A method of controlling a brake caliper

Abstract

The application discloses a kind of control methods of brake caliper, including steps: S1, control brake caliper motor operation, piston is retreated with inner brake shoe, brake caliper body drives outer brake shoe to move, brake caliper body drives outer brake shoe to generate displacement;S2, control motor deceleration, piston pushes brake caliper force less than the friction between guide pin and bracket guide pin hole, brake caliper body and outer brake shoe position remain unmoved, motor deceleration to zero;S3, control motor reverse to small acceleration and deceleration operation, make piston small acceleration advance, make inner brake shoe reset to the appropriate gap position with brake disc;S4, make the gap between outer brake shoe and brake disc reach set value.The control method of brake caliper of the application can realize brake caliper body when braking release, without the help of return spring, let inner and outer brake shoe quickly retreat to set gap, and brake is dragged to zero or very excellent level.

Description

Technical Field

[0001] This invention belongs to the field of braking system technology, specifically, it relates to a control method for a brake caliper. Background Technology

[0002] When a vehicle releases the brakes, the sliding resistance between the brake caliper guide pin and the bracket guide pin hole, known as caliper slip resistance, prevents the brake caliper from fully resetting after braking. This results in the brake pads not completely disengaging from the brake disc, causing a dragging phenomenon. The reason is that current technology controls the gap between the inner brake pad and the brake disc by controlling a motor to retract a piston a certain distance. The piston and inner brake pad are fixed together, and the motor-driven piston retraction allows the inner brake pad to directly separate from the brake disc to the set gap position. However, the resistance (sliding resistance) between the brake caliper guide pin and the bracket guide pin hole means that while the piston is retracting the inner brake pad, the caliper pawl may not be able to retract the outer brake pad to the set gap position, potentially resulting in the outer brake pad not completely disengaging from the brake disc. Summary of the Invention

[0003] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention provides a control method for a brake caliper, the purpose of which is to enable the caliper body to overcome the slip resistance of the caliper body and drive the brake pads to return to their original position quickly, thereby avoiding the occurrence of dragging phenomenon.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is: a brake caliper control method, comprising the following steps:

[0005] S1. Control the motor of the brake caliper to make the piston retract with the first acceleration. The force of the piston pulling the brake caliper body overcomes the resistance between the guide pin of the caliper body and the guide pin hole on the bracket. The brake caliper body drives the outer brake pad to move. The brake caliper body drives the outer brake pad to generate displacement a.

[0006] S2. Control the motor to decelerate, so that the piston retracts with the second acceleration. The force of the piston pushing the brake caliper is less than the frictional force between the guide pin and the guide pin hole of the bracket. The position of the brake caliper and the outer brake pad remains unchanged, and the motor decelerates to zero.

[0007] S3. Control the motor to run in reverse, so that the piston moves forward with the third acceleration, so that the inner brake pad returns to the appropriate gap position with the brake disc. At this time, due to the friction between the guide pin and the guide pin hole of the bracket, the gap a between the outer brake pad and the brake disc remains unchanged after step S1.

[0008] S4. Determine whether the gap between the outer brake pad and the brake disc has reached the set value s; if the gap between the outer brake pad and the brake disc has not reached the set value s, repeat steps S1 to S3 again until the gap between the outer brake pad and the brake disc reaches the set value s.

[0009] The first acceleration is greater than the second acceleration or the third acceleration.

[0010] The piston is fixed to the inner brake pad.

[0011] The outer brake pad is fixedly connected to the claw of the brake caliper.

[0012] The brake caliper body is provided with a motion conversion mechanism, which includes a translation component and a rotation component, and the piston is integrated with the translation component.

[0013] A rotating component is provided inside the brake caliper body, and the rotating component and the piston form a helical transmission pair.

[0014] Each execution of steps S1 to S3 constitutes one cycle. The number of cycles required to complete the inner and outer brake pads and brake disc to reach the set gap value is n, and the number of cycles n is greater than s / a.

[0015] The set value s = 0.1 mm.

[0016] In step S1, under the same working conditions and the same standard operation, the piston retracts by the same amount of displacement each time.

[0017] To avoid dragging, the brake calipers installed on the four wheel ends of the vehicle are executed in a synchronous or stepwise manner according to steps S1 to S4. This invention recommends that they be executed in the following order: wheel end 1 brake caliper → wheel end 2 brake caliper → wheel end 3 brake caliper → wheel end 4 brake caliper.

[0018] The brake caliper control method of the present invention enables the brake caliper body to quickly retract the inner and outer brake pads to the set gap without the aid of a return spring when the brake is released, thereby dragging the brake to zero or a very good level. Attached Figure Description

[0019] This manual includes the following figures, which illustrate the following:

[0020] Figure 1 This is a schematic diagram of the brake caliper in the braking state, with the gap between the inner and outer brake pads and the brake disc being 0.

[0021] Figure 2 This is a schematic diagram showing the inner brake pad disengaging and the outer brake pad dragging after the brake caliper is released according to existing technology.

[0022] Figure 3This is a schematic diagram showing the state where the brake caliper is in the execution of step S1, the inner brake pad retracts, and the outer brake pad and brake disc create a gap a.

[0023] Figure 4 This is a schematic diagram showing the state where the gap between the inner and outer brake pads and the brake disc reaches a set value after the brake caliper cyclically executes the control method described above.

[0024] The following are labeled in the diagram: 1. Actuator; 2. Brake caliper; 3. Output shaft; 4. Piston; 5. Inner brake pad; 6. Brake disc; 7. Outer brake pad. Detailed Implementation

[0025] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, in order to help those skilled in the art to have a more complete, accurate and in-depth understanding of the concept and technical solutions of the present invention, and to facilitate its implementation.

[0026] Example 1

[0027] like Figures 1 to 4 As shown, this embodiment provides a brake caliper control method, including the following steps:

[0028] S1. Control the motor of the brake caliper to operate, so that the piston 4 retracts with the first acceleration. The force of the piston 4 pulling the brake caliper body 2 overcomes the resistance between the guide pin of the caliper body and the guide pin hole on the bracket. The brake caliper body 2 drives the outer brake pad 7 to move, and the brake caliper body 2 drives the outer brake pad 7 to generate displacement a.

[0029] S2. Control the motor to decelerate, so that the piston 4 retracts with the second acceleration. The force of the piston 4 pushing the brake caliper 2 is less than the frictional force between the guide pin and the guide pin hole of the bracket. The positions of the brake caliper 2 and the outer brake pad 7 remain unchanged, and the motor decelerates to zero.

[0030] S3. Control the motor to run in reverse, so that the piston 4 moves forward with the third acceleration, so that the inner brake pad 5 returns to the appropriate gap position with the brake disc 6. At this time, due to the friction between the guide pin and the guide pin hole of the bracket, the gap a between the outer brake pad 7 and the brake disc 6 remains unchanged after step S1. That is, the gap a between the outer brake pad 7 and the brake disc 6 is the same as the displacement a generated by the brake caliper 2 driving the outer brake pad 7 in step S1.

[0031] S4. Determine whether the gap between the outer brake pad 7 and the brake disc 6 reaches the set value s; if the gap between the outer brake pad and the brake disc does not reach the set value s, repeat steps S1 to S3 until the gap between the outer brake pad and the brake disc reaches the set value s.

[0032] Specifically, such as Figures 1 to 3As shown, the brake caliper includes an actuator 1, a bracket, a brake caliper body 2, an inner brake pad 5, an outer brake pad 7, and a motion conversion mechanism. The actuator 1 includes a motor and a transmission mechanism. The brake caliper body 2 is a floating caliper structure with a cylinder bore and a hook structure. The inner brake pad 5, brake disc 6, and outer brake pad 7 are sequentially installed within the hook structure. The structure of the brake caliper body 2, the motor, and the transmission mechanism is as is known to those skilled in the art. The gear at the power input end of the transmission mechanism is connected to the motor, and the gear at the power output end of the transmission mechanism is connected to the motion conversion mechanism. The motion conversion mechanism includes a rotating component and a translating component. The motion conversion mechanism is a ball screw pair, the rotating component is a screw shaft, and the translating component is a piston 4. The inner wall of the piston 4 is provided with a threaded raceway. The translating component and the rotating component form a ball screw pair. The brake caliper body 2 is connected to the bracket by a guide pin. The bracket is provided with a guide pin hole through which the caliper body guide pin passes. The caliper body guide pin contacts the inner wall surface of the guide pin hole, and there is sliding resistance between the caliper body guide pin and the guide pin hole.

[0033] In this embodiment, the first acceleration is greater than the second acceleration or the third acceleration.

[0034] In this embodiment, as Figures 1 to 3 As shown, piston 4 and inner brake pad 5 are fixedly connected as one unit. Piston 4 and inner brake pad 5 move synchronously. The end face of piston 4 is fixedly connected to inner brake pad 5 as one unit, so that inner brake pad 5 can be directly driven to exit when piston 4 exits quickly.

[0035] In this embodiment, as Figures 1 to 3 As shown, the outer brake pad 7 is fixedly connected to the claw of the brake caliper 2, and the outer brake pad 7 and the brake caliper 2 move synchronously.

[0036] like Figure 1 As shown, when the brake caliper is in the braking state, the gap between the inner brake pad 5 and the outer brake pad 7 and the brake disc 6 is zero.

[0037] In step S1 above, the motor of actuator 1 is a brushless motor. The motor generates sufficient torque to quickly pull piston 4 back with high acceleration and generate sufficient acceleration.

[0038] In step S1 above, after the motor starts running, the piston 4 can be retracted. The piston 4 drives the inner brake pad 5 to move synchronously, so that the brake caliper 2 overcomes the sliding resistance between the guide pin and the guide pin hole. The brake caliper 2 drives the outer brake pad 7 to move synchronously. The direction of movement of the brake caliper 2 is opposite to the direction of movement of the piston 4. The brake caliper 2 drives the outer brake pad 7 to generate displacement a, so that the outer brake pad 7 disengages from the brake disc 6.

[0039] Let the mass of the first assembly be m1 and the mass of the second assembly be m2. In step S1 above, when the first assembly rapidly retracts with acceleration a1, let the acceleration of the second assembly be a2. According to the law of conservation of momentum, m1*a1 = -m2*a2. Simultaneously, while the first assembly generates a velocity v1 due to acceleration a1, the second assembly will necessarily have a velocity v2 in the opposite direction due to acceleration a2. The first and second assemblies move in opposite directions. The first assembly includes a piston 4 and an inner brake pad 5. The mass m1 of the first assembly is the sum of the masses of the piston 4 and the inner brake pad 5. The mass m2 of the second assembly is the total mass of all components of the brake caliper except for the first assembly. The second assembly includes the brake caliper body 2, the outer brake pad 7, the caliper guide pin, and the actuator 1, among other components.

[0040] Initially, both the first and second assemblies are at rest. According to the momentum theorem: m1v1 + m2v2 = 0. Therefore, initially, the velocities of both assemblies are zero, i.e., v1 = 0 and v2 = 0.

[0041] In step S1 above, when piston 4 retracts with a first acceleration (a large acceleration):

[0042] Using the momentum theorem or Newton's third law: m1*a1*t+m2*a2*t=0 or F1+F2=0 (F1 is the force of the second assembly pulling the first assembly; F2 is the force of the first assembly pulling the second assembly), a1 is the acceleration of the first assembly, a2 is the acceleration of the second assembly, and t is time;

[0043] The force F1 is converted from the motor torque into the force that pulls the piston 4. If mass and friction are not considered, the maximum force when the piston 4 retracts is the same as the maximum force when it is clamped, which is 60 to 65 kN.

[0044] F2 = -F1. Under the condition of generating force F2, the brake caliper 2 can be pulled to move, causing the brake caliper 2 and the outer brake pad 7 to have a displacement a.

[0045] Although the mass m2 of the second assembly is greater than the mass m1 of the first assembly, and the movement of the brake caliper 2 is subject to certain resistance due to the existence of the caliper body sliding resistance, theoretically, as long as the mass m1 of the first assembly is large enough and the retraction speed v1 of the first assembly is large enough, the brake caliper 2 will inevitably be able to move in the opposite direction and generate displacement a, but the generated displacement is insufficient to meet the requirements for reducing drag.

[0046] In step S2 above, the motor is controlled to decelerate, causing the piston 4 to retract with a second acceleration. The force of the piston pushing the brake caliper 2 is less than the frictional force between the guide pin and the guide pin hole on the bracket. The positions of the brake caliper 2 and the outer brake pad 7 remain unchanged until the motor decelerates to zero.

[0047] In step S3 above, after piston 4 decelerates to zero, the control motor rotates slowly in the opposite direction, causing piston 4 to move forward with a third acceleration (a small acceleration), so that the inner brake pad 5 returns to the appropriate gap position with the brake disc 6. At this time, due to the friction between the guide pin and the guide pin hole on the bracket, the gap a between the outer brake pad 7 and the brake disc 6 remains unchanged after step S1, that is, the brake caliper 2 does not move, and the brake caliper 2 and the outer brake pad 7 remain in the same position.

[0048] Each execution of steps S1 to S3 constitutes one cycle. The number of cycles required to complete steps S1 to S3 to achieve the set gap value between the inner and outer brake pads 5 and 7 and the brake disc 6 is n, where n is greater than s / a. a represents the displacement of the outer brake pad 7 caused by the brake caliper 2 after each cycle. That is, after each cycle of step S1, the displacement of the outer brake pad 7 caused by the brake caliper 2 is the same, and the displacement of the piston 4 during each retraction is also the same.

[0049] In this embodiment, in step S4 above, the set value s = 0.1 mm.

[0050] For vehicles with four wheels, each wheel is equipped with a brake caliper. The brake calipers at all four wheel ends are executed synchronously or in stages via steps S1 to S4 to avoid dragging. This invention recommends executing the brake calipers in the following order: wheel end 1 brake caliper → wheel end 2 brake caliper → wheel end 3 brake caliper → wheel end 4 brake caliper. Wheel end 1 and wheel end 2 are the brake calipers installed on the two front wheels of the vehicle, while wheel end 3 and wheel end 4 are the brake calipers installed on the two rear wheels of the vehicle. During vehicle braking, the brake calipers at wheel end 1 are controlled first according to the control method of this embodiment, then the brake calipers at wheel end 2 are controlled according to the control method of this embodiment, then the brake calipers at wheel end 3 are controlled according to the control method of this embodiment, and finally the brake calipers at wheel end 4 are controlled according to the control method of this embodiment, thus avoiding dragging of the four wheel end brake calipers.

[0051] Example 2

[0052] In this embodiment, the motion conversion mechanism includes a translation component and a rotating component. The rotating component is a lead screw shaft, and the translation component is a nut. The inner wall of the nut is provided with a threaded raceway. The translation component and the rotating component form a ball screw pair, and the piston 4 is integrated with the translation component.

[0053] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution; or the direct application of the inventive concept and technical solution to other situations without modification, are all within the protection scope of the present invention.

Claims

1. A method for controlling a brake caliper, characterized in that, Including the following steps: S1. Control the motor of the brake caliper to make the piston retract with the first acceleration. The force of the piston pulling the brake caliper body overcomes the resistance between the guide pin of the caliper body and the guide pin hole on the bracket. The brake caliper body drives the outer brake pad to move. The brake caliper body drives the outer brake pad to generate displacement a. S2. Control the motor to decelerate, so that the piston retracts with the second acceleration. The force of the piston pushing the brake caliper is less than the friction between the guide pin and the guide pin hole of the bracket. The position of the brake caliper and the outer brake pad remains unchanged, and the motor decelerates to zero. S3. Control the motor to run in reverse, so that the piston moves forward with the third acceleration, so that the inner brake pad returns to the appropriate gap position with the brake disc. At this time, due to the friction between the guide pin and the guide pin hole of the bracket, the gap a between the outer brake pad and the brake disc remains unchanged after step S1. S4. Determine whether the gap between the outer brake pad and the brake disc has reached the set value s; if the gap between the outer brake pad and the brake disc has not reached the set value s, repeat steps S1 to S3 until the gap between the outer brake pad and the brake disc reaches the set value s.

2. The brake caliper control method according to claim 1, characterized in that, The first acceleration is greater than the second acceleration or the third acceleration.

3. The brake caliper control method according to claim 1, characterized in that, The piston is fixed to the inner brake pad.

4. The brake caliper control method according to claim 1, characterized in that, The outer brake pad is fixedly connected to the claw of the brake caliper.

5. The brake caliper control method according to any one of claims 1 to 4, characterized in that, The brake caliper body is provided with a motion conversion mechanism, which includes a translation component and a rotation component, and the piston is integrated with the translation component.

6. The brake caliper control method according to any one of claims 1 to 4, characterized in that, A rotating component is provided inside the brake caliper body, and the rotating component and the piston form a helical transmission pair.

7. The brake caliper control method according to any one of claims 1 to 4, characterized in that, Each execution of steps S1 to S3 constitutes one cycle. The number of cycles required to complete the inner and outer brake pads and brake disc to reach the set gap value is n, and the number of cycles n is greater than s / a.

8. The brake caliper control method according to claim 7, characterized in that, The set value s = 0.1 mm.

9. The brake caliper control method according to any one of claims 1 to 4, characterized in that, In step S1, under the same working conditions and the same standard operation, the piston retracts by the same amount of displacement each time.

10. The brake caliper control method according to any one of claims 1 to 4, characterized in that, The brake calipers installed at the four wheel ends of the vehicle execute steps S1 to S4 synchronously or in stages to avoid dragging.

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