JP2020005454A - Electric actuator - Google Patents

Abstract

To provide an electric actuator which can inhibit vibration of an electric motor at a high level.SOLUTION: An electric actuator includes: a case; an electric motor 5 incorporated into the case; and a motion conversion mechanism 4 which converts rotary motion of the electric motor 5 into linear motion. In the electric actuator in which the electric motor 5 is fixed to the case (the gear case 10) at one axial end part side and a conductive member 70 is connected to a motor terminal at the other end part side on the opposite side, an elastic member 38 is provided between the conductive member 70 and a case (a motor case 60).SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electric actuator.

  2. Description of the Related Art In recent years, electrification has progressed in order to save power and reduce fuel consumption of vehicles and the like. For example, a system for operating an automatic transmission, a brake, a steering, and the like of an automobile by the power of an electric motor has been developed and put on the market. .

  As an actuator used for such a purpose, for example, Japanese Patent Application Laid-Open Publication No. H11-163,009 discloses a device provided with a ball screw mechanism that converts a rotational motion of an electric motor into a linear motion and outputs the linear motion. Further, in Patent Document 1, a plate-like stay is attached to one end side in the axial direction of the electric motor, and the electric motor is fastened to an actuator case with bolts via the stay, thereby maintaining the position of the electric motor against vibration. Configurations with improved power have been proposed.

JP 2018-74790 A

  However, in the configuration proposed in Patent Document 1, since the electric motor is in a cantilevered state in which the electric motor is not supported at all on the side opposite to the side where the stay is provided, external vibration (engine (Vibration from the vehicle or vibration generated while the vehicle travels) is transmitted to the electric motor, there is a possibility that vibration occurs on the side where the electric motor is not supported. Therefore, the configuration proposed in Patent Document 1 is not sufficient for application under severe vibration conditions, and needs improvement.

  Therefore, an object of the present invention is to provide an electric actuator capable of highly suppressing the vibration of an electric motor.

  In order to solve the above problems, the present invention includes a case, an electric motor built in the case, and a motion conversion mechanism that converts a rotational motion of the electric motor into a linear motion, and the electric motor has one end in an axial direction thereof. In an electric actuator in which a conductive member is connected to a motor terminal on the other end side while being fixed to a case on the side of the unit, an elastic member is provided between the conductive member and the case. .

  In this manner, by providing the elastic member between the conductive member and the case, the other end of the electric motor opposite to the one end fixed to the case is elastically supported by the elastic member. Become. Thereby, even if vibration from the outside is transmitted to the electric motor, the vibration at the other end of the electric motor is absorbed by the elastic member, so that the vibration is highly suppressed.

  In the case where a holder for holding the conductive member is provided, an elastic member may be held between the holder and the case. In this case, the other end of the electric motor is elastically supported via the holder, so that the elastic member highly restricts the deflection at the other end of the electric motor.

  Further, the elastic member may be held between the holder and the case in the axial direction of the electric motor. In this case, since the elastic member is sandwiched in the axial direction of the electric motor, an elastic repulsive force is generated in the elastic member in the axial direction. Therefore, the axial resilience of the electric motor can suppress the axial vibration of the electric motor (axial component of the vibration). However, the vibration suppressed by the elastic member is not limited to the vibration in the axial direction of the electric motor, and the vibration in any other direction can also be suppressed. That is, the vibration in an arbitrary direction intersecting with the axial direction of the electric motor can be suppressed by the frictional force of the elastic member generated between the holder portion and the case and the elastic force acting on the elastic member in various directions.

  Alternatively, the elastic member may be an O-ring, a cylindrical portion may be provided on the holder portion, and the O-ring may be mounted on the outer periphery of the cylindrical portion. With such a configuration, the elastic member can be easily mounted, and workability is improved.

  In addition, the case may include a first case divided body and a second case divided body that are configured to engage with each other and to be assembled. In this case, the elastic member is interposed and held between the second case split body assembled to the first case split body and the holder, and is held and held between the second case split body and the holder. It is preferable that the second case split body is biased in a direction in which the second case split body is engaged with the first case split body by an elastic repulsive force of the elastic member. With such a configuration, it is possible to eliminate rattling at an engagement portion between the case divided bodies and to reliably engage the case divided bodies.

  ADVANTAGE OF THE INVENTION According to this invention, since the run-out of an electric motor can be suppressed to a high degree, malfunctions, such as breakage of components resulting from the run-out of an electric motor, are less likely to occur, and reliability that can be applied even under severe vibration environments is reduced. A high electric actuator can be provided.

It is a sectional view of an electric actuator concerning one embodiment of the present invention. It is a perspective view of a stay and a bolt which support an electric motor. FIG. 4 is a cross-sectional view showing a portion where a stay is fixed to a gear case. It is sectional drawing which shows the non-fixed end part side of an electric motor, and its peripheral part. It is a perspective view of an electric motor, a bus bar, and a holder part. It is a perspective view showing the state where a holder part was fixed to an electric motor. FIG. 3 is a perspective view of a main body and a cap of a motor case. It is sectional drawing which shows the part of an engagement part and an engaged part.

  FIG. 1 is a sectional view of an electric actuator according to one embodiment of the present invention. First, the overall configuration and operation of the electric actuator according to the present embodiment will be described with reference to FIG.

  An electric actuator 1 shown in FIG. 1 includes a motor unit 2 having an electric motor 5, a driving force transmitting mechanism 3 for transmitting a rotational movement of the electric motor 5, and a movement converting mechanism for converting the rotational movement of the electric motor 5 into a linear movement. 4 is the main configuration.

  The motor unit 2 includes the electric motor 5, a pair of bus bars 70 as a conductive member for supplying electric power to the electric motor 5, and a motor case 60 that houses the electric motor 5, the bus bar 70, and the like. In the present embodiment, an inexpensive (with brush) DC motor is used as the electric motor 5, but another motor such as a brushless motor may be used. Note that the motor case 60 here is configured separately from a case (housing) of the electric motor 5 itself, and a case (a case of an electric actuator that houses the entire electric motor 5 having its own case). Actuator case).

  The motor case 60 includes a cylindrical main body 61 serving as a first case division body that accommodates most of the electric motor 5, and a second case division fixed to one end (the left end in FIG. 1) of the main body 61. And a lid-shaped cap portion 62 as a body. Each bus bar 70 is formed by bending a metal plate member into a predetermined shape, and is held by a resin holder 71, respectively. Each bus bar 70 is connected by welding to a motor terminal 5d (see FIG. 6) of the electric motor 5 in a state where the holder 71 is fixed to the end (the left end in FIG. 1) of the electric motor 5. ing. The cap portion 62 is provided with a cylindrical connector portion 62a that protrudes in the axial direction, and the inner peripheral side of the connector portion 62a has a distal end portion of each bus bar 70 (on the opposite side to the side connected to the motor terminal). End). By connecting the other end of a power line extending from a power source (not shown) to the tip of the bus bar 70, power can be supplied from the power source to the electric motor 5.

  The driving force transmission mechanism 3 includes a driving gear 8 on the driving side and a driven gear 9 on the driven side that meshes with the driving gear 8. The drive gear 8 and the driven gear 9 are housed in a gear case 10. The drive gear 8 is a small-diameter gear having a smaller number of teeth than the driven gear 9, and is attached to the rotating shaft 5 a of the electric motor 5 so as to rotate integrally therewith. On the other hand, the driven gear 9 is a large-diameter gear having more teeth than the drive gear 8, and is attached to a nut 17, which will be described later, constituting the motion conversion mechanism 4 so as to rotate integrally therewith. ing.

  The drive gear 8 is rotatably supported by two bearings 11 and 12 at both ends in the axial direction. One of the two bearings 11 and 12 (the left side in FIG. 1) is held by being fitted into a cylindrical bearing holding member 13 fixed to an end of the electric motor 5, and the other (see FIG. 1). The bearing 12 (on the right side in FIG. 1) is held by being fitted into the gear case 10. The driven gear 9 is rotatably supported together with the nut 17 by double-row bearings 14 provided on the outer peripheral surface of the nut 17. The double-row bearings 14 are housed in a cylindrical sleeve 15 provided in the gear case 10, and movement in the axial direction is restricted by a retaining ring 16 mounted on the inner peripheral surface of the sleeve 15. As the double-row bearing 14, it is preferable to use a double-row angular ball bearing capable of supporting an axial load in both directions in addition to a radial load so that the nut 17 can be stably and reliably supported.

  When the electric motor 5 starts driving and the rotating shaft 5a of the electric motor 5 rotates, the drive gear 8 rotates integrally with the rotating shaft 5a, and the driven gear 9 rotates in conjunction with this. At this time, since the rotational motion from the electric motor 5 is transmitted from the drive gear 8 having a small number of teeth to the driven gear 9 having a large number of teeth, the rotation is reduced and the rotational torque is increased. In this way, by increasing the rotational torque and outputting the torque by deceleration between the drive gear 8 and the driven gear 9, a sufficient output can be obtained even with a small electric motor. Note that, unlike the present embodiment, the drive gear 8 and the driven gear 9 may be constituted by gears having the same number of teeth, and the rotational motion from the electric motor 5 may be transmitted without deceleration.

  The motion conversion mechanism 4 is a ball screw mechanism having a nut 17 as a rotating member, a screw shaft 18 as a direct acting member, and a number of balls 19. Helical grooves are formed on the inner peripheral surface of the nut 17 and the outer peripheral surface of the screw shaft 18, respectively, and a ball 19 is rotatably accommodated between these spiral grooves. The nut 17 is provided with a circulation member (not shown), and the circulation member causes the ball 19 to circulate along the spiral groove.

  The screw shaft 18 is inserted through the inner periphery of the nut 17 and is arranged in parallel with the rotating shaft 5 a of the electric motor 5. At the front end (left end in FIG. 1) of the screw shaft 18, a connection hole 18a is provided. By inserting a fastener such as a bolt into the connection hole 18a, the screw shaft 18 and the operation target are illustrated. The corresponding part of the used equipment is not connected. When the rotational movement of the electric motor 5 is transmitted to the nut 17 via the drive gear 8 and the driven gear 9, the nut 17 rotates, and the screw shaft 18 moves in one of the axial directions (forward or backward). . Conversely, when the electric motor 5 rotates in the reverse direction, the rotational movement is transmitted to the nut 17 via the drive gear 8 and the driven gear 9, and the screw shaft 18 moves to the other axial direction. As described above, the forward / backward rotation of the electric motor 5 causes the screw shaft 18 to move forward or backward, so that the operation target connected to the front end of the screw shaft 18 is operated.

  The rear end of the screw shaft 18 (the end opposite to the end on the operation target side) is covered with a screw shaft case 20. The screw shaft case 20 is fixed to the gear case 10 on the side opposite to the side where the motor case 60 is fixed.

  At the rear end of the screw shaft 18, a rotation preventing pin 21 is provided as a rotation restricting member for restricting the rotation of the screw shaft 18. The detent pin 21 is attached to the screw shaft 18 in a direction orthogonal or intersecting with the axial direction. Guide rollers 22 are rotatably attached to both ends of the rotation preventing pins 21 projecting from the rear end of the screw shaft 18 in the radial direction. Each guide roller 22 is inserted into a pair of guide grooves 20 a provided in the screw shaft case 20 and extending in the axial direction. As the guide roller 22 moves in the axial direction along the guide groove 20a, the screw shaft 18 moves forward or backward in the axial direction without rotating in the circumferential direction.

  On the screw shaft 18, a boot 23 for preventing foreign matter from entering the electric actuator 1 and a boot cover 25 for protecting the boot 23 are provided on the front end side of the nut 17. . The boot 23 includes a small-diameter end portion 23a, a large-diameter end portion 23b, and a bellows portion 23c connecting and connecting them to expand and contract in the axial direction. The small-diameter end 23 a is fixed to the outer peripheral surface of the screw shaft 18, and the large-diameter end 23 b is fixed to the outer peripheral surface of a tubular boot mounting member 24 attached to the boot cover 25. The boot cover 25 is disposed so as to cover the outside of the boot 23, and is integrally formed with the main body 61 of the motor case 60.

  When the boot 23 expands and contracts with the reciprocating motion of the screw shaft 18, the pressure inside the boot 23 fluctuates. In particular, when the axial movement amount of the screw shaft 18 is large, the bellows portion 23c is excessively deformed by the internal pressure fluctuation. There is a possibility that the durability of the bellows portion 23c may be reduced. Therefore, in order to prevent the bellows portion 23c from being damaged due to a change in the internal pressure of the boot 23, a ventilation filter 26 is provided in the screw shaft case 20. The ventilation filter 26 communicates with the internal space of the boot 23 through the inside of the electric actuator 1, and when the boot 23 expands and contracts, air flows in or out through the ventilation filter 26, thereby suppressing deformation of the bellows portion 23 c. You.

  A magnet 27 serving as a sensor target for detecting the axial position of the screw shaft 18 is provided on the outer peripheral surface of the screw shaft 18. On the other hand, a stroke sensor (not shown) is provided on the outer periphery of the motor case 60. When the screw shaft 18 moves forward or backward, the stroke sensor detects a change in the magnetic field (for example, the direction and strength of the magnetic flux density) of the magnet 27 that moves with the screw shaft 18, and thereby the axial position of the magnet 27, and thus the screw shaft 18 axial positions are detected.

  Here, the support structure of the electric motor 5 in the electric actuator 1 according to the present embodiment will be described with reference to FIGS.

  As shown in FIG. 2, a plate-shaped stay 40 as a support member is fixed to two end faces of the electric motor 5 on the side where the rotating shaft 5 a protrudes. Specifically, a hole 40a is provided in the center of the stay 40, and two bolts 41 are provided on the stay 40 in a state where the rotary shaft 5a of the electric motor 5 is inserted through the hole 40a. The stay 40 is fixed to the end face of the electric motor 5 by screwing into the screw hole 5b provided on the end face of the electric motor 5 through the bolt insertion hole 40b. Further, the stay 40 is provided with bolt insertion holes 40c through which another two bolts 42 are inserted, and the bolts 42 are inserted into these bolt insertion holes 40c, and as shown in FIG. The stay 40 is fixed to the gear case 10 by screwing it into the screw hole 10 a provided in the gear case 10. Thereby, the electric motor 5 is fixed to the gear case 10 via the stay 40.

  As described above, in the electric actuator 1 according to the present embodiment, the electric motor 5 is fixed to the gear case 10 via the stay 40 at one axial end thereof. On the other hand, the other end of the electric motor 5 in the axial direction is not fastened to the motor case 60 by bolts or the like. If there is no support for the electric motor 5 at the other end side (hereinafter, referred to as “anti-fixed end side”), since the electric motor 5 is cantilevered, vibration from outside (for example, There is a problem in applying an electric actuator in a vibration environment exposed to vibration from an engine or vibration generated during running of a vehicle. Specifically, when vibrations from the outside are transmitted to the electric motor 5, the deflection of the electric motor 5 tends to increase particularly at a position apart from the fixed end of the electric motor 5 (opposite the fixed end). In the configuration in which the motor terminal 5d and the bus bar 70 are connected on the side opposite to the fixed end of the electric motor 5 as in the present embodiment, the welded portion between the motor terminal 5d and the bus bar 70 is damaged due to the vibration. For example, there is a possibility that these connection states cannot be maintained satisfactorily. For example, if the holder 71 fixed to the electric motor 5 collides with the inner surface of the motor case 60 before the electric motor 5 when the deflection occurs on the side opposite to the fixed end of the electric motor 5, the collision While the movement (shake) of the holder 71 is regulated by the force (the force in the direction opposite to the direction of the shake), the non-fixed end of the electric motor 5 is further moved toward the inner surface of the motor case 60 by the inertial movement due to the shake. Because of the movement, movements in opposite directions occur between the holder 71 and the electric motor 5. In such a case, the opposing movements of the holder 71 and the electric motor 5 apply a load in a direction in which the motor terminal 5d and the bus bar 70 are separated from each other at a welding location. When such a load is repeatedly applied to the welded portion, the welded portion is damaged due to fatigue or the like, and the electric actuator 1 breaks down (control becomes impossible).

  Therefore, in the present embodiment, the following measures are taken in order to highly suppress the vibration on the side opposite to the fixed end of the electric motor 5.

  FIG. 4 is a cross-sectional view of the electric motor on the side opposite to the fixed end and its peripheral portion.

  As shown in FIG. 4, in the electric actuator 1 according to the present embodiment, a rubber as an elastic member is provided between the bus bar 70 and the motor case 60 in order to suppress the deflection of the electric motor 5 on the side opposite to the fixed end. O-ring 38 is provided. The O-ring 38 is held between the holder 71 for holding the bus bar 70 and the cap 62 of the motor case 60 in the axial direction of the electric motor 5.

  Hereinafter, the respective configurations of the holder 71 and the cap 62 that hold the O-ring 38 therebetween will be described in detail.

  As shown in FIG. 5, the holder portion 71 has a cylindrical portion 71a and a flange portion 71b protruding outside the outer peripheral surface of the cylindrical portion 71a. The holder 71 is integrated with the bus bar 70 by insert molding. Rectangular recesses 71c are formed in the flange portion 71b at positions that are symmetrical with each other by 180 °, and are arranged so that one end 70a of each bus bar 70 is exposed in each recess 71c. On the other hand, the other end 70b of each bus bar 70 is disposed so as to protrude in the axial direction from the space partitioned into the two cylindrical portions 71a. The flange 71b is provided with a pair of convex fitting portions 71d at locations different in phase by 90 ° from the concave portions 71c. On the side opposite to the fixed end of the electric motor 5, there is provided a concave fitting portion 5c capable of fitting with the convex fitting portion 71d of the flange portion 71b. As shown in FIG. 6, when the convex fitting portion 71 d of the holder portion 71 is fitted in the concave fitting portion 5 c of the electric motor 5 in the axial direction, the holder portion 71 Fixed to the fixed end. Then, in this state, one end 70a of each bus bar 70 is welded to the motor terminal 5d, so that they are electrically connected.

  Further, as shown in FIG. 5, on the outer peripheral surface on the distal end side of the cylindrical portion 71a, an axial mounting surface 71e on which the O-ring 38 is mounted is disposed along the axial direction of the cylindrical portion 71a. , Is formed in a direction intersecting with the axial direction of the cylindrical portion 71a, and a stepped portion formed by an abutting surface 71f against which the O-ring 38 is abutted is formed. As shown in FIG. 4, the O-ring 38 is mounted on the outer periphery of the mounting surface 71e, and is positioned in the axial direction by being abutted against the abutting surface 71f.

  As shown in FIG. 7, the cap portion 62 is provided with a pair of claw-shaped engaging portions 62b at positions symmetrical with each other by 180 °. On the other hand, the main body 61 is provided with a pair of introduction portions 61a into which the engagement portions 62b are introduced.

  As shown in FIG. 8, an engaged portion 61b that can engage with the engaging portion 62b is provided in the introduction portion 61a. The engagement structure between the engagement portion 62b and the engaged portion 61b is a so-called snap-fit type engagement structure. When the engaging portion 62b is introduced into the introduction portion 61a along the axial direction of the electric motor 5, each of the engaging portions 62b bends in a direction away from each other to elastically deform, and when reaching the engaged portion 61b, When the engaging portion 62b elastically returns, the engaging portion 62b is engaged with or engageable with the engaged portion 61b. As shown in FIG. 7, an annular protruding wall portion 62c that is continuous in the circumferential direction is provided on the inner peripheral surface of the connector portion 62a of the cap portion 62.

  As shown in FIG. 8, the annular protruding wall portion 62c cooperates with the abutment surface 71f provided on the holder portion 71 to form the O-ring 38 in a state where the cap portion 62 is attached to the main body portion 61. It is the part that is held between the two. That is, while the O-ring 38 is mounted on the mounting surface 71 e of the holder 71, the holder 71 is fixed to the electric motor 5, and the electric motor 5 is housed in the main body 61, the cap is closed. When the portion 62 is attached to the main body 61, the O-ring 38 is pushed in the axial direction of the electric motor 5 by the projecting wall portion 62 c of the cap portion 62, and the O-ring 38 is pressed against the abutting surface 71 f of the holder portion 71. Can be As a result, the O-ring 38 is held between the projecting wall portion 62c and the abutting surface 71f while being compressed in the axial direction of the electric motor 5.

  As described above, in the electric actuator 1 according to the present embodiment, the O-ring 38 as an elastic member is provided between the abutting surface 71f of the holder 71 and the protruding wall 62c of the cap 62. Thus, the non-fixed end side of the electric motor 5 is elastically supported by the O-ring 38. That is, in the present embodiment, the non-fixed end of the electric motor 5, the holder 71 fixed to the non-fixed end, and the bus bar 70 held by the holder 71 are connected to the motor case 60. Although it is arranged with a gap with respect to the inner surface and is not fixed to the motor case 60, the electric motor 5 is not fixed because the holder 71 is in contact with the motor case 60 via the O-ring 38. The end side is elastically supported. Thereby, even if a run-out occurs on the side opposite to the fixed end of the electric motor 5, the run-out is absorbed by the O-ring 38, thereby suppressing the run-out and preventing the collision of the holder 71 with the inner surface of the motor case 60. Can be avoided. Alternatively, even if the holder 71 collides with the inner surface of the motor case 60, the impact due to the collision can be suppressed. As a result, the load at the welding point between the motor terminal 5d and the bus bar 70 due to the collision can be reduced, and damage to the welding point can be prevented.

  Here, in the present embodiment, since the O-ring 38 is compressed and held in the axial direction of the electric motor 5, the axial rebound of the electric motor 5 by the O-ring 38 causes the axial vibration (vibration) of the electric motor 5. Axial component) can be suppressed. However, the shake suppressed by the O-ring 38 is not limited to the shake in the axial direction of the electric motor 5, and the shake in any other direction can be suppressed. That is, due to the frictional force of the O-ring 38 generated between the holder 71 and the cap 62 and the elastic force acting in various directions of the O-ring 38, the vibration in an arbitrary direction intersecting with the axial direction of the electric motor 5 is also reduced. It is possible to suppress.

  As described above, according to the present invention, the run-out on the side opposite to the fixed end of the electric motor 5 can be highly suppressed, so that the connection state between the motor terminal 5d and the bus bar 70 can be maintained even under severe vibration environment. It is possible to provide a highly reliable electric actuator that can be maintained well.

  Further, since the O-ring 38 is sandwiched between the cap portion 62 and the holder portion 71 in the axial direction of the electric motor 5 as in the present embodiment, the engaging portion 62b of the cap portion 62 and the main body portion 61 are provided. Axial play with the engaged portion 61b can be eliminated. That is, since the O-ring 38 generates the above-described elastic repulsive force in the axial direction, the elastic repulsive force urges the engaging portion 62b in the direction of engagement with the engaged portion 61b. The joining portion 62b is securely engaged with the engaged portion 61b. Thereby, the assemblability of the cap part 62 to the main body part 61 is improved.

  As described above, the embodiments of the electric actuator according to the present invention have been described. However, the present invention is not limited to the above embodiments at all, and may be embodied in various forms without departing from the gist of the present invention. Of course.

  In the above-described embodiment, the O-ring 38 is adopted as the elastic member, and the O-ring 38 is mounted on the outer periphery of the cylindrical portion 71a, so that the elastic member can be easily mounted. The elastic member is not limited to the ring, and any other elastic member can be used as long as the vibration of the electric motor can be suppressed. Further, it is also possible to adopt a configuration in which the bus bar 70 is not held by the holder portion 71 (the holder portion 71 is not provided). In this case, the bus bar 70 is brought into direct contact with the elastic member to sandwich the elastic member between the case and the case. You may be able to do it.

  In the above-described embodiment, the case of the electric actuator 1 includes the motor case 60 including the main body 61 and the cap 62, the gear case 10, the screw shaft case 20, and the boot cover 25. The structure of the case is not limited to the above-described embodiment. The shape and division structure of the case can be appropriately changed according to the change of the specification of the internal structure of the electric actuator and the assembling property.

DESCRIPTION OF SYMBOLS 1 Electric actuator 3 Drive transmission mechanism 4 Motion conversion mechanism 5 Electric motor 38 O-ring (elastic member)
60 Motor case 61 Main body (first case divided body)
62 Cap part (second case divided body)
70 Bus bar (conductive member)
71 Holder 71a Cylindrical part

Claims (5)

A case, an electric motor built in the case, and a movement conversion mechanism for converting a rotational movement of the electric motor into a linear movement, wherein the electric motor is provided at one end in the axial direction with respect to the case. In the electric actuator, which is fixed and the conductive member is connected to the motor terminal on the other end side,
An electric actuator, wherein an elastic member is provided between the conductive member and the case. A holder for holding the conductive member,
The electric actuator according to claim 1, wherein the elastic member is held between the holder and the case.   The electric actuator according to claim 2, wherein the elastic member is held between the holder and the case in an axial direction of the electric motor. The elastic member is an O-ring,
A cylindrical portion is provided in the holder portion,
The electric actuator according to claim 2, wherein the O-ring is mounted on an outer periphery of the cylindrical portion. The case has a first case divided body and a second case divided body that are configured to be engaged with each other and assembled.
Holding the elastic member between the second case divided body assembled to the first case divided body and the holder,
Due to the elastic repulsive force of the elastic member held between the second case split and the holder, the second case split is engaged in a direction in which the second case split engages the first case split. The electric actuator according to any one of claims 2 to 4, wherein the electric actuator is configured to be energized.

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