Device and method for continuously manufacturing shafts having varying inner and / or outer diameters, at least partially hollow

Abstract

An apparatus (1) for continuously manufacturing shafts which are at least partially hollow and have a varying inner diameter, comprising at least two forging tools (3) which are arranged centrosymmetrically around a forging axis (2) and which are drivable in the sense of a radial working stroke, a clamping head (4) for holding a cylindrical blank (5) which is at least partially hollow, a mating holding element (6) for axially supporting the blank (5), wherein the mating holding element (6) has a base (7) and a mating holding mandrel (9) which is arranged on the base (7) and which extends axially into a central cavity (8) of the blank (5), wherein the mating holding mandrel (9) is at least two-part, wherein a first part of the mating holding mandrel (9) is an inner part (10) and a second part of the mating holding mandrel (9) is an outer part (11) which surrounds the inner part (10), wherein at least the outer part (11) is axially movably configured relative to the inner part (10), and a method for continuously manufacturing shafts which are at least partially hollow and have a varying inner diameter under the condition of using such an apparatus (1).

Description

TECHNICAL FIELD

[0001] The invention relates to a device for continuously manufacturing a shaft which is at least partially hollow and has a varying inner diameter and / or outer diameter, comprising at least two forging tools which are arranged centrosymmetrically around a forging axis and which are drivable in the sense of a radial working stroke, a clamping head for holding a columnar blank which is at least partially hollow, and a counter-holding for axially supporting the blank, wherein the counter-holding has a base and a counter-holding mandrel which is arranged on the base and which axially extends into a central cavity of the blank, wherein the counter-holding mandrel is at least two-part, wherein a first part of the counter-holding mandrel is an inner part and a second part of the counter-holding mandrel is an outer part which surrounds the inner part, wherein at least the outer part is axially movably configured relative to the inner part, and to a method for continuously manufacturing a shaft which is at least partially hollow and has a varying inner diameter and / or outer diameter under the condition of using such a device. BACKGROUND

[0002] In the technical field of mechanical engineering, in particular automotive technology, shafts and axles are central elements. For reasons of weight reduction and resource protection, shafts and axles are increasingly manufactured from hollow materials, for example from tubular blanks as low-cost pre-products. For deforming the blanks, for example a radial forging method is used. For multiple deformations, i.e. deformations of blanks with different inner diameters and / or outer diameters, the blanks must usually be clamped around in separate component clamping units, which results in an increased "operating" outlay, higher cycle times and, as a result, also higher costs. SUMMARY

[0003] It is an object of the invention to provide a structurally simple device with which shafts with varying inner diameters and / or outer diameters can be continuously manufactured in a simple manner and method. It is also an object of the invention to provide an improved method for continuously manufacturing shafts with varying inner diameters and / or outer diameters under the condition of using a device according to the invention.

[0004] The stated requirements can be met by the device and the method according to the invention. Advantageous embodiments of the invention are described in the following.

[0005] The device according to the invention is used for continuously manufacturing a shaft which is at least partially hollow and has a varying inner diameter and / or outer diameter.

[0006] According to the invention, the device comprises at least two forging tools which are arranged centrosymmetrically around a forging axis and which are drivable in the sense of a radial working stroke, a clamping head for holding a columnar blank which is at least partially hollow, and a counter-holding for axially supporting the blank, wherein the counter-holding has a base and a counter-holding mandrel which is arranged on the base and which axially extends into a central cavity of the blank.

[0007] According to the application, the mating holding mandrel is at least two-part, wherein a first part of the mating holding mandrel is an inner part and a second part of the mating holding mandrel is an outer part surrounding the inner part, wherein at least the outer part is axially movably configured relative to the inner part.

[0008] The inner part thus has a smaller outer diameter than the outer part. The outer part thus has a larger outer diameter than the inner part.

[0009] The directional specification "axial" is to be understood in the context of the direction along or parallel to the forging axis. The directional specification "radial" is to be understood in the context of the direction normal to the forging axis.

[0010] The mating holding piece and / or the clamping head and / or the forging tool can be moved axially along the guide seat.

[0011] The mating holding mandrel of the mating holding piece is preferably of greater axial extension than the central cavity of the blank. That is to say, the mating holding mandrel is configured longer than the central cavity.

[0012] The method according to the application for manufacturing an at least partially hollow- configured shaft having a varying inner diameter and / or outer diameter under the conditions of using the device according to the application, comprises at least the following steps:

[0013] providing a cylindrical blank having a through hole at least partially penetrating the blank, the through hole constituting a central cavity of the blank,

[0014] clamping the blank into the clamping head such that the opening of the central cavity is placed on the end side of the blank facing away from the clamping head,

[0015] axially moving the clamping head together with the clamped blank to a first section of the blank,

[0016] axially feeding the mating holding piece or axially moving the clamping head such that the mating holding mandrel, i.e. the inner part and the outer part of the mating holding mandrel, axially completely penetrates the central cavity of the blank up to a defined stop, wherein the blank is pre-tensioned via the outer part,

[0017] radially feeding the forging tool to the first section of the blank,

[0018] forging a first shaft section having a first inner diameter in the region of the first section of the blank, wherein the first inner diameter is defined by the outer diameter of the outer part,

[0019] radially opening the forging tool,

[0020] - moving the outer part axially out of the central cavity of the blank in the direction of the base of the fitting holder, wherein the blank is pre-tensioned on the end side via the outer part,

[0021] - moving the clamping head together with the clamped blank axially to the second section of the blank, so that the inner part is located in the region of the second section and only partially penetrates the cavity,

[0022] - radially feeding the forging tool to the second section of the blank,

[0023] - forging the second shaft section, which has a second inner diameter in the region of the second section of the blank, wherein the second inner diameter is defined by the outer diameter of the inner part,

[0024] - radially opening the forging tool,

[0025] - moving the inner part axially out of the central cavity of the blank in the direction of the base of the fitting holder, wherein the blank is released on the end side via the outer part,

[0026] - axially taking the blank, now the finished shaft, out of the clamping head.

[0027] By virtue of the improved configuration of the device according to the application, a radial forging method can be implemented which is distinguished, inter alia, by low "operational" outlay, low cycle times and, as a result, low costs. BRIEF DESCRIPTION OF DRAWINGS

[0028] In the following, the application is described by way of example with reference to the drawings.

[0029] Figure 1 A schematic view of an exemplary blank before the forging process is shown.

[0030] Figure 2 A schematic view of an exemplary blank after the first forging process according to the application is shown, which has a first inner diameter and a first outer diameter. Figure 1

[0031] Figure 3 A schematic view of a finished shaft, i.e. an exemplary blank after the first and second forging processes according to the application is shown. Figure 1

[0032] Figure 4 A schematic sectional view of the device in the initial position is shown.

[0033] Figure 5 A schematic sectional view of the device during the first forging process is shown.

[0034] Figure 6 A schematic sectional view of the device between the first forging process and the second forging process is shown. ​​

[0035] Figure 7 schematic cross-sectional view of the device during a second forging process is shown.

[0036] Figure 8 schematic cross-sectional view of the device after two forging processes is shown.

[0037] Figure 9 perspective view of the blank and the forging tool is shown.

[0038] Figure 10 schematic cross-sectional view of the device during a second forging process is shown. Figure 9 front view along the viewing direction of the directional arrow 12. DETAILED DESCRIPTION

[0039] Figures 1 to 3 schematic views of the blank 5 in different forging stages are shown, respectively. Thus, Figure 1 the blank 5 before the forging process is shown, Figure 2 the blank 5 after the first forging process is shown, and Figure 3 the blank 5 after the first and second forging processes is shown, now being the finished shaft. In Figures 4 to 8 the device 1 in the respective forging stages is shown, respectively.

[0040] According to Figure 1 the blank 5 is a raw material for manufacturing a shaft having varying inner diameters i1, i2 (and varying outer diameters a1, a2) and is constructed in a cylindrical manner, partially hollow with a central cavity 8. In the present embodiment, the blank 5 is a one-sided closed extrusion blank. Thus, the blank 5 is closed at a first end side and open at a second end side opposite the first end side, wherein the opening at the second end side is part of the central cavity 8 of the blank 5.

[0041] The device 1 comprises four forging hammers 3 which are arranged centrally symmetrically around the forging axis 2 and which are drivable in the sense of a radial working stroke. The forging hammers and their arrangement relative to the blank 5 are shown in particular in Figure 9 and Figure 10 .

[0042] Furthermore, the device 1 comprises a clamping head 4 for holding the blank 5, wherein the blank 5 is held at the clamping head 4 on its closed end side.

[0043] The device 1 also comprises a counter-holding piece 6 for axially supporting the blank 5, wherein the counter-holding piece 6 has a base 7 and a counter-holding mandrel 9 which is arranged on the base. The counter-holding mandrel 9 is configured such that it can be partially, axially extended into the central cavity 8 of the blank 5.

[0044] The fit holding mandrel 9 is composed of two pieces, wherein the first part of the fit holding mandrel 9 is an inner part 10 and the second part of the fit holding mandrel 9 is an outer part 11 which surrounds the inner part 10.

[0045] The outer part 11 is configured axially movably relative to the inner part 10.

[0046] The inner part 10 thus has a smaller outer diameter than the outer part 11. The outer part 11 thus has a larger outer diameter than the inner part 10.

[0047] The directional specification "axial" is to be understood in the context of the direction along or parallel to the forging axis 2. The directional specification "radial" is to be understood in the context of the direction normal to the forging axis 2.

[0048] The fit holding piece 6 and / or the clamping head 4 can be moved axially along the guide seat. The forging tool 3, i.e. the forging hammer, can be moved radially.

[0049] The fit holding mandrel 9 of the fit holding piece 6 has a greater axial extension than the central cavity 8 of the blank 5.

[0050] The method according to the invention for manufacturing an at least partially hollow- composed shaft with different inner diameters i1, i2 and different outer diameters a1, a2 under the conditions of using the device 1 according to the previous description, comprises at least the following steps:

[0051] - providing a cylindrical blank 5 which has a through hole which penetrates the blank 5 at least partially, which through hole constitutes a central cavity 8 of the blank 5 (a punched and extruded blank which is closed on one side: Figure 1 ),

[0052] - clamping the blank 5 into the clamping head 4 so that the opening of the central cavity 8 is placed on the end side of the blank 5 which faces away from the clamping head 4 ( Figure 4 ),

[0053] - moving the clamping head 4 together with the clamped blank 5 axially to the first section of the blank 5 ( Figure 4 ),

[0054] - axially feeding the fit holding piece 6 so that the fit holding mandrel 9, i.e. the inner part 10 and the outer part 11 of the fit holding mandrel 9, axially completely penetrates the central cavity 8 of the blank 5 up to a defined stop, wherein the blank 5 is pre-tensioned via the outer part 11 ( Figure 4 ),

[0055] - radially feeding the forging tool 3 to the first section of the blank 5 ( Figure 4 、 Figure 5 ),

[0056] forging a first shaft section having a first inner diameter i1 in the region of the first section of the blank 5, wherein the first inner diameter i1 is defined by the outer diameter of the outer part 11 Figure 5

[0057] radially opening the forging tool 3 Figure 6

[0058] axially moving the outer part 11 out of the central cavity 8 of the blank 5 in the direction of the base 7 of the mating holder 6, wherein the blank 5 is pre-tensioned on the end side via the outer part 11 Figure 6

[0059] axially moving the clamping head 4 together with the clamped blank 5 to the second section of the blank 5, so that the inner part 10 is located in the region of the second section and only partially penetrates the cavity 8 Figure 7

[0060] radially feeding the forging tool 3 to the second section of the blank 5 Figure 7

[0061] forging a second shaft section having a second inner diameter i2 in the region of the second section of the blank 5, wherein the second inner diameter i2 is defined by the outer diameter of the inner part 10 Figure 7

[0062] radially opening the forging tool 3 Figure 8

[0063] axially moving the inner part 10 out of the central cavity 8 of the blank 5 in the direction of the base 7 of the mating holder 6, wherein the blank 5 is released on the end side via the outer part 11 Figure 8

[0064] axially taking the blank 5, now a finished shaft, out of the clamping head 4 Figure 3 .

[0065] List of reference signs

[0066] 1 device

[0067] 2 forging axis

[0068] 3 forging tool

[0069] 4 clamping head

[0070] 5 blank

[0071] 6 mating holder

[0072] 7 base

[0073] 8 central cavity​​​​​​​​

[0074] 9 fitting holding mandrel

[0075] 10 first part (inner part)

[0076] 11 second part (outer part)

[0077] 12 directional arrow

[0078] i1 first inner diameter

[0079] i2 second inner diameter

[0080] a1 first outer diameter

[0081] a2 second outer diameter

Claims

1. An apparatus (1) for continuously manufacturing shafts that are at least partially hollow and have varying inner and / or outer diameters (i1, i2, a1, a2), said apparatus comprising: - At least two forging tools (3) that are symmetrically arranged around the forging axis (2) and can be driven in the sense of radial power stroke. - A clamping head (4) for holding the cylindrical blank (5) which is at least partially hollow; and - A retaining element (6) for axially supporting the blank (5), wherein the retaining element (6) has a base (7) and a retaining mandrel (9) disposed on the base (7) and extending axially into the central cavity (8) of the blank (5). The characteristic feature is that the mating retaining mandrel (9) is constructed in at least two parts, wherein the first part of the mating retaining mandrel (9) is an inner part (10) and the second part of the mating retaining mandrel (9) is an outer part (11) surrounding the inner part (10), wherein at least the outer part (11) is axially movable relative to the inner part (10).

2. The device (1) according to claim 1. Its features are, The retaining element (6) and / or the clamping head (4) and / or the forging tool (3) are capable of moving along the guide seat axial direction.

3. The device (1) according to claim 1 or 2. Its features are, The retaining mandrel (9) has a larger axial extension than the central cavity (8) of the blank (5).

4. A method for continuously manufacturing shafts, at least partially hollow in construction, having varying inner and / or outer diameters (i1, i2, a1, a2), using the equipment according to any one of claims 1 to 3, characterized in that, The method includes at least the following steps: - Provide a columnar blank (5) having a through hole that at least partially penetrates the blank (5) and the through hole forms a central cavity (8) of the blank (5). - Clamp the blank (5) into the clamping head (4) such that the opening of the central cavity (8) is positioned on the end side of the blank (5) facing away from the clamping head (4). - The retaining member (6) is axially fed or the clamping head (4) is axially moved such that the retaining mandrel (9), namely the inner part (10) and the outer part (11) of the retaining mandrel (9), axially and completely penetrates the central cavity (8) of the blank (5) to the defined stop, wherein the blank (5) is pre-tightened via the outer part (11). - The forging tool (3) is radially fed into the first section of the blank (5). - Forging a first shaft section, the first shaft section having a first inner diameter (i1) in the region of the first section of the blank (5), wherein the first inner diameter (i1) is defined by the outer diameter of the outer portion (11), - Open the forging tool (3) radially. - The outer portion (11) is axially moved out of the central cavity (8) of the blank (5) toward the base (7) of the mating retainer (6), wherein the blank (5) is pre-tightened at the end side via the outer portion (11). - Move the clamping head (4) axially together with the clamped blank (5) such that the inner part (10) is located in the region of the second section of the blank (5) and only partially penetrates the cavity (8). - The forging tool (3) is radially fed into the second section of the blank (5). - Forging a second shaft section, the second shaft section having a second inner diameter (i2) in the region of the second section of the blank (5), wherein the second inner diameter (i2) is defined by the outer diameter of the inner portion (10), - Open the forging tool radially (3). - The inner portion (10) is axially removed from the central cavity (8) of the blank (5) toward the base (7) of the mating retainer (6), wherein the blank (5) is released at the end via the outer portion (11). - The blank (5), now the made shaft, is axially removed from the clamping head (4).

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