JP2013038846A - Electric linear actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric linear actuator which has reduced weight by reducing the number of components and simplifying a structure and enables cost reduction by reducing the number of assembly man-hours.SOLUTION: A deceleration mechanism 6 and a ball screw mechanism 8 are attached to a bracket 2, and a cup-shaped cover 21 is detachably fitted to the bracket 2. The cup-shaped cover 21 is formed of thermoplastic synthetic resin by injection molding, and has a radially projecting lock portion 22 located at an opening end. An annular groove 23 is formed in the bracket. The lock portion 22 of the cover 21 is locked on the annular groove 23, and the cover 21 is fitted to the annular groove 23 while elastically deformed. At least the ball screw mechanism 8 is sealed from the outside.

Description

  The present invention relates to an electric linear actuator having a ball screw mechanism used in a drive unit of a general industrial electric motor or automobile, and more specifically, a rotational input from an electric motor is applied to a ball in a transmission or a parking brake of the automobile. The present invention relates to an electric linear actuator that converts a linear motion of a drive shaft through a screw mechanism.

  In electric linear actuators used for various drive units, a gear mechanism such as a trapezoidal screw or a rack and pinion is generally used as a mechanism for converting the rotational movement of the electric motor into a linear linear movement. Since these conversion mechanisms involve a sliding contact portion, the power loss is large, and it is necessary to increase the size of the electric motor and increase the power consumption. Therefore, a ball screw mechanism has been adopted as a more efficient actuator.

  As a conventional electric linear actuator, for example, a ball screw shaft constituting a ball screw can be driven to rotate by an electric motor supported by a housing, and an output member coupled to a nut by rotating the ball screw shaft. Can be displaced in the axial direction. Since the ball screw mechanism has very low friction and the ball screw shaft easily rotates due to the thrust load acting on the output member side, it is necessary to hold the position of the output member when the electric motor is stopped.

  Therefore, for example, a brake means is provided in the electric motor, or a low-efficiency thing such as a worm gear is provided as a transmission means. As a typical example, an electric linear actuator as shown in FIG. It has been known. The electric linear actuator 50 includes an actuator main body 52 including a ball screw 51 that converts rotational motion into linear motion, a gear reduction mechanism 54 that transmits the rotational motion of the electric motor 53 to the actuator main body 52, and a gear reduction mechanism 54. A position holding mechanism 56 is provided that engages with the first gear 55 constituting the position and holds the position of the actuator main body 52.

  The ball screw 51 has a spiral thread groove 57a formed on the outer peripheral surface, and is externally fitted to the screw shaft 57 as an output shaft and the screw shaft 57, and a spiral thread groove 58a is formed on the inner peripheral surface. A nut 58 and a large number of balls 59 accommodated in a rolling path formed by opposing screw grooves 57a and 58a are provided.

  The actuator main body 52 includes a nut 58 rotatably supported on the inner periphery of the housing 60 via a pair of ball bearings 61 and 62, and a screw shaft 57 that cannot rotate relative to the housing 60. It is supported movably in the direction. The nut 58 is rotationally driven via the gear reduction mechanism 54, whereby the screw shaft 57 is converted into a linear motion.

  The gear reduction mechanism 54 is engaged with a first gear 55 formed of a small-diameter spur gear fixed to the motor shaft 53 a of the electric motor 53, and a large diameter integrally formed on the outer periphery of the nut 58. And a second gear 63 composed of a spur gear.

  The position holding mechanism 56 is a shaft 64 as a lock member that is detachably attached to the first gear 55, and driving means that drives the shaft 64 in a direction to be engaged with and disengaged from the first gear 55. The solenoid 65 is provided. The shaft 64 has a rod shape and is linearly driven by a solenoid 65, and its tip end portion is engaged with and disengaged from the receiving portion 66. In this way, by controlling the solenoid 65, the shaft 64 engages with the first gear 55 and is prevented from rotating. Therefore, even when a vibration load is applied, the engagement surface can be stably prevented from slipping. The position of the screw shaft 57 of the actuator body 52 can be held (see, for example, Patent Document 1).

JP 2009-156416 A

  However, in such a conventional electric linear actuator 50, the drive parts such as the ball screw 51 are incorporated in the housing 60 in order to prevent the intrusion of muddy water and oil from the outside and the scattering of grease filled in the inside depending on the use location. Has been. In particular, in the electric linear actuator 50 including the gear reduction mechanism 54 constituted by two or more gears of the first gear 55 and the second gear 63 of this type, the structure of the housing 60 is divided into two parts from the viewpoint of assembly. It has become.

  In this case, there are problems such as an increase in the number of parts due to the fastening of the housing 60, an increase in the number of assembly steps, an increase in the mass of the housing 60, etc.

  The present invention has been made in view of the problems of the prior art, and provides an electric linear actuator that reduces the number of parts, reduces the weight by a simple structure, and reduces the number of assembly steps to reduce the cost. The purpose is to do.

  In order to achieve such an object, the invention according to claim 1 of the present invention is a disc-shaped bracket, an electric motor attached to the bracket, and the rotational force of the electric motor transmitted through the motor shaft. And a ball screw mechanism that converts the rotational movement of the electric motor into a linear movement in the axial direction of the drive shaft via the reduction mechanism, and the ball screw mechanism is a support bearing mounted on the bracket. And a nut that is supported so as not to move in the axial direction and has a spiral thread groove formed on the inner periphery, and is inserted into the nut via a number of balls and is coaxial with the drive shaft. And a screw shaft that is formed on the outer periphery of the screw shaft so as to correspond to the screw groove of the nut and is supported so as to be non-rotatable and axially movable with respect to the bracket. Linear In Chueta, wherein with speed reduction mechanism and the ball screw mechanism is assembled to the bracket, cup-shaped cover to the bracket is capable mounted removably, the ball screw mechanism is sealed from the outside by the cover.

  As described above, the disk-shaped bracket, the electric motor attached to the bracket, the reduction mechanism that transmits the rotational force of the electric motor via the motor shaft, and the rotation of the electric motor via the reduction mechanism. A ball screw mechanism that converts the motion into a linear motion in the axial direction of the drive shaft, and this ball screw mechanism is supported by a support bearing mounted on the bracket so as to be rotatable and not movable in the axial direction. A nut having a spiral thread groove formed on the circumference, and a helical screw that is inserted into the nut via a large number of balls and is coaxially integrated with the drive shaft and corresponds to the thread groove of the nut on the outer periphery. In an electric linear actuator that is formed with a screw shaft that is formed with a groove and is supported so that it cannot rotate with respect to the bracket and can move in the axial direction, the speed reduction mechanism and the ball screw mechanism are assembled to the bracket. At the same time, a cup-shaped cover is detachably attached to the bracket, and the ball screw mechanism is sealed from the outside by the cover, so that leakage of grease filled in the ball screw mechanism to the outside, This can reliably prevent muddy water and oil from entering from the outside, and the cost is increased by increasing the number of parts and assembly man-hours by fastening the housing, compared to the conventional case where the drive parts are mounted in a two-part housing. Alternatively, it is possible to provide an electric linear actuator that can suppress an increase in the mass of the housing, reduce the number of parts, reduce the weight by a simple structure, reduce the number of assembly steps, and reduce the cost.

  Further, as in the second aspect of the invention, the electric motor may be sealed from the outside by the cover.

  Preferably, as in the invention described in claim 3, the cover is formed by injection molding of a thermoplastic synthetic resin, and includes an engaging end projecting in the radial direction at the opening end portion, and the bracket is annular. If the groove is formed, and the locking portion of the cover is locked in the annular groove, and the cover is mounted in an elastically deformed state, the cover can be mounted on the bracket with one touch, and the number of parts can be increased. An increase in cost due to an increase in assembly man-hours or an increase in the mass of the housing can be suppressed, the number of parts can be reduced, the weight of the simple structure can be reduced, and the number of man-hours for assembly can be reduced to reduce costs.

  Further, as in the invention described in claim 4, if at least three locking portions are formed in the circumferential direction, a desired pulling strength can be ensured, and the detachability of the cover is improved.

  According to a fifth aspect of the present invention, the bracket has a first mounting hole that houses the input gear that constitutes the speed reduction mechanism and the nut that constitutes the ball screw mechanism. If a hole is provided and the support bearing is mounted in the second mounting hole, the weight and size can be reduced.

  Further, as in the invention described in claim 6, both end surfaces of the bracket are formed flat, one end surface becomes a mounting surface of the mating mounting part, and is joined in close contact with the other end surface. If the cover is attached, the structure is simplified and the weight can be reduced.

  Further, as in the invention described in claim 7, if the bracket is made of an aluminum alloy, the weight can be reduced.

  Further, as in the invention according to claim 8, if the assembly insertion direction of the electric motor and the ball screw mechanism is set in the same direction, the assembly work can be simplified and the assembly workability is improved. be able to.

  As in the ninth aspect of the invention, an output gear constituting the speed reduction mechanism is integrally fixed to the outer periphery of the nut via a key, and a flange is formed at one end of the nut. If the support bearing is fitted and fixed with the flange and the output gear sandwiched between the output gear and the nut, the nut is supported with respect to the bracket by a single support bearing so as to be rotatable and non-movable in the axial direction. can do.

  Preferably, as in the invention according to claim 10, if the position of the flange of the nut is set in the same direction as the input gear and the sub-assembly of the electric motor, the assembly insertion direction of the electric motor and the ball screw mechanism Can be set in the same direction, and the assembling work can be simplified.

  Moreover, if the said support bearing is comprised by the four-point contact ball bearing like invention of Claim 11, it can restrict the play of an axial direction as much as possible.

  An electric linear actuator according to the present invention includes a disc-shaped bracket, an electric motor attached to the bracket, a reduction mechanism that transmits the rotational force of the electric motor via a motor shaft, and the reduction mechanism. A ball screw mechanism for converting the rotational motion of the electric motor into a linear motion in the axial direction of the drive shaft, and the ball screw mechanism can be rotated via a support bearing attached to the bracket and moved in the axial direction. A nut that is unsupported and has a spiral thread groove formed on the inner periphery, and is inserted into the nut through a number of balls, and is integrated coaxially with the drive shaft and screwed on the outer periphery of the nut. An electric linear actuator comprising a screw shaft formed with a spiral screw groove corresponding to the groove and supported so as not to rotate with respect to the bracket and to be movable in the axial direction. The reduction mechanism and the ball screw mechanism are assembled to the bracket, and a cup-shaped cover is detachably attached to the bracket, and the ball screw mechanism is sealed from the outside by the cover. Compared to the conventional case where the grease filled inside can be surely prevented from leaking to the outside and muddy water or oil from entering from the outside, and the drive parts are mounted on the housing divided into two parts The increase in the number of parts and the increase in assembly man-hours due to fastening can be suppressed, or the increase in the mass of the housing can be suppressed, reducing the number of parts, reducing the weight of the simple structure, and reducing the assembly man-hours. The illustrated electric linear actuator can be provided.

(A) is a longitudinal cross-sectional view which shows 1st Embodiment of the electric linear actuator which concerns on this invention, (b) is a principal part enlarged view which shows the mounting part of the resin cover of (a). It is a longitudinal cross-sectional view which shows the ball screw mechanism of FIG. (A) is a longitudinal cross-sectional view which shows 2nd Embodiment of the electric linear actuator which concerns on this invention, (b) is a principal part enlarged view which shows the mounting part of the resin cover of (a). It is a longitudinal cross-sectional view which shows the conventional electric linear actuator.

  A disc-shaped bracket made of aluminum alloy, an electric motor attached to the bracket, a reduction mechanism that transmits the rotational force of the electric motor via a motor shaft, and rotation of the electric motor via the reduction mechanism A ball screw mechanism that converts the motion into a linear motion in the axial direction of the drive shaft, and this ball screw mechanism is supported by a support bearing mounted on the bracket so as to be rotatable and not movable in the axial direction. A nut having a spiral thread groove formed on the inner periphery, and a spiral corresponding to the thread groove of the nut on the outer periphery, which is inserted into the nut through a large number of balls and is coaxially integrated with the drive shaft. In the electric linear actuator comprising a screw shaft that is formed so as to be non-rotatable and axially movable with respect to the bracket, the speed reduction mechanism and the ball screw A mechanism is assembled to the bracket, and a cup-shaped cover is detachably attached to the bracket. The cover is formed by injection molding with a thermoplastic synthetic resin, and a locking portion that protrudes in the radial direction at the opening end. An annular groove is formed in the bracket, and a locking portion of the cover is locked in the annular groove, the cover is mounted in an elastically deformed state, and at least the ball screw mechanism is sealed from the outside. Yes.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1A is a longitudinal sectional view showing a first embodiment of an electric linear actuator according to the present invention, FIG. 1B is an enlarged view of a main part showing a mounting portion of the resin cover of FIG. FIG. 2 is a longitudinal sectional view showing the ball screw mechanism of FIG. 1.

  As shown in FIG. 1A, the electric linear actuator 1 includes a bracket 2 made of an aluminum alloy such as A6063TE or ADC12, an electric motor 3 attached to the bracket 2, and a motor shaft 3a of the electric motor 3. A speed reduction mechanism 6 comprising an input gear 4 attached to the input gear 4 and an output gear 5 meshing with the input gear 4, and the rotational motion of the electric motor 3 through the speed reduction mechanism 6 is linearly moved in the axial direction of the drive shaft 7. A ball screw mechanism 8 for converting into

  The bracket 2 is formed in a disc shape, and includes a first mounting hole 2 a that houses the input gear 4 and a second mounting hole 2 b that houses the nut 12 constituting the ball screw mechanism 8. The electric motor 3 is attached to the first attachment hole 2a, and a support bearing 28 for rotatably supporting the nut 12 is attached to the second attachment hole 2b. Both end surfaces of the bracket 2 are formed flat, and one end surface 2c is a mounting surface of the mating mounting component 9, and is joined in close contact.

  The motor shaft 3a of the electric motor 3 is fitted with an input gear 3 made of a spur gear at its end so as not to be relatively rotatable by press fitting, and meshed with an output gear 5 made of a spur gear. The output gear 5 is integrally fixed to a nut 12 constituting a ball screw mechanism 8 described later via a key 13.

  The drive shaft 7 is configured integrally with a screw shaft 10 that constitutes a ball screw mechanism 8 and is supported by an oil seal 11 mounted on a mating attachment component 9 so that the drive shaft 7 cannot rotate but can move in the axial direction. The rotational torque of the electric motor 3 is decelerated from the input gear 4 by the output gear 5 and transmitted to the nut 12, and is converted into a linear motion of the drive shaft 7 by the ball screw mechanism 8.

  As shown in an enlarged view in FIG. 2, the ball screw mechanism 8 includes a screw shaft 10 and a nut 12 that is externally inserted to the screw shaft 10 via a ball 14. The screw shaft 10 has a spiral thread groove 10a formed on the outer periphery. On the other hand, the nut 12 is extrapolated to the screw shaft 10, and a helical screw groove 12 a corresponding to the screw groove 10 a of the screw shaft 10 is formed on the inner periphery. A large number of balls 14 are rollably accommodated between the screw grooves 10a and 12a. The nut 12 is formed with a keyway 15 on the outer periphery, and the output gear 5 is integrally fixed via a key 13 locked in the keyway 15 and is positioned in the axial direction by a retaining ring 16.

  Further, a flange 17 is formed at one end of the nut 12, and a support bearing 18 is fitted and fixed in a state of being sandwiched between the flange 17 and the output gear 5. The support bearing 18 is mounted in the second mounting hole 2 b of the bracket 2 and is positioned and fixed in the axial direction by a retaining ring 19. The nut 12 is supported via the support bearing 18 so as to be rotatable and non-movable in the axial direction with respect to the bracket 2 (see FIG. 1A). The support bearing 18 may be a sealed deep groove ball bearing, but here, a four-point contact ball bearing that can regulate axial play as much as possible is preferable. Reference numeral 20 denotes a piece member that constitutes a circulation member by connecting the screw grooves 12a of the nut 12, and the piece member 20 allows an infinite circulation of a large number of balls 14.

  The cross-sectional shape of each thread groove 10a, 12a may be a circular arc shape or a Gothic arc shape, but here, it has a Gothic arc shape that allows a large contact angle with the ball 14 and a small axial clearance. Is formed. Thereby, the rigidity with respect to an axial load becomes high and generation | occurrence | production of a vibration can be suppressed.

  The nut 12 is made of case-hardened steel such as SCM415 or SCM420, and the surface thereof is hardened in the range of 55 to 62HRC by vacuum carburizing and quenching. Thereby, the buffing etc. for the scale removal after the heat treatment can be omitted, and the cost can be reduced. On the other hand, the screw shaft 10 is made of medium carbon steel such as S55C or case-hardened steel such as SCM415 or SCM420, and its surface is hardened in the range of 55 to 62 HRC by induction hardening or carburizing hardening.

  Moreover, in this embodiment, the assembly insertion direction of the electric motor 3 and the ball screw mechanism 8 is made the same direction by aligning the positions of the input gear 4, the subassembly of the electric motor 3, and the flange 17 of the nut 12 in the same direction. Assembling work can be simplified and assembling workability can be improved.

  Here, as shown in FIG. 1A, the drive parts such as the ball screw mechanism 8 and the electric motor 3 are all assembled to the bracket 2, and these drive parts are sealed with a resin cover 21. The resin cover 21 is formed by injection molding with a thermoplastic synthetic resin such as PA (polyamide) 66 filled with a predetermined amount of a fibrous reinforcing material such as GF (glass fiber), and protrudes toward the inner diameter side at the opening end. The locking portion 22 is provided. In addition, this latching | locking part 22 should just be formed at least 3 not only in the cyclic | annular protrusion formed in a perimeter but the circumferential direction. Thereby, while being able to ensure desired extraction strength, the detachability of the resin cover 21 improves.

  As shown in FIG. 1B in an enlarged manner, an annular groove 23 is formed on the outer diameter surface of the bracket 2, and a state in which the engaging portion 22 of the resin cover 21 is elastically deformed in the annular groove 23, so-called snap fit. Mounted by structure. As described above, in this embodiment, the drive components are all attached to the disc-shaped bracket 2 and the cup-shaped resin cover 21 is detachably attached to the bracket 2, and the drive components are attached to the resin cover 21. Therefore, it is possible to reliably prevent leakage of grease filled inside and intrusion of muddy water, oil, and the like from the outside. Furthermore, since the resin cover 21 can be attached to the bracket 2 with one touch, compared to the conventional case where the driving parts are attached to the housing divided into two parts, the number of parts is increased by fastening the housing and the cost is increased due to an increase in assembly man-hours. Alternatively, it is possible to provide an electric linear actuator that can suppress an increase in the mass of the housing, reduce the number of parts, reduce the weight by a simple structure, reduce the number of assembly steps, and reduce the cost.

  FIG. 3A is a longitudinal sectional view showing a second embodiment of the electric linear actuator according to the present invention, and FIG. 3B is an enlarged view of a main part showing a mounting portion of the resin cover of FIG. Note that this embodiment basically differs from the above-described one only in the configuration of the resin cover, and the same reference numerals are given to the same parts and parts having the same functions or the same functions as the above-described embodiments. Therefore, detailed description is omitted.

  As shown in FIG. 3A, the electric linear actuator 24 includes a bracket 25 made of an aluminum alloy, an electric motor 3 attached to the bracket 25, and an input attached to a motor shaft 3a of the electric motor 3. A speed reduction mechanism 6 comprising a gear 4 and an output gear 5 meshing with the input gear 4, and a ball screw mechanism 8 for converting the rotational motion of the electric motor into the linear motion in the axial direction of the drive shaft 7 via the speed reduction mechanism 6. And.

  The bracket 25 is formed in a disc shape, and includes a first mounting hole 2a for receiving the input gear 4 and a second mounting hole 25a for receiving the nut 12 constituting the ball screw mechanism 8. A support bearing 18 that rotatably supports the nut 12 with respect to the bracket 25 is mounted in the second mounting hole 25a.

  Here, all the drive parts such as the ball screw mechanism 8 and the electric motor 3 are assembled to the bracket 25, and the ball screw mechanism 8 among these drive parts is sealed by the resin cover 26. The resin cover 26 is formed by injection molding with a thermoplastic synthetic resin such as PA66 filled with a predetermined amount of a fibrous reinforcing material such as GF, and an annular locking portion 27 protruding to the outer diameter side at the opening end. It has.

  3B, an annular groove 28 is formed in the second mounting hole 25a of the bracket 25, and the engaging portion 27 of the resin cover 26 is elastically deformed in the annular groove 28. As shown in FIG. It is installed. As described above, in this embodiment, the drive parts are all attached to the disk-shaped bracket 25 and the ball screw mechanism 8 is sealed from the outside by the resin cover 26. It is possible to reliably prevent leakage to the outside and intrusion of muddy water or oil from the outside. Further, since the resin cover 26 can be attached to the bracket 25 with a single touch, the number of parts can be increased by fastening the housing as compared to the conventional case where the driving parts are attached to the housing divided into two parts, as in the above-described embodiment. An increase in cost due to an increase in assembly man-hours or an increase in the mass of the housing can be suppressed, the number of parts can be reduced, the weight of the simple structure can be reduced, and the number of man-hours for assembly can be reduced to reduce costs.

  The embodiment of the present invention has been described above, but the present invention is not limited to such an embodiment, and is merely an example, and various modifications can be made without departing from the scope of the present invention. Of course, the scope of the present invention is indicated by the description of the scope of claims, and further, the equivalent meanings described in the scope of claims and all modifications within the scope of the scope of the present invention are included. Including.

  An electric linear actuator according to the present invention is used in a drive unit of a general industrial electric motor, automobile, etc., and has a ball screw mechanism that converts rotational input from an electric motor into linear motion of a drive shaft via the ball screw mechanism. It can be applied to the provided electric linear actuator.

1, 24 Electric linear actuator 2, 25 Bracket 2a 1st mounting hole 2b, 25a 2nd mounting hole 3 Electric motor 3a Motor shaft 4 Input gear 5 Output gear 6 Reduction mechanism 7 Drive shaft 8 Ball screw mechanism 9 Counter mounting member DESCRIPTION OF SYMBOLS 10 Screw shaft 10a, 12a Screw groove 11 Oil seal 12 Nut 13 Key 14 Ball 15 Key groove 16, 19 Retaining ring 17 Flange 18 Support bearing 20 Piece member 21, 26 Resin cover 22, 27 Locking part 23, 28 Annular groove 50 Electric linear actuator 51 Ball screw 52 Actuator body 53 Electric motor 53a Motor shaft 54 Gear reduction mechanism 55 First gear 56 Position holding mechanism 57 Screw shaft 57a, 58a Screw groove 58 Nut 59 Ball 60 Housing 61, 62 Ball bearing 63 Second gear 64 Shaft 65 Solenoid 66 Receiving part

Claims (11)

A disk-shaped bracket;
An electric motor attached to the bracket;
A speed reduction mechanism for transmitting the rotational force of the electric motor via the motor shaft;
A ball screw mechanism that converts the rotational motion of the electric motor to linear motion in the axial direction of the drive shaft via the speed reduction mechanism;
This ball screw mechanism is rotatably supported via a support bearing mounted on the bracket and is not axially movable, and a nut having a helical thread groove formed on the inner periphery,
The nut is inserted through a large number of balls, is integrated coaxially with the drive shaft, and a helical thread groove corresponding to the thread groove of the nut is formed on the outer periphery, so that it cannot rotate with respect to the bracket. And an electric linear actuator composed of a screw shaft supported so as to be axially movable,
The speed reduction mechanism and the ball screw mechanism are assembled to the bracket, a cup-shaped cover is detachably attached to the bracket, and the ball screw mechanism is sealed from the outside by the cover. Electric linear actuator.   The electric linear actuator according to claim 1, wherein the electric motor is sealed from the outside by the cover.   The cover is formed by injection molding of a thermoplastic synthetic resin, and has an engaging portion protruding in the radial direction at an opening end portion, and an annular groove is formed in the bracket, and the cover is engaged in the annular groove. The electric linear actuator according to claim 1 or 2, wherein the portion is locked and the cover is mounted in an elastically deformed state.   The electric linear actuator according to claim 3, wherein at least three locking portions are formed in the circumferential direction.   The bracket includes a first attachment hole that accommodates an input gear that constitutes the speed reduction mechanism, and a second attachment hole that accommodates a nut that constitutes the ball screw mechanism, and the support is provided in the second attachment hole. The electric linear actuator according to claim 1, wherein a bearing is mounted.   2. The electric motor according to claim 1, wherein both end surfaces of the bracket are formed flat, one end surface is a mounting surface of a mating mounting part, and is joined in close contact, and the cover is mounted on the other end surface. Linear actuator.   The electric linear actuator according to claim 1, wherein the bracket is made of an aluminum alloy.   The electric linear actuator according to claim 1, wherein assembly directions of the electric motor and the ball screw mechanism are set in the same direction.   An output gear constituting the speed reduction mechanism is integrally fixed to the outer periphery of the nut via a key, and a flange is formed at one end of the nut, and the support bearing is sandwiched between the flange and the output gear. The electric linear actuator according to claim 1, wherein the electric linear actuator is externally fitted and fixed in a state.   The electric linear actuator according to claim 9, wherein the position of the flange of the nut is set in the same direction as the input gear and the sub-assembly of the electric motor.   The electric linear actuator according to claim 1, wherein the support bearing is a four-point contact ball bearing.

Images