Patent Description:
A marine propulsion unit is known in general. Such a marine propulsion unit is disclosed in <CIT>, for example.

<CIT> discloses a marine propulsion unit including a power supply wire to supply power, a signal wire to transmit a predetermined signal, and a hollow steering shaft to steerably support a duct. The power supply wire and the signal wire are introduced into a marine propulsion unit main body by being directly inserted into the steering shaft from an upper end of the hollow steering shaft.

In the marine propulsion unit disclosed in <CIT>, the power supply wire and the signal wire are directly inserted into the steering shaft. Thus, when the duct is steered about the steering shaft, it is necessary to prevent action of relatively large torsional and bending stresses on the power supply wire and the signal wire, and the steering angle of the duct is constrained.

It is an object of the present invention to provide a marine propulsion unit that significantly reduces or prevents a constraint on the steering angle of a duct. According to the present invention, said object is solved by a marine propulsion unit having the features of independent claim <NUM>. Preferred embodiments are laid down in the dependent claims.

A marine propulsion unit according to a preferred embodiment includes a duct including a stator, a propeller including a rim including a rotor configured to face the stator, and a blade provided radially inwardly of the rim, a steering shaft configured to extend in an upward-downward direction so as to rotatably support the duct, a casing configured to be rotated by the steering shaft, provided above the duct, and configured to house the steering shaft and a controller configured or programmed to control driving of the propeller, a power supply wire configured to supply power from a power source to the stator, and a signal wire configured to transmit a drive signal to the controller. The power supply wire and the signal wire are located outside and along the casing so as to pass in front of the steering shaft along a rotation direction of the steering shaft from a first side of the casing to a second side of the casing in a right-left direction in a plan view.

In a marine propulsion unit according to a preferred embodiment, the power supply wire and the signal wire are located outside and along the casing so as to pass in front of the steering shaft along the rotation (steering) direction of the steering shaft from the first side of the casing to the second side of the casing in the right-left direction in the plan view. Accordingly, the power supply wire and the signal wire are located so as to be wound around the steering shaft in an arcuate shape having a relatively small curvature (an arcuate shape having a large radius) along the casing. Furthermore, the power supply wire and the signal wire are located along the rotation direction of the steering shaft such that when the duct is steered about the steering shaft, the duct is steered while a state in which the power supply wire and the signal wire are wound in an arcuate shape having a relatively small curvature (an arcuate shape having a large radius) along the casing is maintained. Therefore, large torsion (deformation) of the power supply wire and the signal wire is significantly reduced or prevented during steering of the duct, and thus a constraint on the steering angle of the duct is significantly reduced or prevented. Furthermore, the power supply wire and the signal wire are located along the casing such that spaces to provide the power supply wire and the signal wire are relatively reduced.

In a marine propulsion unit according to a preferred embodiment, the power supply wire and the signal wire are preferably located along the casing so as to pass in front of the casing. Accordingly, using the front surface of the casing, the power supply wire and the signal wire are easily located so as to be wound around the steering shaft in an arcuate shape having a relatively small curvature along the casing.

In a marine propulsion unit according to a preferred embodiment, the power supply wire and the signal wire preferably include first portions on the first side in the right-left direction, and second portions configured to be introduced into the casing on the second side in the right-left direction. Accordingly, as compared with a case in which the power supply wire and the signal wire are located on only one side in the right-left direction, the power supply wire and the signal wire have a larger arcuate shape (longer path length). Therefore, when the duct is steered about the steering shaft, the duct is steered while a state in which the power supply wire and the signal wire are wound in an arcuate shape having a relatively small curvature (an arcuate shape having a large radius) along the casing in a larger range is maintained. Consequently, large torsion (deformation) of the power supply wire and the signal wire is further significantly reduced or prevented during steering of the duct, and thus a constraint on the steering angle of the duct is further significantly reduced or prevented.

In such a case, the casing preferably includes, on the second side in the right-left direction, an introduction hole configured to allow the second portions to be introduced into the casing therethrough, and the second portions are preferably configured to be introduced into the introduction hole obliquely from a lower front side toward an upper rear side, as viewed in the right-left direction. Accordingly, the power supply wire and the signal wire that hang down due to gravity are introduced from below, and thus action of large torsional and bending stresses on the power supply wire and the signal wire is further significantly reduced or prevented.

In a marine propulsion unit according to a preferred embodiment, the power supply wire is preferably configured to be more vulnerable to torsion and easier to bend than the signal wire, and the signal wire is preferably configured to be harder to bend and more resistant to torsion than the power supply wire. Accordingly, even when the power supply wire that is relatively vulnerable to torsion and the signal wire that is relatively hard to bend are used, action of large torsional and bending stresses on the power supply wire and the signal wire is significantly reduced or prevented. Therefore, the steerable marine propulsion unit is reliably wired.

In a marine propulsion unit according to a preferred embodiment, the casing preferably includes a curved surface configured to protrude forward in a plan view, and the power supply wire and the signal wire are preferably curved along the curved surface. Accordingly, the power supply wire and the signal wire are located along the curved surface, and thus when the duct is steered about the steering shaft, the duct is steered while a state in which the power supply wire and the signal wire are curved more smoothly and are wound in an arcuate shape having a relatively small curvature (an arcuate shape having a large radius) along the casing is maintained. Therefore, large torsion (deformation) of the power supply wire and the signal wire is further significantly reduced or prevented during steering of the duct. Thus, action of large torsional and bending stresses on the power supply wire and the signal wire is further significantly reduced or prevented, and thus a constraint on the steering angle of the duct is further significantly reduced or prevented.

In such a case, the curved surface preferably has a substantially arcuate shape that protrudes forward in the plan view, and the power supply wire and the signal wire are preferably placed in a substantially elliptical shape along the curved surface having the substantially arcuate shape. Note that the substantially arcuate shape includes a precise arcuate shape and shapes similar to the arcuate shape. Furthermore, the substantially elliptical shape includes a precise elliptical shape and shapes similar to the elliptical shape. Accordingly, the power supply wire and the signal wire are easily placed in a substantially elliptical shape along the curved surface, and thus the power supply wire and the signal wire are placed along the casing in a larger range as compared with a case in which the power supply wire and the signal wire are placed in a circular shape. Therefore, action of large torsional and bending stresses on the power supply wire and the signal wire is further significantly reduced or prevented.

In a marine propulsion unit according to a preferred embodiment, the casing preferably has a streamlined shape with a rotation axis direction of the propeller as a longitudinal direction, and the power supply wire and the signal wire are preferably located along the casing having the streamlined shape such that lower ends thereof are submerged in water. Accordingly, using up to a region in which the power supply wire and the signal wire are submerged in water as spaces to provide the power supply wire and the signal wire, the power supply wire and the signal wire are located along the casing, and thus entanglement of foreign matter with the power supply wire and the signal wire is significantly reduced or prevented.

In a marine propulsion unit according to a preferred embodiment, the power supply wire and the signal wire preferably include lower ends above the duct. Accordingly, obstruction of the power supply wire and the signal wire to the flow of water generated by the propeller installed in the duct is prevented.

In a marine propulsion unit according to a preferred embodiment, the power supply wire and the signal wire are preferably located along the casing while being inclined so as to be located more forward toward a lower side. Accordingly, the power supply wire and the signal wire are located along the casing in a larger range as compared with a case in which the power supply wire and the signal wire are located only in a substantially horizontal direction or a substantially vertical direction. Therefore, action of large torsional and bending stresses on the power supply wire and the signal wire is further significantly reduced or prevented.

In the marine propulsion unit according to the invention, the casing includes, on the second side in the right-left direction, an introduction hole configured to allow the power supply wire and the signal wire to be introduced into the casing therethrough, the marine propulsion unit further includes, above the casing, a cowling configured to allow the power supply wire and the signal wire to pass therethrough, and the cowling includes, on a side opposite to the introduction hole in the right-left direction, a lead-out port configured to lead the power supply wire and the signal wire from within the cowling to the first side of the casing in the right-left direction. Accordingly, the power supply wire and the signal wire are led downward from the lead-out port located on the side opposite to the introduction hole in the right-left direction and above the introduction hole, and thus the power supply wire and the signal wire are easily placed along the casing while hanging down due to gravity.

In such a case, the lead-out port preferably has an elongated shape that extends in a forward-rearward direction, and the power supply wire and the signal wire are preferably configured to be moved in the forward-rearward direction inside the lead-out port along the lead-out port as the casing is rotated. Accordingly, as compared with a case in which the power supply wire and the signal wire are completely constrained by the lead-out port, torsional and bending stresses applied to the power supply wire and the signal wire during steering of the duct are reduced, and a constraint on the steering angle of the duct is further significantly reduced or prevented.

A marine propulsion unit according to a preferred embodiment preferably further includes a restrainer configured to bundle the power supply wire and the signal wire at a predetermined position inside the cowling and allow the power supply wire and the signal wire to pass through the predetermined position. Accordingly, the power supply wire and the signal wire are constrained at a position spaced relatively apart from the casing to be steered. That is, the power supply wire and the signal wire are constrained at a position at which the influence of steering is relatively small. Therefore, action of large torsional and bending stresses on the power supply wire and the signal wire is further significantly reduced or prevented.

In such a case, a marine propulsion unit according to a preferred embodiment preferably further includes a trim-tilt mechanism configured to rotate a marine propulsion unit main body in the upward-downward direction, and the restrainer is preferably configured to be freely rotatable about an axis that extends in the right-left direction when the marine propulsion unit main body is rotated in the upward-downward direction by the trim-tilt mechanism. Accordingly, when the marine propulsion unit main body is rotated in the upward-downward direction by the trim-tilt mechanism, the restrainer is rotated to reduce torsional and bending stresses applied to the power supply wire and the signal wire.

A marine propulsion unit according to a preferred embodiment preferably further includes a trim-tilt shaft, and the predetermined position is preferably located closer to the casing than the trim-tilt shaft. Accordingly, the power supply wire and the signal wire are constrained at a position spaced apart by an appropriate distance not too far from the casing. Thus, large movement of the power supply wire and the signal wire located along the casing is prevented during steering of the duct.

The above and other elements, features, steps, characteristics and advantages of preferred embodiments will become more apparent from the following detailed description of the preferred embodiments with reference to the attached drawings.

Preferred embodiments are hereinafter described with reference to the drawings.

The structure of a marine vessel <NUM> including a marine propulsion unit <NUM> according to preferred embodiments is now described with reference to <FIG>. In the figures, arrow FWD represents the forward movement direction of the marine vessel <NUM>, and arrow BWD represents the reverse movement direction of the marine vessel <NUM>. Furthermore, arrow R represents the starboard (right) direction of the marine vessel <NUM>, and arrow L represents the portside (left) direction of the marine vessel <NUM>. The right side (R direction) is an example of a "first side in a right-left direction", and the left side (L direction) is an example of a "second side in a right-left direction".

As shown in <FIG> and <FIG>, the marine vessel <NUM> includes a hull 101a and the marine propulsion unit <NUM>.

The hull 101a includes a power source P (battery) to supply power to the marine propulsion unit <NUM> via power supply wires <NUM>, and an operator S to transmit various drive signals (control signals) to the marine propulsion unit <NUM> via a signal wire <NUM>. The operator S includes a remote control and a steering wheel, for example, operated by a user.

The marine propulsion unit <NUM> is installed at the stern (transom) of the hull 101a. The marine propulsion unit <NUM> is driven by power supplied from the power source P via the power supply wires <NUM>. The marine propulsion unit <NUM> is driven based on a drive signal transmitted from the operator S via the signal wire <NUM>. That is, the marine propulsion unit <NUM> rotates and steers a propeller <NUM> (duct <NUM>) based on the drive signal transmitted from the operator S via the signal wire <NUM>, for example.

The marine propulsion unit <NUM> includes an electric propulsion device to propel the marine vessel <NUM> (hull 101a). The marine propulsion unit <NUM> includes a bracket B, a trim-tilt mechanism <NUM>, a restrainer <NUM>, the duct <NUM> including a stator <NUM>, the propeller <NUM> including a rim <NUM> and blades <NUM>, a steering shaft <NUM>, a steering <NUM>, a casing <NUM>, a cowling <NUM>, the power supply wires <NUM>, and the signal wire <NUM>. The structure of each portion of the marine propulsion unit <NUM> is now sequentially described.

The bracket B supports a marine propulsion unit main body 100a. The marine propulsion unit main body 100a refers to an entire structure (excluding the bracket B) rotated about a trim-tilt shaft B30 by the trim-tilt mechanism <NUM>.

The bracket B includes a fixed bracket B10 and a movable bracket B20.

The fixed bracket B10 is fixed to the stern. The fixed bracket B10 includes the trim-tilt shaft B30 that extends in the right-left direction. The movable bracket B20 directly supports the marine propulsion unit main body 100a. The movable bracket B20 rotates in an upward-downward direction about the trim-tilt shaft B30 together with the marine propulsion unit main body 100a.

The fixed bracket B10 includes a shaft B11 that extends in the right-left direction. The shaft B11 rotatably supports a lower end of the trim-tilt mechanism <NUM> (cylinder).

The movable bracket B20 includes a shaft B21 that extends in the right-left direction. The shaft B21 is rotatably supported by an upper end of the trim-tilt mechanism <NUM> (cylinder). The shaft B21 is directly pushed up by extension of the trim-tilt mechanism <NUM>, and is directly pushed down by contraction of the trim-tilt mechanism <NUM>. When the shaft B21 is directly pushed up by the trim-tilt mechanism <NUM>, the marine propulsion unit main body 100a is rotated upward. When the shaft B21 is directly pushed down by the trim-tilt mechanism <NUM>, the marine propulsion unit main body 100a is rotated downward.

The trim-tilt mechanism <NUM> rotates the marine propulsion unit main body 100a in the upward-downward direction. The trim-tilt mechanism <NUM> includes a tubular cylinder including an expandable and contractable rod.

The upper end of the trim-tilt mechanism <NUM> rotatably supports the shaft B21, as described above. The restrainer <NUM> is rotatably installed on the shaft B21 side by side with the upper end of the trim-tilt mechanism <NUM>. That is, the upper end of the trim-tilt mechanism <NUM> and the restrainer <NUM> are located adjacent to each other in the right-left direction (see <FIG>).

The shaft B21 is located rearward of the trim-tilt shaft B30. That is, the shaft B21 is positioned closer to the casing <NUM> than the trim-tilt shaft B30 in a forward-rearward direction. Therefore, the restrainer <NUM> is positioned closer to the casing <NUM> than the trim-tilt mechanism <NUM> in the forward-rearward direction. The shaft B21 (the restrainer <NUM> and the upper end of the trim-tilt mechanism <NUM>) is located inside the cowling <NUM>.

As shown in <FIG>, the restrainer <NUM> includes a cylindrical portion <NUM> through which the shaft B21 is inserted and an annular restraining portion <NUM> that protrudes outward from the outer surface of the cylindrical portion <NUM> to bundle the power supply wires <NUM> and the signal wire <NUM>.

The cylindrical portion <NUM> (restrainer <NUM>) is rotatable with respect to the shaft B21. The restraining portion <NUM> includes a through-hole, and the power supply wires <NUM> and the signal wire <NUM> are bundled by passing through the through-hole. Therefore, the restrainer <NUM> bundles the power supply wires <NUM> and the signal wire <NUM> at a predetermined position inside the cowling <NUM> and allows the power supply wires <NUM> and the signal wire <NUM> to pass through the predetermined position. The predetermined position refers to the vicinity of the shaft B21. That is, the predetermined position is located closer to the casing <NUM> than the trim-tilt shaft B30. The restraining portion <NUM> is located above the cylindrical portion <NUM>, and allows the power supply wires <NUM> and the signal wire <NUM> to pass therethrough above the cylindrical portion <NUM>.

As described above, the shaft B21 is inserted through the restrainer <NUM>, and the restrainer <NUM> is rotatable with respect to the shaft B21. That is, the restrainer <NUM> is freely rotatable about an axis (shaft B21) that extends in the right-left direction when the marine propulsion unit main body 100a is rotated by the trim-tilt mechanism <NUM>.

If the restrainer <NUM> were fixed to the shaft B21, rear portions (portions rearward of the restrainer <NUM>) of the power supply wires <NUM> and the signal wires <NUM> would be moved upward (downward) together with the restrainer <NUM> when the shaft B21 moves (rotates) upward (downward) about the trim-tilt shaft B30. Consequently, the power supply wires <NUM> and the signal wire <NUM> receive a large bending stress inside the cowling <NUM>, and it is not preferable.

As shown in <FIG> and <FIG>, the duct <NUM> has a tubular shape. The duct <NUM> includes the stator <NUM>. The propeller <NUM> is rotatably positioned radially inwardly of the tubular duct <NUM>. The propeller <NUM> includes the rim <NUM> including a rotor 40a and the blades <NUM>.

The stator <NUM> includes a cylindrical and annular winding that surrounds the propeller <NUM>, and power is supplied to the winding such that a magnetic field is generated. The magnetic force of the stator <NUM> acts on the rotor 40a such that the propeller <NUM> is rotated. That is, the stator <NUM> of the duct <NUM> and the rotor 40a of the propeller <NUM> define an electric motor.

The rim <NUM> of the propeller <NUM> has a tubular shape and is located outside the blades <NUM>. Furthermore, the rim <NUM> faces the stator <NUM> from the inside. The blades <NUM> are positioned radially inwardly of the rim <NUM> from the inner peripheral surface of the rim <NUM>. The rotor 40a and the stator <NUM> face each other at a predetermined interval in the radial direction of the duct <NUM>.

The steering shaft <NUM> extends in the upward-downward direction and supports the duct <NUM> such that the duct <NUM> is rotatable (steerable) in the right-left direction. Specifically, the steering shaft <NUM> is rotatably supported by the steering <NUM> via a bearing (not shown). Furthermore, the steering shaft <NUM> supports, via a bearing (not shown), the casing <NUM> that is integral and unitary with the duct <NUM>. The steering shaft <NUM> is located (inserted) inside the steering <NUM> and the casing <NUM> in the order of the steering <NUM> and the casing <NUM> from the upper side to the lower side.

As shown in <FIG>, the steering <NUM> rotates (steers) the steering shaft <NUM>. Consequently, the steering <NUM> steers the duct <NUM> and the casing <NUM> together with the steering shaft <NUM>. As an example, the steering <NUM> steers the duct <NUM> and the casing <NUM> together with the steering shaft <NUM> in a relatively large angular range of <NUM> degrees or more. The steering <NUM> includes a housing <NUM>, and an electric motor <NUM> and a worm gear <NUM> located inside the housing <NUM>.

The housing <NUM> is hollow and watertight. The housing <NUM> is fixed to a bottom plate <NUM> (see <FIG>), which is described below, of the cowling <NUM> (see <FIG>) from below. The housing <NUM> is located between the upper cowling <NUM> and the lower casing <NUM> in the upward-downward direction. The housing <NUM> is one size smaller than the cowling <NUM> and the bottom plate <NUM> in a plan view.

The electric motor <NUM> rotates the worm gear <NUM>. The worm gear <NUM> contacts the steering shaft <NUM>, and transmits the driving force of the electric motor <NUM> to the steering shaft <NUM> to rotate (steer) the steering shaft <NUM>.

The casing <NUM> shown in <FIG> and <FIG> is rotated by the steering shaft <NUM>. Furthermore, the casing <NUM> is fixed to the duct <NUM> from above so as to rotate (steer) together with the duct <NUM>. The casing <NUM> is hollow and watertight, and houses the steering shaft <NUM>, a controller <NUM>, and an AC-DC converter <NUM>. The controller <NUM> includes a driver to drive the propeller <NUM> and the steering <NUM>, and controls driving of the propeller <NUM> and the steering <NUM>. The controller <NUM> controls each portion of the marine propulsion unit <NUM> based on various signals received via the signal wire <NUM>. The controller <NUM> includes a CPU and a memory. The AC-DC converter <NUM> converts AC power supplied via the power supply wires <NUM> into DC power, and supplies the DC power to the controller <NUM>, the stator <NUM>, the electric motor <NUM>, etc..

The casing <NUM> includes an introduction hole <NUM> through which second portions 92b described below, which are portions of the power supply wires <NUM> and the signal wire <NUM> located on the left side of the casing <NUM>, are inserted into the casing <NUM>. The introduction hole <NUM> is provided on the second side (left side) of the casing <NUM> in the right-left direction. In the introduction hole <NUM>, a grommet G that keeps the inside of the casing <NUM> watertight is installed.

The casing <NUM> has a streamlined shape (fin shape) with the rotation axis direction of the propeller <NUM> as a longitudinal direction (see <FIG>). That is, the casing <NUM> is submerged in water in the used state (i.e., the casing <NUM> is located at a position that contacts water), and has a shape that reduces resistance received from water during propulsion. The length of the casing <NUM> in the rotation axis direction of the propeller <NUM> is longer than the length of the casing <NUM> in the upward-downward direction.

The casing <NUM> includes a curved surface <NUM> that protrudes forward in a plan view (see <FIG>). The curved surface <NUM> has a substantially arcuate shape that protrudes forward in the plan view. The introduction hole <NUM> is located on the curved surface <NUM>. That is, the introduction hole <NUM> is located in a forward portion of the casing <NUM>.

The cowling <NUM> is located above the casing <NUM> and the steering <NUM>. The cowling <NUM> is an external component that covers a portion of the marine propulsion unit main body 100a above the steering <NUM>. The power supply wires <NUM> and the signal wire <NUM> are introduced from the hull 101a into the cowling <NUM>, and pass through the cowling <NUM>. As described above, the restrainer <NUM> (predetermined position) is located inside the cowling <NUM>. That is, the power supply wires <NUM> and the signal wire <NUM> are bundled inside the cowling <NUM>.

The cowling <NUM> includes the bottom plate <NUM> that extends in a horizontal direction above the steering <NUM>, and a cowling main body <NUM> (cover) on the bottom plate <NUM> from above. The cowling main body <NUM> is a member that covers various components such as the power supply wires <NUM> and the signal wire <NUM> to significantly reduce or prevent exposure thereof.

The cowling <NUM> (bottom plate <NUM>) includes a lead-out port 80a on a side (right side) opposite to the introduction hole <NUM> of the casing <NUM> in the right-left direction. The lead-out port 80a leads the power supply wires <NUM> and the signal wire <NUM> from within the cowling <NUM> to the first side (right side) of the casing <NUM> in the right-left direction. The lead-out port 80a includes a notch at a right end of the bottom plate <NUM>. The lead-out port 80a may include a through-hole at the right end of the bottom plate <NUM>.

The lead-out port 80a has an elongated shape that extends in the forward-rearward direction (see <FIG>), and is located such that the power supply wires <NUM> and the signal wire <NUM> that pass through the lead-out port 80a are movable in the forward-rearward direction in the lead-out port 80a. The lead-out port 80a includes a front end in the vicinity of the steering shaft <NUM> and a rear end rearward of the steering shaft <NUM> in the forward-rearward direction.

The expression "the power supply wires <NUM> and the signal wire <NUM> that pass through the lead-out port 80a are movable in the forward-rearward direction" indicates that the power supply wires <NUM> and the signal wire <NUM> are movable when the casing <NUM> (duct <NUM>) is rotated by the steering <NUM>. Specifically, as shown in (A) of <FIG>, when a rear end of the casing <NUM> is located on the right side, the power supply wires <NUM> and the signal wire <NUM> are located in a forward portion of the inside of the lead-out port 80a. When the casing <NUM> (duct <NUM>) is rotated by the steering <NUM> such that the rear end of the casing <NUM> is located on the left side, the power supply wires <NUM> and the signal wire <NUM> are moved inside the lead-out port 80a from the front side toward the rear side, as shown in (B) and (C) of <FIG>.

The lead-out port 80a of the cowling <NUM> may include a low-friction surface (not shown). The low-friction surface includes a function of preventing damage of the power supply wires <NUM> and the signal wire <NUM> due to contact (rubbing) of the power supply wires <NUM> and the signal wire <NUM> with the inner surface of the lead-out port 80a when the power supply wires <NUM> and the signal wire <NUM> that pass through the lead-out port 80a are moved in the forward-rearward direction due to steering of the duct <NUM>. The low-friction surface may include a coating applied to the inner surface of the lead-out port 80a, or a friction reducing member that defines the inner surface of the lead-out port 80a, for example. As an example, the low-friction surface may be made of a POM resin.

If the power supply wires <NUM> and the signal wire <NUM> were restrained (not moved) in the lead-out port 80a of the cowling <NUM>, the power supply wires <NUM> and the signal wire <NUM> would receive a large bending stress at the time of steering the duct <NUM>, and it is not preferable.

As shown in <FIG>, the power supply wires <NUM> supply power from the power source P mounted on the hull 101a to each portion of the marine propulsion unit <NUM> such as the controller <NUM>, the stator <NUM>, or the electric motor <NUM>. The power supply wires <NUM> are more vulnerable to torsion and easier to bend than the signal wire <NUM>. The power supply wires <NUM> include two wires of a positive electrode wire and a negative electrode wire.

The signal wire <NUM> transmits a drive signal from the operator S mounted on the hull 101a to the controller <NUM>, for example, in the casing <NUM>. The signal wire <NUM> is harder to bend and more resistant to torsion than the power supply wires <NUM>. The signal wire <NUM> includes one wire. As an example, the signal wire <NUM> includes a cabtyre cable.

The power supply wires <NUM> and the signal wire <NUM> are located outside and along the casing <NUM> so as to pass in front of the steering shaft <NUM> along the rotation direction of the steering shaft <NUM> from the first side (right side) of the casing <NUM> to the second side (left side) of the casing <NUM> in the right-left direction (see <FIG>) in a plan view. Furthermore, the power supply wires <NUM> and the signal wire <NUM> are located on the same path outside the casing <NUM>.

The power supply wires <NUM> and the signal wire <NUM> are introduced from the hull <NUM> a into the cowling <NUM>, pass above the trim-tilt shaft B30, and are led out of the cowling <NUM> from the lead-out port 80a of the cowling <NUM> (bottom plate <NUM>) via the restrainer <NUM> (predetermined position) that restrains the power supply wires <NUM> and the signal wire <NUM>. The power supply wires <NUM> and the signal wire <NUM> led out of the cowling <NUM> from the lead-out port 80a are located outside (below) the cowling <NUM> and along the casing <NUM> so as to pass in front of the casing <NUM>.

Specifically, the power supply wires <NUM> and the signal wire <NUM> are curved along the curved surface <NUM> on the front side of the casing <NUM>. Furthermore, the power supply wires <NUM> and the signal wire <NUM> are placed in a substantially elliptical shape along the substantially arcuate curved surface <NUM>.

As shown in <FIG> and <FIG>, first portions 92a of the power supply wires <NUM> and the signal wire <NUM> are located on the first side (right side) in the right-left direction, and the second portions 92b of the power supply wires <NUM> and the signal wire <NUM> introduced into the casing <NUM> are located on the second side (left side) in the right-left direction. That is, the first portions 92a refer to wire portions located on the first side (right side) of the casing <NUM> in the right-left direction. The second portions 92b refer to wire portions located on the second side (left side) of the casing <NUM> in the right-left direction. Both the first portions 92a and the second portions 92b refer to wire portions exposed below the cowling <NUM> and outside the casing <NUM>.

The power supply wires <NUM> and the signal wire <NUM> are located along the casing <NUM> while being inclined so as to be located more forward toward the lower side. That is, the power supply wires <NUM> and the signal wire <NUM> are obliquely inclined such that the forward portions thereof are lowered, as viewed in the right-left direction.

The second portions 92b of the power supply wires <NUM> and the signal wire <NUM> are introduced into the introduction hole <NUM> of the casing <NUM> obliquely from the lower front side toward the upper rear side, as viewed in the right-left direction (from the left). That is, the power supply wires <NUM> and the signal wire <NUM> are introduced into the introduction hole <NUM> while maintaining the wiring directions thereof along the casing <NUM> so as to not receive a large bending stress in the introduction hole <NUM>.

The power supply wires <NUM> and the signal wire <NUM> are located along the streamlined casing <NUM> such that lower ends <NUM> thereof are submerged in water. Furthermore, the lower ends <NUM> are located above the duct <NUM>. That is, the power supply wires <NUM> and the signal wire <NUM> are located at heights at which the same do not get caught in the propeller <NUM> and do not obstruct the flow of water generated by the propeller <NUM>.

As described above, the power supply wires <NUM> and the signal wire <NUM> are moved in the forward-rearward direction inside the lead-out port 80a along the lead-out port 80a of the cowling <NUM> as the casing <NUM> is rotated by the steering <NUM>.

According to the various preferred embodiments described above, the following advantageous effects are achieved.

According to a preferred embodiment, the power supply wires <NUM> and the signal wire <NUM> are located outside and along the casing <NUM> so as to pass in front of the steering shaft <NUM> along the rotation (steering) direction of the steering shaft <NUM> from the first side of the casing <NUM> to the second side of the casing <NUM> in the right-left direction in the plan view. Accordingly, the power supply wires <NUM> and the signal wire <NUM> are located so as to be wound around the steering shaft <NUM> in an arcuate shape having a relatively small curvature (an arcuate shape having a large radius) along the casing <NUM>. Furthermore, the power supply wires <NUM> and the signal wire <NUM> are located along the rotation direction of the steering shaft <NUM> such that when the duct <NUM> (casing <NUM>) is steered about the steering shaft <NUM>, the duct <NUM> (casing <NUM>) is steered while a state in which the power supply wires <NUM> and the signal wire <NUM> are wound in an arcuate shape having a relatively small curvature (an arcuate shape having a large radius) along the casing <NUM> is maintained. Therefore, large torsion (deformation) of the power supply wires <NUM> and the signal wire <NUM> is significantly reduced or prevented during steering of the duct <NUM> (casing <NUM>), and thus a constraint on the steering angle of the duct <NUM> (casing <NUM>) is significantly reduced or prevented. Furthermore, the power supply wires <NUM> and the signal wire <NUM> are located along the casing <NUM> such that spaces to provide the power supply wires <NUM> and the signal wire <NUM> are relatively reduced.

According to a preferred embodiment, the power supply wires <NUM> and the signal wire <NUM> are located along the casing <NUM> so as to pass in front of the casing <NUM>. Accordingly, using the front surface of the casing <NUM>, the power supply wires <NUM> and the signal wire <NUM> are easily located so as to be wound around the steering shaft <NUM> in an arcuate shape having a relatively small curvature along the casing <NUM>.

According to a preferred embodiment, the first portions 92a of the power supply wires <NUM> and the signal wire <NUM> are located on the first side in the right-left direction, and the second portions 92b of the power supply wires <NUM> and the signal wire <NUM> introduced into the casing <NUM> are located on the second side in the right-left direction. Accordingly, as compared with a case in which the power supply wires <NUM> and the signal wire <NUM> are located on only one side in the right-left direction, the power supply wires <NUM> and the signal wire <NUM> have a larger arcuate shape (longer path length). Therefore, when the duct <NUM> is steered about the steering shaft <NUM>, the duct <NUM> is steered while a state in which the power supply wires <NUM> and the signal wire <NUM> are wound in an arcuate shape having a relatively small curvature (an arcuate shape having a large radius) along the casing <NUM> in a larger range is maintained. Consequently, large torsion (deformation) of the power supply wires <NUM> and the signal wire <NUM> is further significantly reduced or prevented during steering of the duct <NUM>, and thus a constraint on the steering angle of the duct <NUM> is further significantly reduced or prevented.

According to a preferred embodiment, the casing <NUM> includes, on the second side in the right-left direction, the introduction hole <NUM> to allow the second portions 92b to be introduced into the casing <NUM> therethrough, and the second portions 92b are introduced into the introduction hole <NUM> obliquely from the lower front side toward the upper rear side, as viewed in the right-left direction. Accordingly, the power supply wires <NUM> and the signal wire <NUM> that hang down due to gravity are introduced from below, and thus action of large torsional and bending stresses on the power supply wires <NUM> and the signal wire <NUM> is further significantly reduced or prevented.

According to a preferred embodiment, the power supply wires <NUM> are more vulnerable to torsion and easier to bend than the signal wire <NUM>, and the signal wire <NUM> is harder to bend and more resistant to torsion than the power supply wires <NUM>. Accordingly, even when the power supply wires <NUM> that are relatively vulnerable to torsion and the signal wire <NUM> that is relatively hard to bend are used, action of large torsional and bending stresses on the power supply wires <NUM> and the signal wire <NUM> is significantly reduced or prevented. Therefore, the steerable marine propulsion unit <NUM> is reliably wired.

According to a preferred embodiment, the casing <NUM> includes the curved surface <NUM> that protrudes forward in the plan view, and the power supply wires <NUM> and the signal wire <NUM> are curved along the curved surface <NUM>. Accordingly, the power supply wires <NUM> and the signal wire <NUM> are located along the curved surface <NUM>, and thus when the duct <NUM> is steered about the steering shaft <NUM>, the duct <NUM> is steered while a state in which the power supply wires <NUM> and the signal wire <NUM> are curved more smoothly and are wound in an arcuate shape having a relatively small curvature (an arcuate shape having a large radius) along the casing <NUM> is maintained. Therefore, large torsion (deformation) of the power supply wires <NUM> and the signal wire <NUM> is further significantly reduced or prevented during steering of the duct <NUM>. Thus, action of large torsional and bending stresses on the power supply wires <NUM> and the signal wire <NUM> is further significantly reduced or prevented, and thus a constraint on the steering angle of the duct <NUM> is further significantly reduced or prevented.

According to a preferred embodiment, the curved surface <NUM> has a substantially arcuate shape that protrudes forward in the plan view, and the power supply wires <NUM> and the signal wire <NUM> are placed in a substantially elliptical shape along the substantially arcuate curved surface <NUM>. Note that the substantially arcuate shape includes a precise arcuate shape and shapes similar to the arcuate shape. Furthermore, the substantially elliptical shape includes a precise elliptical shape and shapes similar to the elliptical shape. Accordingly, the power supply wires <NUM> and the signal wire <NUM> are easily placed in a substantially elliptical shape along the curved surface <NUM>, and thus the power supply wires <NUM> and the signal wire <NUM> are placed along the casing <NUM> in a larger range as compared with a case in which the power supply wires <NUM> and the signal wire <NUM> are placed in a circular shape. Therefore, action of large torsional and bending stresses on the power supply wires <NUM> and the signal wire <NUM> is further significantly reduced or prevented.

According to a preferred embodiment, the casing <NUM> has a streamlined shape with the rotation axis direction of the propeller <NUM> as the longitudinal direction, and the power supply wires <NUM> and the signal wire <NUM> are located along the streamlined casing <NUM> such that the lower ends <NUM> thereof are submerged in water. Accordingly, using up to a region in which the power supply wires <NUM> and the signal wire <NUM> are submerged in water as spaces to provide the power supply wires <NUM> and the signal wire <NUM>, the power supply wires <NUM> and the signal wire <NUM> are located along the casing <NUM>, and thus entanglement of foreign matter with the power supply wires <NUM> and the signal wire <NUM> is significantly reduced or prevented.

According to a preferred embodiment, the lower ends <NUM> of the power supply wires <NUM> and the signal wire <NUM> are located above the duct <NUM>. Accordingly, obstruction of the power supply wires <NUM> and the signal wire <NUM> to the flow of water generated by the propeller <NUM> installed in the duct <NUM> is prevented.

According to a preferred embodiment, the power supply wires <NUM> and the signal wire <NUM> are located along the casing <NUM> while being inclined so as to be located more forward toward the lower side. Accordingly, the power supply wires <NUM> and the signal wire <NUM> are located along the casing <NUM> in a larger range as compared with a case in which the power supply wires <NUM> and the signal wire <NUM> are located only in a substantially horizontal direction or a substantially vertical direction. Therefore, action of large torsional and bending stresses on the power supply wires <NUM> and the signal wire <NUM> is further significantly reduced or prevented.

According to a preferred embodiment, the casing <NUM> includes, on the second side in the right-left direction, the introduction hole <NUM> to allow the power supply wires <NUM> and the signal wire <NUM> to be introduced into the casing <NUM> therethrough, the marine propulsion unit <NUM> further includes, above the casing <NUM>, the cowling <NUM> to allow the power supply wires <NUM> and the signal wire <NUM> to pass therethrough, and the cowling <NUM> includes, on the side opposite to the introduction hole <NUM> in the right-left direction, the lead-out port 80a to lead the power supply wires <NUM> and the signal wire <NUM> from within the cowling <NUM> to the first side of the casing <NUM> in the right-left direction. Accordingly, the power supply wires <NUM> and the signal wire <NUM> are led downward from the lead-out port 80a located on the side opposite to the introduction hole <NUM> in the right-left direction and above the introduction hole <NUM>, and thus the power supply wires <NUM> and the signal wire <NUM> are easily placed along the casing <NUM> while hanging down due to gravity.

According to a preferred embodiment, the lead-out port 80a has an elongated shape that extends in the forward-rearward direction, and the power supply wires <NUM> and the signal wire <NUM> are moved in the forward-rearward direction inside the lead-out port 80a along the lead-out port 80a as the casing <NUM> is rotated. Accordingly, as compared with a case in which the power supply wires <NUM> and the signal wire <NUM> are completely constrained by the lead-out port 80a, torsional and bending stresses applied to the power supply wires <NUM> and the signal wire <NUM> during steering of the duct <NUM> are reduced, and a constraint on the steering angle of the duct <NUM> is further significantly reduced or prevented.

According to a preferred embodiment, the marine propulsion unit <NUM> further includes the restrainer <NUM> to bundle the power supply wires <NUM> and the signal wire <NUM> at the predetermined position inside the cowling <NUM> and allow the power supply wires <NUM> and the signal wire <NUM> to pass through the predetermined position. Accordingly, the power supply wires <NUM> and the signal wire <NUM> are constrained at a position spaced relatively apart from the casing <NUM> to be steered. That is, the power supply wires <NUM> and the signal wire <NUM> are constrained at a position at which the influence of steering is relatively small. Therefore, action of large torsional and bending stresses on the power supply wires <NUM> and the signal wire <NUM> is further significantly reduced or prevented.

According to a preferred embodiment, the marine propulsion unit <NUM> further includes the trim-tilt mechanism <NUM> to rotate the marine propulsion unit main body 100a in the upward-downward direction, and the restrainer <NUM> is freely rotatable about the axis that extends in the right-left direction when the marine propulsion unit main body 100a is rotated in the upward-downward direction by the trim-tilt mechanism <NUM>. Accordingly, when the marine propulsion unit main body 100a is rotated in the upward-downward direction by the trim-tilt mechanism <NUM>, the restrainer <NUM> is rotated to reduce torsional and bending stresses applied to the power supply wires <NUM> and the signal wire <NUM>.

According to a preferred embodiment, the predetermined position is located closer to the casing <NUM> than the trim-tilt shaft B30. Accordingly, the power supply wires <NUM> and the signal wire <NUM> are constrained at a position spaced apart by an appropriate distance not too far from the casing <NUM>. Thus, large movement of the power supply wires <NUM> and the signal wire <NUM> located along the casing <NUM> is prevented during steering of the duct <NUM>.

The preferred embodiments described above are illustrative for present teaching but the present teaching also relates to modifications of the preferred embodiments.

For example, while the marine propulsion unit preferably includes the trim-tilt mechanism in preferred embodiments described above, the present teaching is not restricted to this. In the present teaching, the marine propulsion unit may not include the trim-tilt mechanism.

While the marine propulsion unit preferably includes only one signal wire in preferred embodiments described above, the present teaching is not restricted to this. In the present teaching, the marine propulsion unit may alternatively include a plurality of signal wires.

While the power supply wires and the signal wire are preferably introduced into the casing from the introduction hole on the left side of the casing of the marine propulsion unit in preferred embodiments described above, the present teaching is not restricted to this. In the present teaching, the introduction hole may alternatively be provided on the right side of the casing of the marine propulsion unit, and the power supply wires and the signal wire may alternatively be introduced into the casing from the introduction hole on the right side. In such a case, the lead-out port is provided on the left side of the cowling.

While the introduction hole is preferably provided on the curved surface of the casing in preferred embodiments described above, the present teaching is not restricted to this. In the present teaching, the introduction hole may alternatively be provided in a portion rearward of the curved surface of the casing.

While the lower ends of the power supply wires and the signal wire of the marine propulsion unit are preferably submerged in water in preferred embodiments described above, the present teaching is not restricted to this. In the present teaching, the lower ends of the power supply wires and the signal wire may alternatively be covered with a cover so as to not be submerged in water.

While the casing of the marine propulsion unit preferably has a streamlined shape in preferred embodiments described above, the present teaching is not restricted to this. In the present teaching, the casing of the marine propulsion unit may alternatively have a shape other than a streamlined shape such as an elliptical shape.

While the predetermined position at which the power supply wires and the signal wire are bundled by the restrainer is preferably located closer to the casing than the trim-tilt shaft in preferred embodiments described above, the present teaching is not restricted to this. In the present teaching, the predetermined position at which the power supply wires and the signal wire are bundled by the restrainer may alternatively be located in the trim-tilt shaft or on the hull side relative to the trim-tilt shaft.

While the restrainer preferably includes the cylindrical portion and the annular restraining portion in preferred embodiments described above, the present teaching is not restricted to this. In the present teaching, the restrainer may alternatively include a string-shaped member, for example.

Claim 1:
A marine propulsion unit (<NUM>) comprising:
a duct (<NUM>) including a stator (<NUM>);
a propeller (<NUM>) including a rim (<NUM>) including a rotor (40a) facing the stator (<NUM>), and a blade (<NUM>) provided radially inwardly of the rim (<NUM>);
a steering shaft (<NUM>) extending in an upward-downward direction so as to rotatably support the duct (<NUM>);
a casing (<NUM>) together with the duct (<NUM>) being rotated by the steering shaft (<NUM>), provided above the duct (<NUM>), and housing the steering shaft (<NUM>) and a controller (<NUM>) programmed to control driving of the propeller (<NUM>);
a power supply wire (<NUM>) configured to supply power from a power source (P) to the stator (<NUM>); and
a signal wire (<NUM>) configured to transmit a drive signal to the controller (<NUM>);
characterized in that the casing (<NUM>) includes, on a second side in the right-left direction, an introduction hole (<NUM>) configured to allow the power supply wire (<NUM>) and the signal wire (<NUM>) to be introduced into the casing (<NUM>) therethrough;
the marine propulsion unit further includes, above the casing (<NUM>), a cowling (<NUM>) configured to allow the power supply wire (<NUM>) and the signal wire (<NUM>) to pass therethrough; and
the cowling (<NUM>) includes, on a side opposite to the introduction hole (<NUM>) in the right-left direction, a lead-out port (80a) configured to lead the power supply wire (<NUM>) and the signal wire (<NUM>) from within the cowling (<NUM>) to a first side of the casing (<NUM>) in the right-left direction, and the power supply wire (<NUM>) and the signal wire (<NUM>) are located outside and along the casing (<NUM>) so as to pass in front of the steering shaft (<NUM>) along a rotation direction of the steering shaft (<NUM>) from the first side of the casing (<NUM>) to the second side of the casing (<NUM>) in the right-left direction in a plan view.