JPS6228057A - Molten metal casting device for vertical die casting machine - Google Patents

Abstract

PURPOSE:To improve the quality of a product by forming a large-diameter vertical hole continuous with a contracted part to a molten metal passage between a casting sleeve and cavity and further disposing an annular hollow groove to the specific position in the upper part of the vertical hole. CONSTITUTION:The cavity 50 is formed via split metallic molds 30, 33 and a cylindrical stationary sleeve 52 is fitted into a lower sleeve hole. The molten metal passage between the cavity 50 and the casting sleeve is formed of the small-diameter contracted part 54 and the vertical hole part 53 of the stationary sleeve 52. The annular hollow groove 55 is provided to the upper part of the stationary sleeve 52 and the size (t) of the position at the top end thereof is made <0.15 times the diameter of the hole part 53. A shell 58 intrudes into the hollow groove 55 from the molten metal 57 lifted by the rise of a plunger tip 42a. The shell intruded therein is buckled and is successively deposited. The intrusion of the shell 58 into the cavity 50 is thus prevented and the quality of the product is improved.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a molten metal pouring device for a vertical die casting machine that pours molten metal into the cavity of a clamped mold from directly below the mold. .

[Conventional technology]

A vertical die-casting machine is known as a type of die-casting machine, which casts the molten metal in the casting sleeve directly below into the cavity of a mold that has been clamped. Depending on the direction, they are further classified into vertical clamping molds and horizontal clamping molds.

This type of vertical die-casting machine is characterized by the fact that the length of the molten metal in the casting sleeve before casting is short and the temperature of the molten metal does not drop much. There is less mixing of air and gas in the casting sleeve, resulting in fewer cavities caused by gas in the casting sleeve, and the casting plunger faces the cavity when filling with molten metal, making pressure effective. such as being transmitted to
It has many excellent features and is widely used in various applications. However, in this type of die casting machine, the molten metal in contact with the inner peripheral surface of the υ casting sleeve solidifies due to the temperature drop during casting, and the solidified molten metal enters the cavity, impairing the quality of the product. There was a problem of lowering the

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. FIG. 6 is a sectional view of the molten metal casting part, and this will be explained based on the same figure. An open cylindrical fixing sleeve 4 is fitted into the fixing sleeve 4, and a cast-in sleeve 5, which has been raised by the lower cylinder, is joined to the lower end of the fixing sleeve 4. Fitted into the casting sleeve 5 is a plunger 6 that is moved up and down by a vertical casting injection cylinder.

A small diameter constriction 9 is formed between the cavity T of the molds 2 and 3 and the large diameter vertical hole 8 which is the inner hole of the fixed sleeve 4.

With this configuration, when the plunger 6 is advanced after pouring metal into the casting sleeve 5 in the lowered position and raising it to the position shown in the figure, the molten metal inside the casting sleeve 5 is moved forward. It is cast into the cavity 7 through the vertical hole 8 and the constriction 9.

Then, the shell 10, which is a thin cylindrical solidified material formed along the inner circumferential surface of the vertical hole 8 during casting, is inserted into the plunger 6.
The shell 10 is compressed into a bellows-like shape between the front part of the constriction part 9 and the flat surface of the stepped part in front of the constriction part 9, and then cast.
It is possible to prevent the intrusion into the cavity T by remaining inside the cavity T. A so-called biscuit 11, which is a solid substance left above the plunger 6, is attached to the product solidified after completion of casting and taken out from the cavity 7 via the solid substance in the constriction part 9. This can be easily removed by breaking off the thin solid material corresponding to No. 9.

[Problem that the invention seeks to solve]

However, in such a conventional molten metal casting apparatus, when the amount of molten metal is large and a large amount of shell 10 is generated, or when the shell 10 is thick, it is not possible to capture it with only the constriction part 9. However, a part of it may invade into the cavity T, and a satisfactory effect cannot necessarily be expected.

[Means for solving problems]

In order to solve these problems, in the present invention, the molten metal passage between the cavity and the casting sleeve is formed by a constricted part and a large-diameter vertical hole continuous below the constricted part. A groove was provided, and the height of the groove was set so that the upper end of the groove was located within 0.15 times the diameter of the vertical hole from the upper end of the vertical hole.

[Effect]

With this configuration, the solidified molten metal formed along the inner hole of the casting sleeve is compressed and buckled between the rising end face of the plunger tip and the step end face in front of the constricted part. When the solidified material breaks, the leading end of the solidified material is bent and trapped in the annular groove, causing it to accumulate in the groove, or solidification is delayed due to the heat insulating effect of the molten metal within the groove, causing it to become soft and break. When the concave groove captures the coagulated material, the condensed material is pushed into the concave groove just before the constriction, so it does not go directly to the constriction, but most of it is trapped in the concave groove and is deposited or broken. do.

〔Example〕

1 to 4 show an embodiment of the molten metal casting apparatus according to the present invention, FIG. 1 is a longitudinal sectional view thereof, FIG. 2 is an enlarged longitudinal sectional view of the main part of FIG. 1, and FIG. FIG. 2 is a vertical cross-sectional view of a horizontal clamping vertical die-casting machine that implements this process.

FIG. 4 is a sectional view along line AA in FIG. 3. In the figure, a die casting machine 21 is equipped with a horizontal mold clamping unit 22 and a vertical casting unit 23. 25, and an end platen (not shown) movably fixed to the other end of the machine base 24.

Reference numeral 26 denotes a column which connects the four corners of the fixed platen 25 and the end platen and is fixed with an oak 27.
A movable platen 28 is supported on B so as to be able to move forward and backward relative to the fixed platen 25, and a trouble mechanism 29 connects this movable platen 28 to a mold clamping cylinder (not shown) on the end platen side. . 30 is a fixed mold that is mounted on the fixed platen 25, whose movement in the vertical direction is restricted by a key 31, and which is positioned perpendicular to the plane of the paper by a key 32 provided vertically in the center of the fixed platen 25; A movable mold 33 is attached to the movable platen 28 and whose movement in the vertical direction is restricted by a key 34, and both molds 30 and 33 can be opened and closed in the horizontal direction with the dividing surface 35 as the boundary. is joined to.

Here, the reason why the vertical key 32 is provided between the fixed platen 25 and the fixed mold 30 on the center line of the machine is because the dividing surface 35 of both molds 30 degrees 33 is on the center line of the machine.
Casting sleeve 47 of vertical casting unit 23 provided below
(described later), etc., so that the horizontal center of the fixed mold 30 can be easily aligned.

On the other hand, a frame 36 of the vertical casting unit 23 is erected within a bit 37 provided below the mold clamp and supports the end of the machine space 24. A cast frame 39 connected to the side column 26 by four support rods 38 is provided close to the bottom surface of the pit 3γ. Reference numeral 40 denotes an injection cylinder rotatably supported by a cast frame 39, and a plunger 42 having a plunger tip 42m on its head is connected to the piston rod 41 via a coupling 43. The plunger 42 is activated by the hydraulic pressure of the injection cylinder 40.
is configured to move up and down.

44 is a block supported by fitting a pair of rams 45 implanted on the upper end surface of the injection cylinder 40 into ram holes, and the hole at the lower end engages with the piston rod 41; The block 44 is configured to be raised and lowered by pressure oil introduced into a cylinder 46 provided in the block 44- and by the lowering of the piston rod 41.

A cylindrical casting sleeve 4T is fixed to the upper end surface of the block 44, and when the block 44 is raised by the hydraulic pressure of the cylinder 46, the casting sleeve 4T and a fixed sleeve 52, which will be described later, are concentric with each other. When the block 44 is lowered, both sleeves 47 and 52
are arranged so that they are spaced apart. 48 is a tilting cylinder pivotally supported on the frame 36 side, the working end of the piston rod is pivotally attached to the injection cylinder 40, and the block 44 is lowered to open both sleeves 5.
By operating the tilting cylinder 48 with 2 and 4T separated, the entire vertical casting unit 23 is raised and tilted between the casting position shown in the figure and the inclined pouring position. It is composed of Reference numeral 49 denotes an adjustable stopper that abuts the injection cylinder 40 to limit its rotation toward the casting position.

Next, the molten metal casting apparatus will be explained. Both molds 30.
33 is provided with a cavity 50 having the same shape as the cast product and divided by a dividing surface 35.
A fixed sleeve 52 formed in a cylindrical shape is fitted into the sleeve hole 51 provided below, and the casting sleeve 4γ is inserted into a part of the single sleeve hole 51 when it is raised. It is joined to the fixed sleeve 52. The molten metal passage between the casting sleeve 4T and the cavity 50 is formed by a vertical hole portion 53 as an inner hole of the fixed sleeve 52, and a small diameter constricted portion 54 continuous above the vertical hole portion 53. Near the upper end of 53, a groove 55 formed in an annular shape with a square cross section is provided. As shown in FIG. 3, the vertical position of this groove 55 is t, where t is the dimension from the upper end of the vertical hole 53 to the upper end of the groove 55, and D is the diameter of the vertical hole 53. <oxo,ts. In Figure 2, 5T is the plunger tip 4
The figure shows the molten metal being pushed up by T, and the molten metal 5T is solidified by contacting the inner peripheral surfaces of both sleeves 4T and 52 and the end surface of the plunger tip 421 and being cooled. The bottom shows a cylindrical shell. The reason for setting t=o-0, 15D as described above is to ensure that the shell 58 is captured by the groove 55 when the shell 58 is pushed up by the plunger tip 42&. In other words, in the case of t>0.150, the concave groove 55
When the tip of the shell 58 that has entered inside pops out from the groove 55, it faces diagonally upward toward the constriction 54, and even when the plunger tip 42 rises, it enters the constriction 54 without being crushed by it. There are many risks. On the other hand, if t=o-0,150, even if the shell 58 comes out of the concave groove 55 and tries to move in the lateral direction where the constriction 54 is, it will be crushed by the pressing force from below and will not move in the lateral direction. <
<, the shell 58 rarely enters the constriction 54.

Furthermore, if the volume of the concave groove 55 is too small, the capturing capacity will be insufficient and it will not be possible to prevent the shell 58 from entering the cavity 50, and if it is too large, even if the shell 58 is completely captured, it will still not be filled. Because of the presence of such spots, fresh molten metal 57 is filled at the final injection end, reducing the yield of the molded product. The appropriate volume is 0.5 x D"mm' or more for the plunger tip diameter φD" and 50
XD” is in the range of 83 or less.

The lower limit is the volume (v+ho) of the shim 58 produced when the sleeve temperature is relatively high in the case of a molded product with the minimum amount of hot water.

Lm x Nijiru 59 (D circumference: H Height of Nijiru 58; t mm Thickness of Nijiru 58, then V, =
LXlXt = πx Dx 0.5 X D x 0.3#0.5X
The upper limit of Dm' is the volume (V+-) generated when the sleeve temperature is relatively low in the case of a molded product with the maximum amount of hot water.

V, = LXHXt = πXDX3XDX5 -50XDI! l' Also, regarding the dimensions of the groove 55, if the depth is too large compared to the width, the shell 58 will not be able to fully penetrate into the deep part of the groove 55, and if the depth is shallow compared to the width, the shell 58 will not be able to fully penetrate into the depth of the groove 55. Since the effective space for the deposition of the concave groove 55 decreases and the effective deposition within the concave groove 55 is reduced, if the depth of the concave groove 55 is A9 and the width is B, then the ratio A:B is 5=1 to 0. It is effective to set the ratio to about 5:1.

The casting operation of the die casting machine configured as above will be explained. When the fixed mold 30 and the movable mold 33 are respectively attached to the fixed platen 25 and the movable platen 2B and the piston rod of the mold clamping cylinder is moved forward, the movable platen 2 which was in the mold open position
8 is moved to the illustrated mold clamping position via the trouble mechanism 29, and mold clamping is performed. During this mold clamping, the injection cylinder 4
Since the piston rod 41 of No. 0 has been lowered to the position shown in Figure 3, and the block 44 has been lowered further than the position shown in Figure 3, and both sleeves 52 and 47 are separated, the tilting cylinder When the piston rod 4B is advanced, the entire vertical casting unit 23 tilts, and the casting sleeve 41 comes out from below the fixed platen 25. Set and cast sleeve 4T
After pouring the molten metal 51 into the cylinder 46 of the block 44, the tilting cylinder 4B is operated again to vertically raise the vertical casting unit 23, and the doffing is fed into the cylinder 46 of the block 44. rises and the casting sleeve 47
is concentrically pressed against the lower surface of the fixed sleeve 52.

After this, pressure oil is introduced into the injection cylinder 40 to raise the tech stone rod 41, and the plunger 42 is raised via the coupling 43 to fill the cavity 5 of the mold 30°33.
0 into the casting sleeve 47 (iD). Prior to this casting, the molten metal 5γ in contact with the inner wall surface of the casting sleeve 7'47 and the sharp tip surface of the plunger tip 42 is cooled. Solidification occurs, and a shell 58 formed in the shape of a thin cylinder with a bottom is generated.This shell 58 rises together with the plunger tip 42&, and as shown in FIG. The tip touches or bends and enters the groove 55. In this case, if the groove 55 is at a low position, the tip and lower part of the shell 58 are sucked into the groove 55, causing the bent tip to become a constriction. If the shell 58 is turned in the direction of 54, the shell 58 may enter the constriction 54, but in this device, the vertical position of the groove 55 is set near the upper end where t is DXo, 15 or less. Therefore, the tip of the shell 58 reliably enters into the groove 55. When the plunger tip 42m further rises from this state, a bellows-like formation occurs between the shell 58Vi plunger tip 42& and the shell contact surface 59 in the groove 55. The shell 5B buckles and breaks, and without expelling the molten metal in the groove 55, it accumulates sequentially from the bottom to the top in the groove 55. In this case, the shell 5B will surely enter the groove 55. However, most of the shell/v5B is deposited and remains in the groove 55, and there is very little risk of it entering the constriction 54.

In addition, the shell 5B passes through the groove 58 during injection.
When the shell 58 is broken at the groove 55, air is formed in the groove 55, and this reduces the role of the heat insulating layer, so the shell 58 becomes somewhat soft. Note that during injection, a small portion of the shell 58 may break off into small pieces and enter the constriction 54 and into the cavity 50, but in that case, since the shell 58 is quite small, it will not affect the quality of the product. does not affect
Enough cast products with good surface conditions can be obtained.

FIG. 5 is a relationship diagram between the plunger tip position and load during injection operation, showing a comparison between a conventional fixed sleeve 52 that does not have a groove 55 in the middle and a structure of the present invention that has a groove 55. Here, the dotted line represents a conventional diagram, and the solid line represents a diagram of the present invention. However, the plunger tip position S is defined as O, which is the position of the plunger tip 421L where the tip of the molten metal 5γ contacts the lower end position of the constriction 54 of the mold, that is, the shell contact surface 59, and the upper side is positive and the lower side is negative. expressed. Also, load 'r
'd % Expressed as output of injection cylinder.

As can be seen from FIG. 5, when the fixed sleeve 52 has the groove 55 as in the present invention, the mold cavity 50
Ideally, almost no load is applied to the plunger tip 42& until just before the molten metal 5T is sufficiently filled in the plunger tip 42, and then the load increases rapidly just before the filling is completed, and the casting is completed when the molten metal 5γ is completely filled. It shows the typical load curve and filling condition.

On the other hand, if the fixed sleeve 4 does not have a concave groove as in the conventional case, once the molten metal 11 starts to enter the mold cavity, the load will gradually start to be applied and the load will increase quickly. Then, the load reaches its maximum value before the plunger tip 6 has risen to the filling completion position. this is,
This indicates that the molten metal 11 is not sufficiently filled into the mold cavity. In other words, this indicates that a defective cast product with chipped parts has been produced. This state is thought to be due to the fact that the solidified layer is not sufficiently captured before reaching the constriction 9 and enters the cavity as a relatively large lump, preventing smooth flow and force transmission.

In this way, when the groove 55 is provided in the fixed sleeve 52,
Good water flow, no large solidified layer, and high quality, high strength cast products can be easily obtained.

The molten metal 5T is poured in this way, and after the molten metal 5T filled in the cavity 50 is solidified and cooled, the pressure oil in the injection cylinder 40 is removed, the plunger 42 is lowered, and the mold clamping cylinder is closed. One cycle is completed by moving the movable platen 2B away from the fixed platen 25 by retracting the piston rod to open the mold, and extruding the cast product by the product extrusion device 60.

Although this embodiment shows an example in which the groove 55 is provided slightly below the upper end of the vertical hole 53, the dimension indicated by the symbol t in FIG. 2 is set to O so that the groove 55 opens upward. It may be provided as follows.

〔Effect of the invention〕

As is clear from the above description, the present invention provides a molten metal casting device for a vertical die casting machine, in which a molten metal passage between a mold cavity and a casting sleeve is connected to a constricted portion and a large-diameter tube that continues below the constricted portion. An annular groove is provided at the top of the vertical hole, and the height of the groove is set so that the upper end thereof is 0.1 of the diameter of the vertical hole from the upper end of the vertical hole.
By setting the positions within 5 times, the solidified material of the molten metal produced by cooling in the vertical hole is bent outward at its upper end without heading toward the constriction as the plunger rises. Since it reliably enters the groove, is captured and deposited in the groove, there is no risk of it entering the mold cavity, and an extremely healthy cast product can be obtained.

[Brief explanation of the drawing]

1 to 5 show an embodiment of a molten metal pouring device for a vertical die casting machine according to the present invention, FIG. 1 is a longitudinal sectional view thereof, and FIG. 2 is an enlarged longitudinal sectional view of the main part of FIG. 1. , Fig. 3 is a vertical cross-sectional view of a horizontal clamping vertical die-casting machine that implements this, Fig. 4 is a cross-sectional view taken along the line AA in Fig. 3, and Fig. 5 is a diagram showing the relationship between plunger tip position and load during injection operation. , FIG. 6 is a longitudinal sectional view of a conventional molten metal casting device of a vertical die casting machine. 21 φQ tie casting machine, 30... fixed mold, 33φφ... movable mold, 47--... casting sleeve,
50... @ψ cavity, 52... fixed sleeve,
53...Vertical hole part, 54 fist-...constriction part, 55.
...-concave groove, 5γ...molten metal, t...distance between the upper end of the vertical hole and the upper end of the groove, D...diameter of the vertical hole.

Claims (1)

[Claims] In a molten metal casting device for a vertical die casting machine that pours molten metal in a vertical casting sleeve into a cavity of a clamped mold from directly below, a molten metal passage between the cavity and the casting sleeve is formed. It is formed by a constriction and a large-diameter vertical hole continuous below the constriction, and an annular groove is provided at the top of the vertical hole, and the height of the groove is set such that the upper end of the concave groove is the same as that of the vertical hole. A molten metal casting device for a vertical die casting machine, characterized in that the device is set to be located within 0.15 times the diameter of the vertical hole from the upper end.