Drum Washing Machine Planetary Gear Drive for Seamless Mode Switching
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Solution Overview
Problem
Current drum washing machines face issues with increased weight and volume due to solenoid clutches, difficult wiring, noise generation, and low durability in spin-drying mode due to axial movement of deceleration coupling units and single bearing support, which affect operational efficiency and space efficiency.
Innovation Solution
The drum washing machine incorporates a planetary gear set that is spline-coupled to both the rotor and output shafts, with an actuator moving the gear set horizontally, and uses helical gears to increase safety and reduce noise, while being supported by two bearings for improved stability and reduced length, allowing seamless mode transitions without stopping the motor.
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 at low speed and high torque (washing mode) or high speed and low torque (spin-drying mode), but the weight and volume of the solenoid clutch increases
Solution Approach 1:
The patent replaces the solenoid clutch (electromagnetic system) with a mechanical clutch that uses a spring and lever mechanism. The spring provides the necessary force to engage and disengage the clutch without requiring an electromagnetic coil, thereby eliminating the weight and volume associated with the solenoid while maintaining the gear ratio changing capability between washing mode (n:1) and spin-drying mode (1:1).
2Adaptability or versatility
If a solenoid clutch is positioned behind the rotor and stator, then the gear ratio can be changed, 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 side of the rotor, utilizing previously underutilized spatial dimensions. This lateral placement allows the clutch to engage the sun gear without interfering with the axial space between rotor and stator, improving overall space efficiency and eliminating the need for complex wiring through the rotor-stator assembly.
3Adaptability or versatility
If a deceleration coupling unit moves axially to change gear ratio, then the washing machine can switch between modes, but noise is generated due to use of spur gears and the motor must be stopped for mode conversion
Solution Approach 1:
The patent replaces the spur gears with helical gears, which have curved tooth surfaces that engage gradually rather than abruptly. This curved geometry allows for smoother power transmission and reduces impact noise and vibration during gear engagement, while the planetary gear set maintains the ability to switch between washing mode (n:1 gear ratio) and spin-drying mode (1:1 gear ratio) without stopping the motor.
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 design reduces part tolerance and cost, enhances space efficiency, increases gear safety, reduces noise, and improves rotational stability by allowing continuous mode transitions and efficient heat dissipation, addressing the limitations of existing systems.
Implementation Method 1
a planetary gear set that a part of the planetary gear set is spline-coupled to the rotor shaft, and other part of the planetary gear set is spline-coupled to the output shaft
Implementation Method 2
an actuator moving the planetary gear set in a horizontal direction
Implementation Method 3
uses helical gears to increase safety and reduce noise
Implementation Method 4
being supported by two bearings for improved stability
Data Source
AI summary
A drum washing machine includes an inner tub and a drive system coupled to the inner tub. The drive system includes a housing, a motor disposed on one side of the housing, a rotor shaft coupled to the motor and bearing-coupled to the housing, an output shaft bearing-coupled to the housing, and wherein at least part of the output shaft is disposed in the rotor shaft, a planetary gear set that a part of the planetary gear set is spline-coupled to the rotor shaft, and other part of the planetary gear set is spline-coupled to the output shaft, and an actuator moving the planetary gear set in a horizontal direction, wherein, the housing is integrally formed with the inner tub.