Process and device for compression rolling a vehicle wheel

Abstract

The invention relates to a process and a device for compression rolling a workpiece (W), at least some parts of which have the shape of a hollow cylinder or a hollow truncated cone and which is formed into a vehicle wheel by the compression rolling process. In order to compression roll the workpiece on a rotatable main spindle with a main spindle mount (2) of a compression rolling device, the workpiece (W) is axially clamped between the main spindle with the main spindle mount (2) and a setter (3) and is rotated about the main rotational axis (HA) of the main spindle by means of the main spindle with the main spindle mount (2). The compression rolling process is carried out by means of at least one compression roll (4) arranged radially outside of the hollow cylindrical or hollow truncated cone-shaped workpiece (W). The invention is characterized in that a radially inner rotatable eccentric tool ring (5) is arranged radially within the workpiece (W) as a counter bearing for the workpiece (W) during the compression rolling process, said eccentric tool ring being at least radially movable and having a dedicated rotational axis (5A) which can be moved radially in parallel to the main rotational axis (HA) between a first position and a second compression rolling position that is radially offset to the first position. In the compression rolling position, the main rotational axis (HA) of the main spindle with the main spindle mount (2) also lies radially within the bore or the inner diameter of the eccentric tool ring (5) but is no longer aligned with the dedicated rotational axis (5A) of the eccentric tool ring (5).

Description

[0001] The invention relates to a method for manufacturing a vehicle wheel by means of press rollers from a workpiece that is at least partially hollow cylindrical or hollow truncated cone-shaped, according to the preamble of claim 1. The invention further relates to a corresponding press roller device.

[0002] A generic process is known from CN 111 112 428 A.

[0003] Spin forming is a manufacturing process within chipless forming technology. DIN 8583 further subdivides spin forming into cylinder spin forming and projection spin forming. In practice, the terms "stretching" or "drawing" are often used for cylinder spin forming instead of "spin forming." The term projection spin forming, also called "projecting" in practice, is always used when the forming process produces workpieces with conical or tapered shapes.

[0004] This application describes in particular a process for pressure rolling by which a hollow cylindrical or conical starting workpiece made of metal, in particular of an aluminium alloy, is formed into a vehicle wheel.

[0005] The forming of a vehicle wheel is typically achieved using one or more forming rollers, which are radially advanced from the outside towards the hollow cylindrical or truncated conical workpiece and, during the forming process, press it against the rotationally symmetrical forming die mounted on a main spindle. Throughout the entire forming process, the axes of rotation of the main spindle and the forming die are identical / congruent.

[0006] From DE 3 545 506 A, a device for the pressure rolling of hollow cylindrical workpieces is also known, consisting of a holder for clamping the workpiece and at least one pair of rollers that can be pressed against the walls of the workpiece, wherein one pressure roller engages the workpiece wall from the inside and the other roller from the outside, each held by a radially inner and a radially outer roller carrier on which the pressure rollers are rotatably mounted. The inner and outer rollers are each axially and radially movable. In this way, the axially extending outer surface of the workpiece is formed.

[0007] The method of DE 3 545 506 A has been taken up again more recently, for example in EP 3 351 313 A.

[0008] A disadvantage of each design is that the inner pressure rollers are axially and radially movable by means of an inner roller carrier that projects into the workpiece being formed. However, since only a relatively limited space is available within the workpiece to accommodate both the inner roller carrier and one or more of the inner pressure rollers, the radius of the inner roller must be relatively small compared to the radius of the workpiece being formed, which is a disadvantage.

[0009] The invention aims to solve this problem.

[0010] The invention solves this problem through the subject matter of claim 1. It also creates the press rolling device of claim 15.

[0011] According to the invention, a method for press rolling of a workpiece that is at least partially hollow cylindrical or hollow truncated cone-shaped, which is formed into a vehicle wheel by press rolling, is presented. In this process, the workpiece is axially clamped for press rolling on a rotatable main spindle, which is provided with a main spindle mount, in a press rolling device between the main spindle with the main spindle mount and a feeder, and is rotated with the main spindle or main spindle mount about its main axis of rotation.The pressure rolling process is carried out by means of at least one pressure roller arranged radially and axially from the outside to the hollow cylindrical or hollow truncated cone-shaped workpiece, wherein a radially inner, rotatable eccentric tool ring is arranged as a support within the workpiece to be formed, which is movable at least radially by means of an adjusting device and which has its own axis of rotation, which is movable at least between a first position in which it is aligned with or at least parallel to the main axis of rotation, and a second pressure rolling / forming position radially offset therefrom and parallel to the main axis of rotation.

[0012] The design, arrangement and adjustability of the eccentric tool ring is such that the main axis of rotation of the main spindle with the main spindle mount or a straight line aligned with it is always radially within the central bore of the eccentric tool ring, even in the forming / pressing position.

[0013] A particular advantage of this method is that the radius or diameter of the radially inner eccentric tool ring can be chosen to be large. For example, it can be larger than half the inner diameter of the workpiece to be formed, which was not possible with the prior art because an inner support or carrier had to be accommodated inside the workpiece or protrude into it. Instead, no "inner support" or "carrier" is required that extends into the workpiece during operation and allows axial and radial adjustment of the inner pressure roller's position. The carrier for the rotatable eccentric tool ring can instead be arranged and housed outside the workpiece to be formed.

[0014] The ability to adjust the eccentric tool ring's axis of rotation radially – also referred to as the eccentric axis – offers further advantages. For example, the thermal expansion of the eccentric tool ring during operation can be compensated for by radially adjusting the eccentric tool ring's axis of rotation. This eliminates the need for the often time-consuming preheating of the spinning tool when forming light alloy wheels.

[0015] Clamping the workpiece between a feedforward and a main spindle or main spindle mount, while additionally utilizing the radial adjustment of the eccentric tool ring, is simple and straightforward. A particularly complicated clamping system, potentially prone to dirt and repairs during operation, such as the one described in EP 3 351 313 A, is not necessary.

[0016] The workpiece can be designed, in particular, as an internally hollow, rotationally symmetrical preform of a vehicle wheel. The preform can preferably be made of a metallic material such as an aluminum alloy. It can be formed, in particular, by casting or forging. Alternatively, the method according to the invention can also be used for forming vehicle wheels from magnesium alloys or other metals or alloys.

[0017] Following further development, it can be advantageously provided that the eccentric tool ring is rotatably mounted in an eccentric tool ring carrier, either directly or via an adapter ring, outside the interior of the hollow cylindrical or truncated conical workpiece. It can also be advantageously provided that the eccentric tool ring carrier can be adjusted radially by means of an adjustment device. This device can be easily integrated into the die-casting machine in various ways. In this way, a functional eccentric unit is formed.

[0018] The eccentric tool ring carrier can be arranged on an axially non-movable element, in particular on a machine bed, so that the eccentric tool ring can only be adjusted radially by means of the adjusting device.

[0019] In another variant, the eccentric tool ring carrier can be arranged on an axially movable element, in particular on an axially movable intermediate crossbeam, so that the eccentric tool ring can be adjusted radially by means of an adjustment device and axially by means of the axially movable element (e.g., the intermediate crossbeam). This variant has the advantage that the entire eccentric unit can also be positioned axially via a CNC axis.

[0020] In conjunction with the CNC-controlled adjustment of the eccentric tool ring carrier, this also enables a so-called "free-form forming" process. In this configuration, the eccentric tool ring can be provided with a roller contour and can also move axially parallel to the outer forming roller. The forming process essentially takes place between the two roller contours. Because the eccentric tool ring carrier is attached to the intermediate crossbeam in this configuration, the area around the main spindle remains unobstructed, allowing the use of a standard wiper ring. This also permits the use of standard forming tools on such a machine.

[0021] In a preferred embodiment, particularly when the eccentric tool ring is moved only radially to form the workpiece, it is provided that the eccentric tool ring extends axially over the entire length of the axial area WA of the vehicle wheel to be formed by pressure rolling, or even beyond. Furthermore, it can then be advantageously provided that the eccentric tool ring has an outer profile / contour on its outer circumference that corresponds to the inner contour on the inner circumference of the vehicle wheel to be manufactured.

[0022] The CNC control system of the device is used to appropriately control / regulate the process and its variations. It controls and / or regulates the process according to its respective programming. Optionally, it can use sensors or computational methods to acquire and process temperatures and / or positions, forces, and potentially other process / procedure parameters, and then perform corresponding control or regulation.

[0023] With an optional further development, the rotatable eccentric tool ring can have its own rotary drive. In this way, the rotational speed and / or peripheral speed of the eccentric tool ring can be synchronized with the rotational speed and / or peripheral speed of the main spindle or the workpiece, which can have a beneficial effect on the forming process. With another further development, the rotatable eccentric tool ring can optionally have a temperature control device, preferably for cooling and / or heating, to maintain it at a temperature advantageous for the forming process during operation.

[0024] Advantageous embodiments of the invention are specified in the dependent claims.

[0025] The invention is described in more detail below with reference to the drawings and exemplary embodiments. Further advantages of the invention will also become apparent. The invention is not limited to the exemplary embodiments shown in the figures, but can also be implemented in other ways, in a manner that is literal or equivalent, within the scope of protection. Individual features, which are described below with reference to the figures, are not only feasible in the respective exemplary embodiment, but also in other exemplary embodiments, whether shown below or not. The following are shown: Fig. 1: in a) a partially cutaway view of a section of a first spinning device for forming a hollow cylindrical or truncated conical workpiece into a vehicle wheel by spinning; in b) the section from a) after the workpiece has been formed into a vehicle wheel; and in c) the spinning device from a) in an unloading position. Fig. 2: in a) to g) successive steps during the forming of a hollow cylindrical or truncated conical workpiece into a vehicle wheel by spinning with the first spinning device – shown here in a simplified form. Fig. 1a) to c) according to a first variant of a method according to the invention; Fig. 3: a partially cutaway view of a second flow forming device during the forming or flow forming of a hollow cylindrical or truncated conical workpiece; Fig. 4: in a) a partially cutaway view of a section of a second flow forming device for forming a hollow cylindrical or truncated conical workpiece into a vehicle wheel by flow forming; in b) the section from a) after the workpiece has been formed into a vehicle wheel and in c) the flow forming device from a) in an unloading position; Fig. 5 in a) to g) successive steps during the forming of a hollow cylindrical or truncated conical workpiece into a vehicle wheel by flow forming with the second flow forming device - shown here in a simplified form. Fig. 3 and Fig. 4a) to c) according to a second variant of a method according to the invention; Fig. 6 in a) and b) successive steps during the forming of a hollow cylindrical or hollow truncated cone-shaped workpiece into a vehicle wheel by press rolling with the second - shown here in simplified form - press rolling device made of Fig. 3 and Fig. 4a ) to c) according to a third variant of a method according to the invention.

[0026] Fig. 3 Figure 1 shows an exemplary forming machine according to the invention. The mechanical components are shown in particular. (Not shown in Figure 2.) Fig. 3 Shown are power supply units - for example for electrical energy - and a CNC control of the pressing device or pressing machine.

[0027] The die rolling device 1 of the Fig. 3The machine frame 1 is essentially frame-like and may include, for example, an upper crossbeam 101, one or more vertical supports 102, 103 and a machine base 104.

[0028] In this respect, the pressure rolling devices 1 of the Fig. 3 , 4 and 1 They must be built identically.

[0029] The following is an example of the implementation of the Fig. 1a-c and 2a-g described in more detail.

[0030] A main spindle or main spindle mount 2 is rotatably mounted on the machine frame 1 – here exemplified by the machine base 104 – and has a spindle axis of rotation. The spindle axis of rotation is hereinafter also referred to synonymously as the main axis of rotation HA. The direction parallel to it is designated as the axial direction a, and the direction radial to it as r. A rotary drive (not shown here) is used to rotate the main spindle, which has the main spindle mount. The main axis of rotation HA is shown here as oriented vertically, but it can be oriented differently in space, in particular horizontally.

[0031] The main spindle, or in particular its main spindle mount 2, can have spindle or mount sections 21, 22, 23 of different diameters in the axial direction. One of these spindle / mount sections 22 of the main spindle 2 is designed as a workpiece holder. It extends axially into a workpiece W to be formed and rests against an end face of the workpiece. The workpiece W to be formed can thus be placed onto the spindle / mount section 22. A section 23 at the free end of the main spindle or main spindle mount can engage in a centering bore WL of the workpiece W and preferably also pass through it.

[0032] Opposite the main spindle / workpiece mounting section 22 and also the main spindle / workpiece mounting section 23, a pre-assembler 3 is formed which is axially adjustable parallel to the main axis of rotation and relative to the main spindle or main spindle mounting 2.

[0033] The feeder 3 can be rotatably mounted on a crossbeam cylinder 106 and thus be axially adjustable relative to the crossbeam 101. The axial adjustability of the intermediate crossbeam 105 can be achieved, for example, with at least one, preferably two, feed cylinders 107 (see also Fig. 3 ).

[0034] The axial distance between the feeder 3 and the main spindle with the main spindle mount 2 is thus variable. If it is increased sufficiently, the workpiece W to be formed can be positioned and preferably clamped firmly between the feeder 3 and the then free end of the main spindle mount 2 for loading. Fig. 2a and 1c ). In this position of Fig. 1c The workpiece W, formed into a vehicle wheel by flow forming, can also be removed from the flow forming device after forming. It then has a radially outer rim profile (at the end of the reference numeral line to the reference numeral W).

[0035] The workpiece W to be formed is a hollow cylindrical or frustoconical workpiece with a hollow interior. It is used in particular for the manufacture of a vehicle wheel. It can have a radial section WR with a centering bore WL and an axial section WA. This is preferably supported by the spindle / mounting section 23 (see also Fig. 1b and 1c ) - or a pre-set section 303 of pre-set section 3 (see also Fig. 4b and 4c ) - completely or partially penetrated. The workpiece W can be clamped in such a way in the area of ​​its radial section WR between the feeder 3 and the main spindle or main spindle mount 2 that it rotates with the main spindle or main spindle mount 2 during machining, whereby the feeder 3 also rotates.

[0036] The actual forming process by pressure rolling is then carried out with at least one or more pressure roll(s) 4. This at least one pressure roll 4 is arranged radially outside the workpiece to be formed. It is held there by an outer roller carrier 41 – i.e., a roller carrier 41 arranged outside the cylindrical workpiece W (see also Fig. 3 ) and can be moved axially and radially. By adjusting the pressure roller 4 in a radial direction and, if necessary, moving it axially (in Fig. 1a (As indicated by three positions of the pressure roller 4), the workpiece W to be machined is transformed into a vehicle wheel.

[0037] An eccentric tool ring 5, which has its own radially adjustable eccentric tool ring rotation axis 5A, is provided as an inner abutment. The eccentric tool ring 5 has an inner through-opening, in particular a bore, extending axially through it.

[0038] The eccentric tool ring 5 is rotatably mounted in an eccentric tool ring carrier 52 by means of at least one bearing 51. The eccentric tool ring carrier 52 is also equipped with an adjusting device 53 for adjusting the radial, rotatably mounted position of the eccentric tool ring 51.

[0039] The eccentric tool ring carrier 52 for the rotatable eccentric tool ring 5 does not necessarily have to be located inside or engage with the workpiece W, as is the case in the prior art. Instead, it can also be located on the outside of the workpiece W. This allows the outer diameter 5AD of the eccentric tool ring 5 to be chosen to be smaller than the inner diameter WID of the workpiece W, but still relatively large compared to the prior art described above with internal pressure rollers. In particular, the outer diameter 5AD of the eccentric tool ring can be larger than half the inner diameter WID of the workpiece W, at least in the area WA to be formed and stretched. This was not possible in the prior art, as an inner pressure roller had to be arranged between the outer circumference of the inner roller carrier and the inner circumference of the workpiece W to be formed.

[0040] The only requirement is that the eccentric tool ring 5 or an adapter ring 54 connected to it in a rotationally fixed manner must be axially long enough to protrude axially outwards from the workpiece W and be rotatably mounted there.

[0041] The adjustment device 53 of the Fig. 1a-c This allows for adjustment of the radial, supported position of the eccentric tool ring carrier 52, which can be slidably mounted or guided, for example, in the manner of a slide. This radial adjustment results in a radial adjustment or displacement of the eccentric tool ring rotation axis 5A of the eccentric tool ring 5 relative to the main rotation axis, but in particular parallel to the main rotation axis (HA).

[0042] The adjusting device 53 can be designed such that the eccentric tool ring 5 is only or exclusively radially movable ( Fig. 1a-cHowever, according to another embodiment, the adjusting device 53 can also be designed such that the eccentric tool ring 5 is radially and axially movable. Further degrees of freedom of movement are conceivable.

[0043] By radially adjusting or moving the eccentric tool ring 5, this can be changed in both configurations - Fig. 1a - 1c and Fig. 4 a - 4c each move into a first position in which its eccentric tool ring rotation axis 5A is aligned with the main rotation axis HA of the main spindle or the main spindle mount ( Fig. 1b , Fig. 1c , 4b and 4c ). Since the outer diameter(s) of the essentially cylindrical main spindle mount 2 is / are smaller than the bore / inner diameter 5ID of the eccentric tool ring 5 ( Fig. 1b), the eccentric tool ring 5 is radially defective in this position all around to the workpiece W to be formed or already formed, as well as to the main spindle mount 2. The distance S ( Fig. 1b and 4b ) is greater than the difference between the inner diameter of the workpiece W and the outer diameter of the eccentric tool ring 5 WID, i.e., the distance s is greater than the maximum radial adjustment of the eccentric tool ring carrier 52 or the eccentric tool ring 5 required for the forming process.

[0044] Since the bore / inner diameter of the eccentric tool ring 5 is larger than the outer diameter 22 AD of the section 22 of the main spindle mount 2, which lies axially inside the eccentric tool ring 5, it is also possible to move the eccentric tool ring 5 radially into a second position (working position) for operation or forming. In this position, its axis of rotation / central axis 5A is radially offset by a distance from the main axis of rotation HA, or parallel to it, so that an eccentric rotation of the eccentric tool ring 5 relative to the main axis of rotation HA can occur during operation. However, even in the second position (working position), the actual forming position, the main axis of rotation HA of the main spindle or the main spindle mount 2 lies radially inside the bore or inner diameter of the eccentric tool ring 5. Fig. 1aThe eccentric tool ring does not touch the main spindle or the main spindle mount 2; instead, the two elements are separated by a gap in this position.

[0045] With the adjusting device 53, a radial position can thus be reached as a second position (working position) during operation, in which the eccentric tool ring 5 rests radially inside the outer pressure roller 4 on the inner circumference of the workpiece W during forming. The inner contact area is aligned radially – as in Fig. 1aAs shown, the contact area of ​​the outer pressure roller 4 is located on the outside of the workpiece W. During forming, the eccentric tool ring 5 can thus easily serve as a support (inner tool) for the workpiece W to be formed, against which the outer pressure roller 4 engages. Preferably, the axial area WA of the workpiece W to be formed, whose profile / contour corresponds to the profile of the rim or vehicle wheel, is formed by pressure rolling, whereby its wall thickness can be reduced, at least in sections.

[0046] In particular, if the eccentric tool ring 5 is moved only radially and / or is movable, it is advantageous for it to extend axially over the entire length of the axial section of the workpiece W to be formed by pressure rolling, or even beyond. It can then be advantageously further provided that the eccentric tool ring 5 has an outer profile / contour on its outer circumference that corresponds to the inner profile / contour on the inner circumference of the vehicle wheel to be produced. Ultimately, the outer profile / contour on the outer circumference of the eccentric tool ring 5 thus determines the profile of the rim or vehicle wheel after forming. With a suitable design of the profile / contour of the outer diameter of the eccentric tool ring 5, it is therefore possible to produce complex rim profiles or vehicle wheel profiles, e.g., with undercuts.

[0047] The advantage is that, after further development of the invention, it is very advantageously possible to produce vehicle wheels with different outer / inner dimensions but identical rim profiles (see example of the rim profile). Fig. 1c ) to manufacture with only one or the same or an identically designed eccentric tool ring.

[0048] This can be explained using an example. If the radial outer / inner rim profile of the vehicle wheels is the same, then, for example, the first wheels with a vehicle wheel diameter of 55.88 cm (22 inches) and other wheels with a vehicle wheel diameter of 53.34 cm (21 inches) can be manufactured using the same eccentric tool ring 5.

[0049] The eccentric tool ring 5 only needs to be moved to a different corresponding radius (radial adjustment / feed of eccentric tool ring t) relative to the main axis of rotation HA of the main spindle mount 2 (not shown) for the production of vehicle wheels with different outer / inner dimensions but identical rim profiles (radial adjustment / feed of eccentric tool ring t). Otherwise, the flow forming process can be carried out as described below, for example.

[0050] A first exemplary flow forming process – particularly feasible with the device described above – is described in the Fig. 2a to g depicted.

[0051] The Figures 2a - 2g Each figure shows only the workpiece W, the spindle mounting sections 22, 23 of the main spindle or the main spindle mount 2, the eccentric tool ring 5 and the pre-assembler 3.

[0052] For the transformation, the following steps are performed first: Athe main spindle or the spindle mounting sections 22 and 23 of the provided pressing device as well as the eccentric tool ring 5 on the one hand and the pre-assembler 3 on the other hand axially spaced ( Fig. 2a ), so that the workpiece W can be axially placed on the main spindle or the main spindle mount 2. In this position, the rotary axes 5A and HA of the eccentric tool ring 5 and the main spindle or the main spindle mount 2 are aligned.

[0053] Then the workpiece W is placed in a Step B clamped between the feeder 3 and the main spindle or the main spindle mount 2 ( Fig. 2c ).

[0054] The eccentric tool ring 5 is then inserted into a Step C radially around the feed stroke t with the adjusting device 53 ( Fig. 2d) . After this step, the main axis of rotation HA of the main spindle or the main spindle mount 2 is still radially within the bore or the inner diameter of the eccentric tool ring 5, but it no longer aligns with the axis of rotation 5A of the eccentric tool ring 5.

[0055] Then begins in Step D The forming of the workpiece W is carried out further. The one or more outer pressure rollers 4 are moved axially and radially, and in particular, the axial area 5A is stretched ( Fig. 2eDuring the forming process, the main spindle / main spindle mount 2 and the pre-positioner 3 are in a rotary motion. Through contact with or being driven by the workpiece W, the eccentric tool inner ring 5 also rotates about its own eccentric tool ring axis 5A. The rotatably mounted eccentric tool ring 5 can also be driven separately by an eccentric tool ring drive (not shown here); this is an option for further developing the process.

[0056] As soon as the transformation after one or more passes or... Step D, in which at least one pressure roller 4 is moved axially and / or radially along the outside of the workpiece W, the eccentric tool ring 5 is in a Step E by the adjusting device 53, it is moved back into a position in which there is a gap all around to the inner circumference of the workpiece W ( Fig. 2f This position corresponds to the position as in Fig. 2cThe diagram is shown, with the only difference being that the workpiece W is now formed into a vehicle wheel. Then, in a... Step F the clamping of the workpiece W is terminated or released and the formed workpiece - the vehicle wheel - is removed from the forming die ( Fig. 2g ).

[0057] The construction of the pressing device of the Fig. 4a - 4c it differs from that of the Figs. 1a to 1c , the process for forming the workpiece W can, however, be largely based on the forming process of the Fig. 2a - 2g are equivalent to.

[0058] After Fig. 4a-c In this embodiment of the die-casting device, elements of the pre-assembler are used. Fig. 1a-c to the main spindle / main spindle mount 2 and elements of the main spindle / main spindle mount 2 are transferred to the feeder 3. This constitutes a kind of kinematic reversal.

[0059] Thus, the upper part of the (here vertical as in Fig. 1a) lower main spindle / main spindle mount 2 designed as a type of workpiece mount 201, onto which the workpiece W to be formed is positioned relative to Fig. 1a It can be axially mounted or brought into contact with the workpiece rotated by 180°. This workpiece holder 201 is similar in terms of its mounting contour for the workpiece W to the pre-assembler 3 of the Fig. 1 shaped. The workpiece W is shaped here relative to Fig. 1a - 1c The workpiece is placed, rotated 180°, on the main spindle 2 and its workpiece holder 201. This means that the radial section WR is positioned vertically at the bottom, and the slightly conical / tapered or cylindrical axial section WA is open vertically at the top.

[0060] The pre-assembler 3 can consist of several cylindrical sections 301, 302, 303, which are moved axially – here vertically from above – by the traverse cylinder 106 or the like into the axial section WA of the workpiece W to clamp it. These pre-assembler sections 301, 302, 303 can correspond to the spindle / mounting sections 21, 22, 23 with respect to their outer contour, but are arranged on the pre-assembler 3 rotated by 180° relative to them, or form the pre-assembler itself. The pre-assembler is preferably axially movable independently of the intermediate traverse 105.

[0061] The eccentric tool ring 5 is arranged between the outer diameter of the pre-position section 302 and the inner diameter of the workpiece. This ring is rotatably mounted in an eccentric tool ring carrier 52, either directly or via an adapter ring 54, in a bearing 51. This eccentric tool ring carrier 52, together with the eccentric tool ring 5, is radially movable by means of an adjusting device 53. In this embodiment, the adjusting device 53 is fixedly arranged and positioned on the intermediate crossbeam 105.

[0062] The eccentric tool ring carrier 52 is again arranged axially on the outside of the workpiece W. An inner carrier is therefore not required for the eccentric tool holder ring 5. The adjustment device 53 can be easily arranged on the intermediate crossbeam 105 and, for example, be axially movable by means of the feed cylinders 107 of the intermediate crossbeam. It is thus axially movable independently of the feeder 3.

[0063] Otherwise, an exemplary pressing method using the pressing device of the Fig. 4a - 4c in Fig. 5a - 5g depicted.

[0064] The Figures 5a - 5g Each figure shows only the workpiece W, the pre-assembler sections 301, 302, 303 of the pre-assembler 3, the eccentric tool ring 5.

[0065] For the transformation, first a Step A the main spindle 2 and the pre-assembler 3, formed from the pre-assembler sections 301, 302, 303, are brought into an axially separated position ( Fig. 5a), so that the workpiece W can be placed axially onto the workpiece holder 201 of the main spindle 2 ( Fig. 5b In this position, the rotary axes 5A and HA of the eccentric tool ring 5, the main spindle 2, the workpiece holder 201 and the pre-assembler 3 were aligned.

[0066] Then the workpiece W is placed in a Step B clamped between the feeder 3 and the workpiece holder 201 on the main spindle 2 ( Fig. 5c ). The eccentric tool ring 5 is then inserted into a Step C radially around the feed stroke t with the adjusting device 53 ( Fig. 5d After this step, the main axis of rotation HA of the main spindle or the workpiece holder 201 and the pre-positioner 3 is still radially within the bore or the inner diameter of the eccentric tool ring 5, but it no longer aligns with the axis of rotation 5A of the eccentric tool ring 5.

[0067] Then begins in Step DThe forming of the workpiece W is carried out further. The one or more outer pressure rollers 4 are moved axially and radially, and in particular, the axial area 5A is stretched ( Fig. 5e During the forming process, the main spindle 2, the workpiece holder 201, and the feeder 3 are in a rotary motion. Through contact with or being driven by the workpiece W, the eccentric tool inner ring 5 also rotates about its own eccentric tool ring axis 5A. The rotatably mounted eccentric tool ring 5 can also be driven separately by an eccentric tool ring drive (not shown here), but this is merely an option for further developing the process.

[0068] As soon as the transformation after one or more passes or... Steps D, in which at least one pressure roller 4 is moved axially and / or radially along the outside of the workpiece W, the eccentric tool ring 5 is in a Step E by the adjusting device 53, it is moved back into a position in which there is a gap all around to the inner circumference of the workpiece W ( Fig. 5f This position corresponds to the position as in Fig. 5c The diagram is shown, with the only difference being that the workpiece W is now formed into a vehicle wheel. Then, in a... Step F the clamping of the workpiece W is terminated or released and the formed workpiece - the vehicle wheel - is removed from the forming die ( Fig. 5g ).

[0069] The procedure of Fig. 6 can the Fig. 5largely correspond. However, the eccentric tool ring 5 is provided here, preferably with a modified / optimized outer contour equal to or similar to a pressure roller, and is also moved axially during the forming process, so that the eccentric tool ring 5 can act like an internal pressure roller.

[0070] In summary, the eccentric tool ring 5 can in any case be moved at least radially between a first position in which its axis of rotation 5A is aligned with the main axis of rotation HA of the main spindle 2, the workpiece holder 201, and the pre-position 3, and a second position in which its axis of rotation 5A is radially offset from the main axis of rotation HA. The radial extent of the eccentric tool ring 5 is preferably such that, even in the second position, the main axis of rotation HA of the main spindle 2, the workpiece holder 201, and the pre-position 3 lies radially within the bore or the inner diameter of the eccentric tool ring 5ID, both in the second position (working position) and throughout the entire forming process.

[0071] An advantage is that the radius or diameter of the rotatable eccentric tool ring 5 can be chosen to be relatively large. It can be larger than half the inner diameter of the workpiece, which was not possible with the prior art. Furthermore, no "inner support" or "inner carrier" is required, which extends into the workpiece during operation and allows axial and radial adjustment of the position of the inner pressure roller.

[0072] It should be mentioned again that the rotatably mounted eccentric tool ring 5 can optionally have its own rotary drive. In this way, the rotational speed and / or peripheral speed of the eccentric tool ring 5 can be synchronized with the rotational speed and / or peripheral speed of the main spindle 2, the tool holder 201, the workpiece W, and the feeder 3. Reference sign

[0073] machine frame 1 traverse 101 Support 102, 103 Machine base 104 Intermediate truss 105 Crossbeam cylinders 106 feed cylinder 107 Main spindle / main spindle mount 2 Spindle / mounting sections 21, 22, 23 Outer diameter of spindle / mounting sections 22AD Workpiece holder 201 Preset 3 Pre-assembly sections 301, 302, 303 Push roller 4 Eccentric tool ring 5 Eccentric tool ring rotary axis 5A Bore / inner diameter of eccentric tool ring 5ID Outer diameter of eccentric tool ring 5AD Storage 51 Eccentric tool ring carrier 52 Adjustment device 53 Adapter ring 54 Main rotary axis, main spindle mount HA workpiece W Workpiece inner diameter WID radial section WR Axial area WA Centering hole WL Workpiece inner diameter WID axial feed / adjustment direction a radial feed / adjustment direction r radial circumferential distance between bore / inner diameter and eccentric tool ring for main spindle mounting s radial adjustment / feed eccentric tool ring t

Claims

1. Method for spin forming a workpiece (W) that is hollow cylindrical or hollow truncated conical in shape at least in sections, which is formed into a vehicle wheel by spin forming, wherein the workpiece (W) is axially clamped for spin forming on a rotatable main spindle with a main spindle mount (2) of a spin-forming device between the main spindle with the main spindle mount (2) and a front piece (3), and is rotated with the main spindle with the main spindle mount (2) about its main rotational axis (HA), wherein the spin forming is carried out by means of at least one spin forming roller (4) arranged radially outside relative to the hollow cylindrical or hollow truncated cone-shaped workpiece (W), wherein a radially inner, rotatable eccentric tool ring (5) is arranged radially inside the workpiece (W) as an abutment for the workpiece (W) during spin forming, which ring has its own axis of rotation (5A), characterized in that the radially inner, rotatable eccentric tool ring (5) is at least radially movable and in that the own axis of rotation (5A) is radially movable between a first position, in which it is aligned with the main rotational axis (HA) or is at least parallel thereto, and a second spin forming position radially offset therefrom parallel to the main rotational axis (HA), wherein the main rotational axis (HA) of the main spindle with the main spindle mount (2) also lies radially within the bore or the inner diameter of the eccentric tool ring (5) in the spin forming position.

2. Method according to claim 1, characterized in that in the first radial position, the main rotational axis (HA) of the main spindle with the main spindle mount (2) is aligned with the axis of rotation (5A) of the eccentric tool ring (5), and in that in the second spin forming position, which is radially offset from the first, it is no longer aligned with the own axis of rotation (5A) of the eccentric tool ring (5).

3. Method according to one of the preceding claims 1 or 2, characterized in that the eccentric tool ring (5) is rotatably mounted in an eccentric tool ring carrier (52) axially outside the interior of the hollow cylindrical or hollow truncated cone-shaped workpiece (W), wherein it is preferably provided that the eccentric tool ring carrier (52) is adjusted radially by means of an adjustment device (53).

4. Method according to claim 3, characterized in that the eccentric tool ring carrier (52) is arranged on an axially immovable element, in particular on a machine bed, so that the eccentric tool ring (5) can be adjusted exclusively radially by means of the adjustment device (53).

5. Method according to claim 3, characterized in that the adjustment device with the eccentric tool ring carrier (52) is arranged on an axially movable element, in particular on an axially movable intermediate crosshead (105), so that the eccentric tool ring (5) can be adjusted radially by means of an adjustment device (53) and axially by means of the axially movable element.

6. Method according to one of the preceding claims, characterized in that the eccentric tool ring (5) is not adjusted or is only adjusted radially during the spin forming of the respective workpiece, in particular before spin forming in order to load the device with a workpiece to be formed and to remove the formed workpiece after spin forming.

7. Method according to one of the preceding claims, characterized in that the eccentric tool ring (5) is adjusted axially and radially during the spin forming of the respective workpiece (W).

8. Method according to one of the preceding claims, characterized in that the eccentric tool ring (5) extends axially over the entire length of the axial section of the workpiece (W) to be formed by spin forming or beyond.

9. Method according to one of the preceding claims, characterized in that the eccentric tool ring (5) has an outer profile / outer contour on its outer circumference which corresponds to the inner contour on the inner circumference of the vehicle wheel to be manufactured.

10. Method according to one of the preceding claims, characterized in that thermal expansions during spin forming are compensated by radial adjustment of the axis of rotation (5A) of the eccentric tool ring.

11. Method according to one of the preceding claims, characterized in that the rotatable eccentric tool ring (5) has its own rotary drive and in that, preferably, the rotational speed and / or the circumferential speed of the eccentric tool ring (5) is synchronized with the rotational speed of the main spindle with the main spindle mount (2) or of the workpiece W.

12. Method according to one of the preceding claims, characterized in that the rotatable eccentric tool ring (5) has a temperature control device with which it can preferably be cooled and / or heated, wherein it is maintained at a preset temperature defined for the forming process during spin forming.

13. Method according to one of the preceding claims, characterized in that, by means of a CNC control, the radially inner eccentric tool ring (5) and the radially outer spin forming roller are moved axially and radially relative to each other during spin forming of the axial region, so that a defined wall thickness profile with different wall thicknesses is achieved.

14. Method according to one of the preceding claims, characterized in that vehicle wheels with different outer and / or inner dimensions but identical rim profiles are manufactured with only one or the same or identically designed eccentric tool ring (5), wherein the eccentric tool ring (5) for machining the vehicle wheels with different outer and / or inner dimensions but identical rim profiles is moved to a different corresponding radius relative to the main rotational axis of the main spindle mount (HA).

15. Device for carrying out the method according to one or more of the preceding claims, having a rotatable main spindle mount (2) and a front piece (3) for clamping the workpiece (W) to be formed, wherein at least one spin forming roller (4) arranged radially outside relative to the hollow cylindrical or hollow truncated cone-shaped workpiece (W) is provided for spin forming, wherein a radially inner, rotatable eccentric tool ring (5) is provided radially inside the workpiece as an abutment for the radially outer spin forming roller, which has its own axis of rotation (5A), characterized in that the radially inner, rotatable eccentric tool ring (5) is at least radially movable and in that the own axis of rotation (5A) is radially movable between a first position, in which it is aligned with the main rotational axis (HA) or is at least parallel thereto, and a second spin forming position radially offset therefrom, wherein the main rotational axis (HA) with the main spindle mount (2) also lies radially within the bore or the inner diameter of the eccentric tool ring (5) in the spin forming position.

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