EP3083099A1

EP3083099A1 - Process and device for producing hot-formed wheel naves

Info

Publication number: EP3083099A1
Application number: EP14821064.4A
Authority: EP
Inventors: Arndt MARX; Christian Müller; David Pieronek; Axel GRÜNEKLEE; Markus ZÖRNACK
Original assignee: ThyssenKrupp Steel Europe AG; ThyssenKrupp System Engineering GmbH; ThyssenKrupp Industrial Solutions AG
Current assignee: ThyssenKrupp Steel Europe AG; ThyssenKrupp AG; ThyssenKrupp System Engineering GmbH
Priority date: 2013-12-17
Filing date: 2014-12-15
Publication date: 2016-10-26
Also published as: US10092944B2; CN106061643A; CN106061643B; WO2015090552A1; KR20160101077A; DE102013114245B3; US20160318091A1; JP2017507781A; CA2940676A1; CA2940676C; JP6725418B2; MX2016007442A

Abstract

The invention relates to a process and a device for producing a wheel nave (1) of a vehicle wheel, in which the wheel nave (1) is produced from a sheet (6) of steel by hot forming, the sheet (6) is at least partially hardened, preferably press-hardened, during or after the hot forming, wherein the sheet (6) is hot-formed by using at least one punch (7) and at least one die plate (8), and at least one opening (3, 4, 5) is introduced into the sheet (6) using hot trimming means (9, 10). The object of providing a process for producing a wheel nave (1) of a vehicle wheel with which a wheel nave (1) can be produced in a simple manner with high precision in such a way as to achieve a further weight reduction and meet the expected geometrical and safety requirements for the wheel nave (1) is achieved in a process and a device for producing a wheel nave (1) of a vehicle wheel by at least one opening (3, 4, 5) being introduced in the hot trimming by using at least one trimming pin (9) and a shutdown pin (10), wherein the shutdown pin (10) has at least one region (10a) with a cross-sectional shape that is variable in the longitudinal direction of the shutdown pin (10) and the at least one opening (3, 4, 5) is calibrated over the variable cross-sectional shape by using the shutdown pin (10).

Description

Method and device for producing hot-formed wheeled dishes

The invention relates to a method for producing a wheel disc of a

Vehicle wheel, in which the wheel disc is made from a steel sheet by hot forming, the board during or after

Hot working is at least partially cured, preferably press-hardened, wherein the board using at least one stamp and

at least one die is hot worked and using

Hot cutting agents at least one opening is introduced into the board.

In addition, the invention relates to an apparatus for producing a wheel disc from a steel board, wherein the device for carrying out a

Hot stamping of the board is suitable for wheel disc, at least one stamp and at least one die for the hot forming and means are provided for performing a hot cut for introducing at least one opening in the board.

The wheels of a motor vehicle are safety components and therefore must be able to withstand the high mechanical cyclical stresses during operation. Conventional steel wheels consist of a wheel disc, which ensures the connection to the wheel hub and a rim tape, which receives the tire.

Wheeled dishes are nowadays manufactured on cold presses with up to eleven stages on cold presses. Almost exclusively cold-formable microalloyed dual-phase steels with a strength of 400 to 600 MPa are used. In addition to the life of the steel wheels, the weight plays an essential role, which in particular on the material costs, the unsprung masses, rotational inertia and thus affect the fuel consumption. In principle, materials with higher strength, for example higher vibration resistance, can be used. However, with increasing strength of the steel materials, the formability of the material generally decreases, so that at

CONFIRMATION COPY cold-forming materials the lightweight potential is considered exhausted. Through the use of hot forming, it is possible to meet the requirements for a high formability at the same time very high strength and dimensional stability of the resulting components. In hot forming, blanks are preferably heated to a temperature at which the forming behavior improves significantly. For example, in the structural transformation into an austenitic structure, a significant improvement of the transformation is achieved. For this purpose, the boards must be heated to a temperature above the Aa temperature point, which depends on steel composition. Due to the greater formability of the material during hot forming, especially when the steel material has austenitic structure, a significant

Reduction of necessary in the cold forming number of forming steps can be achieved. As many forming or process steps as possible are shifted into the tool so that follow-up operations can be omitted. The problem, however, is that in the production of Radschüsseln various perforations must be provided, which can not be introduced into the board before hot forming. So far, these must be introduced after the annealing of the components, which, however, can be done only by laser cutting at material thicknesses of, for example, more than 3 mm. In general, the openings in the wheel disc, for example in wheel bolt holes, have a high dimensional stability, so that these holes can not be introduced before hot working. In addition, a standardized geometry for receiving the wheel bolts is required. The introduction of the holes in the wheel dish after the

Hot forming is associated with considerable effort. This applies, for example, to a subsequent laser cutting of the holes or because of the enormous

Wear for a subsequent, mechanical trimming.

Published patent application DE 103 23 833 A1, which is assigned to the Applicant, discloses the production of a wheel disc from a tempering steel, for example a manganese-boron steel grade 22MnB5, by hot forming. The preparation of a hardened at least partially sheet metal component of a sheet metal blank with At least one opening with projecting collar is also known from German patent application DE 10 2011 117 066 AI.

Proceeding from this, the present invention has the object to provide a method for producing a wheel disc of a vehicle wheel, with which on the one hand a wheel well in a simple manner, can be made high precision, so that the wheel disc meets a further weight reduction and the required geometries and safety requirements. Moreover, it is an object of the present invention to propose an apparatus for carrying out the method according to the invention.

According to a first teaching of the present invention, the stated object is achieved in a method for producing a wheel disc of a vehicle wheel, characterized in that at least one opening using at least one

The Absetzbolzen at least one region having a variable in the longitudinal direction of the Abstellbolzen cross-sectional shape and is calibrated using the Abstellbolzens the at least one opening on the variable cross-sectional shape.

It has been found that in the hot forming and the trimming of the board for introducing openings in the hot formed wheel bowl brings a significant reduction in tool wear during hot trimming with it, so that a mechanical trimming the wheel is possible at low cost and effort. In addition, by means of a setting bolt with an at least partially variable cross-sectional shape, a calibration of the introduced openings can take place immediately after the trimming. Again, it can be exploited that the calibration is still in a warm state, ie at high temperatures, for example at temperatures above Ms starting point, which is dependent on the steel composition, takes place and requires lower forces. Using the parking bolt can in the opening areas Massive transformations and calibration occur simultaneously. Under a massive deformation, for example, a compression or forging understood. The fact that the sheet thicknesses of the output boards are for example in the range of 1 mm to 7 mm, preferably in the range of 2 mm to 5 mm, further weight savings can be achieved. Lower sheet thicknesses can be achieved by choosing a material with higher strength. In particular, when using manganese-boron steels, so-called tempered steels, it is possible by hot forming at the same time to achieve at least a partial hardening or press hardening, so that the finished wheel bowl has the highest strength at low weight. Preferably, the hot trimming and the hot forming is completed before the actual press hardening. According to a first embodiment of the method according to the invention wheel stud holes, ventilation holes of the wheel and / or the wheel hub opening are introduced in the hot cut using at least one trimming pin and at least one Abstellbolzens. All three openings must be highest

Meet accuracy requirements and must not be susceptible to cracking. With the method according to the invention, the possibility exists in particular the

To subject cut edges of the openings of a massive forming, so that the risk of cracking in the opening area is reduced. In addition, through the

Solid forming particularly smooth opening edges can be achieved without rework. The expense of producing a wheel disc is further reduced by the fact that the hot forming and hot trimming of the board to the wheel disc takes place in one working stroke. In particular, the inventive use of

Blade pin and Abstellbolzen allows the implementation of the method in a single step or stroke. According to a further embodiment of the method according to the invention, at least one hollow Abstellbolzen is used, in which an associated

Dip the trim pin during hot cutting. On the one hand, a particularly wear-resistant cut edge can be provided by the setting bolt. On the other hand, a possibility for removing the Beschnitts is given. In addition, a hollow parking bolt and a correspondingly assigned trim pin allows the coupling of the cut, for example, with the movement of the punch or the die. According to a further embodiment of the method, the cut edges of the openings are at least partially reshaped by massive forming. By an at least partial massive deformation, for example, the required geometries of the wheel bolt holes, which are countersunk cone or spherical, are produced in a simple manner. Corresponding opening edges also reduce the risk of cracking in the opening areas and provide the necessary rigidity in the opening.

If the hot trimming is carried out by cutting the trimming downwards according to a next variant, the gravitational force can be utilized for easy removal of the trimming.

According to a further embodiment, the travel paths of the at least one trimming pin and the at least one Abstellbolzens coupled to the travel of the punch and / or the die, so that simple positive guides in the apparatus for hot forming the board can be used to the travel paths of the trimming pin and the to ensure at least one Abstellbolzens in a simple manner.

Alternatively, for example, at least partially, the travel paths of the at least one trimming pin and the at least one Abstellbolzens be controlled separately from the travel paths of the punch and / or the die. The Control can be done for example hydraulically, pneumatically or servo-electric and thus allows greater flexibility with respect to the timing and the tool position for performing the hot-cutting. Particularly preferred according to a further embodiment of the method, the

to be formed board tailored so that the hot forming with integrated hot trimming to Radschüssel can be performed without the use of hold down. As a result, the forming forces are further reduced during hot forming, since the material feed is minimized during forming.

Finally, according to a further embodiment of the method, a circuit board consisting of a manganese-boron steel, a multi-phase steel or a

multi-layer steel composite material to the wheel bowl hot-formed. Manganese boron steels, as well as other tempering steels, can be press hardened after hot forming so that particularly high strengths are achieved. This also applies to multiphase steels and correspondingly curable or press-hardenable

Steel composites.

According to a further teaching of the present invention, the object indicated by a device for producing a wheel disc is achieved in that at least one trimming pin and at least one associated Abstellbolzen are provided, wherein the Abstellbolzen at least one region having a variable in the longitudinal direction of the Abstellbolzens cross-sectional shape and means are provided for calibrating the openings using the area of variable cross-sectional shape of the Abstellbolzens.

As already stated above, the device provided for the hot forming with the integrated trimming and setting bolt simultaneously performs a hot forming and a trimming of the board or the hot-formed

Radschüssel reached, so that in addition to reduced forming forces at the same time high-precision openings of the wheel can be made. As a means to Calibrating the openings using the variable area

Cross-sectional shape of the Abstellbolzens can be provided, for example, forced guidance, during the closing of the device and the

Retracting the punch in the die a corresponding movement of the

Allow parking bolt.

Preferably, at least one parking bolt is hollow, so that the associated trim pin can dip into the parking bolt. By immersing the trimming pin in the Abstellbolzen the movement of the trimming pin and the Abstellbolzens in the tool can be realized in a simple manner by simple positive guides. In particular, this configuration also provides advantages in terms of performing the hot forming of the board for

Radschüssel and warm cut in a single operation. Thus, for example, the parking bolt provide a high-strength cut edge, since the hollow running Abstellbolzen has, for example, a particularly high rigidity

If at least one trimming pin is arranged in such a way that it dips from above into an assigned setting bolt, the trimming pin generated by the trimming bolt can

Trim the board over the assigned parking bolt from the

Device area are removed. Gravitation in particular can automatically transport the trimming from the device area here.

Finally, on the one hand means for coupled motion control of

Trim pin and Absetzbolzen be provided with the travel of the punch and / or the die or means for separate movement control of

Trim pins, parking bolts, punches and / or dies. The coupled

Motion control, for example via positive guides, improves the

Process reliability through the particularly simple embodiment of

Motion control of trim pins, parking bolts as well as punches and / or dies. On the other hand, the alternative of providing a separate motion control of trim pins, parking pins, punches and / or dies provides a larger Flexibility with regard to the setting of specific work steps during the manufacture of the wheel disc. Thus, the times at which the

For example, trimming bolts can be inserted into the parking bolt or the trimming by the punch can also be controlled separately.

In addition, the invention will be explained in more detail with reference to exemplary embodiments in conjunction with the drawing. The drawing shows in

Fig. 1 is a perspective view of a vehicle wheel of a

Motor vehicle,

2 a wheel dish of a vehicle wheel in front view,

Fig. 3 to Fig. 5 in a schematic sectional view of an embodiment of an apparatus for producing a wheel disc from a

Board at three different times of the process and

Fig. 6 to Fig. 8 in a schematic sectional view of the interaction of

Trim pins and parking bolts while performing the procedure.

In Fig. 1, a typical vehicle wheel is first shown in a schematic view, which is composed of a wheel disc 1 and a rim tape 2. The wheel disc 1 is firmly bonded to the rim tape 2 and transmits the forces of the wheel hub to the rim tape 2.

Fig. 2 shows the wheel disc 1 in a front view. To recognize three different openings, which has the wheel 1. First, the wheel hub opening 3 is centrally provided, which is surrounded by a total of 5 wheel bolt openings 4, which are arranged concentrically. In the outer region of the wheel bowl ventilation holes 5 are then additionally provided, which for ventilation of the brakes necessary. The wheel hub opening 3, the wheel bolt openings 4 and the

Ventilation holes 5 must be extremely precisely introduced into the wheel, since the wheel dish 1 otherwise causes problems with tolerances exceeded during use in the vehicle such as imbalances.

3, 4 and 5 now show the method for producing a wheel disc of a vehicle wheel at three different times, wherein the sake of simplicity, the board 6 is shown only in FIG. 3. The board 6 is heated, for example, to a temperature above the A _c i temperature point of the material and inserted into the device shown in Fig. 3. In this state lies

predominantly austenitic structure, which positively influences the formability. The device comprises a punch 7 and a die 8, with which the circuit board 6 is hot-formed. Hot working is usually done at high temperatures, i. For example, if the board has austenitic structure that ensures the preferred forming conditions.

In Fig. 3, a trim pin 9 and a Abstellbolzen 10 is also shown, the Abstellbolzen 10 is hollow and has a portion 10a, in which the cross-sectional shape of the Abstellbolzens 10 changes. In the course of the method, as shown in Fig. 4, the plunger 7 dips into the openings provided by the die 8, so that, for example, the axle receiving opening 3 of the wheel disc is punched out. The trim pin 9 is in Fig. 4, for example, on the board, does not cut them yet. However, in principle, this time of the cut can be chosen more or less freely. The trimming pin 9 is then inserted into the Abstellbolzen 10 and the board 6, which is not shown in Fig. 4 and Fig. 5, trimmed in the area, so that a wheel bolt opening is formed. In Fig. 5, for example, the trim pin is immersed in the Abstellbolzen. The parking bolt 10 also has an area 10a which has a variable cross-sectional shape. Thus, the cross section of the Abstellbolzens increases vertically downwards in this area. The actual hot trimming during the hot forming of the formed plate 6 is to be explained in more detail in FIGS. FIGS. 6 to 8 show the trimming area 11 from that shown in FIGS. 3 to 5 of the device shown in FIG

enlarged version.

Fig. 6 shows the trim pin 9, the hot-formed board 6 and the

Absetzbolzen 10 from the embodiment of Fig. 3 to Fig. 5. At the time of the method, which is shown in Fig. 6, the trimming pin is arranged on the board 6 and is moved further in the direction of the Abstellbolzens. As shown in Fig. 7, the trimming pin dips, for example, in the Abstellbolzen 10 and transports the trimming by the Abstellbolzen from the transformation area. The trim pin conveys the trimming of the board 6 preferably in the direction of the gravitational force down from the forming area. After this

Trimming the opening, the parking bolt 10 is moved vertically upward, so that the area of variable cross-sectional shape 10a calibrates the opening of the board 6. For example, as shown in FIG. 8, a thickening of the opening region or the formation of a conical or spherical countersinking can take place during the calibration. For example, the edge 6a of the opening area of the board 6 can be thickened. Due to the thickening or smoothing of the surface of the cut edge, the opening experiences a higher strength and resistance to cracking. In addition, other requirements for the rigidity of the wheel by a massive forming, for example, a forging or a stowage over the variable cross-sectional shape of the Abstellbolzens be effected. In addition, the usual areas of the die 8 and the punch 7, respectively, may contribute to massive forming during the calibration of the openings.

Preferably, the board 6 has a thickness of 2 mm to 7 mm, more preferably from 3 mm to 5 mm. For wheeled dishes, which are intended for truck wheels, larger wall thicknesses may be required. With the method principle illustrated in FIGS. 6 to 8, not only the

Wheel bolt holes 4 of the wheel disc 1, but also the central

Hub opening and the ventilation holes of the wheel dish are introduced. As can also be seen in FIGS. 6 to 8, hot working and hot trimming of the blank 6 are preferably carried out in one work step.

Not shown in Figures 3 to 5 and 6 to 8, the means for controlling the travel paths of the trimming pin, the Abstellbolzens or the punch and the die. However, it is easily conceivable that the timing of the cutting or the calibration of the individual opening with a separate control of the travel paths of the trimming pin, the Abstellbolzens or the punch and the die can be chosen very flexible. For particularly simple control of the travel paths of the trimming pin, the Abstellbolzens and the punch and the die and simple coupled drive means, such as forced guides are provided. These are extremely robust and yet can provide very precise travel paths.

Due to the high temperature of the reshaped board, the forming forces during hot forming and hot trimming are relatively low in relation to the subsequent strength of the wheel, for example, in the case of partial press hardening. In this respect, further weight-saving potentials can be realized by the wheel dish produced by the method according to the invention, without sacrificing a relatively simple and cost-effective method of production.

Claims

claims

A method of manufacturing a wheel disc of a vehicle wheel, wherein the wheel disc is made from a steel blank by hot working, at least partially hardening the blank during or after hot working, wherein the blank is hot worked using at least one punch and at least one die Use of hot cutting means at least one opening is introduced into the board, characterized in that

at least one opening is introduced using at least one trimming pin and a Abstellbolzens in the hot cut, wherein the

Set down at least one area with a longitudinal direction of the parking bolt

Abstellbolzen has variable cross-sectional shape and is calibrated using the Abstellbolzens the at least one opening on the variable cross-sectional shape.

Method according to claim 1,

characterized in that

Radbolzenlöcher, ventilation holes of the wheel disc and / or the hub opening is introduced in the hot trimming using at least one trimming pin and at least one Abstellbolzens.

Method according to claim 1 or 2,

characterized in that

the hot forming and hot trimming of the board takes place in one working stroke. Method according to one of claims 1 to 3,

characterized in that

at least one hollow Abstellbolzen is used, in which a

dipped trim pin during hot cutting dips.

Method according to one of claims 1 to 4,

characterized in that

the cut edges of the openings are at least partially reshaped by a massive deformation.

Method according to one of claims 1 to 5,

characterized in that

the hot trimming is done by cutting the trimming down.

Method according to one of claims 1 to 6,

characterized in that

the travel paths of the at least one trimming pin and the at least one Abstellbolzens are coupled to the travel of the punch and / or the die.

Method according to one of claims 1 to 7,

characterized in that

the travel paths of the at least one trimming pin and the at least one Abstellbolzens is controlled separately from the travel paths of the punch and / or the die.

Method according to one of claims 1 to 8,

characterized in that

the board to be reshaped is cut to such an extent that the hot forming with integrated hot trimming to the wheel disc is performed without the use of hold downs. Method according to one of claims 1 to 9,

characterized in that

a board consisting of a manganese-boron steel, a multiphase steel or a multi-layered steel composite material is hot-worked to a wheel-disc.

Device for producing a wheel disc (1) from a circuit board (6), wherein the device is suitable for carrying out hot forming of the circuit board (6) to the wheel disc (1), at least one punch (7) and at least one die (8) for the Hot forming and means (9,10) for

Performing a hot blanking for introducing at least one opening (3,4,5) are provided in the board (6),

characterized in that

at least one trim pin (9) and at least one associated

Abstellbolzen (10) are provided, wherein the Abstellbolzen at least one region (10a) with a longitudinal direction of the Abstellbolzens (10) variable cross-sectional shape and means for calibrating the openings using the region (10a) with a variable cross-sectional shape of

Abstellbolzens (10) are provided.

Device according to claim 11,

characterized in that

at least one parking bolt (10) is hollow, so that the associated trim pin (9) can dip into the parking bolt.

Device according to claim 11 or 12,

characterized in that

Trimming pin (9) and Abstellbolzen (10) for generating the Radbolzenlöcher (4), the vent holes (5) and / or the hub opening (3) are provided.

14. Device according to one of claims 11 to 13,

characterized in that

at least one trim pin (9) is arranged so that it dips from above into an associated parking bolt (10).

15. Device according to one of claims 11 to 14,

characterized in that

Means for coupled movement control of trimming pin (9) and Absetzbolzen (10) with the travel of the punch (7) and / or the die (8) are provided.

16. Device according to one of claims 11 to 15,

characterized in that

the means for separate movement control of trim pin (9), parking pin (10), punch (7) and / or die (8) are provided.