Design Method Of High-Order&Multi-segment Modified Elliptical Gears And Their Manufacturing Theories

Non-circular gears synthesize the advantages of both cylindrical gears and cam mechanisms, and can offer a combination of high output power and excellent level accuracy with a continuously variable transmission. Moreover, they can be employed to achieve non-circular trajectories precisely. It is therefore difficult to machining a non-circular gear accurately for the reason that they have a wide range of items and a variety of shapes, and are also complicated in design and calculation of gear pairs. Especially, the (angular) velocity and the (angular) acceleration of linkage axes vary intensively follow time in hobbing or shaping. Hence, it is difficult to manufacture for non-circular gears, and the precision of which is difficult to ensure. In order to take advantage of non-circular gears in transmission and meet to the requirements of numerous manufacturing in reality, the design of non-circular gears should be described as a unified form and some manufacturing technologies with high accuracy and high efficiency should be studied, which are of great value.Families of elliptic gears with closed pitch curve have been described by a kind of high-order & multi-segment modified elliptic ones. The transmitting mechanisms of the high-order & multi-segment modified elliptic gear pairs have been explored, and then the drive characteristic of which have been analyzed. What have implemented achieved the goal of standardized design, which can be widely adopted and applied by peers. In view of the technique states that non-circular gears had been universally machined by inefficient wire-electrode cutting, some linkage schemes of hobbing and shaping for non-circular gears and their mathematical models have been optimized and selected. Therefor, complete manufacture theories for non-circular gears have been built. This article focuses on diagonal hobbing method for non-circular gears and manufactures theories for non-circular helical gears. The goal of machining non-circular (helical) gears has been obtained with high efficiency, high precision and low cost.Based on the analysis and summary of the design methods for non-uniform speed transmissions and the manufacturing technologies for non-circular gears at home and abroad, the design method and characteristics of high-order & multi-segment modified elliptic gears have been studied intensively by means of combining theoretical analyses, numerical simulations and experiments. Moreover, the hobbing and shaping methods for non-circular gears with free pitch curves, including high-order & multi-segment modified elliptic gears, have been in-depth researched. The main research works and achievements are as follows:1) The design theories for the transmission of the families of elliptic gears with closed pitch curve have been researched. Practicable design methods for transmission of high-order elliptic gears, two-segment modified elliptic gears and high-order & two-segment modified elliptic gears have been provided according to the maximum transmission ratio and minimum one in practical application. Especially, transmission theories of families of elliptic helical gears and the families of internal elliptic gears have been researched. On this foundation, the uniform mathematical expression for the families of elliptic gears with closed pitch curve, namely high-order & multi-segment modified elliptic gears, has been presented. The design methods and the performance characteristics of gear pairs have also been researched.2) The CAD system and the virtual machining methods for high-order & multi-segment modified elliptic gears have been investigated. The CAD system that has multiple functions for high-order & multi-segment modified elliptic gears has been developed with the hybrid programming of Matlab and VBA. Moreover, some virtual machining methods of hobbing and shaping for high-order & multi-segment modified elliptic gears have been researched.3) Multi-strategy hobbing technologies for non-circular helical gears have been researched and analyzed. The practical linkage models including four-axis simultaneously with diagonal hobbing, five-axis simultaneously with non-diagonal hobbing, five-axis simultaneously with diagonal hobbing, and six-axis simultaneously with diagonal hobbing have been established separately. Subsequently, optimum hobbing models of them have been identified. Finally, the application methods of the two kinds of diagonal hobbing have been provided.4) Shaping technologies of external non-circular gears and internal non-circular ones have been studied. Based on the fundamental linkage model of gear shaping, all adoptable practical linkage models that have the functionalities of shaping non-circular helical gears have been developed successfully. The performances of the linkage models and their schemes have been tested. Eventually, the optimum linkage scheme has been achieved. Therefore, an integrated theory of shaping non-circular gears has been constructed completely.