JPH09142379A - Antirolling device for float structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable small force to suppress a rolling generated in a float struc ture. SOLUTION: A horizontal stage 14 is installed in a top part of a tower 13 vertically provided on a main hull 1. A solid mass is set up on the stage 14 capable of performing a reciprocating motion in the horizontal direction. A shake generated in the main hull 1 is transmitted to the solid mass through a tower 13, kinetic energy of the solid mass, generated in a high lift position, is transmitted to the main hull 1 through the tower 13, so as to suppress the shake of the main hull 1 by small force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-sway device used for suppressing the sway of a floating structure having a large turret structure such as an offshore drilling ship or a crane ship.

[0002]

2. Description of the Related Art Generally, an AR for a ship anti-sway device is used.
T (ANTI ROLLING TANK) and fin stabilizers are known. The ART uses a water tank to suppress the rolling of the ship. As shown in FIG. 4, the ART has an air communication pipe b between the upper end and the upper part of the main hull a.
Installed a U-tube type water tank c, which was communicated in the above, so that the water d in the water tank c passively resonated with the rolling of the main hull a, and the phase was delayed by 90 ° with respect to the rolling. The design is On the other hand, as shown in FIG. 5, the fin stabilizer is provided with a movable fin h which is moved by a drive device e in a bilge portion under the water surface at a substantially central portion in the bow-stern direction of the main hull a. The angle of sway, angular velocity, angular acceleration, etc. of the ship is detected by the sensor g, the angle of attack of the movable fin h is actively changed, and the horizontal force of the main hull a is suppressed by the lift generated on the movable fin h depending on the ship speed. It was done.

However, when the above-mentioned ART is used, the damping effect is reduced due to changes in the wave period and wave period of the ship, the stability of the small ship is affected, and the rear view is poor. There are problems such as becoming. Further, when the fin stabilizer is used, the anti-swing effect cannot be expected when the ship is stopped at low speeds, the work to outfit the main hull a is complicated, and the speed of the ship decreases because it is an additional hull. There are problems such as the cause.

Therefore, as a device which does not have the problems of the above-mentioned ART and fin stabilizer, a swinging device has been proposed in which a weight as a solid mass is reciprocally moved by driving a motor. FIG. 6 shows, as an example thereof, a type of anti-vibration device in which a weight is reciprocally moved by a pinion rack system, in which a weight 3 as a solid mass curved in an arc shape is mounted on a support roller 4. Is movably placed on the upper surface of the weight 3 along the moving direction, and is arranged above the rack 5 so as to be orthogonal to the rack 5. Axis 6
Is connected to a motor 7 as a driving device, a pinion 8 is attached to an intermediate portion of the shaft 6 so as to mesh with the rack 5, and the motor 5 is driven to rotate the pinion 8 via the shaft 6 to rotate the rack 5. At the same time, an anti-sway device main body 9 configured to reciprocate the weight 3 at a required cycle is installed on the main hull 1, and the shaking of the main hull 1 is detected at a required position of the main hull 1. Is attached to the drive unit 12 of the motor 7 based on the motion signal detected by the motion detection sensor 10, and a 90 ° delay phase and displacement signal with respect to the motion of the main hull 1 are generated. The control device 11 is provided.

According to the active type anti-vibration device as described above, when the main hull 1 undergoes a rolling motion due to waves or the like, when the vibration is detected by the motion detection sensor 10, it is based on the signal. The phase-controlled displacement signal is sent from the controller 11 to the drive unit 12, and the motor 7
The weight 3 is reciprocally moved to the left and right by being driven in the forward and reverse directions, and the kinetic energy is given to the main hull 1 in an optimum state, so that the shaking of the main hull 1 can be quickly suppressed. It is possible.

[0006]

However, the weight 3
In the case of the anti-sway device using the reciprocating motion of the ship, in order to effectively suppress the roll of the main hull 1, the weight 3 as a solid mass should be installed on the upper deck 2 at a position near the center of gravity of the main ship. Inevitably, the weight of the weight 3 required to obtain a sufficient damping effect is several% of the amount of drainage (corresponding to the dead weight of the ship). If it is adopted for a floating structure having a large self-weight such as a ship, the weight 3 becomes large, and the weight 3 becomes large, which requires a large occupied space on the upper deck 2. May interfere with other work performed in.

Therefore, the present invention aims to reduce the solid mass and further to adopt the floating structure for a floating structure having a large turret structure to provide an effective damping effect. Is to provide.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a horizontal solid mass at a required height position of the turret structure, which is separated from the center of gravity of the floating structure having the turret structure. It is configured so that it can be reciprocally moved in any direction.

Since the solid mass is installed at a high position in the tower structure, it is possible to suppress the swing of the floating structure with a small force. Therefore, the solid mass can be small.

Further, when the solid mass is reciprocated by the drive of the driving device, the solid mass can be downsized and the driving device can be downsized.

Furthermore, when the installation position of the solid mass on the stake structure is selected to be the highest position within the height range that does not impair the stability of the floating structure, the solid mass is further miniaturized and the drive unit is It is possible to reduce power consumption.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1A and 1B show an embodiment of the present invention, showing an example of application to an ocean excavation ship. That is, in a marine drilling vessel in which a tower tower 13 that is a large tower structure is erected on the upper deck 2 of the main hull 1, the stage 14 is installed on the top of the tower tower 13 as a high position. Then, on the stage 14, as shown in FIG. 6 as an example, the swinging device main body 9 which is capable of reciprocally moving the weight 3 as a solid mass by the motor 7 as a driving device, is attached to the weight 3 Installed so that the moving direction of the ship is the left-right direction (direction of arrow X), and the main hull 1
A shake detection sensor 10 for detecting the roll of the main hull 1 is attached at an appropriate position near the center of the vehicle, and a drive unit 12 that drives a motor 7 of the weight 3 is controlled based on a signal from the shake detection sensor 10. Control device 11 for sending a command
Are provided at appropriate places on the main hull 1 or the tower tower 13.

When the main hull 1 rolls, the sway is transmitted from the main hull 1 through the turret tower 13 to the stage 14 installed on the top of the turret tower 13. Therefore, based on the detection signal of the motion detection sensor 10, the motor 7 of the vibration reduction device main body 9 is driven in the forward and reverse directions, and the weight 3 is reciprocated left and right with a predetermined phase difference. Is transmitted to the main hull 1 via the turret tower 13, so that the horizontal hull of the main hull 1 can be quickly suppressed.

In the above description, the anti-sway device main body 9 is installed on the top of the turret tower 13 away from the center of gravity G of the main hull 1, and on the upper deck 2 near the center of gravity G of the main hull 1. When comparing, as shown in the moment diagram of FIG.
The distance from the center of gravity G to the top of the tower 13 is R, and the center of gravity G
Let r be the distance from the upper deck 2 to the upper deck 2, and let M and m be the masses of the weight 3 that restrains the rolling at that distance point, respectively.
Approximately, the relationship is RM = rm, and therefore M = m ×
It becomes (r / R), and it is understood that M becomes smaller as R becomes larger.

Therefore, in the present invention, the main hull 1
Compared with the case where the weight 3 is installed on the upper deck 2 close to the center of gravity G, the weight 3 used in the main body 9 of the vibration damping device can be made smaller and lighter, and the same vibration reduction effect can be obtained with a small amount of power. Further, since the anti-sway device body 9 is not placed on the upper deck 2 of the main hull 1, it is advantageous in that the space on the upper deck 2 can be effectively used.

The inventors of the present invention determined the difference in weight of the weight 3 when the swinging device main body 9 was installed on the top of the tower 13 and when it was installed on the upper deck 2. The setting condition at this time is that the maximum rolling angle (deg) of the main hull 1 when the anti-sway device main body 9 is not activated is 5 °, and the anti-sway device body 9 is activated to a maximum lateral roll angle of 3.75 °. Suppress the corners to achieve a target vibration reduction effect of 25%, and drainage of the main hull 1 to 20000
t, the lateral oscillation period of the main hull 1 is 22.42 s, the metacenter height (GM) is 1.2 m, the center of gravity height (KG) from the bottom of the main hull 1 is 10.7 m, and the anti-sway device body 9 Turret Tower 1 located 75.0m above center of gravity G of main hull 1
The calculation was performed on the upper deck 2 on the upper deck 2 and 10.0 meters above the center of gravity G of the main hull 1. As a result, when the anti-sway device body 9 is installed on the upper deck 2, the weight 3 has a weight of 250.
t is required, but when the anti-sway device main body 9 is installed on the top of the tower tower 13, the weight of the weight 3 may be 25 t,
The weight ratio can be 1/10.

In the above embodiment, the swinging device main body 9 is installed at the top of the tower tower 13 at a high position, but the point is that the weight of the damping device main body 9 is added. However, it is effective as long as it is within the height range that does not impair the stability of the main hull 1, and it is more advantageous to install it at the highest position within this height range.

Next, FIG. 3 shows a floating body structure having a large turret structure, which has a platform 16 above the floating body 15 and on which a tower tower 13 is erected. This shows an example of application to a submerged offshore structure, and by installing the vibration reduction device main body 9 on the top of the tower tower 13 in exactly the same manner as in the case of the offshore drilling ship shown in the above-mentioned embodiment, Rolling can be suppressed with a small driving force.

In the above embodiment, the active type anti-vibration device main body 9 may be other than the one shown in FIG. 6, and the anti-vibration device main body 9 may be used in order to cope with the rolling motion. 9 shows the case where the weight 3 is installed so that the moving direction of the weight 3 is in the left-right direction. Direction may be orthogonal to the front-rear direction, or an integrated type anti-vibration device body may be used in which the moving directions of the two weights 3 are preliminarily orthogonal to the horizontal direction. Good thing, on the other hand, weight 3
It is also possible to use a passive type that does not drive the weight. Even in this case, the weight 3 can be reduced in size and weight, and in addition to the offshore drilling vessel and the offshore structure shown in the embodiment, Needless to say, floating structures such as crane ships and observation ships can be similarly implemented, and various changes can be made without departing from the scope of the present invention.

[0021]

As described above, according to the rocking | fluctuation apparatus of the floating structure of this invention, a solid mass can be reciprocated horizontally in the high position of the tower structure away from the gravity center of the floating structure. Since it is installed on the floating structure, it is possible to suppress the sway of the floating structure at a high position of the tower structure with a small force, so that the solid mass can be made compact and lightweight, and moreover, on the upper surface of the floating structure. Since the space occupied by the solid mass can be eliminated, it does not hinder other work, and if a solid mass type driven by a drive device is adopted, the solid mass is of course downsized. That is, it is advantageous to be able to drive the solid mass with a small drive device, and the installation position of the solid mass is the highest position in the height range that does not impair the stability of the floating structure. By doing Miniaturization of mass, it is possible to maximize the burden on the small motorized and external power feeding apparatus of the drive apparatus, there is exhibited an excellent effect that.

[Brief description of the drawings]

FIG. 1 shows an embodiment of an anti-swing device for a floating structure according to the present invention, in which (a) is a schematic side view showing an example of application to a marine drilling vessel, and (b) is a front view.

FIG. 2 is a moment diagram for comparing the restraining force against rolling.

FIG. 3 is a schematic diagram showing an example of application to an offshore structure.

FIG. 4 is a schematic view showing an example of a conventional anti-vibration device.

FIG. 5 is a schematic view showing another example of the conventional anti-vibration device.

FIG. 6 is a schematic view showing an example of a recently proposed anti-sway device.

[Explanation of symbols]

 3 Weight (solid mass) 7 Motor (driving device) 13 Turret tower (turret structure)

Front Page Continuation (72) Inventor Seiya Yamashita, Shin Nakahara Town, Isogo Ward, Yokohama City, Kanagawa Prefecture Ishikawajima Harima Heavy Industries Ltd. Technical Research Institute

Claims (3)

[Claims] 1. A floating structure, wherein a solid mass is reciprocally movable in a horizontal direction at a required height position of the floating structure having a turret structure and away from the center of gravity of the floating structure. Anti-vibration device. 2. The rocking device for a floating structure according to claim 1, wherein the solid mass is reciprocated by the drive of the driving device. 3. The floating structure according to claim 1, wherein the installation position of the solid mass on the tower structure is selected to be the highest position within a height range that does not impair the stability of the floating structure. Anti-vibration device.