JPH0346356B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a bearing device for supporting a turret in a turret-mulling ship.

[Conventional technology]

Undersea oil fields are being developed around the world in deep-water areas, areas with poor sea conditions, or abandoned areas due to low reserves. So-called turret muling ships are attracting attention.
As shown in FIG. 2, in this ship, a turret 100 having a cylindrical shape and having a flange 101 (deck part) on the outside of the upper part is inserted into a through hole 110 formed through the center of the hull 120. Upper through hole 1
A bearing device consisting of a plurality of wheels 130 that can be raised and lowered is provided around the turret 10, and the turret 100 is rotatably supported by the bearing device via its collar 101, and the turret 100 is equipped with a mooring cable 140 and an anchor 141. It has a structure with multiple sets of mooring devices. This ship has a mooring line 140 and an anchor 141 attached to a turret 100.
The turret 100 is fixedly moored directly above the oil well by lowering it radially from the well, and excavation or the like is performed using an oil country pipe lowered through the inside of the turret 100.

When mooring a ship, the relationship between the direction of sea conditions such as tidal currents, wind, and waves and the direction in which the ship is facing has a large effect on the mooring force.

When drilling offshore oil fields using a turret mooring vessel, which is forced to stay moored for a long period of time, the sea conditions in the surrounding sea area change significantly during mooring. The hull 120 is rotatable around the turret 100, and by changing the direction of the hull 120, the external force that the hull 120 receives from tides, wind, and waves can be minimized, and the mooring force applied to the mooring line 140 can be reduced. ing.

When the sea conditions are calm for a large portion of the time, the external forces exerted on the hull 120 from tidal currents, wind, and waves are small, and the mooring force applied to the mooring lines 140 is also small (generally, the direction of the tidal current is also stable). ,
Turn the turret 10 with the hull 120 facing the direction of the current.
0 and lower the hull 12 as shown in Figure 2b.
The turret 100 and the hull 12
Leave it fixed at 0. Even if the tidal current changes, the mooring cables 140 extending radially in all directions from the turret 100 may
When the turret 100 is twisted to some extent due to the turning of the mooring rope 100, the bearing device is used to raise it so that it can rotate to the original position, and the brake/drive unit is used to rotate the turret 100. A modification is made to return the turret 100 to rotation.

On the other hand, when sea conditions become severe due to the approach or passage of a low pressure system, the external force acting on the hull 120 due to wind and waves increases, so the turret 10
0 is raised and the turret 100 is supported by a bearing device as shown in FIG. By doing so, the mooring force applied to the mooring line 140 is reduced, and safe mooring is possible (according to many observational results, the directions of strong winds and large waves generally coincide).

By raising and lowering the turret 100 in this way, we aim to reduce the usage time of the bearing device, ensure reliable operation over a long period of time, and reduce maintenance and inspection work. If left in use, the life of the bearing will be extremely shortened, and if the turret has a locking mechanism when working near the turret, the worker will be able to do the work safely. need to be considered).

By the way, the above-mentioned bearing device for supporting the turret has a structure as shown in FIG. 3 to raise and lower the wheel 130. That is, the wheel 130 is rotatably attached to a two-point support frame 131, one end of the frame 131 is supported by the tip of a support 132 set up on the hull deck 121, and the other end of the frame 131 is mounted on the same hull deck. The frame 131 is attached to the tip of a rod 134 of a hydraulic cylinder 133 hanging vertically above the frame 121, and by expanding and contracting the rod 134 of the hydraulic cylinder 133, the frame 131 is rotated as shown by the arrow, and the wheel 130 is raised and lowered. ing.

[Problem that the invention seeks to solve]

Turret 1 on a turret muling ship
The load acting on the bearing device for supporting the turret 100 is not only the vertical load due to the weight of the turret 100 itself [and the mooring line 140] [and the lateral component of this load caused by the motion of the hull 120], but also the rotation of the turret 100. There are horizontal loads such as thrust loads (or lateral loads for transmitting external forces acting on the hull 120 due to tidal currents, wind, and waves to the mooring lines 140).

In the bearing device shown in FIG.
31, the hydraulic cylinder 133 side supports the axial load, that is, the vertical load on the cylinder side,
On the support 132 side, a vertical load is supported, and a horizontal load (thrust load or lateral load) also acts on the pivot points of the support 132 of the frame 131 (Figure 3 shows the forces acting on these points). Therefore, the bearing device must also have a structure that requires reinforcement, and therefore a large structure.

The present invention has been made to solve the above-mentioned problems, and aims to provide a new compact bearing device that does not impose unnecessary bending moments on various parts of the device.

[Means for solving problems]

Therefore, the present invention provides a bearing support, an eccentric shaft whose shaft center is pivotally supported eccentrically from the shaft support center of the bearing support, a wheel rotatably provided on the eccentric shaft, and a wheel that rotates the shaft support center. It is an object of the present invention to provide a bearing device for supporting a turret, which is constituted by a drive device for rotating a bearing support around the center.

[Effect]

The principle of such a configuration will be explained using FIGS. 1a and 1b. 1 is a bearing support, 2 is an eccentric shaft, 3 is a wheel, and 4 is a drive device.

The bearing support 1 pivotally supports an eccentric shaft 2 as described later, and A indicates the shaft support center of the bearing support 1.

The eccentric shaft 2 is pivotally supported by the bearing support 1 with its axis B being eccentric from the shaft support center A.

The wheel 3 is rotatably provided on the eccentric shaft 2.

The drive device 4 rotates the bearing support 1 about the shaft support center A as a rotation center.

With this configuration, when the bearing support 1 is rotated as shown in FIG. It will rise while drawing an arc together with the axis B. Further, the wheel 3 is lowered by the operation opposite to the above.

Therefore, in the bearing device of the present invention, since the device is compact, the vertical load and the horizontal load received by the wheel 30 are transferred to the base 11 which is integrated with the wheel 30 via the bearing support 10 and the bearing bearing 12. The bending moment is directly transmitted to each part of the device, and the hydraulic cylinder 40 is not subjected to a large vertical load.

〔Example〕

FIG. 4 shows an embodiment of the present invention, which includes a bearing support 10, an eccentric shaft 20, a wheel 30, and a drive device 40.

The bearing support 10 supports the eccentric shaft 20 with A' as the shaft support center, and is itself composed of a sleeve, and is rotatably supported by a bearing 12 erected on a base 11 on the hull deck 121. It is pivotally supported.

The eccentric shaft 20 has its axis B' as the shaft support center.
The shaft is eccentrically supported from A' by the bearing support 10, and in this embodiment passes through the sleeve-shaped bearing support 10.

The wheel 30 is rotatably mounted on the eccentric shaft 20, and is joined to the lower surface of the turret flange 101 when raised as described above, thereby making the turret 100 rotatable. This wheel 30
A through hole (not shown) is formed in the wheel, the eccentric shaft 20 is passed through the hole, and a roller bearing (not shown) is installed between the eccentric shaft 20 and the surface of the through hole of the wheel 30. Axial center of eccentric shaft 20
It is designed to be able to rotate freely around B'.

The power device 40 includes a hydraulic cylinder that rotates the bearing support 10 about the shaft support center A'. In this embodiment, the bearing support 1
A mount 41 is fixed to the end of the eccentric shaft 20 passing through the mount 41, and the tip of the rod 42 of the power device 40 is pinned to the plate 41a extending from the mount 41.
3 is rotatably pinned to a hinge 44 provided on the hull deck 121.

In the above embodiment, as shown in FIG. 5, when the rod 42 of the power unit 40 is extended, the bearing support 10 rotates within the bearing 12 with the shaft support center A' as the rotation center. As a result, the eccentric shaft 20 moves upward as its axis B' moves in an arc as shown by the arrow. Therefore, since the center point of the wheel 30 coincides with the axis B', the wheel 30 rises in an arc as shown by the arrow. On the other hand, wheel 30
When lowering the rod 42 of the drive device 40,
If the rod 42 is contracted, it will descend in the reverse order.

〔Effect of the invention〕

As explained above, according to the bearing support device of the present invention, the wheel can be supported by a simple configuration in which the axis of the shaft that pivots the wheel and the shaft support center of the support that supports the shaft are made eccentric. Because of this compact bearing support configuration, the vertical and horizontal loads received by the wheels are directly transmitted to the hull, causing unnecessary bending moments to be applied to each part of the equipment. There is no. Furthermore, since it has a compact and simple structure, it also has the advantage of being easy to construct.

[Brief explanation of drawings]

1a and 1b are explanatory views of the structure of the present invention; FIG. 2 is a schematic view showing the outline of a turret-maring ship; FIG. 3 is an explanatory view showing the structure of a conventional turret supporting bearing device; FIG. 4 is a side view showing one embodiment of the present invention, and FIG. 5 is an explanatory diagram showing the operating state of this embodiment. In the figure, 1 and 10 are bearing supports, 2 and 20 are eccentric shafts, 3 and 30 are wheels, 4 and 40 are drive devices, A and A' are shaft support centers, and B and B' are eccentric shaft centers. Each shown.

Claims (1)

[Claims] 1. A bearing support, an eccentric shaft whose shaft center is pivoted eccentrically from the shaft support center of the bearing support,
A bearing device for supporting a turret, comprising: a wheel rotatably provided on the eccentric shaft; and a drive device for rotating a bearing support about the shaft support center.