Pressurizing rod operation control method and 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 relates to Method for controlling the operation of a pressure rod and a die casting method, in particular, a die casting apparatus equipped with a pressurizing means for pressurizing a runner of a die casting mold. A method for controlling the operation of a pressure rod used in operating the The present invention also relates to a die casting method 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 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 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 device disclosed in the above-mentioned Patent Document 1, the first pressurizing means injects the molten metal into the cavity, and the second pressurizing means pressurizes the molten metal in the runner, so that a hollow portion is formed in the runner of the die-cast product solidified in the runner by the advancement of the pressurizing rod. In the area where this hollow portion is formed, it is necessary to reduce the clearance between the second pressurizing means and the die (runner) in order to prevent backflow of the molten metal and improve the feeder effect, and therefore the runner portion of the die-cast product in which the hollow portion is formed becomes thin-walled. When attempting to remove a die-cast product with such a thin-walled runner portion from the open die, there is a risk of damage or the product falling, and there is room for improvement.

[0005] The present invention has been made in consideration of the problems existing 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 inside the runner, which does not cause problems such as breakage or the product falling when the die cast product 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 given 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 comprises the steps of: A cavity (53) and a runner (5) communicating with the cavity (53). 0) The die-casting mold (10) defines a cavity (53), a first pressurizing means (24, 25) for filling the molten metal into the cavity (53), and the runner (5 0) and a second pressurizing means (40, 41, 43) for pressurizing the molten metal in the die casting mold (10), the second pressurizing means (40, 41, 43) including a pressurizing rod (43) that advances and retreats in a direction substantially perpendicular to the die opening direction of the die casting mold (10). The method for controlling the operation of the pressure rod (43) is executed when the pressure rod (43) is used, wherein the runner (50) is provided 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 pressure rod (43) is multi-stage or linearly controlled.

[0008] In the method for controlling the operation of a pressure rod according to the present invention, 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 pressure rod (43) can be set to five stages from a first speed to a fifth speed.

[0009] In addition, the method for controlling the operation of a pressure rod according to the present invention can be configured so that the pressurizing operation of the molten metal by the pressure rod (43) in five stages from first speed to fifth speed is executed by controlling three conditions, namely, time (mSec), valve opening (%), and pressure (MPa).

[0010] Furthermore, the method for controlling the operation of a pressure rod according to the present invention can be configured so that in an initial stage of the operation of the pressure rod (43), the pressure (MPa) of the pressure rod (43) is reduced to maximize the valve opening degree (%), and the pressure is gradually increased while decelerating as the pressure rod (43) advances into the second runner (50B).

[0011] The die casting method according to the present invention is any one of the above. The above-mentioned which operates using the pressure rod operation control method The present invention is characterized in that die casting is carried out using a die casting device (1). Effect 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 inside the runner, it is possible to provide a die casting apparatus and a die casting method which prevent problems such as breakage or the product dropping when removing the die cast product from the mold. [Brief description of the drawings]

[0013] [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] 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 apparatus according to the present embodiment. [Figure 4] 4 is a cross-sectional view showing a cross section along line BB' in FIG. [Diagram 5]FIG. 1 is a schematic diagram for explaining the die-casting apparatus of this embodiment and the main configuration of a die-cast product manufactured by the die-casting apparatus, in which sub-diagram (a) shows a schematic diagram of the shape of the mold at the location where the biscuit portion, first runner portion, and second runner portion, which are part 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). [Figure 6] 1A to 1C are diagrams showing examples of the shapes of a biscuit portion, a first runner portion, and a second runner portion, which are part of a die-cast product manufactured by the die-casting apparatus of this embodiment, and a tip portion of a pressure rod that moves back and forth relative to the second runner portion. [Figure 7] 5A to 5C are diagrams for explaining an example of operation control of the die casting device according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[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 all of the combinations of features described in the embodiments are not 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 Fig. 1 and Fig. 2. Fig. 1 is a cross-sectional view showing the die-casting apparatus according to this embodiment in a state where the pressure rod is in a retreated position. Fig. 2 is a cross-sectional view showing the die-casting apparatus according to this embodiment in a state where 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 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, 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, the plunger rod 24, and the injection cylinder (not shown) constitute a first pressurizing means according to the present invention.

[0017] 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. 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 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.

[0019] The tip 43A of the pressure rod 43 is cylindrical. 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 tip 43A of the pressure rod 43, and the circumferential gap between the surface 51A defining the corresponding shape 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 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 molten metal in the second runner 50B has good fluidity, 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 tip 43A of the pressure rod 43 to 3.0 mm or less.

[0020] 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 7. Here, Fig. 3 is an external perspective view showing the shapes of the biscuit part, the first runner part, and the second runner part, which are parts of the die-cast product manufactured by the die-casting device according to this embodiment. Also, Fig. 4 is a cross-sectional view showing a cross section of the line B-B' in Fig. 3. Furthermore, Fig. 5 is a schematic diagram for explaining the die-casting device according to this embodiment and the main configuration of the die-cast product manufactured by the die-casting device, and the divided diagram (a) in the figure shows the shape of the die at the location where the biscuit part, the first runner part, and the second runner part, which are parts of the die-cast product, are molded, and the divided diagram (b) shows a part of the die-cast product molded by the die shown in the divided diagram (a). Furthermore, Fig. 6 is a diagram showing an example of the shape of the biscuit part, the first runner part, and the second runner part, which are parts of the 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] 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 in the first runner 50A. The second runner portion 63 is a portion formed in the second runner 50B.

[0023] The second runner 50B is a region extending in a direction approximately perpendicular to the axial direction of the injection sleeve 23, and the first runner 50A is a region extending in a direction having 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), so that the first runner portion 62 is connected at an approximately right angle to the second runner portion 63, which is formed extending 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 advanced and retreated 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, and a hollow portion 64 is formed in the second runner portion 63.

[0025] In this embodiment, the second runner 50B is formed so that a plurality of ribs 65 are formed on the outer periphery of the portion where the hollow portion 64 is formed in the second runner portion 63. The plurality of ribs 65 are characterized by having a shape extending parallel or perpendicular to the mold-pulling direction of the fixed mold 20 and the movable mold 30 constituting the die-casting mold 10, as shown in FIG. 4. That is, in FIG. 4, the fixed mold 20 is at the bottom of the paper, the movable mold 30 is at the top of the paper, and the movable mold 30 is movable in the moving direction of the movable mold 30 (the mold opening direction of the die-casting mold 10) indicated by the arrow A←→A'. In this embodiment, of the plurality of ribs 65 formed in the second runner portion 63, four ribs 65a having a shape extending parallel to the mold-pulling direction of the fixed mold 20 and the movable mold 30 are formed, and two ribs 65b having a shape extending perpendicular to the mold-pulling direction of the fixed mold 20 and the movable mold 30 are formed. By forming the ribs 65 (65a, 65b) of this embodiment in such a shape, it is possible to obtain a die-cast product shape that does not impede the die-casting die 10 from opening.

[0026] As shown in Figures 3 and 4, in this embodiment, multiple ribs 65 are formed on the outer periphery of the portion of the second runner portion 63 where the hollow portion 64 is formed. In the second runner portion 63, the portion where the hollow portion 64 is formed is thin-walled, so in a conventional die-cast product in which the ribs 65 do not exist, there was a risk of the die-cast product being damaged or falling off when it was removed from the open die. However, in this embodiment, the strength of the second runner portion 63 is improved by forming multiple ribs 65 in the thin-walled portion where the hollow portion 64 is formed, and it is possible to obtain the effect of preventing damage, product falling off, and other defects from occurring even when the die-casting die 10 is opened and the die-casting product 60 is removed.

[0027] In this embodiment, as shown in Fig. 3, a drawn portion 66 is formed at a location where the multiple ribs 65 are formed in the second runner portion 63. Here, Fig. 5 is referred to in order to explain the drawn portion 66 of this embodiment. Note that in Fig. 5, for ease of explanation, the multiple ribs 65 formed in the second runner portion 63 are omitted from illustration.

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

[0029] Further, in this embodiment, the shape of the tip portion 43A of the pressure rod 43 is improved. That is, 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. That is, in this embodiment, the second runner portion 63 is a portion formed by extending in a direction substantially perpendicular to the axial direction of the injection sleeve 23, i.e., in a vertical direction, whereas the first runner portion 62 is a portion extending in a direction having 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 tip surface of the tip portion 43A of the pressure rod 43 is 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, and it is possible to obtain a die-cast product 60 having high quality.

[0030] 5, it is also possible to form the drawn shape portion 66 as an inclined recess having the same angle as the inclination angle of the first runner portion 62, as in the tip surface of the tip portion 43A of the pressure rod 43, as shown in Fig. 6. By forming the drawn shape 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 die-cast product 60 having high quality.

[0031] Furthermore, in this embodiment, an improvement was also made to the method of controlling the operation of the pressurizing 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 pressurizing operation of the molten metal by the pressurizing rod 43 is set to five stages from the first speed to the fifth speed, and three conditions, namely, time (mSec), valve opening (%), and pressure (MPa), are controlled. Here, the valve opening (%) indicates the operating condition of an electromagnetic valve (not shown) in the supply path of the hydraulic oil to the hydraulic cylinder 40 that operates the pressurizing rod 43, and indicates that the operating speed of the pressurizing rod 43 can be controlled by controlling the valve opening (%) of the electromagnetic valve (not shown).

[0032] As shown in FIG. 7, in this embodiment, the pressure of the pressure rod 43 is reduced to maximize the speed (valve opening) at the initial stage of the operation of the pressure rod 43, and the pressure is gradually increased while decelerating as the pressure rod 43 advances into the second runner 50B. The change in speed and pressure is determined according to the solidification and shrinkage of the molten metal in the second runner 50B. By performing the die casting method using the operation control method of the pressure rod 43 shown in FIG. 7, backflow of the molten metal during the operation of the pressure rod 43 is suitably prevented, and the quality of the molded die-cast product 60 is improved. In particular, according to the method of this embodiment shown in FIG. 7, the fluidity of the molten metal is optimized, and the occurrence of segregation and solidification shrinkage cavities in the molded die-cast product 60 is prevented, and the internal and external quality of the die-cast product 60 is improved compared to the conventional technology.

[0033] Although 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 control method of the pressure rod 43 according to the embodiment is such that the pressurizing operation of the molten metal by the pressure rod 43 is set to five stages from the first speed to the fifth speed, and three conditions of time (mSec), valve opening (%), and pressure (MPa) are controlled. By introducing, for example, linear control into this operation control method, it becomes possible to stably execute the control operation of the pressure rod 43.

[0035] It will be apparent from the description of the claims that such modified or improved forms may also be included within the technical scope of the present invention. [Explanation of symbols]

[0036] 1 die casting device, 10 die casting mold, 20 fixed mold, 20a protruding 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 protruding 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, 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 drawn 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 die opening direction of the die casting die, the second pressure means comprising a pressure rod that advances and retreats in a direction substantially perpendicular to a die opening direction of the die casting die; The runner includes a second runner extending in a direction substantially perpendicular to a mold opening direction of the die casting mold, A method for controlling the operation of a pressure rod, characterized in that when the pressure rod pressurizes the molten metal in the cavity through the molten metal in the second runner, the pressurizing operation of the pressure rod is multi-stage or linearly controlled.

2. A method for controlling the operation of the pressure rod according to claim 1, comprising: A method for controlling the operation of a pressure rod, characterized in that when the pressure rod pressurizes the molten metal in the cavity through the molten metal in the second runner, the pressurization operation of the pressure rod is set to five stages from a first speed to a fifth speed.

3. A method for controlling the operation of the pressure rod according to claim 2, comprising: The method for controlling the operation of a pressure rod is characterized in that the pressurization operation of the molten metal by the pressure rod is performed in five stages from first speed to fifth speed by controlling three conditions, namely, time (mSec), valve opening (%), and pressure (MPa).

4. A method for controlling the operation of the pressure rod according to claim 3, comprising: 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.

5. A die casting method, characterized in that die casting is performed by the die casting device that operates using the pressure rod operation control method described in any one of claims 1 to 4.

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