JPH06285610A - Apparatus for squeezing molten metal - Google Patents

Abstract

PURPOSE:To obtain a dense pressurizing molten metal squeezed product high in mechanical strength without blow hole. CONSTITUTION:In an apparatus for squeezing the molten metal providing a fixing die 3 fitted to a fixing plate 1, a movable die 12 fitted to a movable plate 7 through a cylinder 9, an inserting stem 13 arranged in freely slindable in the inner part of the movable die fitted to the movable plate and faced to cavity 14 with the tip part thereof and a hydraulic device capable reducing the hydraulic pressure acted to a chamber at the movable plate side of the cylinder near the time of completing the casting movement, plural inserting stems 13 are arranged on the same circumference of circle around the axis at regular intervals.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for filling a mold cavity with molten metal and forging the molten metal.

[0002]

2. Description of the Related Art Conventionally, for example, when molding aluminum wheels for automobiles by a squeeze die casting method,
Molding was performed using the method and apparatus described in JP-B-3-4297 and JP-B-3-25264. That is, in these, in the mold cavity formed between the lower fixed mold and the upper movable mold,
After casting the molten metal into the mold cavity through a melt passage with a diameter smaller than the inner hole diameter of the injection sleeve that is arranged by joining the fixed mold to the fixed mold, it is slidably attached to the movable mold. And a pin having a diameter slightly smaller than the diameter of the small-diameter melt passage in the fixed mold is immediately advanced so that the tip of the pin is inserted into the small-diameter melt passage. It was molded.

On the other hand, there is known a molten metal forging method in which a molten metal is injected into a mold cavity which is not completely clamped and a movable mold is advanced when the molten metal is almost filled in the mold cavity. ing.

All of these are aimed at producing a dense product. However, in the case of the squeeze die casting method as described in Japanese Patent Publication No. 3-4297 and Japanese Patent Publication No. 3-25264, the axis of the movable die is immediately after the molten metal is filled in the die cavity. Since the feeder pin provided in the part is only moved forward, the feeder effect can be obtained to some extent, but only the small area in the center of the cast product that has already hardened is raised. As a result, the lifting force was not sufficiently transmitted to the entire molten metal in the mold cavity. Further, in order to sufficiently transmit the feeder force due to the action of the feeder pin to the molten metal in the mold cavity, it is necessary to pressurize a larger area with higher pressure. It is necessary to increase the power and size of the product accordingly, and this naturally has a limit. For this reason too, sufficient feeders are not always made, and a dense product that is always sufficiently satisfactory can be obtained. Didn't.

In the above-mentioned conventional molten metal forging method, the molten metal is cast into the mold cavity while the movable mold is temporarily stopped during the mold clamping just before the mold is completely clamped.
After that, the entire movable mold was further advanced to completely mold and perform the molten metal forging, so that the entire molten metal in the mold cavity was pushed in the mold clamping direction, and the unit pressure was It was too low to expect a feeder effect from the mold structure, and it was not always possible to obtain a product with consistent product accuracy, compactness and mechanical strength.

Therefore, the inventor of the present invention has filed Japanese Patent Application No. 4-1313.
As shown in No. 05, in order to solve these problems,
Fixed mold, movable mold attached to the movable platen via a cylinder, a nest mounted on the movable platen slidably inside the movable mold, and the tip of which is facing the cavity. A state in which a molten metal forging device equipped with a stem is used to actuate hydraulic pressure in a chamber on the movable plate side of a cylinder between the movable plate and the movable mold to retract the nest stem relative to the movable mold. Then, the movable die and the insert stem are simultaneously advanced to perform the mold clamping operation, the molten metal is filled in the cavity by the casting operation, and the mold on the movable plate side of the cylinder is continued while the mold clamping operation is continued. Molten metal forging method in which the mold clamping force is concentrated on the insert stem to move the insert stem forward by increasing the pressurizing force acting on the melt in the cavity by decreasing the hydraulic pressure in the chamber to enhance the forging effect. Invented

As a device therefor, a fixed mold attached to a fixed plate, a movable mold attached to a movable plate via a cylinder, and an inside of the movable mold attached to the movable plate. And a hydraulic device capable of reducing the hydraulic pressure acting on the chamber of the cylinder on the movable plate side near the end of the pouring operation, the sliding stem being slidably mounted on the cavity. The inventor of the molten metal forging device provided.

[0008]

[Patent Document 1] Japanese Patent Application No. 4-1
In the invention of No. 31305, since the circumference of the shaft center is pressed by one cylindrical nesting stem, the pressing area is wide and a large surface pressure is applied to the molten metal in the cavity in this part. I couldn't. For example, 2 ton
The surface pressure was about / cm ² . This was not a problem for aluminum wheels having a relatively small outer diameter, such as aluminum wheels for ordinary passenger cars.

However, in an aluminum wheel for a truck or the like, the outer diameter is relatively large, and a plurality of holes are provided in the disk portion at equal intervals on the same circumference around the axis. In many cases, the two aluminum wheels are placed back to back so that the disk portions come into contact with each other, and these are fastened with the bolts inserted through the plurality of holes. By the way, if there is this hole, that part becomes weak, and a large strength is required at the edge of the hole. Therefore, it is desired to press the edge portion of the hole with a stronger force to make it more precise when the feeder is performed.

[0010]

For this reason, in the present invention, instead of the conventional single cylindrical insert stem, a plurality of inserts arranged at equal intervals on the same circumference around the axis. The child stem was used. That is, in the present invention, a fixed die attached to a fixed plate, a movable die attached to a movable plate via a cylinder, and a movable die attached to the movable plate and sliding inside the movable die. Freely provided, and
In a molten metal forging device equipped with an insert stem whose tip portion faces a cavity and a hydraulic device capable of reducing the hydraulic pressure acting on the movable plate side chamber of the cylinder near the end of the casting operation, the insert stem Was a plurality of nesting stems arranged at equal intervals on the same circumference around the axis.

[0011]

[Operation] First, the movable platen is moved forward while the nest stem is retracted relative to the movable platen by operating hydraulic pressure in the chamber on the movable platen side of the cylinder between the movable platen and the movable platen. By doing so, the movable mold and the insert stem are simultaneously advanced to perform the mold clamping operation. In this state, the movable mold is completely pressed against the fixed mold for proper mold clamping, and the mold clamping force is transmitted from the movable plate to the fixed mold through the movable mold. next,
The injection operation fills the cavity with the molten metal, and the hydraulic pressure in the chamber on the movable plate side of the cylinder is reduced while the mold clamping operation is being continued. Then, the movable platen starts to move forward, the mold clamping force from the movable plate is transmitted to the plurality of nesting stems, and the nesting stem moves forward. As a result, the pressing force acting on the molten metal in the mold cavity is increased, and the molten metal is pressed at a position and area corresponding to the plurality of insert stems, and molten metal forging is performed. In this case, since there are a plurality of nesting stems, the total area of the plurality of nesting stems is smaller than the area of a conventional large cylindrical nesting stem.
Therefore, the surface pressure due to the nesting stem is large, and a product corresponding to it can be very precise. Even if the mold clamping force of the movable mold is reduced, the molten metal has already started to solidify at this time. Therefore, by adjusting the timing of reducing the hydraulic pressure in the chamber on the movable plate side of the cylinder, burrs are removed. Never blow

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the apparatus of the present invention, which is shown as a vertical molten metal forging apparatus for producing a truck wheel made of an aluminum alloy. In FIG. 1, 1 is a fixed platen that is also a horizontal lower platen, 2 is a lower mold holder, 3 is a fixed mold that is also a lower mold, 4 is a cylinder platen provided above, and 5 is a mold. A mold clamping cylinder for opening the mold, 6 is a piston rod, 7 is a movable platen that moves in the vertical direction, and 8 is a column that connects the fixed plate 1 and the cylinder platen 4. A gate hole 3a having a slightly larger inner diameter is provided downward at the center of the axis of the fixed mold 3.

Several downwardly facing cylinders 9 are incorporated in the vicinity of the outer periphery of the movable plate 7, and one cylindrical upper die holder 11 is attached to the lower end of each piston rod 10 of the cylinder 9. A movable mold 12, which is also a cylindrical upper mold, is attached to the inner lower end side of the upper mold holder 11. Thirteen
Is a plurality of rod-shaped nesting stems provided at equal intervals on the same circumference around the axis in the lower center of the movable plate 7. For example, six nesting stems 13 are movable metal. It is provided in the through hole 12a in the mold 12 so as to be vertically slidable, and its tip end faces the mold cavity 14.

Reference numeral 15 denotes several cores which are a part of the movable mold provided around the movable mold 12. In FIG. 1, the cores are incorporated in the outer peripheral lower end of the upper mold holder 11. The core cylinder 16 allows the product to be removed horizontally so that the product can be taken out. A tapered surface 15a is provided on the outer peripheral portion of the lower end of the core 15, and when the core 15 is closed and the mold is clamped, the tapered surface 15a is
The lower die holder 2 is adapted to be fitted with a taper surface 17a on the inner surface of a taper ring 17 provided on the outer periphery of the lower die holder 2.

Reference numeral 18 is a pin for hot water supply and gate cutting, which is usually called an acurad pin, and the pin 18 is slidably provided in the hole 12b of the axial core portion of the movable mold 12. The tip of the movable mold 12 can be moved in and out from the lower end of the movable mold 12.
When it is projected from, it can enter into the gate hole 3a of the fixed mold 3. The rear end of the pin 18 is integrally connected to the piston rod 20 of the cylinder 19 incorporated in the movable plate 7. Inside the pin 18,
There is a hole for cooling water near the tip.

Reference numeral 21 is a casting sleeve attached to the shaft center of the stationary platen 1, reference numeral 22 is a plunger tip provided in the casting sleeve 21 slidably in the vertical direction, reference numeral 23 is a plunger, and reference numeral 24 is a caster. It is a cylinder and a plunger 2
The lower end of 3 is integrally connected to the piston rod 25 of the casting cylinder 24. The casting cylinder 24 is the fixed plate 1
Although it may be fixed to the via a connecting member, normally,
It is convenient if the tilting device (not shown) can be vertically moved and tilted together with the casting sleeve 21, the plunger tip 22 and the like. These are disclosed in, for example, Japanese Patent Publication No. 57-21414 and Japanese Patent Publication No. 58-2.
It is known in Japanese Patent No. 9182 and the like and is commonly used.

26 is a hydraulic pump, 27 is a relief valve, 2
Reference numeral 8 is a four-way switching valve for the mold clamping cylinder 5, 29 is a four-way switching valve for the pin 18 for feeder and gate cutting, 30 is a four-way switching valve for the cylinder 9 between the movable plate 7 and the upper die holder 11,
31 is a four-way switching valve for the core cylinder 16, 32 is a four-way switching valve for the casting cylinder 24, 33 to 37 are relief valves,
38 is a check valve and 39 is a tank.

Next, the operation of the present invention will be described.
First, with the mold open, the pin 21 is retracted to move the core 15
In the state of being moved forward, the chamber 9 on the movable plate 7 side of the cylinder 9 provided between the movable plate 7 and the upper die holder 11, that is, the chamber 9a on the head end side is filled with hydraulic oil to operate the hydraulic pressure.
Then, the upper die holder 11 and the movable die 12 are pushed downward, and conversely, an upward force acts on the movable plate 7 and the nest stem 13. Therefore, in this state, the nest stem 1
3 is in a state of retreating relative to the movable mold. In this state, the mold clamping cylinder 5 is operated to move the movable platen 7 downward to move the movable mold 12 and the insert stem 13
And the pin 18 is simultaneously advanced downward to perform the mold clamping operation.

In the mold clamped state, the lower end tapered surface 15a of the core 15 is fitted to the tapered surface 17a of the taper ring 17, and the lower end surface of the core 15 is in contact with the fixed mold 3 and the upper surface of the lower mold holder 2. ing. As shown in FIG. 1, a mold cavity 14 is formed between the movable mold 12, the fixed mold 3 and the core 15. In this mold clamping state, the mold clamping force from the mold clamping cylinder 5 is transmitted from the movable plate 7 to the cylinder 9, the piston rod 10 and the upper mold holder 11, and the upper mold holder 11 moves the movable mold 12, the core 15 and the fixed mold. Type 3
And the lower die holder 2 and the fixed platen 1.

On the other hand, after lowering the casting sleeve 21 and separating it from the stationary platen 1, an unillustrated casting cylinder tilting device is operated to move the casting cylinder 24, the upper portion of the casting sleeve 21 and the like horizontally. Tilted or moved horizontally in the direction to cast the molten metal with a ladle in a place where it does not get in the way 2
Pour in 1 At this time, the plunger tip 22 may be lowered to the lower part of the casting sleeve 21 in advance. It is also possible to prevent air from being entrapped in the molten metal and to prevent the molten metal temperature from decreasing as much as possible. When the pouring of the molten metal into the pouring sleeve 21 is completed, the pouring cylinder 24 is returned to the vertical state, the pouring sleeve 21 and the like are raised, and the pouring sleeve 21 is fixed to the stationary platen 1 as shown in FIG. Dock it.

After performing mold clamping and pouring, the casting cylinder 24
Is operated to raise the plunger tip 22, and the molten metal is cast into the mold cavity 14. Figure 2 shows the state during casting
FIG. 3 shows a state in which the mold cavity 14 is filled with the molten metal. 40 is a molten metal. Once the mold cavity 14 is filled with the molten metal, the pin cylinder 2 is used in a state where the casting force is applied to the molten metal by the action of the casting cylinder 24.
0 is operated to move the pin 18 forward so that the tip of the pin 18 enters the upper end of the gate hole 3a. This pin 1
By the forward movement of 8, the pushing force is applied to the molten metal 40 in the mold cavity 14. At the same time as closing the upper end of the gate hole 3a with the tip of the pin 18, the mold cavity 1
4 to be cast product, gate hole 3a, fixed mold 3
Inside, the part of the molten metal that remains in the casting sleeve 21 and becomes the biscuit is cut. That is, the sprue cutting and sealing are performed at the same time. This state is shown in FIG.

When the gate hole 3a is closed, the relief valve 3
By gradually decreasing the set pressure of 5, the movable plate 7
Between the upper holder 11 and the upper holder 11 is gradually drained of the hydraulic oil in the chamber 9a on the rod end side of the cylinder 9 to increase the mold clamping force.
1, a movable die 12, a core 15 and a stepwise insertion stem 13
, And finally applying almost all of the mold clamping force to the plurality of nesting stems 13, each nesting stem 1
High pressure is applied to the portion corresponding to the lower side of 3 and, for example, 5 to 6
A relatively large surface pressure of ton / cm ² is applied, and the molten metal or metal that is being hardened is pushed in to perform molten metal forging. This state is shown in FIG.

At this time, a larger surface pressure than that of the conventional one can be obtained because, compared with the area of one conventional large-sized cylindrical nesting stem, the plurality of nesting stems 13 are provided.
This is because the total sum of the areas of is small. By pressure forging by the action of the nesting stem 13, the mold clamping force is concentrated on a portion requiring strength, and by forging that portion, a product having no dense cavities and high mechanical strength can be obtained. . In the figure, the white arrows indicate the action positions of the main forces.
It should be noted that the method of draining the hydraulic oil from the cylinder 9 is such that there is no burr between the movable mold 12, the core 15, and the fixed mold 3 due to the cooling of the molten metal and metal that are solidifying in the mold cavity. Adjust and do.

In this way, when the pressure forging, that is, the molten metal forging is finished and a predetermined time has passed and the product is cooled, the mold is opened, and then the product extruding device (not shown) is operated to move the movable mold 12 The product is extruded and taken out. On the other hand, the casting sleeve 21 is lowered to separate it from the fixed platen 1 and the fixed mold 3 and tilted together with the casting cylinder 24, and the upper part of the casting sleeve 21 is moved to the side of the fixed platen 1 for the next pouring. Prepare. If the casting sleeve 21 disappears under the fixed mold 3,
For example, by using a biscuit pushing tool as described in Japanese Patent Publication No. 3-4297, the biscuit remaining under the fixed mold 3 is projected and taken out. In this way, one cycle is completed. In addition, the protrusion of the biscuit is
It is also possible to advance the pin 18 further after the casting sleeve 21 is released before the mold is opened.

In the above-mentioned embodiment, an example of the vertical clamping vertical casting type is shown, but this is not necessarily limited to the vertical type, and a horizontal clamping type may be used. Further, in the above-mentioned embodiment, the example in which the core 15 is movably attached to the movable mold 12 side which is the upper mold is shown, but in this embodiment, the core 15 is movable to the fixed mold 3 side which is the lower mold. The core may not necessarily be used depending on the type of molten metal forging product to be manufactured. Of course, the present invention can be used not only for manufacturing the aluminum wheels for trucks shown in the embodiments, but also for manufacturing other products.

[0026]

As described above, in the present invention, as shown in the claims, a fixed mold attached to a fixed plate and a movable mold attached to a movable plate via a cylinder. And a nesting stem mounted on the movable plate, slidably provided inside the movable mold, and having a tip end facing the cavity, and a hydraulic pressure acting on the movable plate side chamber of the cylinder. In the molten metal forging device equipped with a hydraulic device that can reduce the porosity near the end of the pouring operation, since the insert stems were a plurality of insert stems arranged at equal intervals on the same circumference around the axis, Immediately after the mold is clamped and cast and the mold cavity is filled with molten metal, the pressing force of that part is immediately concentrated by the action of multiple nesting stems. Can forge. Therefore,
It is possible to reliably and easily obtain manufacturing with high mechanical strength and without dense cavities. In particular, in the present invention, since the nesting stem is provided in the form of being divided into a plurality of parts, the surface pressure due to the action of the nesting stem can be increased and the parts can be divided into a plurality of parts to act. As a result, it is possible to make the feeder action more effectively in the part where strength is particularly required.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing an operating state immediately after the start of filling in one embodiment of the present invention.

FIG. 3 is a longitudinal sectional view showing an operating state at the time of completion of filling in one embodiment of the present invention.

FIG. 4 is a vertical cross-sectional view showing an operating state at the time of cutting and sealing a sprue according to an embodiment of the present invention.

FIG. 5 is a vertical cross-sectional view showing an operating state during pressure forging in one embodiment of the present invention.

[Explanation of symbols]

 1 Fixed Plate 3 Fixed Mold 3a Gate Hole 5 Mold Clamping Cylinder 7 Movable Plate 9 Cylinder 9a Head End Side Chamber 11 Upper Mold Holder 12 Movable Mold 13 Nesting Stem 14 Mold Cavity 15 Core 17 Tapering 18 Pin 19 Cylinder 21 Casting Sleeve 22 Plunger Tip 24 Casting Cylinder 26 Pump 28-32 Four-way Switching Valve 39 Relief Valve 40 Molten Metal

Claims (1)

[Claims] 1. A fixed mold attached to a fixed plate,
A movable die attached to the movable plate via a cylinder, and a nesting stem attached to the movable plate, slidably provided inside the movable die, and having a tip end facing the cavity. And a molten metal forging device equipped with a hydraulic device capable of reducing the hydraulic pressure acting on the movable plate side chamber of the cylinder near the end of the pouring operation, with the insert stem on the same circumference around the axis, etc. Molten metal forging device with multiple nested stems arranged at intervals.