JP2022187734A - brake pad - Google Patents

Abstract

To provide a brake pad for meeting a technical requirement for efficiently discharging abrasion powder.SOLUTION: The brake pad includes a friction material opposed to the friction surface of a disc rotor, the friction material having a first side face located on the inner periphery side in the radial direction of the disc rotor, a second side face located on the outer periphery side in the radial direction of the disc rotor, and a slit formed in the face opposed to the friction surface of the disc rotor while extending between the first side face and the second side face. The width of the slit measured along the peripheral direction of the disc rotor increases from the inner periphery side in the radial direction of the disc rotor to the outer periphery side.SELECTED DRAWING: Figure 2

Description

The technology disclosed in this specification relates to a brake pad used in a disc brake device.

Patent Literature 1 discloses an example of a brake pad used in a disc brake device.

Japanese Patent Application Laid-Open No. 2003-202040

A disc brake device generates a braking force by pressing a friction material of a brake pad against a rotating brake rotor. Therefore, abrasion powder is generated from the friction material due to friction between the brake rotor and the friction material. If such wear powder remains between the brake rotor and the friction material, it may cause deterioration of friction characteristics and uneven wear. Therefore, such a brake pad requires a technique for efficiently discharging abrasion powder.

The brake pads disclosed herein may comprise a friction material facing the friction surface of the disc rotor. The friction material faces a first side surface located on the radially inner peripheral side of the disk rotor, a second side surface located on the radially outer peripheral side of the disk rotor, and the friction surface of the disk rotor. and a slit extending between the first side and the second side in the face. The width of the slit measured along the circumferential direction of the disk rotor may increase from the radially inner side to the outer side of the disk rotor.

If the friction material is provided with the slit, abrasion powder is efficiently discharged through the slit. In particular, the slit is configured such that the width measured along the circumferential direction of the disk rotor increases from the radially inner side to the outer side of the disk rotor. Therefore, the abrasion powder entering the slit is efficiently discharged from the slit by the centrifugal force generated by the rotation of the disk rotor.

1 is a cross-sectional view schematically showing the configuration of a disc brake device; FIG. It is a figure which shows the perspective view of a brake pad typically. FIG. 4 is a diagram showing the essential parts of the disk rotor viewed from a direction perpendicular to the friction surface, and showing the positional relationship between the disk rotor and the friction material. It is a figure which shows typically the perspective view of the brake pad of a modification.

One embodiment of the brake pad disclosed herein may include a friction material facing the friction surface of the disc rotor. The friction material faces a first side surface located on the radially inner peripheral side of the disk rotor, a second side surface located on the radially outer peripheral side of the disk rotor, and the friction surface of the disk rotor. and a slit extending between the first side and the second side in the face. Thus, the slit may extend along the radial direction of the disk rotor. The width of the slit measured along the circumferential direction of the disk rotor may increase from the radially inner side to the outer side of the disk rotor. The width of the slit may increase monotonously from the radially inner side to the outer side of the disk rotor, for example, it may increase continuously, and may increase so as to include a portion with a constant width. good too.

The friction material of the above embodiment may further have a pair of slit side surfaces that define the slit and face each other in the circumferential direction of the disk rotor. Each of the pair of slit side surfaces may be parallel to the radial direction of the disk rotor. In this example, the width of the slit continuously increases from the radially inner side to the outer side of the disk rotor. Therefore, the abrasion powder entering the slit is efficiently discharged from the slit.

When each of the pair of slit side surfaces is parallel to the radial direction of the disk rotor, the friction material includes a third side surface located at one end in the circumferential direction of the disk rotor and a third side surface located at one end in the circumferential direction of the disk rotor. and a fourth side located at the other end. Both the third side surface and the fourth side surface may be parallel to the radial direction of the disk rotor. In this example, the width of the friction material measured along the circumferential direction of the disk rotor continuously increases from the radially inner side to the outer side of the disk rotor. As a result, the in-plane distribution of the frictional force acting on the friction material is made uniform, and uneven wear is suppressed.

The technology disclosed in the present specification will be described below with reference to an opposed caliper type disc brake device. However, the techniques disclosed herein are also useful for other types of disc brake devices.

As shown in FIG. 1, a disc brake device 1 is mounted on a vehicle for use, and is configured to apply a braking force to wheels rotatably supported by the vehicle. The disc brake device 1 includes a disc rotor 2, a caliper 3, a pair of pistons 4 and 6, and a pair of brake pads 10 and 20.

The disk rotor 2 is connected to the wheel and configured to rotate integrally with the wheel. The disk rotor 2 has a disk-like shape, and a pair of main surfaces function as friction surfaces.

The caliper 3 is arranged across the outer peripheral edge of the disc rotor 2 so as to sandwich a part of the pair of friction surfaces of the disc rotor 2 . The caliper 3 is configured to hold the pair of brake pads 10, 20 such that each of the pair of brake pads 10, 20 faces the corresponding one of the pair of friction surfaces of the disc rotor 2. there is

Each of the pair of pistons 4 , 6 is arranged in a corresponding cylinder bore 8 , 9 of the pair of cylinder bores 8 , 9 formed in the caliper 3 . The piston 4 is provided so as to be slidable in the cylinder bore 8 along the rotation axis direction of the disc rotor 2 . The piston 4 is configured to press the brake pad 10 toward the friction surface of the disc rotor 2 according to the supplied hydraulic pressure. The piston 6 is provided so as to be slidable in the cylinder bore 9 along the rotation axis direction of the disc rotor 2 . The piston 6 is configured to press the brake pad 20 toward the friction surface of the disc rotor 2 according to the supplied hydraulic pressure. In this example, one piston is arranged corresponding to each of the pair of friction surfaces of the disc rotor 2, but a plurality of pistons may be arranged corresponding to each of the pair of friction surfaces. .

Each of the pair of brake pads 10, 20 is a friction member provided so as to face the corresponding one of the pair of friction surfaces of the disc rotor 2, and comprises friction materials 10a, 20a and back plates 10b, 10b. and have The brake pad 10 is an inner pad that faces the friction surface of the disc rotor 2 on the inner side of the vehicle, and the brake pad 20 is an outer pad that faces the friction surface of the disc rotor 2 on the outer side of the vehicle. In this embodiment, the brake pad 10, which is the inner pad, and the brake pad 20, which is the outer pad, have the same shape. Instead of this example, the shapes of the brake pads 10 and 20 may be appropriately adjusted so that desired friction performance is exhibited. The brake pad 10 will be described below, and the description of the brake pad 20 will be omitted.

The friction material 10a is arranged on the side facing the friction surface of the disk rotor 2, and is a member for applying a braking force when contacting the friction surface. The back plate 10b is a plate-like member that supports the friction material 10a and receives the pressing force from the piston 4. As shown in FIG.

As shown in FIGS. 2 and 3, the friction material 10a has a front surface 18 facing the friction surface of the disk rotor 2 and a back surface 19 opposite to the front surface 18 and in contact with the back plate 10b. doing. Friction material 10a further includes first side 11, second side 12, third side 13 and fourth side 14 extending between front surface 18 and rear surface 19. As shown in FIG. The first side surface 11 is a surface located radially inwardly of the disk rotor 2 and extends curvedly along the circumferential direction of the disk rotor 2 . The second side surface 12 is a surface located on the radially outer peripheral side of the disk rotor 2 and extends curvedly along the circumferential direction of the disk rotor 2 . The third side surface 13 is a surface located at one end in the circumferential direction of the disk rotor 2 and extends parallel to the radial direction of the disk rotor 2 . The fourth side surface 14 is located at the other circumferential end of the disk rotor 2 and extends parallel to the radial direction of the disk rotor 2 . Here, the radial direction of the disk rotor 2 is any direction perpendicular to the rotation axis RA of the disk rotor 2 .

A slit 15 is provided in the front surface 18 of the friction material 10a. A slit 15 extends between the first side 11 and the second side 12 so as to divide the front surface 18 of the friction material 10a into two halves. In this example, the slit 15 is formed by a thin portion of the friction material 10a. Instead of this example, the slit 15 may be configured to pass through the friction material 10a (see FIG. 4). Although only one slit 15 is provided in these examples, a plurality of slits may be provided.

The friction material 10 a further has a pair of slit side surfaces 16 and 17 that define the slit 15 and face each other in the circumferential direction of the disk rotor 2 . The first slit side surface 16 extends parallel to the radial direction of the disk rotor 2 . Similarly, the second slit side surface 17 also extends parallel to the radial direction of the disc rotor 2 .

A width W1 of the slit 15 measured along the circumferential direction of the disk rotor 2 is configured to increase from the radially inner side of the disk rotor 2 toward the outer side. In this example, since each of the pair of slit side surfaces 16 and 17 extends parallel to the radial direction of the disk rotor 2, the width W1 of the slit 15 is is configured to increase continuously towards Therefore, the width W1 of the slit 15 is the minimum width at the first side surface 11 and the maximum width at the second side surface 12 .

Next, features of the friction material 10a of the brake pad 10 will be described with reference to FIG. The disc brake device 1 generates a braking force by pressing the friction material 10 a against the friction surface of the disc rotor 2 . For example, when the disk rotor 2 rotates clockwise, abrasion powder generated by friction between the friction material 10a present on the right side of the slit 15 in the drawing and the disk rotor 2 flows into the slit as the disk rotor 2 rotates. Enter 15. Similarly, when the disk rotor 2 rotates counterclockwise, for example, abrasion powder generated by friction between the friction material 10a present on the left side of the slit 15 and the disk rotor 2 is It enters the slit 15 along with. Furthermore, the slit 15 extends between the first side surface 11 and the second side surface 12 and communicates with the outside. Therefore, the abrasion powder entering the slit 15 is discharged from the slit 15 to the outside. In particular, since the width W1 of the slit 15 is configured to continuously increase from the radially inner side to the outer peripheral side of the disc rotor 2, the abrasion powder entering the slit 15 is pushed out by centrifugal force. 15 to the outside efficiently. When the slits 15 are provided in the friction material 10a in this way, it is possible to prevent abrasion powder from remaining between the disc rotor 2 and the friction material 10a, thereby suppressing a decrease in frictional characteristics and uneven wear.

In the friction material 10 a , each of the third side surface 13 , the fourth side surface 14 , and the pair of slit side surfaces 16 and 17 extends parallel to the radial direction of the disk rotor 2 . Therefore, the width W2 of the friction material 10a measured along the circumferential direction of the disc rotor 2 is configured to continuously increase from the radially inner side to the outer side of the disc rotor 2. . Although only the portion on the right side of the slit 15 is shown as the width W2 of the friction material 10a, since the portion on the left side of the slit 15 has a symmetrical structure, the entire width of the friction material 10a is also It is configured to continuously increase from the inner peripheral side to the outer peripheral side in the radial direction of the disk rotor 2 . The width of the friction material 10a referred to here is the width measured at the portion of the disc rotor 2 in direct contact.

Here, the peripheral speed in the friction surface of the disk rotor 2 is faster on the outer peripheral side than on the inner peripheral side in the radial direction. As described above, the width W2 of the friction material 10a is configured to continuously increase from the radially inner side of the disk rotor 2 toward the outer peripheral side. That is, the friction material 10a has a shape such that its width W2 increases in accordance with the circumferential speed within the friction surface of the disk rotor 2. The shape is represented by a linear function with speed as an independent variable. As a result, the in-plane distribution of the frictional force acting on the friction material 10a is made uniform, and the amount of wear at any position on the friction material 10a is made uniform. As a result, uneven wear of the friction material 10a is suppressed.

Although specific examples of the technology disclosed in this specification have been described above in detail, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims as filed. The techniques exemplified in this specification or drawings can achieve a plurality of purposes at the same time, and achieving one of them has technical utility in itself.

1: Disc brake device 2: Disc rotor 3: Caliper 4, 6: Piston 10, 20: Brake pad 10a, 20a: Friction material 10b, 20b: Back plate 11: First side surface 12: Second Side 13: Third Side 14: Fourth Side 15: Slit 16: First Slit Side 17: Second Slit Side 18: Front 19: Rear 20: Brake Pad 20a: Friction material

Claims (3)

a brake pad,
a friction material facing the friction surface of the disk rotor,
The friction material is
a first side surface positioned radially inwardly of the disk rotor;
a second side surface positioned radially outwardly of the disk rotor;
a slit extending between the first side surface and the second side surface in a surface of the disk rotor facing the friction surface;
The brake pad, wherein the width of the slit measured along the circumferential direction of the disc rotor increases from the radially inner side to the outer side of the disc rotor. The friction material is
a pair of slit side surfaces that define the slit and face each other in the circumferential direction of the disk rotor,
2. The brake pad according to claim 1, wherein each of said pair of slit side surfaces is parallel to the radial direction of said disc rotor. The friction material is
a third side surface positioned at one end in the circumferential direction of the disk rotor;
a fourth side surface located at the other end in the circumferential direction of the disk rotor,
3. The brake pad according to claim 2, wherein both said third side surface and said fourth side surface are parallel to the radial direction of said disc rotor.

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