Mathematical Model and Machining Method for Spiral Flute Rake Faces of Hourglass Worm Gear Hob  

作　　者：YANG Jie LI Haitao RUI Chengjie HUANG Yi ZHANG Xiaodi 

机构地区：[1]College of Engineering,China Agricultural University,Beijing 100083,P.R.China [2]Key Laboratory of Optimal Design of Modern Agricultural Equipment in Beijing,China Agricultural University,Beijing 100083,P.R.China [3]Beijing Kuiente Technology Co,Ltd,Beijing 100043,P.R.China

出　　处：《Transactions of Nanjing University of Aeronautics and Astronautics》2019年第3期401-412,共12页南京航空航天大学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China (No. 51475460)

摘　　要：To improve the cutting performance of an hourglass worm gear hob and the accuracy of the resulting worm gear,the rake angles of the teeth on the pitch circle should be reduced.A method of forming the spiral flutes by using a variable transmission ratio was developed.This method ensures that the rake angles on the indexing torus of each tooth are approximately 0°.Based on the gear meshing theory and the hourglass worm forming method,the discretization mathematical model of the rake face of a planar double enveloping worm gear hob was established by using cylindrical generating surface,and the feed parameters for machining the rake face for a variable transmission ratio were obtained.The spiral flute was simulated and the hob was machined on a four axis CNC milling machine.A contourgraph was used to measure the rake angle.The measurement results showed that the proposed method can reduce the absolute value of the rake angle on both sides of the cutting teeth,which can be used for machining the spiral flute rake face of an hourglass worm gear hob.To improve the cutting performance of an hourglass worm gear hob and the accuracy of the resulting worm gear,the rake angles of the teeth on the pitch circle should be reduced. A method of forming the spiral flutes by using a variable transmission ratio was developed. This method ensures that the rake angles on the indexing torus of each tooth are approximately 0°. Based on the gear meshing theory and the hourglass worm forming method,the discretization mathematical model of the rake face of a planar double-enveloping worm gear hob was established by using cylindrical generating surface,and the feed parameters for machining the rake face for a variable transmission ratio were obtained. The spiral flute was simulated and the hob was machined on a four-axis CNC milling machine. A contourgraph was used to measure the rake angle. The measurement results showed that the proposed method can reduce the absolute value of the rake angle on both sides of the cutting teeth,which can be used for machining the spiral flute rake face of an hourglass worm gear hob.

关 键 词：HOURGLASS WORM gear HOB cylindrical generating surface SPIRAL FLUTE RAKE face RAKE angle 

分 类 号：TH132.4[机械工程—机械制造及自动化]