JPS63243237A - Frm wear-resistant parts containing graphitic carbon fiber - Google Patents

Abstract

PURPOSE:To decrease the wear of mating materials of the titled parts while the wear resistance of said parts is maintained by incorporating, as a fibrous reinforcing material, a specific amount of graphitic carbon fiber in the parts consisting of the fiber reinforced type of metal based composite material. CONSTITUTION:The fiber reinforced materials such as inorganic fiber, metallic fiber and whisker and the metallic materials of an Al alloy as the matrix, Mg alloy, etc., are molded by a pressure molding method such as a die casting method and high-pressure casting to obtain the parts of an engine, etc. In this case, 1-5vol.% (ratio for the total) graphitic carbon fiber is at least compounded into the parts as the above-mentioned fiber reinforced material. There is no effect in the addition ratio of <1vol.%, and the lubricating effect can not be obtd. above that but the wear resistance thereof is rather damaged at the time of adding >5vol.% graphitic carbon fiber to the material.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to FRMtl wear parts, and more particularly to FRM wear-resistant parts that can reduce wear of mating materials and are suitable for sliding parts for engines, motors, and other machines.

(Conventional technology) In recent years, research and development of composite materials has been active, especially FRM.
The fiber-reinforced metal matrix composite material, abbreviated as
Research is being actively conducted to use it in motors and other mechanical sliding parts.

This FRM component generally uses non-ferrous metals such as aluminum, magnesium, copper, etc. or alloys thereof, or ferrous materials such as cast iron as a matrix, and SiC as a fiber reinforced material.

Inorganic fibers such as Ax z O3, B, Ni, W, Cu
, Fe, metal fibers such as stainless steel, or 5iC1
Whiskers such as Si, N, etc. are used.

In order to manufacture FRM parts from these matrices and fiber-reinforced materials, it is common to compose them by pressure forming them using methods such as die casting and high-pressure casting, but there are also methods such as sintering, autoclaving, Methods such as hot pressing are also used.

For example, as proposed in JP-A No. 59-20443, it is common to use aluminum or an aluminum alloy as the matrix;
As proposed in Publication No. 41979, in addition to aluminum or its alloys, cast iron, copper, magnesium, or their alloys may be used as a matrix, and combinations of composite materials according to the characteristics required for the application are being researched. ing.

In this respect, F
When making RM parts, the matrix is usually made of aluminum alloy, cast iron, etc. for practical use, and Si is added to this matrix.
C, AQ20. F
Although this is an RM component, it is said that it is necessary to use ceramics such as SiC as the mating material.

(Problem to be solved by the invention) This is because when a steel material is used as a mating material, the wear of the steel material becomes severe. Therefore, the sliding surface must be chilled, induction hardened, or carburized. Inexpensive steel materials that have undergone such treatments cannot be used. Therefore, ceramics with particularly excellent wear resistance must be used as the mating material.

However, in this case, ceramics are not only more expensive than steel materials, but also difficult to process, and there are also problems with reliability, so even if the characteristics of FRM parts can be improved, There is a problem in that steel materials, which are ordinary sliding members, cannot be used in combination with this, and it is currently difficult to put them into practical use.

The present invention has been made in order to solve the problems of the prior art described above, and is an FRM resistant material for engines, etc., which can improve its own wear resistance and can use ordinary inexpensive steel materials as a mating material. The purpose is to provide wear parts.

(Means for Solving the Problems) In order to achieve the above object, the present inventor investigated the reasons why conventional FRM parts cannot use steel materials as mating materials, and found that the wear resistance of the FRM parts themselves Although research has been conducted to improve the wear resistance of FRM parts, it has been found that the basic characteristics of improving the wear resistance of FRM parts in relation to the wear of mating materials have not been clarified.

Therefore, we investigated various materials that could satisfy both the wear resistance of FRM parts and the wear of mating materials, especially reinforcing fiber materials, and found that graphite carbon fiber, which had not been given much attention in the past, was used. We have found it suitable and hereby form the present invention.

That is, the present invention provides an engine obtained by a pressure forming method such as a die-casting method or a high-pressure casting method using a fiber-reinforced material such as an inorganic fiber, a metal fiber, or a whisker, and an AQ alloy, Mg alloy, or other metal material as a matrix. In parts such as for use, at least 1 to S as the fiber reinforced material.
The gist of the present invention is an FRM wear-resistant part containing graphitic carbon fiber, characterized in that it is a composite material containing graphitic carbon fiber of voΩ%.

The present invention will be explained in detail below.

First, the inventor conducted a wear test on FRM parts assuming a cam tappet as a basic test.

The material combination for normal cam tappet material is Fe12
This is a combination of chilled 848C (tappet) and induction hardened 848C (cam).In contrast, the tappet material is A9 alloy (component (wt%): Cu
2% to 4% Si, 7.5% to 9.5% Si, remaining AM, squeeze cast product), this AQ alloy is used as a matrix and AQ20. A wear test was conducted for each case in which 10voQ% of lJi fibers were combined. The results are shown in FIG.

As shown in Fig. 2, the wear test was carried out by rotating a disk (mating material) 1 corresponding to a cam at a speed of 3,5 +1/s, and applying a surface pressure of 40 kg to a member 2 corresponding to a tappet.
/am” and add oil to the contact surface for 20 minutes.
The amount of wear after 0 hours was measured for both.

In addition, the total wear amount, which is the sum of the wear amounts of both, was also evaluated.

As is clear from Figure 1, when AQ alloy is used as the tappet material, the amount of wear on the mating material is small at 6 μm, but the amount of wear on itself is large at 220 μm, and the total amount of wear is 226 μm, which is higher than normal wear. Tappet material Fe1
Approximately 12 when using 2 (total wear amount 19μm)
It reaches twice as much.

On the other hand, when FRM made of 7 trixes of the above Af1 alloy and 10voQ% of AQ2O1 fibers is used for the tappet, the total wear amount is 29 μm, which is lower than when only these 10 alloys are used for the tappet 1. It decreases to 1/7.8.

However, the amount of wear on the mating material increased from 6 μm to 13 μm, indicating that the use of such an FRM increases the aggressiveness of the mating material.

On the other hand, using the above 10 alloys as a matrix, AQ2
When tested with a tappet made by mixing 5 vo Q% of 0.1m fiber and graphite carbon fiber (chopped fiber), the aggressiveness against the mating material was 1/6th compared to the case where carbon fiber was not mixed. 5
Furthermore, the total amount of wear was 19 μm, which was at the same level as the combination of ordinary materials. The amount of wear on itself was almost the same as when no carbon fiber was mixed. By making FRM in this way, the density is about 2.8
In addition to the advantage of reducing weight in terms of g/cc, it is possible to significantly reduce the amount of wear on the mating material while maintaining its own wear resistance, so it is possible to use ordinary steel materials as the mating material without daring to use ceramics, making it practical. It turned out that it is possible to

The above test results are thought to be due to the following material properties.6 In other words, while the total wear amount when using normal tappet material (Fe12) is 19 μm, when using the 10 alloy, the total wear amount is 19 μm. The amount of wear is extremely high because
The main cause is the hardness of the tappet material. By the way, while the hardness of chilled Fe12 is 650 for ■] Sea 3°,
The above 10 alloys are only 90-110.

However, 10 alloy is used as a matrix, and AQ2 is added to this.
The hardness of FRM composited with 03 fibers and FRM composited with Af1203 fibers and the above carbon fibers is 130 for the former and 125 for the latter, which is not much higher than the hardness of only Af1 alloy. The reason for the low wear is that the AQ203 fibers contained in these FRMs have a very hard hardness of Hv2000 and are uniformly dispersed, making them excellent against Pa wear.

Furthermore, AQ20.FRM is a composite of AQ203 fiber and graphite carbon fiber. The AQ20. Fiber itself is very hard, and the fiber end exposed at the contact surface acts like a cutting tool and damages the other material, whereas graphitic carbon fiber has a weak bonding force in the C-axis direction and is lubricating itself. (self-lubricating property),
When these factors are combined, the aggressiveness is significantly reduced, and this effect becomes particularly large as the surface pressure increases. At an actual general surface pressure of approximately 70 kg/mu” between the camshaft and tappet,
Conventional materials suffer from even more wear, but when graphitic carbon fiber is combined, there is almost no change and wear is extremely low.

Based on the above basic test results, we conducted further experiments on various material combinations, fiber-reinforced materials, the amount of graphite carbon fiber mixed, etc.

This is where the present invention is made.

That is, the present invention provides a method for forming fiber-reinforced materials such as inorganic fibers, gold a-fibers, and whiskers, and metal materials such as hex alloys, Mg alloys, and the like as a matrix by a pressure forming method such as a die-casting method or a high-pressure casting method. In parts for engines, etc., the fiber reinforced material contains at least 1 to 5
The gist of the present invention is an FRM wear-resistant part containing graphitic carbon fiber, characterized in that it is a composite material containing vo Q% of graphitic carbon fiber.

The present invention will be explained in more detail below.

In the present invention, the matrix material may be a material that is used as a sliding member for engines, motors, and other machines, and is particularly preferably a light metal material such as 10 alloy, Mg alloy, etc., which reduces the weight of these materials.

Further, the fiber reinforced material may be one that has been tried for FRM, for example, SiC.

Inorganic fibers such as AQ, 03, B, Ni, W, Cu, F
e, metal fibers such as stainless steel, SiC, Si.

Examples include whiskers such as N4.

However, as the fiber reinforcing material to be composited, it is necessary to composite at least graphitic carbon fiber in a range of 1 to 5 vol% (ratio to the whole). 1 v
o If it is less than 2%, it is not effective, and if it is added in a large amount exceeding 5vo12%, no further lubricating effect can be obtained, which is not preferable because it will actually impair its own wear resistance.

Such FRM parts may be produced by conventional pressure forming methods such as die casting and high pressure casting. Applicable parts include, for example, tappets, bushing rods, rocker arm slippers, and valve caps, all or part of which are made into FRM.

(Example) The above-mentioned Ajl1 alloy was used as a matrix, and AQ20. Various parts made of a composite of 10 vol% fiber and 5 vol% graphitic carbon fiber were created by high-pressure casting.

Specifically, a preform of the above FRM material is created,
After preheating this to a temperature (approximately 800° C.) at which AQ can penetrate under pressure, it was set in a mold preheated to 250 to 300° C., and the molten AΩ alloy was high-pressure cast at a pressure of 40 to 200 MPa.

In addition, in this example, since such FRM members are used for wear resistance, in the case of a bushing rod, they are used only at both ends of the main body made of AQ alloy (Fig. 3), and in the case of a tappet, the main body made of AQ alloy is used. In the case of a rocker arm, it was used only on one end of the body made of AQ alloy (Fig. 5), and in the case of a valve cap, it was used on the entire body (Fig. 6).

When actual machine wear tests were conducted on these parts, results were obtained in which there was little wear on the FRM members themselves, and less wear on the mating material (steel material) as well.

(Effects of the Invention) As described in detail above, according to the present invention, at least an appropriate amount of graphitic carbon fiber is mixed and composited with the fiber reinforcing material in conventional FRM parts.
It is possible to significantly reduce the wear of the mating material while maintaining the wear resistance of the RM parts themselves, and it is possible to use ordinary steel materials as the mating material, making it possible to reduce weight and extend the lifespan of engines, motors, etc. by converting them to FRM. It is now possible to achieve this goal, and its effects are huge.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a comparison of the amount of wear between FRM parts made of various materials and mating materials, and Fig. 2 is an explanatory diagram showing the outline of the wear test. 3 to 6 are cross-sectional views showing examples in which the FRM members (shaded areas in each figure) obtained in the examples of the present invention are applied to all or part of various parts, and FIG. Figure 4 shows the case where it is applied to both ends of the bush rod, and Fig. 4 shows the case where it is applied to the lower part of the tappet. Figure 5 shows the case where it is applied to one end of the rocker arm.
FIG. 6 shows the case where it is applied to the entire valve cap. Patent Applicant Yanmar Diesel Co., Ltd. Representative Patent Attorney Takashi Nakamura Figure 1 Figure 3 Figure 5 RM Figure 4 OiFRM

Claims (1)

[Claims] In parts for engines etc. obtained by pressure forming methods such as die casting methods and high pressure casting methods, fiber-reinforced materials such as inorganic fibers, metal fibers, and whiskers and matrix materials such as Al alloys, Mg alloys, and other metal materials are used. An FRM wear part containing graphitic carbon fiber, characterized in that the fiber reinforcing material is a composite material containing at least 1 to 5 vol% of graphitic carbon fiber.