JP5394947B2 - Dust seal for vehicle disc brake - Google Patents

Description

  The present invention relates to a dust seal for a vehicular disc brake that is disposed on a cylinder hole opening side of a caliper body and prevents dust from entering the cylinder hole.

  The vehicular disc brake is configured to slidably contact the outer peripheral surface of the piston with the inner peripheral surface of the cylinder hole so as to move the piston and roll the piston after releasing the braking force by a predetermined amount so that the friction pad, the disc rotor, Some piston seals have a function of automatically adjusting the gap between them and a dust seal that slides on the outer peripheral surface of the piston to prevent dust from entering the cylinder hole. As this dust seal, an annular base portion accommodated in a dust seal fitting groove formed in the cylinder hole and a lip portion protruding from the annular base portion toward the cylinder hole opening side are integrally provided, and the inner peripheral surface of the annular base portion and the piston A gap is formed between the outer peripheral surface of the piston and the inner peripheral surface of the lip portion and the outer peripheral surface of the piston are in sliding contact with each other so that the tight force of the dust seal does not affect the rollback amount of the piston seal. (For example, refer to Patent Document 1).

JP 2008-180363 A

  However, in the above-mentioned patent document, a gap is formed between the inner peripheral surface of the annular base portion of the dust seal and the outer peripheral surface of the piston in the non-braking state. As the lip portion is dragged by the piston, the annular base portion falls within the dust seal fitting groove, and the tightening force of the dust seal may increase and deform. For this reason, when the braking is released, the restoring force of the annular base portion may affect the rollback amount of the piston seal.

  Accordingly, the present invention provides a dust seal for a vehicle disc brake that has a simple structure and reliably prevents dust from entering the cylinder hole and does not affect the rollback of the piston after the brake is released. It is an object.

In order to achieve the above object, the dust seal of the vehicle disc brake of the present invention is fitted in a dust seal fitting groove formed at the opening end of the cylinder hole provided in the caliper body, and the piston hole is interposed in the cylinder hole. In a dust seal of a vehicle disc brake that slides into contact with the outer peripheral surface of a piston inserted therein to prevent dust from entering the cylinder hole, the dust seal is accommodated on the cylinder hole bottom side of the dust seal fitting groove. An annular base portion, an inner circumferential lip portion projecting from the inner circumferential side of the annular base portion to the cylinder hole opening side, a projecting portion from the outer circumferential side of the annular base portion to the cylinder hole opening side, and accommodated in the dust seal fitting groove. And an inner peripheral surface of the inner peripheral lip portion is formed in a conical surface shape that gradually decreases in diameter toward the tip side, With the convex portion is protruded on the inner circumferential side to the base end portion of the Jo base tip of the inner peripheral lip portion projects into the cylinder bore opening side of the cylinder bore open side of the dust seal fitting groove, the tip inner surface and said convex portions abut respectively on the outer circumferential surface of the piston, the outer circumferential surface of the front Kigaishu side lip is formed in a conical shape that gradually becomes larger in diameter toward the distal end side, the outer peripheral side lip The front end side of the outer peripheral side of the part contacts the outer peripheral surface of the dust seal fitting groove, and the front end surface of the outer peripheral side lip part contacts the side surface of the cylinder hole opening. It can also be formed on the inner peripheral side of the base end portion of the base portion in the circumferential direction.

  According to the dust seal of the disc brake for a vehicle of the present invention, since the inner surface of the tip of the inner peripheral lip is in contact with the outer peripheral surface of the piston, it is possible to reliably prevent dust from entering the cylinder hole. . Further, the dust seal has an inner peripheral lip except for the convex portion provided on the inner peripheral side of the annular base and the inner surface of the tip end portion of the inner peripheral lip portion on the outer peripheral surface of the piston, and excluding the convex portion and the inner surface of the tip portion. Since a gap is formed between the inner peripheral surface of the cylinder and the inner peripheral surface of the annular base and the outer peripheral surface of the piston, sliding resistance with the piston can be reduced, and the dust seal is opened in the cylinder hole during braking. It can be prevented from being dragged to the side. Thereby, it is possible to prevent a large tension force from being applied to the dust seal, and the dust seal does not affect the rollback of the piston after the brake is released.

  The outer peripheral lip portion is formed in a conical surface with an outer peripheral surface gradually increasing in diameter toward the distal end side, and the distal end side contacts the outer peripheral surface of the dust seal fitting groove and the side surface of the cylinder hole opening. Thus, the posture of the dust seal can be favorably maintained during braking. Furthermore, the front end side of the inner peripheral lip portion protrudes more toward the cylinder hole opening side than the cylinder hole opening side surface of the dust seal fitting groove, so that the convex portion that contacts the outer peripheral surface of the cylinder hole and the inner peripheral lip portion The tip end side that contacts the dust seal fitting groove of the outer peripheral lip portion is located at the intermediate position in the cylinder axial direction on the inner surface of the tip end portion of the tip, and the posture of the dust seal can be maintained better during braking. Further, by forming the convex portion in the circumferential direction on the inner peripheral side of the base end portion of the annular base portion, the contact area with the outer peripheral surface of the piston is reduced, and the sliding resistance with the piston is further increased. Can be reduced.

It is explanatory drawing of the dust seal | sticker which shows one example of this invention. It is a cross-sectional perspective view of a dust seal. It is a perspective view of a dust seal similarly. It is a sectional view of a disk brake similarly. It is explanatory drawing which shows the state at the time of the braking of the dust seal which has not provided the convex part in the cyclic | annular base part.

  FIG. 4 is a diagram showing an example of a vehicle disc brake to which the dust seal of the present invention is applied. A hydraulic type vehicle disc brake 1 includes a disc rotor 2 that rotates integrally with a wheel (not shown), and the disc rotor. 2 comprises a caliper body 3 attached to the vehicle body at one side, and a pair of friction pads 4 and 4 disposed facing each other with the disc rotor 2 sandwiched inside the caliper body 3.

  The caliper body 3 is composed of an action part 3a and a reaction part 3b that are arranged opposite to each side of the disk rotor 2, and a bridge part 3c that straddles the outer periphery of the disk rotor 2, and includes the action part 3a. A cylinder hole 6 in which the piston 5 is accommodated is provided, and a reaction force claw 3d is provided in the reaction portion 3b. A hydraulic chamber 7 is defined in the cylinder hole 6 between the piston 5 and the bottom of the cylinder hole 6.

  An annular piston seal fitting groove 6a is provided around the inner peripheral surface of the cylinder hole 6 at an axially intermediate portion, and an annular dust seal is fitted closer to the cylinder hole opening side than the piston seal fitting groove 6a. A groove 6b is provided around. The piston seal fitting groove 6a is fitted with a piston seal 8 which is in fluid-tight sliding contact with the outer peripheral surface 5a of the piston 5 and rolls back the piston 5 with its restoring force. The dust seal fitting groove 6b is fitted with the piston seal fitting groove 6a. A dust seal 9 that is in sliding contact with the outer peripheral surface 5 a of the piston 5 and that prevents dust from entering the cylinder hole 6 is fitted.

  The piston seal 8 is formed of an elastic material such as a rubber material having a quadrangular cross section, and the piston 5 is released after the braking force is released by taking into account its hardness and compression force and the friction coefficient and shape of the inner peripheral surface that is in sliding contact with the piston 5. Is formed so that a predetermined amount can be rolled back.

  The dust seal 9 is formed of an elastic material such as a rubber material equivalent to the piston seal 8, and includes an annular base portion 9a accommodated on the cylinder hole bottom side of the dust seal fitting groove 6b, and an inner periphery of the annular base portion 9a. From the outer peripheral side of the annular base portion 9a, and an inner peripheral lip portion 9c that protrudes from the side toward the cylinder hole opening side, and a tip end portion 9b protrudes more toward the cylinder hole opening side than the cylinder hole opening side surface 6c of the dust seal fitting groove 6b. It is integrally provided with an outer peripheral side lip portion 9d that protrudes toward the cylinder hole opening side and is accommodated in the dust seal fitting groove 6b. The inner peripheral lip portion 9c is formed in a conical surface shape in which the inner peripheral surface 9e gradually decreases in diameter toward the tip end portion 9b, and the outer peripheral side lip portion 9d is formed such that the outer peripheral surface 9g faces the outer peripheral end portion 9h. Thus, it is formed in a conical surface shape having a gradually increasing diameter. The annular base portion 9a is formed by dividing six convex portions 9f in the circumferential direction on the inner peripheral side of the base end portion.

  When the dust seal 9 is accommodated in the dust seal fitting groove 6b, the convex portion 9f of the annular base portion 9a and the inner surface of the tip end portion 9b of the inner peripheral lip portion 9c are formed on the outer peripheral surface 5a of the piston 5 as shown in FIG. A gap E is formed between the inner peripheral surface 9e of the inner peripheral lip portion 9c and the inner peripheral surface of the annular base portion 9a excluding the convex portion 9f and the inner surface of the tip end portion 9b, and the outer peripheral surface 5a of the piston 5. Is formed. The outer peripheral lip portion 9d has an outer peripheral end 9h of the outer peripheral surface 9g abutting on the outer peripheral surface 6d of the dust seal fitting groove 6b, and the outer peripheral end surface 9i is a cylinder hole opening side surface 6c of the dust seal fitting groove 6b. Abut. Further, the outer peripheral side tip portion 9h of the outer peripheral side lip portion 9d is in contact with the outer peripheral surface 6d of the dust seal fitting groove 6b, and the outer peripheral side tip surface 9i is in contact with the cylinder hole opening side surface 6c of the dust seal fitting groove 6b. The position in the axial direction is such that the convex portion 9f of the annular base portion 9a contacts the outer peripheral surface 5a of the piston 5 and the position where the inner surface of the tip end portion 9b of the inner peripheral lip portion 9c contacts the outer peripheral surface 5a of the piston 5. It is arranged between.

  In the vehicular disc brake 1 formed in this way, when hydraulic fluid whose pressure has been increased is supplied to the hydraulic pressure chamber 7 of the caliper body 3 by the driver's braking operation, the piston 5 advances the cylinder hole 6 toward the disc rotor. Then, one friction pad 4 is pressed against one side of the disk rotor 2. Next, this reaction causes the caliper body 3 to move toward the action portion 3a while being guided by a slide pin (not shown), and the reaction force claw 3d of the reaction portion 3b moves the other friction pad 4 to the disc. A braking action is performed by pressing against the other side of the rotor 2. At this time, the piston seal 8 is dragged to the outer peripheral surface 5a by the advance of the piston 5 during braking, and is elastically deformed toward the cylinder hole opening side.

  On the other hand, in the dust seal 9, only the inner surface of the convex portion 9f of the annular base portion 9a and the inner surface of the tip portion 9b of the inner peripheral lip portion 9c abuts on the outer peripheral surface 5a of the piston 5, Since a gap E is formed between the inner peripheral surface of the peripheral lip 9c and the inner peripheral surface of the annular base 9a and the outer peripheral surface 5a of the piston 5, the sliding resistance with the piston 5 is reduced. The convex portion 9f of the annular base portion 9a and the distal end portion 9b of the inner peripheral lip portion 9c abut against the outer peripheral surface 5a of the piston 5, and the distal end side of the outer peripheral surface 9g of the outer peripheral lip portion 9d is the dust seal fitting groove 6b. 1 can be maintained in contact with the outer peripheral surface 6d, and the outer peripheral end surface 9i is in contact with the cylinder hole opening side surface 6c of the dust seal fitting groove 6b. Keep force F1 small Door can be.

  On the other hand, as shown in FIG. 5, in the case of a dust seal that does not have a convex portion on the inner peripheral side of the annular base portion 9 a, the annular lip portion 21 a on the inner peripheral side of the dust seal 21 is The inner peripheral surface side of the base portion 21b is also dragged toward the cylinder hole opening side, and the annular base portion 21b falls in the dust seal fitting groove 6b, so that the inner peripheral surface 21c of the annular base portion 21b and the outer peripheral surface 5a of the piston 5 are in contact with each other. Since the contact area increases, the sliding resistance increases and the tension force F2 increases.

  When braking is released and the pressure in the hydraulic chamber 7 decreases, the piston 5 rolls back by a predetermined amount due to the restoring force of the piston seal 8 returning to its original shape, and the caliper body 3 slides to the reaction portion side and returns to the original position. At the same time, the friction pads 4 and 4 are separated from the disk rotor 2. At this time, since the tightening force F <b> 1 applied to the dust seal 9 can be kept small as described above, the piston 5 can be rolled back without being affected by the dust seal 9. Furthermore, as the piston 5 moves backward, the tip 9b of the inner peripheral lip 9c of the dust seal 9 comes into sliding contact with the outer peripheral surface 5a of the piston 5, thereby efficiently removing dust adhering to the tip of the piston 5. Intrusion of dust into the cylinder hole 6 can be reliably prevented.

  As described above, the dust seal of the present invention is not limited to being formed of an elastic material such as a rubber material equivalent to the piston seal, but may be formed of a hard resin material having a low friction coefficient such as nylon. . Moreover, the convex part provided in the annular base part of a dust seal may be formed over the perimeter of the base end part inner peripheral side of an annular base part. Furthermore, the dust seal of the present invention is not limited to the one applied to the pin slide type disc brake as in the above-described embodiment, and can be applied to any type of disc brake, and the number of pistons is arbitrary. .

  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 ... Friction pad, 5 ... Piston, 5a ... Outer periphery 6: Cylinder hole, 6a ... Piston seal fitting groove, 6b ... Dust seal fitting groove, 6c ... Cylinder hole opening side surface, 6d ... Outer peripheral surface, 7 ... Hydraulic chamber, 8 ... Piston seal, 9 ... Dust seal, 9a ... annular base part, 9b ... tip part, 9c ... inner peripheral lip part, 9d ... outer peripheral lip part, 9e ... inner peripheral face, 9f ... convex part, 9g ... outer peripheral face, 9h ... outer peripheral side tip part, 9i ... outer peripheral part Side tip surface, 21 ... dust seal, 21a ... lip, 21b ... annular base, 21c ... inner peripheral surface

Claims (2)

Fits in a dust seal fitting groove formed at the opening side tip of the cylinder hole provided in the caliper body, and slides into the cylinder hole and is inserted into the cylinder hole through a piston seal. In the dust seal of the vehicle disc brake that prevents the intrusion of dust,
The dust seal includes an annular base portion accommodated on the cylinder hole bottom side of the dust seal fitting groove, an inner peripheral lip portion protruding from the inner peripheral side of the annular base portion toward the cylinder hole opening side, and an outer peripheral side of the annular base portion Projecting from the cylinder hole opening side and integrally including an outer peripheral lip portion accommodated in the dust seal fitting groove,
The inner peripheral surface of the inner peripheral lip portion is formed in a conical surface shape that gradually becomes smaller in diameter toward the distal end side, and a convex portion is formed to protrude on the inner peripheral side of the base end portion of the annular base portion. The tip end portion of the inner peripheral lip portion protrudes to the cylinder hole opening side from the cylinder hole opening side surface of the dust seal fitting groove, and the tip end inner surface and the convex portion are in contact with the outer peripheral surface of the piston, respectively.
The outer peripheral surface of the outer peripheral lip portion is formed in a conical surface shape that gradually increases in diameter toward the distal end side, and the outer peripheral side distal end side of the outer peripheral side lip portion abuts on the outer peripheral surface of the dust seal fitting groove, A dust seal for a disk brake for a vehicle, wherein a front end surface of the outer peripheral lip portion is in contact with a side surface of the cylinder hole opening . 2. The dust seal for a vehicle disc brake according to claim 1 , wherein the convex portion is formed by being divided in the circumferential direction on the inner peripheral side of the base end portion of the annular base portion .

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