JPS5951397B2 - Hydraulic punch for press - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to metal machining, and more particularly to hydraulic presses.

The invention can be advantageously used for the production of fast-acting hydraulic presses for drilling plate-like materials with working media such as elastic media, liquid-elastic media (liquid with an intervening elastic diaphragm) and fluid media. .

In addition, the invention can be applied to the manufacture of pneumatic impact presses.

Some known hydraulic punches include a cylinder and a ram movably disposed within the cylinder.

The ram is urged downward by compressed gas, striking the elastic medium within the working chamber.

As a result, high pressures are created in the elastic medium, resulting in deformation of the workpiece.

In front of the elastic medium, in order to prevent the pressure in the cylinder from increasing excessively in the gap between the ram and the elastic medium (fluid) and to prevent the kinetic energy of the ram from being dissipated by the air cushion. A portion of the arranged cylinder chamber communicates with the atmosphere via an outlet duct.

However, the above construction has problems in returning the ram to its original position at the completion of the working stroke.

Known hydraulic pumps, for example, are those in which a ram is raised to its original position by means of a working fluid flowing into the underside of the ram from a hydraulic drive.

Once the ram is raised, fluid must be removed from the cylinder.

For example, fluid withdrawal can be accomplished by blowing air into the cylinder.

To this end, the hydraulic system must be equipped with various control, adjustment, and switching devices, pumps, piping, and other auxiliary elements, resulting in a complex structure.

The time required for raising the ram, blowing air, and draining fluid can be as long as 50 to 60 seconds (eg, US Pat. No. 1,562,426).

For other hydraulic punches (e.g. ExpressInfo
rmation Bulletin 1971 No. 2
No. 1 Forging and Pressing P
production technology
In the uipment series, High-3p
eed Working by Hydropunch
R, Ratjen, M, entitled Method.
Takamatsu), when the ram shocks the fluid, the ram upper chamber of the cylinder is sequentially communicated through the respective valves with the compressed gas chamber, then with the atmosphere, and finally with the negative pressure chamber.

The disadvantage is therefore that the duration of one working cycle for returning the ram to its original position is long.

Furthermore, the provision of valves, piping, and containers complicates the construction of the hydraulic punch and increases cost.

Yet another hydraulic shock loading device is disclosed in French Patent No. 21.
No. 38378 is known.

It has a cylinder with a stepped ram and a chamber containing a water diaphragm, which chamber is located in front of the cylinder and separated from it by a partition forming an opening in the center to receive the ram. ing.

The partition has a plurality of holes facing the recess in the ram through which air flows to effect the return stroke of the ram;
a headpiece providing the water supply necessary to form the diaphragm, a water outlet and an air vent, an air supply control valve, an additional air distribution line, a gate, a return stroke distribution line;
It includes a valve and passageway and piping system to stop the ram during the return stroke.

In this above-mentioned device, the means for returning the ram to its original position are a return stroke control valve, a duct (passage) that communicates the direction control valve with the cylinder, and a valve for a passage that supplies air to the lower side of the ram through the control valve. and a duct that communicates the upper ram chamber with the atmosphere through a control valve.

The ram returns to its original position as follows.

When the downwardly moving ram reaches the water diaphragm, the ram accelerating air passes through the duct and displaces the return stroke control valve plunger, placing the upper ram chamber in communication with the atmosphere.

As a result, air pressure is introduced offshore of the cylinder.

At the same time, air from the container is introduced to the underside of the ram and a return stroke is performed.

As the pressure drops within the cylinder, the spring actuated plunger of the control valve returns to its original position, thus isolating the upper ram chamber and cutting off the air supply to the underside of the ram.

Once the desired speed is achieved, the ram continues to move under its moment of inertia, which at the end of the return stroke is damped by the air present in the upper ram chamber of the cylinder.

However, this device is not without its drawbacks, the most important of which is that it is complex in construction and can be unreliable in operation.

All compressed gas control valves of this type are subject to gas leakage through the gap between the housing and the valve assembly.

To prevent gas leakage within the air control valve, the gap between the housing and the valve assembly must be minimal (ideally a gapless assembly).

Due to the presence of moisture in the air, parts must be made of corrosion-resistant materials.

In addition, this type of control valve requires the use of air completely free of solid impurities.

It is also necessary to use a good mist of lubricating oil to lubricate surfaces where friction occurs.

Another drawback is the requirement to direct air under the ram at a high inlet velocity to perform the return stroke.

As the ram returns to its home position, the auxiliary control valve drawbar is struck, shortening its life.

Yet another drawback is that there is no means to hold the ram in its original position, resulting in malfunction of the ram.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to overcome the above-mentioned drawbacks and to provide a hydraulic punch for a press in which the mechanism for returning the ram to its original position has a simpler structure and more efficient operation.

This objective is achieved by a hydraulic punch for presses as follows.

That is, it comprises a cylinder whose one end faces the working surface of the die through a high-pressure chamber filled with a working medium, in which a ram is movably disposed, the upper side of the ram in the cylinder;
A ram upper chamber and a ram lower chamber are respectively formed on the lower side, a compressed gas chamber is arranged around the cylinder, and at the end remote from the working surface of the die, said cylinder and compressed gas chamber are closed by a cover, and the compressed gas chamber is closed with a cover. It is equipped with an actuator 4 for selectively communicating the gas chamber with the upper chamber of the ram and driving the ram toward the die, and a ram home position return means for returning the ram to its home position. a closed chamber that communicates with the lower chamber; a valve that selectively communicates the upper chamber of the ram with the atmosphere; a check valve provided to introduce the ram, the closed chamber being arranged flush with the cylinder at the end of the cylinder proximate to the die, and the wall of the cylinder communicating the lower chamber of the ram with the interior of the closed chamber. the actuator has a cam for closing or opening the valve;

The construction according to the invention eliminates valves and piping systems, making operation simple and reliable, and reducing energy losses due to compressed gas leakage through sliding valve gaps and gas leakage through piping. It can be prevented.

According to the present invention, the following hydraulic punch is also provided.

That is, it has a cylinder whose one end faces the working surface of the die through a high-pressure chamber filled with a fluid as a working medium, and a ram is movably provided within the cylinder, and the upper and lower sides of the ram within the cylinder are disposed in the cylinder. A ram upper chamber and a ram lower chamber are respectively formed on the sides, a compressed gas chamber is arranged around the cylinder, and at the end remote from the working surface of the die said cylinder and compressed gas chamber are closed off by a cover, in which the compressed gas The ram is provided with an actuator for selectively communicating the chamber with the ram upper chamber and driving the ram toward the die, and an original position return means for returning the ram to its original position, and the ram original position return means is connected to the ram lower chamber. a valve that selectively communicates the upper chamber of the ram with the atmosphere; and a valve that introduces gas into the closed chamber on the wall of the cylinder at a distance approximately equal to the thickness of the ram from the end of the cylinder facing the die. the closed chamber is arranged flush with the cylinder at the end of the cylinder proximate to the die, and the wall of the cylinder has a passage connecting the lower chamber of the ram with the interior of the closed chamber. and the actuator is provided with a cam for closing or opening the valve, and further includes a check valve in a high pressure chamber filled with fluid as a working medium, through which the compressed gas flows into the ram. It enters the chamber that is introduced below and is to be filled with fluid.

With this configuration, even when the amount of deformation of the workpiece is large, the ram can be reliably returned to its original position.

The invention will now be explained by way of examples with reference to the accompanying drawings.

The illustrated hydraulic punch is part of a hydraulic press.

The hydraulic punch has a cylinder 1, one end of which faces the die 2 of the hydraulic press.

The cylinder 1 contains a ram 3, and the ram 3 has an actuator 4 and a ram home position return means for returning the ram to its home position.

A lower ram chamber 5 and an upper ram chamber 6 are formed below and above the ram 3.

In the uppermost position, the ram 3 is held in the position formed by the collet 7, which also acts as a shock absorber, and the ram 3 returns to its raised home position upon completion of the working cycle.

A ram actuator 4 is provided facing the upper end of the cylinder 1 on the opposite side from the die 2.

The hydraulic punch furthermore has a compressed gas chamber 8 arranged adjacent to and surrounding the cylinder 1.

The compressed gas chamber 8 communicates with a compressed gas source (not shown) and with the ram upper chamber 6 of the cylinder 1 through a passage 9 .

A cover 10 is also provided which closes off both the cylinder 1 and the compressed gas chamber 8.

The end of the cylinder 1 facing the die 2 adjoins a high pressure chamber 11 which is filled with an elastic medium (fluid) 12 which transfers energy from the ram 3 to the die 2. It functions as a working body that transmits to the workpiece 13 above.

According to the invention, the ram restoring means for returning the ram 3 to its original position have a closed chamber 14 arranged coextensive with the cylinder 1 at the end facing the die 2 .

The interior 15 of the closed chamber 14 is in communication with the lower ram chamber 5 of the cylinder via a passage 16.

The home position return means further includes a valve 17 that allows the ram upper chamber 6 of the cylinder to communicate with the atmosphere.

This valve 17 is provided in an opening formed in the cover 10,
It communicates with the ram upper chamber via a passage 18.

The valve 17 is opened by a cam 19 communicating with a cylinder rod (not shown) of the actuator 4.

The home position return means for returning the ram 3 to its home position is further provided within the wall of the cylinder 1 at a distance approximately equal to the axial length of the ram 3 from the end facing the die 2. A check valve 20 is provided.

The check valve 20 serves to introduce the gas used for pressurization into the interior 15 of the closed chamber 14 .

Instead of an elastic medium (rubber), a liquid elastic medium (which can be a liquid separated from the workpiece by an elastic diaphragm) or a die loaded with the workpiece is pressurized against the high-pressure chamber and then the high-pressure chamber is Filling fluids can be used.

When a fluid is used as the working body, a check valve 21 (FIG. 2) is provided in the body of the high pressure chamber 11.

This check valve 21 serves to guide the compressed gas from the compressed gas chamber 22 into the high pressure chamber 11 below the ram 3 and filled with fluid 22 .

Fluid is supplied to the high pressure chamber 11 via a nozzle 24 that is connected to the fluid supply system.

The nozzle 24 extends inside the closed chamber 14 and is provided with a check valve 25 .

The hydraulic punch according to the present invention operates as follows.

FIG. 1 shows the final state of the return of the ram 3 to its original position, with the passage 9 closed and the valve 17 opened.

Compressed gas from the interior 15 of the high pressure chamber 14 forces the ram 3 to move upwards.

At the end of its upward stroke, the ram 3 engages the collet 7, dissipates its kinetic energy and is retained therein.

In order to start the working stroke of the ram 3, the actuator 4 opens the passage 9 by means of a cylinder rod (not shown).

At the same time, the upwardly moving cam 19 moves away from the valve 17
is closed and the ram upper chamber 6 is isolated from the atmosphere.

By opening the passage 9, compressed gas from the compressed gas chamber 8 is introduced into the ram upper chamber 6, urging the ram 3 downward.

During the downward movement of the ram 3, the air in the ram lower chamber 5 is forced out and introduced into the interior 15 of the closed chamber 14 via the passage 16.

Upon reaching its lowest position, the ram 3 strikes the elastic medium 12, thereby converting the energy accumulated during the downward movement into impact pressure and causing a deformation of the workpiece on the die 2.

When the ram 3 reaches its lowest position, the compressed gas that caused the downward movement of the ram 3 is introduced into the interior 15 of the closed chamber 14 via the check valve 20.

With a portion of the compressed gas contained in the ram upper chamber 6, the actuator 4 closes the passage 9, and then, under the action of the cam 19, the valve 17 is opened and the ram upper chamber 6 communicates with the atmosphere by the passage 18.

The ram that applied deformation energy to the workpiece is placed in a closed chamber 14.
is raised by compressed gas from the interior 15 of the collet 7 until it engages with the collet 7.

The operating cycle is thus completed and the hydraulic punch is ready for the next cycle.

A hydraulic punch according to another embodiment of the invention, which performs a similar operation using liquid as an alternative working medium, operates as follows.

The workpiece 13 is fixed in position on the die 2 and both are brought into pressure contact with the high pressure chamber 11, after which the fluid 23 passing through the check valve 25 fills the high pressure chamber 11 through the nozzle 24. Supplied in sufficient quantity.

After gaining the starting moment, the ram strikes the fluid 23, deforming the workpiece and further lowering the ram to a depth below the height of the passage 16, determined by the amount of deformation of the workpiece. .

To raise the ram, compressed gas is supplied from inside the compressed gas chamber 22 via the valve 26 to the high pressure chamber 11 .

This high pressure chamber 11 is filled with an amount of fluid not exceeding the amount of gas required to raise the ram 3 to a height where the lower end of the ram 3 exceeds the lower edge of the passage 16 (the volume of the container is adjusted to this requirement). It is determined).

The upward movement of the ram 3 into its home position until it engages the collet 7 takes place under the action of compressed gas present in the interior 15 of the closed chamber 14, similar to that described for the embodiment of FIG. It is.

This construction of the hydraulic punch, in which fluid acts as a working medium, ensures a reliable return of the ram to its original position even in the case of large deformations.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a hydraulic punch for press according to the present invention, and FIG. 2 is a similar longitudinal sectional view of one having a check valve for introducing compressed gas into a high pressure chamber filled with working fluid. . 1...Cylinder, 2...Die, 3...
...Ram, 4...Actuator, 5...
... Ram lower chamber, 6... Ram upper chamber, 8.
...Compressed gas chamber, 10...Cover, 11
... Hyperbaric chamber, 14 ... Closed room, 15.
...Inside the closed room, 16...Passway, 17
...Valve, 20.21...Check valve.

Claims (1)

Claims: 1. A cylinder 1 with one end facing the working surface of a die 2 and a high-pressure chamber 11 filled with a working medium, in which a ram 3 is movably disposed; A ram upper chamber 6 and a ram lower chamber 5 are provided above and below the ram 3, respectively.
is formed, a compressed gas chamber 8 is arranged around the cylinder 1, at the end remote from the working surface of the die 2 said cylinder 1 and the compressed gas chamber 8 are closed off by a cover 10, and the compressed gas chamber 8 is closed off by a ram. The actuator 4 selectively communicates with the upper chamber 6 and drives the ram 3 toward the die 2, and the ram home position return means returns the ram 3 to its home position. a closed chamber 14 communicating with the lower chamber 5;
A valve 17 selectively communicates the ram upper chamber 6 with the atmosphere, and a closed chamber 14 is provided on the wall of the cylinder 1 at a distance approximately equal to the thickness of the ram 3 from the end of the cylinder 1 facing the die 2.
The closed chamber 14 is arranged flush with the cylinder 1 at the end of the cylinder 1 close to the die 2, and the wall surface of the cylinder is
A hydraulic punch for a press, which has a passage 16 that communicates a ram lower chamber 5 with an interior 15 of a closed chamber 14, and the actuator 4 is equipped with a cam 19 for closing or opening the valve 17. 2 comprises a cylinder 1 whose one end faces the working surface of the die 2 via a high-pressure chamber 11 filled with fluid as a working medium, in which a ram 3 is movably disposed; Ram upper chambers 6 are provided above and below the ram 3, respectively.
, a ram lower chamber 5 is formed, a compressed gas chamber 8 is arranged around the cylinder, and at the end remote from the working surface of the die 2 said cylinder 1 and the compressed gas chamber 8 are closed off by a cover 10, in which the compressed gas an actuator 4 for selectively communicating the chamber 8 with the ram upper chamber 6 and driving the ram 3 toward the die 2;
The ram home position return means includes a ram home position return means for returning the ram 3 to its home position, and the ram home position return means includes a closed chamber 14 that communicates with the ram lower chamber 5 and a valve 17 that selectively communicates the ram upper chamber 6 with the atmosphere. and a check valve 20 provided on the wall of the cylinder 1 at a distance approximately equal to the thickness of the ram 3 from the end of the cylinder facing the die 2 so as to introduce gas into the closed chamber 14. 14 is cylinder 1 close to die 2
The actuator 4 closes or opens the valve 17, and the wall of the cylinder has a passage 16 which communicates the ram lower chamber 5 with the interior 15 of the closing chamber 14. A hydraulic punch for a press, further comprising a check valve 21 for introducing compressed gas into the high pressure chamber 11 filled with fluid as a working medium.