Analysis And Optimization On The Structure Of Speeding-increasing Gearbox

Transmission gearbox is one of the important parts of automobile drive system, its main functions include changing torque, rotational speed and the direction of drive wheel. Transmission condition have direct effects on the overall performance of the car. The transmission test bench an important means of studying bearing capacity, performance improvement and optimization design. Based on the analysis and reference to domestic and foreign transmission test bench,this paper analyze on the overall scheme design of transverse precursor transmission load test bench and carry on the thorough analysis on the part of gearing up box of the test bench.As an indispensable part in mechanical equipment transmission system,gear case connect and transmit power, its level of design and manufacturing technology,to some extent, reflects our country’s comprehensive national strength and market competitiveness. With the rapid development of science and technology, new requests have been put forword on the sides of transmission power, small volume, light weight, small vibration, low noise. Step-up gear box as the input power and motion transmission test bench unit, due to its high working speed, gears in meshing process will produce vibration shock, the impact is passed on to the gear box casing through the shaft and bearing which causes vibration. The vibration can esaily cause the fatigue damage of box body, and reduce the service life of the gear box. Therefore, it is necessary to study the dynamic characteristics of a gear box and structural optimization.The paper firstly design the internal parts of the growth in the box and its structure according to the actual needs, using Pro/E5.0 software to build 3 d modeling and virtual assembly, using ANSYS software Workbench14.0 growth of gear box of a one-to-many tooth meshing of the gears on the nonlinear finite element contact analysis, the calculation results are intuitive and effective for gear contact stress analysis and strength check.The finite element statics analysis on growth box is carried out, determine the deformation and stress of box body size, according to the data of strength and stiffness,which analyze on the box body, all allowance is meet the requirements of gear transmission system.In order to estimate the dynamic characteristics of the gear box, using the ANSYS software to carry out the Modal analysis on it. Using block Lanczons method to extract the first ten order modes. From the results, the first two experimental rotating speed of vibration frequency are close to the natural frequency of the gear box, and easy to resonate. Due to the work speed is scheduled by the standard of test bed, to avoid the resonance can only by changing the natural frequency of the box body. By researching on the casing wall thickness and steel plate thickness separately, identified the two elements are proportional to the body’s own natural frequency. Finally, reduce the wall thickness and steel plate to 6 mm at the same time, avoidind the resonance range of successfully. The modal natural frequency of optimized gear box can avoid the meshing frequency and the frequency doubling, solved the resonance problem.