EP1442808B1 - Flat rolling die - Google Patents

Abstract

Cold rolling machine comprises two profiled rollers (2, 4) moving in opposite directions and each arranged on a guide (52, 54) over a carriage (56, 58); and an adjusting device (38, 40) having an adjustment drive (44) via which the rollers can be adjusted during the rolling process. An independent claim is also included for a process for cold rolling a workpiece using the above machine. Preferred Features: The adjusting device has a guiding carriage (38, 40) for each guide, the guiding carriage being able to move on a bevel guide (34, 36).

Description

The invention relates to a rolling bar for non-cutting cold forming of profiles by cold rolling, the use of corresponding rolling rods in a cold rolling machine and a method for cold rolling a workpiece with corresponding rolling rods.

From the DE 197 28 669 A1 a method for forming a rotationally symmetrical hollow body on a cross rolling machine is described. The cross rolling machine comprises at least one transverse roll bar, which has a wedge-shaped profile.

From the US 3,303,682 For example, there is known a method of cold forming teeth on a cylindrical part, wherein the cylindrical part is held between a pair of reciprocating tool bars, the tool bars being movable in the opposite direction, and perpendicular to the tool bars in one direction is hammered to the reciprocating motion to gradually drive the tool bars into the cylindrical part.

From the DE 41 23 847 C2 a flat-jaw cross rolling machine is known, are formed in the tool carrier as a synchronous hydraulic cylinder.

From the US 4,045,988 For example, there is known a rotary forming machine having rotary tools having a partially circular forming side.

From the US 6,047,581 is a machine tool with tool bars known.

In cold rolling machines, the workpiece to be machined is clamped rotatably between two tips or other quick-release devices, this workpiece clamping device is usually associated with a feed axis. The desired profiling of the workpiece via two synchronously counter-rotating rolling rods, which impinge simultaneously on the workpiece and this initially by frictional engagement and later by positive engagement in rotation. In doing so, the material is introduced into the free spaces of the tool, i. displaced by the rolling rods. Usually, the height of the ground profile of the rolling rod increases in the forming area, so that each tooth of the rolling rod is pressed slightly deeper into the workpiece, as the preceding. Once the full tread depth has been reached, a calibration zone and a relaxation zone can follow, along which the geometry and surface quality of the workpiece are optimized.

This non-cutting cold forming of profiles, such as splines (straight or oblique), spiral teeth, oil grooves, threads or knurls is about thirty times faster than the machining of the profiles. Cold rolled workpieces also offer higher strength, better surface finish and high accuracy.

In the brochure "Special Machine Program XK" of the applicant, a cold rolling machine is presented, in which the two counter-rotating rolling rods are arranged in the horizontal direction, while the workpiece axis is also arranged in the horizontal direction transverse to the direction of movement of the rolling rods. A disadvantage of this solution is that due to the horizontal arrangement of the rolling rods a considerable width of the cold rolling machine is required. This known machine also has a hydraulic drive, the hydraulic unit requires a lot of space.

This disadvantage is achieved by a cold rolling machine according to the WO 99/43454 A1 overcome, in which the rolling rods are arranged in the vertical direction, so that the machine requires a much smaller footprint.

For dimensional corrections on the workpiece, it may be necessary to deliver the rolling rod in the radial direction (relative to the workpiece) in order to form the predetermined tread depth. This delivery is done manually via adjusting screws, over which the radial position of the rolling rods is adjustable relative to the workpiece. For this readjustment of the rolling process must be interrupted, so that the productivity of the system is reduced.

In contrast, the invention has for its object to provide a rolling rod and a method for cold rolling, through which the downtime during production are reduced.

This object is achieved with regard to the rolling rod by the features of patent claim 1.

The rolling rod according to the invention, which is used in particular for the production of cover toothings or spiral toothings, has a profiling which extends with a constant profile over substantially the entire effective surface of the rolling rod. Their production is thereby simpler than in the conventional rolling rods with increasing profile depth in the rolling direction.

A tread depth is substantially consistent along a range.

Calibration and relaxation zones can be formed at end sections. The calibration and relaxation zones may be formed by ramps.

The area extending between the ramps can be designed essentially with the same profile depth.

At the end portions of the profiling ramps can be formed with low tread depth. The ramps may be short ramps.

Advantageously, the length of the ramps is substantially less than the length with constant profiling.

Preferably, a rolling rod according to the invention is made of hardened and ground cold work steel.

The rolling rods according to the invention can be advantageously used in a cold rolling machine with an infeed device with an integrated feed drive, via which the rolling rods can be adjusted during the rolling process in the direction of engagement. That is, each rolling rod is associated with a feed axis, which allows an adjustment of the rolling rods in approximately radial direction with respect to the workpiece to be machined. By this feed device thus the tread depth can be changed during the rolling process, so that, for example, the desired Endprofiliefe not - as required in the prior art - during a feed movement of the rolling rods, but during several Walzstangenhüben can be formed, in which the rolling rods are readjusted in the radial direction. This makes it possible to minimize the length of the rolling rod, so that the dimensions of the cold rolling machine remain relatively low.

In this reversing operation, therefore, the profile is formed with several Walzstangenhüben, while in the known machines, the profile had to be rolled with only one stroke - it is obvious that the conventional method represents a much greater burden on the machine and the rolling rods.

Since the tread depth is determined by the feed device, the rolling rods can be carried out essentially with a constant tread depth, see above that their production is much easier than in the conventional rolling rods with increasing profile depth in the rolling direction. The calibration and relaxation zones described above can be formed by means of small ramps at the end sections of the rolling rods, wherein the region of the rolling rods extending between the ramps is formed essentially with the same profile depth.

In a particularly preferred embodiment, each of the two rolling rods is assigned in each case a guide carriage, which is displaceable along inclined guides. These two inclined guides are employed in a V-shaped manner with respect to one another, so that the radial distance between the rolling rod and the workpiece can be changed by displacing the guide carriage along the associated inclined guide. D. h., The feed movement is carried out by moving the roll bar along the wedge-shaped inclined guides, so that by adjusting the rolling rods without tool change a variation of the number of teeth, the rolling of even and odd numbers of teeth, a positioned rollers and the quality optimization of the profile by division correction possible is.

The feed movement can be carried out particularly precisely if each guide carriage is assigned its own feed drive, for example a planetary spindle drive. Alternatively, other suitable drives, such as rack drives, ball screw drives or hydraulic drives can be used.

The construction of the cold rolling machine can be further simplified if the free end portions of the sliding along the slanted guide rails are connected via a console on which the drives are stored for the rolling rod device.

The inventive concept can be used particularly advantageously in cold rolling machines, the rolling rods are driven in the vertical direction, so that the footprint of the machine according to the invention is minimal. The height can be minimized by driving the rolling rods in the horizontal direction.

According to the invention, the workpiece can be driven via the rolling rods transmitted forces or via its own rotary drive, which is synchronized with the drive of the rolling rods.

In an advantageous variant of the invention, the forming area of the workpiece is subjected to ultrasound. By this ultrasound, the flow limit is lowered during the forming process, so that the forming forces are reduced compared to conventional solutions.

The guide rails supporting the inclined guides are advantageously supported on two spaced support legs of a machine bed, these two support legs are connected to increase the rigidity over cross straps.

Other advantageous developments of the invention are the subject of the other dependent claims.

Figur 1

eine schematische Schnittdarstellung einer Kaltwalzmaschine;

Figur 2

eine geschnittene Draufsicht auf die Kaltwalzmaschine aus Figur 1 und

Figur 3

eine schematische Darstellung einer Walzstange aus Figur 1.

In the following a preferred embodiment of the invention will be explained in more detail with reference to schematic drawings. Show it:

FIG. 1

a schematic sectional view of a cold rolling machine;

FIG. 2

a sectional plan view of the cold rolling machine FIG. 1 and

FIG. 3

a schematic representation of a rolling rod FIG. 1 ,

FIG. 1 shows a section through a cold rolling machine 1, in which two rolling rods 2, 4 in the vertical direction (with respect to the footprint) are arranged, while a workpiece, not shown, the bearing headstock 6 (only indicated in FIG FIG. 1 ) in the horizontal direction, that is arranged parallel to the support surface. The workpiece is rotatably mounted in this headstock 6, wherein via an NC drive, not shown, for example, for feeding or removal of the workpiece from the processing area, before or after the rolling, a shift in the axial direction (perpendicular to the plane) is possible. The design of the headstock with a quill and a rear centering differs essentially not from conventional solutions, so that reference is made to the above-mentioned prospectus of the applicant with regard to further details for the sake of simplicity.

By the cold rolling machine, a variety of profiles, such as serrations, threads, running gears, oil grooves, grooves, knurls or other special forms can also be formed in reversing.

The control of the cold rolling machine 1 is according to FIG. 2 housed in laterally arranged cabinets 7. This extremely compact design with minimal footprint makes it possible to carry out the cold rolling machine 1 as a so-called hook machine, which is practically pre-assembled and delivered as a functional unit.

The illustrated cold rolling machine 1 has a base made of mineral cast, the two upwards (see FIG. 1 ) projecting support legs 10, 12 has. These each have a stepped recess with an in FIG. 1 visible horizontal support surface 14 and a vertical support surface ( FIG. 2 ) 16, on which one of the two support legs 10, 12 overstretching bridge structure 18 is supported. This is in FIG. 2 shown cut and contains essentially the guides and drives for the reciprocating movement of the rolling rods 2, 4th

The bridge structure 18 carrying the rolling rods 2, 4 has in each case one supporting body 20, 22 attached to the supporting legs 10, 12, which essentially consists of a cast-supporting structure 24, which is designed with a mineral casting filling.

In particular FIG. 2 can be removed, the two support bodies 20, 22 via a rear transverse tab 26 and a front transverse flap 28 are connected to each other, which extend beyond the area between the two support legs 10, 12. The end portions of the front cross-bar 28 are secured to the bearing surfaces of the support legs 10 and 12 formed by the horizontal support surface 14 and the vertical support surface 16. Both transverse straps 26, 28 each have a recess 30, 32, through which the workpiece with the associated clamping devices of the headstock 6 (indicated in FIG FIG. 2 ) can be feasible in the editing area.

As further in particular FIG. 2 can be removed, are formed at the opposite end faces of the two support bodies 20, 22 and the cast-support structure 24 oblique track guides 34, 36 in the form of flat track guides made of plastic, characterized by low friction, high accuracy, long life and optimal damping behavior distinguished. Along these inclined track guides 34, 36 is in each case a guide carriage 38, 40 guided, which is designed in the contact area with the two support members 20, 22 with guide legs which engage around the inclined track guide 34, 36. The determination of the guide carriage 38, 40 in the transverse direction ( FIG. 1 ) takes place via a counter guide 42, which engage behind the side surfaces of the flat track guide 36.

As in particular from FIG. 1 can be removed, the two end faces of the inclined rail guides 34, 36 are V-shaped against each other employed, so that their distance to the footprint decreases. The angle of attack of each flat track guide 34, 36 may be, for example, 3 °.

The axial displacement of the two guide slides 38, 40 takes place in each case via an NC drive 44, which can be embodied, for example, as a planetary spindle drive with servomotor 50. In each case, a spindle nut 46 is rotatably supported in the support body 22 and 24, while the planetary spindle 48 is mounted in a console of the guide carriage 38 and 40 and connected via a toothed belt with the servo motor 50. Depending on the direction of rotation of the servo motor 50, the planetary spindle 48 is rotated by the fixed spindle nut 46 and transmitted as axial displacement on the guide carriage 38, 40, so that they are displaced along the inclined track guides 34 and 36 respectively.

The end faces of the guide carriage 38, 40 remote from the inclined track guides 34, 36 run parallel to the feed axis of the two rolling rods 2, 4, so that the guide slides, 38, 40, in the representation according to FIG FIG. 1 have an approximately wedge-shaped cross-section. The rolling rods 2, 4 facing end surfaces of the guide carriage 38, 40 are also formed as guides 52, 54 along which slides 56, 58 are guided, on which the rolling rods 2, 4 are fixed.

The guides 52, 54 are also executed again as a cast flat rail guides and correspond in terms of structure substantially the inclined guides 34, 36. D. h., The carriages 56, 58 dive with their end face in a U-shaped recess of the associated guide carriage 38, 40, wherein this recess is designed as a sliding guide.

The determination of the carriage 56, 58 on the associated guide carriage 38, 40 via a counter-guide 60th

The in FIG. 1 via the two support legs 10, 12 also extending end portions of the two guide slides 38, 40 each have a bracket 62, in each of which an NC drive 64, 66 is mounted. These have virtually the same structure as the drive 44 for the guide carriage 38, 40th D. h., A planetary spindle 48 is (here via a toothed belt 68) ( FIG. 2 ) connected to a servomotor 50 and rotatably mounted in the bracket 62. The cooperating with the planetary spindle 48 spindle nut 46 is rotatably mounted in a respective carriage 56, 58, so that upon rotation of the planetary spindle 48, the spindle nut 46 and the associated carriage 56 and 58 along the guide 52 and 54 is moved. The planetary spindle 48 passes through an inner bore of the associated carriage 56, 58. The two NC drives 64, 66 are driven in such a way that the two rolling rods 2, 4 are offset in the counter-synchronized movements.

FIG. 3 shows a schematic representation of a rolling rod 2, as in the cold rolling machine 1 according to FIG. 1 can be used.

This rolling rod 2 is conventionally made of hardened and ground cold work steel and carries a profiling 70 whose tread depth S is substantially constant along a region T. At the two end portions of the profiling 70 ramps 72 are formed whose length U is substantially less than the length T with constant profiling 70. Due to the substantially constant profiling leaves the in FIG. 3 shown rolling rod much easier to produce than conventional rolling rods, where the tread depth in the range T is variable. Also the regrinding of in FIG. 3 shown rolling rod is due to the substantially constant tread depth much easier than in the conventional solutions.

FIG. 1 shows the basic position of the cold rolling machine 1, in which the carriage 58 is in its upper and the carriage 56 in its lower end position. In this basic position, the two guide slides 38, 40 are moved via the NC drives 44 into their upper end position, so that the distance between the rolling rods 2, 4 is maximum (minimum profile depth). In this basic position, the workpiece is brought over the headstock 6 in its processing position between the two rolling rods 2, 4.

Subsequently, both NC drives 64, 66 are driven synchronously and in opposite directions, so that the two rolling rods 2, 4 accumulate in opposite directions on the workpiece and these offset by frictional and positive engagement in rotation, said by the engagement between the workpiece and the two rolling rods 2, 4 the forming process takes place. The tread depth can be adjusted by a synchronous displacement of the two guide slides 38, 40 along the inclined surfaces 34, 36, wherein the maximum tread depth during a stroke of the rolling rods 2, 4 or during several successive strokes (also in reverse operation) is formed. By suitable inclination of the inclined guide 34, 36 and corresponding stroke of the NC drives, for example, a tread depth of up to about 5 mm can be produced. The rolling process is constantly monitored, so that the rolling process by variable speed profiles for both the advance of the guide carriage 34, 36 and the carriage 56, 58 can be optimized.

By connected via the bridge structure 18 supporting legs 10, 12 an extremely rigid machine construction is ensured, the mineral casting substructure 8 and the mineral cast-filled support body 20, 22 cause a much better attenuation than conventional constructions. The cast mineral substructure makes it possible to integrate all the supply elements, with virtually no additional processing required after casting the substructure.

The vertical orientation of the rolling rods 2, 4 greatly simplifies the removal of coolant from the solution disclosed in the applicant's brochure.

Of course, other suitable drives, such as ball screw drives, rack drives or hydraulic drives can be used instead of said planetary spindle drives. The substructure may be formed in a conventional manner by a welded or cast construction in deviation from the above-described embodiment.

The adjustability of the guide carriages 38, 40 also makes it possible to perform a division correction during the rolling process, so that the rolling quality compared to conventional solutions with rolling rods considerably is improved. Instead of the described sliding guide, it is also possible alternatively to use conventional, non-plastic-coated sliding guides, roller guides, for example roller shoes or flat cage guides, which, however, are less favorable than the molded guideways both in terms of load capacities and costs.

In the above-described embodiment, the workpiece is driven by engagement with the rolling rods 2, 4. In an alternative variant, the workpiece can be assigned its own rotary drive, which is synchronized with the NC drives 64, 66 of the rolling rods, so that the stroke of the rolling rods 2, 4 is synchronized with the rotation of the workpiece to be rolled.

The forming forces can be reduced when the rolled portion of the workpiece is subjected to ultrasound. For this Ultraschallbeaufschlagung a suitable ultrasonic head can be integrated into the cold rolling machine. Another possibility is to superimpose the rotational movement of the workpiece during the rolling process with ultrasonic vibrations. This could for example take place in that the above-described rotary drive for the workpiece generates a rotational movement which is superimposed with high-frequency ultrasonic vibrations of low amplitude. By influencing the vibration of the forming process, the forming forces can be reduced during the rolling process, so that an increase in the process speed is made possible. Due to the reduction in the flow limit, materials that are difficult to form can also be cold-rolled using conventional methods.

Disclosed is a cold rolling machine, in which the rolling rods are preferably arranged in the vertical direction and are adjustable via a feed device during the rolling process in the radial direction with respect to the workpiece to be machined.

LIST OF REFERENCE NUMBERS

1

Cold Rolling Machine

2, 4

rolling bar

6

headstock

7

switch cabinet

8th

substructure

10, 12

support legs

14

Horizontal support surface

16

Vertical support surface

18

bridge construction

20, 22

support body

24

Cast supporting structure

26

rear cross-strap

28

front cross strap

30, 32

recesses

34, 36

inclined guides

38, 40

guide carriage

42

counter-guide

44

NC drive

46

spindle nut

48

planetary spindle

50

servomotor

52, 54

guides

56, 58

carriage

60

clamping bodies

62

console

64, 66

NC drives

68

toothed belt

70

profiling

72

ramp

Claims (21)

1. Rolling rack for the non-cutting cold forming of profiles by cold rolling, in particular, for the manufacture of serrations, characterized by a profiling (70) which extends with a constant profile substantially over the entire operative surface of the rolling rack (2, 4).
2. Rolling rack in accordance with claim 1, characterized in that a profile depth (S) is substantially constant along an area (T).
3. Rolling rack in accordance with claim 1 or 2, characterized in that calibrating zones are formed at end portions.
4. Rolling rack in accordance with any one of the preceding claims, characterized in that stress relieving zones are formed at end portions.
5. Rolling rack in accordance with claim 3 or 4, characterized in that the calibrating/stress relieving zones are formed by ramps (72).
6. Rolling rack in accordance with any one of the preceding claims, characterized in that ramps (72) with a smaller profile depth are formed at the end portions of the profiling (70).
7. Rolling rack in accordance with claim 6, characterized in that the area (T) extending between the ramps (72) is formed substantially with a constant profile depth.
8. Rolling rack in accordance with claim 6 or 7, characterized in that the ramps are short ramps (72).
9. Rolling rack in accordance with any one of claims 5 to 8, characterized in that the length (U) of the ramps (72) is considerably smaller than the length (T) with a constant profiling.
10. Rolling rack in accordance with any one of the preceding claims, characterized by manufacture from a hardened and ground cold work steel.
11. Use of rolling racks in accordance with any one of the preceding claims on a cold rolling machine comprising two profiled rolling racks (2, 4) driven in opposite directions, which are each mounted via a slide (56, 58) on a guide (52, 54) and are in engagement with a workpiece rotatably mounted between the rolling racks (2, 4), and comprising a feed device (38, 40; 20, 22) with at least one feed drive (44) via which the rolling racks (2, 4) are adjustable in the direction of engagement during the rolling operation.
12. Use of rolling racks in accordance with claim 11, the feed device having for each guide (52, 54) a guide slide (38, 40) which is displaceably mounted on an oblique guide (34, 36), and the oblique guides (34, 36) associated with the two rolling racks (2, 4) being disposed in the shape of a V in relation to each other.
13. Use of rolling racks in accordance with claim 11 or 12, a feed drive (44), preferably an NC drive, being associated with each guide slide (38, 40).
14. Use of rolling racks in accordance with any one of claims 11 to 13, the free end portions of the guide slides (38, 40) having a bracket (62) on which the drives (64, 66) for the rolling racks (2, 4) are mounted.
15. Use of rolling racks in accordance with any one of claims 11 to 14, the guides (52, 54) for the rolling racks (2, 4) being arranged in a vertical direction or in a horizontal direction.
16. Use of rolling racks in accordance with claim 12, the oblique guides (34, 36) being arranged on two supporting legs (10, 12) of a substructure (8).
17. Use of rolling racks in accordance with claim 16, the two supporting legs (10, 12) being interconnected by transverse joints (26, 28).
18. Use of rolling racks in accordance with any one of claims 11 to 17, a drive which is synchronized with the rolling rack drive being associated with the workpiece.
19. Use of rolling racks in accordance with any one of claims 11 to 18, with an ultrasonic device by means of which the rolled area of the workpiece can be acted upon with vibrations in the ultrasonic range.
20. Method for cold rolling a workpiece which is in operative engagement with two rolling racks (2, 4) drivable in opposite directions in accordance with any one of claims 1 to 10, wherein the rolling racks (2, 4) are adjusted in a radial direction in relation to the workpiece during the rolling operation.
21. Method in accordance with patent claim 20, wherein the predetermined profile depth is formed during a number of successive rolling rack strokes.

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