Dissertation Submitted For The Application Of Master’s Degree Of Engineering

Automobile engine piston is the core component in engine system. The engine piston is working in worst condition of one of all parts. To enhance the comprehensive performance of the piston and improve the effective power of the engine, reducing emissions, noise and fuel consumption, is one of the effective ways of increasing demand, reliable work performance on automobile engine power, environmental protection and economic performance.Middle bulged varying ellipse piston is currently the most widely used in engine piston. This kind of piston type based on the complexity and difficulty to ensure machining accuracy, ordinary lathe can not realize the processing the special-shaped piston, around Middle-convex and varying ellipse piston lathe is transformed to Machining of NC, this paper research as follows:(1) The Middle-convex and varying ellipse piston skirt profile formation mechanism is analyzed, and the profile is expressed by the mathematical method, the basic Turning Machining principle of Middle-convex and varying ellipse piston is expounded, and introduces the general lathe numerical control transformation, achieve Middle-convex and varying ellipse piston Machining scheme.(2)NC transformation is completed for common lathe for mechanical structure of existing CA4160parts, without changing the spindle system, motor spindle and feed movement separates, and complete control of the spindle rotation angle position by photoelectric encoder, designs the longitudinal, transverse long stroke feeding system and high frequency and large stroke micro feed system, and position control of the feeding system is studied.(3) The existing ordinary lathe added the parts of CNC system, CNC system using built-in type, independent type PLC in CNC system complete the sequence control of CNC system, I/O module and a communication system are designed.(4) Through the operating system on the PC, debugging and experiment of convex lathe processing is finished by using the software to realize the transformation of the variable Ellipse Piston, the test shows that, the research of the NC transformation process Middle-convex and varying ellipse piston is feasible, reasonable.