JP2007069685A - Cable engine and cable laying ship using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cable engine capable of simply and accurately measuring the tension of a cable, and facilitating maintenance. <P>SOLUTION: The cable engine comprises a drum 11 paying out the cable 9 to a sheave 7 provided at a bow, motors 13, 15 driving the drum 11 to rotate, and torque detectors 27, 29 equipped to driving shafts 19, 21 of the motors 13, 15. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a cable engine as a cable feeding device and a cable laying ship using the same.

When laying submarine cables or the like using a cable laying ship, the cable is pulled out from the hold using a cable engine and sent to the bow or stern sheave so that the cable is fed into the sea according to the ship speed.
In such work, if the cable feeding speed and the ship speed do not match, the cable may be tensioned more than necessary, and the cable may be damaged.
Therefore, a cable laying ship is provided with a cable engine and a mechanism for measuring the tension applied to the cable, and the cable feeding speed is controlled to prevent the cable from being damaged.

As a mechanism for measuring the tension of the cable, for example, a dynamometer system as shown in Patent Document 1 is often used. Further, an internal dynamometer method that can improve detection accuracy as shown in Patent Document 2 has been proposed.
In the dynamometer method, the dynamometer is installed on the cable movement line so that the cable is supported at a predetermined angle, and the cable is placed downward by a load cell provided between the dynamometer hull-side fixing part and the cable support part. The component force is measured, the downward component force of the cable is converted, and the cable tension is calculated.
In the internal dynamometer method, a load cell is installed between a drum that draws out a cable and the hull, the force by which the drum is pulled by the load cell is measured, and this is converted into the tension of the cable.

JP-A-53-80693 JP 2001-258116 A

However, in the dynamometer method, an error based on the accuracy of a predetermined angle given to the cable to generate a component force, an error expansion to calculate backward from a downward component force that is minimal compared to the tension, and the tare load of the load cell There was a problem that the accuracy of tension detection was insufficient due to errors and the like based on fluctuations caused by movement.
Further, the internal dynamometer method directly detects the tension by the load cell, and thus the detection accuracy is improved as compared with the dynamometer method, but the influence of the change in the tare load of the load cell due to the hull motion still exists. In order to eliminate this, it is necessary to correct by installing an inclination angle sensor, an accelerometer, or a correction load cell, so that the device is complicated and expensive, and it is difficult to reliably correct complicated hull movement. . Furthermore, since the load cell is installed under the drum, it is necessary to lift the drum in order to replace the load cell, which makes it difficult to work during navigation and has poor maintenance.

  In view of the above problems, an object of the present invention is to provide a cable engine that can easily and accurately measure the tension of a cable and that can be easily maintained, and a cable laying ship using the cable engine.

In order to solve the above problems, the present invention employs the following means.
That is, a cable engine according to the present invention includes a drum that feeds a cable to a sheave provided at a ship end, a rotation driving unit that rotationally drives the drum, and a torque detector that is mounted on a drive shaft of the rotation driving unit. And is provided.

Thus, since the torque applied to the drive shaft of the rotation drive means for rotating the drum is detected by the torque detector, the torque corresponding to the tension of the cable fed from the drum can be directly detected. In addition, since the detection value of the torque detector is not affected by the hull motion, the cable tension can be measured easily and accurately.
Further, since the torque detector can be removed by removing the shaft coupling, maintenance can be easily performed.

  In the cable engine according to the invention, a speed reduction means is interposed between the drum and the rotation drive means, and the torque detector is attached to a drive shaft on the rotation drive means side. Do

  Thus, since the speed reduction means is interposed between the drum and the rotation drive means, and the torque detector is mounted on the drive shaft on the rotation drive means side, the torque detector is smaller than the torque applied to the drum. Torque will be detected. For this reason, since a small torque detector can be used, an apparatus can be made cheap.

  The cable engine according to the invention further includes a control device that calculates the tension of the cable from the torque value detected by the torque detector, and controls the rotational speed of the rotation driving means according to the magnitude of the tension. It is characterized by.

As described above, the cable tension is calculated from the torque value detected by the torque detector, and the controller for controlling the number of rotations of the rotation driving means according to the magnitude of the tension is provided. When it is determined that the tension is excessive, the rotational speed of the rotation driving means can be increased, and when it is determined that the tension is excessive, the rotational speed of the rotation driving means can be decreased.
Thereby, since the magnitude | size of the tension | tensile_strength concerning a cable can be maintained in a predetermined range by controlling the delivery speed | rate of a cable, damage to a cable can be prevented.

  A cable laying ship according to the present invention is equipped with the cable engine according to any one of claims 1 to 3.

As described above, since the cable engine capable of accurately measuring the tension applied to the cable is mounted, the tension applied to the cable can be kept within a predetermined range regardless of a change in the situation such as the ship speed.
As a result, damage to the cable can be prevented, so that reliable cable laying can be performed.

According to the present invention, the torque applied to the drive shaft of the rotation drive means for rotating the drum is detected by the torque detector, so that the cable tension can be measured easily and accurately.
Further, since the torque detector can be removed by removing the shaft coupling, maintenance can be easily performed.
As a result, damage to the cable can be prevented, so that reliable cable laying can be performed.

Hereinafter, a cable laying ship 1 according to an embodiment of the present invention will be described with reference to FIGS. Note that the present invention is not limited to the embodiments.
FIG. 1 is a partial side view showing a bow portion with a part cut away.
The cable laying ship 1 includes a hull 3, a cable engine 5, and a sheave 7.
A large number of cables 9 are stored in a hold (not shown) of the cable laying ship 1.
The cable 9 is wound up by the drum 11 of the cable engine 5 and sent out to the sheave 7 when necessary for the necessary amount from the hold.

The drum 11 that winds up the cable 9 needs a large radius of curvature in relation to the bending rigidity of the cable 9, and is fixed to the hull 3 at a position lower than the deck.
The sheave 7 is a pulley attached to the bow, and is configured to guide the cable 9 fed from the drum 11 and feed it into the sea.
The uppermost part of the drum 11 and the uppermost part of the sheave 7 are installed so as to have the same height.
In this embodiment, the sheave 7 is provided at the bow, but may be provided at the stern.

FIG. 2 is a plan view showing a schematic configuration of the cable engine 5, and FIG. 3 is a side view.
The cable engine 5 includes a drum 11 that winds and sends the cable 9, a pair of electric motors (rotation drive means) 13 and 15 that rotationally drive the drum 11, and a control device 17.
Drive gears 23 and 25 are fixed to the drive shafts 19 and 21 of the electric motors 13 and 15 at the tip portions, and torque detectors 27 and 29 are interposed in the middle portions.

The drive gears 23 and 25 are meshed with a drum gear 31 attached to the shaft end of the drum 11.
Since the pitch circle of the drum gear 31 is configured to be larger than the pitch circle of the drive gears 23 and 25, the drum gear 31 and the drive gears 23 and 25 constitute the speed reducing means of the present invention.
In addition to this, a speed reducer may be interposed as the speed reducing means.
The control device 17 calculates the tension using the detection signals from the torque detectors 27 and 29, and controls the rotation speed of the electric motors 13 and 15 (drum 11) based on the calculation result.

The torque detectors 27 and 29 will be described with reference to FIG. Since the torque detectors 27 and 29 have the same structure, the torque detector 27 will be described here.
FIG. 4 is a front view showing the mounting structure of the torque detector 27.
The torque detector 27 includes a torsion bar 33, a first gear 35, a second gear 37, a first electromagnetic detector 39, and a second electromagnetic detector 41.

The first gear 35 and the second gear 37 are fixed to both ends of the torsion bar 33.
The first gear 35 is fixed to the drive shaft 19 on the drum 11 side, and the second gear 37 is fixed to the drive shaft 19 on the electric motor 13 side.
The first electromagnetic detector 39 is installed in the vicinity of the peripheral surface of the first gear 35 and detects a periodic change in magnetic resistance accompanying the rotation of the first gear 35.
The second electromagnetic detector 41 is installed in the vicinity of the peripheral surface of the second gear 37 and detects a periodic change in magnetic resistance accompanying the rotation of the second gear 37.

The laying work of the cable 9 by the cable laying ship 1 described above will be described.
The cable laying ship 1 navigates along the cable laying line.
During the navigation, the motors 13 and 15 are operated to rotate the drum 11 via the drive shaft 19, the drive gears 23 and 25, and the drum gear 31.
In this way, the cable engine 5 is driven, the cable 9 is pulled out from the hold, and is wound around the drum 11. In the drum 11, the cable 9 is wound substantially once and sent out toward the sheave 7. The cable 9 is fed from the sheave 7 into the sea, sunk into the seabed, and laid.

At this time, if the feeding speed of the cable 9 does not match the ship speed, the cable 9 may be tensioned more than necessary, and the cable 9 may be damaged.
Therefore, the operation of the cable engine 5 is controlled so that the tension applied to the cable 9 falls within a predetermined range.
This control method will be described.

First, a method for detecting the tension T applied to the cable 9 will be described.
Torque detectors 27 and 29 detect torque acting on the drive shafts 19 and 21 of the electric motors 13 and 15.
That is, for example, when the drive shaft 19 rotates, the torsion bar 33 is twisted by the applied torque, and the rotational phase of the first gear 35 is delayed from the rotational phase of the second gear 37. Since the rotational phase delay is proportional to the torque, the rotational phases of the first gear 35 and the second gear 37 are compared to calculate the torque.
In this manner, torques Tr1 and Tr2 acting on the drive shafts 19 and 21 are detected by the torque detectors 27 and 29.

となる。 The pitch circle radius of the drive gears 23 and 25 is Dd, the pitch circle radius of the drum gear 31 is Dg, and the radius of the drum 11 is Dr.
Since the drum 11 and the drum gear 31 are integral, the same torque is acting. Since the tension T of the cable 9 is acting on the surface of the drum 11, the force Fg acting on the pitch circle of the drum gear 31 where the same torque is acting is

It becomes.

となる。
駆動ギア２３，２５のピッチ円に作用する力（Ｆ１＋Ｆ２）とドラムギア３１のピッチ円に作用する力Ｆｇとは、同一であるので、次の関係式が成立する。 On the other hand, the forces F1 and F2 acting on the pitch circles of the drive gears 23 and 25 are

It becomes.
Since the force (F1 + F2) acting on the pitch circle of the drive gears 23 and 25 and the force Fg acting on the pitch circle of the drum gear 31 are the same, the following relational expression is established.

このように、トルク検出器２７，２９によって駆動軸１９，２１に作用するトルクを測定することによって、ケーブル９に作用する張力を算出することができる。
なお、減速手段としてさらに減速機を介装する場合には、減速比ｉは、（Ｄｇ／Ｄｄ）×（減速機の減速比）となる。

Thus, the tension acting on the cable 9 can be calculated by measuring the torque acting on the drive shafts 19 and 21 by the torque detectors 27 and 29.
When a speed reducer is further provided as the speed reducing means, the speed reduction ratio i is (Dg / Dd) × (speed reduction ratio of the speed reducer).

In this way, the torque T1, Tr2 applied to the drive shafts 19, 21 of the electric motors 13, 15 that rotationally drive the drum 11 is detected and the tension T is calculated by detecting the directly related to the tension T of the cable 9 fed from the drum 11. Therefore, the tension applied to the cable 9 can be calculated easily and accurately.
Further, since the detection values of the torque detectors 27 and 29 are not affected by the hull motion, the tension of the cable 9 can be measured more accurately.

  Further, since the torque detectors 27 and 29 are mounted on the drive shafts 19 and 21 of the electric motors 13 and 15, drive gears 23 and 25 and a drum gear 31 as speed reduction means are interposed between the torque detectors 27 and 29. . For this reason, since the torque detectors 27 and 29 detect a torque smaller than the torque applied to the drum 11, a small torque detector can be used, and the cost of the device can be reduced accordingly.

The control device 17 calculates the tension T acting on the cable 9 from the torques Tr1 and Tr2 detected by the torque detectors 27 and 29, and when the tension T exceeds a predetermined range, the motors 13 and 15 rotate. Send a command signal to increase the number.
As a result, the rotational speed of the drum 11 is increased and the cable 9 is fed out quickly, so that the tension applied to the cable 9 is reduced.
On the other hand, when the calculated tension T of the cable 9 is a value that does not fall within the predetermined range, a command signal is sent so as to reduce the rotational speed of the motors 13 and 15.
As a result, the rotational speed of the drum 11 decreases and the cable 9 is fed out late, so that the tension applied to the cable 9 increases.

Thus, the control device 17 increases the rotation speed of the electric motors 13 and 15 when the calculated tension T of the cable 9 is determined to be an excessive tension, and the rotation speed of the electric motors 13 and 15 when it is determined that the tension is excessive. Therefore, the feeding speed of the cable 9 can be adjusted and the magnitude of the tension T applied to the cable 9 can be maintained within a predetermined range. For this reason, since the abnormal tension T is not applied to the cable 9, damage to the cable 9 can be prevented.
Thereby, the cable laying ship 1 can lay the cable 9 reliably.

  The torque detectors 27 and 29 can be removed if the shaft coupling between the drive shaft 19 and the first gear 35 and the shaft coupling between the drive shaft 19 and the second gear 37 are removed. Maintenance can be easily performed by stopping and removing the torque detectors 27 and 29.

In the present embodiment, the drums 11 are driven by two motors 13 and 15, but this may be driven by one or three or more. .
Further, even when a plurality of units are provided, some of them may be driven and the remaining units may be reserved.

Moreover, in this embodiment, although the electric motor is used as a rotational drive means, this is good also as various engines, such as a hydraulic motor and a diesel engine.
Furthermore, in the present embodiment, the phase difference detection type is used as the torque detectors 27 and 29, but a strain gauge type, a magnetic type, or the like may be used.

It is a fragmentary side view which fractures | ruptures and shows a part of cable laying ship concerning one Embodiment of this invention. It is a top view showing a schematic structure of a cable engine concerning one embodiment of the present invention. It is a side view showing a schematic structure of a cable engine concerning one embodiment of the present invention. It is a front view showing a schematic structure of a torque detector concerning one embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cable laying ship 5 Cable engine 7 Sheave 9 Cable 11 Drum 13, 15 Electric motor 17 Controller 19, 21 Drive shaft 23, 25 Drive gear 27, 29 Torque detector 31 Drum gear

Claims (4)

A drum that feeds the cable to the sheave provided at the ship end;
Rotation driving means for rotating the drum;
A torque detector mounted on the drive shaft of the rotational drive means;
A cable engine characterized by being provided with. A speed reduction means is interposed between the drum and the rotation driving means,
The cable engine according to claim 1, wherein the torque detector is attached to a drive shaft on the rotation drive means side.   2. A control device for calculating a tension of the cable from a torque value detected by the torque detector and controlling the number of rotations of the rotation driving means according to the magnitude of the tension. Or the cable engine of Claim 2. A cable laying ship equipped with the cable engine according to any one of claims 1 to 3.

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