Pressure rod operation control method, die casting method

Abstract

To enhance the quality of die-cast products by preventing the backflow of molten metal and the like during pressurizing rod operation, and also to prevent segregation and solidification shrinkage defects in die-cast products by optimizing the fluidity of molten metal, thereby improving both the internal and external quality of the die-cast products.SOLUTION: An operation control method for a pressurizing rod 43 employs a die-casting apparatus 1 equipped with a second runner 50B extending in a direction substantially perpendicular to the mold-opening direction of a die-casting mold 10, causing the pressurizing rod 43 to apply pressure to the molten metal within a cavity 53 via the molten metal in the second runner 50B. In this process, multi-stage or linear control is adopted for the pressurizing operation of the pressurizing rod 43.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention provides Method for controlling the operation of a pressure rod and die casting methods, in particular, die casting apparatus equipped with a pressurizing means for pressurizing the runner of a die casting mold. A method for controlling the operation of a pressure rod used when operating the The present invention also relates to a die casting method using the die casting device. [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 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 listed below). With such a die-casting apparatus, the molten metal in the runner is pressurized by the second pressurizing means, thereby making it possible to improve the quality of the die-cast product formed in the cavity. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-224650 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the die-casting apparatus disclosed in the aforementioned Patent Document 1, the first pressurizing means injects molten metal into the cavity, and the second pressurizing means pressurizes the molten metal in the runner, forming a hollow in the runner portion of the die-cast product that has solidified in the runner as the pressurizing rod advances. At the location where this hollow portion is formed, it is necessary to reduce the clearance between the second pressurizing means and the mold (runner) to prevent backflow of molten metal and improve the feeder effect. As a result, the runner portion of the die-cast product with the hollow portion formed therein becomes thin-walled. When attempting to remove a die-cast product with such a thin-walled runner portion from the mold after it has been opened, there is a risk of damage or the product falling, leaving room for improvement.

[0005] The present invention has been made in consideration of the problems present in the prior art described above, and its object is to provide a die casting apparatus in which a hollow portion is formed in the runner portion of a die-cast product by pressurizing the molten metal in the runner, and which does not cause problems such as breakage or dropping of the die-cast product when it is removed from the mold. [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 added in parentheses, but the present invention is not limited to the illustrated forms.

[0007] The method for controlling the operation of a pressure rod according to the present invention is directed to a die-casting die (10) that defines a cavity (53) and a runner (50) that communicates with the cavity (53), a first pressurizing means (24, 25) that fills molten metal into the cavity (53), and a second pressurizing means (40, 41, 43) that pressurizes the molten metal in the runner (50), wherein the second pressurizing means (40, 41, 43) advances and retreats in a direction that is substantially perpendicular to the die-opening direction of the die-casting die (10). A method for controlling the operation of a pressure rod (43) in a die-casting device (1) equipped with the pressure rod (43), which is executed when the pressure rod (43) is used, wherein the runner (50) is equipped with a second runner (50B) extending in a direction substantially perpendicular to a mold opening direction of the die-casting mold (10), and when the pressure rod (43) pressurizes the molten metal in the cavity (53) through the molten metal in the second runner (50B), the pressurizing operation of the molten metal by the pressure rod (43) is controlled in multiple stages. When the pressurizing rod (43) pressurizes the molten metal in the cavity (53) through the molten metal in the second runner (50B), the pressurizing operation of the molten metal by the pressurizing rod (43) is performed in five stages from the first speed to the fifth speed, and the pressurizing operation of the molten metal by the pressurizing rod (43) in five stages from the first speed to the fifth speed is performed by controlling three conditions: time (mSec), valve opening (%), and pressure (MPa). In the initial stage of the operation of the pressurizing rod (43), the pressure (MPa) of the pressurizing rod (43) is set low to maximize the valve opening (%), and as the pressurizing rod (43) advances into the second runner (50B), the pressure is gradually increased while decelerating. It is characterized by the following.

[0011] The die casting method according to the present invention is Taka The die casting is performed by the die casting device (1) that operates using the pressure rod operation control method. [Effects of the Invention]

[0012] According to the present invention, in a die casting apparatus in which a hollow portion is formed in the runner portion of a die-cast product by pressurizing the molten metal in the runner, it is possible to provide a die casting apparatus and a die casting method in which problems such as breakage or product dropping do not occur when the die-cast product is removed from the mold. [Brief explanation of the drawings]

[0013] [Figure 1] 3 is a cross-sectional view showing a state in which the pressure rod is in a retracted position in the die-casting device according to the present embodiment. FIG. [Figure 2] 3 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 present embodiment. FIG. [Figure 3]FIG. 2 is an external perspective view showing the shapes of a biscuit portion, a first runner portion, and a second runner portion, which are parts of a die-cast product manufactured by the die-casting device according to the present embodiment. [Figure 4] FIG. 4 is a cross-sectional view showing a cross section along line BB' in FIG. [Figure 5] This is a schematic diagram for explaining the die-casting apparatus of this embodiment and the main configuration of the die-cast product manufactured by the die-casting apparatus. Diagram (a) in the figure schematically shows the shape of the mold where the biscuit portion, first runner portion, and second runner portion, which are parts of the die-cast product, are molded, and diagram (b) shows a part of the die-cast product molded by the mold shown in diagram (a). [Figure 6] 1A to 1C are diagrams showing examples of the shape of the biscuit portion, first runner portion, and second runner portion, which are parts of a die-cast product manufactured by the die-casting device of this embodiment, and the tip portion of a pressure rod that moves back and forth relative to the second runner portion. [Figure 7] 10A and 10B are diagrams for explaining an example of operation control of the die-casting device according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] 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 not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0015] A die-casting apparatus 1 according to one embodiment of the present invention will be described with reference to Figures 1 and 2. Figure 1 is a cross-sectional view of the die-casting apparatus according to this embodiment, showing a state in which the pressure rod is in a retracted position. Figure 2 is a cross-sectional view of the die-casting apparatus according to this embodiment, showing a state in which the pressure rod is in an advanced position.

[0016] As shown in FIG. 1, the die-casting mold 10 includes a fixed mold 20 and a movable mold 30. The fixed mold 20 is composed of 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 within the injection sleeve 23. By operating an injection cylinder (not shown) to slide the plunger tip 25 within the injection sleeve 23, molten metal such as an aluminum alloy supplied from a molten metal supply hole (not shown) of the injection sleeve 23 can be filled into a cavity 53 (described below). The plunger tip 25, plunger rod 24, and injection cylinder (not shown) constitute a first pressurizing means according to the present invention.

[0017] The movable mold 30 comprises a movable holder 31, a movable die 32, and a flow divider 33, and is movable in the direction of movement of the movable mold 30 indicated by the arrow A←→A' (the mold opening direction of the die-casting mold 10). In the mold clamped state shown in FIGS. 1 and 2, a runner 50, a gate 52, and a cavity 53 are defined inside the die-casting mold 10, and the space within 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 slightly inclined relative 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. The gate 52 and the cavity 53 are defined by the fixed die 22 and the movable die 32.

[0018] 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 retracted in a direction substantially perpendicular to the mold opening direction of the die-casting mold 10 by actuation of the hydraulic cylinder 40. When the hydraulic cylinder 40 is actuated, the pressure rod 43 advances from the retracted position shown in FIG. 1 into the second runner 50B and advances to the advanced position shown in FIG. 2. Therefore, in the die-casting apparatus 1 according to this embodiment, by advancing the pressure rod 43 into the second runner 50B, the molten metal in the cavity 53 can be pressurized via 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.

[0019] The tip 43A of the pressure rod 43 is cylindrical. The second runner 50B has a corresponding-shaped portion 51 formed in a circular shape to correspond to the cross-sectional shape of the tip 43A of the pressure rod 43. The circumferential gap between the surface 51A defining the corresponding-shaped portion 51 and the tip 43A of 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-walled portion solidified in the gap will be cut off when the die-cast product is removed. If the gap is more than 3.0 mm, the molten metal in the second runner 50B cannot be sufficiently prevented from flowing back through the gap when pressurized by the pressure rod 43, and a sufficient feeder effect cannot be achieved for 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. Therefore, 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 that defines the corresponding shape portion 51 of the second runner 50B and the tip 43A of the pressure rod 43 to 3.0 mm or less.

[0020] The basic configuration of the die-casting apparatus 1 according to this embodiment has been described above. Next, the characteristic configuration of the die-casting apparatus 1 according to this embodiment will be described using FIGS. 3 to 7. Here, FIG. 3 is an external perspective view showing the shapes of the biscuit portion, first runner portion, and second runner portion, which are parts of a die-cast product manufactured by the die-casting apparatus according to this embodiment. FIG. 4 is a cross-sectional view showing a cross section taken along line B-B' in FIG. 3. Furthermore, FIG. 5 is a schematic diagram illustrating the die-casting apparatus according to this embodiment and the main configuration of a die-cast product manufactured by this die-casting apparatus. In the figure, sub-diagram (a) schematically shows the shape of the mold where the biscuit portion, first runner portion, and second runner portion, which are parts of the die-cast product, are molded, and sub-diagram (b) shows a part of the die-cast product molded by the mold shown in sub-diagram (a). Furthermore, Fig. 6 is a diagram showing an example of the shape of the biscuit part, first runner part, and second runner part, which are parts of a die-cast product manufactured by the die-casting device according to this embodiment, and the tip part of the pressure rod that moves back and forth relative to the second runner part. Furthermore, Fig. 7 is a diagram for explaining an example of the operation control of the die-casting device according to this embodiment.

[0021] First, with reference to FIG. 3, the shapes of a biscuit portion 61, a first runner portion 62, and a second runner portion 63, which are parts of a die-cast product 60 manufactured by the die-casting apparatus 1 according to this embodiment, will be described.

[0022] As is clear from FIG. 2, the biscuit portion 61 is a portion formed in the area surrounded by the injection sleeve 23, the plunger tip 25, and the diverter 33. The first runner portion 62 is a portion formed within the first runner 50A. The second runner portion 63 is a portion formed within the second runner 50B.

[0023] The second runner 50B is a region that extends in a direction approximately perpendicular to the axial direction of the injection sleeve 23, and the first runner 50A is a region that extends in a direction that has a slight inclination angle (for example, an angle of 5° with respect to the horizontal plane) with respect to the axial direction of the injection sleeve 23 (the mold opening direction of the die-casting mold 10).Therefore, the first runner portion 62 is connected at an approximately right angle to the second runner portion 63, which is formed to extend in a direction approximately perpendicular to the axial direction of the injection sleeve 23.

[0024] As described above, the pressure rod 43 of this embodiment can be moved forward and backward in a direction substantially perpendicular to the mold opening direction of the die-casting mold 10 by operating the hydraulic cylinder 40. Therefore, when the hydraulic cylinder 40 is operated, the pressure rod 43 advances into the second runner 50B, thereby forming a hollow portion 64 in the second runner portion 63.

[0025] In this embodiment, the second runner 50B is formed so that multiple ribs 65 are formed on the outer periphery of the portion of the second runner section 63 where the hollow section 64 is formed. As shown in FIG. 4, the multiple ribs 65 are characterized by having shapes that extend parallel to or perpendicular to the mold-removal direction of the fixed mold 20 and the movable mold 30 that constitute the die-casting mold 10. That is, in FIG. 4, the fixed mold 20 is at the bottom of the page and the movable mold 30 is at the top of the page, and the movable mold 30 is movable in the movement direction of the movable mold 30 indicated by arrow A←→A' (the mold opening direction of the die-casting mold 10). In this embodiment, of the multiple ribs 65 formed on the second runner section 63, four ribs 65a are formed that extend parallel to the mold-removal direction of the fixed mold 20 and the movable mold 30, and two ribs 65b are formed that extend perpendicular to the mold-removal direction of the fixed mold 20 and the movable mold 30. By forming the ribs 65 (65a, 65b) of this embodiment in this shape, it is possible to obtain a die-cast product shape that does not hinder the die-opening operation of the die-casting die 10.

[0026] 3 and 4, in this embodiment, multiple ribs 65 are formed around the outer periphery of the second runner portion 63 at the location where the hollow portion 64 is formed. The location where the hollow portion 64 is formed in the second runner portion 63 is thin-walled, and therefore, in conventional die-cast products that do not have ribs 65, there is a risk of the die-cast product being damaged or falling off when the die-cast product is removed from the open mold. However, in this embodiment, by forming multiple ribs 65 at the thin-walled location where the hollow portion 64 is formed, the strength of the second runner portion 63 is improved, and it is possible to obtain the effect of preventing damage, falling off, and other such damage when the die-cast mold 10 is opened and the die-cast product 60 is removed.

[0027] In this embodiment, as shown in Fig. 3, a tapered portion 66 is formed at a location where the plurality of ribs 65 are formed in the second runner portion 63. Here, Fig. 5 will be referred to in order to explain the tapered portion 66 of this embodiment. Note that in Fig. 5, for the sake of convenience, the plurality of ribs 65 formed in the second runner portion 63 are not shown.

[0028] As shown in FIG. 5( b), the die-cast product 60 of this embodiment has a drawn portion 66 formed on the outer periphery of the hollow portion 64 in the second runner portion 63, the portion having a smaller diameter than the portion where the multiple ribs 65 are formed. The reason for forming this drawn portion 66 is to effectively prevent backflow of the molten metal when the pressure rod 43 enters the second runner 50B and pressurizes the molten metal. As shown in FIG. 5( a), this drawn portion 66 can be formed by forming protrusions 20a and 30a at the corresponding positions of the fixed mold 20 and the movable mold 30 where the drawn portion 66 is formed. By forming the drawn portion 66 in the second runner portion 63 constituting the die-cast product 60 of this embodiment, a die-casting apparatus 1 can be realized that effectively prevents backflow of the molten metal when the pressure rod 43 pressurizes the molten metal.

[0029] Furthermore, in this embodiment, the shape of the tip portion 43A of the pressure rod 43 is improved. Specifically, as shown in FIG. 6 , the angle of the tip surface of the tip portion 43A of the pressure rod 43 in this embodiment is an inclined surface having the same angle as the inclination angle of the first runner portion 62. In other words, in this embodiment, the second runner portion 63 is a portion formed to extend in a direction substantially perpendicular to the axial direction of the injection sleeve 23, i.e., vertically, whereas the first runner portion 62 is a portion extending in a direction having a slight inclination angle (e.g., an angle of 5° with respect to the horizontal plane) with respect to the axial direction of the injection sleeve 23 (the mold opening direction of the die-casting mold 10). Therefore, the tip surface of the tip portion 43A of the pressure rod 43 is made an inclined surface so as to have the same inclination angle as the first runner portion 62 having a slight inclination angle. By adopting such a shape, the fluidity of the molten metal pressurized by the pressure rod 43 is improved, making it possible to obtain a high-quality die-cast product 60.

[0030] 5, it is also possible to form the drawn portion 66 described using Fig. 5 as an inclined recess having the same angle as the inclination angle of the first runner portion 62, as shown in Fig. 6, similar to the tip surface of the tip portion 43A of the pressure rod 43. By forming the drawn portion 66 of this embodiment as an inclined recess having the same angle as the inclination angle of the first runner portion 62, the fluidity of the molten metal pressurized by the pressure rod 43 is improved, and it is possible to obtain a high-quality die-cast product 60.

[0031] Furthermore, in this embodiment, an improvement has also been made to the method of controlling the operation of the pressure rod 43, which pressurizes the molten metal in the cavity 53 via the molten metal in the second runner 50B. That is, in the die casting method of this embodiment, as shown in FIG. 7 , the pressurization operation of the pressure rod 43 to pressurize the molten metal is set to five stages, from first speed to fifth speed, and three conditions are controlled: time (mSec), valve opening (%), and pressure (MPa). Here, the valve opening (%) indicates the operating condition of a solenoid valve (not shown) in the supply path of hydraulic oil to the hydraulic cylinder 40 that operates the pressure rod 43, and it is shown that the operating speed of the pressure rod 43 can be controlled by controlling the valve opening (%) of the solenoid valve (not shown).

[0032] As shown in FIG. 7 , in this embodiment, the pressure of the pressure rod 43 is low and the speed (valve opening) is maximized during the initial stage of the operation of the pressure rod 43. As the pressure rod 43 advances into the second runner 50B, the pressure gradually decreases and the pressure increases. These speed and pressure changes are determined based on the solidification and shrinkage of the molten metal in the second runner 50B. By performing a die casting process using the method for controlling the operation of the pressure rod 43 shown in FIG. 7 , backflow of the molten metal during operation of the pressure rod 43 is effectively prevented, thereby improving the quality of the resulting die-cast product 60. In particular, the method of this embodiment shown in FIG. 7 optimizes the fluidity of the molten metal, preventing segregation and solidification shrinkage cavities in the resulting die-cast product 60. This results in improved internal and external quality of the die-cast product 60 compared to the prior art.

[0033] While the preferred embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the scope described in the above embodiments. Various modifications and improvements can be made to the above embodiments.

[0034] 7, the operation of the pressure rod 43 is controlled in five stages from the first speed to the fifth speed by controlling three conditions: time (mSec), valve opening (%), and pressure (MPa). By introducing linear control, for example, into this operation control method, it is possible to stably execute the control operation of the pressure rod 43.

[0035] It is clear from the claims that such modifications and improvements may also be included within the technical scope of the present invention. [Explanation of symbols]

[0036] 1 die casting apparatus, 10 die casting mold, 20 fixed mold, 20a protrusion shape, 21 fixed holder, 22 fixed die, 23 injection sleeve (sleeve), 24 plunger rod (first pressure means), 25 plunger tip (first pressure means), 30 movable mold, 30a protrusion shape, 31 movable holder, 32 movable die, 33 diverter, 34 through hole, 34A upper opening, 40 hydraulic cylinder (second pressure means), 41 piston rod (second pressure means), 42 coupling, 43 pressure rod (second pressure means), 43A tip portion, 50 runner, 50A first runner (runner), 50B second runner (runner), 51 corresponding shape portion, 51A surface, 52 gate, 53 cavity, 60 die-cast product, 61 biscuit portion, 62 First runner portion, 63 second runner portion (runner portion), 64 hollow portion, 65, 65a, 65b ribs, 66 drawing shape portion.

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; In a die casting apparatus comprising: a pressure rod that advances and retreats in a direction substantially perpendicular to a mold opening direction of the die casting mold; The runner includes a second runner extending in a direction substantially perpendicular to a mold opening direction of the die-casting mold, When the pressurizing rod pressurizes the molten metal in the cavity through the molten metal in the second runner, the pressurizing operation of the pressurizing rod on the molten metal is performed in multiple stages, When the pressurizing rod pressurizes the molten metal in the cavity through the molten metal in the second runner, the pressurizing operation of the pressurizing rod is set to five stages from a first speed to a fifth speed, The pressurizing operation of the molten metal by the pressurizing rod is performed in five stages from the first speed to the fifth speed by controlling three conditions: time (mSec), valve opening (%), and pressure (MPa), In the initial stage of the operation of the pressure rod, the pressure (MPa) of the pressure rod is reduced to maximize the valve opening (%); A method for controlling the operation of a pressure rod, characterized in that the pressure of the pressure rod is gradually increased while decelerating as the pressure rod advances into the second runner.

2. A die casting method, comprising the step of: performing die casting using the die casting device that operates using the method for controlling the operation of a pressure rod according to claim 1.

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