Variable Convex Oval Piston Cnc Lathes

Piston is one of the key parts of internal combustion engines, which directly determines the work performance of internal combustion engines. Middle-convex and varying ellipse piston turning is a special noncircular cross section, and its special molding surface brings difficulty for its design and processing. This becomes an important task in the researching domain of the piston.According to China's processing status of the piston, this paper presents a design of the piston CNC lathe. The NC system is an open double CPUs architecture based on PMAC motion controller and industry PC. X-axis feed movement using servo motor and linear motor double-driven mechanism, realizing loop control through raster feedback; Z-axis feed motion with servo motor and ball screw drive; Adopting servo control, Spindle coordinates the turn of the spindle shaft angle and X-axis radial displacement by TUBRO PMAC controller; The linkage of X-axis and Z-axis can realize the piston convex surface processing. In contrast with the traditional hard profiling method, the method has the advantages of good flexibility, high processing efficiency and high degree of accuracy. According to the middle-convex and varying ellipse piston turning's processing characteristics, we designed overall structure of the CNC machine for a piston, and using Pro/E to establish machine's solid model. Various transmissions of machine tools have undertaken a major design and calibration, while chosen the motor to match with. The key of pistons CNC lathe is X-axis feed mechanism design. On this premise conditions, a linear motor actuator driven tool holder and related mechanism was designed, and its model was given in the view of system dynamics. At last, we design the controller of control system for servo knife holder.The system is an open double CPUs architecture based on PMAC and industry PC. TURBO PMAC's PCOMM32 is called by VC++ in the Windows platform, which developed numerical system management software modules.At last, through the characteristics of middle-convex and varying ellipse piston turning, we identified two kinds of piston CNC turning methods. After turning a comparison experiment, we choose the way which based on TURBO PMAC's movements control of the turning axis. We make the piston turning experiments by date which is provided from piston manufacturer.The conclusions studied above is specially present for middle-convex and varying ellipse piston turning, what's more, it also can be referenced for other noncircular cross section works. It provides favorable foundation for more research of the noncircular cross section turning.