JP4495367B2 - Vehicle disc brake - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a disc brake used in a traveling vehicle such as an automobile or a motorcycle, and more particularly to a structure for preventing dragging of a friction pad during non-braking or braking release.
[0002]
[Prior art]
An example of a vehicle disc brake that prevents dragging of the friction pad is disclosed in Japanese Utility Model Publication No. 59-72330.
[0003]
In this technique, a pawl piece of a pad hold spring fixed to a back plate of a friction pad is elastically engaged with an inner peripheral wall of a piston inserted into a cylinder hole of a caliper body. It has a base attached to the back plate and three claw pieces extending from the base to the inside of the piston, and two of the three claw pieces are on a radial line intersecting the piston center. And place the other one on another radial line perpendicular to this radial line, and set the claw pieces to different lengths, and engage the engaging part on the tip side with the opening of the piston. By combining them, the friction pad is forcibly pulled back from the side surface of the disk rotor in association with the piston that retreats the cylinder hole toward the bottom by releasing the braking operation.
[0004]
[Problems to be solved by the invention]
However, in the above-described prior art, since the three claw pieces of the pad hold spring are arranged at unequal intervals, the pullback force of the piston acts on the friction pad unevenly and tilts the friction pad. There is a risk that the friction pad lining may be dragged to the disk rotor to cause partial wear.
[0005]
Further, since the engaging portion on the tip side of each claw piece is formed so as to press the inner peripheral wall of the piston toward the outer peripheral side, it is difficult to assemble each claw piece to the piston, which takes time. Furthermore, when the base portion of the pad hold spring is attached to the back plate, the pad hold spring may turn around the base portion.
[0006]
Therefore, the present invention provides a vehicle disc brake equipped with a pad hold spring that can be pulled back from the side surface of the disc rotor without tilting the friction pad when braking is released, and that has a simple structure and excellent assembly. It is intended to provide.
[0007]
[Means for Solving the Problems]
Order to achieve the above object, comprises a friction pad disposed opposite to the opposite sides of the de Isukurota, and a bottomed cylindrical piston that presses at least one of said friction pad on a side surface of the disc rotor, said friction A pad hold spring is attached to the back plate of the pad, a pawl piece of the pad hold spring protruding in the direction opposite to the disk rotor is engaged with the inner peripheral wall of the piston, and the friction pad is attached to the side surface of the disk rotor as the piston moves backward. a vehicle disc brake to pull back from the first invention, the pad hold spring is provided from the center of the base portion which is fixed to the front SL back plate radially at equal intervals least three or more said pawls, The front end side of the claw piece is bent into a “<” shape to form an engagement portion with the piston, and an engagement recess is formed on the inner peripheral wall of the piston. The provided, the engaging portions while engaged wear engaging recess, is characterized in that is curved in an arc shape the top outer surface of the engaging portion in the width direction of the claw piece.
[0008]
In the second invention, a regular polygonal mounting hole having the same number of corners as the claw pieces is formed in the base of the pad hold spring, and the corners are directed toward the tip of the claw pieces. The mounting hole is provided. Further, according to a third invention, in the first invention, a regular polygonal attachment hole having the same number of corners as the claw pieces is opened at the base of the pad hold spring, and the corners are arranged in the direction of the tip of the claw pieces. The mounting hole is arranged toward the head. According to a fourth aspect of the present invention, in the first to third aspects of the invention, a spring mounting portion having the same cross-sectional shape as the mounting hole is projected from the back plate, and the mounting hole is inserted into the spring mounting portion. The pad hold spring is attached to the back plate by caulking the tip of the attachment portion.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, each embodiment of the present invention will be described in more detail with reference to the drawings.
FIGS. 1 to 4 show a first embodiment of the present invention. A caliper body 2 used in a disc brake 1 has both sides of a disc rotor 3 that rotates integrally with a wheel in the direction of arrow A. And an action part 2a and a reaction part 2b that are arranged opposite to each other, and a bridge part 2c that connects them across the outside of the disk rotor 3.
[0010]
The action portion 2a is provided with a bottomed cylindrical cylinder hole 4 opened to the disk rotor 3 side, and a bottomed cylindrical piston 5 is provided in the cylinder hole 4 so that the opening 5a faces the disk rotor 3 side. It is supported by the square seal 6 so as to be liquid-tight and movable, and an engagement groove 5c (an engagement recess of the present invention) for connecting a pad hold spring 15 described later to the inner peripheral wall 5b of the piston 5 Is installed around. A hydraulic pressure chamber 7 is defined between the bottom of the cylinder hole 4 and the bottom of the piston 5, and hydraulic fluid boosted by a hydraulic master cylinder (not shown) is supplied to the hydraulic pressure chamber 7. Yes.
[0011]
The reaction portion 2b is integrally formed with a reaction force claw 2d, and mounting arms 2e, 2e are provided along one side surface of the disc rotor 3 on the disk insertion side and the extraction side of the action portion 2a. The sliding pins 9 and 9 project from the mounting disk 2 and 2e on the tip disk rotor side using mounting bolts 10 and 10, respectively.
[0012]
A caliper bracket 11 is fixed to a vehicle body (not shown) on one side of the disc rotor 3 where the action portion 2a is disposed. The caliper bracket 11 has an outer side of the disc rotor 3 parallel to the disc axis. A pair of caliper support arms 11a, 11a are provided extending across the bridge portion 2c so as to straddle.
[0013]
Each of the caliper support arms 11a is provided with a bottomed insertion hole 11b that is open to the action part 2a side, and the caliper body 2 described above has the above-described sliding pins 9 protruding from the action part 2a side. 9 is inserted into the insertion holes 11b and 11b and supported so as to be movable in the disk axial direction. The caliper support arms 11a and 11a are provided with four pad guide portions 11c opposite to each other with the disc rotor 3 interposed therebetween, and a pair of friction pads 12 and 12 are supported by the pad guide portions 11c.
[0014]
Each friction pad 12 includes a lining 12 a that is in sliding contact with the disk rotor 3, and a back plate 12 b that is held by the caliper bracket 11. Ear pieces 12c and 12c protrude from both sides of the back plate 12b, and the friction pad 12 has a pad guide between the ear piece 12c and 12c between the disk rotor 3 and the action part 2a or reaction part 2b. By being hooked on the portions 11c and 11c, like the caliper body 2, it is suspended so as to be movable in the disk axial direction. The friction pad 12 on the side of the action part 2a is provided with a spring mounting part 12d having an equilateral triangular section in the middle of the back surface of the back plate 12b. A pad hold spring 15 is attached to the spring mounting part 12d. ing.
[0015]
The pad hold spring 15 is formed by bending a thin metal plate, and has a central base portion 15a and three claws protruding radially at equal intervals from the outer peripheral edge of the base portion 15a to one side. It consists of a piece 15b. The base portion 15a is provided with equilateral triangular mounting holes 15c that are the same as the spring mounting portions 12d of the back plate 12b, with the respective corner portions 15d aligned with the axis B of the claw piece 15b. 15d is directed toward the tip of the claw piece 15b, and the three sides of the attachment hole 15c are disposed between the three claw pieces 15b, thereby ensuring the radial width of the base portion 15a. The necessary and sufficient rigidity is ensured.
[0016]
The front end side of the claw piece 15b is an engagement portion 15e that bends in a “<” shape toward the central axis of the base portion 15a, and the top outer surface 15f of the engagement portion 15e is connected to the piston 5. While forming in the circular arc surface of the same diameter as the engaging groove 5c bottom part, the front end side is formed in the taper shape. The top outer surface 15f mainly improves convenience when the claw piece 15b is inserted into the piston 5, and does not necessarily have the same curvature as the bottom of the engagement groove 5c. Further, the tip end side is tapered from the top outer surface 15f, so that the insertion into the piston 5 is further facilitated.
[0017]
The pad hold spring 15 configured as described above inserts the spring mounting portion 12d of the back plate 12b through the mounting hole 15c of the base portion 15a while directing the claw piece 15b to the side opposite to the back plate 12b. It is fixed to the back plate 12b by caulking the tip of 12d. The three claw pieces 15b are in a free state before being inserted into the piston 5, and the top outer surfaces 15f, 15f, 15f are located outside the inner peripheral wall of the piston 5, and each claw piece 15b has a reduced diameter. Then, the piston 5 and the friction pad 12 on the action portion 2a side are interposed via the pad hold spring 15 by inserting the engagement portion 15e into the engagement groove 5c elastically by inserting the piston 5 into the piston 5. Connected.
[0018]
The present embodiment is configured as described above. When the hydraulic fluid boosted by the hydraulic master cylinder is supplied to the hydraulic chamber 7, the piston 5 elastically deforms the square seal 6 and the cylinder hole 4. , The piston 5 pushes the friction pad 12 on the acting portion 2 a side toward the disk rotor 3, and the lining 12 a of the friction pad 12 is pressed against one side of the disk rotor 3.
[0019]
Next, due to this reaction, the caliper body 2 moves in the direction of the action part 2a by the guide of the sliding pins 9, 9, and the reaction force claw 2d pushes the friction pad 12 on the reaction part 2b side toward the disk rotor 3, The lining 12a of the friction pad 12 is pressed against the other side of the disk rotor 3 to perform a braking action.
[0020]
Further, when the above-described braking operation is released, the piston 5 retreats the cylinder hole 4 toward the bottom by the restoring force of the square seal 6, and accordingly, the action portion 2 a that is continuous via the piston 5 and the pad hold spring 15. The side friction pad 12 is forcibly pulled back from one side of the disk rotor 3.
[0021]
Since the pad hold spring 15 has the engagement portions 15e of the three claw pieces 15b engaged with the engagement grooves 5c on the inner periphery of the piston 5 at equal intervals in the circumferential direction, the traction force from the piston 5 is reduced. It acts evenly on the friction pad 12 on the acting portion 2a side through the pad hold spring 15, and can be stably pulled back from the side surface of the disk rotor 3 without tilting the friction pad 12 when the brake is released. As a result, the lining 12a is not dragged by the disk rotor 3 and does not cause uneven wear or drag sound. Pulling back the friction pad 12 using the pad hold spring 15 is also beneficial when the vehicle is running without performing a braking operation.
[0022]
Furthermore, since the top outer surface 15f of the engaging portion 15e of the claw piece 15b is formed in an arc shape having the same diameter as the bottom of the engaging groove 5c of the piston 5, each claw piece 15d is connected to the opening 5a of the piston 5 from the opening 5a. The engaging groove 5c can be smoothly pushed into the engaging groove 5c in a short time, so that the assembling property is improved, and when the engaging groove 5c is engaged, the engaged state can be maintained well.
[0023]
Further, since the pad hold spring 15 is attached by caulking the equilateral triangular spring attaching portion 12d formed in the back plate 12 through the attaching hole 15c formed in the equilateral triangle, it is possible to reliably prevent rotation. In addition, the mounting hole 15c has three corners positioned on the axis B of the claw piece 15b, and the three sides of the mounting hole 15c are arranged between the three claw pieces 15b, whereby the base 15a In addition, it is possible to secure a necessary and sufficient rigidity in the base portion 15a while securing the width in the radial direction and forming the entire pad hold spring 15 with a small amount of material.
[0024]
FIG. 6 shows a second embodiment of the present invention. In the first embodiment described above, the spring mounting portion 12e at the center of the back surface of the back plate 12b has a regular quadrangular prism shape, and this spring mounting portion 12e is used. The shape is different from the shape of the pad hold spring 20 that is caulked and fixed to the back plate 12b.
[0025]
The pad hold spring 20 is composed of a central base portion 20a and four claw pieces 20b protruding radially at equal intervals from the outer peripheral edge of the base portion 20a toward one side. The base 20a is provided with a square mounting hole 20c, which is the same as the spring mounting portion 12e, with the corner 20d positioned on the axis C of the claw piece 20b. The front end side of the claw piece 20b is an engaging portion 20e that bends in a “<” shape toward the central axis of the base portion 20a. The top outer surface 20f of the engaging portion 20e While forming in the circular arc surface of the same diameter as the engaging groove 5c bottom part, the front-end | tip is tapering.
[0026]
In this embodiment, the number of the claw pieces 20b is increased from that in the first embodiment, and the four engaging portions 20e are engaged with the engaging grooves 5c of the piston 5 at intervals of 90 degrees. The friction pad 12 acts more evenly on the acting portion 2a side, further prevents the friction pad 12 from tilting when the brake is released, and can be reliably and easily pulled back from one side of the disk rotor 3. Become.
[0027]
The present invention can be applied not only to the pin slide type disc brake shown in the above-described embodiment but also to other types of disc brakes. Further, the number of pawl pieces of the pad hold spring may be three or more, and can be appropriately selected according to the size of the piston and the friction pad. Further, in each of the above-described embodiments, a circumferential engagement groove is provided on the inner peripheral wall of the piston, and the pawl piece of the pad hold spring is engaged with this engagement groove. Not limited to this, depending on the number of the claw pieces, an engagement concave portion may be provided on the inner peripheral wall of the piston, and the claw pieces may be engaged with the engagement concave portions, respectively.
[0028]
【The invention's effect】
As described above, according to the vehicle disc brake of the present invention, with a simple structure, the friction pad at the time of releasing the brake can be reliably pulled back from the side surface of the disc rotor, and the lining is unevenly worn. No dragging noise is generated. Furthermore, it is excellent in assemblability and does not require time and effort for assembly with the piston. Further, the pad hold spring attached to the back plate of the friction pad can be reliably prevented from rotating. In addition, it is possible to ensure the necessary and sufficient rigidity at the base portion while forming the entire pad hold spring with a small amount of material.
[Brief description of the drawings]
FIG. 1 is a cross-sectional plan view of a disc brake showing a first embodiment of the present invention. FIG. 2 is a cross-sectional side view of a disc brake showing a first embodiment of the present invention. FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG. 3. FIG. 5 is a cross-sectional view taken along the main portion of the disk brake showing the second embodiment of the present invention.
DESCRIPTION OF SYMBOLS 1 ... Disc brake, 2 ... Caliper body, 3 ... Disc rotor, 4 ... Cylinder hole, 5 ... Piston, 5a ... Opening part, 5b ... Inner peripheral wall, 5c ... Engaging groove, 7 ... Hydraulic chamber, 11 ... Caliper bracket , 12 ... friction pad, 12a ... lining, 12 ... back plate, 12d, 12e ... spring mounting portion, 15, 20 ... pad hold spring, 15a, 20a ... base, 15b, 20b ... claw piece, 15c, 20c ... mounting hole , 15e, 20e ... engaging portion

Claims (4)

A friction pad disposed opposite to both sides of the disk rotor, and a bottomed cylindrical piston that presses at least one of the friction pads against a side surface of the disk rotor, and a pad hold spring is provided on a back plate of the friction pad. For a vehicle in which the front end of a claw piece of a pad hold spring that protrudes in the direction opposite to the disc rotor is engaged with the inner peripheral wall of the piston, and the friction pad is pulled back from the side of the disc rotor as the piston moves backward in disc brakes, the pads hold spring is pre SL provided from the center of the base portion which is fixed to the back plate radially at equal intervals least three or more said pawls, shaped "V" the tip side of the claw piece Bent into an engagement portion with the piston, and an engagement recess is provided on the inner peripheral wall of the piston, and the engagement portion is formed in the engagement recess. While engaged wear, vehicle disc brake, characterized in that is curved in an arc shape the top outer surface of the engaging portion in the width direction of the claw piece. A friction pad disposed opposite to both sides of the disk rotor, and a bottomed cylindrical piston that presses at least one of the friction pads against a side surface of the disk rotor, and a pad hold spring is provided on a back plate of the friction pad. For a vehicle in which the front end of a claw piece of a pad hold spring that protrudes in the direction opposite to the disc rotor is engaged with the inner peripheral wall of the piston, and the friction pad is pulled back from the side of the disc rotor as the piston moves backward In the disc brake, the pad hold spring is provided with at least three claw pieces radially from the central base fixed to the back plate at equal intervals, and the same number of claw pieces as the claw pieces at the base of the pad hold spring. A regular polygonal mounting hole having a corner is opened, and the corner is directed toward the tip of the claw piece. Ri attached car dual disc brake it, characterized in that the hole is disposed. A regular polygonal attachment hole having the same number of corners as the claw pieces is opened at the base of the pad hold spring, and the attachment holes are arranged with the corners directed toward the tip of the claw pieces. claim 1 Symbol mounting disc brake for vehicles, wherein.   A spring mounting portion having the same cross section as the mounting hole is protruded from the back plate, the mounting hole is inserted into the spring mounting portion, and the tip of the spring mounting portion is crimped to attach the pad hold spring to the back plate. The disc brake for vehicles according to any one of claims 1 to 3, which is attached.

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