JPS61229456A - Vertical injection device for die casting machine - Google Patents

Abstract

PURPOSE:To produce a die-cast product having good quality without blowholes in a vertical type injection device for a die casting machine by venting the gas fro the inside of a die cavity while a molten metal is supplied into an injection sleeve and press-feeding the molten metal into the cavity by a plunger. CONSTITUTION:A stationary die 11 and a movable die 12 are clamped to form the dies provided with the cavity 14 for casting and a contracted part 15. The injection sleeve 22 having an injection hole 16 is fitted to the dies and the plunger 20 connected to the injection cylinder 18 is inserted into the injection sleeve 22. The molten metal for casting is put into the injection sleeve 22 and the sleeve 22 is engaged with a stationary sleeve 17 in the upper part. The air in the cavity is sucked from a die venting device 47 into a vacuum tank 66 via solenoid valves 70, 74 by which the inside of the cavity is degassed. The plunger 20 connected to the piston rod 19 of the injection cylinder 18 is thereafter raised to press-cast the molten metal in the injection sleeve into the cavity 14. The die-cast product having no defects such as blowholes is thus obtd.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention is a vertical casting type die casting machine, in which the injection sleeve is fully inserted into the injection hole of the mold, and the molten metal in the injection sleeve is poured into the cavity of the mold. Article 6 relates to a vertical injection device for injecting to.

[Conventional technology]

Casting using a die-casting machine has traditionally been widely used as a method for manufacturing precision products in large quantities, but this type of casting machine uses molten metal N4 to fill the mold cavity at high speed and high pressure. The gas in the cavity may not be sufficiently vented and may mix with molten metal and remain in the product as cavities, so it may not be suitable for products where integrity without cavities is important.

In order to eliminate all of these inconveniences, the present applicant has proposed in Utility Application No. 107265/1983 that a sound die-cast product can be obtained without gas turbulence and gas entrainment inside the mold during casting. We proposed the complete development of a degassing device for Kingi.

This device is equipped with a gas vent valve in the gas exhaust path leading from the mold cavity to outside Venus, and when the valve is open, the gas is injected into the cavity above the molten metal, and the gas with a small mass in the cavity is exhausted. When the gas has been discharged through the gas passage, the inertial force of the molten metal which has entered the gas discharge passage from inside the cavity and has a large specific mass is applied to the valve to close it. Even if it is made of a mold, it is possible to vent gas inside the mold without any leakage.

The present applicant has also developed a reduced pressure or vacuum type die casting method and its apparatus, which actively exhausts the gas in the mold cavity by connecting the gas exhaust path to the total vacuum generating device. This reduced pressure die casting method reduces the pressure by sucking in an amount of gas from the outside that is greater than the amount of gas that flows into the cavity from outside Venus through the gap, thereby ensuring that the gas inside the mold is removed. It can be done.

[Problem that the invention seeks to solve]

However, in such a conventional injection device,
When injecting while the inside of the mold cavity is evacuated from above, outside air is sucked in from the joint of the injection sleeve, causing the solidified layer that forms at the tip of the plunger tip to break off during injection. At that time, we had to take six precautions due to a problem in which air from the joint of the injection sleeve entered the molten metal and entered the mold cavity along with the molten metal.

That is, as shown in FIG. 8, which is a cross-sectional view of the injection sleeve insertion part, a fixed sleeve 5 is fitted into the injection hole part 4 of the mold 3 having a cavity 1 and a constriction part 2, and the injection sleeve 5 is inserted into the injection hole part 4. For this purpose, an injection sleeve T supplied with molten metal 6 is inserted, and a plunger tip 8 is slidably inserted into the inner hole of the injection sleeve T. At the start of injection, a solidified layer 9 is generated by the solidification of the molten metal 6 on the molten metal contacting end surface of the plunger tip 8 and the inner surface of the injection sleeve 7 that is continuous with this, and this solidified layer 9 is formed by the plunger which rises during injection rounding. 8, the biscuit is compressed and crushed between the flat surface 10 in front of the constriction 2 and the end face of the plunger tip 8, and the solidified molten metal 6 flows into the fixed sleeve 5 without entering the cavity 1. When the product is removed, the constriction 2 remains with the product.
It is separated from the biscuit together with the biscuit.

However, in the conventional injection device described above, when the gas gold in the cavity 1 is vacuum-suctioned, the injection hole 4 of the gold m3 is
Air is sucked from the gap between the fixed sleeve T and the injection sleeve 7 inserted therein as shown by the arrow in the figure, and this air enters between the inner surface of the fixed sleeve T and the solidified layer N9, while the solidified layer 9 is inserted into the plunger. When the solidified N9 is compressed by the chip 8 and hits the flat surface 10, as shown by the reference numeral 9A in the figure, it is broken one after another, and the air enters the molten metal from between the broken solid pieces 9A. It passes through the entire molten metal and enters the cavity 1 from the constriction 2. Since the air and the molten metal alternately pass through the constricted portion 2, the flow of the molten metal is disturbed, resulting in a disadvantage that a cast product of good quality cannot be obtained.

[Ninth way to solve the problem]

In order to solve these problems, the present invention provides a vacuum suction device (1t) for supplying molten metal into the injection sleeve and then sucking the gas inside the mold cavity, and also provides a vacuum suction device (1t) for sucking the gas inside the mold cavity. A space section connected to a vacuum suction device is provided between the injection sleeve and the abutting surface of the injection hole section, and a seal section is provided between the injection sleeve tip surface and the contact surface of the injection hole section.

[Effect]

The advantage of this structure is that by drawing a vacuum from the outer surface of the injection sleeve and degassing the inside of the mold cavity, degassing is promoted and a solidified layer of molten metal is formed on the molten metal contacting end surface of the plunger tip. Even if this occurs and the plunger tip is pushed up by the rise of the plunger tip, causing it to break on a flat surface, air will be sucked in from between the injection hole and the injection sleeve, and outside air will not be sucked in from here. , Air does not mix into the molten metal, and air does not enter the mold cavity.

[Example] Figures 1 to 7 show an example of the vertical injection device for a die-casting machine according to the present invention. Fig. 3 is an AA sectional view of Fig. 2, Fig. 4 is a BB sectional view of Fig. 2, and Fig. 5 is a CCC sectional view of Fig. 2. The longitudinal sectional view, FIG. 7, is a DDIFr plane view of FIG. 6. In the figure, a fixed mold 11 and a movable mold 12 are joined and clamped at a dividing surface 13. Inside thereof, a cavity 14, a constriction 15, and an injection hole 16 are formed on the dividing surface 13. A fixed sleeve 1T is fitted into the injection hole 16 formed on both sides of the injection hole 16. Book*
The die-casting machine of the example is Yokoya tightening, vertical casting star's movable mold 12 is moved horizontally, F-warm tightening is carried out, and the injection cylinder 1B is mold 11.
．． It is located directly below 12. The injection cylinder 18 is equipped with a piston rod 19t which moves forward and backward under hydraulic pressure, and a plunger 20, shown in detail in FIGS.

Reference numeral 22 denotes an injection sleeve formed to have the same diameter as the fixed sleeve 17, and which is moved up and down by a cylinder (not shown) and inserted into and removed from the fixed sleeve 17. A plunger tip 23 with 20 head i is slidably fitted, and the casting sleeve 22 is completely fixed.
The plunger tip 23 is inserted into the J-tub 1T and then tilted together with the injection cylinder 18 by a tilting cylinder (not shown) to inject molten metal into the casting sleeve 22. After pouring, the injection cylinder 1B is erected, the casting sleeve 22 is inserted into the fixed sleeve 17, and the piston rod 19 is advanced by hydraulic pressure.
Plunger tip 23 injects molten metal into cavity 14.

Therefore, the plunger 20 will be explained in detail. A plunger rod 24 connected to the piston rod 19 by a coupling 21 has a screw hole 24a and a pressure reducing pipe support hole 24.
b1 Air passage hole 24C1 is formed in a step shape at the bottom of the bottom hole (not shown) and is equipped with an inner hole.The uppermost threaded hole 24a
K is screwed in all the way until the lower threaded portion 25a of the threaded pipe 25 stops at the stepped portion. A pair of upper and lower adapters 26 and 27 are loosely attached to the central threadless portion 25b of the threaded pipe 25, and the plunger tip 23 and the plunger rod 2 are screwed into the upper threaded portion 25c of the threaded pipe 25.
It is clamped and fixed with 4. Reference numeral 28 denotes a decompression tube consisting of a holding cylinder (not shown) at the lower end and nine tubes 28a welded to the holding cylinder, which is inserted from the bottom hole 24dlIll and the holding cylinder is fitted into the upper end of the bottom hole (not shown) at the lower end of the plunger rod. V28a is the air passage hole 24
ck penetrates and the upper part is fitted into the pressure reducing tube support hole 24b. A water-cooled tube 29 is held at the lower end of the plunger rod 24 and passes through the holding tube/pipe 28a1 and the threaded tube 25, and its tip is connected to the space 23a of the plunger tip 23.
It's coming inside. 30 is the 01J ring provided at various places as a sealing material.

Annular groove 23b provided on the outer periphery of plunger tip 23
The annular groove 26a provided in the adapter 26 is communicated with an air passage 23c, and the annular groove 27a provided in the adapter 27 is communicated with an air passage 27b provided in the full-mesh filter 31.

The air passage holes 24c and [28b] of the plunger rod 24
An air passage 33 communicates between the air passage 32 formed between the ring u27a and the annular u27a. A pipe 35 provided in a flexible section 34 of a circuit (described later) is connected.

On the other hand, the lower end opening of the water cooling pipe 29a is connected to a cold water inlet (not shown) at the lower end of the plunger rod 24 via a cold water passage, an annular groove, etc., and the upper end opening is
The plunger rod 2 is passed through the space 23a and the cold water passage 36 and water channel that extend downward around the pipe 29a.
4 is communicated with a cold water outlet (not shown) at the lower end. The cold water inlet is connected to a pump or the like by a flexible hose or the like, and the cold water is supplied to the cold water inlet by the operation of the pump, rises in the pipe 29a, fills the space 23a, cools the plunger tip 23t, and then cools the plunger tip 23t. Afterwards, it flows down the cold water passage 36 and is drained from the cold water outlet.

Next, the mold degassing device will be explained. Both molds 1
At the outer part of the cavity 13 of 1.12, there is a gas venting path 40' and a gas venting groove 41 communicating with the dividing surface 140.
A mold degassing device, which is formed on both sides and is designated as a whole by reference numeral 42, is located directly above the gas venting groove 41 and is fixed to the movable mold 12. That is, a cylinder 44 is attached to the upper end of the next bracket 43 that is fixed to the movable mold 12, and a cylindrical spool 46 is attached to the flange portion of the lower end 7 held by the working end of a piston mid 450 that moves back and forth using the fluid pressure. is fixed by engaging its lower end into the circular hole in the upper end face of both metal fittings 11 and 12 so as to be freely inserted and removed. and,
During mold clamping and mold opening, the spool 46 is connected to the mold 11.1 via the piston rod 45t by the operation of the cylinder 440.
It is configured to be inserted into and removed from 2. Below the spool 46 inserted into the molds 11 and 12, there is a valve chamber 47, and a valve chamber 47. A bypass 48 is provided to communicate the gas vent passages 40, and a valve seat 49 facing the valve chamber 47 is formed on the lower end surface of the spool 46. Both rod portions 51a of a return rod 51 are slidably engaged with a pair of elongated holes 50 provided on the same outer wall of the spool 46, and between the return rod 51 and the flange portion of the piston rod 45. Return rod 51''Ij!: Members such as a tension spring 52, cylinder, solenoid device, gravity device, etc. that urge upward are suspended. Below the return rod 51,
A valve guide 53 integrally formed with a cylindrical portion 53a and a pair of screw hole portions 53b is engaged with the screw hole portion 53b and the full length hole 50 so as to be movable up and down, and is fixed with a bolt 54 and a nut 55. A valve rod 56 whose upper end threaded portion is screwed into a screw hole of the return rod 51 is slidably supported on the cylindrical portion 53a. A valve body 56a is provided at the lower end of the valve stem 56 and seats on the valve seat 49 when the valve stem 56 rises. When seated, it is configured to shut off the inner chamber of the spool 46, the gas vent #41, and the bypass 48. Reference numeral 57 denotes a ball that engages with the groove 56b of the valve stem 56 under the bias of the compression coil spring 58. These balls form a locking mechanism, and the valve body 56a is closed when the pressure of the molten metal is applied to the external force. t
It is configured so that it will not open again unless it reaches 710.

Note that the valve body 56a is opened by pushing down the rod portion 51a of the return rod 51. Reference numeral 59 is a stopper fixed to the bracket 43 for regulating the upper limit of the rise of the spool 46 which is raised by the operation of the cylinder 44. An exhaust hole 60 is opened at the lower end of the spool 46.
This exhaust hole 6.0 is connected to a pipe 61 of a pneumatic circuit (described later) shown in FIG.

The injection sleeve 22 into which the plunger tip 23 of the granger 20 as described above is slidably inserted is removably fitted into the injection hole 16 of the mold 11, 12 described above. The fitting upper end surface 22b and the fixed sleeve 1T are in contact with the injection sleeve. A gasket 17b, which is made of a heat-resistant material such as copper or asbestos and is formed into a half-ring shape and serves as a security seal, is fixed to the fixed sleeve 17 and interposed between +17m and +17m. Further, an annular groove 1 is provided between the injection sleeve 22 inserted into the injection hole 16 and the injection hole 16.
1m, 12a are provided in half on the molds 11 and 12 side, and an air passage 1 is provided in the annular groove 11a on the fixed mold 11 side.
1b is communicated and opened to the outside of the mold, and a pipe T5 shown in FIG. 1 is connected to this opening.

Next, the pneumatic circuit between the plunger 20 and the gas venting device [42] will be explained based on FIG. vacuum pump 62
The piping 63 connected to the piping is branched into a piping 64 and a piping 65 in the middle, and a vacuum tank 66 and an auxiliary vacuum tank 67 are provided on the piping 63 and 64, respectively. 63 and 64 are respectively connected to the pipes 61 and 35 via filters 6B and 69'.

Solenoid valves 70 and 71 are respectively disposed on the pipes 64 and 65, and when the solenoid of the solenoid valve 70 is energized from the state shown in the figure, the air in the plunger 20 is sucked, and the fc'Wt solenoid valve When 71 runoids are fully excited,
Air inside the cavity 14 is sucked through the gas venting device ft42'x. In this case, depending on the command from the timing regulating device (not shown), the suction of the gas venting device fjIL42 is longer than the suction of the plunger 20 by, for example, 0.2 seconds to 1.
The delay is set to be about seconds, preferably about 0.3 to 0.5 seconds. Further, the degree of vacuum is, for example, 200 to 300 Torr on the plunger 2 side.

The gas venting device 42@ is set at about 150 to 250 Torr, and this is the auxiliary vacuum tank 67? The setting is achieved through rigor. The auxiliary vacuum tank 67 is provided as close to the plunger 200 as possible, taking into account all the resistance that occurs in relatively thin piping sections and passages during nitrogen suction. Well done,
The pipe 35 having the seven lexiple hoses 35a is made as short as possible and has a relatively large pipe diameter, for example, 1 inch.

Furthermore, the air passage 11b provided in the fixed mold 11 is connected to a pipe 75 equipped with a filter T2, a 7-lexiple portion T3, and a solenoid valve 74''.
5 is connected to the piping 35 leading from the auxiliary vacuum tank 77 to the plunger 20 before the solenoid valve 700.

Furthermore, the other port of the solenoid valves 70, 71.74 is equipped with companion piping 81.82.83 for the solenoid valves 7B and 79.80'.
are connected to each other, and these pipes 81, 82 .
83 is provided with a variable throttle valve 84 and is joined to a pipe 85 described below and connected to, for example, an air compressor 86 in a factory. Then, the solenoid valves 7B and 79 are closed at 70°71.74'.
．． By opening 80, high pressure air is released into the plunger 20 and into the injection sleeve 22. The gas is sent to a degassing device 42 and used for spraying for internal cleaning.

A casting method using the die-casting machine configured as described above will be explained. The movable mold 12 is moved to the position shown in the figure, the mold is clamped, and the cylinder 44t of the degassing device [42]
Activate to move the spool 46 to the mold 11.12 as shown.
into the spool hole. At this time, the injection cylinder 18
Since the piston/cx head 19 and the injection sleeve 22 have been lowered, the injection cylinder 18 is tilted to inject the molten metal into the injection sleeve 22 whose plunger 20 has been lowered, and after raising it again, the injection sleeve 22 is lowered. 22t - Raise to engage locking sleeve 17 as shown. Then, after vacuuming, which will be described later, the injection cylinder 18
When the piston rod 19 is raised by supplying oil, the plunger 20 is raised and injection of molten metal, indicated by reference numeral 8T in FIG. 2, is started. At this time, cold water is supplied to the Granger 2a from the cold water supply 35, and this cold water is supplied to the pipe 29a.
After rising inside, it overflows into the space 23a and flows into the cold water passage 3.
6, the plunger tip 23 and plunger rod 24 are cooled.

Further, the injection sleeve 22 is also cooled from the outside by a cooling device not shown inside. Therefore, on the upper end surface of the plunger tip 23 and the inner wall surface of the injection sleeve 22 following this, a solidified layer is formed by the solidification of the molten metal, as shown by the reference numeral 9 in FIG. 2 and FIG. 8. Since the inside of the vacuum tank 60 and the auxiliary tank 6T have been previously depressurized by suction with the vacuum pump 62, when the solenoid valve TOk is first opened before injection starts, negative pressure is applied to the suction hole 34 of the plunger rod 24. However, the air in the annular groove 23b of the plunger tip 23 flows through the air passage 23c1 and the annular groove 26a.
1 filter 31, air passage 27b1, annular groove 27a, air passage 33, and air passage 32. Also, when the solenoid valve 74t is opened at the same time as the solenoid valve 70 is opened,
Air passage 11b communicating with annular grooves 11a and 12a
Negative pressure acts on the annular grooves 11a' and 12a, and the air inside the annular grooves 11a' and 12a is
Air passage 11b' (after k.

It gets sucked in. More this! p about 0.2 seconds to 1 second,
Preferably, when the solenoid valve 71 is opened with a delay of 0.3 seconds to 0.5 seconds, the gas in the cavity 14 is sucked through the exhaust hole 6 (lx) via the gas vent path 40, the gas vent groove 41, and the bypass 48. The gas inside the cavity 14 is exhausted.In this way, the gas inside the cavity 14 is suctioned from both the plunger 20 side and the gas venting device 42 side.
The vacuum level is the same between the inside, the injection sleeve 22, and the gap between the plunger tip 23, but the plunger 20 side tbf
Due to the rapid suction to n = and the vacuum level on the plunger 20 side being greater than the vacuum level on the gas venting device fi42 side, the solidified M9 forms on the end face of the plunger tip 23 and its surface as shown in FIG. It is strengthened by adhering to the surrounding annular recess, and is also cooled to 300 to 400°C as the plunger chip 23 cools! ll solidified layer 9
becomes thicker. This prevents outside air from entering through the gap between the injection sleeve 22 and the plunger tip 23. Further, the molten metal does not enter the cavity 14 before the molten metal is injected.

After creating a vacuum in the C cavity 14 in this way, the injection operation begins, and when the plunger tip 23t is advanced while performing seven degassing steps, the molten metal 87 in the injection sleeve 22 flows between the fixed sleeve 17 and the constriction 15. is injected into the cavity 14 through the plunger tip 23.
As the solidified layer 9 moves forward, it is pushed by the plunger tip 23 and rises, and the upper end of the solidified layer 9 reaches the plane 11c in front of the constriction part 15.

12c, but the annular groove 11a + 12a
Air is being sucked from both sleeves 17.
．． By providing the tapered part and the packing 17b at the joint part of the injection sleeve 22, outside air does not enter, and the cylindrical part of the coagulation layer 9 remains in close contact with the inner circumferential surface of the injection sleeve 22, and the plunger tip 23 At the same time, it rises and its tip abuts against the flat ff111c, 12c in front of the constricted portion 15. Then, as the plunger tip 23 rises further, the solidified layer 9 is crushed between the end face of the plunger tip 23 and the flat surfaces 11c and 12c of the mold 11°12, so the solidified layer 9 is broken, but the cavity 1
Even if the inside of the molten metal is evacuated from above, air will not enter from the injection sleeve portion as described above, so air will not enter the molten metal and the flow of the molten metal will not be disturbed. When the cavity 14 is filled with the molten metal 81, the molten metal 87 rises in the gas vent groove 41 and comes into contact with the lower surface of the valve body 56a together with the gas. At this time, the impact applied to the valve body 56a is
Since the mass of the molten metal 87 is extremely large compared to the mass of the gas and has a large inertia, the impact applied to the gas valve body 56a is greater than that of the valve body 56a, which is caused by the ball 57 to bounce off the compression coil 5.
8 while compressing the valve body 56a to the valve seat 49t-
Obstruction. Therefore, even if the molten metal 87 is completely blocked from flowing out from the valve seat 49 and mixes with the gas in the gas vent path 4o and gas vent #1141, becoming splashed and hitting the valve body 56aK discontinuously, the molten metal 87 is once pushed. Raised next valve body 56
Since a is pulled upward by the tension spring 52, the upper position is maintained and the exhaust passage is reliably closed by the valve body 56a.

The valve body 56a is cooled under pressure for a predetermined period of time with the valve body 56a closed, and then the movable metal member 12 is opened and the cylinder 44 of the gas venting device 142 is opened.
Then, raise the spool 46t to engage the movable metal W12, and take out the product from the cavity 14.

Note that when the spool 46 rises, only the spool 46 rises due to separation resistance between the valve body 56m and the solidified metal, and the valve stem 56 rises with a delay.
The ball 57, which has been disengaged from the force 1 of 56b, engages again with #56b, completing the preparation for the next casting. Furthermore, at the upper limit of the rise of the spool 46, the return rod 51 contacts the stopper 59 and pushes down the valve rod 56t, so that the valve body 56
a will open securely and preparations for the next casting will be made.

In this embodiment, the gas inside the metal pumping cavity 14 is transferred to both the gas venting device ft42 side and the plunger 20@.
Although an example has been shown in which suction is performed from the gas venting device 42 side, suction may be performed only from the gas venting device 42 side.

By the way, normal aluminum products are 40 to 60 c.
Contains gas of c/100gAL, but gas degassing device 4
When 2 is used, the pressure is 5 to 10 cc/100 PAt, and a high-quality product with a pressure resistance of 100 to 150 kp/cm 2 can be obtained. Generally, heat treatment is possible when the gas content is less than 5 cc/100 PAA, and 1 cc/100 PAA
When L is reached, welding is possible, but if the inside metal of the cavity 14 is evacuated and the injection spout portion is also evacuated, an injection product that can be heat treated and welded can be obtained.

In addition, this can be achieved not only by using new materials but also by using return materials.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, in a vertical injection device of a die-casting machine, a vacuum suction device sucks gas in a mold cavity while molten metal is supplied into an injection sleeve. At the same time, a space connected to a vacuum suction device is provided between the inserted injection sleeve and the injection hole, and a sealing portion is provided between the distal end surface of the injection sleeve and the contact surface of the injection hole. In addition to degassing the inside of the mold cavity, vacuum suction is applied from the injection sleeve to promote degassing and obtain a high-quality product. #Even if a solidified layer of hot water forms and is pushed up by the rise of the plunger, the air between the injection hole and the injection sleeve is sucked to the outside, and the outside air does not enter here, so it does not affect the cast product. There are no cavities or pinholes, the hook surface is also good, and the quality of the cast product is greatly improved.

[Brief explanation of drawings]

Figures 1 to 7 show an embodiment of the vertical injection device for a die-casting machine according to the present invention, Figure 1 is a schematic configuration diagram and pneumatic piping diagram, and Figure 2 is an enlarged sectional view of the injection sleeve and plunger. , FIG. 3 is a sectional view along line AA in FIG. 2, FIG. 4 is a sectional view along BB in FIG. 2, FIG.
The figure is a vertical sectional view of the mold degassing device, and Figure 7 is D of Figure 6.
D sectional view, FIG. 8 is a sectional view of an injection sleeve insertion portion of a conventional injection device. 11 - Fixed mold, 11a, 12a fist Φ... annular groove, 11b... air passage, 12 φ... movable Venus, 14... cavity, 16-... injection hole section ,
18... Fist injection cylinder, 22... Injection sleeve, 23b... Annular groove, 42... Mold degassing device, 62... Vacuum bonder, 66... Vacuum tank , 67...Auxiliary vacuum tank, 70.71...
...Solenoid valve, T4...Solenoid valve, 75...Piping,
87... Molten metal. Patent questioner: Ube Industries, Ltd.

Claims (1)

[Claims] In a vertical injection device of a die-casting machine, in which an injection sleeve on the injection cylinder side is inserted into and removed from an injection hole in the lower end of the mold, and the molten metal in the injection sleeve is injected into the mold cavity, the molten metal is in the injection sleeve. A vacuum suction device is provided for sucking and discharging the gas in the mold cavity in a supplied state, and a space connected to the vacuum suction device is formed between the inserted injection sleeve and the injection hole. A vertical injection device for a die-casting machine, characterized in that a seal portion is provided between the upper end surface of the inserted injection sleeve and the contact surface of the injection hole portion.