Drain Pump Snap Fitting Seal for Axial Noise Suppression

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Solution Overview

Problem

The existing snap fitting structure in drain pumps lacks a reaction force in the axial direction, allowing relative movement between the cover and housing, which generates contact noise due to motor vibration.

Innovation Solution

A drain pump design that includes a ring-shaped seal component seated in a seating section with a pressing section that applies pressure in both the axial and radial directions, preventing relative movement and noise generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a seal component abuts the cover and housing only in the radial direction, then the seal component can be simply structured, but relative movement between the cover and housing in the axial direction cannot be suppressed

Engineering Contradiction:
Improveseal component structureVSAvoidrelative movement suppression
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The seal component is designed to receive pressing forces from two dimensions (radial direction from the housing and axial direction from the cover), transforming a single-direction sealing approach into a multi-directional pressing structure. This resolves the contradiction by maintaining simple component geometry while achieving stability through dimensional diversity in force application.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of manufacture

If the snap fitting structure is used to join the cover and housing, then assembly is simplified, but contact noise is generated when vibration develops due to motor rotation

Engineering Contradiction:
Improveassembly simplicityVSAvoidcontact noise
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The seal component serves as an intermediary element between the cover and housing, filling gaps and suppressing relative movements that cause snap fitting contact noise. This maintains the simple snap fitting assembly structure while eliminating the harmful noise through the intermediary sealing component.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If the seal component is pressed only in the radial direction, then the pressing structure is simple, but the seal is insufficient during axial vibration

Engineering Contradiction:
Improvepressing structureVSAvoidsealing reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The cover acts as a counter-pressing element, applying axial force to balance and supplement the radial pressing force from the housing. This creates a balanced multi-directional pressing system that enhances sealing reliability during axial vibration without significantly increasing overall structural complexity.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

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 suppresses contact noise from the snap fitting portions by ensuring the seal component is pressed in both axial and radial directions, maintaining the seal even during motor vibration.

Implementation Method 1

the seal component is sandwiched pressed by the pressing section in the axial direction and the radial direction... Relative movement between the cover and the housing is thereby suppressed

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4534851A1Drain pump
Publication Date: 2025.04.09 FUJIKOKI CORP
  • EP4534851A1 patent drawingFigure 1
  • EP4534851A1 patent drawingFigure 2
  • EP4534851A1 patent drawingFigure 3~4

AI summary

A drain pump includes a rotary impeller, a lower cover (cover), a housing that together with the lower cover configures a pump chamber to house the rotary impeller, and that is joined in an axial direction X of the rotary impeller to the lower cover by a snap fitting, a ring-shaped O-ring (seal component), and a seating section that is disposed further out than the pump chamber in a radial direction R of the rotary impeller, that is configured from the lower cover and the housing, and that seats the O-ring. The seating section includes an inner conical surface, an outer peripheral face, and a lower face (pressing section) that press the O-ring in the axial direction X and the radial direction R.