Screw Spindle Pump Offset Interface Centering
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Solution Overview
Problem
Existing fuel delivery assemblies with screw-spindle pumps face challenges in achieving a statically determined installation position with respect to the electric motor, leading to potential installation issues, increased space requirements, and noise generation due to indeterminate installation situations.
Innovation Solution
A screw-spindle pump stage with an offset interface and centering action on the pump housing, combined with an axial preload and radial seals, ensures a statically determined installation position, reduces the rolling region size, and minimizes structure-borne noise by using existing sheet-metal casing lengths and modular systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pump is rolled together with the electric motor in a sheet-metal casing, then both components are encapsulated and sealingly enclosed, but the pump installation position becomes indeterminate and statically overdetermined
Solution Approach 1:
The patent extracts the centering function from the general rolling process by introducing a dedicated centering seat in the electric motor and a corresponding centering element on the pump housing. This separates the sealing enclosure function (achieved through rolling) from the position determination function (achieved through the centering mechanism), resolving the contradiction between reliable sealing and precise position determination.
Solution Approach 2:
The centering element acts as an intermediary between the pump housing and the electric motor, mediating the interaction during rolling. It translates the rolling motion into a precisely determined installation position while still allowing the sheet-metal casing to provide sealing enclosure, thus resolving the contradiction between these two requirements.
2Reliability
If axial seals and interfaces are arranged on the pump to enable rolling with the electric motor, then both components can be encapsulated, but the pump requires increased installation space
Solution Approach 1:
The pump housing is designed with a centering element that nests into the centering seat of the electric motor during the rolling process. This nested arrangement allows the pump and motor to be compactly enclosed together in the sheet-metal casing, achieving reliable encapsulation while minimizing the overall installation space requirement.
3Stability of the object's composition
If the pump is statically overdetermined during rolling, then the installation position is constrained, but this leads to indeterminate installation situations and noise generation
Solution Approach 1:
The patent extracts the position determination function from the rolling process itself and places it in a dedicated centering mechanism. This separation allows the rolling process to focus on sealing enclosure while the centering element handles position determination, eliminating the indeterminate installation situations that cause structure-borne noise.
Solution Approach 2:
The patent replaces the mechanically complex interaction during rolling (which caused indeterminate positions and noise) with a simpler centering element that positively determines the installation position. This substitution eliminates the harmful noise generation while maintaining stable installation constraints.
Data Source
AI summary
A screw-spindle pump stage having a drive spindle and a running spindle which runs opposite the drive spindle and a pump housing for receiving the two screw spindles. The pump housing 16 has an offset interface with centering action, for a statically determined coupling to an electric motor. The pump housing has an offset section functioning as an abutment, which is able to be abutted against the electric motor for the application of an axial preload. At least one pressure region of the abutment section, which is close to the interface and, during a rolling, is encapsulated, and at the same time sealingly enclosed, by a sheet-metal casing, forms a rolling region of the pump, the screw spindles, together with the associated pump housing section, at least partially project from the rolling region of the pump on the suction side.