Wheel Bearing Elastic Member Scratches via Retracted Surface
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Solution Overview
Problem
The existing wheel bearing apparatus suffers from damage to the elastic member and impaired sealability due to linear scratches on the fitting surface of the outer member during the fitting process, which affects the reliability and sealability of the wheel bearing.
Innovation Solution
A wheel bearing apparatus design featuring a first cap with a cylindrical fitting portion and a radially inward extending bottom portion, where the elastic member is press-contacted against a retracted surface with a larger diameter than the fitting surface, preventing scratches and damage, and a pulser ring with varying magnetic characteristics is used to maintain detection accuracy without increasing the cap's size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cap is press-fitted into the outer member during assembly, then the sealability is improved by the elastic member contacting the fitting surface, but linear scratches are caused on the fitting surface which damage the elastic member and impair sealability
Solution Approach 1:
A retracted surface is introduced as an intermediary between the fitting surface and the elastic member. The retracted surface has a larger diameter than the fitting surface, causing the elastic member to contact this retracted surface instead of the fitting surface during press-fitting. This mediator prevents direct contact between the elastic member and the fitting surface, thereby avoiding linear scratches while maintaining sealability.
2Reliability
If the cap size is increased to improve sealability, then the sealing performance is enhanced, but the overall size of the wheel bearing apparatus increases
Solution Approach 1:
The retracted surface is designed with a larger diameter than the fitting surface, creating a localized enlarged contact area for the elastic member. This local quality change allows the elastic member to be pressed against a larger surface area without increasing the overall cap dimensions, thereby improving sealability while maintaining compact size.
3Reliability
If the elastic member is pressed against the fitting surface to ensure sealability, then the sealing contact is improved, but the elastic member is damaged due to scratches on the fitting surface
Solution Approach 1:
The retracted surface serves as a protective intermediary that prevents the fitting surface from directly contacting the elastic member during press-fitting. By transferring the contact point to the retracted surface with larger diameter, the fitting surface scratches are avoided, thereby protecting the elastic member from damage while maintaining the sealing function.
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 enhances sealability and reliability by preventing scratches and damage to the elastic member, while maintaining detection accuracy and offering increased design flexibility without compromising the air gap or size of the wheel bearing apparatus.
Implementation Method 1
the elastic member being press-contacted against the retracted surface with being elastically deformed
Implementation Method 2
a pulser ring with varying magnetic characteristics is used to maintain detection accuracy
Data Source
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AI summary
One object of the present invention is to provide a wheel bearing apparatus which does not cause any damage on the elastic member even if any linear scratch would be caused on the fitting surface of the outer member by the cap during fitting thereof and improve the sealability of the fitting portion and the reliability of the wheel bearing apparatus. For achieving the object mentioned above, there is provided a wheel bearing apparatus comprising an outer member; an inner member including a hub wheel and at least one inner ring, double row rolling elements contained between the outer raceway surfaces and inner raceway surfaces respectively of the outer member and the inner member; and a first cap press-fitted into an inboard-side opening of the outer member, the first cap comprising a cylindrical fitting portion press-fitted into an inside fitting surface of the outer member and a bottom portion extending radially inward from the fitting portion to cover the inboard-side end of the inner member, and the first cap being integrally adhered on its inboard-side outer circumference of the fitting portion with an elastic member of synthetic rubber via vulcanized adhesion and the elastic member projecting radially outward beyond the outer diameter of the fitting portion characterized in that the inner circumference of the inboard-side end of the outer member is formed by an inside fitting surface into which the first cap is press-fitted and a retracted surface formed inboard-side from the inside fitting surface via a step portion and having a larger diameter than that of the inside fitting surface, and that the elastic member is press-contacted against the retracted surface with being elastically deformed.