FORMING TOOL, IN PARTICULAR A KNEADING TOOL

Abstract

The invention relates to a forming tool, in particular a kneading tool, which has a base body (12′), in which at least one forming element (21) is disposed, inclined at a first angle of inclination (α1) to a central axis (M) of the deformation tool (12), which results in the determination of an inlet chamfer (S) of the forming element (12). According to the invention, it is provided that in the surface (21′) of the forming element (21) running in an inclined manner below the first angle of inclination (α1) a recessed surface structure (22) is formed, which has at least one recess (23) with a trailing edge (23a), and that the trailing edge (23a) of said recess (23), related to the inlet chamfer (S) of the forming element (21) defined by the first angle of inclination (α1), has a second angle of inclination (α2), which is oriented towards the opposite direction with regard to the first angle of inclination (α1), and the absolute value thereof is larger than or equal to the absolute value of the first angle of inclination (α1).

Description

The invention relates to a forming tool, in particular a swaging tool, which has a base body, in which at least one forming element is provided, which is inclined at a first angle of inclination to a central axis of the forming tool, thereby determining an intake slope of the forming tool.

Such a forming tool is known from DE 103 28 052 B4 of the applicant and is used for the forming, in particular for the swaging, of work pieces in a swaging machine. During such a forming process performed by means of the known forming tools substantial axial forces acting upon the work piece are created, which is true for a feed swaging process as well as for a recess swaging process. These forces can result in a disadvantageous manner in damage symptoms on the work piece, which appear in form of bulgings or cripplings. The axial force created by the forming tools furthermore puts stress on the forming machine as well as on the feed system for the work piece and on the clamping device holding the workpiece, since the afore-mentioned units have got to compensate the axial forces generated by the forming process. In order to counteract these axial forces, DE 103 28 052 B4 discloses that on the surface of the forming element of the forming tool an elevated, relief-like and wave-like surface structure is provided, which has got a plurality of elevations. Via these elevated surface structure on the surface of the forming element a forming tool is created, which has got the advantage that the areas of the work pieces acted upon with this forming tool have got a high surface quality. A further reduction of the stress created by the axial forces during the forming process is still desired.

It is the object of the present invention to further develop a forming tool of the afore-mentioned kind, so that by means of the inventive forming tool a reduction of the axial forces is achieved.

This object is solved by the invention in that in the surface of the forming element being inclined with the first angle of inclination a recessed surface structure is formed, having at least one recess with a declining face, and that the declining face of this recess has got, in relation to the intake slope of the forming element, a second angle of inclination, which is orientated in an opposite direction with regard to the first angle of inclination and the absolute value thereof is larger than or equal to the absolute value of the first angle of inclination.

By the inventive measures it is achieved in an advantageous way that in the surface of the forming element at least one, preferably a plurality of recesses are provided, the declining face of which is declined larger than the one of the forming element and is oppositely orientated to its declination. By this it is achieved that, when radial forming forces act upon the work piece, the declining faces of the recesses assimilate the axial force component, so that the axial forces acting upon the forming machine in the feeding direction and being generated by the working process are reduced.

An advantageous further development of the invention provides that at least one recess, preferably all recesses of the surface structure being provided in the surface of the forming element are arranged orthogonally or essentially orthogonal to its longitudinal direction. These measures got the advantage that such an arrangement of the recesses of the inventive surface structure provides that only a very small torsion load acts upon the work piece, which is created when the forming tool rotates during the forming process around the stationary work piece. The recess being arranged orthogonally to the longitudinal direction and hence in the feed direction of the work piece therefore results in an advantageous way not only in small axial forces, but yields that the forming tool only impacts no or only a small torsion force on the work piece.

A further advantageous development of the invention provides that at least two recesses of the surface structure of the forming element of the inventive forming tool run parallel or at least essentially parallel to each other. Such a measure has got advantages in relation to a small torsion load of the work piece acted upon by the inventive forming tool, and in particular, if, according to a further advantageous development of the invention, it is provided that at least two recesses of the surface structure of at least one forming element run essentially straight.

A further advantageous development of the invention provides that at least two recesses of the surface structure of the inventive forming tool are arranged inclinedly to the longitudinal direction of the forming element. Such a measure results in that higher torsion load act upon the work piece as it would be in the case of recesses being arranged orthogonal to the longitudinal direction of the forming element and hence to the feed direction of the work piece. But the angled arrangement of the recesses of the surface structure has got the advantage that in the case of work pieces, for which a torsion load does not appear to be disturbing, a further reduction of the axial forces acting upon the feeding device and hence opposite to the feeding direction of the forming machine is achieved.

Further advantageous developments of the invention are the subject matter of the dependent claims.

Further details and advantages of the invention are given in the exemplary embodiment, which is described by means of the figures. They show:

FIG. 1: a front view of the exemplary embodiment,

FIG. 2: a longitudinal section through the forming tool of FIG. 1 along the line II-II,

FIG. 3: a schematical representation of the surface structure, and

FIG. 4: a schematical representation of a tool head of a swaging machine with a forming tool according to FIGS. 1 to 3.

Before in details the exemplary embodiment of a forming tool generally designated with 12 is described, for the sake of an easier understanding the basic actions occurring in a forming process carried out by means of such an forming tool are described: FIG. 4 shows a swaging head generally designated with 1 of a swaging machine, this means a tool head of a swaging machine, which has a swaging axle 2 and—in the case described—four swaging modules being radially slightable. Each swaging module has got a swaging plunger 10, having at its radially outer end a roller path 4, which is acted upon periodically by pressure rollers 6 being contained in a roller cage 5, in that the swaging axle 2 and/or the roller cage 5 is driven by an outer ring 7. The pressure rollers 6 hereby are supported by the outer ring 7. The swaging modules contain besides the swaging plunger 10 furthermore an adjustment plate 11 and the forming tool 12. Such a swaging head 1 is generally known and therefore it is not necessary to describe it further in details.

In order to produce from a tube- or rod-like initial work piece an end product, which has got in a first section still the non-reduced initial diameter of the initial work piece, which has got in a second section a diameter being reduced due to the forming process, and which has a transition section between the first and second section, in which the outer diameter of the work piece increases continuously from the reduced diameter to the initial diameter, so that in the final work piece the axially inclining transition section is formed, it is provided that the forming tool 12 has got—as it can be seen from FIG. 2—a forming element 21 being provided in a base body 12′ of the forming tool 12, which is arranged under a defined first angle of inclination α₁ to the central axis M of the forming tool 12 and hence to the feed direction of the work piece. Such a forming tool 12 is known and therefore there is no need to describe it further. For the sake of an easier understanding only it has got to be explained that the radial forming force, which is generated by the forming tool, creates, due to the angled arrangement of the forming elements 21, a force acting in the axial direction of the work piece, which stresses the work piece and must be compensated by a feeding device (not shown) of the forming machine, by means of which the work piece is fed during the forming process.

In order to better compensate these axial forces and to reduce the axial load of the work piece, which can lead to cripplings and bulgings, as well as the one of the feeding device, the described forming tool 12 now provides that in a surface 21′ of the forming element 21a—in relation to the surface 21—recessed surface structure 22 is provided, which has got (see FIG. 2) at least one recess 23 and usually a plurality of recesses 23. The detailed formation of the surface structure 22 is now described by means of FIG. 3, in which an exemplary embodiment thereof is shown. But it must be stressed that the angles, radii and further dimensions as well as the surface structure 22 shown there are only of exemplary nature and not to affect the generality of the following explanations:

FIG. 3 shows a cross section through the surface structure 22 shown in FIG. 2. One can see the surface 21′ of the forming element 21 of the forming tool 12 and further, that the surface structure 22 is not—as it is the case of the forming tool explained at the beginning —provided on the surface 21′, and is therefore not elevated. Contrary to that, it is provided that the recesses 23 are arranged in the surface 21′ of the forming element 21. In the exemplary embodiment described, the inclination of intake slope S of the forming element 21, namely the first angle of inclination, is α₁ =10°, in relation to the central axis M of the tool. Each of the recesses 23 has got a declining face 23a and an inclining face 23b, wherein—as shown in FIG. 4—the declining face 23a of the recess 23 is provided under a second angle of inclination of (in this case:) α₂=29° in respect to the intake slope S. The inclination of the faces 23a therefore has got a value of α₂−α₁ in respect to the central axis M. The inclination of the declining faces 23a of recesses 23 is oppositely orientated to the first angle of inclination α₁ defining the slope of the forming element 21 and the absolute value of the second angle of inclination α₂ is here larger than the one of the first angle of inclination α₁ of the forming tool 12. The opposite orientation of the inclinations of the forming element 21 and the declining faces 23a of the recesses 23 brings forth that the axial forces, which are generated by the swaging modules, are at least partially assimilated by the forming tool 12 and therefore do not act upon the work piece and/or the feeding device of the forming machine, since these axial forces are assimilated by the faces 23a being arranged oppositely to the inclination of the forming element 21. The declining faces 23a of the recesses 23 therefore form a kind of counter bearing for these axial forces and deviate them in the forming tool 12: The substance of the work piece of the areas being above the recesses 23 recede in these recesses, so that the declining faces 23a of the recesses 23 act upon the work piece in the feed direction.

It is evident for the person skilled in the art that the afore-mentioned exemplary values of the first angle of inclination of α₁=10° and of the second angle of inclination α₂=29° only have got an exemplary character. Important is only that the faces 23a are inclined in relation to the intake face S, so that the absolute value of the second angle of inclination α₂ is equal to the absolute value of the first angle of inclination α₁.

It must be noted in this context that the wave-like shape of the surface structure 22 is not compulsory. It is possible too to form the recesses 23 saw tooth-like, wherein the straightly declining face 23a of such a saw tooth at least partially assimilates the axial forces.

As it can be seen from FIG. 4, the surface structure 22 has got at least one, but in practice a plurality of recesses 23, which are preferably arranged parallel or essentially parallel to each other and—once again preferably—essentially orthogonal to the longitudinal direction of the forming tool 12 and in this way to the feeding direction V of the work piece. But it is possible too that at least one of the recesses 23 is not—as shown in the figures—provided orthogonal to the longitudinal direction of the forming tool 12, but it is arranged in a defined angle thereto.

Concludingly, it must be stated that the described design of the forming tool 12 with a recessed surface structure 22 in combination with the described formation of the recesses 23 and in particular with the one of the declined faces 23a, a forming tool 12 is generated which excels in that a substantial reduction of the axial forces acting upon the work piece and/or the feed device of the forming machine is achievable.

Claims

1. Forming tool, in particular a swaging tool, having a base body (12′), in which at least one forming element (21) is provided, which is inclined at a first angle of inclination (α1) to a central axis (M) of the forming tool (12), thereby determining an intake slope (S) of the forming element (21), characterized in that in the surface (21′) of the forming element (21) being inclined with the first angle of inclination (α1) a recessed surface structure (22) is formed, having at least one recess (23) with a declining slope (23a), and that the declining face (23a) of this recess (23) hast got, in relation to the intake slope (S) of the forming element (21) defined by the first angle of inclination (α1), a second angle of inclination (α2), which is orientated in the opposite direction with regard to the first angle of inclination (α1) and the absolute value of which is larger than or equal to the absolute value of the first angle of inclination (α1).

2. Forming tool according to claim 1, characterized in that the surface structure (22) is formed wave-like.

3. Forming tool according to claim 1, characterized in that at least one recess (23) is formed saw tooth-like.

4. Forming tool, according to claim 1, characterized in that at least two recesses (23) of the surface structure (22) of at least one forming element (21) of the forming tool (12) are arranged essentially parallel to each other.

5. Forming tool, according to claim 1, characterized in that at least one recess (23) of the surface structure (22) of at least one forming element (21) of the forming tool (12) is provided essentially orthogonal to the longitudinal direction of the forming tool (12).

6. Forming tool, according to claim 1, characterized in that at least one recess (23) of the surface structure (22) of at least one forming element (21) of the forming tool (12) runs essentially straight in a direction orthogonal to the feed direction (V) of the work piece.

7. Forming tool, according to claim 1, characterized in that at least one recess (23) of the surface structure (22) of at least one forming element (21) of the forming tool (12) is formed curved or wave-like.

8. Forming tool, according to claim 1, characterized in that at least one recess (23) of the surface structure (22) of at least one forming element (21) of the forming tool (12) is arranged angled to the longitudinal direction of the forming tool (12).

9. Forming machine, in particular a swaging machine, having a forming tool (12) for radially impacting a work piece, characterized by a forming tool (12), according to claim 1.

10. Forming machine, in particular a swaging machine, having a forming tool (12) for radially impacting a work piece, characterized by a forming tool (12), according to claim 2.

11. Forming machine, in particular a swaging machine, having a forming tool (12) for radially impacting a work piece, characterized by a forming tool (12), according to claim 3.

12. Forming machine, in particular a swaging machine, having a forming tool (12) for radially impacting a work piece, characterized by a forming tool (12), according to claim 4.

13. Forming machine, in particular a swaging machine, having a forming tool (12) for radially impacting a work piece, characterized by a forming tool (12), according to claim 5.

14. Forming machine, in particular a swaging machine, having a forming tool (12) for radially impacting a work piece, characterized by a forming tool (12), according to claim 6.

15. Forming machine, in particular a swaging machine, having a forming tool (12) for radially impacting a work piece, characterized by a forming tool (12), according to claim 7.

16. Forming machine, in particular a swaging machine, having a forming tool (12) for radially impacting a work piece, characterized by a forming tool (12), according to claim 8.