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

Abstract

Cageless ball bearings with discrete grooves in the outer raceway enable the dispersion of rolling elements. Once worn, the discrete groove can cause the rolling element to discretely fail. This paper presents the discrete element method to investigate the wear of discrete grooves in cageless bearings from the standpoint of bond fracture. In conjunction with the structural characteristics of bearing races with discrete slots, we propose a hexagonal close-spaced spherical particle arrangement, in which the discrete slots are discretized into particles of the same size that are connected by bonds. The contact model and contact force equation between the rolling elements and the aggregate elements are established, and the external force on the aggregate elements is calculated. Under the influence of an external force and the arrangement of particles in the aggregate element, the internal force transfer equation of different layers and different particles is derived, and the internal force of the particles in the aggregate unit is calculated. In accordance with Hertz–Mindline theory, the bonding model of discrete groove particles is established, the size of the particle shedding cohesive force during bond fracture is determined, and the wear degree of discrete grooves is characterized by comparing the cohesive force and internal force. Numerical solutions and wear tests are combined. Bond fracture can accurately characterize the wear of discrete grooves. This approach offers theoretical guidance for cageless bearing design.

Characterization of Microscopic Damage Evolution of Functional Groove in Cageless Bearings

“…Bonding between the two particles due to contact, here, can become the formation of the connection bond in the process of bearing operation. The particles are subjected to the external force generated when the rolling element squeezes the surface of the functional groove, and the particles on the surface of the functional groove transform the external force into the internal force of the internal particle contact and transfer it to each layer on the particle level [31]. The change in the amount of overlap generated between the particles leads to a change in the contact force, and the area of contact and the magnitude of the contact force directly affects the change in the interparticle bonding force.…”