JP4287935B2 - Piezo type flow control valve drive structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a piezo-type flow regulating valve drive unit structure.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a method of directly converting electric power into an operation amount of a valve body using a piezo stack composed of piezo elements stacked on a drive unit of a flow rate adjusting valve has been used. FIG. 4 is a cross-sectional view showing a configuration of a conventional piezo drive type flow rate adjusting valve 11.
[0003]
In FIG. 4, reference numeral 12 denotes a piezo actuator, one end side 12 </ b> A of which is in contact with the valve element operating unit 13 via the ruby ball B. 14 is a cap nut fixed to the other end 12 </ b> B of the piezo actuator 12, 14 a is a stop nut for positioning the cap nut 14, and 15 is a substantially cylindrical shape that is fixedly erected on the valve body 16 of the flow regulating valve 11. This is a fixed cylinder.
[0004]
In the flow rate adjusting valve 11 having the above-described configuration, the cap nut 14 is screwed and connected to the fixed cylinder 15 so that the piezo actuator 12 is inserted into the fixed cylinder 15, and the piezo actuator 12 presses the valve body operating unit 13. The valve element operating unit 13 can be driven and operated in the closing direction by applying voltage to the piezo actuator 12 and expanding the piezoelectric actuator 12 with the positioning nut 14a tightened and fixed at a good position.
[0005]
Further, since the piezo actuator 12 dislikes moisture, the piezo stack 17 inside the piezo actuator 12 is inserted into a bush 18 filled with dry nitrogen, for example, and is blocked from outside air.
[0006]
[Problems to be solved by the invention]
However, in the configuration of the conventional flow rate adjustment valve 11, the displacement amount of the piezo actuator 12 is output by the variation in the distance between the both ends 12 </ b> A and 12 </ b> B of the piezo actuator 12. Therefore, when used for the flow rate adjusting valve 11, it is necessary to provide a fixing tubular member such as the fixed cylinder 15.
[0007]
For this reason, when the length of the piezo stack 17 is changed in order to change the operation amount of the flow regulating valve 11, it is necessary to change the length of the fixed cylinder 15 at the same time. That is, it is necessary to prepare the fixed cylinder 15 having the same number of variations as the variation of the length of the piezoelectric actuator 12. In other words, the conventional configuration has a problem that many parts and labor are required for mounting the piezoelectric actuator 12.
[0008]
Further, in the conventional configuration, the piezo actuator 12 is covered with the fixed cylinder 15, so that even if a cooling fan is provided around the piezo actuator 12 to cool the piezo actuator 12, the piezo actuator 12 in the fixed cylinder 15 is effectively provided. It is difficult to cool, and there is a problem that heat dissipation must be deteriorated when used at a high temperature.
[0009]
Further, in the above-described conventional configuration, the flow rate is adjusted by the overall expansion of the piezo actuator 12, so that the change in the operation amount due to the temperature expansion of the piezo actuator 12 and the change due to the thermal expansion of the fixed cylinder 15 and the like are compatible. I did not. In particular, the expansion coefficient changes between an unloaded state and a state where force is applied, and in order to obtain a configuration in which the change in the operation amount due to temperature expansion is small in the above-described conventional configuration, the material selection of the fixed cylinder 15 is selected. Was extremely difficult.
[0010]
The present invention has been made in consideration of such circumstances, and it is possible to reduce the number of parts in the connection portion of the piezo actuator, improve the heat dissipation efficiency of the piezo stack, and further improve the temperature characteristics and durability. An object of the present invention is to provide a piezo-type flow regulating valve drive unit structure.
[0011]
[Means for Solving the Problems]
That is, the piezoelectric flow control valve drive unit structure of the present invention has a piezo stack housed in a cylindrical metal case provided with an outward flange at one end, and one end of the piezo stack is connected to the metal stack. A piezo actuator fixed to a lid member fixed to the other end of the case, and configured such that expansion deformation of the piezo stack by application of voltage is interlocked with opening and closing of a valve; and the flange of the metal case The outer periphery of the diaphragm covering the one end is fixed, and the other end of the piezo stack is attached to one surface of the diaphragm, and this diaphragm is accompanied by expansion deformation of the piezo stack due to voltage application. while the center portion of the diaphragm is deformed so as to be separated from the lid member than the outer peripheral portion, the outward flange A fixed top plate formed with through holes provided in the stacking direction of the piezo elements constituting the piezo stack, and the center portion of the diaphragm supported by the fixed top plate. A second valve body operation reversing tool having a support portion and connected to the valve body having the valve; a bottom surface for operating the valve body operation portion of the valve body; A cap nut receiver is provided with a thread groove through which the cap nut is threaded. The elastic member inserted between the bottom surface and the fixed top plate is biased toward the valve body operating portion. The first valve element operation reversing tool that is in a state in which it can move in the stacking direction of the piezo elements without being removed from the second valve element operation reversing tool by screwing the cap nut into the thread groove. Piezo actuator is the valve body Attached to the outer peripheral portion of the diaphragm, displacement output portions are provided to be displaced in the stacking direction of the piezoelectric element in accordance with the expansion deformation of the piezo stack by the application of voltage, in the center of the diaphragm, due to the application of the voltage A fixed portion that is not displaced in the stacking direction of the piezo elements is provided in association with the expansion and deformation of the piezo stack, and the displacement of the displacement output portion is configured to be interlocked with opening and closing of the valve .
The piezoelectric flow control valve drive unit structure of the present invention has a piezoelectric stack housed in a cylindrical metal case having an outward flange at one end, and one end of the piezoelectric stack is connected to the metal stack. A piezo actuator fixed to a lid member fixed to the other end of the case, and configured such that expansion deformation of the piezo stack by application of voltage is interlocked with opening and closing of a valve; and the flange of the metal case The outer periphery of the diaphragm covering the one end is fixed, and the other end of the piezo stack is attached to one surface of the diaphragm, and this diaphragm is accompanied by expansion deformation of the piezo stack due to voltage application. while the center portion of the diaphragm is deformed so as to be separated from the lid member than the outer circumferential portion, directly to the outward flange Or a cap nut that is indirectly engaged via an annular spacer that is externally fitted to the metal case, and a member that has a screw groove that is directly fixed to the valve body having the valve and screwed into the cap nut. The piezo actuator is attached to the valve body, and the central part of the diaphragm is displaced in the stacking direction of the piezo elements along with the expansion and deformation of the piezo stack due to the application of voltage, and the valve body operation part of the valve body is moved. Displacement output locations to be operated are provided, and fixed locations that are not displaced in the stacking direction of the piezo elements in accordance with the expansion and deformation of the piezo stack due to the application of voltage are provided on the outer periphery of the diaphragm. Is configured to be interlocked with the opening and closing of the valve.
[0012]
That is, by using a piezo actuator in which the fixed portion and the displacement output portion are located on the same one end side, the structure for fixing the piezo actuator can be simplified as much as possible. In addition, since there is no member that covers the piezo actuator as in the past with the piezo actuator connected to the valve body, the piezo actuator is open without being covered by other members when cooling by air cooling or the like. The heat dissipation effect of the stack can be expected.
[0013]
Further, the operation amount of the piezo actuator can be changed, so that the number of parts can be reduced and the mounting operation can be simplified. Further, by adjusting so that the influence of thermal expansion is eliminated by the piezo actuator alone, the influence of thermal expansion due to temperature is reduced even when the piezo actuator is attached to the drive unit of the flow rate adjusting valve. That is, since the influence of the flow rate adjustment opening due to temperature is small, the accuracy of the flow rate adjustment valve can be easily improved.
[0014]
[0015]
DETAILED DESCRIPTION OF THE INVENTION
1 and 2 show an example of a piezo-type flow regulating valve drive unit structure according to the present invention. FIG. 1 is a longitudinal sectional view and FIG. 2 is an exploded perspective view. In FIG. 1, 1 is a piezo actuator, 2 is a valve body, 3 is a cap nut for mounting the piezo actuator 1, 4 is a cap nut holder, and 5 is attached to the cap nut holder 4 to reverse the operation direction of the valve body. This is an operation reversal mechanism.
[0016]
The piezo actuator 1 includes a piezo stack 6 formed by stacking a plurality of piezo elements that expand and deform under application of a voltage, a lid member 7 that fixes an upper end portion of the piezo stack 6, and a lid member 7 that is fixed to the lid member 7. And a diaphragm 9 having an outer peripheral portion 9a attached to the lower end portion of the metal case 8 and a central portion 9b attached to the lower end portion of the piezo stack 6, and one end portion (lower end portion) thereof. An outward flange 1a is formed on 1A. The lid member 7, the metal case 8, and the diaphragm 9 are attached in an airtight manner, and, for example, dry nitrogen is sealed inside.
[0017]
In the present example, the piezoelectric actuator 1 has a fixed portion at the center portion 9b and a displacement output portion at the outer peripheral portion 9a, and both portions 9a and 9b are formed on one end side 1A in the longitudinal direction of the piezoelectric actuator 1.
[0018]
The valve body 2 includes an orifice-integrated valve block 2a and a diaphragm 2b attached to the upper surface of the orifice of the valve block 2a, and a valve body operating portion 2c is integrally formed with the diaphragm 2b. . And the valve is comprised by the orifice and diaphragm 2b which were formed in the valve block 2a. Further, the valve body operating portion 2c is applied with force in the valve opening direction by, for example, a coil spring 2d.
[0019]
The cap nut 3 has an inner diameter slightly larger than the outer diameter of the metal case 8 of the piezo actuator 1 and is configured to engage with the flange 1a. The cap nut holder 4 is fixedly attached to the upper surface of the valve block 2a, and has a cylindrical portion 4a erected concentrically on the central axis of the valve body operating portion 2c. A female screw 51a described later and a male screw 4b that can be screwed into a cap nut 3 ′ shown in FIG.
[0020]
The operation reversing mechanism 5 is roughly divided into a first valve body operation reversing tool 50, a second valve body operation reversing tool 51, an elastic body 52 inserted between both valve body operation reversing tools 50, 51, and It consists of a receiving member 53 of the piezo actuator 1 attached above the one-valve element operation reversing tool 50.
[0021]
The first valve body operation reversing tool 50 is inserted into the cylindrical portion 4a of the cap nut holder 4 so as to be slidable in the vertical direction, and operates the valve body operation portion 2c, and the outer peripheral portion of the bottom surface 50a. For example, there are four columnar guides 50b that are erected from above, and a cap nut receiver 50c that is formed on an extension line of the guide 50b and has a thread groove 50d on the outer peripheral portion. That is, the cap nut receiver 50c is provided so as to be connected to the valve body operating portion 2c. In the present example, the guide 50b is four struts projecting upward from the periphery of the bottom surface 50a. However, the present invention is not limited to this, and may be a cylindrical shape, for example. Further, the number of cap nut receivers 50c is not limited.
[0022]
The second valve element operation reversing tool 51 is a fixed top plate in which a female screw 51a screwed into a male screw 4b provided on the outer periphery of the cylindrical portion 4a and a through hole 51c into which the cap nut receiver 50c can be inserted. 51b and a support portion 51d of the piezo actuator 1 erected at the center of the fixed top plate 51b (coaxially with the valve body operating portion 2c). That is, the support portion 51d of the piezo actuator 1 is fixed to the female screw 51a. Further, after adjusting the screwing position of the female screw 51a, it can be fixed by tightening the positioning nut 51e.
[0023]
The elastic body 52 includes, for example, a coil spring 52a and a spring receiver 52b of the coil spring 52a, and is inserted between the fixed top plate 51b and the bottom surface 50a. The elastic force of the coil spring 52a is stronger than the elastic force of the coil spring 2d, and the flow rate adjusting valve is always kept closed (in a non-energized state).
[0024]
The receiving tool 53 engages with the upper end of the first valve element operation reversing tool 50, and forms a through hole 53 a through which the support tool 51 d can be inserted, and the outer periphery of one end side 1 </ b> A of the piezo actuator 1. It has the receiving part 53b contact | abutted to a part.
[0025]
Therefore, the elastic body 52 is inserted on the bottom surface 50 a of the first valve element operation reversing tool 50, and the cap nut receiver 50 c of the first valve element operation reversing tool 50 is inserted into the through hole 51 c of the second valve element operation reversing tool 51. The piezo actuator 1 is screwed and connected to the bag nut receiver 50c by the bag nut 3 with the holder 53 attached to the upper part of the bag nut receiver 50c. Next, the piezoelectric actuator 1 can be attached to the valve main body 2 by screwing the female screw 51a of the second valve element operation reversing tool 51 into the male screw 4b.
[0026]
Note that a sphere B made of ruby is sandwiched between the fixing portion 9b of the piezo actuator 1 and the support 51d, between the spring receiver 52b and the bottom surface 50a, and between the bottom surface 50a and the valve body operating portion 2c. Yes. In other words, the ruby ball B is interposed at each center, thereby minimizing the displacement of the center. The female screw 51a of the second valve element operation reversing tool 51 is adjusted so that the bottom surface 50a of the first valve element operation reversing tool 50 is in contact with the valve element operation portion 2c via the ball B and has a predetermined displacement. It will be fixed later.
[0027]
Since the piezo actuator 1 attached as described above is attached to the valve body 2 via the operation reversing mechanism 5, the flow regulating valve is closed in a non-energized state. When a voltage is applied to the piezo stack 6, the lid member 7 and the metal case 8 are displaced upward in accordance with the displacement (elongation) of the piezo stack 6, and accordingly, the displacement output location 9a of the diaphragm 9 is displaced upward. At the same time, the cap nut 3, the first valve body operation reversing tool 50, and the receiving tool 53 are displaced upward, and the valve body operation portion 2c is moved upward, so that the flow rate adjusting valve is opened. That is, it is possible to control to open the flow rate adjustment valve as the piezo actuator 1 expands, and it is possible to provide a normally closed type flow rate adjustment valve that opens when a voltage is applied.
[0028]
Further, since the piezoelectric actuator 1 having the above-described configuration is fixed only at one end side 1A, it can be fixed using the same cap nut 3 regardless of the length of the piezoelectric actuator 1. Therefore, when changing the operation amount by changing the length of the piezo actuator 1, not only can the mounting work be simplified, but it is also necessary to prepare a plurality of members 15 corresponding to the length of the piezo actuator 1 as in the prior art. The manufacturing cost can be reduced accordingly.
[0029]
In addition, by fixing the piezo actuator 1 on its one end side 1A as in the present invention, a member (a member such as the fixed cylinder 15 of the conventional example) that becomes an unnecessary cover for the piezo actuator 1 is eliminated. Can do. That is, when the piezo actuator 1 is cooled, the cooling efficiency can be improved, and the temperature can be lowered by about 50 to 100 ° C. by forced cooling.
[0030]
Further, the piezoelectric actuator 1 described above can be adjusted so that the influence of thermal expansion is eliminated by the piezoelectric actuator 1 alone by combining the thermal expansion coefficient of the piezoelectric stack 6 and the thermal expansion coefficient of the metal case 8. In other words, by attaching the piezo actuator 1 adjusted so as to eliminate the influence of thermal expansion to the drive unit of the flow rate adjustment valve, it is possible to eliminate the influence of the temperature on the flow rate adjustment opening degree. Accuracy can be improved easily.
[0031]
FIG. 3 shows another example of the present invention. The configuration and operation will be described with reference to FIG. 3 together with FIG. In addition, since the member which attached | subjected the code | symbol same as the code | symbol used by the above-mentioned description is the same member, the detailed description is abbreviate | omitted.
[0032]
In FIG. 2, 3 ′ is a cap nut that can be screwed into the cylindrical portion 4a, 10 is a spacer having an inner diameter slightly larger than the outer diameter of the metal case 8, and an outer diameter slightly smaller than the inner diameter of the cylindrical portion 4a. 51e is a positioning nut for the cap nut 3 '. The piezo-type flow regulating valve drive unit structure of this example is obtained by removing the operation reversing mechanism 5 from the piezo-type flow regulating valve drive unit structure shown in FIG. 1 and inserting a spacer 10 instead.
[0033]
That is, as shown in FIG. 3, the spacer 10 can be engaged with the flange 1 a of the piezoelectric actuator 1 by inserting the spacer 10 through the metal case 8. The piezo actuator 1 can be fixed to the valve body 2 by screwing the cap nut 3 ′ with the male screw 4 a in a state where the cap nut 3 ′ is engaged with the spacer 10.
[0034]
In the piezo-type flow rate adjusting valve driving portion structure of this example, the outer peripheral portion 9a on one end side 1A of the piezo actuator 1 is a fixed portion, and the central portion 9b is a displacement output portion. And the displacement output location 9b operates the valve body operation part 2c via the ball B of ruby. In this example as well, the operating position of the piezo actuator 1 relative to the valve body operating portion 2c can be adjusted by the threaded position of the cap nut 3 'relative to the male screw 4a. It is also possible to fix the adjusted position using the positioning nut 51e.
[0035]
According to the piezo-type flow regulating valve drive unit structure of this example, the valve body operating unit 2c is pulled upward by the coil spring 2d, and the flow regulating valve is opened (normally closed) in a non-energized state. When a voltage is applied to the piezo stack 6, the displacement output location 9b is displaced downward, and the flow rate adjusting valve can be closed.
[0036]
That is, by using the piezo-type flow rate adjusting valve drive unit structure of the present invention, the common piezo actuator 1, the valve body 2, and the valve body in both the normally open type flow rate adjusting valve and the normally closed type flow rate adjusting valve. The operation part 2c, the diaphragm 2b, the cap nut holder 4, and the positioning nut 51e can be used. Further, the piezoelectric actuator 1 can be mounted in the same manner regardless of the length of the piezoelectric actuator 1. That is, by using common parts for all types of piezo-type flow control valve drive unit structures, it is possible to achieve reductions in production costs and simplification of various operations such as replacement work.
[0037]
In addition, the same effect as that of the example shown in FIG. 1 can be obtained in that the cooling efficiency of the piezoelectric actuator 1 is improved. Further, by assembling the piezo actuator 1 that has been subjected to temperature compensation, it is possible to improve the accuracy by removing the influence of the heat on the flow regulating valve.
[0038]
In the above example, the spacer 10 is provided to adjust the depth of attachment of the piezo actuator 1 with the cap nut 3 screwed to the male screw 4b. Depending on the case, the spacer 10 may be eliminated.
[0039]
【The invention's effect】
As described above in detail, according to the present invention, the structure for fixing can be simplified as much as possible by using the piezoelectric actuator in which the fixing portion and the displacement output portion are located on the same one end side. Since the piezo actuator is opened without being covered with other members, the heat dissipation effect of the piezo stack can be expected. In addition, the number of parts is reduced. Furthermore, the accuracy of the flow rate adjusting valve can be easily improved by using a piezo actuator that is adjusted so that the influence of thermal expansion is eliminated.
[0040]
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a main part of a piezo-type flow regulating valve drive unit structure of the present invention.
FIG. 2 is an exploded perspective view of the piezo-type flow rate adjusting valve driving unit structure.
FIG. 3 is a longitudinal sectional view showing another example of a piezo-type flow regulating valve driving unit structure.
FIG. 4 is a longitudinal sectional view showing a configuration of a conventional piezo-type flow rate adjusting valve driving unit structure.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Piezo actuator, 1a ... Flange, 1A ... One end side, 2 ... Valve body, 2a ... Valve body operation part, 3 ... Cap nut, 4 ... Cap nut holder, 4a ... Cylindrical part, 4b ... Male screw, 5 ... operation reversing mechanism, 50c ... cap nut receiver, 51a ... female screw, 51d ... support part, 9 ... diaphragm.

Claims (2)

A piezo stack is housed in a cylindrical metal case having an outward flange at one end, and one end of the piezo stack is fixed to a lid member fixed to the other end of the metal case. A piezoelectric actuator configured such that expansion deformation of the piezo stack by application of the valve is interlocked with opening and closing of the valve;
The outer periphery of the diaphragm covering the one end is fixed to the flange of the metal case, and the other end of the piezo stack is attached to one surface of the diaphragm. The diaphragm is formed by applying a voltage to the piezo. As the stack expands and deforms, the center portion of the diaphragm is deformed so as to be farther from the lid member than the outer peripheral portion, and the cap nut that directly engages the outward flange and the piezo stack are configured. A fixed top plate in which through holes provided in the stacking direction of the piezoelectric elements are formed, and a support portion that is erected on the fixed top plate and supports the central portion of the diaphragm, and is connected to the valve body having the valve The second valve element operation reversing tool, the bottom surface for operating the valve element operation portion of the valve body, and the through hole of the fixed top plate standing from the bottom surface Through a cap nut receiver provided with a thread groove into which the cap nut is threaded, is urged toward the valve body operating portion side by an elastic body inserted between the bottom surface and the fixed top plate, The first valve element operation reversing tool that is not removed from the second valve element operation reversing tool and is movable in the stacking direction of the piezo elements by being screwed into the thread groove, thereby allowing the piezo actuator to move the valve. Attached to the body,
Displacement output locations that displace in the stacking direction of the piezo elements in accordance with expansion and deformation of the piezo stack due to application of voltage are provided on the outer periphery of the diaphragm, and the piezo stack due to application of voltage is provided at the center of the diaphragm. A fixed portion that does not displace in the stacking direction of the piezo elements with the expansion deformation of is provided,
A piezo-type flow rate adjusting valve drive unit structure characterized in that the displacement of the displacement output location is linked to the opening and closing of the valve. A piezo stack is accommodated in a cylindrical metal case having an outward flange at one end, and one end of the piezo stack is fixed to a lid member fixed to the other end of the metal case. A piezoelectric actuator configured such that expansion deformation of the piezo stack by application of the valve is interlocked with opening and closing of the valve;
An outer peripheral portion of a diaphragm covering the one end is fixed to the flange of the metal case, and the other end of the piezo stack is attached to one surface of the diaphragm. As the stack expands and deforms, the center portion of the diaphragm is deformed so as to be separated from the lid member rather than the outer peripheral portion, while an annular spacer that is fitted directly on the outward flange or on the metal case is provided. The piezo actuator is attached to the valve main body by a cap nut indirectly engaged via a member having a thread groove that is directly fixed to the valve main body having the valve and screwed into the cap nut,
A displacement output location is provided at the center of the diaphragm for operating the valve body operating portion of the valve body by displacing in the stacking direction of the piezo elements with the expansion and deformation of the piezo stack due to application of voltage. On the outer periphery, a fixed portion that is not displaced in the stacking direction of the piezo elements with the expansion and deformation of the piezo stack due to the application of voltage is provided,
A piezo-type flow rate adjusting valve drive unit structure configured to interlock the displacement of the displacement output location with the opening and closing of the valve.