Camshaft phaser

Abstract

An internal combustion engine includes a crankshaft rotatable about a crankshaft axis and a camshaft rotatable by the crankshaft about a camshaft axis. The internal combustion engine also includes an oil supply, an engine cover, and a drive member disposed within the engine cover for transferring rotational motion from the crankshaft to the camshaft. A camshaft phaser is disposed within the engine cover for controllably varying the phase relationship between the crankshaft and the camshaft by using oil from the oil supply. A sealing arrangement defines a dry zone to isolate the drive member from oil used to rotate the output member relative to the input member.

We claim: 
     
         1 . An internal combustion engine having a crankshaft rotatable about a crankshaft axis and a camshaft rotatable by said crankshaft about a camshaft axis, said internal combustion engine comprising:
 a) an oil supply;   b) an engine cover;   c) a drive member disposed within said engine cover for transferring rotational motion from said crankshaft to said camshaft;   d) a camshaft phaser disposed within said engine cover for controllably varying the phase relationship between said crankshaft and said camshaft, said camshaft phaser comprising:
 i) an input member driven by said drive member; 
 ii) an output member rotatable with said camshaft wherein said output member is rotatable relative to said input member by oil from said oil supply, thereby varying the phase relationship between said crankshaft and said camshaft; and 
 iii) a valve spool within said camshaft phaser and moveable therein between 1) an advance position to direct oil from said oil supply to cause said input member to rotate relative to said output member to advance said camshaft relative to said crankshaft and 2) a retard position to direct oil from said oil supply to cause said input member to rotate relative to said output member to retard said camshaft relative to said crankshaft; 
   e) an actuator for moving said valve spool between said advance position and said retard position; and   f) a sealing arrangement defining a dry zone with one of said engine cover and said actuator to isolate said drive member from oil used to rotate said output member relative to said input member.   
     
     
         2 . An internal combustion engine as in  claim 1  wherein:
 said input member is a stator having a plurality of lobes; 
 said output member is a rotor disposed within said stator, said rotor having a plurality of vanes interspersed with said lobes such that said rotor is rotatable within said stator about said camshaft axis and defining alternating advance chambers and retard chambers, wherein said advance chambers receive oil in order to change the phase relationship between said crankshaft and said camshaft in an advance direction and said retard chambers receive oil in order to change the phase relationship between said camshaft and said crankshaft in a retard direction; 
 said camshaft phaser further comprising a front cover closing off one end of said stator; and 
 said sealing arrangement comprising an engine cover to camshaft phaser seal to seal between said engine cover and said front cover or between said actuator and said front cover. 
 
     
     
         3 . An internal combustion engine as in  claim 2  wherein said engine cover to camshaft phaser seal is a radial seal. 
     
     
         4 . An internal combustion engine as in  claim 2  wherein said camshaft phaser rotates relative to said engine cover to camshaft phaser seal. 
     
     
         5 . An internal combustion engine as in  claim 2  wherein said engine cover includes a ring-shaped engine cover seal support extending axially from said engine cover toward said camshaft phaser and said engine cover to camshaft phaser seal is fixed to said engine cover seal support. 
     
     
         6 . An internal combustion engine as in  claim 5  wherein said front cover includes a ring-shaped front cover sealing body extending axially from said front cover toward said engine cover such that said engine cover to camshaft phaser seal seals against said front cover sealing body. 
     
     
         7 . An internal combustion engine as in  claim 2  wherein:
 said camshaft phaser further comprises a back cover closing off the other end of said stator, said back cover including a back cover central bore extending axially therethrough; 
 said internal combustion engine further comprising a camshaft support which supports said camshaft; and 
 said sealing arrangement further comprising an engine to camshaft phaser seal to seal between said camshaft phaser and said camshaft support. 
 
     
     
         8 . An internal combustion engine as in  claim 7  wherein said engine to camshaft phaser seal is a radial seal. 
     
     
         9 . An internal combustion engine as in  claim 7  wherein said camshaft phaser rotates relative to said engine to camshaft phaser seal. 
     
     
         10 . An internal combustion engine as in  claim 7  wherein said camshaft support defines a camshaft support bore and said engine to camshaft phaser seal is located within said camshaft support bore. 
     
     
         11 . An internal combustion engine as in  claim 10  wherein said back cover includes a ring-shaped back cover sealing body extending axially from said back cover into said camshaft support bore such that said engine to camshaft phaser seal seals against said back cover sealing body. 
     
     
         12 . An internal combustion engine as in  claim 2  wherein said engine cover to camshaft phaser seal is fixed to said actuator. 
     
     
         13 . An internal combustion engine as in  claim 12  wherein said actuator includes an actuator seal bore extending axially into said actuator and said engine cover to camshaft phaser seal is fixed within said actuator seal bore. 
     
     
         14 . An internal combustion engine having a crankshaft rotatable about a crankshaft axis and a camshaft rotatable by said crankshaft about a camshaft axis, said internal combustion engine comprising:
 a) an oil supply;   b) an engine cover;   c) a drive member disposed within said engine cover for transferring rotational motion from said crankshaft to said camshaft;   d) a camshaft phaser disposed within said engine cover for controllably varying the phase relationship between said crankshaft and said camshaft, said camshaft phaser comprising:
 i) an input member driven by said drive member; 
 ii) an output member rotatable with said camshaft wherein said output member is rotatable relative to said input member by oil from said oil supply, thereby varying the phase relationship between said crankshaft and said camshaft; and 
 iii) a valve spool within said camshaft phaser and moveable therein for directing oil from said oil supply; 
   e) an actuator for moving said valve spool; and   f) a sealing arrangement defining a dry zone with one of said engine cover and said actuator to isolate said drive member from oil directed by said valve spool.   
     
     
         15 . An internal combustion engine as in  claim 14  wherein:
 said input member is a stator having a plurality of lobes; 
 said output member is a rotor disposed within said stator, said rotor having a plurality of vanes interspersed with said lobes such that said rotor is rotatable within said stator about said camshaft axis and defining alternating advance chambers and retard chambers, wherein said advance chambers receive oil in order to change the phase relationship between said crankshaft and said camshaft in an advance direction and said retard chambers receive oil in order to change the phase relationship between said camshaft and said crankshaft in a retard direction; 
 said camshaft phaser further comprising a front cover closing off one end of said stator; and 
 said sealing arrangement comprising an engine cover to camshaft phaser seal to seal between said engine cover and said front cover or between said actuator and said front cover. 
 
     
     
         16 . An internal combustion engine as in  claim 15  wherein said engine cover includes a ring-shaped engine cover seal support extending axially from said engine cover toward said camshaft phaser and said engine cover to camshaft phaser seal is fixed to said engine cover seal support. 
     
     
         17 . An internal combustion engine as in  claim 15  wherein said front cover includes a ring-shaped front cover sealing body extending axially from said front cover toward said engine cover such that said engine cover to camshaft phaser seal seals against said front cover sealing body. 
     
     
         18 . An internal combustion engine as in  claim 15  wherein:
 said camshaft phaser further comprises a back cover closing off the other end of said stator, said back cover including a back cover central bore extending axially therethrough; 
 said internal combustion engine further comprising a camshaft support which supports said camshaft; and 
 said sealing arrangement further comprising an engine to camshaft phaser seal to seal between said camshaft phaser and said camshaft support. 
 
     
     
         19 . An internal combustion engine as in  claim 18  wherein said camshaft support defines a camshaft support bore and said engine to camshaft phaser seal is located within said camshaft support bore. 
     
     
         20 . An internal combustion engine as in  claim 19  wherein said back cover includes a ring-shaped back cover sealing body extending axially from said back cover into said camshaft support bore such that said engine to camshaft phaser seal seals against said back cover sealing body. 
     
     
         21 . An internal combustion engine as in  claim 15  wherein said engine cover to camshaft phaser seal is fixed to said actuator. 
     
     
         22 . An internal combustion engine as in  claim 21  wherein said actuator includes an actuator seal bore extending axially into said actuator and said engine cover to camshaft phaser seal is fixed within said actuator seal bore.