JP2586365Y2 - Hydraulic cylinder - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a hydraulic cylinder having a long pipe for forming an oil passage therein.

[0002]

2. Description of the Related Art Various types of long hydraulic cylinders used for extending and retracting a boom of a truck crane have been conventionally proposed. For example, a conventional hydraulic cylinder shown in FIG. Has two long pipe bodies P1 and P2 for forming an oil passage inside.

That is, in the hydraulic cylinder, a rod 2 inserted into and out of a cylinder 1 has a hollow structure, and the two long pipes P
1 and P2 are arranged in a parallel state.

[0004] At the tip of the rod body 2, a piston body 3 is slidably housed in the cylinder body 1 and formed in the cylinder body 1 to form two oil chambers A and B in series. .

A base end of a cylinder tube 11 constituting the cylinder body 1 and slidingly contacting the piston body 3 is sealed with a bottom member 12, and although not shown, an open end of the cylinder tube 11 is a shaft sealing member. It is sealed.

[0006] The shaft core of the shaft sealing member is connected to the rod body 2.
Is slidably penetrated.

[0007] The one pipe body P1 is disposed on the axis of the rod tube 21 and the tip thereof penetrates the axis of the rod end member 22 and is connected to the end of the rod end member 22. It is fixed and opens to the oil chamber B.

The other pipe body P2 is arranged in parallel with the one pipe body P1 in the rod tube 21, and the tip of the other pipe body P2 penetrates the partition member 23 and is fixed to the end of the partition member 23. It is open to a chamber C formed between the partition member 23 and the rod end member 22.

The partition member 23 is disposed so as to seal the open end of the rod tube 21, and the rod end member 2
2 is connected to the partition member 23, and the rod end member 22
A piston body 3 is interposed on the outer periphery of the body.

The rod end member 22 has a horizontal hole 22.
a is opened to allow communication between the chamber C and the oil chamber A.

Although not shown, the rear end of the rod tube 21 is sealed with a rod head member.

On the other hand, the one pipe body P1 and the other pipe body P2 are held by the supporter 4 in the rod body 2, that is, in the rod tube 21, in order to prevent the bending thereof.

The supporter 4 is formed in the shape of a disk, and has one axially penetrating one pipe P1 and the other eccentric position penetrating the other pipe P2. A rubber pad 41 is interposed on the outer periphery.

Therefore, in this conventional hydraulic cylinder, each of the pipe bodies P1 and P2 is connected to an external hydraulic supply / discharge source (not shown), so that each of the oil chambers A and B has The hydraulic pressure can be controlled, and the hydraulic cylinder can be expanded and contracted.

That is, by supplying the oil pressure to the oil chamber A, the hydraulic cylinder can be contracted, and by supplying the oil pressure to the oil chamber B, the hydraulic cylinder can be extended.

Even if the hydraulic cylinder is used, for example, in a horizontal position, the intermediate portion of each of the pipes P1 and P2 can be held by the supporter 4 in the rod 2. Bending can be prevented in advance.

[0017]

However, the following problems have been pointed out in the conventional hydraulic cylinder described above.

That is, in the conventional hydraulic cylinder described above, two long pipes P1 and
Since P2 is set so as to be accommodated in a parallel state, when the diameter of the rod tube 21 forming the rod body 2 is reduced, the effective cross-sectional area serving as a flow path is secured. The piping of each of the pipe bodies P1 and P2 is not easy.

If the diameter of the rod tube 21 is reduced, the pipes P1, P2 are reduced in diameter. If the diameter of the pipes P1, P2 is reduced, the effective cross-sectional area of the pipes P1, P2 cannot be secured. The inconvenience of increasing the so-called pressure loss in each of the pipe bodies P1 and P2 is caused.

In the conventional hydraulic cylinder, the pipe body P1 is connected to the rod end member 22 and the partition member 23, the pipe body P2 is connected to the partition member 23, the partition member 23 is connected to the rod tube 21 and the rod end. The connection with the member 22 is realized by welding portions (indicated by reference numerals M1 to M5 in the drawing), and each of these welding portions M1
To M5 are all present in the oil.

Therefore, there is a risk that rust or welding slag from each of the welding portions M1 to M5 may be mixed into the oil, and if the rust or welding slag is mixed into the oil, the oil may be contaminated. However, there is a disadvantage that the length is easily increased.

Further, in order to prevent the above-mentioned rust and welding slag from being mixed in the oil, it is necessary to finish all the welding portions M1 to M5, and the number of working steps is increased, and the production of the hydraulic cylinder is increased. There is an inconvenience that cost reduction cannot be expected.

Further, in the above-mentioned conventional hydraulic cylinder, a rubber pad 41 having a concave cross section and having an annular shape is interposed on the outer periphery of the supporter 4 for preventing the pipe bodies P1 and P2 from being bent in the rod body 2. However, the rubber pad 41 is manufactured by raising a so-called mold.

Therefore, whenever the inner diameter of the rod tube 21 constituting the rod body 2 is different, it is necessary to prepare a rubber pad 41 having a different diameter by raising a so-called mold each time, thereby reducing the manufacturing cost of the hydraulic cylinder. There is an inconvenience that it is not possible to expect the conversion.

The present invention has been made in view of the above-mentioned circumstances, and has as its object that there is no fear of causing so-called pressure loss or oil contamination at the time of operation, and the manufacturing cost can be reduced. It is to provide a hydraulic cylinder that is optimal to make it possible.

[0026]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the construction of the present invention comprises a cylinder, a hollow rod which is inserted into and retractable from the cylinder, and a connection to the rod. A piston body that slides in the cylinder body and defines two oil chambers in the cylinder body, and two pistons that are housed in the rod body and form oil passages that respectively communicate with the two oil chambers. And a long pipe body, wherein the piston body is screwed to the tip of the rod body with the interposition of a sealing member, and one of the long pipe bodies is the shaft core of the rod body. And one end of the long pipe body is press-fitted into the piston body with the intervention of a sealing member, and is fitted to the shaft core of the one long pipe body. While the other long pipe body is installed The tip of the pipe body of elongated said other is press-fitted into the piston body interposed under sealing member, and the O-ring is formed by interposed on the outer periphery of the supporter.

The two long pipe bodies have their base ends connected to an external hydraulic supply / discharge source, and one long pipe body is connected to one oil chamber, for example, a rod-side oil chamber. Communicated,
The other long pipe body is communicated with the other oil chamber, that is, the piston-side oil chamber.

[0028]

Therefore, the connection of the piston body to the rod body is realized by a screwing structure with the interposition of the sealing member, and the connection of the tip of each pipe body to the piston body is realized by the press-fitting structure with the interposition of the sealing member. As a result, there is no welded portion existing in the oil.

Further, since the other pipe body is built in one pipe body, even if the rod body is made to have a small diameter, two pipe bodies, that is, one pipe housing the other pipe body. There is no effect on the piping of the body, and it is easy to secure an effective cross-sectional area in each pipe body.

By providing an O-ring on the outer periphery of the supporter, it is easy to obtain an O-ring having a desired diameter even when the diameter of the supporter is changed. It saves you the trouble of getting up.

The oil pressure from the hydraulic supply / discharge source is supplied to one oil chamber, for example, a rod-side oil chamber, through one long pipe body, and the oil in the piston-side oil chamber is supplied to the other oil chamber. The hydraulic cylinder is contracted when it is returned to the hydraulic supply / discharge source via the measuring pipe.

The hydraulic pressure from the hydraulic supply / discharge source is supplied to the other oil chamber, that is, the piston-side oil chamber, through the other long pipe body, and the oil in the rod-side oil chamber is supplied to the other oil chamber. The hydraulic cylinder is extended when it is returned to the hydraulic supply / discharge source via the measuring pipe.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment shown in the drawings. The hydraulic cylinder according to this embodiment has basically the same structure as the conventional hydraulic cylinder shown in FIG. I have.

Accordingly, parts having the same configuration are denoted by the same reference numerals in the drawings, and detailed description thereof will be omitted. Hereinafter, different parts in this embodiment will be mainly described.

That is, in the hydraulic cylinder shown in FIG. 1, two long pipe bodies P1 and P2 housed in a rod body 2 that can be inserted into and retracted from the cylinder body 1 are connected to one of the pipe bodies. It is characterized in that it is arranged in a so-called double pipe structure in which the other pipe body P2 is inserted into P1.

The rod body 2 is a rod tube 21
The piston body 3 is directly connected to the tip of the hollow structure, and the partition member 23 (see FIG. 2) and the rod end member 2 are provided as in the above-described conventional example.
2 (see FIG. 2).

The connection of the piston body 3 to the rod body 2, ie, the rod tube 21, is realized by a screwing structure with the intervention of the sealing member 5, and the connection of the tip of one pipe body P1 to the piston body 3 is realized. It is also characterized in that the press-fitting structure is realized with the interposition of the seal member 6 and the continuous connection of the tip of the other pipe body P2 to the piston body 3 with the interposition of the seal member 7.

The piston body 3 has a rod body 2, ie, a rod tube 21, on the inner periphery at one end which is the upper side in the figure.
In the figure, a screw 3a is screwed into a screw 21a formed on the outer periphery of the lower end.

The piston body 3 has a recess 3b which is open at the lower end surface of the piston body 3 and communicates with the other oil chamber, ie, the piston side oil chamber B, at the other end, which is the lower side in the figure. In addition, a lateral hole 3c which is opened at a middle portion on the side surface of the piston body 3 and communicates with one oil chamber, that is, the rod-side oil chamber A.
Having.

The piston body 3 is provided with a piston ring 31 and a seal member 32 slidably contacting the outer circumferential surface of the piston body 3 on the inner circumferential surface of the cylinder tube 11 constituting the cylinder body 1.

Incidentally, the state in which the piston body 3 is connected to the rod body 2 is maintained by a detent pin 33 disposed between the two.

By the way, the two pipes P1 and P2 whose tips are connected to the piston 3 in a press-fitting structure are arranged in the rod 2 in a so-called double-pipe structure. Is explained a little.

That is, one pipe P1 is positioned at the axis of the rod 2, and the other pipe P2 is positioned at the axis of the one pipe P1.

Therefore, in the illustrated example, the two pipes P1 and P2 are arranged in the rod 2 in a so-called double pipe structure having a concentric structure.

As long as a so-called double-pipe structure is used, the other pipe body P2 may be inserted so as to be eccentric to one pipe body P1.

The one end of the pipe body P1 is press-fitted into a recess 3d formed in the shaft core on the upper end side of the piston body 3 with the sealing member 6 interposed therebetween, and opens into the recess 3d. ing.

On the other hand, the other end of the pipe body P2 is press-fitted into a through hole 3 formed at the lower end side shaft core of the piston body 3 with a sealing member 7 interposed therebetween. 3
It is open to.

The recess 3d communicates with the lateral hole 3c, and the through hole 3 communicates with the recess 3b.

The two pipes P1 and P2 have their base ends connected to an external hydraulic supply / discharge source (not shown), and one pipe P1 has a rod-side oil chamber serving as one oil chamber. Of course, the other pipe body P2 is communicated with the chamber A, and the other pipe body P2 is communicated with the piston-side oil chamber B, which is the other oil chamber.

The two pipes P1 and P2 are housed in the rod body 2 and the intermediate part thereof is the supporter 4
However, it is assumed that an annular groove 4a having a concave cross section is formed on the outer periphery of the supporter 4, and an O-ring 8 as a cushion member is interposed in the annular groove 4a. .

The reason why the O-ring 8 is interposed on the outer periphery of the supporter 4 as described above is that a manufacturer of this type of hydraulic cylinder always prepares O-rings 8 having different diameters. Usually, therefore, even when the diameter of the supporter 4 is changed, it is easy to obtain the O-rings 8 having different diameters and only to interpose the O-rings 8 having different diameters on the outer periphery of the supporter 4. It will be enough.

Therefore, in the hydraulic cylinder according to this embodiment formed as described above, the continuous connection of the piston body 3 to the rod body 2 is realized by a screwing structure with the seal member 5 interposed therebetween. Since the end of each of the pipe bodies P1 and P2 is connected to the piston body 3 by a press-fitting structure with the seal members 6 and 7 interposed therebetween, there is no welding portion existing in the oil.

Further, by assuming that the other pipe body P2 is built in one pipe body P1, the rod body 2,
That is, even if the rod tube 21 is made to have a small diameter, the two pipe bodies P1 and P2 can be easily accommodated in the rod tube 21. Therefore, it is easy to secure an effective sectional area in each of the pipe bodies P1 and P2. become.

Since the O-ring 8 is interposed on the outer periphery of the supporter 4, even if the diameter of the supporter 4 is changed, it is easy to obtain the O-ring 8 having a desired diameter. Sufficient, so-called type rework is saved.

The oil pressure from the oil pressure supply / discharge source is supplied to the rod-side oil chamber A as one oil chamber via one pipe body P1, and the oil in the piston-side oil chamber B is supplied to the other pipe body P1.
The hydraulic cylinder is contracted when returned to the hydraulic supply / discharge source via 2.

Further, the oil pressure from the oil pressure supply / discharge source is supplied to the piston side oil chamber B as the other oil chamber via the other pipe body P2, and the oil in the rod side oil chamber A is supplied to the one pipe body P1. The hydraulic cylinder is extended when returned to the hydraulic supply / discharge source via.

[0057]

[Effect of the Invention] As described above, according to the present invention, since there is no welding portion existing in the oil, the chance of oil contamination is greater than when there is a welding portion existing in the oil. And the durability of the hydraulic cylinder is increased.

Further, according to the present invention, the two pipes can be easily accommodated in the rod even when the diameter of the rod tends to be small, and the effective sectional area of each pipe is reduced. There is an advantage that securing is easy.

According to this invention, even if the diameter of the rod body for accommodating the long pipe body is changed, the cushion member can be easily and inexpensively mounted on the outer periphery of the supporter for preventing the pipe body from being bent. There is an advantage that it is possible to interpose.

Therefore, according to the present invention, it is possible to provide a hydraulic cylinder capable of reducing manufacturing costs without fear of causing so-called pressure loss or oil contamination during operation.

[Brief description of the drawings]

FIG. 1 is a partial longitudinal sectional view showing a hydraulic cylinder according to an embodiment of the present invention.

FIG. 2 is a partial longitudinal sectional view showing a hydraulic cylinder as a conventional example, similarly to FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder body 2 Rod body 3 Piston body 4 Supporter 5, 6, 7 Sealing member 8 O-ring A Rod-side oil chamber as oil chamber B Piston-side oil chamber as oil chamber P1, P2 Pipe body

Claims (1)

(57) [Scope of request for utility model registration] 1. A cylinder body, a rod body having a hollow structure which is inserted into and retractable from the cylinder body, and is connected to the rod body and slides in the cylinder body, and defines two oil chambers in the cylinder body. In a hydraulic cylinder having a piston body to be formed, and two long pipe bodies housed in the rod body and forming oil passages respectively communicating with the two oil chambers, the piston body is One long pipe body is screwed to the tip of the rod body with the interposition of a sealing member, and one long pipe body is disposed at the shaft core of the rod body with the supporter interposed, and the one long pipe body is The tip of the body is press-fitted into the piston body with the interposition of a sealing member, and the other long pipe body is housed in the axial core of the one long pipe body and the other long pipe body is accommodated. The tip of the pipe body is a piston body with the sealing member A hydraulic cylinder characterized by being press-fitted into a cylinder and having an O-ring interposed on the outer periphery of the supporter