JP6679381B2 - Electric actuator - Google Patents

Description

  The present invention relates to an electric actuator.

  In recent years, electrification is progressing in order to save labor and reduce fuel consumption of vehicles and the like, and for example, a system for operating an automatic transmission, a brake, a steering wheel and the like of an automobile by the power of the 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 rotational movement of an electric motor into a linear movement is known.

  By the way, the ball screw mechanism has a 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 provided with a lock mechanism for preventing the ball screw from being driven against a reverse input from the operation target device side has been proposed.

  For example, in Patent Document 1, as shown in FIG. 15, a shaft 300 as a lock member that is detachable from a gear 400 that transmits a driving force from an electric motor 100 to a ball screw 200 is provided. By preventing the rotation of 400, the driving of the ball screw 200 is prevented.

Japanese Patent No. 5243018

  However, in the configuration described in Patent Document 1, since the shaft 300 is arranged at a position far from the ball screw 200 in the radial direction with respect to the rotation center of the gear 400, the shaft 300 and the ball screw 200 have an axial distance between them. There is a problem that the distance becomes long, the electric actuator becomes large, and the space required for installation becomes large.

  Therefore, an object of the present invention is to provide an electric actuator that can be downsized.

  As a technical means for achieving the above-mentioned object, the present invention includes 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 an output shaft of the drive unit, An electric actuator including a driving force transmission unit having a transmission gear mechanism that transmits a driving force from the drive unit to the motion conversion mechanism unit, and a lock mechanism unit that prevents the motion conversion mechanism unit from being driven. A first gear arranged on the side of the first gear and a second gear arranged on the side of the motion conversion mechanism, and the lock mechanism is on the opposite side of the first gear from the drive unit, It is characterized in that it is arranged on the motion converting mechanism side with respect to the center line of rotation of one gear.

  In this way, the lock mechanism unit is arranged on the side opposite to the drive unit with respect to the first gear and on the motion conversion mechanism unit side with respect to the rotation center line of the first gear, so that the lock mechanism unit Can be arranged close to the motion conversion mechanism section without considering interference with the drive section. As a result, the electric actuator can be downsized.

  As a technical means for achieving the above-mentioned object, the present invention provides a drive unit and a motion conversion mechanism unit for converting rotational motion from the drive unit into linear motion in an axial direction parallel to an output shaft of the drive unit. An electric actuator comprising: a driving force transmission unit having a transmission gear mechanism that transmits a driving force from the drive unit to the motion conversion mechanism unit; and a lock mechanism unit that prevents the motion conversion mechanism unit from being driven, wherein the transmission gear mechanism is , A first gear arranged on the drive unit side and a second gear arranged on the motion conversion mechanism unit side, and the lock mechanism unit has a motion conversion mechanism with respect to the first gear relative to the rotation center line thereof. It is characterized in that the rotation of the first gear is restricted by the engagement on the part side to prevent the motion converting mechanism part from being driven.

  In this way, by arranging the lock mechanism unit to engage with the first gear on the motion conversion mechanism unit side with respect to the rotation center line, the lock mechanism unit is arranged close to the motion conversion mechanism unit. It becomes easier to realize the miniaturization of the electric actuator.

  When engaging the lock mechanism portion with the first gear, it is preferable to form an engagement hole with which the lock mechanism portion engages on a side surface that intersects the axial direction of the first gear. In this case, since the lock mechanism portion does not engage with the teeth of the first gear, it is possible to avoid a load on the teeth due to the engagement and improve reliability.

  The lock mechanism portion includes a lock member that can be engaged with and disengaged from the engagement hole, a lock state in which the rotational movement of the rotary motor is converted into a linear movement to engage the lock member in the engagement hole, and a lock state in which the lock state is released. It is possible to have a slide screw device that is driven so as to be in at least one of the released state. By using the slide screw device for the lock mechanism portion, linear motion can be realized with a simple configuration having a small number of parts, and thus further miniaturization can be achieved.

  Further, since the actuator case has the rotation restricting portion that restricts the rotation of the linearly moving member of the slide screw device, it is not necessary to separately provide the rotation restricting member, which is advantageous for downsizing.

  For example, one of a slide screw nut and a slide screw shaft that configures a slide screw device is fixed to a lock member, and the other is fixed to an output shaft of a rotary motor, and the tip end side of the lock member is formed in a flat plate shape. By forming a through hole having a rectangular cross section into which the tip end side of the lock member is inserted in the case, the actuator case can be made to have a function as a rotation restricting portion. That is, in this case, since the tip end side of the lock member formed in a flat plate shape is inserted into the through hole formed in the rectangular cross section, the rotation of the lock member in the through hole is restricted, The rotation of the fixed slide screw nut or the slide screw shaft is restricted, and linear movement is possible.

  As described above, when the rotation is restricted between the lock member and the through hole, the tip end side of the lock member is preferably arranged coaxially with the output shaft of the rotary motor. With such a configuration, the position of the contact point (rotation restriction point) between the lock member and the through hole is closer to the radial direction from the rotation center line of the rotary motor, so that the moment received at the rotation restriction point is reduced. Therefore, the resistance to the linear movement of the lock member can be reduced. This improves the operability of the lock member and improves the reliability of the electric actuator.

  Further, the lock mechanism section has a spring for urging the lock member in a locked state, and the rotation motor unlocks the lock member against the urging force of the spring when the drive section is driven. You may make it drive so that it may switch to a state. In this case, the locked state can be maintained by the biasing force of the spring without supplying electric power to the rotary motor.

  Further, the rotation of the drive unit may be decelerated and transmitted from the first gear to the second gear. In this case, the rotational torque is increased and transmitted from the first gear to the second gear. Therefore, as described above, by setting the mating gear with which the lock mechanism portion engages as the first gear wheel having a small rotation torque, the lock mechanism portion is engaged at the time of engagement rather than engaging with the second gear wheel having a large rotation torque. Such a load can be reduced. Further, in this case, since the engagement partner of the lock mechanism unit is the first gear having a high rotation speed, the lock mechanism unit can be positioned more finely than the second gear after deceleration, and the motion conversion mechanism unit can be positioned. Positioning accuracy for stopping is improved.

  Further, the electric actuator may include a shaft case that accommodates a shaft part that linearly moves of the motion conversion mechanism part, and the shaft case may have a holder part that holds the lock mechanism part. In the electric actuator provided with such a shaft case, as described above, the lock mechanism unit is arranged close to the motion conversion mechanism unit, whereby the shaft case can be downsized.

  According to the present invention, an electric actuator suitable for miniaturization can be provided.

It is a longitudinal section of an electric actuator concerning one embodiment of the present invention. It is an external appearance perspective view of an electric actuator. It is an exploded perspective view of an electric actuator. It is the figure which looked at a motor case from the opening side. FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1. It is an exploded perspective view of a reduction mechanism part. It is an exploded perspective view of a shaft case and a lock mechanism part attached to this. FIG. 2 is a cross-sectional view taken along the line BB of FIG. It is the front view which looked at the bearing case from the left side in FIG. It is a perspective view showing the state where the tip part of the lock member projected from the penetration hole. FIG. 2 is a cross-sectional view taken along the line C-C of FIG. 1. It is a control block diagram of an electric actuator. It is a control block diagram of an electric actuator. 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 a conventional electric linear actuator.

  Hereinafter, the present invention will be described with reference to the accompanying drawings. In each of the drawings for explaining the present invention, components such as members and components having the same function or shape will be given the same reference numerals as far as possible to distinguish them from each other. Omit it.

  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. Is.

  As shown in FIG. 1, an electric actuator 1 according to the present embodiment includes a drive unit 2 that generates a drive 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, and a motion. The lock mechanism section 7 for preventing the driving of the conversion mechanism section 3 is a main component. The drive unit 2 is composed of a motor unit 8 and a reduction mechanism unit 9.

  Each part of the electric actuator 1 has a case, and the components are housed 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. Further, the driving force transmission unit 4 has a transmission gear case 29 that accommodates the transmission gear mechanism 28, and the motion conversion mechanism support unit 5 has 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 separable from each other with respect to the case. Further, the shaft case 50 is configured to be separable from the bearing case 41. Hereinafter, a detailed configuration of each unit configuring the electric actuator 1 will be described.

  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 has a bottomed cylindrical case main body 12 in which the drive motor 10 is housed, and a protrusion 13 protruding outward from a bottom 12 a of the case main body 12. The protrusion 13 is formed with a hole 13a that communicates with the internal space of the case body 12. The hole 13a is sealed by a resin sealing member 14 that covers the outer surface of the protrusion 13.

  When the drive motor 10 is inserted into the case body 12 through the opening 12d, the end surface of the drive motor 10 on the rear side in the insertion direction contacts the bottom portion 12a of the case body 12. Further, a fitting hole 12c is formed in the center of the bottom portion 12a, and a projection 10b on the rear side in the insertion direction of the drive motor 10 is fitted into the fitting hole 12c, so that the output projecting from the projection 10b is output. The rear end of the shaft 10a (the left end in FIG. 1) is prevented from interfering with the bottom 12a of the motor case 11. Further, the inner peripheral surface of the peripheral wall portion 12b of the case body 12 is tapered in diameter from the opening 12d side to the bottom portion 12a side, and when the drive motor 10 is inserted into the case body 12, the drive motor 10 is driven. The outer peripheral surface on the rear side in the insertion direction of the motor 10 is configured to contact the inner peripheral surface of the peripheral wall portion 12b. As described above, the driving motor 10 is supported by the contact with the inner peripheral surface of the case body 12 and the fitting hole 12c while being inserted into the case body 12.

  Further, as shown in FIG. 4 in which the motor case 11 is viewed from the opening 12d side, a pair of bus bars 15 for connecting the drive motor 10 to a power source is attached to the case body 12. 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 section 9 will be described.
As shown in FIG. 1, the reduction gear mechanism 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 including a plurality of gears and the like. The detailed configuration of the planetary gear 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. A motor adapter 19 as a motor mounting member can be mounted on the reduction gear case 17. The motor adapter 19 is a tubular member, and the projection 10d on the output side (right side in FIG. 1) of the drive motor 10 is inserted into and fitted to 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, and the motor adapter 19 is inserted into and attached to the fitting hole 17b from the drive motor 10 side.

  The reduction gear case 17 is configured to be engageable with the motor case 11 and a later-described transmission gear case 29 arranged on the opposite side thereof. Of the reduction gear case 17, a portion arranged on the motor case 11 side is fitted inside the opening 12d side of the motor case 11, and a portion arranged on the transmission gear case 29 side is fitted outside the transmission gear case 29. Further, the reduction gear case 17 is fastened to the drive motor 10 together with the motor adapter 19 by the bolts 21 (see FIGS. 3 and 6) while being fitted to the motor case 11. On the drive motor 10 side of the reduction gear case 17, with the reduction gear case 17 and the motor case 11 fitted together, the motor terminal 10c protruding from the drive motor 10 and the end 15a of the bus bar 15 crimped thereto. A recess 17c is formed to avoid interference with the. A mounting groove 17d for mounting the O-ring 20 is formed on the outer peripheral surface (fitting surface) of the reduction gear case 17 that fits with the inner peripheral surface of the motor case 11.

Next, the motion conversion mechanism section 3 will be described.
The motion conversion mechanism section 3 is composed of a ball screw 22. The ball screw 22 mainly includes a ball screw nut 23 as a rotating body, a ball screw shaft 24 as a shaft portion that linearly moves, a large number of balls 25 and a top 26 as a circulating member. Spiral grooves 23a and 24a 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 therein, whereby two rows of balls 25 are circulated.

  The ball screw nut 23 receives a 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 regulated by a pin 27 as a rotation regulating member provided at the rear end portion (right end portion in FIG. 1). Therefore, when the ball screw nut 23 rotates, the balls 25 circulate along the spiral grooves 23a and 24a and the top 26, and the ball screw shaft 24 advances and retracts in the axial direction. It should be noted that FIG. 1 shows a state in which the ball screw shaft 24 is arranged at an initial position in which the ball screw shaft 24 is most retracted to the right side of the drawing. Further, the ball screw shaft 24 is arranged parallel to the output shaft 10a of the drive motor 10, and the rotational movement from the drive motor 10 is converted into a linear movement in the axial direction parallel to the output shaft 10a by the ball screw shaft 24. To be converted. The forward end portion (the left end portion in FIG. 1) of the ball screw shaft 24 functions as an operation unit (actuator head) 6 for operating the operation target device.

Next, the driving force transmission section 4 will be described.
The driving force transmission unit 4 includes a transmission gear mechanism 28 that transmits a driving force from the drive 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. The main configuration. The transmission gear mechanism 28 has a drive-side drive gear 30 as a first gear and a driven-side driven gear 31 as a second gear that meshes with the drive gear 30.

  A gear boss 32 is press-fitted to the center of rotation of the drive gear 30. The drive gear 30 is rotatably supported by two rolling bearings 33 and 34 mounted on 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 moves forward and backward.

  The transmission gear case 29 has an accommodation 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 one rolling bearing 33 supporting the gear boss 32 is mounted on the inner peripheral surface of the insertion hole 29b. Are 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. In addition, a groove-shaped fitting recess 29f that fits into the bearing case 41 is formed on the surface of the transmission gear case 29 on the bearing case 41 side.

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

Subsequently, the motion conversion mechanism support portion 5 will be described.
The motion converting mechanism supporting portion 5 mainly includes a support bearing 40 that supports the ball screw 22 that is the motion converting mechanism portion 3 and a bearing case 41 that accommodates the support bearing 40. The support bearing 40 is a back-aligned double-row angular contact ball bearing whose main components are an outer ring 42, an inner ring 43, and a double-row ball 44 interposed therebetween.

  The support bearing 40 is housed 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, which are fixed to the outer peripheral surface of the ball screw nut 23, are axially controlled by the restriction protrusion 23b provided on the driven gear 31 side of the ball screw nut 23 and the restriction member 47 mounted on the support bearing 40 side. Movement is regulated. The regulating member 47 is composed of a pair of semi-circular members, and is mounted on the outer peripheral surface of the ball screw nut 23 in a state where these members are combined in an annular shape. Further, on the outer peripheral surface of the ball screw nut 23, a pressing collar 48 that holds the restricting member 47 and a retaining ring 49 that prevents 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 ridge 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, a gear boss accommodating portion 41b for accommodating a part of the gear boss 32 protruding from the transmission gear case 29 in a state where the bearing case 41 is fitted with the transmission gear case 29 is provided. There is. 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 (the right end side in FIG. 1) of the ball screw shaft 24 is provided with a bolt 51 (see FIG. 3). ) Can be concluded with. A mounting groove 50a 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 a pin 27 provided on the ball screw shaft 24 is 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 attached to both ends of the pin 27, and when the ball screw shaft 24 moves back and forth in the axial direction, the guide collars 53 move while rotating along the guide grooves 50b.

  As shown in FIG. 3, the motor case 11, the reduction gear case 17, the transmission gear case 29, and the bearing case 41 have bolt insertion holes 11a through which bolts 54 for assembling and fastening them are inserted around the radially outer sides of the respective cases. , 17e, 29i, 41d are provided. Further, through holes 29j and 41e for mounting the assembled electric actuator 1 at the installation location are provided in the outer periphery of both the transmission gear case 29 and the bearing case 41 in the radial direction.

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 of 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 accommodating recess 17a of the reduction gear case 17 is provided with the same number of engaging recesses 17f as the protrusions 55a (see FIG. 1). By incorporating the protrusion 55a of the ring gear 55 in phase with the engagement recess 17f of the reduction gear case 17, the ring gear 55 is housed while being prevented from rotating with respect to the reduction gear case 17.

  A sun gear 56 is arranged in the center of the ring gear 55, and the output shaft 10 a of the drive motor 10 is press-fitted into the sun gear 56. Further, the planet gears 57 are arranged between the ring gear 55 and the sun gear 56 so as to mesh with them. Each planet gear 57 is rotatably supported by a planet gear carrier 58 and a planet 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 speed reduction mechanism 18 configured as described above, when the drive motor 10 is rotationally driven, the sun gear 56 connected to the output shaft 10a of the drive motor 10 rotates, and the planet gears 57 rotate accordingly. While revolving, it revolves along the ring gear 55. The planetary gear carrier 58 is rotated by the revolution movement of the planetary gear 57. As a result, the rotation of the drive motor 10 is reduced and transmitted to the drive gear 30, and the rotational torque increases. By thus transmitting the driving force through the planetary gear speed reduction mechanism 18, the output of the ball screw shaft 24 can be increased, and the driving motor 10 can be downsized.

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

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

  The holder portion 66 is formed in a cylindrical shape with a bottom, and a cap 67 is attached to the side opposite to the bottom portion 66a. With the locking motor 64 inserted in the holder 66 and the cap 67 mounted, the locking motor 64 contacts the bottom 66 a of the holder 66 and the inner surface of the cap 67. Further, in this state, the protrusion 64b on the output side (left side in FIG. 1) of the locking motor 64 fits into the fitting hole 66c formed in the bottom 66a of the holder 66. Since 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 both formed in the same shape that is not a cylindrical shape, the locking motor 64 is disposed inside the peripheral wall portion 66b of the holder portion 66. By being inserted, the rotation of the lock motor 64 is restricted. In this way, the locking motor 64 is housed in the holder 66, so that the locking motor 64 is held by the holder 66 and the entire locking mechanism 7 is held. Further, a hole 67a for inserting a cable 68 connected to the motor terminal 64d of the locking motor 64 is formed in the cap 67 (see FIG. 8).

  Lock mechanism accommodating recesses 66d and 41f are formed in a portion of the shaft case 50 where the holder portion 66 is provided and in a portion of the bearing case 41 which faces the holder portion 66, respectively, and the lock mechanism accommodating recess portion 41f on the bearing case 41 side is penetrated. A hole 41g is formed. As shown in FIG. 1, in the state where the shaft case 50 is attached to the bearing case 41, the output shaft 64a of the lock motor 64 protruding from the holder 66 and the sliding screw shaft are provided in the lock mechanism housing recesses 66d and 41f. 62, the slide screw nut 61, the lock member fixing plate 63, the spring 65, and a part of the lock member 60 are accommodated, and the flat end of the lock member 60 is inserted into the through hole 41g. The through hole 41g is formed of a hole having a rectangular cross section and having substantially the same size and shape as the tip end side of the lock member 60 (see FIGS. 9 and 10). Further, in the state where the shaft case 50 is attached to the bearing case 41, the spring 65 is axially compressed between the bottom portion 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 biased in the forward direction (left side in FIG. 1).

  The drive gear 30 is arranged 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 the line C-C in FIG. 1, a plurality of engagement holes 30 a are provided in the circumferential direction of the drive gear 30. The rotation of the drive gear 30 is restricted by engaging the lock member 60 with one of the engagement holes 30a. An inclined surface 30b is formed at the entrance of each engagement hole 30a, and the lock member 60 is smoothly inserted into the engagement hole 30a along the inclined surface 30b.

  A lock sensor 69 for detecting the locked state is attached to the bearing case 41 (see FIG. 8). The lock sensor 69 has a contactor 69a composed of an elastic member such as a leaf spring, and when the lock member 60 advances and is engaged with the engagement hole 30a (in a locked state), the lock member 69a. When 60 pushes the contact 69a, it is detected that the locked state is achieved.

The operation of the lock mechanism unit 7 will be described below.
When power is not supplied to the lock motor 64, the lock member 60 is held at the advanced position by the spring 65, and the lock member 60 has a tip end engaged with the engagement hole 30 a of the drive gear 30. Is in a state. From this state, when power is supplied to the drive motor 10 to start driving the ball screw shaft 24, power is also supplied to the lock motor 64, and the lock motor 64 moves the lock member 60 backward. Drive to. As a result, the sliding screw shaft 62 rotates, while the sliding screw nut 61 is restricted from rotating by the insertion of the flat end of the lock member 60 into the through hole 41g having a rectangular cross section. Then, the slide screw nut 61 retracts against the biasing force of the spring 65, and the lock member 60 also retracts integrally with this. As a result, the tip of the lock member 60 is disengaged from the engagement hole 30a of the drive gear 30, and the locked state is released. Thus, while the ball screw shaft 24 is being driven, the lock member 60 is held in the retracted position, and the drive gear 30 is held in the unlocked state (unlocked state).

  After that, when the power supply to the drive motor 10 is cut off and the driving of the ball screw shaft 24 is stopped, the power supply to the lock motor 64 is also cut off. As a result, the driving force for keeping the lock member 60 retracted is not generated, so that the lock member 60 is pushed and moved in the forward direction by the spring 65. Then, the front end portion of the lock member 60 engages with the engagement hole 30a of the drive gear 30 to be in a locked state, and rotation of the drive gear 30 is restricted.

  In this way, 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 where it does not move back and forth. Accordingly, even if 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.

  In the present embodiment, the locking motor 64 is driven to move the locking member 60 backward, but conversely, the locking motor 64 may be driven to move the locking member 60 forward. Further, by rotating the lock motor 64 in the forward and reverse directions, it is possible to move the lock member 60 forward and backward.

  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 with a bolt 72 to a sensor case 76 provided on the outer peripheral surface between the motor case 11 and the boot cover 39. On the other hand, a permanent magnet 73 as a sensor target is attached to the outer peripheral surface of the portion of the ball screw shaft 24 covered by the boot 36 (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 line of magnetic force that changes accordingly, thereby grasping the axial position of the ball screw shaft 24. be able to.

Subsequently, 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 vehicle upper ECU.

  The drive motor 10 that has received the control signal starts rotational drive, and this drive force is transmitted to the ball screw shaft 24 via the planetary gear speed reduction mechanism 18, the drive gear 30, the driven gear 31, and the ball screw nut 23. The ball screw shaft 24 moves forward. As a result, 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. By thus feeding back the stroke value detected by the stroke sensor 70 and controlling the position of the ball screw shaft 24, when the electric actuator 1 of the present embodiment is applied to, for example, shift-by-wire, the shift position is changed. 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, the operation target device is provided with the pressure sensor 83. When the operation amount is input to the vehicle upper ECU, 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 rotational drive. As a result, the ball screw shaft 24 moves forward, and the operation target device arranged on the tip end side (actuator head side) of the ball screw shaft 24 is pressed.

  The operating 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. It In this way, 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 brake The liquid pressure can be reliably controlled.

  The configuration and operation of the electric actuator 1 of this embodiment are as described above. Hereinafter, regarding the electric actuator 1 of the present embodiment, constituent parts suitable for miniaturization will be described.

  As shown in FIG. 1, in the present embodiment, the lock mechanism portion 7 is arranged on the right side of the drawing with respect to the drive gear 30, that is, on the side opposite to the drive portion 2. In this way, by disposing the lock mechanism section 7 on the side opposite to the drive section 2, it is not necessary to consider the interference with the drive section 2 on the side on which the lock mechanism 7 is arranged. If the lock mechanism unit 7 is arranged on the same side as the drive unit 2, the lock mechanism unit 7 is axially arranged with respect to the drive unit 2 in order to avoid interference between the drive unit 2 and the lock mechanism unit 7. It must be displaced or displaced in the radial direction or the circumferential direction intersecting with this, which leads to an increase in the axial or radial size of the electric actuator 1. On the other hand, in the present embodiment, as shown in FIG. 1, the lock mechanism portion 7 is located directly above the motion conversion mechanism portion 3 as in the drive portion 2 (in the same phase position as the drive portion 2 in the circumferential direction of the ball screw 22). Therefore, the electric actuator 1 can be prevented from increasing in size. In addition, the weight balance is good.

  Further, in the present embodiment, the lock mechanism section 7 is arranged on the lower side of the figure with respect to the rotation center line X of the drive gear 30, that is, on the side of the motion conversion mechanism section 3 in the radial direction. In this way, by disposing the lock mechanism section 7 on the motion conversion mechanism section 3 side with respect to the rotation center line X of the drive gear 30, the lock mechanism section 7 is moved in the radial direction (linear motion) with respect to the motion conversion mechanism section 3. (Direction intersecting with the direction). Similarly, in the shaft case 50, the portion for housing the ball screw shaft 24 and the portion for housing the lock mechanism portion 7 (holder portion 66) can be arranged close to each other. As a result, the shaft case 50 is downsized, and the electric actuator 1 can be downsized in the vertical direction.

  In addition, the above-mentioned "the lock mechanism portion 7 is arranged on the motion conversion mechanism portion 3 side with respect to the rotation center line X of the drive gear 30" means the vertical dimension of the lock mechanism 7 (vertical dimension in FIG. 1). It means that more than half of them are arranged closer to the motion converting mechanism 3 than the rotation center line X of the drive gear 30. That is, in addition to the case where the entire lock mechanism portion 7 is arranged on the motion conversion mechanism portion 3 side with respect to the rotation center line X of the drive gear 30, a part of the lock mechanism 7 (a portion less than half the vertical dimension) is provided. The drive gear 30 may be arranged on the opposite side of the rotation center line X from the motion converting mechanism section 3.

  Further, as shown in FIG. 1, in the present embodiment, the lock mechanism portion 7 is configured to engage with the drive gear 30 on the motion conversion mechanism portion 3 side with respect to the rotation center line X thereof. With this configuration, the lock mechanism portion 7 can be easily arranged close to the motion conversion mechanism portion 3, and the electric actuator 1 can be easily downsized in the vertical direction.

  Further, in the present embodiment, the engagement hole 30a is formed in the side surface intersecting the axial direction of the drive gear 30, and the lock mechanism portion 7 is engaged with the engagement hole 30a. By doing so, since the lock mechanism portion 7 does not engage with the teeth of the drive gear 30, the load on the teeth due to the engagement can be avoided, and the reliability is improved.

  In the present embodiment, the rotation is transmitted from the drive gear 30 to the driven gear 31 at a constant speed, but the rotation may be reduced and transmitted from the drive gear 30 to the driven gear 31. In this case, the drive gear 30 has a higher rotation speed than the driven gear 31, but has a smaller rotation torque. Therefore, the load on the lock mechanism unit 7 at the time of engagement is reduced by using the drive gear 30 having a small rotation torque as the gear with which the lock mechanism unit 7 is engaged, instead of the driven gear 31 having a large rotation torque. be able to. Further, in this case, since the engagement partner of the lock mechanism portion 7 is the drive gear 30 having a high rotation speed, the lock gear portion 7 can be positioned more finely than the driven gear 31 after deceleration, and the motion conversion mechanism portion 3 Positioning accuracy for stopping is improved.

  Further, in this embodiment, a sliding screw device including a sliding screw nut 61 and a sliding screw shaft 62 is used as a mechanism for converting the rotational movement of the locking motor 64 into a linear movement. As described above, by using the slide screw device, linear motion can be realized with a simple structure having a small number of parts in a structure using a rotary motor as a drive source, and thus further miniaturization can be achieved.

  As described above, when the slide screw device is used, a configuration for restricting the rotation of the linearly moving member of the slide screw device is required. In the present embodiment, the bearing case 41 is provided with the through hole 41g having a rectangular cross section. By inserting the flat plate-shaped locking member 60 into the through hole 41g, the rotation of the member (sliding screw nut 61) that linearly moves of the sliding screw device is restricted. As described above, by making the bearing case 41, which is a part of the actuator case, function as the rotation restricting portion, it is not necessary to separately provide a member that restricts the rotation of the slide screw nut 61, and the size is reduced. Be advantageous to.

  As a configuration different from the present embodiment, a protrusion is provided on the outer peripheral surface of the slide screw nut 61, and the protrusion is brought into contact with the inner surface of the bearing case 41 to restrict the rotation of the slide screw nut 61. Good. However, when the location that restricts the rotation of the slide screw nut 61 is far from the output shaft 64a of the lock motor 64 in the radial direction, the moment that is received at the location that restricts the rotation increases, and the linear motion of the slide screw nut 61 increases. It is conceivable that the resistance to For this reason, it is desirable that the location where the rotation is restricted is located as close to the output shaft 64a of the locking motor 64 as possible in the radial direction. In this regard, in the present embodiment, the tip end side of the lock member 60 is arranged coaxially with the output shaft 64a of the lock motor 64 (see FIGS. 1 and 8), and therefore, in the radial direction of the output shaft 64a. The rotation can be restricted at a close position, and the resistance to the slide screw nut 61 can be reduced. This improves the operability of the lock member 60 and improves the reliability of the electric actuator.

FIG. 14 shows an electric actuator 1 according to another embodiment of the present invention.
The electric actuator 1 shown in FIG. 14 is different from the electric actuator 1 shown in FIG. 1 in that the reduction mechanism 9 is eliminated and the motor 8 and the driving force transmitter 4 are directly connected. In this case, since the output shaft 10a of the drive motor 10 does not have the reduction gear mechanism 9, the rolling bearing 33 on the side of the transmission gear case 29 that press fits into the gear boss 32 and supports the gear boss 32 is omitted. Further, since the mating member to be fitted to the motor adapter 19 to which the drive motor 10 is attached is changed from the reduction gear case 17 to the transmission gear case 29, the motor adapter 19 is changed to another shape that matches the mating shape of the mating member. Other configurations are similar to those of the embodiment shown in FIG. The electric actuator 1 of the embodiment shown in FIG. 14 differs from the electric actuator 1 of 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 passing through the speed reduction mechanism unit 9. The operation is basically controlled and operated in the same manner, and therefore the description of the control and operation will be omitted.

  In the electric actuator 1 shown in FIG. 14, as in the electric actuator 1 shown in FIG. 1, the lock mechanism portion 7 is on the side opposite to the drive portion 2 with respect to the drive gear 30, and the rotation center of the drive gear 30. By being arranged on the side of the motion converting mechanism 3 in the radial direction with respect to the line X, it is possible to reduce the size of the electric actuator 1. Further, since the lock mechanism portion 7 is configured to engage with the drive gear 30 on the side of the motion conversion mechanism portion 3 with respect to the rotation center line X thereof, it is easy to realize miniaturization.

  As described above, according to the present invention, the lock mechanism section 7 can be arranged close to the motion conversion mechanism section 3 without considering the interference with the drive section 2. Miniaturization can be realized. As a result, it becomes possible to reduce the size of the device or equipment in which the electric actuator is mounted. Therefore, in the configuration of the electric actuator according to the present invention, the electric actuator may be, for example, an electric parking brake mechanism for a vehicle including a motorcycle, an electric hydraulic brake mechanism, an electric shift switching mechanism, an electric power steering system, or a 2WD / 4WD electric motor. It is also suitable for developing a wide variety of products by creating a series that corresponds to applications and uses such as a switching mechanism and an electric shift switching mechanism for outboard motors (for marine propulsion machines).

  Although the embodiment of the present invention has been described above, the lock mechanism unit 7 is not limited to the one using the slide screw device, and may be one using the ball screw device.

  In the present embodiment, the configuration is adopted in which the sliding screw shaft 62 is rotated to linearly move the sliding screw nut 61, but conversely, the sliding screw nut 61 is rotated to linearly move the sliding screw shaft 62. May be. That is, by fixing the slide screw nut 61 to the output shaft 64a of the lock motor 64 and fixing the slide screw shaft 62 to the lock member 60, the slide screw nut 61 is rotated by the drive of the lock motor 64, and the slide screw nut 61 is rotated. It is possible to linearly move the shaft 62 and the lock member 60 integrally.

  Further, in the present embodiment, the lock motor (rotary motor) 64 is used as a drive source for retracting the lock member 60 in order to release the lock state. It may be used as a drive source for moving the member 60 forward, or as a drive source for switching the lock member 60 to both the locked state and the unlocked state (for moving the lock member 60 forward and backward). May be.

  The support bearing 40 that supports the motion converting mechanism section 3 is not limited to the configuration using the double row angular contact ball bearings, and may be a combination of a pair of single row angular contact ball bearings. Further, as the support bearing 40, in addition to the angular ball bearing, for example, another double row bearing using a deep groove ball bearing or the like can be applied.

  The motion conversion mechanism section 3 may be a slide screw device. However, from the viewpoint of reducing the rotating torque and downsizing the drive motor 10, the ball screw 22 is preferable.

  The present invention is not limited to the embodiments described above, and it is needless to say that the present invention can be implemented in various forms without departing from the gist of the present invention. It is indicated by the scope of the claims and further includes equivalent meanings to the claims and all modifications within the scope.

DESCRIPTION OF SYMBOLS 1 Electric actuator 2 Drive part 3 Motion conversion mechanism part 4 Driving force transmission part 5 Motion conversion mechanism support part 6 Operation part 7 Lock mechanism part 8 Motor part 9 Reduction mechanism part 10 Driving motor 10a Output shaft 28 Transmission gear mechanism 30 Drive gear (First gear)
30a Engagement hole 31 Driven gear (second gear)
50 Shaft Case 60 Lock Member 61 Sliding Screw Nut 62 Sliding Screw Shaft 64 Motor for Locking 65 Spring 66 Holder Part X Rotation Centerline of Drive Gear

Claims (10)

A drive unit, a motion conversion mechanism unit that converts rotational movement from the drive unit into a linear motion in an axial direction parallel to the output shaft of the drive unit, and a driving force is transmitted from the drive unit to the motion conversion mechanism unit. An electric actuator comprising: a driving force transmission unit having a transmission gear mechanism; and a lock mechanism unit that prevents driving of the motion conversion mechanism unit,
The transmission gear mechanism has a first gear arranged on the drive unit side and a second gear arranged on the motion conversion mechanism unit side,
The lock mechanism section is arranged on the side opposite to the drive section with respect to the first gear and on the motion conversion mechanism section side with respect to the rotation center line of the first gear ,
The electric actuator , wherein the lock mechanism portion moves back and forth in the axial direction of the first gear to engage and disengage from the first gear . A drive unit, a motion conversion mechanism unit that converts rotational movement from the drive unit into a linear motion in an axial direction parallel to the output shaft of the drive unit, and a driving force is transmitted from the drive unit to the motion conversion mechanism unit. An electric actuator comprising: a driving force transmission unit having a transmission gear mechanism; and a lock mechanism unit that prevents driving of the motion conversion mechanism unit,
The transmission gear mechanism has a first gear arranged on the drive unit side and a second gear arranged on the motion conversion mechanism unit side,
The lock mechanism section engages with the first gear on the motion conversion mechanism section side with respect to the rotation center line thereof, thereby restricting the rotation of the first gear and driving the motion conversion mechanism section. An electric actuator characterized by prevention.   The electric actuator according to claim 2, wherein an engagement hole with which the lock mechanism portion is engaged is formed on a side surface of the first gear which intersects the axial direction.   The lock mechanism portion includes a lock member that can be engaged with and disengaged from the engagement hole, and a locked state in which the rotational movement of the rotary motor is converted into a linear movement to engage the lock member with the engagement hole. The electric actuator according to claim 3, further comprising a slide screw device that is driven to be in at least one of an unlocked state and a unlocked state.   The electric actuator according to claim 4, wherein the actuator case has a rotation restricting portion that restricts rotation of a member of the sliding screw device that linearly moves when the rotary motor is rotationally driven. While fixing one of the slide screw nut and the slide screw shaft that configure the slide screw device to the lock member, the other is fixed to the output shaft of the rotary motor,
The tip end side of the lock member is formed in a flat plate shape,
The electric actuator according to claim 5, wherein the actuator case is formed with a through hole having a rectangular cross section into which the tip end side of the lock member is inserted.   The electric actuator according to claim 6, wherein a tip end side of the lock member is arranged coaxially with an output shaft of the rotary motor. The lock mechanism section has a spring for urging the lock member in the locked state,
The rotation motor is driven so as to switch the lock member to the unlocked state against the biasing force of the spring when the drive unit is driven. Electric actuator.   9. The electric actuator according to claim 2, wherein the rotation of the drive unit is decelerated and transmitted from the first gear to the second gear. A shaft case for accommodating a shaft part that linearly moves of the motion conversion mechanism part;
The electric actuator according to any one of claims 1 to 9, wherein the shaft case has a holder portion that holds the lock mechanism portion.

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