JP2015023588A - Displacement magnification device and flow control valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a displacement magnification device which is downsized, magnifies displacement of a piezoelectric actuator and transfers the magnified displacement without waste, and a flow control valve with the displacement magnification device.SOLUTION: The displacement magnification device includes a first piezoelectric actuator 2 connected to a diaphragm structure 12 via a first connection ball 6; and a first piezoelectric actuator 1 connected to a fixing pedestal 11 via a second connection ball 7. Between the second piezoelectric actuator 2 and the first piezoelectric actuator 1, a column support 3 is disposed in parallel to both actuators. One end of the column support 3 is fixed to the fixing pedestal 11 and in the other end of the column support 3, an arm 5 is provided which perpendicularly extends to both sides of the column support 3. One-side ends of the second piezoelectric actuator 2 and the first piezoelectric actuator 1 are connected to the arm 5 via third connection balls 8a and 8b, respectively.

Description

  The present invention relates to a displacement magnifying device for a piezoelectric actuator and a flow control valve.

  A piezoelectric actuator is a device that obtains a driving force by generating a mechanical displacement by applying a voltage to a piezoelectric element. This piezoelectric actuator is used as a drive source of a flow control valve of a mass flow controller, for example.

  A flow control valve used for flow control of a fluid such as gas or liquid is often used in an environment where reliability such as humidity resistance is required. For this reason, piezoelectric actuators that achieve a long life and high performance by encapsulating the piezoelectric element in a stretchable metal case and protecting it from moisture resistance and external stress are used. Such a configuration of the flow control valve is disclosed in Patent Document 1, for example.

  In order to control a wide flow rate range, the piezoelectric actuator needs a large amount of displacement. In order to obtain a large amount of displacement, it is necessary to increase the length dimension that is the stacking direction of the piezoelectric actuators. For this reason, there is a problem that equipment such as a flow rate control valve in which the piezoelectric actuator is incorporated, and a mass flow controller using the flow rate control valve become large, and a large displacement amount and miniaturization are desired for the piezoelectric actuator.

  For example, Patent Document 2 has been proposed as a method for reducing the length of a piezoelectric actuator and obtaining a large displacement. FIG. 5 is a perspective view of an actuator using a conventional displacement enlarging mechanism. In the actuator using the conventional displacement enlarging mechanism disclosed in Patent Document 2, two electrostrictive elements 101 and 102 are arranged in parallel, and the displacement of one electrostrictive element 102 is transferred to the other via a coupling mechanism 104. Is transmitted to the electrostrictive element 101, and the displacement is added and output. In the lever-based displacement magnifying mechanism, the fixed end member 103 is formed in a box shape that is integral with the hinge portion, which is the lever of the lever, and surrounds the electrostrictive elements 101 and 102, whereby the generated displacement of the electrostrictive elements 101 and 102 is reduced. It is possible to transmit to the point of action.

Japanese Patent Laid-Open No. 11-22845 JP-A-1-192182

  In the configuration described in Patent Document 2, since the fixed end member for fixing the piezoelectric element (electrostrictive element) has a box shape surrounding the piezoelectric element, it is difficult to further reduce the size. Further, although the purpose is to obtain rigidity by making the fixed end member into a box shape, in order to obtain rigidity, a certain thickness is required, which is a factor that hinders downsizing. Furthermore, since the piezoelectric element is simply connected to the coupling mechanism of the fixed end member by bonding or the like, when the piezoelectric element is displaced, an inclination or a gap is generated in the connecting portion of the piezoelectric element and the coupling mechanism, and the piezoelectric element There is a problem that it is difficult to transmit the displacement without waste, or the piezoelectric element is subjected to stress in the rotation or bending direction and reliability cannot be obtained.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to provide a displacement enlarging device that realizes downsizing and expands the displacement of a piezoelectric actuator and transmits it without waste, and the displacement enlarging device A flow control valve is provided.

  According to the present invention, a displacement transmission member coupled to the displacement output member via the first coupling sphere, and a first piezoelectric actuator coupled to the fixed base via the second coupling sphere are provided, and the displacement A support column is arranged between the transmission member and the first piezoelectric actuator, one end of the support column is fixed to a fixed base, and the other end of the support column is connected to the other end of the support column via a hinge portion. An arm extending in two directions perpendicular to the vertical direction of the support column and opposite to each other; one end of the displacement transmitting member on one side of the arm and one end of the first piezoelectric actuator on the other side of the arm; Are connected via a third connecting sphere, respectively, to obtain a displacement enlarging device.

  According to the present invention, there is provided the displacement magnifying device described above, wherein the displacement transmitting member is a second piezoelectric actuator.

  According to the present invention, there is provided the displacement enlarging device described above, wherein the displacement transmitting member is a metal rod.

  According to the present invention, the hinge portion is characterized in that a groove is formed on at least one of the surfaces of the end portion of the column facing the displacement transmission member and the first piezoelectric actuator. Thus, the displacement magnifying device is obtained.

  Also, according to the present invention, the displacement enlarging device described above is characterized in that the depth of the groove is large on the displacement transmission member side.

  Further, according to the present invention, there is obtained a flow rate control valve characterized in that the displacement output member is a diaphragm structure, includes the displacement magnifying device, and opens and closes a fluid flow path by the operation of the diaphragm structure. .

  According to the present invention, it is possible to provide a displacement enlarging device that realizes miniaturization, expands the displacement of the piezoelectric actuator and transmits it without waste, and a flow rate control valve equipped with the displacement enlarging device.

The front view of the flow control valve provided with the displacement expansion apparatus which concerns on 1st embodiment. The front view when the piezoelectric actuator is displaced in the flow control valve according to the first embodiment. The front view of the flow control valve provided with the displacement expansion apparatus which concerns on 2nd embodiment. The front view of the flow control valve provided with the displacement expansion apparatus which concerns on 3rd embodiment. The perspective view of the actuator using the conventional displacement expansion mechanism.

  Embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a front view of a flow control valve provided with a displacement magnifying device according to a first embodiment. The displacement magnifying device 100 of the first embodiment includes a displacement transmission member that is connected to a diaphragm structure 12 that is a displacement output member via a first connection ball 6, and a second connection ball 7 that is attached to the fixed base 11. A first piezoelectric actuator 1 is provided to be connected through the first piezoelectric actuator 1. In the first embodiment, the second piezoelectric actuator 2 is used as the displacement transmission member.

  In the second piezoelectric actuator 2 and the diaphragm structure 12, indentations with which the first connection sphere 6 is inscribed are respectively formed in portions that contact the first connection sphere 6. Similarly, in the portions of the first piezoelectric actuator 1 and the fixed base 11 that are in contact with the second connecting sphere 7, recesses that are inscribed by the second connecting sphere 7 are formed. This dent should just be the shape which the 1st connection ball | bowl 6 and the 2nd connection ball | bowl 7 can rotate freely, and a cone shape and the shape whose cross section becomes a semicircle or V shape are preferable.

  The first piezoelectric actuator 1 and the second piezoelectric actuator 2 are arranged side by side in the displacement direction, that is, the length direction. Between the first piezoelectric actuator 1 and the second piezoelectric actuator 2, a support column 3 is arranged so that one end of the support column 3 is fixed to a fixed base 11. The fixed base 11 and the column 3 may be integrally formed of the same member. A hinge portion 4 is formed at the other end of the column 3. Further, an arm 5 extending in two directions opposite to each other at right angles to the standing direction of the column 3 from the tip of the column 3 is provided via the hinge portion 4. One end of the first piezoelectric actuator 1 and the second piezoelectric actuator 2 is connected to the arm 5 via third connection balls 8a and 8b, respectively. The support 3 and the arm 5 may be integrally formed of the same member, and the material is preferably a metal material having a low coefficient of thermal expansion because the piezoelectric actuator exhibits negative thermal expansion. For example, an iron nickel alloy is used.

  The arm 5 includes adjusting screws 9 a and 9 b and lock nuts 10 a and 10 b for connecting to the first piezoelectric actuator 1 and the second actuator 2. One end in the height direction of the first piezoelectric actuator 1 and the second piezoelectric actuator 2 is in contact with the adjusting screws 9a and 9b of the arm 5 through third connecting balls 8a and 8b, respectively. In the first piezoelectric actuator 1 and the second piezoelectric actuator 2 and the adjusting screws 9a and 9b, the third contact balls 8a and 8b are in contact with the third connection balls 8a and 8b. Has been. This dent may be any shape that allows the third connecting spheres 8a and 8b to freely rotate, and is preferably a conical shape with a semicircular or V-shaped cross section. The first piezoelectric actuator 1 and the second piezoelectric actuator 2 are aligned with the fixed base 11 and the diaphragm structure 12 with the adjusting screws 9a and 9b, and are fixed to the arm 5 with the lock nuts 10a and 10b.

  The hinge portion 4 is formed with a groove on at least one of the surfaces of the upper end portion of the support column 3 facing the second piezoelectric actuator 2 and the first piezoelectric actuator 1, and the first piezoelectric actuator 1 is displaced. Work as a fulcrum of time. The hinge unit 4 only needs to convert linear motion, which is a slight displacement of the first piezoelectric actuator 1, into rotational motion and transmit it to the second piezoelectric actuator 2, and its configuration is not limited to the groove. As in the present invention, the hinge portion 4 that forms a groove in the end portion of the column 3 to partially reduce the rigidity is preferable because of its simple configuration.

  The hinge portion 4 is a portion where bending stress is repeatedly applied by the operation of the first piezoelectric actuator 1. Therefore, it is necessary to design the bending stress so that it does not exceed the yield point of the material forming the column 3 and to take into account long-term use and to ensure sufficient reliability. On the other hand, when the rigidity of the hinge part 4 is too large, the operation of the arm 5 due to the displacement of the first piezoelectric actuator 1 is hindered, and there is a possibility that loss of transmission of the displacement occurs. In the hinge part 4 of the present invention, reliability and suppression of displacement transmission loss are ensured by optimally designing the size of the hinge part 4 with respect to the column 3. Specifically, the size of the hinge portion 4 is preferably about 5 to 25% in length (displacement direction) and about 5 to 20% in width with respect to the dimensions of the column 3. Further, a groove may be formed also in the depth (thickness direction) of the support column, and in that case, the size is preferably 40% or less of the depth of the support column.

  The first piezoelectric actuator 1 and the second piezoelectric actuator 2 use a metal case-enclosed piezoelectric actuator in which a piezoelectric element is housed in a metal case, and a dry nitrogen gas is sealed inside the metal case. desirable. The piezoelectric element has a structure in which about 100 to 1000 layers of piezoelectric ceramic layers having a thickness of about 100 μm and internal electrode layers of about 1 to 2 μm are alternately stacked. Since the adhesion strength between the piezoelectric ceramic layer and the internal electrode layer is low, peeling or cracking may occur at the interface between the piezoelectric ceramic layer and the internal electrode layer when bending stress is applied to the piezoelectric element. Therefore, when the first piezoelectric actuator 1 and the second piezoelectric actuator 2 are fixed, it is desirable that the bending stress is not applied.

  In the present invention, as described above, the first piezoelectric actuator 1 is connected to the fixing base 11 and the adjusting screw 9a of the arm 5 via the second connecting ball 7 and the third connecting ball 8a. With this configuration, when the first piezoelectric actuator 1 is connected and fixed to the fixed base 11 and the arm 5, the first piezoelectric actuator 1 and the fixed base 11 do not have to be adjusted precisely without first adjusting the positional accuracy. It is possible to prevent bending stress from being applied to the piezoelectric actuator 1. Further, when the first piezoelectric actuator 1 is displaced, there is no gap between the first piezoelectric actuator 1 and the adjusting screw 9a of the arm 5, and the displacement of the first piezoelectric actuator 1 is not wasted. Transmission to the arm 5 is possible.

  The second piezoelectric actuator 2 is connected to the diaphragm structure 12 and the adjusting screw 9b of the arm 5 via the first connecting sphere 6 and the third connecting sphere 8b. With this configuration, when the second piezoelectric actuator 2 is connected and fixed to the diaphragm structure 12 and the arm 5, the positional accuracy of the second piezoelectric actuator 2 and the diaphragm structure 12 does not need to be strictly adjusted. It is possible to prevent bending stress from being applied to the second piezoelectric actuator 2. Further, when the first piezoelectric actuator 1 is displaced and transmitted to the arm 5 and the second piezoelectric actuator 2, there is no gap between the second piezoelectric actuator 2 and the adjusting screw 9b of the arm 5. The displacement of the first piezoelectric actuator 1 can be transmitted to the arm 5 and the second piezoelectric actuator 2 without waste.

  FIG. 2 is a front view of the flow rate control valve according to the first embodiment when the piezoelectric actuator is displaced. In FIG. 2, the fluid control valve portion is a cross-sectional view for ease of explanation.

  When a voltage is applied to the first piezoelectric actuator 1 connected to the fixed base 11, the first piezoelectric actuator 1 is displaced in the direction of arrow A, and the position of the arm 5 on the side connected to the first piezoelectric actuator 1 is raised. The arm 5 is tilted. Accordingly, the position of the arm 5 on the side connected to the second piezoelectric actuator 2 is lowered, and the displacement is transmitted to the second piezoelectric actuator 2. When a voltage is further applied to the second piezoelectric actuator 2, the second piezoelectric actuator 2 is displaced in the direction of arrow B. That is, the displacement of the first piezoelectric actuator 1 and the displacement of the second piezoelectric actuator 2 are superimposed, and the displacement can be transmitted to the diaphragm structure 12.

  An inclination correction mechanism 13 is disposed on at least a part of the outer peripheral portion of the diaphragm structure 12, and the diaphragm structure 12 is fitted therein. With this configuration, it is possible to correct the displacement in the rotational direction of the displacement transmitted to the second piezoelectric actuator 2 in the linear direction.

  Next, the behavior of the flow control valve provided with the diaphragm structure 12 will be described.

  The flow control valve of the first embodiment includes a diaphragm structure 12 that transmits and outputs a displacement from the displacement magnifying device 100 described above, an inclination correction mechanism 13, a flow path 14 formed in the fixed base 11, and a valve body 15. Consists of A flow path 14 is formed in the fixed base 11, and a valve body 15 is provided on the surface of the fixed base 11 so that a part of the flow path 14 opens. The diaphragm structure 12 has a pressurizing part 16 and a fixing part 17 and is disposed so as to face the valve body 15.

  By applying a displacement, that is, a driving force from the displacement enlarging device 100 to the pressurizing portion 16 of the diaphragm structure 12, the fixing portion 17 is pressed against the valve body 15, the interval between the flow paths 14 is adjusted, and the flow rate is controlled. . When no voltage is applied to the piezoelectric actuator, the interval between the fixed portion 17 and the valve body 15 is maximized, and the flow rate is also maximized.

(Second embodiment)
FIG. 3 is a front view of a flow control valve provided with the displacement magnifying device according to the second embodiment. In the second embodiment, the position where the groove is formed in the hinge portion is different from that in the first embodiment, and other configurations are the same as those in the first embodiment, so only the configuration of the hinge portion will be described. .

  In the displacement magnifying apparatus 200 according to the second embodiment, the groove is formed in the hinge portion 24 so that the depth of the groove is larger on the second piezoelectric actuator 2 side that is a displacement transmission member. With this configuration, the position of the fulcrum can be adjusted so that the displacement transmitted to the second piezoelectric actuator 2 increases. The hinge portion 24 is a fulcrum, the connecting portion between the first piezoelectric actuator 1 and the arm 25 is a force point, the connecting portion between the second piezoelectric actuator 2 and the arm 25 is an action point, the distance C between the fulcrum and the force point, When the ratio of the distance D of the action points is 1: 2 to 3, the displacement of the first piezoelectric actuator 1 is enlarged, and the flow rate control of 1.5 to 2 times becomes possible.

(Third embodiment)
FIG. 4 is a front view of a flow control valve provided with the displacement magnifying device according to the third embodiment. In 3rd Embodiment, the structure except having used the metal rod as a displacement transmission mechanism is the same as 2nd Embodiment.

  In the displacement magnifying apparatus 300 according to the third embodiment, the metal rod 32 is used as the displacement transmission mechanism. Similarly to the second embodiment, when the depth of the groove of the hinge portion 34 is adjusted and the displacement can be enlarged, the displacement of the first piezoelectric actuator 1 can be changed even if the displacement transmitting member is a metal rod 32. Can be enlarged and output. Unlike the first embodiment and the second embodiment, the displacement of the second actuator is not superimposed, but this configuration can reduce the number of piezoelectric actuators used by half, thereby reducing the cost. Is possible.

  As described above, the displacement magnifying device of the present invention does not require the use of a box-shaped fixed end member with high rigidity as in the prior art, and can be miniaturized. In addition, since a metal case-enclosed piezoelectric actuator is used, there is no need for sealing with a box-shaped fixed end member or the like, and the structure is simple and manufacture is easy.

  In other words, according to the present invention, it is possible to provide a displacement enlarging device that realizes miniaturization, expands the displacement of the piezoelectric actuator and transmits it without waste, and a flow control valve equipped with the displacement enlarging device.

DESCRIPTION OF SYMBOLS 1 1st piezoelectric actuator 2 2nd piezoelectric actuator 3 Support | pillar 4, 24, 34 Hinge part 5, 25 Arm 6 1st connection ball | bowl 7 2nd connection ball | bowl 8a, 8b 3rd connection ball | bowl 9a, 9b Adjustment screw 10a, 10b Lock nut 11, 111 Fixed base 12, 112 Diaphragm structure 13 Inclination correction mechanism 14, 114 Flow path 15, 115 Valve body 16, 116 Pressurization unit 17, 117 Fixed unit 32 Metal rod 100, 200, 300 Displacement Enlargement devices 101 and 102 Electrostrictive element 103 Fixed end member 104 Coupling mechanism

Claims (6)

  A displacement transmission member coupled to the displacement output member via the first coupling sphere; and a first piezoelectric actuator coupled to the fixed base via the second coupling sphere, the displacement transmission member and the first Struts are arranged so as to be lined up between the piezoelectric actuators, and one end of the strut is fixed to a fixed base. And an arm extending in two directions perpendicular to each other, one end of the displacement transmitting member being connected to one of the arms, and one end of the first piezoelectric actuator being connected to the other of the arms. A displacement magnifying device characterized by being connected via a sphere.   The displacement magnifying device according to claim 1, wherein the displacement transmitting member is a second piezoelectric actuator.   The displacement magnifying device according to claim 1, wherein the displacement transmission member is a metal rod.   The said hinge part forms a groove | channel in at least one of the surface facing the said displacement transmission member and said 1st piezoelectric actuator of the edge part of the said support | pillar, The Claims 1-3 characterized by the above-mentioned. Displacement enlargement device.   The displacement magnifying device according to claim 1, wherein the depth of the groove is large on the displacement transmission member side.   The flow rate control valve, wherein the displacement output member is a diaphragm structure, includes the displacement enlarging device according to claim 1, and opens and closes a fluid flow path by an operation of the diaphragm structure.

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