Electronic mechanical brake assembly

Abstract

The utility model discloses an electronic mechanical brake assembly, which belongs to the field of automobile braking, and comprises an EMB actuator and a caliper assembly connected with the output end of the EMB actuator, the caliper assembly comprises a support, a caliper body arranged on the support through a guide pin, a lead screw assembly, a friction plate assembly and a clamping force sensing assembly, the clamping force sensing assembly is a strain unit arranged at the bottom of the outer side of the caliper body or on the annular face side, and the strain unit is composed of at least one full-bridge strain gauge. According to the electronic mechanical brake assembly, the external full-bridge strain gauge is used for replacing a built-in force sensor, the overall axial size can be reduced, the overall height is reduced by more than 5 mm, and therefore the requirements of more vehicle types are met.

Description

Technical Field

[0001] This utility model relates to the field of automotive braking technology, and in particular to an electromechanical brake assembly. Background Technology

[0002] During the operation of the electromechanical brake (EMB), the driver presses the brake pedal, sending a braking signal. The vehicle's electronic control unit drives the EMB motor to rotate based on this signal. The motor then reduces speed and increases torque through a gearbox. The reduction mechanism is connected to a lead screw, which converts the rotation into linear motion, pushing the lead screw piston forward. The lead screw piston pushes the friction pads against the brake disc, thereby clamping the brake disc and achieving a deceleration effect until the vehicle stops.

[0003] During this process, the required clamping force varies depending on the operating conditions. The clamping force of the electromechanical brake (EMB) needs to be fed back to the vehicle's electronic control unit (ECU) in real time to match the clamping force issued by the ECU. If the required clamping force is not reached, the ECU continues to drive the EMB motor forward, further increasing the clamping force until the clamping force requirement issued by the ECU is met.

[0004] To address these requirements, current electromechanical brakes (EMBs) typically incorporate a force sensor within the caliper cylinder for real-time monitoring of the clamping force. The sensor is generally located at the end of the leadscrew and at the bottom ring seat within the caliper cylinder. However, due to the harsh working environment within the caliper cylinder, the force sensor is prone to various failures during prolonged use. Furthermore, the force sensor exhibits hysteresis during operation, affecting measurement accuracy. Utility Model Content

[0005] The purpose of this invention is to provide an electromechanical brake assembly to solve the above-mentioned technical problems.

[0006] To achieve the above objectives, this utility model provides an electromechanical brake assembly, including an EMB actuator and a caliper assembly connected to the output end of the EMB actuator. The caliper assembly includes a bracket, a caliper body mounted on the bracket via a guide pin, a lead screw assembly, a friction plate assembly, and a clamping force sensing assembly. The clamping force sensing assembly is a strain unit located on the bottom or toroidal side of the outer side of the caliper body, and the strain unit consists of at least one full-bridge strain gauge.

[0007] Preferably, the EMB actuator includes a housing, an EMB control board integrated inside the housing, an EMB drive motor electrically connected to the EMB control board, and a gear reduction mechanism connected to the output end of the EMB drive motor. The output end of the gear reduction mechanism is connected to the caliper assembly via an output shaft spline and a lead screw assembly.

[0008] Preferably, the lead screw assembly is a ball screw structure, which includes a lead screw shaft that extends out of the caliper body and is splined to the output shaft, a lead screw that is fixedly connected to one end of the lead screw shaft that extends into the caliper body, and a lead screw nut piston that is set on the outside of the lead screw by balls.

[0009] The friction pad assembly includes an inner friction pad assembly and an outer friction pad assembly that are slidably distributed on brackets on both sides of the brake disc. The inner friction pad assembly is aligned with the lead screw piston, and the outer friction pad assembly is connected to the caliper body via caliper jaws. The caliper body is aligned with the shoulder of the lead screw shaft via bearing washers and thrust bearings in sequence. The caliper body also has a guide hole, one end of which is inserted into the guide hole, and the other end of the guide pin is threaded to the bracket. A sliding clearance is left between the guide hole and the guide pin.

[0010] Preferably, the bracket has a T-slot, and an inner friction plate assembly and an outer friction plate assembly are slidably disposed in the T-slot.

[0011] Preferably, a patch groove is provided on the bottom or circumferential side of the outer side of the caliper body, the full-bridge strain gauge is bonded inside the patch groove, and the full-bridge strain gauge is electrically connected to the EMB control board via a wiring harness.

[0012] Preferably, the housing is provided with connectors, and the EMB control board is electrically connected to the automotive electronic control unit via the connectors.

[0013] Therefore, the beneficial effects of this utility model using the above-mentioned electromechanical brake assembly are as follows:

[0014] 1. Improved reliability: The full-bridge strain gauges are arranged on the outside of the caliper body, and the working environment is better than that of the force sensors inside the traditional caliper, thereby reducing its failure rate;

[0015] 2. Enhanced safety: More than two full-bridge strain gauges can be arranged, and the redundant design can provide backup for each other, reducing the risk of single component failure;

[0016] 3. Compact structure: Eliminating the force sensor inside the caliper reduces the overall height of the EMB, making it easier to arrange flexibly in the limited space at the wheel end of the car; and since there is no need to house the force sensor inside the caliper, the structure is simpler, eliminating the limitation of the sensor's shape on the internal space.

[0017] 4. Optimized measurement accuracy: Avoids the hysteresis of force sensors, improving the real-time performance and accuracy of clamping force feedback;

[0018] 5. Cost reduction: Eliminating expensive force sensors reduces hardware costs and improves the cost-effectiveness of EMB products.

[0019] The technical solution of this utility model will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of an electromechanical brake assembly according to the present invention;

[0021] Figure 2 This is a cross-sectional view of the brake caliper of an electromechanical brake assembly according to this utility model;

[0022] Figure 3 This is a bottom view of the outer side of the caliper body of an electromechanical brake assembly according to the present invention.

[0023] Figure 4 This is a schematic diagram of the bracket structure of the caliper body of an electromechanical brake assembly according to the present invention.

[0024] Figure Labels

[0025] 1. EMB drive motor; 2. Housing; 3. Connector; 4. Caliper body; 5. Guide pin; 6. Bracket; 7. Inner friction plate assembly; 8. Outer friction plate assembly; 9. Caliper jaws; 10. Bearing washer; 11. Lead screw shaft; 12. Lead screw; 13. Nut piston; 14. Thrust bearing; 15. Patch groove; 16. Brake disc; 17. T-slot. Detailed Implementation

[0026] In the description of this utility model, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the utility model product is in use. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0027] The embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0028] like Figures 1-4As shown, an electromechanical brake assembly includes an EMB actuator and a caliper assembly connected to the output end of the EMB actuator. The caliper assembly includes a bracket 6, a caliper body 4 mounted on the bracket 6 via a guide pin 5, a lead screw assembly, a friction plate assembly, and a clamping force sensing assembly. The clamping force sensing assembly is a strain unit located on the bottom or ring side of the outer side of the caliper body 4. The strain unit consists of at least one full-bridge strain gauge.

[0029] The EMB actuator includes a housing 2, an EMB control board integrated inside the housing 2, an EMB drive motor 1 electrically connected to the EMB control board, and a gear reduction mechanism connected to the output end of the EMB drive motor 1. The output end of the gear reduction mechanism is connected to the caliper assembly via an output shaft spline and a lead screw assembly.

[0030] The lead screw assembly is a ball screw structure, which includes a lead screw shaft 11 that extends out of the caliper body 4 and is splined to the output shaft, a lead screw 12 that is fixedly connected to one end of the lead screw shaft 11 that extends into the caliper body 4, and a lead screw nut piston 13 that is set on the outside of the lead screw 12 via balls; the friction plate assembly includes an inner friction plate assembly 7 and an outer friction plate assembly 8 that are slidably distributed on the brackets 6 on both sides of the brake disc 16, wherein the inner friction plate assembly 7 is aligned with the lead screw nut piston 13, and the outer friction plate assembly 8 is connected to the caliper body 4 via the caliper jaws 9. The caliper body 4 is aligned with the shoulder of the lead screw shaft 11 via bearing washers and thrust bearings 14 in sequence. The caliper body 4 is also provided with a guide hole, one end of which is inserted into the guide hole, and the other end of the guide pin 5 is threadedly connected to the bracket 4, and a sliding clearance is left between the guide hole and the guide pin 5.

[0031] The bracket 6 has a T-slot 17, and an inner friction plate assembly 7 and an outer friction plate assembly 8 are slidably disposed in the T-slot 17.

[0032] A patch groove 15 is provided on the bottom or circumferential side of the caliper body 4. The full-bridge strain gauge is bonded inside the patch groove 15, and the full-bridge strain gauge is electrically connected to the EMB control board via a wiring harness. A connector 3 is provided on the housing 2, and the EMB control board is electrically connected to the automotive electronic control unit via the connector 3.

[0033] It should be noted that the above electronic components are all mature products on the market. This embodiment only requires purchasing them and connecting them according to the instruction manual. No modifications have been made to them. Therefore, their circuit connection structure and principle will not be described in detail here.

[0034] Working principle: After receiving the braking command sent by the vehicle's electronic control unit, the EMB control board controls the EMB drive motor 1 to operate. The EMB drive motor 1 drives the output shaft to rotate via the gear reduction mechanism. The output shaft drives the lead screw shaft 11 to rotate, which in turn drives the lead screw 12 to rotate. With the cooperation of the lead screw 12 and the lead screw nut piston 13, the rotation of the lead screw 12 is converted into the movement of the lead screw nut piston 13 along the axial direction of the lead screw 12 until it contacts the inner friction plate assembly 7 and drives the inner friction plate assembly 7 to move synchronously until the braking is reliable. At this time, the EMB drive motor 1 continues to operate, but the lead screw nut piston 13 no longer produces displacement under the restriction of the braking position. Under the interaction of forces, the lead screw 12 and the lead screw shaft 11 move in opposite directions, which in turn drives the caliper body 4 to move in opposite directions via the thrust bearing 14 and the bearing washer 10. The caliper body 4 drives the outer friction plate assembly 8 to move via the caliper jaws 9 until the braking is reliable. At this time, the caliper body 4 deforms under the load. The deformation signal is collected by the full-bridge strain gauge and uploaded to the EMB control board, where it is converted into a clamping force signal.

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and not to limit it. Although the utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solution of this utility model, and these modifications or equivalent substitutions cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of this utility model.

Claims

1. An electromechanical brake assembly, comprising an EMB actuator and a caliper assembly connected to the output end of the EMB actuator, the caliper assembly comprising a bracket, a caliper body mounted on the bracket via a guide pin, a lead screw assembly, a friction pad assembly, and a clamping force sensing assembly, characterized in that: The clamping force sensing component is a strain unit located on the bottom or ring side of the outer side of the caliper body. The strain unit consists of at least one full-bridge strain gauge.

2. The electromechanical brake assembly according to claim 1, characterized in that: The EMB actuator includes a housing and an EMB control board integrated inside the housing, an EMB drive motor electrically connected to the EMB control board, and a gear reduction mechanism connected to the output end of the EMB drive motor. The output end of the gear reduction mechanism is connected to the caliper assembly via an output shaft spline and a lead screw assembly.

3. The electromechanical brake assembly according to claim 2, characterized in that: The lead screw assembly is a ball screw structure, which includes a lead screw shaft that extends out of the caliper body and is splined to the output shaft, a lead screw that is fixedly connected to one end of the lead screw shaft that extends into the caliper body, and a lead screw nut piston that is set on the outside of the lead screw by balls. The friction pad assembly includes an inner friction pad assembly and an outer friction pad assembly that are slidably distributed on brackets on both sides of the brake disc. The inner friction pad assembly is aligned with the lead screw piston, and the outer friction pad assembly is connected to the caliper body via caliper jaws. The caliper body is aligned with the shoulder of the lead screw shaft via bearing washers and thrust bearings in sequence. The caliper body also has a guide hole, one end of which is inserted into the guide hole, and the other end of the guide pin is threaded to the bracket. A sliding clearance is left between the guide hole and the guide pin.

4. The electromechanical brake assembly according to claim 3, characterized in that: The bracket has a T-slot, and an inner friction plate assembly and an outer friction plate assembly are slidably installed in the T-slot.

5. An electromechanical brake assembly according to claim 3, characterized in that: The caliper body has a patch groove on the bottom or circumferential side of its outer side. The full-bridge strain gauge is bonded inside the patch groove and is electrically connected to the EMB control board via a wiring harness.

6. An electromechanical brake assembly according to claim 2, characterized in that: The housing is equipped with connectors, and the EMB control board is electrically connected to the automotive electronic control unit via these connectors.

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