JP2011073614A - Power steering device for small ship - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To arrange a torque sensor so that detection accuracy is not affected a lot by a shock load applied to a handle in order to enhance the detection accuracy of the torque sensor detecting steering torque in a power steering device for a small ship. <P>SOLUTION: An electric assist device 26 and a helm pump 27 are arranged in parallel on a common base 28. An input shaft 25 and an output shaft 33 of the electric assist device 26 are coaxially arranged, and are allowed to support a gear case 67 with bearings 68, 69 respectively. The input shaft 25 is connected to a handle shaft through a joint shaft 22. The torque sensor 30 which is a magnetic sensor is arranged around the input shaft 25 through a bearing 64 and bolted onto the gear case 67. The shock load applied to the input shaft 25 from the handle is escaped in an axial direction, and is not directly applied to the torque sensor 30. Therefore, the affection of the shock load in the torque sensor is reduced and the detection accuracy can be enhanced. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a steering device for a small boat, and more particularly to a power steering device with an electric assist.

In a small boat such as a boat equipped with power propulsion such as an outboard motor, a steering device provided with a power steering device is known.
As an example of this, a handle is rotatably supported on an instrument panel to which a cabin instrument or the like is mounted, and a power steering device and a hydraulic pump device are mounted in series on the handle shaft of the handle, and the hydraulic pump device is driven by assist output to generate hydraulic pressure. Some of them are generated and steered by rotating the outboard motor by this hydraulic pressure (see Patent Document 1).
This power steering device is an electric assist device having a worm gear driven by an electric motor and a worm wheel that meshes with the worm wheel and rotates the handle shaft, and detects a steering torque manually applied to the handle by a torque sensor. The electric motor is controlled so as to apply an appropriate assist force based on the detected value.
The hydraulic pump device is a helm pump, is configured as a swash plate type axial piston pump, and generates hydraulic pressure according to the output of the electric assist device.
Further, a handle having a tilt mechanism that can adjust the tilt angle with respect to the instrument panel is known (see Patent Document 2).

JP-A-2005-231383 JP 2000-43794 A

The torque sensor disclosed in Patent Document 1 includes a torque ring that moves in the axial direction on an input shaft connected to a handle shaft in accordance with steering torque, a torque pin that protrudes from the torque ring, and detection of a torque sensor on which the torque pin slides. Since the torque pin slides on the detection part of the torque sensor to detect the steering torque from the position of the torque pin, the torque pin and the detection part of the torque sensor are in direct contact with each other. The impact applied to the handle shaft is easily transmitted to the detection part of the torque sensor.
However, the torque sensor is a precise device, and when an impact load is applied to the detection unit, an error in the detection value increases, and accurate assist becomes difficult. Moreover, the torque sensor used in a small vessel such as a boat is in an environment where a large impact is easily applied due to waves or the like. Therefore, it is required to increase the detection accuracy of the torque sensor even in such an environment.
The present application aims to realize this demand.

In order to solve the above-mentioned problems, the invention of claim 1 relating to a power steering device for a small vessel,
Steering means disposed at the rear of the hull so as to be rotatable in a horizontal direction;
A pump device that generates hydraulic pressure by operating the steering wheel of the driver's seat in order to hydraulically drive the steering means;
In a power steering device for a small ship, comprising: a torque sensor that detects steering torque by a steering wheel operation; and an electric assist device that generates an assist force based on the torque detected by the torque sensor.
While connecting the input shaft of the electric assist device to the handle shaft,
The torque sensor is arranged around the input shaft so that an axial impact load applied from the handle to the input shaft is not directly applied to the detection part of the torque sensor.

According to a second aspect of the present invention, the torque sensor according to the first aspect is characterized in that the torque between the input shaft and the output shaft of the electric assist device is magnetically detected by the steering torque.

According to a third aspect of the present invention, in any one of the first or second aspects, the torque sensor is arranged around the input shaft via a bearing and fixed to the electric assist device.

According to a fourth aspect of the present invention, in any one of the first to third aspects, the electric assist device is supported by an instrument panel via a cylindrical holder, and the torque sensor is disposed inside the holder. To do.

According to a fifth aspect of the present invention, in the electric assist device according to any one of the third or fourth aspects, the input shaft and the output shaft are positioned on the same axis, and each of the electric assist devices is supported by a gear case of the electric assist device via a bearing. With
The bearing of the torque sensor is located above the bearing of the input shaft.

According to the invention of claim 1, while connecting the input shaft of the electric assist device to the handle shaft,
The torque sensor is arranged around the input shaft so that the axial impact load applied from the handle to the input shaft is not directly applied to the detection part of the torque sensor. Even if is applied, the impact load is removed in the axial direction of the input shaft and is not directly applied to the detection part of the torque sensor, so that the influence of the impact load of the torque sensor can be avoided and the detection accuracy of the torque sensor can be improved.

According to the invention of claim 2, since the torque sensor magnetically detects the torsion between the input shaft and the output shaft of the electric assist device by the steering torque, an impact load is generated between the detection portion of the torque sensor and the input shaft. Can be placed so that it is difficult to join.

According to the invention of claim 3, since the torque sensor is disposed around the input shaft via the bearing and is fixed to the electric assist device, the torque sensor indirectly contacts the input shaft, and the impact of the input shaft. The load is not directly applied to the detection part of the torque sensor. Further, by fixing the torque sensor to the electric assist device that supports the input shaft, the positional relationship between the detection portion of the torque sensor and the input shaft can be made constant.

According to the invention of claim 4, since the torque sensor is arranged inside the cylindrical holder that supports the electric assist device on the instrument panel, the torque sensor can be guarded by the holder.

According to the invention of claim 5, in the electric assist device, the input shaft and the output shaft are located on the same axis and are supported by the gear case of the electric assist device through the bearings, respectively, and the bearing of the torque sensor is connected to the input shaft. Since the bearing is positioned above the bearing, the detection unit of the torque sensor can be arranged at a portion with the least shake of the input shaft.

Schematic plan view of a motorized small boat to which the present invention is applied The figure which shows the attachment state of the steering hydraulic pressure generation unit with respect to an instrument panel Enlarged sectional view of the tilt mechanism External perspective view of steering hydraulic pressure generating unit Side view of steering hydraulic pressure generation unit Bottom view of steering hydraulic pressure generation unit Longitudinal sectional view along the center lines C, C1 and C2 of the steering hydraulic pressure generating unit 7 is an enlarged cross-sectional view of a part of FIG. Sectional view taken along line 9-9 in FIG. Helm pump longitudinal section Top view of common base

Hereinafter, an embodiment will be described based on the drawings.
FIG. 1 is a plan view of a power small boat to which the present invention is applied. In the following description, front and rear, left and right, and top and bottom are based on the straight traveling state of the hull, and the traveling direction is forward, and the left and right in the traveling direction are left and right.
A cabin 1 is provided in the center of the hull, and its bottom is a ship bottom 2. An instrument panel 3 is provided at the front of the cabin 1, and a handle 5 is supported via a tilt mechanism 4 so that the handle 5 can rotate and the tilt angle can be adjusted. The handle 5 is a ring-shaped steering wheel. Near the rear of the steering wheel 5 and the instrument panel 3, the right front position of the cabin 1 is a driver's seat. The position of the handle 5 is relatively low, and as a result, the driver's seat is also provided at a low position, realizing a low center of gravity.

A handle shaft (described later) of the handle 5 is connected to a steering hydraulic pressure generating unit 6 that is a power steering device, and generates hydraulic pressure corresponding to the amount of rotation of the handle 5. From the steering hydraulic pressure generating unit 6, the hydraulic pressure is applied to either the right turning pipe 7R or the left turning pipe 7L depending on the rotation direction of the handle 5 via the right turning pipe 7R and the left turning pipe 7L. Is given to.

The rear end of the right turning pipe 7R or the left turning pipe 7L is connected to a steering cylinder 8 provided at the rear end of the hull. The steering cylinder 8 is divided into a right chamber 11R and a left chamber 11L by a piston 10, and a right turning pipe 7R is connected to the right chamber 11R, and a left turning pipe 7L is connected to the left chamber 11L.

The piston 10 is integrated with a piston rod 12 that penetrates the steering cylinder 8 in the axial direction and is movable back and forth in the axial direction. One end of the link 13 is attached to one end of the piston rod 12 protruding from one end of the steering cylinder 8, and the other end of the link 13 is attached to the front end of the steering arm 14. The rear end of the steering arm 14 is integrated with the outboard motor 15.

The outboard motor 15 is a well-known steering means with a built-in engine. The outboard motor 15 can swing in the horizontal direction around the swivel shaft 16 in the vertical direction, and can swing up and down around the horizontal shaft 17. It is free. 18 is a propeller. However, the steering device of the present application may be a steering-dedicated member instead of such an outboard motor 15 with an engine.

When the handle 5 is turned to the right, the hydraulic pressure pressurized by the assist hydraulic drive from the steering hydraulic pressure generating unit 6 enters the right chamber 11R from the right turning pipe 7R and moves the piston 10 to the left. The hydraulic oil in the left chamber 11L reduced by the movement of the piston 10 is returned to the steering hydraulic pressure generating unit 6 from the left turning pipe 7L, and at the same time, the piston rod 12 extends to the left, and the link 13 extends to the tip of the steering arm 14. Since the side is pulled to the left side, the outboard motor 15 integrated with the steering arm 14 rotates counterclockwise about the swivel shaft 16 and steers the hull to the right.

Conversely, when turning to the left, reverse the above operation. Since the steering hydraulic pressure generating unit 6 includes an electric assist device, when the handle 5 is rotated, the hydraulic pressure by the steering hydraulic pressure generating unit 6 becomes larger than the input to the handle 5.

FIG. 2 is a sectional view showing a state in which the steering hydraulic pressure generating unit 6 is attached to the instrument panel 3.
The boss 20 of the handle 5 is attached to the upper surface of the instrument panel 3 via the tilt mechanism 4. The tilt mechanism 4 connects a handle shaft 21 extending downward from the center of the handle 5 and a joint shaft 22 connected to the steering hydraulic pressure generating unit 6 with a ball joint 23, so that the center line C of the handle 5 is relative to the instrument panel 3. It can be tilted around the horizontal axis L in the left-right direction in the front and back direction of the paper surface, and the tilt angle of the handle 5 with respect to the instrument panel 3 can be adjusted according to the driver's preference.

The joint shaft 22 vertically passes through the through hole 3 a of the instrument panel 3, the upper end is connected to the ball joint 23, and the lower end is connected to the input shaft 25 of the steering hydraulic pressure generating unit 6 via the joint 24.
The steering hydraulic pressure generating unit 6 includes an electric assist device 26 and a helm pump 27 arranged in parallel and integrated on a common base 28, and an input portion of the electric assist device 26 is an input shaft 25. The helm pump 27 is a known swash plate type axial piston pump.

The electric assist device 26 detects the manual steering torque of the handle 5 applied to the input shaft 25 by a torque sensor 30 attached to the upper portion of the electric assist device 26, and this is processed by the ECU 31. Thus, by driving the electric motor 32 that constitutes the electric assist device 26, a steering force (hereinafter simply referred to as a steering force) synthesized by adding the assist force to the manual steering torque is rotated and output to the output shaft 33. The output shaft 33 and the input shaft 25 are rotation axes of the electric assist device 26, respectively.

The ECU 31 transmits a steering force to the helm pump 27 via the transmission mechanism 34 and generates an appropriate hydraulic pressure from the helm pump 27. For example, a control map that associates the input torque with the assist force to be generated is provided, and by looking up the control map, an appropriate assist force according to the steering situation is determined, and the driver 39 (FIG. 9) is determined. The electric motor 32 is driven by commanding.
In the case of a single shaft type with only one propeller 18, since the hull 1 has a tendency to turn in the direction of rotation of the propeller 18, it is programmed in advance so that the assist force generated by the right rotation and the left rotation is different. You can also keep it.

The electric assist device 26 is supported in a suspended manner on the instrument panel 3 via an upper holder 35 and a lower holder 36 made of a rigid body such as metal. The upper holder 35 includes upper and lower flanges 35 a and 35 b, and the upper end flange 35 a is attached in contact with the lower surface of the instrument panel 3. The lower end flange 35 b is overlapped with a boss 36 a having a nut portion provided at the upper end of the lower holder 36, and fastened from above by a bolt 37. The height of the helm pump 27 is set such that the upper end portion is lower than the upper end portion position of the lower holder 36 attached to the electric assist device 26, and is disposed below the instrument panel 3, and here Thus, it can be connected to the right turning pipe 7R and the left turning pipe 7L.

The connecting portions of the upper holder 35 and the lower holder 36 each having a cylindrical shape are positioned so as to overlap the joint 24. Each end portion of the lower holder 36 is fastened to the upper surface of the electric assist device 26 with a bolt 38 from above by a boss 36b. Openings 36c are formed at a plurality of locations on the side surface of the lower holder 36, and the harness can be connected to the internal torque sensor 30 as well as reducing the weight of the lower holder 36. An opening 36c is also located at a position overlapping the joint 24 (see FIG. 5), and the bolt of the joint 24 can be attached and detached from here.

Next, the tilt mechanism 4 will be described in detail with reference to FIG. The tilt mechanism 4 includes a tilt frame 40 and a dustproof / waterproof rubber boot 41 covering the periphery. The tilt frame 40 includes left and right vertical wall portions 40a that are parallel to each other and a top portion 40b that connects between the upper ends of the sockets 42. The top portion 40b is provided with a long hole 40c that allows the handle shaft 21 to pass in the vertical direction. Yes. The long hole 40c is long in the front and back direction of the paper surface, and the handle shaft 21 is allowed to swing in the front and back direction of the paper surface in order to adjust the inclination angle.

A flange 40d is provided at the lower end of each tilt frame 40, abuts against the upper surface of the instrument panel 3, and is fixed with a bolt or the like (not shown). At this time, the flange 35a of the upper holder 35 can be brought into contact with the lower surface of the instrument panel 3 to be attached together with the vertical wall portion 40a. In this case, the upper holder 35, and consequently the steering hydraulic pressure generating unit 6, is supported by being suspended from the tilt mechanism 4 via the instrument panel 3.

The ball joint 23 includes a socket 42 and a ball 43. The socket 42 is fitted to the upper end portion of the joint shaft 22, and a spherical receiving portion that slidably supports the connecting portion 42a integrated with the bolt 44 and the ball 43. 42b.
The spherical portion of the ball 43 is slidably supported on the spherical receiving portion 42b, and each end portion of the handle shaft 21 is fitted in the central portion, together with the ball 43 and the socket 42, the center line C Are connected and integrated by a tilt shaft 45 along a horizontal axis L perpendicular to the center axis C. The ball 43 and the handle shaft 21 are rotatable around the tilt shaft 45 and can rotate integrally around the center line C.

For this reason, if the lock member (not shown) for adjusting the tilt angle provided between the handle shaft 21 and the tilt frame 40 is operated to be unlocked, the handle shaft 21 is rotated around the tilt shaft 45. The tilt angle of the handle shaft 21 can be freely adjusted by locking the lock member at a desired rotation angle and fixing the rotation position. The tilt mechanism 4 itself is not limited to this example, and various known mechanisms can be used.

Next, the steering hydraulic pressure generating unit 6 will be described in detail.
4 is an external perspective view of the steering hydraulic pressure generating unit 6, FIG. 5 is a side view, FIG. 6 is a bottom view, FIG. 7 is a longitudinal sectional view along the center line C, and FIG. It is.
4 and 7, in the steering hydraulic pressure generating unit 6, the assist device center axis C1 that is the axis of the input shaft 25 and the pump center axis C2 that is the axis of the pump shaft 46 that is the rotation shaft of the helm pump 27 are parallel. The manual input torque of the handle 5 applied to the joint shaft 22 is used as the steering force increased by the assist force of the electric assist device 26, and the corresponding hydraulic pressure is the Helm pump. 27 is discharged from a discharge port 47R or 47L provided in the upper part of the valve 27.

The discharge port 47R is connected to the right turning pipe 7R, and the discharge port 47L is connected to the left turning pipe 7L (see FIG. 1).
The pump shaft 46 is parallel to the output shaft 33. The output shaft 33 is coaxial with the input shaft 25 and the joint shaft 22, and the assist device center axis C <b> 1 of the input shaft 25 and the output shaft 33 coincides with the center line C of the handle 5.

A transmission cover 48 surrounds the transmission mechanism 34 in a skirt shape, and is made of an appropriate material such as metal or resin. The upper part is attached to the common base 28 and the lower part is opened (see FIGS. 5 and 6). Omitted). By providing the transmission cover 48, the transmission mechanism 34 can be prevented from being exposed, so that the electric assist device 26 and the helm pump 27 can be connected by the transmission mechanism 34.

6 and 7, the transmission mechanism 34 in this example is configured as a gear mechanism, and is configured by a drive gear 50 attached to the output shaft 33 and a driven gear 51 attached to the pump shaft 46, and meshes with each other. ing.
The gear ratio of this gear mechanism (the number of drive gears 50 / the number of driven gears 51) is greater than 1, and the rotational output of the output shaft 33 is increased and transmitted to the pump shaft 46. Note that the speed ratio can be arbitrarily set as long as the speed ratio can be increased more than 1.

By doing so, the pump efficiency of the helm pump 27 can be improved and the steering response can be improved. That is, as will be described later, the helm pump 27 has higher pump efficiency as the number of discharges of pressure oil by the axial piston increases, and the number of discharges of pressure oil by the axial piston is realized by speeding up the rotation of the pump shaft 46. . Therefore, if the steering force output from the electric assist device 26 is increased and transmitted to the pump shaft 46, the pump shaft 46 can be rotated faster to increase pump efficiency. As a result, the steering operation of the outboard motor 15 which is the steering means becomes rapid and steering with good response is possible, which is suitable for a ship steering apparatus that requires frequent and rapid steering.
In addition, since the transmission mechanism 34 is constituted by a gear train as a gear mechanism, the steering force can be accurately and promptly transmitted to the pump device.

Note that the gear mechanism of the transmission mechanism 34 can be made compact while adding an idle gear as needed to cope with changes in the inter-axis distance. Further, the gear ratio can be increased by using a multi-stage gear train. The transmission mechanism 34 is not limited to a gear mechanism, and various known transmission mechanisms are possible.

The electric assist device 26 and the helm pump 27 are arranged in parallel on the common base 28, and the transmission mechanism 34 is arranged below the bolt 28. In this way, the electric assist device 26, the helm pump 27, and the transmission mechanism 34 can be compactly integrated by the common base 28, and the rotation output of the output shaft 33 is transmitted to the pump shaft 46 by the transmission mechanism 34. Therefore, the degree of freedom in the layout of the helm pump 27 is increased, and the helm pump 27 that easily affects the output mechanism depending on the arrangement direction can be arranged in an appropriate posture in terms of performance.
In addition, since the pump shaft 46 and the output shaft 33 of the electric assist device are arranged in parallel, the structure of the transmission mechanism 34 that connects the shafts is simplified.
In addition, since the electric motor 32 and the pump device 27 are arranged on the left and right sides of the output shaft 33 of the electric assist device 26, when the upper part of the electric assist device 26 is supported on the instrument panel 3 above the output shaft 33, the left and right It becomes easy to balance the weight, and the power steering device can be stably suspended from the instrument panel.

In addition, since the steering hydraulic pressure generating unit 6 is a unit in which the electric assist device 26 and the helm pump 27 are arranged in parallel on the common base 28, the length of the steering hydraulic pressure generating unit 6 (in the direction of the assist device central axis C1) Is at most about the total length of the electric assist device 26 and the joint shaft 22 and is reduced to about ½ of the length when the electric assist device 26 and the helm pump 27 are connected in series. For this reason, the arrangement space below the instrument panel 3 is relatively small, and the distance between the bottom 2 and the instrument panel can be shortened. As a result, it is possible to arrange with a high degree of freedom in the space below the instrument panel 3 where there are many dimensional constraints, and it is possible to lower the driver's seat and lower the center of gravity. It becomes easy to stabilize.

Further, the steering hydraulic pressure generating units 6 are spread in the width direction although the axial direction is shortened due to the parallel arrangement. However, since the arrangement space below the instrument panel 3 has a relatively large margin in the left-right direction and the front-rear direction other than the height direction, it can be arranged in this space by parallel arrangement, increasing the degree of freedom of layout. Can do.
In addition, since the entire steering hydraulic pressure generating unit 6 is unitized, the entire unit can be supported by supporting the electric assist device 26 on the instrument panel 3 via the upper holder 35 and the lower holder 36.

Next, the electric assist device 26 will be described in more detail with reference to FIG. 7 and FIG. 8 which is an enlarged sectional view of a part thereof and FIG. 9 which is a sectional view taken along line 9-9 of FIG.
As shown in FIGS. 7 and 8, the input shaft 25 is a hollow shaft, and a torsion bar 60 is disposed in the shaft hole so that the longitudinal direction coincides with the axial direction. An upper end 60 a of the torsion bar 60 is integrated with an upper end of the input shaft 25 by a pin 61. The upper end of the input shaft 25 is coupled and integrated with the joint 24 by serration, and rotates integrally around the axis.

The lower end 60b of the torsion bar 60 is fitted in a dead end-shaped shaft hole 33b formed in the upper end 33a of the output shaft 33, and is integrated with the upper end 33a by serration coupling.
The upper end portion 33a is fitted on the outer periphery of the lower end portion of the input shaft 25 and is relatively rotatable. Therefore, a torque difference is generated between the manual steering force applied to the handle 5 and the load applied from the helm pump 27 side of the output shaft 33, the input shaft 25 and the output shaft 33 rotate relative to each other, and the torsion bar 60 is twisted. It is. Accordingly, the torque sensor 30 detects the amount of twist, whereby the necessary torque can be detected.

A worm wheel 65 is attached to the outer periphery of the output shaft 33 so as to be integrally rotatable. The worm wheel 65 meshes with a worm gear 66 (FIG. 9) driven by the electric motor 32.
A gear case 67 that accommodates the worm wheel 65 and the worm gear 66 is supported on the outer periphery of the output shaft 33 by bearings 68 and 69.

As shown in FIG. 8, the torque sensor 30 is a known magnetic sensor that is provided between the input shaft 25 and the output shaft 33 and is fixed to the upper portion of the electric assist device 26 by a bolt 63 with a boss 62. The torque sensor 30 includes coils 30a and 30b arranged in two upper and lower stages as a detection unit. The coils 30a and 30b are respectively wound in the circumferential direction on the bobbin 30d of the cylindrical portion 30c surrounding the input shaft 25 of the torque sensor 30, and are arranged to face each other close to the inside thereof. The voltage changes depending on the position of the core 52. It is like that.

The core 52 is made of an annular aluminum alloy and is integrated with the outer periphery of the torque ring 53. The torque ring 53 has a cylindrical shape and is slidable and detachable on the input shaft 25 in the axial direction. A spiral groove 54 and an axial longitudinal groove 55 are provided on the outer peripheral wall of the torque ring 53. A torque pin 56 that is press-fitted and integrated into the outer shaft 25 and protrudes radially outward is fitted, and a guide pin 57 that is press-fitted and integrated into the upper end portion 33a of the output shaft 33 and protrudes radially outward is fitted into the vertical groove 55. It is mated.
The torque ring 53 is urged upward by a coil spring 58, and the torque pin 56 is positioned at the center of the spiral groove 54 (when neutral).

When steering torque is applied from the handle to the input shaft 25, the torque ring 53 tries to rotate around the input shaft 25 by the torque pin 56 integral with the input shaft 25, but is rotated by the guide pin 57 integral with the output shaft 33. Movement is blocked. The guide pin 57 is fitted in the vertical groove 55 and allows relative movement of the guide pin 57 and the torque ring 53 in the axial direction.
Therefore, the torque ring 53 moves downward in the axial direction against the coil spring 58. Since the amount of movement is proportional to the amount of torsion of the torsion bar 60, the amount of movement of the core 52 is detected by voltage change in the coils 30a and 30b, and the steering torque can be detected by converting this to the amount of torque.

The torque sensor 30 is disposed on the outer periphery of the input shaft 25 via a bearing 64 and indirectly contacts the input shaft 25. However, the coils 30 a and 30 b that are detection units are not in contact with the core 52 and the torque ring 53. For this reason, an impact load applied in the axial direction of the input shaft 25 is released in the axial direction so as not to be directly applied to the detection portion of the torque sensor 30. The arrangement form of the torque sensor 30 that makes it difficult for the impact load in the axial direction to the input shaft 25 to be directly applied to the detection unit is referred to as non-contact.

In this way, by making the coils 30a and 30b, which are detection parts of the torque sensor 30, non-contact with the torque ring 53 of the input shaft 25, a large impact load peculiar to the ship applied to the input shaft 25 via the handle 5 is torque. Direct application to the detection unit of the sensor 30 can be avoided, and the detection error of the torque sensor 30 can be made as small as possible by impact load, so that a precise assist amount can be determined.
The torque sensor 30 does not necessarily have to be as in this example. In short, it is sufficient that the detection unit of the torque sensor 30 is not in contact with the input shaft 25 and the output shaft 33 side. A magnetic sensor, an optical sensor, or the like can be used as appropriate.

Only a part of the torque sensor 30 other than the detection unit is supported on the outer periphery of the input shaft 25 via a bearing 64.
In addition, the positional relationship between the torque sensor 30 and the input shaft 25 can be made constant by fixing the torque sensor 30 on the electric assist device 26 that supports the input shaft 25.
Moreover, the input shaft 25 and the output shaft 33 are coaxially supported and supported by the gear case 67 via bearings 64 and 68, respectively, and the bearing 64 of the torque sensor 30 is positioned above the bearing 68 of the input shaft 25. As a result, the torque sensor 30 can be disposed at a portion of the input shaft 25 with the least vibration.
Further, since the torque sensor 30 is disposed inside the cylindrical lower holder 36, the torque sensor 30 can be guarded by the lower holder 36.

As shown in FIG. 9, the worm gear 66 is formed on a worm shaft 70 coaxial with a motor axis C3 orthogonal to the assist center axis C1 of the electric assist device 26. The worm shaft 70 is coaxial with the output shaft 71 of the electric motor 32, and both ends of the gear case 67 sandwiching the worm gear 66 are supported by bearings 73 and 74.

In the electric motor 32, a motor case 75 is detachably attached to a mounting portion 67a formed in the gear case 67 by a bolt 76.
The gear case 67 is provided with bosses 36b and bosses 62 at approximately 120 ° intervals.

Next, the helm pump 27 will be described in detail with reference to FIG. FIG. 10 corresponds to a cross section that passes through the vicinity of the discharge port 47R and the discharge port 47L in FIG. 7 and is cut by a plane parallel to the pump center axis C2.
The pump shaft 46 disposed vertically in the center of the pump case 80 of the helm pump 27 protrudes downward through the bottom 80a, and the rotor 81 is integrated with the outer periphery of the pump case 80 so as to be integrally rotatable. Has been. An axial piston 82 is urged below the rotor 81 so as to protrude downward, and is in sliding contact with the surface of a shoe 84 that is a bearing provided on the swash plate 83. The shoe 84 is inclined along the swash plate 83.

A plurality of axial pistons 82 are arranged concentrically around the pump shaft 46 at equal intervals. When the tip (lower end) rotates integrally with the rotor 81 by the pump shaft 46 while sliding on the swash plate 83, the axial piston 82 is It continuously changes between the highest position A pushed upward by the swash plate 83 and the lowest position B from which the axial piston 82 protrudes downward, and the hydraulic oil is sucked in at the lowest position B, and the highest position. The hydraulic oil is compressed by A and the pressurized oil is pushed out to the oil passage 85R or the oil passage 85L. The oil passage 85R is connected to the discharge port 47R, and the oil passage 85L is connected to the discharge port 47L.

The oil passages 85R and 85L are provided with a check valve (not shown) for preventing the return, and when the rotor 81 rotates clockwise or counterclockwise by operating the handle, the check valve of the oil passage 85R or 85L in the rotation direction is added by the axial piston. It opens with the pressurized pressurized oil and is discharged from the discharge port 47R or 47L to be connected. At the same time, the check valve of the other oil passage 85L or 85R is opened with a part of this pressurized oil, and the return oil can be sucked. If pressurized oil is discharged from the discharge port 47R, the other discharge port 47L substantially becomes a suction port, sucks the return oil pushed out from the cylinder 8, and returns it to the pump from the oil passage 85L.

Although such a helm pump 27 is known as a manual input hydraulic pump device, it is not always necessary to adopt such a form, and various known forms can be adopted.

Next, details of the common base 28 will be described. FIG. 11 is a plan view of the common base 28. The common base 28 has a substantially oval shape made of metal, and a shaft hole 90 of the helm pump 27 and a shaft hole 91 of the output shaft 33 are formed in the major axis direction.

A concentric through-hole 92 is formed around the shaft hole 90, and the bottom portion 80 a of the pump case 80 is placed thereon and fastened through a bolt 93 (FIG. 7) from the lower surface of the common base 28. Is fixed on the common base 28.
At this time, if the through hole 92 is formed in an arc shape or a radial long hole, various helm pumps 27 having different attachment positions can be attached to the single common base 28.

Bosses 94 are formed around the shaft hole 91 at equal intervals on the same circumference. A gear case 67 is overlaid on the boss 94, and a bolt 96 is passed through the through hole 95 of the boss 94 from below. The electric assist device 26 can be attached to the common base 28 by fastening to a nut portion provided at the bottom of the common base 28.
At this time, if a large number of bosses 94 are provided in advance on the common base 28 with different circumferential intervals and radial distances, various electric assist devices 26 having different mounting positions can be integrated into a single common base 28. Can be installed.

As described above, the electric assist device 26 and the helm pump 27 are detachably attached to the common base 28 to be integrated into the steering hydraulic pressure generating unit 6, so that the electric assist device 26 is attached to the upper holder 35 as shown in FIG. And, by supporting the instrument panel 3 via the lower holder 36, the entire steering hydraulic pressure generating unit 6 can be easily supported on the instrument panel 3.
In addition, the common base 28 has a space for supporting the electric assist device 26 and the helm pump 27 in the upper portion and a space in which the transmission mechanism 34 is disposed in the lower portion, so that the upper and lower spaces can be partitioned according to function. The mechanism 34 can be accommodated efficiently.

The present application can be applied and modified in various ways. For example, the transmission mechanism can be driven by a chain or a belt. In this case, sprockets or pulleys are provided on the output shaft 33 and the pump shaft 46, respectively, and a chain or belt is wound around them. In this way, an inexpensive and reliable transmission mechanism can be obtained, and the length of the chain or belt can be changed relatively easily, so that the distance between the output shaft 33 and the pump shaft 46 can be easily changed. Thus, the degree of freedom in the layout of the electric assist device 26 and the helm pump 27 is increased.
It is also easy to set various speed ratios.
In addition, any number of idlers can be freely provided to adjust the length of the chain or belt.

In the case of a gear mechanism, the change in the inter-axis distance can be accommodated by interposing an idle gear.
Further, if a multi-stage gear train provided with an intermediate gear is used, the gear ratio (speed increasing ratio) can be increased and the entire apparatus can be made compact.
Further, if a planetary gear mechanism is adopted as the gear mechanism, the output shaft 33 of the electric assist device 26 is connected to the input side of the planetary gear mechanism, and the pump shaft 46 of the helm pump 27 is connected to the output side of the planetary gear mechanism. Thus, the steering force can be shifted and transmitted to the helm pump 27, and the electric assist device 26 and the helm pump 27 can be unitized in series.

Further, not only the planetary gear mechanism but also a normal gear train mechanism can be provided with a transmission mechanism that makes the transmission ratio variable. For example, there can be used a publicly known gear that is provided with a constantly meshing gear train and switches the connection with a dog clutch.
Furthermore, a speed change mechanism that can change the speed change ratio can also be adopted in chain drive and belt drive. In the case of chain drive, sprockets of different sizes are provided in multiple stages, and the chain is wound by selecting the sprocket.
In the case of belt driving, a known V pulley is provided, and the variable speed can be changed continuously by changing the width of the V groove.
By providing a speed change mechanism in this way, the speed change ratio (speed increase ratio) can be changed freely, the transmission ratio of the steering force can be changed over a wide range, and it can be adjusted to obtain the desired responsiveness. Can be achieved.

1: cabin, 2: ship bottom, 3: instrument panel, 4: tilt mechanism, 5: handle, 6: steering hydraulic pressure generating unit, 8: steering cylinder, 10: piston, 15: outboard motor, 21: handle shaft, 22: Joint shaft, 23: Ball joint, 24: Joint, 25: Input shaft, 26: Electric assist device, 27: Helm pump, 28: Common base, 30: Torque sensor, 32: Electric motor, 33: Output shaft, 34: Transmission mechanism, 35: Upper holder, 36: Lower holder, 46: Pump shaft, 48: Transmission cover, 60: Torsion bar, 67: Gear case

Claims (5)

Steering means disposed at the rear of the hull so as to be rotatable in a horizontal direction;
A pump device that generates hydraulic pressure by operating the steering wheel of the driver's seat in order to hydraulically drive the steering means;
In a power steering device for a small ship, comprising: a torque sensor that detects steering torque by a steering wheel operation; and an electric assist device that generates an assist force based on the torque detected by the torque sensor.
While connecting the input shaft of the electric assist device to the handle shaft,
The torque sensor is arranged around the input shaft so that an axial impact load applied from the handle to the input shaft is not directly applied to the detection part of the torque sensor. The power steering device for a small boat according to claim 1, wherein the torque sensor magnetically detects torsion between an input shaft and an output shaft of the electric assist device by the steering torque. The power steering device for a small boat according to claim 1 or 2, wherein the torque sensor is arranged around the input shaft via a bearing and is fixed to the electric assist device. The power for small ships according to any one of claims 1 to 3, wherein the electric assist device is supported by an instrument panel via a cylindrical holder, and the torque sensor is disposed inside the holder. Steering device. In the electric assist device, the input shaft and the output shaft are located on the same axis, and are supported by the gear case of the electric assist device via bearings, respectively.
The power steering device for a small boat according to claim 3 or 4, wherein the bearing of the torque sensor is located above the bearing of the input shaft.

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