JPS5815683Y2 - Single-acting hydraulic cylinder with quick return mechanism - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a single-acting hydraulic cylinder and cylinder having a quick return mechanism.

More specifically, a gas bag is housed in the middle of the cylinder, and the piston is quickly returned to the starting position by the compression and expansion action of the gas bag.

Known single-acting cylinders include those shown in FIGS. 1 and 2.

In the case of FIG. 1, it operates only for one stroke.

In this case, when the operation is finished and the fluid is discharged from the cylinder, some external force will move the piston to the starting position.
I have to bring it back.

Such single-acting cylinders were used in applications where return by gravity was possible, such as vertical movement.

The case shown in FIG. 2 is a spring return type hydraulic cylinder, and a spring for returning the piston is provided inside the cylinder.

Since this cylinder requires a space to house the spring, it requires a space that is more than twice the required stroke length, and has the disadvantage that the overall length of the cylinder becomes significantly longer.

The present invention improves the drawbacks of the known cylinders mentioned above, and aims to provide a hydraulic cylinder in which the piston can be returned quickly and the overall length of the cylinder can be made very short.

The structure of the invention that meets the above-mentioned problems is as follows.

A middle cylinder with a smaller diameter than the outer cylinder is provided integrally with the piston above the piston that reciprocates inside an outer cylinder equipped with a sealed lid, and the upper part of this middle cylinder is sealed with a stopper, and an open hole connects the outer cylinder and the middle cylinder. It communicates with the room between.

A compressible and expandable gas bag is enclosed within this middle cylinder.

On the other hand, the piston is provided with a through hole connecting the chamber in the middle cylinder and a chamber in the lower part of the piston, and a horizontal hole and a small diameter hole concentric therewith, perpendicular to the through hole.

An auxiliary piston is fitted into this horizontal hole, and a piston rod of the auxiliary piston reciprocates within the small diameter hole.

It looks like this. The auxiliary piston is biased by a spring and normally closes the through hole without aligning the small diameter portion of the piston rod with the through hole.

In addition, the chamber on the opposite side of the auxiliary piston from the spring has a through hole and communicates with the lower chamber of the piston, so that the piston can be quickly returned to the starting position by the compression and expansion of the gas bag.

Next, an embodiment of this invention will be described below based on FIGS. 3 and 4.

3 and 4, 2 is a piston.

A through hole 13 is provided in the center of the piston 2 to communicate the piston lower chamber A and the chamber C in the middle cylinder 3.

Further, the chamber C inside the middle cylinder communicates with the chamber B outside the middle cylinder through an opening 11.

Chambers C and B are filled with oil.

Reference numeral 14 denotes an auxiliary piston, which is fitted into a horizontal hole 15 provided in the piston 2.

One side of the auxiliary piston 14 is biased toward the right side in the figure by a coil spring 16.

17 is a piston rod of the auxiliary piston 14, which is connected to the through hole 13.
It is slidably fitted into a small diameter hole 18 that intersects with.

19 is a through hole connecting the horizontal hole 15 and the piston lower chamber A.

20 is a small diameter portion of the piston rod 17, and the auxiliary piston 1
4 is configured to align with the through hole 13 when it moves to the left against the coil spring 16.

5 is a plug of the middle cylinder 3, 7 is a seal, and 8 is an O-ring.

4 is a compressible/expandable gas bag sealed in the middle cylinder.

Due to the above structure, the piston 2 is in the state shown in FIG. 3 when no pressure oil is supplied.

However, the chamber C inside the middle cylinder 3 and the chamber B between the middle cylinder 3 and the outer cylinder 1
Oil is always shining inside, and the inlet pipe 10 at the bottom of the outer cylinder
When pressure oil is supplied to the lower chamber A of the piston 2, pressure acts on the lower surface of the piston 2.

At the same time, pressure is applied to the right side of the auxiliary piston 14 through the through hole 19.

Then, the auxiliary piston 14 moves to the left against the coil spring 16, and as a result, the small diameter portion 20 of the piston rod 1γ and the through hole 13 come into alignment.

Then, since chambers C and B communicate through the through hole 11, the same pressure as in chamber A acts in chambers C1 and B, but due to the difference in area between the top and bottom surfaces of piston 2, piston 2 moves upward. Pushed - bearded.

The piston 2 continues to rise, and as shown in Fig. 4, the stopper 12 rises at the casing that touches the inner surface of the sealing lid 6 of the outer cylinder 1, and the gas bag 4 is compressed (Fig. 4).

When the pressure in chamber A is released in this state, the auxiliary piston 14
Since the pressure applied to the right side of the piston 14 is also released, the piston 14 is pushed to the right side by the coil spring 16 and instantly closes the passage hole 13.

Then, the pressure in chambers B and C becomes smaller than the pressure in chamber A, so the piston 2 is pushed downward and begins to return.

Furthermore, the gas in the air bag 4 in the middle cylinder 3 also begins to expand, transmitting its pressure to the oil in chambers B and C, and the return of the piston 2 is further promoted.

As described above, according to the present invention, the piston is raised and lowered by the total pressure difference between the upper and lower parts of the piston through the upper and lower chambers of the piston by the auxiliary piston inside the piston without responding to the pressure applied to the lower part of the piston, so that stable movement can be achieved. be able to.

In addition, a gas bag that can be expanded and expanded is inserted into the middle cylinder, and when the pressure is applied, the bag is deflated, and when the hydraulic pressure is released, the expansion pressure of the gas bag causes the gas bag to return quickly. In comparison, the overall length of the cylinder and cylinder can be made very short, and the operation is of course very smooth.

[Brief explanation of the drawing]

Fig. 1 shows a known single-acting oil cylinder Fig. 2 shows a known spring return type oil cylinder Fig. 3 shows a hydraulic cylinder according to the present invention Fig. 4 shows the state in which the piston in Fig. 3 is raised . As shown in the figure, 1...outer cylinder, 2...piston, 3...
・Middle tube, 4... Gas bag, 5... Plug at the top of the middle tube, 6.
... Airtight lid of outer cylinder, γ ... Seal, 8 ... 0 ring, 10 ... Inlet pipe, 11 ... Opening, 12 ... Stopper at the bottom of middle cylinder, 13 ... Opening Hole, 14... Auxiliary cylinder, Under, 15... Horizontal hole, 16... Coil link, 17... Piston rod, 18... Small diameter hole, 19... Through hole, 20... ...Small diameter section.

Claims (1)

[Scope of utility model registration request] An outer cylinder 1 equipped with a sealing lid 6, a piston 2 fitted into the outer cylinder, and an outer cylinder having a smaller diameter than the outer cylinder and provided above the piston in one body and sealed with a stopper 5 and with an opening 11. The piston 2 has a chamber C in the middle tube 3 and a chamber A in the lower part of the piston. an auxiliary piston 14 that slides orthogonally to the through hole and has a piston rod 1γ having a small diameter portion 20, and the auxiliary piston 14 is always biased to close the through hole 13. A single-acting hydraulic cylinder with a quick return mechanism characterized by a spring 16 and a through hole 19 connecting the chamber on the opposite side of the spring to the chamber A at the bottom of the piston.