Plastic Ball Bearing Cage with Embedded Metal Insert
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Solution Overview
Problem
High-speed plastic ball bearing cages deflect excessively, leading to wear and failure, while solid cages are too rigid and indentations cause deflection problems at high speeds.
Innovation Solution
A cylindrical plastic cage with a metal insert featuring support tabs and flanges embedded within, which limits the expansion of the cage during high-speed operation by providing structural support and preventing excessive deflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a plastic cage is used for ball bearings, then weight is reduced and manufacturing cost decreases, but at high speeds the cage deflects excessively causing wear and failure
Solution Approach 1:
The invention combines plastic and metal materials to create a composite cage structure. The plastic cage provides lightweight properties and cost benefits, while embedded metal support tabs provide the necessary strength and rigidity at high speeds, resolving the contradiction between weight reduction and reliability.
Solution Approach 2:
Instead of making the entire cage solid metal, the invention applies metal reinforcement only at critical locations where support is needed. The metal support tabs are strategically positioned within the plastic cage structure to provide localized strength, maintaining overall lightness while preventing deflection at high speeds.
2Strength
If solid metal cages are used to prevent deflection, then structural strength increases, but the cages become too rigid causing other deflection problems at high speeds
Solution Approach 1:
The invention applies metal reinforcement only at critical locations where support is needed, rather than making the entire cage solid metal. This localized approach provides necessary strength while maintaining overall flexibility through the plastic structure.
Solution Approach 2:
The invention changes the physical parameters of the cage by embedding metal tabs with specific geometric configurations (flanges, thickness, length) within the plastic structure. This creates an optimized composite structure with balanced strength and flexibility characteristics.
3Ease of manufacture
If indentations are added to the plastic cage to reduce material, then manufacturing cost decreases, but deflection problems worsen at high speeds
Solution Approach 1:
The invention compensates for the strength reduction from indentations by embedding metal support tabs in the plastic cage. The metal tabs provide the necessary reinforcement at critical locations, allowing the cage to maintain indentations for ease of manufacture while preventing deflection through the composite structure.
Data Source
AI summary
A cage and ball sub-assembly, including: an axis of rotation; a cylindrical plastic cage including a circumferentially disposed cage surface, a plurality of indentations extending from the circumferentially disposed cage surface into the cylindrical plastic cage in a first radial direction, and a plurality of pockets, each pocket circumferentially disposed between a respective pair of indentations included in the plurality of indentations; a metal insert including a plurality of support tabs, each support tab embedded in the cylindrical plastic cage, and including a circumferentially disposed portion and a flange extending from the circumferentially disposed portion in a second radial direction; and a plurality of balls disposed within the plurality of pockets. A circular arc, centered on the axis of rotation and orthogonal to the axis of rotation, passes through in sequence: a ball; the cylindrical plastic cage; the first flange of a support tab; and the cylindrical plastic cage.