Electromagnet Actuator for Active Drum Balancing in Washing Machines
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Solution Overview
Problem
Existing balancer systems for washing machines suffer from drawbacks such as increased noise and vibration at low rpm, slow and complex balancing processes during spinning, and high costs and complexity due to the use of electromagnetic actuators with moving parts.
Innovation Solution
An active balancing system utilizing an electromagnet in the balancing unit that interacts with a ferromagnetic outer race of the housing, allowing for low friction movement and controlled braking without moving parts, enabling efficient balancing across a wide rpm range including resonance frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electromagnetic actuators with moving parts are used to balance the drum, then the balancing function can be achieved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent replaces electromagnetic actuators with moving parts with a passive balancing ring system where balancing masses move freely under gravitational and centrifugal forces. This substitution eliminates complex electromagnetic mechanisms while achieving the same balancing function through purely mechanical force fields.
Solution Approach 2:
The invention extracts and removes the electromagnetic actuator components from the balancing system, retaining only the essential balancing masses and their movement mechanism. This simplification maintains the core balancing function while eliminating unnecessary complexity.
2Reliability
If electromagnetic actuators with moving parts are used, then the balancing control can be achieved, but the response time increases due to moving part mass
Solution Approach 1:
The patent replaces electromagnetic actuators with moving parts with a passive balancing ring system where balancing masses move freely under gravitational and centrifugal forces. This substitution eliminates complex electromagnetic mechanisms while achieving the same balancing function through purely mechanical force fields.
Solution Approach 2:
The invention uses the full force of gravity and centrifugal acceleration to move the balancing masses, allowing them to respond immediately to unbalance conditions without being limited by actuator response times. The masses are given excessive freedom to move rather than being controlled by incremental actuator steps.
3Device complexity
If a balancer ring with free-moving masses is used, then the structure is simplified, but the balancing process becomes slow and complex during spinning
Solution Approach 1:
The patent utilizes the periodic gravitational and centrifugal forces during drum rotation to drive the balancing masses into their correct positions. The rhythmic tumbling motion during washing and the centrifugal force during spinning create periodic action that naturally guides the masses to counterbalance unbalanced loads.
Solution Approach 2:
The invention changes the operational parameters by utilizing different force regimes: during washing, gravitational force dominates as the drum tumbles, while during spinning, centrifugal force becomes dominant. This parameter change enables fast balancing response across different operational phases without mechanical intervention.
4Reliability
If balancing masses are used to counterbalance unbalanced load, then the drum rotation can be stabilized, but the system generates noise and vibration during low rpm operation
Solution Approach 1:
The patent employs a dynamic balancing ring system where the balancing masses can freely adjust their positions based on the operational phase. During low rpm washing, the masses move with the tumbling drum without creating excessive noise, while during high rpm spinning, they rapidly settle into counterbalancing positions to stabilize rotation.
Solution Approach 2:
The patent utilizes the periodic gravitational and centrifugal forces during drum rotation to drive the balancing masses into their correct positions. The rhythmic tumbling motion during washing and the centrifugal force during spinning create periodic action that naturally guides the masses to counterbalance unbalanced loads.
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 system achieves fast reaction times, high reliability, and low friction forces, allowing for efficient balancing across a wide rpm range, including above resonance frequencies, thereby improving customer satisfaction and appliance reliability.
Implementation Method 1
an electromagnet in the balancing unit that interacts with a ferromagnetic outer race of the housing channel
Implementation Method 2
a wheel that transfers to the outer race the largest part of the acceleration force acting on the balancing unit
Implementation Method 3
The appliance controller, to balance the drum load, exploits the action of gravitational and inertial forces acting on the balancing units
Implementation Method 4
The appliance controller, to balance the drum load, exploits the action of gravitational and inertial forces acting on the balancing units
Data Source
AI summary
A laundry treating appliance including a tub, a drum rotatably mounted inside the tub, at least one transmitter coil wound around the drum axis configured to supply wireless electrical power; at least one ring shaped housing mounted centered to the drum on its perimeter, having an annular channel defined therein; at least one balancing unit having a body forming its exterior permitting its movement in the the channel, the balancing unit has at least, one receiver coil having its winding axis perpendicular to the transmitter coil winding axis configured to receive wireless power from the transmitter coil and actuator means powered by the receiver coil; an appliance manager controlling the complete laundry treating appliance operation, configured to manage the positioning of the balancing unit and to drive the transmitter coil based on the position of the balancing unit and the drum unbalance, characterized in that the actuator means is an electromagnet configured to create a friction force resulting of the magnetic attraction between its magnetizing surface and one ferromagnetic race present on one of the housing sides. Methods to control such a laundry treating appliance are also disclosed.