Flow-forming machine and method for flow-forming

Abstract

The invention relates to a flow-forming machine and a method for flow-forming a substantially rotation-symmetric workpiece having a drum-shaped circumferential portion, comprising a spindle which can be driven in rotation about a spindle axis, a clamping device which is arranged on the spindle and has a plurality of clamping elements which are adjustable between a clamping position, in which the clamping elements abut against an outer circumferential region of the workpiece with a predetermined clamping force and hold the workpiece on the spindle for forming, and a release position in which the clamping elements are spaced from the workpiece in a defined manner for releasing the workpiece from the spindle, by means of a first actuating device, wherein the clamping force for holding the workpiece on the spindle during forming can be applied by the first actuating device, and a plurality of forming rollers which are radially and axially feedable to the drum-shaped circumferential portion for forming the circumferential portion of the workpiece. According to the invention, it is provided that a second actuating device is provided on the clamping device, by means of which a position of the clamping elements can be set in a radial direction for adapting to a diameter of the workpiece, and that a control device is provided, by means of which the second actuating device can be actuated depending on the diameter of the workpiece to be formed, wherein the clamping elements are radially pre-positioned depending on the diameter of the workpiece.

Claims

1. A flow-forming machine for flow-forming a substantially rotation-symmetric workpiece having a drum-shaped circumferential portion, comprising a spindle which can be driven in rotation about a spindle axis, a clamping device which is arranged on the spindle and has a plurality of clamping elements which are adjustable between a clamping position, in which the clamping elements abut against an outer circumferential region of the workpiece with a predetermined clamping force and hold the workpiece on the spindle for forming, and a release position, in which the clamping elements are spaced from the workpiece in a defined manner for releasing the workpiece from the spindle, by means of a first actuating device, wherein the clamping force for holding the workpiece on the spindle during forming can be applied by the first actuating device, and a plurality of forming rollers which are axially feedable to the drum-shaped circumferential portion of the workpiece and are radially and axially feedable for forming the circumferential portion of the workpiece, wherein a second actuating device is provided on the clamping device, by means of which a position of the clamping elements can be set in a radial direction for adapting to a diameter of the workpiece, and a control device is provided, by means of which the second actuating device can be actuated depending on the diameter of the workpiece to be formed, wherein the clamping elements are radially pre-positioned depending on the diameter of the workpiece.

2. The flow-forming machine according to claim 1, wherein the clamping elements are axially and/or radially adjustable between the clamping position and the release position by means of the first actuating device.

3. The flow-forming machine according to claim 1, Wherein the first actuating device comprises at least one actuating cylinder, which is hydraulically operated.

4. The flow-forming machine according to claim 3, wherein each clamping element is assigned an actuating cylinder by means of which the clamping element is displaceable in each case between the clamping position and the release position.

5. The flow-forming machine according to claim 1, wherein each clamping element is mounted on a rotatable disk eccentrically to a disk axis, wherein the disk axes are oriented parallel to the spindle axis, and the second actuating device has an actuator for rotating the disks with the clamping elements.

6. The flow-forming machine according to claim 1, wherein each clamping element is mounted on a radially displaceable or pivotable carriage, and the second actuating device is configured for radially displacing or pivoting the carriages.

7. The flow-forming machine according to claim 1, wherein the spindle axis is arranged vertically, and the clamping device is arranged suspended from the spindle, wherein a workpiece can be clamped from below.

8. The flow-forming machine according to claim 1, wherein at least one discharge opening is provided, and a suction device is provided, by means of which air and/or fumes can be suctioned-off through the at least one discharge opening.

9. The flow-forming machine according to claim 1, wherein a central centering pin is arranged on the clamping device, which pin is configured to be resilient and/or flexible.

10. The flow-forming machine according to claim 1, Wherein the control device is configured for supplying data concerning the diameter of the workpiece, and is connected to a control station and/or to at least one sensor for identifying the workpiece using the diameter of the workpiece.

11. The flow-forming machine according to claim 1, wherein for flexible forming of each individual workpiece, the control device controls a movement of the forming rollers during forming.

12. The flow-forming machine according to claim 1, wherein at least one outer forming roller and at least one inner forming roller are provided, which abut against an outer circumference or an inner circumference of the drum-shaped circumferential portion of the workpiece and which, for forming and shaping a wall thickness profile with changing wall thickness, are adjustable in the axial and radial direction relative to one another by the control device and/or a pitch angle of the at least one inner forming roller is variable.

13. The flow-forming machine according to claim 1, wherein two interchangeable spindles are provided, wherein a first interchangeable spindle is located in the working chamber, while a second interchangeable spindle is located in a loading and/or unloading position, wherein the two interchangeable spindles are displaceable alternately relative to one another.

14. The flow-forming machine according to claim 1, wherein a measuring device is arranged by means of which process-relevant dimensions or data of the workpiece can be identified prior to and/or after forming.

15. The flow-forming machine according to claim 1, wherein at least one cooling device and/or one heat-protective device are provided for semi-hot and/or hot shaping of the workpiece.

16. The flow-forming machine according to claim 1, wherein a quick-release clamping device, by means of which a semi-automatic or fully automatic roller change can be carried out, is arranged on an inner support (38) and/or an outer support on a bearing of at least one outer forming roller and/or at least one inner forming roller.

17. The flow-forming machine according to claim 1, wherein in a forming area the workpiece has a temperature differing from a clamping and centering area.

18. A method of flow-forming a substantially rotation-symmetric workpiece having a drum-shaped circumferential portion, the method comprising: providing a flow-forming machine comprising a spindle which can be driven in rotation about a spindle axis, a clamping device which is arranged on the spindle and has a plurality of clamping elements which are adjustable between a clamping position, in which the clamping elements abut against an outer circumferential region of the workpiece with a predetermined clamping force and hold the workpiece on the spindle for forming, and a release position, in which the clamping elements are spaced from the workpiece in a defined manner for releasing the workpiece from the spindle, by means of a first actuating device, wherein the clamping force for holding the workpiece on the spindle during forming can be applied by the first actuating device, a plurality of forming rollers which are axially feedable to the drum-shaped circumferential portion of the workpiece and are radially and axially feedable for forming the circumferential portion of the workpiece, a second actuating device on the clamping device, by means of which a position of the clamping elements can be set in a radial direction for adapting to a diameter of the workpiece, and a control device, by means of which the second actuating device can be actuated depending on the diameter of the workpiece to be formed, wherein the clamping elements are radially pre-positioned depending on the diameter of the workpiece, clamping the workpiece to the spindle by means of the clamping device, driving the spindle in rotation about the spindle axis, and radially and axially feeding the plurality of forming rollers to the workpiece for forming the circumferential portion, wherein the second actuating device is configured to adapt the position of the clamping elements to the diameter of the workpiece, and the control device is configured to actuate the second actuating device depending on the diameter of the workpiece to be formed, so that the clamping elements are radially pre-positioned depending on the diameter of the workpiece.

Description

(1) The invention is explained in more detail below with reference to preferred exemplary embodiments, which are shown schematically in the drawings. The drawings show in:

(2) FIG. 1 a perspective view of a flow-forming machine according to the invention without protective housing and loading and unloading device;

(3) FIG. 2 an enlarged view of the clamping device of the flow-forming machine according to the invention with a clamped workpiece in cross-section;

(4) FIG. 3 an enlarged, partially sectional, detailed perspective view of the clamping device according to FIG. 2;

(5) FIG. 4 another enlarged, partially sectional, detailed perspective view of the adjustment mechanism for the clamping device according to FIGS. 2 and 3;

(6) FIG. 5 a cross-sectional view of an alternative clamping device for a flow-forming machine according to the invention;

(7) FIG. 6 a top view of the clamping device of FIG. 5;

(8) FIG. 7 a perspective view of the clamping device according to FIGS. 5 and 6;

(9) FIG. 8 another cross-sectional view of the clamping device according to FIGS. 5 to 7, with the clamping element shown in the right half in the release position; and

(10) FIG. 9 another cross-sectional view of the clamping device according to FIGS. 5 to 8, with an intermediate position during clamping shown in the right half.

(11) A flow-forming machine 10 according to the invention and FIG. 1 has a base frame 12 with a total of three vertical columns 14, which enclose a working chamber. A total of two rotationally driven spindles 20 are mounted on a plate-shaped cover area 16 so as to be movable mounted and linearly slidable by means of linear drives 22 alternately between an outer loading and unloading position and a central working position.

(12) A clamping device 40 for picking up and holding a workpiece 5 in a suspended position is provided on the underside of each spindle 20 facing downward to the working chamber. Claw-shaped clamping elements 50 distributed along the circumference are arranged on the drum-shaped clamping device 40 for clamping the workpiece 5, which will be described in greater detail below.

(13) On each of the vertical columns 14, radially and vertically adjustable forming rollers 30 are provided, which can also be angled in principle, wherein an outer forming roller 30a is rotatably mounted in each case on an outer support 34 and an inner forming roller 30b is rotatably mounted in each case on an inner support 38. The inner rollers 30b are configured to run in an inner space of the workpiece 5, and the outer rollers 30a are configured to process an outer circumference of the workpiece 5, as is illustrated clearly in FIG. 2. The outer rollers 30a and the inner rollers 30b are displaceable axially and radially.

(14) According to FIG. 2, a drum-shaped workpiece 5, which is, in particular a cast or forged blank for a vehicle wheel, is clamped at and suspended from the clamping device 40. The workpiece 5 has a hub 6 with a center hole in which a centering pin 44 of the clamping device 40 engages for centering. For force-fit and form-fit holding, several claw-shaped clamping elements 50 are fed to a radially outer and upper edge of the workpiece 5 and the workpiece 5 is pressed axially against the chuck 40.

(15) The outer forming rollers 30a and the inner forming rollers 30b are each fed to a drum-shaped circumferential portion 7 of the workpiece 5 in pairs with respect to each other and can be displaced radially and/or axially with respect to each other to set a forming gap, so that the circumferential portion 7 can be flow-formed and an individual wall thickness profile with wall thickness changes can be formed. In particular, a thickened hump and a rim flange for receiving a vehicle tire can be formed on the circumferential wall portion 7.

(16) A structure of the clamping device 40 for a flow-forming machine 10 according to the invention is explained in greater detail below in conjunction with FIGS. 3 and 4. The drum-shaped clamping device 40 has an approximately pot-shaped housing 42, in which a first actuating device 60 is provided for axial adjustment of the claw-shaped clamping elements 50 in a vertical clamping direction. The clamping elements 50 are arranged on a lifting shaft 52, which is connected to an actuating cylinder 62 and/or a lifting plate 64 in order to move the clamping elements 50 between a lower release position and an upper clamping position.

(17) In the clamping position, a workpiece 5 is pressed upward by the clamping elements 50 against corresponding counterholders 54, which are mounted together with the respective clamping element 50 on a plate-shaped disk 74 of a second actuating device 70. The disk 74 has external teeth, which are connected via an intermediate gear 76 to a central actuator 78, which is configured as an externally toothed gear. A rotational movement of the central actuator 78 transmits a rotational movement via the intermediate gear 76 to the respective disk 74, on which the clamping element 60 with the lifting shaft 52 is mounted eccentrically to a disk axis 72. The rotary movement thus changes a radial distance between the clamping elements 50 and the central axis of rotation, so that radial pre-positioning of the actuators 50 for adaptation to a change in diameter of the workpiece 5 can be effected in a simple manner by adjusting the adjusting wheel 78.

(18) Around the circumference of the central actuator 78, a plurality of disks 74 each with a clamping element 50 and a counterholder 54 are arranged to clamp a workpiece 5 uniformly along the circumference.

(19) For axial clamping, the clamping force is generated by the respective actuating cylinder 62 on the clamping element 50 and/or a lifting plate 64, which can be activated by an axial lifting mechanism not shown for uniform actuation of all clamping elements 50. A spring device 68 at the upper end of the lifting shaft 52 can be used to preload and compensate for differences in thickness. In principle, an additional axial clamping force for clamping the workpiece 5 can also be applied via the spring clamping device 68.

(20) For concentric movement of the clamping elements 50 and the 54, a radial groove-shaped guide is provided in the guide disk 65 for each clamping element 50.

(21) For central diameter adjustment, a central adjustment element with position detection is provided above the spindle drives 20, which is connected to the multi-spline coupling 79 via a drive shaft and can counteract corresponding adjustment and centrifugal forces of the clamping elements 50.

(22) An alternative clamping device 40 for the flow-forming machine 10 according to the invention is shown in FIGS. 5 to 9. According to FIG. 5, the clamping device 40 has a drum-shaped base body, on the end face of which a plurality of clamping elements 50, specifically eight clamping elements 50, are arranged distributed along the circumference of the workpiece 5 for clamping a workpiece 5. Each clamping element 50 is adjustable together with an associated actuating cylinder 62 on a plate-shaped carriage 73 parallel to the central axis of rotation. The carriages 73 are mounted for radial displacement along radially oriented guide grooves in the drum-shaped base body. A central centering pin 44 is provided for centering the workpiece 5, which can be moved axially into a corresponding central opening in the workpiece 5.

(23) For clamping the workpiece 5, the clamping elements 50 are first in a release position, shown schematically in the right half of FIG. 8. In this release position, the carriages 73 of the second actuating device are displaced radially outward. At the same time, the clamping elements 50 are displaced axially upward by the actuating cylinders 62 as shown in FIG. 8.

(24) When all clamping elements 50 are in this release position, a workpiece 5 can be placed on and centered concentrically to the axis of rotation by means of the centering pin 44.

(25) The carriages 73 are displaced radially inward, preferably by actuating cylinders not shown, via the second actuating device not shown in more detail until the clamping elements 50 come into radial contact with the workpiece 5. This is clearly illustrated in the right half of FIG. 9.

(26) Starting from this pre-positioning by the second actuating device with the carriages 73, the workpiece 5 can now be firmly clamped by the clamping elements 50, wherein the state is achieved which is clearly shown in FIGS. 5 to 7. For this purpose, the clamping elements 50 are displaced downward via the actuating cylinders 62, wherein the workpiece 5 is thereby pressed against the base body of the clamping device 40 and firmly clamped. For releasing the workpiece 5, the clamping elements 50 can be displaced back in reverse order to their initial or release position according to FIG. 8.

(27) Also in this variant of the invention, a pre-positioning of the clamping elements 50 can be effected by means of the second actuating device by means of the preferably radially and linearly displaceable carriages 73. This enables the clamping device to efficiently clamp workpieces 5 with different outer diameters.

(28) In principle, the clamping or centering pin 44 can alternatively be configured as a jaw chuck so that it can clamp in the inner bore and/or externally on a sprue pin of the casting blank.

(29) In principle, the clamping element 50 can alternatively be axially fed to the workpiece 5 for clamping by a pivoting movement.