An optimum preload method for machine tool spindle ball bearings

Abstract

To provide a suitable rotation rate for different machining processes, a single machine tool spindle should work over a wide range of speeds. This study considered the effects of speed on dynamic behaviour of ball bearings and combined the fatigue life model and ball bearing internal load distribution model to determine the appropriate preload. First, the influence of speed on internal load distribution and ball bearing contact angles was analysed. The preload was calculated using a ball bearing internal load distribution model. Next, assuming constant bearing fatigue life, the theoretical preload curves were determined using the fatigue life model by changing the reliability factor. Finally, at low speeds, the maximum designed preload (design value) was set as the initial preload. With the increase in speed, the optimum preload was hierarchically obtained within the internal region between the theoretical preload curves. An experimental test rig for the optimum preload of ball bearings, which can automatically adjust the preload, was developed. The proposed method for determining the optimum preload was verified using the measured performance indicators, including the temperature, motor currents, and vibration of ball bearings. The results showed that the optimum preload suggestion made the test ball bearings exhibit excellent behaviour.

Research Development of Preload Technology on Angular Contact Ball Bearing of High Speed Spindle: A Review

“…Xu [46] employed the power spectrum density method to study the frequency response of the spindle under different preload and rotation speed, predicted the connection between frequency characteristics and the preload. Xu [47] indicated that motor current value, bearing vibration, temperature rise and preload varied with rotation speed when the constant pressure preload was applied.…”

“…Jones proposed a formula for calculating the minimum preload based on gyro torque prevention. Xu [47] believed the correlation between maximum preload and rotation speed could be determined if the bearing service life and reliability factors have been obtained. Jiang [49] analyzed the minimum preload of ACBB under two kinds of preload manners, discovered the diversities existed in speed-minimum preload reaction relating to steel ball and ceramic ball: the minimum preload increased with rotation speed in steel ball (which was exactly dissimilar as the general recognition that high speed bearing should be lightly preloaded) while didn't increase with rotation speed in ceramic ball.…”

“…Qiu [58] designed a dynamic test rig to determine the minimum bearing preload at different speed. By combining the bearing fatigue life model and the internal stress distribution model, Xu [47] optimized the preload based on multi-parameter criteria with respect to bearing life reliability condition, analyzed the rotation influence on internal stress distribution and contact angle variation, obtained the optimal preload by adjusting the reliability of the fatigue life model. Dong [54] proposed a complete calculation method to obtain the optimal preload, with impact factors such as bearing stiffness, temperature rise, fatigue life and ball sliding considered.…”

Influence of Housing Material and Geometry on Thermal Stability of Threaded Spindle Bearing Assembly

“…Dong et al in their work [9] present a method for determining the optimal bearing bias in a wide range of speeds that is applicable in the design of machine tool spindles. In [10,11] authors test the influence of velocity on the dynamic behavior of a ball bearing and determine the optimum bearing bias using a combination of fatigue model and internal load distribution. Zhang et al provide a comparative model that analyses the stiffness of angular contact ball bearings that are preloaded by different preload mechanisms [12].…”

The effects of zinc hydroxystannate/boron nitride hybrids and aluminum diethylphosphinate on flame retardancy and smoke suppression of styrene–butadiene rubber composites

“…They have a layered structure and are widely used for flame retardants, 11 heat conduction, 12 and semiconductors. 13 Common two-dimensional materials include graphene, 14 double hydroxide, 15 carbon nitride, and boron nitride (BN), 16 As a inorganic two-dimensional nanomaterials, BN is widely used in various fields due to its excellent physical and chemical properties. [17][18][19] Many studies have shown that the addition of BN nanosheets to polymers can effectively improve their flame retardancy, thanks to their high thermal stability and physical barrier effect.…”