Stepped Auger Vane Structure for Low-Energy Washing Agitators
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Solution Overview
Problem
Existing washing machine agitator designs face issues with thick roots in auger vanes, leading to increased material usage, long cycle times, mold warpage, and reduced washing efficiency due to high mechanical energy requirements and friction losses, which strain the motor and result in high energy consumption.
Innovation Solution
The agitator assembly features a tubular body with a vane that tapers from a root to a tip at a draft angle of less than 12 degrees, with a ratio of vane width to root thickness greater than 4, and an undercut angle between 50 to 75 degrees, allowing for a larger vane width and thinner root, reducing material usage and energy consumption while maintaining effective washing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the undercut angle and pitch are selected to achieve desired auger performance, then washing performance is improved, but the draft angle increases resulting in a thick root and shorter vane width
Solution Approach 1:
The auger vane is segmented into multiple ledges connected by steps, transforming the continuous spiral into a discrete structure. This segmentation allows the vane to achieve the desired undercut angle and pitch for washing performance while maintaining a smaller draft angle, thus reducing root thickness and increasing vane width.
Solution Approach 2:
The invention introduces vertical steps between horizontal ledges, adding a vertical dimension to the vane structure. This dimensional change enables the vane to achieve the required spiral geometry and washing performance without relying solely on increased draft angle, thereby maintaining thinner roots and larger vane widths.
2Strength
If a thick root is used in the auger vane, then structural strength is improved, but material usage increases and cycle times become longer
Solution Approach 1:
The vane structure employs local quality by concentrating material where needed - the ledges provide structural strength at critical locations while the steps connect them vertically. This localized material distribution maintains necessary strength without requiring a uniformly thick root, thus reducing overall material usage and cycle times.
3Stability of the object's composition
If a thick root is used in the auger vane, then structural stability is improved, but mold warpage and sinks occur during manufacturing
Solution Approach 1:
Segmenting the vane into ledges and steps creates a structure with better cooling characteristics during injection molding. The segmented design allows more uniform heat distribution and solidification, preventing the warpage and sinks that occur with thick, continuous root structures.
4Productivity
If the vane width is increased to improve washing efficiency, then mechanical energy requirements decrease, but the draft angle must be reduced which increases root thickness
Solution Approach 1:
By introducing vertical steps between ledges, the invention enables increased vane width without increasing draft angle. The vertical dimension provided by the steps allows the horizontal ledges to extend further outward, improving washing efficiency while maintaining a thin root structure.
Data Source
AI summary
An agitator assembly for an automatic washing machine comprises an agitator and an auger mounted to the agitator. The auger comprises a tubular body defining a peripheral surface and having a central longitudinal axis. A vane spirals around the tubular body and extends from the peripheral surface from a root having a thickness T to a tip. The vane has a width W measured from the peripheral surface along a line perpendicular to the central longitudinal axis to the tip. The vane is formed by a plurality of ledges, with adjacent ledges joined by steps. With this configuration, the vane can have a relatively small root thickness T and a relatively large width W.