US3672021A

US3672021A - Method of making wheels

Info

Publication number: US3672021A
Application number: US11233A
Authority: US
Inventors: Friedrich Wilhelm Schulte; Manfred Diels; Wilhelm Rosenkranz
Original assignee: Fuchs Otto
Current assignee: Otto Fuchs KG
Priority date: 1969-02-20
Filing date: 1970-02-13
Publication date: 1972-06-27
Anticipated expiration: 1989-06-27
Also published as: SE387554B; NL7001206A; BE746180A; DE1908465C3; FR2031546B1; NL143153B; DE1908465B2; GB1249763A; DE1908465A1; FR2031546A1

Abstract

Wheels, particularly for automotive vehicles, are made by first forming a disk-shaped blank, forging the same into a semifinished wheel having a hub and a wheel disk surrounding the hub and having a peripheral rim provided with a cylindrical circumferential edge face, and then mounting the semi-finished wheel in a machine. The edge face is thereupon engaged with at least one pressure roller and split under application of pressure in direction inwardly of the edge face and towards the hub to obtain two unfinished flanges. The unfinished flanges are rollingly deformed in opposite directions axially of the hub and to the desired configuration to thereby obtain two finished wheel flanges.

Description

United States Patent Schulte et al.

[451 June27,1972

[ METHOD OF MAKING WHEELS [72] Inventors: Friedrich Wilhelm Schulte; Manfred Diels; Wilhelm Rosenkranz, all of Meinerzhagen, Germany 3,205,688 9/1965 Paulton 2 9/l59.01X

3,566,503 3/1971 Pacak ..29/l59 FOREIGN PATENTS OR APPLICATIONS 575,341 4/1958 Italy ..29/l59.0l

Primary Examiner-Charlie T. Moon Assistant Examiner-Victor A. Di Palma Attorney-Michael S. Striker [57] ABSTRACT Wheels, particularly for automotive vehicles, are made by first forming a disk-shaped blank, forging the same into a semifinished wheel having a hub and a wheel disk surrounding the hub and having a peripheral rim provided with a cylindrical circumferential edge face, and then mounting the semifinished wheel in a machine. The edge face is thereupon engaged with at least one pressure roller and split under application of pressure in direction inwardly of the edge face and towards the hub to obtain two unfinished flanges. The unfinished flanges are rollingly deformed in opposite directions axially of the hub and to the desired configuration to thereby obtain two finished wheel flanges.

11 Claims, 10 Drawing Figures PATENTEiJJunzv 1972 3. 672.021

sum 2 BF 3 /n yen tor:

METHOD or MAKING warms BACKGROUND OF THE INVENTION The present invention relates generally to a method of making wheels, and more particularly to a method of making wheels essentially without material-removing steps.

. Many attempts are known to make wheels, particularly for motor vehicles, by a forging process, because forged wheels have a considerably greater strength than ones that are cast. However, the difficulty inherent in all these approaches is the fact that the spaceintermediate the respective wheel flanges is usually required to be pronouncedly profiled in cross section, and that this can be obtained only stepwise forgingof the wheelin several different dies. Furthermore, the dies used for this purpose must be of several parts and provided with concentrically adjustable inserts, so that this approach to the manufacture of wheels namely by aforging-process without recourse to a material-removing process-heretofore was possible'only with exceptionally high labor and cost'expenditures.

A further 'difficulty isthat in recent times-and this is particularly true of motor vehicle wheels of light metal, such as aluminum and the like--much higher strength and greater dimensional accuracy is required,-with the-wheel disk being.

required to be provided at one or both axial sides with projections or reinforcingribs which extends from its general plane in order to obtain greatest possible strength and deformation resistance between hub and wheel'flange. at lightest possible weight. These additional requirements of course further complicate and make more difficult the desired production of completely one-piece 1 wheels without recourse to materialremoving steps. 1

Consequently, heretofore the only forging methods known for the manufacture'of motor vehicle wheels have been exceedingly expensive, requiring that after the forging the space between the wheel flanges be reworked with a profile roller. It is known to manufacture simple rope pulleys by making a flat disk'and to split the rim of this disk with a splitting roller in radially inward direction, then to use a form roller to increase the aperture angleof the'split, and finally to use a profile roller of desired width to obtain the required flange profile. However, this approach has been found practical only for simple rope pulleys and cannot be used for the manufacture of wheels where the space between thewheel flanges must be capable of being given variously configurated cross-sectional contours, is relatively wide in axial direction of the wheel, and of irregular contour with the wall section being reinforced at certain locations. This latter feature 'is particularly required in the manufacture of motor vehicle wheels for reinforcing the wheel flanges ifthe weight'advantage of light metals over steel is to be utilized to the fullest. Not only does this result-in a reduction of the vehicle weight, but also and primarily it is intended to relieve the suspension of the vehicle by reducing the suspended wheel mass and to reduce the acceleration and braking forces resulting from the rotational energy at high speeds.

In the aforementioned prior-art method of making simple rope pulleys the circumferential edge face of the planar disk blank was split in the manner outlined before, thereby obtaining a rim of bifurcated cross section whose flanges each have half the thickness of the original disk and which could then be rolled out by using a profile roller. While this approach is not suitable for making vehicle wheels of the type here under discussion, a similar m nufacturing approach has become known by US. Pat. No. 2,075,294 where a blank was formed with thickened rim cross section which was then split by means of a splitting roller, thereby obtaining two. flanges whichwere displaced relative to one another to obtain a rim of flanges. This also was not found entirely satisfactory and another approach based upon the preceding one utilizes a plurality of pressure dies and starts with a preformed blank which is forged and whose rim is already forged so as to have a bifurcated cross section 'in form of two relatively displaced and oppositely projecting radial beads; However, even with these two latter approaches it was possible at best to obtain simple wheel flange configurations of constant wall thickness, and to produce these only on flat or only slightly curved wheel disks without any possibility of providing reinforcing ribs and hubs. The reason is that the profile roller is capable only of bending the existing flanges even if they are so configurated as to adequately be pre-deformed, and the juncture of the flanges with the actual wheel'disk constitutes a particularly critical region with respect to the material characteristics. In other words, it was not posible to obtain a 1 significant material deformation in direction normal to the roller pressure exerted by such a roller without danger that the material becomes warped. It follows from this that it is not possible under'these circumstances to form the wheel flanges with differential wall thickness or cross-sectional dimensions by the use of profile rollers in-accordance with the preceding approaches.

.An additional approach requires a blank which is substantially bowl-shaped and has an outwardly inclined rim, and which is forged to receive a final form in which it is provided with reinforcing ribsand in which of two wheel flanges which are inclined in V-shaped configuration with reference to one another, only one is displaced to an inclined position beyond its original position, whereupon both wheel flanges are pressure rolled to their final configuration. This eliminates the need for predeforming of the wheel flanges.

This latter approach makes it possible to produce a wheel withhub, wheel disk of any desired configuration and wheel flanges of one piece. Wheels of light metal made in accordance with this latter method are particularly Strong. However, the blank is produced in a die under the influence of heat and pressure, and because of the very unequal material distribution at flow paths of different length in the relatively thin wheel flanges, the blank must be very carefully forged to as- I SUMMARY OF THE INVENTION It is, accordingly, an object of the present invention to overcome the aforementioned disadvantages.

More particularly it is an object of the present invention to so simplify in the production of wheels of the type under discussion, the forging process that it is possible to obtain any desired cross-sectional configuration for the space between the flanges directly from the forged blank without any intermediate stages and by the use of pressure deformation.

In pursuance of the above objects, and others which will become apparent hereafter, one feature of the invention resides in a method of making wheels, particularly wheels for automotive vehicles, which method comprises, briefly stated, the steps of forming a disk-shaped blank and forging the same into a semi-finished wheel having a hub and a wheel disk surrounding the hub and having a peripheral rim provided with a cylindrical circumferential edge face. The thus semi-finished wheel is mounted in a spinning machine tool and its edge face is engaged with at least one pressure roller and split under the application of pressure in direction inwardly of the edge face and towards the hub to obtain two unfinished flanges. Thereupon, the unfinished flanges are rollingly deformed in opposite directions axially of the hub and to the desired configuration to thereby obtain two finished wheel flanges. Reinforcing ribs can be provided on the wheel disk at the same time, if desired. The blank to be used in accordance with the present invention is provided with a single die with the necessary wheel dimensions and with a rim cross-sectionwhich is of substantially rectangular configuration-which guarantees the most advantageous material distribution from the point of pressure application and without incorporating any danger of fold and crack formation. The necessary control steps until the forged blank is mounted in a machine tool for further processing are thus significantly simplified. The rim which according to the invention is of substantially rectangular cross-section, as mentioned before, is simply obtained with surprisingly precise manufacturing tolerances by adhering to the predetermined spacing between the halves of the die when the same are pressed together. The customarily necessary removal of the flashing by sawing it off or resorting to material-removal processes, such as milling, produces an even cylindrical circumferential edge face in preparation for the subsequent pressure deformation steps. Advantageously, the planar surfaces which extend normal to the cylindrical circumferential edge face are also smoothed at the same time.

Further preparatory steps are not necessary, and a proper centering will automatically occur when the work piece or blank is mounted tightly enough in the machine tool. It is thus only necessary to provide the customary bores for the mounting screws and for the tire valve, and to finish the surface of the hub bore and/or the abutment surfaces of the finished wheel in the desired and customary manner.

It will be appreciated from what has been said before that the novel method is particularly advantageous for the mass production of motor vehicle wheels. Advantageously the pressure roller or rollers for splitting the rim are moved radially against the cylindrical circumferential edge face and thereupon inwardly thereof to obtain the desired splitting, and simultaneously are also shifted axially with reference to the hub of the wheel so as to increase the width of the gap obtained on splitting. It is particularly advantageous if the pressure rollers used for the splitting step are shifted during their radially inward movement also in axial direction of the hub to such an extent that the aperture angle, the wall thickness and the relative position of the two unfinished flanges obtained as a result of the split all approach the desired values'which it is sought to obtain in the finished wheel. According to a further concept of the invention the method can be further simplified by using the splitting rollers not only for the actual splitting step but also for the subsequent deformation of the unfinished flanges to their finished configuration of the wheel flanges. The rollers are guided in known manner by the use of appropriate templates, and this directly results in the formation of the wheel flanges with desired cross-sectional differentiations.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specified embodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an axial section through a first vehicle wheel;

FIG. 2 is a view similar to FIG. 1 but illustrating a different second vehicle wheel;

FIG. 3 is a fragmentary end-elevational view of FIG. 2, seen in the direction of the arrow III of that Figure;

FIG. 4 is a view analogous to that of FIG. 3 but seen in the direction of the arrow IV in FIG. 2;

FIG. 5 is a fragmentary cross section of the blank which is formed in a die and which constitutes the starting point for the method according to the present invention;

FIG. 6 is a fragmentary cross section on an enlarged scale of the rim of the blank shown in FIG. 5;

FIG. 7 is a view similar to FIG. 6 but showing a first deformation stage in which the rim is split;

FIG. 8 is somewhat diagrammatic cross section of the same rim portion shown in FIG. 6 but illustrating a further defonnation stage subsequent to that shown in FIG. 7;

FIG. 9 is a view analogous to FIG. 8 showing still another deformation stage; and

FIG. 10 is a view analogous to FIG. 9 but showing the final deformation stage.

DESCRIPTION OF THE PREFERRED EMBODIMENTS It is emphasized again, before discussing the drawing in detail, that the method according to the present invention provides for the manufacture of wheels without recourse to material-removing processes for the actual manufacturing operation, and regardless of the particular configuration of the particular wheel disk with hub or with reinforcing ribs. Any desired configuration of the wheel flanges, particularly exteriorly reinforced wheel flanges can be obtained, as well as reinforcements which extend in parallelism with the wheel flanges and serve for a reliable retention and guidance of the tire if the wheel is for motor vehicles. All of this is obtained exclusively by the configuration of the die used in forging the original blank and the particular guidance templated used for guiding the pressure rollers with reference to the blank which is mounted in a machine tool. Different types of metal are suitable, and while light metals such as aluminum and the like are particularly suitable, the particular type of metal involved is basically immaterial. If necessary or desirable the blank may be subjected to intermediate annealing if it is desired to at least partially reverse a hardening of the forged or rolled metal in order to reduce the force required for the defonnation. The

simplest deformation is cold rolling, and the simplest rolling processes requires only s single pressure roller with requisite guidance templates. However, it is naturally advantageous to use the known machine tools utilized generally for this type of rolling and which employs several, particularly three concentrically operating pressure rollers which contact the blank simultaneously or at slightly displaced locations in series.

Keeping this in mind, and discussing firstly FIG. 1, it will be seen that this illustrates a relatively simple wheel 1 with reinforced wheel flanges 11, 11' and cross-sectional reinforcements 12 extending in parallelism therewith which guarantee a reliable retention and guidance of the tire between the wheel flanges l1 and 11. In this embodiment the wheel 1 is assumed to consist of an aluminum alloy and it is produced from a cylindrical cast blank under the influence of heat and pressure to obtain a substantially bowlor plate-shaped blank with thickened rim. Subsequently the non-illustrated blank is formed in a two-part die to the final configuration of a wheel disk 3 of any desired shape with a hub 4 and an annular circumferential rim 5 of substantially rectangular cross section, analogous to the one shown in FIG. 5. The cylindrical circumferential edge face 6 (again see FIG. 5) is then simply split radially by contact with a pressure roller in a machine tool, and the two thus obtained unfinished flanges are axially displaced with reference to the hub 4, and are rolled to the desired final configuration by pressure rollers which are guided in their movements by a guidance template until the desired rim-base configuration 10 (see FIG. 10) is obtained.

A more complicated wheel 2 is shown in FIG. 2 and the individual processing steps of the present method are illustrated and explained in details in FIGS. 3-10 with reference to the wheel shown in FIG. 2. It will be appreciated that the necessary bores and configuration of the hub can be obtained without difiiculty, and do not form a part of the present invention.

The wheel shown in FIG. 2 is identified with reference numeral 2 and illustrated as being again a wheel for a motor vehicle. It is assumed to consist of a light metal, such as aluminum or the like, and is provided with wheel flanges 21 and 21' and reinforcements 22 which are analogous to the wheel flanges ll, 11' and the reinforcements 12 of FIG. 1. The major difference between the wheel of FIG. 2 over that of FIG. 1 is in the very strong deformation-resistant configuration of the wheel disk 23, beginning at the hub 24.

As mentioned before, FIG. 3 is a fragmentary and elevational view as seen in the direction of the arrow HI, whereas FIG. 4 is a similar view but seen from the opposite side of FIG.

2 in the direction of the arrow IV. It is readily evident from FIGS. 3 and 4 that the wheel 2, or more particularly its wheel disk 3, has a very complicated configuration. The details of this configuration will not be further described because they do not form a part of the present invention; they are shown here only to indicate the complexity of shape which it is possible to obtain by resorting to the method according to the present invention, beginning with the formation of the blank in a forging step. It should be parenthetically pointed out that the bore 25 of the hub 24, and the bores 26 for securing the wheel, are produced in conventional manner, and that the contact surfaces 27 (see FIG. 2).are also produced and built in conventional manner.

It is a particular advantage of the wheel shown in FIG. 2 that it is provided with the projecting spoke-like supporting portions 28 intermediate which there are free areas 29 formed by drilling, milling or the like, and of which three are provided altogether. These free spaces 29 are shown in broken lines in FIGS. 3 and 4 to indicate that they can be produced at any time, irrespective and entirely separately from the-present method. It will be appreciated that they are provided not only for the reason that they impart to the wheel an aesthetically pleasing appearance, but also because they provide an improved cooling of the hub area during the braking action and because they significantly reduce the quantity of material incorporated in the wheel 2 and thereby decrease the weight of the wheel and the rotational energy necessary for turning it.

Referring now to FIGS. 5-10 it will be seen that these show the steps according to the present invention by which the forged wheel blank shown in FIG. 5 is converted to the final wheel shown in FIG. 10, or again in FIG. 2. In this connection it is emphasized that the portions 28 do not undergo any changes whatever during the method according to the present invention.

The wheel disk 23 of the blank shown in FIG. 5 which latter has been produced by forging in a die as mentioned before, is clamped between two jigs or jaws of requisite configuration in a machine tool of known type and at this time it is advantageous but not necessary that the material corresponding to the spaces 29 in FIGS. 3 and 4 has already been removed because this facilitates handling of the wheel.

The machine tool is of known construction and those conversant with this art will also be conversant with thetype of machine tool in question. It utilizes one or several pressure rollers, and if there is more than one they are arranged in form of one or more pairs with the rollers of each pair being concentrically with reference to one another. The single or several rollers are guided in known manner by a guidance template. The operation of such pressure rollers controlled by guidance templates is already well known, and is for instance employed in forming cooking pots and utensils of aluminum; it produces clean surfaces of high dimensional accuracy.

In accordance with the prior art the use of such rollers for the production of simple rope pulleys was already known as mentioned before, and the rollers were advanced radially inwardly with reference to the axis of the blank which was to be converted into a pulley. According to the present invention, however, it is now possible to use such rollers in a machine tool of the type under discussion directly for forming from a blank such as that shown in FIG. 5 and having a circumferential outer rim 5 of substantially rectangular cross section, to form the finished configuration shown in FIGS. 2 and 10.

When the blank of FIG. 5 is mounted in the machine tool, one or several pressure rollers 17 are moved into contact with the outer cylindrical circumferential edge face 6 of the rim 5, and then radially inwardly with reference to the axis of the hub 24, to thereby split the rim 5 of FIG. 6 and obtain the configuration of FIG. 7, where two

unfinished flanges

8, 18 are produced which are separated by a substantially V-shaped gap 7. The roller or rollers 17 are advanced not only in radially inward direction towards the axis of the hub 24, but also in axial direction of the hub 24, by template control. Furthermore it has been found that at least during this stage of the operation it is advisable that the roller or rollers 17 be slightly inclined. The roller or rollers are displaced in axial direction of the hub 24 at the same time as they are displaced radially inwardly towards the hub 24, and the axial displacement is to such an extent that the aperture angle, the wall thickness of the

unfinished flanges

8 and 18, and the relative position of the two

unfinished flanges

8 and 18 at least approximate the desired values which are to be obtained in the finished wheel shown in FIGS. 2 and 10.

The next-following intermediate stage is shown in FIG. 8. First, the roller 17 which is diagrammatically illustrated is advanced towards the left of FIG. 8, being inclined at the angle a with respect to the axis of the hub 24. This causes the unfinished flange 8 to be deformed from the full-line configuration to the broken-line configuration which is identified with reference numeral 8. In corresponding manner the unfinished flange 18 is similarly deformed until, it assumes the configuration and position identified in broken lines with reference numeral 18, the second being utilized for this purpose (not illustrated); however, it is also possible to use a single roller 17 and to employ it first to deform one and thereupon other of the flanges.

Once this has been accomplished, the next intermediate stage illustrated in FIG. 9 takes place. Here, a pressure roller 19 is used to deform the unfinished flange 8 from the brokenline position and configuration of FIG. 8 to the fullline position 8a of FIG. 9. Similarly, the flange 18' of FIG. 8 is deformed to the full-line position 18a of FIG. 9 by a second roller 19.

Coming, finally, to FIG. 10, it will be seen that this shows the finished configuration 10 of the space between the finished wheel flanges 21 and 21'. A pressure roller 20 is shown in FIG. 10 corresponding in its configuration substantially to the rollers 19, 19'. It will be seen that in FIG. 20 the reinforcement 22 is illustrated having been produced by the successive steps of FIGS. 7-10. They extend in parallelism with the respective finished wheel flanges 21 and 21'. The wheel flanges 21 and 21' are seen to be rounded, and this is advantageously accomplished by a material-removing process, such as milling, but it is again emphasized that all other forming steps are produced exclusively by template guidance of the roller 17 and/or the rollers l9, l9 and 20.

The mounting of the blank in the jaws or jig of the machine tool remains unchanged throughout the entire deformation process, and the configuration of the jaws or jigs used for the mounting and serving at the radially inner side of the flanges as a support and to counteract the pressures of the

rollers

17, 19, 19' and 20, corresponds to the predetermined dimensions desired to be obtained and which are achieved stagewise and successively by the cold rolling deformation of the metal.

For each individual stage it is possible to use the corresponding formed rollers which are used for producing the configuration shown in FIG. 7 with identical dimensions simultaneously or almost simultaneously concentrically and being guided substantially in radial direction. However, it is also possible to use the same pressure roller, that is a group of identically configurated rollers with a corresponding template guidance for carrying out the various deformation steps. This was illustrated in the drawing by showing that the roller 17 can be used for the deformation illustrated in FIG. 7 as well as for the conversion of the unfinished flange 8 to the configuration 8' in FIG. 8.

For facilitating an understanding of the invention it was decided to show the rollers 19, 19' to be of different configuration from the roller 17, just as the roller 20 differs from both the roller 17 and the rollers 19, 19'. However, it is again emphasized that these

rollers

19, 19 and 20 can be replaced by a single roller 17 of necessarily slender configuration, and which is then not only continuously displaced axially of the hub but also inclined to difierent angles as needed to obtain the difierent material deformation. For static reasons it is advisable to use at least two rollers which act at opposite sides of one and the same unfinished or semi-finished flange, and for stance to the rollers 19 and 19' which are moved in opposite axial directions of the hub 24 away from one another. Of course, details as to which approach is chosen depend largely upon the construction of the wheel which is to be produced and can be readily selected by an operator conversant with the type of machine tool under discussion by controlling the advancement of the respective rollers and by utilizing an appropriate template control. The necessary electrical or electronic controls may be carried out automatically, for instance electronically as just mentioned or via suitable program control. Thus, the method according to the present invention may be largely automated in actual practice, so that a semi-skilled operator can readily and reliably supervise the separation of several of the machine tools at once. None of these advantages would be similarly achievable with the methods known from the prior art which require a succession of different operational stages with multiple-section dies and with the requisite ejector's, transportation devices and control devices.

According to the invention it is also possible to advance the roller or rollers 17 utilized for splitting the rim (see FIG. 7) exclusively in axial direction of the hub of the wheel, if they are inclined at such an angle with reference to the axis of the hub that during the splitting of the rim 5 substantially only one of the thus obtained

unfinished flanges

8, 18 is continuously laterally (that is axially of the hub) deflected. The advantage obtained in this case is that for all intents and purposes sliding friction of the respective roller with reference to the rim 5 occurs.

As already mentioned above, the invention can be practiced with blanks of different metals, including steel. If the metal is a light metal, such as aluminum or the like, the deformation of the material can be eased considerably by heating the same. Such intermediate annealing reverses cold hardening of the material and constitutes a reliable aid in preventing the formation of cracks in the regions of particularly high deformation of the material.

The production of a one-piece wheel, particularly of light metal, in accordance with the present invention will now be explained on hand of the following EXAMPLE A circular cross section ingot of 180 mm diameter is produced in a continuous-casting installation. The material used is the aluiminum alloy designated AlMgSil, which is somewhat analogous to the U.S. alloy 6061 but comprises 0.8% Mg, 1.1% Si, 0.3% Mn, 0.2% Fe, 0.1% Cu, 0.2% Zn, 0.15% Cr and 0.2% Ti. The oxide layer on this ingot is removed by material-removing methods. Thereupon the ingot is subdivided into sections of 150 mm length and each having a weight of 10.3 Kg. The individual sections are heated to a temperature of 450 C. and warm pressed in dies of requisite configuration to obtain a plateor bowl-shaped blank having a thickened rim or edge.

This blank is already forged in the two-part die to the final configuration of the wheel disk 23 with the hub 24, as shown in FIG. 5. Subsequently, it is calibrated in a calibrating or straightening press. Now the areas 29 are removed in a duplicating milling machine to obtain correspondingly configurated empty spaces whereby not only the weight of the wheel is reduced but also the mounting of the wheel for all subsequent forming steps according to the present invention, and also for any material-removing steps is facilitated.

The rim 5 of substantially rectangular cross section with the cylindrical circumferential edge face 6 are milled to the intended diameter, for instance 35 mm thickness and 440 mm outer diameter. The inner bore 25 of the hub 24 and the bores 26 for fastening of the wheel are produced in known manner and the abutment surface 27 shown in FIG. 3 is finished. The

thus-produced semi-finished wheel is carefully examined for material faults, for which purpose the surfaces are pickled so that even small faults can be readily identified and removed.

The semi-finished wheel now has the configuration shown in FIG. 5. It is inserted into a two-part chuck or jig whose jaws are tightly clamped with one another, for which purpose they extend through the respective spaces 29 into engagement. This chuck is a part of a machine tool in which it is rotated. Now the operational steps shown in FIGS. 7-10 are carried out by the radially and axially advanced pressure rollers, such as the

rollers

17, 19, 19' and 20, which deform the material to the final finished configuration shown in FIG. 10. It is advantageous that several rollers concentrically operate and act upon the work piece at one and the same time. If the work piece is heated to a temperature of approximately 250 C, the manufacturing steps may be accelerated and the force required substantially reduced. A set of three pressure rollers 17 is sufficient for carrying out the entire deformation process without having to change the positioning of the wheel with respect to the chuck.

If it is desired to mass produce the wheel in large quantities, the manufacturing time can be significantly reduced if each semi-finished wheel is first subjected to the initial deformation step shown in FIG. 7, and then moved to a second machine tool where the remaining steps of FIGS. 8, 9 and 10 are carried out. In this case it is advantageous that, differing from the aforementioned example, a soft-annealing step at 450 C. with subsequent slow cooling is interposed before the respective wheel is transferred from the first machine tool to the second machine tool; this guarantees that in the second machine tool the

unfinished flanges

8 and 18 can be deformed in cold condition in the manner shown in FIGS. 8-10 without fear of creating cracks or fissures in their material. In fact, if very large quantities of wheels are involved, the steps of FIGS. 8-10 can be further subdivided and if desired each of these steps can be carried out on a separate machine tool. In this case it is advantageous that again the wheel be subjected to annealing each time it is removed from one machine tool and before it is mounted in the next one. By resorting to this approach it is possible to conform the rate of conversion of the semi-finished wheels-that is the rate at which the wheels can be subjected to the steps shown in the FIGS. 8-10-to the rate at which the forging die is capable of producing semi-finished wheels such as the one shown in FIG. 5.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of applications differing from the types described above.

While the invention has been illustrated and described as embodied in a method of making wheels, particularly wheels for automotive vehicles, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claim:

1. A method of making wheels, particularly wheels for automotive vehicles, comprising the steps of forming a diskshaped blank; forging the same to obtain a semi-finished wheel having a hub and a wheel disk surrounding said hub and having a peripheral rim provided with a cylindrical circumferential edge face; mounting said semi-finished wheel in a machine tool; engaging said edge face and splitting said rim under application of pressure by a pressure roller in direction inwardly of said edge face and towards said hub to obtain two unfinished flanges; and then rollingly deforming by said pressure roller said unfinished flanges in opposite directionsaxially of said hub and to the desired configuration by moving said pressure roller axially of said hub, to thereby obtain two finished wheel flanges.

2. A method as defined in claim 1, wherein the step of splitting said rim comprises advancing said pressure roller with reference to said semi-finished wheel in direction inwardly of said edge face towards said hub.

3. A method as defined in claim 1, wherein the step of splitting said rim comprises advancing said pressure roller with reference to said semi-finished wheel in direction inwardly of said edge-face towards said hub as well as in direction axially of said hub.

4. A method as defined in claim 1, wherein advancement of said pressure roller axially of said hub is effected concomitantly with advancement thereof towards said hub. I

5. A method as defined in claim 1; further comprising the concomitant step of rotating said semi-finished wheel abou the axis of said hub.

6. A method as defined in claim 1; further comprising the step of engaging said edge face with at least one additional pressure roller and advancing the same inwardly towards said hub and in opposite axial direction of said hub from said pressure roller.

7. A method as defined in claim 6, wherein said pressure rollers are advanced in opposite axial directions of said hub through distances requisite for imparting to said flanges a relative position, aperture angle and wall thickness approaching the corresponding values desired to be obtained for the finished wheel flanges.

8. A method as defined in claim 1, wherein the step of rollingly deforming said unfinished flanges is efiected by rolling engagement with said pressure roller.

9. A method as defined in claim 6, wherein said pressure rollers are of identical configuration.

10. A method as defined in claim 6, wherein said pressure rollers each have an axis of rotation which is inclined at a predetermined angle with reference to the axis of said hub.

11. A method as defined in claim 10, wherein said axis of rotation of only one of said pressure rollers is inclined with reference to said axis of said hub at an angle requisite for continuously rollingly deforming the associated unfinished flange in response to advancing of said one pressure roller inwardly towards as well as in direction axially of said hub.

Claims

1. A method of making wheels, particularly wheels for automotive vehicles, comprising the steps of forming a disk-shaped blank; forging the same to obtain a semi-finished wheel having a hub and a wheel disk surrounding said hub and having a peripheral rim provided with a cylindrical circumferential edge face; mounting said semi-finished wheel in a machine tool; engaging said edge face and splitting said rim under application of pressure by a pressure roller in direction inwardly of said edge face and towards said hub to obtain two unfinished flanges; and then rollingly deforming by said pressure roller said unfinished flanges in opposite directions axially of said hub and to the desired configuration by moving said pressure roller axially of said hub, to thereby obtain two finished wheel flaNges.

4. A method as defined in claim 1, wherein advancement of said pressure roller axially of said hub is effected concomitantly with advancement thereof towards said hub.

5. A method as defined in claim 1; further comprising the concomitant step of rotating said semi-finished wheel about the axis of said hub.

8. A method as defined in claim 1, wherein the step of rollingly deforming said unfinished flanges is effected by rolling engagement with said pressure roller.