JP3417988B2 - Molten forging equipment - Google Patents

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 carried out using a method and an apparatus as described in Japanese Patent Publication No. 3-4297, Japanese Patent Publication No. 3-25264, and Japanese Patent Application No. 5-296293. In other words, in these cases, the inner diameter of the injection sleeve that is bonded to the fixed mold from the lower side of the fixed mold is placed in the mold cavity formed between the lower fixed mold and the upper movable mold. After the molten metal is cast into the mold cavity through the small-diameter melt passage, it is slidably attached to the movable mold and is smaller than the diameter of the small-diameter melt passage in the fixed mold. The small-diameter pin was immediately advanced to insert the tip of the pin into the small-diameter melt passage.

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 disclosed in Japanese Patent Publication No. 3-4297 and Japanese Patent Publication No. 3-25264, the axis of the movable mold is immediately after the molten metal is filled in the mold cavity. Since only the feeder pin provided at the core is moved forward,
Although the effect of pushing is obtained to some extent, only the small area in the center of the cast product that has already hardened is pushed, so that the entire molten metal in the mold cavity is replenished. However, the feeding power was not sufficiently transmitted. Further, when the feeder force due to the action of the center pin for the feeder is transmitted to the molten metal in the mold cavity, the pressure acts to push down the injection plunger, reducing the effect of the feeder.

For these reasons as well, sufficient riser is not always performed, and a sufficiently satisfactory and dense product is not always obtained. Further, during the time when the center pin replenishes the molten metal with respect to the solidification shrinkage of the molten metal, the injection plunger continues to pressurize and cannot move to the next operation, resulting in a long casting cycle time. In addition, air remained in the mold, causing defects.

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, in order to solve these problems, the present inventor has proposed a fixed mold, a movable mold in which a plurality of cylinders are built in a movable plate, and a movable mold attached to the movable plate. Using a molten metal forging device equipped with a centering pin and a sliding stem that is slidably installed inside and has its tip facing the cavity, hydraulic pressure is applied to the rod side chamber of each cylinder. With the insert stem and center rod retracted relative to the movable mold, the movable mold and insert stem are simultaneously advanced to perform the mold clamping operation, and the molten metal is poured into the cavity by the casting operation. While filling,
By increasing the hydraulic pressure in the head side chamber of the center pin cylinder while continuing the mold clamping operation, the center pin is moved forward and closed to the mold gate while maintaining the mold clamping force, and the inside of the mold cavity is closed. In the state that the leakage of molten metal is prevented, the nesting stem is advanced to increase the pressing force acting on the molten metal in the cavity, enhance the forging effect, and further retract the injection plunger early to shift to the next operation. Invented a molten metal forging method that shortens the casting cycle time.

As a device therefor, a fixed die attached to a fixed plate, a movable die installed with a cylinder built in the movable plate, and a crosshead connecting cylinder rods are attached. A movable stem has a nesting stem that is slidably provided inside, and has a tip end facing the cavity, and a slidable center pin inside the movable die and the nesting stem. Equipped with a hydraulic device capable of increasing the hydraulic pressure acting on the head side chamber of each cylinder after the pouring operation is completed, the internal gas is exhausted in a vacuum from the gap provided in the nest stem, and the nest stem slides.
The inventor has devised a molten metal forging device that scrapes off burrs that have entered and adhered to the gap to secure a gas passage.

[0009]

In such conventional molten metal forging, the portion of the molten metal for injection by the injection plunger is connected to the cavity in the mold, and if a large surface pressure is applied to the molten metal in the cavity, it will be adversely affected. Since the injection plunger retracts due to the force, the injection plunger had to be loaded until the pressure cooling of the cavity was completed, and the casting time was long.

Further, in a typical aluminum wheel for passenger cars, the hub portion has a protrusion, and gas is apt to accumulate in this portion and defects due to bubbles are liable to be formed. In addition, a gap is provided for discharging the gas in a vacuum. It was desired to maintain the gas passage by sucking in the molten metal of aluminum and blocking the passage, dropping the burr and maintaining the gas passage.

[0011]

To this end, according to the present invention, a fixed die attached to a fixed plate, a movable die attached to a movable plate, and a cylinder incorporated in the movable plate. And a crosshead attached to the crosshead, which is slidably provided inside the movable mold attached to the crosshead, and is arranged around the center pin described later, and the tip end faces the cavity. A tubular nesting stem, a center pin slidably provided inside the nesting stem, the tip of which can be projected from the tip of the nesting stem, and a built-in movable plate. Equipped with a hydraulic device that can increase the hydraulic pressure acting on the chamber on the head side of the cylinder after the casting operation is completed, and the gas in the cavity is discharged to the outside from the gap formed around the insert stem by vacuum suction. That was squeeze casting apparatus provided with a vacuum suction device.

In addition to this structure, the tip of the center pin, which is slidably provided on the internal shaft center of the insert stem, is provided on the fixed mold immediately after the molten metal is poured into the cavity. A first drive device capable of projecting up to the gate part for molten metal casting to close the gate part, and the injection plunger can be retracted between the time when the gate part is closed and the end of the molten metal forging by the advance of the insertion stem. The molten metal forging device was provided with the second drive device.

[0013]

[Operation] First, the movable platen is moved forward by moving the movable platen in a state where the hydraulic pressure is applied to the rod side chamber of the cylinder with the movable platen and the telescopic stem is retracted relative to the movable mold. The mold and the insert stem are advanced at the same time 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 cavity is filled with the molten metal by the injection operation, and the hydraulic pressure in the head side chamber of the cylinder of the center pin is increased while the mold clamping operation is continued. Then, the center pin moves forward, and its tip closes the gate of the mold. After that, when the hydraulic pressure in the head side chamber of the cylinder for the nest stem is increased, the piston rod in the cylinder begins to move forward, and the force is transmitted to the nest stem through the crosshead, and the nest stem moves forward. As a result, the pressing force that acts on the molten metal in the mold cavity increases, and the molten metal is pressed by the area of the tip of the insert stem, and molten metal forging is performed. In this case, the surface pressure due to the nesting stem is large, and a product corresponding to it is very precise.

Since the gate is closed by the center pin during this pressing operation, no reaction force is applied to the injection plunger. Therefore, the injection plunger is retracted at a time earlier than the time when the molten metal in the cavity is solidified, and the next operation is started. However, the molten metal does not flow backward and the casting cycle time can be shortened.

Further, since the gas is discharged in a vacuum from the gap around the insert stem during the filling of the molten metal, defects due to the gas are eliminated. However, when the molten metal is filled and pressurized by the nesting stem, the reaction force causes the molten metal to enter the gap, cool and solidify, and remain as burrs even when the product is taken out. The burr is removed and the passages are kept gas flowing.

[0017]

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 manufacturing automobile wheels made of 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, 3a is a gate hole, and 4 is a cylinder provided above. A platen, 5 is a mold clamping cylinder for mold clamping, 6 is a piston rod, 7 is a movable platen that moves vertically, and 8 is a fixed platen 1.
And the cylinder platen 4 are connected to each other. 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 downward facing cylinders 9 are incorporated in the vicinity of the outer periphery of the movable platen 7, and one crosshead 11 is attached to the lower end of each piston rod 10 of the cylinder 9. On the inner center lower end side of 11,
A telescopic stem 13 having a cylindrical shape or a shape close to the cylindrical shape is attached. The back plate 7a of the movable mold 12 is provided at the lower center of the movable plate 7.
And the movable die 12, and the cylindrical insert stem 13 is provided in the through hole 12a in the movable die 12 so as to be slidable in the vertical direction, and the tip portion of the cylindrical stem 13 faces the die cavity 14. is doing.

Further, there is a small gap 41, for example, of about 0.1 to 0.3 mm, for passing gas in the lower part of the through hole 12a, and a seal 42 for preventing air from entering in the upper part.
And is connected to the atmosphere or the vacuum tank 45 by the passage 43 and the electromagnetic switching valve 44. 46 is a vacuum pump. The gap 41 may be smaller than the relatively narrow gap for sliding the insert stem 13 in the through hole 12a.

Reference numeral 15 designates 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 lower end of the outer periphery 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 denotes a center pin for hot water supply and gate cutting, which is usually called an acurad pin. The tip end of the insert stem 13 can be moved in and out from the bottom end of the insert stem 13. When the center pin 18 projects from the insert stem 13,
It can be closed by entering into the gate hole 3a of the fixed mold 3. The rear end of the center pin 18 has a movable plate 7
Is integrally connected to a piston rod 20 of a cylinder 19 incorporated in the inside of the cylinder. Inside the center pin 18, a hole for cooling water is provided up to near the tip.
Here, a hydraulic pump 26 for driving the cylinder 19, the piston in the cylinder 19 and the piston rod 20,
The four-way switching valve 29 or the like constitutes a first drive device that can close the gate hole 3a by projecting the tip of the center pin 18 to the gate hole 3a.

Reference numeral 21 denotes a casting sleeve attached to the shaft core of the stationary platen 1, reference numeral 22 denotes a plunger tip provided in the casting sleeve 21 slidably in the vertical direction, reference numeral 23 denotes an injection plunger, and reference numeral 24 denotes It is a casting cylinder, and the lower end of the injection plunger 23 is integrally connected to the piston rod 25 of the casting cylinder 24. The casting cylinder 24 is
It may be fixed to the fixed plate 1 via a connecting member,
Normally, it is convenient to be able to vertically move and tilt together with the casting sleeve 21, the plunger tip 22, etc. by a tilting device (not shown). Note that these are known and are commonly used, for example, in Japanese Patent Publication No. 57-21414 and Japanese Patent Publication No. 58-29182. The casting cylinder 24 is the center pin 1
Since the injection plunger 23 is retracted between the time when the gate hole 3a is closed by 8 and the end of the molten metal forging by moving the insert stem 13 forward, it also constitutes the second drive device for that purpose.

26 is a hydraulic pump, 27 is a relief valve, 2
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 for pressurizing the insertion pin, 31 is a core cylinder 16 is a four-way switching valve, 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, retract the center pin 18,
With the core 15 advanced, the chamber 9b on the rod 10 side of the insert pin pressurizing cylinder 9 is filled with hydraulic oil to operate hydraulic pressure. Then, the crosshead 11 goes up, and in this state, therefore, the nest stem 13 is retracted relative to the movable mold. In this state, the mold clamping cylinder 5 is operated to move the movable platen 7 downward, whereby the movable mold 12, the insert stem 13, and the center pin 18 are 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 applied from the movable platen 7 to the movable mold 1.
2, the core 15, the fixed mold 3, the lower mold 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 as shown in FIG.
1 is docked on the fixed board 1. After performing mold clamping and pouring, the casting cylinder 24 is operated to operate the plunger tip 2
2 is raised and the molten metal is cast into the mold cavity 14.
FIG. 2 shows a state during casting, and FIG. 3 shows a state where the mold cavity 14 is filled with the molten metal. 40 is a molten metal.

During casting, the outer peripheral gap 12 of the insert stem 13
The gas is discharged in a vacuum through the passage 43 from the gap 41 in the lower part of a. The molten metal 40 is filled in the cavity 14 and also enters the gap 41, but since the gap 41 is small, it is cooled and solidified immediately and does not enter the back only at the inlet.

When the mold cavity 14 is filled with the molten metal, the center pin cylinder 19 which is also the first driving device is operated while the casting force is applied to the molten metal by the action of the casting cylinder 24. Then, the center pin 18 is advanced so that the tip of the center pin 18 enters the upper end of the gate hole 3a. By the forward movement of the center pin 18, a feeder force is applied to the molten metal 40 in the mold cavity 14. Further, the upper end of the gate hole 3a is attached to the center pin 18
Block at the tip of the.

When the gate hole 3a is closed, the four-way valve 30 is operated to feed the hydraulic oil in the chamber 9a on the head end side of the cylinder 9 to move the crosshead 11 forward, and the force is applied to the cylindrical nesting stem. 13 to apply high pressure to the portion corresponding to the lower side of the insert stem 13, for example 3 ~
A relatively large surface pressure of 4 ton / cm ² is applied, and the solidified molten metal or metal is pushed in to perform molten metal forging. As a result, a product with high mechanical strength without dense cavities can be obtained. This state is shown in FIG. In this case, the mold clamping force between the movable mold 12, which is the upper mold, and the fixed mold 3, which is the lower mold, may be insufficient, but if the timing of pressurization is adjusted, the molten metal becomes plastic. The principle of Pascal does not work, and the mold is not opened and the burr is not wiped.

On the other hand, when the center pin 18 closes the gate hole 3a, it is not necessary to pressurize the biscuit with the plunger tip 22, so that the molten metal in the cavity is solidified.
Without the completion of pressure forging, the casting cylinder 24, which is also the second drive device, is actuated to retract the casting sleeve 21 and the plunger tip 22 and shift to the next operation. As a result, the cycle time of the device can be shortened. This state is shown in FIG. The pouring sleeve 21 separated from the fixed platen 1 and the fixed mold 3 is tilted together with the pouring cylinder 24, and the upper part of the pouring sleeve 21 is moved to the side of the fixed platen 1 for the next pouring.

After the pressure forging, that is, the molten metal forging is completed and the product is cooled, a predetermined operation is performed, the center pin 18 is further projected, and the biscuit 47 remaining in the gate of the lower die 3 is cut and attached. Drop it. This state is shown in FIG. Then, after the mold is opened, a product extruding device (not shown) is operated to extrude and take out the product from the movable mold 12. When the product is extruded, the nest stem 13 is also moved forward, so that the burr that has entered the gap 41 can also be pushed down. If the burr is difficult to drop, the burr can be surely cleaned by repeating the forward and backward movements of the insertion stem 13, so that the next degassing can be surely performed.

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 it is also possible to use a horizontal clamping type. 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 wheel shown in the embodiment but also for manufacturing other products.

[0034]

As described above, according to the present invention, as shown in the claims, a fixed mold attached to a fixed plate, a movable mold attached to a movable plate, and a movable plate. The crosshead attached to the cylinder built into the and the crosshead, which is attached to the crosshead, is slidably provided inside the movable mold, and is arranged around the center pin described later, and the tip part is The cylindrical nesting stem facing the cavity, the center pin slidably provided inside the nesting stem, the tip of which can be projected from the tip of the nesting stem, and the movable body. It is equipped with a hydraulic device that can increase the hydraulic pressure acting on the head side chamber of the cylinder built into the board after the pouring operation is completed, and the gas in the cavity is vacuumed from the gap formed around the nest stem. For suction Since it is a molten metal forging device equipped with a vacuum suction device that can be discharged to the outside, after the mold is clamped and cast and the molten metal is filled in the mold cavity, immediately after the action of the insert stem, It is possible to concentrate the pressure on the necessary part and perform the pressure molten metal forging of that part, and at the same time, the gas of that part is discharged, so there are no dense cavities,
Manufacturing with high mechanical strength can be reliably and easily obtained.

Immediately after the molten metal is poured into the cavity, the tip of the center pin, which is slidably provided on the inner shaft of the insert stem, is provided in the fixed mold. Drive device capable of projecting up to the gate part for use to close the gate part, and a second drive device capable of retracting the injection plunger between the time when the gate part is closed and the end of molten metal forging by advancing the nesting stem Therefore, before the molten metal forging is completed, the casting sleeve and the plunger can be quickly moved to the next operation by the gate closure by the center pin, and as a result, the casting cycle can be shortened and the productivity can be improved.

[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.

FIG. 6 is a vertical cross-sectional view showing an operating state at the time of cutting a biscuit in one embodiment of the present invention.

[Explanation of symbols]

1 Fixed board 3 fixed mold 3a Gate hole 5 Mold clamping cylinder 7 movable plate 7a back plate 9 cylinders 9a Head-end chamber 11 crosshead 12 movable mold 13 Nesting stem 14 Mold cavity 15 cores 17 Tapering 18 Center pin 19 cylinders (first drive unit) 21 Casting sleeve 22 Plunger tip 23 Injection Plunger 24 Casting Cylinder (Second drive device) 26 pumps 28-32 4-way switching valve 39 Relief valve 40 molten metal 41 Gap 42 gas seal 43 gas passage 44 Solenoid switching valve 46 vacuum pump

Front page continuation (51) Int.Cl. ⁷ identification code FI B22D 17/22 B22D 17/22 G 27/11 27/11 (58) Fields investigated (Int.Cl. ⁷ , DB name) B22D 18/02 B22D 17/12 B22D 17/22 B22D 27/11

Claims (2)

(57) [Claims] 1. A fixed mold attached to a fixed plate,
A movable die attached to the movable plate, a crosshead attached to a cylinder built in the movable plate,
A cylindrical nesting stem that is attached to the crosshead, is slidably provided inside the movable mold, and is arranged around the center pin described later, and has a tip end facing the cavity. It acts on the center pin, which is provided slidably inside the slave stem and the tip of which can protrude from the end of the slave stem, and the head side chamber of the cylinder built in the movable plate. Molten metal forging equipped with a hydraulic device that can increase the hydraulic pressure after the pouring operation is completed, and with a vacuum suction device that can discharge the gas in the cavity to the outside from the gap formed around the insert stem by vacuum suction apparatus. 2. Immediately after the molten metal is poured into the cavity,
A first end capable of closing the gate portion by projecting the tip end portion of a center pin slidably provided on the inner shaft center portion of the insert stem to a gate portion for molten metal casting provided on a fixed mold The molten metal forging device according to claim 1, further comprising a driving device and a second driving device capable of retracting the injection plunger between when the gate is closed and before the molten metal forging is completed by advancing the insert stem.