Patent ID: 9670928
Date: 2017-06-06
CPC Classifications: F01C,F04C

Claim:
1. A vacuum pump for a motor vehicle engine, comprising: a stator; a vacuum chamber defined inside said stator, said vacuum chamber having a side wall whose transversal section has a predetermined substantially elliptical shape; a rotor mounted in said vacuum chamber and capable of rotating around a rotation axis parallel to said side wall; a single vane mounted on said rotor and free to slide in a direction at right angles with respect to the rotation axis of said rotor, said single vane comprising a central body having a predetermined length and two opposite end portions that are integrally formed with said central body; wherein relative movements between the central body and the two opposite end portions are prevented, and wherein the single vane is one piece, is smoothly continuous in form and all portions making up the whole of the vane are inseparable; said end portions substantially sliding along the side wall of said vacuum chamber; each of said end portions of said single vane comprising two opposite surfaces, said two opposite surfaces symmetrical with respect to a longitudinal axis of said single vane, each surface of said two opposite surfaces is shaped to have a bend radius substantially equal to that of a part of said side wall, when said single vane is in at least one reference operating position, wherein said part is shaped as a circumferential arc having a predetermined radius and is located on the same side of said surface with respect to said longitudinal axis; wherein said single vane is free to slide in a direction passing through the rotation axis of said rotor, the external circumference of said rotor is tangential to the side wall of the chamber along a tangential line parallel to the rotation axis of the rotor, wherein one of said two opposite surfaces of each end portion has a respective curvature centre that is different from the curvature centre of the other of said two opposite surfaces.