Outboard motor

Abstract

An outboard motor includes a cooling device which includes a supply passage supplying a cooling water taken into a lower unit to a cooling mechanism. A first shaft portion of the connecting mechanism has a cylindrical shape, is provided in an upper part of the lower unit, and has an axis coaxial with the axis of a drive shaft. A second shaft portion has a cylindrical shape, is provided in a lower part of an upper unit, and has an axis coaxial with the axis of the drive shaft. One shaft portion of the first and the second shaft portions is inserted into the other shaft portion to be pivotable relative to the other shaft portion. The drive shaft is inserted into the one shaft portion with a space. A part of the supply passage is formed of the space between the drive shaft and the one shaft portion.

What is claimed is: 
     
         1 . An outboard motor comprising:
 an upper unit including a drive motor;   a lower unit including a propeller shaft;   a drive shaft configured to transmit a rotation of the drive motor to the propeller shaft;   a connecting mechanism connecting the lower unit to the upper unit to be pivotable about an axis of the drive shaft; and   a cooling device, wherein   the cooling device includes
 a cooling mechanism provided in the upper unit and configured to cool an equipment requiring cooling including the drive motor by using cooling water, 
 an intake port configured to take water outside the outboard motor into the lower unit as cooling water, and 
 a supply passage provided from the lower unit to the upper unit and configured to supply the cooling water taken into the lower unit to the cooling mechanism, 
   the connecting mechanism includes
 a first shaft portion having a cylindrical shape, provided in an upper part of the lower unit, and having an axis coaxial with the axis of the drive shaft, and 
 a second shaft portion having a cylindrical shape, provided in a lower part of the upper unit, and having an axis coaxial with the axis of the drive shaft, and 
   one shaft portion of the first shaft portion and the second shaft portion is inserted into the other shaft portion to be pivotable relative to the other shaft portion,   the drive shaft is inserted into the one shaft portion with a space, and   a part of the supply passage is formed of the space between the drive shaft and the one shaft portion.   
     
     
         2 . The outboard motor according to  claim 1 , wherein
 the one shaft portion is the first shaft portion,   the supply passage includes
 a lower supply passage provided in the lower unit and connecting the intake port to the space, 
 the space, 
 an upper supply passage provided in the upper unit and having one end side connected to the cooling mechanism, and 
 a communication passage communicating between the space and the other end side of the upper supply passage, and 
   a communication passage forming member forming the communication passage is provided at an upper opening portion of the first shaft portion.   
     
     
         3 . The outboard motor according to  claim 2 , wherein
 the communication passage forming member includes
 a lid portion attached to the upper opening portion of the first shaft portion, 
 a tubular portion extending upward from an outer periphery of the lid portion and covering an opening portion on the other end side of the upper supply passage, 
 a shaft insertion hole provided in a center portion of the lid portion and into which the drive shaft is inserted, and 
 a communication hole provided in an inner periphery of the lid portion and communicating between the space and inside of the tubular portion. 
   
     
     
         4 . The outboard motor according to  claim 3 , wherein
 the tubular portion is fixed to the upper unit, and   the lid portion is inserted into the first shaft portion to be pivotable relative to the first shaft portion.   
     
     
         5 . The outboard motor according to  claim 4 , wherein a sealing member is provided between an outer periphery of the lid portion and an inner periphery of the first shaft portion. 
     
     
         6 . The outboard motor according to  claim 1 , wherein
 the cooling device includes a water pump configured to send the cooling water taken into the lower unit to the cooling mechanism, and   the water pump is disposed on a lower end side of the first shaft portion.   
     
     
         7 . The outboard motor according to  claim 1 , wherein
 the cooling device includes a water pump configured to send the cooling water taken into the lower unit to the cooling mechanism,   the water pump is a rotary variable displacement water pump including an impeller made of rubber,   the impeller is fixed to the drive shaft and configured to rotate integrally with the drive shaft.   
     
     
         8 . The outboard motor according to  claim 1 , wherein
 the cooling device includes a drain port configured to discharge the cooling water after flowing in the cooling mechanism to outside of the outboard motor,   the drain port is provided in the lower part of the upper unit behind the second shaft portion.