Multi-positional camshaft phaser with switchable one-way wedge clutches

Abstract

A camshaft phaser including a rotatable stator arranged to receive torque from an engine, a hub arranged to non-rotatably connect to a camshaft and including first and second pluralities of circumferentially disposed ramps, a first wedge plate including: a first aperture and a third plurality of circumferentially disposed ramps engaged with the first plurality of circumferentially disposed ramps, a second wedge plate including: a second aperture and a fourth plurality of circumferentially disposed ramps engaged with the second plurality of circumferentially disposed ramps, and an engagement assembly including a shaft extending axially through the first and second apertures. For an advance or retard mode, the shaft is arranged to be displaced axially so that the hub is rotatable with respect to the stator in a first or second circumferential direction.

What is claimed is: 
     
         1 . A camshaft phaser, comprising:
 a rotatable stator arranged to receive torque from an engine;   a hub arranged to non-rotatably connect to a camshaft and including first and second pluralities of circumferentially disposed ramps;   a first wedge plate including:
 a first aperture; and, 
 a third plurality of circumferentially disposed ramps engaged with the first plurality of circumferentially disposed ramps; 
   a second wedge plate including:
 a second aperture; and, 
 a fourth plurality of circumferentially disposed ramps engaged with the second plurality of circumferentially disposed ramps; and, 
   an engagement assembly including a shaft extending axially through the first and second apertures, wherein:
 for an advance mode, the shaft is arranged to be displaced in a first axial direction so that the hub is rotatable with respect to the stator in a first circumferential direction; and, 
 for a retard mode, the shaft is arranged to be displaced in a second axial direction, opposite the first axial direction, so that the hub is rotatable with respect to the stator in a second circumferential direction, opposite the first circumferential direction. 
   
     
     
         2 . The camshaft phaser of  claim 1 , wherein:
 for the advance mode, rotation of the hub, with respect to the rotatable stator, in the second circumferential direction is blocked; and,   for the retard mode, rotation of the hub, with respect to the rotatable stator, in the first circumferential direction is blocked.   
     
     
         3 . The camshaft phaser of  claim 1 , wherein:
 for the advance mode:
 the first wedge plate is non-rotatably connected to the shaft; and, 
 the second wedge plate is rotatable with respect to the shaft; and, 
   for the retard mode:
 the second wedge plate is non-rotatably connected to the shaft; and, 
 the first wedge plate is rotatable with respect to the shaft. 
   
     
     
         4 . The camshaft phaser of  claim 1 , wherein the shaft includes:
 a first portion having a first outer diameter;   a second portion having a second outer diameter; and,   a third portion having a third outer diameter greater than the first and second outer diameters, the third portion disposed:
 in the first aperture in the advance mode; and, 
 in the second aperture in the retard mode. 
   
     
     
         5 . The camshaft phaser of  claim 4 , wherein for a drive mode:
 the first portion is disposed in the first aperture;   the second portion is disposed in the second aperture; and,   the first and second apertures are arranged to rotate with respect to the shaft to enable relative rotation between the first and second wedge plates, respectively, and the hub.   
     
     
         6 . The camshaft phaser of  claim 5 , wherein:
 to shift from the drive mode to the advance mode:
 the shaft is arranged to block rotation of the first wedge plate with respect to the hub; and, 
 the second aperture is arranged to rotate with respect to the shaft to enable relative rotation between the second wedge plate and the hub; and, 
   to shift from the drive mode to the retard mode:
 the shaft is arranged to block rotation of the second wedge plate with respect to the hub; and, 
 the first aperture is arranged to rotate with respect to the shaft to enable relative rotation between the first wedge plate and the hub. 
   
     
     
         7 . The camshaft phaser of  claim 5 , wherein:
 to shift from the drive mode to the advance mode, the second aperture is arranged to rotate, with respect to the shaft, in the second circumferential direction; and,   to shift from the drive mode to the retard mode, the first aperture is arranged to rotate, with respect to the shaft, in the first circumferential direction.   
     
     
         8 . The camshaft phaser of  claim 1 , wherein the engagement assembly includes:
 a first plate directly connected to a first axial end of the shaft; and,   a second plate directly connected to a second axial end, opposite the first axial end, of the shaft.   
     
     
         9 . The camshaft phaser of  claim 8 , wherein the engagement assembly includes:
 a first actuator arranged to displace the first plate in the first axial direction; and,   a second actuator arranged to displace the second plate in the second axial direction.   
     
     
         10 . The camshaft phaser of  claim 1 , wherein:
 the rotatable stator includes a radially inner surface with first and second circumferentially extending grooves; and,   radially outermost portions of the first and second wedge plates are:
 disposed in the first and second grooves, respectively, and; 
 frictionally engaged with the first and second grooves, respectively. 
   
     
     
         11 . A camshaft phaser, comprising:
 a rotatable stator arranged to receive torque from an engine;   a hub arranged to non-rotatably connect to a camshaft and including first and second pluralities of circumferentially disposed ramps;   a first wedge plate including:
 a first plurality of apertures; and, 
 a third plurality of circumferentially disposed ramps engaged with the first plurality of circumferentially disposed ramps; 
   a second wedge plate including:
 a second plurality of apertures; and, 
 a fourth plurality of circumferentially disposed ramps engaged with the second plurality of circumferentially disposed ramps; and, 
   an engagement assembly including a plurality of shafts extending axially through the first and second pluralities of apertures, wherein:
 for a drive mode, the first and second wedge plates are arranged to be rotatable with respect to the plurality of shafts so that the first and second wedge plates rotate with respect to the hub and non-rotatably connect to the rotatable stator and the hub; 
 to initiate an advance mode, the second wedge plate is arranged to be rotatable with respect to the plurality of shafts so that the second wedge plate rotates with respect to the hub and non-rotatably connects to the rotatable stator and the hub; and, 
 to initiate a retard mode, the first wedge plate is arranged to be rotatable with respect to the plurality of shafts so that the first wedge plate rotates with respect to the hub and non-rotatably connects to the rotatable stator and the hub. 
   
     
     
         12 . The camshaft phaser of  claim 11 , wherein:
 in the advance mode, the second wedge plate is non-rotatably connected to the hub in a first circumferential direction; and,   in the retard mode, the first wedge plate is non-rotatably connected to the hub in a second circumferential direction, opposite the first circumferential direction.   
     
     
         13 . The camshaft phaser of  claim 11 , wherein:
 in the advance mode, the second plurality of apertures are arranged to rotate with respect to the plurality of shafts to enable relative rotation between the second wedge plate and the hub; and,   in the retard mode, the first plurality of apertures are arranged to rotate with respect to the plurality of shafts to enable relative rotation between the first wedge plate and the hub.   
     
     
         14 . The camshaft phaser of  claim 11 , wherein each shaft of the plurality of shafts includes:
 a first portion having a first outer diameter;   a second portion having a second outer diameter; and,   a third portion having a third outer diameter greater than the first and second outer diameters.   
     
     
         15 . The camshaft phaser of  claim 14 , wherein:
 in the drive mode, the first and second portions are disposed in the first and second pluralities of apertures, respectively;   in the advance mode:
 the first portion of said each shaft is disposed in the first plurality of apertures; and, 
 the third portion of each shaft is disposed in the second plurality of apertures; and, 
   in the retard mode:
 the second portion of said each shaft is disposed in the second plurality of apertures; and, 
 the third portion of each shaft is disposed in the first plurality of apertures. 
   
     
     
         16 . The camshaft phaser of  claim 11 , wherein:
 in the advance mode, the plurality of shafts is arranged to block rotation of the first wedge plate with respect to the hub; and,   in the retard mode, the plurality of shafts is arranged to block rotation of the second wedge plate with respect to the hub.   
     
     
         17 . The camshaft phaser of  claim 11 , wherein the engagement assembly includes:
 a first plate directly connected to respective first axial ends of the plurality of shafts; and,   a second plate directly connected to respective second axial ends, opposite the respective first axial ends, of the plurality of shafts.   
     
     
         18 . The camshaft phaser of  claim 17 , wherein the engagement assembly includes:
 a first actuator arranged to displace the first plate in the first axial direction; and,   a second actuator arranged to displace the second plate in the second axial direction.   
     
     
         19 . The camshaft phaser of  claim 11 , wherein the rotatable stator includes at least one radially inwardly extending protrusion disposed circumferentially between adjacent shafts to limit relative rotation between the hub and the rotatable stator. 
     
     
         20 . A method of phasing a camshaft, comprising the steps of:
 receiving, using a rotatable stator non-rotatably connected to a housing, torque from an engine;   for an advance mode, displacing a shaft for an engagement assembly, the shaft extending axially through first and second apertures in first and second wedge plates, respectively, in a first axial direction so that:
 a first plurality of circumferentially disposed ramps for a hub, arranged to non-rotatably connect to a camshaft, engage a second plurality of circumferentially disposed ramps for the first wedge plate to block rotation of the hub, with respect to the stator in a first circumferential direction; and, 
 the hub is rotatable with respect to the stator in a second circumferential direction, opposite the first circumferential direction; 
   for a retard mode, displacing the shaft for the engagement assembly in a second axial direction, opposite the first axial direction so that:
 a third plurality of circumferentially disposed ramps for the hub engage a fourth plurality of circumferentially disposed ramps for the second wedge plate to block rotation of the hub, with respect to the stator in the second circumferential direction; and, 
 the hub is rotatable with respect to the stator in the first circumferential direction; and, 
   for a drive mode, displacing the shaft for the engagement assembly in the first or second axial direction to block rotation of the hub, with respect to the stator in the first and second circumferential directions.