Study On The Key Theory Of Cam Manufacturing Quality Controlling And Grinder Design By CNC Method

Camshaft is one of the key parts of automobile engine. In the most domestic factory the traditional method of grinding cam by copying is used widely, this method is of low efficiency, bad precision and lack of flexibility. Nowadays the computer numerical control technology is used generally in the developed countries. The CNC method has the advantage of high efficiency, good quality, and is improved as the main means of manufacturing camshaft.In this paper, the function and shape feature of camshaft is stated. The development general conditions and classified method of camshaft is introduced. The CNC method for camshaft grinding has the advantage of high efficiency, good flexibility, precision and steady quality by compared with copying method. There are three kinds of forming ways when grinding camshaft by CNC method. The mode of work-piece rotating around C axis and grinding-head moving along X axis is of high precision and simple structure. The common quality problems such as bad precision, grinding burning, grinding veins, and their influencing factors are analyzed. The CBN-wheel has remarkable advantage of high grinding efficiency and quality. The specific property of CBN-wheel is analyzed.Primarily, the mathematic model of the center movement of grinding-wheel needs to be built while using CNC technology. According to the rise-range table and relationship of r( θ ), two kinds of mathematic model is deducted to adapt different known conditions, and the first one can be applicable for all kinds of tappet including deviation one, and it is more universal.In the process of grinding camshaft, some quality defects, such as lack of precision, shape errors, and damage the surface quality of cam, appeared easily. The manufacturing quality of camshaft is controlled by analyzing the influence of wheel radius, grinding strength and grinding speed, and the constant grinding speed mathematic model is established to realize the constant grinding quantity.Grinding-head is the key part of CNC cam grinder. The liquid hydrostatic bearing can meet the demand of high precision, high speed and high rigidity because of it's own advantage. According to it's principle and feature, the liquid hydrostatic bearing grinding-head of CNC grinder is researched and designed.