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CN-121740456-B - Test method of brake calipers

CN121740456BCN 121740456 BCN121740456 BCN 121740456BCN-121740456-B

Abstract

The application provides a test method of a brake caliper, which comprises the steps of assembling the brake caliper to be tested to vibration equipment, connecting a piston working cavity of the brake caliper to be tested with a hydraulic pipeline, carrying out vibration test on the brake caliper to be tested through the vibration equipment, detecting the variation of brake fluid in the hydraulic pipeline when the vibration test is finished, increasing the vibration energy of the vibration equipment, repeating the vibration test until the variation of the brake fluid is detected to generate step-type change, and obtaining the anti-knocking capacity value of the piston of the brake caliper to be tested according to the vibration energy corresponding to the step-type change. According to the application, the vibration equipment and the hydraulic pipeline are utilized to dynamically simulate the road working condition of the whole vehicle, the critical point of piston anti-rebound is accurately monitored through the brake fluid variation in the process of increasing the vibration energy and repeating the vibration test, the problem of the disconnection between the experimental test and the road working condition of the whole vehicle is overcome, the anti-rebound capability of the piston can be accurately and efficiently evaluated, the dependence on the road test of the whole vehicle is reduced, and the development cost and the risk are reduced.

Inventors

  • ZHENG GUO
  • SUN XIAOLIANG

Assignees

  • 采埃孚汽车科技(张家港)有限公司

Dates

Publication Date
20260508
Application Date
20251203

Claims (13)

  1. 1. A method of testing a brake caliper comprising the steps of: Assembling a tested brake caliper to vibration equipment, and connecting a piston working cavity of the tested brake caliper with a hydraulic pipeline; performing vibration test on the tested brake caliper by using the vibration equipment, and detecting the variation of brake fluid in the hydraulic pipeline when the vibration test is finished; Increasing the vibration energy of the vibration equipment and repeating the vibration test until the step change of the brake fluid variation is detected; The method comprises the steps of starting a hydraulic pipeline before a first vibration test, detecting the brake fluid flow required by pushing a piston of a tested brake caliper from an initial position to a working position, recording the brake fluid flow as an initial fluid demand, starting the hydraulic pipeline after each vibration test, detecting the brake fluid flow required by pushing the piston of the tested brake caliper from the current position to the working position, recording the brake fluid flow as a test fluid demand, when the brake fluid change quantity is detected to generate step change, obtaining the piston stroke difference of the tested brake caliper according to the difference between the test fluid demand corresponding to the step change and the initial fluid demand, and comparing whether the difference between the brake fluid change quantity and the brake fluid change quantity is smaller than a set threshold value or not after the brake fluid change quantity is detected in each vibration test period; The hydraulic pipeline is internally provided with a bidirectional flowmeter, the brake fluid variation is an accumulated net flow value measured by the bidirectional flowmeter during vibration test, and the brake fluid flow is an accumulated positive flow value measured by the bidirectional flowmeter during the working of the hydraulic pipeline; the method comprises the steps of taking vibration energy as an abscissa and taking the variation of the brake fluid or the difference value of the liquid required by the test liquid and the initial liquid required by the test liquid as an ordinate, drawing a relation curve, and determining a turning point of changing the ordinate value in the relation curve from a stable state to an incremental state as a critical point of generating the step change; Obtaining the piston anti-knock-back capability value of the tested brake caliper according to the vibration energy corresponding to the step change, and The method comprises the steps of assembling a tested brake caliper to a whole vehicle to perform road condition test, obtaining a liquid requirement difference value required by the piston of the tested brake caliper to move from a static position to a working position before and after the road condition test, obtaining vibration energy corresponding to the liquid requirement difference value obtained by a vibration test and matched with the liquid requirement difference value obtained by the road condition test, establishing a correlation between road spectrum energy of the road condition test and the vibration energy of the vibration test, and establishing an evaluation data table containing characteristic parameters of the tested brake caliper, a piston anti-knocking capability value, the road spectrum energy and the liquid requirement difference value obtained by the road condition test according to the correlation.
  2. 2. The test method of claim 1, further comprising the steps of: Determining the magnitude relation between the piston anti-knock capability value of the new brake caliper and the piston anti-knock capability value of the existing brake caliper in the evaluation data table according to the characteristic parameters of the new brake caliper based on the influence of the characteristic parameters on the piston anti-knock capability value; the influence of the characteristic parameters on the piston anti-knock-back capability value is obtained based on a physical principle and/or an existing vibration test and/or an existing road condition test; determining that a liquid demand difference value obtained by road condition test of the new brake caliper is qualified under the condition that the piston anti-back-knocking capability value of the new brake caliper is larger than or equal to the piston anti-back-knocking capability value of the qualified brake caliper in the evaluation data table and the required road spectrum energy of the new brake caliper is smaller than or equal to the road spectrum energy of the qualified brake caliper; Under the condition that the piston anti-back-knocking capability value of the new brake caliper is smaller than that of the qualified brake caliper and larger than that of the unqualified brake caliper in the evaluation data table, carrying out road condition test on the new brake caliper to obtain a liquid demand difference value of the new brake caliper; When the piston anti-back-knocking capability value of the new brake caliper is larger than or equal to the piston anti-back-knocking capability value of the qualified brake caliper and the required road spectrum energy of the new brake caliper is larger than the road spectrum energy of the qualified brake caliper, carrying out road condition test on the new brake caliper to obtain a liquid requirement difference value of the new brake caliper; Determining that the liquid demand difference obtained by road condition test of the new brake caliper is unqualified under the condition that the piston anti-back-knocking capability value of the new brake caliper is smaller than or equal to the piston anti-back-knocking capability value of the unqualified brake caliper; The difference value of the liquid required amount of the qualified brake calipers is smaller than or equal to a set qualified standard, and the difference value of the liquid required amount of the unqualified brake calipers is larger than the qualified standard.
  3. 3. Test method according to claim 2, characterized in that in case the magnitude relation of the piston anti-back-knockdown capability value of the new brake caliper to the piston anti-back-knockdown capability values of the existing brake calipers in the evaluation data table cannot be determined, it further comprises the steps of: and performing vibration test on the new brake caliper to obtain a piston anti-knock capability value of the new brake caliper.
  4. 4. The test method of claim 1, wherein the vibration device is capable of vibrating along an X-axis and/or a Y-axis and/or a Z-axis; and when the tested brake caliper is subjected to vibration test, controlling the vibration equipment to vibrate along one or more coordinate axes so as to detect the piston anti-knock capability value of the tested brake caliper along the one or more coordinate axes.
  5. 5. The test method according to claim 1, wherein when the tested brake caliper is subjected to vibration test, the vibration device is controlled to perform sinusoidal vibration according to set vibration parameters including vibration frequency, acceleration and vibration time; Increasing the vibration energy of the vibration device, including increasing the acceleration of the sinusoidal vibration in accordance with a set step size; the method comprises the step of obtaining the piston anti-back-knocking capability value of the tested brake caliper, wherein the acceleration value of sinusoidal vibration is used as the piston anti-back-knocking capability value of the tested brake caliper.
  6. 6. Test method according to claim 1, characterized in that the operating position is configured as a critical position in which the piston of the brake caliper under test is in initial contact with the brake disc; and during the working period of the hydraulic pipeline, judging the starting point of the pressure value linear rising monitored by the pressure sensor as the position where the piston of the tested brake caliper reaches the working position.
  7. 7. Test method according to claim 1, characterized in that the actuation of the hydraulic circuit, which detects the brake fluid flow required to push the piston of the brake caliper under test from an initial position to a working position, noted as initial fluid demand, comprises: Repeating the steps of starting the hydraulic pipeline for a plurality of times and detecting the brake fluid flow required by pushing the piston of the tested brake caliper from the initial position to the working position; And when the fluctuation amplitude of the brake fluid flow detected for a plurality of times is smaller than a first threshold value, recording the brake fluid flow detected last time as the initial liquid demand.
  8. 8. Test method according to claim 1, characterized in that after the vibration test, the hydraulic circuit is activated to detect the brake fluid flow required to push the piston of the brake caliper under test from the current position to the operating position, noted as test fluid demand, comprising: Repeating the steps of starting the hydraulic pipeline for a plurality of times after the vibration test is finished and waiting for a plurality of times, and detecting the brake fluid flow required by pushing the piston of the tested brake caliper from the current position to the working position; and when the fluctuation amplitude of the brake fluid flow detected for a plurality of times is smaller than a second threshold value, recording the brake fluid flow detected for the first time as the test liquid demand.
  9. 9. The method of claim 1, wherein the step change is performed until a step change in the brake fluid amount is detected, and wherein the step change is performed until a difference in the fluid demand between the test fluid demand and the initial fluid demand is detected.
  10. 10. The method of testing as set forth in claim 1, wherein obtaining the piston stroke difference of the brake caliper under test based on the difference between the test demand corresponding to the step change and the demand of the initial demand includes: obtaining a piston stroke difference of the tested brake caliper according to a liquid requirement difference value between the test liquid requirement corresponding to the step change and the initial liquid requirement and an acting area of a brake master cylinder of the hydraulic pipeline; wherein the master cylinder of the hydraulic line is configured to provide brake fluid to the piston working chamber.
  11. 11. The method of testing as set forth in claim 1, wherein obtaining a difference in liquid demand required for the piston of the brake caliper under test to move from a rest position to an operating position before and after the road condition test includes: Before road condition testing, detecting a first liquid requirement amount required by the piston of the tested brake caliper to move from a static position to a working position, wherein the first liquid requirement amount is detected at least once and takes a value detected last time; after the road condition test is completed, detecting a second liquid requirement amount required by the piston of the tested brake caliper to move from a static position to a working position, wherein the second liquid requirement amount is detected at least once and takes a value detected for the first time; And calculating the difference value between the second liquid requirement and the first liquid requirement, and taking the difference value as the liquid requirement difference value required by the movement of the piston of the tested brake caliper from the static position to the working position before and after the road condition test.
  12. 12. The test method of claim 1, wherein the piston of the brake caliper is mated with the piston working chamber by a seal ring; The characteristic parameters comprise piston parameters and/or sealing ring parameters and/or piston working cavity parameters of the brake caliper; The piston parameters comprise the diameter of the piston and/or the clearance between the piston and a piston working cavity and/or the surface roughness of the piston, the sealing ring parameters comprise the interference of the sealing ring and/or the friction coefficient of the sealing ring and/or the depth of a mounting groove of the sealing ring, and the piston working cavity parameters comprise the rigidity of the piston working cavity and/or the surface roughness of the piston working cavity.
  13. 13. The test method according to claim 2, further comprising the steps of, in case the new brake caliper is subjected to a road condition test to obtain a difference in the liquid demand of the new brake caliper: And adding the characteristic parameters of the new brake calipers, the piston anti-knock-back capability value, the road spectrum energy and the liquid requirement amount difference obtained by road condition test into the evaluation data table.

Description

Test method of brake calipers Technical Field The application relates to the technical field of braking, in particular to a test method of a brake caliper. Background The brake caliper is knocked back (Knockback) by a piston of the brake caliper due to road vibration or the like, and the piston is pushed back into the brake caliper cylinder. The back-knocking can cause abnormal clearance between the piston and the brake disc, so that a driver can feel that the pedal has a longer idle stroke when braking next time, and the driver needs to step deeper to realize braking. At present, the evaluation of the back-knocking phenomenon of the brake calipers mainly depends on two methods, namely an experimental test and a whole vehicle road test. However, most of experimental tests are static tests, the working condition of the whole vehicle road cannot be accurately simulated, the whole vehicle road test has the disadvantages of high resource consumption, high cost and long period, and is usually carried out in the middle and later stages of the development stage, so that the risk of reworking is high. It should be noted that the information disclosed in the foregoing background section is only for enhancement of understanding of the background of the application and thus may include information that does not form the prior art that is already known to those of ordinary skill in the art. Disclosure of Invention The application provides a test method of a brake caliper, which can accurately and efficiently evaluate the anti-knock-back capability of a piston of the brake caliper with low cost. According to one aspect of the application, a test method of a brake caliper is provided, which comprises the steps of assembling the brake caliper to be tested to vibration equipment, connecting a piston working cavity of the brake caliper to be tested to a hydraulic pipeline, carrying out vibration test on the brake caliper to be tested through the vibration equipment, detecting the brake fluid change amount in the hydraulic pipeline when the vibration test is finished, increasing the vibration energy of the vibration equipment, and repeating the vibration test until the brake fluid change amount is detected to be subjected to step change, and obtaining a piston anti-knocking capability value of the brake caliper to be tested according to the vibration energy corresponding to the step change. The vibration equipment and the hydraulic pipeline are utilized to dynamically simulate the road working condition of the whole vehicle, so that the problem of disjoint between the experimental test and the road working condition of the whole vehicle is solved. The brake fluid change measured at the end of each vibration test characterizes the displacement degree of the piston compared with the initial position through the vibration test. In the process of increasing vibration energy and repeating vibration testing, the critical point of piston anti-knocking is accurately monitored through the variation of brake fluid. The critical point of step change of the brake fluid variation can be identified by means of drawing and observing inflection points, so that the piston anti-knock-back capability value of the tested brake caliper can be accurately obtained. By adopting the testing method provided by the application, the anti-knocking-back capability of the piston can be accurately and efficiently evaluated, the dependence on the whole vehicle drive test is reduced, and the development cost and risk are reduced. In some embodiments, the method for testing the brake calipers further comprises the steps of starting the hydraulic pipeline before the first vibration test, detecting the brake fluid flow required for pushing the piston of the tested brake calipers from the initial position to the working position, and recording the brake fluid flow required for pushing the piston of the tested brake calipers from the current position to the working position after each vibration test, and recording the brake fluid flow required for testing the brake calipers, wherein when the brake fluid change amount is detected to have step change, the piston stroke difference of the tested brake calipers is obtained according to the difference value of the test fluid required corresponding to the step change and the liquid required of the initial fluid. By measuring the liquid demand, the displacement of the piston can be quantified and correlated with the degree of piston knockback. According to the difference between the liquid required by the test corresponding to the step change and the initial liquid required and the acting area of the brake master cylinder of the hydraulic pipeline, the piston stroke difference can be obtained, and the displacement generated by the vibration test corresponding to the step change of the piston of the tested brake caliper, namely the degree of the back-knocking of the piston is represented. In some embodiments, the vibratio