Oil Seal Labyrinth Design for Torque and Leakage Reduction
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Solution Overview
Problem
Conventional oil seals using fabric as a dust lip face high sliding torque and air leakage issues, making it difficult to achieve zero air leakage threshold during inspection.
Innovation Solution
An oil seal design incorporating a rubber-like elastic dust lip, an intermediate lip, and a thread groove on the slinger, which reduces sliding torque and prevents air leakage by forming a labyrinth seal and using the intermediate lip to direct air away from the dust lip during inspection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If fabric is used as a dust lip with great fastening margin to enable uniform expansion, then the fabric can be uniformly expanded circumferentially, but the sliding torque of the fabric becomes high
Solution Approach 1:
The patent changes the material parameter from fabric to rubber-like elastic body, which has different elastic properties. The rubber material allows for lower tensile strength requirements while maintaining uniform expansion, thereby reducing the sliding torque generated by the dust lip.
2Reliability
If fabric is used as a dust lip with breathability, then air intake function is improved, but air leakage occurs during inspection making zero threshold inspection impossible
Solution Approach 1:
The patent changes the material property from breathable fabric to non-breathable rubber-like elastic body. This material parameter change eliminates the air leakage issue while the intermediate lip with projection structures maintains the air intake function by creating pressure differential pathways.
Solution Approach 2:
The patent segments the sealing function into multiple components: the rubber-like elastic dust lip for contact sealing, the intermediate lip with projections for air intake control, and the main lip for primary sealing. This segmentation allows each component to specialize in one function, resolving the contradiction between air intake and air leakage prevention.
3Object-affected harmful factors
If intermediate lip is provided with projection structures to form labyrinth seal, then dust sealing is improved, but device complexity increases
Solution Approach 1:
The patent uses a flexible rubber-like elastic intermediate lip with integrated projection structures. The flexibility of the rubber material allows the projections to maintain contact with the slinger surface while accommodating shaft eccentricity, achieving effective dust sealing without requiring complex rigid structures.
Solution Approach 2:
The patent employs composite design by integrating multiple functional elements (projections, labyrinth structures, sealing surfaces) into a single rubber-like elastic intermediate lip component. This composite approach achieves complex dust sealing functionality while maintaining manufacturing simplicity through monolithic construction.
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 design effectively reduces sliding torque and allows for zero air leakage threshold inspections by utilizing a rubber-like elastic dust lip and intermediate lip to create a labyrinth seal and prevent air entry, maintaining seal integrity even with shaft eccentricity.
Implementation Method 1
a dust lip which is arranged in an external side of the main lip and is constructed by a rubber-like elastic body
Implementation Method 2
a sliding torque of the fabric is high, thereby preventing an improvement of fuel efficiency
Implementation Method 3
a thread groove which carries out a pumping action toward an outer side in a diametrical direction in an end surface in an external side of the flange portion
Implementation Method 4
the first projection is provided with a structure which makes the dust hard to pass through toward the lip end by forming a micro gap in relation to the outer peripheral surface of a tubular portion in the slinger
Implementation Method 5
the intermediate lip slidably directs its lip end to a machine inner side, comes into close contact with an outer peripheral surface of a tubular portion in the slinger
Data Source
AI summary
A slinger of an oil seal has a thread groove carrying out a pumping action toward a diametrically outer side in an external side end surface of a flange portion. A lip seal member has a main lip, a rubber-like elastic dust lip and a rubber-like elastic intermediate lip. The intermediate lip directs a lip end to a machine inner side, comes into close contact with the slinger over a whole periphery with the lip end, and has annular first projections and circumferentially partial second projections in a facing portion to the slinger. The first projection has a structure which makes dust hard to pass through to the lip end by forming a micro gap in relation to the slinger. The second projection has a structure which properly keeps the micro gap under generation of eccentricity in a rotary shaft by having a higher portion than the first projection.