JP2002005208A - Disc brake disc and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an Al-alloy disk brake and its manufacturing method, which has a sliding part made of a metal group composite material having excellent wear resistance, heat resistance and thermal crack resistance and can easily be machined. SOLUTION: A sliding part is made beforehand so as to have a necessary shape using a metal group composite material having excellent brake performance. This sliding part is put in a casting mold, and then molten Al-alloy is poured into the mold. Consequently, a brake disk, which is light, can bear a heavy load and can easily be machined in manufacturing, and its manufacturing method can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a high-speed, high-load brake disc used in railway vehicles, automobiles / motorcycles, aircraft, cargo handling vehicles, and the like.

[0002]

2. Description of the Related Art Disc brakes are often used as brakes for railway vehicles, automobiles / motorcycles, aircraft, cargo handling vehicles and the like. This disc brake is
Cast iron, low-alloy cast steel, and stainless steel are used as brake disc materials on the principle that braking force is obtained by friction between the brake disc and the brake shoe. In recent years, aluminum and its alloys, and aluminum-based composite materials have been used in some vehicles such as sports cars.

[0003] Aluminum alloy discs have a higher thermal conductivity than cast iron or forged steel, so that the generated frictional heat is quickly dissipated. It can be much lower. For this reason, the heat resistance and the heat crack resistance do not decrease so as to be inferred from the material strength, but since the wear resistance is low, it is difficult to apply the aluminum alloy as it is to a brake disk.

As a method for solving this difficulty, the invention of a brake member in which the outer surface of an aluminum alloy is coated with an iron alloy by plasma spraying or casting is disclosed in Japanese Patent Application Laid-Open No. 60-895.
No. 58 publication. However, in this case, there is a problem that peeling is likely to occur due to a difference in thermal expansion coefficient and a difference in elastic modulus between the coating material and the base material due to heat generated by repeated braking.

A method for improving the strength and wear resistance of an aluminum alloy itself is disclosed in JP-A-59-173.
No. 234 discloses a particulate or fibrous Al2O3, Si
An invention of a brake rotor disk in which C, Si3N4 and the like are dispersed has been proposed. Such a composite material has excellent strength and abrasion resistance, but has low toughness, and has extremely poor machinability.

Further, recently, as a lightweight composite brake disc and a method of manufacturing the same disclosed in Japanese Patent Application Laid-Open No. 9-53669, a surface material serving as a sliding surface is made of a composite material in which aluminum alloy particles or fibers are dispersed, and a base material is provided. As an aluminum alloy, a method in which a composite material and a base are metallically bonded has been invented. However, since the composite material is deteriorated in a specific manufacturing process, as a method for solving the problem, a method of pouring a molten aluminum alloy composite material serving as a sliding portion into a preheated base is disclosed in Japanese Patent Application Laid-Open No. H10-893.
No. 89 is presented. But even in this case,
The fluidity of the melt of the applied composite material is limited, and the volume content of ceramics is 5 to 5 from the viewpoint of workability after solidification.
Up to 40% by volume.

[0007] The composite material in the above-mentioned prior patent cannot increase the ceramic volume content due to restrictions due to the manufacturing method, so that a sliding member that can withstand a high load cannot be obtained.

[0008]

SUMMARY OF THE INVENTION The present invention is intended to reduce the weight of brake discs used in railway vehicles, automobiles / motorcycles, aircraft, cargo handling vehicles and the like, and has ceramics dispersed on the sliding surface. Provided is a method for more efficiently manufacturing a highly reliable disk having improved adhesion and machinability between an aluminum or aluminum alloy composite material and a substrate.

[0009]

SUMMARY OF THE INVENTION A lightweight composite structure in which a surface layer serving as a sliding surface is an aluminum alloy-based composite material, and a base material is an aluminum alloy, both of which are integrated by diffusion and mutual fusion. This is related to a method for manufacturing a brake disc, and is characterized in that a molded body made of a metal-based composite material previously molded using a ceramic preform is integrated by being cast with a molten aluminum alloy that is easy to machine. The manufacturing method of the lightweight composite structure brake disc described above.

The term "metal-based composite material" as used herein refers to a composite material formed by using a woven fabric using ceramic fibers as a base material and impregnating it with a molten aluminum alloy by die casting or molten metal forging. A composite material of a type in which particulate or fibrous ceramics are directly mixed into a molten metal and cast is a material having different properties and characteristics.

Therefore, the metal matrix composite material (hereinafter referred to as "molded body") as the sliding surface material used here may be either an integral type or a split type, but is previously molded and processed. It is assumed that

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a preform in which a ceramic fiber material such as heat-resistant alumina fiber, silicon carbide fiber, boron fiber or the like is laminated on a flat plate is prepared in advance as a molded body serving as a sliding surface of a brake disk. Then, a molten aluminum alloy is poured into and impregnated therewith to produce the alloy. As the impregnation method, there are various production methods for improving the adhesion between the preform and the base material, such as die casting and molten metal forging. As a result, about 40% or more of the volume content of the ceramic fibers in the molded body made of the metal-based composite material is obtained.

FIG. 1 shows an example of a sectional structure of a brake disk and wheels according to the present invention. A wheel 3 is provided with a disk 3 formed by casting a molded body 2 made of a metal matrix composite material.

The shape of the molded body 2 may be a donut-shaped plate-integrated type, but it is preferable to divide the molded body into a plurality of pieces for ease of manufacturing a preform. FIG. 2 shows an example of the arrangement of a plurality of molded bodies.

FIG. 3 shows an example of the arrangement of a molded body in the case of a split type brake disk as an example. The brake disc main body is fixed to the wheel by bolts 4 using bolts.

The production of the brake disc according to the invention is as follows:
The above-mentioned molded body serving as the sliding surface is placed in a mold, and an aluminum alloy serving as a base material is cast, and the molded body is cast. At that time, the molded body to be the sliding surface is uniformly and evenly arranged on both side surfaces of the disk, so that machining at the time of completion can be minimized. A casting method for casting a molded body may be a normal aluminum alloy casting method.

The aluminum alloy used as the base material is not limited as long as it has excellent high-temperature and normal-temperature strength among casting alloys specified by JIS, but an alloy whose strength can be improved by age hardening after casting, for example, , AC4C and AC8
A is desirable. It is not necessary to cast a composite material in which ceramic short fibers are dispersed as described in the above-mentioned prior patents.

[0018]

According to the present invention, the machinability which has been a difficulty in realizing the practical use of a disc brake having a lightweight composite structure instead of cast and forged steel as a disc brake for a high-speed, high-load vehicle is greatly improved. This has made it possible to manufacture brake discs with improved performance, and it has become possible to commercialize a high-performance lightweight disc brake in terms of manufacturing and cost.

[Brief description of the drawings]

FIG. 1 is a sectional view of a composite structure brake disc.

FIG. 2 is a plan view of a brake disk in which a molded body made of a metal-based composite material is disposed on a sliding portion.

FIG. 3 is a plan view and a sectional view of a split type brake disk.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wheel main body 2 Molded body 3 Brake disk 4 Bolt hole

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C22C 47/06 C22C 47/06 49/06 49/06

Claims (3)

[Claims] 1. A disc brake disc in which a sliding portion (molded body) made of an aluminum alloy-based composite material is integrated by casting with aluminum or an aluminum alloy. 2. A method for manufacturing a brake disk, in which a sliding portion (molded body) made of an aluminum alloy-based composite material is placed in a mold, and a molten aluminum or aluminum alloy which is easy to machine is poured into the mold and integrated. 3. The method according to claim 2, wherein the sliding portion (molded body) made of the aluminum alloy-based composite material is divided and manufactured.