JP4475071B2 - Molding material injection equipment - Google Patents

Description

  The present invention relates to an injection device for injecting and filling a molding material such as a molten metal into a cavity of a mold, and in particular, in an injection device such as a die casting machine, the eccentricity between a plunger sleeve and a plunger tip caused by thermal expansion or the like. The present invention relates to an injection device that can absorb inclination and improve the durability of a plunger sleeve and a plunger tip.

  Conventionally, a plunger tip of a die casting machine that injects a molten metal has a short life and is one of consumable parts. The cause is not only that the tip slides and wears out in the sleeve, but also misalignment between the injection sleeve and the injection cylinder, and an increase in sliding resistance due to deformation of the sleeve due to thermal expansion. In order to solve these problems, the coupling between the plunger rod that drives the plunger tip and the piston rod of the injection cylinder is floated using a spring to absorb the misalignment between the sleeve and the cylinder. . Further, a universal joint incorporating a spherical ball joint is interposed between the plunger tip and the plunger rod for extruding this tip, so that the plunger tip is floated.

  Conventionally, as an injection apparatus having this type of floating mechanism, in an injection pump of a hot chamber die casting machine, a plunger sleeve and a plunger tip are formed of ceramics, and a plunger rod and a piston rod of an injection cylinder are connected to each other in a connecting cylinder. One end has a ball bearing that rotatably supports a spherical ball formed at the tip of the plunger rod, and the other end rotatably supports a spherical ball formed at the tip of the piston rod. Some are connected via a universal joint having a two-point joint structure having a ball bearing (see, for example, Patent Document 1).

  Further, as a technique for improving the problems of the injection pump described in Patent Document 1, in a hot chamber type die casting machine in which a molten metal is injected from a molten metal holding furnace into a die casting machine, the plunger chip has a flat bottom surface. A joint that connects a piston rod of the injection cylinder and a plunger rod of the plunger tip by providing a hole and engaging a plunger rod with a spherical tip on the bottom surface to provide flexibility between the plunger tip and the plunger sleeve. The structure is such that the tip of the piston rod is flat and the upper end of the plunger rod is spherical (see, for example, Patent Document 2).

Japanese Utility Model Publication No. 3-12442 Registered Utility Model No. 2536660

  By the way, the joint structure of the die-casting machine described in Patent Document 2 is such that the upper end of the plunger rod and the distal end of the plunger tip are engaged by engaging a hole provided on the plunger tip with a flat bottom surface and a spherical portion at the distal end of the plunger rod. By making each of them flexible and making a shape in which an unbalanced load does not act between the plunger sleeve and the plunger tip, it is possible to prevent breakage of the tip of the plunger tip, but it has not yet been fully effective.

  That is, the arc center point of the spherical portion of the plunger rod that engages with the hole of the plunger tip is behind the center of the tip sliding surface, in other words, the length from the arc center point to the front end of the plunger tip sliding direction. Is set to be longer than the length between the arc center point and the rear end of the plunger tip in the sliding direction, and the plunger tip is pressed by the plunger rod to come into contact with the inner peripheral surface of the plunger sleeve. It is conceivable that force is concentrated locally at the time of injection and the plunger tip is consumed at an accelerated rate.

  The present invention has been made in view of such a problem. The object of the present invention is to provide a plunger tip and a plunger rod that is slid by an injection cylinder even if the plunger sleeve is eccentric due to thermal deformation or the like. An object of the present invention is to provide an injection apparatus for a molding material which can be smoothly interlocked and can perform a stable injection operation. It is another object of the present invention to provide a molding material injection apparatus that can reduce replacement work because the wear of the plunger tip is small and can be easily maintained.

  In order to achieve the above object, an injection device for a molding material according to the present invention is an injection device including a plunger tip that is pressed by a plunger rod interlocked with an injection cylinder and slides in a plunger sleeve to inject the molding material. The plunger rod has a pressing portion having a spherical surface at the tip, the plunger tip has a concave spherical portion that contacts the pressing portion, and the arc center of the pressing portion and the concave spherical portion is slid on the plunger tip. It is characterized by being located on the tip side from the center of the length in the moving direction. That is, the center of the arc of the pressing portion and the concave ball portion constituting the floating mechanism is located in the first half of the sliding length of the plunger tip. In other words, the length of the arc center and the plunger tip rear end surface is set larger than the length of the arc center of the pressing portion and the concave ball portion and the tip end surface of the plunger tip, and the length of the skirt portion of the plunger tip is large. It is characterized by.

  The molding material injection apparatus of the present invention configured as described above is configured such that the plunger tip slides on the plunger sleeve with the plunger rod even if the plunger tip and the plunger rod are eccentric or thermal deformation occurs in the plunger sleeve. When pressed in the direction, the plunger tip is prevented from swinging, so that the plunger tip can be moved smoothly and the injection operation can be stabilized. Further, since wear can be minimized by reducing the deflection of the plunger tip, the replacement timing of the plunger tip can be delayed, and maintenance and inspection work of the injection device can be reduced.

  Further, as a preferred specific aspect of the molding material injection device according to the present invention, the pressing portion having the spherical surface is characterized in that a concave groove is formed on the outer periphery so as to allow a cooling fluid to flow. . According to this configuration, the pressing portion close to the tip of the plunger tip can be efficiently cooled, the plunger tip can be prevented from thermal expansion and stable sliding can be achieved, and wear of the plunger tip can be reduced. it can.

  Furthermore, as another preferable specific aspect of the molding material injection apparatus according to the present invention, the plunger rod is positioned on the opposite side of the pressing portion with respect to the arc center, and the rear spherical surface portion is centered on the arc center. The plunger tip includes a regulating member that is in contact with the rear spherical surface portion and is opposed to the plunger rod with a gap. According to this configuration, the restricting member can come into contact with the rear spherical surface portion to prevent the plunger tip from falling off, and the swing range of the plunger rod and the plunger tip can be restricted within the interval. The plunger tip can be slid in a stable state. As a result, the injection operation of the molding material is stabilized and the wear of the plunger tip can be reduced.

  According to the molding material injection device of the present invention, the plunger tip can be stabilized even if the core is misaligned between the plunger rod for sliding the plunger tip and the injection cylinder, or the plunger sleeve is thermally deformed. It is possible to slide in such a state that a stable injection operation is possible. Further, since the wear of the plunger tip can be reduced, the life of the tip can be greatly improved, and the cycle of the replacement work can be lengthened.

  Hereinafter, an embodiment of a molding material injection apparatus according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a main part configuration diagram in which the molding material injection apparatus according to the present embodiment is applied to a cold type die casting machine, FIG. 2 is a main part configuration diagram for explaining the operation of FIG. 1, and FIG. FIG. 4 is a cross-sectional view showing the main configuration of the apparatus, and FIG. 4 is a cross-sectional view taken along line AA and part BB of FIG.

  First, a cold type die casting machine to which the injection apparatus of the present embodiment is applied will be described. 1 and 2, in the die casting machine M, a fixed platen 2 and a fixed platen 3 are fixed to a base 1, and a plurality of shafts 4 are installed between the fixed platen 2 and the fixed platen 3. A movable platen 5 is supported on the shaft 4. The movable platen 5 is moved by the mold clamping mechanism 6 so that the mold 10 is sandwiched between the movable platen 5 and the fixed platen 3. A holding furnace 7 for storing molten metal is installed in the vicinity of the base 1. The holding furnace 7 is equipped with a ladle 8 for pumping molten metal.

  The mold 10 includes a fixed mold 11 and a movable mold 12, and the die casting machine M uses a ladle 8 to melt a metal melt in the holding furnace 7 in a cavity 13 formed between the fixed mold 11 and the movable mold 12. It is a device that pumps out, injects and molds. A molding material injection device 20 is installed outside the fixed platen 3. The injection device 20 includes an injection cylinder 21, a plunger rod 30 that is interlocked with a piston rod 22 of the injection cylinder via a coupling mechanism 23, and a plunger tip 40 that is pressed by the plunger rod and slid within the plunger sleeve 24. It has.

  The plunger sleeve 24 passes through the fixed platen 3 and the fixed mold 11, and the inner space of the plunger sleeve communicates with the cavity 13 of the mold 10. The plunger sleeve 24 has a cylindrical shape, and the upper wall surface of the plunger sleeve 24 has a pouring port 25 that opens at a position where the plunger tip 40 is retracted. The molten metal in the holding furnace 7 can be poured from the pouring port 25 with the ladle 8. The injected molten metal is pressed by the plunger tip 40 slidably located in the internal space of the sleeve, and the molten metal is injected into the cavity 13 of the mold 10.

  As described above, the plunger rod 30 is connected to the piston rod 22 of the injection cylinder 21 via the coupling mechanism 23. With this configuration, the movement of the piston rod 22 of the injection cylinder 21 is transmitted to the plunger rod 30, The plunger tip 40 slides in the plunger sleeve 24. The coupling mechanism 23 enables the plunger rod 30 to slide stably even if the central axis of the piston rod 22 of the injection cylinder 21 and the central axis of the plunger rod 30 are slightly shifted or inclined. Although not shown in detail, a universal joint or the like is used.

  In the injection device 20 of the present embodiment, a plunger tip 40 is connected to the tip of a plunger rod 30 connected to a piston rod 22 of an injection cylinder 21 via a coupling mechanism 23 via a floating mechanism. Then, the plunger tip 40 is inserted into the plunger sleeve 24 by being pumped by the ladle 8 into the plunger sleeve 24 communicating with the cavity 13 of the mold 10 and supplying the molten metal and operating the injection cylinder 21. The metal melt is injected and filled into the cavity 13 by being pushed by the rod 30 and moving forward.

  Here, a floating mechanism for interlocking the plunger rod 30 and the plunger tip 40 will be described with reference to FIGS. A plunger rod 30 that is linked to the piston rod 22 of the injection cylinder 21 via a coupling mechanism 23 is formed by a hollow pipe, and a connecting member 31 is connected to the tip of the plunger rod 30 by a male screw portion 31a, and a female screw portion 31b of the connecting member. The chip pressing member 32 is connected to the front. The plunger tip 40 is pressed by the tip of the tip pressing member 32 to slide in the plunger sleeve 24. A through hole is formed in the central shaft portion of the connecting member 31. An O-ring is attached to a connecting portion of the plunger rod 30, the connecting member 31, and the tip pressing member 32 so that liquid does not leak.

  A pressing portion 33 having a spherical surface is formed at the tip (front side in the sliding direction) of the cylindrical portion of the chip pressing member 32, and this pressing portion is formed as a spherical surface having a radius R1 from the arc center C. The spherical surface of the pressing portion 33 is formed as a part of a spherical surface, but may be a hemispherical surface. Further, the tip pressing member 32 is formed with a rear spherical surface portion 34 having a radius R2 centered on the arc center C and positioned on the opposite side of the pressing portion 33 with respect to the spherical surface of the pressing portion 33 on the tip side and the arc center C. It is. Although the curvature radius of the front spherical surface and the rear spherical surface portion may be the same, in this embodiment, the curvature radius R2 of the rear spherical surface portion is set large. The chip pressing member 32 is formed with a stepped cooling hole 35 penetrating the center portion, and a pipe 36 is fitted to the step portion. And the two through-holes 37 which connect the large diameter part of a cooling hole and the outer peripheral surface of a press member are formed. In addition, concave grooves 38 are formed radially in four directions on the spherical surface of the pressing portion 33 and communicate with the cooling holes 35.

  The plunger tip 40 pressed by the tip pressing member 32 has a cylindrical shape with a closed end, and the tip pressing member 32 connected to the tip of the plunger rod 30 is inserted from the opening at the rear end. The outer surface of the closed portion at the tip forms a pressing surface for extruding the molten metal. A concave spherical portion 41 is formed on the inner surface of the pressing surface of the plunger tip 40 so as to be in contact with the spherical surface of the pressing portion 33. The arc center and radius of the concave spherical portion are the arc center C and radius of the pressing portion 33. It is consistent with R1. With this configuration, the concave ball portion 41 can swing while being in close contact with the pressing portion 33.

  At the rear end opening of the plunger tip 40, a regulating member 45 for preventing the tip pressing member 32 fixed to the tip of the plunger rod 30 from dropping off and regulating the swing range of the plunger tip 40 is mounted. The restriction member 45 includes a cylindrical portion and a flange portion, and a concave spherical surface is formed at the tip of the cylindrical portion inserted into the plunger tip 40 so as to contact the rear spherical portion 34 of the tip pressing member 32. The O-ring is attached to the concave spherical surface. That is, the pressing portion 33 having a spherical surface formed at the tip of the plunger rod 30 is in contact with the concave spherical portion 41 of the plunger tip 40, and the concave spherical surface of the restricting member 45 presses the rear spherical portion 34, whereby the plunger The plunger tip 40 is prevented from dropping from the rod 30.

  The constricted small diameter portion of the chip pressing member 32 is fitted to the inner periphery of the cylindrical portion of the regulating member 45, and the inner diameter D2 of the cylindrical portion is set larger than the outer diameter D1 of the small diameter portion, and the inner diameter D2 and the outer diameter A clearance d is formed between D1 and D1. With this clearance d, the plunger tip 40 can be swung within a predetermined angle range with respect to the tip pressing member 32 connected to the plunger rod 30. The flange portion of the restricting member 45 is in contact with the rear end surface of the plunger tip 40 with the spacer 46 in between, and is fixed with a number of fixing screws 47. As described above, the floating mechanism of the plunger tip 40 includes the plunger tip 40, the tip pressing member 32, and the regulating member 45, and the plunger tip 40 can swing within the clearance d with respect to the tip pressing member 32. Yes.

  The cooling hole 35 and the pipe 36 constitute a passage through which cooling water flows, and this passage communicates with a cooling water source (not shown). The cooling hole 35 opened at the tip of the tip pressing member 32 is closed by the concave ball portion 41 but communicates with the concave groove 38, and the concave groove 38 is formed in the space between the chip pressing member 32 and the plunger tip 40. It is open. This space communicates with the outer peripheral space of the pipe 36 through the through hole 37. In this way, the cooling water passage is configured in a double manner, the passage portion on the inner periphery of the pipe 36 constitutes a forward passage for cooling water, and the passage portion on the outer periphery of the pipe 36 constitutes a return passage for cooling water. .

  The length of the plunger tip 40 in the sliding direction is set to L, and the positions of the arc centers C of the pressing portion 33 of the tip pressing member 32 and the concave ball portion 41 of the plunger tip 40 are from the center of the sliding direction length L. Located on the tip side. That is, the front length L1 is set to be smaller than half of the sliding direction length L, and the relationship of the front length L1 <the rear length L2 is established, and the plunger tip 40 has a front length with respect to the arc center C. Is small and the length of the rear skirt portion is large, and the arc center C is located in the front half. Thus, when the plunger tip 40 is pressed by the tip pressing member 32, the plunger tip is pressed toward the front by the position of the arc center C being located closer to the front of the length L in the sliding direction. It has become.

  The operation of the molding material injection apparatus 20 of the present embodiment configured as described above will be described below. When the molding material is injected by the injection device 20 of the die casting machine M of this embodiment, the injection cylinder 21 is operated to slide the piston rod 22. The sliding of the piston rod 22 is interlocked with the plunger rod 30 via the coupling mechanism 23. As the plunger rod 30 slides, the molten metal supplied by the ladle 8 into the plunger sleeve 24 is extruded and injected into the cavity 13 in the mold 10 to be molded.

  When the plunger tip 40 is pushed out by the plunger rod 30, the spherical pressing portion 33 at the tip of the plunger rod is in contact with the concave spherical portion 41 of the plunger tip 40, and the regulating member 45 is placed on the rear spherical portion 34 of the plunger rod 30. Since the plunger tip 40 can swing within the range of the clearance d, even if the plunger rod 30 is inclined with respect to the central axis of the plunger sleeve 24 or is eccentric, the plunger sleeve 24 can be further moved. Even if is thermally deformed, the plunger tip 40 can be interlocked in a stable state, and the molding material can be stably injected.

  That is, since the arc center C of the spherical pressing portion 33 constituting the floating mechanism is located on the front side of half of the length L in the sliding direction of the plunger tip 40, the movement of the plunger rod 30 is moved to the plunger tip 40. It is transmitted smoothly. Further, since the plunger tip 40 and the plunger rod 30 are interlocked with a degree of freedom within the range of the clearance d by the floating mechanism in which the spherical surface of the pressing portion 33 and the concave spherical portion 41 contact each other, the plunger sleeve 24 When the plunger tip 40 slides inside, the rear end portion of the tip 40 is largely swung around the center of the arc so that a load in an unreasonable direction is not applied to the inner surface of the sleeve. Is prevented.

  In other words, when the arc center C of the spherical surface of the pressing portion 33 of the tip pressing member 32 connected to the distal end of the plunger rod 30 is located rearward from the center in the sliding direction of the plunger tip 40, the plunger tip 40 is When pressed by the pressing portion of the plunger rod 30, the rear end portion of the tip swings and comes into contact with the inner wall surface of the plunger sleeve 24, and the plunger tip 40 applies a load in an unreasonable direction to the plunger sleeve 24. Shina. As a result, the force is concentrated locally on the plunger tip 40, and the tip is consumed at an accelerated rate.

  As described above, in the molding material injection device 20 of the present embodiment, even if the plunger sleeve 24 is thermally deformed by the heat of the supplied molten metal, the center of the plunger sleeve 24 and the center of the plunger tip 40 are not aligned. Even if it keeps in mind, since the plunger tip 40 can slide stably with respect to the sliding of the plunger rod 30 interlocked with the injection cylinder 21, the molding material can be stably injected. Moreover, since wear of the plunger tip 40 can be minimized and the life can be extended, maintenance and inspection work of the injection device 20 can be simplified.

  The cooling water flowing in the pipe 36 is ejected from the pressing portion 33 of the tip pressing member 32, contacts the concave ball portion 41 of the plunger tip 40, and takes heat away from the plunger tip 40 through the four-direction concave grooves 38. Enter the space with 32. Then, the cooling water that has deprived of heat enters the cooling hole 35 on the outer peripheral side of the pipe 36 from the through hole 37 and is discharged. As described above, the cooling water can efficiently cool the distal end surface of the plunger tip 40 that comes into contact with the molten metal and becomes high temperature, so that the durability of the plunger tip can be improved.

  Although one embodiment of the present invention has been described in detail above, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention described in the claims. Design changes can be made. For example, the plunger tip is configured to slide while being pressed by the plunger rod, but may be configured to be pressed directly by the piston rod. Further, the cooling of the plunger tip is not limited to the cooling water, and a refrigerant may be used.

  As an application example of the present invention, this injection device can be applied not only to a cold chamber type injection device but also to a hot chamber type injection device, and also to an injection molding device such as a synthetic resin.

The principal part block diagram which shows one Embodiment which applied the injection apparatus of the molding material which concerns on this invention to the die-casting machine. The principal part block diagram for operation | movement description of FIG. Sectional drawing which shows the principal part structure of an injection apparatus. Sectional drawing which abbreviate | omitted one part along the AA sectional view and BB line of FIG.

Explanation of symbols

  M: Die casting machine, 20: Injection device, 21: Injection cylinder, 22: Piston rod, 23: Coupling mechanism, 24: Plunger sleeve, 30: Plunger rod, 32: Tip pressing member, 33: Pressing part, 34: Back Spherical surface portion, 35: cooling hole, 38: concave groove, 40: plunger tip, 41: concave spherical portion, 45: restricting member, C: arc center, d: clearance, L: sliding length of plunger tip, L1 : Front length of plunger tip (distance between arc center and plunger tip tip), L2: rear length of plunger tip

Claims (2)

An injection device comprising a plunger tip that is pressed by a plunger rod or the like interlocked with an injection cylinder, slides in a plunger sleeve, and injects a molding material,
The plunger rod is formed with a pressing portion having a spherical surface at the tip portion, the plunger tip is formed with a concave spherical portion that contacts the pressing portion, and the arc center of the pressing portion and the concave spherical portion is the center of the plunger tip. Located on the tip side from the center of the length in the sliding direction ,
The plunger rod further includes a rear spherical surface that is located on the opposite side of the pressing portion with respect to the arc center and centered on the arc center,
The plunger tip includes a cylindrical regulating member arranged so as to cover a part of the outer circumferential surface of the plunger rod with the inner circumferential surface, and the regulating member includes the rear spherical surface portion at the end thereof. A molding material injection device , wherein a rear concave spherical portion that is in contact is formed, and the inner peripheral surface is formed so as to have a clearance with respect to the outer peripheral surface of the plunger rod .   2. The molding material injection device according to claim 1, wherein the pressing portion has a concave groove formed on the outer periphery to allow a cooling fluid to flow.

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