Study On Design Theory And CNC Manufacturing Method Of The Concave Convex Arc Line Gear

Gear is a kind of important basic component of mechanical products.Its history can be traced back to the BC.The real popularity of gear began with the development of its processing technology.The commonly used processing methods for gear are the generative method and the profiling method.The development of processing methods has also promoted the development of gear design theory.The line gear is a novel gear used in the micro-transmission field in previous research.This dissertation is to extend the line gear to the field of conventional power transmission with medium and low power(500w~5kw).The main content relates to design theory and processing methods of a new type of line gear proposed.This is of great significance to the development of design theory and application for the line gear.In this dissertation,the concave convex arc line gear is proposed and studied,which is suitable for the field of conventional power transmission of small and medium size(normally,20~200mm).First,the design theory of the concave convex arc line gear was established.Then,the general CNC machining method for the concave convex arc line gear based on the four-axis CNC machining center was studied.In order to improve the production efficiency and decrease the processing cost,further studies focused on the special CNC milling method for the concave convex line gear,which provides the theoretical basis for the design of the special CNC machine tool for the concave convex line gear.Finally,an existing CNC machine tool was reconstructed,and samples of the concave convex line gear were processed and kinematic experiments were performed.It was verified that the special CNC machining method proposed in this paper was correct,and the modified machine tool could achieve the expected machining process.In details,the main works of this dissertation covers the following aspects:1.The design theory of the concave convex arc line gear was proposed.According to the meshing theory of the line gear,the equations of the driving and driven contact curves and the tooth thickness auxiliary curves of the concave convex arc line gear were deduced,as well as the equations of the tooth profile of the concave convex arc line gear,and the parameterized design formulae of the concave convex arc line gear were derived.And through the use of assembly and kinematics simulation of Pro / E software,examples of the concave convex arc line gears were designed.Through the simulation of kinematics experiments,the correctness of parameterized design formulae for the concave convex arc line gears was verified.2.The general CNC machining method of the concave convex arc line gear was studied.Through the research on the existing general numerical control technology,the feasibility of using common numerical control technology to process the concave convex arc line gear was analyzed.A general CNC machining method of the concave convex arc line gear was proposed,and samples of the concave convex arc line gear samples were successfully processed with this method.3.The special CNC machining method for the convex concave arc line gear was proposed.According to the meshing principle of the concave convex arc line gear,the special CNC machining method of the concave convex arc line gear was proposed by considering of the structure characteristics of the driving and driven line gears.4.A special CNC milling machine tool for the convex concave arc line gear was studied and rebuilt.According to the special CNC machining method for the convex concave arc line gear proposed,the structure scheme of vertical special CNC machine tool and the structure scheme of horizontal special CNC machine tool were designed.Considering the profile features of the convex concave arc line gear,the design method of the profile of the milling cutter for the convex concave arc line gear was given.Utilizing the existing technical conditions,the existing four-axis vertical machining center was rebuilt according to the vertical special CNC machine tool structure scheme.The samples of the convex concave arc line gear were processed by the rebuilt machine tool.Finally,the feasibility and rationality of the design of CNC machine tool for the convex concave arc line gear is verified through the comparison of machining time consumption,motion simulation and roughness test.