Method for heating a vehicle wheel

Abstract

The invention relates to a method for heating a vehicle wheel (2), in particular as a preparation for a subsequent shaping method, in which at least a part of the vehicle wheel (2) is heated by means of inductive heating using an inductor (7).

Description

[0001] The present application claims priority from German patent application No. 10 2021 134 233.3.

[0002] The invention relates to a method for heating a vehicle wheel, in particular as preparation for a subsequent forming process.

[0003] Various casting processes for the manufacture of vehicle wheels are known from the general state of the art.

[0004] The vehicle wheels cast using these methods can then be further processed using a technique called flow forming, which involves rolling the wheel rim. Flow forming results in material compaction, leading to increased stability and strength. Furthermore, it saves material, allowing for the production of lighter and more durable vehicle wheels. Another advantage of this well-known method is that multiple wheel widths can be produced from a single cast base, thus reducing manufacturing costs.

[0005] To carry out the flow forming process, the vehicle wheels must be heated to a specific temperature. Currently, this is done in a suitable, usually gas-fired, furnace, which results in very high energy consumption. An additional disadvantage of this method is the use of combustion gases in the heating furnaces, which not only leads to very high costs but also to very high CO2 emissions. Furthermore, problems can arise with certain types of vehicle wheels if specific areas are heated to excessively high temperatures.

[0006] Inductors are known from US 2011 / 206307 A1, KR 101 849 952 B1 and BE 430 219 A, which are used to heat the surfaces of components to an austenitizing temperature and then quench them to harden the surface.

[0007] It is therefore an object of the present invention to provide a method for heating a vehicle wheel, with which the vehicle wheel can be heated in a simple, reliable and environmentally friendly manner.

[0008] According to the invention, this problem is solved by the features mentioned in claim 1.

[0009] The method according to the invention, in which at least part of the vehicle wheel is heated by means of inductive heating using an inductor, offers many advantages compared to the methods used so far.

[0010] Inductive heating generates the required temperature directly within the component itself, rather than in a significantly larger space, resulting in a far lower energy consumption than conventional methods. Furthermore, this also leads to considerably reduced CO₂ emissions and thus a better environmental footprint for the inventive method.

[0011] Another advantage is that the inductor used for inductive heating can be powered by electricity, which, compared to using gas, not only contributes to environmental protection but also offers financial benefits. This financial advantage is further enhanced by the significantly higher efficiency of inductive heating compared to heating in an oven. An additional benefit of using an inductor to heat the vehicle wheel is that the process is simpler.

[0012] Furthermore, there are advantages in terms of space requirements, as an induction device takes up significantly less space than, for example, a gas-powered oven.

[0013] According to the invention, essentially only the rim of the vehicle wheel is heated. This results in even lower energy consumption, since a significantly smaller mass needs to be heated compared to known solutions. Furthermore, the inductor used to carry out the process can have a simpler design and be manufactured more cost-effectively. This embodiment can be particularly advantageous for vehicle wheels manufactured by die casting, as certain areas of the wheel may not be heated excessively.

[0014] In a further advantageous embodiment of the inventive method, if the inductor is arranged inside the rim, this results in more uniform heating of the vehicle wheel. Furthermore, a simpler inductor design is also possible in this case, which in turn can lead to cost reductions. Since the inside of the rim typically has a more uniform contour than the outside, the windings of the inductor can be designed relatively simply. Moving the inductor to position it inside the rim is also simpler than with an inductor (not shown) that is mounted externally on the rim.

[0015] Furthermore, the spokes and / or hub of the vehicle wheel may be cooled. This allows the aforementioned areas of the vehicle wheel, which may not be allowed to overheat, to be kept within the desired temperature ranges.

[0016] A particularly simple way to cool the spokes and / or hub of the vehicle wheel is to apply a cooling medium to the spokes and / or hub during heating.

[0017] According to the invention, the rim is heated for a duration of 20 seconds to 5 minutes, preferably 40 seconds to 3 minutes. Such a duration has proven particularly advantageous with regard to the uniform heating of the areas of the vehicle wheel to be heated.

[0018] In order to carry out the subsequent forming process, in particular the so-called flow forming, in the desired manner, it is provided that the rim is heated to a temperature of 250 to 400 °C, preferably 300 to 360 °C.

[0019] Furthermore, it can be provided that the vehicle wheel and / or the inductor is rotated during heating. This results in very uniform heating of the vehicle wheel and prevents any excessive heat build-up in certain areas, thus ensuring the high quality of the vehicle wheel processed by the inventive method.

[0020] In a further advantageous embodiment of the method according to the invention, if the temperature of at least part of the vehicle wheel is monitored during heating, not only is overheating of the vehicle wheel avoided, but a consistent quality of the same is also ensured.

[0021] A further advantageous embodiment of the method according to the invention can consist of using electricity from renewable energy sources to operate the inductor. This ensures CO2-neutral process execution and thus serves environmental protection.

[0022] The device described below can be used particularly advantageously in the method according to the invention and ensures its simple implementation. Furthermore, the device is simple and inexpensive to manufacture.

[0023] A very advantageous embodiment of a device according to the invention for carrying out the method according to the invention can consist in the inductor being designed as a ring inductor, in particular a multi-winding ring inductor, adapted to an inner area of ​​the rim of the vehicle wheel. Such a multi-winding ring inductor ensures uniform heating of the entire rim of the vehicle wheel and can have a relatively simple construction and thus be more cost-effective to manufacture.

[0024] Furthermore, the device can include a mechanism for supplying a cooling medium to the spokes and / or hub of the vehicle wheel. This allows for very simple cooling of the spokes and / or hub of the vehicle wheel in order to maintain these areas at the desired temperatures despite heating.

[0025] A further advantageous embodiment of the device may consist of a mechanism for rotating the vehicle wheel and / or the inductor. Such a mechanism allows for uniform heating of the vehicle wheel.

[0026] In a further advantageous embodiment, if a device for monitoring the temperature of the vehicle wheel is provided, this offers a simple way to avoid possible overheating of the vehicle wheel.

[0027] An exemplary embodiment of the invention is shown below in principle with reference to the drawing.

[0028] It shows: Fig. 1 a very schematic representation of a system used in a method for manufacturing a vehicle wheel, of which a device for heating the vehicle wheel according to the inventive method is a part; Fig. 2 a side view of a device according to the inventive method for heating a vehicle wheel; Fig. 3 a section along line III-III from Fig. 2 ; Fig. 4 a view according to arrow IV from Fig. 2 ; and Fig. 5 a perspective view of the device according to the method according to the invention.

[0029] Fig. 1 The diagram shows, in a very schematic representation, a system 1 for heating a [unclear text] in [unclear text]. Fig. 1The vehicle wheel 2 is also shown only very schematically. Annex 1 includes a casting device 3 for manufacturing the vehicle wheel 2 by casting, a device 4 for heating the vehicle wheel 2, and a forming device 5, in particular for carrying out a flow forming process on the vehicle wheel 2. All of the devices 3, 4, and 5 are shown in Fig. 1 only very schematically indicated.

[0030] Annex 1 also shows a handling device 6, which is only very schematically indicated, with which the vehicle wheels 2 can be transported between the devices 3, 4 and 5. In the present case, the handling device 6 is a multi-axis robot.

[0031] While the casting device 3 and the forming device 5 may be of a known design and therefore the devices and the process steps carried out with them are not described in more detail below, the device 4, with which a method for heating a vehicle wheel can be carried out, will be discussed in more detail below.

[0032] The device 4 for heating the vehicle wheel 2 is in the Figures 2 to 5 shown in different views. The device 4 has an inductor 7 which is at least partially adapted to the shape of the vehicle wheel 2. In the present case, the inductor 7 is a multi-winding ring inductor, the design of which is particularly common in the Figures 3 and 5 This can be seen and will be described in more detail at a later time.

[0033] The representation of Fig. 3The most easily recognizable vehicle wheel 2 has, in a manner known per se, a circumferential rim 2a, a hub 2b forming the central area of ​​the vehicle wheel 2, several spokes 2c connecting the hub 2b to the rim 2a and two rim flanges 2d forming the lateral boundary of the rim 2a.

[0034] The inductor 7 is designed such that essentially only the rim 2a of the vehicle wheel 2 is heated. During the inductive heating process of the vehicle wheel 2 carried out with the inductor 7, the inductor 7 is arranged inside the vehicle wheel 2 in the illustrated embodiment and thus heats the rim 2a from its inner side. For this purpose, the inductor 7 is adapted to the inner area of ​​the rim 2a of the vehicle wheel 2.

[0035] The inductor 7, designed as a multi-winding ring inductor as described above, has several turns 7a arranged within the rim 2a and a turn 7b assigned to the rim flange 2d facing away from the spokes 2c. The diameter of the individual turns 7a can decrease towards the spokes 2c if, as in the present case, the rim 2a has a certain conical shape. The other components of the inductor 7 are not described in detail here, as they are generally known.

[0036] The rim 2a is inductively heated for a duration of 20 s to 5 min, preferably 40 s to 3 min. Furthermore, the temperature to which the vehicle wheel 2 or the rim 2a is inductively heated by means of the inductor 2 is 250 to 400 °C, preferably 300 to 360 °C. The temperature to which the rim 2a is heated can be set by the inverter (not shown) coupled to the inductor 7.

[0037] The temperature of the vehicle wheel 2 can be monitored during heating by means of a device (not shown) for monitoring the temperature of the vehicle wheel 2. This device could be, for example, a thermal imaging camera or a pyrometer.

[0038] The vehicle wheel 2 and / or the inductor 7 can be rotated during heating. For this purpose, the device 4 can include a mechanism (not shown) for rotating the vehicle wheel 2 and / or the inductor 7.

[0039] Furthermore, a device for supplying a cooling medium to the spokes 2c and / or to the hub 2b of the vehicle wheel 2 may be provided in order to cool the spokes 2c and / or the hub 2b of the

[0040] The vehicle wheel 2 is cooled during inductive heating. For example, this device can be designed as a cooling spray. The temperature of the hub 2b and / or the spokes 2c can be adjusted to the desired level using the cooling medium.

[0041] In a known process, eddy currents are induced in the rim 2a of the vehicle wheel 2 by an alternating electromagnetic field of the inductor 7, and these are converted into heat. Due to the good thermal conductivity of the aluminum material, the desired area, in this case the rim 2a, heats up in a relatively short time. The coupling distance between the inductor 7 and the vehicle wheel 2 can be, for example, 2 to 6 mm. Electricity from renewable energy sources is preferably used to operate the inductor 7.

Claims

1. A method for heating a vehicle wheel (2), in particular as preparation for a subsequent forming process, characterized in that essentially only the rim (2a) of the vehicle wheel (2) is heated by means of inductive heating using an inductor (7) for a duration of 20 s to 5 min, preferably 40 s to 3 min to a temperature of 250 to 400°C.

2. The method as claimed in claim 1, characterized in that the inductor (7) is arranged inside the rim (2a).

3. The method as claimed in claim 1 or 2, characterized in that the spokes (2c) and / or the hub (2b) of the vehicle wheel (2) are cooled.

4. The method as claimed in claim 3, characterized in that a cooling medium is applied to the spokes (2c) and / or the hub (2b) during the heating.

5. The method as claimed in one of claims 1 to 4, characterized in that the rim (2a) is heated to a temperature of 300 to 360°C.

6. The method as claimed in one of claims 1 to 5, characterized in that the vehicle wheel (2) and / or the inductor (7) is rotated during the heating.

7. The method as claimed in one of claims 1 to 6, characterized in that electricity from renewable energy sources is used for operating the inductor (7).

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