JP4288501B2 - Electric brake device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric braking device of high reliability capable of positively returning a piston into a position where thrust does not remain, in a motor failure. <P>SOLUTION: A caliper body 7 is provided with a stopper 39 for regulating the normal rotation exceeding a predetermined angle of a linear motion member 34 in a ball ramp mechanism 12, and a pad wear follow-up mechanism 14 comprises an adjuster 50 screwed with a piston 10, and a one-way clutch 51 for allowing the adjuster 50 to follow the normal rotation of the linear motion member 34 but to slip from the reverse rotation of the linear motion member 34. A coil spring 15 storing torque according to the rotation of a turning member 32 in a piston advancing direction is interposed between the turning member 32 and the linear motion member 34 in the ball ramp mechanism 12. In the failure of a motor 11, the turning member 32 is returned into an initial position by the torque of the coil spring 15, and the piston 10 is returned into an initial position completely separated from a brake pad, by the energizing force of a return spring 35. <P>COPYRIGHT: (C)2006,JPO&amp;NCIPI

Description

  The present invention relates to an electric brake device that generates a braking force by the torque of a motor, and more particularly to an electric brake device that has a function of automatically releasing a brake lock state caused by a motor failure.

  The electric brake device includes a caliper having a piston, a motor, and a ball ramp mechanism that converts the rotation of the motor into a linear motion and transmits the linear motion to the piston, and according to the rotation of the motor. There is a structure in which the ball ramp mechanism is operated to propel the piston, and the brake pad is pressed against the disc rotor to generate a braking force. Usually, such an electric brake device is subject to wear of the brake pad. A pad wear follow-up mechanism (pad wear compensation mechanism) for advancing the piston in response is provided.

  By the way, in this type of electric brake device, if a motor failure occurs due to disconnection of the power line during braking while thrust is generated in the piston, the thrust remains in the piston due to the internal resistance of the motor including the speed reducer. However, it is difficult to release the brake. Therefore, conventionally, in order to automatically release the brake when the motor breaks down, for example, in the one described in Patent Document 1, a piston returning motor is incorporated in a part of the reduction gear attached to the motor, and the main piston driving force is used. When the motor fails, the piston return motor is operated. However, in this case, a brake release motor is required in addition to the main motor for propelling the piston, which increases the manufacturing cost as well as increasing the caliper size. In addition, the brake release motor itself There was also a problem of lack of reliability.

Therefore, in the one described in Patent Document 2, attention is paid to the above-described pad wear tracking mechanism, and the rotation in the ball ramp mechanism is performed using the restoring force of an elastic body (spring) that stores torque during braking in the mechanism. The member is reversely rotated to return the piston to the non-braking position.
JP 2000-507333 A JP 2003-113877 A

  However, according to the brake release method described in Patent Document 2, torque is stored in the elastic body after the piston contacts the brake pad and braking force (thrust) starts to be generated. Therefore, at the return position of the piston at the time of motor failure, there is a problem that the piston remains in contact with the brake pad and thrust remains.

  The present invention has been made in view of the above-described conventional problems, and the object of the present invention is to provide a highly reliable electric brake that can reliably return the piston to a position where no thrust remains when the motor fails. To provide an apparatus.

In order to solve the above-mentioned problems, the present invention comprises a caliper comprising a piston, a motor, and a ball ramp mechanism for converting rotation of the motor into linear motion and transmitting it to the piston. An electric brake device that operates the ball ramp mechanism in response to rotation of the disc to propel the piston and presses the brake pad against the disc rotor to generate a braking force, and the piston is moved in response to wear of the brake pad. With a pad wear tracking mechanism that moves forward, the caliper body is provided with a stopper that restricts the linear motion member in the ball ramp mechanism from rotating forward beyond a predetermined angle, and the pad wear tracking mechanism is An adjuster threadedly engaged with the piston and interposed between the adjuster and the linear motion member. Although to follow the stannous, the reversal of the linear motion member and a configuration in which a one-way clutch to slip the adjuster, between the linear motion member and the rotating member constituting the ball ramp mechanism of An elastic body that stores torque according to the rotation is interposed.

In the electric brake device configured as described above, torque is stored in an elastic body independent of the pad wear following mechanism, and rotation (braking start) of the linear motion member and the rotation member in the ball ramp mechanism is performed. Accordingly, since the torque is stored in the elastic body, when the motor fails, the rotating member returns to the initial position, and the piston moves backward to a position completely separated from the brake pad.

  In the present invention, the one-way clutch and the elastic body can be constituted by a coil spring. In this case, the structure is simplified and the apparatus is not enlarged.

  According to the electric brake device of the present invention, when the motor fails, the rotating member in the ball ramp mechanism is returned to the initial position by the torque stored in the elastic body, so that the piston is completely separated from the brake pad. The thrust is no longer left in the piston, and the brake is reliably released.

  Further, when the one-way clutch and the elastic body are constituted by coil springs, the structure is simplified and the apparatus is not increased in size, so that not only cost reduction but also installation space reduction can be achieved.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.

  1 and 2 show an electric brake device as a first embodiment of the present invention. In these drawings, 1 is a caliper supported by a carrier (not shown) fixed to a non-rotating part of the vehicle so as to be floatable in the axial direction of the disk rotor D, and 2 and 3 are arranged on both sides of the disk rotor D. The brake pads 2 and 3 are supported by the carrier so as to be movable in the axial direction of the disc rotor D. The caliper 1 includes a caliper body 7 including a housing part 5 whose rear end is closed by a bottom plate part 4 and a claw part 6 extending from the housing part 5 across the disk rotor D. 6 is arranged close to the back surface of the brake pad 4 outside the vehicle. The brake pads 2 and 3 include back plates 2a and 3a and linings 2b and 3b formed integrally with the back plates 2a and 3a.

  The caliper 1 also includes a piston 10 that can contact the rear surface of the brake pad 2 inside the vehicle, a motor 11, a ball ramp mechanism 12 that converts the rotation of the motor 11 into a linear motion and transmits the linear motion to the piston 10, and a motor. A deceleration mechanism 13 that decelerates the rotation of the motor 11 and transmits it to the ball ramp mechanism 12, a pad wear tracking mechanism 14 that advances the piston 10 in response to wear of the brake pads 2 and 3, and when the motor 11 fails during braking. And a coil spring (elastic body) 15 as a brake release mechanism for automatically returning the piston 10 to the initial position and releasing the brake.

  The piston 10 includes a large-diameter main body portion 20 and a small-diameter shaft portion 21, and the main body portion 20 is disposed close to the brake pad 2 inside the vehicle, while the shaft portion 21 is a caliper main body. 7 is extended into the housing part 5. The piston 10 is fixed in the rotational direction by fitting a protrusion 23 provided on the back plate 2 a of the brake pad 2 into a recess 22 provided on the front surface of the main body 20. In addition, a dust boot 24 is disposed between the outer peripheral portion of the main body portion 20 of the piston 10 and the inner surface of the caliper main body 7 to restrict entry of foreign matter into the housing portion 5.

  The motor 11 includes a stator 25 fitted and fixed to the housing portion 5 of the caliper main body 7, and a hollow stepped rotor 26 disposed in the stator 25. One end portion of the rotor 26 is supported by the housing portion 5 via a bearing 27, and the other end portion is supported by a rotating body 30 described later via a bearing 28. The motor 11 operates to rotate the rotor 26 by a desired angle with a desired torque in response to a command from a controller (not shown). The rotation angle of the rotor 26 is the resolver rotor 29a fixed to the rotor 26 and the housing portion 5. It is detected by a rotation detector 29 comprising a resolver stator 29b fixed to the rotor. The rotating body 30 is fitted to a bearing 31 disposed in an annular groove 4a formed in the bottom plate part 4 of the housing part 5 by fitting a cylindrical part 30a projecting on the back surface thereof, thereby forming the housing part 5 (caliper). The main body 7) is rotatably supported.

  The ball ramp mechanism 12 includes a first disk (rotating member) 32 splined to the inner diameter of the rotating body 30 and a second disk (linear motion) joined to the first disk 32 via a plurality of balls 33. Member) 34. The ball 33 is interposed between three ball grooves 32a and 34a formed on the opposing surfaces of the first disk 32 and the second disk 34 in an arc shape along the circumferential direction. The second disk 34 is loosely fitted to a cylindrical adjuster 50 described later that constitutes the pad wear tracking mechanism 14. A return spring (coil spring) 35 is interposed between the adjuster 50 and the inner diameter portion of the caliper body 7, and the second disk 34 always applies the urging force of the return spring 35 via the adjuster 50. It is received and pressed to the first disk 32 side.

  On the other hand, as shown in FIG. 3, the second disk 34 is inserted into a groove 38 formed in a cylindrical portion 37 on the inner diameter side of the caliper body 7 by inserting an engaging protrusion 36 formed at the tip thereof. The rotation range is regulated. Thus, the second disk 34 is at its original position at a predetermined angular position (state shown in FIG. 3) where the engaging protrusion 36 abuts on one groove end 39 of the groove 38 of the cylindrical portion 37. In FIG. 1 and FIG. 2, rotation in the clockwise direction when viewed from the right direction (hereinafter, this direction is assumed to be normal rotation) is restricted. Therefore, the groove end 39 functions as a stopper that restricts the second disk 34 from rotating forward beyond a predetermined angle. As a result, when the first disk 32 rotates clockwise from the state where the second disk 34 is positioned at the original position, each ball 33 rolls on the inclined surface of the groove bottom of each ball groove 32a, 34a. Then, the second disk 34 moves forward and backward with respect to the disk rotor D.

  The speed reduction mechanism 13 is fitted with an eccentric shaft 41 that is integral with the rotor 26, and is rotatably fitted to the eccentric shaft 41 via a bearing 42, and first and second gears (external gears) 43 are provided on the outer peripheral portion. , 44, a fixed gear (internal gear) 46 that is provided on the inner periphery of the housing portion 5 of the caliper body 7 and meshes with the first gear 43 of the eccentric wheel 45, and the rotating body 30. The movable gear (internal gear) 47 is provided and meshes with the second gear 44. The eccentric wheel 45 revolves according to the rotation of the eccentric shaft 41 (rotor 26) by meshing with the fixed gear 46 and the movable gear 47. At this time, since the number of teeth of the fixed gear 46 and the number of teeth of the movable gear 47 are different, the first disk 32 rotates with the rotor 26 at a constant rotation ratio (reduction ratio).

Here, the Z ₁ the number of teeth of the first gear 43, Z ₂ the number of teeth of the second gear 44, n ₁ the number of teeth of the fixing gear 46, and the number of teeth of the movable gear 47 and n _2, Z ₁ = N ₁ and the reduction ratio N is N = 1− (Z ₂ / n ₂ ). Therefore, now, when the rotor 26 of the motor 11 rotates by a certain rotation angle θ, the rotation angle of the first disk 32 becomes θ · N. In this case, the inclination (lead) of the ball grooves 32 a and 34 a of the ball ramp mechanism 12 is made. Assuming L, the second disk 34 moves forward by S = (L / 360) × (θ · N).

  The pad wear following mechanism 14 includes the cylindrical adjuster 50 and a one-way clutch 51 interposed between the adjuster 50 and the second disk 34 of the ball ramp mechanism 12. The adjuster 50 is operatively connected to the piston 10 via a threaded portion 52 formed on the inner surface thereof and thus comprising a screw and a male thread formed on the outer periphery of the shaft portion 21 of the piston 10. Here, the one-way clutch 51 is formed of a coil spring, and the adjuster 50 is made to follow the normal rotation of the second disk 34 of the ball ramp mechanism 12, but the adjuster 50 is made to reversely rotate the second disk 34. Has the function of slipping.

  The adjuster 50 and the one-way clutch 51 constituting the pad wear following mechanism 14 maintain the original position where the second disk 34 contacts the stopper (groove end) 39 of the caliper body 7 during normal braking. The two discs 34 move forward and backward with respect to the disc rotor D, and the piston 10 follows the movement. On the other hand, when the second disk 34 reverses from the original position, the adjuster 50 maintains its position without rotating. Therefore, when the second disk 34 subsequently rotates forward, the adjuster 50 follows the forward rotation. Then rotate. When the adjuster 50 rotates, the piston 10 that is operatively connected to the adjuster 50 via the threaded portion 52 moves forward, and the position of the piston 10 relative to the second disk 34 is displaced, thereby compensating for pad wear.

  Here, a predetermined pad clearance is normally secured between the piston 10 and the brake pad 2, and this pad clearance is first eliminated as the piston 10 moves forward. When the pad clearance is eliminated, the brake pad 2 is pressed against the disc rotor D, and the caliper 1 is moved relative to the carrier by the pressing reaction force (right side in FIG. 1). The brake is started by being sandwiched between the brake pads 2 and 3, and a thrust is generated in the piston 10 in response thereto. In the present embodiment, a thrust detection sensor 55 that detects a thrust generated in the piston 10 is disposed on the bottom plate portion 4 of the housing 5 of the caliper body 7. The thrust detection sensor 55 is composed of a load cell here, and is thrust against the first disk 32 constituting the ball ramp mechanism 12 via the rotating body 30, the thrust bearing 56a, and the receiving seat 56. Yes.

  The coil spring 15 as the brake release mechanism is interposed between the first disk 32 and the second disk 34 that constitute the ball ramp mechanism 12. The coil spring 15 is interposed between the two so as to generate a predetermined preload, whereby the second disk 34 is always in the original position in contact with the stopper (groove end) 39 of the caliper body 7. maintain. On the other hand, when the first disk 32 rotates in the braking direction (piston propulsion direction) from this state, the position of the second disk 34 is fixed, so that torque is stored in the coil spring 15, and in the unlikely event of braking. When the motor 11 fails, the first disk 32 is returned to the initial position by the torque stored in the coil spring 15.

  Hereinafter, the operation of the electric brake device configured as described above will be described with reference to FIGS.

  During non-braking, the ball 33 of the ball ramp mechanism 12 is at the deepest end (initial position) of the ball grooves 32a and 34a, and the first disk 32 and the second disk 34 are in the closest state. In this state, the second disk 34 is in the original position where it abuts against the stopper 39 of the caliper body 7, and the piston 10 is positioned away from the brake pad 3 by the pad clearance.

  During normal braking, when the rotor 26 of the motor 11 rotates counterclockwise as viewed from the right in FIGS. 1 and 2 in response to a command from a controller (not shown) (hereinafter, clockwise and counterclockwise expressions are illustrated) 1 and 2 viewed from the right), the eccentric wheel 45 constituting the speed reduction mechanism 13 revolves, and in response to this, the first disk (rotating member) 32 in the ball ramp mechanism 12 is connected to the rotor 26. It rotates clockwise with the constant rotation ratio (reduction ratio N) described above. Then, the ball 33 in the ball ramp mechanism 12 rolls between the ball grooves 32 a and 34 a, whereby the second disk (linear motion member) 34 moves forward, and the forward movement constitutes the pad wear tracking mechanism 14. Is transmitted to the piston 10 through the adjuster 50. When there is no pad wear, as shown in FIGS. 4 and 5, the piston 10 is displaced (advanced) from the original position A to the position B where the pad clearance is eliminated, and braking is started by further advancement of the piston 10. Accordingly, thrust is generated in the piston 10. The displacement amount of the piston 10 increases linearly to the position C in accordance with the increase in the rotation angle of the first disk 32, thereby establishing complete braking. During this time, torque is stored in the coil spring 15 as a brake release mechanism.

  When the brake is released, the rotor 22 of the motor 20 is rotated in the opposite direction (clockwise) to that during the braking, and the ball 33 returns to the initial position of the ball grooves 32a and 34a accordingly. At this time, since the urging force of the return spring 35 acts on the second disk 34, the second disk 34 and the adjuster 50 constituting the pad wear follow-up mechanism 14 return integrally, and in response to this, the piston 10 In addition, the initial position is returned in the order of C → B → A. This releases the braking force and completes one braking cycle.

When there is pad wear, for example, the controller is activated by a switch operation before starting the automobile, and the motor 11 rotates to the thrust generation point according to a command from the controller. The thrust generating point can be confirmed by the thrust detection sensor 5 5, therefore, the value obtained by subtracting the corresponding angles from the pad a clearance (rotation angle of the first disk 32) rotation angle therebetween of the rotor 26 is pad Wear amount. Next, the controller rotates the rotor 26 of the motor 11, that is, the first disk 32 by the angle corresponding to the pad wear amount in the direction opposite to that during braking. Then, the second disk 34 follows (reversely rotates) the movement of the first disk 32.

  With respect to the reverse rotation of the second disk 34 described above, the one-way clutch 51 constituting the pad wear tracking mechanism 14 slips, so that the adjuster 50 does not rotate, and the piston 10 maintains the current position (FIG. 4). 5 A → D). Thereafter, the first disk 32 is rotated forward in the piston propulsion direction by the same angle as in the reverse rotation by the operation of the motor 11. Then, the second disk 34 follows (forwardly) the movement of the first disk 32, whereby the one-way clutch 51 becomes the tightening direction and the adjuster 50 rotates. On the other hand, when the adjuster 50 rotates, the piston 10 screwed to the adjuster 50 moves forward, and at the stage where the second disk 34 returns to the original position where it abuts against the stopper 39 of the caliper body 7, the piston 10 leaves the pad clearance. It moves forward to the position E (FIGS. 4 and 5). Therefore, thereafter, as in the case of normal braking, the piston 10 moves forward and backward in accordance with forward and reverse rotation of the first disk 32 (E → F → G → F → E in FIGS. 4 and 5), and braking and braking are performed. Release is performed.

  Thus, if the motor 11 fails during braking, the first disk (rotating member) 32 of the ball ramp mechanism 12 rotates in the opposite direction to that during braking by the torque stored in the coil spring 15 during braking. Then, as in the case of normal braking release, the ball 33 returns to the initial position of the ball grooves 32a, 34a, and the second disk 34 and the adjuster 50 constituting the pad wear tracking mechanism 14 return integrally, and accordingly The piston 10 also moves backward. At this time, since sufficient torque is stored in the coil spring 15, the first disk 32 returns to the initial angular position as shown in FIG. It returns to a position where a predetermined pad clearance is opened, that is, a position where no thrust remains, and as a result, braking is completely released.

  FIG. 6 shows an electric brake device as a second embodiment of the present invention. Since the basic structure of the second embodiment is the same as that of the first embodiment, the same elements as those shown in FIGS. Is omitted. In the second embodiment, a cylindrical skirt portion 60 is integrally provided on the back side of the first disk (rotating member) 32 constituting the ball ramp mechanism 12, and the skirt portion 60 is provided on the bottom plate portion 4 of the housing 5. It is made to fit in the bearing 62 arrange | positioned at the annular boss | hub part 61 provided in the inner surface. In the second embodiment, a plurality of rolling elements 63 functioning as thrust bearings are interposed between the first disk 32 and the receiving seat 56 of the thrust detection sensor 55.

  A movable gear 47 constituting the speed reduction mechanism 13 is provided on the skirt portion 60 of the first disk 32. The movable gear 47 is an external gear here, and therefore the second gear 44 of the eccentric wheel 45 that meshes with the movable gear 47 is configured as an internal gear. The operation of the speed reduction mechanism 13 is substantially the same as that of the first embodiment, and the eccentric wheel 45 has a fixed gear 46 provided on the caliper body 7 and a movable gear 47 provided on the skirt portion 60 of the first disk 32. , So that the first disk 32 rotates with a constant rotation ratio (reduction ratio) with the rotor 26.

  According to the second embodiment, the first disk 32 constituting the ball ramp mechanism 12 can be directly rotated to the housing portion 5 (caliper body 7) without passing through the rotating body 30 (FIGS. 1 and 2). Therefore, since the rotating body 30 is omitted, the number of parts is reduced, which is advantageous in terms of cost compared to the first embodiment.

  FIG. 7 shows an electric brake device as a third embodiment of the present invention. Since the basic structure of the third embodiment is the same as that of the first embodiment, the same components as those shown in FIGS. Is omitted. The third embodiment is characterized in that the ball ramp mechanism 12 is disposed around the piston 10 and the return spring 35 is provided with a first disk (rotating member) 32 constituting the ball ramp mechanism 12 and a second. It is set between the disk (linear motion member) 34 and the speed reduction mechanism 13 is collectively disposed in the rotor 26 of the motor 11.

  More specifically, the first disk (rotating member) 32 constituting the ball ramp mechanism 12 is provided via a key 72 on a cup-shaped rotating body 71 that is rotatably disposed on the caliper body 7 using a bearing 70. Are coupled so that they cannot rotate relative to each other. The second disk 34 is formed by extending a cylindrical portion 34a provided on the inner diameter side thereof through the gap between the adjuster 50 constituting the pad wear follow-up mechanism 14 and the first disk 32 toward the bottom plate portion 4 side of the housing portion 5. ing. A ring stopper 73 is fixed to an extended end portion of the cylindrical portion 34a of the second disk 34. Between the ring stopper 73 and the back surface of the first disk 32, the return spring 35 and a brake release mechanism are provided. A coil spring 15 is interposed.

  On the other hand, a shaft member 74 having a fixed gear 46 constituting the speed reduction mechanism 13 is disposed at the axial center position inside the rotor 26. The shaft member 74 is splined at its base end to a cylindrical boss portion 75 provided on the bottom plate portion 4 of the housing portion 5, and its distal end portion is loosely inserted into the inner diameter portion of the rotating body 71. . The fixed gear 46 is an external gear, and therefore the first gear 43 of the eccentric wheel 45 that meshes with the fixed gear 46 is configured as an internal gear. A movable gear 47 that also constitutes the speed reduction mechanism 13 is provided on the outer peripheral portion on the back side of the rotating body 71. The movable gear 47 is an internal gear as in the first embodiment. Therefore, the second gear 44 of the eccentric wheel 45 that meshes with the movable gear 47 is configured as an external gear. The operation of the speed reduction mechanism 13 is substantially the same as that of the first embodiment, and the eccentric wheel 45 includes a fixed gear 46 provided on the shaft member 74 (caliper body 7) and the rotating body 71 (first disk 32). The first disk 32 rotates with a constant rotation ratio (reduction ratio) with the rotor 26 by revolving according to the rotation of the eccentric shaft 41 (rotor 26).

  In the third embodiment, the thrust detection sensor 55 is formed in an annular shape and is fitted into the cylindrical boss portion 75 of the bottom plate portion 4 so that the stepped surface on the base end side of the shaft member 74 is formed. A plurality of rolling elements 76 functioning as thrust bearings with a rotating body 71 integrated with the first disk 32 are provided on the stepped surface of the shaft member 74 at the front end side of the shaft member 74 while abutting with the thrust detection sensor 55 via a receiving seat 56. Through.

  According to the third embodiment, since the return spring 35 is disposed outside the cylindrical portion 34a of the second disk 34 fitted to the adjuster 50, the first embodiment in which the return spring 35 is wound around the adjuster 50. Compared to the configuration, the diameter of the return spring 35 is enlarged, and the spring force of the return spring 35 can be increased correspondingly, and as a result, the return of the piston 10 when the motor fails is smooth. In the third embodiment, since the first disk 32 is operatively connected to the thrust detection sensor 55 via the rolling element 76 functioning as a thrust bearing, the first disk 32 of the first disk 32 is similar to the second embodiment. Smooth rotation.

FIG. 8 shows an electric brake device as a fourth embodiment of the present invention. Since the basic structure of the fourth embodiment is the same as that of the first embodiment, the same components as those shown in FIGS. Is omitted. A feature of the fourth embodiment is that a cylindrical portion 80 is provided in the main body portion 20 of the piston 10, and the cylindrical portion 80 is slid on a cylinder portion 81 formed in the caliper main body 7 via a seal member 82. It is in the point inserted so that movement is possible. Here, the piston 10 has a divided structure in which the main body portion 20 and the shaft portion 21 are formed separately, and both are combined. The rotating body 30 including the movable gear 47 constituting the speed reduction mechanism 13 is supported by a support body 83 fitted and fixed to the housing portion 5 through a bearing 84 here.
According to the fourth embodiment, since the piston 10 slides in the cylinder portion 81 of the caliper main body 7, the movement thereof is stable, a stable braking force can be obtained, and the brake release is also stabilized. Become.

FIG. 9 shows an electric brake device as a fifth embodiment of the present invention. Since the basic structure of the fifth embodiment is the same as that of the first embodiment, the same elements as those shown in FIGS. Is omitted. The feature of the fifth embodiment is that the entire piston 10 is formed in a cup shape, and the cylindrical portion 90 is formed in the caliper body 7 as in the fourth embodiment (FIG. 8). The part 81 is slidably inserted through a seal member 82. The screw portion 52 for operatively connecting the adjuster 50 and the piston 10 constituting the pad wear following mechanism 14 is formed of a screw and a male screw formed on the adjuster 50 to be formed in the cylindrical portion 90 of the piston 10. ing. In the fifth embodiment, a stopper 39 that restricts the rotation of the second disk (linear motion member) 34 of the ball ramp mechanism 12 is set on the cylindrical body 91 that is splined to the outer periphery of the cylinder portion 81. Yes. On the other hand, the return spring 35 and the coil spring 15 as a brake release mechanism are disposed using the space S in the piston 10 (adjuster 50). More details. One end of a shaft member 92 that is spline-fitted to the inner diameter portion of the first disk (rotating member) 32 of the ball ramp mechanism 12 extends into the space S and is a ring that is fixed to the distal end portion of the shaft member 92. A return spring 35 and a coil spring 15 are disposed between the stopper 93 and the second disk 34. In the fifth embodiment, the rotating body 30 having the movable gear 47 constituting the speed reduction mechanism 13 is also splined to the shaft member 92.
According to the fifth embodiment, since the screw portion 52 for operatively connecting the adjuster 50 and the piston 10 has a larger diameter than that of the first embodiment, the screw strength is increased and the meshing length is reduced. Therefore, the caliper 1 can be reduced in size. Further, since the rigidity of the screw can be increased, the rigidity of the caliper 1 can be increased.

FIG. 10 shows an electric brake device as a sixth embodiment of the present invention. Since the basic structure of the sixth embodiment is the same as that of the fifth embodiment, the same components as those shown in FIG. 9 are denoted by the same reference numerals and redundant description is omitted. To do. A feature of the sixth embodiment is that a hat-shaped portion 100 is provided at one end of a shaft member 92 splined to the first disk 32 of the ball ramp mechanism 12, and the return spring 35 and the hat-shaped portion 100 are provided in the hat-shaped portion 100. The coil spring 15 as a brake release mechanism is supported. In the sixth embodiment, a plurality of rolling elements 101 functioning as thrust bearings are interposed between the rotating body 30 splined to the shaft member 92 and the receiving seat 56 of the thrust detection sensor 55. .
According to the sixth embodiment, since it is not necessary to fix the ring stopper 93 (FIG. 9) to the shaft member 92 as in the fifth embodiment, the number of parts is reduced and assembly is facilitated.

It is a longitudinal section showing the whole electric brake device structure as a 1st embodiment of the present invention. It is a longitudinal cross-sectional view which shows the principal part structure of the electric brake device shown in FIG. It is sectional drawing which shows the stopper structure which controls rotation of the linear motion member of the ball ramp mechanism in the electric brake device shown in FIG. It is a graph which shows the relationship between the rotation angle (rotation position) of the rotation member of the ball ramp mechanism in this 1st Embodiment, and piston displacement. It is a time chart which shows the time change of the component of the ball ramp mechanism in this 1st embodiment, the component of a wear following mechanism, and the displacement of a piston. It is sectional drawing which shows the principal part structure of the electric brake device as 2nd Embodiment of this invention. It is sectional drawing which shows the principal part structure of the electric brake device as 3rd Embodiment of this invention. It is sectional drawing which shows the principal part structure of the electric brake device as 4th Embodiment of this invention. It is sectional drawing which shows the principal part structure of the electric brake device as 5th Embodiment of this invention. It is sectional drawing which shows the principal part structure of the electric brake device as 6th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Caliper 2,3 Brake pad 10 Piston 11 Motor 12 Ball ramp mechanism 13 Deceleration mechanism 14 Pad wear follow-up mechanism 15 Coil spring (elastic body)
32 First disk (rotating member) of ball ramp mechanism
33 Ball of ball ramp mechanism 34 Second disc of ball ramp mechanism (linear motion member)
50 Adjuster (Pad wear tracking mechanism)
51 One-way clutch (pad wear tracking mechanism)
55 Thrust detection sensor D Disc rotor

Claims (3)

A caliper comprising a piston, a motor and a ball ramp mechanism for converting the rotation of the motor into a linear motion and transmitting it to the piston is provided in the caliper body, and the ball ramp mechanism is operated according to the rotation of the motor. An electric brake device that propels the piston and presses a brake pad against a disc rotor to generate a braking force,
In what has a pad wear tracking mechanism that advances the piston in accordance with the wear of the brake pad,
The caliper body is provided with a stopper for restricting the linear motion member in the ball ramp mechanism from rotating forward beyond a predetermined angle, and the pad wear tracking mechanism includes an adjuster screwed to the piston, and the adjuster. And a one-way clutch that causes the adjuster to follow the forward rotation of the linear motion member, but slips the adjuster to reverse the linear motion member. An electric body characterized in that an elastic body that stores torque according to the rotation of the rotating member in the piston propulsion direction is interposed between the linear member and the rotating member constituting the ball ramp mechanism. Brake device. The electric brake device according to claim 1, wherein the elastic body is a coil spring. A caliper comprising a piston, a motor and a ball ramp mechanism for converting the rotation of the motor into a linear motion and transmitting it to the piston is provided in the caliper body, and the ball ramp mechanism is operated according to the rotation of the motor. An electric brake device that propels the piston and presses a brake pad against a disc rotor to generate a braking force,
In what has a pad wear tracking mechanism that advances the piston in accordance with the wear of the brake pad,
The caliper body is provided with a stopper for restricting the linear motion member in the ball ramp mechanism from rotating forward beyond a predetermined angle, and the pad wear tracking mechanism includes an adjuster screwed to the piston, and the adjuster. And a one-way clutch that causes the adjuster to follow the forward rotation of the linear motion member, but slips the adjuster to reverse the linear motion member. An electric body characterized in that an elastic body that stores torque by a rotational difference between the linear motion member and the rotational member is interposed between the linear motion member and the rotational member constituting the ball ramp mechanism. Brake device.

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