Brushless DC motor and drain pump having the same

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Solution Overview

Problem

The accumulation of foreign substances and water infiltration into the rotor side of drain pumps in household appliances leads to malfunction and reduced convenience due to interference with rotor rotation, especially as the pumps operate over time.

Innovation Solution

An improved sealer structure comprising a sealer cover, gasket, and sealer base that supports the gasket at multiple points, including a first and second annular protruding portion, to prevent water inflow and follow the axial movement of the rotor, enhancing the sealing effectiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional single-point gasket support structure is used, then the device complexity is low, but water infiltration into the rotor side occurs and sealing effectiveness deteriorates

Engineering Contradiction:
Improvesealing effectivenessVSAvoidsealer structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The sealer base is divided into multiple functional regions with separate support portions (first support portion and second support portion) that independently support the gasket at different locations. This segmentation allows each support portion to independently maintain sealing pressure, improving overall sealing effectiveness while distributing structural complexity across modular components

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a single-point support structure to a multi-point distributed support structure in the radial dimension. By adding support portions at different radial positions and heights, the sealing contact is distributed across multiple dimensions, enhancing sealing reliability without proportionally increasing overall device complexity

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

2Reliability

If the sealer structure is rigid and fixed, then manufacturing precision is easier to achieve, but the sealer cannot follow the axial movement of the rotor and sealing effectiveness deteriorates

Engineering Contradiction:
Improvesealer follow-up capabilityVSAvoidsealer structure fabrication
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The sealer structure incorporates dynamic elements including elastic members that can deform and the support portions that can move relative to each other in the axial direction. This allows the sealer to dynamically follow rotor axial movement while maintaining sealing contact, improving reliability without requiring complex active control mechanisms

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention utilizes changes in physical parameters of the elastic members (such as elasticity and deformation) to enable the sealer to adapt to rotor movement. By selecting appropriate material parameters and geometric parameters for the elastic members, the sealer achieves follow-up capability through passive elastic deformation rather than active control

Inventive Principle:
Principle #35Parameter changes

3Reliability

If water infiltration prevention is not prioritized, then device complexity is low, but foreign matter accumulation and rotor rotation interference occur leading to pump failure

Engineering Contradiction:
Improvepump operational reliabilityVSAvoidsealer system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The sealer structure is designed to proactively prevent water infiltration before it can cause damage to the rotor or motor. By positioning the gasket and support portions to maintain continuous sealing contact, the system prevents foreign matter accumulation and water damage in advance, improving pump reliability without requiring complex monitoring or intervention systems

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3582373B1Brushless DC motor and drain pump having the same
Publication Date: 2023.03.01 LG ELECTRONICS INC
  • EP3582373B1 patent drawingFigure 1
  • EP3582373B1 patent drawingFigure 2
  • EP3582373B1 patent drawingFigure 3

AI summary

A motor according to the present disclosure may include a first housing having a groove, a rotor inserted into the groove and rotatably provided outside the first housing, a second housing coupled to the first housing to form a predetermined space together with an outer circumferential surface of the groove, a stator fixedly provided in the space, a rotation shaft coupled to the rotor and extended in one direction, and a sealer coupled to the first housing to surround the rotation shaft, wherein the sealer includes a sealing base rotatably coupled to the rotation shaft, a gasket formed to be brought into contact with a plurality of points on an outer circumferential surface of the rotation shaft, and a sealing cover coupled to the sealing base to fix the sealing member to the sealing base, and the sealing base includes a first annular protruding portion spaced apart from the rotation shaft to support the gasket, and a second annular protruding portion spaced apart from the first annular protruding portion to support the gasket.