Ball Joint Seal Structure for Gap-Coupled Knuckle Assemblies
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional ball joints with coupling members having gaps face challenges in maintaining long-term sealing performance due to foreign matter accumulation and wear, often requiring complex structures or additional components.
Innovation Solution
A ball joint design featuring a dust cover with an annular concave and convex portion on the shaft, a pinch bolt for coupling, and an inclined top surface on the seal portion to prevent foreign matter accumulation and ensure effective sealing, even when the knuckle has a gap.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a gap is provided in the coupling member for assembly and adjustment, then ease of manufacture and assembly is improved, but foreign matter can enter through the gap causing reduced sealing performance over time
Solution Approach 1:
The sealing function is segmented into multiple components: the dust cover with seal portion, the annular convex portion, and the inclined surface. Each segment addresses a specific aspect of sealing - the seal portion provides primary sealing, the convex portion prevents foreign matter entry, and the inclined surface directs contaminants away, collectively maintaining sealing performance despite the gap
Solution Approach 2:
The seal portion of the dust cover acts as an intermediary element between the shaft portion and the coupling member gap. It bridges the gap area, preventing foreign matter from directly entering the joint while allowing the gap to remain for assembly purposes
2Reliability
If a complex sealing structure is added to prevent foreign matter entry through the gap, then sealing performance is improved, but device complexity increases
Solution Approach 1:
Multiple sealing functions are merged into a single integrated dust cover component. The dust cover combines the seal portion, the annular convex portion, and the inclined surface into one piece that performs primary sealing, foreign matter prevention, and contaminant redirection simultaneously, avoiding the need for multiple separate components
Solution Approach 2:
The dust cover is designed as a multi-functional component that simultaneously provides sealing, foreign matter prevention, and contaminant management. The single component performs multiple roles that would traditionally require separate elements, simplifying the overall structure while maintaining comprehensive sealing performance
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 stabilizes sealing performance over a long period by preventing foreign matter from accumulating on the seal portion and entering the inner surface, thus reducing wear and maintaining effective sealing.
Implementation Method 1
the seal portion 642 slides relative to the shaft portion of the ball stud 610 and the knuckle 630, and sealing performance is thereby maintained
Implementation Method 2
the body portion 641 of the dust cover 640 deforms, and sealing performance is thereby maintained
Implementation Method 3
an inclined top surface on the seal portion to prevent foreign matter accumulation
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Provided is a ball joint capable of stably maintaining sealing performance over a long period even when a coupling member includes a gap. In the ball joint, a shaft portion 120 of a ball stud includes an annular concave portion 121 and an annular convex portion 122 that is disposed at a position above the annular concave portion 121 and below a coupling part between the shaft portion 120 and a knuckle 300, an inner peripheral surface side of a seal portion 430 of a dust cover is configured to be slidably in close contact with both of an outer peripheral surface of the annular concave portion 121 and an outer peripheral surface of the annular convex potion 122, an outer peripheral surface side of the seal portion 430 is provided with a clamping member 520 that clamps the seal portion 430 to the shaft portion 120, and a top surface 444 of the seal portion 430 facing the knuckle 300 is constituted by an inclined surface generated by the seal portion tapering down in diameter toward the knuckle 300.