Fluid control valve and fluid control apparatus

Abstract

To reduce a magnetic resistance of a magnetic path including a valve body and thereby enable fluid control with lower current or voltage.SOLUTION: A fluid control valve includes: a passage block 2 formed with an internal passage 2R; an orifice 5 fixed to the passage block 2 and having a valve seat surface 5a; a valve body 6 having a seating surface 6a configured to be seated on the valve seat surface 5a and made of a magnetic material; and an actuator portion 7 that drives the valve body 6 by a magnetic force. The actuator portion 7 includes: an iron core 71 which is provided facing a surface 6b of the valve body 6 opposite to the seating surface 6a; a solenoid coil 72 wound around the iron core 71; and a casing 73 accommodating the iron core 71 and the solenoid coil 72 and made of a magnetic material. The casing 73 extends to a position surrounding a periphery of the valve body 6.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] Conventionally, as a fluid control valve, a proportional solenoid valve using a solenoid coil has been used, as shown in Patent Document 1. This proportional solenoid valve has a movable iron core having a valve body made of a magnetic material, and uses a fixed iron core and a coil wound around the fixed iron core as an actuator for driving the movable iron core. When electricity is applied to the coil, magnetic flux passes through the fixed iron core and the movable iron core, and the movable iron core is attracted to the fixed iron core, thereby adjusting the position of the valve body relative to the valve seat. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-145800 A Summary of the Invention [Problem to be solved by the invention]

[0004] When a fluid control valve is used in a supply line of a process gas in a semiconductor manufacturing device, it is desirable to reduce the contact area with the process gas as much as possible. For this reason, it is considered to accommodate an orifice having a valve seat inside a flow path block in which an internal flow path through which the process gas flows is formed. By accommodating the orifice in the flow path block, the length of the flow path through the valve seat can be shortened, and this is expected to reduce the contact area with the gas.

[0005] However, when the orifice is housed in the flow path block, the valve body facing the orifice and the actuator unit that drives the valve body are attached to the flow path block. In this case, the magnetic flux generated by the actuator unit cannot be efficiently passed through the valve body, and the magnetic performance is reduced. As a result, it becomes necessary to increase the current or voltage passed through the actuator unit to displace the valve body.

[0006] Therefore, the present invention has been made to solve the above-mentioned problems, and its main objective is to perform fluid control with less current or voltage by reducing the magnetic resistance of the magnetic path including the valve body. [Means for solving the problem]

[0007] That is, the fluid control valve of the present invention comprises a flow path block in which an internal flow path is formed, an orifice having a valve seat surface, a valve body made of a magnetic body having a seat surface that seats on the valve seat surface, and an actuator unit that drives the valve body by magnetic force, wherein the actuator unit has an iron core provided facing the surface opposite to the seat surface of the valve body, a solenoid coil wound around the iron core, and a casing made of a magnetic body that houses the iron core and the solenoid coil, and the casing extends to a position surrounding the periphery of the valve body.

[0008] According to such a fluid control valve, since an orifice having a valve seat surface is housed in a flow path block, the length of the flow path through the valve seat can be shortened, and it is expected that the gas contact area can be reduced. In this configuration, the casing made of a magnetic material that houses the iron core and the solenoid coil extends to a position surrounding the valve body made of a magnetic material, and a magnetic path is formed that guides the magnetic flux generated by the solenoid coil to the periphery of the valve body, so that the magnetic resistance of the magnetic path including the valve body can be reduced and the magnetic characteristics can be improved. As a result, it is possible to control the fluid with less current or voltage.

[0009] An example of a configuration in which the casing extends to a position surrounding the valve body is that the surface of the valve body opposite the seating surface is located closer to the iron core than the tip surface of the casing on the flow path block side.

[0010] Moreover, it is preferable that the fluid control valve according to the present invention further comprises a distance adjustment mechanism for adjusting the distance between the iron core and the valve body. By adjusting the distance between the iron core and the valve disc with this distance adjustment mechanism, it is possible to adjust (increase or decrease) the magnetic field (magnetic flux density) to the optimum level. This makes it possible to adjust the valve opening when fully open, for example. For example, by applying a constant voltage while flowing a fluid, it becomes possible to set the valve opening so that the fluid flows at the full scale (FS) that you want to adjust. Also, for example, if you want to control a minute flow rate, increasing the distance between the iron core and the valve disc weakens the magnetic force attracting the valve disc, making it possible to control the minute flow rate.

[0011] As a specific embodiment of the fluid control valve, it is considered that the fluid control valve further includes a mounting block attached to the flow path block and accommodating the valve body, and the iron core is fixed to the casing. With this configuration, the actuator unit can be removed together with the valve body by removing the mounting block from the flow passage block, facilitating disassembly and maintenance. Also, by mounting the casing to the mounting block, the iron core is provided facing the surface opposite to the seating surface of the valve body. In this configuration, as a specific embodiment of the distance adjustment mechanism, it is preferable that the distance adjustment mechanism is constituted by the casing and the mounting block.

[0012] A specific embodiment of the distance adjustment mechanism may include a male threaded portion formed on one of the outer peripheral surface of the casing or the mounting block, and a female threaded portion formed on the other of the outer peripheral surface of the casing or the mounting block, into which the male threaded portion screws. With this configuration, the distance between the iron core and the valve body can be adjusted by the simple operation of rotating the casing relative to the mounting block.

[0013] It is preferable that the mounting block is provided with a fixing portion that is movable forward and backward relative to the casing and that fixes the casing to the mounting block. With this configuration, the distance between the iron core and the valve body can be reliably maintained by adjusting the distance between the iron core and the valve body using the distance adjustment mechanism and then fixing the casing with the fixing portion.

[0014] As a specific embodiment for fixing the casing with the fixing part, it is desirable that the casing has a cylindrical end portion at the tip portion on the flow path block side, the mounting block has a slit to accommodate the cylindrical end portion, the fixing part is provided on a side wall portion that forms the slit in the mounting block, and the cylindrical end portion is fixed to the side wall portion that forms the slit in the mounting block by the fixing part.

[0015] The casing desirably has a thin portion located inside the mounting block, and a thick portion located outside the mounting block and having a wall thickness greater than that of the thin portion. Also, it desirably has a thin portion having the male thread portion or the female thread portion formed on an outer peripheral surface thereof, and a thick portion formed on the opposite side of the thin portion from the flow path block. With this configuration, the casing has a thick portion, which makes it difficult for magnetic lines of force to leak to the outside, and allows the magnetic lines of force to pass through the valve body efficiently, making it easier to pull up the valve body. Also, since the thick portion is located outside the mounting block, the outer diameter of the thin portion can be made small, eliminating the need to enlarge the mounting block. Also, since the thick portion is operated when rotating the casing relative to the mounting block, the rotation torque is reduced, making it easier to rotate the casing.

[0016] In order to accommodate the dimensional tolerances of each component and fix the solenoid coil, it is desirable that the iron core and the casing are arranged to be slidable relative to the solenoid coil, and that the relative position between the solenoid coil and the valve body does not change regardless of movement of the iron core and the casing by the distance adjustment mechanism.

[0017] In order to facilitate disassembly and assembly of the fluid control valve and facilitate maintenance, it is desirable for the flow path block to have an accommodating recess for accommodating the orifice.

[0018] In order to facilitate assembly of the fluid control valve, it is preferable that the mounting block is attached to the flow passage block to fix the orifice accommodated in the accommodation recess.

[0019] When a thick wire is used for a solenoid coil, the resistance value decreases and the current value increases. As a result, the magnetic force increases, but the coil is more likely to generate heat. On the other hand, when a thin wire is used for a solenoid coil, the resistance value increases and the current value decreases. As a result, the magnetic force decreases, but the coil is less likely to generate heat. In order to combine these properties to achieve a configuration that is high in magnetic force while not easily generating heat, it is desirable for the solenoid coil to be constructed using a plurality of wires having different wire diameters.

[0020] As a specific configuration using multiple wires having different wire diameters, it is desirable that the solenoid coil is divided into multiple coil elements along the axial direction of the iron core, and that the wires of the multiple coil elements have different wire diameters. For example, if the wire diameter is made smaller along the axial direction of the core toward the valve body side, heat generation in the coil on the valve body side can be suppressed, and the temperature effect of the heat generated by the coil on the fluid, peripheral equipment, etc. Also, when a thermal flow sensor is used together with the fluid control valve, the temperature effect of the heat generated by the coil on the thermal flow sensor can be reduced. In addition, if the wire diameter is increased toward the valve body along the axial direction of the core, the heat generated by the coil on the valve body side can be increased, and the fluid flowing through the fluid control valve can be heated. For example, if the fluid flowing through the fluid control valve is a gas with a low vapor pressure, the heat generated by the coil can prevent the gas from liquefying, and corrosion of the valve body, etc. caused by liquefaction can be prevented.

[0021] The solenoid coil is preferably an air-core coil (also called a bobbinless coil). With this configuration, since there is no bobbin which creates magnetic resistance, the magnetic flux generated by the solenoid coil can be efficiently passed through the valve body.

[0022] In order to make the fluid control valve of the present invention a so-called normally closed type, it is possible to further include an elastic body that biases the seating surface toward the valve seat surface, and the actuator unit drives the valve body in a direction to open the valve by magnetic force. In this configuration, in order to reliably seat the seating surface on the valve seat surface when the valve body is not driven, it is desirable that the valve body and the elastic body are bonded. Here, the bonding includes mechanical bonding, welding bonding, and adhesive bonding.

[0023] In addition, the fluid control device according to the present invention is characterized in that it comprises the above-mentioned fluid control valve, a fluid sensor that measures the flow rate or pressure of the fluid, and a control unit that controls the opening degree of the fluid control valve based on a measurement value measured by the fluid sensor and a predetermined target value. Effect of the Invention

[0024] According to the present invention thus configured, by reducing the magnetic resistance of the magnetic path including the valve body, it is possible to perform fluid control with less current or voltage. [Brief description of the drawings]

[0025] [Figure 1] 1 is a schematic diagram showing a fluid control device according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a cross-sectional view of the fluid control valve (closed state) of the embodiment. [Diagram 3] FIG. 2 is a partially enlarged cross-sectional view of the fluid control valve (open state) of the embodiment. [Figure 4] 3A and 3B are a plan view and a perspective view of a support member (elastic body) and a valve body of the embodiment as viewed from a seating surface. [Diagram 5] 5A to 5C are partially enlarged cross-sectional views showing states before and after distance adjustment according to the embodiment. [Figure 6] FIG. 11 is a partially enlarged cross-sectional view of a fluid control valve (open state) according to a modified embodiment. [Figure 7] FIG. 11 is a cross-sectional view of a fluid control valve (closed state) according to a modified embodiment. [Figure 8] FIG. 11 is a cross-sectional view of a fluid control valve (closed state) according to a modified embodiment. [Figure 9] FIG. 11 is a cross-sectional view of a fluid control valve (closed state) according to a modified embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a fluid control device using a fluid control valve according to the present invention will be described with reference to the drawings. In addition, in any of the drawings shown below, for the purpose of easy understanding, some parts are omitted or exaggerated in schematic form as appropriate. The same components are denoted by the same reference numerals and the description thereof is omitted as appropriate.

[0027] <Device configuration> The fluid control device 100 of this embodiment is used in a semiconductor manufacturing process, for example by being incorporated into a semiconductor manufacturing apparatus, and is provided, for example, in one or more gas supply lines connected to a semiconductor processing chamber to control the flow rate of process gas flowing through each gas supply line.

[0028] Specifically, the fluid control device 100 is a so-called differential pressure type mass flow controller (differential pressure type MFC), and as shown in FIG. 1, includes a flow path block 2 in which an internal flow path 2R is formed, and a fluid control device 3 including a flow sensor 31 and a fluid control valve 32 mounted on the flow path block 2.

[0029] The flow path block 2 is rectangular, and a flow rate sensor 31 and a fluid control valve 32 are provided on a predetermined surface. A concave accommodating recess 2M for mounting the fluid control valve 32 is formed on a predetermined surface of the flow path block 2, and the internal flow path 2R is divided into an upstream flow path 2R1 and a downstream flow path 2R2 by the accommodating recess 2M. One end of the upstream flow path 2R1 opens on, for example, the bottom surface of the accommodating recess 2M, and one end of the downstream flow path 2R2 opens on, for example, the bottom surface of the accommodating recess 2M.

[0030] The fluid control device 3 controls the fluid in the internal flow path 2R, and has a flow sensor 31 that measures the flow rate of the fluid flowing through the internal flow path 2R, and a fluid control valve 32 provided upstream of the flow sensor 31. The valve opening of the fluid control valve 32 is feedback-controlled by the control unit 4, which will be described later.

[0031] The flow sensor 31 is a differential pressure type flow sensor, and has an upstream pressure sensor 31a provided upstream of a fluid resistance element 33 such as a restrictor or orifice provided in the internal flow path 2R, and a downstream pressure sensor 31b provided downstream of the fluid resistance element 33. The upstream pressure sensor 31a and the downstream pressure sensor 31b are attached in a row together with the fluid control valve 32 on a predetermined surface of the flow path block 2. A flow rate calculation unit 4a of the control unit 4 described later calculates a flow rate Q flowing through the internal flow path 2R using the upstream pressure P1 of the fluid resistance element 33 detected by the upstream pressure sensor 31a and the downstream pressure P2 of the fluid resistance element 33 detected by the downstream pressure sensor 31b.

[0032] The fluid control valve 32 is provided upstream of the differential pressure flow sensor 31. Specifically, the fluid control valve 32 is a solenoid valve (electromagnetic valve) that controls the flow rate by moving a valve body toward and away from a valve seat using a solenoid. In this embodiment, it is a so-called normally closed type that is in a fully closed state when the valve body is not driven. The fluid control valve 32 is controlled by a valve control section 4b of the control section 4. A detailed configuration of the fluid control valve 32 will be described later.

[0033] The control unit 4 has a flow rate calculation unit 4a that calculates a flow rate Q flowing through the internal flow path 2R based on the upstream pressure P1 and the downstream pressure P2, and a valve control unit 4b that controls the fluid control valve 32 based on the flow rate Q calculated by the flow rate calculation unit 4a and a target flow rate (set value). The control unit 4 is a so-called computer equipped with, for example, a CPU, a memory, an A / D·D / A converter, and an input / output means, and performs the functions of the flow rate calculation unit 4a, the valve control unit 4b, etc. by executing a flow rate control program stored in the memory and cooperating with various devices.

[0034] <Detailed configuration of the fluid control valve 32> As shown in Figs. 2 and 3, the fluid control valve 32 of this embodiment includes an orifice 5 having a planar valve seat surface 5a, a valve body 6 having a planar seat surface 6a that seats in surface contact with the valve seat surface 5a, and an actuator unit 7 that drives the valve body 6 by magnetic force.

[0035] The orifice 5 has a generally solid-of-rotation shape, and is accommodated in the accommodation recess 2M of the flow path block 2, as shown in Fig. 2 and Fig. 3. The orifice 5 has an annular valve seat surface 5a formed on an upper surface facing the opening side of the accommodation recess 2M. The orifice 5 is made of a non-magnetic material, for example, austenitic stainless steel such as SUS316L.

[0036] In addition, the orifice 5 has a through hole 51 formed in the center inside the valve seat surface 5a, penetrating from the valve seat surface 5a side to the opposite side to the valve seat surface 5a. This through hole 51 communicates with the upstream flow path 2R1 that opens to the bottom surface of the accommodation recess 2M. A seal member S1 such as an O-ring is provided between the periphery of the through hole 51 and the bottom surface of the accommodation recess 2M to provide a liquid-tight seal.

[0037] Furthermore, the orifice 5 is formed with a lead-out passage 52 for allowing the fluid that has flowed in from the valve seat surface 5a to flow out to the downstream flow passage 2R2. The lead-out passage 52 in this embodiment is a through hole that penetrates from the valve seat surface 5a side to the opposite side of the valve seat surface 5a on the outer side of the valve seat surface 5a. The lead-out passage 52 is connected to the upstream flow passage 2R1 that opens into the bottom surface of the installation recess 2M.

[0038] The valve body 6 has a generally rotary body shape, and is disposed opposite the orifice 5 accommodated in the accommodation recess 2M, as shown in Figures 2 and 3. The valve body 6 also has a protrusion 61 having a flat seating surface 6a on its top surface. The valve body 6 is made of a magnetic material, for example, electromagnetic stainless steel such as KM45.

[0039] The valve body 6 is accommodated in a mounting block 8 that is attached to a predetermined surface (upper surface) of the flow path block 2. The mounting block 8 is made of a magnetic material, such as electromagnetic stainless steel, for example, KM45. The valve body 6 is supported by a support member 9 made of an elastic material, such as a leaf spring, with respect to the mounting block 8. The support member 9 supports the valve body 6 with the seating surface 6a facing the valve seat surface 5a. Specifically, as shown in FIG. 4, the support member 9 is annular, and the protrusion 61 of the valve body 6 is inserted into a central opening 91 to support the valve body 6. The support member 9 and the valve body 6 are integrally formed by welding, for example, laser welding. The support member 9 and the valve body 6 may be integrally formed by mechanical joining or adhesive joining. The support member 9 is made of a non-magnetic material, such as austenitic stainless steel, for example, SUS316L. Furthermore, the support member 9 has spring properties and is made of a corrosion-resistant material that is suitable for a semiconductor gas-contacting portion, taking into consideration magnetic permeability.

[0040] 3, the valve body 6 is formed with a circular seating surface 6a corresponding to the annular valve seating surface 5a. When the driving force of the actuator unit 7 is not applied to the valve body 6, that is, when the fluid control valve 100 is assembled, the support member 9 is elastically deformed, and the seating surface 6a is biased by the support member 9 against the valve seating surface 5a by the elastic force thereof, so that the seating surface 6a is seated on the valve seating surface 5a.

[0041] The mounting block 8 also fixes the orifice 5 accommodated in the accommodation recess 2M by being attached to the flow path block 2. Specifically, the surface (lower surface) of the mounting block 8 facing the flow path block 2 comes into contact with the upper surface of the orifice 5, and the lower surface of the orifice 5 is pressed and fixed against the bottom surface of the accommodation recess 2M via a seal member S1. A seal member S2 such as a metal seal is provided between the mounting block 8 and the flow path block 2 to provide a liquid-tight seal.

[0042] As shown in Figures 2 and 3, the actuator unit 7 has an iron core 71 arranged opposite to the surface 6b of the valve body 6 opposite the seating surface 6a, a solenoid coil 72 wound around the iron core 71, and a casing 73 that houses the iron core 71 and the solenoid coil 72.

[0043] The iron core 71 has a generally cylindrical shape, with one end (the upper end in FIG. 2) connected to the casing 73 and the other end (the lower end in FIG. 2) facing the surface 6b opposite to the seating surface 6a of the valve body 6. The iron core is made of a magnetic material, for example, carbon steel for machine construction such as S45C.

[0044] Solenoid coil 72 is wound around the outer circumferential surface of iron core 71, specifically, wound around bobbin 721 through which iron core 71 is inserted. Here, bobbin 721 is provided so as to be slidable relative to iron core 71. Note that bobbin 721 is formed of a non-magnetic material, for example, austenitic stainless steel such as SUS316L.

[0045] The casing 73 has a cylindrical shape, and its upper wall portion is connected to the upper end portion of the iron core 71. An elastic body 74 such as a wave spring is provided between the upper wall portion of the casing 73 and the solenoid coil 72 (specifically, the upper end portion of the bobbin 721). The casing 73 is made of a magnetic body, for example, carbon steel for machine construction such as S45C. The casing 73 and the iron core 71 may be integrally formed.

[0046] In addition, the casing 73 is attached to the mounting block 8, and by attaching the casing 73 to the mounting block 8, the iron core 71 connected to the casing 73 is arranged facing the surface 6b opposite the seating surface 6a of the valve body 6.

[0047] The casing 73 extends to a position surrounding the valve body 6, forming a magnetic path that guides the magnetic flux generated by the solenoid coil 72 to the periphery of the valve body 6. The position surrounding the periphery of the valve body 6 is a position facing the outer peripheral surface of the valve body 6 in a direction perpendicular to the advancing and retreating direction of the valve body 6. With this configuration, the surface 6b (upper surface in Figs. 2 and 3) opposite to the seating surface 6a of the valve body 6 is located closer to the iron core 71 (upper side) than the tip surface (lower surface in Figs. 2 and 3) of the casing 73 on the flow path block 2 side. Specifically, the casing 73 extends to a position surrounding at least the upper half of the outer peripheral surface of the valve body 6 around the valve body 6 in the valve closed state, for example.

[0048] Thus, in this embodiment, as shown in FIGS. 2, 3 and 5, a distance adjustment mechanism 10 for adjusting the distance between the iron core 71 and the valve body 6 is provided.

[0049] This distance adjustment mechanism 10 adjusts the distance between the opposing surfaces of the iron core 71 and the valve body 6, and is interposed between the casing 73 and the mounting block 8, and is constituted by the casing 73 and the mounting block 8. Here, the opposing surfaces of the iron core 71 and the valve body 6 are the lower end surface 71a of the iron core 71 and the surface 6b of the valve body 6 opposite the seating surface 6a.

[0050] Specifically, the distance adjustment mechanism 10 has a male threaded portion 10a formed on the outer peripheral surface of the casing 73, and a female threaded portion 10b formed on the mounting block 8, into which the male threaded portion 10a screws. With this configuration, the casing 73 is attached to the mounting block 8 by screwing the male threaded portion 10a and the female threaded portion 10b together. In addition, by rotating the casing 73 relative to the mounting block 8, the casing 73 advances and retreats in the axial direction relative to the mounting block 8, as shown in FIG. 5, and the distance between the opposing surfaces of the iron core 71 and the valve body 6 is adjusted.

[0051] 2, 3 and 5, the mounting block 8 is provided with a set screw 11, which is movable forward and backward with respect to the casing 73, on a side wall portion 81 on which the female thread portion 10b is formed, and serves as a fixing portion for fixing the casing 73 to the mounting block 8. The set screw 11 is movable forward and backward in a direction perpendicular to the direction in which the casing 73 is moved by the distance adjustment mechanism 10.

[0052] Specifically, the casing 73 has a cylindrical end portion 73x at the tip portion closer to the flow path block than the male thread portion 10a, and the set screw 11 presses against the cylindrical end portion 73x to fix the casing 73 to the mounting block 8. The cylindrical end portion 73x in this embodiment has the same diameter as the housing main body portion 73y that houses the solenoid coil 72 in the casing 73. In other words, the casing 73 does not have a flange portion for mounting to the mounting block 8.

[0053] More specifically, as shown in Fig. 3, the mounting block 8 has an annular slit 8S that accommodates the cylindrical end 73x, and a set screw 11 is provided in a radially outer side wall portion 811 that forms the slit 8S. A radially inner side wall portion 812 that forms the slit 8S is provided so as to surround the outer peripheral surface of the valve body 6. The cylindrical end 73x is pressed and fixed to the radially inner side wall portion 812 that forms the slit 8S by the set screw 11. With this configuration, the magnetic flux that reaches the cylindrical end 73x of the casing 73 flows to the valve body 6 through the radially inner side wall portion 812.

[0054] In this embodiment, even if the casing 73 and the iron core 71 move relative to the mounting block 8 by the distance adjustment mechanism 10, the relative position between the solenoid coil 72 and the mounting block 8 (valve body 6) does not change (see FIG. 5). Specifically, the solenoid coil 72 is provided so as to be slidable relative to the iron core 71 and the casing 73. Also, the solenoid coil 72 is configured to be pressed toward the mounting block 8 by a wave spring 74 provided between the upper wall of the casing 73 and the solenoid coil 72 (the upper end of the bobbin 721). This wave spring 74 fixes the solenoid coil 72 by absorbing dimensional tolerances. Note that if the dimensional precision of each member is sufficient, the wave spring 74 may not be provided.

[0055] 3, a diaphragm seal 12 is provided between the lower end surface of the bobbin 721 and the upper end surface of the mounting block 8 to provide a liquid-tight seal between the lower end surface of the bobbin 721 and the upper end surface of the mounting block 8. The diaphragm seal 12 is made of a non-magnetic material, for example, austenitic stainless steel such as SUS316L.

[0056] Next, the operation of the fluid control valve 32 of this embodiment will be briefly described.

[0057] In the fully closed state where no current flows through the solenoid coil 72 of the actuator unit 7, the valve body 6 is biased toward the orifice 5 by the elastic force of the support member 9, and the seating surface 6a of the valve body 6 is in pressing contact with the valve seat surface 5a of the orifice 5.

[0058] When a current is applied to the solenoid coil 72, a magnetic flux is generated by the solenoid coil 72, and the magnetic flux flows to the valve body 6 through the iron core 71 and the casing 73. As a result, the valve body 6 is attracted to the iron core 71, and the seating surface 6a of the valve body 6 is separated from the valve seat surface 5a of the orifice 5, resulting in an open valve state. The valve opening degree of the fluid control valve 32 is adjusted by controlling the current passed through the solenoid coil 72. Here, the cylindrical end 73x of the casing 73 extends to a position surrounding the valve body 6, and magnetic flux flows from the cylindrical end 73x of the casing 73 to the valve body 6 through the side wall portion 812 on the radial inside of the slit 8S. This reduces the magnetic resistance of the magnetic path including the valve body 6, thereby improving the magnetic characteristics.

[0059] <Effects of this embodiment> According to the fluid control device 100 of the present embodiment thus configured, since the orifice 5 having the valve seat surface 5a is housed in the flow path block 2, the length of the flow path through the valve seat surface 5a can be shortened, and this is expected to reduce the gas contact area. In this configuration, the casing 73 made of a magnetic material that houses the iron core 71 and the solenoid coil 72 extends to a position surrounding the valve element 6 made of a magnetic material, forming a magnetic path that guides the magnetic flux generated by the solenoid coil 72 to the periphery of the valve element 6, so that the magnetic resistance of the magnetic path including the valve element 6 can be reduced and the magnetic characteristics can be improved. As a result, it becomes possible to perform fluid control with less current or voltage.

[0060] In addition, in this embodiment, the magnetic resistance of the magnetic path including the valve body 6 is reduced to improve the magnetic characteristics, thereby increasing the attractive force to the iron core 71 when the solenoid coil 72 is energized. As a result, the elastic force (spring constant) of the support member 9 that presses the seating surface 6a against the valve seating surface 5a can be increased, and seat leaks (liquid leakage) in the fully closed state can be suppressed.

[0061] Furthermore, in this embodiment, since the distance adjustment mechanism 10 for adjusting the distance between the iron core 71 and the valve body 6 is provided, the distance between the iron core 71 and the valve body 6 can be adjusted (increased or decreased) to an optimal magnetic field (magnetic flux density) by adjusting the distance between the iron core 71 and the valve body 6 with the distance adjustment mechanism 10. This allows the valve opening degree at full open to be adjusted, for example. For example, by flowing a fluid while applying a constant voltage, the valve opening degree can be set so that the fluid has a full scale (FS) that is to be adjusted. Also, for example, when it is desired to control a minute flow rate, the magnetic force attracting the valve body 6 is weakened by increasing the distance between the iron core 71 and the valve body 6, and it becomes possible to control the minute flow rate.

[0062] <Other embodiments> For example, the distance adjustment mechanism 10 in the above embodiment is configured with the male thread portion 10a and the female thread portion 10b, but may be configured with a set screw 11 as shown in Fig. 6. In this case, it is considered to form an annular slit 8S in the mounting block 8 to accommodate the cylindrical end portion 73x, and fix the cylindrical end portion 73x with the set screw 11 after adjusting the cylindrical end portion 73x in the vertical direction in the slit 8S.

[0063] Furthermore, the male thread portion 10a and the female thread portion 10b of the distance adjustment mechanism 10 of the above embodiment may be reversed, that is, the male thread portion 10a may be formed on the mounting block 8, and the female thread portion 10b may be formed on the inner peripheral surface of the casing.

[0064] Furthermore, as shown in Fig. 7, the solenoid coil 72 may be formed using a plurality of wires having different wire diameters. Specifically, the solenoid coil 72 is divided into a plurality of coil elements 72A-72C along the axial direction of the iron core 71. Although the solenoid coil 72 is divided into three coil elements in Fig. 7, it may be divided into two coil elements, or into four or more coil elements. The coil elements 72A-72C are wound around bobbins 721A-721C, respectively.

[0065] The wire diameters of the coil elements 72A to 72C are different from one another. In Fig. 7, the inner and outer diameters of the coil elements 72A to 72C are substantially the same, and the coil elements 72A to 72C with a larger wire diameter have a smaller number of turns.

[0066] If the wire diameter is made smaller along the axial direction of the iron core 71 toward the valve body 6, the heat generation of the solenoid coil 72 (coil element 72A) on the valve body 6 side can be suppressed, and the temperature effect of the heat generated by the coil element 72A on the fluid can be reduced. Furthermore, when a thermal flow sensor is used together with the fluid control valve 32, the temperature effect of the heat generated by the coil element 72A on the thermal flow sensor can be reduced.

[0067] Furthermore, if the wire diameter is increased along the axial direction of the iron core 71 toward the valve body 6, the heat generation of the solenoid coil 72 (coil element 72A) on the valve body 6 side can be increased, and the fluid flowing through the fluid control valve 32 can be heated. For example, if the fluid flowing through the fluid control valve 32 is a gas with a low vapor pressure, the heat generated by the coil element 72A can prevent the gas from liquefying, and corrosion of the valve body 6 and the like caused by liquefaction can be prevented. The solenoid coil 72 may be divided along the radial direction of the iron core 71 (a configuration having a radially inner coil element and a radially outer coil element) in addition to being divided along the axial direction of the iron core 71.

[0068] 8, the solenoid coil 72 may be an air-core coil (also called a bobbinless coil) that does not use a bobbin 721. With this configuration, since there is no bobbin 721 that becomes magnetic resistance, the magnetic flux generated by the solenoid coil 72 can efficiently pass through the valve body 6.

[0069] Furthermore, as shown in FIG. 9, the casing 73 may have a thin portion 73a located inside the mounting block 8 and a thick portion 73b located outside the mounting block 8 and having a wall thickness greater than that of the thin portion 73a.

[0070] Here, the thin portion 73a has a male thread portion 10a formed on its outer peripheral surface, and the thick portion 73b is formed on the opposite side of the thin portion 73a from the flow path block 2. The thin portion 73a and the thick portion 73b are configured by a housing main body portion 73y. In FIG. 9, the inner peripheral surface of the thin portion 73a and the inner peripheral surface of the thick portion 73b are continuous without a step, but a step may be present. Furthermore, the thick portion 73b has a uniform cross-sectional shape along the axial direction of the iron core 71, but it does not have to have the same cross-sectional shape along the axial direction.

[0071] With this configuration, since the casing 73 has the thick portion 73b, the magnetic field lines are less likely to leak to the outside, and the magnetic field lines can efficiently pass through the valve body 6, making it easier to pull up the valve body 6. Also, since the thick portion 73b is formed on the side opposite the flow path block 2 from the thin portion 73a where the male thread portion 10a is formed, the outer diameter of the thin portion 73a can be made smaller, eliminating the need to increase the size of the mounting block 8. Also, since the thick portion 73b is operated when rotating the casing 73 relative to the mounting block 8, the rotation torque is reduced, making it easier to rotate the casing 73.

[0072] Furthermore, the fluid control valve 32 of the above embodiment may be a so-called normally open type that is in a fully open state when the valve body 6 is not driven, in addition to the normally closed type. In the normally closed type, when a current flows through the solenoid coil 72, a magnetic flux is generated by the solenoid coil 72, and the magnetic flux flows through the valve body 6 through the iron core 71 and the casing 73. As a result, the valve body 6 is attracted to the iron core 71, and the seating surface 6a of the valve body 6 is separated from the valve seat surface 5a of the orifice 5 to be in an open state. However, it is also possible to change the configuration to a normally open type fluid control valve by adjusting the balance between the support force of the support member 9 that supports the valve body 6 and the magnetic force of the magnetic body of the valve body 6.

[0073] In the above embodiment, the fluid control valve 32 is disposed upstream of the flow rate sensor 31 , but it may be disposed downstream of the flow rate sensor 31 .

[0074] In the above embodiment, a pressure type flow sensor is used as the flow sensor 31 of the fluid control device 100, but a thermal type flow sensor may also be used. In this case, it is considered to install the thermal type flow sensor upstream of the fluid control valve 32. In addition to the flow sensor, a fluid sensor such as a pressure sensor may also be used.

[0075] The fluid control device 100 is not limited to the pressure type and the heat type, but may be one in which a position sensor is provided in the fluid control valve 32 to measure the relative position between the valve seat surface 5a and the seat surface 6a, and the valve opening degree is feedback-controlled based on the measurement value of the position sensor. The fluid control device of the present invention is not limited to the flow rate control device of the above embodiment, but may also be applied to a pressure control device that controls the pressure of a fluid.

[0076] 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. [Explanation of symbols]

[0077] 100... Fluid control device 2. Flow passage block 2R: Internal flow path 2M ···Housing recess 32 Fluid control valve 31 Fluid sensor 4 Valve control section 5. Orifice 5a...Valve seat surface 6 Valve body 6a Seating surface 7 Actuator section 71 Iron core 72 Solenoid coil 72A···Coil element 72B Coil element 72C···Coil element 73 Casing 73x...Cylindrical end 73a Thin section 73b...Thick part 8 Mounting block 8S: Circular slit 811: Radial outer side wall 812: Radially inner side wall 10...Distance adjustment mechanism 10a Male thread 10b Female thread 11...Set screw

Claims

1. A channel block in which an internal channel is formed, The flow path block is housed in an orifice having a valve seat surface, A valve body made of a magnetic material having a seating surface that sits on the valve seat surface, The valve body is driven by a magnetic force and an actuator unit is provided. The actuator section is An iron core is provided facing the surface opposite to the seating surface of the valve body, The solenoid coil wound around the aforementioned iron core, It has an iron core and a casing made of a magnetic material that houses the solenoid coil, A fluid control valve in which the casing extends to a position surrounding the valve body.

2. The fluid control valve according to claim 1, wherein the surface of the valve body opposite to the seating surface is located closer to the iron core than the tip surface of the flow path block on the casing.

3. The fluid control valve according to claim 1, further comprising a distance adjustment mechanism for adjusting the distance between the iron core and the valve body.

4. The aforementioned flow path block is further equipped with a mounting block that houses the valve body, The iron core is fixed to the casing, The fluid control valve according to claim 3, wherein the distance adjustment mechanism is comprised of the casing and the mounting block.

5. The distance adjustment mechanism is, A male threaded portion formed on the outer circumferential surface of the casing or on the mounting block, The fluid control valve according to claim 4, having a female thread formed on the outer circumferential surface of the casing or on the other side of the mounting block, into which the male thread is screwed.

6. The fluid control valve according to claim 5, wherein the mounting block is provided with a fixing portion that is movable back and forth relative to the casing and that fixes the casing to the mounting block.

7. The casing has a cylindrical end at the tip on the flow path block side, The mounting block has a slit for accommodating the cylindrical end, The fixing portion is provided on the side wall portion that forms the slit in the mounting block. The fluid control valve according to claim 6, wherein the cylindrical end is fixed by the fixing portion to the side wall portion forming the slit in the mounting block.

8. The fluid control valve according to any one of claims 5 to 7, wherein the casing has a thin-walled portion located inside the mounting block and a thick-walled portion located outside the mounting block and having a wall thickness greater than that of the thin-walled portion.

9. The iron core and the casing are provided so as to be slidable relative to the solenoid coil. A fluid control valve according to any one of claims 3 to 7, wherein the relative position between the solenoid coil and the valve body does not change regardless of the movement of the iron core and the casing by the distance adjustment mechanism.

10. The fluid control valve according to any one of claims 4 to 7, wherein the flow path block has a receiving recess for accommodating the orifice.

11. The fluid control valve according to claim 10, wherein the mounting block is attached to the flow path block to fix the orifice housed in the housing recess.

12. The fluid control valve according to any one of claims 1 to 7, wherein the solenoid coil is constructed using a plurality of wires having different diameters.

13. The fluid control valve according to any one of claims 1 to 7, wherein the solenoid coil is divided into a plurality of coil elements along the axial direction of the iron core, and the wires of the plurality of coil elements have different wire diameters from each other.

14. The fluid control valve according to any one of claims 1 to 7, wherein the solenoid coil is an air-core coil.

15. The seating surface further comprises an elastic body that biases toward the valve seat surface, The actuator unit drives the valve body in a direction that opens it by magnetic force. A fluid control valve according to any one of claims 1 to 7, wherein the valve body and the elastic body are joined together.

16. A fluid control valve according to any one of claims 1 to 7, A fluid sensor that measures the flow rate or pressure of a fluid, A fluid control device comprising: a control unit that controls the opening degree of the fluid control valve based on a measurement value measured by the fluid sensor and a predetermined target value.

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