DE3028956A1 - METHOD FOR PRODUCING ROUND BODIES - Google Patents

Description

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Process for the production of round bodies

The invention relates to a method for the production of round bodies, e.g. wheel rims for motor vehicles, wherein the rim in particular made of an aluminum alloy as a stretched extruded profile with a final cross-sectional shape, rounded to the wheel shape and in the transverse joint is connected by a weld.

In the previous processes, heat treatments had to be switched on between the individual deformation processes in order to achieve the To keep the material largely free of tension. Especially with aluminum alloys, cold deformation Recrystallization phenomena occur, which then occur in the event of later stresses, e.g. due to temperature and / or vibrations, as they are unavoidable in motor vehicle rims, to deformation being able to lead. Especially in the manufacture of motor vehicle rims a constant concentricity must be guaranteed. In the previously known processes in which extruded Aluminum profiles were used, these profiles then had to be post-treated or reformed later so that a relatively large amount of scrap resulted, otherwise the known methods were expensive, lengthy and cumbersome, so that they were just not suitable for mass production.

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The object of the invention is to choose the process steps so that and to use known, easy-to-use devices, so that it is possible, especially in mass production, to build production lines according to the new process without any intervening Heat treatments must be introduced, or that stations must be available that rework the profile cause.

The solution to the problem is that the following process steps to get voted:

a) The extrusion provided with addition is on his front end clamped and on a, the finished profile having core form, with too small a diameter compared to the Finished diameter of the wheel rim pre-bent or rounded.

b) After the clamping piece has been cut to length, the pre-bent extruded profile is placed on a finished profile Core shape with too large a diameter compared to the finished diameter of the wheel rim bent or rounded to approx. 36ο degrees.

c) This is followed by a roll bending machine with a core forming roller and counter rollers with the finished profile After the rear end of the circularly curved extruded profile has been determined, it is rolled to the finished diameter or curved.

d) After cutting the Enstückes is the rolling or bending process with the final profile having core role and counter-rollers while for ^{t? esets} / until the extruded profile to the finished diameter

bent and the ends butted together in alignment.

e) After clamping on a core mold provided with the finished profile by means of several outer jaws provided with the finished profile the welding of the transverse joint takes place.

A completely new path is broken through these procedural steps. It is inevitable that when cold working the profile is deformed, and stresses also occur due to the cold deformation. According to the invention the devices but chosen so that one uses an extrusion profile with excess length, i.e. with an allowance, than it the development of the rim would require, and these are deforming and stress-absorbing pieces through the appropriate choice of procedural steps and Devices chosen so that they are at the beginning and end of the extruded profile and then after the corresponding procedural scripts can be cut to length. So in the first two procedural steps a Related to the core shape around which the extruded profile is bent, while the following step is then scrolling, i.e. using a device that is suitable for scrolling suitable.

Also, during the welding of the cross joint, the procedure is such that stresses are avoided, by making, clamped in a particular order, as indicated in the claims _f and optionally a core mold with the measure related

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The welding process is followed by a calibration process instead of, -, 'although in the claims here the most varied of possibilities are specified.

The workflow is then designed in such a way that first on a core stretching bending device the clamping of the straight Rim profile is done with excessively long, the rim profile the finished profile is already there.

Pre-bending or rounding then takes place on a smaller core shape. This small undersize is required to achieve a to compensate for the springback occurring after this pre-bending. After the springing up, the radius of the rim is made to measure reached, i.e. the smaller core shape takes this spring back into account.

The clamping piece is then cut to length, through which pre-bending was possible; this clamping piece is unusable because it is badly deformed.

Bending or rounding then takes place on the same device, up to about 36o degrees in relation to the finished diameter XU. large core shape. The whole process of the actual dimension must go through this first preforming process.

After the extruded profile has been prepared in this way, it will then further processed on a core bending device.

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This core roll bender has a very small core forming roll inside and two form rollers outside, which have the finished profile, over an extended end piece, which is already When the straight extruded profile was added, this end-bending part, which acts as a lever, is then rounded to the end Extruded profile brought to the actual radius dimension. When this radius dimension is reached, it is extended End piece cut to length, as it is also unusable again due to its severe deformation. Now that happens Bend or round to 36o degrees again with a very small core forming roller and two forming rollers. It's getting close to now the dimensional accuracy of the rim is achieved in an almost tension-free state.

The rim is then completed by the subsequent welding process of the transverse joint. One is even Some thinning of the profile takes place, and in order to take this thinning into account, the core shape on which the rim is at Welding process is stretched, a small oversized dimension. The tensioning process on this core form takes place in a certain chronological order, otherwise there will be a build-up of tension fields on the circumference of the rim or even upsets that noticeable after opening of the welding mold due to ovality do. The most expedient order is in the claims specified for this clamping process. Various welding processes can be used, e.g. inert gas welding with tungsten-inert gas (TIG) or gas press welding, which takes place under heat and pressure, also electron beam welding or inert gas welding metal-inert gas (MIG),

furthermore cold press welding.

It is also essential that the weld seam shells have an exact, unchanged dimension compared to the profile cross-section, when the subsequent calibration process takes place. However, depending on the way in which the welding process proceeds, it would also be conceivable to dispense with the calibration process to be able to. If minor roundnesses are caused by residual stress fields from the weld joint, with minor excessively clean is equalized so that there are no more visible transitions, these small deviations in the profile width can occur both ends, caused by the form fit, in the rolling process be brought to the exact size. In this calibration process, the core forming roller is slightly overdimensioned the nominal dimension (caused by thinning the profile). This calibration is carried out with one or more outer mold rollers, e.g., suitably two outer mold rollers the various options are described in the claims, namely the core is standing, the outer rollers are running, the core is running, Outer rolls are standing (a particularly useful version) or the core is running and outer rolls are running. The rim is here Stretched to the core shape and brought to the final shape and size with several circulations.

Alternatively, it is also possible that the inner roller rotates, The outer shape and rim run between the inner shape and the roller and standing, smooth outer rollers. The rim is in the outer form inserted (clamped) and calibrated with inner form rollers, one or more.

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This will achieve the final shape and size.

An embodiment of the invention is shown in the drawing further features of the invention emerge from the drawing and the description.

Fig. 1 shows the core stretch bending device in the front view, Fig. 2 is the plan view of Fig. 1,

FIG. 3 shows, corresponding to FIG. 2, the process during the pre-bending,

Fig. 4 shows a further phase of this pre-bending,

Fig. 5 shows a ^ further process step on the core stretch bending device ,

Fig. 6 shows another phase of the workflow,

Fig. 7 is a front view of a core roll bending device in the front view;

Fig. 8 is the top view of Fig. 7,

Fig. 9 shows another working phase in the bending process on the core roll bending device,

Fig. 10 shows a further phase of the work process,

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11 shows a calibration device,

Fig. 12 shows schematically the time sequence during tensioning before the welding process.

In the figures, the same numbers indicate the same parts. The letters from a - s show the in chronological order different work processes. The extruded profile 1 is shown in the figures. This extruded profile has that Finished profile of the rim. In the core stretch bending device, a core shape 2 is present, this core shape 2 is from Clamping jaws 5 in the direction of the arrow. 18 moved along by drivers 19, which are located on the turntable 20 of this core stretch bending device are located. This arrangement is important because the clamping jaws both in the direction of arrow 19 and then again when loosening must be moved in the direction of arrow 21, and by this entrainment the profile is spared, there will not be large frictional forces exposed because it is only stressed or deformed by the force transmission at the clamping point. Of course the clamping jaw 5 and the core shape 2 have the finished profile. The straight extruded profile 1 is guided into the device in the direction of arrow 23, with guide profiles 3 being used and mating profiles 4 are present which, when pressed against one another, prevent the finished profile of the extruded profile 1 deformed when it is deformed in the core stretch bender. The profile pieces for the guide profile, counter profile and the clamping jaws are made of an elastic material in order to reduce all deformations to a minimum.

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Of Figure 3 can be seen then, that after loosening the clamping jaws 5, the shim 6 is removed _f since it had to take the work of deformation during the pre-bending or Anrunden. The further operations, which are then shown in Fig. 3 and Fig., Show that the bending now takes place up to about 36o degrees, it is essential that before inserting the curved profile in the direction of arrow 24 in the counter profile 4 edges Must be beveled so that this counter profile is not damaged.

By moving in the direction of arrow 25 and 26, the guide and counter-profiles 3 and 4 are moved towards or away from one another moved to initiate or end the bending process.

The bending piece 6.1, which was present after the clamping piece 6, is now also removed; since it had to take up the additional deformation work again, when it was rounded up to 36o degrees after bending and now in itself the diameter is too large.

Work is then continued on the core roll bending device shown in FIGS. 7 and 8.

On this core roll bending device is then by means of the forming rollers 8 and the core bending roller 9 rounded until the finished diameter is reached. Now the end piece can then 6.1 are cut to length, which in turn had to absorb significant deformation work, as FIG. 8 shows, because this piece To a certain extent, it allows the rounding process to act as a lever.

The turntable 11 also has guide disks 12, the upper and below the extruded profile. 1 are arranged to avoid springing back. These plates are shown in FIG. 7 or 8 not shown in detail.

In Figs. 9 and 10, the core roll bending process is one shown at a different point in time, namely, as FIG. 10 shows, when the weld joint has already formed because the finished size has been reached. In the exemplary embodiment, there are two forming rollers 8, by moving them in the direction of the arrow 27 in one direction or the other, the contact pressure can be increased or decreased, depending on the desired Diameter.

In Fig. 10, the finished size is then reached. Then on a mandrel with oversize, like the Fig. 11 shows, rounded so much, or shaped by the forming rollers, that - as shown in Fig. 12 - the welding process can take place. Here it is essential that the rim to be welded is only opposite the weld seam 13 by pressing jaws is attached to the mold core 28, then the two clamping points 16 are closed, and finally the two clamping points 17. It can be seen that the clamping points 15, 16 are on the side of the rim opposite the transverse joint 13, while the clamping points 17 are adjacent. The clamping points 17 are closer to the center line than the clamping points 16.

It is of course possible to produce a rim from several pieces instead of from one piece, in which case accordingly more weld seams would result.

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It is always important that the inventive idea is realized in the present method, namely to connect a roll bending device on a bending stretch apparatus, in which these two stations can be reversed of course if that requires the work piece or the profile. It is only essential that the deformation work in the case of deformations in this extruded profile through the management of the process steps only affects the end pieces, these can be easily removed, and it is much cheaper to have waste on extruded profiles than laborious process steps such as stress relief annealing , Heat treatments and cumbersome reworking.

Claims (12)

3028955 DR.-ING. G. RIEBLING DR.-ING. P. RIEBLING Dipl.-Ing., Ing. (Grad.). Dipl.-Ing. Authorized representative at the European Patent Office Professional Representatives belore European Pafenl Ol'ice Mandalaires agrees pres! Office european des Luevets Please repeat in the answer L J Your sign your Nachnrhi from D-8990 Lindau (Bodensee) Rnnneiie IO Posllach 3160 July 29, 198o Subject: <? W // A O HG Applicant: Company Späth / -t 776o Radolfzell, Friedrich-Weber-Str. 32 Claims before 1 ^ / Process for the production of round bodies / e.g. wheel rims For Kfz., The rim in particular made of an aluminum alloy as a stretched extruded profile with a final Cross-sectional shape made rounded to the wheel shape and connected in the transverse joint by a weld, characterized by the following process steps: a) the extrusion provided with addition is on his front end clamped and on a core form having the finished profile with too small a diameter opposite Pre-bent or rounded to the finished diameter of the wheel rim, Telephone: Telegram address Bank accounts: Poslscheckkonin Lindau (08382) 6917 054374 (pat-d) patri-lindau Bayer Vereinsbank Lindau (B) Nr 1? 0B578 (BLZ 7352ΟΟ7Ί) Munchnn 'Wi'i W) ¹ ) Hypo-Bank Lindau (B) No. 66/0 2/8920 IBLZ 73520642) Volksbank Lindau (B) No. 51 720000 (BLZ 73590120) 3C28956 b) after the clamping piece has been cut to length, the pre-bent extruded profile is placed on a finished profile Core shape with too large a diameter compared to the finished diameter of the wheel fig bent or rounded to approx. 36o degrees, c) then on a roll bending machine with a core forming roller having the finished profile and counter rollers after the rear end of the circularly curved extruded profile has been determined, it is rolled to the finished diameter or curved, d) after the end piece has been cut to length, the rolling or bending process is carried out continued with a core roll having the finished profile and counter rolls until the extruded profile bent to the finished diameter and the ends flush together, e) after clamping on one provided with the finished profile Core shape by means of several outer jaws provided with a finished profile, the welding of the transverse joint takes place. 2. The method according to claim 1, characterized in that the clamping of the extruded profile before welding takes place at a first step opposite the transverse joint _/ then two clamping points are closed at the same distance on the side opposite the transverse joint and finally two clamping points are closed at the same distance adjacent to the transverse joint. -3- 3. The method according to claim 2, characterized marked that the one used for the welding Core shape has an excess corresponding to the degree of thinning of the profile. 4. The method according to claims 2 and 3, characterized characterized in that the weld seam shells have an exact, unchanged dimension compared to the profile cross-section own. 5. The method according to claims 1-4, characterized in that a calibration process by means of a profiled core forming roller with a slight excess compared to the finished profile takes place in such a way that one or several profiled outer form rollers press the welded rim against the core form roller. 6. The method according to claim 1 and 5, characterized characterized in that the core forming roller is stationary and the outer rollers rotate. 7. The method according to claim 1 and 5, characterized in that the core forming roller rotates and the outer rollers rotate in a standing position. 8. The method according to claim 1 and 5, characterized it indicates that the core forming roller and the outer rollers rotate. 9. The method according to claims 1 and 5 to 8, characterized in that the rim is clamped onto the rotating, profiled core form roller and pressing against the standing outer mold rolls during the rolling process in one or more revolutions on the final molding dimension is brought. 10. The method according to Claimi and 5 to 8, characterized characterized in that the core forming rollers move around the circumference. 11. The method according to claim 1 and 5, characterized characterized in that the rim is profiled into a The outer shape is clamped and with profiled inner shape rollers in one or more revolutions to the final shape is brought. 12. The method according to claims 1 and 5 and 11, characterized in that a profiled Inner roller rotates the profiled outer shape with the rim, whereby the outer shape and the rim run between the inner shape roller and standing, smooth outer rollers.