Ball Joint Ferrule Ring Geometry for Dust Sealing and Low Torque
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Solution Overview
Problem
The pinch bolt type ball joints in automobile suspension devices are prone to rust and wear due to dust entering through the cutout, leading to deterioration of the sealing function, and existing ferrule rings either increase manufacturing processes or fail to effectively reduce sliding torque during stud rotation.
Innovation Solution
A ferrule ring with an inclined outer circumferential edge at an obtuse angle is interposed between the knuckle and the small-diameter opening portion of the dust cover, reducing sliding torque and preventing dust entry, while maintaining a simple manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a ferrule ring with a bent outer circumferential edge is used to prevent dust entry, then dust protection is improved, but sliding torque increases during stud rotation
Solution Approach 1:
The patent changes the geometric parameter of the ferrule ring's outer circumferential edge from a bent shape to an inclined shape with a specific angle range (135° to 170°). This parameter optimization reduces the contact area and friction between the ferrule ring and dust cover, thereby reducing sliding torque while maintaining the dust sealing function.
Solution Approach 2:
The inclined outer circumferential edge design allows the ferrule ring to dynamically adapt during stud rotation, reducing the mechanical interference and sliding friction that occurs with bent edges. The inclination angle enables smoother relative motion between components.
2Stability of the object's composition
If the outer circumferential edge is bent toward the dust cover to suppress opening phenomenon, then sealing stability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent specifies an optimized angle range (135° to 170°) for the inclined outer circumferential edge that achieves both sealing stability and ease of manufacture. This parameter optimization allows the ferrule ring to maintain effective contact with the dust cover without requiring complex bending processes, making it suitable for standard manufacturing methods.
3Object-affected harmful factors
If a ferrule ring with complex shaping is used to wrap the small-diameter opening portion, then dust protection is improved, but manufacturing complexity and process time increase
Solution Approach 1:
The patent simplifies the ferrule ring structure by using an inclined outer circumferential edge with a specific angle range instead of complex wrapping shapes. This parameter-based design achieves effective dust protection while maintaining a simple, easy-to-manufacture structure that does not require additional processing steps.
Data Source
AI summary
The disclosure provides a ball joint seal structure that includes a ferrule ring interposed between a small-diameter opening portion of a dust cover and a knuckle. The ball joint connects the knuckle to a stud, and a ball head provided on the end of the stud is accommodated in a socket in a rockable and rotatable manner. The dust cover connects a large-diameter opening that surrounds the socket, which houses the ball head, and a small-diameter opening portion, which surrounds the stud, by a membrane. The ferrule ring includes an annular portion that suppresses the entry of dust through a cutout produced when, for example, a pinch bolt type knuckle is adopted, and has an inclined portion, which inclines toward the dust cover, on the outer circumferential edge thereof.