Lip Seal Pumping Asperities for Leakage and Wear
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional lip-type shaft seal devices experience leakage when at rest and fail to sustain reduced friction over time due to wear, and they either compromise sealing or lubricating performance.
Innovation Solution
A lip-type shaft seal device with pumping parts featuring periodic structures of linear asperities on the rotary member's surface, which create a pumping action to draw and return sealed fluid, preventing leakage and maintaining lubrication during both rest and operation, with the lip seal extending axially to cover the pumping parts and ensure effective sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sealing edge part contacts the arrow-shaped grooved part formed of high-hardness material, then the pumping effect is achieved to repel foreign matter and push back fluid, but the sealing edge part wears down quickly
Solution Approach 1:
The patent applies local quality by creating periodic structures (asperities) only in specific regions where pumping action is needed, while keeping other areas smooth for sealing. The asperities are formed with specific dimensions (height 1-10μm, width 10-50μm, pitch 50-200μm) to provide pumping effect without excessive wear, resolving the contradiction between achieving pumping function and maintaining seal durability.
Solution Approach 2:
The patent changes the surface parameters by forming periodic asperity structures with controlled height, width, and pitch on the sealing surface. This transforms the flat sealing surface into a structured surface that provides both pumping action and reduced wear, allowing the sealing edge to maintain its function longer while achieving fluid pumping.
2Object-affected harmful factors
If the grooves are deep (2.5 μm or greater) to create pumping action, then foreign matter is repelled, but sealed fluid leaks out when the device is at rest
Solution Approach 1:
The patent applies local quality by creating periodic structures (asperities) only in specific regions where pumping action is needed, while keeping other areas smooth for sealing. The asperities are formed with specific dimensions (height 1-10μm, width 10-50μm, pitch 50-200μm) to provide pumping effect without excessive wear, resolving the contradiction between achieving pumping function and maintaining seal durability.
Solution Approach 2:
The patent changes the surface parameters by forming periodic asperity structures with controlled height, width, and pitch on the sealing surface. This transforms the flat sealing surface into a structured surface that provides both pumping action and reduced wear, allowing the sealing edge to maintain its function longer while achieving fluid pumping.
3Use of energy by moving object
If the lip seal is optimized for low torque through reduced constriction force, then sliding torque is reduced, but sealing performance deteriorates and outside air infiltrates
Solution Approach 1:
The patent applies self-service by using the sealed fluid itself to generate pumping action through the periodic asperity structures. The fluid flowing over the asperities creates a pumping effect that reduces the constriction force needed on the seal lip, thereby reducing torque while maintaining sealing performance. The system uses its own operating fluid to provide the pumping function rather than requiring additional external mechanisms.
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 prevents leakage at rest, forms a lubricant film during startup to reduce sliding torque, and maintains reliable sealing and lubrication during operation by utilizing the pumping action of the periodic asperities, enhancing both sealing and lubricating functions.
Implementation Method 1
pumping parts for creating pumping action through relative rotational sliding of the lip seal and the rotary member
Implementation Method 2
forms a lubricant film during startup to reduce sliding torque
Data Source
Figure 1
Figure 2
Figure 3
AI summary
{Technical Problem} Provided is a lip seal-type shaft seal device that experiences no leakage when at rest; that, during rotation, including the initial period of rotation, operates by fluid lubrication while preventing leakage; and that can simultaneously achieve sealing and lubricating functions. {Solution to Problem} In a lip-type seal shaft seal device equipped with a lip seal for sealing a rotary member and a stationary member concentrically disposed to the inside and outside in a radial direction, pumping parts for creating pumping action through relative rotational sliding of the lip seal and the rotary member are formed in continuous fashion in the circumferential direction on the outside peripheral surface of the rotary member. The pumping parts are configured of intake pumping parts for acting on a sealed fluid in the intake direction, and discharge pumping parts for acting on the sealed fluid in the discharge direction, respectively arranged independently. A lip of the lip seal extends in the axial direction towards the outside atmosphere side leaving a portion of the pumping parts on the sealed fluid side exposed.