JP2010038334A - Disk brake device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a disk brake device capable of suppressing generation of a drag phenomenon of a pad by suppressing relative displacement between a piston and a returning mechanism. <P>SOLUTION: The piston 15 is movably supported in a cylinder part 21 of a caliper 14. The piston 15 advances during pressurization to press friction pads 12, 13 to a disk rotor 11. The piston 15 can be returned to an initial position by a seal ring (returning mechanism) 28 provided for the cylinder part 21 during decompression. The seal ring 28 is composed of a movable element 33, a low-elastic member 34, and a high-elastic member 35. A regulation mechanism is provided for regulating relative displacement between the piston 15 and the seal ring 28. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a disc brake device in which a disc rotor that rotates integrally with a wheel is clamped by a friction pad so that a braking force is applied to the wheel via the disc rotor by frictional resistance thereof.

  In a general caliper floating type disc brake device, a caliper is supported by a mounting bracket so as to be movable in the direction of the axis of rotation of a wheel. In this case, the caliper is provided with a pair of slide pins, while the mounting bracket is provided with a pair of fitting holes into which the pair of slide pins are fitted, and the slide pins are slidably fitted into the fitting holes. The caliper is allowed to move. The caliper has a U-shape that straddles the disk rotor, and an inner pad (friction pad) is movably supported on one side, and an outer pad (friction pad) is fixed on the other side. The disk rotor is provided with an actuator having a piston for pressing the inner pad against the disk rotor on one side.

  Therefore, when the driver depresses the brake pedal, the actuator is actuated by the depressing force, the piston moves forward and presses the inner pad against the disc rotor, and the caliper moves by the reaction force that the piston moves forward, causing the outer pad to move to the disc rotor. Press. For this reason, the disc rotor is sandwiched between the pair of pads, so that a braking force can be applied to the wheels via the disc rotor.

  By the way, in the disc brake device described above, the piston is movably supported in the cylinder hole of the caliper and is liquid-tightly held by the piston seal, and the hydraulic fluid is supplied to the hydraulic chamber in the cylinder hole during braking. When the pressure is supplied, the piston moves forward while deforming the piston seal, and when releasing the hydraulic pressure from the hydraulic pressure chamber, the piston moves backward to the hydraulic pressure chamber side by the restoring force of the deformed piston seal. . However, when the brake pedal depressing force is excessive by the occupant, the piston is pushed into the disc rotor side more than a predetermined amount, relative movement occurs between the piston and the piston seal, and the piston is fully retracted by the restoring force of the piston seal. In other words, so-called dragging occurs in which the pad continues to contact the disk rotor. Then, a so-called knockback may occur in which the pad is repelled by the rotating disk rotor and pushes back the piston.

  As what solves such a problem, there exists a thing described in the following patent document 1, for example. In the disc brake device described in Patent Document 1, an annular ring mounting groove is formed in the inner hole of the cylinder, and a chamfered portion is formed on the pad side at an opening edge on the pad side of the ring mounting groove. A retraction ring that seals between the piston and cylinder and returns the piston when the pressure is released after braking is assembled in the ring mounting groove, and the cylinder has an annular recess that opens toward the pad side end wall of the ring mounting groove. In addition to forming, a deformation-permitting ring made of a compressible material and allowing the retraction ring to enter the annular recess is assembled in the annular recess. Therefore, since the hydraulic pressure at which the amount of deflection of the pad and cylinder, which increases as the hydraulic pressure increases, is larger than the amount of piston retracted by the retraction ring can be set to a high value, the hydraulic pressure is higher than before. Drag can be reduced to the area.

Japanese Patent Laid-Open No. 07-253128

  In the above-described conventional disc brake device, a ring mounting groove and a deformation-accepting ring made of a compressible material and allowing deformation into the annular recess of the retraction ring are assembled to reduce drag. Yes. However, when the pressure is released and the piston returns, the deformation is returned from the deformation allowing ring, and then the deformation of the retraction ring returns. Therefore, when the deformation of the deformation allowing ring returns, there is a possibility that relative movement occurs between the piston and the retraction ring, and the piston cannot be fully returned, and dragging may occur.

  The present invention solves such problems, and an object of the present invention is to provide a disc brake device capable of suppressing the occurrence of a pad drag phenomenon by suppressing relative movement between a piston and a return mechanism. .

  In order to solve the above-described problems and achieve the object, a disc brake device according to the present invention includes a disc rotor that rotates about a rotation axis, a friction pad that faces a friction surface of the disc rotor, and the friction pad. And a cylinder that supports the friction surface of the disk rotor so as to be able to approach and separate, a piston that can advance when pressed to press the friction pad against the disk rotor, and a low elastic member and a high elastic member. It is provided with the return mechanism which pulls back the piston at the time of pressure, and the control mechanism which controls relative movement of the piston and the return mechanism.

  In the disc brake device according to the present invention, the restricting mechanism prohibits relative movement between the piston and the high elastic member during elastic deformation of the low elastic member due to advance of the piston, and the high elastic member due to advance of the piston. Relative movement between the piston and the low-elasticity member is permitted during elastic deformation.

  In the disc brake device according to the present invention, the return mechanism is housed in a ring groove formed on the inner peripheral surface of the cylinder so as to face the outer peripheral surface of the piston, and is inserted into the ring groove so as to be movable relative to the piston. The movable element, the low elastic member mounted on the forward side of the piston in the movable element, and the high elastic member mounted on the backward side of the piston in the movable element and in close contact with the piston. It is characterized by that.

  In the disc brake device according to the present invention, the high-elasticity member is a cup-type seal member that can be deformed by turning when the piston moves forward.

  In the disc brake device according to the present invention, the return mechanism is housed in a ring groove formed on the inner peripheral surface of the cylinder so as to face the outer peripheral surface of the piston, and is inserted into the ring groove so as to be movable relative to the piston. The high elasticity member that extends to the retreat side of the piston and has a tip closely contacting the piston, and the low elasticity that is inserted into the ring groove and attached to the advance side of the piston in the high elasticity member And a member.

  In the disc brake device according to the present invention, the highly elastic member is a seal member that is compressible and deformable when the piston moves forward.

  According to the disk brake device of the present invention, a cylinder that supports the friction pad so as to be able to approach and separate from the friction surface of the disk rotor, a piston that can be advanced when pressed to press the friction pad against the disk rotor, and a low elastic member A return mechanism that has a highly elastic member and pulls back the piston when the pressure is released, and a restriction mechanism that restricts relative movement between the piston and the return mechanism are provided. Therefore, when the piston moves forward during pressurization, the restriction mechanism restricts the relative movement between the piston and the return mechanism, so that the low elastic member and the high elastic member are alternately elastically deformed. The elastic deformation of the elastic member and the highly elastic member is alternately released, and the return amount of the piston can be ensured appropriately, and the occurrence of the pad drag phenomenon can be suppressed.

  Embodiments of a disc brake device according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same.

  1 is a cross-sectional view illustrating a piston return mechanism in a disc brake device according to a first embodiment of the present invention, FIGS. 2 and 3 are cross-sectional views illustrating operations of the piston return mechanism of the first embodiment, and FIG. 4 is a piston. FIG. 5 is a cross-sectional view illustrating the disc brake device according to the first embodiment.

  Although not shown, the disc brake device of the first embodiment is a device that applies braking force to a wheel that is rotatably supported by a vehicle, and includes a disc rotor that is integrally rotatable with the wheel, and a vehicle body. It has a pair of friction pads which are provided on the side so as not to rotate relative to the wheels and sandwich the disk rotor so as to impart frictional resistance, and an actuator having a piston which presses the friction pad against the disk rotor.

  That is, as shown in FIG. 5, the disc brake device has a disc rotor 11 that rotates integrally with a wheel (not shown) and rotates around the axis of rotation of the axle, and friction surfaces on both sides of the disc rotor 11. A pair of opposing friction pads 12, 13, a caliper 14 that supports the pair of friction pads 12, 13 so as to be able to approach and separate from the friction surface of the disk rotor 11, and a pair of friction pads 12, 13 by a piston 15. 11 and a cylinder mechanism (actuator) 16 that can be pressed against the cylinder 11.

  More specifically, the caliper 14 has a U-shape straddling the disk rotor 11 and is mounted with a cylinder mechanism 16 that allows the piston 15 to move back and forth. The caliper 14 connects the cylinder part 21 in which the cylinder mechanism 16 is provided, the reaction part 22 disposed at a position facing the cylinder part 21 and the disk rotor 11, and the cylinder part 21 and the reaction part 22. It is comprised from the connection part 23. FIG.

  The caliper 14 is supported by a mounting bracket (not shown) fixed to the vehicle body so as to be movable along the rotational axis direction of the disk rotor 11, that is, in a direction orthogonal to the rotational direction.

  The pair of friction pads 12 and 13 disposed opposite to the friction surfaces on both sides of the disk rotor 11 are an inner pad 12 disposed on the cylinder portion 21 side in the caliper 14 and an outer pad 13 disposed on the reaction portion 22 side. It is. The inner pad 12 and the outer pad 13 are configured such that the base ends of the friction materials 24 and 25 are fixed to the back metal plates 26 and 27. The inner pad 12 is supported by a guide member (not shown) having a back metal 26 formed on the caliper 14. On the other hand, the back pad 27 of the outer pad 13 is fixed to the reaction part 22 in the caliper 14.

  The cylinder mechanism 16 is configured such that the piston 15 is movably supported by the cylinder portion 21 and a seal ring 28 that is in close contact with the outer surface of the piston 15 is attached to the inner surface of the cylinder portion 21. . A hydraulic chamber 29 is defined by the cylinder portion 21, the piston 15, and the seal ring 28, and the tip portion of the piston 15 faces the back metal 26 of the inner pad 12.

  Therefore, when hydraulic fluid is supplied to the hydraulic chamber 29 of the cylinder mechanism 16 and pressurized, the piston 15 moves forward in the direction of arrow A, and the front surface of the piston 15 presses the back metal 26 of the inner pad 12, and this inner pad. The front surface of 12 can be brought close to the friction surface of the disk rotor 11. At this time, the caliper 14 moves forward in the direction opposite to that of the piston 15 due to the moving reaction force of the piston 15 moving forward, that is, in the direction of the arrow B, and the pressing surface of the outer pad 13 approaches the friction surface of the disk rotor 11. Can be made.

  When the inner pad 12 and the outer pad 13 are pressed against each friction surface of the disk rotor 11, a frictional resistance force is generated between the inner pad 12 and the outer pad 13 and the rotating disk rotor 11. A braking force can be applied to the.

  In this case, the seal ring 28 attached to the cylinder portion 21 is in close contact with the piston 15, and when the piston 15 is pressurized, the piston 15 moves forward while deforming the seal ring 28. When the piston 15 is depressurized, the piston 15 is returned to a predetermined position by the restoring force of the deformed seal ring 28. When the piston moves backward, the inner pad 12 moves away from the disk rotor 11, the caliper 14 moves backward due to the moving reaction force of the piston 15 moving backward, and the outer pad 13 moves away from the disk rotor 11.

  In the disc brake device according to the first embodiment, as described above, the seal ring 28 functions as a return mechanism that pulls back the piston 15 when the pressure is released. Further, a low elastic member and a high elastic member are mounted on the mover, and a restriction mechanism for restricting relative movement between the piston 15 and the seal ring (return mechanism) 28 is provided.

  That is, as shown in FIG. 1, the cylinder portion 21 of the caliper 14 has a support hole 14a, and the outer peripheral surface 15a of the piston 15 is supported by the support hole 14a so as to be movable with a predetermined gap. . A first ring groove 31 that is continuous in the circumferential direction is formed on the inner peripheral surface of the support hole 14a, and the forward side of the piston 15 in the first ring groove 31 (right side in FIG. 1). A second ring groove 32 continuous in the circumferential direction is formed on the wall surface.

  A movable element 33 is inserted into the first ring groove 31 so as to be movable relative to the piston 15. The mover 33 has a ring shape, and a low elastic member 34 is attached to the front wall surface 33 a on the forward side of the piston 15 so as to be inserted into the second ring groove 32. Further, the mover 33 has a first notch 33d formed at the corner between the rear wall 33b of the piston 15 on the backward side (left side in FIG. 1) and the inner wall 33c facing the piston 15. The highly elastic member 35 is attached to the first notch 33d. The movable element 33 has a second notch 33e formed on the back side of the highly elastic member 35 in the first notch 33d.

  In this case, the high elastic member 35 has a higher elastic force than the low elastic member 34, and is disposed so as to be in close contact with the outer peripheral surface of the piston 15. The highly elastic member 35 has an opening 35a that opens to the retreat side of the piston 15, and is configured by a cup-type seal member that can be turned and deformed by frictional resistance with the piston 15 when the piston 15 moves forward. .

  Then, in a state where the hydraulic fluid is not supplied to the hydraulic chamber 29 of the cylinder mechanism 16, the mover 33 has a predetermined clearance between the front wall surface 33 a and the front wall surface 31 a of the first ring groove 31 due to the elastic force of the low elastic member 34. The rear wall surface 33b has a predetermined gap with the rear wall surface 31b of the first ring groove 31.

  In this embodiment, the regulation mechanism of the present invention prohibits relative movement between the piston 15 and the high elastic member 35 when the low elastic member 34 is elastically deformed by the advance of the piston 15, and the high elastic member by the advance of the piston 15. At the time of elastic deformation of 35, relative movement between the piston 15 and the low elastic member 34 is permitted, and the movable element 33 and the high elastic member 35 are configured.

  Therefore, when the hydraulic fluid is supplied to the hydraulic chamber 29 and pressurized, the piston 15 moves forward in the direction of the arrow. At this time, when the applied pressure is low, when the piston 15 moves forward in the seal ring 28, the high elastic member 35 is in close contact with the piston 15, so that the frictional force moves the high elastic member 35 through the high elastic member 35. The child 33 moves forward and elastically deforms so that the low elastic member 34 is compressed by the movable member 33 as shown in FIG. In this case, the low elastic member 34 is elastically deformed, but the high elastic member 35 is not elastically deformed, and the elastic deformation amount (compression amount) of the low elastic member 34 becomes the initial return amount of the piston 15. When the hydraulic fluid is discharged from the hydraulic pressure chamber 29 and is depressurized, the piston 15 is returned to a predetermined position (position shown in FIG. 1) by the restoring force of the elastically deformed low elastic member 34.

  On the other hand, when the applied pressure is high, when the piston 15 moves forward in the seal ring 28, the high elastic member 35 is in close contact with the piston 15, so that the frictional force causes the mover to move through the high elastic member 35. 33 moves forward and elastically deforms so that the low elastic member 34 is compressed by the mover 33 as shown in FIG. Subsequently, when the front wall surface 33a of the mover 33 comes into contact with the front wall surface 31a of the first ring groove 31, the mover 33 and the low elastic member 34 cannot advance. Therefore, when the piston 15 further moves forward, the high elastic member 35 is in close contact with the piston 15, so that the high elastic member 35 opens the opening 35a by its frictional force and the back surface portion is in the second notch 33e. Elastically deforms so that it enters.

  In this case, the low elastic member 34 and the high elastic member 35 are elastically deformed, and the elastic deformation amounts of the low elastic member 34 and the high elastic member 35 become the initial return amount of the piston 15. When the hydraulic fluid is discharged from the hydraulic pressure chamber 29 and is depressurized, first, the piston 15 is returned by the restoring force of the elastically deformed high elastic member 35, and then the elastically deformed low elastic member 34 is restored. The piston 15 is returned to a predetermined position (position shown in FIG. 1) by the force.

  Further, the high elastic member 35 is in close contact with the piston 15 by a high elastic force. When the piston 15 moves by the elastic force (frictional force), the high elastic member 35 moves as a unit, and the relative relationship between the two. Movement is prohibited. When the applied pressure is low, only the low elastic member 34 is elastically deformed and the high elastic member 35 is not elastically deformed. Therefore, the elastic force (frictional force) of the high elastic member 35 with respect to the piston 15, that is, the tightness of the piston. The power does not change. On the other hand, when the applied pressure is high, the high elastic member 35 is elastically deformed in addition to the low elastic member 34, so that the elastic force (frictional force) of the high elastic member 35 with respect to the piston 15, that is, the tightening force of the piston 15 is increased. growing. Therefore, the relative movement of the highly elastic member 35 with respect to the piston 15 is reliably prevented.

  Here, the stroke amount of the piston with respect to the brake fluid pressure will be described. As shown in FIG. 4, when the advance amount of the piston 15 (solid line in FIG. 4) increases with an increase in the brake fluid pressure, the return amount of the piston 15 by the seal ring (FIG. 4) in the conventional disc brake device. (Dotted line) increases at the initial stage and exceeds the advance amount (solid line in FIG. 4), but since the relative movement of the seal ring and the piston 15 occurs, the advance amount does not increase thereafter (solid line in FIG. 4). Will fall below. On the other hand, in the disc brake device of the present embodiment, the return amount of the piston 15 by the seal ring 28 (the dashed line in FIG. 4) continuously increases from the initial time, and the advance amount (solid line in FIG. 4) is increased in the entire region. It will exceed.

  As described above, in the disc brake device of the first embodiment, the piston 15 is movably supported by the cylinder portion 21 of the caliper 14, and when the pressure is applied, the piston 15 moves forward so that the friction pads 12, 13 are moved to the disc rotor 11. The piston 15 can be pulled back to the initial position by a seal ring (return mechanism) 28 provided in the cylinder portion 21 at the time of pressure removal, and the seal ring 28 is moved to the movable element 33, the low elastic member 34, and the high elasticity. A restricting mechanism that restricts relative movement between the piston 15 and the seal ring 28 is provided.

  Therefore, at the time of pressurization of the hydraulic chamber 29, when the piston 15 moves forward, the mover 33 moves forward by the frictional force with the high elastic member 35, and elastically deforms so that the low elastic member 34 is compressed. The high elastic member 35 is elastically deformed, and when the hydraulic chamber 29 is depressurized, the piston 15 is returned to a predetermined position by the restoring force of the elastically deformed low elastic member 34 and the high elastic member 35. Therefore, the piston 15 is restricted in relative movement with the seal ring 28, that is, the high elastic member 35, so that the low elastic member 34 and the high elastic member 35 are elastically deformed alternately. 34 and the elastic deformation of the highly elastic member 35 are alternately released, the return amount of the piston 15 can be ensured appropriately, and the occurrence of the drag phenomenon of the friction pads 12 and 13 can be suppressed.

  Further, in the disc brake device of the first embodiment, when the low elastic member 34 is elastically deformed by the advance of the piston 15, the relative movement of the piston 15 and the high elastic member 35 is prohibited, and the high elastic member 35 of the piston 15 is advanced. At the time of elastic deformation, relative movement between the piston 15 and the low elastic member 34 is permitted. Therefore, relative movement between the piston 15 and the highly elastic member 35 is always prohibited, and an appropriate return amount of the piston 15 can be ensured.

  In the disc brake device of the first embodiment, the return mechanism is accommodated in ring grooves 31 and 32 formed on the inner peripheral surface of the cylinder portion 21 so as to face the outer peripheral surface of the piston 15. A mover 33 that is inserted so as to be movable relative to the piston 15, a low-elasticity member 34 that is inserted into the second ring groove 32 and is mounted on the advance side of the piston 15 in the mover 33, and the piston 15 in the mover 33 A highly elastic member 35 that is attached to the backward side and is in close contact with the piston 15 is provided. Accordingly, the low elastic member 34 can be reliably elastically deformed by the movable element 33 and the high elastic member 35 can be kept in close contact with the piston 15 at all times.

  In the disc brake device according to the first embodiment, a cup-type seal member that can be deformed by turning when the piston 15 moves forward is provided as the highly elastic member 35. Therefore, the highly elastic member 35 as a cup-type seal member can be always brought into close contact with the piston 15 and, at the time of elastic deformation, the tightening force of the highly elastic member 35 can be increased and firmly attached to the piston 15.

  6 is a cross-sectional view illustrating a piston return mechanism in a disc brake device according to a second embodiment of the present invention, and FIGS. 7 and 8 are cross-sectional views illustrating operations of the piston return mechanism of the first embodiment. In addition, the same code | symbol is attached | subjected to the member which has the same function as what was demonstrated in the Example mentioned above, and the overlapping description is abbreviate | omitted.

  In the disc brake device according to the second embodiment, the seal ring 40 functions as a return mechanism that pulls back the piston 15 when the pressure is released, and includes a low-elasticity member and a high-elasticity member. A restricting mechanism for restricting the relative movement is provided.

  That is, as shown in FIG. 6, the outer peripheral surface 15 a of the piston 15 is movably supported with a predetermined gap in the support hole 14 a formed in the cylinder portion of the caliper 14. A first ring groove 41 that is continuous in the circumferential direction is formed on the inner peripheral surface of the support hole 14a, and the forward side of the piston 15 in the first ring groove 41 (right side in FIG. 6). A second ring groove 42 continuous in the circumferential direction is formed on the wall surface.

  A low elastic member 43 is mounted in the second ring groove 42, and a high elastic member 44 is mounted in the first ring groove 41. The high elastic member 44 has a base end portion 44a that is in contact with the bottom portion of the first ring groove 41, a front surface portion 44b that is in close contact with the low elastic member 43 and that faces the front wall surface 41a of the first ring groove 41, while a distal end portion. 44 c extends toward the rear wall 41 b of the first ring groove 41 and is in close contact with the outer peripheral surface 15 a of the piston 15.

  In this case, the high-elasticity member 44 has a higher elastic force than the low-elasticity member 43, and the distal end portion 44 c has a curved shape along the outer peripheral surface 15 a of the piston 15, and is disposed so as to be in close contact. ing. The highly elastic member 44 is configured as a seal member that can be compressed and deformed when the piston 15 moves forward.

  Then, in a state where the hydraulic fluid is not supplied to the hydraulic chamber 29 of the cylinder mechanism, the high elastic member 44 has a front surface 44b and a predetermined clearance from the front wall surface 41a of the first ring groove 41 by the elastic force of the low elastic member 43. have.

  In this embodiment, the restriction mechanism of the present invention prohibits relative movement between the piston 15 and the high elastic member 44 when the low elastic member 43 is elastically deformed by the advance of the piston 15, and the high elastic member by the advance of the piston 15. At the time of elastic deformation of 44, relative movement between the piston 15 and the low elastic member 43 is permitted, and the high elastic member 44 is configured.

  Therefore, when the hydraulic fluid is supplied to the hydraulic chamber 29 and pressurized, the piston 15 moves forward in the direction of the arrow. At this time, when the pressure is low, when the piston 15 advances in the seal ring 40, the high elastic member 44 is in close contact with the piston 15. As shown in FIG. 7, the high elastic member 44 is elastically deformed so that the low elastic member 43 is compressed. In this case, the low elastic member 43 is elastically deformed, but the high elastic member 44 is not elastically deformed, and the elastic deformation amount (compression amount) of the low elastic member 43 becomes the initial return amount of the piston 15. When the hydraulic fluid is discharged from the hydraulic pressure chamber 29 and is depressurized, the piston 15 is returned to a predetermined position (position shown in FIG. 6) by the restoring force of the elastically deformed low elastic member 43.

  On the other hand, when the pressure is high, when the piston 15 advances in the seal ring 40, the high elastic member 44 is in close contact with the piston 15, and therefore the high elastic member 44 advances due to the frictional force. As shown in FIG. 8, the high elastic member 44 is elastically deformed so that the low elastic member 43 is compressed. Subsequently, when the front surface portion 44b of the high elastic member 44 contacts the front wall surface 41a of the first ring groove 41, the high elastic member 44 and the low elastic member 43 cannot advance. Therefore, when the piston 15 further advances, since the high elastic member 44 is in close contact with the piston 15, the high elastic member 44 is elastically deformed so as to be compressed by the frictional force.

  In this case, the low elastic member 43 and the high elastic member 44 are elastically deformed, and the elastic deformation amounts of the low elastic member 43 and the high elastic member 44 become the initial return amount of the piston 15. When the hydraulic fluid is discharged from the hydraulic chamber 29 and is depressurized, the piston 15 is first returned by the restoring force of the elastically deformed high elastic member 44, and then the elastically deformed low elastic member 43 is restored. The piston 15 is returned to a predetermined position (position shown in FIG. 6) by the force.

  Further, the high elastic member 44 is in close contact with the piston 15 with a high elastic force, and when the piston 15 moves due to the elastic force (frictional force), the high elastic member 44 moves together, and the relative Movement is prohibited. When the applied pressure is low, only the low elastic member 43 is elastically deformed and the high elastic member 44 is not elastically deformed. Therefore, the elastic force (frictional force) of the high elastic member 44 against the piston 15, that is, the tightness of the piston. The power does not change. On the other hand, when the applied pressure is high, the high elastic member 44 is elastically deformed in addition to the low elastic member 43, so that the elastic force (friction force) of the high elastic member 44 against the piston 15, that is, the tightening force of the piston 15 is increased. growing. That is, since the highly elastic member 44 has a curved shape that forms a wedge with respect to the forward movement of the piston 15, the full length is compressed and the tightening force is increased. Therefore, the relative movement of the highly elastic member 44 with respect to the piston 15 is reliably prevented.

  As described above, in the disc brake device of the second embodiment, the piston 15 is movably supported by the cylinder portion 21 of the caliper 14, and when the pressure is applied, the piston 15 moves forward so that the friction pads 12, 13 are moved to the disc rotor 11. And the piston 15 can be pulled back to the initial position by a seal ring (return mechanism) 40 provided in the cylinder portion 21 when the pressure is removed. The seal ring 40 is made up of the low elastic member 43 and the high elastic member 44. A restricting mechanism for restricting relative movement between the piston 15 and the seal ring 40 is provided.

  Therefore, when the hydraulic pressure chamber 29 is pressurized, when the piston 15 moves forward, the high elastic member 44 moves forward by frictional force and elastically deforms so that the low elastic member 43 is compressed. When the hydraulic chamber 29 is depressurized, the piston 15 is returned to a predetermined position by the restoring force of the elastically deformed low elastic member 43 and high elastic member 44. Therefore, the piston 15 is restricted in relative movement with the seal ring 40, that is, the high elastic member 44, so that the low elastic member 43 and the high elastic member 44 are elastically deformed alternately, and at the time of decompression, the low elastic member The elastic deformation of 43 and the highly elastic member 44 is alternately released, the return amount of the piston 15 can be ensured appropriately, and the occurrence of the drag phenomenon of the friction pads 12 and 13 can be suppressed.

  In the disc brake device of the second embodiment, the return mechanism is accommodated in ring grooves 41 and 42 formed on the inner peripheral surface of the cylinder portion 21 so as to face the outer peripheral surface of the piston 15. A high-elasticity member 44 that is inserted so as to be movable relative to the piston 15 and that extends to the backward side of the piston 15 so that the tip 44c is in close contact with the piston 15, and a piston in the high-elasticity member 44 that is inserted into the second ring groove 42. 15 and a low elastic member 43 to be mounted on the forward side. Therefore, the low elastic member 43 can be reliably elastically deformed by the high elastic member 44 and the high elastic member 44 can be kept in close contact with the piston 15 at all times.

  In the disc brake device of the second embodiment, a seal member that can be compressed and deformed when the piston 15 moves forward is provided as the highly elastic member 44. Therefore, the highly elastic member 44 as a seal member that can be compressed and deformed can always be brought into close contact with the piston 15, and at the time of elastic deformation, the tightening force of the highly elastic member 44 can be increased and firmly brought into close contact with the piston 15. it can.

  As described above, the disc brake device according to the present invention is provided with the restriction mechanism that restricts the relative movement between the piston and the return mechanism, thereby suppressing the relative movement between the piston and the return mechanism and generating the pad drag phenomenon. Can be suppressed, and is suitable for any disc brake device.

It is sectional drawing showing the piston return mechanism in the disc brake apparatus which concerns on Example 1 of this invention. It is sectional drawing showing the action | operation of the piston return mechanism of Example 1. FIG. It is sectional drawing showing the action | operation of the piston return mechanism of Example 1. FIG. It is a graph showing the piston stroke amount with respect to piston hydraulic pressure. It is sectional drawing showing the disc brake apparatus of Example 1. FIG. It is sectional drawing showing the piston return mechanism in the disc brake apparatus which concerns on Example 2 of this invention. It is sectional drawing showing the action | operation of the piston return mechanism of Example 2. FIG. It is sectional drawing showing the action | operation of the piston return mechanism of Example 2. FIG.

Explanation of symbols

11 Disc rotor 12 Inner pad (friction pad)
13 Outer pad (friction pad)
14 Caliper 15 Piston 16 Cylinder mechanism 21 Cylinder part 24, 25 Friction material 28, 40 Seal ring (return mechanism)
29 Hydraulic chambers 31, 41 First ring groove 32, 42 Second ring groove 33 Movable element (regulation mechanism)
34, 43 Low elastic member 35, 44 High elastic member (regulation mechanism, cup-type seal member)

Claims (6)

A disk rotor that rotates about a rotation axis;
A friction pad facing the friction surface of the disk rotor;
A cylinder for supporting the friction pad on the friction surface of the disk rotor so as to be close to and away from the friction surface;
A piston capable of advancing at the time of pressurization and pressing the friction pad against the disk rotor;
A return mechanism that has a low-elasticity member and a high-elasticity member and pulls back the piston when pressure is removed;
A restriction mechanism for restricting relative movement between the piston and the return mechanism;
A disc brake device comprising:   The restricting mechanism prohibits relative movement between the piston and the high elastic member when the low elastic member is elastically deformed by the advance of the piston, and the piston and the piston when the high elastic member is elastically deformed by the advance of the piston. 2. The disc brake device according to claim 1, wherein relative movement with the low elastic member is permitted.   The return mechanism is accommodated in a ring groove formed on the inner peripheral surface of the cylinder so as to face the outer peripheral surface of the piston, and a movable element inserted into the ring groove so as to be movable relative to the piston, and the movable member The low-elasticity member mounted on the advance side of the piston in the child and the high-elasticity member attached on the retreating side of the piston in the mover and in close contact with the piston. Or the disc brake device of 2.   The disc brake device according to claim 3, wherein the highly elastic member is a cup-type seal member that can be deformed by turning when the piston moves forward.   The return mechanism is accommodated in a ring groove formed on the inner peripheral surface of the cylinder so as to face the outer peripheral surface of the piston, and is inserted into the ring groove so as to be relatively movable with respect to the piston. The high-elastic member that extends to the piston and has a tip portion that is in close contact with the piston, and the low-elastic member that is inserted into the ring groove and is mounted on the advance side of the piston in the high-elasticity member. The disc brake device according to claim 1 or 2.   6. The disc brake device according to claim 5, wherein the highly elastic member is a seal member that can be compressed and deformed when the piston moves forward.

Images