Outboard motor
An outboard motor includes a drive shaft, a coupling to connect a first shaft and a second shaft of the drive shaft together, and a transmission including a dog clutch to transmit a rotation of the drive shaft to a propeller shaft. The coupling includes a first portion attached to the first shaft, a second portion attached to the second shaft, and a damper. The first portion includes first claws arranged along a rotation direction of the drive shaft. The second portion includes second claws between adjacent ones of the first claws in the rotation direction. The damper includes an elastic portion interposed between adjacent ones of the first claws and the second claws in the rotation direction.
1. An outboard motor comprising:
an engine;
a propeller shaft that is rotatable together with a propeller;
a drive shaft divided into a first shaft and a second shaft that is farther away from the engine than the first shaft and that is rotated by power of the engine;
a coupling to connect the first shaft and the second shaft together; and
a transmission to transmit rotation of the drive shaft to the propeller shaft, the transmission including:
a rotary body that is rotatable interlockingly with rotation of the second shaft; and
a dog clutch that is rotatable interlockingly with the propeller shaft and movable between a connection position to engage with the rotary body and a disconnection position to disengage from the rotary body; wherein
the coupling includes:
a first portion attached to the first shaft and including a plurality of first claws arranged along a rotation direction of the drive shaft;
a second portion attached to the second shaft and including a plurality of second claws arranged between adjacent ones of the plurality of first claws in the rotation direction; and
a damper including an elastic portion interposed between a first claw of the plurality of first claws and a second claw of the plurality of second claws that is adjacent to the first claw in the rotation direction;
the damper includes a plurality of the elastic portions arranged along the rotation direction;
the plurality of elastic portions are interposed between adjacent ones of the plurality of first claws and the plurality of second claws in the rotation direction;
the first claw includes a first inward portion and a first outward portion, the first inward portion is located between adjacent ones of the plurality of elastic portions in the rotation direction, and the first outward portion extends in the rotation direction from an outer end portion of the first inward portion and faces inward toward the elastic portion in a radial direction of the drive shaft;
the second claw includes a second inward portion and a second outward portion, the second inward portion is located between adjacent ones of the elastic portions in the rotation direction, and the second outward portion extends in the rotation direction from an outer end portion of the second inward portion and faces inward toward the elastic portion in the radial direction;
the first inward portion and the second inward portion are alternately arranged along the rotation direction; and
the first outward portion and the second outward portion are alternately arranged along the rotation direction.
2. The outboard motor according to claim 1 , wherein the damper includes a base portion, and the plurality of elastic portions are integral with the base portion, extend along the radial direction of the drive shaft, and arranged radially around the drive shaft.
3. The outboard motor according to claim 1 , wherein
the outer end portion of the first inward portion is connected to a center or an end portion of the first outward portion in the rotation direction; and
the outer end portion of the second inward portion is connected to a center or an end portion of the second outward portion in the rotation direction.
4. The outboard motor according to claim 1 , wherein an angular range of the elastic portion in the rotation direction is equal to or less than an angular interval between adjacent ones of the first inward portion and the second inward portion in the rotation direction, and is equal to or more than an angular interval between adjacent ones of the first outward portion and the second outward portion in the rotation direction.
5. The outboard motor according to claim 1 , wherein
the propeller shaft is located at a lower position than the engine;
the drive shaft extends in an up-down direction between the propeller shaft and the engine;
the second shaft is located at a lower position than the first shaft;
the second shaft is divided into a third shaft to which the second portion is attached and a fourth shaft that is located at a lower position than the third shaft and that is connected to the transmission; and
at least the propeller, the propeller shaft, the transmission, and the fourth shaft define a lower assembly in the outboard motor.
6. The outboard motor according to claim 1 , further comprising a propeller damper interposed between the propeller and the propeller shaft.
7. The outboard motor according to claim 1 , wherein
the rotary body includes a first rotary body and a second rotary body arranged side by side in an axial direction of the propeller shaft and that rotate in mutually opposite directions around a rotational axis of the propeller shaft;
the dog clutch is movable along the axial direction; and
the connection position includes a first connection position at which the dog clutch engages with only the first rotary body and a second connection position at which the dog clutch engages with only the second rotary body.