Forming machine and method for forming

Abstract

The invention relates to a forming machine for forming a tubular workpiece, comprising a machine base body, a first main spindle unit, to which a first spinning mandrel is attached and can be driven to rotate about a main spindle axis, and a second main spindle unit, on which a second spinning mandrel is attached and can be driven to rotate about the main spindle axis, wherein the second main spindle unit is axially opposite the first main spindle unit and the two main spindle units can be axially adjusted between a forming position, in which the workpiece is axially clamped between the first main spindle unit and the second main spindle unit, and a set-up position, in which the first main spindle unit is axially spaced apart from the second main spindle unit for introducing and removing the workpiece. The forming machine further comprises at least one first forming roller unit, which can be moved to the clamped and rotationally driven workpiece to carry out forming, and at least one second forming roller unit, which can be moved to the clamped and rotationally driven workpiece to carry out forming.

Description

[0001] The invention relates to a forming machine for forming a tubular workpiece, comprising a machine base, a first main spindle unit to which a first chuck is attached and rotatably driven about a main spindle axis, a second main spindle unit to which a second chuck is attached and rotatably driven about the main spindle axis, wherein the second main spindle unit is axially opposite the first main spindle unit, at least one first forming roller unit which can be positioned for forming the clamped and rotatably driven workpiece, and at least one second forming roller unit which can be positioned for forming the clamped and rotatably driven workpiece, according to the preamble of claim 1.

[0002] The invention further relates to a method for forming according to the preamble of claim 12.

[0003] From DE 10 2006 057 106 B3, a method and a spinning machine for producing a drum-shaped workpiece are known. In this process, a pot-shaped preform is clamped onto a two-part spinning chuck and set into rotation. The circumferential wall is formed by means of at least one forming roller. This known method can be used, in particular, to efficiently produce rim rings for vehicle wheels.

[0004] Another method for cylindrically stretching a preferably welded and calibrated sheet metal ring is disclosed in DE 101 15 815 A1. This method is characterized by particularly simple tools and a simple machine design and process. Excess material due to wall thickness variations in the starting material or sheet metal can be compensated for by special compensation areas in the finished part, where different wall thicknesses can develop. Furthermore, volume or length differences following the flow forming process can be eliminated by turning or trimming.

[0005] It is also known to form a welded sheet metal ring into a preform by widening the two open ends, which is then partially thinned in the two conically widened areas by projection. The angle of the die must be precisely matched to the material thinning. Such a method and a device for producing a pneumatic tire rim are described, for example, in WO 2004 / 035243 A1.

[0006] The generic designation JP-A-59185532 describes a forming machine in which a left-hand chuck is axially fixed in relation to the machine frame, while an opposing right-hand chuck is axially displaceable for receiving and clamping the workpiece.

[0007] In JP-A-2012 245551, a forming machine is shown in a highly schematic form, in which an axial force can be exerted on both sides of a ring-shaped workpiece by means of press rams.

[0008] Spinning or forming machines for shaping tubular workpieces, particularly for manufacturing rims for vehicle wheels, involve considerable investment costs. This results in correspondingly high machine hour rates. Therefore, there is a need for the most time-efficient machining and manufacturing of such workpieces on forming machines.

[0009] The invention is based on the Task The aim is to specify a forming machine and a method for forming a tubular workpiece, with which a particularly efficient chipless forming of a tubular workpiece can be achieved.

[0010] The problem is solved according to the invention by a forming machine having the features of claim 1 and a method according to claim 12. Preferred embodiments of the invention are specified in the dependent claims.

[0011] The forming machine according to the invention is characterized in that the at least one first forming roller unit is assigned to the first main spindle unit and has a first roller shaft, at one end of which a first forming roller is attached and the other end of the roller shaft is directed towards the first main spindle unit, that the at least one second forming roller unit is assigned to the second main spindle unit and has a second roller shaft, at one end of which a second forming roller is attached and the other end of the second roller shaft is directed towards the second main spindle unit, and that the two forming roller units are adjustable for the simultaneous forming of the workpiece.

[0012] In many forming machines today, the proportion of the cycle time spent on loading, unloading, and auxiliary movements is greater than the actual forming time. Therefore, reducing the number of traversing movements to achieve the shortest possible cycle time is of particular importance. This is achieved by the device concept according to the invention.

[0013] A fundamental aspect of the invention is that the forming chuck for shaping the inner contour of the ring-shaped workpiece is divided into two parts, with each of the two forming chucks being assigned at least one forming roller unit with a forming roller. This allows the movement required for clearing the workpiece for loading and unloading to be distributed between both forming chucks. Furthermore, both spindle units can be moved axially. This reduces the cycle time. The forming roller units are designed such that the forming rollers at the free end of the shaft are directed towards the center of the workpiece, while the other end of the shaft and the other elements of the forming roller unit face away from the workpiece and towards the respective side of the associated main spindle unit.This arrangement allows at least two axially opposed forming roller units to engage the workpiece simultaneously and perform a forming operation, particularly a forming roll. Compared to conventional forming machines, this type of forming can be achieved not only by multiple forming rollers radially opposed to each other, but also by forming rollers axially opposed to each other. This allows for a reduction in cycle time. The forming is preferably carried out by the forming roller units on the workpiece half corresponding to the respective forming chuck half. The forming areas on the forming chuck can be identical or, preferably, unequal, particularly with different lengths. Different forming speeds can be implemented on the forming chuck.

[0014] This arrangement according to the invention also shortens the approach and return movements of the forming roller units, which likewise leads to a reduction in cycle times. The forming roller units can thus be moved relatively quickly into a retracted setup position, allowing the two chuck halves to be moved axially apart, the workpiece removed, and a new workpiece inserted. Due to the overall small axial and / or radial stroke of the forming roller units, the necessary clearance to start the loading and unloading process is achieved very quickly, which has a positive effect on the overall cycle time.

[0015] In principle, the roller shafts of the forming roller units can be oriented parallel to the main spindle axis. According to a further development of the invention, it is particularly preferred that a shaft axis of the first forming roller unit and / or the second forming roller unit is oriented at an angle between 5° and 85° to the main spindle axis. This inclination allows the respective forming roller to be positioned almost perpendicular to the material, particularly when forming a rim bed, especially a drop-center rim. This enables the forces to be absorbed almost optimally by the bearings of the forming roller unit. Furthermore, this roller arrangement results in a particularly high-quality surface finish.

[0016] According to a further embodiment of the invention, it is preferred that two first forming roller units are provided, each arranged offset from one another by 180° and forming a first pair of forming rollers, and that two second forming roller units are provided, each arranged offset from one another by 180° and forming a second pair of forming rollers. This arrangement allows transverse forces on each half of the die to compensate for each other when the forming roller units are symmetrically positioned. Furthermore, the forming speed increases with the number of forming roller units, which also has a positive effect on the cycle time. In principle, a set of forming roller units can also comprise three or more forming roller units, which are then arranged at an equal circumferential distance from one another.

[0017] A particularly advantageous embodiment is achieved by arranging the first pair of forming rollers offset from the second pair by an angle of between 70° and 110°, preferably by 90°. This prevents the axially opposed forming roller units from being restricted in their axial movement, thus enabling machining of the first pair of forming rollers in the area of ​​the second die and, conversely, machining of the second pair of forming rollers on the opposite first die. This also has a beneficial effect on the workpiece quality and the cycle time. The forming roller pairs can be moved simultaneously or, preferably, unequally. In particular, the rims are designed asymmetrically so that, for example, the forming roller pairs can be moved at different feed rates.

[0018] In principle, the forming roller pairs can be arranged in a common horizontal or vertical plane, as in conventional forming machines. A particularly advantageous embodiment of the forming machine according to the invention is achieved by arranging the forming roller pairs at an angle to the horizontal and vertical planes. Thus, the planes in which the two forming units lie on one side can preferably have an angle between 15° and 75° to the horizontal and vertical planes, respectively. In a top view, this results in an X-shaped arrangement of the forming roller pairs, which are axially and radially offset from one another. This allows for particularly efficient use of the installation space in the area of ​​the main spindle axis.

[0019] A further advantageous embodiment of the forming machine according to the invention consists in the provision of a first support on which the first main spindle unit and the at least one first forming roller unit are mounted, and a second support on which the second main spindle unit and the at least one second forming roller unit are mounted. Preferably, the individual mountings, particularly of the forming roller units, are housed in an annularly closed support frame so that the high forming forces can be absorbed almost optimally. However, individual supports that are slidable relative to each other are also possible. The respective pairs of forming rollers are advantageously identical and can be moved axially and radially along the same path. For greater wall thickness reductions or good surface finishes, an axial and / or radial offset between the forming rollers can also be set.This can be manually adjustable or, in a preferred manner, automatically via a CNC control.

[0020] The forming roller units are mounted on the supports in a way that allows them to be moved and adjusted relative to the respective support and / or the associated main spindle unit.

[0021] In principle, the forming rollers of the individual forming roller units can be driven by friction from the rotating workpiece. For particularly high workpiece quality, a further development of the invention provides that at least one forming roller unit has at least one rotary drive for rotating the roller shaft. In particular, the rotary drive allows the forming roller unit to be driven synchronously with the rotating workpiece. The speed setting of the individual rotary drives of the forming roller units can preferably be performed automatically via the CNC control.

[0022] The outer die geometries can be symmetrical or, preferably, asymmetrical. The outer contour of the die depends on the desired inner contour of the workpiece to be formed. In the forming position, the two die halves are moved axially, preferably into contact with each other. This axial movement preferably allows for axial fixation or clamping of the preform in the subsequent deep-bed area of ​​a rim ring. Due to the forming process or the expansion for preform production, the preform in the deep-bed area may have tolerances that make sufficient torque transmission difficult at high forming rates.

[0023] To address this, a further development of the invention advantageously provides a clamping device for clamping and holding the workpiece on at least one chuck. The clamping device can, in particular, be a radial clamping device with extendable radial clamping jaws, which can be extended on the inner and / or outer circumference of the workpiece on at least one of the chucks. Furthermore, it is preferred that a clamping device enables the calibration of the drop center area of ​​a rim.

[0024] The forming machine according to the invention is provided with at least one handling device for loading and / or unloading the workpiece. For loading and unloading the rings, the two die chucks or spindle bearings are moved apart. The workpiece is preferably held in position by the handling device. The handling device may preferably have a gripper and / or two opposing scrapers. A gripper or scraper characterized by a slim design is particularly preferred, so that the workpiece is securely held in position during the movement, allowing the spindle units to be moved out of position simultaneously.

[0025] In a further development of the invention, it is particularly preferred that the handling device has a gripper arm which is arranged approximately centrally between the first main spindle unit and the second main spindle unit in the setup position. This allows the traverse movements of the two main spindle units and their respective forming roller units to be kept relatively small. Only a clearance of slightly greater than the axial length of the workpiece needs to be created between the two main spindle units.

[0026] The loading and unloading device is preferably designed to be so stable that it holds the raw or finished parts in a loading and unloading position, preferably in a fixed, defined position, without the need for auxiliary devices, when the press chucks are moved apart or together. Loading and unloading can also be performed by robots. The use of pneumatic parallel-stroke grippers is also possible. For cycle time reasons, a combined opening or closing movement can preferably be omitted.

[0027] In principle, a rotary drive can only be arranged on one of the main spindle units. The other main spindle unit would then rotate passively in the clamped position. According to one embodiment of the invention, a particularly efficient process is achieved by each having its own drive. Both main spindle units are equipped with an axial traverse drive.

[0028] The axial traverse of the two main spindle units is preferably achieved via an axial feed for the first main spindle side and another for the second main spindle side, which can also be called the tailstock side. Suitable measuring systems can be provided to ensure the position. Alternatively, the feed can also be combined with the carriage feed. Traverse movements can be performed with a single axis.

[0029] For clamping the workpiece, one main spindle unit is preferably moved against a stop and / or the other main spindle unit is designed with a lower axial force. Position is monitored by measuring systems, allowing for different speeds and / or positions. Furthermore, the clamping force on the second main spindle is automatically adjusted by a CNC controller depending on machine or process parameters. Alternatively, both could be configured as CNC axes with identical forces.

[0030] The invention also includes, in principle, a forming method for forming a tubular workpiece, in particular with the forming machine described above, wherein a first main spindle unit, to which a first chuck is attached, is driven rotatingly about a main spindle axis, a second main spindle unit, to which a second chuck is attached, is driven rotatingly about the main spindle axis, wherein the second main spindle unit is axially opposite the first main spindle unit, and the two main spindle units are axially adjusted relative to each other between a forming position, in which the workpiece is axially clamped between the first main spindle unit and the second main spindle unit, and a setup position, in which the first main spindle unit is axially spaced from the second main spindle unit for feeding and removing the workpiece.at least one first forming roller unit is positioned towards the clamped and rotating workpiece for forming, and at least one second forming roller unit is positioned towards the clamped and rotating workpiece for forming, characterized in that the at least one first forming roller unit is assigned to the first main spindle unit and has a first roller shaft, at one end of which a first forming roller is attached and the other end of the first roller shaft is directed towards the first main spindle unit, that the at least one second forming roller unit is assigned to the second main spindle unit and has a second roller shaft, at one end of which a second forming roller is attached and the other end of the second roller shaft is directed towards the second main spindle unit, and that the two forming roller units are positioned towards the workpiece for forming simultaneously.

[0031] The process may involve producing at least two different wall thicknesses per side by projection, projection roll forming, and / or roll forming. It is also preferably possible to roll over the open ends of the workpiece or to not stop or release the forming rolls before reaching the end of the material. Preferably, the forming speeds and / or the degree of surface and wall thickness reduction are adapted to the requirements of the rim.

[0032] The invention is further described below with reference to a preferred embodiment, which is schematically illustrated in the accompanying drawings. The drawings show: Fig. 1 a schematic side view of essential components of a forming machine according to the invention during loading; Fig. 2 a side view of the forming machine of Fig. 1at the start of the forming process; where, for the sake of clarity, only one forming roll of the second forming roll units is shown; Fig. 3 a side view accordingly Fig. 2 at the end of the forming process; and Fig. 4 a side view accordingly Fig. 1 when removing the formed workpiece.

[0033] A forming machine 10 according to the invention in various processing states is described in the Figures 1 to 4 depicted. This shows Fig. 1A setup position of the forming machine 10 in which the first main spindle unit 12 with the first die chuck 14 and the second main spindle unit 16 with the second die chuck 18 are axially separated, so that a gap is formed between the two halves of die chucks 14 and 18. A workpiece 5 to be formed is moved coaxially to a main spindle axis 20 between the first die chuck 14 and the second die chuck 18 by means of a gripper arm 52 of a handling device 50 (shown schematically). A centering shoulder 15 is formed on the end face of the first die chuck 14, which can be inserted into a corresponding centering recess (not shown) on the second die chuck 18, so that the first die chuck 14 and the second die chuck 16 are arranged in a working position, in contact with each other, coaxially to the main spindle axis 20.

[0034] The first main spindle unit 12 with the first chuck 14 is associated with two identical forming roller units 22, which are arranged offset from each other by 180° about the main spindle axis 20. The two first forming roller units 22 form a first forming roller pair 30. Each first forming roller unit 22 has a first forming roller 24, which is attached to a free end of a first roller shaft 26 (shown only schematically). The first forming roller 24 is directed towards the workpiece 5, while the other end of the first roller shaft 26 is directed away from the workpiece 5. The first roller shaft 26 is rotatably mounted in a first housing 23 via bearings (not shown). The forming roller 24 can be driven by a rear first rotary drive 28, so that the first forming roller 24 can be moved at synchronous speed towards the clamped and rotating workpiece 5.

[0035] On the axially opposite side, a second pair of forming rollers 40 with two second forming roller units 32 is arranged. The second forming roller units 32 are identical in design to the first forming roller units 22 and accordingly have a second forming roller 34, a second housing 33, a second roller shaft 36, and a second rotary drive 38. The second forming roller units 32 are also arranged such that the second forming rollers 34 are directed towards the workpiece 5, while the second roller shafts 36 are directed away from the workpiece 5.

[0036] Fig. 1It can further be seen that the first forming roller pair 30 and the second forming roller pair 40 are each arranged relatively close to their respective first forming chuck 14 and second forming chuck 18 in the setup position. Therefore, the forming units 22 and 32 do not have to travel long distances between the setup and machining positions, which has a positive effect on the cycle time.

[0037] According to Fig. 2The workpiece 5 to be formed, which has a conical preform on both sides, is axially clamped between the first die 14 and the second die 18 by corresponding relative axial movement of the two main spindle units 12, 16. In this axially clamped position, the workpiece 5 is driven in a rotary motion by a rotary drive (not shown), which can be arranged on either the first main spindle unit 12 or the second main spindle unit 16. The first forming rollers 24 of the first pair of forming rollers 30 contact an outer surface of the workpiece 5 in the area of ​​the first die 14, while the second forming rollers 34 of the second pair of forming rollers 40 contact the workpiece 5 primarily in the area of ​​the second die 18. The two pairs of forming rollers 30, 40 are rotated relative to each other by 90° so that a collision between the first forming rollers 24 and the second forming rollers 34 is avoided.The forming rollers 24, 34 can contact the workpiece (5) simultaneously. However, contact can also occur with a time delay, so that the torque requirement does not increase excessively. Due to different feed rates, the forming rollers 24, 34 can reach their end position simultaneously.

[0038] Through the action of the first forming units 22 and the second forming units 32, the wall thickness of the workpiece 5 is reduced in a defined manner, resulting in an axial elongation of the workpiece 5. In addition, the workpiece 5 is formed against the outer contour of the first die 14 and the second die 18, so that the dies 14 and 18 largely define the inner contour of the workpiece 5.

[0039] In the described procedure according to Fig. 3The forming rollers 24, 34 are initially positioned in a central area of ​​the workpiece 5, and then the forming rollers 24, 34, together with the corresponding forming units 22, 32, are moved outwards to the free ends of the workpiece 5. After the forming process is complete, the forming units 22, 32 only need to be moved a short distance away from the workpiece 5 to be in the setup position for loading and unloading the forming machine 10.

[0040] For unloading, according to Fig. 4The gripper arm 52 of the handling device 50 is again positioned against the formed workpiece 5, which in the illustrated embodiment is a rim for a motor vehicle wheel. After gripping the workpiece 5, the two die chucks 14, 18 with the corresponding main spindle units 12, 16 are moved axially apart again. The workpiece 5 can then be removed radially to the main spindle axis 20 via the gripper arm 52 and replaced by a new workpiece 5 to be formed.

Claims

1. Forming machine for forming a tubular workpiece (5), comprising - a machine base body, - a first main spindle unit (12), to which is attached a first spinning mandrel (14) which can be driven to rotate about a main spindle axis (20), - a second main spindle unit (16), to which is attached a second spinning mandrel (18) which can be driven to rotate about the main spindle axis (20), the second main spindle unit (16) being axially opposite the first main spindle unit (12), at least one first forming roller unit (22), which can be advanced to the clamped and rotationally driven workpiece (5) to carry out forming, and - at least one second forming roller unit (32), which can be advanced to the clamped and rotationally driven workpiece (5) to carry out forming, wherein the at least one first forming roller unit (22) is associated with the first main spindle unit (12) and has a first roller shaft (26), at one end of which is attached a first forming roller (24) and the other end of the first roller shaft (26) being directed towards the first main spindle unit (12), - the at least one second forming roller unit (32) is associated with the second main spindle unit (16) and has a second roller shaft (36), at one end of which is attached a second forming roller (34) and the other end of the second roller shaft (36) being directed towards the second main spindle unit (16), and - the two forming roller units (22, 32) can be advanced to carry out simultaneous forming of the workpiece (5), characterised in that - the two main spindle units (12, 16) are axially adjustable between a forming position, in which the workpiece (5) is axially clamped between the first main spindle unit (12) and the second main spindle unit (16), and a set-up position, in which the first main spindle unit (12) and the second main spindle unit (16) are axially spaced apart for supplying and removing the workpiece (5), wherein the necessary release movement for loading and unloading the workpiece (5) is split between the two spinning mandrels (14, 18), and - that for loading and / or unloading the workpiece (5) there is provided at least one handling device (50), which holds the workpiece (5) in a fixed defined position when the spinning mandrels (14, 18) are moved apart or together.

2. Forming machine according to claim 1, characterised in that a shaft axis of the first forming roller unit (22) and / or of the second forming roller unit (32) is oriented at an angle of between 5° and 85° to the main spindle axis (20).

3. Forming machine according to claim 1 or 2, characterised in that two first forming roller units (22) are provided, which are arranged offset from one another by 180° and form a first forming roller pair (30), and that two second forming roller units (32) are provided, which are arranged offset from one another by 180° and form a second forming roller pair (40).

4. Forming machine according to claim 3, characterised in that the first forming roller pair (30) is arranged offset from the second forming roller pair (40) by an angle of between 70° and 110°, preferably by 90°.

5. Forming machine according to one of claims 3 or 4, characterised in that the forming roller pairs (30, 40) are arranged in an inclined position relative to the horizontal and the vertical.

6. Forming machine according to one of claims 1 to 5, characterised in that a first support is provided, on which are mounted the first main spindle unit (12) and the at least one first forming roller unit (22), and a second support is provided, on which are mounted the second main spindle unit (16) and the at least one second forming roller unit (32).

7. Forming machine according to one of claims 1 to 6, characterised in that at least one forming roller unit (22, 32) has at least one rotary drive (28, 38) for rotationally driving the roller shaft (26, 36).

8. Forming machine according to one of claims 1 to 7, characterised in that a clamping device is provided for clamping and holding the workpiece (5) on at least one spinning mandrel (14, 18).

9. Forming machine according to claim 1, characterised in that the handling device (50) has a gripping arm (52) which is arranged approximately centrally between the first main spindle unit (12) and the second main spindle unit (16) in the set-up position.

10. Forming machine according to one of claims 1 to 9, characterised in that the two main spindle units (12, 16) each have a separate drive.

11. Forming machine according to claim 10, characterised in that a control unit is provided, with which a rotational speed of the rotary drives (28, 38) of the forming roller units (22, 32) can be matched to the rotational speed of the drives, such that there is preferably a uniform forming speed at the contact point on the workpiece (5).

12. Forming method for forming a tubular workpiece (5), in particular using a forming machine (10) according to one of claims 1 to 11, wherein a first main spindle unit (12), to which is attached a first spinning mandrel (14), is driven to rotate about a main spindle axis (20), a second main spindle unit (16), to which is attached a second spinning mandrel (18), is driven to rotate about the main spindle axis (20), the second main spindle unit (16) being axially opposite the first main spindle unit (12), - at least one first forming roller unit (22) is advanced to the clamped and rotationally driven workpiece (5) to carry out forming and at least one second forming roller unit (32) is advanced to the clamped and rotationally driven workpiece (5) to carry out forming, wherein the at least one first forming roller unit (22) is associated with the first main spindle unit (12) and has a first roller shaft (26), at one end of which is attached a first forming roller (24) and the other end of the first roller shaft (26) being directed towards the first main spindle unit (12), the at least one second forming roller unit (32) is associated with the second main spindle unit (16) and has a second roller shaft (36), at one end of which is attached a second forming roller (34) and the other end of the second roller shaft (36) being directed towards the second main spindle unit (16), and the two forming roller units (22, 32) are advanced simultaneously to the workpiece (5) to carry out forming, characterised in that - the two main spindle units (12, 16) are axially adjusted relative to one another between a forming position, in which the workpiece (5) is axially clamped between the first main spindle unit (12) and the second main spindle unit (16), and a set-up position, in which the first main spindle unit (12) is axially spaced apart from the second main spindle unit (16) for supplying and removing the workpiece (5), wherein the necessary release movement for loading and unloading the workpiece (5) is split between the two spinning mandrels (14, 18), and - that for loading and / or unloading the workpiece (5) there is provided at least one handling device (50), which holds the workpiece (5) in a fixed defined position when the spinning mandrels (14, 18) are moved apart and together.

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