JPS5982552A - Piston of internal-combustion engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to an internal combustion opening screw made of a light alloy according to the present invention.

Conventionally, light alloy materials such as aluminum alloys have often been used for pistons for internal combustion engines in order to reduce weight and reduce thermal forces. However, light alloy materials such as aluminum alloys have a higher thermal expansion rate than iron. Because the rate is so large,
A problem with light alloy internal combustion engine pistons, especially diesel engine pistons, is that they tend to seize with the cylinder in the so-called top land between the first ring groove and the top surface of the piston. Also, since light alloy materials usually have a lower melting point and lower heat resistance than iron, there is a problem that melting damage easily occurs in the head part of screws made of light alloy materials. be.

Conventional measures to solve these problems include I.
・Measures were adopted to increase the heat capacity of that part by widening the width of the piston, but in this case, the weight of the piston increased and there was an opening angle that went against the purpose of weight reduction by using light alloy material II. Further, there are problems such as the height of the engine becomes large and fluttering is more likely to occur.

Furthermore, in order to particularly prevent seizure, the clearance between the piston and the cylinder has been increased, but in this case there are problems in that the oil consumption mark increases and the engine noise increases. In order to prevent melting damage and seizure, the top land and head parts of the piston are coated with Alsil alloy, but in this case, the bond with the base material is not necessarily sufficient to prevent leakage. As a result, there is a problem in that the walnut layer of the Alsil alloy is likely to peel off, and furthermore, in manufacturing, there is a problem in that castability and workability are poor, resulting in a decrease in productivity.

This invention has been made in view of the above circumstances, and provides a light alloy that effectively prevents seizure of the J-tube brand and melting damage of the I-tube brand and the head without causing the problems described above. The object of the present invention is to provide an internal combustion side piston mainly made of material.

[In other words, the piston of the present invention has a top land portion and a head portion of the piston closure made of a light alloy material compositely integrated with fibers having heat resistance and a coefficient of thermal expansion lower than that of the light alloy material, This suppresses the thermal expansion of the one-piece brand to prevent seizure, and improves the heat resistance of the top land and head to prevent melting damage.

The piston of the present invention will be explained in more detail below.

FIG. 11 shows an example of a piston of the present invention, in which a piston base 1 having the shape of a piston as a whole is made of a light alloy material II such as an aluminum alloy or a magnesium alloy. The entire portion surrounded by the surface (periphery) of the top land 4 between the top surface 2 and the first ring groove 3, that is, the portion including the top land 4 and the piston top surface (head) 2 is coated with the light alloy material. Fibers 5 having a lower coefficient of thermal expansion and higher heat resistance than the above are embedded, and that portion is made up of a 11 miscellaneous/light alloy composite material layer 6 in which light alloy and fibers 5 are compositely integrated.

In the above-mentioned m-thread/light alloy composite layer 6, since the coefficient of thermal expansion in the composite material is lower than that of the light alloy material r1, the coefficient of thermal expansion as a whole is lower than that of the light alloy material alone. is also lower. Therefore, the expansion of the outer diameter of the top land 4 due to thermal expansion is suppressed, and as a result, seizure between the surface of the top land 4 and the cylinder is effectively prevented. In addition, by using fibers with excellent heat resistance, the composite material layer 6
heat resistance is superior to that of light alloy alone, resulting in melting of the top land 4 or damage to the piston top surface (head) 2.
Melting loss is effectively prevented.

The IQ Iff may be any material that has a thermal expansion coefficient lower than that of the light alloy material of the piston base body 1 and has heat resistance as described above, but in addition, IQ Iff may be made of a material that is composite and integrated with the light alloy material i11. It is desirable that the material has high wear resistance and excellent strength. From this perspective, 81!
Long fibers such as 203 (7 lumina), 5iC (silicon vi), carbon, or the same △Q203〇89203 5i
O2 (alumina-silica), carbon, etc., as well as SiC, Si3N4 (nitride 1↓ element), K2 T
It is preferable to select and use he 0+3 (potassium butanate), heino J-, and the like.

The orientation of the fibers is most preferably along the circumferential direction or having a component along the circumferential direction in order to effectively suppress the thermal expansion of 1 to 2 strands. In other words, when long fibers are used, the plain woven fabric 7 is rolled into a circumferential (spiral) shape with the warp threads 8 or weft threads 9 along the circumferential direction, as shown in FIG. Using the fiber molded body 10, it is embedded in the light alloy of the piston base material 1 so that the axis of the fiber molded body 10 and the @ line of the piston match as shown in FIG. 3, and the composite material layer 6 is formed. It is desirable to form. In addition, when long fibers are used, the same plain woven fabric 7 is used, and as shown in FIG. m
The composition body 10 may be formed into a single body with a light alloy material in the same manner as described above. On the other hand, when short ropes or whiskers are used, for example, as shown in FIG. It is desirable to use a three-dimensionally randomly oriented cylindrical fiber molded body to composite and integrate it with the light alloy material of the base 1 in the same manner as described above.

Note that the blending ratio of fibers in the composite material layer 6 is desirably within a range of approximately 10 to 60% in terms of 1 volume ratio. 1
If the groove is 0%, the effect of suppressing thermal expansion to prevent seizure and the effect of improving heat resistance to prevent melting loss will not be sufficiently achieved, while if it is 6096 or more, it will not be possible to combine it with light alloy material. becomes industrially difficult.

Next, the method for manufacturing the bis-i-n of the present invention as described above will be explained.

Long l in advance! A fibrous molded body like a bow is formed using a cloth, short fibers, or a whistle. Then, this cloth molded body is preheated as necessary, and then, for example, high-pressure casting is performed at a predetermined position in the mold, that is, a light alloy material v! 1. Place the compound in the desired area, and in that state pour molten aluminum alloy or magnesium aigura into the mold, and immediately add 500 to 1500 kL / molten metal into the molten metal in the mold with a pressure plunger.
By performing so-called high-pressure casting by applying a high pressure of approximately 300 m, the molten alloy is densely impregnated into the gaps between the sleeves of the fiber molded body, and the pressing force is maintained until solidification is completed. Then, after solidification, it may be taken out from the mold and subjected to appropriate heat treatment and finishing processing.

You j! Instead of using a fibrous molded body such as the above, short fibers or whiskers may be applied or sprayed onto required locations in the mold, and in this state the molten aluminum alloy may be dried and pressurized.

In addition, if the chess silk ratio in the composite material layer may be relatively small, the above-mentioned 500 to 1500 kO/c/
In addition to the high-pressure casting method of about 500 kQ/C, it is possible to use a pressurized casting method at a low pressure of about 500 kQ/C or less.

Below, an experimental example for producing bis-lone according to the present invention will be described.

Example 4 Outer diameter 90 for M2200cc deep pill engine
A prototype screw with a diameter of 1 mm was manufactured as follows. That is, first, a plain woven fabric of silicon carbide fiber (Nippon Carbon Co., Ltd.'#; trade name: Kanikalon) was wound into a cylinder shape with a diameter of 9Q mm and a height of 10 mm. The lt molded body is 19. Next, this Il fiber molded body was preheated to about 800°C, placed at the bottom (corresponding to the top of the piston) in a high-pressure casting mold for casting a piston, and immediately heated to about 740°C JIS.
Pour the molten aluminum alloy of AC8Δ and hold it with a pressurizing plunger until 1000 k (applying a pressure of 1/ant and applying that pressure to the aluminum alloy melt) is completely solidified, and after solidifying, pour it into the mold. Take out from-C
After heat treatment, it was processed into a piston.

As mentioned in 1 (1), it was confirmed that the part surrounded by the circular surface of the piston was uniformly composited with aluminum alloy and silicon carbide fiber throughout. .Here, the 8J string volume ratio of the recycled material layer is 30.
It was written in %. In addition, when this piston was assembled into a diesel engine and a practical test was conducted, it was confirmed that seizure of the top land 1) [・ryJ and melting loss of the top surface of the two lands and bismine did not easily occur.

As described above, according to the internal combustion m opening piston of the present invention,
The top land part of the top of the piston and the light alloy 1 of the head part are made of light alloy material r1 such as aluminum alloy.
4 (Since a cloth with a lower coefficient of thermal expansion and better heat resistance than 1 was embedded and that part was covered with fiber 7/' light alloy composite R1, thermal expansion in the top land part was suppressed. Seizure between the pi cylinders is effectively prevented, and the heat resistance of the l-twin brand and the top surface of the screw latch is also improved to effectively prevent melting damage.Furthermore, according to the present invention, In pistons, the composite integration of fibers and light alloys prevents seizure and melting damage of the 1-tube bolts, so the screws 1- It does not cause an increase in engine load or engine height, or an increase in overall consumption or engine noise, and there is no risk of peeling of composite parts. Effects are also performed.

[Brief explanation of the drawing]

FIG. 1 shows an example of the screw I/N of this invention [t 17
6 is a perspective view, FIG.
Figure 1jli is a cutaway perspective view of a piston using a layered molded body, and Figures 4 and 5 are perspective views showing an example of the bending of the molded body of the fiber eaves used in the piston of the present invention. be. 1... Bismine base, 2... Bismine top surface (
Head) 4...Toprant Alloy i for summer white. Applicant 1st and 3rd Jidosha Co., Ltd. Agent Yutaka, IH specialist 1) Hisashi Take (one idiot) Figure 1 Figure 3 Figure 2 Figure 4

Claims (1)

[Claims] Fibers having heat resistance and having a coefficient of thermal expansion smaller than that of the light alloy material are embedded in the piston base part 1 to the two-piece brand part J3 and the head part made of the light alloy material r1.
・Twin brand part and head part are 419 it,
-'A piston for internal combustion 1tIlrIiJ, characterized in that it is made of a light alloy composite material.