Analysis of Contact Stress Distribution between Rolling Element and Variable Diameter Raceway of Cageless Bearing

Abstract

The change in contact state between the rolling elements and raceway of a cageless bearing with a variable diameter raceway affect the wear of the bearing, which leads to discrete motion failure of the rolling elements. For this purpose, the contact characteristics as contact form and contact stress between the rolling elements and raceway were determined. A numerical method is proposed to determine the three-dimensional contact stress of a cageless bearing. First, combined with the variable diameter raceway structure characteristics and the motion of rolling elements, the rolling elements and raceway contact stress model was established, and the influence factors of contact stress and the maximum stress distribution were determined. Based on the rolling contact theory, the relative position of the stick-slip region and the tangential stress distribution of the contact area were analyzed. The stress equations for the three-dimensional between rolling elements and variable diameter raceway were obtained by the principle of superposition, and the stress component characteristics of the contact area were numerically simulated. The results show that the main influencing factors of contact stress are: load, structure of variable diameter raceway, spindle speed, friction coefficient µ and the ratio of the stick region and the slip region k. Taking a cageless bearing as an example, the influence of the contact curvature Ri on the contact stress is smaller than that of ri. Increasing ri to make it larger than 1.5 mm and controlling the speed to be lower than 13,950 r/min, the maximum stress appears in the conventional raceway, which is beneficial to alleviate the failure of the variable diameter raceway. There are a slip region and a stick region in the contact area, reducing the friction coefficient µ and increasing the stick-slip coefficient k appropriately can ensure the discrete movement of the rolling elements and reduce the wear of the variable diameter raceway. The error of the stress distribution model is less than 15%, which can predict and characterize the contact stress distribution between the rolling elements and the variable diameter raceway. The theoretical guidance for the development and application of cageless bearings is provided.

Finite Element Analysis for Cylindrical and Balling Bearings Under Static and Dynamic Loads A-review paper

“…Additionally, the increased number of defective rollers and the increase in defect width will make the cage slide and the bearing vibrate more. [3], [4].…”

Stability investigations of cageless ball bearings considering balls and outer rings with variable diameter raceways

“…Based on the superposition principle, the three-dimensional stress equation between the rolling element and the variable diameter raceway is obtained, and the characteristics of the stress components in the contact area are numerically simulated. The results show that the main factors affecting the contact stress are: load, variable diameter raceway structure, spindle speed, friction coefficient m, stick slip ratio k. 14 The aforementioned literature demonstrates that more effort has been invested in the structural optimization design of the new bearing. However, as the number of design variables increases, the complexity of the problem increases, and the structural optimization design direction for the new cage-free ball bearing must be determined in greater detail.…”

“…The results show that the main factors affecting the contact stress are: load, variable diameter raceway structure, spindle speed, friction coefficient µ , stick slip ratio k . 14…”

Characterization of Bond Fracture in Discrete Groove Wear of Cageless Ball Bearings

“…Collisions among rolling elements in cageless bearings occur due to the absence of a cage. To achieve the stability of cageless bearings, Zhao et al proposed a method of setting a reduced collision groove in the outer raceway to make the rolling elements discrete [ 1 , 2 ]. However, the constant contact between the rolling elements and the discrete groove will lead to wear of the discrete groove, which will affect the discrete rolling elements [ 3 ].…”