JP4254571B2 - Die casting machine lubrication equipment - Google Patents

Description

  The present invention relates to a lubrication device for a die casting machine, and more particularly to a die casting machine comprising an injection sleeve facing a product shape space of a mold and an injection plunger slidably inserted in the injection sleeve. The present invention relates to a lubrication apparatus for the purpose of lubrication between plungers.

Patent Documents 1 and 2 are known as lubrication devices for lubrication at a sliding portion between an injection sleeve and an injection plunger slidably inserted in the die casting machine. In those described in Patent Documents 1 and 2, both have a structure in which the lubricant introduced from the outside is discharged from a part of the injection plunger and the sliding portion between the injection sleeve and the injection plunger is so-called forced lubrication. It has become.
JP-A-62-220265 (FIG. 1) Japanese Patent Laid-Open No. 7-276025 (FIG. 2)

  In the conventional techniques represented by Patent Documents 1 and 2, the main focus is only on supplying the lubricant to the sliding portion between the injection sleeve and the injection plunger, and for example, it accumulates in the injection sleeve. Since the treatment of the lubricant is not taken into consideration at all, there is a concern that the secondary failure due to the lubricant may occur.

  For example, when the molten metal is injected (supplied) into the injection sleeve prior to casting, the molten metal comes into contact with the lubricant remaining in the injection sleeve, and at that time, gas due to thermal decomposition is generated, Unreacted oil and graphite that are not gasified remain as residuals. The generated gas and residue are entrained in the molten metal at the time of injection, causing not only casting defects but also deterioration of mechanical properties and defective pressure leakage. In addition, in the case of castings with heat treatment, appearance defects called “blister” and “blister” are caused on the product surface during the solution treatment, and in the case of vacuum casting, an injection sleeve is used. The lubricant in the injection sleeve leaches out as the inside and product shape portion space is depressurized, which further promotes the above problem.

  In particular, when high quality (high strength, low defect) casting products are required, it is effective to reduce the amount of lubricant used to suppress the occurrence of the above problems. An operation failure called “galling” of the injection plunger occurs, and deterioration of the filling condition at the time of injection leads to deterioration of casting quality, which is not preferable. In addition, abnormal wear of the injection tip occurs due to the occurrence of the “galling” phenomenon, and the injection of molten metal toward the reflection direction called “backflush” at the time of injection, especially in the case of vacuum casting, due to a decrease in the degree of vacuum Similar to the above, the casting quality is deteriorated.

  The present invention has been made paying attention to such a problem, and in particular, while supplying lubricant to the sliding portion of the injection sleeve and the injection plunger from the outside for forced lubrication, at the same time, excessive lubrication in the injection sleeve It is an object of the present invention to provide a lubricating device for a die casting machine that prevents the occurrence of secondary problems due to forced lubrication by adding a function of actively sucking the agent to the outside.

  The invention according to claim 1 includes an injection sleeve facing the product shape portion space of the mold and an injection plunger slidably inserted in the injection sleeve, and the molten metal poured into the injection sleeve is injected into the injection plunger. The die casting machine lubrication device is configured to fill the product shape portion space by the forward movement of the nozzle, and the lubricant discharge port is opened on the outer peripheral sliding surface of the injection plunger, and from the discharge port during the forward movement of the injection plunger While the lubricant is discharged, the lubricant in the injection sleeve is sucked by using the discharge port as a suction port during the backward movement of the injection plunger.

  In this case, as described in claim 2, it is possible to improve the sealing performance by mounting a seal material capable of expanding and contracting on the distal end side of the injection plunger from the discharge port on the outer peripheral sliding surface of the injection plunger. It is preferable for improving the effect of scraping off the lubricant on the wall surface of the injection sleeve.

  Therefore, according to the first aspect of the present invention, when the molten metal is filled into the product shape space from the injection sleeve side, that is, when the injection plunger moves forward, the necessary lubricant is discharged by discharging the lubricant from the discharge port. Supply. In this case, the lubricant is accumulated in the injection sleeve in some form as the injection plunger moves forward.

  Therefore, when the injection plunger is retracted, the above-mentioned discharge port is used as a suction port, and the lubricant in the injection sleeve is sucked each time, thereby avoiding a situation where excess lubricant is accumulated in the injection sleeve. can do. This makes it possible to extremely reduce the lubricant that will react with the molten metal during the next injection.

  According to the first aspect of the present invention, when the injection plunger moves forward, the lubricant is discharged from the discharge port formed in the outer peripheral sliding surface, and when the injection plunger moves backward, the discharge sleeve is used to discharge the lubricant. Since the lubricant inside is sucked in, the required lubrication performance can be obtained by supplying the minimum amount of lubricant, the waste of the lubricant can be reduced, and the lubricant remaining in the injection sleeve can be reduced. Since it can be removed, there is an effect that secondary troubles due to the residual lubricant, that is, the generation of gas and the like can be suppressed by extremely reducing the lubricant that reacts with the molten metal at the next injection.

  FIGS. 1A and 1B are diagrams showing a more specific embodiment of the present invention. In particular, FIG. 1A shows the overall configuration of a lubricant supply system including a die casting die. B) shows an enlarged view of the injection plunger in FIG.

  As shown in FIG. 1A, the mold 1 includes a fixed mold 3 attached to the fixed platen 2 and a movable mold 5 attached to the movable platen 4 as is well known. 5, the mold clamping and mold opening are performed, and a product shape portion space R as a cavity is formed between the fixed mold 3 and the movable mold 5 at the time of mold clamping.

  Further, the fixed platen 2 and the fixed mold 3 are provided with an injection sleeve 6 so as to pass through them. When the mold is clamped, the tip of the injection sleeve 6 faces the product shape part space R, and the injection sleeve 6 is injected. A solid cylindrical injection plunger (injection tip) 8 integral with the injection rod 7 is slidably inserted in the sleeve 6.

  As shown in FIG. 2B, the injection plunger 8 is formed with two annular grooves 9 and 10 having a predetermined depth on the distal end side of the outer peripheral sliding surface which is a cylindrical surface. . One annular groove 10 is provided with, for example, a piston ring-shaped sealable ring 11 as a sealing member, and the other annular groove 9 is a lubricant formed inside the injection plunger 8 itself. The front end portion of the port 12 is opened as a lubricant discharge port 13. As will be described later, the lubricant port 12 is connected to a pipe 14 serving as a lubricant supply / discharge passage serving both as a lubricant supply and suction.

  Since the seal ring 11 can be contracted and expanded, the diameter of the seal ring 11 is set to be slightly larger than the diameter of the injection plunger 8 in the free state. When inserted, the seal ring 11 is slightly reduced in diameter so as to be in pressure contact with the inner peripheral surface of the injection sleeve 6.

  The pipe 14 is connected to a pump 16 serving as a lubricant pumping means via a direction switching valve (for example, a three-position electromagnetic switching valve) 15 as shown in FIG. After the lubricant stored in 17 is sucked up, it is pumped and supplied to the lubricant discharge port 13 side on the injection plunger 8 side. A branch pipe 18 branched from the direction switching valve 15 is provided with an oil trap 20 and a filter 21 in addition to a vacuum pump 19 serving as a lubricant suction means. The branch pipe 18 is finally connected to the lubricant tank 17. It is here. Note that the oil trap 20 and the filter 21 function as a lubricant cleaning means for removing foreign matters and the like contained in the lubricant to be returned to the lubricant tank 17 as will be described later.

  According to the lubricating device configured in this way, as shown in FIG. 1A, the mold 1 is clamped and the injection plunger 8 is retracted from the pouring port (not shown). The molten metal is poured into the injection sleeve 6.

  When the pouring of the injection sleeve 6 is completed, the direction switching valve 15 is switched, and the supply of the lubricant is started by switching the pipe 14 to the pump 16 side. The injection plunger shown in FIG. The lubricant is discharged from the lubricant discharge port 13. At the same time, the injection plunger 8 starts moving forward together with the injection rod 7 to the injection completion position, and the molten metal in the injection sleeve 6 is filled into the product shape portion space R of the mold 1 while being injected.

  The lubricant discharged from the lubricant discharge port 13 spreads in the annular groove 9 as shown in FIG. 1B, and the sliding portion between the injection plunger 8 and the injection sleeve 6 is in the form of so-called forced lubrication. Lubricate evenly. Further, since the seal ring 11 is mounted on the tip end side of the injection plunger 8 with respect to the annular groove 9, leakage of the lubricant to the tip end side of the seal ring 11 is prevented in advance, and the necessary minimum It becomes possible to lubricate efficiently by supplying the lubricant. This is particularly advantageous in the case of so-called reduced pressure die casting or vacuum die casting in which the product shape portion space is preliminarily decompressed or evacuated to fill the molten metal, and can also contribute to improvement of the degree of decompression or the degree of vacuum.

  Even if the injection plunger 8 is temporarily stopped at the injection completion position, the injection plunger 8 still leaves a slight advance stroke to the most advanced position.

  When the injection of the molten metal is completed, the direction switching valve 15 is switched again, and the supply of the lubricant and the discharge from the lubricant discharge port 13 are stopped.

  Thereafter, the mold 1 is opened while the injection plunger 8 is in the injection completion position with respect to the injection sleeve 6 to release and remove the casting that is the product.

  When removal of the casting is completed, the injection plunger 8 moves forward with the remaining stroke to the most advanced position, and the tip of the injection plunger 8 and a part of the injection sleeve 6 at the most advanced position are next moved by the existing air blow nozzle. In order to prepare for the next shot, it receives an air blow for cleaning for the purpose of removing a cast flash or the like.

  When the air blow is completed, the direction switching valve 15 is switched, and the pipe 14 is switched to the branch pipe 18 on the vacuum pump 19 side. Through the pipe 14, the lubricant discharge port 13 on the injection plunger 8 side, and thus FIG. A negative pressure suction force acts on the annular groove 9 shown in FIG. At the same time, the injection plunger 8 starts to move backward, and the injection plunger 8 sucks excess lubricant adhering to the sliding portion with the injection sleeve 6 using the lubricant discharge port 13 as a suction port, It will retreat to the last retracted position shown in FIG.

  At this time, since the space between the injection plunger 8 and the injection sleeve 6 is sealed by the seal ring 11 as described above, the negative pressure suction force leaks into the space on the tip side of the seal ring 11. And the suction of the lubricant is performed efficiently. Further, in the process in which the seal ring 11 that is in pressure contact with the inner peripheral surface of the injection sleeve 6 moves backward together with the injection plunger 8, it serves to scrape off the lubricant adhering to the inner peripheral surface of the injection sleeve 6. Excess lubricant is efficiently collected in the annular groove 9, and as a result, the suction efficiency of the lubricant is greatly improved.

  The lubricant sucked into the branch pipe 18 is separated and removed by the oil trap 20, passes through the filter 21 from the drain port, and finally returns to the lubricant tank 17. The lubricant thus returned to the lubricant tank 17 is circulated and reused. In this case, since the oil trap 20 is provided at the front stage of the vacuum pump 19, it is possible to prevent a failure of the vacuum pump 19 due to the biting of foreign matter.

  Thus, one cycle of die casting including supply of lubricant and suction operation is completed.

  Here, when it is necessary to further increase the supply capability and suction capability of the lubricant, the lubricant port 12 is set every 90 degrees in the circumferential direction of the injection plunger 8 as shown in FIG. Alternatively, four or two positions are provided every 180 degrees (FIG. 2 shows an example where two positions are provided every 180 degrees), and the tip of each lubricant port 12 is a common annular shape as the lubricant discharge port 13. The groove 9 may be opened.

  Further, as shown in FIG. 3 as a third embodiment, a porous member 22 such as sintered metal is attached to a portion corresponding to the annular groove 9 in FIG. 2 where the lubricant discharge port 13 is opened. The equivalent function is also demonstrated.

  As described above, according to each embodiment of the present invention, the supply of the lubricant to the sliding portion between the injection sleeve 6 and the injection plunger 8 and the suction thereof can be stably performed.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows more concrete embodiment of this invention, (A) is sectional explanatory drawing of the metal mold | die for die-casting containing a lubricant supply system, (B) is a principal part expansion of the injection plunger in the figure (A). Figure. The principal part enlarged view of the injection plunger which shows the 2nd Embodiment of this invention. The principal part enlarged view of the injection plunger which shows the 3rd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Mold 3 ... Fixed type 5 ... Movable type 6 ... Injection sleeve 8 ... Injection plunger 9, 10 ... Annular groove 11 ... Seal ring (seal member)
DESCRIPTION OF SYMBOLS 12 ... Lubricant port 13 ... Lubricant discharge port 14 ... Piping 16 ... Pump (lubricant pressure feeding means)
17 ... Lubricant tank 19 ... Vacuum pump (lubricant suction means)
20 ... Oil trap (lubricant cleaning means)
21 ... Filter (lubricant cleaning means)
R ... Product shape space

Claims (5)

An injection sleeve that faces the product shape space of the mold and an injection plunger that is slidably inserted in the injection sleeve. The molten metal poured into the injection sleeve is moved into the product shape space by the forward movement of the injection plunger. A die casting machine lubrication device for filling,
Open the lubricant outlet on the outer peripheral sliding surface of the injection plunger,
A die casting machine characterized in that lubricant is discharged from its discharge port during the forward operation of the injection plunger, while the lubricant in the injection sleeve is sucked by using the discharge port as a suction port during the backward operation of the injection plunger. Lubrication equipment.   2. The lubrication apparatus for a die casting machine according to claim 1, wherein a sealing material capable of expanding and contracting is mounted on the distal end portion side of the injection plunger from the outer peripheral sliding surface of the injection plunger. Connecting the discharge port to a lubricant pumping means and a lubricant suction means outside the injection plunger;
3. The die casting machine according to claim 1, wherein the supply of the lubricant to the discharge port is performed by a lubricant pressure feeding unit, and the suction of the lubricant from the discharge port is performed by a lubricant suction unit. 4. Lubrication device.   4. The lubrication apparatus for a die casting machine according to claim 3, wherein the lubricant sucked by the lubricant sucking means is returned to the lubricant tank for circulation and reuse.   5. The lubrication apparatus for a die casting machine according to claim 4, wherein a lubricant cleaning means is provided in the middle of a path connecting the discharge port and the lubricant suction means.

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