Patent Publication Number: US-2022234706-A1

Title: Outboard motor, marine vessel, and marine propulsion device

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of Japanese Patent Application No. 2021-008737, filed Jan. 22, 2021, which is hereby incorporated by reference herein in its entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an outboard motor, a marine vessel including a lower case and an upper case, and a marine propulsion device. 
     2. Description of the Related Art 
     In the related art, as shown in  FIGS. 8A to 8C , an outboard motor  80  includes a lower case  82  having a propeller  81  as a propulsor, and an upper case  83  having a drive shaft that transmits a driving force of an engine as a drive source to the propeller (see, for example, Japanese Laid-open Patent Publication (Kokai) No. 2020-29186). The lower case  82  and the upper case  83  are manufactured via die-casting aluminum, the lower case  82  being attached to the upper case  83  so that a mating surface  82   a  of the lower case  82  is connected to a mating surface  83   a  of the upper case  83 . 
     Since the lower case  82  sinks under a water surface when a marine vessel sails, the lower case  82  significantly affects the sailing performance of the marine vessel. In recent years, the use of the marine vessel has been diversified, and the sailing performance required for the marine vessel has also been diversified, and various types of lower cases corresponding to the sailing performance are manufactured. The lower case is changed (modified) in design in accordance with the required sailing performance, and the changed lower case is attached to the upper case  83 . 
     When the lower case is changed, the shapes of the lower case before and after the change may be different. For example, in the case of a lower case having high-durability, the high-durability lower case  84  is increased in size in order to accommodate drive components having a lifespan twice or more than that of a typical lower case  82  based on the assumption that it will be used for a longer period of time than the typical lower case  82  ( FIG. 8B ). In the case of a high-speed lower case, a high-speed lower case  85  is designed by being miniaturized so as to be smaller than the typical lower case  82  in order to reduce resistance ( FIG. 8C ). That is, the high-durability lower case  84  and the high-speed lower case  85  are each different in shape from the typical lower case  82 . 
     Accordingly, as shown in  FIGS. 8B and 8C , the mating surface  83   a  of the upper case  83  does not match a mating surface  84   a  of the lower case  84  or a mating surface  85   a  of the lower case  85 , and which may be difficult to attach the high-durability lower case  84  or the high-speed lower case  85  to the upper case  83 . 
     In this case, it is necessary to separately manufacture a new and different upper case having a mating surface matching the mating surface  84   a  of the high-durability lower case  84  or the mating surface  85   a  of the high-speed lower case  85 . Therefore, there is room for improvement from the viewpoint of reducing the number of components and shortening a development period of the outboard motor. 
     SUMMARY OF THE INVENTION 
     Preferred embodiments of the present invention significantly reduce or prevent an increase in the number of types of upper cases. 
     According to a preferred embodiment of the present invention, an outboard motor for attachment to a hull of a marine vessel includes a lower case including a propeller shaft to rotate a propeller, an upper case including a drive shaft to transmit a power to the propeller shaft, and an intermediate structure connecting the lower case and the upper case, wherein the lower case is selected from among a plurality of different lower cases, and the intermediate structure is configured to connect any of the plurality different lower cases to the upper case. 
     According to this structural configuration, the intermediate structure connects the upper case and the lower case so as to make it possible to attach, by using the intermediate structure connectable to mating surfaces of many different lower cases with different shapes or sizes, any of the different lower cases to the same upper case, thus eliminating the need to manufacture and provide different upper cases. As a result, it is possible to significantly reduce or prevent the increase in the number of types of upper cases. 
     The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an external view schematically illustrating an outboard motor according to a preferred embodiment of the present invention. 
         FIGS. 2A and 2B  are diagrams for describing attachments corresponding to various lower cases. 
         FIGS. 3A and 3B  are diagrams for describing a mechanism to transmit a propulsive force of a propeller to a hull of a marine vessel. 
         FIGS. 4A and 4B  are external views schematically illustrating an outboard motor according to a first variation of a preferred embodiment of the present invention. 
         FIGS. 5A and 5B  are external views schematically illustrating an outboard motor according to a second variation of a preferred embodiment of the present invention. 
         FIGS. 6A and 6B  are external perspective views schematically illustrating an attachment of an outboard motor according to a third variation of a preferred embodiment of the present invention. 
         FIGS. 7A and 7B  are diagrams for describing sacrificial anodes according to preferred embodiments of the present invention and variations thereof. 
         FIGS. 8A to 8C  are diagrams for describing a problem associated with a change of a lower case in an outboard motor of the related art. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. 
       FIG. 1  is an external view schematically illustrating an outboard motor according to a preferred embodiment of the present invention. Referring to  FIG. 1 , an outboard motor  10  includes, as a casing enclosing various components, a cowl  11 , a standard lower case  12 , an upper case  13 , and an attachment  14  (intermediate structure). The cowl  11  encloses an engine (not illustrated) as a drive source, and the standard lower case  12  includes a propeller  15  as a propulsor and encloses a propeller shaft  40  (propeller shaft) to rotate the propeller  15 . The upper case  13  encloses a drive shaft  27  to transmit a driving force (power) of the engine to the propeller shaft  40 . 
     In addition, the outboard motor  10  includes a suspension mechanism  16  to attach the outboard motor  10  to a stern (not illustrated) of a hull of the marine vessel, and the suspension mechanism  16  also defines and functions as a steering mechanism and a lifting mechanism of the outboard motor  10  to tilt up the outboard motor  10  when the marine vessel is stored. 
     The attachment  14  is interposed between the standard lower case  12  and the upper case  13  to connect the standard lower case  12  and the upper case  13 . A shape of an upper mating surface  14   a  of the attachment  14  matches a mating surface  13   a  of the upper case  13 , and a shape of a lower mating surface  14   b  of the attachment  14  matches a mating surface  12   a  of the standard lower case  12 . 
     In the outboard motor  10 , as illustrated in  FIGS. 2A and 2B , in some cases a high-durability lower case  17  or a high-speed lower case  19  is attached instead of the standard lower case  12 . However, since the high-durability lower case  17  and the high-speed lower case  19  are different in shape from the standard lower case  12 , neither a mating surface  17   a  of the high-durability lower case  17  nor a mating surface  19   a  of the high-speed lower case  19  matches the lower mating surface  14   b  of the attachment  14 . 
     On the other hand, in the present preferred embodiment, an attachment  18  ( FIG. 2A ) having a lower mating surface  18   b  matching the mating surface  17   a  of the high-durability lower case  17  is used. An upper mating surface  18   a  of the attachment  18  has the same shape as the upper mating surface  14   a  of the attachment  14 . Accordingly, the attachment  18  is able to attach to the high-durability lower case  17  and to the upper case  13 , and thus is able to connect the upper case  13  and the high-durability lower case  17 . 
     In the present preferred embodiment, an attachment  20  ( FIG. 2B ) having a lower mating surface  20   b  matching the mating surface  19   a  of the high-speed lower case  19  is used. An upper mating surface  20   a  of the attachment  20  has the same shape as the upper mating surface  14   a  of the attachment  14 . Accordingly, the attachment  20  is able to attach to the high-speed lower case  19  and to the upper case  13 , and thus is able to connect the upper case  13  and the high-speed lower case  19 . 
     Further, for example, as illustrated in  FIG. 3A , the upper case  13  includes a frame body  21  and a resin cover  38  that covers the frame body  21 . The frame body  21  is made of metal, for example, aluminum, and is fastened to the attachment  14  and the suspension mechanism  16 . A propulsive force generated by the propeller  15  is transmitted to the hull via the standard lower case  12 , the attachment  14 , the frame body  21 , and the suspension mechanism  16 . Instead of the frame body  21  and the cover  38 , for example and as illustrated in  FIG. 3B , the upper case  13  may include a main body  39  in the shape of a case and having a rigid body made of metal, for example, aluminum, and a cover (not illustrated) that improves an appearance of the main body  39 , and the main body  39  may be fastened to the attachment  14  and the suspension mechanism  16 . In this case, instead of the frame body  21 , the main body  39  transmits the propulsive force generated by the propeller  15  to the hull. 
     According to the present preferred embodiment, since the attachment  14  connects the upper case  13  and the standard lower case  12 , when the high-durability lower case  17  or the high-speed lower case  19  are attached to the upper case  13 , provided that the attachment  18  connectable to the mating surface  17   a  of the high-durability lower case  17  or the attachment  20  connectable to the mating surface  19   a  of the high-speed lower case  19  is used instead of the attachment  14 , the high-durability lower case  17  or the high-speed lower case  19  is able to be attached to the upper case  13 . Accordingly, it is possible to eliminate the need to separately manufacture a different, additional upper case  13  when the high-durability lower case  17  or the high-speed lower case  19  is desired, and it is possible to significantly reduce or prevent an increase in the number of types of the upper case  13 . 
     In addition, in the present preferred embodiment, since the outboard motor  10  has the frame body  21  or the main body  39  made of a rigid body, which is fastened to the attachment  14  and the suspension mechanism  16 , the propulsive force generated by the propeller  15  is reliably transmitted to the hull via the attachment  14  and the suspension mechanism  16 . 
     Typically, the lower case encloses a gearbox that engages with the drive shaft to transmit the rotation of the drive shaft to the propeller shaft, and a link mechanism that switches rotation directions of the propeller. A shift rod is connected to the link mechanism, and the shift rod is parallel or substantially parallel to the drive shaft and is rotated or moved up and down by a shift actuator. The link mechanism moves a dog clutch in the gearbox via a shift slider in accordance with the movement of the shift rod, and thus the link mechanism switches the rotation directions of the propeller. The link mechanism, the shift rod, and the shift actuator define a shift mechanism. 
     In the related art, although a shift actuator is enclosed in an upper case or a cowl, a distance between a link mechanism and a gearbox may vary in accordance with the type of a lower case, and thus, a relative position (pitch) of a shift rod with respect to a drive shaft may change. As a result, when the lower case is changed and attached, it may be necessary to separately manufacture a different and additional upper case in order to change the pitch between the shift rod and the drive shaft by changing the position of the shift actuator. 
     On the other hand, in a first variation of a preferred embodiment of the present invention, the shift actuator is located in the attachment.  FIGS. 4A and 4B  are external views schematically illustrating an outboard motor according to the first variation. For example, there are some cases in which a distance between the enclosed link mechanism  22  and gearbox  23  is different between the standard lower case  12  and the high-durability lower case  17 . The present variation presents attachments  24  and  25  respectively corresponding to the standard lower case  12  and the high-durability lower case  17 . A shape of an upper mating surface  24   a  of the attachment  24  is the same as a shape of an upper mating surface  25   a  of the attachment  25 . 
     In the attachment  24 , a position of a shift actuator  28  is set such that a pitch between a shift rod  26  and a drive shaft  27  (drive shaft) corresponds to a distance between the link mechanism  22  and the gearbox  23  in the standard lower case ( FIG. 4A ). Similarly, in the attachment  25 , a position of the shift actuator  28  is set such that a pitch between the shift rod  26  and the drive shaft  27  corresponds to a distance between the link mechanism  22  and the gearbox  23  in the high-durability lower case  17  ( FIG. 4B ). It should be noted that when the distance between the link mechanism  22  and the gearbox  23  enclosed in the high-speed lower case  19  is different from the distance between the link mechanism  22  and the gearbox  23  enclosed in the standard lower case  12  or the high-durability lower case  17 , an attachment in which the position of the shift actuator  28  is set such that the pitch between the shift rod  26  and the drive shaft  27  corresponds to the distance between the link mechanism  22  and the gearbox  23  in the high-speed lower case  19  is used. 
     Accordingly, even though the distance between the link mechanism and the gearbox is different among different the different types of lower cases, the differently shaped or sized lower case is able to be attached to the same upper case by replacing the attachment. That is, it is possible to eliminate the need to manufacture and provide different upper cases  13 , and to significantly reduce or prevent an increase in the number of types of the upper case  13 . 
     It should be noted that, although a plurality of types of attachments in which the position of the shift actuator  28  is changed in accordance with the type of the lower case is used in the present variation, in a case in which the shape of the mating surfaces of the various lower cases is not changed, the shift actuator  28  may be movable in the attachment so that the position of the shift actuator  28  is changed in accordance with the distance between the link mechanism  22  and the gearbox  23  in each lower case. In this case, it is possible to eliminate the need to manufacture and provide differently shaped or sized attachments, which significantly reduces or prevents an increase in the number of types of attachments. 
     In addition, in recent years it has been studied in outboard motors to drive the propeller not only by an internal combustion engine but also by an electric motor. For example, a hybrid outboard motor including an engine and an electric motor is disclosed in Japanese Laid-open Patent Publication (Kokai) No. 2020-29186. 
     The lower case in the hybrid outboard motor encloses a motor gearbox to transmit a driving force of the electric motor to the propeller shaft in addition to the link mechanism and the gearbox which engages with the drive shaft to transmit the driving force of the engine. The electric motor is located in the lower case in the hybrid outboard motor described in Japanese Laid-open Patent Publication (Kokai) No. 2020-29186. However, since the shape of the lower case greatly affects the sailing performance of the marine vessel, an electric motor that affects the shape of the lower case is preferably located in the upper case. Therefore, when the outboard motor is a hybrid, it may be necessary to manufacture not only the lower case but also the upper case and locate the electric motor in the upper case. 
     Regarding this matter, in a second variation of a preferred embodiment of the present invention, the electric motor is located in the attachment.  FIGS. 5A and 5B  are external views schematically illustrating an outboard motor according to the second variation of a preferred embodiment of the present invention. 
     In the outboard motor  10  which is not a hybrid and in which the propeller  15  is driven only by an engine as described above, the standard lower case  12  encloses the link mechanism  22  and the gearbox  23  but does not enclose a gearbox for a motor ( FIG. 5A ). On the other hand, in a hybrid outboard motor  29 , a hybrid-compatible lower case  30  encloses not only a link mechanism  22  and a gearbox  23  but also a gearbox for a motor (a motor gearbox  31 ) ( FIG. 5B ). In this case, a hybrid-compatible attachment  32  encloses an electric motor  33 , and the electric motor  33  is connected to the motor gearbox  31  via a motor drive shaft  34 . With this configuration, in the hybrid outboard motor  29  including the hybrid-compatible attachment  32 , a propeller  15  is driven by an engine or the electric motor  33 . A shape of an upper mating surface  32   a  of the hybrid-compatible attachment  32  is the same as a shape of an upper mating surface  24   a  of the attachment  24 . In the hybrid-compatible attachment  32 , the electric motor  33  is located so as to face the motor gearbox  31 . 
     Accordingly, when the standard lower case  12  is replaced with the hybrid-compatible lower case  30  in order to provide a hybrid the outboard motor, the hybrid-compatible lower case  30  is able to be attached to the upper case  13  only by replacing the attachment  24  with the hybrid-compatible attachment  32 . Accordingly, it is possible to eliminate the need to separately manufacture a different upper case  13  in order to hybridize the outboard motor, and it is possible to prevent an increase in the number of types of the upper cases  13 . 
     In addition, the electric motor  33  is enclosed in the hybrid-compatible attachment  32 , and thus, it is possible to eliminate the need to locate the electric motor  33  in the hybrid-compatible lower case  30 , which makes it possible to prevent the shape of the hybrid-compatible lower case  30  from being hydrodynamically disadvantageous. As a result, even though the outboard motor is a hybrid, it is possible to reduce or prevent a significant influence on the sailing performance of the marine vessel. 
     Instead of the hybrid-compatible lower case  30 , a high-durability hybrid-compatible lower case or a high-speed hybrid-compatible lower case may be used. In this case, the relative position of the motor gearbox  31  with respect to the link mechanism  22  and the gearbox  23  may change. Regarding this matter, the electric motor  33  may be movable in the hybrid-compatible attachment  32  so that the position of the electric motor  33  may be changed in accordance with the relative position of the motor gearbox  31  with respect to the link mechanism  22  and the gearbox  23  in each lower case. Alternatively, a plurality of hybrid-compatible attachments in which the electric motor  33  is provided at the position corresponding to the relative position of the motor gearbox  31  with respect to the link mechanism  22  and the gearbox  23  in each lower case may be prepared, and the hybrid-compatible attachment corresponding to each lower case may be used. 
     In the outboard motor, since at least a portion of the lower case is submerged and causes splashes while the marine vessel sails, a splash plate (anti-splash plate) to prevent the splashes from scattering may be conventionally provided on the upper case. 
     The scattering of the splashes changes in accordance with the shape of the lower case. Thus, for example, when the standard lower case  12  is replaced with the high-durability lower case  17  or the high-speed lower case  19 , it may be necessary to change the shape of the splash plate in accordance with the scattering of the splashes in each case, and it may be conventionally necessary to separately manufacture and provide additional different upper cases. 
     In contrast to the conventional location of the splash plate, in a third variation of a preferred embodiment of the present invention, a splash plate is provided on the attachment.  FIGS. 6A and 6B  are external perspective views schematically illustrating an attachment of an outboard motor according to the third variation of a preferred embodiment of the present invention. 
     In the present variation, for example, a splash plate  35  is provided at an upper portion of an attachment  14  attached to a standard lower case  12  ( FIG. 6A ), and a splash plate  36  is provided at an upper portion of an attachment  20  attached to a high-speed lower case  19  ( FIG. 6B ). The splash plate  35  and the splash plate  36  have different shapes. Specifically, since the amount of splashes increases when the high-speed lower case  19  is used, the splash plate  36  is larger than the splash plate  35 . The splash plate may also be provided at an upper portion of an attachment  18  attached to a high-durability lower case  17 , wherein a shape of this splash plate is also different from shapes of the splash plates  35  and  36 . 
     Accordingly, even in a case in which the lower case is replaced and the scattering of the splashes changes, the splash plate suitable for the changed scattering of the splashes is able to be used by replacing the attachment. That is, it is possible to eliminate the need to replace the upper case in order to change the shape of the splash plate, and thus, it is possible to eliminate the need to separately manufacture and provide additional differently shaped or sized upper cases  13 . 
     Each splash plate may be integral with each attachment, or may be separable with respect to each attachment. In a case where each splash plate is separable with respect to each attachment, provided that the shapes of the mating surfaces of the lower cases are the same, the scattering of the splashes is reduced by replacing only the splash plate without changing the attachment in accordance with the change of the lower case. Accordingly, it is possible to save time and effort when replacing the attachment. 
     Conventionally, in order to reduce the progress of corrosion of each part of the outboard motor  10 , a sacrificial anode is provided in the suspension mechanism and the lower case. Regarding this matter, in the above-described preferred embodiments/variations, a sacrificial anode  37  is provided in the attachment  14 . Specifically, in the attachment  14 , the sacrificial anode  37  is provided at a position ( FIG. 7A ) at which waves or splashes are applied while the marine vessel sails, or a position ( FIG. 7B ) of the marine vessel that is below the water surface even when the outboard motor  10  is tilted up during storage of the marine vessel. With this structural configuration, the sacrificial anode  37  is reliably brought into contact with the water, and thus, the progress of the corrosion of each part of the outboard motor  10  is reduced. 
     While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims. 
     For example, although preferred embodiments of the present invention are applied to an outboard motor in the above-described preferred embodiments, the present invention may be applied to an inboard/outboard motor including an upper case and a lower case. Likewise in this case, an inboard/outboard motor includes an attachment, and the attachment connects the lower case and the upper case.