Valves and diaphragm valves for semiconductor manufacturing equipment

Abstract

To provide a valve for a semiconductor manufacturing device and a diaphragm valve for the same that have excellent durability more than before, exert stable valve closing performance, are formed into a compact size, and facilitate performance evaluation.SOLUTION: In a valve for a semiconductor manufacturing device, an actuator part 3 for a high-pressure automatic valve including a force multiplication mechanism 8 for multiplying vertical load in an axial direction which is input from a piston 7 by utilizing a pitch difference of a threadably engaged body 16 comprising a threadably engaged screw or a helical structure is connected to a body part 2 including a valve element.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a valve used in an apparatus for a semiconductor manufacturing process, particularly to a valve for a semiconductor manufacturing apparatus provided with a force amplifier that increases the load for closing a flow path through which a high-pressure fluid flows, and its diaphragm valve.

Background Art

[0002] Conventionally, an automatic valve that operates an actuator by external pneumatic pressure and opens and closes a valve by utilizing the operation of a built-in piston or the like has been used for valves used in an apparatus for a semiconductor manufacturing process.

[0003] Particularly for this type of valve used for high-pressure gas, a strong clamping force is required to close the valve against the high-pressure gas flowing through the flow path and seal the flow path. Therefore, for high-pressure valves used in semiconductor manufacturing processes, in order to keep the valve in a closed state with a sufficient margin of load against the high-pressure gas flowing through the flow path, the load from a spring or the like is amplified by a mechanical force amplifier (such as a force multiplying mechanism) to generate a high load (clamping load) that does not yield to the gas pressure, and a force amplifier is provided to close the valve.

[0004] A force amplifier is generally a device that obtains a high output load by amplifying a compression load such as a spring using the principle of a lever. It uses a plane or inclined plane provided on a piston for a roller or ball, and has a structure combined with a cam that operates like a seesaw.

[0005] For example, as disclosed in FIG. 14 of Patent Document 1, a ball-type force multiplying mechanism is known in which a needle pushed down by a spring increases the input load by a steel ball or the like according to the angle ratio of an inclined surface of a cylindrical member. Also, as disclosed in FIG. 1 of Patent Document 1 and the like, a ball-type force multiplying mechanism is known in which the output load is increased according to the angle ratio of an inclined surface of a plate connecting a steel ball and a shaft and a tapered surface of a piston for the input load of a spring.

[0006] In addition, as disclosed in Figure 11 of Patent Document 2, a cam-type power assist mechanism is known that utilizes the principle of levers and amplifies the compressive load of a spring by transmitting it through a substantially L-shaped cam. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2012-37048 [Patent Document 2] International Publication No. 2015 / 020209 [Overview of the project] [Problems that the invention aims to solve]

[0008] However, the ball-type power assist mechanism described in Patent Document 1 has a structure in which the balls slide when pressed, so friction occurs because the direction of movement of the balls and the direction in which the balls try to rotate are different. Friction also occurs because multiple balls do not move in a coordinated manner simultaneously. As a result of this friction, problems arose such as increased transmission loss and variations in the transmitted output load. Furthermore, the load transmitted by the sliding of the balls varied, causing the tightening load when the valve closed to change, resulting in a different output load than that specified in the design. In addition, the variations in load and friction caused wear to concentrate on specific parts, leading to durability problems.

[0009] Furthermore, in the cam-type power assist mechanism described in Patent Document 2, the structure involves a sliding mechanism at the point of application of a high load due to the lever principle. Because it slides in line contact with the mating part, there is significant transmission loss due to friction. The cam's dimensions change rapidly due to wear caused by the concentration of load, reducing the multiplier and thus decreasing the output load. Furthermore, because the conversion ratio fluctuates curvilinearly depending on the angle at which the cam is tilted, it is difficult to determine whether the output load initially designed is being generated at the piston position where the valve is closed. This is difficult to predict during the design phase because it cannot be determined without actually building a prototype and conducting performance tests.

[0010] When a high conversion ratio is required, it is necessary to design a large ratio between the distance from the fulcrum to the point of force application and the distance from the fulcrum to the point of application, as described by the lever principle. However, increasing this ratio makes the cam itself longer and larger, and in order to secure the operating stroke of the actuator, the actuator must be made larger, resulting in a larger valve.

[0011] In both structures, the direction of load application and the change in conversion ratio between the open and closed valve states are not linear. As a result, it is difficult to determine how much the output load (tightening load) changes when the valve closed position changes. This leads to inconsistent and unstable tightening loads due to the complex mechanism, and strong wear can easily reduce the tightening load, degrading the valve closing performance from the initial design and shortening the valve's product life.

[0012] Furthermore, structural issues with the power booster built into high-pressure automatic valves tend to increase the product size. If the power booster cannot be enlarged due to the demand for smaller valves, it becomes impossible to secure a sufficient stroke, resulting in insufficient valve closing performance.

[0013] Therefore, there was a need to miniaturize valves for high-pressure fluids, develop a power amplification mechanism that facilitates the calculation and design of the amplification amount required for the power amplification mechanism that closes the flow path of high-pressure fluids, and develop a valve for semiconductor manufacturing equipment equipped with this power amplification mechanism.

[0014] This invention was developed to solve the problems of the past, and its objective is to provide a valve and diaphragm valve for semiconductor manufacturing equipment that are more durable and stable in valve closing performance than conventional valves, are more compact, and are easier to evaluate in terms of performance. [Means for solving the problem]

[0015] To achieve the above objective, the invention according to claim 1 is: This is a high-pressure automatic valve actuator for semiconductor manufacturing equipment. It connects a piston that transmits the vertical load generated along the axial direction of the actuator to a rotor arranged coaxially with the piston to convert the vertical load into rotational torque. A force amplification mechanism that uses the pitch difference of a screw or helical structure connected to the rotor to increase the force converts the rotational torque into vertical load as axial force. The rotor converts the vertical load of a push rod, which is arranged coaxially with the piston, into rotational torque via a helical groove provided in a cylindrical rotating body.

[0018] Claim 2 The invention according to claim is a valve for a semiconductor manufacturing apparatus that can maintain a valve closed state against a back pressure from a flow path applied in a valve closing direction exceeding an axial force generated by a boosting mechanism when the valve is closed by utilizing the self-locking phenomenon of a screw.

[0019] Claim 3 The invention according to claim uses the axial force generated by the rotation of a screw to directly or indirectly The actuator is connected to the actuator push down a diaphragm provided in a body to open and close a valve, which is a diaphragm valve for a semiconductor manufacturing apparatus.

[0020] Claim 4 The invention according to claim is a valve for a semiconductor manufacturing apparatus that arbitrarily sets the pitch angle of a groove of a screwed body or the amount of rotation of a rotor to appropriately set the opening and closing stroke amount of a valve mechanism and the tightening load of the valve mechanism.

Effect of the Invention

[0023] Claim 1 According to the invention according to claim, a piston that transmits a vertical load generated along the axial direction of an actuator and a rotor arranged coaxially with the piston are connected to convert the vertical load into a rotational torque, and a boosting mechanism that boosts using a pitch difference of a screwed body having a screwed state or a spiral structure connected to the rotor converts the rotational torque into an axial force as a vertical load. By doing so, the input load from the piston is once converted into a rotational motion, and then the rotational torque generated by the rotational motion is converted into a propulsive force and output as an amplified vertical load to generate a tightening load for closing the valve. In particular, according to the present invention, by adopting a boosting mechanism that converts and utilizes an input load in a rotational direction, it is possible to provide a high-pressure gas valve for semiconductors that is more compact and has a longer lifespan compared to conventional products.

[0024] In addition, by using the pitch difference to generate a vertical load, the output load can be made uniform, and a stable tightening load can be generated. Moreover, since the load does not concentrate on a specific part of the movable part, wear can be reduced and durability can be enhanced.

[0025] Also, because the pitch difference is utilized, the calculation of the output load is easy, and the conversion magnification of the output load can be freely designed. Furthermore, since the necessary tightening load can be generated by using the pitch difference, there is no need to enlarge the force amplifier mechanism to obtain the required load, and the compactification can be achieved.

[0026] The rotor is By converting the vertical load of a push rod provided coaxially with the piston through a spiral groove provided in a cylindrical rotating body into rotational torque, compared with the conventional cam-type or ball-type force amplifier mechanisms, the force amplifier mechanism can be incorporated into the actuator without complicating the structure, and the vertical load can be reliably and highly accurately converted into rotational torque. Therefore, there is no need to enlarge the force amplifier mechanism to increase the conversion magnification of the vertical load and the rotational torque, etc., so the compactification of the actuator and the valve can be achieved.

[0027] Claim 2 According to the invention according to the claim, by utilizing the self-locking phenomenon of the screw and maintaining the valve closed state against the reverse pressure from the flow path applied in the valve closing direction exceeding the axial force generated by the force amplifier mechanism when the valve is closed, even if excessive internal pressure is generated in the valve closed state, the screw will not reverse and move in the valve opening direction, so a stable valve closed state can be maintained and the safety of the valve product can be enhanced.

[0028] In other words, in a typical diaphragm valve, if an accident occurs that results in a reaction force greater than the designed valve closing load, the valve can easily open. However, in this invention, like a worm gear, self-locking occurs due to high frictional force against axial loads that are nearly perpendicular to the screw threads. Therefore, the screw will not reverse unless there is a reaction force that far exceeds the tightening load generated by the valve closing operation. As a result, even if excessive internal pressure is applied to the valve due to an accident, the risk of it opening unintentionally is reduced, making it possible to provide a safer valve product.

[0029] Claim 3 According to the invention, the axial force generated by the rotation of the screw is used directly or indirectly Connected to the actuator By pressing a diaphragm located inside the body to open and close the valve, we can provide a diaphragm valve for semiconductor manufacturing equipment that offers improved durability and can maintain a stable valve closed state. Furthermore, by making the actuator more compact without increasing the valve diameter, a large number of valves can be arranged in a space-saving manner, thus contributing to the compactness of semiconductor manufacturing equipment.

[0030] Claim 4 According to the invention, a linear output load can be obtained by first converting the load generated by the spring into rotational motion, and then converting the torque generated by the rotation back into the axial force (thrust force) of a structurally directly connected screw. Furthermore, the conversion ratio of the output load can be freely designed simply by designing the rotation diameter and the feed pitch of the screw threads. In addition, the stroke amount for opening and closing the valve can be individually designed by setting the piston stroke and the rotation angle of the rotor, making it possible to intuitively calculate the amount of movement of the parts necessary for valve design. [Brief explanation of the drawing]

[0031] [Figure 1]This is a cross-sectional view of a valve for semiconductor manufacturing equipment according to one embodiment of the present invention, showing the valve in the open state. [Figure 2] This is a cross-sectional view of the valve in the closed position. [Figure 3] These are half cross-sectional views of the valve's power amplification mechanism; (a) is a half cross-sectional view of the valve in the open state, and (b) is a half cross-sectional view of the valve in the closed state. [Figure 4] This is a disassembled perspective view of the power amplification mechanism. [Modes for carrying out the invention]

[0032] Embodiments of the present invention will be described in detail below. Figure 1 is a cross-sectional view of a valve for semiconductor manufacturing equipment according to one embodiment of the present invention in the open state. Figure 2 is a cross-sectional view of the valve in the closed state. Figure 3 is a half cross-sectional view of the power amplification mechanism of the valve, where (a) is a half cross-sectional view of the valve in the open state and (b) is a half cross-sectional view of the valve in the closed state. Figure 4 is an exploded perspective view of the power amplification mechanism of the valve.

[0033] An embodiment of the present invention provides a valve for semiconductor manufacturing equipment (diaphragm valve for semiconductor manufacturing equipment) which is installed in a flow path of semiconductor manufacturing equipment and used to block or open the flow path of high-pressure fluid within the flow path.

[0034] The valve for semiconductor manufacturing equipment in this example is equipped with an actuator 3 for high-pressure automatic valves, and is an automatic valve that opens and closes the valve body (diaphragm) 23 by supplying air from an external source. When air is supplied from the air port 4, the valve is in the open state, and when the air supply is stopped, the valve is in the closed state. It is a so-called normally closed (NC type) automatic valve. In this example, the explanation assumes a normally closed structure, but by swapping the structure of the air-driven part and the spring-driven part, it can also be applied to normally open (NO type) products, which have the opposite operation type, as the only difference is whether the load source is air or spring.

[0035] As shown in Figures 1 and 2, the valve for semiconductor manufacturing equipment is constructed by connecting a body (body section) 2 having a valve body (diaphragm) 23 and an actuator (actuator section) 3 that incorporates a power boosting mechanism 8.

[0036] (Regarding Body Section 2) The flow path 21 within the body section 2 is configured such that a diaphragm piece 24, supported by a diaphragm retainer 25, is pushed down toward the valve seat 22, pressing against the diaphragm 23. This causes the diaphragm 23 to be pushed down and come into close contact with the valve seat 22, thereby blocking the flow path 21 of high-pressure fluid.

[0037] (Regarding actuator unit 3) The actuator unit 3 consists of a base body 33, a cylinder body 32, and a cap body 31. The base body 33 and the cylinder body 32 are screwed together by female and male threads, and the cylinder body 32 and the cap body 31 are screwed together by female and male threads. The base body 33 is prevented from rotating by a set screw (not shown), and the male thread of the base body 33 is screwed into the female thread of the body 2, thereby connecting the actuator 3 and the body 2 and forming the valve body.

[0038] The actuator 3 contains a spring (elastic member) 5 that generates a load to seal the valve and a spring receiver 6 that transmits the elastic force of the spring 5. Below the piston 7 that transmits the input load from the spring receiver 6, there is a force amplification mechanism 8 that amplifies the axial vertical load of the actuator 3 input from the piston 7.

[0039] (Regarding the power amplification mechanism 8) As shown in Figure 4, the force amplification mechanism 8 comprises a push rod (pressing member) 11, a rotor 12, and a guide member (guide sleeve) 13. The force amplification mechanism 8 is compactly housed within a predetermined space in the base body 33 and amplifies the input load from the piston 7. In this example, the force amplification mechanism 8 transmits a vertical load generated along the axial direction of the actuator 3 by utilizing the pitch difference of a screw-type or helical structure screw assembly 16 connected to a rotor 12 arranged coaxially with the piston 7. In other words, the input load from the piston is first converted into rotational motion, and the resulting rotational torque propels the screw assembly 16. The axial force (propulsive force) of this screw assembly 16 is then used as the output load (vertical load), generating a tightening load that pushes down the valve body (diaphragm) 23.

[0040] (Regarding pushrod 11) The push rod 11 has an elongated pin shape with a length approximately equal to the diameter of the piston 7, and rotatable bushings 14 are attached to both ends of the push rod 11. The push rod 11 is inserted into the helical portion 18 of the rotor 12 and the guide groove 13a of the guide member 13 so as to be able to move up and down, and is mounted by being inserted into the through hole 7a formed in the extension portion 7A of the piston 7. As a result, the push rod 11 moves up and down together with the piston 7, transmitting the vertical load input from the piston 7 to the rotor 12.

[0041] (Regarding rotor 12) The rotor 12 converts the vertical motion (linear motion) of the push rod 11 into rotational motion, propels the screw assembly 16, and transmits the vertical load via the output unit 17 to generate a clamping load on the valve body 23.

[0042] The rotor (cylindrical rotating body) 12 is hollow and has a roughly cylindrical appearance, with a pair of spiral grooves (spiral sections) 18 on its outer circumference. The lower end of the rotating body 12 is connected to a screw or a screw assembly 16 having a spiral structure. The angle (pitch angle) of the spiral sections 18 is not particularly limited, but in this example, it can be set appropriately between 40° and 60°. A 45° angle for the spiral sections 18 is preferable because it makes it easier to calculate the relationship between the amount of rotation of the rotor 12 and the thrust force during the design phase. When the push rod 11, which is inserted through the helical portion 18, moves up and down due to the vertical load from the piston 7, the vertical load from the push rod 11 via the helical portion 18 generates a rotational force in the rotor 12, so the rotor 12 rotates in conjunction with the up and down movement of the push rod 11. In this way, the axial vertical load input from the piston can be converted into rotational motion to generate rotational torque. By connecting the screw assembly 16 to the lower end of the rotor 12 and integrating them, high-precision rotational torque can be generated.

[0043] (Regarding screw assembly 16) The screw assembly 16 has a helical structure 16a on its outer surface, which is screwed into the female thread portion 33a of the base body 33 of the actuator 3, and the lower end of the screw assembly 16 is connected to the output section 17. The helical structure 16a is not particularly limited, but can be formed by a screw (threaded portion) having a male thread, and the male screw is screwed into the female threaded portion 33a of the base body and fixed in a screwed state. The helical structure 16a may also be formed by a helical groove such as a screw thread by a notch.

[0044] Since the screw assembly 16 is fixed to the base body 33 in a screwed state, it can exhibit a self-locking function. When subjected to an axial load that is nearly perpendicular to the threads of the screw assembly 16, self-locking is achieved by a high frictional force, so the screw 16a will not reverse unless there is a reaction force that far exceeds the tightening load generated by the valve closing operation.

[0045] The screw threads of the helical structure 16a may be multi-threaded, and the pitch angle of the screw threads can be set appropriately according to the embodiment. It can be set to a different angle from the pitch angle of the helical portion 18, and by setting the screw threads of the helical structure 16a to a different pitch angle, it can be used as a pitch difference, and the amount of threaded assembly 16 can be set appropriately. Therefore, for example, when increasing the conversion ratio between vertical load and rotational torque, the amount of feed required for the clamping load (output load) can be determined by adjusting a predetermined pitch difference or rotation amount. This allows for adjustment without increasing the size of each component of the power amplification mechanism, and the power amplification mechanism 8 can be compactly housed inside the actuator 3.

[0046] (Regarding output unit 17) The tip of the output section (output shaft) 17 is in contact with the diaphragm piece 24 and is designed to be able to press down the diaphragm 23. An O-ring 10 is also attached to the output shaft 17. When the rotor 12 rotates, rotational torque is transmitted to the screw body 16, and the rotation of the rotor 12 generates a thrust force in the screw body 16, which becomes the axial force of the vertical load on the screw body 16. As a result, the output part 17 of the screw body 16 is pushed in a direction that presses against the diaphragm 23, generating a tightening load that seals the valve body (diaphragm) 23 and seals the valve. In this example, the output unit indirectly presses the diaphragm via a diaphragm piece, but the output unit may also directly press down on the diaphragm.

[0047] (Regarding bearing component 9) A bearing member 9 is placed between the rotor 12 and the base body 33 to smooth the rotational motion of the rotor 12 and reduce friction between the rotor 12 and the base body 33.

[0048] (Regarding guide member 13) The guide member (guide sleeve) 13 has a hollow cylindrical appearance and has a vertical guide groove 13a. The push rod 11 is inserted into this guide groove 13a, and the linear motion of the push rod 11 is guided with high precision by the guide groove 13a which is in the same axial direction as the up and down movement of the piston 7.

[0049] (Regarding valve operation) Next, we will explain the operation of the valve (diaphragm valve) and the operation and function of the power amplification mechanism. Figure 3(a) shows the valve in the open state, and Figure 3(b) shows the valve in the closed state.

[0050] When the air supply to the air port 4 from the outside is stopped, the elastic force of the spring 5 becomes greater than the internal pressure of the air chamber, and the spring support 6 is pushed down vertically by the elastic force of the spring 5. The vertical load of the spring 5 pushes down the piston 7 connected to the spring support 6, and the vertical load of the spring 5 is transmitted to the piston 7.

[0051] As the piston 7 descends, the push rod 11 inserted into the through hole 7a of the piston 7 moves linearly (vertically) along the guide groove 13a of the guide member 13 in the same direction as the axial direction of the actuator 3 (arrow A).

[0052] At this time, the push rod 11 descends while pressing against the helical portion 18 of the rotor 12, causing the rotor 12 to rotate clockwise (arrow B). The rotational motion of the rotor 12 generates rotational torque, causing the screw assembly 16 connected to the rotor 12 to rotate (arrow C), and a thrust force acts according to the pitch angle of the screw threads 16a of the screw assembly 16, causing the screw assembly 16 to descend.

[0053] The output section 17 connected to the screw assembly 16 descends (arrow D), pressing against the diaphragm piece 24 that abuts against the tip of the output section 17. The tightening load is transmitted from the diaphragm piece 24, pushing down the valve body (diaphragm) 23, causing the valve body 23 to come into close contact with the valve seat 22, resulting in a closed valve state.

[0054] The thrust of the screw assembly 16 utilizes the pitch difference between the pitch angle of the helical portion 18 and the pitch angle of the screw assembly 16, causing the screw assembly 16 to move. Furthermore, since the actuator moves linearly in the axial direction, and a linear axial force is applied, a linear load is generated to create the tightening load necessary to close the valve, thereby sealing the valve.

[0055] Therefore, by connecting the actuator section 3 of a high-pressure automatic valve, which is equipped with a force amplification mechanism 8 that amplifies the axial vertical load input from the piston 7 by utilizing the pitch difference of a screw-type assembly 16 consisting of a screw or helical structure 16a, with the body section 2 having a valve body 23, it is possible to generate a tightening load that causes the valve body 23 to be in close contact with the valve seat 22 by the thrust force of the screw-type assembly 16, whose load has been amplified by utilizing the pitch difference. Furthermore, since the output load is a linear clamping load and a load in the direction of movement (linear load), it transmits a linear load and generates a clamping load. Therefore, it can generate a stable clamping load by reducing transmission loss and load variation of the input load compared to conventional ball-type or cam-type force amplification mechanisms. In addition, since the output load does not change even after the valve is installed, stable valve closing performance can be achieved.

[0056] Furthermore, because it utilizes the pitch difference, the output load can be easily calculated, allowing for easy calculation of the output load from the design stage and enabling flexible design of the conversion ratio. In particular, since it is possible to increase the opening and closing stroke of the actuator valve or change the clamping load simply by changing the amount of rotation of the rotating parts, there is no need to design the valve diameter to be large. Therefore, it is possible to provide a space-saving product that is suitable for applications where many valves are arranged in a given area. In other words, the conversion factor of the output load can be calculated and freely designed simply by designing the screw rotation diameter and thread feed pitch. Furthermore, by setting the piston stroke and rotor rotation angle, the stroke amount for opening and closing the valve can also be individually designed, making it possible to intuitively calculate the amount of movement of the parts necessary for valve design.

[0057] Furthermore, because the necessary clamping load is generated by utilizing the pitch difference, the load does not concentrate on specific parts of the movable member, thereby reducing wear on the movable member and increasing its durability. In other words, compared to conventional force-amplifying mechanisms that use balls or rollers as movable members, the contact area of ​​the movable member is not point contact or line contact, but rather the wide contact surface of the threaded portion distributes the load. As a result, the surface pressure at the contact points is reduced, which reduces excessive friction and wear, improving durability and extending the product life.

[0058] Furthermore, since the required clamping load can be generated by utilizing the pitch difference, it is not necessary to enlarge the force amplification mechanism to obtain the required load, allowing for a more compact design.

[0059] In this embodiment, the rotor 12 converts the vertical load of the push rod 11, which is mounted coaxially with the piston via a helical groove (helical section) 18, into rotational torque. Compared to conventional cam-type and ball-type power amplification mechanisms, this allows the power amplification mechanism 8 to be built into the actuator without complicating its structure, and enables the vertical load to be converted into rotational torque reliably and with high precision. Therefore, since there is no need to enlarge the power amplification mechanism to increase the conversion ratio between vertical load and rotational torque, the actuator and valve can be made more compact.

[0060] In this embodiment, the screwed body 16 increases the axial load input from the piston by utilizing the pitch difference of the screwed body 16 while it is screwed in place. Because the screwed body 16 is screwed in place with the female thread portion 33a of the base body 33, the engagement of the threads 16a of the screwed body 16 and the female thread portion 33a of the base body 33 utilizes a self-locking phenomenon to maintain the valve closed state against the reverse pressure from the flow path acting in the valve closing direction that exceeds the axial force generated by the force amplification mechanism 8 when the valve is closed.

[0061] In conventional diaphragm valves, if a reaction force greater than the valve closing load designed occurs in the internal flow path while the valve is closed, the diaphragm is pushed back and the valve opens. However, in the present invention, like a worm gear, self-locking occurs due to high frictional force against axial loads that are nearly perpendicular to the screw threads. Therefore, unless there is a reaction force that far exceeds the tightening load generated by the valve closing operation, the screw will not reverse, and the valve can be kept closed. Therefore, even if excessive internal pressure is applied to the valve, there is no risk of it opening unintentionally, making it possible to provide valve products that are safer than conventional ones.

[0062] According to this embodiment, by using the axial force generated by the rotation of a screw to directly or indirectly press down on a diaphragm 23 provided inside the body 2 to open and close the valve, it is possible to provide a diaphragm valve for semiconductor manufacturing equipment that has improved durability and can maintain a stable valve closed state. Furthermore, by making the actuator more compact without increasing the valve diameter, a large number of valves can be arranged in a space-saving manner, thus contributing to the compactness of semiconductor manufacturing equipment.

[0063] Therefore, in this embodiment, a linear output load can be obtained by first converting the load generated by the spring into rotational motion, and then converting the torque generated by the rotation back into the axial force (thrust force) of a structurally directly connected screw. Furthermore, the conversion ratio of the output load can be freely designed simply by designing the rotation diameter and the feed pitch of the screw threads. In addition, the stroke amount for opening and closing the valve can be individually designed by setting the piston stroke and the rotation angle of the rotor, making it possible to intuitively calculate the amount of movement of the parts necessary for valve design. [Examples]

[0064] Next, an embodiment (design example) of the power amplification mechanism according to the present invention will be described. This is an example of an embodiment of the present invention and does not limit the present invention.

[0065] • Design of the threaded portion of a screw assembly When designing the power amplification mechanism 8 according to the present invention, there is a risk that the diaphragm 23 will be pushed back by the repulsive force of the high-pressure gas when the valve is tightened with the final stage screw, causing the screw 16a to break. Therefore, the strength of the screw of the screw assembly 16 should be considered first. The axial force when tightening metric screws made of common metal materials is large. According to technical data from Tohnichi Manufacturing Co., Ltd., for screws made of common steel, the force is 2980N for M5 size and 12200N for M10 size. Therefore, common metal materials have the strength to withstand very large loads.

[0066] If we assume that the piston thrust required to close the valve body (diaphragm) 23 against high-pressure gas is 2000-3000N (for example, in the case of a valve with a valve closing capacity of about 20MPa), then as long as the size is at least equivalent to M5 and has sufficient margin, and the thread design is such that the required axial force can be output, there will be no problem in terms of strength.

[0067] Regarding rotor design Next, we will consider the design of the rotor when the actuator stroke required to open and close the valve is 0.5 mm. The theoretical diameter through which force is transmitted when the rotor 12 is pushed down by the piston 7 is defined as the "design diameter," and is determined according to the target product size and the size of the piston-related components. In this case, if there are no design constraints on size or stroke length, the helical groove (helical section) 18 of the rotor 12 is set to a pitch angle of 45°. In this case, it is convenient from a design perspective to convert the vertical motion from the spring into rotational motion at a 1:1 ratio, and even when considering mechanical losses, it is well-balanced and convenient.

[0068] When the pitch angle of the helical section 18 is 45°, the vertical stroke of the piston and the apparent rotation of the rotor as seen from above are equal in ratio (1:1) as the distance traveled along the circumference of the design diameter. Therefore, the required rotation angle can be calculated by using the rotational distance along the circumference and the ratio of this distance to the total circumference (diameter × π) obtained from the design diameter.

[0069] In this example, the helical section 18 is composed of two symmetrical grooves, so it can be considered equivalent to a double-start screw. If the design diameter is 28 mm, the feed pitch of the helical groove with a screw pitch angle of 45° is equivalent to the circumference ÷ 2, so (28 × π) ÷ 2 ≈ 44 mm. In other words, the helical groove in this case can be likened to a screw with a thread that feeds 44 mm per rotation. In the above calculation example, the rotation angle θ of the rotor 12 when the piston has reached its full stroke (piston stroke + rotor opening / closing stroke) can be expressed by the following formula. θ = 360° ÷ Feed pitch 44 mm × Full stroke length

[0070] In this case, assuming the piston stroke is 5 mm and the stroke of the screw at the end of the rotor (valve opening / closing stroke) is 0.5 mm, then θ = 360° ÷ 44 × (5 + 0.5) = 45°. In other words, the rotor rotates 45° due to the full stroke of the piston, which is 5.5 mm. Therefore, the screw 16a at the lower tip of the rotor 12 should be designed with a pitch that results in a stroke of 0.5 mm when the rotor rotates 45°.

[0071] Next, we design the screw at the tip of the rotor (screw 16a of the screw assembly 16). The screw pitch P can be calculated using the following formula. P = 360° ÷ 45° × stroke (0.5) = 4 mm Here, for example, if the screw is a double-start screw, the lead will be 4mm, so the screw pitch P will be 4 ÷ 2 = 2mm. In other words, in terms of strength, if you design a sufficiently large screw of M5 size or larger, and design a screw with a thread pitch P of 4mm (2mm in the case of a double-start screw), the stroke amount will be 0.5mm.

[0072] • Regarding the design of springs Finally, we determine the load of spring 5 required to drive the designed power amplification mechanism. An example of this calculation is shown below. Generally, the relationship between torque and the axial force of a screw is expressed by the following equation 1. Fo = T ÷ (k×D2) (Formula 1) Fo[N] The final output load (axial force) T [N·m] Rotor Torque D2[m] Rotor screw diameter k is the torque coefficient (generally 0.15 to 0.2; in this example, it is 0.2).

[0073] The torque of the rotor generated by the thrust of piston 7 is expressed by the following equation 2. T = (D1÷2) × Fi × L (Formula 2) Fi[N] Piston load (initial spring deflection load) D1[m] Rotor calculation diameter L conversion ratio (in this example, the pitch angle is 45°, so it's 1)

[0074] From Equations 1 and 2, the axial force output at the final stage (the load required to close the valve) is: Fo = (D1 ÷ 2) × Fi × L ÷ (k × D2) This is the result.

[0075] The required spring load Fi can be found by rearranging the above formula: Fi = Fo ÷ (D1 ÷ 2) × (k × D2) ÷ L This can be calculated using the following formula.

[0076] Therefore, assuming that the load Fo required to close the valve is 2500N, and that the calculated diameter of the rotor D1 = 0.028m and the screw diameter of the rotor's screw assembly D2 = 0.010m, Fi =2500÷(0.028÷2)×(0.2×0.01)÷1 ≒360N Therefore, the load (elastic force) of spring 5 should be designed using the calculated value of 360N plus a margin for losses due to friction, etc., as the initial deflection load.

[0077] As shown in the above embodiment, the structure according to the present invention has a simple force transmission method, so the performance when the valve is closed can be estimated with simple calculations, allowing for accurate consideration at the design stage. In addition, the present invention simplifies the structure, allows for compactness, and extends product life by reducing mechanical variations and wear due to strong friction.

[0078] Although embodiments of the present invention have been described in detail above, the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention as described in the claims of the present invention.

[0079] Although the above embodiment describes an NC type automatic valve, it is also applicable to normally open (NO type) automatic valves. By swapping the structures of the air-driven and spring-driven parts, the only difference in operation type is whether the load source is air or spring. Therefore, in the NO type automatic valve, the valve can be closed by pressing the piston with air supply, achieving the same effects as in the above embodiment.

[0080] Furthermore, although the above embodiment transmits the vertical load by pistons, there is no limit to the number of pistons, and it may be configured with two or more pistons. [Explanation of Symbols]

[0081] 2. Body (Body section) 3. Actuator (actuator unit) 4 Airport 5. Spring (elastic component) 6 Spring receiver 7 pistons 7A Extension part 7a Through hole 8. Power amplification mechanism 9 Bearing components 10 O-rings 11. Push rod (pressing member) 12. Rotor (Cylindrical Rotating Body) 13 Guide member (guide sleeve) 13a Guide groove 14 Bush 16 Screw-type assembly 16a Spiral structure (screw) 17 Output section (output shaft) 18 Spiral part 21 Flow channels 22 valve seat 23. Valve body (diaphragm) 24 diaphragm pieces 25 Diaphragm retainer 31 Cap Body 32-Cylinder Body 33 Base Body 33a Female thread section

Claims

1. An actuator for a high-pressure automatic valve, comprising a piston that transmits a vertical load generated along the axial direction of the actuator, a rotor arranged coaxially with the piston, which are connected to convert the vertical load into rotational torque, and a force amplification mechanism that amplifies the force by utilizing the pitch difference of a screw or helical structure connected to the rotor, thereby converting the rotational torque into a vertical load as axial force, wherein the rotor converts the vertical load of a push rod arranged coaxially with the piston into rotational torque via a helical groove provided in a cylindrical rotating body.

2. The valve for semiconductor manufacturing equipment according to Claim 1, wherein the valve can maintain a closed state against a back pressure from the flow path acting in the valve closing direction that exceeds the axial force generated by the force amplification mechanism when the valve is closed, by utilizing the self-locking phenomenon of the screw.

3. The diaphragm valve for semiconductor manufacturing equipment according to claim 1, wherein the valve is opened and closed by directly or indirectly pressing a diaphragm provided in a body connected to the actuator using the axial force generated by the rotation of the screw.

4. The valve for semiconductor manufacturing equipment according to Claim 1, wherein the pitch angle of the groove of the screw assembly or the amount of rotation of the rotor is arbitrarily set to appropriately set the opening and closing stroke amount of the valve mechanism and the tightening load of the valve mechanism.

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