EP1362652B1 - Flow-turning method and device for forming a hub without cutting - Google Patents

Description

The invention relates on the one hand to a method for non-cutting Forming a hub on a workpiece in which a Roll with an acute-angled separating edge to one Rotation axis rotating workpiece and a material area is branched approximately V-shaped, this Subsequent material area by at least one post-forming roller is finally formed into the hub. The invention relates on the other hand, a press-rolling machine for forming a hub with at least one roller with an acute-angled separating edge and with a chuck for picking up and holding of the workpiece, the chuck relative to the roll is driven to rotate.

A generic state of the art goes for example from DE 975 677, DE 196 03 773 A1 or DE 41 15 423 A1. In these known methods, a Roll with an acute-angled separating edge, which also as Split or cutting roller is called on a flat Ronde a material area branched in a V-shaped cross section or split off. Due to the acute-angled separating edge, which essentially leads to tensile forces in the material, the roller can penetrate the workpiece relatively easily, so that even small forming forces to deliver the Nip rolls are necessary. Due to the low forming forces the material structure of both the remaining radial workpiece area as well as the branched Workpiece area not too heavily loaded. In particular the risk of microstructure formation within the workpiece structure remains low. This is especially true if one Delivery of the split roll according to the teaching of DE 41 15 423 A1 from the outer edge without an axial indentation into the workpiece only radially. Indeed a relatively long branch of material can form, whose material is not completely used to form the hub can be used.

A method and a press rolling machine for manufacturing Brake shoes are known from WO 01/66 278 A1. A round blank is split on its outer circumference and curved on both sides folded. As with the previously described procedures the final shaping is carried out using post-forming rollers.

For chipless shaping of a hub it is from DE 44 44 526 C1 also known, on a side surface of a sheet metal plate a spinning roller with a relatively large spinning radius to deliver, by which primarily in the workpiece material Compressive or compressive forces are generated. To train the The material is pressed into a receiving space. The The receiving space is formed around a central tool pin and limited by a stop on a line manager. In Depending on the size of this recording space, the Wall thickness of the hub to be molded can be determined. In these known methods, however, there are relatively high axial ones and exert radial forming forces on the workpiece. Correspondingly complex machines are to be provided, whereby the problem is that if the Material can tear off the hub to be molded.

A process that is more gentle on the workpiece is from the Known from DE 198 49 981 A1 or DE 101 21 546 A1 which by means of a special forming roller a hub is formed without cutting. The special forming roll includes a separating edge and an immediately adjacent one Compression area, the outer profile of which is the outer peripheral contour is adapted to the hub to be molded.

The invention has for its object to provide a method and a flow-forming machine, which is provided with a hub structure particularly friendly and economical conformable with high design freedom.

The task is accomplished by methods with the features of the claim 1 as well as by a pressure rolling machine with the Features of claim 11 solved. Preferred versions the invention are specified in the respective dependent claims.

The method according to the invention is characterized in that that the postforming roller has an axial stop surface, through which an axial extension of the V-shaped branched material area is limited. With the invention The process first becomes a material area by means of a roller with an acute-angled separating edge branched off, due to the acute-angled contour of Roll only low forming forces have to be applied. Due to the special contour of the roll, the forming forces introduced into the workpiece in a very targeted manner become. This protects the workpiece structure. The Risk of overstressing the structure and the The occurrence of structural cracks is significantly reduced. At the same time, there is also a high degree of design freedom and excellent material utilization take place because through the post-forming roller the V-shaped branched material area is limited in its axial extent. With the postforming roll is thus even a thickening of the branched Material area for forming the hub possible.

Another advantage of the invention is that the Roll with the acute-angled separating edge from a special high-strength tool steel or another particularly wear-resistant material can be manufactured. by virtue of the simple design can do this role despite the expensive and basically difficult to process material inexpensively are manufactured. Because the role on the actual Shape of the hub to be molded has no significant influence has the acute-angled roller for a variety of hub shapes can be used. A reworking of the Rolling, for example by grinding, is easily possible without that this affects the contour of the hub to be molded would be.

The postforming roller can because of the different stress be made from a simpler material. Consequently can be an inexpensive adjustment to the process changed hub shapes easily. An entry radius any choice can be made on the postforming roller. As a result, a foot radius on the hub can be chosen as desired become.

It is particularly economical if the axial stop surface of the postforming roller on a recess is formed, through which an outer contour and an axial length of the hub to be molded is specified. The recess can be a convex or concave or have another profile, such as steps, grooves, etc. which is in a corresponding manner on the outer contour of the depicts the hub to be molded.

It is particularly gentle on the structure of the material, if the roll with the acute-angled separating edge of one Starting position on the workpiece to an end position is delivered, on which the hub on the workpiece axially projects. The roll with the acute-angled separating edge is fed to the bottom of the hub. The postforming roll In this case, it only needs to be pushed to the edge of the foot area.

Depending on the desired shape of the hub, you can initially the infeed of the roll with the acute-angled separating edge take place, the delivery of the postforming roll only after Completion of the formation of the V-shaped branched area he follows. For a particularly short processing time it is advantageous that the post-forming roller on the V-shaped branched material area is delivered even before the roller with the acute-angled separating edge its end position has reached. In this version, delivery takes place the postforming roll for a certain period of time offset, so that by the re-forming the split off or Branch of the V-shaped material area is not hindered becomes.

Another advantageous embodiment of the method consists in that the hub between the re-forming roller and a tool mandrel is formed. The outer contour of the tool mandrel can be cylindrical or with a convex or concave profile, for example with teeth or circumferential grooves be provided.

The workpiece can be attached to the chuck in any way held along its circumference or at the edge his. According to the invention, however, it is preferred that Workpiece is held in its central area. The holding can be done by a so-called counter-holder, which centered in the workpiece and its outer area at the same time forms the tool mandrel.

A flat sheet blank or a other preform made of sheet metal or cast material. To form the hub, the roller is usually on one essentially radially extending workpiece area delivered. However, it is for special workpiece shapes also advantageous that the roller with the acute-angled Separating edge is fed radially and axially at the same time becomes. For example, a workpiece area with a wall thickness changing in the radial direction.

Another advantageous embodiment of the method according to the invention for non-cutting molding A hub is characterized in that a radial outer workpiece area axially into a recess of a Spinning chuck is pressed so that a radially inner The workpiece area protrudes axially by a defined amount, that on the protruding inner workpiece area a role is delivered, through which a wall thickness of the inner workpiece area is reduced, and that workpiece material is formed into the hub. This method according to the invention can then be used come when not molding the whole of a hub Material of a sheet metal blank or a radial workpiece area is required for material acceptance. An axial Pressing in the roll with a considerable local stress of the workpiece structure, as required in the prior art is avoided by that a defined outer workpiece area by one Partial amount of the wall thickness is set back axially. To this This creates a protruding inner workpiece area, on the outer edge of a forming roller in a simple manner can be delivered.

This method can be used in particular with a roll with an acute-angled separating edge and the subsequent delivery of a postforming roll in accordance with the previously described Procedures are used. The radial inner, protruding workpiece area can also be used another known forming roll for non-cutting shaping a hub can be reduced in its workpiece thickness.

It is advantageous that the above inner Workpiece area reduced in its wall thickness by the amount by which this axially compared to the pressed protrudes the outer workpiece area. After forming the hub is created despite the partial reduction in wall thickness a practically flat workpiece surface.

With this method, any holder of the Workpiece on the chuck. A preferred one Possibility is that the Pressing the outer workpiece area expands it radially and against an annular shoulder on the spinning chuck shaped and clamped. The workpiece would, so to speak non-positively and / or positively pressed into a ring shape will be, after the completion of the processing Workpiece ejected by an ejector on the chuck becomes.

With regard to the pressure rolling machine, the invention is characterized in that in addition a post-forming roll is provided with an axial stop surface and that the postforming roll is spatially and temporally offset from the roll is adjustable with the acute-angled separating edge. With Such a pressure rolling machine can be the inventive Carry out procedures so that the above Advantages in the pressure rolling machine according to the invention result accordingly.

Fig. 1

eine erste Ausführungsform des erfindungsgemäßen Verfahrens in drei unterschiedlichen Verahrensstadien in einer stark schematisierten Teilquerschnittsansicht;

Fig. 2

eine schematische Anordnung der Umformrollen bei dem erfindungsgemäßen Verfahren;

Fig. 3

eine weitere Ausführungsform eines erfindungsgemäßen Verfahrens in drei Verfahrensstadien gemäß der Ansichtsform von Fig. 1;

Fig. 4

eine weitere Ausführungsform des erfindungsgemäßen Verfahrens in drei Verfahrensstadien gemäß der Ansichtsform von Fig. 1; und

Fig. 5

ein weiteres erfindungsgemäßes Verfahren in fünf Verfahrensstadien in einer stark schematisierten Teilquerschnittsansicht.

In the following, the invention is further explained on the basis of preferred embodiments, which are shown schematically in the drawings. The drawings show:

Fig. 1

a first embodiment of the method according to the invention in three different procedural stages in a highly schematic partial cross-sectional view;

Fig. 2

a schematic arrangement of the forming rolls in the method according to the invention;

Fig. 3

a further embodiment of a method according to the invention in three process stages according to the view form of Fig. 1;

Fig. 4

a further embodiment of the method according to the invention in three process stages according to the view form of Fig. 1; and

Fig. 5

Another method according to the invention in five stages of the process in a highly schematic partial cross-sectional view.

1a, a circular-shaped workpiece 1 is on one The chuck 15 is arranged with a support surface and by means of a tool mandrel 16, which also serves as a counter-holder serves axially clamped. To the free edge of the a workpiece 1 rotating about an axis of rotation 14 Roll 10 with an acute-angled separating edge 12 radially delivered at an acute angle of attack.

According to the representation of Fig. 1b by Roll 10 reduces the wall thickness of the workpiece 1, wherein a material area 3 split off in cross section approximately V-shaped becomes. In this splitting with the roll 10 remains the workpiece structure in the branched material area 3 and especially in the reduced radial wall area 4 largely unchanged. Spatially offset and subsequent to the branched material area 3 a post-forming roller 20 with a recess 24 and an axial stop surface directed radially to the axis of rotation 14 22 delivered. The axial stop surface 22 limits the axial extension of the V-shaped branch Material area 3. By further radial delivery of the Postforming roller 20 according to FIG. 1c can thicken the material of the branched material area 3 accordingly the contour of the recess 24 take place. The final shape the hub 5 is in this embodiment between the Tool mandrel 16 and the recess 24 of the post-forming roller 20th educated.

The delivery of the roll 10 at different times and locations the post-forming roller 20 on the workpiece 1 is shown in FIG. 2 shown schematically. The roll 10 and the postforming roll 20 are mounted on a single press rolling machine, whereby whose feed axes are offset by 120 ° around the axis of rotation are arranged. On a further infeed axis 9, which is also offset by 120 °, for example a further postforming roller can be provided. This can be a calibration process or a special foot radius at the transition of the hub 5 to the radially extending area of workpiece 1.

A method alternative is shown in FIGS. 3a to 3c, in contrast to the method according to FIG. 1 the roller 10 with the acute-angled separating edge 12 is not only radially, but also axially at the workpiece 1 is delivered. In this way, the remaining radial workpiece area 4, which is oriented toward the axis of rotation 14 tapered wall thickness set. Such a wall thickness curve can be used for gear parts with a desired special flexibility may be advantageous.

The further process variant according to FIGS. 4a to 4c is also based on the previously described embodiments, in contrast to the embodiment of 1 shows the roller 10 with the acute-angled separating edge 12 not at the edge, but in a middle area of the circular workpiece 1 according to FIG. 4a.

The roll 10 is first corresponding in the cutting direction the acute-angled separating edge retracted into the workpiece 1, in order to impair the structure of the workpiece To avoid workpiece 1 as far as possible. The direction of displacement runs vertically to the axis of rotation 11 of the roller 10 and is shown schematically by an arrow in FIG. 4b. After reaching a certain axial position the further delivery of the roll 10 takes place as in the Embodiment of Fig. 1 in the radial direction, wherein subsequently the postforming roll in the manner already described 20 for final shaping of the hub 5 is delivered.

As can be clearly seen from FIG. 4c, the postforming roller can 20 of the thinned, radial workpiece area 4 be slightly spaced axially. The foot radius at the transition between the hub 5 and the radial workpiece area 4 can by the roller 10 or a separate shaping roller respectively.

In the method according to the invention, the forming forces can largely evenly on the branching off of the material area 3 through the roller 10 with the acute-angled separating edge 12 and on one or more post-forming rollers 20 for Forming and final shaping of the hub area 5 from the V-shaped branch Material area 3 can be distributed. It can therefore worked with lower overall maximum forming forces be what is gentle on both the workpiece and is the pressure rolling machine. The wear and the maintenance effort and the energy required to deliver the rolls are reduced. Because of the lower overall load of tools there is also the possibility of To increase the forming speed and thus the production time to shorten each workpiece.

Another aspect of the invention is in FIGS. 5a to 5e shown. A disc-shaped workpiece 1 is on a Pressure chuck 15 clamped by means of a tool mandrel 16, which at the same time acts as a counterhold to the center axially pressing the workpiece 1 against the chuck 15 serves. After the workpiece 1 about the axis of rotation 14 in Rotation is offset by means of a pressure roller, which is the postforming roller 20 in the present case outer workpiece area 6 in an annular recess 18 pressed in pressure chuck 15, as shown in Fig. 5b. It arises such a set back radially outer workpiece area 6 and an inner projecting workpiece area 7.

5c is on the outer edge projection 8 of the inner Workpiece area 7 a roller 10 with an acute angle Separating edge 12 is fed radially. This will inner workpiece area 7 in its wall thickness around the above Wall thickness amount decreased, becoming a V-shaped branched material area 3 forms. By spatially and temporally delivered delivery of a postforming roll 20 with a recess 24 and an axial stop surface 22 is the axial extension of the branched Material area 3 limited. By further radial This material area can deliver the postforming roller 20 thickened and finally shaped to the desired shape of the hub 5 become.

As can be seen from Fig. 5e, this method a workpiece 1 with a hub 5 and an outer Workpiece area 6 created with a wall thickening, wherein however, the machined face is flat.

Sufficient material is thus on the outer workpiece area 6 available, which if necessary for another non-cutting or machining to a desired Gear part can serve.

Claims (11)

1. Method for forming a hub (5) without cutting on a workpiece (1), in which a roller (10) with an acute-angled separating edge (12) is fed to the workpiece (1) that rotates about an axis of rotation (14) and a material portion (3) is split off in an approximately V-shaped manner, said material portion (3) being subsequently finished to the hub (5) by at least one contour roller (20),
   characterized in that
   the contour roller (20) has an axial stop face (22), through which an axial extension of the material portion (3) that is split off in a V-shaped manner is limited.
2. Method according to claim 1,
   characterized in that
   the axial stop face (22) of the contour roller (20) is designed on a recess (24), through which an external contour and an axial length of the hub (5) to be formed is predetermined.
3. Method according to claim 1 or 2,
   characterized in that
   the roller (10) with the acute-angled separating edge (12) is fed from a starting position at the workpiece (1) to a final position, at which the hub (5) projects axially from the workpiece (1).
4. Method according to any one of claims 1 to 3,
   characterized in that
   the contour roller (20) is fed to the material portion (3) split off in a V-shaped manner before the roller (10) with the acute-angled separating edge (12) has reached its final position.
5. Method according to any one of claims 1 to 4,
   characterized in that
   the hub (5) is formed between the contour roller (20) and a central tool mandrel (16).
6. Method according to any one of claims 1 to 5,
   characterized in that
   the workpiece (1) is supported in its centre portion.
7. Method according to any one of claims 1 to 6,
   characterized in that
   the roller (10) with the acute-angled separating edge (12) is fed radially and at same time axially.
8. Method for forming a hub without cutting according to any one of claims 1 to 7,
   characterized in that

   a radially external workpiece portion (6) is spun axially into a recess (18) of a spinning block (15) such that a radially internal workpiece portion (7) projects axially by a defined amount,

   a roller (10) is fed to the projecting internal workpiece portion (7), by means of which a wall thickness of the internal workpiece portion (7) is reduced, and

   the workpiece material arising therefrom is formed to the hub (5).
9. Method according to claim 8,
   characterized in that the projecting internal workpiece portion (7) is reduced in its wall thickness by the amount, by which said workpiece portion projects axially with respect to the spun external workpiece portion (6).
10. Method according to claim 8 or 9,
    characterized in that
    during the spinning of the external workpiece portion (6) this is extended radially and formed against an annular step on the spinning block (15) whilst being clamped thereby.
11. Flow-forming device for forming a hub according to a method in accordance with any one of claims 1 to 10,
    comprising at least a roller (10) with an acute-angled separating edge (12) for splitting off a V-shaped material portion (3) and a spinning block (15) for accommodating and supporting the workpiece (1), said spinning block being rotatably driven relative to the roller (10),
    characterized in that

    a contour roller (20) having an axial stop face (22) is additionally provided and

    in order to limit an axial extension of the V-shaped material portion (3) the contour roller (20) can be fed in a spatially and chronologically offset manner with respect to the roller (10) with the acute-angled separating edge (12) while still splitting off.

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