Fuel Pump Impeller Housing Clearance Control
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Solution Overview
Problem
The existing fuel pump design faces challenges in increasing the outer diameter of the impeller without enlarging the fuel pump's outer diameter, leading to convex deformation of the casing, which disrupts the clearance between the impeller and the casing, affecting fuel discharge performance.
Innovation Solution
The fuel pump design includes a housing with internally-large and internally-small cylindrical portions, a press-inserted casing portion, and an accommodating disc portion, where specific distances between the press-inserted corner and the impeller-side surface are maintained to regulate convex and concave deformations, ensuring a predetermined clearance and optimal fuel discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the outer diameter of the impeller is increased to increase flow rate, then the flow rate is improved, but the outer diameter of the fuel pump must be increased
Solution Approach 1:
The patent changes the spatial arrangement by moving the impeller off-center within the casing, creating an asymmetric configuration. This dimensional repositioning allows the impeller to have a larger effective outer diameter for increased flow rate while the overall fuel pump outer diameter remains constrained by the housing dimensions. The impeller is positioned closer to one end of the casing, utilizing three-dimensional space more efficiently.
2Length of moving object
If the accommodating cylindrical portion of the casing is reduced in thickness to accommodate larger impeller, then the impeller outer diameter can be increased, but the accommodating disc portion may be convexly deformed
Solution Approach 1:
The patent applies preliminary reinforcement to the accommodating disc portion by increasing its thickness in specific regions before assembly. The disc portion is designed with variable thickness, being thicker near the press-inserted portion to prevent convex deformation during the press-fit process. This preemptive structural strengthening counteracts the potential deformation caused by the press-insertion of the casing into the housing.
Solution Approach 2:
The accommodating disc portion is designed with non-uniform thickness distribution, being locally thicker in regions subjected to higher stress during press-insertion. This local quality enhancement provides targeted reinforcement where needed while maintaining overall design efficiency, preventing deformation without unnecessarily increasing the thickness throughout the entire disc portion.
3Length of moving object
If the accommodating disc portion is convexly deformed, then the impeller outer diameter can be increased, but the clearance between casing and impeller cannot be maintained
Solution Approach 1:
The patent implements preliminary anti-action by pre-reinforcing the accommodating disc portion with increased thickness in critical areas before assembly. This structural reinforcement prevents convex deformation during press-insertion, ensuring that the clearance between the casing and impeller is maintained at the designed value. The disc portion is designed to resist deformation forces, preserving the precise clearance necessary for proper impeller-casing interaction.
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 the enlargement of the impeller's outer diameter while maintaining a reduced fuel pump outer diameter, regulating deformations to prevent fuel leakage and ensure efficient fuel discharge, thereby enhancing the pump's performance and preventing defective assembly recognition.
Implementation Method 1
The press-inserted portion is press-inserted to the inner circumferential periphery of the small inner-diameter cylindrical portion
Data Source
AI summary
A fuel pump includes a housing including an internally-large cylindrical portion coaxial with an internally-small cylindrical portion. A press-inserted portion is press-inserted to the internally-small cylindrical portion. An accommodating cylindrical portion is located in the internally-large cylindrical portion. An accommodating disc portion is opposed to the impeller. A cover is in contact with the accommodating cylindrical portion on the opposite side of the accommodating disc portion. The accommodating disc portion has an impeller-side surface abutted to the accommodating cylindrical portion via an accommodating corner. The outer circumferential periphery of the press-inserted portion has an axial end defining a press-inserted corner on the side of the accommodating cylindrical portion. The accommodating corner is distant from the press-inserted corner for a first distance. The outer circumferential periphery of the press-inserted portion has an axially center portion being distant from the impeller-side surface for a second distance.