JPH0157985B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method of pouring molten metal into a mold in a die-casting machine, in which the molten metal is injected into a cavity of a mold that is clamped.

[Prior art]

Traditionally, many die casting machines had the mold clamping direction and the injection direction in the same direction, but in recent years, horizontal mold clamping machines and vertical mold molding machines have been developed, which inject the molten metal from below into the cavity of a mold clamped horizontally. A casting type die casting machine has been developed.

This type of die casting machine has the advantage that the length of the molten metal in the casting sleeve before injection is short, so the temperature of the molten metal does not drop much. The injection plunger faces the cavity at the time of filling, so the pressure is effectively transmitted. There was a problem in that the molten metal solidified on the side wall surface of the casting sleeve entered the cavity due to the drop, degrading the quality of the product.

In order to prevent this, conventionally a stopper ring was provided inside the casting sleeve to prevent the solidified material from entering, but in this case the stopper ring had to be inserted and removed each time the casting was performed. However, the disadvantage was that the work was complicated and work efficiency was reduced.

Therefore, the present applicant proposed a die-casting method and apparatus disclosed in Japanese Patent Publication No. 58-55859 to prevent the intrusion of the coagulated material. This is achieved by providing a constriction and a large-diameter vertical hole extending below the constriction at the connection between the mold cavity and the casting sleeve. A thin cylindrical solidified material called a shell formed along the inner circumferential surface is injected while being compressed in a bellows shape between the plunger and the step plane in front of the constriction, so that the shell is inserted into the vertical hole. It is made to remain in the interior of the cavity to prevent it from entering the cavity.

However, in such methods and devices, when the plunger is moved far forward until it comes close to the constriction in an attempt to reduce the solidification of molten metal remaining in the vertical hole called a biscuit, the shell does not remain and enters the cavity. However, I was not able to expect satisfactory results.

[Summary of the invention]

The present invention has been made in view of the above points, and is a horizontal clamping, vertical casting type die casting machine, in which a double structure plunger consisting of an outer plunger and an inner plunger arranged concentrically is housed within a casting sleeve. Injection is performed while moving the tip forward to form a thin cylindrical solidified substance between the constriction at the bottom of the mold cavity and the plunger tip, and in the middle of injection, the small-diameter inner plunger tip is advanced to fill the vertical hole at the bottom of the mold. Casting molten metal into a mold that completely prevents solidified material from entering the cavity and improves product quality by leaving the solidified material in the space formed within the cavity and injecting only the molten metal. The present invention provides a method. Embodiments of the present invention will be described in detail below with reference to the drawings.

〔Example〕

FIG. 1 is a vertical cross-sectional view of a horizontal die-clamping, vertical casting die-casting machine shown to explain the method of pouring molten metal into a mold according to the present invention, and FIG.
The cross-sectional view, FIG. 3, is also an enlarged cross-sectional view of the part where the molten metal is poured into the mold cavity. In the figure, a die casting machine 1 is equipped with a horizontal mold clamping unit 2 and a vertical casting unit 3, and the horizontal mold clamping unit 2 includes:
A machine base 4 fixed to the floor surface, a fixed plate 5 fixed to one end of the machine base 4, and a fixed plate (not shown) fixed to the other end of the machine base 4 so as to be movably adjustable.
and is provided. Reference numeral 6 denotes a column that connects the four corners of both fixed plates and is fixed with a nut 7. A movable plate 8 is supported on this column 6 so as to be able to move forward and backward with respect to the fixed plate 5. Board 8
A toggle mechanism 9 connects the mold clamping cylinder and a mold clamping cylinder (not shown) on the stationary platen side. 1
0 is a fixed mold that is mounted on a fixed platen 5 and whose movement in the vertical direction is regulated by a key 11, and 12 is a movable mold that is mounted on a movable platen 8 and whose movement in the vertical direction is regulated by a key 13. Both of these molds 1
0 and 12 are joined so that they can be opened and closed in the horizontal direction with the dividing surface 14 as a boundary.

Both molds 10 and 12 have a cavity 15 having the same shape as the cast product, a constriction 16 continuing below the cavity 15, and a large-diameter vertical hole 17 having an opening at the bottom following the constriction 16. are provided separately by the dividing surface 14, and a shell contact surface 18, which is a plane orthogonal to the axis, is formed at the boundary between the constriction portion 16 and the vertical hole portion 17. Further, a half-shaped fixing sleeve 19 is fitted into the vertical hole 17 . 20 is a molded product cavity 15
This is a product extrusion device that extrudes products from within.

In such a horizontal mold clamping unit 2, by moving a piston rod of a mold clamping cylinder fixed to a fixed platen (not shown) back and forth, the movable platen 8 moves back and forth via a toggle mechanism 9 to clamp both molds 10 and 12. After the mold is opened and the mold is closed, the molten metal is poured into the cavity 15 by the hard casting unit 3.

The frame 21 of the vertical casting unit 3 is erected in a pit 22 provided below the mold clamp and supports the end of the machine base 4.
Inside the pit 1, a cast frame 24 connected to the lower column 6 by four support rods 23 is provided close to the bottom surface of the pit 22. Reference numeral 25 denotes an injection cylinder rotatably supported on the cast frame 24. A plunger 27 is connected to the piston rod 26 via a coupling 28, and the plunger 27 is raised and lowered by the hydraulic pressure of the injection cylinder 25. is configured to do so. 29
29 is a block supported by fitting a pair of rams 30 implanted on the upper end surface of the injection cylinder 25 into ram holes, and the hole at the lower end is engaged with the piston rod 26. The block 29 is raised and lowered by pressure oil introduced into a cylinder 31 provided in the cylinder 31 and by the lowering of the piston rod 26. A casting sleeve 32 formed in a cylindrical shape with the same center and the same diameter as the fixed sleeve 19 is fixed to the upper end of the block 29. When the block 29 is raised by the hydraulic pressure of the cylinder 31, the casting sleeve 32 and Fixed sleeve 1
When the block 29 is lowered, the sleeves 32 and 19 are separated from each other.

The plunger 27 injects the molten metal poured into the casting sleeve 32 of the vertical casting unit 3, which is tilted by a tilting device to be described later, into the cavity 15 by rising. An outer plunger tip 33 is integrally formed at the upper end and has approximately the same diameter as the inner diameter of the casting sleeve 32 and slides inside the casting sleeve 32 and a part of the fixed sleeve 19 as the plunger 27 advances and retreats. . In addition, the outer plunger tip 33 and the plunger 2
7 are both provided with an inner hole, and an inner plunger 34 is fitted into this inner hole so as to be freely advanced and retractable.
An inner plunger tip 35 formed in a cylindrical shape having a smaller diameter than the outer plunger tip 33 is integrally formed. Normally, the inner plunger tip 35 is arranged such that its upper end plane is located on the same plane as the upper end plane of the outer plunger tip 33 when it is at its retraction limit. An oil chamber 36 into which pressure oil is introduced is provided below the inner hole of the plunger 27, and the pressure oil can be fed into the oil chamber 36,
By removing pressure oil from the oil chamber 36, the inner plunger 34 moves up and down, and the inner plunger tip 35 moves in and out of the outer plunger tip 33. Note that the inner plunger tip 35 is inserted into the outer plunger tip 3 during the pouring of the molten metal by the plunger 27.
The timing is set so that it stands out from 3. As a result of the inner plunger tip 35 protruding, a cylindrical space 19a is formed between it and the inner peripheral surface of the fixed slip 19.

Reference numeral 37 is a tilting cylinder pivotally supported on the frame 21 side, and the working end of its piston rod is pivotally connected to the injection cylinder 25, and when the block 29 is lowered, both sleeves 19,
By operating the tilting cylinder 37 with the parts 32 and 32 spaced apart, the entire rigid casting unit 3 is configured to stand up and tilt between the casting position shown in the figure and the inclined pouring position. There is. Reference numeral 38 denotes an adjustable stopper that abuts the injection cylinder 25 to limit its rotation toward the casting position.

A method of pouring molten metal into a mold using the die casting machine configured as described above will be explained. When the fixed mold 10 and the movable mold 12 are respectively mounted on the fixed platen 5 and the movable platen 8, and the piston rod of the mold clamping cylinder (not shown) is advanced, the movable platen 8, which is in the mold opening position, moves to the toggle mechanism 9. The mold is moved to the illustrated mold clamping position through the mold clamping position, and mold clamping is performed. During this mold clamping, the piston rod 26 of the injection cylinder 25
has been lowered to the position shown, and block 29
is lower than the position shown in the illustration, and both sleeves 1
9 and 32 are separated, the tilting cylinder 34
When the piston rod of
It comes out from below (on the right side in Figure 1). After pouring the molten metal into the casting sleeve 32 by squeezing or the like, the tilting cylinder 34 is operated again to raise the vertical casting unit 3 vertically.
When pressure oil is introduced into the cylinder 31 of the block 29, the block 29 is raised and the casting cylinder 32 is concentrically pressed against the lower surface of the fixed sleeve 19.

After this, pressure oil is introduced into the injection cylinder 25 to raise the piston rod 26, and the plunger 27 is raised via the coupling 28, so that the mold 10,
The sleeve 32 is cast into the cavity 15 of 0 and 12.
Pour the molten metal inside. In this case, before the molten metal is poured, a part of the molten metal along the inner wall surface of the casting sleeve 32 begins to solidify, and a thin cylindrical solidified material,
A so-called shell 39 is generated. This ciel 39
is pushed up by the outer plunger tip 33 while maintaining its cylindrical state as the plunger 27 rises, and after the upper end of the shell 39 contacts the shell contact surface 18, it is compressed by the rise of the outer plunger tip 33. Ru. Therefore, when pressure oil is fed into the oil chamber 36 in the plunger 27 after the start of compression of the shell 39, the inner plunger 34 rises and the inner plunger tip 35 protrudes from the upper end surface of the outer plunger tip 33. After injecting the molten metal, the outer plunger tip 33 only acts to compress the shell 39. In this case, the molten metal flows from the part farthest from the shell 39, that is, from the high temperature part at the upper center to the constriction part 16.
The materials are sequentially fed into the cavity 15 through the. When both the plunger tips 33 and 35 have finished rising in this manner, as is clear in FIG. 19a. Therefore, even if the plunger 27 is raised to the maximum in an attempt to reduce the amount of biscuits that are extra solidified matter attached to the cast product, the shell 39 is captured in the space 19a and remains therein, causing the cavity 15 There is no intrusion inside.

When the injection is completed and the molten metal in the cavity 15 is solidified and cooled to become a product, first, pressurized oil is supplied to the upper side of the oil chamber 36 and the inner plunger tip 3
5 and retract it into the outer plunger tip. Note that if the inner plunger tip 35 and the outer plunger tip 33 are lowered at the same time, the shell 39 may break at the upper end of the inner plunger tip 35, or the shell 39 may break at the upper end of the inner plunger tip 35.
There is a risk that the entire body may stick to the inner plunger tip 35 and fall. Therefore, when lowering the plunger tip, the inner plunger tip 35 is first lowered to the same position as the outer plunger tip 33, and then both plunger tips 33, 35 are lowered simultaneously.
When the inner plunger tip 35 is lowered, the pressure oil in the cylinder 31 is released and the block 29 is lowered to separate the casting sleeve 32 from the fixed sleeve 19, and the injection cylinder 25
The pressure oil is removed and the plunger 27 is lowered. Then, by retracting the piston rod of the mold clamping cylinder, the movable platen 8 is moved away from the fixed platen 5 to open the mold, and the product extrusion device 20 extrudes the cast product, completing one cycle. finish. The products taken out from the molds 10 and 12 include a solid object, a so-called biscuit, which has the same shape as the space 19a in FIG. can do. In this method, as described above, there is no possibility that the shell 39 will enter the cavity 15, so the plunger 27 can be raised to the maximum extent, so that the thickness of the biscuit can be reduced.

In the above embodiment, when the inner plunger tip 35 is retracted, the upper end plane of the inner plunger tip 35 is located on the same plane as the upper end plane of the outer plunger tip 33. Even when the inner plunger tip 35 is retracted, the inner plunger tip 35 can always be made to protrude more than the outer plunger tip 33. In this case, the amount of protrusion of the inner plunger tip 35 at the retraction limit can be made approximately the same as the diameter of the inner plunger tip 35. By doing this, even before only the inner plunger tip 33 is raised in the latter half of casting, the shell 39 remains around the inner plunger tip 33 that protrudes as the plunger rises. It is possible to prevent the shell 39 from entering the cavity 15.

FIG. 4 is an enlarged sectional view of the part for pouring molten metal into the mold cavity shown in correspondence with FIG. 3 for explaining another embodiment of the present invention, and in this embodiment, the outer plunger tip 33 The upper half 33A is made small in diameter and subjected to a taper process of, for example, 3 to 5 degrees,
Further, the insertion hole 1 in which the inner plunger tip 35A is inserted between the constriction portion 16 and the vertical hole portion 17 is provided.
9b was installed. And outer plunger tip 3
3 is raised to the protruding position of the inner plunger tip 35 in the embodiment described above, and from this position the inner plunger tip 35 is further protruded and inserted into the insertion hole 19b. By doing this, the upper half portion 33A of the outer plunger tip 33 serves as the inner plunger tip 35, and captures the shell 39 in the space between it and the casting sleeve 19 and causes it to remain there. By applying the taper process, it is possible to improve the extraction condition when lowering the plunger, and it is easy to capture the shell 39.
Moreover, almost all of the molten metal within the fixed sleeve 19 is injected into the cavity 15 by the protrusion of the inner plunger tip 35, so the amount of biscuits is reduced and the product yield is further improved.

FIG. 5 is an enlarged cross-sectional view of a part for pouring molten metal into a mold cavity shown in correspondence with FIG. 3 to further explain another embodiment of the present invention, and in this embodiment, a vertical hole Large-diameter stepped portion 17a at the upper end of 17
By doing so, the reservoir portion of the shell 39 becomes wider, and the effect of keeping the shell 39 in the fixing sleeve 19 is further improved than that shown in FIG.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, in a method for pouring molten metal into a mold in a horizontal mold clamping, vertical casting type die casting machine, a plunger is advanced within a casting sleeve to form a constriction at the lower part of a mold cavity. After performing injection while forming a thin cylindrical solidified material between the plunger tip and the plunger tip, the small diameter inner plunger is advanced to leave the solidified material in the surrounding space and only the molten metal is injected. The cylindrical solidified part that is formed along the inner circumferential surface of the casting sleeve during molten metal injection comes into contact with the boundary step between the constriction part and the vertical hole, and is compressed by the outer plunger tip. Even if the inner plunger tip is raised very close to the constriction, it may remain in the cylindrical space between the inner plunger tip and the inner peripheral surface of the vertical hole and may enter the mold cavity. As a result, the quality of cast products is significantly improved, and
Since it is possible to raise the plunger to the maximum extent without fear of solidified material entering, the amount of wasted biscuits attached to the cast product is reduced, and the product yield is improved.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of a horizontal die-clamping, vertical casting die-casting machine shown to explain the method of pouring molten metal into a mold according to the present invention, and FIG.
FIG. 3 is an enlarged sectional view of the part where molten metal is poured into the mold cavity, and FIGS. 4 and 5 are shown corresponding to FIG. 3 to explain other embodiments of the present invention. FIG. 3 is an enlarged cross-sectional view of a part for pouring molten metal into a mold cavity. 1...Die casting machine, 2...Horizontal clamping unit, 3...Vertical casting unit, 10...Fixed mold,
12...Movable mold, 14...Divided surface, 15...Cavity, 16...Neck part, 17...Vertical hole part, 18...Shell contact part, 19...Space part, 2
7...Plunger, 32...Cast sleeve, 33
...Outer plunger chip, 35...Inner plunger chip, 39...Ciel.

Claims (1)

[Claims] 1. By raising the outer plunger tip within the vertical casting sleeve and the vertical hole above the vertical hole, the vertical hole and the constriction above the vertical hole are moved into the cavity of the side-clamping mold located above the vertical hole. The molten metal in the casting sleeve is injected through the casting sleeve, and the cylindrical solidified molten metal produced during casting is compressed between the rising outer plunger tip and the horizontal surface of the step between the vertical hole and the constriction. At the same time, during the injection of the molten metal, an inner plunger tip having a smaller diameter than this is protruded from the upper end surface of the outer plunger tip to guide the cylindrical molten metal solidified material into the cylindrical space formed in the vertical hole. A method for pouring molten metal into a mold, which is characterized by completing injection while allowing the metal to remain trapped.