Integrally Molded Gear Pump Nozzle Sealing
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Solution Overview
Problem
Existing transverse internal gear pumps face issues with seal reliability due to thermal expansion differentials and manufacturing costs, particularly when using thermoplastic materials or pressed parts, and require high sealing properties for high-pressure applications like carbon dioxide refrigerant systems.
Innovation Solution
A transverse internal gear pump design featuring an integrally molded liquid intake nozzle and intake cover using a resin composition with polyphenylene sulfide resin and additives like glass fibers, secured with a retaining ring or elastically deforming engaging portions, which enhances sealing and reduces manufacturing steps and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If thermoplastic materials or pressed parts are used for the intake nozzle and cover, then manufacturing cost is reduced, but seal reliability deteriorates due to thermal expansion differentials
Solution Approach 1:
The patent combines the liquid intake nozzle and intake cover into a single integrally molded component made from thermoplastic material. This eliminates the separate parts that would require joining, thereby eliminating seal interfaces that are susceptible to thermal expansion differentials and sealing failures. The integration maintains manufacturing cost benefits while resolving the seal reliability issue.
Solution Approach 2:
The patent employs thermoplastic materials with specific properties (such as polyphenylene sulfide or polyether ether ketone) that provide both cost-effectiveness and sufficient thermal stability. These composite materials allow the integrally molded component to maintain dimensional stability across temperature variations while preserving the economic advantages of thermoplastic manufacturing.
2Adaptability or versatility
If separate parts are joined by plastic working or pressing, then manufacturing flexibility is improved, but seal reliability deteriorates and manufacturing complexity increases
Solution Approach 1:
The patent integrates the liquid intake nozzle and intake cover into one piece through injection molding, eliminating the need for separate parts and joining operations. This maintains manufacturing flexibility through the versatility of injection molding while completely eliminating seal reliability issues associated with joined separate parts.
3Adaptability or versatility
If separate parts are joined by plastic working or pressing, then manufacturing flexibility is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent combines multiple manufacturing steps and separate components into a single injection molding process. The integrally molded structure eliminates assembly operations, reduces part count, and simplifies manufacturing complexity while maintaining the flexibility to produce various configurations through mold design.
4Ease of manufacture
If thermoplastic materials are used, then manufacturing cost is reduced, but sealing performance deteriorates in high-pressure applications
Solution Approach 1:
The patent eliminates seal interfaces by integrating the nozzle and cover into one piece. This removes the vulnerability of thermoplastic materials to high-pressure sealing failures, as there are no separate sealing surfaces or joints where pressure could compromise the seal.
Solution Approach 2:
The patent selects high-performance thermoplastic materials (such as polyphenylene sulfide or polyether ether ketone) that inherently withstand high pressures while maintaining cost-effectiveness. These materials provide the necessary mechanical strength and pressure resistance without requiring additional sealing mechanisms.
Data Source
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AI summary
Provided is a transverse internal gear pump that can be manufactured at low cost, and also has a high safety factor in terms of functionality. This transverse internal gear pump 1 has a trochoid 4, in which an inner rotor 3 having a plurality of outer teeth is rotatably accommodated within an outer rotor 2 having a plurality of inner teeth, the inner rotor being rotatably accommodated within the outer rotor in an eccentric state and with the outer teeth and the inner teeth meshing, and in which an intake-side volume chamber for taking in a liquid and an ejection-side volume chamber for ejecting liquid taken into the intake-side volume chamber are formed between the inner teeth and the outer teeth; a liquid intake nozzle 9 extending in a non-perpendicular direction with respect to the trochoid rotation surfaces and having a distal end immersed in a liquid reservoir 18; a pump casing 5 in which a recessed portion 5a for accommodating the trochoid is formed; and a pump cover 6 for closing off the recessed portion. An intake cover 8 that has the liquid intake nozzle 9 is secured to the pump casing 5, and the liquid intake nozzle 9 and the intake cover 8 are integrally molded by the injection molding of a resin composition.