JPH0133254B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a means for high speed forming of metal, and more particularly to an apparatus for impact sheet forming.

The present invention is a press using a hydrodynamic method of high-speed thin sheet processing with a flexible medium, i.e. blanking, stamping, embossing, with a small amount of deformation of the thin sheet,
It can be advantageously used in developing presses suitable for processing in forming, shallow drawing and other similar operations. Further, the present invention can also be applied when processing a high-strength thin plate that is difficult to deform and includes a heat-treated material.

One method that can solve metal forming problems with a flexible medium is rubber pad forming. Related equipment uses a rubber pad placed in a container to transmit strokes to a rigid forming tool on which the blank rests, and the kinetic energy of the parts that move together with the rubber pad forms the blank (see e.g. EA
Butuzov “Spetsialnye vidy shtampovki”, Moscow, 1963, p.60).

The disadvantages of said device are the inability to generate high-velocity shocks in flexible media and to establish pressure peaks. For this reason, these devices can be used to form high-strength materials that are difficult to deform.
and cannot be used to perform operations such as embossing, sizing and bulges associated with creating small radius curvatures.

Also known is a device that forms a rubber pad by accelerating a fine hammer-shaped tool to a speed of several tens or hundreds of meters per second and then pressing it against the surface of the part being formed (see, for example,
“Kuznechno−shtampovochnoe
proizvodstvo” No. 9, 1973, Moscow, EF
Ankirsky and others, “Udarnaya shtampovka
“Rezinoi”, p.20).

The disadvantage of this device is that the efficiency of utilizing the kinetic energy of the hammer is low. This is because the shock wave reflected from the blank is not reflected from the flexible medium as it is reflected from a screen, and the energy of the shock wave is not concentrated on the blank so as to work to shape the blank. This is because you will pass through it and move on. Apart from that, since the moment of impact with the blank forces the hitch of the known device into the outlet passage connecting the bore of the pressure sleeve with the atmosphere, mechanical destruction of the hitch occurs rapidly.

Furthermore, a pressure sleeve is incorporated with one end facing the shaping surface of the die, and has a hammer that moves within the pressure sleeve so as to form a space above and below the hammer. Apparatus for hydrodynamic forming, including impact sheet forming, are known. The space above the hammer is connected to a receptacle containing a compressed gas, for example air. A high pressure chamber containing a flexible pad is located at the end of the pressure sleeve facing the die. A hammer is arranged to interact with means for actuating the hammer and means for returning the hammer to an initial position. The means for returning the dowel to its initial position are provided with a closed annular chamber communicating with the space in the bore of the pressure sleeve below the dowel, the closed annular chamber having an end facing the die. (see, for example, Published Application of the Federal Republic of Germany, No. 3001243, B21D26/02, 1980).

The disadvantage of this device is that the flexible pad breaks down rapidly, resulting in low operational reliability. Shock compression of flexible pads due to high velocity impacts that produce adequate molding pressures is known to be accompanied by a sudden rise in temperature similar to thermal shock. In the presence of oxygen in the air driven out of the pressure sleeve by the hammer, the material of the pad begins to burn at the surface under the impact load, melting and eventually pulverizing. The temperature increase in the contact area between the impacting objects is facilitated by the pulsating compression of the thin layer of air contained in the microspace between the hammer and the flexible pad. The hotter combustion process becomes progressively more intense as more air is now trapped in the cavities formed in the pad by combustion of the pad material and compressed by the next impact. This condition causes the pad to thermally fail rather quickly. Thus, at a speed of about 50 m/s, the polyurethane pad only lasts 60-70 strokes, and at higher speeds it fragments more quickly.

The main object of the invention is to provide an apparatus for impact sheet forming which eliminates the possibility of thermal failure of the flexible pad by removing heat from the flexible pad at the moment of impact.

To achieve the above objective, the die is provided with a pressure sleeve facing the forming surface of the die at one end, the pressure sleeve having a pressure sleeve inside the pressure sleeve so as to form a space above the shot and a space below the shot. a high-pressure chamber containing a pliable pad and located next to the end of the pressure sleeve facing the die; means for actuating the hammer and means for returning the hammer to an initial position having a closed chamber, the closed chamber being a pressure sleeve below the hammer. In an apparatus for impact sheet forming, which is located at the end of the pressure sleeve communicating with the interior space and facing the die, according to the invention: That is, means are provided for supplying a metered amount of liquid into the space below the hammer, which means act synchronously with the means for actuating the hammer and into the space between the hammer and the flexible pad. What is necessary is just to arrange it so that a liquid is supplied.

The means for supplying the liquid may be arranged inside the closed chamber of the means for returning the hammer to its initial position.

Conveniently, the means for supplying a metered amount of liquid incorporates a plunger-type pump connected to a nozzle with a spring-loaded valve, and all said components are housed in a single housing.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below with reference to embodiments.

In FIG. 1, the apparatus for impact sheet forming has a pressure sleeve 1 facing at one end the forming surface of a die 2 of a hydrodynamic press. The bore of the sleeve 1 contains a dowel 3 which interacts with means 4 for actuating it and means for returning the dowel 3 to its initial position. When moving within the sleeve hole, the hammer 3 forms a space 5 and a space 6 located below and above it, respectively. The collet 7 serves to keep the hammer 3 fixed in its uppermost position. The device also incorporates a receptacle 8 with compressed gas, which is located concentrically with the pressure sleeve 1 and connects the space 6 in the sleeve 1 above the hammer 3 and the passage 9. communicated through. A cover plate 10 closes off the bore of the pressure sleeve 1 and the interior of the receptacle 8 .

The end of the pressure sleeve 1 facing the die 2 is in contact with a high pressure chamber 11, in which a flexible pad 12 is placed.
is accommodated and this pad transfers the energy of the hammer 3 to the blank 13 above the die 2.

The means for returning the hammer 3 to its initial position are provided by a closed chamber 14 located at the end of the pressure sleeve 1 facing the die.
and a valve 17 attached to the cover plate 10. A space 15 in the closed chamber 14 is connected to the space 5 of the pressure sleeve 1 via a passage 16 and a valve 17
is connected to the space 6 in the pressure sleeve 1 and to the atmosphere via a passage 18. A lever 19 connected to a piston rod (not shown) of the means 4 for actuating the hammer 3 is used to open the valve 17.

According to the invention, the device is provided with means 20 for supplying a metered amount of liquid into the space 5 below the hammer 3, which means act synchronously with the actuating means 4 of the hammer 3. . This purpose is fulfilled by a solenoid-operated pneumatic valve 21 which controls the operation of the means 4 via lines 22, 23 and at the same time checks the means 20 via lines 24, 25. confirm. A liquid, which is a mixture of water and a corrosion inhibitor or a corrosion inhibiting lubricating coolant (to which the water is added is mineral oil and an emulsifier), is stored in a tank 26 and passes from the tank to the means 20 via a line 27.

In FIG. 2, means 20 include housing 28
It consists of a plunger type pump having a piston 29 and a plunger 30 included in the pump. Housing 28
Passages 31, 32 and 33 provided in are connected to conduits 27, 24 and 25, respectively. A passageway 35 connects the space 34 to a nozzle with a tip 36 having a space 37 and a passageway 38 . This nozzle is also provided with a valve 39 and a spring 40.

The check valve 41 (Fig. 1) controls the used gas.
It serves to convey from the space 6 above the hammer 3 into the closed chamber 14.

The apparatus for impact sheet forming operates as follows.

FIG. 1 shows the state in which the hammer 3 is at the end of its stroke returning to its initial position when the passage 9 is closed, and the valve 17 is opened and the compressed gas contained in the space 15 moves the hammer 3 upward. Moving. At the end of the upward stroke, tap 3
engages the collet 7 and remains fixed there, dissipating its kinetic energy. In order to start the stroke of the hammer 3, compressed gas is introduced into the line 22 by means of a solenoid-operated pneumatic valve 21, and the piston rod (not shown) of the means 4, which exposes the passage 9, is displaced upwards. The lever 19 disengages the valve 17, so that the space 6 of the pressure sleeve 1 is disconnected from the atmosphere. Once the passage 9 is opened, the compressed gas entering the space 6 of the pressure sleeve 1 from the receiving part 8 accelerates the hammer 3. At the same time, the compressed gas reaching the means 20 via the line 24 enters the passage 32 and acts on the piston 29, so that the plunger 30 compresses the liquid contained in the space 34 and transfers it via the passage 35. Tip part 36
into the space 37. The pressure of the liquid increases,
As soon as the point is reached which causes the valve 39 to leave its seat and be displaced to the right against the action of the spring 40, a metered amount of liquid flows through the passage 38 into the space 5 under the stud 3 of the pressure sleeve 1. is injected into.

Prior to the machining process, hammer 3 with a flexible pad 12
During the approach, the ejected liquid spreads into a thin layer over the surface of the flexible pad 12 facing the hammer 3. As it heats up and evaporates, the liquid absorbs some of the heat released during shock compression of pad 12. The heat of vaporization of the liquid is removed from the flexible pad 12 by injecting an amount of liquid corresponding to the heat removed from the flexible pad 12.
The temperature of the surface of pad 12 must be maintained at a level below the softening point of the material of pad 12. Apart from this, the thin layer of liquid present on the surface of the pad 12 at the moment when the hammer 3 approaches the pad 12 protects the material of the pad 12 from the oxygen in the air displaced by the hammer 3. Helps insulate.

Upon reaching the lowest position, the hammer 3 strikes a flexible pad 12 whose surface is now covered with a thin layer of liquid, forming a blank 13 as specified by the die 12. When the liquid heats up and evaporates in response to the impact load, it forms a flexible pad 12.
This removes some heat from the pad and prevents the pad 12 from being destroyed.

When the hammer 3 is on its downward stroke, the gas displaced from the space 5 of the pressure sleeve 1 enters the space 15 of the closed chamber 14. At the end of the stroke, more gas, in this case the spent gas expelled from the space 6 of the pressure sleeve 1 via the check valve 41, enters the space 15.

In order to return the hammer 3 to its initial position, a solenoid operated pneumatic valve 21 introduces compressed air into the cylinder of the actuating means of the hammer 3 via a line 23. As a result, passage 9 is closed, but lever 19 is closed to valve 17.
is pressed open and the space 6 above the stud 3 of the pressure sleeve 1 is connected to the atmosphere via the passage 18. The compressed gas contained in the space 15 forces the hammer 3 upwards and engages it with the collet 7.

At the same time, a solenoid-operated pneumatic valve 21 admits compressed gas via line 25 into passage 33 of means 20. As a result, the piston 29 integral with the plunger 30 is displaced to the right, so that the space 34 is filled with liquid and the valve 39 covers the passage 38 under the action of the spring 40.

The machining cycle is now complete and the device is ready for further operation.

The disclosed construction of the device significantly extends the life of the flexible pad, reduces the time required for pad replacement, and improves device reliability. It is appropriate to state that the flexible pad of the known device, which does not inject liquid into the space of the pressure sleeve under the hammer, broke down after 60-70 strokes. However, by injecting a calculated amount of cutting fluid using the means 20 before each machining stroke, the device can be
It was able to operate for 7,500 to 8,000 cycles without damage.

[Brief explanation of drawings]

FIG. 1 is a general sectional view of an apparatus for impact sheet forming according to the invention, and FIG. 2 is a longitudinal sectional view of a means for supplying liquid according to the invention. DESCRIPTION OF SYMBOLS 1... Pressure sleeve, 2... Die, 3... Hammer, 4... Means for operating the hammer, 5... Space under the hammer, 6... Space above the hammer, 8... Receiving part, 11... Hyperbaric chamber, 12... Flexible pad, 1
3...Blank, 14...Closed room, 20...
...means of dispensing a metered amount of liquid.

Claims (1)

[Claims] 1 a die; a hollow pressure sleeve disposed upward from the molding surface of the die; a hammer disposed vertically slidably within the pressure sleeve; a lower end of the pressure sleeve a flexible pad disposed above the forming surface of the adjacent die for transmitting impact energy of the hammer to a thin plate disposed on the forming surface of the die; attached to the top of the pressure sleeve;
An apparatus for impact thin sheet forming, comprising: a hammer operating means for operating a hammer having a collet for fixing the hammer; and a hammer return means for returning the hammer to the position of the hammer operating means; The device further comprises: a liquid jet orifice disposed on a surface of the flexible pad facing the space below the hammer in the pressure sleeve;
Equipped with a mechanism that controls opening and closing of this liquid injection port,
a liquid supply means for supplying a fixed amount of liquid into the space under the hammer; a liquid storage tank disposed in communication with the liquid injection port; an opening/closing control mechanism for the hammer actuation means and the liquid supply means; An apparatus for impact thin plate forming, comprising: a pneumatic valve that controls the flow of supplied compressed working gas and operates a hammer operating means and a liquid supply means in synchronization.