Electric valve unit

Abstract

An electric valve unit (10) comprising a flow control valve (22, 22A, 22B, 22C, 22D), wherein the flow control valve (22, 22A, 22B, 22C, 22D) comprises the following: a first valve chamber (38) which is connected to an inlet flow path (54), a first valve seat (40) formed in the first valve chamber (38) and comprising an opening (56a) of a first flow path (56), a first valve element (44) facing the first valve seat (40) and forming a gap between the first valve element (44) and the first valve seat (40) to adjust a flow rate of a chemical solution, a first shaft element (46, 46A, 46B, 46C, 46D) which is displaced in a second direction while carrying the first valve element (44), and a first motor (28) which drives the first shaft element (46, 46A, 46B, 46C, 46D), wherein the first shaft element (46, 46A, 46B, 46C, 46D) generates a thrust force in the second direction towards the first valve seat (40) by means of gas pressure, thereby bringing the first valve element (44) into contact with the first valve seat (40).

Description

BACKGROUND OF THE INVENTION FIELD OF THE INVENTION

[0001] The present invention relates to an electric valve unit with a flow control valve. DESCRIPTION OF THE STATE OF THE ART

[0002] For example, micromachining is performed on substrates in the manufacture of semiconductor devices, liquid crystal display devices, and the like. Valve units are used for micromachining to supply processing fluids such as etching agents or photoresist fluids. As a valve unit for supplying a chemical solution, a valve unit is known that includes a flow control valve for adjusting the flow rate of the fluid and a check valve with a check function, as described, for example, in JP 7175366 B1.

[0003] The valve unit in JP 7175366 B1 drives the flow control valve with compressed air. The opening of the flow control valve is adjusted using a screw mechanism. SUMMARY OF THE INVENTION

[0004] The valve unit in JP 7175366 B1 requires manual work by an operator to adjust the flow control valve. Adjusting the flow control valve is extremely demanding and requires a high level of expertise and experience. To facilitate the adjustment of the valve unit, it is therefore conceivable to electrify the valve unit and drive the flow control valve with a stepper motor.

[0005] However, if the flow control valve is electrified, the problem arises that the supply of the chemical solution cannot be stopped if the power supply is interrupted for any reason while the valve is open.

[0006] The object of the present invention is to solve the above-mentioned problems.

[0007] One aspect of the invention is an electric valve unit comprising a flow control valve, the flow control valve comprising a first valve chamber communicating with an inlet flow path, a first valve seat formed in the first valve chamber and including an opening of the first flow path, a first valve element facing the first valve seat and forming a gap between the first valve element and the valve seat to adjust the flow rate of a chemical solution, a first shaft element displaced in a second direction while supporting the first valve element, and a first motor driving the first shaft element, and the first shaft element generating a thrust force toward the first valve seat in the second direction by gas pressure, thereby bringing the first valve element into contact with the first valve seat.

[0008] The electric valve unit of the above aspect can stop the supply of the solution by closing the flow control valve with the gas pressure when the supply of the electric power is stopped.

[0009] The above and other objects, features and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings in which a preferred embodiment of the present invention is shown by way of illustrative example. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a diagram showing a configuration example of a chemical solution supply system. Fig. 2 is a cross-sectional view of an electric valve unit of Fig. 1. Fig. 3A is a partially enlarged cross-sectional view of a flow control valve of Fig. 2 and Fig. 3B is a partially enlarged cross-sectional view of a suck-back valve of Fig. 2. Fig. 4A is a cross-sectional view of the flow control valve in the open position and Fig. Figure 4B is a diagram explaining the operation of the flow control valve during gas pressure supply. Fig. 5A is a cross-sectional view of the flow control valve in the open position according to the second embodiment, and Fig. Figure 5B is a diagram showing the operation of the flow control valve of Fig. 5A during gas pressure supply is explained. Fig. 6A is a cross-sectional view of the flow control valve in the open position according to the third embodiment and Fig. Figure 6B is a cross-sectional view of the flow control valve along VIB-VIB of Fig. 6A. Fig. 7 is a diagram showing the operation of the flow control valve of Fig. 6A during gas pressure supply explained. Fig. 8A is a cross-sectional view of the flow control valve in the open position according to the fourth embodiment, and Fig. Figure 8B is a cross-sectional view along VIIIB-VIIIB of Fig. 8A. Fig. 9 is a diagram showing the operation of the flow control valve of Fig. 8A during gas pressure supply explained. Fig. 10A is a cross-sectional view of the flow control valve in the open position according to the fifth embodiment, and Fig. 10B is a diagram showing the operation of the flow control valve of Fig. 10A during gas pressure supply is explained. DETAILED DESCRIPTION OF THE INVENTION (First Embodiment)

[0010] An electric valve unit 10 according to the present embodiment is used in a chemical solution supply system 12 as shown in Fig. 1 as an example. The illustrated chemical solution supply system 12 includes a chemical solution tank 14, a separation tank 16, a discharge pump 18, the electric valve unit 10, a nozzle 20, a control circuit 21, and a gas supply source 45.

[0011] The chemical solution tank 14 stores a chemical solution. The chemical solution tank 14 is supplied with nitrogen gas, for example, and the chemical solution is transferred to the separation tank 16 by the gas pressure. The separation tank 16 removes air bubbles from the chemical solution and stores a predetermined amount of the chemical solution. The metering pump 18 is connected to a downstream side of the separation tank 16. The metering pump 18 sucks the chemical solution from the separation tank 16 and supplies the chemical solution to the nozzle 20. The electric valve unit 10 is provided in a chemical solution supply flow path 18a connecting the metering pump 18 and the nozzle 20.

[0012] The gas supply source 45 includes, for example, a storage tank and a valve that opens in the event of a power failure. When the power supply to the chemical solution supply system 12 is interrupted, the valve of the gas supply source 45 opens to supply the compressed gas stored in the storage tank to the electric valve unit 10.

[0013] The control circuit 21 includes, for example, a processor and a memory that stores the instructions executed by the processor. The processor executes the instructions stored in the memory, thereby causing the control circuit 21 to control the operation of each part of the chemical solution supply system 12 and the operation of the electric valve unit 10.

[0014] The electric valve unit 10, for example, is a module that integrates a flow control valve 22 and a suck-back valve 24. In the electric valve unit 10, the flow control valve 22 controls the supply and stopping of the chemical solution and the flow rate of the chemical solution. The suck-back valve 24 performs a suck-back operation to suck back the chemical solution remaining at the tip of the nozzle 20 after the supply of the chemical solution is stopped. In the chemical solution supply system 12, the electric valve unit 10 precisely adjusts the supply amount of the chemical solution. The configuration of each part of the electric valve unit 10 is described below.

[0015] In the following description, the terms of the first direction and the second direction are used to indicate the positional relationship and operation of each part of the electric valve unit 10 as shown in Fig. 2. The first and second directions are perpendicular to each other. The first direction is the direction in which an inlet port 34 and an outlet port 36 of the chemical solution are arranged, and generally coincides with the flow direction of the chemical solution. The second direction is perpendicular to the first direction and generally coincides with the displacement direction of a first valve element 44. One of the second directions is also referred to as downward, down, or bottom, and the other of the second directions is also referred to as upward or up. In this description, the terms "top" and "bottom" essentially mean the arrangement relationship or the movement direction of the elements within the electric valve unit 10 and do not limit the arrangement direction of the electric valve unit 10.

[0016] As in Fig. As shown in Figure 2, the electric valve unit 10 includes a main body 26 housing the flow control valve 22 and the suck-back valve 24, a drive unit 32 housing a first motor 28 and a second motor 30, and a gas flow path member 33. The gas flow path member 33 is a plate-like member disposed between the main body 26 and the drive unit 32. The gas flow path member 33 is provided with a gas flow path 33a that allows the flow of supplied compressed gas when a power failure occurs.

[0017] The main body 26 has the inlet opening 34 and the outlet opening 36 arranged along the first direction. The inlet opening 34 opens at a first end portion 26a of the main body 26 in the first direction. A tube (hose) for chemical solutions extending from the dispenser pump 18 (see Fig. 1) is connected to the inlet opening 34. The inlet opening 34 introduces the chemical solution into the electric valve unit 10. The outlet opening 36 opens at a second end portion 26b of the main body 26 in the first direction. The outlet opening 36 allows the chemical solution to be discharged from the electric valve unit 10. A chemical tube connecting the nozzle 20 (see Fig. 1) and the electric valve unit 10 is connected to the outlet port 36.

[0018] The main body 26 includes the flow control valve 22 and the suction-back valve 24 between the inlet port 34 and the outlet port 36. The flow control valve 22 is located adjacent to the inlet port 34, and the suction-back valve 24 is located adjacent to the outlet port 36.

[0019] As in Fig. 3A, the flow control valve 22 includes a first valve chamber 38, a first valve seat 40, a first cylinder chamber 42, the first valve element 44, a first shaft member 46, and a first screw mechanism 48. The first valve chamber 38 is formed inside the main body 26 and is located near a lower end of the main body 26 in the second direction. A lower end portion of the first valve chamber 38 is provided with an opening that communicates with an inlet flow path 54. The inlet flow path 54 is a flow path that extends in a first direction from the inlet port 34 and allows the inlet port 34 and the first valve chamber 38 to communicate with each other.

[0020] The first valve seat 40 is provided in the first valve chamber 38. The first valve seat 40 has a tubular shape that extends upward and just before the lower end of the first valve chamber 38. A first flow path 56 is formed in a central portion of the first valve seat 40. A first opening 56a of the first flow path 56 is formed at the upper end of the first valve seat 40. The first flow path 56 is bent into an L-shape within the main body 26 and extends in the first direction toward the outlet opening 36. The first flow path 56 allows the first valve chamber 38 and a second valve chamber 64 of the suck-back valve 24 to communicate with each other (see Fig. 2).

[0021] The first cylinder chamber 42 is formed above the first valve chamber 38. The first cylinder chamber 42 extends in the second direction within the main body 26 and opens to an upper portion 26c of the main body 26. The first cylinder chamber 42 receives the first shaft member 46 in a manner that allows displacement in the second direction.

[0022] The gas flow path element 33 is arranged on the main body 26. The gas flow path element 33 has a first through-hole 33b communicating with an upper part of the first cylinder chamber 42. The gas flow path 33a of the gas flow path element 33 communicates with the first cylinder chamber 42 via the first through-hole 33b.

[0023] The first valve element 44 is disposed between the first valve chamber 38 and the first cylinder chamber 42. The first valve element 44 is formed of an elastic material such as rubber. The first valve element 44 includes a stem portion 44a and a diaphragm 44b. The stem portion 44a is located at a central portion of the first valve element 44 and extends in a rod-like shape in the second direction. When the stem portion 44a is pushed downward, it comes into contact with the first valve seat 40 to seal the first opening 56a in a liquid-tight manner. When the stem portion 44a and the first valve seat 40 are separated, the chemical solution flows from the first valve chamber 38 toward the first flow path 56 at a flow rate corresponding to a gap between the stem portion 44a and the first valve seat 40.

[0024] The membrane 44b covers an upper portion of the first valve chamber 38 and separates the first valve chamber 38 and the first cylinder chamber 42. The membrane 44b prevents the chemical solution from leaking into the first cylinder chamber 42.

[0025] The first shaft member 46 supports the first valve element 44 and displaces the first valve element 44 in the second direction. The first shaft member 46 has a first holder portion 46a and a first piston portion 46b. The first holder portion 46a is located at the lower portion of the first shaft member 46 and holds the shaft portion 44a of the first valve element 44. The first piston portion 46b is located above the first holder portion 46a and is connected to the first holder portion 46a.

[0026] The first piston part 46b is in airtight contact with an inner wall 42c of the first cylinder chamber 42 and slides on the inner wall 42c of the first cylinder chamber 42. The first piston part 46b divides the first cylinder chamber 42 into a first empty chamber 42a on an upper side and a second empty chamber 42b on a lower side. The first empty chamber 42a communicates with the gas flow path 33a, and the second empty chamber 42b is open to the atmosphere via a vent path (not shown).

[0027] The first piston portion 46b has a first receiving chamber 46c at its central portion for receiving the first screw mechanism 48. The first receiving chamber 46c is an empty chamber with a substantially cylindrical shape. An upper end wall 46d is formed at an upper end of the first receiving chamber 46c, and a lower end wall 46e is formed at a lower end thereof. The surfaces of the upper end wall 46d and the lower end wall 46e are smooth.

[0028] The first screw mechanism 48 includes an internally threaded portion 58 and a threaded rod 60. The internally threaded portion 58 is formed from an elastically deformable member and is cylindrical. An inner peripheral portion 58c of the female screw portion 58 is provided with a screw groove and engages a screw thread formed on an outer peripheral surface 60a of the threaded rod 60. The female screw portion 58 converts the rotational displacement of the threaded rod 60 into a linear displacement in the second direction and displaces the first piston portion 46b in the second direction.

[0029] An upper end portion 58a of the female screw part 58 is in contact with the upper end wall 46d of the first accommodating chamber 46c. The upper end portion 58a is radially displaceable relative to the upper end wall 46d. A lower end portion 58b of the female threaded portion 58 is in contact with the lower end wall 46e of the first accommodating chamber 46c. The lower end portion 58b is radially displaceable with respect to the lower end wall 46e. When a thrust force is applied to the first piston portion 46b in the second direction, the female threaded portion 58 expands in diameter so that the screw groove of the inner peripheral portion 58c slides on the screw thread of the threaded rod 60, which will be described later. The first accommodating chamber 46c allows the female threaded portion 58 to expand in diameter.The female screw part 58 is displaced by the pressure of the first piston portion 46b to slide in the second direction with respect to the threaded rod 60, and is displaced downward in the second direction together with the first piston portion 46b. That is, when the flow control valve 22 of the present embodiment is supplied with the gas pressure in the first free chamber 42a located above the first piston portion 46b, the first screw mechanism 48 slides in the second direction, thereby rotating the first shaft member 46 and the first motor 28 (see FIG. Fig. 2) be decoupled.

[0030] As in Fig. As shown in Figure 2, the threaded rod 60 extends upward in the second direction. The upper portion of the threaded rod 60 passes through the first through-hole 33b of the gas flow path member 33 and is connected to the rotating shaft 28a of the first motor 28. The threaded rod 60 rotates integrally with the rotating shaft 28a.

[0031] The first motor 28 is, for example, a stepper motor and rotates at a predetermined number of revolutions and a predetermined speed based on a control signal. The first motor 28 is housed in the drive unit 32.

[0032] As in Fig. 3B, the suck-back valve 24 includes a second valve chamber 64, a second cylinder chamber 66, a second valve element 68, a second shaft element 70, and a second screw mechanism 72. The second valve chamber 64 is located below the main body 26. The second valve chamber 64 is provided with an opening communicating with the first flow path 56 and an opening communicating with an outlet flow path 76. The second valve chamber 64 communicates with the first valve chamber 38 via the first flow path 56. The second valve chamber 64 also communicates with the outlet port 36 via an outlet flow path 76.

[0033] The second cylinder chamber 66 is formed above the second valve chamber 64. The second cylinder chamber 66 extends in the second direction. An upper portion of the second cylinder chamber 66 communicates with the second through-hole 33c of the gas flow path member 33.

[0034] The second valve element 68 is arranged between the second valve chamber 64 and the second cylinder chamber 66. The second valve element 68 has a second shaft portion 68a and a second diaphragm 68b. The second shaft portion 68a is located in a central portion of the second valve element 68. The second valve element 68 extends in a rod-like shape in the second direction and is connected at its upper portion to the second shaft element 70. The second diaphragm 68b consists of a flexible diaphragm and separates the second valve chamber 64 and the second cylinder chamber 66 from each other in a fluid-tight and airtight manner.

[0035] The second shaft member 70 includes a holder portion 70a for holding the second shaft portion 68a and a second piston portion 70b that slides in the second cylinder chamber 66. The holder portion 70a is integrally connected to the second piston portion 70b and is integrally displaced with the second piston portion 70b. In this embodiment, the second piston portion 70b divides the second cylinder chamber 66 into a third free chamber 66a on an upper side and a fourth free chamber 66b on a lower side. The third free chamber 66a communicates with the gas flow path 33a via the second through hole 33c. The fourth free chamber 66b is open to the atmosphere through a vent hole (not shown).

[0036] A screw hole 70c is formed in a central portion of the second piston portion 70b, which forms a part of the second screw mechanism 72. A screw groove is formed on the inner peripheral surface of the screw hole 70c. A second threaded rod 78 is inserted into the screw hole 70c, which forms another part of the second screw mechanism 72. The second threaded rod 78 is provided with a screw thread and engages the screw hole 70c. The second threaded rod 78 extends in the second direction. As shown in Fig. 2, the upper part of the second screw rod 78 is connected to the rotating shaft 30a of the second motor 30.

[0037] The second motor 30 is, for example, a stepper motor and performs a suction back operation by raising and lowering the second valve element 68 under a predetermined control signal.

[0038] The electric valve unit 10 of the present embodiment is configured as described above. The operation of the electric valve unit 10 will be described below.

[0039] In the initial state of the electric valve unit 10, as shown in Fig. 3A, the first valve element 44 of the flow control valve 22 is in contact with the first valve seat 40 and closes the first opening 56a of the first flow path 56. Therefore, in the initial state, the electric valve unit 10 prevents the flow of the chemical solution.

[0040] The flow control valve 22 changes from one to Fig. 3A shown initial state (closed valve state) into one shown in Fig. 4A for supplying the chemical solution based on a control signal from the control unit. At this time, the first motor 28 (see Fig. 2) by a predetermined angle of rotation, thereby separating the first valve element 44 from the first valve seat 40. Thus, the electric valve unit 10 allows the chemical solution to flow toward the nozzle 20 at a flow rate corresponding to the gap between the first valve element 44 and the first valve seat 40.

[0041] When the supply of the predetermined amount of chemical solution is completed, the electric valve unit 10 moves the flow control valve 22 to the Fig. 3A, based on the control signal from the controller. After that, the electric valve unit 10 performs a suction back process. The suction back process is initiated by rotating the second motor 30 of the suction back valve 24 in Fig. 2 is performed to move the second valve element 68 in a direction in which it is pulled upwards. When the second valve element 68 is pulled upwards, the volume of the second valve chamber 64 increases and the pressure in the nozzle 20 (see Fig. 1) Remaining chemical solution is drawn (sucked) into the suction valve 24. This prevents dripping of the chemical solution at the nozzle 20 and prevents particle formation due to the drying out of the chemical solution at the nozzle 20.

[0042] Then, the electric valve unit 10 switches to supplying the next chemical solution, and the flow control valve 22 performs a valve opening operation. At this time, the second valve element 68 of the suction-back valve 24 is returned to the initial position. After that, the electric valve unit 10 repeats the opening / closing operation of the flow control valve 22 and the suction-back operation of the suction-back valve 24 to repeatedly perform the chemical solution supply operation.

[0043] Next, the operation of the electric valve unit 10 in the case where a power failure occurs in the open state of the valve will be described.

[0044] If a power failure occurs when the valve is open according to Fig. 4A occurs, the supply of drive current to the first motor 28 is controlled according to Fig. 2 is interrupted. Therefore, the first valve element 44 cannot be moved to the closed position by the first motor 28 during a power failure. In this case, the valve of the gas supply source 45 is in Fig. 1 is opened and compressed gas, for example nitrogen gas, is supplied from the storage tank to the electric valve unit 10. The compressed gas flows into the first free chamber 42a of the first cylinder chamber 42 via the gas flow path 33a in Fig. 4B.

[0045] As shown in Fig. 4B, when the gas pressure (compressed gas) is supplied to the first free chamber 42a above the first piston part 46b, the pressure in the first free chamber 42a becomes greater than the pressure in the second free chamber 42b. This generates a downward force on the first piston portion 46b (first shaft member 46). This thrust is applied to the engagement area between the screw groove of the internal thread 58 and the screw thread of the threaded rod 60. When a thrust greater than or equal to a predetermined value is applied, the inner peripheral portion 58c of the internal thread 58 expands in diameter so that the screw groove slides on the screw thread of the threaded rod 60. As a result, the internal thread portion 58 is displaced to slide in the second direction with respect to the threaded rod 60 and is displaced downward in the second direction together with the first piston portion 46b.

[0046] Thereafter, the first valve element 44 is displaced downward together with the first shaft element 46, and the first valve element 44 comes into contact with the first valve seat 40 to close the first flow path 56. Therefore, the electric valve unit 10 can stop the supply of the chemical solution when a power failure occurs. (Second version)

[0047] As in Fig. 5A, the flow control valve 22A according to the present embodiment differs from the flow control valve 22 ( Fig. 3A) of the first embodiment by a first shaft element 46A and an internally threaded portion 58A. The flow control valve 22A will be described in detail below, but the same components in the configuration of the flow control valve 22A are assigned the same reference numbers as those in the configuration of the flow control valve 22 described with reference to the Fig. 2 and Fig. 3A, and the detailed description thereof is omitted.

[0048] As in Fig. 5A, in the flow control valve 22A of the present embodiment, the first shaft member 46A has a vent hole 46f that allows the first accommodating chamber 46c to open to the atmosphere. The vent hole 46f is located near the outer peripheral portion of the first accommodating chamber 46c and extends in the second direction as shown in the figure. The vent hole 46f allows the first accommodating chamber 46c and the second free chamber 42b to communicate with each other. The second free chamber 42b is connected to the atmosphere via a vent path (not shown). Accordingly, the first accommodating chamber 46c is connected to the atmosphere via the second free chamber 42b.

[0049] A female screw part 58A of the present embodiment includes a first sealing member 59a and a second sealing member 59b. The first sealing member 59a is provided at the upper end portion 58a of the female screw part 58A. The first sealing member 59a is formed, for example, from an O-ring or the like, and airtightly seals the gap between the upper end wall 46d and the upper end portion 58a of the internally threaded portion 58A. The second sealing member 59b is provided at the lower end portion 58b of the internally threaded portion 58A. The second sealing member 59b is formed, for example, from an O-ring or the like, and airtightly seals the gap between the lower end wall 46e and the lower end portion 58b of the internally threaded portion 58A.

[0050] The flow control valve 22A of the present embodiment, configured as described above, operates as follows when a power failure occurs.

[0051] When compressed gas is supplied through the gas flow path 33a during a power failure, the pressure in the first free chamber 42a increases. Part of the compressed gas enters the inner peripheral portion 58c of the internally threaded portion 58A through the gap between the threaded rod 60 and the inner peripheral portion 58c of the internally threaded portion 58A. As shown in Fig. 5B, the internal thread portion 58A is consequently deformed to expand radially outward under the gas pressure of the compressed gas, and the inner peripheral portion 58c of the internal thread portion 58A is separated from the outer peripheral surface 60a of the threaded rod 60. Thus, the first shaft member 46A and the first motor 28 (see Fig. 2) is decoupled, and thus the first shaft element 46A can be displaced in the second direction. The first shaft element 46A is then displaced downward by the pressure difference between the first empty chamber 42a, into which the compressed air is introduced, and the second empty chamber 42b, which opens to the atmosphere, thereby bringing the first valve element 44 into contact with the first valve seat 40.

[0052] As described above, the flow control valve 22A of the present embodiment can also stop the liquid supply when a power failure occurs. (Third embodiment)

[0053] A flow control valve 22B of the present embodiment, which is shown in Fig. 6A, differs in an internal thread section 58B from the flow control valve 22 ( Fig. 3A). The flow control valve 22B will be described in detail below, but the same components in the configuration of the flow control valve 22B are assigned the same reference numerals as those in the configuration of the flow control valve 22 described with reference to Fig. 2 and Fig. 3A, and the detailed description thereof is omitted.

[0054] As in Fig. 6B, the internally threaded portion 58B of the present embodiment includes a plurality of blocks 58d circumferentially divided into a plurality of parts, and elastic members 61. Each block 58d is fan-shaped when viewed from above and has a screw groove in its inner peripheral portion 58c, as shown in FIG. The block 58d is arranged so that the inner peripheral portion 58c faces the outer peripheral surface 60a of the threaded rod 60. The block 58d is housed in the first receiving chamber 46c of the first piston portion 46b. Each block 58d can be displaced in the radial direction while being guided by the upper end wall 46d and the lower end wall 46e of the first receiving chamber 46c, as shown in Fig. 6A.

[0055] The elastic element 61 may, for example, consist of a coil spring. The elastic element 61 is arranged between the outer periphery of the block 58d and the side wall of the first receiving chamber 46c. The elastic element 61 presses the block 58d with its spring force toward the threaded rod 60. The screw groove of the block 58d engages with the thread of the threaded rod 60 when no gas pressure is applied to the first free chamber 42a. The female screw part 58B formed from a plurality of blocks 58d engages with the threaded rod 60 to control the rotational displacement of the first motor 28 (see Fig. 2) into a linear displacement, thereby displacing the first shaft element 46 in the second direction.

[0056] The flow control valve 22B of the present embodiment, configured as described above, operates as follows when a power failure occurs.

[0057] In case of a power failure, compressed gas is supplied through the gas flow path 33a to the first free chamber 42a. As in Fig. As shown in Figure 7, due to the pressure difference between the first free chamber 42a and the second free chamber 42b, a downward thrust is generated on the first shaft member 46. When a thrust force of a predetermined magnitude or more is generated, the screw groove of the block 58d attempts to slide over the thread of the threaded rod 60, and the block 58d is displaced radially outward against the elastic force of the elastic member 61. As a result, the female screw portion 58B is slidable and slides in the second direction with respect to the threaded rod 60. That is, the first shaft member 46 and the first motor 28 are decoupled.

[0058] Then, the first shaft member 46 is displaced downward, and the first valve element 44 supported by the first shaft member 46 is brought into contact with the first valve seat 40, thereby closing the first flow path 56. Therefore, the flow control valve 22B of the present embodiment can block the flow of the chemical solution even when a power failure occurs. (Fourth embodiment)

[0059] A flow control valve 22C of the present embodiment, which is shown in Fig. 8A is different from the flow control valve 22 ( Fig. 3A) by a first shaft member 46C and an internally threaded portion 58C. The flow control valve 22C will be described in detail below, but the same components in the configuration of the flow control valve 22C are assigned the same reference numerals as those in the configuration of the flow control valve 22 described with reference to the Fig. 2 and Fig. 3A, and the detailed description thereof is omitted.

[0060] As in Fig. As shown in Fig. 8B, the first shaft member 46C has a plurality of divided accommodating chambers 46g divided in the circumferential direction. The divided accommodating chambers 46g are arranged at equal intervals in the circumferential direction. In the illustrated example, the divided accommodating chambers 46g are arranged at 90° intervals in the circumferential direction. Each of the divided accommodating chambers 46g extends in the radial direction of the first shaft member 46C. As shown in Fig. As shown in Figure 8A, the ventilation opening 46f is provided below the divided accommodation chamber 46g. The ventilation opening 46f is located at the outer peripheral portion of the divided accommodation chamber 46g and allows communication between the divided accommodation chamber 46g and the second free chamber 42b. Therefore, the outer peripheral portion of the divided accommodation chamber 46g opens to the atmosphere via the second free chamber 42b.

[0061] The female screw portion 58C includes a plurality of blocks 58e and a plurality of elastic members 61C. In the illustrated example, the female screw portion 58C includes four blocks 58e. Each block 58e is housed in the divided accommodation chamber 46g. The block 58e has a sealing member 63 around its periphery. The sealing member 63 hermetically seals the gap between the divided accommodation chamber 46g and the block 58e. The block 58e is movable radially along the divided accommodation chamber 46g like a piston. A screw groove is formed on the inner peripheral portion 58c of the block 58e.

[0062] The elastic element 61C is arranged on the outer peripheral portion of the block 58e. The elastic element 61C urges the block 58e toward the threaded rod 60 located on the inner side with its elastic force. In a normal state in which no gas pressure is applied, the screw groove on the inner peripheral portion 58c of the block 58e engages the screw thread on the outer peripheral surface 60a of the threaded rod 60 due to the biasing force of the elastic element 61C.

[0063] The flow control valve 22C of the present embodiment, configured as described above, operates as follows when a power failure occurs.

[0064] When a power failure occurs, compressed gas is supplied through the gas flow path 33a to the first free chamber 42a. As shown in Fig. As shown in Figure 9, the compressed gas flows to the inner peripheral portion 58c of the block 58e. Due to the pressure difference between the first free chamber 42a and the outer peripheral portion (open to the atmosphere) of the divided accommodation chamber 46g, a radially outward thrust is generated at the block 58e. When the thrust exceeds a predetermined magnitude, the block 58e is displaced radially outward against the elastic force of the elastic member 61C, and the inner peripheral portion 58c of the block 58e is separated from the outer peripheral surface 60a of the threaded rod 60. This decouples the first shaft member 46C and the first motor 28.

[0065] Then, the first shaft member 46C is displaced downward, and the first valve element 44 supported by the first shaft member 46C is brought into contact with the first valve seat 40, thereby closing the first flow path 56. Therefore, the flow control valve 22C of the present embodiment can block the flow of the chemical solution even when a power failure occurs. (Fifth embodiment)

[0066] A flow control valve 22D of the present embodiment, which is shown in Fig. 10A is different from the flow control valve 22 of Fig. 3A by a first shaft member 46D and an internally threaded portion 58D. The flow control valve 22D will be described in detail below, but the same components in the configuration of the flow control valve 22D are assigned the same reference numerals as those in the configuration of the flow control valve 22 described with reference to the Fig. 2 and Fig. 3A, and the detailed description thereof is omitted.

[0067] As in Fig. 10A, the first shaft member 46D includes a first piston portion 80. In the illustrated example, the first piston portion 80 is connected to the first holder portion 46a (see Fig. 3A) which holds the first valve element 44. The first piston portion 80 can be formed as a separate body with a part that supports the first valve element 44 and a part that separates the first free chamber 42a and the second free chamber 42b. The first piston portion 80 is arranged within the first cylinder chamber 42 and divides the first cylinder chamber 42 in an airtight manner into an upper first free chamber 42a and a lower second free chamber 42b. Due to the pressure difference between the first free chamber 42a and the second free chamber 42b, a thrust force in the second direction is exerted on the first piston portion 80.

[0068] The first piston portion 80 has an engagement piece 82 at its upper part 80a, which protrudes upward along the second direction. The engagement piece 82 is rod-shaped with a constant outer diameter. At the upper end part of the engagement piece 82, an expanded diameter portion 82a is formed, the outer diameter of which is larger than that of the other portions. The engagement piece 82 is housed in an engagement portion 84 of the internally threaded portion 58D, which will be described later.

[0069] The internally threaded portion 58D is cylindrically shaped. The internally threaded portion 58D has an inner peripheral portion 58c at its central portion, on which a screw groove is formed, which is engaged with the threaded rod 60. The outer diameter of the internally threaded portion 58D may be smaller than the outer diameter of the first piston portion 80, and the outer peripheral portion of the internally threaded portion 58D may be separated from the inner wall 42c of the first cylinder chamber 42. The internally threaded portion 58D has a plurality of engaging portions 84 at a lower portion. The engaging portion 84 has a hole extending in the second direction and receiving the engaging piece 82 extending from the first piston portion 80. The inner diameter of the engaging portion 84 is larger than the outer diameter of the engaging piece 82.The engagement portion 84 has an annular projection 84a projecting inward at a predetermined position. The inner diameter of the annular projection 84a is smaller than the outer diameter of the expanded diameter portion 82a of the engagement piece 82. In the initial state, the expanded diameter portion 82a of the engagement piece 82 is located on and engaged by the annular projection 84a. Thus, the internally threaded portion 58D and the first piston portion 80 remain in a connected state.

[0070] The flow control valve 22D of the present embodiment, configured as described above, operates as follows when a power failure occurs.

[0071] As in Fig.10B, during a power failure, compressed gas is supplied through the gas flow path 33a to the first free chamber 42a, and a pressure difference is created between the first free chamber 42a and the second free chamber 42b. The first piston portion 80 generates downward thrust due to the pressure difference between the first free chamber 42a and the second free chamber 42b. When the thrust of the first piston portion 80 exceeds a predetermined value, the enlarged diameter portion 82a of the engaging piece 82 slides over the annular projection 84a of the engaging piece 84, as shown in the FIG., and the internally threaded portion 58D and the first piston portion 80 are uncoupled.

[0072] Thereafter, the first piston portion 80 is displaced downward, pushing the first valve element 44 downward. As a result, the first valve element 44 comes into contact with the first valve seat 40 to close the first flow path 56. As described above, the flow control valve 22D of the present embodiment can stop the supply of the chemical solution when a power failure occurs.

[0073] Although the above description was made with reference to the example in which the engaging piece 82 protrudes from the first piston portion 80, the present embodiment is not limited thereto. The engaging piece 82 may be configured to protrude downward from the internally threaded portion 58D toward the first piston portion 80. The engaging piece 82 may be formed separately from the internally threaded portion 58D and the first piston portion 80.

[0074] The present invention is not limited to the above disclosure, and various configurations can be adopted without departing from the gist of the present invention. The following supplementary notes are further disclosed with reference to the above disclosure. (Supplementary Note 1)

[0075] One aspect of the above invention is an electric valve unit (10) comprising a flow control valve (22, 22A, 22B, 22C, 22D), wherein the flow control valve (22, 22A, 22B, 22C, 22D) comprises a first valve chamber (38) communicating with an inlet flow path (54), a first valve seat (40) formed in the first valve chamber (38) and comprising an opening (56a) of a first flow path (56), a first valve element (44) facing the first valve seat (40) and forming a gap between the first valve element (44) and the first valve seat to adjust a flow rate of a chemical solution, and a first shaft element (46, 46A, 46B, 46C, 46D) displaced in a second direction while supporting the first valve element (44), and a first motor (28) which drives the first shaft element (46, 46A, 46B, 46C, 46D), and wherein the first shaft element (46, 46A, 46B, 46C,46D) generates a thrust force in the direction of the first valve seat (40) in the second direction by gas pressure, whereby the first valve element (44) is brought into contact with the first valve seat (40).

[0076] The electric valve unit described above can stop the supply of the chemical solution by moving the first valve element to the closed position by the gas pressure, even if a power failure occurs. (Supplementary Note 2)

[0077] The electric valve unit (10) described in Supplementary Note 1 may include a first screw mechanism (48) that converts the rotational displacement of the first motor (28) into a linear displacement in the second direction, and the first shaft elements (46, 46A, 46B, 46C, 46D) may be connected to the first motor (28) via the first screw mechanism (48). In the normal state, ie, without a power failure, such an electric valve unit can quantitatively control the first shaft element with the first screw mechanism. (Supplementary Note 3)

[0078] In the electric valve unit (10) described in Supplementary Note 2, the first screw mechanism (48) may include a threaded rod (60) coupled to the first motor (28) and an internally threaded portion (58, 58A, 58B, 58C) engaged with the threaded rod (60) and capable of increasing the diameter in the diameter-increasing direction. In such an electric valve unit, the diameter of the female screw part is increased, thereby enabling the displacement of the first shaft member in the second direction due to the gas pressure. (Supplementary Note 4)

[0079] In the electric valve unit (10) described in Supplementary Note 3, when gas pressure is applied, the internally threaded portions (58, 58B) and the threaded rod (60) can shift in a second direction due to the thrust of the first shaft members (46, 46B), thereby decoupling the first shaft members (46, 46B) and the first motor (28). With a simple device configuration, this electric valve unit can realize a structure capable of closing the first valve chamber with gas pressure. (Supplementary Note 5)

[0080] In the electric valve unit (10) described in Supplementary Note 3, the first shaft member (46A) may include a first receiving chamber (46c) that airtightly receives an outer peripheral portion of the internally threaded portion (58A), and the internally threaded portion (58A) may expand radially outward in a case where an inner peripheral portion (58c) in which a screw groove is formed is subjected to gas pressure, thereby decoupling the first shaft member (46A) and the first motor (28) from each other. This electric valve unit can expand the internally threaded portion using gas pressure, thus reliably decoupling the engagement state between the internally threaded portion and the screw rod when a power failure occurs. (Supplementary Note 6)

[0081] In the electric valve unit (10) described in Supplementary Note 3, the female screw portion (58B) may include a plurality of blocks (58d) divided in a circumferential direction and an elastic member (61) that biases the blocks (58d) toward the threaded rod (60). In a case where the gas pressure is applied, the blocks (58d) and the threaded rod (60) may slide in the second direction due to the thrust of the first shaft member (46B), thereby decoupling the first shaft member (46B) and the first motor (28) from each other. This electric valve unit can perform more stable operation because the decoupling between the female thread portion and the first motor can be adjusted by adjusting the biasing force of the elastic member. (Supplementary Note 7)

[0082] In the electric valve unit (10) described in Supplementary Note 3, the female screw part (58C) may include a plurality of blocks (58e) divided in a circumferential direction and an elastic member (61C) that biases the blocks (58e) toward the threaded rod (60), the first shaft member (46C) may include a divided receiving chamber (46g) that accommodates each of the blocks (58e) in a radially displaceable and airtight manner, and in a case where the gas pressure is applied, the blocks (58e) can be displaced in a direction away from the threaded rod (60) against the biasing force of the elastic member (61C), whereby the female threaded portion (58C) decouples the first shaft member (46C) and the first motor (28) from each other.This electric valve unit can perform more stable operation because the decoupling between the internal thread portion and the first motor can be adjusted by adjusting the preload force of the elastic member. (Supplementary Note 8)

[0083] In the electric valve unit (10) described in Supplementary Note 2, the first screw mechanism (48) may include a threaded rod (60) coupled to the first motor (28) and an internally threaded portion (58D) engaged with the threaded rod (60), and the first shaft member (46D) and the internal thread (58D) may be coupled via an engaging piece (82), and in a case where the gas pressure is applied, the engaging piece (82) can decouple the first shaft member (46D) and the internal thread (58D) from each other by the thrust of the first shaft member (46D). This electric valve unit can adjust the decoupling from the first motor with a simple configuration, thus reducing the manufacturing cost. (Supplementary Note 9)

[0084] The electric valve unit (10) described in Supplementary Note 1 may include a main body (26) having a first cylinder chamber (42) that accommodates the first shaft member (46, 46A, 46B, 46C, 46D) that is displaceable in the second direction, and a gas flow path member (33) that is disposed between the main body (26) and the first motor (28) and guides the gas pressure to the first cylinder chamber (42). The electric valve unit can reliably drive the first shaft member when a power failure occurs. (Supplementary Note 10)

[0085] The electric valve unit (10) described in any one of Supplementary Notes 1 to 9 may further include a suck-back valve (24) connected to a downstream side of the flow control valve (22, 22A, 22B). The electric valve unit can compactly implement the flow rate adjustment function and the suck-back function for the chemical solution. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 7175366 B1 [0002, 0003, 0004]

Claims

[1] An electric valve unit (10) comprising a flow control valve (22, 22A, 22B, 22C, 22D), the flow control valve (22, 22A, 22B, 22C, 22D) including: a first valve chamber (38) communicating with an inlet flow path (54), a first valve seat (40) formed in the first valve chamber (38) and comprising an opening (56a) of a first flow path (56), a first valve element (44) facing the first valve seat (40) and forming a gap between the first valve element (44) and the first valve seat (40) to adjust a flow rate of a chemical solution, a first shaft member (46, 46A, 46B, 46C, 46D) displaced in a second direction while supporting the first valve member (44), and a first motor (28) driving the first shaft member (46, 46A, 46B, 46C, 46D), and wherein the first shaft member (46, 46A, 46B, 46C, 46D) generates a thrust force toward the first valve seat (40) in the second direction by gas pressure, thereby bringing the first valve member (44) into contact with the first valve seat (40). [2] The electric valve unit (10) according to claim 1, further comprising a first screw mechanism (48) that converts the rotational displacement of the first motor (28) into a linear displacement in the second direction, wherein the first shaft member (46, 46A, 46B, 46C, 46D) is connected to the first motor (28) via the first screw mechanism (48). [3] The electric valve unit (10) according to claim 2, wherein the first screw mechanism (48) comprises a threaded rod (60) coupled to the first motor (28) and an internally threaded portion (58, 58A, 58B, 58C) engaged with the threaded rod (60) and capable of increasing the diameter of the internally threaded portion in a diameter-increasing direction. [4] The electric valve unit (10) according to claim 3, wherein, in a case where the gas pressure is applied, the female screw part (58, 58B) and the threaded rod (60) slide in the second direction due to the thrust of the first shaft member (46, 46B), thereby decoupling the first shaft member (46, 46B) and the first motor (28) from each other. [5] Electric valve unit (10) according to claim 3, wherein the first shaft member (46A) comprises a first receiving chamber (46c) which airtightly receives an outer peripheral portion of the internal thread portion (58A), and the internal thread portion (58A) expands radially outward in a case where an inner peripheral portion (58c) on which a screw groove is formed is subjected to the gas pressure, thereby decoupling the first shaft member (46A) and the first motor (28) from each other. [6] The electric valve unit (10) according to claim 3, wherein the internally threaded portion (58B) comprises a plurality of blocks (58d) divided in a circumferential direction, and an elastic member (61) that biases the blocks (58d) toward the screw rod (60), and in a case where the gas pressure is applied, the blocks (58d) and the screw rod (60) slide in the second direction due to the thrust of the first shaft member (46B), thereby decoupling the first shaft member (46B) and the first motor (28) from each other. [7] Electric valve unit (10) according to claim 3, wherein the female screw part (58C) comprises a plurality of blocks (58e) divided in a circumferential direction, and an elastic element (61C) which biases the blocks (58e) towards the threaded rod (60), the first shaft member (46C) comprises a split receiving chamber (46g) which receives each of the blocks (58e) in a radially displaceable and airtight manner, and in a case where the gas pressure is applied, the blocks (58e) are displaced against the biasing force of the elastic element (61C) in a direction away from the threaded rod (60), whereby the female screw part (58C) decouples the first shaft element (46C) and the first motor (28) from each other. [8] Electric valve unit (10) according to claim 2, wherein the first screw mechanism (48) a threaded rod (60) coupled to the first motor (28) and a female screw part (58D) engaging with the screw rod (60), the first shaft element (46D) and the female screw part (58D) are coupled via an engagement piece (82), and in a case where the gas pressure is applied, the engagement piece (82) decouples the first shaft member (46D) and the female screw part (58D) from each other due to the thrust of the first shaft member (46D). [9] Electric valve unit (10) according to claim 1, further comprising: a main body (26) including a first cylinder chamber (42) which accommodates the first shaft member (46, 46A, 46B, 46C, 46D) which is slidable in the second direction; and a gas flow path member (33) disposed between the main body (26) and the first motor (28) and directing the gas pressure to the first cylinder chamber (42). [10] The electric valve unit (10) according to any one of claims 1 to 9, further comprising a check valve (24) connected to a downstream side of the flow control valve (22, 22A, 22B).

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