JP2563032Y2 - Die casting machine injection equipment - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection device for a die casting machine.

[0002]

2. Description of the Related Art FIGS. 3 and 4 show the shape of a conventional plunger tip slidably provided in an injection sleeve and the state of heat flow inside the plunger tip in an injection device of a vertical die casting machine. It is a schematic diagram.
In the conventional plunger tip shape, the tip of the plunger tip 34a is completely flat as shown in FIG. 3, or the tip of the plunger tip 34a shown in FIG. A low frustoconical projection 34c of about 10 mm is fixed to the stepped portion 34.
It has an integral shape having b (plunger tip shoulder). In this case, in both FIG. 3 and FIG.
5, the upper end surface 55a is located below the horizontal surface of the tip of the plunger tip 34a or the horizontal position of the stepped portion 34b.

[0003]

The plunger tip 34a of the conventional injection device 31 has the following problems.
That is, while the injection sleeve 35 receives the molten metal 44 such as Al or Mg from the ladle and docks to the mold side, and loads the molten metal 44 in the injection sleeve 35 into the cavity 17 formed between the dies, Heat transfer occurs from the side of the molten metal 44 to the side of the plunger tip 34a as shown by arrows in FIGS. The temperature of the plunger tip 34 a rises due to the heat received from the molten metal 44 and expands. The expansion causes the plunger tip 3 to move up and down in the injection sleeve 35.
The sliding of the plunger tip 34a becomes difficult, and in order to prevent the plunger tip 34a from galling or abrasion, it is necessary to increase the clearance of the sliding portion between the injection sleeve 35 and the plunger tip 34a.

The gap between the injection sleeve 35 and the plunger tip 34a is determined on the assumption that the temperature of the plunger tip 34a rises sufficiently and expands. That is, in the initial stage of casting, the gap of the sliding portion between the injection sleeve 35 and the plunger tip 34a is large, and the molten metal 44 in the injection sleeve 35 passes through the gap and passes through the plunger 3.
There was a case where a so-called backflush was pushed back to the fourth side.

[0005]

According to the present invention, in order to solve such a problem, an injection device of a die casting machine is provided slidably in an injection sleeve, and
At the tip of the plunger tip having a cooling medium chamber therein, there is provided a truncated-cone-shaped projection having a flat surface whose tip surface is smaller in diameter than the outer diameter of the plunger tip. The cooling medium chamber was provided with a plunger tip provided so as to be located on the same surface as the wall surface on the front end side or behind the wall surface.

[0006]

The projection sleeve at the tip of the plunger tip is high and the rising position of the frusto-conical projection is located at the same level as or at the rear of the upper end surface of the internal cooling medium chamber of the plunger tip. Since the temperature rise of the sliding portion between the two is small and the thermal expansion is small, the gap between the two can be reduced. Further, since the molten metal filled in the space around the projections is rapidly solidified, the sealing effect of the molten metal by the solidified layer is large. Back flushing is prevented by the synergistic effect of the small gap between the plunger tip and the injection sleeve and the sealing between the plunger tip and the injection sleeve by the solidified layer.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail with reference to the embodiments shown in the drawings. FIG. 1 illustrates one embodiment of an injection molding apparatus to which the present invention is applied, and is exemplified as a horizontal clamping vertical casting type injection molding apparatus. FIG. 2 is an enlarged sectional view of a main part of an injection device having a plunger tip.

In FIG. 1, reference numeral 10 denotes a fixed plate, on which a fixed die 13 is fixed via keys 11 and 12. Between the fixed platen 10 and an end platen (not shown), four tie bars 14 are laid in a rectangular arrangement, and a movable platen 15 is slidably fitted to the tie bar 14. A movable die 16 is fixed to the movable platen 15. The movable mold 16 and the fixed mold 13
The cavity 17 is formed on the abutting surface of.

A runner 19 communicating with the cavity 17 is formed on the abutting surface 18 of the mold, and fixed sleeves 20 and 21 which are halved at the lower end of the runner 19.
Are fixed, but they abut each other during mold clamping,
Form a cylindrical stationary sleeve.

The movable mold 16 is provided with a key 2 with respect to the movable platen 15.
2, a product extruding device 23 is provided in a space in a movable mold 16 formed between the movable plate 15 and the movable plate 15. The fixed platen 10 is fixed on a machine base 24, and the movable platen 15 is slidably mounted on the machine base 24.

The movement of the movable platen 15 and the application of the mold clamping force
It is provided by a rod 25 and a toggle link mechanism 26 of a mold clamping cylinder not shown. On the other hand, machine base 2
A pit 27 is formed below the floor 4 on the floor side, and a vertical casting unit 28 is provided in the pit 27.

Regarding the details of the vertical casting unit 28,
This will be described below. The vertical casting unit 28 has a frame 30 connected and fixed to the machine base side via a rod 29. A vertical injection device 31 is rotatably supported on the frame 30 in the middle thereof. In the injection device 31,
On the upper side, an elongated frame 32 that can move up and down is provided.
An injection cylinder 33 is provided below the frame 32, and a plunger 34 is connected to a tip of a piston rod of the injection cylinder 33. Plunger 3
The plunger tip 34a is attached to the tip of the fourth.

The frame 32 is vertically movable with respect to the injection cylinder 33 by a hydraulic device (not shown). An injection sleeve 35 is attached to the upper end of the frame 32. Also, on the left side of the frame 30,
A tilting cylinder 37 is rotatably mounted on the middle of a tilting cylinder 37 via a shaft 38 via a bracket 36. The tip of the piston rod of the cylinder 37 is rotatably connected to the lower part of the frame of the injection device 31 via a bracket 39.

On the other hand, one end of an arm 40 is fixed to one end of a support shaft which supports the injection device 31 (not shown) so as to be swingable with respect to the frame 30, and is in contact with the free end side of the arm 40. In a position where the limit is applied, a limit switch 41a for detecting a tilt limit and a limit switch 41b for detecting a vertical state are fixed to the side surface of the frame 30.
In the illustrated state, the limit switch 41b is in contact with the arm 40 and is ON.

On the other hand, reference numeral 42 denotes a ladle for discharging and supplying the molten metal 44 from the bottom, and reference numeral 42a denotes a valve rod which can be moved up and down when the injection device 31 is rotated to the tilt limit as shown by a chain line in FIG. , The molten metal 44 is supplied into the injection sleeve 35. In addition,
Reference numeral 43 denotes a nozzle for spraying a gas on the upper surface of the injection sleeve 35 for cleaning or removing an oxide film formed on the upper surface of the molten metal 44 in the injection sleeve 35 by gas blowing.

Here, the structure of the plunger tip 34a according to the embodiment of the present invention will be described in detail with reference to FIG.
In FIG. 2, 45 is a water pipe, 46 is a sleeve cooling jacket, 47 is a spacer, 48 is a sleeve coupling,
32 is a frame, 50 is a chip joint, and 55 is an internal cooling medium chamber.

An internal cooling medium chamber 55 is provided inside the plunger tip 34a, and a water pipe 45 is provided vertically in the center of the plunger 34. Water as a cooling medium is supplied through the water pipe 45 to the inside. Cooling water that has passed through the cooling medium chamber 55 and has been provided with a gap between the inner peripheral surface of the tip joint 50 and the outer peripheral surface of the water pipe 45 that are arranged concentrically with the water pipe 45 and has passed through the internal cooling medium chamber 55. Is to be discharged.

The plunger tip 34a has a frusto-conical projection 34c formed on a cylindrical plunger tip 34e.
Is slightly smaller than the outer diameter of the plunger tip portion 34e, and the difference between the two diameters, that is, the outer peripheral upper surface of the plunger tip portion 34e forms a plunger tip shoulder portion 34b having a stepped portion. 34d is a plane portion. Further, the position of the upper end face 55a of the internal cooling medium chamber 55 and the horizontal position of the plunger tip shoulder 34b are set to the same level, or the horizontal position of the plunger tip shoulder 34b is set to be lower than the position of the upper end wall 55a of the internal cooling medium chamber 55. It is located below.

On the other hand, since the distance between the plunger tip shoulder 34b and the internal cooling medium chamber 55 is considerably shorter than that of the conventional plunger tip 34a, heat transfer from the molten metal 44 to the internal cooling medium chamber 55 is performed. The molten metal 44 in this portion solidifies quickly, and exhibits a sealing effect of preventing the molten metal 44 from flowing into the gap between the injection sleeve 35 and the plunger tip 34a.

Further, as shown in FIG. 2, the retained heat of the molten metal 44 in the vicinity of the plunger tip shoulder 34b is transferred in the direction of the internal cooling medium chamber 55, so that the injection sleeve 35, the plunger tip 34a and The heat transfer near the sliding part is small, and the temperature rise is small. Therefore, since the thermal expansion of the plunger tip 34a toward the injection sleeve 35 is small, the plunger tip 34a and the injection sleeve 35
The gap between them can be made small, and combined with the sealing effect of the solidified layer generated at the plunger tip shoulder portion 34b, backflushing is unlikely to occur. In some cases, the frusto-conical projection 34c can be immediately raised without providing the plunger tip shoulder 34b.

Next, the operation of the embodiment constructed as described above will be described. At a timing before and after the fixed mold 13 and the movable mold 16 are matched, the tilting cylinder 37 is actuated, the piston rod is retracted, and the injection device 31 is moved into the mold as shown by a chain line in FIG. Is tilted away from the lower side and faces the ladle 42.

At this time, as shown in FIG.
The plunger tip 34a at the tip of the nozzle 4 is lowered, and in this state, a predetermined amount of molten metal 44 is released from the ladle 42 by opening the valve stem 42a in the ladle 42.
5. When the supply of the molten metal 44 is completed, the cylinder 37 is operated, and its piston rod is extended, so that the injection device 3
1 rotates so as to be in a vertical state as a whole.

At this time, since gas is ejected from the nozzle 43, even if molten metal adheres near the opening at the upper end of the injection sleeve 35, the adhered matter is blown off by the ejected gas and cleaning is performed. . Immediately after this cleaning operation is completed, the injection sleeve 35 is raised together with the plunger 34, the docked fixed sleeves 20, 21 and the injection sleeve 35 are docked, the plunger 34 and the plunger tip 34a are raised, and the molten metal 44 is discharged. It is injected into the cavity 17.

Plunger 34 and plunger tip 3
When the molten metal 44 is pressurized and filled into the cavity 17 with the rise of 4a, the release material sprayed inside the injection sleeve 35 before the hot water supply is crushed and can no longer serve as a heat insulating material.
Heat transfer from the molten metal 44 to the plunger tip 34a increases. In particular, heat transfer from the plunger tip shoulder 34b to the internal cooling medium chamber 55 is remarkable, so that a thin solidified layer of the molten metal 44 is formed on the plunger tip shoulder 34b.
When the injection is completed in this state, the injection sleeve 35 and the plunger 34 are lowered, the mold is opened, and the product is taken out.

In the above embodiment, an example of the vertical casting type injection device is shown. However, the present invention is applied to a horizontal casting type injection device in which the injection sleeve 35 and the plunger tip 34a are in a horizontal state. Can also be applied.

[0026]

As is clear from the above description, in the present invention, the injection device of the die casting machine is provided with a plunger slidably provided in an injection sleeve and having a cooling medium chamber therein. At the tip of the tip, a truncated cone-shaped projection having a tip surface formed with a flat surface having a diameter smaller than the outer diameter of the plunger tip is provided. The structure with the plunger tip provided so as to be located on the same surface or on the rear side of this wall surface reduces the temperature rise in the sliding part between the plunger tip and the injection sleeve. And a thin solidified layer is formed around the frusto-conical projection, so that the molten metal is prevented from flowing into the gap between the plunger tip and the injection sleeve. The click flash completely prevented.

[Brief description of the drawings]

FIG. 1 is a schematic front view (partially sectional view) illustrating one embodiment of an injection molding apparatus to which the present invention is applied.

FIG. 2 is a longitudinal sectional view showing one embodiment of a plunger tip portion of the injection device according to the present invention.

FIG. 3 is a longitudinal sectional view showing an example of a plunger tip portion of a conventional injection device similar to the present invention.

FIG. 4 is a longitudinal sectional view showing another example of the plunger tip portion of the conventional injection device similar to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Fixed board 13 Fixed mold 16 Movable mold 17 Cavity 28 Vertical casting unit 31 Injection device 32 Frame 33 Injection cylinder 34 Plunger 34a Plunger tip 34b Plunger tip step (shoulder) 34c Truncated conical projection 34d Plunger tip surface part 34e Plunger tip part 35 Injection sleeve 44 Melt 45 Water pipe 46 Sleeve cooling jacket 47 Spacer 48 Sleeve coupling 50 Tip joint 55 Internal cooling medium chamber 55a Upper end face of internal cooling medium chamber

Claims (1)

(57) [Scope of request for utility model registration] 1. An injection sleeve which is slidably provided in an injection sleeve.
At the tip of the plunger tip having a cooling medium chamber therein, there is provided a truncated cone-shaped projection having a flat surface whose tip surface is smaller in diameter than the outer diameter of the plunger tip. An injection device for a die casting machine, comprising a plunger chip provided so as to be positioned on the same surface as a wall surface on the front end side of the cooling medium chamber or behind the wall surface.