Piston sliding resistance test device and test method for brake caliper assembly

Abstract

The invention relates to the technical field of automobile part test devices, in particular to a piston sliding resistance test device and test method for a brake caliper assembly, and the device comprises a test bench; the sample piece clamping mechanism is used for clamping the caliper body and the piston; the driving measuring mechanism and the sample piece clamping mechanism are both perpendicular to the working table plate and can move relatively until the axis of the ejector rod coincides with the axis of the piston; the driving lead screw drives the ejector rod to push the piston to slide in the X forward direction relative to the caliper body through the force sensor. The driving screw rod is provided with a displacement sensor for recording a displacement value; the air supply mechanism is used for supplying air to the piston and pushing the piston to slide and reset to the initial position in the X negative direction relative to the caliper body. The controller generates a force-displacement curve in real time every time when the ejector rod pushes the piston. According to the piston sliding resistance test device and test method, the piston return resistance characteristic curve of the brake caliper assembly can be accurately and reliably measured.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile component testing devices, and in particular to a piston sliding resistance testing device and a testing method for a brake caliper assembly. Background Art

[0002] Currently, automotive braking systems are crucial to overall vehicle safety. The brake caliper assembly is a key component in the braking system, acting as the actuator. Its function is to propel the piston through hydraulic energy in the pipelines and master cylinder, thereby clamping the friction pads against the brake discs and achieving the vehicle's braking function. When the brakes need to be released, the brake fluid in the wheel cylinder flows back into the pipeline system, and the piston returns to its original position due to negative pressure and the push of other components.

[0003] Specifically, the brake caliper assembly primarily consists of a piston, a caliper body, and friction pads. When the friction pads clamp against the brake disc, braking is initiated. The process of the friction pads moving away from the disc is called return. This movement requires the caliper body, driven by the piston's return force, to quickly disengage the friction pads from the disc, releasing the vehicle's braking condition. If the piston's return resistance is excessive, the friction pads cannot disengage from the disc in a timely manner, creating a significant drag torque on the disc surface and generating significant heat. When this occurs, the heat generated by this drag torque accumulates while the vehicle is in motion, causing thermal degradation of the friction pad's braking performance and a rapid increase in the friction disc's temperature. This heat is then transferred from the disc to the tire via the wheel hub, increasing the risk of tire blowouts and posing a significant threat to vehicle safety. Disassembly and analysis of numerous vehicles with related faults confirms that excessive caliper body return resistance is a key cause of tire blowouts.

[0004] In the related art, the braking performance test of the brake caliper assembly is generally the main focus, and no test is involved in the related test of the piston sliding resistance during the return process. Furthermore, based on the structural characteristics of the automobile caliper body, the excessive resistance between the piston and the caliper body in the brake caliper assembly is the root cause of the failure. In fact, there are many factors that affect the piston sliding resistance of the brake caliper assembly, such as the design and processing accuracy of the piston and wheel cylinder mating surface, the piston sleeve return force, the wear of the piston surface, etc. Regardless of the number of influencing factors, the piston return resistance in the brake caliper assembly must ensure that the piston can return quickly and smoothly in the hydraulic brake system. On the one hand, the resistance peak should be controlled within a specified range during the entire piston return process. On the other hand, the resistance value should be a smooth curve during the return process, and no sudden changes in resistance should occur. Only in this way can the piston return quickly and smoothly.

[0005] Therefore, how to accurately, reliably, conveniently and intuitively measure the piston return resistance characteristic curve of the brake caliper assembly under simulated actual vehicle conditions is an issue that needs to be solved urgently. Summary of the Invention

[0006] The present application provides a brake caliper assembly piston sliding resistance test device and test method, which can accurately and reliably measure the brake caliper assembly piston return resistance characteristic curve.

[0007] In a first aspect, an embodiment of the present application provides a brake caliper assembly piston sliding resistance test device, comprising: a test bench including a workbench plate; Sample clamping mechanism, used to clamp the caliper body and piston; The drive and measurement mechanism comprises a push rod, a force sensor, and a drive screw, which are sequentially arranged on the same axis. The drive and measurement mechanism and the sample clamping mechanism are both perpendicular to the worktable and can move relative to each other until the axis of the push rod coincides with the axis of the piston. The drive screw drives the push rod through the force sensor to push the piston to slide in the positive X direction relative to the caliper body. The drive screw is provided with a displacement sensor that records its displacement value. An air supply mechanism is used to supply air to the piston and push the piston to slide relative to the caliper body in the negative X direction and return to the initial position; The controller has a signal connected to the displacement sensor and the force sensor. The controller generates a force-displacement curve in real time each time the push rod pushes the piston.

[0008] In combination with the first aspect, in one embodiment, the test bench further includes an air supply mechanism, which includes an air pump, an air cylinder, a pressure regulating valve and a pressure gauge connected in sequence through an air pipe, and the pressure gauge is connected to the cavity between the bottom wall of the piston and the wheel cylinder of the caliper body through a pipeline.

[0009] In combination with the first aspect, in one embodiment, an undercut guide rail is provided on the upper surface of the workbench, and the sample clamping mechanism includes an L-shaped support located at the bottom, and the L-shaped support is slidably connected to the undercut guide rail along the Y direction.

[0010] In combination with the first aspect, in one embodiment, the driving and measuring mechanism further includes a vertical mounting bracket and a horizontal movable support; the vertical mounting bracket is provided with a vertical screw structure, and the horizontal movable support is provided with a horizontal screw structure; The vertical mounting bracket is fixed vertically to the workbench; the push rod, force sensor, drive screw and displacement sensor are all arranged on the horizontal movable support; The horizontal screw rod structure and the vertical screw rod structure are vertically staggered and connected through a slider with a non-planar cross groove. The horizontal movable support slides along the X direction and the Z direction relative to the vertical mounting bracket through the horizontal screw rod structure, the vertical screw rod structure and the slider.

[0011] In combination with the first aspect, in one embodiment, the push rod and the force sensor are connected via a first sleeve with a semi-enclosed structure, and the driving screw and the force sensor are connected via a second sleeve with a semi-enclosed structure.

[0012] In combination with the first aspect, in one embodiment, the horizontally movable support is provided with an upward opening groove, and the driving screw, force sensor, and displacement sensor are all accommodated and arranged in the opening groove; an L bracket is also provided in the opening groove; the displacement sensor is installed at the bottom of the opening groove of the horizontally movable support, and the vertical plate of the L bracket is linked to the driving screw. During the movement of the driving screw, the horizontal plate of the L bracket drives the movement of the contacts on the displacement sensor.

[0013] In combination with the first aspect, in one embodiment, two position switches are respectively installed on both sides of the upper edge X of the opening slot of the horizontal movable support; when the push rod moves to the limit position, the position switch activates a protective alarm.

[0014] In combination with the first aspect, in one embodiment, the drive measuring mechanism further includes a servo motor, which is fixed to the side end of the horizontal movable support. The controller drives the lead screw and the force sensor forward through the servo motor, and moves the displacement sensor through the L bracket.

[0015] In combination with the first aspect, in one embodiment, the sample clamping mechanism further includes a transition plate and two slide plates, wherein the transition plate is mounted on the top of the L-shaped support; the bottom of the caliper body is rotatably connected to the center of the transition plate; The transition plate is provided with two protruding limit bolts, each slide plate has a long waist round hole, the top ends of the two slide plates are fixed to the caliper body, and the two limit bolts are respectively passed through the long waist round holes of the two slide plates; the caliper body adjusts its vertical angle relative to the transition plate according to the actual vehicle angle known in advance.

[0016] In a second aspect, an embodiment of the present application provides a test method based on the above-mentioned piston sliding resistance test device, comprising the following steps: The driving measuring mechanism and the sample clamping mechanism are relatively moved until the axis of the ejector rod coincides with the axis of the piston; Adjust the assembly angle of the caliper body in the sample clamping mechanism according to the known assembly angle of the actual vehicle; The air supply mechanism pushes the piston to an initial position; Close the air supply mechanism, drive the screw rod through the force sensor to drive the push rod to push the piston to slide in the positive X direction relative to the caliper body, simulating the piston return process. The controller generates the force-displacement curve in real time for the first time. The air supply mechanism resets the piston and the ejector rod pushes the piston repeatedly, and the controller generates force-displacement curves in real time multiple times.

[0017] The beneficial effects of the technical solutions provided in the embodiments of the present application include at least: 1. The piston sliding resistance test device of the present application has many advantages. On the one hand, the driving and measuring mechanism and the sample clamping mechanism are both perpendicular to the work table, and the two can move relative to each other until the axis of the push rod coincides with the axis of the piston. The relative position between the two can be flexibly adjusted on the work table to ensure that the push rod can apply force within the range of motion of the piston during the test. On the one hand, the force sensor, drive screw and push rod are on the same axis to ensure that the drive and measuring mechanism will not shift during the pushing process. In the process of pushing the piston, because the clearance between the piston and the caliper body is very small and the fitting accuracy is high, the coaxial accuracy requirements are high. The axis of the push rod coincides with the axis of the piston, which can prevent eccentric wear of the piston and eliminate measurement deviation.

[0018] On the one hand, the air supply mechanism is conducive to restoring the initial position. In order to ensure the accuracy of the measurement, multiple measurements are required. Compared with some technical solutions that require manual disassembly and manual reset, the pushing efficiency of this application corresponds to the actual piston return and reset efficiency, and multiple sets of force-displacement value curves can be quickly obtained.

[0019] During the test, the controller collects and monitors force and displacement values ​​in real time. After the test is complete, the ejector rod is automatically retracted and reset. Based on the collected data, a force-displacement curve is plotted in real time, quickly identifying resistance peaks and determining any sudden changes in resistance. If an abnormal sudden change or excessive resistance occurs during the test, the displacement value at that point can be used to quickly identify the point of increased resistance on the inside of the wheel cylinder of the piston and caliper body, providing precise location for product defect and troubleshooting.

[0020] 2. The piston sliding resistance test device of the present application resets the piston to its initial position through the air supply mechanism. The air pump, air cylinder, pressure regulating valve and pressure gauge can ensure stable air pressure and slowly and stably reset it to the initial position, ensuring the consistency of the initial position each time, thereby ensuring the consistency of the basic adjustment of the measurement data.

[0021] 3. The piston sliding resistance test device of the present application has an L-shaped support that is slidably connected to the inverted guide rail along the Y direction, and the horizontally movable support slides along the X and Z directions relative to the vertical mounting bracket through the horizontal screw structure, the vertical screw structure and the slider. The combination realizes flexible adjustment in the X, Y and Z directions, so that the push rod is aligned with the piston axis, providing a basis for simulating the actual piston return and effectively preventing eccentric wear. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0023] Figure 1 A general structural diagram of the sliding resistance test device provided in an embodiment of the present application; Figure 2 A schematic diagram of the structure of the sample clamping mechanism provided in an embodiment of the present application; Figure 3 for Figure 2 Left view of; Figure 4 A schematic diagram of the structure of the drive measurement mechanism provided in an embodiment of the present application; Figure 5 for Figure 4 Schematic diagram of the structure of the force sensor, displacement sensor, ejector rod, drive screw and two sleeves; Figure 6 for Figure 5 sectional view of Figure 7 A flowchart of a test method for a sliding resistance test device provided in an embodiment of the present application; In the picture: 100. Test bench; 101. Sample clamping mechanism; 102. Drive and measurement mechanism; 103. Air supply mechanism; 104. Test sample; 51. Air pump; 52. Air reservoir; 53. Pressure regulating valve; 54. Air pressure gauge; 56. Caliper body; 57. Piston; 58. Dust cover; 59. Air inlet; 11. Work table; 12. Undercut guide rail; 13. Bottom table; 21. L-shaped support; 22. Transition plate; 23. Slide plate; 31. Vertical mounting bracket; 32. Horizontal movable support; 33. Vertical screw structure; 34. Horizontal screw structure; 35. L bracket; 36. Force sensor; 36a. First boss; 36b. Second boss; 37. Displacement sensor; 38. Push rod; 39. First sleeve; 40. Second sleeve; 41. Servo motor; 42. Drive screw; 43. Position switch; 44. Fastening screw. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0025] The present application provides a brake caliper assembly piston sliding resistance test device and test method, which can accurately and reliably measure the brake caliper assembly piston return resistance characteristic curve.

[0026] Specifically, the brake caliper assembly mainly includes a piston, a caliper body and a friction plate. When the friction plate clamps the brake disc, the brake is applied. The process of the friction plate moving away from the brake disc is called return. When the friction plate moves away from the brake disc, the caliper body needs to be driven by the return force of the piston so that the friction plate can quickly disengage from the brake disc.

[0027] The piston return resistance in the brake caliper assembly must ensure that the piston can return quickly and smoothly in the hydraulic brake system. Two aspects need to be guaranteed. On the one hand, the resistance peak should be controlled within a specified range during the entire piston return process. On the other hand, the resistance value should be a smooth curve during the return process, and no sudden changes in resistance should occur. Only in this way can the piston be guaranteed to return quickly and smoothly.

[0028] The piston sliding resistance testing device of the present application is intended to obtain a curve that can reflect the resistance peak value and resistance smoothness.

[0029] like Figures 1 to 6 As shown, the present application discloses an embodiment of a piston sliding resistance test device for a brake caliper assembly, the piston sliding resistance test device comprising a test bench 100, a sample clamping mechanism 101, a drive measurement mechanism 102, an air supply mechanism 103 and a controller.

[0030] The test bench 100 includes a workbench 11 .

[0031] The sample clamping mechanism 101 is used to clamp a test sample 104 . The test sample 104 includes a caliper body 56 and a piston 57 .

[0032] The drive and measurement mechanism 102 includes a push rod 38, a force sensor 36, a drive screw 42, and a displacement sensor 37. The push rod 38, force sensor 36, and drive screw 42 are located on the same axis and are arranged in sequence. The drive and measurement mechanism and the sample clamping mechanism are both mounted vertically on the worktable 11, and the two can move relative to each other until the axis of the push rod 38 coincides with the axis of the piston 57. The drive screw 42 drives the push rod 38 through the force sensor 36 to push the piston 57 to slide in the positive X direction relative to the caliper body 56. The force sensor 36 reflects the thrust value in real time. The drive screw 42 is equipped with a displacement sensor 37 that records its displacement value. The displacement sensor 37 reflects the displacement value of the drive screw 42 in real time.

[0033] The air supply mechanism 103 is used to supply air to the piston 57 and push the piston 57 to slide along the negative X direction relative to the caliper body 56 to return to the initial position. Each time the push rod 38 completes a push, it will be restored to the initial position through the air supply mechanism 103.

[0034] The controller signal is connected to the displacement sensor 37 and the force sensor 36. The controller generates a force-displacement curve in real time when the push rod 38 pushes the piston 57. The force-displacement curve can be used to find the resistance peak and whether there is a sudden change in resistance.

[0035] It is worth noting that if Figure 2 The process of the push rod 38 pushing the piston 57 corresponds exactly to the process of the piston returning to its original position. Specifically, in the actual structure, the piston opening has inner and outer friction plates, and the brake disc is set between the inner and outer friction plates. When the piston is pushed, the caliper body, driven by the piston's return force, drives the friction plates to quickly disengage the brake disc.

[0036] It is worth noting that the piston 57 slides relative to the caliper body 56 along the negative X direction and resets to the initial position, wherein the initial position corresponds to the position of the piston 57 relative to the wheel cylinder of the caliper body 56 after the actual vehicle is braked.

[0037] The piston sliding resistance testing device of the present application has many advantages. On the one hand, the driving and measuring mechanism and the sample clamping mechanism are both perpendicular to the workbench 11, and the two can move relative to each other until the axis of the push rod 38 coincides with the axis of the piston 57. The relative position between the two can be flexibly adjusted on the workbench 11 to ensure that the push rod can apply force within the range of motion of the piston during the test. On the one hand, the force sensor, the drive screw 42 and the push rod are on the same axis to ensure that the driving and measuring mechanisms will not be offset during the pushing process. In the process of pushing the piston, because the clearance between the piston and the caliper body is very small and the fitting accuracy is high, the coaxial accuracy requirements are high. The axis of the push rod 38 coincides with the axis of the piston 57, which can prevent the piston from wearing unevenly and eliminate measurement deviations.

[0038] On the one hand, the air supply mechanism 103 is conducive to restoring the initial position. In order to ensure the accuracy of the measurement, multiple measurements are required. Compared with some technical solutions that require manual disassembly and reset, the pushing efficiency of this application corresponds to the actual piston return and reset efficiency, and multiple sets of force-displacement value curves can be quickly obtained.

[0039] During the test, the controller collects and monitors force and displacement values ​​in real time. Upon completion, the ejector rod automatically retracts and resets. Based on the collected data, a force-displacement curve is plotted in real time, quickly identifying resistance peaks and determining any sudden changes in resistance. If an abnormal sudden change or excessive resistance occurs during the test, the displacement value at that point can be used to quickly identify the point of increased resistance inside the wheel cylinder of the piston 57 and caliper body 56, providing precise location for product defect and fault troubleshooting.

[0040] like Figure 1 As shown, further, in one embodiment, the test bench also includes an air supply mechanism 103, which includes an air pump 51, an air cylinder 52, a pressure regulating valve 53 and a pressure gauge 54 connected in sequence through an air pipe, and the pressure gauge 54 is connected to the cavity between the bottom wall of the piston 57 and the wheel cylinder of the caliper body 56 through a pipeline.

[0041] The air pump 51 extracts and compresses air. The air reservoir 52 stores the compressed air. The pressure regulating valve 53 regulates the pressure to prevent excessive, insufficient, or large fluctuations in the compressed air pressure, maintaining a stable compressed air pressure. The barometer 54 monitors the air pressure to ensure that the pressure output by the piping system to the test specimen remains within the specified value, thus preventing pressure fluctuations from affecting the test results.

[0042] Preferably, the test bench also includes a bottom plate 13, and an installation space is formed between the bottom plate 13 and the work table 11. The air pump 51, air cylinder 52, pressure regulating valve 53 and pressure gauge 54 of the air supply mechanism 103 are arranged between the bottom plate 13 and the work table 11.

[0043] The piston sliding resistance testing device of the present application resets the piston to its initial position through the air supply mechanism 103. The air pump 51, air cylinder 52, pressure regulating valve 53 and pressure gauge 54 can ensure that the air pressure is stable and slowly and stably resets it to the initial position, ensuring the consistency of the initial position each time, and thus ensuring the consistency of the basic adjustment of the measurement data.

[0044] like Figure 1 and Figure 2 As shown, in one embodiment, an undercut guide rail 12 is provided on the upper surface of the workbench 11, and the sample clamping mechanism 101 includes an L-shaped support 21 at the bottom, which is slidably connected to the undercut guide rail 12 along the Y direction. Specifically, the Y direction mark is shown in FIG. Figure 3 .

[0045] Preferably, when the push rod 38 is actually pushed, the L-shaped support 21 and the workbench 11 are fixed by prescribed bolts, and when moving, the prescribed bolts are removed. The undercut guide rail 12 and the L-shaped support 21 can achieve three-dimensional Y-dimensional alignment.

[0046] like Figure 4 As shown, in one embodiment, the driving and measuring mechanism 102 further includes a vertical mounting bracket 31 and a horizontal movable support 32; the vertical mounting bracket 31 is vertically fixed to the workbench 11; the vertical mounting bracket 31 is provided with a vertical screw structure 33 along the vertical direction, and the horizontal movable support 32 is provided with a horizontal screw structure 34 along the horizontal direction.

[0047] The push rod 38 , the force sensor 36 , the drive screw 42 and the displacement sensor 37 are all arranged on the horizontal movable support 32 , and the push rod 38 , the force sensor 36 , the drive screw 42 and the displacement sensor 37 move along with the horizontal movable support 32 .

[0048] The horizontal screw rod structure 34 and the vertical screw rod structure 33 are vertically staggered and connected through a slider with unequal cross grooves. The horizontal movable support 32 slides along the X and Z directions relative to the vertical mounting bracket 31 through the horizontal screw rod structure 34, the vertical screw rod structure 33 and the slider.

[0049] Specifically, the eccentric cross grooves of the slider are respectively penetrated by a horizontal screw rod structure 34 and a vertical screw rod structure 33. When the vertical screw rod structure 33 rotates, the slider moves up and down; the horizontal movable support 32 is relatively fixed to the horizontal screw rod structure 34. When the horizontal screw rod structure 34 rotates, the horizontal screw rod structure 34 moves along the X direction relative to the slider, driving the horizontal movable support 32 to move along the X direction.

[0050] Specifically, the L-shaped vertical mounting bracket serves as the main body of the drive and measurement mechanism 102 and is bolted to the worktable 11. The vertical mounting bracket 31 and the horizontal movable support 32 are connected by a slider. The slider has a pair of mutually perpendicular, eccentric cross slots that connect to a set of horizontal and vertical lead screw mechanisms, respectively. Turning the handwheel at the end of either the horizontal or vertical lead screw aligns the push rod 38 in the drive and measurement mechanism 102 with the axial direction of the piston.

[0051] The piston sliding resistance testing device of the present application has an L-shaped support 21 that is slidably connected to the inverted guide rail 12 along the Y direction, and a horizontally movable support 32 slides along the X and Z directions relative to the vertical mounting bracket 31 through a horizontal screw structure 34, a vertical screw structure 33 and a slider. The combination realizes flexible adjustment in the X, Y and Z directions, so that the push rod 38 is aligned with the piston axis, providing a basis for simulating the actual piston return and effectively preventing eccentric wear.

[0052] like Figure 5 and Figure 6As shown, in one embodiment, the push rod 38 and the force sensor 36 are connected via a first sleeve 39 of a semi-enclosed structure, and the driving screw 42 and the force sensor 36 are connected via a second sleeve 40 of a semi-enclosed structure.

[0053] Specifically, the force sensor 36 has a horizontally lying S-shaped structure.

[0054] Specifically, the connection between the force sensor 36 and the push rod 38 is designed as a slidable semi-enclosed sleeve structure. This innovative structural design has the following advantages: The innovative structure used to connect the push rod 38 and the force sensor 36 is connected by a semi-enclosed sleeve. The sleeve is cylindrical in shape, with a hollow structure in the middle and two sets of notches of different sizes on the outside. The connector of the push rod 38 and the force sensor 36 can be quickly placed into it. At the same time, it retains a certain movable gap during connection, allowing the push rod 38 to automatically contact the sleeve and the force sensor 36 during movement. This can eliminate angular and displacement deviations caused by improper assembly and avoid the impact of the force on the lead screw on the force sensor when the servo motor is just started. The force sensor 36 is connected to the horizontal screw structure 42 and the push rod 38 respectively through two sleeves. The length and diameter of the push rod 38 can be replaced according to the distance between the test sample and the drive mechanism and the size of the piston 57, and it has strong versatility. Compared with the problem of hard connection of the force sensor 36 to the horizontal screw structure 42 and the push rod 38, which may cause the problem of blocking, the present application is more conducive to test measurement.

[0055] Furthermore, the first sleeve 39 and the second sleeve 40 are designed as a special semi-enclosed structure that can slide, and the specific implementation process is as follows: Figure 6 As shown, the force sensor 36 is nested within the central recess of the semi-enclosed first and second sleeves 39, 40, via a first stepped cylindrical boss 36a and a second boss 36b connected at both ends. When the force sensor 36 needs to be replaced or measured, it can be quickly removed from the first and second sleeves 39, 40 without disassembly. A clearance is provided between the force sensor 36 and the first and second sleeves 39, 40. During testing, this clearance is automatically eliminated when force is transmitted, preventing measurement errors caused by impact or mechanical jamming of the force sensor 36.

[0056] Specifically, the first sleeve 39 is connected to the top rod 38 through a thread, and the second sleeve 40 is connected to the driving screw 42 through upper and lower fastening screws 44 (see Figure 6 ).

[0057] like Figure 4 As shown, in one embodiment, the horizontal movable support 32 is provided with an upward opening slot, and the driving screw 42, the force sensor 36, and the displacement sensor 37 are all accommodated in the opening slot. An L bracket 35 is also provided in the opening slot.

[0058] Displacement sensor 37 is mounted at the bottom of the open slot in horizontally movable support 32. The vertical plate of L-shaped bracket 35 is linked to drive screw 42. During the movement of drive screw 42, the horizontal plate of L-shaped bracket 35 drives the contact points on displacement sensor 37 to move. Specifically, the horizontal plate of L-shaped bracket 35 is fixed to displacement sensor 37. Displacement sensor 37 is set to an initial position, at which the displacement value is zero. When displacement sensor 37 moves relative to horizontally movable support 32, it records the displacement value, i.e., the position of ejector 38.

[0059] like Figure 4 As shown, in one embodiment, two position switches 43 are respectively installed at both sides of the upper edge X of the opening slot of the horizontal movable support 32, and the two position switches 43 are used for safety protection during operation.

[0060] When the push rod 38 reaches the limit position, that is, the force sensor itself or the auxiliary structure contacts the position switch 43, the position switch 43 will activate the protection alarm mechanism to prompt the experimenter to adjust the position.

[0061] Specifically, the auxiliary structure primarily consists of two additional sensing plates: one perpendicular to the drive screw 42 and the other perpendicular to the ejector rod 38. Position switches are mounted on the upper side of the horizontal drive support, one on each side, to safely limit the movement of the ejector rod 38 during testing. When the distance between the sensing plate and the proximity switch reaches a set value, a safety mechanism is activated, causing the drive mechanism to come to an emergency stop and the screw to stop moving, preventing damage to the equipment or sample.

[0062] like Figure 4 As shown, in one embodiment, the driving and measuring mechanism 102 further includes a servo motor 41, which is fixed to the side end of the horizontal movable support 32. The controller drives the driving screw 42 and the force sensor 36 forward through the servo motor 41, and links the displacement sensor 37 to move through the L bracket 35.

[0063] The servo motor 41 of the present application can well control the uniform motion when pushing the piston 57 to move, thereby preventing sudden changes in resistance caused by acceleration or deceleration during the measurement process.

[0064] During the actual working process, the controller selects the corresponding instruction. When it needs to return to the initial position after completing a pushing movement, the servo motor 41 drives the driving screw 42 to retreat. Since the two sleeves adopt a semi-closed structure, the force sensor 36 and the displacement sensor 37 are returned to the initial position through the air supply mechanism 103, and the next cycle test is restarted.

[0065] Specifically, the servo motor 41 is fixed to the side end of the horizontal moving support 32 by bolts. During the test, the servo motor 41 drives the driving screw 42 to push the force and displacement sensor to move along the X direction and control its running speed.

[0066] like Figure 2 and Figure 3 As shown, in one embodiment, the sample clamping mechanism 101 further includes a transition plate 22 and two slide plates 23 , and the transition plate 22 is installed on the top of the L-shaped support 21 .

[0067] The bottom of the caliper body 56 is rotatably connected to the center of the transition plate 22 .

[0068] The transition plate 22 is provided with two protruding limit bolts, each slide plate 23 has a long waist round hole, the top ends of the two slide plates 23 are fixed to the caliper body 56, and the two limit bolts are respectively passed through the long waist round holes of the two slide plates 23; the caliper body 56 adjusts the vertical angle of the caliper body 56 relative to the transition plate 22 according to the actual vehicle angle known in advance.

[0069] Specifically, the sample clamping mechanism 101 comprises an L-shaped support 21, a transition plate 22, and two slides 23. The L-shaped support 21 is bolted to the test bench's workbench, while the transition plate 22 is connected to the L-shaped support 21 via a hole-and-shaft fit. A long, waist-shaped slot is defined between the two slides 23. One end of the slide 23 is bolted to the transition plate's mounting hole, while the top end is used to secure the caliper body 56.

[0070] The piston sliding resistance test device of the present application can conveniently adjust the assembly position of the test caliper to simulate the installation angle of the actual vehicle by adjusting the installation angle and position of the two slide plates (see Figure 3 The ß angle in the figure is consistent with that of the actual vehicle).

[0071] Specifically, the car's disc brake is the actuator of the car's braking system. When the car is driving, the movement of the piston in the brake caliper assembly drives the brake friction pad to clamp the brake disc to achieve the car's braking function. When the car needs to release the brake state, the piston in the brake caliper assembly should automatically retract under the action of the return force (corresponding to Figure 2 The friction plate disengages from the brake disc to release the brake.

[0072] The piston sliding resistance testing device of the present application implements an innovative design in the device, which can realize convenient, accurate and rapid testing of test samples.

[0073] The working principle of the piston sliding resistance test device of this application is as follows: Before the test begins, first press the sample of the brake caliper assembly to be tested Figure 2Fixed on the vertical bracket (the specific implementation is similar to the clamping of the actual vehicle, which will not be described in detail in this application), the piston axis is parallel to the base of the test platform, and the assembly angle of the caliper body on the test platform (i.e. Figure 3 The angle ß in the figure is the same as that in the real vehicle. Adjust the initial position of the push rod that drives the measuring mechanism so that the axis of the push rod coincides with the axis of the piston. The piston sliding resistance tester features flexible adjustments for both the specimen clamping position and the vertical and horizontal positioning of the ejector pin. The length of ejector pin 38 can also be easily adjusted to accommodate different test specimen sizes. The innovative semi-sleeve connection between ejector pin 38 and force sensor 36 eliminates potential impact, freezing, or pullout.

[0074] The piston sliding resistance test apparatus is equipped with an independent air supply mechanism 103, consisting of an air pump 51, an air reservoir 52, a pressure regulating valve 53, a pressure gauge, and a piping system. Before testing, one end of the air pipe is connected to the brake fluid inlet of the specimen and the other end to the air source. The air pump is turned on to store compressed air in the air reservoir. The pressure regulating valve ensures that the air pressure delivered to the specimen by the piping system remains within the specified value, preventing pressure fluctuations from affecting the test results.

[0075] After the sample is clamped and adjusted, ejector pin 38 is automatically adjusted to its initial position. The air line switch is turned on, and compressed air enters the sample inlet, pushing piston 57 of the brake caliper assembly from its initial position to the position under braking operation. The position of piston 57 under braking operation can be determined by adjusting the ejector pin's initial position using test input. After the piston moves to the braking operation position, the external air supply is turned off, and the ejector pin is moved to a position coaxial with the piston. The ejector pin then pushes forward to simulate the piston's return process.

[0076] Preferably, an air pump, an air cylinder, a pressure regulating valve, a pressure gauge and other devices are arranged in the bottom space of the test bench, which can be connected to the air inlet 59 of the test bench sample through an air pipe to enable the piston to be pushed to the initial position (i.e., the position under the braking working state) before the test begins.

[0077] In a second aspect, the present application discloses a test method based on the above-mentioned piston sliding resistance test device, comprising the following steps: The first step of preparation is to drive the measuring mechanism 102 and the sample clamping mechanism 101 to move relative to each other until the axis of the ejector rod 38 coincides with the axis of the piston 57; The second step of preparation is to adjust the assembly angle of the caliper body in the sample clamping mechanism 101 according to the known assembly angle of the actual vehicle; In the third step of preparation, the air supply mechanism 103 pushes the piston 57 to the initial position (corresponding to the position in the braking working state); To perform the actual pushing operation, the air supply mechanism 103 is closed, and the driving screw 42 drives the push rod 38 through the force sensor 36 to push the piston 57 to slide relative to the caliper body 56 in the positive X direction, simulating the piston return process. The controller generates the force-displacement curve in real time for the first time. The air supply mechanism 103 resets the piston 57 and the push rod 38 pushes the piston 57 repeatedly, and the controller generates the force-displacement curve in real time multiple times.

[0078] The controller automatically identifies and determines the resistance peak value of each curve and whether there is a resistance mutation. When the resistance peak value is less than or equal to the set resistance peak threshold, and the maximum resistance mutation is less than or equal to the set resistance mutation threshold, it means that the brake caliper assembly is qualified. Otherwise, it means that the brake caliper assembly is unqualified, and the location causing the resistance mutation can be quickly found.

[0079] Specifically, after the sample is clamped and adjusted, the air supply mechanism 103 is activated. Air pressure pushes the sample piston to the right to the initial test position (corresponding to the position in the braking state). The servo motor then drives the lead screw at the set speed. Force and displacement sensors in the test apparatus collect real-time force and travel data from the ejector pin and provide feedback to the controller. If the test needs to continue with the next cycle, the drive motor drives the lead screw back to its initial position, and the air supply mechanism 103 pushes the piston back to its initial position. After the command is input, the test will begin again for the next cycle. After the test is completed, the control system automatically generates a force-displacement curve based on the collected data as the specimen piston slides. This curve can be used to clearly see the change in force during the displacement process, whether the resistance is within the limit, and whether there are any abnormal force mutation points.

[0080] The control logic of the present invention is clear. When replacing different test samples, only the test parameters need to be changed while keeping the underlying control strategy basically consistent. The sequence can be automatically generated to complete the corresponding test.

[0081] Regarding the test methods, such as Figure 2 and Figure 3 As shown, in one embodiment, the sample clamping mechanism 101 further includes a transition plate 22 and two slide plates 23 , and the transition plate 22 is installed on the top of the L-shaped support 21 .

[0082] The bottom of the caliper body 56 is rotatably connected to the center of the transition plate 22 .

[0083] The transition plate 22 is provided with two protruding limit bolts, each slide plate 23 has a long waist round hole, the top ends of the two slide plates 23 are fixed to the caliper body 56, and the two limit bolts are respectively passed through the long waist round holes of the two slide plates 23; the caliper body 56 adjusts the vertical angle of the caliper body 56 relative to the transition plate 22 according to the actual vehicle angle known in advance.

[0084] Specifically, the sample clamping mechanism 101 comprises an L-shaped support 21, a transition plate 22, and two slides 23. The L-shaped support 21 is bolted to the test bench's workbench, while the transition plate 22 is connected to the L-shaped support 21 via a hole-and-shaft fit. A long, waist-shaped slot is defined between the two slides 23. One end of the slide 23 is bolted to the transition plate's mounting hole, while the top end is used to secure the caliper body 56.

[0085] The piston sliding resistance test device of the present application can conveniently adjust the assembly position of the test caliper to simulate the installation angle of a real vehicle by adjusting the installation angle and position of the two slide plates.

[0086] Specifically, if Figure 7 As shown, the sample clamping mechanism 101 is first used to clamp the test sample 104 , and the test sample 104 includes a caliper body 56 and a piston 57 .

[0087] The piston 57 of the test sample 104 is adjusted to the initial position (the position after braking).

[0088] The controller issues a control instruction, the servo motor moves, drives the screw rod to move the push rod, and the push rod pushes the piston 57 of the test sample 104 to move; at the same time, the controller collects and calculates data through the force sensor and displacement sensor.

[0089] The air supply mechanism 103 is used to supply air to the piston 57 and push the piston 57 to slide relative to the caliper body 56 in the negative X direction to reset.

[0090] In the description of this application, it should be noted that the terms "upper" and "lower" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0091] It should be noted that, in this application, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0092] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. A brake caliper assembly piston sliding resistance test device, characterized in that: Include: A test bench (100) comprising a workbench plate (11); A sample clamping mechanism (101) for clamping the caliper body (56) and the piston (57); A driving and measuring mechanism (102) comprises a push rod (38), a force sensor (36) and a driving screw (42) which are arranged in sequence on the same axis; the driving and measuring mechanism and the sample clamping mechanism are both perpendicular to the workbench (11), and the two can move relative to each other until the axis of the push rod (38) coincides with the axis of the piston (57); the driving screw (42) drives the push rod (38) through the force sensor (36) to push the piston (57) to slide along the positive X direction relative to the caliper body (56); the driving screw (42) is provided with a displacement sensor (37) to record its displacement value; An air supply mechanism (103) is used to supply air to the piston (57) and push the piston (57) to slide relative to the caliper body (56) in the negative X direction and return to an initial position; The controller has signals connected to the displacement sensor (37) and the force sensor (36). The controller generates a force-displacement curve in real time each time the push rod (38) pushes the piston (57).

2. A brake caliper assembly piston sliding resistance test device according to claim 1, characterized in that: The test bench further includes an air supply mechanism (103), which includes an air pump (51), an air reservoir (52), a pressure regulating valve (53) and an air pressure gauge (54) connected in sequence through an air pipe, and the air pressure gauge (54) is connected to the cavity between the bottom wall of the piston (57) and the wheel cylinder of the caliper body (56) through a pipeline.

3. The piston sliding resistance testing device for a brake caliper assembly according to claim 1, characterized in that: An undercut guide rail (12) is provided on the upper surface of the workbench (11), and the sample clamping mechanism (101) comprises an L-shaped support (21) located at the bottom, wherein the L-shaped support (21) is slidably connected to the undercut guide rail (12) along the Y direction.

4. The piston sliding resistance testing device for a brake caliper assembly according to claim 1, wherein: The driving and measuring mechanism (102) further comprises a vertical mounting bracket (31) and a horizontal movable support (32); the vertical mounting bracket (31) is provided with a vertical screw rod structure (33), and the horizontal movable support (32) is provided with a horizontal screw rod structure (34); The vertical mounting bracket (31) is vertically fixed to the workbench (11); the push rod (38), force sensor (36), drive screw (42) and displacement sensor (37) are all arranged on the horizontal movable support (32); The horizontal screw rod structure (34) and the vertical screw rod structure (33) are vertically staggered and connected via a slider having a cross groove on different sides, and the horizontal movable support (32) slides relative to the vertical mounting bracket (31) along the X direction and the Z direction via the horizontal screw rod structure (34), the vertical screw rod structure (33) and the slider.

5. The piston sliding resistance testing device for a brake caliper assembly according to claim 1, characterized in that: The push rod (38) and the force sensor (36) are connected via a first sleeve (39) of a semi-enclosed structure, and the driving screw (42) and the force sensor (36) are connected via a second sleeve (40) of a semi-enclosed structure.

6. A brake caliper assembly piston sliding resistance test device according to claim 4, characterized in that: The horizontal movable support (32) is provided with an upward opening slot, and the driving screw (42), the force sensor (36), and the displacement sensor (37) are all accommodated and arranged in the opening slot; an L bracket (35) is also provided in the opening slot; the displacement sensor (37) is installed at the bottom of the opening slot of the horizontal movable support (32), and the vertical plate of the L bracket (35) is linked with the driving screw (42). During the movement of the driving screw (42), the horizontal plate of the L bracket (35) drives the contact on the displacement sensor (37) to move.

7. A brake caliper assembly piston sliding resistance test device according to claim 6, characterized in that: Two position switches (43) are respectively installed at both sides of the upper edge of the opening slot of the horizontal movable support (32) in the X direction; when the push rod (38) moves to the limit position, the position switch (43) starts the protection alarm.

8. The piston sliding resistance testing device for a brake caliper assembly according to claim 6, characterized in that: The driving and measuring mechanism (102) further includes a servo motor (41), which is fixed to the side end of the horizontal movable support (32). The controller drives the driving screw (42) and the force sensor (36) forward through the servo motor (41), and moves the displacement sensor (37) in a linked manner through the L bracket (35).

9. The brake caliper assembly piston sliding resistance test device according to claim 3, characterized in that: The sample clamping mechanism (101) further comprises a transition plate (22) and two slide plates (23), wherein the transition plate (22) is mounted on the top of the L-shaped support (21); the bottom of the caliper body (56) is rotatably connected to the center of the transition plate (22); The transition plate (22) is provided with two outwardly extending limiting bolts, each slide plate (23) has a long waist circular hole, the top ends of the two slide plates (23) are fixed to the caliper body (56), and the two limiting bolts are respectively passed through the long waist circular holes of the two slide plates (23); the caliper body (56) adjusts its own vertical angle relative to the transition plate (22) according to the actual vehicle angle known in advance.

10. A test method based on the piston sliding resistance test device according to any one of claims 1 to 9, comprising the following steps: The driving and measuring mechanism (102) and the sample clamping mechanism (101) are relatively moved until the axis of the ejector rod (38) coincides with the axis of the piston (57); Adjusting the assembly angle of the caliper body in the sample clamping mechanism (101) according to a known actual vehicle assembly angle; The air supply mechanism (103) pushes the piston (57) to an initial position; The air supply mechanism (103) is closed, and the driving screw (42) drives the push rod (38) through the force sensor (36) to push the piston (57) relative to the caliper body (56) along the positive X direction to simulate the piston return process. The controller generates a force-displacement curve in real time for the first time; The air supply mechanism (103) resets the piston (57) and the push rod (38) pushes the piston (57) repeatedly, and the controller generates a force-displacement curve in real time multiple times.

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