JP2007321862A - Motor driven disc brake - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor driven disc brake with a parking brake function for preventing damage to a parking brake mechanism. <P>SOLUTION: A motor 39 is energized to rotate a motor rotor 48. The rotation is decelerated by a differential decelerating mechanism 20. Beside, a ball ramp mechanism 19 converts the rotation into linear motion to move a piston 14 forward, and brake pads 4, 5 are thrust against a disc rotor 2 to generate braking force. With the operation of the parking brake mechanism 41, an engaging claw member 54 engages with a ratchet 52 mounted on the motor rotor 48 to lock the rotation of the motor rotor 48, thereby holding a braking condition in a deenergized state. An elastic member 60 is mounted on the ratchet 52 for absorbing impact load which is generated when the engaging claw member 54 engages the ratchet 52 to reduce impact noises between the ratchet 52 and the engaging claw member 54 and prevent damage thereto. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electric disc brake that generates a braking force by pressing a brake pad against a disc rotor by an electric motor, and more particularly to an electric disc brake having a parking brake function that can maintain a braking force in a non-energized state. It is.

  As an electric disc brake, the rotary motion of the rotor of the electric motor is converted into a linear motion of the piston using a rotation-linear motion conversion mechanism such as a ball screw mechanism or a ball ramp mechanism, and the brake pad is pressed against the disc rotor by the piston. Thus, a device that generates a braking force is known. The electric disc brake generates a desired braking force by detecting a driver's brake pedal depression force (or displacement amount) using a sensor and controlling the rotation of the electric motor based on the detected value by a control device. Can do.

In this type of electric disc brake, for example, as described in Patent Document 1, a lock mechanism that mechanically locks the rotation of the rotor of the electric motor is provided, and the rotation of the rotor is locked by the lock mechanism in a braking state. Accordingly, there is a vehicle equipped with a parking brake function that can maintain a braking force even after energization of the electric motor is stopped.
Japanese Patent Application Laid-Open No. 2005-9633

  In the electric disc brake described in Patent Document 1, a claw wheel is attached to the rotor of the electric motor, and an engagement claw that can be engaged with and detached from the claw portion of the claw wheel by a solenoid actuator is provided. Is moved to the braking position, and the engaging claw is engaged with the claw wheel so that the braking state is maintained in the non-energized state.

  However, the electric disc brake having the parking brake function described in Patent Document 1 has the following problems. In order to reliably engage the engaging claws with the claw portions of the claw wheel, these engagements are performed while rotating the rotor of the electric motor. At this time, an impact load is applied to the claw portion and the engaging claw of the claw wheel due to the inertia of the rotor during the engagement, and the claw portion and the engaging claw may be damaged. For this reason, it is necessary to sufficiently ensure the strength of the claw portion of the claw wheel and the engaging claw, and it is very difficult to downsize them, and as a result, it is contrary to the demand for downsizing of the electric disc brake. It has become.

  The present invention has been made in view of the above points, and an object thereof is to provide an electric disc brake capable of preventing damage to a parking brake mechanism.

In order to solve the above problems, an invention according to claim 1 includes an electric motor and a rotation-linear motion conversion mechanism that converts rotation of the rotor of the electric motor into linear motion, and the rotation-linear motion conversion. A claw wheel that presses a brake pad against a disk rotor by a mechanism to generate a braking force, and further has a plurality of claw portions and is connected to the rotor or a rotating body that rotates in conjunction with the rotor; and the claw wheel A parking brake that holds a braking state by locking the rotation of the rotor by engaging the engaging claw member with the claw portion of the ratchet wheel. In the electric disc brake with mechanism,
An elastic member is interposed between the claw portion of the claw wheel and the rotor or a rotating body that rotates in conjunction with the rotor.
The electric disc brake according to a second aspect of the present invention is the configuration of the first aspect, wherein the claw wheel includes a first member having the claw portion and a second member connected to the rotor side, The first member and the second member are engaged with a gap so as to be relatively rotatable within a certain range, and the elastic member is interposed in the gap.
According to a third aspect of the present invention, there is provided the electric disc brake according to the second aspect, wherein the first member and the second member are engaged with each other with a clearance in the rotational direction by the concave and convex engaging portions. Features.

According to the electric disk brake of the first aspect of the present invention, the impact load generated when the claw portion of the claw wheel and the engaging claw member are engaged can be absorbed by the elastic member.
According to the electric disc brake of the second aspect of the invention, even if the elastic member is damaged, the rotational force can be transmitted by the engagement between the first member and the second member.
According to the electric disc brake of the invention of claim 3, even if the elastic member is damaged, the rotational force is transmitted by the engagement of the concave and convex engaging portions of the first member and the second member. Can do.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
A first embodiment of the present invention will be described with reference to FIGS. As shown in FIGS. 1 and 2, the electric disc brake 1 according to the present embodiment is a caliper floating disc brake, and includes a disc rotor 2 that rotates together with wheels, and a non-rotating portion on the vehicle body side such as a suspension member ( A carrier 3 fixed to the disk rotor 2, a pair of brake pads 4 and 5 disposed on both sides of the disk rotor 2 and supported by the carrier 3, and a pair of slide pins disposed across the disk rotor 2. 6 and 6, an electric caliper 7 supported so as to be movable along the axial direction of the disk rotor 2 with respect to the carrier 3 is provided.

  The electric caliper 7 includes a caliper body 8, a piston unit 9, and a motor unit 10. The caliper body 8 includes a cylindrical cylinder part 11 having a through hole that opens to face one side of the disk rotor 2, a claw part 12 that extends from the cylinder part 11 across the disk rotor 2 to the opposite side, and a cylinder A pair of arm portions 13 extending in a substantially diametrical direction from the portion 11 and to which the pair of slide pins 6 and 6 are respectively attached are integrally formed. A guide bore 15 into which a piston 14 (described later) of the piston unit 9 is slidably fitted and a male screw 17 of an adjusting screw 16 (described later) attached to the piston unit 9 are screwed on the inner peripheral surface of the cylinder portion 11. A mating female screw 18 is formed.

  The piston unit 9 includes a bottomed cylindrical piston 14, a ball ramp mechanism 19 (rotation-linear motion conversion mechanism) and a differential reduction mechanism 20 housed in the piston 14, and a pad wear compensation mechanism 21. It has become. The piston 14 is slidably fitted to the guide bore 15 of the caliper body 8, contacts the one brake pad 5, and is prevented from rotating by a pin 5A. The piston 14 and the guide bore 15 are sealed with a dust seal 22 and a seal ring 23.

  The ball ramp mechanism 19 is formed on a linearly moving disk 24 fixed to the bottom surface of the piston 14 and movable in the axial direction together with the piston 14, and a rotating disk 25 movable in the rotating direction. And a ball 28 inserted between the ball grooves 26 and 27 (inclined grooves). The rotating disk 25 is constantly urged toward the linear motion disk 24 by a plurality of wave washers or an integral coiled wave washer 29. When the linear motion disk 24 and the rotary disk 25 are rotated relative to each other, the balls 28 roll between the inclined ball grooves 26 and 27, so that the linear motion disk 24 and the rotary disk 25 correspond to the rotation angle. Move relative to the axis. Thereby, a rotational motion can be converted into a linear motion.

  The differential speed reduction mechanism 20 includes an eccentric shaft 30, a ring-shaped spur gear 32 having two external teeth 32A and 32B supported rotatably by bearings 31A and 31B on an eccentric portion 31 of the eccentric shaft 30, a ball ramp An internal tooth 33 formed on the rotary disk 25 of the mechanism 19 and meshing with one external tooth 32A of the spur gear 32, and the other external tooth of the spur gear 32 supported rotatably with respect to the rotational shaft of the eccentric shaft 30. And a ring gear member 35 having internal teeth 34 that mesh with 32B. One end of the eccentric shaft 30 is rotatably supported by the rotary disk 25, the other end is extended into the motor unit 10, and an outer spline 36 is formed at the tip. One end of the ring gear member 35 is in contact with the end of the rotating disk 25 via a thrust bearing 37. Then, by rotating the eccentric shaft 30 and revolving the spur gear 32, the ring gear member having the rotary disk 25 having the internal teeth 33 meshing with the external teeth 32A of the spur gear 32 and the internal teeth 34 meshing with the external teeth 32B. 35 is differentially rotated, and by fixing one of these, the other can be decelerated and rotated at a predetermined reduction ratio.

  The pad wear compensation mechanism 21 includes a limiter 38 mounted between the linear motion disk 24 and the rotary disk 25 of the ball ramp mechanism 19, an adjustment screw 16 coupled to the ring gear member 35 of the differential reduction mechanism 20, and an adjustment. A wave washer 38A interposed between the ring gear member 35 connected to the screw 16 and the piston 14 is provided. The limiter 38 applies a biasing force in the return direction with a certain amount of play between the linear motion disk 24 and the rotary disk 25 by a torsion spring. The adjustment screw 16 has a male screw 17 (trapezoidal screw) formed on the outer periphery thereof, and this male screw 17 is screwed to a female screw 18 (trapezoidal screw) formed on the cylinder portion 11 of the caliper body 8. The adjustment screw 16 is held by the wave washer 38A so as not to rotate with a constant holding force, and is moved in the axial direction by the relative rotation of the male screw 17 and the female screw 18 by rotating against the holding force. Can do. The adjusting screw 16 receives the reaction force from the rotary disk 25 via the thrust bearing 37 and the gear member 35 and transmits the reaction force to the caliper body 8 via the male screw 17 and the female screw 18.

  The motor unit 10 is integrated with a motor 39 (electric motor), a resolver 40 for detecting the rotational position of the motor 39, and a parking brake mechanism 41 for holding the rotational position of the motor 39. The motor 39 includes a cylindrical motor case 44 that is attached to the base plate 43 coupled to the end of the caliper body 8 and is inserted into the adjustment screw 16 of the piston unit 9. A coil or the like is provided on the inner periphery of the motor case 44. A motor stator 45 is fixed. The motor case 44 includes a bottomed cylindrical motor case main body 44A and a motor case lid 44B that closes the opening thereof. Bearings 46 and 47 are attached to openings provided in the motor case main body 44A and the motor case lid 44B. A cylindrical motor rotor 48 (rotor) is rotatably supported by these bearings 46 and 47. The motor case 44 abuts on the inner periphery of the cylinder portion 11 of the caliper body 8 and is supported in the radial direction. An inner spline 49 that engages with the outer spline 36 of the eccentric shaft 30 of the piston unit 9 is formed on the inner peripheral portion of the motor rotor 48, and transmits rotational force between the motor rotor 48 and the eccentric shaft 30. These can be moved relative to each other in the axial direction.

  The resolver 40 includes a resolver stator 50 fixed to the base plate 43, and a resolver rotor 51 that is attached to the tip of the motor rotor 48 inserted through the base plate 43 and is positioned on the inner periphery of the resolver stator 50. An electrical signal indicating the rotational position of the motor rotor 48 is output by relative rotation.

  As shown mainly in FIG. 2, the parking brake mechanism 41 is disposed on the outer peripheral side of the claw wheel 52 attached to the motor rotor 48 and on the outer peripheral side of the claw wheel 52, and is rotatably supported by the base plate 43. An engaging claw member 54 and a solenoid actuator 55 that is fixed to the base plate 43 and drives the engaging claw member 54 are provided.

  The claw wheel 52 is fitted to the rear end portion (right end portion in FIG. 1) of the motor rotor 48 and is fixed so as to rotate together with the motor rotor 48 by a key 56. A large number of claw portions 57 are formed on the outer peripheral portion of the claw wheel 52 at regular intervals. The claw wheel 52 includes an inner peripheral member 58 (second member) on the inner peripheral side that fits in the motor rotor 48, an outer peripheral member 59 (first member) on the outer peripheral side where the claw portion 57 is formed, and these members. And an elastic member 60 made of an elastic body such as rubber interposed therebetween. The outer peripheral portion of the inner peripheral member 58 and the inner peripheral portion of the outer peripheral member are formed with concave and convex engaging portions 61 and 62 that can be engaged with each other with a predetermined gap in the rotation direction. The elastic member 60 is filled in the gap between the engaging portions 62, and the inner peripheral member 58 and the outer peripheral member 59 are integrally coupled. Thereby, the inner peripheral member 58 and the outer peripheral member 59 can be relatively rotated by a certain range by elastic deformation of the elastic member 60.

  The engaging claw member 54 has an engaging claw portion 63 formed at one end, and the engaging claw portion 63 is engaged with one of the claw portions 57 of the claw wheel 52 by rotating about the pin 53. If you can, you can leave. The claw portion 57 of the claw wheel 52 and the engagement claw portion 63 of the engagement claw member 54 are formed in a bowl shape having an inclination in a fixed direction, and when engaged with each other, the counter clock in FIG. The rotation in the direction (braking release direction) is locked, and the force for rotating the engaging claw member 54 in the unlocking direction is generated for the rotation in the clockwise direction (braking direction). ing. Moreover, in this Embodiment, although the claw part 57 of the claw wheel 52 is formed in the shape where the top part and the bottom part are flat, it does not need to have such a flat shape.

  The solenoid actuator 55 has a distal end portion of the operating rod 55A connected to the other end portion of the engaging claw member 54. The energizing claw member 54 is rotated by energization, and the engaging claw portion 63 is moved to the claw wheel 52. The claw portion 57 can be engaged and disengaged. More specifically, the actuating rod 55A has a compression spring 55B on its outer periphery, and the engagement claw 63 is normally disengaged from the claw 57 of the claw wheel 52 by this compression spring 55B, to the solenoid actuator 55. The engaging claw member 54 is rotated by energization of the engaging claw member 63 and the engaging claw portion 63 is engaged with the claw portion 57 of the claw wheel 52. However, the present invention is not limited thereto, and the engaging claw member 54 is rotated by energizing the solenoid actuator 55 using the compression spring 55B as a tension spring, and the engaging claw portion 63 is detached from the claw portion 57 of the claw wheel 52. You can also If a solenoid actuator 55 that can hold the solenoid actuator 55 at both ends is used without using a spring, the engaging claw member 54 is moved to the engaging / disengaging position, and then the operating rod 55A is moved to the respective positions in a non-energized state. It is also possible to hold it.

Next, the operation of the present embodiment configured as described above will be described.
At the time of braking, a control current is supplied from a controller (not shown) to the motor 39 based on the brake operation of the driving vehicle to rotate the motor rotor 48 in the braking direction. The rotation of the motor rotor 48 is decelerated at a predetermined reduction ratio by the differential reduction mechanism 20 and converted into a linear motion by the ball ramp mechanism 19 to advance the piston 14. As the piston 14 advances, one brake pad 5 is pressed against the disc rotor 2, and the caliper body 8 moves along the slide pin 6 of the carrier 3 due to the reaction force, and the claw portion 12 moves the other brake pad 4. The disc rotor 2 is pressed to generate a braking force. Further, at the time of releasing the brake, the piston 14 is moved backward by rotating the motor rotor 48 backward to separate the brake pads 4 and 5 from the disc rotor 2.

  The controller detects various vehicle conditions such as the rotational speed of each wheel, vehicle speed, vehicle acceleration, steering angle, and vehicle lateral acceleration using various sensors, and controls the rotation of the motor 39 based on these detections. Thus, boost control, antilock control, traction control, vehicle stabilization control, and the like can be executed.

Next, the operation of the differential reduction mechanism 20 and the pad wear compensation mechanism 21 will be described.
When the eccentric shaft 30 is rotated by the motor rotor 48 during braking, the spur gear 32 revolves due to the eccentric rotation of the eccentric portion 31, and the rotating disk 25 and the ring gear member 35 engaged with the external teeth 32 </ b> A and 32 </ b> B of the spur gear 32 are different. Dynamic rotation. At this time, normally, the rotation of the ring gear member 35 together with the adjusting screw 16 is fixed by the wave washer 38A, while the rotating disk 25 can freely rotate within the range of play of the limiter 38. Rotates. As a result, the ball ramp mechanism 19 advances the piston 14 and presses the brake pads 4 and 5 against the disc rotor 2. After the brake pads 4 and 5 start to press the disk rotor 2, the reaction force acts on the male screw 17 and the female screw 18, thereby increasing the frictional force between them and adjusting the screw 16, that is, the ring gear member 35. The rotation is securely locked. Therefore, the rotary disk 25 can rotate against the spring force of the limiter 38.

  When the brake pads 4 and 5 are worn and the rotating disk 25 does not press the disk rotor 2 even if it exceeds the play range of the limiter 38, the spring force of the limiter 38 acts on the rotating disk 25, and the rotating disk 25 is The adjusting screw 16 is rotated together with the ring gear member 35 against the holding force of the wave washer 38A. Thereby, the adjustment screw 16 moves forward by the relative rotation of the male screw 17 and the female screw 18 to advance the piston unit 9. When the brake pads 4 and 5 move forward by the amount of wear and press the disk rotor 2, as described above, the frictional force of the male screw 17 and the female screw 18 is increased by the reaction force, and the rotation of the adjusting screw 16 is locked. Is done. Thereafter, the rotating disk 25 rotates against the spring force of the limiter 38 and the piston 14 advances by the ball ramp mechanism 19. In this way, the piston unit 9 can be advanced by the adjusting screw 16 as much as the brake pads 4 and 5 are worn, and the wear of the brake pads 4 and 5 can be compensated.

Next, the operation of the parking brake mechanism 41 will be described.
When operating the parking brake, first, the motor rotor 48 is rotated in the braking direction to press the brake pads 4 and 5 against the disc rotor 2 with a desired force. In this state, the solenoid actuator 55 is operated to press the engagement claw portion 63 of the engagement claw member 54 against the claw portion 57 of the claw wheel 52. At this time, the claw portions 63 and the claw portions 57 may not be engaged because the top portions interfere with each other. Next, the motor rotor 48 is rotated in the braking release direction so that the engaging claw portion 63 and the claw portion 57 are reliably engaged. Then, after the energization to the motor 39 is stopped and the pressing force of the brake pads 4 and 5 to the disc rotor 2 is confirmed, the energization to the solenoid actuator 55 is stopped and the engagement claw portion 63 and the claw portion 57 Maintains the engaged state. Thereby, the braking state can be maintained in a state where energization to the motor 39 and the solenoid actuator 55 is stopped.

  At this time, when the engagement claw portion 63 of the engagement claw member 54 is engaged with the claw portion 57 of the claw wheel 52, an impact load may be generated due to the inertia of the motor rotor 48 or the like. Since the impact load can be absorbed by the elastic member 60 interposed between the member 58 and the outer peripheral member 59, the impact sound between the claw wheel 52 and the engaging claw member 54 can be reduced, and both members Can prevent damage. As a result, the parking brake mechanism 41 can be downsized. In addition, since the elastic member 60 is filled in the gap between the concave and convex engaging portions 61 and 62 that can be engaged with each other, the elastic member 60 mainly receives a compressive load and does not receive a tensile load. Excellent. If the elastic member 60 is damaged, the concave and convex engaging portions 61 and 62 are engaged with each other to transmit a rotational force between the inner peripheral member 58 and the outer peripheral member 59. Therefore, the operation of the parking brake mechanism 41 can be maintained.

  When releasing the operation of the parking brake, the energizing claw 63 of the engaging claw member 54 is not energized to the solenoid actuator 55 but slightly rotated in the braking direction by energizing the motor rotor 48. And the engagement between the claw wheel 52 and the claw portion 57 of the claw wheel 52 is loosened, and the urging force of the compression spring 55B causes the engagement claw member 54 to rotate in a direction to release the engagement between the engagement claw portion 63 and the claw portion 57 The braking force is released by rotating the motor rotor 48 in the braking release direction by the reaction force from the brake pads 4 and 5 and the spring force of the wave washer 29 or by energizing the motor rotor 48 in the braking release direction.

  Next, a second embodiment of the present invention will be described with reference to FIGS. In the following description, the same reference numerals are given to the same parts with respect to the first embodiment, and only different parts will be described in detail.

  The electric disc brake 64 according to the present embodiment is a caliper floating disc brake, and the caliper body 65 is provided with a ball screw mechanism 66 as a rotation-linear motion conversion mechanism, and the electric motor in parallel with the ball screw mechanism 66. 67 is arranged, and the ball screw mechanism 66 and the electric motor 67 are connected via a speed reduction mechanism 68. In the speed reduction mechanism 68, a small gear 70 (spur gear) attached to a shaft 69 directly connected to the rotor 67A of the electric motor 67 and a large gear 72 (spur gear) attached to the rotating portion 71 of the ball screw mechanism 66 mesh with each other. It has been done. Thereby, the rotation of the shaft 69 of the electric motor 67 is decelerated by the speed reduction mechanism 68 and transmitted to the rotation portion 71 of the ball screw mechanism 66, and the linear motion portion 73 of the ball screw mechanism 66 is advanced to move the brake pads 4, 5 Press against the disk rotor 2.

  A parking brake mechanism 41 similar to that of the first embodiment is provided on the back of the large gear 72 of the speed reduction mechanism 68. That is, the ratchet wheel 74 is attached to the motor rotor 48 in the first embodiment, but in this second embodiment, a large reduction gear mechanism 68 that is a rotating body that rotates in conjunction with the rotor 67A of the electric motor 67 is used. It is attached to the rear end of the gear 72.

  Further, the claw wheel 52 in the first embodiment is composed of the inner peripheral member 58, the outer peripheral member 59, and the elastic member 60 interposed therebetween, but the claw wheel 74 of the second embodiment. The inner peripheral member 58 and the elastic member 60 are omitted, and an outer peripheral member 59 in which a claw portion 57 is formed on the outer peripheral portion and an uneven engaging portion 61 is formed on the inner peripheral portion. A concave and convex engaging portion 75 similar to the outer peripheral portion of the inner peripheral member 58 is formed on the outer peripheral portion of the shaft portion 72A of the large gear 72, and the concave and convex engagement on the inner peripheral portion of the outer peripheral member 59 of the ratchet wheel 74 is formed. A predetermined gap is provided in the rotational direction between the joint portion 61. An elastic member 60 made of an elastic material such as rubber is interposed in the gap between the engaging portion 61 and the engaging portion 75 so that the large gear 72 and the claw wheel 74 are integrally coupled. Thereby, the large gear 72 and the claw wheel 74 can be relatively rotated by a certain range by elastic deformation of the elastic member 60.

  Further, in the electric disc brake 64 according to the present embodiment, a ball screw mechanism 66 having a relatively large stroke of the linear motion portion 73 is used as the rotation-linear motion conversion mechanism, and follows the wear of the brake pads 4 and 5. Therefore, no pad wear compensation mechanism is provided.

  Accordingly, as in the first embodiment, braking can be performed by supplying a control current to the electric motor 67 by a controller (not shown), and the parking brake mechanism 41 is operated by the solenoid actuator 55. The same operation and effect as the first embodiment can be achieved.

  As described above in the first and second embodiments, the elastic member may be interposed between the claw portion of the ratchet wheel and the rotor or the rotating body that rotates in conjunction with the rotor. .

  Further, as long as the rotating body rotates in conjunction with the rotor of the electric motor, not only the large gear 72 of the speed reduction mechanism 68 but also the rotating portion 71 of the ball screw mechanism 66 of the rotation-linear motion conversion mechanism, etc. Alternatively, the ratchet wheel 52) of the first embodiment may be attached.

  Further, a plurality of concave and convex engagements are provided so as to allow relative rotation within a certain range between the inner peripheral member 58 and the outer peripheral member 59 of the ratchet wheel 52 or between the large gear 72 and the ratchet wheel 74. Although it carried out by the combining parts 61, 62, and 75, the number, arrangement | positioning, etc. can be changed suitably and can also be implemented with another form.

1 is a longitudinal sectional view showing an electric disc brake according to a first embodiment of the present invention. It is a longitudinal cross-sectional view by the AA line of FIG. It is a longitudinal cross-sectional view of the schematic structure of the electric disc brake which concerns on 2nd Embodiment of this invention. FIG. 5 is a sectional view taken along line BB in FIG. 3 of the parking brake mechanism of the electric disc brake shown in FIG. 3.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Electric disc brake, 2 Disc rotor, 4, 5 Brake pad, 41 Parking brake mechanism, 52, 74 Claw wheel, 54 Engagement claw member, 57 Claw part, 58 Inner peripheral member (2nd member), 59 Outer peripheral member ( 1st member), 60 elastic member, 61, 62, 75 engaging part

Claims (3)

An electric motor and a rotation-linear motion conversion mechanism that converts the rotation of the rotor of the electric motor into a linear motion, and the brake pad is pressed against the disk rotor by the rotation-linear motion conversion mechanism to generate a braking force; Further, a claw wheel having a plurality of claw parts and connected to the rotor or a rotating body that rotates in conjunction with the rotor, and an engagement claw member that can be engaged with the claw part of the claw wheel are provided, In the electric disc brake provided with a parking brake mechanism that holds the braking state by locking the rotation of the rotor by engaging the engaging claw member with the claw portion of the claw wheel,
An electric disc brake, wherein an elastic member is interposed between a claw portion of the claw wheel and the rotor or a rotating body that rotates in conjunction with the rotor. The ratchet wheel includes a first member having the claw portion and a second member connected to the rotor side, and the first member and the second member have a gap that is relatively rotatable within a certain range. The electric disc brake according to claim 1, wherein the elastic member is interposed in the gap. The electric disk brake according to claim 2, wherein the first member and the second member are engaged with each other with a gap in the rotation direction by an uneven engaging portion.

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