Drive system of a washing machine
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Solution Overview
Problem
Existing drive systems for washing machines face challenges in efficiently transitioning between washing and spin-drying modes without stopping operations, while also ensuring low-speed high-torque and high-speed low-torque operations with adequate durability and space efficiency.
Innovation Solution
The drive system incorporates a planetary gear set that can be moved without stopping to switch between washing and spin-drying modes, utilizing a sun gear spline-coupled to the rotor shaft, pinion gears, a ring gear, and carriers to achieve gear ratios of n:1 and 1:1, respectively, while using helical gears to enhance safety and reduce noise.
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 or high speed and low torque, 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 system that uses spring force and centrifugal force to engage and disengage clutch plates. This mechanical substitution eliminates the need for heavy electromagnetic coils while achieving the same gear ratio switching function between washing mode (n:1) and spin-drying mode (1:1).
Solution Approach 2:
The patent changes the operating parameters of the clutch system by using variable spring force and centrifugal force based on rotational speed to control clutch engagement. The spring force provides engagement at low speeds (washing mode) while centrifugal force overcomes the spring force at high speeds (spin-drying mode), enabling automatic gear ratio switching without heavy electromagnetic components.
2Adaptability or versatility
If a solenoid clutch is positioned behind the rotor and stator, then gear ratio can be changed, but it is disadvantageous to secure the volume of the washing machine and wiring becomes difficult
Solution Approach 1:
The patent repositions the clutch system from a location behind the rotor and stator (axial direction) to a location on the side of the rotor (radial direction). This dimensional change in positioning allows the clutch mechanism to be integrated into the side space of the motor assembly, freeing up the axial space that was previously occupied and simplifying the overall structure.
Solution Approach 2:
The patent merges the clutch system with the motor assembly by positioning it on the side of the rotor and integrating it with the existing motor structure. This consolidation eliminates the need for separate wiring circuits and control systems, reducing the overall volume requirements and simplifying the drive system architecture.
3Device complexity
If the planetary gear set is not moved, then the structure is simpler, but the motor must be stopped for mode conversion between washing and spin-drying
Solution Approach 1:
The patent introduces a movable planetary gear set that can dynamically shift position along the output shaft axis. The gear set moves to different axial positions to engage different clutch plates (first clutch plate for washing mode, second clutch plate for spin-drying mode), enabling continuous operation without motor stopping. This dynamic positioning capability maintains structural relative simplicity while achieving high productivity through seamless mode transitions.
4Device complexity
If only one bearing supports the output shaft, then the structure is simpler, but the durability decreases during spin-drying mode operation
Solution Approach 1:
The patent segments the support function for the output shaft by introducing a second bearing in addition to the first bearing. The first bearing supports the output shaft at one location while the second bearing provides support at another location, creating a distributed support system that enhances durability during high-speed spin-drying operation without significantly complicating the overall structure.
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 solution enables seamless mode transitions without stopping, improves rotational stability, reduces noise, and increases space efficiency by allowing the entire planetary gear set to be moved vertically, thus preventing part damage from differing rotational speeds.
Implementation Method 1
a planetary gear set and a clutch, and operates an output shaft at low speed and high torque with a gear ratio of n: 1 (washing mode), or operates the output shaft at high speed and low torque with a gear ratio of 1:1 (spin-drying mode)
Implementation Method 2
using helical gears to enhance safety and reduce noise
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A drive system of a washing machine comprising a housing (120), a motor (190) disposed on one side of the housing (120), a rotor shaft (170) coupled to the motor (190) and bearing-coupled to the housing (120), an output shaft (110) at least part of which is disposed within the rotor shaft (170), and bearing-coupled to the housing (120), a planetary gear set (200) a part of which is spline-coupled to the rotor shaft (170), and other part of which is spline-coupled to the output shaft (110), and an actuator moving the planetary gear set (200) in a vertical direction, wherein when the planetary gear set (200) is moved to one side, a part of the planetary gear set is coupled to the rotor shaft (170) to transmit a rotational force of the rotor shaft to the output shaft (110) at a ratio of 1:1, and when the planetary gear set (200) is moved to other side, another part of the planetary gear set (200) is coupled to the housing (120) to reduce the rotational force of the rotor shaft at a gear ratio of n:1 and transmit it to the output shaft (110).