Patent ID: 12246375

DETAILED DESCRIPTION

A method of producing a vehicle wheel from a light metal material is disclosed herein. A light metal material is introduced in liquid form into a mold cavity of a casting mold. The material may preferably be introduced via a gate region adjoining the mold cavity. A vehicle wheel is then produced using pressurized casting, where the casting mold is tempered to different temperatures in different areas and where the light metal material is in a liquid (i.e., molten) state and is introduced into the mold cavity at a casting piston speed of more than 5 m/s. Preferably, a ratio or modulus between the smallest cross-sectional area of the gate region and the volume of the mold cavity is at least 0.6 mm2/cm3.

In addition to low machine and tool requirements, the disclosed method satisfies the desired wheel construction, aerodynamics, and crash properties for wheels generated thereby. By using pressurized casting instead of low-pressure chill casting or conventional cold-chamber casting, it is possible to implement various lightweight construction optimizations, aerodynamic optimizations, and crash properties optimizations.

Instead of using low-pressure chill casting, with its limited possibilities with respect to casting cross-section and quality of the casting result due to high tool temperatures of over 500° C., using pressurized casting enables process optimization and the generation of vehicle wheel designs with lightweight construction.

Temperature control of the casting mold leads to a very fast and complete filling of the mold cavity, whereby segregation of the liquid light metal material is avoided. This enables a desired temperature level within the mold cavity, so that, in addition to avoiding uneven heating of the casting mold, the associated deformation of the casting chamber is avoided and thus the premature solidification of the molten light metal material in certain areas is prevented. In addition to increasing the service life of the pistons and the casting mold, this also reduces the piston forces.

By using pressurized casting and tempering the casting mold in different areas to different temperatures, the forces that are observed during the casting process are relatively much lower, resulting in low-turbulence or turbulence-free casting of the vehicle wheel. Although the advantages of the cold-chamber casting process for the production of light metal wheels are also maintained in the pressurized casting process, the problems otherwise resulting from the cold-chamber casting process are avoided.

Furthermore, the method allows very small wall thicknesses of up to 1 mm in certain areas of the vehicle wheel and sometimes even less. The possible reduction of wall thicknesses makes it possible to design a vehicle wheel that has significantly better properties than known vehicle wheels with respect to crash behavior. In particular, the vehicle wheel produced with the disclosed method can be optimized for desired crash behavior.

Due to such thin wall thicknesses, the visible side of the vehicle wheel can be designed to be almost completely closed without significantly increasing the weight of the vehicle wheel. This can significantly improve the aerodynamics of the vehicle wheel. Of course, openings, for example for ventilating a vehicle brake, can also be integrated into such a visible side. A structure increasing the strength of the vehicle wheel can be located within such a disc-like design of the visible side. This means that, compared to known solutions, significant improvements can also be achieved in the aerodynamics of the vehicle wheel manufactured using the disclosed method.

The disclosed method also allows for a low draft angle of up to 1 degree or less, which opens up previously unknown stylistic design possibilities for the vehicle wheel. Furthermore, very fine surfaces with a very small radius of 1 mm or less can be generated.

Since the vehicle wheel can be finished in one casting, the machining required after casting is reduced by approximately 80% or more. The reduced post-processing requirements mean that less waste is produced. The disclosed method considerably reduces the casting time and enables a virtually burr-free casting, while also requiring less raw material and energy. Further, the rapid casting and solidification with casting skin means that otherwise necessary artificial aging can be completely or partially eliminated. Vehicle wheels produced with the disclosed method have a low distortion, which also allows the fine gradations required for bright turning.

The lightweight construction achievable with the disclosed method increases the range of motor vehicles equipped with such vehicle wheels, which contributes to a reduction of environmental burdens.

With regard to rapid filling of the mold cavity and the associated uniform solidification of the liquid light metal material, it is particularly advantageous that the molten light metal material is introduced into the mold cavity at a casting piston speed of more than 5 m/s. If the piston speed is lower than 4 m/s, cold flow fronts occur, resulting in partially inhomogeneous or incomplete filling of the mold, and thus the method cannot be properly utilized.

The ratio between the smallest cross-sectional area of the gate region immediately before entry into the mold cavity and the volume of the overall mold cavity, i.e., the volume of the actual mold cavity and the volume of the gate and overflow, ensures that the molten material enters the mold as uniformly as possible and also flows through it in a steady manner. This uniform flow results in an extremely low-turbulence, quasi-laminar or quiescent casting process in which break-up of the casting front and associated spraying or tearing of the casting front are prevented to the extent possible. At the same time, at a suitable speed, this makes it possible to achieve very rapid mold filling. The molten material is therefore not accelerated in this way, which also prevents an unnecessary increase in casting pressure that could otherwise lead to casting defects. The replenishment required for complete filling of the mold is also better ensured in this way.

The ratio between the smallest cross-sectional area of the gate region immediately before entry into the mold cavity and the volume of the overall mold cavity can also be referred to as a modulus, as described in more detail below.

The very short mold filling times of, for example, 40 to 70 ms, preferably 50 to 60 ms, with a maximum flow velocity of the molten material of up to 70 m/s, can ensure a fine microstructure and high strength of the vehicle wheel produced with the disclosed casting mold.

Using the disclosed method for casting the vehicle wheel, it is therefore possible to configure the mold filling and the targeted solidification within the mold cavity in conjunction with the solidification time in such a way that the structural and strength properties of the vehicle wheel are improved.

In some preferred embodiments, if in areas in which the vehicle wheel 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, it is ensured that the melt remains liquid for a sufficiently long time in relatively narrow areas of the mold cavity to prevent premature solidification of the same and that in relatively wide areas of the mold cavity solidification begins within a reasonable amount of time. Overall, this results in uniform solidification of the entire vehicle wheel to be cast.

It may also be provided that 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. This ensures rapid solidification of the melt in the venting area, which prevents the melt from escaping from the casting mold. In addition, this also allows the liquid light metal material to solidify in a compact design, despite venting, even at high casting speeds.

In some preferred embodiments, the ratio or modulus may be at most 1.4 mm2/cm3. By limiting the ratio between the smallest cross-sectional area of the gate region and the volume of the mold cavity, i.e., the modulus, incorrect dimensioning of the gate system is avoided, thus ensuring the cost-effectiveness of using the disclosed method.

In some highly preferred embodiments, the molten material flows through the mold cavity at a velocity of more than 15 m/s. Such a high flow velocity of the molten material within the mold cavity allows for the production of very thin cross-sections, since the filling of the mold is ensured despite the mold having a significantly lower temperature. If the speed of the molten material through the mold cavity is higher than 70 m/s, the casting front may crack and the molten material may start to spray, which may lead to cold flow points and leads to inhomogeneity. The desired speed of the molten material through the mold cavity leads to a certain speed of the piston as mentioned above.

A casting mold for producing a vehicle wheel from a light metal material is also disclosed herein. The casting mold includes mold parts that form a mold cavity for receiving the light metal material in liquid form. The casting mold also includes a gate region which adjoins the mold cavity and via which the liquid material can be fed to the mold cavity to form the vehicle wheel. The casting mold further includes tempering devices that temper different areas to different temperatures. Preferably, a ratio or modulus between the smallest cross-sectional area of the gate region and the volume of the mold cavity is at least 0.6 mm2/cm3.

The disclosed casting mold enables a very simple adjustment of different temperature ranges within the casting mold through the use of the tempering devices, so that the vehicle wheel to be cast can be produced under the optimum conditions in each instance. The casting mold can have a relatively simple design and is always kept at the set temperatures by the tempering devices.

The ratio or modulus between the smallest cross-sectional area of the gate region and the volume of the mold cavity may preferably be most 1.4 mm2/cm3.

Further, to avoid an undesired acceleration of the molten material within the gate region, the cross-sectional area of the gate region, viewed in the main flow direction of the molten material, may also be designed to be constant or to increase.

In some preferred embodiments, the cross-sectional area of the mold cavity, starting from the gate region, is constant or increasing when viewed in the main flow direction of the molten material up to a depth of at least 60% of the total depth of the mold cavity. In this way, a constant velocity of the molten material is ensured in the major part of the mold cavity, whereas an acceleration of the molten material is permitted in the region of the mold cavity remote from the gate region. Such acceleration of the molten material is particularly advantageous in the production of vehicle wheels, since the region remote from the gate region often contains comparatively narrow cross-sections in which there is a risk of premature, unwanted solidification. The acceleration of the molten material permitted in these regions, and thus the higher speed of the same, prevents such unwanted solidification from occurring and results in homogeneous solidification of the entire vehicle wheel.

In some preferred embodiments, the tempering devices are pressurized water circuits, electric heating cartridges, and/or pressurized oil circuits to enable setting of desired temperatures at the transition of the casting mold into the mold cavity.

If the mold parts and/or inserts connected to the mold parts and/or venting elements consist of different materials, the heat outflow and/or heat inflow can be readily controlled.

In some embodiments, the tempering devices are in operative connection with a control device for controlling and/or regulating the temperatures of the tempered areas. In this way, the temperatures of the individual areas of the mold cavity or casting mold can be readily controlled or regulated.

In some embodiments, the casting mold is composed of at least two mold parts movable relative to each other.

In some preferred embodiments, 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. At least one of the mold parts and thus the entire casting mold can thereby be very well tuned with respect to the matching of individual components, since the tuning elements are suitable for compensating tolerances between the individual components of the casting mold. This also allows the casting mold to be used at temperatures other than those for which it was designed, thus significantly reducing costs. The tuning elements can also be made of different materials and can compensate for the different sizes of the components involved depending on the production of the molded part and the heat input of the molded part. In addition to the size compensation, the tuning elements can either insulate the heat or transfer the heat in a targeted manner, so that in addition to the molding production and the molding heat input, the different sizes are compensated and an insulating effect is achieved or heat is transferred. In addition to size compensation, the tuning elements are also capable of absorbing and/or damping the shocks and/or forces introduced.

To prevent the melt from escaping through the venting 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 may be provided in a venting region of the mold cavity of the casting mold.

An apparatus for producing a vehicle wheel that includes the disclosed casting mold is also disclosed herein.

The apparatus, which may, for example, be in the form of a casting machine, can be used particularly advantageously for performing the disclosed method.

To achieve a simple and safe opening and closing of the casting mold, at least one of the mold parts of the casting mold may be movable in the closing direction of the casting mold relative to another mold part. This may be achieved using at least one guide element that is not part of the casting mold. In this way, it is also possible to avoid additional guides within the casting mold and to move the mold parts of the casting mold without such guides. By arranging the guide elements inside the apparatus and not inside the casting mold, the guide elements can be used for the different casting molds, so that considerable cost savings can be achieved. In addition, in this way straightforward casting mold changes, i.e., changes of the mold parts of the casting mold, are facilitated.

In some preferred embodiments, the mold parts are thermally separated from guide elements moving the same. This prevents excessive heating of the guide elements so that they cannot warp and promotes a high degree of accuracy in the movement of the components of the apparatus and the avoidance of disturbances.

In some preferred embodiments, at least two of the mold parts are movable using respective gripping elements in a direction perpendicular to the closing direction. This allows a very fast opening and closing of the casting mold, which can considerably increase the productivity of the apparatus.

A simple and quick connection of the mold parts with the guide and/or gripping elements results when at least one of the mold parts can be connected to the at least one guide element and/or to the gripping elements using a quick-connect system.

To be able to supply and/or operate the tempering devices in an effective manner, respective units for supplying the tempering devices may be integrated into the apparatus.

In some preferred embodiments, at least one vacuum unit is provided for extracting air from the mold cavity. This vacuum unit enables the air to be removed from the mold cavity quickly and easily in order to fill the mold cavity with liquid light metal material.

A vehicle wheel produced using the disclosed method, casting wheel, and/or apparatus is also disclosed herein. This vehicle wheel may have geometries which are not realizable with known processes. For example, substantially thinner or more filigree structures can be produced. For example, a substantially larger number of spokes can be achieved than in known vehicle wheels.

Examples are described below that illustrate embodiments of the casting mold and apparatus.

FIGS.1-9show different views of an apparatus1for producing a vehicle wheel2shown inFIGS.6-9using a pressurized casting method. The vehicle wheel2can be of any size and shape. The vehicle wheel2shown inFIGS.6-9is therefore to be regarded as purely exemplary. A light metal material is used for the pressurized casting of the vehicle wheel2, preferably an aluminum or magnesium material. For this purpose, light metal materials known in the art and suitable for the method described below can be used for the production of the vehicle wheel2.

The apparatus1has a casting mold3, which in the representation ofFIGS.1-3is in a closed position. As shown, the casting mold3has four mold parts, namely a rigid or immobile mold half4, a movable mold half5, an upper slide6, and a lower slide7. The mold parts of the casting mold3can 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 wheel2. The casting mold3can also have more than the four mold parts described and illustrated herein. The movable mold parts, i.e., the movable mold half5, the upper slide6, and the lower slide7, can be brought from the state shown inFIGS.1-3to the states shown inFIGS.4-9by using the respective guide elements described below. All of these guide elements described below are part of the apparatus1and are not part of the casting mold3.

For guiding the movement of the movable mold half5in the closing direction of the casting mold3, marked with the arrow x inFIG.1, and against this closing direction x, several horizontally running guide columns8are used, which are mounted on one side on a movable clamping plate9and on the other side on a rear machine shield10, which forms a counter bearing. By moving the movable clamping plate9, which is also a guide element for the casting mold3, against the closing direction x, the movable mold half5is brought from its position shown inFIG.1to the position shown inFIG.4. When the movable mold half5is moved relative to the rigid mold half4, the upper slide6and the lower slide7are also moved against the closing direction x relative to the rigid mold half4. Drive devices known in the art and not shown herein can be used to drive the movable clamping plate9, which in this case is movably mounted on rails11of apparatus1. The guide columns8form a guide for the movable clamping plate9and absorb the horizontal clamping forces during casting. The rigid mold half4is attached to a fixed clamping plate12which is connected to a casting unit13which serves to introduce the liquid light metal material into a mold cavity14formed between the mold parts of the casting mold3, which in a known manner comprises the negative mold of the vehicle wheel2to be produced. The filling of the mold cavity14with the liquid light metal material takes place in particular from the outer circumference of the mold cavity14. The casting mold3is preferably designed in such a way that spraying of the material is avoided when the liquid light metal material is introduced into the mold cavity14. The liquid light metal material is introduced into the mold cavity14at a relatively low pressure of up to 100 bar or slightly more.

During the actual casting process, the movable clamping plate9and the fixed clamping plate12, on which the movable clamping plate9is supported, also generate the clamping force. For this purpose, the drive elements or devices used to move the movable clamping plate9can, for example, have hydraulic cylinders and/or toggle lever elements or mold closing elements. The casting mold3can be clamped by means of manual, semi-automatic, or fully automatic clamping elements via form fit and/or frictional connection. The fixed clamping plate12can have a mold spraying device (not shown) and/or an integrated pressure medium system.

The upper slide6can be moved from its position shown inFIG.1orFIG.4to the position shown inFIG.6, in which the upper slide6has been moved vertically upwards relative to the movable mold half5using an upper gripping element15. In a similar way the lower slide7can also be moved downwards using a lower gripping element16from its position shown inFIGS.1and4to its position shown inFIG.6relative to the movable mold half5. The gripping elements15and16and the movable clamping plate9can be operated manually, semi-automatically, or fully automatically. The gripping elements15and16also function as guide elements for the casting mold3. The guide elements for moving the mold parts of the casting mold3can also be equipped with a pressure medium in a way not shown.

While in the embodiment shown the upper slide6and the lower slide7are moved in the vertical direction, it would also be possible to separate the casting mold3in the area of the two slides6and7in the vertical direction and thus move the two slides in the horizontal direction. The gripping elements15and16would be left and right gripping elements in such embodiments. Preferably, the two slides6and7are moved using the respective gripping elements15and16in a direction perpendicular to the closing direction x.

In the method for the production of the vehicle wheel2carried out with the apparatus1and the casting mold3, the light metal material is thus introduced in liquid form into the mold cavity14of the casting mold3by the casting unit13. This introduction of the liquid light metal material takes place at a high casting piston speed of more than 5 m/s. This high speed is achieved by a corresponding movement of a piston of the casting unit13(not shown). The vehicle wheel2is produced using pressurized casting, whereby the casting mold3is tempered to different temperatures in different areas. Preferably, in areas in which the vehicle wheel2has a small cross-section the casting mold3is tempered to high temperatures, and in areas in which the vehicle wheel2has a large cross-section the casting mold3is tempered to low temperatures. The temperature control of the casting mold3allows the solidification behavior of the liquid light metal material to be controlled or adjusted, although the vehicle wheel2has very different cross-sections. In addition, an area in which the casting mold3is vented is tempered to a much lower temperature than the other areas of the casting mold3. This area in which the casting mold3is vented will be described in more detail below.

The mold parts of the casting mold3, i.e., the rigid mold half4, the movable mold half5, the upper slide6, and the lower slide7, 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 mold3is tempered.

After the liquid light metal material has solidified, the mold parts are moved apart in the manner described above to open the casting mold3. Ejection of the cast part produced by the method, i.e., the vehicle wheel2, is performed by an ejector unit17which, like the guide columns8, is mounted on the movable clamping plate9and on the rear machine shield10. As shown, the ejector unit17has a hydraulic unit18, which ensures the movement of the ejector unit17in a known manner. After ejection of the vehicle wheel2from the casting mold3, the casting mold3can be moved in the opposite direction, i.e., from the state shown inFIGS.8-9via the state shown inFIGS.6-7and the state shown inFIGS.4-5to the state shown inFIGS.1-3, to produce the next vehicle wheel2by introducing the liquid light metal material into the mold cavity14.

After completion, the represented vehicle wheel2may be connected to a tire (not shown) to be filled with air or another gas. The vehicle wheel2can also consist of several individual parts, which can also be produced using the method described herein.

FIGS.10-12show an exemplary embodiment of the casting mold3, showing the rigid mold half4, the movable mold half5, the upper slide6, and the lower slide7. The upper gripping element15and the lower gripping element16are also shown.FIG.10also shows that the upper slide6and the lower slide7are connected to the upper gripping element15and the lower gripping element16respectively by means of quick-connect elements19and20, which makes it possible to quickly connect the guide elements of the apparatus1with the mold parts of the casting mold3to ensure quick opening and closing of the casting mold3by moving the mold parts relative to each other as described above.

In addition,FIG.10shows that the upper slide6, the lower slide7, and the movable mold half5are thermally separated from the corresponding guide elements, i.e., the upper gripping element15, the lower gripping element16, and the movable clamping plate9. Corresponding insulating elements21are 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 half4and the fixed clamping plate12. This thermal separation of the mold parts from the guide elements prevents unintentional heating of the guide elements, so that the apparatus1is functional in terms of opening and closing of the casting mold3even in the event of temperature changes.

FIG.10also shows several tempering devices that allow the casting mold3to be tempered to different temperatures to enable uniform solidification of the light metal material within the mold cavity14. The tempering devices are preferably pressurized water circuits, of which several holes22are shown inFIG.10, electric heating cartridges23, and pressurized oil circuits, of which several holes24are also shown inFIG.10. If necessary, other heating or cooling elements can also be used as tempering devices.

The tempering devices, i.e., the pressurized water circuits, the electric cartridge heaters23, and/or the pressurized oil circuits are connected to a control device25, also shown inFIG.10, so that the temperatures of the areas that are temperature controlled by the tempering devices can be controlled and/or regulated. The control device25can also be in operative connection with temperature sensors (not shown), which measure the actual temperature of the individual parts of the casting mold3and thus enable the temperature to be set correctly. The control device25is 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 mold3can 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.

The temperature control of the casting mold3can be designed differently for each individual mold and thus for each individual vehicle wheel2to be produced with the casting mold3or the apparatus1.

FIGS.1,4,6, and8show schematically units26, which are used to supply the temperature control units for the temperature control of the casting mold3and which are integrated in the apparatus1. As shown, the units26are shown as being integrated in the rails11. However, the units26can alternately also be located or attached at other positions within the apparatus1.

Furthermore,FIGS.1,4,6, and8show a vacuum unit27, which is used to extract air from mold cavity14. The vacuum unit27, which generates a corresponding vacuum, is also integrated into the apparatus1and is shown as an example in the rails11. The connection of the units26with the tempering devices and the connection of the vacuum unit27with the mold cavity14are not shown in the figures; these connections can be achieved in a variety of known ways.

FIG.11shows a perspective view of a part of the casting mold3, in which the upper slide6, the lower slide7, the movable mold half5, the control device25, and a part of the mold cavity14can be seen. The gripping elements15and16and their connection to the slides6and7is shown inFIG.11. Further,FIG.11shows that at least one of the moldings, as shown the upper slide6and the lower slide7, has several tuning elements28that may be used to match or tune the moldings to each other. As shown, the slides6and7are matched to the rigid mold half4(not shown inFIG.11) via the tuning elements28. This compensates for tolerance deviations that inevitably occur during the manufacture of the individual mold parts. Further, the tuning elements28may be used to adjust the mold parts of the casting mold3to different temperatures acting on the casting mold3. The tuning elements28, which can also be denominated as insert parts, can be made of a different material than the slides6or7in or on which they are arranged.

The tuning elements28, which have variable thicknesses and can also be designed as tuning cylinders if necessary, may be used to tune the casting mold3in such a way that all mold parts of the mold remain closed even under bursting pressure to prevent the liquid light metal material from escaping. In this way, the mold parts of the casting mold3can be adjusted in a way that account for the technological and economic requirements for the production of specific vehicle wheels2. The tuning elements28can also be reworked or exchanged after appropriate testing, so that a secure sealing of the casting mold3is guaranteed.

FIG.12shows a view of another mold part of the casting mold3, namely the rigid mold half4, which has a venting area29adjoining the mold cavity14, through which the air inside the mold cavity14at the start of the casting process can escape. To prevent the liquid light metal material from escaping with the air from the venting area29, the venting area is, as set forth above, tempered to a much lower temperature than the other areas of the casting mold3. In addition, a temperature-controlled or tempered labyrinth-like structure30is provided in the venting area29, which makes it more difficult for the liquid light metal material to escape from the mold cavity14. In addition or as an alternative to the labyrinth-like structure30, the venting area29may also have cross-sectional changes, surface enlargements, or surface reductions and/or deflections. The venting area29or a venting element forming the venting area29can be made of a different material than the other components of the casting mold3. For example, copper materials such as brass or bronze can be used for the venting area29. Venting areas that are the same or similar to the venting area29can also be located at other points in the mold cavity14.

The venting area29, which may also be termed a venting unit, enables a system that causes the liquid light metal material to be contained through its own heat management in conjunction with the geometric design described, so that, depending on the requirements, a connection to the vacuum unit27can be controlled selectively with full cross-section or reduced cross-section via one or more holes31to be able to use short venting distances. In some cases, these venting areas29can also be provided with a vacuum valve connection or can also be used without a subsequent vacuum connection to serve as a complete or partial overflow for the casting mold3.

FIG.12also shows a closed belt or ring32, which is formed by offsetting the planes of the rigid mold half4. In the closed state of the casting mold3the tuning elements28rest against the ring32to guarantee the tightness of the casting mold3. The ring32thus absorbs the forces occurring during casting.

FIG.13shows a further embodiment of the casting mold3for casting the vehicle wheel2. As noted above, the vehicle wheel2is produced by introducing molten material, preferably a light metal material and in particular a cast aluminum alloy, into the mold cavity14of the casting mold3and subsequent solidification of the molten material. Since in the states shown inFIGS.14-18the molten material forming the vehicle wheel2is already inside the mold cavity14of the casting mold3,FIGS.14-18are at the same time to be regarded as sections through the vehicle wheel2. The vehicle wheel2shown inFIGS.14-18is to be regarded as only one of many possible embodiment examples.

The casting mold3further has a gate region33adjacent to the mold cavity14, via which the molten material is fed to the mold cavity14to form the vehicle wheel2. The gate region can also be called ingate region33or deadhead region33.

Here, the ratio between the smallest cross-sectional area of the gate region33and the volume of the mold cavity14is at least 0.6 mm2/cm3. Preferably, this ratio is at most 1.4 mm2/cm3. In principle, the ratio between the smallest cross-sectional area of the gate region33and the volume of the mold cavity14can also be at least 0.7 mm2/cm3and at most 1.5 mm2/cm3, but the above-mentioned values of at least 0.6 mm2/cm3and at most 1.4 mm2/cm3have proven to be more suitable in trials with regard to uniform flow into and through the casting mold3.

The aforementioned relationship between the smallest cross-sectional area of the gate region33and the volume of the mold cavity14can be understood or referred to as a modulus. In the context of the present disclosure, the modulus links an area dimension [mm2], namely the smallest cross-sectional area of the gate region33, to a volume dimension [cm3], namely the volume of the mold cavity14. In this context, the modulus has the dimension of an inverted length. Furthermore, the unit mm2/cm3is equivalent to the unit 1/m.

For example, if the mold cavity14has a volume of 7000 cm3, the modulus can be selected from an interval between 0.6 mm2/cm3and 1.4 mm2/cm3, for example with the value 0.8 mm2/cm3, or the modulus lies within this range. Thus, in the present example, for the design of the smallest cross-sectional area of gate region33, starting from a volume of 7000 cm3times the modulus of 0.8 mm2/cm3results in a cross-sectional area of 5600 mm2as a target. These values represent only an example of a specific embodiment.

Preferably and as described above, the molten material is introduced into the mold cavity14at a casting piston velocity of more than 5 m/s. The direction of the force with which a casting piston (not shown) presses the molten material over the gate region33into the mold cavity14of the casting mold3is indicated by the arrow F inFIG.14. As a result, the molten material flows through the mold cavity14at a velocity of more than 15 m/s, where, with a view to preventing rupture of the casting front, it is preferable if the velocity of the molten material does not exceed 70 m/s in those cross-sections of the mold cavity14which are critical for achieving a satisfactory component. In other words, in certain cross-sections which are not decisive for the quality of the vehicle wheel to be produced, the flow velocity of the molten material may well exceed the 70 m/s mentioned.

InFIG.14, the casting direction or the main flow direction of the molten material is shown by several arrows, some of which are marked with x. The smallest cross-sectional area of the gate region33is measured in a plane perpendicular to the main flow direction x of the molten material. This smallest cross-sectional area of gate region33is shown by the hatching inFIG.15.

Viewed in the main flow direction x of the molten material, the cross-sectional area of the gate region33is preferably constant or increasing. Accordingly, one embodiment of the gate region33may be that, measured in a direction perpendicular to the main flow direction x of the molten material, all cross-sectional planes of the gate region33are approximately equal in size.

Starting from the gate region33, the cross-sectional area of the mold cavity14, viewed in the main flow direction x of the molten material, is preferably made equal or increasing up to a depth of at least 60% of the total depth of the mold cavity14. These constant or increasing cross-sections of the mold cavity14can also be present up to a depth of 80% of the total depth of the mold cavity14. Only in the last 20-40% of the area of the mold cavity14facing away from the gate region33can the cross-sectional area of the mold cavity14thus decrease.

For all of the above conditions, the mold cavity14and thus the vehicle wheel2produced with the casting mold3can be adapted to specific requirements or conditions.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention disclosed herein. Although the various inventive aspects are disclosed in the context of one or more illustrated embodiments, implementations, and examples, it should be understood by those skilled in the art that the invention extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses of the invention and obvious modifications and equivalents thereof. It should be also understood that the scope of this disclosure includes the various combinations or sub-combinations of the specific features and aspects of the embodiments disclosed herein, such that the various features, modes of implementation, and aspects of the disclosed subject matter may be combined with or substituted for one another. The generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

All references cited are hereby expressly incorporated herein by reference.