JPH06213213A - Liquid pressure cylinder device - Google Patents

Abstract

PURPOSE:To provide a liquid pressure cylinder device having a high work efficiency by remarkably increasing return speed and stiffness thereof and decreasing its fluid resistance. CONSTITUTION:A rod-like center block 3 concentric with a liquid pressure cylinder 1 is provided on the cap side plate 2 of the liquid pressure cylinder 1, and a ring-like piston 5 is provided between this liquid pressure cylinder 1 and the center block 3. A hollow cylindrical piston rod 7 connected to this ring-like piston 5 is so provided as to surround the center block 3, and liquid supplying/discharging ports 8, 9 to/from a liquid chamber A located between the cap side plate 2 and the piston 5 and a liquid chamber B inside the piton rod 7 are provided, respectively. The liquid chamber B inside the piston rod 7 and a liquid chamber C between this piston rod 7 and the liquid pressure cylinder 1 are communicated with each other by an opening 10, and pressure receiving areas S1, S2 of these liquid chambers B, C are made different from each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid to which a high-speed returning mechanism is added for the purpose of shortening the time from when the ram descends to finish the machining until when the ram finishes ascending to improve productivity. The present invention relates to a hydraulic cylinder device suitable for a pressure press machine.

[0002]

2. Description of the Related Art In the conventional hydraulic cylinder device of a press machine, the speed of the process of returning to the original position for the next processing after the completion of processing is required to minimize the difference between the piston diameter and the rod diameter. This has been done by reducing the amount of the liquid required for the returning step. That is, since the amount of liquid required for the returning step is proportional to the pressure receiving area of the liquid chamber, the amount of liquid required is reduced when the rod diameter is as close to the piston diameter as possible. As a method other than increasing the rod diameter, a cylinder with a small piston pressure receiving area may be used in combination for high-speed return. However, this makes the mutual action points slightly different during high-speed movement. It is currently not used in high speed presses because it is difficult to keep the balance between the cylinders constantly.

FIG. 3 shows an example of a high-speed return device in a conventional hydraulic cylinder device. In the figure, 20 is a hollow cylindrical hydraulic cylinder, 21 is a cap side plate, and 22 is a cylinder mounting side plate. , 23 is a piston, 24 is a piston rod, 25 is a metal for piston rod, 26 is a tie rod, 27 is a tie rod nut, 28 is a cap side port, 29 is a head side port, 30 is a piston ring, 31 is a rod The oil seals 32 are O-rings, respectively.

In order to perform the press working with the above-mentioned apparatus, the liquid is introduced into the liquid chamber E from the cap side port 28 and the piston 23 is pushed down. Further, in order to return the piston 23 from that state, pressurized liquid is supplied to the liquid chamber F from the head side port 29 and the piston 23 is pushed up. This is the return step, and at this time, if the diameter d of the piston rod 24 is as close as possible to the diameter D of the piston 23, the required oil flow rate will decrease, but normally this method causes about 10% of the pressure receiving area of the liquid chamber E. Since the pressure receiving area of the liquid chamber F can be made small, a high-speed return of about 10 times the machining feed can be achieved.

[0005]

However, in the above-mentioned conventional apparatus, when the high-speed return of 10 times or more of the machining feed is attempted, there are the following problems. That is, in the device of FIG. 3, the piston ring 30 and the oil seal 31 are required to use commercially available products in terms of performance, but the size of these commercially available products is limited, so the diameter d of the piston rod 24 can be set freely. It cannot be set. Also, at the bottom dead center, the piston 23 hits the plate 22 and the shoulder portion 2
2a cannot be made too small from the viewpoint of strength, and the gap between the piston rod 24 and the cylinder 20 cannot be made too small because it is a fluid passage.

That is, in the conventional method, regardless of the required force, only the high-speed return speed of about 10 times the machining feed can be set due to the constraint of the cylinder, but the force required for the normal return process is the main pressing force. It is about 1%, and as a hydraulic pressure source, it has the ability to perform high-speed return of about 100 times the machining feed, so setting the high-speed return speed depends on how much force is required for returning. There is a demand for a mechanism with a high degree of freedom, which is limited only by this.

[0007]

SUMMARY OF THE INVENTION The present invention has been made from the above-mentioned viewpoint, in which a cap side plate of a hydraulic cylinder is provided with a round bar-shaped center block concentric with the hydraulic cylinder. A ring-shaped piston is provided between the center blocks, and a hollow cylindrical piston rod coupled to the ring-shaped piston is provided so as to enclose the center block, and a liquid chamber between the cap side plate and the piston is provided. And a liquid supply / discharge port for the liquid chamber in the piston rod, respectively, for communicating between the liquid chamber in the piston rod and the liquid chamber between the piston rod and the hydraulic cylinder, and A hydraulic cylinder device is configured by providing a difference in the pressure receiving area of the liquid chamber.

[0008]

As described above, the device of the present invention provides a slight difference between the pressure receiving area in the piston rod enclosing the center block and the pressure receiving area of the liquid chamber between the piston rod and the cylinder of the ring-shaped piston. It is possible to obtain a high return speed that is 100 times as high as the machining feed speed that cannot be achieved by the conventional method.

Further, in the present invention, since the ring-shaped piston is used, the bending rigidity of the piston itself is improved, and this piston is also supported by the center block of the round bar concentric with the cylinder, so that the rigidity is high. It is structured. Further, in the device of the present invention, since the liquid supply / discharge ports can be provided on the cap side plate, respectively, the switching valve can be directly mounted on the cap side plate. As a result, the piping is shortened and the workability at the time of assembling the machine is improved, and the flow resistance of the working fluid is also reduced, so that the switching time can be shortened.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In the figure, 1 is a hydraulic cylinder, and 2 is its cap side plate. In this embodiment, a round rod-shaped center block 3 which is concentric with the hydraulic cylinder 1 is fixed to the cap side plate 2 of the hydraulic cylinder 1 by a hollow bolt 4 and is provided between the hydraulic cylinder 1 and the center block 3. A ring-shaped piston 5 is provided in the center block 3, and a hollow cylindrical piston rod 7 connected to the ring-shaped piston 5 with a bolt 6 is provided so as to enclose the center block 3.

A liquid supply / discharge port 8 for the liquid chamber A between the cap side plate 2 and the piston 5 is provided in the cap side plate 2, and a liquid supply / discharge for the liquid chamber B in the piston rod 7 is provided. Mouth 9 is cap side plate 2
It is provided on the hollow bolt 4 screwed to the piston rod 7
The liquid chamber B in the inside and the liquid chamber C between the piston rod 7 and the hydraulic cylinder 1 are made to communicate with each other through an opening 10 provided in the body portion of the piston rod 7, and the pressure receiving area of the liquid chamber B is S ₁ is made slightly smaller than the pressure receiving area S ₂ of the liquid chamber C.

Reference numeral 11 is a mounting side plate of the hydraulic cylinder 1, 12 is a piston rod metal, 13 is a tie rod for fastening the cap side plate 2 and the mounting side plate 11, 14 is a tie rod nut, 15
Is a piston ring, 16 is an oil seal, and 17 is an O-ring.

In the apparatus of the present invention configured as described above, the liquid introduced from the supply / discharge port 9 on the head side passes through the hollow bolt 4 to which the center block 3 is attached and the liquid chamber B.
At the same time, the liquid is introduced into the liquid chamber C through the opening 10 opened in the piston rod 7. Pressure receiving area S ₂ of liquid chamber C
If the hydraulic pressure from the hydraulic pressure source acts on the pressure receiving area obtained by subtracting the pressure receiving area S ₁ of the liquid chamber B from, the returning step is performed. In other words, most of the liquid required for the liquid chamber C is supplied from the liquid chamber B, so that a high-speed return is possible by supplying a sufficient amount of liquid from the hydraulic pressure source to generate the necessary pressing force. It is a translation. Further, in order to achieve high-speed return, it is necessary to have a structure having a small flow resistance, but according to the present invention, the liquid supply / discharge ports 8 and 9 may be arranged in parallel on the cap side plate 2. Therefore, the switching valve (not shown) can be directly mounted on the plate 2, and the flow resistance can be made smaller than that of the conventional method by shortening the piping.

[0014]

As described above, the device of the present invention has the pressure receiving area S ₁ of the liquid chamber B in the piston rod 7 which encloses the center block 3 and the liquid between the piston rod 7 and the cylinder 1 of the ring-shaped piston 5. By providing a slight difference (S ₂ −S ₁ ) in the pressure receiving area S ₂ of the chamber C, it is possible to obtain a high return speed as high as 100 times the machining feed multiple, which cannot be achieved by the conventional method. Therefore, it is possible to obtain an effect that the efficiency of press work can be remarkably improved.

Further, in the present invention, since the ring-shaped piston is used, the bending rigidity of the single piston is improved, and the piston 5 is also supported by the center block 3 of the round bar concentric with the cylinder 1. It has a highly rigid structure. Further, in the device of the present invention, liquid supply / discharge ports 8, 9
Can be mounted on the cap side plate 2, so that the switching valve can be directly mounted on the cap side plate 2 and the piping can be shortened, so that workability at the time of machine assembly is improved. Further, the flow resistance of the hydraulic fluid is reduced, and the switching time of the switching valve is shortened.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a device of the present invention.

2 (a) is a perspective view showing the piston of FIG. 1 and a mounting bolt thereof, and FIG. 2 (b) is a perspective view of the piston rod of FIG.

FIG. 3 is a vertical cross-sectional view of a conventional device.

[Explanation of symbols]

1 Hydraulic cylinder 2 Cap side plate 3 Center block 4 Hollow bolt 5 Piston 6 Bolt 7 Piston rod 8 and 9 Liquid supply / discharge port 10 Opening A, B, C, E, F Liquid chamber S ₁ Liquid chamber B pressure receiving area S ₂ Pressure receiving area of liquid chamber C 11 Mounting side plate 12 Piston rod metal 13 Tie rod 14 Tie rod nut 15 Piston ring 16 Oil seal 17 O-ring 20 Hydraulic cylinder 21 Cap side plate 22 Mounting side plate 23 Piston 24 Piston rod 25 Metal for piston rod 26 Tie rod 27 Nut for tie rod 28,29 Port 30 Piston ring 31 Oil seal for rod 32 O-ring

Claims (1)

[Claims] 1. A cap side plate of a hydraulic cylinder is provided with a round bar-shaped center block concentric with the hydraulic cylinder, a ring-shaped piston is provided between the hydraulic cylinder and the center block, and the ring-shaped piston is provided. A hollow cylindrical piston rod coupled with the center block is provided so as to enclose the center block, and a liquid chamber between the cap side plate and the piston and a liquid supply / discharge port for the liquid chamber in the piston rod are respectively provided. A fluid pressure inside the piston rod and a fluid chamber between the piston rod and the fluid pressure cylinder are communicated with each other, and a pressure receiving area between these fluid chambers is different from each other. Cylinder device.