JPH0722815B2 - Oxide mixture prevention casting method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a casting method for preventing the inclusion of oxides in a product by a vertical casting die casting machine for casting a vehicle wheel or the like. is there.

[Prior Art] Wheels for vehicles such as aluminum wheels for vehicles are manufactured by a die casting technique.

FIG. 5 is a schematic vertical sectional view showing the left half of the die and the casting device of this type of conventional die casting machine with a phase shift of 45 ° with respect to the right half, which will be described with reference to FIG. , Fixed platen 1 fixed on the machine base
Is mounted with a fixed mold 2 having a cylindrical convex portion at the center thereof, and a movable platen 3 which is supported by a mold clamping cylinder (not shown) and moves up and down has a low convex portion at the central portion. The movable mold 4 is mounted. Numeral 5 designates four cores inserted movably in the horizontal direction from a position where the circumferential direction is equally divided into four between the molds 2 and 4, and a piston rod of a cylinder 6 supported on the movable platen side. Is fixed at 7,
It is configured to move back and forth in the horizontal direction by moving the piston rod 7 forward and backward by hydraulic pressure. And both molds 2,4
And the closed core 5 form a cavity 8. A casting sleeve 9 is inserted into a sleeve hole formed in the fixed platen 1 and the fixed mold 2 from below so that the plunger 9 can be moved forward and backward by a casting cylinder (not shown). The chip 10 is fitted so as to be able to move back and forth. Reference numeral 11 is a molten metal that is poured into the casting sleeve 9 with the casting sleeve 9 removed from the sleeve hole.

The cavity 8 is formed of an annular plate-shaped disc portion corresponding portion 8a and a tubular rim portion corresponding portion 8b extending downward from the outer peripheral portion thereof as a corresponding portion of a disc foil as a molded product. Then, the inventors of the present invention tried molding by connecting the degassing device 12 to the rim-corresponding portion 8b at one lower end through the degassing groove 13. This degassing device 12
Are known, for example, in Japanese Examined Patent Publication Nos. 48-46386, 59-309 and 59-310. An exhaust valve for opening and closing a valve chamber connected to the gas vent groove 13 is provided, and the exhaust valve is open during the injection of the molten metal 11 so that the gas in the cavity 8 is discharged to the outside of the machine. When the molten metal 11 reaches the exhaust valve, the molten metal 11 is closed by 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, the exhaust valve of the degassing device 12 is opened, and then the plunger tip 10 is advanced. , The molten metal 11 is pushed up in the casting sleeve 9 and reaches the portion 8a corresponding to the disk portion.
After flowing radially through the disk portion corresponding portion 8a, the rim portion corresponding portion 8b hangs by its own weight. The gas in the cavity 8 is discharged to the atmosphere through the open exhaust valve of the degassing device 12. When the molten metal 11 reaches the exhaust valve, the exhaust valve is closed by the inertial force of the molten metal 11 and the outflow of the molten metal 11 is blocked. After the molten metal 11 is filled in this way, the mold is opened after solidification and cooling of the molten metal 11, the core 5 is opened, and the molded product is taken out.

[Problems to be Solved by the Invention] However, when the molten metal of an aluminum alloy is pushed up by a plunger in a casting sleeve to be filled in the cavity of the mold by using the apparatus described above, the oxide on the molten metal surface is used. And when foreign matter in the molten metal is also filled,
There was a problem that the tensile strength of the product decreased.

[Means for Solving the Problems] In order to solve such a problem, in the present invention, the ceiling of the casting sleeve charging hole has a smaller diameter than the inner diameter of the casting sleeve and a smaller diameter on the upper side. When casting using a die with a tapered runner, insert a downward-looking edged dish-shaped wire mesh that fits into the inner wall of the runner inlet hole from below, and insert it into this inner wall from below. It was pressed and held by the frictional force with the inner wall, and then the casting sleeve containing the molten metal was docked in the casting sleeve charging hole to perform the casting operation.

[Operation] According to the present invention, there is provided an oxide trap that has a tapered surface portion that is joined to the inner wall portion of the tapered runner inlet hole above the casting sleeve charging hole and that can be arranged transversely to the runner inlet hole. Place the collecting wire mesh on a disk-shaped moving table, insert it into the casting sleeve charging hole from below, and press it against the inner wall of the taper runner inlet hole from below to form the inner wall of the runner inlet hole. After holding by the frictional force between the portion and the taper surface portion of the wire mesh, the mold is clamped.

Next, after the upper end portion of the casting sleeve into which the molten metal is injected is mounted in the casting sleeve charging hole, the molten metal in the casting sleeve is filled into the mold cavity by advancing the plunger tip. At this time, the oxide on the surface of the molten metal and the foreign matter in the molten metal are captured and removed by the wire net immediately before entering the mold cavity, and only the cleaned molten metal is cast into the cavity. When the cast molten metal solidifies, the product is cut and separated from the biscuit when the mold is opened, but the wire mesh remains as a part of the biscuit. This wire mesh is taken out together with the oxide-containing biscuits trapped in front of the wire mesh and discarded together with the biscuits, or taken out when the biscuits are remelted and used again.

[Embodiment] FIG. 1 is a vertical sectional view showing an embodiment of an apparatus for carrying out the method of the present invention, and FIGS. 2 to 4 are vertical sectional views showing other embodiments of a wire mesh. .

An embodiment of the present invention will be described below with reference to FIGS. The same parts as those in FIG. 5 are designated by the same reference numerals as those in FIG. 5, and the description thereof will be omitted.

In the apparatus for carrying out the method of the present invention, a cylindrical fixed sleeve 18 is attached to a sleeve hole 1a of a fixed die 2 which is a lower die fixed to the machine body. A cylindrical casting sleeve 9 supported on the casting cylinder side (not shown) is fitted into the inner hole of 18 so as to be freely inserted and removed. Further, a plunger tip 10, which is the head of the plunger 7 connected to the piston rod of the casting cylinder, is fitted in the inner hole of the casting sleeve 9 so as to be able to move back and forth. At the center of the ceiling of the casting sleeve charging hole, there is provided a tapered runner 13 having a smaller diameter than the inner diameter of the casting sleeve 9 and a smaller diameter on the upper side communicating with the mold cavity. As will be described later, the taper-shaped runner 13 has a taper surface 15a before the casting sleeve 9 is attached to the lower entrance portion thereof, which can be disposed transversely to the runner entrance hole for collecting oxides. The wire net 15 can be installed by being pushed in from below.
The casting sleeve 9 and the plunger 7 of the casting device are located at the casting sleeve docking position in the casting sleeve charging hole provided in the lower portion of the fixed mold 2 and below the fixed mold 2.
Moreover, it is provided so as to be movable between the hot water supply position on the side.

Above the fixed mold 2, a movable mold 4 as an upper mold, which is formed in a convex shape with its central portion facing downward, may be aligned with the fixed mold 2 or opened. It is supported so that it can move up and down. In addition, between the outer peripheral portion of the movable mold 4 and the fixed mold, the core 5 divided into four in the circumferential direction.
Is formed so as to be able to move forward and backward in the radial direction and is interposed.

In the large-diameter portion 4a of the inner hole of the movable mold 4, an extruding plate supported by an elevating plate (not shown) on the extruding cylinder side via support pins 14.
25 are slidably fitted in the vertical direction, and a plurality of extruding pins 16 and 17 are provided on the elevating plate and the extruding plate 10 at the tips thereof, respectively, the boss portion corresponding portion 8c or the disc portion corresponding portion 8a and the rim portion. The base ends are supported so as to face the corresponding portions 8b, respectively.

A pin 23 having a base end supported by a pin protruding cylinder side (not shown) is slidably inserted into a pin hole 4b formed in the center of the movable mold 4, and the molten metal is fed into the cavity 8. In the normal time before the filling of 11 is completed, the tip end surface of the pin 23 is located at the position coinciding with the inner surface of the cavity 8. The lower end portion thereof is provided so as to be freely inserted into and removed from the small diameter portion of the runner 13. The pin 23 is formed such that the diameter of the insertion portion into the runner 13 is slightly smaller than the diameter of the small diameter portion of the runner 13. For example, when the inner diameter of the small diameter portion 8c is 40 to 60 mm,
The outer diameter of 23 is smaller than this by, for example, 1 to 5 mm. In addition, the pin 23 is provided with a cooling water passage 23a extending the axial center portion thereof to a position near the tip thereof, with its rear end side being connected to a cold water source (not shown) so as to cool the pin 23 and its surroundings. It is configured. In addition, 16 and 17 are extrusion pins.

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

First, before clamping the movable mold 4 and the fixed mold 2,
Install 15. As the wire net 15, for example, the second
The ones shown in FIGS. 3, 3 and 4 were used. That is, the wire mesh 15 has a frustoconical side surface or a shape similar to this, and further, the taper portion 15a at the peripheral end portion of the wire mesh.
Is formed so as to fit into the tapered inner wall portion 13a of the runner inlet hole, and the ratio H / D of the height H and the diameter D is
It should be in the range of 0.15 to 0.5. The larger the H / D value, the more surely it can be attached to the taper inner wall surface 13a of the runner inlet hole. Sometimes I don't. Also, for example, use a mesh of about 10-12 mesh,
As the material, it is preferable to use zinc-plated iron or stainless steel that has a melting point higher than that of the molten metal 11 and does not rust. Such a wire net 15 is placed on, for example, a disc-shaped moving base (not shown), is charged into the runner entrance hole from below, and is pressed against the inner wall portion 13a of the runner entrance hole from below to form the runner entrance hole. It is held by the frictional force between the inner wall surface 13a and the taper portion 15a of the wire mesh 15.

Next, the upper and lower molds 2 and 4 are clamped. Under such a condition, the molten metal 11 is poured 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 joining surface of the adjacent cores 5, and When the plunger tip 10 is moved forward while the exhaust valve of a degassing device (not shown) provided on the joint surface with the movable mold 4 and communicating with the upper end of the cavity 8 is opened and the vacuum suction is performed, Molten metal 11 is cast into 8 and filled. At this time, the metal net 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 net 15 is first joined to the inner wall portion 13a having the taper shape of the runner inlet hole, and remains in a state of being adhered.

Immediately before or immediately after the end of pouring, the pin 23 is lowered with the pressing force being continuously applied to the plunger tip 10 and the lower end portion thereof is thrust into the molten metal 11 in the runner 13.
Since it is removed at 23 and flows into the cavity 8, the molten metal 11 acts as a feeder 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 retracted and the movable mold 4 is raised, the product reaches the movable mold 4 and rises. At this time, on the inner peripheral surface of the small diameter portion of the runner 13, a thin-walled cylindrical solidified product is formed. The solidified material referred to as a biscuit remaining in the fixed sleeve 18 is cut from the thin-walled cylindrical portion because the solidified material is formed and remains.
After opening the mold, when the core 5 is opened and the elevating plate is lowered, the extrusion pins 16 and 17 are lowered and the product is extruded from the cavity 8.

When the aluminum ingot is melted, the surface of the molten aluminum 11 comes into contact with air to generate an oxide, but if the oxide is not removed by the wire netting 15 etc., the cavity 8 is filled with the molten aluminum 11. If so, it can be seen that the tensile strength tends to be remarkably reduced depending on the degree of mixing, but in the present invention, the wire mesh 15 fitted and fitted to the inner wall portion 13a of the taper hole at the runner entrance is installed. Since the aluminum oxide is removed by using, the molten metal 11 that has passed through the wire net 15 is clean, and the desired tensile strength can be obtained.

When the molten metal 11 cast in the cavity 8 solidifies,
When the mold is opened, the product and the biscuit are cut and separated, while the wire mesh remains as a part of the biscuit. This wire mesh can be taken out together with the oxide-containing biscuits trapped in front of the wire mesh and discarded together with the biscuits as it is, or taken out when the biscuits are remelted and used again.

The above-mentioned wire net 15 is not limited to this, and for example, a net or punching metal processed with an inorganic material such as ceramic or glass fiber can be used. Further, regarding the shape of the wire mesh 15, as shown in FIG. 3, when the wire mesh 15 is fitted to the inner wall portion 13a of the runway inlet hole, in order to further increase the frictional force on the fitting surface,
When the joining portion of the taper portion 15a of the wire net 15 and the passage portion 15b of the molten metal 11 is formed in a convex shape and the wire net 15 is attached by applying a spring force, the wire net 15 is strongly pressed against the inner wall portion 13a of the runway inlet hole. Therefore, it is possible not to drop it.

Further, as shown in FIG. 4, a wire net 15 having a shape added with a spring function shown in FIG. 3 is used.
By making the structure in which 15c is bent toward the outside, the lower end portion 15c of the wire mesh is also joined to a part of the ceiling portion 20 of the casting sleeve charging hole when it is mounted on the inner wall portion 13a of the runner inlet hole. Since they are held by the wire mesh, the contact area is increased, and the wire net 15 having a further increased frictional force can be attached.

[Effects of the Invention] As described in detail above, according to the present invention, when a wire net having the above-mentioned appropriate conditions is used, it is possible to supply an extremely clean molten metal into a mold and prevent the inclusion of oxides. It is possible to obtain a desired casting product that does not.

Further, for example, a frustoconical wire mesh mounted on the inner wall portion of the taper hole at the runner entrance is placed on a disk-shaped moving table and charged into the pouring sleeve charging hole from below. It can be pressed against the inner wall of the taper hole at the inlet from below, and can be easily held by the frictional force between the inner wall of the runner hole and the taper surface of the wire mesh, and the molten metal can be poured into the cavity without any problem during casting. Can be filled. The wire mesh can be easily taken out together with the biscuit after casting.

[Brief description of drawings]

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, 3, and 4 are other embodiments showing a side view of a wire mesh, and FIG. FIG. 6 is a vertical 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 inlet hole, 15 …… Wire mesh, 18 …… Fixed sleeve.

Claims (1)

[Claims] 1. A casting runner when casting is performed using a die having a tapered runner having a diameter smaller than the inner diameter of the casting sleeve and a smaller diameter on the upper side in the ceiling portion of the casting sleeve charging hole. An oxide collecting wire mesh having a tapered surface portion joined to the inner wall portion of the inlet hole and capable of being transversely arranged in the runner inlet hole is loaded from below and is pressed against the inner wall portion from below to form the inner wall. And a taper surface portion of the wire net are held by a frictional force, and then a casting sleeve containing molten metal is docked in a casting sleeve charging hole to perform a casting operation.