JP3082567B2 - Disc brake device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc brake device mounted on a vehicle such as an automobile.

[0002]

2. Description of the Related Art Disc brakes are used in braking systems of automobiles. A conventional floating type disk brake device 100 shown in FIG. 12 includes a disk rotor 101 as a rotating member and a fixed caliper unit 102.
It has. The disk rotor 101 is rigidly connected to the hub,
It is designed to rotate integrally with the wheels. The caliper unit 102 includes a torque member 105 fixed to the hub carrier of the suspension mechanism, and a caliper 106 that is movable relative to the torque member 105 in the axial direction of the disk rotor 101. The caliper 106 has a shape straddling the disk rotor 101, and a pad 11 is provided on the inner surface side of the caliper 106.
0 and 111 are retained. Caliper 106
Can move along a slide pin bolt 112 screwed into the torque member 105.

The pads 110 and 111 are opposed to the friction surfaces 115 and 116 of the disk rotor 101, and one pad 110 is configured to be pressed against the inner friction surface 115 of the disk rotor 101 by the piston 120. The piston 120 is housed in a cylinder chamber 121 provided in the caliper 106. A piston seal 122 is provided on the inner peripheral surface of the cylinder chamber 121. Reference numeral 123 denotes a dust boot. The other pad 111 is the inner wall 1 on the tip side of the caliper 106.
Backed by 25. One pad 110 and piston 1
Between them, shims 130 and 131 are provided. A shim 132 is also provided between the other pad 111 and the inner wall 125 on the distal end side of the caliper 106.

In the disk brake device 100, the piston 120 moves toward the disk rotor 101 by introducing the brake fluid pressure generated in the master cylinder into the cylinder chamber 121 according to the depression force of the brake pedal.
Thus, one pad 110 is pressed against the disk rotor 101 and the reaction force is transmitted to the caliper 106, so that the caliper 106 moves to a position where the other pad 111 contacts the disk rotor 101. Thus, since the disk rotor 101 is sandwiched between the pads 110 and 111, the disk rotor 101 is braked. When the brake fluid pressure is released, the piston 120 moves in the direction of the original position due to the elastic restoring force of the piston seal 122.
The pads 110 and 111 are separated from the disk rotor 101.

In the brake device 100, the pad 11
Occasional abnormal vibration (so-called brake squeal) may occur during braking, depending on the material of 0, 111, the shape of the friction surface, or the natural frequency. The brake squeal is caused by the leading side of the pads 110 and 111 (part contacting the rear side in the rotation direction of the disk rotor 101) especially when the brake fluid pressure is relatively low such as when the brake is applied.
Also, it is likely to occur in a portion corresponding to the vicinity of the inner peripheral portion of the disk rotor 101.

As a countermeasure for preventing the brake squeal, the shims 130 and 131 shown in FIG. 12 are formed by cutting off the portions 140 and 141 indicated by hatching, so that the side on which the brake squeal is less likely to occur is mainly the pads 110 and 111.
Has been proposed, and a certain effect has been achieved.

[0007]

However, when the portions 140 and 141 of the shim are cut off as in the above-described conventional example, when the pedaling force is large (when the brake fluid pressure is large),
Since the pressing force of the pads 110 and 111 is relatively smaller in the portions 140 and 141 than in the other portions, the contact of the pads 110 and 111 with the disk rotor 101 may become non-uniform. There was room for

Accordingly, it is an object of the present invention to provide a disc brake device which can prevent the occurrence of brake squeal during braking and can make the pressing force of the pad closer to equalization when the brake pedal pressure is large. is there.

[0009]

SUMMARY OF THE INVENTION The present invention, which has been developed to achieve the above object, comprises a disk rotor having friction surfaces on both sides, a pair of pads provided to face each friction surface of the disk rotor, and A caliper having a cylinder chamber in which the pad is held and brake fluid pressure is introduced inside the disc rotor, and a disc chamber provided in the cylinder chamber of the caliper, and the disc is provided in accordance with the brake fluid pressure; A disc brake device including a piston moving in the direction of the rotor, a first shim disposed between the one pad and the piston, and a second shim disposed on the other pad side, The shim is made of a plate material having spring properties, and a part of the shim is padded first on a side where brake squeal is unlikely to occur when the brake fluid pressure is low. It is characterized in that an elastic deformable convex portion to allow pressing the pad with substantially the entire shim by collapse in the thickness direction when pressurized and the brake fluid pressure is large.

[0010]

When the brake pressure is generated in the master cylinder by depressing the brake pedal, the brake fluid pressure corresponding to the depressing force is applied to the cylinder chamber of the caliper. The pad is pressed against the disk rotor by moving the piston by the hydraulic pressure. While the brake fluid pressure is low, the pad provided on the shim should be padded first from the part where brake squeal is unlikely to occur, such as the part corresponding to the trailing side of the shim or the vicinity of the outer periphery of the disk rotor. Press. When the brake fluid pressure increases, the convex portion is crushed in the thickness direction of the shim and the entire shim becomes substantially flat, so that a substantially uniform pressing force is applied to the pad under a certain level of pedaling force.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. The floating type disk brake device 10 shown in FIG. 2 includes a disk rotor 11 which is a member on the rotating side, and a caliper unit 12 on the fixed side. The disk rotor 11 is rigidly connected to a wheel-side hub (not shown), and rotates integrally with the wheel.

As shown in FIG. 1, the caliper unit 12
Has a torque member 15 fixed to the hub carrier of the suspension mechanism, and a caliper 16 movable relative to the torque member 15 in the axial direction of the disk rotor 11. The caliper 16 is shaped so as to straddle the disk rotor 11, and pads 20 and 21 are held on the inner surface side of the caliper 16. Caliper 1
Numeral 6 is movable in the axial direction of the disk rotor 11 along two slide pin bolts 22 provided on the torque member 15.

As shown in FIG.
1 comprises back metal 25, 26 and friction materials 27, 28, etc.
The friction members 27 and 28 face the inner friction surface 30 and the outer friction surface 31 of the disk rotor 11, respectively. As shown in FIG. 5 and the like, one pad 20 is pressed against the inner friction surface 30 of the disk rotor 11 by the piston 35. The other pad 2
1 is supported by the inner wall 36 on the distal end side of the caliper 16.

The piston 35 is housed in a cylinder chamber 40 provided in the caliper 16. Cylinder chamber 4
A brake pipe (not shown) is connected to 0 so that a brake fluid pressure generated in the master cylinder when the brake pedal is depressed is introduced into the cylinder chamber 40.

An elastically deformable rubber piston seal 45 is provided on the inner peripheral surface of the cylinder chamber 40. The inner peripheral surface of the piston seal 45 is slidably in contact with the outer peripheral surface of the piston 35 in the axial direction of the piston 35. When the piston 35 moves, the piston seal 45 is dragged in the moving direction of the piston 35 and elastically deforms, so that a force for returning the piston 35 is stored. A dust boot 46 is provided at the tip of the piston 35.

The back metal 25 of one pad 20 and the piston 3
5, a first shim 50 and an auxiliary shim 51 are provided. This shim 50 is, for example, SUS301CP, S
It is made of a heat-resistant stainless steel plate for a spring such as austenitic stainless steel such as US304CP. Auxiliary shim 51
Is considered so that the heat of the pad 20 is not easily transmitted to the piston 35 side. In addition, heat-resistant grease such as lithium is applied between the pad 20 and the shim 51 so as to reduce the natural frequency, thereby making it difficult for abnormal vibration to occur.

The back metal 26 of the other pad 21 and the caliper 1
A second shim 55 is provided between the inner wall 36 and the inner wall 36 on the tip side. The shim 55 is also made of the same heat-resistant spring material as the first shim 50, and the same heat-resistant grease as described above is applied between the pad 21 and the shim 55.

The trailing side of the shims 50 and 55, that is, the side that comes into contact with the rotating disk rotor 11 first (the part that comes into contact with the rear side in the rotation direction of the disk rotor 11)
Are provided with convex portions 60 and 61. These convex portions 6
Numerals 0 and 61 are obtained by cutting and raising a part of the shims 50 and 55 by pressing or the like, as shown in FIG. It can bend. In the case of the illustrated example, the cut and raised tip portions 62 and 63 are arranged in such a direction as to project toward the pads 20 and 21. The protrusion height H of the protrusions 60 and 61 is, for example, about 0.4 mm to 1.0 mm. Convex parts 60, 6
The portions other than 1 are almost flat.

Next, the disk brake device 10 having the above configuration
The operation of will be described. This disc brake device 1
0 means that when the brake fluid pressure is applied to the cylinder chamber 40,
When the piston 35 moves in the direction of the disk rotor 11, one pad 20 is pressed against the inner friction surface 30 of the disk rotor 11. Then, since the reaction force acts on the caliper 16, the caliper 16 moves to a position where the pad 21 on the opposite side contacts the outer friction surface 31 of the disk rotor 11.

In the brake device 10, the shim 5
Since the projections 60 and 61 are cut and raised in a part of the cylinders 0 and 55, when the piston 35 moves in the direction of the disk rotor 11 by the brake fluid pressure, the pad is formed by the projections 60 and 61 while the brake fluid pressure is small. 20 and 21 are mainly pressed on the trailing side. That is, as shown in FIG. 8, while the pedaling force is small, the trailing side where the brake squeal is unlikely to occur is pressed first, so that the brake squeal is reduced.

When the brake pressure increases due to an increase in the pedaling force,
Since the pressing force by the piston 35 increases, the convex portions 60,
When the protrusion 61 is elastically deformed in the direction in which the
0, 61 becomes the same level as the thickness of the shims 50, 55,
The shims 50 and 55 become almost flat. Therefore, under a certain level of pedaling force, the entire shim presses the pads 20 and 21. That is, when the brake fluid pressure is high, the surface pressures of the pads 20 and 21 on the disk rotor 11 are nearly equal, and uneven wear of the pads 20 and 21 is prevented. Since the disk rotor 11 is sandwiched between the pads 20 and 21 in this manner, the rotation of the disk rotor 11 is braked by the friction generated between the disk rotor 11 and the pads 20 and 21.

When the brake fluid pressure is released, the cylinder chamber 4
As the hydraulic pressure of 0 decreases, the piston 35 is returned to the original direction by the elastic restoring force of the piston seal 45, so that the pads 20, 21 are separated from the disk rotor 11. At the time of decompression, the convex portions 60 and 61 return to the original state by their own elastic restoring force, so that brake squeal is also suppressed at the time of decompression.

When the brake fluid is depressurized, the piston 35 returns by the restoration stroke of the piston seal 45, so that the piston 35 always returns by a fixed amount regardless of the wear amount of the pads 20, 21. Therefore, the piston seal 45 is formed between the disk rotor 11 and the pads 20, 21.
And also serves as a clearance adjusting means for automatically adjusting the gap between them.

FIGS. 9 to 11 show a second embodiment of the present invention. In the case of the disc brake device 70 of this embodiment,
The outer periphery of the shims 71 and 72, that is, the disk rotor 1
Convex portions 73 and 74 protrude at positions corresponding to the vicinity of the outer peripheral portion 1. The other configuration is the same as that of the first embodiment, and the same reference numerals are given to the same parts as those of the first embodiment, and the description will be omitted.

In the case of the second embodiment, when the pedaling force (brake fluid pressure) is small, the cut-and-raised tips 75 and 76 of the projections 73 and 74 are applied to the pads 20 and 21 first from the outer peripheral side of the disk rotor 11. This is effective in preventing brake squeal when abnormal vibration is likely to occur near the inner peripheral portion of the pads 20, 21 due to the material of the pads 20, 21 and the shims 71, 72, the shape of the friction surface, or the natural frequency. There is. Also in this case, when the brake fluid pressure is large,
When the shims 71 and 72 are crushed in the thickness direction of the shims 71 and 72, the pads 20 and 21 are pressed by the entire shim.
Uneven surface pressure is avoided.

[0026]

According to the present invention, it is possible to prevent the occurrence of brake squeal when the pedaling force at the time of braking is small, and when the pedaling force is large, almost the entire pad can exert a pressing force that is almost equal. Uneven wear can be avoided. Further, the convex portion can be easily obtained by cutting a part of the shim, and the number of parts does not increase.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a disc brake device showing one embodiment of the present invention.

FIG. 2 is a perspective view showing a state where the disc brake device shown in FIG. 1 is assembled.

FIG. 3 is a front view showing pads and shims of the disc brake device shown in FIG. 1;

FIG. 4 is a side view of the disc brake device shown in FIG. 1;

FIG. 5 is a sectional view taken along the line VV in FIG. 4;

FIG. 6 is a plan view of a shim of the disc brake device shown in FIG. 1;

FIG. 7 is a sectional view taken along the line VII-VII in FIG. 6;

FIG. 8 is a diagram showing the relationship between the pedaling force and the pressing force of the disc brake device shown in FIG.

FIG. 9 is an exploded perspective view of a disc brake device showing another embodiment of the present invention.

FIG. 10 is a plan view of the shim of the disc brake device shown in FIG. 9;

FIG. 11 is a sectional view along XI-XI in FIG. 10;

FIG. 12 is an exploded perspective view of a conventional disc brake device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Disc brake apparatus 11 ... Disc rotor 16 ... Caliper 20, 21 ... Pad 30, 31 ... Friction surface 35 ... Piston 36 ... Caliper tip side inner wall surface 40 ... Cylinder chamber 50 ... First shim 55 ... Second shim 60, 61 ... convex part 70 ... disk brake device 71 ... first shim 72 ... second shim 73, 74 ... convex part

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A 4-64627 (JP, U) JP-A 55-157135 (JP, U) JP-A 5-8065 (JP, U) JP-A 55-157 158336 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16D 65/095 F16D 65/097

Claims (4)

(57) [Claims] 1. A disk rotor having friction surfaces on both sides, a pair of pads provided to face each friction surface of the disk rotor, and a pad straddling the disk rotor and having the pad inside the disk rotor. A caliper having a cylinder chamber to be held and into which brake fluid pressure is introduced; a piston provided in the cylinder chamber of the caliper and moving in the direction of the disk rotor in accordance with the brake fluid pressure; the one pad and the piston And a second shim disposed on the other pad side, wherein the shim is made of a plate material having a spring property. When the brake fluid pressure is low, press the pad first from the side where brake squeal is unlikely to occur, and when the brake fluid pressure is high, it will collapse in the plate thickness direction. Disc brake device being characterized in that an elastic deformable convex portion to allow pressing the pad with substantially the entire shim by. 2. The disk brake device according to claim 1, wherein said convex portion is provided on a trailing side in a rotation direction of the disk rotor. 3. The disk brake device according to claim 1, wherein said convex portion is provided at a position corresponding to a vicinity of an outer peripheral portion of said disk rotor. 4. The disk brake device according to claim 1, wherein said shim is made of a heat-resistant stainless steel plate for a spring, and said projection is provided by cutting and raising a part of said steel plate.