An ultra-high-speed centrifugal grinding approach for thin-walled bearing rings

Abstract

Machining deformation of thin-walled bearing rings is difficult to avoid during traditional processing, resulting in an adverse impact on residual stress. Ultra-high-speed centrifugal grinding as a new method may be applied to control finished surface’s residual stress of bearing ring. This paper proposes an ultra-high-speed centrifugal grinding approach for bearing ring. First, a 3D prestress model for bearing ring in the action of inertia and magnetic force was derived by space stress solution to reveal the relationship between prestress and rotating speed. Then, several experiments of prestress and grinding temperature were conducted respectively on ultra-high-speed grinder by using prestress clamping device and clip-on thermocouple temperature sensor. Finally, residual stress, grinding force, surface morphology, grinding temperature, and surface roughness were investigated. A case study shows that circumferential prestress and axial prestress are proportional to the square of palstance. The superficial circumferential prestress, contrary to superficial axial prestress, is tensile stress, which is at least 20 times larger than the axial one. The influence of magnetic force on workpiece prestress is negligible in high rotation speed. Experimental results show that residual tensile stress decreases with increasing prestress, whereas prestress has little impact on grinding force. Moreover, a large prestress produces a deep grinding dent on the finished surface. It is also found that the maximum grinding temperature of the Salomon curve gradually shifts to the lower right with increasing workpiece speed. Low grinding temperature may be achieved in the case of high wheel speed and workpiece speed.