Angular Contact Bearing Retainer Notch Geometry for Higher Ball Count
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Solution Overview
Problem
The conventional retainer for angular contact ball bearings faces challenges in accurately manufacturing notches due to non-uniform solidification during injection molding, leading to potential deformation, reduced strength, and rigidity, which affects the circumferential distance between balls and the overall dynamic load rating.
Innovation Solution
The retainer design features pillar portions with notches having a substantially rectangular opening shape, with linear flat surfaces and curved surfaces that allow for a more uniform thickness distribution, enabling precise injection molding and reducing the circumferential distance between pockets while maintaining strength and rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the pillar portions are made thinner to shorten the circumferential distance between balls, then the number of balls that can be held increases and the circumferential distance between balls is reduced, but the manufacturing precision of notches deteriorates due to non-uniform solidification during injection molding
Solution Approach 1:
The pillar portions are designed with non-uniform thickness distribution, where the thickness varies in the circumferential direction. Specifically, the pillar portions have greater thickness at locations corresponding to the notches and smaller thickness at other locations. This local variation in thickness ensures uniform solidification during injection molding, preventing deformation of the notches while still allowing the overall pillar thickness to be reduced to shorten the circumferential distance between balls.
Solution Approach 2:
The thickness parameter of the pillar portions is changed non-uniformly in the circumferential direction. By adjusting the thickness distribution pattern, the design achieves both objectives: reducing the average thickness to shorten ball spacing while maintaining sufficient thickness at critical notch locations for accurate manufacturing during injection molding.
2Quantity of substance
If the pillar portions are made thinner to increase the number of balls, then the circumferential distance between balls is reduced, but the strength and rigidity of the retainer are reduced
Solution Approach 1:
The pillar portions are designed with non-uniform thickness distribution, concentrating greater thickness at locations corresponding to the notches where structural support is most needed. This local reinforcement maintains the strength and rigidity of the retainer while allowing other areas to be thinner, enabling more balls to be accommodated within the same circumferential space.
3Length of moving object
If the pillar portions are made thinner to shorten the circumferential distance between balls, then the number of balls that can be held increases, but the accuracy of notches is reduced due to deformation during manufacturing
Solution Approach 1:
The pillar portions are designed with non-uniform thickness distribution, where the thickness varies in the circumferential direction. Specifically, the pillar portions have greater thickness at locations corresponding to the notches and smaller thickness at other locations. This local variation in thickness ensures uniform solidification during injection molding, preventing deformation of the notches while still allowing the overall pillar thickness to be reduced to shorten the circumferential distance between balls.
Data Source
AI summary
A notch communicating a pair of pockets adjacent to each other in the circumferential direction of pockets of a retainer is provided in a range from an end section on the axially one side to the axially intermediate section of each of pillar portions of the retainer for an angular contact ball bearing, the notch having a substantially rectangular opening shape as seen from the circumferential direction, and an inner surface of the notch having an outer diameter side flat surface portion arranged on the radially outer side from the center of a pocket and extending substantially linearly in the axial direction, an inner diameter side flat surface portion arranged on the radially inner side from the center and extending substantially linearly in the axial direction, and a back side flat surface portion arranged on the axially other side from the center and extending linearly in the radial direction.