Laundry Drum Speed Control Using Vibration-Based Wash Mechanics
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Solution Overview
Problem
Existing laundry drum speed control methods fail to optimize washing mechanics for varying loads and wash programs, resulting in inadequate cleaning effects, especially with large loads where mechanical washing is reduced due to rolling movements and lack of friction between laundry items.
Innovation Solution
A method that determines optimal target speeds below the contact speed by measuring oscillating system movements at different speeds, comparing these values to find the highest mechanical effect, and adjusting the drum speed accordingly to maximize washing mechanics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the laundry drum is operated at speeds significantly below the contact speed, then water absorption and flow through the laundry is improved, but the mechanical washing effect is significantly reduced due to rolling movement
Solution Approach 1:
The patent applies dynamics by continuously varying the drum speed during the washing cycle rather than maintaining a fixed speed. The control element adjusts the rotational speed dynamically based on the washing phase, alternating between speeds below contact speed (for water absorption) and speeds above contact speed (for mechanical washing), thereby resolving the contradiction between water flow and mechanical washing effects
Solution Approach 2:
The patent implements periodic action by alternating between different speed phases during the washing cycle. The drum is operated in cycles: first at speeds below contact speed for water absorption, then at speeds above contact speed for mechanical washing, creating a periodic pattern that combines both beneficial effects and eliminates the harm of reduced mechanical washing
2Object-generated harmful factors
If the laundry drum is driven above the contact speed, then mechanical washing is enhanced through compression and friction, but water absorption and flow through the laundry is reduced
Solution Approach 1:
The control element dynamically adjusts the drum speed based on the required washing function. When mechanical washing is the priority, the speed is increased above contact speed to generate compression and friction. When water absorption is needed, the speed is reduced below contact speed. This dynamic adjustment resolves the contradiction by allowing both speed regimes to be utilized appropriately
Solution Approach 2:
The washing cycle incorporates periodic alternation between high-speed phases (above contact speed for mechanical washing) and low-speed phases (below contact speed for water absorption). This periodic switching ensures that neither effect dominates exclusively, thereby resolving the contradiction between enhanced mechanical washing and reduced water flow
3Device complexity
If fixed speeds are used for washing, then the control system is simple, but the washing mechanics cannot be optimized for varying loads and wash programs
Solution Approach 1:
The patent employs feedback by using a control element that monitors washing conditions and adjusts the drum speed accordingly. The control system receives information about the washing state and modifies the rotational speed in real-time to optimize mechanical washing effects for different loads and programs, thereby achieving adaptability without excessive complexity
Solution Approach 2:
The control element changes the operational parameters (rotational speed) based on the detected washing conditions and program requirements. By adjusting the speed parameter dynamically rather than using fixed speeds, the system achieves optimization for varying loads while maintaining relatively simple control logic
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 method ensures the laundry drum operates at the speed that maximizes mechanical action on laundry, enhancing the cleaning effect by optimizing the washing mechanics for any load and wash program, thereby improving the overall washing performance.
Implementation Method 1
measuring an oscillating system movement value (s1 to sx) at each target speed (n1 to nx)
Implementation Method 2
the so-called contact speed at which the laundry is pressed against the drum wall by centrifugal force
Data Source
AI summary
The invention relates to a method for determining a target rotational speed (n) below an application rotational speed of a washing drum (2) of a laundry treatment device (1) having a drive (16) and a vibrating system (10), wherein a dependence of a mechanical effect on items to be washed (3) located in the washing drum (2) on the respective nominal speed (n) of the washing drum (2) is used to ascertain the target rotational speed (n) at which the mechanical effect is at the greatest. The mechanical effect at a respective target rotational speed is ascertained by measuring vibrating system movements of the vibrating system (10) which exhibit greater frequency than the respective target rotational speed. The rotational speed at which the maximum vibrating system movement was measured is selected for carrying out the washing care procedure. The advantage of such a method is that the washing mechanics can be increased, thus improving the cleaning efficiency.