JP2018013183A - Electric actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric actuator capable of holding a stop position of a linear motion direction with good accuracy.SOLUTION: An electric actuator includes: a driving part 2; a motion conversion mechanism part 3 for converting a rotational motion from the driving part 2 into a linear motion in the axial direction in parallel with an output shaft 10a of the driving part 2; a driving force transmission part 4 having a transmission gear mechanism 28 for transmitting a driving force from the driving part 2 to the motion conversion mechanism part 3; and a lock mechanism part 7 for preventing the driving of the motion conversion mechanism part 3. The transmission gear mechanism 28 has a gear 30 in which a plurality of engagement holes are formed in the circumferential direction. The lock mechanism part 7 has a lock member 60 which can be engaged/disengaged to the engagement holes by advancing in the axial direction with respect to the gear 30. When the lock member 60 is advanced and is engaged with the engagement hole, the gear 30 is oscillated in one circumferential direction and the opposite direction from the direction by driving the driving part 2, and the circumferential direction phase alignment of the engagement hole is performed with respect to the lock member 60.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electric actuator.

  In recent years, electrification has progressed to save power and reduce fuel consumption of vehicles, etc., for example, a system for operating an automatic transmission, brakes, steering, etc. of an automobile with the power of an electric motor has been developed and put on the market. . As an actuator used for such an application, an electric linear actuator using a ball screw mechanism that converts a rotary motion of an electric motor into a linear motion is known.

  By the way, the ball screw mechanism has very good driving force transmission efficiency to the operation target device, but the ball screw shaft may move in the axial direction when an external force is input to the ball screw from the operation target device side. is there. In order to solve such a problem, conventionally, a device having a lock mechanism for preventing the ball screw from being driven due to reverse input from the operation target device side has been proposed.

  For example, Patent Document 1 proposes an electric linear actuator provided with a shaft that can be engaged and disengaged with respect to a gear as a lock mechanism. As shown in FIG. 21, the electric linear actuator described in Patent Document 1 includes an electric motor 100, a ball screw 200, a gear 400 that transmits a driving force from the electric motor 100 to the ball screw 200, and the like. The rotation of the gear 400 is prevented by advancing the 300 and passing the shaft 300 between the teeth of the gear 400.

  However, if the gear is stopped at an arbitrary position, the position between the teeth may be shifted from the position of the shaft depending on the stop position of the gear. In that case, there is a possibility that the shaft cannot pass between teeth and cannot be locked. In response to such a problem, Patent Document 1 proposes a method in which when the shaft 300 cannot pass between teeth, the protruding operation of the shaft 300 is repeated a plurality of times while feeding the motor for several pulses. That is, when the gap between the teeth and the position of the shaft 300 is deviated, the gear 400 is rotated excessively so that the shaft 300 is inserted between the teeth when the phase between the teeth and the shaft 300 coincide. .

Japanese Patent No. 5243018

  However, as in the method described in Patent Document 1, if the gear is excessively rotated for phase alignment at the time of locking, the ball screw is also driven accordingly. The stop position is affected. The effect on the stop position in the linear motion direction is due to the relative relationship between the amount of movement of the ball screw in the linear motion direction and the rotation angle of the gear, the pitch between teeth (between the engaging portions where the lock member engages). Although it varies depending on the size of the pitch), it is desirable that the amount of rotation of the gear for phase alignment is as small as possible from the viewpoint of maintaining the stop position in the linear motion direction at the target position.

  Accordingly, an object of the present invention is to provide an electric actuator that can accurately hold a stop position in a linear motion direction.

  As technical means for achieving the above-mentioned object, the present invention includes a drive unit, a motion conversion mechanism unit that converts rotational motion from the drive unit into linear motion in an axial direction parallel to the output shaft of the drive unit, An electric actuator including a driving force transmission unit having a transmission gear mechanism for transmitting a driving force from the driving unit to the motion conversion mechanism unit, and a lock mechanism unit for preventing the motion conversion mechanism unit from being driven. The lock mechanism portion has a lock member that moves forward and backward in the axial direction with respect to the gear and can be engaged with and disengaged from the engagement hole. When advancing and engaging with the engagement hole, driving the drive unit causes the gear to swing in one circumferential direction and the opposite direction to perform phase alignment of the engagement hole with the lock member in the circumferential direction. Features.

  Thus, even if the circumferential phase of the engagement hole and the lock member is shifted by performing the circumferential phase alignment of the engagement hole with respect to the lock member by swinging the gear, the lock member is engaged with the engagement hole. Can be reliably inserted. In addition, the phase can be adjusted with a smaller amount of rotation than when the gears are rotated in one direction to adjust the phase of the engagement holes. For this reason, there is little influence on the stop position of the electric actuator in the linear motion direction, and the position can be held with high accuracy.

  The electric actuator includes a lock sensor that detects an advancing / retreating position of the lock member, and the lock sensor moves the lock member forward while swinging the gear, and when the tip portion starts to be inserted into at least the engagement hole. The forward movement of the lock member may be stopped after a predetermined time has elapsed since the position of the lock member is detected and the lock sensor detects the position of the lock member.

  Thus, when the tip of the lock member starts to be inserted into at least the engagement hole, the position of the lock member is detected by the lock sensor, and the advancement of the lock member is stopped after a predetermined time has elapsed from the detected timing. Thus, the lock member can be reliably inserted into the engagement hole. That is, the timing of stopping the advancement of the lock member is counted at least after a predetermined time has elapsed since the lock member started to be inserted into the engagement hole, so that the lock member is not sufficiently inserted into the engagement hole. It can be managed so as not to become excessive or excessive.

  Further, it is desirable that the swinging width of the gear is set to be a half pitch of the interval between the engagement holes in one circumferential direction and the opposite direction.

  By setting such a swinging width of the gear, it is possible to reliably align the phase of the engagement hole with the lock member.

  Furthermore, when the lock member is retracted and removed from the engagement hole, the drive unit may be driven to swing the gear in one circumferential direction and the opposite direction.

  As described above, when the lock member is retracted and separated from the engagement hole, the gear is oscillated to prevent the lock member and the gear (the engagement surface of the engagement hole) from being caught, and the lock member is engaged. Since it becomes easy to remove from the joint hole, the locked state can be reliably released.

  According to the present invention, since the phase of the engagement hole and the lock member can be adjusted with a small amount of gear rotation, there is little influence on the stop position of the electric actuator in the linear motion direction, and the position can be accurately maintained. Can do.

It is a longitudinal cross-sectional view of the electric actuator which concerns on one Embodiment of this invention. It is an external appearance perspective view of an electric actuator. It is a disassembled perspective view of an electric actuator. It is the figure which looked at the motor case from the opening part side. It is the cross-sectional view seen from the AA line of FIG. It is a disassembled perspective view of a deceleration mechanism part. It is a disassembled perspective view of a shaft case and the lock mechanism part attached to this. It is the cross-sectional view seen from the BB line of FIG. It is the front view which looked at the bearing case from the left side in FIG. It is a perspective view which shows the state which the front-end | tip part of the lock member protruded from the through-hole. It is the cross-sectional view which looked at the CC line | wire of FIG. It is a control block diagram of an electric actuator. It is a control block diagram of an electric actuator. It is a figure for demonstrating the rocking | fluctuation width of a drive gear. It is a figure which compares and shows the rotation amount when rotating a drive gear to one direction, and the amount of rotation when rocking a drive gear and aligning a phase. It is a figure which shows an example of the control flow when performing a locking operation. It is a figure which shows an example of the control flow when performing unlocking operation | movement. It is a figure which shows another control flow of lock operation | movement. It is a figure for demonstrating the timing which detects the position of a locking member. It is a longitudinal cross-sectional view of the electric actuator which concerns on other embodiment of this invention. It is a longitudinal cross-sectional view of the conventional electric linear actuator.

  Hereinafter, the present invention will be described with reference to the accompanying drawings. In the drawings for explaining the present invention, components such as members and components having the same function or shape are denoted by the same reference numerals as much as possible, and once described, the description will be given. Omitted.

  1 is a longitudinal sectional view showing an assembled state of an electric actuator according to an embodiment of the present invention, FIG. 2 is an external perspective view showing the assembled state of the electric actuator, and FIG. 3 is an exploded perspective view of the electric actuator. It is.

  As shown in FIG. 1, the electric actuator 1 of the present embodiment includes a drive unit 2 that generates a driving force, a motion conversion mechanism unit 3 that converts a rotational motion from the drive unit 2 into a linear motion, and a drive unit 2. A driving force transmission unit 4 that transmits a driving force to the motion conversion mechanism unit 3; a motion conversion mechanism support unit 5 that supports the motion conversion mechanism unit 3; an operation unit 6 that outputs the motion of the motion conversion mechanism unit 3; The lock mechanism unit 7 that prevents the conversion mechanism unit 3 from being driven is mainly configured. The drive unit 2 includes a motor unit 8 and a speed reduction mechanism unit 9.

  Each part which comprises the said electric actuator 1 has a case, respectively, and the components are accommodated in each case. Specifically, the motor unit 8 has a motor case 11 that houses the drive motor 10, and the reduction mechanism unit 9 has a reduction gear case 17 that houses the reduction gear mechanism 16. The driving force transmission unit 4 includes a transmission gear case 29 that accommodates the transmission gear mechanism 28, and the motion conversion mechanism support unit 5 includes a bearing case 41 that accommodates the support bearing 40. The motor unit 8 and the speed reduction mechanism unit 9, the speed reduction mechanism unit 9 and the driving force transmission unit 4, and the driving force transmission unit 4 and the motion conversion mechanism support unit 5 are configured to be connected and separated together with the case. Further, the shaft case 50 is configured to be detachable from the bearing case 41. Hereinafter, the detailed structure of each part which comprises the electric actuator 1 is demonstrated.

  The motor unit 8 mainly includes a drive motor (DC motor) 10 that drives the motion conversion mechanism unit 3 and a motor case 11 that houses the drive motor 10. The motor case 11 includes a bottomed cylindrical case main body 12 in which the driving motor 10 is accommodated, and a protrusion 13 protruding outward from the bottom 12 a of the case main body 12. The protrusion 13 is formed with a hole 13 a that communicates with the internal space of the case body 12. The hole 13 a is sealed by a resin sealing member 14 that covers the outer surface of the protrusion 13.

  The drive motor 10 is inserted into the case main body 12 through the opening 12d thereof, and the end surface of the drive motor 10 in the insertion direction is in contact with the bottom 12a of the case main body 12. Further, a fitting hole 12c is formed at the center of the bottom portion 12a, and an output protruding from the protrusion 10b is obtained when the protrusion 10b on the back side in the insertion direction of the driving motor 10 is fitted into the fitting hole 12c. It is avoided that the rear end of the shaft 10a (the left end portion in FIG. 1) interferes with the bottom portion 12a of the motor case 11. Further, the inner peripheral surface of the peripheral wall portion 12b of the case main body 12 is tapered from the opening portion 12d side toward the bottom portion 12a side, and is driven when the driving motor 10 is inserted into the case main body 12. It is comprised so that the outer peripheral surface of the insertion direction back side of the motor 10 for a motor may contact the inner peripheral surface of the surrounding wall part 12b. Thus, the drive motor 10 is supported by the contact with the inner peripheral surface of the case main body 12 and the fitting hole 12c while being inserted into the case main body 12.

  As shown in FIG. 4 when the motor case 11 is viewed from the opening 12d side, the case main body 12 is attached with a pair of bus bars 15 for connecting the driving motor 10 to a power source. One end 15a of each bus bar 15 is caulked and connected to the motor terminal 10c, and the other end 15b is exposed to the outside from the case body 12 (see FIGS. 2 and 3). The end 15b of the bus bar 15 exposed to the outside is connected to the power source.

Next, the deceleration mechanism unit 9 will be described.
As shown in FIG. 1, the reduction mechanism unit 9 mainly includes a reduction gear mechanism 16 that reduces and outputs the driving force of the drive motor 10 and a reduction gear case 17 that houses the reduction gear mechanism 16. The reduction gear mechanism 16 includes a planetary gear reduction mechanism 18 that includes a plurality of gears and the like. The detailed configuration of the planetary gear speed reduction mechanism 18 will be described later.

  The reduction gear case 17 is provided with an accommodation recess 17a for accommodating the planetary gear reduction mechanism 18 from the side opposite to the drive motor 10 side. Further, the reduction gear case 17 is configured so that a motor adapter 19 as a motor attachment member can be attached. The motor adapter 19 is a cylindrical member, and a projection 10d on the output side (right side in FIG. 1) of the driving motor 10 is inserted into and fitted into the inner peripheral surface thereof. The reduction gear case 17 is formed with a fitting hole 17b into which the motor adapter 19 is fitted. The motor adapter 19 is inserted and attached to the fitting hole 17b from the drive motor 10 side.

  The reduction gear case 17 is configured to be able to be fitted to a motor case 11 and a transmission gear case 29 described later disposed on the opposite side of the motor case 11. Of the reduction gear case 17, a portion disposed on the motor case 11 side is fitted into the opening 12 d side of the motor case 11, and a portion disposed on the transmission gear case 29 side is fitted onto the transmission gear case 29. The reduction gear case 17 is fastened to the drive motor 10 by a bolt 21 (see FIGS. 3 and 6) together with the motor adapter 19 while being fitted to the motor case 11. On the side of the drive motor 10 of the reduction gear case 17, the motor terminal 10c protruding from the drive motor 10 and the end 15a of the bus bar 15 caulked to the drive motor 10 in a state where the reduction gear case 17 and the motor case 11 are fitted. A recess 17c is formed for avoiding interference. A mounting groove 17 d for mounting the O-ring 20 is formed on the outer peripheral surface (fitting surface) of the reduction gear case 17 that is fitted to the inner peripheral surface of the motor case 11.

Next, the motion conversion mechanism unit 3 will be described.
The motion conversion mechanism unit 3 includes a ball screw 22. The ball screw 22 mainly includes a ball screw nut 23 as a rotating body, a ball screw shaft 24 that is a linearly moving shaft portion, a large number of balls 25, and a top 26 as a circulating member. Helical grooves 23 a and 24 a are formed on the inner peripheral surface of the ball screw nut 23 and the outer peripheral surface of the ball screw shaft 24, respectively. A ball 25 is filled between the spiral grooves 23a and 24a, and a top 26 is incorporated, whereby two rows of balls 25 circulate.

  The ball screw nut 23 receives the driving force from the driving motor 10 and rotates in the forward direction or the reverse direction. On the other hand, the rotation of the ball screw shaft 24 is restricted by a pin 27 as a rotation restricting member provided at the rear end portion (the right end portion in FIG. 1). Therefore, when the ball screw nut 23 rotates, the ball 25 circulates along both the spiral grooves 23a and 24a and the top 26, and the ball screw shaft 24 advances and retreats in the axial direction. FIG. 1 shows a state in which the ball screw shaft 24 is disposed at the initial position where the ball screw shaft 24 is most retracted to the right in the drawing. The ball screw shaft 24 is arranged in parallel with the output shaft 10a of the drive motor 10, and the rotational motion from the drive motor 10 is changed by the ball screw shaft 24 into a linear motion in the axial direction parallel to the output shaft 10a. Converted. The forward end portion (left end portion in FIG. 1) of the ball screw shaft 24 functions as an operation portion (actuator head) 6 for operating the operation target device.

Next, the driving force transmission unit 4 will be described.
The driving force transmission unit 4 includes a transmission gear mechanism 28 that transmits driving force from the driving motor 10 of the driving unit 2 to the ball screw 22 that is the motion conversion mechanism unit 3, and a transmission gear case 29 that houses the transmission gear mechanism 28. Main structure. The transmission gear mechanism 28 has a drive gear 30 on the drive side as a first gear and a driven gear 31 on the driven side as a second gear meshing with the drive gear 30.

  A gear boss 32 is press-fitted into the rotation center of the drive gear 30. The drive gear 30 is rotatably supported by two rolling bearings 33 and 34 that are attached to both the transmission gear case 29 and a bearing case 41 described later via the gear boss 32. On the other hand, the driven gear 31 is press-fitted and fixed to the outer peripheral surface of the ball screw nut 23. When the driving force from the driving motor 10 is transmitted to the drive gear 30 via the planetary gear reduction mechanism 18, the driven gear 31 and the ball screw nut 23 rotate integrally, and the ball screw shaft 24 advances and retreats.

  The transmission gear case 29 has an accommodating recess 29a in which the drive gear 30 and the driven gear 31 are accommodated. Further, the transmission gear case 29 is formed with an insertion hole 29b for inserting the gear boss 32, and a bearing mounting surface 29c on which one rolling bearing 33 supporting the gear boss 32 is mounted on the inner peripheral surface of the insertion hole 29b. Is formed. Further, the transmission gear case 29 has an annular protrusion 29 d that fits with the inner peripheral surface of the reduction gear case 17. A mounting groove 29e for mounting the O-ring 35 is formed on the outer peripheral surface (fitting surface) of the annular protrusion 29d. Further, a groove-like fitting recess 29 f that fits with the bearing case 41 is formed on the surface of the transmission gear case 29 on the bearing case 41 side.

  The transmission gear case 29 has a cylindrical portion 29g that protrudes to the tip end side (left side in FIG. 1) of the ball screw shaft 24. The cylindrical portion 29g is a portion disposed so as to cover the periphery of the ball screw shaft 24 in a state where the driven gear 31 is accommodated in the transmission gear case 29 and the ball screw 22 is assembled thereto. A boot 36 that prevents foreign matter from entering the transmission gear case 29 is attached between the cylindrical portion 29 g and the ball screw shaft 24. The boot 36 includes a large-diameter end portion 36a, a small-diameter end portion 36b, and a bellows portion 36c that extends and contracts in the axial direction. The large-diameter end portion 36a is fastened and fixed to the mounting portion of the outer peripheral surface of the cylindrical portion 29g by the boot band 37, and the small-diameter end portion 36b is fastened and fixed to the mounting portion of the outer peripheral surface of the ball screw shaft 24 by the boot band 38. The cylindrical portion 29g is provided with a vent hole 29h for venting inside and outside when the boot 36 expands and contracts. Further, the motor case 11 is integrally provided with a boot cover 39 disposed around the boot 36.

Next, the motion conversion mechanism support unit 5 will be described.
The motion conversion mechanism support 5 mainly includes a support bearing 40 that supports the ball screw 22 that is the motion conversion mechanism 3 and a bearing case 41 that houses the support bearing 40. The support bearing 40 is constituted by a back-to-back double-row angular contact ball bearing in which an outer ring 42, an inner ring 43, and a double-row ball 44 interposed therebetween are main components.

  The support bearing 40 is accommodated in a sleeve 45 formed integrally with the bearing case 41 and is fixed by a retaining ring 46 attached to the inner peripheral surface of the sleeve 45. Further, the support bearing 40 is press-fitted and fixed to the outer peripheral surface of the ball screw nut 23 on the rear end side (right side in FIG. 1) of the ball screw shaft 24 with respect to the driven gear 31. The support bearing 40 and the driven gear 31 fixed to the outer peripheral surface of the ball screw nut 23 are axially moved by a restriction projection 23b provided on the driven gear 31 side of the ball screw nut 23 and a restriction member 47 mounted on the support bearing 40 side. Movement is restricted. The restricting member 47 is composed of a pair of semicircular arc members, and is mounted on the outer peripheral surface of the ball screw nut 23 in a state in which these are combined in an annular shape. Further, on the outer peripheral surface of the ball screw nut 23, a pressing collar 48 for holding the regulating member 47 and a retaining ring 49 for preventing the pressing collar 48 from falling off in the axial direction are mounted.

  On the transmission gear case 29 side of the bearing case 41, a protrusion 41a that fits into the fitting recess 29f of the transmission gear case 29 is provided. Further, on the transmission gear case 29 side of the bearing case 41, there is provided a gear boss accommodating portion 41 b in which a part of the gear boss 32 protruding from the transmission gear case 29 is accommodated when the bearing case 41 is fitted to the transmission gear case 29. Yes. A bearing mounting surface 41c for mounting the rolling bearing 34 that supports the gear boss 32 is formed on the inner peripheral surface of the gear boss housing portion 41b.

  On the side opposite to the transmission gear case 29 side of the bearing case 41, a bottomed cylindrical shaft case 50 that accommodates the rear end side (right end side in FIG. 1) of the ball screw shaft 24 is a bolt 51 (see FIG. 3). ) Can be fastened. A mounting groove 50 a for mounting the O-ring 52 is formed on the contact surface of the shaft case 50 with the bearing case 41. A guide groove 50b into which both ends of the pin 27 provided on the ball screw shaft 24 are inserted is formed on the inner peripheral surface of the shaft case 50 so as to extend in the axial direction. Guide collars 53 are rotatably mounted at both ends of the pin 27. When the ball screw shaft 24 advances and retracts in the axial direction, the guide collar 53 moves while rotating along the guide groove 50b.

As shown in FIG. 3, a bolt insertion hole 11a through which a bolt 54 for assembling and fastening the motor case 11, the reduction gear case 17, the transmission gear case 29, and the bearing case 41 is inserted in the outer periphery in the radial direction. , 17e, 29i, and 41d.
Further, through holes 29j and 41e for attaching the assembled electric actuator 1 to the installation location are provided in the radially outer periphery of both the transmission gear case 29 and the bearing case 41.

Here, the planetary gear reduction mechanism 18 will be described with reference to FIGS. 1, 5, and 6.
5 is a cross-sectional view taken along the line AA in FIG. 1, and FIG. 6 is an exploded perspective view of the planetary gear speed reduction mechanism 18.

  The planetary gear reduction mechanism 18 includes a ring gear 55, a sun gear 56, a plurality of planetary gears 57, a planetary gear carrier 58 (see FIG. 1), and a planetary gear holder 59 (see FIG. 1). The ring gear 55 has a plurality of protrusions 55a protruding in the axial direction, and the housing recess 17a of the reduction gear case 17 is provided with the same number of engagement recesses 17f as the protrusions 55a (see FIG. 1). By incorporating the convex portion 55a of the ring gear 55 in phase with the engaging concave portion 17f of the reduction gear case 17, the ring gear 55 is prevented from rotating with respect to the reduction gear case 17 and accommodated.

  A sun gear 56 is disposed in the center of the ring gear 55, and the output shaft 10 a of the driving motor 10 is press-fitted into the sun gear 56. Each planetary gear 57 is disposed between the ring gear 55 and the sun gear 56 so as to mesh with them. Each planetary gear 57 is rotatably supported by a planetary gear carrier 58 and a planetary gear holder 59. The planetary gear carrier 58 has a cylindrical portion 58a at the center thereof, and the cylindrical portion 58a is press-fitted between the outer peripheral surface of the gear boss 32 and the inner peripheral surface of the rolling bearing 33 (see FIG. 1). An annular collar 75 is mounted between the inner peripheral surface of the other rolling bearing 34 and the outer peripheral surface of the gear boss 32.

  In the planetary gear reduction mechanism 18 configured as described above, when the driving motor 10 is driven to rotate, the sun gear 56 connected to the output shaft 10a of the driving motor 10 rotates, and accordingly, each planetary gear 57 rotates. While revolving along the ring gear 55. The planetary gear carrier 58 is rotated by the revolving motion of the planetary gear 57. As a result, the rotation of the drive motor 10 is decelerated and transmitted to the drive gear 30 to increase the rotational torque. As described above, the driving force is transmitted through the planetary gear speed reduction mechanism 18 so that a large output of the ball screw shaft 24 can be obtained, and the driving motor 10 can be downsized.

  Subsequently, the lock mechanism unit 7 will be described with reference to FIGS. 1, 7, and 8. FIG. 7 is an exploded perspective view of the shaft case 50 and the lock mechanism portion 7 attached thereto, and FIG. 8 is a cross-sectional view taken along the line BB in FIG.

  The lock mechanism unit 7 mainly includes a lock member 60, a slide screw nut 61, a slide screw shaft 62, a lock member fixing plate 63, a lock motor (DC motor) 64, and a spring 65. In assembling the lock mechanism portion 7, first, the lock member 60 is fastened to the slide screw nut 61 with a bolt 84 (see FIG. 7) via the lock member fixing plate 63. Next, the locking motor 64 is accommodated in a holder portion 66 provided in the shaft case 50, and the sliding screw shaft 62 is attached to the output shaft 64 a of the locking motor 64 protruding from the holder portion 66. Then, the spring 65 is disposed on the outer periphery of the sliding screw shaft 62 and the sliding screw nut 61 to which the lock member 60 is attached is screwed onto the sliding screw shaft 62 and attached. In this way, the assembly of the lock mechanism unit 7 is completed.

  The holder part 66 is formed in a bottomed cylindrical shape, and a cap 67 is attached to the side opposite to the bottom part 66a. In a state where the locking motor 64 is inserted into the holder portion 66 and the cap 67 is attached, the locking motor 64 contacts the bottom 66 a of the holder portion 66 and the inner surface of the cap 67. Further, in this state, the projection 64 b on the output side (left side in FIG. 1) of the locking motor 64 is fitted into the fitting hole 66 c formed in the bottom 66 a of the holder portion 66. Since both the outer peripheral surface of the main body of the locking motor 64 and the inner peripheral surface of the peripheral wall portion 66b of the holder portion 66 are formed in the same shape that is not cylindrical, the locking motor 64 is placed in the peripheral wall portion 66b of the holder portion 66. By being inserted, the rotation of the locking motor 64 is restricted. As described above, when the lock motor 64 is accommodated in the holder portion 66, the lock motor 64 is held by the holder portion 66, and the entire lock mechanism portion 7 is held. The cap 67 is formed with a hole 67a through which a cable 68 connected to the motor terminal 64d of the locking motor 64 is inserted (see FIG. 8).

  Lock mechanism housing recesses 66d and 41f are respectively formed in the portion of the shaft case 50 where the holder portion 66 is provided and the portion of the bearing case 41 opposite thereto, and the lock mechanism housing recess 41f on the bearing case 41 side penetrates. A hole 41g is formed. As shown in FIG. 1, in a state where the shaft case 50 is attached to the bearing case 41, the output shaft 64a of the locking motor 64 protruding from the holder portion 66 and the sliding screw shaft are placed in the lock mechanism housing recesses 66d and 41f. 62, a sliding screw nut 61, a lock member fixing plate 63, a spring 65, and a part of the lock member 60 are accommodated, and a distal end side of the lock member 60 formed in a flat plate shape is inserted into the through hole 41g. The through hole 41g is configured by a hole having a rectangular section in the same size and shape as that of the distal end portion of the lock member 60 (see FIGS. 9 and 10). When the shaft case 50 is attached to the bearing case 41, the spring 65 is compressed in the axial direction between the bottom 66 a of the holder portion 66 and the lock member fixing plate 63, and the lock member 60 is compressed by the compressed spring 65. Is always urged in the forward direction (left side in FIG. 1).

  The drive gear 30 is disposed in the direction in which the lock member 60 moves forward, and the drive gear 30 is formed with an engagement hole 30a with which the tip of the lock member 60 can be engaged. As shown in FIG. 11, which is a cross-sectional view taken along line CC in FIG. 1, a plurality of engagement holes 30 a are provided in the circumferential direction of the drive gear 30. The lock member 60 is engaged with any one of these engagement holes 30 a, so that the rotation of the drive gear 30 is restricted. Moreover, the inclined surface 30b is formed in the entrance part of each engagement hole 30a, and the lock member 60 is smoothly inserted in the engagement hole 30a along this inclined surface 30b.

  The bearing case 41 is equipped with a lock sensor 69 for detecting the advance / retreat position of the lock member 60 in order to determine whether or not the lock is in a locked state (see FIG. 8). The lock sensor 69 has a contact 69a made of an elastic member such as a leaf spring. When the lock member 60 moves forward, the lock member 60 pushes the contact 69a, so that the position of the lock member 60 is changed. Detected.

Hereinafter, the operation of the lock mechanism unit 7 will be described.
When power is not supplied to the locking motor 64, the locking member 60 is held at the locked position advanced by the spring 65, and the distal end portion of the locking member 60 is engaged with the engagement hole 30 a of the drive gear 30. It is locked. From this state, when the lock motor 64 rotates in the reverse direction (rotates in the direction in which the lock member 60 is retracted), the slide screw shaft 62 rotates accordingly. At this time, since the rotation of the sliding screw nut 61 is restricted by the insertion of the flat tip end portion of the locking member 60 into the through hole 41g having a rectangular cross section, when the sliding screw shaft 62 rotates, the sliding screw nut 61 moves to the spring 65. The lock member 60 moves backward against the urging force, and the lock member 60 also moves backward. Thereby, the front-end | tip part of the lock member 60 will detach | leave from the engagement hole 30a of the drive gear 30, and it will be in the lock release state by which the lock member 60 was hold | maintained in the lock release position.

  After that, when the linear motion of the ball screw 22 of the electric actuator is stopped and the locked state is set again, the locking member 64 is moved forward by rotating the locking motor 64 forward. When the lock member 60 moves forward, the distal end portion of the lock member 60 is inserted into the engagement hole 30 a of the drive gear 30, and a lock state is established in which the rotation of the drive gear 30 is restricted by the engagement with the lock member 60. .

  As described above, the rotation of the drive gear 30 is restricted by the lock member 60, so that the ball screw shaft 24 is held in a state in which it does not advance and retreat. Thus, even when an external force is input from the operation target device side to the ball screw shaft 24 side, the position of the ball screw shaft 24 can be held at a predetermined position. Such a configuration is particularly suitable when the electric actuator is applied to an application that requires position holding. Further, as in the present embodiment, the engaging portion of the drive gear 30 with which the lock member 60 engages is not the tooth surface of the drive gear 30 but the engaging hole 30a provided on the side surface intersecting the axial direction. As a result, it is possible to avoid the occurrence of wear and deformation on the tooth surface, and to maintain good controllability of the electric actuator.

  In this embodiment, the locking motor 64 is driven to move the locking member 60 forward and backward. However, when the locking member 60 is advanced, the locking motor 64 is not driven and the biasing force of the spring 65 is driven. Only the locking member 60 may be advanced.

  The electric actuator 1 of this embodiment is equipped with a stroke sensor 70 for detecting the stroke of the ball screw shaft 24 (see FIGS. 2 and 3). The stroke sensor 70 is attached to a sensor base 71, and the sensor base 71 is fastened and fixed to a sensor case 76 provided on the outer peripheral surface between the motor case 11 and the boot cover 39 with bolts 72. On the other hand, a permanent magnet 73 as a sensor target is attached to the outer peripheral surface of the portion covered with the boot 36 of the ball screw shaft 24 (see FIG. 1). In the present embodiment, the permanent magnet 73 is attached to the ball screw shaft 24 via a cylindrical elastic member 74 separated at a part in the circumferential direction. When the ball screw shaft 24 advances and retracts, the position of the magnet 73 with respect to the stroke sensor 70 changes, and the stroke sensor 70 detects the direction of the lines of magnetic force that change accordingly, thereby grasping the axial position of the ball screw shaft 24. be able to.

Next, feedback control using the stroke sensor 70 will be described with reference to FIG.
As shown in FIG. 12, when the target value is sent to the control device 80, a control signal is sent from the controller 81 of the control device 80 to the drive motor 10. The target value is, for example, a stroke value calculated by the ECU based on the operation amount when the operation amount is input to the host ECU.

  Upon receiving the control signal, the driving motor 10 starts to rotate, and this driving force is transmitted to the ball screw shaft 24 via the planetary gear reduction mechanism 18, the drive gear 30, the driven gear 31, and the ball screw nut 23, The ball screw shaft 24 moves forward. Thereby, the operation target device arranged on the tip end side (actuator head side) of the ball screw shaft 24 is operated.

  At this time, the stroke value (axial position) of the ball screw shaft 24 is detected by the stroke sensor 70. The detection value detected by the stroke sensor 70 is sent to the comparison unit 82 of the control device 80, and the difference between the detection value and the target value is calculated. Then, the drive motor 10 is driven until the detected value matches the target value. Thus, when the stroke value detected by the stroke sensor 70 is fed back and the position of the ball screw shaft 24 is controlled, when the electric actuator 1 of this embodiment is applied to a shift-by-wire, for example, the shift position Can be reliably controlled.

Next, feedback control when the pressure sensor 83 is used instead of the stroke sensor 70 will be described with reference to FIG.
As shown in FIG. 13, in this case, a pressure sensor 83 is provided in the operation target device. When the operation amount is input to the ECU above the vehicle, the ECU calculates a required target value (pressure command value). When this target value is sent to the control device 80 and a control signal is sent from the controller 81 to the drive motor 10, the drive motor 10 starts to rotate. As a result, the ball screw shaft 24 moves forward, and the operation target device disposed on the tip end side (actuator head side) of the ball screw shaft 24 is pressurized.

  The operation pressure of the ball screw shaft 24 at this time is detected by the pressure sensor 83, and the position of the ball screw shaft 24 is feedback-controlled based on the detected value and the target value as in the case of using the stroke sensor 70. The As described above, the pressure value detected by the pressure sensor 83 is fed back and the position of the ball screw shaft 24 is controlled, so that when the electric actuator 1 of the present embodiment is applied to, for example, brake-by-wire, The fluid pressure can be reliably controlled.

  By the way, in the electric actuator according to the present embodiment, when the locking member 60 is brought into the locked state, if the circumferential phase between the engagement hole 30a and the lock member 60 is shifted, the lock member 60 is moved to the engagement hole 30a. Insertion may not be possible. In order to securely insert the lock member 60 into the engagement hole 30a, it is desirable to match the circumferential phase of the engagement hole 30a with the position of the lock member 60. However, in this embodiment, an inexpensive DC motor (brush motor) is used as the drive motor 10 and no means for detecting the rotation angle of the drive motor 10 is provided. Therefore, the phase of the engagement hole 30a cannot be adjusted. Therefore, the following measures are taken in the electric actuator according to the present invention.

  In the present embodiment, when the lock member 60 is inserted into the engagement hole 30a, the drive gear 30 provided with the engagement hole 30a is swung so that the engagement hole 30a is phased with respect to the lock member 60. I have to. That is, when the drive of the drive motor 10 is stopped and the linear motion of the ball screw 22 is finished, when the lock member 60 is advanced to the locked state, the drive motor 10 is alternately rotated in forward and reverse directions. Thus, the drive gear 30 is swung in one circumferential direction and the opposite direction. The swinging width W of the drive gear 30 at this time is set to a half pitch (1 / 2P) of the interval between the engagement holes 30a in one circumferential direction and the opposite direction, as shown in FIG. Has been. For example, when twelve engagement holes 30a are provided at intervals of 30 ° in the circumferential direction, the swing width W of the drive gear 30 is a half pitch (1 / 2P) of the interval between the engagement holes 30a. The total is 30 ° by 15 °.

  When the circumferential phase of the engagement hole 30a coincides with the position of the lock member 60 due to the swinging of the drive gear 30, the lock member 60 moves forward and the distal end thereof is inserted into the engagement hole 30a. Then, in a state where the distal end portion of the lock member 60 is completely inserted into the engagement hole 30a, the lock member 60 stops moving forward, and the drive gear 30 is also stopped, so that the lock member 60 is engaged. It is held in a locked state that can be engaged with the joint hole 30a.

  Thus, according to the present invention, even in a configuration using an inexpensive motor such as a DC motor (brush motor) that cannot detect the rotation angle, the drive gear 30 is swung to engage the engagement hole 30a with the lock member 60. By aligning the phases, the lock member 60 can be inserted into the engagement hole 30a. Thereby, the lock member 60 can be reliably inserted into the engagement hole 30a, and the reliability of the apparatus is improved.

  Moreover, in the method of phase adjustment by swinging the drive gear 30, the rotation amount for rotating the drive gear 30 for phase alignment of the engagement holes 30 a is suppressed to be equal to or less than a half pitch of the interval between the engagement holes 30 a. be able to. For this reason, it is possible to reduce the influence on the stop position of the ball screw 22 in the linear motion direction.

  For example, as shown in FIG. 15, when the engagement hole 30 a is displaced with respect to the lock member 60, if the drive gear 30 is rotated in one direction (clockwise in the figure) and phase adjustment is attempted, the lock member 60 The engagement hole 30a on the left side of the figure must be moved more than a half pitch to the right side of the figure. On the other hand, when the drive gear 30 is swung as in the present invention, the engagement hole 30a on the right side of the figure can be moved to the left side of the figure relative to the lock member 60. Phase alignment can be achieved by moving the engagement hole 30a to the left side of the drawing less than a half pitch. Thus, according to the present invention, the amount of rotation of the drive gear 30 for phase alignment can be reduced compared with the case where the drive gear 30 is rotated in one direction. The influence on the stop position can be reduced, and the stop position in the linear motion direction can be held with high accuracy.

FIG. 16 shows an example of a control flow when performing the locking operation.
Hereinafter, the locking operation will be described with reference to FIG.

First, the outline of the flow shown in FIG. 16 will be described.
As described above, in the present embodiment, when the lock member 60 is advanced, the drive gear 30 is swung so that the lock member 60 can be easily inserted into the engagement hole 30a. The member 60 may not be inserted into the engagement hole 30a. For this reason, in the flow shown in FIG. 16, the lock sensor 69 detects whether or not the lock member 60 has been normally inserted into the engagement hole 30a. If the lock sensor 69 is not turned ON even when the lock member 60 is moved forward (when the lock member 60 does not contact the lock sensor 69), the lock member 60 is normally inserted into the engagement hole 30a. If not, a retry operation is performed in which the lock member 60 is temporarily retracted and the lock member 60 is advanced again. Further, in order to measure the timing of shifting to the retry operation, the lock operation time is counted, and if the lock sensor 69 does not turn on even if the predetermined time continues, the operation shifts to the retry operation. Further, the number of retry operations is also counted, and if the lock sensor 69 is not turned ON even if the retry operation is performed a predetermined number of times, it is determined that the lock state will not be entered even if the retry operation is further performed. The lock operation is terminated.

Next, details of the flow shown in FIG. 16 will be described.
When there is a command to start the lock operation, first, the retry count is cleared and the count is returned to the initial state (0 times) (step 1). Further, the lock operation time is cleared and the count time is reset to the initial state (count time Return to (none) (step 2).

  Next, counting of the lock operation time is started (step 3), the swing of the drive gear 30 is started (step 4), the lock motor 64 is rotated forward, and the lock member 60 starts moving forward (step 5).

  Further, the lock sensor ON time count is cleared and the count time is returned to the initial state (no count time) (step 6). This lock sensor ON time is a time set to prevent erroneous detection due to switch chattering (ON / OFF swing) when the lock sensor 69 is turned ON. In the present embodiment, the lock sensor ON time is set to 0.6 seconds, and waiting for 0.6 seconds to elapse after the lock sensor 69 is turned on avoids erroneous detection due to chattering.

  Thereafter, it is confirmed whether or not the lock operation time has exceeded 3 seconds (step 7). If it has not exceeded 3 seconds, subsequently, it is confirmed whether or not the lock sensor 69 has been turned on (step 8). .

  As a result, when the lock sensor 69 is turned on, counting of the lock sensor ON time is started in order to avoid erroneous detection due to chattering (step 9). Then, it is confirmed whether or not the lock sensor ON time exceeds 0.6 seconds (step 10). If the lock sensor ON time is ON after 0.6 seconds, the lock member 60 is inserted into the engagement hole 30a. The swinging of the drive gear 30 is stopped (step 11), the forward movement of the lock member 60 is stopped (step 12), and the locking operation is finished.

  On the other hand, when the lock sensor 69 has not yet been turned ON in the above-described ON / OFF determination of the lock sensor 69 (step 8) and the lock operation time has exceeded 3 seconds (in the case of “Yes” in step 7). Assuming that the lock member 60 could not be inserted into the engagement hole 30a within a predetermined time, the drive gear 30 is temporarily stopped from swinging (step 13), and the operation proceeds to the retry operation. Here, since the retry operation is executed up to 3 times, it is confirmed whether the retry operation to be performed at the present time is not the fourth time (step 14), and if it is the third time, the retry operation is executed. To do.

  When the retry operation is performed, the lock motor 64 is reversely rotated to temporarily retract the lock member 60 (step 15), and the number of retries is counted (added once) (step 16). Then, the operation shifts to the lock operation time count clear operation (step 2) immediately after the start of the lock operation, and the subsequent operations are executed again. As a result, when the lock member 60 is inserted into the engagement hole 30a before the lock operation time exceeds 3 seconds (in the case of “Yes” in step 10), the swing of the drive gear 30 is stopped as described above. At the same time (step 11), the forward movement of the lock member 60 is stopped (step 12), and the locking operation is terminated.

  On the other hand, if the lock member 60 is not inserted into the engagement hole 30a even if the same retry operation is repeated three times (if “Yes” in step 14), the lock member 60 is not changed even if the retry operation is further performed. Is not inserted into the engagement hole 30a, the forward movement of the lock member 60 is stopped (step 17), and the operation is terminated.

Next, the unlocking operation will be described.
As described above, in the present invention, the drive gear 30 is swung during the locking operation to facilitate the engagement of the lock member 60 with the engagement hole 30a. It may be swung. The reason is that when a load is applied from the drive gear 30 to the lock member 60 in the locked state, the lock member 60 may not be easily detached from the engagement hole 30a. Therefore, in this embodiment, during the unlocking operation, the lock member 60 is moved backward while swinging the drive gear 30 in one circumferential direction and the opposite direction so that the locked state can be reliably released. Yes.

FIG. 17 is a diagram illustrating an example of a control flow when performing the unlocking operation.
In the unlocking operation of the present embodiment, when the lock member 60 is retracted, the drive gear 30 is swung so that the lock member 60 can be easily detached from the engagement hole 30a. Similarly, in the unlocking operation, the lock member 60 may not be detached from the engagement hole 30a due to some abnormality. Therefore, the lock sensor 69 detects whether or not the lock member 60 has been normally removed from the engagement hole 30a. If the lock sensor 69 is not turned off even if the lock member 60 is retracted (if the contact of the lock member 60 with the lock sensor 69 is not released), the lock member 60 is removed from the engagement hole 30a. Assuming that the lock member 60 has not been normally disengaged, a retry operation is performed in which the lock member 60 is once moved forward and the lock member 60 is moved backward again. Further, in order to measure the timing of shifting to the retry operation, the unlocking operation time is counted, and if the lock sensor 69 does not turn OFF even if the predetermined time continues, the operation shifts to the retry operation. Further, the number of retry operations is also counted, and if the lock sensor 69 is not turned off even if the retry operation is performed a predetermined number of times, it is determined that the lock release state is not obtained even if the retry operation is performed further. The unlocking operation is terminated at the time. Note that the flow shown in FIG. 17 is almost the same as the flow at the time of the locking operation shown in FIG. Since it is the same, detailed description is abbreviate | omitted.

FIG. 18 is a diagram showing another control flow of the locking operation.
In the flow shown in FIG. 18, when the locking operation is started, the drive gear 30 is swung and the lock member 60 is advanced. When the distal end portion of the lock member 60 starts to be inserted into the engagement hole 30 a, the lock member 60 comes into contact with the contact 69 a of the lock sensor 69, and its advance / retreat position is detected. Thereafter, when the predetermined time (in this example, 0.1 second) elapses, the forward movement of the lock member 60 is stopped. At the same time as the drive of the locking motor 64 is stopped, the swing of the drive gear 30 is also stopped. Thereby, the lock member 60 is completely inserted into the engagement hole 30a, and is held in a locked state in which the lock member 60 can be engaged with the engagement hole 30a.

  As described above, in the example shown in FIG. 18, the position of the lock member 60 is detected by the lock sensor 69 when at least the distal end portion of the lock member 60 starts to be inserted into the engagement hole 30a. The forward movement of the lock member 60 is stopped after a lapse of time. By controlling in this way, the lock member 60 can be reliably inserted into the engagement hole 30a. That is, the timing of stopping the advancement of the lock member 60 is counted at least after the lock member 60 starts to be inserted into the engagement hole 30a and after a predetermined time has elapsed, so that the lock member 60 with respect to the engagement hole 30a is stopped. It can be managed so that the insertion state does not become insufficient or excessive. In this example, erroneous detection due to chattering of the lock sensor 69 is ignored. Further, the predetermined time from when the position of the lock member 60 is detected to when the advance of the lock member 60 is stopped can be changed as appropriate. Further, as shown in FIG. 19, when the inclined surface 30b is provided at the entrance of the engagement hole 30a, the tip of the lock member 60 is inclined at the timing when the position of the lock member 60 is detected by the lock sensor 69. It may be the timing at which the insertion of the surface 30b is started or the timing at which the tip of the lock member 60 passes through the inclined surface 30b.

  Further, in order to minimize the displacement of the stop position in the linear motion direction accompanying the rotation of the drive gear 30 for phase alignment, that is, to minimize the amount of rotation of the drive gear 30 for phase alignment, It is also effective to set the pitch between 30a small. Here, when the lead of the ball screw 22 is L [mm] and the gear ratio between the drive gear 30 and the driven gear 31 (the number of teeth of the drive gear / the number of teeth of the driven gear) is r1 / r2, the rotation angle Y [ The relationship between [°] and the displacement X [mm] in the linear motion direction of the output shaft (ball screw shaft 24) of the electric actuator is expressed by the following equation (1).

  X = Y / 360 * (r1 / r2) * L (1)

For example, when L = 3 [mm] and r1 / r2 = 32/50, the above equation (1) becomes X = Y / 360 * (32/50) * 3 = 5.33Y * 10 ⁻³ . In this case, for example, if the displacement amount X in the linear motion direction of the output shaft of the electric actuator is in the range of 0.1 [mm] to 0.2 [mm], X = 0.1 in the above equation (1). By inputting [mm] and X = 0.2 [mm], the range of the rotation angle Y of the drive gear 30 corresponding to these values can be obtained. Specifically, X = 0.1 [mm] and X = 0.2 [mm] are input (0.1 = 5.33Y * 10 ⁻³ and 0.2 = 5.33Y * 10 ^{− 3} ), Y = 18.75 [°] and Y = 37.5 [°] are obtained, and therefore, the corresponding range of the rotation angle Y of the drive gear 30 is 18.75 [°] ≦ Y ≦ 37. 5 [°]. Therefore, the pitch of the engagement holes 30a is set so that the rotation amount (rotation angle Y) of the drive gear 30 for phase alignment is 18.75 [°] ≦ Y ≦ 37.5 [°]. By setting, the deviation of the stop position in the linear motion direction (the displacement amount X in the linear motion direction of the output shaft of the electric actuator) can be suppressed within the range of 0.1 [mm] to 0.2 [mm]. .

FIG. 20 shows an electric actuator 1 according to another embodiment of the present invention.
Compared with the electric actuator 1 shown in FIG. 1, the electric actuator 1 shown in FIG. 20 eliminates the speed reduction mechanism portion 9 and directly connects the motor portion 8 and the driving force transmission portion 4. In this case, since the output shaft 10a of the drive motor 10 does not have the speed reduction mechanism portion 9, the rolling bearing 33 on the transmission gear case 29 side that press-fits the gear boss 32 and supports the gear boss 32 is omitted. In addition, the motor adapter 19 to which the drive motor 10 is attached is replaced with another shape that matches the mating shape of the mating member because the mating mating member changes from the reduction gear case 17 to the transmission gear case 29. Other configurations are the same as those of the embodiment shown in FIG. The electric actuator 1 of the embodiment shown in FIG. 20 is the same as the embodiment shown in FIG. 1 except that the driving force from the driving motor 10 is directly transmitted to the driving force transmission unit 4 without going through the speed reduction mechanism unit 9. Since the operation is basically controlled in the same manner, a description of the control and operation is omitted.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and can of course be implemented in various forms without departing from the gist of the present invention. That is. For example, the motion conversion mechanism unit 3 is not limited to the ball screw 22 and may be a sliding screw device. However, the ball screw 22 is preferable from the viewpoint of reducing the rotational torque and reducing the size of the drive motor 10. In the above-described embodiment, the structure using the double-row angular ball bearing is illustrated as the support bearing 40 that supports the motion conversion mechanism unit 3. However, the configuration is not limited thereto, and a pair of single-row angular ball bearings are used. You may use it in combination. Further, as the support bearing 40, other than the angular ball bearing, for example, another double row bearing using a deep groove ball bearing or the like can be applied. The speed reduction mechanism 9 may be a speed reduction mechanism other than the planetary gear speed reduction mechanism 18. The electric actuator according to the present invention includes an electric parking brake mechanism for an automobile including a two-wheeled vehicle, an electric hydraulic brake mechanism, an electric shift switching mechanism, an electric power steering, a 2WD / 4WD electric switching mechanism, an outboard motor ( It can also be applied to an electric shift switching mechanism for ship propulsion devices.

DESCRIPTION OF SYMBOLS 1 Electric actuator 2 Drive part 3 Motion conversion mechanism part 4 Drive force transmission part 5 Motion conversion mechanism support part 7 Lock mechanism part 28 Transmission gear mechanism 30 Drive gear 30a Engagement hole 60 Lock member 69 Lock sensor

Claims (4)

A drive unit, a motion conversion mechanism unit that converts a rotational motion from the drive unit into a linear motion in an axial direction parallel to the output shaft of the drive unit, and a drive force is transmitted from the drive unit to the motion conversion mechanism unit An electric actuator comprising a driving force transmission part having a transmission gear mechanism, and a lock mechanism part for preventing the movement conversion mechanism part from being driven,
The transmission gear mechanism has a gear having a plurality of engagement holes formed in the circumferential direction,
The lock mechanism portion has a lock member that is movable in and out of the engagement hole in the axial direction with respect to the gear,
When the lock member is advanced and engaged with the engagement hole, the drive portion is driven to swing the gear in one of the circumferential directions and the opposite direction, and the engagement hole with respect to the lock member. An electric actuator characterized by performing phase alignment in the circumferential direction. A lock sensor for detecting an advance / retreat position of the lock member;
The lock sensor advances the lock member while swinging the gear, and detects the position of the lock member when the tip of the lock sensor starts to be inserted into at least the engagement hole,
The electric actuator according to claim 1, wherein the forward movement of the lock member is stopped after a predetermined time has elapsed since the lock sensor detects the position of the lock member.   The electric actuator according to claim 1 or 2, wherein the swinging width of the gear is set to be a half pitch of the interval between the engagement holes in one circumferential direction and the opposite direction.   4. The device according to claim 1, wherein when the lock member is retracted and removed from the engagement hole, the drive unit is driven to swing the gear in one circumferential direction and the opposite direction. 5. The electric actuator described in 1.

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