Design Theory Research Of Tooth Modification Of Spur Bevel Gear

Differential, as a key component of automobile, plays an important role to various performances. It is main part is gear transmission system. So, the gear transmission state will influence the automobile performances directly. In order to reduce noise and vibration of the gear transmission system and improve the stress distribution on tooth face, the modification of spur bevel gear (including: profile modification and axial modification) is studied in this paper by means of finite element method.The involute of spur bevel gear is spherical involute, which is different from the involute of cylindrical gear.For the complicated space structure, the spherical involute can not be obtained directly through 3D software and therefore the plane involute or the three-point arc is often used instead. In this sense, the accuracy of solid modeling can not be guaranteed. To solute this problem, a precision modeling method based on Matlab and SolidWorks is given in this paper. For the model is parameterized, new gear model can be obtained directly only by modifying the parameters, such as pressure angle, teeth, module, sphere radius, etc.Based on the joint technique of SolidWorks-ANSYS-LS-DYNA, the modeling process of finite element model is given in this paper, including the boundary conditions and the constrain method of gears which are in meshing. The simulation information, such as the contact stress and the acceleration, can be obtained by LS-PREPOST, which is used to guide the modification of spur bevel gear.Because of the contact deformations, manufacture and installation tolerances, the base pitches of the meshing gears are not equal, vibration and impact as practical consequences that follows naturally. Therefore, profile modification of spur bevel gear should be used. Dynamic simulation of modified gear pair is operated in this paper. The simulation results show that, meshing impact can be decreased effectively. The necessary of axial modification has been shown through the teeth"end contact"phenomenon. Isometric modification is proposed as a new method of axial modification of spur bevel gear. The contact area is determined by the position and the size of isometric modification. In compared with crowned tooth, it has a wide range of application.