CN-117267279-B - Automobile drum brake and control method thereof

Abstract

The invention discloses an automobile drum brake and a control method thereof, wherein the automobile drum brake comprises a brake bottom plate, a first brake shoe, a second brake shoe, a driving assembly and a resetting assembly, wherein the first brake shoe and the second brake shoe are oppositely arranged on the brake bottom plate along the longitudinal axis of the brake bottom plate, the resetting assembly is arranged between the first brake shoe and the second brake shoe, the driving assembly is symmetrically arranged along the transverse axis of the brake bottom plate, the driving assembly comprises a cam device and a driving motor which are mutually connected, the cam device is provided with a self-locking assembly, and contacts at two ends of the first brake shoe and the second brake shoe are respectively contacted with the cam device. The cam device is controlled to rotate positively and reversely through the common braking of the double motors, the self-locking assembly is matched, the parking locking reliability is improved, temporary emergency braking can be completed through a single motor when one motor fails, the fault tolerance and the safety of the system are improved, the force sensor and the displacement sensor are equipped to collect parameters in the braking process, further, the fault and the abrasion condition are judged, and feedback is timely carried out.

Inventors

• ZHANG HOUZHONG
• QI YIYUN
• XU XING
• SUN XIAOQIANG
• WANG FENG

Assignees

• 江苏大学

Dates

Publication Date

20260512

Application Date

20231019

Claims (4)

1. 1. The utility model provides an automobile drum brake, includes brake bottom plate (1), first brake shoe (2), second brake shoe (3), actuating assembly (4) and return assembly (5), first brake shoe (2) and second brake shoe (3) are installed on brake bottom plate (1) along brake bottom plate (1) longitudinal axis relatively, install return assembly (5) between first brake shoe (2) and second brake shoe (3), actuating assembly (4) are installed along brake bottom plate (1) transverse axis symmetry, actuating assembly (4) include cam device (41) and driving motor (42) that interconnect, be equipped with on cam device (41) auto-lock subassembly (6), the both ends contact of first brake shoe (2) and second brake shoe (3) are contacted with cam device (41) respectively; The cam device (41) comprises a first cam mechanism (411) and a second cam mechanism (412), wherein the first cam mechanism (411) and the second cam mechanism (412) are symmetrically arranged along the transverse axis of the brake bottom plate (1); At least two groups of self-locking assemblies (6) on the first cam mechanism (411) and the second cam mechanism (412) are respectively arranged, and the self-locking assemblies (6) on the first cam mechanism (411) and the second cam mechanism (412) are respectively in central symmetry; The self-locking assembly (6) comprises a protruding portion (61) and a groove portion (62), wherein the groove portion (62) is respectively contacted with two end contacts of the first brake shoe (2) and the second brake shoe (3), and the self-locking assembly is characterized in that: The brake bottom plate (1) is provided with a fixed seat (12), the reset assembly (5) comprises a reset groove (51), a limiting rod (52) and a reset spring (53), one end of the limiting rod (52) is fixedly connected with the first brake shoe (2), the other end of the limiting rod is arranged in the reset groove (51) for sliding, the fixed seat (12) is provided with a force sensor (7), one end of the reset spring (53) is connected with the force sensor (7) arranged on the fixed seat (12), and the other end of the reset spring is connected with the first brake shoe (2); The same reset assembly (5) is arranged between the second brake shoe (3) and the fixed seat (12), and at least two sets of reset assemblies (5) are arranged between the first brake shoe (2) and the second brake shoe (3); A displacement sensor (8) is arranged on the braking bottom plate (1) close to the reset groove (51).
2. 2. The drum brake of a vehicle according to claim 1, wherein the return groove (51) is provided with a widening groove (54) extending in the longitudinal direction at one end near the fixing seat (12).
3. 3. The method for controlling a drum brake of an automobile according to claim 2, wherein the method comprises a service braking condition, a parking lock condition and a failure condition; the specific steps of the service braking working condition, the parking locking working condition and the fault working condition are as follows: When a driver performs service braking, the driving motor (42) drives the first cam mechanism (411) to rotate clockwise, and simultaneously drives the second cam mechanism (412) to rotate anticlockwise, the first cam mechanism (411) and the second cam mechanism (412) respectively push the first brake shoe (2) and the second brake shoe (3) to expand outwards along the horizontal direction, and the first brake shoe and the second brake shoe are contacted with the brake drum to generate braking force for stopping, if the braking force is not generated in time for stopping, the output signal of the driving motor (42) is required to be adjusted in time to generate braking force for stopping, and the displacement sensor (8) and the force sensor (7) record the displacement of the limiting rod (52) and the tension of the reset spring (53) in real time; When a driver performs parking locking, the driving motor (42) drives the first cam mechanism (411) and the second cam mechanism (412) to rotate anticlockwise and clockwise respectively, so that contacts at two ends of the first brake shoe (2) and the second brake shoe (3) are respectively contacted with the groove part (62), meanwhile, the first cam mechanism (411) and the second cam mechanism (412) respectively push the first brake shoe (2) and the second brake shoe (3) to expand outwards along the horizontal direction and contact with the brake drum, braking force is generated, and if braking force is not generated in time, output signals of the driving motor (42) are required to be adjusted in time to generate braking force for parking, and the displacement sensor (8) and the force sensor (7) record displacement of the limiting rod (52) and tension of the reset spring (53) in real time; And under the fault working condition, when the second cam mechanism (412) fails, a single motor is adopted for braking, and at the moment, the first cam mechanism (411) is driven by the driving motor (42) to rotate clockwise, so that the first brake shoe (2) and the second brake shoe (3) are pushed to expand outwards to contact with the brake drum, braking force is generated to stop, and a fault signal is sent to a driver.
4. 4. The method for controlling a drum brake of an automobile according to claim 3, further comprising the step of feeding back wear, specifically: In the braking process, the abrasion condition of the brake is judged through feedback data of a displacement sensor (8) and a force sensor (7), displacement quantities L 1 and L 2 of a first brake shoe (2) and a second brake shoe (3) are recorded through the displacement sensor (8), L 1 and L 2 are compared, a larger displacement quantity is recorded as L b , a smaller displacement quantity is recorded as L s , whether L b is smaller than a maximum displacement threshold value L max is judged, if yes, whether L s is larger than a minimum displacement threshold value L min is judged, if no, the brake is faulty at the moment is represented, if L s is larger than a minimum displacement threshold value L min , the brake is good at the moment, and if not, the brake is faulty at the moment; Setting a fault tolerance value x, defining the maximum value of tension values received by a return spring (53) through a force sensor (7) as N, comparing the tension values received by the return spring (53) with tension threshold values N-x respectively, and if the tension values are smaller than the tension threshold values N-x, indicating that the brake shoe corresponding to the return spring (53) is worn, and feeding back a wear signal to a driver.

Description

Automobile drum brake and control method thereof Technical Field The invention relates to an automobile drum brake and a control method thereof, and belongs to the technical field of brakes. Background In the background of rapid development of electric automobile technology nowadays, electric control intelligent automobile technology is increasingly applied to automobiles. The drive-by-wire technology is a novel control system based on an information interaction system and real-time control. The brake-by-wire technology includes EHB and EMB. The EHB is a braking system combining traditional hydraulic control and electric control, and the EMB controls an electromagnetic valve of a brake through an ECU, so that friction plates of the brake are contacted with a brake disc, and braking is realized. However, with the comprehensive application of the electric control technology, the EMB is more precisely controlled and is suitable for the development direction of the intelligent electric automobile because of the convenient arrangement, and is the main development direction of the linear control technology. The EMB abandons traditional hydraulic and pneumatic control and related components, and the braking is completed by controlling related mechanical structures through electric signals. The drum brake uses a brake transmission mechanism to enable a brake shoe to press a brake friction plate on the inner side of a brake drum, so that braking force is generated, and an automobile brakes according to requirements. Conventional drum brakes often perform a braking operation by hydraulic transmission, the rotating element being a brake drum and the stationary element being a brake shoe. However, conventional drum brakes using hydraulic braking have not been suitable for the current development of electromechanical braking, and in order to further respond to the development of a brake-by-wire chassis, the drum brakes need to be electrically controlled. However, the electronic wire control technology also has a certain problem, namely when a motor or a circuit fails, the braking requirement cannot be successfully completed, the fault tolerance of the system is insufficient, the patent with publication number CN107725638A discloses a structure of a brake shoe and a friction plate, the problem that the replacement period of the friction plate is short and the service period of a brake is short is overcome, but under the working condition of parking locking, the brake shoe is only supported by a cam mechanism to brake, the reliability of parking locking cannot be ensured, meanwhile, the braking effect is unreliable, and the inaccuracy of the abrasion judgment of the brake is caused, and although the replacement period of the friction plate can be improved, the abrasion degree of the brake shoe cannot be accurately judged, so that the brake cannot be maintained in time. Disclosure of Invention The invention aims to: aiming at the defects in the prior art, the invention provides the automobile drum brake and the control method thereof, and the problems that parking locking is unreliable and the abrasion degree cannot be judged are solved by arranging the self-locking assembly on the cam device, controlling the forward and reverse rotation of the cam device through the driving motor and adopting the displacement sensor and the force sensor to jointly detect the abrasion degree. According to the technical scheme, the automobile drum brake comprises a brake bottom plate, first brake shoes, second brake shoes, a driving assembly and a resetting assembly, wherein the first brake shoes and the second brake shoes are oppositely arranged on the brake bottom plate along the longitudinal axis of the brake bottom plate, the resetting assembly is arranged between the first brake shoes and the second brake shoes, the driving assembly is symmetrically arranged along the transverse axis of the brake bottom plate, the driving assembly comprises a cam device and a driving motor which are connected with each other, a self-locking assembly is arranged on the cam device, and contacts at two ends of the first brake shoes and the second brake shoes are respectively contacted with the cam device. According to the invention, the double motors are adopted to control the forward and reverse rotation of the cam device, and the self-locking assembly is arranged on the cam device, so that the reliability of parking locking is improved, the parking locking function can be realized without an additional system, the production cost is reduced, the whole structure is simple, and because the double motors are adopted to control, the double motors are equivalent to a redundant system, if one motor fails, emergency temporary braking can be finished through the original structure by a single motor, the fault condition is processed, and the fault tolerance and the safety of the system are improved. Preferably, in order to drive the first brake shoe and the seco