JPH0424578B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a multi-disc brake for a vehicle.

[Prior art]

A fixed disk fixed to a disk tightening bolt screwed onto a hub that rotates integrally with the wheel, and a slide disk fitted to the disk tightening bolt through a sleeve so as to be movable in the axle direction. Multi-disc brakes for vehicles use opposing pistons built into the actuating part of the caliper, which is placed across the caliper, to press friction pads against the disc for braking. Efforts have been made to downsize the brake device by increasing the braking area and reducing the diameter of the disc rotor, but this sometimes causes the friction pads to drag.

As a result of various studies, we found that the cause of this problem is that the disc and friction pad require shoe clearance, so the amount of movement of the piston on the sliding disk side during braking is larger than the amount of movement of the piston on the fixed disk side. Therefore, when the brake was released, the amount of piston return on the sliding disk side was smaller than that on the fixed disk side, and the amount of return of the friction pad was smaller, clearly causing dragging.

[Purpose of the invention]

Therefore, the present invention was made based on the above knowledge, and when the brake is released, the return amount of the friction pad is set appropriately to ensure a predetermined clearance between the disc and the friction pad, thereby preventing the friction pad from dragging. To provide multi-disc brakes for vehicles.

[Structure of the invention]

In order to achieve the above object, the present invention straddles a multi-plate disk consisting of a single fixed disk and a sliding disk movable in the disk axial direction, and is built in the actuating part of the caliper disposed on both sides of the multi-plate disk. This multi-disc brake for a vehicle is characterized in that the amount of return of the piston on the sliding disk side is greater than the amount of return of the piston on the fixed disk side.

〔Example〕

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

The multi-plate disk 1 is fixed so as not to move in the axle direction by being held between the hub 3 and the end of a sleeve 5 inserted through a disk tightening bolt 4 screwed onto a hub 3 that rotates together with the axle 2. Fixed disk 6 and disk tightening bolt 4 via sleeve 5
and a slide disk 7 provided movably in the axle direction.

The caliper 8, which is fixed to the vehicle body via a bracket (not shown), straddles the multi-plate disc 1 and has actuating parts 8a and 8b disposed on both sides thereof.
A cylinder 9a is formed in the actuating part 8a disposed on the fixed disk 6 side, and a cylinder 9b is formed in the actuating part 8b disposed on the slide disk 7 side.
Pistons 10a, 10 are provided in the cylinders 9a, 9b.
b is built-in. Friction pads 11 are provided on each surface of the fixed disk 6 and the slide disk rotor 7.
a, 11b, 11c, and 11d are arranged facing each other, and the back plate 12a of the pad 11a and the seat pad 1
1b, 11c common back plate 12b and friction pad 1
A back plate 12c of 1d is inserted through a hanger pin 13 and is suspended by a caliper 8 so as to be slidable in the disk axial direction, and a piston 10a moves forward with pressure fluid supplied into cylinders 9a and 9b by brake operation. , 10b, each friction pad 11
a, 11b, 11c, 11d to each disk 6, 7
The square seals 16, which are fitted in the annular grooves 14 and 15 formed in the respective cylinders 9a and 9b, are pressed against the braking surfaces of the cylinders 9a and 9b to perform braking.
It recovers with the resilience of 17.

By the way, during this brake operation, the piston 10a on the fixed disk 6 side is pressed against one friction pad 1.
1a is pushed and brought into pressure contact with the fixed disk 6,
The piston 10b on the slide disk 7 side pushes the three friction pads 11b, 11c, and 11d to press them against the slide disk 7, so the piston 10a moves by the shoe clearance between the fixed disk 6 and the friction pad 11a. , piston 10b
Since it is necessary to move the fixed disk 6 and the friction pad 11b and the slide disk 7 and the friction pads 11c and 11d by the amount of shoe clearance, the stroke of the piston 10b is longer than that of the piston 10a, and the return amount must also be increased. That is, when assembling the caliper, if the initial shoe clearances between the discs 6, 7 and each friction pad 11a, 11b, 11c, 11d are the same, and each shoe clearance is worn by the same amount, the piston 10a
If the return amount of the piston 10b is A, the return amount of the piston 10b is B, and the number of disks is D, then the relationship is B=(D×2-1)A. For example, if there are two disks,
If there are three disks, then B=3A, and if there are three disks, then B=5A.

Therefore, the return amount of the piston 10b is
The piston 10 is moved so that the return amount is greater than the return amount of 0a.
b needs to be assembled into the cylinder 9b. Therefore,
Specific means for increasing this return amount will be explained below.

Generally, the return of the piston is achieved by the restoring force, or rollback, of the corner seal that deforms as the piston moves forward during braking. A chamfered portion is provided to smoothly perform elastic deformation to ensure a specified amount of rollback and to allow deformation. Therefore, as shown in FIG. 2, the length l of the side in the cylinder axis direction of the chamfered portion 15a of the annular groove 15 of the corner seal 17 formed on the cylinder 9b is equal to that of the annular groove 14 on the fixed disk 6 side. Form the chamfer so that it is larger than the corner seal 1.
A rollback amount of 7 is secured.

Further, as other means, for example, the corner seal 16 of the fixed disk 6 side operating part 8a or the piston 10
Compared to a, the hardness of the corner seal 17 and the piston 10b
The surface roughness may be increased, or the interference between the corner seal 17 and the piston 10b may be increased. Further, a piston forced return mechanism may be provided to adjust the return amount.

〔Effect of the invention〕

As explained above, in a multi-disc brake that brakes multi-disc discs with opposing pistons, the amount of piston return on the sliding disk side is set to be larger than the amount of return of the piston on the fixed disk side. Since the corresponding return amount is obtained, it is possible to prevent the friction pad from dragging between the disk and the disk, and it is possible to eliminate uneven wear of the friction pad and abnormal sliding noise.

[Brief explanation of drawings]

The drawings show an embodiment of the multi-disc brake for a vehicle according to the present invention, and FIG. 1 is a sectional front view, and FIG. 2 is a sectional view of the main part of FIG. 1. 1 is a multi-plate disk, 6 is a fixed disk, 7 is a slide disk, 8 is a caliper, 8a, 8b are operating parts, 9a, 9b are cylinders, 10a, 10b are pistons, 11a, 11b, 11c, 11d are friction pads, 14 and 15 are annular grooves, 15a is a chamfered portion, and 16 and 17 are corner seals.

Claims (1)

[Claims] 1 The friction pad is pressed against the disk by opposing pistons built into the actuating part of the caliper installed on both sides of the multi-plate disk, which is made up of a single fixed disk and a sliding disk that can be moved in the axial direction of the disk. A multi-disc brake for a vehicle, characterized in that the amount of return of the piston on the sliding disk side is greater than the amount of return of the piston on the fixed disk side.