Camshaft Phaser

Abstract

A phasing system for an internal combustion engine having a concentric camshaft includes an annular stator rotatable by the crankshaft and having inner and outer circumferences, and two groups of arcuate cavities. The first group interrupts the inner circumference. A first phaser having an output member as a hub is mounted within the stator in contact with the inner circumference and supported directly on the camshaft tube as a concentric stator bearing. The first phaser has vanes connected to the output member and extending radially into the first group to divide cavities into opposed working chambers. A second phaser comprises first and second end plates at opposite stator sides and fastened to one another to axially seal the cavities therein and, as second output member of the second phaser, connect to vanes extending axially through the second group of cavities to divide the cavities into opposed working chambers.

What is claimed is: 
     
         1 . A phasing system for an internal combustion engine having a concentric camshaft, the phasing system comprising:
 an annular stator, rotatable by the crankshaft of the internal combustion engine, having an inner circumference, an outer circumference, and two groups of arcuate cavities, at least a first group of the cavities interrupting the inner circumference of the stator;   a first phaser having an output member in the form of a hub to be concentrically located relative to the camshaft and mounted within the centre of the stator, the outer circumference of the output member being in contact with the inner circumference of the stator to serve as a bearing for the stator, the first phaser further having a plurality of vanes connected to the output member and extending radially into the first group of cavities to divide the cavities into opposed working chambers; and   a second phaser comprising a first end plate and a second end plate located on opposite sides of the stator and fastened to one another in order to axially seal the cavities in the stator, the end plates serving as the output member of the second phaser and being connected to vanes that extend axially through the second group of cavities to divide the cavities into opposed working chambers.   
     
     
         2 . The phasing system of  claim 1 , wherein the second group of cavities also interrupts the inner circumference of the stator. 
     
     
         3 . The phasing system of  claim 1 , wherein the output member of the first phaser features oil passageways for both groups of cavities. 
     
     
         4 . The phasing system of  claim 1 , wherein the second phaser comprises stiffening elements extending between the end plates that serve as the output member of the second phaser, the stiffening elements extending through arcuate slots formed in the stator. 
     
     
         5 . The phasing system of  claim 1 , further comprising at least one locking pin assembly disposed within the stator, for locking the stator relative to the output member of at least one of the phasers. 
     
     
         6 . The phasing system of  claim 5 , wherein the locking pin assembly comprises a pin, a spring having one end received within a hole in the pin, and a spring seat abutting the opposite end of the spring, and wherein the seat has a plurality of axially extending protrusions about its perimeter, aligned with matching slots in the side wall of the pin. 
     
     
         7 . The phasing system of  claim 5 , wherein the locking pin assembly is disposed axially with respect to the camshaft. 
     
     
         8 . The phasing system of  claim 7 , wherein the locking pin assembly is located within a through hole in the stator. 
     
     
         9 . The phasing system of  claim 5 , comprising locking pin assemblies disposed within the stator, for locking the stator relative to the output member of the two phasers. 
     
     
         10 . The phasing system of  claim 9 , wherein one of the locking pin assemblies is disposed radially with respect to the camshaft. 
     
     
         11 . The phasing system of  claim 10 , wherein the radially disposed locking pin assembly is arranged within a housing. 
     
     
         12 . The phasing system of  claim 10 , wherein the first phaser output member features a through slot on its outer circumference configured to receive the pin of the radially disposed locking pin assembly. 
     
     
         13 . The phasing system of  claim 1 , further comprising a spiral spring for applying a balancing torque to the output member of at least one of the two phasers.