Development of PM Sprocket Combined with Housing Body for Motor-Driven Electric Variable-Valve-Timing Control Systems

摘要

Variable Valve Timing (VVT) Control System is used for almost all new model vehicles, and is generally actuated by hydraulic system. However, recently, due to market demands such as high engine performance, low fuel consumption, and low emission, Motor-Driven Electric VVT is newly developed. This PM Sprocket consists of timing sprocket and housing body. Since this new part has such a complicated shape to satisfy its functions, the initial design considered the sprocket and the housing to be made separately by conventional process and joined by screw bolts. This newly developed housing sprocket is compacted in one single compacting stroke using a CNC Multi-level compacting press developed to produce complicated shapes and to achieve tight dimensional tolerances without a sizing operation.