JPH0429461B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a molten metal casting 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 dies and horizontal clamping dies.

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. The amount of gas-induced cavities in the casting sleeve is small due to less mixing with air, 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 that comes into contact with the inner circumferential surface of the casting sleeve solidifies due to the temperature drop during casting, and this molten metal solidification enters the cavity, reducing the quality of the product. There was a problem.

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 cross-sectional view of the molten metal casting part, and this will be explained based on this figure.The fixed mold 2 and the movable mold 3 of the horizontal clamping mold, which are joined at the dividing surface 1, have two halves. A split cylindrical fixing sleeve 4 is fitted, and a casting sleeve 5 that has been raised by the lower cylinder is joined to the lower end of the fixing sleeve 4. Casting sleeve 5
A plunger 6 that moves forward and backward in the vertical direction is fitted inside by a vertically cast injection cylinder. A small diameter constriction 9 is formed between the cavity 7 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 which is 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. A shell 10 is formed as a thin cylindrical solidified material along the inner peripheral surface of the vertical hole 8 during casting.
By compressing the shell 10 into a bellows-like shape between the plunger 6 and the step plane in front of the constriction 9, the shell 10 remains in the vertical hole 8 and prevents it from entering the cavity 7. can do. After the casting is completed, the product solidified and taken out from the cavity 7 is attached with a so-called biscuit 11, which is a solid substance left above the plunger 6, 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 conventional molten metal casting equipment, when the amount of molten metal is large and a large amount of shell 10 is generated, or when the thickness of shell 10 is thick, it is difficult to capture it with only the constriction part 9. However, a part of the liquid may enter the cavity 7, 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 between the rising end face of the plunger tip and the stepped end face in front of the constriction, causing buckling and rupture. However, the tip of the solidified material may be bent and trapped in the annular groove, causing it to accumulate in the groove, or solidification may be delayed due to the heat insulating effect of the molten metal within the groove, causing the soft material to break. When the concave groove captures the coagulated material, the coagulated material is pushed into the concave groove just before the constriction, so it does not go directly to the constriction, and most of it is trapped in the concave groove and is deposited or broken.

〔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, and FIG.
The drawings are an enlarged vertical cross-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 in which this was implemented, and FIG. 4 is a cross-sectional view AA of 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. A column 26 connects the four corners of the fixed platen 25 and the end platen and is fixed with nuts 27. A movable platen 28 is supported on this column 26 so as to be able to move forward and backward with respect to the fixed platen 25. The movable platen 28 and a mold clamping cylinder (not shown) on the end platen side are connected by a toggle mechanism 29. 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; Reference numeral 33 denotes a movable mold which is mounted on the movable platen 28 and whose movement in the vertical direction is regulated by a key 34.
33 are joined so as to be openable and closable in the horizontal direction with the dividing surface 35 as a boundary. Here, the vertical key 32 is provided between the fixed platen 25 and the fixed mold 30 on the center line of the machine because it is provided below the dividing surface 35 of both molds 30 and 33 on the center line of the machine. Casting sleeve 47 of the vertical casting unit 23
(described later), etc., so that the horizontal center of the fixed mold 30 can be easily aligned.

On the other hand, the frame 36 of the vertical casting unit 23 is
It is erected in a pit 37 provided below the mold clamp and supported by the end of the machine base 24, and inside this frame 36, four support rods are installed between it and the lower column 26. A cast frame 39 connected at 38 is provided adjacent to the bottom surface of the pit 37. Reference numeral 40 denotes an injection cylinder rotatably supported on a cast frame 39, and a plunger 42 having a plunger tip 42a on its head is connected to the piston rod 41 via a coupling 43, and the injection cylinder The plunger 42 is configured to be raised and lowered by hydraulic pressure of 40. Reference numeral 44 denotes 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 moved up and down by pressure oil introduced into a cylinder 46 provided at the block 44 and by the lowering of the piston rod 41.

A cylindrical casting sleeve 47 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 47 and a fixed sleeve 5, which will be described later, are connected to each other.
2 are concentrically pressed together, and when the block 44 is lowered, both the sleeves 47 and 52 are separated. What is indicated by the symbol 48 is
It is a tilting cylinder that is pivotally supported on the frame 36 side, and the working end of its piston rod is pivotally connected to the injection cylinder 40, and it can be tilted when the block 44 is lowered and both sleeves 52 and 47 are separated. By operating the cylinder 48, the entire vertical casting unit 23 is configured to rise and tilt between the casting position shown in the figure and the inclined pouring position. Reference numeral 49 denotes an adjustable stopper that abuts the injection cylinder 40 and restricts the limit of rotation toward the casting position.

Next, the molten metal casting apparatus will be explained. Both molds 30 and 33 are provided with cavities 50 having the same shape as the cast product and separated by a dividing surface 35, and a sleeve hole 51 provided below this cavity 50 has a cylindrical shape. The formed fixing sleeve 52 is fitted, and the casting sleeve 47 is inserted into a part of the sleeve hole 51 when raised and joined to the fixing sleeve 52. The molten metal passage between the casting sleeve 47 and the cavity 50 is
Vertical hole 53 as inner hole of fixing sleeve 52
and a small-diameter constriction 54 that continues above the constriction, and near the upper end of the vertical hole 53,
A groove 55 formed in an annular shape with a square cross section is provided. As shown in FIG.
When the diameter of is D, it is set so that t<D×0.15. In FIG. 2, reference numeral 57 indicates the molten metal being pushed up by the plunger tip 47, and 58 indicates the molten metal 57 being pushed up by the plunger tip 47.
52 and the end surface of the plunger tip 42a and solidified by being cooled. In addition, the reason why t=0 to 0.15D as mentioned above is because of the plunger tip 4.
This is to ensure that the shell 58 is captured by the concave groove 55 when the shell 58 is pushed up by the groove 2a. That is, in the case of t>0.15D, when the tip of the shell 58 that has entered the groove 55 pops out from the groove 55, it moves into the constriction 5 diagonally upward.
It will head in 4 directions, plunger tip 42
Even if a rises, there is a high possibility that it will not be crushed by this and will enter the constriction 54. On the other hand, t=
If the value is 0 to 0.15D, even if the shell 58 comes out of the concave groove 55 and tries to move laterally toward the constriction 54, it will be crushed by the pressure from below and will have difficulty moving laterally, and the shell 58 will not move toward the constriction 54. I almost never get into it.

Furthermore, if the volume of the concave groove 55 is too small, the trapping capacity will be insufficient and the cavity 5 of the shell 58 will be
If the shell 58 is too large, even if the shell 58 is completely captured, there will still be unfilled areas, which will be filled with fresh molten metal 57 at the final injection end, reducing the yield of the molded product. This will lower the The appropriate volume is in the range of 0.5×D ² mm ³ or more and 50×D ² mm ³ or less with respect to the plunger tip diameter φDmm.

The lower limit is shell 5, which is generated when the sleeve temperature is relatively high in the case of a molded product with the minimum amount of hot water.
It has a volume of 8 (V ₁ mm ³ ).

Lmm: circumference of shell 58; Hmm: height of shell 58; amm: thickness of shell 58, V ₁ = L x H x a = π x D x 0.5 x D x 0.3 ≒ 0.5 x D mm ³ The upper limit is This is the volume (V ₁ mm ³ ) generated when the sleeve temperature is relatively low in the case of a molded product with the maximum amount of molten metal.

V ₁ = L x H x a = π x D x 3 x D x 5 ≒ 50 x D mm ³ Regarding the dimensions of the groove 55, if the depth is deep relative to the width, the shell 58 will be able to fully cover the groove 55. In addition, if the depth is shallow compared to the width, the effective space for depositing 58 will be reduced, making it impossible to effectively deposit inside the groove 55. Assuming that the length is A and the width is B, it is effective to set the ratio A:B to about 5:1 to 0.5:1.

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 28 and the piston rod of the mold clamping cylinder is advanced, the movable platen 28 which was in the mold open position is moved through the toggle mechanism 29. The mold is moved to the illustrated mold clamping position and mold clamping is performed. During this mold clamping, the piston rod 41 of the injection cylinder 40 has been lowered to the position shown in Figure 3, and the block 44 has been lowered than the position shown in Figure 3, so that the sleeves 52 and 47 are separated. Therefore, when the piston rod of the tilting cylinder 48 is advanced, the entire vertical casting unit 23 tilts, and the casting sleeve 47 comes out from below the fixed platen 25. After injecting the molten metal 57 into the casting sleeve 47 by squeezing or the like, the tilting cylinder 48 is operated again to vertically raise the vertical casting unit 23, and pressure oil is sent into the cylinder 46 of the block 44. When inserted, 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 piston rod 41, and the plunger 42 is raised via the coupling ring 43 to inject the mold 3.
Sleeve 47 cast into cavity 50 of 0.33
The molten metal 57 inside is poured. Prior to this casting, the molten metal 57 is in contact with the inner wall surface of the casting sleeve 47 and the tip surface of the plunger tip 42a.
is solidified by cooling, and a thin shell 58 formed in the shape of a cylinder with a bottom is generated. This shell 58 rises together with the plunger tip 42a, and as shown in FIG. 2, the tip comes into contact with the shell abutment surface 59 in front of the constriction 54, or bends and enters the groove 55. In this case, if the position of the groove 55 is low, the groove 5 will be slightly lower than the tip of the shell 58.
The shell 58 may enter the constriction 54 when the shell 58 is sucked into the concave groove 54 and its bent end faces toward the constriction 54. However, in this device, the shell 58
Since the vertical position of the shell 58 is set near the upper end where t is equal to or less than D×0.15, the tip of the shell 58 reliably enters the groove 55. When the plunger tip 42a further rises from this state, the shell 58
is buckled and bent in a bellows-like manner between the plunger tip 42a and the shell contact surface 59 in the groove 55, and is deposited sequentially from the bottom to the top in the groove 55 while expelling the molten metal in the groove 55. To go. In this case, since the shell 58 reliably enters the groove 55, most of the shell 58 is deposited and remains within the groove 55, and there is very little risk of it entering the constriction 54.

Furthermore, when the shell 58 passes through the groove 58 or breaks at the groove 55 during injection, there is air inside the groove 55, which acts as a heat insulating layer.
Shell 58 becomes somewhat softer. In addition, at the time of 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, the shell 58 is quite small, so it will not affect the quality of the product in any way.
Enough cast products with good surface conditions can be obtained.

FIG. 5 shows a concave groove 55 in the middle of the fixed sleeve 52.
A relationship diagram between the plunger tip position and the load during injection operation, showing a comparison between a conventional one without a groove and a one of the present invention with a concave groove 55, where the dotted line indicates the diagram of the conventional one and the solid line shows a diagram of the invention. However, the plunger tip position S is determined by setting the position of the plunger tip 42a where the tip of the molten metal 57 contacts the lower end position of the constriction 54 of the mold, that is, the shell contact surface 59, to be 0, the upper part being positive, and the lower part being negative. expressed. Moreover, the load T was expressed by the output of the injection cylinder.

As can be seen from FIG. 5, when the fixed sleeve 52 has the concave groove 55 as in the present invention, the plunger tip 42a is almost completely filled with the molten metal 57 until the mold cavity 50 is sufficiently filled with the molten metal 57. This shows an ideal load curve and filling state in which no load is applied, the load increases rapidly just before filling is completed, and the molten metal 57 is completely filled and casting is completed.

On the other hand, as in the conventional case, the fixed sleeve 4
If there is no groove, when the molten metal 11 starts to enter the mold cavity 7, 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 been raised to the filling completion position. This is molten metal 11
indicates that the mold cavity 7 is not sufficiently filled. 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 the constriction 9 and enters the cavity 7 as a relatively large lump, preventing the smooth flow of the melt and the transmission of force.

By providing the groove 55 in the fixed sleeve 52 in this manner, the hot water flow is good, a large solidified layer does not form, and a cast product of high quality and high strength can be reliably and easily obtained.

The molten metal 57 is poured in this way, and after the molten metal 57 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. By retracting the piston rod, the movable platen 28
is moved away from the fixed platen 25 to open the mold, and the product extrusion device 60 extrudes the cast product, thereby completing one cycle.

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 0 to open the groove 55 upward. It may be provided as follows.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, in the molten metal pouring device for a vertical die casting machine, the molten metal passage between the mold cavity and the casting sleeve is formed by a large-diameter tube continuous to the constriction part and below the constriction part. An annular groove is provided at the top of the vertical hole, and the height of the groove is such that the upper end of the groove is located within 0.15 times the diameter of the vertical hole from the upper end of the vertical hole. With this setting, the solidified molten metal generated by cooling in the vertical hole is bent outward at its upper end without heading toward the constriction due to the rise of the plunger, and is thereby ensured to enter the groove. invade,
Since it is trapped 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 drawings]

1 to 5 show embodiments of a molten metal casting device for a vertical die-casting machine according to the present invention.
The figure is a vertical cross-sectional view of the machine, Figure 2 is an enlarged vertical cross-sectional view of the main part in Figure 1, Figure 3 is a vertical cross-sectional view of a horizontal clamping vertical die-casting machine that implements this, and Figure 4 is the AA of Figure 3.
5 is a diagram showing the relationship between the position of the plunger tip and the load during injection operation, and FIG. 6 is a longitudinal sectional view of a conventional molten metal casting device for a vertical die casting machine. 21... Die casting machine, 30... Fixed mold, 33... Movable mold, 47... Casting sleeve,
50... Cavity, 52... Fixed sleeve, 5
3... Vertical hole, 54... Constriction, 55... Concave groove, 57... 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] 1. In a molten metal casting device of 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 by a constriction and a large-diameter vertical hole continuous below the constriction, and an annular groove is provided above the vertical hole, and the height of the groove is set so that the upper end of the groove is equal to the height of the vertical hole. A molten metal casting device for a vertical die casting machine, characterized in that the device is positioned within 0.15 times the diameter of the vertical hole from the upper end of the vertical die casting machine.