Rolling Bearing Seal Ring Surface Grinding
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Solution Overview
Problem
Conventional rolling bearing units experience seal loss and damage during the press fitting of slinger and seal rings due to sharp corners and uneven surfaces, leading to grease leakage and foreign matter ingress, especially after heat treatment and grinding processes.
Innovation Solution
The rolling bearing unit incorporates a combined seal ring design with a slinger and seal ring, where the surfaces corresponding to the slinger and seal ring fitting surfaces are ground simultaneously after heat treatment to form smooth, continuous sections without sharp corners, ensuring proper alignment and preventing damage during press fitting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If heat treatment and grinding processes are performed on the inner ring or outer ring, then the hardness and dimensional precision are improved, but sharp corners and uneven surfaces are generated at the joining sections, causing seal damage and loss
Solution Approach 1:
The invention performs preliminary rounding of sharp corners at the joining sections before the heat treatment and grinding processes. By pre-shaping the surfaces to eliminate sharp corners in advance, the subsequent thermal and mechanical processes do not generate harmful uneven surfaces that would damage the seal, thus preventing seal loss while maintaining dimensional precision.
Solution Approach 2:
The invention applies a protective measure by rounding the sharp corners beforehand to cushion against the potential damage that would occur during press fitting. This preliminary action creates a buffer that prevents the sharp edges from concentrating stress and damaging the seal ring during assembly, thereby protecting the sealing function.
2Strength
If the slinger and seal ring are pressed fitted onto the inner ring or outer ring, then the assembly is secured, but the sharp corners at the joining sections cause damage to the cylindrical sections and seal loss
Solution Approach 1:
The invention performs preliminary rounding of sharp corners at the joining sections before the press fitting operation. By eliminating sharp corners in advance, the press fitting process can proceed without generating stress concentrations that would damage the cylindrical sections of the slinger or seal ring, thus maintaining seal integrity while achieving secure assembly.
Solution Approach 2:
The invention converts the potentially harmful sharp corners into beneficial rounded surfaces through preliminary rounding. This transformation turns what would be a source of stress concentration and damage into a feature that distributes stress evenly during press fitting, protecting the seal while maintaining assembly strength.
3Reliability
If conventional separate sealing structures are used, then the sealing function is provided, but the seal ring is vulnerable to damage from sharp corners and uneven surfaces during manufacturing
Solution Approach 1:
The invention merges the slinger and seal ring into a combined seal ring structure where the seal ring is integrated with the slinger. This unified structure allows the sharp corner rounding to protect both components simultaneously, and the seal ring benefits from the protective effect of the rounded joining sections while maintaining its sealing function.
Solution Approach 2:
The invention performs preliminary rounding of sharp corners at the joining sections before assembly, protecting the seal ring from damage during the press fitting process. This advance preparation ensures the seal ring maintains its integrity and sealing capability without being compromised by manufacturing-induced sharp edges.
Data Source
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AI summary
Construction of a rolling bearing unit with a combined seal ring that enables press fitting of a cylindrical section 15 of a slinger 13 to be pressure fitted on to a slinger fitting surface 20 of an inner ring 19a without losing the seal between the slinger fitting surface 20 and the cylindrical section 15 is achieved. Of the surface of the inner ring 19a, the continuous section that comprises a portion corresponding to the slinger fitting surface portion 20, a portion corresponding to the chamfered section 25a and a joining section 27a between these portions are simultaneously ground with a formed grindstone. As a result, the continuous section is entirely formed into a flat surface with no non-differential corners in the cross section, or in other words, with no sharp corners.