JP2001150116A - Plunger tip for die casting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plunger tip for die casting which has excellent wear resistance and lubricity and can prevent the galling and can cast with the die casting at a low cost by forming the portion needed to exchange caused by the wearing to have the small size so as to be attachable/detachable. SOLUTION: In the plunger tip 1 inserted into a plunger sleeve 43 for die casting and disposed at the front end part of a plunger 60 for pressing molten metal therein, a hollow part opening the rear part is formed at the back side of a pushing part 21 for pushing the molten metal. A connecting part 24 between a cooling water chamber 22 and a tip joint 62 at the opening part side of this cooling water chamber 22, is disposed and an annular tip end bush 3 composed of the wear resistant material and succeedingly, a short cylindrical intermediate bush 4 composed of the lubricity material are formed by fitting so as to be attachable/detachable from the tip end side on the outer peripheral surface of the cooling water chamber 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a die-casting plunger chip used in a die-casting casting apparatus.

[0002]

2. Description of the Related Art As shown in FIG. 3, a horizontal casting type cold chamber die casting apparatus 40, which is one of the die casting apparatuses used for manufacturing parts such as automobiles, communication equipment, daily necessities and cameras, has a bed 41 as shown in FIG. A fixed plate (fixed platen) 42 provided on a fixed die (fixed die) 44 is supported, and a movable platen (movable platen) 46 is mounted on the fixed die 44 from the front.
A movable mold (movable die) 47 fixed to the mold is abutted to form a cavity 48, which is the original form of a cast product, at the interface between these molds 44, 47.

[0003] This fixed type (fixed die) 44 is fitted
A cylindrical sleeve 43 is brought into contact with a sprue bush 45 communicating with a cavity 48, and is supported by a fixed plate 42.
A hot water supply port 49 for supplying molten metal is opened at a rear portion (arrow B side) protruding from the fixed plate 42 of 43.

At the time of casting, a molten metal of a die casting material such as an aluminum alloy is injected into the sleeve 43 from the hot water supply port 49 after the temperature is raised to 640 ° C. to 750 ° C. This filling ratio is about 40% of the capacity of the sleeve 43, that is, about 30% to 50%. After this injection,
The plunger tip 10 provided on the distal end side of the plunger 60 waiting near 49 is advanced in the sleeve 43 by the operation of the cylinder device 53, and pressurizes the molten metal. Casting is performed by injection injection at high speed and high pressure into the cavity 48 via the hole 52.

Since the plunger tip 10 slides back and forth inside the sleeve 43 and the sprue bush 45, the hot tool steel SKD-6 excellent in heat resistance and wear resistance is used.
It is often made of one that has been nitridated.

On the other hand, as shown in FIG. 4, the plunger 60 is formed by joining the plunger tip 10 to a hollow cylindrical plunger rod 61 connected to a cylinder device 53 via a hollow cylindrical tip joint 62. Is done.

The plunger tip 10 comes into contact with a high-temperature and high-pressure molten metal and reciprocally slides in the sleeve 43 and the sprue bush 45 at a high speed, and a large pressure is repeatedly applied. Outer surface 12
f is susceptible to damage due to wear and erosion.

[0008] Once the plunger tip 10 is damaged and irregularities occur on the surface, reciprocal sliding is not performed smoothly, and galling occurs, making it impossible to pressurize the molten metal sufficiently. The supply pressure to the cavity 48 formed by the molds 45 and 47 is reduced, and therefore, the quality of the cast product is reduced, and further, the casting operation cannot be performed.

Further, the sleeve 43 and the sprue bush 45 also come into contact with the roughened surface of the plunger tip 10, thereby causing damage or scratching.

Therefore, the plunger chip 10 needs to be replaced frequently, and is treated as a replacement part.
As shown in FIG. 7, a female screw portion 14 for screwing with the tip joint 62 is formed on the rear end side.

Further, as shown in FIG. 4, the plunger tip 10 has a front end side in contact with a high-temperature and high-pressure molten metal.
The sleeve slides inside the sleeve 43.
It is necessary to cool the so-called "biscuit", which is formed by the molten metal remaining between the pressing surface 11f of the tip of the plunger tip 10 and the wall surface of the cavity 48 in the molten metal passages 51, 52 of the gate 43 and the sprue bush 45. Therefore, the cooling water chamber 12 is provided at the center of the plunger chip 10, and the cooling water W is circulated through the passages 66 and 67, the cooling water chamber 12, and the passages 68 and 69.

The conventional plunger chip 10
As shown in FIG. 5, is formed of a metal material having excellent heat resistance and abrasion resistance and having good thermal conductivity, for example, a material obtained by quenching steel such as beryllium copper alloy and SKD61, or a steel material S45C. The material is further formed by providing a built-up portion 11f, 12f formed by plasma spraying a special alloy such as a nickel alloy or phosphor bronze on the surface of the pressing portion 11 and the cylindrical portion 12. I have. In addition, this overlay part 11
f and 12f have a thickness of about 0.5 to 0.7 mm and a hardness of about 55 to 58 HRC.

[0013]

However, in the plunger chip of the prior art, the plasma spraying of these beryllium copper alloys and special alloys formed on the surface is expensive, so that the manufacturing cost is very high. Problem.

Further, since the outer peripheral surface of the plunger tip is worn or eroded by sliding, it is necessary to frequently replace the entire plunger tip having a high manufacturing cost. There is a problem that the manufacturing cost increases.

Further, on the outer peripheral surface of the plunger tip, a built-up portion of the same material is formed in a portion where importance is placed on wear resistance on the tip side and a portion where importance is placed on lubricity on the rear side. Therefore, there is a problem that both requirements cannot always be sufficiently satisfied.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to provide a die-casting plunger tip that includes a part requiring wear resistance and a part requiring lubricity. Made of a material different from the body, has excellent wear resistance and lubricity, can prevent galling,
In addition, it is an object of the present invention to provide a die-casting plunger chip that can be die-cast at low cost by forming a portion that needs to be replaced due to wear or the like so as to be small and detachable.

[0017]

A plunger tip for die casting according to the present invention for achieving the above object is a plunger tip inserted in a plunger sleeve for die casting and arranged at a front end of a plunger for press-fitting molten metal. Forming a hollow portion having a rear portion opened behind the pressing portion for pressing the molten metal, disposing a cooling water chamber, and a connection portion with a chip joint on the opening side of the cooling water chamber, A ring-shaped tip bush made of a wear-resistant material and a short cylindrical intermediate bush made of a lubricating material are detachably fitted to the outer peripheral surface of the chamber from the tip side.

The tip bush is made of steel S45C.
The intermediate bush is formed of a beryllium copper alloy or an oilless metal.

According to the plunger tip for die casting having this configuration, a cobalt alloy having excellent wear resistance is made of a steel material S45.
The tip bush portion formed of a wear-resistant material such as that formed by spraying the surface onto C comes into contact with and slides on the plunger sleeve, so that the durability against abrasion due to the reciprocating sliding motion increases.

Since the outer peripheral side of the tip of the plunger tip in which the tip bush is disposed is in contact with a high-temperature and high-pressure molten metal, the diameter of the plunger tip expands due to thermal expansion. Therefore, the tip portion is particularly easily worn, so that abrasion resistance is strongly required.

Further, since an intermediate bush made of a lubricating material such as beryllium alloy or oil-less metal having excellent lubricating properties is provided at the sliding contact portion, the reciprocating sliding motion can be maintained smoothly, and there is no galling. Can be prevented.

Further, since parts such as the tip bush and the intermediate bush, which need to be replaced, are formed independently as small ring-shaped parts, a cobalt alloy or the like having excellent wear resistance or a beryllium copper having an excellent lubricating property can be obtained. Even if an expensive metal material such as an alloy is used, a small amount of the material is used, so that the manufacturing cost of the plunger tip can be reduced.

The term "excellent in lubricity" means that the material can slide smoothly during reciprocating sliding contact and hardly causes galling. In lubricating materials, not only a single material of alloy metal,
A material obtained by spraying a cobalt alloy on the surface of steel S45C is also included.

Further, even when the tip bush and the intermediate bush are worn, the tip bush which is easily damaged by contact with the high-temperature and high-pressure molten metal or the intermediate bush which is the center of sliding contact may be replaced. In addition, since the expensive chip body which has been processed with a special alloy on the front surface can be used as it is, the replacement of the expensive chip body is greatly reduced, the replacement cost is reduced, and the manufacturing cost of the die-cast product is reduced.

[0025]

Embodiments of the present invention will now be described with reference to the drawings.

As shown in FIGS. 1 and 2, the plunger chip 1 for die casting according to the present invention comprises a chip body 2, a ring-shaped tip bush 3 and a short cylindrical intermediate bush 4 which are mounted around the periphery of the chip body. The chip body 2 includes a pressing portion 21 for pressing the molten metal, and a cooling water chamber 22 provided with a hollow portion having a rear opening behind the pressing portion 21. And a connection portion 24 on the opening side.

That is, the chip body 2 is provided with the pressing portion 21 on the front surface.
And a cylindrical portion 23 having a cooling water chamber 22 and a connecting portion 24 therein. The connection portion 24 is formed by a female screw portion 24 so as to be connectable to the tip joint 62 shown in FIGS. The tip body 2 is formed of a hardened steel material such as a steel material S45C or the like, and the front pressing surface 21f is formed by coating a cobalt alloy to a thickness of about 0.7 mm to 1 mm by thermal spraying or the like.

The tip bush 3 and the intermediate bush 4 are fitted around the tip portion of the chip body 2 in this order from the tip side, and the screw portion 7 of the holding bush 5 is attached to the chip body 2.
And the fixing bush 5 is fixed to the chip body 2 with a set screw 6.

The tip bush 3 is connected to the tip body 2
It is formed in a ring shape so as to fit around the cylindrical portion 23 of. The tip main body 2 is formed by spraying a cobalt alloy on the surface of a steel material S45C, or is formed of a cobalt alloy, a nickel alloy, or the like, and is formed of a wear-resistant material having excellent heat resistance and wear resistance. . Also, the intermediate bush 4
It is formed in a ring shape so as to fit around the cylindrical portion 23 of the chip body 2 and is disposed at the rear of the tip bush 3. This intermediate bush 4 is made of lubricating material such as beryllium copper alloy and oilless metal. Made of excellent lubricating material.

The tip bush 3 is used for the plunger tip 1
The main part of the sliding contact is the intermediate bush 4, so that the width L1 of the distal bush 3 is smaller than the width L2 of the intermediate bush. To give an example, the shape of the chip body 2 is 1
55 mm, the outer diameter of the cylindrical portion 23 is 74 mmφ, and the outer diameters of the tip bush and the intermediate bush are 90 mmφ.
Is 75 mm.

The front end bush 3 and the intermediate bush 4 are mounted and fitted on the outer periphery of the cylindrical portion 23 of the main body chip 3 from the rear, and the holding bush 5 made of steel material S45C or the like is connected to the intermediate bush 4. Insert the chip body 2
The holding screw 6 is screwed into the screw hole 41 of the holding bush 5, and the tip is pressed into the holding hole 25 of the chip body 2 to fix the holding bush 5. Thus, the plunger chip 1 is configured.

By removing the set screw 6 and the holding bush 5, the intermediate bush 4 and the tip bush 3 can be pulled out from the chip body 2 to the rear side. That is, the tip bush 3 and the intermediate bush 4 are formed detachably with respect to the chip body 2.

According to the plunger chip 1 for die casting having the above-described structure, the outer peripheral portion of the tip, which is particularly easily worn, is formed of the tip bush 3 made of a wear-resistant material. Since the sliding contact portion with the plunger sleeve is formed of the removable intermediate bush 4 made of a lubricating material, the lubricating property is excellent, so that the sliding can be performed smoothly and galling can be prevented.

Since the end bush 3 and the intermediate bush 4 are formed in a detachable ring shape, an expensive material having excellent wear resistance is used for the end bush 3, and the intermediate bush 4 is lubricated. Even if an expensive material such as a beryllium copper alloy or an oil-less metal having excellent properties is used, a much smaller amount is required as compared with the entire main body chip 2.
The manufacturing cost of the plunger chip 1 can be reduced.

Further, even if the plunger tip 1 is formed of a material having excellent wear resistance, the outer peripheral surface thereof will eventually be worn out, so that the plunger tip 1 needs to be replaced. Since the detachable tip bush 3 is provided, only the tip bush 3 needs to be replaced at the time of damage. Even if the intermediate bush 4 forming the main part of the sliding contact portion is damaged, only the intermediate bush 4 needs to be replaced.

Therefore, it is not necessary to replace the entire plunger chip 1, and the main body chip 1 and the like can be continuously used. Therefore, the replacement cost of the plunger tip can be reduced, and the manufacturing cost of the die cast product can be reduced.

[0037]

According to the plunger chip for die casting according to the present invention, the following effects can be obtained.

A ring-shaped tip bush made of a wear-resistant material such as cobalt metal or a nickel alloy is provided on the outer periphery of the tip of the plunger tip for die casting. Is configured to abut against the plunger sleeve, so that durability against abrasion due to sliding reciprocating motion can be improved.

Further, since a short cylindrical intermediate bush made of a lubricating material such as beryllium alloy or oilless metal is disposed at the sliding contact portion on the outer peripheral portion of the cylindrical portion, the reciprocating sliding motion in the plunger sleeve is reduced. It can be maintained smoothly and can prevent sticking.

Furthermore, since expensive materials having excellent wear resistance and lubricity are used only for the tip bush of a small ring-shaped part and the short cylindrical intermediate bush, these expensive metal materials are used. In addition, the amount of use is small, and the manufacturing cost of the plunger tip can be reduced.

Even when the tip bush or the intermediate bush is worn or damaged, only the tip bush or the intermediate bush needs to be replaced. Since it can be used as it is, the frequency of replacing the expensive chip body is reduced.

As a result, the replacement cost is reduced, and the production cost of the die-cast product can be reduced. Also, the parts to be replaced are small parts such as the tip bush and the intermediate bush, which has the resource saving effect of extending the life of the relatively large chip body.In addition, each part is separately made of a wear-resistant material or a lubricating material. Since it is made and the material is easily separated, it is easy to recycle, and there is also a resource saving effect in terms of this recycling.

[Brief description of the drawings]

FIG. 1 is a view showing a plunger chip for die casting according to the present invention, wherein FIG.
(B) is a front view in which the upper half shows an XX cross section.

FIG. 2 is an exploded perspective view including a cross section of the die casting plunger tip of FIG.

FIG. 3 is a schematic view showing a die casting apparatus.

FIG. 4 is a side sectional view showing a peripheral state of a plunger chip for die casting according to the present invention.

FIG. 5 is a view showing a conventional die-casting plunger chip, in which (a) is a side view in which an upper half shows a cross section;
(B) is a front view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plunger tip 2 Tip body 3 Tip bush 4 Intermediate bush 5 Pressing bush 21 Pressing part 22 Cooling water chamber 23 Tube part 24 Female screw part (connection part)

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Seishi Katsumi 5-38-6 Takashimadaira, Itabashi-ku, Tokyo F-term (reference) 4K031 AA02 AA03 AA08 AB08 CB31

Claims (2)

[Claims] 1. A plunger tip inserted in a plunger sleeve for die casting and disposed at a front end of a plunger for press-fitting a molten metal, wherein a hollow portion having a rear portion opened behind a pressing portion for pressing the molten metal is formed. , Cooling water chamber,
A connection portion with a tip joint is provided on the opening side of the cooling water chamber, and a ring-shaped tip bush made of a wear-resistant material is provided on the outer peripheral surface of the cooling water chamber from the tip side, A plunger chip for die casting, wherein a short cylindrical intermediate bush made of a material is detachably fitted. 2. The plunger tip for die casting according to claim 1, wherein said tip bush is formed by spraying a cobalt alloy on a surface of a steel material S45C, and said intermediate bush is formed of a beryllium copper alloy or an oilless metal. .