Eccentric Screw Pump Drive Wheel Rotor Integration
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Solution Overview
Problem
Eccentric screw pumps for household appliances, such as washing machines, require complex and costly drive systems to achieve the necessary two-dimensional movement of the rotor, making them unsuitable for use as metering pumps due to their complexity and associated costs.
Innovation Solution
A 2:1 hypocycloid progressing cavity pump design with a gear drive wheel and a cylindrical drive worm, where the pump rotor is mounted eccentrically on the drive wheel, allowing for a simple and cost-effective implementation of the two-dimensional movement required for fluid conveyance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional drive system is used to achieve two-dimensional movement of the rotor, then the required movement is achieved, but the device complexity and cost increase significantly
Solution Approach 1:
The pump rotor is merged with the drive wheel into a single integrated component. The drive wheel itself is shaped to generate the required two-dimensional hypocycloid motion when rotated by a simple single-axis motor, eliminating the need for separate mechanisms to achieve eccentric movement.
Solution Approach 2:
The drive wheel serves multiple functions simultaneously: it acts as the driving element transmitted by the motor, the structural component that generates eccentric motion through its geometry, and the mounting base for the pump rotor. This multi-functionality reduces overall system complexity.
2Measurement precision
If a complex drive system is implemented, then precise metering is achieved, but the manufacturing cost increases
Solution Approach 1:
The integration of the drive wheel and pump rotor into one piece reduces the number of components that need to be manufactured, assembled, and precision-aligned. The single integrated component can be manufactured more economically while maintaining the precise geometric relationships required for accurate metering.
Solution Approach 2:
The invention changes the geometric parameters of the drive wheel (its circumference shape and eccentricity) to directly encode the required motion profile. By optimizing these geometric parameters, precise metering is achieved through the shape itself rather than through complex control systems or additional mechanical components.
3Ease of operation
If multiple moving parts are used, then the two-dimensional movement is achieved, but the reliability decreases due to more potential failure points
Solution Approach 1:
By merging the drive wheel and pump rotor into a single integrated moving component, the number of moving parts is reduced. This eliminates potential failure points at interfaces between separate components, such as bearings, couplings, or mounting mechanisms, thereby improving reliability.
Solution Approach 2:
The invention segments the pump into two main parts: a single integrated moving component (drive wheel with mounted rotor) and a stationary component (pump housing with stator). This segmentation isolates the complex two-dimensional motion into one well-defined moving assembly, simplifying the overall system and improving reliability.
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 provides a compact, cost-effective, and precise metering system with reduced component fatigue and assembly complexity, enabling efficient fluid handling while maintaining high dosing accuracy and fluid tightness.
Implementation Method 1
a 2:1 hypocycloid progressing cavity pump design with a gear drive wheel and a cylindrical drive worm
Implementation Method 2
the pump rotor is mounted eccentrically on the drive wheel, allowing for a simple and cost-effective implementation of the two-dimensional movement required for fluid conveyance
Implementation Method 3
the pump rotor is mounted eccentrically on the drive wheel in such a way that the longitudinal axis of the pump rotor runs at a distance R from the center point of the drive wheel
Implementation Method 4
Both the shape of the pump rotor and the corresponding shape of the pump stator have a periodicity along the longitudinal axis of the pump rotor
Data Source
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AI summary
The invention relates to an eccentric screw pump (100) comprising a pump rotor (107) and a pump stator (109), wherein the pump stator (109) defines a hollow space in which at least one part of the pump rotor (107) is rotatably arranged, and the pump rotor (107) is designed to be rotated by a drive wheel (103, 203) in order to convey a fluid, wherein the pump rotor (107) is eccentrically attached to the drive wheel (103, 203).