JP2009115124A - Electric actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric actuator wherein a manual operating part is surely separated from an electric driving part in electrical operation so that damage of connection protruding part can be prevented. <P>SOLUTION: The electric actuator 1 includes the electric driving part 6 decelerating rotation of a motor 2 by reduction gear trains 3 and 4 and driving a valve, and the manual operating part 7 detachably connected to a driving shaft 3 of the reduction gear trains 3 and 4 and driving the valve. The manual operating part 7 is attached/detached to the driving shaft 3 by movement of a handle shaft housing 15 to an axial direction of the driving shaft 3, and the handle shaft housing 15 is locked by a lock shaft 26 in a detachment position. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electric actuator for driving various valves, and more particularly to an electric actuator having an electric drive unit and a manual operation unit.

  Many valves are used in power plants and the like, and electric actuators are mainly used to drive these valves. The electric actuator drives the stem of the valve by decelerating the rotation of the motor with a gear train.

  When opening and closing a valve using an electric actuator, normal operation is performed by energizing the motor. However, a manual operation unit is provided so that the valve can be opened and closed manually without using a motor during adjustment operation or in an emergency. Therefore, it is necessary to prevent manual operation during electric operation by the motor and to prevent electric operation by the motor during manual operation. Under such circumstances, an electric actuator including an electric drive unit and a manual operation unit has a built-in clutch as a fitting / removing mechanism.

  In an electric actuator according to the prior art, a worm shaft is linked to a motor through a reduction gear mechanism composed of a plurality of spur gears and the like, and is rotated forward and backward by the operation of the motor, and a pair of spur gears It is also linked to a handle shaft provided with a handle for manual operation via the shaft, and can be rotated forward and backward by rotating the handle with the clutch mechanism disengaged (for example, Patent Document 1). FIG. 3, paragraph 0004).

In addition, there is a manual gear shaft that meshes with a reduction gear train that is electrically driven, and a clutch mechanism is provided on the manual gear shaft to switch between electric operation and manual operation (see, for example, Patent Document 2).
Japanese Patent Laid-Open No. 7-310845 JP 2004-218735 A

  However, in the conventional electric actuator, the handle of the manual operation clutch has not been made inoperable even during electric operation. Even with such an electric actuator, the driven side of the clutch is rotating during electric operation, and even when operated in the direction of coupling the manual shaft connected to the manual handle, it is not connected to the driven side. Absent. However, when the manual handle is operated during an electric operation due to an erroneous operation or a falling object, the clutch coupling protrusion may be damaged.

  Although it cannot be said that manual operation is frequently required in an electric actuator, manual operation of a valve in a power plant or the like is necessary in an emergency. Therefore, high reliability and safety are required for operation. If an attempt is made to perform manual operation in an emergency, the coupling projection of the clutch should be damaged and the manual operation should not be hindered.

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an electric actuator in which the manual operation unit is reliably detached from the electric drive unit during electric operation and there is no possibility of damaging the coupling protrusion. And Another object of the present invention is to provide an electric actuator having a switching mechanism between electric operation and manual operation that is compact and economical.

  The invention according to claim 1 is an electric drive unit that drives a valve by reducing the rotation of a motor by a reduction gear train, and a manual operation unit that is detachably coupled to a drive shaft of the reduction gear train to drive the valve. The manual operation unit is engaged with and disengaged from the drive shaft when the handle shaft housing moves in the axial direction of the drive shaft, and the handle shaft housing is locked by the lock shaft in the disengaged position. It is characterized by that.

  According to a second aspect of the present invention, in the electric actuator according to the first aspect, a notch groove in a direction perpendicular to the axis is provided on the outer peripheral surface of the handle shaft housing, and the lock shaft is inserted into the notch groove. It is.

  According to a third aspect of the present invention, in the electric actuator according to the first or second aspect, the handle shaft housing is provided by providing a notch portion in the lock shaft and making the position of the notch portion coincide with the axial center position of the handle shaft housing. Is movable in the axial direction.

  According to a fourth aspect of the present invention, in the electric actuator according to any one of the first to third aspects, the manual operation portion is fitted to the drive shaft at a position pulled out with respect to a main body of the electric actuator, It is characterized by releasing at the pushed-in position.

  According to a fifth aspect of the present invention, in the electric actuator according to any one of the first to fourth aspects, a position sensor for detecting an axial position of the lock shaft is provided.

  A sixth aspect of the present invention is the electric actuator according to any one of the first to fifth aspects, wherein a speed reducer is incorporated in the manual operation section.

  According to the electric actuator according to any one of claims 1 to 3, the manual operation unit is engaged with and disengaged from the drive shaft when the handle shaft housing moves in the axial direction of the drive shaft. Securely restrained. Further, the lock shaft is inserted into a notch groove in a direction perpendicular to the axis provided on the outer peripheral surface of the handle shaft housing, and the position of the notch provided in the lock shaft is made to coincide with the axial center position of the handle shaft housing. The shaft housing can move in the axial direction. For this reason, the handle shaft housing cannot be moved unless the restriction by the lock shaft is released at the disengaged position, and the manual operation portion does not fit the drive shaft. Therefore, an electric actuator that requires high reliability and safety can be realized.

  According to the electric actuator of the fourth aspect, since the manual operation unit is fitted to the drive shaft at the position pulled out with respect to the main body of the electric actuator and is released at the pushed-in position, it is not during manual operation. The manual operation unit is in a position where it is pushed into the main body of the electric actuator. Therefore, the electric actuator such as the present invention in which the electric drive is in a normal state can have a compact external shape.

  According to the electric actuator of the fifth aspect, the axial direction position of the lock shaft can be detected by the position sensor and used as an interlock signal for the motor control circuit. Therefore, highly safe valve operation can be realized.

  According to the electric actuator of the sixth aspect, since the speed reducer is incorporated in the manual operation portion, the operation torque of the manual handle can be adjusted to an appropriate magnitude.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an embodiment of an electric actuator according to the present invention, and is a partial cross-sectional view of a plane orthogonal to a stem of a valve. The electric actuator 1 includes an electric drive unit 6 for driving the valve stem 5 by decelerating the rotation of the motor 2 by the worm shaft 3 and the worm wheel 4, and a valve stem that is detachably coupled to the worm shaft 3. 5 and a manual operation unit 7 for driving 5. The motor 2 is attached to one end of the main body 8 of the electric actuator, and the rotating shaft of the motor 2 is connected to the worm shaft 3 that is supported in the main body 8 of the electric actuator. A manual operation unit 7 is attached to the other end of the electric actuator.

  FIG. 2 is a cross-sectional view showing the manual operation unit 7 of the electric actuator according to the present invention. The manual operation unit 7 includes an adapter 11 fixed to the body 8 of the electric actuator, a handle shaft assembly 13 inserted in a hole 12 provided in the adapter 11 so as to be slidable in the axial direction, and the handle shaft assembly. And a lock shaft assembly 14 that restrains 13 axial movements.

  The handle shaft assembly 13 is slidable in the axial direction in a hole 12 provided in the adapter 11, but supports the handle shaft 16 in a handle shaft housing 15 inserted non-rotatably. A cylindrical key shaft-like groove 17 is provided on the outer peripheral surface of the cylindrical handle shaft housing 15, and the tip of the movement restricting pin 18 fixed to the adapter 11 is engaged with the groove 17. Are combined. As a result, the handle shaft housing 15 is slidable in the axial direction in the hole 12 provided in the adapter 11, but is inserted in a non-rotatable manner.

  Inside the cylindrical handle shaft housing 15, a handle shaft 16 is supported by bearings 19 and 19. A substantially cylindrical fitting / removing member 20 is fixed to the end 16a of the handle shaft 16 on the worm shaft side. An internal gear 22 having the same number of teeth as the external gear 21 provided at the shaft end of the worm shaft 3 is formed at one end of the fitting / removing member 20. That is, the external gear 21 and the internal gear 22 are configured to have a gear joint function. In addition, a space 23 is secured at the axially central portion of the fitting / removing member 20 so that the external gear 21 provided at the shaft end of the worm shaft can be stored with a margin. Further, the external gear 21 of the worm shaft is formed at the end of the worm shaft 3 via a neck portion 24 having an outer diameter smaller than the tip diameter of the internal gear 22 formed at one end of the fitting / removing member 20. ing. With such a configuration, when the handle shaft assembly 13 is moved in the axial direction, the external gear 21 and the internal gear 22 can be fitted and detached. The axial movement amount of the handle shaft assembly 13 is restricted by a groove 17 provided on the outer peripheral surface of the handle shaft housing 15 and a movement limiting pin 18 fixed to the adapter 11.

  A handle 25 for performing a manual operation is fixed to the other end of the handle shaft 16 pivotally supported in the handle shaft housing 15, that is, the opposite shaft end 16b to which the fitting / removing member 20 is fixed. The handle 25 is firmly fixed to the handle shaft 16, and the handle shaft assembly 13 is moved in the axial direction by pushing and pulling the handle 25 in the axial direction, and the external gear 21 and the internal gear 22 are fitted. Can be removed.

  3 and 4 are cross-sectional views taken along arrows AA in FIG. A lock shaft assembly 14 that restrains the axial movement of the handle shaft assembly 13 is attached to the adapter 11. The lock shaft assembly 14 is composed mainly of a lock shaft 26, a holder 27 that holds the axial position of the lock shaft, and a spring 28 that applies a biasing force between the lock shaft 26 and the holder 27. It is configured as.

  The lock shaft 26 has a small-diameter portion 26a that is slidably inserted into a hole 29 provided in the adapter 11, a large-diameter portion 26b that is accommodated in the holder 27, and the lock shaft 26 for manually operating the lock shaft 26. The holding portion 26c. A cutout 31 having a radius of curvature substantially the same as the outer peripheral surface of the handle shaft housing 15 is provided on the outer peripheral surface of the small diameter portion 26a. Further, a magnet 32 is attached to the tip of the small diameter portion 26a, and a compression coil spring 28 is attached to the root side connected to the large diameter portion 26b. Further, a notch groove 33 having a radius of curvature substantially the same as the outer diameter of the narrow diameter portion 26a of the lock shaft is provided on the outer peripheral surface of the handle shaft housing 15 in a direction perpendicular to the axis. The lock shaft 26 is provided at a position where the assembly 13 is pushed into the body side of the electric actuator.

  The large-diameter portion 26b of the lock shaft is accommodated in the hole 34 of the holder 27 having an inner diameter slightly larger than the outer diameter of the large-diameter portion. The outer peripheral portion is provided on the peripheral wall of the holder 27. A pin 36 that engages with the guide groove 35 is fixed. In addition, a grip portion 26c for operating the lock shaft 26 manually is provided at an end connected to the outside of the large diameter portion 26b.

  The holder 27 is fixed to the adapter 11, and a hole 37 having an inner diameter slightly larger than the outer diameter of the narrow diameter portion 26 a of the lock shaft is provided on the attachment surface side of the adapter at the center. In addition, a hole 34 having an inner diameter slightly larger than the outer diameter of the large-diameter portion 26b of the lock shaft is provided on the opposite side of the attachment surface to the adapter. Further, a spiral guide groove 35 is provided on the peripheral wall of the hole 34 in which the large-diameter portion 26b of the lock shaft is accommodated at 90 degrees in the circumferential direction, and both ends of the guide groove 35 are fixed to the lock shaft. An axial recess 38 (see FIG. 2) is provided so that the position of the pin 36 can be maintained.

  In the state shown in FIG. 3, the small diameter portion 26a of the lock shaft is inserted into the notch groove 33 provided on the outer peripheral surface of the handle shaft housing 15, and the axial movement of the handle shaft housing 15 is locked. That is, the axial movement is restrained in a state where the handle shaft assembly 13 is pushed into the main body 8 of the electric actuator, and the internal gear 22 of the fitting / disengaging member 20 fixed to the end of the handle shaft and the outer end of the worm shaft. The toothed gear 21 is detached. Therefore, even if the handle 25 is manually rotated in this state, the worm shaft 3 is not rotated by the rotation of the handle, and the electric operation can be performed safely.

  The state shown in FIG. 4 is a state in which the lock shaft 26 is rotated 90 degrees clockwise as viewed from the gripping portion 26c side from the state shown in FIG. When the lock shaft 26 is rotated 90 degrees clockwise from the state shown in FIG. 3, the entire lock shaft is moved outward (left side in the figure) by the pin 36 that engages with the spiral guide groove 35 provided in the holder 27. To do. As a result, the notch 31 provided in the narrow diameter portion 26a of the lock shaft faces the outer peripheral surface of the handle shaft housing 15, and the center position of the notch 31 coincides with the axial center position of the handle shaft housing 15. Is configured to do. In this state, the lock shaft 26 does not exist in the notch groove 33 of the handle shaft housing 15. Therefore, the axial movement of the handle shaft housing 15 is not constrained by the lock shaft 26, and the entire handle shaft assembly 13 is moved outward by applying a force in a direction in which the handle 25 is pulled out from the body 8 of the electric actuator. Is possible. When the entire handle shaft assembly 13 is moved outward from the main body 8 of the electric actuator, the internal gear 22 of the fitting / removing member 20 fixed to the handle shaft end and the external gear 21 of the worm shaft end are brought into mesh. The valve can be manually operated by rotating the handle 25.

  5 is a cross-sectional view taken along the line BB in FIG. The adapter 11 is provided with a position sensor 40 that detects the axial position of the lock shaft 26. As the position sensor, a commercially available general-purpose magnetic sensor 40 can be used. The strength of the lines of magnetic force from the permanent magnet 32 attached to the tip of the small diameter portion 26a of the lock shaft depends on the distance between the magnetic sensor 40 and the permanent magnet 32. Therefore, the position of the lock shaft 26 shown in FIG. 3 and the position of the lock shaft 26 shown in FIG. 4 or 5 can be easily detected and identified by the magnetic sensor 40. Although not shown, a signal line for sending a detection signal from the magnetic sensor 40 to the control circuit is provided. As a result, a signal from the magnetic sensor 40 is received by the control circuit, and the interlock function can be realized so that the power supply of the motor 2 of the electric actuator cannot be energized unless it is in the state of FIG.

  According to the embodiment described above, the handle shaft housing 15 is moved in the axial direction unless the restraint by the lock shaft 26 is released during the electric operation where the manual operation unit 7 is separated from the drive shaft 3. Therefore, there is no risk that the manual operation unit 7 moves in the direction of fitting with the drive shaft 3 during electric operation. That is, in order to switch from electric operation to manual operation, a redundant operation of always releasing the constraint by the lock shaft is necessary. Therefore, an electric actuator having high reliability and safety can be realized. Moreover, manufacturing cost can be reduced by setting it as a compact external appearance shape. Further, the position sensor 40 detects the axial position of the lock shaft 26 and can be used as an interlock signal for the control circuit of the motor 2. Therefore, highly safe valve operation can be realized.

  FIG. 6 shows a second embodiment of the electric actuator according to the present invention, and is a cross-sectional view of a manual operation unit. This embodiment is different from the above-described embodiment in that the speed reducer 41 is incorporated in the manual operation unit 7. The other configuration is the same as that of the above-described embodiment, and the description of the overlapping configuration is omitted. A speed reducer 41 that drives the handle shaft 16 by decelerating the rotation of the handle 25 is incorporated at the end of the handle shaft 16. The speed reducer 41 shown in the present embodiment is a planetary gear type speed reducer. When the handle 25 is rotated, the sun gear 43 formed at the tip of the input shaft 42 is rotated. The ring gear 44 is formed in the reduction gear housing 45. A plurality of planet gears 46 are engaged between the sun gear 43 and the ring gear 44, and a carrier 47 that supports the planet gear 46 is fixed to the handle shaft 16. Therefore, when the handle 25 is rotated, the rotation of the handle is decelerated and transmitted to the handle shaft 16. Since the speed reduction ratio is determined by the gear ratio of the speed reducer, the speed reduction ratio is selected to be a torque suitable for rotating the handle manually.

  According to the present embodiment, the operation torque of the manual handle can be adjusted to an optimum size for manual operation.

  As mentioned above, although this invention was demonstrated based on the Example, this invention is not limited to an above-described Example, Various deformation | transformation implementation can be performed. For example, a parallel shaft gear, a bevel gear, a planetary gear, or the like can be used for the reduction gear train of the electric actuator without using a worm gear. As for the speed reducer incorporated in the manual operation unit, another type of speed reducer can be used instead of the planetary gear type speed reducer.

It is a partial cross section figure which shows the Example of the electric actuator which concerns on this invention. It is sectional drawing which shows the manual operation part of the electric actuator which concerns on this invention. It is AA arrow sectional drawing in FIG. It is AA arrow sectional drawing in FIG. It is a BB arrow sectional view in Drawing 4. It is sectional drawing which shows 2nd Example of the electric actuator which concerns on this invention.

Explanation of symbols

1 Electric actuator 2 Motor 3 Reduction gear train (worm shaft, drive shaft)
4 Reduction gear train (worm wheel)
6 Electric drive unit 7 Manual operation unit 8 Body
15 Handle shaft housing
26 Lock shaft
31 Notch
33 Notch
40 Position sensor (magnetic sensor)
41 reducer

Claims (6)

An electric actuator comprising: an electric drive unit that drives a valve by reducing rotation of a motor by a reduction gear train; and a manual operation unit that is detachably coupled to a drive shaft of the reduction gear train to drive the valve. ,
The electric actuator according to claim 1, wherein the manual operation unit is engaged with and disengaged from the drive shaft when the handle shaft housing moves in the axial direction of the drive shaft, and the handle shaft housing is locked by the lock shaft at the disengaged position. 2. The electric actuator according to claim 1, wherein a notch groove in a direction perpendicular to the axis is provided on an outer peripheral surface of the handle shaft housing, and the lock shaft is inserted into the notch groove. 3. The handle shaft housing can be moved in an axial direction by providing a notch portion in the lock shaft and making the position of the notch portion coincide with the axial center position of the handle shaft housing. Electric actuator. The said manual operation part fits with the said drive shaft in the position pulled with respect to the main body of an electric actuator, and detach | leaves in the position pushed in. Electric actuator. The electric actuator according to claim 1, further comprising a position sensor that detects an axial position of the lock shaft. The electric actuator according to claim 1, wherein a speed reducer is incorporated in the manual operation unit.

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