Outboard motor and boat
An outboard motor includes an engine, a propeller shaft, a propeller attached to the propeller shaft, a transmission to transmit rotation of the engine to the propeller shaft, an upper accommodation body accommodating at least a portion of the engine, a lower accommodation body accommodating at least a portion of the propeller shaft, and a steering to cause the lower accommodation body to rotate about a steering axis with respect to the upper accommodation body. The upper accommodation body includes an upper coolant channel. The lower accommodation body includes a lower coolant channel including a coolant intake port. A communication area between the upper and lower coolant channels is changeable according to a rudder angle of the steering.
1 . An outboard motor comprising:
an engine;
a propeller shaft;
a propeller attached to the propeller shaft;
a transmission to transmit rotation of the engine to the propeller shaft;
an upper accommodation body that accommodates at least a portion of the engine;
a lower accommodation body that accommodates at least a portion of the propeller shaft; and
a steering to cause the lower accommodation body to rotate about a steering axis with respect to the upper accommodation body; wherein
the upper accommodation body includes an upper coolant channel;
the lower accommodation body includes a lower coolant channel including a coolant intake port;
the upper coolant channel communicates with the lower coolant channel along a direction perpendicular to the steering axis; and
a communication area between the upper coolant channel and the lower coolant channel is changeable according to a rudder angle of the steering.
2 . The outboard motor according to claim 1 , wherein the communication area has a first area value when the rudder angle has a first rudder angle value, and a second area value smaller than the first area value when the rudder angle has a second rudder angle value larger than the first rudder angle value.
3 . The outboard motor according to claim 1 , wherein
one of the upper coolant channel and the lower coolant channel includes a communication port; and
the other of the upper coolant channel and the lower coolant channel includes a plurality of communication ports located along a circumferential direction around the steering axis, a total area of the plurality of communication ports overlapping the communication port being changed according to the rudder angle.
4 . The outboard motor according to claim 3 , wherein the plurality of communication ports includes at least two communication ports, and opening areas of the at least two communication ports differ from each other.
5 . The outboard motor according to claim 3 , wherein the plurality of communication ports are located at unequal intervals along the circumferential direction around the steering axis.
6 . The outboard motor according to claim 3 , wherein an opening area of the communication port is larger than an opening area of the plurality of communication ports.
7 . A boat comprising:
a hull; and
the outboard motor according to claim 1 attached to a rear portion of the hull.
8 . An outboard motor comprising:
an engine;
a propeller shaft;
a propeller attached to the propeller shaft;
a transmission to transmit rotation of the engine to the propeller shaft;
an upper accommodation body that accommodates at least a portion of the engine;
a lower accommodation body that accommodates at least a portion of the propeller shaft; and
a steering to cause the lower accommodation body to rotate about a steering axis with respect to the upper accommodation body; wherein
the upper accommodation body includes an upper coolant channel;
the lower accommodation body includes a lower coolant channel including a coolant intake port;
the upper coolant channel communicates with the lower coolant channel along a direction perpendicular to the steering axis; and
a communication area between the upper coolant channel and the lower coolant channel is changeable according to a rudder angle of the steering or a speed of the engine.
9 . The outboard motor according to claim 8 , wherein the communication area has a first area value when the rudder angle has a first rudder angle value, and a second area value smaller than the first area value when the rudder angle has a second rudder angle value larger than the first rudder angle value.
10 . The outboard motor according to claim 8 , wherein
one of the upper coolant channel and the lower coolant channel includes a communication port;
the other of the upper coolant channel and the lower coolant channel includes a plurality of communication ports arranged along a circumferential direction around the steering axis; and
a total area of the plurality of communication ports overlapping the communication port is changeable according to the rudder angle.
11 . The outboard motor according to claim 10 , wherein the plurality of communication ports includes at least two communication ports, and opening areas of the at least two communication ports differ from each other.
12 . The outboard motor according to claim 10 , wherein the plurality of communication ports are located at unequal intervals along the circumferential direction around the steering axis.
13 . The outboard motor according to claim 10 , wherein an opening area communication port is larger than an opening area of the plurality of communication ports.
14 . A boat comprising:
a hull; and
the outboard motor according to claim 8 attached to a rear portion of the hull.