Fluid control valve and fluid control device

Abstract

The present invention improves the durability of a displacement changing mechanism that changes the displacement of an actuator and transmits this displacement to a valve body, while reducing the number of components to achieve a compact configuration. A displacement changing mechanism 6 for changing the displacement of an actuator 4 and transmitting this displacement to a valve body 3 side is provided with: a cylindrical holding member 61 interposed between the valve body 3 and the actuator 4; a plurality of movable members 62 forming a partial columnar shape corresponding to the inner peripheral surface of the holding member 61; and a plurality of rotation support shafts 63 for rotatably supporting the plurality of movable members 62 with respect to the holding member 61. Each of the plurality of movable members 62 has an input part 62a displaced by receiving the driving force from the actuator 4, and an output part 62b for changing the displacement applied to the input part 62a and transmitting this displacement to the valve body 3 side.

Description

Fluid control valve and fluid control device

[0001] The present invention relates to a fluid control valve and a fluid control device.

[0002] As a conventional fluid control valve, as disclosed in Patent Documents 1 and 2, there has been considered a valve in which the displacement of an actuator is magnified and transmitted to a valve element.

[0003] The fluid control valve of Patent Document 1 has a configuration in which a driving force transmission member is provided between the valve element and the valve element drive unit. This driving force transmission member has a tongue portion formed by bending the upper part of a cylindrical body inward. The tongue portion has a protrusion formed on the upper surface near the bent portion. When the protrusion receives driving force from the valve element drive unit, the tongue portion acts as a lever with the bent portion as a fulcrum, and the free end portion of the tongue portion is displaced downward to transmit the driving force to the valve element.

[0004] However, with the configuration of Patent Document 1, there is a risk that the bent portion of the tongue portion may break due to metal fatigue, etc., as the valve disc is repeatedly opened and closed. Furthermore, to prevent breakage due to metal fatigue, the bent portion needs to have sufficient mechanical strength, but this requires that the driving force of the valve disc drive unit be increased, which may result in an increase in the size of the valve disc drive unit.

[0005] The fluid control valve of Patent Document 2 is configured to have a displacement amplification mechanism (displacement amplification means) that amplifies the displacement of the piezoelectric actuator and outputs it to the valve head. This displacement amplification mechanism includes a displacement transmission part (rotating part) connected to a support part via a fulcrum part, an input part disposed between the support parts and connected to the displacement transmission part via an input point part, and an output part connected to the displacement transmission part via an output point part. The support part, input part, displacement transmission part, and output part, as well as the fulcrum part, input point part, and output point part, are formed integrally or separately from a metal material, a resin material, or the like.

[0006] However, in the configuration of Patent Document 2, if the various parts of the displacement amplification mechanism are formed as a single unit, there is a risk that the bent part of the tongue part may break due to metal fatigue or the like as the valve body is repeatedly opened and closed, just as in the above-mentioned Patent Document 1. Furthermore, if the various parts of the displacement amplification mechanism are formed as separate bodies, the number of parts increases, making the structure more complicated.

[0007] JP 62-13884 A JP 2001-141091 A

[0008] Therefore, the present invention has been made to solve the above-mentioned problems, and its objective is to improve the durability of the displacement change mechanism that changes the displacement of the actuator and transmits it to the valve body side, as well as to reduce the number of parts to create a compact configuration.

[0009] That is, the fluid control valve according to the present invention comprises an actuator for driving a valve body, and a displacement change mechanism for changing the displacement of the actuator and transmitting it to the valve body side, wherein the displacement change mechanism comprises a cylindrical holding member interposed between the valve body and the actuator, a plurality of movable members each having a partially cylindrical shape that is disposed inside the holding member and corresponds to the inner circumferential surface of the holding member, and a plurality of rotary support shafts that penetrate each of the movable members and rotatably support the movable members relative to the holding member, and wherein each of the movable members has an input section that is displaced by receiving a driving force from the actuator, and an output section that changes the displacement applied to the input section and transmits it to the valve body side.

[0010] In such a fluid control valve, the displacement change mechanism is configured such that multiple movable members having input and output portions are rotatably supported by multiple rotary support shafts inside a cylindrical holding member, thereby reducing the number of parts and achieving a compact configuration. Furthermore, because each of the multiple movable members is rotatably supported by a rotary support shaft and the amount of rotation of the movable members is small, wear due to rotation of the movable members is reduced, thereby improving durability. Furthermore, because the multiple movable members form a partial cylindrical shape corresponding to the inner circumferential surface of the holding member, the work of assembling the multiple movable members to the inner circumferential surface of the holding member is simplified.

[0011] In order to minimize the number of parts in the displacement change mechanism and to reduce the number of wear points, it is desirable that the plurality of movable members include two movable members, and that the two movable members are rotatably supported by two rotary support shafts that are provided at symmetrical positions on the holding member with respect to the central axis, and that the two movable members have a shape that has a partially arcuate outer surface that corresponds to the inner circumferential surface of the holding member and opposing surfaces that face each other on the two movable members.

[0012] In order to facilitate assembly of the plurality of movable members and the rotary support shaft to the holding member, it is desirable that the rotary support shaft be inserted into and fixed to two fixing holes formed in two opposing side wall portions of the holding member, at least one of the two fixing holes being a through hole. With this configuration, the displacement change mechanism can be assembled by inserting the rotary support shaft through the through hole formed in the side wall portion of the holding member with the movable members disposed inside the holding member, thereby facilitating assembly.

[0013] As a specific embodiment of the fixing holes formed in the holding member and the rotation support shaft, it is desirable that the rotation support shaft has a clearance with one of the two fixing holes and is fitted into the other of the two fixing holes. With this configuration, the rotation support shaft can be fixed to the holding member by inserting it from one fixing hole to the other fixing hole formed in the side wall of the holding member.

[0014] It is desirable that the movable member be supported inside the holding member so as to be slidable in the axial direction of the rotation support shaft when supported by the rotation support shaft. With this configuration, the movable member, which has a partially cylindrical shape corresponding to the inner peripheral surface of the holding member, comes into contact with the inner peripheral surface of the holding member when rotating around the rotation support shaft, and the movable member moves toward the central axis of the holding member. In other words, the movable member being supported so as to be slidable in the axial direction of the rotation support shaft provides a so-called self-aligning function.

[0015] A specific embodiment of the input section and the output section is that the input section and the output section are provided on the actuator side of the movable member and are arranged so as to sandwich the rotation support shaft that supports the movable member, and the output section inverts the displacement applied to the input section and transmits it to the valve body side.

[0016] As a specific embodiment for inverting the displacement of the actuator and outputting it to the valve body side, the fluid control valve is connected to or in contact with the valve body, and further includes a shaft portion that passes through the inside of the holding member and extends toward the actuator, the plurality of movable members are arranged inside the holding member so as to surround the shaft portion, the input portion is provided outside the rotation support shaft in the plurality of movable members, and the output portion is provided inside the rotation support shaft, and the output portion inverts the displacement applied to the input portion and transmits it to the shaft portion.

[0017] In order to suitably return the valve element displaced by the displacement change mechanism to its initial position before displacement, it is conceivable to provide an elastic body that biases the valve element in the direction opposite to the displacement direction caused by the output portion.

[0018] In order to transmit the driving force of the actuator to multiple movable members at once and simplify the configuration of the fluid control valve, it is desirable that the fluid control valve further include a transmission member interposed between the actuator and the multiple movable members, which transmits the driving force of the actuator to the input portion of each of the multiple movable members.

[0019] Furthermore, the fluid control device according to the present invention is characterized by comprising the above-mentioned fluid control valve, a fluid sensor provided upstream or downstream of the fluid control valve, and a valve control unit that controls the fluid control valve based on the output of the fluid sensor.

[0020] As described above, according to the present invention, the durability of the displacement change mechanism that changes the displacement of the actuator and transmits it to the valve body side can be improved, and the number of parts can be reduced to achieve a compact configuration.

[0021] 1 is a diagram schematically illustrating the configuration of a fluid control device according to one embodiment of the present invention; FIG. 2 is an enlarged cross-sectional view of a fluid control valve (valve closed state) of the same embodiment; FIG. 3 is an enlarged cross-sectional view of a fluid control valve (valve open state) of the same embodiment; (a) an enlarged cross-sectional view of a displacement change mechanism of the same embodiment, and (b) an enlarged cross-sectional view of an open state; FIG. 4 is a plan view of the displacement change mechanism of the same embodiment; FIG. 5 is an exploded perspective view of the displacement change mechanism of the same embodiment; and FIG. 6 is a diagram schematically illustrating the configuration of a fluid control device of a modified embodiment.

[0022] An embodiment of a fluid control device using a fluid control valve according to the present invention will be described below with reference to the drawings. Note that, for ease of understanding, all of the drawings shown below are drawn in a schematic manner with appropriate omissions or exaggerations. Identical components are given the same reference numerals, and their descriptions will be omitted where appropriate.

[0023] 1. Basic Configuration of the Fluid Control Device 100 The fluid control device 100 according to this embodiment is a so-called mass flow controller used in a semiconductor manufacturing process. Note that the fluid control device 100 can be used not only in the semiconductor manufacturing process but also in other processes.

[0024] The fluid control device 100 here is a pressure type, as shown in Fig. 1. Specifically, the fluid control device 100 includes a flow path block B having a flow path R therein, a fluid control valve V installed in the flow path block B, a pair of pressure sensors PS1 and PS2 that are fluid sensors installed upstream or downstream of the fluid control valve V in the flow path block B, and a valve controller CTL that feedback controls the fluid control valve V so that the flow rate value of the flow path R, calculated based on the pressure values ​​measured by the pair of pressure sensors PS1 and PS2, approaches a predetermined target value.

[0025] The flow path block B has, for example, a rectangular parallelepiped shape, and has a fluid control valve V and a pair of pressure sensors PS1, PS2 installed on a predetermined surface thereof. The flow path block B also has a recessed accommodation portion B1 on a predetermined surface thereof for installing the fluid control valve V. The accommodation portion B1 divides the flow path R into an upstream flow path R1 and a downstream flow path R2. One end of the upstream flow path R1 opens on the bottom surface of the accommodation portion B1, and one end of the downstream flow path R2 opens on a side surface thereof.

[0026] The pair of pressure sensors PS1 and PS2 are connected to the upstream and downstream sides, respectively, of a fluid resistance S1 such as a laminar flow element provided in the flow path R, and both are connected to a flow rate calculation unit S2 that calculates the flow rate based on the outputs of the pair of pressure sensors PS1 and PS2. The pair of pressure sensors PS1 and PS2 are attached in a row together with the fluid control valve V on a predetermined surface of the flow path block B.

[0027] The valve control unit CTL has a so-called computer equipped with a CPU, memory, A / D and D / A converters, etc., and executes programs stored in the memory to realize various functions by various devices working together. Specifically, it feedback-controls the valve opening of the fluid control valve V so that the flow rate value calculated by the flow rate calculation unit S2 approaches a target value stored in advance in memory.

[0028] 2. Specific Configuration of the Fluid Control Valve V Next, a description will be given of the fluid control valve V of this embodiment. For convenience of explanation, the valve seat member 2 side with respect to the valve element 3 will be referred to as the lower side, and the actuator 4 side with respect to the valve element 3 will be referred to as the upper side.

[0029] The fluid control valve V of this embodiment is, for example, a normally closed type, and as shown in FIGS. 1 and 2 , includes a valve seat member 2 on which a valve seat 21 is formed, a valve element 3 that is provided so as to be able to move toward and away from the valve seat 21, and an actuator 4 for driving the valve element 3.

[0030] The valve seat member 2 has a valve seat 21 for separating the upstream flow path R1 and the downstream flow path R2, and is accommodated in the accommodation portion B1 of the flow path block B. The valve seat member 2 of this embodiment has an annular valve seat 21. A first internal flow path 2a communicating with the upstream flow path R1 is formed inside the valve seat 21. Furthermore, a second internal flow path 2b communicating with the downstream flow path R2 is formed outside the valve seat 21.

[0031] The valve element 3 has a seating surface 31 that seats on the valve seat 21 of the valve seat member 2. As shown in Figures 2 and 3, the valve element 3 of this embodiment is provided in contact with the lower end of a shaft portion 51 that extends in the direction of advancement and retreat by the actuator 4. This shaft portion 51 is supported by a disk-shaped diaphragm portion 52. The outer periphery of the diaphragm portion 52 is connected to a cylindrical support portion 53. The valve element 3 is provided below the diaphragm portion 52 inside the support portion 53. This support portion 53 is fixed to the flow path block B via a sealing member (not shown). In this embodiment, the shaft portion 51, diaphragm portion 52, and support portion 53 are integrally formed.

[0032] The actuator 4 is, for example, a piezoelectric actuator, and has one or more piezo stacks in which piezoelectric ceramic layers and electrode layers are alternately stacked. The actuator 4 is housed in a casing 40, and an upper end of the actuator 4 (the end opposite the valve body 3) is fixed to the casing 40. In other words, as the actuator 4 expands and contracts, the lower end of the actuator 4 (the end on the valve body 3 side) is displaced. As the lower end of the actuator 4 is displaced, the valve body 3 moves via a displacement change mechanism 6, which will be described later.

[0033] With the above configuration, before the actuator 4 extends, the seating surface 31 of the valve disc 3 abuts against the valve seat 21 of the valve seat member 2, blocking the upstream flow path R1 and the downstream flow path R2. As the actuator 4 extends, the seating surface 31 of the valve disc 3 moves away from the valve seat 21 of the valve seat member 2, connecting the upstream flow path R1 and the downstream flow path R2. The position of the valve disc 3 changes depending on the amount of extension of the actuator 4, and as a result, the distance between the valve seat 21 and the seating surface 31 changes, controlling the flow rate.

[0034] 1, the fluid control valve V of this embodiment is provided with a displacement changing mechanism 6 that changes (in this case, enlarges) the displacement of the actuator 4 and transmits it to the valve element 3. The displacement changing mechanism 6 of this embodiment is configured to invert the displacement input to the actuator 4 and transmit it to the valve element 3.

[0035] Specifically, as shown in Figures 2 to 6, the displacement change mechanism 6 includes a cylindrical holding member 61, a plurality of movable members 62 arranged inside the holding member 61, and a plurality of rotary support shafts 63 that rotatably support the plurality of movable members 62 relative to the holding member 61.

[0036] The holding member 61 is provided between the valve body 3 and the actuator 4. Specifically, as shown in FIGS. 2 and 3 , the holding member 61 is provided above the diaphragm portion 52 inside the support portion 53 or the containing block 7 connected to the support portion 53. In this embodiment, the shaft portion 51 is disposed at the center inside the holding member 61. That is, the shaft portion 51 communicates with the inside of the holding member 61 and extends toward the actuator 4. The holding member 61 is fixed inside the support portion 53 and the containing block 7 by a fixing block 8 that is screwed and fixed to the containing block 7. The actuator 4 is fixed to the upper end of the fixing block 8 (the end opposite the valve body 3) (see FIG. 1 ).

[0037] As shown in particular in FIGS. 5 and 6 , the multiple movable members 62 have a partially cylindrical shape corresponding to the inner circumferential surface of the cylindrical holding member 61. In this embodiment, two movable members 62 are provided. These two movable members 62 have a partially arcuate outer surface corresponding to the inner circumferential surface of the holding member 61 and opposing surfaces that face each other. That is, each movable member 62 has a semi-cylindrical shape corresponding to the inner circumferential surface of the holding member 61. The two movable members 62 have the same shape. The two movable members 62 are disposed inside the holding member 61 so that their partially cylindrical surfaces face the inner circumferential surface of the holding member 61. These two movable members 62 are disposed around the central axis of the valve body 3 and are disposed inside the holding member 61 so as to surround the shaft portion 51. A housing recess 62m that houses the shaft portion 51 is formed along the central axis C on the radially inner side of the two movable members 62 (see FIGS. 4 and 5 ).

[0038] Each movable member 62 also has an input portion 62a that is displaced upon receiving a driving force from the actuator 4 (displacement of the actuator 4), and an output portion 62b that modifies the displacement applied to the input portion 62a and transmits it to the valve body 3. In this embodiment, the input portion 62a is provided on the upper surface of each movable member 62, on the opposite side (outside) of the shaft portion 51 with respect to the rotation support shaft 63. Also, the output portion 62b is provided on the upper surface of each movable member 62, on the shaft portion 51 side (inside) of the rotation support shaft 63. These input portion 62a and output portion 62b are formed as convex portions on the upper surface of the movable member 62. By providing both the input portion 62a and the output portion 62b on the upper surface of the movable member 62 in this manner, the output portion 62b inverts the displacement applied to the input portion 62a and transmits it to the shaft portion 51. In this embodiment, as shown in FIGS. 2 and 3 , a displacement receiving portion 511 that comes into contact with the output portion 62b and receives the displacement is provided at the upper end of the shaft portion 51.

[0039] 2 and 3 , the driving force of the actuator 4 is transmitted to the input portions 62a of the two movable members 62 by a transmission member 64. This transmission member 64 is provided between the actuator 4 and the plurality of movable members 62. Specifically, the transmission member 64 has a connecting shaft 64a whose upper end is connected to the actuator 4, and a cylindrical transmission input portion 64b, for example, that is provided at the lower end of the connecting shaft 64a and transmits the driving force to the input portions 62a of the two movable members 62.

[0040] The upper end of the shaft portion 51 and the displacement receiving portion 511 provided thereon are disposed inside (inside) this transmission input portion 64b. In addition, an elastic body 65 that urges the valve element 3 in the direction opposite to the displacement direction by the output portion 62b is provided between the displacement receiving portion 511 provided at the upper end of the shaft portion 51 and the transmission input portion 64b. This elastic body 65 urges the shaft portion 51 in the valve closing direction (downward) relative to the transmission member 64. As a result, the valve element 3 is urged in the valve closing direction. Note that a leaf spring, a spring spring, or the like can be used as the elastic body 65.

[0041] 4 and 5, the two movable members 62 are rotatably supported by two rotation support shafts 63 provided in symmetrical positions on the holding member 61 with respect to the central axis C. Specifically, the two rotation support shafts 63 are perpendicular to the central axis C of the holding member 61 and are provided in symmetrical positions with respect to the central axis C of the holding member 61.

[0042] These rotation support shafts 63 are provided so as to penetrate through each of the multiple movable members 62. For this reason, the movable members 62 are formed with through holes 62h into which the rotation support shafts 63 are inserted, as shown in FIGS. 4 to 6. Furthermore, as shown in FIGS. 5 and 6, each rotation support shaft 63 is inserted and fixed into two fixing holes 61h1, 61h2 formed in two opposing side wall portions of the holding member 61. Here, the two fixing holes 61h1, 61h2 are through holes, and the rotation support shaft 63 has a clearance with one of the two fixing holes 61h1, 61h2, and is fitted into the other fixing hole 61h2 of the two fixing holes 61h1, 61h2.

[0043] 5, the positional relationship between the input portion 62a and the output portion 62b of the movable member 62 and the rotation support shaft 63 is such that the input portion 62a is provided outside the rotation support shaft 63, and the output portion 62b is provided inside the rotation support shaft 63. As shown in FIGS. 4(a) and 5, the distance L2 between the output portion 62b and the rotation support shaft 63 is greater than the distance L1 between the input portion 62a and the rotation support shaft 63 (L1<L2). As a result, the amount of displacement of the actuator 4 input to the input portion 62a is magnified and output from the output portion 62b to the valve body 3 side.

[0044] 5 , when the movable member 62 is supported by the rotary support shaft 63, a clearance is provided between the movable member 62 and the inner peripheral surface of the holding member 61 so that the movable member 62 can rotate around the rotary support shaft 63 inside the holding member 61. When the movable member 62 is supported by the rotary support shaft 63 inside the holding member 61, the movable member 62 is supported so as to be slidable in the axial direction of the rotary support shaft 63. Therefore, although the movable member 62 is not positioned relative to the holding member 61, when the movable member 62 rotates around the rotary support shaft 63, the movable member 62 comes into contact with the inner peripheral surface of the holding member 61, and moves toward the central axis C of the holding member 61. In other words, when the movable member 62 is supported so as to be slidable in the axial direction of the rotary support shaft 63, a so-called self-aligning function is exhibited.

[0045] 4. Operation of the Fluid Control Valve V Next, the operation of the fluid control valve V according to this embodiment will be described.

[0046] When no voltage is applied to the actuator 4, the fluid control valve V is in a closed state in which the seating surface 31 of the valve body is seated on the valve seat 21 of the valve seat member 2 (see FIGS. 1 and 2).

[0047] Next, when a voltage is applied to the actuator 4, the actuator 4 expands. The driving force associated with this expansion of the actuator 4 is transmitted to the shaft portion 51 and the valve element 3 via the displacement change mechanism 6, and the valve element 3 moves in a direction away from the valve seat 21. As a result, the fluid control valve V changes from a closed state (see FIG. 2) to an open state (see FIG. 3). Note that the actuator 4 expands more as the applied voltage increases, so the valve opening can be controlled by adjusting the magnitude of the voltage.

[0048] Here, the displacement caused by the extension of the actuator 4 is amplified by a predetermined factor by the displacement change mechanism 6 and transmitted to the shaft portion 51 and the valve body 3 .

[0049] Specifically, when the actuator 4 extends, the driving force of the actuator 4 (displacement of the actuator 4) is input to the input portions 62a of the multiple movable members 62 via the transmission member 64. When the input portions 62a are displaced, the movable members 62 rotate around the rotation support shaft 63, and the output portions 62b are displaced. Here, the displacement of the output portions 62b is magnified by a predetermined factor relative to the displacement of the input portions 62a. The output portions 62b press the displacement receiving portions 511 of the shaft portion 51 upward, causing the shaft portion 51 and the valve element 3 to move in a direction away from the valve seat 21. As a result, the displacement of the actuator 4 is magnified and transmitted to the valve element 3.

[0050] 5. Effects of the Present Embodiment As described above, according to the fluid control device 100 of the present embodiment, the displacement change mechanism 6 is configured such that multiple movable members 62, each having an input portion 62 a and an output portion 62 b, are rotatably supported by multiple rotary support shafts 63 inside the cylindrical holding member 61, thereby reducing the number of parts and achieving a compact configuration. Furthermore, because each of the multiple movable members 62 is rotatably supported by the rotary support shaft 63 and the amount of rotation of the movable members 62 is small, wear due to rotation of the movable members 62 is reduced, thereby improving durability. Furthermore, because the multiple movable members 62 have a partial cylindrical shape corresponding to the inner circumferential surface of the holding member 61, the task of assembling the multiple movable members 62 to the inner circumferential surface of the holding member 61 can be easily performed.

[0051] 6. Other Embodiments For example, the displacement change mechanism may be configured to reduce the displacement of the actuator 4, in addition to increasing the displacement of the actuator 4. In this case, the distance between the output portion 62b and the rotation support shaft 63 is made smaller than the distance between the input portion 62a and the rotation support shaft 63. This reduces the displacement of the output portion 62b relative to the displacement of the input portion 62a, making it possible to accurately adjust the amount of movement of the valve disc 3. Furthermore, the driving force applied to the valve disc 3 can be increased.

[0052] Furthermore, the displacement change mechanism 6 may be configured to invert the displacement applied to the input portion 62a and transmit it to the valve element 3 side, or may be configured to transmit the displacement applied to the input portion 62a to the valve element 3 side without inverting it. In this case, it is conceivable to provide the input portion 62a on the upper surface of the movable member 62 and the output portion 62b on the lower surface of the movable member 62. In this configuration, it is conceivable to make the fluid control valve V a normally open type.

[0053] Furthermore, in order to reduce the number of parts and to facilitate assembly and simplify the structure, it is desirable to use two movable members 62, but the number of movable members 62 is not necessarily limited to two and may be three or more.

[0054] The two fixing holes 61h1, 61h2 to which the rotation support shaft 63 is fixed do not both need to be through holes, but it is sufficient that at least the fixing hole 61h1 having a clearance between it and the rotation support shaft 63 is a through hole. With this configuration, the rotation support shaft 63 can be fixed to the holding member 61 by inserting the rotation support shaft 63 through the fixing hole 61h1 having the clearance.

[0055] Furthermore, in the above embodiment, the valve body 3, the shaft portion 51, and the diaphragm portion 52 are configured as separate members, but they may be formed integrally.

[0056] Furthermore, in the above embodiment, the fluid control device 100 has been described as a differential pressure type, but it may also be a thermal type, as shown in Fig. 7. Specifically, this device comprises a capillary tube T connected in parallel to a flow path R so that a predetermined proportion of the fluid flowing through the flow path R is guided by fluid resistance S1, a heater H provided in the capillary tube T, and a pair of temperature sensors TS1 and TS2, which are fluid sensors, provided before and after the heater H. When a fluid flows through the capillary tube T, a temperature difference corresponding to the mass flow rate occurs between the two temperature sensors TS1 and TS2, and the flow rate is measured based on this temperature difference.

[0057] In the above embodiment, a piezoelectric element (piezo stack) is used as the actuator 4 of the fluid control valve V, but a solenoid or the like may also be used.

[0058] In addition, various modifications and combinations of the embodiments may be made as long as they do not go against the spirit of the present invention.

[0059] According to the present invention, it is possible to improve the durability of the displacement change mechanism that changes the displacement of the actuator and transmits it to the valve body side, and to reduce the number of parts to achieve a compact configuration.

[0060] DESCRIPTION OF SYMBOLS 100: Fluid control device V: Fluid control valve PS1, PS2: Pressure sensor (fluid sensor) CTL: Valve control section 3: Valve body C: Central axis 4: Actuator 51: Shaft section 6: Displacement change mechanism 61: Holding member 61h1, 61h2: Fixing hole 62: Movable member 62a: Input section 62b: Output section 63: Rotation support shaft 65: Elastic body 64: Transmission member

Claims

1. An actuator for driving the valve body, The system includes a displacement changing mechanism that changes the displacement of the actuator and transmits it to the valve body side, The displacement changing mechanism is A cylindrical retaining member is provided interposed between the valve body and the actuator, A plurality of movable members are arranged inside the holding member and are partially cylindrical in shape, corresponding to the inner circumferential surface of the holding member, Each of the aforementioned multiple movable members is provided through a plurality of rotational support shafts that rotatably support the plurality of movable members with respect to the holding member, Each of the aforementioned multiple movable members is An input section that is displaced by receiving a driving force from the actuator, A fluid control valve having an output unit that modifies the displacement applied to the input unit and transmits it to the valve body side.

2. The aforementioned plurality of movable members include two movable members, The two movable members are rotatably supported by the two rotational support shafts provided in the holding member at symmetrical positions with respect to the central axis. The fluid control valve according to claim 1, wherein the two movable members have a partially arc-shaped outer surface corresponding to the inner circumferential surface of the holding member and opposing surfaces that face each other between the two movable members.

3. The rotation support shaft is inserted into and fixed into two fixing holes formed in the two opposing side walls of the holding member. The fluid control valve according to claim 1, wherein at least one of the two fixing holes is a through hole.

4. The fluid control valve according to claim 3, wherein the rotating support shaft has a clearance with one of the two fixing holes and is fitted into the other of the two fixing holes.

5. The fluid control valve according to claim 1, wherein the movable member is supported within the holding member so as to be slidable in the axial direction of the rotating support shaft while being supported by the rotating support shaft.

6. The input unit and the output unit are provided on the actuator side of the movable member and are arranged so as to sandwich the rotation support shaft that supports the movable member. The fluid control valve according to claim 1, wherein the output unit reverses the displacement applied to the input unit and transmits it to the valve body side.

7. The valve body is connected to or in contact with the shaft portion which extends through the interior of the retaining member and toward the actuator side, The plurality of movable members are arranged inside the holding member so as to surround the shaft portion. In the plurality of movable members, the input section is provided outside the rotation support shaft, and the output section is provided inside the rotation support shaft. The fluid control valve according to claim 5, wherein the output unit reverses the displacement applied to the input unit and transmits it to the shaft unit.

8. The fluid control valve according to claim 1, further comprising an elastic body that biases the valve body in a direction opposite to the displacement direction of the output unit.

9. The fluid control valve according to claim 1, further comprising a transmission member interposed between the actuator and the plurality of movable members, which transmits the driving force of the actuator to the input portion of each of the plurality of movable members.

10. A fluid control valve according to any one of claims 1 to 9, A fluid sensor provided on the upstream or downstream side of the fluid control valve, A fluid control device comprising a valve control unit that controls the fluid control valve based on the output of the fluid sensor.