JP4008781B2 - Electric servo actuator for adjusting water quantity of water turbine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electric servo actuator for adjusting the amount of water in a turbine used for a guide vane driving device for a power generation turbine.
[0002]
[Prior art]
Conventionally, as this type of electric servo actuator, for example, there is one disclosed in Japanese Patent No. 2502066. As shown in FIG. 4, a cylindrical actuator housing 1 and a brushless electric motor provided in the actuator housing 1 2, a thrust conversion mechanism 3 that is moved back and forth by driving the electric motor 2, and a trunnion 4 as a support base that supports the actuator housing 1 via a universal joint.
[0003]
The electric motor 2 includes a stator 5 fixed to the actuator housing 1 and a rotor 6 made of a permanent magnet rotatably supported in the stator 5.
[0004]
The thrust converting mechanism 3 includes a screw shaft body 9 having a ball screw portion 9 a and a nut body 10 formed of a ball nut screwed to the ball screw portion 9 a so as to be freely advanced and retracted. A yoke 7 fixed to the rotor 6 is attached to the yoke 7. The nut body 10 is fixed. On both sides of the electric motor 2, a yoke 7 is rotatably supported by the actuator housing 1 via a radial ball bearing 11 and a thrust roller bearing 12.
[0005]
One end portion of the screw shaft body 9 protrudes from the actuator housing 1, and a connection fitting 14 provided at the tip thereof is connected to the gate shaft arm 16 via a link 15.
[0006]
When the nut body 10 is rotated in the forward / reverse direction by the forward / reverse rotation operation of the rotor 6 driven by the electric motor 2, the ball screw portion 9a screwed to the nut body 10 is moved forward and backward in the axial direction. In addition, the screw shaft body 9 is moved in and out in the axial direction thereof, the gate shaft arm 16 is rotated through the coupling fitting 14 and the link 15, and the gate shaft 17 is rotated. It was structured to open and close the guide vanes.
[0007]
[Problems to be solved by the invention]
However, according to the electric servo actuator of the conventional structure disclosed in the above publication, the thrust roller bearing 12 is arranged at the end opposite to the position where the screw shaft body 9 protrudes outside the actuator housing 1, and in the vicinity thereof, The actuator housing 1 is supported by the trunnion 4, and the distance between the thrust member 12 and the trunnion 4 from the coupling fitting 14 that receives the load thrust from the water wheel side is long.
[0008]
As described above, when the distance between the connecting metal fitting 14 and the thrust roller bearing 12 or the trunnion 4 is long, that is, when the distance between the fulcrums is long, the deflection generated by the self weight or load thrust on the screw shaft body 9 or the like becomes large. If the deflection is large, the thrust generated by the electric servo actuator cannot be transmitted straight to the counterpart member, resulting in a problem of poor output efficiency.
[0009]
In order to reduce the deterioration of the thrust output efficiency due to such deflection, it is necessary to reinforce the structural member between the fulcrums to suppress the deflection.
[0010]
However, the strengthening of the structural member between the fulcrums causes an increase in the weight of the electric servo actuator, which causes a problem that it takes time to carry and install the electric servo actuator, which is inconvenient to handle.
[0011]
SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide an electric servo actuator for adjusting the amount of water in a turbine wheel that reduces deflection and reduces weight.
[0012]
[Means for Solving the Problems]
The technical means for achieving the above object includes an electric motor comprising a stator fixed in an actuator housing , a rotor rotatably supported in the stator, and a nut fixedly attached to and fixed to the rotor. A thrust conversion mechanism comprising a body and a screw shaft body that is threadably engaged with the nut body and has one end protruding from the actuator housing, and receives a load thrust acting on the screw shaft body and a thrust bearing, in the water wheel water adjustment electric servo actuator the threaded shaft body is projecting and retracting operation in the axial center direction by rotation of the nut body caused by the rotation of the rotor, substantially longitudinal middle of the actuator housing The thrust bearing is provided in the portion, and the nut body portion is rotatably supported by the thrust bearing, On one side of the last bearing, the screw shaft body is disposed so as to protrude out of the actuator housing, the electric motor is disposed in the actuator housing located on the other side of the thrust bearing, and a fulcrum portion of a support base that supports the actuator housing is provided. The thrust bearing portion is rotatably disposed.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIGS. 1 to 3, an electric servo actuator 20 for adjusting the amount of water in a turbine wheel is a so-called cylindrical actuator housing 21 and an actuator housing 21 as described above. A brushless electric motor 22 provided in the motor, a thrust conversion mechanism 23 that is operated to be retracted by driving the electric motor 22, and a support base 25 that supports the actuator housing 21 via a universal joint 24 are provided.
[0014]
The electric motor 22 includes a stator 26 fixed in the actuator housing 21 and a cylindrical rotor 27 made of a permanent magnet rotatably supported in the stator 26.
[0015]
The thrust converting mechanism 23 includes a screw shaft body 29 having a roller screw portion 29a, and a nut body 30 formed of a roll nut screwed to the roller screw portion 29a so as to be freely advanced and retracted, and one axial side surface side of the rotor 27 The nut body 30 is attached and fixed to the nut support cylinder portion 31 attached and fixed to the nut. A support cylinder 32 is also attached and fixed to the other side surface in the axial direction of the rotor 27, and the outer peripheral surface of the nut support cylinder 31 and the outer peripheral surface of the support cylinder 32 are respectively thrust roller bearings as thrust bearings. 34 and a radial ball bearing 35 are rotatably supported on the actuator housing 21.
[0016]
At this time, the thrust roller bearing 34 is disposed at a substantially intermediate portion in the longitudinal direction of the actuator housing 21, and the radial ball bearing 35 is disposed at the longitudinal end portion of the actuator housing 21.
[0017]
Also, one end of the screw shaft body 29 protrudes from the actuator housing 21, and a connection fitting 37 attached to the tip of the screw shaft body 29 is connected to the gate shaft arm via a link or the like.
[0018]
The one end portion of the screw shaft body 29 is supported by one end portion of the actuator housing 21 so as to be freely movable in the axial direction via a bearing 39 or the like.
[0019]
In addition, a sensor box 40 having a control mechanism for controlling the amount of withdrawal and withdrawal of the screw shaft body 29 is attached to the other end portion of the actuator housing 21 that supports the support cylinder portion 32.
[0020]
The actuator housing 21 is supported by the support base 25 via a universal joint 24 at a thrust roller bearing 34 portion where the nut body 30 is rotatably supported.
[0021]
The electric servo actuator 20 in the present embodiment is configured as described above, and when the nut body 30 is rotated forward and backward by the forward / reverse rotation operation of the rotor 27 by driving the electric motor 22, it is screwed into the nut body 30. The roller screw portion 29a is moved forward and backward in the axial direction, and the screw shaft body 29 is moved out and retracted in the axial direction, and the gate shaft arm is rotated through the connecting bracket 37 and the link. By operating and turning the gate shaft, the guide vanes for the water turbine are opened and closed, and the water amount of the water turbine is adjusted.
[0022]
According to the present embodiment, the nut body 30 portion is rotatably supported by the thrust roller bearing 34 provided at the substantially middle portion in the longitudinal direction of the actuator housing 21, and the actuator housing 21 is supported by the thrust roller bearing 34 portion. Since it is supported by the support base 25 via the universal joint 24, it has a structure that receives its own weight and load thrust at two points of the connecting bracket 37 and the support base 25 connected to the water wheel side.
[0023]
At this time, since the electric motor 22 is disposed on the opposite side of the thrust shaft bearing 29 from the side of the screw shaft body 29 that protrudes outside the actuator housing 21, the connecting bracket 37 and the thrust roller are disposed. The distance between the bearing 34 and the support base 25, that is, the distance L between fulcrums can be made shorter.
[0024]
Accordingly, since the distance L between the fulcrums can be made shorter, the deflection due to its own weight and the deflection due to the load thrust in the meantime can be effectively reduced , and the actuator housing 21 is supported by the thrust roller bearing 34 portion via the universal joint 24. 25, the thrust generated by the electric servo actuator 20 can be transmitted to the counterpart member substantially straight, and the output efficiency can be improved.
[0025]
In addition, the motor 22 portion and the sensor box 40 portion arranged on the opposite side of the connecting metal fitting 37 side with respect to the thrust roller bearing 34 do not receive the load thrust acting on the screw shaft body 29, and thus support them. The actuator housing 21 that has the minimum required strength can be thinned, and the electric servo actuator 20 as a whole can be reduced in weight. Further, the weight reduction of the electric servo actuator 20 has an advantage that the electric servo actuator 20 can be easily handled during transportation and installation.
[0026]
In the present embodiment, the thrust conversion mechanism 23 has a structure including a screw shaft body 29 having a roller screw portion 29a and a nut body 30 made of a roll nut. However, the screw shaft body 29 and the nut having a ball screw structure are shown. The structure which consists of the body 30 may be sufficient, and is not limited to the structure of embodiment.
[0027]
Moreover, although the thrust roller bearing 34 is shown as a thrust bearing, a thrust ball bearing may be sufficient and it is not limited to the structure of embodiment.
[0028]
【The invention's effect】
As described above, according to the electric servo actuator for adjusting the amount of water in the turbine wheel according to the present invention, the thrust bearing is provided at the substantially middle portion in the longitudinal direction of the actuator housing , and the nut body portion of the thrust conversion mechanism can be freely rotated by the thrust bearing. A support base that supports and supports the actuator housing in which the screw shaft body of the thrust conversion mechanism protrudes outside the actuator housing on one side of the thrust bearing and the electric motor is arranged in the actuator housing located on the other side of the thrust bearing. The fulcrum part is rotatably arranged on the thrust bearing part, and the distance between the part connected to the turbine wheel and the thrust bearing or the support base can be made shorter, and the distance between the fulcrum parts can be made shorter. Since it can be configured, deflection due to its own weight and deflection due to load thrust in the meantime are effectively reduced. Can, the thrust generated by an electric servo actuator can be substantially straight transmission to the other member, there is an advantage that the output efficiency can be improved.
[0029]
In addition, since the portion where the electric motor is disposed does not receive the load thrust acting on the screw shaft body, the actuator housing that supports these needs only to have the necessary minimum strength and can be thinned. Thus, the overall weight of the electric servo actuator can be reduced. Further, the weight reduction of the electric servo actuator has an advantage that the electric servo actuator can be easily handled during transportation and installation.
[Brief description of the drawings]
FIG. 1 is a sectional front view of an electric servo actuator for adjusting the amount of water in a turbine according to an embodiment of the present invention.
FIG. 2 is a plan view of the same.
FIG. 3 is a left side view in FIG. 1;
FIG. 4 is a sectional front view showing a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 20 Electric servo actuator 21 Actuator housing 22 Electric motor 23 Thrust conversion mechanism 24 Universal joint 25 Support stand 26 Stator 27 Rotor 29 Screw shaft body 29a Roller screw part 30 Nut body 34 Thrust roller bearing 37 Connecting metal fitting

Claims (1)

An electric motor comprising a stator fixed in the actuator housing and a rotor rotatably supported in the stator;
A thrust conversion mechanism comprising a nut body that is attached and fixed to the rotor so as to be integrally rotatable, and a screw shaft body that is threadably engaged with the nut body and has one end projectingly disposed outside the actuator housing;
A thrust bearing for receiving a load thrust acting on the screw shaft body,
In the electric servo actuator for adjusting the amount of water in the turbine wheel in which the screw shaft body is operated to move in and out of the axial direction by the rotation of the nut body accompanying the rotation of the rotor,
The thrust bearing is provided in a substantially middle portion in the longitudinal direction of the actuator housing, and the nut body portion is rotatably supported by the thrust bearing,
On one side of the thrust bearing, the screw shaft body is disposed to protrude outside the actuator housing, and the electric motor is disposed in the actuator housing located on the other side of the thrust bearing,
An electric servo actuator for adjusting the amount of water in a turbine, wherein a fulcrum portion of a support for supporting the actuator housing is rotatably disposed in a thrust bearing portion.

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