Bolted bearing connections are one of the most important connections in some industrial structures, and manufacturers are always looking for a quick calculation model for a safe design. In this context, all the analytical and numerical models reduce the global study to the study of the most critical sector. Therefore, the main inputs for these models are the maximal equivalent contact load and the corresponding contact angle. Thus, a load distribution calculation model that takes all the important parameters, such as the stiffness of the supporting structure and the variation in the contact angle, into consideration is needed. This paper presents a 3D finite element (FE) simplified analysis of load distribution and contact angle variation in a slewing ball bearing. The key element of this methodology, which is based on the Hertz theory, is modeling the rolling elements under compression by nonlinear traction springs between the centers of curvature of the raceways. The contact zones are modeled by rigid shells to avoid numerical singularities. Each raceway curvature center is coupled to the corresponding contact zone by rigid shells. The main contribution of this method is not only the evaluation of the contact loads with a relatively reduced calculation time but also the variation in the contact angle from the deformed coordinates of the curvature centers. Results are presented for several loading cases: axial loading, turnover moment, and a combined loading of axial force and turnover moment. The influence of the most important parameters such as the contact angle, the stiffness of the bearings, and the supporting structure is discussed. Finally, a preliminary experimental validation is conducted on a standard ball bearing. The results presented in this paper seem encouraging. The FE study shows an important influence of several parameters and a good correlation with experimental results. Consequently, this model can be extended to other types of slewing bearings such as roller bearings. Moreover, it can be implemented in complex industrial structures such as cranes and lifting devices to determine the corresponding load distributions and contact angles and, consequently, the most critical sector.

3D Simplified Finite Elements Analysis of Load and Contact Angle in a Slewing Ball Bearing

Failure prediction, monitoring and diagnosis methods for slewing bearings of large-scale wind turbine: A review

Computational model for calculation of static capacity and lifetime of large slewing bearing's raceway

A catalogue capacity of slewing bearings

An analysis of double arched ball bearing, which considers centrifugal forces and gyroscopic effects, is performed. Based on operating conditions of a five DOF inner ring and Coulomb friction model, the conventional bearing theory is extended from two to three or four-contact points. The commonly used control criterion of ball bearing by the inner or outer raceway is debatable and is known to fit with difficulty with experimental data. In addition, when more than two-contact points are involved, it becomes obsolete. The paper presents a mathematical model to describe the complex ball bearing internal kinematics under the effect of the external working conditions. Lubricant thickness is taken into account in geometrical equations and the nonlinear system of this quasistatic model is solved by a Newton-Raphson method. The model is first validated through comparisons with published data for conventional or single arched ball bearings. Results are also compared to those provided by the commercial software RBL4 . The analysis of a double arched ball bearing is finally performed and the complex motion of the ball highlighted.

Ball Motion and Sliding Friction in a Four-Contact-Point Ball Bearing

Load distribution in a four contact-point slewing bearing

This paper proposes a procedure,for obtaining the load distribution in a four contact-point slewing bearing considering the effect of the structure's elasticity. The uneven stiffness of the rings and the supporting structures creates a variation with respect to the results obtained with a rigid model. It is necessary to evaluate the effect of the elasticity on the increase in the contact forces in order to be able to design the slewing bearing and the structures involved in the connection. Depending on the shape of the structures, the contact force value obtained on the most loaded rolling element is different. The evaluation of this maximum force at extreme loads is essential to design the structures joined to the bearing rings. The new elastic model presented in this paper is highly nonlinear so iterative loops are needed in order to obtain a satisfactory solution. At the same time a finite element model (FEM) has been created for the global model, having also represented the rolling elements and their contact with the raceways. The results obtained using the FEM have been correlated with the results of the new procedure.

Jorge Damian

Papers

Load distribution in a four contact-point slewing bearing

Design of Four Contact-Point Slewing Bearing With a New Load Distribution Procedure to Account for Structural Stiffness