Research On Machining Technology Of High-ratio Hypoid Gears Manufactured By Duplex Helical Method

Gear transmission equipment develops towards the direction of high power density and high efficiency with the rapid development of industry.And High-ratio hypoid gears are applied more and more widely.Compared to the traditional reduction gears,the High-ratio hypoid gears have many advantages,such as more stable transmission,less spatial occupancy and more load suffering.And High-ratio hypoid gears have successfully replaced traditional worm gear and planetary gear.The High-ratio hypoid gears have been applied in many mechatronics products,such as the servo system of numerical control machines and industrial robots.The duplex helical method has more accuracy and more efficiency than five-cut process.However,there are some problems for duplex helical method,such as geometric constraints of gear blank,establishment of model of gear cutting and calculation of machine setting parameters.This paper makes research on the Gleason High-ratio hypoid gears manufactured by duplex helical method to solve the key technical problems.The main research contents of this paper are as follow:1.The keys of design of High-ratio hypoid gears are determinations of gear and pinion's pitch cone and calculations of geometric parameters.Based on the meshing theory of hypoid gear,the paper makes researches on the design of Gleason high-ratio hypoid gears with parallel tooth depth.Geometric constraints of spiral angle,pinion offset,face width and addendum factors are given out.And methods of calculations of geometric parameters are established.2.The mathematical gear cutting models of duplex helical method are established by using local conjugate theory of hypoid gear and spatial vector calculation.Based on the equations of face cone of gear and cutter,the intersection is calculated.The secondary cutting can be avoided when the distance between center of cutter and vertex of intersection is greater than the radius of cutter.Principle of gear meshing and differential geometry are used as the theoretical basis,the calculating methods of machine-tool settings and parameters of cutter for the High-ratio hypoid gears are taken out.3.Based on cutting theory of High-ratio hypoid gears and relative position and relative motion between gear blank and cutter,the tooth surface equations of gear and pinion which manufactured by circular arc blade are calculated.Based on equations,the tooth surfaces are divided into discrete points.And the values of coordinates and normal vector components are calculated.4.And the calculations of high-ratio hypoid gear blank design,machine settings parameters for duplex helical method and calculations of value of discrete point coordinates are programmed by Visual Basic.5.Based on the above researches,a pair of high-ratio hypoid gear which has the gear ratio of 1:120 is designed.Using program to calculate machine settings parameters and making a grinding test for the gear of 1:120.And verifying the correctness of gear blank parameters,machine setting parameters and value of discrete point coordinates by observing tooth contact area and tooth profile error.