The 21st century is an era of rapid development of automobile industry, which has gradually become a pillar industry in many countries. With the rapid development of China's national economy, the annual output and social ownership of automobiles are also growing rapidly. The quality of automobile is related to whether China's automobile industry can stride into the world. Therefore, the improvement of automobiles and related products is also very important.

Since the birth of automobiles, vehicle braking system plays a vital role in vehicle safety. In recent years, with the advancement of vehicle technology and the improvement of vehicle speed, this importance has become more and more obvious. In order to cope with the threat of high speed to people's safety, many regulations put forward higher requirements for vehicle safety, and the working reliability of automobile brake system becomes one of the most important aspects. The braking performance of automobiles is also regarded as the performance index of the seven major automobiles. Its function is to ensure the safety performance of automobiles. Automotive brake system is composed of many parts, and automobile hand brake arm is one of the essential parts. The function of brake system is to force the vehicle to slow down or stop, to keep the speed of downhill vehicle stable, and to keep the parked vehicle stationary in situ (including on the slope). As the core component of parking brake system, hand brake control arm ensures the braking stability of automobiles, and is also the last guarantee of people's life when driving. Studying the structure of passenger driver brake arm assembly not only affects the high efficiency and long-life operation of automobile brake system, but also directly relates to the safety of automobile driving. Continuous improvement and improvement of automobile hand brake arm is ultimately an indispensable task in the process of automobile design.

The development level of a country's automobile industry reflects the overall industrial level of the country. To develop a country's automobile industry, as far as the automobile industry is concerned, automobile design should be in a pivotal position. The design of brake arm is an important part of automobile design, especially with the development of modern automobile technology, the improvement of road conditions, the increasing speed and safety issues, which is an important component affecting automobile safety. Hand brake arm is an important part of parking brake system. Its efficiency and reliability are related to parking brake. In emergency situations, it also has the ability to limit high-speed driving of vehicles. Its quality and safety are very obvious. Therefore, in the process of rapid development of the automobile industry, we need to be more strict about its safety and reliability.

At the same time, as a mechanical component, the hand brake arm bears alternating cyclic loads, and fatigue damage is the main failure mode. Because of the frequent use of the hand brake in the driving process of the car. In order to avoid fatigue failure and give full play to the various properties of materials, the analysis of fatigue life has become an increasingly important part of Engineering design, which is also one of the important contents of this topic, to ensure the reliability of vehicle braking. To sum up, improving the efficiency and reliability of hand brake control arm is an indispensable part of improving vehicle braking performance, which is also the significance of studying the structure of passenger hand brake arm assembly.

Handbrake is specially called auxiliary brake, which is different from the principle of brake. It uses steel wire to connect to the rear brake shoe to brake the car. Manipulator brake is the parking brake that we will see in most models. It is almost the "standard" of automobiles. The common hand brake is located in the driver's right hand droop position, which is convenient to use. The function is to stabilize the vehicle after the vehicle stops, so as to avoid the accident caused by the car sliding on the slope road or when parking. For small cars, some of the traditional hand brakes have a brake disc at the rear of the gearbox where it is connected with the transmission shaft, which is similar to the disc brake and then drives the tension to it through the steel cables, thus realizing parking brake. After pulling the hand brake, it uses a hydraulic auxiliary cylinder to drive the hydraulic main cylinder under the car, then drives the pneumatic valve, and then after the pneumatic valve moves, the brake transmission shaft is braked. When the brake transmission shaft is completed, if it is an ordinary truck, the long-term brake is pulled by the steel cable of the hand brake rod. If it is a high-grade truck, the electric control is used. When pushing the hand brake, the electric control is used. The electric tractor has been started. After the air braking is completed, the cable is pulled close and locked. Because the traditional bar brake is short and easy to operate, it has been favored by people all the time. But long-term use of the hand brake will cause plastic deformation of the steel wire. Because this deformation is not recoverable, long-term use will reduce the utility and increase the stroke of the hand brake.

With more and more attention paid to the safety of automobiles, people's requirement for the braking performance of automobiles is also increasing day by day. For this purpose, American Tianhe Automobile Group has successfully developed and first introduced the electronic parking braking system of automobiles. It replaces the original mechanical structure with the electronic control system, making the parking control of vehicles more convenient and safe, and at the same time, it can be compared with the electronic parking braking system of automobiles. His electronic control system works together to make the car more intelligent. Compared with the traditional mechanical parking brake system, it has many shortcomings, such as the need to consume the physical strength of the driver, the operation is more troublesome, the need for a driver to have certain skills when starting on the ramp, and the mechanical structure in use will have certain security risks and so on, while the electronic parking brake system can effectively overcome these problems. It can realize the functions that mechanical parking brake system can not achieve, such as slow braking, intelligent ramp start, data exchange and sharing with driving computer. Compared with the main parts of automobiles such as frame, chassis and engine, there are few achievements in electronic parking technology in China at present, and they are generally in experimental state. For example, Xin Jianfang and Li Wei have made in-depth research on the application layer protocol of electronic parking system, improved the hardware design of communication interface circuit, and further realized intelligent control on the basis of the integration of executing agencies. Xun et al. made a thorough study on the switch control of the electronic parking system, and obtained the advantages and disadvantages of the switch control electronic parking system through simulation and experimental data analysis. Yuan Yong and Cai Jing et al. designed the experimental platform for the electronic parking system, and used the platform to simulate the control strategy of the electronic parking control system, and established the simulation model based on the experimental platform. Type. However, the traditional mechanical handle is cheap and easy to install, which is also the reason why it is still widely used, so it is meaningful to improve the traditional parking brake handle. Some scholars have made great efforts to lighten and optimize the structure of the control handle. For example, in 2008, Li Yuan and others completed the three-dimensional model of the parking brake handle considering the non-linear state and material factors, and analyzed the residual stress and strain of the whole structure under lateral and lateral stress conditions respectively. In 2010, Han Ji aimed at the car parking in China. The problems existing in the experimental system of vehicle brake control mechanism assembly are studied. The mechanical structure, electrical control part, loading control part and stress and strain detection part of the experimental system are designed respectively. For the optimization design of parking brake control handle, Chery Automobile, Beiqi Automobile Company have also designed and applied for patents.

Modern automobiles have been more and more widely used in the electronization of mechanical control. From basic electronic direction assistance to complex active steering proportional control, these parts used to be mainly hydraulic and mechanical control, but also gradually close to electronic control. Almost all large automobile manufacturers have invested a lot of energy and money in electronic parking, and the technology has achieved initial results internationally. In recent years, some automobile companies have applied for patents in EPB brake devices, mainly involved in Continental Teves, Eaton, Siemens and so on. According to the current research, EPB brake system can be divided into two categories. One is that the brake motor directly pushes the actuator to act on the brake disc. The parking brake produced by Continental Teves Company is a typical one. The second is that the motor first acts on a force amplifier, which produces braking force on the brake disc. These two mechanisms have their own advantages and disadvantages. The first type is simple in structure and stable in operation, but it requires the motor to generate a large thrust to achieve parking braking, resulting in excessive energy consumption, while the motor is very large in volume and weight, which is inconvenient. The second one can effectively reduce energy consumption, but due to the increase of the booster mechanism, the structure is complex and the braking stability is not as good as the first one. With the widespread use of automotive electronics, electronic parking brake system will become more and more popular. It can be said that electronic parking brake system is another embodiment of humanization and intelligence in the application of vehicle system, and the market performance also fully demonstrates the success of the application of electronic parking brake system.

Whether electronic handbrake or traditional handbrake, they have their own characteristics, but also have their own research significance. The difference between the electronic hand brake and the mechanical handbrake lies in the great difference in function. The safety and reliability of the electronic hand brake belong to the mechanical handbrake, while the electronic hand brake is more convenient. In the future, the traditional handbrake will not be completely replaced by the electronic handbrake, but I believe that with the continuous development of automotive electronics and the maturity of vehicle technology, the electronic hand brake can break through the original limitations and become safe, efficient and simple and convenient.

2. 研究的基本内容与方案

2.1 Basic Contents of Research

This topic is to study the structure of hand brake assembly of light passenger car, determine the research content according to the actual needs of the driving process, and make it efficient and reliable according to the research status of hand brake arm. The main contents include: