JP2001234954A - Pad for disc brake - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pad for disc brake capable of suppressing the squeaking in braking operation. SOLUTION: At least a pair of section parts in the disc rotor radial direction including through holes 15 and 16 provided in a rear plate 11 in which the ratio of the through hole area to the sum of the rear plate area and through hole area is over 40% are provided symmetrically about the center line of the rear plate 11 in the disc rotor circumferential direction. That through hole located on the turn-in side of the disc rotor is arranged confronting that end of the pad pressing surface 17 of piston 13 which is located on the turn-in side of disc rotor so that the flexural rigidity of the rear plate 11 at the end on the turn-in side of the disc rotor against the load in the disc rotor axial direction applied to the rear plate 11 from the piston is lessened, which allows avoiding the unfavorable increase of the surface contacting pressure of the friction material 12 at its end on the turn-in side of the disc rotor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art One of the causes of a brake squeal phenomenon that often occurs in a disc brake is warpage of a pad due to thermal expansion accompanying a rise in temperature. That is, when the temperature is increased to nearly 200 degrees Celsius by performing a severe braking action, the pad warps due to thermal expansion as shown in FIG. 11, and the friction surface of the pad becomes convex with respect to the side surface of the disk rotor. When a braking action is performed in this state, the surface pressure at the center of the friction surface in the circumferential direction of the disk rotor becomes higher than the surface pressure at the disk rotor entrance side end and the surface pressure at the disk rotor exit side end. The amount of wear at the center of the material in the circumferential direction of the disk rotor became larger than the amount of wear at the disk rotor entry side end and the amount of wear at the disk rotor exit side end, and then the braking action was terminated and the pad cooled. In this state, the friction surface of the pad becomes concave with respect to the disk rotor side surface. Therefore, when the braking action is performed again, the surface pressure at the end of the friction surface on the disk rotor entry side becomes large, which promotes vibration input and causes brake squeal.

In order to suppress the brake squeal phenomenon caused by the warpage of the pad due to the thermal expansion due to the temperature rise, it is necessary to warp the pad in advance as shown in FIG.
No. 29140.

[0004]

However, the above-mentioned prior art has problems such as the continuity of the effect when the wear of the friction material progresses and an increase in the amount of liquid consumed for operating the pad pressing member. Hard to say practical.

An object of the present invention is to provide a disc brake pad which solves the above-mentioned problem.

[0006]

According to the present invention, a friction material is fixed to a front surface of a metal back plate by molding, and the back plate is formed of a friction material. In a disc brake pad having a through hole filled with a friction material at the time of molding, a through hole corresponding to the sum of the area of the back plate and the area of the through hole is a radial cross-sectional portion including the through hole of the back plate. At least one pair of disk rotor radial cross-sections having an area ratio of 40% or more is symmetrically arranged with respect to the center line of the back plate in the disk rotor circumferential direction. A pad for a disc brake, which is arranged so as to face an end of a pad pressing surface of a pad pressing member on a disk rotor reciprocating side.

In such a disk brake pad, a disk is a disk rotor radial cross section including a through hole in the back plate, and a ratio of the through hole area to the sum of the back plate area and the through hole area is 40% or more. At least one pair of pairs of the rotor radial cross sections are symmetrically arranged with respect to the center line of the back plate in the circumferential direction of the disk rotor, and the through hole on the disk rotor reciprocating side has a disk pressing surface of the pad pressing member of the pad pressing member. By being arranged so as to oppose the inflow side end, the bending rigidity of the back plate with respect to the load in the axial direction of the disk rotor is reduced. Therefore, due to the warpage of the pad due to the thermal expansion accompanying the temperature rise, the center of the friction material in the circumferential direction of the disk rotor wears more than the disk rotor entrance side end and the disk rotor exit side end, and the friction surface of the pad is reduced. Even if it becomes concave with respect to the side surface of the disk rotor, an undesired increase in the surface pressure of the friction material at the disk rotor entry side end is avoided, and the occurrence of the brake squeal phenomenon is suppressed. And because it is not affected by the progress of wear of the friction material,
The occurrence of the brake squeal phenomenon can exhibit the effect of suppressing over a long period of time, and the amount of liquid consumed for operating the pad pressing member does not increase.

The pad pressing member is generally a claw portion of a hydraulically operated piston or movable cylinder. It is preferable that the through hole on the disk rotor outlet side is opposed to the disk rotor outlet side end of the pad pressing surface of the pad pressing member.
Further, the radial cross section of the disk rotor may be added to the center of the back plate in the circumferential direction of the disk rotor.

[0009]

FIG. 1 is a view showing the relationship between a disc brake pad according to a first embodiment of the present invention and a disc rotor and a piston, FIG. 2 is a rear view of the pad, and FIG. 3 is FIG. FIG. 4 is a sectional view taken along line AA of FIG. The disc brake pad 10 is formed by fixing a friction material 12 to a front surface of a steel plate back plate 11 by molding, and is pressed against a side surface of a disc rotor 14 by a hydraulically operated piston 13. The disk rotor 14 usually rotates in the direction of the arrow. When used as a vehicle wheel brake, the disk rotor 14 rotates in the direction of the arrow when the vehicle is moving forward.

Through holes 15 and 16 are formed in the back plate 11, and these through holes are filled with a friction material 12 molded. The through holes 15 and 16 are formed symmetrically with respect to the center O-O in the disk rotor circumferential direction, and are formed in an elliptical shape whose major axis is the disk rotor radial direction. In the disk rotor radial section AA including the through hole 15 and the disk rotor radial section AA including the through hole 16 of the back plate 11, the back plate areas S1, S2
And the ratio of the through-hole area S3 to the sum of the through-hole area S3 is 40.
%. The ratio of the through-hole area S3 to the sum of the back-plate areas S1, S2 and the through-hole area S3 is desirably as large as possible within the range where the required strength of the back plate 11 is satisfied in order to suppress the brake squeal phenomenon. The through-hole 15 is the end 1 of the pad pressing surface 17 of the piston 13 (shown hatched in FIG. 2) on the disk rotor reciprocating side.
Opposite to 7 a, the end 17 a of the pad pressing surface 17 on the disk rotor entry side covers and covers about half of the through hole 15. The through hole 16 is opposed to the disk rotor outlet side end 17 b of the pad pressing surface 17, and the disk rotor outlet side end 17 b of the pad pressing surface 17 covers and covers about half of the through hole 16. Due to the existence of the through hole 15, the bending rigidity of the end of the back plate 11 on the disk rotor entry side with respect to the load in the disk rotor axial direction applied to the back plate 11 from the piston 13
It is lower than the case where the through hole 15 does not exist. Therefore,
An undesired increase in the contact pressure at the end of the friction material 12 on the disk rotor entry side is avoided. Due to the presence of the through hole 16, the bending rigidity of the disk rotor outlet side end of the back plate 11 with respect to the axial load applied to the back plate 11 from the piston 13 is lower than that in the case where the through hole 16 does not exist. Become. Therefore, an undesired increase in the surface pressure of the friction material 12 at the disk rotor entry side end can be avoided even when the vehicle moves backward.

FIG. 4 is a diagram showing the relationship between a disc brake pad according to a second embodiment of the present invention and the claws of a disc rotor and a movable cylinder. FIG. 5 is a rear view of the pad. In the back plate 21 of the pad 20, the through hole 1 shown in FIG.
Through holes 25 and 26 corresponding to 5 and 16 are formed.
The through holes 25 and 26 face the disk rotor circumferential ends 120a and 120b of the pressing surface 120 (shown by hatching in FIG. 5) of the claw portion 19 of the movable cylinder 18. In FIG. 4, reference numeral 22 denotes a friction material.

FIG. 6 shows a third embodiment of the pad. In the back plate 31 of the pad 30 of FIG.
6 and an oval through hole 37 located at the center of the back plate 31 in the disk rotor circumferential direction. Through hole 37 at the center in the circumferential direction of the disk rotor on the back plate
Is for tuning the vibration mode of the pad according to the brake squeal frequency that is likely to occur.

FIG. 7 shows a fourth embodiment of the pad. The through holes 35, 3 in FIG. 6 of the back plate 41 of the pad 40 in FIG.
The through holes 45, 46, 47 corresponding to 6, 37 are formed as long holes.

FIG. 8 shows a fifth embodiment of the pad. In the back plate 51 of the pad 50 in FIG. 8, two circular through holes 55A and 55B corresponding to the through hole 15 in FIG. 2 and two circular through holes corresponding to the through hole 16 in FIG. 56A and 56B are formed.

FIG. 9 shows a sixth embodiment of the pad. In the back plate 61 of the pad 60 in FIG. 9, two circular through holes 65A and 65B corresponding to the through hole 35 in FIG. 6, and two circular through holes 36 corresponding to the through hole 36 in FIG. 66A and 66B and two circular through holes 67A and 67 corresponding to the through holes 36 in FIG.
B is formed.

FIG. 10 shows a seventh embodiment of the pad. The back plate 71 of the pad 70 of FIG.
Four circular through holes 75A, 75B, 76A, 76B corresponding to A, 55B, 56A, 56B are formed,
The distance between the through holes 75A and 76A in the circumferential direction of the disk rotor is different from the distance between the through holes 75B and 76B in the circumferential direction of the disk rotor. The distance between the through holes 75A and 76A in the disk rotor circumferential direction may be larger than the distance between the through holes 75B and 76B in the disk rotor circumferential direction, and vice versa. It may be larger than the disk rotor circumferential interval of 76A.

[0017]

As described above, the disc brake pad according to the invention of the present application is a radial cross section of the disc rotor including the through hole of the back plate, and the sum of the back plate area and the through hole area. And at least one pair of disk rotor radial cross-sections having a ratio of through hole area to 40% or more with respect to the center line of the back plate in the circumferential direction of the disk rotor. Since the through holes are arranged so as to face the end of the pad pressing surface of the pad pressing member facing the disk rotor, the bending rigidity of the back plate with respect to the load in the axial direction of the disk rotor is reduced. Therefore, due to the warpage of the pad due to the thermal expansion accompanying the temperature rise, the center of the friction material in the circumferential direction of the disk rotor wears more than the disk rotor entrance side end and the disk rotor exit side end, and the friction surface of the pad is reduced. Even if it becomes concave with respect to the side surface of the disk rotor, an undesired increase in the surface pressure of the friction material at the disk rotor entry side end is avoided, and the occurrence of the brake squeal phenomenon is suppressed. And since it is not affected by the progress of the wear of the friction material, the generation of the brake squeal phenomenon can be suppressed for a long period of time, and the amount of liquid consumed for operating the pad pressing member does not increase.

[Brief description of the drawings]

FIG. 1 is a diagram showing a relationship between a disc brake pad according to a first embodiment of the present invention and a disc rotor and a piston.

FIG. 2 is a rear view of the pad of FIG. 1;

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a diagram showing a relationship between a disc brake pad according to a second embodiment of the present invention and a claw portion of a disc rotor and a movable cylinder.

FIG. 5 is a rear view of the pad of FIG. 5;

FIG. 6 is a view showing a third embodiment of the disc brake pad according to the invention of this application.

FIG. 7 is a view showing a disc brake pad according to a fourth embodiment of the present invention;

FIG. 8 is a diagram showing a fifth embodiment of the disc brake pad according to the invention of this application.

FIG. 9 is a view showing a sixth embodiment of the disc brake pad according to the invention of this application.

FIG. 10 is a view showing a disc brake pad according to a seventh embodiment of the present invention.

FIG. 11 is a view showing warpage of a pad due to thermal expansion accompanying a temperature rise.

[Explanation of symbols]

 10, 20, 30, 40, 50, 60, 70: pad 11, 21, 31, 41, 51, 61, 71: back plate 12, 22: friction material 13: piston 14. ..Disk rotor 17: Pad pressing surface 15, 16: Through hole

Claims (1)

[Claims] A pad for a disc brake, wherein a friction material is fixed to a front surface of a metal back plate by molding, and a through hole is formed in the back plate to be filled with the friction material during molding of the friction material. The pair of disk rotor radial cross-sections including the through holes of the back plate and having a ratio of the through-hole area to the sum of the back plate area and the through-hole area of 40% or more is a back side. At least one pair is provided symmetrically with respect to the center line of the plate in the circumferential direction of the disk rotor, so that the through hole on the disk rotor entry side faces the disk rotor entry side end of the pad pressing surface of the pad pressing member. A pad for a disc brake, wherein the pad is arranged on a pad.