JP6966273B2 - Vehicle disc brakes - Google Patents

Description

The present invention relates to a vehicle disc brake, and more particularly to a vehicle disc brake provided with a piston seal that rolls back a piston when braking is released.

Conventionally, in a disc brake for a vehicle, a piston seal groove is provided around the inside of a cylinder hole formed in a caliper body, and a piston seal that rolls back the piston when braking is released is fitted in the piston seal groove. In some cases, the piston is inserted into the cylinder hole via the above, but the piston seal groove formed inside the cylinder hole is difficult to process, and it is troublesome to fit the piston seal into this piston seal groove. It was hanging. For this reason, there is a case in which a piston seal groove is provided around the piston and the piston seal is fitted in the piston seal groove to improve workability and work efficiency (see, for example, Patent Document 1). ..

Japanese Unexamined Patent Publication No. 2016-142316

However, as in Patent Document 1 described above, when the piston seal is attached to the piston, it is difficult for the piston seal to exert a tense force on the cylinder hole, so that it is difficult to reliably roll back the piston when braking is released.

Therefore, an object of the present invention is to provide a vehicle disc brake capable of reliably rolling back a piston with a piston seal when braking is released, while improving workability and work efficiency.

In order to achieve the above object, the vehicle disc brake of the present invention is a vehicle disc brake in which a piston for pushing a friction pad toward the side surface of the disc rotor is inserted in a cylinder hole formed in a caliper body. An oil seal groove is provided on the outer peripheral surface of the piston on the bottom side of the cylinder hole, and an oil seal for sealing brake oil is fitted in the oil seal groove. A piston seal groove having an outer peripheral wall is provided around the piston seal groove, and a piston seal having a rollback portion for rolling back the piston when braking is released is fitted in the piston seal groove, and the piston in the rollback portion is rolled back. The piston return force to be caused is set to be larger than the sliding resistance of the oil seal with the cylinder hole, and the piston seal groove is recessed toward the bottom side of the cylinder hole on the outer peripheral side of the side wall of the bottom of the cylinder hole. A groove is provided around the piston seal, and a protrusion to be inserted into the concave groove is formed on the side surface of the bottom of the cylinder hole. It is characterized in that it comes into contact with the concave groove when loaded.

Further, the piston seal is provided with a dust seal portion formed on the inner peripheral portion on the cylinder hole opening side of the rollback portion so that the inner peripheral surface gradually projects toward the inner peripheral side toward the cylinder hole opening side surface. Is preferable. Further, it is preferable to provide a peripheral groove between the rollback portion and the dust seal portion.

Further, the piston seal may be provided with a non-contact portion that does not come into contact with the outer peripheral wall of the groove on the outer peripheral portion on the cylinder hole opening side. Further, it is preferable that the piston seal is provided with a notch on the inner peripheral surface of the rollback portion. Further, it is preferable that the piston seal has a metal annular member molded in the rollback portion.

Furthermore, before Symbol caliper body is preferably formed by die casting.

According to the vehicle disc brake of the present invention, a piston seal groove is formed on the opening side of the cylinder hole and an oil seal groove is formed on the piston, and the piston seal groove and the oil seal groove are provided in a place where processing is easy. , Piston seal groove and oil seal groove can be easily machined. In addition, a piston seal groove and an oil seal groove are provided in a place where the piston seal and the oil seal can be easily assembled, so that the piston seal and the oil seal can be easily fitted and the cost can be reduced. .. Furthermore, by setting the piston return force of the rollback part of the piston seal to be larger than the sliding resistance of the oil seal with the cylinder hole, the piston can be rolled back satisfactorily without being affected by the oil seal when braking is released. Can be made to.

Further, by forming a dust seal portion formed by gradually projecting the inner peripheral surface toward the side surface of the cylinder hole opening toward the inner peripheral side on the inner peripheral portion on the cylinder hole opening side of the rollback portion of the piston seal, the piston is formed. A dust seal function that prevents dust from entering the cylinder hole can be added to the piston seal that has a rollback function to return the piston, and an increase in the number of parts can be prevented. Further, by providing the peripheral groove between the rollback portion and the dust seal portion, it becomes easy for the rollback portion and the dust seal portion to act independently.

In addition, by providing a non-contact portion that does not contact the groove outer peripheral wall on the outer peripheral portion of the piston seal on the cylinder hole opening side, the tension on the cylinder hole opening side of the piston seal is reduced and the piston slides satisfactorily during braking. Can be made to. Further, when the dust seal portion is provided on the cylinder hole opening side of the piston seal, the tension of the dust seal portion can be reduced, and the piston can be satisfactorily rolled by the action of the rollback portion without being affected by the dust seal portion. You can make it back.

Further, by providing the notch on the inner peripheral surface of the rollback portion of the piston seal, air is released from the notch when assembling the piston seal, and the assembling property of the piston seal can be improved. .. Further, by molding a metal annular member into the rollback portion of the piston seal, the shearing force and the tense force of the rollback portion can be increased, and the piston can be satisfactorily rolled back when the braking is released.

Further, a concave groove that becomes concave toward the bottom side of the cylinder hole is provided around the outer peripheral side of the side wall of the bottom of the cylinder hole of the piston seal groove, and a protrusion to be inserted into the concave groove is provided on the side surface of the bottom of the cylinder hole of the piston seal. The protrusion is not in contact with the concave groove when the hydraulic pressure is not loaded, and abuts on the concave groove when the hydraulic pressure is applied, so that the piston seal can be satisfactorily assembled into the piston seal groove and the hydraulic pressure is formed. When a load is applied, the protrusion comes into contact with the concave groove to increase the shearing force of the piston seal, and the piston can be satisfactorily rolled back when the braking is released.

Further, since the caliper body is formed by the die casting method, the finishing process of the caliper body can be simplified and the cost can be further reduced.

It is sectional drawing of the disc brake for a vehicle which shows the 1st Embodiment example of this invention. Similarly, it is a cross-sectional view of a main part of a disc brake for a vehicle when no hydraulic pressure is applied. Similarly, it is a cross-sectional view of a main part of a disc brake for a vehicle under a hydraulic pressure load. It is also a front view of the piston seal. It is also a rear view of the piston seal. FIG. 6 is a sectional view taken along line VI-VI of FIG. It is a partially cutaway perspective view of the piston seal which shows the 1st Embodiment example of this invention. It is sectional drawing of the main part of the disc brake for a vehicle at the time of no hydraulic load which shows the 2nd Embodiment of this invention. Similarly, it is a cross-sectional view of a main part of a disc brake for a vehicle under a hydraulic pressure load. It is sectional drawing of the piston seal which shows the 3rd Embodiment example of this invention.

1 to 7 are views showing an example of a first embodiment of a vehicle disc brake of the present invention. The vehicle disc brake 1 of the present embodiment includes an action portion 3a arranged on one side of the disc rotor 2, a reaction portion 3b arranged on the other side of the disc rotor 2, and these being the disc rotor 2. A caliper body 3 having a bridge portion 3c that straddles the outside and is connected is fixed to a caliper bracket (not shown) attached to a vehicle body via a slide pin (not shown).

The pair of friction pads 4 and 4 arranged to face each other on both side surfaces of the disc rotor 2 are formed of a lining 4a that is in sliding contact with the side surface of the disc rotor 2 and a back plate 4b that is held by the caliper body 3. A disc rotor 2 is sandwiched between the action portion 3a and the reaction portion 3b inside the bridge portion 3c so as to be movable in the disc axial direction.

The caliper body 3 is formed by a die casting method, and the working portion 3a is provided with a bottomed cylinder hole 3d having an opening on the disc rotor side, and a cup-shaped piston 5 is provided in the cylinder hole. It is liquid-tight and movably interpolated with the opening side facing the disc rotor side. The piston 5 moves in the cylinder hole 3d toward the disc rotor by the brake oil supplied to the hydraulic chamber 6 defined between the piston 5 and the bottom of the cylinder hole 3d, and is a friction pad on the acting portion side. 4 is pushed toward one side surface of the disc rotor 2. Further, the reaction portion 3b is provided with a reaction force claw 3e that pushes the friction pad 4 on the reaction portion side toward the other side surface of the disc rotor 2.

A piston seal groove 3f is provided around the opening side of the cylinder hole 3d, and a piston seal 7 that rolls back the piston 5 when braking is released is fitted in the piston seal groove 3f. Further, an oil seal groove 5a is provided around the outer peripheral surface of the piston 5 on the bottom side of the cylinder hole, and an oil seal 8 for sealing brake oil is fitted in the oil seal groove 5a.

The piston seal groove 3f has a cylinder hole bottom side wall 3g orthogonal to the cylinder shaft CL and a groove outer peripheral wall 3h parallel to the cylinder shaft CL, and the cylinder hole bottom side is on the inner peripheral side of the cylinder hole bottom side wall 3g. A notch 3i gradually inclined toward the piston side is formed.

The piston seal 7 has a substantially square cross section, which is also called a square seal, and is formed on the inner peripheral portion on the cylinder hole opening side by gradually projecting the inner peripheral surface toward the cylinder hole opening side surface 7f toward the inner peripheral side. The dust seal portion 7a is provided, and a rollback portion 7c is formed on the inner peripheral surface on the bottom side of the cylinder hole with respect to the dust seal portion 7a via a peripheral groove 7b. Further, the rollback portion 7c is provided with three notches 7e at equal intervals in the circumferential direction over the peripheral groove 7b and the cylinder hole bottom side surface 7d, and further, the outer peripheral portion of the cylinder hole opening side surface 7f. Is inclined toward the bottom of the cylinder hole toward the outer peripheral surface, and a non-contact portion 7g that does not come into contact with the groove outer peripheral wall 3h is formed.

The oil seal groove 5a connects the cylinder hole bottom side wall 5b and the cylinder hole opening side wall 5c orthogonal to the cylinder shaft CL, and the cylinder hole bottom side wall 5b and the cylinder hole opening side wall 5c, and is inside the groove parallel to the cylinder shaft CL. It has a peripheral wall 5d, and the oil seal 8 is formed by an O-ring. Further, the piston return force that the rollback portion 7c of the piston seal 7 rolls back the piston 5 is set to be larger than the sliding resistance generated when the oil seal 8 is in sliding contact with the cylinder hole 3d. It is set according to the material and shape of the piston seal 7 and the oil seal 8.

In the vehicle disc brake 1 formed as described above, as shown in FIG. 2, the oil seal 8 is fitted in the oil seal groove 5a of the piston 5, and the piston seal 7 is fitted in the piston seal groove 3f of the cylinder hole 3d. The piston 5 is inserted into the cylinder hole 3d in a state where the piston 5 is fitted. The piston seal 7 is fitted into the piston seal groove 3f in a state where the outer peripheral portion of the cylinder hole bottom side surface 7d is in contact with the cylinder hole bottom side wall 3g, and the inner peripheral side of the cylinder hole bottom side surface 7d and the cylinder hole bottom side wall 3g. A slight gap E1 is formed between the two, and the inner peripheral surface of the dust seal portion 7a and the inner peripheral surface of the rollback portion 7c are in close contact with the outer peripheral surface of the piston 5. Further, the oil seal 8 is in close contact with the inner peripheral surface of the cylinder hole 3d.

In the vehicle disc brake 1 thus formed, when the brake oil boosted by the driver's braking operation is supplied to the hydraulic chamber 6 of the caliper body 3, the piston 5 moves through the cylinder hole in the direction of the cylinder hole opening. The friction pad 4 on the acting portion side is pushed forward, and the lining 4a of the friction pad 4 is pressed against one side surface of the disc rotor 2. Next, due to this reaction, the caliper body 3 moves in the direction of the acting portion 3a by the guidance of the slide pin, presses the friction pad 4 on the reaction portion side against the other side surface of the disc rotor 2, and a braking force acts. As shown in FIG. 3, when the piston 5 moves toward the opening of the cylinder hole, the dust seal portion 7a is in sliding contact with the outer peripheral surface of the piston 5, and the rollback portion 7c is the piston together with the piston 5. Transforms in the direction of movement. Further, the oil seal 8 slides in close contact with the inner peripheral surface of the cylinder hole 3d to seal the brake oil in the hydraulic chamber 6.

When the braking is released and the pressure in the hydraulic chamber 6 drops, the piston 5 rolls back a predetermined amount due to the restoring force that returns the piston seal 7 to its original shape, and the caliper body 3 slides toward the reaction part to the original position. , And both friction pads 4 and 4 are separated from the disc rotor 2. At this time, as the piston 5 retracts, the tip of the dust seal portion 7a slides into contact with the outer peripheral surface of the piston 5, so that the dust adhering to the tip side of the piston 5 is efficiently removed, and the dust into the cylinder hole is collected. Prevent intrusion.

In this embodiment, as described above, the piston seal groove 3f is formed on the opening side of the cylinder hole 3d, and the oil seal groove 5a is formed on the piston 5, so that the piston seal groove 3f and the oil seal groove 5a are located in easy-to-process locations. And can be provided to improve workability. Further, the piston seal 7 is easily fitted because the piston seal groove 3f is provided in the opening of the cylinder hole 3d, and the oil seal 8 is also fitted because the oil seal groove 5a is provided in the piston 5. Since it is easy to put on, work efficiency can be improved.

Further, since the piston return force of the rollback portion 7c of the piston seal 7 is set to be larger than the sliding resistance of the oil seal 8 with the cylinder hole 3d, it is affected by the oil seal 8 when braking is released. The piston 5 can be rolled back satisfactorily.

Further, by forming the dust seal portion 7a on the inner peripheral portion on the cylinder hole opening side of the piston seal 7 on the rollback portion 7c, it is possible to prevent dust from entering the cylinder hole by using the piston seal 7. .. Further, since the peripheral groove 7b is provided between the dust seal portion 7a and the rollback portion 7c, the dust seal portion 7a and the rollback portion 7c can easily act independently of each other. Further, since the non-contact portion 7g that does not contact the groove outer peripheral wall 3h is formed on the outer peripheral portion of the cylinder hole opening side surface 7f, the tension applied to the dust seal portion 7a can be suppressed to a small value, and the rollback portion 7c can be used. When the piston 5 is rolled back, there is no risk of being affected by the dust seal portion 7a.

Further, since the notch portion 7e is provided on the inner peripheral surface of the rollback portion 7c of the piston seal 7, air is released from the notch portion 7e when assembling the piston seal 7, and the assembling property of the piston seal 7 is improved. It can be improved.

Further, since the caliper body 3 of the present embodiment is formed by the die casting method, the finishing process of the caliper body 3 can be simplified and the processing cost can be reduced.

8 to 10 show other embodiments of the present invention, and the same reference numerals are given to those showing the same components as those of the first embodiment, and detailed description thereof will be omitted. ..

8 and 9 are views showing a second embodiment of the present invention, in which the piston seal groove 3j of the present embodiment is recessed toward the bottom side of the cylinder hole on the outer peripheral side of the side wall 3k of the bottom of the cylinder hole. A groove of 3 m is provided around the circumference.

The piston seal 9 has a protrusion 9b formed in the concave groove 3m on the side surface 9a of the bottom of the cylinder hole. When the protrusion 9b is inserted into the concave groove 3m and no hydraulic pressure is applied, as shown in FIG. 8, the protrusion 9b is located between the outer peripheral wall 3n, the inner peripheral wall 3p, and the cylinder hole bottom side wall 3q of the concave groove 3m, respectively. A gap is formed, and the groove is in a non-contact state with the groove 3 m. Further, when a hydraulic load is applied, as shown in FIG. 9, as the rollback portion 7c is deformed, the inner peripheral surface 9c of the protrusion 9b and the inner peripheral wall 3p of the concave groove 3m are in contact with each other. ..

In this embodiment, as described above, when the hydraulic pressure is not applied, the protrusion 9b is in a non-contact state with the concave groove 3m, so that the piston seal 9 can be satisfactorily assembled into the piston seal groove 3j. Further, when the hydraulic load is applied, the protrusion 9b comes into contact with the concave groove 3m, so that the shearing force of the rollback portion 7c of the piston seal 9 can be increased, and the piston 5 can be satisfactorily rolled back when the braking is released. ..

FIG. 10 shows a third embodiment of the present invention. In the piston seal 10 of the present embodiment, a metal annular member 11 is molded on the bottom side of the cylinder hole. As a result, the shearing force and the tense force on the bottom side of the cylinder hole of the piston seal 10 can be increased, and the piston can be satisfactorily rolled back by the rollback portion 7c of the piston seal 10 when the braking is released.

The piston seal of the present invention is not limited to each of the above-described examples, and may not be provided with a dust seal portion, and a non-contact portion that does not come into contact with the outer peripheral wall of the groove on the outer peripheral portion on the cylinder hole opening side. It does not have to be provided. Further, the notch portion may not be provided on the inner peripheral surface of the rollback portion. Further, the caliper body of the present invention is not limited to the one formed by the die casting method. Further, the present invention can be applied not only to the pin slide type disc brake but also to the piston opposed type disc brake.

1 ... Vehicle disc brake, 2 ... Disc rotor, 3 ... Caliper body, 3a ... Acting part, 3b ... Reaction part, 3c ... Bridge part, 3d ... Cylinder hole, 3e ... Reaction force claw, 3f ... Piston seal groove, 3g ... Cylinder hole bottom side wall, 3h ... Groove outer wall, 3i ... Notch, 3j ... Piston seal groove, 3k ... Cylinder hole bottom side wall, 3m ... Recessed groove, 3n ... Outer wall, 3p ... Inner peripheral wall, 3q ... Cylinder hole bottom Side wall, 4 ... Friction pad, 4a ... Lining, 4b ... Back plate, 5 ... Piston, 5a ... Oil seal groove, 5b ... Cylinder hole bottom side wall, 5c ... Cylinder hole opening side wall, 5d ... Groove inner peripheral wall, 6 ... Liquid Pressure chamber, 7 ... Piston seal, 7a ... Dust seal part, 7b ... Circumferential groove, 7c ... Rollback part, 7d ... Cylinder hole bottom side surface, 7e ... Notch part, 7f ... Cylinder hole opening side surface, 7g ... Non-contact part, 8 ... oil seal, 9 ... piston seal, 9a ... cylinder hole bottom side surface, 9b ... protrusion, 9c ... inner peripheral surface, 10 ... piston seal, 11 ... annular member

Claims (7)

In a vehicle disc brake in which a piston that pushes a friction pad toward the side surface of the disc rotor is inserted in the cylinder hole formed in the caliper body.
An oil seal groove is provided on the outer peripheral surface of the piston on the bottom side of the cylinder hole, and an oil seal for sealing brake oil is fitted in the oil seal groove. A piston seal groove having a groove outer peripheral wall is provided around the piston seal groove, and a piston seal having a rollback portion for rolling back the piston when braking is released is fitted into the piston seal groove.
The piston return force for rolling back the piston of the rollback portion is set to be larger than the sliding resistance of the oil seal with the cylinder hole .
The piston seal groove is provided with a concave groove that is concave toward the bottom side of the cylinder hole on the outer peripheral side of the side wall of the bottom of the cylinder hole, and the piston seal is inserted into the concave groove on the side surface of the bottom of the cylinder hole. A disc brake for a vehicle, characterized in that a protrusion is formed, and the protrusion does not contact the concave groove when no hydraulic pressure is applied, and abuts the concave groove when a hydraulic pressure is applied. The piston seal is characterized in that a dust seal portion formed by gradually projecting the inner peripheral surface toward the side surface of the cylinder hole opening toward the inner peripheral side is provided on the inner peripheral portion on the cylinder hole opening side of the rollback portion. The vehicle disc brake according to claim 1. The vehicle disc brake according to claim 2, wherein a peripheral groove is provided between the rollback portion and the dust seal portion. The vehicle disc brake according to any one of claims 1 to 3, wherein the piston seal is provided with a non-contact portion that does not come into contact with the groove outer peripheral wall on the outer peripheral portion on the cylinder hole opening side. The vehicle disc brake according to any one of claims 1 to 4, wherein the piston seal is provided with a notch portion communicating with the disc axial direction on the inner peripheral surface of the rollback portion. The vehicle disc brake according to any one of claims 1 to 5, wherein the piston seal is formed by molding a metal annular member on the rollback portion. The vehicle disc brake according to any one of claims 1 to 6 , wherein the caliper body is formed by a die casting method.

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