Electric outboard motor

Abstract

An electric outboard motor includes a screw, an electric motor, an outboard motor case, and a cooling portion. The outboard motor case accommodates the electric motor. The cooling portion cools a heat generation portion at an inside or an outside of the outboard motor case by a cooling liquid. At least a lower region of the outboard motor case that is submerged in outside water is constituted of a multiple case structure body that includes an outer case and an inner case. In the multiple case structure body of the lower region, at least part of a space portion that is surrounded by the outer case and the inner case is a cooling liquid passage through which the cooling liquid supplied to the cooling portion flows.

1 . An electric outboard motor comprising:
 a screw that is submerged in outside water and generates a propulsion force;   an electric motor that drives the screw;   an outboard motor case that accommodates the electric motor; and   a cooling portion that cools a heat generation portion at an inside or an outside of the outboard motor case by a cooling liquid,   wherein at least a lower region of the outboard motor case that is submerged in the outside water is constituted of a multiple case structure body that includes an outer case and an inner case,   a power transmission mechanism that transmits a drive force of the electric motor to the screw is accommodated inside the inner case of the lower region, and   in the multiple case structure body of the lower region, at least part of a space portion that is surrounded by the outer case and the inner case is a cooling liquid passage through which the cooling liquid supplied to the cooling portion flows.   
     
     
         2 . The electric outboard motor according to  claim 1 ,
 wherein the outer case has an inner surface that is in contact with the cooling liquid in the cooling liquid passage and is a heat exchange portion that performs heat exchange between the outside water and the cooling liquid in the cooling liquid passage.   
     
     
         3 . The electric outboard motor according to  claim 2 ,
 wherein the space portion of the multiple case structure body is partitioned by a partition wall, and the cooling liquid passage is formed.   
     
     
         4 . The electric outboard motor according to  claim 3 ,
 wherein the cooling liquid passage is constituted of part of the space portion partitioned by the partition wall.   
     
     
         5 . The electric outboard motor according to  claim 1 ,
 wherein a piping that forms the cooling liquid passage is arranged in the space portion of the multiple case structure body.   
     
     
         6 . The electric outboard motor according to  claim 1 ,
 wherein in the outboard motor case, the lower region and a motor accommodation portion that continues to the lower region are constituted of the multiple case structure body.   
     
     
         7 . The electric outboard motor according to  claim 6 ,
 wherein a cooling liquid supply port that supplies the cooling liquid which has flowed through the multiple case structure body of the lower region to the heat generation portion of the electric motor is provided on a wall of the inner case of the motor accommodation portion.   
     
     
         8 . The electric outboard motor according to  claim 7 ,
 wherein a cooling liquid storage portion that stores the cooling liquid which has cooled the electric motor and a pump device that supplies the cooling liquid stored in the cooling liquid storage portion to the multiple case structure body of the lower region are arranged in the motor accommodation portion.   
     
     
         9 . (canceled) 
     
     
         10 . The electric outboard motor according to  claim 1 ,
 wherein the cooling liquid in the cooling liquid passage flows from a rearward side in a propulsion direction of the lower region of the outboard motor case through a forward side toward the cooling portion.