Simulation of Constant-Volume Removal Rate Machining of Middle-Convex and Varying Ellipse Piston

Yanwei Xu,Tancheng Xie,Yinhao Wang,Qiang Guo

doi:10.1155/2021/5363992

Abstract

One kind of constant-volume removal rate machining method of the middle-convex and varying ellipse piston is proposed in this paper. By analyzing the structure and movement relationship of the middle-convex and varying ellipse piston machine, the NC machining model is built. And, the constant-volume removal rate machining model is also built by superposing the variable rotation satisfying the dynamic performance constraints on the uniform rotation of the spindle of the CNC piston lathe. Then, the instantaneous position parameters of each axis of the CNC piston lathe are obtained and turned into NC code. The functional feasibility of the method finally is verified by simulation machining.

Highlights

In the reciprocating process of crankshaft output torque, the piston transmits the gas pressure in the cylinder to this process through the piston pin and connecting rod, but the clearance between the piston and the cylinder sleeve should be as small and uniform as possible to prevent the piston from being “roughened” or “bitten” in the cylinder
A wedge-shaped oil gap is formed between the middle-convex skirt of the piston and the cylinder wall, which ensures the good lubrication of the piston and reduces the wear of parts
Many scholars have deeply studied the machining method of middle-convex and varying ellipse piston [2–12]. ese achievements have effectively promoted the progress of machining technology of middle-convex and varying ellipse piston, but the noncircular section machining technology of piston skirt studied by these achievements is basically based on numerical control turning method

Summary

Introduction

In the reciprocating process of crankshaft output torque, the piston transmits the gas pressure in the cylinder to this process through the piston pin and connecting rod, but the clearance between the piston and the cylinder sleeve should be as small and uniform as possible to prevent the piston from being “roughened” or “bitten” in the cylinder. E rotation speed of the main shaft of the machine tool is continuously regulated, and the material removal rate and cutting force of the middle-convex and varying ellipse piston skirt are basically constant. In the process of fitting the discrete points of middle-convex profile in piston skirt shown, N discrete points are put into the XOZ coordinate system in which the X-axis is parallel to the piston cross section and the Z-axis is the piston axis (X represents the long half-axis of elliptical cross section and Z represents the piston skirt height). E process of turning skirt profile of middle-convex and varying ellipse piston by motion synthesis method can be divided into two independent motions: (1) the motion of tool relative to workpiece forming middle-convex profile is Numerical control device

Work piece

Skirt height H

Serial number