Rolling Bearing Cage Geometry to Prevent Wedge Engagement
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Solution Overview
Problem
Existing rolling bearing cages experience damage due to wedge actions between pockets of different phases and single pockets, caused by the movement of the cage in the radial direction, leading to potential damage to the column portion.
Innovation Solution
The design of the rolling bearing cage incorporates Gothic arch-shaped inner or outer holding portions, with controlled wedge angles between pockets to prevent engagement, ensuring the positive minimum value of wedge angles exceeds the friction coefficient, thereby reducing the force applied and minimizing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cage moves in the radial direction due to self-excited vibration or centrifugal force, then the rolling element may engage with the holding portion in a wedge shape, but this wedge engagement prevents smooth rotation and may damage the column portion
Solution Approach 1:
The holding portion is designed with a curved surface (Gothic arch shape) instead of a straight or flat surface. This curvature ensures that when the cage moves radially, the rolling element contacts the curved surface at an angle that prevents wedge-shaped engagement. The curved geometry transforms the contact mechanics to allow the rolling element to roll smoothly along the arc rather than becoming locked in a wedge configuration.
Solution Approach 2:
The invention specifies a particular angle range (60° to 72°) for the angle formed by the line segment connecting the contact point and roller center with the radial line. By controlling this angular parameter within the specified range, the design prevents wedge engagement while maintaining proper guidance of the rolling element. This parameter optimization resolves the contradiction between preventing harmful wedge action and ensuring smooth operational guidance.
2Ease of operation
If large wedge angles are designed to prevent wedge engagement, then smooth rotation is maintained, but the structural complexity of the cage increases
Solution Approach 1:
The Gothic arch-shaped curved surface of the holding portion naturally provides the necessary angular geometry to prevent wedge engagement while maintaining structural simplicity. The arc-shaped design inherently creates the appropriate contact angles without requiring complex multi-component structures or adjustable mechanisms.
Solution Approach 2:
By specifying the angle parameter within the 60° to 72° range, the invention achieves smooth rotation and wedge engagement prevention through optimized geometric parameters rather than through structurally complex solutions. This parameter-based approach maintains operational ease while avoiding unnecessary structural complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design effectively prevents damage to the cage's column portion by managing wedge actions between pockets of different phases and single pockets, enhancing the reliability and durability of the bearing.
Implementation Method 1
the friction coefficient between the rolling element and the holding portion
Data Source
Figure 1(a)~1(b)
Figure 2
Figure 3(a)~3(b)
AI summary
Holding portions opposed to each other in a circumferential direction in pockets are formed into a Gothic arch shape by extending and intersecting arcs of each other, and of wedge angles 2θn of a plurality of wedges, which are defined by tangents T to tip end portions of a holding portion in a predetermined pocket and holding portions in the pockets spaced apart in the circumferential direction with respect to the predetermined pocket, when a friction coefficient between a rolling element and a cage is µ, a positive minimum value 2θmin satisfies θmin > tan-1 (µ).