Theoretical Analysis And Experimental Research On The Marble-marbles Disk Pressure Mechanism

A type of dry-chip brake has a smooth braking effect,a low brake instantaneous temper-ature rise,a long stable working time in a harsh environment,and is widely used in some large-tonnage and high-speed vehicles.The marble-marbles disk pressure mechanism is the core component of this type of dry-chip brake,therefore,the research on the marble-marbles disk pressure mechanism is of great significance.In this paper,the research goal is to improve the transmission efficiency,force increase efficiency,reduce the failure rate and prolong the service life of the marble-marbles disk pressure mechanism.The objectives above are studied from three aspects:theoretical analysis,simulation analysis and test verification.(1)Theoretical analysis shows that the movement state of the marble in the marble slot during the working process of the marble-marbles disk pressure mechanism is rolling and sliding coexist,and the stress expression between the marble and the marble slot is derived,let the rotation angle of the rotating disk in the formula be an independent variable,the stress be the dependent variable,and the others be constants,the stress between the marble and the marble slot changes with the rotation angle of the rotating disk,the relationship can be ob-tained in this way,compared with the ANSYS Workbench dynamic simulation results:the theoretical calculation results are bigger than the simulation results,but as the rotation angle of the rotating disk increases,the deviation between them gradually decreases.Although the the-oretical calculation results are not completely accurate,the overall trend is correct,it can be used to analyze the sensitivity of the stress between the marble and the marble slot,and to provide direction for the optimal design.(2)The movement state of the marble in the marble slot has certain randomness,and when optimizing the marble-marbles disk pressure mechanism,try to ensure that the shape of the marble is a standard sphere.Let the marble radius of the expression be the independent variable,the stress between the marble and the marble slot be the dependent variable,the oth-ers be constants,and obtain the relationship between the stress and the radius of the marble.According to the variation law of the curve,it can be seen that when the radius of the marble is small:the stress between the marble and the marble slot drops sharply with the increase of the radius of the marble,and gradually becomes gentle at the later stage.The simulation results show that moderately increasing the radius of the marble,moderately increasing the radius of curvature of the marble slot,and reducing the difference between the radius of the marble and the radius of curvature of the marble slot is beneficial to reduce the stress between the two and alleviate the stress concentration at the same time.(3)The transfer efficiency test and the run-in strengthening test were carried out on the marble-marbles disk pressure mechanism by using the built-in marble-marbles disk pressure mechanism test bench.In order to ensure the validity of the test data,both the mechanical in-stallation and the software control were furthest consistent with actual vehicle use.And two sets of three transfer efficiency tests were carried out before and after 530 run-intensification tests.The two sets of tests were compared and concluded that after a total of 530 times mild,moderate and severe running-in strengthening,the transfer efficiency of the marble-marbles disk pressure mechanism was improved by 3.09%,and the running-in strengthening effect was remarkable.