JPH0861402A - Brake drum for vehicle - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a brake drum for a vehicle in which abnormal noise is suppressed, a stable braking effect is obtained, and abrasion powder of the lining material does not accumulate in the braking device. [Structure] A disk-shaped bottom wall 31a fixed to a wheel 28
And a peripheral wall 31b extending from the outer peripheral edge of the bottom wall 31a in parallel with the axis α of the wheel 28. In the bottomed cylindrical vehicle brake drum 31, the peripheral wall 31b communicates the inside and outside of the brake drum 31. A plurality of through holes 40 are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle brake drum.

[0002]

2. Description of the Related Art A vehicle is equipped with a brake device for decelerating or stopping the vehicle. The brake device is roughly classified into a disc type and a drum type. Among them, the drum type brake device applies a brake lining to an inner surface of a peripheral wall of a metal brake drum that rotates together with wheels for braking. The structure of the mechanical drum brake device used in a vehicle such as a motorcycle will be described below with reference to FIGS.

As shown in FIG. 5 (a), a drum brake device 1 has a bottomed cylindrical metal brake drum 2 which rotates together with a wheel, and a pair of left and right circular arcs whose one end is supported by an anchor pin 3. Brake shoes 4 and brake cams 5 arranged between the free ends of these brake shoes 4,
A cam lever 6 whose one end is connected to the brake cam 5
And a return spring 7 mounted elastically between the brake shoes 4. A lining material 8 is attached to the outer peripheral surface of each brake shoe 4. As the lining material 8, generally used is a mold lining in which asbestos is molded together with a binder such as a synthetic resin or a rubber material under high temperature and high pressure. Each member other than the brake drum 2 is attached to a brake shoe plate (not shown).

By gripping a brake lever (not shown) or depressing the brake pedal, a force is transmitted to the cam lever 6 through the cable and the rod 9, and the brake cam 5 is rotated as shown in FIG. 5 (b). And
As the brake cam 5 is rotated, the brake shoe 4 is pressed against the inner peripheral surface 2a of the peripheral wall of the brake drum 2 as indicated by the arrow X, and sexual power is generated by the friction between the lining material 8 and the brake drum 2. It has become.
When the brake is released, the brake shoe 4 is returned by the action of the return spring 7 and the braking action is lost.

[0005]

However, due to the friction between the lining material and the brake drum, the surface of the lining material is abraded and abrasion powder is generated, and the abrasion powder adheres to the surface of the lining material and the lining material increases with time. The surface becomes a mirror surface. As a result, when the lining material is pressed against the inner peripheral surface of the peripheral wall of the brake drum, an abnormal noise commonly called "brake squeal" is generated.

Further, since the surface of the lining material is mirror-finished, the coefficient of friction changes, and the braking effectiveness is reduced.

Furthermore, abrasion powder of the lining material accumulates in the braking device and must be regularly removed.

The present invention has been made in consideration of the above-mentioned circumstances, and is for a vehicle in which abnormal noise is suppressed, a stable braking advantage is obtained, and abrasion powder of the lining material is not accumulated in the braking device. The purpose is to provide a brake drum.

[0009]

In order to solve the above-mentioned problems, a vehicle brake drum according to the present invention has a disk-shaped bottom wall fixed to a wheel as described in claim 1. A bottomed cylindrical vehicle brake drum having a peripheral wall extending from the outer peripheral edge of the bottom wall in parallel with the axis of the wheel, wherein the peripheral wall is provided with a plurality of through holes for communicating the inside and outside of the brake drum. Is.

[0010]

In the present invention having the above structure, a bottomed cylindrical shape is fixed to the wheel and has a disk-shaped bottom wall and a peripheral wall extending from the outer peripheral edge of the bottom wall in parallel with the axis of the wheel. Since a plurality of through-holes that communicate the inside and outside of the brake drum are provided on the peripheral wall of the vehicle brake drum, the generation of abnormal noise is suppressed by the abrasion powder of the lining material being discharged from the through-holes, which is stable. A braking advantage is obtained, and abrasion powder of the lining material is not accumulated in the braking device.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a left side view showing an example of a scooter type vehicle as a vehicle to which the present invention is applied. As shown in FIG. 1, the scooter type vehicle 11 has a body frame 12
The body frame 12 has a down tube 14 extending obliquely downward from the head pipe 13 and a monocoque structure formed by pressing a steel plate, for example.
4 and a rear frame 15 whose front portion is fixedly attached. An interior of the rear frame 15 is an article storage chamber 16 capable of storing a helmet or the like, and a driving seat 17 is installed above the article storage chamber 16 so as to be openable and closable.

Reference numeral 18 denotes an engine unit as a power unit, which includes an engine (not shown) and a conductive case 19 extending rearward from one side of the engine, and a rear wheel 20 serving as a drive wheel at a rear end of the conductive case 19. Is held. The engine unit 18 also serves as a swing arm, and the front end of the engine unit 18 is swingably attached to a pivot shaft 22 provided at the rear end of the down tube 14 via a link 21 and the rear end thereof is swingable. Is elastically supported by the rear frame 15 by the rear shock absorber 23.

A front fork 24 is held on the head pipe 13, and a front wheel 25 is held on the lower end thereof.
Reference numeral 26 is a handlebar, and the handlebar 26 steers the front wheel 25 so as to be rotatable left and right.
In addition, front and rear wheels 20,
25 brake levers 27 are provided. A brake device 30 is provided on each of the front wheels 28 of the front wheels 25 and the rear wheels 29 of the rear wheels 20, which are not shown in detail.

FIG. 2 is a left side view of the front wheel 28, and FIG. 3 is a vertical sectional view of the front wheel 28 taken along the line III-III in FIG.

As shown in FIGS. 2 and 3, this vehicle 1
The brake device 30 used in the first embodiment is a general mechanical drum brake device.
Includes a brake drum 31, a pair of left and right arcuate brake shoes 33 supported at one end by an anchor pin 32, a brake cam 34 arranged between the free ends of these brake shoes 33, and a brake cam 34. The cam lever 35 having one end connected, the return spring 36 mounted between the brake shoes 33, and the brake drum 3
1 and a brake shoe plate 37 that closes the opening. A lining material 38 is attached to the outer peripheral surface of each brake shoe 33. The brake drum 3
Each member other than 1 is attached to the brake shoe plate 37 as shown in FIG. One end of a brake cable 39 is connected to the other end of the cam lever 35, and the other end of the brake cable 39 is connected to the brake lever 27.

The brake drum 31 is made of metal and has a bottomed cylindrical shape having a disk-shaped bottom wall 31a and a peripheral wall 31b extending from the outer peripheral edge of the bottom wall 31a in parallel with the axis α of the front wheel 28. It is fixed to the spokes 28a and the hub 28b of the front wheel 28 and rotates together with the front wheel 28. The lining material 38 is formed by molding asbestos, which is generally called molding, under high temperature and high pressure together with a binder such as a synthetic resin or a rubber material.

The peripheral wall 31b of the brake drum 31
Is provided with a plurality of through holes 40 that allow the inside and outside of the brake drum 31 to communicate with each other. As shown in FIG. 4, the through hole 40 is provided over the entire width direction of the peripheral wall 31b so as to cover the entire width direction of the lining material 38.

The structure of the brake device provided on the rear wheel 29 of the rear wheel 20 is the same as that of the front wheel 25.
It is almost the same as 0.

Next, the operation of this embodiment will be described.

By gripping the brake lever 27, a force is transmitted to the cam lever 35 through the brake cable 39, and the brake cam 34 is rotated. When the brake cam 34 is rotated, the brake shoe 33 is pressed against the inner peripheral surface 31c of the peripheral wall 31b of the brake drum 31, and sexual power is generated by the friction between the lining material 38 and the brake drum 31. When the brake lever 27 is loosened, the brake shoe 33 is returned to its original position by the action of the return spring 36, and the braking action is released.

By the way, the surface of the lining material 38 is abraded due to friction between the lining material 38 and the brake drum 31, and abrasion powder is generated.
By providing a plurality of through-holes 40 for communicating the inside and outside of the brake drum 31 in 1b, the abrasion powder is discharged from the through-hole 40 to the outside of the brake drum 31, so that the surface of the lining material 38 is prevented from being mirror-finished and the lining. Material 3
It becomes difficult for abnormal noise (squeaking of the brake) to occur when 8 is pressed against the inner peripheral surface 31c of the peripheral wall 31b of the brake drum 31.

Further, since the abrasion powder is discharged from the through hole 40 to the outside of the brake drum 31, the surface of the lining material 38 is always kept clean, and as a result, the friction coefficient does not change and a stable brake is obtained. You can get a handedness.

Further, since the abrasion powder is discharged from the through hole 40 to the outside of the brake drum 31, the abrasion powder of the lining material 38 does not accumulate in the brake drum 31, and periodical removal of the abrasion powder is unnecessary. .

Furthermore, the through hole 40 also enhances the effect of radiating the heat generated by the friction between the lining material 38 and the brake drum 31, and is excellent in fade resistance.

[0026]

As described above, according to the vehicle brake drum of the present invention, the disc-shaped bottom wall is fixed to the wheel and the outer peripheral edge of the bottom wall is parallel to the axis of the wheel. In a bottomed cylindrical vehicle brake drum having an extending peripheral wall, since a plurality of through-holes communicating the inside and outside of the brake drum are provided in the peripheral wall, abrasion powder of the lining material is discharged from the through-hole. As a result, generation of abnormal noise is suppressed, a stable braking effect is obtained, and abrasion powder of the lining material does not accumulate in the braking device.

[Brief description of drawings]

FIG. 1 is a left side view of a scooter type vehicle as a vehicle showing an embodiment of a vehicle brake drum according to the present invention.

FIG. 2 is a left side view of a front wheel.

3 is a vertical cross-sectional view of the front wheel taken along the line III-III in FIG.

FIG. 4 is a schematic perspective view of a brake drum.

5A and 5B are structural views of a conventional mechanical drum brake device used in a vehicle.

[Explanation of symbols]

 11 Scooter type vehicle 24 Front fork 25 Front wheel 26 Handlebar 27 Brake lever 28 Front wheel 30 Brake device 31 Brake drum 31a Brake drum bottom wall 31b Brake drum peripheral wall 31c Circumferential wall inner surface 33 Brake shoe 34 Brake cam 35 Cam lever 38 Lining material 39 Brake cable 40 Through hole α Front wheel axis

Claims (1)

[Claims] 1. A disc-shaped bottom wall fixed to a wheel,
In a bottomed cylindrical vehicle brake drum having a peripheral wall extending from the outer peripheral edge of the bottom wall in parallel with the axis of the wheel, the peripheral wall is provided with a plurality of through holes for communicating the inside and outside of the brake drum. A brake drum for a vehicle, which is characterized in that