JP2019190620A - Controller - Google Patents

Abstract

To provide a small-sized controller capable of controlling a flow rate of high-pressure fluid with accuracy.SOLUTION: A controller comprises: a valve box 11 provided with a fluid passage; a diaphragm 14 that opens and closes the fluid passage by being brought into contact with or separating from an annular valve seat 18 provided in the valve box 11; a valve rod 15 that deforms the diaphragm 14 in an opening direction or a closing direction by changing a position; and a driving device 3 that moves a position of the valve rod 15. Between an operating shaft 43 of the driving device 3 and the valve rod 15, a power transmission device 4 is provided that amplifies force applied to the operating shaft 43 and transmits it to the valve rod 15. The diaphragm 14 is made of metal and can be deformed into a state in which the fluid passage is completely closed, a state in which the fluid passage is completely opened, and a state in which the fluid passage is partially opened. The driving device 3 adjusts a position of the operating shaft 43 by a stepping motor 31.SELECTED DRAWING: Figure 1

Description

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

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

  Patent Document 2 discloses a controller that includes a needle portion and uses a motor as a drive mechanism.

International Publication No. WO2015 / 029866 JP 2017-227265 A

  The controllers described in Patent Literature 1 and Patent Literature 2 use a needle-type valve portion for the valve portion. A valve having a needle-type valve portion 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 portion, is long.

  However, since the stroke is long, the size of the controller inevitably increases, and the demand for a small controller cannot be met.

  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 is fluctuated due to the pressure of the fluid flowing in the controller, and the opening 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 the advantage that the opening of the valve can be kept constant.

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

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

  Using a stepping motor as a drive mechanism is preferable because the opening of the valve 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 that can accurately control the flow rate of a high-pressure fluid.

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

  In the present invention (1), since the power transmission device for amplifying the force applied to the operating shaft and transmitting it to the valve stem is provided between the operating shaft of the drive device and the valve stem, 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 that the flow rate of the fluid flowing inside the controller can be accurately controlled.

  In the present invention (1), a stepping motor is used as a drive mechanism. However, since a power transmission device that amplifies the force applied to the operating shaft and transmits it to the valve stem is provided, the motor shaft of the stepping motor is provided. Can be reduced in inverse proportion to the amplification factor of the power transmission device. By this action of the power transmission device, a stepping motor can be used as a drive mechanism of a controller that controls the flow rate of the high-pressure fluid.

  The power transmission device includes, for example, a casing, a conical first roller receiving member provided on an operating shaft, a second roller receiving member provided on a valve stem, and a pair of rollers disposed between both roller receiving members. Each of the roller supports, a pair of rolling rollers in contact with the tapered surface provided on the first roller receiving member, and a pair of presser rollers in contact with the roller receiving surface of the second roller receiving member. A body supported by a casing so as to be able to oscillate around an axis closer to the axis of the first roller receiving member with respect to the axis of the presser roller (an example of an amplification type power transmission device); Is done. By using the amplification type, the thrust can be reduced and the controller can be miniaturized.

  Although this controller can be used for various applications, it is particularly suitable for use when a high-pressure fluid is used as the fluid and it is necessary to control a minute stroke.

  By using an amplifying type power transmission device, not only can the valve stem be moved against high pressures, but also the resolution can be increased with a small stroke, so the minute movement of the valve stem can be controlled. It becomes. By combining this power transmission device and a driving 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, an accurate controller (high-pressure fluid flow regulating valve) that has not been realized in the past can be obtained.

  The present invention (2) is characterized in that the fluid passage has an opening surrounded by the valve seat and a central passage facing the central portion of the diaphragm, and an opening on the radially outer side of the valve seat. And an outer passage facing the vicinity of an outer peripheral edge of the fluid, wherein the outer passage serves as an inlet passage for the fluid, and the central passage serves as an outlet passage for the fluid. It is a controller as described in (1).

  Conventionally, the central passage is used for the inlet passage and the outer passage is used for the outlet passage, whereas the outer passage is used for the inlet passage and the central passage is used for the outlet passage. However, the fluid passage is prevented from opening abruptly.

  The present invention (3) is the controller according to the present invention (2), characterized in that the diameter of the central passage is equal to or smaller than the diameter of the outer passage.

  Conventionally, the central passage and the outer passage have large diameters 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 that is the exit passage, the Cv value can be set to 0.035, for example, and thus the Cv value that could not be realized in the past is 0.0005 to 0.00. 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 pressure by using an amplification type power transmission device, and by using a drive device that uses 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.

It is a partial longitudinal cross-sectional view which shows one Embodiment of the controller by this invention, and shows the state in which the fluid passage is open. It is a figure which shows the state which moved the valve rod from FIG. 1, and closed the fluid channel | path. The relationship between supply pressure, valve thrust, and valve stroke when an electropneumatic actuator is used as a conventional drive mechanism is shown. The relationship between a stepping motor pushing amount, a valve thrust, and a valve stroke when a stepping motor is used as a drive mechanism is shown.

  In the following description, the top and bottom and the left and right refer to the top and bottom and the left and right of the drawing. The top, bottom, left, and right are for convenience. When the controller is installed, the top and bottom may be reversed or the top and bottom may be horizontal. Similarly, the left and right may be reversed.

  1 and 2 show a controller of the present invention. The controller 1 includes a valve body 2, a driving device 3, and a power transmission device 4 provided between the valve body 2 and the driving device 3. And.

  The valve body 2 includes a valve box 11 in which 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 an 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 that opens to the right and the left end of the large-diameter passage 12a, and the center that is smaller in diameter than the large-diameter passage 12a and that opens 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 an outer diameter that is smaller than the large-diameter passage 13a and that opens 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 13 a of the second fluid passage 13 and flows out from the large diameter passage 12 a 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 12 b of the first fluid passage 12. Since the valve seat 18 protrudes upward, an annular passage 11 b communicating with the outer passage 13 b 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 an upwardly convex arc shape is in a natural state. The diaphragm 14 is fixed to the valve box 11 by supporting the peripheral edge of the diaphragm 14 by a protruding outer peripheral edge of the bottom surface of the recess 11 a of the valve box 11 and pressing the diaphragm 14 from above. The central portion of the diaphragm 14 is pressed downward by a disk 20 fixed to the lower end of the valve stem 15, and is held at an open position with a predetermined opening by adjusting the vertical position of the disk 20. The In this embodiment, the controller 1 is normally open, and when the driving device 3 is operated, a closed state in which the central portion of the diaphragm 14 is strongly pressed against the valve seat 18 is obtained. Yes.

  The diaphragm 14 is made of, for example, a nickel alloy thin plate, and is formed in a spherical shell shape that is cut out in a circular shape and has a central portion bulged 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 driving device 3 uses a stepping motor 31. A motor shaft 32 protrudes from the lower end of the stepping motor 31, and the motor shaft 32 is connected to a 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 as the motor shaft 32 rotates. 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 includes an amplifying mechanism 42 housed in a casing 41, and the amplifying mechanism 42 is provided integrally with an operating shaft 43 that is moved up and down by the driving device 3 and a lower end portion of the operating shaft 43. The conical first roller receiving member 44, the second roller receiving member 45 supported on the upper surface of the valve stem 15 and moving up and down integrally with the valve stem 15, and the two roller receiving members 44, 45 are arranged. A pair of roller supports 46, a pair of rolling rollers 47 supported by the roller supports 46 so as to be able to roll and abutting a tapered surface 44 a provided on the first roller receiving member 44, and each roller support A pair of presser rollers 48 that are supported by the body 46 so as to be able to roll and abut against the horizontal roller receiving surface 45a of the second roller receiving member 45 are provided.

  Each roller support 46 can swing around an eccentric shaft 49 supported by the casing 41 so that the axis of the first roller receiving member 44 has an axis that is offset from the axis of the presser roller 48. Has been made.

  In this power transmission device 4, when 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 perpendicular to the tapered surface 44a. This force G acting on either 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 γ, where δ is the horizontal distance between the axis of the presser roller 48 and the axis of the eccentric shaft 49, and N is the downward force by which one of the left and right presser rollers 48 presses the second roller receiving member 45, N × δ = G × Cosγ × C holds. Therefore, the downward force that the right and left presser rollers 48 press the second roller receiving member 45, that is, the downward force that presses the valve stem 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 stem 15 with 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 is about 12 times, and the diaphragm 14 can be pressed with a large force of about 12 times. When the pressure is about 20 MPa, a force of 3000 N is required, but the flow rate can be controlled with a force of 1/12 of this. Therefore, even in the case of a high-pressure fluid, the diaphragm 14 is lifted by the fluid, and the fluid is prevented from flowing in and out beyond the set value.

  In FIG. 1 and FIG. 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. The front retainer plate 50 is shown cut away in the drawing so that the left amplification mechanism 42 can be seen. The downward protrusion amount of the rod 26 from the lower surface of the connecting portion 33 is relatively small, and accordingly, the operating shaft 43 is in the upper position, so that the upper end portions of the roller support 46 are close to each other, and the second The roller receiving member 45 is positioned above. FIG. 2 shows a closed state, in which the downward protrusion amount of the rod 26 from the lower surface of the connecting portion 33 is relatively large, and accordingly, the operating shaft 43 is in the lower position, so that the roller support 46 The upper end portions are separated from each other, and the second roller receiving member 45 is positioned below. From the comparison between FIG. 1 and FIG. 2, it can be seen that the movement of the stroke of the valve stem 15 and the disk 20 can be made minute 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 the outlet passage. Thereby, in the conventional controller, when a high pressure is applied to the central portion (small area portion) of the diaphragm 14 where the opening of the central passage 12b of the first fluid passage 12 is exposed, High-pressure fluid flows into the outer peripheral portion (large area portion) of the diaphragm 14 where the opening of the outer passage 13b of the second fluid passage 13 faces the annular passage 11b, and the fluid passage is suddenly opened. While the controller 1 cannot adjust the flow rate, the controller 1 constantly adjusts the flow rate by receiving the pressure at the outer peripheral portion (large area portion) of the diaphragm 14. The fluid passage is suddenly opened, and it is prevented that the fluid flows in at a stroke and cannot be adjusted to a predetermined flow rate.

  When the fluid is high pressure, the flow rate varies greatly with a slight amount of vertical movement of the valve stem 15 and the disk 20. However, in the controller 1, the amplification mechanism 42 provided in the power transmission device 4 causes the amplification rate to vary depending on the amplification factor. In addition to moving the valve rod 15 against the high pressure with a large force to press the diaphragm 14 downward, the vertical movement amount of the valve rod 15 and the disk 20 is the vertical movement amount of the rod 26 of the driving device. Therefore, 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 an electropneumatic regulator is used as a conventional driving device. On the other hand, FIG. 4 is a graph showing the relationship between the pushing amount by the stepping motor, the valve thrust, and the valve stroke when the stepping motor 31 is used as the driving device of the present invention.

  Referring to FIG. 3, when the supply pressure is sequentially increased from 0.4 MPa, the valve thrust gradually increases and becomes constant after the supply pressure 0.48 MPa. Since the valve thrust is not constant, the valve stroke is not linear. 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.

  As shown in FIG. 4, even when 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. Thus, in the present invention in which the stepping motor is used as the driving device, the valve stroke that affects the pushing amount and the opening degree of the stepping motor can be linearly controlled, so that precise flow rate control is possible.

  Thus, by using the amplification type power transmission device 4 and the drive device 3 that is a stepping motor, it is possible to obtain a small controller that can control the flow rate of high-pressure fluid with high accuracy. it can.

1: Controller 2: Valve body 3: Drive device 4: Power transmission device 11: Valve box 11a: Recess 11b: Annular 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: Amplifying mechanism 43: Operating 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: Pressing roller 49: Eccentric shaft 50: Front side retainer plate 51: Rear side 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 opening or closing the diaphragm by changing the position A valve stem that deforms in the direction, and a drive device that moves the position of the valve stem,
Between the operating shaft of the driving device and the valve stem, a power transmission device that amplifies the force applied to the operating shaft and transmits it to the valve rod to open and close the diaphragm is provided. A controller for adjusting the position of the operating shaft by a stepping motor.   The fluid passage includes an opening surrounded by the valve seat and a central passage facing the central portion of the diaphragm, and an opening on a radially outer side of the valve seat and facing an outer peripheral edge of the diaphragm. 2. The controller according to claim 1, 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 a diameter of the central passage is equal to or less than a diameter of the outer passage.

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