The Face Hobbing Theory And Experiments Of Hypoid Gear

With the characteristics of continuous indexing and both sides of tooth manufactured at one time,the face hobbing method of hypoid gear is featured with high efficiency and dry cutting obtained easily.So,it is used more and more widely in mass production nowadays.In the past,there were the problems of insufficient basic research and the key information strictly confidential,as a further consequence,a completed set of face hobbing technology and equipments have not been developed yet in China.Though qualified productions can be manufactured by importing foreign technology,there is no real benefit for improving Chinese face hobbing technology.Besides,because of the monopoly position of other countries,the high price of imported machine and inconvenience of maintaining,this method can not be popularized easily in China.In order to meet the need of face hobbing method in Chinese car industry,some crucial basic theories,such as the tooth form generating principle?the geometric design &calculation of tooth blank?the accurate control of tooth contact characteristics?the calculation of machine setting parameters?the motion control of the CNC hypoid generator and the measurement& modification of tooth form deviation,are systematically studied in this paper.A unified model for the calculation of hypoid gear pitch cone parameters during the process of Spiroflex&Spirac face hobbing is established.A method for machine setting parameters calculation for face hobbing is proposed that can arbitrarily define a contact position in gear tooth surface and take control of the tooth contact status of both sides at the same time.A model for the calculation of time-varying mesh stiffness?transmission error?meshing impact and meshing internal force of hypoid gear is established with the Static and dynamic finite element methods.And the meshing internal forces are analyzed under various contact status.With this method,the tooth contact characteristics were optimized.A 6-axis motion control model of CNC hypoid generator was proposed by taking cutter axis vector as control objectives to transform the attitude of whole cradle-type generator.Based on Siemens 840 Dsl CNC system,the control system of CNC hypoid generator was designed,and the face hobbing NC software was developed.Based on the CNC motion control model,the tooth form equation of face hobbing hypoid gear is deducted.The tooth pitch error and tooth form deviation measurements were realized on the domestic gear measuring center.Using the measurement results,tooth form deviation automatic correction method was studied based optimization method with tooth root deviation constraint.Finally,machining simulation,gear cutting,measuring and rolling test experimental were applied to verify the above theories and methods.In a word,a face hobbing closed-loop manufacturing process is established in this paper.At present,the main achievements from this paper are applied in CNC hypoid generators by Tianjin No.1 Machine Tool Works,providing solid theory basic for researchers to develop and apply the face hobbing processing equipments as well as enhancing our capability of independent innovation in this aspect.