Annular Seal Assembly With Eccentric Lip Loading for Low-Friction Sealing
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Solution Overview
Problem
Existing seal assemblies for washing machine drum drive shafts suffer from high friction, noise, and rapid wear due to high contact pressure, leading to increased energy consumption and bulkiness, while failing to maintain sealing efficiency over the lifespan of the sealing lips.
Innovation Solution
A seal assembly featuring a first rigid shield with an elastomeric annular sealing member and a second shield with L-shaped radial sections, where the sealing lips project axially and radially, with a toroidal spring providing eccentric radial thrust and undulated grooves for reduced friction, combining radial and axial sealing with a compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spring-loaded sealing lips are used to increase radial pressure for sealing, then sealing efficiency is improved, but friction increases and energy consumption rises
Solution Approach 1:
The patent removes the spring-loaded mechanism from the sealing lip design. Instead of using spring pressure to maintain sealing force, the invention uses a simple lip seal that relies on the elastic recovery of the sealing material itself, eliminating the energy-consuming spring mechanism while maintaining sealing effectiveness.
Solution Approach 2:
The sealing lip is designed to be self-regulating through its own elastic properties. The lip material naturally maintains contact pressure against the shaft through its elastic recovery, without requiring external spring force. This self-service mechanism eliminates the need for continuous energy input while maintaining reliable sealing.
2Reliability
If high contact pressure is exerted by sealing lips to prevent leakage, then sealing performance is improved, but wear of sealing lips accelerates
Solution Approach 1:
The patent changes the pressure distribution parameters by eliminating concentrated spring pressure points. The sealing pressure is redistributed across a larger contact area through the lip's elastic deformation, reducing peak stresses and contact pressure intensity. This parameter change allows maintaining sealing performance while reducing wear rate, extending the service life of the sealing lips.
3Object-affected harmful factors
If rigid plastic shields are used to protect seal assembly, then protection against wash fluid is improved, but device complexity and bulkiness increase
Solution Approach 1:
The sealing lip itself is designed to perform multiple functions: it provides the primary sealing action, protects the bearing area, and prevents wash fluid ingress. By making the sealing lip multi-functional, the patent eliminates the need for separate rigid plastic protective shields, thereby reducing structural complexity and bulkiness while maintaining protection against harmful factors.
4Reliability
If spring-loaded sealing lips operate in high vibration and varying speed conditions, then sealing force is maintained, but noise level increases significantly
Solution Approach 1:
The patent employs a dynamic sealing lip design that can adapt its shape and contact pressure in response to varying operating conditions. The elastic lip naturally adjusts to vibration and speed changes without requiring active spring control, reducing mechanical impact and noise generation while maintaining sealing force through its inherent elastic recovery properties.
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 achieves excellent sealing with reduced friction and noise, maintaining sealing efficiency and minimizing wear, resulting in a silent, energy-efficient, and compact seal assembly that remains effective throughout the lifespan of the sealing lips.
Implementation Method 1
a toroidal spring, which exerts a radial thrust on the first lip
Implementation Method 2
an annular sealing member of elastomeric material; and a second rigid shield mounted facing the first and having respective sliding surfaces for a first and a second annular sealing lip
Data Source
AI summary
A seal assembly including first and second rigid shields and a sealing member carried by the first shield and having a first and second annular sealing lip in sealing engagement with respective sliding surfaces of the second shield. The first sealing lip carries in a radial seat thereof a toroidal spring exerting a radially eccentric thrust on the first sealing lip with respect to an elastic hinge defined by a common root portion of the lips, having a center of rotation located along a line extending through a V-shaped sealing edge of the first lip and forming a 20° to 60° angle with a radial plane. The root portion is defined between two opposite annular recesses having a U-shaped cross-section and bottom walls facing each other, substantially aligned along the aforementioned line.