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WO-2026094793-A1 - PLUNGER, SEALING METHOD, AND SUPPLY DEVICE

WO2026094793A1WO 2026094793 A1WO2026094793 A1WO 2026094793A1WO-2026094793-A1

Abstract

The present invention provides a plunger to be used in a die casting apparatus, said plunger having sealing performance that meets a high vacuum requirement.　A plunger (50) according to the present invention comprises: a plunger tip (60) on the outer periphery of which a seal ring (66), a spacer ring (67A), and a backup ring (68) are mounted in order from the front (F); a plunger rod (80) connected to the rear (R) of the plunger tip (60); and a sealing medium supply path (65) for supplying a sealing medium toward at least one from among the seal ring (66), the spacer ring (67A), and the backup ring (68) through the plunger tip (60).

Inventors

  • ITO YASUNORI

Assignees

  • 株式会社久保製作所

Dates

Publication Date
20260507
Application Date
20251024
Priority Date
20241101

Claims (8)

  1. A plunger tip (60) has a seal ring (66), a spacer ring (67A), and a backup ring (68) arranged in order from the front (F) on its outer circumference, A plunger rod (80) is connected to the rear (R) of the plunger tip (60), A plunger (50) comprising a seal medium supply passage (65) that supplies a seal medium through the plunger tip (60) to at least one of the seal ring (66), spacer ring (67A), and backup ring (68).
  2. The aforementioned seal ring (66) is A first seal medium passage (66B) that is connected to the seal medium supply passage (65) and penetrates in the thickness direction, The plunger (50) according to claim 1, comprising: an annular seal medium storage groove (66A) that leads to the first seal medium passage (66B) and is recessed from the outer surface of the seal ring (66).
  3. The spacer ring (67A) is further equipped with a spacer ring retainer (67B) stacked on the outside of the spacer ring (67A), The spacer ring (67A) and the spacer ring retainer (67B) are It is provided with a second seal medium passage (67C) that is connected to the seal medium supply passage (65) and penetrates in the thickness direction, Each of the seal ring (66) and the backup ring (68) has a joint, The plunger (50) according to claim 1.
  4. The sealing medium supply passage (65) is The outer circumferential surface of the plunger tip (60) that opens toward the seal ring (66), The plunger (50) according to claim 1.
  5. The seal medium supply pipe (5) connected to the seal medium supply passage (65) is attached to the plunger rod (80). The plunger (50) according to claim 1.
  6. The plunger tip (60) is A cylindrical outer tip (61) having an internal containment gap, The outer tip (91) comprises an inner tip (71) disposed in the housing gap of the outer tip (91), The outer tip (91) is It comprises a chip head (92) and a chip body (96) that are separable in the direction of the central axis (C), The plunger (50) according to claim 1.
  7. A sealing method between a plunger sleeve (21) and a plunger (50) according to any one of claims 1 to 6, which is provided inside the plunger sleeve (21) so as to be reciprocally movable, A sealing method comprising supplying a sealing medium from the sealing medium supply passage (65).
  8. A supply device (130) for supplying a sealing medium to a sealing medium supply pipe (5) in a die-casting apparatus comprising a plunger sleeve (21) and a plunger (50) according to any one of claims 1 to 6, which is provided reciprocally movably inside the plunger sleeve (21), A tank (131) for storing the sealing medium, A pressure pump (133) that sucks in and discharges the sealing medium stored in the tank (131), A metering pump (135) discharges a predetermined amount of sealing medium from the pressure pump (133), A supply device (130) comprising: a medium supply pipe (137) through which the sealing medium flows to the sealing medium supply pipe (5) via the tank (131), the pressure pump (133), and the metering pump (135); and an on/off valve (139) provided in the medium supply pipe (137) between the pressure pump (133) and the metering pump (135), which opens and closes according to the pressure of the sealing medium inside the medium supply pipe (137).

Description

Plunger, sealing method, and feeding device This invention relates to a plunger tip used in die-casting apparatus. Die casting is a manufacturing method that involves melting metals, such as aluminum alloys, and pouring them into a mold cavity at high speed and pressure to produce cast products. In die-casting equipment, the plunger, which constitutes the injection mechanism, experiences wear on the sliding surface because the outer surface of the plunger tip slides against the inner surface of the sleeve. In more severe cases, galling may occur, so it is common practice to apply a lubricant to the sliding surface to ensure smooth movement. For example, the die-cast plunger disclosed in Patent Document 1 has a structure in which a plunger tip and a plunger rod are connected by a joint interposed between them, and two flow channels are provided to supply air and lubricant separately in the axial direction of the plunger rod. At the outlet ends of the two flow channels connected to the joint, the air and lubricant are mixed to form a mist, and this mist is distributed via a distribution channel to multiple individual flow channels provided in the joint. The mist is then sprayed from nozzles opening toward the outer circumference of each individual flow channel toward the inner surface of the plunger sleeve, thereby applying lubricant to the inner surface of the plunger sleeve. In die casting, vacuum die casting, which involves exhausting the air from the cavity before pouring the molten metal to rapidly inject the molten metal into the cavity of the mold, has been applied primarily to products with high quality requirements. In this vacuum die casting process, ensuring the sealing performance between the plunger sleeve and the plunger is essential. This is a side view showing the schematic configuration of a die-casting apparatus.This is a longitudinal cross-sectional view showing the configuration of a plunger according to the first embodiment.Figure 2 is a magnified view of the plunger tip and its vicinity.This figure shows the procedure for attaching various rings to the plunger tip according to the embodiment, and the function of the rings.This is a side cross-sectional view showing the main part of the plunger according to the second embodiment.This is a plan view showing the main parts of the plunger according to the second embodiment.This is a side cross-sectional view showing the main part of the plunger according to the third embodiment.This is a side cross-sectional view showing the main part of the plunger according to the fourth embodiment.This diagram shows the schematic configuration of the device used for evaluating seal performance.This graph shows the results of the seal performance evaluation.This graph shows the results of the seal performance evaluation.This figure shows a preferred configuration of a supply device for supplying a high-viscosity substance, such as grease, to a sealing medium supply pipe. Next, an embodiment of the plunger applied to a die-casting apparatus will be described in detail, with reference to the drawings as appropriate. In each figure, common parts are denoted by the same reference numerals, and redundant explanations are omitted. Furthermore, the following description will proceed in the following order: an example of the configuration of the die-casting apparatus 1 to which the plunger 50 according to this embodiment is applied, the configuration of the plunger 50, and a casting experiment (example) conducted using the plunger 50. [Configuration of die-casting apparatus 1: See Figure 1] The die-casting apparatus 1 comprises a mold section 10 that forms a casting cavity CA from which molten metal is injected, an injection section 20 for injecting molten metal into the casting cavity CA of the mold section 10, and a vacuum suction section 30 for evacuating the casting cavity CA prior to the injection of molten metal. Although not shown in the figures, the die-casting apparatus 1 also includes a ladle for supplying molten metal to the injection section 20. In the die-casting apparatus 1, the front (F) and rear (R) are defined as shown in Figure 1 and other figures. The mold section 10 comprises a fixed mold 12 whose position is fixed, and a movable mold 13 that reciprocates relative to the fixed mold 12. In the mold section 10, when the movable mold 13 is abutted against the fixed mold 12 in a closed state, a casting cavity CA is formed between the fixed mold 12 and the movable mold 13. The mold section 10 includes a device for clamping the fixed mold 12 and the movable mold 13 (not shown in the figure). In this closed state, a molten metal flow path is formed between the fixed mold 12 and the movable mold 13, consisting of a gate 14 opening into the casting cavity CA and a runner 15 connecting the gate 14 to the plunger sleeve 21 of the injection section 20, which is coupled to the back of the fixed mold 12. The movable mold 13 contains an ejector 11 for demoldi