Washing Machine Clutch Engagement via Motor Stop-Time Feedback
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Solution Overview
Problem
Conventional washing machines require a magnet and location sensor to ensure correct clutch engagement between the pulsator and spin-drying tub, leading to increased costs and potential damage due to friction noise when engagement is incorrect.
Innovation Solution
A control device that aligns the coupling with a rotation preventing unit, applies different voltages to rotate the coupling at varying speeds, and examines the stop time to determine correct engagement, re-executing the engagement operation if necessary without using a magnet or location sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a magnet and location sensor are used to ensure correct clutch engagement, then the reliability of clutch engagement is improved, but the manufacturing cost increases
Solution Approach 1:
The patent removes the magnet and location sensor from the clutch engagement detection system. Instead of using these separate components, the invention uses the existing driving motor's rotation characteristics (stop time measurement) to determine engagement status, thereby eliminating unnecessary components and reducing manufacturing cost while maintaining reliability
Solution Approach 2:
The system uses the driving motor's own rotation and stopping characteristics to detect clutch engagement. By measuring how long the motor takes to stop after being turned off, the system self-determines engagement status without requiring external sensors or magnets, making the system self-sufficient and cost-effective
2Ease of manufacture
If no magnet and location sensor are used to reduce cost, then manufacturing cost decreases, but the measurement precision of clutch engagement status deteriorates
Solution Approach 1:
The system implements a feedback mechanism by measuring the stop time of the driving motor and using this information to determine clutch engagement status. The control device continuously monitors the stop time and compares it against predetermined thresholds to accurately detect whether engagement has occurred, providing precise measurement without additional sensors
Solution Approach 2:
The invention changes the detection parameter from magnetic field sensing (requiring magnets and sensors) to temporal parameter measurement (stop time). By measuring the time it takes for the motor to stop rotating after being turned off, the system achieves precise engagement detection using a different physical parameter that doesn't require expensive components
3Productivity
If the driving motor operates at high speed continuously, then productivity increases, but the risk of incorrect clutch engagement and resulting damage increases
Solution Approach 1:
The system performs a preliminary engagement check before starting the washing operation by measuring the stop time of the driving motor. This preliminary action ensures the clutch is correctly engaged before high-speed operation begins, preventing tooth form damage and friction noise that would occur if engagement were incorrect during operation
Solution Approach 2:
The patent implements a quick stop time measurement method that rapidly determines engagement status without prolonged testing. By measuring how long the motor takes to stop naturally after being turned off, the system quickly verifies engagement correctness before proceeding to high-speed washing, minimizing the time the system is in a potentially harmful state
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 reduces manufacturing costs and prevents quality failures by ensuring correct clutch engagement without the need for a magnet and location sensor, thereby minimizing damage and noise.
Implementation Method 1
rotate the driving motor by applying a voltage to a stator corresponding to the q-axis so that a magnetic field is formed along the q-axis, and rotate the driving motor right and left at a low speed when performing a washing operation by applying a voltage to a stator corresponding to the d-axis so that a magnetic field is formed along the d-axis
Data Source
Figure 1
Figure 2(a)~3
Figure 4~5
AI summary
A washing machine and a method for controlling a washing machine are provided. The washing machine (90) includes a washing spindle (150) and a spin-drying spindle (160), a coupling (144) that is movable to be engaged with a rotation preventing unit (146) of the washing machine so that power of the driving motor is transferred to the washing spindle but not to the spin-drying spindle, and is movable to a position in which the coupling is not engaged with the rotation preventing unit so that power of the driving motor is transferred to both the washing spindle and the spin-drying spindle, and a control device (170) configured to, in a washing mode of the washing machine, bring the coupling into contact with the rotation preventing unit, cause the coupling to rotate in first and second directions so that the coupling is engaged with the rotation preventing unit, and determine an engagement state by test-operating the driving motor.