JP7578513B2 - Die casting equipment and die casting method - Google Patents

Description

The present invention relates to a die casting device and a die casting method, and in particular to a die casting device equipped with a pressurizing means for pressurizing the runner of a die casting mold, and a die casting method performed using the die casting device.

Conventionally, a die casting device has been known 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 device, it is possible to improve the quality of the die cast product formed in the cavity by pressurizing the molten metal in the runner with the second pressurizing means.

JP 2011-224650 A

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 portion of the die-cast product that has 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) to prevent backflow of the molten metal and improve the feeder effect, and as a result, 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 die that has been opened, there is a risk of damage or the product falling, and there is room for improvement.

The present invention was made in consideration of the problems existing in the conventional technology described above, and its purpose is to provide a die casting device 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 product when the die cast product is removed from the mold.

The present invention will be described below. Note that, to facilitate understanding of the present invention, reference numbers of the attached drawings are given in parentheses, but this does not mean that the present invention is limited to the illustrated form.

The die-casting device (1) according to the present invention is a die-casting device (1) comprising a die-casting die (10) defining a cavity (53) and a runner (50 (50A, 50B) ) communicating with the cavity (53), a first pressurizing means (24, 25) for filling molten metal into the cavity (53), and a second pressurizing means (40, 41, 43) for pressurizing the molten metal in the runner (50 (50B)), the second pressurizing means (40, 41, 43) comprising a pressurizing rod (43) moving forward and backward in a direction substantially perpendicular to a mold opening direction of the die-casting die (10), and the injection of the molten metal into the cavity (53) by the first pressurizing means (24, 25) is performed by a pressurizing rod (43) moving forward and backward in a direction substantially perpendicular to a mold opening direction of the die-casting die (10). and the second pressurizing means (40, 41, 43) pressurizes the molten metal in the runner (50 (50B)), so that a hollow portion (64) is formed in a runner portion (63) of a die-cast product (60) solidified in the runner (50 (50B)) by the advancement of the pressurizing rod (43), a drawn portion ( 66) having a reduced diameter is formed on at least a part of the outer periphery of the runner portion (63) at the location where the hollow portion (64) is formed, and the runner (50 (50B)) is formed so that ribs (65 (65a, 65b) ) are formed in the drawn portion (66).

In addition, in the die-casting device (1) according to the present invention, it is preferable that the ribs (65 (65a, 65b)) have a shape that extends parallel or perpendicular to the demolding direction of the fixed die (20) and movable die (30) that constitute the die-casting mold (10).

Furthermore, in the die casting apparatus (1) according to the present invention, the ribs (65 (65a, 65b)) can be formed extending in substantially the same direction as the advancing direction of the pressure rod (43) and formed over the entire length of the drawn shape portion (66).

Furthermore, in the die casting apparatus (1) of the present invention, the cross-sectional thickness of the rib (65 (65a, 65b)) can be made thinner than the cross-sectional thickness of the portion of the hollow portion (64) where the drawn portion (66) is formed.

The die casting method according to the present invention is characterized in that die casting is performed using any of the die casting devices (1) described above.

Furthermore, in the die-casting apparatus (1) of the present invention, the runners (50 (50A, 50B)) include a first runner (50A) extending in a direction having a slight inclination angle with respect to the mold opening direction of the die-casting mold (10), and a second runner (50B) extending in a direction approximately perpendicular to the mold opening direction of the die-casting mold (10), and the tip surface of the tip portion (43A) of the pressure rod (43) can be formed as an inclined surface whose angle is approximately the same as the inclination angle of the first runner (50A).

Furthermore, in the die casting apparatus (1) of the present invention, the runner (50 (50A, 50B)) can be formed so that the drawn shape portion (66) is formed as an inclined recess having approximately the same angle as the inclination angle of the first runner (50A).

The present invention provides a die casting device and a die casting method that form a hollow portion in the runner of a die cast product by pressurizing the molten metal in the runner, and that does not cause problems such as breakage or product dropping when the die cast product is removed from the mold.

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. 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. 1 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 this embodiment. FIG. This is a cross-sectional view showing the cross section of line B-B' in Figure 3. 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 a 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). 1A to 1C are diagrams showing an example of the shape 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. 5A to 5C are diagrams for explaining an example of operation control of the die casting device according to the present embodiment.

Below, preferred embodiments for carrying out the present invention will be described 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.

The die-casting device 1 according to one embodiment of the present invention will be described with reference to Figures 1 and 2. Here, Figure 1 is a cross-sectional view showing the die-casting device according to this embodiment with the pressure rod in the retracted position. Also, Figure 2 is a cross-sectional view showing the die-casting device according to this embodiment with the pressure rod in the advanced position.

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 the first pressurizing means according to the present invention.

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 arrows 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 with 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 approximately perpendicular to the axial direction of the injection sleeve 23. The first runner 50A is defined by the injection sleeve 23 arranged 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.

A hydraulic cylinder 40 is fixed to the diverter 33 via a bracket (not shown). A pressure rod 43 is connected to the piston rod 41 of the hydraulic cylinder 40 via a coupling 42. The pressure rod 43 is inserted into the through hole 34 formed in the diverter 33, and the tip 43A of the pressure rod 43 blocks the upper opening 34A of the through hole 34. The pressure rod 43 can be advanced and retreated in a direction approximately perpendicular to the mold opening direction of the die casting mold 10 by the operation of the hydraulic cylinder 40. When the hydraulic cylinder 40 is operated, it 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 the second pressure means according to the present invention.

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 to correspond to the cross-sectional shape of the tip 43A of the pressure rod 43, and the circumferential gap between the surface 51A that defines 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 riser 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 filling of the molten metal into the cavity 53 is complete, 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.

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 portion, the first runner portion, and the second runner portion, 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 essential configuration of the die-cast product manufactured by the die-casting device, and the sub-diagram (a) in the figure shows the shape of the die at the location where the biscuit portion, the first runner portion, and the second runner portion, which are parts of the die-cast product, are molded, and the sub-diagram (b) shows a part of the die-cast product molded by the die shown in the sub-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 produced 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.

First, referring to FIG. 3, the shapes of the biscuit portion 61, the first runner portion 62, and the second runner portion 63, which are part of the die-cast product 60 manufactured by the die-casting device 1 according to this embodiment, will be described.

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.

The second runner 50B is an area that extends in a direction that is approximately perpendicular to the axial direction of the injection sleeve 23, and the first runner 50A is an area 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 that is formed extending in a direction that is approximately perpendicular to the axial direction of the injection sleeve 23.

As described above, the pressure rod 43 of this embodiment can be advanced and retreated in a direction approximately 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.

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-removal 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 lower side of the paper is the fixed mold 20, the upper side of the paper is the movable mold 30, and the movable mold 30 can move 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'. And, 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-removal 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-removal direction of the fixed mold 20 and the movable mold 30 are formed. By giving the ribs 65 (65a, 65b) of this embodiment this shape, it is possible to obtain a die-cast product shape that does not impede the mold opening operation of the die-casting mold 10.

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 is a risk of the die-cast product being damaged or falling off when it is 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.

In addition, in this embodiment, as shown in FIG. 3, a drawn portion 66 is formed at the 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 on the second runner portion 63 are omitted from the illustration.

As shown in FIG. 5(b), the die-cast product 60 of this embodiment is formed with a drawn-shape portion 66, which is the 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-shape portion 66 is to obtain the effect of suitably preventing backflow of the molten metal when the pressure rod 43 enters the second runner 50B and pressurizes the molten metal. And, as shown in FIG. 5(a), this drawn-shape 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-shape portion 66 is formed. By forming the drawn-shape portion 66 on the second runner portion 63 constituting the die-cast product 60 of this embodiment, it is possible to realize a die-casting device 1 that can suitably prevent backflow of the molten metal when the pressure rod 43 pressurizes the molten metal.

Furthermore, in this embodiment, the shape of the tip 43A of the pressure rod 43 is improved. That is, as shown in FIG. 6, the angle of the tip surface of the tip 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, while 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 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.

The drawn shape portion 66 described with reference to FIG. 5 can also be formed as an inclined recess having the same angle as the inclination angle of the first runner portion 62, as shown in FIG. 6, in the same manner as the tip surface of the tip portion 43A of the pressure rod 43. 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, making it possible to obtain a die-cast product 60 of high quality.

Furthermore, in this embodiment, 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, has also been improved. That is, in the die casting method of this embodiment, as shown in FIG. 7, the pressurization 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 are controlled: time (mSec), valve opening (%), and pressure (MPa). Here, the valve opening (%) indicates the operating condition of an electromagnetic valve (not shown) in the supply path of hydraulic oil to the hydraulic cylinder 40 that operates the pressure rod 43, and indicates that the operating speed of the pressure rod 43 can be controlled by controlling the valve opening (%) of the electromagnetic valve (not shown).

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 preferably 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, so that 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.

The above describes a preferred embodiment of the present invention, but 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.

In other words, the operation control method of the pressure rod 43 according to the embodiment shown in Fig. 7 controls the pressurization operation of the molten metal by the pressure rod 43 in five stages from the first speed to the fifth speed, and controls three conditions: time (mSec), valve opening (%), and pressure (MPa). 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.

It is clear from the claims that such modifications or improvements are also included within the technical scope of the present invention.

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 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 drawn shape portion.

Claims (7)

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;
The second pressure means includes a pressure rod that advances and retreats in a direction substantially perpendicular to a mold opening direction of the die casting mold,
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 portion of the die-cast product solidified in the runner by the advancement of the pressurizing rod,
A die casting apparatus, characterized in that the runner is formed so that a drawn portion having a reduced diameter is formed on at least a part of the outer periphery of the location where the hollow portion is formed in the runner portion, and a rib is formed on the drawn portion. 2. The die casting apparatus according to claim 1,
A die casting apparatus, characterized in that the rib has a shape extending parallel or perpendicular to the demolding direction of the fixed and movable dies that constitute the die casting mold. The die casting apparatus according to claim 1 or 2,
The die casting device is characterized in that the rib is formed to extend in substantially the same direction as the advancing direction of the pressure rod and is formed over the entire length of the drawn portion. The die casting apparatus according to claim 1 or 2,
A die casting apparatus, characterized in that a thickness in a cross-sectional direction of the rib is thinner than a thickness in a cross-sectional direction of a portion of the hollow portion where the drawn portion is formed. A die casting method characterized by performing die casting using the die casting device described in claim 1 or 2. 2. The die casting apparatus according to claim 1,
The runner includes a first runner extending in a direction having a slight inclination angle with respect to the mold opening direction of the die casting mold, and a second runner extending in a direction substantially perpendicular to the mold opening direction of the die casting mold,
A die casting apparatus characterized in that a tip surface of the tip of the pressure rod is formed as an inclined surface whose angle is approximately the same as an inclination angle of the first runner. 7. The die casting apparatus according to claim 6,
A die casting apparatus, characterized in that the runner is formed so that the drawn shape portion is formed as an inclined recess having approximately the same angle as an inclination angle of the first runner.

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