Washing Machine Planetary Gear Drive for Vertical Mode Switching
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Solution Overview
Problem
Existing washing machine drive systems face issues with increased weight and volume due to large coils in solenoid clutches, difficult wiring, noise generation from spur gears, low durability from single bearing support, and inefficient space utilization during mode transitions.
Innovation Solution
A drive system with a planetary gear set that moves vertically to switch between low-speed high-torque and high-speed low-torque modes without stopping, using helical gears for reduced noise, two bearings for stability, and spline couplings for synchronized gear movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a solenoid clutch is used to change gear ratio, then the washing machine can operate in different modes (washing and spin-drying), but the weight and volume of the solenoid clutch increases due to larger coils required for sufficient electromagnetic force
Solution Approach 1:
The patent replaces the electromagnetic solenoid clutch with a purely mechanical clutch mechanism that uses a pressing member to engage and disengage clutch plates. This mechanical system eliminates the need for large electromagnetic coils, significantly reducing the weight and volume of the clutch assembly while maintaining the ability to switch between washing mode (n:1 gear ratio) and spin-drying mode (1:1 gear ratio)
2Device complexity
If a solenoid clutch is positioned behind the rotor and stator, then the clutch can be integrated into the drive system, but it is disadvantageous to secure the volume of the washing machine and requires difficult wiring work
Solution Approach 1:
The patent repositions the clutch mechanism from a location behind the rotor and stator to the front side of the rotor, where it can be integrated with the planetary gear set in a more space-efficient arrangement. The pressing member is positioned to press against the clutch plate in a direction that optimizes space utilization, allowing the clutch to be compactly integrated without requiring additional wiring channels or increasing the overall volume of the washing machine
3Device complexity
If spur gears are used in the planetary gear set, then the structure is simple, but noise is generated during operation
Solution Approach 1:
The patent changes the gear type from spur gears to helical gears in the planetary gear set. Helical gears have angled teeth that engage gradually rather than abruptly, which significantly reduces noise and vibration during operation. This parameter change in gear geometry maintains the simplicity of the planetary gear structure while effectively eliminating the noise problem associated with spur gears
4Device complexity
If the output shaft is supported by only one bearing, then the structure is simple, but the durability is reduced during spin-drying mode operation at high speed
Solution Approach 1:
The patent divides the output shaft support into two separate bearings instead of using a single bearing. The first bearing supports the output shaft at one location while the second bearing supports it at another location. This segmentation of the support function provides better load distribution and stability, significantly improving the durability and reliability of the output shaft during high-speed spin-drying operation without substantially increasing structural complexity
Data Source
AI summary
A drive system of a washing machine includes a housing, a motor, a rotor shaft coupled to the motor and the housing, an output shaft having a part within the rotor shaft and coupled to the housing, a planetary gear set coupled to the rotor shaft and the output shaft, and an actuator configured to move the planetary gear set in a vertical direction. When the planetary gear set is moved to one side, a part of the planetary gear set is coupled to the rotor shaft to transmit a rotational force of the rotor shaft to the output shaft at a ratio of 1:1. When the planetary gear set is moved to other side, another part of the planetary gear set is coupled to the housing to reduce the rotational force of the rotor shaft at a gear ratio of n:1 and transmit it to the output shaft.