EP2024111B1 - Device and method for producing profiled bodies - Google Patents

Abstract

In a process to manufacture cylindrical lamella holders for an automotive clutch, the segmented sections (13) share a common external groove cut in the outer edge. During the cutting process the assembled segments move together under a single drive. Their drive operates independently of the segment rolling action against the work piece (9).

Description

The invention relates to a device and a method for producing longitudinal grooves in cylindrical workpieces, in particular for longitudinal grooves with non-uniform profile, wherein the deformation by means of segment discs, similar to a rolling process. A device according to the preamble of claim 10 is for example from the DE-A-2 065 191 known.

State of the art

In the manufacture of profile bodies, such as disc carriers of clutches, toothed belt pulleys or similar workpieces with a cylindrical basic structure, high accuracies and precision are often required. In particular, accuracy and surface quality are important.

In the DE 20 17 709 a method is described, which is used for the production of the above-mentioned components. A special rolling tool makes it possible to produce the workpiece from a blank having a smooth outer contour by means of a press, wherein each press stroke forms a workpiece from a blank. With each press stroke, a rolling process takes place in which the profile rollers press the desired outer profile into the lateral surface of the workpiece. The profile rollers are arranged in a lower tool along the circumference of the workpiece to be machined. If the workpiece is pressed between the rollers by means of an upper tool fastened to the plunger of the press, these are supported on support rollers with appropriate mounting. The lower tool can be constructed rotationally symmetrical, wherein the profile of the workpiece generating individual profile rollers are regularly distributed at a uniform angle to each other along the circumference of the workpiece. As a result, and as a result of the resulting rotationally symmetric distribution of forces during a forming process, the individual grooves produced by the respective profile rollers are virtually identical to one another. In particular, a paragraph-free outer contour is achieved.

The disadvantage of this method is that the rotation and thus the rolling of the profile rollers is only generated by the forces acting during the forming forces between the workpiece and profile roller. This creates a non-definable slip of the profile roller relative to the workpiece. For continuous, longitudinally uniform profiles of this slip usually does not cause problems. However, if the profile is irregular in the longitudinal direction, for example, with a web running transversely to the longitudinal groove in the middle of the profile length, the slip leads to dimensional inaccuracies and thus to quality defects.

In the DE 195 06 391 A1 discloses a method in which the profile rollers are driven such that the circumferential speed in the forming area coincides with the speed of the workpiece. The drive is made by transmitting the plunger movement via gear means, such as racks and gears on the profile rollers. Because of this Method or by the arrangement of the above-mentioned transmission means the slip between the profile rollers and workpiece is reliably avoided.

The disadvantage of this method is the very complicated structural design and the resulting high cost of the device. Another disadvantage is that a large overall height of the device is required by the plurality of transmission means.

In the EP 0 006 137 A1 is also described an apparatus for producing longitudinal grooves in a cylindrical workpiece. In this solution, the forming is done not by profile rolls but by segment discs. The segment discs are not driven. The outer contours of the segment discs roll on the surface of the moving down workpiece. As a result, the segment discs move on a circular trajectory. The positions of the segment discs at the beginning of the procedure are defined by spring-actuated retaining pins. The segment discs are connected by means of a spherical plain bearing with a housing. Due to the fact that the segmented disks are moved exclusively by the forces acting during the deformation and have no drive synchronized with the tappet movement, a slight slip between the segmented disk surface and the workpiece can not be avoided. In addition, a precisely defined initial position of the segment discs for the forming process can not be realized. Especially for workpieces with longitudinally irregular groove profiles this is a major disadvantage.

Task and advantage of the invention

The invention has for its object to provide a method and an apparatus for producing profiles in cylindrical workpieces, by means of a structurally simple and thus cost-effective and reliable tool, with a slip between the workpiece surface and the Umformwerkzeugelementen is safely avoided, and by a precisely defined starting point of the Umformeingriffes a high precision of the profile to be produced is achieved.

This object is achieved by a method having the features of claim 1 and starting from a device according to the preamble of claim 10, by the characterizing features of claim 10.

In the dependent claims advantageous and expedient developments of the method according to the invention or the device according to the invention are given.

The invention is based on the idea to perform the forming process similar to a Rollumformverfahren, but not with profile rollers as Umformwerkzeugelement, but with driven segment discs. The segment discs are guided on sliding surfaces and are synchronized by a positive coupling with the punch or tool lower part with the movement of the workpiece., This means that the segment discs are not moved by the forces acting during the forming forces, but by the movement of the punch. This eliminates slippage between the segment discs and the workpiece during forming. As already mentioned, the Segment discs guided on sliding surfaces. These sliding surfaces are curved such that a rolling of the profiled segment disc surfaces on the workpiece is made possible. Thus, the segment discs can move along the curved sliding surfaces, these are held and guided from below through the lower tool part and from above through the upper tool or the die. The holding force on the segment discs is applied by upper gas springs, which in turn are connected to the upper tool.

The segment discs are held at any time during the forming between a driver attached to the tool top and the lower tool part and thus perform exactly the same vertical movement as the workpiece, which is also connected to the upper tool or with attached components. The contact surfaces of the components, which are in communication with the segment discs, are designed so that the horizontal portion of the segment disc movement is absorbed. Preferably, the surfaces are configured to allow for substantially horizontal sliding movement between the segment discs and the contacting components. This device described, represents a structurally simple and therefore also robust and cost-effective, but also a very precise and high-quality solution.

Another advantage of the method and the device according to the invention is the possibility to lift the workpiece out of the device after the forming and to release it for a workpiece transport system. This lifting takes place by means of a lower gas spring.

Another feature of the method and the device according to the invention is that the tool lower part is displaced during the forming process through the upper tool over the punch, the rolling mandrel and the workpiece down against a force. This force opposing the forming movement can for example result from the lifting mechanism.

Further details and advantages of the invention will become apparent from the embodiment illustrated by the figures.

Figur 1

Vorrichtung nach dem Einlegen eines Rohlings

Figur 2

Vorrichtung bei Umformbeginn

Figur 3

Vorrichtung bei Umformende

Figur 4

Vorrichtung nach Ausheben des Werkstückes

Figur 5

Vergrößerte Darstellung des Umformeingriffes während der Umformung

Show it:

FIG. 1

Device after inserting a blank

FIG. 2

Device at the beginning of forming

FIG. 3

Device at the end of forming

FIG. 4

Device after lifting the workpiece

FIG. 5

Enlarged view of forming operation during forming

Description of an embodiment

FIG. 1 shows the device 1 according to the invention in a sectional view. The device 1 consists of an upper tool part 2 and a lower tool part 3. The upper part of the tool 4 is connected to the punch 5 with the rolling mandrel 5. The lower tool part 3 is in a cast housing 6 vertically movably mounted. Via a lower gas spring 7, the lower tool part 3 is connected to a workpiece holder 8. In the illustrated position, the workpiece 9 has already been stored on the workpiece holder 8 as a blank by the grippers 10 of a workpiece transport system, not shown here. The punch 4 with the rolling mandrel 5 is in the upper reversal point. Now begins the forming process, the punch 4 moves with the rolling mandrel 5 down, while the workpiece 9 also performs a downward vertical movement. The movement of the workpiece 9 is generated in that the workpiece holder 8 is displaced with the workpiece 9 against the force of the lower gas spring 7 down.

In FIG. 2 the device 1 has reached a position in which a driver 11, which is connected via upper gas springs 12 with the upper tool part 2, has reached the upper contact surfaces of the segment discs 13. The lower contact surfaces of the segment discs 13 rest on the lower tool part 3. The fact that the driver 11 rests on the segment discs 13, drive the upper gas springs 12 in a continuation of the downward movement of the punch 4 with the rolling mandrel 5 and the tool shell 2, as far as the position is reached in FIG. 3 is shown. The upper gas springs 12 are now retracted, the rolling mandrel 5 is located in the workpiece 9 and the segment discs 13 are held from above by the driver 11 and from below through the lower tool part 3 in a well-defined position. Starting from this position in a further downward movement of the punch 4, the deformation of the workpiece 9 begins by the segment discs thirteenth

Due to the positive connections of all moving components, the segment discs 13, based on their vertical component movement, moved synchronously with the workpiece 9 down. The necessary for the forming process rolling of the segment discs 13 on the workpiece 9 is achieved in that the segment discs 13 move on a curved sliding surface 14 along. Through this sliding guide and the vertical drive by the driver 11 and by the lower tool part 3, the segment discs 13 move on a circular path and can roll on the workpiece 3 exactly. The workpiece 9 facing sides of the segment discs 13 are equipped with the negative shape of the workpiece 9 to be produced profile. In this embodiment, it is a profile with longitudinal grooves, which have a web 15 in the middle of the profile. In FIG. 5 this profile is clearly visible. In the position shown, the forming has already taken place. In the middle of the profile of the web 15 is clearly visible. The shape and in particular the position of this web 15 high quality requirements are made. A precise deformation is only possible if, as in the device 1 according to the invention, a precisely defined starting position for the deformation is present, which is independent of friction conditions between segment discs 13 and the workpiece 9 or thickness tolerances of the workpiece 9.

FIG. 4 shows the position of the device 1 after the forming process. The segment discs 13 have been pressed by the contact with the driver 11 down and have rolled so the profile on the workpiece 9. The sliding movement of the segment discs 13 on the sliding surfaces 14 is made possible or supported by a pressure lubrication, which over the Lubrication channel 16 is carried out. Due to the circular movement of the segment discs 13 along the sliding surfaces 14 arise at the contact points between the driver 11 and the segment discs 13 and between the lower tool part 3 and the segment discs 13, relative movements. The contact surfaces of the driver 11 and the lower tool part 3 are therefore designed so that the segment discs 13 are held or guided at any time during the forming both from above, and from below. After the forming process is completed, the tool upper part 2 moves with the punch 4 and the rolling mandrel 5 upwards. At the same time, the lower gas spring 7 extends and moves the workpiece holder 8 with the formed workpiece 9 in the same manner as the punch 5 up until the position is reached in FIG. 1 is shown. The workpiece 9 is now free and can be gripped and transported by the grippers 10 of the workpiece transport system.

The invention is not limited to the illustrated and described embodiment. It also includes all expert training within the scope of the following claims.

LIST OF REFERENCE NUMBERS

1

contraption

2

Upper die

3

Tool part

4

stamp

5

roll Dorn

6

cast housing

7

lower gas spring

8th

Workpiece holder

9

workpiece

10

grab

11

takeaway

12

upper gas springs

13

Circles segment

14

sliding surface

15

web

16

lubrication channel

Claims (12)

1. Method for producing longitudinal grooves in cylindrical workpieces, wherein a profile is formed on the circumference of the workpiece by means of concentrically arranged profiled segment discs,

   - wherein the segment discs (13) are moved at each instant of the forming process by a drive, and said drive is independent of the rolling motion of the segment discs (13) on the workpiece (9),

   - wherein a lower die part (3) is connected via a lower gas spring (7) to a workpiece mount (8) and is mounted to be vertically mobile,

   - wherein the workpiece (9) is placed on the workpiece mount (8),

   - wherein at the start of the forming process a stamp (4), which is securely connected to an upper die part (2), moves downwards with a roller rod (5), whilst the workpiece (9) also performs a downwards vertical movement and,

   - wherein the workpiece mount (8) is displaced downwards with the workpiece (9) against the force of the lower gas spring (7),

   - wherein when the roller rod (5) is located in the workpiece (9), during a further downwards movement of the stamp (4) the forming of the workpiece (9) by the segment discs (13) begins,

   - wherein the lower die part during the forming process is displaced downwards by the upper die part over the stamp, the roller rod and the die against a force opposite the forming movement,

   - after the forming process has ended the upper die part (2) with the stamp (4) and the roller rod (5) moves upwards, at the same time the lower gas spring (7) extends and moves the workpiece mount (8) with the formed workpiece (9) upwards, wherein the workpiece is now free and can be gripped by the grippers of a workpiece transport system,

   - wherein the segment discs (13) at each instant of the forming are held from above by a driver (11) secured to the upper die part (2), which driver is connected by upper gas springs (12) to the upper die part (2), and from below by the lower die part (3) in a precisely defined position and thus perform exactly the same vertical movement as the workpiece (9), which is also connected to the upper die part (2) or with components secured onto the latter,

   - wherein the driver (11) lies on the segment discs (13) and in this way the upper gas springs (12) in a continuation of the downwards movement of the stamp (4) with the roller rod (5) or the upper die part (2) retract until the position is reached, in which the gas springs (12) are retracted and

   - wherein the segment discs (13) are pushed downwards by contact with the driver (11).
2. Method according to claim 1, characterised in that the drive of the segment discs (13) after the forming process is performed during the lifting out process via contact surfaces on the lower die part (3) or on components which are secured to the lower die part (3).
3. Method according to one of the preceding claims 1 to 2, characterised in that the profiled segments (13) are held by clamping on respectively at least two contact surfaces in a defined position, which is necessary as a start position for the forming.
4. Method according to claim 3, characterised in that the clamping is achieved by the cooperation of a downwards movement of the upper die part (2) and the upper gas springs (12) secured thereon.
5. Method according to any one of claims 1 to 4, characterised in that after the forming process the workpiece (9) is lifted out of the device (1).
6. Method according to claim 5, characterised in that the lifting out movement is performed by means of the lower gas spring (7), which during the forming process generates a counter force.
7. Method according to any one of claims 1 to 6, characterised in that the workpiece (9) is moved by the downwards movement of the upper die part (2) by means of the stamp (4) and the roller rod (5) past the segment discs (13) and in that in this way a profile is produced on the workpiece (9) according to the external contour of the segment discs (13).
8. Method according to any one of claims 1 to 7, characterised in that during the forming process the lower die part (3) is displaced downwards with the workpiece mount (8).
9. Method according to any one of claims 1 to 8, characterised in that after the forming process by means of the lower gas spring (7) and the workpiece mount (8) the workpiece (9) is lifted out of the device (1).
10. Device (1) for producing longitudinal grooves in cylindrical workpieces (9) by using a forming method, wherein a profile is produced on the circumference of the workpiece (9) by means of concentrically arranged segment discs (13), wherein the device (1) consists of an upper die part (2) and a lower die part (3), wherein the segment discs (13) are displaceably mounted on sliding surfaces (14), wherein the displacement of the segmental discs (13) is performed by contact with the moving punch (4) or with components secured to the punch (4) and by contact with the also moving lower die part (3) or with components secured to the lower die part (3), characterised in that

    - a stamp (4) and roller rod (5) are securely connected to the upper die part (2) and

    - in that a workpiece mount (8) is connected via a lower gas spring (7) to the lower die part (3), which is mounted to be movable vertically,

    - wherein the roller rod (5) is located during the forming in the workpiece (9) and

    - wherein the segment discs (13) during the forming are held from above by a driver (11) and from below by the lower die part (3) in a precisely defined position, wherein the driver (11) is connected by upper gas springs (12) to the upper die part (2), wherein the upper gas springs (12) are retracted,

    - wherein the lower die apart is displaced during the forming process by the upper die part over the stamp, the roller rod and the die downwards against a force opposite the forming movement.
11. Device according to claim 10, characterised in that on the components (11, 3) in contact with the profiled segments contact surfaces are provided, on which sliding relative movements are possible.
12. Device according to either of claims 10 and 11, characterised in that pressure lubrication is provided between the sliding surfaces (14) and the segment discs (13).

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