The Design And Manufacturing Technology Research Of The Precision Spiral Broach About Internal Gear

Among the methods processing the engine helical gear in the industry, the spiral broach has much high machining accuracy, and people pay more and more attention to processing ability of complex surface. Although spriral broach has the advantage of high strength and firmly cutting ability compared to the common broach, but because of its structural complexity and much higher requirements on the precision, the spiral broach mainly relies on import in our country and the price is very expensive. The processing machine and the process methods take responsibility of limiting the spriral broach development. That is why we should design and manufacture the spiral broach which can achieve the international leading machining accuracy in the existing technology conditions. In this paper some research is done on spriral broach that based on the above content.Firstly, some improvement is made on the disadvantage of the cutting method and a new cutting method that can achieve higher accuracy based on the broaching principle is designed. The corresponding tooth shape is designed based on the cutting method, and the cutting force of the designed tooth is calculated. The distance of the tooth,the size of the let cut groove and so on are designed. This paper also provides the design scheme about the fabricated broach which is popular nowadays.Secondly, by the use of the finite element simulation software, the cutting force,the maximum stress on the tool nose and the cutting heat about different rake angle,different tool orthogonal clearance and the different side clearance is measured. By comparision, the optimal cutting angle is selected. Compared by the theoretical calculation, the result of the simulation calculation is found ture. The intensity of the side cutting teeth which bear larger cutting force is checked and their maximum stress and deformation is made sure whether meet the requirements.Thirdly, the whole process procedure of the spiral broach is formulated and the key processes is analysised in detail. Combining with the forming method that grinds the straight teeth, the problems caused by the changes of the shape of the grinding wheel are solved when grinding the helical gear. a convenient system is designed to calculate the tooth profile error. This system includes the calculation of the inner gear length bar size, the common normal line, the chordal thickness and so on. And by using the existing detection conditions, the current test method is improved and the detection scheme is optimized in this paper, which can measure the spirals error.