JP2000317605A - Metallic mold pressure-casting method and apparatus thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metallic mold pressure-casting method and an apparatus thereof with which the invasion of a solidified layer of molten metal developed in a sleeve into a cavity can be restrained. SOLUTION: This metallic mold pressure-casting method is executed by pouring molten metal 8 into a sleeve 3 communicated with a cavity 2 in a metallic mold 10 and feeding the molten metal 8 into the cavity 2 by pressurizing the molten metal 8 with a plunger 4. The molten metal 8 is pressurized while gradually ripping off the solidified layer developed at pouring of the molten metal 8 into the sleeve 3 with the tip part 40 of the plunger 4 with the advance of the plunger 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die casting method for die casting or the like and a casting apparatus therefor.

[0002]

2. Description of the Related Art As a casting method excellent in dimensional accuracy, there is a mold pressure casting method in which a metal mold having a cavity is used and a molten metal is injected into the cavity by pressure. Specifically, for example, die casting, high pressure casting (squeeze casting), rheocasting, thixocasting, and the like. This mold pressure casting method is used in a wide range of fields, such as in the production of automobile parts, because it can produce cast products with high dimensional accuracy with high productivity.

[0003] An apparatus 9 for carrying out the above-mentioned mold pressure casting method comprises:
As shown in FIG. 8, a mold 10 having a cavity 2;
The sleeve 3 includes a sleeve 3 that communicates with the cavity 2 via a runner 23, and a plunger 94 that is disposed in the sleeve 3 so as to be able to advance and retreat. Then, in carrying out the above-mentioned mold pressure casting method, a molten metal 8 is injected into the sleeve 3 as shown in FIG.

[0004]

However, the above-mentioned conventional mold pressure casting method and its apparatus have the following problems. That is, as shown in FIG. 5A described later, when the molten metal 8 is poured into the sleeve 3, the molten metal in contact with the sleeve 3 is cooled and solidified, and the semi-cylindrical solidified layer 80 is formed. It is formed.

On the other hand, the conventional plunger 94 has a flat pressing surface 940 perpendicular to the pressing direction as shown in FIG. 4A described later, or a convex portion as shown in FIG. Even if it has 945, it also has a pressing surface 947 composed of a flat surface 946 that forms a right angle as described above.

Therefore, the solidified layer 80 is crushed when pressurized by the plunger 94 and is injected into the cavity 10 together with the molten metal 8 to form a broken chill layer. The incorporation of the crushed solidified layer into the casting lowers the actual strength of the casting. Further, not only such a quality problem, but also a manufacturing problem such as a decrease in meltability during casting occurs.

Conventionally, as a means for solving such a problem, there is a method in which a heat insulating powder is electrostatically applied to the inner wall of the sleeve. However, this method has a facility problem that a coating device for applying the heat insulating powder is required, and a quality problem that the heat insulating powder is mixed into the casting. It is also conceivable to heat the sleeve to a temperature higher than the freezing point of the molten metal. However, this method not only requires a heating device for the sleeve, but also has a problem that the durability of the sleeve is greatly reduced, and is disadvantageous in terms of economy.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has been made in consideration of the above circumstances. It is intended to provide such a device.

[0009]

According to a first aspect of the present invention, there is provided a mold pressure casting method in which molten metal is poured into a sleeve communicating with a cavity of a mold, and the molten metal is pressed by a plunger and fed into the cavity. When the molten metal is pressurized, the solidified layer generated when the molten metal is poured into the sleeve is removed by the tip of the plunger while the peeling of the molten metal is sequentially performed as the plunger advances. Pressure casting method characterized by pressing.

What is most remarkable in the present invention is that when the molten metal is pressurized, the solidified layer is sequentially peeled off with the tip (pressing surface) of the plunger as the plunger advances. .

As a method of sequentially peeling the solidified layer,
There is a method in which a pressing force is applied to the solidified layer by the tip of the plunger in a direction different from the forward direction, thereby dispersing the solidified layer in a direction different from the forward direction of the plunger. For example, there is a method in which the solidified layer is pressurized so as to be separated in the left-right direction with respect to the forward direction of the plunger, and the solidified layer is separated in the left-right direction to be separated. Further, for example, there is a method in which the solidified layer is pressurized so as to be scooped up in the forward direction of the plunger, and the solidified layer is separated upward to be separated.

Here, the peeling or peeling means that the tip of the plunger is crushed when the solidified layer is hard and brittle, and is mainly folded or bent when the solidified layer is soft. It means that it is peeled off from the sleeve.

Next, the operation of the present invention will be described. In the present invention, when the metal melt is pressurized, the solidified layer is sequentially peeled off as the plunger advances. As a result, the solidified layer is gradually peeled from the sleeve from the portion in contact with the plunger, while the solidified layer apart from the tip of the plunger maintains a half-cylinder shape in contact with the sleeve. Therefore, the molten metal in the sleeve is maintained in a sound state in which the side close to the cavity contains almost no broken solidified layer.

That is, in the molten metal in the sleeve at the time of pressurization, the peeled solidified layer is sequentially mixed into the tip end side of the plunger, and the peeled solidified layer is opposite to the cavity close to the cavity. It can be kept in a state where it is hardly mixed. Therefore, the molten metal sent into the cavity with the advance of the plunger is sent in a state that contains almost no crushed solidified layer.

Some of the solidified layer peeled off from the sleeve may reach the runner in front of the sleeve after the pressurization is completed, but most of the solidified layer remains in the excess molten metal remaining in the sleeve. . Therefore, the casting obtained in the cavity is excellent in quality and hardly contains a fractured chill layer. Further, it is possible to avoid deterioration of the run-off property during casting.

Conventionally, since the direction of pressing the solidified layer is the same as the direction of advance of the plunger, the solidified layer is pressed in the axial direction and crushed from any weak part. Therefore, even in the molten metal on the side near the cavity in the sleeve, the solidified layer serving as a fracture chill layer is mixed. Therefore, the solidified layer was easily mixed into the cavity. The present invention can sufficiently suppress such a phenomenon.

Therefore, according to the present invention, it is an object of the present invention to provide a mold pressure casting method capable of suppressing a solidified layer of a molten metal generated in a sleeve from entering a cavity.

Next, as in the second aspect of the present invention, it is preferable that a tip of the plunger is provided with a solidified layer separation surface for sequentially stripping the solidified layer as the plunger advances. This makes it possible to easily carry out the excellent casting method. The solidified layer peeling surface has various shapes as described later. The solidified layer peeling surface may be a surface having a function of, for example, separating the solidified layer left, right, or upward, and then dispersing while further deforming or crushing.

Next, a third aspect of the present invention is a mold having a cavity, a sleeve communicating with the cavity, and a plunger disposed in the sleeve so as to be able to advance and retreat, and to press the injected molten metal. A solidification layer formed at the tip of the plunger for removing the solidified layer formed when the molten metal is poured into the sleeve as the plunger advances. The mold pressure casting apparatus is provided with a surface.

The most remarkable point in the apparatus of the present invention is that the plunger is provided with the solidified layer peeling surface at the tip thereof. The solidified layer peeling surface is provided on the pressing surface at the tip of the plunger. The solidified layer peeling surface is a surface having a shape for sequentially stripping the solidified layer as the plunger advances when the molten metal is pressurized. For example, by pressing the solidified layer in a predetermined direction different from the forward direction of the plunger, the solidified layer can be sequentially dispersed in the predetermined direction as the plunger advances. This solidified layer separation surface can be provided in various shapes as described later.

According to the apparatus of the present invention, the above-described excellent mold pressure casting method can be easily and reliably performed, and a cast product of excellent quality can be easily obtained.

Next, as in the fourth aspect of the present invention, the solidified layer peeling surface of the plunger can be formed to have a blade for separating the solidified layer left and right. In this case, of the force applied to the plunger, a component force generated according to the angle of the blade and the peeling surface acts in a direction different from the forward direction of the plunger. Therefore, the solidified layer subjected to the component force can be deformed and crushed sequentially from the plunger side. As a result, the solidified layer can be reliably separated sequentially. The blade provided on the pressurized surface (solidified layer peeling surface) of the plunger is
Not only an acute angle but also an obtuse angle state like a blade of a blade may be used as long as it is a mountain-shaped protrusion. The solidified layer peeling surface may have at least the shape of a blade.

Further, the solidified layer peeling surface of the plunger may have a shape in which a cross section for scooping the solidified layer has an acute rake face. . In this case, the solidified layer can be easily pressed, deformed, and dispersed above the tip of the plunger. As a result, the solidified layer can be reliably separated sequentially.

Next, it is preferable that the sleeve is provided with a shutter for preventing the plunger from coming into contact with the injected molten metal before the plunger starts to move forward. In this case, the mixing of the solidified layer into the molten metal supplied to the cavity can be further suppressed.

That is, when the molten metal is poured into the sleeve, and when the tip of the plunger is in contact with the molten metal, a solidified layer of metal is also formed on the solidified layer peeling surface at the end. In this case, there is a possibility that the above-described effect of separating the solidified layer by the solidified layer separating surface may be suppressed.

On the other hand, as described above, by providing the shutter on the sleeve, the shutter can be closed and the plunger can be isolated from the molten metal when the molten metal is injected. Therefore, the solidified layer separation surface of the plunger can be maintained in a healthy state until the shutter is opened. Then, after the injection of the molten metal is completed, the shutter is opened just before the plunger is advanced. As a result, the contact time between the advancing plunger and the molten metal becomes significantly shorter than when the shutter is not provided, and the thickness of the metal solidified layer formed on the solidified layer peeling surface is also reduced. Therefore, the peeling effect of the solidified layer peeling surface can be sufficiently exerted, and the solidified layer can be sufficiently prevented from being mixed into the cavity.

Further, since the amount of the solidified layer adhering to the plunger is reduced and the peeling effect can be sufficiently exerted, the length of the so-called runner can be designed to be short, and the casting yield can be improved. Can be. In addition, as for the shutter, it is preferable that the surface in contact with the molten metal be flat or concave. Thereby, when the solidified layer solidified in contact with the shutter is separated by the solidified layer separation surface of the plunger, the separation effect can be more effectively exerted.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment A mold pressure casting method and an apparatus according to an embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the mold pressure casting apparatus 1 of this embodiment is a die casting apparatus for an aluminum alloy. This mold pressure casting apparatus 1
Is a mold 10 having a cavity 2 as shown in FIG.
And a runner 23 and a sleeve 3 communicating with the cavity 2, and a plunger 4 disposed in the sleeve 3 so as to be able to advance and retreat and pressurize the injected molten metal 8.

At the tip of the plunger 4, a solidified layer 8 formed when the molten metal 8 is injected into the sleeve 3 is formed.
0 (FIG. 3A) is provided with a solidified layer peeling surface 40 for sequentially peeling off the plunger 4 as the plunger 4 advances.

As shown in FIGS. 2A to 2C, the solidified layer peeling surface 40 of this embodiment has a blade 41 for separating the solidified layer 80 from side to side. The blade 41 has an acute angle in cross section so that the solidified layer 80 can be separated left and right from the center of the bottom. As shown in FIG. 3B, the angle is provided so as to gradually increase as the distance from the tip increases.

The solidified layer peeling surface is not limited to the plunger shown in FIG. For example, the solidified layer release surface may be a combination of two planes. That is, the intersection of the two surfaces is the blade. As shown in FIG. 2B of the first embodiment, the direction of the blade may be protruding downward, conversely protruding upward, or may be perpendicular to the pressing direction. It is basically the same in terms of the sequential peeling action of the layers.

Further, as shown in FIG.
Are provided with an inclination so that they protrude downward. Further, as shown in FIG. 3A, the blade 41 has a relatively flat upper end, which has less contact with the solidified layer 80, and has a flat shape. The cross-sectional shape of the main body of the plunger 4 is circular.

Next, in performing die casting by using the mold pressure casting apparatus 1, a molten metal 8 is first poured into the sleeve 3 as shown in FIG. As a result, the solidified layer 80 (FIG. 3A) is formed into a semi-cylindrical shape by being cooled in contact with the sleeve 3. Next, the plunger 4 is advanced to pressurize the molten metal 8, and this is fed into the cavity 2.

When the molten metal 8 is pressurized, the solidified layer 80 generated when the molten metal 8 is injected into the sleeve 3 is sequentially moved in a direction different from the advance direction according to the advance of the plunger 4. Disperse the molten metal 8
Press.

That is, the tip of the plunger 4 has a solidified layer peeling surface 40 provided with the blade 41. Therefore, as shown in FIG. 3B, the solidified layer 80 is pressed from the center of the bottom so as to be separated left and right by the blade 41. Then, as the plunger 4 advances, the solidified layer 80 is sequentially dispersed in the left-right direction at the distal end. Thus, the solidified layer 80 is sequentially peeled off as the plunger 4 advances.

On the other hand, as shown in FIGS. 3B and 3C, the solidified layer 80 apart from the tip of the plunger 4 maintains the half cylindrical shape in contact with the sleeve 3. for that reason,
The molten metal 8 in the sleeve located on the side closer to the cavity 2 is maintained in a sound state that hardly contains the broken solidified layer 80.

That is, the molten metal 8 in the sleeve 3 at the time of the above-mentioned pressurization is placed on the tip side of the plunger 4.
The peeled solidified layer 80 is successively mixed in with the advance of the substrate, but the opposite side close to the cavity 2 can be maintained in a state where the separated solidified layer 80 is hardly mixed. Therefore, the molten metal 8 sent into the cavity 2 with the advance of the plunger 4 is sent in a sound state that hardly contains the solidified layer.

The solidified layer 80 peeled off from the sleeve 3 partially reaches the runner after the pressurization is completed.
Most of it remains in the surplus molten metal remaining in the sleeve 3. Therefore, the casting obtained in the cavity is excellent in quality and hardly contains a fractured chill layer. Further, it is possible to avoid deterioration of the run-off property during casting.

COMPARATIVE EXAMPLE 1 As shown in FIG. 4, in this comparative example, in order to further clarify the effects of the first embodiment, the plunger 94 having no flattened surface 940 without the solidified layer peeling surface 40 is provided. The process of crushing of the solidified layer 80 in the case of using was investigated. This is shown in FIG.

As can be seen from FIGS. 7B and 7C, since the pressing direction to the solidified layer 80 is the same as the forward direction of the plunger 94, the solidified layer 80 is pressed in the axial direction, and Pulverized from a weak part (for example, the center). Therefore, the molten metal 8 close to the cavity 2 in the sleeve 3
In this case, the solidified layer 80 is mixed. Therefore, the crushed solidified layer 80 is easily mixed into the cavity 2 through the runner to form a broken chill layer.

On the other hand, in the case of the first embodiment, as described above, the solidified layer 80 is sequentially and smoothly dispersed at the distal end thereof as the plunger 4 advances. As a result, the above-described conventional problems can be sufficiently avoided.

Embodiment 2 As shown in FIG. 6, this embodiment is an example in which the shape of the solidified layer separation surface 40 of the plunger 4 in Embodiment 1 is changed. That is, as shown in FIG. 6, the solidified layer peeling surface 40 of the present example is provided with a blade 42 near the lower end of the tip of the plunger 4.
On the other hand, the vicinity 43 of the upper end was left flat.

In this case, the blade 42 is used in the first embodiment.
In this case, the same function and effect as those of the blade 41 are exhibited, and a cast product having excellent quality can be easily obtained. Otherwise, the same operation and effect as those of the first embodiment can be obtained.

Third Embodiment As shown in FIG. 7, this embodiment is another example in which the shape of the solidified layer peeling surface 40 of the plunger 4 in the first embodiment is changed. That is, as shown in FIG. 7, the solidified layer peeling surface 40 of the present example has a shape in which the tip of a cylinder is cut out in an arc shape from the side surface. As shown in FIG.
When the front end is viewed from the side, the upper end 431 and the lower end 432 protrude, and the center is concave in an arc. Note that the upper end 431 and the lower end 432 are finished at a slightly reduced angle to prevent abrasion.

In this case, the cross section of the lower end portion 432 for scooping the solidified layer 80 has a sharp rake face. Therefore, by moving the plunger 4 forward,
With this rake face, the solidified layer 80 is sequentially scooped upward. Therefore, as in the conventional case, the solidified layer 80
Can be sufficiently suppressed. Otherwise, the same operation and effect as those of the first embodiment can be obtained.

Further, in the horizontal pressure casting represented by the die casting shown in FIG. 1, in any of the embodiments, it is not only possible to prevent the fractured chill layer due to the incorporation of the solidified layer, but not only. Thus, the secondary effect that the entrapment of gas remaining in the space in the sleeve can be reduced regardless of whether the plunger speed is high or low is obtained.

That is, when the pressure surface of the plunger is flat, if the moving speed of the plunger is high, the molten metal undulates away from the sleeve, so that the molten metal is discharged out of the mold through a runner and a cavity prior to injection of the molten metal. Since the gas in the sleeve to be formed is drawn into the molten metal and filled in the cavity, there is also a problem that a gas defect occurs and the quality of the casting is deteriorated.

On the other hand, when the plunger of the present invention is used, since the sleeve undulates from the plunger side so as to be filled with the molten metal, the gas in the sleeve is discharged out of the mold through the runner and the cavity before the molten metal. Therefore, the occurrence of defects due to gas entrainment is reduced, and casting quality can be improved.

In each of the above embodiments, the die casting of an aluminum alloy is described. However, the material may be changed to magnesium, copper, zinc, or an alloy thereof, or the die casting may be performed by another casting method, for example, vertical casting. It is also possible to change to a high-pressure casting of a mold or the like.

In the vertical type high-pressure casting, the molten metal is poured into a sleeve provided below and then injected into a die cavity provided above. At this time, the molten metal in contact with the sleeve solidifies by injection to form a cylindrical solidified layer. In such a case, as shown in FIGS. 8A to 8C, a mountain-shaped blade 45 or a solidified layer peeling surface having a plurality of rake faces having an acute angle in cross section over the entire circumference of the pressing face of the plunger 4. By providing 40, the molten metal can be pressurized while the cylindrical solidified layer is sequentially deformed / crushed and peeled off from the plunger side.

Embodiment 4 As shown in FIG. 9, this embodiment employs a plunger 4 in a sleeve 3 in a die press casting apparatus 1 in Embodiment 1.
This is an example in which a shutter 5 is provided to prevent contact between the plunger 4 and the injected molten metal 8 before the start of forward movement. Further, the shape of the solidified layer peeling surface 40 at the tip of the plunger 4 was also changed.

As shown in FIG. 9, the shutter 5 is provided near the plunger of the molten metal injection port 35 of the sleeve 4. The shutter 5 of this example is a disk-shaped member that moves up and down, and the contact surface 50 of the molten metal or the like is provided in a planar shape. Also,
As shown in the figure, the solidified layer peeling surface 40 of this example was provided so as to have a taper that gradually protruded forward from the upper end to the lower end. Others are the same as the first embodiment.

In the present embodiment, as described above, by providing the shutter 5 on the sleeve 3, the shutter 5 can be closed to separate the plunger 4 from the molten metal 8 when the molten metal is injected. Therefore, the solidified layer peeling surface 40 of the plunger 4 can be maintained in a healthy state until the shutter 5 is opened.

After the injection of the molten metal 8 is completed,
The shutter 5 is opened just before the plunger 4 is advanced.
As a result, the contact time between the plunger 4 and the molten metal 8 that moves forward is significantly shorter than when the shutter 5 is not provided, and the thickness of the solidified metal layer formed on the solidified layer separation surface 40 is also reduced. Therefore, the peeling effect by the solidified layer peeling surface 40 can be sufficiently exhibited, and the solidification layer can be sufficiently prevented from being mixed into the cavity.

In addition, since the amount of the solidified layer adhering to the plunger 4 is reduced and the peeling effect can be sufficiently exhibited, the length of the so-called runner can be designed to be short, and the casting yield can be improved. be able to. Further, in this example, the surface of the shutter 5 that is in contact with the molten metal 8 is planar. Therefore, the formed solidified layer becomes perpendicular to the sleeve 3. Therefore, when the solidified layer is separated by the solidified layer separation surface of the plunger after the shutter 5 is opened, the separation effect can be more effectively exerted. Otherwise, the same operation and effect as those of the first embodiment can be obtained.

[0056]

As described above, according to the present invention, there is provided a mold pressure casting method and an apparatus therefor which can prevent the solidified layer of the molten metal generated in the sleeve from entering the cavity. be able to.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a configuration of a mold pressure casting apparatus according to a first embodiment.

FIG. 2A is a front view, FIG. 2B is a side view, and FIG.
FIG.

FIG. 3 is an explanatory diagram showing a peeled state of a solidified layer according to a time series ((a) to (e)) in the first embodiment.

FIG. 4 is a perspective view of a tip end portion of a plunger of the die pressure casting apparatus in Comparative Example 1.

FIG. 5 is an explanatory view showing a peeled state of a solidified layer in a time series ((a) to (e)) in Comparative Example 1.

6A is a front view, FIG. 6B is a side view, and FIG. 6C is a cross-sectional view of a plunger of a mold pressure casting apparatus according to a second embodiment.
FIG.

FIG. 7A is a front view, FIG. 7B is a side view, and FIG.
FIG.

8 (a) is a front view, FIG. 8 (b) is a side view, and FIG.
(C) Sectional view taken along line DD.

FIG. 9 is an explanatory diagram showing a shutter arrangement portion in a fourth embodiment.

FIG. 10 is an explanatory view showing a configuration of a mold pressure casting apparatus in a conventional example.

[Explanation of symbols]

 1. . . 9. Mold pressure casting equipment, . . Mold, 2. . . Cavity, 3. . . Sleeve, 4. . . Plunger, 40. . . 4. solidified layer release surface; . . 7. shutter . . Molten metal, 80. . . Solidification layer,

Claims (6)

[Claims] In a mold press casting method, a molten metal is injected into a sleeve communicating with a cavity of a mold, and the molten metal is pressed by a plunger and fed into the cavity. A mold for pressurizing the molten metal while sequentially peeling off a solidified layer generated when the molten metal is poured into the sleeve with the tip of the plunger as the plunger advances. Pressure casting. 2. The mold press according to claim 1, wherein a solidified layer peeling surface is provided at a tip of the plunger for sequentially peeling the solidified layer as the plunger advances. Casting method. 3. A mold pressure casting comprising a mold having a cavity, a sleeve communicating with the cavity, and a plunger disposed in the sleeve so as to be able to advance and retreat, and for pressurizing the injected molten metal. In the apparatus, a tip of the plunger is provided with a solidified layer peeling surface for sequentially stripping a solidified layer generated when the molten metal is poured into the sleeve as the plunger advances. Mold pressure casting equipment. 4. The apparatus according to claim 3, wherein the solidified layer separation surface of the plunger has a blade for separating the solidified layer from side to side. 5. The die pressure casting apparatus according to claim 3, wherein the solidified layer peeling surface of the plunger has a sharp rake face in cross section for scooping the solidified layer. . 6. The method according to claim 3, wherein:
A die pressure casting apparatus, characterized in that the sleeve is provided with a shutter for preventing the plunger from coming into contact with the injected molten metal before the plunger starts to advance.