Dishwasher Drain Pump Chopper Assembly for Low-Noise Soil Maceration
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Solution Overview
Problem
Dishwashers with integrated chopper blades in wash pumps generate excessive noise due to the need for high torque to macerate soil particles, and adding a second drain pump increases size and noise, while existing designs struggle with proper alignment and leakage in the chopper assembly.
Innovation Solution
A low-profile drain pump with a central hub and axially sliding drive mechanism ensures proper alignment of the chopper blade relative to the apertured plate, allowing it to pivot and deflect around large particles, and oscillate to break them down without stalling, while minimizing leakage points through a one-piece housing design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a synchronous motor is used in a smaller drain pump, then the pump size is reduced, but the torque is insufficient causing the pump to stall when encountering hard or large soil particles
Solution Approach 1:
The chopper blade is designed to pivot on spindles rather than being rigidly fixed, allowing it to dynamically adjust its position when encountering hard or large soil particles. This pivoting action prevents the blade from becoming jammed and causing motor stall, while still effectively macerating particles during normal operation. The dynamic pivoting mechanism resolves the contradiction between using a small pump and maintaining reliable operation.
2Manufacturing precision
If the chopper blade is rigidly fixed to the drive shaft, then the blade maintains stable position, but the blade becomes jammed when encountering hard or large soil particles
Solution Approach 1:
The chopper blade is mounted on spindles that allow it to pivot freely during rotation. This dynamic mounting enables the blade to automatically adjust its position when encountering resistance from hard or large particles, preventing jamming and allowing continuous operation without interruption for blade replacement or motor repair.
3Reliability
If a one-piece housing is used for the drain pump, then the number of leakage points is minimized, but the alignment of the chopper blade relative to the apertured plate becomes difficult to control
Solution Approach 1:
The pump housing is divided into multiple segments or pieces that can be assembled together. This segmentation allows for precise alignment features to be built into the separate housing pieces, ensuring proper positioning of the chopper blade relative to the apertured plate. At the same time, the housing segments can be designed with integrated sealing features that maintain reliability while accommodating the precision alignment requirements.
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 reduces noise and size by enabling efficient maceration of soil particles with reduced torque requirements, ensuring proper alignment and minimizing leakage, thus enhancing the performance and quiet operation of dishwashers.
Implementation Method 1
a synchronous motor adapted to rotate the impeller and chopper blade
Implementation Method 2
The impeller has a plurality of vanes that extend radially outward from a central recess portion so that, upon rotation of the impeller, a flow of washing fluid is established
Implementation Method 3
the chopper blade repeatedly impacts the large/hard soil particle
Implementation Method 4
the chopper blade can become jammed or could come in contact with and abrade the chopper plate
Data Source
AI summary
A dishwasher includes a drain pump assembly having a chopper assembly coupled to an impeller and driven by a synchronous motor. The chopper assembly includes an impeller housing that includes a central hub portion for pivotally supporting a plurality of rotatable chopper blades. An apertured plate is secured to the impeller housing and maintained in a spaced relationship from the chopper blades. The chopper assembly is coupled to the impeller through an axially sliding drive mechanism that facilitates assembly of the chopper assembly into the impeller housing. The synchronous motor drives the chopper blade in a first direction until encountering a hard soil particle whereupon the chopper blades can pivot so that the chopper assembly can continue to operate or, if the chopper blade becomes jammed, the synchronous motor can oscillate to hammer the hard soil particle until it becomes small enough to pass through the apertured plate.