JPH0341534B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a combination of two members that abut each other and slide relative to each other, and more specifically, one member is made of a composite material with silicon carbide whiskers as a reinforcement and an aluminum alloy as a matrix, and the other member is made of a composite material with silicon carbide whiskers as a reinforcement and an aluminum alloy as a matrix. This relates to a combination of two members, each of which is made of cast iron. Components and members of various machines are often required to have special mechanical properties. For example, in automobile engines, as demands for engine performance become higher, members such as pistons not only have excellent specific strength and rigidity, but also require that their sliding surfaces have excellent wear resistance. It has become a strong requirement to be present. As a means of improving the specific strength and abrasion resistance of such members, attempts have been made to construct them from composite materials made of various inorganic fibers as reinforcements and light metals such as aluminum alloys as a matrix. ing. As one such fiber-reinforced metal composite material,
Fiber-reinforced metal composite materials are already known in which the reinforcing material is silicon carbide whiskers, and the matrix is aluminum alloy. Abrasion resistance etc. can be improved. However, in a combination of two members that are in contact with each other and slide relative to each other, if one of the members is made of a fiber-reinforced metal composite material as described above, the material of the other member may As a result, the wear of the other member increases significantly, so that they cannot be used as a combination of sliding members that abut and slide relative to each other. The present inventors proposed a combination of two members that abut each other and slide relative to each other, one of which is made of a fiber-reinforced metal composite material and the other of which is made of cast iron. In order to minimize the amount of wear on both parts in a combination of parts, various experimental studies were conducted to find out what combination of materials and properties would be appropriate. As a result, they discovered that each must have specific characteristics. The present invention is based on the findings obtained as a result of the above-mentioned experimental research carried out by the inventors of the present invention, in which one member is made of silicon carbide whiskers with excellent strength and rigidity as a reinforcing material and an aluminum alloy is used as a matrix. A combination of two members made of fiber-reinforced metal composite material and the other member made of cast iron, which contact each other and slide relative to each other, and the sliding of both members relative to each other. The object is to provide a combination of two parts with improved surface wear resistance. According to the present invention, this object is achieved by combining a first member and a second member that are in contact with each other and sliding relative to each other, so that the sliding movement of the first member with respect to at least the second member is achieved. The face part is made of a composite material in which the total amount of non-fibrous particles with a diameter of 150μ or more is 1wt% or less, and the reinforcement is an aggregate of silicon carbide whiskers with a bulk density of 0.08g/cc or more, and an aluminum alloy is the matrix. This is achieved by a combination of members characterized in that at least the sliding surface portion of the second member relative to the first member is made of cast iron. According to the present invention, it is a combination of two members that are in contact with each other and slide relative to each other, and the sliding surfaces of both members relative to each other have excellent wear resistance. It is possible to obtain a combination of members in which the amount of wear on each sliding surface of the members can be minimized, and one of the members has excellent specific strength and rigidity. According to one detailed feature of the present invention, the bulk density of the silicon carbide whiskers as the reinforcing material is 0.08 g/cc due to the need to improve the strength and abrasion resistance of the fiber reinforced composite material constituting one member. , preferably 0.1 g/cc, more preferably 0.15 g/cc or more. According to another detailed feature of the invention, silicon carbide is very hard and, according to the results of experimental studies carried out by the inventors, particularly in diameter
If a composite material contains a large amount of non-fibrous particles of silicon carbide with a size of 150μ or more, it is extremely difficult to perform processing such as cutting on the composite material, and it may cause scuffing, etc. The total amount of non-fibrous silicon carbide particles with a diameter of 150μ or more is preferably 1wt% or less based on the total weight of the silicon carbide whisker aggregate.
It is limited to 0.7wt% or less. The combination of members according to the present invention may be applied to combinations of members of various mechanical devices, such as a cylinder and a piston of an automobile engine, a piston ring and a piston, and the like. DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention will now be described in detail by way of example embodiments with reference to the accompanying drawings. Example 1 A combination of two members that come into contact with each other and slide relative to each other, one of which is made of fiber-reinforced metal composite material and the other member is made of cast iron. A wear test was conducted to determine the appropriate material and properties of each member in the combination of members. Total amount of non-fibrous particles with a diameter of 150μ or less is 0.7wt%
The reinforcing material is a fiber molded body made of randomly oriented silicon carbide whiskers (manufactured by Tokai Carbon Co., Ltd.) with an average fiber diameter of 0.4μ and an average fiber length of 100μ at a bulk density of 0.35g/cc. After manufacturing a composite material with an alloy (JIS standard AC8A) as a matrix and applying T7 treatment to the composite material, the size of the composite material is 16 x 6 x 10 mm.
A block test piece was prepared using one surface (16 x 10 mm) as the test surface. Similarly, a block test piece of the same size made only of aluminum alloy (JIS standard AC8A), a block test piece of the same size made of a composite material with alumina-silica fiber as reinforcement and aluminum alloy as matrix, and alumina fiber were used. Block specimens of the same size were prepared from a composite material with an aluminum alloy as a reinforcement and a matrix. These block test pieces were sequentially set in the LFW friction and wear tester, and the mating parts, spheroidal graphite cast iron (JIS standard
FCD70) or low-alloy flake graphite cast iron.
A wear test was conducted by rotating the cylindrical test piece for 1 hour at a surface pressure of 20 Kg/mm ² and a sliding speed of 0.3 m/sec while supplying 5W-30). The combinations of block test pieces and cylindrical test pieces in this wear test were as shown in Table 1 below.

[Table] Figure 1 shows the results of the above wear test. The first
In the figure, the upper half represents the wear amount (wear scar depth μ) of the block test piece, and the lower half represents the wear amount (wear loss mg) of the mating cylindrical test piece. A to F correspond to test piece combinations A to F in Table 1 above, respectively. From FIG. 1, it can be seen that the block test piece (A) made only of aluminum alloy has a very large amount of wear, while the block test pieces (B to F) made of aluminum alloy reinforced with reinforcing fibers have a very large amount of wear. All test pieces are made of aluminum alloy only.
It can be seen that the amount of wear is very small compared to (A).
Regarding the wear of the cylindrical test pieces as the mating material, the wear amount of the cylindrical test pieces of combinations B, E, and F is as follows:
It can be seen that it is smaller than the combinations A, C, and D. In addition, a wear test similar to the wear test in this example was conducted when the matrix was made of aluminum alloy (JIS standard).
AC8B), aluminum alloy (JIS standard AC2B),
Tests were also conducted on block test pieces cut from composite materials formed in the same manner except that they were made of aluminum alloy (JIS standard AC4C), and test results substantially similar to those shown in Figure 1 were obtained. Ta. Example 2 From Example 1 above, in a combination of two members that are in contact with each other and slide relative to each other, if the other member is made of cast iron, regardless of the type of cast iron, First, it has been found that the reinforcing material of the composite material constituting one of the members is preferably silicon carbide whiskers, so what is the appropriate value for the bulk density of the silicon carbide whiskers as the reinforcing material? A wear test was conducted on the Total amount of non-fibrous particles with a diameter of 150μ or less is 0.7wt%
Silicon carbide whiskers (manufactured by Tokai Carbon Co., Ltd.) with an average fiber diameter of 0.4μ and an average fiber length of 100μ that have been treated to have a bulk density of 0.04, 0.07, 0.11, 0.16,
The reinforcing material is a fiber molded body randomly oriented at 0.35 and 1.2 g/cc, and aluminum alloy (JIS standard
AC8A) as a matrix was produced using a high-pressure casting method (pressing force 1000 Kg/cm ² , molten metal temperature 700°C), and after each composite material was subjected to T7 heat treatment, the size was smaller than that of each composite material. is 16×6
Block test pieces G ₁ to _{G 6} were prepared, each having a size of 10 mm x 10 mm and one surface (16 x 10 mm) serving as the test surface. In addition, as a comparative example, aluminum alloy (JIS standard
Block test piece of the same size made only of AC8A)
Created G ₀ . These test pieces were sequentially set in the LFW friction and wear tester, and the mating parts, which were 35 mm in outer diameter, 30 mm in inner diameter,
Contact the outer circumferential surface of a cylindrical test piece made of spheroidal graphite cast iron (JIS standard FCD70) with a width of 10 mm, and apply room temperature lubricating oil (castle motor oil) to the contact area of the test piece.
5W−30) while supplying surface pressure of 20Kg/mm ² and sliding speed.
A wear test was conducted by rotating a cylindrical specimen for 1 hour at 0.3 m/sec. The results of this wear test are shown in FIG. In Figure 2, the upper half represents the wear amount (wear scar depth μ) of the block test piece, and the lower half represents the wear amount (wear loss mg) of the cylindrical test piece, which is the mating material. The horizontal axis represents the bulk density of the silicon carbide whiskers, and symbols G ₀ to G ₆ correspond to the above-mentioned block test pieces G ₀ to _{G 6} , respectively. From this Fig. 2, in terms of the wear amount of both the block test piece and the cylindrical test piece, the bulk density of the silicon carbide whisker is 0.08 g/cc or more, preferably 0.1 g/cc.
It can be seen that it is desirable that it be at least 0.15 g/cc, more preferably at least 0.15 g/cc. The same abrasion test as this one was also conducted on a block specimen made from a composite material reinforced with silicon carbide whiskers (average fiber diameter 0.2μ, average fiber length 30μ) manufactured by Tateho Chemical Industry Co., Ltd. However, results similar to those shown in FIG. 2 were obtained. From the results of the above-mentioned examples, it was found that the combination of two members that come into contact with each other and slide relative to each other, one of which is made of a composite material with silicon carbide whiskers as a reinforcement and an aluminum alloy as a matrix, In the case of a combination of two parts, such as one made of cast iron and the other made of cast iron,
The composite material that makes up one of the members has a diameter of 150μ.
It is preferable that the composite material is a composite material in which the total amount of non-fibrous particles is 1 wt% or less and the bulk density is 0.08 g/cc or more, using silicon carbide whiskers as a reinforcing material and an aluminum alloy as a matrix. It can be seen that the cast iron constituting the member is preferably spheroidal graphite cast iron or flake graphite cast iron. Although the present invention has been described in detail with respect to specific embodiments above, the present invention is not limited to such embodiments, and it is understood that various embodiments are possible within the scope of the present invention. It will be clear to those skilled in the art.

[Brief explanation of the drawing]

Fig. 1 is a graph showing the results of the wear test of Example 1 conducted on various combinations of fiber-reinforced composite materials and cast iron, and Fig. 2 is a graph showing the results of the wear test conducted using the bulk density of silicon carbide whiskers as a parameter. 2 is a graph showing the results of the wear test No. 2.

Claims (1)

[Claims] 1 A combination of a first member and a second member that are in contact with each other and slide relative to each other, and at least the sliding surface of the first member relative to the second member is made of non-fibrous material with a diameter of 150μ or more. The second member is made of a composite material in which the reinforcing material is an aggregate of silicon carbide whiskers having a total amount of particles of 1 wt% or less and a bulk density of 0.08 g/cc or more, and an aluminum alloy as a matrix. A combination of members, characterized in that at least the sliding surface portion for the first member is made of cast iron.