JPH0639873B2 - Controller for hydraulic cylinder for deep sea - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention operates in a high pressure environment such as a hydraulic cylinder for an excavator used for mineral extraction in the deep sea (for example, a cylinder for opening and closing a bucket of a clamshell). The present invention relates to a control device for a deep-sea hydraulic cylinder.

(Prior Art) As a method of extracting minerals in the deep sea, for example, a method shown in a research report on hydrothermal deposits (1985) [published by the Deep Sea Mineral Resources Development Association (DOMA)] is known. . In the method, a clamshell bucket is sunk into a deep sea from a work boat with a wire rope, and the bucket is opened and closed by a hydraulic cylinder in the deep sea to collect the seabed minerals.

In the above method, the control device for the hydraulic cylinder that opens and closes the bucket includes a hydraulic pump, a drive motor for the hydraulic cylinder, a valve such as a directional control valve, and other drive control system hydraulic equipment attached to the bucket support of the clamshell. A thin plate box with a lid (pressure-resistant shell) is sealed together with oil in a pressure-equalized pressure-equalizing system. The pressure of the oil filled in the box by a diaphragm or the like provided on the lid of the pressure-resistant shell ( By equalizing the inner pressure) to the outer pressure, the hydraulic equipment can be protected from seawater without damaging the pressure shell even if the pressure shell has a small strength.

However, in this device, the hydraulic cylinder is outside the pressure shell, and at the neutral position of the directional control valve, the pipes connected to the oil chambers on both sides of the hydraulic cylinder are blocked, so that the pressure equalizing action of the pressure shell is applied to the hydraulic cylinder. It has a structure that does not reach the end. For this reason, when this device is submerged in the deep sea in a neutral state of the directional control valve and placed in a high-pressure environment, the pressure in the pipeline (pipe) between the directional control valve and the hydraulic cylinder and the oil chambers on both sides of the hydraulic cylinder are The pressure difference between the pressure and the external pressure becomes large, and the rod packing of the hydraulic cylinder, the external pipe, the pipe joint, etc. may be crushed or damaged due to the pressure difference.

The working pressure of the hydraulic cylinder is generally 210 kg / cm.
External pressure in the deep sea is 400kg / c, while it is up to ²
m ² (depth 4000 m) to 1000 kg / cm ² (depth 10
000 m), the hydraulic cylinder and the like need to have a special structure (pressure resistant structure) in order to prevent the above damage from occurring even when such an external pressure is applied in the above-mentioned conventional device. Not only is it difficult to design, but the cost also increases significantly.

(Object of the Invention) The present invention has been made to solve such a problem, and ensures that the rod packing of the hydraulic cylinder, the external pipe, the pipe joint, and the like are damaged by external pressure with a simple structure. Can be prevented and the device life can be extended,
(EN) Provided is a control device for a deep-sea hydraulic cylinder that does not require the use of a special structure for the hydraulic cylinder or the like, is easy to manufacture, and can significantly reduce the cost.

(Structure of the Invention) The present invention relates to a deep-sea hydraulic cylinder control device configured to supply and discharge pressure oil from a hydraulic source to both oil chambers of the deep-sea hydraulic cylinder via a control valve. And drive control equipment such as control valves are enclosed with oil in a pressure resistant shell,
The pressure-resistant shell has a pressure equalizing portion for equalizing the external pressure and the internal pressure, the hydraulic cylinder is outside the pressure-resistant shell, and oil chambers on both sides of the hydraulic cylinder are connected to a control valve in the pressure-resistant shell by piping. At least one of the oil chambers is connected to one chamber of a free piston type pressure equalizing cylinder having two chambers separated by a free piston, and an external pressure introducing portion is provided in the other chamber of the pressure equalizing cylinder. It is characterized by that.

With this configuration, when the device is submerged in the deep sea and placed in a high-pressure environment, the internal pressure and the external pressure of the pressure-resistant shell are equalized, the internal hydraulic power source and drive control devices such as control valves are protected from the external pressure, and the pressure is equalized. The pressure cylinder equalizes the internal pressure and external pressure on the hydraulic cylinder side to protect the hydraulic cylinder, and this pressure equalization compensates for the compression of the oil inside the cylinder, allowing the hydraulic cylinder to operate at its original operating pressure. Therefore, it is not necessary to use a special structure for the hydraulic cylinder and its accessories such as packing and piping, and the conventional ordinary land-based one can be used as it is.

(Embodiment) FIG. 4 shows a deep-sea clamshell as an example of a working machine to which the present invention is applied. In this figure, a pair of buckets 2 are provided at the bottom of the bucket support 1 and pivots 3 respectively.
The buckets 2 are rotatably supported via the, and both buckets 2 are rotated and opened / closed by a working hydraulic cylinder 4. A wire rope 6 is connected to an upper portion of the bucket support 1 via a hanging fitting 5, and the wire rope 6 is wound up on a winch equipped on a work boat (not shown).

In the clamshell, a pressure-resistant shell 7 is attached to the bucket support 1, and a hydraulic drive control device as shown in FIG. 1 is installed in the pressure-resistant shell 7 to drive the hydraulic cylinder 4.

FIG. 1 is a hydraulic circuit diagram showing an embodiment of the present invention. First
In the figure, the pressure-proof shell 7 is formed in a box shape from a thin steel plate or the like, and a pressure equalizing portion 8 such as a diaphragm is provided at a predetermined position thereof. The pressure-resistant shell 7 is attached to the bucket support 1 shown in FIG. 4 so as not to interfere with the expansion and contraction of the hydraulic cylinder 4 and the rotation of the bucket 2.

In the pressure-resistant shell 7, a hydraulic pump 9 as a hydraulic source, an electric motor 10 for driving the hydraulic pump 9, and a main relief valve 1 are provided.
1, directional control valve 12, overload relief valve 13,
A hydraulic drive control device consisting of 14 control valves and the like is enclosed together with oil to form a so-called oil-equalized pressure equalizing system. Reference numeral 15 is a power source such as a battery, and 16 is a drive switch of the motor 10, which is turned on / off by an operation signal from an operation signal line 17. The power source 15 such as the battery and the drive switch 16 may be housed in the pressure-resistant shell 7 and provided on the clamshell side, or may be provided on the work boat side (not shown).

As the directional control valve 12, an electromagnetic switching valve or an electromagnetic hydraulic switching valve that is switched by an electric signal from the operation signal line 17 is used, and the directional control valve 12 and the head side oil chamber 4a of the hydraulic cylinder 4 and the rod side are used. The oil chamber 4b is connected by the pipe lines 18 and 19.

Reference numeral 20 is a free piston type pressure equalizing cylinder, in which a free piston 21 slidable in the axial direction is inserted,
Of the two chambers 22 and 23 in the cylinder that are separated by the free piston 21, one chamber 23 is connected to the head side oil chamber 4a of the hydraulic cylinder 4 and is connected to the other chamber 2
2 is provided with an external pressure introducing portion 24 that opens to the outside.
Reference numeral 25 is a return spring for the free piston 21.

Next, the operation of the above configuration will be described.

First, at sea, an on signal is sent from a work boat (not shown) to the drive switch 16 via the operation signal line 17, and the switch 16 is turned on to drive the motor 10 to drive the pump 9 and the pump 9 The oil enclosed in the pressure-resistant shell 7 is guided to the direction control valve 12.
In this state, when the directional control valve 12 is switched to the lower position by a signal from the operation signal line 17, the oil discharged from the pump 9 passes from the directional control valve 12 through the conduit 18 to the rod side oil chamber 4b of the hydraulic cylinder 4. The cylinder 4 is contracted, and the oil in the head-side oil chamber 4a is returned to the pressure-resistant shell 7 via the conduit 19 and the direction control valve 12. Along with this, the hydraulic cylinder 4 is contracted, and the bucket 4 (fourth
(See figure) is opened. At this time, the head side oil chamber 4a
The oil inside flows into the chamber 23 of the pressure equalizing cylinder 20, and the free piston 21 is moved to the left stroke end.

Then, the directional control valve 12 is returned to the neutral position, and the pipe 18,
Blocking 19 keeps the hydraulic cylinder 4 compressed and the bucket 2 open.

Next, with the hydraulic cylinder 4 contracted and the bucket 4 open, the wire rope 6 of FIG. 4 is unwound by a winch provided on a work boat (not shown), so that the bucket 2 is sunk to the seabed. At this time, the motor 10 or the pump 9 may remain driven, but the switch 16
The power can be saved by turning off the switch and turning the bucket 2 down while the motor 10 and the pump 9 are stopped.

In this way, when the bucket 2 is submerged in the seabed, the hydraulic cylinder 4, the pressure equalizing cylinder 22 attached thereto and the hydraulic equipment provided in the pressure-resistant shell 7 are also submerged integrally with the bucket 2, and the depth thereof increases. Accordingly, a large water pressure (external pressure) acts on the outside of the pressure resistant shell 7. However, at this time, the external pressure also acts on the pressure equalizing portion 8 provided at a predetermined position of the pressure resistant shell 7, and the oil enclosed in the pressure resistant shell 7 is compressed by the pressure equalizing portion 8, and the pressure of the internal oil ( The inner pressure is equalized to the outer pressure. This prevents the pressure-resistant shell 7 from being crushed by the external pressure even if the pressure-resistant shell 7 is sunk together with the bucket 2 to a deep sea of several thousand m, and the pressure-resistant shell 7 prevents the internal motor 10, pump 9, and valves. Hydraulic equipment such as 11, 12, 13, and 14 is protected from seawater, and the life of the equipment is improved.

On the other hand, on the hydraulic cylinder 4 side, since the directional control valve 12 is in the neutral position, the pipelines 18 and 19 are blocked, and the pressure equalizing action of the pressure resistant shell 7 does not reach the hydraulic cylinder 4. However, at this time, external pressure (water pressure) also acts on the chamber 22 on the left side of the drawing from the external pressure introducing portion 24 of the pressure equalizing cylinder 20, and the free piston 21 is pressed to the right by the external pressure. Along with this, the oil in the chamber 23 on the right side of the pressure equalizing cylinder 20, the oil in the head side oil chamber 4a of the hydraulic cylinder 4 communicating with this, and the oil in the pipeline 19 are also compressed, and their pressure (internal pressure) ) Is equalized to be equal to the external pressure, and the oil in the rod side oil chamber 4b and the oil in the pipe line 18 are also compressed via the piston 4c in the hydraulic cylinder 4, and their pressure (internal pressure)
Is also equalized so as to be equal to the external pressure. That is, the oil chambers 4a, 4b on both sides of the hydraulic cylinder 4 and the conduit 18,
Each internal pressure of 19 is also equalized so as to be equal to the external pressure,
Therefore, it is possible to prevent the packing, the piping, the joint and the like of each part of the hydraulic cylinder 4 from being crushed or damaged by the pressure difference between the external pressure and the internal pressure.

Next, at the time of excavation in the deep sea, with the switch 16 turned on to drive the motor 10 and the pump 9,
When the directional control valve 12 is switched to the upper position, the oil discharged from the pump 9 is guided to the head side oil chamber 4a of the hydraulic cylinder 4 through the directional control valve 12 and the pipe 19, and is also introduced into the chamber 23 of the pressure equalizing cylinder 20. The pressure (internal pressure) in each chamber 4a, 23 gradually rises. Then, the internal pressure becomes higher than the external pressure acting on the other chamber 22 of the pressure equalizing cylinder 20, and after the free piston 21 moves to the left stroke end, the hydraulic cylinder 4 is moved by the differential pressure between the internal pressure and the external pressure. Is extended, the oil in the rod side oil chamber 4b is returned to the pressure resistant shell 7 through the pipe line 18 and the direction control valve 12, and the cylinder 2 is extended to close the bucket 2. Further, when the directional control valve 12 is switched to the lower position, the hydraulic cylinder 4 is operated by the same operation as described above.
Is contracted and the bucket 2 is opened. In this way, by expanding and contracting the hydraulic cylinder 4 and opening and closing the bucket 2,
Mining of the seabed and other excavation work will be performed.

In this case, the pressure on the suction side of the pump 9 and the pressure on the return oil side from the directional control valve 12, that is, the tank pressure is equalized with the external pressure by the pressure equalizing action by the pressure resistant shell 7 and the pressure equalizing action by the pressure equalizing cylinder 20. The cylinder 4 can be expanded and contracted sufficiently smoothly only by increasing the internal pressure of the head-side oil chamber 4a or the rod-side oil chamber 4b of the hydraulic cylinder 4 by a pressure difference corresponding to the original operating pressure with respect to the external pressure. Can be made. That is, the hydraulic cylinder 4 can be operated by the original working pressure regardless of the external pressure, and therefore, it is not necessary to adopt a special pressure resistant structure for the hydraulic cylinder 4.

Next, after the work in the deep sea is completed, for example, the hydraulic cylinder 4
And the bucket 2 is closed and the directional control valve 12 is returned to the neutral position. When this device is levitated, the pipelines 18 and 19 are blocked at the neutral position of the directional control valve 12, so In the oil chambers 4a and 4b on both sides of the hydraulic cylinder 4 that has been compressed for equalizing the external pressure and the pressure of
The pressure difference between the internal pressure of the oil in 8 and 19 and the external pressure thereof gradually increases as the external pressure decreases, but the increase in the differential pressure is increased by the overload relief valves 13 and 14 on the tank side, that is, the pressure shell. Missed in 7. Therefore, there is no possibility that the hydraulic cylinder 4 and the conduits 18 and 19 will be expanded and damaged.
On the pressure-resistant shell 7 side, regardless of the level of external pressure,
The pressure equalizing portion 8 equalizes the internal pressure and the external pressure so that the internal pressure and the external pressure are always equalized, so that there is no fear that the pressure-resistant shell 7 will be expanded and damaged by floating.

By the way, in the above embodiment, the pressure equalizing cylinder 20 is connected to the head side oil chamber 4a of the working hydraulic cylinder 4,
You may connect with the rod side oil chamber 4b.

Further, in the above embodiment, when the device is submerged in the deep sea, when the external pressure is introduced into the chamber 22 of the pressure equalizing cylinder 20 for the pressure equalization on the cylinder side, the free piston 21 is moved to the right side and the hydraulic pressure is increased. The oil in the head-side oil chamber 4a of the cylinder 4 and the oil in the rod-side oil chamber 4b are compressed, and the piston 4c is slightly moved to the right by the compression of this oil. As shown in FIG. 2, the pressure equalizing cylinder 2 is provided in both the head side oil chamber 4a and the rod side oil chamber 4b.
Connect 0. In this way, both the head-side oil chamber 4a and the rod-side oil chamber 4b are pressure-equalized simultaneously, so that the piston 4c does not move during pressure equalization.

Further, as shown in FIG. 3, a pressure equalizing portion (external pressure introducing portion) 26 such as a diaphragm is provided in an external pressure introducing opening provided in one chamber 22 of the pressure equalizing cylinder 20, and oil is sealed in the interior thereof. Good. By doing so, the external pressure is received by the pressure equalizing portion 26, and the free piston 21 is moved through the oil in the chamber 22 to exert a pressure equalizing action, so that seawater or the like does not enter the pressure equalizing cylinder 20. The corrosion of the pressure equalizing cylinder 20 can be prevented and the life of the cylinder 20 can be extended, and at the same time, the free piston 21 can be prevented from rusting, malfunction, etc., and the pressure equalizing action can be properly exerted.

(Effects of the Invention) As described above, according to the present invention, when working in a high-pressure environment such as deep sea, the pressure equalizing portion provided in the pressure-resistant shell can equalize the internal pressure and the external pressure in the pressure-resistant shell. The pressure-resistant shell is not damaged by external pressure, and the hydraulic equipment inside the pressure-resistant shell can be reliably protected from seawater, etc., and at the same time on the working hydraulic cylinder side, the free piston type pressure equalizing cylinder equalizes the internal pressure and the external pressure. Even if the directional control valve is in the neutral state and is in the block state, it is possible to reliably prevent the rod packing of the hydraulic cylinder, the external piping, the pipe joint, etc. from being damaged by the external pressure even if the directional control valve is in the neutral state. The device life can be extended. Moreover, just by equipping the working hydraulic cylinder with a pressure equalizing cylinder, the pressure equalizing action compensates for the amount of compression of the oil inside the cylinder due to the external pressure, and the hydraulic cylinder can operate only with the original working pressure. It is not necessary to use a special structure for the cylinder, its packing, accessories such as piping, etc., and the conventional ordinary land type can be used as it is, and it is easy to manufacture and a large cost reduction can be achieved.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram showing an embodiment of the present invention, and FIGS. 2 and 3 are hydraulic circuit diagrams of a main part showing another embodiment, respectively.
FIG. 4 is a front view showing an example of a deep-sea clamshell to which the device of the present invention is applied. 1 ... Bucket support, 2 ... Bucket, 4 ... Working hydraulic cylinder, 6 ... Wire rope, 7 ... Pressure-resistant shell, 8
...... Equalizing part, 9 ...... hydraulic pump, 10 ...... electric motor for driving pump, 11 ...... main relief valve, 12 ...... direction control valve, 13, 14 ...... overload relief valve, 1
8, 19 ... Pipe line, 20 ... Free-piston type pressure equalizing cylinder, 22, 23 ... Chamber, 24 ... External pressure introducing section, 25
...... Spring for free piston return, 26 …… Pressure equalizing part (external pressure introducing part).

Claims (1)

[Claims] 1. A controller for a deep-sea hydraulic cylinder configured to supply and discharge pressure oil from a hydraulic source to both oil chambers of the deep-sea hydraulic cylinder via a control valve, wherein the hydraulic source and the control valve, etc. Drive control device is enclosed in a pressure-resistant shell together with oil, and the pressure-resistant shell has a pressure equalizing section for equalizing the external pressure and the internal pressure. The hydraulic cylinder is outside the pressure-resistant shell, and the oil chambers on both sides of the hydraulic cylinder are pressure-resistant shells. Is connected to the control valve inside by a pipe, and at least one oil chamber of this hydraulic cylinder is connected to one chamber of a free-piston type pressure equalizing cylinder having two chambers separated by a free piston, for equalizing pressure. An apparatus for controlling a deep-sea hydraulic cylinder, wherein an external pressure introducing portion is provided in the other chamber of the cylinder.