新能源轿车盘式制动器设计毕业论文
2021-04-08 00:41:02
新能源汽车盘式制动器设计
学院(系): 国际教育学院
专业班级: 车辆gj1502
学生姓名: 唐文宇
指导教师: 杨 莹
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Summary
The automobile brake system plays an important role in ensuring the safety of the vehicle, the reliability of the parking and the economic benefits of transportation. With the rapid development of the expressway, the increase of the speed and the increasing traffic density, the brake system of the automobile Work reliability is becoming increasingly important, so many brake regulations place many detailed and specific requirements on the brake system. The stable braking performance of the disc brakes has gradually replaced the drum brakes. Therefore, it is important to design a disc brake that is stable and safe and reliable. With the increase in the level of highways, the rise in the number of passengers, especially the enforcement of national safety regulations, the use of disc brakes in the front and rear wheels will be a trend. In this design, reference is made to the design concepts of some foreign advanced disc brakes. Through the analysis of the main parameters of the brake system, it is determined as the floating caliper disc brake, and the structural analysis and design calculation are carried out, and the assembly drawing of the front wheel brake and the parts drawing of the brake disc are drawn, and the relevant evaluation indexes are also complete. meets the. The final design of the brakes basically achieved the desired goal.
Keywords: disc brake; parameter design;performance;check Contents
ChapterⅠIntroduction 1
1.1 The meaning of brake design 1
1.2 Brake development history 1
1.3 Application of domestic disc brakes 2
1.4 Application of foreign disc brakes 5
1.5 Current development status of brakes 7
Chapter II Structure and Design Principles of Brakes 17
2.1 Automotive brake system function and classification 17
2.2 Classification and introduction of disc brakes 17
2.3 Disc brake structure and working principle 20
2.4 General principles of brake design 21
2.4.1 Brake performance 21
2.4.2 Brake performance stability 22
2.4.3 Brake clearance adjustment simplicity 22
2.4.4 Brake size and quality 23
2.4.5 Noise reduction 23
Chapter III Brake Design 24
3.1Design Parameters 24
The original parameters of this design refer to the design specification. 24
3.2 Main components of disc brakes 24
3.2.1 Brake disc 24
(2) Brake disc thickness h 26
3.2.2 Brake block 28
3.2.3 Brake caliper 28
3.2.4 Pad alarm device design 29
3.2.5 Friction material 30
3.2.6 Brake clearance and adjustment 30
3.3 Brake force distribution analysis 31
3.4 Selection of synchronization adhesion coefficient 32
3.5 Brake performance factor 33
3.6 Brake braking torque calculation 34
3.7 Brake system performance requirements 34
3.7.1 Requirements for directional stability of the car during braking 35
3.7.2 Brake deceleration j requirement 36
3.7.3 Braking distance S requirements 36
3.7.4 Brake torque requirements 37
3.7.5 Specific energy dissipation rate requirements for wheel brakes 37
3.7.6 Comparison of friction requirements 37
3.7.7 Requirements for heat flux density 37
3.7.8 Requirements for the absorption power of the pad 37
3.7.9 Average friction requirements 37
3.7.10 The service brake has at least two independent drive lines 37
3.7.11 Prevent water and sludge from entering the brake working surface 38
3.7.12 Requires good thermal stability of braking capability 38
3.7.13 Lightweight operation 39
3.7.14 Calculation of pedal force during emergency braking 39
3.7.15 Brake pedal travel calculation 39
3.7.16 Subsidiary calculation 40
3.8 Friction lining wear characteristics 40
4.1Brake heat capacity and temperature rise accounting 43
4.2 Brake commissioning 44
4.2.1Technical requirements for brake discs 44
4.2.2 Brake caliper technology assembly requirements 44
4.2.3 Hub assembly technical requirements 45
Conclusion 47
References 48
Acknowledgement 51
Chapter Ⅰ Introduction
1.1 The meaning of brake design
Cars are the most common and convenient transportation tool used in modern transportation. The car brake system is an important system on the car chassis. It is a device that restricts the movement of cars. The brake is also a key device in the brake system that directly restricts the movement of the car, and is the most important safety component in the car. The braking performance of a car directly affects the driving safety of the car. With the development of the road industry and the increasing traffic density, people are increasingly demanding safety and reliability. To ensure personal and vehicle safety, a very reliable braking system must be provided for the car. By consulting relevant materials, using professional basic theory and expertise to design and calculate the components, the following requirements are met: sufficient braking performance to ensure the safety of the car; at the same time, the choice of materials should be used as much as possible. A material that is harmless to the human body 【1】.
1.2 Brake development history
The brake is divided into a wheel brake and a central brake, the latter brake drive shaft or transmission output shaft. Since the central brake is prone to overloading the drive shaft during emergency braking, most heavy-duty vehicles now have a manual mechanical drive mechanism attached to the rear brake to make the parking brake and emergency brake 【2】. From the way of dissipating energy, the brakes are frictional, hydraulic, electromagnetic and eddy. Holograms, laser Doppler analysis, finite element analysis, and experimental modal techniques have been introduced into the vibration and noise research of brakes so far and a great deal of results have been achieved. Holographic technology shows the true form of vibration during braking; the unification of finite element and modal analysis makes it possible to establish a mathematical model of vibration that is consistent with reality, which provides for the design and analysis of the braking system. convenient.
The dynamic characteristics of the system need to be given when analyzing, synthesizing and predicting the system. At this point, the actual system may not be completed or cannot be verified by experiments due to factors such as economy and safety. It is often necessary to implement this requirement by means of system simulation. The so-called system simulation refers to the use of a computer to run a simulation model, imitating the actual system's operating state and the process of changing with time, and through the observation and statistics of the simulation running process to obtain the simulated output parameters and basic characteristics of the simulated system, To infer and estimate the actual parameters and real performance of the actual system. When using the simulation method to study the performance of the car, it is necessary to simplify the car appropriately, and then apply the simplified model for calculation and analysis. With the degree of simplification, there will be different degrees of deviation between the calculation results and the actual situation. Since the automobile is a complex system, the motion model and mechanical model of the whole vehicle, parts and assemblies are quite complicated. The amount of work required to analyze and calculate these models while ensuring a certain precision is very large. It is largely limited by the processing power of the computer.
With the development of computer hardware and software technology, the computer's ability to process data has improved by leaps and bounds. Therefore, computer simulation technology is increasingly used in research and development and design and manufacture of automobiles. In recent years, Virtual Prototype Technology has been rapidly developed. Virtual prototyping technology can be used to comprehensively consider the nonlinear load, stick-slip effect, structure and other factors of the brake, and analyze the main causes of brake vibration under specific conditions. Virtual prototyping technology has become a fast and effective means to solve engineering problems 【3】.
1.3 Application of domestic disc brakes
With the development of China's automobile industry technology, especially the development of the heavy-duty automobile industry, the introduction of joint ventures, the entry of foreign advanced technology, the application of disc brakes in automobile mining has gradually formed a scale in China. In particular, it has played a significant role in improving vehicle performance, ensuring safety, improving rider comfort, meeting people's increasing living material needs, and improving living environment.