Shift mechanism for marine propulsion unit

A marine propulsion unit comprising a prime mover, a first shaft driven by the prime mover, a second shaft driven by the first shaft, the second shaft driving a propulsion device, the first shaft carrying a first gear, the second shaft carrying second and third gears, the first gear always meshing with the second and third gears, the first gear driving the second and third gears in opposite directions relative to each other, a first hydraulic clutch mechanism configured to couple the second gear with the second shaft, a second hydraulic clutch mechanism configured to couple the third gear with the second shaft, and a hydraulic control system selectively operating either the first hydraulic clutch mechanism or the second hydraulic clutch mechanism, the first hydraulic clutch mechanism being coupled with the hydraulic control system through a first fluid passage, the second hydraulic clutch mechanism being coupled with the hydraulic control system through a second fluid passage, at least a portion of the first fluid passage or a portion of the second fluid passage being defined within the second shaft.

A marine propulsion unit comprising a prime mover, a first shaft driven by the prime mover, a second shaft driven by the first shaft, the second shaft driving a propulsion device, the first shaft carrying a first gear, the second shaft carrying second and third gears, the first gear always meshing with the second and third gears, the first gear driving the second and third gears in opposite directions relative to each other, a first hydraulic clutch mechanism configured to couple the second gear with the second shaft, a second hydraulic clutch mechanism configured to couple the third gear with the second shaft, a hydraulic control system selectively operating either the first hydraulic clutch mechanism or the second hydraulic clutch mechanism, a fluid pump configured to pressurize a working fluid for at least one of the first and second hydraulic clutch mechanisms, an axis of the first shaft extending generally vertically within a vertical plane, the vertical plane also passing through the fluid pump and the propulsion device, and an exhaust system defining a conduit that extends generally parallel to the first shaft, and the fluid pump being positioned on a side of the first shaft opposite to the conduit of the exhaust system.

A marine propulsion unit comprising a first shaft, a second shaft selectively driven by the first shaft to drive a propulsion device, a first gear carried by the first shaft, a second gear carried by the second shaft and continuously driven by the first gear, a hydraulic clutch mechanism operating between the second gear and the second shaft so as to drivingly couple the second gear with the second shaft, a hydraulic control system selectively actuating the hydraulic clutch mechanism, the hydraulic clutch mechanism being coupled with the hydraulic control system through a fluid passage, at least a portion of the fluid passage being defined within the second shaft, and a prime mover configured to drive the first shaft, a fluid pump configured to pressurize a working fluid for the hydraulic clutch mechanism, a coolant pump configured to supply coolant to the prime mover, and a partition arranged to separate the fluid pump and the coolant pump from each other, the first shaft extending through the partition.

A marine propulsion unit comprising a first shaft, a second shaft selectively driven by the first shaft to drive a propulsion device, a first gear carried by the first shaft, a second gear carried by the second shaft and continuously driven by the first gear, a hydraulic clutch mechanism operating between the second near and the second shaft so as to drivingly couple the second gear with the second shaft, a hydraulic control system selectively actuating the hydraulic clutch mechanism, the hydraulic clutch mechanism being coupled with the hydraulic control system through a fluid passage, at least a portion of the fluid passage being defined within the second shaft, and a third gear supported by the second shaft and continuously driven by the first gear, and another hydraulic clutch mechanism operating between the third gear and the second shaft, the hydraulic control system selectively actuating the hydraulic clutch mechanism, wherein the second shaft supports the second gear.

A marine propulsion unit comprising a first shaft, a second shaft selectively driven by the first shaft to drive a propulsion device, a first gear carried by the first shaft, a second rear carried by the second shaft and continuously driven by the first gear, a hydraulic clutch mechanism operating between the second gear and the second shaft so as to drivingly couple the second sear with the second shaft, a hydraulic control system selectively actuating the hydraulic clutch mechanism, the hydraulic clutch mechanism being coupled with the hydraulic control system through a fluid passage, at least a portion of the fluid passage being defined within the second shaft, and a fluid pump configured to pressurize a working fluid for the hydraulic clutch mechanism, an engine driving the first shaft, and an exhaust conduit through which exhaust gases from the engine pass, the fluid pump and the exhaust conduit being positioned opposite to each other relative to the first shaft.