JPH0711358A - Aluminum matrix composite disk rotor - Google Patents

Abstract

PURPOSE:To attain the lightening of a disk rotor and to improve its friction performance at the time of braking and strength by casting-in the sliding face part of a composite material in which the content of aluminum or aluminum alloy matrix grains is reduced gradually from the surface layer to the inside with aluminum or an aluminum alloy. CONSTITUTION:For imparting friction properties to a sliding face and compatibility and fusibility with a disk rotor substrate to an internal layer, powdery mixtures obtd. by adding 20%Si-Al alloy powder to form a matrix with silicon carbide powder by 30, 15 and 5% respectively are successively laminated, and this laminate is compacted in a partially solidified temp. range into a sliding face part shape product having a ring shape. Furthermore, the layer side high in the content of silicon carbide is formed into the sliding face. Next, this sliding face part shape product 7 is set to a die 8 for squeeze casting, and the molten metal of an aluminum alloy 9 for casting is poured therein into a disk rotor in which the sliding face shape product 7 is cast-in with the aluminum alloy 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum-based composite disc rotor for use in a disc brake for relatively light loads, which is strongly demanded to be lightened in the fields of automobiles, railway vehicles, industrial machinery and the like.

[0002]

2. Description of the Related Art Since conventional disk rotors are made of cast iron, the specific gravity of the material itself is large and it is difficult to make the weight significantly smaller. On the other hand, a disk rotor made of a composite material in which aluminum or an aluminum alloy is used as a matrix has hitherto been disclosed in, for example, JP-A-59-1.
No. 73234 and Japanese Patent Application Laid-Open No. 2-142935, the composite material containing a large amount of reinforcing particles such as ceramics has poor toughness and machinability, while the content of the reinforcing particles is If the amount is small, the heat resistance and wear resistance are inferior, and none of them is sufficient for practical use.

[0003]

As a result of various studies in view of the above, the present invention has developed an aluminum-based composite disk rotor which is excellent in heat resistance and wear resistance and relatively excellent in toughness.

That is, the present invention is characterized in that a disk rotor made of aluminum or an aluminum alloy has a sliding surface portion made of a composite material in which the content of ceramic particles in the aluminum or aluminum alloy matrix is gradually decreased toward the inside. It is what

[0005]

The present invention uses the aluminum-based composite material in which aluminum or an aluminum alloy is reinforced with ceramic particles such as alumina or silicon carbide in the sliding surface portion of the disk rotor as described above. Moreover, the blending ratio of the ceramic particles on the surface layer side of the sliding surface portion is set to a relatively high value of 20 to 50%, and the blending ratio is gradually or continuously reduced toward the inside to reduce the sliding surface portion. Inside, the compounding ratio of the ceramic particles is about 2 to 10%.

With the disk rotor having such a structure, since the surface layer of the sliding surface portion has a high proportion of ceramic particles, it has excellent heat resistance and wear resistance, and the inside of the sliding surface portion has toughness and machinability. In addition, since the content ratio of the ceramic particles in this inner portion is lower than that in the surface layer side, the compatibility with the aluminum or aluminum alloy forming the portion other than the composite material is also excellent.

[0007]

EXAMPLES Next, examples of the present invention will be described.

First, 3% silicon carbide powder was added to each aluminum alloy powder having a composition of 20% Si-Al to form a matrix.
Three kinds of mixed powders (30% mixed powder, 15% mixed powder, 5% mixed powder) were prepared by mixing 0, 15, 5% and stirring. Next, in order to prepare the sliding surface portion of the disk rotor, as shown in FIG. 1, 30% mixed powder (2), 15% mixed powder (3), and 5% were mixed in the mold (1).
% Mixed powder (4) is added in this order from the bottom. The shape of the mold is such that the lower surface side of the 30% mixed powder initially charged is the surface layer side of the sliding surface portion.

The three layers of mixed powder charged in the mold (1) are pressure-molded by the upper punch (5) and the lower punch (6) in a semi-melting temperature region where a liquid phase is partially generated, and the mixture is pressed into a disk rotor. A ring-shaped sliding surface part product was obtained. The molding does not necessarily have to be a molding at a semi-melting temperature, and may be a hot molding. Next, as shown in FIG. 2, the sliding surface portion shaped product (7) is set in a molten metal forging die (8), and parts other than this sliding surface portion are made of casting aluminum alloy (AC4C) (9). In order to configure, the aluminum alloy (A
C4C) A composite material whose ceramic content decreases as the sliding surface portion goes inward from the surface layer by pouring the molten metal and casting the sliding surface shape product (7), and the other portion is an aluminum alloy A disc rotor made of was prepared. After that, unnecessary parts were removed and cutting was performed to finish the product.

In the present invention, the type of aluminum alloy powder or ceramic particles that form the matrix of the composite material, the mixing ratio of ceramics, the type of cast aluminum alloy,
The casting method and the like are not necessarily limited to the above, and it is desirable to select an appropriate one in consideration of the functions required for the product, cost, possessed equipment and the like.

[0011]

EFFECTS OF THE INVENTION According to the present invention, since the sliding surface portion has a relatively large amount of reinforcing particles such as ceramic particles on the surface side thereof, it is excellent in heat resistance and wear resistance, and the mixing ratio of particles becomes smaller toward the inside. Therefore, since it is made of an aluminum-based composite material that has good toughness and has good compatibility and fusion with the aluminum alloy that composes other than the sliding surface portion, it also functions as a disc rotor in terms of friction performance and strength during braking. It has remarkable effects such as being excellent.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a production example of a composite material according to the present invention.

FIG. 2 is an explanatory view showing an example of a method for manufacturing the disc rotor of the present invention.

[Explanation of symbols]

 1 Sliding surface molding die 2 30% mixed powder 3 15% mixed powder 4 5% mixed powder 5 Upper punch 6 Lower punch 7 Sliding surface shape product 8 Mold for molten metal forging 9 Aluminum alloy for casting

Claims (1)

[Claims] 1. A disk rotor made of aluminum or an aluminum alloy having a sliding surface portion made of a composite material in which the content of ceramic particles in an aluminum or aluminum alloy matrix is gradually decreased toward the inside. Base composite disc rotor.