Research On Finite Element Thermal Analysis And Gear Profile Modification Of High-Speed Gears

Significant temperature field of high-speed gears is produced when transmission. Temperature of high-speed gears have important influence on gear transmission performance, scuffing failure, the leakage of lubricating oil. Thermal deformation caused by temperature field should be considered when gear profile modification which used to improve meshing impact is carried out. So in the paper, finite element thermal analysis of high-speed gears is done to obtaine temperature field and influence factors laws, and gear profile modifications is done acorrding to thermo-elastic coupling analysis. The contents and conclusion are as follows:Temperature field finite element analysis of involute cylindrical high-speed gear is conducted by using ANSYS, and bulk temperature distribution regulation on driver and passive gear tooth is obtained. Bulk temperature peaks (about 80?) appears on meshing in and out region of tooth root and tooth top of driver and passive gear. Bulk temperature on pitch curve region is lower. Along tooth width direction, the temperature on middle region is higher than temperature on gear end-face.Analysis on the effect on gear temperature of rotation rate, torque, tooth width, modulus, air and lube oil temperature, heat transfer coefficient on gear surface and field of conjugate action is done. The temperature on tooth surface increase as rotation rate or torque increases, and the temperature increase amplitude on different position of tooth surface is not same, temperature increase amplitude decrease as rotation rate or torque increases. The temperature on tooth surface uniformly increase when tooth width increases. The change of modulus cause the change of volume, load, heat transfer coefficient, and temperature on tooth surface decrease and then increase as modulus decreases. When rotation rate or torque is higher, the effect on gear temperature of rotation rate, torque, tooth width, modulus become bigger. The maximal bulk temperature increases or decreases as air and lube oil temperature, and the change has nothing with rotation rate or torque. The effect on gear temperature of heat transfer coefficients is relatively small, and temperature decreases as heat transfer coefficients increase.Gear thermo-elastic coupling analysis is doen by using indirect coupling mothed of ANSYS. Thermo-elastic deformation on the starting and ending point of single tooth meshing region of driver and passive gear which is not equal along tooth width direction is obtained. And thermo-elastic deformation in middle region is less than along tooth width direction. The maximal modification amount is obtained according to thermo-elastic deformation, and the three elements of tooth profile modification are also obtained. Then the gear profile modification is done.Dynamic simulation analysis of gear before and after modification are done by using ANSYS/LS-DYNA, and tooth meshing force curve and gear tooth stress on the moment of meshing in and out before and after modification are obtained. Temperature field finite element analysis of gear after modification is carried out. Results comparison show that meshing force curve and tooth stress on the moment of meshing in and out decrease, and meshing impact decrease. The bulk temperature peaks decrease, and the peaks region move from tooth root and top to the tooth profile central.