JP3295115B2 - Hydro-elastic deep drawing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydroelastic deep-drawing device for a press for drawing a thin-plated part, which is supported by a hydraulic pressure cylinder via a drawing pin. A plate and a punch movably guided in the throttle direction are provided, the punch being supported by at least one piston loadable by a hydraulic medium guided in the cylinder; A cushion plate of the type is provided, and a mechanical throttle pin is arranged in the hole arrangement area of the table plate through the hole corresponding to the die shape and supported by a common cushion plate. And wherein the cushion plate is reciprocally held by one or more hydraulic adjustment members.

[0002]

BACKGROUND OF THE INVENTION In the case of metal deformation for producing sheet metal parts which are to be deep drawn, it is known in tooling technology systems to use drawing pins to support a sheet holding plate. The aperture pin acts as a spacer pin to form a pressure pin between the thin plate and the cushion. The draw pins are the required key components of each deep drawing tool, i.e. the length and number of draw pins are tool dependent.

A drawback of this mechanical draw pin is that the draw pin wears and, in the case of a rigid holding mechanism, leads to uncontrolled and uneven plate holding forces during operation, which leads to undesired folding of the molded parts. Part is to occur. This disadvantage is avoided by the elastic holding member by inserting a rubber plate.

DE 32 22 844 B1 discloses a deep-drawing device for presses or tools for drawing sheet-metal parts, which deep-drawing device has a large number of supporting plates for supporting a sheet-holding plate. Another cushion having a cushion consisting of a pressure cylinder and a piston loaded by a flow pressure medium movably guided axially in the pressure cylinder and receiving a punch movably guided in the throttle direction The pressure cylinder of this cushion is connected via a flow path to the pressure cylinder of the cushion used as a support for the sheet holder and is loaded by a flow pressure medium which is displaced from the pressure cylinder during the drawing process. You.

In this deep drawing apparatus, the pressure medium flowing out of the pressure cylinder of the cushion used as a support for the sheet holding member when the die operated by the press ram is lowered receives the punch in a vertically movable manner. It is important that the pressure cylinder of another cushion overflows via a conduit and loads the piston guided in the pressure cylinder of this cushion, in which case the piston itself dices the punch during the drawing process. And, it is driven in the drawing direction against the movement direction of the thin plate holding plate. The resulting direct flow connection between the pressure cylinder of the punch / working section and the pressure cylinder of the sheet holding plate / working section forms a so-called pressure balance.

One of the disadvantages of mechanical draw pins has been avoided with this known deep drawing apparatus.

The drawbacks of this known deep drawing apparatus include the following.

[0008] The generated force cannot be reproduced. This is because there is an association between drawing speeds based on different flow resistances, i.e. this deep drawing device is not suitable for carrying out the process via a computer program.

The force profile during the deformation of the sheet is approximately parabolic from the beginning to the end of the deep drawing process. Particularly in the case of flat drawn parts or in the case of complex shaped parts or geometric shapes, it is always necessary to control the high sheet holding force from the beginning in the special operating range of the sheet holding area as desired.

[0010] In order to avoid this drawback, DE-A 33 33 687 discloses a pressure control valve which is housed together, so that the pressure holding valve can be used to connect the sheet holding member to the punch. In the oil flow, different pressures can be set, for example, from the outset or essentially over the entire drawing process.

In this case, the following disadvantages are associated with such control in practice: a) The oil is compressed differently under different pressure conditions in the working section, the sheet carrier and the working section, the punch. A hydraulic pressure peak occurs, which further destroys the lubricating film surface texture.

B) The pressure control valve causes oil leakage and consumption.

C) It is not possible to obtain a reproducible process or production process based on the conditions according to a) and b), that is, it is not possible to carry out the process accurately.

[0014] The flow connection in both of the above-mentioned prior art examples usually has the disadvantage that the punch / stroke position cannot be accurately and reproducibly controlled based on oil compressibility and leakage.

[0015] In order to avoid the disadvantages of the rigid holding mechanism, according to DE-A 32 42 705, it is furthermore necessary to compensate the tilting position and to apply individual forces to the dies at least at the corners. It is also known to provide a cushion mechanism that is supported at four points and is force-adjusted independently of each cylinder. Disadvantageously, however, it is not possible to compensate for the deflection in the cushion plate between these (1-4) points of force application and to obtain a synchronous movement on return of the mechanism, for example at the discharge position.

In order to avoid this drawback, EP 0 268 894 and DE 380
No. 7,683,831 furthermore, a plurality of hydraulic or pneumatic support cylinders for the sheet-holding plate are further connected at the center via a mechanical cross beam and the cross beams are moved in a further synchronous manner. It is known to control the function by means of individual central hydraulic supports.

The disadvantages of such a mechanism are that the mechanical cost is high and in the case of central adjustment, for example, when the workpiece is ejected, a tilting movement occurs due to eccentric force effects. However, this tilting movement can only be limited and perceived by adding additional mechanical guidance costs.

[0018]

SUMMARY OF THE INVENTION It is an object of the present invention to avoid the above-mentioned disadvantages and to arrange the sheet-holding plate / working section and punch / working section according to the shape of the workpiece and according to the hole pattern. A precise force profile and adjustment without disturbance amplitude can be achieved and the advantages and effects of a rubber-elastic cushioning mechanism can be obtained, so that a computer-assisted, process-accurate process can be used. The object is to improve a hydroelastic deep drawing device of the type mentioned at the outset.

[0019]

According to the present invention, the above-mentioned object has been achieved by an arrangement according to the characterizing part of claim 1.

[0020]

The arrangement according to the invention, in particular, together with the advantages and possibilities of computer-assisted process control, provides a rubber-elastic sheet carrier / cushion mechanism for multiple working sections of the sheet carrier plate and punch. Behavioral benefits can be obtained.

According to the invention, it is not necessary to provide separately controlled valves for each individual cylinder, but rather for a large number of hydraulic cylinders in a very small space in a process-accurate and computer-assisted manner, ie with the same program. It can be operated equally repeatably.

The hydraulic multi-point deep-drawing device according to the invention in combination with a short-stroke, multi-cylinder mechanism is advantageously used in both hydraulic and mechanical (crank) deep-drawing devices. it can.

Other advantages are as follows.

1) Since each mechanical throttle pin is supported by a hydraulic cushion in the range of the force acting section, the effect of the rubber-elastic cushion and the effect of the uniform force acting around the die can be achieved. Is automatically compensated for.

2) At the same time, it is possible to automatically compensate for the tilt corresponding to the angle α resulting from the tilting of the cushion plate or the ram, for example, by applying a uniform pressure in the technical manner.

3) German industrial standard = between 150 mm holes
Starting from the spacing dimension , the spacing dimension of this hole can be chosen to be very small, for example about 3 = a = b = 37.5 mm
And below, so that the effect of a virtually rubber-elastic mechanism is obtained.

4) The short-stroke piston is integrated into the so-called force section with fixed perforations or tubular parts in the cushion plate itself. In this case, the arrangement of the force acting section under the cushion plate can be selected arbitrarily by using an external hydraulic force acting block in connection with a flexible hose and the arrangement is of die-shaped The hose for each short-stroke piston can be pluggably arranged in the cushion plate itself.

5) Each short stroke piston is
Depending on the hole spacing dimensions a, b, it can be integrated into the mounting plate, in which case the mounting plate is divided into large hole arrangement areas over the entire cushion surface. The mounting plate is form-locked to the cushion plate via screw connection members. Since a return spring is assigned to each short-stroke piston, a mechanical null position is always obtained on the cushion-support surface of the cushion plate.

6) The short stroke piston itself can be provided with an additional centering member, for example for centering a mechanical throttle pin.

7) The force application section is servo-hydrically adjusted over the throttling stroke, taking into account precise force profile control.

8) When an eccentric force distribution occurs on the cushion plate due to different force actions in the force action sections, the cushion plate becomes inclined, ie, at each limit position, the angle α If the plate is supported centrally via a central hydraulic cylinder, it can be enlarged or the cylinder can be hydraulically connected in multipoint support and the cushion plate can be sufficiently mechanical If you are not informed,
Decrease.

The differential cylinder / piston device acting at the four corners of the cushion plate enables synchronous operation control of the cushion plate and the thin plate holding plate during passive and active drawing, and all four.
The two cylinders are servo-hydraulic adjusted by synchronous operation (parallel operation) during the deep drawing stroke, and during synchronous operation the mechanism is hydraulically tensioned under pressure in order to compensate perfectly for oil compression errors.

The respective stroke position is adjusted and controlled according to the tool requirements, and a parallel return of the sheet holding plate is obtained after deep drawing. In this case, the return process is
It can be performed at high speed according to a pre-programmable speed profile (acceleration and braking) to release the drawn part.

In this case, advantageously, the short-stroke cylinder-piston arrangement automatically compensates for adjustment errors during synchronous operation. More advantageously, the short-stroke cylinder-piston arrangement is servo-hydraulic controlled for rapid movement, with little oil volume and low cost and with high precision, virtually no compression volume.

With the deep drawing apparatus according to the invention, existing tools conventionally used for mechanical drawing pins can be universally used without modification in this hydraulic deep drawing apparatus, In this case, the possibility of very high process accuracy of the servo-hydraulic control is obtained and, due to the use of different method steps, for example, for the usual displacement, switching from deep drawing to opposed deep drawing, An advantageous and large use spectrum is enabled.

The possibility based on the process accuracy of the method for controlling the deep drawing process according to the invention is particularly important for the quality assurance of the deep drawn products produced. Obstructive effects, such as tilting of the press ram or non-parallelism of the tool, are effectively compensated for by a given hydraulic short-stroke, multi-point support mechanism, whereby the occurrence of folding is perfectly prevented.

When a different force is controlled for each force action section, the center of gravity of the force surface in the cushion plate changes. This eccentric force acting on the cushion plate is immediately and automatically received by the differential cylinder positioned at the four corners.

[0038]

1 to 13 show various embodiments of the deep drawing device of the press 1, partly in an open working position and partly in a closed working position. The upper beam with ram 2 is provided with a tool change plate with dies 4.

FIGS. 1 to 8 show a hydraulic cushion 31 in a conventionally known structure type, and this cushion 31 is a table plate 6 surrounding the shape of the die 4.
Is inserted into the hole in the hole array in the area has a mechanical throttle pin 13 which is placed. The throttle pin 13 is further supported by a common cushion plate 8, in which case the cushion plate 8 has four hydraulic adjustment members 3,
14 is supported. The adjusting members 3, 14 are fixedly connected to the substrate 9 of the press frame.

The cushion plate 8 has a hole
Hydraulic short-stroke piston-cylinder mechanisms 10, 23, corresponding to the hole arrangement areas having the separation dimensions a, b ,
28 and 35 are provided. In this case, the stroke H of the short stroke pistons 10, 23 is only a few mm, for example, only 10 mm at the maximum.

Each throttle pin 13 is further supported by a short-stroke piston 10 or 23 and has a centering recess 34 of the short-stroke piston 10 or 23.
It is supported within. Short stroke piston 10
And 23 are integrated, for example, in the force-acting sections 21, 22 for the lamination plate 12 and / or the punch 5,
In this case, the force acting section is connected via a cylinder 35 to a fixed perforated or tubular part in the cushion plate 8 according to FIGS.

By means of the flexible hose 25 and the plug-in connection member 15, the arrangement of the force acting sections below the cushion plate 8 can be arbitrarily selected via an external hydraulic force acting block. The individual short-stroke piston-cylinder arrangements are integrated in the mounting plate 24 according to the hole spacing dimensions a, b, wherein the individual mounting plate 24 has a large hole arrangement over the cushion surface.
Divided into areas . The mounting plate 24 is shape-fixed to the cushion plate 8 via the screw connection member 16.

Each short stroke piston 1
Since a return spring 17 is assigned to 0, 23, 28, 35, a mechanical zero position is always available on the cushion plate support surface 19 of the cushion plate 8 or the short-stroke pistons 10, 23, 28, 35 35
Is held in a neutral central position by a return spring 17 for ± compensation.

The cushion plate 8 is hydraulically supported by one cylinder 14 at each of the four outer corners. All four cylinders are hydraulically adjusted during the deep drawing stroke by synchronous operation (parallel operation), the four cylinders being adjusted in parallel operation being configured as differential pistons 3.

FIGS. 3 and 4 show a variant embodiment of the multi-point support, short-stroke piston-cylinder mechanism, in which the mechanical throttling pins 13 are grouped, for example according to the force action section. Segmented and supported by a large short-stroke piston 10,
Each of the short stroke pistons has a rectangular support plate 11.

FIGS. 5 and 6 show a variant embodiment of the short-stroke piston-cylinder mechanism with large hole spacing dimensions a and b, in which case, for example, a deep drawing performed downward. An additional opposing cylinder 33 is arranged in the center in order to allow the punch to act in opposition to the passive sheet holding member against the machining movement.

FIGS. 7 and 8 show eight force action sections I.
FIG. 6 illustrates a variant embodiment of FIG. 5 with -VIII.

FIG. 9 shows a multi-point support / mechanism having a short stroke piston 9 which is fixedly arranged on the table plate 6. Tool holding plate 1
2 is mounted on the table plate 6 in a force-coupled manner by its own weight in the open state of the press and on the short-stroke piston mechanically returned to the zero position by the return spring 17.

The stationary arrangement of the multipoint support and mechanism on the table plate 6 makes it possible to use one or more hydraulic punches 5 which are stationary below the table plate 6 and which are vertically mounted. Punch movement from below in the direction is possible. Thus, such an arrangement advantageously allows the use of a simple down-stroke press with the following advantages.

1) In the inclined position shown in FIG. 1 with various angular positions based on the inclination of the ram 2 or the cushion plate 8, the ram is forcibly formed into a planar die 4.
This does not occur if the ram is configured to be supported by the ram and the ram moves.

(B) The multi-point support / mechanism 29 can be arranged in the same manner with the force action sections and the hole spacing dimensions a and b according to FIG. 1, and similarly, the various force action sections 21 and 22.

FIGS. 10 and 11 illustrate the stationary arrangement of the multipoint support / mechanism similar to FIG. 9, but are new and different in the following respects.

That is, the distance between the small holes similar to FIG.
Instead of providing a large number of short-stroke pistons according to the methods a and b, in this embodiment a large short-stroke piston unit 10, 11 corresponding to the force application section.
Is provided.

In FIGS. 12 and 13, the upper ram 2 is used when it is used as a double-acting press acting from above.
3 shows a modified embodiment of a short stroke piston arrangement type as a multi-point support / mechanism in the inside. In this case, the arrangement of the short stroke piston is the small hole in Fig. 1.
Is implemented by means of a large short-stroke piston 10 which is sectioned according to the spacing dimension of the piston or according to the force application section. Reference numeral 2 'shows the outer ram.

Notes on the arrangement with movable cushions: The cushion plate 8 is supported hydraulically and passively moves vertically from top to bottom by active ram movement. The return of the cushion plate 8 is actively performed upward at any position. In this case, in the field, two positions at which the movement starts with the upward movement are obtained.

The upper dead center position indicated by reference numeral 26 in FIG. 3 indicates the height of the upper dead center of the punch 5.

[0057] upper position of the position 26, for example, the position of the discharge station is indicated by reference numeral 27.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a deep drawing apparatus according to the present invention.

FIG. 2 is a view showing a part of the cushion plate of FIG. 1;

FIG. 3 is another embodiment of the deep drawing apparatus shown in a press closed state.

FIG. 4 is a view showing a table plate having the hole pattern or the hole arrangement area shown in FIG. 3;

FIG. 5 is a diagram of a third embodiment of the deep drawing apparatus.

FIG. 6 is a view showing a table plate having the hole pattern or the hole arrangement area shown in FIG. 5;

FIG. 7 is a diagram of a fourth embodiment of the deep drawing apparatus.

FIG. 8 is a view showing a table plate having the hole pattern or the hole arrangement area shown in FIG. 7;

FIG. 9 is a diagram showing a fifth embodiment of a deep drawing apparatus having a short stroke piston fixedly arranged on a table plate.

FIG. 10 is a drawing of a sixth embodiment of a deep drawing apparatus having a short-stroke piston fixedly arranged on a table plate.

FIG. 11 is a plan view of the table plate of FIG. 10;

FIG. 12 when used as a double press.
And a diagram showing the deep drawing apparatus of FIG.

FIG. 13 is a plan view of the table plate of FIG. 12;

[Explanation of symbols]

1 press, 2 ram, 3,14 adjusting member, 4
Dice, 5 punches, 6 table plates,
8 Cushion plate, 9 Substrate, 10, 23
Short stroke piston, 12 Thin plate holding plate, 13 Aperture pin, 14, 35 cylinder, 1
6 screw connecting member, 17 return spring, 21, 22 force action section, 24 mounting plate, 31 cushion,
33 opposed cylinder

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Manfred Kreuzwieser German Federal Republic of Germany Sinsheim K. Werberg 29 (56) References JP-A-4-367327 (JP, A) Japanese Utility Model Application No. 64-54919 (JP) , U) Shokai 60-176821 (JP, U) Shoko 46-33838 (JP, Y1) (58) Fields investigated (Int. Cl. ⁷ , DB name) B21D 24/02 B30B 15/02

Claims (11)

(57) [Claims] 1. A hydroelastic deep drawing device for a press for drawing a sheet metal part, comprising: a sheet holding plate supported by a hydraulic pressure cylinder via a drawing pin; A movably guided punch, at least one of which can be loaded by a hydraulic medium guided in a cylinder.
One of which is supported on the piston, further, it is provided with a cushion plate hydraulically, mechanically diaphragm pin corresponds to the die shape with a hole arrangement area of the table plate hole
, And supported by a common cushion plate, wherein the cushion plate is held in a reciprocating manner by one or more hydraulic adjustment members, i. A cushion plate (8) provided with a multi-point support / control mechanism corresponding to the shape of (7) is provided, and inside the cushion plate, a hole pattern or a hole arrangement area having a distance of dimensions a and b is provided. Correspondingly, at each target point (20), a hydraulic short-stroke piston (23) with a pluggable throttle pin (13) is assigned, the stroke of the short-stroke piston being up to 10 mm. B) Each short stroke piston (23)
In each case, one short-stroke cylinder (3) with a hydraulic force-acting section (21, 22) which can be selectively connected to the workpiece or the sheet-holding plate (12).
C) the cushion plate (8) is supported by four differential corner piston mechanisms (3, 14), each of which is hydraulically aligned at four outer corners, in parallel. D) The multi-point position adjustment of the differential cylinder piston mechanism (3, 14) based on appropriate control,
A hydroelastic deep drawing apparatus characterized in that an eccentric force when the center of gravity of the force surface of (1, 22) changes is automatically received hydraulically. 2. The short-stroke piston (23) is cushioned against a force application section (21, 22) by a fixed perforated or tubular part in the cushion plate (8) itself or via a plug-in connection (15). 2. The deep drawing apparatus according to claim 1, wherein the lower side of the plate is connectable by a flexible hose. 3. An individual short-stroke piston (2).
3) can be integrated into one or more mounting plates (24) corresponding to the spacing (a, b) of the holes (20) , the mounting plates (24) being on the cushion surface and in the large hole arrangement area . 3. The deep drawing device according to claim 2, wherein the device is divided and can be fixed in a form-locking manner by means of a screw connection. 4. The short-stroke pistons (23) are each assigned a return spring (17), and the short-stroke pistons are each provided with a centering recess for a throttle pin (13) on the upper surface. The deep drawing device according to claim 1, wherein: 5. A plurality of throttling pins (13) which are integrated in groups and which are sectioned according to the force application section and which are supported by a large short-stroke piston (10) and each have a rectangular support plate (11). 5. The method according to claim 1, further comprising the steps of:
The deep drawing device according to the item. 6. The device according to claim 1, wherein eight force-acting sections are provided for the sheet-metal holding plate and one central piston-cylinder arrangement for the workpiece is provided. Any one of claims 1 to 5
The deep drawing device according to the item. 7. Only one powerful throttle pin (13) with a large short-stroke piston (28) for each sheet-holding plate / force-acting section and one central in the center for the workpiece. 7. The deep drawing device according to claim 1, wherein an opposing piston cylinder device (5, 32, 33) is provided. 8. An opposed piston cylinder device (5, 32,
33), the short-stroke piston-cylinder mechanism (29, 17, 23, 33) is fixedly integrated in the table plate (6), and the thin plate holding plate (12) of the tool is transmitted by its own weight with the press released. 8. The deep drawing device according to claim 1, wherein the deep drawing device is mounted on the table plate and the short-stroke piston in a force-connected manner. 9. 9. The short-stroke piston-cylinder mechanism (10, 11) is housed in an outer ram (2 ') and is connected to a die (4). 9. The deep drawing apparatus according to any one of 8 to 8. 10. A control mechanism for adjusting the position of the four differential cylinder piston devices (3, 14) in parallel with the servo-hydraulics and for hydraulically tensioning the mechanism under pressure during synchronous operation is provided. The deep drawing device according to claim 1, wherein: 11. A return spring (1) to hold the short stroke piston in a neutral center position for ± compensation.
The deep drawing device according to any one of claims 1 to 10, further comprising a control mechanism for setting the spring constant according to (7).