Axial and radial source feeds at a rotor to camshaft interface

Abstract

A variable cam timing phaser has a rotor assembly with a central hub defining an axial bore and an interface groove with a first seal land, a second seal land and a single undercut area. A width of the first seal land is greater than a width of the second seal land. The single undercut area is in fluid communication with an axial undercut passage connected to a radial undercut passage within the rotor assembly. A clamping interface is between the camshaft and the rotor assembly, such that a seal is present between first seal land and the first end of the camshaft, and the second seal land and the first end of the camshaft. Fluid from a supply, flows into the passage of the camshaft to the single undercut area, through the axial undercut passage, the radial undercut passage to a passage within the rotor assembly.

What is claimed is: 
     
         1 . A variable camshaft timing phaser comprising:
 a housing assembly having an outer circumference for accepting drive force;   a rotor assembly coaxially located within the housing assembly with a first face and a second face, with at least one chamber defined by the housing assembly and rotor assembly, the rotor assembly comprising:
 a central hub defining an axial bore and an interface groove with a first seal land, a second seal land and a single undercut area, wherein the second seal land is between the single undercut area and a circumferential edge of the central hub, and the first seal land is between a circumferential edge of the central hub and the axial bore other than the single undercut area, such that a width of the first seal land is greater than a width of the second seal land; 
 a rotor body surrounding the central hub having a plurality of vanes extending axially therefrom; wherein the single undercut area is in fluid communication with at least one undercut supply passage within the rotor body having an axial component, a radial component or an axial and a radial component relative to the axial bore; 
   a camshaft connected to the rotor assembly, the camshaft having a first end, a second end, and defining a through passage;   a clamping interface between the first end of the camshaft and the first face of the rotor assembly such that a seal is present between first seal land and the first end of the camshaft, and the second seal land and the first end of the camshaft;   wherein fluid from at least a first supply flows into the passage of the camshaft to the single undercut area, through the at least one undercut supply passage to a passage within the rotor assembly in fluid communication with the at least one chamber at the clamping interface between the camshaft and the rotor assembly to a passage within the rotor assembly in fluid communication with the at least one chamber.   
     
     
         2 . The variable cam timing phaser of  claim 1 , further comprising a center bolt located within the axial bore of the central hub of the rotor assembly extending from bore of the second end plate, through the rotor assembly via the axial bore and through the bore of the first end plate into the passage of the camshaft, the center bolt further comprises a shank body connected to a head at a first end and a shaft at a second end with a plurality of threads, wherein the shank body and the head have a bore extending therethrough, such that the shank body is located within the rotor assembly and the shaft extends into the passage of the camshaft. 
     
     
         3 . The variable cam timing phaser of  claim 2 , further comprising a third sealing land between the axial bore of the central hub of the rotor assembly and the shank body of the center bolt. 
     
     
         4 . The variable cam timing phaser of  claim 2 , wherein a clamping force of the clamping interface is generated through rotation of the center bolt within the rotor assembly and the camshaft, such that threads of the shank body engage with the camshaft. 
     
     
         5 . The variable cam timing phaser of  claim 1 , wherein a clamping force of the clamping interface is generated by welding of the first end of the camshaft to the first face of the rotor assembly. 
     
     
         6 . The variable cam timing phaser of  claim 1 , wherein a minimum clamping distance is present between the first face of the rotor assembly and the first end of the camshaft. 
     
     
         7 . The variable cam timing phaser of  claim 5 , wherein the minimum clamping distance is 1.0 mm. 
     
     
         8 . The variable cam timing phaser of  claim 2 , further comprising a spool valve received within the center bolt. 
     
     
         9 . The variable cam timing phaser of  claim 8 , the spool valve further comprising:
 at least two lands separated by a central spindle, slidably mounted within a sleeve received by a bore of the center bolt, and a plurality of check valves; and a passage from the advance chamber to a port in the spool valve and a passage from the retard chamber to a port in the spool valve, such that when the spool is in the first position, fluid from the advance chamber flows through the passage and the port to the bore surrounding the central spindle of the spool valve and through a first check valve within the spool valve and port to the passage to the retard chamber and when the spool is in the second position, fluid from the retard chamber flows through the passage and the port to the bore surrounding the central spindle of the spool valve and through a second check valve within the spool valve and port to the passage to the advance chamber.   
     
     
         10 . The variable cam timing phaser of  claim 9 , wherein the plurality of check valves are located within the at least two lands of the spool. 
     
     
         11 . The variable cam timing phaser of  claim 1 , further comprising an inlet check valve in the passage within the rotor assembly. 
     
     
         12 . The variable cam timing phaser of  claim 1 , wherein the at least one undercut supply passage comprises a first undercut supply passage and a second undercut supply passage. 
     
     
         13 . A variable camshaft timing phaser comprising:
 a housing assembly having an outer circumference for accepting drive force;   a rotor assembly coaxially located within the housing assembly with a first face and a second face, with at least one chamber defined by the housing assembly and rotor assembly, the rotor assembly comprising:
 a central hub defining an axial bore and an interface groove with a first seal land, a second seal land and a single undercut area, wherein the second seal land is between the single undercut area and a circumferential edge of the central hub, and the first seal land is between a circumferential edge of the central hub and the axial bore other than the single undercut area; 
 a rotor body surrounding the central hub having a plurality of vanes extending axially therefrom; wherein the single undercut area is in fluid communication with at least one undercut supply passage within the rotor body having an axial component, a radial component or an axial and a radial component relative to the axial bore; 
   a camshaft connected to the rotor assembly, the camshaft having a first end, a second end, and defining a through passage;   a clamping interface between the first end of the camshaft and the first face of the rotor assembly such that a seal is present between first seal land and the first end of the camshaft, and the second seal land and the first end of the camshaft;   wherein fluid from at least a first supply flows into the passage of the camshaft to the single undercut area, through the at least one undercut supply passage at the clamping interface between the camshaft and the rotor assembly to a passage within the rotor assembly in fluid communication with the at least one chamber.   
     
     
         14 . The variable cam timing phaser of  claim 13 , further comprising a center bolt located within the axial bore of the central hub of the rotor assembly extending from bore of the second end plate, through the rotor assembly via the axial bore and through the bore of the first end plate into the passage of the camshaft, the center bolt further comprises a shank body connected to a head at a first end and a shaft at a second end with a plurality of threads, wherein the shank body and the head have a bore extending therethrough, such that the shank body is located within the rotor assembly and the shaft extends into the passage of the camshaft. 
     
     
         15 . The variable cam timing phaser of  claim 14 , further comprising a third sealing land between the axial bore of the central hub of the rotor assembly and the shank body of the center bolt. 
     
     
         16 . The variable cam timing phaser of  claim 14 , wherein a clamping force of the clamping interface is generated through rotation of the center bolt within the rotor assembly and the camshaft, such that threads of the shank body engage with the camshaft. 
     
     
         17 . The variable cam timing phaser of  claim 13 , wherein a clamping force of the clamping interface is generated by welding of the first end of the camshaft to the first face of the rotor assembly. 
     
     
         18 . The variable cam timing phaser of  claim 13 , wherein a minimum clamping distance is present between the first face of the rotor assembly and the first end of the camshaft. 
     
     
         19 . The variable cam timing phaser of  claim 18 , wherein the minimum clamping distance is 1.0 mm. 
     
     
         20 . The variable cam timing phaser of  claim 14 , further comprising a spool valve received within the center bolt.