Silicone Boot Stress Dispersion via Thin Portion Buckling
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Solution Overview
Problem
The existing silicone boots for constant velocity universal joints are prone to stress concentration and fatigue cracks due to their design, leading to reduced durability and potential failure under varying temperature conditions and operational stresses.
Innovation Solution
A silicone boot design featuring a smaller diameter portion with a thin portion and a circumferential groove at the corner of the thick portion, allowing for buckling deformation and stress dispersion, which prevents excessive load application and reduces the likelihood of cracks, while maintaining sufficient strength for shaft attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a thick coupling portion is formed between the shaft attachment portion and the bellows portion to ensure structural strength, then the boot has sufficient strength for shaft attachment, but stress concentrates at the corner portion between the fitting groove and the bellows portion, leading to fatigue cracks and reduced durability
Solution Approach 1:
The patent applies local quality by creating a thin portion with reduced thickness specifically at the coupling portion between the shaft attachment portion and the bellows portion. This localized thinning reduces stress concentration at the corner portion near the fitting groove while maintaining sufficient overall structural strength for shaft attachment, thereby preventing fatigue cracks and improving durability
2Stability of the object's composition
If the boot structure is made rigid to maintain shape and prevent collapse, then structural stability is improved, but the boot cannot adequately follow the deformation of the constant velocity universal joint during operation, leading to stress concentration and potential failure
Solution Approach 1:
The patent applies dynamics by creating a thin portion that allows controlled flexibility and deformation. This thin portion enables the boot to dynamically adapt to the deformation of the constant velocity universal joint during operation, while the overall structure maintains sufficient stability through the remaining thicker portions
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 improved design effectively suppresses crack formation and enhances the durability of the silicone boot, ensuring stable operation and preventing dust intrusion and grease leakage over time, even under severe environmental conditions.
Implementation Method 1
a thin portion extending from the shaft attachment portion so as to be coupled with the bellows portion through intermediation of a thick portion and allowing buckling deformation with respect to the shaft attachment portion and the bellows portion
Implementation Method 2
a silicone material is known as the most effective material capable of enduring both the high temperature atmosphere of 140°C or higher and the low temperature atmosphere of -40°C or lower
Data Source
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AI summary
Provided are a silicone boot for a constant velocity universal joint and a constant velocity universal joint, in which occurrence of cracks in a smaller diameter portion of the boot is suppressed and durability thereof is improved. The silicone boot for a constant velocity universal joint includes: a larger diameter portion (13) attached to an outer joint member (2) of a constant velocity universal joint; a smaller diameter portion (14) attached to a shaft (9) coupled with an inner joint member (4) of the constant velocity universal joint; and a bellows portion (15), which is arranged between the larger diameter portion (13) and the smaller diameter portion (14), and has peak portions (7) and valley portions (6) formed alternately with each other. The smaller diameter portion (14) includes: a shaft attachment portion (37) having a radially outer surface in which a fitting groove (19) for attachment of a boot band is formed; and a thin portion (38) extending from the shaft attachment portion (37) so as to be coupled with the bellows portion (15) through intermediation of a thick portion (25) and allowing buckling deformation with respect to the shaft attachment portion (37) and the bellows portion (15).