JP7161931B2 - disc brake - Google Patents

Description

The present invention relates to disc brakes used for braking vehicles.

Disc brakes with electric parking brakes are known as braking devices for vehicles. For example, the disc brake described in Patent Document 1 includes a piston propulsion mechanism that converts the rotational motion of a motor gear unit into linear motion to propel a piston and hold the propelled piston at a braking position. This piston propulsion mechanism includes a spindle rod to which rotation from an electric motor is transmitted, an adjuster nut threadedly engaged with the spindle rod, a ring shaft supported on the bottom surface of the cylinder so as not to rotate relative to each other, and an adjuster nut. a plurality of planetary rods disposed between the ring shaft.

Therefore, a base plate is integrally connected to the ring shaft, and an engaging concave portion is formed on the outer peripheral surface of the base plate. On the other hand, a pin member is press-fitted and fixed to the radially outer end portion of the bottom surface of the cylinder so as to protrude into the cylinder. The pin member protruding from the bottom surface of the cylinder is engaged with the engagement recess of the base plate, thereby supporting the base plate and thus the ring shaft so as not to rotate relative to the bottom surface of the cylinder.

WO2018/003393 pamphlet

In the piston propulsion mechanism described in Patent Document 1 mentioned above, since the pin member is press-fitted into the radially outer end portion of the bottom surface of the cylinder, the work in the press-fitting process is extremely complicated, which poses a problem in mass production. It's becoming Moreover, a pin member is required as a separate part, which is also a problem from the viewpoint of the number of parts.

Another object of the present invention is to provide a disc brake that can be mass-produced by simplifying the assembly process.

A first disc brake according to the present invention includes a pair of pads arranged on both sides of the rotor in the axial direction across the rotor, a piston for pressing one of the pair of pads against the rotor, and the piston A caliper body having a cylinder slidably fitted thereon, a motor provided in the caliper body, and a rotary/linear motion provided in the caliper body that converts the rotary motion of the motor into linear motion to propel the piston. a conversion mechanism, wherein the rotation-to-linear motion conversion mechanism comprises a tubular member having a projection projecting from one end surface in the axial direction; a shaft member for transmission , wherein a base plate positioned inside the cylinder is disposed on the inner peripheral side of one end along the axial direction of the cylindrical member, and the protrusion is closer to the rotor than the base plate. is projected to the opposite side, and the cylinder is formed with an engagement recess portion in the bottom surface of the cylinder with which the projection portion of the tubular member is engaged.

A second disc brake according to the present invention includes a pair of pads arranged on both sides of the rotor in the axial direction across the rotor, a piston for pressing one of the pair of pads against the rotor, and the A caliper body having a cylinder in which a piston is protrusively arranged, a motor provided in the caliper body, and a piston propulsion mechanism provided in the cylinder for propelling the piston, wherein the piston propulsion mechanism comprises: It has an input member that extends axially in the cylinder, has a threaded portion formed on its outer peripheral surface, and receives rotation from the motor, and an engaging threaded portion that meshes with the threaded portion of the input member. a tubular rotary linear motion member that is moved in the axial direction of the cylinder by rotation of the input member to transmit torque from the motor to the piston; A cylindrical support member having a protrusion protruding from one end face of the direction, and a cylindrical support member and the rotary linear motion member are arranged so as to be engaged with both, and are rotated by the rotation of the input member. a rolling element that, when the rotary linear motion member rotates, imparts a rotational resistance to the rotary linear motion member to cause the rotary linear motion member to linearly move while rotating relative to the input member ; A base plate positioned inside the cylinder is disposed on the inner peripheral side of one end along the axial direction of the member, the projection protrudes from the base plate to the side opposite to the rotor side, and the cylinder includes: It is characterized in that an engagement recess is formed on the bottom surface thereof with which the protrusion of the support member engages.

According to the present invention, the assembly process can be simplified, and mass production can be accommodated.

It is a sectional view of a disc brake concerning this embodiment. FIG. 2 is an enlarged view of a main portion of FIG. 1; FIG. 2 is an exploded perspective view of a piston propulsion mechanism in the disc brake of FIG. 1; FIG. 2 is an enlarged cross-sectional view of a roller holding unit employed in the disc brake of FIG. 1;

A disk brake 1 according to this embodiment will be described below with reference to FIGS. 1 to 4. FIG. In the following description, for convenience of explanation, the right side in FIGS. 1, 2 and 4 is defined as one end side of the disc brake 1, and the left side in FIGS. . 1, 2 and 4 is defined as the axial direction of the disc brake 1. As shown in FIG.

As shown in FIG. 1, disc brakes 1 according to the present embodiment are arranged on both axial sides of a disc rotor D (rotor) attached to a rotating portion (not shown) of a vehicle. A pair of inner and outer brake pads 2, 3 and a floating caliper 4 are provided. A pair of inner and outer brake pads 2, 3 and a floating caliper 4 are axially movably supported by a carrier 5 fixed to a non-rotating part (not shown) such as a knuckle of the vehicle.

A caliper body 6, which is the main body of the caliper 4, includes a cylinder portion 7 formed on the base end side (one end side), and extending from the cylinder portion 7 to the other end side so as to straddle the disk rotor D, and extending to the other end side (other end side). and a claw portion 8 formed on the end side). A cylinder 10 in which a piston 18 is axially slidably fitted is formed in the cylinder portion 7 . The cylinder 10 has a large-diameter opening 10A whose other end is open, and a bottomed small-diameter opening 10B whose one end is closed by a bottom 13 having a shaft hole 12 . The bottom surface of the cylinder 10 is formed with an engagement recess 15 with which a stopper protrusion 160 provided on a nut member 77, which will be described later, is engaged. The engagement recesses 15 are formed corresponding to the stopper projections 160, and in this embodiment, two engagement recesses 15 are formed at a pitch of 180°. These engaging recesses 15, 15 are formed in a substantially rectangular shape in plan view. These engaging recesses 15 , 15 are formed on the bottom surface of the cylinder 10 at the outermost end in the radial direction. In other words, a part of the inner surface of the engaging recess 15 continues from the inner peripheral surface of the small-diameter opening 10B. These engaging recesses 15 are formed by cores placed in the casting mold. An annular groove 14 is formed in the inner wall surface on the other end side of the large-diameter opening 10A of the cylinder 10 . A piston seal 16 is provided in the annular groove 14 .

The piston 18 is shaped like a cup consisting of a bottom portion 19 and a cylindrical portion 20 . The piston 18 is arranged so that the bottom portion 19 faces the inner brake pad 2 . The piston 18 is axially slidably fitted in the large-diameter opening 10A of the cylinder 10 . The outer peripheral surface of the cylindrical portion 20 of the piston 18 contacts the piston seal 16 . A hydraulic chamber 21 defined by the piston seal 16 is formed between the piston 18 and the bottom 13 of the cylinder 10 . Hydraulic pressure is supplied to the hydraulic pressure chamber 21 from a hydraulic pressure source (not shown) such as a master cylinder or a hydraulic pressure control unit through a port (not shown) provided in the cylinder portion 7 .

A recess 25 is formed in the outer peripheral edge of the bottom 19 of the piston 18 . A convex portion 26 formed on the back surface of the inner brake pad 2 is engaged with the concave portion 25 . As a result, the piston 18 becomes non-rotatable relative to the cylinder 10 and, by extension, the caliper body 6 . A dust boot 27 is provided between the bottom 19 of the piston 18 and the large diameter opening 10A of the cylinder 10 . A circular concave portion 30 and an annular inclined portion 31 that is continuous with the circular concave portion 30 and whose diameter increases toward the one end side are formed on the inner surface of the bottom portion 19 of the piston 18 on the one end side.

The caliper body 6 is provided with a motor gear unit 36 containing an electric motor 35 and a speed reduction mechanism, and a piston propulsion mechanism 37 as a rotation/linear motion converting mechanism. The piston propulsion mechanism 37 converts the rotational motion (output) of the motor gear unit 36 into linear motion to propel the piston 18 (moves it to the other end) and holds the piston 18 at the braking position. . An electronic control unit 38 that controls the electric motor 35 is connected to the motor gear unit 36 . A parking switch 39 is connected to the electronic control unit 38 to be operated when the parking brake is turned ON/OFF. It should be noted that the electronic control unit 38 can operate the parking brake based on a signal from the vehicle side without operating the parking switch 39 . Also, the reduction mechanism of the motor gear unit 36 includes, for example, a spur-tooth multistage reduction mechanism and a planetary gear reduction mechanism.

2 and 3, the piston driving mechanism 37 includes a spindle 48 as an input member, a sliding screw engaging portion 45, and a roller screw mechanism 46. As shown in FIG. The spindle 48 includes a shaft portion 49 formed on one end side, a male thread portion 50 formed on the other end side, and a flange portion 51 formed between the shaft portion 49 and the male thread portion 50. . One end of the shaft portion 49 of the spindle 48 is formed with a polygonal shaft portion 53 (see FIG. 3) integrally connected to an output member of the motor gear unit 36 (for example, a carrier of a planetary reduction gear mechanism, etc.). . In this embodiment, the polygonal shaft portion 53 is formed into a hexagonal shaft portion. Rotational torque from the motor gear unit 36 is thereby transmitted to the spindle 48 . For the connection between the shaft portion 49 of the spindle 48 and the output member of the motor gear unit 36, a mechanical element capable of transmitting rotational torque, such as a spline, a key, etc., may be used in addition to the rotation stop by the polygonal shaft portion 53. can. The male threaded portion 50 of the spindle 48 is positioned at its other end adjacent a circular recess 30 provided in the bottom 19 of the piston 18 . A rolling surface 54 (see FIG. 3) of the thrust ball 65 is formed on one end surface of the flange portion 51 of the spindle 48 . A plurality of protrusions 55 are formed along the circumferential direction on the other end surface of the flange portion 51 of the spindle 48 .

A guide sleeve 56 is fitted to the inner peripheral surface of the shaft hole 12 formed in the bottom portion 13 of the cylinder 10 . A shaft portion 49 of the spindle 48 is rotatably supported by the caliper body 6 via the guide sleeve 56 . A seal ring 57 seals between the shaft hole 12 of the cylinder 10 and the shaft portion 49 of the spindle 48 . The seal ring 57 is arranged on the other end side of the guide sleeve 56 .

A base plate 60 is positioned within the cylinder 10 near its bottom 13 . The base plate 60 is arranged on the inner peripheral side of one end of a nut member 77 which will be described later. Specifically, the base plate 60 is arranged on the inner peripheral side of one end of the large-diameter nut portion 151 of the nut member 77 so as to face the one end side (rolling surface 54 ) of the flange portion 51 of the spindle 48 . The base plate 60 is formed in a disc shape having a shaft hole 61 . The shaft portion 49 of the spindle 48 is slidably fitted into the shaft hole 61 . A rolling surface 63 for a thrust ball 65 is formed on the other end surface of the base plate 60 . A plurality of thrust balls 65 are rotatably arranged between a rolling surface 54 provided on one end surface of the flange portion 51 of the spindle 48 and a rolling surface 63 provided on the other end surface of the base plate 60 . A plurality of thrust balls 65 are held by retainers 66 at regular intervals in the circumferential direction.

The outer peripheral surface of the base plate 60 is formed with an inclined surface 68 whose diameter is reduced toward one end. A C-shaped (arcuate) retaining ring 70 is mounted between a retaining groove portion 158 of a nut member 77 and an inclined surface 68 of the base plate 60 , and the base plate 60 moves toward one end with respect to the nut member 77 . regulate not to. The retaining ring 70 is a retaining ring for a hole having a circular cross section, and is fitted in the retaining groove 158 of the nut member 77 in a compressed (reduced diameter) state. A plurality of cutouts 71 (see FIG. 3) are formed on the outer peripheral surface of the base plate 60 for axially circulating the brake fluid.

The sliding screw engaging portion 45 is configured by a threaded portion between the male threaded portion 50 of the spindle 48 and the female threaded portion 84 of the shaft member 75 to be described later. The slide screw engaging portion 45 is configured to be able to move the shaft member 75 in the rotational direction and the axial direction when the spindle 48 is rotated in the apply direction or the release direction. The slip screw engaging portion 45 has a reverse efficiency set to 0 or less, and the axial thrust acting on the shaft member 75 cannot rotate the spindle 48 . That is, the sliding screw engaging portion 45 can convert the rotational torque of the spindle 48 into axial thrust force on the shaft member 75 , but the axial thrust force of the shaft member 75 is converted into the rotational torque of the spindle 48 . cannot be converted to

The roller screw mechanism 46 includes a shaft member 75 as a shaft member or a rotary linear motion member, a planetary roller 76 as a rolling element, and a nut member 77 as a tubular member or a support member. A shaft member 75 is arranged around the spindle 48 . The shaft member 75 is formed cylindrical. The shaft member 75 is configured by integrally connecting a small-diameter shaft portion 79 formed on one end side and a large-diameter shaft portion 80 formed on the other end side. A plurality of projections 81 (see FIG. 3) are formed on one end face of the small-diameter shaft portion 79 at intervals in the circumferential direction. Annular grooves 83 are formed at a predetermined pitch along the axial direction on the outer peripheral surface of the one end side of the small-diameter shaft portion 79 . Each annular groove portion 83 is engaged with each annular peak portion 110 provided on the outer peripheral surface of each planetary roller 76 .

A female threaded portion 84 is formed as an engaging threaded portion on the inner peripheral surface of the small-diameter shaft portion 79 . The male threaded portion 50 of the spindle 48 is screwed into the female threaded portion 84 to act as the slide screw engaging portion 45 . A communication hole 86 is formed through the peripheral wall portion of the large-diameter shaft portion 80 along the radial direction. A rolling surface 88 for the thrust ball 99 is formed on the other end surface of the large-diameter shaft portion 80 . A holder fitting hole 89 having a diameter larger than that of the female threaded portion 84 and into which a bearing holder 103 (to be described later) is fitted is formed on the other end side of the shaft hole of the large-diameter shaft portion 80 . When the plurality of projections 81 provided on one end face of the small-diameter shaft portion 79 of the shaft member 75 and the plurality of projections 55 provided on the other end face of the flange portion 51 of the spindle 48 interfere with each other, relative rotation between the two is regulated. This prevents the spindle 48 (male threaded portion 50) from sticking (biting) due to excessive screwing into the shaft member 75 (female threaded portion 84).

A thrust plate 92 is arranged to face the other end face of the shaft member 75 (large-diameter shaft portion 80). The thrust plate 92 is formed in an annular shape having a shaft hole 93 through which the male threaded portion 50 of the spindle 48 is inserted. The inner diameter of the shaft hole 93 of the thrust plate 92 substantially matches the inner diameter of the holder fitting hole 89 of the large-diameter shaft portion 80 . A plurality of cutouts 95 (see FIG. 3) are formed on the outer peripheral surface of the thrust plate 92 for axially circulating the brake fluid. A contact surface 94 is formed on the other end surface of the thrust plate 92 to contact the inclined portion 31 provided on the bottom portion 19 of the piston 18 . A rolling surface 97 for a thrust ball 99 is formed on one end surface of the thrust plate 92 . A plurality of thrust balls 99 are rotatably arranged between the rolling surface 97 of the thrust plate 92 and the rolling surface 88 of the shaft member 75 (large-diameter shaft portion 80). A plurality of thrust balls 99 are held by a retainer 100 at regular intervals in the circumferential direction.

A bearing holder 103 is inserted from the inner peripheral surface of the shaft hole 93 of the thrust plate 92 to the inside of the holder fitting hole 89 of the large-diameter shaft portion 80 . The bearing holder 103 is formed in a cylindrical shape. An annular locking portion 105 projecting radially outward is formed on the outer peripheral surface of the other end of the bearing holder 103 . The bearing holder 103 has two elastic pieces 106 provided on its outer peripheral surface at a pitch of 180°. Each elastic piece 106 is formed by cutting the outer peripheral wall of the bearing holder 103 . A locking claw portion 107 is provided at the tip of each elastic piece 106 so as to protrude radially outward. The locking claw portion 107 can be projected and retracted from the outer peripheral surface of the bearing holder 103 along the radial direction by elastically deforming the elastic piece 106 . The annular locking portion 105 of the bearing holder 103 abuts against the other end surface of the thrust plate 92, and the locking claw portions 107 of the elastic pieces 106 are inserted into the communicating holes 86 of the large-diameter shaft portion 80 from the inside. The engagement allows the thrust plate 92 to be integrally retained on the other end of the shaft member 75 with the thrust ball 99 including the retainer 100 .

A plurality of planetary rollers 76 are engaged with the outer periphery of the small-diameter shaft portion 79 of the shaft member 75 at intervals along the circumferential direction. In this embodiment, six planetary rollers 76 are arranged. Annular peaks 110 are formed on the outer peripheral surface of the planetary roller 76 at a predetermined pitch along the axial direction. Each annular peak portion 110 of the planetary roller 76 is engaged with each annular groove portion 83 provided on the outer peripheral surface of the shaft member 75 (small-diameter shaft portion 79). As a result, relative axial movement between the shaft member 75 and the planetary rollers 76 is restricted. These planetary rollers 76 are held by a roller holding unit 120 .

As shown in FIGS. 2 to 4, the roller holding unit 120 has the function of holding each planetary roller 76 so that the adjacent planetary rollers 76 do not interfere with each other, and the one end side and the other side of each planetary roller 76 . and a function as a pressurizing mechanism that applies an axial load (contact pressure, frictional force) toward the end. The roller holding unit 120 integrally holds a plurality of planetary rollers 76 engaged with the outer peripheral surface of the shaft member 75 in a roller cage 124 together with a collar member 122 and a compression coil spring 123 . The roller holding unit 120 is supported around the shaft member 75 so as to be rotatable relative to the shaft member 75 and axially slidable relative to a nut member 77 which will be described later. Roller cage 124 is formed in a cylindrical shape. A peripheral wall portion of the roller cage 124 is formed with first and second roller housing holes 127 and 128 that respectively house the planetary rollers 76 . In this embodiment, three first roller housing holes 127 and three second roller housing holes 128 are formed.

The first and second roller receiving holes 127, 128 are alternately formed along the circumferential direction. The first and second roller receiving holes 127 and 128 are formed in a substantially rectangular shape elongated in the axial direction. As can be seen from FIG. 4, when the planetary rollers 76 are respectively accommodated in the first and second roller accommodating holes 127 and 128, a circular shape connecting the peripheral wall portion of the roller cage 124 and the radial center of each planetary roller 76 is formed. are arranged so as to substantially coincide with each other. As a result, the rolling of the roller cage 124 into the engaging portion between the planetary rollers 76 and the shaft member 75 and the engaging portion between the planetary rollers 76 and the nut member 77 is suppressed. Position can be held.

As can be seen from FIG. 4, the opening positions of the first and second roller housing holes 127 and 128 are offset from each other along the axial direction. Referring also to FIG. 3, a plurality of spring receiving pieces 130, 130 are formed at the other end of the roller cage 124 at intervals in the circumferential direction. In the other end surface of the roller cage 124, notch grooves 131 having a substantially rectangular shape in a plan view are formed at positions corresponding to the first roller housing holes 127, respectively. A plurality of reinforcing ribs 135, 135 protruding radially inward are formed between the first and second roller receiving holes 127, 128 in the peripheral wall portion of the roller cage 124. As shown in FIG. Further, the roller cage 124 is rotatably supported with respect to the shaft member 75 by the inner wall surfaces of the plurality of reinforcing ribs 135 abutting against the outer peripheral surface of the shaft member 75. , are rotatably supported with respect to the shaft member 75 .

A collar member 122 is arranged on the other end side of the first and second roller housing holes 127 and 128 in the roller cage 124 . Collar member 122 is formed in a cylindrical shape. The outer peripheral surface of the collar member 122 contacts the inner peripheral surface of the roller cage 124 . Referring also to FIG. 3, one end surface of the collar member 122 is formed with engaging recesses 137 that engage with reinforcing ribs 135 provided on the roller cage 124 . A clearance 138 extending in the axial direction is provided at one portion of the peripheral wall portion of the collar member 122 where the engaging recess 137 is formed. A compression coil spring 123 is arranged on the other end side of the collar member 122 . The compression coil spring 123 has its outer peripheral surface in contact with the inner peripheral surface of the roller cage 124 .

The planetary rollers 76 are accommodated in the first and second roller accommodating holes 127 and 128 of the roller cage 124 that constitutes the roller holding unit 120, and the annular peaks 110 of the planetary rollers 76 are attached to the shaft members. 75 engages with each annular groove 83 . Subsequently, the collar member 122 is inserted into the roller cage 124 from the other end side, and the reinforcing ribs 135 of the roller cage 124 are engaged with the engaging recesses 137 of the collar member 122 . As a result, the roller cage 124 and the collar member 122 are connected so as not to rotate relative to each other. Subsequently, the compression coil spring 123 is accommodated in the roller cage 124 from the other end side in a compressed state, and while one end of the compression coil spring 123 is brought into contact with the other end surface of the collar member 122, the roller cage 124 is compressed. Each spring receiving piece 130 is bent radially inward, and each spring receiving piece 130 holds the compression coil spring 123 .

Thus, in this roller holding unit 120, as can be seen from FIG. It abuts on the end face and biases each planetary roller 76 toward one end side. At this time, a clearance is provided between one end surface of the planetary roller 76 accommodated in each second roller accommodation hole 128 and one end surface of each second roller accommodation hole 128 . As a result, the urging force of the compression coil spring 123 pushes the annular ridges 110 of the planetary rollers 76 accommodated in the second roller accommodating holes 128 toward the one end side of the annular grooves 83 of the shaft member 75 . is applied to the engaging portion, an axial load (contact pressure, frictional force) directed toward one end is applied.

On the other hand, in the roller holding unit 120 , the biasing force of the compression coil spring 123 causes one end surface of each first roller housing hole 127 of the roller cage 124 to move one end of each planetary roller 76 housed in each first roller housing hole 127 . It abuts on the end face and biases each planetary roller 76 toward the other end side. At this time, a clearance is provided between the other end surface of the planetary roller 76 accommodated in each first roller accommodation hole 127 and the other end surface of the first roller accommodation hole 127 and one end surface of the collar member 122 . As a result, the urging force of the compression coil spring 123 pushes the annular ridges 110 of the planetary rollers 76 accommodated in the first roller accommodating holes 127 toward the other end of the annular grooves of the shaft member 75 . By pressing against 83, an axial load (contact pressure, frictional force) directed toward the other end is applied to this engaging portion.

In short, the roller holding unit 120 engages the annular ridges 110 of the planetary rollers 76 housed in the second roller housing holes 128 of the roller cage 124 with the annular grooves 83 of the shaft member 75. , a load (contact pressure, frictional force) directed toward one end is applied, while each annular peak portion 110 of each planetary roller 76 housed in each first roller housing hole 127 and the shaft member 75 are in contact with each other. The engaging portion with each annular groove portion 83 functions as a pressurizing mechanism that applies an axial load (contact pressure, frictional force) toward the other end.

Further, as shown in FIGS. 1 and 2, the nut member 77 is formed in a stepped cylindrical shape. The nut member 77 is configured by integrally connecting a large-diameter nut portion 151 arranged on one end side and a small-diameter nut portion 152 arranged on the other end side. Referring also to FIG. 3, from one end surface of the large diameter nut portion 151, a stopper projection portion 160 projects toward the one end side. The stopper protrusions 160, 160 are formed to face each other at a pitch of 180°. Each stopper protrusion 160 is formed to have a substantially rectangular cross section. These stopper protrusions 160, 160 are engaged with engagement recesses 15, 15 provided in the bottom portion 13 of the cylinder 10 of the caliper body 6, respectively. As a result, the nut member 77 is restricted from rotating relative to the caliper body 6 (cylinder portion 7). One end of the large-diameter nut portion 151 is arranged at a position close to the bottom portion 13 of the cylinder 10 . The large-diameter nut portion 151 is provided with a plurality of passages 157 that penetrate the peripheral wall portion in the radial direction and allow the brake fluid to flow. An annular retaining groove portion 158 to which the retaining ring 70 is attached is formed on the inner peripheral surface of the large-diameter nut portion 151 . The other end of the small-diameter nut portion 152 is located slightly on the other end side of the communication hole 86 provided in the shaft member 75 in the axial direction. A female threaded portion 155 is formed on the inner peripheral surface of the small diameter nut portion 152 . The female threaded portion 155 is provided over substantially the entire axial region of the small-diameter nut portion 152 .

The female threaded portion 155 of the nut member 77 is engaged (engaged) with each annular peak portion 110 of each planetary roller 76 . The female screw portion 155 of the nut member 77 and the annular ridge portions 110 of the planetary roller 76 have the same pitch (axial interval) between the female screw portion 155 and the annular ridge portions 110, and the female screw portion 155 has the same pitch. By setting the number of threads to an integral multiple of the number of planetary rollers 76, they are meshed with each other. For example, when six planetary rollers 76 are used and the pitch of the female threaded portion 155 and each annular ridge portion 110 is set to 1 mm, the number of threads of the female threaded portion 155 is set to 6 (6 x 1). , the female threaded portion 155 of the nut member 77 and the annular ridges 110 of the planetary roller 76 can be meshed with each other. Note that the lead at this time is 6 mm.

Next, the action of the disc brake 1 of this embodiment will be described.
When the driver depresses the brake pedal (not shown), the hydraulic pressure corresponding to the force applied to the brake pedal is applied to the caliper body 6 (cylinder 10) via the master cylinder and the hydraulic circuit (not shown). It is supplied to the hydraulic chamber 21 . As a result, the piston 18 moves from its original position (see FIG. 1) during non-braking to the other end side, pressing the inner brake pad 2 against the disc rotor D while elastically deforming the piston seal 16 . Subsequently, the caliper 4 moves to one end side with respect to the carrier 5 by the reaction force of the piston 18, and presses the outer brake pad 3, which is in contact with the claw portion 8, against the disc rotor D. As shown in FIG. As a result, the disk rotor D is sandwiched between the pair of inner and outer brake pads 2 and 3 to generate a frictional force, thereby generating braking force for the vehicle.

On the other hand, when the driver releases the brake pedal, the supply of hydraulic pressure from the master cylinder to the hydraulic pressure chamber 21 is stopped, and the hydraulic pressure in the hydraulic pressure chamber 21 decreases. As a result, the piston 18 is retracted to the original position by the restoring force of the elastic deformation of the piston seal 16, and the braking force of the vehicle is released. If the amount of movement of the piston 18 increases as the inner and outer brake pads 2, 3 wear and the limit of elastic deformation of the piston seal 16 is exceeded, slippage occurs between the piston 18 and the piston seal 16. , the original position of the piston 18 relative to the caliper body 6 is moved by the slippage. Thereby, even when the inner and outer brake pads 2, 3 are worn, the pad clearance is adjusted to be constant.

Next, the action of the parking brake that maintains the stopped state of the vehicle by the disk brake 1 according to this embodiment will be described.
When the electronic control unit 38 receives an apply command (parking brake activation command) by operating the parking switch 39 or the like from the parking brake released state, the electric motor 35 of the motor gear unit 36 is energized to rotate the spindle 48 in the apply direction. Let The rotational torque transmitted to the spindle 48 is transmitted to the shaft member 75 via the slide screw engaging portion 45 between the male threaded portion 50 of the spindle 48 and the female threaded portion 84 of the shaft member 75 . Since the rotation torque transmitted from the spindle 48 is given to the shaft member 75 as a reaction force by the rotation resistance torque from each planetary roller 76, the shaft member 75 rotates relative to the spindle 48. At the same time, an axial thrust is applied to the other end.

The rotational torque transmitted to the shaft member 75 is transmitted to the planetary rollers 76 via the engaging portions between the annular grooves 83 of the shaft member 75 and the annular peaks 110 of the planetary rollers 76 . The rotational torque transmitted to the planetary roller 76 is transmitted to the nut member 77 via the engaging portions (meshing portions) between the annular ridges 110 of the planetary roller 76 and the female threaded portion 155 of the nut member 77 . The nut member 77 is supported so as not to rotate relative to the cylinder portion 7 by engagement between the stopper protrusions 160 and 160 and the accommodation recesses 15 , 15 . It revolves around the axis of the nut member 77 in the apply direction while rotating around the rotation axis. At this time, each planetary roller 76 generates an axial thrust toward the other end in accordance with the transmitted rotational torque. The thrust force generated in each planetary roller 76 is transmitted to the shaft member 75 via the engaging portions between the annular ridges 110 of the planetary rollers 76 and the annular grooves 83 of the shaft member 75 . As a result, the shaft member 75 moves to the other end while rotating.

On the other hand, at the sliding screw engagement portion 45 between the male threaded portion 50 of the spindle 48 and the female threaded portion 84 of the shaft member 75, a rotational torque substantially equal to the rotational torque transmitted from the shaft member 75 to the planetary roller 76 is applied to the spindle 48. to the shaft member 75. Therefore, as described above, an axial thrust toward the other end is generated in the slide screw engaging portion 45 according to the transmission torque. Due to the axial thrust generated in the slide screw engaging portion 45 , the shaft member 75 receives an axial thrust toward the other end of the spindle 48 . In this way, the shaft member 75 is driven by the axial thrust toward the other end due to the rotational torque transmitted from the spindle 48 at the slide screw engaging portion 45 and the force generated by the nut member 77 of the roller screw mechanism 46 and each planetary roller 76 . It receives an axial thrust that is the sum of the axial thrust toward the other end generated between them.

The shaft member 75 that receives the axial thrust toward the other end moves toward the other end while rotating along the female threaded portion 155 of the nut member 77 , and hits the thrust plate 92 via the thrust ball 99 . The contact surface 94 is pressed against the slope 31 of the bottom 19 of the piston 18 . As a result, the piston 18 moves to the other end side and is pressed against the inner brake pad 2 . As a result, the inner and outer brake pads 2, 3 are pressed against the disk rotor D, and the braking force of the vehicle is generated. When the force with which the shaft member 75 presses the piston 18, in other words, the braking force of the vehicle reaches a predetermined value, the electronic control unit 38 stops energizing the electric motor 35 of the motor gear unit 36, The drive (rotation) of the spindle 48 in the apply direction is stopped. The electronic control unit 38 can calculate the force of the shaft member 75 pressing the piston 18 (thrust force of the shaft member 75) based on the current value of the electric motor 35, for example.

As described above, the sliding screw engaging portion 45 has a reverse efficiency of 0 or less, so that the rotational torque of the spindle 48 can be converted into an axial thrust toward the other end of the shaft member 75. Axial thrust to 75 cannot be converted to spindle 48 rotational torque. As a result, when the electronic control unit 38 stops energizing the electric motor 35, the shaft member 75 maintains the stopped state even if the reaction force of the pressing force from the disk rotor D acts via the piston 18. be able to. As a result, the piston 18 is held in the braking position and the parking brake operation is completed. When the parking brake is fully activated, the reaction force of the pressing force from the disk rotor D is applied to the caliper body 6 via the thrust plate 92, thrust balls 99, shaft member 75, spindle 48, thrust balls 65, and base plate 60. is transmitted to the bottom portion 13 of the cylinder 10 and serves as a holding force for the piston 18 .

When the electronic control unit 38 receives a release command (parking brake release command) such as operation of the parking switch 39, it energizes the electric motor 35 of the motor gear unit 36 to rotate the spindle 48 in the release direction. The rotational torque transmitted to the spindle 48 is transmitted to the shaft member 75 via the sliding screw engagement portion 45 between the male threaded portion 50 of the spindle 48 and the female threaded portion 84 of the shaft member 75, and moves the shaft member 75 in the release direction. Relative rotation. The rotational torque transmitted to the shaft member 75 is transmitted to the planetary rollers 76 via the engaging portions between the annular grooves 83 of the shaft member 75 and the annular peaks 110 of the planetary rollers 76 .

The rotational torque transmitted to the planetary rollers 76 is transmitted to the nut member 77 via the engaging portions (meshing portions) between the annular ridges 110 of the planetary rollers 76 and the female threads 155 of the nut member 77. be. The nut member 77 is supported so as not to rotate relative to the cylinder portion 7 by engagement between the stopper protrusions 160 and 160 and the accommodation recesses 15 , 15 . It revolves around the axis of the nut member 77 in the release direction while rotating around the rotation axis. At this time, axial thrust is generated in each planetary roller 76 in accordance with the transmitted rotational torque to one end side, that is, in the direction opposite to that during the apply operation. The axial thrust force generated in each planetary roller 76 is transmitted to the shaft member 75 via the engagement portion between each annular peak portion 110 of each planetary roller 76 and each annular groove portion 83 of the shaft member 75 .

Then, an axial thrust is transmitted from each planetary roller 76 to the shaft member 75 toward one end side. At the same time, a torque reaction force acts on the slide screw engagement portion 45 between the female thread portion 84 of the shaft member 75 and the male thread portion 50 of the spindle 48 in the direction in which the slide screw engagement portion 45 is loosened. As a result, the shaft member 75 rotates along the female threaded portion 155 of the nut member 77 and moves toward the one end side, and the pressing force of the inner and outer brake pads 2 and 3 on the disc rotor D is released. When the electronic control unit 38 returns to the initial state in which a predetermined distance (clearance) is secured between the inclined portion 31 of the bottom portion 19 of the piston 18 and the contact surface 94 of the thrust plate 92, the motor gear unit 36 is stopped.

The roller holding unit 120 employed in the disc brake 1 according to the present embodiment applies an axial load in the return direction due to the rotation of the spindle 48 in the release direction, especially in the clearance region, to the shaft member 75 during the release operation. Even when (axial load toward one end side) is applied, at least the engaging portion between each planetary roller 76 and the shaft member 75 is accommodated in each first roller accommodating hole 127 of the roller cage 124. An axial load greater than or equal to the axial load (axial load toward the other end) is applied to the engaging portion between each planetary roller 76 and the shaft member 75 . As a result, necessary and sufficient frictional force (contact pressure) can be ensured at the engaging portion between each planetary roller 76 and the shaft member 75 . As a result, the rotational resistance torque (frictional force) between each planetary roller 76 and the roller cage 124 generated by the pressurized load of the compression coil spring 123 becomes the rotational resistance at the engagement portion between the shaft member 75 and each planetary roller 76. Since the torque (frictional force) is smaller than the torque (frictional force), each planetary roller 76 rotates around its own rotation axis during the release operation, and each planetary roller 76 and roller cage 124 rotate relative to the shaft member 75. can do.

Further, during the release operation, the shaft member 75 moves toward one end side while rotating relative to the spindle 48 , and the convex portion 81 formed on one end surface of the shaft member 75 is located on the other end surface of the flange portion 51 of the spindle 48 . By being engaged with the convex portion 55 , relative rotation of the shaft member 75 with respect to the spindle 48 is restricted. As a result, excessive screwing of the male threaded portion 50 of the spindle 48 into the female threaded portion 84 of the shaft member 75 is suppressed.

According to the disc brake 1 according to the present embodiment described above, the engagement recess 15 is provided on the bottom surface of the cylinder 10, and the stopper protrusion 160 is provided to protrude from one end surface of the nut member 77 toward one end side. By engaging the stopper protrusion 160 of the nut member 77 with the engaging recess 15 of the cylinder 10, the nut member 77 can be supported so as not to rotate relative to the caliper body 6 (cylinder portion 7). . As a result, there is no need for the pin member, which is conventionally required, and the press-fitting process for press-fitting the pin member into the bottom surface of the cylinder is not required. As a result, the number of parts can be reduced, the assembly process can be simplified, and mass production can be handled without any problem. Moreover, since the press-fitting process of the pin member is not required, the equipment for press-fitting is not required, and the production equipment can be minimized. Moreover, since the engaging recess 15 provided in the bottom surface of the cylinder 10 is formed by the core placed in the casting mold, the machining time can be shortened, and the manufacturing cost can be suppressed.

As the disc brake 1 based on the present embodiment described above, for example, the following modes are conceivable.
A first aspect includes a pair of pads (2, 3) arranged on both sides of the rotor (D) in the axial direction across the rotor (D), and one of the pair of pads (2, 3). A caliper body (6) having a piston (18) for pressing (2) against the rotor (D), a cylinder (10) in which the piston (18) is slidably fitted, and the caliper body (6) a motor (35) provided in the caliper body (6), and a rotation/linear motion conversion mechanism (37) that converts the rotary motion of the motor (35) into linear motion to propel the piston. , the rotation-to-linear motion conversion mechanism (37) includes a tubular member (77) having a protrusion (160) projecting from one end in the axial direction; a shaft member (75) to which the rotational motion from the motor (35) is transmitted; and the cylinder (10) has an engagement recess (15) with which the projection (160) engages on the bottom surface thereof. It is formed.

A second aspect includes a pair of pads (2, 3) arranged on both sides of the rotor (D) in the axial direction across the rotor (D), and one of the pair of pads (2, 3). A caliper body (6) having a piston (18) for pressing (2) against the rotor (D), a cylinder (10) in which the piston (18) is arranged so as to protrude, and a caliper body (6) provided with and a piston propulsion mechanism (37) provided in the cylinder (10) for propelling the piston (18), wherein the piston propulsion mechanism (37) drives the cylinder (10). an input member (48) extending in the axial direction and having a threaded portion (50) formed on its outer peripheral surface to which rotation from the motor (35) is transmitted; and the screw of the input member (48). It has an engaging threaded portion (84) that meshes with the portion (50), and when the input member (48) rotates, it moves in the axial direction of the cylinder (10) and moves to the piston (18) from the motor (35). and a projection (160) disposed radially outside the rotary linear motion member (75) and projecting from one end in the axial direction. and a support member (77) arranged between the support member (77) and the rotary linear motion member (75) so as to be engaged with both, and the rotation of the input member (48) causes the When the rotary linear motion member (75) rotates, a rotational resistance is applied to the rotary linear motion member (75) to rotate the rotary linear motion member (75) relative to the input member (48). and a rolling element (76) to be moved, and an engagement recess (15) is formed in the bottom surface of the cylinder (10) with which the projection (160) of the support member (77) engages.

According to a third aspect, in the first or second aspect, the protrusions (160, 160) and the engaging recesses (15, 15) are formed at two locations, respectively.

1 disc brake, 2 inner brake pad (pad), 3 outer brake pad (pad), 4 caliper, 6 caliper body, 10 cylinder, 15 engagement recess, 18 piston, 35 electric motor (motor), 37 piston propulsion mechanism ( rotation/linear motion conversion mechanism), 48 spindle (input member), 50 male threaded portion (screw portion), 84 female threaded portion (engagement threaded portion), 75 shaft member (shaft member, rotary/linear motion member), 76 planetary roller (roller moving body), 77 nut member (cylindrical member, support member), 160 stopper projection (projection), D disk rotor (rotor)

Claims (3)

a pair of pads arranged on both sides of the rotor in the axial direction across the rotor;
a piston that presses one of the pair of pads against the rotor;
a caliper body having a cylinder in which the piston is slidably fitted;
a motor provided in the caliper body;
a rotation-to-linear motion conversion mechanism provided in the caliper body for converting rotary motion of the motor into linear motion to propel the piston;
The rotation-to-linear motion conversion mechanism is
a cylindrical member having a projection projecting from one end face in the axial direction;
a shaft member disposed inside the cylindrical member and to which rotational motion from the motor is transmitted;
with
A base plate positioned inside the cylinder is disposed on the inner peripheral side of one end along the axial direction of the cylindrical member,
The protrusion protrudes from the base plate to a side opposite to the rotor,
A disc brake, wherein the cylinder has an engagement recess formed on the bottom surface thereof with which the protrusion of the tubular member engages. a pair of pads arranged on both sides of the rotor in the axial direction across the rotor;
a piston that presses one of the pair of pads against the rotor;
a caliper body having a cylinder in which the piston is protrusively arranged;
a motor provided in the caliper body;
a piston propulsion mechanism provided in the cylinder for propelling the piston;
with
The piston propulsion mechanism is
an input member that extends axially in the cylinder, has a threaded portion formed on an outer peripheral surface thereof, and transmits rotation from the motor;
A cylindrical rotary linear motion member having an engaging threaded portion that meshes with the threaded portion of the input member and that moves in the axial direction of the cylinder as the input member rotates to transmit torque from the motor to the piston. When,
a cylindrical support member disposed radially outward of the rotary linear motion member and having a projecting portion projecting from one end surface in the axial direction;
The rotary linear motion member is arranged between the support member and the rotary linear motion member so as to be engaged with both, and when the rotary linear motion member rotates due to the rotation of the input member, a rotational resistance is applied to the rotary linear motion member. a rolling element for linearly moving the rotary linear motion member while relatively rotating it with respect to the input member;
with
A base plate positioned inside the cylinder is disposed on the inner peripheral side of one end along the axial direction of the support member,
The protrusion protrudes from the base plate to a side opposite to the rotor,
A disc brake, wherein the cylinder has an engagement recess formed on the bottom thereof with which the projection of the support member engages. 3. The disc brake according to claim 1, wherein the protrusion and the engagement recess are formed at two locations.

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