JP2916822B2 - Converter device for water turbine governor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a converter device for a water turbine governor, and more particularly to a converter device for a water turbine governor which converts an input of an electric signal into a mechanical displacement of a spool and outputs the mechanical displacement.

[0002]

2. Description of the Related Art In general, a converter device of a water turbine governor for converting an input of an electric signal into a mechanical displacement of a spool and outputting the converted signal is introduced in Japanese Patent Application Laid-Open No. Hei 2-104981, and the like. It is shown in FIG.

[0003] Spools 2a, 2b and 2c are connected to an output shaft 15 of the solenoid type converter 1 for receiving an electric signal, and these spools are disposed so as to be slidable in the axial direction in a sleeve 3 housed in a control valve cylinder 5. Have been. The sleeve 3 is provided with a plurality of openings that are controlled to be opened and closed by spools 2b and 2c. The control valve cylinder 5 at a position corresponding to the openings is connected to oil passages 6a to 6e. I have. The line 6a communicates with the oil collecting tank 10 via a filter 13, an unloader 12, and a pump 11, and the line 6b is connected to a line 6e in the control cylinder 5,
“e” communicates with the oil collecting tank 10. Further, the line 6c is communicated with a lower chamber 8b on one pressure receiving surface side of a piston 9 moving in the drive valve cylinder 8, and the line 6d is communicated with an upper chamber 8a on the other pressure receiving surface side of the piston 9. . A stepping motor 17 is connected to an upper end of the output shaft 15 of the solenoid converter 1 via a joint mechanism 16 having a degree of freedom in rotational and axial movements.

When an electric signal is input to the solenoid converter 1 to output a downward driving force to the spools 2a, 2b and 2c, the pipeline 2a is controlled by the spool 2c.
Communicates with the line 6d, and the pressure oil from the pressure oil device 7 is supplied to the upper chamber 8a of the drive cylinder 8 through these lines 6a and 6d, and at the same time, the line 6c is connected to the line by the spool 2b. The lower chamber 8b of the drive cylinder 8 communicates with the oil collecting tank 10 through the passage 6b and the conduit 6e. Therefore, the piston 9 is driven downward. On the other hand, when an electric signal is input to the solenoid type converter 1 and an upward driving force is output to the spools 2a, 2b and 2c, the connections of the respective pipes are switched and the upper chamber 8a of the drive cylinder 8 is connected to the pipes. 6d, 6e
And the lower chamber 8b receives the supply of the pressure oil from the pressure oil device 7 through the pipe 6c and the pipe 6a, and the piston 9 is driven upward. The equipment connected to 9 is controlled.

In this type of hydraulic apparatus, the spool 2a, 2b, 2c is eccentric with time and is pressed against the inner wall of the sleeve 3, and finally a hydraulic clock phenomenon occurs in which the spool 2a, 2b, 2c is constrained by metal contact. To prevent this, a high-frequency voltage is always applied to the solenoid converter 1 to apply a slight axial vibration to the spools 2a, 2b, 2c, and the stepping motor 17 is constantly operated to rotate the spools 2a, 2b, 2c. Let me.

[0006]

As described above, in the converter device of the conventional water turbine governor, a high frequency voltage is always supplied to the solenoid type converter 1 in order to prevent a hydraulic clock phenomenon occurring between the spool and the sleeve. , And a stepping motor 17 is newly provided, which complicates the overall configuration.

An object of the present invention is to provide a converter device for a water turbine governor which can prevent a hydro-clock phenomenon with a simple structure.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention uses a control device in which hysteresis is added to a closed-loop feedback signal for controlling a converter by comparing an electric signal to the converter with a position of a spool. It is characterized by having been.

[0009]

Since the converter device of the water turbine governor according to the present invention has the above-described configuration, control overshoot occurs due to the feedback signal to which the hysteresis is added, and the converter operates in the reverse direction to correct the overshoot. The micro-vibration which is caused to operate is induced, and the spool which is displaced by the converter does not require a special device such as a stepping motor for applying the micro-vibration as in the prior art. Thus, the hydraulic clock phenomenon can be prevented.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a system diagram showing a converter device of a water turbine governor according to an embodiment of the present invention. A rotary converter 1 constituted by a stepping motor or a DC motor outputs an electric signal to an electric signal input. The shaft 15 is rotated.
The output shaft 15 is connected to a screw mechanism 18 via a joint mechanism 16 having a degree of freedom with respect to rotation and axial movement. A nut 18b of the screw mechanism 18 is connected to the output shaft 15, and The rod portion 18a is connected to the spools 2a, 2b, 2c via a joint mechanism 19 having a degree of freedom with respect to the axial movement. These spools are slidably arranged in the sleeve 3 fitted in the control valve cylinder 5. Openings controlled by the respective spools 2a, 2b, 2c are formed in the sleeve 3, and one end of each of pipes 6a to 6e serving as an oil passage is provided in the control valve cylinder 5 corresponding to each of the openings. Each is connected. The other end of the line 6a communicates with the oil collecting tank 10 via a filter 13, an unloader 12, and a pump 11, and the line 6c
Is connected to the lower chamber 8b of the drive valve cylinder 8 and to the line 6
The other end of d is connected to the upper chamber 8a of the drive cylinder 8. Further, the other end of the line 6b is connected to the line 6b in the control valve cylinder 5.
e, and the line 6 e is connected to the oil collecting tank 10.

Now, when an electric signal is given to the rotary converter 1, its rotary shaft 15 rotates by a rotation angle corresponding to the electric signal, and its rotational torque is transmitted to the screw mechanism 18. The rotation of the spool 18a is converted into the axial movement of the rod 18a and the spools 2a, 2b, 2
c. When the spools 2a, 2b, 2c are displaced, the upper chamber 8a and the lower chamber 8b alternately disconnect the connection between the pipeline 6a receiving the supply of the pressure oil from the pressure oil device 7 and the oil collecting tank 10. As a result, the piston 9 can be driven upward or downward to control the equipment connected thereto in the same way as a conventional converter device. At this time, the rotary converter 1 is controlled by the control device 14. A block diagram of the control device 14 is shown in FIG.

The electrical signal 24 applied to the rotary converter 1 is compared with the position of the spools 2a, 2b, 2c shown in FIG. 1 is input. The rotary converter 1 rotates by a rotation angle corresponding to the electric signal 24, and the rotation torque is transmitted to the screw mechanism 18. At this time, the rotation torque changes the lead of the screw in the screw mechanism 18 to l. In this case, the thrust is converted to 2π / l times the axial thrust, so that the spools 2a, 2b, 2c can be operated with a large force without increasing the size of the rotary converter 1. In such a closed loop, in the present embodiment, the hysteresis 23 is added to the feedback signal 22,
The new feedback signal to which the hysteresis 23 is added and the electric signal 24 are compared. Here, since the control time constant of the rotary converter 1 is much faster than the change period of the electric signal 24, the newly added hysteresis 23 causes excessive control, and as a result, the output shaft 15 and the spools 2a, 2b , 2c. Since the micro-vibration is generated in relation to the control time constant of the rotary converter 1, it becomes high-frequency micro-vibration. In this way, the micro vibration is always applied to the spools 2a, 2b, 2c,
The above-described hydraulic clock phenomenon is caused by the motor 17 shown in FIG.
Can be prevented without adding a special device such as

FIG. 3 is a system diagram showing a converter device of a water turbine governor according to another embodiment of the present invention. A rotary converter 1 constituted by a stepping motor or a DC motor rotates an output shaft 15 in response to an input of an electric signal. The output shaft 15 is connected to a spline mechanism, for example, a ball spline mechanism 20, via a joint mechanism 16 having a degree of freedom in rotational and axial movements. The ball spline mechanism 20 includes a rod portion 20a, a nut portion 20b, and a ball 20c. The output shaft 15 is connected to the rod portion 20a. The nut portion 20b is connected to the spools 2a, 2b, 2c via a rod portion 18a screwed to the nut portion 18b of the screw mechanism 18. Other configurations are the same as those in FIG. 1, and the same components are denoted by the same reference numerals and description thereof is omitted.

In this configuration, since the ball spline mechanism 20 is provided between the rotary converter 1 and the screw mechanism 18, the rotation of the output shaft 15 of the rotary converter 1 involves rotation of the spools 2a, 2b, 2c. Converted to directional motion.

Therefore, when the rotary converter 1 is controlled by the control device 14 described with reference to FIG. 2, the spools 2a, 2b, 2c are subjected to micro-vibration which constantly rotates, thereby further increasing the vibration. The hydraulic clock phenomenon can be effectively prevented.

In each of the above-described embodiments, the rotational torque is converted into a large axial thrust and the spools 2a, 2b, 2
Rotary converter 1 capable of coping with an increase in the size of c
However, the same effect can be obtained by using the control device 14 in which the hysteresis is added to the feedback signal even in a solenoid type converter.

[0018]

As described above, according to the present invention, the hysteresis is added to the feedback signal of the closed loop for controlling the converter by comparing the electric signal to the converter with the position of the spool. With a simple configuration without providing a special dedicated device such as a stepping motor for giving a minute vibration, a slight vibration can be given to the spool to prevent the hydraulic clock phenomenon.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a converter device of a water turbine governor according to one embodiment of the present invention.

FIG. 2 is a block diagram of a control device which is a main part of FIG.

FIG. 3 is a system diagram showing a converter device of a water turbine governor according to another embodiment of the present invention.

FIG. 4 is a system diagram showing a conventional converter device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rotary converter 2a Spool 2b Spool 2c Spool 3 Sleeve 5 Control valve cylinder 7 Pressure oil device 18 Screw mechanism 20 Ball spline mechanism 22 Feedback signal 23 Hysteresis 24 Electric signal

Claims (2)

(57) [Claims] 1. A water turbine governor having a control device for controlling displacement of a spool connected to an output shaft thereof in accordance with an electric signal input to a converter, and controlling an oil passage based on displacement of the spool. The converter device according to claim 1, wherein the control device compares the position of the spool with the electric signal to the converter and controls the converter to provide a closed-loop feedback signal, wherein hysteresis is added to the water turbine governor. Converter device. 2. The apparatus according to claim 1, wherein an output shaft of the converter and the spool are connected via a screw mechanism, and a spline mechanism is provided between the screw mechanism and the output shaft. Water turbine governor converter device.