JP7547745B2 - Electric actuator and flow control device - Google Patents

Description

The present invention relates to an electric actuator that opens and closes the valve body of a flow control device, and to a flow control device.

Prior art related to electric actuators and flow control devices is disclosed in the following Patent Document 1. Patent Document 1 discloses "an actuator for a shutoff valve having an operating shaft to which a rotational torque is applied in a direction to close the flow path of a shutoff valve, a DC motor that drives the operating shaft against the rotational torque, and a power transmission means that connects the operating shaft and the DC motor, the power transmission means being connected to the output shaft of the DC motor and including a clutch unit including a spur gear having a plurality of pawls in the circumferential direction and a pinion gear having a plurality of pawls that engage with the pawls, and a solenoid connected in parallel to the DC motor and driving the pinion gear to move forward and backward relative to the spur gear, a gear reduction mechanism that transmits the rotation of the pinion gear to the operating shaft, and a control circuit including a microswitch connected in series to the DC motor and the solenoid and a resistor connected in parallel to the microswitch, the microswitch being turned on when the shutoff valve is fully open, and a current that keeps the DC motor and the solenoid fully open is passed through the resistor." Patent Document 1 also describes a preferred shutoff valve actuator in which "the clutch portion has a compression coil spring that meshes the pawls of the spur gear with the pawls of the pinion gear." Patent Document 1 also describes that such a shutoff valve actuator "can reduce power consumption when the valve is held open without compromising the size and simplification of the actuator."

JP 2005-20967 A

The electric actuator of the above-mentioned Patent Document 1 is structured so that when electricity is not being applied, such as during a power outage, the force of the wound up torsion coil spring rotates the operating shaft in a direction that closes (or opens) the flow path, thereby closing (or opening) the shutoff valve. However, if the DC motor generates a holding torque (e.g., self-holding torque) that tries to maintain the state of the output shaft when electricity is not being applied, the clutch part is not disengaged due to the holding torque and the torque in the opposite direction caused by the torsion coil spring, and the valve body may not be able to be closed (or opened) quickly.

The present invention was made in consideration of the problems with the conventional technology described above, and aims to provide an electric actuator that opens and closes the valve body of a flow control device, and that can quickly open or close the valve body even when it is not energized, such as during a power outage.

[1] One aspect of the present invention that achieves the above object is to
An electric actuator for opening and closing a valve of a flow control device,
a main motor having a rotating shaft, which generates a holding torque when not energized;
an output shaft connected to the valve body;
a biasing means having a rotating shaft for biasing the valve body in a valve opening direction or a valve closing direction by inputting torque via the output shaft;
A transmission means having N (N≧2) gears for transmitting the torque of the main motor and the biasing means to the output shaft;
a control means for controlling the operation of the main motor; and a clutch configured to be connected by energization and to be disconnected by a force F1 when not energized is incorporated in the rotating shaft of the main motor, the output shaft, the rotating shaft of the biasing means, or the transmission means,
Furthermore, a force F2 that prevents the clutch from being disengaged is applied to the clutch, the force F2 being generated by the torque transmitted from the biasing means to the clutch,
The control means has a first control unit and a second control unit,
The first control unit outputs a signal to the main motor to rotate the main motor in a direction in which the valve body closes or opens, thereby rotating the main motor,
The second control unit is an electric actuator configured to operate the clutch so that F1>F2 is satisfied when the second control unit is not energized.

[2] In the electric actuator of [1] above, it is preferable that the clutch is incorporated in at least one of the gears that constitute the transmission means.

[3] Furthermore, in the electric actuator according to the above [1] or [2],
the clutch includes a first clutch portion connected to the main motor and having an engaging portion, and a second clutch portion connected to the biasing means and having an engaged portion that engages with the engaging portion,
It is preferable that the second control section is configured such that, when not energized, the first clutch section rotates in the same direction as the biasing direction of the biasing means.

[4] Furthermore, in the electric actuator according to [3] above,
The second control unit has a charging unit,
It is preferable that the charging unit is configured to use the charging unit as a power source and, when not energized, output a signal to the main motor to rotate the main motor in the direction in which the first clutch unit should rotate, thereby rotating the main motor.

[5] In addition, in the electric actuator according to the above [1] or [2],
the clutch includes a first clutch portion connected to the main motor and having an engaging portion, and a second clutch portion connected to the biasing means and having an engaged portion that engages with the engaging portion,
It is preferable that the second control section is configured such that, when de-energized, the second clutch section rotates in a direction opposite to a direction in which the biasing means biases the second clutch section.

[6] In addition, in the electric actuator according to [5] above,
a sub-motor that generates a torque in a direction opposite to the direction of the biasing means,
The second control unit has a charging unit,
It is preferable that the charging unit is configured to use the charging unit as a power source and to output a signal to the electric motor to rotate the auxiliary motor in a direction in which the second clutch unit should rotate when not energized, thereby rotating the auxiliary motor.

[7] Furthermore, in the electric actuator of the above [6] , it is preferable that the second control unit is configured to output, to the electric motor, a signal that causes the first clutch unit or the second clutch unit to rotate at a rotational acceleration of 23× ¹⁰ deg/sec2 or ^more .

[8] In addition, in the electric actuator according to any one of the above [3] to [7],
the first clutch portion is substantially cylindrical in shape and has the engaging portion at an end thereof,
the second clutch portion is substantially cylindrical and has the engaged portion at an end thereof,
The first clutch portion and the second clutch portion are coaxially arranged,
The engaging portion has a plurality of recesses and protrusions arranged at predetermined intervals around a central axis of the first clutch portion,
The engaged portion is formed with a plurality of recesses and protrusions around a central axis of the second clutch portion, the recesses and protrusions being formed to engage with the plurality of recesses and protrusions of the engaging portion,
a plurality of protruding portions of the engaging portion and the engaged portion each have a shape in which a tip thereof is tapered in a direction along a central axis of the first clutch portion, and both side surfaces of the protruding portions are inclined at the same angle around the central axis of the first clutch portion;
It is preferable that when the engaging portion and the engaged portion are engaged, a plurality of convex portions of the engaging portion and a plurality of convex portions of the engaged portion are all in contact around a central axis of the first clutch portion .

[9] In addition, in the electric actuator according to the above [1] or [2],
the clutch includes a first clutch portion connected to the main motor and having an engaging portion, and a second clutch portion connected to the biasing means and having an engaged portion that engages with the engaging portion,
Furthermore, the electric actuator has a separating means for moving the first clutch portion or the second clutch portion so that one of the engaging portion and the engaged portion is separated from the other,
It is preferable that the second control section is configured to operate the separating means when de-energized, to separate one of the engaging section and the engaged section, which are in an engaged state, from the other.

[10] Additionally, in the electric actuator according to [9] above,
The separating means includes a magnetic force generating unit that generates a magnetic force by energizing the magnetic field;
a drive unit that is connected to the first clutch unit or the second clutch unit and is driven by the magnetic force generating unit, the drive unit being disposed as necessary;
Furthermore, the second control unit has a charging unit,
It is preferable that the second control unit is configured, when not energized, to operate the magnetic force generating unit using the charging unit as a power source, and move the first clutch unit or the second clutch unit directly or indirectly via the drive unit, thereby separating one of the engaging unit and the engaged unit, which are in an engaged state, from the other.

[11] Additionally, in the electric actuator according to [9] above,
The separating means has a magnetic force generating unit that generates a magnetic force when energized,
the electric actuator has an extension member disposed between the engaging portion and the engaged portion and extending by a magnetic force;
Furthermore, the second control unit has a charging unit,
It is preferable that the second control unit is configured, when not energized, to operate the magnetic force generating unit using the charging unit as a power source and extend the extension member, thereby separating one of the engaging portion and the engaged portion, which are in an engaged state, from the other.

[12] Additionally, in the electric actuator according to [9] above,
The separating means has a heat generating portion that generates heat when energized,
the electric actuator has an expansion member that is disposed between the engaging portion and the engaged portion and expands when heated,
Furthermore, the second control unit has a charging unit,
It is preferable that the second control unit is configured, when not energized, to operate the heating unit using the charging unit as a power source and extend the extension member, thereby separating one of the engaging unit and the engaged unit, which are in an engaged state, from the other.

[13] In addition, in any of the electric actuators described in [2] to [12] above, when the torque generated by the biasing means is TA and the torque generated in each of the N gears constituting the transmission means by the torque being transmitted from the biasing means via the output shaft is TB (B=1 to N), it is preferable that the clutch is incorporated in a gear with TB/TA of 0.2 or less.

[14] Another aspect of the present invention is a flow control device that includes an electric actuator according to any one of [1] to [13].

According to the present invention, it is possible to provide an electric actuator that opens and closes the valve body of a flow control device, and that can quickly open or close the valve body even when electricity is not being applied, such as during a power outage.

1 is a schematic diagram of a flow rate control device according to an embodiment of the present invention having an electric actuator according to a first embodiment. 2 is a view taken along the arrow A of the internal structure of the electric actuator of FIG. 1 . 2 is another view taken along the arrow A of the internal structure of the electric actuator of FIG. 1 . FIG. This is a cross-sectional view taken along line B-B of FIG. FIG. 3 is a composite view showing cross sections taken along lines CC and DD in FIG. FIG. 4 is an enlarged view of part E in FIG. 4( a )的视图F图和G图。 FIG. 4 ( a ) arrow view and G arrow view. 2(a) is a cross-sectional view taken along the line HH in FIG. 2(a), and is a diagram for explaining the disengagement state of the clutch, and also serves as a diagram for explaining the disengagement state of the clutch of the prior art. FIG. 2 is a block diagram showing a circuit of the electric actuator of FIG. 1 . FIG. 11 is a partial enlarged view showing the internal configuration of an electric actuator according to a second embodiment of the present invention. 13A and 13B are diagrams for explaining a clutch disengagement state in the electric actuator of the second embodiment according to the present invention. FIG. 11 is a partial enlarged view showing the internal configuration of an electric actuator according to a third embodiment of the present invention. FIG. 10 is a partial enlarged view showing the internal configuration of an electric actuator according to a fourth embodiment of the present invention. FIG. 13 is a partial enlarged view showing the internal configuration of an electric actuator according to a fifth and sixth embodiment of the present invention.

The inventors of the present application have studied the application of the electric actuator of Patent Document 1, and have found the following problems, which led to the invention. That is, in the electric actuator of Patent Document 1, a torsion coil spring is attached to the operating shaft, and when the valve is opened, the torsion coil spring is wound up at the same time as the operating shaft is rotated by the DC motor, and the restoring force of the wound up torsion coil spring applies a rotational torque to the operating shaft in a direction to close the flow path of the shutoff valve. When the electric actuator of Patent Document 1 is to be put into a closed state, the DC motor and the solenoid actuator are simultaneously de-energized, and as shown in FIG. 5(a), the restoring force of the compression coil spring disengages the claw (corresponding to the convex portion in this application) 94n of the pinion gear (corresponding to the second clutch portion in this application) 94e from the claw (corresponding to the convex portion in this application) 94k of the spur gear (corresponding to the first clutch portion in this application) 94c, thereby disconnecting the clutch portion and disconnecting the DC motor from the power transmission mechanism. The rotational torque applied to the operating shaft as described above in a direction that closes the flow path of the shutoff valve rotates the operating shaft in the opposite direction to when the valve is open, and the shutoff valve (corresponding to the valve body in this application) is closed.

As shown in FIG. 5(a), which shows the state of the clutch immediately after a power outage, immediately after a power outage, the spur gear 94c constituting the clutch is fixed in position by the holding torque of the DC motor, and the pinion gear 94e is loaded with a pressing force W1 due to the restoring force of the torsion coil spring. Therefore, a force W2 equivalent to the pressing force W1 is loaded on the contact surface of the claws 94k, 94n where the spur gear 94c and the pinion gear 94e are engaged (meshed), and a predetermined friction force μFa1 is generated. Furthermore, with regard to the clutch, in addition to the friction force μFa1 at the contact surface between the clutch claws 94k, 94n as described above, friction forces are also generated at the contact surface between the gear in which the clutch is incorporated and another gear that meshes with the gear, and at the contact surface between the gear and the shaft on which the gear is mounted, due to the force loaded from the biasing means. The resultant force (force) F2 of these friction forces in the vertical direction acts downward to prevent the clutch from being disengaged. On the other hand, the clutch is configured to be disengaged by the force F1 acting upward due to the restoring force of a compression coil spring built into the clutch when the power supply from the external power source is stopped, but if F2>F1, the engagement between claws 94k and 94n may not be released and the clutch may not be disengaged. The inventors of the present application were aware of this phenomenon and came up with and completed the present invention to solve this problem.

The present invention will be described below based on the first to sixth embodiments with reference to Figs. 1 to 9. Fig. 1 is a schematic diagram of a flow control device having an electric actuator according to the first embodiment of the present invention, Fig. 2(a) is a view taken from the arrow A showing the internal structure of the electric actuator in Fig. 1, and Fig. 2(b) is another view taken from the arrow A showing the internal structure of the electric actuator in Fig. 1. Fig. 3(a) is a cross-sectional view taken from the line B-B in Fig. 2(a), and Fig. 3(b) is a composite view taken from the lines C-C and D-D in Fig. 2(b). Fig. 4 is an enlarged view of part E in Fig. 3(a), and Fig. 5 is a cross-sectional view taken from the line H-H in Fig. 2(a), which are diagrams for explaining the disengagement state of the clutch. Fig. 6 is a block diagram showing the circuit of the electric actuator in Fig. 1. FIG. 7 is a partially enlarged view showing the internal configuration of an electric actuator according to a second embodiment of the present invention, FIG. 8(a) is a partially enlarged view showing the internal configuration of an electric actuator according to a third embodiment of the present invention, FIG. 8(b) is a partially enlarged view showing the internal configuration of an electric actuator according to a fourth embodiment of the present invention, and FIG. 9 is a partially enlarged view showing the internal configuration of an electric actuator according to fifth and sixth embodiments of the present invention.

Here, Figures 2(a) and (b) are basically the same views as viewed from the arrow A, but in order to make it easier to understand the state of force (torque) transmission in the transmission means (gear reduction mechanism), etc., each force (torque) transmission path is shown as a separate diagram, and the main motor, solenoid actuator, etc. are shown with two-dot chain lines. Note that the present invention is not limited to the embodiments described below, and can be modified as appropriate without departing from the gist of the invention.

The electric actuator according to the first embodiment is an electric actuator 11 that opens and closes a valve body 12b in a flow control device 10, as shown in Fig. 1. The electric actuator 11 has a main motor 17 having a rotating shaft 17a that generates a self-holding torque (holding torque) when not energized, and an output shaft 11a connected to the above-mentioned valve body, as shown in Figs. 2 and 3. The electric actuator 11 also has a biasing means 15 having a rotating shaft 15a that biases the valve body in the valve opening direction or valve closing direction by inputting torque via the output shaft 11a, and a transmission means 13m consisting of nine (N) (N≧2) first gears (13a) to ninth gears (13i) that transmit the torque of the main motor 17 and the biasing means 15 to the output shaft 11a.

In the electric actuator according to the present invention, a clutch that is connected when energized and disconnected by force F1 when de-energized must be incorporated into either the rotating shaft of the main motor, the output shaft, the rotating shaft of the biasing means, or the transmission means. In the electric actuator 11 shown in FIG. 3, which is a specific embodiment, a clutch 14 is incorporated into the fifth gear (13e) shown in FIG. 4, among the first gear (13a) to the ninth gear (13i) that constitute the transmission means 13m. As shown in FIG. 2 and FIG. 3, a force F2 that prevents the clutch 14 from being disconnected, which is generated by the torque transmitted from the biasing means 15 to the clutch 14 via the output shaft 11a and the transmission means 13m, acts on this clutch 14 as shown in FIG. 4.

As shown in Fig. 6, the electric actuator according to this embodiment has a control means 11b for controlling the operation of the main motor 17, and the control means 11b has a first control section 11b3, a second control section 11b4, and a control circuit 11b2. Here, the first control section 11b3 is configured to connect the clutch described above and output a signal S1 to the main motor 17 to rotate the main motor 17 in a direction in which the valve body closes or opens, thereby rotating the main motor 17. The second control section 11b4 is configured to operate the clutch 14 when not energized so that the relationship between the forces F1 and F2 shown in Fig. 4 becomes F1>F2.

As explained above with reference to FIG. 5(a), conventionally, when the clutch is de-energized after the external power source is cut off, the relationship between the force F1 acting upward to disengage the clutch and the force F2 acting downward to prevent the clutch from being disengaged may be F2>F1, and the engagement between claws 94k and 94n may not be released, resulting in the clutch not being disengaged.

In contrast, according to the electric actuator of the present invention, the second control unit 11b4 shown in Fig. 6 is configured to operate the clutch so that F1>F2 when de-energized. More specifically, as described in detail below as an example of a preferred configuration (first embodiment), the second control unit 11b4 is configured to rotate the first clutch portion 14c shown in Fig. 5(b) in the same direction as the biasing direction of the biasing means (i.e., the acting direction of the pressing force W2 by the biasing means) when de-energized. Due to the rotation of the first clutch portion 14c, as shown in Fig. 5(b), the first clutch portion 14c moves with a rotational acceleration Ac, but the second clutch portion 14e momentarily holds its position due to inertia, and the two protrusions 14k, 14n are separated from each other. As a result, the force W2 acting on the contact surface between the convex parts 14k and 14n of the first clutch part 14c and the second clutch part 14e decreases, and the frictional force is reduced to μFa2 (when there is no contact, the frictional force is 0). A similar phenomenon occurs on the contact surface of the clutch other than the convex parts 14k and 14n, and the force F2 preventing the clutch from being disengaged is reduced, so that F1 (the force for disengaging the clutch)>F2 (the force for preventing the clutch from being disengaged), and the clutch is disengaged. The above-described disengagement mechanism reliably disengages the clutch immediately after a power outage, and as shown in Figures 2 and 3, the biasing means 15 inputs torque via the output shaft 11a in the valve opening direction or the valve closing direction to rotate the valve body, and opens or closes the valve to a predetermined opening degree. Hereinafter, the configurations of the electric actuators of the first to sixth embodiments according to the present invention and the flow control devices equipped with the electric actuators will be described in detail.

<Configuration of flow control device>
As shown in Fig. 1, the flow control device 10 according to the present embodiment includes a valve section 12 incorporating a valve body 12b, and an electric actuator 11 incorporating a main motor that controls and drives (opens and closes) the valve body 12b. The valve section 12 according to the present embodiment is a ball valve, and includes a valve box 12a having a substantially cylindrical flow passage 12d extending in the horizontal direction, a substantially spherical valve body 12b having a through hole portion 12f having a diameter substantially the same as that of the flow passage 12d and having a central axis arranged so as to be rotatable in a horizontal plane including the central axis I of the flow passage 12d, a seat ring 12c that slidably seals the valve body 12b, and a valve rod 12e that is connected to the center of the valve body 12b in an orientation perpendicular to the central axis I of the flow passage 12d. When the valve rod 12e rotates around its central axis, the valve body 12b rotates together with the valve rod 12e to open and close the flow passage 12d, thereby adjusting the opening degree of the ball valve 12. In this embodiment, a ball valve in which the valve body 12b driven by the electric actuator 11 is ball-shaped is used, but the valve is not limited to a ball valve, and for example, a well-known butterfly valve or an eccentric ball (plug) valve can also be used.

In the flow control device 10 in this embodiment, the valve body 12b is driven (opened and closed) by the output shaft 11a of the electric actuator 11 connected via the valve rod 12e. The output shaft 11a and the valve rod 12e of the ball valve 12 are fixed so that their central axes are coaxial, and the output shaft 11a is connected to the valve body 12b via the valve rod 12e. Therefore, when the output shaft 11a rotates a predetermined angle in a predetermined direction by driving the main motor, the valve body 12b also rotates the same angle in the same direction, changing the position of the through hole portion 12f of the valve body 12b in the flow path 12d, and the opening degree is adjusted. Note that the output shaft 11a and the valve rod 12e may be connected by a known fixing member (for example, an adapter, etc.) so that their central axes are coaxial as described above. As shown in FIG. 1, the output shaft 11a and the valve body 12b may be indirectly connected via the valve rod 12e, or the output shaft 11a and the valve body 12b may be directly connected without the valve rod 12e. The electric actuator 11 of the first embodiment incorporated in the flow control device 10 of the present embodiment will be described in detail below.

<Electric actuator: First embodiment>
As shown in Fig. 2 and Fig. 3, the electric actuator 11 of the first embodiment mainly comprises the output shaft 11a described above, a transmission means 13m connected to the output shaft 11a, a main motor 17 that rotates the output shaft 11a via the transmission means 13m, a potentiometer 18 that detects the rotation angle of the output shaft 11a, a control means 11b that controls the main motor 17, and a biasing means 15 that biases the valve body in a predetermined direction by inputting a force via the output shaft 11a. As shown in Fig. 3, the above-mentioned components are stored inside an upper case 11e and a lower case 11d that can be combined to form an enclosed space, and some of them are arranged on a first base plate (11c) fixed to the upper surface of the lower case 11d and a second base plate (11f) supported by a support. Each component will be described in detail below.

[Main motor]
The main motor 17 of this embodiment is a well-known synchronous motor having a rotating shaft 17a that rotates at a constant rotation speed at a constant frequency and generates a self-holding torque (holding torque) when not energized, and is advantageous in that it is highly efficient and small in size. As shown in Fig. 6, the main motor 17 is rotationally controlled by an opening/closing command signal S1 and an emergency opening/closing command signal S3 output from the control means 11b, and the rotating shaft can be rotated at a predetermined rotation speed in a predetermined direction (forward or reverse) for a predetermined period and then stopped. Note that the main motor 17 is not limited to a synchronous motor, and a direct current motor (DC motor) or an induction motor, which is a self-excited motor, may also be used.

[Transmission Means]
The transmission means 13m shown in Figures 2 and 3 is a reduction mechanism composed of a gear train of the first gear (13a) to the ninth gear (13i). Here, the transmission means 13m of this embodiment has two torque transmission paths, the first transmission means 13m1 and the second transmission means 13m2. That is, as shown in Figures 2(a) and 3(a), the first transmission means 13m1 is composed of a gear train of the first gear (13a) to the eighth gear (13h) interposed between the main motor 17 and the output shaft 11a, and transmits the torque generated by the main motor 17 to the output shaft 11a in the order of the first gear (13a), the second gear (13b), ..., and the eighth gear (13h). 2(b) and 3(b), the second transmission means 13m2 is composed of a gear train consisting of a seventh gear (13g), an eighth gear (13h), and a ninth gear (13i) interposed between the biasing means 15 and the output shaft 11a, and transmits the torque generated by the biasing means 15 to the output shaft 11a in the order of the ninth gear (13i), the seventh gear (13g), and the eighth gear (13h). Note that, in a plan view, the eighth gear (13h) whose center is fixed to the output shaft 11a is a gear shared by the first transmission means 13m1 and the second transmission means 13m2.

The tenth gear (13j), which is not included in the transmission means 13m, meshes with the eighth gear (13h) and rotates the potentiometer 18, which will be described later. The eleventh gear (13k) meshes with the sixth gear (13f) and transmits the braking torque of the brake 19, which will be described later, to the output shaft 11a. Specifically, in FIG. 2(b), the braking torque of the brake 19 is transmitted to the output shaft 11a in the order of the eleventh gear (13k), the sixth gear (13f), the seventh gear (13g), and the eighth gear (13h).

The first gear (13a) to the ninth gear (13i) constituting the transmission means 13m shown in Fig. 3 will be specifically described below. First, the first gear (13a) fixed to the rotating shaft 17a of the main motor 17, the eighth gear (13h) fixed to the output shaft 11a, and the ninth gear (13i) fixed to the rotating shaft 15a of the biasing means 15 are each a single spur gear having a predetermined number of teeth. The remaining second gear (13b) to seventh gear (13g) are gears in which two spur gears are formed in two stages, one above the other, in the central axis direction: a large-diameter spur gear with a large number of teeth (hereinafter sometimes referred to as a large-diameter gear) and a small-diameter spur gear with a small number of teeth (hereinafter sometimes referred to as a small-diameter gear). In the transmission means 13m, the second gear (13b) to the seventh gear (13g) are combined so that the large diameter gear meshes with the small diameter gear along the torque transmission direction of each of the first transmission means 13m1 and the second transmission means 13m2, and are configured to gradually reduce the speed. The second gear (13b) to the seventh gear (13g) are arranged to be rotatable around a support shaft whose both ends are fixed to the first base plate (11c) and the lower case 11d.

As described above, the transmission means 13m in this embodiment is a parallel-axis type reduction mechanism composed of multiple spur gear trains, but is not limited to this and may be, for example, an orthogonal type reduction mechanism such as a worm reducer, a concentric type reduction mechanism such as a planetary gear reducer, or a combination of these with a parallel-axis type reduction mechanism.

[clutch]
The clutch 14 incorporated in the fifth gear (13e) among the first gear (13a) to the ninth gear (13i) constituting the transmission means 13m will be described with reference to FIG. 4, which is an enlarged view of part E in FIG. 3(a). The fifth gear (13e) of this embodiment is made up of two elements, a first clutch portion 14c of a substantially cylindrical shape having teeth 14i which is a large-diameter spur gear meshing with the fourth gear (13d) and a second clutch portion 14e of a substantially cylindrical shape having teeth 14j which is a small-diameter spur gear meshing with the sixth gear (13f). The shaft 14o is inserted through the center holes of both the first clutch portion 14c and the second clutch portion 14e, and the first clutch portion 14c is disposed above and the second clutch portion 14e is disposed below so as to be coaxial with the center axis J. The large-diameter toothed portion 14i of the first clutch portion 14c is configured to be able to move up and down while sliding on the tooth surface of the fourth gear (13d) with which the large-diameter toothed portion 14i meshes.

Here, the clutch 14 is a meshing type clutch (so-called tooth type clutch), and an engaging portion 14d is formed at the lower end (end) of the first clutch portion 14c, and an engaged portion 14f is formed at the upper end (end) of the second clutch portion 14e. As shown in FIG. 4(b), which is a view seen from the arrow F in FIG. 4(a), a convex portion 14k and a concave portion 14l are formed in the engaging portion 14d. Also, as shown in FIG. 4(c), which is a view seen from the arrow G in FIG. 4(a), a concave portion 14m and a convex portion 14n are formed in the engaged portion 14f so as to engage with the convex portion 14k and the concave portion 14l of the engaging portion 14d. Note that the clutch of the electric actuator according to the present invention is not limited to the tooth type clutch applied in this embodiment, and various clutches such as a friction plate type clutch and an electromagnetic type clutch can be applied.

As shown in Fig. 4(a), a compression coil spring is incorporated between the first clutch portion 14c and the second clutch portion 14e as an elastic member 14g that expands when no load is applied, and is disposed between the end faces of the first clutch portion 14c and the second clutch portion 14e. Therefore, when no load is applied, the end faces of the first clutch portion 14c and the second clutch portion 14e are separated by a predetermined distance in the direction along the central axis J by the restoring force (force) F1 of the elastic member 14g. In addition, the solenoid shaft 14b of the solenoid actuator 14a (see Fig. 3) contacts the upper end face of the first clutch portion 14c via the bush pin 14h through which the shaft 14o is inserted. As a result, when electricity is applied, the solenoid actuator 14a operates and the solenoid shaft 14b expands downward, the first clutch portion 14c descends against the restoring force F1 of the elastic member (compression spring) 14g, and its engaging portion 14d engages with the engaged portion 14f of the second clutch portion 14e, and the clutch 14 is in an engaged state. On the other hand, if the power supply from the external power source is stopped due to a power outage or the like, and the solenoid shaft 14b is in a non-energized state and no load is applied, the first clutch portion 14c rises due to the restoring force F1 of the elastic member 14g, the engagement between the engaging portion 14d and the engaged portion 14f is released, and the clutch 14 is in a disconnected state.

In this embodiment, the clutch 14 is incorporated in the fifth gear (13e), but the gear in which the clutch 14 is incorporated may be another gear. However, in order to open the valve body, it is necessary to continue energizing the solenoid actuator during the valve opening period and to ensure that the clutch 14 is in a securely connected state, and it is desirable to be able to connect the clutch 14 with a small thrust. For this purpose, when the torque generated by the biasing means 15 shown in Figures 2 and 3 is TA and the torque generated in the eight gears constituting the transmission means 13m by transmitting the force from the biasing means 15 via the output shaft 11a is TB (B = 1 to 8), it is preferable that the clutch is incorporated in a gear with TB/TA of 0.2 or less. In this regard, in this embodiment, when the torque TA generated by the biasing means 15 is 0.745 (N.m), the torque T5 generated in the fifth gear (13e) in which the clutch 14 is incorporated is 0.0978 (N.m), and T5/TA = 0.13, so the above requirement is met.

As shown in Figure 4, the engaging portion 14d of the tooth-type clutch 14 has a plurality of recesses 14l and protrusions 14k arranged at a predetermined interval around the central axis B of the first clutch portion 14c, and the engaged portion 14f has a plurality of protrusions 14n and recesses 14m formed around the central axis B of the second clutch portion 14e so as to engage with the plurality of recesses 14l and protrusions 14k of the engaging portion 14d. In this case, in order to close or open the valve more quickly when no current is applied, as shown in Figure 5, it is desirable that the multiple protrusions 14k, 14n of each of the engaging portion 14d and the engaged portion 14f have a shape that narrows at the tip in the direction along the central axis of the first clutch portion 14c, and that both side surfaces are surfaces that are inclined at the same angle around the central axis of the first clutch portion 14c, and that when the engaging portion 14d and the engaged portion 14f are engaged, the multiple protrusions 14k of the engaging portion 14d and the multiple protrusions 14n of the engaged portion 14f are all in contact around the central axis of the first clutch portion 14c.

[Potentiometer]
The potentiometer 18 shown in Fig. 2(a) and Fig. 3(a) is an angle detection means for detecting the rotation angle of the output shaft 11a. For this purpose, a tenth gear (13j) is fixed to the rotation shaft of the potentiometer 18, and the tenth gear (13j) is arranged to mesh with an eighth gear (13h) attached to the output shaft 11a. Then, as shown in Fig. 6, the rotation angle of the output shaft detected by the potentiometer 18 is output to the control circuit 11b2 as an angle signal S5. The control circuit 11b2 processes the input angle signal S5 with a set algorithm (program), calculates an opening/closing command signal S1, and outputs it to the motor drive circuit 11b8. For example, when the rotation angle of the output shaft reaches a rotation angle corresponding to the set target opening degree, the control circuit 11b2 outputs an opening/closing command signal S1 for stopping the current supply to the motor drive circuit 11b8, and stops the drive of the main motor 17. The position detection means is not limited to a potentiometer, and a limit switch, which is a mechanical sensor, or a known magnetic sensor or optical sensor, such as a rotary encoder, can also be used.

[Using means]
The biasing means 15 of this embodiment is a spring unit made of a commonly used spiral spring. The spiral spring, which generates a torque (reaction force) acting to rotate the valve body in the valve closing direction when wound up, is connected to a rotating shaft 15a extending downward from the biasing means 15 as shown in FIG. 3(b), and is configured to be able to be wound up and unwound. A ninth gear (13i) is fixed to the rotating shaft 15a of the biasing means 15, which meshes with a seventh gear (13g) to which torque is transmitted via an eighth gear (13h) fixed to the output shaft 11a. As a result, when the seventh gear (13g) rotates due to the drive of the main motor 17 at the time of opening the valve, the eighth gear (13h) fixed to the meshing output shaft 11a rotates to rotate the output shaft 11a, and the rotation is transmitted to the ninth gear (13i), and the spiral spring of the biasing means 15 is wound up. As a result, torque is input to the biasing means 15 via the output shaft 11a which rotates to open the valve body, and a torque (reaction force) which acts to rotate the valve body in the valve closing direction is generated, biasing the valve body in the valve closing direction. Note that the above is for the case where the valve body is based on the open state, but if the valve closing state is based on the closed state, the biasing means 15 is configured to bias the valve body in the valve opening direction.

[brake]
As shown in Fig. 3(b), the brake 19 fixed to the lower surface of the lower case 11d is, for example, a viscous brake that rotates an impeller in a viscous fluid. An eleventh gear (13k) is fixed to the rotating shaft of the brake 19. When the engaging portion 14d of the clutch 14 is disengaged, the brake 19 is used to control the rotation speed of the sixth gear (13f) to the eighth gear (13g) and the output shaft 11a via the eleventh gear (13k).

[Control Means]
As shown in FIG. 3, the control means 11b of this embodiment is formed on a circuit board 11b. This circuit board 11b is supported by a support erected on the second base plate (11f) and is housed in an internal space formed by the upper case 11e and the lower case 11d. As shown in FIG. 6, the control means 11b is connected to a main motor 17 and a potentiometer 18, which are components that drive the electric actuator, and is also connected to an external power source 16 for energizing and a power outage monitoring unit 11b9 for monitoring a power outage. In addition, instrumentation signals such as a hot and cold water temperature signal from a temperature sensor of the air conditioning equipment and a steam flow rate signal are input to the control means 11b. The configuration of the control means 11b will be described in detail below.

For example, the external power source 16, which is a 24V AC power source, is connected to the DC power source circuit 11b1 that converts AC to DC, the power failure monitoring unit 11b9, and the motor drive circuit 11b8. Here, the solenoid actuator 14a is connected to the DC power source circuit 11b1. As a result, while the external power source 16 is energized (i.e., unless it is in a non-energized state such as a power failure), the solenoid actuator 14a operates, and the solenoid shaft 14b shown in FIG. 4 maintains a state in which the bush pin 14h is constantly pressed down, so that the clutch 14 is constantly connected. Also, as shown in FIG. 6, the main motor 17 can be driven by being energized from the external power source 16 via the motor drive circuit 11b8. Furthermore, the power failure monitoring unit 11b9 connected to the external power source 16 is configured to output a power failure signal (power failure start signal) S4 to the transmission circuit 11b7 when the power supply from the external power source 16 is cut off due to a power failure.

The control means 11b of this embodiment has a first control unit 11b3 composed of elements surrounded by a two-dot chain line and a second control unit 11b4 composed of elements surrounded by a dotted line. That is, the first control unit 11b3 is composed of a control circuit 11b2 and a motor drive circuit 11b8, which are connected to the DC power supply circuit 11b1 and are composed of a memory unit (memory) in which a control program and control data are stored and a central processing unit (CPU) that performs calculations based on the control program and control data. The second control unit 11b4 is composed of a charging unit 11b6 connected to the DC power supply circuit 11b1, an oscillation circuit 11b7 connected to the charging unit 11b6, and an electric motor drive circuit 11b8. The motor drive circuit 11b8, which is connected to the external power source 16 and the charging unit 11b6 described later, is a circuit that controls the current that drives the main motor 17 based on the opening/closing command signal S1 or the emergency opening/closing command signal S3 output from the control circuit 11b2 or the oscillator circuit 11b7, and is a circuit shared by the first control unit 11b3 and the second control unit 11b4.

The first control unit 11b3 is a circuit that controls the main motor 17 under normal conditions, that is, when electricity is supplied from the external power source 16. That is, when electricity is supplied, the rotation angle of the output shaft detected by the potentiometer 18 is output to the control circuit 11b2 as an angle signal S5, and the control circuit 11b2 processes the input angle signal S5 using a predetermined algorithm (program) and outputs an opening/closing command signal S1 calculated to control the opening and closing of the main motor 17 to the motor drive circuit 11b8, thereby controlling the rotation of the main motor 17. As a result, the output shaft 11a shown in Figures 2 and 3 rotates, and the position of the valve body is adjusted to a predetermined opening degree.

On the other hand, the second control unit 11b4 shown in FIG. 6 is a circuit that controls the main motor 17 in an emergency, that is, when the power supply from the external power source 16 is cut off (when it is not energized) due to a power outage or the like. That is, the charging unit 11b6 of the second control unit 11b4, which is a charging device such as a battery or a capacitor, is connected to the DC power supply circuit 11b1 and is charged from the DC power supply circuit 11b1 when the external power source 16 is energized. The oscillation circuit 11b7 is configured to receive the power outage signal S4 output from the power outage monitoring unit 11b9 when the power supply from the external power source 16 is cut off. When the power outage signal S4 is input, the oscillation circuit 11b7 converts the DC charged in the charging unit 11b6 to AC and outputs it to the motor drive circuit 11b8 as emergency drive power S2, and also outputs the emergency opening/closing command signal S3 to the motor drive circuit 11b8. As a result, the motor drive circuit 11b8 controls the current that drives the main motor 17 based on the emergency opening/closing command signal S3 output from the oscillator circuit 11b7, controls the rotation of the main motor 17, and operates the clutch so that F1 (the force that disengages the clutch) > F2 (the force that prevents the clutch from being disengaged), as shown in Figure 5 (b).

In this embodiment, as shown in FIG. 6, the second control unit 11b4 is equipped with a charging unit 11b6 and a transmitting circuit 11b7, and the main motor 17 is driven by the power stored in the charging unit 11b6. When the second control unit 11b4 is de-energized from the external power source 16, as shown in FIG. 5(b), the second control unit 11b4 is configured to rotate the first clutch unit 14c in the direction in which the pressing force W1 from the biasing means acts, i.e., in the same direction as the biasing direction of the biasing means.

More specifically, as shown in Fig. 6, the second control unit 11b4 has a charging unit 11b6. When the second control unit 11b4 is not energized, the charging unit 11b6 is used as a power source, and the first clutch unit 14c outputs an emergency opening/closing command signal (signal) S3 to the main motor 17 (via the motor drive circuit 11b8 in this embodiment) to rotate the main motor 17 in the direction opposite to the preset direction (i.e., the direction in which the pressing force W1 from the biasing means acts), as shown in Fig. 5(b), thereby rotating the main motor 17.

As shown in Fig. 5(b), the second control unit is preferably configured to output a signal to the main motor to rotate the first clutch unit 14c at a rotational acceleration Ac of 23 x 10 ⁶ deg/sec ² or more. By rotating the first clutch unit 14c at such a rotational acceleration Ac or more, the above-mentioned disconnection mechanism is effectively exerted, and the clutch 14 can be smoothly disconnected. The rotational acceleration Ac of the first clutch unit 14c can be confirmed by storing the change value and the change time of the angle signal S5 detected by the potentiometer 18 connected to the eighth gear (13j) in the control circuit 11b2, starting from the output time of the power failure signal S4 shown in Fig. 6.

In the electric actuator of the first embodiment, as shown in FIG. 5(b), the second control unit rotates the main motor in the reverse direction to rotate the first clutch portion 14c in the same direction as the biasing means, and operates the clutch so that F1>F2. However, as long as the first clutch portion 14c can rotate in the same direction as the biasing means, the configuration is not limited to the above, and the first clutch portion 14c may be configured to rotate in the reverse direction by, for example, an electric motor provided separately from the main motor, a spring unit similar to the biasing means, or a fluid-type (pneumatic or hydraulic) driving device.

<Electric actuator: Second embodiment>
An electric actuator according to a second embodiment of the present invention will be described with reference to Fig. 7. In Fig. 7, components similar to those of the electric actuator according to the first embodiment described with reference to Figs. 1 to 6 are given the same reference numerals, and detailed description thereof will be omitted (the same applies to the electric actuators according to the third to sixth embodiments described below).

The electric actuator 21 of the second embodiment shown in FIG. 7 is basically configured similarly to the electric actuator of the first embodiment. However,
As shown in FIG. 7B, in order to operate the clutch so that F1>F2, the second control unit is configured to rotate the second clutch unit 14e in a direction opposite to the biasing direction of the biasing means when de-energized.
The differences are as follows:

Specifically, as shown in Fig. 7(a), the electric actuator 21 of the second embodiment has an auxiliary motor 21a that generates a torque in the opposite direction to the direction of the biasing means 15. As with the electric actuator of the first embodiment, the second control unit has a charging unit and is configured to output a signal to the auxiliary motor 21a using the charging unit as a power source to rotate the auxiliary motor 21a in the direction in which the second clutch unit should rotate, i.e., in the opposite direction Bc (see Fig. 7(b)) to the direction of the biasing means when not energized, thereby rotating the auxiliary motor 21a. As with the electric actuator of the first embodiment, in order to smoothly disconnect the clutch 14, it is preferable that the second control unit is configured to output a signal to the main motor to rotate the second clutch unit 14e at a rotational acceleration Bc of 23 x 10 ⁶ deg/sec ² or more. This rotational acceleration Bc can be confirmed in the same manner as the rotational acceleration Ac of the first embodiment.

According to the flow control device having the electric actuator 21 of the second embodiment, as in the electric actuator of the second embodiment, when electricity is not being applied, the clutch is operated so that F1>F2, so that the clutch is smoothly disengaged and the valve body can quickly rotate in the valve closing direction when the valve is open, and in the valve opening direction when the valve is closed (the same applies to the electric actuators 31 to 61 of the third to sixth embodiments described below). Note that, as long as the second clutch portion can be rotated in the direction opposite to the direction of biasing by the biasing means when electricity is not being applied, the configuration of the electric actuator is not limited to the above, and for example, a spring unit or a fluid type (pneumatic or hydraulic) driving device similar to the biasing means may be applied instead of the auxiliary motor.

In the electric actuators of the first and second embodiments described above, the second control unit operates the clutch so that the first clutch unit or the second clutch unit rotates in a predetermined direction relative to the biasing direction of the biasing means, thereby disengaging the clutch, in order to reduce F2 out of the forces F1 and F2 acting on the clutch and achieve a state of F1>F2 (see FIG. 5(b)). In contrast, the electric actuators of the third to sixth embodiments described below increase F1, in order to achieve a state of F1>F2, in which the second control unit operates the clutch so that one of the engaging unit and the engaged unit, which are in an engaged state, moves away from the other, thereby disengaging the clutch.

<Electric actuator: third and fourth embodiments>
Electric actuators according to third and fourth embodiments of the present invention will be described with reference to Fig. 8. An electric actuator 31 according to the third embodiment shown in Fig. 8(a) is basically configured in the same manner as the electric actuator according to the first embodiment. However, in order to operate the clutch so that F1>F2,
(1) The clutch mechanism includes a separating means 31a for moving the first clutch portion 14c1 or the second clutch portion 14e so that one of the engaging portion 14d of the first clutch portion 14c1 and the engaged portion 14f of the second clutch portion 14e is separated from the other.
(2) The second control unit is different in that it is configured to operate the separating means 31a when de-energized to separate one of the engaging portion 14d and the engaged portion 14f, which are in an engaged state, from the other. As a result, in the electric actuator of the third embodiment, the second control unit operates the separating means 31a to separate one of the engaging portion 14d and the engaged portion 14f, which are in an engaged state, from the other, thereby increasing F1, achieving a state of F1>F2, and disengaging the clutch.

The electric actuator 31 of the third embodiment will be described in more detail. The separation means 31a of the electric actuator 31 is specifically a solenoid actuator. The solenoid actuator (separation means) 31a has a solenoid shaft 14b1, which is the drive unit, and an excitation coil (not shown) that raises and lowers (pushes and pulls) the solenoid shaft 14b1, and this excitation coil is a magnetic force generating unit that generates magnetic force when electricity is passed through it. The solenoid shaft (drive unit) 14b1 is connected to an annular protrusion 14t1 formed on the upper part of the first clutch portion 14c1 via its grip portion 14s1.

The control means of the third embodiment is basically the same as that of the first embodiment, but the charging section of the second control section is connected to the excitation coil of the solenoid actuator via a step-down circuit or the like that is arranged as necessary. When a power outage signal is input from the power outage monitoring section during non-energization, the second control section uses the charging section as a power source to operate the excitation coil (magnetic force generating section) of the solenoid actuator (separation means) 31a shown in FIG. 8(a), and indirectly forcibly raises (moves) the first clutch section 14c1 via the solenoid shaft (drive section) 14b1, thereby separating the engaged engaging section (one side) 14d from the engaged section (the other side) 14f, and disengages the clutch 34.

The electric actuator 31 of the third embodiment is an example in which the first clutch portion 14c1 is indirectly moved via the solenoid shaft (drive portion) 14b1 which rises and falls due to the magnetic force generated by the excitation coil (magnetic force generating portion) of the solenoid actuator (separating means) 31a. However, as in the electric actuator 41 of the fourth embodiment shown in FIG. 8(b), when the solenoid shaft 14b is in an unloaded (free) state during de-energization, the first clutch portion 14c2 may be directly moved (raised) by the magnetic force generated by the electromagnet (magnetic force generating portion) 41b of the separating means 41a using the charging portion as a power source, thereby separating the engaging portion 14d in the engaged state from the engaged portion 14f and disengaging the clutch 44. In this embodiment, it is preferable that the first clutch portion 14c2 is made of a magnetic material, and the shaft 14o2 through which the first clutch portion 14c2 is inserted is made of a non-magnetic material.

<Electric actuator: fifth and sixth embodiments>
An electric actuator according to a fifth and sixth embodiment of the present invention will be described with reference to Fig. 9. The electric actuator 51 according to the fifth embodiment shown in Fig. 9 is basically configured similarly to the electric actuator according to the first embodiment.
(1) The separating means 51a includes a magnetic force generating unit 14q3 that generates a magnetic force when energized.
(2) The extending member 14p3 is disposed between the engaging portion 14d and the engaged portion 14f and extends due to a magnetic force.
(3) The second control unit is configured to operate the magnetic force generating unit 14q3 using the charging unit as a power source when not energized, and to extend the extending member 14p3 to separate one of the engaging portion 14d and the engaged portion 14f, which are in an engaged state, from the other. Hereinafter, the electric actuator 51 of the fifth embodiment will be described in detail.

Between the engaging portion 14d and the engaged portion 14f of the electric actuator 51 of the fifth embodiment, there are disposed a compression coil spring 14g3, which is an elastic member, and an extension member 14p3, which extends by magnetic force in a direction along the central axis J. Specifically, in the radial center of each of the engaging portion 14d and the engaged portion 14f, approximately cylindrical recesses 14u3 and 14v3 are formed, and in the opposing engaging portion 14d and engaged portion 14f, a storage portion 14w3 is formed by two recesses. Then, in the radial direction, the compression coil spring 14g3 is disposed outside the storage portion 14w3, and the approximately annular extension member 14p3 is disposed concentrically inside the compression coil spring 14g3. Note that there is no particular limitation on the extension member 14p3 as long as it is a member that extends by magnetic force, and for example, an elastic member in which magnetic powder is dispersed or an elastic member having a magnetic piece at the upper end can be used. Furthermore, if the compression coil spring 14g3 itself is made of a magnetic material, it can serve as both the elastic member 14g3 and the tension member 14q3.

The magnetic force generating unit 14q3, which generates a magnetic force when electricity is applied to extend the extension member 14p3, is arranged in the hollow portion 14r3 of the substantially cylindrical shaft 14o3 through which the first clutch portion 14c and the second clutch portion 14e are inserted, so that the magnetic force generating unit 14q3 is at approximately the same height as the extension member 14p3 in the direction along the central axis J. There are no particular limitations on the magnetic force generating unit 14q3 as long as it is a device that generates a magnetic force when electricity is applied, and for example, a well-known electromagnet can be applied. Alternatively, the magnetic force generating unit may be composed of a permanent magnet, and a separating means may be configured so that the permanent magnet can rise and fall within the hollow portion 14r3, and if necessary, the magnetic force generating unit may be configured to move to approximately the same height as the extension member 14p3.

The control means of the fifth embodiment is basically the same as that of the first embodiment, but the charging unit of the second control unit is connected to the magnetic force generating unit 14q3 shown in FIG. 9 via a step-down circuit or the like that is arranged as necessary. When a power outage signal is input from the power outage monitoring unit during non-energization, the second control unit is configured to operate the magnetic force generating unit 14q3 using the charging unit as a power source, extend the extension member 14p3, and raise (move) the first clutch unit 14c, thereby separating the engaging unit (one side) 14d, which is in an engaged state, from the engaged unit (the other side) 14f and disengage the clutch 54.

The electric actuator 31 of the fifth embodiment is an example in which the magnetic force generated by the magnetic force generating unit 14q3 extends the extension member 14p3 and moves the first clutch unit 14c1. However, as in the electric actuator 61 of the sixth embodiment, the magnetic force generating unit 14q3 may be replaced with a heat generating unit 14q4 that generates heat when electricity is applied, and the extension member 14p3 that extends by magnetic force may be replaced with an extension member 14p4 that extends by heating. In this embodiment, when a power outage signal is input from the power outage monitoring unit during non-energization, the second control unit uses the charging unit as a power source to operate (generate heat) the heat generating unit 14q4, extend the extension member 14p4, and raise (move) the first clutch unit 14c, thereby separating the engaging unit 14d, which is in an engaged state, from the engaged unit 14f and disengaging the clutch 54.

The following describes examples of the present invention, but the present invention is not limited to the following examples.

A flow control device 10 was manufactured incorporating a Hitachi Metals ball valve (type: SCUH) as the valve portion 12 shown in Fig. 1. The specifications of the main components of the electric actuator 11 according to the first embodiment, which is incorporated in the flow control device 10 and shown in Fig. 2 and Fig. 3, are as follows:
Main motor 17: Synchronous motor (rated torque 0.00118N・m, 500/600rpm (50Hz/60Hz))
First gear (13a) Module (m): 0.5, Number of teeth (Z): 10
Second Gear (13b) Large Diameter Gear Module (m): 0.5, Number of Teeth (Z): 23
Small diameter gear Module (m): 0.5, Number of teeth (Z): 15
Third gear (13c) Large diameter gear Module (m): 0.5, Number of teeth (Z): 26
Small diameter gear Module (m): 0.5, Number of teeth (Z): 11
4th Gear (13d) Large Diameter Gear Module (m): 0.5, Number of Teeth (Z): 33
Small diameter gear Module (m): 0.6, Number of teeth (Z): 11
5th Gear (13e) Large Diameter Gear Module (m): 0.6, Number of Teeth (Z): 50
Small diameter gear Module (m): 0.8, Number of teeth (Z): 28
6th Gear (13f) Large Diameter Gear Module (m): 0.8, Number of Teeth (Z): 53
Small diameter gear Module (m): 0.8, Number of teeth (Z): 13
7th Gear (13g) Large Diameter Gear Module (m): 0.8, Number of Teeth (Z): 52
Small diameter gear Module (m): 1, Number of teeth (Z): 15
8th Gear (13h) Module (m): 1, Number of Teeth (Z): 52
9th Gear (13i) Module (m): 1, Number of Teeth (Z): 11
Spring unit (spring constant 0.25 N.m/turn, 0.75 N.m when wound, 0.6 N.m when assembled)

Using the electric actuator described above, the valve element 12b shown in Fig. 1 was fully opened, and then the power supply from the external power source ^was manually cut off to de-energize it, and it was confirmed whether the valve element was fully closed by the biasing means in two cases: when the rotational acceleration Ac of the first clutch portion 14c shown in Fig. 5(b) was controlled by the second control portion 11b4 shown in Fig. 6 to be ²³ x ¹⁰⁶ deg/sec2, and when it was controlled to be 18 x 106 deg/ ^sec2 . In the former case, the clutch was disengaged and the valve element was fully closed immediately after de-energization, but in the latter case, the clutch was not disengaged and the valve element remained fully open.

11 (21 to 61) Electric actuator 11a Output shaft 11b Circuit board (control means)
11b1 DC power supply circuit 11b2 Control circuit 11b3 First control unit 11b4 Second control unit 11b6 Charging unit 11b7 Oscillation circuit 11b8 Motor drive circuit 11b9 Power failure monitoring unit 11c First base plate 11d Lower case 11e Upper case 11f Second base plate 12 Valve unit 12a Valve box 12b Valve body 12c Seat ring 12d Flow path 12e Valve stem 12f Through hole unit 13a to 13k First gear to eleventh gear 13m Transmission means 14 Clutch 14a Solenoid actuator 14b Solenoid shaft 14c First clutch unit 14d Engagement unit 14e Second clutch unit 14f Engaged unit 14g Elastic member 14h Bush pin 14i Tooth portion 14j Tooth portion 14k Convex portion 14l Concave portion 14m Concave portion 14n Convex portion 14o Shaft 15 Pressing means 15a Rotating shaft 16 External power source 17 Main motor 17a Rotating shaft 18 Potentiometer 19 Brake

Claims (14)

An electric actuator for opening and closing a valve of a flow control device,
a main motor having a rotating shaft, which generates a holding torque when not energized;
an output shaft connected to the valve body;
a biasing means having a rotating shaft for biasing the valve body in a valve opening direction or a valve closing direction by inputting torque via the output shaft;
A transmission means having N (N≧2) gears for transmitting the torque of the main motor and the biasing means to the output shaft;
A control means for controlling the operation of the main motor,
A clutch is incorporated in the rotating shaft of the main motor, the output shaft, the rotating shaft of the biasing means, or the transmission means, which is configured to be connected when energized and to be disconnected by a force F1 when not energized,
Furthermore, a force F2 that prevents the clutch from being disengaged is applied to the clutch, the force F2 being generated by the torque transmitted from the biasing means to the clutch,
The control means has a first control unit and a second control unit,
The first control unit outputs a signal to the main motor to rotate the main motor in a direction in which the valve body closes or opens, thereby rotating the main motor,
The electric actuator, wherein the second control unit is configured to operate the clutch so that F1>F2 is satisfied when the second control unit is not energized. The electric actuator according to claim 1 , wherein the clutch is incorporated in at least one of the gears constituting the transmission means. the clutch includes a first clutch portion connected to the main motor and having an engaging portion, and a second clutch portion connected to the biasing means and having an engaged portion that engages with the engaging portion,
3. The electric actuator according to claim 1, wherein the second control section is configured such that, when de-energized, the first clutch section rotates in the same direction as the biasing direction of the biasing means. The second control unit has a charging unit,
4. The electric actuator according to claim 3, wherein the charging unit is used as a power source, and when de-energized, the charging unit outputs a signal to the main motor to rotate the main motor in a direction in which the first clutch unit should rotate, thereby rotating the main motor. the clutch includes a first clutch portion connected to the main motor and having an engaging portion, and a second clutch portion connected to the biasing means and having an engaged portion that engages with the engaging portion,
The electric actuator according to claim 1 or 2, wherein the second control section is configured such that, when de-energized, the second clutch section rotates in a direction opposite to a direction of biasing by the biasing means. a sub-motor that generates a torque in a direction opposite to the direction of the biasing means,
The second control unit has a charging unit,
6. The electric actuator according to claim 5, wherein the charging unit is used as a power source, and when de-energized, the charging unit outputs a signal to the secondary motor to rotate the secondary motor in a direction in which the second clutch unit should rotate, thereby rotating the secondary motor. 7. The electric actuator according to claim ⁶ , wherein the second control unit is configured to output, to the main motor or the auxiliary motor, a signal that causes the first clutch unit or the second clutch unit to rotate at a rotational acceleration of ²³ ×10 deg/sec2 or more . the first clutch portion is substantially cylindrical in shape and has the engaging portion at an end thereof,
the second clutch portion is substantially cylindrical and has the engaged portion at an end thereof,
The first clutch portion and the second clutch portion are coaxially arranged,
The engaging portion has a plurality of recesses and protrusions arranged at predetermined intervals around a central axis of the first clutch portion,
The engaged portion is formed with a plurality of recesses and protrusions around a central axis of the second clutch portion, the recesses and protrusions being formed to engage with the plurality of recesses and protrusions of the engaging portion,
a plurality of protruding portions of the engaging portion and the engaged portion each have a shape in which a tip thereof is tapered in a direction along a central axis of the first clutch portion, and both side surfaces of the protruding portions are inclined at the same angle around the central axis of the first clutch portion;
The electric actuator according to any one of claims 3 to 7, characterized in that when the engaging portion and the engaged portion are engaged, the multiple convex portions of the engaging portion and the multiple convex portions of the engaged portion are all in contact around the central axis of the first clutch portion . the clutch includes a first clutch portion connected to the main motor and having an engaging portion, and a second clutch portion connected to the biasing means and having an engaged portion that engages with the engaging portion,
Furthermore, the electric actuator has a separating means for moving the first clutch portion or the second clutch portion so that one of the engaging portion and the engaged portion is separated from the other,
The electric actuator according to any one of claims 1 or 2, characterized in that the second control unit is configured to operate the separating means when not energized, thereby separating one of the engaging portion and the engaged portion, which are in an engaged state, from the other. The separating means is
a magnetic force generating unit that generates a magnetic force when energized;
a drive unit that is connected to the first clutch unit or the second clutch unit and is driven by the magnetic force generating unit, the drive unit being disposed as necessary;
Furthermore, the second control unit has a charging unit,
The electric actuator according to claim 9, characterized in that the second control unit is configured to operate the magnetic force generating unit using the charging unit as a power source when not energized, and to move the first clutch unit or the second clutch unit directly or indirectly via the drive unit, thereby separating one of the engaging unit and the engaged unit, which are in an engaged state, from the other. The separating means has a magnetic force generating unit that generates a magnetic force when energized,
the electric actuator has an extension member disposed between the engaging portion and the engaged portion and extending by a magnetic force;
Furthermore, the second control unit has a charging unit,
The electric actuator according to claim 9, characterized in that the second control unit is configured to operate the magnetic force generating unit using the charging unit as a power source when not energized, and to extend the extension member, thereby separating one of the engaging portion and the engaged portion, which are in an engaged state, from the other. The separating means has a heat generating portion that generates heat when energized,
the electric actuator has an expansion member that is disposed between the engaging portion and the engaged portion and expands when heated,
Furthermore, the second control unit has a charging unit,
The electric actuator according to claim 9, characterized in that the second control unit is configured, when not energized, to operate the heating unit using the charging unit as a power source and extend the extension member, thereby separating one of the engaging unit and the engaged unit, which are in an engaged state, from the other. The electric actuator according to any one of claims 2 to 12, characterized in that the clutch is incorporated in a gear with a TB/TA ratio of 0.2 or less, where TA is the torque generated by the biasing means and TB (B = 1 to N) is the torque generated in each of the N gears constituting the transmission means by the torque being transmitted from the biasing means via the output shaft. A flow control device comprising an electric actuator according to any one of claims 1 to 13.

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