Motorcycle camshaft drive tensioner

Abstract

A cam drive tensioner for use with an engine includes a main body mounted to a component of the engine; a shoe movably mounted to the main body, for movement in a first direction; and two or more hydraulic chambers defined between the main body and the shoe, with the two or more hydraulic chambers being laterally spaced apart from each other in a second direction generally perpendicular to the first direction.

1 . A cam drive tensioner for use with an engine, comprising:
 a main body mounted to a component of the engine;   a shoe movably mounted to the main body, for movement in a first direction; and   two or more hydraulic chambers defined between the main body and the shoe, with the two or more hydraulic chambers being laterally spaced apart from each other in a second direction generally perpendicular to the first direction.   
     
     
         2 . The tensioner according to  claim 1 , wherein the main body is mounted to a camshaft support plate. 
     
     
         3 . The tensioner according to  claim 1 , wherein the engine has at least one cam drive chain, and the two or more hydraulic chambers receive pressurized fluid and bias the shoe toward the cam drive chain. 
     
     
         4 . The tensioner according to  claim 1 , wherein the main body has an inlet port, and each hydraulic chamber comprises a hydraulic component which comprises a respective piston in fluid communication with the inlet port. 
     
     
         5 . The tensioner according to  claim 4 , wherein the main body has a floor, and each piston has a hollow interior region, and a first fluid chamber is formed by the hollow interior region and the floor. 
     
     
         6 . The tensioner according to  claim 5 , wherein each piston has a respective top port, and a cylinder cap is disposed over the top port and in contact with the shoe. 
     
     
         7 . The tensioner according to  claim 6 , further comprising a respective one-way check valve located at each top port. 
     
     
         8 . A cam drive tensioner for use with an engine having a cam drive chain, the tensioner comprising:
 a main body having a main fluid inlet port and a floor having a first piston mounting surface and a second piston mounting surface, with the first piston mounting surface having a first port in fluid communication with the main fluid inlet port, and the second piston mounting surface having a second port in fluid communication with the main fluid inlet port;   a first piston having a first top end and a first open bottom end that forms a first fluid chamber in combination with the first piston mounting surface;   a second piston having a first top end and an second open bottom end that forms a second fluid chamber in combination with the second piston mounting surface; and   a shoe movable with respect to the main body, with the first and second pistons each disposed in between the shoe and the main body so that fluid pressure applied to the mail fluid inlet port urges the shoe away from the main body.   
     
     
         9 . The tensioner according to  claim 8 , wherein the shoe is movable with respect to the main body in a first direction, the first piston is aligned parallel to the second piston, and the first piston is laterally offset from the second piston in a direction perpendicular to the first direction. 
     
     
         10 . The tensioner according to  claim 8 , wherein the shoe has a first recess and a second recess, and the tensioner further comprises:
 a first cylinder cap disposed in the first recess; and   a second cylinder cap disposed in the second recess.   
     
     
         11 . The tensioner according to  claim 10 , wherein the first piston has a first outlet port and the second piston has a second outlet port. 
     
     
         12 . The tensioner according to  claim 11 , wherein the first cylinder cap extends partially over the first piston and has a first hollow interior region that receives fluid pressure from the first outlet port, and wherein the second cylinder cap extends partially over the second piston and has a second hollow interior region that receives fluid pressure from the second outlet port. 
     
     
         13 . The tensioner according to  claim 12 , further comprising a first check valve located adjacent the first outlet port and a second cheek valve located adjacent the second outlet port. 
     
     
         14 . The tensioner according to  claim 12 , further comprising a first spring disposed between the first piston and the first cylinder cap and a second spring disposed between the second piston and the second cylinder cap. 
     
     
         15 . The tensioner according to  claim 8 , wherein the first fluid chamber and the second fluid chamber are in fluid communication with each other and with the main fluid inlet port. 
     
     
         16 . A cam drive tensioner for use with an engine, comprising:
 a main body mounted to a component of the engine;   a shoe movably mounted to the main body, for movement in a first direction; and means for biasing the shoe away from the main body, and for contacting the shoe at two or more contact locations on the shoe, with the two or more contact locations each being spaced apart from each other.   
     
     
         17 . The tensioner according to  claim 16 , wherein the two or more contact locations are spaced apart in a second direction perpendicular to the first direction. 
     
     
         18 . A cam drive tensioner for use with an engine, comprising:
 a main body mounted to a component of the engine;   a shoe movably mounted to the main body, for movement in a first direction, the shoe defining a first bore defined into the shoe and a second bore defined into the shoe;   a first hydraulic component that is received in the first bore; and   a second hydraulic component that is received in the second bore.   
     
     
         19 . The tensioner according to  claim 18 , wherein the first hydraulic component comprises a first piston and the second hydraulic component comprises a second piston. 
     
     
         20 . The tensioner according to  claim 19 , wherein the first hydraulic component further comprises a first cylinder cap, and the second hydraulic component comprises a second cylinder cap. 
     
     
         21 . A motorcycle engine, comprising:
 at least one camshaft;   a camshaft support plate; and   a cam drive tensioner, comprising:
 a main body mounted to the camshaft support plate; 
 a shoe movably mounted to the main body, for movement in a first direction; and 
 two or more hydraulic components mounted between the main body and the shoe, with the two or more hydraulic components being laterally spaced apart from each other in a second direction generally perpendicular to the first direction. 
   
     
     
         22 . A shoe for use with a motorcycle cam drive chain tensioner, the shoe comprising:
 a shoe element having a first surface adapted to contact then cam drive chain and a second surface opposite the first surface, with two bores defined into the element on the second surface.   
     
     
         23 . A motorcycle engine, comprising:
 at least one camshaft;   a camshaft support plate;   a cam drive having a cam chain; and   a cam drive tensioner mounted to the camshaft support plate, comprising:
 a main body having a first fluid inlet port and a second fluid inlet port, with said first and second fluid inlet ports being in fluid communication with each other, and a floor having a first piston mounting surface and a second piston mounting surface, with the first piston mounting surface having a first fluid outlet port in fluid communication with the first fluid inlet port, and the second piston mounting surface having a second fluid outlet port in fluid communication with the second fluid inlet port; 
 a first piston having a first top end and a first open bottom end that forms a first fluid chamber in combination with the first piston mounting surface; 
 a second piston having a second top end and an second open bottom end that forms a second fluid chamber in combination with the second piston mounting surface; and 
 a shoe movable with respect to the main body, with the first and second pistons each disposed in between the shoe and the main body so that fluid pressure applied to the first and second fluid inlet ports urges the shoe away from the main body. 
   
     
     
         24 . A cam drive tensioner for use with an engine having a cam drive chain, the tensioner comprising:
 a main body defining a shoe receptacle having an oval shaped side wall, a first fluid inlet port and a second fluid inlet port, and a floor having a first piston mounting surface and a second piston mounting surface, with the first piston mounting surface having a first fluid outlet port in fluid communication with the first fluid inlet port, and the second piston mounting surface having a second fluid outlet port in fluid communication with the second fluid inlet port;   a first piston having a first top end and a first open bottom end that forms a first fluid chamber in combination with the first piston mounting surface;   a second piston having a second top end and an second open bottom end that forms a second fluid chamber in combination with the second piston mounting surface; and   a shoe movable with respect to the main body, and a portion of the shoe having an oval shaped side surface complementary to and smaller than the oval shaped receptacle side wall, and the shoe portion adapted to be seated within the receptacle side wall and movable with respect to the shoe, and with the first and second pistons each disposed in between the shoe and the main body so that fluid pressure applied to the main inlet port urges the shoe away from the main body.   
     
     
         25 . The tensioner according to  claim 24 , wherein the first piston mounting surface has a first fluid outlet port in fluid communication with the main fluid inlet port, and the second piston mounting surface has a second fluid outlet port in fluid communication with the main fluid inlet port. 
     
     
         26 . The tensioner according to  claim 24 , wherein the first and second pistons are each cylindrical in shape about a respective central axis. 
     
     
         27 . The tensioner according to  claim 26 , wherein the receptacle side wall oval shape and the shoe side surface oval shape each are symmetrical about a center line; and each oval shape has ends at opposite sides of the center line with a partially circular radius concentric with the respective piston central axis. 
     
     
         28 . The tensioner according to  claim 24 , wherein the main body has a main fluid inlet port and the first and second inlet ports are each in fluid communication with the main fluid inlet port.