Non-Circular Pump Sealing Member Strain Distribution
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Solution Overview
Problem
In fuel-vapor-leakage check systems with vane pumps, the non-perfect circular shape of the suction portion leads to uneven strain forces on sealing members, causing potential twisting and compromising airtightness and liquid-tightness, which deteriorates suction performance and detection accuracy.
Innovation Solution
An assembling unit with a first tubular portion and a second tubular portion, both having non-perfect circular cross-sectional shapes, and an annular rubber sealing member with an elasticity modulus below a specified value, ensuring uniform strain distribution and preventing twisting, thereby maintaining high airtightness and liquid-tightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the suction portion is formed as a non-perfect circle to reduce pump size, then the pump thickness and cam ring height are reduced, but the sealing member experiences non-uniform strain forces causing twisting and deterioration of airtightness
Solution Approach 1:
The patent applies asymmetry by making the cross-sectional shapes of both the first and second tubular portions non-circular (congruent non-circular shapes), which transforms the sealing member's strain distribution to be uniform despite the non-circular geometry. This resolves the contradiction by allowing compact pump design while preventing sealing member twisting and maintaining airtightness.
Solution Approach 2:
The patent changes the geometric parameters of the tubular portions from circular to congruent non-circular shapes, and selects specific elasticity modulus values for the sealing member material. These parameter changes enable the sealing member to experience uniform strain forces even in non-circular configurations, preventing twisting while maintaining compact pump dimensions and reliable airtightness.
2Adaptability or versatility
If the sealing member is made with high elasticity to accommodate non-circular shapes, then the sealing member can deform to fit the shape, but the non-uniform strain distribution causes twisting during assembly
Solution Approach 1:
The patent uses asymmetry in the cross-sectional shapes of the tubular portions to create a geometric configuration that produces uniform strain forces on the sealing member. This uniform strain distribution prevents twisting during assembly, thereby maintaining the sealing member's orientation stability while still accommodating the non-circular shape requirements.
Solution Approach 2:
The patent specifies particular ranges for the elasticity modulus of the sealing member material and the geometric parameters of the non-circular cross-sections. By optimizing these parameters, the sealing member achieves sufficient adaptability to fit the non-circular shapes while maintaining stable orientation and preventing twisting during assembly.
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
The solution effectively restricts rotation and twisting of the sealing member, enhancing airtightness and liquid-tightness between the tubular portions, thereby improving suction performance and detection accuracy of fuel-vapor leakage.
Implementation Method 1
an annular shaped sealing member made of rubber of which elasticity modulus is less than a specified value
Data Source
AI summary
A first tubular portion has a cross sectional shape which is a non-perfect circle relative to an axis thereof. A second tubular portion is disposed concentrically with the first tubular portion. The second tubular portion has a cross sectional shape relative to its axis, which is a congruent shape of the cross sectional shape of the first tubular portion. A sealing member is disposed between the first tubular portion and the second tubular portion for sealing therebetween. The sealing member has a cross sectional shape of which length parallel to its axis is greater than length which is perpendicular to the axis.