The Study On Key Techniques Of High Speed Coordinated Number Controlled Crankshaft Grinding

Usually, crank have to be grinded using several positioning and clamping operations because of the differences in axes orientations of the main journal and the connecting rod journal. In the operation, there are many problems such as relatively excessive errors of positioning and clamping, low productivity, large investment of equipment and workshops, long period in the adjustment of the machine tool and fixtures and poor surface finish of the ground part etc. From analyzing the mentioned shortcomings, a new grinding principle named coordinated grinding is studied, which allows both connecting rod journal and main journal of the crank to be grinded in only one positioning and clamping operation. Theory of coordinate grinding and some key techniques in the realization and application of this new method are focused on in this paper.This article analyzes the motion specialties of crank connecting rod journal coordinated grinding, finds the necessity of variant velocity motion of crank. In order to get high grinding precision and fine surface quality, the motion model must bases on constant linear velocity for the crank connecting rod journal grinding. The constant linear velocity is used to guarantee the surface quality of crank connecting rod and the constant removal rate guarantees the precision. This paper predigests the motion model of constant linear velocity crank connecting rod journal grinding and makes the model to be easy to calculate. Then it analyzes the error due to predigested model comparing with original model.Grinding force is the key reason which influences precision about crank grinding. According to specialties of crank coordinated grinding, this article contrasted analyzes two kind of calculate formula; chooses one of them which is more suitable to calculate grinding force of crank coordinated grinding. Then it builds the dynamics model of wheel slide relate to grinding force and calculates the acceleration of wheel slide.This article discusses the main reasons which influence the precision and surface quality of crank connecting rod journal coordinated grinding and the relative solutions to improve the precision and surface quality of crank connecting rod journal coordinated grinding. Then it analyzes the rule of influence about the precision and surface quality of crank connecting rod journal due to main error sources, according to theory of error compensation; it builds the relative error compensation model.According to required capacity of wheel slide motion system, which can satisfy high speed coordinated grinding. This article analyzes two kinds of wheel slide drive mode. Due to specialties of each drive mode and required capacity of wheel slide motion system, it chooses linear motor as the drive mode of wheel slide motion system.