JPH06190592A - Hydraulic press equipment - Google Patents

Abstract

PURPOSE:To provide a hydraulic press equipment provided with a fast forward mechanism whose productivity and workability are satisfactory. CONSTITUTION:To a hydraulic cylinder 1 having a press ram 2, a hydraulic circuit is connected through a solenoid valve having a ram extrusion valve part 13a, a ram stop valve part 13b and a ram return valve part 13c. To a piping 14 allowed to branch from a circuit for a pressure liquid into a cap side liquid chamber 1b of the hydraulic cylinder 1 through this ram extrusion valve part 13a, a sub-tank 15 is connected, and also, in the piping 14 connected to this sub-tank 15, a check valve 16 for allowing a flow from the sub-tank 5 is provided.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention shortens the time from the start of operation to the approach of the mold to the material in the pressing process,
The present invention relates to a hydraulic press machine with a rapid feed mechanism added to improve productivity.

[0002]

2. Description of the Related Art In the case where the shape after processing such as drawing is three-dimensional, the mold is greatly opened to take out the product, so that the distance from the start of operation to the contact between the material and the mold becomes long. However, since the feed is not processed during this period,
Since the cycle time becomes long if the feeding is performed under the same conditions as the machining feeding, a fast-forward mechanism that decelerates to the machining feeding speed during the feeding only at the beginning is required. For this reason, various rapid traverse mechanisms have been devised in the past, but in these conventional methods, in order to switch from rapid traverse to machining traverse, a dedicated solenoid valve for fast traverse and dedicated machining traverse is provided, and proximity switches etc. are used. It has been common to detect that the set position has been reached and switch the solenoid valve electrically.

4 to 7 show an example of a conventional hydraulic press device. In the drawings, 1 is a hydraulic cylinder used for pressing, 2 is a press ram connected to its piston 1a, 1b is a cap side liquid chamber of the cylinder 1, 1c
Is a liquid chamber on the head side of the cylinder 1. In addition, 3 is a hydraulic pump, 4 is a main tank, 5 is a solenoid valve for machining feed,
5a and 5b are solenoids. Further, 6 is a solenoid valve for fast-forwarding, 6a is a solenoid, and 6b is a return spring. And each said apparatus is connected by piping 7,8,9,10,11,12.

FIG. 4 shows a state in which the press machine is stopped. From this state, when the solenoid 6a for fast-forwarding is switched to the state of FIG. 5, the pressure discharged from the hydraulic pump 3 is changed. The liquid enters the liquid chamber 1b on the cap side through the pipes 7, 8, and 9 as indicated by arrows A, B, and C, and at the middle of the pipe 9, through the pipes 10 and 11, the arrows D and E.
As shown in Fig. 2, a part of the pressure liquid tries to enter the head side liquid chamber 1c of the cylinder 1, that is, the liquid pressure acts on both the upper and lower surfaces of the piston 1a. Since the area is wider than the pressure receiving area on the head side, the ram 2 is pushed down by the difference.

When the piston 1a descends, the liquid in the liquid chamber 1c on the head side of the cylinder 1 is pushed out, and the piping
As shown by arrows F, G, and C via 11 and 10, the liquid enters into the liquid chamber 1b on the cap side. Therefore, in this case, the ram 2 is fast-forwarded because the amount of liquid flowing into the liquid chamber 1b is large.

Next, for the machining feed, the solenoid valve 6 for fast feed is switched as shown in FIG. 6 and the solenoid valve 5 for machining feed is switched. By doing so, the liquid discharged from the hydraulic pump 3 enters the liquid chamber 1b on the cap side through the pipes 7, 10, 9 as shown by arrows H and I, and the liquid in the liquid chamber 1c on the head side is removed. It flows through the pipes 11 and 12 as shown by the arrow J and returns to the inside of the main tank 4. In this case, since the liquid in the liquid chamber 1c on the head side does not return to the liquid chamber 1b on the cap side, the machining feed is slower than the fast feed described above.

To return the ram 2 that has been pushed down, the machining feed solenoid valve 5 is switched as shown in FIG. With this configuration, the discharge liquid of the hydraulic pump 3 flows through the pipes 7 and 11 in the direction of the arrow K to enter the liquid chamber 1c on the head side,
The liquid in the liquid chamber 1b on the cap side passes through the pipes 9, 10, and 12 by the arrow L.
And flows back into the main tank 4. Therefore, in this case, the ram 2 rises and returns to its original position.

[0008]

As described above, in the conventional apparatus, the machining feed solenoid valve 5 and the fast feed solenoid valve 6 are used.
And two solenoid valves are required, and the position from the rapid feed to the machining feed must be appropriately specified by changing the position of the proximity switch each time the mold is replaced. In order to switch the feed rate, the operator sets the feed rate switching position by considering the temperature of the mold, working fluid, material variations, etc. However, there is a problem that this work takes a lot of time.

The fast-forwarding mechanism is adopted to increase the production quantity of press working, but the conventional solenoid valve is used.
The method of individually using a proximity switch or the like and causing a delay by the time required for switching the solenoid valve is not suitable for a press machine that operates at high speed and a short stroke.

[0010]

In order to solve the above problems, in the present invention, a hydraulic cylinder having a pressing ram, a ram pushing valve portion, a ram stopping valve portion,
A hydraulic circuit is connected via an electromagnetic valve having a ram return valve section, and a sub tank is connected to the circuit for sending the pressure liquid to the cap side liquid chamber of the hydraulic cylinder via the ram pushing valve section, A check valve that allows the flow from the sub-tank is provided in the connection circuit to the sub-tank to configure the hydraulic press device.

[0011]

As described above, in the present invention, only one solenoid valve is used, and switching from high speed to low speed is automatically performed at the position where the mold comes into contact with the material, so that the device is simplified. At the same time, the cycle time is shortened, and complicated setting of the proximity switch and the like and adjustment work are not required, which facilitates the handling.

Further, in the conventional system, the pressure relief circuit is indispensable, which causes the cycle time to be extended.
In processing such as drawing or cold forging that requires a pressing force to the end, it is necessary to depressurize the cap side of the cylinder in the conventional device, but according to the device of the present invention, in the punching process, punching is performed. The rear ram begins to fall under its own weight and the cap side of the cylinder is released to the sub tank, eliminating the need for pressure relief. This has a great effect on shortening the cycle time of punching.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the device of the present invention will be described below with reference to FIGS. In the figure, the same reference numerals as those used in the previous description denote the same items. That is, in the figure, 1 is a hydraulic cylinder used for pressing, 2 is a press ram connected to its piston 1a, 1b is a cap side liquid chamber of the cylinder 1,
c is a liquid chamber on the head side of the cylinder 1. Further, 3 is a hydraulic pump, and 4 is a main tank.

In this embodiment, the valve portion for pushing out the ram
13a, a ram stop valve portion 13b, and a ram return valve portion 13c, and a hydraulic cylinder 1 having a pressing ram 2 through a solenoid valve 13 having solenoids 13d and 13e on both sides thereof. To be able to supply. That is, 7 is a pipe for connecting the discharge port of the hydraulic pump 3 and the solenoid valve 13,
Reference numerals 0 and 9 are pipes connecting the solenoid valve 13 and the liquid chamber 1b on the cap side of the hydraulic cylinder 1, 11 is a pipe connecting the liquid chamber 1c on the head side of the hydraulic cylinder 1 and the solenoid valve 13, and 12 is This is piping for the drain of the solenoid valve 13.

A sub-tank 15 is connected to a pipe 14 branched from the middle of the circuits 10 and 9 for feeding the pressure liquid to the cap side liquid chamber 1b of the hydraulic cylinder 1 through the ram pushing valve portion 13a. A check valve that allows the flow from the sub tank 15 in the pipe 14 connected to this sub tank 15.
16 is provided. Reference numeral 17 is a pipe for overflowing the sub tank 15 that connects the sub tank 15 and the pipe 12.

FIG. 1 shows the stopped state of the pressing apparatus of the present invention. When the solenoid valve 13 is switched from this state by the solenoid 13d as shown in FIG. 2, the pressure liquid discharged from the hydraulic pump 3 is piped. It flows in the direction of arrow M through 7, 10 and 9 and enters into the cap side liquid chamber 1b of the hydraulic cylinder 1, and is lowered by the weight of the ram 2 due to its own weight.
The liquid in 15 flows into the liquid chamber 1b through the pipe 14, the check valve 16 and the pipe 9. As the ram 2 descends, the liquid in the liquid chamber 1c flows through the pipes 11 and 12 in the direction of the arrow N and flows into the main tank 4
Return to. That is, in this case, the descent of the ram 2 is fast-forwarded by the amount of the liquid flowing through the check valve 16.

The ram 2 descends and the die and material (not shown)
The point where the ram 2 comes in contact with the ram 2 ends due to its own weight.
That is, if the die attached to the ram 2 comes into contact with the material and the ram 2 tries to stop once, the hydraulic pressure in the liquid chamber 1b rises, and the hydraulic pressure is also applied to the check valve 16 in the direction of arrow O. Therefore, the check valve 16 is closed and the outflow of the liquid from the sub tank 15 is stopped. For this reason, the ram 2 has a machining feed speed which is reduced by the discharge liquid from the hydraulic pump 3 from the previous rapid feed.

FIG. 3 shows the returning process of the ram 2. In this case, the solenoid valve 13 is switched by the solenoid 13e so that the ram return valve portion 13c is connected to the circuit. In this case, the liquid discharged from the hydraulic pump 3 flows through the pipes 7 and 11 in the direction of the arrow P and enters the liquid chamber 1c of the cylinder 1 to raise the ram 2. As the ram 2 rises, the liquid in the liquid chamber 1b passes through the check valve 16 and the pipe 14 opened by the pilot pressure from the solenoid 13e through the pipe 18 shown by the broken line in FIG. . This allows
The sub-tank that has recovered the amount of liquid lost in the high speed feeding process can supply the necessary liquid in the next high speed feeding process.

[0019]

As described above, in the present invention, only one solenoid valve 13 is used, and switching from high speed to low speed is automatically performed at the position where the die contacts the material.
In addition to simplifying the apparatus, the cycle time is shortened, and since complicated setting changes such as proximity switches and adjustment work are unnecessary, there is an effect that handling is easy.

In the conventional method, a pressure release circuit on the cap side of the cylinder is indispensable after punching in processing requiring pressing force to the end such as drawing and cold forging, which is a cause of extending the cycle time. Was there. According to the device of the present invention, in punching or the like, after punching, the ram further falls by its own weight, and at that time, the pressure of the liquid chamber 1b on the cap side of the cylinder 1 is released to the sub tank 15 via the check valve 16. Therefore, there is no need to perform depressurization. This has a great effect on shortening the cycle time of punching.

[Brief description of drawings]

FIG. 1 is a diagram showing a stopped state of a hydraulic circuit of a device of the present invention.

FIG. 2 is a hydraulic circuit diagram when the ram of the device of the present invention is lowered.

FIG. 3 is a hydraulic circuit diagram when the ram of the device of the present invention is raised.

FIG. 4 is a diagram illustrating a stopped state of a hydraulic circuit of a conventional device.

FIG. 5 is a hydraulic circuit diagram when the ram of the conventional device is fast-forwarded.

FIG. 6 is a hydraulic circuit diagram when a ram of a conventional device is machine-fed.

FIG. 7 is a hydraulic circuit diagram when the ram of the conventional device rises.

[Explanation of symbols]

 1 Hydraulic cylinder 1a Piston 1b Cap side liquid chamber 1c Head side liquid chamber 2 Ram 3 Hydraulic pump 4 Main tank 5 Solenoid valve for machining feed 6 Solenoid valve for fast feed 7-12 Piping 13 Solenoid valve 13a Ram pushing valve 13b Ram stop valve 13c Ram return valve 13d, 13e Solenoid 14 Piping 15 Sub tank 16 Check valve 17, 18 Piping

Claims (1)

[Claims] 1. A hydraulic circuit having a press ram connected to a hydraulic circuit via a solenoid valve having a ram pushing valve part, a ram stopping valve part and a ram returning valve part. A sub-tank was connected to the circuit that sends the pressure liquid to the cap-side liquid chamber of the hydraulic cylinder via the push-out valve section, and a check valve that allows the flow from the sub-tank was provided in the connection circuit to this sub-tank. A hydraulic press device characterized in that