Washing Drum Balance Correction for High-Speed Spin Vibration
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Solution Overview
Problem
Conventional horizontal axis washing machines face challenges in balancing loads during high-speed spin cycles, leading to noise and vibrations due to unbalanced wash loads, which existing suspension systems and balancing methods only partially address, especially at higher speeds.
Innovation Solution
A dynamic balancing system that uses sensors to continuously measure forces, accelerations, and angular velocity to calculate and apply balance corrections at specific locations on the drum, accounting for the effects of acceleration, angular momentum, and the location of the center of mass, allowing for precise adjustment of counterbalance masses to minimize imbalances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the machine accelerates to high spin speed, then water extraction efficiency is improved, but noise and vibrations increase due to unbalanced load
Solution Approach 1:
The system performs preliminary detection of load imbalance before high-speed spinning begins. Force sensors detect the magnitude and phase of imbalance forces, and the controller calculates required balance corrections in advance, allowing the balancing chambers to be pre-filled with water to counteract the imbalance before acceleration to high speed
Solution Approach 2:
The system uses water-filled balancing chambers positioned around the drum periphery to create counterbalancing masses. These balance masses are strategically placed to generate forces that oppose and cancel out the imbalance forces caused by unevenly distributed laundry load, thereby reducing vibrations and noise during high-speed operation
2Object-affected harmful factors
If conventional suspension assemblies are used to isolate vibration, then some vibration isolation is achieved, but they never isolate completely and deteriorate with age
Solution Approach 1:
The system extracts and addresses the root cause of vibrations (load imbalance) directly through active balance correction using water-filled chambers, rather than relying on passive suspension assemblies to isolate vibrations after they are generated. This eliminates the dependency on deteriorating suspension components
Solution Approach 2:
The system continuously monitors imbalance forces using force sensors and dynamically adjusts the balance correction by filling or emptying water in the balancing chambers. This closed-loop feedback control actively maintains balance during operation, providing reliable vibration reduction without relying on passive suspension components that deteriorate over time
3Object-affected harmful factors
If suspension assemblies are designed to isolate vibration, then vibration isolation is improved, but significant internal clearance is required, reducing load capacity
Solution Approach 1:
The system performs preliminary balance correction by filling water in balancing chambers before the spin cycle begins. This pre-balancing allows the drum to be rigidly supported with minimal clearance, maximizing load capacity while preventing vibrations from developing during operation
Solution Approach 2:
The water-filled balancing chambers act as adjustable counterweights that actively counteract imbalance forces. This allows the drum support structure to be rigid and compact with minimal internal clearance, thereby maximizing the space available for laundry load while still achieving effective vibration isolation through active balance control
4Object-generated harmful factors
If balance mass is added to counteract imbalance, then vibration is reduced, but the imbalance may not be centered along the axis of rotation, making balancing only partially successful
Solution Approach 1:
The balancing system is divided into multiple independent balancing chambers positioned at different angular locations around the drum periphery. Force sensors at multiple locations detect imbalance forces, and the controller independently controls water filling in each chamber to precisely counteract both radial and axial imbalance components, achieving complete three-dimensional balance correction
Solution Approach 2:
The system extends balance correction from a single-plane approach to a three-dimensional approach by distributing balancing chambers along the drum axis at multiple locations. This allows independent correction of imbalance forces in different axial positions and angular orientations, accurately addressing imbalances that are not centered on the rotation axis
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
This system effectively reduces vibrations and noise during high-speed spin cycles by accurately compensating for both static and dynamic imbalances, enabling washing machines to operate at higher speeds with improved stability and reduced operational costs.
Implementation Method 1
sensors collectively providing: output from which the force component of the supporting force on parallel axes at the two spaced apart support locations can be derived
Implementation Method 2
output from which the acceleration component of acceleration of the two spaced apart support locations on the parallel axes can be derived
Implementation Method 3
a balance correction system able to apply a variable amount of a balance correction mass at a selectable angular location of the drum at at least two spaced apart locations along the drum rotation axis
Implementation Method 4
Dynamic imbalance is more complex. In Figure 2 the axis of rotation 5 is not parallel with one of the principle axes 6 of the object. The principal axes of an object are the axes about which the object will naturally spin.
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A laundry machine includes a drum (11) supported at at least two spaced apart support locations for rotation about a rotation axis (19). A set of sensors collectively provide: output from which the force component of the supporting force on parallel axes at the two spaced apart support locations can be derived, output from which the acceleration component of acceleration of the two spaced apart support locations on the parallel axescan be derived, output from which the angular velocity of said drum rotation axis about an axis through its centre of mass, perpendicular to its rotation axis and parallel to the force component axes can be derived, and output from which the mass of the rotating drum and/or laundry load, and the axial location (along the spin axis) of the centre of this mass, can be continuously derived. A balance correction system (80-85) is able to apply a variable amount of a balance correction mass at a selectable angular location of the drum at at least two spaced apart locations along the drum rotation axis (19). A controller (51) receives outputs of the sensors, and is programmed to continuously calculate balance corrections to apply, the calculation accounting for: a) the effect of acceleration of the force measurement locations on the measured forces, b) the effect conservation of angular momentum has on the measured forces due to angular velocity of the drum rotation axis about an axis through its centre of mass, perpendicular to its spin axis and parallel to the force sensor axis, and c) the effect the axial location of the centre of mass of the rotating drum/load has on the effects in a) and b).