JPH04305134A - Inspection method for antilock brake - Google Patents

Abstract

PURPOSE:To achieve a suitable inspection for judging quality of an antilock brake with a limited change in deceleration. CONSTITUTION:Dceleration during the braking of rollers where a wheel is placed is detected as torque. measurement is performed to determined a braking time (t) taken until the rollers stop from time t0 of starting the operation of a brake, the maximum torque Tmax1 generated until a set time ts passes from the t0 and the maximum torque Tmax 2 generated to the time t1 at which the rollers stop after the elapse of the ts. Then, it is judged whether the (t), the Tmax1 and the Tmax2 are in allowable ranges or not. This enables accurate judgement of whether an antilock control is operated normally or not even for an antilock braking with limited change in deceleration generated associated with an increase or decrease control of a braking pressure.

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. Regarding how to do it.

0002

[Prior art] Anti-lock brakes are
As seen in Publication No. 99879, etc., when the deceleration of a wheel exceeds a reference deceleration, the increase in brake pressure is stopped, and the brake is determined based on a pseudo vehicle speed determined from the rotational speed of each wheel. When the wheel speed is lower than the reference speed, reduce the brake pressure until the deceleration drops to the reference deceleration, and when the wheel speed exceeds the reference speed. Control is performed to increase brake pressure. Then, a peak change appears in the deceleration of the wheel as the brake pressure is increased/decreased, and when the wheel is placed on the roller and braking is performed, the deceleration of the roller also changes in a peak manner. Thus, by looking at the peak change in roller deceleration, it is possible to determine whether the anti-lock brake has operated normally.

0003

By the way, in rear wheel brakes, a proportioning control valve (hereinafter referred to as PCV) is installed in the brake hydraulic system to moderate the pressure increase characteristic in the region of brake pressure above a certain pressure. This makes it difficult for the wheels to lock.
The range of increase/decrease in brake pressure becomes smaller, and the roller deceleration does not show a large peak change that can be distinguished from changes in deceleration caused by minute slips between the wheels and rollers, and Similarly, even when the pressure is finely decelerated so that the wheel speed is decelerated at a constant deceleration that is approximately equal to the deceleration characteristic of the reference speed, no discernible peak change appears in the deceleration of the roller. In this case, it may be possible to make a pass/fail judgment based on the braking time taken from the start of brake operation until the roller stops, but even if the brake is operated in the normal braking state where anti-lock control does not work, When there is insufficient power, the braking time may fall within the permissible range, and the quality of the anti-lock brake cannot be determined from the braking time alone. In view of the above points, it is an object of the present invention to provide an inspection method suitable for determining the quality of anti-lock brakes in which changes in roller deceleration caused by brake pressure increase/decrease control are small.

0004

[Means for solving the problem] In order to achieve the above purpose,
The present invention provides a method for inspecting anti-lock brakes by driving a vehicle equipped with anti-lock brakes with its wheels mounted on rollers and operating the brakes when a predetermined speed is reached. In addition to measuring the braking time from the start point until the roller stops, the maximum deceleration of the roller that occurs within a predetermined set time from the start of brake operation is measured, and the measured braking time and maximum deceleration are measured. The present invention is characterized in that the quality of the anti-lock brake is determined by comparing the values with reference values set for each of the anti-lock brakes.

[0005]

[Operation] When the brake pressure increases due to brake operation, the rotational speed of the wheels decreases, and the rotational speed of the rollers that rotate at the same speed as the wheels also decreases, resulting in an increase in deceleration. If the brakes are normal, the wheel deceleration increases to a predetermined value within a set time from the start of brake operation, anti-lock control is started, and the wheel speed remains almost constant, matching the deceleration characteristics of the reference speed. The wheels or rollers are decelerated at a deceleration rate of , and the wheels or rollers come to a stop after a predetermined time. If the braking force is insufficient, the deceleration of the rollers will not increase to a predetermined value within a predetermined time from the start of brake operation, and if anti-lock control does not work, the deceleration will increase significantly. The quality of the anti-lock brake can be determined by looking at the maximum deceleration that occurred within the set time and the braking time. By the way, if there is a response delay or the like in brake pressure control, the fluctuation range of deceleration becomes large and the feeling of brake operation becomes worse. Therefore, it is desirable to determine whether the anti-lock brake's operating feeling is good or bad by checking whether the deceleration is within a predetermined allowable range after the set time elapses until the roller stops. In brakes with a PCV in the hydraulic system, the increase in deceleration is suppressed by the PCV effect, so you can calculate the maximum deceleration that occurred during that time without looking at all the changes in deceleration until the roller stops. You can judge the operating state by looking at it. In addition, with anti-lock brakes, it is common practice to cancel anti-lock control when the pseudo vehicle speed determined from the rotational speed of each wheel drops to a predetermined low speed, and to brake the wheels to a stop under normal braking conditions. During this stop, the elastic energy stored in the inertial system consisting of the wheels and rollers is released, and the deceleration of the rollers is temporarily reduced to below zero level. The amount of this decrease increases as the deceleration immediately before stopping increases, and thus it is possible to judge whether the stopping feeling is good or bad based on whether the amount of decrease in deceleration below the zero level is below a predetermined reference value. can.

[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, 11 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
are the changes in wheel rotational speed V, wheel deceleration ν, and brake pressure P when the rear wheel brake with PCV installed in the hydraulic system is normally anti-lock controlled,
4 shows changes in torque T detected by torque meter 7. When the brake pressure P rises to a predetermined value Ps at the start of brake operation, the brake pressure is gradually increased by the action of the PCV, and when the deceleration ν exceeds a predetermined set value νs, the brake pressure increase is stopped. , when the wheel speed V falls below the reference speed Vs determined based on the pseudo vehicle speed determined from the rotational speed of each wheel, the brake pressure is reduced until the deceleration ν becomes below νs, and the wheel speed V decreases to Vs. When the brake pressure exceeds Vo, the brake pressure is increased, and the above operation is repeated.Finally, when the pseudo vehicle speed drops to a predetermined low speed Vo, the anti-lock control is released and the wheels are braked in the normal brake state. Wheels and rollers stop. While the anti-lock control is being performed, the wheels are decelerated at a substantially constant deceleration that matches the deceleration characteristics of the reference speed Vs, and no large peak changes appear in the torque T. 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 once decreases 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), the torque detected by the torque meter 7 is sampled at unit time intervals for a predetermined period of time, for example, 4 seconds (S1), and then the sampling data is The information is read out serially (S2), and the time point when the torque exceeds a predetermined threshold level T0 is stored as the brake operation start time point t0 (S3, S4). Then t
When a predetermined set time ts (for example, 0.3 seconds) has elapsed from 0, the maximum torque among the torques read so far is stored as the initial maximum torque Tmax1 (S5, S
6). Next, it is determined whether the torque has fallen below the zero level (S7), and when it has fallen below the zero level, that point is stored as the roller stop time t1 (S8), and further after ts has elapsed and before t1. The maximum torque among the read torques is stored as maximum torque Tmax2 (S9). Next, t0
Calculate braking time t from the time difference between and t1 (S10),
It is determined whether the braking time t is within a predetermined tolerance range between the lower limit value tL and the upper limit value tH determined according to the deceleration characteristics of the reference speed (S11), and if it is within the tolerance range, the result is passed. If it is outside the range, NG data is created as a failure (S12). Also, Tmax1 is a predetermined lower limit value TL
1 and the upper limit value TH1 (S13), and if it is within the tolerance range, it is determined as a pass;
If it is outside the range, create NG data as a failure (S1
4), furthermore, Tmax2 is a predetermined lower limit value TL2 and upper limit value T
It is determined whether or not it is within the allowable range between H2 (S
15), if it is within the allowable range, it is judged as pass; if it is outside the range, it is judged as fail, and NG data is created (S16), then the above pass/fail judgment data is output (S17), and the torque waveform is printed out ( S18).

The above TL1 is set to a value corresponding to the deceleration at which anti-lock control is started, that is, the above-mentioned νs, and TH1 is set to a value corresponding to the maximum deceleration at which the wheels do not lock. When the brake pressure does not increase to TL1 after ts has elapsed, as shown by the dotted line a in Fig. 3(d), and when the anti-lock control does not work and the brake pressure increases rapidly, the dotted line b shows The torque exceeds TH1 at the time when t has elapsed, and it is determined whether Tmax1 is within the allowable range between TL1 and TH1, and whether the braking time t is within the allowable range between tL and tH. By determining whether or not the anti-lock control has been performed normally, it can be determined whether or not the anti-lock control has been performed normally. By the way, if a response delay occurs in brake pressure control due to air entering the hydraulic system, the wheel speed V will deviate greatly from the reference speed Vs as shown in FIG. 4(a), and as shown in FIG. 4(b). The fluctuation range of the torque increases, and the torque no longer falls within the above-mentioned allowable range between TL2 and TH2, which is determined based on the normal operating conditions of anti-lock control. In this case, it may be determined whether the torque at each point in time after ts has elapsed is within the allowable range, but in brakes with a PCV in the hydraulic system, fluctuations in deceleration are suppressed by the action of the PCV. In order to be
As described above, only Tmax2 is detected and it is determined whether or not this is within the allowable range. In addition, if the anti-lock control is released at a speed higher than the above V0 at which the anti-lock control is released, and the deceleration of the wheels immediately before stopping becomes large, the torque generated at the time of stopping will drop below the zero level. It is also possible to compare the amount of decrease -Tmax with a reference value and determine that the product has failed when the amount of decrease exceeds the reference value.

0010

As is clear from the above description, according to the invention of claim 1, even if the change in deceleration that occurs due to brake pressure increase/decrease control is small, the brake operation can be improved. By looking at the degree of increase in deceleration at the start and the braking time, it is possible to determine whether anti-lock control has been performed, and further, according to the inventions of claims 2 and 3, it is also possible to determine whether the brake operation feeling is good or bad. Now you can
Further, according to the invention of claim 4, it is possible to determine whether the feeling of the wheel is good or bad when the wheel is stopped.

[Brief explanation of drawings]

[Fig. 1] A plan view of an example of an inspection device used to carry out the method of the present invention.

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

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

[Figure 4] Diagram showing changes in wheel speed and torque waveform when brake anti-lock control is not performed accurately

[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. The braking time required from the start of brake operation until the roller stops is measured, and the maximum deceleration of the roller that occurs within a predetermined set time from the start of brake operation is measured, and the measured braking time and maximum deceleration are calculated. A method for inspecting an anti-lock brake, comprising: comparing the speed with reference values set for each to determine the quality of the anti-lock brake. 2. The anti-lock roller according to claim 1, wherein it is determined whether the deceleration of the roller is within a predetermined allowable range from when the set time has elapsed until the roller stops. How to inspect lock brakes. 3. The maximum deceleration of the roller that occurs after the set time elapses until the roller stops is measured, and it is determined whether this maximum deceleration is within a predetermined allowable range. The anti-lock brake inspection method according to claim 1, characterized in that: [Claim 4] A claim characterized in that the amount of decrease in deceleration of the roller that occurs when the roller is stopped to a zero level or less is determined, and it is determined whether or not this amount of decrease is less than a predetermined reference value. The method for inspecting anti-lock brakes according to item 1.