JP2009008105A - Disk brake for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a back-up ring suitably energizing a piston seal to a non-braking position direction and surely preventing the bite of the piston seal without causing a trouble in the movement of a piston in a cylinder aperture. <P>SOLUTION: A piston seal installation groove 9 is formed in a circumference direction on the inner circumference surface of the cylinder aperture 6. The piston seal 11 is fitted in the piston seal installation groove 9, and the back-up ring 12 energizing the piston seal 11 in the non-braking position direction is provided between the disk rotor side surface 11b of the piston seal 11 and the disk rotor side surface 9b of the piston seal installation groove 9. The back-up ring 12 comprises a ring body which is elastically deform accompanied by the movement of the piston 7 in the cylinder aperture, has an inner diameter dimension larger than an outer diameter dimension of the piston 7 in a state before the elastic deformation and has an inner diameter dimension the same as the outer diameter dimension of the piston 7 in a state after the elastic deformation. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicle disc brake, and more particularly to a structure of a backup ring that urges a piston seal fitted in a piston seal mounting groove provided on an inner peripheral surface of a cylinder hole in a non-braking position direction.

A vehicular disc brake is configured such that a piston is slidably inserted into a bottomed cylinder hole, and the piston is moved toward the disc rotor by hydraulic fluid supplied into a hydraulic chamber defined between the piston and the bottom of the cylinder hole. The friction pad is pressed against the side surface of the disk rotor by the piston. A piston seal mounting groove is provided around the inner peripheral surface of the cylinder hole, and a piston seal is mounted in the piston seal mounting groove for fluidly supporting the piston in the cylinder hole. In addition, the piston seal is biased toward the non-braking position between the disk rotor side surface of the piston seal and the disk rotor side surface of the piston seal mounting groove, and when the piston seal is subjected to high hydraulic pressure, Is inserted between the cylinder hole and the outer periphery of the piston, so that a so-called bite is prevented and a backup ring for rolling back the piston is mounted (for example, see Patent Document 1).
Shokai 52-135787

  However, since the inner diameter of the backup ring as described above is formed substantially the same as the outer diameter of the piston, when the piston moves in the cylinder hole, the inner peripheral surface of the backup ring slides on the piston. There was a risk of sliding resistance.

  Therefore, the present invention includes a backup ring that urges the piston seal toward the non-braking position without hindering movement of the piston in the cylinder hole and reliably prevents the piston seal from being bitten. The object is to provide a disc brake for a vehicle.

  To achieve the above object, according to the present invention, a piston that pushes a friction pad toward a side surface of a disk rotor is inserted into a cylinder hole formed in a caliper body, and a piston seal is attached to the inner peripheral surface of the cylinder hole. A piston seal is installed in the piston seal mounting groove, and the piston seal is liquid-tightly supported in the cylinder hole, and the piston rotor side surface of the piston seal and the disk rotor side surface of the piston seal mounting groove In the vehicle disc brake provided with a backup ring that biases the piston seal toward the non-braking position between the two, the backup ring is formed of a ring body that is elastically deformed as the piston moves in the cylinder hole. In the state before the elastic deformation, the inner diameter is larger than the outer diameter of the piston, and after the elastic deformation The state is characterized by to roll back the piston by the inner diameter is equal to the outer diameter of the piston. In addition, the backup ring is formed of a conical ring body whose outer periphery is in contact with the outer periphery of the piston seal mounting groove on the disk rotor side and whose inner periphery is in contact with the inner periphery of the disk seal side surface of the piston seal. It is preferable that the inner peripheral side is provided with an elastic bending portion that is curved in an arc shape toward the piston seal side, or the backup ring is provided with an elastic inclined portion that is bent toward the piston seal side on the inner peripheral side. .

  By forming the present invention as described above, when a predetermined hydraulic pressure is applied to the piston during braking, the inner peripheral portion of the piston seal is dragged to the outer peripheral surface of the piston as the piston moves. Even if it is deformed, the backup ring hardly elastically deforms, and since the inner peripheral surface of the backup ring does not slide on the outer peripheral surface of the piston, the backup ring does not hinder the movement of the piston. .

  Further, when a high hydraulic pressure higher than a predetermined hydraulic pressure is applied to the piston, the backup ring is deformed by the piston seal, and the disk rotor side surface of the piston seal, the elastically deformed backup ring, and the piston seal mounting groove The disk rotor side surface is in contact with the disk rotor, and the inner peripheral surface of the backup ring and the outer peripheral surface of the piston are in contact with each other. As a result, the piston seal is not eroded, and the hydraulic pressure is reduced and the backup ring is restored to its original shape. Therefore, the piston seal can be returned to the non-braking position and the piston can be rolled back.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 to 3 show a first embodiment of the present invention, FIG. 1 is an enlarged sectional view of a main part of a vehicle disc brake in a non-braking state, and FIG. 2 is a vehicle disc in which a piston is subjected to high hydraulic pressure. FIG. 3 is a cross-sectional view of a vehicle disc brake.

  The vehicular disc brake 1 includes an action portion 3 a disposed on one side portion of the disc rotor 2, a reaction portion 3 b disposed on the other side portion of the disc rotor 2, and straddles the outside of the disc rotor 2. The caliper body 3 having the bridge portion 3c connected to the vehicle body is fixed to the vehicle body via a slide pin (not shown) and the caliper bracket 4.

  The pair of friction pads 5 arranged opposite to both sides of the disk rotor 2 are formed by a lining 5a that is in sliding contact with the side surface of the disk rotor 2, and a back plate 5b that is held by the caliper body 3, and a bridge portion. The disc rotor 2 is sandwiched between the action portion 3a and the reaction portion 3b on the inner side of 3c so as to be movable in the disc axis direction.

  The action portion 3a of the caliper body 3 is provided with a bottomed cylinder hole 6 opened on the disk rotor 2 side, and a cup-shaped piston 7 is liquid-tight and movable inside the cylinder hole 6. It is inserted. The piston 7 moves in the cylinder hole 6 toward the disk rotor by the hydraulic fluid supplied to the hydraulic chamber 8 defined between the piston 7 and the bottom of the cylinder hole 6, and causes friction on the working part side. The pad 5 is pushed toward the side surface of the disk rotor 2.

  On the inner peripheral surface of the cylinder hole 6, an annular piston seal mounting groove 9 is provided in the middle in the axial direction, and an annular dust seal mounting groove 10 is provided closer to the cylinder hole opening side than the piston seal mounting groove 9. It is installed around. The piston seal mounting groove 9 is formed of a conical surface whose bottom surface 9a is inclined to expand toward the disk rotor side. The piston seal mounting groove 9 is liquid-tight and movable on the outer peripheral surface of the piston 7. A piston seal 11 that is in sliding contact with the disk seal and a backup ring 12 that is disposed on the disk rotor side of the piston seal 11 are fitted, and the dust seal mounting groove 10 is slidably contacted with the outer peripheral surface of the piston 7 to be in a cylinder. A dust seal 13 for preventing dust from entering the hole is fitted.

  The piston seal 11 has a quadrangular cross section, also called a square seal, and when the piston seal 11 is fitted into the piston seal mounting groove 9 formed in the cross-sectional shape as described above, the diameter of the bottom surface 9a is increased. Since the piston seal 11 is slightly smaller than the outer diameter of the piston seal 11 and the bottom surface 9a is a conical surface expanding toward the disk rotor, the piston seal 11 is slightly deformed, and the outer peripheral surface 11a of the piston seal 11 and the piston seal The bottom surface 9a of the mounting groove 9 is in close contact.

  The backup ring 12 has a conical ring body in which the outer peripheral surface 12 a contacts the outer peripheral portion of the disk rotor side surface 9 b of the piston seal mounting groove 9 and the inner peripheral surface 12 b contacts the inner peripheral portion of the disk rotor side surface 11 b of the piston seal 11. The outer diameter dimension is formed to be slightly smaller than the diameter of the bottom surface 9a on the disk rotor side of the piston seal mounting groove 9, and the inner diameter dimension is larger than the outer diameter dimension of the piston 7 before elastic deformation. Is also formed to have the same outer diameter as the piston 7 in a state after elastic deformation.

  When hydraulic fluid that has been boosted into the hydraulic chamber 8 of the caliper body 3 is supplied by the driver's braking operation, the piston 7 moves forward in the cylinder hole 6 toward the disc rotor, and the friction pad 5 on the acting portion 3a side is moved to the disc. Pushing in the direction of the rotor 2, the lining 5 a of the friction pad 5 is pressed against one side of the disk rotor 2. Next, due to this reaction, the caliper body 3 moves in the direction of the action part 3a by the guide of the slide pin, the reaction force claw 3d of the reaction part 3b pushes the friction pad 5 on the reaction part 3b side, and the friction pad 5 is pressed against the other side of the disk rotor 2. As a result, a braking force acts on the disk rotor 2.

  As shown in FIG. 1, the piston seal 11 before braking is located on the side opposite to the disk rotor of the piston seal mounting groove 9, the disk rotor side surface 9 b of the piston seal mounting groove 9, and the disk rotor side surface 11 b of the piston seal 11. The backup ring 12 is disposed in a gap formed between the two. The backup ring 12 has an outer peripheral portion disposed at a corner where the disk rotor side surface 9b and the bottom surface 9a of the piston seal mounting groove 9 intersect, and an inner peripheral portion abuts against an inner peripheral side of the disk rotor side surface 11b of the piston seal 11, The inner peripheral surface 12b of the backup ring 12 and the outer peripheral surface 7a of the piston 7 are not in contact with each other.

  From this state, the inner peripheral surface 11c of the piston seal 11 is dragged to the outer peripheral surface 7a of the piston 7 by the advance of the piston 7 during braking, and the backup ring 12 is slightly elastically deformed by the piston seal 11. When the pressure in the hydraulic chamber 8 decreases due to the release of the braking operation, the piston 7 rolls back by a predetermined amount due to the restoring force of the backup ring 12 returning to its original shape. Thus, when the piston 7 moves through the cylinder hole 6 with a predetermined hydraulic pressure, the backup ring 12 hardly undergoes elastic deformation, so the inner peripheral surface 12b of the backup ring 12 is the outer peripheral surface of the piston 7. There is no sliding contact with 7a, and the backup ring 12 does not hinder the movement of the piston 7.

  Further, when a high hydraulic pressure higher than a predetermined hydraulic pressure is applied to the piston 7, the backup ring 12 is deformed by the piston seal 11 as shown in FIG. 2, and the disk rotor side surface 11 b of the piston seal 11, The elastically deformed backup ring 12 and the disk rotor side surface 9b of the piston seal mounting groove 9 are in contact with each other, and the inner peripheral surface 12b of the backup ring 12 and the outer peripheral surface 7a of the piston 7 are in contact with each other. There is no possibility that the inner peripheral portion of the cylinder will be eaten between the cylinder hole 6 and the outer peripheral surface 7 a of the piston 7. Further, since the hydraulic pressure in the hydraulic chamber 8 decreases and the backup ring 12 returns to the original shape, the piston seal 11 can be returned to the non-braking position and the piston 7 can be rolled back by a predetermined amount. Further, since the backup ring 12 is inclined toward the return side of the piston 7, the piston seal 11 can be satisfactorily returned to the non-braking position.

  FIG. 4 is an enlarged cross-sectional view of a main part of a non-braking vehicle disc brake showing a second embodiment of the present invention, and FIG. 5 is a main part of a non-braking vehicle disc brake showing a third embodiment of the present invention. In the enlarged cross-sectional view, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the second embodiment shown in FIG. 4, the backup ring 21 includes an elastic bending portion 21 a that is curved in an arc shape toward the piston seal 11 on the inner peripheral side. The outer diameter of the backup ring 21 is formed to be slightly smaller than the diameter of the bottom surface 9a on the disk rotor side of the piston seal mounting groove 9, and the inner diameter (the diameter of the tip of the elastic bending portion) is elastic bending. The outer diameter of the piston 7 is larger than that of the piston 7 before the portion 21a is deformed, and the outer diameter of the piston 7 is the same as that of the elastic curved portion 21a after the deformation.

  In the third embodiment shown in FIG. 5, the backup ring 22 includes an elastic inclined portion 22 a that bends in a square shape toward the piston seal 11 on the inner peripheral side. The outer diameter dimension of the backup ring 12 is formed to be slightly smaller than the diameter of the bottom surface 9a on the disk rotor side of the piston seal mounting groove 9, and the inner diameter dimension (the diameter of the tip of the elastic inclined portion) is the elastic inclination. The outer diameter of the piston 7 is larger than that of the piston 7 before the portion 22a is deformed, and the outer diameter of the piston 7 is the same as that of the piston 7 after the deformation of the elastic inclined portion 22a.

  The present invention is not limited to the above-described embodiment, and the shape of the piston seal mounting groove and the piston seal is arbitrary, and is not limited to the pin slide type disc brake, but may be applied to a piston facing type disc brake. it can.

It is a principal part expanded sectional view of the disc brake for vehicles of the non-braking state showing the example of the 1st form of the present invention. FIG. 3 is an enlarged cross-sectional view of the main part of the vehicle disc brake in a state where the piston is also subjected to high hydraulic pressure. It is a sectional view of a disk brake for vehicles similarly. It is a principal part expanded sectional view of the disc brake for vehicles of the non-braking state which shows the 2nd example of the present invention. It is a principal part expanded sectional view of the disc brake for vehicles of the non-braking state which shows the 3rd example of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Vehicle disc brake, 2 ... Disc rotor, 3 ... Caliper body, 3a ... Action part, 3b ... Reaction part, 3c ... Bridge part, 3d ... Reaction force claw, 4 ... Caliper bracket, 5 ... Friction pad, 5a ... Lining, 5b ... back plate, 6 ... cylinder hole, 7 ... piston, 7a ... outer peripheral surface, 8 ... hydraulic chamber, 9 ... piston mounting groove, 9a ... bottom surface, 9b ... disk rotor side surface, 10 ... dust seal mounting groove, 11 ... Piston seal, 11a ... outer peripheral surface, 11b ... disc rotor side surface, 11c ... inner peripheral surface, 12 ... backup ring, 12a ... outer peripheral surface, 12b ... inner peripheral surface, 13 ... dust seal

Claims (4)

A piston that pushes the friction pad toward the side surface of the disk rotor is inserted into a cylinder hole formed in the caliper body, and a piston seal mounting groove is provided around the inner peripheral surface of the cylinder hole. A piston seal that liquid-tightly supports the piston in the cylinder hole is fitted to the piston seal, and the piston seal is placed in a non-braking position between the disk rotor side surface of the piston seal and the disk rotor side surface of the piston seal mounting groove. In the vehicle disc brake provided with a backup ring that biases in the direction, the backup ring is formed of a ring body that is elastically deformed as the piston moves in the cylinder hole, and has an inner diameter in a state before elastic deformation. The dimension is larger than the outer diameter of the piston, and the inner diameter is outside the piston in the state after elastic deformation. Vehicle disc brake, characterized in that the piston is rolled back by the same as the dimension. The backup ring is formed of a conical ring body whose outer periphery is in contact with the outer periphery of the piston seal mounting groove on the disk rotor side and whose inner periphery is in contact with the inner periphery of the side surface of the disk rotor of the piston seal. The disc brake for vehicles according to claim 1. The vehicular disc brake according to claim 1, wherein the backup ring includes an elastic bending portion that is curved in an arc shape toward the piston seal side on an inner peripheral side. 2. The vehicle disc brake according to claim 1, wherein the backup ring includes an elastic inclined portion that bends toward the piston seal side on an inner peripheral side.

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