Laundry Drum Balance Ring Control to Reduce Container-Tub Contact
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Solution Overview
Problem
Existing balance rings in horizontal axis washing machines exacerbate load imbalances during low-speed rotation, leading to container-tub contact and potential damage, as they add to the imbalance when their masses are in phase with the load imbalance, particularly at low speeds.
Innovation Solution
A method involving a parameter estimator that monitors torque, acceleration, and speed to determine the relative positions of the laundry load and balance masses, allowing for optimal timing to accelerate the drum's rotational speed and minimize contact by ensuring the balance masses are out of phase with the load imbalance during the ramping process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If balance rings with masses are used to counteract load imbalance during drum rotation, then the ability to balance the load is improved, but the imbalance is exacerbated when the masses are in phase with the load imbalance at low speeds
Solution Approach 1:
The balance masses are made movable within the balance ring rather than being fixed, allowing them to dynamically adjust their position based on drum speed and load conditions. At low speeds, the masses can move to positions that minimize imbalance, while at higher speeds they settle into positions that provide effective counterbalancing.
Solution Approach 2:
The system changes the operational parameters of the balance masses based on drum speed. Below a threshold speed, the masses are allowed to move freely or are actively positioned to minimize imbalance. Above the threshold speed, the masses are locked or guided into positions that provide optimal counterbalancing effect.
2Productivity
If the drum is accelerated from low speed to high speed during operation, then the treatment efficiency is improved, but container-tub contact occurs due to imbalance at low speeds
Solution Approach 1:
Before accelerating the drum to high speed, the system first allows the balance masses to settle into appropriate positions or actively positions them to minimize imbalance. This preliminary action ensures that when acceleration begins, the imbalance forces are minimized, preventing container-tub contact during the transition to high-speed operation.
Solution Approach 2:
The system dynamically adjusts the balance mass positions during the acceleration process, transitioning from a low-speed configuration that minimizes imbalance to a high-speed configuration that provides effective counterbalancing, thereby preventing container-tub contact throughout the speed transition.
3Productivity
If larger drum sizes are used to increase treating capacity, then the laundry treatment capacity is improved, but the appliance size increases
Solution Approach 1:
The balance ring with movable masses provides an effective counterweight mechanism that compensates for load imbalance in larger drums. This allows the use of larger drum capacities without proportionally increasing appliance size, as the balance ring system efficiently manages the increased imbalance forces that would otherwise require a larger overall appliance structure.
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 the likelihood of container-tub contact, extends the appliance's lifespan, and allows for larger drum sizes without increasing the appliance's size, by accurately determining the optimal phase difference and counterbalancing the load during the transition from low to high-speed rotation.
Implementation Method 1
at least one balance ring mounted to the drum and defining an internal annular cavity in which a mass is located
Data Source
AI summary
Methods of reducing a likelihood of contact between a rotating laundry-container, such as a basket or drum, located within a tub of a laundry treating appliance where the method includes rotating the drum during a measurement period, determining a torque, speed, acceleration, and position of the drum, using a parameter estimator to estimate the position of a mass relative to an imbalance of laundry and accelerating the rotation of the drum when the mass is determined to be angularly spaced from the relative position of the imbalance of laundry.