face the rotating body and detects passage of the rotating body by the rotating detecting portion. Rotation detecting means, a deviation amount dependent value calculating means for calculating a deviation amount dependent value of a detection cycle of a detection signal obtained by the rotation detecting means from a reference value, and a deviation amount dependent value calculating means Characteristic variable calculating means for calculating a characteristic variable indicating the characteristic of the shift amount dependent value calculated in step (a), and determining means for determining a tire state in a binary manner based on the characteristic variable calculated by the characteristic variable calculating means. A tire abnormality detection device characterized by the above-mentioned. 2. The tire abnormality detection device according to claim 1, wherein the characteristic variable is a variation amount of a deviation dependent value in one rotation of the rotating body. 3. The tire abnormality detection device according to claim 1, wherein the characteristic variable is a time-dependent change amount of a deviation amount dependent value. 4. The tire abnormality detection device according to claim 1, wherein the determination unit is configured to compare a difference between the wheels of the characteristic variable with a predetermined value. 5. The tire abnormality detection device according to claim 1, wherein the determination unit is configured to compare a difference between a current value and a previous value of the characteristic variable with a predetermined value. Detection device. 6. The tire abnormality detection device according to claim 1, wherein the determination unit compares a difference between a current value of the characteristic variable and a preset initial value of the characteristic variable with a predetermined value. Tire abnormality detection device set to perform. 7. The tire abnormality detection device according to claim 6, wherein an initial value of the characteristic variable is a value calculated by the characteristic variable calculating means when the tire is normal, and the calculated value is supplied to the determining means. A tire abnormality detection device provided with storage means for storing.