JP4844900B2 - Disc brake - Google Patents

Description

  The present invention relates to a disc brake used for braking a vehicle such as an automobile.

  In a disc brake mounted on an automobile or the like, a cylinder equipped with a piston that is supported by a carrier fixed to the vehicle body on both sides of a disc rotor that rotates with a wheel and that is opposed to one brake pad. There is a caliper floating type disc brake in which a caliper having a claw portion straddling the disc rotor and facing the opposite brake pad is supported in a floating manner by a carrier.

  The caliper floating type disc brake pushes one brake pad directly against the disc rotor by the advance of the piston, moves the caliper by the reaction force, and pushes the other brake pad against the disc rotor via the claw part to apply the braking force. Is generated. At this time, the brake pad dragged by the disk rotor is brought into contact with the torque receiving surface of the carrier to receive the braking torque.

  By the way, in such a caliper floating type disc brake, if the return amount of the brake pad is insufficient when the brake is released, dragging occurs, the fuel consumption is deteriorated due to an increase in running resistance, and the brake pad is unevenly worn. Cause the problem of causing brake judder. In addition, there is a problem that when the brake pad is dragged by the disc rotor and collides against the torque receiving surface of the carrier at the start of braking, a collision sound (so-called cron sound) is generated.

Therefore, conventionally, as described in Patent Document 1, for example, a return spring is attached to the brake pad, and the brake pad is pulled away from the disk rotor by the spring force, and the brake pad is always attached to the torque receiving surface of the carrier. By pressing, it is possible to prevent the brake pad from returning insufficiently and from generating a clunk sound.
JP 2002-327780 A

  However, the caliper floating disc brake provided with the conventional return spring has the following problems. As the brake pad wears, the pad clearance is automatically adjusted by the fallback function of the piston seal, etc., and the brake pad moves forward to the disc rotor side. (Spring force) increases. As a result, the return amount of the brake pad is increased, the pad clearance is increased beyond a specified value, and the response of the disc brake at the time of braking may be lowered.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a disc brake including a return spring that can maintain an appropriate return amount of the brake pad even when the brake pad is worn. And

  In order to solve the above problems, the present invention provides a pair of brake pads that are disposed on both sides of a disk rotor and pressed against the disk rotor by a piston, and the pair of brake pads are connected to the shaft of the disk rotor. A support member that is movably supported along the direction and fixed to the vehicle body side, a base end portion is attached to the brake pad, and a distal end portion presses the support member side to release the brake pad from the disc rotor. In the disc brake provided with a return spring that urges in a separating direction, an inclined portion that inclines in a direction separating from the brake pad along the circumferential direction of the disc rotor as the distance from the disc rotor increases on the support member side. The tip of the return spring is pressed against the inclined portion.

  According to the disc brake of the present invention, when the brake pad is worn, the tip of the return spring slides on the inclined portion to follow the wear, thereby suppressing an excessive increase in the spring force of the return spring. An appropriate amount of brake pad return can be maintained.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
A first embodiment of the present invention will be described with reference to FIGS. As shown in FIGS. 1 and 2, the disc brake 1 of the present embodiment is a caliper floating disc brake, which is a disc rotor D that rotates together with wheels, and a carrier 2 that is a support member fixed to the vehicle body side. , A caliper 3 floatingly supported by the carrier 2 and a pair of brake pads 4 (only one side is shown) disposed on both sides of the disk rotor D and supported by the carrier 2.

  The carrier 2 straddles the disc rotor D and supports the pair of brake pads 4 by support portions 6 and 7 arranged on both sides thereof, and is generally arranged inside the disc rotor D of the vehicle body. The mounting portion 8 formed on the one support portion 6 is fixed to a member on the vehicle body side such as a knuckle with a bolt or the like. In the support portions 6 and 7, inward torque receiving surfaces 6A, 6B and 7A, 7B are formed at both ends in the rotational direction of the disk rotor D indicated by arrows in the drawing, respectively. Rectangular guide grooves 6C, 6D and 7C, 7D extending along the axial direction of the disk rotor D are formed in 6B and 7A, 7B (one guide groove 6C, 6D is not shown in the figure). .

  The pair of brake pads 4 includes a friction material 4A pressed against the disk rotor D and a back plate 4B that is firmly fixed to and supports the friction material 4A, and rectangular ears are provided at both ends of the back plate 4B. Portions 4C and 4D are projected. In the pair of brake pads 4, the back plate 4B is inserted between the inward torque receiving surfaces 6A, 6B and 7A, 7B of the carrier 2, and the ears 4C and 4D are guide grooves 6C, 6D (not shown) and 7C and 7D are fitted and supported by the carrier 2 so as to be slidable along the axial direction of the disk rotor D.

  A pad spring 9 attached to the carrier 2 side is provided between one torque receiving surface 6A, 7A and the guide grooves 6C, 7C of the carrier 2 and one end of the back plate 4B of the pair of brake pads 4 and the ear 4C. Between the other torque receiving surfaces 6B and 7B and the guide grooves 6D and 7D and the other end of the back plate 4B and the ears 4D and 5D. The pad springs 9 and 10 facilitate the movement of the pair of brake pads 4 and protect the carrier 2. Further, shims 11 for preventing brake noise are attached to the back surfaces of the back plates 4B of the pair of brake pads 4, respectively.

  The caliper 3 is provided with a cylinder portion 13 equipped with two pistons (not shown) facing the brake pad 4 disposed on the inner side of the disc rotor D of the vehicle body, and straddles the disc rotor D. A claw portion 14 that faces the other brake pad 4 is formed. In the caliper 3, slide pins 17 and 18 are respectively attached to arm portions 15 and 16 formed at both ends of the caliper 3, and these slide pins 17 and 18 are provided in guide holes (not shown) provided at both ends of the carrier 2. ) Is slidably inserted, and is floatingly supported so as to be movable along the axial direction of the disk rotor D. In the figure, reference numerals 19 and 20 denote pin boots for protecting the slide pins 17 and 18, reference numeral 21 denotes a supply port for supplying brake fluid to the cylinder portion 13, and reference numeral 22 denotes air venting in the cylinder portion 13. The bleed plug is shown.

  The cylinder portion 13 and the piston are sealed by a fallback seal (not shown). When brake fluid is supplied from the supply port 21 to the cylinder portion 13, the fallback usually occurs as the piston advances. When the seal is bent by a certain amount and then the hydraulic pressure of the brake fluid is released, the piston moves backward by the amount of the deflection due to the elasticity of the fallback seal. When the brake pad 4 wears and the forward movement amount of the piston exceeds a certain amount, slip occurs between the piston and the fallback seal, and the piston follows the wear of the brake pad 4, so that the brake pad 4 wears. Adjust the pad clearance to a certain level.

  Return springs 23 are attached to the back plates 4B of the pair of brake pads 4, respectively. The return spring 23 will be described in detail with reference to FIGS. 3 and 4. The return spring 23 is disposed at the end of the back plate 4B on the disk rotor turn-in side, that is, at the rear end in the rotational direction of the disk rotor D indicated by an arrow in FIGS. The return spring 23 is fixed to the back plate 4B by caulking a pin boss 24 protruding in the vicinity of the base portion of the ear portion 4C of the back plate 4B, and in a direction away from the disc rotor D substantially perpendicularly from the back plate B. It has an extending upright portion 23A, and an inclined portion 23B that is bent from the upright portion 23A toward the distal end side of the ear portion 4C and inclined in a direction approaching the disk rotor D. The tip portion 23C of the inclined portion 23B is curled away from the disk rotor D and is in contact with the inclined portion 25 provided on the carrier 2 side. The inclined portion 23B of the return spring 23 is inclined by an angle θ (see FIG. 3) with respect to a plane parallel to the surface of the disk rotor D.

  The inclined portion 25 is provided on the carrier 2 side so as to face the distal end portion 23 </ b> C of the return spring 23, and the base end side of the inclined portion 25 with respect to the axis parallel to the axial direction of the disk rotor D is the return spring 23. It approaches the upright portion 23A, and the tip side is inclined in a direction away from the upright portion 23A. In other words, the inclined portion 25 is inclined in the disk rotor circumferential direction from the brake pad 4 as the distance from the disk rotor D increases.

  When the brake pad 4 supported by the carrier 2 moves to the disk rotor D side and the tip 23C of the return spring 23 is pressed against the inclined portion 25, the return spring 23 is bent and the reaction force is inclined. The inclination of the portion 25 acts as a reaction force against the component force F <b> 1 (see FIG. 4) in the direction toward the disk rotor D in a direction in which the brake pad 4 is separated from the disk rotor D and is parallel to the surface of the disk rotor D. As a reaction force against the small component force F2 (see FIG. 4), the back plate 4B of the brake pad 4 acts in the direction of always pressing the torque receiving surfaces 6B and 7B on the opposite side. Further, as the brake pad 4 wears and the back plate 4B moves to the disk rotor D side, the distal end portion 23C of the return spring 23 slides on the inclined portion 25 to the disk rotor D side.

  5 and 6, the pad spring 9 is substantially U-shaped so as to cover the torque receiving surfaces 6A and 7A and the guide grooves 6C and 6D of the carrier 2 arranged on both sides of the disk rotor D. (See FIG. 5). In the present embodiment, the inclined portion 25 is formed integrally with the pad spring 9 and extends from the portion of the pad spring 9 on the bottom of the guide grooves 6C and 6D to both sides. The carrier 2 is formed with an inclined surface 26 that is inclined in the same manner as the inclined portion 25. When the pad spring 9 is attached to the carrier 2, the back surface of the inclined portion 25 is in contact with the inclined surface 26. It has become.

  The inclined portion 25 is formed with a corrugated surface 25A having irregularities in the sliding direction of the distal end portion 23C of the return spring 23. When the distal end portion 23C slides on the corrugated surface 25A, a resistance that increases or decreases due to the irregularities is formed. It comes to grant.

Next, the operation of the present embodiment configured as described above will be described.
When brake fluid is supplied from the master cylinder (not shown) to the cylinder portion 13 via the supply port 21, the piston advances and presses one brake pad 4 against the disc rotor D while bending the return spring 23, The caliper 3 is moved by the reaction force, and the claw portion 14 presses the other brake pad 4 against the disc rotor D while bending the return spring 23 to generate a braking force. At this time, the brake pad 4 dragged by the disc rotor D presses the pad spring 10, and the braking torque is received by the torque receiving surfaces 6 </ b> B and 7 </ b> B of the carrier 2.

  When the hydraulic pressure of the brake fluid from the master cylinder is released, the piston moves backward by a certain amount due to the elasticity of the fallback seal, and due to the spring force of the return spring 23 (reaction force of the component force F1 in the axial direction of the disc rotor D), Both brake pads 4 are separated from the disc rotor D and braking is released. In this way, both the brake pads 4 can be separated from the disc rotor D by the spring force of the return spring 23. Therefore, the brake drag is suppressed, and the brake caused by the deterioration of fuel consumption and the uneven wear of the brake pad 4 is suppressed. Generation of judder can be suppressed.

  Further, the brake pad 4 is applied to the torque receiving surfaces 6B and 7B on the disk rotor delivery side, that is, the front side in the rotational direction of the disk rotor D by the spring force of the return spring 23 (reaction force of the component force F2 parallel to the surface of the disk rotor D). Since the pressure is constantly pressed, it is possible to suppress the generation of a crank sound when the brake pad 4 is dragged to the disk rotor D and collides with the torque receiving surfaces 6B and 7B at the start of braking.

  When the brake pad 4 is worn, a slip occurs between the piston and the fallback seal during braking, and the piston advances beyond the deflection amount of the fallback seal to follow the wear of the brake pad 4, thereby Always keep the clearance constant. At this time, as the brake pad 4 moves to the disc rotor D side, the tip 23C of the return spring 23 slides on the inclined portion 25 to the disc rotor D side according to the amount of wear of the brake pad 4, The amount of bending of the return spring 23 during braking is maintained within a certain range. Thereby, it is possible to prevent the return amount of the brake pad 4 from excessively increasing and the pad clearance from exceeding a specified value, and it is possible to prevent a decrease in the response of the disc brake during braking.

  A tip that slides on the inclined portion 25 following the wear of the brake pad 4 by forming a wavy surface 25A on the inclined portion 25 and imparting an appropriate resistance to the sliding of the tip portion 23C of the return spring 23. The position of the portion 23C can be stabilized, and the spring force of the return spring 23 can be stably maintained within a certain range. Then, the reaction force of the component force F2 parallel to the surface of the disk rotor D can be sufficiently generated by the spring force of the return spring 23, and the brake pad 4 is constantly pressed stably against the torque receiving surfaces 6B and 7B. be able to.

  In the above embodiment, the spring force of the return spring 23 depends on the reaction force (return load) against the axial component force F1 of the disk rotor D and the surface of the disk rotor D according to various conditions such as the mass of the brake pad 4. Although it is necessary to appropriately determine the reaction force (side push load) with respect to the parallel component force F2, these can be adjusted to some extent by the angle θ of the inclined portion 23B of the return spring 23. FIG. 7 shows a recommended value of the angle θ (spring angle) of the inclined portion that provides an appropriate return load and side load with respect to the mass of the brake pad 4 (pad mass), and the return load and side pushing load at that time. .

  In the above embodiment, the inclined portion 25 is formed integrally with the pad spring 9. However, the inclined surface 26 formed on the carrier 2 is used as the inclined portion, and the front end portion 23 </ b> C of the return spring 23 is directly brought into contact therewith. You may do it. In this case, the wavy surface 25 </ b> A is formed on the inclined surface 26. Further, the inclined surface 26 formed on the carrier 2 may not be formed, but only the inclined portion 25 formed integrally with the pad spring 9 may be formed. In this case, no extra meat is added to the carrier 2. Therefore, it is possible to reduce the weight and facilitate die cutting during casting.

  In the above embodiment, the return spring 23 and the inclined portion 25 are arranged on the disk rotor turn-in side, and the brake pad 4 is applied to the torque receiving surfaces 6B and 7B on the disk rotor turn-out side by the component force of the spring force of the return spring 23. When the pressing is always performed, the return spring 23 and the inclined portion 25 may be arranged on the disk rotor outlet side, and both the disk rotor inlet side and the outlet side may be provided. You may arrange in.

The feature points in this embodiment are listed as follows.
The inclined portion 25 is formed integrally with a pad spring 9 interposed between the carrier 2 (support member) and the brake pad 4. Thereby, compared with the case where an inclined part is provided in the carrier 2, the smooth process of the inclined part of the carrier 2 can be omitted, and manufacture of a disc brake becomes easy. Further, when the inclined portion 25 is formed only by the pad spring 9, it is possible to reduce the weight because it is not necessary to add extra thickness to the carrier 2, and it is easy to remove the die at the time of casting. Can do.

  The inclined portion 25 has a wavy surface 25A. As a result, an appropriate resistance can be given to the sliding of the tip 23C of the return spring 23, and the position of the tip 23C sliding on the inclined portion 25 following the wear of the brake pad 4 can be stabilized. The spring force of the return spring 23 can be stably maintained within a certain range.

  The return spring 23 and the inclined portion 25 are disposed on the side of the disk rotor D that is turned in, and the brake pad 4 is always pressed against the side of the disk rotor D that is the carrier 2 (support member) by the spring force of the return spring 23. It is characterized by doing. Thereby, at the start of braking, it is possible to suppress the generation of a crumb sound when the brake pad 4 is dragged by the disk rotor D and collides with the torque receiving surfaces 6B and 7B.

1 is a plan view showing a disc brake according to an embodiment of the present invention with a part broken away. FIG. 2 is a side view of the disc brake shown in FIG. 1. It is a top view which expands and shows the return spring and the inclination contact part which are the principal parts of the disc brake shown in FIG. It is a figure which expands further and shows the return spring and inclination contact part shown in FIG. It is a front view of the pad spring in which the inclination contact part of the disc brake shown in FIG. 1 was formed integrally. FIG. 6 is a side view of the pad spring shown in FIG. 5. 2 is a chart showing angles of inclined portions of a return spring for obtaining an appropriate spring force with respect to the mass of a brake pad in the disc brake shown in FIG.

Explanation of symbols

  1 disc brake, 2 carrier (support member), 4 brake pad, 23 return spring, 25 inclined portion, D disc rotor

Claims (1)

A pair of brake pads disposed on both sides of the disk rotor and pressed against the disk rotor by a piston, and the pair of brake pads are movably supported along the axial direction of the disk rotor, A support member to be fixed; a base end portion attached to the brake pad; and a return spring that presses the support member side to urge the brake pad away from the disk rotor. In the disc brake,
The support member side is provided with an inclined portion that is inclined in a direction away from the brake pad along the circumferential direction of the disk rotor as the distance from the disk rotor increases.
The disc brake according to claim 1, wherein a tip portion of the return spring presses the inclined portion.

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