Steering Pinion Seal Protector for Dust-Blocking Labyrinth Sealing
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Solution Overview
Problem
Vehicle steering assemblies face challenges in preventing dust and debris from entering the annular space around the pinion shaft, despite the use of dust covers and grease, due to flexing under varying conditions and ambient changes.
Innovation Solution
A disk-shaped protector is installed within the annular space, combined with a dust cover and pinion shaft, creating a labyrinth path that limits debris entry by covering a portion of the opening and extending radially to form a serpentine path with the dust cover, effectively sealing the space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a dust cover is used to protect the annular space, then dust and debris protection is improved, but the dust cover flexes under varying conditions and ambient changes allowing debris entry
Solution Approach 1:
The protection system is divided into multiple segments: the rigid dust cover, the flexible protector member with radially extending portions, and the pinion shaft. This segmentation allows each component to perform its specialized function - the dust cover provides overall coverage while the protector member's flexible portions adapt to thermal expansion and contraction, maintaining the seal without compromising reliability.
Solution Approach 2:
The protector member incorporates radially extending portions that can flex and move dynamically in response to thermal expansion and contraction of the pinion shaft and housing. This dynamic capability allows the seal to maintain contact and prevent debris entry under varying temperature and ambient conditions, resolving the reliability issue while preserving dust protection.
2Object-affected harmful factors
If grease is used to retain dust and debris, then debris retention is improved, but grease can degrade over time and lose effectiveness
Solution Approach 1:
The protector member with its radially extending portions creates a physical labyrinth barrier before debris can reach the grease. This preliminary mechanical barrier reduces the reliance on grease for debris retention, allowing the grease to maintain its effectiveness for longer periods by not being constantly challenged by incoming contaminants.
Solution Approach 2:
The protector member acts as an intermediary between the external environment and the grease-filled annular space. It provides a first line of defense that filters and redirects debris, reducing the burden on the grease and extending its effective service life while maintaining debris retention capabilities.
3Ease of operation
If the annular space is left open for pinion shaft access, then ease of assembly is improved, but dust and debris can easily enter the space
Solution Approach 1:
The protector member is nested within the annular space, with its radially extending portions positioned between the dust cover and the pinion shaft. This nested configuration creates a labyrinth path that maintains open access for pinion shaft assembly while simultaneously blocking debris entry, resolving the contradiction between ease of operation and protection.
Solution Approach 2:
The protection mechanism extends into the radial dimension with radially extending portions that create multiple barriers. This dimensional approach allows the opening to remain accessible for assembly while the radially extending structures create a complex path that prevents straightforward debris entry, maintaining both accessibility and protection.
Data Source
AI summary
A vehicle steering assembly that includes a housing, a pinion shaft, a seal, a protector and a dust cover. The housing defines a bore with the pinion shaft extending therethrough. The seal is disposed within the bore spaced apart from the end of the housing. The seal extends around the pinion shaft creating a seal therebetween. The housing and the pinion shaft define an annular space therebetween and between an opening at one end of the housing and the seal. The protector is fitted to the housing covering a portion of the opening and the annular space. The protector has a shaft receiving opening with the pinion shaft extending therethrough and out of the housing. The dust cover is attached to the housing completely covering the protector and the opening of the bore.