Research Of Force Transmission Performance Of Marbles Disk Pressing System

Due to the increase of the weight and the speed of tracked vehicle and the quantity of precision instruments in tracked vehicle, a higher standard for the performance of brake is required. The dry disk brake is applied to high speed tracked vehicle because its instant increase of temperature is small during braking process and its braking performance is stable. The marbles disk pressing system is an important component of the dry disk brake, and its performance affect the brake effectiveness. Force transfer efficiency and lifespan of the marbles disk pressing system are major parameters to evaluate its performance. But the force transfer efficiency is unstable and the lifespan is unsatisfactory because the value of stress and strain in contact zone between marbles disk and marble is too great. Therefore, the improvement of the marbles disk pressure mechanism is required.In this paper, force and the mode of motion of marble and marbles disk are analyzed first, and then a testing system is designed and manufactured that can measures force transfer efficiency and contact deformation value of the marbles disk pressing system. The force transfer efficiency of several typical marble disk specimens is measured by the testing system. Using the measurement results, the factors that influence the transfer efficiency are analyzed. At last a finite element model is established using ANSYS software to calculate the value of stress and strain in contact zone between marbles disk and marble. The finite element model is validated by the testing system, and then is used to analyze the real marbles disk pressing system and a modified one, the roller disk pressing system. Following are the main results:1. The motion of marble in the marbles disk is complicated, containing rolling and sliding. Without regard to contact deformation, amplificatory efficient is mainly affected by the marbles disk slot angle, friction coefficient, arc radius of marble groove, radius and mass of marble, mass and rotational inertia of marbles disk. The classic hertz contact model is not suitable for analyzing the contact between marbles disk and marble.2. The testing system can measure the force transfer efficiency and contact deformation value of the marbles disk pressing system and the results showed that, as the load increases, the force transfer efficiency in the contact pairs of various marbles disks decline; when the load is small, the force transfer efficiency has been less affected by the material of marbles disk (38CrSi and GCr15); as the load increases, the decline of the force transfer efficiency of GCr15 marbles disk is smaller than 38CrSi marbles disk; the force transfer efficiency of marbles disk specimen whose the marbles disk slot angle is 25° is generally lower,compared with marbles disk specimen whose the marbles disk slot angle is 15°.3. The finite element model is valid to calculate stress and strain of the marbles disk pressing system. The contact stress of the roller disk pressure reduces by 58% compare to the regular marbles disk.