JP2007229751A - Apparatus and method for lubricating plunger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus and a method for lubricating a plunger with which lubricant can surely be spread over the whole periphery on sliding surfaces of an injection sleeve and a plunger tip, in a simple constitution. <P>SOLUTION: In the apparatus for lubricating the sliding surfaces 10, 20 of the injection sleeve 1 for pouring molten metal from a molten metal supplying hole 1a and the plunger tip 2 for injecting the molten metal into a cavity in a forming mold by inserting so as to be slidable in this injection sleeve 1, this apparatus is provided with a lubricant holding member 4 for holding the lubricant, disposed so as to face to the rear end between the sliding surfaces 10, 20 of the injection sleeve 1 and the plunger tip 2; and a pressure reducing means 5 for drawing the lubricant held in the lubricant holding member 4 into the sliding surfaces 10, 20 of the injection sleeve 1 and the plunger tip 2 by reducing the pressure in the injection sleeve 1. In the pressure reducing means 5, a covering member 50 for plugging the molten metal supplying hole 1a, is included for closing the inner part of the injection sleeve 1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a plunger lubrication device and a plunger lubrication method, and more specifically, an injection sleeve in which a molten metal is poured from a hot water inlet, and a molten metal that is slidably fitted in the injection sleeve and is inserted into a cavity of a mold. The present invention relates to a plunger lubrication apparatus and a plunger lubrication method that lubricate a sliding surface with a plunger tip that injects water.

  In the plunger of the die-casting machine, the plunger tip is slidably fitted in the injection sleeve. With the plunger tip retracted, the molten metal is poured from the hot water inlet of the injection sleeve, and the plunger tip is driven forward. Then, the molten metal in the injection sleeve is injected and filled into the cavity of the mold. In order to properly inject the molten metal in the injection sleeve and slide the plunger tip with respect to the injection sleeve, it is necessary to properly lubricate the sliding surfaces of the injection sleeve and the plunger tip.

  As a conventional technique for lubricating the sliding surface between the injection sleeve and the plunger tip, Patent Document 1 is known. Patent Document 1 discloses an injection sleeve in which a molten metal is injected from a pouring port, a plunger chip that press-fits the molten metal in the injection sleeve into a mold cavity, and a lubricant on the inner surface of the injection sleeve through the pouring port. An injection sleeve lubrication device for a die casting machine including a lubricant injection device for injecting, wherein a suction passage communicating the inside and outside of the injection sleeve behind the pouring port is formed in the injection sleeve, and the suction passage An injection sleeve lubrication device for a die casting machine is disclosed, which includes a suction device for decompressing the inside of the injection sleeve via a pipe.

  Patent Document 1 discloses that an injection sleeve into which a molten metal is injected from a pouring port, a plunger chip that press-fits the molten metal in the injection sleeve into a cavity of a mold, and an inner surface of the injection sleeve through the pouring port are lubricated. An injection sleeve lubrication method for a die casting machine provided with a lubricant injection device for injecting an agent, the disposing step of disposing the plunger tip in an injection sleeve behind a pouring port of the injection sleeve, and the disposing step Is completed, and the lubricant injection device injects the lubricant onto the inner surface of the injection sleeve through the pouring port of the injection sleeve and the lubricant injection step at the same time or the lubrication. During the agent injection process or after the arrangement process is completed, the suction device communicates the inside and the outside of the injection sleeve behind the pouring port by the suction device. The suction step of reducing the pressure in the injection sleeve from the clearance between the inner peripheral surface of the injection sleeve and the outer peripheral surface of the plunger tip via the suction passage formed in the injection sleeve, and the lubricant injection step are completed. There is disclosed a method of lubricating an injection sleeve of a die casting machine, comprising a step and a step of ending the suction step.

JP 2004-291058 A

  However, in the conventional technique such as the above-mentioned Patent Document 1, if the lubricant does not spread over the entire circumference between the injection sleeve and the plunger tip and is not blocked, the gap between the inside of the injection sleeve and the suction passage Therefore, the lubricant injected into the injection sleeve is not attracted toward the portion between the inner peripheral surface of the injection sleeve and the outer peripheral surface of the plunger tip by the pressure reducing action of the suction device. There was a problem that the lubricant was not sufficiently applied to the sliding portion between the inner peripheral surface of the plunger and the outer peripheral surface of the plunger tip. As a result, the forward speed of the plunger tip varies, and the molten metal cannot be stably injected, and the sliding surface between the injection sleeve and the plunger tip is likely to be galling. Furthermore, when the lubricant is spray-applied in the injection sleeve, the lubricant is mixed into the molten metal supplied to the injection sleeve, which makes it difficult to improve the quality of the die-cast product.

  The present invention has been made in view of the above-described problems, and with a simple configuration, a lubrication device for a plunger and a lubrication device for the plunger that can reliably distribute the lubricant over the entire circumference of the sliding surface of the injection sleeve and the plunger tip. It aims to provide a method.

In order to achieve the above object, the plunger lubrication device according to claim 1 has an injection sleeve into which molten metal is poured from a hot water inlet, and is slidably fitted into the injection sleeve so as to be slidably inserted into the cavity of the mold. Plunger lubrication device for lubricating a sliding surface with a plunger tip for injecting molten metal, and holding a lubricant disposed so as to face the rear end of the sliding surface of the injection sleeve and the plunger tip And a pressure reducing means for sealing the inside of the injection sleeve and reducing the pressure to draw the lubricant held by the lubricant holding member into the sliding surface of the injection sleeve and the plunger tip. It is.
In order to achieve the above object, the plunger lubrication method according to claim 2 is an injection sleeve into which a molten metal is poured from a hot water inlet, and is slidably inserted into the injection sleeve to be inserted into the mold cavity. A method of lubricating a plunger that lubricates a sliding surface with a plunger tip that injects a lubricant, wherein a lubricant holding member impregnated with a lubricant is disposed so as to face the rear end of the sliding surface of the injection sleeve and the plunger tip. Then, the injection sleeve is sealed, the inside thereof is decompressed, and the lubricant impregnated in the lubricant holding member is drawn into the sliding surface of the injection sleeve and the plunger tip.

In the first aspect of the invention, the lubricant holding member is disposed so as to face the rear end of the sliding surface of the injection sleeve and the plunger tip when the plunger tip is positioned in the retreat limit in the injection sleeve. The lubricant is held by the lubricant holding member. When the hot water supply port is closed with a lid member to seal the inside of the injection sleeve and the pressure inside the injection sleeve is reduced by the pressure reducing means, the lubricant held by the lubricant holding member is placed on the sliding surface of the injection sleeve and the plunger tip. It is reliably pulled in and evenly distributed throughout and lubricated.
In the invention of claim 2, the lubricant holding member impregnated with the lubricant faces the rear end of the sliding surface of the injection sleeve and the plunger tip when the plunger tip is positioned in the retreat limit in the injection sleeve. It arrange | positions as follows. Then, the hot water supply port is closed with a lid member, the inside of the injection sleeve is sealed, and the inside thereof is decompressed, so that the lubricant impregnated in the lubricant holding member is reliably drawn into the sliding surface of the injection sleeve and the plunger tip. Lubricate evenly.

According to the first aspect of the present invention, the lubricant holding member that holds the lubricant disposed so as to face the rear end of the sliding surface of the injection sleeve and the plunger tip, and the inside of the injection sleeve are sealed and depressurized. And a pressure reducing means for drawing the lubricant held by the lubricant holding member into the sliding surface of the injection sleeve and the plunger tip, and the lubricant on the sliding surface of the injection sleeve and the plunger tip. It is possible to provide a plunger lubrication device that can be reliably distributed over the entire circumference.
According to the second aspect of the present invention, the lubricant holding member impregnated with the lubricant is disposed so as to face the rear end of the sliding surface of the injection sleeve and the plunger tip, the injection sleeve is sealed, and the inside is depressurized. Then, the lubricant impregnated in the lubricant holding member is drawn into the sliding surface of the injection sleeve and the plunger tip, so that the lubricant can be reliably put on the sliding surface of the injection sleeve and the plunger tip. It is possible to provide a method of lubricating the plunger that can be distributed over a wide area.

First, an embodiment of the plunger lubricating device of the present invention will be described in detail based on FIG. 1 and FIG. In the drawings, the same reference numerals are given to similar or corresponding parts.
The plunger lubrication device according to the present invention generally has an injection sleeve 1 into which molten metal is poured from a hot water supply port 1a, and is slidably inserted into the injection sleeve 1 to inject molten metal into a cavity 3a of a mold 3. A lubricant that lubricates the sliding surfaces 10 and 20 with the plunger tip 2 and that faces the rear end between the sliding surfaces 10 and 20 of the injection sleeve 1 and the plunger tip 2. The lubricant holding member 4 to be held and the pressure inside the injection sleeve 1 are reduced and the pressure is reduced to draw the lubricant held on the lubricant holding member 4 into the sliding surfaces 10 and 20 of the injection sleeve 1 and the plunger tip 2. And means 5. The decompression means 5 includes a lid member 50 that closes the hot water supply port 1 a in order to seal the inside of the injection sleeve 1.

  As shown in FIG. 1, the die casting apparatus includes a mold 3 and a mold clamping device that opens and closes the mold 3, and the mold 3 includes a fixed mold 31 attached to a fixed platen 30, and And a movable mold 33 attached to a movable platen 32 which is inserted through the tie bar 34 and is provided so as to be close to and away from the fixed platen 30. As the die casting apparatus, for example, an apparatus having a clamping force of about 1650 tons is used. By closing the movable mold 33 with respect to the fixed mold 31, a cavity 3 a having a predetermined shape is formed on the abutting surfaces of the both 31 and 33.

  The tip of the injection sleeve 1 (the right end in FIG. 1) reaches a runner that passes through the fixed platen 30 and the fixed mold 31 and communicates with the cavity 3a. On the upper surface behind the injection sleeve 1, there is provided a pouring port 1 a for pouring the molten metal drawn from the holding furnace with a ladle. An injection cylinder 6 that is actuated by hydraulic pressure or the like is disposed coaxially with the injection sleeve 1 behind the injection sleeve 1 (left side in FIG. 1). It is connected to a plunger tip 2 fitted into the sleeve 1. A predetermined clearance is formed between the inner peripheral surface of the injection sleeve 1 and the outer peripheral surface of the plunger tip 2. In the embodiment shown in FIG. 2, the retreat limit of the plunger tip 2 by the injection cylinder 6 is set so that the plunger tip 2 slightly protrudes from the rear end of the injection sleeve 1.

  As shown in FIG. 2, a lid member 50 is provided at the pouring port 1a of the injection sleeve 1 so as to be opened and closed. When the pouring port 1a is closed by the lid member 50, the inside of the injection sleeve 1 is sealed. A lubricant holding member 4 is provided at the rear end of the injection sleeve 1. The lubricant holding member 4 is made of a material that can be infiltrated with a lubricant such as sponge or cloth, and is formed in an annular shape, and its inner diameter is slightly from the rear end of the injection sleeve 1 at the retreat limit position. Is set to a size that allows the plunger tip 2 to be inserted. For the lubricant holding member 4, for example, as indicated by an arrow in FIG. 2, a lubricant dropping device for dropping the lubricant continuously or intermittently can be provided, and the lubricant is stored. A lubricant tank may be provided immediately below, and a part of the lubricant holding member 4 may be impregnated with the lubricant and sucked up. Further, a cover may be provided on the outer periphery of the lubricant holding member 4 for the purpose of preventing the evaporation of the lubricant and preventing the adhesion of dust. For example, an aqueous graphite-based lubricant can be used as the lubricant.

  The decompression means 5 for decompressing the inside of the injection sleeve 1 comprises a vacuum pump 51 and a pipe line 52 connecting the vacuum pump and the inside of the injection sleeve. The pipe line 52 is indicated by an arrow in FIG. As shown, the cover member 50 that opens and closes the hot water supply port is provided so as to pass through and open into the interior thereof. By setting it as such a structure, the decompression means 5 containing the cover member 50 can be provided, without adding the process to the conventional injection sleeve 1. FIG. However, the decompression means of the present invention may connect the pipe line 52 of the vacuum pump 51 directly to the injection sleeve 1 or may connect to the mold 3 of the die casting machine. That is, the decompression means 5 of the present invention only needs to be able to decompress the inside of the injection sleeve 1 in a state where the hot water supply port 1a is closed and sealed by the lid member 10. A vacuum pump 51 that can reduce the pressure in the injection cylinder 1 to about 300 Torr, for example, is used.

Next, the lubrication method for the plunger of the present invention will be described in detail along with the operation depending on the case of using the apparatus configured as described above.
The plunger lubrication method of the present invention generally includes an injection sleeve 1 into which molten metal is poured from a hot water supply port 1 a, and a slidably fitted insert in the injection sleeve 1 to fill the molten metal into the cavity 3 a of the mold 3. It lubricates the sliding surfaces 10 and 20 with the plunger tip 2 to be injected, and the lubricant holding member 4 impregnated with the lubricant is disposed at the rear end between the injection sleeve 1 and the sliding surfaces 10 and 20 of the plunger tip 2. The injection sleeve 1 is sealed and the inside thereof is decompressed, and the lubricant held by the lubricant holding member 4 is drawn into the sliding surfaces 10 and 20 of the injection sleeve 1 and the plunger tip 2. Is.

  When the injection of the molten metal supplied into the injection sleeve 1 is completed, the plunger chip 2 is retracted slightly from the rear end of the injection sleeve 1 by driving the injection cylinder 6 and enters the inside of the lubricant holding member 4. . At the rear end between the inner peripheral surface of the injection sleeve 1 and the outer peripheral surface of the plunger tip 2 (sliding surfaces 10, 20), the lubricant holding member 4 holding the lubricant is located over the entire circumference. Will be doing. In this state, the hot water supply port 1 a of the injection sleeve 1 is closed by the lid member 50, the movable die 33 is closed with respect to the fixed die 31, the injection sleeve 1 is sealed, and the injection sleeve 1 is driven by the vacuum pump 51. When the inside is depressurized, the lubricant held by the lubricant holding member 4 moves forward between the inner peripheral surface (sliding surface 10) of the injection sleeve 1 and the outer peripheral surface (sliding surface 20) of the plunger tip 2. Is reliably pulled in toward the sliding surface and spreads evenly over the entire sliding surfaces 10 and 20. Then, when the inside of the injection sleeve 1 is released to the atmospheric pressure, the lid member 50 is opened, the molten metal is poured into the injection sleeve 1 from the pouring port 1a, and the plunger tip 2 is advanced by driving the injection cylinder 6 to slide. The outer peripheral surface of the plunger tip 2 slides stably with respect to the inner peripheral surface of the injection sleeve 1 by the lubricant that is evenly drawn into the surfaces 10 and 20 over the entire periphery.

  Here, in accordance with the present invention, the lubricant is drawn into the sliding surfaces 10 and 20 of the injection sleeve 1 and the plunger chip 2 from the rear, and the lubricant is sprayed into the injection sleeve 1 as in the conventional technique. The forward drive speed of the plunger tip 2 at the time of injection is compared with the case. When the forward drive speed of the plunger tip 2 at the time of injection is set to 3.3 m / s, the conventional spray coating has a variation of 2.9 to 3.7 m / s. In the case of retraction, the variation in the forward speed of the plunger tip 2 was reduced to 3.2 to 3.5 m / s, and stable injection could be performed.

  Further, in the present invention, the lubricant is drawn in from the rear to the front of the sliding surface of the injection sleeve 1 and the plunger tip 2 without spraying the lubricant into the injection sleeve 1 as in the prior art. Since the lubricant is not mixed into the molten metal supplied to the injection sleeve 1, the quality of the die-cast product is improved, and the amount of lubricant used can be reduced.

It is the fragmentary sectional view which showed one Embodiment of the die-casting apparatus with which the plunger lubrication apparatus of this invention is applied. It is sectional drawing which expanded and showed the plunger lubrication apparatus of this invention partially.

Explanation of symbols

1: injection sleeve, 1a: pouring spout, 2: plunger tip, 3: molding die, 3a: cavity, 4: lubricant holding member, 5: pressure reducing means, 10: inner peripheral surface (sliding surface) of injection sleeve, 20: Outer peripheral surface (sliding surface) of the plunger tip, 50: Lid member

Claims (2)

A plunger lubrication device that lubricates a sliding surface between an injection sleeve into which molten metal is poured from a hot water inlet and a plunger tip that is slidably inserted into the injection sleeve and injects the molten metal into a cavity of a mold. There,
A lubricant holding member for holding a lubricant disposed so as to face the rear end of the sliding surface of the injection sleeve and the plunger tip;
A pressure reducing means for sealing the inside of the injection sleeve and reducing the pressure to draw the lubricant held by the lubricant holding member into the sliding surface of the injection sleeve and the plunger tip;
A plunger lubrication device comprising: Plunger lubrication method for lubricating a sliding surface between an injection sleeve in which a molten metal is poured from a hot water inlet and a plunger tip that is slidably inserted into the injection sleeve and injects the molten metal into a cavity of a mold Because
The lubricant holding member impregnated with the lubricant is arranged so as to face the rear end of the sliding surface of the injection sleeve and the plunger tip,
A plunger lubrication method comprising: sealing an injection sleeve, depressurizing the inside thereof, and drawing the lubricant impregnated in the lubricant holding member into a sliding surface between the injection sleeve and the plunger tip.

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