JP2013108516A - Brake pad - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brake pad that can enhance strength at a portion pressed by a piston while weight thereof is reduced.SOLUTION: A brake pad includes: a friction material of which one face side abuts a disc rotor at braking; and a rear plate 41 disposed at the other face side of the friction material and pressed by a piston 21 of a caliper. At the rear plate 41, a plurality of metal rings 49 are buried along a pressing area A of the piston 21 in a resin part 48 mainly made of heat-curable resin. The metal rings 49 are arranged such that an axial direction thereof coincides with a thick direction of the rear plate 41.

Description

  The present invention relates to a brake pad.

  There is a brake pad in which a back plate of a brake pad is formed of a material mainly composed of a synthetic resin and a metal plate is embedded in order to increase the strength of a portion pressed by a piston (see, for example, Patent Document 1).

Japanese Utility Model Publication No. 62-181727

  In the above brake pad, the back plate is formed of a material mainly composed of a synthetic resin to reduce the weight. However, since the metal plate is embedded, the effect of reducing the weight is reduced.

  Accordingly, an object of the present invention is to provide a brake pad that can increase the strength of a portion pressed by a piston while reducing the weight.

  In order to achieve the above object, the present invention is such that the back plate has a resin portion mainly composed of a thermosetting resin, and a plurality of metal rings are embedded along the pressing area of the piston. It arrange | positions so that the axial direction may correspond with the thickness direction of the said backplate.

  According to the present invention, it is possible to increase the strength of the portion pressed by the piston while reducing the weight.

It is sectional drawing which shows the disc brake in which the brake pad which concerns on one Embodiment of this invention is used. It is a front view showing a brake pad concerning one embodiment of the present invention. It is a rear view which shows the brake pad which concerns on one Embodiment of this invention. It is sectional drawing which shows the brake pad which concerns on one Embodiment of this invention.

  A brake pad according to an embodiment of the present invention will be described below with reference to the drawings.

  FIG. 1 shows a disc brake 11 in which a brake pad 10 according to this embodiment is used. The disc brake 11 is for braking a vehicle such as an automobile, and includes a carrier 12, two brake pads 10 and 13, and a caliper 14.

  The carrier 12 is disposed so as to straddle the outer diameter side of the disk rotor 15 that rotates together with a wheel (not shown) to be braked, and is fixed to a non-rotating portion of the vehicle. The two brake pads 10 and 13 are supported by the carrier 12 so as to be slidable in the axial direction of the disk rotor 15 in a state of being opposed to both surfaces of the disk rotor 15. The caliper 14 is supported by the carrier 12 so as to be slidable in the axial direction of the disc rotor 15 while straddling the outer diameter side of the disc rotor 15, and presses the brake pads 10 and 13 against the disc rotor 15. Friction resistance is applied to the disk rotor 15. In the following description, the radial direction of the disk rotor 15 is referred to as a disk radial direction, the axial direction of the disk rotor 15 is referred to as a disk axial direction, and the rotational direction of the disk rotor 15 is referred to as a disk rotational direction.

  The caliper 14 has a caliper body 20 that is supported by the carrier 12 across the disk rotor 15, and a piston 21 that is held in the caliper body 20 and arranged to face one surface of the disk rotor 15. doing.

  The caliper body 20 includes a cylinder portion 25, a bridge portion 26, and a claw portion 27, and is configured integrally.

  The cylinder portion 25 has a bottomed cylindrical shape in which a bore 30 is formed along the disk axial direction so as to open to the disk rotor 15 side, and is disposed opposite to one surface side of the disk rotor 15. The piston 21 is slidably inserted into the bore 30. The bridge portion 26 is formed to extend in the axial direction of the disk rotor 15 outside the cylinder portion 25 in order to straddle the disk rotor 15. The claw portion 27 extends inward in the disk radial direction from the opposite side of the bridge portion 26 to the cylinder portion 25 and faces the other surface side of the disk rotor 15.

  A pipe connection hole 31 connected to a brake pipe (not shown) is formed at the bottom of the cylinder part 25. The caliper 14 advances the piston 21 toward the disk rotor 15 by the hydraulic pressure introduced into the bore 30 via the brake pipe, and presses the inner brake pad 10 with the piston 21 to contact the disk rotor 15. Let Further, the caliper 14 slides in the direction in which the cylinder portion 25 is separated from the disk rotor 15 with respect to the carrier 12 by the pressing reaction force of the piston 21, and the outer side brake pad 13 is pressed by the claw portion 27 to press the disc rotor. 15 is contacted. In this way, the brake pads 10 and 13 on both sides are sandwiched between the piston 21 and the claw portion 27 and pressed against the disk rotor 15 to generate a frictional resistance, thereby generating a braking force.

  A piston seal 33 that seals the gap with the piston 21 is held at an intermediate position in the axial direction of the bore 30, and a circle between the piston 21 and the piston 30 is located closest to the opening in the axial direction of the bore 30. An annular boot 34 is interposed.

  The piston 21 has a cylindrical portion 36 and a bottom portion 37 that closes one end side of the cylindrical portion 36 in the axial direction. The piston 21 is slidably inserted into the bore 30 of the cylinder portion 25 on the outer peripheral surface thereof with the opening side opposite to the bottom portion 37 of the cylindrical portion 36 facing the claw portion 27. An end surface 38 on the opening side of the cylindrical portion 36 is along the direction orthogonal to the axis of the piston 21 and forms an annular shape with a constant radial width.

  The brake pad 10 has a friction material 40 whose one surface abuts against the disk rotor 15 during braking, and is slidably supported on the carrier 12 and pressed by the piston 21 of the caliper 14. It consists of a back plate 41.

  The brake pad 13 also has a friction material 42 that contacts one side of the disk rotor 15 during braking, and a claw portion of the caliper body 20 of the caliper 14 that is provided on the other surface side of the friction material 42 and is slidably supported by the carrier 12. 27 and a back plate 43 pressed by 27.

  Hereinafter, the brake pad 10 according to the present embodiment will be further described.

  The friction material 40 of the brake pad 10 is composed of a phenol resin, which is a thermosetting resin, as a binder. The friction material 40 is a predetermined mixing ratio of a compounding material for friction material composed of phenol resin, copper fiber, potassium titanate fiber, rock wool, aramid fiber, NBR powder, cashew dust, graphite, zircon powder, barium sulfate and the like. It is formed by mixing and heating compression molding. In the friction material 40, an abutting surface 45 that abuts on the disk rotor 15 and an affixing surface 46 that is affixed to the back plate 41 are formed in parallel. The friction material 40 is attached to the back plate 41 with an adhesive such as epoxy-phenol resin.

  As shown in FIG. 2, the back plate 41 is formed to be slightly larger than the friction material 40 and holds the friction material 40. The back plate 41 is supported by the carrier 12 at both ends in the longitudinal direction in such a posture that its longitudinal direction is along the disk rotation direction and its height direction is along the disk radial direction. As shown in FIG. 3, the back plate 41 is formed by embedding a plurality of metal rings 49 made of steel in a resin portion 48 formed of a uniform material mainly composed of a phenol resin that is a thermosetting resin. Is.

  As shown in FIG. 4, the resin portion 48 has a flat surface portion 50 that holds the friction material 40 and a flat back surface portion 51 on the opposite side of the friction material 40, and thus has a constant thickness. It has become. The resin portion 48 is formed by mixing a back plate compounding material composed of a phenol resin, glass fiber, and other inorganic fillers at a predetermined mixing ratio, followed by heat compression molding.

  The metal ring 49 has a hollow structure including a cylindrical portion 53 and an annular flange portion 54 that protrudes radially outward from one axial end portion of the cylindrical portion 53. The end surface 55 opposite to the flange portion 54 of the metal ring 49 is formed only by the cylindrical portion 53, and the end surface 56 on the flange portion 54 side of the metal ring 49 is formed by the cylindrical portion 53 and the flange portion 54. ing. Both end faces 55 and 56 of the metal ring 49 are along the direction perpendicular to the axis of the metal ring 49. Therefore, the metal ring 49 has a constant axial length, and the cylindrical portion 53 also has a constant axial length. The flange portion 54 also has a constant axial length.

  The metal ring 49 is embedded in the resin portion 48 such that the end surface 55 opposite to the flange portion 54 is flush with the front surface portion 50 and the end surface 56 on the flange portion 54 side is flush with the back surface portion 51. In the back plate 41, the end surface 55 of the flush metal ring 49 and the surface portion 50 of the resin portion 48 constitute a flat friction material holding surface 57 that holds the friction material 40. The end surface 56 and the back surface portion 51 of the resin portion 48 constitute a flat piston facing surface 58 that faces the piston 21. The friction material holding surface 57 and the piston facing surface 58 are also parallel.

  As described above, all the metal rings 49 are arranged so that their axial directions coincide with the thickness direction that is the direction connecting the friction material holding surface 57 and the piston facing surface 58 of the back plate 41. Further, the flange portion 54 of the metal ring 49 faces the piston facing surface 58 of the back plate 41, and the end of the metal ring 49 opposite to the flange portion 54 faces the friction material holding surface 57 of the back plate 41. Is arranged in.

  The plurality of metal rings 49 are intermittently arranged along the pressing area A indicated by hatching in FIG. 3 of the piston 21. The pressing area A is a portion that overlaps the brake pad 10 in the projection surface obtained by projecting an end surface 38 that is a pressing surface for pressing the brake pad 10 of the piston 21 in the axial direction of the piston 21. The pressing area A is composed of two arcuate areas Aa and Ab that are symmetrical with respect to the length direction of the brake pad 10 (disk rotation direction). Then, a plurality of metal rings 49 are provided evenly in each of the arcuate regions Aa and Ab, specifically, two in total, and a total of four are provided. The plurality of metal rings 49 are each formed in a size that fits within the range of the arcuate regions Aa and Ab.

  The number of metal rings 49 is not limited to four as long as it is plural, but it is preferable to provide the same number in each of the arcuate regions Aa and Ab.

  The back plate 41 is a mold in which a plurality of metal rings 49 are set at predetermined positions, and is formed by heat-compression molding a back plate compounding material and molding a resin portion 48. At that time, the metal ring 49 is brought into close contact with the resin portion 48 and integrated. At this time, a mold is formed so that the resin portion 48 does not enter the inside of the metal ring 49. Then, the back plate 41 and the preform of the friction material 40 coated with the adhesive are put into a mold, and the preform 40 is heated and compression molded to form the friction material 40 and affix it to the back plate 41. As a result, the brake pad 10 is obtained. At that time, a part of the preformed product enters the metal ring 49 of the back plate 41. That is, the friction material 40 integrally has a protrusion 61 that protrudes from the sticking surface 46 and enters the inside of the metal ring 49. In other words, the friction material 40 enters the metal ring 49. The protrusion 61 is formed for all the metal rings 49.

  In addition, after the resin part 48 is heat compression-molded by a mold without the metal ring 49, a hole is formed in the resin part 48 by machining, and the metal ring 49 may be fitted and bonded to the hole.

  According to this embodiment described above, the back plate 41 is formed by embedding a plurality of metal rings 49 along the pressing area A of the piston 21 in the resin portion 48 mainly composed of a thermosetting resin. The strength of the portion pressed by the piston 21 of the back plate 41 by the plurality of metal rings 49 can be increased. And since the some metal ring 49 is arrange | positioned intermittently along the press area | region A of the piston 21, weight reduction can be achieved.

  Further, since the metal ring 49 is arranged so that its axial direction coincides with the thickness direction of the back plate 41, it is possible to suppress the bending that occurs in the back plate 41 due to the pressing force of the piston 21. . Therefore, the influence which the deformation | transformation of the backplate 41 has on the friction material 40 can be reduced.

  Further, since the friction material 40 enters the inside of the metal ring 49, it is possible to suppress the friction material 40 from falling off the back plate 41.

  Further, a flange portion 54 is formed at the end of the metal ring 49, and the flange portion 54 is disposed facing the piston facing surface 58 of the back plate 41, so that the pressing force of the piston 21 is applied by the flange portion 54. As a result, the strength of the portion pressed by the piston 21 of the back plate 41 can be effectively increased.

  A mold with a plurality of metal rings 49 made of steel set at a predetermined position is charged with a compounding material for a back plate made of phenol resin, glass fiber and other inorganic fillers, and the mold temperature is 180 ° C. and molding is performed. The resin portion 48 was molded by heat compression molding at a pressure of 40 MPa and a molding time of 10 minutes. Thereafter, the molded product was taken out of the mold and heat treated by holding at 180 ° C. to 220 ° C. for 360 minutes to obtain a back plate 41. A plurality of metal rings 49 are arranged on the back plate 41 along the pressing area A of the piston 21 as described above. An epoxy-phenol resin adhesive was applied to the friction material holding surface 57 of the back plate 41 and dried at 80 ° C. for 30 minutes.

  On the other hand, various friction material compounding materials consisting of phenol resin, copper fiber, potassium titanate fiber, rock wool, aramid fiber, NBR powder, cashew dust, graphite, zircon powder and barium sulfate are weighed, Mixing was performed using a Redige mixer to obtain a mixed powder. The amount of the mixed powder required for each friction material 40 was measured, put into a preforming mold, and pressure molded at room temperature to prepare a preformed product. The back plate 41 and the preform formed by drying and applying the adhesive as described above are put into a mold heated to 150 ° C., subjected to heat compression molding with a molding pressure of 40 MPa and a molding time of 4 minutes, and then subjected to 220 in a thermostatic bath. The temperature was raised to 0 ° C. and left to cool, and heat treatment was performed for a total of 8 hours. Thereby, the brake pad 10 was obtained.

  The finished brake pad 10 is subjected to a torque breaking strength test at a inertia of 70 kgf · m using a caliper having a piston area of 25 cm 2, which is a general condition for ordinary passenger cars, using a brake dynamo test device. The test was carried out in accordance with “Device Strength Dynamometer Test Method”.

  In the torque breaking strength test, the maximum deceleration generated in a passenger car is gradually increased from a torque equivalent to 7.8 m / s2 at a torque interval equivalent to 1.95 m / s2, and each decrease from 80 ° C. and 50 km / h. This is a test in which braking is performed five times at each speed, and a test for evaluating whether there is an abnormality in the brake pad 10 with a torque equivalent to a deceleration of 23.5 m / s2 multiplied by a safety factor of 3 times.

  As a result of the test, in the example, no abnormality occurred in the brake pad 10 even at the torque corresponding to the deceleration of 23.5 m / s2.

DESCRIPTION OF SYMBOLS 10 Brake pad 14 Caliper 15 Disc rotor 21 Piston 40 Friction material 41 Back plate 48 Resin part 49 Metal ring 54 Flange part 58 Piston opposing surface A Pressing area

Claims (3)

In a brake pad comprising: a friction material whose one side is in contact with the disk rotor during braking; and a back plate provided on the other side of the friction material and pressed by a caliper piston;
The back plate is formed by embedding a plurality of metal rings along a pressing region of the piston in a resin portion mainly composed of a thermosetting resin, and the metal ring has an axial direction that is a thickness of the back plate. A brake pad characterized by being arranged to coincide with the direction.   The brake pad according to claim 1, wherein the friction material enters the metal ring.   The brake pad according to claim 1 or 2, wherein a flange portion is formed at an end portion of the metal ring, and the flange portion is disposed facing a piston facing surface of the back plate.

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