Thin-Section Ball Bearing With Dual Ball Sets for Low-Friction Stiffness
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Solution Overview
Problem
Thin-section ball bearings used in robotic joints face a trade-off between high stiffness, which increases friction and torque, leading to decreased responsiveness and efficiency.
Innovation Solution
A thin-section bearing design with two sets of balls, each making four-point contact with inner and outer raceways, forming an eight-point contact bearing, combined with different diameter balls to enhance stiffness and reduce friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the bearing is designed with increased stiffness to support high loading, then the load-bearing capacity is improved, but the friction within the bearing increases, leading to higher torque requirements and decreased responsiveness
Solution Approach 1:
The bearing is divided into two distinct ball sets: a first ball set with larger diameter balls and a second ball set with smaller diameter balls. Each ball set contacts the raceways at different locations, creating an eight-point contact configuration. This segmentation allows the bearing to distribute loads more efficiently while reducing friction, as each ball set can be optimized for specific loading conditions rather than using a uniform ball configuration throughout.
2Ease of manufacture
If the bearing uses a constant ring thickness design, then the manufacturing simplicity is maintained, but the ability to optimize performance for specific applications is limited
Solution Approach 1:
The bearing employs different ball diameters in different locations: larger balls in the first ball set and smaller balls in the second ball set. This local differentiation allows each region of the bearing to be optimized for its specific functional requirements, enabling performance optimization for various applications while maintaining the overall simplicity of the thin-section bearing design.
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 bearing achieves high stiffness with low friction, supporting substantial radial and axial loading while maintaining compactness and ease of assembly.
Implementation Method 1
a first ball set includes a plurality of first balls disposed between the first inner raceway and the first outer raceway, each first ball having a first diameter and contacting each one of the curved surface sections of both of the first inner and outer raceways
Data Source
AI summary
A thin-section bearing includes an inner ring connectable with an inner member and having first and second inner raceways spaced axially apart. Each inner raceway has a pair of curved surface sections each having a radius of curvature with a separate center, the two centers being spaced axially apart. A multi-piece outer ring is disposed coaxially about the inner ring, is connectable with an outer member and has first and second outer raceways spaced axially apart. Each outer raceway has a pair of curved surface sections each having a radius of curvature with a separate center, the two centers being spaced axially apart. A first ball set is disposed between the first inner and outer inner raceways and a second ball set is disposed between the second inner and outer raceways. The balls of the first ball set have a greater diameter than the balls of the second set.