Variable cam phaser apparatus

Abstract

A cam phaser apparatus comprising a triple member gear system for transferring a driving torque from a drive member to a driven member and for selectively adjusting the angular relationship between the drive and driven members, said triple member gear system comprising a first member comprising a driving part, a second member comprising a driven part connectable to a cam sprocket or pulley, and a third member comprising an adjusting means connectable to a camshaft, said third member being connected to means for rotating said third member or applying a braking torque and/or a motoring torque to said third member to vary the angular relationship between the first and second members, wherein the cam phaser apparatus further comprises a selectively actuable coupling means for selectively coupling two of said first, second and third members. In one embodiment the coupling means comprises a magnetic coupling.

Description

BRIEF DESCRIPTION OF DRAWINGS

Embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of a planetary gear system known for use in a cam phaser;

FIG. 2 is a perspective view of a harmonic drive system known for use in a cam phaser;

FIG. 3 is a schematic view of a cam phaser apparatus according to an embodiment of the present invention;

FIG. 4 is an exploded view of a magnetic coupling of a cam phaser apparatus according to a first embodiment of the present invention and;

FIG. 5 is a perspective view of a magnetic coupling according to a second embodiment of the present invention.

Claims

1. A cam phaser apparatus comprising a triple member gear system, such as a planetary gear system, harmonic drive or magnetic gear, for transferring a driving torque from a drive member to a driven member and for selectively adjusting the angular relationship between the drive and driven members, said triple member gear system comprising a first member comprising a driving part of said triple member gear system, a second member comprising a driven part of said triple member gear system connectable to a cam sprocket or pulley, and a third member comprising an adjusting means of said triple member gear system connectable to a camshaft, said third member being connected to means for rotating said third member or applying a braking torque and/or a motoring torque to said third member to vary the angular relationship between the first and second members, wherein the cam phaser apparatus further comprises a selectively actuable coupling means for selectively coupling two of said first, second and third members.

2. A cam phaser apparatus as claimed in claim 1, wherein said coupling means comprises an electromagnetic coupling.

3. A cam phaser apparatus as claimed in claim 1, wherein the coupling means comprises first and second rotatably mounted coaxial members, a first member connected to one of said three members of the triple member gear system, a second member connected to another of said three members of the triple member gear system, said first and second members being spaced apart from one another, one of said first and second members comprising at least one magnetically conductive region and the other of said first and second members incorporating means for selectively generating a magnetic flux to constrain the first and second members to rotate together.

4. A cam phaser apparatus as claimed in claim 2, wherein the coupling means comprises first and second rotatably mounted coaxial members, a first member connected to one of said three members of the triple member gear system, a second member connected to another of said three members of the triple member gear system, said first and second members being spaced apart from one another, one of said first and second members comprising at least one magnetically conductive region and the other of said first and second members incorporating means for selectively generating a magnetic flux to constrain the first and second members to rotate together.

5. A cam phaser apparatus as claimed in claim 3, wherein said means for selectively generating a magnetic flux comprises a solenoid.

6. A cam phaser apparatus as claimed in claim 4, wherein said means for selectively generating a magnetic flux comprises a solenoid.

7. A cam phaser apparatus as claimed in claim 5, wherein said first and second members of said coupling means respectively comprise concentrically arranged inner and outer rotors having a radial gap therebetween.

8. A cam phaser apparatus as claimed in claim 6, wherein said first and second members of said coupling means respectively comprise concentrically arranged inner and outer rotors having a radial gap therebetween.

9. A cam phaser apparatus as claimed in claim 5, wherein said first and second members of said coupling means comprise axially spaced members having respective axially spaced opposing face portions.

10. A cam phaser apparatus as claimed in claim 6, wherein said first and second members of said coupling means comprise axially spaced members having respective axially spaced opposing face portions.

11. A cam phaser apparatus as claimed in claim 1, wherein said coupling means comprises a selectively actuable mechanical coupling.