Dishwasher Pump Assembly Mass Damping for Broad Vibration Reduction
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Solution Overview
Problem
Existing dishwasher noise reduction methods are costly, complex, and require frequent re-tuning, while they fail to effectively dampen vibrations across a broad frequency range, leading to ongoing noise issues from pump and motor operations.
Innovation Solution
A mass damper is rigidly fixed to the dishwasher pump assembly's housing, offset from the pump and motor unit, providing additional weight and conforming to the sump enclosure shape to stabilize the center of gravity and reduce vibrations across a wide frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If freely oscillating mass components are attached to motor via elastic linkage components, then motor vibrations are damped, but the arrangement becomes complicated and expensive to produce
Solution Approach 1:
The invention extracts the mass component from the motor assembly and places it separately on the pump housing. This eliminates the need for elastic linkages and complex mounting mechanisms, while still achieving vibration damping through the separate mass's interaction with the housing structure.
Solution Approach 2:
The pump housing serves as an intermediary structure that couples the mass component to the motor assembly. Instead of directly attaching the mass to the motor via complex elastic linkages, the housing mediates the connection, simplifying the overall arrangement while maintaining vibration damping effectiveness.
2Object-affected harmful factors
If oscillating mass components are tuned to specific resonant frequency, then motor vibrations are effectively damped, but re-tuning is required over time to remain effective
Solution Approach 1:
The invention creates a dynamic vibration damping system where the mass component interacts with the pump housing's natural frequencies. Rather than requiring precise static tuning to a single frequency, the system adapts to various operating conditions and frequency ranges, eliminating the need for re-tuning over time.
Solution Approach 2:
The system exploits changes in operational parameters (flow rates, speeds, loads) to achieve vibration damping across multiple frequency ranges. The mass component's interaction with the housing varies dynamically with operating conditions, providing broad-spectrum damping without requiring adjustment or re-tuning.
3Object-affected harmful factors
If mass damper is positioned offset from pump and motor unit, then center of gravity is stabilized and vibrations are reduced, but the mass damper occupies additional space on the housing
Solution Approach 1:
The pump housing serves multiple functions: it contains the pump and motor assembly, provides structural support, acts as a mounting surface for the mass damper, and serves as part of the vibration damping system itself. This multi-functionality allows the mass damper to be integrated into the existing housing structure without requiring additional dedicated space.
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 mass damper significantly reduces vibrations and noise levels, maintaining noise below 50 decibels, with a 10-20% reduction in specific operational stages, providing a cost-effective and robust noise reduction solution.
Implementation Method 1
The mass damper provides added weight to the pump assembly which reduces vibrations throughout the dishwasher caused by operation of the pump and motor unit
Data Source
AI summary
A dishwasher incorporates a dampened pump assembly including a housing having a base to which is mounted a pump and motor unit configured to develop a flow of washing fluid during operation of the dishwasher. A mass damper is mounted to the housing, with the mass damper substantially conforming to the shape, directly abutting and being rigidly fixed to a portion of the housing at a position offset from the pump and motor unit. The mass damper provides added weight, generally in the order of 1-6 lbs, to the pump assembly which reduces vibrations throughout the dishwasher caused by operation of the pump and motor unit.