Helical Compression Spring Radial Shaft Seal High-Speed Centrifugal Compensation
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Solution Overview
Problem
Existing radial shaft seals fail to maintain a secure seal at high speeds due to insufficient contact pressure from tension springs, leading to leakage issues, as conventional designs are inadequate beyond 5000 rpm.
Innovation Solution
A helical compression spring with a pitch of 1.5 mm to 2.3 mm and a winding ratio of less than 4 is used, which reduces mass and increases stiffness, ensuring the sealing lip remains pressed against the surface even at high speeds by compensating for centrifugal forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tension springs with increased rigidity are used to maintain contact pressure at higher speeds, then the contact pressure of the spring is limited by the winding ratio, but it is no longer possible to prevent the sealing lip from lifting at speeds greater than 5000 rpm
Solution Approach 1:
The patent changes the fundamental parameters of the spring system by transitioning from a single tension spring to a combination of compression spring and elastomeric sealing lip. The compression spring provides axial force while the elastomeric lip converts this to radial sealing force, enabling reliable sealing at speeds exceeding 5000 rpm where conventional tension springs fail.
Solution Approach 2:
The invention employs a composite sealing system combining metal compression spring, elastomeric sealing lip material, and friction material. This composite approach allows the sealing lip to maintain contact pressure through the elastic properties of the elastomeric material while being actuated by the compression spring, solving the high-speed sealing problem.
2Reliability
If compression springs are used to achieve necessary contact pressure of the sealing lip on the housing, then sealing is achieved, but undesirably high friction between the sealing lip and the housing occurs due to the compression of the sealing lip and the compression spring
Solution Approach 1:
The patent optimizes the contact pressure parameters by using the compression spring to provide axial force that is converted to controlled radial sealing force through the elastomeric sealing lip. The elastomeric material's elastic properties allow the sealing lip to deform and conform to the housing surface while maintaining appropriate contact pressure, achieving sealing with reduced friction compared to direct compression spring contact.
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 allows for reliable sealing at speeds up to 12000 rpm, minimizing the risk of the sealing lip lifting off or the spring jumping off, thereby preventing undesired leakage and maintaining a secure seal.
Implementation Method 1
centrifugal forces occurring during operation, which act on the sealing lip and the tension spring, must be compensated by the contact pressure of the sealing lip and the tension spring
Implementation Method 2
the contact pressure of the sealing lip on the surface to be sealed, which is necessary for the sealing function of a radial shaft seal, is achieved in these cases by the radial expansion of the elastic sealing lip
Data Source
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AI summary
The ring has a dynamic stressed sealing lip (1) that is laid at a sealed surface (2) of a sealing axis, under elastic prestress. The sealing lip is closed at a radial outer peripheral side by a ring-shaped tension spring (4), which is formed as helical compression spring and comprises windings (6.1) for adjustment of operational centrifugal forces (5). The windings are adjacently arranged at a distance from each other and in a peripheral direction, where each winding has a pitch of 1.5 millimeter. Front-side ends of the spring form a spring lock.