JP4818733B2 - Die casting plunger - Google Patents

Description

  The present invention relates to a die casting plunger for pressing a molten metal during die casting.

  Conventionally, in die casting, after supplying a predetermined molten metal into a plunger sleeve communicating with a cavity of a molding die, the molten metal in the sleeve is pressed by the plunger and injected into the cavity, and the cavity is filled. After the molten metal was cooled and solidified, a molded product was obtained from the molding die. In this die casting, in order to prevent casting defects such as sinkholes from occurring when the molten metal filled in the cavity is solidified, a plunger (biscuit) on the plunger tip side in the sleeve is Further pressing is performed to increase the pressure of the molten metal filled in the cavity.

  By the way, the biscuit portion described above needs a certain volume to prevent casting defects. Therefore, even if the melt of the product portion filled in the cavity is solidified, the melt of the biscuit portion cannot be completely solidified. The molded product could not be removed from the mold until the molten metal in the part solidified. Therefore, in order to shorten the solidification time of the biscuits, there is known a structure in which a circulation space through which cooling water can flow is formed inside the plunger and the biscuits are cooled via the plunger.

JP 2001-150116 A

  However, conventional plungers use carbon steel, tool steel, etc., which have a relatively low thermal conductivity, in order to increase wear resistance due to sliding in the sleeve, and it takes time to cool the biscuits and die casting. It has been difficult to further reduce the cycle time in casting.

  Therefore, it is conceivable to reduce the thickness of the plunger tip to increase the thermal conductivity. However, in this case, since the rigidity of the plunger tip decreases as the wall thickness decreases, the plunger tip may crack due to the reaction force applied when the molten metal is pressed, causing water leakage. The thickness of the tip could not be made suitable for the cooling efficiency, and the cooling efficiency of the biscuits could not be dramatically increased.

  Further, it is conceivable to use a metal material having a high thermal conductivity such as a beryllium copper alloy as a material used for the plunger. However, in this case, since the wear resistance is low compared to carbon steel or the like, the plunger must be worn out and replaced at an early stage. There is an increasing problem.

  Therefore, the present invention has been made in view of the above-mentioned actual situation, and an object thereof is to provide a die casting plunger that improves the cooling efficiency of the biscuit portion in die casting and shortens the cycle time and has excellent wear resistance. Is.

In order to solve the above problem, a plunger for die casting according to the present invention is:
“A plunger for die casting that is inserted into a sleeve to which molten metal is supplied and is capable of pressing the supplied molten metal and is supplied with cooling water,
A cylindrical sliding surface that is in sliding contact with the inner surface of the sleeve, a connection hole that is smaller in diameter than the sliding surface, opens at the proximal end, is drilled toward the distal end, and the distal end of the plunger rod is connected and fixed; large diameter portion and a small diameter portion and the Bei Barcelo plunger body mounting hole that is a stepped hole by penetrating from the base end side of the large diameter portion to more the connection holes than the diameter of the sliding surface open to the tip diameter When,
A columnar exposed portion that closes the distal end opening of the mounting hole of the plunger body and is exposed to the outside and inserted into the large diameter portion, and a protrusion that protrudes from the proximal end side of the exposed portion and is inserted into the small diameter portion A distal end member made of a metal material that is fixed to the plunger main body and has a higher thermal conductivity than the plunger main body.
A seal member for watertightly sealing between the plunger main body and the tip member at the position of the protruding portion of the tip member ;
The distal end member is attached to the mounting hole of the plunger main body, and in the state where the plunger rod is connected to the connection hole, there is a flow space in which cooling water supplied from the plunger rod can flow. . "

  Here, examples of the “metal material having high thermal conductivity” include “copper alloys such as beryllium copper”, and it is desirable to use a metal material having higher thermal conductivity than the material used for the plunger body.

  According to the present invention, the tip member made of a metal material having high thermal conductivity is fixed to the tip of the plunger body so as to be exposed to the tip of the plunger body and the flow space in the plunger body. That is, the tip of the tip member having high thermal conductivity is in direct contact with the molten metal, and the base end is in direct contact with the cooling water. As a result, the thermal conductivity at the tip of the plunger is increased and the cooling efficiency of the biscuit portion can be increased, so that the solidification time of the biscuit portion can be shortened. That is, the cycle time in die casting can be shortened and productivity can be improved.

  In addition, the tip member is made of a metal material with high thermal conductivity, and it becomes possible to increase the cooling efficiency without increasing the heat transfer amount by reducing the tip thickness like conventional plungers. Therefore, it is possible to increase the cooling efficiency of the biscuit portion while maintaining the rigidity of the plunger, and it can also be used for die casting with a high pressing force against the molten metal.

  By the way, the plunger body is made of a metal material having high thermal conductivity such as beryllium copper alloy, and the sleeve made of a metal material having excellent wear resistance is fitted on the outer periphery of the plunger body, thereby being resistant to the plunger. However, in this case, since the plunger main body that occupies most of the plunger is an expensive metal material, there is a problem that the cost of the plunger is greatly increased.

  However, according to the present invention, since a relatively expensive metal material with high thermal conductivity is used only for the tip member fixed to the tip of the plunger, it is possible to suppress an increase in the cost of the plunger, By using an inexpensive material with excellent wear resistance for the plunger main body, a plunger with high cooling efficiency and excellent wear resistance can be realized.

  The plunger main body and the tip member may be fixed so as to be detachable from each other. For example, when the plunger is discarded, the plunger main body and the tip member made of different materials can be easily disassembled. This can reduce the cost for disposal. In addition, when either the plunger body or the tip member is consumed, the plunger body and the tip member are disassembled, the worn one is replaced, and the usable one is reused to reduce the cost of the plunger. Can do.

  In addition, a predetermined hole such as a blind hole may be formed in the tip member so that the cooling water supplied to the circulation space of the plunger main body may be supplied to the inside of the tip member. The cooling efficiency can be further increased.

Here, the "watertight" is "what a watertight by interposing the seal member such as an O-ring or gasket between the plunger body and the tip member", and the like. As a result, the sealing member is disposed at a position where it is easily cooled by the cooling water supplied into the plunger main body, so that the sealing member is prevented from being deteriorated or burned out by the heat of the molten metal, and the sealing effect is good. Can be maintained.

  According to the present invention, the tip member is fixed to the plunger main body in a watertight manner. Thereby, it can prevent that a cooling water leaks from between a plunger main body and a front-end | tip member, and can prevent that a malfunction generate | occur | produces by a water leak.

  As described above, according to the present invention, it is possible to provide a die casting plunger that improves the cooling efficiency of the biscuit portion in die casting and shortens the cycle time and is excellent in wear resistance.

  Next, an embodiment of a plunger for die casting according to the present invention will be described in detail with reference to FIGS. FIG. 1 is a sectional view showing a schematic configuration of a die casting machine using the die casting plunger of the present invention. 2A is a cross-sectional view of a die casting plunger according to an embodiment of the present invention, and FIG. 2B is a perspective view of the die casting plunger shown in FIG. 3A is an exploded sectional view of the plunger for die casting shown in FIG. 2, and FIG. 3B is an exploded perspective view of the plunger for die casting shown in FIG.

  As shown in FIG. 1, a die casting machine 1 includes a stationary platen 3 to which a fixed die 2 is attached, a movable platen 5 to which a movable die 4 is attached, and a movable platen 5 that supports the fixed platen 3 although not shown. And a movable platen drive device for moving the movable platen 5 although not shown. Molding that is die-cast between the fixed mold 2 and the movable mold 4 by moving the movable disk 5 in the direction of the fixed disk 3 by the movable disk drive device and matching the fixed mold 2 and the movable mold 4 with each other. A cavity 6 composed of a space corresponding to the product is formed.

  Further, the die casting machine 1 includes a plunger sleeve 8 having a cylindrical inner surface which is attached to the fixed platen 3 through a cavity 6 and a runner 7 formed by a fixed mold 2 and a movable mold 4, and a plunger sleeve. A plunger 10 that slides inside 8 and is fixed to the tip of the plunger rod 9 and a plunger drive device that drives the plunger 10 forward and backward through the plunger rod 9 although not shown. As shown in the figure, a biscuit portion 7a serving as a hot water reservoir having a predetermined volume is formed between the plunger sleeve 8 communicating with the runner 7 on the distal end side of the plunger 10 moved to the forward movement position by the plunger driving device. When the molten metal filled in the cavity 6 is cooled and solidified, the plunger 10 is pressurized by the plunger driving device, and the molten metal of the biscuit portion 7a is supplied to the cavity, thereby causing a casting defect. It is designed to prevent this.

  Note that a spout 11 for supplying molten metal made of molten metal into the plunger sleeve 8 is provided between a forward position and a backward position (position indicated by a two-dot chain line in the figure) of the plunger 10 that is advanced and retracted by the plunger driving device. Is provided. Although not shown, a circulation channel for circulating the coolant supplied to the plunger 10 is formed inside the plunger rod 9.

  Next, the plunger 10 of this embodiment will be described in detail. As shown in FIGS. 2 and 3, the plunger 10 includes a plunger main body 13 having a flow space 12 in which the cooling water supplied from the plunger rod 9 can flow through the plunger sleeve 8, and the plunger main body 13. And a distal end member 14 fixed to the plunger main body 13 so as to be exposed to the outside from the distal end thereof.

  The plunger body 13 has a cylindrical sliding surface 15 having a predetermined length that is in sliding contact with the inner surface of the plunger sleeve 8 and a size that does not protrude from the sliding surface 15 in the direction perpendicular to the axis, and is formed on the outer periphery on the proximal end side. A tool hook 16, a connection hole 17 that opens at the base end and is drilled toward the tip and is connected and fixed to the plunger rod 9, and opens at the tip so as to communicate with the connection hole 17, and the tip member 14 is fixedly attached. And mounting holes 18 are provided. The connection hole 17 is formed with an internal thread portion 17a that is screwed with an external thread portion (not shown) at the tip of the plunger rod 9 on the inner peripheral surface thereof. In this example, the shaft cores of the connection hole 17 and the attachment hole 18 are arranged substantially coaxially with the shaft core of the outer sliding surface 15. In addition, the communication space 12 is formed by the connection hole 17 and the attachment hole 18. Furthermore, although illustration is omitted, the plunger rod 9 and the plunger main body 13 are watertightly connected using a known technique.

  The mounting hole 18 of the plunger body 13 includes a large-diameter portion 18a that opens to the distal end, and a small-diameter portion 18b that continues from the proximal end side of the large-diameter portion 18a and penetrates to the connection hole 17, and the large-diameter portion 18a. And the small-diameter portion 18b form a stepped hole in which a cut portion 18c is formed. A female screw portion 18 d for fixing the tip member 14 is formed on the inner peripheral surface of the large diameter portion 18 a of the mounting hole 18.

  The tip member 14 closes the opening on the tip end side of the mounting hole 18 and is exposed to the outside, and a cylinder in which a male screw portion 19 is formed on the outer periphery to be screwed with a female screw portion 18d formed in the large diameter portion 18a of the mounting hole 18. The exposed portion 20 has a shape, and a protruding portion 21 that protrudes in the axial direction from the proximal end side of the exposed portion 20 and has an outer shape that can be inserted into the small diameter portion 18b of the mounting hole 18, and has an outer shape as illustrated. The shape corresponds to the shape of the inner surface of the mounting hole 18 of the plunger body 13.

  Further, the tip member 14 is provided with an annular groove-like seal holding portion 23 that holds a seal member 22 that seals the space between the plunger main body 13 and the tip member 14 on the outer periphery of the protruding portion 21. A blind hole 24 having a predetermined depth is formed on the axial center of the projecting portion 21 from the base end side, and the projecting portion 21 is formed in a cylindrical shape by the blind hole portion 24. The depth of the blind hole 24 is appropriately set according to the pressing force applied to the plunger 10 during die casting, the cooling efficiency required for the biscuit portion 7a, and the like.

  In the present embodiment, the seal member 22 is an O-ring, and the seal holding portions 23 are provided at two locations in the axial direction, and the two seal members 22 are provided. There may be one or three or more. Further, a tool engaging portion 25 that can be engaged with a predetermined tool is provided at the bottom of the blind hole portion 24, and by engaging the predetermined tool with the tool engaging portion 25, the tip member 14 is engaged. Can be easily attached to and detached from the plunger main body 13.

  In addition, the plunger 10 of the present embodiment uses carbon steel such as S50C or tool steel such as SKD as the material of the plunger main body 13, and at least the sliding surface 15 improves wear resistance. Therefore, known surface hardening treatments such as induction hardening, carburizing hardening, nitriding treatment, and thermal spraying treatment with an appropriate alloy such as nickel, cobalt, chromium, etc. are performed. Further, as the material of the tip member 14, a metal material having a high thermal conductivity such as a copper alloy such as beryllium copper is used, and a material having a higher thermal conductivity than the plunger body 13 is used. In this example, beryllium is used. Copper alloy is used.

  Next, the operation of the plunger 10 of this embodiment will be described. In the plunger 10, the distal end member 14 is disposed so that the protruding portion 21 faces the mounting hole 18 of the plunger main body 13, and the plunger 10 is inserted into the mounting hole 18. Are rotated relative to each other so that the female threaded portion 18d of the large diameter portion 18a and the male threaded portion 19 of the exposed portion 20 are screwed together, and the distal end of the exposed portion 20 is in contact with the stepped portion 18c of the mounting hole 18. The member 14 can be assembled by screwing.

  At that time, the protruding portion 21 of the tip member 14 is inserted into the small diameter portion 18b, and the seal member 22 held by the seal holding portion 23 on the outer periphery of the protruding portion 21 contacts the inner peripheral surface of the small diameter portion 18b. Then, the seal member 22 seals the space between the plunger main body 13 and the tip member 14 in a watertight manner. By attaching the assembled plunger 10 to the tip of the plunger rod 9, it is used in the die casting machine 1. In this example, the tip of the plunger main body 13 and the tip of the tip member 14 are shown to be substantially flush with each other, but the tip member 14 may be protruded or retracted.

  The plunger 10 attached to the die casting machine 1 is supplied with cooling water into the flow space 12 of the plunger main body 13 through the plunger rod 9 to cool the plunger main body 13 from the inside, and FIG. ), The blind hole 24 of the tip member 14 communicates with the circulation space 12, so that the cooling water supplied to the circulation space 12 is also supplied into the blind hole 24, and the tip member 14 Thus, the temperature of the seal member 22 is suppressed from being increased.

  In addition, the plunger 10 attached to the die casting machine 1 presses the molten metal supplied into the plunger sleeve 8 and injects it into the cavity 6 during die casting, and the tip member 14 is exposed at the tip. Since the tip member 14 made of a metal material having a high thermal conductivity is in direct contact with the molten metal of the biscuit portion 7a, the biscuit portion 7a is efficiently cooled by the cooling water via the tip member 14, and the biscuit portion 7a is solidified. The cycle time in die casting can be shortened by shortening the time.

  Thus, according to the die-casting plunger 10 of the present embodiment, the tip member 14 made of a metal material having high thermal conductivity is exposed from the tip of the plunger body 13 and is in contact with the cooling water supplied into the plunger body 13. In this way, the plunger body 13 is fixed to the tip of the plunger body 13, thereby increasing the thermal conductivity of the tip of the plunger 10, improving the cooling efficiency of the biscuit portion 7 a, and shortening the solidification time of the biscuit portion 7 a. Thus, the cycle time in die casting can be shortened and the productivity can be improved.

  Further, the tip member 14 is made of a metal material having high thermal conductivity, and it becomes possible to increase the cooling efficiency without increasing the amount of heat transfer by reducing the thickness of the tip like conventional plungers. Since it is not necessary to reduce the wall thickness, the cooling efficiency of the biscuit portion 7a can be increased while maintaining the rigidity of the plunger 10, and it can also be used for die casting with a high pressing force against the molten metal.

  Further, since only a relatively expensive metal material with high thermal conductivity is used for only the tip member 14 fixed to the tip of the plunger 10, it is possible to suppress an increase in the cost of the plunger 10 and to increase the plunger body. By using an inexpensive and excellent wear resistance material for the plunger 13, the plunger 10 having a high cooling efficiency and an excellent wear resistance can be realized.

  Further, since the tip member 14 is fixed in a watertight manner via the plunger main body 13 and the seal member 22, it is possible to prevent the cooling water from leaking between the plunger main body 13 and the tip member 14. It is possible to prevent the occurrence of problems due to water leakage. Further, since the seal member 22 is provided on the outer periphery of the protruding portion 21 provided with the blind hole portion 24 to which the cooling water is supplied, and the seal member 22 is disposed at a position where it is easily cooled by the cooling water. Thus, it is possible to prevent the sealing member 22 from being deteriorated or burnt down by the heat of the molten metal, and to maintain a good sealing effect.

  Furthermore, since the plunger main body 13 and the tip member 14 are detachably fixed by screw connection, for example, when the plunger 10 is discarded, the plunger main body 13 and the tip member 14 made of different materials can be easily arranged. It can be decomposed, and the cost for disposal can be reduced. In addition, when either the plunger body 13 or the tip member 14 is consumed, the plunger body 13 and the tip member 14 are disassembled, the worn one is replaced, and the usable one is reused to apply to the plunger 10. Cost can be reduced.

  The best embodiment for carrying out the present invention has been described above, but the present invention is not limited to this embodiment, and the scope of the present invention is not deviated from the following, as shown below. Various improvements and design changes are possible.

  That is, in this embodiment, the plunger main body 13 and the inner periphery of the small diameter portion 18b are arranged between the outer periphery of the protrusion 21 and the inner periphery of the small diameter portion 18b by the seal member 22 held by the seal holding portion 23 formed on the outer periphery of the protrusion 21. Although the tip member 14 and the tip member 14 are shown to be watertight, the present invention is not limited to this. For example, as shown in FIG. 4, the protruding portion 21 is made shorter than the small diameter portion 18b and the proximal end of the small diameter portion 18b. Further, an annular seal contact portion 26 having a smaller diameter may be provided on the side, and the seal member 22 may be disposed between the end portion of the projecting portion 21 and the seal contact portion 26. Similar effects can be obtained. In addition, the code | symbol similar to the above is attached | subjected about the same part of a structure, and detailed description is abbreviate | omitted.

  Moreover, in this embodiment, although what fixed by the screw coupling between the large diameter part 18a of the plunger main body 13 and the exposed part 20 of the front-end | tip member 14 was shown, it is not limited to this, For example, a plunger main body 13 may be screw-coupled between the small-diameter portion 18b and the protruding portion 21 of the tip member 14, or the screw joint may be abolished and the tip member 14 may be press-fitted and fixed to the plunger body 13. The same effect as the above can be exhibited.

  Furthermore, in this embodiment, although the thing provided with the tool engaging part 25 in the bottom part of the blind hole part 24 was shown, it is not limited to this, For example, let the internal diameter shape of the blind hole part 24 be a polygonal shape. Thus, the blind hole 24 itself may be used as the tool engaging portion, or the tool engaging portion may be formed on the outer periphery of the protruding portion 21 similarly to the tool hooking portion 16 of the plunger main body 13. The effect of this can be achieved.

It is sectional drawing which shows schematic structure of the die-casting machine using the plunger for die-casting of this invention. (A) is sectional drawing of the plunger for die-casting which is one Embodiment of this invention, (B) is a perspective view of the plunger for die-casting shown to (A). (A) is an exploded sectional view of the plunger for die casting shown in FIG. 2, and (B) is an exploded perspective view of the plunger for die casting shown in (A). It is sectional drawing of the plunger for die-casting which is embodiment of this invention different from FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Plunger 12 Flow space 13 Plunger main body 14 End member 15 Sliding surface 16 Tool hook part 17 Connection hole 17a Female thread part 18 Mounting hole 18a Large diameter part 18b Small diameter part 18c Cut part 18d Female thread part 19 Male thread part 20 Exposed part 21 Protrusion part 22 seal member 23 seal holding part 24 blind hole part 25 tool engaging part 26 seal contact part

Claims (1)

A die-casting plunger that is inserted into a sleeve to which molten metal is supplied and is capable of pressing the supplied molten metal, and is supplied with cooling water.
A cylindrical sliding surface that is in sliding contact with the inner surface of the sleeve, a connection hole that is smaller in diameter than the sliding surface, opens at the proximal end, is drilled toward the distal end, and the distal end of the plunger rod is connected and fixed; large diameter portion and a small diameter portion and the Bei Barcelo plunger body mounting hole that is a stepped hole by penetrating from the base end side of the large diameter portion to more the connection holes than the diameter of the sliding surface open to the tip diameter When,
A columnar exposed portion that closes the distal end opening of the mounting hole of the plunger body and is exposed to the outside and inserted into the large diameter portion, and a protrusion that protrudes from the proximal end side of the exposed portion and is inserted into the small diameter portion A distal end member made of a metal material that is fixed to the plunger main body and has a higher thermal conductivity than the plunger main body.
A seal member for watertightly sealing between the plunger main body and the tip member at the position of the protruding portion of the tip member ;
The distal end member is attached to the mounting hole of the plunger main body, and in the state where the plunger rod is connected to the connection hole, there is a flow space in which cooling water supplied from the plunger rod can flow. Die casting plunger.

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