| Nowadays,automobile has become an indispensable means of transportation in people’s life.In order to ensure the safety of automobile driving,the development of excellent service braking system has become the focus of automobile design.Wedge brake has high benefit,low cost,excellent braking performance and outstanding advantages in lightweight.Taking the rear wheel wedge brake of commercial truck as the research object,this paper optimizes the structural parameters of wedge brake,and uses the finite element method to simulate and analyze it.Finally,the performance bench test of wedge brake assembly is used to verify the theoretical analysis and simulation results.The main work and research results are as follows:(1)Using the structural analysis and design calculation method of automobile braking system,the mechanical analysis of wedge brake is carried out.The key components of wedge brake are designed,including wedge opening mechanism,brake drum,friction lining and brake shoe.Finally,the three-dimensional modeling is carried out by using SolidWorks.(2)The braking efficiency is selected as the main performance index.According to the general method of braking efficiency factor of brake,the braking efficiency factor of wedge brake is deduced,and the structural optimization model of wedge brake is established.The optimization model is solved by genetic algorithm,and the optimal crossover probability and mutation probability of genetic algorithm are analyzed by comparison.The results show that the optimized braking efficiency factor is greatly improved.(3)Based on the optimization of structural parameters of wedge brake,the performance simulation analysis of the optimized wedge brake is carried out in three aspects: statics,mode and thermal structure coupling.The static analysis results show that the contact state of the leading shoe is better than that of the slave shoe,the contact stress is small,and the key parts of the wedge brake meet the requirements of strength and stiffness.Then the modal analysis of the brake shoe and drum is carried out,and the natural frequencies and vibration modes of the brake shoe and drum are obtained.Finally,the thermal structure coupling analysis of wedge brake under emergency braking condition and repeated braking condition is carried out,and the temperature nephogram and stress nephogram of brake drum are obtained.It is found that the maximum stress under thermal effect is greater than that under static analysis.(4)According to the technical requirements and bench test method of commercial vehicle service brake,the evaluation index of brake performance test is calculated.Through the bench test of wedge brake performance,the simulation results and experimental data analysis show that the simulation results are close to the test results and reasonable.To sum up,after the structural parameters of wedge brake are optimized,its braking performance is improved.The simulation results are similar to the test results,which has theoretical and practical significance.It provides design experience for the development of a series of subsequent products and can reduce the R &D cost and design cycle. |
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