Washer Drum Speed Control for Spin Imbalance Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing washing machines face challenges in reducing imbalance during the spin cycle due to uneven distribution of laundry items on the drum's inner wall, leading to vibrations and unsatisfactory centrifugal results.
Innovation Solution
A method that dynamically adjusts the drum speed based on the degree of contact between laundry items and the inner wall, using measurements and control variables such as harmonic oscillations and displacement signals to determine the stability of the distribution, allowing for targeted speed changes to maintain or adjust the speed for optimal imbalance reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the drum speed is increased to improve centrifugal separation, then the centrifugal results improve, but the imbalance and vibrations increase due to uneven laundry distribution
Solution Approach 1:
The system performs preliminary laundry distribution at lower speeds before the spin cycle, using speed variations to redistribute laundry items and achieve more uniform distribution on the drum wall, thereby reducing imbalance before high-speed centrifugal operation begins
Solution Approach 2:
The drum speed is dynamically adjusted during the laundry distribution phase, alternating between increasing and decreasing speeds to prevent laundry items from settling in fixed positions, thereby promoting more uniform distribution and reducing imbalance
2Stability of the object's composition
If the drum speed is varied to redistribute laundry items, then the laundry distribution improves, but the spin cycle duration increases
Solution Approach 1:
The system applies speed variations only during the laundry distribution phase before the main spin cycle, rather than continuously during the entire spin cycle, thereby achieving sufficient redistribution without excessive time loss
Solution Approach 2:
The drum speed is varied periodically during the distribution phase with alternating acceleration and deceleration cycles, creating conditions for laundry redistribution while maintaining a structured time profile that limits overall duration
3Force
If the drum speed is increased to press laundry against the inner wall, then the centrifugal force increases, but the imbalance position becomes harder to control
Solution Approach 1:
The system establishes preliminary laundry distribution patterns at lower speeds where imbalance position can be more easily influenced, before transitioning to high-speed centrifugal operation where the laundry is already positioned favorably
Solution Approach 2:
The system changes the speed parameter dynamically during different phases: using lower speeds during distribution for controllability, and higher speeds during spin for centrifugal effect, thereby optimizing both control ease and centrifugal force
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 effectively reduces imbalance, minimizes vibrations, and ensures better distribution of laundry items, leading to improved centrifugal results and reduced noise, while allowing for increased drum filling volume and adaptability to different laundry loads.
Implementation Method 1
The drum of the washing machine rotates at a very high speed, for example at a speed of 1,200 rpm, so that the items of laundry can lie firmly against an inner wall of the drum
Implementation Method 2
Two forces act on the items of laundry in a rotating drum, namely the gravitational force and the centrifugal force
Implementation Method 3
Two forces act on the items of laundry in a rotating drum, namely the gravitational force and the centrifugal force
Data Source
Figure 1~2
Figure 3~4
Figure 5~7
AI summary
The invention relates to a method for operating a domestic appliance (1) for caring for laundry items (17), in which method, before a change to a spin mode, the laundry items (17) are distributed in a laundry distribution mode in an interior of a drum (2) of the domestic appliance (1) by raising and/or lowering a rotational speed (n) of the drum (2), wherein a degree (S) of the laundry items (17) bearing against an inner wall of the drum (2) is determined as a function of a measured variable and/or control variable (n, W), and the rotational speed (n) is raised and/or lowered and/or maintained on the basis of the degree (S) of the laundry items (17) bearing against the inner wall.