KR102183119B1 - Brake disc composed of metal and ceramic matrix composite - Google Patents

Abstract

The metal and CMC combination brake disc according to the present invention,
Loads made of metal; And
It characterized in that it comprises a friction unit composed of unit CMC pieces made of a ceramic matrix composite, coupled to the upper and lower surfaces of the load unit.
Using the present invention, it is possible to solve the thermal deformation and deterioration of pads, hat parts, and caliper without making the disk larger than that of the cast iron brake disk while having all the advantages of the CMC brake disk.

Description

Brake disc composed of metal and ceramic matrix composite}

The present invention relates to an automobile brake disk.

Automobile brake disks are divided into drum type brake disks and disk type brake disks.

Disc brakes slow down or stop the rotation of the disk due to friction between the surface of the disk and the pad, thereby slowing down the speed of the vehicle or stopping the vehicle.

In general, disc-type brakes are made of cast iron, but in high-performance and high-spec vehicles, discs are made of ceramic matrix composite (CMC).

The ceramic matrix composite is a material whose matrix is ceramic and reinforced with reinforcing fibers (carbon fiber, silicon carbide fiber, etc.), and is lightweight, has high thermal shock resistance, oxidation resistance, abrasion resistance, high strength, and a high coefficient of friction.

Hereinafter, a disc-type brake disc made of cast iron is referred to as a “cast iron brake disc”, and a disc-type brake disc made of a ceramic matrix composite is referred to as a “CMC brake disc”.

CMC brake discs have higher specific heat than cast iron brake discs but have a smaller density. Therefore, during braking, the temperature of the disk rises more rapidly than the cast iron brake disk due to friction between the surface of the disk and the pad. Because of this, the CMC brake disc itself, which can withstand high temperatures sufficiently, does not have any problem, but heat spreads rapidly to the pads, hat parts, and calipers installed around it, causing thermal deformation and deterioration of the pads, hat parts, and caliper. Let it.

When the pad is thermally deformed and deteriorated, the range of change in the coefficient of friction between the disk and the pad increases, resulting in an inconsistent braking performance.

When the hat part is thermally deformed and deteriorated, there is no balance between the wheel wheel and the hat part, resulting in noise and vibration.

When the caliper is thermally deformed and deteriorated, the caliper cannot properly adhere the pad to the disk, resulting in noise and vibration. In addition, when the caliper is heated, the brake fluid that operates the caliper will boil, and the braking performance will drop sharply.

In order to solve this problem, the CMC brake disk is made larger than the cast iron brake disk (the outer diameter is 1 inch larger), and the volume is increased to prevent the temperature of the brake disk from rising rapidly.

However, in this case, the size of the brake disk is different, and another problem arises that the cast iron brake disk cannot be immediately replaced with the CMC brake disk before the vehicle is remodeled.

Korean registered patents (10-1608904, 10-1610131)

An object of the present invention is to provide a metal and CMC combination brake disk capable of solving the above-described problems.

A metal and CMC combination brake disk for achieving the above object,

Loads made of metal; And

It characterized in that it comprises a friction unit composed of unit CMC pieces made of a ceramic matrix composite, coupled to the upper and lower surfaces of the load unit.

In the present invention, the load part is made of the same cast iron as the general brake disk, and the temperature of the load part is prevented from rapidly increasing during braking. On the other hand, the friction part is made of CMC that is light, has high thermal shock resistance, oxidation resistance, abrasion resistance, high strength, and a high coefficient of friction, and has high wear resistance and high braking performance.

Therefore, by using the present invention, it is possible to solve the thermal deformation and deterioration of the pad, hat part, and caliper without making the disk larger than the cast iron brake disk while having all the advantages of the CMC brake disk.

Also, there is no need to make the brake disc larger than the cast iron brake disc, so the cast iron brake disc can be replaced immediately with the CMC brake disc. Therefore, in order to mount the CMC brake disc, there is no need to modify the vehicle.

In the present invention, the friction portion is composed of unit CMC pieces made of a ceramic matrix composite. Therefore, if a part of the friction part is damaged, quick repair is possible by replacing the unit CMC piece of that part.

1 is a view showing a state in which a hat part is coupled to a metal and CMC combination brake disk according to an embodiment of the present invention.
2 is an enlarged view of portion A shown in FIG.
3 is a view showing the unit CMC piece shown in FIG.
4 is a view showing a unit CMC piece according to the first modification.
5 is a view showing a unit CMC piece according to a second modified example.
6 is a view showing a carbon-carbon fiber.

Hereinafter, a metal and CMC combination brake disk according to an embodiment of the present invention will be described in detail.

As shown in FIG. 1, the metal and CMC combination brake disk 100 is composed of a load unit 110 and a friction unit 120.

The load unit 110 supports the friction unit 120. The load unit 110 absorbs the impact and discharges frictional heat generated during braking to the outside. The thickness of the load part 110 is 25-50mm. The load part 110 is made of a metal such as gray cast iron. The load part 110 is made of metal, thereby increasing the density than the load part made of conventional CMC. For this reason, the temperature of the disk does not rise rapidly during braking.

Cooling channels 111 are provided on the upper and lower surfaces of the load unit 110 in a straight line toward the center of the disk. The cooling channels 111 are arranged at regular intervals in the circumferential direction. The cooling channels 111 are separated by a partition wall 112. Of course, the shape of the cooling channel 111 may be various, such as a curve.

As shown in FIG. 2, the partition wall 112 is composed of a first partition wall 112a and a second partition wall 112b.

Two fastening holes 112aa are provided on the upper surface of the first partition wall 112a, and an end 112ab is formed at the front end of the first partition wall 112a. Of course, the number of fastening holes 112aa may be two or more.

The second partition wall 112b does not have an end and a fastening hole, and is disposed between the first partition wall 112a.

A passage 112ba for communicating the cooling channels 111 disposed on both sides of the second partition 112b is formed on the front side of the second partition 112b. Due to the passage 112ba, air flow in the cooling channel 111 becomes active, and the disk cooling performance of the cooling channel 111 is improved.

The hat part 130 is coupled to the center of the load part 110. The hat part 130 connects the wheel wheel and the disk. The hat part 130 is made of aluminum. In the center of the hat part 130, a shaft hole 131 through which a vehicle wheel shaft passes is provided. Around the shaft hole 131, fastening holes 132 are provided at regular intervals. The bolt passes through the fastening hole 132 to couple the hat part 130 to the wheel wheel.

As shown in Figure 2, at the edge of the hat part 130, a plurality of long holes 133 are drilled at regular intervals. The bush 134 is inserted into the long hole 133. The bush 134 is made of stainless steel. After the bolt 135 passing through the load part 110 passes through the bush 134, when the nut 136 is fastened to the end of the bolt 135, the hat part 130 on the upper surface of the load part 110 Is fixed.

During braking, the friction unit 120 directly frictionally contacts the pad to generate a friction force required for braking.

The friction unit 120 is composed of unit CMC pieces 121 coupled to the upper and lower surfaces of the load unit 110. The thickness of the friction part 120 is 1 to 20 mm.

The unit CMC piece 121 has a size enough to cover the two cooling channels 111. Of course, the size and number of the unit CMC piece 121 may vary.

As shown in Figure 3, the unit CMC piece 121 is provided with two through holes (121a). After the fastening means 122 such as screws or rivets pass through the through hole 121a, it is fastened to the fastening hole 112aa of the first partition wall 112a. Then, the unit CMC piece 121 is fixed to the upper surface of the first partition wall 112a. Of course, the fixing method of the unit CMC piece 121 and the first partition wall 112a may be various.

The unit CMC piece 121 is composed of carbon fiber (Cf), silicon (Si), carbon (C), and silicon carbide (SiC).

Silicon carbide (SiC) constitutes a matrix, and carbon fibers (Cf) are randomly distributed in the matrix. Carbon fiber (Cf) is composed of a bundle of carbon filaments.

In the unit CMC piece 121, the carbon fiber (Cf), silicon (Si), carbon (C), and silicon carbide (SiC) components make the disk light, thermal shock resistance, oxidation resistance, abrasion resistance, high strength, and high Make it have a coefficient of friction.

Modification 1

As shown in Figure 4, the unit CMC piece 121' according to the first modified example is carbon fiber (Cf), silicon (Si), carbon (C), silicon carbide (SiC), copper (Cu), and silicon. -It is composed of copper alloy (SixCuy).

The unit CMC piece 121 ′ according to the first modification further includes copper (Cu) and silicon-copper alloy (SixCuy) components that were not present in the unit CMC piece 121.

As the unit CMC piece 121 ′ further includes copper (Cu) and silicon-copper alloy (SixCuy) components, the density of the unit CMC piece 121 ′ is increased. Accordingly, it is possible to prevent the temperature of the friction unit 120 from rapidly increasing during braking. Of course, even if the temperature of the friction unit 120 rises rapidly, it does not adversely affect the pads, hat parts, and calipers installed around the disk as much as the temperature of the load unit 110 increases rapidly, but the friction unit 120 ), the rapid increase in temperature also does not have a good effect, so the first modification is a modification that has its own meaning.

Silicon carbide (SiC) constitutes a matrix, and carbon fibers (Cf) are randomly distributed in the matrix. Carbon fiber (Cf) is composed of a bundle of carbon filaments.

Carbon fiber (Cf), silicon (Si), carbon (C), and silicon carbide (SiC) components make the disk light, heat shock resistance, oxidation resistance, wear resistance, high strength, and high coefficient of friction.

On the other hand, copper (Cu) and silicon-copper alloy (SixCuy) components increase the density of the disk, prevent the temperature of the disk from rising rapidly during braking, and reduce the variation in the coefficient of friction.

2nd modified example

As shown in Fig. 5, the unit CMC piece 121" according to the second modification is composed of carbon-carbon fibers (C/Cf), silicon (Si), carbon (C), and silicon carbide (SiC). .

In the unit CMC piece 121" according to the second modification, instead of the carbon fiber (Cf) constituting the unit CMC piece 121, a carbon-carbon fiber (C/Cf) is included, and a carbon-carbon fiber (C /Cf) has a higher content of silicon carbide (SiC).

By increasing the content of silicon carbide (SiC) in the unit CMC piece 121", the density of the unit CMC piece 121" increases. Accordingly, it is possible to prevent the temperature of the friction unit 120 from rapidly increasing during braking. Of course, even if the temperature of the friction unit 120 rises rapidly, it does not adversely affect the pads, hat parts, and calipers installed around the disk as much as the temperature of the load unit 110 increases rapidly, but the friction unit 120 ), a rapid increase in temperature also does not have a good effect, so the second variant is a variant that has its own meaning.

Silicon carbide (SiC) constitutes a matrix, and carbon-carbon fibers (C/Cf) are randomly distributed in the matrix.

As shown in Figure 6, carbon-carbon fiber (C / Cf),

It is composed of a carbon layer CL that fills the empty space S between the bundle of carbon filaments FL and the bundle of carbon filaments FL, and surrounds the outer periphery of the bundle of carbon filaments FL. The number of carbon filaments (FL) is thousands to tens of thousands.

The carbon (C) constituting the carbon layer (CL) is impregnated with resin in the bundle of carbon filaments (FL), and the process of carbonizing the bundle of carbon filaments (FL) impregnated with the resin is repeated. Is supplied.

Due to the carbon layer (CL) that fills the empty space (S) between the bundles of carbon filaments (FL) and surrounds the outer periphery of the carbon filaments (FL), the crack generated in the matrix due to the impact generated during braking is carbon It cannot pass through the filament (FL). Even if the carbon layer (CL) surrounding the outer edge of the carbon filament (FL) is pierced, the crack is no longer due to another layer of carbon layer (CL) filling the empty space (S) between the carbon filaments (FL). Can't proceed.

Accordingly, it is possible to sufficiently maintain the strength of the friction portion 120 even with a smaller amount of carbon fiber (Cf), so that the silicon carbide (SiC) content of the friction portion 120 is more than when using carbon fiber (Cf). It can be higher.

The weight ratio of the weight of carbon-carbon fibers (C/Cf) to the weight of silicon carbide (SiC) in the unit CMC piece 121" (carbon-carbon fiber weight/silicon carbide weight) is less than 1 to 0.4 or more. More preferably Is, the weight ratio of carbon-carbon fibers (C/Cf) and silicon carbide (SiC) is 4:6.

In order to increase the amount of silicon carbide (SiC) in this way, silicon carbide powder is directly added in the process of making the unit CMC piece 121". Or, to make the unit CMC piece 121", composed of carbon fiber and carbon In the process of impregnating the carbide with silicon, a catalyst is used to promote the reaction between carbon and silicon to increase the synthesis efficiency of silicon carbide.

100: metal and CMC combination brake disc
110: load portion 120: friction portion
111: cooling channel 112: bulkhead
112a: first partition 112b: second partition
121,121',121": unit CMC piece
SiC: silicon carbide Cf: carbon fiber
C/Cf: carbon-carbon fiber CL: carbon layer

Claims (5)

Loads made of metal;
A friction unit composed of unit CMC pieces made of a ceramic matrix composite material coupled to the upper and lower surfaces of the load unit; And
It includes a hat part made of metal coupled to the central portion of the load,
Each of the unit CMC pieces,
Carbon-carbon fiber (C/Cf), silicon (Si), carbon (C), carbonization consisting of a carbon layer that fills the empty space between the bundle of carbon filaments and the bundle of carbon filaments and surrounds the outer periphery of the bundle of carbon filaments It is composed of silicon (SiC),
The outer circumferential surface of the hat part is coupled to the center of the load unit in contact with the front surface of the CMC pieces,
Partition walls extending in a straight line toward the center of the disk are alternately protruded on each of the upper and lower surfaces of the load part, and the CMC pieces are covered on the partition walls, thereby forming a cooling channel between the partition walls,
The partition walls are composed of a first partition wall and a second partition wall arranged alternately,
A metal and CMC combination brake disk, characterized in that an end is formed at a front end of the first partition wall, and a passage is formed at a front side of the second partition wall. delete delete delete delete

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