Spherical surface generation mechanism in the grinding of balls for ultraprecision ball bearings

Abstract

Ultraprecision ball bearings are necessary for high-precision machines and/or high-speed machines since the vibration caused by ball bearings determines the precision of machines as a whole and may make high-speed machines fail to work. To produce ultraprecision ball bearings, it is necessary to clarify spherical surface generation mechanism in the grinding of balls. This paper is the first attempt to investigate the contact trace distribution on the ball surface, which is crucial to spherical surface generation. The kinematic analysis of the contact trace shows that the contact trace is a fixed circle on the ball surface and the contact points are not uniformly distributed on the ball surface. Experimental observation of the contact trace was also carried out. The observation is in good agreement with the analysis. Suggestions on how to distribute the contact trace over the whole ball surface and therefore to improve the precision of balls are given.

Lapping of ultra-precision ball surfaces. Part I. Concentric V-groove lapping system

“…4 that for pure rolling at the contact point of C, the ball-spin direction of b is equal to 15.798, which is a larger value than bZ13.48 obtained by Zhang and Nakajima [13] from experimental observation of the contact track. This discrepancy is believed to result mainly from the micro-slip, where the spin angle of b decreases with increasing slip ratio (S A ), as shown in Fig.…”

“…It should be noted that when the effect of the ball circulation angular speed on the ball motion is neglected in Eqs. (7) and (8) by Zhang and Nakajima [13], the spin direction of b is equal to 34.38, which is a much higher b.…”

“…Note that, in the past [13,14], the effect of the ball circulation angular speed on the ball motion is neglected. Hence, they used R g instead of R o or R i in Eqs.…”

“…To compare the experimental results obtained by Zhang and Nakajima [13] with the predictions of this analysis, the typical lapping condition is investigated for the case of q 1 Z q 2 ZqZ458, R b Z6.4 mm, R b Z16 mm, and U p Z83.78 rad/ s. It is seen from Fig. 4 that for pure rolling at the contact point of C, the ball-spin direction of b is equal to 15.798, which is a larger value than bZ13.48 obtained by Zhang and Nakajima [13] from experimental observation of the contact track.…”

“…A series papers have been published on this method [9][10][11][12]. To understand the spherical surface generation mechanism, Zhang and Nakajima [13] are the first attempt to analyze the lapping tracks in terms of the kinematics of the ball lapping process. Their theoretical and experimental results show that the contact trace was a fixed circle for the concentric V-groove lapping mechanism, thus, it is impossible to generate a spherical surface.…”