Drum Ball Balancer Control for Washing Machine Vibration Reduction

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing washing machines face challenges in effectively balancing the drum during spin-dry operations, leading to increased noise and vibrations due to unbalanced laundry, as the ball balancer's position cannot be adjusted to compensate for mass unbalance efficiently.

Innovation Solution

A washing machine with a vibration sensor and a controller that detects the eccentric amount and ball position, selects an acceleration pattern from a preset table to position the ball opposite to the unbalanced mass, thereby reducing vibrations and noise without altering the drum's maximum speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a ball balancer is provided in the drum to compensate for mass unbalance, then vibrations and noise are reduced, but the ball cannot be positioned optimally because its movement direction and distance cannot be adjusted

Engineering Contradiction:
Improvevibrations and noiseVSAvoidball position adjustability
Core Design Contradiction:
Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The patent applies dynamics by enabling the ball balancer to transition from a static, freely moving ball to a dynamically controllable system. The controller adjusts the ball's position, movement direction, and movement distance based on detected unbalance conditions, allowing the ball balancer to adaptively compensate for mass unbalance at different drum rotation speeds and phases, thereby resolving the contradiction between vibration reduction and position adjustability

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements feedback by using a vibration sensor to detect vibrations and unbalance conditions, then feeding this information to a controller that adjusts the ball's position accordingly. This closed-loop control system enables the ball balancer to respond to actual unbalance conditions and optimize its position continuously, achieving both vibration reduction and adaptability

Inventive Principle:
Principle #23Feedback

2Productivity

If the drum rotates at high speed during spin-dry operation, then productivity is improved, but unbalanced mass is aggravated due to ball balancer limitations

Engineering Contradiction:
Improvespin-dry operation speedVSAvoidunbalanced mass compensation
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent enables dynamic adjustment of the ball's position based on drum rotation speed. During spin-dry operations at high speeds, the controller detects unbalance conditions and adjusts the ball's position, movement direction, and distance to optimize compensation at each speed level, allowing the system to maintain both high productivity and reliable unbalanced mass compensation across varying operational conditions

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes parameters by adjusting the ball's position, movement direction, and movement distance according to drum rotation speed and detected unbalance conditions. This parameter adjustment allows the ball balancer to effectively compensate for unbalanced mass at different rotation speeds, maintaining reliability while enabling high-speed spin-dry operations for improved productivity

Inventive Principle:
Principle #35Parameter changes

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 reduces unbalanced mass and noise by adjusting the ball balancer's position, enhancing the washing machine's stability and reducing wear on components, without requiring additional sensors or structural changes.

Implementation Method 1

a vibration sensor sensing vibration of the drum

Methodology Applied
Scientific EffectVibration sensing: Vibration

Implementation Method 2

The ball balancer moves in a direction opposite to a direction in which the laundry is off-balance in relation to the center of the drum during rotation of the drum, in particular, during a spin-dry operation in which the drum rotates at a high speed, thus compensating for mass unbalance occurring within the drum

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP3252201B1Washing machine and control method thereof
Publication Date: 2019.04.17 LG ELECTRONICS INC
  • EP3252201B1 patent drawingFigure 1
  • EP3252201B1 patent drawingFigure 2
  • EP3252201B1 patent drawingFigure 3

AI summary

A washing machine includes a drum (30, 32, 3), a vibration sensor (S1005, S920) sensing vibration of the drum (30, 32, 3), a ball balancer (70, 7) installed in a portion of the drum (30, 32, 3) and including at least one ball (401, 71), and a controller controlling a rotation speed of the drum (30, 32, 3), wherein the controller detects information related to an eccentric amount within the drum (30, 32, 3) and a position of the ball (401, 71) using a signal related to vibration of the drum (30, 32, 3) obtained from the vibration sensor (S1005, S920) for a preset period of time, while maintaining a rotation speed of the drum (30, 32, 3), selects an acceleration pattern corresponding to the detected eccentric amount and position of the ball (401, 71) from a preset table (1), and rotates the drum (30, 32, 3) according to the selected acceleration pattern.