JPH09253823A - Pressure casting method of molten metal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the damage of a product without damaging to a core pin by executing a push-out movement of ejecting pins at the same time of a die opening movement. SOLUTION: Injection of molten metal into a cavity in the die is completed, and after almost completing the solidification of the molten metal, a movable die plate 5 is shifted to the direction of the arrow mark A to separate a fixed die 2 and a movable die 3. At the same time of starting the die opening, an ejecting rod 13 is driven to the direction of the arrow mark B to start to separate a cast product 30 from a movable core 12 and the core pin 16 with the ejecting pins 17. Therefore, since the die separation is executed while the biting force of the molten metal to the core pin 16 caused by the solidifying shrinkage is yet weak, even if the sequential casting is executed, cracking and deformation on a hole 31 in the product 30 are not developed. Then, the damage of the core pin 16 is not developed and further, the good product free of any flaw on the base part of the hole 31 in the product 30 can be obtd. without damaging the core pin 16 during casting.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure casting method for molten metal, and more particularly to casting molten metal using a die having an extrusion pin in a die and extruding a casting part from the die cavity by the extrusion pin. Concerning the law.

[0002]

2. Description of the Related Art Generally, when a die used for pressure casting has a core pin or a convex portion with a small draft, the core pin or the convex portion is formed at a predetermined timing from the cast product in the mold cavity. If the mold is not released, solidification shrinkage of the cast product makes it difficult for the cast product to separate from the core pins and protrusions, and the holes and recesses formed in the cast product by the core pins and protrusions may become cracked or deformed. There arises a problem that the child pin is bent or broken, and a problem that the convex portion is scratched. Particularly, this problem is likely to occur in the core pin or the convex portion formed on the movable die side. This is because the cast product in the mold cavity is released from the fixed mold side at the same time as the mold opening, but the mold release from the movable mold is performed after the mold opening is completed, so the solidification shrinkage of the cast product This is because it becomes difficult to separate from the core pin and the convex portion.

To solve this problem, Japanese Patent Laid-Open No. 63-13756.
In the casting method disclosed in Japanese Unexamined Patent Publication No. 2 (1994), the core pin is pulled out from the product in accordance with the mold opening start timing so that cracks do not occur in the holes and recesses of the cast product. this is,
After the injection of the melt is completed and the solidification is completed, the mold pin opening operation starts.In order to pull out the core pin from the cast product at the timing of the operation start, the biting force of the cast product on the core pin due to solidification shrinkage is This is because the core pin comes off before it grows.

[0004]

However, the conventional casting method has the following problems. First, the conventional casting method requires a movable block that can slide freely in order to secure a drive source (cylinder) for pulling out the core pin and a gap for pulling out the core pin from the casting product inside the mold. As a result, the mold structure becomes complicated, which in turn increases the mold processing cost.

Further, in the conventional casting method, the core pin is pulled out at the same time as the mold opening operation. However, when the cast product is extruded after the die opening is completed, not only the push pin but also the core pin which is pulled out first. Also sticks out in the direction of the cast product. Therefore, the hole of the cast product formed by the core pin formed by drawing out at the same time as the mold opening is made smaller in diameter than the core pin due to solidification shrinkage, and the core pin due to the pushing operation cannot enter the already formed hole. As a result, there arises a problem that the tip portion of the core pin is damaged or the mouth of the hole formed by the core pin is damaged.

The present invention has been made in view of the above-mentioned problems of the prior art, and at a low die processing cost, there is no damage to the core pin due to protrusion of the cast product and no damage to the cast product. An object of the present invention is to provide a pressure casting method for molten metal which enables casting with a core pin or a convex portion.

[0007]

In order to solve the above-mentioned problems, the present invention provides a mold opening operation of a mold in a pressure casting method of a molten metal in which a casting part in a mold cavity is extruded by a protruding movement of an extrusion pin. At the same time, the push-out operation of the extrusion pin was performed.

The operation of the present invention having the above structure will be described. After the injection of the molten metal is completed in the mold cavity and the solidification of the injected molten metal is almost completed, the mold opening operation is started. During this mold opening operation, the casting product attached to the movable mold side is released from the movable mold by ejecting the extrusion pin.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the pressure casting method for molten metal according to the present invention will be described in detail below with reference to the drawings. [First Embodiment of the Invention] FIG.
This will be described with reference to FIG. As shown in FIG. 1, a mold 1 used for carrying out the first embodiment is composed of a fixed mold 2 and a movable mold 3, and the fixed mold 2 and the movable mold 3 are a fixed die plate 4 of a casting machine (not shown). Each is attached to the movable die plate 5. The fixed die 2 held by the fixed die plate 4 includes a fixed main die 6 and a fixed core 7 fixed inside the fixed main die 6, and the fixed core 7 forms a part of the cavity 8. Is forming. The movable die 3 held by the movable die plate 5 includes a mounting plate 9 and a movable main die 1 mounted on the mounting plate 9 via a spacer block 10.
1 and a movable core 12 fixed to the inside of the movable main mold 11 and having a core pin 16 attached to form a hole 31 in the cast product 30. The movable core 12 is one of the cavities 8. Forming a part.

Between the mounting plate 9 and the movable main die 11, there are two extrusion plates 14 and 1 which are movable in the direction of the movable main die 11 by an extrusion rod 13 penetrating the movable die plate 5 and the attachment plate 9.
5 is provided. One end of an extruding pin 17 is held on the extruding plates 14 and 15, and the extruding pin 17 is movable.
1 and the movable core 12 to reach the cavity 8.

The fixed die plate 4 has a sleeve 2
1 is attached, and a bush 22 is attached to the fixed main mold 6 at a position corresponding to the sleeve 21. The movable main mold 11 is provided with a shunt 27 for flowing the molten metal (molten metal) 25 in the sleeve 21 and the bush 22 pushed by the movement of the tip 24 held at the tip of the plunger 23 into the runner 26 leading to the cavity 8. It is provided.

Next, the operation of the injection molding die having the above structure will be described. The mold 1 performs a so-called mold opening operation for separating the fixed mold 2 and the movable mold 3 by moving the movable die plate 5 along the diver 19 in the direction away from the fixed die plate 4. In addition, the movable core 1 of the cast product 30
For extrusion from 2, the extrusion rod 13 is fixed to the die plate 4
The extrusion plates 14 and 15 are extruded toward the fixed die plate 4 by moving in the direction of. As a result, the pushing plate 14,
The extrusion pin 17 held by 15 operates in the direction of the fixed die plate 4 to extrude the cast product 30 from the cavity 8 (movable core 12) and release it.

The process of injecting the molten metal 25 will be described. At the time of injecting the molten metal, the movable die plate 5 moves to the fixed die plate 4 side most, and the fixed main mold 6 and the movable main mold 11, the fixed core 7 and the movable core 12 are in contact with each other. The fixed core 7 and the movable core 12 form a space (cavity 8) having a desired cast product shape. Further, the tip of the core pin 16 protruding into the cavity 8 is in contact with the fixed core 7. In this state, sleeve 2
1 and the molten metal 25 supplied into the bush 22 are pushed toward the shunt 27 by the movement of the tip 24 of the plunger 23. The molten metal 25 whose flow direction is changed by the shunt 27 is pushed into the cavity 8 through the runner 26.
After that, the molten metal 25 solidifies, and the core pin 16 causes the hole 31
A cast product 30 having a desired product shape in which is formed is obtained.

Next, the casting method of this embodiment will be described in detail with reference to FIGS. The injection process is performed in the mold clamped state to fill the cavity 8 with the molten metal 25 (see FIG. 1).
reference). When the molten metal 25 has solidified to such an extent that there is no problem even if the mold is opened, as shown in FIG. 2, the movable die plate 5 is moved in the direction of the arrow A to separate the fixed die 2 and the movable die 3 from each other ( Mold opening starts). At this time, consideration is given to the design of the mold 1 so that the cast product 30 is surely attached to the movable core 12 side. At the same time when the mold opening is started, the extrusion rod 1
3 is driven in the direction of the arrow B to push the extrusion plate 14 and the extrusion plate 1.
5, the casting product 30 through the extrusion pin 17, the movable core 12,
Starting to release from the core pin 16.

At this time, the driving timing of the push rod 13 is started by a limit switch (not shown) attached to a casting machine (not shown) and turned on when the mold is closed and turned off when the mold starts to open. The push rod 13 was started to be driven by the signal that the limit switch was turned off. The speed of the movable die plate 5 in the direction of arrow A is 1
The speed of the extrusion rod 13 in the direction of the arrow B, that is, the extrusion speed of the cast product 30 from the movable core 12 is 0.
It was set to 5 m / sec.

In FIG. 3, the driving of the movable die plate 5 in the direction of arrow A is completed (the mold opening is completed), and the pushing rod 13 is moved to the arrow B.
The state in which the driving in the direction is completed (the extrusion of the cast product 30 by the extrusion pin 17 is completed) is shown. Cast product 3 in this state
0 and the metal solidified in the shape of the runner 26 are removed, and the extrusion rod 13 is returned to bring the extrusion pin 17 into the state shown in FIG. Then, move the movable die plate 5 to the fixed die plate 4
The mold is clamped by moving in the direction of, and the next injection process is started, and the above-described operation is repeated to perform casting.

The mold opening speed of the movable die plate 5 (moving speed in the direction of arrow A) and the extrusion speed of the cast product 30 (moving speed of the extrusion rod 13 in the direction of arrow B) in this embodiment are limited to this. Extruded pin 1
The set speed may be such that the cast product 30 is not pressed against the stationary core 7 by the extrusion of 7.

Further, in the present embodiment, the pushing start timing is set by the limit switch for detecting the mold clamping state, but the present invention is not limited to this, and the interval between the fixed die 2 and the movable die 3 is detected. A position sensor, a sensor for detecting the position of the movable die plate 5, a switch, or the like may be used.

According to the casting method of the present embodiment, since the cast product 30 can be released from the mold at the same time when the mold is opened, the biting force to the core pin 16 due to the solidification shrinkage of the molten metal 25 is small. Since it is released from the mold, even if 10000 shots of continuous casting are performed, the holes 31 of the cast product 30 are not cracked or deformed, and the core pin 16 is not damaged. Damage to holes and holes 3 in cast product 30
It was possible to obtain a good product without scratches at the base of the mouth. Further, an auxiliary mechanism such as a cylinder used in the present embodiment is unnecessary, and casting can be performed with an inexpensive die.

[Second Embodiment of the Invention] A second embodiment of the present invention will be described with reference to FIGS. Embodiment 2
Is the same as that of the first embodiment except that the casting product 30 having a recess is formed and the extrusion start timing of the casting product 30 by the extrusion pin 17 is different from that of the first embodiment. Hereinafter, for simplification of description, only the points different from the first embodiment will be described in detail.

As shown in FIG. 4, the movable core 12 of the mold used in this embodiment is provided with a convex portion 40 which is a part of the cavity 8. The recess 32 of the cast product 30 shown is adapted to be formed. The side surface 40a of the convex portion 40 shown in FIG. 4 has a draft of 0 °.
It is taperless. Further, a brim portion 41 is attached to the plunger 23, and a forward limit switch 42 that comes into contact with the brim portion 23 when the plunger 23 moves and is turned on / off is provided at a predetermined position.

Next, the casting method of this embodiment will be described.
FIG. 4 shows the molten metal 25 through the injection process similar to that of the first embodiment.
2 shows the state where the injection into the cavity 8 has been completed, and the casting product 30 has the concave portion 30a formed by the convex portion 40 of the movable core 12.

FIG. 5 shows a state in which the mold opening is started and the extrusion of the cast product 30 by the extrusion pin 17 is started. The mold opening operation and the extrusion operation of the cast product 30 are the same as those in the first embodiment, and the description thereof will be omitted. In addition, the protrusion of the cast product 30 in this embodiment is started by a signal from the forward limit switch 42. That is, the tip 24 attached to the plunger 23 follows the mold opening and moves in the direction of the shunt 27. What determines the limit of this movement is the brim portion 41 attached to the plunger 23.
With the forward limit switch 42 that turns ON / OFF by
When the forward limit switch 42 is turned on, the shunt 27
The movement of the tip 24 to the side is stopped. The ON signal of the forward limit switch 42 is detected, and extrusion of the cast product 30 by the extrusion pin 17 is started.

FIG. 6 shows a state in which the extrusion operation of the cast product 30 by the extrusion pin 17 is simultaneously performed while the mold is further opened from the state of FIG. For this reason,
In the present embodiment, the extrusion product 17 ejects the casting product during the die opening operation, so that the casting product 30 is released earlier than in the conventional technique in which the extrusion pin ejects the casting product after the die opening is completed.

Thereafter, after the mold opening and the extrusion of the cast product 30 are completed, the cast product 30 is taken out, the extrusion pin 17 is returned and the die is clamped, and the next casting is performed, as in the first embodiment. is there.

According to the casting method of this embodiment, since the cast product 30 can be released from the mold at the same time as the mold opening, the cast product on the convex portion 40 of the movable core 12 due to the solidification shrinkage of the molten metal 25. Since the mold release was possible while the biting force of 30 was small, the recess 30a of the cast product 30 did not crack or deform, and the recess 30a did not cause galling. Furthermore, since the extrusion start timing of the cast product 30 is performed at the ON signal of the forward limit switch 42, that is, when the tip 24 stops moving, the cast product 30 is forced from the tip 24 to the shunt 27 side when the cast product 30 is extruded. Never receive. Therefore, the cast product 30 does not fall down, and the product can be stably taken out by a take-out robot or the like.

[Third Embodiment of the Invention] A third embodiment of the present invention will be described with reference to FIGS. Embodiment 3
Is to form a cast product 30 having a hole 31 inside and a recess 33 on the outer peripheral surface.

In the mold used in this embodiment, as shown in FIG. 7, a slide 45, which abuts against the fixed main mold 6 and the fixed core 7 when the mold is clamped, is vertically attached to the movable main mold 11 and the movable core 12. It is provided slidably. At the tip of the slide 45, a slide protrusion 45a forming a part of the cavity 8 is formed.
And a hole 31 is formed in the upper side surface of the cast product 30 shown in FIG. Further, the fixed main mold 6 is provided with an inclined pin 46 that projects obliquely upward toward the slide 45. The tilt pin 46 is inserted into a slide hole 45b provided in the slide 45 at the same angle as the tilt angle of the tilt pin 46, and when the mold is clamped, the tip of the tilt pin 46 is provided in the movable main mold 11 by penetrating the slide 45. The slide 45 is moved upward in response to the movement in the mold opening direction and is moved downward in response to the movement in the mold clamping direction while reaching the nigue portion 11a. Other configurations are
It is similar to the mold used in the first and second embodiments.

Next, the casting method according to the third embodiment of the present invention will be described step by step. Note that, for simplification of description, description of steps similar to those in Embodiment 1 will be omitted. FIG.
It shows a state in which the injection of the molten metal 25 is completed through the injection process similar to that of the first embodiment in the mold clamped state. At the time of mold clamping, the cavity 8 is formed by the fixed core 7, the movable core 12, the core pin 16 inserted and fixed in the movable core 12, and the slide convex portion 45a of the slide 45, and the cavity 24 is formed in the direction of the shunt 27 of the chip 24. By moving the sleeve (not shown),
The molten metal 25 in the bush 22 is filled in the cavity 8 via the runner 26.

FIG. 8 shows that the mounting plate 9 (see FIG. 7) attached to the movable die plate (not shown) starts to move away from the fixed die plate (not shown), and the fixed main mold 6 and the movable main mold are moved. 11 shows a so-called mold opening state in which 11 starts to open. The slide 45 starts to slide upward by the inclined pin 46 projecting from the fixed main mold 6 by the operation of this mold opening, and when the mold opening is performed by a predetermined amount, the slide convex portion 45a comes off from the casting product 30, and the slide convex A recess 33 having a shape corresponding to the shape of the portion 45a is formed on the upper side surface of the cast product 30.

FIG. 9 shows a state in which the cast product 30 is pushed out while the mold opening operation is further performed from the state shown in FIG. When the slide protrusion 45a of the slide 45 is completely removed from the recess 33 of the cast product 30, the cast product 30 starts to be pushed out of the movable core 12. This extruding operation is the same as in the first embodiment, and is performed by extruding the cast product 30 with the extruding pin 17 by the operation of the extruding rod 13, the extruding plates 14 and 15 (see FIG. 7). In the extrusion start signal in this embodiment, the limit switch (not shown) for detecting the mold clamping state used in Embodiment 1 is turned off.
After that, a signal is output via an external timer (not shown), and the time setting of the external timer is performed after the limit switch is turned off after the slide protrusion 45a of the slide 45.
Is set to the time until it completely comes out of the recess 33 of the cast product 30.

Thereafter, the mold opening operation and the extrusion operation of the cast product 30 are simultaneously performed, and the mold opening and the cast product 3 are performed.
When the extrusion of 0 is completed and the cast product 30 is taken out, the extrusion pin 17 is returned and the die is clamped, and the next casting is performed.
This is the same as in the first embodiment. Further, the mold clamping operation causes the slide 45 to slide downward because the inclined pin 46 is reinserted into the slide hole 45b, and returns to the position at the time of injection of the molten metal 25 to form a part of the cavity 8.

In the present embodiment, the time when the slide 45 is pulled out of the cast product 30 is set by using the external signal from the OFF signal of the limit switch for detecting the mold clamping state, and the timing of starting the protrusion of the cast product 30 is set. However, the present invention is not limited to this, and the slide convex portion 45a of the slide 45 is the concave portion 33 of the cast product 30.
A position sensor may be used to detect the position where the slide 45 is pulled out, or a push-out may be started by setting a timer based on an electrical signal before the slide 45 is pulled out of the cast product 30.

Further, the number of slides 45 is not limited to one direction and may be provided in two or more directions, and the sliding operation of the slides 45 is not limited to the method using the inclined pin 46, and the core puller is used. You may use.

According to the casting method of the present embodiment, in addition to the effect of the first embodiment, the pulling-out state of the slide 45 from the cast product 30 is fed back to the protrusion start timing of the extrusion pin 17, Even in the mold having the slide 45, the core pin 16 due to the solidification shrinkage of the molten metal 25
It is possible to release the mold while the biting force against the mold is small, the holes 31 of the cast product 30 are not cracked or deformed, and the molten metal can be cast without breaking the core pin 16. .

[Comparative Example 1] Using the mold used in the first embodiment of the present invention, when the extrusion timing of the cast product 30 was carried out after completion of the mold opening, scoring occurred on the core pin 16 after about 200 shots. Then, the hole 31 of the cast product 30 begins to deform, and the core pin 1
6 was broken.

[Comparative Example 2] Using the mold used in Embodiment 2 of the present invention, the extrusion timing of the cast product 30 was carried out after completion of mold opening.
0 Scoring occurred on the outer periphery, and the recess 32 of the cast product 30 was scratched.

[0038]

As described above, according to the present invention, since the extrusion pin ejecting operation is performed at the same time as the die opening operation, the formed hole is not affected by the solidification shrinkage of the molten metal. Cast products with no cracks in
With a low die processing cost, it has become possible to perform casting without damaging the core pin or the movable core due to extrusion and without damaging the cast product. Further, since the pushing-out operation of the extrusion pin, that is, the releasing operation of the cast product is performed at the same time as the mold opening operation, the casting cycle time can be shortened.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a state where injection of molten metal is completed after mold clamping in a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a state in which the ejection operation of the cast product is started while the mold is opened in the first embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a state in which protrusion of a cast product according to the first embodiment of the present invention is completed.

FIG. 4 is a sectional view showing a state in which injection of molten metal is completed after mold clamping according to the second embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a state in which a protruding operation of a cast product is started while the mold is being opened in the second embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a state where protrusion of a cast product according to the second embodiment of the present invention is completed.

FIG. 7 is a sectional view showing a state in which injection of molten metal is completed after mold clamping according to the third embodiment of the present invention.

FIG. 8 is a sectional view showing a state in which a protruding operation of a cast product is started while the mold is being opened in the third embodiment of the present invention.

FIG. 9 is a cross-sectional view showing a state where a cast product is ejected while the mold is being opened in the third embodiment of the present invention.

[Explanation of symbols]

 1 Mold 6 Fixed Main Mold 7 Fixed Core 8 Cavity 11 Movable Main Mold 12 Movable Core 16 Core Pin 17 Extrusion Pin 25 Molten Metal 30 Cast Product 31 Hole 32, 33 Recess 40 Convex 45 Slide 46 Sloping Pin

Claims (1)

[Claims] 1. A molten metal pressure casting method for extruding a casting part in a die cavity by an extruding movement of an extruding pin, wherein the extruding operation of the extruding pin is performed simultaneously with the die opening operation of the die. Metal pressure casting.