Wet Rotor Pump Assembly Heat Dissipation and Alignment
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Solution Overview
Problem
Existing wet rotor pumps for house heating systems face challenges in achieving a compact design while maintaining efficient pumping and heat dissipation, as well as precise alignment of rotor and stator components, which affects efficiency and space usage.
Innovation Solution
The pump assembly incorporates a rotor axle with an impeller, a pump housing, a drive motor with a stator and rotor, and an electronics housing with a heat-conductive cap for improved heat dissipation and a bearing retainer system for precise alignment, allowing for a more compact configuration and enhanced efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a compact design is pursued by reducing the size of the rotor can and eliminating circumferential trunnions, then the lateral space requirement is reduced, but the alignment precision between rotor and stator components deteriorates
Solution Approach 1:
A centering sleeve is introduced as an intermediary component between the rotor can and the pump housing. This sleeve receives the rotor can and provides a centering function through its interaction with the pump housing, thereby maintaining alignment precision without requiring a large rotor can or circumferential trunnions. The centering sleeve acts as a mediator that transfers and maintains the geometric relationship between components.
Solution Approach 2:
The alignment function is segmented from the rotor can itself and assigned to a separate centering sleeve component. This allows the rotor can to be minimized in size while the centering sleeve handles the alignment task, resolving the contradiction between compact size and alignment precision.
2Volume of moving object
If the rotor can is minimized in size to achieve compactness, then lateral space is reduced, but the structural stability and centering capability deteriorate
Solution Approach 1:
The centering sleeve serves as a mediator that provides the centering capability without requiring the rotor can to be large. The sleeve is configured to receive the rotor can and provides geometric constraints that ensure proper centering and stability.
Solution Approach 2:
The centering function is extracted from the rotor can structure itself and placed into a separate centering sleeve component. This allows the rotor can to be minimized while the extracted centering function is performed by the sleeve.
3Temperature
If heat-conductive material is used for the cap, then heat dissipation from electronic components is improved, but the electrical insulation and flame retardancy deteriorate
Solution Approach 1:
The cap is constructed as a composite structure with an inner layer of heat-conductive material (such as aluminum) and an outer layer of electrically insulating and flame-retardant material (such as polyamide or PPS). This composite structure simultaneously achieves heat dissipation through the inner layer while maintaining electrical insulation and flame retardancy through the outer layer.
Solution Approach 2:
Different regions of the cap have different material properties: the inner surface facing the electronic components uses heat-conductive material for thermal management, while the outer surface uses insulating and flame-retardant material for safety. This local differentiation of material quality resolves the contradiction between heat dissipation and safety 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 results in a more compact and efficient pump design with improved heat dissipation and alignment, reducing fluid leakage and enhancing pumping efficiency by minimizing the gap between the impeller and neck ring, thus improving overall performance.
Implementation Method 1
the first material of the cap is at least partially overloaded with a second material at an inner side of the cap, wherein the second material is more heat-conductive than the first material
Data Source
AI summary
A pump assembly (1) includes a rotor axle (45) extending along a rotor axis (R), an impeller (12) fixed to the rotor axle (45), a pump housing (11) accommodating the impeller (12), and a drive motor with a stator (17) and a rotor (51). The rotor (51) is fixed to the rotor axle (45) for driving the impeller (12). A rotor can (57) accommodates the rotor (51). The rotor can (57) includes a rotor can flange (63). An electronics housing (13) has a cap (21) including a first material (139) forming a front face (19) of the cap (21). The front face (19) extends essentially perpendicular to the rotor axis (R). The first material (139) is at least partially overmolded with a second material (141) at an inner side of the cap (21). The second material (141) is more heat-conductive than the first material (139).