JPS626134B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multi-plate disc in which a carrier body that straddles a plurality of wheels and a disc that rotates integrally with the disc and has an operating part equipped with a piston that presses a friction pad on the disc is supported by a bracket. It's about brakes.

This type of disc brake is operated by supplying brake fluid to a hydraulic chamber through a piston installed in the operating part of the caliper body, and the braking action is performed by frictionally engaging the friction pads with a disc that rotates with the wheels. .

However, this frictional braking inevitably generates frictional heat, and this generated frictional heat is transmitted to each member of the brake mechanism and increases its temperature, especially during braking at high speeds, continuous descents on long slopes, etc. During repeated braking for short periods of time, the brake mechanism becomes extremely hot due to the frictional heat generated.
Damage to rubber piston seals, dust boots, etc.
Furthermore, the brake fluid that activates the piston boils and evaporates, creating bubbles, which causes air to enter the hydraulic chamber and prevent the brake from working, a so-called vapor lock phenomenon, which reduces brake efficiency. This was the cause of a significant drop in the performance.

For this reason, asbestos-based friction materials with low thermal conductivity are used for friction pads, but they wear quickly and shorten the life of the friction pads. When used in friction pads, it exhibits high thermal conductivity, which tends to cause the vapor lock phenomenon, and it is necessary to insert a heat insulating material between the back plate of the friction pad and the piston.
In addition, in small disc brakes, the effective thickness of the friction pads cannot be increased, and the friction pads have to be replaced in a short period of time.

The present invention was made against the background of the above circumstances, and the lining of the friction pads arranged between the discs of a multi-disc brake has a thermal conductivity higher than that of the linings of the friction pads on the actuating part side and the reaction part side. The friction material has excellent wear resistance, and the effective thickness of the lining of the friction pad disposed between the disks is smaller than the effective thickness of the lining on the actuating part side and the reaction part side, The purpose is to prevent as much as possible the frictional heat generated in the friction pads due to braking from being transferred to the brake fluid on the braking unit side, thereby effectively preventing the vapor lock phenomenon, suppressing the fade phenomenon, and further improving the lining. To provide a disc brake in which the lining thickness can be selected according to the material, the replacement timing of each pad can be set at the same time, and a caliper body with a narrow disc straddle width can be obtained.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

1 and 2 are disks that rotate together with the wheel; disk 1 is fixed to the axle 5 together with the wheel 4 by a wheel bolt 3; disk 2 is fitted into the serrations 1a of disk 1, and rotates together with the disk 1; It is designed to be able to move in the direction of the axle. 6 is the carrier body, bridge part 7
It straddles the disks 1 and 2 and is integrally formed with an actuating part 8 and a reaction part 9. The caliper body 6 is supported movably in the axle direction by caliper support pins 12, 12 inserted through support arms 11, 11 of a bracket 10 fixed to the vehicle body.

13 is a friction pad placed on the operating part 8 side, 14
15 is a friction pad placed between the disk 1 and the disk 2, and each friction pad 13, 14, 15 is connected to the lining 13a, 14a, 15a and the back plate 13.
b, 14b, and 15b. And the lining 13a of the friction pads 13, 14,
The lining 15a of the friction pad 15 is made of a material with low thermal conductivity, such as an asbestos-based friction material that does not damage the disks 1 and 2 and does not easily generate abnormal noises such as squealing.
The effective thickness of the linings 13a and 14a is made by using a sintered or metallic friction material that has higher thermal conductivity than those of linings 13a and 14a, has a stable coefficient of friction from low to high speeds, and has excellent wear resistance. The thickness is set larger than the effective thickness of the lining 15a.

16 is a cylinder formed in the actuating part 8; 17 is a piston that presses the friction pad 13;
Brake fluid is supplied from a supply port 19 to a hydraulic pressure chamber 18 formed by the outer bottom of the piston 17 and the cylinder 16 . 20 is an annular piston seal provided in cylinder 16, 21 is cylinder 1
This is an annular dust boot provided between the piston 6 and the piston 17.

Next, the operation will be explained. When the brake master cylinder is operated to supply brake fluid to the hydraulic pressure chamber 18, the piston 17 moves forward due to the hydraulic pressure, and presses the lining 13a of the friction pad 13 against the disk 1. Due to the reaction force caused by this pressure contact, the caliper body 6 moves in the opposite direction to the operating direction of the piston 17, the reaction part 9 pushes the friction pad 14, and the disk 2 moves toward the disk 1 side accordingly. As a result, the linings 13a, 14a, 1
5a comes into pressure contact with the disks 1 and 2, respectively, and the disks 1 and 2 stop rotating.

By the way, when such braking is performed repeatedly during high-speed rotation of the discs 1 and 2 or for a long time or a short time, frictional heat is generated due to the sliding contact between the discs 1 and 2 and the linings 13a, 14a, and 15a. Occur.

This frictional heat is blocked by the linings 13a and 14a made of asbestos-based friction material with low thermal conductivity, and the heat conduction from the back plate 13b to the piston 17 and the actuating part 8 is reduced, and the back plate 14b, the reaction part 9,
Heat conduction from the bridge part 7 to the piston 17 and the actuating part 8 is similarly reduced, making it possible to suppress the temperature rise of the brake fluid in the hydraulic pressure chamber 18, causing the brake fluid to boil and evaporate, generating bubbles. The vapor lock phenomenon caused by this is effectively prevented.

Furthermore, by making the lining 15a between the disks 1 and 2 of a sintered or metallic material, the so-called fade phenomenon in which the coefficient of friction of the lining rapidly decreases due to an increase in frictional heat is suppressed.

Since the present invention is configured as described above, the transmission of frictional heat generated during braking to the piston and the operating part is reduced by the lining made of asbestos-based friction material with low thermal conductivity, which increases the temperature of the brake fluid. The vapor lock phenomenon caused by this can be effectively suppressed. Also,
The lining of the friction pads placed between the discs is made of a material with excellent abrasion resistance, so even though the friction pads are located in a position that has poor heat dissipation, the binder of the lining melts due to the increase in frictional heat and the lining It is possible to suppress the so-called fade phenomenon in which the friction coefficient suddenly decreases. The lining made of asbestos-based friction material is less likely to damage the disc, is less likely to generate abnormal noises such as squealing, and wears out faster than the lining made of sintered or metallic friction material placed between the discs. Since the effective thickness of the friction pads has been increased, the friction pads can be replaced at the same time, and the effective thickness of the lining of the friction pads placed between the discs can be reduced. This has advantages such as the ability to reduce the size of the multi-disc brake.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a partially cutaway plan view, and FIG. 2 is a sectional view of FIG. 1. 1 and 2 are disks, 6 is a carrier body, 8 is an operating part, 9 is a reaction part, 13, 14, 15 are friction pads, 13a, 14a, 15a are their linings, 13b, 14b, 15b are their back plates, 16
17 is a cylinder, 17 is a piston, and 18 is a hydraulic chamber.

Claims (1)

[Scope of Claims] 1. A multi-disc brake in which a carrier body is supported by a bracket, and has an operating part that straddles a plurality of discs that rotate together with a wheel and is equipped with a piston that presses a friction pad against the discs, The lining of the friction pad disposed between the disks is made of a friction material having higher thermal conductivity and superior wear resistance than the linings of the friction pads on the operating part side and the reaction part side, and the lining is made of a friction material having higher thermal conductivity and excellent wear resistance. A multi-plate disc brake characterized in that the effective thickness of the lining of the friction pad is smaller than the effective thickness of the linings on the actuating part side and the reaction part side. 2. The lining of the friction pad disposed between the disks is made of a sintered or metallic friction material, and the linings of the actuating part side and the reaction part side are made of an asbestos-based friction material. The multi-disc brake described in item 1.