Research On Braking Performance And Reliability Analysis Of Wet Multi-disc Brake

The wet multi-disc brake is a key component of the mechanical transmission system.Because of its large braking torque,stability and reliability,it is widely used in heavy vehicles,construction machinery,and marine equipment.However,with the development of wet multi-disc brakes in the direction of lighter weight and higher speed,the working environment of brakes has become more and more complicated,and various failure problems such as friction component vibration,deformation,and ablation often occur in the brakes.This article is based on the wet multi-disc brake of a marine crane as the research object.Through dynamic and kinematic analysis,the braking performance of the brake under different braking conditions is studied.At the same time,the reliability of the brake is analyzed according to the structural performance and thermal characteristics of the friction component,and the structure optimization design of the brake friction component is carried out according to the analysis result.The main research contents and results of this paper are as follows:(1)Based on the fractal contact theory and the determination of the surface fractal parameters of the friction component,the surface profile of the friction component is simulated according to the W-M fractal function,the normal contact stiffness between the steel disc and the steel disc is obtained through the fractal contact model,and the normal contact stiffness between the other friction components is obtained according to the Hertz contact theory.The friction factor of the brake friction pair was determined by the pin-disk experiment analysis,and the spring stiffness of the pressure spring was measured by the tension machine,and the compression stiffness of the pressure spring was obtained,which laid the foundation for establishing a reliable dynamic model of the brake system.(2)Based on the key parameters obtained,the dynamic model and kinematics model of the wet multi-disc brake are established.The different braking conditions in the actual brake work are analyzed,and the braking conditions under general braking conditions and emergency braking conditions are respectively analyzed.Dynamic simulation analysis of the brake system is carried out,and the braking characteristic curve of the key components of the brake is obtained.The analysis shows that the friction component will vibrate during the braking process,and the pressure spring will cause the fluctuation of the axial load to affect the stable contact of the friction component,thereby affecting the braking performance of the brake.(3)The finite component model of the friction component was established,and the modal analysis of the friction component was carried out.The accuracy of the finite component model of the friction component was verified by the natural frequency test of the thin disc components.Based on the accurate and reliable finite component model,the flexible body file of the steel disc was generated and the rigid-flexible coupling dynamic analysis of the brake system was completed.The dynamic joining process and structural performance of the steel disc in the friction process were studied.The temperature rise of the friction component under emergency braking conditions is simulated and analyzed,and the reliability of the brake is studied.(4)The structure of the friction components of the wet multi-disc brake is analyzed and researched.First,the arrangement of the friction components is studied.New arrangements of friction pairs are designed by changing the axial arrangement of the steel disc and the friction disc.The research analyzes the influence of the arrangement of friction components on the braking performance of the brake,and selects the best arrangement of friction components according to the analysis results.According to the dynamic and thermal characteristics,the structure of the friction component is designed,and the optimized design of the wet multi-disc brake is researched through the rigid-flexible coupling dynamics analysis and thermal characteristics analysis.The verification shows that the braking performance and reliability of the brake after the optimized design of the friction component structure are significantly improved.