Rolling Bearing Cage with Spherical Pocket Walls
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Solution Overview
Problem
Existing rolling bearings with cylindrical pockets on the radially inner side face interference issues during high-speed rotation, leading to increased break-in time, heat generation, and reduced rigidity, which affects performance and noise levels.
Innovation Solution
A cage design with annular members featuring spherical portions on pocket walls and cutout portions on the radially inner and outer sides to prevent interference, reduce grease entry, and enhance grease release, using ceramic balls for reduced weight and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If cylindrical pockets are used on the radially inner side to prevent interference, then interference between balls and pockets is avoided, but gaps between balls and pockets increase causing excessive grease entry and increased break-in time
Solution Approach 1:
The pocket shape is made non-uniform: cylindrical on the radially inner side to prevent interference, and tapered on the radially outer side to reduce gap volume. This local differentiation allows each region to serve its specific function optimally.
Solution Approach 2:
The radially outer side of the pocket is designed with a tapered curved shape rather than a straight cylindrical extension, which reduces the gap volume between the ball and pocket while maintaining smooth grease flow paths.
2Object-affected harmful factors
If cylindrical pockets on the radially inner side are used to provide interference avoidance, then balls and pockets do not interfere, but rigidity is reduced due to reduced wall thickness
Solution Approach 1:
The cage structure employs different geometries in different regions: cylindrical pockets on the radially inner side for interference avoidance, and tapered pockets on the radially outer side to increase wall thickness and enhance rigidity where needed.
Solution Approach 2:
The pocket geometry transitions from cylindrical to tapered in the radial dimension, which allows the wall thickness to be increased in the radial direction while maintaining the interference-free condition at the ball contact point.
3Object-affected harmful factors
If cylindrical pockets on the radially inner side are used, then interference is prevented, but deformation due to centrifugal force is increased
Solution Approach 1:
The pocket geometry is optimized locally: cylindrical shape on the radially inner side maintains stability under centrifugal force by preventing interference, while the tapered shape on the radially outer side provides structural support to reduce overall deformation.
4Loss of time
If arc-shaped cutout portions are formed to improve grease scraping performance, then break-in time is reduced, but centrifugal force deforms pockets narrowing axial gaps causing interference
Solution Approach 1:
Instead of using arc-shaped cutouts that cause deformation, the invention uses a tapered pocket shape on the radially outer side that provides grease scraping functionality while maintaining pocket stability under centrifugal force.
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
The design ensures high-speed rotation performance by preventing interference, reducing break-in time, heat generation, and noise, while maintaining rigidity and improving grease distribution.
Implementation Method 1
action of a centrifugal force on the cage rotating at high speed deforms the pockets
Implementation Method 2
the amount of heat generation is increased due to shear between the grease and the balls in the interiors of the pockets
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A rolling bearing is provided which includes a cage (3) including two annular members (11) each including (i) pocket walls (9) each having a recess, and (ii) connection plates (10) circumferentially alternating with the pocket walls (9), and each coupling together corresponding ones of the pocket walls (9), the two annular members (11) being axially opposed to each other such that pockets (2) are circumferentially defined by the recesses of the pocket walls (9) of the two annular members (11); an inner ring (5) having an inner ring raceway surface (4) on an outer peripheral surface of the inner ring (5); an outer ring (7) disposed on an outer peripheral side of the inner ring (5), the outer ring (7) having an outer ring raceway surface (6) on an inner peripheral surface of the outer ring (7); and balls (8) interposed between the inner ring (5) and the outer ring (7), the balls (8) being retained in the respective pockets (2), which are defined in the cage (3), wherein spherical portions (17) are formed on the respective pocket walls (9) of the two annular members (11), the spherical portions (17) being out of contact with the balls (8) in a state where the balls (8) are in abutment with circumferential ends of the pockets (2).