Laundry treating appliance and methods of operation
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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 ramp the drum from low to high speed when the balance masses are out of phase with the load, thereby reducing the likelihood of contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the drum is accelerated from low speed to high speed, then treatment efficiency is improved, but during acceleration the balance masses and load imbalance may align, causing excessive vibration and container-tub contact
Solution Approach 1:
The patent applies preliminary action by detecting the phase relationship between balance masses and load imbalance before initiating or continuing acceleration. The controller monitors the rotational position and calculates phase differences during low-speed operation. When the phase relationship indicates potential alignment that would cause excessive vibration during acceleration, the controller delays or modifies the acceleration command. This preliminary detection and preventive action avoids the harmful alignment condition while still enabling efficient operation at high speed.
Solution Approach 2:
The patent uses feedback by continuously monitoring rotational speed, torque, and position sensors to determine the real-time phase relationship between balance masses and load imbalance. This feedback information is fed to the controller, which adjusts acceleration commands or balance ring operation accordingly. The closed-loop feedback mechanism ensures that acceleration only occurs when phase relationships are favorable, preventing container-tub contact while maintaining treatment efficiency.
2Quantity of substance
If larger drums are used to increase capacity, then laundry treating capacity is improved, but the appliance size and potential imbalance issues increase
Solution Approach 1:
The patent applies counterweight principles by incorporating balance rings with adjustable or controllable masses that can be positioned to counteract the imbalance created by larger drum sizes and varied laundry loads. The controller coordinates the balance masses to offset the increased moment of inertia and potential imbalance from larger drum capacity. This allows the system to accommodate larger drums for increased capacity while using active counterbalancing to manage the associated complexity and potential instability.
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 minimizes tub-container contact, reduces potential damage, and extends the appliance's lifespan by ensuring balanced operation during speed changes, enabling the use of larger drums without increasing the appliance's size.
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.