Mechanical model development of rolling bearing-rotor systems: A review

A six-degree-of-freedom model was developed and used to simulate the motion of all elements in a cylindrical roller bearing. Cage instability has been studied as a function of the roller-race and roller-cage pocket clearances for light-load and high-speed conditions. The effects of variation in inner race speed, misalignment, cage asymmetry, and varying size of one of the rollers have been investigated. In addition, three different roller profiles have been used to study their impact on cage dynamics. The results indicate that the cage exhibits stable motion for small values of roller-race and roller-cage pocket clearances. A rise in instability leads to discrete cage-race collisions with high force magnitudes. Race misalignment leads to a rise in instability for small roller-cage pocket clearances since skew control is provided by the sides of the cage pocket. One roller of larger size than the others causes inner race whirl and leads to stable cage motion for small roller-race clearances without any variation in roller-cage pocket clearance. Cage asymmetry and different roller profiles have a negligible impact on cage motion.

Cage Instabilities in Cylindrical Roller Bearings

This bibliography is comprised of approximately 1,600 reference citations related to four problem areas in the mechanics of failure in aerospace structures. The bibliography represents a search of the literature published in the period 1962-1976, the effort being largely limited to documents published in the United States. Listings are subdivided into the four problem areas: Hydrogen Embrittlement; Protective Coatings; Composite Materials; and Nondestructive Evaluation. An author index is included.

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Bibliography of information on mechanics of structural failure (hydrogen embrittlement, protective coatings, composite materials, NDE)

Investigation on heat dissipation characteristic of ball bearing cage and inside cavity at ultra high rotation speed

A model for deep-groove and angular-contact ball bearings was developed to investigate the influence of a flexible cage on bearing dynamics. The cage model introduces flexibility by representing the cage as an ensemble of discrete elements that allow deformation of the fibers connecting the elements. A finite element model of the cage was developed to establish the relationships between the nominal cage properties and those used in the flexible discrete element model. In this investigation, the raceways and balls have six degrees of freedom. The discrete elements comprising the cage each have three degrees of freedom in a cage reference frame. The cage reference frame has five degrees of freedom, enabling three-dimensional motion of the cage ensemble. Newton's laws are used to determine the accelerations of the bearing components, and a fourth-order Runge-Kutta algorithm with constant step size is used to integrate their equations of motion. Comparing results from the dynamic bearing model with flexible and rigid cages reveals the effects of cage flexibility on bearing performance. The cage experiences nearly the same motion and angular velocity in the loading conditions investigated regardless of the cage type. However, a significant reduction in ball-cage pocket forces occurs as a result of modeling the cage as a flexible body. Inclusion of cage flexibility in the model also reduces the time required for the bearing to reach steady-state operation.

A Discrete Element Approach for Modeling Cage Flexibility in Ball Bearing Dynamics Simulations

Gas Turbine Engine Mainshaft Roller Bearing-System Analysis

A General Method for Predicting the Influence of Structural Support Upon Rolling Element Bearing Performance

Dynamic Capacity of Oscillating Rolling Element Bearings

: The objective of this program was to conduct a preliminary analytical investigation of the stress field in a hollow sphere in the vicinity of the contact area. The sphere is subjected to a normal load applied through a flat plate. The elastic contact shape and extent were developed for a load of 1000 lb. applied to a one-inch diameter hollow ball with a 0.08 inch thick wall. (Author)

Analysis of the Elastic Contact of a Hollow Ball with a Flat Plate.

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Discussion: “Dynamic Capacity and Surface Fatigue Life for Spur and Helical Gears” (Coy, J. J., Townsend, D. P., and Zaretsky, E. V., 1976, ASME J. Lubr. Technol., 98, pp. 267–274)

J. H. Rumbarger

Papers

Gas Turbine Engine Mainshaft Roller Bearing-System Analysis

A General Method for Predicting the Influence of Structural Support Upon Rolling Element Bearing Performance

Dynamic Capacity of Oscillating Rolling Element Bearings

Analysis of the Elastic Contact of a Hollow Ball with a Flat Plate.

Discussion: “Dynamic Capacity and Surface Fatigue Life for Spur and Helical Gears” (Coy, J. J., Townsend, D. P., and Zaretsky, E. V., 1976, ASME J. Lubr. Technol., 98, pp. 267–274)