OUTBOARD MOTOR AND WATERCRAFT

An outboard motor includes a body case, a drive source, a propeller, a drive shaft, a bracket attachable to a hull, a steering support including a steering shaft including a first end and a second end to rotatably support the body case about the steering shaft with respect to a bracket, and a steering located at the first end of the steering shaft to output a steering force to rotate the body case. The steering shaft is tilted with respect to the drive shaft such that a distance from the first end to the drive shaft differs from a distance from the second end to the drive shaft. When viewed in an up-down direction, the steering is located on an opposite side of the first end of the steering shaft from the second end of the steering shaft.

Skip to: Description  ·  Claims  · Patent History  ·  Patent History
Description
CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to Japanese Patent Application No. 2025-005871 filed on Jan. 16, 2025. The entire contents of this application are hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

    • The technologies and example embodiments disclosed herein relate to outboard motors and watercraft.

2. Description of the Related Art

A watercraft includes a hull and an outboard motor attached to a rear portion of the hull. The outboard motor generates a propulsive force to propel the watercraft.

The outboard motor includes a body case, a drive source, a propeller, a drive shaft, and a bracket. The drive source has an output shaft and is accommodated in an upper portion of the body case. The propeller is rotatably mounted at a lower portion of the body case. The drive shaft is provided in the body case in a manner to extend in an up-down direction. A first end of the drive shaft is coupled to the output shaft of the drive source to transmit torque, and a second end of the drive shaft is coupled to the propeller to transmit the torque. The bracket is attached to the hull. The bracket includes a steering shaft, and supports the body case to be rotatable about the steering shaft.

Outboard motors are not limited to outboard motors having a configuration in which the steering shaft is parallel to the drive shaft, and outboard motors having a configuration that the steering shaft is tilted with respect to the drive shaft have been known (for example, see JP S62-184998 A, JP H03-139496 A, and U.S. Pat. No. 9,776,699).

There is a case where the outboard motor is provided with a steering actuator that outputs a steering force for causing the body case to rotate about the steering shaft. In a conventional outboard motor, the relationship between the steering shaft and the steering actuator has not been studied sufficiently in the configuration that the steering shaft is tilted with respect to the drive shaft, and there is room for improvement. Such a problem is not limited to the steering actuator, but is common to an outboard motor that includes a manual steering.

SUMMARY OF THE INVENTION

Example embodiments of the present invention disclose technologies capable of solving the above-described problems.

The technologies disclosed herein can be implemented as the following example embodiments.

An outboard motor according to an example embodiment of the present invention includes a body case, a drive source in the body case and including an output shaft a propeller rotatably mounted to the body case, a drive shaft in the body case and including a first end coupled to the output shaft of the drive source and a second end coupled to the propeller, a bracket attachable to a hull, a steering support including a steering shaft including a first end and a second end to rotatably support the body case by the bracket about the steering shaft, and a steering at the first end of the steering shaft to output a steering force to cause the body case to rotate, wherein the steering shaft is tilted with respect to the drive shaft such that a distance from the first end of the steering shaft to the drive shaft and a distance from the second end of the steering shaft to the drive shaft differ from each other, and the steering is located on an opposite side of the first end of the steering shaft from the second end of the steering shaft portion when viewed in an up-down direction.

An outboard motor according to another example embodiment of the present invention includes a body case, a drive source in the body case and including an output shaft, a propeller rotatably mounted to the body case, a drive shaft in the body case and including a first end coupled to the output shaft and a second end coupled to the propeller, a steering support including a steering shaft including a first end and a second end to rotatably support the body case about the steering shaft, and a steering at the first end of the steering shaft to output a steering force to cause the body case to rotate, wherein the steering shaft is tilted with respect to the drive shaft such that a distance from the first end of the steering shaft to the drive shaft and a distance from the second end of the steering shaft to the drive shaft differ from each other, and the steering is closer to the second end of the steering shaft than to the first end of the steering shaft when viewed in an up-down direction.

The technologies disclosed herein can be implemented in various example embodiments, and can be implemented as outboard motors, watercraft including the outboard motors and hulls, and the like, for example.

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 example embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view schematically illustrating a configuration of a watercraft according to an example embodiment of the present invention.

FIG. 2 is a side view schematically illustrating a configuration of an outboard motor.

FIG. 3 is a side view schematically illustrating a configuration of a portion of the outboard motor.

FIG. 4 is a view illustrating a relationship between a steering shaft of an outboard motor and steering torque in a comparative example.

FIG. 5 is a view illustrating a relationship between a steering shaft of the outboard motor and the steering torque according to an example embodiment of the present invention.

 DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS

FIG. 1 is a perspective view schematically illustrating a configuration of a watercraft 10 according to an example embodiment of the present invention. In FIG. 1 and the other figures, which will be described below, arrows indicate directions that are based on a position of the watercraft 10. More specifically, in each of the figures, the arrows indicate forward (FRONT), rearward (REAR), leftward (LEFT), rightward (RIGHT), upward (UPPER), and downward (LOWER). A front-rear direction, a right-left direction, and an up-down direction (a vertical direction) are perpendicular to each other.

The watercraft 10 includes a hull 200 and an outboard motor 100.

The hull 200 is a portion of the watercraft 10 that an occupant gets on board. The hull 200 includes a hull body 202 including a living space 204, a helm seat 240 in the living space 204, and a helm system 250 near the helm seat 240. The helm system 250 includes a steering wheel 252, a shift/throttle lever 254, a monitor 256, and an input device 258, for example. The hull 200 also includes a partition wall 220 that defines a rear end of the living space 204, and a transom 210 located at a rear end of the hull 200. A space (hereinafter referred to as a “rear end upper space 206”) exists between the transom 210 and the partition wall 220 in the front-rear direction.

FIG. 2 is a side view schematically illustrating a configuration of the outboard motor 100. FIG. 3 is a side view schematically illustrating a configuration of a portion of the outboard motor 100. In FIG. 3, a configuration of a portion surrounded by a frame border III in FIG. 2 is enlarged. Hereinafter, the outboard motor 100 in a reference attitude will be described unless otherwise specified. The reference attitude is an attitude in which a rotation axis Ac of a crankshaft 124, which will be described below, extends in the up-down direction and a rotation axis Ap of a propeller shaft 112b extends in the front-rear direction (a horizontal direction). Each of the front-rear direction, the right-left direction, and the up-down direction is defined based on the outboard motor 100 in the reference attitude.

The outboard motor 100 generates a propulsive force to propel the watercraft 10. The outboard motor 100 is attached to the transom 210 at a rear portion of the hull 200. The outboard motor 100 includes an outboard motor body 110, a suspension device 150, a steering support 157, a steering actuator 170, and a tilt actuator 180. The steering actuator 170 is an example of a steering.

The outboard motor body 110 includes an engine assembly 120, a propeller 112, a power transmission mechanism 130, a cowl 114, and a casing 116. The cowl 114 and the casing 116 are examples of the body case.

The engine assembly 120 is an assembly of a plurality of components on an engine body 122. The engine assembly 120 includes electrical components 128 (such as a fuse box, an electronic control unit (ECU), and a steering control unit (SCU)) in addition to the engine body 122. The engine assembly 120 is disposed at a relatively upper position in the outboard motor 100.

At least a portion of the engine assembly 120 is accommodated in the cowl 114. The cowl 114 includes a lower cowl 114b that defines a lower portion of the cowl 114 and an upper cowl 114a that defines an upper portion of the cowl 114. The upper cowl 114a is detachably attached to the lower cowl 114b.

The engine body 122 is a prime mover that generates power. For example, the engine body 122 includes an internal combustion engine. The engine body 122 includes a crankshaft 124 that converts reciprocating motion of a piston (not illustrated) into rotating motion. The crankshaft 124 is disposed in such an attitude that the rotation axis Ac thereof extends in the up-down direction. The crankshaft 124 includes a journal 124a that supports the crankshaft 124 by a bearing portion of a crank case (not illustrated), and a spline 124b including a plurality longitudinal grooves to connect with a drive shaft 132, which will be described below. The engine body 122 is an example of the drive source, and the spline 124b is an example of the output shaft.

The propeller 112 is a rotating body including a plurality of blades 112a. The propeller 112 is disposed at a relatively lower position in the outboard motor 100. The propeller 112 generates the propulsive force when rotating.

More specifically, the propeller 112 includes the plurality of blades 112a and the propeller shaft 112b. The propeller shaft 112b is a rod-shaped member, and extends in the front-rear direction at a relatively lower position in the outboard motor 100. A rear end of the propeller shaft 112b protrudes to the outside of the casing 116, and the plurality of blades 112a are attached to the rear end. Along with the rotation of the propeller shaft 112b about the rotation axis Ap, the plurality of blades 112a also rotate.

The power transmission 130 transmits the power generated in the engine assembly 120 to the propeller 112 (the propeller shaft 112b). At least a portion of the power transmission 130 is accommodated in the casing 116. The power transmission 130 includes the drive shaft 132, a shifter 134, and a shift actuator 190.

The drive shaft 132 is a rod-shaped member and extends in the up-down direction at a position below the crankshaft 124 of the engine body 122. A first end 132U of the drive shaft 132 is directly or indirectly coupled to the spline 124b, which is provided at a second end of the crankshaft 124 to transmit torque from the crankshaft 124. In this way, along with rotation of the crankshaft 124, the drive shaft 132 rotates about a drive axis Ad. The first end 132U of the drive shaft 132 is an example of the first end.

The shifter 134 is coupled to a second end 132L of the drive shaft 132 and is directly or indirectly coupled to a front end of the propeller shaft 112b in a torque transmittable manner. The shifter 134 includes a plurality of gears, a clutch that switches engagement of the gears, and a shift shaft 133, for example, and transmits the rotation of the drive shaft 132 to the propeller shaft 112b and switches a rotating direction thereof.

The shift shaft 133 is a rod-shaped member and extends in the up-down direction in front of the drive shaft 132. A first end of the shift shaft 133 extends to a space 163 directly below a steering shaft 158. A second end of the shift shaft 133 is coupled to the front end of the propeller shaft 112b. By rotation of the shift shaft 133, the clutch provided in the shifter 134 is switched between an operation to rotate the drive shaft 132 in a normal rotating direction and an operation to rotate the drive shaft 132 in a reverse rotating direction. When the shifter 134 transmits the rotation of the drive shaft 132 as the rotation in the normal rotating direction to the propeller shaft 112b, the propeller 112 that rotates with the propeller shaft 112b in the normal rotating direction generates the propulsive force in a forward direction. On the contrary, when the shifter 134 transmits the rotation of the drive shaft 132 as the rotation in the reverse rotating direction to the propeller shaft 112b, the propeller 112 that rotates with the propeller shaft 112b in the reverse rotating direction generates the propulsive force in a backward direction. The second end 132L of the drive shaft 132 is an example of the second end.

The shift actuator 190 controls the switching operation of the shifter 134. The shift actuator 190 is disposed in the space 163. The shift actuator 190 is coupled to the first end of the shift shaft 133, and controls the switching operation of the shifter 134 by controlling the rotation of the shift shaft 133. The shift actuator 190 is an electric actuator that includes an electric motor (not illustrated) to make the shift shaft 133 rotate.

The suspension device 150 suspends the outboard motor body 110 from the hull 200. The suspension device 150 includes a pair of right and left clamp brackets 152, a tilt shaft 160, and a swivel bracket 156. Each of the clamp bracket 152 and the swivel bracket 156 is an example of the bracket.

The pair of right and left clamp brackets 152 is disposed behind the hull 200 while being spaced apart from each other in the right-left direction, and is fixed to the transom 210 of the hull 200 by bolts, for example. Each of the clamp brackets 152 includes a tubular support portion 152a including a through-hole extending in the right-left direction.

The tilt shaft 160 is a rod-shaped member. At least a portion of the tilt shaft 160 is rotatably supported in the through-hole of the support portion 152a of the clamp bracket 152. A tilt axis At as a centerline of the tilt shaft 160 defines an axis in the horizontal direction (the right-left direction) of tilting action of the outboard motor 100.

The swivel bracket 156 is sandwiched between the pair of clamp brackets 152, and is supported by the supports 152a of the clamp brackets 152 via the tilt shaft 160 in a manner to be rotatable about the tilt axis At. The swivel bracket 156 is driven to rotate about the tilt axis At with respect to the clamp brackets 152 by the tilt actuator 180 such as a hydraulic cylinder 185. In a space between the pair of clamp brackets 152, for example, the tilt actuator 180 is disposed at a position below the tilt shaft 160.

The steering support 157 includes the steering shaft 158. The steering shaft 158 is a rod-shaped member. In an attitude that extends in a direction tilted with respect to the up-down direction (e.g., the extending direction of the drive shaft 132), the steering shaft 158 is supported by the swivel bracket 156 in a manner to be rotatable about a steering axis As as a centerline of the steering shaft 158.

The steering actuator 170 is disposed at a first end 158U of the steering shaft 158. The steering actuator 170 is of an electric type and includes an electric motor (not illustrated) that outputs a steering force to cause the steering shaft 158 to rotate, and a pair of arms 172 (only one of which is illustrated in FIG. 3) coupled to the steering shaft 158. The steering shaft 158 is driven to rotate about the steering axis As with respect to the swivel bracket 156 via the arms 172 of the steering actuator 170. In a space between the support portions 152a of the pair of clamp brackets 152, for example, the steering actuator 170 is coaxial with the tilt shaft 160.

The outboard motor body 110 is fixed to the steering shaft 158. Thus, when the steering shaft 158 rotates about the steering axis As with respect to the swivel bracket 156, the outboard motor body 110, which is fixed to the steering shaft 158, also rotates about the steering axis As. In this way, a direction of the propulsive force generated by the propeller 112 is changed, and the watercraft 10 is steered.

When the swivel bracket 156 rotates about the tilt axis At with respect to the clamp bracket 152, the steering shaft 158, which is supported by the swivel bracket 156, and the outboard motor body 110, which is fixed to the steering shaft 158, also rotate about the tilt axis At. In this way, the tilting action causes the outboard motor body 110 to rotate in the up-down direction with respect to the hull 200. Due to the tilting action of the outboard motor 100, an angle of the outboard motor body 110 around the tilt axis At can be changed within a range from a tilt-down state where the propeller 112 is located under water (a state where the outboard motor 100 assumes the reference attitude) to a tilt-up state where the propeller 112 is located above a water surface. The tilt actuator 180 can also perform a trim operation to adjust the posture of the watercraft 10 during travel by adjusting the angle of the outboard motor body 110 around the tilt axis At.

The outboard motor body 110 includes a steer-by-wire (hereinafter referred to as “SBW”) system. The SBW system transmits an operation by the helm system 250 to the steering actuator 170 and the shift actuator 190 by electric control. For example, the helm system 250 includes a sensor that detects various operations, or the like, and the SBW system receives an output signal from the sensor or the like and controls the steering actuator 170 and the shift actuator 190 according to the operation by the helm system 250 based on the output signal.

As illustrated in FIGS. 2 and 3, the steering shaft 158 (the steering axis As) is tilted with respect to the drive shaft 132. More specifically, the shortest distance from a second end 158L of the steering shaft 158 to the drive shaft 132 (the drive axis Ad) (a linear distance in a front-rear direction (a direction along the propeller shaft 112b)) is shorter than the shortest distance from the first end 158U of the steering shaft 158 to the drive shaft 132. When viewed in the up-down direction (a direction along the drive shaft 132), the steering actuator 170 is located on an opposite side of the first end 158U of the steering shaft 158 from the second end 158L. That is, the steering actuator 170 is located in front of the first end 158U of the steering shaft 158. The first end 158U of the steering shaft 158 is an example of the first end, and the second end 158L of the steering shaft 158 is an example of the second end. A tilt angle of the steering shaft 158 (the steering axis As) with respect to the drive shaft 132 (the drive axis Ad) may be equal to or greater than about 2 degrees and equal to or less than about 20 degrees, or may be equal to or greater than about 3 degrees and equal to or less than about 10 degrees, for example.

The first end 158U of the steering shaft 158 is fixed to the outboard motor body 110 via a first mount 159U. The first mount 159U extends in the front-rear direction from the first end 158U toward the outboard motor body 110. The second end 158L of the steering shaft 158 is fixed to the outboard motor body 110 via a second mount 159L. The second mount 159L extends in the front-rear direction from the second end 158L toward the outboard motor body 110.

A positional relationship among the steering shaft 158 (the steering axis As), the drive shaft 132 (the drive axis Ad), and a center axis Ag is as follows. The center axis Ag is an imaginary line that is parallel to the drive shaft 132 and extends through a center of gravity G (centroid) of the outboard motor body 110. In the present example embodiment, the center of gravity G of the outboard motor body 110 is the centroid of a lower portion of the casing 116 disposed in the water. The drive shaft 132 is located between the steering shaft 158 and the center axis Ag in the front-rear direction. The shortest distance from the second end 158L of the steering shaft 158 to the center axis Ag (a linear distance in the front-rear direction) is shorter than the shortest distance from the first end 158U of the steering shaft 158 to the center axis Ag. In the present specification, “parallel” is not limited to an angle of 180 degrees (complete parallel) defined by a line A and a line B but also includes a tilt of about ±5 degrees.

A positional relationship among the steering shaft 158 (the steering axis As), the drive shaft 132 (the drive axis Ad), and the propeller shaft 112b (the rotation axis Ap) is as follows. An intersection point between the steering axis As and the rotation axis Ap is set as a first intersection point Ps, and an intersection point between the drive axis Ad and the rotation axis Ap is set as a second intersection point Pd. The first intersection point Ps is located in front of the second intersection point Pd (on an opposite side from the plurality of blades 112a). The steering axis As is an example of the first extension line, and the drive axis Ad is an example of the second extension line.

A positional relationship among the steering shaft 158 (the steering axis As), the center axis Ag, and the propeller shaft 112b (the rotation axis Ap) is as follows. An intersection point between the center axis Ag and the rotation axis Ap is set as a third intersection point Pg. The first intersection point Ps is located in front of the third intersection point Pg (on the opposite side from the plurality of blades 112a). The center axis Ag is an example of the third extension line.

A positional relationship among the steering shaft 158 (the steering axis As), the drive shaft 132 (the drive axis Ad), and the shift shaft 133 is as follows. The steering axis As extends between the first end 132U of the drive shaft 132 and the first end of the shift shaft 133. When viewed in the up-down direction, at least a portion of the steering shaft 158 overlaps the shift shaft 133.

The arrangement of the steering actuator 170 is as follows. The steering actuator 170 is disposed in the space between the support portions 152a of the pair of clamp brackets 152 as described above. The space 163 is located between the second end 158L of the steering shaft 158 and the shifter 134 (the shift shaft 133) in the up-down direction.

At least a portion of the steering actuator 170 is located at the same position as the steering shaft 158 in the up-down direction (a direction parallel to the drive shaft 132). More specifically, when viewed in the front-rear direction, a portion (a lower portion) of the steering actuator 170 overlaps the first end 158U of the steering shaft 158.

FIG. 4 is a view illustrating a relationship between a steering shaft 158A of an outboard motor 100A and steering torque in a comparative example. FIG. 4 schematically illustrates a configuration of the outboard motor 100A in the comparative example. The outboard motor 100A of the comparative example differs from the outboard motor 100 of the present example embodiment mainly in that the steering shaft 158A is parallel to the drive axis Ad. The shortest distance L1 between the steering axis As and the center of gravity G is relatively long. Thus, a relatively large steering torque load (=F×L1) is generated on the steering shaft 158A by a force that the lower portion (the propeller-side portion) of the casing 116, which is disposed in the water, receives due to a water pressure. In addition, since the steering shaft 158A extends along the up-down direction, a distance H1 between a second end of the steering shaft 158A and an upper surface of the casing 116 is relatively short. As a result, a degree of freedom in arrangement of the shift actuator 190 is restricted.

FIG. 5 is a view illustrating a relationship between the steering shaft 158 of the outboard motor 100 and the steering torque according to the present example embodiment. FIG. 5 schematically illustrates the configuration of the outboard motor 100. The steering shaft 158 is tilted with respect to the drive axis Ad. The shortest distance L2 between the steering axis As and the center of gravity G is relatively short. Thus, a relatively small steering torque load (=F×L2) is generated on the steering shaft 158 by the force that the lower portion (the propeller-side portion) of the casing 116, which is disposed in the water, receives due to the water pressure. In the present example embodiment, the steering support 157 and the steering actuator 170 can be reduced in size and weight to the extent that the strength required for the components of the steering support 157 and the steering actuator 170 is low compared to the comparative example.

In the present example embodiment, when viewed in the up-down direction, the steering actuator 170 is located on the opposite side of the first end 158U of the steering shaft 158 from the second end 158L. Accordingly, in the present example embodiment, for example, compared to a configuration that the steering actuator 170 is located on the same side as the second end 158L from the first end 158U when viewed in the up-down direction, the distance between the steering actuator 170 and the first end 158U of the steering shaft 158 is short. Thus, transmission of the steering force from the steering actuator 170 to the steering shaft 158 is improved.

In the present example embodiment, the first end 158U of the steering shaft 158 is located at the same height as a first end of the steering shaft 158A in the comparative example. The second end 158L of the steering shaft 158 is located at a higher position than the second end of the steering shaft 158A in the comparative example. A distance H2 between the second end 158L of the steering shaft 158 and the upper surface of the casing 116 is relatively long. As a result, the large space 163 is provided, and the degree of freedom in arrangement of the shift actuator 190 is improved.

In the present example embodiment, an imaginary straight line Lt that connects a joint point between the first mount 159U and the outboard motor body 110 and a joint point between the second mount 159L and the outboard motor body 110 is parallel to the drive axis Ad. That is, although the steering shaft 158 is tilted with respect to the drive axis Ad, the joint point of the first mount 159U and the joint point of the second mount 159L that support the steering shaft 158 are located on a straight line that is parallel to the drive axis Ad. Thus, it is possible to reduce or prevent vibrations (vibrations in the front-rear direction) caused by the difference between the two positions, each of which is applied with the force to be transmitted from the steering shaft 158 to the outboard motor body 110. The imaginary straight line Lt may not be parallel to the drive axis Ad, but the imaginary straight line Lt is closer to parallel with the drive axis Ad than the steering axis As is with the drive axis Ad.

The technologies disclosed herein are not limited to the above-described example embodiments but can be modified in various ways without departing from the gist of the present invention, and, for example, the following modifications can be made.

The configurations of the watercraft 10 according to the above example embodiments are merely examples, and various modifications can be made thereto. For example, in the above example embodiments, the drive source is the engine body 122, but is not limited thereto, and may be an electric motor or the like, for example. When the drive source is an electric motor, a rotation shaft of the electric motor is an example of the output shaft.

In the above example embodiments, each of the steering actuator 170 and the shift actuator 190 is of the electric type, but may be of a hydraulic type including a hydraulic cylinder, or the like. In the above example embodiments, the steering actuator converts energy such as electricity, an air pressure, or a hydraulic pressure into mechanical motion, but is not limited thereto, and may be a manual steering that includes a lever to rotate the steering shaft when a person operates the lever. In the above example embodiments, the tilt actuator 180 is of the hydraulic type, but may be of the electric type or the like.

In the above example embodiments, the shortest distance from the second end 158L of the steering shaft 158 to the drive shaft 132 may be longer than the shortest distance from the first end 158U of the steering shaft 158 to the drive shaft 132. The shortest distance from the second end 158L of the steering shaft 158 to the center axis Ag may be longer than the shortest distance from the first end 158U of the steering shaft 158 to the center axis Ag. Even in these cases, the large space 163 can be provided by tilting the steering shaft 158. The steering actuator 170 may be accommodated in the cowl 114. In the above example embodiments, when viewed in the front-rear direction, the steering actuator 170 may not overlap the first end 158U of the steering shaft 158.

The steering actuator 170 may be disposed at a different position from the tilt axis At. For example, the steering actuator 170 may be disposed above the first end 158U of the steering shaft 158 or may be disposed behind the first end 158U.

In the above example embodiments, the first intersection point Ps may coincide with the second intersection point Pd, or may be located behind (on the side of the plurality of blades 112a) the second intersection point Pd. In the above example embodiments, the first intersection point Ps may be located at the third intersection point Pg, or may be located behind (on the side of the plurality of blades 112a) the third intersection point Pg. In the above example embodiments, the steering axis As may extend through a rear side of the first end 132U of the drive shaft 132 or a front side of the first end of the shift shaft 133. In the above example embodiments, when viewed in the up-down direction, the steering shaft 158 may not overlap the shift shaft 133.

In the above example embodiments, the joint point of the first mount 159U and the joint point of the second mount 159L that support the steering shaft 158 may be located on a straight line that is tilted with respect to the drive axis Ad.

In an example embodiment, when viewed in the up-down direction, the steering actuator 170 may be located on the same side as the second end 158L of the steering shaft 158 from the first end 158U. In the present example embodiment, when viewed in the up-down direction, the tilt actuator 180 overlaps the steering actuator 170, but may not overlap the steering actuator 170.

An example embodiment of the present invention may be an outboard motor including a body case, a drive source in the body case and including an output shaft, a propeller rotatably mounted to the body case, a drive shaft in the body case and including a first end coupled to the output shaft of the drive source and a second end coupled to the propeller, a bracket attachable to a hull, a steering support including a steering shaft including a first end and a second end to rotatably support the body case about the steering shaft with respect to the bracket, and a steering at the first end of the steering shaft to output a steering force to cause the body case to rotate, wherein the steering shaft is tilted with respect to the drive shaft such that a distance from the first end to the drive shaft and a distance from the second end to the drive shaft differ from each other, the outboard motor further including a shifter to switch an operation state of the propeller, and a shift actuator to control the switching operation of the shifter located in a space between the shifter and the second end of the steering shaft.

While example 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.

Claims

1. An outboard motor comprising:

a body case;
a drive source in the body case and including an output shaft;
a propeller rotatably mounted to the body case;
a drive shaft in the body case and including a first end coupled to the output shaft and a second end coupled to the propeller;
a bracket attachable to a hull;
a steering support including a steering shaft including a first end and a second end to rotatably support the body case about the steering shaft with respect to the bracket; and
a steering located at the first end of the steering shaft to output a steering force to cause the body case to rotate; wherein
the steering shaft is tilted with respect to the drive shaft such that a distance from the first end of the steering shaft to the drive shaft and a distance from the second end of the steering shaft to the drive shaft differ from each other; and
the steering is located on an opposite side of the first end of the steering shaft from the second end of the steering shaft when viewed in an up-down direction.

2. The outboard motor according to claim 1, wherein

a straight line parallel to the drive shaft and extending through a center of gravity of the outboard motor defines a center axis;
the drive shaft is located between the steering shaft and the center axis; and
the distance from the second end of the steering shaft to the drive shaft is shorter than the distance from the first end of the steering shaft to the drive shaft.

3. The outboard motor according to claim 1, wherein

the propeller includes a propeller shaft and a plurality of blades fixed to the propeller shaft; and
a first intersection point of a first extension line extending from the steering shaft and the propeller shaft is located on an opposite side of a second intersection point of a second extension straight line extending from the drive shaft and the propeller shaft from the plurality of blades.

4. The outboard motor according to claim 1, wherein

a straight line parallel to the drive shaft and extending through a center of gravity of the outboard motor defines a center axis;
the propeller includes a propeller shaft and a plurality of blades fixed to the propeller shaft; and
a first intersection point of a first extension line extending from the steering shaft and the propeller shaft is located on an opposite side of a third intersection point of the center axis and the propeller shaft from the plurality of blades.

5. The outboard motor according to claim 1, further comprising:

a first mount extending from the first end of the steering shaft toward the body case connected to the body case; and
a second mount extending from the second end of the steering shaft toward the body case connected to the body case; wherein
an imaginary line connecting a first joint point between the first mount and the body case and a second joint point between the second mount and the body case is closer to parallel with the drive shaft than the steering shaft is with the drive shaft.

6. The outboard motor according to claim 1, wherein, when viewed in a front-rear direction, at least a portion of the steering overlaps the steering shaft.

7. The outboard motor according to claim 1, wherein

the bracket includes a tilt shaft extending in a direction perpendicular to the direction along the drive shaft defines a tilt axis of the body case; and
the steering is located on the tilt axis.

8. The outboard motor according to claim 7, further comprising:

a tilt actuator to output a rotating force to cause the body case to tilt; wherein
when viewed in the up-down direction, the tilt actuator overlaps the steering.

9. The outboard motor according to claim 1, further comprising:

a shifter to switch an operation state of the propeller; and
a shift actuator to control the switching of the operation state of the shifter; wherein
the shift actuator is located in a space between the shifter and the second end of the steering shaft.

10. The outboard motor according to claim 9, wherein

the propeller includes a propeller shaft and a plurality of blades fixed to the propeller shaft;
the shifter includes a shift shaft extending from the shift actuator to an end of the propeller shaft on an opposite side from the plurality of blades; and
a first extension line extending from the steering shaft extends between the second end of the drive shaft and the shift shaft.

11. The outboard motor according to claim 10, wherein, at least a portion of the steering shaft overlaps the shift shaft in the up-down direction.

12. The outboard motor according to claim 9, wherein the shift actuator is electric.

13. The outboard motor according to claim 1, wherein the steering is electric.

14. A watercraft comprising:

a hull; and
the outboard motor according to claim 1 attached to a rear portion of the hull.

15. An outboard motor comprising:

a body case;
a drive source in the body case and including an output shaft;
a propeller rotatably mounted to the body case;
a drive shaft in the body case and including a first end coupled to the output shaft and a second end coupled to the propeller;
a steering support including a steering shaft including a first end and a second end to rotatably support the body case about the steering shaft; and
a steering at the first end of the steering shaft to output a steering force to cause the body case to rotate; wherein
the steering shaft is tilted with respect to the drive shaft such that a distance from the first end of the steering shaft to the drive shaft and a distance from the second end of the steering shaft to the drive shaft differ from each other; and
the steering is located closer to the second end of the steering shaft than to the first end of the steering shaft in an up-down direction.
Patent History
Publication number: 20260200566
Type: Application
Filed: Jan 13, 2026
Publication Date: Jul 16, 2026
Inventors: Yuma SEGAWA (Shizuoka), Tomohiro HAGI (Shizuoka), Hiroaki TAKASE (Shizuoka)
Application Number: 19/447,057
Classifications
International Classification: B63H 20/12 (20060101); B63H 20/10 (20060101); B63H 20/20 (20060101);