JPH04305133A - Inspection method and apparatus for antilock brake - Google Patents

Abstract

PURPOSE:To enable accurate judgment of quality of an antilock brake and facilitate the estimation of the cause of rejection. CONSTITUTION:A wheel is rotated being placed on rollers 11 and 12 and a brake is operated at a specified speed to measure braking time required from the starting of the operation of the brake to the stoppage of the rollers. Moreover, deceleration of the rollers is detected with a torque meter 7 as torque to measure the number of peaks and a peak value appearing in a torque waveform during the braking time. A monitoring circuit 8 judges the propriety of the braking time, the number of peaks and the peak value separately. The quality of an antilock brake can be judged accurately by entering a change in peak of the deceleration appearing associated with a increase or decrease control of a braking pressure into an inspection item. This also facilitates the estimation of the cause of deficiency from an acceptance pattern of the braking time, the number of peaks and the peak value.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention inspects the anti-lock brakes by driving a car equipped with anti-lock brakes with its wheels mounted on rollers and operating the brakes when a predetermined speed is reached. The present invention relates to a method and apparatus for performing the same.

0002

[Prior Art] Conventionally, as an inspection method of this kind, as disclosed in Japanese Utility Model Application No. 63-7345, the number of rotations of a roller on which a wheel is mounted is detected, and when the brake is applied, the number of rotations of the roller is the upper limit of a predetermined number of rotations. There is a known system that measures the deceleration time required for deceleration to reach a lower limit value and compares this deceleration time with a predetermined reference time to determine the quality of the anti-lock brake. Anti-lock brakes are Japanese Patent Application Publication No. 54
As seen in Publication No. 99879, etc., the wheel speed is determined by comparing the wheel speed with the reference wheel speed during braking, which is determined based on the approximate vehicle speed determined from the rotational speed of each wheel. Reduces brake pressure when speed drops below
Control is performed to increase brake pressure when the wheel speed exceeds the reference speed, and the above reference time is set according to the deceleration characteristics of the reference speed, and the required time is determined by comparing this reference time and the above deceleration time. The conventional technique described above determines whether or not the brakes have been controlled so that the deceleration characteristic is as follows.

0003

[Problem to be Solved by the Invention] By the way, even if an abnormality occurs in which the brake pressure is not controlled to increase or decrease as described above and the brake is operated in the normal braking state, the wheel speed will decrease if the braking force is insufficient. The deceleration may be performed with characteristics close to the required deceleration characteristics, and the deceleration time may fall within the allowable range of the reference time. Therefore, with the above-mentioned prior art, it is not possible to accurately determine the quality of the anti-lock brake. In view of the above points, it is an object of the present invention to provide an inspection method and apparatus that can accurately determine the quality of an anti-lock brake and easily estimate the cause of the failure.

0004

[Means for solving the problem] In order to achieve the above purpose,
The device of the present invention includes a roller on which a car wheel is placed, a means for detecting the deceleration of the roller, and a method of calculating the braking time required from the start of brake operation until the roller stops based on the detected deceleration. means for calculating the number of peaks of deceleration detected during a braking time and the peak value of each peak, with the peak when the deceleration shows a change of a predetermined level or more; The present invention is characterized by comprising means for comparing the peak number and the peak value with respective set reference values to determine the quality of the anti-lock brake.

[0005]

[Operation] During the inspection, the vehicle is driven with its wheels placed on rollers, and when the required speed is reached, the brakes are applied, and the deceleration of the rollers while the brakes are in operation is detected. When brake pressure is applied and the rotational speed of the wheel decreases, the rotational speed of the roller that rotates at the same speed as the wheel also decreases, and the point at which the brake starts to operate can be determined by the rise of deceleration from zero level. When the rollers come to a stop, the elastic energy stored in the inertial system consisting of the wheels and rollers is released, and the deceleration temporarily drops below the zero level, making it possible to determine the point at which the rollers stop. . Then, the braking time is calculated from the time difference between the two times, and the peak number and peak value of deceleration occurring during this braking time are also calculated. When the wheel speed falls below the reference speed and the brake pressure decreases, the deceleration of the wheels or rollers decreases and a maximum peak appears just before that. Therefore, the number of brake pressure increase/decrease controls can be detected from the peak number. Further, when the deceleration of the roller increases due to a response delay in the brake pressure reduction operation, the peak value of the deceleration also increases. Therefore, by comparing the braking time, peak number, and peak value with their respective reference values, the braking time, peak number, and peak value are calculated.
If all tests pass, it can be determined that the anti-lock brakes are operating normally. Furthermore, the cause of the failure can be estimated based on the pass/fail pattern of which of the three passes and which fails. Additionally, if the braking force is insufficient, the deceleration will rise slowly when the brakes begin to operate, whereas if the brake pressure increases rapidly in normal braking conditions, the deceleration will increase excessively when the brakes begin to operate. . In this case, the above abnormality can be detected by detecting the maximum value of deceleration that occurs within a predetermined set time from the start of brake operation, and determining whether this value is within a predetermined tolerance range. Can be detected.

[0006]

[Embodiment] Fig. 1 shows a brake inspection device, which includes a pair of left and right rollers 11, 11 for the front wheels, and a pair of left and right rollers 12, 12 for the rear wheels. roller 1
1 and 11, a gear box 31 connecting each roller 11 via a clutch 21, and a rear wheel roller 12;
A gearbox 32 connecting each of the rollers 12 via a clutch 22 is disposed between the gearboxes 3 and 12, and both gearboxes 3
1 and 32 are connected via the drive shaft 4, and when a car is run with each wheel mounted on each roller, the rotation of the front wheel, which is the driving wheel, causes the roller 11, clutch 21, gear box 31, and drive shaft 4 to be connected. gearbox 3
2, a clutch 22, and a roller 12 to rotate the rear wheels. Each roller 11, 12 is composed of a pair of front and rear divided rollers 1a, 1b connected via a belt 5 so as to rotate synchronously, and both divided rollers 1a, 1b.
The friction coefficient of the outer circumferential surface of the rollers 1a and 1b is set to be large, and the rotational inertia moments of both divided rollers 1a and 1b are set to be equal to each other and the total rotational inertia moment is slightly larger than the rotational inertia moment of each wheel. At the same time, each wheel is prevented from slipping substantially against each divided roller 1a, 1b. Further, a flywheel 6 is connected to the divided roller 1b on the rear side of each roller 11, 12, and a torque meter 7 is interposed between the divided roller 1b and the flywheel 6 to reduce the number of rollers 11, 12. The speed was detected as torque, and the detection signal from the torque meter 7 was input to a monitor circuit 8 consisting of a microcomputer to perform the tests described later. The rollers 11, 11 for the front wheels are provided on a fixed base 9, and the rollers 12, 12 for the rear wheels are provided on a sliding base 10 that can freely move back and forth.
a and a spline shaft 4b that fits into the spline shaft 4b, and the distance between the front wheel roller 11 and the rear wheel roller 12 can be adjusted according to the wheelbase of the vehicle by the movement of the slide table 10. I made it adjustable.

When inspecting the brakes, the vehicle is run with each wheel placed on each roller 11, 12, and when a predetermined speed is reached, the clutches 21, 2 of each roller 11, 12 are
2 so that the rollers 11 and 12 are rotated independently, and in this state, step on the brake pedal. Figure 3
shows changes in the torque T detected by the torque meter 7, the rotational speed V of the wheels, the changes in the deceleration ν of the wheels, and the changes in the brake pressure P when the anti-lock brake is working normally. The anti-lock brake stops increasing the brake pressure when the wheel deceleration ν exceeds a predetermined set value νs, and the wheel speed V is set at a reference speed V determined according to the required deceleration characteristics.
When the wheel speed V exceeds the reference speed Vs, the brake pressure is reduced, when the deceleration ν falls below the set value νs, the brake pressure reduction is stopped, and when the wheel speed V exceeds the reference speed Vs, the brake pressure is increased. It is configured to repeat the above operation. The torque T changes in accordance with the deceleration ν, and a peak appears in its waveform in accordance with the brake pressure increase/decrease control. Furthermore, when the rollers stop, the elastic energy stored in the inertial system consisting of the wheels, rollers, and flywheel is released, and the deceleration ν and the torque T temporarily decrease below the zero level.

The inspection process in the monitor circuit 8 is executed according to the procedure shown in FIG. To explain this in detail, when a brake start signal is input from a control panel (not shown), each roller 11
, 12 torque meters 7 are sampled at unit time intervals for a predetermined period of time, for example, 4 seconds (S1),
After that, the sampling data for each roller is read out in chronological order (S2), and the time when the torque reaches or exceeds a predetermined threshold level T0 is the brake operation start time t0.
(S3, S4). Next, it is determined whether the torque is below the zero level (S5), and while it is above the zero level, this is the maximum value for the torque value at each point in time, and after that, it is determined that the torque is at a predetermined level, for example, 0.8 kg・m or above. The time when the torque decreases is determined as the peak (S6), and when the torque is at the peak, the torque value is stored as the peak value (S7). When the torque becomes less than the zero level, that time is stored as the roller stop time t1 (S8). Furthermore, at the time of stopping, the torque rapidly drops below the zero level even without reducing the brake pressure, so the peak immediately before this cannot be equated with the peak that occurs due to brake pressure increase/decrease control; The previous peak is not counted. Next, the braking time t is calculated from the time difference between t0 and t1, and the number of peaks that occurred during the braking time is calculated from the number of stored peak values (S9), and the number of peaks, peak value, and braking time are respectively calculated. A pass/fail determination is made by comparing with a set reference value (S10, S11, S12). For example, the standard value of the number of peaks is set to "2", and if it is 2 or more, it is considered to be a pass,
If it is "0" or "1", it is considered a failure and NG data is created (S10a). The peak value and braking time are the lower limit values Tl, tl and upper limit values Th, th set respectively.
If it is within the tolerance range between the two, it is determined to be a pass, and if it is outside the tolerance range, it is determined to be a failure and NG data is created (S11a, S
12a).

FIG. 4 shows test results when a delay in brake pressure response occurs due to air intrusion into the hydraulic system, etc.
The change in brake pressure is delayed compared to the normal change in brake pressure shown by the dotted line in Figure 4(d), and the braking time passes, but the number of peaks (the peaks counted where marked with an x) fails. At the same time, the peak value exceeds the upper limit Th, resulting in a failure. The test results shown in Figure 5 show that after the wheel speed exceeded the reference speed during the first brake pressure reduction control, the braking force did not increase sufficiently even if the brake pressure was increased, and the reference speed was decelerated while remaining above the reference speed. This is a case where the wheel speed decreases at a deceleration close to the characteristic, and the braking time and peak value pass, but the peak number fails. In addition, when the braking force is absolutely insufficient, the braking time becomes longer and the wheel speed is slowly decelerated without falling below the reference speed, so that no peak occurs, and the braking time, number of peaks, and peak value All will fail. Figure 6 shows the test results when the anti-lock brake does not work and the wheels are suddenly braked. At this time, the wheels may move backward due to the inertial rotational force of the rollers and a second peak may appear. The number of peaks passes, but the braking time falls below the lower limit value tl, resulting in a failure, and the peak value exceeds the upper limit Th, resulting in a failure. In addition, if there is foreign matter such as dirt attached to the pad, it may be rubbed off by the brake disc when the brake pressure is maintained at a low pressure, that is, when the torque is below the lower limit. The torque decreases once and a peak appears just before that. This peak value is less than the lower limit value Tl, so that attachment of foreign matter can be detected. As described above, the cause of failure of the anti-lock brake can be estimated based on the pass/fail pattern of which of the braking time, peak number, and peak value passes and which fails.

[0010] By the way, it is known that a proportioning control valve (hereinafter referred to as PCV) is installed in the rear wheel brake hydraulic system to suppress an increase in brake pressure, thereby making it difficult for the rear wheels to lock. Due to the PCV effect, the rear wheels may be decelerated to a stop while maintaining a constant deceleration that is approximately equal to the deceleration characteristic of the reference speed. The torque change at this time is as shown by the solid line in Fig. 7,
Because the peak does not appear, even if the braking time passes,
The number of peaks will fail. Even when the braking force is insufficient, the braking time may pass but the peak number may fail, and if this continues, it cannot be determined whether the problem is due to the PCV effect or not. However, when the braking force is insufficient, as shown by the dotted line in Figure 7, the rise of torque at the beginning of brake activation becomes slow, and the normal time required from the start of brake activation until the deceleration increases to a predetermined value is slow. Torque does not increase to a predetermined value within a certain amount of time (for example, 0.3 seconds). Therefore, when the above-described pass/fail judgment of the braking time, peak number, and peak value is completed for all four wheels (S13), it is determined whether the braking time of the rear wheels is passed and the peak number is judged as fail. (
S14), when the number of peaks is “0” or when the number of peaks is “1”
”, if the peak value is acceptable, read the rear wheel sampling data again and search for the maximum value Tmax of torque generated within a predetermined set time (for example, 0.3 seconds) ts from the brake operation start time to. (S15), then Tma
It is determined whether or not x is within a predetermined tolerance range (lower limit Tsl, upper limit Tsh) (S16), and if it is, it is determined to be a pass; if it is not, it is determined to be a failure and NG data is created (S16a); Next, the pass/fail judgment data for each of the four wheels is output (S17), and the torque waveform for each wheel is also printed out (S18). In addition, in this example, Tma
Although the search determination for x is performed only for the rear wheels, it is needless to say that the present invention is not limited to this.

[0011]

As described above, according to the inventions of claims 1 and 3, it is possible to accurately determine whether the anti-lock brake is good or bad, and the cause of the failure can be easily estimated.
According to the fourth invention, it is possible to determine whether or not the braking force is insufficient based on the torque generated at the initial stage of brake operation.

[Brief explanation of drawings]

[Figure 1] Plan view of an example of the device of the present invention

[Figure 2]
Flowchart showing the execution program of the method of the present invention

[Figure 3] Diagram showing the torque waveform, wheel speed, wheel deceleration, and changes in brake pressure when the brakes operate normally.

[Figure 4] Diagram corresponding to Figure 3 in the case of brake pressure response delay

[Figure 5] Diagram corresponding to Figure 3 when braking force is insufficient

[Figure 6] Diagram showing the torque waveform when the normal brake state is reached

[Figure 7] Diagram showing the torque waveform on the rear wheel side

[Explanation of symbols]

11, 12 Roller 7 Torque meter, 8 Monitor circuit

Claims (4)

[Claims] Claim 1: A method of inspecting anti-lock brakes by driving a vehicle equipped with anti-lock brakes with its wheels on rollers and operating the brakes when a predetermined speed is reached. In addition to measuring the braking time required from the start of operation until the roller stops, the peak number of decelerations that occurred during the braking time and each peak is calculated when the roller deceleration shows a change of more than a predetermined level. The anti-lock brake is characterized in that the quality of the anti-lock brake is determined by measuring the peak value of the anti-lock brake and comparing the measured braking time, the number of peaks, and the peak value with respective set reference values. Inspection method. 2. The anti-lock brake system according to claim 1, further comprising: determining whether a maximum value of deceleration occurring within a predetermined set time from the start of brake operation is within a predetermined tolerance range. How to inspect lock brakes. [Claim 3] A roller on which a wheel of an automobile is placed, a means for detecting the deceleration of the roller, and a braking time required from the start of brake operation until the roller stops based on the detected deceleration. means for calculating the number of peaks of deceleration detected during a braking time and the peak value of each peak, with the peak when the deceleration shows a change of a predetermined level or more; 1. An anti-lock brake inspection device comprising means for comparing the peak number and the peak value with reference values set for each to determine the quality of the anti-lock brake. [Claim 4] A claim characterized in that means is provided for determining whether the maximum value of deceleration that occurs within a predetermined set time from the start of brake operation is within a predetermined tolerance range. The anti-lock brake inspection device according to item 3.