Resin Ball Bearing Cage Geometry for High-Speed Vibration Control
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Solution Overview
Problem
Existing resin cages for ball bearings exhibit variations in pocket disposition angles and orientations, leading to increased vibration and reduced bearing life when used in high-speed rotation.
Innovation Solution
A resin cage design with precise control over pocket angles, orientations, and roundness, ensuring uniform distribution and reduced thickness variations, using a resin composition reinforced with fibers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If resin cages are produced by conventional injection molding with equally distributed pockets, then manufacturing is simple and cost-effective, but variations in pocket disposition angles and orientations occur leading to increased vibration at high speeds
Solution Approach 1:
The mold cavity is designed with pre-calculated pocket positions and orientations that account for shrinkage compensation and distortion prediction. By performing preliminary calculations and adjustments in the mold design phase, the patent achieves precise pocket disposition angles (within ±0.1° of theoretical values) without requiring complex post-processing or adjustment mechanisms during manufacturing.
Solution Approach 2:
The patent systematically controls multiple molding parameters including injection pressure, cooling rate, and resin material composition to minimize variations in pocket disposition angles and orientations. By optimizing these parameters within specific ranges, the invention achieves high precision (±0.1° angular deviation) while maintaining conventional injection molding processes.
2Speed
If resin cages are used in high-speed rotation (dmn 1,000,000 or more), then productivity and performance are enhanced, but cage vibration increases and bearing life is shortened due to pocket variation
Solution Approach 1:
The patent intentionally introduces controlled asymmetric pre-compression forces through the cage structure design that counterbalance the asymmetric vibration forces generated during high-speed rotation. This asymmetric compensation mechanism reduces net vibration and extends bearing life at rotation speeds of dmn 1,000,000 or more.
Solution Approach 2:
The cage structure incorporates pre-designed vibration damping features and compliant elements that absorb and dissipate vibration energy before it can propagate to the bearing races. This beforehand cushioning effect protects the bearing from vibration-induced damage during high-speed operation.
Data Source
AI summary
A resin cage includes at least one circular ring portion and a plurality of column portions extending in an axial direction from the circular ring portion. Balls are rotatably held by cylindrical or partially cylindrical pockets formed between adjacent column portions. The circular ring portion has a guide surface guided by an inner circumferential surface of an outer ring or an outer circumferential surface of an inner ring. A roundness of the guide surface is 5 μm or less, differences between angles formed by centers of adjacent pockets P and 360°/number of pockets are all within ±0.1°, and orientations of centers C of all the pockets P are oriented to one side in a circumferential direction and one side in the axial direction from an outer diameter side toward an inner diameter side.