JPH02247062A - Casting method for preventing mixing of oxide - Google Patents

Abstract

PURPOSE:To manufacture the desired casting product without mixing oxide by inserting and holding wire net, etc., in inner wall part of inlet hole of a runner and supplying molten metal in a die in the case of casting by using the die arranged with the specific shape of the runner in insert hole of a casting sleeve. CONSTITUTION:A dish type attaching brim of the metal net 15 is pushed to the inner wall part 13a of the inlet hole of runner from lower part and held with friction force with this inner wall part 13a. After clamping both dies 2, 4 of upper and lower parts, the molten metal 11 is poured into the casing sleeve 9, and the sleeve 9 is inserted into inner hole in a fixed sleeve 18 and joined. Successively, a plunger tip 10 is advanced under vacuum sucking condition with a gas exhausting device communicating with upper part of cavity 8 to cast the molten metal into the cavity 8. Then, the metal net 15 does not pass the oxide in the molten metal and the oxide can be removed. By this method, the molten metal passed through the metal net is clean and the desired strength of the tensile strength is obtd.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a casting method using a vertical casting die-casting machine for casting vehicle wheels, etc., with the aim of preventing the contamination of refractories into products. be.

[Prior Art] Vehicle wheels such as aluminum wheels for automobiles are manufactured by die-casting technology.

FIG. 5 is a schematic vertical sectional view showing the left half of the mold and casting device of this type of conventional die casting machine with the phase shifted by 45 inches from the right half, and this will be explained based on the same figure. Fixed platen fixed above the machine space
A fixed mold 2 having a cylindrical convex portion at the center is attached to the movable platen 3, which is supported by a mold clamping cylinder (not shown) and moves up and down, and has a low convex portion at the center. A movable mold 4 is attached. Reference numeral 5 denotes four cores inserted into the space between the two molds 2°4 so as to be movable in the horizontal direction from a position dividing the circumferential direction into four equal parts, and a piston rod of the cylinder 6 supported on the movable platen side. 7, and is configured to move horizontally by moving the piston rod 7 back and forth using hydraulic pressure. And both mold 2
, 4 and the closed core 5 form a cavity 8. A casting sleeve 9 is inserted into the sleeve hole formed in the stationary platen l and the stationary mold 2 from below so as to be freely inserted and withdrawn from below. chip 1
0 is fitted so that it can move forward and backward. 11 is a casting sleeve 9
This is the molten metal that was injected into the sleeve after it was pulled out of the sleeve hole.

The cavity 8 is formed of an annular plate-shaped portion 8a corresponding to the disk portion and a cylindrical rim portion 8b extending downward from the outer periphery thereof, as a portion corresponding to a disk foil as a molded product. Then, the inventors of the present invention attempted molding by connecting a gas venting device 12 to one lower end of the rim portion 8b via a gas venting groove 13. This degassing device 12 is disclosed in, for example, Japanese Patent Publication No. 48-46386.

This exhaust valve is known from Japanese Patent Publication No. 59-309 and Japanese Patent Publication No. 59-310, and is equipped with an exhaust valve that opens and closes a valve chamber connected to a gas vent groove 13. is open during the injection of the molten metal 11 and allows the gas in the cavity 8 to pass through so as to be discharged to the outside of the machine, and the molten metal 11 is
When the molten metal 11 reaches the exhaust valve, it is configured to close due to the inertial force of the molten metal 11.

With the above configuration, when the casting sleeve 9 supplied with the molten metal 11 is inserted into the sleeve hole of the fixed mold 2, and the exhaust valve of the gas venting device 12 is opened, the plunger tip 10 is advanced. , the molten metal 11 is in the casting sleeve 9
The molten metal 11 is pushed upward and reaches the disk portion corresponding portion 8a, and after flowing radially through the disk portion corresponding portion 8a, the molten metal 11 hangs down by its own weight through the rim portion corresponding portion 8b. The gas in the cavity 8 is exhausted to the atmosphere through the open exhaust valve of the degassing device 12. When the molten metal 11 reaches the exhaust valve, the inertia of the molten metal 11 closes the exhaust valve, blocking the outflow of the molten metal 11. After filling the molten metal 11 in this manner, the molten metal 11 is solidified.

After cooling, the mold is opened, the core 5 is opened, and the molded product is taken out.

[Problems to be Solved by the Invention] However, when using the above-described device to push up molten aluminum alloy with a plunger in a casting sleeve to fill the cavity of a mold, oxides on the surface of the molten metal And when foreign matter in the molten metal is also filled,
There were problems such as a decrease in the tensile strength of the product.

[Means for Solving the Problems] In order to solve these problems, in the present invention, the ceiling of the casting sleeve insertion hole has a diameter smaller than the inner diameter of the casting sleeve, and the upper side has a smaller diameter. When casting using a mold with a tapered runner, a downward-facing edge material such as a plate-shaped wire mesh that fits into the inner wall of the runner entrance hole is charged from below, and a downward The casting sleeve is pressed down and held by the frictional force between it and the inner wall, and then the casting sleeve containing the molten metal is docked in the casting sleeve insertion hole to perform the casting operation.

In the present invention, a plate-shaped wire mesh with a downwardly facing edge 41 that fits into the inner wall of the tapered runner entrance hole at the upper part of the casting sleeve insertion hole is placed on a disc-shaped moving table and cast. Insert the sleeve into the insertion hole from below, press it against the inner wall of the tapered runner entrance hole from below, hold it by the frictional force between it and the inner wall of the runner entrance hole, and then clamp the mold. .

Next, the upper end of the casting sleeve into which the molten metal is injected is installed in the casting sleeve insertion hole, and then the molten metal in the casting sleeve is filled into the mold cavity by advancing the plunger tip. At this time, oxides on the surface of the molten metal and foreign substances in the molten metal are captured and removed by a wire mesh just before entering the mold cavity, and only the clean molten metal is poured into the cavity. Once the cast molten metal has solidified, the product is cut and separated from the biscuit when the mold is opened, but the wire mesh remains as part of the biscuit. This wire gauze is either removed with the biscuit containing the oxides captured in front of the wire gauze and discarded together with the biscuit, or taken out and used again when the biscuit is remelted.

[Example] Fig. 1 is a longitudinal sectional view showing one embodiment of an apparatus for carrying out the method of the present invention, and Figs. 2 to 4 are longitudinal sectional views showing other embodiments of the wire mesh, respectively. .

Hereinafter, the present invention will be explained in detail using FIGS. 1 to 4. Note that the same parts as in FIG. 5 are designated by the same reference numerals as those in FIG. 5, and the explanation thereof will be omitted.

In the apparatus for carrying out the method of the present invention, a cylindrical fixed sleeve 18 is fitted into a sleeve hole 1a of a fixed mold 2, which is a lower mold fixed to the aircraft body.
A cylindrical casting sleeve 9 supported by a casting cylinder (not shown) is fitted into the inner hole of the fixed sleeve 18 so as to be freely insertable and removable. Furthermore, a plunger tip 10, which is the head of a plunger 7 connected to pistons b- and do of the casting cylinder, is fitted into the inner hole of the casting sleeve 9 so as to be able to move forward and backward. A tapered runner 13 having a smaller diameter than the inner diameter of the casting sleeve 9 and having a smaller diameter at the upper side communicating with the mold cavity is provided in the center of the ceiling of the casting sleeve insertion hole. At the lower entrance of the tapered runner 13, as will be described later, a wire mesh 15 in the shape of a downward facing edge plate can be pushed in from below and installed before the casting sleeve 9 is attached. The casting sleeve 9, plunger 7, etc. of the casting device are placed at the casting sleeve docking position in the casting sleeve insertion hole provided at the bottom of the fixed mold 2, and below the fixed mold 2. Moreover, it is provided so as to be movable between it and the hot water supply position on the side.

Above the fixed mold 2, a movable mold 4, which serves as an upper mold and whose central part is convex downward, is arranged so that the mold can be matched with the fixed mold 2 or opened. It is supported so that it can move up and down. Moreover, between the outer peripheries of the movable mold 4 and the fixed mold 2, a core 5 divided into four pieces in the circumferential direction is provided.
is formed and installed so that it can freely move forward and backward in the radial direction.

An extrusion plate 10 supported by an elevating plate on the side of an extrusion cylinder (not shown) via a support pin 14 is fitted into the large-diameter inner hole 4a of the movable mold 4 so as to be slidable in the vertical direction. The elevating plate and the extrusion plate 10 each have a plurality of extrusion bottles 16.1.
7 is supported at its proximal end with its distal end facing the homo portion equivalent portion 8C or disk portion equivalent portion 8a and rim portion equivalent portion 8b, respectively.

A pin hole 4b drilled in the center of the movable mold 4 has a pin 2 whose base end is supported on the side of a cylinder for pin protrusion (not shown).
3 is slidably inserted into the cavity 8. Normally, before filling the cavity 8 with the molten metal 11, the tip end surface of the pin 23 is in a position aligned with the inner surface of the cavity 8, and when the molten metal filling is completed. During close feeder action, the pin 23 is inserted into the cavity 8
It protrudes inward, and its lower end is provided at the insertion/extraction mark with respect to the upper semi-small diameter portion of the runner 13. And this pin 23
The diameter of the part inserted into the runner 13 is formed to be slightly smaller than the diameter of the small diameter part of the runner 13. For example, the inner diameter of the small diameter part 8C is set to 4.
When the diameter is 0 to 60 mm, the outer diameter of the pin 23 is, for example, 1 to 5 mm smaller than this. In addition, the pin 23 is provided with a cooling water passage 23a extending from its axial center to near the tip, with its rear end connected to a cold water source (not shown), so as to cool the pin 23 and its surroundings. It is configured. Note that 16 and 17 are extrusion pins.

Next, a casting method using the vertical die-clamping vertical casting die-casting machine configured as described above will be explained.

First, before clamping the movable mold 4 and the fixed mold 2, the wire mesh 15 is attached. As the wire mesh 15, for example, as shown in FIG. 2, FIG. 3, and FIG. 4, a dish-shaped piece with a downward edge material was used. That is, the wire mesh 15 has a side surface shaped like a truncated conical head or a shape similar to this, and further,
The tapered part 15a at the peripheral end of the wire mesh is formed so as to fit into the tapered inner wall part 13a of the runner entrance hole,
It is necessary that the ratio H/D of height H to diameter is in the range of 0.15 to 0.5. The value of H/D is large,
It can be reliably attached to the tapered inner wall portion 13a of the runner entrance hole, but on the other hand, if the value is small, the wire mesh may rotate and fall off even after installation, and may not function as a wire mesh. Further, for example, the mesh should be about 10 to 12 meshes, and the material should be galvanized iron or stainless steel, which has a melting point higher than the melting point of the molten metal and does not cause rust.

For example, such a wire mesh 15 is placed on a disc-shaped moving table (not shown) and inserted into the runner entrance hole from below, and is pressed against the inner wall 13a of the runner entrance hole from below to close the runner entrance hole. It is held by the frictional force with the inner wall surface 13a.

Next, both the upper and lower molds 2 and 4 are clamped. Under these conditions, the molten metal 11 is injected into the casting sleeve 9, and the casting sleeve 9 is inserted into the inner hole of the fixed sleeve 18 and joined.
For example, at the joint surfaces of adjacent cores 5, and at the movable mold 4
When the plunger tip 10 is moved forward with the exhaust valve of a gas venting device (not shown), which is provided at the joint surface of the cavity 8 and communicated with the upper end of the cavity 8, with vacuum suction being applied, the molten metal 11 flows into the cavity 8. is cast and filled. At this time, the wire mesh 15 allows the molten metal 11 to pass through, but does not allow the oxide to pass through and can be captured and removed. Further, the wire mesh 15 remains in the state in which it is initially fitted and attached to the tapered inner wall portion 13a of the runner entrance hole.

Immediately before or after the end of casting, while continuing to apply a pressing force to the plunger tip 10, the pin 23 is lowered and its lower end is plunged into the molten metal 11 in the runner 13. Since the molten metal 11 is removed and flows into the cavity 8, the molten metal 11 acts as a riser and spreads to every corner of the cavity 8. After the molten metal 11 in the cavity 8 solidifies and becomes a product, when the pin 23 is moved back and the movable mold 4 is raised, the product reaches the movable mold 4 and rises. A thin cylindrical solidified material is formed and remains on the inner peripheral surface of the small diameter portion of the fixing sleeve 18.
The solidified material, called biscuit, remaining inside is cut from this thin-walled cylindrical portion.

After opening the mold, when the core 5 is opened and the elevating plate is lowered, the ejector pins 16 and 17 are lowered and the product is ejected from the cavity 8.

When an aluminum ingot is melted, the surface of the molten aluminum 11 comes into contact with air and generates oxides, but if this oxide is not removed with a wire mesh 15 etc., it will be filled into the cavity 8 together with the molten aluminum 11. However, in the present invention, the wire mesh 1 fitted into the inner wall 13a of the tapered hole at the entrance of the runner
5 to remove aluminum oxide, the molten metal 11 that has passed through the wire mesh 15 is clean and has the desired tensile strength.

When the molten metal 11 cast into the cavity 8 solidifies, the product and the biscuit are cut and separated when the mold is opened, but at this time the wire mesh remains as part of the biscuit. This wire mesh can be taken out together with the biscuit containing the oxides captured in front of the wire mesh and discarded together with the biscuit, or it can be taken out and used again when the biscuit is remelted.

The wire mesh 15 described above is not limited to this, and for example, it is also possible to use a mesh processed from an inorganic material such as ceramic or glass fiber, or a punched metal. Regarding the shape of the wire mesh 15, the third
As shown in the figure, a wire mesh 15 is attached to the inner wall 13a of the runner entrance hole.
In order to strengthen the frictional force on the mating surfaces when they are fitted, the joint between the tapered part 15a of the wire mesh 15 and the passage part 15b of the molten metal 11 is made into a convex shape, and a spring force is applied to the wire mesh 15 itself. Since the wire mesh 15 is pressed more strongly against the inner wall portion 13a of the runner entrance hole when the wire mesh 15 is attached, it is possible to prevent the wire mesh 15 from falling off.

Furthermore, as shown in FIG. 4, the wire mesh 15 having the spring function shown in FIG. When fitted to the inner wall 13a of the hole, the lower end 15c of the wire mesh is also attached to a part of the ceiling 20 of the casting sleeve insertion hole, increasing the contact area and further increasing the frictional force. The wire mesh 15 can be attached.

[Effects of the Invention] As detailed above, according to the present invention, by using a wire mesh having the appropriate conditions described above, extremely clean molten metal can be supplied into the mold, and oxide contamination can be prevented. Not the desired casting product can be obtained.

Furthermore, a wire gauze having a truncated cone shape that fits into the inner wall of the tapered hole at the runner entrance is placed on, for example, a disc-shaped moving platform and inserted into the casting sleeve insertion hole from below, and It can be pressed from below against the inner wall of the tapered hole at the runner entrance and easily held by the frictional force between the inner walls of the runner entrance hole, and the molten metal can be filled into the cavity without any problems during casting. Note that the wire mesh can be easily taken out together with the biscuit after casting.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of the apparatus for carrying out the method of the present invention, FIGS. 2, 3 and 4 are other embodiments showing side views of a wire mesh, and FIG. 5 1 is a longitudinal sectional view showing an example of a conventional apparatus for carrying out a method similar to the present invention. 2... Fixed mold, 4... Movable mold, 5... Core, 7... Plunger, 8... Cavity, 9...
・Casting sleeve, 10... plunger tip, 11... molten metal, 13... runner,
13a...Inner wall of runner entrance hole, 15...Wire mesh, 18...Fixing sleeve. Patent applicant: Ube Industries, Ltd.

Claims (1)

[Claims] When casting using a mold with a tapered runner on the ceiling of the casting sleeve charging hole, the diameter of which is smaller than the inner diameter of the casting sleeve and whose upper diameter is smaller, the inner wall of the runner entrance hole. A plate-shaped wire mesh, etc., is inserted from below into the inner wall, and is held by the frictional force between the inner wall and the casting sleeve, which is then filled with molten metal. A casting method that prevents oxide contamination by docking the casting sleeve into the insertion hole and performing the casting operation.