Device for Die Casting a Metal Component

Abstract

A device for die casting a metal component included a die casting mold which has a cavity that forms the component. The cavity is connected to a source for a metal melt by at least one temperature controlled supply channel. The metal melt is introduced into the cavity via at least one casting valve. The supply channel forms an annular channel, in which metal melt can be circulated via a conveying apparatus.

Claims

1. A device for die casting a metal component, comprising: a die casting mold having a cavity that forms the component; at least one temperature controlled supply channel connecting the cavity with a source of metal melt; and at least one casting valve by which the metal melt is introduced into the cavity, wherein the supply channel forms an annular channel in which the metal melt is circulatable via a conveying apparatus.

2. The device according to claim 1, wherein the supply channel is integrated in a stationary part of the die casting mold.

3. The device according to claim 1, wherein the source of the metal melt comprises: a holding chamber; and a metal melt reservoir connected separably to the holding chamber.

4. The device according to claim 3, wherein the metal melt contained in the holding chamber is dischargable into the supply channel by a pressure generating device.

5. The device according to claim 3, wherein the supply channel leads into the holding chamber at at least two points.

6. The device according to claim 1, wherein the supply channel is formed, in at least one portion, from pipe pieces and connecting pieces that connect the pipe pieces.

7. The device according to claim 6, wherein the connecting pieces integrate channel portions having a curved profile.

8. The device according to claim 6, wherein the connecting pieces integrate the at least one casting valve.

9. The device according to claim 6, wherein the pipe pieces and the connecting pieces are formed from a same material.

10. The device according to claim 6, wherein the connecting pieces are heatable.

11. The device according to claim 1, wherein the conveying apparatus is configured to act electromagnetically.

12. The device according to claim 1, wherein: the casting valve has a valve body movable transversely with respect to a longitudinal axis of the supply channel, in a closed position of the valve body, the valve body closes an outlet opening connecting the supply channel to the cavity, and in an open position of the valve body, the valve body at least partially opens up the outlet opening.

13. The device according to claim 12, wherein the outlet opening is configured to widen in a direction of the supply channel, and a portion of the valve body is configured to taper in a direction of the cavity.

14. The device according to claim 12, wherein the casting valve integrates a squeezing plunger movable into a position projecting into the cavity.

15. The device according to claim 13, wherein the casting valve integrates a squeezing plunger movable into a position projecting into the cavity.

16. The device according to claim 11, further comprising a regulating device for the valve body, the regulating device being thermally insulated from the supply channel.

17. The device according to claim 14, further comprising a regulating device for the squeezing plunger, the regulating device being thermally insulated from the supply channel.

18. The device according to claim 16, wherein the regulating device is configured to act hydraulically.

19. The device according to claim 17, wherein the regulating device is configured to act hydraulically.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIG. 1 is schematic top view of an exemplary device according to the invention for die casting a metal component.

[0030] FIG. 2 shows part of the device according to FIG. 1 in a longitudinal section.

[0031] FIG. 3 shows a cross section through the illustration of FIG. 2 along the sectional plane

[0032] FIG. 4 shows part of the supply channel of the device according to FIG. 1 in a horizontal section.

[0033] FIGS. 5a to 5f show various positions of a casting valve of the device according to FIG. 1 within the context of die casting a metal component.

[0034] FIG. 6 shows a casting valve for a device according to FIG. 1 in a side view.

[0035] FIG. 7 shows a section through the casting valve according to FIG. 6 along the sectional plane VII-VII.

[0036] FIG. 8 shows the casting valve according to FIGS. 6 and 7 in a front view.

[0037] FIG. 9 shows a section through the casting valve according to FIG. 8 along the sectional plane IX-IX.

[0038] FIG. 10 shows a section through the casting valve according to FIG. 8 along the sectional plane X-X.

[0039] FIG. 11 shows a section through the casting valve according to FIG. 8 along the sectional plane XI-XI.

[0040] FIGS. 12a and 12b show a longitudinal section through an alternative embodiment of a casting valve for a device according to FIG. 1 in two switching positions.

[0041] FIGS. 13a and 13b show a longitudinal section through an alternative embodiment of a casting valve for a device according to FIG. 1 in two switching positions.

[0042] FIGS. 14a and 14b show a longitudinal section through an alternative embodiment of a casting valve for a device according to FIG. 1 in two switching positions.

[0043] FIG. 15 shows a front view of an alternative embodiment of a casting valve for a device according to FIG. 1.

[0044] FIG. 16 shows the casting valve according to FIG. 15 in a longitudinal section.

[0045] FIGS. 17a and 17b show a front view through an alternative embodiment of a casting valve for a device according to FIG. 1 in two switching positions.

[0046] FIGS. 18a and 18b show longitudinal sections through the casting valve according to FIGS. 17a and 17b in the two switching positions along the sectional plane XVIII-XVIII.

[0047] FIGS. 19a and 19b show a front view through an alternative embodiment of a casting valve for a device according to FIG. 1 in two switching positions.

[0048] FIGS. 20a and 20b show longitudinal sections through the casting valve according to FIGS. 17a and 17b in the two switching positions along the sectional plane XX-XX.

DETAILED DESCRIPTION OF THE DRAWINGS

[0049] FIG. 1 shows schematically a device for die casting a metal component. The device includes a die casting mold 1 which can be stored exchangeably in a press device 2. For the exchange, the die casting mold 1 can be moved out of or into the press device, for example along the double arrow 3. The die casting mold 1 has a lower part which is illustrated in FIG. 1 and is fixedly connectable to a stationary part (illustrated in FIG. 1) of the press device 2, and an upper part (not illustrated) which is fixedly connectable to a mobile part (not illustrated) of the press device 2. By movement of the mobile part of the press device 2 by way of hydraulic cylinders 4, the die casting mold can be closed, wherein the upper part of the die casting mold 1 then rests on the lower part of the die casting mold 1 in a sealing manner. A substantially closed cavity 5, which constitutes the negative mold of the component to be produced, is formed centrally here within the die casting mold 1. By moving the mobile part of the press device 2, the die casting mold 1 can be opened after the die casting and solidifying of the component, and the component can therefore be demolded.

[0050] A supply channel 6 for metal melt, from which the component is intended to be die cast, is integrated in the die casting mold 1, in a manner surrounding the cavity 5. The integration preferably takes place here in the stationary lower part of the die casting mold 1. The integration of the supply channel 6 in the die casting mold 1 can be provided in an exchangeable manner, for example by the corresponding elements (pipe pieces 7 and connecting pieces 8) of the supply channel 6 being arranged exchangeably in corresponding receiving openings or receiving depressions of a basic body of the die casting mold 1.

[0051] The supply channel 6 is composed of rectilinear pipe pieces 7 and connecting pieces 8. As can be seen from FIG. 4, the connection between the pipe pieces 7 and the connecting pieces 8 takes place by inserting an end of a pipe piece 7 adjacent to a connecting piece 8 into a corresponding receiving opening in the connecting piece 8. It can be provided here that the receiving openings have a defined excess size both in the radial and in the longitudinally axial direction of the pipe pieces 7 in order to compensate for a thermally induced elongation of said elements that occurs during operation. Sealing of the between the outer side of the inserted ends of the pipe pieces 7 and the inner walls of the corresponding receiving openings can take place by means of a separate sealing element 9, for example in the form of a metal O ring, in particular a Wills ring.

[0052] Channel portions 10 with a profile curved by 90 are integrated in the connecting pieces 8 arranged in the corners of the encircling supply channel 6. A respective casting valve 11 is integrated in the two centrally arranged connecting pieces 8. The casting valves 11 serve to introduce the metal melt contained in the supply channel 6 into the cavity 5 in a defined manner during the die casting of the component. If the cavity 5 is filled, the latter is separated from the supply channel 6 by closing of the casting valves 11. As a result, the metal melt contained in the cavity 5 can cure independently of the metal melt contained in the supply channel 6, and the component can be demolded after curing.

[0053] In order to avoid curing of the metal melt in the supply channel 6, the connecting pieces 8 are actively heated. For this purpose, the latter each include a heating device (not illustrated). The heating device can be operated in particular electrically. By contrast, no active heating is provided for the pipe pieces 7 (but is possible). The pipe pieces are therefore heated exclusively passively by transmission of heat from the metal melt, and are thereby brought to a temperature which approximately corresponds to that of the connecting pieces 8. In order to reduce a transmission of heat to the environment, the pipe pieces 7 in particular, but optionally also the connecting pieces 8, may be provided with thermal insulation on the outer side.

[0054] FIG. 4 also illustrates a connecting piece 8 which serves merely as a connecting socket 12 for two pipe pieces, and therefore neither integrates a curved channel portion 10 nor a casting valve 11. Such a connecting piece 8 can serve in particular to keep the length of the individual pipe pieces 7 connected thereto small.

[0055] It can preferably be provided to form the pipe pieces 7 and the connecting pieces 8 from the same material as far as possible. In particular, a ceramic material, such as, for example, aluminum titanate and/or silicon nitride, is suitable for this purpose. Such a ceramic material can be distinguished in particular by good high temperature stability and good chemical stability in relation to the metal melt (in particular in the case of an aluminum metal melt).

[0056] The device furthermore also includes a holding and supply part 13. A source for the metal melt is integrated therein. The source includes a holding chamber 14, which is temperature controlled by, in particular, an electric heating device, and a metal melt reservoir 15. The holding chamber 14 is connected to the metal melt reservoir 15 in a fluid conducting manner via an overflow line 16 (c.f. FIG. 3), wherein the fluid conducting connection is closable as required by means of an activatable melt valve 17, as a result of which a pressure proof separation can be achieved between the holding chamber 14 and the metal melt reservoir 15.

[0057] The holding chamber 14 is connected via two likewise temperature controlled connecting portions 18 (c.f. FIG. 2) of the supply channel 6 to that portion of the supply channel 6 which is formed in the die casting mold 1. A conveying apparatus 19 is integrated in each of the connecting portions 18. The conveying apparatuses are designed as electromagnetic circulating pumps. The connecting portions 18 are connected via preferably automatically releasable coupling devices 20 to that portion of the supply channel 6 which is integrated in the die casting mold 1.

[0058] In the present exemplary embodiment, the metal melt reservoir 15 is designed as a container which is open on its upper side and can be filled in a known manner via, for example, a metering ladle or a metering furnace. The overflow line 16 emerges from the bottom of metal melt reservoir 15 and leads to an overflow opening 21 which opens at a lowest point into the cylindrically designed holding chamber 14. The overflow opening 21 is closed or opened up by means of a casting plunger 22 depending on the switching position of the melt valve 17.

[0059] In a starting position of the device, in which the supply channel 6 is not yet filled with metal melt, the holding chamber 14 is first of all pre-filled. For this purpose, the melt valve 17 is opened, as a result of which the holding chamber 14 is filled by the hydrostatic pressure of the metal melt contained in the metal melt reservoir 15. For this purpose, in order to achieve as complete a filling of the holding chamber 14 as possible, the level in the metal melt reservoir 15 should always be at least as high as the highest point of the holding chamber 14. Venting of the holding chamber 14 during the pre-filling with metal melt can take place via the supply channel 6 and the open casting valves 11 (or one or more separate venting valves (not illustrated)). Furthermore, an operation of the conveying apparatuses 19, in which the two conveying apparatuses convey in the direction of the holding chamber 14 (i.e. in reverse), prevents metal melt that enters the holding chamber 14 from the metal melt reservoir 15 from overflowing via the connecting portions 18 into that portion of the supply channel 6 which is integrated in the die casting mold 1, and therefore a substantially complete pre-filling of the holding chamber 14 can be achieved.

[0060] Subsequently, the supply channel 6 can be filled with the metal melt. For this purpose, the melt valve 17 is reopened and at the same time the two conveying apparatuses 19 are switched in such a manner that they convey metal melt in the direction of the supply channel 6 (i.e. forward). In this case, the pre-filling of the holding chamber 14 ensures uninterrupted sucking up of metal melt from the metal melt reservoir 15. During the filling of the supply channel 6, the conveying apparatuses 19 can be driven at full power, which can lead to filling of the supply channel 6 with the metal melt under a pressure of, for example, at maximum 5 bar. As soon as the supply channel 6 is filled, one of the conveying apparatuses 19 continues to be operated forward at a reduced power of, for example, 20%, while the second conveying apparatus 19 continues to convey forward at an increased, for example full, power. This circuit of the conveying apparatuses 19 is referred to below as a circulation circuit. The circulation circuit of the conveying apparatuses 19 gives rise to a pressure difference between the two connecting portions 18 of the supply channel 6. The pressure difference ensures a constant circulation of the metal melt in the supply channel 6 forming an annular channel (together with the holding chamber 14).

[0061] For the die casting of a component, when the holding chamber 14 and supply channel 6 are filled, a casting plunger 22 is extended by way of an, in particular, hydraulic drive 23 in such a manner that the metal melt contained in the holding chamber 14 and the supply channel 6 is placed under pressure. The casting valves 11 are then opened and the quantity of metal melt required for the casting is pushed into the supply channel 6 via the casting plunger 22. After complete filling of the cavity 5 with the metal melt, the casting valves 11 close again. The circulation circuit of the conveying apparatuses 19 remains activated during the die casting.

[0062] The holding chamber 14 can subsequently be filled again in order to prepare the die casting of a further component. For this purpose, the melt valve 17 is opened and the casting plunger 22 moved back such that metal melt, assisted by the hydrostatic pressure, is sucked out of the metal melt reservoir 15 into the holding chamber 14. The holding chamber 14 is filled here with a quantity of metal melt which approximately corresponds to the quantity of the material required for the component. The volume and therefore the quantity of metal melt which can be introduced into the holding chamber 14 are adjustable via the position of the moved back casting plunger 22. If the holding chamber 14 is completely filled, the melt valve 17 is closed. During the refilling of the holding chamber 14, the circulation circuit of the conveying apparatuses 19 likewise remains activated. By means of the conveying of the two conveying apparatuses 19 in a forward direction, it can be avoided that the supply channel 6 is partially emptied during the refilling of the holding chamber 14, and the melt required for filling the holding chamber 14 is on the contrary sucked exclusively out of the metal melt reservoir 15.

[0063] Before a longer lasting interruption of the operation of the device, the supply channel 6, the holding chamber 14 and optionally also the metal melt reservoir 15 should be emptied. For this purpose, the two conveying apparatuses 19 are switched in reverse, and the melt valve 17 and, for ventilation purposes, the casting valves 11 (or the separate venting valves) are opened. The metal melt is then conveyed into the metal melt reservoir 15 by means of the conveying apparatuses 19. The metal melt reservoir 15 and also the holding chamber 14 can be completely emptied by opening an outlet valve 24 integrated in the overflow line 16. The emptied die casting mold 1 can be automatically decoupled and moved out of the press device 2.

[0064] The actuation of a casting valve 11 within the context of the die casting of a component is illustrated in FIGS. 5a to 5f in six steps or switching positions.

[0065] FIG. 5a shows the switching position of the casting valve 11, in which the latter is located while the cavity 5 of the die casting mold 1 is being prepared for the die casting. The cavity can be cleaned and sprayed with a releasing agent. A valve body 25 of the casting valve 11 is located here in a position closing an outlet opening 26 of the casting valve 11. Furthermore, a squeezing plunger 27 is positioned in a position extended in the direction of the cavity 5. The squeezing plunger 27 projects here beyond the valve body 25 into a sprue portion 28 of the cavity 5.

[0066] For the die casting, the squeezing plunger 27 is first of all moved into a drawn back position (cf. FIG. 5b) and subsequently the valve body 25 is also moved into an open position (cf. FIG. 5c).

[0067] After the complete filling of the cavity 5 with the metal melt, the valve body 25 is first of all closed (cf. FIG. 5d) and subsequently the squeezing plunger 27 is extended (cf. FIG. 5e). As a result, the metal melt is recompacted in the cavity 5, which is beneficial in a known manner for the quality of the die cast component.

[0068] The switching position according to FIG. 5e is maintained until the material solidifies in the cavity 5 and has cooled in a defined manner and can therefore be demolded. For the demolding, the squeezing plunger 27 is moved into the drawn back position (cf. FIG. 5f).

[0069] A possible configuration of the casting valve 11 is shown in various views and sectional illustrations in FIGS. 6 to 11.

[0070] The casting valve 11 includes a housing 29 which may be a housing of the corresponding connecting piece 8 of the supply channel 6 or which is integrated in an additional housing of such a connecting piece 8. The housing 29 has two housing parts 30, 31.

[0071] A first housing part 30 has, in integrated form, a first through opening, which forms a portion of the supply channel 6, and two receiving openings 32 which serve for receiving one end in each case of a pipe piece 7 of the supply channel 6 (cf. FIG. 4). Furthermore, a second through opening is integrated in the first housing part 30, the second through opening running perpendicularly to the first through opening and, in one portion, forming the outlet opening 26 of the casting valve 11 and, in another portion, serving for guiding the movable valve body 25. A portion of the outlet opening 26 that lies adjacent to the first through opening is designed so as to taper conically in the direction of the cavity 5. This portion of the outlet opening 26 serves as a valve seat for the valve body 25. The front end of the latter, which faces the outlet opening 26, is likewise designed so as to taper conically. It can be provided here that the angle which the conical lateral surface of the valve body 25 encloses with the longitudinal axis of the valve body 25 is smaller than the angle which the conical wall portion of the outlet opening 26 encloses with the longitudinal axis of the outlet opening. Furthermore, it can be provided that the conical portion of the lateral surface of the valve body 25 and/or the conical wall portion of the outlet opening 26 have/has a slightly curved profile, as a result of which a secure bearing of the valve body 25 over the complete circumference in the valve seat can be ensured.

[0072] A second housing part 31 includes two regulating devices in the form of coaxially oriented hydraulic cylinders. A first hydraulic cylinder situated closer to the first housing part serves for moving the valve body 25 while the squeezing plunger 27 is movable via the second hydraulic cylinder. For this purpose, that end of the squeezing plunger 27 which is spaced apart from the cavity 5 is connected directly to a plunger 33 which can be displaced within a cylinder tube 34 by the generation of a pressure difference on the two sides separate from the plunger 33. The first hydraulic cylinder likewise includes a plunger 35 which is displaceable by the generation of a pressure difference within a cylinder tube 41 of the first hydraulic cylinder. The plunger 35 which is in the shape of an annular disk is guided movably here on the squeezing plunger 27 which therefore extends through the first hydraulic cylinder, but without functionally influencing the latter. The plunger 35 of the first hydraulic cylinder is connected to the valve body 25 via three rods 36 positioned at a uniform pitch about the squeezing plunger 27.

[0073] Via an intermediate piece 37 which connects the two housing parts 30, 31 and is composed of a thermally comparatively readily insulating material, a transmission of heat from the metal melt guided in the first housing part 30 via the first housing part 30 to the second housing part 31 and the hydraulic cylinders integrated therein is kept small.

[0074] FIGS. 12 to 20 show different alternative embodiments for casting valves 11 which can be used in the device according to the invention according to FIG. 1.

[0075] FIGS. 12a and 12b show a casting valve 11 in which a cylindrical valve body 25 is mounted movably perpendicularly to the longitudinal axis of that portion of the supply channel 6 which is formed by a housing 29 of the casting valve 11. The outlet opening 26 of the casting valve 11 is formed cylindrically with an inside diameter approximately corresponding to the outside diameter of the valve body 25. In the closed position, the valve body 25 closes the outlet opening 26 by means of radial contact with the inner wall thereof (cf. FIG. 12a).

[0076] The casting valve 11 illustrated in FIGS. 13a and 13b differs from the casting valve 11 illustrated in FIGS. 12a and 12b in the configuration of the outlet opening 26 and of the valve seat formed by the latter. The outlet opening 26 is of stepped design and has a first portion adjacent to the cavity 5, in which the inside diameter is smaller than the outside diameter of the valve body 25. Located adjacent to the supply channel 6 is a second portion of the outlet opening 26, in which the inside diameter is slightly larger than the outside diameter of the valve body 25. In the closed position of the valve body 25, the latter therefore bears on the end side against the shoulder formed between the two portions of the outlet opening 26.

[0077] In the case of the valve illustrated in FIGS. 14a and 14b, the valve body 25 is arranged perpendicularly to the longitudinal axis of that portion of the supply channel 6 which is formed by the housing 29. The valve body 25 has a first through opening 38 extending in the direction of the longitudinal axis of the portion of the supply channel 6. From the first through opening 38, a second through opening 39 emerges in an eccentric arrangement with an orientation extending perpendicularly to the longitudinal axis of the first through opening 38. In the open rotational position of the valve body 25, the second through opening 39 merges into the outlet opening 26, as a result of which the supply channel 6 is connected in a fluid conducting manner to the outlet opening 26 via the two through openings 38, 39.

[0078] In the case of all of the casting valves 11 illustrated in FIGS. 5 to 14, the maximum outside diameter of the valve body 25 is smaller than the width or the diameter of that portion of the supply channel 6 which is formed by the casting valve 11. As a result, the metal melt can flow continuously around the valve body 11, and therefore a continuous circulation of the flow of the metal melt in the supply channel 6 forming an annular channel is made possible.

[0079] The casting valve 11 illustrated in FIGS. 15 and 16 includes a valve body 25 in the form of a displaceable valve plate arranged on the outer side of the housing 29 of the casting valve 11. For the casting valve 11, two (merely by way of example) outlet openings 26 are provided which are arranged offset in the direction of the longitudinal axis of that portion of the supply channel 6 which is formed by the casting valve 11, and which, in an open position of the valve plate, overlap with a respective through opening 40 in the valve plate. Displacement of the valve plate into a closed position leads to a covering of the outlet openings 26 by the valve plate.

[0080] In the case of the casting valve 11 illustrated in FIGS. 17 and 18, use is made of a bushing shaped valve body 25 which bears against the wall of that portion of the supply channel 6 which is formed by the casting valve 11. The bushing-shaped valve body 25 has a radially running through opening 40 which overlaps with the outlet opening 26 in an (opening) rotational position. By rotation of the bushing shaped valve body 25 about the longitudinal axis of the portion of the supply channel 6 by, for example, approx. 30, the through opening 40 is brought out of overlapping with the outlet opening 26 and the casting valve is therefore closed.

[0081] The casting valve 11 illustrated in FIGS. 19 and 20 likewise includes a bushing shaped valve body 25 with a through opening 40 which can be brought into overlap with the outlet opening 26, wherein, in this case, the opening or closing of the casting valve 11 is brought about by displacement of the bushing shaped valve body 25 in the direction of the longitudinal axis of that portion of the supply channel 6 which is formed by the casting valve 11.

LIST OF REFERENCE NUMBERS

[0082] 1 Die casting mold [0083] 2 Press device [0084] 3 Movement directions during the exchanging of the die casting mold [0085] 4 Hydraulic cylinder [0086] 5 Cavity [0087] 6 Supply channel [0088] 7 Pipe piece [0089] 8 Connecting piece [0090] 9 Sealing element [0091] 10 Curved channel portion [0092] 11 Casting valve [0093] 12 Connecting socket [0094] 13 Holding and supply part [0095] 14 Holding chamber [0096] 15 Metal melt reservoir [0097] 16 Overflow line [0098] 17 Melt valve [0099] 18 Connecting portion [0100] 19 Conveying apparatus [0101] 20 Coupling device [0102] 21 Overflow opening [0103] 22 Casting plunger [0104] 23 Drive of the casting plunger [0105] 24 Outlet valve [0106] 25 Valve body of the casting valve [0107] 26 Outlet opening [0108] 27 Squeezing plunger [0109] 28 Sprue portion [0110] 29 Housing of the casting valve [0111] 30 First housing part [0112] 31 Second housing part [0113] 32 Receiving openings [0114] 33 Plunger of the second hydraulic cylinder [0115] 34 Cylinder tube of the second hydraulic cylinder [0116] 35 Plunger of the first hydraulic cylinder [0117] 36 Rod [0118] 37 Intermediate piece [0119] 38 First through opening [0120] 39 Second through opening [0121] 40 Through opening [0122] 41 Cylinder tube of the first hydraulic cylinder

[0123] The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.