Variable phase mechanism

Abstract

A yoke-type phaser is disclosed having a drive member and a driven member rotatable about a common axis and coupled to one another by means of a yoke that is movable, in a plane normal to the common axis, to vary the relative phase of the drive and driven members, by interaction between at least two contact elements and a contoured surface, one of (i) the contact elements and (ii) the contoured surface being connected for rotation with the drive member and the other being mounted on the yoke, each contact element comprising a roller in surface contact with a part-cylindrical recess in a carrier, wherein the carrier of at least one of the contact elements is either appropriately sized or adjustably mounted, to set the clearances between the rollers and the contoured surface.

1 . A yoke-type phaser having a drive member and a driven member rotatable about a common axis and coupled to one another by means of a yoke that is movable, in a plane normal to the common axis, to vary the relative phase of the driven member relative to the drive member, by interaction between at least two contact elements and a contoured surface, one of the contact elements and the contoured surface being connected for rotation with the drive member and the other being mounted on the yoke, each contact element comprising a roller in surface contact with a part-cylindrical recess in a carrier;
 wherein the carrier of at least one of the contact elements is either appropriately sized, or adjustably mounted, to set the clearances between the rollers and the contoured surface.   
     
     
         2 . A dual phaser for connecting a drive member to first and second driven members, all three members being rotatable about a common axis, wherein the drive member is connected to the first driven member by means of a first phaser and to the second driven member by means of a yoke-type phaser that comprises a yoke movable, in a plane normal to the common axis, to vary the phase of the second driven member relative to the drive member by interaction between at least two contact elements and a contoured surface, one of the contact elements and the contoured surface being defined by or mounted on the first driven member and the other being defined by or mounted on the yoke, each contact element comprising a roller in surface contact with a part-cylindrical recess in a carrier;
 wherein the carrier of at least one of the contact elements is either appropriately sized, or adjustably mounted, to set the clearances between the rollers and the contoured surface.   
     
     
         3 . The dual phaser as claimed in  claim 2 , wherein the position of the carrier of at least one of the contact elements is adjustable by means of shims. 
     
     
         4 . The phaser as claimed in  claim 2 , wherein the carrier of at least one of the contact elements is retained in position by means of a screw passing through an elongate slot in the carrier. 
     
     
         5 . The dual phaser as claimed in  claim 2 , wherein the position of the carrier of at least one of the contact elements is adjustable by means of a hydraulic lash adjuster. 
     
     
         6 . The dual phaser as claimed in  claim 2 , wherein each of the two phasers is provided with a respective bias spring to counteract resistive torques of the respective driven members. 
     
     
         7 . The dual phaser as claimed in  claim 2 , wherein the first phaser is a vane-type phaser.