KR20050069669A - Brake disc structure for vehicle - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake disc structure for a vehicle, wherein the outer surface of the disc plate constituting the brake disc, which is manufactured from a ceramic matrix composite material, is radially from the center of the disc when viewed from a cross section rather than a flat surface as in the prior art. By changing the disk shape of the curved curve as it goes, the contact area between the disk and the pad at the same disk radius is increased, thereby improving the brake disk structure for a vehicle for improved braking performance.

Description

Brake disc structure for vehicle

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake disc structure for a vehicle, wherein the outer surface of the disc plate constituting the brake disc, which is manufactured from a ceramic matrix composite material, is radially from the center of the disc when viewed from a cross section rather than a flat surface as in the prior art. By changing the disk shape of the curved curve as it goes, the contact area between the disk and the pad at the same disk radius is increased, thereby improving the brake disk structure for a vehicle for improved braking performance.

In general, a brake device is a device for continuously decelerating or stopping a vehicle while driving and maintaining the stopped vehicle in a stationary state, and using the friction force generated by the driver's operation force or auxiliary power to convert the kinetic energy of the vehicle into thermal energy. To switch to braking.

Such a brake device includes a braking force generator that generates the force necessary for braking, a braking device that actually decelerates or stops the vehicle by using the force generated by the braking force generator, pipes and pistons that transmit the force of the braking force generator to the braking device. It consists of an auxiliary device for obtaining valves and auxiliary power.

Among these, the brake system is structurally divided into a drum brake and a disk brake.

First, the drum brake has an internally expandable structure consisting of a wheel cylinder, a brake shoe, a back plate, a brake drum, and the like.

In other words, when the brake pedal is pressed, the piston in the master cylinder raises the brake hydraulic pressure, and this pressure is transmitted to the wheel cylinder through the brake pipe, and the wheel cylinder pushes the piston by hydraulic pressure and the brake shoe It is compressed and brakes.

In such a drum type brake, since the lining rubs against the closed drum inner circumferential wall, continuous use reduces the braking effect due to the widening of the gap between the lining and the drum wall due to thermal expansion.

In addition, a fade phenomenon in which the frictional force decreases due to heat at the surface of the lining occurs, and when the drum gets wet with water, such as passing through a water hole, the braking force drops, as well as taking time to dry the drum.

A disc brake is provided to compensate for this drawback, and braking is performed by pads provided on both sides of the brake disc.

That is, in the disc brake, a pair of brake pads is provided to fix the brake disc in parallel to the wheels and to be compressed or spaced on the left and right surfaces of the brake disc.

The hydraulic mechanism and oil pipe (hose) for operating the pads in the disc brake are the same as the drum brake. When the brake pedal is pressed, the oil presses the piston to compress the pad onto the disc. When pressed on both surfaces, frictional force is applied by the pressing force to obtain braking force.

In addition, when the foot is released from the brake pedal, the pad is separated from the disk by the force of the spring, and the frictional heat generated in the disk is cooled by the rotation of the disk.

In the disc brake, the pad portion is also not sealed, and thus heat is not accumulated. Accordingly, even if it is used continuously, the pad does not cause a fade phenomenon and expands in the circumferential direction even after thermal expansion. There is no

In addition, the cooling of the disk prevents chattering.

Since the disc brake stops the rotational movement of the disc or slows down the rotational speed by the frictional force generated by the contact between the brake pad and the disc, the brake disc generally becomes hot due to frictional heat during braking and deteriorates or brakes. In order to prevent this from falling, a vent hole is formed inside the disc to induce the flow of air, thereby allowing a cooling action to occur.

The conventional brake disc structure will be described in more detail as follows.

1 is a perspective view showing a conventional brake disc cutaway, Figure 2a is a cross-sectional view taken along the line 'A-A' of Figure 1, Figure 2b is a cross-sectional view in the direction of the arrow 'B' of Figure 1 .

1, 2A and 2B, reference numeral 12 denotes a disk hub having a plurality of fastening holes 13, reference numerals 14a and 14b denote disk disks, and reference numerals 16 and 18 denote two disk plates 14a and 14b, respectively. Indicate rib and vent hole between.

As shown, the brake disc 10 is formed by integrally casting a central disk hub 12 and two disk-shaped disk plates 14a and 14b arranged in parallel at regular intervals.

A plurality of radially arranged ribs 16 are formed radially long between the two disk plates 14a and 14b, and the ribs 16 connect between the two disk plates 14a and 14b. It is a structure.

In addition, a straight space between two ribs adjacent to each other between the two disk plates 14a and 14b is a vent hole 18, and since the plurality of ribs 16 are radially arranged, a straight vent hole 18 is formed. ) It also has a structure in which a plurality of radially arranged.

That is, the brake disc 10 has a structure in which a plurality of vent holes 18 partitioned by the ribs 16 between two disc-shaped disc plates 14a and 14b are formed to penetrate radially from the center of the disc. .

The vent hole 18 prevents the disk from becoming a high temperature state by repetitive friction by accelerating the rate of divergence of frictional heat caused by the brake pads through a ventilation action while driving.

However, the above disc type brakes have the following problems.

The kinetic energy generated when the car moves is transmitted to the disk of the brake in the form of frictional heat, and as a result, the temperature between the disk and the contact surface of the pad is rapidly increased.

Such friction between the disk and the pad causes thermal problems such as abrasion at the brake friction surface, thermal cracking and thermal deformation, and also unevenly changes the braking force of the brake.

This causes a slight vibration in the disk, and shortens the life of the brake device or causes a failure.

Therefore, by increasing the strength of the disk itself, using a material having a relatively low thermal window coefficient during manufacturing, by cooling the cooling is achieved by the rotation of the disk, to overcome the noise and vibration problems.

However, it was not possible to overcome the limitations of the manufacturing and the properties of the single material, and because of the limitation of casting, the disk had to be made into a flat disc shape, so the expansion of the disk caused by the coefficient of thermal expansion and thermal conductivity was frequently used. Has led to heat island concentration and has shown limitations in reducing the incidence of chattering.

In addition, even if the gap between the disk and the pad is designed so as not to widen, the wear of each other due to friction could not be prevented.

At present, the problems of shortening the lifespan and deterioration of the braking property by the friction in the brake device, where stability is the most important, and the problems of noise and vibration that give the driver psychological anxiety and discomfort are pointed out as important challenges.

Therefore, there is an urgent need for a method for overcoming various problems caused by frictional heat, that is, thermal deformation and heat island phenomena, and noise and vibration caused by them.

Therefore, the present invention was invented to solve the above problems, by changing the shape of the ceramic matrix composite material to the optimum shape that can suppress the heat deformation and heat island phenomenon, the existing noise and vibration The problem can be solved, and at the same time, the shortening of the life of the brake itself can be prevented, and an object thereof is to provide a brake disc structure for a vehicle that can further improve the braking performance.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The present invention relates to a brake disc for a vehicle in which a plurality of vent holes partitioned by ribs are formed to penetrate radially from a center of a disc between two disc-shaped disc plates, the pad being in contact with a ceramic matrix composite material. It characterized in that the outer surface of the disk plate is formed in a gentle curved shape while going radially from the center of the disk.

As a preferred embodiment, the outer surfaces of the two disk plates are both smoothly curved in a radial direction from the center of the disk, but the outer surfaces of the two disk plates gradually expand from each other in a radial direction when viewed in cross section. Characterized in that the shape of the trumpet cross-section structure.

In a preferred embodiment, the outer surface of one of the two disk plates of the two disk plates is in the form of a gentle curved radially from the center of the disk, the other disk plate is the outer surface of the planar shape, When viewed from the cross-section is characterized in that the outer surface of the one side disk plate in the radial direction, the semi-trumpet-shaped cross-sectional structure of the curved surface gradually widening with the outer surface of the other disk plate.

In a preferred embodiment, the outer surfaces of the two disk plates are both smoothly curved in a radial direction from the center of the disk, but the outer surfaces of the two disk plates are gradually gathered with each other in a radial direction when viewed in cross section. It is characterized by a concave cross-sectional structure of a curved shape.

On the other hand, each of the radial vent hole is characterized in that it is formed in a reduced tube shape of reducing the overall cross-sectional area while going radially from the center of the disk.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake disc structure for a vehicle, and by changing the shape of the ceramic matrix composite material into an optimal shape capable of suppressing heat deformation and heat island phenomena, problems such as noise and vibration can be solved. And a brake disc structure for a vehicle which can be prevented from shortening the life of the brake itself at the same time and can further improve braking performance.

First, the brake disc of the present invention is manufactured using a ceramic matrix composite material (CMC) capable of mass-producing various shapes of products instead of conventional cast iron.

The ceramic matrix composite material can obtain strength equivalent or higher at a density about 10 times lower than cast iron, and can produce a brake disk having a coefficient of thermal expansion close to zero and high thermal conductivity.

In addition, the brake disc of the present invention has a disc shape in which the outer surfaces of the two disc plates arranged in parallel are not curved, but curved in a radial direction from the center of the disk when viewed in cross section. By changing, the contact area between the disk and the pad is increased at the same disk radius, and thus the braking property can be improved.

Hereinafter, the brake disc structure of the present invention will be described in more detail.

3 and 4 are cross-sectional perspective views showing a first embodiment and a second embodiment according to the present invention, respectively, and FIG. 5 is a cross-sectional perspective view showing a third embodiment according to the present invention.

Reference numeral 12 denotes a disc hub, and 13 denotes a fastening hole.

As shown in the drawing, the brake disc according to the present invention has a structure in which the outer surface of the disc plate to which the pad is in contact is curved to increase the contact area compared to the brake disc made of the conventional flat disc plate. have.

First, as the first embodiment of the present invention, as shown in Figure 3, the outer surface of both the two disk plate (14a, 14b) is a curved surface inclined gently in the radial direction from the disk center In particular, the outer surfaces of the two disk plates 14a, 14b are inclined outwardly radially from the disk center when viewed from the cross section, that is, have a trumpet-shaped cross-sectional structure in the form of curved surfaces where the two surfaces gradually open to each other.

In the first embodiment of the present invention having such an outer shape, each radial vent hole 18 partitioned by the ribs 16 between the two disk plates 14a and 14b and formed to be long in the radial direction is formed from the disk center. It is provided to form a reduced tube shape in which the cross-sectional area is reduced as a whole going in the radial direction.

On the other hand, as a second embodiment of the present invention, as shown in Figure 4, the outer surface of one of the two disk plate (14a, 14b) of one side disk plate 14a is inclined gently while moving radially from the center of the disk It is in the shape of a curved surface, and the outer side of the disk plate 14b on the other side is planar, but the outer surface of the one side disk plate 14a is radially away from the center of the disk when viewed in cross section. It has a half-trumped cross-sectional structure that is inclined toward one side, i.e., a curved surface that gradually expands from the outer surface of one side.

In the second embodiment of the present invention having such an outer shape, each of the radial vent holes 18 partitioned by the ribs 16 between the two disk plates 14a and 14b and formed to be elongated in the radial direction is the first embodiment. Similarly to the example, it is provided in the shape of a reduction tube in which the cross-sectional area is reduced as a whole from the disk center in the radial direction.

On the other hand, as a third embodiment of the present invention, as shown in Fig. 5, both outer surfaces of the two disk plate (14a, 14b) is a curved surface inclined gently in the radial direction from the center of the disk In particular, the outer surface of the two disk plates 14a, 14b has a concave cross-sectional structure in the form of a curved surface which is collected radially from the center of the disk when viewed in cross section.

In the third embodiment of the present invention having such an outer shape, each of the radial vent holes 18 partitioned by the ribs 16 between the two disk plates 14a and 14b and formed to be elongated in the radial direction is formed of the first and Similarly to the second embodiment, it is provided in the shape of a reduction tube whose cross-sectional area is reduced as a whole from the center of the disk in the radial direction.

In order to apply the disk 10 of each embodiment according to the present invention to the actual brake device, it is a matter of course that the shape of the pressing surface of the pad must be configured in a shape corresponding to the curved shape of each disk.

In this way, when the embodiments of the present invention described above are applied to the brake device, since the contact surface (outer surface) on which the pad is pressed is curved, the contact area between the pad and the disk is increased at the same disk radius. As a result, braking performance can be improved.

In addition, since the ceramic matrix composite material (CMC) has a coefficient of thermal expansion close to zero, when the ceramic matrix composite material is used as a material for a brake disc, noise and vibration due to thermal expansion, etc., are higher than that of a brake disc of a cast iron. Many problems can be solved.

As described above, according to the brake disc structure for a vehicle according to the present invention, a ceramic matrix composite material may be used to suppress thermal deformation and heat island phenomenon, and problems such as noise and vibration may be solved. At the same time, the shortening of the life of the brake itself can be prevented.

In addition, by forming the outer surface of the disk plate that the pad is in contact with the curved surface shape to increase the contact area with the pad more than the conventional brake disk compared to the same disk radius, and finally to obtain an improved braking performance Will be.

1 is a cross-sectional perspective view showing a conventional brake disc cutaway,

2A is a cross-sectional view taken along the line 'A-A' of FIG. 1,

FIG. 2B is a cross-sectional view in the direction of arrow 'B' of FIG. 1,

3 is a cross-sectional perspective view showing a first embodiment according to the present invention;

4 is a cross-sectional perspective view showing a second embodiment according to the present invention;

Figure 5 is a cross-sectional perspective view showing a third embodiment according to the present invention.

<Explanation of symbols for the main parts of the drawings>

10 brake disc 12 disc hub

14a, 14b: disc plate 16: rib

18: vent hole

Claims (5)

In a brake disc for a vehicle in which a plurality of vent holes partitioned by ribs are formed to penetrate radially from a disk center between two disk plates. Brake disk structure for a vehicle, characterized in that the outer surface of the disk plate which the pad is in contact with the ceramic matrix composite material is formed in a gentle curved shape radially from the center of the disk. The method according to claim 1, The outer surfaces of the two disk plates are both smoothly curved in the radial direction from the center of the disk, but in the cross section, the outer surfaces of the two disk plates are curved in the form of curved tally which gradually expand from each other in the radial direction. Brake disk structure for a vehicle, characterized in that the cross-sectional structure. The method according to claim 1, The outer surface of one of the two disk plates on both sides of the disk plate in the radial direction from the center of the disk is in the form of a gentle curved surface, the other disk plate of the outer surface is in a planar shape, when viewed from the cross section Brake disk structure for a vehicle, characterized in that the outer surface of one side of the disk plate in the radial direction and has a semi-trumpet cross-sectional structure of gradually curved with the outer surface of the other disk plate. The method according to claim 1, The outer surfaces of the two disk plates are both smoothly curved in a radial direction from the center of the disk, but in the cross section, the outer surfaces of the two disk plates are curved in a radially converging manner. Brake disk structure for a vehicle, characterized in that the cross-sectional structure. The method according to any one of claims 1 to 4, Each of the radial vent holes is formed in a reduction tube shape in which the overall cross-sectional area is reduced in a radial direction from the center of the disk, characterized in that the vehicle brake disk structure.