JP3121581B2 - Steering gear - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering device for rotating a rudder plate of a ship.

[0002]

2. Description of the Related Art FIG. 3 shows an example of a steering apparatus for a ship. This steering device includes a steering wheel 4 to which the rudder plate 2 is fixed, a turning arm 6 fixed to the steering wheel 4, a pair of hydraulic cylinder mechanisms 8, 10 for rotating the steering wheel 4, and a pair of And a ram 12 that constitutes an output section of the hydraulic cylinder mechanisms 8 and 10. The pair of hydraulic cylinder mechanisms 8 and 10 include cylinders 14 and 16, respectively. One end of the ram 12 is attached to one cylinder 14 so as to be extendable, and the other end of the ram 12 is extendable to the other cylinder 16. It is attached to. Rampin 1 on the ram 12
8 is fixed, and a receiving portion 20
Is provided, and the ram pin 18 is received in the receiving portion 20.

[0003] A hydraulic pump 22 is provided in association with the pair of hydraulic cylinder mechanisms 8 and 10, and the hydraulic pump 22 is driven by a motor 24. A switching control valve 26 is provided between the hydraulic cylinder mechanisms 8 and 10 and the hydraulic pump 22.
Is provided, the discharge port of the hydraulic pump 22 and the switching control valve 26 are connected via a supply line 28, and the return port of the hydraulic pump 22 and the switching control valve 26 are connected to a return line 30.
The switching control valve 26 and the cylinder side of one hydraulic cylinder mechanism 8 are connected via a first line 32, and the switching control valve 26 and the cylinder side of the other hydraulic cylinder mechanism 10 are connected to each other. It is connected via a second line 34.

In such a steering device, the switching control valve 26
Is in the neutral position shown in FIG. 3, the hydraulic oil from the hydraulic pump 22 is not supplied to the hydraulic cylinder mechanisms 8, 10, and the rudder plate 2 is held at that angular position. When the switching control valve 26 is switched from the neutral position to the first (or second) operating position to the right (or to the left) in FIG. 3, the pressure oil from the hydraulic pump 22 is discharged to one (or the other). It is fed to the hydraulic cylinder mechanism 8 (or 10), which causes the ram 12 to move to the right (or to the left) in FIG. It is rotated in the direction shown. Such a steering device is mainly applied to small and medium-sized ships.

FIG. 4 shows another example of a steering apparatus for a ship (see Japanese Utility Model Laid-Open No. 60-38899). In this steering apparatus, the configuration relating to the rudder plate 2, the rudder handle 4, the turning arm 6, the pair of hydraulic cylinder mechanisms 8, 10 and the ram 12 is substantially the same as the configuration shown in FIG. The hydraulic control system for expanding and contracting is different. That is, the double displacement type variable displacement pump 42 is used as a pump,
2 is driven by a motor 44. A switching control valve 46 is provided between the hydraulic cylinder mechanisms 8 and 10 and the variable displacement hydraulic pump 42, and one port of the variable displacement hydraulic motor 42 and the switching control valve 46 are connected via a first line 48. The other port of the variable displacement hydraulic pump 42 is connected to the switching control valve 46 via a second line 50, and the switching control valve 46 and the cylinder side of one hydraulic cylinder mechanism 8 are connected to the third The switching control valve 46 and the cylinder side of the other hydraulic cylinder mechanism 10 are connected via a fourth line 54.

In such a steering device, the switching control valve 46
Is in the non-operating position shown in FIG. 4, the pressure oil from the variable displacement hydraulic pump 42 is not supplied to the hydraulic cylinder mechanisms 8, 10, so that the rudder plate 2 is held at that angular position.
When the switching control valve 46 is switched from the non-operation position to the operation position to the left in FIG. 4 and the variable displacement hydraulic pump 42 is rotated in a predetermined direction (or in a direction opposite to the predetermined direction), the hydraulic pump The pressure oil from 42 is supplied to one (or the other) hydraulic cylinder mechanism 8 (or 10), whereby the ram 12 moves rightward (or leftward) in FIG. The rudder plate 2 is turned in the direction indicated by the arrow 56 (or 58). Such a steering device is mainly applied to a large ship.

[0007]

As will be understood from FIG. 3, the steering apparatus shown in FIG. 3 can be provided as a relatively simple and inexpensive steering apparatus.
Since the supply amount of the pressure oil supplied from the hydraulic pump 22 is constant, the pressure oil is rapidly supplied when the steering device is started,
Further, at the time of the stop, the supply of the pressure oil is suddenly stopped, and there is a problem that the shock at the time of starting and stopping is large. Further, since the supply of the pressure oil is suddenly stopped at the time of stop, there is a problem that it is difficult to accurately control the steering angle of the rudder plate 2.

The steering apparatus shown in FIG. 4 employs a double tilting type variable easy-to-use hydraulic pump 42. Therefore, the steering apparatus starts by controlling the discharge amount of pressure oil supplied from the variable displacement pump 22. The shock at the time of stop can be reduced, and the steering angle of the rudder plate 2 can be accurately controlled. However, as can be understood from FIG. There is a problem that the configuration of the control system is complicated and the manufacturing cost is high.

SUMMARY OF THE INVENTION An object of the present invention is to provide a steering apparatus capable of reducing a shock at the time of turning a rudder plate with a relatively simple structure.

[0010]

SUMMARY OF THE INVENTION The present invention provides a steering wheel 102 to which a rudder plate is fixed, cylinder mechanisms 110 and 112 for rotating the steering wheel, and a working fluid for supplying the cylinder mechanism. The tilting variable displacement pump 130, the tilt angle control means 132 for controlling the tilt angle of the swash plate of the tilting variable displacement pump, the tilting variable displacement pump and the cylinder Switching control valve 1 interposed between mechanism
60, and the tilt angle control means 132 controls the swash plate of the one tilt type variable displacement pump to a first tilt angle of a small tilt angle.
The switch control valve 160 is selectively positioned at a tilt position and a second tilt position having a large tilt angle. A second operating position for rotating the handle in a direction opposite to the predetermined direction, and a neutral position for stopping the rotation of the rudder handle, and the tilt angle control means 132 By switching the tilt position of the swash plate, the rotation speed of the steering wheel is switched, and by switching the position of the switching control valve, the rotation direction of the steering wheel is switched, whereby the tilt angle control means 132 is switched to a first tilting position when the steering wheel is rotated to the vicinity of an angle position to be set, and when the rotation of the steering wheel is stopped, the swash plate of the single tilt type variable displacement pump is moved to the first tilt position. 1 and the tilt angle control means 132 is turned off. After the control valve 160 is switched to the first or second operation position, the swash plate of the one-side tilt type variable displacement pump is moved to the second position when the rotation of the steering wheel is started for a predetermined time set by a timer. Holding it in the tilt position 1
After a predetermined time, the steering device is switched to the second tilt position. Further, according to the present invention, the tilt angle control means 132 includes an auxiliary pump 134, one end portion 142 which is set to a second tilt position by a working fluid, and one end portion 14
Pressure-receiving piston 140 having a pressure-receiving surface larger than 2 and having the other end 144 brought to the first tilt position by the working fluid.
When the working fluid from the auxiliary pump 134 is not operated,
An electromagnetic switching valve 154 that switches between a first operating position applied to the other end 144 of the pressure receiving piston 140 and a second operating position applied to the one end 142 when operated;
After the switching control valve 160 is switched to the first or second operating position, after the predetermined time has elapsed, the switching control valve 160 is switched from the second operating position to the first operating position until the steering wheel is set near the angular position to be set. A timer for switching from the second operating position to the first operating position when rotated.

According to the present invention, a single displacement type variable displacement pump is used, and the swash plate of the variable displacement pump is selectively positioned at the first displacement position and the second displacement position. The control system of the pump is simplified, and it can be provided as a relatively inexpensive device. In addition, by positioning the swash plate at the first tilt position when the rudder plate rotates, the tilt angle is reduced, whereby the amount of working fluid supplied from the variable displacement pump is reduced, and the working fluid is rapidly reduced. , And the shock at the time of rotation can be reduced.

[0012]

According to the present invention, the swash plate is held at the first tilting position when the rotation of the rudder plate is stopped. Therefore, after the feed amount from the variable displacement pump is reduced, the feed is stopped. Thus, the shock at the time of stopping the rotation can be reduced, and the steering angle control can be performed accurately. When the steering wheel is turned to the vicinity of the angular position to be set, it is switched to the first tilt position as described above.

[0014]

According to the present invention, the swash plate is held at the first tilting position when the rudder plate starts rotating, so that a shock at the time of starting the rotation can be reduced. After the switching control valve 160 is switched to the first or second operating position, the switching control valve 160 is held at the first tilt position for a predetermined time set by a timer,
Thereafter, the position is switched to the second tilt position.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a steering device according to the present invention will be described with reference to the accompanying drawings. FIG.
1 is a hydraulic circuit diagram showing one embodiment of a steering device according to the present invention.

Referring to FIG. 1, the illustrated steering apparatus includes a steering wheel 102 rotatably attached to the stern of a boat, and a steering plate 104 is fixed to the steering wheel 102. One end of a turning arm 106 is fixed to the steering wheel 102, and a receiving portion 108 formed of a substantially rectangular recess is provided at the other end of the turning arm 106.

The steering device includes a pair of cylinder mechanisms 110 and 112 for rotating the steering wheel 102, and a ram 114 that constitutes an output section of the pair of cylinder mechanisms 110 and 112. The cylinder mechanisms 110 and 112 have cylinders 116 and 118 arranged opposite to each other. One end of a ram 114 is attached to one of the cylinders 116 so as to be extendable and contractable. The end is mounted to be stretchable. A ram pin 120 is provided at the center of the ram 114 in the axial direction, and the ram pin 120 is received in the receiving portion 108 of the turning arm 106. Accordingly, when the ram 114 moves in the direction indicated by the arrow 122 (to the right in FIG. 1), the ram pin 120 also moves, thereby causing the swing arm 106,
The rudder handle 102 and the rudder plate 104 are integrally rotated in the direction indicated by the arrow 124. On the other hand, when the ram 114 moves in the direction indicated by the arrow 126 (to the left in FIG. 1), the ram pin 120 also moves, whereby the turning arm 106, the rudder handle 102 and the rudder plate 104 are integrally moved by the arrow 1
It is rotated in the direction indicated by 28.

In relation to the cylinder mechanisms 110 and 112,
Single tilt type variable displacement pump 1 which is a swash plate type piston pump
30 are provided. In addition, the tilting type variable displacement pump 130 is provided with tilting angle control means 132 for controlling the tilting angle of a swash plate (not shown). An auxiliary pump 134 is provided. The variable displacement pump 130 may be a single tilt type variable displacement hydraulic pump, and the auxiliary pump 134 may be an auxiliary hydraulic pump. The variable displacement pump 130 and the auxiliary pump 134
It is drivingly connected via a clutch means 136 to a drive source 138 which may be an electric motor. Therefore, the driving source 13
8 operates, the variable displacement pump 130 and the auxiliary pump 134 are rotated in a predetermined direction via the clutch means 136.

The tilt angle control means 132 has a pressure receiving piston 140 connected to a swash plate (not shown) of the single tilt type variable displacement pump 130. The outer diameter of one end 142 of the pressure receiving piston 140 is relatively small, and the one end 142 is movably received in the small pressure receiving chamber 146. On the other hand, the outer diameter of the other end 144 of the pressure receiving piston 140 is relatively large, and the other end 144 is movably received in the large pressure receiving chamber 148.

The discharge side of the auxiliary pump 134 is connected to the small pressure receiving chamber 146 via the first line 150. The second line 15 branches from the first line 150.
2 is provided, and the second line 152 is connected to the large pressure receiving chamber 148. Further, a switching valve 154 is provided in the second line 152. The switching valve 154 is constituted by an electromagnetic switching valve, and when the solenoid 155 is not operated, it is held at the first position shown in FIG.
When the shutter 5 is operated, it is held at the second position moved downward from the first position in FIG.

When the switching valve 154 is at the first position, the second line 152 is in a communicating state, and the pressure oil as the working fluid from the auxiliary pump 134 is supplied through the first line 150 to the small pressure receiving line. Is sent to the room 146,
The pressure is supplied to the large pressure receiving chamber 148 through the first and second lines 150 and 152. In this embodiment, since the pressure receiving area (the area of one end face) of the one end 142 of the pressure receiving piston 140 is smaller than the pressure receiving area (the area of the other end face) of the other end 144, the pressure acting on both end faces of the pressure receiving piston 140. Due to the difference in the operating force due to the oil, the pressure receiving piston 140 moves to the left in FIG. 1, whereby the swash plate (not shown) is held in the first tilt position where the tilt angle is small, The discharge amount of the working fluid from the variable displacement pump 130 is reduced. The discharge amount from the variable displacement pump 130 when the swash plate is located at the first tilt position is, for example, 30 times the discharge amount when the swash plate is positioned at the second tilt angle. ~
It is set to about 40%.

On the other hand, when the switching valve 154 is switched and positioned at the second position, the second line 1
52 and the return line 156 are communicated with each other, and the large pressure receiving chamber 148 is provided.
The internal pressure oil is returned to a fluid reservoir 158, such as an oil tank, through a return line 156. Therefore, the auxiliary pump 13
4 acts on the small pressure receiving chamber 146, and the pressure oil in the small pressure receiving chamber 146 causes the pressure receiving piston 140 to move rightward in FIG. 1, whereby the swash plate (not shown)
The tilt angle is held at the second tilt position where the tilt angle is large, and the discharge amount of the working fluid from the variable displacement pump 130 increases.

A switching control valve 160 is provided between the single tilt type variable displacement pump 130 and the pair of cylinder mechanisms 110 and 112, and the switching control valve 160 and the discharge port of the variable displacement pump 130 are connected via a supply line 162. The switching control valve 160 and the return port of the variable displacement pump 130 are connected via a return line 164. Further, the switching control valve 160 and the cylinder side of one cylinder mechanism 110 are connected via a third line 166, and the switching control valve 160 and the cylinder side of the other cylinder mechanism 112 are connected to a fourth line 168. Connected through. The switching control valve 160 is constituted by an electromagnetic switching control valve, and is held at the neutral position shown in FIG. 1 when both the solenoids 161 and 163 are inactive, and when one of the solenoids 161 is operated, the neutral position is shifted from the neutral position to the right. 2 is switched to the first operating position shown in FIG.
When the switch 63 is operated, it is held at the second operation position switched from the neutral position to the left. When the switching control valve 160 is at the neutral position, the supply line 162 and the return line 164 communicate with each other, and the hydraulic oil discharged from the variable displacement pump 130 as the working fluid is supplied to the supply line 162
And this variable displacement pump 1 through the return line 164
Return to 30. Therefore, the pressure oil is not supplied to the pair of cylinder mechanisms 110 and 112, and
Is held at that angular position, for example, the angular position shown in FIG. When the switching control valve 160 is positioned at the first operation position shown in FIG. 2, the supply line 162 and the third line 166 are connected, and the return line 164 and the fourth line 168 are connected. . Thus, the pressure oil discharged from the variable displacement pump 130 is supplied to the supply line 1
62 and the third line 166 through the cylinder mechanism 1
10 and the pressure oil on the cylinder side of the other cylinder mechanism 112 is supplied to the fourth line 168.
And return to the pump 130 through the return line 164. Accordingly, the ram 114 moves in the direction indicated by the arrow 122, and the steering wheel 102 (the steering plate 104 integrally therewith) is rotated in a predetermined direction indicated by the arrow 124. When the switching control valve 160 is positioned at the second operation position, the supply line 162 and the fourth line 168 communicate with each other, and the return line 164 and the third line 166 communicate with each other. Thus, the pressure oil discharged from the variable displacement pump 130 is supplied to the supply line 162 and the fourth line 1.
While being supplied to the cylinder side of the other cylinder mechanism 112 through 68, the pressure oil on the cylinder side of the cylinder mechanism 110 returns to the pump 130 through the third line 166 and the return line 164. Therefore, the ram 11
4 moves in the direction indicated by arrow 126, and the steering wheel 102 (the steering plate 104 integrally therewith) is turned in the direction opposite to the predetermined direction indicated by arrow 128.

In this steering system, the variable displacement pump 130
Is connected to the fluid reservoir 158 via a supply line 170, and the hydraulic oil in the fluid reservoir 158 is supplied to the variable displacement pump 130 via the supply line 170. The supply line 170 is provided with a check valve 172 for preventing the backflow of the hydraulic oil. Also, the auxiliary pump 134
Is connected to the fluid reservoir 158 via a fifth line 174, and the hydraulic oil in the fluid reservoir 158 is supplied to the auxiliary pump 134 through the fifth line 174. First line 15
0 is the relief line 17 connected to the fluid reservoir 158
8 is connected, and a relief valve 176 is provided in the relief line 178. Therefore, the first line 1
When the pressure of the pressure oil supplied through the line 50 increases, the relief valve 176 is opened, and a part of the pressure oil flowing through the first line 150 is returned to the fluid reservoir 158 through the relief line 178, and the first line is discharged. The pressure of the pressure oil fed through 150 is maintained at a predetermined value. Although not shown, if necessary, between the third line 166 and the fourth line 168, in order to prevent the pressure of the pressure oil in these lines 166, 168 from abnormally increasing. Can be provided.

The operation of the above-described steering device will be described as follows. Referring mainly to FIG.
Is turned in the direction indicated by the arrow 124 (or 128), the solenoid 161 (or 163) is operated,
The switching control valve 160 is located at the first operating position (or the second operating position) shown in FIG. At this time, the solenoid 155 is held in a non-operating state, and the switching valve 154 is
The swash plate of the variable displacement pump 130 is held at the first position shown in FIGS. 1 and 2 and the displacement angle of the pressure oil is discharged from the variable displacement pump 130. Is kept low. Therefore, when the switching control valve 160 is located at the first operating position (or the second operating position), the pressure oil from the variable displacement pump 130 is supplied to the supply line 162 and the third line 166 (or the fourth line).
Is fed to the cylinder mechanism 110 (or 112) through the line 168), and the rudder plate 104 is rotated in the direction indicated by the arrow 124 (or 128) via the ram 114 and the steering wheel 102. , The movement of the ram 114 in the direction indicated by the arrow 122 (or 126) and the turning of the rudder plate 104 in the direction indicated by the arrow 124 (or 128) are performed relatively slowly. Shock is relieved.

After a lapse of a predetermined time, for example, 1 to 2 seconds, after the switching control valve 160 is switched to the first operating position (or the second operating position), the solenoid 155 is operated, and the switching valve 154 is switched to the second operating position. Switched to position. Thus, the pressure oil in the large pressure receiving chamber 148 is returned to the fluid reservoir 158 through the return line 156, and the pressure receiving piston 140 is moved rightward in FIG.
The swash plate (not shown) of the variable displacement pump 130 is held at the second tilt position where the tilt angle is large. Therefore, the discharge amount of the working fluid from the variable displacement pump 130 increases,
Accordingly, the moving speed of the ram 114 and the turning speed of the rudder plate 104 in the direction indicated by the arrow 124 (or 128) are increased, and the steering speed of the rudder plate 104 can be increased. The predetermined time during which the switching valve 154 is switched is set to a desired time by, for example, a timer (not shown).

When the rudder plate 104 rotates to the vicinity of the angular position to be set, the solenoid 155 is deenergized, and the switching valve 154 is switched to the first position again. Thus, the pressure oil from the auxiliary pump 134 is
0, the pressure receiving piston 140 moves to the left in FIGS. 1 and 2, and the swash plate (not shown) of the variable displacement pump 130 has the first tilt having a small tilt angle. It is held in the shift position. Therefore, the variable displacement pump 13
The discharge amount of the pressure oil from 0 is reduced, thereby reducing the ram 1
The movement speed of the steering wheel 14 and the rotation speed of the rudder plate 104 in the direction indicated by the arrow 124 (or 128) decrease.

Thereafter, when the rudder plate 104 rotates to an angle to be set, the solenoid 161 (or 163) is deenergized, the switching control valve 160 is positioned at the neutral position, and thus the rotation of the rudder plate 104 stops. I do. As described above, when the rotation of the rudder plate 104 is stopped, the supply is stopped after the discharge amount from the variable displacement pump 130 is reduced, so that the shock at the time of stopping the rotation can be reduced. Further, when the rotation is stopped, the moving speed of the ram 114 and the rotating speed of the steering plate 104 are reduced, so that the steering plate 104 can be accurately positioned at an angle to be set.

When the rotation is stopped, the solenoid 155 of the switching valve 154 is deenergized, and the solenoid 16 of the switching control valve 160 is turned off.
The deenergization of 1 (or 163) can be performed, for example, by performing the following control. For example, an angle detection sensor (not shown) for detecting the angle position of the rudder plate 104 in relation to the steering wheel 102 is provided, and the detection angle detected by the angle detection sensor is 3 to 3 before the angle to be set.
The solenoid 155 of the switching control valve 160 is deenergized when rotated to around 5 degrees, and when the detection angle detected by the angle detection sensor substantially matches the angle to be set. (Or 16
3) can be controlled to deactivate.

When the steering angle is small, for example, within 5 degrees, it is desirable to keep the switching valve 154 at the first position without switching. With this configuration, the variable displacement pump 13 can be operated in a relatively short time.
The discharge amount of the pressure oil from 0 is not switched, the shock is reduced, and the rudder plate 104 can be accurately positioned.

The embodiment of the steering apparatus according to the present invention has been described above. However, the present invention is not limited to such an embodiment, and various modifications and corrections can be made without departing from the scope of the present invention. is there.

For example, in the illustrated embodiment, the switching valve 154 is held at the first position when the rotation is started, and the switching valve 154 is positioned at the second position after a lapse of a predetermined time from the start. Is not a particular problem, the switching valve 134 can be positioned at the second position from the beginning of the rotation.

For example, the single-tilt type variable displacement pump may be an oblique-axis type piston pump. In this case, the swash plate is realized by a member for guiding the piston fixed to the oblique axis. As described above, the single tilt type variable displacement pump may be another pump.

[0035]

According to the steering apparatus of the present invention, a single-tilt type variable displacement pump is used, and the swash plate of the variable displacement pump is connected to the first swash plate.
Since the tilting position and the second tilting position are selectively positioned, the control system of the variable displacement pump is simplified, and a relatively inexpensive device can be provided. In addition, by positioning the swash plate at the first tilt position when the rudder plate rotates, the tilt angle is reduced, whereby the amount of working fluid supplied from the variable displacement pump is reduced, and the working fluid is rapidly reduced. , And the shock at the time of rotation can be reduced. Further, since the rotation speed of the steering wheel is determined by the discharge amount of the working fluid from the one-side tilt type variable displacement pump, and the rotation direction of the steering wheel is determined by switching the switching control valve, The rotation of the rudder handle can be controlled with a relatively simple configuration.

Further, according to the steering apparatus of the present invention, the swash plate is held at the first tilt position when the rotation of the rudder plate is stopped. Is stopped, so that the shock at the time of rotation stop can be reduced, and the steering angle control can be accurately performed.
Further, according to the present invention, as described above, when the steering wheel is rotated to the vicinity of the angular position to be set, it is switched to the first tilt position as described above, and the discharge amount of the pump is increased.

Further, according to the steering device of the present invention, the swash plate is held at the first tilting position when the turning of the rudder plate is started, so that the shock at the time of starting the turning can be reduced. After the switching control valve 160 is switched to the first or second operating position, the switching control valve 160 is held at the first tilt position for a predetermined time set by the timer, and after the predetermined time, returns to the second tilt position. Switch to reduce the pump output.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram schematically showing an embodiment of a steering device according to the present invention.

FIG. 2 is a hydraulic circuit diagram schematically showing a state in which a steering plate is rotated in a predetermined direction in the steering device of FIG.

FIG. 3 is a hydraulic circuit diagram schematically showing an example of a conventional steering device.

FIG. 4 is a hydraulic circuit diagram schematically showing another example of a conventional steering device.

[Explanation of symbols]

 102 rudder handle 104 rudder plate 110, 112 cylinder mechanism 114 ram 120 ram pin 130 one-side tilt type variable displacement pump 132 tilt angle control means 134 auxiliary pump 140 pressure receiving piston 154 switching valve 160 switching control valve 162 supply line 164 return line 166 Line 3 168 Line 4

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B63H 25/30

Claims (2)

(57) [Claims] 1. A steering wheel 102 to which a rudder plate is fixed, cylinder mechanisms 110 and 112 for rotating the steering wheel, and a tilting variable displacement pump for supplying a working fluid to the cylinder mechanism. 130 and tilt angle control means 132 for controlling the tilt angle of the swash plate of the single tilt type variable displacement pump.
And a switching control valve 160 interposed between the one-side tilt type variable displacement pump and the cylinder mechanism. The tilt angle control means 132 comprises: Are selectively positioned at a first tilt position where the tilt angle is small and a second tilt position where the tilt angle is large, and the switching control valve 160 turns the steering wheel in a predetermined direction. A first operating position, a second operating position for rotating the steering wheel in a direction opposite to the predetermined direction, and a neutral position for stopping the rotation of the steering wheel, By switching the tilt position of the swash plate by the tilt angle control means 132, the rotation speed of the steering wheel is switched, and by switching the position of the switching control valve, the rotation direction of the steering wheel is changed. The tilt angle control means 132 sets the steering wheel. When rotated to the vicinity of the angular position to be switched, it is switched to the first tilt position,
When the rotation of the helm is stopped, the swash plate of the single-tilt type variable displacement pump is held at the first tilting position. After switching to the second operating position, the swash plate of the one-tilt variable displacement pump is held at the first tilting position when the rotation of the steering wheel is started for a predetermined time set by a timer. After a predetermined time, the steering device is switched to the second tilt position. 2. The tilt angle control means 132 includes an auxiliary pump 134 and one end portion 142 which is set to a second tilt position by a working fluid.
A pressure receiving piston 140 having a pressure receiving surface larger than its one end 142 and having the other end 144 brought to a first tilted position by the working fluid; A first operating position applied to the other end 144 of the piston 140 and a second operating position applied to the one end 142 when actuated;
After the predetermined time has elapsed after the electromagnetic switching valve 154 and the switching control valve 160 are switched to the first or second operating position, the first operating position is switched from the second operating position to the first operating position. 2. The steering system according to claim 1, further comprising a timer for switching from the second operating position to the first operating position when the operating position is switched to a position near the angular position to be set.