Study of the superfinishing process applied to ball bearing rings.

摘要

Superfinishing is a process that induces a vibratory rubbing action of the abrasive stone with respect to the workpiece. The process involves high speed oscillation of the tool, which removes material by contacting a rotating workpiece. When applied to rolling-element bearing surfaces, the process is claimed to enhance wear resistance and increase fatigue life. Although not used primarily for stock removal, superfinishing also corrects size and shape variations, improves roundness, and provides better blending of profile radii.; The research presented in this dissertation is focused on the superfinishing process as applied to ball bearing rings. Both experimental analysis and modeling and simulation of the process were performed. The following stages were accomplished: (1) Background research on the superfinishing process; (2) Experimental analysis of the process, covering multiple output parameters, both for the abrasive stone and the process; (3) Based on the results of the previous stage, adjustments and modifications of the process were made; (4) A second experimental stage, analyzing the modifications made at stage 3 and narrowing the input variables and output parameters according to the findings at stage 1; (5) Geometric analysis of the contact between the tool—superfinishing stone, and the workpiece—ball bearing ring; (6) Modeling of the abrasive stone, bearing ring and their contact; (7) Simulation of the process by modeling it as sliding wear contact using specialized FEM software.; The simulation focused on the wear evolution of the stone and bearing ring, more precisely the wear patterns on the stone's active surface and the depth of cut on the bearing ring's ball track. The stages of the simulation, which are going to be detailed further, are: (1) Develop a theoretical basis for the local contact wear of two bodies; (2) Develop the simulation algorithm; (3) Selection of the main simulation features and parameters; (4) Analysis of the simulation output data.; The major improvements in the process efficiency resulting from the experimental work are: (1) The required surface roughness can be achieved in a one-step process; (2) The number of consumed abrasive stones is reduced; (3) The productivity can be almost doubled; (4) The idle times for changing the abrasive stone are drastically reduced.; The very consistent output obtained from the simulation model, recommends it for further use in the following directions: (1) Optimization of the stone geometry; (2) Optimization of the process kinematics.