WO2020008770A1 - Die casting machine injection device and casting method - Google Patents

Abstract

Inflow of outside air into a suctioned sleeve is prevented, problems with molten metal are suppressed, and stable suction within the sleeve is realized. The injection device 1 of a die casting machine 100 is configured to permit suction of a suction recess 120, which is partitioned by a tip 20 of a plunger 12, and a space 75 ahead of the front end of the tip 20. The inside of a sleeve 11 can be suctioned through penetrating portions 14, 15 that each penetrate the sleeve 11 from inside to outside at a prescribed first location C1 of the sleeve 11 in the advancing/retreating direction D1 of the plunger 12 and at a second location C2 set apart rearward from the first location C1. The opening area of the penetrating portion 15 at the first location C1 is greater than the opening area of the penetrating portion 14 at the second location C2. (Selected Drawing: FIG. 5)

Description

Injection device and casting method for die casting machine

The present invention relates to an injection device that injects a molten metal toward a cavity of a die casting machine by a plunger that can advance and retreat inside a sleeve, and a casting method using the injection device.

In order to efficiently increase the degree of vacuum in the sleeve into which the molten metal is supplied or in the cavity into which the molten metal is injected by the plunger from within the sleeve, and to suppress the occurrence of entrapment nests in die-cast products, there is known a technique for suctioning the inside of the sleeve. I have.
For example, Patent Document 1 describes a die casting machine that suctions the inside of a sleeve using a vacuum pump.
Such a die casting machine includes first to fourth suction devices for suctioning the inside of the sleeve and the cavity of the mold. A first suction device and a second suction device are used for suction inside the sleeve. The first suction device sucks the inside of the sleeve through a hole located near the pouring port into which the molten metal such as an aluminum alloy is injected and ahead of the pouring port. The second suction device sucks a closed space formed between a constricted portion between the tip of the plunger and the flange of the plunger rod and the inner peripheral surface of the sleeve, thereby forming a constricted portion of the tip and an inner peripheral portion of the sleeve. The inside of the sleeve is sucked through a gap between the sleeve and the surface. The suction of the closed space formed by the constriction is performed through a through hole formed in the flange of the plunger rod along the axial direction.

In Patent Literature 1, after the molten metal is injected into the sleeve, when the plunger advances to a position where the pouring port is closed by the tip of the plunger, first, the first suction device removes the chip in the sleeve through the hole near the pouring port. Also sucks the gas in the space in front. At this time, the gas in the cavity is also sucked through the front space in the sleeve.
Next, when the plunger advances to a position where the hole near the pouring port is closed by the tip, the operation shifts to suction by the second suction device. The second suction device suctions the closed space defined between the constricted portion of the plunger and the inner peripheral surface of the sleeve through the axial through hole of the flange of the plunger rod, so that the front of the tip in the sleeve is suctioned. Aspirate space.
After the suction by the second suction device is started, the suction in the cavity is started by the third suction device.
According to the description of Patent Document 1, the inside of the cavity is sucked through the sleeve by the first suction device, so that the degree of vacuum in the cavity is prevented from becoming higher than the degree of vacuum in the sleeve. Is suppressed.

JP 2014-117741 A

If the molten metal in the sleeve becomes violent due to outside air flowing into the sleeve, which becomes a negative pressure with respect to the atmospheric pressure due to the suction, the suction hole may be closed due to the adhesion of the molten metal, or the molten metal component ( In some cases, the deposition of molten metal scum may cause a decrease in suction efficiency.
`` Molten metal rampage '' means that, for example, when the outside air blows in front of the chip from the rear end of the sleeve through the radial gap between the plunger and the sleeve, the molten metal foams and scatters, or the molten metal surface shakes violently. To tell. It is desirable to stably suck the gas in the sleeve without blocking the suction path or reducing the suction efficiency due to the runaway of the molten metal.
Also in the die casting machine described in Patent Document 1, there is a risk that holes for suction and pipes may be blocked due to the molten metal being violent during suction in the sleeve.

From the above, it is an object of the present invention to realize stable suction in a sleeve by preventing inflow of outside air into a drawn sleeve and suppressing runaway of a molten metal.

The present invention is an injection device that includes a sleeve into which molten metal is supplied, and a plunger that can advance and retreat inside the sleeve, and injects the molten metal toward a cavity of a die casting machine by the plunger. Is retracted radially inward with respect to the inner peripheral portion of the sleeve, and a suction concave portion continuous in the circumferential direction is defined, so that a space ahead of the front end of the chip and the inside of the suction concave portion can be suctioned. The inside of the sleeve is sucked through the penetrating portions which penetrate the sleeve at the first predetermined position of the sleeve in the retreating direction of the plunger and at the second position separated rearward from the first position. It is possible, and the opening area of the penetration portion at the first location is larger than the opening area of the penetration portion at the second location.
“Inside of the suction concave portion” means a space defined between the tip and the sleeve.

In the injection device for a die-casting machine of the present invention, it is preferable that the first penetrating portion is used for suctioning a space in front, and the second penetrating portion is used for suction inside the suction recess.

Further, the present invention is a casting method using an injection device that injects molten metal toward a cavity of a die casting machine by a plunger that can advance and retreat inside a sleeve to which the molten metal is supplied, and a tip of the plunger includes: The suction concave portion is retracted radially inward with respect to the inner peripheral portion of the sleeve, and is defined by a suction concave portion that is continuous in the circumferential direction. At two places, the inside of the sleeve can be sucked through the penetrating portions penetrating the sleeve both inside and outside, and the opening area of the penetrating part at the first point is smaller than the opening area of the penetrating part at the second point. And communicating with the inside of the suction recess while reducing the pressure in the front space by suction through the first penetrating portion communicating with the space in front of the front end of the chip. It characterized thereby depressurized by sucking the inside of the suction recess via the through portion of the second positions that.

ADVANTAGE OF THE INVENTION According to the injection apparatus of the die-casting machine of this invention, and the casting method using the same, as described later, by preventing the outside air from flowing into the sucked sleeve and suppressing the runaway of the molten metal, the stability in the sleeve is improved. Suction can be realized.

FIG. 2 is a side view in which a part of the die casting machine according to the embodiment of the present invention is broken. FIG. 2 is a diagram schematically showing a system for sucking the inside of a sleeve of an injection device provided in the die casting machine shown in FIG. 1. 6 is a flowchart illustrating an example of a sleeve vacuum process. FIG. 2A is a partially cutaway side view illustrating a main part of the injection device of the die casting machine illustrated in FIG. 1. (B) is a sectional view of the injection device at the position IVb in (a). It is a schematic diagram which shows an example of the penetration part formed in the 1st location and the 2nd location of a sleeve, respectively. (A)-(c) is a figure which shows a series of steps of sleeve vacuum suction by the die casting machine shown in FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
(Schematic configuration of die casting machine)
FIG. 1 is a schematic side view (partially including a cross-sectional view) of a die casting machine 100 including an injection device 1 according to an embodiment of the present invention.
The die casting machine 100 is directed to a movable plate 4 on which a movable mold 22 is installed, a fixed plate 5 on which a fixed mold 21 is installed, a machine base 8 supporting the movable plate 4 and the fixed plate 5, and a cavity 23. An injection device 1 for injecting molten metal 18 and a control device 3 for controlling the operation of each part of the die casting machine 100 are provided.

The die casting machine 100 evacuates the cavity 23 and the inside of the sleeve 11 of the injection device 1 in order to suppress the occurrence of a cast cavities (entrance cavities) due to the entrainment of gas into the molten metal 18.

Four tie bars 7 are inserted into the insertion holes of the movable platen 4 and the fixed platen 5. The movable platen 4 moves along the tie bar 7 with respect to the fixed platen 5 so as to be able to advance and retreat. When the fixed mold 21 and the movable mold 22 are engaged as shown in FIG. 1, a cavity (product part) 23 is formed therebetween. A casting 18 is manufactured by injecting and filling a cavity 18 with a molten metal 18 such as aluminum or an aluminum alloy.
The movable platen 4 includes an extrusion plate 41 to which an extrusion pin 42 is attached.

The injection device 1 is provided on the fixed platen 5. The injection device 1 includes a sleeve 11 into which the molten metal 18 is supplied, and a plunger 12 that can advance and retreat with respect to the sleeve 11 inside the sleeve 11. The injection device 1 injects the molten metal 18 toward the cavity 23 by the plunger 12.
The front end of the sleeve 11 penetrates through the fixed platen 5 and fits into the hole 10 provided in the fixed mold 21. The rear end side of the sleeve 11 projects outside the fixed platen 5 and extends rearward in the horizontal direction. A pouring port 13 into which the molten metal 18 is injected is provided at a rear end side of the sleeve 11.
A hot water storage chamber is formed including the inside of the sleeve 11 and the hole 10 of the fixed mold 21. This hot water storage chamber communicates with the cavity 23 via the runner 24 and the gate 25.

Regarding the injection device 1, the front in the moving direction of the plunger 12 when injecting the molten metal 18, that is, the side closer to the cavity 23 is defined as “front”, and the side farther from the cavity 23 is defined as “rear”. .

The plunger 12 generally includes a plunger rod 19 and a plunger tip 20 provided on the front side of the plunger rod 19.
When the molten metal 18 is injected, the plunger 12 moves forward, and after the injection, moves backward. The direction in which the plunger 12 moves forward and backward (front-back direction) is defined as the moving direction D1.

The control device 3 controls the driving of the hydraulic cylinder that moves the plunger 12 forward and backward while detecting the position of the plunger 12 in the forward and backward direction D1 with a sensor or the like.
The detection of the position of the plunger 12 is performed, for example, by detecting a mark provided on the piston rod corresponding to the stroke of the hydraulic cylinder with a non-contact sensor.

As shown in FIG. 2, the injection device 1 is provided with a vacuum suction system 2 that suctions the inside of the sleeve 11. The vacuum suction system 2 reduces the pressure inside the sleeve 11 by suction using a vacuum pump 37 and a vacuum tank 36.
In the sleeve 11 of the present embodiment, two through portions (suction ports) 14 and 15 penetrating through the inside and outside of the sleeve 11 are provided so that the gas inside the sleeve 11 can be sucked by the vacuum suction system 2. The sleeves 11 are arranged side by side in the axial direction (D1). These penetrating parts 14 and 15 are formed on the upper part of the sleeve 11 so as to be located above the surface of the molten metal 18 supplied inside the sleeve 11.

The penetrating portion 15 penetrates the peripheral wall of the sleeve 11 in the thickness direction at a predetermined first location C1 (FIG. 4A) of the sleeve 11 in the reciprocating direction D1.
The penetrating portion 14 penetrates the peripheral wall of the sleeve 11 in the thickness direction at a second location C2 (FIG. 4A) remote from the first location C1.

The vacuum suction system 2 depressurizes the inside of the sleeve 11 to a predetermined degree of vacuum by evacuating the gas in the sleeve 11 through the penetrating portions 14 and 15. When the inside of the sleeve 11 is depressurized by the vacuum suction system 2, the cavity 23 is also sucked through the inside of the sleeve 11. Therefore, the vacuum suction system 2 can depressurize the inside of the sleeve 11 and the cavity 23.

The die casting machine 100 typically includes another vacuum suction system (not shown) for directly reducing the pressure of the cavity 23 through a suction path provided in a mold.
Such a vacuum suction system is, for example, air from the cavity 23 through one or more connection ports 28 provided in a chill vent 27 (Chill-Vent) provided at the boundary between the fixed mold 21 and the movable mold 22. Is directly sucked. The sucked gas may include, in addition to air, molten metal or vapor of a mold release agent.

The control device 3 (FIG. 1) opens and closes various valves provided in the vacuum suction system of the die casting machine 100 including the vacuum suction system 2 at an appropriate timing, thereby suctioning the inside of the sleeve 11 and the cavity 23 by each system. The state can be controlled.

(Vacuum suction system)
An example of the configuration of the vacuum suction system 2 that can suction the inside of the sleeve 11 will be described with reference to FIG. The vacuum suction system 2 includes a vacuum pump 37, a vacuum tank 36, a merging / distribution unit 34, and a suction path 51 individually corresponding to the through portions 14 and 15 of the sleeve 11.
Each suction path 51 includes a vacuum filter 31 for evacuation, a pressure gauge for detecting the pressure in the suction path 51, a compound meter, and a pressure gauge from upstream to downstream of the flow of the gas sucked from the sleeve 11. In this order, a pressure detecting unit 32 such as a sensor and a selection valve 33 for selectively communicating the penetrating portions 14 and 15 with the vacuum tank 36 are provided.

開 閉 By opening and closing the selection valve 33, each of the penetrating portions 14 and 15 can be communicated with the vacuum tank 36 in a timely manner. Further, one or both of the penetrating portions 14 and 15 can be communicated with the vacuum tank 36 according to the filling rate of the molten metal into the sleeve 11 and the like.

The pressure inside the vacuum tank 36 is reduced by evacuation performed by operating the vacuum pump 37. When the vacuum tank 36 is used, the gas in the sleeve 11 can be sucked into the vacuum tank 36 in a timely manner by the pressure difference from the vacuum tank 36 while the vacuum pump 37 is continuously operated.
It is preferable that the penetrating portions 14 and 15 are selectively communicated with the vacuum tank 36 according to the position of the plunger 12 in the reciprocating direction D1, the state of suction from the penetrating portions 14 and 15, and the like. The selection valves 33 corresponding to the penetrating portions 14 and 15 are controlled so as to be opened and closed according to the pressure in the suction path 51 detected by the pressure detecting portion 32, the position of the plunger 12 in the reciprocating direction D1, and the like. be able to.

When vacuuming is performed by the vacuum suction system 2, the pressure difference between the inside of the vacuum tank 36 and the inside of the sleeve 11 is passed through the through portion of the through portions 14 and 15 in which the corresponding selection valve 33 is open. The gas inside the sleeve 11 flows into the suction path 51. The gas flowing into the suction path 51 passes through the vacuum filter 31, the pressure detection unit 32, and the selection valve 33, and joins with the flow from the other suction path 51 in the junction / distribution unit 34, and further, the vacuum / air blow switching valve 35 and the piping. Through 55, it flows into the vacuum tank 36.

時 に は At the time of vacuum suction, it is preferable to monitor the pressure (degree of vacuum) of the suction path 51 detected by the pressure detection unit 32 to confirm that the evacuation is performed normally. For example, if a part of the penetrating portion or the suction path 51 is closed due to the molten metal scum, or if the opening is narrowed by the accumulation of the molten metal, or the vacuum filter 31 is clogged, even if it is not closed. , The pressure detected by the pressure detector 32 deviates from the normal range to the higher side. In this case, cleaning of the penetrating portion or the suction path 51 where the abnormality has occurred, cleaning or replacement of the vacuum filter 31 and the like may be performed.

(Air blow)
The penetrating portions 14, 15 and the suction paths 51 of the penetrating portions 14, 15 can also be used as paths for performing an air blow for ejecting pressurized air to the inside of the sleeve 11. By air blow, molten metal scum can be removed from the suction path 51 and the penetrating portions 14 and 15.
A pressurized air supply system 9 (FIG. 2) for performing air blow includes a compressed air source 39 which is a supply source of pressurized air, and a pressurized tank 38 which stores pressure therein by being supplied with air by the compressed air source 39. It has.
The vacuum suction system 2 and the pressurized air supply system 9 of this embodiment are configured to include a vacuum / air blow switching valve 35 installed downstream (downstream at the time of vacuum suction) from the merging / distribution unit 34. The vacuum / air blow switching valve 35 switches between the vacuum suction and the air blow by switching the connection destination of the merging / distribution section 34 to the vacuum pipe 55 and the air blow pipe 56.
The suction path 51 upstream of the merging / distributing section 34 (upstream at the time of vacuum suction) is common for vacuum evacuation and air blow. Therefore, the air blow and the evacuation can be continuously performed without interrupting the production of the cast product due to the replacement of the pipes to the through portions 14 and 15.

It is preferable that the pressure detection unit 32 can detect the pressure at the time of air blow in addition to the pressure at the time of evacuation.
When a part of the selection valves 33 is closed, the flow rate of the air in the penetrating portion and the suction path 51 corresponding to the opened selection valve 33 increases, so that the cleaning effect is enhanced.

The air blow through the penetrating portions 14 and 15 may be performed in a state in which the molten metal 18 is not stored in the sleeve 11 so as not to be shortly before the hot water is supplied so that the molten metal 18 will not be disturbed by the air blow or hinder the hot water supply. it can.

ス リ ー ブ The process of vacuuming the sleeve by the circuit A (control circuit) from step S104 to step S114 shown in FIG. 3 shows the basic operation of the selection valve 33 corresponding to the through portions 14 and 15, respectively.

Here, at the start of the sleeve vacuum, it is assumed that all the penetrating portions 14 and 15 are open. After the start of the sleeve vacuum, the penetrating portions 14 and 15 are sequentially closed by the tip 20 of the plunger 12 advanced. As the plunger 12 advances, the tip 20 sequentially passes through the penetrating portions 14 and 15. After the penetrating portion is closed by the second large-diameter portion 202 of the tip 20, the penetrating portion is in a state of not communicating with the front space 75 or the inside of the suction concave portion 120. It cannot be used for a sleeve vacuum sucked from the inside of the recess 120. Although such a penetrating portion does not communicate with the inside of the front space 75 and the inside of the suction concave portion 120, the suction efficiency is maintained by suppressing the pressure increase in the vacuum tank 36, and molten metal scum enters the penetrating portion. In order to avoid this, it is preferable to close the corresponding selection valve 33 after the use is disabled.
Therefore, as described below, as the plunger 12 advances, when the plunger 12 reaches a position closed by the second large diameter portion 202 of the plunger tip 20 for each of the penetrating portions 14 and 15 as the plunger 12 advances. The selection valves 33 corresponding to the sections are sequentially closed.
That is, as the plunger 12 advances, the selection valves 33 corresponding to the through portions 14 and 15 are sequentially closed.

In step S101 shown in FIG. 3, it is confirmed that the inside of the vacuum tank 36 has reached a sufficient degree of vacuum, and a preparation completion signal is output.
In step S102, after pouring, after the plunger 12 moves forward and exceeds the position at which the pouring port 13 is closed, the operation of pulling the sleeve 11 to a vacuum by the vacuum suction system 2 is started. A predetermined position of the plunger 12 in the advance / retreat direction D1 can be determined as a vacuum start position at which vacuum suction is started. The arrival of the plunger 12 at the set vacuum start position is detected by detecting the stroke of a hydraulic cylinder that drives the plunger 12 with a non-contact sensor or the like. The arrival of the plunger 12 at each set position in the following steps is detected in the same manner.

In step S103, the vacuum / air blow switching valve 35 is switched to vacuum suction.
In step S104, the plunger 12 reaches the set position (FIG. 2 / rear penetrating part closing position) for closing the penetrating part 14 (suction port).
In step S105, the selection valve 33 corresponding to the through portion 14 is closed.

In step S106, the plunger 12 reaches a set position (FIG. 2 / front penetrating part closing position) for closing the penetrating part 15. Here, immediately before the plunger 12 reaches the set position for closing the penetrating part 15, the degree of vacuum of the suction path 51 corresponding to the penetrating part 15 is measured using the pressure detecting part 32.
In step S107, the selection valve 33 corresponding to the through portion 15 is closed.
In step S108, the vacuum / air blow switching valve 35 is turned off (neutral position).
In step S109, the selection valves 33 of the respective penetrating portions 14 and 15 are all opened.
In step S110, the vacuum / air blow switching valve 35 is switched to air blow.
In step S111, the air is blown into the sleeve 11 through the penetrating portions 14 and 15 by using the pressurized tank 38 by the pressurized air supply system 9 having a part of piping common to the vacuum suction system 2. Perform air blow. At this time, the selection valves 33 of the through portions 14 and 15 may be all open, or the selection valves 33 may be opened one by one in order. After the air blow is completed, the vacuum / air blow switching valve 35 is turned off (neutral position) (S114).
In step S112, while the air blow is being performed, the pressure in the suction passages 51 of the penetrating sections 14 and 15 is measured by the pressure detecting section 32, and based on the pressure, whether or not the pipe or the vacuum filter 31 is clogged. Is determined. If clogging occurs, an alarm is issued by a lamp, a buzzer, or the like (step S113).

The selection valve 33 is preferably closed while the corresponding penetration is closed by the second large diameter portion 202 of the tip 20. When the second large diameter portion 202 passes through the penetrating portion and the penetrating portion communicates with the space 88 around the plunger rod 19 in FIG. May flow from the space 88 into the vacuum tank 36 via the suction portion 51 via the through portion. Since this is not intended, for example, in the step shown in FIG. 6C, it is preferable to close the selection valve 33 corresponding to the penetrating portion 14 closed by the tip 20.

The operation of the selection valve 33 described above is only an example. It is preferable that the selection valve 33 be appropriately closed based on not only the disabled state due to the closing of the through portions 14 and 15 but also the disabled state of the suction path 51 and the like caused by the molten metal scum as described above. Alternatively, it is possible to open and close the selection valves 33 respectively corresponding to the penetrating portions 14 and 15 based on manufacturing conditions according to a mold and a product.

(Suppression of outside air inflow by suction of suction recess of plunger tip)
The inside of the sleeve 11 sucked by the vacuum suction system 2 (FIG. 2) has a negative pressure with respect to the atmospheric pressure. Therefore, based on the pressure difference between the outside air that is the atmosphere outside the sleeve 11 and the gas inside the sleeve 11, the outside air in the space 88 (FIG. 4A) around the plunger rod 19 at the rear end of the sleeve 11 is If the molten metal 18 in the sleeve 11 flows into the space 75 in which the molten metal 18 is stored through the gap between the plunger tip 20 and the sleeve 11, the molten metal 18 foams and scatters, and the molten metal surface vibrates violently. If the molten metal 18 is exposed in this manner, the amount of molten metal derived from the molten metal 18 in the sleeve 11 increases accordingly. Further, when the molten metal 18 is violent, gas is likely to be entrained in the molten metal 18.

In the present embodiment, by preventing outside air from flowing into the space 75 (FIG. 4A) in which the molten metal 18 in the sucked sleeve 11 is stored and suppressing the runaway of the molten metal 18, the molten metal 18 is caused by molten metal scum. The inside of the sleeve 11 is stably sucked while avoiding clogging of the penetrating portions 14 and 15 and the suction path 51 and lowering of suction efficiency.
Since the entrapment of gas into the molten metal 18 is suppressed by suppressing the runaway of the molten metal 18, the occurrence of entrapment nests is prevented.

In this embodiment, in order to suppress the outside air from flowing into the front space 75 in the sleeve 11, both the front space 75 and the inside of the suction recess 120 of the plunger tip 20 are formed by using the through portions 14 and 15. Is evacuated.

As shown in FIG. 4A, the plunger tip 20 has a larger diameter than the plunger rod 19, and pushes out the molten metal 18 stored in the sleeve 11 toward the front when the plunger 12 advances.
The plunger rod 19 is fastened to the plunger tip 20 by a tip joint 20D.

The plunger tip 20 has a first large-diameter portion 201 located on the front side in the advance / retreat direction D <b> 1 and a second large-diameter portion located on the rear side in the advance / retreat direction D <b> 1 and partitions the suction concave portion 120 between the first large-diameter portion 201. A large-diameter portion 202. The diameter of the plunger tip 20 at the position of the suction recess 120 is smaller than the diameters of the first large diameter portion 201 and the second large diameter portion 202. Therefore, a section between the first large diameter portion 201 and the second large diameter portion 202 in the axial direction (D1) of the plunger tip 20 is referred to as a small diameter portion 203. An outer peripheral portion 203A of the small-diameter portion 203 is formed with a two-sided width 203B (FIG. 4B) that engages with a fastening tool.

As shown in FIGS. 4A and 4B, the suction concave portion 120 is retracted inward in the radial direction D2 with respect to the inner peripheral portion 11A of the sleeve 11, and is continuous in the circumferential direction D3.
The suction recess 120 is continuous over the entire circumference of the plunger tip 20. Therefore, a gap having an annular cross section is formed between the inner peripheral portion 11A of the sleeve 11 and the outer peripheral portion 203A of the small-diameter portion 203 corresponding to the suction concave portion 120.

In the present embodiment, when the plunger 12 advances with respect to the sleeve 11, vacuum is applied to both the space 75 (on the cavity 23 side) before the front end 20 </ b> A and the inside of the suction recess 120 behind the space 75. By suction by the suction system 2, both the space 75 and the inside of the suction recess 120 are depressurized to the atmospheric pressure.

According to the suction between the front space 75 and the inside of the suction recess 120, the space in the sleeve 11 behind the front space 75 and having the same pressure as the front space 75 (the inside of the suction recess 120). To prevent the outside air outside the sleeve 11 from flowing into the front space 75 in the sleeve 11. This is because there is no difference between the pressure P1 inside the suction recess 120 and the pressure P2 in the space 75, or even if there is a pressure difference, the pressure difference (P1-P2) is equal to the atmospheric pressure P0 and the pressure in the front space 75. This is because the difference from P2 (P0−P2) is sufficiently small, so that outside air is prevented from flowing into the front space 75 through the inside of the suction recess 120.

When the plunger 12 moves forward, if both the front space 75 and the inside of the suction recess 120 are continuously sucked, the inflow of outside air into the front space 75 that stores the molten metal 18 is suppressed during the suction. can do. During the suction of the front space 75, it is preferable that the inside of the suction concave portion 120 be sucked without interruption so that the inflow of outside air into the front space 75 is always suppressed while the front space 75 is sucked.

In the present embodiment, based on the configuration of the above-described vacuum suction system 2 (FIG. 2), the suction inside the front space 75 and the suction recess 120 can be performed by one vacuum suction system 2. Both the gas sucked from the front space 75 and the gas sucked from inside the suction recess 120 are sucked by the same vacuum pump 37 via the same vacuum tank 36.
Therefore, as compared with a case where a vacuum suction system is separately provided in the front space 75 and the suction concave portion 120, the device cost of the vacuum pump 37, the vacuum tank 36, and the like can be reduced. Also, since the number of vacuum suction systems is small, the number of inspection points for gas leakage (leakage) is small, so that the inspection work efficiency is good.

However, it is also permitted that the front space 75 and the inside of the suction recess 120 are sucked through separate systems.

In order to suppress the inflow of outside air into the front space 75, the inside of the suction recess 120 is suctioned, and the outer periphery 20C of the plunger tip 20 (FIG. 4B) and the inner periphery 11A of the sleeve 11 are combined. It is effective to seal the gap between them with an appropriate sealing member, a tip lubricant or the like.

(Structure and effect of penetration part)
By the way, the injection device 1 of the present embodiment can suction the inside of the sleeve 11 at the first portion C1 and the second portion C2 of the sleeve 11 in the advance / retreat direction D1 through the penetrating portions 14 and 15 respectively penetrating the sleeve 11. The main feature is that the opening area of the through portion 15 at the first location C1 is larger than the opening area of the through portion 14 at the second location C2.

When the length in the advance / retreat direction D1 is short as in the sleeve 11 shown in FIG. 4, the openings related to the suction efficiency of the front space 75 are provided by arranging the penetrating portions in many places of the sleeve 11 at intervals in the advance / retreat direction D1. It may be difficult to secure a sufficient area. Even in this case, by providing a through portion having a large opening area at any one place, the opening area can be sufficiently increased for vacuum suction in the sleeve 11 and thus vacuum suction of the cavity 23 communicating with the inside of the sleeve 11. Can be secured.

Hereinafter, the through portion 15 at the first location C1 is referred to as a front through portion 15, and the through portion 14 at the second location C2 is referred to as a rear through portion 14.
The front penetration portion 15 is used for suctioning a space 75 in front of the front end 20 </ b> A of the chip 20. The rear through portion 14 is used for suction inside the suction recess 120.

FIG. 5 is a plan view showing an example of the form of the front penetration part 15 and the rear penetration part 14. As shown by a solid line or a two-dot chain line in FIG. 5, the front penetrating portion 15 may have an appropriate form as long as the opening area is larger than that of the rear penetrating portion 14.

前方 The front penetration part 15 shown by a solid line in FIG. 5 is a hole having a circular opening. The same applies to the rear penetration portion 14 shown in FIG. Since the opening diameter of the front penetrating part 15 is larger than the opening diameter of the rear penetrating part 14, the opening area A1 of the front penetrating part 15 is larger than the opening area A2 of the rear penetrating part 14. .

The front penetrating portion 15 shown by a two-dot chain line in FIG. 5 is formed in an oval shape longer in the circumferential direction D3 of the sleeve 11 than the rear penetrating portion 14 shown in FIG. The opening area A1 of the front penetration part 15 is also larger than the opening area A2 of the rear penetration part 14.
In addition, the front penetrating portion 15 may have an oval shape that is longer than the rear penetrating portion 14 in the axial direction of the sleeve 11 (the reciprocating direction D1).

The front penetration part 15 and the rear penetration part 14 are not limited to the form of a circle or an ellipse, but may be an appropriate form such as an ellipse or a rectangle in consideration of connection with the suction pipe.

Each of the front penetrating part 15 and the rear penetrating part 14 does not necessarily need to be constituted by only one hole. As long as a predetermined opening area can be given to each of the front penetration part 15 and the rear penetration part 14, the front penetration part 15 and the rear penetration part 14 can each be comprised from one or more arbitrary numbers of holes.
For example, for the rear penetrating portion 14 formed of one circular hole, the front penetrating portion 15 can be configured by two or more circular holes having the same diameter as the hole of the rear penetrating portion 14. In this case, a set of two or more holes corresponds to the front penetrating portion 15, and the front penetrating portion 15 can have an opening area twice or more the opening area of the rear penetrating portion 14.
If the total opening area of the one or more holes constituting the front penetration part 15 is larger than the total opening area of the one or more holes constituting the rear penetration part 14, the front penetration part 15 and the rear penetration part Each can be provided with an appropriate number of holes.

(4) The plurality of holes constituting the front through portion 15 can be appropriately arranged regardless of whether they are regular or irregular. For example, a plurality of holes constituting the front through portion 15 may be arranged in the circumferential direction D3 of the sleeve 11. In this case, a plurality of holes may be arranged over a predetermined angle range on both sides of the 12 o'clock position, which is the upper end of the sleeve 11, so that each hole is located above the surface of the molten metal 18.

With the vacuum suction system 2 (FIG. 2), the front space 75 is sucked through the front penetrating portion 15, and when the inside of the suction concave portion 120 is sucked through the rear penetrating portion 14, the suction is performed through the front penetrating portion 15 having a larger opening area. It is possible to efficiently reduce the pressure of the front space 75 to a lower pressure than the inside of the suction recess 120.
Then, suction of the outside air into the front space 75 is suppressed by suction inside the suction recess 120 through the rear penetration portion 14, thereby preventing the molten metal 18 from rampaging, and thereby the penetration portions 14, 15 and the suction path caused by the molten metal scum. The pressure in the front space 75 can be reduced to a desired degree of vacuum while avoiding the blockage of 51 and a decrease in suction efficiency, thereby suppressing the occurrence of a nest.

According to the present embodiment, conventionally, in the sleeve vacuum suction in which the suction holes and the paths tend to be quickly closed due to the molten metal scum, it is necessary to avoid the blockage of the suction paths and the reduction of the suction efficiency. Stable suction in the inside can be realized. Therefore, it is not necessary to perform vacuum suction while suppressing the degree of vacuum and the filling rate of the molten metal in the sleeve in order to avoid blockage of the passage and the like, so that it is possible to realize vacuum suction of the sleeve with a high degree of vacuum and a high filling rate.

(Sleeve vacuum suction process)
With reference to FIGS. 6A to 6C, an example of a process of vacuum suction of the sleeve performed while suctioning the front space 75 and the inside of the suction recess 120 using the two through portions 14 and 15 will be described. I do.
In the present embodiment, when the plunger 12 moves forward with respect to the sleeve 11, the front penetrating portion 15 of the first location C1 and the rear penetrating portion 14 of the second location C2 are used to make the front end (cavity) of the front end 20A. The suction is continuously performed from the space 75 (on the 23 side) and the inside of the suction recess 120 behind the space 75.

In order to secure a sufficient suction time and increase the inside of the front space 75 and the inside of the suction concave portion 120 to a sufficient degree of vacuum, as shown in FIG. 13, it is preferable to start the sleeve vacuum suction when the inside of the suction recess 120 and the rear through portion 14 of the second location C2 communicate with each other.
However, in the present embodiment, both the front space 75 and the inside of the suction concave portion 120 may be vacuum-suctioned while the advance of the plunger 12 is temporarily stopped.

In order to suppress the outside air outside the sleeve 11 from flowing into the front space 75 through the inside of the suction recess 120, the vacuum suction inside the suction recess 120 is performed prior to the start of the vacuum suction of the front space 75. It is preferable to start.

In the state shown in FIG. 6A, both the front space 75 and the inside of the suction recess 120 are partitioned by the tip 20 into the sleeve 11 so as not to communicate with the pouring port 13. The front space 75 communicates with the front penetration portion 15, and the inside of the suction recess 120 communicates with the rear penetration portion 14.
Therefore, as shown by the solid arrow in FIG. 6A, the vacuum can be sucked from the front space 75 by the vacuum suction system 2 (FIG. 2) through the front penetration portion 15, and the broken line arrow in FIG. As shown in the drawing, suction can be performed from the inside of the suction recess 120 by the vacuum suction system 2 through the rear penetration portion 14.

Thereafter, the front space 75 and the suction recess 120 are closed until the front through-hole 15 is closed by the first large-diameter portion 201 of the tip 20 of the plunger 12 that has advanced, as shown in FIG. Vacuum suction from both the inside and the inside can be continued.

As shown in FIG. 6B, even after the front penetrating portion 15 is closed by the first large-diameter portion 201, the gap 89 between the first large-diameter portion 201 and the sleeve 11 (FIG. 6C). While sucking the front space 75 from the front through portion 15, the inside of the suction concave portion 120 can also be sucked from the rear through portion 14 through the gap 90. Even after the suction from the front space 75 is completed, the suction from the inside of the suction recess 120 can suppress the inflow of outside air into the front space 75 continuously.

In the present embodiment, suction penetration portions respectively corresponding to the front space 75 and the inside of the suction concave portion 120 are provided at two positions of the first position C1 and the second position C2 of the sleeve 11 in the advance / retreat direction D1. I have. Therefore, at least until immediately before the front penetrating part 15 is closed, as shown by a broken arrow in FIG. 6B, the suction concave part 120 is directly communicated with the inside of the suction concave part 120 through the rear penetrating part 14. What is necessary is to be able to suck continuously from inside.

As shown in FIG. 6B, if the front penetration portion 15 is closed by the first large diameter portion 201, at least the vacuum suction performed through the front penetration portion 15 directly communicating with the front space 75 ends. I do. In the state shown in FIG. 6B or 6C, the inside of the suction concave portion 120 does not necessarily need to communicate with the front through portion 15.

As described above, according to the present embodiment, through the front penetrating portion 15 communicating with the front space 75, until immediately before finishing the direct vacuum suction of the front space 75, through the rear penetrating portion 14 communicating with the inside of the suction recess 120. Direct vacuum suction inside the suction recess 120 can be continued.

However, the interruption of the vacuum suction is permissible as long as the time is short enough not to affect the occurrence of a entanglement due to the runaway of the molten metal 18 or the blockage of the penetrating portion or the like by the molten metal scum.
In other words, as long as the sleeve vacuum suction is stably established by suppressing the outside air inflow, at least one of the front space 75 and the inside of the suction recess 120 is partly provided from the start to the end of the sleeve vacuum suction. May be interrupted, or the start and end timings of the sleeve vacuum suction between the front space 75 and the inside of the suction recess 120 may be different.

If the dimension (Lp0) of the suction recess 120 in the advance / retreat direction D1 is smaller than the dimension (Ls3) in the advance / retreat direction D1 of the interval between the penetrating portions 14, 15, the first large-diameter portion is omitted. When the front penetrating part 15 is closed by 201 and the rear penetrating part 14 is closed by the second large diameter part 202, there is no penetrating part communicating with the inside of the concave part 120 for suction. May be interrupted. At this time, even if the molten metal 18 is unraveled, since there is no open through portion other than the penetrating portions 14 and 15, there is no fear that the penetrating portion is closed at least by scattering of the molten metal 18.

以外 In addition to the above, the configuration described in the above embodiment can be selected or changed to another configuration as appropriate without departing from the gist of the present invention.

A Circuit A1, A2 Opening area C1 First location C2 Second location D1 Retracting direction D2 Radial direction D3 Circumferential direction P0 Atmospheric pressure P1, P2 Pressure 1 Injection device 2 Vacuum suction system 3 Control device 4 Movable platen 5 Fixed platen 7 Tie bar 8 Machine base 9 Pressurized air supply system 10 Hole 11 Sleeve 11A Inner circumference 12 Plunger 13 Pouring port 14 Rear penetration (second penetration)
15 Forward penetration (first penetration)
18 Melt 19 Plunger rod 20 Plunger tip 20A Front end 20C Outer peripheral part 20D Tip joint 21 Fixed mold 22 Movable mold 23 Cavity 24 Runner 25 Gate 27 Chil vent 28 Connection port 31 Vacuum filter 32 Pressure detection unit 33 Selection valve 34 Merging / distribution unit 35 Vacuum / air blow switching valve 36 Vacuum tank 37 Vacuum pump 38 Pressurized tank 39 Compressed air source 41 Extruded plate 42 Extruded pin 51 Suction path 55, 56 Pipe 75 Front space 88 Space 89, 90 Gap 100 Die casting machine 120 Suction recess 201 First large-diameter portion 202 Second large-diameter portion 203 Small-diameter portion 203A Outer peripheral portion 203B Two-plane width

Claims (3)

1. An injection device that includes a sleeve to which molten metal is supplied inside, and a plunger that can advance and retreat inside the sleeve, and injects the molten metal toward a cavity of a die casting machine by the plunger,
   The tip of the plunger is retracted radially inward with respect to the inner peripheral portion of the sleeve, and a suction concave portion continuous in the circumferential direction is defined,
   A space in front of the front end of the tip and the inside of the suction recess are configured to be able to be sucked,
   At a predetermined first position of the sleeve in the reciprocating direction of the plunger, and at a second position separated rearward from the first position, the inside of the sleeve is inserted through the sleeve through the inside and outside of the sleeve, respectively. Can be aspirated,
   An opening area of the through portion at the first location is larger than an opening area of the through portion at the second location;
   An injection device for a die casting machine.
2. The first portion of the through portion is used for suction of the front space,
   The through portion at the second location is used for suction inside the suction recess.
   An injection device for a die casting machine according to claim 1.
3. A casting method using an injection device that injects the molten metal toward a cavity of a die casting machine by a plunger that can advance and retreat inside a sleeve in which the molten metal is supplied inside,
   The tip of the plunger is retracted radially inward with respect to the inner peripheral portion of the sleeve, and a suction concave portion continuous in the circumferential direction is defined,
   At a predetermined first location of the sleeve in the retreating direction of the plunger and at a second location behind the first location, the inside of the sleeve is passed through the sleeve through the inside and outside of the sleeve, respectively. Can be aspirated,
   The opening area of the penetration portion at the first location is larger than the opening area of the penetration portion at the second location,
   Through the penetrating portion of the second portion communicating with the inside of the suction concave portion, while reducing the pressure of the front space by suction through the penetrating portion of the first portion communicating with the space forward of the front end of the chip. The inside of the suction concave portion is depressurized by suction,
   A casting method, characterized in that:
   
   

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