EP2103423B1 - Powder moulding press for producing a pressed product from metal powder - Google Patents

Abstract

The lower plunger assembly (1) is equipped with a plate (2) on which the matrix assembly (3) is fitted. Transverse pressing units (4) are also attached to the plate (2). Each has a transverse pressing plunger (5) connected to a linear drive. Each plunger enters an opening (6) into the molding cavity (8) of the matrix (7). It can be pressed in and retracted, transverse to the main pressing direction. A linear drive is used with each transverse pressing unit. The linear drive has a fixed component fastened to the frame and a part moved linearly relative to the fixed component. This is connected to a wedge. The latter has a wedge surface acting on the wedge surface of a second wedge. This wedge is moved essentially at right angles to the first wedge, in a transverse direction. The two wedges are moved along linear guides fitted to the frame of the transverse pressing unit. The pressing position reached by the transverse plunger (5) is limited by an adjustable stop. This is a third wedge which is adjusted transversely with respect to the direction of movement of the first wedge, guided in the frame. It acts against a further wedge surface of the first wedge. The position of the transverse plunger in relation to the matrix assembly is detected by measurement sensors and transmitted to the control unit. Each transverse press plunger is held by a coupler in the respective transverse pressing unit. The transverse pressing unit has a peg projecting into one of a number of bores in the plate, when mounted upon it. Several transverse pressing units can be fitted to the same plate in this way. The bores in the plate are associated with corresponding tapped bores for clamping screws. These are held in suitable recesses in the frame of each transverse pressing unit. The recesses are slot-shaped.

Description

The present invention relates to a powder press for producing a metal powder compact having an upper punch assembly, a lower punch assembly, and a die assembly forming the mold cavity, into which the metal powder is insertable, and then the upper punch assembly and the lower punch assembly to form the compact can be pressed against each other in the pressing direction, controlled by a control unit, and the lower punch assembly is provided with a plate on which the die assembly is mounted, and on which plate transverse pressing devices are mounted, which are each equipped with a transverse punch, softer linearly driven by a drive is and can be withdrawn through an opening in the die substantially transversely to the pressing direction in the transverse pressing direction into the mold cavity in a pressing position and retractable from this.

Such powder presses are known in many ways, they are used to produce powder compacts, which are then sintered, whereby a variety of workpieces can be produced, which can meet the most diverse requirements for these workpieces in the most optimal manner, for example, indexable inserts are made in this way, the very be exposed to high loads. In powder pressing of cemented carbide or other materials, pressing is primarily in a pressing direction, which is usually vertical.

There are also powder presses are known in which transverse dome are introduced through the Matrizenwandung transversely to the pressing direction in the mold cavity before the pressing process, which usually come to a punch of the lower punch assembly to the plant. These transverse mandrels are moved by direct linear drives, for example hydraulically, which is possible because these transverse domes do not have to absorb any pressing forces in their direction of movement.

The object of the present invention is to design the powder press in such a way that the compact can also be deformed during the pressing process with transverse compression punches and the forces occurring during the pressing can be absorbed in the transverse pressing direction.

According to the invention, this object is achieved in that the drive of each transverse pressing device comprises a linear drive with a fixed part attached to the frame of the transverse pressing device and a part which can be displaced linearly relative to the fixed part, which linearly displaceable part is connected to a first wedge whose wedge surface the wedge surface of a second wedge acts, which is displaceable substantially perpendicular to the first wedge in the transverse pressing direction.

With this embodiment of the invention, it is possible to produce transverse bores in a compact of metal powder, but it can also lateral recesses are produced in this compact, which are not continuous, so that the cross pressing device can absorb the forces occurring during pressing in the transverse pressing direction. The passages for the cross press dies may be obtained by recesses mounted in the annular die form, but the inner part of the die assembly may also be fully split or partially split, these die parts being spaced from each other, around the recesses for the passages of the cross press dies form, which may be inserted into an annular die holder. As a result, lateral recesses and / or elevations can be attached to the compact.

Since the drive of each transverse pressing device comprises a linear drive with a fixed part fixed to the frame of the transverse pressing device and a part displaceable linearly with respect to the fixed part, which linearly displaceable part is connected to a first wedge, the wedge surface of which acts on the wedge surface of a second wedge can be displaced substantially perpendicular to the first wedge in the transverse pressing direction, can optimally on the cross press die during the pressing process acting force can be absorbed without the linear drive would be heavily stressed.

In an advantageous manner, the first wedge and the second wedge are displaceable along linear guideways attached to the frame of the transverse pressing device, whereby the occurring forces acting on the transverse ram are largely absorbed by the frame.

A further advantageous embodiment of the invention is that the pressing position of the cross press ram can be fixed by an adjustable stop, whereby the pressing position of the cross press ram is always reached very accurately regardless of further influences.

Advantageously, the stop is formed of a transverse to the direction of displacement of the first wedge adjustable third wedge, which is guided in the frame and whose wedge surface cooperates with a further wedge surface of the first wedge. As a result, on the one hand to achieve a very fine and exact adjustment, on the other hand, the stop is very stable and virtually no deformations subject.

Advantageously, the position of the cross press ram with respect to the die assembly via measuring means can be detected and transmitted to the control unit, whereby the position of the transverse ram is monitored and the adjustment of the pressing position of the cross press ram over the stop is easily possible.

A further advantageous embodiment of the invention is that each cross-pressing punch is held via a coupling device in the respective transverse pressing device. As a result, the transverse pressing dies can be exchanged in a simple manner, while the transverse pressing device can be used for virtually all compacts to be pressed having different shapes.

A further advantageous embodiment of the invention is that each transverse pressing device is equipped with a protruding bolt and that the plate is provided with a plurality of holes, which bolt protrudes in the mounted on the plate state of Querpressvorrichtung in one of the holes, and that a plurality Querpressvorrichtungen on the Plate can be fastened in different position. As a result, the transverse pressing devices can be used in predetermined positions for specific die arrangements without having to carry out large orientations of the transverse pressing devices.

Advantageously, the holes in the plate corresponding threaded holes are assigned, in which clamping screws are screwed, which are held in corresponding recesses in the context of each transverse pressing device. As a result, the transverse pressing devices in the corresponding positions on the plate can be fastened in a simple manner.

Advantageously, the recesses for receiving the clamping screws in the transverse pressing device are slot-shaped, so that the patch on the plate transverse pressing device each slightly pivoted about the bolt and thus can be aligned with respect to the die, after which the cross pressing device on the plate on the clamping screws can be fixed.

An embodiment of the invention will be explained in more detail by way of example with reference to the accompanying drawings.

• Fig. 1 in räumlicher Darstellung eine untere Stempelanordnung mit einer Matrizenanordnung mit Platte und drei auf dieser Platte befestigte Querpressvorrichtungen;
• Fig. 2 eine Draufsicht auf die Matrizenanordnung mit der Platte und den darauf befestigten Querpressvorrichtungen gemäss Fig. 1;
• Fig. 3 in räumlicher Darstellung eine Querpressvorrichtung ohne Querpressstempel, in Pressposition;
• Fig. 4 in räumlicher Darstellung eine Ansicht der Querpressvorrichtung gemäss Fig. 3 mit abgenommener Abdeckplatte;
• Fig. 5 eine Draufsicht auf die Querpressvorrichtung gemäss Fig. 3, zum Teil geschnitten;
• Fig. 6 eine Schnittdarstellung der Querpressvorrichtung entlang Linie VI-VI gemäss Fig. 7;
• Fig. 7 eine Schnittdarstellung der Querpressvorrichtung entlang Linie VII-VII gemäss Fig. 6;
• Fig. 8 eine räumliche Darstellung der Querpressvorrichtung in der zurückgezogenen Position;
• Fig. 9 in räumlicher Darstellung eine Ansicht der Querpressvorrichtung gemäss Fig. 8 mit abgenommener Abdeckplatte;
• Fig. 10 eine Draufsicht auf die Querpressvorrichtung gemäss Fig. 8, zum Teil geschnitten;
• Fig. 11 eine Schnittdarstellung der Querpressvorrichtung entlang Linie XI-XI gemäss Fig. 12;
• Fig. 12 eine Schnittdarstellung der Querpressvorrichtung entlang Linie XII-XII gemäss Fig. 11; und
• Fig. 13 eine räumliche Darstellung der Querpressvorrichtung gemäss Fig. 3 mit zusätzlich entferntem zweiten Keil.

It shows

• Fig. 1 in a spatial representation of a lower punch assembly with a die assembly with plate and three mounted on this plate cross pressing devices;
• Fig. 2 a plan view of the die assembly with the plate and the transverse pressing devices mounted thereon Fig. 1 ;
• Fig. 3 in a spatial representation of a cross-pressing device without cross-press, in pressing position;
• Fig. 4 in a spatial representation of a view of the transverse pressing device according to Fig. 3 with removed cover plate;
• Fig. 5 a plan view of the transverse pressing device according to Fig. 3 , partly cut;
• Fig. 6 a sectional view of the transverse pressing device along line VI-VI according to Fig. 7 ;
• Fig. 7 a sectional view of the transverse pressing device along line VII-VII according to Fig. 6 ;
• Fig. 8 a perspective view of the transverse pressing device in the retracted position;
• Fig. 9 in a spatial representation of a view of the transverse pressing device according to Fig. 8 with removed cover plate;
• Fig. 10 a plan view of the transverse pressing device according to Fig. 8 , partly cut;
• Fig. 11 a sectional view of the transverse pressing device along line XI-XI according to Fig. 12 ;
• Fig. 12 a sectional view of the transverse pressing device along line XII-XII according to Fig. 11 ; and
• Fig. 13 a spatial representation of the transverse pressing device according to Fig. 3 with additionally removed second wedge.

Out Fig. 1 is shown in a schematic representation of the lower punch assembly 1, which is designed as an adapter and can be used in a known manner in the lower part of a powder press, not shown. On this lower punch assembly 1, a plate 2 is placed, on which a die assembly 3 is attached. On this plate 2 are transverse pressing devices 4 can be fastened, which are each equipped with a Querpressstempel 5, which are linearly driven by a drive, which will be described in detail later. These transverse punches 5 are guided through openings 6 in the die 7 of the die assembly 3, they open in the mold cavity 8, which is formed in the die assembly 3, and in which the metal powder is fillable and is formed during the pressing process in a known manner to the corresponding compact.

At the in Fig. 1 illustrated embodiment of the device two transverse press devices 4 are arranged on the plate 2, of course, depending on the type of compact, which is to be produced, and the correspondingly formed die, for example, two to six transverse pressing devices are arranged.

Above the die assembly 3 and the transverse pressing devices 4, a Füllschuhplatte is placed in a known manner, not shown, including on the plate 2 columns 9 are mounted on which Füllschuhplatte in a known manner the filling shoe is slidably mounted, with which the mold cavity 8 are filled with metal powder can.

As will be seen in more detail later, the drives of the transverse pressing devices each have a hydraulic cylinder, to supply these hydraulic cylinders hydraulic lines 10 are attached, which are connected in a known, not shown manner with the hydraulic system of the powder press and their valves in a known manner via a control unit the powder press can be controlled.

Out Fig. 2 the arrangement of three transverse pressing devices 4 on the plate 2 is shown. The transverse compression punches 5 of these transverse pressing devices 4 protrude into the die 7, the die 7 is divided in the present embodiment, the individual parts of this die 7 are inserted into a die ring 11, through the divisions of the die 7 are the corresponding openings 6 for the cross press die. 5 educated.

The plate 2 is provided with a plurality of bores 12, these bores 12 serve to receive a bolt 13 (FIG. Fig. 7 ) which is attached to each transverse pressing device 4 and protruding at the bottom, whereby the transverse pressing devices 4 can be positioned on the plate 2. Each of these holes 12 are associated with two threaded holes 14, which are embedded in the plate 2, and in which clamping screws 15th can be screwed, with which the transverse pressing devices 4 can be mounted on the plate 2. For these clamping screws 15 4 recesses 16 are mounted in the transverse pressing devices, which are slit-shaped, so that each transverse pressing device 4 to the bolt 13 (Fig. Fig. 7 ) in the bore 12 is slightly pivotable and can be screwed in the appropriate position on the clamping screws, the Querpressstempel 5 must therefore not be aligned exactly in the center of the die 7, but may deviate from the center, as in the die 7 of the embodiment according to Fig. 2 is apparent. With this die 7, compacts 17 are produced, which have the shape of indexable inserts.

Fig. 3 shows a cross-pressing device 4. This transverse pressing device 4 comprises a frame 18, in which the drive, which is designed as a linear drive, is held, as will be described in detail later. Via this linear drive, a first wedge 19 is displaceable in one direction, represented by the double arrow 20. This first wedge 19 is guided along a linear guide track 21, which is aligned parallel to the displacement direction, represented by the double arrow 20. This linear guide track 21 is attached to the cover plate 25, which is screwed onto the frame 18.

On the wedge surface 22 of the first wedge 19 is a wedge surface 23 of a second wedge 24 at. This second wedge 24 is also linearly displaceable, in the direction which is aligned at right angles to the direction of displacement of the first wedge 19, represented by the double arrow 20, which direction is represented by a double arrow 26. The direction represented by the double arrow 26 also corresponds to the transverse pressing direction, with which the cross-pressing punch 5, not shown, (FIG. Fig. 1 and 2 ) is displaceable. By moving the first wedge 19 along the linear guide track 21 thus the second wedge 24 moves in the direction of the double arrow 26, guided by the likewise mounted in the cover plate 25 linear guides 27. On the wedge surface 23 opposite side of the second wedge 24 is a coupling device 28 attached, with Which of the transverse press dies 5, not shown, ( Fig. 1 and 2 ), these transversal punches are easily interchangeable.

Fig. 4 shows the transverse press 4 according Fig. 3 , wherein here the cover plate 25 is omitted. In this illustration it can be seen that the first wedge 19 cooperates with a third wedge 29, wherein the first wedge 19 is provided with a further wedge surface 30, which comes to rest with the wedge surface 31 of the third wedge 29. This third wedge 29 serves as a stop for the first wedge 19, this stop being adjustable, as will be seen later.

Fig. 5 shows the frame 18 of the cross-pressing device 4, with the arrangement of the first wedge 19, the second wedge 24 and the third wedge 29. The third wedge 29 is provided with a web 32 which is shown in the frame 18 transversely to the direction of displacement of the first wedge 19 held by the double arrow 20, slidably guided. In the frame 18 and in the cover plate 25 is provided with a threaded bore 33, into which a screw 34 is screwed. By turning this screw 34, the wedge 29 moves transversely to the direction of displacement of the first wedge 19, whereby the position of the first wedge 19 in Fig. 5 can be set down. This position also corresponds to the fully extended position of the second wedge 24 and consequently of the transverse punch 5 (FIG. Fig. 1 and 2 ). In this position, the transverse punch is in the pressing position. As a result, the position of the transverse press ram in the press position can be positioned very accurately by displacing the third wedge 29. The position of the second wedge 24 and consequently of the transverse pressing ram 5 is scanned in a known manner by means of measuring means 35 mounted on the frame 18 of the transverse pressing device 4, the corresponding signal being forwarded to the machine control in a known manner.

Fig. 6 shows the drive 36, with which the first wedge 19, the second wedge 24 and thus the cross press die 5 are displaceable. This drive 36 comprises a arranged in the frame 18 of the transverse pressing device 4 hydraulic cylinder 37, in which a piston 38 is slidably mounted with a piston rod 39 attached thereto. About appropriate Actuation of the piston 38, this is pushed forward or back in the hydraulic cylinder 37. In Fig. 6 are also still the recesses 16 can be seen, which are slit-shaped, in which the clamping screws 15 are screwed, with which the transverse pressing device 4 can be fastened.

Fig. 7 again shows the drive 36, which is arranged in the frame 18 of the transverse pressing device 14. On the piston 38 facing away from the end portion of the piston rod 39, a bracket 40 is fixed, which is connected to the first wedge 19. Thus, by moving the piston 38 in the hydraulic cylinder 37, the first wedge 19 can be displaced, the press position as shown in FIG Fig. 7 Incidentally, as shown in all the preceding figures, it is determined by the third wedge 29.

Also in Fig. 7 it can be seen the bolt 13, by means of which the transverse pressing device 4 on the plate 2 ( Fig. 1 and 2 ) is positioned.

Fig. 8 shows the cross-pressing device 4, accordingly Fig. 3 but with the second wedge 24, and thus the cross press die, not shown, in the retracted position. The first wedge 19 is therefore also retracted, that is, the further wedge surface 30 of the first wedge 19 is spaced from the wedge surface 31 of the third wedge 29.

Fig. 9 shows the cross-pressing device 4 in the in Fig. 8 shown position, in which case the cover plate 25 has been omitted.

Fig. 10 shows the cross-pressing device 4 in the corresponding position according to Fig. 8 and Fig. 9 ,

The same position in which the cross punch is retracted is in FIG Fig. 11 shown. The piston 38 is in the retracted position in the hydraulic cylinder 37. Accordingly, the piston rod 39 and the bracket 40 attached thereto are also in the retracted position.

The same representation as in Fig. 11 is also in Fig. 12 seen, the piston 38 is in the retracted position.

In the illustration according to Fig. 13 is the first wedge 19 can be seen, which is equipped with a step 41 on which gradation 41 bolts 42 are arranged. The second wedge 24, the in Fig. 13 is not shown, is provided with one of the gradation 21 corresponding recess, in this recess a groove is recessed into which the bolts 42 protrude. By this configuration, the second wedge 24 is coupled to the first wedge 19, when retracting the first wedge 19 and retracting the cross press die from the die, the second wedge 24 is forcibly also retracted via this connection.

As in particular from Fig. 3 it can be seen in which the press ram is in the pressing position and must absorb the pressing force acting on the front surface of the press ram when pressing a compact, this recorded pressing force is transmitted in the axial direction to the second wedge 24, from where this on the wedge surface of the second Wedge 24 is transmitted to the corresponding wedge surface 22 of the first wedge 19. The axially acting force component is transmitted through the first wedge 19 onto the linear guide track 21 of the frame 18. The resulting by the inclination of the wedge surfaces 22 and 23 component acting in the direction of the double arrow 20 is relatively small due to the relatively small angle of inclination of these two wedge surfaces 22 and 23 and the resulting friction, so that the force acting on the drive 36 residual force is very small is and can be taken over by the drive easily.

With this embodiment according to the invention, a powder press can be equipped with a plurality of transverse pressing devices, which can be positioned and fastened on the corresponding plate in a very variable number of ways. This gives a wide variety of producible on this powder pressings, a conversion is in each case in a simple manner feasible.

Claims (9)

1. Powder press for the production of a metal powder compact (17), with an upper punch arrangement, a lower punch arrangement (1) and a die arrangement (3) which forms the mould cavity (8) into which the metal powder is fillable, and afterwards, to form the compact (17), the upper punch arrangement and the lower punch arrangement (1) are able to be pressed toward each other in pressing direction, controlled by a control unit, and the lower punch arrangement (1) is equipped with a plate (2) on which the die arrangement (3) is fastened and to which plate (3) <sic. (2)> cross pressing devices (4) are fastened, which are each equipped with a cross pressing punch (5) which is linearly drivable by a drive unit (36), and which is able to be pressed in cross pressing direction substantially transversely to the pressing direction into a press position into the mould cavity (8) through an opening (6) in the die (7) and is able to be retracted out of this position, characterised in that the drive unit (36) of each cross pressing device (4) comprises a linear drive unit (37, 38) with a fixed part (37) fastened to the frame (18) of the cross pressing device (4) and a part (38) linearly movable relative to the fixed part (37), which linearly movable part (38) is connected to a first wedge (19) whose wedge surface (22) acts on the wedge surface (23) of a second wedge (24) which is movable substantially perpendicularly to the first wedge (19) in the direction of cross pressing.
2. Powder press according to claim 1, characterised in that the first wedge (19) and the second wedge (24) are movable along linear guide tracks (21; 27) fastened to the frame (18) of the cross pressing device (4).
3. Powder press according to one of the claims 1 or 2, characterised in that the pressing position of the cross pressing punch (5) is able to be set by an adjustable end stop (29).
4. Powder press according to claim 3, characterised in that the stop is formed by a third wedge (29) adjustable transversely to the direction of movement of the first wedge (19), which third wedge is guided in the frame (18) and whose wedge surface (31) co-operates with a further wedge surface (30) of the first wedge (19).
5. Powder press according to one of the claims 1 to 4, characterised in that the position of the cross pressing punch (5) in relation to the die arrangement (3) is able to be determined by measuring means (35) and is able to be transmitted to the control unit.
6. Powder press according to one of the claims 1 to 5, characterised in that each cross pressing punch (5) is held in the respective cross pressing device (4) by means of a coupling device (28).
7. Powder press according to one of the claims 1 to 6, characterised in that each cross pressing device (4) is equipped with a protruding bolt (13), and in that the plate (2) is provided with a plurality of holes (12), said bolts (13) protruding into one of the holes (12) in the state of the cross pressing device (4) being placed on the plate (2), and in that a plurality of cross pressing devices (4) are able to be fastened on the plate (2) in different positions.
8. Powder press according to claim 7, characterised in that assigned to the holes (12) in the plate (2) are corresponding threaded holes (14) into which clamping screws (15) are able to be screwed, which are held in corresponding cut-outs (16) in the frame (18) of each cross pressing device (4).
9. Powder press according to claim 8, characterised in that the cut-outs (16) are designed slot-shaped.

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