JPH0540080Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a cylinder equipped with a down control valve used in forklifts and the like.

(Conventional technology) Forklifts use a pair of cylinders,
Both cylinders are synchronized to horizontally move the load up and down. When a failure occurs in the piping or the like of one of these cylinders, the load is supported only by the other cylinder.

In addition to synchronizing both cylinders as described above, it is recommended to provide a down control valve on the bottom side of at least one cylinder in order to be able to support the load with just one cylinder in the event of a failure or other situation. Normal.

FIG. 2 shows a conventional cylinder equipped with such a down control valve.

In the first cylinder _S1 shown in FIG. 2, the bottom portion of the cylinder body 1 is thickened, and the valve case 3 of the down control valve V is inserted into the thickened portion 2. A protrusion 4 that projects upward along the cylinder body 1 is formed in the thick portion 2, and a supply/discharge port 5 is formed in the protrusion 4. A switching valve 7 is connected to the supply/discharge port 5 via a passage 6.

Now, switch the switching valve 7 and connect the above supply/discharge port 5.
When pressure oil is supplied to the control orifice 9, this pressure oil flows into the relay chamber 10 from the control orifice 9. This relay room 10
The pressure oil flowing into is supplied to the bottom side chamber 12 of the first cylinder S ₁ through the first detection orifice 11, and is also supplied to the bottom side chamber 14 of the second cylinder S ₂ through the second detection orifice 13. will also be supplied.

When both cylinders S ₁ and S ₂ are raised in this manner, when the switching valve 7 is switched to connect the supply/discharge port 5 to the tank, both cylinders begin to descend, but the oil flow path at that time is is as follows.

That is, the oil in the bottom chamber 14 of the second cylinder S ₂ is depressurized by the second detection orifice 13 and flows into the relay chamber 10 . At the same time, the oil in the bottom side chamber 3 of the first cylinder _S1 flows into the relay chamber 10 through the first detection orifice 11, but when this oil passes through the first detection orifice 11,
A differential pressure occurs before and after that. This differential pressure is led to the pressure chamber 16 through the check valve 15, so that the spool 17 moves against the spring 18. When the spool 17 moves in this manner, the control orifice 9 is slightly closed, and the descending speed of the cylinder is controlled in accordance with its opening degree.

(Problems to be Solved by the Present Invention) In the conventional cylinder as described above, the thick wall portion 2 is provided at the bottom portion, and the supply/discharge port 5
A protrusion 4 for forming the above-mentioned thick portion 2 is integrally formed with the thick portion 2. When the thick part 2 and the protrusion 4 are integrated in this way, the overall shape becomes complicated, which causes a problem of increased costs in the manufacturing process.

It is also conceivable to increase the thickness of the thick portion 2 by the length of the supply/discharge port 5 without forming the above-mentioned protrusion 4, thereby simplifying the shape of the bottom portion.

However, the greater the thickness of the thick wall portion 2, the longer the overall length of the first cylinder _S1 becomes. However, in this type of cylinder, the installation space is usually limited. If the thickness of the thick wall portion 2 is increased under conditions where the installation space is limited, a problem arises in that the effective stroke of the cylinder must be shortened accordingly.

The purpose of this invention is to simplify the shape of the bottom block and reduce its thickness.

(Means for Solving Problems) In order to achieve the above object, this invention provides a bottom block in the bottom part of the cylinder body, and a down control valve is installed in a cylinder in which a down control valve is installed inside the bottom block. While inserting the valve case into the bottom block, the cylindrical part of the port body is fitted to the outer periphery of the valve case, and the valve case is inserted between the bottom block and the large diameter part provided on the outside of the valve case. It is configured to sandwich the cylindrical portion of the port body.

(Operation of the present invention) Since the structure is constructed as described above, the bottom block only needs to have a thickness sufficient to insert the valve case of the down control valve. And between this valve block and the large diameter part of the valve case,
Since the cylindrical portion of the port body is sandwiched, the port portion of the port body can be freely positioned in the direction along the cylinder.

(Effects of the present invention) With the above structure, the bottom block only needs to have a thickness sufficient to insert the valve case, and since the bottom block and the port body are configured separately, the bottom block The shape of the block can be simplified.

Furthermore, by rotating the port body around its cylindrical portion, the supply/discharge port can be set at any position. In other words, if the port body is located parallel to the cylinder body, the overall length of the cylinder does not need to be increased.

(Embodiment of the present invention) A bottom block 19 is provided at the bottom portion of the first cylinder _S1 of this embodiment shown in FIG. The end of a valve case 20 of a down control valve V, which is functionally similar to the conventional one, is screwed into the bottom block 19.

The cylindrical portion 22 of the port body 21 is fitted into the valve case 20, and between the bottom block 19 and the large diameter portion 23 of the valve case 20,
The cylindrical portion 22 is held between them.

The port body 21 held in the above manner is
The supply/discharge port 24 is aligned with an annular groove 25 of the valve case 20.

Note that the configuration other than the above is the same as that of the prior art, so a detailed explanation thereof will be omitted.

Since the configuration is as above, bottom block 1
9 only needs to be thick enough to insert the valve case 20, and since the bottom block 19 and the port body 21 are constructed separately, the shape of the bottom block 19 can be simplified.

Moreover, by rotating the port body 21 around its cylindrical portion 22, the supply/discharge port 24 can be set at any position. In other words, if the port body 21 is positioned parallel to the cylinder body 26 as shown in the figure, the overall length of the cylinder does not need to be increased.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional view showing an embodiment of this invention, and FIG. 2 is a cross-sectional view of main parts showing a conventional example. 19...Bottom block, V...Down control valve, 20...Valve case, 21...Port body, 22...Cylinder part, 23...Large diameter part, 26...Cylinder body.

Claims (1)

[Scope of utility model registration request] In a cylinder in which a bottom block is provided at the bottom part of the cylinder body and a down control valve is installed inside this bottom block, the valve case of the down control valve is inserted into the bottom block, and the intake and exhaust ports are provided on the outer periphery of this valve case. A down control valve is provided in which a cylindrical portion of the port body having a cylindrical shape is fitted into the cylindrical portion of the port body, and the cylindrical portion of the port body is sandwiched between the bottom block and a large diameter portion provided on the outside of the valve case. cylinder.