Abstract
The invention relates to a method for producing a vehicle wheel from a light-metal material, in which the light-metal material is introduced in liquid form into a mold cavity of a casting mold. The vehicle wheel is produced by means of pressurized casting, wherein the casting mold is temperature-controlled in different regions to different temperatures.
Claims
1. A method of producing a vehicle wheel from a light-metal material comprising introducing a light-metal material in liquid form into a mold cavity of a casting mold, wherein the vehicle wheel is produced using pressurized casting, and wherein the casting mold is tempered to different temperatures in different areas.
2. The method of claim 1, wherein in areas in which the vehicle wheel (2) has a small cross-section, the casting mold is tempered to high temperatures, and in areas in which the vehicle wheel has a large cross-section, the casting mold is tempered to low temperatures.
3. The method of claim 1, wherein the molten light-metal material is in a molten state and is introduced into the mold cavity at a speed of more than 5 m/s.
4. The method of claim 1, wherein a venting area, in which the casting mold is vented, is tempered to a much lower temperature than the other areas of the casting mold.
5. A casting mold for producing a vehicle wheel from a light-metal material comprising mold parts that form a mold cavity for receiving the light-metal material in liquid form, wherein the casting mold has areas tempered to different temperatures using tempering devices.
6. The casting mold of claim 5, wherein the tempering devices are formed as pressurized water circuits, electric heating cartridges, and/or pressurized oil circuits.
7. The casting mold of claim 5, wherein the mold parts and/or inserts connected to the mold parts and/or venting elements comprise different materials.
8. The casting mold of claim 5, wherein the tempering devices are in operative connection with a control device for controlling and/or regulating the temperatures of the tempered areas.
9. The casting mold of claim 5, wherein at least two mold parts movable relative to each other are provided.
10. The casting mold of claim 5, wherein at least one of the mold parts has a plurality of tuning elements for adjusting the mold part to different temperatures acting on the casting mold.
11. The casting mold of claim 5, wherein in a venting area of the mold cavity of the casting mold a surface change in the form of a tempered labyrinth-like structure and/or at least one change in cross-section and/or at least one deflection is provided.
12. An apparatus for producing a vehicle wheel comprising the casting mold of claim 5.
13. The apparatus of claim 12, wherein at least one of the mold parts of the casting mold is movable in the closing direction of the casting mold relative to another mold part by means of at least one guide element not belonging to the casting mold.
14. The apparatus of claim 12, wherein the mold parts are thermally separated from guide elements moving the same.
15. The apparatus of claim 12, wherein at least two of the mold parts are movable by means of respective gripping elements in a direction perpendicular to the closing direction.
16. The apparatus of claim 13, wherein at least one of the mold parts can be connected to the at least one guide element and/or to the gripping elements by means of quick-connection means.
17. The apparatus of claim 12, wherein respective units for supplying the tempering devices are integrated into the apparatus.
18. The apparatus of claim 12, wherein at least one vacuum unit is provided for extracting air from the mold cavity.
Description
[0049] In the following, examples of the embodiments of the invention are shown in principle on the basis of the drawings.
[0050] In the drawings:
[0051] FIG. 1 is a side view of an apparatus according to the invention in a first state;
[0052] FIG. 2 is a view according to arrow II of FIG. 1;
[0053] FIG. 3 is a perspective view of the apparatus of FIG. 1;
[0054] FIG. 4 is a side view of the apparatus of FIG. 1 in a second state;
[0055] FIG. 5 is a perspective view of the apparatus of FIG. 4;
[0056] FIG. 6 is a side view of the apparatus of FIG. 1 in a third state;
[0057] FIG. 7 is a perspective view of the apparatus of FIG. 6;
[0058] FIG. 8 is a side view of the apparatus of FIG. 1 in a fourth state;
[0059] FIG. 9 is a perspective view of the apparatus of FIG. 8;
[0060] FIG. 10 is a casting mold according to the invention;
[0061] FIG. 11 is a further view of a part of the casting mold according to the invention; and
[0062] FIG. 12 is another view of a part of the casting mold according to the invention.
[0063] FIGS. 1 to 9 show different views of an apparatus 1 for producing a vehicle wheel 2 shown in FIGS. 6 to 9 by means of pressurized casting. The vehicle wheel 2 can basically be of any size and shape. The vehicle wheel 2 shown in FIGS. 6 to 9 is therefore to be regarded as purely exemplary. A light-metal material is used for the pressurized casting of the vehicle wheel 2, preferably an aluminum or magnesium material. For this purpose, light-metal materials known per se and suitable for the method described below can be used for the production of the vehicle wheel 2.
[0064] The apparatus 1 has a casting mold 3, which in the representation of FIGS. 1, 2 and 3 is in a closed position. In the present case, the casting mold 3 has four mold parts, namely a rigid or immobile mold half 4, a movable mold half 5, an upper gate or slide 6 and a lower gate or slide 7. The mold parts of the casting mold 3 can be accommodated with or without a zero point system and they can have a very smooth and high-quality surface which does not need to be treated with a coating or the like, or only to a very limited extent, resulting in a very high surface quality of the vehicle wheel 2. Of course, the casting mold 3 can also have more than the four mold parts described and illustrated here. The movable mold parts, i.e. the movable mold half 5, the upper slide 6 and the lower slide 7, can be brought from the state shown in FIGS. 1, 2 and 3 to the states according to FIGS. 4 and 5, 6 and 7 as well as 8 and 9 by means of the respective guide elements described below. All of these guide elements described below are part of the apparatus 1 and do not belong to the casting mold 3.
[0065] For guiding the movement of the movable mold half 5 in the closing direction of the casting mold 3, marked with the arrow x in FIG. 1, and against this closing direction x, several horizontally running guide columns 8 are used, which are mounted on one side on a movable clamping plate 9 and on the other side on a rear machine shield 10, which forms a counter bearing. By moving the movable clamping plate 9, which is also a guide element for the casting mold 3, against the closing direction x, the movable mold half 5 is brought from its position shown in FIG. 1 to the position shown in FIG. 4. When the movable mold half 5 is moved relative to the rigid mold half 4, the upper slide 6 and the lower slide 7 are also moved against the closing direction x relative to the rigid mold half 4. Drive devices known per se and not shown herein can be used to drive the movable clamping plate 9, which in this case is movably mounted on rails 11 of apparatus 1. The guide columns 8 form a guide for the movable clamping plate 9 and absorb the horizontal clamping forces during casting. The rigid mold half 4 is attached to a fixed clamping plate 12 which is connected to a casting unit 13 which serves to introduce the liquid light-metal material into a mold cavity 14 formed between the mold parts of the casting mold 3, which in a manner known per se comprises the negative mold of the vehicle wheel 2 to be produced. The filling of the mold cavity 14 with the liquid light-metal material takes place in particular from the outer circumference of the mold cavity 14. The casting mold 3 is preferably designed in such a way that spraying of the material is avoided when the liquid light-metal material is introduced into the mold cavity 14. The liquid light-metal material is introduced into the mold cavity 14 at a relatively low pressure of up to 100 bar or slightly more.
[0066] During the actual casting process, the movable clamping plate 9 and the fixed clamping plate 12, on which the movable clamping plate 9 is supported, also generate the clamping force. For this purpose, the drive elements or devices used to move the movable clamping plate 9 can have hydraulic cylinders and/or toggle lever elements or mold closing elements, for example. The casting mold 3 can be clamped by means of manual, semi-automatic or fully automatic clamping elements via form fit and/or frictional connection. The fixed clamping plate 12 can have a mold spraying device not shown and/or an integrated pressure medium system.
[0067] The upper slide 6 can be moved from its position shown in FIG. 1 or FIG. 4 to the position shown in FIG. 6, in which the upper slide 6 has been moved vertically upwards relative to the movable mold half 5, by means of an upper gripping element 15. In a similar way the lower slide 7 can also be moved downwards by means of a lower gripping element 16 from its position shown in FIGS. 1 and 4 to its position shown in FIG. 6 relative to the movable mold half 5. The gripping elements 15 and 16 as well as the movable clamping plate 9 can be operated manually, semi-automatically or fully automatically. The two gripping elements 15 and 16 also represent guide elements for the casting mold 3. The guide elements for moving the mold parts of the casting mold 3 can also be equipped with a pressure medium in a way not shown.
[0068] While in the present case the upper slide 6 and the lower slide 7 are moved in the vertical direction, it would also be possible to separate the casting mold 3 in the area of the two slides 6 and 7 in the vertical direction and thus move the two slides in the horizontal direction. The two gripping elements 15 and 16 would be left and right gripping elements in this case. Preferably, the two slides 6 and 7 are moved by means of the respective gripping elements 15 and 16 in a direction perpendicular to the closing direction x.
[0069] In the method for the production of the vehicle wheel 2 carried out with the apparatus 1 and the casting mold 3, the light-metal material is thus introduced in liquid form into the mold cavity 14 of the casting mold 3 by means of the casting unit 13. This introduction of the liquid light-metal material takes place at a high speed of more than 5 m/s. This high speed is achieved by a corresponding movement of a piston of the casting unit 13 not shown. The vehicle wheel 2 is produced by means of pressurized casting, whereby the casting mold 3 is tempered to different temperatures in different areas. This different tempering of casting mold 3 will be described in more detail at a later date using an example. Preferably, in areas in which the vehicle wheel 2 has a small cross-section, the casting mold 3 is tempered to high temperatures and in areas, in which the vehicle wheel 2 has a large cross-section, the casting mold 3 is tempered to low temperatures. The temperature control of the casting mold 3 allows the solidification behavior of the liquid light-metal material to be controlled or adjusted, although the vehicle wheel 2 has very different cross-sections. In addition, an area, in which the casting mold 3 is vented, is tempered to a much lower temperature than the other areas of the casting mold 3. This area, in which the casting mold 3 is vented, will also be described in more detail later.
[0070] The mold parts of the casting mold 3, i.e. the rigid mold half 4, the movable mold half 5, the upper slide 6 and the lower slide 7, can consist entirely or partially of different materials. In particular, the materials of the individual mold parts can be selected depending on the temperatures to be set when the casting mold 3 is tempered.
[0071] After the liquid light-metal material has solidified, the mold parts are moved apart in the manner described above to open the casting mold 3. Ejection of the cast part produced by the method, i.e. the vehicle wheel 2, is carried out by means of an ejector unit 17 which, like the guide columns 8, is mounted on the one hand on the movable clamping plate 9 and on the other hand on the rear machine shield 10. In the present case, the ejector unit 17 has a hydraulic unit 18, which ensures the movement of the ejector unit 17 in a manner known per se. After ejection of the vehicle wheel 2 from the casting mold 3, the casting mold 3 can, in the opposite direction, i.e. from the state according to FIGS. 8 and 9 over the state according to FIGS. 6 and 7, the state according to FIGS. 4 and 5 be brought to the state according to FIGS. 1, 2 and 3, in order to produce the next vehicle wheel 2 by introducing the liquid light-metal material into the mold cavity 14.
[0072] After completion, the represented vehicle wheel 2 can of course be connected to a tire not shown in the drawings to be filled with air or gas. The vehicle wheel 2 can also consist of several individual parts, which can also be produced using the method described herein.
[0073] FIGS. 10, 11 and 12 show an exemplary embodiment of the casting mold 3, showing the rigid mold half 4, the movable mold half 5, the upper slide 6 and the lower slide 7. The upper gripping element 15 and the lower gripping element 16 can also be seen in these figures. FIG. 10 also shows that the upper slide 6 and the lower slide 7 are connected to the upper gripping element 15 and the lower gripping element 16 respectively by means of quick-connection means 19 and 20, by means of which it is possible to quickly connect the guide elements belonging to the apparatus 1 with the mold parts belonging to the casting mold 3 in order to ensure quick opening and closing of the casting mold 3 by moving the mold parts relative to each other as described above.
[0074] In addition, FIG. 10 shows that the upper slide 6, the lower slide 7 and the movable mold half 5 are thermally separated from the corresponding guide elements, i.e. the upper gripping element 15, the lower gripping element 16 and the movable clamping plate 9. Corresponding insulating elements 21 are provided for this purpose, not all of which are visible due to the course of the sectional view and which may also be provided between the rigid mold half 4 and the fixed clamping plate 12. This thermal separation of the mold parts from the guide elements prevents unintentional heating of the guide elements, so that the function of the apparatus 1 with regard to the opening and closing of the casting mold 3 is guaranteed even in the event of temperature changes.
[0075] FIG. 10 also shows several tempering devices by means of which the casting mold 3 can be tempered to different temperatures in order to enable uniform solidification of the light-metal material within the mold cavity 14. The tempering devices are preferably pressurized water circuits, of which several holes 22 are shown in FIG. 10, electric heating cartridges 23 and pressurized oil circuits, of which several holes 24 are also shown in FIG. 10. If necessary, other heating or cooling elements can also be used as tempering devices.
[0076] The tempering devices, i.e. the pressurized water circuits, the electric cartridge heaters 23 and/or the pressurized oil circuits are connected to a control device 25, also shown in FIG. 10, so that the temperatures of the areas temperature controlled by the tempering devices can be controlled and/or regulated. The control device 25 can also be in operative connection with temperature sensors not shown, which measure the actual temperature of the individual parts of the casting mold 3 and thus enable the temperature to be set correctly. The control device 25 is also capable of monitoring the temperatures of the molded part or of the molding zones in addition to other process data and/or geographical data and/or other monitoring information and transmitting them to a higher-level system, for example a machine control system. In this way, the casting mold 3 can be specifically tempered during production and/or for preheating, whereby all influencing parameters, such as different thermal expansions of the components involved, can be monitored and controlled based on the different temperatures and thermal expansion coefficients of the mold parts.
[0077] The temperature control of the casting mold 3 can of course be designed differently for each individual mold and thus for each individual vehicle wheel 2 to be produced with the casting mold 3 or the apparatus 1.
[0078] FIGS. 1, 4, 6 and 8 show very schematically units 26, which are used to supply the temperature control units for the temperature control of the casting mold 3 and which are integrated in the apparatus 1. In the present case, the units 26 are shown as being integrated in the rails 11. However, the units 26 can of course also be located or attached at other positions within the apparatus 1.
[0079] Furthermore, FIGS. 1, 4, 6 and 8 show a vacuum unit 27, which is used to extract air from mold cavity 14. The vacuum unit 27, by means of which a corresponding vacuum is generated, is also integrated in the apparatus 1 and again shown purely as an example in the rails 11. The connection of the units 26 with the tempering devices and the connection of the vacuum unit 27 with the mold cavity 14 are not shown in the figures; they can be carried out in the most varied and familiar ways.
[0080] FIG. 11 shows a perspective view of a part of the casting mold 3, in which the upper slide 6, the lower slide 7, the movable mold half 5, the control device 25 and a part of the mold cavity 14 can be seen. The two gripping elements 15 and 16 as well as their connection to the two slides 6 and 7 can also be clearly seen in FIG. 11. Furthermore, it results from FIG. 11 that at least one of the moldings, in the present case both the upper slide 6 and the lower slide 7, has several tuning elements 28 by means of which the moldings can be matched or tuned to each other. In the present case, the two slides 6 and 7 are matched to the rigid mold half 4 not shown in FIG. 11 by means of the tuning elements 28. In this way, tolerance deviations that inevitably occur during the manufacture of the individual mold parts can be compensated. Furthermore, the tuning elements 28 serve to adjust the mold parts of the casting mold 3 to different temperatures acting on the casting mold 3. The tuning elements 28, which can also be denominated as insert parts, can be made of a different material than the slides 6 or 7 in or on which they are arranged.
[0081] By means of the tuning elements 28, which have the most varied thicknesses and can also be designed as tuning cylinders if necessary, it is possible to tune the casting mold 3 in separating areas between the mold parts of the casting mold 3 in such a way that all mold parts of the mold remain closed even under bursting pressure in order to prevent the liquid light-metal material from escaping. In this way, the mold parts of the casting mold 3 with their temperature zones can be adjusted in such a way that, in addition to the technological and economic requirements that inevitably arise with vehicle wheels 2, the technological and economic design of the casting mold 3 in conjunction with the problems that arise with conventional molds is also taken into account in the production of vehicle wheels 2. The tuning elements 28 can also be reworked or exchanged after appropriate testing, so that a secure sealing of the casting mold 3 is guaranteed.
[0082] FIG. 12 shows a view of another mold part of the casting mold 3, namely the rigid mold half 4, which has a venting area 29 adjoining the mold cavity 14, through which the air inside the mold cavity 14 at the start of the casting process can escape. To prevent the liquid light-metal material from escaping from the venting area 29 in addition to the air, the venting area is, as already mentioned, tempered to a much lower temperature than the other areas of the casting mold 3. In addition, a temperature-controlled or tempered, labyrinth-like structure 30 is provided in the venting area 29, which makes it more difficult for the liquid light-metal material to escape from the mold cavity 14. In addition or as an alternative to the labyrinth-like structure 30, the venting area 29 may also have cross-sectional changes, surface enlargements or surface reductions and/or deflections. The venting area 29 or a venting element forming the venting area 29 can be made of a different material than the other components of the casting mold 3. For example, copper materials such as brass or bronze can be used for the venting area 29. Of course, the same or similar venting areas as the venting area 29 can also be located at other points in the mold cavity 14.
[0083] The venting area 29, which can also be denominated as a venting unit, enables a system that brakes the liquid light-metal material in itself through its own heat management in conjunction with the geometric design described, so that, depending on the requirements, a connection to the vacuum unit 27 can be controlled selectively with full cross-section or reduced cross-section via one or more holes 31 in order to be able to realize short venting distances. In some cases, these venting areas 29 can also be provided with a vacuum valve connection or can also be used without a subsequent vacuum connection in order to serve as a complete or partial overflow for the casting mold 3.
[0084] FIG. 12 also shows a closed belt or ring 32, which is formed by offsetting the planes of the rigid mold half 4. In the closed state of the casting mold 3 the tuning elements 28 rest against the ring 32 in order to guarantee the tightness of the casting mold 3. The ring 32 thus absorbs the forces occurring during casting.
