Vacuum pump for a motor vehicle engine

• US 9,670,928 B2
• Filed: 07/03/2007
• Issued: 06/06/2017
• Est. Priority Date: 07/03/2007
• Status: Active Grant

• Current Assignee: O.M.P. Officine Mazzocco Pagnoni S.R.L.
• Original Assignee: O.M.P. Officine Mazzocco Pagnoni S.R.L.
• Inventors: Lo Biundo, Giuseppe, De Rango, Alessandra, Pazzi, Giovanni, Pachetti, Carlo
• Primary Examiner(s): Laurenzi, Mark
• Assistant Examiner(s): AYALA DELGADO, ANTHONY
• Application Number:
  US12/667,319
• Publication Number:
  US 20100196187A1
• Time in Patent Office: 3,626 Days
• Field of Search: 418253, 418254, 418255, 418150, 418211, 418259
• CPC Class Codes: F01C 21/0881 the vanes consisting of two or more parts
• CPC Class Codes: F04C 18/3442 the surfaces of the inner and outer member, forming the inlet and outlet opening
• CPC Class Codes: F04C 2220/10 Vacuum
• CPC Class Codes: F04C 27/001 Radial sealings for working fluid

Abstract

A vacuum pump for a motor vehicle engine which has a stator and a chamber, has a side wall, and the side wall has a transversal section with a predetermined shape. The rotor mounted in the chamber is capable of rotating around a rotation axis parallel to the side wall. The vane mounted on the rotor is free to slide in a direction at right angles with respect to the rotation axis of the rotor, and the vane has a predetermined length and two opposite end portions that substantially slide along the side wall of the chamber. At least one of the end portions of the vane has at least one part that has a bend radius substantially equal to that of a part of the side wall, when the one vane is at a reference operating position.

Claims

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.

2. The vacuum pump according to claim 1, wherein said at least one reference operating position is defined at a configuration of maximum stress of the end portions of said single vane against the side wall of the chamber.

3. The vacuum pump according to claim 1, wherein said two opposite surfaces of each of said end portions of said single vane are radiused, at a longitudinal axis of said single vane, by an arc of circumference.

4. The vacuum pump according to claim 3, wherein the diameter of the ideal circumference that defines said arc of circumference is smaller than the thickness of said single vane.

5. The vacuum pump according to claim 4, wherein the ratio between the diameter of the ideal circumference that defines said arc of circumference and the thickness of said single vane ranges between about ⅕

and about ¼

.

6. 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 comprises two opposite surfaces symmetrical with respect to a longitudinal axis of said single vane and 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;

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 has a respective curvature centre that is different from the curvature centre of the other of said two opposite surfaces;

wherein said two opposite surfaces of each of said end portions of said single vane are radiused, at a longitudinal axis of said single vane, by an arc of circumference, wherein the diameter of the ideal circumference that defines said arc of circumference is smaller than the thickness of said single vane, wherein the ratio between the diameter of the ideal circumference that defines said arc of circumference and the thickness of said single vane ranges between ⅕ and

¼

.

7. 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 comprises two opposite surfaces symmetrical with respect to a longitudinal axis of said single vane and 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;

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 has a respective curvature centre that is different from the curvature centre of the other of said two opposite surfaces;

wherein said at least one reference operating position is defined at a configuration of maximum stress of the end portions of said single vane against the side wall of the chamber, said configuration of maximum stress being defined at zones of the chamber which are around the position wherein the longitudinal axis of the vane is at right angles with respect to the plane formed by the rotor rotation axis and a tangential line of the external circumference of the rotor with the side wall of the chamber, said tangential line being parallel to the rotor rotation axis.