Steering Dust Seal Lip Geometry for Shaft Eccentricity
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Solution Overview
Problem
Existing steering dust seals fail to maintain a sealed space effectively for long periods, leading to compromised sound attenuation due to issues with sliding resistance and potential gaps when the rotational shaft is eccentric.
Innovation Solution
A sealing device with an annular mounted part, inner annular part, bellows part, sound insulation ring, and a circular annular sound insulation lip that maintains contact through an inclined design and protruding wall, preventing separation and ensuring continuous sound attenuation by reducing sliding resistance and restricting excessive lateral movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the sound insulation lip is designed to slide on the sound insulation ring to accommodate shaft eccentricity, then the sealed space can adapt to shaft movement, but the sliding resistance causes the lip to fold or separate, compromising the seal
Solution Approach 1:
The sound insulation ring is designed with an asymmetric inclined surface instead of a symmetric cylindrical surface. The inclination angle is specifically designed so that the lip contacts the inclined surface at an optimal point, allowing the lip to follow shaft eccentricity movements without folding or separating. This asymmetric geometry converts the sliding motion into a controlled following motion that maintains seal integrity.
Solution Approach 2:
The invention changes the geometric parameters of the sound insulation ring by introducing an inclined surface with a specific angle. This parameter change allows the lip to maintain continuous contact with the ring while accommodating shaft eccentricity, transforming the sliding resistance problem into a controlled geometric relationship that preserves seal reliability.
2Object-affected harmful factors
If the sound insulation lip maintains continuous contact with the sound insulation ring to prevent gaps, then sound attenuation is improved, but the sliding resistance increases causing the lip to fold in unexpected orientations
Solution Approach 1:
The inclined surface of the sound insulation ring creates an asymmetric contact geometry that guides the lip's movement. This asymmetric design ensures the lip follows a controlled path that prevents unexpected folding while maintaining continuous contact, thereby blocking sound transmission without compromising lip orientation.
Solution Approach 2:
The inclined surface acts as an intermediary element between the lip and the shaft eccentricity movement. It mediates the interaction by providing a geometric path that allows the lip to follow shaft movement while preventing folding, thus maintaining both sound attenuation and proper lip orientation.
3Ease of operation
If the circular annular part of the sound insulation ring is inclined with greater outer portion distance from the inner annular part, then the distal end of the sound insulation lip can smoothly slide without folding, but the structure becomes more complex
Solution Approach 1:
Instead of making the entire sound insulation ring complex, the invention applies the inclined surface only to the specific circular annular part that contacts the lip. This localized geometric modification provides the necessary sliding smoothness without requiring complex changes to the overall ring structure, thereby maintaining manufacturing simplicity while achieving the desired operational ease.
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 solution effectively maintains a sealed space for extended periods, ensuring consistent sound attenuation and preventing gaps even when the rotational shaft is eccentric, thereby enhancing the durability and noise-reducing capabilities of the steering dust seal.
Implementation Method 1
a circular annular sound insulation lip projecting from the inner annular part or the bellows part toward the sound insulation ring and including a distal end being in slidable contact with the sound insulation ring
Data Source
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AI summary
A sealing device seals a gap between a housing and a rotational shaft located in a shaft hole provided in the housing. The sealing device includes: a mounted part that is to be mounted on the shaft hole; an inner annular part; a seal lip that is to be in contact with the outer peripheral surface of the rotational shaft; a bellows part connecting the mounted part with the inner annular part; a sound insulation ring fixed to the mounted part; and a circular annular sound insulation lip projecting from the inner annular part or the bellows part toward the sound insulation ring. The sound insulation lip protrudes obliquely radially outward. The sound insulation ring includes a circular annular part with which the distal end of the sound insulation lip is in contact. The circular annular part of the sound insulation ring is inclined with respect to an axial direction of the shaft hole such that the distance between an outer portion of the circular annular part and the inner annular part when projected in the axial direction of the shaft hole is greater than the distance between an inner portion of the circular annular part and the inner annular part when projected in the axial direction.