JPH0420973B2 - - Google Patents

Description

[Detailed description of the invention]

A. Object of the Invention (1) Field of Industrial Application The present invention relates to a fiber-reinforced composite member for engines, which is made by filling and composite inorganic fibers into the matrix metal of members such as engine pistons and cylinder sleeves. (2) Prior Art Conventionally, each fiber-reinforced composite part of the above-mentioned fiber-reinforced composite member has been given similar characteristics. (3) Problems to be solved by the invention However, in fiber-reinforced composite parts for engines, the required properties of the fiber-reinforced composite parts differ from each other in various parts of the composite parts. The head section and ring land section, which are subjected to high loads, are required to have sufficient mechanical strength and heat resistance, while the skirt section, which constantly rubs against the cylinder, has particularly good sliding properties with the cylinder and good wear resistance. is required. However, as mentioned above, imparting different characteristics to each location of the fiber-reinforced composite part is
This is completely impossible with conventional fiber-reinforced composite materials that use only fibers of the same material for each product, and it is difficult to achieve this even if the orientation or amount of encapsulation of some of the fibers is changed. . The present invention has been proposed in view of the above, and an object of the present invention is to provide a fiber-reinforced composite member for an engine with a simple structure, which includes a plurality of fiber-reinforced composite parts having different required characteristics. B. Structure of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention provides a fiber-reinforced composite member for an engine comprising a plurality of fiber-reinforced composite parts having different required characteristics. , a plurality of inorganic fiber molded bodies selected to have different materials in accordance with the required characteristics of the plurality of fiber-reinforced composite parts are respectively disposed in correspondence with the plurality of fiber-reinforced composite parts. , these fiber molded bodies are filled and composited with the same matrix metal. (2) Effect By simply selecting different materials for the individual fiber molded bodies corresponding to the plurality of fiber-reinforced composite parts in the above-mentioned member, the characteristics of the plurality of fiber-reinforced composite parts can be made completely different. Therefore, it is possible to very easily and accurately impart optimum properties to each fiber-reinforced composite part of the above-mentioned member in accordance with the intended function of each composite part. During manufacturing, the characteristics of each part of the composite part can be easily changed by simply setting a plurality of fiber molded bodies made of different materials in a mold. (3) Embodiment An embodiment of the present invention will be described below with reference to the drawings. An engine piston P whose matrix is made of an Al-Si alloy such as Roex (AC8B)
The head part 1, the ring land part 2 connected to the lower part of the outer periphery of the head part 1, and the ring land part 2
A ring groove 2a is formed on the outer circumferential surface of the ring land portion 2, into which a piston ring (not shown) is mounted. In the matrix 6 of the piston P, a first fiber molded body 4 is filled in the head portion 1 and ring land portion 2, and a second fiber molded body 5 is filled in the skirt portion 3 by a high-pressure solidification casting method. A piston P is provided corresponding to the first and second fiber molded bodies 4 and 5, respectively.
First and second fiber-reinforced composite parts F 1 and F 2 are formed in the first and second fiber-reinforced composite parts F ₁ and F ₂ . The first fiber molded body 4 maintains the strength of the head portion 1 and the ring land portion 2 that are exposed to high temperatures and high loads, and suppresses thermal expansion, and also prevents blow-through of the head portion 1, settling of the ring groove 2a, etc. In order to prevent this, the crystallized glass fibers are formed into a flat plate shape from intertwined crystallized glass fibers, and the bulk density is adjusted to 0.4 g/cm ³ before filling and compounding into a matrix. In addition, the second fiber molded body 5 suppresses the thermal expansion of the skirt portion 3 that slides against the cylinder, improves its wear resistance and scuffing resistance, and furthermore, takes into account sliding properties with the cylinder, and is designed to It is formed into a thin cylindrical shape from the carbon fibers intertwined with each other, and the bulk density is 0.3 g/cm ³ before filling and compounding into the matrix.
has been adjusted to. The initial dimensions of each of the fiber molded bodies 4 and 5 take into account the compression rate due to the bulk density. When the piston P is cast by the high-pressure solidification casting method, the first and second fiber molded bodies 4 and 5 are set in a casting mold corresponding to the external shape of the piston P, and then the molten metal is poured. Then, the molten metal is solidified while applying a hydrostatic high pressure of 50 to 2000 kg/cm ² using a pressure punch, thereby obtaining a piston P as shown in FIG. The piston P obtained in this manner has excellent strength and heat resistance, especially in the head portion 1 and the ring land portion 2, and is effective in preventing the blow-through of the head portion 1 and the settling of the ring groove 2a. It was confirmed that in part 3, thermal expansion was effectively suppressed, wear resistance and scuffing resistance were improved, and slidability with the cylinder was also good. Furthermore, when the boundary of the composite part of the piston was heated with a burner, the part containing only Roex completely melted, but the composite part completely maintained its original shape, and an improvement in heat resistance was observed. In the above embodiment, Al-
Although a Si-based alloy is shown, cast iron, copper, aluminum, magnesium, or an alloy thereof may be used in the present invention. Furthermore, even if Silumin (AC4A material) or hypereutectic silicon alloy is used as a matrix, there is no problem in filling and compounding, and the same physical results can be obtained. By the way, Fig. 2 1 shows the relationship between molten metal pressure and pressurization time in the filling and compounding process when a fiber molded body made of intertwined inorganic fibers is filled and compounded into a matrix metal by high-pressure solidification casting. A fiber molded body formed into a certain shape from intertwined inorganic fibers with a capacity of 38.5 cm ³ and a bulk density of 0.3 g/cm ³ was used, and an aluminum alloy (Japanese Industrial Standards, AC8B material) was used for the matrix, and cast. This is the case when casting was performed at a temperature of 780°C. 2 is the molten metal pressure when there is no fiber molded body.
The relationship between pressurization time is shown. A indicates a filling region, B indicates a composite pressure region, C indicates a squeeze solidification region, and D indicates a coagulation region. As is clear from Fig. 2, in region A, the static pressure applied to the molten metal due to the compression of the fiber molded body and the infiltration of the molten metal increases more slowly than in region 2, and therefore the molten metal is not in a completely molten state. Filled into a fiber molded body. After that, static pressure is rapidly applied in the B region, squeeze solidification is performed in the C region, and solidification is completed in a short time in the D region, making it possible to achieve extremely good compositing, and to achieve rapid solidification under high pressure. Therefore, the degree of adhesion and compositing between the fibers and the matrix is high, and at the same time, the matrix itself is significantly strengthened. FIG. 3 shows the relationship between bulk density and compressibility of the fiber molded bodies shown in Tables (3) to (6) below. Initial dimensions of fiber molded body…70mm diameter, 10mm thickness Matrix…aluminum alloy (Japanese Industrial Standard AC8B material) Static pressure…2000Kg/cm ^2Pouring temperature…780℃

【table】

[Table] Figure 4 shows the bulk density of the fiber molded bodies of (3) to (6) above.
The relationship between the filling rate after compounding is shown. As is clear from FIG. 3, the fibers with lower bulk density are more compressed than the initial dimensions, and the fiber filling ratio after composite is almost the same. Therefore, for the same bulk density of the fiber molded body, only the amount of molten metal and the mold stroke change in terms of initial dimensions and capacity, which have relatively little effect on composite formation. Further, even with long fibers, there is no problem with the infiltration of the molten metal, and coagulation starts immediately after the molten metal enters and fills the fiber molded body, so the fibers are not broken or deformed by the pressure applied during the coagulation process.
Therefore, the fibers used in the present invention are preferably long fibers in consideration of composite reinforcement and fiber entanglement during production of a fiber molded article since there are no manufacturing restrictions. In addition, as shown in Figures 3 and 4, fibers (including whiskers) can be used to prevent molten metal from penetrating and compounding when using fibers that have a metal coating layer of copper, nickel, silver, etc. on the fiber surface or a diffusion layer on the fiber surface. In this case, solid solution of the metal film layer and diffusion layer with the matrix,
Since the diffusion phenomenon occurs, the wettability of the fiber molded body to the matrix is improved, and as a result, the compressive force of the fiber molded body is small, and it is possible to compound the fiber molded body to one with a higher bulk density. The limit condition for compounding in the above filling compounding process is that the molten metal infiltration resistance increases before or during full filling,
It is determined when the static pressure of the molten metal starts to rise, and as shown in Figure 4, the bulk density of the fiber molded body becomes the dominant factor, and the upper limit of the bulk density is 0.6 g/cm ³
If the upper limit is exceeded, the buffering function of the fiber molded body against the molten metal filling pressure decreases, and the molten metal pressure rises rapidly in the molten metal filling area, causing the molten metal to solidify before it is densely filled into the fiber molded body. , good compositing cannot be obtained. In addition, the melting point of the matrix,
The heat capacity, solidification range, heat of solidification, heat capacity and thermal conductivity of the fiber molded body also have a considerable influence. In addition, the bulk density of the fiber molded body was set to 0.6 as described above.
g/cm ³ or less, and if a high-pressure solidification casting method is used as a composite means for filling the matrix of the molded body, the molten metal will infiltrate the fiber molded body in a completely molten state as described above, and then rapidly solidify. So,
It has the advantage of not being subject to matrix constraints. In other words, taking the aluminum alloy described below as an example, even a 23% hypereutectic silicon alloy that crystallizes a large amount of hard primary crystals, which is difficult to do using conventional methods, can be filled and composited without any problems. There is no possibility of breaking the fibers. Furthermore, during the production of the fiber molded article, it is possible to two-dimensionally orient the fibers and entangle them with each other, and this orientation is maintained even after compositing, which is effective in improving the bending strength. C. Effects of the Invention As described above, the present invention provides a fiber-reinforced composite member for an engine, which includes a plurality of fiber-reinforced composite portions having different required characteristics, and wherein the required characteristics of each of the plurality of fiber-reinforced composite portions are different from each other. Correspondingly, a plurality of inorganic fiber molded bodies selected to have different materials are disposed corresponding to the plurality of fiber-reinforced composite parts, respectively, and the same matrix metal is filled into these fiber molded bodies to form a composite part. Therefore, by simply selecting different materials for the individual fiber molded bodies corresponding to the plurality of fiber-reinforced composite parts in the above-mentioned member, the characteristics of the plurality of fiber-reinforced composite parts can be made completely different. Therefore, it is possible to very easily and accurately impart optimal properties to each fiber-reinforced composite part of the above-mentioned component in accordance with the intended function of each composite part, so completely different properties can be imparted. It is also possible to manufacture composite members that have multiple fiber-reinforced composite parts, such as a first composite part with excellent mechanical strength and heat resistance, and a second composite part with excellent sliding properties and wear resistance. possible, and a fiber-reinforced composite member of extremely high quality as a whole can be obtained. Moreover, during manufacturing, the characteristics of each part of the composite part can be easily changed by simply placing multiple fiber molded bodies of different materials in a mold, which simplifies the work process and improves productivity. can contribute.

[Brief explanation of drawings]

Fig. 1 is a vertical cross-sectional view of a piston to which the present invention is applied, Fig. 2 is a pressure time-molten metal pressure relationship diagram, Fig. 3 is a fiber molded product bulk density-compressibility relationship diagram, and Fig. 4 is a fiber molding diagram. FIG. 3 is a diagram showing the relationship between body bulk density and filling rate after compounding. _F1 ...First fiber-reinforced composite part, _F2 ...Second fiber-reinforced composite part, P...Piston as a fiber-reinforced composite member, 4...First fiber molded body, 5...Second fiber molded body, 6...matrix.

Claims (1)

[Scope of Claims] 1. A fiber-reinforced composite member for an engine comprising a plurality of fiber-reinforced composite portions having different required characteristics, wherein the material is selected in accordance with the required characteristics of each of the plurality of fiber-reinforced composite portions. a plurality of inorganic fiber molded bodies selected such that they are different from each other are arranged corresponding to the plurality of fiber-reinforced composite parts, respectively,
A fiber-reinforced composite member for an engine, characterized in that these fiber molded bodies are filled and composited with the same matrix metal. 2 The fiber-reinforced composite member is a piston whose matrix metal is an Al-Si alloy, with a glass fiber molded body corresponding to the head portion and ring land portion, and a carbon fiber molded body corresponding to the skirt portion. The fiber-reinforced composite member for an engine according to claim 1, wherein the fiber-reinforced composite member for an engine is provided with: