CV Joint Boot with Arc-Linear Shoulder for Durability
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Solution Overview
Problem
The existing boots for constant velocity universal joints suffer from non-uniform thickness in the shoulder portion, leading to stress concentration and durability issues when colliding with foreign objects, and the large diameter portion is prone to misalignment with the outer joint member.
Innovation Solution
A boot design with a circular arc and linear portion on the shoulder and root portions, respectively, providing uniform thickness and a stress dispersion effect, along with a thermoplastic polyester elastomer material, ensures proper engagement and increased durability by preventing stress concentration and misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the shoulder portion is formed with a thin thickness and chamfered portion to enable engagement with the outer joint member, then the boot can be properly positioned and engaged, but the nonuniform thickness causes stress concentration and deteriorates durability
Solution Approach 1:
The invention replaces the chamfered portion with a circular arc portion having a curved profile. This curvature distributes stress more evenly across the shoulder portion when foreign objects collide with the boot, eliminating the stress concentration that occurs at the sharp edges of chamfered portions. The circular arc shape maintains engagement capability while significantly improving durability.
2Ease of operation
If the shoulder portion has an outer shape protruding radially outward to facilitate engagement, then the boot can be properly positioned on the outer joint member, but the protruding shape causes stress concentration upon collision with foreign matters
Solution Approach 1:
The circular arc portion with its curved profile eliminates sharp protrusions that concentrate stress. The smooth curvature allows the shoulder portion to maintain its engagement function while distributing collision forces from foreign objects across a broader area, reducing stress concentration and preventing damage.
3Device complexity
If the large diameter portion is engaged with the outer joint member without additional positioning features, then the structure is simpler, but the large diameter portion may move past the predetermined position and fail to engage properly
Solution Approach 1:
The circular arc portion on the shoulder portion serves a dual function: it maintains the simple overall structure while simultaneously providing the positioning function. The curved profile engages with the outer joint member in a way that automatically limits the movement of the large diameter portion, ensuring proper engagement position without requiring additional positioning features or complex mechanisms.
Data Source
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AI summary
Provided is a boot for a constant velocity universal joint capable of being properly engaged with an outer joint member of a constant velocity universal joint and capable of increasing durability thereof. Over a shoulder portion (5) and a root portion (13) of a boot (1) for a constant velocity universal joint according to the present invention, there are formed a circular arc portion (14) adjacent to a large diameter portion (2) and having an axial sectional shape protruding radially outward and a linear portion (15) adjacent to the circular arc portion (14) and having a linear axial sectional shape. An inner peripheral surface (16) of the linear portion (15) is brought into contact with an opening end portion (17) of an outer joint member (7) of a constant velocity universal joint (6) such that a thickness from the circular arc portion (14) to the linear portion (15) is uniform.