JP2006283948A - Disk brake for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To miniaturize a caliper body by shortening length in the disk axis direction of a cylinder bore while assuring length of disk axial direction required to a piston and a plug. <P>SOLUTION: A cylinder bore 3d is formed by screwing a plug 6 to a larger diameter part 3j of a through hole 3i formed on the caliper body 3. In the outer periphery of a bottom wall 5a of the piston 5, an annular protuberance part 5c projecting on opposed disk rotor side by succeeding on circumferential wall 5b of the piston 5 is provided. On the outer peripheral side of disk rotor side end of the plug 6, an abutting part 6b which abuts to a stepped part 3k between the smaller diameter part 3i and the larger diameter part 3j is formed, and on the peripheral side located more inner than the abutting part 6b, an annular recessed part 6c which the annular protuberance part 5c of the piston 5 can enter is formed. In the center of the opposed disk rotor side of the plug 6, a tool insertion recessed part 6f for inserting a screwing tool 7 is formed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a hydraulic disk brake for use in a traveling vehicle such as an automobile or a motorcycle. More specifically, the present invention relates to a cylinder hole formed in a caliper body with a through hole and an anti-disk rotor side of the through hole. The present invention relates to a disc brake for a vehicle formed with a closing plug.

  Conventionally, in a disc brake in which a cylinder hole formed in a caliper body is formed by a through-hole in the disc axial direction provided in the disc axial direction and a plug body that liquid-tightly closes the counter-rotor side of the through-hole, The through hole includes a large diameter portion on the side opposite to the disk rotor and a small diameter portion on the disk rotor side, and the plug is screwed to the large diameter portion via a sealing material. In the cylinder hole thus formed, a piston is inserted through a piston seal, and a hydraulic chamber is provided between the bottom wall of the piston and the bottom of the cylinder hole.

Further, a tool insertion recess for inserting a screwing tool is formed on the side of the plug body opposite to the disc rotor. By inserting and rotating the screwing tool into the tool insertion recess, the plug becomes a large diameter portion. Detachable (see, for example, Patent Documents 1 to 3).
Japanese Utility Model Publication No. 6-69456 JP 2003-120729 A JP 2003-172383 A

  However, the cylinder hole and piston of the disc brake as described above are used to securely hold the piston in the cylinder hole even when the friction pad is fully worn and the protruding amount of the piston becomes large. Had to secure the length of direction. Further, the plug body also needs to be provided with a male screw and a seal portion for screwing on the large-diameter portion on the peripheral wall, and on the side opposite to the disc rotor, a tool insertion recess for inserting a screwing tool is formed. The length in the disk axial direction had to be secured, and the cylinder axial direction of the caliper body was long.

  Accordingly, the present invention provides a vehicle disc capable of reducing the caliper body size by reducing the length of the cylinder hole in the disc axial direction while ensuring the length in the disc axial direction necessary for the piston and the plug. The purpose is to provide a brake.

  In order to achieve the above object, in the first aspect of the present invention, a through hole having a small diameter portion on the disk rotor side and a large diameter portion on the opposite disk rotor side is formed in the disk axial direction in the working portion of the caliper body. A plug body that closes the through hole is screwed into the large diameter portion to form a cylinder hole, a piston is inserted into the cylinder hole, and a hydraulic chamber is provided between the bottom wall of the piston and the plug body. In the vehicular disc brake, the piston is provided with an annular protrusion on the outer periphery of the bottom wall, which protrudes toward the disc rotor side continuously from the peripheral wall of the piston, and the plug body has an outer periphery on the disc rotor side. A contact portion that contacts the step portion between the small diameter portion and the large diameter portion, and forming an annular concave portion into which the annular convex portion of the piston can be inserted on the inner peripheral side with respect to the corresponding contact portion, In the center of the plug body on the side opposite to the disk rotor, a screwing tool It is characterized by forming the tool insertion recess to be inserted.

  In a second aspect of the present invention, the plug body is characterized in that the inner peripheral side of the stopper is located on the side opposite to the disc rotor than the contact portion.

  In a third aspect of the present invention, the piston has a spherical convex portion formed on the bottom wall on the inner peripheral side of the annular convex portion, the spherical convex portion not projecting toward the disc rotor side from the annular convex portion, and the plug body is a disc A spherical concave portion having a shape along the spherical convex portion is formed on the inner peripheral side of the annular concave portion on the rotor side, and a plug corresponding to the spherical concave portion is formed at the bottom of the tool insertion concave portion on the counter disk rotor side. Forming a body-side spherical convex portion, and the screwing tool includes a tool-side spherical concave portion having a shape along the plug-side spherical convex portion on a distal end surface, and an outer peripheral side of the tool-side spherical concave portion and the plug-side spherical convex portion. The plug body is rotated by engaging with the outer peripheral side.

  According to the first invention, the piston can ensure the length in the disk axial direction by the annular convex portion provided on the outer periphery of the bottom wall. Moreover, since the said annular convex part can be inserted in the annular recessed part formed in the stopper, the length of a cylinder hole can be shortened and a caliper body can be reduced in size.

  According to the second invention, when the piston moves backward, the annular convex portion enters the annular concave portion between the inner circumferential side from the annular convex portion of the piston and the inner circumferential side from the annular concave portion of the plug body. A hydraulic chamber can be secured without abutting forward.

  According to the third invention, the strength of the piston can be ensured by providing the spherical convex portion on the bottom wall of the piston. In addition, since the spherical recess is formed on the disk rotor side of the plug and the plug-side spherical convex is formed at the bottom of the tool insertion recess, the cylinder axial direction of the plug is secured while securing the fitting allowance of the screwing tool. As a result, the caliper body can be miniaturized.

  Embodiments of the present invention applied to a front disc brake of a bar handle vehicle such as a motorcycle will be described below with reference to the drawings. 1 and 2 show a first embodiment of the present invention. FIG. 1 is an enlarged sectional view taken along the line II in FIG. 2, and FIG. 2 is a front view of a disc brake.

  The hydraulic disc brake 1 includes a wheel (not shown), a disc rotor 2 that rotates integrally in the direction of arrow A when the vehicle moves forward, a monobody type caliper body 3 that is attached to the vehicle body at one side of the disc rotor 2, The caliper body 3 is composed of a pair of friction pads 4 and 4 that are opposed to each other with the disc rotor 2 interposed therebetween.

  The caliper body 3 is integrally formed with a pair of action portions 3a and 3b disposed on both sides of the disk rotor 2 and a bridge portion 3c connecting the outer periphery of the disk rotor 2 to connect the action portions 3a. , 3b are formed with two cylinder holes 3d, 3e for interposing the piston 5, respectively. Also, one working portion 3a is integrally formed with boss portions 3f, 3f for mounting the vehicle body, and the caliper body 3 is attached to the vehicle body by bolting the boss portions 3f, 3f for mounting the vehicle body to the vehicle body. It is attached.

  Each piston 5 is formed in a cup shape, is inserted in the cylinder holes 3d and 3e with the opening side facing the disk rotor 2, and is placed on the outer periphery of the bottom wall 5a continuously with the peripheral wall 5b of the piston 5. An annular convex portion 5c that protrudes toward the rotor is provided. Further, an annular recess 5d is provided on the inner peripheral side of the annular convex portion 5c of the bottom wall 5a, and further, a spherical convex portion 5e in which the central portion of the bottom wall 5a protrudes spherically on the inner peripheral side. However, it is formed so as not to protrude to the side opposite to the disc rotor than the annular convex portion 5c.

  Each of the cylinder holes 3d and 3e is finished by casting a cast hole after casting, but there is no space for inserting a cutting tool between the action parts 3a and 3b. Each cylinder hole 3e provided in the other action portion 3b is formed by cutting through the machining hole. Each cylinder hole 3e formed in the other action portion 3b is cut by a known method, and a boot groove 3g and a piston seal groove 3h are formed on the opening side.

  Each cylinder hole 3d provided in one action part 3a is formed by closing the counter-rotor side of a through hole formed by cutting the processed hole with a plug body 6. The through hole is a stepped hole having a small diameter portion 3i on the disk rotor side and a large diameter portion 3j on the opposite disk rotor side, and a step portion 3k is formed between the small diameter portion 3i and the large diameter portion 3j. A boot groove 3m and a piston seal groove 3n are formed on the disk rotor side of the small diameter portion 3i, a seal groove 3o is formed on the disk rotor side of the large diameter portion 3j, and a female screw 3p is formed on the counter disk rotor side. ing.

  The plug body 6 is formed in a disk shape having a predetermined thickness, and a male screw 6a that is screwed with the female screw 3p is formed on the outer periphery. An abutting portion 6b that abuts the stepped portion 3k is provided on the outer peripheral side of the disc rotor side end portion of the plug body 6, and the annular convex portion of the piston 5 is located on the inner peripheral side of the corresponding contacting portion 6b. An annular recess 6c into which 5c can enter is formed. A convex portion 6d is provided on the inner peripheral side of the annular concave portion 6c so as to follow the shape of the annular concave portion 5d of the piston 5, and the convex portion 6d is located closer to the disc rotor than the contact portion 6b. It is formed so as not to protrude. A spherical concave portion 6e is formed on the inner peripheral side of the convex portion 6d so as to follow the shape of the spherical convex portion 5e of the piston 5.

  A tool insertion recess 6f for inserting the screwing tool 7 is formed at the center of the plug body 6 on the side opposite to the disk rotor. The tool insertion concave portion 6f is a bottomed hole formed in a substantially hexagonal star shape, and a plug-side spherical convex portion 6g corresponding to the shape of the spherical concave portion 6e is formed in the bottom portion. The screwing tool 7 has a substantially hexagonal star-shaped tip shaft portion 7a that can be inserted into the tool insertion concave portion 6f, and a plug-side spherical convex portion of the tool insertion concave portion 6f is formed on the tip surface of the tip shaft portion 7a. A tool-side spherical recess 7b is formed along the shape of 6g. The screwing tool 7 fits the tip shaft portion 7a into the tool insertion recess 6f, rotates the screwing tool 7 to rotate the plug body 6, and attaches and detaches the plug body 6 to and from the large diameter portion 3j.

  The cylinder hole 3d of the one action portion 3a has the seal material 8 fitted in the seal groove 3o of the large diameter portion 3j, the male screw 6a of the plug 6 is screwed into the female screw 3p, and the contact portion 6b is in contact with the step portion 3k. The boot 9 is fitted in the boot groove 3m, and the piston seal 10 is fitted in the piston seal groove 3n. The boot 11 is fitted in the boot groove 3g of the cylinder hole 3e of the other action portion 3b, and the piston seal 12 is fitted in the piston seal groove 3h. The piston 5 is inserted into each of the cylinder holes 3d and 3e formed in this way, and the disk rotor side end portion of the plug body 6 and the piston are inserted into the cylinder hole 3d formed in one action portion 3a. 5 is defined between the bottom wall 5a of the cylinder 5 and the hydraulic chamber 14 is defined between the bottom 3q of the cylinder hole 3e and the bottom wall 5a of the piston 5 in the other cylinder hole 3e. Made.

  Since the present embodiment is formed as described above, the piston 5 can secure the length in the disk axial direction by the annular protrusion 5c, and the cylinder hole 3d can be used even when the friction pad 4 is fully worn. The piston 5 can be securely held inside. Further, when the piston 5 is retracted when the friction pad 4 is new, the annular convex portion 5c and the spherical convex portion 5e of the piston 5 can enter the annular concave portion 6c and the spherical concave portion 6e of the plug body 6, respectively. The length of the hole 3d in the disk axial direction can be shortened, and the caliper body 3 can be downsized.

  Further, by engaging the outer peripheral side of the tool-side spherical concave portion 7b provided in the screwing tool 7 with the outer peripheral side of the plug-side spherical convex portion 6g provided in the tool insertion concave portion 6f of the plug body 6, the screwing tool While securing the fitting allowance, the thickness of the plug body 6 in the cylinder axial direction can be made as thin as possible, and the caliper body 3 can be downsized.

  FIG. 3 is an explanatory view of a disc brake and a screwing tool showing a second embodiment of the present invention. The same members as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The piston 20 of the present embodiment is provided with an annular protrusion 20c that protrudes toward the counter-disk rotor side continuously from the peripheral wall 20b of the piston 20 on the outer peripheral side of the bottom wall 20a. The inner peripheral side is a concave portion 20d.

  As in the first embodiment, the plug body 21 of the present embodiment is formed with a male screw 21a screwed with the female screw 3p formed on the large diameter portion 3j on the outer periphery, and the outer periphery of the end portion of the plug body 21 on the disk rotor side. On the side, a contact portion 21b that contacts the stepped portion 3k is provided. An annular concave portion 21c into which the annular convex portion 20c of the piston 20 can enter is formed on the inner peripheral side of the contact portion 21b, and the concave portion 20d of the piston 20 is formed on the inner peripheral side of the annular concave portion 21c. The cylindrical convex portion 21d is formed so as not to protrude from the contact portion 21b to the disc rotor side so as to follow the shape. In addition, a substantially star-shaped tool insertion recess 21 e into which the screwing tool 22 is inserted is formed at the center of the plug body 21 on the side opposite to the disk rotor.

  The screwing tool 22 has a substantially hexagonal star-shaped tip shaft portion 22a that can be inserted into the tool insertion recess 21e, and the tip surface of the tip shaft portion 22a is formed in a flat shape corresponding to the tool insertion recess 21e. Has been.

  In this embodiment, the tool insertion recess 21e is formed by using a convex portion 21d that protrudes toward the disk rotor side, so that the cylinder shaft of the plug body 21 is secured while securing the fitting allowance of the screwing tool 22. The thickness in the direction can be made as thin as possible.

  The present invention is not limited to the one applied to the monobody type opposed type disc brake as in the above-described embodiments, but any type such as a split type disc brake or a pin slide type disc brake. It can also be applied to disc brakes.

It is II expanded sectional drawing of FIG. 1 is a front view of a disc brake showing a first embodiment of the present invention. It is explanatory drawing of the disc brake and screwing tool which shows the 2nd form example of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Disc brake, 2 ... Disc rotor, 3 ... Caliper body, 3a, 3b ... Action part, 3d, 3e ... Cylinder hole, 3g, 3m ... Boot groove, 3h, 3n ... Piston seal groove, 3i ... Through-hole, 3j ... small diameter part, 3k ... large diameter part, 3k ... step part, 3o ... seal groove, 3p ... female screw, 3q ... bottom part, 4 ... friction pad, 5, 20 ... piston, 5a, 20a ... bottom wall, 5b, 20b ... Peripheral wall, 5c, 20c ... annular convex part, 6, 21 ... plug, 6a, 21a ... male screw, 6b, 21b ... abutting part, 6c, 21c ... annular concave part, 6d, 21d ... convex part, 6e ... spherical concave part 6f, 21e ... tool insertion recess, 6g ... plug side spherical projection, 7, 22 ... screwing tool, 7a, 22a ... tip shaft, 7b ... tool side spherical recess, 8 ... seal material, 9, 11 ... boot 10, 12 ... Piston seal, 13, 14 ... Liquid Room

Claims (3)

In the caliper body working portion, a through hole having a small diameter portion on the disk rotor side and a large diameter portion on the opposite disk rotor side is formed in the disk axial direction, and the plug body closes the through hole in the large diameter portion. In a vehicle disc brake in which a cylinder hole is formed by screwing, a piston is inserted into the cylinder hole, and a hydraulic chamber is provided between the bottom wall of the piston and the plug body, the piston is An annular protrusion is provided on the outer periphery of the wall so as to continuously protrude from the peripheral wall of the piston to the side opposite to the disk rotor, and the plug is provided on the outer periphery on the disk rotor side between the small diameter portion and the large diameter portion. An annular recess that can be inserted into the piston on the inner circumferential side of the corresponding contact portion, and screwed into the center of the plug body on the side opposite to the disc rotor. Features a tool insertion recess for inserting tools Vehicle disc brake that. 2. The vehicle disc brake according to claim 1, wherein an inner circumferential side of the plug body is located on an opposite side of the disc rotor from the contact portion. The piston forms a spherical convex portion that does not protrude from the annular convex portion toward the side opposite to the disk rotor than the annular convex portion on the bottom wall on the inner peripheral side of the annular convex portion, and the plug body includes the annular concave portion on the disc rotor side. A spherical concave portion having a shape along the spherical convex portion is formed on the inner peripheral side, and a plug-side spherical convex portion having a shape corresponding to the spherical concave portion is formed at the bottom of the tool insertion concave portion on the anti-disk rotor side. The screwing tool is provided with a tool-side spherical concave portion having a shape along the plug-side spherical convex portion on the distal end surface, and the outer peripheral side of the tool-side spherical convex portion is engaged with the outer peripheral side of the plug-side spherical convex portion. The vehicle disc brake according to claim 1 or 2, wherein the stopper is rotated together.

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