The present invention discloses a mechanism that transfers an oscillating rotation into a unidirectional rotation. In one embodiment, the present invention discloses a spur gearing mechanism using spur gears. In another embodiment, the present invention discloses a bevel gearing mechanism using bevel gears, which reduces the total number of gears in comparison the spur gearing mechanism.

.[.The present invention discloses a.]. .Iadd.A .Iaddend.bidirectional mechanical converting unit.[., comprising.]. .Iadd.includes.Iaddend.: a main shaft; a driving mechanism, which including a driving .[.means.]. .Iadd.assembly .Iaddend.and a reversing .[.means.]. .Iadd.assembly .Iaddend.which are coupled to each other; and a rotation .[.means.]. .Iadd.assembly .Iaddend.for inputting torque, an rotation axis of the rotation .[.means.]. .Iadd.assembly .Iaddend.being coaxial with the main shaft, the rotation .[.means.]. .Iadd.assembly .Iaddend.and the driving mechanism being coupled to each other, and the driving mechanism delivering the torque to output at the main shaft at a predetermined direction, no matter in which direction the rotation .[.means.]. .Iadd.assembly .Iaddend.rotates; wherein the predetermined direction can be switched via the reversing .[.means.]. .Iadd.assembly.Iaddend.. .[.The present invention is simple structured, not only can efficiently utilizes the movements of the rotation means in either way, but also can switch the rotation direction of the output shaft conveniently upon demand, with easy operations..].

Disclosed herein is a joint unit including two facing gears that include respective two bevel gear members that face each other, and an intermediate gear that has a bevel gear member meshing with both the two bevel gear members. One of the two facing gears and the intermediate gear includes a first member including an inner circumferential portion of the bevel gear member of the one of the two facing gears and the intermediate gear; a second member including an outer circumferential portion of the bevel gear member of the one of the two facing gears and the intermediate gear; and a resilient member attached to one of the first member and the second member for normally urging the other of the first member and the second member to move in a direction along the directions of rotation of the one of the two facing gears and the intermediate gear.

A forward/backward switching mechanism having an intermediate gear supported by an intermediate shaft perpendicular to a drive shaft is interposed between first and second input shafts. A clutch body is a dog clutch having upper and lower locking dogs. As the dog clutch moves along an axial direction of the second input shaft and is engaged with upper or lower gears, rotation of the first input shaft is forwardly or reversely transmitted to the second input shaft.

In one embodiment, an outboard marine engine comprises the internal combustion engine and a propulsor that is driven into rotation by the internal combustion engine so as to effect a thrust. The outboard marine engine further includes a transmission that shifts amongst a fourth gear wherein the thrust is forward thrust, a reverse gear wherein the thrust is a reverse thrust, and a neutral gear wherein the thrust is a zero thrust. The outboard marine engine further includes a shift rod that is rotatable about its own axis, wherein rotation of the shift rod about its own axis shifts the transmission amongst the forward gear, the reverse gear, and the neutral gear. An actuator operably connects to the internal combustion engine and causes rotation of a gear shaft. At least one gearset connects the gear shaft to the shift rod such that rotation of the gear shaft about its own axis rotates the shift rod about its own axis.

Disclosed herein is a joint unit including two facing gears that include respective two bevel gear members that face each other, and an intermediate gear that has a bevel gear member meshing with both the two bevel gear members. One of the two facing gears and the intermediate gear includes a first member including an inner circumferential portion of the bevel gear member of the one of the two facing gears and the intermediate gear; a second member including an outer circumferential portion of the bevel gear member of the one of the two facing gears and the intermediate gear; and a resilient member attached to one of the first member and the second member for normally urging the other of the first member and the second member to move in a direction along the directions of rotation of the one of the two facing gears and the intermediate gear.

A shift device for an outboard motor includes a forward gear and a reverse gear; a clutch gear; a shift actuator configured to move between a neutral reference position where the clutch gear is disengaged from the forward gear and the reverse gear and an engagement reference position where the clutch gear is engaged with the forward gear or the reverse gear; and a control device configured to control a movement of the shift actuator. The control device is configured to set an intermediate target position, and to set a speed at which the shift actuator moves from the intermediate target position to the engagement reference position slower than a speed at which the shift actuator moves from the neutral reference position to the intermediate target position.

An gear case assembly for a watercraft propulsion system has a gear case housing, a driveshaft with a partially threaded bore defined in an end thereof, and a propeller shaft. The propeller shaft and the driveshaft are angled relative to each other. A bevel gear is mounted to the propeller shaft. A pinion mounted to the end of the driveshaft. The pinion meshes with the bevel gear. The pinion defines a central aperture. A fastener is disposed at least in part in the central aperture of the pinion. The fastener fastens the pinion to the end of the driveshaft. The fastener has a head and a shank. The shank is at least partially threaded. The shank extends into the bore of the driveshaft. An outboard motor having the gear case assembly is also disclosed.

A multi-plate clutch transmission includes an arrangement for selectively engaging the clutch by moving the sleeve to cause one or more friction disks on a sleeve connected to a shaft to move into contact with one or more friction disks on a clutch basket connected to a gear driven by another gear and another shaft driven by a prime mover. An arrangement for selectively disengaging the clutch is provided that uses prime mover torque to move the one or more friction disks on the sleeve out of contact with the one or more.friction disks on the clutch basket.

An outboard motor includes an oil passage that through which an oil flows from the shift chamber to a gear chamber. A circular recessed portion is formed on an upper surface of the gear chamber. A rectangular recessed portion communicating with the circular recessed portion is formed on a portion of the upper surface adjacent to the circular recessed portion. The rectangular recessed portion includes a front surface facing a side surface of the circular recessed portion, a left surface located on a reverse side of a rotation direction of the drive gear with respect to the front surface, and a right surface located on a side of the rotation direction with respect to the front surface. An outlet of the oil passage is arranged on the front surface at a position closer to the left surface than to the right surface.