Ball Balance Ring Control for Washer Drum Resonance
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Solution Overview
Problem
Laundry treating appliances experience undesirable vibrations and movements due to load imbalances during drum rotation, which can lead to inefficient operation and potential damage.
Innovation Solution
A method involving a ball balance ring mounted to the rotatable drum, which determines when the balls are angularly aligned or opposite the imbalance, allowing the drum to be accelerated through its natural frequency to minimize tub movement and redistribute the laundry load effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the drum is rotated at high spin speeds to improve washing efficiency and reduce cycle time, then productivity increases, but load imbalance causes undesirable vibrations and movements that worsen operational stability
Solution Approach 1:
A ball balance ring is mounted to the drum, defining an internal raceway in which a plurality of balls are located. The balls move within the raceway to counterbalance load imbalance forces, with their position adjusted dynamically as the drum rotates to offset the effects of uneven laundry distribution and reduce vibrations.
Solution Approach 2:
The control system dynamically adjusts the rotational speed of the drum based on real-time detection of ball position and drum vibration levels. The method involves determining when the balls are angularly aligned with or opposite the imbalance, and adjusting speed accordingly to pass through natural frequencies safely, transforming a static speed control approach into a dynamic adaptive system.
2Loss of time
If the drum passes through natural frequency quickly to reduce vibration exposure time, then loss of time decreases, but the risk of resonant amplification increases causing harmful vibrations
Solution Approach 1:
The control system continuously monitors the position of the balance balls and the vibration characteristics of the drum, using this feedback to determine the optimal moment to accelerate through the natural frequency. The system detects when balls are angularly opposite the imbalance (a favorable condition for passing through resonance) and timing the acceleration accordingly, creating a closed-loop control system that adapts to real-time conditions.
Solution Approach 2:
The system performs preliminary detection of ball position and imbalance conditions before initiating acceleration through the natural frequency. By determining in advance when the balls will be angularly opposite the imbalance, the control system can plan and execute the speed transition at the optimal moment, preventing resonant amplification before it occurs.
3Reliability
If the drum speed is reduced to minimize vibration damage, then reliability improves, but productivity and washing efficiency deteriorate
Solution Approach 1:
The system employs periodic redistribution phases during the spin cycle where the drum speed is temporarily reduced to allow the balance balls to reposition themselves against the imbalance. This periodic action redistributes the laundry load more evenly, after which the drum accelerates back to high spin speeds for the remainder of the cycle, achieving a balance between reliability and productivity through rhythmic speed variations.
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 approach reduces vibrations and movements of the washing machine, ensuring a more balanced and efficient operation by redistributing the laundry load, thereby improving the overall performance and longevity of the appliance.
Implementation Method 1
rotating the drum at or above a satellizing speed... determining when the plurality of balls are angularly aligned with an imbalance of laundry in the drum during the rotation of the drum
Implementation Method 2
accelerating the rotational speed of the drum through a natural frequency of the washing machine when the plurality of balls are determined to be angularly opposite the imbalance of laundry in the rotatable drum
Data Source
AI summary
A method operating a laundry treating appliance having a rotatable drum at least partially defining a treating chamber for receiving a laundry load for treatment according to an automatic cycle of operation and a ball balance ring mounted to the rotatable drum and defining an internal raceway in which a plurality of balls are located, where the method includes rotating the drum at or above a satellizing speed, determining positions of the plurality of balls, and accelerating the rotational speed of the drum based on the determined positions of the plurality of balls.