KR20060108953A - Plunger tip for die casting - Google Patents

Abstract

A plunger tip for die casting in which a portion contacted with a cylinder is made of an expensive material to prevent damage of the portion, and other portions except the portion contacted with the cylinder are made of an inexpensive material to improve price competitiveness, and a plunger tip for die casting capable of improving productivity of products by easily emitting heat or gas from the interior of the cylinder or the cylinder itself are provided. A plunger tip for die casting comprises: a plunger body(10) connected to a piston rod, moved forward and backward, and made of a casting material; and a cover ring(20) connected to an outer portion of the plunger body to protect the plunger body and made of a tool steel material. The plunger body comprises: an injection part(12) in which a hollow part is formed; a mounting part(11) in which a screw hole is formed; a ring placement part(13) having larger diameter than the injection part; a gas exhaust passage(14) comprising grooves formed on the ring placement part; and an inclined plane(15) processed in a chamfered shape on an end edge portion of the plunger body. The cover ring comprises: a plurality of holes(21) that are in communication with longitudinal grooves formed on an outer circumferential surface of the injection part; graphite powder(22) filled in the holes as a lubricating material; and an inclined plane(23) formed on an end portion of the cover ring and continued to the inclined plane(15) of the plunger body.

Description

Plunger Tip for Die Casting}

1 is a block diagram showing a typical die casting apparatus.

2 is a cross-sectional view of a conventional die casting plunger tip.

Figure 3 is an exploded perspective view showing a plunger tip for die casting according to the present invention.

Figure 4 is a perspective view of the die casting plunger tip of the present invention.

FIG. 5 is a sectional view taken along the line “A-A” of FIG. 4. FIG.

<Description of the symbols for the main parts of the drawings>

10: Plunger Body 11: Mounting Part

12: injection part 13: ring seating part

14: gas discharge passage 15: slope

16: hollow part 17: screw hole

20: Cover Ring 21: Hole

22: graphite powder 23: inclined surface

The present invention relates to a die casting plunger tip for pressurizing molten metal in a die casting apparatus and injecting it into a cavity of a mold. Particularly, it is easy to move inside a cylinder to improve work efficiency and to easily release gas and heat. It relates to a plunger tip for die casting which has been improved.

In general, die casting is performed by injecting molten metal into a steel mold that is precisely machined to completely match the required casting shape, and then cooling to obtain a casting having the same shape as the mold, or It is a precision casting method in which a molten metal in a semi-hardened state is injected into a mold while being injected. Therefore, the production of complex and thin castings is possible, and the production speed is high, and it is used for the production of various products such as body parts of precision mechanical products such as automobile parts, electric devices and optical devices, or mobile phone frames.

In addition to the advantages that the products produced by die casting are accurate in size, there is almost no need for finishing, they have excellent mechanical properties and mass production with high production speed. Molten metals used as die castings are alloys such as zinc (Zn), aluminum (Al), tin (Sn), copper (Cu), magnesium (Mg), etc., and are used in dies by pneumatic pressure, hydraulic pressure, or hydraulic pressure. After injection, it is cooled and solidified.

As shown in FIG. 1, a conventional die casting apparatus includes a mold 50 having a cavity 51 having the same shape as a required product, and a cylinder 53 installed to communicate with a cavity 51 of the mold 50. And a nozzle 55 connected to the cylinder 53 so as to supply molten metal to the inside of the cylinder 53, and a piston rod 57 disposed in a straight line with the cylinder 53 to move back and forth. , A plunger tip which is located inside the cylinder 53 and is coupled to the tip of the piston rod 57 to pressurize the molten metal introduced into the cylinder 53 to inject it into the cavity 51 of the mold 50 ( 60).

The die casting apparatus configured as described above produces a product having the same shape as the cavity by injecting molten metal into the cavity of the mold and then cooling and solidifying the mold.

When the molten metal is introduced into the cylinder 53 through the nozzle 55, the piston rod 57 is advanced, and the plunger tip 60 presses the molten metal into the cavity 51 of the mold 50. do. When the molten metal in the die 50 is cooled and solidified, the die 50 is separated and the finished product is de-carved from the cavity 51 to produce a product.

As shown in FIG. 2, the plunger tip 60 pushes the molten metal introduced into the cylinder 53 by a predetermined amount and absorbs the shock caused by the shrinkage and expansion caused by the injection of the molten metal. Screw hole 65 and piston rod 57 are formed in the inner part so that the injection part 62 formed of the hollow part 64 and the rear end of the injection part 62 and the piston rod 57 can be coupled. ) Is divided into a mounting portion 61 in which an insertion hole 66 is inserted. In addition, the tip portion of the injection portion 62 is formed with a stepped portion 63 along the circumference so that the pressure can be easily accommodated when the molten metal is injected.

Therefore, the plunger tip 60 receives molten metal introduced into the cylinder 53 while the injection portion 62 moves back and forth within the cylinder 53 as the piston rod 57 connected to the mounting portion 61 moves. By pushing toward the mold 50, the die casting process is performed in the mold 50. At this time, since the injection portion 62 is in contact with the hot molten metal, the expansion and contraction are repeated, and since the injection portion 62 is in contact with the inner circumferential surface of the cylinder 53, there is a high risk of wear in the reciprocating process.

However, in the conventional die casting plunger tip, it is difficult to discharge the gas generated during the frictional heat due to the friction with the cylinder or the cooling of the molten metal, and when the injection portion is formed thick to prevent deformation of the injection portion, the material cost is high. There is a problem that rises.

That is, when the injection unit pushes the molten metal, heat may accumulate in the injection unit by the hot molten metal, and heat may accumulate in the injection unit even by friction between the injection unit and the cylinder. The heat accumulated in the injection part is released to the outside only by heat conduction through contact with the cylinder, thereby reducing its lifespan. In addition, the gas generated during the cooling of the molten metal cannot be discharged, and the apparatus must be shut down while discharging the gas.

In addition, when the injection portion is thickened to improve the durability of the injection portion that repeats expansion and contraction by heat of molten metal, the weight is increased to increase the load on the piston rod, and expensive tool steel to secure sufficient durability. Since the manufacturing costs are increased, the material cost is lowered, which lowers the price competitiveness.

The present invention has been made in order to solve the above-mentioned conventional problems, the portion in contact with the cylinder to prevent damage by using expensive materials, the other portion is to use a low-cost material to increase the price competitiveness plunger for die casting The purpose is to provide tips.

In addition, it is an object of the present invention to provide a plunger tip for die casting, which facilitates the discharge of heat or gas in the cylinder and its own to increase the life of the cylinder and the tip replacement cycle to improve the productivity of the product.

According to the die casting plunger tip of the present invention for achieving the above object, a plunger body of the casting material is coupled to the piston rod and moved back and forth, and a cover ring of tool steel material is coupled to the outside of the plunger body to protect the plunger body It is configured to, and pressurize the molten metal introduced into the cylinder in accordance with the movement of the piston rod is to be injected into the cavity of the same shape as the required product.

In addition, according to the die casting plunger tip of the present invention, the plunger body is hollowed out to absorb the impact of the shrinkage and expansion caused by the injection of molten metal by a predetermined amount to push the molten metal introduced into the cylinder An injection part formed as a part, a mounting part having a screw hole formed at an inner part so as to form a rear end of the injection part, and the piston rod coupled thereto, and partitioning the injection part and the mounting part and allowing the cover ring to be seated. It consists of a ring seat with a larger diameter.

In addition, according to the die casting plunger tip of the present invention, the plunger body is composed of a plurality of grooves formed in the circumferential direction and the longitudinal direction on the outer peripheral surface of the injection portion and grooves formed in the ring seat portion to communicate with the longitudinal groove of the injection portion A gas discharge passage is provided.

In addition, according to the die casting plunger tip of the present invention, the cover ring is provided with a plurality of holes in communication with the longitudinal groove formed on the outer peripheral surface of the injection portion, the hole may be filled with graphite powder to serve as a lubricant. .

In addition, according to the die-casting plunger tip of the present invention, the plunger body is formed of an inclined surface of which the end edge portion is processed in the form of a chamfer, the cover ring is formed of an inclined surface continuous with the inclined surface of the end portion This will alleviate the impact of the injection and covering.

Further, according to the die casting plunger tip of the present invention, the inner diameter of the cover ring is smaller than the outer diameter of the injection portion of the plunger body to be coupled to each other through shrinkage, or the inner diameter of the covering than the outer diameter of the injection portion of the plunger body To form a large and then bonded by mutual bonding using a heat curing epoxy to combine the two.

The above features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings. Prior to this, the terms or words used in the present specification and claims are based on the principle that the inventor can appropriately define the concept of terms in order to explain the invention in the best way. It should be interpreted as meanings and concepts corresponding to

Figure 3 is an exploded perspective view showing the die casting plunger tip according to the present invention, Figure 4 is a perspective view showing the die casting plunger tip of the present invention is combined, Figure 5 is a cross-sectional view "AA" of FIG. It is a cross section.

The die casting plunger tip according to the present invention is coupled to a piston rod (not shown) and is coupled to the outside of the plunger body 10 of the casting material plunger body 10 and the plunger body 10 to protect the plunger body 10. The cover ring 20 is made of a tool steel material.

The plunger body 10 is formed by the hollow portion 16 so as to push the molten metal introduced into the cylinder (not shown) by a predetermined amount and to absorb the impact of shrinkage and expansion caused by the injection of the molten metal. The injection part 12 and a mounting part 11 having a screw hole 17 formed at an inner side thereof to form a rear end of the injection part 12 and to allow the piston rod to be coupled thereto, and the injection part 12 and the mounting part. Comprising 11 and consists of a ring seating portion 13 having a larger diameter than the injection portion 12 so that the cover ring 20 can be seated.

Here, a plurality of grooves are formed on the outer circumferential surface of the injection portion 12 in the circumferential direction and the longitudinal direction, and grooves communicating with the longitudinal grooves of the injection portion 12 are formed on the ring seating portion 13 to form a gas. The discharge passage 14 is configured, and the gas generated in the solidification process of heat or molten metal of the plunger body 10 is discharged.

In addition, the cover ring 20 is formed with a plurality of holes (21) in communication with the longitudinal groove formed on the outer peripheral surface of the injection portion 12, the graphite (22) that serves as a lubricant is formed in the hole (21) It is filled. In addition, the plunger body 10 is formed of an inclined surface 15 whose end edge portion is processed into a chamfer shape, and the cover ring 20 has an end portion thereof continuous with the inclined surface 15 of the plunger body 10. Formed inclined surface 23.

Die casting plunger tip of the present invention configured as described above is completed through the following process.

The plunger body 10 is manufactured using a material having a material such as casting or cast steel, S20C, CM, etc., and when the production is completed, the plunger treatment is completed and heat treated. Subsequently, the cover ring 20 is made of alloy steel or tool steel (JIS code: SKD61, ASTM code: H13) such as brass, aluminum brass, aluminum bronze (3 types of ALBC), or beryllium copper (Be- 銅) to form a plunger body (10). )

Here, the method of coupling the plunger body 10 and the cover ring 20 includes a shrink fit method and an adhesive method. The shrink fit method forms an inner diameter of the cover ring 20 smaller than an outer diameter of the injection portion 12 of the plunger body 10 by about 0.05 to 0.15 mm, and then enlarges the inner diameter of the cover ring 20 by heating. By inserting the cover ring 20 into the plunger body 10 in the state, it is a method of firmly coupling the plunger body 10 and the cover ring 20. In addition, the bonding method forms an inner diameter of the covering 20 about 0.05 to 0.15 mm larger than the outer diameter of the injection portion 12 of the plunger body 10, and then bonds the two together by using an epoxy for thermal curing. This is how you do it.

In addition, when the plunger body 10 and the cover ring 20 are processed, the outer portion of the injection portion 12 of the plunger body 10 and the inner diameter of the cover ring 20 are slightly processed by the mounting portion 11 to be fine. It can be in the form of tapered with a slope. This is to prevent the cover ring 20 from being deviated from the plunger body 10 when the plunger tip is moved back and forth using the tapered surface, and the ring seat 13 for preventing the cover ring 20 from being detached. There is an advantage that does not need to be processed separately.

The die casting plunger tip of the present invention produced through the above process is to be moved back and forth by the piston rod to inject the molten metal introduced into the cylinder into the cavity of the mold to allow die casting processing.

When the piston rod is advanced in the state coupled to the screw hole 17 of the mounting portion 11, the injection portion 12 formed integrally with the mounting portion 11 pushes the molten metal in the cylinder to be injected into the cavity of the mold do. The molten metal injected into the cavity of the mold is cooled and solidified by heat transfer or the like, and when the mold is separated, the molten metal solidified can take out the product formed.

Here, the deformation and damage of the injection part 12 is prevented by the cover ring 20 inserted into the injection part 12 when the injection part 12 is moved, and the hole 21 of the cover ring 20 is prevented. The graphite powder 22 inserted into the) facilitates the movement of the injection portion 10. In addition, a gas discharge passage 14 having a groove 21 formed in the hole 21 formed in the cover ring 20 and the injection part 12 and the ring seating part 13 in which gas and heat generated during cooling of the molten metal are formed. Through the exit to the rear of the mounting portion (11). The hole 21 of the cover ring 20 is filled with graphite powder 22, but there is no problem in acting as a movement path for gas and heat. As a result, the pressure in front of the injection portion 12 is lowered, and the load on the piston rod is reduced.

Although the preferred embodiments of the present invention have been described above, the scope of the present invention is not limited to such specific embodiments, and those skilled in the art may appropriately change within the scope described in the claims of the present invention. This will be possible.

As described above, according to the die casting plunger tip of the present invention, the cover ring formed of tool steel is inserted into an injection part formed of a casting, thereby improving economic efficiency by increasing productivity and decreasing manufacturing cost through increased wear resistance. The effect can be obtained.

That is, the conventional plunger tip replacement cycle formed by casting the entire plunger tip for die casting is 3 to 5 days, whereas the replacement cycle of the plunger tip according to the present invention is about 20 to 25 days. This reduced productivity is improved, compared with the entire plunger tip formed of expensive tool steel, the manufacturing cost is lowered, it is possible to improve the economics.

In addition, according to the die-casting plunger tip of the present invention, by inserting the graphite powder, which acts as a lubricant to the cover ring to facilitate the overall movement as well as to discharge the gas and heat in front of the injection portion toward the mounting portion piston rod There is an effect that can reduce the load of.

Claims (8)

In the die casting plunger tip is located inside the cylinder installed in the mold having the same shape as the required product and coupled to the tip of the piston rod to press the molten metal introduced into the cylinder to inject into the cavity of the mold, It is composed of a plunger body 10 of the casting material is coupled to the piston rod and moved back and forth, and a cover ring 20 of the tool steel material is coupled to the outside of the plunger body 10 to protect the plunger body 10 Plunger tip for die casting. The method of claim 1, The plunger body 10 is an injection formed inside the hollow portion 16 so as to push the molten metal introduced into the cylinder by a predetermined amount and absorb the shock due to the contraction and expansion caused by the injection of the molten metal. A mounting portion 11 having a screw hole 17 formed at an inner side thereof to form a portion 12, a rear end portion of the injection portion 12 and the piston rod can be coupled, and the injection portion 12 and the mounting portion 11 ) And a ring seating portion (13) having a larger diameter than the injection portion (12) so that the cover ring (20) can be seated. The method of claim 2, The plunger body 10 is connected to the ring seating portion 13 so as to communicate with a plurality of grooves formed in the circumferential direction and the lengthwise direction on the outer circumferential surface of the injection portion 12 and the longitudinal groove of the injection portion 12. Die casting plunger tip characterized in that it comprises a gas discharge passage (14) consisting of a groove formed. The method according to claim 1 or 3, The cover ring (20) is a die casting plunger tip characterized in that it has a plurality of holes (21) in communication with the longitudinal groove formed on the outer peripheral surface of the injection portion (12). The method of claim 4, wherein The cover ring 20 is a die-plunger tip for die casting, characterized in that the hole filled with graphite powder (22) to serve as a lubricant. The method of claim 1, The plunger body 10 is formed of an inclined surface 15 whose end edge portion is processed into a chamfer shape, and the cover ring 20 is an inclined surface whose end portion is continuous with the inclined surface 15 of the plunger body 10. Die casting plunger tip, characterized in that formed by (23). The method of claim 1, Die casting plunger tip, characterized in that to form a smaller inner diameter of the cover ring 20 than the outer diameter of the injection portion 12 of the plunger body 10 through the shrinkage. The method of claim 1, Die casting plunger tip, characterized in that the inner diameter of the covering 20 is formed larger than the outer diameter of the injection portion 12 of the plunger body 10, and the two are bonded by mutual bonding using a thermosetting epoxy.

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