JP4710372B2 - Brake vibration detector - Google Patents

Description

  The present invention relates to a brake vibration detecting device capable of detecting brake vibration generated due to uneven wear of a disc rotor, and a brake vibration suppressing device including the same.

  Normally, in a disc brake, the gap between the disc rotor and the brake pad requires that the power to move the brake pad is required when the amount of movement of the brake pad increases, and that there is a risk of foreign matter entering the gap. The reason is not so large, but when the disc rotor is inclined for some reason, a part of the disc rotor and the brake pad come into contact with each other during non-braking (dragging), and uneven wear occurs when traveling for a long time in that state. When such uneven wear occurs, when the disc rotor is sandwiched between the brake pads during the braking operation, a sufficient frictional force cannot be obtained only at the specific part where the uneven wear occurs, so that the braking torque varies. Then, the brake vibration is generated by the resonance phenomenon caused by the braking torque fluctuation.

In order to detect such brake vibration, conventionally, for example, in Patent Document 1, the fact that the brake hydraulic pressure fluctuates due to the brake vibration is used, and the brake vibration is detected by detecting the fluctuation of the brake hydraulic pressure with a hydraulic sensor. An apparatus has been proposed.
JP 2000-85554 A

  However, when the brake vibration is detected by detecting the brake oil pressure as shown in Patent Document 1, the fluctuation of the brake oil pressure caused by the brake vibration is very small with respect to the brake oil pressure generated during the actual brake operation. Is. For this reason, there is a problem that a highly accurate and expensive hydraulic sensor is required which can accurately detect such a minute change in brake hydraulic pressure and can withstand the original brake hydraulic pressure.

  In addition, although the fluctuation of the brake hydraulic pressure depends to some extent on the amount of uneven wear of the disk rotor, the thickness of the disk rotor is not amplified even if the steering system resonates due to the resonance phenomenon of the brake vibration, that is, the braking torque fluctuation. The displacement width of the brake pad is not amplified. For this reason, it does not necessarily depend on the magnitude of vibration generated as a result of the resonance phenomenon, and there is a problem that it is difficult to reliably detect the occurrence of brake vibration.

  The present invention has been made in view of the above points, and it is an object of the present invention to provide a brake vibration detection device that detects brake vibration by another method instead of detecting brake hydraulic pressure.

In order to achieve the above object, according to the first aspect of the present invention, there are a plurality of teeth comprising a combination of a convex portion and a concave portion and rotation of each of a plurality of wheels (FL, FR, RL, RR). Convex portions on the teeth of the sensor rotor, which are output from the wheel speed sensors (91 to 94) arranged to face the teeth of the sensor rotor with respect to the sensor rotor (95 to 98) rotated along with On the basis of the detection signal corresponding to the positional relationship between the motor and the recess, the electronic control device (30) detects the brake vibration, and the electronic control device includes a wheel speed calculation means (110) and a wheel speed difference calculation means (120). And a filter processing means (130), a determination means (150), and a brake vibration detection means (180).

Specifically, the wheel speed calculation means calculates the wheel speed (V **) of each of the plurality of wheels based on the detection signal of the wheel speed sensor. The wheel speed difference calculation means calculates the wheel speed difference (Vdif), which is the difference between the wheel speeds of two of the plurality of wheels, using the wheel speeds of the plurality of wheels obtained by the wheel speed detection means. . When the wheel speed difference obtained by the wheel speed difference calculating means is filtered by the high-pass filter using the filter processing means, and the detection signal of the wheel speed sensor is obtained by the judging means (150). The vehicle speed is determined, and it is determined whether or not the vehicle speed is within a predetermined vehicle speed range. Further, in the brake vibration detection means, the vehicle enters a detection result of the brake detecting means for detecting whether or not during braking (10), when the detection result of the braking detecting means was during braking In addition, when the vehicle speed is determined to be within the predetermined vehicle speed range by the determination unit, the occurrence of the brake vibration is detected when the wheel speed difference after the filter processing by the filter processing unit is equal to or greater than the brake vibration detection reference. . The predetermined vehicle speed range is a vehicle speed at which a resonance phenomenon occurs when the steering system resonance frequency of the vehicle coincides with the rotation primary or secondary rotation of the wheels.

According to such a configuration, when the detection result of the braking detection means is being braked, and the determination means determines that the vehicle speed is within the predetermined vehicle speed range, the wheel speed difference is equal to the predetermined brake. The brake vibration can be detected based on whether or not the vibration detection standard is exceeded. That is, it becomes possible to detect the brake vibration based on the detection signal of the wheel speed sensor.

Therefore, it is only necessary to use a sensor with a simple configuration called a wheel speed sensor, and it is possible to detect brake vibration without using a high-precision and expensive sensor as in the case of obtaining brake vibration based on fluctuations in conventional brake hydraulic pressure. It becomes possible to do. And since such a wheel speed sensor is generally mounted on a vehicle where ABS control or the like is currently performed, it is possible to detect a brake vibration without installing another component.
Further, by performing filter processing using a high-pass filter, it is possible to remove, for example, an offset amount due to turning, that is, low-frequency noise generated by turning.
Furthermore, the occurrence of brake vibration is detected based on a wheel speed difference when it is determined that the vehicle speed is within a predetermined vehicle speed range, for example, a range of about 100 km / h ± 10 km / h or about 50 km / h ± 10 km / h. Therefore, it is possible to detect the brake vibration based on the wheel speed difference having a large gain. Thereby, it becomes possible to detect the brake vibration more accurately.

  The invention according to claim 2 is characterized in that the wheel speed difference calculating means obtains the wheel speed difference between the left and right front wheels and the wheel speed difference between the left and right rear wheels among the plurality of wheels as the wheel speed difference. Yes.

  In this way, if the combination for obtaining the wheel speed difference is a combination of the left and right front wheels and the left and right rear wheels, noise due to the influence of the drive torque that can be generated on the drive wheels can be eliminated, and the tires on the front wheels and the rear wheels can be removed. Even when the size is different, it is possible to cope with it. For this reason, such a combination is preferable.

According to a third aspect of the present invention, the electronic control device is provided with a square sum integrating means (160) for integrating the square sum of the wheel speed difference obtained by the wheel speed difference calculating means by a predetermined number of times. The brake vibration detecting means detects the occurrence of brake vibration when the integrated value of the square sum integrating means (160) is equal to or greater than a predetermined threshold value corresponding to a brake vibration detection criterion. It is said.

  Thus, the brake vibration can also be detected based on whether or not the value obtained by summing the square sum of the wheel speed differences exceeds the threshold value. Thereby, a noise component can be smoothed and generation | occurrence | production of a brake vibration can be detected more correctly.

In the invention according to claim 4 , the electronic control device obtains a parameter value that causes a variation in the gain of the wheel speed difference obtained by the wheel speed difference calculation means, and based on the parameter value, the wheel speed is calculated. A correction means for correcting the difference gain is provided.

  In this way, if a parameter that causes fluctuations in the wheel speed difference is obtained and the gain of the wheel speed difference is corrected based on the value of the parameter, the wheel speed difference can be reduced even when the gain of the wheel speed difference is reduced. The brake vibration can be detected with a gain that is the same as when the gain is large.

  Examples of such parameters include vehicle speed, braking torque, and disk rotor temperature.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
A brake vibration detection apparatus to which an embodiment of the present invention is applied will be described. FIG. 1 shows a block configuration of a brake vibration detection device 1 of the present embodiment. Hereinafter, with reference to FIG. 1, the brake vibration detection apparatus 1 of this embodiment is demonstrated.

  As shown in FIG. 1, the brake vibration detection device 1 includes a stop switch 10, wheel speed sensors 21 to 24, an ECU 30 for detecting brake vibration, and an alarm device 40.

  The stop switch 10 corresponds to braking detection means, and detects whether or not a brake pedal as a brake operation member (not shown) has been depressed, and detects whether or not the vehicle is braking. Used. When the brake pedal is depressed by the driver, the stop switch 10 is turned on, and a detection signal indicating it is output from the stop switch 10.

  The wheel speed sensors 21 to 24 are equipped with gear-type sensor rotors 25 to 28 having a large number of (for example, 48) tooth portions arranged at substantially equal intervals, which are provided in the respective wheels FL, FR, RL, and RR. It arrange | positions in the position facing the tooth | gear part. The wheel speed sensors 21 to 24 are constituted by, for example, electromagnetic pickup type, and the direction of the magnetic field generated by the magnets provided in the wheel speed sensors 21 to 24 by the unevenness of the tooth parts provided in the sensor rotors 25 to 28. Therefore, a detection signal that is a pulse signal (sine wave) is output based on the change in the output of the magnetoresistive element. Based on this detection signal, the rotational state of the sensor rotors 25 to 28, that is, the rotational state of the wheels FL, FR, RL, and RR is detected.

  The brake vibration detection ECU 30 is constituted by a well-known microcomputer (electronic control device) having a CPU, ROM, RAM, I / O, and the like, and various data stored in the RAM according to a program stored in the ROM. Various operations and the like are executed using the. When the brake vibration detecting ECU 30 detects the brake vibration, the ECU 30 outputs an electric signal indicating that to the alarm device 40.

  The alarm device 40 is composed of, for example, an in-vehicle buzzer, an alarm lamp, or a display device, and issues an alarm to the driver that brake vibration has occurred. The alarm device 40 receives an electric signal from the ECU 30 for detecting brake vibration and informs the driver that brake vibration is occurring.

  Next, a method of brake vibration detection by the brake vibration detection device 1 configured as described above will be described.

  First, the brake vibration detection principle by the brake vibration detection device 1 of the present embodiment will be described.

  As described above, when uneven wear occurs in the disc rotor, when the disc rotor is sandwiched between the brake pads during the braking operation, a sufficient frictional force cannot be obtained only at the specific portion where the uneven wear occurs, and the braking torque varies. . When this braking torque fluctuation occurs, the sidewall between the tire ground contact surface and the axle acts as a spring, so that the vibration torque fluctuation appears as a wheel rotation fluctuation in the wheel speed due to the expansion and contraction of the spring.

  For this reason, a difference occurs in the wheel speed between a wheel in which uneven wear has not occurred in the disk rotor and a wheel in which uneven wear has occurred. In other words, during braking, the wheel speed of the disc rotor is unevenly worn, and the wheel speed of the disc rotor is higher than when a specific portion of the disc rotor is sandwiched between the brake pads and other locations. Get faster. However, with respect to a wheel in which uneven wear has not occurred in the disk rotor, the disk speed does not increase because the disk rotor in which uneven wear has not occurred is sandwiched between brake pads. For this reason, a difference in wheel speed occurs between a wheel in which uneven wear has not occurred in the disk rotor and a wheel in which uneven wear has occurred.

  Therefore, by comparing the wheel speeds of the respective wheels FL, FR, RL, and RR and detecting the difference between them, it is possible to detect whether or not there is a wheel in which uneven wear occurs in the disk rotor. Become. At this time, the combination of the wheels for comparing the wheel speeds may be any combination. However, the drive wheels may be affected by noise due to the drive torque, and the front wheels FL, FR and the rear wheels RL, RR. Since the tire sizes are different from each other, the combination of the front wheels FL and FR and the rear wheels RL and RR is preferable.

  FIGS. 2 and 3 are views showing a state when, for example, the difference in wheel speed between the front wheels is examined, and FIG. 2 is a diagram in the case of a normal rotor in which uneven wear does not occur in the disk rotor. 3 is a diagram in the case of a partial wear rotor in which partial wear has occurred in the disk rotor. 2 and 3, the vehicle speed and the brake pedal operation (stop switch 10 on / off state) are also shown in order to clarify the relationship between the wheel speed difference and the brake operation.

  First, referring to FIG. 2, it can be seen that the difference in wheel speed between the left and right wheels is small when there is no uneven wear on the disc rotor in both the left and right wheels. In contrast, when FIG. 3 shows that uneven wear has occurred in any of the disc rotors of the left and right wheels, the left and right wheels start from when the brake pedal is depressed (when the stop switch 10 is turned on). It can be seen that there is a large difference in wheel speed.

  Thus, the difference between the wheel speeds of the left and right wheels during braking is obtained, and when the difference between the wheel speeds is increased, the brake vibration can be detected as having occurred.

  In addition, the sampling period of the wheel speed of each wheel FL, FR, RL, RR is set to about 6 ms, for example, and is sufficiently shorter than the period in which each wheel FL, FR, RL, RR makes one rotation. For this reason, fluctuations in wheel speed due to uneven wear of the disk rotor are sufficiently reflected in the difference in wheel speed between the left and right wheels.

  Next, a specific brake vibration detection method based on the above-described principle of brake vibration detection will be described. FIG. 4 is a flowchart of a brake vibration detection process executed by the brake vibration detection ECU 30 in the brake vibration detection device 1 of the present embodiment. The processing shown in this figure is executed for each wheel FL, FR, RL, RR in accordance with a program stored in the ROM of the ECU 30 for detecting brake vibration, and has a predetermined calculation cycle (wheel speed sampling). (Period).

  First, in step 100, detection signals of the wheel speed sensors 21 to 24 are input. Since the input of the detection signals of the wheel speed sensors 21 to 24 here is executed at every predetermined calculation cycle, the unit time sampling is generally performed as the detection of the wheel speed. That is, the detection signals of the wheel speed sensors 21 to 24 per unit time are input as they are.

  Next, at step 110, the wheel speed V ** of each wheel FL, FR, RL, RR is calculated. A portion of the ECU 30 that executes this process corresponds to a wheel speed calculation unit. Note that “**” in the wheel speed V ** corresponds to each wheel FL, FR, RL, RR and is attached as a subscript.

  The wheel speed V ** is detected from the detection signal input in step 100 to determine how many teeth of the sensor rotors 25 to 28 are detected per unit time, which is determined by the wheels FL, FR, RL, After being converted into the travel distance obtained from the circumference of RR, for example, it is calculated by being converted into speed.

  Thereafter, the process proceeds to step 120, where the wheel speed difference Vdif between the left and right wheels is obtained. A portion of the ECU 30 that executes this process corresponds to a wheel speed difference calculation unit.

  Specifically, a wheel speed difference (FL−FR) between the left front wheel FL and the right front wheel FR and a wheel speed difference (RL−RR) between the left rear wheel RL and the right rear wheel RR are obtained.

  In step 130, the wheel speed difference Vdif is filtered by a high-pass filter to obtain a wheel speed difference Vh. A portion of the ECU 30 that executes this process corresponds to a filter processing unit.

  This filtering process is to prevent the square sum integrated value from increasing due to the offset when removing the offset due to turning, for example, and obtaining the magnitude of vibration by square sum integration in step 160. A high-pass filter is used so that low-frequency noise generated by turning can be removed.

  Subsequently, in step 140, it is determined whether or not the wheel speed difference Vh determined this time is during braking. Whether or not braking is being performed is determined based on whether or not a detection signal indicating that the brake has been turned on is output from the stop switch 10, and a detection signal that indicates that the brake has been turned on is output from the stop switch 10. If so, it is treated as being braked.

  If a negative determination is made in this step, the processing is completed as it is, assuming that the wheel speed difference due to uneven wear of the disk rotor does not occur. If an affirmative determination is made, the routine proceeds to step 150, where it is determined whether or not the currently obtained wheel speed difference Vh is within a predetermined vehicle speed range. A portion of the ECU 30 that executes this process corresponds to a determination unit.

  The predetermined vehicle speed range corresponds to the vehicle speed at which the resonance frequency of the steering system coincides with the rotation primary or secondary rotation of the wheel and the resonance phenomenon occurs, and varies depending on the tire diameter and the steering system for each vehicle. A range of about / h ± 10 km / h or about 50 km / h ± 10 km / h is shown. At the vehicle speed at which the resonance phenomenon occurs, the influence of the wheel speed due to the brake vibration appears more strongly than at other vehicle speeds. For this reason, although it is possible to detect the brake vibration using the wheel speed difference Vh when it is outside the predetermined vehicle speed range, the brake vibration is detected using the wheel speed difference Vh when it is within the predetermined vehicle speed range. Thus, more accurate brake vibration detection can be performed.

  As the vehicle speed at this time, the wheel speed V ** of each wheel FL, FR, RL, RR may be used as it is, but a general method for obtaining the vehicle speed from the wheel speed V ** (the wheel speed V ** of The method using the largest of them, the method using three average values excluding the slowest one), etc., or when the vehicle speed is determined by another ECU mounted on the vehicle Information may be obtained from the ECU. Of course, if the vehicle is equipped with a vehicle speed sensor, the vehicle speed may be obtained by inputting a detection signal from the vehicle speed sensor.

  Note that the predetermined vehicle speed range has been described by taking, for example, a range of about 100 km / h ± 10 km / h or about 50 km / h ± 10 km / h as an example. This is because the primary resonance frequency (the primary rotation frequency of the wheel rotation) is Since vehicle speed of about 100 km / h and secondary resonance frequency (wheel rotation secondary resonance frequency) is about 50 km / h, these are given as examples. But the same is true. However, in this case, the resonating vehicle speed becomes a considerably low value, and the gain of the wheel speed difference becomes small. Therefore, the predetermined vehicle speed range is set based on the vehicle speed corresponding to the primary resonance frequency or the secondary resonance frequency. It is preferable to set.

  If a negative determination is made in step 150, the brake vibration is not detected at the wheel speed difference Vh obtained this time in order to perform more accurate brake vibration detection, and the process is completed as it is. On the other hand, if an affirmative determination is made, the routine proceeds to step 160 in order to detect the brake vibration as it is.

  In step 160, square sum integration processing is executed. The sum of squares sums values obtained by squaring the wheel speed difference Vh. A portion of the ECU 30 that executes this process corresponds to a square sum integrating means. Although it is not always necessary to perform such sum of square sums, vibration energy of a waveform that changes positively and negatively can be easily evaluated by performing sum of squares.

Specifically, a value Vh ² obtained by squaring the wheel speed difference Vh obtained this time is added to the previous accumulated value S, and the value (S + Vh ² ) is stored as a new accumulated value. For example, the cumulative number is stored in the brake ECU 70 by incrementing the cumulative number counter by one.

  When this process is finished, the routine proceeds to step 170, where it is determined whether or not the integration number has been completed, that is, whether or not the integration number has reached a predetermined number. The predetermined number of times referred to here is a value set in advance as the number of integrations. If the number of integrations stored in step 160 reaches this number, an affirmative determination is made in this process.

  When a negative determination is made here, each of the above processes is repeated until a preset integration number is reached. If an affirmative determination is made, the routine proceeds to step 180, where it is determined whether or not the sum of square sums obtained at step 160 is greater than or equal to a predetermined threshold value preset as a brake vibration detection criterion. . The predetermined threshold here is adjusted according to the degree of warning you want to give, but by setting it to a level that is difficult to notice from the experience, you can contribute to avoiding danger due to abnormal vibration during high speed driving Is possible. In addition, the part which performs this process among ECU30 corresponds to a brake vibration detection means.

  If a negative determination is made in this step, it is determined that no brake vibration has occurred, and the process proceeds to step 190, where each value stored in the current process, for example, the sum of square sums or the number of integrations is cleared. This completes the process. If an affirmative determination is made in this step, it is determined that brake vibration has occurred, the process proceeds to step 200, and an alarm process is executed. This alarm processing is to output a command signal that gives an alarm to the alarm device 40 that the brake vibration has occurred. Upon receiving this command signal, the alarm device 40 generates a brake vibration to the driver. I can tell you what you are doing.

  As described above, according to the brake vibration detection device 1 of the present embodiment, the brake vibration can be detected based on, for example, whether or not the wheel speed difference between the left and right wheels is equal to or greater than a predetermined threshold value. That is, it becomes possible to detect the brake vibration based on the detection signals of the wheel speed sensors 21 to 24.

  Therefore, it is sufficient to use a sensor having a simple configuration of the wheel speed sensors 21 to 24, and without using a high-precision and expensive sensor as in the case of obtaining brake vibration based on fluctuations in the conventional brake hydraulic pressure. Vibration can be detected. Such wheel speed sensors 21 to 24 are generally mounted on a vehicle where ABS control or the like is currently performed, so that it is possible to detect the brake vibration without newly mounting another component. Can do.

(Second Embodiment)
A second embodiment of the present invention will be described. The brake vibration detection device 1 of the present embodiment has the same configuration as that of the first embodiment, and differs only in the processing executed by the brake vibration detection ECU 30 in the brake vibration detection device 1. Only will be described.

  In the above embodiment, the wheel speed difference Vh between the left and right wheels used in step 130 is used as it is. However, since the gain of the wheel speed difference Vh varies depending on the vehicle situation, the correction for the variation is corrected. You may make it do.

  For example, when the vehicle speed falls within the predetermined vehicle speed range as in step 150 described above, the gain of the wheel speed difference Vh becomes the largest. Therefore, the wheel speed difference Vh obtained at the vehicle speed within the range is detected as the brake vibration. However, the processing at this step can be changed to correction processing.

  That is, the ratio or reduction of how much the gain at a vehicle speed outside the predetermined vehicle speed range decreases with respect to the gain of the wheel speed difference Vh within the predetermined vehicle speed range (particularly, the peak value of the gain of the wheel speed difference Vh). The quantity itself is stored in advance by associating it with the vehicle speed by finding it through experiments or learning. Then, from the vehicle speed when the wheel speed difference Vh is obtained, the reduction rate or reduction amount corresponding to the vehicle speed is read, and the obtained wheel speed difference Vh is multiplied by the reciprocal of the reduction rate or the reduction amount is added. Thus, the gain of the wheel speed difference Vh is corrected.

  In this way, even if the gain of the wheel speed difference Vh fluctuates according to the vehicle speed, the wheel speed difference Vh can be corrected in anticipation of the fluctuation according to the vehicle speed, and obtained at various vehicle speeds. It becomes possible to detect the brake vibration using the wheel speed difference Vh.

  When such correction is performed, for example, a correction processing step is provided instead of the above-described step 150, and correction corresponding to the vehicle speed can be performed at this step. In this case, a portion of the ECU 30 that executes this process corresponds to a correction unit.

(Other embodiments)
In the above embodiment, an example of using an electromagnetic pickup type as the wheel speed sensors 21 to 24 is given. However, if the detection signal fluctuates with the movement of the tooth portions of the sensor rotors 25 to 28, other It may be of a known type. Moreover, although the example which uses a gear-type thing as the sensor rotors 25-28 was given in the said embodiment, a magnetic material was embedded in the rotary body of a nonmagnetic material, and a gear type was exposed by exposing the magnetic material at equal intervals. A rotor switch having the same configuration as that of the sensor rotor is also included in the sensor rotor of the present invention. In this case, the plurality of magnetic materials exposed at equal intervals in the rotor switch correspond to the convex portions of the teeth, and the portions where the magnetic materials are not exposed, that is, the portions located between the plurality of exposed magnetic materials are the teeth. It corresponds to a recess and plays the same role as the gear-type sensor rotors 25 to 28.

  In the second embodiment, the case where the wheel speed difference Vh is corrected according to the gain of the wheel speed difference Vh that fluctuates according to the vehicle speed is described as an example. It is possible to correct the wheel speed difference Vh according to the gain of the wheel speed difference Vh that fluctuates according to the change of the parameter.

  Specifically, when the braking torque changes, the wheel speed difference Vh varies according to the change. Also in this case, the gain of the wheel speed difference Vh is the largest when the braking torque is within the predetermined range, and the gain of the wheel speed difference Vh is reduced when the braking torque is outside the predetermined range as compared with the case where it is within the predetermined range. .

  Therefore, also in this case, with respect to the gain of the wheel speed difference Vh when the braking torque is within the predetermined range (particularly, the peak value of the gain of the wheel speed difference Vh), the braking torque is outside the predetermined range. The ratio of how much the gain is reduced or the amount of reduction itself is obtained in advance by experiment or learning and stored in association with the braking torque. Then, the reduction rate or reduction amount corresponding to the braking torque is read from the braking torque when the wheel speed difference Vh is obtained, and the obtained wheel speed difference Vh is multiplied by the reciprocal of the reduction rate or the reduction amount. By adding, the gain of the wheel speed difference Vh is corrected.

  However, when it is difficult to obtain the raw value of the braking torque, the wheel cylinder pressure and the deceleration G that can be used to estimate the braking torque are used, and the brake hydraulic pressure and the deceleration G are converted into the braking torque, or The wheel speed difference Vh can be corrected using these directly as parameters.

  Further, even if the disk rotor temperature changes, the wheel speed difference Vh varies according to the change. In this case, the gain of the wheel speed difference Vh becomes the largest when the disc rotor reaches a predetermined temperature or higher, and the gain of the wheel speed difference Vh decreases when the temperature is lower than the predetermined temperature as compared with the case where the temperature becomes the predetermined temperature or higher.

  Therefore, also in this case, the temperature of the disc rotor is lower than the predetermined temperature with respect to the gain of the wheel speed difference Vh (particularly, the peak value of the gain of the wheel speed difference Vh) when the disc rotor reaches a predetermined temperature or higher. The ratio of how much the gain in the case decreases, or the amount of decrease itself is obtained in advance by experiment or learning, and is stored in association with the temperature of the disk rotor. Then, from the temperature of the disk rotor when the wheel speed difference Vh is obtained, the reduction rate or reduction amount corresponding to the temperature is read, and the obtained wheel speed difference Vh is multiplied by the reciprocal of the reduction rate or the reduction amount. Is added to correct the gain of the wheel speed difference Vh.

  However, if it is difficult to determine the raw value of the disk rotor temperature, the number of times of braking and the number of times of braking and the amount of deceleration (integrated value of deceleration) that can estimate the temperature of the disk rotor are used. The wheel speed difference Vh can be corrected by converting the amount of deceleration into the temperature of the disk rotor or using these directly as parameters.

  Moreover, although the process of the said step 140 or step 150 is performed after calculating | requiring the wheel speed difference Vh, you may make it perform before calculating | requiring the wheel speed difference Vh.

  Furthermore, in the above embodiment, the value obtained by summing the square sum of the wheel speed difference Vh is compared with a predetermined threshold value. However, this is to smooth the noise component as described above, and it may be determined whether or not the wheel speed difference Vh itself is equal to or greater than the brake vibration detection standard.

  The steps shown in each figure correspond to means for executing various processes.

It is a figure which shows the block configuration of the brake vibration detection apparatus in 1st Embodiment of this invention. It is the figure which showed the mode when the difference in the wheel speed of a right-and-left wheel was investigated in the case of the normal rotor which has not generate | occur | produced uneven wear in a disk rotor. It is the figure which showed the mode when the difference in the wheel speed of a right-and-left wheel was investigated in the case of the uneven wear rotor in which the uneven wear has generate | occur | produced in the disk rotor. It is a flowchart of the brake vibration detection process which ECU for brake vibration detection performs in the brake vibration detection apparatus shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Brake vibration detection apparatus, 10 ... Stop switch, 21-24 ... Wheel speed sensor, 25-28 ... Sensor rotor, 30 ... ECU for brake vibration detection, 40 ... Alarm device.

Claims (4)

For a sensor rotor (25-28) having a plurality of teeth comprising a combination of a convex part and a concave part and rotated in accordance with the rotation of each of a plurality of wheels (FL, FR, RL, RR) The detection signal according to the positional relationship between the convex portion and the concave portion in the tooth of the sensor rotor, which is output from a wheel speed sensor (21 to 24) disposed so as to face the tooth of the sensor rotor. the sampled short sampling every period than the time period in which the wheel rotates once, on the basis of the sampled detection signal, a brake vibration detection that put the vehicle comprising a electronic control unit for sensing the brake vibrations (30) A device,
The electronic control device
Wheel speed calculation means (110) for calculating the wheel speed (V **) of each of the plurality of wheels based on the detection signal of the wheel speed sensor;
A wheel speed difference calculation that calculates a wheel speed difference (Vdif) that is a difference between the wheel speeds of two of the plurality of wheels, using the wheel speeds of the plurality of wheels obtained by the wheel speed detecting means. Means (120);
A filter processing means (130) for filtering the wheel speed difference obtained by the wheel speed difference calculating means with a high-pass filter;
Determining means (150) for determining the vehicle speed when the detection signal of the wheel speed sensor is obtained, and determining whether the vehicle speed is within a predetermined vehicle speed range;
The detection result of the braking detection means (10) for detecting whether or not the vehicle is being braked is input, and the detection result of the braking detection means is being braked , and the determination means Brake vibration detection means for detecting the occurrence of brake vibration when the vehicle speed is determined to be within the predetermined vehicle speed range and the wheel speed difference after the filter processing by the filter processing means is greater than or equal to a brake vibration detection reference. (180)
The brake vibration detection device according to claim 1, wherein the predetermined vehicle speed range is a vehicle speed at which a resonance phenomenon occurs when a steering system resonance frequency of the vehicle coincides with a primary rotation or secondary rotation of the wheel .   2. The wheel speed difference calculation means obtains a wheel speed difference between left and right front wheels and a wheel speed difference between left and right rear wheels among the plurality of wheels as the wheel speed difference. Brake vibration detection device. The electronic control unit has square sum integration means (160) for integrating the sum of squares of the wheel speed difference obtained by the wheel speed difference calculation means by a predetermined number of integration times,
The brake vibration detecting means detects the occurrence of brake vibration when the value integrated by the square sum integrating means (160) is equal to or greater than a predetermined threshold value corresponding to the brake vibration detection criterion. The brake vibration detection device according to claim 1 or 2 . The electronic control unit obtains a value of a parameter that causes a variation in the gain of the wheel speed difference obtained by the wheel speed difference calculating means, and corrects the gain of the wheel speed difference based on the value of the parameter. The brake vibration detecting device according to any one of claims 1 to 3 , further comprising correction means for performing correction.

Images