Vane Pump Radial Connection Hole for Grinding Accuracy
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Solution Overview
Problem
Conventional vane pumps used in fuel vapor leakage detection devices face challenges in achieving high intake and exhaust efficiency due to complexities in manufacturing and accuracy issues during grinding processes, which affect the airtightness and pipe friction, leading to reduced vapor intake efficiency.
Innovation Solution
The vane pump design incorporates a housing with a tubular portion, first and second plate portions, and a first connection hole forming portion that allows for accurate grinding of end surfaces without interference, reducing pipe friction and enhancing fluid flow efficiency by optimizing the dimensions and orientation of the connection holes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the connection passage forming portion is made large in size, then it is easier to form the connection passage, but the grinding accuracy of the cam ring end surfaces deteriorates
Solution Approach 1:
The housing is divided into a cam ring and a connection passage forming portion as separate structural elements. The connection passage forming portion is positioned radially outside the cam ring, allowing the end surfaces of the cam ring to be ground independently without interference from the connection passage forming portion, thus maintaining high grinding accuracy while still enabling easy formation of the connection passage.
2Manufacturing precision
If the connection passage forming portion is made small in size, then the grinding accuracy of cam ring end surfaces is improved, but the cross-sectional area of the connection passage is reduced
Solution Approach 1:
The connection passage is designed to extend primarily in the radial direction rather than the axial direction. The first connection hole communicates the pump chamber with the outside by extending radially outward from the cam ring, perpendicular to the axial direction in which the cam ring end surfaces are ground. This dimensional orientation allows the connection passage to maintain a sufficient cross-sectional area for vapor flow while not interfering with the axial grinding process of the cam ring end surfaces.
3Productivity
If the connection passage cross-sectional area is increased, then vapor flow efficiency is improved, but pipe friction is increased
Solution Approach 1:
The connection passage is oriented radially rather than axially, changing the flow direction to be perpendicular to the cam ring end surfaces. This radial orientation allows the vapor to flow through a passage with sufficient cross-sectional area to minimize friction losses, while the passage geometry can be optimized to maintain smooth flow characteristics and reduce turbulence, thereby improving vapor intake efficiency without excessive pipe friction.
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 configuration enables high-accuracy grinding of the cam ring end surfaces, maintains airtightness, and reduces pipe friction, thereby enhancing the intake and exhaust efficiency of the vane pump.
Implementation Method 1
The rotor is rotational in the pump chamber. The rotor includes a plurality of vanes configured to slide on an inner wall of the housing.
Implementation Method 2
The motor rotates the rotor.
Data Source
AI summary
A first plate portion covers one opening of a pump chamber of a tubular portion, and a second plate portion covers the other opening of the pump chamber along a center axis of the tubular portion. A hole forming portion is equipped to an outside of the tubular portion to form a connection hole. A length of the hole forming portion along the center axis is less than or equal to a length of the tubular portion along the center axis. A first imaginary line connects a center of an outer opening of the connection hole with a point on the center axis. The first imaginary line intersects perpendicularly with the center axis. A length of the connection hole in a direction perpendicular to both the first imaginary line and the center axis is greater than a length of the connection hole along the center axis.