JPH0594219A - Pilot operation type motor-operated valve - Google Patents

Abstract

PURPOSE:To provide a motor-driven valve having new constitution which effectively copes with an increase in the diameter of the valve without increasing the size of a motor operation part specially. CONSTITUTION:A diaphragm chamber 8 which dives a main valve body 4 by a diaphragm 7 by utilizing the pressure of liquid itself to be controlled is communicated with the primary side 1 of a main valve 3 through a throttle valve 13 and a pair of a pilot valve main body 15 and a pilot valve seat 19 are arranged at a main valve shaft 9 and a pilot valve shaft 18 respectively; and the diaphragm chamber 8 of the main valve 3 is communicated with the secondary side 2 of the main valve 3 through the pilot valve seat 19. The pilot valve shaft 18 connected to a potentiometer 21 is not mechanically connected to the main valve body 4, the pilot valve shaft 18 is moved by a motor 23 in the forward and backward directions, and a spring 15 which is compressed to absorb deflection corresponding to the full stroke of the main valve body 4 is mounted on the main valve shaft.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrically operated valve for controlling the pressure and flow rate of fluid.

[0002]

2. Description of the Related Art Conventionally, an external force type control valve using air or electricity as a power source has been used when precisely controlling the pressure or flow rate of a fluid or when performing remote control. In these control valves, the pressure and flow rate of the controlled fluid are input to the controller, and if there is a deviation from the target value, the control signal for changing the opening of the control valve is a diaphragm actuator or electric operation. It is output to the machine, whereby the control valve is actuated and the flow rate of the controlled fluid is adjusted. By the way, in the case of a pneumatic control valve, an air source such as a compressor is required, and such an air source is not always available. Therefore, an electric control valve that uses electricity as a power source (hereinafter, simply referred to as a motorized valve). ) Is preferable and practical.

In the case of an electrically operated valve, the rotational force of the electric motor can be amplified through a speed reducer, and the gear mechanism can be used to adjust the valve to fully open or fully closed, or any opening in between. As described above, there is an advantage in that only electricity is required as a power source, and air pressure or hydraulic pressure, which requires auxiliary equipment such as a compressor and a pump, is unnecessary.

FIG. 6 shows the simplest structural example of a conventional motor-operated valve. In the figure, 31 is a primary side, 32 is a secondary side, 33 is a main valve, 34 is a main valve body, and 35 is a main valve. Valve seat, 36
Is a cover. The main valve body 34 is connected to the motor 37 via the valve shaft 34a. In such a motor-operated valve, the motor 37 requires a maximum driving force when the main valve body 34 is closed, that is, the force due to the pressure difference between the upper and lower sides of the main valve body 34 and the frictional force of each sliding portion of the valve. In order to prevent leakage, it is necessary to have sufficient resultant force with the surface pressure of the main valve body 34 against the main valve seat 35. Therefore, the larger the diameter of the valve, the larger the output of the motor 37 must be.

Next, FIG. 7 shows another structural example of the conventional motor-operated valve. In this motor-operated valve, the piston chamber is provided above the main valve body 34 in order to reduce the driving force of the motor 37, that is, the load. 38, and prevents the pressure of the piston chamber 38 from escaping to the secondary side by the seal member 39 mounted on the sliding surface of the outer periphery of the main valve body 34.
A communication hole 40 is formed in the main valve body 34 so that the primary side pressure can be introduced into the piston chamber 38 through the communication hole 40. It is designed to eliminate. In the case of the electrically operated valve of this structural example, the driving force required for the motor 37 may be the resultant force of the two forces of the frictional force of each sliding portion of the valve and the surface pressure on the main valve seat 35. Become. When the main valve element 34 is lifted to open the valve, it is performed against the weight of the movable part, so that the motor 37 inevitably has a large output.

FIG. 8 shows still another example of the structure of a conventional motor-operated valve, but this main valve structure is usually called a pilot balance type or parent-child valve type. In the figure, the main valve body 3
A pilot valve body 41 fixed to the tip of the valve shaft 34a is disposed inside the valve shaft 4, and a coil spring 43 is interposed between the pilot valve body 41 and the pilot valve seat 42. Further, the primary pressure is introduced into the piston chamber 38 through the fitting gap between the cylinder 44 and the main valve body 34 as a piston. According to the motor-operated valve shown in FIG. 8, when the valve shaft 34a is lifted, first, the pilot valve body 41 at the tip thereof is separated from the pilot valve seat 42. As a result, the pressure in the piston chamber 38 is released to the secondary side pressure via the communication hole 40 'formed in the upper portion of the main valve body 34, so that the pressure between the upper and lower sides of the main valve body 34 becomes the same. As a result, the driving force required for the motor 37 can be reduced. The pilot-balanced valve structure has the same function as the electrically operated valve having the structure shown in FIG. 7, and the main valve element 34 can be directly driven by the motor 37.

[0007]

However, in the conventional motor-operated valve, in particular as in the motor-operated valve shown in FIG. 7 or FIG. 8, a device for reducing the driving force required for the motor 37 has been made. In these cases, since the main valve body 34 is directly driven by the motor 37 as described above, there is a limit to reducing the driving force of the motor 37, and therefore a driving force of a predetermined magnitude is still required. Therefore, the electric operation part had to be large. That is, the main valve body 34 is pressed against the main valve seat 35 to secure a tight sealing of the valve hole in order to prevent a large operating force for opening and closing the valve against the pressure difference across the main valve body 34 and a leak at the time of valve closing. It required a large operating force.

In this type of electrically operated valve, the larger the diameter of the valve and the larger the pressure difference before and after the valve, the larger the area around the electrically operated portion composed of the electric motor and gears. Not only is the product itself becoming larger,
In addition to making the product cost expensive, it causes inconvenience such as increase in power consumption. In the case of a larger operating unit, it is against the inertial force of the power transmission system parts that rotate inside,
When the power transmission system is braked to the specified valve opening, the components such as gears and brakes are subjected to extremely rapid and large loads, and wear of each component, especially in operating conditions in which start and stop are frequently repeated. There is a problem such as becoming severe.

In view of the above situation, it is an object of the present invention to provide an electrically operated valve having a novel structure which can effectively cope with an increase in the diameter of the valve without increasing the size of the electrically operated portion.

[0010]

A pilot operated motor operated valve according to the present invention is a throttle valve that connects a diaphragm chamber for driving a main valve body with a diaphragm using the pressure of a fluid to be controlled and a primary side of the main valve. And a pair of pilot valve bodies and pilot valve seats are provided on the main valve shaft and the pilot valve shaft respectively, and the diaphragm chamber and the main valve of the main valve are connected via the pilot valve seats. Of the pilot valve shaft connected to the potentiometer is not mechanically connected to the main valve body, and the pilot valve shaft is movable forward and backward by a motor. A spring capable of compressing and absorbing the deflection corresponding to the full stroke of the main valve body is attached to the main valve shaft.

Further, in the pilot operated motor-operated valve according to the present invention, the piston chamber for driving the main valve body by the piston by utilizing the pressure of the fluid itself to be controlled and the primary side of the main valve communicate with each other through the throttle. , A pair of pilot valve seats and pilot valve bodies are provided on the main valve body and the pilot valve shaft, respectively, and the piston chamber of the main valve and the secondary side of the main valve communicate with each other via the pilot valve seats. However, the pilot valve shaft connected to the potentiometer is not mechanically connected to the main valve body, and the pilot valve shaft is movable forward and backward by a motor, A spring capable of compressing and absorbing the deflection corresponding to the full stroke is mounted on the pilot valve shaft.

[0012]

According to the present invention, when the pressure in the diaphragm chamber or the piston chamber rises, the main valve body closes, and when the pressure falls, the main valve body opens. Further, since the diaphragm chamber or the piston chamber communicates with the primary side via the throttle or the throttle valve having the fluid passage portion having a small cross-sectional area, the main valve body pushes the primary side pressure to the diaphragm chamber or the piston chamber. Is introduced, the valve is pushed down to close the valve. The controller, which receives an electric signal converted from the pressure or flow rate of the fluid to be controlled, compares it with a preset target value, and if there is an excess or deficiency, the potentiometer sets a predetermined value. An electric signal corresponding to the valve opening for correcting the pressure and the like to a target value is sent to the motor until the command value is reached, and the motor rotates forward or backward to move the pilot valve seat. Then, when the pilot valve seat moves in the direction away from the pilot valve body, the flow rate flowing out from the opening of the pilot valve seat to the secondary side becomes larger than the flow rate flowing in from the throttle or the throttle valve, The pressure in the diaphragm chamber or the piston chamber drops and the main valve body opens. On the other hand, when the pilot valve seat moves in the direction of approaching the pilot valve body,
Since the flow rate of the fluid in the diaphragm chamber or piston chamber flowing out from the opening of the pilot valve seat to the secondary side is smaller than the flow rate flowing in from the throttle valve or throttle valve, the pressure in the diaphragm chamber or piston chamber rises and the main valve The body closes.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the pilot operated motor operated valve according to the present invention will be described below with reference to FIGS. In the figure, 1 is the primary side, 2 is the secondary side, 3 is the main valve, 4 is the main valve body,
Reference numeral 5 is a main valve seat, 6 is a cover, 7 is a diaphragm which is stretched between the main valve 3 and the cover 6, and is fixed to the main valve body 4, and 8 is a diaphragm defined by the diaphragm 7. It is a room. The main valve shaft 9 integrated with the main valve body 4 is guided by the guides 10a and 10b in the vertical movement, but the main valve body 4 is normally moved downward by the compression coil spring 11. Being energized. Further, the diaphragm chamber 8 has a communication passage 12
Is connected to the primary side 1 via the throttle valve 13.

Further, in the figure, 14 is a cylindrical body which is inserted at the tip of the main valve shaft 9 so as to be movable by a constant stroke and which houses a compression coil spring 15, and 16 is the cylindrical body 1.
4 is a pilot valve element fixed to the tip of 4, a cylinder 17 is abutted against the cover 6, and 18 is a cylinder.
Is a pilot valve shaft which is supported by the cylinder 17 so as to move back and forth on the same line as the main valve shaft 9, and 19 is a pilot valve shaft 18.
A pilot valve seat 20 is provided at the tip of the pilot valve seat 20, and an opening 20 is formed in the pilot valve seat 19. The pilot valve shaft 18 has a potentiometer 21 attached to the end opposite to the pilot valve seat 19, and a spiral gear 22 and a motor 2 formed in the middle thereof.
3 is connected to the motor 23 through meshing of a worm 24 fixed to the output shaft. In addition, the cylinder 17
Communicates with the secondary side 2 through a communication passage 25.

The operation control system in the above case is shown in FIG.
As shown, potentiometer 21 and motor 23
Is connected to a controller, and a detection signal from a sensor for detecting the pressure or flow rate of fluid is input to the controller. Also,
In the controller, the valve opening signal is input from the potentiometer, the target value set by the target value setter is compared with the detection signal of the sensor, and the motor 23 is compared to the motor 23 based on the calculation processing result. A drive control signal is sent out.

The pilot operated motor-operated valve according to the present invention is constructed as described above, and its operation will be described below.
First, in the state shown in FIG. 1, since the pilot valve body 16 is in contact with the pilot valve seat 19, the outflow of fluid from the diaphragm chamber 8 to the secondary side 2 through the opening 20 is blocked. Further, due to the pressure of the fluid on the primary side 1 that has flowed into the diaphragm chamber 8 via the throttle valve 13, the main valve body 4
Is still pressed against the main valve seat 5, and the main valve 3 is closed.

When the controller of the operation control system sends a drive control signal to the motor 23 in the valve closed state, as shown in FIG. 3, the pilot valve seat 19 spirals.
When the motor 23 is moved upward through the engagement of the gear 22 and the motor 23, the pilot valve seat 19 separates from the pilot valve body 16, and the opening area due to the gap between them is larger than the opening area of the throttle valve 13. Become. When the amount of the fluid flowing out from the diaphragm chamber 8 becomes larger than the amount of the fluid flowing into the diaphragm chamber 8, the main valve body 4 moves upward and the main valve 3 opens.

This valve opening operation, that is, the upward movement of the main valve body 4, causes the amount of fluid that escapes through the gap formed between the pilot valve body 16 and the pilot valve seat 19 and flows from the throttle valve 13 into the diaphragm chamber 8. Continue until the amount of fluid to be equalized. In this case, since the cross-sectional area of the fluid passage portion of the throttle valve 13 is small, that is, the passing fluid is throttled in the fluid passage portion, the gap between the pilot valve body 16 and the pilot valve seat 19 is finally extremely small. (Although it depends on the size of the throttle of the throttle valve 13, usually 0.1 to 0.2 m
m is about). As a result, the moving distance (valve lift amount) of the upward movement of the main valve body 4 matches the moving distance of the pilot valve seat 19.

Contrary to the above case, as shown in FIG.
When the pilot valve seat 19 is moved downward by the motor 23, the pilot valve seat 19 is lowered to a predetermined position and the pilot valve body 16 is applied to the pilot valve seat 19.
Sit down. In this case, the pilot valve seat 19 is the motor 2
Since the pilot valve seat 19 descends irrespective of the position of the pilot valve body 16 in accordance with the driving by the drive valve 3, the pilot valve seat 19 keeps the pilot valve seat 16 seated on the pilot valve seat 19 and the compression coil spring 15 Is pressed and stopped at the predetermined position.

In this state, since the pilot valve body 16 is seated on the pilot valve seat 19 as described above, the opening 20 of the pilot valve seat 19 is closed, and therefore the fluid in the diaphragm chamber 8 is splashed. It cannot flow out through the opening 20 and exclusively the fluid on the primary side 1 flows into the diaphragm chamber 8 via the throttle valve 13. As a result, the main valve body 4 is pushed down by the diaphragm 7 and descends. However, the downward movement of the main valve body 4 causes the compression coil spring 15 in the cylindrical body 14 that has been elastically restored to its free length and the pilot valve seat. When the pilot valve body 16 seated on the valve seat 19 is slightly detached from the pilot valve seat 19, the amount of fluid escaping through the opening 20 of the pilot valve seat 19 and the amount of fluid flowing into the diaphragm chamber 8 from the throttle valve 13 are Continue until the quantity equals. As a result, the movement distance of the downward movement of the main valve body 4 matches the movement distance of the pilot valve seat 19.

As described above, in the pilot operated motor operated valve of the present invention, the pilot valve body 16 and the pilot valve seat 19 are provided.
When the gap is increased, the main valve body 4 moves upward, and when the gap is decreased, the main valve body 4 moves downward. That is, even if the vertical position of the pilot valve seat 19 changes due to the driving of the motor 23, the pilot valve body 16 automatically follows the moved pilot valve seat 19 and acts so as to make them extremely close to each other. Based on such a principle of operation, by driving the motor 23 to bring the pilot valve seat 19 to a desired position, the main valve body 4 can be positioned, that is, the main valve 3 can be set to a predetermined valve opening degree. it can.

Further, the main valve body 4 can be moved as a result by driving the motor 23, but in that case, the motor 23 and the main valve body 4 are not mechanically connected and the main valve body 4 is not mechanically connected. 4 is driven through the diaphragm 7 by utilizing the pressure of the fluid flowing into the diaphragm chamber 8.
That is, the driving force of the motor 23 depends on the weight of the main valve body 4 and the main valve body 4.
It is separated from the thrust due to the fluid pressure acting on, and is not affected by the weight or the like at all. In this way, the motor 23
Requires only that the lightweight pilot valve seat 19 be driven in the vertical direction through the meshing of the spiral gear 22 and the worm 24, the driving force required for the motor 23 is extremely small. The size can be effectively reduced. Here, if a power failure occurs during the operation of the valve, as long as the fluid is supplied to the primary side 1, it is set by the position of the pilot valve body 16 when the power failure occurs. The valve opening of the main valve 3 to be held can be maintained.

In the above embodiment, the pilot valve body 16
And the arrangement of the pilot valve seat 19, the pilot valve seat 19
If the outlet of the main valve 3 communicates with the secondary side 2 of the main valve 3, the main valve shaft 9
Alternatively, it may be provided on any of the pilot valve shafts 18.

FIG. 5 shows a second embodiment of the pilot operated motor operated valve according to the present invention. In this second embodiment, the main valve body 4 '
Has a piston structure. That is, the main valve body 4 ′ is slidably fitted into the cylinder 26 mounted on the cover 6, whereby the piston chamber 27 is formed. In addition, the main valve body 4
′ Is provided with a pilot valve seat 19 ′, the opening 20 of which
′ Communicates with the secondary side 2. As shown further,
The primary side 1 and the piston chamber 27 communicate with each other via a throttle 28 provided in the main valve body 4 '. On the other hand, the tip of the pilot valve shaft 18 is provided with a cylinder 14 having a compression coil spring 15 built therein and a pilot valve 16 fixed to the tip of the cylinder 14.

In the second embodiment, as described above, the inflow passage and the outflow passage for the piston chamber 27 are formed in the main valve body 4'as a piston through the throttle 28 and the opening 20 '. Also in (1), the motor 23 and the main valve body 4'are not mechanically connected, and the pressure of the fluid flowing into the piston chamber 27 is used to drive the main valve body 4 '. That is, the driving force of the motor 23 is the main valve body 4 '.
Is separated from the thrust force due to the fluid pressure acting on the main valve body 4'and is not affected by the weight or the like.

[0026]

As described above, according to the present invention, the motor and the main valve body are not mechanically connected to each other, and the force for driving the main valve body is the fluid that is applied downward to the diaphragm or the like of the main valve. Since the pressure is used, the driving force of the motor is separated from the weight of the main valve body and the thrust due to the pressure applied thereto. Therefore, since the driving force required for the motor only needs to drive the small pilot valve seat, the motor can be effectively downsized, and the conventional large motor is no longer required.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a first embodiment of a pilot operated motor operated valve according to the present invention.

FIG. 2 is a block diagram showing an operation control system in the first embodiment of the pilot operated motor-operated valve according to the present invention.

FIG. 3 is a vertical cross-sectional view for explaining the valve operation when the pilot valve seat moves upward in the first embodiment of the pilot operated motor-operated valve according to the present invention.

FIG. 4 is a vertical cross-sectional view for explaining the valve operation when the pilot valve seat moves downward in the first embodiment of the pilot operated motor-operated valve according to the present invention.

FIG. 5 is a vertical cross-sectional view of a second embodiment of the pilot operated motor operated valve according to the present invention.

FIG. 6 is a vertical cross-sectional view of a conventional electric valve.

FIG. 7 is a vertical cross-sectional view of another conventional motor-operated valve.

FIG. 8 is a vertical cross-sectional view of another conventional motor-operated valve.

[Explanation of symbols]

 1 Primary side 2 Secondary side 3 Main valve 4 Main valve body 4'Main valve body 5 Main valve seat 6 Cover 7 Diaphragm 8 Diaphragm chamber 9 Main valve shaft 11 Compression coil spring 12 Communication passage 13 Throttle valve 14 Cylindrical body 15 Compression coil Spring 16 Pilot valve body 17 Cylinder 18 Pilot valve shaft 19 Pilot valve seat 19 'Pilot valve seat 20 Opening 20' Opening 21 Potentiometer 23 Motor 25 Communication passage 26 Cylinder 27 Piston chamber 28 Throttle

Claims (2)

[Claims] 1. A main valve shaft and a pilot valve shaft, wherein a diaphragm chamber for driving a main valve body by a diaphragm utilizing the pressure of a fluid to be controlled communicates with a primary side of the main valve via a throttle valve. A pair of pilot valve bodies and pilot valve seats, respectively, and via the pilot valve seats, the diaphragm chamber of the main valve communicates with the secondary side of the main valve and is connected to a potentiometer. The pilot valve shaft is not mechanically connected to the main valve body, and the pilot valve shaft is movable by a motor so that it can move back and forth. A pilot-operated motor-operated valve, wherein a spring capable of compressing and absorbing is attached to the main valve shaft. 2. A piston chamber in which a main valve body is driven by a piston utilizing the pressure of the fluid to be controlled and a primary side of the main valve are communicated with each other through a throttle, and the main valve body and the pilot valve shaft are connected to each other. A pair of pilot valve seats and a pilot valve body are respectively arranged, and the pilot valve connected to the potentiometer by connecting the piston chamber of the main valve and the secondary side of the main valve via the pilot valve seats. The shaft is not mechanically connected to the main valve body, and the pilot valve shaft is movable by a motor so that it can move forward and backward, and the deflection corresponding to the full stroke of the main valve body is compressed and absorbed. A pilot operated motor operated valve, wherein a possible spring is mounted on the pilot valve shaft.