JP7089739B2 - Controller - Google Patents

Description

The present invention relates to a controller capable of controlling the flow rate of the fluid, and more particularly to a controller suitable when using a high pressure fluid.

As a controller suitable for using a high-pressure fluid, Patent Document 1 discloses a controller including a valve provided with a needle valve portion and a controller including an electropneumatic actuator controlled by air pressure as a control unit for driving the needle valve portion. ing.

Patent Document 2 discloses a controller including a needle portion and using a motor as a drive mechanism.

International Publication WO 2015/029866 Japanese Unexamined Patent Publication No. 2017-227265

The controllers described in Patent Document 1 and Patent Document 2 use a needle-type valve portion for the valve portion. A valve having a needle-type valve has an advantage that the flow rate of the fluid can be finely controlled because the stroke, which is the moving distance of the valve, is long.

However, since the stroke is long, the size of the controller is inevitably large, and it is not possible to meet the demand for a small controller.

The drive mechanism of the controller described in Patent Document 1 is an electropneumatic actuator. The electropneumatic actuator has an advantage that a large thrust can be obtained.

However, in the electropneumatic actuator, the thrust of the electropneumatic actuator fluctuates due to the pressure of the fluid flowing in the controller, and the opening degree of the valve fluctuates. It has the disadvantage that the degree cannot be kept constant.

The drive mechanism of the controller described in Patent Document 2 is a stepping motor. Since the stepping motor is controlled by the number of pulses, it has an advantage that the opening degree of the valve can be kept constant.

However, the stepping motor cannot withstand the pressure of the high-pressure fluid because the resistance to the thrust force applied to the motor shaft is small.

In order to obtain a small controller that controls high-pressure fluid, it is considered that a diaphragm valve is preferable as a valve body and a stepping motor is used as a drive mechanism. However, since the diaphragm valve has a small stroke, fine control is performed. Is not always preferable.

It is preferable to use a stepping motor as a drive mechanism because the valve opening is not affected by the pressure of the fluid flowing through the controller, but the motor shaft of the stepping motor cannot withstand the high pressure of the fluid. Therefore, the stepping motor cannot be used as it is.

An object of the present invention is to provide a small controller capable of accurately controlling the flow rate of a high pressure fluid.

The present invention (1) changes the positions of a valve box provided with a fluid passage and a diaphragm that opens and closes the fluid passage by contacting or separating from an annular valve seat provided in the valve box. A valve rod that deforms the diaphragm in the opening or closing direction and a driving device that moves the position of the valve rod are provided, and the operating shaft is located between the operating shaft of the driving device and the valve rod. A power transmission device that amplifies such a force and transmits it to the valve rod to open and close the diaphragm is provided, and the drive device is characterized in that the position of the operating shaft is adjusted by a stepping motor. It is a controller.

In the present invention (1), since a power transmission device is provided between the operating shaft of the drive device and the valve rod, the force applied to the operating shaft is amplified and transmitted to the valve rod, so that the valve portion has a stroke. Even with a small diaphragm, the stroke of the operating shaft can be amplified by the power transmission device, so the flow rate of the fluid flowing inside the controller can be controlled accurately.

Further, although the present invention (1) uses a stepping motor as a drive mechanism, a power transmission device that amplifies the force applied to the operating shaft and transmits the force to the valve rod is provided, so that the motor shaft of the stepping motor is provided. The force applied to the power transmission device can be reduced in inverse proportion to the amplification factor of the power transmission device. This action of the power transmission device allows the stepper motor to be used as the drive mechanism of the controller that controls the flow rate of the high pressure fluid.

The power transmission device is, for example, a pair arranged between the casing, the conical first roller receiving member provided on the operating shaft, the second roller receiving member provided on the valve rod, and both roller receiving members. Roller support, a pair of rolling rollers that come into contact with the tapered surface provided on the first roller receiving member, and a pair of pressing rollers that come into contact with the roller receiving surface of the second roller receiving member, and support each roller. The body is supported by the casing so that it can swing around the axis closer to the axis side of the first roller receiving member with respect to the axis of the presser roller (an example of an amplification type power transmission device). Will be done. By adopting the amplification type, the thrust can be reduced and the controller can be miniaturized.

This controller can be used for various purposes, but is particularly suitable for use when a high pressure fluid is used as the fluid and minute stroke control is required.

By using an amplified power transmission device, not only is it possible to move the valve stem against high voltage, but also the resolution can be increased even with a small stroke, so it is possible to control the minute amount of movement of the valve stem. Will be. By combining this power transmission device with a drive device that adjusts the position of the operating shaft based on the flow rate of the fluid flowing through the fluid passage by the stepping motor, it is possible to control the flow rate of the high-pressure fluid with high accuracy. As a result, a highly accurate controller (flow rate adjusting valve for high-pressure fluid), which has not been realized in the past, can be obtained.

In the present invention (2), the fluid passage has a central passage having an opening surrounded by the valve seat and facing the central portion of the diaphragm, and the diaphragm having an opening on the radial outer side of the valve seat. The present invention is characterized in that it has an outer passage facing the vicinity of the outer peripheral edge portion of the above, the outer passage is a inlet passage for the fluid, and the central passage is an outlet passage for the fluid. The controller according to (1).

Conventionally, the central passage is used for the entrance passage and the outer passage is used for the exit passage, whereas the outer passage is used for the entrance passage and the central passage is used for the exit passage. However, it prevents the fluid passage from opening suddenly.

The present invention (3) is the controller according to the present invention (2), wherein the diameter of the central passage is equal to or less than the diameter of the outer passage.

Conventionally, the central passage and the outer passage have a large diameter in order to increase the flow rate, and the diameter of the central passage and the diameter of the outer passage are almost the same. On the other hand, by reducing the diameter of the central passage, which is the exit passage, the Cv value can be set to, for example, 0.035, and thus the Cv value, which has not been realized in the past, is 0.0005 to 0. A controller with 035 and a diaphragm stroke of 0.002 to 0.2 mm can be obtained.

According to the controller of the present invention, it is a small controller that can withstand high voltage by using an amplification type power transmission device, and a controller by using a drive device using a stepping motor. It is possible to obtain a controller that can keep the valve opening constant without being affected by fluctuations in the pressure of the flowing high-pressure fluid.

A partial vertical cross-sectional view showing one embodiment of the controller according to the present invention shows a state in which the fluid passage is open. It is a figure which shows the state which the valve rod is moved from FIG. 1 and the fluid passage is closed. The relationship between the supply pressure, valve thrust and valve stroke when an electropneumatic actuator is used as a conventional drive mechanism is shown. The relationship between the stepping motor extrusion amount, the valve thrust, and the valve stroke when a stepping motor is used as the drive mechanism is shown.

In the following description, top and bottom and left and right refer to the top and bottom and left and right of the figure. The top, bottom, left, and right are for convenience, and when installing the controller, the top and bottom may be upside down or the top and bottom may be horizontal. Similarly, the left and right may be reversed.

1 and 2 show the controller of the present invention, wherein the controller 1 is a power transmission device 4 provided between a valve body 2, a drive device 3, and a valve body 2 and a drive device 3. And have.

The valve body 2 includes a valve box 11 in which the first and second fluid passages 12 and 13 are formed, a diaphragm 14 that opens and closes communication between the fluid passages 12 and 13, and a valve that deforms the diaphragm 14 in the opening or closing direction. It has a rod 15 and a bonnet 16 attached to the valve box 11 by a nut 17.

The valve box 11 is preferably made of SUS316L and has a recess 11a that opens upward. The first fluid passage 12 is connected to the large-diameter passage 12a opening to the right and the left end of the large-diameter passage 12a, and has a smaller diameter than the large-diameter passage 12a and is open to the center of the bottom surface of the recess 11a. It consists of a passage 12b. The second fluid passage 13 is connected to the large-diameter passage 13a that opens to the left and the right end of the large-diameter passage 13a, and has a smaller diameter than the large-diameter passage 13a and is open to the left side of the bottom surface of the recess 11a. It consists of a passage 13b.

The fluid flows in from the large-diameter passage 13a of the second fluid passage 13 and is discharged from the large-diameter passage 12a of the first fluid passage 12.

The valve box 11 is provided with an annular valve seat 18 so as to surround the opening of the central passage 12b of the first fluid passage 12. Since the valve seat 18 projects upward, an annular passage 11b communicating with the outer passage 13b of the second fluid passage 13 is formed on the outer periphery of the valve seat 18 in the valve box 11.

The diaphragm 14 is preferably made of metal and has a spherical shell shape, and the upward convex arc shape is in a natural state. The diaphragm 14 is fixed to the valve box 11 by being supported by the protruding outer peripheral edge portion of the bottom surface of the recess 11a of the valve box 11 and being pressed by the pressing adapter 19 from above. The central portion of the diaphragm 14 is pressed downward by the disc 20 fixed to the lower end portion of the valve stem 15, and is held at an open position having a predetermined opening by adjusting the vertical position of the disc 20. To. In this embodiment, the controller 1 is always open, and when the drive device 3 is operated, the central portion of the diaphragm 14 is strongly pressed against the valve seat 18 to obtain a closed state. There is.

The diaphragm 14 is made of, for example, a nickel alloy thin plate, cut out in a circular shape, and formed in a spherical shell shape with a central portion bulging upward. The diaphragm 14 may be made of a stainless steel thin plate or a laminate of a stainless steel thin plate and a nickel-cobalt alloy thin plate.

The valve box 11 may be heated by a heater in order to prevent freezing.

The drive device 3 uses a stepping motor 31. A motor shaft 32 projects from the lower end of the stepping motor 31, and the motor shaft 32 is connected to the connecting portion 33. The connecting portion 32 converts the rotational motion of the motor shaft 32 into a linear motion, and the rod 26 connected below the connecting portion 33 moves downward or upward with the rotation of the motor shaft 32. Since the lower end surface of the rod 26 is in contact with the upper end surface of the operating shaft 43, when the rod 26 moves downward, the operating shaft 43 is pressed downward.

The power transmission device 4 has an amplification mechanism 42 housed in a casing 41, and the amplification mechanism 42 is integrally provided at the lower end portion of the working shaft 43 and the working shaft 43 which is moved up and down by the driving device 3. Arranged between the conical first roller receiving member 44, the second roller receiving member 45 supported on the upper surface of the valve rod 15 and moving up and down integrally with the valve rod 15, and both roller receiving members 44, 45. A pair of roller supports 46, a pair of rolling rollers 47 that are rotatably supported by each roller support 46 and abut on the tapered surface 44a provided on the first roller receiving member 44, and each roller support. It is provided with a pair of pressing rollers 48 that are rotatably supported by the body 46 and come into contact with the horizontal roller receiving surface 45a of the second roller receiving member 45.

Each roller support 46 can swing about an eccentric shaft 49 supported by the casing 41 so as to have an axis in which the axis of the first roller receiving member 44 is closer to the axis of the presser roller 48. It has been done.

In this power transmission device 4, assuming that the force applied to the operating shaft 43 is F and the half angle of the tapered surface 44a of the first roller receiving member 44 is α, the rolling roller 47 has a force in the direction perpendicular to the tapered surface 44a. This force G that works and acts on one of the front and rear rolling rollers 47 is G = F ÷ 2Sinα.

The force G acting on the rolling roller 47 is transmitted to the second roller receiving member 45 via the roller support 46 and the pressing roller 48.

The distance between the axis of the eccentric shaft 49 and the axis of the rolling roller 47 is C, and the angle between the line connecting the axis of the rolling roller shaft 47 and the axis of the eccentric shaft 49 and the tapered surface 44a of the first roller receiving member 44 is set. γ, where the horizontal distance between the axis of the presser roller 48 and the axis of the eccentric axis 49 is δ, and the downward force of either the left or right presser roller 48 pushing the second roller receiving member 45 is N, N × δ = G. × Cosγ × C holds. Therefore, the downward force that both the left and right presser rollers 48 push the second roller receiving member 45, that is, the downward force that pushes the valve rod 15, is 2N = F × Cosγ × C ÷ Sin α ÷ δ, and α, γ, By setting δ and C to appropriate values, the force applied to the operating shaft 43 can be amplified and transmitted to the valve rod 15 by an arbitrary amplification factor (Cosγ × C ÷ Sin α ÷ δ).

For example, if α = 40 °, γ = 25 °, C = 12.5, and δ = 1.5, the amplification factor becomes about 12 times, and the diaphragm 14 can be pressed with a large force of about 12 times, for example. When the pressure is about 20 MPa, a force of 3000 N is required, but the flow rate can be controlled by a force of 1/12 of this. Therefore, even if the fluid has a high pressure, the diaphragm 14 is lifted by the fluid, and the fluid is prevented from flowing in and out in excess of the set value.

In the above, of FIGS. 1 and 2, FIG. 1 shows an open state. The amplification mechanism 41 is sandwiched between the front retainer plate 50 and the rear retainer plate 51 in the front-rear direction. Since the front retainer plate 50 is notched and illustrated in the drawing, the amplification mechanism 42 on the left side is shown so as to be visible. The amount of downward protrusion of the rod 26 from the lower surface of the connecting portion 33 is relatively small, and the operating shaft 43 is in the upper position accordingly, so that the upper ends of the roller supports 46 are close to each other. The roller receiving member 45 is located above. FIG. 2 shows a closed state, in which the amount of downward protrusion of the rod 26 from the lower surface of the connecting portion 33 is relatively large, and the operating shaft 43 is in the downward position accordingly, so that the roller support 46 The upper ends are separated from each other, and the second roller receiving member 45 is located below. From the comparison of FIGS. 1 and 2, it can be seen that the movement of the strokes of the valve stem 15 and the disc 20 can be made small with respect to the large stroke of the operating shaft 43.

Here, in the conventional controller, the first fluid passage 12 is an inlet passage and the second fluid passage 13 is an outlet passage, whereas in the controller 1, the second fluid passage 13 is an inlet passage. , The first fluid passage 12 is used as an outlet passage. As a result, in the conventional controller, when a high pressure is applied to the central portion (small area portion) of the diaphragm 14 facing the opening of the central passage 12b of the first fluid passage 12, and the control is opened. A high-pressure fluid suddenly flows into the outer peripheral portion (large area portion) of the diaphragm 14 in which the opening of the outer passage 13b of the second fluid passage 13 faces through the annular passage 11b, and the fluid passage is suddenly opened. In contrast to the controller 1, which cannot be adjusted to a predetermined flow rate, the controller 1 constantly receives pressure at the outer peripheral portion (large area portion) of the diaphragm 14 to adjust the flow rate, so that even a high-pressure fluid can be adjusted. It is prevented that the fluid passage is suddenly opened and the fluid flows in at once and cannot be adjusted to a predetermined flow rate.

When the fluid has a high pressure, the flow rate changes greatly with a slight vertical movement of the valve stem 15 and the disk 20, but in the controller 1, the amplification mechanism 42 provided in the power transmission device 4 changes the flow rate depending on the amplification factor. In addition to moving the valve stem 15 against the high pressure with a large set force to press the diaphragm 14 downward, the vertical movement amount of the valve stem 15 and the disk 20 is the vertical movement amount of the rod 26 of the drive device. Since it is reduced to 1 / amplification factor of, highly accurate control is possible.

FIG. 3 is a graph showing the relationship between the supply pressure of the gas supplied to the electropneumatic regulator, the valve thrust, and the valve stroke when the electropneumatic regulator is used as the conventional drive device. On the other hand, FIG. 4 is a graph showing the relationship between the push-out amount by the stepping motor, the valve thrust, and the valve stroke when the stepping motor 31 is used as the drive device of the present invention.

Looking at FIG. 3, when the supply pressure is gradually increased from 0.4 MPa, the valve thrust gradually increases and becomes constant after the supply pressure of 0.48 MPa. Since the valve thrust is not constant, the valve stroke is not linear either. As described above, according to the electropneumatic regulator used in the conventional high-pressure fluid controller, the valve stroke that affects the supply pressure and the opening degree cannot be linearly controlled, so that precise control cannot be performed.

Looking at FIG. 4, even if the pushing amount of the stepping motor is sequentially increased from 1 mm to 3 mm, the valve thrust is constant at 3000 N. Since the valve thrust is constant, the valve stroke changes linearly. As described above, in the present invention in which the stepping motor is used as the drive device, the valve stroke that affects the pushing amount and the opening degree of the stepping motor can be linearly controlled, so that the flow rate can be precisely controlled.

In this way, by using the amplification type power transmission device 4 and the drive device 3 which is a stepping motor, it is possible to obtain a small controller capable of controlling the flow rate of the high-pressure fluid with high accuracy. can.

1: Controller 2: Valve body 3: Drive device 4: Power transmission device 11: Valve box 11a: Recess 11b: Circular passage 12: First fluid passage 12a: Large diameter passage 12b: Central passage 13: Second fluid passage 13a: Large diameter passage 13b: Outer passage 14: Diaphragm 15: Valve rod 16: Bonnet 17: Nut 18: Valve seat 19: Presser adapter 20: Disc 26: Rod 31: Stepping motor 32: Motor shaft 33: Connecting portion 41: Casing 42: Amplification mechanism 43: Acting shaft 44: First roller receiving member 44a: Tapered surface 45: Second roller receiving member 45a: Roller receiving surface 46: Roller support 47: Rolling roller 48: Presser roller 49: Eccentric shaft 50: Front retainer plate 51: Rear retainer plate

Claims (3)

A valve box provided with a fluid passage, a diaphragm that opens and closes the fluid passage by contacting or separating from an annular valve seat provided in the valve box, and a diaphragm that opens or closes by changing the position. It is equipped with a valve rod that deforms in the direction and a drive device that moves the position of the valve rod.
A power transmission device is provided between the operating shaft of the driving device and the valve rod, which amplifies the force applied to the operating shaft and transmits the force to the valve rod to open and close the diaphragm. The position of the operating shaft is adjusted by a stepping motor.
The power transmission device includes a conical first roller receiving member provided at the lower end of the operating shaft, and a second roller receiving member that is supported on the upper surface of the valve rod and moves up and down integrally with the valve rod. , A pair of roller supports arranged between both roller receiving members, and a pair of rolling rollers that are rotatably supported by each roller support and come into contact with the tapered surface provided on the first roller receiving member. A controller comprising a pair of presser rollers that are rotatably supported by each roller support and abut on the horizontal roller receiving surface of the second roller receiving member . The fluid passage has an opening surrounded by the valve seat and faces the central portion of the diaphragm, and the fluid passage has an opening radially outside the valve seat and faces the vicinity of the outer peripheral edge portion of the diaphragm. The controller according to claim 1, further comprising an outer passage, wherein the outer passage is an inlet passage for the fluid and the central passage is an outlet passage for the fluid. The controller according to claim 2, wherein the diameter of the central passage is equal to or less than the diameter of the outer passage.

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