Direct-Drive Washing Machine Tub Support for Simpler Motor Assembly
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Solution Overview
Problem
Existing washing machine direct drive systems are complex to install and have reliability and safety issues due to the high number of components and concentration of mechanical loads, making them difficult to assemble and produce.
Innovation Solution
A simplified direct drive system for washing machines using a plastic tub with a metal hub and disc-shaped plastic support, where the rotor and stator are mounted with fewer components, including roller bearings and friction welding, reducing the complexity and number of parts, and improving assembly and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple supports (cup-shaped external support and cup-shaped internal auxiliary support) are fastened to the tub for mounting the direct drive motor, then the motor system can be installed, but the installation process becomes complex and the number of components increases
Solution Approach 1:
The patent combines the external support and internal auxiliary support into a single integrated support structure. This unified support is directly mounted to the tub and provides all necessary mounting functions for the direct drive motor, eliminating the need for multiple separate supports and simplifying the installation process while maintaining structural reliability
2Ease of manufacture
If all mechanical loads of the drum are supported by an outside component (disc-shaped motor) fixed on the rear face of the tub, then the motor components can be kept together, but the concentration of forces in the fastening area creates reliability and safety problems
Solution Approach 1:
The patent segments the load support function across multiple structural elements: the integrated support structure mounted to the tub, the shaft extending through the drum, and the drum support bearing assembly. This distribution of load paths prevents concentration of forces in a single fastening area, reducing stress concentrations and improving reliability while maintaining ease of motor assembly
3Reliability
If a metal hub with annular flange and cup-shaped supports are used for mounting bearings, then the direct drive motor can be installed, but the number of components increases and installation cost increases
Solution Approach 1:
The patent integrates the bearing mounting functions into the unified support structure, eliminating the need for separate metal hubs with annular flanges and multiple cup-shaped supports. The integrated design provides all necessary bearing mounting surfaces and structural support in a single component, reducing part count and simplifying assembly while maintaining reliable bearing installation
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 solution results in a more straightforward installation process, reduced costs, and enhanced reliability by minimizing the number of components and distributing mechanical loads more evenly, making the appliance easier to assemble and produce.
Implementation Method 1
the flange 22a of a disc-shaped plastic support part 22 is fixed by means of friction welding
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A washing machine with a direct drive system comprises a tub, a drum rotating inside the tub, a shaft connected to the drum for transmission of a driving force of a direct drive motor, a coaxial support connected to a rear portion of the tub and having a seat for a first bearing supporting an end of the shaft opposite the drum, a stator restrained by the coaxial support and having a plurality of magnetic cores, a rotor provided with permanent magnets and connected to the shaft, a second bearing for supporting a portion of the shaft between its end and the drum, the tub (12) being made of polymeric material and being provided with a hub-shaped metal seat for the second bearing (18) which is co-moulded with the tub.