Ball Joint Dust Cover Structure to Prevent Flange Contact
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Solution Overview
Problem
Conventional ball joint dust covers with bellows-shaped bodies face durability issues due to contact with the ball stud's flange portion during deformation, leading to reduced sealing performance and potential breakage.
Innovation Solution
A dust cover design with a deformable bellows-shaped body that includes a cover portion continuously covering the radially outward tip end of the flange portion and a part decreasing in diameter towards the spherical portion, preventing contact with the flange portion during deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a bellows-shaped body portion is employed to increase deformation amount, then the sealing performance during swinging motion is improved, but the body portion comes in contact with the flange portion causing durability degradation
Solution Approach 1:
The dust cover is divided into distinct functional portions: a body portion for deformation, a sealing portion for contactless sealing, and a cover portion for protection. The sealing portion includes an inner peripheral sealing portion and a cover portion that continuously covers the flange portion, separating the deformation function from the sealing function to prevent contact between the body portion and flange portion.
Solution Approach 2:
The sealing portion acts as an intermediary element between the body portion and the flange portion. It provides the sealing function while preventing direct contact between the body portion and flange portion, thereby eliminating the durability issue while maintaining sealing performance.
2Reliability
If the outer diameter of the body portion is increased to prevent contact with other members, then the sealing performance is improved, but the amount of deformation is limited reducing response to swinging motion
Solution Approach 1:
The dust cover design allows deformation in the axial direction while maintaining a constrained outer diameter. The bellows-shaped structure enables the body portion to expand and contract axially to accommodate swinging motion without increasing the radial dimension, thus preventing contact with surrounding members while maintaining sealing performance.
3Adaptability or versatility
If the body portion deforms to respond to ball stud swinging, then the sealing performance is maintained, but contact with the flange portion causes degradation over time
Solution Approach 1:
The dust cover is segmented into a body portion that deforms during swinging motion and a sealing portion that remains separated from the flange portion. This segmentation ensures that deformation occurs in the body portion without causing contact and degradation at the sealing interface, thereby extending service life.
Solution Approach 2:
The sealing portion serves as a mediator that maintains the sealing function while preventing direct interaction between the deforming body portion and the flange portion. This mediation eliminates the degradation mechanism while preserving the necessary deformation capability for sealing.
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
This design effectively suppresses contact between the dust cover body and the ball stud's flange portion, enhancing durability and maintaining sealing performance even during swinging and rotating motions.
Implementation Method 1
the body portion 710 deforms so that the sealing performance is maintained
Implementation Method 2
the sealing portion 730 slides relative to the shank portion 120 of the ball stud 100 so that the sealing performance is maintained
Data Source
AI summary
Provided are a ball joint and a dust cover that make it possible to suppress contact of a body portion of the dust cover with the vicinity of a flange portion of a ball stud. A dust cover integrally includes: a deformable bellows-shaped body portion made of an elastic body; a fixed portion made of an elastic body and provided on one end side of the body portion; and a sealing portion made of an elastic body and provided on the other end side of the body portion. The sealing portion includes: an inner peripheral sealing portion configured to be slidable on a part of a shank portion on the opposite side of the shank portion from a spherical portion with respect to a flange portion; and a cover portion that continuously covers, in an outer wall surface of the flange portion, a radially outward tip end portion and a part of a portion that decreases in diameter from the tip end portion toward the spherical portion side.