Investigation On Dynamics Simulation Of New CVT Based On Virtual Prototype Technology

The continuously variable transmission(CVT) is widely used in automotive filed, because it has excellent performances, such as simple and convenient operation, smooth and steady shift, comfortable use and economic fuel consumption. As the car ownership is growing explosively, the environmental and resource problems induced by automobile fuel consumption and emissions seem to be severe. Thus, it has great significance to investigate CVT with good fuel economy and puts it into application. Recently, the research and development of CVT have become one of research highlights in automotive filed, and all kinds of CVTs have successively been presented by scholars at home and abroad. After the characteristics of the existing CVTs are analyzed and summarized, a new kind of CVT which is based on the half-torus CVT—ball type traction continuously-variable-transmission(BVT) is proposed by our research group.BVT is mainly composed of the driving wheel disc, driven wheel disc, transition wheel, input shaft and speed governing device. In this system, the torque between the driving wheel disc, driven wheel disc and transition wheel is transferred by the tractive force of lubricating oil at contact point. The position of contact point is changed by rotating of transition wheel through a speed governing device, thus achieving the change of transmission ratio.This paper introduces the working principle and transmission mechanism of BVT, the speed ratio relationship is deduced. For two kinds of lubricating oils, the thickness of oil film between the driving wheel disc, driven wheel disc and transition wheel is calculated. Then, the dynamic equation sets of drive system in BVT are derived, which can provide a theoretical basis for dynamic simulation.In addition,the basic theory and calculation method of rigid flexible coupling dynamics and multi-rigid body dynamics are introduced.Then, the strength of key components for BVT is analyzed by computer-aided design, virtual prototype technology and finite element method. The 3-D model and assembly model of drive system in BVT are first built by using Solid Works. Then, they are imported into software ADAMS to perform the analysis of pure rigid body and rigid-flexible coupling of dynamic virtual prototype. The obtained data are compared with theoretical values to verify the reasonability of the working principle of BVT. Furthermore, the load spectrum of contact force which is used in the finite element analysis is obtained. Final, the contact analysis between driving and driven wheel discs is accomplished.According to the calculation results, the laws of motion of BVT under various working conditions are basically consistent with the theoretical analysis. The key components are able to meet the requirements of strength and stiffness. Thus, the design of BVT is reasonable.