Washing Machine Drum Seal Assembly for Low-Friction Leak Control
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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 also 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 from flange and sleeve portions to exert axial and radial pressure, with a toroidal spring and undulated circumferential groove to reduce friction and maintain sealing efficiency through a hydrodynamic effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high contact pressure is exerted by spring-loaded sealing lips, then sealing efficiency is improved, but friction increases and energy consumption rises
Solution Approach 1:
The patent changes the pressure application mechanism from continuous spring loading to intermittent hydrodynamic pressure generation. The sealing lips are loaded by wash fluid pressure rather than mechanical springs, transforming the pressure application from constant to variable based on operating conditions, thereby reducing friction and energy consumption while maintaining sealing efficiency
Solution Approach 2:
The patent uses hydraulic pressure from the wash fluid to load the sealing lips instead of mechanical spring loading. The undulated circumferential groove generates hydrodynamic pressure that automatically adjusts the sealing lip contact pressure based on fluid flow conditions, eliminating the need for spring mechanisms and reducing energy consumption
2Reliability
If high contact pressure is exerted by sealing lips, then sealing efficiency is improved, but wear of sealing lips increases rapidly
Solution Approach 1:
The patent transforms the pressure application from constant mechanical spring loading to variable hydrodynamic pressure. The sealing lips experience pressure only when needed for sealing, reducing continuous contact and wear, while maintaining sealing efficiency during operation through fluid-pressure actuation
Solution Approach 2:
By using wash fluid pressure to load the sealing lips instead of springs, the system reduces mechanical wear. The hydrodynamic pressure generated by the undulated groove provides sealing force only when fluid is present, minimizing dry friction and wear during non-operational phases
3Object-affected harmful factors
If rigid plastic shield is used to protect seal assembly, then protection against wash fluid contact is improved, but device size increases and design becomes bulkier
Solution Approach 1:
The sealing member performs multiple functions: it seals against wash fluid, protects the bearing, and eliminates the need for a separate rigid protective shield. The integrated design combines sealing and protection functions in a single component, reducing overall assembly size
Solution Approach 2:
The patent uses a flexible elastomeric sealing member instead of a rigid plastic shield. The flexible material provides both sealing and protective functions while occupying minimal space, eliminating the bulkiness associated with rigid protective shields
4Reliability
If conventional seal assembly is used in washing machine with vibration and direction changes, then sealing function is maintained, but noise increases significantly
Solution Approach 1:
The patent changes the pressure loading mechanism from mechanical springs to hydrodynamic fluid pressure. This eliminates the mechanical impact and vibration associated with spring-loaded seals during drum direction changes and vibrations, significantly reducing noise while maintaining sealing function
Solution Approach 2:
By using wash fluid pressure to load the sealing lips instead of mechanical springs, the system eliminates the noisy mechanical impacts that occur during drum direction changes and vibrations. The fluid pressure system responds smoothly to operational changes, reducing noise generation
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 reduced friction, silent operation, and compact design with minimal wear, maintaining sealing efficiency over the lifespan of the sealing lips, while reducing energy consumption and noise.
Implementation Method 1
a toroidal spring, which exerts a radial thrust on the first lip
Implementation Method 2
defined by a radially inner, undulated, circumferential groove of the second lip
Data Source
Figure 1
AI summary
A seal assembly (1) including a first rigid shield (11) having an annular sealing member (12) of elastomeric material, and a second rigid shield (13) mounted facing the first and having respective sliding surfaces (14; 15) for a first and second annular sealing lip (16; 18) of the annular sealing member, which extend towards the second rigid shield to exert axial sealing pressure and radial sealing pressure, respectively; wherein the first annular sealing lip (16) has a radial seat (30) facing the opposite way to the second annular sealing lip and housing a toroidal spring, which exerts a radial thrust on the first annular sealing lip eccentrically with respect to an elastic hinge defined by a root portion (33) common to the first and second annular sealing lip, and having a centre of rotation (C) located along a line (R) extending through a V-shaped sealing edge (34) of the first annular sealing lip and forming a 20° to 60° angle (γ) with a radial plane; the root portion (33) being defined between two opposite annular recesses (40; 41) of the annular sealing member, which have a U-shaped radial section and bottom walls facing each other and substantially aligned along the aforementioned line (R); and the second annular sealing lip (18) having a V-shaped sealing edge (38) defined by an undulated, circumferential groove (W).