Vane Pump Tappet Peg Oval Recess Design
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Solution Overview
Problem
Existing vane pumps with cylindrical tappet pegs experience high surface pressure, leading to reduced service life of tappet pegs and rotor due to deep material penetration.
Innovation Solution
The vane pump design features an oval-shaped rotor recess and contoured tappet pegs with larger radii in contact areas, reducing surface pressure and preventing deep material penetration, thereby extending the service life of tappet pegs and rotor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If cylindrical tappet pegs with circular cross-section are used, then the structure is simple and easy to manufacture, but the surface pressure is extremely high causing deep material penetration and reduced service life
Solution Approach 1:
The tappet peg is given a contoured shape with curved surfaces instead of a simple cylindrical form. The contour includes a first curved contoured section with a larger radius of curvature in the contact area, which distributes the load over a larger surface area, reducing surface pressure and preventing deep material penetration into the rotor recess.
Solution Approach 2:
The tappet peg features localized contouring specifically in the contact areas where it engages with the rotor recess. The first curved contoured section with enlarged radius is positioned precisely at the contact zone to reduce surface pressure, while other portions of the tappet peg maintain simpler geometry for manufacturing ease.
2Device complexity
If cylindrical tappet pegs are used, then the design is simple, but the surface pressure causes the tappet pegs to advance deep into the material reducing service life
Solution Approach 1:
The tappet peg incorporates a contoured shape with curved surfaces, specifically a first curved contoured section with enlarged radius in the contact area. This curvature distributes contact pressure over a larger area, preventing the tappet peg from advancing deeply into the rotor recess material, thereby extending service life while maintaining reasonable design simplicity.
3Reliability
If the tappet peg has a contoured shape with larger radii in contact areas, then the surface pressure is reduced and service life is extended, but the manufacturing complexity increases
Solution Approach 1:
The contouring is applied locally only to the critical contact areas of the tappet peg where it engages with the rotor recess. The first curved contoured section with enlarged radius is positioned precisely at the contact zone to reduce surface pressure, while other portions of the tappet peg maintain simpler geometry, minimizing the increase in manufacturing complexity.
Data Source
AI summary
A vane pump includes an electric drive unit with an electric motor and a motor shaft, a pump chamber attached on the electric drive unit, and a rotor having a plurality of blades. The rotor is arranged concentrically to the motor shaft within the pump chamber, and the motor shaft is engaged with the rotor by way of a tappet which is connected torsionally rigid with the motor shaft. The tappet has at least one tappet peg, which is engaged in a rotor recess, that corresponds to the tappet peg, wherein the at least one rotor recess has an oval shape, and the tappet peg is contoured in such a way that two first slightly curved contoured sections each form one contact area with one oblong planar section corresponding with one each of the rotor recesses.