JP2002250372A - Disc brake - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively reduce brake noise after securing the rigidity of a shim plate by suppressing the cutout amount of the shim plate to a required minimum in the disc brake. SOLUTION: In this disc brake provided with the shim plate 60 between the rear face of a pad 50 and a piston 15, the pad 50 is formed into a long shape in the rotor peripheral direction, a pair of mold holes 52a separated wid a prescribed distance in the rotor peripheral direction are provided on the back plate 52, the piston 15 has an annular pressing surface 15a superposing partially on both of the mold holes 52a and the shim plate 60 has a cutout 61 cut partially at an abutting portion with the piston 15. A part 15a1 of the annular pressing surface 15a of the piston 15 reduces a pressing area S1 for pressing the rear face of the back plate 52 via the shim plate 60 by the cutout 61 in the range of 50% to 75%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc brake, in particular, a piston mounted on a caliper, and a pad pushed by the piston toward a disc rotor.
The present invention relates to a disc brake having a shim plate which is mounted on the back side of the pad and interposed between the pistons.

[0002]

2. Description of the Related Art In this type of disc brake,
As a countermeasure against brake squeal, there is a method in which a predetermined notch is provided in the shim plate to adjust the surface pressure distribution when the piston presses the pad via the shim plate (during braking). -101281.

[0003]

In the disc brake disclosed in the above-mentioned publication, the reduction in rigidity due to the notch in the shim plate is caused by a locking claw (a portion attached to a pad back plate formed on the shim plate). Separately, a bent portion is newly provided for the countermeasures, so that the cost increase accompanying the new bent portion is inevitable. Further, since the shim plate is formed in an asymmetric shape with respect to the center in the circumferential direction of the rotor, when the disc brake is used in a pair of right and left, a shim plate having a different shape on the left and right is required, thereby increasing costs. Or erroneous assembly.

[0004]

According to the present invention, a piston mounted on a caliper, a pad pushed toward a disk rotor by the piston, and a pad of the pad are provided. In a disc brake having a shim plate interposed between the pistons, the pad is formed in a shape elongated in the circumferential direction of the rotor, and a pair of the pads are separated from the back plate by a predetermined amount in the circumferential direction of the rotor. A configuration in which the piston has an annular pressing surface that partially overlaps with both the mold holes, and the shim plate has a notch that is partially cut out at a contact portion with the piston. The pressing area in which a part of the annular pressing surface of the piston presses the back surface of the back plate via the shim plate is reduced by the notch in a range of 50% to 75%. It is characterized in that the invention).

[0005] In order to solve the above-mentioned former and latter problems, in addition to the above-mentioned features, in addition to displacing the axial center of the piston relative to the center of the pad in the rotor circumferential direction by a predetermined amount in the rotor circumferential direction. The invention is characterized in that the shim plate is formed in a line-symmetrical shape with respect to the center in the circumferential direction of the rotor (the invention according to claim 2).

[0006]

In the disc brake according to the present invention (the invention according to claim 1), a part of the annular pressing surface of the piston presses the back surface of the back plate via the shim plate (the pressing area provided on the back plate). The pressing area of one of the four divided by the pair of mold holes is reduced in the range of 50% to 75% by the notch of the shim plate, and the notch amount of the shim plate is minimized. Since the shim plate at the portion corresponding to the mold hole is left while being suppressed, brake squeal can be effectively reduced as shown in FIG. 6 while securing the rigidity of the shim plate. In addition, since it can be achieved by a method of changing the notch amount of the shim plate, that is, a change in an existing processing step for forming a notch in the shim plate, it can be implemented at low cost.

Further, in the disk brake according to the present invention (the invention according to claim 2), in addition to the above-described features, the axial center of the piston is displaced by a set amount in the rotor circumferential direction with respect to the center of the pad in the rotor circumferential direction. In addition, since the shim plate is formed in a line-symmetrical shape with respect to the center in the circumferential direction of the rotor, the effect of the invention according to claim 1 described above can be obtained, and the disk brakes can be paired on the left and right. Even when used, shims with the same shape can be used on the left and right sides, and the shims can be shared, eliminating the cost of shims and the cause of incorrect assembly. be able to.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. 1 to 6 show a vehicle disk brake A (a disk brake mounted on the right side of the vehicle) according to the present invention. In this disk brake A, a caliper 10 has a pair of arms 11 and 12 at both ends thereof. Are supported by both support portions 21 and 22 of the mounting 20 via pin slide means (not shown) so as to be slidable in the rotor axial direction. Note that the caliper 10 and the mounting 20 are formed so as to straddle the disk rotor 30. The disc rotor 30 rotates clockwise in FIG. 1 when the vehicle advances.

The caliper 10 has an outer pad 40 facing the disk rotor 30 and a shim plate 6 common to the outer and inner members.
The outer side has an arch-shaped reaction force arm 13 that presses through the inner side of the arm, and the inner side has both arms 11, 12 and a bottomed cylinder inner hole. The cylinder bore 14 is
A piston 15 that opens toward the disk rotor 30 and presses the inner pad 50 toward the disk rotor 30 via a shim plate 60 is provided inside the seal ring 1.
6 so as to be slidable in the axial direction of the rotor.
A boot 17 is attached between the open end of the cylinder bore 14 and the outer periphery of the protruding portion of the piston 15. The outer pad 40 and the inner pad 50 are supported by the mounting 20 so as to be slidable in the rotor axis direction.

[0010] As shown in FIG. 2, the piston 15 is formed in a cylindrical shape with a bottom, and a shim plate 60 with an inner pad 50 facing the disk rotor 30 is provided at an open end protruding from the cylinder inner hole 14. It has an annular pressing surface 15a for pressing through. As shown in FIGS. 1 and 2, the piston 15 has its axial center O1 set in the rotor circumferential direction with respect to the center of the pads 40, 50 in the rotor circumferential direction (see the center line L1 in FIG. 1). It is provided with a δ displacement (offset). As shown in FIGS. 1 to 3, the reaction force arm 13, like the piston 15, has its center in the rotor circumferential direction (see the center line L <b> 2 in FIGS. 1 and 3) as the rotor of both pads 40, 50. It is provided in a state displaced by a set amount δ in the rotor circumferential direction with respect to the circumferential center (L1).

As shown in FIG. 2, the outer pad 40 can be slidably contacted with the disk rotor 30, and as shown schematically in FIG. 3, the length in the rotor circumferential direction is smaller than the length in the rotor radial direction. A friction material 41 formed in a long shape, and a back plate 42 provided integrally with the rear surface of the friction material 41 and pressed by the reaction force arm 13 via the shim plate 60,
The back plate 42 has a pair of mold holes spaced apart by a predetermined amount in the circumferential direction of the rotor.
In the figure, a through-hole 42a indicated by a solid line is formed. Each mold hole 42a is for a friction material 41 formed by molding, and is set so that the friction material 41 does not protrude from the rear side of the mold hole 42a.

As shown in FIG. 2, the inner pad 50 can be slidably contacted with the disk rotor 30. As schematically shown in FIG. 4, the length in the circumferential direction of the rotor is smaller than the length in the radial direction of the rotor. And a back plate 52 integrally provided on the back surface of the friction material 51 and pressed by the annular pressing surface 15a of the piston 15 via the shim plate 60. A pair of mold holes 52a (through holes which are covered with the shim plate 60 in the assembled state, but are shown by solid lines in FIG. 4) 52a are formed in the 52 at a predetermined distance in the rotor circumferential direction. Each mold hole 52a is for the friction material 51 formed by molding,
It is configured to partially overlap with the annular pressing surface 15a of the piston 15, and is set so that the friction material 51 does not protrude from the rear side of the mold hole 52a.

As shown in FIG. 5, each shim plate 60 is formed symmetrically with respect to the center in the circumferential direction of the rotor (see the center line L3 in FIG. 5), and as shown in FIG. It has a notch 61 that is partially cut out at a contact portion with the piston 15. In each shim plate 60, the notch 61 causes a portion 15 a 1 of the annular pressing surface 15 a of the piston 15 to pass through the shim plate 60 through the back plate 52 of the inner pad 50.
The pressing area S1 (one pressing area divided into four by a pair of mold holes 52a provided on the back plate 52) for pressing the back surface of the substrate is reduced in the range of 50% to 75%. Thereby, the surface pressure distribution of the pressing force by the piston 15 is adjusted.

That is, when the notch 61 is not formed in the shim plate 60 (see the phantom line in FIG. 5), the annular pressing surface 15a
Of the inner pad 5 via the shim plate 60
0, the above-mentioned pressing area S1 is 50% to 75% of a virtual pressing area So for pressing the back surface of the back plate 52.
And is set to an appropriate value in the range of So / 2 to So / 4. The other parts 15a2, 15a3, 1 of the annular pressing surface 15a of the piston 15
Pressing areas S2, S3, S4 for pressing the back surface of the back plate 52 on the inner pad 50 via the shim plate 60
Is appropriately set to a value larger than the above-described pressed area S1. The pressing areas S11 and S12 where the reaction arm 13 presses the back surface of the back plate 42 of the outer pad 40 via the shim plate 60 are as shown in FIG.

In this embodiment constructed as described above, the piston 15 moves the inner pad 50 via the shim plate 60 to the disk rotor 30 during braking while the disk rotor 30 is rotating (the running state of the vehicle). 30, the reaction force arm 13 of the caliper 10 presses the outer pad 40 toward the disk rotor 30,
As the outer pad 40 and the inner pad 50 sandwich the disk rotor 30, the disk rotor 30 is braked.

In this embodiment, a part 15a1 of the annular pressing surface 15a of the piston 15 is
The pressing area S1 for pressing the back surface of the back plate 52 through the cutout 62 is reduced by a notch 62 in a range of 50% to 75%. Since the shim plate 60 at the corresponding portion is left, the brake squeal can be effectively reduced as shown in FIG. 6 while securing the rigidity of the shim plate 60. Moreover, since this can be achieved by a method of changing the notch amount of the shim plate 60, that is, a change in an existing processing step for forming the notch 61 in the shim plate 60, it can be implemented at low cost. 6A and 6B show that the reduction rate of the pressed area S1 is 0%, 50%, 75%.
% And 80%, and show the squealing rate when the low load braking test and the high load braking test are performed. From these, the reduction rate of the pressing area S1 is in the range of 50% to 75%. For example, it can be seen that the pass / fail judgment value is cleared in both the low load braking test and the high load braking test.

In this embodiment, both pads 4
The axial center O1 of the piston 15 is displaced by a set amount δ in the circumferential direction of the rotor with respect to the center (L1) of the rotor in the circumferential direction of 0, 50, and each shim plate 60 has a line-symmetric shape with respect to the center (L3) in the circumferential direction of the rotor. Since the disc brake is used in a pair of left and right,
The shim plate 60 having the same shape can be used for the left and right sides, and the shim plate 60 can be shared.
This can eliminate the cost increase and the factor of erroneous assembly.

In the above embodiment, both pads 40,
The piston 15 is located at the center (L1) of the rotor 50 in the circumferential direction.
The axial center O1 is displaced by a set amount δ in the rotor circumferential direction, and each shim plate 60 is formed in a line symmetrical shape with respect to the rotor circumferential center (L3). As shown in FIG. Although the axial center O1 of the piston 15 is displaced by a set amount δ in the rotor circumferential direction with respect to the rotor circumferential center (L1) of both pads 40 and 50, each shim plate 60 is moved with respect to the rotor circumferential center (L3). It is also possible to carry out without forming a symmetrical shape. In this case, a palm symmetrical shim plate is required.

Further, in the embodiment of FIG. 7, the axial center O1 of the piston 15 is displaced by a set amount δ in the rotor circumferential direction with respect to the rotor circumferential center (L1) of both pads 40, 50. As in the embodiment illustrated in FIG. 8, it is also possible to carry out the embodiment by aligning the axial center O1 of the piston 15 in the rotor circumferential direction with respect to the rotor circumferential center (L1) of both pads 40 and 50. In this case, the pressing areas S11 and S12 in which the reaction arm 13 presses the back surface of the back plate 42 of the outer pad 40 via the shim plate 60.
Is as shown in FIG.

In each of the above embodiments, a portion 15a1 of the annular pressing surface 15a of the piston 15 is
The pressing area S1 for pressing the back surface of the back plate 52 through the cutout 62 is reduced by a notch 62 in the range of 50% to 75%, but instead of this, another part of the annular pressing surface 15a of the piston 15 is replaced. Any one of the pressing areas S2, S3, and S4 in which 15a2, 15a3, and 15a4 press the back surface of the back plate 52 of the inner pad 50 via the shim plate 60 is reduced by cutout in the range of 50% to 75%. It is also possible to carry out.

[Brief description of the drawings]

FIG. 1 is a side view showing an embodiment of a disc brake according to the present invention.

FIG. 2 is a sectional view taken along line 2-2 of FIG.

FIG. 3 is a view showing a relationship between a reaction arm portion, a shim plate, and an outer pad shown in FIGS. 1 and 2;

FIG. 4 is a diagram showing a relationship between a piston, a shim plate, and an inner pad shown in FIGS. 1 and 2;

FIG. 5 is a front view of the shim plate shown in FIGS. 1 to 4;

FIG. 6 shows reduction rates of the pressing area S1 of 0%, 50%, and 75%.
5 is a diagram showing the squeal occurrence rate when performing a low-load braking test and a high-load braking test by changing to% and 80%. FIG.

FIG. 7 is a view corresponding to FIG. 4 and showing a modified embodiment of the disc brake according to the present invention.

FIG. 8 is a view corresponding to FIG. 4, showing another modified embodiment of the disc brake according to the present invention.

FIG. 9 is a view corresponding to FIG. 3 in the embodiment shown in FIG. 8;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Caliper, 11, 12 ... Arm part, 13 ... Reaction force arm part, 14 ... Cylinder bore, 15 ... Piston, 15a
... an annular pressing surface, 15a1 ... a part of an annular pressing surface, 16 ...
Seal ring, 20 mounting, 21, 22 support, 30 disk rotor, 40 outer pad, 4
DESCRIPTION OF SYMBOLS 1 ... Friction material, 42 ... Back plate, 42a ... Mold hole, 50 ...
Inner pad, 51: friction material, 52: back plate, 52a: mold hole, 60: shim plate, 61: notch, S1: pressing area, L1: center of pad in circumferential direction of rotor, L3: center of line symmetry of shim plate, O1: axial center of piston, δ: displacement set amount.

Claims (2)

[Claims] 1. A disk having a piston mounted on a caliper, a pad pushed by the piston toward a disk rotor, and a shim mounted on the back side of the pad and interposed between the pistons. In braking
The pad is formed in a shape that is long in the circumferential direction of the rotor, and has a pair of mold holes spaced apart by a predetermined amount in the circumferential direction of the rotor on a back plate thereof, and the annular pressing in which the piston partially overlaps with both the mold holes. Surface, and the shim plate has a notch partially cut out at a contact portion with the piston, and a part of the annular pressing surface of the piston is a rear surface of the back plate via the shim plate. A disc brake, characterized in that a pressing area for pressing is reduced in a range of 50% to 75% by the notch. 2. The disk brake according to claim 1, wherein the axial center of the piston is displaced by a predetermined amount in the rotor circumferential direction with respect to the rotor circumferential center of the pad, and the shim plate is moved to the rotor circumferential center. A disc brake characterized by being formed in a line symmetrical shape.