阅读说明：本技术 用于船的转向装置 (Steering device for ship ) 是由 竹内太规 吉村恭次 山本康晴 山元达裕 于 2020-10-09 设计创作，主要内容包括：一种用于船(10)的转向装置,包括使舵运动的转向机构(31、71)以及驱动源。转向机构(31、71)具有：壳体,其固定至船体(10a)；输出轴(44),其由壳体可旋转地支撑；第一转换机构,其设置在壳体的内部,并将来自驱动源的动力转换为输出轴(44)的旋转；以及第二转换机构,其设置在壳体的外部,并将输出轴(44)的旋转转换为舵的运动。(A steering device for a ship (10) includes a steering mechanism (31, 71) that moves a rudder, and a drive source. The steering mechanism (31, 71) comprises: a housing fixed to a hull (10 a); an output shaft (44) rotatably supported by the housing; a first conversion mechanism that is provided inside the housing and converts power from the drive source into rotation of an output shaft (44); and a second conversion mechanism that is provided outside the housing and converts the rotation of the output shaft (44) into the movement of the rudder.)

1. Steering device for a vessel (10), characterized in that it comprises:

a steering mechanism (31, 71), the steering mechanism (31, 71) moving a rudder provided at the stern of the ship (10); and

a drive source of the steering mechanism (31, 71), wherein

The steering mechanism (31, 71) comprises: a housing fixed to a hull (10 a); an output shaft (44), the output shaft (44) being rotatably supported by the housing; a first conversion mechanism that is provided inside the housing and converts power from the drive source into rotation of the output shaft (44); and a second conversion mechanism that is provided outside the housing and converts the rotation of the output shaft (44) into the movement of the rudder.

2. The steering device according to claim 1, wherein the first conversion mechanism has: a ball screw shaft (41, 81), the ball screw shaft (41, 81) being rotatably supported inside the housing and rotating with the operation of the drive source; a ball screw nut that is screwed onto the ball screw shaft (41, 81) via a plurality of balls (43, 83), and that is provided with rack teeth (42a, 82a) on an outer circumferential surface along an axial direction; and a sector gear (45, 85), the sector gear (45, 85) being integrally rotatably coupled to the output shaft (44) and meshing with the rack teeth (42a, 82a) of the ball screw nut so as to rock about the output shaft (44) as the ball screw nut moves in the axial direction.

3. A steering arrangement according to claim 1 or 2, characterized in that the drive source is a motor (33).

4. The steering device according to claim 2, wherein:

the drive source is a motor (33); and

the steering device has a speed reducer (32), and the speed reducer (32) reduces the rotation speed of the motor (33) and transmits the reduced rotation to the ball screw shaft (41, 81).

5. The steering device according to claim 2, further comprising a control valve (72) based on an assumption that the drive source is an electric pump (61) that discharges hydraulic fluid, and the ball screw nut is slidably disposed in the housing such that an interior of the housing is divided into two fluid chambers by the ball screw nut, the control valve (72) controls supply and discharge of the hydraulic fluid to and from the two fluid chambers, wherein by selectively supplying the hydraulic fluid discharged from the electric pump (61) to one of the two fluid chambers according to manipulation of a steering wheel (14), the control valve (72) moves the ball screw nut as a piston in the axial direction, wherein the steering wheel (14) is manipulated to change the direction of the hull (10 a).

6. Steering device according to any one of claims 1, 2, 4 and 5, characterized in that the rudder is an outboard motor (12), which outboard motor (12) is arranged as a propulsion unit of the ship (10) outside the stern so as to be rotatable about a pivot (22) and also functions as the rudder of the ship (10) by rotating about the pivot (22).

7. Steering device according to any one of claims 1, 2, 4 and 5, characterized in that the rudder is provided on the outside of the stern separately from the propulsion unit of the boat (10) so as to be rotatable about a support shaft (123).

8. The steering arrangement according to any one of claims 1, 2, 4 and 5, characterized in that the power transmission between the rudder and a steering wheel (14) steered to change the direction of the hull (10a) is isolated.

9. The steering device according to any one of claims 1, 2, 4 and 5, characterized in that:

the rudder is coupled to a steering wheel (14) that is steered to change the direction of the hull (10 a); and

the drive source generates an assist force that assists the rudder movement by the steering of the steering wheel (14).

Technical Field

The present invention relates to a steering device for a ship.

Background

Examples of the existing steering device for a ship include the steering device described in japanese patent application publication No.2010-143413(JP2010-143413 a). The steering device has a steering mechanism (turning mechanism) and a controller. The steering mechanism rocks the outboard motor, which is supported at the stern of the hull so as to be rotatable about a steering shaft, leftward or rightward with respect to the advancing direction of the hull. The controller controls the operation of the steering mechanism according to the manipulation of a steering wheel provided in the hull cabin.

The steering mechanism includes a pair of left and right support members provided at the stern, a ball screw shaft, a ball screw nut, and a steering motor. The ball screw shaft is coupled between the two support members. The ball screw nut is screwed on the ball screw shaft. The steering motor has a housing that rotatably accommodates a ball screw nut, and a stator fixed inside the housing. When a current is applied to the stator, a ball screw nut serving as a rotor rotates.

The housing is provided with a steering arm extending toward the outboard motor. The steering arm is rotatably coupled to a first end of a steering bracket that is coupled to the outboard motor via a coupling pin. The steering bracket is rotatably supported at the second end portion by a steering shaft provided at the stern.

When the ball screw nut is driven to rotate by the steering motor, the ball screw nut moves leftward or rightward along the ball screw shaft integrally with the housing. This causes the steering bracket coupled to the steering arm to rock left or right about the steering shaft. As a result, the outboard motor coupled to the steering bracket turns left or right.

Disclosure of Invention

In order to steer the outboard motor, the steering device of JP2010-143413a moves the housing together with the ball screw nut leftward or rightward along the ball screw shaft. This makes it necessary to secure a space in the hull in which the housing can move. Interfering objects must also be removed from the path of movement of the housing. Therefore, there is room for improvement in efficiency in mounting the steering mechanism on the hull.

The invention provides a steering device for a ship, a steering mechanism of which can be more efficiently mounted on a hull.

A steering apparatus for a ship according to an aspect of the present invention includes a steering mechanism that moves a rudder provided at a stern of the ship and a driving source of the steering mechanism. The steering mechanism includes: a housing fixed to the hull; an output shaft rotatably supported by the housing; a first conversion mechanism that is provided inside the housing and converts power from the drive source into rotation of the output shaft; and a second conversion mechanism that is provided outside the housing and converts the rotation of the output shaft into the movement of the rudder.

There is a configuration of a steering device for a ship in which a housing of a steering mechanism is movably provided in a hull and movement of the housing is utilized to move a rudder. However, adopting such a configuration requires securing a space in the hull in which the housing can move. In this regard, the above-described steering device for a ship moves the rudder of the ship by simply rotating the output shaft of the steering mechanism, and thus, the housing of the steering mechanism is fixed to the hull. Therefore, it is not necessary to secure a space in the hull in which the housing can move. As a result, the steering mechanism can be mounted on the hull more efficiently.

In the above aspect, the first conversion mechanism may have: a ball screw shaft rotatably supported inside the housing and rotating with an operation of the driving source; a ball screw nut that is screwed to the ball screw shaft by a plurality of balls and is provided with rack teeth on an outer circumferential surface along an axial direction; and a sector gear that is integrally rotatably coupled to the output shaft and that meshes with the rack teeth of the ball screw nut so as to rock about the output shaft as the ball screw nut moves in the axial direction.

This configuration can convert power from the drive source into rotation of the output shaft through the ball screw shaft, the ball screw nut, and the sector gear. In the above aspect, the drive source may be a motor. This configuration can satisfy the requirements for the motorization of the steering mechanism.

In the above-described aspect, the drive source may be a motor, and the steering device may have a speed reducer that reduces a rotational speed of the motor and transmits the reduced speed rotation to the ball screw shaft. In this configuration, the torque from the motor is increased according to the reduction gear ratio of the reduction gear, so that a larger torque according to the reduction gear ratio of the reduction gear is transmitted to the ball screw shaft. Therefore, the rudder can be moved more reliably.

In the above-described aspect, the steering device may further include a control valve that controls supply and discharge of the hydraulic fluid to and from the two fluid chambers on the basis of an assumption that the drive source is an electric pump that discharges the hydraulic fluid, and the ball screw nut is slidably provided in a housing, wherein an interior of the housing is divided into the two fluid chambers by the ball screw nut. The control valve moves the ball screw nut as a piston in an axial direction by selectively supplying hydraulic fluid discharged from the electric pump to one of the two fluid chambers according to manipulation of a steering wheel that is manipulated to change a direction of the hull. In this case, the control valve may move the ball screw nut as a piston in the axial direction by selectively supplying the hydraulic fluid discharged from the electric pump to one of the two fluid chambers according to manipulation of the steering wheel that is manipulated to change the direction of the hull.

In this configuration, the hydraulic fluid from the electric pump is selectively supplied to one of the two fluid chambers in accordance with the manipulation of the steering wheel, thereby generating a pressure difference between the two fluid chambers. According to this pressure difference, the ball screw nut as a piston is pressed in the axial direction thereof, and the ball screw nut is moved along the ball screw shaft. This movement of the ball screw nut is converted into rotation of the output shaft by the sector gear.

In the above aspect, the rudder may be an outboard motor that is provided as a propulsion unit of the ship outside the stern so as to be able to pivot and also function as a rudder of the ship by pivoting.

In the above aspect, the rudder may be provided outside the stern separately from the propulsion unit of the ship so as to be rotatable about the support shaft. In the above aspect, it is possible to isolate power transmission between the rudder and the steering wheel that is manipulated to change the direction of the hull.

In the above aspect, the rudder may be coupled to a steering wheel that is manipulated to change the direction of the hull, and the drive source may generate an assist force that assists the movement of the rudder by manipulating the steering wheel.

These aspects allow the steering mechanism to be more efficiently mounted on the hull.

Drawings

Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, wherein like reference numerals denote like elements, and in which:

FIG. 1 is a plan view of a boat having a first embodiment of a marine steering apparatus mounted thereon;

fig. 2 is a side view of the outboard motor in the first embodiment;

fig. 3 is a plan view of the steering actuator in the first embodiment;

fig. 4 is a sectional plan view of the steering actuator in the first embodiment;

fig. 5 is a plan view showing a main portion of the steering actuator in the first embodiment;

FIG. 6 is a plan view of a boat having a second embodiment of marine steering apparatus mounted thereon;

fig. 7 is a sectional plan view of the steering actuator in the second embodiment;

fig. 8 is a schematic view showing the configuration of a power transmission mechanism between the steering wheel and the steering actuator in the second embodiment;

fig. 9 is a plan view showing a main portion of a steering actuator in another embodiment;

fig. 10 is a plan view showing a main portion of a steering actuator in other embodiments; and

fig. 11 is a perspective view showing an inboard motor of a ship in another embodiment.

Detailed Description

First embodiment

A first embodiment of the marine steering apparatus will be described below. As shown in fig. 1, the ship 10 is provided with an outboard motor 12, a steering actuator 13 as a steering device, a steering wheel 14, and a controller 15.

The outboard motor 12 is provided at the stern of the hull 10 a. The outboard motor 12 is one example of a propulsion unit of the boat 10, and has an engine 12a and a propeller 12b driven to rotate by the engine 12 a. The outboard motor 12 can rock left and right with respect to the forward direction of the ship 10. The outboard motor 12 also functions as a rudder for the boat 10 by rocking left and right.

The steering actuator 13 rocks the outboard motor 12 to the left or right with respect to the forward direction of the boat 10. As the outboard motor 12 rocks to the left or right, the heading of the boat 10 changes. The steering wheel 14 is arranged in the cockpit of the vessel 10. The steering wheel 14 is rotatably supported by the hull 10a through a steering shaft 16. The steering shaft 16 is provided with a rotation angle sensor 17. The rotation angle sensor 17 detects the rotation angle of the steering shaft 16 as a steering angle θ, that is, the rotation angle of the steering wheel 14.

The controller 15 controls the operation of the steering actuator 13 according to the steering angle θ detected by the rotation angle sensor 17. The output of the engine 12a is controlled by another controller provided separately from the controller 15.

Next, a coupling structure of the hull 10a and the outboard motor 12 will be described. As shown in fig. 2, the outboard motor 12 has a turning bracket 21, a pivot shaft 22, and a steering bracket 23.

The turning bracket 21 couples the outboard motor 12 to the hull 10 a. The rotating bracket 21 is constituted by a first coupling portion 21a and a second coupling portion 21b, and is L-shaped as a whole. The first coupling portion 21a extends in the fore-and-aft direction (the left-to-right direction in fig. 2) of the hull 10 a. The second coupling portion 21b extends in the up-down direction of the hull 10 a. The first coupling portion 21a is installed between two clamping brackets 24 provided at the stern of the hull 10a (see fig. 1). The steering actuator 13 is mounted on an upper surface of the first coupling portion 21 a. The second coupling portion 21b is provided with a through hole 21c extending in the up-down direction of the hull 10 a.

The pivot shaft 22 forms a rocking center of the outboard motor 12. The pivot shaft 22 is inserted into the through hole 21c of the second coupling portion 21b of the rotating bracket 21. The pivot 22 is able to rotate relative to the turning bracket 21. The upper end of the pivot shaft 22 protrudes from the upper portion of the second coupling portion 21b of the rotating bracket 21. The upper end of the pivot shaft 22 is coupled to the steering actuator 13 through a steering bracket 23. The portion of the pivot shaft 22 between the steering bracket 23 and the turning bracket 21 is fixed to the housing 12c of the outboard motor 12 by a bracket 25. The lower end of the pivot shaft 22 protrudes from the lower portion of the rotating bracket 21. The lower end of the pivot shaft 22 is fixed to the housing 12c of the outboard motor 12 by a bracket 26. Each of the two brackets 25, 26 is fixed to the pivot 22. The rotation of the pivot shaft 22 relative to the brackets 25, 26 is restricted so that the outboard motor 12 can rotate about the pivot shaft 22 relative to the turning bracket 21.

Next, the configuration of the steering actuator 13 will be described in detail. As shown in fig. 3, the steering actuator 13 includes a steering mechanism 31, a reduction gear 32, a motor 33 as a drive source, and a rotation angle sensor 34. As the steering mechanism 31, a so-called Recirculating Ball Steering (RBS) device is used. The motor 33 and the rotation angle sensor 34 are coupled to the steering mechanism 31 through the speed reducer 32.

As shown in fig. 4, the steering mechanism 31 has a housing 40. Inside the housing 40, a ball screw shaft 41, a ball screw nut 42, a plurality of balls 43, a sector shaft 44 as an output shaft, and a sector gear 45 are provided. The ball screw shaft 41 is rotatably supported by the housing 40 through two bearings 46, 47. The ball screw nut 42 is screwed to the ball screw shaft 41 via a ball 43 that can circulate. The ball screw nut 42 has rack teeth 42a provided on an outer circumferential surface in an axial direction thereof. The sector shaft 44 extends in a direction orthogonal to the axis of the ball screw nut 42 (a direction orthogonal to the paper surface of fig. 4). The sector shaft 44 is rotatably supported by the housing 40 through a bearing (not shown). A sector gear 45 is provided on the sector shaft 44 in an integrally rotatable manner. The teeth 45a of the sector gear 45 mesh with the rack teeth 42a of the ball screw nut 42.

As shown in fig. 3, an upper end portion of the sector shaft 44 is exposed to the outside of the housing 40. The lever 48 is fixed at its first end to the upper end of the sector shaft 44. The link 49 is rotatably supported at a first end thereof by a second end of the lever 48. The steering bracket 23 provided on the outboard motor 12 is rotatably supported by a second end of the link 49 at an end thereof on the opposite side to the pivot shaft 22.

As shown in fig. 4, the decelerator 32 has a housing 50. The housing 50 is coupled to the housing 40 of the steering mechanism 31. The housings 40, 50 communicate internally with each other. The motor 33 is mounted on the outside of the housing 50. The output shaft 33a of the motor 33 extends in a direction orthogonal to the axis of the ball screw shaft 41. The output shaft 33a of the motor 33 extends through the peripheral wall of the housing 50 and is inserted into the housing 50. The rotation angle sensor 34 is mounted at a portion of the housing 50 on the opposite side from the steering mechanism 31.

A shaft 51, a worm wheel 52, and a worm 53 are provided in the housing 50. The shaft 51 is rotatably supported by the housing 50 via two bearings 54, 55. The shaft 51 is integrally rotatably coupled at a first end portion (left end in fig. 4) thereof to the ball screw shaft 41. The shaft 51 is rotatably supported at a second end portion (right end in fig. 4) thereof by a housing that accommodates the detection element of the rotation angle sensor 34. The rotation angle sensor 34 detects the rotation angle of the shaft 51. The worm wheel 52 is provided on the shaft 51 so as to be integrally rotatable. The worm 53 is provided on the output shaft 33a of the motor 33 so as to be integrally rotatable. The worm 53 meshes with the worm wheel 52.

Next, the operation of the steering actuator 13 will be described. The controller 15 performs steering control for steering the outboard motor 12 in accordance with the manipulation amount of the steering wheel 14 by controlling the driving of the motor 33. The controller 15 calculates a target value of the steering amount of the outboard motor 12 based on the steering angle θ of the steering wheel 14 detected by the rotation angle sensor 17. Further, the controller 15 calculates a steering amount of the outboard motor 12 based on the rotation angle of the shaft 51 detected by the rotation angle sensor 34. Then, the controller 15 obtains a difference between the target value of the steering amount of the outboard motor 12 and the actual steering amount of the outboard motor 12, and controls the supply of electric power to the motor 33 to cancel the difference. Alternatively, the controller 15 may control the supply of electric power to the motor 33 not based on the steering amount of the outboard motor 12 but based on the rotation angle of the sector shaft 44, which is one of the state variables reflecting the steering amount of the outboard motor 12.

As shown in fig. 4, the rotation of the motor 33 is transmitted to the ball screw shaft 41 through the reduction gear 32. As the ball screw shaft 41 rotates, the ball screw nut 42 moves along the axial direction of the ball screw shaft 41. The sector gear 45 engaged with the rack teeth 42a rocks leftward or rightward about the sector shaft 44 as the ball screw nut 42 moves. As the sector gear 45 swings, the sector shaft 44 rotates in the same direction as the swing direction of the sector gear 45 in accordance with the amount of swing of the sector gear 45.

As shown in fig. 5, the lever 48 rocks to the left or right about the sector shaft 44 as the sector shaft 44 rotates. For example, when the sector shaft 44 rotates in the counterclockwise direction, the lever 48 rotates in the counterclockwise direction about the sector shaft 44. In response, link 49 attempts to rotate in a clockwise direction about the joint with lever 48. As the link 49 rotates in a clockwise direction, the steering bracket 23 rotates in a counterclockwise direction about the pivot 22. Since the pivot shaft 22 is fixed to the steering bracket 23, as the steering bracket 23 rotates in the counterclockwise direction, a torque directed in the counterclockwise direction is applied to the pivot shaft 22. Since the pivot shaft 22 is fixed to the housing 12c of the outboard motor 12, the outboard motor 12 rotates in the counterclockwise direction about the pivot shaft 22 as the pivot shaft 22 rotates in the counterclockwise direction.

When the sector shaft 44 is rotated in the clockwise direction, the steering bracket 23 is rotated about the pivot shaft 22 in the clockwise direction via the sector gear 45, the lever 48, and the link 49 in the same manner as when the sector shaft 44 is rotated in the counterclockwise direction, so that a torque directed in the clockwise direction is applied to the pivot shaft 22. When the pivot shaft 22 rotates in the clockwise direction, the outboard motor 12 rotates in the clockwise direction about the pivot shaft 22.

The ball screw shaft 41, the ball screw nut 42, and the balls 43 constitute a ball screw mechanism. The ball screw mechanisms (41 to 43) and the sector gear 45 constitute a first conversion mechanism that converts power from the motor 33, which is the drive source of the steering actuator 13, into rotation of the sector shaft 44, which is the output shaft. The lever 48 and the link 49 constitute a second conversion mechanism that converts the rotation of the sector shaft 44 as an output shaft into a steering motion of the outboard motor 12.

Advantages of the embodiments

This embodiment may provide the following advantages: (1) the steering mechanism 31 converts the rotation of the motor 33 into the rotation of the sector gear 45, and transmits the rotation of the sector gear 45 as torque to the pivot shaft 22 of the outboard motor 12. There is a conventional configuration in which a housing of a steering mechanism is provided in a hull so as to be movable together with a ball screw nut, and this movement of the housing is used to steer an outboard motor. However, adopting such a configuration requires ensuring a space in the hull in which the housing can move. In this regard, the steering mechanism 31 of the present embodiment steers the outboard motor 12 by simply rotating the fan shaft 44. The housing 40 of the steering mechanism 31 does not need to move relative to the hull 10a and is therefore fixed to the hull 10 a. Therefore, it is not necessary to secure a space in the hull 10a in which the housing 40 of the steering mechanism 31 can move. As a result, the steering mechanism 31 can be mounted on the hull 10a more efficiently.

(2) The rotation of the sector gear 45 is transmitted to the pivot shaft 22, which is the rotation center of the outboard motor 12, through the sector shaft 44, the lever 48, the link 49, and the steering bracket 23. Since the outboard motor 12 rotates about the pivot shaft 22, it is possible to effectively apply torque for turning the outboard motor 12 to the pivot shaft 22. Although a configuration in which the linear motion of the housing of the steering mechanism is converted into the rotational motion of the outboard motor about the pivot shaft as described above is also conceivable, it is possible to reduce the efficiency of torque transmission to the pivot shaft 22 with this configuration, as compared with the steering mechanism 31 with the present embodiment.

(3) The steering actuator 13 adopts a configuration in which the rotation of the sector gear 45 is transmitted to the pivot shaft 22, which is the rotation center of the outboard motor 12, through the sector shaft 44, the lever 48, the link 49, and the steering bracket 23. This configuration involves less wasteful action in the steering mechanism 31 than the aforementioned configuration that converts linear motion of the housing of the steering mechanism into rotational motion of the pivot. Further, this configuration allows the range of movement of the lever 48 and the link 49, which move in conjunction with the sector gear 45, to be set narrower than the range of movement of the housing of the steering mechanism in the case where the aforementioned housing is linearly moved. Since it is not necessary to move the lever 48 and the link 49 greatly, the installation space of the steering mechanism 31 can be set small.

(4) The motor 33 serves as a drive source of the steering mechanism 31. Therefore, the requirement for motorization of the steering actuator 13 can be satisfied. Further, a high response and a stable steering force can be obtained regardless of the speed (low speed to high speed) and the environment (waves and wind) of the ship 10. For example, when a hydraulic pump driven by an engine is used as the drive source of the steering mechanism 31, the discharge amount of the hydraulic pump and thus the steering force applied to the outboard motor 12 may vary depending on the speed and environment of the ship 10.

(5) Since the steering actuator 13 is electrically powered, there is no need to provide a hydraulic line for supplying and discharging hydraulic oil on the hull 10a, unlike when a hydraulic device is used as a drive source of the steering mechanism 31. Therefore, the configuration of the steering actuator 13 can be simplified. Furthermore, eliminating the need for hydraulic lines may save space on the hull 10 a.

(6) The output shaft 33a of the motor 33 is coupled to the ball screw shaft 41 of the steering mechanism 31 through the speed reducer 32. Therefore, the torque from the motor 33 is increased according to the reduction gear ratio of the speed reducer 32, so that a larger torque according to the reduction gear ratio is transmitted to the ball screw shaft 41. With the force thus obtained required to operate the outboard motor 12, the outboard motor 12 can be steered more reliably.

Second embodiment

Next, a second embodiment of the marine steering device will be described. This embodiment differs from the first embodiment in that a hydraulic steering actuator is used instead of the electric steering actuator.

As shown in fig. 6, the boat 10 is provided with an outboard motor 12, a steering wheel 14, a controller 15, and a hydraulic steering actuator 60. The steering actuator 60 has an electric pump 61 and an accumulator tank 62 as drive sources. Further, the steering actuator 60 has a steering mechanism 71 and a control valve 72 provided on the turning bracket 21 at the stern.

The hydraulic fluid is stored in a reservoir tank 62. The reservoir tank 62 is coupled to the electric pump 61 via an inlet pipe 63. The electric pump 61 is coupled to a pump port of the control valve 72 via a discharge pipe 64. The tank port of the control valve 72 is connected to the reservoir tank 62 via the discharge pipe 65.

The controller 15 controls the electric pump 61 based on the steering angle θ detected by the rotation angle sensor 17. As the electric pump 61 is driven, the hydraulic fluid in the reservoir tank 62 is supplied to the control valve 72 via the drain pipe 64. The hydraulic fluid discharged from the control valve 72 is returned to the reservoir tank 62 via the discharge pipe 65.

Next, the configuration of the steering mechanism 71 will be described in detail. As shown in fig. 7, the steering mechanism 71 has a housing 80. The housing 80 is provided therein with a ball screw shaft 81, a ball screw nut 82, a plurality of balls 83, a sector shaft 84, a sector gear 85, and a closing member 86, and the closing member 86 has a cylindrical shape with one end closed.

The ball screw nut 82 is provided in the housing 80 (specifically, a cylindrical portion thereof) so as to be slidable in a direction along the axis of the ball screw nut 82. The ball screw nut 82 has rack teeth 82a provided on an outer peripheral surface in an axial direction thereof.

The closing member 86 is tightly fitted into the first end portion (left end portion in fig. 7) of the ball screw nut 82. The closing member 86 moves integrally with the ball screw nut 82. The ball screw shaft 81 is screwed into the ball screw nut 82 through the balls 83 that can circulate. A first end portion (left end portion in fig. 7) of the ball screw shaft 81 is inserted into the closing member 86. A predetermined gap is left between the first end of the ball screw shaft 81 and the bottom wall of the closing member 86. The ball screw nut 82 is movable relative to the ball screw shaft 81 along the axial direction of the ball screw shaft 81 within the range of the gap between the ball screw shaft 81 and the bottom wall of the closing member 86. A second end portion (right end portion in fig. 7) of the ball screw shaft 81 protrudes from a second end portion (right end portion in fig. 7) of the ball screw nut 82. A second end of the ball screw shaft 81 is coupled to the control valve 72.

The sector shaft 84 extends in a direction orthogonal to the axis of the ball screw nut 82 (a direction orthogonal to the paper surface of fig. 7). The sector shaft 84 is rotatably supported by the housing 80 through a bearing (not shown).

A sector gear 85 is provided on the sector shaft 84 in an integrally rotatable manner. The teeth 85a of the sector gear 85 mesh with the rack teeth 82a of the ball screw nut 82. An upper end portion of the sector shaft 84 is exposed to the outside of the housing 80. The steering bracket 23 is coupled at its end on the opposite side from the pivot shaft 22 to the upper end of the sector shaft 84 through the lever 48 and the link 49 (see fig. 2).

The interior of the housing 80 is divided by the ball screw nut 82 and the closure member 86 into a first fluid chamber 87 and a second fluid chamber 88. The first fluid chamber 87 is located on the side of the control valve 72 with respect to the ball screw nut 82. The second fluid chamber 88 is located on the opposite side of the control valve 72 from the ball screw nut 82.

The first fluid chamber 87 and the second fluid chamber 88 are supplied with hydraulic fluid through the control valve 72. When the hydraulic fluid from the electric pump 61 is selectively supplied to one of the first fluid chamber 87 and the second fluid chamber 88 through the control valve 72, a pressure difference is generated between the first fluid chamber 87 and the second fluid chamber 88. The ball screw nut 82 and the closing member 86 are pressed in their respective axial directions in accordance with the pressure difference, so that the ball screw nut 82 and the closing member 86, which serve as pistons, move along the ball screw shaft 81. As the ball screw nut 82 moves, the sector gear 85 rocks to the left or right about the sector shaft 84. With the rocking of the sector gear 85, the sector shaft 84 rotates in the same direction as the rocking direction of the sector gear 85.

Next, the configuration of the control valve 72 will be described in detail. As shown in fig. 7, the control valve 72 has a housing 90. The housing 90 is coupled to the housing 80 of the steering mechanism 71. Inside the housing 90, a hollow input shaft 91, a torsion bar 92, an inner valve 93, and an outer valve 94 are provided.

The input shaft 91 extends through the housing 90. The input shaft 91 is rotatably supported by the housing 90 via a bearing 95. A first end portion (left end portion in fig. 7) of the input shaft 91 is inserted into a recessed portion 81a provided as an insertion portion at a second end portion (right end portion in fig. 7) of the ball screw shaft 81 so that the input shaft 91 can rotate relative to the ball screw shaft 81. A rotation angle sensor 34 is provided at a second end portion (right end portion in fig. 7) of the input shaft 91.

A torsion bar 92 extends through the input shaft 91. The torsion bar 92 is fixed at a first end portion thereof (left end portion in fig. 7) to a bottom portion of a recess 81a provided at a second end portion (right end portion in fig. 7) of the ball screw shaft 81. The torsion bar 92 is fixed at a second end portion thereof (right end portion in fig. 7) to a second end portion (right end portion in fig. 7) of the input shaft 91.

The internal valve 93 is provided inside the housing 90 and on the outer peripheral portion of the input shaft 91. The outer valve 94 is provided on the inner peripheral portion of the housing 90. The torsion bar 92 twists according to the torque applied to the input shaft 91, and the positional relationship (relative angle) between the inner valve 93 and the outer valve 94 in the rotational direction changes according to this twisting of the torsion bar 92. The control valve 72 switches the flow path of the hydraulic fluid by utilizing such a change in the positional relationship in the rotational direction between the inner valve 93 and the outer valve 94. In addition, the control valve 72 adjusts the flow rate of the hydraulic fluid supplied to the first fluid chamber 87 and the second fluid chamber 88 by forming a restriction (constraint) in accordance with the difference between the rotation angle of the input shaft 91, i.e., the inner valve 93, and the rotation angle (valve operating angle) of the outer valve 94.

The hydraulic fluid supplied from the electric pump 61 via the discharge pipe 64 is distributed to one of the first fluid chamber 87 and the second fluid chamber 88 according to a change in the relative angle between the inner valve 93 and the outer valve 94. When the input shaft 91 is rotated in the clockwise direction as viewed from the axial direction of the input shaft 91, the electric pump 61 and the first fluid chamber 87 communicate with each other. On the other hand, when the input shaft 91 rotates in the counterclockwise direction as viewed from the axial direction of the input shaft 91, the electric pump 61 and the second fluid chamber 88 communicate with each other.

For example, when hydraulic fluid is supplied to the second fluid chamber 88, the ball screw nut 82 and the closing member 86 move toward the first fluid chamber 87 under the pressure of the hydraulic fluid. As the ball screw nut 82 moves, the hydraulic fluid in the first fluid chamber 87 is pushed out of the first fluid chamber 87. The hydraulic fluid pushed out of the first fluid chamber 87 is discharged to the reservoir tank 62 via the discharge pipe 65.

When the hydraulic fluid is supplied to the first fluid chamber 87, the ball screw nut 82 and the closing member 86 move toward the second fluid chamber 88 under the pressure of the hydraulic fluid. As the ball screw nut 82 moves, hydraulic fluid within the second fluid chamber 88 is pushed out of the second fluid chamber 88. The hydraulic fluid pushed out of the second fluid chamber 88 is discharged to the reservoir tank 62 via the discharge pipe 65.

In this way, the supply of the hydraulic fluid into the first fluid chamber 87 and the second fluid chamber 88 or the discharge from the first fluid chamber 87 and the second fluid chamber 88 is controlled in accordance with the torque applied to the input shaft 91, that is, in accordance with the rotation of the input shaft 91. The input shaft 91 rotates in conjunction with the steering of the steering wheel 14. The following configuration is an example of a configuration for transmitting power from the steering wheel 14 to the input shaft 91.

As shown in fig. 8, the steering shaft 16 is provided with a drive pulley 101 so as to be integrally rotatable. An idle pulley 102 is provided to the input shaft 91 of the control valve 72 so as to be integrally rotatable. The drive pulley 101 and the idler pulley 102 are coupled together by two steering cables 103, 104. As the drive pulley 101 rotates, the idle pulley 102 and the input shaft 91 rotate together with the drive pulley 101.

In a state where the first end portions of the two manipulation cables 103, 104 are fixed to the two side surfaces of the drive pulley 101 that face each other in the axial direction of the drive pulley 101, and in a state where the manipulation cables 103, 104 are wound in directions toward each other along spiral grooves provided in the outer circumferential surface of the drive pulley 101, the first end portions of the two manipulation cables 103, 104 are led out in a direction intersecting the axis of the drive pulley 101.

Like the first end portions of the two manipulation cables 103, 104, in a state where the second end portions of the manipulation cables 103, 104 are fixed to both side surfaces of the idler pulley 102 that face each other in the axial direction of the idler pulley 102, and in a state where the manipulation cables 103, 104 are wound in directions toward each other along spiral grooves provided in the outer circumferential surface of the idler pulley 102, the second ends of the manipulation cables 103, 104 are led out in a direction intersecting the axis of the idler pulley 102.

To steer the ship 10, the steering wheel 14 is steered, and the drive pulley 101 is rotated in conjunction with the steering of the steering wheel 14. As the drive pulley 101 rotates, one of the two steering cables 103, 104 wound around the drive pulley 101 is pulled and the other is released. Thus, the rotation of the drive pulley 101 is transmitted to the idle pulley 102. As the idler pulley 102 rotates, the input shaft 91 of the control valve 72 rotates together with the idler pulley 102, and as the input shaft 91 rotates, the sector gear 85 rocks. This rocking motion of the sector gear 85 is transmitted to the pivot shaft 22 through the sector shaft 84, the lever 48, the link 49, and the steering bracket 23, thereby steering the outboard motor 12.

Therefore, the second embodiment can provide the same advantages as those (1) to (3) of the first embodiment. Further, the electric pump 61 functions as a hydraulic pump. Therefore, although it is necessary to provide the hull 10a with hydraulic lines, the second embodiment can provide the same advantages as the advantages (4) of the first embodiment.

Other embodiments

The first and second embodiments may be implemented with the following modifications thereto. In the first embodiment, the controller 15 is provided at an appropriate position in the hull 10a, but alternatively the controller 15 may be provided integrally with the motor 33.

In the first embodiment, a worm reducer having the worm 53 and the worm wheel 52 is used as the reducer 32, but instead of this worm reducer, a belt transmission mechanism may be used. Specifically, as shown in fig. 10, the motor 33 is mounted on the housing 50 of the reduction gear 32 in a posture in which the output shaft 33a thereof is parallel to the shaft 51 of the reduction gear 32. The drive pulley 111 is provided on the output shaft 33a of the motor 33 so as to be integrally rotatable. The idler pulley 112 is provided on the shaft 51 of the reduction gear 32 so as to be integrally rotatable. An endless belt 113 is wound around both the drive pulley 111 and the idle pulley 112. The rotation of the motor 33 is transmitted to the shaft 51 and further to the ball screw shaft 41 through the drive pulley 111, the belt 113, and the idler pulley 112.

In the second embodiment, the drive pulley 101, the idler pulley 102, and the two steering cables 103, 104 are used as a configuration for transmitting power from the steering wheel 14 to the input shaft 91 of the control valve 72, but a motor may be used instead of these components. In this case, an output shaft of the motor may be coupled to the input shaft 91 in an integrally rotatable manner, or may be coupled to the input shaft 91 through a speed reducer such as a worm speed reducer or a belt transmission mechanism, so that torque can be transmitted to the input shaft 91. The controller 15 controls the supply of electric power to the motor according to the steering angle θ detected by the rotation angle sensor 17. Since the motor is only used to rotate the input shaft 91, a smaller, lower power motor may be employed.

In the first and second embodiments, the controller 15 may control not only the steering actuators 13, 60 but also the engine 12a of the outboard motor 12. In the first and second embodiments, the rotation of the sector shaft 44 is transmitted to the steering bracket 23 through the lever 48 and the link 49, but the following configuration may be alternatively adopted as the power transmission mechanism between the sector shaft 44 and the steering bracket 23.

As shown in fig. 9, an interlocking shaft 44a is provided at a position (surface on the near side of the paper surface of fig. 9) near the teeth 45a in the upper surface of the sector gear 45. The interlocking shaft 44a is parallel to the fan-shaped shaft 44. The interlocking shaft 44a rocks leftward and rightward about the sector shaft 44 together with the sector gear 45. The upper end of the interlocking shaft 44a extends through the housing 40 or 80 and is exposed to the outside of the housing 40 or 80. The upper end portion of the interlock shaft 44a is slidably engaged in an elongated hole 23a provided in the steering bracket 23. Therefore, the steering bracket 23 and the sector gear 45 rock together leftward or rightward about the interlocking shaft 44 a. As a result, the outboard motor 12 turns left or right about the pivot shaft 22. Therefore, the lever 48 and the link 49 may be omitted from the configuration of the steering actuator 13. So that the configuration of the steering actuator 13 can be simplified.

In the first and second embodiments, the steering actuators 13, 60 are applied to the boat 10 equipped with the outboard motor 12, but may alternatively be applied to the boat 10 having an inboard motor, for example. As shown in fig. 11, an engine 12a as an inboard motor is provided inside the hull 10 a. The output of the engine 12a is transmitted to the propeller 12b through a propeller shaft 121 extending from the engine 12a to the stern. The end of the transmission shaft 121 on the side opposite to the engine 12a extends through the bottom of the hull 10a and is located outside the hull 10 a. The propeller 12b is integrally rotatably coupled to an end portion of the propeller shaft 121 on the opposite side from the engine 12 a. The rudder 122 is rotatably supported at the stern of the hull 10a by a support shaft 123. The steering actuator 13 or 60 is disposed near the stern of the hull 10 a. The lever 48 of the steering actuator 13 or 60 is coupled to the support shaft 123 via two links 124, 125. The link 124 extends in the left-right direction with respect to the advancing direction of the ship 10. The link 125 extends in the fore-and-aft direction of the hull 10 a. The link 124 is rotatably coupled at a first end thereof to the lever 48. The link 124 is rotatably coupled at a second end thereof to a first end of a link 125, the second end of the link 124 being an end on the opposite side from the lever 48. The link 125 is fixed at a second end thereof to the support shaft 123 of the rudder 122. Therefore, the rocking of the lever 48 to the left or right about the fan-shaped shaft 44 or 84 is converted into the rotation of the support shaft 123 by the two links 124, 125. When the rudder 122 rocks to the left or right about the support shaft 123, the advancing direction of the ship 10 changes.

Alternatively, the steering actuators 13, 60 may be applied to the boat 10 equipped with an inboard-outboard propulsion engine. In the inboard-outboard propulsion engine, the engine and the drive unit are integrated. In the drive unit, an outboard propeller and a mechanism that transmits the output of the engine to the propeller are integrated. The engine is arranged on the ship near the stern. The driving unit is provided at the stern to protrude to the outside of the ship. The drive unit is capable of rocking left and right relative to the hull 10a and also serves as a rudder for the ship 10. The rotation of the sector shaft 44 or 84 of the steering mechanism 31 or 71 of the steering actuator 13 or 60 is transmitted to the drive unit as a steering force acting to steer the drive unit, whereby the drive unit can be steered.

In the first embodiment, the marine steering device is implemented as the steer-by-wire type steering actuator 13 in which the power transmission between the steering wheel 14 and the outboard motor 12 is isolated, but the steering device may alternatively be implemented as a power steering device that assists the manual operation of the outboard motor 12. In this case, the ship 10 may adopt a configuration in which the steering wheel 14, the steering shaft 16, and the rotation angle sensor 17 are omitted. As shown by the two-dot chain line in fig. 2, a handle 12d extending toward the front side of the hull 10a is integrally provided on the housing 12c of the outboard motor 12. The operator manipulates the handle 12d leftward or rightward to steer the outboard motor 12. The outboard motor 12 or the handle 12d is provided with a torque sensor that detects the steering torque applied to the handle 12 d. The controller 15 controls the supply of electric power to the motor 33 in accordance with the steering torque detected by the torque sensor. Torque from the motor 33 is transmitted as assist force to the pivot shaft 22 via the speed reducer 32 and the steering mechanism 31, and steering of the outboard motor 12 is assisted by the handle 12 d. Alternatively, the steering actuator 60 of the second embodiment may be implemented as a power steering device. In this case, the controller 15 controls the supply of electric power to the electric pump 61 in accordance with the steering torque detected by the torque sensor.