Injection molding equipment and die-casting machines

Abstract

To provide an injector allowing for improving the component lifetime of a plunger tip.SOLUTION: An injector in an embodiment comprises a plunger rod having a plunger-rod flange, an injection-piston rod, and a coupling part for connecting the plunger rod and the injection-piston rod. The coupling part includes: a first centering pin having a first flange; a second centering pin having a second flange; a third centering pin having a third flange; a frame having a first stopper portion for restricting the movement of the first centering pin, a second stopper portion for restricting the movement of the second centering pin and a third stopper portion for restricting the movement of the third centering pin; a first elastic body for pushing the first flange against the first stopper portion; a second elastic body for pushing the second flange against the second stopper portion; and a third elastic body for pushing the third flange against the third stopper portion.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an injection device and a die-casting machine.

Background Art

[0002] A die-casting machine manufactures die-cast products by filling molten metal into a cavity in a mold clamped by a clamping device using an injection device.

[0003] In a die-casting machine, an injection sleeve connected to the cavity in the mold is provided horizontally. The injection device fills the molten metal supplied into the injection sleeve into the cavity in the mold by moving a plunger rod provided with a plunger tip at its tip forward with respect to the injection sleeve.

[0004] The plunger rod is connected to an injection piston rod using a coupling part. When the injection piston rod is driven by an injection actuator and moves forward, the plunger rod moves forward.

[0005] It is desirable that the central axis of the injection sleeve and the central axis of the plunger rod coincide. If the central axis of the injection sleeve and the central axis of the plunger rod do not coincide, the friction between the plunger tip moving in the injection sleeve and the injection sleeve increases. When the friction between the plunger tip and the injection sleeve increases, the wear of the plunger tip increases and the component life of the plunger tip decreases. Also, as the friction between the plunger tip and the injection sleeve increases, the injection operation of filling the molten metal into the mold becomes unstable and the quality of the die-cast product deteriorates.

[0006] By aligning the central axis of the injection sleeve with the central axis of the plunger rod, friction between the plunger tip moving within the injection sleeve and the injection sleeve is reduced. This reduced friction between the plunger tip and the injection sleeve reduces wear on the plunger tip, improving its lifespan. Furthermore, the reduced friction between the plunger tip and the injection sleeve stabilizes the injection operation that fills the mold with molten metal, improving the quality of the die-cast product.

[0007] Patent Document 1 describes an injection device in which a plunger rod is supported by a lower elastic support unit and left and right elastic support units provided in the coupling portion. However, in the invention described in Patent Document 1, it is difficult to align the central axis of the injection sleeve with the central axis of the plunger rod. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2015-71169 [Overview of the project] [Problems that the invention aims to solve]

[0009] The problem that this invention aims to solve is to provide an injection device that improves the lifespan of the plunger tip component and stabilizes the injection operation. [Means for solving the problem]

[0010] An injection apparatus according to one aspect of the present invention includes a plunger rod to which a plunger tip can be attached at one end and having a plunger rod flange at the other end, an injection piston rod having a piston rod flange at one end, and a coupling portion connecting the plunger rod and the injection piston rod, comprising: a first centering pin provided along the outer circumference of the plunger rod flange and having a first flange; a second centering pin provided along the outer circumference of the plunger rod flange and having a second flange; a third centering pin provided along the outer circumference of the plunger rod flange and having a third flange; and the plunger rod flange and front A frame covering the piston rod flange, comprising: a frame having a first stopper portion that restricts the movement of the first centering pin in the direction of the plunger rod flange; a second stopper portion that restricts the movement of the second centering pin in the direction of the plunger rod flange; and a third stopper portion that restricts the movement of the third centering pin in the direction of the plunger rod flange; and a coupling portion comprising: a first elastic body that presses the first flange against the first stopper portion; a second elastic body that presses the second flange against the second stopper portion; and a third elastic body that presses the third flange against the third stopper portion. The first centering pin, the second centering pin, and the third centering pin are arranged at predetermined intervals that are nearly equal in the outer circumference direction of the plunger rod flange, and with the plunger rod and the injection piston rod connected at the coupling portion, the elastic force of the first elastic body is set so that the first flange contacts the first stopper portion, the elastic force of the second elastic body is set so that the second flange contacts the second stopper portion, and the elastic force of the third elastic body is set so that the third flange contacts the third stopper portion. .

[0011] In the injection apparatus according to the above embodiment, the first elastic body, the second elastic body, and the third elastic body are preferably disc springs.

[0013] In the injection apparatus according to the above embodiment, the second centering pin and the third centering pin are provided below the first centering pin, and it is preferable that the distance between the second centering pin and the third centering pin is shorter than the distance between the first centering pin and the second centering pin, and the distance between the second centering pin and the third centering pin is shorter than the distance between the first centering pin and the third centering pin.

[0014] In the injection apparatus according to the above embodiment, the surface of the plunger rod flange facing the injection piston rod flange is preferably crowned.

[0015] In the injection apparatus according to the above embodiment, the coupling portion is mounted, and the coupling portion The direction in which the plunger rod extends It is preferable to further provide a guide rail that allows movement.

[0016] In the injection device according to the above embodiment, it is preferable that the coupling portion further includes a roller that contacts the guide rail.

[0017] An injection apparatus according to another aspect of the present invention includes a plunger rod having a plunger tip attached to one end and a plunger rod flange at the other end, an injection piston rod having a piston rod flange at one end, a coupling portion connecting the plunger rod and the piston rod, and a mounting plate on which the coupling portion is mounted. The direction in which the plunger rod extends It is preferable to include a guide rail that allows movement.

[0018] In the injection device according to the above embodiment, it is preferable that the coupling portion further includes a roller that contacts the guide rail.

[0019] A die-casting machine according to one aspect of the present invention is equipped with an injection device according to the above aspect. [Effects of the Invention]

[0020] According to the present invention, it is possible to provide an injection device that improves the lifespan of the plunger tip component and stabilizes the injection operation. [Brief explanation of the drawing]

[0021] [Figure 1] A schematic diagram showing the overall configuration of the die-casting machine according to the first embodiment. [Figure 2] A schematic cross-sectional view of the coupling section of the injection device according to the first embodiment. [Figure 3]Schematic cross-sectional view of the coupling part of the injection device according to the first embodiment. [Figure 4] Schematic cross-sectional view of the coupling part of the injection device of the comparative example. [Figure 5] Schematic cross-sectional view of the coupling part of the injection device of the comparative example. [Figure 6] Schematic cross-sectional view of the coupling part of the injection device according to a modified example of the first embodiment. [Figure 7] Schematic diagram showing the overall configuration of the die-casting machine according to the second embodiment. [Figure 8] Schematic cross-sectional view of the main part of the injection device according to the second embodiment. [Figure 9] Schematic cross-sectional view of the main part of the injection device according to the second embodiment.

Mode for Carrying Out the Invention

[0022] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0023] In this specification, as an example of hydraulic pressure, hydraulic pressure will be used for explanation. For example, as an example of a hydraulic mechanism, a hydraulic mechanism will be described, and as an example of a liquid that generates hydraulic pressure, oil will be used for explanation. Instead of hydraulic pressure, for example, water pressure can also be used. Further, in this specification, as an example of the working fluid, working oil will be used for explanation.

[0024] (First Embodiment) The injection apparatus of the first embodiment includes a plunger rod to which a plunger tip can be attached at one end and a plunger rod flange at the other end, an injection piston rod to which a piston rod flange is attached at one end, and a coupling portion connecting the plunger rod and the injection piston rod, comprising: a first centering pin provided along the outer circumference of the plunger rod flange and having a first flange, a second centering pin provided along the outer circumference of the plunger rod flange and having a second flange, a third centering pin provided along the outer circumference of the plunger rod flange and having a third flange, and the plunger rod A frame covering a flange and a piston rod flange, the frame having a first stopper portion that restricts the movement of a first centering pin in the direction of the plunger rod flange, a second stopper portion that restricts the movement of a second centering pin in the direction of the plunger rod flange, and a third stopper portion that restricts the movement of a third centering pin in the direction of the plunger rod flange; and a coupling portion including a first elastic body that presses the first flange against the first stopper portion, a second elastic body that presses the second flange against the second stopper portion, and a third elastic body that presses the third flange against the third stopper portion.

[0025] Furthermore, the die-casting machine of the first embodiment is equipped with the injection device described above.

[0026] Figure 1 is a schematic diagram showing the overall configuration of the die-casting machine according to the first embodiment. Figure 1 is a side view, including a cross-sectional view in part.

[0027] The die-casting machine 100 of the first embodiment is a cold chamber type die-casting machine.

[0028] The die-casting machine 100 includes a clamping device 10, an extrusion device 12, an injection device 14, a mold 16, and a control unit 20.

[0029] The die-casting machine 100 comprises a base 22, a fixed die plate 24, a movable die plate 26, a link housing 28, and a tie bar 30.

[0030] The die-casting machine 100 is a machine that manufactures die-cast products by injecting and filling the inside of a mold 16 (cavity Ca in Figure 1) with liquid metal (molten metal) and allowing the liquid metal to solidify inside the mold 16. The metal can be, for example, aluminum, aluminum alloy, zinc alloy, or magnesium alloy.

[0031] The mold 16 includes a fixed mold 16a and a movable mold 16b. The mold 16 is located between the clamping device 10 and the injection device 14.

[0032] The fixed die plate 24 is fixed on the base 22. The fixed die plate 24 is capable of holding the fixed mold 16a.

[0033] The movable die plate 26 is mounted on the base 22 so as to be movable in the mold opening and closing direction. The mold opening and closing direction refers to both the mold opening direction and the mold closing direction as shown in Figure 1. The movable die plate 26 is capable of holding the movable mold 16b opposite the fixed mold 16a.

[0034] The link housing 28 is mounted on the base 22. One end of the link mechanism that constitutes the clamping device 10 is fixed to the link housing 28.

[0035] The fixed die plate 24 and the link housing 28 are secured by tie bars 30. The tie bars 30 support the clamping force while it is being applied to the fixed mold 16a and the movable mold 16b.

[0036] The mold clamping device 10 has the function of opening and closing the mold 16 and clamping it.

[0037] The injection device 14 has the function of injecting molten metal into the cavity Ca of the mold 16 to fill it and pressurizing the molten metal. The injection device 14 includes an injection sleeve 40, a plunger tip 41, a plunger rod 42, a coupling part 44, an injection piston rod 46, an injection actuator 48, and a support member 49. The plunger rod 42 has a plunger rod flange 42a. The injection piston rod 46 has a piston rod flange 46a.

[0038] The injection sleeve 40 leads to the cavity Ca of the mold 16. The injection sleeve 40 extends horizontally. The injection sleeve 40 extends perpendicular to the vertical direction.

[0039] The injection sleeve 40 is, for example, a cylindrical member connected to the fixed mold 16a. The injection sleeve 40 is, for example, cylindrical in shape.

[0040] The plunger rod 42 slides within the injection sleeve 40. The plunger rod 42 extends horizontally.

[0041] A plunger tip 41 can be attached to one end of the plunger rod 42. The plunger tip 41, fixed to the plunger rod 42, slides back and forth within the injection sleeve 40. As the plunger tip 41 slides forward within the injection sleeve 40, the molten metal inside the injection sleeve 40 is pushed into the mold 16.

[0042] The plunger rod 42 pressurizes the molten metal after it has been filled into the cavity Ca of the mold 16, thereby applying pressure to the molten metal.

[0043] For example, a hot water inlet is provided at the top of the injection sleeve 40. For example, molten metal is supplied into the injection sleeve 40 from the hot water inlet by a ladle (not shown).

[0044] The coupling section 44 connects the plunger rod 42 and the injection piston rod 46. The injection piston rod 46 is driven horizontally using an injection actuator 48. The injection actuator 48 is, for example, a hydraulic cylinder.

[0045] The support member 49, for example, fixes the injection actuator 48 to the fixed die plate 24.

[0046] The extrusion device 12 has the function of pushing the manufactured die-cast product out of the mold 16.

[0047] The control unit 20 includes a control device 32, an input device 34, and a display device 36. The control unit 20 has the function of controlling the molding operation of the die-casting machine 100 using a clamping device 10, an extrusion device 12, and an injection device 14.

[0048] The input device 34 receives input from the operator. The operator can use the input device 34 to set molding conditions and other parameters of the die-casting machine 100. The input device 34 is, for example, a touch panel using a liquid crystal display or an organic EL display.

[0049] The display device 36 displays, for example, the molding conditions and operating status of the die-casting machine 100 on its screen. The display device 36 is, for example, a liquid crystal display or an organic EL display.

[0050] The control device 32 has the function of performing various calculations and outputting control commands to each part of the die-casting machine 100. The control device 32 has the function of storing, for example, molding conditions. The control device 32 controls, for example, the operation of the injection device 14.

[0051] The control device 32 is composed of, for example, a combination of hardware and software. The control device 32 includes, for example, a CPU (Central Processing Unit), semiconductor memory, and a control program stored in the semiconductor memory.

[0052] Figures 2 and 3 are schematic cross-sectional views of the coupling section of the injection device according to the first embodiment. Figure 3 is a cross-sectional view AA' of Figure 2.

[0053] The coupling portion 44 includes a frame 50, a first centering pin 52a, a second centering pin 52b, a third centering pin 52c, a first elastic body 54a, a second elastic body 54b, a third elastic body 54c, a first fixing member 56a, a second fixing member 56b, and a third fixing member 56c.

[0054] The frame 50 includes a first stopper portion 50a, a second stopper portion 50b, and a third stopper portion 50c. The first centering pin 52a includes a first flange 52ax. The second centering pin 52b includes a second flange 52bx. The third centering pin 52c includes a third flange 52cx.

[0055] The plunger rod 42 has a plunger rod flange 42a at one end to which the plunger tip 41 can be attached and at the other end opposite to it. The injection piston rod 46 has a piston rod flange 46a at one end.

[0056] The coupling section 44 connects the plunger rod 42 and the injection piston rod 46. The frame 50 covers the plunger rod flange 42a and the piston rod flange 46a. The frame 50 surrounds the plunger rod flange 42a and the piston rod flange 46a.

[0057] A predetermined clearance is provided between the frame 50 and the plunger rod 42 and plunger rod flange 42a. This clearance allows for a certain degree of movement of the plunger rod 42 and plunger rod flange 42a relative to the frame 50.

[0058] For example, there is no clearance between the frame 50 and the injection piston rod 46 and piston rod flange 46a. For example, the frame 50 and the injection piston rod 46 and piston rod flange 46a are in close contact. For example, the injection piston rod 46 and piston rod flange 46a are fixed to the frame 50 so that they do not move.

[0059] The first centering pin 52a, the second centering pin 52b, and the third centering pin 52c are provided, for example, along the outer circumference of the plunger rod flange 42a. For example, the second centering pin 52b and the third centering pin 52c are provided vertically below the first centering pin 52a.

[0060] The first centering pin 52a, the second centering pin 52b, and the third centering pin 52c have the function of centering the plunger rod 42. The first centering pin 52a, the second centering pin 52b, and the third centering pin 52c align, for example, the central axis 42x of the plunger rod 42 with the central axis 46x of the injection piston rod 46.

[0061] For example, the distance between the second centering pin 52b and the third centering pin 52c (d1 in Figure 3) is shorter than the distance between the first centering pin 52a and the second centering pin 52b (d2 in Figure 3). Furthermore, the distance between the second centering pin 52b and the third centering pin 52c (d1 in Figure 3) is shorter than the distance between the first centering pin 52a and the third centering pin 52c (d3 in Figure 3).

[0062] The first centering pin 52a is provided with a first flange 52ax. The first flange 52ax contacts the first stopper portion 50a of the frame 50. The first stopper portion 50a restricts the movement of the first centering pin 52a in the direction of the plunger rod flange 42a.

[0063] The tip of the first centering pin 52a contacts, for example, the plunger rod flange 42a.

[0064] The first elastic body 54a is provided between the first centering pin 52a and the first fixing member 56a. The first elastic body 54a is provided between the first flange 52ax and the first fixing member 56a. The first fixing member 56a is fixed to the frame 50.

[0065] The first elastic body 54a has the function of pressing the first flange 52ax against the first stopper portion 50a. With the plunger rod 42 and the injection piston rod 46 connected by the coupling portion 44, the elastic force of the first elastic body 54a is set so that the first flange 52ax contacts the first stopper portion 50a.

[0066] The first elastic body 54a is, for example, a disc spring, a leaf spring, or a coil spring.

[0067] A second flange 52bx is provided on the second centering pin 52b. The second flange 52bx contacts the second stopper portion 50b of the frame 50. The second stopper portion 50b restricts the movement of the second centering pin 52b in the direction of the plunger rod flange 42a.

[0068] The tip of the second centering pin 52b contacts, for example, the plunger rod flange 42a.

[0069] The second elastic body 54b is provided between the second centering pin 52b and the second fixing member 56b. The second elastic body 54b is provided between the second flange 52bx and the second fixing member 56b. The second fixing member 56b is fixed to the frame 50.

[0070] The second elastic body 54b has the function of pressing the second flange 52bx against the second stopper portion 50b. The elastic force of the second elastic body 54b is set so that the second flange 52bx contacts the second stopper portion 50b when the plunger rod 42 and the injection piston rod 46 are connected by the coupling portion 44.

[0071] The second elastic body 54b is, for example, a disc spring, a leaf spring, or a coil spring.

[0072] A third flange 52cx is provided on the third centering pin 52c. The third flange 52cx contacts the third stopper portion 50c of the frame 50. The third stopper portion 50c restricts the movement of the third centering pin 52c in the direction of the plunger rod flange 42a.

[0073] The tip of the third centering pin 52c contacts, for example, the plunger rod flange 42a.

[0074] The third elastic body 54c is provided between the third centering pin 52c and the third fixing member 56c. The third elastic body 54c is provided between the third flange 52cx and the third fixing member 56c. The third fixing member 56c is fixed to the frame 50.

[0075] The third elastic body 54c has the function of pressing the third flange 52cx against the third stopper portion 50c. The elastic force of the third elastic body 54c is set so that the third flange 52cx contacts the third stopper portion 50c when the plunger rod 42 and the injection piston rod 46 are connected by the coupling portion 44.

[0076] The third elastic body 54c is, for example, a disc spring, a leaf spring, or a coil spring.

[0077] Next, the operation and effects of the injection device of the first embodiment will be described.

[0078] Figures 4 and 5 are schematic cross-sectional views of the coupling section of the comparative example injection device. Figure 5 is a cross-section of BB' in Figure 4. Figures 4 and 5 are also explanatory diagrams illustrating the problems to be solved in the coupling section of the comparative example injection device.

[0079] The coupling portion 94 of the comparative example injection device differs from the coupling portion 44 of the first embodiment in that the frame 50 does not include the first stopper portion 50a, the second stopper portion 50b, and the third stopper portion 50c.

[0080] For example, in the comparative example injection device, when the plunger rod 42 and the injection piston rod 46 are connected by the coupling section 94, centering the plunger rod 42 becomes difficult, as shown in Figures 4 and 5.

[0081] For example, the central axis 42x of the plunger rod 42 and the central axis 46x of the injection piston rod 46 will no longer coincide. For example, as shown in Figure 4, the central axis 42x of the plunger rod 42 and the central axis 46x of the injection piston rod 46 will intersect at an angle.

[0082] For example, consider the case where one end of the plunger rod 42 is inserted into the injection sleeve 40. For example, due to the weight of the plunger rod 42, as shown in Figures 4 and 5, the first elastic body 54a stretches and the second elastic body 54b and the third elastic body 54c contract, causing the plunger rod flange 42a to move downward.

[0083] As a result of the downward movement of the plunger rod flange 42a, the central axis 42x of the plunger rod 42 and the central axis 46x of the injection piston rod 46 no longer coincide. For example, as shown in Figure 4, the central axis 42x of the plunger rod 42 and the central axis 46x of the injection piston rod 46 intersect at an angle.

[0084] For example, if the central axis 42x of the plunger rod 42 and the central axis 46x of the injection piston rod 46 intersect at an angle, the central axis of the injection sleeve 40 (40x in Figure 1) and the central axis 42x of the plunger rod 42 will also intersect at an angle. As a result, friction between the plunger tip 41 moving inside the injection sleeve 40 and the injection sleeve 40 increases during the injection operation of the die-casting machine.

[0085] When friction between the plunger tip 41 and the injection sleeve 40 increases, wear on the plunger tip 41 increases, reducing the lifespan of the plunger tip 41. In addition, increased friction between the plunger tip 41 and the injection sleeve 40 makes the injection operation in which molten metal is filled into the mold 16 unstable, resulting in a decrease in the quality of the die-cast product.

[0086] The injection device 14 of the first embodiment has a frame 50 that includes a first stopper portion 50a, a second stopper portion 50b, and a third stopper portion 50c. The first stopper portion 50a, the second stopper portion 50b, and the third stopper portion 50c restrict the movement of the first centering pin 52a, the second centering pin 52b, and the third centering pin 52c in the direction of the plunger rod flange 42a.

[0087] Furthermore, with the plunger rod 42 and the injection piston rod 46 connected by the coupling portion 44, the elastic force of the first elastic body 54a is set so that the first flange 52ax contacts the first stopper portion 50a. Also, with the plunger rod 42 and the injection piston rod 46 connected by the coupling portion 44, the elastic force of the second elastic body 54b is set so that the second flange 52bx contacts the second stopper portion 50b. Also, with the plunger rod 42 and the injection piston rod 46 connected by the coupling portion 44, the elastic force of the third elastic body 54c is set so that the third flange 52cx contacts the third stopper portion 50c.

[0088] Therefore, even when one end of the plunger rod 42 is inserted into the injection sleeve 40, the weight of the plunger rod 42 prevents the plunger rod flange 42a from moving downward. Thus, as shown in Figure 2, for example, the central axis 42x of the plunger rod 42 and the central axis 46x of the injection piston rod 46 coincide without being oblique.

[0089] For example, if the central axis 42x of the plunger rod 42 and the central axis 46x of the injection piston rod 46 coincide, then the central axis 40x of the injection sleeve 40 (40x in Figure 1) and the central axis 42x of the plunger rod 42 will coincide. As a result, friction between the plunger tip 41 moving inside the injection sleeve 40 and the injection sleeve 40 is reduced during the injection operation of the die-casting machine.

[0090] Reducing friction between the plunger tip 41 and the injection sleeve 40 reduces wear on the plunger tip 41, improving its lifespan. Furthermore, the reduced friction between the plunger tip 41 and the injection sleeve 40 stabilizes the injection operation that fills the mold 16 with molten metal, improving the quality of the die-cast product.

[0091] Furthermore, for example, displacement due to vibration of the plunger tip 41 during injection operation can be absorbed by the elastic force of the first elastic body 54a, the elastic force of the second elastic body 54b, and the elastic force of the third elastic body 54c.

[0092] In the comparative example coupling section 94, it is also conceivable that by individually optimizing the elastic force of the first elastic body 54a, the second elastic body 54b, and the third elastic body 54c, the downward movement of the plunger rod flange 42a due to the weight of the plunger rod 42 can be suppressed, thereby enabling centering. However, for example, the plunger rod 42 is changed along with the change of the mold 16, and the length and weight of the plunger rod 42 also change. Therefore, each time the plunger rod 42 is changed, a coupling section 94 with optimized elastic force is required, which significantly reduces the productivity of die-cast products. Furthermore, the manufacturing cost of die-cast products also increases.

[0093] In the first embodiment, the coupling portion 44, with its frame 50 including a first stopper portion 50a, a second stopper portion 50b, and a third stopper portion 50c, eliminates the need to modify the coupling portion 44 even if, for example, the length or weight of the plunger rod 42 changes. Therefore, the productivity of die-cast products does not decrease, nor does the manufacturing cost of die-cast products increase.

[0094] From the viewpoint of obtaining a large elastic force, it is preferable that the first elastic body 54a, the second elastic body 54b, and the third elastic body 54c are disc springs.

[0095] From the viewpoint of suppressing downward movement of the coupling portion 44 due to its own weight, it is preferable that the second centering pin 52b and the third centering pin 52c are provided vertically below the first centering pin 52a. Furthermore, it is preferable that the distance between the second centering pin 52b and the third centering pin 52c (d1 in Figure 3) is shorter than the distance between the first centering pin 52a and the second centering pin 52b (d2 in Figure 3). And it is preferable that the distance between the second centering pin 52b and the third centering pin 52c (d1 in Figure 3) is shorter than the distance between the first centering pin 52a and the third centering pin 52c (d3 in Figure 3).

[0096] Furthermore, it is possible to have four or more centering pins.

[0097] (modified version) The injection device of the modified embodiment differs from the injection device of the first embodiment in that the surface of the plunger rod flange facing the piston rod flange has a crowning shape.

[0098] Figure 6 is a schematic cross-sectional view of the coupling portion of an injection device of a modified example of the first embodiment. Figure 6 corresponds to Figure 2 of the first embodiment.

[0099] As shown in Figure 6, the surface of the plunger rod flange 42a facing the piston rod flange 46a has a crowned shape. The crowned shape of the surface of the plunger rod flange 42a facing the piston rod flange 46a makes it easier to absorb displacements caused by vibrations of the plunger tip 41 during injection, for example.

[0100] As described above, according to the first embodiment, an injection device and die-casting machine can be realized that improve the lifespan of the plunger tip and stabilize the injection operation.

[0101] (Second embodiment) The injection device of the second embodiment differs from the injection device of the first embodiment in that it further includes a guide rail on which the coupling part is mounted and which allows the coupling part to move horizontally. Some descriptions that overlap with the first embodiment will be omitted below.

[0102] The die-casting machine of the second embodiment is equipped with the injection device described above.

[0103] Figure 7 is a schematic diagram showing the overall configuration of the die-casting machine according to the second embodiment. Figure 7 is a side view, including a cross-sectional view in part.

[0104] The die-casting machine 200 of the second embodiment is a cold chamber type die-casting machine.

[0105] The die-casting machine 200 of the second embodiment differs from the die-casting machine 100 of the first embodiment in that the injection device 14 includes a guide rail 60.

[0106] The guide rail 60 is fixed, for example, on a support member 49. The guide rail 60 extends horizontally. The guide rail 60 is composed of, for example, two rails. The guide rail 60 supports the coupling portion 44 and allows the coupling portion 44 to move horizontally.

[0107] Figures 8 and 9 are schematic cross-sectional views of the main part of the injection device of the second embodiment. Figure 9 is a cross-section of CC' in Figure 8. Figures 8 and 9 are cross-sectional views including the coupling portion 44.

[0108] The coupling section 44 includes a frame 50, a first centering pin 52a, a second centering pin 52b, a third centering pin 52c, a first elastic body 54a, a second elastic body 54b, a third elastic body 54c, a first fixing member 56a, a second fixing member 56b, a third fixing member 56c, a support base 70, a support shaft 72, and a roller 74.

[0109] The support base 70 supports the frame 50. The frame 50 is fixed on top of the support base 70.

[0110] The roller 74 is fixed to the support base 70 by the support shaft 72. The roller 74 is placed on the guide rail 60. The roller 74 is, for example, a bearing roller.

[0111] Next, the operation and effects of the injection device of the second embodiment will be described.

[0112] For example, consider a case where the injection device does not have a guide rail 60. In this case, there is no mechanism to support the coupling portion 44 from below.

[0113] For example, consider the case where one end of the plunger rod 42 is inserted into the injection sleeve 40. In this case, for example, the plunger rod 42 and the injection piston rod 46 may bend in a direction where the bottom is convex due to the weight of the plunger rod 42, the coupling portion 44, and the injection piston rod 46.

[0114] When the plunger rod 42 and the injection piston rod 46 are curved in a direction that is convex downwards, the central axis of the injection sleeve 40 (40x in Figure 7) and the central axis 42x of the plunger rod 42 inevitably intersect at an angle. As a result, friction between the plunger tip 41 moving inside the injection sleeve 40 and the injection sleeve 40 increases during the injection operation of the die-casting machine.

[0115] When friction between the plunger tip 41 and the injection sleeve 40 increases, wear on the plunger tip 41 increases, reducing the lifespan of the plunger tip 41. In addition, increased friction between the plunger tip 41 and the injection sleeve 40 makes the injection operation in which molten metal is filled into the mold 16 unstable, resulting in a decrease in the quality of the die-cast product.

[0116] The injection device 14 of the second embodiment includes a guide rail 60 fixed on a support member 49. A coupling portion 44 is placed on the guide rail 60. The coupling portion 44 is supported from below by the guide rail 60.

[0117] Therefore, the weight of the plunger rod 42, coupling portion 44, and injection piston rod 46 prevents the plunger rod 42 and injection piston rod 46 from bending in a direction where the bottom is convex. Consequently, for example, the central axis of the injection sleeve 40 (40x in Figure 7) and the central axis 42x of the plunger rod 42 coincide. Thus, friction between the plunger tip 41 moving inside the injection sleeve 40 and the injection sleeve 40 is reduced during the injection operation of the die-casting machine.

[0118] Reducing friction between the plunger tip 41 and the injection sleeve 40 reduces wear on the plunger tip 41, improving its lifespan. Furthermore, the reduced friction between the plunger tip 41 and the injection sleeve 40 stabilizes the injection operation that fills the mold 16 with molten metal, improving the quality of the die-cast product.

[0119] Furthermore, the mechanism for moving the coupling portion 44 horizontally along the guide rail 60 is not necessarily limited to rollers 74. For example, the guide rail 60 may be formed of a bearing-type slide rail, and the support base 70 may slide along the guide rail 60.

[0120] Furthermore, the configuration of the frame 50 and centering pins placed on the support base 70 is not necessarily limited. For example, it is also possible to apply the configuration of the coupling section 94 described in the first comparative example.

[0121] As described above, according to the second embodiment, an injection device and die-casting machine can be realized that improve the lifespan of the plunger tip and stabilize the injection operation.

[0122] Embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. While parts of the injection device and die-casting machine that are not directly necessary for describing the present invention have been omitted from the description, elements related to the injection device and die-casting machine that are necessary can be appropriately selected and used.

[0123] Furthermore, all injection molding machines and molding machines that incorporate elements of the present invention and can be appropriately modified by those skilled in the art are included within the scope of the present invention. The scope of the present invention is defined by the claims and their equivalents. [Explanation of symbols]

[0124] 10 Mold clamping device 12 Extruder 14 Injection device 16 molds 16a Fixed mold 16b Movable mold 20 Control Units 22 base 24 Fixed die plate 26 Movable die plate 28 Link Housing 30 Tie Bar 32 Control device 34 Input devices 36 Display device 40 injection sleeves 41 Plunger Tip 42 Plunger Rod 42a Plunger rod flange 44 Coupling section 46 Injection piston rod 46a Piston rod flange 48 Injection Actuator 49 Support member 50 frame 50a First stopper section 50b Second stopper section 50c Third stopper section 52a First centering pin 52ax First flange 52b Second centering pin 52bx Second flange 52c Third centering pin 52cx Third flange 54a First elastic body 54b Second elastic body 54c Third elastic body 56a First fixing member 56b Second fixing member 56c Third fixing member 60 Guide Rails 70 Support stand 72 Support shaft 74 rollers 94 Coupling section 100 die-casting machines 200 die-casting machines Ca cavity

Claims

1. A plunger rod having a plunger tip attached to one end and a plunger rod flange at the other end, An injection piston rod having a piston rod flange at one end, A coupling portion connecting the plunger rod and the injection piston rod, A first centering pin having a first flange is provided along the outer circumference of the plunger rod flange, A second centering pin having a second flange is provided along the outer circumference of the plunger rod flange, A third centering pin having a third flange is provided along the outer circumference of the plunger rod flange, A frame covering the plunger rod flange and the piston rod flange, comprising: a first stopper portion that restricts the movement of the first centering pin in the direction of the plunger rod flange; a second stopper portion that restricts the movement of the second centering pin in the direction of the plunger rod flange; and a third stopper portion that restricts the movement of the third centering pin in the direction of the plunger rod flange. A first elastic body that presses the first flange against the first stopper portion, A second elastic body that presses the second flange against the second stopper portion, A third elastic body presses the third flange against the third stopper portion, A coupling section including, Equipped with, The first centering pin, the second centering pin, and the third centering pin are arranged at predetermined intervals that are nearly equal in the outer circumference direction of the plunger rod flange. An injection device characterized in that, with the plunger rod and the injection piston rod connected at the coupling portion, the elastic force of the first elastic body is set so that the first flange contacts the first stopper portion, the elastic force of the second elastic body is set so that the second flange contacts the second stopper portion, and the elastic force of the third elastic body is set so that the third flange contacts the third stopper portion.

2. The injection device according to claim 1, characterized in that the first elastic body, the second elastic body, and the third elastic body are disc springs.

3. The injection device according to claim 1, characterized in that the second centering pin and the third centering pin are provided below the first centering pin, the distance between the second centering pin and the third centering pin is shorter than the distance between the first centering pin and the second centering pin, and the distance between the second centering pin and the third centering pin is shorter than the distance between the first centering pin and the third centering pin.

4. The injection apparatus according to claim 1, characterized in that the surface of the plunger rod flange facing the piston rod flange is crowned.

5. The injection device according to claim 1, further comprising a guide rail on which the coupling portion is mounted and which allows the coupling portion to move in the direction in which the plunger rod extends.

6. The injection device according to claim 5, characterized in that the coupling portion further includes a roller that contacts the guide rail.

7. A plunger rod having a plunger tip attached to one end and a plunger rod flange at the other end, An injection piston rod having a piston rod flange at one end, A coupling portion connecting the plunger rod and the injection piston rod, A guide rail on which the coupling portion is placed and which allows the coupling portion to move in the direction in which the plunger rod extends, An injection device characterized by comprising the following:

8. The injection device according to claim 7, characterized in that the coupling portion further includes a roller that contacts the guide rail.

9. A die-casting machine characterized by being equipped with an injection device according to any one of claims 1 to 8.

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