Single Vane Pump Cardioid Chamber High Speed Wear
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Solution Overview
Problem
Single-vane vacuum pumps are not suitable for high rotation speeds due to high wear at the vane ends, which limits their reliability and prevents them from being driven by a counter-rotating balance shaft, reducing their effectiveness in applications requiring high engine revolution multiplication.
Innovation Solution
The design incorporates a cardioid-shaped perimetric surface and a dual-rotor configuration where the vane remains tangent, reducing wear and allowing operation at high speeds, with one rotor driving the other to achieve double displacement and lower dynamic loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the rotor is made to rotate at high rotation speeds, then the productivity of the vacuum pump is improved, but the wearing at the opposite free ends of the vane increases significantly
Solution Approach 1:
The invention replaces the conventional circular chamber with a cardioid-shaped chamber. This curved geometry transforms the vane's motion from sliding contact to tangent contact along the curved perimetric surface. The cardioid shape ensures that the vane ends remain tangent to the surface during rotation, eliminating the high-wear sliding motion that occurs in circular chambers and enabling high-speed operation without excessive wear.
2Device complexity
If the rotor is dragged directly by the engine drive shaft, then the device complexity is reduced, but the reliability becomes critical at high rotation speeds due to vane wear
Solution Approach 1:
The cardioid-shaped chamber geometry fundamentally changes the kinematics of vane motion. Instead of sliding against the chamber wall during rotation, the vane ends maintain tangent contact with the curved perimetric surface throughout the rotation cycle. This geometric solution eliminates the need for complex wear-mitigation mechanisms while maintaining reliability at high rotation speeds achieved through direct engine drive shaft connection.
3Productivity
If the rotor rotates at high speeds to increase productivity, then the vacuum pump output is improved, but the wearing at the vane ends prevents operation at such speeds
Solution Approach 1:
The cardioid chamber geometry transforms the harmful sliding contact into beneficial tangent contact. The curved perimetric surface guides the vane ends through the rotation cycle, ensuring they remain tangent to the surface rather than sliding against it. This geometric innovation eliminates the wearing problem that would otherwise prevent high-speed operation and high productivity.
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 significantly reduces vane wear, enables operation at high speeds, and increases specific displacement by about 50% compared to prior art, making the pump suitable for both high and low revolution applications with reduced overall dimensions.
Implementation Method 1
the opposite free ends of the vane always remain tangent to the perimetric surface of the chamber without slithering on said surface
Implementation Method 2
The rotor is mounted eccentrically in the chamber and it is tangent at one point to the perimetric surface of the chamber
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a single-vane pump comprising a stator (11), a first rotor (13) mounted in the chamber (20) of the stator and capable of rotating around an axis (M-M) and a vane (12) slidably mounted in a diametric groove (30) of the rotor (13) and having a rectilinear portion (26) having a predetermined length (L) and opposite free ends (22, 24) in contact with a perimetric surface (lib) of the chamber (20). A second rotor (14) is mounted in the chamber (20) and is capable of rotating around an axis (0-0) which is parallel to the axis (M-M). The vane (12) is pivoted to the rotor (14), at a longitudinal middle area thereof, on an axis (P-P) parallel to the axis (M-M). The distance between the axis (M-M) and the axis (0-0) and between the axis (P-P) and the axis (0-0) is equal to a fourth of the length (L) of the rectilinear portion (26) of the vane (12). The perimetric surface (lib) of the chamber (20) has, in a plane perpendicular to the axis (M-M), a cardioid shape that coincides with the cardioid defined by the ends (22, 24) of the vane (12) during the rotation of the rotors (13, 14).