Dual-Drum Washing Machine for 3D Laundry Motion
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Solution Overview
Problem
Conventional drum-type washing machines limit laundry motion to two-dimensional circumferential motion, leading to inefficient washing, increased washing time, and entanglement issues, which result in wrinkles and difficulty in removing laundry.
Innovation Solution
A washing machine design featuring a main drum and a sub-drum that can rotate independently, allowing three-dimensional motion of laundry through relative rotations between the two drums, driven by a dual-rotor motor with a stator and outer rotor connected to the sub-drum and an inner rotor connected to the main drum, enabling axial and circumferential movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single drum is rotated to move the laundry, then the structure is simple, but the laundry is limited to two-dimensional circumferential motion without axial-direction motion
Solution Approach 1:
The washing drum is segmented into an inner drum and an outer drum that can rotate independently. The inner drum rotates in one direction while the outer drum rotates in the opposite direction, enabling complex three-dimensional laundry motion without requiring a single complex drum structure.
Solution Approach 2:
The inner drum is nested within the outer drum, with the inner drum having a smaller diameter and being positioned coaxially inside the outer drum. This nested configuration allows both drums to rotate independently while sharing the same space, enabling versatile laundry motion without excessive structural complexity.
2Productivity
If a single drum rotates the laundry in circumferential direction only, then the drum structure is simple, but the washing effect is limited and washing time increases
Solution Approach 1:
The system dynamically controls the rotation of both inner and outer drums with different speeds and directions. During washing, both drums rotate at relatively low speeds in opposite directions to create gentle tumbling motion. During dehydration, the rotation speeds are increased while maintaining the counter-rotation pattern, optimizing performance for different operational phases.
Solution Approach 2:
The washing machine employs periodic action by alternating between washing mode (low speed, both drums rotating) and dehydration mode (high speed, both drums rotating). The control unit switches between these modes based on the operational phase, creating periodic variations in rotation speed and direction that optimize both washing efficiency and dehydration performance.
3Productivity
If dehydration is performed using centrifugal force by drum rotation, then water removal is effective, but laundry becomes entangled and stuck on the inner circumferential surface
Solution Approach 1:
During dehydration, both the inner drum and outer drum rotate in opposite directions at high speeds. The counter-rotation creates a shearing effect that prevents laundry from sticking to the drum surface, reducing entanglement and wrinkles while maintaining effective centrifugal force for water removal.
4Ease of operation
If the laundry is moved only in circumferential direction along the inner circumferential surface, then the drum structure is simple, but the contact surfaces of laundry are not varied resulting in uneven washing
Solution Approach 1:
The system dynamically adjusts the rotation speeds of the inner and outer drums during the washing cycle. By varying the speed differential between the two drums, the laundry experiences changing motion patterns that promote uniform contact with water and detergent, ensuring even washing across all garment surfaces.
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
The independent rotation of the drums enhances washing efficiency by allowing three-dimensional motion, reducing washing time, preventing entanglement, and facilitating easy laundry removal, while optimizing torque distribution and mechanical forces applied to the laundry.
Implementation Method 1
The rotor teeth form magnetic fluxes with the stator so as for the rotor to have a rotational force
Implementation Method 2
The laundry is rotated along the inner circumferential surface of the drum by a centrifugal force responsive to the rotation of the drum
Implementation Method 3
a falling motion from an upper side of the drum by the force of gravity
Implementation Method 4
the friction against the inner circumferential surface of the drum
Data Source
AI summary
A washing machine includes a main body defining an outer appearance, a tub disposed within the main body, a main drum rotatably mounted in the tub, a sub drum mounted in the main drum to be relatively rotatable with respect to the main drum, an outer shaft for rotating the main drum, an inner shaft for rotating the sub drum, being disposed inside the outer shaft, and a driving motor having a stator, an outer rotor connected to the inner shaft that is rotatable outside the stator, and an inner rotor connected to the outer shaft that is rotatable inside the stator, wherein the driving motor independently drives the main drum and the sub drum.