KR20020010984A - Brake drum of drum type brake for vehicle - Google Patents

Abstract

PURPOSE: A brake drum of a drum brake in a vehicle is provided to prevent temperature of the brake drum from increasing by refrigerant in operating a brake and to improve brake performance by reducing wear of the brake lining. CONSTITUTION: A brake drum for a drum brake in a vehicle comprises a brake drum(11) rotating with a wheel by being mounted on a wheel hub through a bolt; a back plate(12) fixed on an axis; a brake shoe(13) mounted on the back plate by being composed of steel; a lining(14) changing movement energy into heat energy by stopping rotation of the brake drum through contacting the brake drum; a refrigerating passage(11a) connected to the brake drum by having a wave shape; a master cylinder generating hydraulic pressure; and a wheel cylinder(15) pressurizing the brake shoe into the brake drum through the hydraulic pressure generated in a master cylinder. The lining is a frictional member by being mounted on an outer surface of the brake shoe. Refrigerant is inserted to the refrigerating passage to prevent temperature of the brake drum from increasing.

Description

BRAKE DRUM OF DRUM TYPE BRAKE FOR VEHICLE}

The present invention relates to a brake drum of an automobile drum brake, and more particularly, to a brake drum of an automobile drum brake in which the cooling performance is improved to reduce the amount of wear of the brake lining and the braking performance is improved.

In general, a brake system is classified into a main brake mainly used for driving and a parking brake used for parking a car, and the main brake is configured to brake the hydraulic pressure generated by the operation of the brake pedal. Hydraulic brakes, hydraulic brakes intended to be used when a large braking force is required, such as a large vehicle, and air brakes that generate braking force by using compressed air pressure. There is a drum type brake to generate a braking force by squeezing a brake shoe with a lining to a rotating brake drum from the inside.

Here, the general configuration of the drum brake 10 is, as shown in Figure 1, the brake drum 11 is installed on the wheel hub via the bolt to rotate with the wheel, and the back plate fixed to the axle ( 12), a brake shoe 13 made of cast iron material provided on the back plate 12, and attached to an outer surface of the brake shoe 13 to be in direct contact with the brake drum 11, Lining 14, which is a friction material to stop the rotation and convert the kinetic energy into thermal energy, and the wheel cylinder 15 for pressing the brake shoe 13 to the brake drum 11 through the hydraulic pressure generated in the master cylinder. Consists of

Therefore, when the brake pedal is pressed while driving, the hydraulic pressure generated in the master cylinder is transmitted to the wheel cylinder 15, and the brake shoe 13 is rotated together with the wheels by the piston movement of the wheel cylinder 15. 11), the brake lining 14 attached to the outer surface of the brake shoe 13 is compressed to the brake drum 11 to stop the rotation of the brake drum 11 by using a friction force. You can brake.

Here, the lining 14 is directly compressed to the brake drum 11 that is rotated during the operation of the brake to generate a strong friction force, the temperature of the brake drum 11 is raised to about 200 ~ 300 ℃ .

However, the conventional drum brake 10 as described above is not provided with a separate device for cooling the brake drum 11 that rises to a high temperature during the operation of the brake, the amount of wear of the brake lining 14 brake There is a problem in that the wear of the drum 11 is increased in proportion to the rising temperature, and as a result, the braking performance deteriorates.

In addition, when the temperature of the brake drum 11 is excessively increased, the friction temperature generated during braking causes damage to the tire, thereby reducing driving stability.

Accordingly, the present invention has been made to solve all the problems described above, by forming a cooling passage in the brake drum while enclosing a coolant in the cooling passage, the temperature of the brake drum is excessively increased by the coolant during brake operation. It is an object of the present invention to provide a brake drum for an automobile drum brake, which is prevented, of course, thereby reducing the amount of wear of the brake lining and improving braking performance.

In the brake drum of the present invention for achieving the above object, a cooling passage having a diameter of a predetermined size is included in the thickness and is connected to the circumferential direction, characterized in that the cooling passage is sealed in the cooling passage.

1 is an exploded perspective view for explaining a drum brake generally used;

2 is a perspective view of a brake drum having a cooling passage according to the present invention;

3 is a partial cross-sectional view taken along line II of FIG. 2.

<Description of Symbols for Main Parts of Drawings>

11-Brake Drum 11a-Cooling Path

14-Brake Lining 20-Coolant

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

Figure 2 is a perspective view of a brake drum provided with a cooling passage according to the present invention, will be described with the same reference numerals to the same parts as the conventional structure.

Drum brake 10 of the present invention, as described above with reference to Figure 1, the brake drum 11 is installed on the wheel hub via the bolt to rotate with the wheel, and the back plate 12 is fixed to the axle ), The brake shoe 13 made of cast iron material provided on the back plate 12, and attached to the outer surface of the brake shoe 13 to be in direct contact with the brake drum 11 to rotate the brake drum 1. Lining 14, which is a friction material to convert the kinetic energy into thermal energy, and the wheel shoe 15 to compress the brake shoe 13 to the brake drum 11 through the hydraulic pressure generated from the master cylinder. consist of.

2 and 3, the cooling passage 11a having a diameter of a predetermined size is connected to the brake drum 11 in a circumferential direction so as to be included on the thickness of the brake drum 11. It is provided.

In addition, the cooling passage 11a is formed in a wave shape so that the brake lining 14 can sequentially pass through a portion contacting the brake drum 11 and a non-contact portion.

On the other hand, when the brake drum 11 is not overheated when the brake is inoperative, the cooling passage 11a maintains a solid state, and when the brake is operated to raise the temperature of the brake drum 11 to a liquid state. As the phase changes, the coolant 20 circulated along the cooling passage 11a is sealed.

That is, the coolant 20 is a metal having a low melting point (for example, sodium having a melting point of 95 ° C.). When the brake is not operated, the coolant 20 maintains a solid state because the brake drum 11 is not overheated. If the brake lining 14 is in contact with the brake drum 11 while the brake is operated and the temperature of the brake drum 11 rises rapidly by about 200 to 300 ° C. due to frictional heat, the cooling passage 11a phase-changes to a liquid state. It is designed to circulate along.

In addition, the coolant 20 is sealed in only about 60% to about 70% of the total area of the cooling passage 11a so that the coolant 20 can be circulated smoothly when it is circulated into a liquid state when the brake is operated. The remaining portion of about 30% to 40% of the total area of the cooling passage 11a is to maintain the vacuum state.

Therefore, when the brake pedal is pressed while driving, the hydraulic pressure generated in the master cylinder is transmitted to the wheel cylinder 15, and the brake shoe 13 is rotated together with the wheels by the piston movement of the wheel cylinder 15. 11) is momentarily moved, the brake lining 14 attached to the outer surface of the brake shoe 13 is pressed on the inner peripheral surface of the brake drum 11 to generate a braking force while generating a strong friction force.

At this time, when the brake lining 14 is pressed against the inner circumferential surface of the brake drum 11 to generate a strong friction force, the temperature of the brake drum 11 is raised to about 200 ~ 300 ℃, the brake drum 11 Coolant 20 encapsulated in the cooling passage (11a) by the high temperature of the melt is circulated along the cooling passage (11a) by the rotation of the brake drum 11, thereby cooling the brake drum (11).

Accordingly, since the amount of wear of the brake lining 14 is proportional to the rising temperature of the brake drum 11, the overall amount of wear is reduced as compared to the conventional drum brake 10 described above with reference to FIG. 1. Since the brake lining 14 can be prevented from being rapidly worn, the braking performance is improved and the driving stability is also improved.

As described above, according to the present invention, a cooling passage in which a coolant is enclosed is provided in the brake drum, and the brake lining is circulated along the cooling passage while the coolant is melted in a liquid state by heat generated by friction of the brake lining with the brake drum during operation of the brake. Therefore, the wear amount of the brake lining is reduced to improve economic efficiency, as well as the phenomenon in which the brake lining is rapidly worn is prevented, thereby improving the braking performance and driving stability.

Claims (4)

The brake drum of the automobile drum brake, characterized in that the cooling passage having a diameter of a predetermined size is included in the thickness and provided to be connected in the circumferential direction. The brake drum of claim 1, wherein the cooling passage is formed in a wave shape so as to sequentially pass through a portion where the brake lining contacts and a non-contact portion. The drum brake of claim 1, wherein the coolant is circulated along the cooling passage while the solid state is maintained when the brake is inactive and the brake is operated to raise the temperature to a liquid state. Break drum. According to claim 1 or 2, wherein the cooling passage, the coolant is encapsulated in about 60% to 70% of the total area so that the coolant can be circulated smoothly when the phase changes into the liquid state and circulated, the remaining portion is vacuum The brake drum of the automobile drum brake, characterized in that to maintain the state.