JP2011075036A - Disk brake - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase an effective diameter of a disk rotor with respect to a road wheel size in a caliper floating type disk brake. <P>SOLUTION: A pair of slide pins extended to be positioned on an outer peripheral part of the disk rotor D from a caliper 3 is provided in a position coincident with a straight line L connecting centers of a plurality of cylinders, and respective rotating direction ends of the disk rotor D of a bridge part 20 is adjacent to a part across the disk rotor D of a carrier 2 slidably guiding the slid pin in an inner side of the pair of the slide pins, and thereby, the effective diameter of the disk rotor can be increased with respect to the road wheel size while securing rigidity of the bridge part 20, and the caliper can be smoothly moved. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a disc brake using a hydraulic pressure used as a braking device for an automobile or the like.

  A hydraulic disc brake is generally used as a braking device for an automobile. A general caliper floating type disc brake will be described. The caliper floating type disc brake supports a brake pad disposed on both sides of a disc rotor that rotates with a wheel by a carrier fixed to the vehicle body side, and a cylinder portion equipped with a piston facing one brake pad, A caliper having a claw portion that straddles the disk rotor and faces the opposite brake pad is float-supported by a carrier.

  Then, the piston is advanced by the hydraulic pressure from the master cylinder, one brake pad is pressed against the disk rotor, the caliper is moved by the reaction force, and the other brake pad is pressed against the disk rotor via the claw portion to control it. Generate power. At this time, the brake pad dragged by the disk rotor is supported by the torque receiving surface of the carrier to receive the braking torque.

JP 2008-138752 A

  In the disc brake, the braking force can be increased by increasing the effective diameter of the disc rotor, and the heat capacity can be increased thereby increasing the fade resistance. In order to increase the effective diameter of the disk rotor, it is necessary to increase the size of the road wheel of the vehicle. However, this increases the manufacturing cost, and there is a restriction on increasing the size of the road wheel.

  Therefore, as described in, for example, Patent Document 1, the effective diameter of the disk rotor with respect to the size of the road wheel is devised by devising the shape of the caliper of the disk brake disposed between the disk rotor and the road wheel. Disc brakes have been proposed that make the maximum possible.

  In the caliper floating type disc brake described above, the bridge rotor straddling the caliper disc rotor is thinned to increase the effective diameter of the disc rotor. The bridge portion compensates for the lack of strength due to the reduced thickness by increasing the width of the disk rotor in the rotational direction. In such a caliper having a wide bridge portion, it has been difficult to smoothly move the caliper in the axial direction of the disk rotor with respect to the carrier supporting the caliper.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a disc brake in which the diameter dimension of a disc rotor can be made as large as possible with respect to the load wheel size and the caliper can be moved smoothly.

    In order to solve the above-described problems, the present invention provides a caliper floating type disc brake, wherein a pair of slide pins extending from the caliper so as to be positioned on the outer peripheral portion of the disc rotor connect the centers of a plurality of cylinders. Provided at the same position, each end of the bridge in the rotational direction of the disk rotor straddles the disk rotor of the support member that slidably guides the pair of slide pins inside the pair of slide pins in the rotational direction. It is configured to be located close to the part.

  According to the disc brake according to the present invention, the diameter dimension of the disc rotor can be made as large as possible with respect to the load wheel size, and the caliper can be moved smoothly.

It is a front view of the disc brake concerning one embodiment of the present invention. It is a longitudinal cross-sectional view of the disc brake shown in FIG. FIG. 2 is a top view of the disc brake shown in FIG. 1. FIG. 2 is a side view of the disc brake shown in FIG. 1. It is a rear view of the disc brake shown in FIG. FIG. 2 is a bottom view of the disc brake shown in FIG. 1. It is a graph which shows the relationship between the ratio of the length of a bridge part with respect to the length of the front-end | tip part of the claw part of the caliper of the disc brake shown in FIG. 1, and the rigidity and weight of a caliper. It is a graph which shows the relationship between the aspect-ratio of a brake pad of a disc brake shown in FIG. 1, brake squeal, and braking force.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
As shown in FIGS. 1 to 6, the disc brake 1 according to the present embodiment is a caliper floating disc brake, and includes a disc rotor D (see FIG. 1) that rotates with a wheel and a support that is fixed to the vehicle body side. A carrier 2 as a member, a caliper 3 floatingly supported by the carrier 2, and a pair of brake pads 4 and 5 disposed on both sides of the disk rotor D and supported by the carrier 2 are provided.

  The carrier 2 is disposed on both sides of the disk rotor D, and extends in a substantially straight line along the rotation direction of the disk rotor D, and both ends of the pair of support parts 6 and 7 are connected to the disk rotor. A frame-shaped member that is formed by coupling portions 8 and 9 that are connected to each other across D and has a substantially rectangular opening 10 (see FIG. 6) into which a part of the outer peripheral portion of the disk rotor D is inserted. is there. One support portion 7 disposed on the inner side in the vehicle width direction with respect to the disk rotor D is integrally formed with an attachment portion 11 for fixing the carrier 2 to a vehicle body side member such as a suspension member with a fastener such as a bolt. Has been. Rectangular guide portions 12 and 13 formed at both ends of the brake pads 4 and 5 are engaged with both ends of the support portions 6 and 7 so that the brake pads 4 and 5 extend along the axial direction of the disc rotor D. The rectangular guide grooves 14 and 15 are slidably guided.

  As best shown in FIG. 2, the brake pads 4 and 5 are substantially arc-shaped along the outer periphery of the disk rotor D, and the linings 4A and 5A pressed against the disk rotor D and the back surfaces of the linings 4A and 5A. The back plates 4B and 5B are fixed to each other, and guide portions 12 and 13 are formed at both ends of the back plates 4B and 5B. A pad spring 16 is interposed between the carrier 2 and the brake pads 4 and 5 to facilitate the movement of the brake pads 4 and 5 and protect these sliding portions. Further, return springs 17 are attached to the back plates 4B and 5B to apply a spring force in the direction in which the brake pads 4 and 5 are separated from the disc rotor D.

  The caliper 3 has a main body portion 18 disposed on the inner side in the vehicle width direction with respect to the disk rotor D, a claw portion 19 disposed on the outer side in the vehicle width direction, and a bridge portion that connects these members across the disk rotor D. 20 are integrally formed. Two cylinders 21 are formed in the main body 18 so as to face one brake pad 5, and a piston 22 is slidably inserted into the cylinder 21 via a fallback seal (not shown). . The two cylinders 21 are arranged along the rotational direction of the disc rotor D, and the diameter of the piston 22 is substantially equal to the length X (see FIG. 2) of the radial direction of the disc rotor D of the brake pads 4 and 5. The brake pads 4 and 5 are pressed almost uniformly against the disc rotor D by the two pistons 22. Three or more cylinders 21 may be arranged along the rotation direction of the disk rotor D.

  The bridge portion 20 is formed in an arc shape along the outer peripheral portion of the disc rotor D, and each end portion of the bridge portion 20 in the rotation direction of the disc rotor D is a straight line passing through the centers of the two cylinders 21 of the main body portion 18. A certain gap is provided between the disk rotor D and the disk rotor D. When three or more cylinders 21 are arranged along the rotation direction of the disk rotor D, the straight line L is a straight line passing through the centers of the two cylinders 21 at both ends.

  Further, the bridge portion 20 is set to have a wall thickness t so that a certain gap is formed between the bridge portion 20 and the inner peripheral portion of the road wheel of the vehicle on which the disc brake 1 is mounted. The coupling portions 8 and 9 of the carrier 2 straddling the disc rotor D have substantially the same curvature and thickness as the bridge portion 20 and are formed in an arc shape continuous with the bridge portion 20, so that the disc rotor D and the load wheel So that it does not interfere with.

  The claw portion 19 extends from the bridge portion 20 inward in the radial direction of the disc rotor D to the vicinity of the inner peripheral side end portion of the disc rotor D of the brake pad 4. The claw portion 19 includes a substantially arcuate base portion 19A extending from the bridge portion 20 to a straight line connecting both ends on the inner peripheral side thereof (on the straight line matching the straight line L in the illustrated example), and a straight portion of the base portion 19A. The brake pad 4 has a tip portion 19B extending to the inner peripheral portion of the backing metal 4B along both ends in the rotational direction of the disk rotor D of the lining 4A of the lining 4A. In the example shown in the drawing, both end portions in the rotational direction of the disk rotor D of the tip portion 19B are extended substantially perpendicularly from the straight portion of the base portion 19A. In the claw portion 19, two notches 23 are formed at portions facing the bores of the two cylinders 21, and the tip of the tip 19B has a trifurcated shape. The two notches 23 are used as a tool escape when machining the bores of the two cylinders 21 in the main body 18 of the caliper 3.

  A pair of arm portions 24 are integrally formed at both ends of the main body portion 18 of the caliper 3 so as to extend to the outer peripheral portion side of the disk rotor D and face the coupling portions 8 and 9 of the carrier 2. A pair of slide pins 25 extending parallel to the axis of the disk rotor D are attached to the arm portion 24 by bolts 26 that sandwich the arm portion 24. These slide pins 25 are slidably inserted into the respective pin holes 27 provided in the coupling portions 8 and 9 of the carrier 2 and extend to the outer peripheral portion of the disk rotor D, whereby the caliper 3 is attached to the carrier 2. On the other hand, it is supported by floating so as to be movable along the axial direction of the disk rotor D. As shown in FIG. 2, these slide pins 25 are provided at positions that coincide with a straight line L passing through the centers of the two cylinders 21 in the rotational direction of the disk rotor D. In other words, each slide pin 25 is arranged so that the straight line L is positioned within the range of the diameter d of each slide pin 25. Thereby, the distance of the rotation direction of the disk rotor D of each slide pin 25 can be enlarged as much as possible.

The ends of the bridge rotor 20 in the rotational direction of the disk rotor D are coupled to the connecting portions 8 and 9 of the carrier 2 slidably guiding the slide pins 25 inside the pair of slide pins 25 in the rotational direction. Located close to. The proximity distance between each end of the bridge portion 20 and the coupling portions 8 and 9 of the carrier 2 is set to about 2 mm to 10 mm, more preferably about 3 mm to 6 mm. As a result, as described above, each end portion of the bridge portion 20 can extend to a position on the straight line L passing through the centers of the two cylinders 21 or to a position close thereto, and in the rotational direction of the disk rotor D of the bridge portion 20. The width can be increased as much as possible.
In addition, a bellows-like pin boot 28 is attached to the slide pin 25 in order to protect the sliding portion with the pin hole 27.

  The caliper 3 has a supply port 29 for supplying brake fluid to the two cylinders 21, a bleed plug 30 for releasing air from the cylinder 21, and a bridge portion 20 for inspecting the brake pads 4, 5. A penetrating opening 31 is provided.

Next, the operation of the disc brake 1 will be described.
When brake fluid is supplied from a master cylinder (not shown) to the cylinder 21 via the supply port 29, the piston 22 moves forward while bending the fallback seal, and presses one brake pad 4 against the disc rotor D. The caliper 3 is moved along the slide pin 25 by the reaction force, and the claw portion 19 presses the other brake pad 5 against the disc rotor D to generate a braking force. At this time, the carrier 2 receives the braking torque acting on the brake pads 4 and 5 dragged by the disc rotor D.

  When the hydraulic pressure of the brake fluid from the master cylinder is released, the piston 22 is retracted by a certain amount due to the elasticity of the fallback seal, and both brake pads 4 and 5 are separated from the disc rotor D by the spring force of the return spring 17. Braking is released.

  During this operation, the caliper 3 moves along the pair of slide pins 25. These slide pins 25 are connected to the pin holes 27 provided in the coupling portions 8 and 9 of the carrier 2 as described above. Since the slide pin is slidably inserted into the disk rotor D and extends to the outer periphery of the disk rotor D, the slide length can be made longer than that of the conventional slide pin only on one side of the disk rotor. The whole can be supported stably. For this reason, the caliper 3 can move smoothly in the axial direction of the disc rotor D during braking and release.

  Further, since the pair of slide pins 25 are arranged at positions that coincide with the straight line L passing through the centers of the two cylinders 21 in the rotation direction of the disc rotor D, the piston 22 causes one brake pad 4 to be placed on the disc rotor D. The point of action at which the reaction force generated upon pressing acts on the caliper 3 (mechanically represented by the center position of the cylinder 21) and the axial center of the slide pin 25 substantially coincide with each other in the radial direction of the disc rotor D. become. For this reason, generation | occurrence | production of the moment which arises by the radial shift | offset | difference of an action point and an axial center can be suppressed, and the caliper 3 can move to an axial direction further smoothly.

  In addition, since the pair of slide pins 25 are located outside both ends of the bridge portion 20 of the caliper 3 in the rotation direction of the disc rotor D, the distance between the support positions of the slide pins 25 in the rotation direction of the disc rotor D Thus, even a caliper having a wide bridge portion can be supported in a stable posture, and the caliper 3 can be smoothly moved in the axial direction.

  When the brake pads 4 and 5 are worn, slip occurs between the piston 22 and the fallback seal at the time of braking, and the piston 22 moves forward beyond the amount of bending of the fallback seal and wears the brake pads 4 and 5. By following, the pad clearance is always adjusted to be constant. Even in this case, the sliding length of the slide pin 25 is long, and the caliper 3 can be smoothly moved in the axial direction based on the positional relationship of the slide pin 25 described above.

  Next, since the design elements such as the strength and rigidity of the bridge portion 20 that supports the claw portion 19 across the disc rotor D and the shape of the brake pads 4 and 5 are dragged and affect the occurrence of judder and brake squeal, The shape of each part of the brake pad needs to be determined with sufficient consideration. Therefore, the optimum shape and dimensions of each part of the caliper 3 analyzed using the finite element method (FEM) will be described.

  By reducing the thickness t of the bridge portion 20, the effective diameter of the disk rotor D can be increased with respect to the inner diameter of the load wheel. At this time, if the thickness t of the bridge portion 20 is reduced, the rigidity thereof is reduced. Therefore, the reduction in rigidity can be compensated for by increasing the length W2 of the bridge portion 20 correspondingly. Further, by reducing the thickness t of the bridge portion 20 as much as possible, the effective diameter (diameter dimension) of the disk rotor D can be made as large as possible with respect to the inner diameter of the disk load wheel. Needs to be determined in consideration of various conditions such as the bore diameter of the cylinder 21, the effective area of the linings 4A and 5A of the brake pads 4 and 5 and the castability of the caliper 3 required in an actual vehicle.

  Regarding the rigidity of the caliper 3, when high hydraulic pressure (over 160 MPa) is applied during ABS (anti-lock brake system) operation, the caliper 3 is not permanently deformed, and the brake operation fee is reduced by shortening the stroke of the brake pedal. From the viewpoint of improving the ring, it is desirable that the amount of deformation of the caliper 3 (displacement of the claw portion 19 in the axial direction of the disk rotor D) when a hydraulic pressure of 7 MPa is applied is 0.18 mm or less. It is good that it is about 0.17 mm. By doing in this way, it becomes possible to provide the disc brake which can give a driver a feeling of high rigidity.

  In consideration of the above points, the thickness t1 on the base 19A side of the claw portion 19 of the bridge portion 20 where the largest stress acts in the caliper 3 is set to about 15 mm in the present embodiment, which is preferable. As an example, it is desirable that t1 = about 14 to 16 mm. The length W2 of the bridge portion 20 in the rotation direction of the disk rotor D is preferably such that the ratio W2 / t1 to the thickness t1 is in the range of 12.5 to 15.5. By doing in this way, the effective diameter (diameter dimension) of the disk rotor D can be made comparatively large with respect to the internal diameter of a disk load wheel.

  Further, in the present embodiment, the ratio W2 / W1 of the length W2 of the bridge portion 20 to the length W1 in the rotation direction of the disc rotor D of the tip portion 19B of the claw portion 19 is shown in the left column of FIG. As can be seen from the relationship between the ratio W2 / W1 and the deformation amount of the caliper 3, in order to keep the deformation amount of the caliper 3 to 0.18 mm or less with respect to the hydraulic pressure of 7 MPa, the ratio W2 / W1 is 1.35 or more (W2 / W1 ≧ 1.35). On the other hand, even if the ratio W2 / W1 is larger than 1.55 (W2 / W1> 1.55), the deformation amount of the caliper 3 is hardly reduced. The change in the weight of the caliper 3 at this time is shown in the right column of FIG. As can be seen from FIG. 7, even if the ratio W2 / W1 is made larger than 1.55, the weight of the caliper 3 only increases, and the rigidity of the caliper 3 hardly changes and is not efficient. Therefore, the ratio W2 / W1 of the length W2 of the bridge portion 20 to the length W1 of the tip portion 19B of the claw portion 19 is preferably in the range of 1.35 to 1.55. By setting in this way, it is possible to suppress an increase in weight while suppressing deformation of the caliper 3 during braking, and it is possible to provide a disc brake that is relatively lightweight and can give the driver a high rigidity feeling. It becomes possible.

  On the other hand, the ratio P (hereinafter referred to as “aspect ratio P”) of the length Y in the rotational direction of the disc rotor D to the length X in the radial direction of the disc rotor D of the linings 4A and 5A of the brake pads 4 and 5 As shown in FIG. 8, when the aspect ratio P is large, high-frequency (5 KHz or more) brake squeal is likely to occur, and brake judder is likely to occur due to uneven wear due to drag, and when the aspect ratio P is small, braking force is increased. This causes the problem of lowering. Therefore, it is desirable that the aspect ratio P is about 2.0 to 3.0. By doing so, it is possible to ensure a sufficient braking force while suppressing the occurrence of brake squeal.

  The ratio W2 / X of the length W2 in the rotational direction of the disk rotor D of the bridge portion 20 to the length X in the radial direction of the disk rotor D of the linings 4A and 5A of the brake pads 4 and 5 is 3.5-4. The ratio Y / X of the length Y in the rotational direction to the length X in the radial direction of the disk rotor D of the linings 4A and 5B is in the range of 2.0 to 3.0. Is desirable. By doing in this way, sufficient braking force is securable, suppressing generation | occurrence | production of a brake squeal.

  1 disc brake, 2 carrier (support member), 3 caliper, 4, 5 brake pad, 4A, 5A lining, 18 main body, 19 claw, 19A base, 19B tip, 20 bridge, 21 cylinder, 22 piston, 25 Slide pin, 27 pin hole, D disk rotor

Claims (7)

A pair of brake pads arranged on both sides of the disc rotor;
A support member that supports the pair of brake pads so as to be movable along the axial direction of the disk rotor, and is fixed to the vehicle body side across the disk rotor;
A main body portion in which a plurality of cylinders equipped with a piston that presses one of the pair of brake pads against the disk rotor is disposed along the rotation direction of the disk rotor, and the other of the pair of brake pads is pressed against the disk rotor. A caliper that includes a claw portion that extends in an arc shape along an outer peripheral portion of the disk rotor, and a bridge portion that connects the main body portion and the claw portion across the disk rotor;
A disc brake comprising: a pair of slide pins extending from the caliper so as to be positioned on an outer peripheral portion of the disc rotor, and guiding the caliper with respect to the support member along the axial direction of the disc rotor; In
The pair of slide pins is provided at a position coinciding with a straight line connecting the centers of the plurality of cylinders,
Each end portion of the bridge portion in the rotation direction of the disk rotor straddles the disk rotor of the support member that slidably guides the pair of slide pins inside the pair of slide pins in the rotation direction. Disc brake characterized by being located close to the part. The claw portion has a base portion that extends inward in the radial direction of the disk rotor from the bridge portion, and a tip portion that extends from the base portion along both ends in the rotational direction of the disk rotor of the lining of the brake pad,
The length of the bridge portion in the rotation direction of the disk rotor is such that a ratio of a tip portion of the claw portion to a length in the rotation direction of the disk rotor is 1.35 to 1.55. The disc brake according to 1. The claw portion has a base portion that extends inward in the radial direction of the disk rotor from the bridge portion, and a tip portion that extends from the base portion along both ends in the rotational direction of the disk rotor of the lining of the brake pad,
The length of the bridge portion in the rotation direction of the disk rotor is such that the ratio of the bridge portion to the thickness of the claw portion on the base side is 12.5 to 15.5, and the length of the tip portion of the claw portion is The disc brake according to claim 1, wherein a ratio of the disc rotor to a length in a rotation direction is 1.35 to 1.55. The claw portion has a base portion that extends inward in the radial direction of the disk rotor from the bridge portion, and a tip portion that extends from the base portion along both ends in the rotational direction of the disk rotor of the lining of the brake pad,
The bridge portion extends to a straight line in which both end portions in the rotation direction of the disc rotor pass through the centers of the plurality of cylinders, and the claw portion has a length in the rotation direction of the disc rotor at the tip portion. The disc brake according to claim 1, wherein a ratio of a length of the disc rotor in a rotation direction of the bridge portion to 1.35 to 1.55. The brake pad comprises a lining pressed against the disc rotor and a back plate that supports the lining,
The ratio of the length of the disk rotor in the rotational direction of the bridge portion to the length of the disk rotor in the radial direction of the lining of the brake pad is 3.5 to 4.5, and the disk rotor of the lining The disc brake according to claim 1, wherein the ratio of the length in the rotational direction to the length in the radial direction is 2.0 to 3.0. 5. The brake pad lining according to claim 1, wherein a ratio of a length of the disk rotor in a rotation direction to a length of the disk rotor in a radial direction is 2.0 to 3.0. Disc brake according to any one of the above. The length of the bridge portion in the rotation direction of the disk rotor is set so that the amount of deformation of the caliper is 0.17 to 0.18 mm when a brake fluid pressure of 7 MPa is applied to the cylinder. The disc brake according to any one of claims 1 to 6, wherein the disc brake is provided.

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