Screw-Spindle Pump Angled Abutments Leakage
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Solution Overview
Problem
Screw-spindle pumps in fuel delivery assemblies of vehicles experience inefficiencies due to oblique positioning or crossing of screw spindles, leading to increased inner leakage and torque requirements, which are not effectively addressed by existing support mechanisms.
Innovation Solution
The pump housing features angled abutments for the screw spindles, set relative to specific planes, to counteract oblique positioning, reducing inner leakage and improving efficiency, with inserts providing support and potentially being made from ceramic or metal for enhanced friction reduction and wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If planar abutment surfaces are used to support screw spindles, then axial displacement is intercepted, but oblique positioning or crossing of screws remains uninfluenced leading to increased inner leakage
Solution Approach 1:
The abutment surfaces are changed from planar to angled relative to the pump axis, modifying the geometric parameter to counteract the oblique positioning of screws during operation, thereby reducing inner leakage while maintaining support functionality
Solution Approach 2:
The abutment surfaces are positioned asymmetrically at specific angles rather than symmetrically in planar configuration, allowing differential support that compensates for the oblique crossing tendency of the screw spindles during rotation
2Productivity
If angled abutments are used to counteract oblique positioning, then inner leakage is reduced, but device complexity increases due to angled support structures
Solution Approach 1:
The angled abutments serve multiple functions simultaneously: they provide axial support for the screw spindles and counteract oblique positioning, eliminating the need for separate correction mechanisms and reducing overall device complexity despite the angled geometry
3Reliability
If ceramic or metal inserts are used for abutments, then friction and wear are reduced, but manufacturing complexity and cost increase
Solution Approach 1:
Ceramic or metal inserts are used as abutment elements combining the hardness and wear resistance of ceramic/metals with the structural integration capability of injection-molded plastic housings, creating a composite structure that balances durability with manufacturability
Data Source
AI summary
A screw-spindle pump includes: a first (drive) screw spindle and a second (running) screw spindle that runs oppositely with respect to the first screw spindle; and a pump housing configured to receive the first and second screw spindles. The first and second screw spindles form, together with at least the pump housing, delivery chambers, which move from a suction side of the pump to a pressure side of the pump due to a rotation of the first and second screw spindles. The pump housing has a first abutment insert for the first screw spindle and a second abutment insert for the second screw spindle, and at least one of the first and second abutment inserts is set angled with respect to a first plane of the pump, to counteract operationally induced crossing of the first and second screw spindles.