JPH109297A - Brake caliper and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To distribute the composition of a caliper effectively and satisfy a strength and processing property simultaneously by molding and harmonizing and combining integrally a cylinder part by a matrix metal impregnated in a yoke part form. SOLUTION: In a yoke part in which rigidity is required, the yoke part form 20 is made by molding a seramics material like a seramic fiber, a whisker and a particle. Meanwhile, in a cylinder part, the form 22 of a real size is made by a high temperature burnt down material of a styrol foam and jointed integrally with the yoke part form 20 so as to make a caliper form 24. At this time, a projection 23 formed on a bridge part 10 is inserted and combined strongly to a recessed groove 25 formed in the other cylinder part side. A metal matrix is formed to the inside of a die forming the outer periphery of this form 24 by a metal cover material 26 and by impregnating aluminium metal or its alloy into the gap in the form 20 and also a metal mass is formed by filling a melted metal in the gap burning a styrol foam by a high temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake caliper and a method for manufacturing the same, and more particularly to a brake caliper, which effectively distributes the composition of the caliper as a strength member of a disc brake.
The present invention relates to a brake caliper capable of simultaneously satisfying both strength and workability, and a method for manufacturing the same.

[0002]

2. Description of the Related Art In a disk brake, a caliper is mounted on a fixed support via a support mechanism including a guide pin so as to be movable in the axial direction of a disk rotor. Hydraulic means is attached to the caliper so that the friction pad can be pressed against the rotor, and by operating the hydraulic means, the piston of the hydraulic means presses one friction pad against the rotor and reacts Then, the other friction pad is pressed against the rotor by the caliper claw portion.
Since a large stress is generated in such a caliper due to a braking action, sufficient caliper is required, and a demand for weight reduction is high.

[0003] From such a viewpoint, a caliper is manufactured from aluminum or an aluminum alloy. However, because of its low rigidity, a reinforced composite in which a ceramic material such as alumina or silicon carbide is mixed into molten aluminum is used. There is an example of manufacturing using materials. However, due to the difference in the specific gravity of the ceramic material mixed with the aluminum base material, it is not possible to disperse the reinforcing material evenly in the molten aluminum, and the reinforcing material distribution of the manufactured product becomes uneven, However, there was a drawback that uniformity was not obtained.

[0004] For this reason, a preform is formed from the reinforcing material so that the reinforcing material can be uniformly dispersed.
There has been proposed a method in which a metal is impregnated with the metal to form the metal. Japanese Patent Application Laid-Open No. 6-159405 discloses that a caliper is manufactured from a material obtained by combining ceramic particles based on aluminum or an alloy thereof. This has a structure in which the volume content of ceramic particles is changed by separately providing a bridge portion requiring high strength and another cylinder portion which does not require relatively high strength.

[0005]

However, when a brake caliper is formed from an aluminum composite material by a conventional method, the composite material is inferior in machinability, so that it is particularly necessary to form a cylinder hole or a guide pin insertion hole. This is extremely difficult, and therefore, the cutting tool wears quickly in the composite material portion for drilling and tapping, which has been a bottleneck in mass production. In addition, in the method described in the above publication, the cutting work is not considered at all, and the bridge part and the cylinder part are formed separately, and the caliper is used to process the mating surface of the two parts. In addition to these processes for fastening bolts, it is necessary to integrate these components by bolting them together, so that many parts are required for assembling, and the number of assembling steps is increased.

The present invention focuses on the above-mentioned conventional problems, and the yoke portion, which requires high strength, has a high rigidity structure, and the cylinder portion is made of a base metal mainly having workability so as to distribute strength. It is an object of the present invention to provide a brake caliper and a method of manufacturing the brake caliper, which can have any structure according to the caliper function, and which are integrally formed without separate molding.

[0007]

To achieve the above object, a brake caliper according to the present invention is a brake caliper comprising a yoke portion and a cylinder portion, wherein the yoke portion has ceramic fibers, whiskers, particles and the like. A foam molded substantially in actual size from the ceramic material is embedded therein, and the cylinder portion is molded from the same metal as the matrix metal impregnated in the yoke portion foam, and the cylinder portion is formed via the metal base in the yoke portion foam. The present invention is characterized in that metals are integrally integrated with each other.

In the method for manufacturing a brake caliper according to the present invention, first, a ceramic foam is formed in accordance with the shape of a portion requiring strength of the brake caliper, and the other portions are formed of a high-temperature burnable material such as styrene foam. After these are joined and integrated, a space cavity is formed by burning out the styrofoam portion at a high temperature, and impregnated and filled with a molten metal to integrally form the metal mass through the metal group in the foam. It is characterized by being integrated by fusion.

More specifically, the caliper yoke portion is formed of a ceramic material such as ceramic fibers, whiskers, particles, or the like to a substantially exact size, and the cylinder portion foam is formed of a high-temperature burnable material. Is formed, and the outer surface of the caliper foam is covered with a shielding material, and the aluminum or an alloy thereof serving as a caliper base material is filled in the caliper foam under heating to thereby form the ceramic in the cylinder foam and the yoke ceramic. The caliper is manufactured by impregnating in the voids of the foam.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of a brake caliper and a method of manufacturing the same according to the present invention will be described in detail with reference to the drawings.

The caliper configuration can be roughly classified as shown in FIGS.
As shown in FIG. 3, a yoke portion 14 including a bridge portion 10 and a caliper claw portion 12, a caliper arm portion 16 serving as a sliding support mechanism with a fixed support and a guide pin, and constituting a hydraulic means. And a cylinder section 18 into which a pressure piston is incorporated. The yoke portion 14 is required to have high rigidity because it is subjected to a spreading action in the axial direction of the rotor by the braking operation or directly receives the braking force from the friction pad, while the cylinder portion 18 is subjected to drilling or the like. Therefore, good cutting workability is required.

According to the present invention, a metal matrix composite in which a yoke portion 14 is made of a ceramic material as a reinforcing material impregnated with a metal (Metal Matrix Composite).
es: MMC) and one of the cylinder portions 18
Is based on the knowledge that the functions required for each can be satisfied by being configured as a metal mass made of a material metal. Then, the matrix metal constituting the metal matrix composite and the metal material of the cylinder portion metal mass are made identical so that the yoke portion 14 and the cylinder portion 18 are integrally formed, and the two members have an integrally joined structure. It is based on the knowledge that it can be formed into a shape.

For this reason, as shown in FIG. 1, a yoke part 14 requiring rigidity is mixed and dispersed in a ceramic material using a binder, put into a mold, and pressed to form a yoke part foam 20. The foam ceramic material is used as a reinforcing material.

On the other hand, the cylinder part 18 is also made of a foam 22 or the like by using a high-temperature burnt material to form the foam 22 in the actual size. This is joined to the yoke part form 20 to form a caliper form 24 (FIG. 1).
(2)). At this time, by joining the yoke part foam 20 and the cylinder part foam 22 with a fitting structure, the jointability is improved and the strength of the manufactured caliper can be ensured. As shown in FIG. 3, the protrusions 23 are formed on the inner left and right inner peripheral portions of the bridge portion 10 and the concave grooves 25 are formed on the cylinder portion 18 side so that they are fitted and connected. I have.

A caliper foam 24 made of a joined body of ceramic foam and styrofoam foam.
Is covered with a metal shielding material 26 to form a so-called mold, the inside of which is filled with aluminum metal or an alloy thereof, and the molten metal is impregnated into voids in the yoke foam 20 to form a metal matrix. In addition, the styrofoam is burned off by high temperature, and the burnt-out space is filled with a molten metal to form a metal mass.

Here, when impregnating the voids of the yoke foam 22 with metal, the surface tension of the metal is a factor of impairment of impregnation. Therefore, centrifugal or press-in may be performed. It is desirable to coat the material surface with magnesium nitride so as to reduce the surface tension of the molten metal. For this reason, the yoke part form 22
About 1% by weight of magnesium metal is mixed in the raw material, and the operation may be performed in a nitrogen atmosphere at the time of impregnation of molten aluminum. Of course, it is also possible to adopt a technique such as CVD coating of the surface of the ceramic particles or fibers of the yoke part form 22 with magnesium nitride.

Hereinafter, a method of manufacturing the brake caliper of the present invention will be described based on a specific manufacturing method with reference to FIG.

(A) Yoke Portion Form Forming Step A foam corresponding to the yoke portion is prepared using a ceramic material. Alumina (A
One or more known materials such as l ₂ O ₃ ) and silicon carbide (SiC) may be used. This ceramic material may be in any form of fibers, whiskers, particles or the like, but it is desirable to use particles from the viewpoint of moldability. Therefore, for example, alumina powder is used as a reinforcing material, supplied to a mixer, mixed with a binder and dispersed, and then foam-formed in a real size by a molding machine to have a yoke shape.

As the binder, sodium silicate, aluminum phosphate, colloidal silica or the like may be used. At this time,
By appropriately selecting the particle size of the ceramic material,
The porosity can be arbitrarily adjusted, and the volume content of the ceramic material can be adjusted. If the volume content is large, the rigidity is increased, but if it is subjected to repeated stress as in a caliper, it is necessary to have high toughness. Therefore, it is effective that the yoke foam has a volume content of 10 to 60%.

In forming the foam, a ceramic material in which a binder is dispersed is put into a mold having a cavity corresponding to the shape of a yoke, and is first compacted at room temperature. Then, as will be described in a later step, gradually 10
Heat to 0 to 400 ° C. to make a yoke foam. This heating temperature may be a temperature at which the binder is burned off,
Generally, about 150 ° C. is desirable. That is, the mixture of the ceramic material and the binder is heated to a temperature at which the mixture of the ceramic material and the binder is bonded and bonded in a powder state, and the foam is maintained at the actual size.

(B) Cylinder Portion Form Forming Step The cylinder portion is formed using a material which is burned off at a high temperature, such as styrene foam. That is, a foaming material is filled in a mold having a cavity corresponding to a cylinder portion by a foaming molding machine to form a polystyrene foam having the same shape as the cylinder portion. The form of the cylinder part foam combined with the yoke part form is set so as to form the same form as the desired brake caliper.

(C) Step of forming caliper body preform The cylinder portion is formed so that the combined joining of the cylinder portion foam and the yoke portion foam is performed well, and furthermore, the fusion bonding of the metals is performed well. A concave groove 25 is formed in the foam 22, while the yoke portion foam 2 is formed.
A projection 23 conforming to this is formed at 0 and fitted and coupled. As shown in the molded caliper body of FIG. 3, flange protrusions are formed on the left and right sides on the bridge inner side of the yoke part foam, and grooves for receiving the flange projections are formed on the left and right sides of the cylinder part foam. These are to be fitted. These joining surfaces may be joined by a binder.

(D) Application Step of Metal Shielding Material The yoke portion and the cylinder portion are combined, and the metal shielding material is applied to the outer peripheral portion by a shielding material application device to form a coating layer. This metal shielding material has impermeability to molten aluminum when filling and impregnating aluminum in a later step, but it is sufficient to secure air permeability, and fine flake graphite is converted into a slurry or paste using a slurry agent. What is necessary is just to apply | coat to a surface and to dry this, and to form a shielding film type | mold.

(E) Caliper Body Forming Step The caliper in which the yoke and the cylinder are combined is heated in a furnace to burn out the binder in the yoke and burn out the styrene foam in the cylinder. This is because after applying the metal shielding material, the caliper body foam at room temperature is put into a drying furnace, and gradually heated to 400 ° C. in the drying furnace, whereby the binder in the yoke part foam 20 and the cylinder part foam are formed. Styrofoam constituting 22 is burned off. In the formed caliper body type, the ceramic foam remains on the yoke part foam 20, and the cylinder part becomes a hollow cavity.

(F) Metal Impregnation Step Thereafter, the caliper body mold is mounted and fixed on a mold holding member, and is filled with a nitrogen gas atmosphere.
The melting temperature of aluminum as a base metal is about 750
It is put into an impregnating furnace which has been heated to about 850 ° C., but is first passed through a preheating furnace in order to prevent cracks from occurring due to thermal shock of the yoke foam 20. Therefore, in the preheating furnace, since the temperature is raised to about 400 ° C. in the drying furnace, the heating is performed gradually from 400 ° C. For the caliper body type, the aluminum alloy is poured on the way from the preheating furnace to the impregnation furnace to fill the cylinder part, and in consideration of infiltrating the aluminum alloy into the preform of the yoke part, the yoke part foam The arrangement of the caliper body type is set so that the metal shielding material on the side is exposed to the furnace atmosphere.

In the impregnation furnace 42, nitrogen gas passes through the metal shielding material and penetrates into the yoke foam 20, and chemically bonds with the magnesium metal in the foam to form magnesium nitride, which is an aluminum alloy to ceramic material. Improves wettability. As a result, the yoke part form 20
On the other hand, the molten aluminum alloy penetrates into the voids in the yoke foam by capillary action, forming a so-called matrix metal. On the other hand, the cylinder portion is filled with the molten aluminum alloy as it is, and the portion becomes a so-called metal mass state and is formed in the same cavity shape. The aluminum alloy in the yoke foam is impregnated and treated in the impregnation furnace until the outer surface reaches the interface with the metal shielding material.

(G) Cooling Finishing Step The molded product discharged from the impregnation furnace is then supplied to a cooling device for performing a cooling treatment until the metal base material is solidified. Here, the metal is cooled to room temperature, and as shown in FIG. 5, the yoke portion has a metal-based ceramic structure with the ceramic foam embedded therein (the lower half portion in FIG. 5), and the cylinder portion has the same metal mass structure. (Upper half of the figure). The metal that has penetrated into the gap between the ceramics in the yoke portion is a matrix metal base having a so-called mesh-like metal arrangement, and has a structure in which the metal mass in the cylinder portion is fusion-bonded at their boundary surface. The caliper in the fitting portion between the yoke portion and the cylinder portion of the caliper body thus formed is maintained strong because the yoke portion is fitted to the cylinder side by forming a convex portion.

The caliper prepared as described above is then subjected to a treatment for removing a metal shielding material on the outer surface, and the surface of the molded product is subjected to surface treatment by sandblasting. Assembled as

In the caliper, the yoke portion having a high stress has a high Young's modulus, good rigidity, and can be reduced in weight.

Further, since the cutting portion is a matrix aluminum alloy, conventional machining equipment and cutting tools can be used, and an inexpensive caliper can be provided.

In the above-described method, the method of forming the caliper separately from the yoke portion 14 and the cylinder portion 18 has been described. However, as shown in FIGS. 6 to 8, the method is also used as a partial reinforcement of the caliper. be able to. FIG. 6 is intended to reinforce only the left and right side edges of the caliper. This is to form a preform corresponding to the reinforcing portion 30 and the other portions are formed of styrofoam. Then, the styrene foam and the binder are burned off, and the aluminum alloy is impregnated into the ceramic foam of the reinforcing portion, and at the same time, the styrofoam portion is burned off, and the metal mass structure may be formed by using an aluminum alloy as the same metal.

FIG. 7 shows an arrangement in which a plurality of reinforcing material block foams 32 are arranged along a line parallel to the rotor axis extending from the caliper claw to the cylinder portion via the bridge from the caliper claw. 8 shows a case in which almost all of the calipers are used as a reinforcing material, and a portion corresponding to the reinforcing block in FIG. In any case, a part of an arbitrary product is formed of ceramic foam, the other part is formed of styrene foam, and these are integrally joined and heated in a mold. By burning out the binder and styrene foam part, and then impregnating and filling the molten metal,
By arranging the reinforcing portion at an arbitrary position and achieving fusion bonding with other metal groups, an effect of increasing the rigidity of only the portion where the strength of the product is required can be obtained.

[0033]

As described above, the present invention relates to a method for manufacturing a brake caliper, in which a caliper yoke portion is formed into a foam with a ceramic material such as ceramic fibers, whiskers, particles, etc. to a substantially actual size, and a cylinder is formed by a high temperature burnout material. The caliper foam is formed by forming a caliper foam, joining and integrating them to form a caliper foam, covering the outer surface of the caliper foam with a shielding material, and heating the aluminum or its alloy as a caliper base under heating. The caliper is manufactured by impregnating the inside of the cylinder foam and the gap of the yoke ceramic foam by filling the inside of the cylinder foam. Foam is embedded and impregnated in this yoke foam The cylinder part is molded from the same metal as the matrix metal, and the cylinder part metal is integrated and fused together via the metal base in the yoke part form. High, brake performance can be improved, and the parts that require cutting, such as the cylinder part, are made of metal mass, so processing in this part is easily performed, and the wear of the cutting tool is small, An excellent effect that rigidity and workability can be secured at the same time is obtained.

[Brief description of the drawings]

FIG. 1 shows the formation of a foam during the production process of a brake caliper,
It is explanatory drawing of the joining and the coating process of a metal shielding material.

FIG. 2 is a plan view of the manufactured caliper.

FIG. 3 is a partial cross-sectional view of the caliper.

FIG. 4 is a process chart of a manufacturing method according to the present invention.

FIG. 5 is an enlarged schematic view of a joint interface between a yoke part and a cylinder part.

FIG. 6 is an explanatory diagram of a second configuration example of the present invention.

FIG. 7 is an explanatory diagram of a caliper of a third configuration example of the present invention.

FIG. 8 is an explanatory diagram of a caliper of a fourth configuration example of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Bridge part 12 Caliper claw part 14 Yoke part 16 Caliper arm part 18 Cylinder part 20 Yoke part form 22 Cylinder part form 23 Projection 24 Caliper form 25 Depression groove 26 Metal shielding material 30 Reinforcement material 32 Reinforcement material block form 34 Aluminum single part

Claims (3)

[Claims] 1. A brake caliper comprising a yoke part and a cylinder part, wherein the yoke part has ceramic fibers,
Whiskers, foams formed by a ceramic material such as particles and the like in the actual size are inherent, and the cylinder portion is formed of the same metal as the matrix metal impregnated in the yoke portion foam, and the metal base in the yoke portion foam is formed. A brake caliper characterized in that a cylinder portion metal is integrated and fused together through a cylinder. 2. A ceramic foam is formed in accordance with the shape of the required portion of the strength of the brake caliper, and other portions are formed of a high-temperature burnable material such as styrene foam. A method for manufacturing a brake caliper, comprising forming a space cavity in which a part is burned out, impregnating and filling a molten metal into the space cavity, and integrally integrating a metal mass via a metal group in the foam. . 3. A method of manufacturing a brake caliper, comprising:
The caliper yoke is formed from ceramic materials such as ceramic fibers, whiskers, particles, etc. to a substantially actual size, and the cylinder foam is formed from a high-temperature burnt material, and these are joined and integrated to form a caliper foam. The surface is covered with a shielding material, and the aluminum or an alloy thereof serving as a caliper base material is filled in the caliper foam under heating to impregnate the caliper in the cylinder foam and the gap of the yoke ceramic foam. And a method of manufacturing a brake caliper.