Fuel Pump Inner Gear Tilt Surface Friction Reduction
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Solution Overview
Problem
Existing fuel pumps face limitations in material choice due to high abrasion resistance requirements, which restrict the selection of components for the pump housing, especially when the inner gear is rotated and frictional forces are applied.
Innovation Solution
Incorporating a tilt surface in at least one of the receiving hole and the contact portion, which allows the receiving hole to be urged toward the pump housing in both the axial and circumferential directions, reducing the sliding friction and thereby lowering the abrasion resistance needed for the housing components, thus increasing the freedom in material selection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inner gear is rotated using a contact portion and receiving hole extending in the axial direction, then the inner gear can be driven to rotate, but the first and second housing components experience sliding friction requiring high abrasion resistance
Solution Approach 1:
The patent introduces a tilt surface that is tilted relative to the axial direction, changing the contact geometry from purely axial to a combination of axial and radial components. This dimensional change allows the receiving hole to be urged toward the drive rotation side in both circumferential and axial directions, converting sliding friction into a combination of rolling contact and reduced sliding contact, thereby reducing the abrasion resistance requirement for the housing components.
2Device complexity
If the receiving hole and contact portion extend in the axial direction, then the structure is simple, but the housing components require high abrasion resistance to prevent sliding
Solution Approach 1:
The patent applies the tilt surface only at the critical contact region between the receiving hole and contact portion, rather than changing the entire geometry. This localized modification maintains the overall simplicity of the axial extension structure while introducing the necessary radial component to reduce friction at the specific contact interface, achieving a balance between structural simplicity and friction reduction.
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
This design allows for a wider range of material choices for the fuel pump components, enhancing durability and reducing the required abrasion resistance, while maintaining efficient fuel drawing and discharge operations.
Implementation Method 1
the first housing component and the second housing component may be slid when the first housing component and the second housing component receive a frictional force that is equal to or larger than a certain level
Data Source
AI summary
A fuel pump includes: an outer gear; an inner gear that is meshed with the outer gear and includes a receiving hole; a rotatable shaft; a contact portion that is formed to be contactable with the receiving hole; and a pump housing that rotatably receives the outer gear and the inner gear and includes a first housing component and a second housing component, between which the inner gear is held in the axial direction. At least one of the receiving hole and the contact portion includes a tilt surface, which is tilted relative to the axis direction. When the rotatable shaft is rotated to a drive rotation side, the receiving hole contacts the contact portion through the tilt surface, so that the receiving hole is urged in a circumferential direction and is also urged toward the first housing component in the axial direction.