Nested Planetary Gear Assembly for Compact Washing Machine Drum Drive
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Solution Overview
Problem
Existing washing machine driving systems face challenges in achieving a compact design with a high reduction ratio while maintaining a large drum volume and efficient assembly process.
Innovation Solution
The washing machine driving system incorporates a planetary gear assembly with a carrier shaft fixedly supported on the drum shaft, a coupling shaft serration-coupled to the carrier shaft, and a sun gear rotationally supported on the coupling shaft, allowing for a compact design and high reduction ratio without affecting the drum volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the drum shaft diameter is increased to accommodate the planetary gear assembly, then the reduction ratio is improved, but the drum volume is reduced
Solution Approach 1:
The planetary gear assembly is nested within the hollow cylindrical space formed by the drum shaft, allowing the gear components (sun gear, planet gears, carrier) to be positioned inside the drum shaft structure rather than requiring increased drum shaft diameter. This nesting approach maintains both high reduction ratio and large drum volume simultaneously.
2Power
If the planetary gear assembly and clutch assembly are arranged in series on the drum shaft axis, then the reduction ratio is improved, but the device complexity increases
Solution Approach 1:
The planetary gear assembly and clutch assembly are merged into a single integrated structure where the clutch is positioned within the planetary gear assembly's hollow space. The clutch's input shaft, output shaft, and engagement mechanisms share the same spatial envelope as the planetary gears, reducing the number of separate components and simplifying the overall assembly process while maintaining the high reduction ratio.
3Power
If the sun gear diameter is increased to achieve high reduction ratio, then the power transmission is improved, but the assembly process becomes more difficult
Solution Approach 1:
The planetary gear assembly is divided into modular segments: the sun gear is separated from the drum shaft, the planet gears are mounted on a removable carrier, and the clutch components are positioned within the hollow drum shaft. This segmentation allows each component to be manufactured and assembled independently, then combined as a complete unit, significantly easing the assembly process while maintaining effective power transmission through the gear meshing.
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 configuration enables a compact and efficient washing machine driving system that maximizes drum volume, achieves a high reduction ratio, and improves assembly efficiency, all while using a small motor.
Implementation Method 1
a planetary gear assembly (300)
Implementation Method 2
a clutch assembly (400)
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A planetary gear assembly included in a washing machine driving system according to an embodiment of the present disclosure, may include a carrier shaft fixedly supported on a back end of a drum shaft by a first fastening member; a coupling shaft including a first shaft portion inserted into the carrier shaft and a first flange portion fixed to a back end of the carrier shaft by a second fastening member, and fixedly supported on the carrier shaft; a carrier including a second shaft portion inserted into the first shaft portion of the coupling shaft and a second flange portion positioned at a back side of the first flange portion of the coupling shaft, and fixedly supported on the coupling shaft; a sun gear rotationally supported on the coupling shaft and fixedly supported on a rotor frame of a motor by a third fastening member; a plurality of pinion gears coupled to the second flange portion of the carrier, and tooth-coupled with the sun gear; a ring gear tooth-coupled with the plurality of pinion gears; and a gear housing accommodating the sun gear, the plurality of pinion gears, and the ring gear therein. According to this configuration, since the sun gear, which is related to the reduction ratio of the planetary gear assembly, is coupled to the carrier coupled to the drum shaft, and the planetary gear assembly and the clutch are disposed in the inner space of the stator, it is possible to compact the washing machine driving system and to secure the maximum volume of the drum.