CN100513011C - Die casting mold and improved vent structure used therein - Google Patents

Abstract

The invention discloses a die-casting mold, which comprises a blocking member (17) arranged in a discharge channel (16) to reduce the flow velocity of the molten metal when the molten metal moves forward along the discharge channel. The blocking member comprises a plurality of discrete protrusions (24) arranged staggered longitudinally and transversely of the discharge channel so as to define therebetween a meander (34) extending between the inlet side and the outlet side of the discharge channel.

Description

Die casting mold and improved discharge structure used therein

technical field

The present invention relates to an improvement to a die casting mold having a chill vent structure which allows air and/or gas to escape from the cavity while preventing The molten metal splashes to the outside of the die-casting mold while inside the cavity.

Background of the invention

A die-casting mold having a cooling discharge structure has been disclosed, for example, in Japanese Patent Laid-Open (JP-A) No. 11-151564, wherein the cooling discharge structure allows the remaining Metal is hydraulically injected into the cavity under pressure without splashing unsolidified molten metal. The cooling discharge structure of the disclosed die casting mold will be described below with reference to FIG. 7 .

As shown in FIG. 7, the cooling drain structure includes a cooling drain block 100 consisting of a pair of drain halves or members 102 and 104 secured to a mating pair of die-cast molds 101 and 103, respectively. The vents 102, 104 have corrugated opposing surfaces so as to define a zigzag vent passage 105 between the vents when the modules 101, 103 are brought together to close the die casting mould. The zigzag discharge channel 105 communicates with a cavity 106 formed between the die pieces 101 , 103 . Due to this arrangement, when metal is hydraulically injected into the cavity 106 under pressure, residual air and/or gas in the cavity 106 can escape from the discharge channel 105, resulting in splashing of unsolidified molten metal from the cavity 106. Exhaust channel 105 . In this example, due to the relatively long flow path provided by the serrated discharge channel 105 , splashed unfreezed molten metal is cooled by the discharge members 102 , 104 and solidifies within the discharge channel 105 . In this way, unsolidified molten metal can be prevented from splashing or ejecting from the die-casting mold.

However, since the cooling discharge block 100 is formed by a pair of half-discharge bodies or pieces 102, 104, which are fixed respectively on a pair of cooperating mold parts 101, 103 of the die-casting mold, the overall size of the die-casting mold is relatively large. Furthermore, manufacturing the discharge members 101 , 103 with corrugated surfaces requires high-precision machining, which increases the production cost of the cooling discharge block 100 . Furthermore, the corrugated ejector surface tends to prevent the die casting or casting from the die casting 101 , 103 from being smoothly separated when the casting is removed from the die casting mold. Moreover, when changing the depth t ( FIG. 7 ) of the discharge channel 105 or the apex angle θ ( FIG. 7 ) of the triangular ridge on the surface of the corrugated discharge member to adjust the flow rate of the molten metal when the molten metal moves forward along the discharge channel 105 , the discharges 102, 104 as a single cooling block should be replaced with another pair of discharges of the desired configuration. Such a replacement of a pair of outlets entails high additional costs.

In view of the above-mentioned difficulties of conventional devices, it is desirable to provide a die-casting mold with a cooling discharge structure that is relatively small in size, simple in structure and low in manufacturing cost, and capable of Assembled with die casting mold.

Contents of the invention

According to one aspect of the present invention, there is provided a die-casting mold, comprising: a fixed mold member; a movable mold member movable toward and away from the fixed mold member to define a cavity therebetween when the die-casting mold is closed; a discharge channel formed at In the mating surface of one of the fixed mold and the movable mold and extending to communicate with the cavity, so that the remaining gas escapes from the cavity when the molten metal is injected into the cavity; In the passage, to reduce the flow velocity of the molten metal when the molten metal advances along the discharge passage, wherein the barrier includes a plurality of discontinuous protrusions arranged in a longitudinal direction and a transverse direction of the discharge passage alternately, so that between the protrusions The gap defines a labyrinthine part extending between the inlet side and the outlet side of the discharge channel.

Due to this arrangement, the blocking member is disposed in the discharge passage formed in the mating surface of the fixed mold part or the movable mold part. This means that the stopper is arranged inside the die-casting mold and does not increase the overall size of the die-casting mold. Also, since the stopper can be formed by processing only one mold, compared with a conventional die-casting mold having a cooling discharge block formed by a pair of discharges of a pair of molds respectively fixed to the die-casting mold, the Production costs are relatively low.

Preferably, the mating surface of the other of the fixed and movable mold parts has a flat portion adapted to abut the top surface of the protrusion. The casting can be easily removed from the die casting mold due to the fact that the flat mating surface portion is unlikely to stick to the die casting or the material of the casting.

Preferably, the top surface of the protrusion is flat and engages in flatways with a flat mating surface portion of the other module. Due to this arrangement, when the mold is held in a closed state under a predetermined clamping force, the stopper is stably held without causing deformation of the protrusion. In this way, the cross-sectional area of the meandering discharge channel part remains substantially constant during the die-casting process and does not adversely affect the die-cast part or the quality of the cast part.

The meander part of the discharge channel comprises a plurality of parallel spaced first grooves extending longitudinally of the discharge channel and a plurality of parallel spaced second grooves extending transversely of the discharge channel. The second groove may be deeper than the first groove so as to be able to obtain a desired barrier when the molten metal advances along the tortuous discharge channel part.

In a preferred form of the invention, the barrier is formed by a partition structurally independent of and removably mounted to one of the modules. The blocking member includes a flat plate-like bottom detachably mounted to one module and a protrusion formed on one surface of the flat plate-like bottom.

In this way, by preparing two or more stoppers different in the number and size of the protrusions, the stoppers can be appropriately changed according to the desired quality of the produced die-cast or casting. More specifically, since the flow rate of molten metal varies with the cross-sectional area of the discharge channel as the molten metal advances along the discharge channel by changing the barrier in an appropriate manner, the flow rate of molten metal at the barrier can be easily adjusted To the extent that residual air and/or gas in the cavity is completely evacuated and does not enter the molten metal which would otherwise cause porosity in the die casting or casting etc., thereby reducing the product quality of castings. In this way it is possible to obtain castings of the desired quality without having to adjust and prepare die casting molds for a long period of time.

Also, by standardizing the size and shape of the bottom of each stopper and the size and shape of the fixing grooves in which the seats in which the stoppers are fixed, one stopper can be used in combination with a plurality of different molds, or alternatively it is possible to use Several different barriers are used in combination with one mould. Due to this arrangement, the maintenance cost of the die-casting mold can be reduced.

According to another aspect of the present invention, there is provided a cooling discharge structure for a die-casting mold, comprising a flat plate-like bottom; and a plurality of discontinuous protrusions formed on one surface of the flat plate-like bottom and arranged alternately with each other, In order to define a meandering discharge channel therebetween.

Due to the tortuous configuration, the discharge channel is able to provide a relatively long flow path and a relatively large resistance to the movement of the molten metal as it progresses along the discharge channel. In this way, the molten metal cools and solidifies as it progresses along the tortuous discharge channel. Undesired splashing or ejection of unsolidified molten metal from the die-casting mold can thus be avoided.

Description of drawings

Preferred embodiments of the present invention will be described in detail below, by way of example only, with reference to the accompanying drawings, in which:

1 is a vertical cross-sectional view showing a die-casting mold according to an embodiment of the present invention;

Figure 2 is an enlarged view of a portion of Figure 1, represented by the circle 2 shown in Figure 1;

Fig. 3 is a schematic diagram in the direction of arrow 3 shown in Fig. 2;

Figure 4 is a perspective view of the barrier shown in Figure 3;

Figure 5 is a view similar to Figure 3, but showing the manner in which residual air and/or gas in the cavity is partially exhausted through the tortuous exhaust channel formed in the barrier;

6A, 6B, 6C and 6D are diagrams showing the sequence of operations of the die casting process performed on the die casting mold; and

Fig. 7 is a cross-sectional view showing a cooling discharge structure incorporated in a conventional die-casting mold.

Detailed ways

Reference is first made to FIG. 1 which shows a cross-section of a die casting die 10 embodying the invention. The die-casting mold 10 includes a fixed mold part 11 and a movable mold part 12 movable toward and away from the fixed mold part 11 , and a cavity 13 is defined between the fixed mold part and the movable mold part when the die-casting mold 10 is closed. The movable mold part 12 is installed on the mold base 20 of the die-casting machine. While the die-casting mold 10 is held closed, a die-casting part or casting 39 is formed by driving a die punch 14 that reciprocates within a shot cylinder 15 to hydraulically force metal under pressure into the cavity 13 .

The stationary part 11 has a discharge channel 16 formed in its mating face 26 (FIG. 2). When the mold 10 is closed, the discharge channel 16 extends to communicate with the cavity 13 . In this way, when molten metal is injected into the cavity 13 , the remaining air and/or gas in the cavity 13 can escape through the discharge channel 16 . A cooling discharge block (blocker) 17 is provided in the discharge channel 16 to reduce the flow velocity of the molten metal as it proceeds along the discharge channel 16 .

The exhaust valve 18 comprises a poppet incorporated in the fixed mold 11 for opening and closing the outlet end of the discharge passage 16 . The poppet valve 18 has a stem 19 received in a valve hole 21 formed in the fixed mold member 11 . The valve hole 21 has one end connected to the outlet end of the exhaust passage 16 and the opposite end closed by a driver (not shown) of the exhaust valve 18 . The valve hole 21 is connected to an inlet port of an exhaust passage 22 formed in the fixed mold part 11 , and an outlet end of the exhaust passage 22 is connected to an exhaust ventilation device (not shown) provided outside the die-casting mold 10 .

Due to this arrangement, when the metal is hydraulically injected into the cavity 13 under pressure and the mold 10 is in the closed state, the remaining air and/or gas in the cavity 13 is successively discharged to the outside of the mold 10 through the discharge channel 16, which It includes a cooling discharge block 17 , a valve hole 21 and an exhaust passage 22 . In this example, the external exhaust ventilation device (not shown) is continuously driven, and the opening and closing operation of the exhaust valve (poppet valve) 18 is adjustedly controlled, so that the exhaust valve 18 first opens the discharge passage 16 so that the type The remaining air and/or gas in the cavity 13 can escape and then close the outlet channel 16 until the die casting mold 10 is filled with the molten metal.

FIG. 2 shows a cross-section of the barrier 17 arranged in the discharge channel 16 and extending between the cavity 13 and the valve opening 21 . The blocking member 17 is detachably connected to a seat 27 fixedly installed in the fixed mold part 11 by a bolt 28 . In this way, the blocking member 17 is removably mounted on the fixing member 11 .

The blocking member 17 includes a flat plate-like bottom 23 (see FIG. 4 ) and a plurality of discrete protrusions 24 integrally formed with the bottom 23 and protruding from one surface thereof. The base 23 fits in a fixing groove 35 formed in the seat 27 . Protrusions 24 each have a flat top surface 25 that comes into face-to-face contact with a flat mating surface 26 of movable mold member 12 when mold 10 (FIG. 1) is closed. The protrusions 24 are positioned within the discharge channel 16 so that as the molten metal advances along the discharge channel 16, the molten metal hits the protrusions 24 and its forward motion is slowed down. In this way, the protrusion 24 acts to hinder the smooth forward movement of the molten metal, and thus reduces the flow rate of the molten metal as it advances along the discharge channel 16 .

Since a portion of the mating surface 26 of the movable mold part 12 is flat and this part contacts the top surface 25 of the protrusion 24, when the die casting 39 (FIG. 1) is removed from the mold 10, the solidified metal in the discharge channel 16 The splashed part of the liquid is unlikely to collide with the mating surface part of the movable module 12 . The die-cast part 39 can thus be removed from the mold 10 smoothly.

In the illustrated embodiment, the blocking member 17 is mounted in the stationary mold part 11 having a protrusion 24 arranged in the discharge channel 16 with its top surface 25 facing the movable mold part 12 . Alternatively, the blocking member 17 may be installed in the movable module 12 . In the latter case, the movable module 12 has a discharge channel formed in a mating surface 26 for receiving therein the protrusion 24 of the barrier 14 , the protrusion having a top surface 25 facing the fixed module 11 .

Figure 3 shows the blocking member 17, mounted on the seat 27, with the exhaust valve (poppet valve) 18 and valve stem 19 omitted for clarity. The seat 27 is fixedly integrated in the fixed mold part 11, so that the front surface of the seat 27 forms a part of the mating surface 26 of the fixed mold part 11, in which part the discharge channel 16 is formed. The discharge passage 16 includes an inlet side portion 31 , outlet side portions 32L, 32R, 33L, 33R, and a central portion 34 disposed between the inlet side portion 31 and the outlet side portions 32L, 32R, 33L, 33R. The inlet-side portion 31 of the discharge passage 16 is connected to the cavity 12 ( FIG. 2 ) at one end (upstream end) and to the center portion 34 at the other end (downstream end). The outlet side portions 32L, 32R, 33L, 33R of the discharge passage 16 include a plurality (four in the illustrated embodiment) of longitudinal passages 32L, 32R connected to the central portion 34 at upstream ends, and two longitudinal passages 32L The downstream ends of , 32R are connected to the valve hole 21 through transverse passages 33L, 33R. The central portion 34 of the discharge passage 16 has a zigzag structure formed between the plurality of protrusions 24 and arranged alternately in the longitudinal and transverse directions of the discharge passage 16 . The stopper 17 forming the central portion 34 of the discharge passage 16 has a two-piece structure including a left stopper portion 17L and a right stopper portion 17R of the same structure arranged side by side. Obviously, the barrier 17 may have a one-piece structure formed from a single piece of metal block.

As shown in FIG. 4 , the protrusions 24 formed on the front surface of the flat-like bottom 23 are separated by a plurality of parallel spaced longitudinal grooves 34 a and a plurality of parallel spaced transverse grooves 34 b, which form the discharge channel 16 The meandering center piece or portion 34 . Longitudinal grooves 34 a are defined between the protrusions 24 and transverse grooves 34 b are formed in the front surface of the bottom 23 . In this way, the transverse grooves 34 b are made deeper than the longitudinal grooves 34 a in order to be able to create the desired barrier when the molten metal advances along the central portion 34 of the discharge channel 16 . The transverse groove 34b may suitably have the same depth as the transverse groove 34b.

As mentioned above, the blocking member 17 is removably mounted on the fixed mold member 11 . Therefore, by arranging two or more stoppers whose protrusions are different in number and size, the stopper 17 can be appropriately changed according to the desired quality of the produced die-casting or casting. More specifically, since the flow rate of the molten metal varies with the cross-sectional area of the discharge passage 16 as the molten metal proceeds along the discharge passage 16, by changing the barrier in an appropriate manner, the central portion 34 of the discharge passage 16 can be The flow rate of the molten metal is adjusted to the extent that the remaining air and/or gas in the cavity is completely discharged and does not enter the molten metal, and the remaining air and/or gas entering the molten metal will cause pores in the die casting or casting, etc. . In this way it is possible to obtain castings of the desired quality without having to adjust and prepare die casting molds for a long period of time.

Also, by standardizing the size and shape of the bottom 23 of each stopper 17 and the size and shape of the fixing groove 35 (FIG. 2) of each seat 27, one stopper 17 can be used in conjunction with a plurality of different molds, or, Ability to use several different barriers with one mould. Due to this arrangement, an increase in the size of the die-casting mold can be avoided, and the maintenance cost of the die-casting mold can be reduced.

As previously mentioned, the protrusions 24 of the blocking member 17 are arranged alternately in the longitudinal and transverse directions of the discharge channel 16 , thereby defining a meandering discharge channel part 34 extending between the inlet side and the outlet side of the discharge channel 16 . As a result, unsolidified molten metal that may splash out of the cavity 13 (FIG. 2) while evacuating the remaining air and/or gas within the cavity 13 will proceed in a zigzag or zigzag fashion along the tortuous discharge channel member 34. , as indicated by the arrow X shown in Figure 5. During this period, as the molten metal hits the protrusion and enters the transverse groove 34b, the flow rate of the molten metal is effectively reduced to such an extent that the molten metal is cooled by the mating surface 26 of the barrier member 17 and the movable mold member 12 and in its It solidifies before reaching the downstream end of the discharge passage where the discharge valve (poppet valve) 18 is provided.

The die-casting process performed by the die-casting machine in which the die-casting mold 10 of the foregoing structure is incorporated will be described below with reference to FIGS. 6A to 6D.

As shown in FIG. 6A, the die casting machine is operated to move the movable mold part 12 toward the fixed mold part 11, thereby closing the mold 10 and forming a cavity 13 therein. The mold 10 is held in this closed state with a predetermined pressing force. In this example, cylinder 15 is filled with molten metal 39 . The exhaust passage 22 is connected to an exhaust ventilation device (not shown) provided outside the mold 10 . The exhaust ventilation is normally driven for continuous exhaust while running the die casting machine.

Then, the die punch 14 is driven to press or inject molten metal 39 into the cavity 13 at a low speed, as shown in FIG. 6B . In this example, the exhaust valve 18 ( FIG. 1 ) provided at the downstream end of the exhaust passage 16 is opened, so that the remaining air and/or gas in the cavity passes through the exhaust valve including the stopper 17 , the valve hole 21 and the exhaust passage 22 successively. The channel 16 is exhausted to the outside of the mold 10, as indicated by arrow "a" as shown in FIG. 6B.

It may occur that molten metal 39 splashes from cavity 13 into outlet channel 16 . However, due to the meandering discharge channel part 34 ( FIG. 5 ) formed between the protrusions 24 of the stopper 17 , it takes a relatively long time to fill the discharge channel part 34 with the molten metal 39 . This ensures that the remaining air and/or gas within the cavity 13 , including the air and gas inside the molten metal 39 , is completely vented to the outside of the mold 10 . Like this, while injecting molten metal 39 into cavity 13 at low speed, open exhaust valve 18 (Fig. Air and/or gas escape. The opening time of the exhaust valve 18 is determined based on information obtained through trials, accumulated data, experiments, cycles and mold quality.

Subsequently, the advancing speed of the die punch 14 changes from a low speed to a high speed, so that the molten metal 39 held inside the cylinder 15 is injected into the cavity 13 at a high speed, so that the cavity 13 is filled with the molten metal 39, as shown in FIG. 6C . The punching speed is determined experimentally. While the punch speed is increasing, the vent valve 18 ( FIG. 1 ) is closed, thereby blocking the communication between the vent passage 16 and the vent passage 22 .

Then, the movable mold part 12 is moved backward away from the fixed mold part 11, and the die casting or casting 41 is removed from the mold 10, as shown in FIG. 6D. The single cycle operation of the die casting process is thus completed.

As explained, the blocking member 17 comprising a plurality of discontinuous protrusions 24 (FIG. 2) is arranged in the discharge channel 16 formed in the mating surface 26 of the fixed mold part 11, so as to block or hinder the smooth movement of the molten metal, thereby The flow rate of the molten metal is reduced as the molten metal advances along the discharge channel 16 . The stopper 17 is provided within the die-casting mold 10 and thus does not increase the overall size of the mold 10 . Furthermore, since the meandering discharge channel part 34 ( FIG. 4 ) is formed between the protrusions 24 of the barrier 17 , the velocity of the molten metal forward along the meandering discharge channel 34 is greatly reduced. This means that it takes a relatively long time to fill such a discharge channel part 34 with molten metal, with the result that the remaining air and/or gas (including the air and/or gas in the molten metal) in the cavity 13 can be completely discharged. Discharged to the outside of the mold 10. In addition, the molten metal is effectively cooled by the mating surface 26 ( FIG. 2 ) of the barrier member 17 and the movable module 12 when moving forward along the tortuous discharge channel part 34 , and when the molten metal reaches the discharge channel 16 and the valve hole 21 (Fig. 2) before the joints solidify.

In the illustrated embodiment, the blocking member 17 having a plurality of discrete protrusions 24 interleaved with each other is integrated within the stationary mold member 11 as a single component that is structurally independent of the stationary mold member 11 . The invention is in no way limited to the illustrated arrangement, but may include variations in which the discrete protrusions 24 are integrally formed with the fixed mold part 11 . In the latter case, since the stopper 17 can be formed only by machining the mating surface 26 of the fixed mold part 11, the stopper 17 can be produced at reduced cost. The blocking member 17 may be integrated in the movable module 12 , in this example the discharge channel 16 is formed in a mating face 26 of the movable module 12 .

When the die-casting mold 10 is closed, the top surface 25 of the protrusion 24 of the stopper 17 and the mating surface of the movable mold part are in contact with each other. In this example, since the top surface 25 of the protrusion 24 is flat, a relatively large contact area with respect to the flat mating surface 26 of the movable module 12 can be provided, and the stopper 17 can be stably held without causing the protrusion 24 The deformation of the protrusions is caused by the different clamping forces applied to the fixed mold part 11 and the movable mold part 12. In this way, the cross-sectional area of the discharge channel part 34 of the barrier 17 remains substantially constant during the die casting process and does not adversely affect the die casting or the quality of the casting.

Industrial Applicability

Due to the arrangement described so far, the present invention can be advantageously used as a mold for synthetic resin molding processing.

Claims (8)

1. A die-casting mold, comprising: Fixed module; a movable mold member movable toward and away from the stationary mold member to define a cavity therebetween when the die-casting mold is closed; a discharge passage formed in the mating surface of one of the fixed mold part and the movable mold part and extending to communicate with the cavity to allow residual gas to escape from the cavity when molten metal is injected into the cavity; and a barrier, arranged in the discharge channel to reduce the flow rate of the molten metal when the molten metal advances along the discharge channel, wherein the barrier comprises a plurality of discontinuous protrusions arranged in a longitudinal direction and a transverse direction of the discharge channel alternately, A meander extending between the inlet side and the outlet side of the discharge channel is thus defined between the protrusions. 2. The die casting mold of claim 1, wherein the other of the stationary and movable mold parts has a mating surface including a flat portion adapted to abut the top surface of the protrusion. 3. The die casting mold of claim 2, wherein the top surface of the protrusion is flat and partially engages a flat mating surface of another mold in planar contact. 4. The die-casting mold as claimed in claim 1, wherein the meandering part of the discharge channel comprises a plurality of parallel spaced first grooves extending in the longitudinal direction of the discharge channel and a plurality of parallel spaced first grooves extending in the transverse direction of the discharge channel. a second groove, the second groove is deeper than the first groove. 5. The die casting mold of claim 1, wherein said barrier is formed by a partition that is structurally independent from and removably mounted to one of the modules, the barrier including a A module's flat-like bottom and protrusions formed on a surface of the flat-like bottom. 6. A cooling discharge structure for a die-casting mold, comprising: a slab-like bottom; and A plurality of discontinuous protrusions are formed on one surface of the flat plate-like bottom and are arranged alternately to define a meandering discharge channel therebetween. 7. The cooling drain structure of claim 6, wherein the protrusion has a flat top surface. 8. The cooling discharge structure as claimed in claim 6, wherein said discharge passage comprises a plurality of parallel spaced first grooves extending longitudinally of the discharge passage and a plurality of parallel spaced second grooves extending transversely of the discharge passage. groove, the second groove is deeper than the first groove.

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