JP4640266B2 - Electric parking brake device - Google Patents

Description

  The present invention relates to a parking brake device employed in a vehicle, and in particular, with an electric motor as an input source, the parking brake is braked by forward rotation of the electric motor, and the parking brake is released by reverse rotation of the electric motor. The present invention relates to an electric parking brake device configured to be in a state.

As one of the electric parking brake devices of this type, an electric motor, a conversion mechanism that converts the rotational driving force of the electric motor into a linear driving force, and the linear driving force that is connected to the output portion of the conversion mechanism are parked. A cable that transmits to the brake, and a rotation drive transmission system between the electric motor and the conversion mechanism, allows rotation drive force transmission from the electric motor to the conversion mechanism, and allows rotation from the conversion mechanism to the electric motor. A one-way power transmission mechanism that restricts driving force transmission and an electric control device that controls rotational driving of the electric motor are provided, and the parking brake is released by the cable being pulled by the positive rotation driving of the electric motor. The parking state is changed to the braking state, and the cable is released by the reverse rotation driving of the electric motor. The rake is configured to be released from the braking state, and the braking state of the parking brake can be held by the one-way power transmission mechanism when the electric motor stops rotating forward (for example, a patent) Reference 1).
JP 2005-16600 A

  In the electric parking brake device disclosed in the above publication, the one-way power transmission mechanism (described as a release limiting mechanism D) is described as an input rotating unit (denoted as a protrusion 24a of the gear 24) that is rotationally driven by the electric motor. And an output rotating portion (described as a rotor 63) that is coaxially connected to the input rotating portion and is capable of relative rotation by a predetermined amount, and an outer periphery of the connecting portion between the output rotating portion and the input rotating portion. A non-rotatable fixed cylinder portion (denoted as a fixed ring 61) that surrounds the housing and is slidably accommodated in the fixed cylinder portion in the circumferential direction, and each end portion (62a, 62b) is the input When engaged with the rotating part and driven to rotate by the input rotating part, the frictional engagement force with the fixed cylinder part is reduced by the diameter reducing operation, and the rotation in the fixed cylinder part is allowed. Is engaged with the output rotation portion and is driven to rotate by the output rotation portion, the friction engagement force with the fixed cylinder portion is increased by the diameter expanding operation, and the rotation in the fixed cylinder portion is restricted. It is constituted by a clutch coil spring (described as a spring clutch 62).

  For this reason, when the cable is pulled by the forward rotation driving of the electric motor and the parking brake is changed from the released state to the braking state, in the one-way power transmission mechanism, the input rotating portion that is driven forward by the electric motor is connected to the clutch coil spring. Since the clutch coil spring is contracted by engaging with the pulling side end portion (62a), the frictional engagement force between the clutch coil spring and the fixed cylinder portion is reduced, and the clutch coil spring rotates within the fixed cylinder portion. Permissible. For this reason, at this time, the input rotating portion and the clutch coil spring are integrally driven to rotate forward. In addition, when the input rotating unit and the clutch coil spring are integrally driven to rotate positively, the output rotating unit is input when the input rotating unit is engaged with the output rotating unit via the pulling end of the clutch coil spring. Along with the rotating part and the clutch coil spring, it is positively rotated integrally.

  Further, when the braking state of the parking brake is held by the one-way power transmission mechanism when the electric motor stops rotating forward, the one-way power transmission mechanism receives the reverse rotation torque due to the tension acting on the cable and rotates. However, at this time, since the output rotating portion engages with the pulling side end portion (62a) of the clutch coil spring to increase the diameter of the clutch coil spring, the frictional engagement force between the clutch coil spring and the fixed cylinder portion is increased. As a result, the clutch coil spring is restricted from rotating in the fixed cylinder portion. For this reason, at this time, the output rotating portion is held by the reverse rotation of the output rotating portion being restricted by the clutch coil spring.

  In addition, when the cable is released by the reverse rotation drive of the electric motor and the parking brake is released from the braking state, the input rotation unit that is reversely driven by the electric motor in the one-way power transmission mechanism releases the clutch coil spring. Since the clutch coil spring is contracted by engaging the side end portion (62b), the frictional engagement force between the clutch coil spring and the fixed cylinder portion is reduced, and the clutch coil spring is allowed to rotate within the fixed cylinder portion. Is done. For this reason, at this time, the input rotating portion and the clutch coil spring are integrally driven in reverse rotation.

  By the way, when the input rotating portion and the clutch coil spring are integrally driven in reverse rotation by the reverse rotation driving of the electric motor, the output rotating portion does not reversely rotate due to the tension acting on the cable (the output rotating portion is in a self-locking state). In some cases, the input rotating portion is connected to the output rotating portion via the release-side end portion of the clutch coil spring while the tension-side end portion (62a) of the clutch coil spring is separated from the output rotating portion by a predetermined amount in the circumferential direction. And the output rotating unit is rotated in the reverse direction to release the self-locking state of the output rotating unit. For this reason, the output rotating part released from the self-locking state rapidly reversely rotates due to the tension acting on the cable, and collides with the tension side end part (62a) of the clutch coil spring to generate a contact sound.

The present invention has been made to reduce the above-described contact noise. In the electric parking brake device of the above-described type, the one-way power transmission mechanism includes an input rotating unit that is rotationally driven by the electric motor, An output rotation unit that is coaxially connected to the input rotation unit and is capable of relative rotation by a predetermined amount, a non-rotatable fixed cylinder that surrounds the outer periphery of the connection between the output rotation unit and the input rotation unit, and the fixed cylinder When the respective end portions engage with the input rotation portion and are rotationally driven by the input rotation portion, the diameter of the fixed cylinder portion is reduced by a diameter-reducing operation. When the frictional engagement force is reduced and rotation in the fixed cylinder portion is allowed, and each end portion engages with the output rotation portion and is driven to rotate by the output rotation portion, the fixed rotation is performed by expanding the diameter. Tube A clutch coil spring whose rotation in the fixed cylinder portion is restricted by being increased in friction engagement force, and provided between the input rotation portion and the output rotation portion within the clutch coil spring, and the input rotation portion when There driven reversely rotated by the electric motor, prior to the input rotary portion is rotated reversely the output rotating unit by engaging with the output rotary section via the release-side end portion of the clutch coil spring Further, the present invention is characterized in that a torque transmission member for transmitting a reverse rotation torque from the input rotation unit to the output rotation unit is provided.

In the electric parking brake device according to the present invention described above, when the input rotating portion and the clutch coil spring are integrally driven in reverse rotation by the reverse rotation driving of the electric motor, the output rotating portion does not reversely rotate due to the tension acting on the cable. case (when the output rotation section is a self-locking state), before the input rotation unit reversely rotates the output rotating unit by engaging with the output rotary section via the release-side end portion of the clutch coil spring The torque transmission member transmits the reverse rotation torque from the input rotation unit to the output rotation unit. Thus, before the input rotation unit reversely rotates the output rotating unit by engaging with the output rotary section via the release-side end portion of the clutch coil spring, to release the self-locking of the output rotary section, the output It is possible to reversely rotate the rotating part. For this reason, it is possible to reduce the circumferential clearance between the output rotating part that is released from self-locking and the tension side end of the clutch coil spring, compared to the case where no torque transmission member is provided. It is possible to reduce the contact noise when contacting the pulling side end of the clutch coil spring.

In carrying out the present invention, the torque transmission member is assembled to the input rotation part or the output rotation part, and the output rotation part or the engagement part between the input rotation part and the torque transmission member is: It is also possible for the engaging portion between the input rotating portion and the end of the clutch coil spring to be at a different position in the axial direction of the clutch coil spring. The torque transmission member may be an elastic body assembled to the input rotation unit or the output rotation unit. In this case, the input rotation unit is reversely driven by the electric motor, When the input rotating portion engages with the output rotating portion via the release side end portion of the clutch coil spring, the torque transmission member has a durability that the amount of elastic deformation of the torque transmitting member is not more than a set value. It is preferable for ensuring sufficiently. Further, the torque transmission member is engaged with the input rotating portion or the output rotating portion with a predetermined frictional force, and is assembled so as to be relatively movable in the circumferential direction at a predetermined torque or more. Is also possible.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an actuator of an electric parking brake device for an automobile embodying the present invention. This actuator decelerates and transmits a rotational driving force, which is an output of an electric motor 11, and the deceleration mechanism. A conversion mechanism B that converts the rotational driving force of the electric motor 11 transmitted via A into a linear driving force, and the linear driving force that is driven by the linear driving force converted by the conversion mechanism B and that outputs the linear driving force to two output units Between the electric motor 11 and the conversion mechanism B, a pair of cables 15 and 16 that are connected to the output portions 12a and 12b of the equalizer 12 and transmit a linear driving force to the parking brakes 13 and 14, respectively. The rotational driving force transmission system from the electric motor 11 to the conversion mechanism B is allowed to transmit the rotational driving force from the conversion mechanism B to the electric motor 11. Provided with a one-way power transmission mechanism C to regulate the rotation driving force transmission is provided with an electric control unit ECU for controlling the rotation drive of the electric motor 11 (see FIG. 5).

  As shown in FIG. 5, the operation of the electric motor 11 is controlled by the electric control unit ECU. The electric motor 11 is driven to rotate in the forward direction by operating the brake switch SW1. The release switch SW2 is operated to rotate in the reverse direction. The speed reduction mechanism A includes an input gear 21 and an output gear 22 and is incorporated in a casing 32 provided on one side of the housing 31. The input gear 21 is fixed to the output shaft 11a of the electric motor 11 and rotates integrally with the output shaft 11a. The output gear 22 meshes with the input gear 21, is fixed to the support shaft 23, and rotates integrally with the support shaft 23. As shown in FIGS. 1 to 4, the support shaft 23 is rotatably attached to a holder 33 fixed to the housing 31.

  As shown in FIG. 1, the conversion mechanism B has a screw shaft 41 connected coaxially and relatively rotatably to the support shaft 23 described above as an input element, and is screwed into the screw shaft 41 for assembly. The nut 42 is configured as an output element, and when the screw shaft 41 is rotationally driven in the forward direction, the nut 42 is moved from the release position (shown position) on the left side of FIG. 1 to the brake position on the right side of FIG. The nut 42 is moved in the axial direction of the screw shaft 41 toward the release position on the left side in FIG. 1 by being moved in the axial direction of the screw shaft 41 and being driven to rotate in the reverse direction. It has become.

  The screw shaft 41 is arranged with the moving direction of the cables 15 and 16 as the axial direction, and has two trapezoidal male screws (the number and shape of the male screws can be changed as appropriate). It is assembled so as to be immovable and rotatable in the axial direction. The nut 42 is connected to the equalizer 12 via a connecting pin 43, and supports the equalizer 12 so as to be swingable. The equalizer 12 distributes the linear driving force acting on the nut 42 equally to the two output portions, and is pivotally assembled to the nut 42 at the center thereof. Further, the equalizer 12 is rotatably connected to one end of the inner wire 15a in one cable 15 at an arm portion 12a which is one output portion, and is connected to the other end at an arm portion 12b which is the other output portion. The cable 16 is rotatably connected to one end of the inner wire 16a.

  One cable 15 is composed of an inner wire 15a and an outer tube 15b that covers the outer periphery other than both ends of the inner wire 15a. The other end of the inner wire 15a is an operating portion of one parking brake 13. It is connected to. The other cable 16 is composed of an inner wire 16a and an outer tube 16b that covers the outer periphery other than both ends of the inner wire 16a. The other end of the inner wire 16a is an operating portion of the other parking brake 14. It is connected to.

  As shown in FIGS. 1 to 4, the one-way power transmission mechanism C is formed integrally with the output end of the support shaft 23 and is rotated by the electric motor 11 via the speed reduction mechanism A. And an output rotating portion 41a that is integrally formed at the input end of the screw shaft 41 and is coaxially connected to the input rotating portion 23a and is capable of relative rotation by a predetermined amount, and an output that is formed integrally with the holder 33. A non-rotatable fixed cylinder portion 33a surrounding the outer periphery of the connecting portion between the rotation portion 41a and the input rotation portion 23a; a clutch coil spring 24 slidably accommodated in the fixed cylinder portion 33a in the circumferential direction; and a clutch coil A torque transmission member 25 provided between the input rotating portion 23a and the output rotating portion 41a in the spring 24 is configured.

  The clutch coil spring 24 is formed of a spring wire having a rectangular cross section, and a tensile side end 24a and a release side end 24b protrude toward the inner periphery, and the tension side end 24a and the release side end 24b. The input rotator 23a and the output rotator 41a can be engaged and disengaged. Further, when the end portions 24a and 24b are engaged with the input rotating portion 23a and are rotationally driven by the input rotating portion 23a, the clutch coil spring 24 is subjected to a diameter reducing operation so as to have a frictional engagement force with the fixed cylindrical portion 33a. When the end portions 24a and 24b are engaged with the output rotating portion 41a and are driven to rotate by the output rotating portion 41a, the diameter of the fixed cylinder is increased. The frictional engagement force with the portion 33a is increased so that rotation within the fixed cylinder portion 33a is restricted.

The torque transmission member 25 is formed of a thin spring plate material (elastic body), and is assembled at an intermediate portion to a groove 41a1 formed on the outer periphery of the output rotation portion 41a, and the tension side end of the input rotation portion 23a. And a release-side end 25b that can be disengaged from the release-side end of the input rotating portion 23a. The torque transmitting member 25, when the input rotation section 23a is driven reversely rotated by an electric motor 11, the input rotation portion 23a via the release-side end portion 24b of the clutch coil spring 24 is engaged with the output rotary section 41a Thus , the reverse rotation torque is set to be transmitted from the input rotation unit 23a to the output rotation unit 41a before the output rotation unit 41a is reversely driven .

  Further, in this torque transmission member 25, the maximum elastic deformation amount of the tension side end portion 25a (as shown in FIG. 6, the input rotating portion 23a is driven to rotate forward by the electric motor 11, and the input rotating portion 23a is connected to the clutch. The amount of elastic deformation when engaging the output rotating portion 41a via the tension-side end 24a of the coil spring 24 and the maximum amount of elastic deformation of the releasing-side end 25b (as shown in FIG. 9, the input rotating portion The amount of elastic deformation when the input rotating portion 23a is engaged with the output rotating portion 41a via the release-side end portion 24b of the clutch coil spring 24) is driven below the set value. The durability of the torque transmission member 25 is sufficiently secured.

  In the first embodiment configured as described above, when the actuator operates normally, when the brake switch SW1 is operated, the electric motor 11 is driven to rotate forward, and the screw shaft 41 of the conversion mechanism B is moved forward. Accordingly, the nut 42 and the equalizer 12 move in the axial direction of the screw shaft 41 from the left position (release position) in FIG. 1 toward the right position (braking position) in FIG. For this reason, the inner wires 15a and 16a of the cables 15 and 16 are pulled, and the parking brakes 13 and 14 are changed from the released state to the braked state.

  At this time, in the one-way power transmission mechanism C, the input rotating part 23a that is driven to rotate forward by the electric motor 11 is engaged with the pulling side end part 24a of the clutch coil spring 24 to reduce the diameter of the clutch coil spring 24. The frictional engagement force between the clutch coil spring 24 and the fixed cylinder portion 33a is reduced, and the clutch coil spring 24 is allowed to rotate within the fixed cylinder portion 33a. For this reason, at this time, the input rotating portion 23a and the clutch coil spring 24 are integrally driven to rotate forward. Further, when the input rotating portion 23a and the clutch coil spring 24 are integrally driven to rotate forward, the input rotating portion 23a is engaged with the output rotating portion 41a via the pulling side end portion 24a of the clutch coil spring 24. (Refer to FIG. 6) The output rotating portion 41a is integrally rotated forward together with the input rotating portion 23a and the clutch coil spring 24.

  When the braking state of the parking brakes 13 and 14 is held by the one-way power transmission mechanism C when the electric motor 11 is stopped in the normal rotation driving state, the output rotating portion 41a is connected to the cables 15 and 16 ( More specifically, the reverse rotation torque is received due to the tension acting on the inner wires 15a and 16a), and at this time, the output rotation portion 41a is engaged with the tension side end portion 24a of the clutch coil spring 42. In order to increase the diameter of the clutch coil spring 24, the frictional engagement force between the clutch coil spring 24 and the fixed cylindrical portion 33a increases, and the clutch coil spring 41a is restricted from rotating in the fixed cylindrical portion 33a. For this reason, at this time, the output rotating portion 41 a is held by the reverse rotation of the clutch coil spring 24 being restricted.

  Further, when the release switch SW2 is operated when the actuator operates normally, the electric motor 11 is driven to rotate in reverse, and the screw shaft 41 of the conversion mechanism B is rotated in reverse, whereby the nut 42 and the equalizer 12 are driven. Moves from the right position (braking position) in FIG. 1 to the left position (release position) in FIG. For this reason, the inner wires 15a and 16a of both the cables 15 and 16 are loosened, and both the parking brakes 13 and 14 are released from the braking state.

  At this time, in the one-way power transmission mechanism C, the input rotating portion 23a that is reversely driven by the electric motor 11 is engaged with the release-side end portion 24b of the clutch coil spring 24 to cause the clutch coil spring 24 to perform a diameter reducing operation ( 7), the frictional engagement force between the clutch coil spring 24 and the fixed cylinder portion 33a is reduced, and the clutch coil spring 24 is allowed to rotate within the fixed cylinder portion 33a. For this reason, at this time, the input rotating portion 23a and the clutch coil spring 24 are integrally driven in reverse rotation.

Incidentally, at this time, when the output rotating portion 41a does not reversely rotate due to the tension acting on both the cables 15 and 16 (when the output rotating portion 41a is in a self-locking state), the input rotating portion 23a is connected to the clutch coil spring 24. an output rotation portion 41a to engage with the output rotation section 41a through the releasing side end portion 24b before the reverse rotation drive, the input rotation section 23a engages with the releasing side end portion 25b of the torque transmitting member 25 (Refer to FIG. 8 and FIG. 9), the torque transmission member 25 transmits the reverse rotation torque from the input rotation unit 23a to the output rotation unit 41a.

Thus, before the input rotation section 23a reversely rotates the output rotation part 41a to engage the output rotation section 41a through the releasing side end portion 24b of the clutch coil spring 24, the self-locking of the output rotary section 41a Can be released and the output rotating portion 41a can be rotated in the reverse direction. For this reason, it is possible to reduce the circumferential clearance between the output rotating portion 41a that is released from the self-lock and the tension-side end portion 24a of the clutch coil spring 24, compared to the case where the torque transmission member 25 is not provided. It is possible to reduce the contact sound when the output rotating portion 41a contacts the pulling side end portion 24a of the clutch coil spring 24.

  When the input rotating portion 23a and the clutch coil spring 24 are driven in reverse rotation integrally, the output rotating portion 41a is not self-locking and can be rotated reversely by the tension acting on the cables 15 and 16. As the input rotating portion 23a and the clutch coil spring 24 are integrally driven to rotate reversely, the output rotating portion 41a rotates reversely due to the tension acting on the cables 15 and 16. Therefore, at this time, the state as shown in FIG. 7 is maintained, and there is no gap in the circumferential direction between the output rotating portion 41a and the pulling side end portion 24a of the clutch coil spring 24, and the output rotating portion 41a There is no contact with the pulling side end 24a of the spring 24.

In the first embodiment described above, the torque transmission member 25 is assembled to the output rotating portion 41a. However, as in the second embodiment shown in FIGS. It is also possible to carry out by being assembled to the input rotating unit 23a. The torque transmission member 125 of the second embodiment is engaged with the input rotating portion 23a with a predetermined frictional force and is assembled so as to be relatively movable in the circumferential direction at a predetermined torque or more. It functions in the same manner as the torque transmission member 25 of the embodiment (that is, when the input rotating portion 23a is driven in reverse rotation by the electric motor 11, the input rotating portion 23a is output via the release side end portion 24b of the clutch coil spring 24. ahead to engage the rotating portion 41a reversely rotates the output rotation section 41a, transmits the reverse rotational torque from the input rotation unit 23a to the output rotating unit 41a).

  Since the configuration other than the torque transmission member 125 is the same as that of the first embodiment, the same reference numerals are given and the description thereof is omitted. The operation of the second embodiment is substantially the same as the operation of the first embodiment described above, and can be easily understood from the description of the operation of the first embodiment and the description of FIGS. Therefore, the explanation is omitted. In addition, FIGS. 11-14 for operation | movement description in 2nd Embodiment respond | correspond to FIGS. 6-9 of above-described 1st Embodiment, respectively.

  In the second embodiment described above, the torque transmission member 125 is assembled to the input rotating portion 23a. However, the torque transmission member corresponding to the torque transmitting member 125 can be assembled to the output rotating portion 41a. It is. In these embodiments (the modified embodiment of the second embodiment), the torque transmission member does not necessarily need to be formed of an elastic body.

  In the first embodiment described above, the torque transmission member 25 is formed of a thin spring plate material (elastic body). However, the torque transmission member 225 of the third embodiment shown in FIG. 15 or the first embodiment shown in FIG. As in the torque transmission member 325 of the fourth embodiment, it can be formed by a rubber elastic body.

  The torque transmission member 225 of the third embodiment shown in FIG. 15 is integrally assembled with the input rotation part 23a, and is disengaged from the tension side end part of the output rotation part 41a at the tension side end part 225a. It is possible to engage and disengage from the release side end of the output rotating portion 41a at the release side end 225b. It should be noted that the tension side end portion 225a and the release side end portion 225b are provided with a hole 225a1 for setting the maximum elastic deformation amount of the tension side end portion 225a and the maximum elastic deformation amount of the release side end portion 225b to a set value or less, respectively. 225b1 is provided, and the durability of the torque transmission member 225 is sufficiently ensured.

  The torque transmission member 325 of the fourth embodiment shown in FIG. 16 is integrally assembled with the output rotation part 41a, and is disengaged from the tension side end part of the input rotation part 23a at the tension side end part 325a. It is possible to engage and disengage from the release side end of the input rotation part 23a at the release side end 325b. It should be noted that the pull-side end 325a and the release-side end 325b include a hole 325a1 for setting the maximum elastic deformation amount of the pull-side end portion 325a and the maximum elastic deformation amount of the release-side end portion 325b to a set value or less, respectively. 325b1 is provided, and the durability of the torque transmission member 325 is sufficiently ensured.

1 is a partially broken plan view showing a first embodiment of an electric parking brake device according to the present invention. It is an expanded sectional view along line 2-2 in FIG. It is the figure which rotated 90 degree | times clockwise the expanded sectional view along the 3-3 line of FIG. FIG. 4 is an enlarged cross-sectional view taken along line 4-4 of FIG. 2 and rotated clockwise by 135 degrees. It is a block diagram which shows the relationship between the electric motor shown in FIG. 1, the electric control apparatus which is not shown in FIG. 1, a brake switch, and a release switch. FIG. 5 is an operation explanatory diagram of the one-way power transmission mechanism shown in FIGS. 1 to 4 in a state in which an input rotation unit is driven to rotate forward by an electric motor. FIG. 5 is an operation explanatory diagram of the one-way power transmission mechanism shown in FIGS. 1 to 4 in a state in which an input rotating portion is driven to rotate reversely by an electric motor and engaged with a release side end portion of a clutch coil spring. FIG. 5 is an operation explanatory view of the one-way power transmission mechanism shown in FIGS. 1 to 4 in a state where an input rotation unit is driven to rotate in reverse by an electric motor and engaged with a release-side end portion of a torque transmission member. In the one-way power transmission mechanism shown in FIG. 1 to FIG. 4, the input rotating part is driven in reverse rotation by the electric motor and engaged with the release side end of the output rotating part via the release side end of the clutch coil spring. It is an operation explanatory view. It is sectional drawing equivalent to FIG. 2 of 2nd Embodiment. FIG. 11 is an operation explanatory diagram of the one-way power transmission mechanism illustrated in FIG. 10 in a state where the input rotation unit is driven to rotate forward by an electric motor. FIG. 11 is an operation explanatory diagram of the one-way power transmission mechanism shown in FIG. 10 in a state in which an input rotating portion is driven to rotate reversely by an electric motor and engaged with a release-side end portion of a clutch coil spring. FIG. 11 is an operation explanatory diagram of the one-way power transmission mechanism illustrated in FIG. 10 in a state in which the input rotation unit is reversely driven by the electric motor and engaged with the release-side end portion of the torque transmission member. In the one-way power transmission mechanism shown in FIG. 10, the operation of the input rotating part is driven reversely by the electric motor and engaged with the releasing end of the output rotating part via the releasing end of the clutch coil spring. It is. It is sectional drawing equivalent to FIG. 2 of 3rd Embodiment. It is sectional drawing equivalent to FIG. 2 of 4th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Electric motor, 13, 14 ... Parking brake, 15, 16 ... Cable, 23 ... Support shaft, 23a ... Input rotation part, 24 ... Clutch coil spring, 24a ... Pull-side end part, 24b ... Release-side end part, 25 ... torque transmitting member, 25a ... tension side end, 25b ... release side end, 31 ... housing, 32 ... casing, 33 ... holder, 33a ... fixed cylinder part, 41 ... screw shaft, 41a ... output rotating part, 42 ... Nut, B ... Conversion mechanism, C ... One-way power transmission mechanism, ECU ... Electric control device

Claims (4)

An electric motor, a conversion mechanism that converts the rotational driving force of the electric motor into a linear driving force, a cable that is connected to an output portion of the conversion mechanism and transmits the linear driving force to a parking brake, the electric motor, and the A one-way power transmission mechanism that is provided in a rotational drive transmission system between the conversion mechanisms and that allows rotational drive force transmission from the electric motor to the conversion mechanism and restricts rotational drive force transmission from the conversion mechanism to the electric motor. And an electric control device for controlling the rotational drive of the electric motor, wherein the cable is pulled by the forward rotation drive of the electric motor to change the parking brake from the released state to the braked state, and the reverse of the electric motor. The cable is released by rotation driving and the parking brake is released from the braking state. Rutotomoni, in the electric parking brake device configured to be held by the one-way power transmission mechanism during normal rotation driving stop of the braking state of the parking brake the electric motor,
The one-way power transmission mechanism includes an input rotation unit that is rotationally driven by the electric motor, an output rotation unit that is coaxially connected to the input rotation unit and is capable of relative rotation by a predetermined amount, the output rotation unit, and the A non-rotatable fixed cylinder part surrounding the outer periphery of the coupling part of the input rotation part, and is accommodated in the fixed cylinder part so as to be slidable in the circumferential direction, and each end engages with the input rotation part and When rotationally driven by the input rotating part, the frictional engagement force with the fixed cylinder part is reduced by performing a diameter reducing operation, allowing rotation in the fixed cylinder part, and each end part is engaged with the output rotating part. In addition, a clutch coil spring whose friction engagement force with the fixed cylinder part is increased by a diameter expanding operation when the output rotation part is rotationally driven, and the rotation in the fixed cylinder part is restricted, and the clutch Coils Provided between the input rotation unit and the output rotation unit in the ring, and when the input rotation unit is driven to rotate in reverse by the electric motor, the input rotation unit is configured to move the release side end of the clutch coil spring. characterized in that before the reverse rotation drives the output rotating unit by engaging with the output rotary section via, and a torque transmitting member for transmitting a reverse rotational torque to the output rotary unit from the input rotation section Electric parking brake device. 2. The electric parking brake device according to claim 1, wherein the torque transmission member is assembled to the input rotation unit or the output rotation unit, and the relationship between the output rotation unit or the input rotation unit and the torque transmission member. The electric parking brake device according to claim 1, wherein the joint portion is located at a different position in an axial direction of the clutch coil spring with respect to an engaging portion between the input rotating portion and an end portion of the clutch coil spring. 3. The electric parking brake device according to claim 1 , wherein the torque transmitting member is an elastic body assembled to the input rotating portion or the output rotating portion. 4. The electric parking brake device according to claim 3 , wherein the input rotation unit is reversely driven by the electric motor, and the input rotation unit is engaged with the output rotation unit via a release-side end portion of the clutch coil spring. In the electric parking brake device, the elastic deformation amount of the torque transmitting member is equal to or less than a set value.

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