Rolling Bearing Creep Prevention via Segmented Key Groove
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Solution Overview
Problem
Conventional sealed rolling bearing apparatuses experience stress concentration at key grooves, leading to reduced basic dynamic load rating and hindering downsizing due to the need for extended key grooves to prevent creep.
Innovation Solution
A rolling bearing apparatus with a first key groove on the inner ring's axial end portion, opened at the inner peripheral face and extending axially from a certain depth on the outer peripheral face, and a second key groove on the rotation shaft, forming a continuous key groove that disperses force on the edge part, preventing creep while maintaining dynamic load rating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inner ring is extended and the first key groove is formed by cutting a portion of the end face, then creep is prevented, but stress concentration occurs at the edge part of the key groove and the basic dynamic load rating is lowered
Solution Approach 1:
The key groove is segmented into two parts: a first key groove formed on the inner peripheral face and a second key groove formed on the outer peripheral face of the inner ring. This segmentation allows the key to be supported by both faces, distributing the stress and preventing stress concentration at a single location, thereby maintaining the basic dynamic load rating while preventing creep.
Solution Approach 2:
The key groove structure transitions from a single-face cutout to a two-dimensional configuration involving both the inner peripheral face and the outer peripheral face of the inner ring. By extending the key groove into the radial dimension (from the inner face) and providing a corresponding groove on the outer face, the stress distribution is improved without requiring axial extension of the inner ring, thus maintaining load rating.
2Object-affected harmful factors
If the axial length of the rolling element is made shorter to accommodate the seal, then sealing is achieved, but the basic dynamic load rating is remarkably lowered
Solution Approach 1:
Instead of solving the creep prevention problem in the axial dimension (which would require extending the inner ring beyond the seal), the invention moves the key groove formation to the radial dimension by utilizing both the inner peripheral face and outer peripheral face of the inner ring. This allows the rolling element axial length to remain sufficient for maintaining basic dynamic load rating while the seal can be properly positioned.
Data Source
AI summary
In a creep preventing rolling bearing apparatus 21, an inner ring 12 is provided with a first key groove 13 opened at an inner peripheral face 12i in an axial end portion 12t. The first key groove 13 is provided so as to have a predetermined length L in the axial direction from the axial end portion 12t at a position having a certain depth D from an outer peripheral face 12o in a radial direction. A rotation shaft 17 is provided with a second key groove 13′ on an outer peripheral face 17o along an axial direction. The first key groove 13 and the second key groove 13′ are aligned and a key 18 is inserted, whereby the first key groove 13 and the second key groove 13′ are fixed at the same time.