JP2009038946A - Electric actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric actuator that has a simple structure reducing the component count and ensures easy adjustment to a desirable opening by a manual operation, while allowing a seating force to be continuously applied at a fully closed position. <P>SOLUTION: The electric actuator includes a torque limiting means that restrains transmission of a torque exceeding a given load to an output screw axis 4 via a drive transmission mechanism to transmit a torque of an electric motor 3 to the output screw axis 4, or a speed reduction gear mechanism to transmit a torque of an indicator lever 27 to the output screw axis 4. The torque limiting means comprises contacting parts 14a, 14b of a carrier 14, a torque resistor part 28, and a micro-switch 31. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electric actuator that transmits the rotation of an electric motor to an object to be driven.

  Some linear valves have a valve plug that opens and closes the valve opening in response to the axial movement of the output shaft (hereinafter referred to as the output screw shaft) of a threaded actuator. is there. In such a linear valve, when the valve is fully closed, it is necessary to keep pressing the valve plug against the valve opening with a constant load after the valve plug is moved to the fully closed position to prevent internal leakage. Yes (sheeting force applied).

  For example, Patent Document 1 discloses a conventional technique for applying a sheeting force by driving a motor at a fully closed position with a torque higher than that at the time of normal driving. In the flow control valve of Patent Document 1, a seating force is applied at a fully closed position by determining a valve closing position region and inputting a signal to the stepping motor at regular intervals after the valve is closed.

  Patent Document 2 discloses a valve actuator provided with a torque detection mechanism that uses a torque limiter that detects overtorque when the motor is driven and when the motor is manually operated. In the actuator of Patent Document 2, a torque limiter mechanism is interposed between a gear that constitutes a power transmission mechanism that transmits power to an output shaft and a power transmission shaft that is installed and installed on the output shaft. A load prevention function is provided.

JP-A-8-247323 JP 2004-19938 A

  The flow rate control valve disclosed in Patent Document 1 is effective for a valve type in which the full-closed position has a relatively small secular change, such as a ball valve, because the seating force is applied by judging the full-closed position each time. However, when the valve opening is controlled by bringing a valve plug into contact with the valve opening as in a linear valve, the seat ring may be worn by contact with the valve plug or fluid pressure.

  For this reason, in the structure which detects a fully closed position like patent document 1, when the fully closed position changed aging remarkably by wear of a seat ring, there existed a subject that the position made to drive with high torque will shift. In this case, the fully closed position must be reset with respect to the position discriminating means, and the adjustment work is troublesome.

  On the other hand, in the conventional actuator disclosed in Patent Document 2, it is necessary to separately provide a torque detection mechanism for driving the motor and a torque detection mechanism for manual operation, which increases the number of parts.

  In Patent Documents 1 and 2, manual adjustment of the valve opening generally performed in construction, adjustment, work at the time of power failure, etc. is not considered, and an appropriate seating force is applied at the fully closed position by manual operation. The structure to do is not disclosed.

  In manual operation, when adjusting by manually rotating the gear in the front stage of the deceleration mechanism in the actuator (on the electric motor side of the torque detection mechanism that provides the seating force), for example, to adjust from the fully open position to the fully closed position It is necessary to rotate dozens of times and the operability is deteriorated.

  On the other hand, when the final stage gear of the speed reduction mechanism is manually rotated to adjust the valve opening, the number of rotations is small, and the operation is small. Further, if a clutch mechanism for cutting off the connection between the electric motor as a drive source and the speed reduction mechanism is provided, manual operation can be easily performed without using a tool.

  However, in the configuration in which the final stage gear of the speed reduction mechanism is manually rotated and adjusted, it is impossible to continue to apply a constant load that maintains the fully closed position at the fully closed position. In addition, there is a possibility that a gap is left due to backlash on the front side of the speed reduction mechanism, and an internal leak occurs.

  The present invention has been made to solve the above problems, has a simple structure with a reduced number of parts, can be easily adjusted to a desired opening degree by manual operation, and is seated in a fully closed position. An object is to obtain an electric actuator capable of continuing to apply force.

  An electric actuator according to the present invention transmits an output shaft connected to a driven object, a first reduction gear train that transmits the rotational force of the electric motor to the output shaft, and a rotational force of a manual operation lever to the output shaft. When the rotational force transmitted to the output shaft through the second reduction gear train and the first reduction gear train or the second reduction gear train exceeds a predetermined value, the transmission of the rotational force to the output shaft is restricted. Torque limiting means.

  In the electric actuator according to the present invention, the torque limiting means is interposed between the first reduction gear train and the second reduction gear train, and a turning portion that is turned by a rotational force transmitted to the output shaft, Torque resistance that restricts the rotation of the rotating part when the rotational force transmitted to the output shaft is below a predetermined value, and allows the rotational part to rotate when the rotational force transmitted to the output shaft exceeds a predetermined value Means, and energization blocking means for detecting the rotation of the rotating portion and blocking the energization of the electric motor.

  The electric actuator according to the present invention includes an electric / manual switching clutch that disconnects the connection between the first reduction gear train and the electric motor.

  In the electric actuator according to the present invention, the manual operation lever is rotated by the rotational force of the electric motor transmitted through the first reduction gear train and the second reduction gear train.

  According to the present invention, the rotation exceeds a predetermined value via the first reduction gear train that transmits the rotational force of the electric motor to the output shaft or the second reduction gear train that transmits the rotational force of the manual operation lever to the output shaft. Since the torque limiting means for restricting the transmission of force to the output shaft is provided, the common torque limiting means is provided for the electric operation and the manual operation, so that the number of parts required for applying the present invention can be reduced. There is an effect that can be done.

  According to this invention, since the electric / manual switching clutch for disconnecting the connection between the first reduction gear train and the electric motor is provided, the manual operation lever can be rotated by disconnecting the connection with the electric motor during manual operation. On the other hand, there is an effect that the manual operation can be easily performed without applying a load from the electric motor.

  For example, after the output shaft is manually operated to the fully closed position of the valve, the torque limiting means restricts the rotational force exceeding a predetermined value corresponding to the seating force from being applied to the output shaft. The state in which the seating force is applied can be maintained by returning the connection between the electric motor and the first reduction gear train in a state where a load corresponding to is applied.

  According to the present invention, the manual operation lever is rotated by the rotational force of the electric motor transmitted through the first reduction gear train and the second reduction gear train, so that the manual operation lever for manually driving the output shaft is provided. And the pointer indicating the operation amount (for example, the valve opening) of the driven object accompanying the drive of the output shaft can be shared, and the number of parts necessary for applying the present invention can be reduced.

Embodiment 1 FIG.
FIG. 1 is a diagram showing the configuration of the electric actuator according to Embodiment 1 of the present invention, and shows a cross section along the axial direction of the output screw shaft of the electric actuator in order to explain the internal configuration. 2 is a cross-sectional arrow view along the line AA in FIG. 1, and FIG. 3 is a cross-sectional arrow view along the line BB in FIG. The example in the figure shows a case where the electric actuator of the present invention is applied to drive a linear valve.

  The electric actuator 1 according to the first embodiment includes a support plate 2 housed in a casing, an electric motor 3 disposed on the support plate 2, and a valve shaft of a linear valve (not shown) at one end on the lower side of FIG. The output screw shaft 4 to be connected, a power transmission mechanism for transmitting the rotation of the electric motor 3 to the output screw shaft 4, and a planetary gear mechanism configured to share the shaft core with the power transmission mechanism.

  The transmission gear 5 attached to the rotating shaft 3a of the electric motor 3 meshes with the large-diameter transmission gear portion 6a. The transmission gear portion 6a is formed coaxially with the small-diameter transmission gear portion 6b, and the transmission gear portions 6a and 6b rotate integrally around the fixed shaft 7. In addition, the transmission gear portions 6a and 6b can be connected to the electric motor 3 side and the output screw by changing the positions of the transmission gear portions 6a and 6b along the axial direction of the fixed shaft 7 as shown by arrows in FIG. A clutch mechanism for disconnecting the connection with the shaft 4 side is provided.

  In this clutch mechanism, in the electric operation, the transmission gear portions 6a and 6b are urged in the axial direction by the spring 7a provided on the fixed shaft 7, and the meshing position between the transmission gear portion 6b and the transmission gear portion 8a is maintained. Further, in the manual operation, by operating the clutch lever 7b, the transmission gear portions 6a and 6b are moved toward the support plate 2 along the fixed shaft 7 against the urging force of the spring 7a, and the transmission gear portion 6b and the transmission gear are moved. The meshing with the portion 8a can be released.

  The transmission gear portion 6b meshes with the large-diameter transmission gear portion 8a. The transmission gear portion 8 a is integrally formed with a small-diameter transmission gear portion 8 b coaxially, and the transmission gear portions 8 a and 8 b are attached so as to be integrally rotatable about the output screw shaft 4.

  On the outer peripheral surface of the output screw shaft 4, a screw portion 4 a that is screwed with the inner screw 12 a of the output gear 12 is formed. Further, a valve shaft of a linear valve (not shown) is coaxially connected to the lower end of the output screw shaft 4 in FIG. 1, and the valve shaft in the linear valve according to the movement of the output screw shaft 4 in the axial direction. A valve plug provided at one end of the valve opens and closes the valve opening to adjust the valve opening.

  1 and 2, a planetary gear 9 is arranged around the transmission gear portion 8b (four planetary gears 9 in the illustrated example). These planetary gears 9 are rotatably mounted around a fixed shaft 10 provided on the carrier 11, and mesh with a transmission gear portion 8 b serving as a sun gear and an internal gear 13 formed on the carrier 14. Thereby, the planetary gear 9 revolves around the transmission gear portion 8b while rotating around the fixed shaft 10 by the rotational torque from the electric motor 3 transmitted through the transmission gear portion 8b.

  Further, an output gear 12 is formed on the carrier 11 as shown in FIG. The internal screw 12 a formed on the output gear 12 is screwed with the screw portion 4 a of the output screw shaft 4. As a result, when the output gear 12 is rotated by the rotational torque transmitted from the electric motor 3, the output screw shaft 4 moves in the axial direction as indicated by an arrow in FIG.

  The power transmission mechanism (first reduction gear train) described above includes the transmission gear 5, the transmission gear portions 6a and 6b, the transmission gear portions 8a and 8b, the planetary gear 9, and the carrier that are attached to the rotating shaft 3a of the electric motor 3. 11 is composed of an output gear 12 and an internal gear 13 formed on the motor 11. This power transmission mechanism is a reduction gear that transmits the rotation of the electric motor 3 to the output screw shaft 4 at a desired reduction ratio by configuring the transmission gear portions 6a, 6b and the transmission gear portions 8a, 8b with appropriate gear diameters. Acts as a mechanism.

  As shown in FIG. 2, the carrier 14 is provided with contact portions 14 a and 14 b so as to project outward from the outer edge portion in the radial direction. Further, a torque resistance portion 28 that suppresses the rotation of the carrier 14 around the output screw shaft 4 to a certain rotational torque is provided on the contact portion 14a side, and the carrier 14 is provided on the contact portion 14b side. When 14 rotates around the output screw shaft 4, a micro switch (energization interruption means) 31 is provided that is pressed to switch on (or off).

  The torque resistance portion 28 includes a case 28a having an opening, a spring 30 provided in the case 28a, one end urged by the spring 30, and the other end inserted through the opening of the case 28a. And a transmission member 29 protruding in the direction. As shown in FIG. 2, two torque resistance portions 28 are arranged opposite to each other so as to sandwich the contact portion 14 a along the rotation direction around the output screw shaft 4 of the carrier 14. The two transmission members 29 are close to the contact portion 14a so that they do not contact the contact portion 14a at the same time, and a constant urging force is applied from the spring 30 via the contacted transmission member 29. It is transmitted to the contact portion 14a. As a result, the rotation of the carrier 14 is restricted until a rotational torque exceeding the biasing force of the spring 30 is applied.

  As shown in FIG. 2, two microswitches 31 are also arranged to face each other so as to sandwich the contact portion 14 b along the rotation direction around the output screw shaft 4 of the carrier 14. When a rotational torque exceeding the urging force of the spring 30 is applied and the carrier 14 rotates around the output screw shaft 4 by a predetermined angle or more, the contact portion 14b presses the switch portion 32a and the electric motor 3 is de-energized. Thus, by cutting off the electric current to the electric motor 3, excessive rotational torque exceeding a predetermined value is prevented from being transmitted to the output screw shaft 4 side.

  The fixed shaft 15 is provided on the back surface of the surface of the carrier 14 on which the internal gear 13 is provided, and the planetary gear 16 is attached to be rotatable about the fixed shaft 15. The planetary gear 16 meshes with the external gear portion 12 b of the output gear 12 and an internal gear 17 formed on the plate 18, and rotates around the fixed shaft 15 by the rotation of the output gear 12. In the example of FIG. 3, three planetary gears 16 are arranged around the outer gear portion 12 b of the output gear 12.

  The external gear 19 is provided on the back surface of the surface of the plate 18 on which the internal gear 17 is provided. The fixed shaft 21 is provided on the carrier 22, and the planetary gear 20 is attached so as to be rotatable about the fixed shaft 21. The output gear 12 is rotatably held on the base 24 by a bearing including an outer ring 25a on the base 24 side, an inner ring 25b on the output gear 12 side, and a bearing ball 26 sandwiched between the outer ring 25a and the inner ring 25b.

  An internal gear 23 is provided on the base 24, and the planetary gear 20 meshes with both the internal gear 23 and the external gear 19 of the plate 18. As a result, when the rotational force from the electric motor 3 is transmitted, the planetary gear 20 revolves around the external gear 19 while rotating around the fixed shaft 21.

A pointer attaching shaft 22a is provided on the back surface of the surface of the carrier 22 on which the fixed shaft 21 is provided.
4 is a cross-sectional view taken along the line CC in FIG. As shown in FIG. 4, the base 24 is formed with an arc-shaped long hole portion 24a having the output screw shaft 4 as an axis, and the pointer mounting shaft 22a is inserted into the long hole portion 24a. In addition, a pointer lever 27 is attached to an end portion of the pointer mounting shaft 22a protruding to the back side of the base 24 through the long hole portion 24a. One end of the pointer lever 27 is attached to the pointer mounting shaft 22a, and has a shape extending on the radiation from the axis of the output screw shaft 4, as shown in FIG.

  On the back surface of the base 24, a scale (%) corresponding to the valve opening is written along the long hole portion 24a, and the valve opening can be visually recognized depending on which scale the pointer lever 27 is located on. . In the example of FIG. 4, the valve opening degree is 0% (fully closed state), and the rotation of the electric motor 3 is decelerated by the planetary gear reduction mechanism and transmitted to the pointer lever 27 so that the pointer lever 27 is fully opened. Rotate approximately 90 ° from full to closed.

  The planetary gear mechanism (second reduction gear train) described above includes the external gear portion 12 b of the output gear 12, the internal gear 17 provided on the plate 18, the external gear 19, and the planetary gear 16 that meshes with the external gear portion 12 b and the internal gear 17. The internal gear 23 provided on the base 24 and the planetary gear 20 provided on the carrier 22 and meshed with the external gear 19 and the internal gear 23, respectively. A guide lever 27 for valve opening is attached to the carrier 22 of the planetary gear mechanism, and by appropriately configuring the combination of the planetary gear and the number of teeth of the internal gear, the desired operation amount and the desired operation speed are achieved. The pointer lever 27 can be operated according to the amount of movement of the output screw shaft 4 in the axial direction.

Next, the operation will be described.
(1) Electric operation (operation in the opening and closing directions)
The rotational torque of the electric motor 3 in the electric operation is transmitted through a path indicated by a white arrow in FIG. First, the rotation of the electric motor 3 is transmitted from the transmission gear 5 attached to the rotation shaft 3a to the transmission gear portion 6a meshing with the transmission gear 5a. As a result, the transmission gear portions 6 a and 6 b rotate integrally around the fixed shaft 7.

  When the transmission gear portion 6b rotates, the transmission gear portion 8a meshing with the transmission gear portion 6b rotates about the output screw shaft 4 together with the transmission gear portion 8b. The rotation of the transmission gear portion 8 b is transmitted to the planetary gear 9 and is transmitted to the output gear 12 via the planetary gear 9. As a result, the output gear 12 rotates around the output screw shaft 4, and the planetary gear 9 revolves around the transmission gear portion 8b while rotating around the fixed shaft 10.

  When the output gear 12 rotates, the rotation of the output gear 12 is transmitted to the output screw shaft 4 in which the internal screw 12a of the output gear 12 and the screw portion 4a are screwed together, and the output screw shaft 4 moves in the axial direction by screw movement. At the same time, the rotation of the output gear 12 is transmitted to the planetary gear 16 via the external gear portion 12 b and is transmitted to the internal gear 17 via the planetary gear 16.

  Here, the carrier 14 holding the planetary gear 16 does not rotate around the output screw shaft 4 when the transmitted rotational torque is smaller than the biasing force of the spring 30, and the planetary gear 16 rotates around the fixed shaft 15. Just do it. With the rotation of the planetary gear 16, rotational torque is transmitted to the internal gear 17, and the plate 18 provided with the internal gear 17 rotates around the output screw shaft 4.

  When the plate 18 rotates around the output screw shaft 4, rotational torque is transmitted to the planetary gear 20 via the external gear 19. As a result, the planetary gear 20 revolves as the sun gear while rotating around the fixed shaft 21, and as a result, the carrier 22 rotates around the output screw shaft 4. At this time, the pointer lever 27 indicates the valve opening according to the amount of movement of the output screw shaft 4 in the axial direction as the carrier 22 rotates.

  As described above, in the example of FIG. 4, the pointer lever 27 rotates about 90 ° around the output screw shaft 4 until the valve is fully opened to fully closed. As described above, in the present invention, since the rotation angle of the pointer lever 27 is small, there is no case where the pointer is rotated too much to know which opening is indicated. In addition, it is possible to reduce the operating force during manual operation by lengthening the pointer lever 27 and increasing the turning radius. As a result, the pointer lever 27 can also be used as an easy-to-use manual operation lever with a small operation angle or operation force.

(2) Full-closed operation in electric operation When the output screw shaft 4 moves in the valve closing direction and the valve plug comes into contact with the valve opening in the linear valve and becomes fully closed, the output screw shaft 4 is restricted from moving in the axial direction, and the rotation of the output gear 12 is also restricted. When the rotational torque of the electric motor 3 is further applied to the transmission gear portions 8a and 8b from this state, the transmission gear portions 8a and 8b rotate around the output screw shaft 4 with a load proportional to the rotational torque, and the rotational torque is converted to the planetary gear. 9 is transmitted.

  Here, since the carrier 11 holding the planetary gear 9 is formed integrally with the output gear 12 and the rotation of the output gear 12 is restricted, the rotational torque applied to the planetary gear 9 causes the internal gear 13 to rotate. Via the carrier 14. As described above, the contact portions 14 a and 14 b are provided on the outer edge portion of the carrier 14, and when rotational torque is applied to the carrier 14, the contact portion 14 a is transmitted to the transmission member 29 of the torque resistance portion 28. .

  Thereafter, when the rotational torque from the electric motor 3 exceeds the urging force of the spring 30 corresponding to the seating force when fully closed, the contact portion 14a presses the transmission member 29 in a direction opposite to the urging force of the spring 30. However, the carrier 14 rotates around the output screw shaft 4. At this time, the contact portion 14b of the carrier 14 presses the switch portion 32a of the microswitch 31, and the power supply to the electric motor 3 is interrupted. As a result, in the fully closed state, the valve plug is pressed against the valve opening with an appropriate load (sheeting force) without internal leakage.

(3) Manual operation (operation in the opening and closing directions)
In the first embodiment, the pointer lever 27 is used as a rotation lever during manual operation. The rotational torque generated by manually rotating the pointer lever 27 is transmitted through a path indicated by a black arrow in FIG.

  First, the clutch lever 7b is operated to release the engagement between the transmission gear portion 6b and the transmission gear portion 8a, thereby disconnecting the connection between the electric motor 3 side and the output screw shaft 4 side. Thereafter, when the pointer lever 27 is manually rotated, the carrier 22 is rotated around the output screw shaft 4 along with this, and this rotation is transmitted to the external gear 19 via the planetary gear 20.

  When rotational torque due to manual operation of the pointer lever 27 is transmitted to the plate 18 via the external gear 19, the plate 18 rotates around the output screw shaft 4. When the plate 18 rotates around the output screw shaft 4, rotational torque is transmitted to the planetary gear 16 via an internal gear 17 provided on the plate 18.

  As described above, the carrier 14 holding the planetary gear 16 does not rotate around the output screw shaft 4 while the rotational torque is not more than a predetermined value. At this time, the planetary gear 16 rotates around the fixed shaft 15 by the rotational torque transmitted through the internal gear 17, and transmits this rotational torque to the external gear portion 12b.

  When the rotational torque is transmitted to the external gear portion 12b via the planetary gear 16, the output gear 12 rotates around the output screw shaft 4, and the planetary gear 9 revolves around the transmission gear portion 8b. As a result, the output screw shaft 4 moves in the axial direction, and the valve opening is manually operated.

(4) Operation when fully closed during manual operation When the manual operation causes the output screw shaft 4 to move in the valve closing direction, the valve plug contacts the valve opening in the linear valve and becomes fully closed. The movement of the output screw shaft 4 in the axial direction is restricted, and the rotation of the output gear 12 is also restricted. As a result, the load for manually rotating the pointer lever 27 increases, and it can be recognized that the operator is fully closed.

  When the pointer lever 27 is further rotated from this state, the carrier 22 rotates around the output screw shaft 4 with a load proportional to the rotational torque, and the rotational torque is transmitted to the external gear 19 via the planetary gear 20. When the rotational torque is transmitted to the external gear 19, the plate 18 rotates around the output screw shaft 4 along with this, and the rotational torque is transmitted to the planetary gear 16 through the internal gear 17.

  Here, since the rotation of the output gear 12 is restricted, when the rotational torque is transmitted to the planetary gear 16 in this state, the rotational torque is transmitted as the rotational torque to the carrier 14 via the revolution force of the planetary gear 16. Is done. As described above, the contact portions 14a and 14b are provided on the outer edge portion of the carrier 14, and when rotational torque is applied to the carrier 14, this rotational torque is transmitted to the torque resistance portion 28 via the contact portion 14a. It is transmitted to the member 29.

  In this way, when the rotational torque due to manual operation of the pointer lever 27 exceeds the urging force of the spring 30 corresponding to the seating force when fully closed, the contact member 14a causes the transmission member 29 to oppose the urging force of the spring 30. The carrier 14 rotates around the output screw shaft 4 while pressing in the direction. In this state, the clutch lever 7b is operated to return to the meshing state of the transmission gear portion 6b and the transmission gear portion 8a, so that the valve plug is pressed against the valve opening with an appropriate load without internal leakage. Is maintained.

  Even if the pointer lever 27 is manually rotated while being connected to the electric motor 3 side without providing the clutch mechanism described above, the valve plug can be pressed against the valve opening with an appropriate load without internal leakage. In this case, the rotating shaft 3a of the electric motor 3 must be rotated by manual operation of the pointer lever 27, and the load of manual operation is large.

  Further, even if an excessive rotational torque exceeding a predetermined seating force is applied, the torque resistance portion 28 is adjusted so that the transmission member 29 is not pressed beyond a predetermined position, and the pointer lever 27 is manually operated to You may comprise so that a predetermined seating force may be given in the position where the transmission member 29 was fully pressed by the contact part 14a. For example, as shown in FIG. 4, the long hole portion 24a provided in the base 24 is configured so that the pointer mounting shaft 22a does not move in the closing direction beyond a predetermined position from the fully closed position. Thereby, the carrier 14 does not rotate more than a predetermined angle.

  As described above, according to the first embodiment, the power transmission mechanism that transmits the rotational force of the electric motor 3 to the output screw shaft 4 or the planetary gear mechanism that transmits the rotational force of the pointer lever 27 to the output screw shaft 4 is provided. Torque regulation comprising the contact portions 14a and 14b of the carrier 14, the torque resistance portion 28, and the microswitch (energization interruption means) 31 for restricting the rotational force exceeding the predetermined load from being transmitted to the output screw shaft 4 Since the means is provided, the common torque limiting means is provided for the electric operation and the manual operation, so that the number of parts necessary for applying the present invention can be reduced.

  Moreover, according to this Embodiment 1, since the clutch mechanism which consists of the spring 7a and the clutch lever 7b which cut | disconnects connection with a power transmission mechanism and the electric motor 3 is provided, connection with the electric motor 3 is interrupted | blocked at the time of manual operation Thus, manual operation can be easily performed without applying a load from the electric motor 3 to the rotation of the pointer lever 27.

  For example, when a pressing force is further applied at a position where the valve plug has closed the valve opening by manual operation of the pointer lever 27, the torque limiting means is activated, and in this state, the connection with the electric motor 3 side is restored to restore the seating force. Can be maintained.

  Furthermore, according to the first embodiment, the shaft center is made common to the output gear 12 that moves the output screw shaft 4 separately from the reduction gear mechanism that transmits the rotational force of the electric motor 3 to the output screw shaft 4. A planetary gear mechanism that transmits the rotational force of the pointer lever 27 to the output screw shaft 4 is configured, and the planetary gear mechanism is decelerated so that the planetary gears mesh with each other, and is integrated with the final stage carrier 22 to which the rotational torque is transmitted. Therefore, the pointer lever 27 can be used as an opening guide that has a large operating amount or operating speed of the rotating system and is easily visible.

  In the electric actuator 1 according to the first embodiment, since the rotation angle of the pointer lever 27 is small, there is no case where the pointer is rotated so much that the opening degree is not shown. Further, the amount of operation of the pointer lever 27 can be reduced by providing a gear for transmitting rotational torque to the pointer lever 27 on the output side of the torque limiter mechanism. In addition, by increasing the length of the pointer lever 27 and increasing the radius of rotation thereof, it is possible to reduce the operating force during manual operation. As a result, the pointer lever 27 can also be used as an easy-to-use manual operation lever with a small operation angle or operation force. Therefore, the number of parts required for applying the present invention can be reduced.

  In the first embodiment, as shown in FIG. 3, the configuration in which the three planetary gears 16 are arranged with the external gear portion 12b as the sun gear is shown, but the present invention is not limited to this. For example, the planetary gear and the internal gear may be connected via an idle gear, or may be configured by a normal one-stage gear or two-stage gear.

  In the first embodiment, the example in which the present invention is applied to the linear valve in which the output screw shaft 4 is moved in the axial direction by the rotation of the output gear 12 and the valve opening degree is controlled is shown. It is not limited.

  For example, the output shaft and the output gear may be integrally formed, and the valve opening degree of the linear valve may be controlled using the output shaft as a screw shaft. Furthermore, although the output screw shaft does not move in the axial direction, an actuator that controls the valve opening degree by moving the output gear in the axial direction may be configured.

  FIG. 5 is a diagram showing another configuration of the electric actuator according to the first embodiment, and shows a cross section along the axial direction of the output screw shaft of the electric actuator in order to describe the internal configuration. In FIG. 5, the same components as those in FIG. In the example of FIG. 5, the planetary gear 20B is provided on the base 24 and rotates around the fixed shaft 21B. The base 22B provided with the internal gear 23B that meshes with the planetary gear 20B is provided to be rotatable around the output screw shaft 4. In addition, a pointer lever 27 is connected to the base 22B via a pointer mounting shaft 22b, and the pointer lever 27 rotates around the output screw shaft 4 as the internal gear 23 rotates.

  When the planetary gear 16 rotates around the outer gear portion 12b, the rotational torque is transmitted to the planetary gear 20B via the internal gears 17 and 19 provided on the plate 18. As a result, the planetary gear 20B rotates around the fixed shaft 21B provided on the base 24, and as a result, the base 22B rotates around the output screw shaft 4 via the internal gear 23B. At this time, the pointer lever 27 indicates the valve opening according to the amount of movement of the output screw shaft 4 in the axial direction with the rotation of the base 22B. By configuring in this way, the same effect as in the first embodiment can be obtained.

1 is a diagram illustrating a configuration of an electric actuator according to Embodiment 1. FIG. It is a cross-sectional arrow view along the AA line in FIG. It is a cross-sectional arrow view along the BB line in FIG. It is a cross-sectional arrow view along the CC line in FIG. It is a figure which shows the other structural example of the electric actuator by Embodiment 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric actuator 2 Support plate 3 Electric motor 3a Rotating shaft 4 Output screw shaft 4a Screw part 5 Transmission gear 6a, 6b, 8a, 8b, 16b Transmission gear part 7, 10, 15, 15a, 21, 21B Fixed shaft 7a Spring 7b Clutch lever 9, 16, 16a, 20, 20B Planetary gear 11, 14, 22 Carrier 22B Base 12 Output gear 12a Internal screw 12b External gear portion 13, 17, 23, 23B Internal gear 14a, 14b Contact portion 18 Plate 19 External gears 22a, 22b Pointer mounting shaft 24 Base 24a Long hole 25a Outer ring 25b Inner ring 26 Bearing ball 27 Pointer lever 28 Torque resistance part 28a Case 29 Transmission member 30 Spring 31 Micro switch (energization interruption means)
32a switch part 33 idle gear

Claims (4)

An output shaft coupled to the driven object;
A first reduction gear train that transmits the rotational force of the electric motor to the output shaft;
A second reduction gear train that transmits the rotational force of the manual operation lever to the output shaft;
An electric actuator comprising torque limiting means for restricting transmission of a rotational force exceeding a predetermined value to the output shaft via the first reduction gear train or the second reduction gear train. Torque limiting means
A rotating unit interposed between the first reduction gear train and the second reduction gear train and rotating by a rotational force transmitted to the output shaft;
When the rotational force transmitted to the output shaft is less than or equal to a predetermined value, the rotation of the rotating portion is restricted, and when the rotational force transmitted to the output shaft exceeds the predetermined value, the rotational portion is rotated. Torque resistance means to allow
The electric actuator according to claim 1, further comprising an energization interrupting unit configured to detect energization of the electric motor by detecting the rotation of the rotation unit.   The electric actuator according to claim 1, further comprising an electric / manual switching clutch for disconnecting the connection between the first reduction gear train and the electric motor.   2. The electric actuator according to claim 1, wherein the manual operation lever is rotated by the rotational force of the electric motor transmitted through the first reduction gear train and the second reduction gear train.

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