EP0558815A1 - Device for producing a hollow workpiece, profiled, at least internally, in a straight or oblique direction with respect to the workpiece-axis, and its use - Google Patents

Abstract

A Grob cold-rolling machine, which is known per se, can be taken as a basis, the said machine, as is known, having rolling-head carriers (26) which can be adjusted towards and away from the workpiece (1, 11, 111) and contain rolling heads (27) which can be driven in rotation. Mounted in the rolling heads (27) are impact rollers (28) which, as the rolling heads (27) revolve, revolve on a circular path (280) and can perform individual rolling operations on a workpiece situated on a mandrel (3). In addition, an undriven pressure roller (29) with the ability to rotate freely is mounted on each of the rolling-head carriers (26) outside the circular path (280) of the impact rollers (28), being mounted on a roller axis (290) parallel to or obliquely inclined with respect to the mandrel axis (31). The pressure rollers (29) can be used to perform a predominantly axial deformation, after which a predominantly radial deformation can be carried out by means of the impact rollers (28), the entire operation taking place in the same set-up and on the same mandrel (3). Economically advantageous manufacture of the workpieces can thereby be achieved (without loss of quality). In fact, an improvement in quality is possible. <IMAGE>

Description

The invention relates to a device according to the preamble of claim 1 and a method for producing a hollow workpiece that is profiled at least on the inside straight or obliquely to the workpiece axis by cold forming by means of the device according to the invention.

Workpieces can be obtained which have the profile on the inside and / or outside.

If the profiling is provided on the inside and outside, a more or less strong correspondence or, as far as possible, a wide variety of the inner and outer profile can be achieved.

As a profile, for example, a toothing comes into question, which can be designed either as a driving toothing or as a real impeller toothing.

The well-known Grob method is excellently suited for the production of high-quality profiles (for example of gears) on hollow workpieces. It should be briefly summarized below, although it is known worldwide in writing and practice:

For example, the production of an external toothing on a relatively thick-walled hollow workpiece is published in CH-PS 579 427, FR-PS 75 385 39 and DE-OS 25 49 230.

In the case of a relatively thin-walled hollow workpiece, with the rough method, the outer profile and an inner profile are simultaneously produced by cold forming, which profiles can be different. For this purpose, the tubular part of the blank is drawn onto a mandrel corresponding to the inner profile. In this state, the workpiece receives a workpiece feed, in which it is displaced along its workpiece axis and rotated about the workpiece axis. During this workpiece feed, the workpiece is machined from the outside with ring-like profiled rollers, with each roller performing abrupt single rolling operations in rapid succession coordinated with the profile division and the workpiece feed. This single rolling leads one in the same and mainly in the longitudinal direction. Single rolling operations carried out in succession with the same roller are arranged on a helical zone, the zone being determined by the workpiece feed. The individual rolling operations which follow one another in the longitudinal direction of the profile in the same tooth gap are performed so as to overlap with respect to their attack on the workpiece. In this method of cold forming on a profiled mandrel, material is conveyed along each relatively small workpiece section in a mainly radial direction into the gaps of the mandrel with each individual rolling process.

In the case of relatively thick-walled workpieces, it is also possible to produce only one inner profile on a profiled mandrel alone. If the shape of the outer surface is not very important, it can be designed as desired, more or less smoothly. You can use rollers without a profile, which you don't even have to run with precise synchronization with regard to the workpiece rotation.

According to the prior art, the pot-shaped blank hollow bodies are produced in several stages on very expensive step presses (transfer presses). Only after the last pressing stage can the blank hollow bodies be brought to the coarse machine and mounted on the mandrel on them and processed according to the coarse method.

The invention has for its object to produce hollow profiled workpieces more economically than before by the Grob method, without doing so Accept loss of product quality.

To achieve this object, the device defined in claim 1 and a method for producing a profiled hollow body by cold forming by means of the device according to the invention are proposed.

• Eine axial verschiebliche und drehbare Werkstückaufnahme mit einem profilierten Dorn, dessen Profil gerade oder schräg zur Dornachse verläuft.
• Einen in einem Walzkopfträger drehbaren Walzkopf, in welchem eine durch ihn zum planetenartigen Umlaufen mitnehmbare drehbare Schlagwalze gelagert ist, mit der bei jeder Walzkopfumdrehung ein Teilwalzvorgang an dem auf dem Dorn koaxial befindlichen Werkstückrohling durchführbar ist.

The device according to the invention has the following components for carrying out the rough method in a manner known per se:

• An axially displaceable and rotatable workpiece holder with a profiled mandrel, the profile of which is straight or oblique to the mandrel axis.
• A roller head rotatable in a roller head carrier, in which a rotatable impact roller, which can be carried by it for the planet-like rotation, is mounted, with which a partial rolling operation on the workpiece blank located coaxially on the mandrel can be carried out with each roller head revolution.

• Eine Drückrolle, welche am Walzkopfträger auf einer Rollenachse, ausserhalb des Umlaufbereichs der Schlagwalze frei drehbar gelagert ist.
• Die Rollenachse kann zur Dornachse parallel oder schräg geneigt angeordnet sein.

What is new about the device according to the invention:

• A spinning roller, which is freely rotatably mounted on the roller head carrier on a roller axis, outside the rotating area of the beater roller.
• The roller axis can be arranged parallel or obliquely inclined to the mandrel axis.

In the method according to the invention, the blank on the device according to the invention is cold formed on the same mandrel in a single clamping (ie in the same clamping) first by pressing it to the hollow hollow body and then by the rough method to the product.

Fig. 1

eine Draufsicht auf eine Vorrichtung,

Fig. 2

einen gegenüber Fig. 1 vergrösserten Ausschnitt in Draufsicht auf den Werkstückbereich vor Beginn der Kaltumformung,

Fig. 3

den Ausschnitt der Fig. 2 im Zuge des Drückens, wobei das Werkstück geschnitten dargestellt ist,

Fig. 4

den Ausschnitt der Fig. 2 nach dem Drücken und unmittelbar vor dem Schlagwalzen,

Fig. 5

den Ausschnitt der Fig. 2 im Zuge des Schlagwalzens,

Fig. 6

den Ausschnitt der Fig. 2 nach dem Ende des Schlagwalzens,

Fig. 7

einen Querschnitt durch das gedrückte Werkstück aus Fig. 4,

Fig. 8

einen Querschnitt durch das nur innen profilierte Werkstück,
und

Fig. 9

einen Querschnitt durch ein innen und aussen profiliertes Werkstück.

In der Zeichnung sind die nachstehenden Teile bezeichnet:

A

Axial-Vorschub-Richtung von 3.

D

Zu- und Wegstell-Richtung von 26.

R

Rotationsbewegungs-Richtung von 3.

W

Umlaufrichtung von 27.

Z

Werkstückachse.

1

Werkstück mit Innenverzahnung (Fig. 8).

10

Werkstück mit Innen- und Aussenverzahnung (Fig. 9).

11

Rohling-Scheibe.

111

Rohling-Hohlkörper (schon gedrückt).

2

Vorrichtung.

20

Maschinengestell.

21

Haltestempel.

22

Gegenstempel.

23

Antriebsschlitten.

24

Schraubenspindel.

25

Antrieb von 24.

26

Walzkopfträger.

27

Walzkopf.

28

Schlagwalze für 1.

280

Flugkreis von 28.

281

Schlagwalze für 10.

29

Drückrolle.

290

Rollenachse.

3

Dorn für 1.

30

Dorn für 10 (Fig. 9).

31

Dornachse (mit Z hier zusammenfallend).

32

Profil (Verzahnung) von 3.

The invention is discussed below with reference to the purely schematic drawing, for example.
Show it:

Fig. 1

a plan view of a device,

Fig. 2

FIG. 2 shows an enlarged detail from the plan view of the workpiece area before the start of cold forming,

Fig. 3

2 in the course of pressing, the workpiece being shown in section,

Fig. 4

2 after pressing and immediately before the impact rolling,

Fig. 5

2 in the course of impact rolling,

Fig. 6

2 after the end of the impact rolling,

Fig. 7

3 shows a cross section through the pressed workpiece from FIG. 4,

Fig. 8

a cross section through the workpiece which is only profiled on the inside,
and

Fig. 9

a cross section through a workpiece profiled inside and outside.

The following parts are identified in the drawing:

A

Axial feed direction from 3.

D

Entry and exit direction from 26.

R

Rotational direction of 3.

W

Orbital direction of 27.

Z

Workpiece axis.

1

Workpiece with internal toothing (Fig. 8).

10th

Workpiece with internal and external teeth (Fig. 9).

11

Blank disc.

111

Blank hollow body (already pressed).

2nd

Contraption.

20th

Machine frame.

21

Holding stamp.

22

Counter stamp.

23

Drive carriage.

24th

Screw spindle.

25th

Drive from 24.

26

Roll head carrier.

27th

Roller head.

28

Impact roller for 1.

280

Flight circle of 28.

281

Impact roller for 10.

29

Spinning roller.

290

Roller axis.

3rd

Thorn for 1.

30th

Mandrel for 10 (Fig. 9).

31

Mandrel axis (coinciding with Z here).

32

Profile (toothing) of 3.

The device 2 (FIG. 1) has in its machine frame 20 a holding punch 21 which is coaxial with the mandrel axis 31 (here also corresponds to the workpiece axis Z) and which moves from the latter in accordance with the movement of the counter-punch 22 (it also lies on the axis 31) becomes.
The disc-shaped blank 11 and the mandrel 3 are already drawn here clamped between the two stamps 21, 22.

The counter-punch 22 can be rotated by the drive slide 23 in the direction of the arrow R such that the rotational movement can be transmitted to the mandrel 3 and blank 11 or 111 or to the workpiece 1.

In addition, the drive carriage 23 can optionally be advanced axially in the direction of arrow A in the direction of rotation W by the screw spindle 24 in coordination with the rotation of the roller heads 27. The drive 25 of the screw spindle 24 can e.g. be determined by means of electronic control means (not shown).

Two opposing roller head carriers 26 are shown in the machine frame 20. The roller head supports 26 can be set in the direction of the double arrows D to the axis 31 or Z towards or away from them by means of setting stamps, not shown. As a rule, in the situation shown you set them to the correct distance and leave them there until the rolling is finished, or you adjust them during the rolling process via an NC axis in accordance with the technological requirements. For the Pushing back and ejection of the finished workpiece can be adjusted if necessary.

A roller head 27 is rotatably driven in each roller head carrier 26. The drive can take place in a manner known per se. The roller heads 27 are driven with the opposite direction of rotation W synchronously in such a way that the striking rollers 28 mounted in them act simultaneously on the workpiece 1 or on the blank 111. A synchronization to the rotational movement of the workpiece 1 or the blank 111 can also be carried out by means (not shown) of known mechanical and / or electronic means.

In each roller head 27, only one impact roller 28 is shown here. However, there could also be more rollers, which would change the drive conditions accordingly.

A pressure roller 29 is mounted on each roller head carrier on a roller axis 290 so that it can rotate freely.

Here, as shown here, the pressure rollers 29 can be dimensioned in such a way that there is no need to adjust the infeed at the end of the pressure operation in order to begin with the beating rollers.

However, one can also proceed in such a way that the delivery position is changed by moving the roller head supports 26 in the direction of the double arrows D in the course of the pressing and or afterwards. This can also be done using an NC axis.

• Man spannt einen Rohling 11 in der in Fig. 1 und 2 dargestellten Weise ein.
• Man stellt die Walzkopfträger 26 in der in den Fig. 1 und 2 dargestellten Stellung so ein, dass die Drückrollen 29 beim Vorschieben des Rohlings 11 in Richtung des Pfeiles A am Rohling 11 abwälzend angreifen. In der Fig. 3 ist etwa die mittlere Position beim Drücken dargestellt.- Beim Drücken wird das Material somit vorwiegend in Richtung der Dornachse 31, also axial umgeformt.
• An Schluss des Drückens gelangt man in die in Fig. 4 gezeigte Position, wenn der Rohling-Hohlkörper 111 auf dem Dorn 3 fertig ist.
• Während des gesamten Drückvorgangs befinden sich die Schlagwalzen 28 in der in den Fig. 1 bis 4, gezeichneten Position, so dass sie den Drückvorgang während seiner ganzen Dauer nie behindern. Diese Positionierung kann über einen als NC-Achse ausgebildeten Antrieb der Walzköpfe 27 erfolgen.
• Nun kann mit dem Schlagwalzen nach der Grob Methode begonnen werden. Dabei ist es wesentlich, dass die Drückrollen 29 ausserhalb des Flugkreises 280 der Schlagwalzen 28 liegen. Sonst kann in an sich bekannter Weise nach der Grob Methode vorgegangen werden. - Dabei wird der Werkstoff vorwiegend radial bezüglich der Dornachse 31 umgeformt.

In the method according to the invention for producing the profiled (here internally toothed) workpiece 1, the procedure is as follows:

• A blank 11 is clamped in the in FIGS. 1 and 2 shown way.
• The roller head supports 26 are set in the position shown in FIGS. 1 and 2 so that the pressure rollers 29 roll on the blank 11 when the blank 11 is being advanced in the direction of arrow A. 3 shows approximately the middle position when pressed. When pressed, the material is thus predominantly formed in the direction of the mandrel axis 31, that is to say axially.
• At the end of the pressing, the position shown in FIG. 4 is reached when the blank hollow body 111 on the mandrel 3 is finished.
• During the entire pressing process, the beater rollers 28 are in the position shown in FIGS. 1 to 4, so that they never hinder the pressing process during its entire duration. This positioning can take place via a drive of the roller heads 27 designed as an NC axis.
• Now you can start beating with the Grob method. It is essential that the pressure rollers 29 lie outside the flight circle 280 of the beater rollers 28. Otherwise, the Grob method can be used in a manner known per se. - The material is predominantly formed radially with respect to the mandrel axis 31.

The impact rolling process gradually produces the internal toothing of the workpiece 1 in the manner typical of the Grob method by gradually molding it into the profile 32 of the mandrel 3 (cf. FIG. 8).

• Aus einer Rondelle 11 mit 4,5 mm Blechstärke wird in einem ersten Arbeitsgang ein Topf 111 mit einer Wandstärke von ebenfalls 4,5 mm und einem Innendurchmesser von 170 mm gedrückt.

  - Werkstückdrehzahl mit Dorn

  20 Umdreh./Min.

  - Axialvorschub des Werkstücks mit Dorn

  50 mm/Min.

• Anschliessend wird in der gleichen Aufspannung auf den gleichen Dorn der Topf 111 nach der Grob Methode mit einer Innenverzahnung versehen.

  - Zähnezahl der Innenverzahnung

  Z = 40

  - Walzkopfdrehzahl

  1400 Undreh./Min.

  - Werkstückdrehzahl mit Dorn

  35 Umdreh./Min.

  - Werkstückvorschub mit Dorn

  300 mm/Min.

In this way you can work as follows:

• In a first operation, a pot 111 with a wall thickness of also 4.5 mm and an inner diameter of 170 mm is pressed out of a rondelle 11 with a sheet metal thickness of 4.5 mm.

  - Workpiece speed with mandrel

  20 rev / min

  - Axial feed of the workpiece with mandrel

  50 mm / min.

• The pot 111 is then provided with internal teeth in the same setting on the same mandrel according to the Grob method.

  - Number of teeth of the internal toothing

  Z = 40

  - roller head speed

  1400 rev / min

  - Workpiece speed with mandrel

  35 RPM

  - Workpiece feed with mandrel

  300 mm / min.

If the outer surface of the workpiece 1 is then processed again with the pressure rollers, the surface can be improved if necessary, so that, for example, it is not necessary to overtighten.

If the mandrel 3 is replaced by the mandrel 30 (FIG. 9) and the beater rollers 28 by the beater rollers 281 (FIG. 9) and the workpiece rotation movement is synchronized with the roller head speed, one obtains (with an otherwise unchanged device and otherwise unchanged mode of operation) the inside and outside similarly profiled workpiece 10 (FIG. 9), as is known per se in the Grob method.

It is also possible to obtain only one external profile, for example an external toothing, alone if one uses the Grob method in a manner known per se (not shown) uses a non-profiled mandrel and a profiled beater roller.

In addition, you can also get different inner and outer profiles if you use the Grob method in a known (not shown) manner different profiles on mandrel and beater.

It can be seen from what has been said that the device according to the invention and the method according to the invention enable an economically advantageous production of profiled hollow workpieces in a single clamping on a single (same) mandrel. At least the same quality is maintained as can be achieved by the Grob method according to the previous method with locally produced blank hollow bodies.

In general, however, there is an economic advantage of a higher quality consistency of the products, because they are quasi finished on the same mandrel and in the same clamping on the same machine from raw material (here blank 11) to the finished product (here workpiece 1) will.

Claims (3)

Device for producing a hollow workpiece (1; 10) which is profiled at least on the inside straight or obliquely to the workpiece axis (Z), - With a by means of drive means (21 to and 25) along a mandrel axis (31) axially (A) and about the mandrel axis (31) rotating (R) driven workpiece holder (21, 22) in which a coaxial to the mandrel axis (31) profiled Mandrel (3; 30) with a profile (32) running straight or obliquely to the mandrel axis (31) is provided - and with at least one roller head carrier (26) which is adjustable relative to the mandrel axis (31), in each of which a rotationally drivable roller head (27) is seated, in which roller head (27) at least one beater roller (28; 281) is rotatably mounted, so that by means of the impact roller (28; 281) a partial rolling process can be carried out on a workpiece preliminary product (111) located on the mandrel (3; 30) with each revolution of the roller head,
characterized in that
on the at least one roller head carrier (26) a pressure roller (29) is freely rotatable without drive on a roller axis (290) parallel or inclined to the mandrel axis (31) and is mounted outside the flight circle (280) of the at least one impact roller (28; 281). Apparatus according to claim 1, characterized in that two opposing roller head carriers (26), each with a roller head (27), are provided. Method for producing a profiled hollow workpiece (1; 10), which has a profile running at least on the inside or obliquely to the workpiece axis (Z), by cold forming by means of the device according to one of the preceding device claims,
characterized in that
a blank (11) clamped in the workpiece holder (21, 22) is pressed onto the mandrel (3; 30) by predominantly axial deformation by means of one or more pressure rollers (29) and the workpiece intermediate (111) thus obtained is clamped in the same way The mandrel (3; 30) is processed by means of at least one impact roller (28; 281) according to the rough method and the profiling is generated in the process.

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