Washer Drum Balance Ring Phase Control for Tub Contact Avoidance
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Solution Overview
Problem
Existing balance rings in horizontal axis washing machines fail to effectively counteract load imbalances at low speeds, leading to container-tub contact during rotational acceleration, as they can exacerbate imbalances when their masses are in phase with the load imbalance, particularly at low speeds like 90 rpm, and increase total imbalances during ramping to high speeds.
Innovation Solution
A laundry treating appliance with a drum and balance ring system that includes a controller and parameter estimator to monitor torque, acceleration, and rotational speed, allowing for the determination of relative positions of the load and balance masses, and adjusting the drum's rotation speed to avoid phase alignment and minimize imbalances by accelerating when the balance masses are out of phase with the load imbalance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If balance rings are used to counteract load imbalances, then balancing effectiveness is improved at high speeds, but container-tub contact occurs during low-speed rotational acceleration
Solution Approach 1:
The patent applies dynamics by making the balance ring system adaptive through real-time monitoring and control. The controller continuously monitors drum speed, acceleration, and position, and dynamically adjusts the balance ring configuration or motor operation based on the detected imbalance conditions and phase relationships between balance masses and load imbalance. This dynamic adaptation allows the system to prevent container-tub contact during low-speed acceleration while maintaining balancing effectiveness at high speeds.
Solution Approach 2:
The patent implements feedback by using sensors to monitor drum operational parameters (speed, acceleration, position) and the controller's determination of relative positions between balance masses and load imbalance. This feedback loop enables the system to detect when balance masses are in phase with load imbalance and adjust operations accordingly, preventing the harmful container-tub contact during critical acceleration phases.
2Reliability
If balance masses are positioned to counteract load imbalance, then imbalance reduction is achieved, but total imbalance increases when balance masses are in phase with load imbalance at low speeds
Solution Approach 1:
The patent replaces the purely mechanical balance ring system with an intelligent control system that uses sensors and a controller to monitor and analyze the phase relationship between balance masses and load imbalance. This substitution allows the system to detect when mechanical positioning would create harmful in-phase conditions and adjust operations (such as delaying acceleration or adjusting balance ring configuration) to prevent total imbalance increase, thereby resolving the contradiction between imbalance counteraction and total imbalance stability.
3Productivity
If drum rotation is accelerated from low to high speed, then productivity is improved, but container-tub contact occurs during critical speeds
Solution Approach 1:
The patent applies preliminary action by having the controller monitor and determine the relative positions of balance masses and load imbalance before initiating or continuing drum acceleration. This advance detection allows the system to identify favorable conditions (when balance masses are out of phase with load imbalance) and proceed with acceleration, or to delay acceleration until favorable conditions exist, thereby preventing container-tub contact during critical speeds while maintaining productivity.
Solution Approach 2:
The patent implements parameter changes by dynamically adjusting operational parameters (drum acceleration rate, target speeds, or balance ring configuration) based on the real-time phase relationship between balance masses and load imbalance. When the controller detects that balance masses are in unfavorable positions, it modifies acceleration parameters to avoid critical speeds or adjusts balance ring configuration to create favorable phase relationships, thereby enabling productive acceleration without container-tub contact.
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 solution reduces the likelihood of container-tub contact during critical speeds, extends appliance lifespan, and allows for larger drum sizes without increasing the appliance's size, by optimizing the ramping process from low to high speed rotation based on real-time imbalance monitoring.
Implementation Method 1
at least one balance ring mounted to the drum and defining an internal annular cavity in which a mass is located
Implementation Method 2
a controller configured to determine, during the measurement period, at least one of a torque of the motor, an acceleration of the drum, a rotational speed of the drum, or an angular position of the drum
Data Source
AI summary
Apparatus and 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.