Research On Parking Brake Automatic Adjustment System

The adjustment quality of the parking brake system not only directly affects the vehicle parking performance,but also is one important factor that influence the stopping force of parking brake.In order to improve the adjustment quality of the parking brake system,eliminate the influence of human factors,improve the degree of automation in the automobile production line,developing a set of automatic parking brake adjustment system which has high efficiency and good quality is very practical value.The research of a series models in the parking brake system structure and manual adjustment process,put forward the design scheme of the parking brake automatic adjusting system which can meet the requirements of vehicle assembly line to improve the adjustment quality consistency of parking brake system,reduce the labor intensity of workers.The main research work was described as follows:(1)Firstly,according the requirements of the automatic adjustment system,and according to the requirements of the system,the hardware were designed.The standard parts such as the motor,reducer and torque sensor were selected by calculating the rated torque required during the adjustment of the parking brake system.According to the structure of the brake handle and the inner floor of the car,and the non-standard parts such as the handle holder,the ratchet lock release device,dedicated stent of the adjusting nut control mechanism were designed.The control of the switch,control of the light and emergency control of motor for brake handle were designed.Based on the work flow of the whole system,the necessity and control strategy of emergency stop in the system emergencies were studied.The control strategy of automatic termination operation under the moment overload was studied,and the corresponding software development was completed on the basis of LabVIEW platform.(2)Secondly,aiming at the problem of turning the steering mechanism of the brake handle,the mechanical analysis of the brake handle mechanism and the method of turning the steering mechanism to the operation were put forward,and the handle holder structure was improved according to finite element analysis by using WORKBENCH.The speed S curve planning of the brake handle was put forward to reduce the vibration and shock during the movement of the brake hand control mechanism.In order to reduce the vibration and shock during the movement of the brake handle,the S curve of the brake handle was proposed.The S curve was designed by MATLAB,respectively obtained the jerk of the brake handle pulled to the second ratchet teeth and the eighth ratchet teeth,and through Simulink the designed curve were verified.(3)Finally,the bench test was carried out on the parking brake automatic adjustment system.Adjusted the test vehicle with the automatic adjustment system,found that some adjustment results were out of substandard products,and the reason was that the torque sensor monitoring value was unreasonable when the adjustment nut was finally tightened,and the value was improved.Conducted CPK analysis for manual adjustment and automatic adjustment,and verified the reliability of the automatic adjustment system.Measured the tension at different teeth,and verified that the consistency of the automatic adjustment was better than the manual adjustment.The error analysis were carried out.Based on the "three-point method",the measurement method of handle cable preload was put forward.The results of test showed that the automatic adjustment was better than the manual adjustment,and the consistency of the parking brake system had obvious improvement.So the parking brake automatic adjustment system has engineering application value.