JPS62267053A - Centrifugal dispersion apparatus having air cooling part - Google Patents

Abstract

PURPOSE:To obtain piston raw material without any shrinkage pipe on the piston top part by arranging plural air cooling holes for cooling the piston top part at the lower part of holder fixing a mold at the time of casting the piston by a centrifugal dispersion apparatus. CONSTITUTION:In a cavity 6 of the mold 3, a ring 10 consisting of inorganic or metallic fibers and inorganic powders laid near the bottom part 3a and further solid A alloy 11 for forming the piston is charged. At the time of melting the alloy 11 by heating the metallic mold 3, a core 7 having cover is inserted into the molten metal and fitted to the metallic mold 3. After that, the metallic mold 3 is fixed to the holder 2 and driven as rotating 1b around the rotating shaft 1a to execute the centrifugal casting. The molten alloy metal 11 is cooled in this process by air flowed in from the air cooling hole 4a, 4b... and 5a, 5b... to solidify toward unidirection from the piston top part to skirt part. In this way, the piston material without any shrinkage pipe on the piston top part is obtd.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Field of Application) The present invention relates to an apparatus for manufacturing biscuits for self-driving cars using a centrifugal dispersion method. It is widely used as a casting device for cylindrical sliding parts made of materials.

(Prior Art) A method for preparing a piston using the centrifugal dispersion method according to the present invention is disclosed in Japanese Patent Application Laid-open No. 60-09570 ``Method for Manufacturing Piston Made of Reinforcing Material.''

This product uses a centrifugal rotating device with a simple structure that can be cast under normal pressure, and is reinforced with inorganic fibers or metal fibers and inorganic powder in a crucible that has an inner circumference that has the same shape as the outer circumference of the product. The material is placed on the inner circumferential surface of the crucible, and a /8 hot metal or solid metal made of a light alloy is put into the crucible as a base material, heated and melted in the crucible, and then the crucible is heated to a gravity multiple of approximately 1000-3000G. After rotating while applying centrifugal force, the piston is manufactured by cooling and solidifying it.
In this field of strong gravity, the difference in specific gravity between the base material and reinforcing material in the crucible (inorganic 3.2. Mg 1.74. Aj22
．． 7), the reinforcing material moves toward the inner wall of the crucible,
A centrifugal casting technique is disclosed for producing a piston made of a composite material in which the reinforcing material is uniformly dispersed on the surface by cooling during the process of forming a dispersion layer, and the reinforcing material is not dispersed at all in the center of the swimming material.

Further, as reinforcing materials to be dispersed on the surface of the piston, inorganic fibers such as alumina fibers, wear-resistant metal fibers (FCD), and inorganic powders such as alumina are used.

(Problems to be Solved by the Invention) However, in the piston manufacturing apparatus 4o using centrifugal dispersion, since the centrifugal molding apparatus does not have a side control device for cooling the mold, the piston 31 is When the piston is built, cavities 35a, 35b, etc., which are thought to be cavities, tend to occur in the thick wall portion 32 and the piston heel 18 portion 33, and furthermore, about 1000
In the case of centrifugal compounding at a gravity multiple of ~3000G, a considerable m9 mold would be operated under high rotational conditions, which would pose a safety problem.

In order to solve this problem, a fairly large-scale safety device is required, which raises the problem of a significant increase in equipment costs.

The present invention uses the thick part of Hitosun and screws when casting a piston using a centrifugal dispersion device. - The purpose of the present invention is to provide an apparatus for producing a piston without any cavities by causing defects such as cavities that occur in the head part to be generated in the feeder part and discarding them as a yield.

[Structure of the invention]

(Means to solve the problem) The technical measures taken to solve the above technical problem are:
Inorganic fibers or metal fibers and inorganic powder having a predetermined bulk density are arranged in a randomly dispersed shape on the inner peripheral surface of a mold, which has an inner peripheral surface that has almost the same shape as the outer peripheral shape of the product piston. The base material is made of a light alloy such as A1 alloy.
8) Heat the hot metal or solid metal and heat the mold to a constant VF forming temperature. After rotating the mold while applying centrifugal force to the holder that fixed the mold, cool the mold and press the piston. In the centrifugal dispersion device manufactured by A, a plurality of air cooling holes are provided in the lower part of the holder corresponding to the top of the piston to cool the top of the piston.

(Operation) The technical means operates as follows. That is, in a swing type or rotary type casting device, inorganic fibers or metal fibers having a predetermined bulk density and inorganic powder are formed into a ring shape and placed in a portion corresponding to the piston ring at the bottom of the mold,
Molten light alloy is centrifugally cast in a mold by centrifugal force, and the bottom of the mold, which is the top of the piston, is cooled by air flowing through the air cooling hole of the holder, so that it flows in one direction from the top of the piston to the piston skirt. By causing solidification and all the gas generated from the hot water of the piston escaping to the riser part above, cavities etc. are formed in the top of the piston and the skirt part near the top of the piston, which are the most important parts of the piston. The occurrence of defects is eliminated,
Casting defects are concentrated in the riser part of the piston material, so we removed the cavities and replaced the piston material with a screw ring fitting part made of inorganic fiber with excellent wear resistance at the top of the piston. It is something that can be manufactured.

(Example) Examples will be described below.

In Figures 1 to 4, 1 is a swing type casting device;
1a is the rotation axis of the casting device, and arrow 1b indicates the rotation direction.

2 is a holder that is rotated by a device not shown! III 1
3 is a mold placed inside the holder 2. 4a, 4b, . . . and 5a, 5b, . 6 is the cavity of the light alloy that is the base material and is indicated by dotted hatching. 6a is a portion corresponding to the boss of the piston. 7 is a core having a pin boss portion/R7a and a gas vent hole 7b. 9 is a stopper made of cement, and 10 is a ring shape having a bulk density and is made of inorganic fibers or gold fibers and inorganic powder.

Describing the manufacturing method in the above configuration, a ring 10 having a predetermined bulk density made of inorganic fibers or metal fibers and inorganic powder is placed near the bottom 3a of the mold 3, and alloy 11 is poured into the solid that is the base material of the piston. It is put into a mold and made into a molten metal using an i% addition device (not shown). Next, put cement 9 in the center of the core 7 and use it as a stopper for the molten metal.
The core 7 with a lid is inserted into the molten A42 alloy at 0'C, the mold 3 is placed in the holder 2, the mold 3 is fixed to the holder 2, and the holder 2 is moved approximately as shown by the arrow 1b. 4
It rotates at 00G to solidify the /8 field, and in the process of cooling and solidifying the molten metal, the cooling holes 4a and 4b of the air cooling section
..., 5a, 5b... air flows in and out in a polar manner, and the heat of the molten metal is radiated outward in a viscous manner, so that the vicinity of the top of the piston begins to cool first, and then flows to the piston skirt. One-way solidification occurs, and all the gas generated from the molten metal in the piston rises to the upper feeder portion 13, where defects are concentrated. After the piston material has cooled, the presser stopper 9 is removed, an ejector pin is inserted through the hole, and the piston material is taken out from the stopper 7.

As shown in FIG. 3, the screw 1-bond material 12 consists of a piston part 14 and a riser part 13, and has cooling holes 4a, 4b...
, 5a, 5b..., the piston top 1
There are no evacuation nests near 4a, and gas is near 13a.
, 13b, . . . are concentrated in the pressed positive portion 13.

Next, the riser portion 13 is removed from the piston material 12 by cutting or the like to form a piston material 15 as shown in FIG. 4, which has a ring-shaped inorganic fiber composite layer near the top of the piston, and The piston material 15 without cavities can be cast.

What is shown at 20 in FIG. 5 is a rotary type centrifugal dispersion casting device, and 21 is a mold having a notch 21a for air circulation on the outside of the bottom. 22 is a core, which is inserted from the upper surface of the mold. A holder 23 fixes the mold 21. 24a, 24b... are cooling holes on the side of the holder, which are inclined with respect to the rotation direction so that air can be easily sucked.
25a.

25b... are cooling holes at the bottom of the holder, each of which has a plurality of cooling holes. Further, 23a measures the temperature with a thermocouple. 2
6 is a ring made of inorganic fiber. 27 is a split core, and 22a and 27a are gas vent holes provided in the core 22.27. 28 is a stopper made of cement that is inserted into the cores 22 and 27, 29 is a heating device for heating the mold, and 30 is a cavity for casting. 30a indicated by dotted hatching is a portion corresponding to the boss of the piston.

To describe the operation of the above configuration, a ring-shaped inorganic fiber 26 (alumina fiber diameter of 5 to 10 μm) having a bulk density (0.4 g/cut) is arranged in a ring shape in the part corresponding to the piston ring at the bottom of the mold. 200~ mold
Preheat to 400°C and use A as the base material for screws 1-
I! Pour an amount of molten Ac8a alloy (approximately 750°C) equivalent to Keetvitty, insert the core 22 and split core 27 that make the lid 28 white into the mold, and use the heating device 29 to heat it to approximately 750°C.
C. and rotated at about 300 G in the direction of arrow 35 to impregnate AC8A into one layer of alumina fiber, then the rotation and heating were stopped, and piston casting was performed.

The screw material cast using the rotary centrifugal device as described above has air cooling holes 24a,
24b... As shown by the arrow, air is sucked in and discharged from the holes 25a, 25b... on the bottom of the holder, so that the r page and thick part of the screw I/N are cooled down first, and there are no cavities. Furthermore, all the gas generated from the molten metal moves to the riser section 30b above.
The piston material is manufactured by removing the piston material.

In this way, using the centrifugal dispersion method, i! i! ! Piston ring grooves 10a and 10b are cut into a portion of the remaining piston material 14 corresponding to the piston ring made of alumina fiber to produce a screw ring with excellent wear resistance and no cavities.

〔Effect of the invention〕

The present invention has the following unique effects. In other words, by selecting R4 abrasive fillers such as alumina fibers and FCD40 fibers and combining them with the piston head and ring grooves, high G (over 100OG) was required to combine conventional fillers. However, from a relatively low G (200 G), compounding became possible due to the wettability of the filler.

In particular, by forming a total bending compound with A1 during contact with molten metal during manufacturing and heat treatment (solution treatment and aging hardening treatment) after manufacturing, the lifting platform using FCD40 filler further improves hardness and durability. This improves Fγ abrasion resistance.

In addition, low GT: Since it is possible to combine, it is better to use an extremely low-cost device because there is no load on the motor and each +I structure required for centrifugal casting equipment, and from a safety standpoint, it is highly dangerous. It is something that decreases.

Fig. 1 is a sectional view of the swing-type centrifugal dispersion device of this embodiment, and Fig. 2 is a sectional view of the mold device.
A) indicates the core, (B) the mold, and (C) the holder.

Figure 3 is a sectional view of the casting material, and Figure 4 is a sectional view of the piston material.

Figure 5, here it is! 7 is a cross-sectional view of a set of centrifugal dispersion devices,
FIG. 6 is a partially cutaway plan view of the holder, FIG. 7 is an enlarged cross-sectional view of the piston ring groove after machining, and FIG.
(A) in the figure is a sectional view of a conventional device, and (B) is a sectional view of a conventional product.

Claims (1)

[Claims] Inorganic fibers or metal fibers and inorganic powder are arranged in a dispersed manner as reinforcing materials on the inner peripheral surface of the mold, a light alloy as a base material is placed in the mold in a molten or solid state, and the mold is heated to form the mold. A centrifugal dispersion device that manufactures pistons by rotating and cooling them together with a fixed holder by centrifugal force, the centrifugal dispersion device having a plurality of cooling holes provided at the bottom of the holder to cool the top of the piston with air.