JPH02274359A - Die for forming wheel-shaped product and injection molding method - Google Patents

Abstract

PURPOSE:To naturally exhaust gas in cavity, etc., without splashing molten metal to outside from chill bent part by arranging the slit-state chill bent having meandering shape penetrated to the outside from a vertical through hole and a cooling passage for passing cooling medium to the outside of a throttling part. CONSTITUTION:At the time of pushing up the molten metal 11 in an injection sleeve 9 with a plunger tip 10a, the molten metal 11 is filled up into a corresponding part 8a to disk part in the cavity 8 and also resin toward upper end of a corresponding part 8b to rim part and filled up. Then, the gas in the cavity 8 is exhausted to the outside from the chill bent part 15 through a gas vent groove 13, annular groove 14 and the vertical through hole 17. At this time, the air is invaded from mating face of a fixed die 2, movable die 4 and core 5 and mating face between the each adjacent core 5, but this invaded air does not come into the cavity 8 and finally, this is easily exhausted to the outside through chill bent part 15.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a mold for forming a wheel-shaped product in a vertical injection molding apparatus and an injection molding method using this mold.

[Prior Art] For example, vertical die-casting machines are often used to cast aluminum automobile disc wheels because there is less entrainment of gas from the injection device when injecting molten metal. The left half of the mold and injection device of this type of die casting machine is 45 times larger than the right half.
2 is a schematic vertical sectional view shown with a phase shift. 2 This will be explained based on the same figure. A fixed platen l fixed on a machine base has a fixed mold having a cylindrical convex part in the center. A movable mold 4 having a low convex portion in the center is mounted on a movable platen 3 which is supported by a mold clamping cylinder (not shown) and moves up and down. Reference numeral 5 denotes four cores inserted into the molds 2 and 4 so as to be movable horizontally from a position dividing the circumference into four equal parts, and a piston rod of a cylinder 6 supported on the movable platen side. 6a
The piston rod 6a is fixed to and is configured to move horizontally by moving the piston rod 6a back and forth using hydraulic pressure. A cavity 8 is formed by both molds 2.4 and the closed core 5. An injection sleeve 9 is inserted into the sleeve holes formed in the fixed platen 1 and the fixed mold 2 from below so as to be freely inserted and removed, and a plunger tip lO that is moved forward and backward by an injection cylinder (not shown) is inserted into the injection sleeve 9. It is fitted so that it can move forward and backward.

The molten metal 11 is injected into the injection sleeve 9 after it has been removed from the sleeve hole.

The cavity 8 corresponds to a disc wheel as a molded product, and is formed by an annular plate-shaped portion 8a corresponding to a disk portion and a cylindrical rim portion 8b extending downward from the outer periphery thereof. 5. 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, Japanese Patent Publication No. 59-309, and Japanese Patent Publication No. 59-1989.
310, etc., and the gas vent groove 1
The exhaust valve is equipped with an exhaust valve that opens and closes a valve chamber connected to a valve chamber 3, and this exhaust valve is opened during injection of the molten metal 11 to allow gas in the cavity 8 to pass through so as to be discharged to the outside of the machine.
When the molten metal 11 reaches the exhaust valve, it is configured to close due to the inertia of the molten metal 11.

With the above configuration, when the injection 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 placed in the injection sleeve 9
The molten metal 11 is pushed upward and reaches the portion 8a corresponding to the disk portion, and this molten metal 11 flows radially through the portion 8a corresponding to the disk portion.

The portion 8b corresponding to the rim portion hangs down by its own weight. 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, and the molten metal i? ! The outflow of IT is blocked. After filling the melt in this way,
Solidification of molten metal 11.

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, in such a disc wheel molding die, as shown in FIG. After flowing, the molten metal 11 hanging down from the rim portion 8b is as follows:
Since the molten metal accumulates in sequence from the lower end of the rim portion equivalent portion 8b upward, the molten metal 1 is deposited in the rim portion equivalent portion 8b.
The inlet 15 of the gas vent groove 13 is closed with the molten metal 11 while the space 14 where the gas does not reach the space 1 remains.
The gas inside 4 may be trapped without being exhausted.

As a result, there was a problem in that the molten metal 11 solidified while still containing gas, creating cavities in the molded product and deteriorating the quality of the molded product.

Furthermore, when the gas in the cavity 8 is discharged by the gas venting device 12, the fixed mold 2, the movable mold 4, each core 5,
In addition, air was injected into the cavity 8 from the mating surfaces of adjacent cores 5.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a contact surface between the horizontal surface of the core and the mold on the outside of the end of the portion corresponding to the rim portion of the cavity for a wheel-shaped product. An annular groove is provided in each of the cores, and a longitudinal vertical hole communicating with the annular groove is provided in each contact surface between adjacent cores, and a slit-shaped chill vent portion having a meandering shape leading from the vertical hole to the outside. A cooling path for passing a cooling medium is provided outside the chill vent section.

Furthermore, using this mold, while moving the plunger forward and filling the cavity with molten metal, the gas in the cavity, gas vent groove, annular groove, and vertical hole is naturally exhausted without the molten metal jumping out from the chill vent part. I tried to let them do it.

[Operation] When the molten metal in the injection sleeve is pushed up by the plunger tip, the molten metal fills the portion of the cavity corresponding to the disk portion, and also rises and fills the portion corresponding to the rim portion. At this time, the gas in one cavity passes through the gas vent groove, the annular groove, and the vertical hole, and is discharged to the outside from the chill vent section. At this time, the mating surfaces of the fixed mold or movable mold and the core.

Although air sinks from the mating surfaces of adjacent cores, this injected air also does not enter the cavity and is eventually easily exhausted to the outside through the chill vent section.

In addition, due to the resistance of the slit-shaped chill vent part with a meandering shape provided between the vertical hole and the outside, the mating surfaces of the fixed mold and core, and the mating surfaces of adjacent cores In addition to being able to suppress the injected air as much as possible, the meandering shape of the chill vent allows gas to pass easily due to its small inertial force, but the molten metal is captured reliably due to its large inertial force and does not pass through the cooling path. It is sufficiently cooled by the cold water,
Because it is solidified, it does not leak directly to the outside.

[Example] Fig. 1 is a partially schematic longitudinal cross-sectional view of a mold for molding a wheel-shaped product and an injection device according to the present invention, and Fig. 2 is a partial schematic longitudinal sectional view of a mold for molding a wheel-shaped product and an injection device according to the present invention, and Fig. 2 is a partial schematic longitudinal sectional view of a mold for forming a wheel-shaped product and an injection device according to the present invention.
FIG. 3 is a plan view taken from II, and FIG. 3 is a vertical sectional view taken from ■--■ in FIG.

This embodiment will be explained using FIG. 1, FIG. 2, and FIG. 3.

A fixed mold 2, which is a lower mold to which the injection sleeve 9 is joined, a movable mold 4, which is an upper mold above the fixed mold 2, and a movable mold 4 which is an upper mold above the fixed mold 2. The four cores 5, which move forward and backward with the provided cylinders 6, form a thick-walled portion 8e corresponding to the hub portion and a corresponding portion 8a of the disk portion.
A cavity 8 is formed, which includes a portion 8b corresponding to the rim portion.

An annular groove 14 concentric with these is provided on the movable mold 4 side outside the upper end outer circumferential portion 8C of the portion corresponding to the rim portion of the cavity 8.
C is electrically connected via gas vent grooves 13 provided at several locations around the circumference, and furthermore, at least one annular groove 14 is provided on all mating surfaces of adjacent φ elements 5. Electrical conduction is provided through a vertical vertical through hole 17. Finally, like the vertical hole 17, it communicates with the outside atmosphere through a chill vent part 15 in the form of a vertical zigzag slit provided along the mating surface of the core 5. This chill vent part 15 consists of four cores 5 which are movably inserted in the horizontal direction from a position dividing the circumferential direction into four equal parts between the two molds 2°4.
For example, as shown in FIG. 2, adjacent cores 5a and 5b are fixed to a piston rod 6a of a cylinder 6 supported on a movable platen (not shown). The piston rod 6a is moved horizontally at an angle of 45 degrees by moving the piston rod 6a back and forth using hydraulic pressure, but the zigzag shape formed on the mating surfaces of the cores 5a and 5b.

The peaks as convex portions of one core 5a and the valleys as concave portions of the other core 5b are alternately formed in a slit shape with a certain gap, and the advance/retreat angle 45 of the core 5 is Draft angle (angle) θ less than °, e.g. 3
It has a shape of 7 to 38'.

Further, in the vicinity of the chill vent section 15, for example, a cooling path 24b having a U-shape as shown in FIG.

For example, the chill vent section 15 can be constantly cooled by passing cooling water. It also has a zigzag shape,
Moreover, since the molten metal 11 is sufficiently cooled in the cooling path 24, it is designed so that the molten metal 11 having a large inertia force does not jump out to the outside.

As described above, this slit-shaped chill vent part 15 is provided to smoothly discharge the gas in the cavity 8 by the feeder, and also to allow the fixed mold 2, the movable mold 4, and the core 5 to be cooled. mating surface and adjacent core 5
The air penetrating from the mating surfaces is minimized, and the molten metal 11 that has reached this point is cooled and blown while passing through this chill vent part with a large resistance.

That is, in this embodiment, as described above, after the molten metal 11 is pushed up inside the injection sleeve 9 by the plunger 10 and reaches the disk portion equivalent portion 8a, the molten metal 11 separates the disk portion equivalent portion 8a in the radial direction. The liquid then flows and reaches the cylindrical rim portion 8b. In this case, the lengths from the end of the disc portion equivalent portion 8a to the upper end outer peripheral portion 8C of the rim portion equivalent portion and the lower end outer peripheral portion 8d of the rim portion equivalent portion are different, and from the end of the latter disc portion equivalent portion 8a to the rim portion equivalent portion 8a, the lengths are different. Since the corresponding portion up to the lower end outer circumference 8d is shorter, the molten metal 11 is filled earlier on the lower end outer circumference BBd side. On the other hand, 5 molten metal 11.

The gas in the cavity 8 rises up the rim portion 8b and is filled, but at this time, the gas in the cavity 8 flows through the upper outer peripheral portion 8c of the rim portion, the gas vent groove 13. It passes through the annular groove 14, the vertical hole 17 and the chill vent part 15, and is naturally discharged out of the mold.

Further, between the hub portion equivalent part 8e of the cavity 8 and the insertion hole of the fixed sleeve 20, there is a small diameter upper half formed in a small diameter cylindrical shape, which is considerably smaller in diameter than the inner hole of the fixed sleeve 20 and the injection sleeve 9. portion 7a and tapered lower half portion 7b
A runner 7 as a molten material passage is formed so that the upper and lower sides communicate with each other.

Reference numeral 23 denotes a pin whose base end is supported by an upper cylinder for protruding the pin (not shown) and is movable in the vertical direction. In the normal state, before filling the cavity 8 with the molten metal 11, the tip end surface of the pin 23 is in the same position as the inner surface of the cavity 8, and when the feeder is working near the completion of filling the molten metal, The pin 23 projects into the cavity 8, and its tip is provided so that it can be inserted into and removed from the runner 7. The outer diameter of this pin 23 is formed to be slightly smaller than the diameter of the small diameter portion of the runner 7. For example, when the inner diameter of the small diameter portion 7a is 40 to 60 mm.

The outer diameter of the pin 23 is smaller than this by, for example, 1 to 5 mm. The pin 23 is also 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).
3 and its surroundings. Note that 12 and 16 are extrusion pins.

The operation of the vertical die casting machine configured as above will be explained.

When the plunger 10 is moved forward by the injection cylinder while the mold is clamped and the injection sleeve 9 into which the molten metal 11 is injected is joined to the fixed sleeve 20, the molten metal 1u is
ll is pushed by the plunger tip 10a, and the cavity 8
It is injected inside and begins to fill.

The molten metal 11 that has entered the cavity 8 through the runner 7 first fills a portion 8e of the cavity 8 corresponding to the hub portion 5.
Next, after filling the disk portion equivalent portion 8a, the rim portion equivalent portion 8b is filled. Here, the molten metal 11 accumulates sequentially from the lower end of the rim portion 8b, that is, the lower end outer periphery 8d of the rim equivalent portion, and from the end of the disk portion 8a to the lower end outer periphery 8d of the rim portion equivalent portion. A part of the gas occupying the cavity part is discharged to the outside from the mating surface of the fixed mold 2 and the core 5, but the remaining gas is discharged from the molten metal 11.
Then, the molten metal 11 is sequentially filled from the end of the disc part equivalent part 8a to the upper end outer peripheral part 8C of the rim part equivalent part, When the molten metal 11 reaches the upper end outer circumferential portion 8C of the portion corresponding to the rim portion, the filling of the molten metal 11 into the product cavity 48 is tentatively completed, but at this point, the plunger tip 10a has not reached its forward limit, so the plunger 10 advances, the molten metal 11 fills the gas vent groove 13, the annular groove 14 and the vertical hole 17 one after another, and finally flows into the mold cavity 8 from the slit-like chill vent part 15 having a zigzag shape. While the gas is discharged, the molten metal 11 is cooled and solidified while passing through the chill vent part 15, which has a large flow resistance and is cooled by the passage of cooling water into the cooling path 24, and the filling is completed.

As described above, the annular groove 14 was provided between the movable mold 4 and the core 5, and the vertical hole 17 was made to conduct therethrough.

However, the present invention is not limited to this, and an annular groove may be provided between the movable mold 4 and the core 5 and between the fixed mold 2 and the core 5, and a communication pipe may be provided that is connected to the annular groove. It is also possible to adopt a structure in which the gas in the cavity 8 is discharged from the upper and lower ends of the rim portion equivalent portion 8b.

Further, an annular groove is provided between the fixed mold 2 and the core 5, and a gas venting groove is provided which communicates with the annular groove to the lower end outer circumferential portion 8d of the portion corresponding to the rim. A vertical through hole 17 is provided to provide electrical conduction, and this vertical through hole 17
A slit-shaped chill vent portion having a zigzag shape may be provided between the outside and the outside.

When a mold having the above-mentioned configuration is used, the gas in the cavity 8 is easily discharged to the outside as the molten metal 11 is filled into the cavity 8, but the structure is simple, so failures are rare. , and a movable mold 4 and a core 5. Further, since the amount of air that sinks into the mold from between the fixed mold 2 and the core 5 is small, the gas in the cavity 8 is also easily discharged.

[Effects of the Invention] As is clear from the above description, according to the present invention, when filling the cavity with molten metal in a mold for forming a wheel product, the gas in the cavity is distributed to the mating surface of the core. Although the molten metal is easily naturally discharged from the provided slit-shaped chill vent section, the molten metal is formed into a slit-shaped passage having a zigzag shape in the chill vent section to provide flow resistance, and
Cooling channels are provided on both sides of the chill vent to cool the area around the chill vent, so molten metal with a large inertia can collide with the inner wall of the chill vent, solidify, and be captured, so it will not be scattered outside. ,Also.

Since the gas in the cavity is not forcibly sucked in and discharged using a vacuum suction device, it is trouble-free and inexpensive; As a result, the amount of gas that sinks into the cavity is small, and the gas in the cavity is easily discharged from the chill vent part.

[Brief explanation of drawings]

FIG. 1 is a partially schematic longitudinal cross-sectional view of a mold for molding a wheel-shaped product and an injection device according to the present invention, and FIG. 2 is a partial longitudinal sectional view of If -
FIG. 3 is a vertical cross-sectional view taken along the line m-■ in FIG. 2, FIGS. 3 and 4 show a conventional mold for forming a wheel-shaped product, and FIG. FIG. 5 is a partially exploded schematic longitudinal cross-sectional view of the injection device, and a perspective view of the convex portion of the fixed mold shown for explaining the flow of molten metal in the cavity. 2...Fixed mold, 4...Movable mold, 5...φ child, 7...
... Runway, 8... Cavity, 8a... Part corresponding to the disk part. 8b... Portion equivalent to the rim portion, 8c... Upper outer periphery of the portion equivalent to the rim portion, 8d... Lower end outer periphery of the portion equivalent to the rim portion. 9... Injection sleeve, 10... Plunger, 13... Gas vent groove, 14.
...Annular groove. 15... Chill vent part, 17... Vertical hole. 20... Fixed sleeve, 24...
cooling path. Patent applicant: Ube Industries, Ltd.

Claims (2)

[Claims] (1) An annular groove is provided at the contact surface between the horizontal surface of the core and the mold on the outside of the end of the portion corresponding to the rim of the cavity for wheel-shaped products. A vertical through hole communicating with the annular groove is provided, a slit-shaped chill vent portion having a meandering shape is provided extending from the vertical hole to the outside, and a cooling medium is passed outside the constricted portion. A mold for forming wheel-shaped products characterized by having a channel. (2) Using the mold according to claim 1, while moving the plunger forward to fill the cavity with molten metal, the gas in the cavity, gas vent groove, annular groove, and vertical hole is naturally exhausted from the chill vent part. An injection molding method using a mold for forming a wheel-shaped product.