WATERCRAFT STEERING DEVICE AND ELECTRIC ASSIST DEVICE

Abstract

A watercraft steering device includes: a steering rotatably provided on a hull; a helm mechanism configured to convert a rotational operation of the steering into a linear motion and adjust a traveling direction of the hull; and an electric assist device configured to generate a torque depending on a rotation amount of the steering. The electric assist device is couplable to the helm mechanism, and the electric assist device includes: a coupling shaft portion that is coupled to a helm shaft portion that is a rotation shaft of the helm mechanism; an electric motor that generates a torque by being energized and transmits the generated torque to the coupling shaft portion; and a control device that controls the electric motor to generate a predetermined torque based on a magnitude of the torque generated by rotation of the steering.

Description

CROSS-REFERENCE RELATED APPLICATIONS

This application claims the benefit of priority under 35 U.S.C. § 119 to Japanese Patent Application No. 2023-111950 filed on Jul. 7, 2023, the content of which is incorporated herein by reference.

FIELD OF THE INVENTION

The present disclosure relates to a watercraft steering device and an electric assist device.

BACKGROUND OF THE INVENTION

Many watercrafts are equipped with a watercraft steering device for steering a traveling direction of a hull.

Japanese Unexamined Patent Application Publication No. 2005-231383 (hereinafter, referred to as Patent Literature 1) discloses a technique as the related art relating to a watercraft steering device.

The watercraft steering device disclosed in Patent Literature 1 includes a steering, a helm mechanism for adjusting a traveling direction of a hull in accordance with a rotational operation of the steering, and an electric assist device capable of generating a torque in accordance with the rotational operation of the steering.

By providing the electric assist device, operability can be improved, for example, a force required for the operation of the steering can be reduced, a slight operation of the steering at the time of straight traveling can be made unnecessary, and the force required for the rotational operation in a left-right direction can be equalized.

For example, it is conceivable to replace a watercraft steering device having no electric assist device in order to apply a torque by an electric motor. In this case, since replacement of the watercraft steering device increases the cost, it is preferable that only the electric assist device can be attached later.

The present disclosure relates to an electric assist device that can be attached later and/or a watercraft steering device to which the electric assist device is attached.

SUMMARY OF THE INVENTION

A first aspect of the present disclosure relates to a watercraft steering device including: a steering rotatably provided on a hull; a helm mechanism configured to convert a rotational operation of the steering into a linear motion and adjust a traveling direction of the hull; and an electric assist device configured to generate a torque depending on a rotation amount of the steering. The electric assist device is couplable to the helm mechanism, and the electric assist device includes: a coupling shaft portion that is coupled to a helm shaft portion that is a rotation shaft of the helm mechanism; an electric motor that generates a torque by being energized and transmits the generated torque to the coupling shaft portion; and a control device that controls the electric motor to generate a predetermined torque based on a magnitude of the torque generated by rotation of the steering.

A second aspect of the present disclosure relates to an electric assist device. The electric assist device is couplable to a helm mechanism configured to adjust a traveling direction of a hull, the electric assist device is configured to generate a torque according to a rotation amount of a steering, and the electric assist device includes: a coupling shaft portion configured to transmit the torque to a helm shaft portion that is a rotation shaft of the helm mechanism; an electric motor configured to generate a torque by being energized and transmit the torque to the coupling shaft portion; and a control device configured to control the electric motor to generate a predetermined torque based on a magnitude of the torque generated by rotation of the steering.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the present disclosure will be described in detail based on the following figures, wherein:

FIG. 1 is a plan view of a watercraft on which a watercraft steering device according to an embodiment is mounted;

FIG. 2 is a block diagram of the watercraft steering device shown in FIG. 1;

FIG. 3 is a sectional view of a main part of the watercraft steering device shown in FIG. 1 taken along an axis;

FIG. 4 is an enlarged view of a main part of FIG. 3;

FIG. 5 is a cross-sectional view taken along a line 5-5 of FIG. 4;

FIG. 6A is a view showing the watercraft steering device in a state before an electric assist device is attached;

FIG. 6B is a view showing a removing step of removing the watercraft steering device shown in FIG. 6A;

FIG. 6C is a view showing an assist device attaching step of attaching the electric assist device to a hull;

FIG. 6D is a view showing a stay for attaching a helm mechanism to the hull;

FIG. 6E is a view showing a helm mechanism coupling step of attaching the helm mechanism to the hull and coupling the helm mechanism to the electric assist device; and

FIG. 6F is a view showing a steering coupling step of coupling a steering to the electric assist device.

DETAILED DESCRIPTION OF THE INVENTION

An embodiment of the present disclosure will be described below with reference to the accompanying drawings. In the following description, left and right refer to the left and right with respect to an occupant of a watercraft, and front and rear refer to the front and the rear with respect to a traveling direction of the watercraft.

In the drawing, Fr denotes the front, Rr denotes the rear, Le denotes the left as viewed from the occupant, Ri denotes the right as viewed from the occupant, Up denotes the up, and Dn denotes the down. The embodiment shown in the attached drawings is an example of the present disclosure, and the present disclosure is not limited to the embodiment.

Embodiment

Reference is made to FIG. 1. A watercraft 10 is configured to adjust a traveling direction of a hull 11 by changing a direction of an outboard motor 13 attached to a rear portion of the hull 11 when an occupant operates a watercraft steering device 20 (hereinafter, referred to as “steering device 20”) provided in the hull 11.

As the hull 11 and the outboard motor 13, well-known ones can be used. In particular, as the outboard motor 13, one using an internal combustion engine, one using an electric motor, one using both of them, and the like can be freely selected. Hereinafter, the steering device 20 will be described in detail.

Reference is made to FIGS. 2 and 3. The steering device 20 includes a steering 21 rotatably provided on the hull 11, an electric assist device 30 (hereinafter, referred to as an “assist device 30”) that assists a rotational operation of the steering 21, a helm mechanism 90 that converts a torque generated by the steering 21 and the assist device 30 into a linear motion, and a battery 24 that can energize the assist device 30.

The battery 24 does not necessarily need to be provided only for energizing the assist device 30. It is also possible to divert what is already provided in the watercraft 10 for other purposes.

The steering device 20 is configured such that the steering 21 is directly connected to the helm mechanism 90, and the assist device 30 can be added later. That is, well-known ones can be used as the steering 21 and the helm mechanism 90.

In particular, reference is made to FIG. 3. The steering 21 includes a steering shaft portion 21a serving as a rotation shaft provided on an axis CL, a wheel 21b that is a wheel-shaped member fixed to one end of the steering shaft portion 21a and is rotated by an occupant, and a retaining member 21c that prevents the wheel 21b from coming off the steering shaft portion 21a.

The other end of the steering shaft portion 21a is formed in a female spline shape. The other end of the steering shaft portion 21a may be formed in a male spline shape.

Reference is made to FIG. 4. The assist device 30 includes a housing 50 fixed to the hull 11, a coupling shaft portion 32 rotatably supported by the housing 50 and coupling the steering 21 and the helm mechanism 90 to each other, an electric motor 70 provided on an outer periphery of the coupling shaft portion 32 and capable of generating a torque assisting the rotational operation of the steering 21, a speed reducer 80 that decelerates the torque generated by the electric motor 70 and transmits the decelerated torque to the coupling shaft portion 32, a torque sensor 35 provided along an outer peripheral surface of the steering shaft portion 21a and detecting a rotational torque of the steering shaft portion 21a, and a control device 36 that energizes the electric motor 70 based on information from the torque sensor 35 and the like.

When the steering shaft portion 21a is not coupled to the coupling shaft portion 32, a steering device of a steer-by-wire type may be used.

Reference is made to FIG. 2. The assist device 30 further includes a position sensor 41 capable of detecting a position of the watercraft 10, an automated driving switch 42 for switching on and off an automated driving mode in which automated driving is performed, a reaction force application switch 43 for switching on and off a reaction force application mode in which a reaction force is generated in response to the rotational operation of the steering 21, and an angle sensor 45 integrally provided in the motor 70.

Reference is made to FIG. 4. The housing 50 includes a bottomed tubular housing bottom portion 51 that is partially inserted into the hull 11, a housing lid portion 52 that is provided to close one end of the housing bottom portion 51, a substantially tubular housing tube portion 53 that is attached to the housing lid portion 52, and a sensor holding portion 54 that closes one end of the housing tube portion 53 and holds the torque sensor 35.

The housing bottom portion 51 is provided with a seal 61 for preventing dust from entering the housing 50, and bearings 62 and 67 for rotatably supporting the coupling shaft portion 32.

The housing lid portion 52 is provided with the bearing 62 and a bearing 63 that rotatably supports the coupling shaft portion 32.

The housing tube portion 53 is fastened to the housing lid portion 52 via a fastening member 57.

The sensor holding portion 54 is provided with bearings 64 and 65 that rotatably hold the steering shaft portion 21a. The bearings 64 and 65 are provided so as to sandwich the torque sensor 35. An end portion of the sensor holding portion 54 is provided with a seal 66 for preventing dust from entering the housing 50.

The coupling shaft portion 32 includes a steering coupling portion 32a formed in a male spline shape so as to mesh with the steering shaft portion 21a, and a helm coupling portion 32b formed in a female spline shape so as to mesh with the helm mechanism 90.

The steering coupling portion 32a may be formed in a female spline shape according to a shape of an end portion of the steering shaft portion 21a. Similarly, the helm coupling portion 32b may be formed in a male spline shape according to the shape of a helm shaft portion 91a.

For example, radial ball bearings are used as the bearings 62 to 65 and 67.

Reference is also made to FIG. 5. The electric motor 70 may be, for example, a coreless motor. The electric motor 70 is provided outside the housing bottom portion 51 and is fastened to the housing bottom portion 51. A rotation shaft 70a of the electric motor 70 has a distal end formed in a female spline shape and is coupled to the speed reducer 80. The amount of power supplied to the electric motor 70 is controlled by the control device 36.

The speed reducer 80 is a worm gear speed reducer and is housed in the housing bottom portion 51. The speed reducer 80 includes a worm 81 coupled to the rotation shaft 70a of the electric motor 70 and rotatable together with the rotation shaft 70a, and a worm wheel 84 meshing with the worm 81 and provided on the coupling shaft portion 32.

The worm 81 is rotatably supported by bearings 86 and 87 fixed to the housing bottom portion 51. Further, an end portion of the worm 81 is formed into a male spline shape and is coupled to the rotation shaft 70a of the electric motor 70.

When the electric motor 70 is energized and the rotation shaft 70a rotates, the worm 81 rotates together with the rotation shaft 70a. As the worm 81 rotates, the worm wheel 84 meshing with the worm 81 rotates about the axis CL. Since the worm wheel 84 is fixed to the coupling shaft portion 32, a torque of the worm wheel 84 is transmitted to the coupling shaft portion 32. That is, the torque generated by the electric motor 70 is decelerated and transmitted to the coupling shaft portion 32.

For example, a magnetostrictive torque sensor can be used as the torque sensor 35.

The control device 36 is composed of, for example, a printed circuit board housed and fixed in the housing tube portion 53. The control device 36 includes, for example, a CPU, a ROM in which programs executed by the CPU, various data, and the like are stored, a RAM used as a working memory of the CPU, and an EEPROM that is a nonvolatile memory.

Reference is made to FIG. 2. A global positioning system (GPS) can be used as the position sensor 41. Position information detected by the position sensor 41 is transmitted to the control device 36 as an electric signal. The control device 36 can also calculate the speed of the watercraft 10 from the amount of change in the position information.

The automated driving switch 42 may be provided with a canceling function of switching off the automated driving mode when the steering 21 is operated in a state in which the automated driving mode is turned on.

When the automated driving switch 42 is turned on to set the automated driving mode, the watercraft can be made to travel straight by the assist device 30. For example, a lateral force may be applied to the hull 11 in the traveling direction by waves. The control device 36 detects that the traveling direction of the watercraft 10 deviates from the initially set straight traveling direction based on the information from the position sensor 41, and operates the electric motor 70 to return to the initially set straight traveling direction. In addition, the control device 36 can also operate the electric motor 70 such that the watercraft 10 heads toward a predetermined place.

When the reaction force application mode is turned on, the control device 36 can change output of the electric motor 70 so that a reaction force applied to the steering 21 increases as the speed increases and the reaction force applied to the steering 21 decreases as the speed decreases. Further, due to an influence of the helm mechanism 90, when the steering 21 is rotated, a force required for the operation may be different between a clockwise direction and a counterclockwise direction. When the reaction force application mode is turned on, the control device 36 can change the output of the electric motor 70 so that the force required for the operation is same in the clockwise direction and the counterclockwise direction. By adjusting the reaction force according to the speed and/or adjusting the reaction force according to a rotation direction of the steering 21, the feeling at the time of steering can be improved. When the person steering the watercraft releases his/her hand from the steering 21 and brings the steering 21 into a free state, the control device 36 adjusts an assist torque in the clockwise direction and the counterclockwise direction so that the steering 21 returns to a center of a rotation range. This improves the feeling when a person steers the watercraft.

When the automated driving switch 42 is turned on in a state in which the reaction force application switch 43 is turned on, it is also possible to apply a canceling function of switching off the reaction force application mode.

Information detected by the angle sensor 45 is transmitted to the control device 36 and can be converted into information on a direction (angle) in which the hull 11 (see FIG. 1) faces.

The control device 36 controls the amount of power supplied to the electric motor 70 based on information on a steering state of the steering 21 received from the torque sensor 35, the position information of the watercraft 10 from the position sensor 41 (the information on the speed of the watercraft calculated from the change in the position information), on/off information of the automated driving mode from the automated driving switch 42, on/off information of the reaction force application mode from the reaction force application switch 43, and the information detected by the angle sensor 45.

Reference is made to FIG. 1. The helm mechanism 90 may be a helm mechanism of the related art. The helm mechanism 90 includes a hydraulic helm 91 that is coupled to the assist device 30 and sends oil according to the torque of the coupling shaft portion 32 (see FIG. 4), two hoses 92 and 93 through which the oil sent from the hydraulic helm 91 flows, a tubular cylinder 94 to which distal ends of the hoses 92 and 93 are coupled and into which the sent oil flows, a piston rod 96 extending from a piston incorporated in the cylinder 94, and a rod-shaped link 97 that connects the piston rod 96 and the outboard motor 13 and can displace the direction of the outboard motor 13.

When the steering 21 is rotated in one direction, the hydraulic helm 91 operates in accordance with the rotation of the coupling shaft portion 32 (see FIG. 4). When the hydraulic helm 91 operates, a flow of oil from the hydraulic helm 91 toward the cylinder 94 is generated in the one hose 92. When the oil flows through the cylinder 94, the piston in the cylinder 94 is displaced to the left and right, and the piston rod 96 is also displaced to the left and right.

When the piston rod 96 is displaced, the link 97 is displaced, the direction of the outboard motor 13 is changed, and the traveling direction of the hull 11 is changed. At this time, a flow of oil from the cylinder 94 toward the hydraulic helm 91 is generated in the other hose 93. When the steering 21 is rotated in a direction opposite to the one direction, a flow of oil from the hydraulic helm 91 toward the cylinder 94 is generated in the other hose 93, and the outboard motor 13 can be displaced in the opposite direction.

Reference is made to FIG. 4. The hydraulic helm 91 includes the helm shaft portion 91a that is a rotation shaft. A tapered portion is formed at a distal end of the helm shaft portion 91a so as to be tapered toward the distal end, and a half-moon key is inserted into a groove formed in the tapered portion. An adapter 98 is attached to an outer periphery of the tapered portion. In the adapter 98, a groove is provided on an inner periphery thereof, the half-moon key is inserted into the groove to restrict relative rotation between the adapter and the helm shaft portion 91a, and an outer periphery thereof is formed in a male spline shape. The helm shaft portion 91a is coupled to the coupling shaft portion 32 via the adapter 98.

When the other end of the steering shaft portion 21a is formed in a male spline shape, the distal end of the helm shaft portion 91a is formed in a female spline shape. At this time, the male spline and the female spline are reversed at both ends of the coupling shaft portion 32.

With regard to the steering device 20 described above, an example of an attachment method when the assist device 30 is retrofitted from a state in which the steering 21 is directly connected to the helm mechanism 90 will be described.

Reference is made to FIG. 6A. FIG. 6A shows a steering device 20A in a state before the assist device 30 (see FIG. 6C) is attached. In order to attach the steering device 20 (see FIG. 6F) including the assist device 30 to the hull 11, first, the steering 21 (see FIG. 6F) and the helm mechanism 90 are removed from the hull 11 (removing step).

FIG. 6B shows the hull 11 after the steering 21 and the helm mechanism 90 are removed. Next, as shown in FIG. 6C, the assist device 30 is attached to the hull 11 (assist device attaching step).

Next, as shown in FIG. 6D, a stay 99 is attached to the hydraulic helm 91, and as shown in FIG. 6E, the helm mechanism 90 is coupled to the assist device 30, and the stay 99 is fixed to the hull 11 (helm mechanism coupling step). Then, as shown in FIG. 6F, the steering 21 is coupled to the assist device 30 by attaching the wheel 21b to the steering shaft portion 21a (steering coupling step). Accordingly, the assist device 30 can be retrofitted to the steering device 20.

The steering device 20 described above is summarized below.

Reference is made to FIG. 1. (1) The steering device 20 includes the steering 21 rotatably provided on the hull 11, the helm mechanism 90 configured to convert the rotational operation of the steering 21 into the linear motion and adjust the traveling direction of the hull 11, and the assist device 30 configured to generate a torque depending on a rotation amount of the steering 21.

Reference is made to FIG. 4. The assist device 30 is couplable to the helm mechanism 90, and includes the coupling shaft portion 32 that is coupled to the helm shaft portion 91a, which is the rotation shaft of the helm mechanism 90, the electric motor 70 that generates the torque by being energized and transmits the generated torque to the coupling shaft portion 32, and the control device 36 that controls the electric motor 70 to generate a predetermined torque based on the magnitude of the torque generated by the rotation of the steering 21.

The assist device 30 includes the coupling shaft portion 32 coupled to the helm shaft portion 91a, and transmits the torque generated by the electric motor 70 to the helm mechanism 90 via the coupling shaft portion 32. Since the coupling shaft portion 32 is provided, the assist device 30 can be retrofitted and coupled later to the steering device 20A (see FIG. 6A) that originally does not have the assist device 30. That is, it is possible to provide the electric assist device 30 that can be attached later (namely, retrofitted) and the steering device 10 to which the electric assist device 30 is attached. Further, by retrofitting the electric assist device 30, it is possible to improve the feeling when the steering 21 is steered.

(2) In the first steering device 20 according to (1), the coupling shaft portion 32 includes the steering coupling portion 32a coupled to the steering shaft portion 21a that is the rotation shaft of the steering 21. The steering shaft portion 21a can be easily coupled to the electric assist device 30 by providing the steering coupling portion 32a coupled to the steering shaft portion 21a.

(3) In the second steering device 20 according to (2), the steering coupling portion 32a is provided between the helm mechanism 90 and the steering 21. The entire steering device 10 is compactly disposed in a part of the hull 11.

(4) The steering devices 20 according to any one of (1) to (3) further includes the speed reducer 80 configured to reduce the torque generated by the electric motor 70 and transmit the reduced torque to the coupling shaft portion 32. The speed reducer 80 is a worm gear speed reducer, and includes the worm 81 that rotates as the rotation shaft 70a (see FIG. 5) of the electric motor 70 rotates, and the worm wheel 84 that is provided coaxially with the coupling shaft portion 32 and meshes with the worm 81 to transmit a torque to the coupling shaft portion 32. When the worm gear reducer is used as the speed reducer 80, a large reduction ratio can be obtained by one stage, and the electric assist device 30 having a compact size and a high output can be provided.

(5) The steering device 20 according to any one of (1) to (4) further includes the housing 50 housing the electric motor 70, the speed reducer 80, and the control device 36 and attachable to the hull 11. Since the electric motor 70, the speed reducer 80, and the control device 36 are housed in the single housing 50, an attachment work when the electric assist device 30 is retrofitted can be performed only once, and workability can be improved.

Reference is made to FIG. 2. (6) The steering device 20 according to any one of (1) to (5) further includes the position sensor 41 configured to detect the position of the hull 11 (see FIG. 1), and the control device 36 controls the output of the electric motor 70 based on the position information received by the position sensor 41. The watercraft 10 can be automatedly steered.

In a state in which no torque is applied to the steering 21, the control device 36 may control the electric motor 70 to return the steering 21 to a predetermined position. That is, how the electric motor 70 is controlled by the control device 36 is not limited to the example described in the embodiment. That is, the present disclosure is not limited to the embodiment as long as the functions and effects of the present disclosure are achieved.

Claims

1. A watercraft steering device comprising: a steering rotatably provided on a hull;a helm mechanism configured to convert a rotational operation of the steering into a linear motion and adjust a traveling direction of the hull; andan electric assist device configured to generate a torque depending on a rotation amount of the steering, whereinthe electric assist device is couplable to the helm mechanism, andthe electric assist device includes: a coupling shaft portion that is coupled to a helm shaft portion that is a rotation shaft of the helm mechanism; an electric motor that generates a torque by being energized and transmits the generated torque to the coupling shaft portion; and a control device that controls the electric motor to generate a predetermined torque based on a magnitude of the torque generated by rotation of the steering.

2. The watercraft steering device according to claim 1, wherein the coupling shaft portion includes a steering coupling portion coupled to a steering shaft portion that is a rotation shaft of the steering.

3. The watercraft steering device according to claim 2, wherein the steering coupling portion is provided between the helm mechanism and the steering.

4. The watercraft steering device according to claim 1, further comprising: a speed reducer configured to reduce the torque generated by the electric motor and transmit the reduced torque to the coupling shaft portion, whereinthe speed reducer is a worm gear speed reducer, and includes a worm that rotates as a rotation shaft of the electric motor rotates, and a worm wheel that is provided coaxially with the coupling shaft portion and meshes with the worm to transmit a torque to the coupling shaft portion.

5. The watercraft steering device according to claim 1, further comprising: a housing that houses the electric motor, the speed reducer, and the control device, and is attachable to the hull.

6. The watercraft steering device according to claim 1, further comprising: a position sensor configured to detect a position of the hull, whereinthe control device controls output of the electric motor based on position information received by the position sensor.

7. An electric assist device, wherein the electric assist device is couplable to a helm mechanism configured to adjust a traveling direction of a hull,the electric assist device is configured to generate a torque according to a rotation amount of a steering, andthe electric assist device comprises:a coupling shaft portion configured to transmit the torque to a helm shaft portion that is a rotation shaft of the helm mechanism;an electric motor configured to generate a torque by being energized and transmit the torque to the coupling shaft portion; anda control device configured to control the electric motor to generate a predetermined torque based on a magnitude of the torque generated by rotation of the steering.