JP2012215268A - Linear actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a linear actuator regulating movement of a screw shaft by a thrust and weakening impact force, even if an inner ring or an outer ring of one of radial bearings transmitted with a thrust load through the screw shaft is damaged.SOLUTION: This linear actuator includes: a housing 1 retaining the radial bearings 4, 5 in positions concentrically with each other and separated in a shaft length direction; the screw shaft 6 having one end part rotatably supported by the radial bearings 4, 5 in the housing 1; and an operating body 7 screwed around the screw shaft 6 to be relatively rotated. One end side from the radial bearings 4, 5, of the screw shaft 6 is interlockingly connected with a drive source, and the operating body 7 is reciprocated by rotation of the screw shaft 6. A movement restriction body 40 which is opposed to the end surface of the inner ring of each of the radial bearings 4, 5 and which restricts the movement of the screw shaft 6 by a thrust load applied to the screw shaft 6 is provided to the screw shaft 6 between the radial bearings 4, 5.

Description

  The present invention relates to a linear actuator that linearly moves forward / backward an operating body screwed to a screw shaft so as to be capable of relative rotation, and moves an appropriate object upward / downward.

  The linear actuator includes a screw shaft having one end portion rotatably supported by the two radial bearings in a housing that holds the two radial bearings at positions concentrically spaced in the axial length direction, and the screw An operating body screwed into the shaft so as to allow relative rotation; one end side of the screw shaft from the radial bearing is interlocked with an electric motor, and the operating body is moved upward by forward rotation of the screw shaft. And the actuating body is moved back downward by reverse rotation of the screw shaft (see, for example, Patent Documents 1 and 2).

  In the linear actuators of Patent Documents 1 and 2, the thrust load in one direction (downward) applied to the screw shaft through the operating body is transmitted to the inner ring of the radial bearing on the operating body side to prevent the screw shaft from moving downward. It is.

Japanese Utility Model Publication No. 4-62946 JP 2000-145914 A

  However, in the linear actuators described in Patent Documents 1 and 2, two radial bearings supporting one end of the screw shaft are separated in the axial length direction. In Patent Document 1, one direction applied to the screw shaft is described. (Downward) thrust load is configured to be transmitted to the inner ring of the radial bearing on the operating body side, and in Patent Document 2, the thrust load in one direction applied to the screw shaft is radial on the operating body side. Since the thrust load in the other direction applied to the screw shaft and transmitted to the inner ring in the bearing is transmitted to the inner ring in the radial bearing on the opposite side of the operating body, the screw is used when used frequently. It is considered that the inner ring or outer ring of the radial bearing may be damaged due to the eccentric load of the thrust load transmitted from the shaft to the radial bearing, the type of object attached to the operating body, changes in weight, etc., the eccentric load, etc. It is. If the inner ring or outer ring of the radial bearing is damaged, the thrust load applied to the screw shaft cannot be transmitted from the radial bearing to the housing, and the screw shaft moves relative to the housing due to the thrust load applied to the screw shaft. A strong impact force may be applied to the power transmission mechanism to the electric motor, the housing, and the like, and the housing and the like may be destroyed.

  SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and the main object is to provide a screw with a thrust load even if the inner ring or outer ring of one radial bearing to which the thrust load is transmitted via the screw shaft is broken. An object of the present invention is to provide a linear actuator that can restrict the movement of the shaft by a movement restricting body, reduce the amount of movement of the screw shaft, and reduce the impact force.

  Another object is to make the movement restricting body non-contact with the end face of each inner ring so that the radial bearing can be held in the housing without being affected by the movement restricting body. An object of the present invention is to provide a linear actuator capable of increasing the rotational stability of a shaft.

  Another object is to provide a movement restricting body on the screw shaft, and to provide a second movement restricting body on the housing opposite to the drive source side end surface of the outer ring in the second radial bearing on the drive source side. When the first radial bearing is damaged by the thrust load transmitted to the first radial bearing on the working body side, the thrust load is transferred from the movement restricting body to the housing through the second radial bearing and the second movement restricting body. The object is to provide a linear actuator capable of transmitting.

  Another object is to provide a movement restricting body on the screw shaft, and to provide a third movement restricting body facing the working body side end surface of the outer ring in the first radial bearing, so that the actuating body is located below the radial bearing. In the case where the second radial bearing is seriously damaged, the thrust load can be transmitted from the movement restricting body to the housing through the first radial bearing and the third movement restricting body. It is to provide an actuator.

  Another object is to provide a linear actuator capable of regulating the movement of the screw shaft when the radial bearing is broken without increasing the number of parts by providing a movement regulating body formed integrally with the housing. There is to do.

  The linear actuator according to the present invention is rotatably supported at one end thereof by each of the radial bearings in the housing in which the first and second radial bearings are accommodated and held at positions concentrically spaced in the axial length direction. A screw shaft and an operating body screwed into the screw shaft so as to be capable of relative rotation. One end side of each of the radial bearings of the screw shaft is coupled to a drive source, and the rotation of the screw shaft causes the rotation of the screw shaft. In the linear actuator capable of reciprocating the operating body, one of the peripheral surface of the screw shaft and the inner surface of the housing between the two radial bearings is opposed to the end surface of the inner ring of each of the radial bearings, and the screw shaft A movement restricting body that should restrict the movement of the screw shaft due to a thrust load applied to the screw shaft is provided.

  In the present invention, even if the inner ring or the outer ring of one of the radial bearings to which the thrust load is transmitted via the screw shaft may be damaged, the thrust load applied to the screw shaft is not affected by the amount of movement of the operating body. Since the inner ring of the damaged radial bearing can be immediately transmitted to the movement restricting body and transmitted from the movement restricting body to the housing, the movement of the screw shaft due to the thrust load can be restricted, and the amount of movement of the screw shaft can be reduced. While being able to reduce, the impact force added to a transmission mechanism, a housing, etc. can be weakened, and damage to a housing etc. can be prevented.

Further, the linear actuator according to the present invention is characterized in that the movement restricting body is not in contact with end faces of the inner rings.
In the present invention, since the radial bearing can be held in the housing without being affected by the movement restricting body, the rotational stability of the screw shaft by the radial bearing can be improved.

In the linear actuator according to the present invention, the movement restricting body is disposed on the screw shaft, and the housing is opposed to the drive source side end surface of the outer ring of the second radial bearing on the drive source side. And a second movement restricting body for restricting movement of the screw shaft due to the thrust load.
In the present invention, when the first radial bearing is damaged due to the thrust load when the object is pushed up, the thrust load applied to the screw shaft is applied to the first radial regardless of the upward movement amount of the operating body. Immediately transmitted from the inner ring of the bearing to the movement restricting body, immediately transmitted from the movement restricting body to the inner ring, rolling element and outer ring of the second radial bearing, transmitted from the outer ring to the housing via the second movement restricting body, and screw Since the downward movement of the shaft can be immediately controlled, damage to the power transmission mechanism and the housing can be prevented.

In the linear actuator according to the present invention, the screw shaft includes the movement restricting body and an abutting body that abuts on an end surface of the inner ring of the second radial bearing on the driving source side. The first radial bearing on the working body side has a third movement restricting body facing the working body side end surface of the outer ring and restricting the movement of the screw shaft by the thrust load.
According to the present invention, when the second radial bearing is seriously damaged by the thrust load during the suspension / lifting of the object, the thrust load applied to the screw shaft is immediately transmitted from the inner ring of the second radial bearing to the movement restricting body. The movement restricting body is immediately transmitted to the inner ring, the rolling element and the outer ring of the first radial bearing, and is transmitted from the outer ring to the housing through the third movement restricting body to immediately restrict the downward movement of the screw shaft. Therefore, damage to the power transmission mechanism and the housing can be prevented.

In the linear actuator according to the present invention, the screw shaft includes the movement restricting body and an abutting body that abuts on an end surface of the inner ring of the second radial bearing on the driving source side. A second movement restricting body that opposes the drive source side end face of the outer ring in the second radial bearing and restricts movement of the screw shaft due to the thrust load; and an operating body side of the outer ring in the first radial bearing. It has a 3rd movement control body which opposes an end surface and controls the movement by the said thrust load of the said screw shaft.
In the present invention, when one radial bearing is damaged due to a thrust load when the object is pushed up or when the object is suspended / lifted, the thrust load applied to the screw shaft immediately moves from the inner ring of the one radial bearing. Is transmitted to the restricting body, immediately transmitted from the movement restricting body to the inner ring, the rolling element and the outer ring of the other radial bearing, and transmitted from the outer ring to the housing via the second movement restricting body or the third movement restricting body. Since the movement of the power transmission mechanism can be immediately controlled, damage to the power transmission mechanism and the housing can be prevented.

In the linear actuator according to the present invention, the movement restricting body is formed integrally with the housing.
In the present invention, it is possible to restrict the movement of the screw shaft when the radial bearing is damaged without increasing the number of parts, and it is possible to prevent damage to the power transmission mechanism and the housing, and to reduce the assembly man-hours. Can be reduced and the cost can be reduced.

  According to the present invention, even if the inner ring or the outer ring of one radial bearing to which the thrust load is transmitted via the screw shaft may be damaged, the thrust load applied to the screw shaft regardless of the moving amount of the operating body, Since it can be immediately transmitted from the inner ring of the damaged radial bearing to the movement restricting body and transmitted from the movement restricting body to the housing, the movement of the screw shaft due to the thrust load can be restricted. Damage can be prevented.

  In addition, according to the present invention, since the radial bearing can be held in the housing without being affected by the movement restricting body, the rotational stability of the screw shaft by the radial bearing can be improved.

  Further, according to the present invention, when the first radial bearing is seriously damaged by the thrust load at the time of pushing up the object, the thrust load applied to the screw shaft regardless of the amount of upward movement of the operating body is restricted. Since the body and the second movement restricting body are transmitted to the housing and the downward movement of the screw shaft can be immediately regulated, the power transmission mechanism and the housing can be prevented from being damaged.

  Further, according to the present invention, when the second radial bearing is seriously damaged by the thrust load during the suspension / lifting of the object, the thrust load applied to the screw shaft is transferred from the movement restricting body and the third movement restricting body to the housing. Since the transmission and the downward movement of the screw shaft can be immediately controlled, damage to the power transmission mechanism and the housing can be prevented.

  Further, according to the present invention, it is possible to restrict the movement of the screw shaft when the radial bearing is damaged without increasing the number of parts, and it is possible to prevent damage to the power transmission mechanism and the housing, and to assemble the man-hours. The cost can be reduced.

It is a vertical front view which shows the structure of the linear actuator based on this invention. It is an expanded vertical sectional view which shows the structure of the principal part of the linear actuator based on this invention. It is explanatory drawing which shows the other usage pattern of the linear actuator which concerns on this invention. It is the vertical front view which abbreviate | omitted one part which shows the other structure of the linear actuator which concerns on this invention. It is an expanded vertical sectional view which shows the structure of the principal part of the linear actuator based on this invention. It is explanatory drawing which shows the other usage pattern of the linear actuator which concerns on this invention.

Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments thereof.
Embodiment 1
FIG. 1 is a longitudinal front view showing a configuration of a linear actuator according to the present invention, and FIG. 2 is an enlarged longitudinal sectional view showing a configuration of a main part.

  The linear actuator shown in the drawing is a cylindrical housing 1 that penetrates vertically, a case 3 that is attached to the lower end of the housing 1 and supports the electric motor 2, and is vertically spaced on a central axis in the housing 1. The first and second ball bearings 4 and 5 held in this manner, the screw shaft 6 whose lower end is fitted and supported on the ball bearings 4 and 5, and the screw shaft 6 can be rotated relative to each other. A cylindrical actuating body 7 that moves forward / backward in the axial direction with respect to the screw shaft 6, and an outer cylinder that surrounds the actuating body 7 and whose lower end is screwed to the upper inner side of the housing 1. 8 and a power transmission mechanism 9 that interlocks and connects the lower end of the screw shaft 6 to the output shaft 21 of the electric motor 2 in the case 3. The ball bearings 4 and 5 constitute radial bearings.

  The housing 1 has a small-diameter bearing hole 11 opened at the lower end, and a large-diameter screw hole 13 that is continuous with the bearing hole 11 via a stepped portion 12 and opened at the upper end.

  At both upper and lower ends of the bearing hole 11, slightly large-diameter fitting holes 11d and 11e are provided through the stepped parts 11b and 11c to the non-fitting hole part 11a at the upper and lower center part, and the fitting hole parts 11d, The outer rings 41 and 51 of the ball bearings 4 and 5 are fitted and held in 11e, respectively. An annular third movement restricting body 20 that faces the end face of the outer ring 41 of the upper first ball bearing 4 is screwed into the screw hole 13, and a non-screw that is in contact with the third movement restricting body 20. The third movement restricting body 20 and the elastic ring 30 are attached between the lower end of the outer cylinder 8 screwed into the screw hole 13 and the step portion 12. There is a slight gap between the third movement restricting body 20 and the outer ring 41.

  An annular second movement restricting body 10 is provided at the lower end of the housing 1 so as to face the end face of the outer ring 51 of the lower second ball bearing 5. There is a slight gap between the second movement restricting body 10 and the outer ring 51.

  The screw shaft 6 includes a medium-diameter non-screw portion 63 that is connected to an upper screw portion 61 to which the operating body 7 is screwed via a step portion 62, a small screw portion 64 that is connected to the non-screw portion 63, and the small screw portion. 64 has a small-diameter fitting portion 65 extending through a step portion at the lower end portion, the non-screw portion 63 is fitted and supported in the inner rings 42 and 52 of the ball bearings 4 and 5, and the step portion 62 is an outer ring of the ball bearing 4. The thrust load applied to the screw shaft 6 is in contact with the end face 41 and is transmitted from the ball bearing 4 to the housing 1 through the stepped portion 11b of the non-fitting hole portion 11d. 66 is screwed, the step 62 of the screw shaft 6 is pressed against the inner ring 42 of the ball bearing 4 by thrust generated by the screwing of the nut 66, and the nut 66 is pressed against the inner ring 52 of the ball bearing 5. The five outer rings 41 and 51 are fixed to the fitting holes 11d and 11e. The screw portion 61 is a ball screw or a trapezoidal screw, but may be another angle screw, and its shape is not particularly limited. The nut 66 constitutes a contact body.

  Between the ball bearings 4, 5 of the non-screw part 63, the ball bearings 4, 5 are opposed to the end faces of the inner rings 42, 52 of the ball bearings 4, 5, and the thrust bearings applied to the ball bearings 4, 5 through the screw shaft 6 A movement restricting body 40 is provided for restricting the movement of the screw shaft 6 when either one is damaged.

  The movement restricting body 40 has a cylindrical shape, and a male screw 40a is screwed into a screw hole penetrating from one place in the circumferential direction, and is fixed to the non-screw portion 63 by the male screw 40a. The length of the movement restricting body 40 is shorter than the length of the non-screw part 63, and there is a slight gap between the outer rings 41 and 51 of the ball bearings 4 and 5 and the movement restricting body 40.

  The actuating body 7 has a screw cylinder 71 screwed to the screw shaft 6 and a cylindrical rod 72 screwed to the outer periphery of the upper end portion of the screw cylinder 71. A rotation stop groove (not shown) in the axial length direction is provided on the outer peripheral surface of 72, and a fixture 50 having a bifurcated portion is attached to the upper end of the rod 72, and a pin is attached to the bifurcated portion of the fixture 50. It is possible to attach an appropriate object.

  The screw cylinder 71 is formed to have a larger diameter than the third movement restricting body 20 and the elastic ring 30, and the lower end faces the elastic ring 30. In addition, a retaining collar is provided at the lower end of the rod 72.

  An end stopper 81 for limiting the amount of upward movement of the operating body 7 is provided inside the upper end portion of the outer cylinder 8. A rotation for engaging the rotation stop groove on the inner peripheral surface of the outer cylinder 8 to prevent the rotation of the operating body 7 and for moving the operating body 7 forward / backward in the axial direction when the screw shaft 6 rotates. A stop projection (not shown) is provided.

  The case 3 has an opening that is spaced apart in the lateral direction and opened upward. The lower end of the housing 1 is attached to one opening, and the output shaft 21 side of the electric motor 2 is attached to the other opening. The output shaft 21 is arranged in parallel with the screw shaft 6.

  The power transmission mechanism 9 includes two gears 91 and 93 attached to the fitting portion 65 of the screw shaft 6 and the output shaft 21, and an intermediate gear 92 that meshes with the gears 91 and 93. A driving force is transmitted to the screw shaft 6, and the screw shaft 6 is rotated forward / reversely.

  FIG. 3 is an explanatory view showing another usage pattern of the linear actuator according to the present invention. As shown in FIG. 1, the linear actuator configured as described above has a configuration in which the case 3 is placed on the ground or the like and the operating body 7 is erected, in other words, the operating body 7 is formed by the ball bearings 4 and 5. And the case 3 is suspended as shown in FIG. 3 and the operating body 7 is suspended, in other words, the operating body 7 is more than the ball bearings 4 and 5. It may be used in the form arranged on the lower side.

  As shown in FIG. 1, when the electric motor 2 is driven with the working body 7 standing upright, the driving force of the electric motor 2 is transmitted from the power transmission mechanism 9 to the screw shaft 6, and the screw shaft 6 is Due to the rotation, the operating body 7 moves upward (forward movement), and an appropriate object attached to the upper end of the operating body 7 by the fixture 50 can be pushed up, and by reverse rotation of the screw shaft 6, The operating body 7 moves downward (returns), and the object can be lowered. The load at the time of raising and lowering the object passes from the inner ring 42, the spherical body 43, and the outer ring 41 of the upper first ball bearing 4 through the fixture 50, the operating body 7, and the screw shaft 6 to the housing through the step portion 11b of the fitting hole portion 11d. 1 is transmitted.

  As shown in FIG. 3, when the electric motor 2 is driven with the operating body 7 suspended, the driving force of the electric motor 2 is transmitted from the power transmission mechanism 9 to the screw shaft 6. Due to the rotation, the operating body 7 moves downward, and an appropriate object attached to the tip of the operating body 7 with the fixture 50 can be suspended, and the reverse rotation of the screw shaft 6 causes the operating body 7 to be suspended. Can move upward and lift the object. The load at the time of hanging / lifting the object is from the inner ring 52, the spherical body 53 and the outer ring 51 of the second ball bearing 5 through the fixture 50, the operating body 7, the screw shaft 6 and the nut 66, and the stepped portion of the fitting hole 11e. It is transmitted to the housing 1 through 11c.

  Since the object is frequently moved up and down by the movement of the operating body 7 in this manner, the thrust load is frequently transmitted from the screw shaft 6 to the first ball bearing 4 or the second ball bearing 5. When the object is pushed up and the first ball bearing 4 is often damaged by the thrust load, the thrust load applied to the screw shaft 6 is applied to the first ball bearing 4 regardless of the upward movement amount of the operating body 7. It is immediately transmitted from the inner ring 42 to the movement restricting body 40, and immediately transmitted from the movement restricting body 40 to the inner ring 52, the spherical body 53 and the outer ring 51 of the second ball bearing 5, and from the outer ring 51 through the second movement restricting body 10. It is transmitted to the housing 1 and the downward movement of the screw shaft 6 can be immediately controlled, and the impact force can be weakened. That is, when the first ball bearing 4 is damaged as described above in a state where the movement restricting body 40 is not present and the amount of movement of the operating body 7 is large, the second ball bearing 4 is removed from the inner ring 42 of the first ball bearing 4. After a relatively strong impact force is applied to the inner ring 52 of the ball bearing 5 and the second ball bearing 5 is pulled downward from the fitting hole portion 11e, the lower end of the screw shaft 6 collides with the bottom portion of the case 3 and the bottom portion In addition, the power transmission mechanism 9 is damaged, and the lower end of the operating body 7 collides with the elastic ring 30 with a relatively strong impact force, and the housing 1 is damaged. By providing 40, the movement of the screw shaft 6 can be restricted while the screw shaft 6 has moved slightly downward, and the impact force is weak. Therefore, the second ball bearing 5, the power transmission mechanism 9, and the housing 1. Damage to the case 3, etc. can be prevented.

  When the second ball bearing 5 is continually damaged by the thrust load during the suspension / lifting of the object, the thrust load applied to the screw shaft 6 is immediately transmitted from the inner ring 52 of the second ball bearing 5 to the movement restricting body 40. The movement restricting body 40 is immediately transmitted to the inner ring 42, the spherical body 43 and the outer ring 41 of the first ball bearing 4, and is transmitted from the outer ring 41 to the housing 1 via the second movement restricting body 10, and below the screw shaft 6. Can be immediately controlled and the impact force can be reduced. That is, when the second ball bearing 5 is damaged as described above in the absence of the movement restricting body 40, the inner ring 52 in contact with the nut 66 is moved by the separation distance between the ball bearings 4 and 5, and the first ball bearing 5 is moved. The ball bearing 4 collides with the inner ring 42 with a relatively strong impact force, which may damage the first ball bearing 4 and the second movement restricting body 10.

Embodiment 2
FIG. 4 is a longitudinal sectional front view showing a part of another configuration of the linear actuator, and FIG. 5 is an enlarged vertical sectional view showing the configuration of the main part. In this linear actuator, instead of providing the movement restricting body 40 on the screw shaft 6, an annular movement restricting body 60 is provided in the non-fitting hole portion 11 a of the housing 1, and the first ball bearing 4 or the first ball bearing 4 is connected to the screw shaft 6. When the spherical body of the first ball bearing 4 or the second ball bearing 5 is damaged by the thrust load transmitted to the second ball bearing 5 and the inner ring 42 or 52 remains, the movement restricting body restricts the movement of the screw shaft 6. It can be controlled immediately at 60.

  When the housing 1 is molded, the movement restricting body 60 is molded integrally with the non-fitting hole portion 11a, and faces the end faces of the inner rings 42 and 52 of the ball bearings 4 and 5, respectively. There is a slight gap between the movement restricting body 60 and the inner rings 42 and 52.

  FIG. 6 is an explanatory view showing another usage pattern of the linear actuator according to the present invention. In the second embodiment, similarly to the first embodiment, the working body 7 is used in a standing form (see FIG. 4) and the working body 7 is suspended (see FIG. 6).

  When the first ball bearing 4 is broken due to the thrust load when the working body 7 is installed upright, the thrust load applied to the screw shaft 6 is increased regardless of the upward movement amount of the working body 7. It is immediately transmitted from the inner ring 42 of the single ball bearing 4 to the movement restricting body 60 integral with the housing 1, and the downward movement of the screw shaft 6 can be immediately restricted, and the impact force can be weakened.

When the second ball bearing 5 is seriously damaged by the thrust load in use in the form in which the operating body 7 is suspended, the thrust load applied to the screw shaft 6 is transferred from the inner ring 52 of the second ball bearing 5 to the housing 1. Immediately transmitted to the integral movement restricting body 60, the downward movement of the screw shaft 6 can be immediately regulated, and the impact force can be weakened.
Since other configurations and operations are the same as those of the first embodiment, the same components are denoted by the same reference numerals, and detailed descriptions and descriptions of the operations are omitted.

  In the embodiment described above, the cylindrical movement restricting body 40 or the annular movement restricting body 60 is provided. However, the movement restricting bodies 40 and 60 have a cross section in a direction perpendicular to the axis of the screw shaft 6. It may be a substantially C-shape, a substantially internal tooth shape, or a substantially abbreviated shape, and its form is not particularly limited.

  In the embodiment described above, the ball bearing is used as the radial bearing. However, a rolling bearing may be used.

  In the embodiment described above, the electric motor is used as the drive source for rotating the screw shaft 6. However, the drive source and the power transmission mechanism for rotating the screw shaft 6 are not particularly limited.

  Further, the linear actuator according to the present invention can be used not only for lifting / lowering / hanging / lifting an object, but also for horizontally pulling an object.

1 Housing 2 Electric motor (drive source)
4 First ball bearing (radial bearing)
41 outer ring 42 inner ring 5 second ball bearing (radial bearing)
51 Outer ring 52 Inner ring 6 Screw shaft 66 Nut (contact body)
7 Actuator 10 Second Movement Restrictor 20 Third Movement Restrictor 40, 60 Movement Restrictor

Claims (6)

  A screw shaft whose one end side is rotatably supported by each of the radial bearings in the housing in which the first and second radial bearings are accommodated and held at positions concentrically spaced in the axial length direction, and the screw shaft An operating body screwed so as to be capable of relative rotation is provided, and one end side of each of the radial bearings of the screw shaft is linked to a driving source, and the operating body can be reciprocated by rotation of the screw shaft. In the linear actuator, one of the peripheral surface of the screw shaft and the inner surface of the housing between the two radial bearings is opposed to the end surface of the inner ring of each of the radial bearings, and the screw shaft is caused by a thrust load applied to the screw shaft. A linear actuator having a movement restricting body that should be restricted from moving.   The linear actuator according to claim 1, wherein the movement restricting body is not in contact with an end face of each inner ring. The movement restricting body is disposed on the screw shaft,
The said housing has a 2nd movement control body which opposes the said drive source side end surface of the outer ring | wheel in the 2nd radial bearing by the said drive source side, and controls the movement by the said thrust load of the said screw shaft. The linear actuator described. The screw shaft includes the movement restricting body and an abutting body that abuts the end surface on the driving source side of the inner ring in the second radial bearing,
The said housing has a 3rd movement control body which opposes the said operation body side end surface of the outer ring in the 1st radial bearing by the said operation body side, and controls the movement by the said thrust load of the said screw shaft. Linear actuator. The screw shaft includes the movement restricting body and an abutting body that abuts the end surface on the driving source side of the inner ring in the second radial bearing,
The housing is opposed to the drive source side end surface of the outer ring of the second radial bearing, and restricts movement of the screw shaft due to the thrust load, and an outer ring of the first radial bearing. 3. The linear actuator according to claim 1, further comprising a third movement restricting body that opposes the actuating body side end face and restricts movement of the screw shaft due to the thrust load.   The linear actuator according to claim 1, wherein the movement restricting body is formed integrally with the housing.

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