Marine drive unit with a cooling oil circuit

Abstract

The present invention relates to a marine drive unit (1) comprising an upper bevel gear set (2) and a lower bevel gear set (3). The upper bevel gear set (2) is connected to the lower bevel gear set (3) by a drive shaft (4) which extends in vertical direction. A first oil pump (5) is arranged to supply oil to the upper bevel gear set (2) and a second oil pump (6) is arranged to feed a cooling oil circuit.

1 . A marine drive unit ( 1 ) comprising:
 an upper bevel gear set ( 2 );   a lower bevel gear set ( 3 );   a drive shaft extending in a vertical direction and connecting the upper bevel gear set ( 2 ) to the lower bevel gear set ( 3 );   a first oil pump ( 5 ) arranged to supply oil to the upper bevel gear set ( 2 ); and   a second oil pump ( 6 ) arranged to feed a cooling oil circuit.   
     
     
         2 . The marine drive unit according to  claim 1 , comprising:
 at least one pressure operated clutch ( 7 ,  8 ) configured to reverse a rotational direction of the drive shaft ( 4 ) with regard to an input shaft ( 9 ) of the marine drive unit ( 1 ); and   wherein the first oil pump ( 5 ) is arranged to supply pressure for the pressure operated clutch ( 7 ,  8 ).   
     
     
         3 . The marine drive unit according to  claim 1 , wherein the second oil pump ( 6 ) is located at a lower end ( 10 ) of the drive shaft ( 4 ) and defines at least one first opening ( 13 ), the second oil pump configured to suck oil from an oil reservoir ( 11 ) through a bore ( 12 ) in the drive shaft ( 4 ) and to pump it through the at least one first opening ( 13 ) at the second oil pump ( 6 ) back to the oil reservoir ( 11 ). 
     
     
         4 . The marine drive unit according to  claim 1 , wherein the second oil pump ( 6 ) is located at a lower end ( 10 ) of the drive shaft ( 4 ) and defining at least one first opening ( 13 ) and at least one second opening ( 17 ), the second oil pump configured to suck oil from an oil reservoir ( 11 ) through the at least one first opening ( 13 ) at the second oil pump ( 6 ) and to pump it through a bore ( 12 ) in the drive shaft ( 4 ) and through the at least one second opening ( 17 ) back to the oil reservoir ( 11 ). 
     
     
         5 . The marine drive unit according to  claim 3 , comprising an underwater housing defining an inside space, wherein the drive shaft ( 4 ) is arranged at least partially inside the underwater housing ( 14 ) and wherein the inside space of the underwater housing ( 14 ) forms the oil reservoir ( 11 ). 
     
     
         6 . The marine drive unit according to  claim 4 , wherein the drive shaft ( 4 ) comprises an upper shaft section ( 15 ) and a lower shaft section ( 16 ), wherein the bore ( 12 ) in the drive shaft is a central bore in the lower shaft section ( 16 ), and wherein the at least one second opening ( 17 ) is between the oil reservoir ( 11 ) and the bore ( 12 ) and is further positioned between the upper and lower shaft section ( 15 ,  16 ). 
     
     
         7 . The marine drive unit according to  claim 6 , further comprising a sleeve ( 18 ) connecting the upper shaft section ( 15 ) to the lower shaft section ( 16 ), and wherein the at least one second opening ( 17 ) is arranged at the sleeve ( 18 ). 
     
     
         8 . The marine drive unit according to ene  of the preceding claim 1 , wherein the second oil pump ( 6 ) comprises a pump screw ( 19 ) which is arranged co-axially to the bore ( 12 ) in the drive shaft ( 4 ). 
     
     
         9 . The marine drive unit according to  claim 8 , wherein the pump screw ( 19 ) extends at least partially inside the drive shaft ( 4 ). 
     
     
         10 . The marine drive unit according to  claim 1 , wherein the second oil pump ( 6 ) is driven via the drive shaft ( 4 ) and a pair of pump gears ( 20 ,  21 ). 
     
     
         11 . The marine drive unit according to  claim 2 , wherein the second oil pump ( 6 ) is located at a lower end ( 10 ) of the drive shaft ( 4 ) and defines at least one first opening ( 13 ), the second oil pump configured to suck oil from an oil reservoir ( 11 ) through a bore ( 12 ) in the drive shaft ( 4 ) and to pump it through the at least one first opening ( 13 ) at the second oil pump ( 6 ) back to the oil reservoir ( 11 ). 
     
     
         12 . The marine drive unit according to  claim 2 , wherein the second oil pump ( 6 ) is located at a lower end ( 10 ) of the drive shaft ( 4 ) and defining at least one first opening ( 13 ) and at least one second opening ( 17 ) between the oil reservoir and the bore, the second oil pump configured to suck oil from an oil reservoir ( 11 ) through the at least one first opening ( 13 ) at the second oil pump ( 6 ) and to pump it through a bore ( 12 ) in the drive shaft ( 4 ) and through the at least one second opening ( 17 ) back to the oil reservoir ( 11 ). 
     
     
         13 . The marine drive unit according to  claim 12 , wherein the second oil pump ( 6 ) comprises a pump screw ( 19 ) arranged co-axially with the bore ( 12 ) and extending at least partially inside the drive shaft ( 4 ). 
     
     
         14 . The marine drive unit according to  claim 12 , comprising an underwater housing, wherein the drive shaft ( 4 ) is arranged at least partially inside the underwater housing ( 14 ) and wherein an inside space of the underwater housing ( 14 ) forms the oil reservoir ( 11 ). 
     
     
         15 . The marine drive unit according to  claim 14 , wherein the drive shaft ( 4 ) comprises an upper shaft section ( 15 ) and a lower shaft section ( 16 ), wherein the bore ( 12 ) in the drive shaft is a central bore in the lower shaft section ( 16 ), and wherein the at least one second opening ( 17 ) is between the upper and lower shaft section ( 15 ,  16 ). 
     
     
         16 . The marine drive unit according to  claim 15 , further comprising a sleeve ( 18 ) connecting the upper shaft section ( 15 ) to the lower shaft section ( 16 ), and wherein the at least one second opening ( 17 ) is arranged at the sleeve ( 18 ). 
     
     
         17 . The marine drive unit according to  claim 16 , wherein the second oil pump ( 6 ) comprises a pump screw ( 19 ) arranged co-axially with the bore ( 12 ) and extending at least partially inside the drive shaft ( 4 ). 
     
     
         18 . The marine drive unit according to  claim 17 , wherein the second oil pump ( 6 ) is driven via the drive shaft ( 4 ) and a pair of pump gears ( 20 ,  21 ).