| Brakes are one of the most important safety and performance components in automobile. And it is necessary to research on braking reliability and braking efficiency. Using the air disc brake YF3501AD01 for reference, the CAD model, dynamic model and thermodynamic model of the air disc brake are established. The dynamic and thermodynamic characteristics of the air disc brake are analyzed in the braking process.The CAD model of the air disc brake is established through the software UG and it shows the structural characteristics of the air disc brake, the shape of the components and the assembling relation among the components.Based on the structural characteristics and working principle of the air disc brake, the dynamic model of the air disc brake is established through the software ADAMS. After the dynamic simulation of the braking process, the dynamic characteristics of the air disc brake in the braking process are analyzed, i.e. the braking time, the angular speed of the brake disc, the angular acceleration of the brake disc, the normal force and friction force between the brake disc and the pad and the braking torque of the brake disc are analyzed. Based on the dynamic analysis, the structure of the lever of the air disc brake is optimized. On condition that the braking time is equation, the ratio of the normal contact force between the brake disc and the pad to the force supplied by the brake chamber is increased by about 25%.Based on the generation and distribution theories of frictional heat of the brake in the braking process, the thermodynamic model of the air disc brake is established through the software ANSYS/LS-DYNA which is the finite element software mainly used the explicit integration method, and the temperature field of the disc brake is analyzed by the direct thermodynamic coupling method which considers the effect of heat expansion of materials. In the thermodynamic model, the relation of generation of frictional heat between the brake disc and the pad is defined, and the convection coefficient and radiation coefficient that are changed with rotation speed of the brake disc and surface temperature of friction pairs are defined, and the contact normal forces of the double surfaces of the brake disc supplied by the piston and the caliper respectively are defined. After the thermodynamic simulation of the braking process, the thermodynamic characteristics are analyzed, i.e. the surface temperature and the axial surface temperature and the inner temperature of the friction pairs. Due to the complex effect of frictional heat and heat convection, the highest surface temperature of the brake disc and the pad is located in the middle segment along the radial direction, and the temperature falls from the middle segment to the inner radius or from the middle to the outer radius along the radial direction. The effect of the material parameters on the temperature field of the air disc brake is analyzed through changing the material parameters in the thermodynamic simulation, and it is found that the surface temperature falls as the specific heat and heat conduction coefficient of the friction pairs increase and that the coefficient of thermal expansion of frictional material has a little effect on the temperature field.
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