JP2002346721A - Die casting die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a die casting die which can be easily miniaturized. SOLUTION: The die casting die 21 comprises a first die 22 and a second die 23, and a bush 27 is fitted in a cylinder formed in the second die 23. In addition, a rotary valve 29 rotated by a driving device (not shown) is inserted into the inside of the bush 27 in order to adjust the flow passage area of a gate 31. A flow passage area adjusting part 30 which is projecting into the gate 31 and the projected area of which in the molten metal flow direction (the flow passage direction of the gate 31) changes by the rotation of the rotary valve 29 is provided on the upper end of the rotary valve 29.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a die for die casting used in the PF method.

[0002]

2. Description of the Related Art Generally, when a casting is made of aluminum or the like, a die casting method is used in which molten metal in a sleeve is extruded by a plunger tip provided at the tip of an injection rod and injected into a cavity.

FIG. 5 shows a die casting die used in the conventional die casting method disclosed in Japanese Patent Application Laid-Open No. 9-99354. Die casting mold 1 is composed of male mold 2 and female mold 3
And As shown in FIG. 5, when the male mold 2 and the female mold 3 are closed, a cavity 6 is formed by the concave part 4 formed in the male mold 2 and the concave part 5 formed in the female mold 3. You. A gate 7 communicates with the cavity 6, and the gate 7 communicates with the inside of the sleeve 9 via a flow path 8. In the sleeve 9, a plunger tip 11 provided at the tip of the injection rod 10 is accommodated so as to be able to stroke. The female mold 3 is provided with a gate cylinder 12. An access member 13 is housed in the gate cylinder 12 so as to be able to enter and exit the gate 7.

In the die casting method using the die casting die configured as described above, an inert gas such as nitrogen (contained in air) existing in a sleeve or a cavity does not react with the molten metal, and the molten gas does not react with the molten metal. In order to prevent deterioration of casting quality caused by remaining as bubbles in
A method called the law is adopted. That is, the PF method is a die casting method in which air in the cavity is replaced with an active gas such as oxygen and then a molten metal such as aluminum is poured into the cavity. Specifically, oxygen is sent as an active gas into the cavity 6, the air in the cavity 6 is replaced with oxygen, and the plunger tip 11 is stroked to send the molten metal in the sleeve 9 to the flow path 8. At this time, the access member 13 is made to protrude from the gate 7 and the flow area of the gate 7 is reduced, so that the gate 7
The molten metal injected into the cavity 6 from above becomes a mist and reacts with oxygen. This can prevent bubbles from remaining in the casting. When the pressure of the molten metal in the cavity 6 and the gate 7 increases and the pressure of the molten metal in the sleeve 9 becomes equal to or more than a predetermined value, the access member 13 is withdrawn from the gate 7 and the flow area of the gate 7 is reduced. And press the molten metal in the sleeve 9 to further press the cavity 6
Apply sufficient pressure to the melt inside. Thus, by removing the inert gas from the cavity 6 and applying sufficient pressure to the molten metal, it is possible to manufacture a casting without shrinkage cavities.

[0005]

However, in the structure described above, it is necessary to stroke the access member 13 in the gate cylinder 12 in order to obtain a suitable flow passage area in the gate 7. Therefore, a space for moving the access member 13 is indispensable. Therefore, the space must be provided in the mold, and it is difficult to reduce the size of the mold itself.

Accordingly, the present invention has been made to solve such a conventional problem, and an object of the present invention is to provide a die-casting die which can be easily reduced in size.

[0007]

According to a first aspect of the present invention, there is provided the present invention, wherein molten metal is injected from a gate into the cavity while the air in the cavity is replaced with an active gas. A die casting die for producing a casting, comprising a cylinder through which a gate penetrates, and a rotary valve having a flow area adjusting part for rotating in the cylinder in a circumferential direction to adjust a flow area. It is assumed that.

According to a second aspect of the present invention, there is provided a die casting mold, wherein the flow path area adjusting portion has a projection projecting into the gate and changing a projected area of the gate in the flow direction by rotation. It may be a feature.

According to a third aspect of the present invention, in the die casting die, the flow path area adjusting portion may have a taper.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

1 to 4 show a gate portion of a die casting die according to an embodiment of the present invention. The die casting die 21 includes a first die 22 and a second die 23.
An annular side surface 25 of a cylinder 24 is formed in the second mold 23. The first mold 22 has a gate 31 for communicating a sleeve (not shown) containing the molten metal and the cavity.
Is penetrating. The gate 31 has an opening on the outer surface of the first mold 22 that forms the mating surface PL between the first mold 22 and the second mold 23, and includes a concave surface 35 having a semicircular cross section in the flow path direction. A bush 27 is fitted in the cylinder 24. Further, a rotary valve 29 that is rotated by a driving device (not shown) for adjusting the flow area of the gate 31 is inserted inside the bush 27. At the upper end of the rotary valve 29, there is provided a flow path area adjusting section 30 having a convex portion which protrudes into the gate 31 and whose projected area in the flow direction of the molten metal (the flow direction of the gate 31) changes by the rotation of the rotary valve 29. Is provided. This convex part is a rotary valve 2
9 along one diameter direction. As shown in FIGS. 1 and 2, the flow path area adjusting unit 3 is arranged in the flow direction of the molten metal.
0 is the maximum flow area when the extending directions of the convex portions constituting 0 are parallel and have the least resistance. Further, when the extending direction of the convex portion forming the flow path area adjusting unit 30 has an angle θ with respect to the flow direction of the molten metal as shown in FIGS. 3 and 4, the flow path area becomes narrower by that amount. This is the minimum flow area. Note that this angle θ can be changed depending on the use conditions, and if you want to change the minimum flow area, you need to change the value of the angle θ without changing the rotary valve with a different convex shape. Becomes possible. Further, the convex portion of the flow path area adjusting section 30 has a taper such that the width perpendicular to the extending direction increases toward the lower portion. This taper makes this rotary valve 2
This can be easily done when the casting is to be withdrawn from 9. Also, the concave surface 3 is formed on the mating surface PL of the first mold 22.
Since only 5 is formed, the gate 31 can be easily formed using an existing mold.

Next, the operation of the die casting mold having the above-described structure will be described. First, oxygen is sent as an active gas into a cavity (not shown), and air in the cavity is replaced with oxygen. Then, the molten metal in a sleeve (not shown) is sent into the cavity through the gate 31. At this time, the minimum flow path area can be defined by rotating the rotary valve 29 and making the extending direction of the convex portion of the flow path area adjusting section 30 perpendicular to the flow direction of the molten metal. Thereby, the molten metal passing through the gate 31 is squeezed and becomes mist-like,
Reacts well with oxygen in the cavity. This can prevent bubbles from remaining in the casting.

Thereafter, when the pressure of the molten metal in the cavity or the gate increases, and when the pressure of the molten metal in the sleeve becomes a predetermined value or more, the rotary valve 29 is opened as shown in FIGS. Increase the channel area. Then, by pressing the molten metal in the sleeve, a sufficient pressure can be applied to the molten metal in the cavity through the gate 31 having the increased flow path area. Conventionally, the flow path area of the gate is determined by the stroke of the access member, but the flow path area can be adjusted by rotating the rotary valve 29 as described above. therefore,
Space for a stroke can be saved.

[0014]

As described above, according to the die-casting die according to the first and second aspects of the present invention, since the flow path area is adjusted by rotation, the access member which has been conventionally required is stroked. Space can be saved.

According to the die-casting die of the third aspect, in addition to the above-described effects of the die-casting die of the first or second aspect, the cast product can be easily pulled out of the rotary valve by the taper.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a gate portion of a die casting mold according to an embodiment of the present invention, showing a state in which a flow path area of the gate portion is maximum.

FIG. 2 is a plan view showing a relationship between a gate and a flow path area adjusting unit in the state of FIG. 1;

FIG. 3 is a cross-sectional view of a gate portion of the die-casting mold according to the embodiment of the present invention, showing a state where the flow area of the gate portion is minimum.

FIG. 4 is a plan view showing a relationship between a gate and a flow path area adjusting unit in the state of FIG. 3;

FIG. 5 is a cross-sectional view of a die casting mold used in a conventional die casting method.

[Explanation of symbols]

Reference numeral 21: die casting mold, 24: cylinder, 29: rotary valve, 30: flow path area adjusting unit.

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yoshiharu Yoshida 8 Kyowa-cho Chaya, Obu City, Aichi Prefecture Inside Toyota Sulzer Co., Ltd.

Claims (3)

[Claims] 1. A die casting mold for producing a casting by injecting molten metal from a gate into the cavity while replacing air in the cavity with an active gas, comprising: a cylinder having a gate penetrating therethrough; And a rotary valve having a flow path area adjusting portion that rotates in the circumferential direction to adjust the flow path area. 2. The die-casting device according to claim 1, wherein the flow path area adjusting section includes a projection projecting into the gate and changing a projected area of the gate in the flow direction by rotation. Mold. 3. The die casting die according to claim 1, wherein the flow path area adjusting portion has a taper.