Washing Machine Bearing Force Monitoring Using Tub Motion Detection
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Solution Overview
Problem
Existing washing machine technologies face challenges in accurately monitoring and maintaining load balance during operation, leading to potential out-of-balance issues that cause noise, vibrations, and premature component failure, often requiring additional components and sensors that increase cost and complexity.
Innovation Solution
A method and apparatus that utilize a measurement device to determine bearing forces at the front and rear bearings based on basket speed and displacement amplitudes, comparing these forces to predetermined limits, and adjusting operating parameters, such as basket speed, to prevent excessive wear and maintain balance without the need for additional sensors or complex systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional monitoring systems using additional sensors and components are used to detect load balance, then detection capability is improved, but device complexity and cost increase
Solution Approach 1:
The washing machine uses its existing motor and motion sensors to monitor its own operation and detect load imbalance conditions. The system self-diagnoses by analyzing motor current patterns and tub motion characteristics during the spin cycle, eliminating the need for separate detection devices.
Solution Approach 2:
Existing components such as the motor and motion sensors are made to serve dual purposes: their primary functions plus load balance detection. The motor current monitoring system that controls spin speed also detects imbalance conditions, and the tub motion sensor used for vibration control also identifies load distribution issues.
2Productivity
If high-speed rotation is maintained during spin cycle, then productivity is improved, but bearing wear and noise increase due to out-of-balance conditions
Solution Approach 1:
The system continuously monitors motor current and tub motion during the spin cycle, comparing actual values against expected ranges. When load imbalance is detected through abnormal current patterns or excessive tub motion, the controller provides feedback to reduce spin speed, preventing bearing damage while maintaining high speed during balanced conditions.
Solution Approach 2:
The spin speed is made dynamic rather than fixed, automatically adjusting based on real-time load balance conditions. The system transitions between high-speed operation (when balanced) and reduced-speed operation (when imbalanced), optimizing both productivity and component protection throughout the spin cycle.
Data Source
AI summary
A washing machine appliance includes a wash basket rotatably mounted within a wash tub and supported by a front bearing and a rear bearing. A method of operating the washing machine appliance includes rotating the wash basket within the wash tub at a basket speed and obtaining first and second displacement amplitudes of the wash tub. Bearing forces at the front and rear bearings are obtained based on the basket speed and the displacement amplitudes. The determined bearing force at the front bearing is compared to a front limit. The determined bearing force at the rear bearing is compared to a rear limit. If the determined bearing force value at either of the front bearing or the rear bearing is greater than or equal to the respective limit, an operating parameter of the washing machine appliance is adjusted to limit bearing forces resulting from out-of-balance loads.