Spur gear drive for an internal combustion engine

Abstract

In a spur gear drive for driving the camshaft of an overhead valve internal combustion engine wherein drive power is transmitted from the crankshaft to the camshaft via spur gears mounted on the crankshaft and the camshaft which is rotatably supported on the cylinder head, a third, intermediate, gear is adjustably supported in the power train between engine block-mounted gears and cylinder head-mounted gears so that changes in the distance between the crankshaft and the camshaft can be accommodated and, with the use of smaller gears, the spur gear drive becomes smaller and lighter overall.

1 . Spur gear drive for an internal combustion engine having an engine block and a cylinder head with a crankshaft ( 101 ) mounted on the cylinder block and, a crankshaft gear ( 102 ;  202 ) mounted on the crankshaft ( 101 ), at least camshaft with a first camshaft gear ( 112 ;  212 ) mounted on the cylinder head, a first intermediate gear ( 104 ;  204 ) disposed in engagement with the crankshaft gear ( 102 ,  202 ) a second intermediate gear ( 106 ;  206 ) in engagement with the first intermediate gear ( 104 ,  204 ), and a third intermediate gear ( 108 ;  208 ) in engagement with the second intermediate gear ( 106 ,  206 ) for transmitting motion from the crankshaft ( 101 ) to the camshaft ( 112 ). 
   
   
       2 . A spur gear drive according to  claim 1 , wherein an oil pump gear ( 116 ;  216 ) is provided which is arranged, with respect to the crankshaft axis, at a side of the crankshaft gear ( 102 ,  202 ) opposite the camshaft gear ( 112 ,  212 ). 
   
   
       3 . A spur gear drive according to  claim 2 , wherein the oil pump gear ( 116 ) is driven by the crankshaft gear ( 102 ) via an oil pump intermediate gear ( 118 ). 
   
   
       4 . A spur gear drive according to  claim 1 , wherein a fuel pump gear drive ( 122 ,  222 ) is provided in engagement with one of the second and third gears ( 106 ;  206 ) to be driven thereby. 
   
   
       5 . A spur gear drive according to  claim 4 , wherein the fuel pump gear ( 122 ) is in engagement with the second intermediate gear ( 106 ) so as to be driven by means of the first and the second intermediate gears ( 104 ,  106 ). 
   
   
       6 . A spur gear drive according to  claim 1 , wherein a turbo-compound gear ( 124 ;  224 ) is provided. 
   
   
       7 . A spur gear drive according to  claim 6 , wherein the turbo-compound gear ( 124 ;  224 ) is driven by means of a turbocompound intermediate gear ( 126 ;  226 ). 
   
   
       8 . A spur gear drive according to  claim 1 , wherein a compressor gear ( 120 ;  220 ) is provided. 
   
   
       9 . A spur gear drive according to  claim 8 , wherein the compressor gear ( 120 ;  220 ) is driven by the first intermediate gear ( 104 ;  204 ). 
   
   
       10 . A spur gear drive according to  claim 1 , wherein the first intermediate gear ( 104 ) is a single gear with only one toothing. 
   
   
       11 . A spur gear drive according to  claim 1 , wherein the turbo-compound intermediate gear ( 126 ) is a single gear with only one toothing. 
   
   
       12 . A spur gear drive according to  claim 1 , wherein the second intermediate gear ( 106 ) is a double gear with two toothings. 
   
   
       13 . A spur gear drive according to  claim 1 , wherein the first intermediate gear ( 204 ) and the third intermediate gear ( 208 ) are double gears with two toothings. 
   
   
       14 . A spur gear drive according to  claim 13 , wherein the turbo-compound intermediate gear ( 226 ) is a double gear with two toothings. 
   
   
       15 . A spur gear drive according to  claim 1 , wherein a second camshaft gear ( 114 ,  214 ) is provided, with the first camshaft gear ( 112 ,  212 ) actuating inlet valve and the second camshaft gear ( 114 ,  214 ) actuating outlet valve. 
   
   
       16 . A spur gear drive according to  claim 15 , wherein a distributor gear is provided as a fourth intermediate gear ( 110 ,  210 ), via which distributor gear the first and the second camshaft gears ( 112 ,  114 ;  212 ,  214 ) are driven by the third intermediate gear ( 108 ;  208 ). 
   
   
       17 . A spur gear drive according to  claim 1 , wherein the third intermediate gear ( 108 ) is arranged in a moveable fashion in order to compensate a variation in the axis spacing of the first camshaft gear ( 112 ) and if appropriate the second camshaft gear ( 114 ) with respect to the second intermediate gear ( 106 ). 
   
   
       18 . A spur gear drive according to  claim 17 , wherein the third intermediate gear ( 108 ) is mounted on an eccentric disc ( 134 ) which can preferably be adjusted by means of a spindle drive ( 140 ,  142 ). 
   
   
       19 . A spur gear drive according to  claim 1 , wherein an intermediate gear ( 208 ) bridging the interface area between the cylinder block and the cylinder head is rotatably supported by a bearing journal ( 232 ) which is eccentrically supported on one of the cylinder block and the cylinder head for adjustment of the distance between the axes of this intermediate gear ( 208 ) and an adjacent gear ( 210 ) supported by the other of the cylinder head and the cylinder block. 
   
   
       20 . A spur gear drive according to  claim 19 , wherein the bearing journal ( 232 ) is mounted by bolts ( 236 ) extending through elongated holes ( 238 ) formed in the bearing journal ( 232 ).