JP4450215B2 - Brake vibration detector - Google Patents

Description

  The present invention relates to a brake vibration detection device capable of detecting brake vibration generated by uneven wear of a disk rotor.

  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

  As described above, the brake vibration is detected by detecting a physical quantity that varies in relation to the brake vibration, such as brake hydraulic pressure, or by detecting the brake vibration itself with a vibration sensor or the like. The brake vibration is detected by determining whether the gain of the physical quantity related to the brake vibration or the gain of the brake vibration exceeds a predetermined threshold value, for example.

  However, the gain of the physical quantity related to the brake vibration and the gain of the brake vibration vary depending on the situation of the vehicle and are not always constant. Therefore, the gain of the physical quantity related to the detected brake vibration and the gain of the brake vibration If it is used as it is, there is a problem that the brake vibration may not be detected accurately.

  An object of this invention is to provide the brake vibration detection apparatus which can detect a brake vibration more correctly in view of the said point.

In order to achieve the above object, according to the first aspect of the present invention, the brake detecting means (10) for detecting whether or not the vehicle is being braked detects that the vehicle is being braked. a signal generating means for generating a detection signal including a vibration component (5), a filtering means for passing said detection signal the signal generating means is generated in the band-pass filter (110), after the treatment with the filtering means Gain calculating means (130) for obtaining the average value (S) of the vibration gain obtained by averaging the gains of the detection signals, and obtaining the value of the parameter that causes the fluctuation value of the average value of the vibration gain obtained by the gain calculating means. , based on the value of the parameter, and correcting means for correcting for an average value of the vibration gain (140), the average value of the vibration gain corrected by the correction means Tokoro It is characterized by having a brake vibration detecting means for detecting the occurrence of brake vibration (150) by whether it is a brake vibration determination threshold or more.

  For example, the signal generating means may be a vibration sensor attached to a steering system or the like in a vehicle.

  Thus, if the value of the parameter that causes the fluctuation of the vibration gain is obtained, the vibration gain is corrected based on the value of the parameter, and the brake vibration is detected based on the corrected vibration gain. It is possible to accurately detect the brake vibration.

Specifically, as described in claim 2 , the vehicle speed is cited as a parameter that causes fluctuations in the vibration gain, and the correction means corrects the vibration gain based on the vehicle speed obtained by the vehicle speed detection means. .

For example, as shown in claim 3 , when the vibration gain reaches a peak when the vehicle speed reaches a predetermined vehicle speed, it is based on the relationship between the decrease rate or the decrease amount of the vibration gain at an arbitrary vehicle speed with respect to the vibration gain peak. The relationship of the correction values obtained at any vehicle speed is stored in the storage means. Then, the correction means obtains the vehicle speed when the vibration gain is obtained by the gain calculation means from the vehicle speed obtained by the vehicle speed detection means, and sets the correction value at the vehicle speed to the correction value at an arbitrary vehicle speed. It can obtain | require from a relationship and can correct | amend using the calculated | required correction value.

In this case, as described in claim 4 , in the correction by the correcting means, a predetermined speed range including a predetermined vehicle speed at which the vibration gain reaches a peak is set as a correction application range, and the vibration gain is obtained by the gain calculating means. The vehicle speed is preferably set only when the vehicle speed is within the correction application range.

  In this way, it is possible to prevent correction even when the vehicle speed is such that the vibration gain does not change much according to the degree of uneven wear of the disc rotor, and more accurate brake vibration detection can be performed. Become.

Further, as shown in claim 5, the braking torque mentioned as parameters cause a change of the oscillation gain, the correction means, the correction of the vibration gain is performed based on the braking torque obtained by the braking torque detecting means .

For example, as shown in claim 6 , when the vibration gain reaches a peak when the braking torque reaches a predetermined braking torque, the rate or amount of decrease in the vibration gain at an arbitrary braking torque with respect to the peak of the vibration gain is obtained. The relationship of correction values at the time of an arbitrary braking torque obtained based on the relationship is stored in the storage means. Then, the correction means obtains the braking torque when the vibration gain is obtained by the gain calculation means from the braking torque obtained by the braking torque detection means, and sets the correction value at the time of the braking torque to an arbitrary braking torque. It can be obtained from the relationship of the correction values at the time, and correction can be performed using the obtained correction values.

In this case, as described in claim 7 , the correction by the correction means is performed by setting a predetermined braking torque range including a predetermined braking torque at which the vibration gain has a peak as a correction application range, and the gain calculating means by the vibration gain. It is preferable that the braking torque is calculated only when the braking torque is within the correction application range.

  In this way, it is possible to prevent correction even when the braking torque is such that the vibration gain does not change much according to the degree of uneven wear of the disk rotor, and more accurate brake vibration detection can be performed. It becomes.

In this way, when the braking torque is a parameter, as shown in claim 8 , the braking torque detection means not only directly obtains the braking torque but also detects a deceleration or a wheel cylinder pressure that estimates the braking torque. You can also In this case, the braking torque may be estimated from the deceleration or the wheel cylinder pressure, or the deceleration or the wheel cylinder pressure itself may be used as a parameter corresponding to the braking torque.

Further, as described in claim 9 , the temperature of the disk rotor is also mentioned as a parameter that causes the fluctuation of the vibration gain, and the correction means corrects the vibration gain based on the temperature of the disk rotor obtained by the temperature detection means. Is done.

For example, as shown in claim 10 , when the vibration gain reaches a peak when the disk rotor is at a predetermined temperature or higher, the rate or amount of decrease in the vibration gain at an arbitrary temperature with respect to the peak of the vibration gain. The relationship of correction values at an arbitrary temperature obtained based on the relationship is stored in the storage means. Then, the correction means obtains the temperature of the disk rotor when the vibration gain is obtained by the gain calculation means from the temperature of the disk rotor obtained by the temperature detection means, and sets the correction value at the temperature to an arbitrary temperature. Correction can be performed using the correction value obtained from the relationship of the correction value at this time.

In this case, as described in claim 11 , the correction by the correction means is performed by setting a predetermined temperature range including a predetermined temperature at which the vibration gain reaches a peak as a correction application range, and obtaining the vibration gain by the gain calculation means. It is preferable that this is performed only when the temperature of the disc rotor when it is within the correction application range.

  In this way, it is possible to prevent correction even when the temperature is such that the vibration gain does not change much according to the degree of uneven wear of the disk rotor, and it is possible to perform more accurate brake vibration detection. Become.

When the temperature of the disk rotor is used as a parameter in this way, as shown in claim 12 , the temperature detection means can also detect the braking frequency or the deceleration amount that analogizes the temperature of the disk rotor. In this case, the temperature of the disk rotor may be estimated from the braking frequency or the deceleration amount, or the braking frequency or the deceleration amount itself may be used as a parameter corresponding to the temperature of the disk rotor.

  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 vibration sensor 5, a stop switch 10, wheel speed sensors 21 to 24, an ECU 30 for detecting brake vibration, and an alarm device 40.

  The vibration sensor 5 is attached to the vehicle body, and detects the vibration generated by transmitting the brake vibration itself or the brake vibration. This vibration sensor 5 corresponds to a signal generating means for generating a detection signal including a brake vibration component. For example, since the brake vibration is mainly transmitted to the steering system of the vehicle, the brake vibration is preferably installed in the steering system. However, the brake vibration may be installed in another part to which the brake vibration is transmitted, for example, the body. In addition, the brake caliper or the brake pad may be installed so as to detect the brake vibration itself. The vibration sensor 5 is composed of, for example, a strain gauge type sensor, and the strain gauge is displaced in accordance with the vibration, and the current value flowing through the strain gauge fluctuates. Therefore, the current value is detected based on the brake vibration. As output.

  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 configured by a known microcomputer having a CPU, ROM, RAM, I / O, and the like, and uses various data stored in the RAM in accordance with a program stored in a storage means such as a ROM. Various operations are performed. 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.

  FIG. 2 shows an overall flowchart of the brake vibration detection process executed by the brake vibration detection ECU 30 provided in the brake vibration detection device 1 of the present embodiment. The process shown in this figure is executed every predetermined calculation cycle, and is executed, for example, during a period when an ignition switch (not shown) is turned on.

  First, in step 100, sampling is performed by inputting a detection signal from the vibration sensor 5.

  Thereafter, the process proceeds to step 110, and a filter process is executed in which the detection signal of the vibration sensor 5 sampled in step 100 is passed through a bandpass filter. Of the ECU 30 for detecting brake vibration, the part that executes this process corresponds to the filter processing means.

  The band-pass filter here extracts components in the resonance frequency band of the steering system, and removes even if vibrations irrelevant to the brake vibrations are detected by the vibration sensor 5. . Note that the resonance frequency band of the steering system here is confirmed to be a low frequency band of about 10 to 15 Hz, for example, according to experiments.

  Next, in step 120, it is determined whether or not the timing at which the detection signal of the current vibration sensor 5 was obtained was 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. The detection signal of the vibration sensor 5 obtained during the operation is handled as data during braking.

  If a negative determination is made in this step, it is assumed that brake vibration does not occur unless braking is being performed, and the process returns to step 100 again and the above processes are repeated.

  On the other hand, if an affirmative determination is made in this step, the process proceeds to step 130 where an averaging process is executed. Of the ECU 30 for detecting brake vibration, the part that executes this process corresponds to the gain calculation means.

  The average value S corresponds to an average of gains of detection signals from the vibration sensor 5. In order to remove noise components and offset components due to acceleration / deceleration of the wheels, this average value S is obtained by adding a gain from the value after passing through the band-pass filter of the detection signal of the vibration sensor 5 obtained by past sampling, The average value is obtained.

  Since the detection signal after passing through the bandpass filter becomes a signal that changes positively and negatively around 0, the gain is a general method, for example, an amplitude amount at an arbitrary time or an integrated value of squares, etc. Sought by.

  Then, it progresses to step 140 and a gain correction process is performed. Of the ECU 30 for detecting brake vibration, the part that executes this processing corresponds to the correcting means. The gain correction process is to correct the gain of the detection signal of the vibration sensor 5, and here, the average value S of the gain is corrected. First, a method for correcting the gain of the detection signal of the vibration sensor 5 will be described.

  It has been confirmed by the present inventors that the gain of the detection signal of the vibration sensor 5 varies according to the vehicle speed. Specifically, the brake vibration is maximized when a resonance phenomenon occurs when the resonance frequency of the steering system coincides with the primary or secondary rotation frequency of the wheel, and the gain is the vehicle speed at which the maximum is achieved. Decreases gradually as a standard.

  FIG. 3 shows this state, and FIG. 3 (a) shows a change in gain when there is partial wear that requires alarming to the disk rotor, FIG. 3 (b). ) Shows a change in gain when uneven wear is not so much generated in the disk rotor.

  The vehicle speed at which the resonance phenomenon occurs when the steering system and the rotation primary or secondary rotation of the wheels coincide with each other is determined by the vehicle, and is, for example, about 100 km / h or about 50 km / h. As can be seen by comparing FIG. 3 (a) and FIG. 3 (b), the gain of the detection signal increases or decreases depending on the degree of uneven wear in the disc brake. It is the vehicle speed. When the vehicle speed increases or decreases around the vehicle speed at which this resonance phenomenon occurs (zero), the gain of the detection signal decreases as can be seen from FIGS. 3 (a) and 3 (b).

  For this reason, if the occurrence of brake vibration is detected when the gain of the detection signal is greater than or equal to the brake vibration determination threshold, the gain of the detection signal varies depending on the vehicle speed, so the brake vibration can be accurately detected. It becomes impossible to detect the occurrence of.

  For example, if the disc rotor is worn to an alarm level, the gain will peak at the vehicle speed at which the resonance phenomenon occurs. If the vehicle speed deviates from the vehicle speed, the gain may decrease and the brake vibration determination threshold value may not be exceeded. In such a case, the occurrence of brake vibration cannot be detected.

  On the other hand, when the disc rotor is not worn enough to be an alarm target, the resonance phenomenon occurs even if the gain does not exceed the brake vibration determination threshold when it deviates from the vehicle speed at which the resonance phenomenon occurs. If the vehicle speed, the gain may increase and exceed the brake vibration determination threshold. Even in such a case, the occurrence of brake vibration cannot be detected.

  For this reason, a gain reduction rate (ratio) indicating how much the gain of the detection signal is reduced with respect to the peak is calculated according to how much the vehicle speed deviates from the vehicle speed at which the resonance phenomenon occurs, and the reduction The detection signal gain can be increased to the same level as the vehicle speed at which the resonance frequency is generated (hereinafter referred to as the resonance vehicle speed) by raising the rate according to the rate, for example, by multiplying the obtained gain by the reciprocal of the decrease rate. It becomes. In this way, even if the vehicle speed when the detection signal of the vibration sensor 5 is deviated from the resonance vehicle speed, the occurrence of brake vibration is detected based on the gain having the same magnitude as that at the resonance vehicle speed. It becomes possible.

  However, as shown in FIGS. 3A and 3B, when the deviation from the resonance vehicle speed is, for example, ± 40 km / h or more, even if the degree of uneven wear in the disc brake is different, the gain of the detection signal changes almost. Not.

  For this reason, if the above correction is performed until the vehicle speed when the detection signal of the vibration sensor 5 is largely deviated from the resonance vehicle speed, for example, regardless of the degree of uneven wear of the disc brake, In all cases, there is a possibility that the brake vibration cannot be accurately detected. For example, the gain of the detection signal becomes as large as the gain when uneven wear occurs as the alarm signal becomes an alarm target.

  Therefore, for example, a range of ± 40 km / h from the resonance vehicle speed is defined as the correction application range, and if the vehicle speed when the detection signal of the vibration sensor 5 is within the correction application range, the gain correction is performed. If it is out of range, it is preferable not to perform gain correction.

  FIG. 3C is a map showing the correction coefficient (magnification) when the range of ± 40 km / h from the resonance vehicle speed is defined as the correction application range as described above. The gain reduction rate is experimentally determined for each vehicle speed. And the reciprocal of the rate of decrease. For example, if the gain peak in FIG. 3 (a) is a and the gain when the deviation from the resonance vehicle speed is +35 km / h is b, the correction factor for the vehicle speed that is +35 km / h deviation from the resonance vehicle speed is obtained as a / b. It is.

  It is possible to perform gain correction using such a map. Therefore, if such a map is stored in advance in the ROM of the ECU 30 for detecting brake vibration, the correction coefficient can be obtained using this map when the gain is corrected.

  Here, an example is given in which the gain reduction rate is calculated as to how much the gain of the detection signal decreases with respect to the peak, and the gain is corrected by multiplying the inverse thereof. It is also possible to perform gain correction by obtaining a gain reduction amount indicating how much the gain of the detection signal is reduced with respect to the peak and adding the reduction amount.

  Based on such a correction method, the gain is corrected. FIG. 4 is a flowchart showing details of the gain correction processing in step 140 of FIG.

  As shown in this figure, first, in step 200, the average vehicle speed Vave when the detection signal of the vibration sensor 5 used in the averaging process in step 130 in FIG. 2 is obtained is calculated.

  As the vehicle speed at this time, the wheel speeds of the wheels FL, FR, RL, and RR may be used as they are, but a general method for obtaining the vehicle speed from the wheel speed (a method using the largest of the wheel speeds, Or a method using three average values excluding the slowest), and when the vehicle speed is obtained from another ECU mounted on the vehicle, information is obtained from the ECU. May be. 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. Of the ECU 30 for detecting brake vibration, the part for obtaining the vehicle speed corresponds to the vehicle speed detecting means.

  Next, in step 210, a difference dV (= resonance vehicle speed−Vave) from the resonance vehicle speed of the average vehicle speed Vave obtained in step 200 is obtained. The resonant vehicle speed at this time may be either 100 km / h or 50 km / h described above.

  Then, the process proceeds to step 220, and it is determined from the difference dV obtained in step 210 whether or not the average vehicle speed Vave is within the correction application range. As described above, the correction application range is, for example, a range of ± 40 km / h from the resonance vehicle speed. Here, if the difference dV does not exceed ± 40 km / h, an affirmative determination is made, and if it exceeds, a negative determination is made. Is done.

  If a negative determination is made in this step, it is not preferable to detect the brake vibration based on the gain of the detection signal obtained this time (in the present embodiment, the average value S). Proceeding to 160, the average value S obtained this time is cleared and the processing is completed.

  On the other hand, if an affirmative determination is made in this step, the process proceeds to step 230, and a correction coefficient is set so as to detect the brake vibration based on the gain of the detection signal obtained this time (average value S in this embodiment). K is read. The correction coefficient K is read using the map shown in FIG. 3C described above, and the correction coefficient K corresponding to the difference dV obtained in step 210 is extracted from the map.

  Then, the process proceeds to step 240, and the correction value of the average value S corresponding to the correction value of the gain of the detection signal is obtained by multiplying the average value S previously obtained in step 130 of FIG. S ′ (= S × K) is obtained.

  When the correction value S ′ is obtained in this way, the gain correction process is completed. Therefore, the process proceeds to step 150 in FIG. 2 to determine whether or not the correction value S ′ obtained in the gain correction process is equal to or greater than the brake vibration determination threshold value. Of the ECU 30 for detecting brake vibration, the part that executes this processing corresponds to the brake vibration detecting 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 160. After the average value S and the correction value S 'used this time are cleared, the process is completed. If an affirmative determination is made in this step, it is determined that brake vibration has occurred, the process proceeds to step 170, 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 gain of the detection signal of the vibration sensor 5 is corrected according to the vehicle speed, and the occurrence of brake vibration is detected using the corrected gain. I am doing so. For this reason, it is possible to detect the brake vibration more accurately.

(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 present embodiment, the gain of the detection signal of the vibration sensor 5 is corrected by a correction method different from that in the first embodiment.

  As described above, in the first embodiment, since the gain of the detection signal of the vibration sensor 5 varies according to the vehicle speed, the gain is corrected according to the vehicle speed. On the other hand, in this embodiment, since the gain of the detection signal of the vibration sensor 5 varies according to the braking torque, the gain is corrected according to the braking torque. That is, the present embodiment is obtained by changing the process executed in step 140 of FIG. 2 with respect to the first embodiment.

  Hereinafter, a method for correcting the gain of the detection signal of the vibration sensor 5 in the present embodiment will be described.

  It has been confirmed by the present inventors that the gain of the detection signal of the vibration sensor 5 varies depending on the braking torque. FIG. 5 shows the relationship between the braking torque and the gain of the detection signal of the vibration sensor 5 when the disc rotor is subjected to uneven wear that is an alarm target. However, since it is difficult to detect the braking torque itself, the relationship between the gain and the deceleration G used when estimating the braking torque is examined here.

  As shown in this figure, when the deceleration G is, for example, about 0.15 to 0.19 G (particularly 0.17 G), the gain of the detection signal of the vibration sensor 5 has a peak. Then, the gain of the detection signal of the vibration sensor 5 decreases according to the fluctuation of the deceleration G with this peak as a boundary.

  Therefore, the fluctuation of the braking torque is detected on the basis of the torque at which the gain of the vibration sensor 5 reaches the peak (hereinafter referred to as gain peak torque) among the braking torque, as in the vehicle speed shown in the first embodiment. Find the gain reduction rate (ratio) that indicates how much the signal gain falls with respect to the peak, raise it according to the reduction rate, for example, multiply the obtained gain by the reciprocal of the reduction rate By doing so, it is possible to increase the gain of the detection signal in the same way as the gain peak torque. In this way, even if the braking torque when the detection signal of the vibration sensor 5 is obtained deviates from the gain peak torque, the occurrence of the brake vibration is generated based on the gain having the same magnitude as that at the gain peak torque. Can be detected.

  However, for example, if the deceleration G is within the range of 0.13 to 0.21 G, the gain of the detection signal of the vibration sensor 5 differs depending on the degree of partial wear, but if the deceleration G is outside this range, the gain changes significantly. Disappear.

  Therefore, if the above correction is performed until the braking torque when the detection signal of the vibration sensor 5 is largely deviated from the gain peak torque, for example, depending on the degree of uneven wear of the disc brake. However, in all cases, there is a possibility that the brake vibration cannot be accurately detected. For example, the gain of the detection signal becomes as large as the gain when uneven wear occurs as the alarm signal becomes an alarm target.

  Therefore, for example, a range of ± 0.04 G is defined as a correction application range centered on the deceleration G corresponding to the gain peak torque, and the braking torque when the detection signal of the vibration sensor 5 is obtained is applied to this correction. When it is within the range, it is preferable to correct the gain, and when it is out of the range, it is preferable not to perform the gain correction.

  FIG. 5B shows the correction coefficient (magnification) when the range of the deceleration G (here 0.17G) to ± 0.04G corresponding to the gain peak torque is defined as the correction application range. This map is created by experimentally determining the gain reduction rate for each deceleration G and calculating the reciprocal of the reduction rate, as in the first embodiment.

  It is possible to perform gain correction using such a map. Therefore, if such a map is stored in advance in the ROM or the like of the ECU 30 for detecting brake vibration, the correction coefficient can be obtained using this map when performing gain correction.

  Here, an example is given in which the gain reduction rate is calculated as to how much the gain of the detection signal decreases with respect to the peak, and the gain is corrected by multiplying the inverse thereof. It is also possible to perform gain correction by obtaining a gain reduction amount indicating how much the gain of the detection signal is reduced with respect to the peak and adding the reduction amount.

  Based on such a correction method, the gain is corrected. FIG. 6 is a flowchart showing details of the gain correction processing in step 140 of FIG.

  As shown in this figure, first, in step 300, the average value (average braking torque) Fave of the braking torque when the detection signal of the vibration sensor 5 used in the averaging process of step 130 in FIG. Calculated. Of the ECU 30 for detecting brake vibration, the part that executes this process corresponds to the brake torque detecting means.

  As the braking torque at this time, for example, when a target braking torque is obtained in a brake ECU (not shown), the value may be used, or braking estimated from the wheel cylinder pressure and deceleration G of each wheel. Torque may be used, but in the present embodiment, the deceleration G is used. Note that the method for estimating the braking torque from the wheel cylinder pressure and the deceleration G is generally known from the past, and thus the description thereof is omitted here.

  Next, in step 310, it is determined whether or not the average braking torque Fave obtained in step 300 is within the correction application range. As described above, the correction application range is, for example, a range of ± 0.04 G around the deceleration G corresponding to the gain peak torque (that is, 0.13 to 0.21 G as shown in FIG. 5B). ), A positive determination is made within this range, and a negative determination is made outside the range.

  If a negative determination is made in this step, it is not preferable to detect the brake vibration based on the gain of the detection signal obtained this time (in the present embodiment, the average value S). Proceeding to 160, the average value S obtained this time is cleared and the processing is completed.

  On the other hand, if an affirmative determination is made in this step, the process proceeds to step 330, where a correction coefficient is used to detect the brake vibration based on the gain (average value S in the present embodiment) of the detection signal obtained this time. K is read. The correction coefficient K is read using the map shown in FIG. 5B described above, and the correction coefficient K corresponding to the deceleration G corresponding to the average braking torque Fave obtained in step 310 from the map. This is done by extracting

  Then, the process proceeds to step 340, and the correction value of the average value S corresponding to the correction value of the gain of the detection signal is obtained by multiplying the average value S previously obtained in step 130 of FIG. S ′ (= S × K) is obtained.

  When the correction value S ′ is obtained in this way, the gain correction process is completed. Therefore, the process proceeds to step 150 in FIG. 2, and the brake vibration detection determination is performed by the same method as in the first embodiment.

  As described above, according to the brake vibration detection device 1 of the present embodiment, the gain of the detection signal of the vibration sensor 5 is corrected according to the braking torque, and the occurrence of brake vibration is detected using the corrected gain. Like to do. For this reason, it is possible to detect the brake vibration more accurately.

(Third embodiment)
A third embodiment of the present invention will be described. The brake vibration detection device 1 of the present embodiment also 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 present embodiment, the gain of the detection signal of the vibration sensor 5 is corrected by a correction method different from that in the first embodiment. Specifically, in this embodiment, since the gain of the detection signal of the vibration sensor 5 varies according to the temperature of the disk rotor, the gain is corrected according to the temperature of the disk rotor. That is, this embodiment is also a modification of the process executed in step 140 in FIG. 2 with respect to the first embodiment.

  Hereinafter, a method for correcting the gain of the detection signal of the vibration sensor 5 in the present embodiment will be described.

  It has been confirmed by the present inventors that the gain of the detection signal of the vibration sensor 5 varies depending on the temperature of the disk rotor. FIG. 7A shows the relationship between the temperature of the disk rotor and the gain of the detection signal of the vibration sensor 5 in the case where uneven wear that is an alarm target occurs in the disk rotor.

  As shown in this figure, when the temperature of the disk rotor rises to a predetermined temperature or higher, the gain of the detection signal of the vibration sensor 5 peaks. And at temperatures below that, it gradually decreases.

  Therefore, the temperature at which the gain of the vibration sensor 5 reaches a peak (hereinafter referred to as the gain peak temperature) among the temperatures of the disk rotor, as well as the vehicle speed shown in the first embodiment, with respect to fluctuations in the temperature of the disk rotor. As a reference, a gain reduction rate (ratio) indicating how much the gain of the detection signal is reduced with respect to the peak is obtained and raised according to the reduction rate, for example, a reduction rate with respect to the obtained gain. It is possible to increase the gain of the detection signal in the same way as the gain peak temperature. In this way, even if the temperature of the disk rotor when the detection signal of the vibration sensor 5 is deviated from the gain peak temperature, the brake vibration is based on the gain having the same magnitude as that at the gain peak temperature. It is possible to detect the occurrence of this.

  FIG. 7B is a map showing the correction coefficient (magnification) with respect to the gain peak temperature as described above. Similar to the first embodiment, the gain reduction rate is experimentally obtained for each temperature, and the reduction is obtained. It was created by finding the reciprocal of the rate.

  It is possible to perform gain correction using such a map. Therefore, if such a map is stored in advance in the ROM or the like of the ECU 30 for detecting brake vibration, the correction coefficient can be obtained using this map when performing gain correction.

  Here, an example is given in which the gain reduction rate is calculated as to how much the gain of the detection signal decreases with respect to the peak, and the gain is corrected by multiplying the inverse thereof. It is also possible to perform gain correction by obtaining a gain reduction amount indicating how much the gain of the detection signal is reduced with respect to the peak and adding the reduction amount.

  Based on such a correction method, the gain is corrected. FIG. 8 is a flowchart showing details of the gain correction processing in step 140 of FIG.

  As shown in this figure, first, in step 400, the average temperature Tave of the temperature of the disk rotor when the detection signal of the vibration sensor 5 used in the averaging process of step 130 in FIG. 2 is obtained is calculated. . Of the ECU 30 for detecting brake vibration, the part that executes this process corresponds to the temperature detecting means.

  The temperature of the disk rotor at this time may be detected by a temperature sensor using infrared rays or the like. However, the number of times of braking and the amount of deceleration (accumulated value of deceleration) per arbitrary time can be used. May be converted into the temperature of the disk rotor, or these may be used directly as parameters.

  For example, when the temperature of the disk rotor cannot be measured directly, as a method of estimating it, basically, the relationship between the amount of deceleration of the vehicle (amount of kinetic energy converted into thermal energy) and temperature by the brake Although the method to obtain experimentally is simple, there is a case where the disk rotor is stored even if the vehicle does not decelerate like a downhill. Accordingly, the wheel cylinder pressure and the time when the wheel cylinder pressure is applied, or the number of times of braking and the time can be replaced. Since the heat stored in this way is dissipated over time, the air-cooling characteristics for each vehicle type are obtained in advance, and based on this, the temperature is added (heat storage) when the brake is turned on, and the temperature is subtracted when the brake is turned off. By performing a calculation such as (heat dissipation), the current temperature can be estimated.

  In step 410, the correction coefficient K is read in order to detect the brake vibration based on the gain of the detection signal obtained this time (average value S in this embodiment). The correction coefficient K is read using the map shown in FIG. 7B described above, and the correction coefficient K corresponding to the average temperature Tave obtained in step 400 is extracted from the map. .

  Then, the process proceeds to step 420, and the correction value of the average value S corresponding to the correction value of the gain of the detection signal is obtained by multiplying the average value S previously obtained in step 130 of FIG. S ′ (= S × K) is obtained.

  When the correction value S ′ is obtained in this way, the gain correction process is completed. Therefore, the process proceeds to step 150 in FIG. 2, and the brake vibration detection determination is performed by the same method as in the first embodiment.

  As described above, according to the brake vibration detection device 1 of the present embodiment, the gain of the detection signal of the vibration sensor 5 is corrected according to the temperature of the disk rotor, and brake vibration is generated using the corrected gain. Is to be detected. For this reason, it is possible to detect the brake vibration more accurately.

(Other embodiments)
In the first embodiment, the predetermined vehicle speed range has been described by taking, for example, a range of about 100 km / h ± 40 km / h or about 50 km / h ± 40 km / h as an example. Frequency) is about 100 km / h, and the secondary resonance frequency (rotational secondary resonance frequency) is about 50 km / h. These are given as examples. The same can be said for this. However, in this case, the resonating vehicle speed becomes a considerably low value, and the gain of the vibration sensor 5 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.

  In the first to third embodiments described above, different parameters are used for correcting the gain of the detection signal of the vibration sensor 5, but a plurality of these parameters can be used in combination.

  In the first to third embodiments, the vibration sensor 5 is used to detect the brake vibration. However, this includes a brake vibration component in which the detection signal of the vibration sensor 5 varies according to the brake vibration. This is because a gain related to brake vibration (vibration gain) can be obtained from this, so long as the detection signal includes a brake vibration component. For example, as shown in the above-mentioned Patent Document 1, the brake vibration may be detected by obtaining the vibration gain from the brake hydraulic pressure detection signal.

  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 a flowchart of the brake vibration detection process which ECU of the brake vibration detection apparatus shown in FIG. 1 performs. (A) is a diagram showing a change in gain when uneven wear has to occur for the disk rotor, and (b) is that uneven wear occurs with respect to the disk rotor. The figure which showed the change of the gain when not doing, (c) is the figure which showed the relationship between a vehicle speed and a correction coefficient. 3 is a flowchart showing details of a gain correction process included in the brake vibration detection process shown in FIG. 2. (A) is the figure which showed the change of the gain when the partial wear which has to alert | report to a disk rotor has generate | occur | produced, (b) shows the relationship between the deceleration G and a correction coefficient. FIG. It is the flowchart which showed the detail of the gain correction process included in the brake vibration detection process performed by ECU of the brake vibration detection apparatus of 2nd Embodiment of this invention. (A) is a diagram showing a change in gain in the case where partial wear has occurred so as to warn the disk rotor, and (b) is a relationship between the temperature of the disk rotor and a correction coefficient. FIG. It is the flowchart which showed the detail of the gain correction process included in the brake vibration detection process performed by ECU of the brake vibration detection apparatus of 3rd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Brake vibration detection apparatus, 5 ... Vibration sensor, 10 ... Stop switch, 21-24 ... Wheel speed sensor, 25-29 ... Sensor rotor, 30 ... ECU for brake vibration detection, 40 ... Alarm device.

Claims (12)

A plurality of wheels (FL, FR, RL, RR) provided in the vehicle when it is detected that the vehicle is being braked by the braking detection means (10) for detecting whether or not the vehicle is braking. ) and the signal generating means for generating a detection signal including a brake vibration component (5) in each, and filtering means for passing said detection signal the signal generating means is generated in the band-pass filter (110), with said filtering means Gain calculation means (130) for obtaining an average value (S) of the vibration gain obtained by averaging the gain of the detection signal after the processing of
Correction means (140) that obtains a value of a parameter that is a variation factor of the average value of the vibration gain obtained by the gain calculation means, and that corrects the average value of the vibration gain based on the value of the parameter. )When,
Brake vibration detection means (150) for detecting occurrence of brake vibration depending on whether or not the average value of the vibration gain after correction by the correction means is equal to or greater than a predetermined brake vibration determination threshold value. A brake vibration detecting device. A plurality of wheels (FL, FR, RL, RR) provided in the vehicle when it is detected that the vehicle is being braked by the braking detection means (10) for detecting whether or not the vehicle is braking. ) Gain calculation means (130) for calculating a vibration gain based on the detection signal generated by the signal generation means (5) for generating a detection signal including a brake vibration component in each;
A correction means (140) for determining a value of a parameter that is a fluctuation factor of the vibration gain obtained by the gain calculation means, and correcting the vibration gain based on the value of the parameter;
Brake vibration detection means (150) for detecting the occurrence of brake vibration depending on whether the vibration gain after being corrected by the correction means is equal to or greater than a predetermined brake vibration determination threshold value;
Vehicle speed detecting means for determining the vehicle speed of the vehicle;
Parameters cause a change of the vibration gain is the vehicle speed, the correction means, characterized and to lube that is adapted to correct the vibration gain based on the vehicle speed obtained by the vehicle speed detecting means Rake vibration detector. In the case where the vibration gain reaches a peak when the vehicle speed reaches a predetermined vehicle speed, when the vehicle speed is an arbitrary vehicle speed obtained based on the relationship between the decrease rate or the decrease amount of the vibration gain at an arbitrary vehicle speed with respect to the peak vibration gain. Storage means for storing the relationship of correction values;
The correction means obtains the vehicle speed when the vibration gain is obtained by the gain calculation means from the vehicle speed obtained by the vehicle speed detection means, and sets the correction value at the vehicle speed at the arbitrary vehicle speed. The brake vibration detection device according to claim 2 , wherein the correction is performed from the relationship between the correction values, and the correction is performed using the calculated correction values. The correction means sets a predetermined speed range including the predetermined vehicle speed at which the vibration gain reaches a peak as a correction application range, and the vehicle speed when the vibration gain is obtained by the gain calculation means is the correction application range. The brake vibration detection device according to claim 3 , wherein the correction is performed only in a range. A plurality of wheels (FL, FR, RL, RR) provided in the vehicle when it is detected that the vehicle is being braked by the braking detection means (10) for detecting whether or not the vehicle is braking. ) Gain calculation means (130) for calculating a vibration gain based on the detection signal generated by the signal generation means (5) for generating a detection signal including a brake vibration component in each;
A correction means (140) for determining a value of a parameter that is a fluctuation factor of the vibration gain obtained by the gain calculation means, and correcting the vibration gain based on the value of the parameter;
Brake vibration detection means (150) for detecting the occurrence of brake vibration depending on whether the vibration gain after being corrected by the correction means is equal to or greater than a predetermined brake vibration determination threshold value;
Braking torque detection means for determining the braking torque of the vehicle;
The parameter that is a fluctuation factor of the vibration gain is a braking torque, and the correction means corrects the vibration gain based on the braking torque obtained by the braking torque detection means. you Lube rake vibration detection device. In the case where the vibration gain reaches a peak when it becomes a predetermined braking torque, an arbitrary value obtained based on the relationship between the decrease rate or the decrease amount of the vibration gain at an arbitrary braking torque with respect to the peak of the vibration gain Storage means for storing the relationship of the correction value when the braking torque of
The correction means obtains a braking torque when the vibration gain is obtained by the gain calculation means from the braking torque obtained by the braking torque detection means, and sets a correction value at the time of the braking torque as the arbitrary value. 6. The brake vibration detecting device according to claim 5 , wherein the correction is performed from the relationship between the correction values at the time of braking torque, and the correction is performed using the calculated correction values. The correction means sets a predetermined braking torque range including the predetermined braking torque at which the vibration gain reaches a peak as a correction application range, and the braking torque when the vibration gain is obtained by the gain calculation means is The brake vibration detection device according to claim 6 , wherein the correction is performed only in the correction application range. The brake vibration detecting device according to any one of claims 5 to 7 , wherein the braking torque detecting means detects a deceleration or a wheel cylinder pressure that estimates the braking torque. A plurality of wheels (FL, FR, RL, RR) provided in the vehicle when it is detected that the vehicle is being braked by the braking detection means (10) for detecting whether or not the vehicle is braking. ) Gain calculation means (130) for calculating a vibration gain based on the detection signal generated by the signal generation means (5) for generating a detection signal including a brake vibration component in each;
A correction means (140) for determining a value of a parameter that is a fluctuation factor of the vibration gain obtained by the gain calculation means, and correcting the vibration gain based on the value of the parameter;
Brake vibration detection means (150) for detecting the occurrence of brake vibration depending on whether the vibration gain after being corrected by the correction means is equal to or greater than a predetermined brake vibration determination threshold value;
Temperature detecting means for determining the temperature of the disk rotor mounted for each wheel;
The parameter that causes the fluctuation of the vibration gain is the temperature of the disk rotor, and the correction means corrects the vibration gain based on the temperature of the disk rotor obtained by the temperature detection means. features and be Lube rake vibration sensing device that. When the vibration gain has a peak when the disk rotor is at a predetermined temperature or higher, the vibration gain is obtained based on the relationship between the decrease rate or the decrease amount of the vibration gain at an arbitrary temperature with respect to the vibration gain peak. Storage means for storing the relationship of correction values at an arbitrary temperature
The correction means obtains the temperature of the disk rotor when the vibration gain is obtained by the gain calculation means from the temperature of the disk rotor obtained by the temperature detection means, and a correction value at the temperature. The brake vibration detection device according to claim 9 , wherein the correction is obtained from a relationship of the correction value at the arbitrary temperature, and the correction is performed using the obtained correction value. The correction means sets a predetermined temperature range including the predetermined temperature at which the vibration gain reaches a peak as a correction application range, and the temperature of the disk rotor when the vibration gain is obtained by the gain calculation means. The brake vibration detection device according to claim 10 , wherein the correction is performed only when the value is within the correction application range. The brake vibration detection device according to any one of claims 9 to 11 , wherein the temperature detection means detects a braking frequency or an amount of deceleration for estimating the temperature of the disk rotor.

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