JP2009279645A - Method for lubricating die casting plunger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent defects from occurring in die casting products as well as raise the number of useful shots per cycle by improving the method for applying a lubricant onto a die casting plunger. <P>SOLUTION: A die casting plunger comprises a structure with a plunger tip and a plunger rod that are connected by a joint located therebetween. A double passageway is provided for respectively and separately supplying air and a lubricant in the axial direction of the plunger rod, and air and the lubricant are mixed to form a mist at the side end portion of exit of the double passageway connected with the joint. The mist, in which the lubricant is mixed, is distributed via a distribution passageway to a plurality of single passageway provided at the joint, and is sprayed towards the inner surface of the plunger sleeve from the nozzle provided at each single passageway and opened towards an outer peripheral side, so that the lubricant is applied onto the inner surface of the plunger sleeve. Furthermore, when a molten metal poured into the plunger sleeve is transported to a cavity, the plunger tip is moved forward, while air is supplied to only an outside passageway in the double passageway, and the plunger tip is moved backward, while air is supplied to the outside passageway in the double passageway and, at the same time, the lubricant is supplied to an inside passageway. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method of lubricating a die casting plunger that feeds a molten metal of a die casting machine for a nonferrous metal such as an aluminum alloy to a cavity.

  In the die-cast plunger, the outer peripheral surface of the plunger tip slides on the inner peripheral surface of the plunger sleeve, so that the sliding surface is worn. In more severe cases, galling may occur. In order to suppress such wear and galling, it is common to apply a lubricant to the sliding surface to make the sliding smooth.

  However, if the application amount of the lubricant is excessive or partially excessive due to uneven application, the excess amount is entrained in the molten metal injected into the plunger sleeve as a gas or inclusion, resulting in Mixed with die-cast products, resulting in product defects. For this reason, various techniques for appropriately applying the lubricant have been disclosed.

  Patent Document 1 discloses a die casting apparatus that can apply the lubricant more evenly to the inner wall of the plunger sleeve and is excellent in maintainability. That is, a ring member provided with a plurality of discharge ports formed in the direction from the inner peripheral surface toward the outer peripheral surface in the circumferential direction at the plunger tip side end portion of the plunger rod having the lubricant supply path formed therein is provided as a discharge port. And the lubricant supply path are in communication with each other.

  According to Patent Document 1, since the lubricant can be applied more evenly and the member in which the discharge port is formed is a separable ring member, the discharge port is temporarily caused by foreign matter mixed into the lubricant. Even if clogging occurs, the casting process can be resumed simply by replacing the ring member.

  Patent Document 2 discloses an injection plunger device of a die casting machine that supplies an optimal amount of lubricant to an interface between an injection plunger tip and an injection sleeve during injection, and a lubricant application method thereof. That is, a lubricant supply hole that opens to the outer periphery of the injection plunger tip, a lubricant supply line that is provided inside the injection plunger chip and communicates with the lubricant supply hole, a heater that heats the lubricant supply line, An injection plunger device of a die casting machine comprising a lubricant supply means to a lubricant supply pipe.

  Further, in the injection plunger device of the die casting machine, when the molten metal supplied to the injection sleeve is injected into the mold by the injection plunger, the vaporized lubricant is diffused from the outer periphery of the injection plunger tip, and the injection plan. This is a method of applying a lubricant to be supplied to the interface between the jar tip and the injection sleeve.

  According to Patent Document 2, an optimum amount of lubricant is supplied to the interface between the injection plunger tip and the injection sleeve during injection, and the injection plunger tip and the injection sleeve are galled due to lack of lubricant. It is possible to stabilize the quality of die-cast products without generating them.

JP-A-2005-349452 JP 2007-245161 A

  As described above, in order to suppress wear of the sliding surface between the inner peripheral surface of the plunger sleeve and the outer peripheral surface of the plunger tip, it is necessary to apply a lubricant. However, if the amount of lubricant applied is excessive or partially excessive due to uneven application, the excess will be trapped in the molten metal as gas or inclusions and mixed into the die-cast product, resulting in product defects. Bring. For this reason, a technique for uniformly applying the minimum amount of lubricant is desired.

  Patent Document 1 and Patent Document 2 described above each improve the method of applying a lubricant. Further, in the present invention, the method for applying the lubricant is improved by a new technique to increase the number of shots to be used for the die-casting plunger and to prevent the occurrence of defects in the die-cast product.

  The present invention will be described with reference to the drawings. FIG. 1 is a sectional view of an essential part in the axial direction of a die cast plunger according to an embodiment of the present invention, FIG. 2 is an enlarged sectional view of a plunger tip, a joint, and a plunger rod, and FIG. FIG. 3 is a further enlarged sectional view of the nozzle portion in FIG. 1 or FIG. 2. The scope of the present invention is not limited to these example drawings, and includes other embodiments as long as the requirements of the present invention are satisfied.

  The invention of claim 1 of the present invention includes a plunger tip (hereinafter referred to as “chip 2” in the embodiment) and a plunger rod (hereinafter referred to as “rod 3” in the embodiment) interposed therebetween. The two flow paths 5 for supplying air and lubricant separately to the axial direction of the rod 3 are provided in the axial direction of the rod 3, and air is provided at the outlet side end 51 portion of the two flow paths 5 connected to the joint 4. And the lubricant are mixed to form a mist-like body, and the lubricant-mixed mist-like body is distributed to a plurality of one flow paths 7 provided in the joint 4 via the distribution path 6, and the outer circumference provided in each one flow path 7. A lubricant-mixed mist is sprayed from the nozzle 8 opening toward the side toward the inner surface 91 of the plunger sleeve (hereinafter referred to as “sleeve 9”) to lubricate the inner surface 91 of the sleeve 9. Die-casting plan to apply agent It is a method of lubricating a turbocharger 1.

  According to the second aspect of the present invention, when the molten metal injected into the sleeve 9 is sent to the cavity, the tip 2 is advanced while supplying air only to the outer flow path 52 of the two flow paths 5. 2. The method of lubricating a die-cast plunger 1 according to claim 1, wherein the tip 2 is retracted while air is supplied to the outer flow path 52 and a lubricant is supplied to the inner flow path 53.

  As a supplement to the drawing, FIG. 1 shows the die-casting plunger 1 with the tip 2 positioned in the middle of the sleeve 9, and the front end of the sleeve 9 on the side where the tip 2 advances in the direction of arrow F and sends the molten metal to the cavity. The rear end portion of the rod 3 that retreats in the arrow R direction is omitted. When the die casting plunger 1 is operated, the tip 21 of the tip 2 is retracted in the direction of arrow R to the vicinity of the rear end 11 of the sleeve 9 and the molten metal is injected into the pouring port 10 of the sleeve 9 in the direction of arrow M, then the tip 2 Is advanced in the direction of arrow F to feed the molten metal accumulated in the sleeve 9 to the cavity.

  1 and 2, the tip 2 and the rod 3 are coupled by screwed portions 41 and 42 with the joint 4, respectively. Although a cooling water channel 12 for cooling the chip 2 from the inner side 22 is provided through the rod 3 and the joint 4, details of the cooling system are omitted. Although not shown, the mist-like distribution passage 6 and the cooling water passage 12 at the joint are prevented from leaking to the outside by an O-ring or the like.

  The details of the two flow paths 5 in FIG. 1 are omitted because they are fine, but the two flow paths 5 have a double tube structure as shown in FIG. 2, and an inner flow path 53 is provided in an outer flow path 52. Then, the outlet side end 54 of the inner flow path 53 is set to a recessed position with respect to the outer flow path 52, and this portion constitutes a two-fluid spray nozzle. The mist containing the lubricant generated here flows to the one flow path 7 via the annular groove-shaped distribution path 6. The distribution path 6 is provided on the joint 4 side in the embodiment, but may be provided on the rod 3 side.

  In FIG. 3, eight flow paths 7 are provided in the circumferential direction, but the present invention is not limited to the number of positions in this embodiment. In FIG. 1 and FIG. 2, the upper one flow path 7 is positioned coaxially with the second flow path 5, but it is only for convenience and need not be coaxial.

  In FIG. 4, the nozzle 8 is a one-fluid spray nozzle and is embedded in the joint 4 by a screwing portion 82. The mist of the lubricant mixture can be spread and sprayed from the nozzle hole 81 toward the inner surface 91 of the sleeve 9 in the direction of arrow E. The lubricant applied to the inner surface 91 of the sleeve 9 by spraying further spreads by sliding of the chip 2 and covers the inner surface 91 of the sleeve 9 widely.

  1 and 2, the rear end side of the rod 3 is not shown, but the outer flow path 52 of the two flow paths 5 is in the direction of arrow A, and the inner flow path 53 is in the direction of arrow L (not shown). Connected). The cooling water channel 12 is connected to a water supply and drainage channel (not shown) in the direction of arrow C.

  According to the invention of claim 1 of the present invention, the lubricant is mixed with air to form a mist, and the lubricant is in a more diluted state than the case where it is alone, so that it is not applied deeply and a small amount. It becomes possible to apply even with the lubricant. And since the mixture atomized in the exit side end 51 part of the two flow paths 5 is further finely homogenized by the nozzle 8 and the atomized state is improved, the coating layer can be made thin. It can be applied with spread.

  Further, when the lubricant is distributed alone to the plurality of one flow paths 7, the lubricant is easily distributed more to the lower position than the upper position in the circumferential direction because of the liquid, and the lower position in the circumferential direction of the inner surface 91 of the sleeve 9. It is easier to apply more. In the case of the present invention, because of the mist, there is no uneven coating between the upper and lower positions.

  With these effects, the lubricant can be uniformly applied to the inner surface 91 of the sleeve 9 even in a small amount, so that product defects can be prevented and the useful life of the die cast plunger 1 can be extended.

  According to the invention of claim 2 of the present invention, when the chip 2 is advanced and the molten metal is sent to the cavity, only air flows through the distribution path 6 and one flow path 7 and is ejected from the nozzle 8. It has become. By this air flow, dirt due to the lubricant adhering to the flow path is blown away and cleaned. Further, the air blown out from the nozzle 8 blows away the dirt and the residue formed by the contact between the lubricant and the metal melt, and the sleeve 9 is cooled.

  When the tip 2 is moved backward, air is supplied to the outer flow path 52 of the two flow paths 5 and the lubricant is supplied to the inner flow path 53, but the chip 2 is sprayed on the inner surface 91 of the sleeve 9 as a mist. The applied lubricant is immediately further expanded by the sliding of the tip 2 and covers the inner surface 91 of the sleeve 9 widely. In addition, when the air at the time of forward movement is already flowing in the distribution path 6 and the single flow path 7, the mist of the lubricant mixture continues to flow without interruption at the time of backward movement. Can be applied. Furthermore, the operation of supplying and shutting off the required amount of lubricant can be made relatively simple.

  Thus, even a small amount of lubricant can be stably and uniformly applied to the inner surface 91 of the sleeve 9. And while preventing the product defect further and extending the service life of the die-casting plunger 1, the operability of the die-casting work is improved.

Example 1
An example die casting plunger 1 shown in FIGS. The main specifications are as follows.
Nominal dimensions of the sleeve 9: total length 700 mm, inner diameter 130 mm, outer diameter 210 mm
Material of sleeve 9: Hot mold steel (SKD61)
Material of chip 2: Hot mold steel (SKD61)
Rod 3 material: structural tough steel (SCM440)
Joint 4 material: structural tough steel (SCM440)
Inner diameter of outer channel 52 of two channels: 8 mm
Inner diameter of inner channel 53 of two channels: 2.5 mm
Depth of penetration from the inner channel 53 from the two channel outlet side ends 51: 30 mm
Inner diameter of one flow path 7: 2.3 mm
Nozzle hole 81 diameter: 1 mm
Distance from nozzle 8 to inner surface 91 of sleeve 9: 10 mm

Example 2
The die-casting plunger 1 prototyped in Example 1 was mounted on a horizontal die-casting machine having a clamping force of 1,650 tons, and was used for testing in die casting of an aluminum alloy (ADC12).

  As described above, when the molten metal poured into the sleeve 9 from the pouring port 10 in the direction of the arrow M is sent to the cavity, a supply device (not shown) in the direction of the arrow A is supplied only to the outer channel 52 of the two channels 5. ) To advance the tip 2 in the direction of arrow F while supplying air at a flow rate of 780 l / min. Then, air is continuously supplied to the outer flow path 52 of the two flow paths 5, and 3 cc of lubricant is supplied to the inner flow path 53 from a supply device (not shown) in the direction of arrow L at a flow rate of 5 cc / sec. The chip 2 was retracted in the direction of arrow R while supplying. With this operation, the sleeve 9 of the present invention could be used up to 30,000 shots. In addition, the occurrence of product defects was significantly reduced.

Comparative Example The comparative die-casting plunger has the same nominal dimensions as those in Examples 1 and 2, and is conventionally used for die casting of the same aluminum alloy (ADC12). A joint and a lubricant flow path are not provided as in the embodiment of the present invention, and a tip is attached to the tip of the rod. The material of the plunger sleeve and the tip is the same steel for hot mold (SKD61) as the material of the embodiment of the present invention.

  The lubrication method is a method in which the lubricant is sprayed onto the inner surface of the sleeve using an air spray while dripping the lubricant from the upper part of the pouring hole of the plunger sleeve. The required amount of lubricant per one time was 6 cc, and the durability of the die cast sleeve was 9,800 shots.

  From the results of these examples and comparative examples, the die-cast sleeve to which the present invention is applied has a service life of about three times the number of durable shots despite the fact that the required amount of lubricant is as small as about 1/2 that of the prior art. It has become clear that there is a remarkable effect on the reduction of the life and the extension of the service life. Further, it is possible to uniformly apply a small amount of lubricant to the inner surface of the plunger sleeve and to clean the inner surface of the plunger sleeve, thereby preventing product defects due to excessive lubricant and residues. In addition, since the lubricant supply and shut-off operations are relatively simple, the die casting workability is improved.

Sectional drawing of the principal part of the axial direction of the Example die-casting plunger by this invention Enlarged cross-sectional view of plunger tip, joint and plunger rod S-S arrow sectional view in FIG. A further enlarged sectional view of the nozzle portion in FIG. 1 or FIG.

Explanation of symbols

1: Die-casting plunger 2: Tip 21: Tip tip 22: Inside of tip 3: Rod 4: Joint 41: Screwing part 42: Screwing part 5: Two flow path 51: Two flow path outlet side end 52: Outside of two flow paths Channel 53: Inner channel 54 of two channels: Outlet side end of inner channel 6: Distribution channel 7: One channel 8: Nozzle 81: Nozzle hole 82: Screwing portion 9: Sleeve 91: Inner surface 10 of sleeve: Note Spout 11: Sleeve rear end 12: Cooling channel arrow F: Tip advance direction Arrow R: Rod retreat direction arrow M: Molten metal injection direction Arrow E: Spray direction Arrow A: Air supply device direction of outer channel Arrow L: Lubricant supply device direction arrow for inner flow path C: Water supply and drainage direction for cooling water Arrow S: Direction for viewing cross section

Claims (2)

  The plunger tip and the plunger rod are connected by a joint interposed between them, and two flow paths for supplying air and lubricant separately in the axial direction of the plunger rod are provided, and the two flow paths connected to the joint are provided. Air and lubricant are mixed into a mist at the outlet side end portion, and the mist of mixed lubricant is distributed to a plurality of flow paths provided in the joint via a distribution path. A method of lubricating a die-cast plunger, comprising spraying a lubricant-mixed mist from a nozzle opening toward an outer peripheral side provided on the inner surface of the plunger sleeve toward the inner surface of the plunger sleeve and applying the lubricant to the inner surface of the plunger sleeve.   When sending the molten metal injected into the plunger sleeve to the cavity, the plunger tip is advanced while supplying air only to the outer flow path of the two flow paths, supplying air to the outer flow path of the two flow paths, and to the inner flow path 2. The method of lubricating a die cast plunger according to claim 1, wherein the plunger tip is retracted while supplying the lubricant.

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