Apparatus for die casting and die casting method

Abstract

To prevent a pressurization rod from being pulled out from a die casting product solidified in a runner.SOLUTION: An apparatus 1 for die casting includes a die casting mold 10 for defining a cavity 53 and a runner 50 communicating with the cavity 53, first pressurization means 24 and 25 for filling the cavity 53 with molten metal, and second pressurization means 40, 41 and 43 for pressurizing the molten metal in the runner 50, wherein the second pressurization means 40, 41 and 43 include a cylindrical shaft-shaped second pressurization rod 43 which moves forward / backward in a direction approximately orthogonal to a mold opening direction of the die casting mold 10. The apparatus 1 for die casting starts retreat operation of the second pressurization rod 43 after mold opening of the die casting mold 10 starts after filling of the cavity 53 with the molten metal and pressurization of the molten metal in the runner 50 by the second pressurization means 40, 41 and 43 end.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a die casting apparatus and a die casting method, and more particularly to a die casting apparatus provided with a pressurizing means for pressurizing a runner of a die casting mold, and a die casting method carried out using the die casting apparatus. [Background technology]

[0002] Conventionally, there has been known a die casting apparatus that includes a die casting mold that defines a cavity and a runner that communicates with the cavity, a first pressurizing means that fills the cavity with molten metal, and a second pressurizing means that pressurizes the molten metal in the runner, the second pressurizing means including a second pressurizing rod that advances and retreats in a direction substantially perpendicular to the mold opening direction of the die casting mold (see, for example, Patent Document 1 below). With such a die casting apparatus, it is possible to improve the quality of a die cast product formed in the cavity by pressurizing the molten metal in the runner with the second pressurizing rod of the second pressurizing means. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-224650 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the die-casting apparatus disclosed in the above-mentioned Patent Document 1, there was a risk that the second pressurizing rod of the second pressurizing means, which pressurized the molten metal in the runner, would become unable to be removed from the die-cast product that had solidified in the runner, leaving room for improvement.

[0005] The present invention has been made in consideration of the problems existing in the prior art described above, and its purpose is to provide a die-casting apparatus that maintains the quality of the die-cast product molded in the cavity while avoiding problems such as the second pressure rod of the second pressure means becoming stuck in the die-cast product that has solidified in the runner, and a die-casting method using the die-casting apparatus. [Means for solving the problem]

[0006] The present invention will be described below. In order to facilitate understanding of the present invention, reference numbers in the accompanying drawings are given in parentheses, but the present invention is not limited to the illustrated forms.

[0007] The present invention relates to Ruda The die casting device (1) comprises a die casting mold (10) defining a cavity (53) and a runner (50) communicating with the cavity (53), a first pressurizing means (24, 25) for filling the cavity (53) with molten metal, and a second pressurizing means (40, 41, 43) for pressurizing the molten metal in the runner (50), wherein the second pressurizing means (40, 41, 43) includes a cylindrical second pressurizing rod (43) that advances and retreats in a direction substantially perpendicular to a mold opening direction of the die casting mold (10), and is configured such that, after filling of the molten metal into the cavity (53) and pressurization of the molten metal in the runner (50) by the second pressurizing means (40, 41, 43) are completed, and after mold opening of the die casting mold (10) is started, the retreating motion of the second pressurizing rod (43) is started.

[0008] The die casting method according to the present invention is But The present invention is characterized in that die casting is performed using a die casting device (1). Effect of the Invention

[0009] According to the present invention, it is possible to provide a die casting apparatus that maintains the quality of the die cast product molded in the cavity while preventing problems such as the second pressure rod of the second pressure means becoming stuck in the die cast product that has solidified in the runner, and a die casting method using the die casting apparatus. [Brief description of the drawings]

[0010] [Figure 1] 4 is a cross-sectional view showing a state in which the pressure rod is in a retreated position in the die casting device according to the embodiment. FIG. [Diagram 2] 4 is a cross-sectional view showing a state in which the pressure rod is in an advanced position in the die casting device according to the embodiment of the present invention. FIG. [Diagram 3] 3 is a diagram showing the shape of a pressure rod provided in the die casting device according to the embodiment. FIG. [Figure 4] FIG. 1 is a diagram for explaining the characteristic configuration of a die-casting apparatus according to this embodiment, in which (a) is a cross-sectional view showing the periphery of a pressure rod, and (b) is a cross-sectional view showing the AA line cross section in (a). [Diagram 5] FIG. 5 is a diagram showing a movable mold of the die-casting apparatus according to the present embodiment shown in FIG. 4, in which (a) is a side view seen in the mold opening direction, and (b) is a cross-sectional view showing a vertical section of the center of (a). [Figure 6] 4 is a cross-sectional view for explaining the operation of the die casting device according to the present embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Preferred embodiments for carrying out the present invention will be described below with reference to the drawings. Note that the following embodiments do not limit the inventions according to the claims, and all of the combinations of features described in the embodiments are not necessarily essential to the solution of the invention.

[0012] A basic form of a die-casting apparatus 1 according to one embodiment of the present invention will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is a cross-sectional view showing a state in which a pressure rod is in a retreated position in the die-casting apparatus according to this embodiment. Fig. 2 is a cross-sectional view showing a state in which a pressure rod is in an advanced position in the die-casting apparatus according to this embodiment.

[0013] As shown in FIG. 1, the die casting mold 10 includes a fixed mold 20 and a movable mold 30. The fixed mold 20 includes a fixed holder 21 and a fixed die 22, and an injection sleeve 23 (sleeve) is disposed in the fixed holder 21. A plunger tip 25 connected to the tip of a plunger rod 24 is disposed in the injection sleeve 23. By operating an injection cylinder (not shown) to slide the plunger tip 25 in the injection sleeve 23, it is possible to fill a molten metal such as an aluminum alloy supplied from a molten metal supply hole (not shown) of the injection sleeve 23 into a cavity 53 described later. The plunger tip 25, the plunger rod 24, and the injection cylinder (not shown) constitute a first pressurizing means according to the present invention. The plunger rod 24 constitutes a first pressurizing rod according to the present invention.

[0014] The movable mold 30 is composed of a movable holder 31, a movable die 32, and a flow divider 33, and can move in the moving direction of the movable mold 30 indicated by the arrow A←→A' (the mold opening direction of the die casting mold 10). In the mold clamping state shown in FIG. 1 and FIG. 2, a runner 50, a gate 52, and a cavity 53 are defined inside the die casting mold 10, and the space inside the injection sleeve 23 communicates with the cavity 53 via the runner 50 and the gate 52. The runner 50 includes a first runner 50A extending in a direction having a slight inclination angle with respect to the axial direction of the injection sleeve 23 (the mold opening direction of the die casting mold 10), and a second runner 50B extending in a direction substantially perpendicular to the axial direction of the injection sleeve 23. The first runner 50A is defined by the injection sleeve 23 disposed in the fixed mold 20 and the flow divider 33 of the movable mold 30. The second runner 50B has a portion defined by the injection sleeve 23 and the diverter 33, and a portion defined by the fixed die 22 and the movable die 32. In this embodiment, the portion of the second runner 50B defined by the injection sleeve 23 and the diverter 33 is formed as a cylindrical runner having a cylindrical internal space, and the portion of the second runner 50B defined by the fixed die 22 and the movable die 32 is formed as a trapezoidal runner having a trapezoidal internal space. In addition, the gate 52 and the cavity 53 are defined by the fixed die 22 and the movable die 32.

[0015] A hydraulic cylinder 40 is fixed to the diverter 33 via a bracket (not shown). A pressure rod 43 is connected to a piston rod 41 of the hydraulic cylinder 40 via a coupling 42. The pressure rod 43 is inserted into a through hole 34 formed in the diverter 33, and a tip 43A of the pressure rod 43 closes an upper opening 34A of the through hole 34. The pressure rod 43 can be advanced and retreated in a direction substantially perpendicular to the mold opening direction of the die casting die 10 by the operation of the hydraulic cylinder 40. When the hydraulic cylinder 40 is operated, the pressure rod 43 can advance from the retreated position shown in FIG. 1 into the second runner 50B and advance to the advanced position shown in FIG. 2. Therefore, in the die casting device 1 according to this embodiment, by advancing the pressure rod 43 into the second runner 50B, it is possible to pressurize the molten metal in the cavity 53 through the molten metal in the second runner 50B. The hydraulic cylinder 40, the piston rod 41, and the pressure rod 43 constitute a second pressurizing means according to the present invention. Moreover, the pressure rod 43 constitutes a second pressure rod according to the present invention.

[0016] The pressure rod 43 is shaped like a cylindrical shaft. The second runner 50B has a corresponding shape portion 51 formed in a circular shape so as to correspond to the cross-sectional shape of the pressure rod 43, and the circumferential gap between the surface 51A defining the corresponding shape portion 51 and the pressure rod 43 is set to, for example, a range of 0.5 to 3.0 mm. If the gap is less than 0.5 mm, the thin wall portion solidified in the gap will be cut off when the die-cast product is removed. If the gap exceeds 3.0 mm, the molten metal in the second runner 50B cannot be sufficiently prevented from flowing back through the gap when the molten metal in the second runner 50B is pressurized by the pressure rod 43, and a sufficient feeder effect cannot be provided to the molten metal in the cavity 53. If the fluidity of the molten metal in the second runner 50B is good, backflow is likely to occur through the gap, so when pressurizing the molten metal in the second runner 50B with the pressure rod 43 before the molten metal is completely filled into the cavity 53, it is preferable to set the gap between the surface 51A defining the corresponding shape portion 51 of the second runner 50B and the pressure rod 43 to 3.0 mm or less.

[0017] The basic configuration of the die-casting device 1 according to this embodiment has been described above. Next, the characteristic configuration of the die-casting device 1 according to this embodiment will be described with reference to Figs. 3 to 6. Here, Fig. 3 is a diagram showing the shape of the pressure rod of the die-casting device according to this embodiment. Fig. 4 is a diagram for explaining the characteristic configuration of the die-casting device according to this embodiment, in which the sub-diagram (a) is a cross-sectional view showing the periphery of the pressure rod, and the sub-diagram (b) is a cross-sectional view showing the AA line cross-section in the sub-diagram (a). Fig. 5 is a diagram showing the movable die of the die-casting device according to this embodiment shown in Fig. 4, in which the sub-diagram (a) is a side view seen in the die opening direction, and the sub-diagram (b) is a cross-sectional view showing the vertical cross-section of the center part of the sub-diagram (a). In Fig. 5(a), the pressure rod 43 is omitted for convenience of explanation. Furthermore, Fig. 6 is a cross-sectional view for explaining the operation of the die-casting device according to this embodiment.

[0018] As shown in Fig. 3, the pressure rod 43 included in the die casting apparatus 1 according to this embodiment is characterized in that a tip portion 43A thereof is tapered. The gradient formed on the tip portion 43A of the pressure rod 43 is formed at an angle of 0.1° to 0.3°. With respect to the shape of the tip portion 43A of the pressure rod 43, the diameter dimension φa of the tip portion 43A of the pressure rod 43 is set to φA, (φA-0.60mm)<φa<(φA-0.03mm) The present invention is characterized in that the following inequality is satisfied. By forming the shape of the tip 43A of the pressure rod 43 under such conditions, when the molten metal is filled in the second runner 50B and the molten metal in the second runner 50B is pressurized by the pressure rod 43, the molten metal does not get into the portion where the gradient is formed, and the pressure rod 43 can move forward and backward smoothly. In particular, with regard to the condition of "φa<(φA-0.03mm)" in the above inequality, if the dimensional difference between φA and φa is -0.03mm or less, the effect of providing the gradient becomes small, while, with regard to the condition of "(φA-0.60mm)<φa" in the above inequality, if the dimensional difference between φA and φa is -0.60mm or more, the molten metal gets into the portion where the gradient is provided, adversely affecting the smooth forward and backward movement. Note that these conditions are condition values ​​found and determined by the inventors through extensive research.

[0019] In addition, in the die casting device 1 according to the present embodiment, as shown in FIG. 4, a notch 50C is partially provided in the runner 50 in which the molten metal to be pressurized by the pressure rod 43 exists, so that the thickness dimension of the solidified metal formed by solidifying the molten metal around the pressure rod 43 is partially thinned (see FIG. 4(b) in particular). In the case of the present embodiment shown in FIG. 4, a total of two notches 50C are provided, one on each of the movable die 30 side and the fixed die 20 side. In this way, by providing two notches 50C in a part of the solidified metal surrounding the periphery of the pressure rod 43, the clinging force of the solidified metal to the pressure rod 43 is reduced, so that when the pressure rod 43 is retracted to pull out the pressure rod 43 from the die-cast product, a smooth retraction operation can be realized.

[0020] The cutout 50C of this embodiment has a trapezoidal shape in cross section, with an upper side dimension of 2 mm, a lower side dimension of 3 mm, and a vertical length dimension of about 70 mm. The cutout 50C of this embodiment can be formed by a dam 35 formed in the movable die 30 (or the fixed die 20) constituting the die-casting die 10, as shown in FIG. 5. Regarding the forming conditions of the dam 35, for example, when the stroke of the advancement and retreat of the pressure rod 43 is 80 mm, it has been revealed by the inventor's research that it is preferable to form the dam 35 from a position 10 mm above the stroke start position of the pressure rod 43 to a position of the stroke end, that is, with a length of 70 mm. By forming the cutout 50C and the dam 35 under the above-mentioned dimensional conditions, it is possible to realize a smoother retreating movement when the pressure rod 43 is retreated to pull out the pressure rod 43 from the die-cast product.

[0021] Furthermore, in the die casting device 1 according to the present embodiment, the operating conditions for the die opening operation of the die casting die 10 and the retraction operation of the pressure rod 43 are also improved. That is, as shown in FIG. 6, in the die casting device 1 according to the present embodiment, the operating conditions are adopted in which the retraction operation of the pressure rod 43 starts immediately after the die opening of the die casting die 10 starts after the filling of the molten metal into the cavity 53 and the pressurization of the molten metal in the runner 50 by the pressure rod 43 are completed. Here, in the conventional technology, the operating conditions are generally adopted in which the die opening of the die casting die 10 is performed after the retraction operation of the pressure rod 43 is completed. However, when the die casting die 10 is not opened, the die cast product is pressed by the movable die 30 and the fixed die 20, and this pressing force acts to hinder the retraction operation of the pressure rod 43. However, in this embodiment, operating conditions are adopted in which the retraction movement of the pressure rod 43 begins immediately after the die-casting mold 10 begins to open, so the pressure rod 43 can be pulled out of the die-casting product in a state in which the pressing force applied to the die-casting product by the movable mold 30 and the fixed mold 20 is released. Furthermore, the operating conditions of this embodiment do not deteriorate the time cycle for carrying out the die-casting method, and can contribute to improving product quality and equipment life while maintaining productivity.

[0022] Although the preferred embodiment of the present invention has been described above, the technical scope of the present invention is not limited to the scope described in the above embodiment. Various modifications and improvements can be made to the above embodiment. It is clear from the claims that such modifications and improvements can also be included in the technical scope of the present invention. [Explanation of symbols]

[0023] 1 die casting device, 10 die casting mold, 20 fixed mold, 21 fixed holder, 22 fixed die, 23 injection sleeve (sleeve), 24 plunger rod (first pressure means, first pressure rod), 25 plunger tip (first pressure means), 30 movable mold, 31 movable holder, 32 movable die, 33 diverter, 34 through hole, 34A upper opening, 35 weir, 40 hydraulic cylinder (second pressure means), 41 piston rod (second pressure means), 42 coupling, 43 pressure rod (second pressure means, second pressure rod), 43A tip portion, 50 runner, 50A first runner, 50B second runner (runner), 50C cutout portion, 51 corresponding shape portion, 51A surface, 52 gate, 53 cavity.

Claims

1. A die casting mold defining a cavity and a runner communicating with the cavity; A first pressurizing means for filling the molten metal into the cavity; A second pressurizing means for pressurizing the molten metal in the runner; Equipped with The second pressure means includes a cylindrical second pressure rod that advances and retreats in a direction substantially perpendicular to a mold opening direction of the die casting mold, a die casting apparatus configured such that, after the filling of the molten metal into the cavity and the pressurization of the molten metal in the runner by the second pressurizing means are completed, the die casting mold is started to be opened and then the retraction operation of the second pressurizing rod is started.

2. A die casting method, comprising the steps of: performing die casting using the die casting apparatus according to claim 1 .

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