JP4113425B2 - Piezoelectric element driven metal diaphragm type control valve - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a piezoelectric element-driven metal diaphragm type control valve applied to a pressure type flow rate control apparatus such as a semiconductor manufacturing facility or a chemical manufacturing facility, and more particularly, provided with a displacement enlarging mechanism that expands the displacement of the piezoelectric element. It relates to the improvement of things.
[0002]
[Prior art]
In recent years, pressure-type flow rate control devices have been widely used instead of mass flow controllers in semiconductor manufacturing equipment, chemical manufacturing equipment, etc., and as a piezoelectric element-driven metal diaphragm type control valve applied thereto, for example, patent literature 1 is known.
However, since such a device uses a piezoelectric element, a stroke (displacement) is very small and a fluid having a large flow rate cannot be controlled.
[0003]
By the way, as a displacement enlarging mechanism using an insulator used for a control valve, one provided in a fluid path (see Patent Document 2) and one provided outside a fluid path are known, and the latter one is known. Is further classified as follows.
(1) The support and the insulator are integrally formed, and the boundary portion is thinned to facilitate elastic deformation (see Patent Document 3, Patent Document 4, and FIGS. 4 to 7 in Patent Document 5). .
(2) The support and the insulator are separated from each other, and a housing cavity for accommodating the insulator is formed in the support, and the insulator is inserted into the accommodation cavity so as to be swingable (see Patent Document 6).
(3) The support body and the insulator body are separated from each other, and the insulator body can be moved by a support shaft (see FIGS. 1 to 3 of Patent Document 5).
[0004]
[Patent Document 1]
JP-A-7-310842 [Patent Document 2]
JP-A-8-93944 [Patent Document 3]
JP 63-199978 A [Patent Document 4]
Japanese Patent Publication No. 6-94909 [Patent Document 5]
Japanese Patent Laid-Open No. 11-257452 [Patent Document 6]
JP-A-5-99357 [0005]
However, in the case where the displacement magnifying mechanism is provided in the fluid path, the flow of the fluid is hindered by the displacement magnifying mechanism and the valve itself becomes large.
The thing of said (1) was equipped with the thin part, Therefore As it passed with time, it could break from here and was lacking in durability.
In the case of (2), since the insulator is fitted in the housing cavity, unless the fitting accuracy is high, the swing of the insulator is not fixed and the operation is not reliable.
The above (2) and (3) are not provided with a return means for returning to the original position as a displacement enlarging mechanism. Therefore, a large load is applied to the return means on the valve body side, and high-speed and high-precision operation cannot be performed.
[0006]
[Problems to be solved by the invention]
As described above, the conventional ones have advantages and disadvantages, and improvement has been desired.
The present invention was devised in view of the problems described above, and a problem to be solved by the present invention is a piezoelectric element that is highly durable and capable of high-speed and high-precision operation. It is in providing a drive type metal diaphragm type control valve.
[0007]
[Means for Solving the Problems]
The piezoelectric element drive type metal diaphragm type control valve of the present invention basically includes a valve body including an inflow path, an outflow path, and a valve seat formed therebetween, and a valve seat provided on the valve body. A metal diaphragm valve body that can be moved to and away from the valve body, a valve rod that can be moved up and down on the valve body to actuate the metal diaphragm valve body, a piezoelectric element that drives the valve rod, and between the valve rod and the piezoelectric element In the control valve provided with a displacement magnifying mechanism provided to magnify the displacement of the piezoelectric element and transmit it to the valve stem, the displacement magnifying mechanism is disposed in a vertical direction with a support attached to the valve body. A plurality of insulators, a horizontal axis that alternately supports the left and right ends of each insulator on the support, and the opposite side of the insulator except the lowest and the center of the next insulator The intermediate coupling provided between the two and the input lever provided between the central portion of the uppermost insulator and the piezoelectric element. Body, a movable body provided at the center of the lowermost lever body so as to be movable up and down, a constant pressure elastic body that elastically presses the movable body toward the valve stem with a predetermined pressure, and between the movable body and the valve stem And a return elastic body having a smaller elastic force than a constant pressure elastic body that is provided between the support body and the lowermost insulator body and returns each insulator body to its original position. Features exist.
[0008]
When the piezoelectric element is driven, the displacement of the piezoelectric element is expanded by the displacement expanding mechanism and transmitted to the metal diaphragm valve body through the valve rod. If it does so, a metal diaphragm valve body will be contact | abutted by a valve seat, valve closing will be performed, and the flow of the fluid from an inflow path to an outflow path will be interrupted | blocked.
Conversely, when the drive of the piezoelectric element is released, the metal diaphragm valve body returns to its original shape due to self-elasticity. If it does so, a metal diaphragm valve body will be separated from a valve seat, valve opening will be performed, and the flow of the fluid from an inflow path to an outflow path is permitted.
The displacement magnifying mechanism includes a plurality of insulators, an input combination, an intermediate combination, and an output combination, which perform a so-called multistage insulator action, so that the displacement of the piezoelectric element can be expanded.
Therefore, a large flow rate fluid can be controlled using a piezoelectric element having a very small stroke (displacement).
[0009]
Since the lever body of the displacement magnifying mechanism is pivotally supported by the support body by the horizontal axis, it does not break as time elapses unlike the conventional thin-walled portion, and the durability can be improved. The displacement magnifying mechanism includes a movable body and a constant pressure elastic body, which exhibit a so-called constant pressure elastic function and a buffer function, so that the metal diaphragm valve element is held against the valve seat at a constant pressure and the state is maintained. In addition, it is possible to fit the metal diaphragm valve body while buffering it to the valve seat. For this reason, damage and wear of the metal diaphragm valve body and the valve seat can be prevented.
The displacement magnifying mechanism has a return elastic body, which can return each insulator body to its original position, so that the self-elasticity function of the metal diaphragm valve body is not hindered, and the metal diaphragm valve body High-speed and high-precision operation can be performed.
[0010]
It is preferable that there are two insulators in the upper and lower sides. In this way, a large amount of displacement can be obtained with a small number, and so-called cost performance can be improved.
[0011]
The output assembly preferably includes a conical hole formed in the lower surface of the movable body, a conical hole formed in the upper surface of the valve stem, and a spherical body interposed therebetween. In this way, the displacement of the movable body can be accurately transmitted to the valve stem regardless of the state of the movable body.
[0012]
The output assembly preferably includes a flat lower surface of the movable body, a conical hole formed in the upper surface of the valve stem, and a spherical body interposed therebetween. In this way, one of the conical holes can be omitted, so that the manufacture becomes easier and the cost can be reduced.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal side view showing a piezoelectric element drive type metal diaphragm type control valve according to a first example of the present invention. FIG. 2 is an enlarged vertical side view of the main part of FIG. FIG. 3 is a perspective view of FIG. 1 showing a main part of the displacement enlarging mechanism.
[0014]
The piezoelectric element drive type metal diaphragm type control valve 1 includes a valve body 2, a metal diaphragm valve body 3, a valve rod 4, a piezoelectric element 5, and a displacement magnifying mechanism 6.
[0015]
The displacement enlarging mechanism 6 is provided between the valve rod 4 and the piezoelectric element 5 to enlarge the displacement of the piezoelectric element 5 and transmit the displacement to the valve rod 4. The support 7, the insulator 8, the horizontal shaft 9, An intermediate coupling body 10, an input coupling body 11, a movable body 12, a constant pressure elastic body 13, an output coupling body 14, and a return elastic body 15 are provided.
[0016]
The valve body 2 includes an inflow path 16, an outflow path 17, and a valve seat 18 formed therebetween. In this example, the valve body 2 is made of stainless steel and is divided into left, right, and center, A bolt 19 for combining them, an inflow path 16 formed in the left and center valve bodies 2, an outflow path 17 formed in the center and right valve bodies 2, and a central valve body 2 communicating with them. A valve chamber 20 formed open at the top, an upward valve seat 18 formed between the inflow passage 16 and the outflow passage 17, and between the left and center valve bodies 2 and the center. A cylindrical guide 21 is provided between the right valve main body 2 to position them, and a gasket 22 is provided on the inner side to seal the inflow path 16 and the outflow path 17.
[0017]
Since the valve body 2 is used as a control valve for a pressure type flow rate control device, a sensor chamber 23 is formed in the central valve body 2 that is open at the bottom and communicates with the outflow passage 17. A pressure sensor 24 that detects the pressure of the fluid in the outflow passage 17, a lower lid 25 that closes the sensor chamber 23, and a bolt 26 that is detachably attached to the central valve body 2 are provided.
[0018]
The metal diaphragm valve body 3 is provided on the valve body 2 and can be separated from the valve seat 18. In this example, the metal diaphragm valve body 3 is formed by two diaphragms made of nickel alloy, and the central portion is slightly upward. Inverted dish shape that bulges out.
The outer peripheral edge of the metal diaphragm valve body 3 is pressed and fixed via a presser adapter 29 by a base presser 28 which is detachably attached to the valve body 2 by bolts 27 and closes the valve chamber 20.
[0019]
The valve stem 4 is provided on the valve main body 2 so as to be movable up and down, and operates the metal diaphragm valve body 3. In this example, the valve stem 4 is provided so as to be movable up and down through the base presser 28. A cylindrical bush 30 is interposed between them.
A diaphragm presser 31 for pressing the central portion of the metal diaphragm valve element 3 is provided at the lower portion of the valve stem 4.
[0020]
The piezoelectric element (piezoactuator) 5 is provided in the valve body 2 and drives the valve stem 4. In this example, the piezoelectric element (piezoactuator) 5 is a laminated type, and is provided with a connector 32 at the upper portion. Housed inside.
[0021]
The support cylinder 33 has a cylindrical shape, and a lower part thereof is screwed onto an upper part of the support 7 of the displacement magnifying mechanism 6 and is locked by a lock nut 34. The lock nut 36 which locks is screwed together.
A bearing (thrust bearing) 37 and a bearing receiver 38 are interposed between the upper portion of the piezoelectric element 5 and the adjustment cap nut 35 for smooth rotation of the nut.
[0022]
A protective case 39 is provided outside the piezoelectric element 5, and a control circuit 40 for the piezoelectric element is provided inside the protective case 39.
[0023]
The support body 7 is attached to the valve body 2, and in this example, a lever box 41 having a box shape with the upper side and the left side opened, a box flange 42 closing the upper side, and an appropriate combination of them. A number of bolts 43 are provided.
The lever box 41 includes a through hole 44 formed at the center of the bottom wall and facing the valve stem 4, and bearing holes 45 formed diagonally apart on the front and rear side walls. And is fixed by bolts 46.
The box flange 42 is formed with a screw hole in the center, and the lower portion of the support cylinder 33 is screwed.
[0024]
A plurality of the insulators 8 are arranged in the vertical direction. In this example, the insulator body 8 has two upper and lower parts, has a flat plate shape, the upper one is short, and the shaft hole 47 is formed at the right end. In addition, the lower one is long and the shaft hole 47 is formed at the left end.
[0025]
The horizontal axis 9 is one in which the left and right ends of each insulator 8 are alternately pivotally supported on the support 7. In this example, the upper and lower horizontal axes 9 are arranged in correspondence with the insulator 8. Is inserted into the shaft hole 47 of the upper lever body 8 and the upper right bearing hole 45 of the support body 7 to pivotally support the right end portion of the upper lever body 8, and the lower horizontal shaft 9 The shaft hole 47 of the body 8 and the lower left bearing hole 45 of the support 7 are inserted to pivotally support the left end portion of the lower lever body 8.
A bearing (radial bearing) 48 is interposed between each horizontal shaft 9 and the bearing hole 45 of the support 7.
[0026]
The intermediate combined body 10 is provided between the side opposite to the pivotal side of the lever body 8 except the lowermost part and the central portion of the next-stage lever body 8, and in this example, the upper lever body 8 And a cylindrical pin 50 which is fitted in the groove 49 and can be brought into contact with the upper surface closer to the left side from the center of the lower lever body 8.
[0027]
The input assembly 11 is provided between the center portion of the uppermost insulator 8 and the piezoelectric element 5. In this example, the input hole 11 includes a conical hole 51 formed on the upper surface of the center portion of the upper insulator 8. , And a hemispherical body 52 fitted to the lower portion of the piezoelectric element 5.
[0028]
The movable body 12 is provided at the central portion of the lowermost lever body 8 so as to be movable up and down. In this example, the movable body 12 has a stepped shaft shape and is drilled from the center of the lower lever body 8 toward the right side. The stepped through hole 53 is inserted from below, and a screw 54 is screwed from above to prevent the through hole 53 from coming off. A recess 55 for avoiding interference with the head of the screw 54 is formed on the lower center surface of the upper insulator 8.
[0029]
The constant pressure elastic body 13 elastically presses the movable body 12 toward the valve rod 4 with a predetermined pressure. In this example, the constant pressure elastic body 13 is a plurality of disc springs, and is arranged in the large diameter portion of the through-hole 53 and is placed in a lower position. It is interposed between the insulator 8 and the movable body 12.
[0030]
The output coupling 14 is provided between the movable body 12 and the valve stem 4. In this example, the output coupling 14 is formed on the conical hole 56 formed on the lower surface of the movable body 12 and the upper surface of the valve stem 4. A conical hole 57 and a sphere 58 inserted between them are provided.
[0031]
The return elastic body 15 is provided between the support body 7 and the lowermost lever body 8 and has a smaller elastic force than the constant pressure elastic body 13 that returns each lever body 8 to its original position. It is a spring and is arranged in a spring receiving hole 59 formed on the lower right side surface of the lower lever body 8 and is interposed between the lower lever body 8 and the support body 7.
[0032]
Next, the operation will be described based on such a configuration.
The piezoelectric element 5 expands by a set value (between 0 and 60 μm) when a valve opening signal (input voltage 0 to 120 V) is input from the control circuit 40 via the connector 32.
When the piezoelectric element 5 is driven, the displacement of the piezoelectric element 5 is expanded by the displacement expanding mechanism 6 and transmitted to the metal diaphragm valve body 3 through the valve rod 4. Then, the central portion of the metal diaphragm valve element 3 is brought into contact with the valve seat 18 to close the valve, and the flow of fluid from the inflow path 16 to the outflow path 17 is blocked.
Conversely, when the valve opening signal to the piezoelectric element 5 is canceled, the piezoelectric element 5 returns to its original length, and the metal diaphragm valve element 3 returns to its original shape due to self-elasticity. Then, the central portion of the metal diaphragm valve body 3 is opened from the valve seat 18, and fluid flow from the inflow path 16 to the outflow path 17 is allowed.
[0033]
The displacement enlarging mechanism 6 includes two insulators 8, an input combination 11, an intermediate combination 10, and an output combination 14, which perform a so-called multistage lever action, and thus the displacement amount of the piezoelectric element ( 0 to 60 μm) can be enlarged to an enlargement amount (0 to 220 μm).
Therefore, a large flow rate fluid can be controlled by using the piezoelectric element 5 having a very small stroke (displacement).
[0034]
Since the insulator 8 of the displacement magnifying mechanism 6 is pivotally supported by the support 7 by the horizontal shaft 9, it does not break as time elapses unlike the conventional thin-walled portion, and the durability can be improved. it can.
The displacement enlarging mechanism 6 is provided with a movable body 12 and a constant pressure elastic body 13, which exhibit a so-called constant pressure elastic function and a buffering function. This state can be maintained, and the metal diaphragm valve element 3 can be matched with the valve seat 18 while being buffered. For this reason, damage to the metal diaphragm valve body 3 and the valve seat 18 can be prevented. In addition, the movable body 12 and the constant pressure elastic body 13 also exhibit the alignment function of the output coupling 14 and can appropriately transmit the displacement of the movable body 12 to the valve stem 4.
The displacement magnifying mechanism 6 includes a return elastic body 15, which can return each insulator body 8 to its original position, so that the self-elasticity function of the metal diaphragm valve body 3 is not hindered, and the metal The diaphragm valve body 3 can be operated at high speed and with high accuracy.
[0035]
Next, a second example of the present invention will be described with reference to FIG.
FIG. 4 is an enlarged longitudinal sectional side view showing the vicinity of the displacement enlarging mechanism of the piezoelectric element drive type metal diaphragm type control valve according to the second example of the present invention.
[0036]
In the second example, the output assembly 14 is constituted by a flat lower surface 60 of the movable body 12, a conical hole 57 formed in the upper surface of the valve stem 4, and a spherical body 58 interposed therebetween, so-called. The difference from the first example is that the conical hole 56 formed on the lower surface of the movable body 12 is omitted, and the other points are the same as in the first example.
In such a case, since it is not necessary to form the conical hole 56 in the movable body 12, the manufacture is simplified and the cost can be reduced.
[0037]
The number of the insulators 8 is two in the previous example, but is not limited to this, and may be three or more, for example.
In the previous example, the intermediate assembly 10 is constituted by the concave groove 49 and the pin 50, but is not limited thereto, and is constituted by, for example, only a hemisphere or a semi-cylindrical body attached to the lower left surface of the upper insulator 8. Also good.
[0038]
【The invention's effect】
As described above, according to the present invention, the following excellent effects can be obtained.
(1) Consists of a valve body, a metal diaphragm valve body, a valve rod, a piezoelectric element, and a displacement magnifying mechanism. In particular, the displacement magnifying mechanism includes a support attached to the valve body and a plurality of insulators arranged in the vertical direction. Between the body, the horizontal axis that alternately supports the left and right ends of each insulator on the support, and the opposite side of the insulator except the lowest, and the center of the next insulator The intermediate assembly provided, the input assembly provided between the central portion of the uppermost insulator and the piezoelectric element, and the movable member provided so as to be able to be raised and lowered and moved in the center of the lowermost insulator. A constant-pressure elastic body that elastically presses the movable body toward the valve rod side with a predetermined pressure, an output assembly provided between the movable body and the valve rod, and a support body and a lowermost insulator body. Because it is equipped with a return elastic body that has a smaller elastic force than a constant pressure elastic body that returns each insulator body to its original position, it has excellent durability. High-speed and high-precision operation can be performed.
[Brief description of the drawings]
FIG. 1 is a longitudinal side view showing a piezoelectric element driven metal diaphragm type control valve according to a first example of the present invention.
2 is an enlarged longitudinal sectional side view of the main part of FIG. 1 showing the vicinity of a displacement enlarging mechanism.
FIG. 3 is a perspective view of FIG. 1 showing a main part of the displacement enlarging mechanism.
FIG. 4 is an enlarged vertical sectional side view showing the vicinity of a displacement enlarging mechanism of a piezoelectric element drive type metal diaphragm type control valve according to a second example of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Piezoelectric element drive type metal diaphragm type control valve, 2 ... Valve body, 3 ... Metal diaphragm valve body, 4 ... Valve rod, 5 ... Piezoelectric element, 6 ... Displacement expansion mechanism, 7 ... Support body, 8 ... Insulator body, DESCRIPTION OF SYMBOLS 9 ... Horizontal axis, 10 ... Intermediate | middle fitting, 11 ... Input fitting, 12 ... Movable body, 13 ... Constant pressure elastic body, 14 ... Output fitting, 15 ... Return elastic body, 16 ... Inflow path, 17 ... Outflow path, 18 ... Valve seat, 19, 26, 27, 43, 46 ... Bolt, 20 ... Valve chamber, 21 ... Guide, 22 ... Gasket, 23 ... Sensor chamber, 24 ... Pressure sensor, 25 ... Lower lid, 28 ... Base presser, 29 ... Presser adapter, 30 ... Bush, 31 ... Diaphragm presser, 32 ... Connector, 33 ... Supporting cylinder, 34, 36 ... Lock nut, 35 ... Adjusting cap nut, 37, 48 ... Bearing, 38 ... Bearing receiver, 39 ... Protective case, 40 ... Control times , 41 ... lever box, 42 ... box flange, 44 ... through hole, 45 ... bearing hole, 47 ... shaft hole, 49 ... concave groove, 50 ... pin, 51, 56, 57 ... conical hole, 52 ... hemisphere, 53 ... through hole, 54 ... screw, 55 ... recess, 58 ... sphere, 59 ... spring receiving hole, 60 ... lower surface.

Claims (4)

A valve body provided with an inflow path, an outflow path, and a valve seat formed between them, a metal diaphragm valve body that is provided in the valve body and can be moved to and away from the valve seat, and can be moved up and down in the valve body A valve rod that operates the metal diaphragm valve body, a piezoelectric element that drives the valve rod, and a displacement enlarging mechanism that is provided between the valve rod and the piezoelectric element to expand the displacement of the piezoelectric element and transmit it to the valve rod The displacement enlarging mechanism includes a support body attached to the valve body, a plurality of insulator bodies arranged in the vertical direction, and a support body that alternately supports the left and right ends of each insulator body. A horizontal axis that pivots to the center, an intermediate coupling provided between a side opposite to the pivotal side of the plurality of levers excluding the lowest and a central part of the next stage, The input assembly provided between the central part of the upper insulator and the piezoelectric element, and the raising and lowering and swinging to the center of the lowermost insulator A movable body provided in the function, a constant-pressure elastic body that elastically presses the movable body to the valve rod side with a predetermined pressure, an output assembly provided between the movable body and the valve rod, a support and the lowest A piezoelectric element-driven metal diaphragm type control valve comprising: a return elastic body having a smaller elastic force than a constant pressure elastic body provided between the insulator bodies and returning each insulator body to its original position. The piezoelectric element drive type metal diaphragm type control valve according to claim 1, wherein the number of insulators is two. The output coupling body includes a conical hole formed in the lower surface of the movable body, a conical hole formed in the upper surface of the valve stem, and a spherical body interposed therebetween. Piezoelectric element driven metal diaphragm type control valve. 3. The piezoelectric element drive type according to claim 1, wherein the output coupling body includes a flat lower surface of the movable body, a conical hole formed in the upper surface of the valve stem, and a spherical body interposed therebetween. Metal diaphragm type control valve.

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