Magnetic Balancer Structure for Washing Machine Drum Vibration
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Solution Overview
Problem
Washing machines experience vibration and noise due to unbalanced loads during drum rotation, which can lead to damage to components like the drum and motor, as laundry concentrates at specific sections without even distribution, causing eccentric rotation.
Innovation Solution
A balancer system with a housing having an annular channel, movable masses, and magnets with alternating N and S poles is used to offset unbalanced loads by restricting mass movement within a specific RPM range, utilizing magnetic force and inclined sidewalls to counteract centrifugal forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a balancer is used to offset unbalanced load, then vibration and noise are reduced, but the complexity of the device increases due to additional components like magnets and grooves
Solution Approach 1:
The balancer system uses the drum's own rotation to generate centrifugal force that automatically positions the masses into the grooves at specific RPM ranges, eliminating the need for external control mechanisms. The system self-regulates by utilizing the operational conditions (rotation speed) to activate the balancing function.
Solution Approach 2:
The magnetic force between the magnet and masses changes with the drum's rotation speed (RPM). At low RPM, magnetic force dominates and restricts mass movement. At high RPM, centrifugal force overcomes magnetic force, allowing masses to move into grooves. This parameter-based control simplifies the device by using natural physical variations rather than mechanical controls.
2Reliability
If magnets are used to restrict mass movement at specific RPM ranges, then balancing performance is improved, but manufacturing precision requirements increase due to specific gap and length ratios
Solution Approach 1:
The design specifies optimal parameter ranges (gap: 1-3mm, magnet-to-mass length ratio: 1:0.6 to 1:1.4) that create a natural transition point between low-RPM and high-RPM behavior. By tuning these parameters, the system achieves reliable mass restriction at operating speeds while allowing free movement during imbalance conditions, balancing performance with manufacturability.
3Force
If the magnet length is optimized relative to groove dimensions, then mass restriction effectiveness is improved, but the device complexity increases due to multiple dimensional constraints
Solution Approach 1:
The magnet is positioned and dimensioned specifically for its interaction with the masses in the grooves. The magnet extends beyond the groove ends to ensure complete coverage and effective restriction of mass movement. This localized optimization ensures that magnetic force is applied precisely where needed without requiring complex overall structural 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 balancer effectively stabilizes drum rotation, reduces vibration and noise, and prevents component damage by ensuring even load distribution during washing and dehydration cycles.
Implementation Method 1
at least one magnet coupled to an outer surface of the balancer housing to restrict the mass accommodated in the groove when an RPM of the drum is within a specific RPM range
Implementation Method 2
When the drum is rotated, a direction of centrifugal force acting on the mass may be perpendicular to a direction of magnetic force of the magnet acting on the mass
Data Source
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AI summary
A balancer (100) of a washing machine (1) having improved balancing performance. The balancer includes a balancer housing (110) having an annular channel (110a) therein, at least one mass (141) movably disposed in the channel at least one groove (121) recessed in an inner surface of the balancer housing so as to accommodate the mass, and at least one magnet (160) coupled to an outer surface of the balancer housing to restrict the mass accommodated in the groove when an RPM of the drum is within a specific RPM range. The magnet is configured as a plurality of N poles and S poles which are arranged alternately, and the outermost pole of the magnet among the plural N poles and S poles has a relatively shorter length than another adjacent pole.