Patent ID: 8002097

Claim:
A clutch mechanism for an outboard motor comprising: a forward gear and a reverse gear arranged to rotate freely around an output shaft to drive a propeller, each of the forward gear and the reverse gear including an input gear driven by a drive gear on a drive shaft so as to rotate in opposite directions; and a dog gear disposed around the output shaft between the forward gear and the reverse gear, the dog gear arranged to be movable in an axial direction relative to the output shaft and to be rotationally immovable in a circumferential direction relative to the output shaft; wherein a plurality of engaging projections on engaging areas of the forward gear and the reverse gear are arranged to be engaged with a plurality of engaging recesses on engaging areas of the dog gear; the dog gear is arranged to be engaged with either the forward gear or with the reverse gear resulting in the plurality of engaging recesses being engaged with the plurality of engaging projections to drive the output shaft; the engaging projections and the engaging recesses are located radially inside the input gears, and include at least seven and no more than ten of the engaging projections and the engaging recesses, respectively, in a row along a circumference of the forward gear, the reverse gear, and the dog gear; the engaging projections and the engaging recesses are located radially outside of a center axis of the output shaft in a range of about 20 mm to about 32 mm from the center axis; at the time of engagement, a transmitted torque is dispersed to driving force transmitting surfaces defined by surfaces of the engaging projections and the engaging recesses facing each other in the circumferential direction; and a sloping portion is arranged on tops of engaging portions between the engaging recesses of the dog gear and at least one of tops of the engaging projections of the forward gear and tops of the engaging projections of the reverse gear to guide the engaging projections into the engaging recesses.