Research On Error Analysis And Coordinate Measurement Method Of Limacon Gear

Limacon gear is a kind of non-circular gears which pitch curve is changed by cosine function, and it is widely used in many industrial and agricultural machines like rice transplanter, continuous casting mechanism in the mould, because of its advantages: transmission with variable ratio, compact structure, efficient and stable transmission. In real application, there is a high requirement to this kind of gear,so it is necessary to make a further research on its accuracy control and error measurement. Based on it, took limacon gear as the research object, the machining error and measurement of limacon gear were discussed from two sides as the tooth profile design and gear hobbing error.Firstly, the machining error of limacon gear was analyzed according to the basic error theory of cylindrical gear, and the influence of fabrication error like machine, cutter and gear blank on machining gear was introduced from the following four sides as the accuracy and statistics of non-circular gear, uniformity of load distribution and gear backlash. Error detection projects of cylindrical gear were referred for summarizing the error detection projects of limacon gear.Secondly, each tooth profile of limacon gear was equal to the cylindrical gear with different tooth number according to the theory of conversion method of tooth profile, its model was built in three-dimensional drawing software, and its entity was machined on CNC hobber. Besides, the problem of data sample method of coordinate measuring machine and route planning of measuring points were analyzed, which lays the foundation of the following tooth profile data measuring.Finally, the mathematical models of detected error terms of limacon gear were built by involute normal line method, the data that got by the coordinate measuring machine were inserted in each error term and its results were solved. In order to improve the machining and detecting accuracy of limacon gear, error compensation and correction were done to gear’s error terms, which could improve the working performance of limacon gear in its mechanical transmission system effectively.According to the above research work, the error measuring items of limacon gear were built systematically, which provide reference for the intensive study of limacon gear’s error control and its formulating of accuracy class.