JP2004080862A - Electrically-operated servo actuator for regulating water quantity in water wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrically-operated servo actuator for regulation of the quantity of water in a water wheel which realizes reducition in flexion and weight reduction. <P>SOLUTION: The electrically-operated servo actuator 20 is equipped with a motor 22 consisting of a stator 26 and a rotor 27, a thrust-converting mechanism 23 consisting of a nut body 30 attached to the rotor 27, capable of integral rotation and a screw shaft 29 screwed in the nut body 30, and a thrust roller bearing 34, which bears the load thrust working on the screw shaft 29. The thrust roller bearing 34 is installed in substantially the middle part in longitudinal direction of an actuator casing 21, and the thrust roller bearing 34 rotatably supports the section of the nut body 30. The screw shaft 29 is projected on one side of the thrust roller bearing 34, and the motor 22 is arranged on the other side of the thrust roller bearing 34, and the fulcrum of the support stand 25 for supporting an actuator housing 21 is arranged at the section of the thrust roller bearing 34. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electric servoactuator for adjusting a water quantity of a water turbine used for a guide vane driving device for a water turbine.
[0002]
[Prior art]
Conventionally, as this kind of electric servo actuator, for example, there is one disclosed in Japanese Patent No. 2502066, and 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 out and back by driving the electric motor 2, and a trunnion 4 as a support 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 conversion mechanism 3 includes a screw shaft body 9 having a ball screw portion 9a, and a nut body 10 formed of a ball nut screwed into the ball screw portion 9a so as to be able to advance and retreat. The nut body 10 is fixed. On both sides of the electric motor 2, the 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 of the screw shaft 9 projects out of the actuator housing 1, and a connection fitting 14 provided at the end thereof is connected to a gate shaft arm 16 via a link 15.
[0006]
When the nut body 10 is rotated forward and reverse by the forward and reverse rotation 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 operated to move back and forth in the axial direction thereof, and the gate shaft arm 16 is rotated and the gate shaft 17 is rotated via the connection fitting 14 and the link 15, whereby the water wheel is used. It was designed to open and close the guide vanes.
[0007]
[Problems to be solved by the invention]
However, according to the electric servo actuator having the conventional structure disclosed in the above publication, the thrust roller bearing 12 is disposed at the end opposite to the position where the screw shaft body 9 protrudes out of the actuator housing 1, and in the vicinity thereof, The structure is such that the actuator housing 1 is supported by the trunnion 4, and the distance between the thrust roller bearing 12 and the trunnion 4 is long from the connection fitting 14 which receives the load thrust from the turbine wheel side.
[0008]
As described above, when the distance between the connection 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 own weight or the load thrust on the screw shaft body 9 becomes large. If the deflection is large, the thrust generated by the electric servo actuator cannot be transmitted straight to the mating member, and the output efficiency is poor.
[0009]
Then, in order to reduce the deterioration of the thrust output efficiency due to such bending, it is necessary to suppress the bending by strengthening the structural members between the fulcrums.
[0010]
However, the strengthening of the structural members between the fulcrums causes an increase in the weight of the electric servo actuator, and it takes time to carry out and install the electric servo actuator, which causes a problem that handling is inconvenient.
[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 water amount adjustment of a water turbine with reduced deflection and light weight.
[0012]
[Means for Solving the Problems]
Technical means for achieving the above object include an electric motor including a stator fixed in an actuator casing, a rotor rotatably supported in the stator, and a nut fixed to the rotor so as to be integrally rotatable. A thrust conversion mechanism comprising a body, and a screw shaft body which is screwed to the nut body so as to be able to advance and retreat freely, and one end of which protrudes outside the actuator housing, and receives a load thrust acting on the screw shaft body. A thrust bearing, wherein the rotation of the nut body accompanying the rotation of the rotor causes the screw shaft body to move in and out of the axial direction thereof. The portion is provided with the thrust bearing, the nut body portion is rotatably supported by the thrust bearing, On one side of the thrust bearing, the screw shaft body is arranged to protrude out of the actuator housing, the electric motor is arranged in the actuator housing located on the other side of the thrust bearing, and a fulcrum of a support base for supporting the actuator housing is provided. , Located at the thrust bearing portion.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the drawings. As shown in FIGS. 1 to 3, a water turbine water volume adjusting electric servo actuator 20 includes a so-called cylindrical actuator housing 21 and an actuator housing 21. The motor includes a brushless electric motor 22 provided therein, a thrust conversion mechanism 23 that is operated to move out and out by driving the electric motor 22, and a support 25 that supports the actuator housing 21 via a universal joint 24.
[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 conversion mechanism 23 includes a screw shaft 29 having a roller screw portion 29a, and a nut body 30 formed of a roll nut screwed into the roller screw portion 29a so as to be able to advance and retreat. The nut body 30 is attached and fixed to the nut support cylindrical portion 31 attached and fixed to the nut. A support cylinder 32 is also fixedly mounted on the other side of the rotor 27 in the axial direction, and the outer peripheral surface of the nut support cylinder 31 and the outer peripheral surface of the support cylinder 32 are each a thrust roller bearing as a thrust bearing. It is rotatably supported by the actuator housing 21 via the radial ball bearings 34 and 35.
[0016]
At this time, the thrust roller bearing 34 is disposed at a substantially middle portion in the longitudinal direction of the actuator housing 21, and the radial ball bearing 35 is disposed at a longitudinal end of the actuator housing 21.
[0017]
Further, one end of the screw shaft body 29 is arranged so as to protrude outside the actuator housing 21, and a connection fitting 37 attached to the end thereof is connected to the gate shaft arm via a link or the like.
[0018]
The one end of the screw shaft body 29 is supported by one end of the actuator housing 21 via a bearing 39 or the like so as to be freely movable in the axial direction.
[0019]
Further, a sensor box 40 having a control mechanism for controlling the amount of protrusion and retraction of the screw shaft body 29 is mounted on the other end of the actuator housing 21 that supports the support cylinder 32.
[0020]
The actuator housing 21 is supported by a support 25 via a universal joint 24 at a portion of a thrust roller bearing 34 where the nut body 30 is rotatably supported.
[0021]
The electric servo actuator 20 according to the present embodiment is configured as described above. When the forward / reverse rotation operation of the rotor 27 driven by the electric motor 22 causes the forward / reverse rotation of the nut body 30, the electric servo actuator 20 is screwed into the nut body 30. The roller screw portion 29a is moved forward and backward along the axial direction, and the screw shaft body 29 is operated to move back and forth in the axial direction, and the gate shaft arm is rotated via the connecting bracket 37 and the link. By operating and rotating the gate shaft, the guide vane for the water wheel is opened and closed, and the water amount of the water wheel is adjusted.
[0022]
According to the present embodiment, the nut body 30 is rotatably supported by the thrust roller bearing 34 provided at a 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. Since it is supported by the support 25 via the universal joint 24, the structure is such that it receives its own weight and the load thrust at two points, the connecting bracket 37 connected to the water wheel and the support 25.
[0023]
At this time, since the electric motor 22 is disposed on the side opposite to the side of the screw shaft body 29 protruding outside the actuator housing 21 with respect to the thrust roller bearing 34, the connection bracket 37 and the thrust roller The distance between the bearing 34 and the support 25, that is, the distance L between fulcrums can be made shorter.
[0024]
Therefore, 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 during that period can be effectively reduced, and the thrust generated by the electric servo actuator 20 can be transmitted almost straight to the mating member. There is an advantage that the output efficiency can be improved.
[0025]
In addition, the motor 22 and the sensor box 40 disposed on the side opposite to the connection fitting 37 with respect to the thrust roller bearing 34 do not receive the load thrust acting on the screw shaft body 29, and therefore support them. The actuator housing 21 need only have a minimum necessary strength, and can be made thinner, and the electric servo actuator 20 can be made lighter as a whole. The weight reduction of the electric servo actuator 20 has an advantage that the electric servo actuator 20 can be easily handled at the time of transportation and installation.
[0026]
In the present embodiment, the thrust conversion mechanism 23 has a structure including the screw shaft 29 having the roller screw portion 29a and the nut body 30 composed of a roll nut. The structure including the body 30 may be used, and is not limited to the structure of the embodiment.
[0027]
Further, although the thrust roller bearing 34 is shown as the thrust bearing, it may be a thrust ball bearing, and is not limited to the structure of the embodiment.
[0028]
【The invention's effect】
As described above, according to the electric servo actuator for water turbine water amount adjustment of the present invention, the thrust bearing is provided at the substantially middle portion in the longitudinal direction of the actuator casing, and the nut body portion of the thrust conversion mechanism is rotatable by the thrust bearing. A support base for supporting the actuator housing, wherein the screw shaft body of the thrust conversion mechanism is arranged to protrude out of 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 portion is disposed on the thrust bearing portion, and the portion connected to the turbine side and the thrust bearing or the support base can be configured to have a shorter mutual distance and the fulcrum distance can be configured to be shorter. In the meantime, deflection due to its own weight and deflection due to load thrust can be effectively reduced. The thrust generated by the turbo 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 motor is disposed does not receive the load thrust acting on the screw shaft, the actuator housing that supports them need only have the minimum necessary strength, and the thickness can be reduced. In addition, the overall weight of the electric servo actuator can be reduced. In addition, there is an advantage that the weight reduction of the electric servo actuator facilitates the handling of the electric servo actuator at the time of transportation and installation.
[Brief description of the drawings]
FIG. 1 is a cross-sectional front view of an electric servo actuator for water amount adjustment of a water 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 of FIG.
FIG. 4 is a sectional front view showing a conventional example.
[Explanation of symbols]
Reference Signs List 20 electric servo actuator 21 actuator housing 22 electric motor 23 thrust conversion mechanism 24 universal joint 25 support base 26 stator 27 rotor 29 screw shaft body 29a roller screw section 30 nut body 34 thrust roller bearing 37 connection fitting

Claims (1)

An electric motor including a stator fixed in an actuator casing and a rotor rotatably supported in the stator;
A thrust conversion mechanism comprising a nut body fixedly attached to the rotor so as to be rotatable integrally with the rotor, and a screw shaft body which is screwed to the nut body so as to be able to advance and retreat, and one end of which is arranged to protrude outside the actuator housing;
A thrust bearing for receiving a load thrust acting on the screw shaft body,
An electric servo actuator for water turbine water volume adjustment in which the screw shaft body is operated to retract in the axial direction by rotation of the nut body with rotation of the rotor,
The thrust bearing is provided at a substantially middle portion in the longitudinal direction of the actuator casing, and the nut body portion is rotatably supported by the thrust bearing,
On one side of the thrust bearing, the screw shaft body is arranged to protrude outside the actuator housing, and the electric motor is arranged in an actuator housing located on the other side of the thrust bearing,
An electric servo actuator for water amount adjustment of a water turbine, wherein a fulcrum of a support base supporting the actuator housing is arranged in a thrust bearing portion.

Images