Drivetrain and Transmission for Marine Propulsion Device for Preventing Engine Ingestion of Water

Abstract

A drivetrain for a marine propulsion device includes an engine driving a crankshaft in a first direction, and a driveshaft connected in torque-transmitting relationship with the crankshaft and supported for rotation about a driveshaft axis. The drivetrain further includes a propeller shaft rotatable about a propeller shaft axis. A gearset and a selector clutch are configured to couple the propeller shaft and the driveshaft to each other in torque-transmitting relationship. A one-way clutch is disposed along the drivetrain upstream of the gearset. The one-way clutch prevents rotation of the crankshaft in a second, opposite direction so as to prevent ingestion of water by the engine via an engine exhaust system.

1 . A drive train for a marine propulsion device, comprising:
 an engine driving a crankshaft in a first direction;   a driveshaft connected in torque-transmitting relationship with the crankshaft and supported for rotation about a driveshaft axis;   a propeller shaft rotatable about a propeller shaft axis;   a gear set and a selector clutch configured to couple the propeller shaft and the driveshaft to each other in torque-transmitting relationship; and   a one-way clutch disposed along the drive train upstream of the gear set, the one-way clutch preventing rotation of the crankshaft in a second, opposite direction so as to prevent ingestion of water by the engine via an engine exhaust system;   wherein the one-way clutch is disposed about the driveshaft in a driveshaft passageway that extends through a gearcase of the marine propulsion device;   wherein the gearcase is made of one of steel and aluminum;   wherein, when the gearcase is made of aluminum, the one-way clutch comprises an outer raceway that is keyed to an inner surface of the driveshaft passageway, and an inner surface of the outer raceway provides a jamming surface for a plurality of wedging elements of the one-way clutch; and   wherein, when the gearcase is made of steel, the one way-clutch is seated directly in the driveshaft passageway, and the inner surface of the driveshaft passageway provides the jamming surface for the plurality of wedging elements of the one-way clutch.   
     
     
         2 - 4 . (canceled) 
     
     
         5 . The drive train of  claim 1 , wherein the marine propulsion device is a sterndrive. 
     
     
         6 . The drive train of  claim 1 , wherein the marine propulsion device is an outboard motor. 
     
     
         7 . (canceled) 
     
     
         8 . The drive train of  claim 1 , wherein the gear set comprises:
 a forward gear disposed for rotation about the propeller shaft axis;   a reverse gear disposed for rotation about the propeller shaft axis; and   a drive gear attached for rotation with the driveshaft, the forward and reverse gears being disposed in meshing relation with the drive gear for rotation in opposite directions from each other about the propeller shaft axis;   wherein the selector clutch is attached for rotation with the propeller shaft about the propeller shaft axis and movable between the forward and reverse gears so as to mesh with one of the forward and reverse gears.   
     
     
         9 . The drive train of  claim 1 , wherein the one-way clutch comprises a sprag-type clutch and the plurality of wedging elements comprises sprags. 
     
     
         10 . The drive train of  claim 1 , wherein the one-way clutch comprises a roller-type clutch and the plurality of wedging elements comprises rollers. 
     
     
         11 . A transmission for a marine propulsion device, comprising:
 a propeller shaft rotatable about a propeller shaft axis;   a forward gear disposed for rotation about the propeller shaft axis;   a reverse gear disposed for rotation about the propeller shaft axis;   a driveshaft supported for rotation about a driveshaft axis, the driveshaft axis being generally perpendicular to the propeller shaft axis;   a drive gear attached for rotation with the driveshaft, the forward and reverse gears being disposed in meshing relation with the drive gear for rotation in opposite directions from each other about the propeller shaft axis;   a selector clutch attached for rotation with the propeller shaft about the propeller shaft axis and movable between the forward and reverse gears so as to mesh with one of the forward and reverse gears; and   a one-way clutch disposed about the driveshaft in a driveshaft passageway that extends through a gearcase of the marine propulsion device, the one-way clutch allowing rotation of the driveshaft about the driveshaft axis in a first direction by application of torque from an engine coupled to the driveshaft, and preventing rotation of the driveshaft about the driveshaft axis in a second, opposite direction by application of torque transmitted from the propeller shaft to the driveshaft via the selector clutch, one of the forward and reverse gears, and the drive gear;   wherein the gearcase is made of one of steel and aluminum;   wherein, when the gearcase is made of aluminum, the one-way clutch comprises an outer raceway that is keyed to an inner surface of the driveshaft passageway, and an inner surface of the outer raceway provides a jamming surface for a plurality of wedging elements of the one-way clutch; and   wherein, when the gearcase is made of steel, the one way-clutch is seated directly in the driveshaft passageway, and the inner surface of the driveshaft passageway provides the jamming surface for the plurality of wedging elements of the one-way clutch.   
     
     
         12 - 13 . (canceled) 
     
     
         14 . The transmission of  claim 11 , wherein the one-way clutch is located in an upper half of the gearcase. 
     
     
         15 . The transmission of  claim 14 , wherein the one-way clutch is located directly below an upper surface of the gearcase that is configured to be coupled to a driveshaft housing of the marine propulsion device. 
     
     
         16 - 17 . (canceled) 
     
     
         18 . The transmission of  claim 11 , wherein the marine propulsion device is an outboard motor. 
     
     
         19 . The transmission of  claim 11 , wherein the one-way clutch comprises a sprag-type clutch and the plurality of wedging elements comprises sprags. 
     
     
         20 . The transmission of  claim 11 , wherein the one-way clutch comprises a roller-type clutch and the plurality of wedging elements comprises rollers.