Patent Publication Number: US-2023150633-A1

Title: Electric outboard motor

Description:
TECHNICAL FIELD 
     The present invention relates to an electric outboard motor having an electric motor installed therein as a power source. 
     BACKGROUND ART 
     In recent years, electric outboard motors which are driven by an electric motor are attracting attention as they have little adverse effect on the global environment. In contrast to engine outboard motors, for example, the electric outboard motors discharge no exhaust gas into the water, and therefore, the electric outboard motors can reduce impact on the environment. 
     For example, JP2011-213220A discloses an electric outboard motor in which an electric motor is disposed to be vertically spaced from a gear case that accommodates gears for converting the output of the electric motor into an output in a direction to propel the hull. The electric outboard motor is mounted to the hull via a bracket device, and after the sailing ends, is removed from the hull to be stored in a storage location. In this electric outboard motor, a carrying handle is disposed between the electric motor and the gear case to improve the transportability of the electric outboard motor when the transporter (user) transports the electric outboard motor. The carrying handle is U-shaped and is disposed behind the swivel bracket. Thereby, when transporting the electric outboard motor with the longitudinal direction of the electric outboard motor being horizontal, the use can hold a part near the center of gravity of the electric outboard motor. 
     JP2013-39890A discloses an electric outboard motor in which the carrying handle to be used when transporting the electric outboard motor is fixed to a rear end portion of a lower surface of a lower housing of a driving electric motor and protrudes rearward from the driving electric motor. Namely, in this electric outboard motor, the carrying handle is provided in the vicinity of the driving electric motor which is the heaviest component of the outboard motor main body. The carrying handle has a substantially rectangular annular shape in plan view. 
     However, in the aforementioned conventional technologies, when transporting the electric outboard motor to the storage location or the like, it is necessary to lift the electric outboard motor by grasping the carrying handle with one hand. Therefore, the transport is difficult for a person with a weak grip. 
     SUMMARY OF THE INVENTION 
     In view of the foregoing background, an object of the present invention is to provide an electric outboard motor that can be transported easily even by a person with a weak grip. 
     To achieve the above object, one aspect of the present invention provides an electric outboard motor ( 1 ), comprising: an electric motor ( 8 ) disposed in an upper portion; a propeller ( 12 ) disposed in a lower portion; a drive shaft ( 9 ) extending in an up-down direction to transmit rotation of the electric motor to the propeller; and a case ( 7 ) including a case upper portion ( 19 ) that houses the electric motor and a case lower portion ( 20 ) that houses the drive shaft, wherein the case upper portion includes a rearward extension ( 34 ) that extends rearward relative to the case lower portion, and a shoulder pad member ( 35 ) which is a member separate from the case is provided on a lower surface ( 34   a ) of the rearward extension. 
     According to this aspect, when transporting the electric outboard motor, the user can lift the electric outboard motor by placing the case upper portion on the shoulder such that the shoulder pad member contacts the shoulder. Therefore, even if the user has a weak grip, the user can transport the electric outboard motor easily. 
     Preferably, the shoulder pad member has an elastic modulus smaller than that of the case. 
     According to this aspect, the shoulder hurts less while the user is lifting the electric outboard motor. 
     Preferably, the lower surface of the rearward extension is connected to a rear surface ( 20   a ) of the case lower portion via a curved surface ( 20   b ), and the shoulder pad member is provided to extend from the lower surface to the curved surface. 
     According to this aspect, when the electric outboard motor is swayed while the user is lifting the electric outboard motor, an impact applied from the electric outboard motor to the user is reduced. 
     Preferably, the shoulder pad member extends over a first dimension (D 1 ) in the up-down direction and extends over a second dimension (D 2 ) greater than the first dimension in a front-rear direction. 
     According to this aspect, since the shoulder pad member is longer in the front-rear direction than in the up-down direction, it is easy for the user to carry the electric outboard motor on the shoulder. 
     Preferably, the shoulder pad member extends to a rear end of the rearward extension. 
     According to this aspect, even if the electric outboard motor slides forward while the user is carrying the electric outboard motor on the shoulder, the case upper portion is prevented from being directly placed on the shoulder. Therefore, the user can lift the electric outboard motor stably. 
     Preferably, a grasping member ( 36 ) which is a member separate from the case is provided on a part of the case lower portion spaced downward from the case upper portion. 
     According to this aspect, when transporting the electric outboard motor, the user can grasp the grasping member with a hand. Therefore, the user can lift the electric outboard motor stably. 
     Preferably, the grasping member has an elastic modulus smaller than that of the case. 
     According to this aspect, it is easy for the user to grasp the grasping member. Also, the hand grasping the grasping member does not slip easily. Therefore, the user can lift the electric outboard motor stably. 
     Preferably, the grasping member is made of a sheet material provided along an outer surface of the case lower portion and has a surface formed with irregularities ( 36   a ). 
     According to this aspect, the hand grasping the grasping member does not slip easily. Therefore, the user can lift the electric outboard motor stably. 
     Preferably, the case lower portion has at least one of protruding portions ( 37 ) that protrude in a horizontal direction above and below the grasping member, respectively. 
     According to this aspect, the user can easily recognize the position of the grasping member. Also, if the hand grasping the grasping member slips, the hand is prevented from leaving from the grasping member. 
     Thus, according to an aspect of the present invention, an electric outboard motor that can be transported easily by a person with a weak grip can be provided. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a side view of an electric outboard motor according to an embodiment of the present invention; 
         FIG.  2    is a plan view of the electric outboard motor; 
         FIG.  3    is a side view showing the electric outboard motor in a transport state; and 
         FIG.  4    is a front view showing the electric outboard motor in the transport state. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the following, an embodiment of the present invention will be described in detail with reference to the drawings. In the following embodiment, terms indicating the directions such as front, rear, up, down, etc. are used on the basis of a use state in which an electric outboard motor  1  is mounted to a hull  2 . 
       FIG.  1    is a side view of the electric outboard motor  1  and  FIG.  2    is a plan view of the electric outboard motor  1 . As shown in  FIGS.  1  and  2   , to propel the hull  2  according to an operation by an occupant (operator), the electric outboard motor  1  is detachably mounted to the tail of the hull  2 , specifically, to a transom board  3 . The electric outboard motor  1  is driven by electric power supplied from a battery (not shown in the drawings) installed in the hull  2 . 
     The electric outboard motor  1  includes an outboard motor main body  5  and a mounting device  6  for mounting the outboard motor main body  5  to the hull  2 . The outboard motor main body  5  includes a main body case  7 , an electric motor  8 , a drive shaft  9 , a gear device  10 , a propeller shaft  11 , a propeller  12 , a control device  13 , an input device  14 , and a handle  15 . The mounting device  6  includes a clamp bracket  16 , a tilt mechanism  17 , and a swivel mechanism  18 . In the following, these components of the electric outboard motor  1  will be described. 
     The main body case  7  is made of a metallic material or a rigid resin material to have a predetermined stiffness. The main body case  7  includes a case upper portion  19  disposed in an upper portion and a case lower portion  20  disposed below the case upper portion  19 . The case upper portion  19  and the case lower portion  20  may be made of the same material or may be made of mutually different materials. The case upper portion  19  has a hollow shape that is flat in the up-down direction and elongated in the front-rear direction. The case upper portion  19  houses the electric motor  8  and the control device  13 . The case lower portion  20  has a hollow shape elongated in the up-down direction. The case lower portion  20  houses the drive shaft  9  and the gear device  10 . 
     A lower portion of the case lower portion  20  is integrally provided with a gear case  21  accommodating the gear device  10 , and an anti-ventilation plate  22  is integrally provided above the gear case  21 . The gear case  21  has a bullet shape that is elongated in the front-rear direction and swells laterally relative to the case lower portion  20 . The anti-ventilation plate  22  has a plate shape extending in the horizontal direction and extends out rearward to cover the propeller  12  from above. 
     The electric motor  8  is a power source for rotating the propeller  12  and may be a permanent magnet synchronous motor, for example. The electric motor  8  is disposed in a front portion of the case upper portion  19  such that the output shaft thereof extends vertically downward. In this posture, the electric motor  8  is formed in a flat shape having a horizontal dimension greater than s height dimension. 
     The drive shaft  9  extends in the up-down direction below the electric motor  8 . The upper end portion of the drive shaft  9  is connected to the output shaft of the electric motor  8 . The lower end portion of the drive shaft  9  is integrally provided with a drive gear  23  consisting of a first bevel gear. The drive shaft  9  is rotatably supported by a pair of upper and lower bearings in the case lower portion  20 . 
     The propeller shaft  11  extends in the front-rear direction (horizontal direction) below the drive shaft  9 . Namely, the axial direction of the propeller shaft  11  coincides with the front-rear direction. The front portion of the propeller shaft  11  is accommodated in the gear case  21  and is rotatably supported by a pair of front and rear bearings in the gear case  21 . The front end portion of the propeller shaft  11  is integrally provided with a driven gear  24  consisting of a second bevel gear and meshing with the drive gear  23 . The propeller shaft  11  penetrates through a support hole of the gear case  21  and extends rearward from the gear case  21  to be exposed to the outside of the main body case  7 . 
     The gear device  10  is configured to include the drive gear  23  provided at the lower end of the drive shaft  9  and the driven gear  24  provided at the front end of the propeller shaft  11 . Rotation of the drive shaft  9  is transmitted to the propeller shaft  11  via the gear device  10 . 
     The propeller  12  is fixed to the outer circumference of a rear portion of the propeller shaft  11 . The propeller  12  is positioned more rearward than the rear end portion of the gear case  21  and is exposed to the outside of the main body case  7 . The outer circumferential surface of the propeller  12  is provided with multiple fins  25  radially protruding therefrom. 
     The control device  13  is constituted of a power control unit (PCU). The control device  13  is connected to the battery provided in the hull  2  via a cable  26 . Also, the control device  13  is connected to the input device  14 . According to an operation signal inputted from the input device  14 , the control device  13  supplies electric power to the electric motor  8  and controls the operation of the propeller  12 . 
     The input device  14  is a device for receiving an input operation performed by the occupant and is integrally provided on the case upper portion  19  of the outboard motor main body. In the present embodiment, the input device  14  includes a tiller handle  27  provided on the case upper portion  19  to be pivotable about a laterally extending axis and a throttle grip  28  provided at the free end of the tiller handle  27 . The tiller handle  27  is disposed in a position to protrude forward during operation. When stowed, the tiller handle  27  is pivoted rearward to a position to extend along the case upper portion  19 . 
     When the throttle grip  28  is rotated in one direction, the control device  13  supplies electric power to the electric motor  8  to rotate the propeller  12  in a forward movement direction with a torque corresponding to the amount of rotation. When the throttle grip  28  is rotated in the other direction, the control device  13  supplies electric power to the electric motor  8  to rotate the propeller  12  in a backward movement direction with a torque corresponding to the amount of rotation. 
     The handle  15  is integrally provided on the case upper portion  19  to protrude forward from the front portion of the case upper portion  19 . The handle  15  is provided such that when the electric outboard motor  1  is attached to or detached from the hull  2 , the electric outboard motor  1  can be held stably. The handle  15  has a substantially rectangular annular shape in plan view ( FIG.  2   ). 
     The clamp bracket  16  is a bracket for fixing the outboard motor main body  5  to the hull  2  and rotatably holds a pair of left and right clamp bolts  29  in the front portion thereof. The clamp bracket  16  rotatably supports a laterally extending tilt shaft  30  in a front upper portion thereof and constitutes a part of the tilt mechanism  17 . The electric outboard motor  1  is detachably mounted to the hull  2  by the clamp bracket  16 . 
     The tilt mechanism  17  is a mechanism for rotating the outboard motor main body  5  relative to the clamp bracket  16  with the tilt shaft  30  being a rotational center. The tilt mechanism  17  includes a swivel bracket  31  rotatably supported on the clamp bracket  16  via the tilt shaft  30 . The swivel bracket  31  rotatably holds a swivel shaft  32  that extends in the vertical direction. The electric outboard motor  1  is mounted to the hull  2  to be pivotable up and down about the tilt shaft  30 . 
     The swivel mechanism  18  is a mechanism for rotating the outboard motor main body  5  relative to the swivel bracket  31  with the swivel shaft  32  being a rotational center. The swivel mechanism  18  includes, in addition to the swivel shaft  32 , a pair of upper and lower shaft supports  33  integrally provided on the main body case  7  to support the upper and lower ends of the swivel shaft  32 . The electric outboard motor  1  is mounted to the hull  2  to be pivotable left and right about the swivel shaft  32 . 
     The case upper portion  19  is larger in size than the case lower portion  20  in plan view and protrudes from the upper end of the case lower portion  20  in a radial direction over the entirety in the circumferential direction. An amount of radial protrusion of the case upper portion  19  from the upper end of the case lower portion  20  is the largest in the rear portion. Namely, the case upper portion  19  extends relative to the case lower portion  20  more in the rearward direction than in the other directions. In the following, the part of the case upper portion  19  extending rearward relative to the case lower portion  20  will be referred to as a rearward extension  34 . 
     The upper end portion of the case lower portion  20  diverges in the upward direction and is smoothly connected to the case upper portion  19 . Namely, a rear surface  20   a  of the case lower portion  20  and a lower surface  34   a  of the rearward extension  34  are smoothly connected to each other via the curved surface  20   b.    
     The lower surface  34   a  of the rearward extension  34  of the case upper portion  19  is provided with a shoulder pad member  35  which is a member separate from the case upper portion  19 . The shoulder pad member  35  is made of a material having an elastic modulus smaller than that of the material of the case upper portion  19 . The shoulder pad member  35  may be made of natural rubber, synthetic rubber, silicone rubber, fluorine rubber, urethane rubber or the like, for example. The shoulder pad member  35  is made of a strip-shaped sheet material having a dimension in the front-rear direction longer than a direction in the width dimension, and is joined to the main body case  7  by appropriate joining means such as an adhesive or snap fit. 
     The shoulder pad member  35  is provided to extend from the lower surface  34   a  of the rearward extension  34  to the rear surface  20   a  of the case lower portion  20  via the curved surface  20   b . Also, the shoulder pad member  35  extends from the curved surface  20   b  side to the rear end of the rearward extension  34 . The shoulder pad member  35  also extends in the up-down direction but extends more in the front-rear direction. Namely, the shoulder pad member  35  extends over a first dimension D 1  in the up-down direction and extends over a second dimension D 2  that is greater than the first dimension D 1  in the front-rear direction. 
     At an intermediate portion of the case lower portion  20  in the up-down direction, specifically, at a portion between the swivel mechanism  18  and the anti-ventilation plate  22 , a grasping member  36  which is a member separate from the case lower portion  20  is provided. The grasping member  36  is made of a material having an elastic modulus smaller than that of the material of the case lower portion  20 . The grasping member  36  may be made of natural rubber, synthetic rubber, silicone rubber, fluorine rubber, urethane rubber or the like, for example. 
     The case lower portion  20  has an elliptical, flat cross-sectional shape. The grasping member  36  is made of a sheet material and is provided to be in an arc shape convex forward and to cover a front portion of the case lower portion  20 . In another embodiment, the grasping member  36  may be provided to cover a rear portion of the case lower portion  20  or to cover the entire circumference of the case lower portion  20 . A surface (an outer surface with an arc-shaped cross section) of the grasping member  36  has irregularities  36   a  formed thereon. The grasping member  36  is joined to the main body case  7  by appropriate joining means such as an adhesive or snap fit. 
     The grasping member  36  is disposed in a position spaced from the swivel mechanism  18  and the anti-ventilation plate  22 . At parts of the case lower portion  20  above and below the grasping member  36 , specifically, at the part between the grasping member  36  and the swivel mechanism  18  and at the part between the grasping member  36  and the anti-ventilation plate  22 , arc-shaped protruding portions  37  that protrude forward are integrally formed. 
     The electric outboard motor  1  is configured as described above. Next, a mode of transport of the electric outboard motor  1  will be described with reference to  FIGS.  3  and  4   . 
       FIGS.  3  and  4    are a side view and a front view, respectively, showing the electric outboard motor  1  in the transport state. As shown in  FIGS.  3  and  4   , the electric outboard motor  1  may be detached from the hull  2  after the sailing ends, and then, may be transported to the storage location to be stored in the storage location. The electric outboard motor  1  stored in the storage location is transported to be mounted to the hull  2  when the sailing starts. 
     As described above, the case upper portion  19  has the rearward extension  34 . Therefore, as shown in  FIG.  3  or  4   , when transporting the electric outboard motor  1 , the user can place the rearward extension  34  on the shoulder such that the case lower portion  20  is positioned in front of the body of the user. Preferably, the user grasps the grasping member  36  and makes the case lower portion  20  contact the front side of the body. By lifting the electric outboard motor  1  in this way, the user does not have to support the load of the electric outboard motor  1  with hands. In other words, the muscle strength of the arms and hands required for transport of the electric outboard motor  1  is reduced. Therefore, a person with a weak grip can transport the electric outboard motor  1  easily, and the transportability of the electric outboard motor  1  is improved. 
     Note that, as shown in  FIG.  3   , the electric outboard motor  1  may be lifted and transported in a posture in which the case lower portion  20  extends vertically, namely, the propeller  12  is positioned below the shoulder on which the case upper portion  19  is placed. Alternatively, as shown in  FIG.  4   , the electric outboard motor  1  may be lifted and transported in a posture in which the case lower portion  20  extends diagonally in front of the body of the user, namely, the propeller  12  is placed below the shoulder on the side opposite from the shoulder on which the case upper portion  19  is placed. 
     Next, operations and effects of the electric outboard motor  1  according to the embodiment will be described. 
     As shown in  FIG.  1   , in the present embodiment, the shoulder pad member  35 , which is a member separate from the main body case  7  is provided on the lower surface  34   a  of the rearward extension  34  of the case upper portion  19 . Thereby, when transporting the electric outboard motor  1 , the user can lift the electric outboard motor  1  by placing the case upper portion  19  on the shoulder such that the shoulder pad member  35  contacts the shoulder. Therefore, even if the user has a weak grip, the user can transport the electric outboard motor  1  easily. 
     Since the shoulder pad member  35  has an elastic modulus smaller than that of the case upper portion  19 , the shoulder hurts less while the user is lifting the electric outboard motor  1 . 
     The rear surface  20   a  of the case lower portion  20  and the lower surface  34   a  of the rearward extension  34  are connected to each other via the curved surface  20   b , and the shoulder pad member  35  is provided to extend from the lower surface  34   a  of the rearward extension  34  to the curved surface  20   b . Therefore, when the electric outboard motor  1  is swayed while the user is lifting the electric outboard motor  1 , an impact applied from the electric outboard motor  1  to the user is reduced. 
     The shoulder pad member  35  extends over a first dimension D 1  in the up-down direction and extends over a second dimension D 2  that is greater than the first dimension D 1  in the front-rear direction. Namely, the shoulder pad member  35  is longer in the front-rear direction than in the up-down direction. Therefore, it is easy for the user to carry the electric outboard motor  1  on the shoulder. 
     The shoulder pad member  35  extends to the rear end of the rearward extension  34 . Thereby, even if the electric outboard motor  1  slides forward while the user is carrying the electric outboard motor  1  on the shoulder, the case upper portion  19  is prevented from being directly placed on the shoulder. Therefore, the user can lift the electric outboard motor  1  stably. 
     The grasping member  36 , which is a member separate from the main body case  7 , is provided on a part of the case lower portion  20  spaced downward from the case upper portion  19 . Thereby, when transporting the electric outboard motor  1 , the user can grasp the grasping member  36  with a hand. Therefore, the user can lift the electric outboard motor  1  stably. 
     The grasping member  36  has an elastic modulus smaller than that of the case lower portion  20 . Thereby, it is easy for the user to grasp the grasping member  36 . Also, the hand grasping the grasping member  36  does not slip easily. Therefore, the user can lift the electric outboard motor  1  stably. 
     The grasping member  36  is made of a sheet material provided along the outer surface of the case lower portion  20  and has a surface formed with irregularities  36   a . Thereby, the hand grasping the grasping member  36  does not slip easily. Therefore, the user can lift the electric outboard motor  1  stably. 
     The case lower portion  20  has at least one of the protruding portions  37  that protrude in the horizontal direction above and below the grasping member  36 . Thereby, the user can easily recognize the position of the grasping member  36 . Also, if the hand grasping the grasping member  36  slips, the hand is prevented from leaving from the grasping member  36 . 
     A concrete embodiment of the present invention has been described in the foregoing, but the present invention is not limited to the above embodiment and may be modified or altered in various ways. For example, in the above embodiment, the case upper portion  19  houses the electric motor  8  and the control device  13  but the control device  13  may be provided outside the outboard motor main body  5 . The shoulder pad member  35  and the grasping member  36  are only required to be members separate from the main body case  7  and may be made of the same material as the material of the main body case  7 . Besides, the concrete structure, arrangement, number, material, angle, etc. of each member or part described in the above embodiment may be appropriately changed without departing from the spirit of the present invention. Also, not all of the components shown in the foregoing embodiment are necessarily indispensable and they may be selectively adopted as appropriate.