Actuator and valve device

Abstract

This actuator comprises: a cylinder; a lower piston housed in the cylinder; a piston rod; an upper piston housed in the cylinder; a partition part fixed in the cylinder in a manner as to be positioned between the lower piston and the upper piston; a first pressure chamber formed by the lower piston, the bottom wall of the cylinder, and the circumferential wall of the cylinder; a second pressure chamber formed by the upper piston, the partition part, and the circumferential wall of the cylinder; a first tube which connects the first pressure chamber and a first solenoid valve; and a second tube which is provided in parallel with the first tube and which connects the second pressure chamber and a second solenoid valve.

Description

Actuators and valve devices

[0001] The present invention relates to an actuator and a valve device.

[0002] JP2017-44290A discloses a valve device that opens a flow path in a valve body by supplying air to two pressure chambers of an actuator.

[0003] However, in the valve device described in JP2017-44290A, the length of one air flow path supplying air from the air supply source to one pressure chamber is different from the length of the other air flow path supplying air from the air supply source to the other pressure chamber, resulting in a time difference in the supply of air from the air supply source to the two pressure chambers, and reducing the responsiveness of the valve device when opening and closing the flow paths in the valve body.

[0004] The present invention has been made in view of this problem, and has an object to provide an actuator and a valve device that can improve responsiveness.

[0005] According to one aspect of the present invention, there is provided an actuator for use in a valve device, the actuator comprising: a cylinder; a first piston housed within the cylinder so as to be slidable along an inner circumferential surface of the cylinder; a piston rod provided so as to protrude to one side from the first piston; a second piston provided on the other side of the first piston and housed within the cylinder so as to be slidable along the inner circumferential surface of the cylinder; a partition portion fixed within the cylinder so as to be located between the first piston and the second piston; a first pressure chamber formed by the first piston, the piston rod, a bottom wall of the cylinder, and a circumferential wall of the cylinder; a second pressure chamber formed by the second piston, the partition portion, and the circumferential wall of the cylinder; a first fluid flow path communicating the first pressure chamber with a fluid supply source; and a second fluid flow path communicating the second pressure chamber with the fluid supply source, wherein the length from the fluid supply source to the second pressure chamber is the same as the length of the first fluid flow path from the fluid supply source to the first pressure chamber.

[0006] According to this aspect, the responsiveness of the valve device can be improved.

[0007] FIG. 1 is a cross-sectional view showing a valve device according to this embodiment. FIG. 2A is a graph showing an example of the relationship between the operating time and air pressure when the valve is opened for the valve device according to this embodiment and a conventional valve device. FIG. 2B is a graph showing an example of the relationship between the operating time and air pressure when the valve is closed for the valve device according to this embodiment and a conventional valve device. FIG. 3 is a cross-sectional explanatory view showing the operation of the valve device when air is supplied to a first pressure chamber and a second pressure chamber. FIG. 4 is a cross-sectional explanatory view showing the operation of the valve device when air is discharged from the first pressure chamber and a second pressure chamber. FIG. 5 is a cross-sectional view showing an actuator according to a first modified example. FIG. 6 is a cross-sectional view showing an actuator according to a second modified example. FIG. 7 is a cross-sectional view showing an actuator according to a third modified example.

[0008] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention (hereinafter also referred to as the present embodiment) will be described with reference to the accompanying drawings. In this specification, the same elements are designated by the same reference numerals throughout.

[0009] [Configuration of Valve Device] First, a valve device 100 according to this embodiment will be described with reference to FIGS. 1 to 2B.

[0010] FIG. 1 is a cross-sectional view showing a valve device 100 according to the present embodiment. FIG. 2A is a graph showing an example of the relationship between the operating time and air pressure when the valve is opened for the valve device 100 according to the present embodiment and a conventional valve device. FIG. 2B is a graph showing an example of the relationship between the operating time and air pressure when the valve is closed for the valve device 100 according to the present embodiment and a conventional valve device. The conventional valve device is described in JP2017-44290A. The operating time when the valve is opened is the time from when a command to open the valve is received until the valve actually reaches the open state, and the operating time when the valve is closed is the time from when a command to close the valve is received until the valve actually reaches the closed state.

[0011] 1, a valve device 100 according to this embodiment is provided in a fluid control device (not shown) used in semiconductor manufacturing. The fluid control device is used as a supply means for process gas or purge gas in semiconductor manufacturing equipment (CVD equipment, sputtering equipment, etching equipment, etc. (not shown)).

[0012] 1, the valve device 100 includes a valve body 1, a stem 2, a valve element 3, a support ring 4, a bellows 5, a bonnet 6, a connecting member 7, a first compression coil spring 8, an actuator 9, and a lock nut 10. In this embodiment, the valve device 100 is configured as a normally closed valve device.

[0013] The valve body 1 comprises a valve body main body 11, a fluid inlet flow path 12 and a fluid outlet flow path 13 formed in the valve body main body 11, a valve chamber 14 having a stepped portion 14 a formed in the valve body main body 11 so as to communicate an upper end portion as one end of the fluid inlet flow path 12 with an upper end portion as one end of the fluid outlet flow path 13, an annular (specifically, circular) valve seat 15 provided in the valve chamber 14 so as to be located on the periphery of the upper end portion of the fluid inlet flow path 12, a peripheral wall 16 surrounding the valve chamber 14, and a first female thread 17 located above the valve chamber 14 and formed on the inner surface of the upper end portion of the peripheral wall 16 so as to threadably engage with the bonnet 6.

[0014] The stem 2 is housed in the valve chamber 14. The stem 2 has a columnar (specifically, cylindrical) stem body 21 extending in the vertical direction, a first threaded rod 22 protruding from the upper end of the stem body 21 and threadably engaging with the connecting member 7, and a ring-shaped (specifically, circular) first flange 23 provided at the lower end, which serves as the tip of the stem body 21.

[0015] The valve element 3 opens and closes a fluid inlet flow path 12 as a flow path by being seated on and separated from a valve seat 15. The valve element 3 is provided at the lower end portion as the tip portion of the stem 2.

[0016] In this embodiment, the valve body is composed of a valve body 3 fixed to the lower end of the stem 2, but this is not limited to this and may be composed of, for example, a diaphragm located below the stem 2.

[0017] The support ring 4 is placed on the step portion 14a. The stem body 21 is inserted into the inner periphery of the support ring 4. A first O-ring O1 is provided between the support ring 4 and the peripheral wall 16.

[0018] The bellows 5 has its upper and lower ends welded to the support ring 4 and the first flange 23 , respectively, and is provided between the support ring 4 and the first flange 23 so as to surround the stem body 21 .

[0019] The bonnet 6 is a member for connecting the valve body 1 and the actuator 9. The bonnet 6 has a substantially cylindrical (specifically, cylindrical) bonnet body 61, a first male thread 62 formed on the outer peripheral surface of the lower end of the bonnet body 61 so as to threadably engage with the first female thread 17, a ring portion 63 provided on the inner peripheral side of the upper end of the bonnet body 61, and a second female thread 64 formed on the inner peripheral surface of the ring portion 63 so as to threadably engage with a second male thread 9114 (described later) of the actuator 9. Note that when the first female thread 17 and the first male thread 62 are threadably engaged with each other, the support ring 4 is sandwiched between the stepped portion 14a and the bonnet body 61.

[0020] The connecting member 7 is a member for connecting the stem 2 and a piston rod 94 (described later) of the actuator 9. The connecting member 7 is housed on the inner peripheral side of the bonnet 6 (specifically, the bonnet body 61). The connecting member 7 has a columnar (specifically, cylindrical) connecting member body 71, a first threaded hole 72 formed at the upper end of the connecting member body 71 and threadedly engaged with a second threaded rod 941 (described later), a second threaded hole 73 formed at the lower end of the connecting member body 71 and threadedly engaged with the first threaded rod 22, and a second flange 74 formed on the outer peripheral surface of the lower end of the connecting member body 71.

[0021] The first compression coil spring 8 is held between the second flange 74 and the ring portion 63 so as to surround the connecting member main body 71. As a result, the first compression coil spring 8 biases the connecting member 7 downward.

[0022] The actuator 9 is a driving unit that moves the stem 2 in the vertical direction (i.e., in the extending direction of the stem 2) to seat and separate the valve element 3 from the valve seat 15. Details of the actuator 9 will be described later.

[0023] The lock nut 10 is used to lock the bonnet 6. A third female thread 101 that threadably engages with the second male thread 9114 is formed on the inner peripheral surface of the lock nut 10.

[0024] [Configuration of Actuator] Next, the actuator 9, which is a feature of this embodiment, will be described in detail with reference to FIG.

[0025] 1 , the actuator 9 is a multi-stage cylinder actuator. The actuator 9 includes a cylinder 91, a partition plate 92 as a partition, a lower-stage piston 93 as a first piston, a piston rod 94, an upper-stage piston 95 as a second piston, a first pressure chamber 96, a second pressure chamber 97, a second compression coil spring 98 as a biasing portion, a first tube L1 constituting a first sub-fluid flow path, and a second tube L2 constituting a second sub-fluid flow path. The lower-stage piston 93, the piston rod 94, and the upper-stage piston 95 constitute a piston portion.

[0026] In this embodiment, the outer periphery of the cylinder 91 is formed to be hexagonal in plan view, but this is not limited thereto, and the cylinder 91 may be formed to be, for example, quadrangular or octagonal.

[0027] The cylinder 91 is configured to include only a lower cylinder 911 as a first-stage cylinder and an upper cylinder 912 as a second-stage cylinder, but is not limited to this and may be configured to include, for example, an additional cylinder in addition to the lower cylinder 911 and the upper cylinder 912. In this case, another piston is slidably housed in the additional cylinder.

[0028] The lower cylinder 911 has a cylindrical lower cylinder body 9111 whose inner and outer circumferences are circular and hexagonal, respectively; an annular (specifically, annular) bottom wall 9112 provided on the inner side of the lower end of the lower cylinder body 9111; a cylindrical (specifically, cylindrical) protrusion 9113 protruding downward from the inner peripheral edge of the annular bottom wall 9112; a second male thread 9114 formed on the outer peripheral surface of the protrusion 9113 so as to threadably engage with both the second female thread 64 and the third female thread 101; a first communicating hole 9115 formed in the lower cylinder body 9111 near the upper end of the lower cylinder body 9111; and a first supply / discharge port 9116 formed in the lower cylinder body 9111 (i.e., the peripheral wall of the lower cylinder 911) near the lower end of the lower cylinder body 9111.

[0029] A lower-stage piston 93 is housed on the inner circumferential side of the lower-stage cylinder body 9111. The lower-stage piston 93 is slidable relative to the inner circumferential surface of the lower-stage cylinder body 9111. A second O-ring O2 is provided between the lower-stage piston 93 and the lower-stage cylinder body 9111.

[0030] The piston rod 94 is inserted into the inner periphery of the annular bottom wall 9112. A third O-ring O3 is provided between the annular bottom wall 9112 and the piston rod 94.

[0031] The piston rod 94 is inserted into the inner periphery of the cylindrical protrusion 9113 .

[0032] The actuator 9 is supported by the bonnet 6 in a state in which the second male thread 9114 is threadedly engaged with the second female thread 64 and the third female thread 101 .

[0033] The first communication hole 9115 is a hole for connecting the space located between the lower piston 93 and the partition plate 92 with the outside, thereby allowing air in the space located between the lower piston 93 and the partition plate 92 to be discharged to the outside.

[0034] The first supply / discharge port 9116 is a port that communicates with the first pressure chamber 96. One end of the first tube L1 is connected to the first supply / discharge port 9116 via a fitting (specifically, a one-touch fitting). This allows air to be supplied to and discharged from the first pressure chamber 96 through the first supply / discharge port 9116. One end of the first supply / discharge port 9116 opens to a flat surface (specifically, one of six flat surfaces) located on the outer periphery of the lower cylinder body 9111. In this embodiment, the first supply / discharge port 9116 is configured as a threaded hole that screws into the fitting. One end of the first tube L1 is inserted into the fitting.

[0035] In addition, in this embodiment, the first supply / discharge port is formed in the lower cylinder body 9111 (i.e., the peripheral wall of the cylinder 91), but this is not limited to this and may be formed, for example, in the bottom wall 9112 of the lower cylinder 911 (i.e., the bottom wall of the cylinder 91).

[0036] The upper cylinder 912 has a cylindrical upper cylinder body 9121 whose inner and outer circumferences are circular and hexagonal, respectively; an annular (specifically, annular) top wall 9122 provided on the inner side of the upper end of the upper cylinder body 9121; an annular (specifically, annular) first accommodating groove 9123 formed on the underside of the top wall 9122; a second communicating hole 9124 formed in the upper cylinder body 9121 near the upper end of the upper cylinder body 9121; and a second supply / discharge port 9125 formed in the upper cylinder body 9121 (specifically, in the peripheral wall of the upper cylinder 912) near the lower end of the upper cylinder body 9121.

[0037] An upper-stage piston 95 that is slidable along the inner circumferential surface of the upper-stage cylinder body 9121 is housed on the inner circumferential side of the upper-stage cylinder body 9121. A fourth O-ring O4 is provided between the upper-stage piston 95 and the upper-stage cylinder body 9121.

[0038] A protruding pillar 953 (described later) of the upper-stage piston 95 is inserted into the inner circumferential side of the annular top wall 9122. A fifth O-ring O5 is provided between the top wall 9122 and the protruding pillar 953.

[0039] The second communication hole 9124 is a hole for communicating the space located between the upper piston 95 and the top wall 9122 (i.e., the space in which the second compression coil spring 98 is accommodated) with the outside, thereby allowing air in the space located between the upper piston 95 and the top wall 9122 to be discharged to the outside.

[0040] The second supply / discharge port 9125 is a port that communicates with the second pressure chamber 97. One end of the second tube L2 is connected to the second supply / discharge port 9125 via a fitting (specifically, a one-touch fitting). This allows air to be supplied to and discharged from the second pressure chamber 97 through the second supply / discharge port 9125. One end of the second supply / discharge port 9125 opens to a flat surface (specifically, one of six flat surfaces) located on the outer periphery of the upper cylinder body 9121. In this embodiment, the second supply / discharge port 9125 is configured as a threaded hole that screws into the fitting. One end of the second tube L2 is inserted into the fitting.

[0041] One end of the first supply / discharge port 9116 and one end of the second supply / discharge port 9125 open on the same plane. This allows the first tube L1 and the second tube L2 to be integrated into one location, thereby saving space in the valve device 100. Note that one end of the first supply / discharge port 9116 and one end of the second supply / discharge port 9125 may open on different planes.

[0042] The partition plate 92 is fixed inside the cylinder 91 so as to be located between the lower piston 93 and the upper piston 95. Specifically, the partition plate 92 has an annular (specifically, circular) thick plate 921 and a thin plate 922 provided on the outer periphery of the thick plate 921 as the outer edge of the annular shape.

[0043] With the thin plate 922 of the partition plate 92 sandwiched between the lower cylinder 911 (specifically, the upper end of the lower cylinder body 9111) and the upper cylinder 912 (specifically, the lower end of the upper cylinder body 9121), a sixth O-ring O6 is provided between the annular thick plate 921 and the upper cylinder body 9121. Furthermore, with the thin plate 922 sandwiched between the lower cylinder body 9111 and the upper cylinder body 9121, the lower cylinder 911, the partition plate 92, and the upper cylinder 912 are fixed by, for example, screwing.

[0044] The lower piston 93 has a lower piston body 931 that is approximately disk-shaped (specifically, approximately disc-shaped) and is slidably mounted on the inner surface of the lower cylinder body 9111, a regulating portion 932 that protrudes upward from the center of the lower piston body 931, and a columnar (specifically, approximately cylindrical) insertion protrusion 933 that protrudes upward from the center of the regulating portion 932.

[0045] When the lower piston 93 slides upward relative to the lower cylinder 911, the regulating portion 932 abuts against the thick plate 921 of the partition plate 92, thereby regulating the upward sliding of the lower piston 93 relative to the lower cylinder 911.

[0046] The insertion protrusion 933 passes through the partition plate 92 (specifically, the inner peripheral side of the annular thick plate 921), and its tip is inserted into a housing recess 955 (described later) of the upper-stage piston 95. This allows the lower-stage piston 93 and the upper-stage piston 95 to slide up and down integrally. A seventh O-ring O7 is provided between the insertion protrusion 933 and the annular thick plate 921.

[0047] The piston rod 94 is provided so as to protrude downward from one side of the lower-stage piston 93 (specifically, the lower-stage piston main body 931). The piston rod 94 is provided with a second threaded rod 941 that protrudes downward from the lower end, which serves as the tip of the piston rod 94. The second threaded rod 941 is threadedly engaged with the first threaded hole 72, thereby connecting the connecting member 7 and the lower-stage piston 93 via the piston rod 94.

[0048] The upper piston 95 has an upper piston body 951 that is approximately disk-shaped (specifically, approximately disc-shaped) and is slidably mounted on the inner surface of the upper cylinder body 9121, a spring retaining portion 952 that protrudes upward from the center of the upper piston body 951, a protruding pillar 953 that protrudes upward from the center of the spring retaining portion 952 so as to be inserted into the inner side of the annular top wall 9122, a second annular (specifically, circular) accommodating groove 954 formed on the upper surface of the upper cylinder body 9121 so as to surround the spring retaining portion 952, and an accommodating recess 955 formed in the center of the lower surface of the upper cylinder body 9121 so as to press-fit the tip of the insertion protrusion 933.

[0049] When the second compression coil spring 98 is held by the spring holding portion 952, the upper end and lower end are housed in the first housing groove 9123 and the second housing groove 954, respectively.

[0050] The first pressure chamber 96 is formed by the lower piston 93, the piston rod 94, the bottom wall of the cylinder 91 (specifically, the bottom wall 9112 of the lower cylinder 911), and the peripheral wall of the cylinder 91 (specifically, the lower cylinder main body 9111). The first pressure chamber 96 is in communication with the first tube L1 via a first supply / discharge port 9116.

[0051] The lower-stage piston 93 slides downward relative to the lower-stage cylinder body 9111, minimizing the volume of the first pressure chamber 96. In this state, the sliding surface of the lower-stage piston body 931 and the second O-ring O2 are positioned above the first supply / discharge port 9116 (specifically, the opening of the first supply / discharge port 9116 located on the inner periphery of the lower-stage cylinder body 9111). This makes it possible to prevent communication between the first pressure chamber 96 and the first supply / discharge port 9116 from being blocked by the sliding surface of the lower-stage piston body 931 or the second O-ring O2.

[0052] The second pressure chamber 97 is formed by the upper piston 95, the partition plate 92, and the peripheral wall of the cylinder 91 (specifically, the upper cylinder body 9121). The second pressure chamber 97 is in communication with the second tube L2 via the second supply / discharge port 9125.

[0053] The upper-stage piston 95 slides downward relative to the upper-stage cylinder body 9121, minimizing the volume of the second pressure chamber 97. In this state, the sliding surface of the upper-stage piston body 951 and the fourth O-ring O4 are positioned above the second supply / discharge port 9125 (specifically, the opening of the second supply / discharge port 9125 located on the inner periphery of the upper-stage cylinder body 9121). This makes it possible to prevent communication between the second pressure chamber 97 and the second supply / discharge port 9125 from being blocked by the sliding surface of the upper-stage piston body 951 or the fourth O-ring O4.

[0054] The second compression coil spring 98 biases the lower-stage piston 93 and the upper-stage piston 95 downward so that the volumes of the first pressure chamber 96 and the second pressure chamber 97 become smaller.

[0055] In the present embodiment, the actuator 9 is configured to include the second compression coil spring 98, but is not limited to this and may be configured, for example, without the second compression coil spring 98. In this case, the first compression coil spring 8 can urge the connecting member 7 and the piston portions connected by the connecting member 7 (specifically, the lower-stage piston 93, the piston rod 94, and the upper-stage piston 95) downward.

[0056] The first tube L1 communicates between the first pressure chamber 96 and a first solenoid valve B1 serving as a first valve. Specifically, the first tube L1 is provided such that one end is connected to the first supply / discharge port 9116 and the other end is connected to the first solenoid valve B1, respectively.

[0057] The second tube L2 communicates between the second pressure chamber 97 and a second solenoid valve B2 serving as a second valve. Specifically, the second tube L2 is provided such that one end is connected to the second supply / discharge port 9125 and the other end is connected to the second solenoid valve B2, respectively.

[0058] The first tube L1 and the second tube L2 are provided in parallel (i.e., individually). Furthermore, from the viewpoint of synchronizing the timing of supplying air from the first solenoid valve B1 and the second solenoid valve B2 to the first pressure chamber 96 and the second pressure chamber 97, respectively, it is preferable that the lengths of the first tube L1 and the second tube L2 are the same. The first tube L1 and the second tube L2 have the same inner diameter. Therefore, the fluid volume from the first solenoid valve B1 to the first pressure chamber 96 and the flow path volume from the second solenoid valve B2 to the second pressure chamber 97 are the same.

[0059] Both the first solenoid valve B1 and the second solenoid valve B2 are connected to an air compressor A serving as a fluid supply source via a branch tube C. The branch tube C is composed of a first branch flow path C1 having one end connected to the first solenoid valve B1, a second branch flow path C2 having one end connected to the second solenoid valve B2, and a common flow path C3 having one end connected to both the other end of the first branch flow path C1 and the other end of the second branch flow path C2 and the other end connected to the air compressor A.

[0060] In this embodiment, the first tube L1 (including the joint), the first solenoid valve B1, the first branch flow path C1 of the branch tube C, and the common flow path C3 constitute the first fluid flow path, and the second tube L2 (including the joint), the second solenoid valve B2, the second branch flow path C2 of the branch tube C, and the common flow path C3 constitute the second fluid flow path.

[0061] The first solenoid valve B1 and the second solenoid valve B2 are configured to the same specifications (i.e., the same shape and dimensions). Furthermore, the first branch flow path C1 and the second branch flow path C2 are configured to have the same length and the same diameter. This makes the length of the first fluid flow path from the air compressor A to the first pressure chamber 96 the same as the length of the second fluid flow path from the air compressor A to the second pressure chamber 97. Furthermore, the volume of the first fluid flow path from the air compressor A to the first pressure chamber 96 is also the same as the volume of the second fluid flow path from the air compressor A to the second pressure chamber 97.

[0062] In addition, in this embodiment, both the first solenoid valve B1 and the second solenoid valve B2 are connected to the air compressor A via a branch tube C, but this is not limited to this, and for example, they may be connected to the air compressor A via two tubes arranged in parallel.

[0063] As described above, the length of the first fluid flow path formed by the first tube L1 (including the joint), the first solenoid valve B1, the first branch flow path C1 of the branch tube C, and the common flow path C3 is the same as the length of the second fluid flow path formed by the second tube L2 (including the joint), the second solenoid valve B2, the second branch flow path C2 of the branch tube C, and the common flow path C3, so that it is possible to reduce (eliminate) the time difference in air supply from the air compressor A to the two pressure chambers (specifically, the first pressure chamber 96 and the second pressure chamber 97). As a result, it is possible to improve the responsiveness of the valve device 100 when opening the fluid inlet flow path 12 of the valve body 1 (i.e., when the valve device 100 is opened) or when closing the fluid inlet flow path 12 (i.e., when the valve device 100 is closed).

[0064] Specifically, as shown in Fig. 2A, the valve device 100 according to this embodiment has a significantly shorter valve opening time (i.e., response time) at each operating air pressure than the conventional valve device. On the other hand, as shown in Fig. 2B, the valve device 100 according to this embodiment has a significantly shorter valve closing time (i.e., response time) at each operating air pressure than the conventional valve device. Note that when the valve device 100 is fully open and fully closed, the volumes of the first pressure chamber 96 and the second pressure chamber 97 are the same.

[0065] The first sub-fluid flow path connecting the first pressure chamber 96 and the first solenoid valve B1 and the second sub-fluid flow path connecting the second pressure chamber 97 and the second solenoid valve B2 are each composed of a first tube L1 and a second tube L2 arranged in parallel, and therefore the speed at which air is supplied to each pressure chamber can be improved compared to when air is supplied to two pressure chambers (specifically, the first pressure chamber 96 and the second pressure chamber 97) through a single fluid flow path, thereby improving the responsiveness of the valve device 100 when opening the fluid inlet flow path 12 of the valve body 1 (i.e., when the valve device 100 is opened).

[0066] On the other hand, compared to when air is discharged from two pressure chambers (specifically, the first pressure chamber 96 and the second pressure chamber 97) through a single fluid flow path, the air discharged from the two pressure chambers (specifically, the first pressure chamber 96 and the second pressure chamber 97) does not collide in the first tube L1 or the second tube L2, and the responsiveness of the valve device 100 can be improved even when the fluid inlet flow path 12 of the valve body 1 is closed (i.e., when the valve device 100 is closed).

[0067] Furthermore, as described above, one end of the first tube L1 and the second tube L2 is connected via a fitting to the first supply / discharge port 9116 formed in the lower cylinder body 9111 (i.e., the peripheral wall of the cylinder 91) and the second supply / discharge port 9125 formed in the upper cylinder body 9121 (i.e., the peripheral wall of the cylinder 91), respectively. Therefore, there is no need to form a separate fluid flow path in the lower piston 93 or the upper piston 95 that communicates with the first pressure chamber 96 or the second pressure chamber 97, and the structure of the lower piston 93 and the upper piston 95 can be simplified.

[0068] [Operation of the Valve Device] Next, the operation of the valve device 100 will be described with reference to FIGS.

[0069] Fig. 3 is a cross-sectional explanatory view showing the operation of the valve device 100 when air is supplied to the first pressure chamber 96 and the second pressure chamber 97. Fig. 4 is a cross-sectional explanatory view showing the operation of the valve device 100 when air is exhausted from the first pressure chamber 96 and the second pressure chamber 97.

[0070] As shown by arrow R1 in FIG. 3 , air from air compressor A is supplied to the first pressure chamber 96 via the first solenoid valve B1, the first tube L1, and the first supply / discharge port 9116, and air from air compressor A is supplied to the second pressure chamber 97 via the second solenoid valve B2, the second tube L2, and the second supply / discharge port 9125. As a result, the piston portion (specifically, the lower-stage piston 93, the piston rod 94, and the upper-stage piston 95) moves upward (in the direction shown by arrow R2 in FIG. 3 ) together with the connecting member 7, the stem 2, and the valve disc 3 against the biasing forces of the first compression coil spring 8 and the second compression coil spring 98, increasing the volumes of the first pressure chamber 96 and the second pressure chamber 97. The valve disc 3 then lifts off the valve seat 15, opening the fluid inlet flow path 12 of the valve body 1. This allows a fluid, such as a process gas, from the fluid inlet flow path 12 to be supplied to the fluid outlet flow path 13 via the valve chamber 14.

[0071] On the other hand, when air from the air compressor A is not supplied to the first pressure chamber 96 and the second pressure chamber 97, the piston portion (specifically, the lower-stage piston 93, the piston rod 94, and the upper-stage piston 95) moves downward (in the direction indicated by arrow R3 in FIG. 4 ) together with the connecting member 7, the stem 2, and the valve body 3 under the biasing force of the first compression coil spring 8 and the second compression coil spring 98, so that the volumes of the first pressure chamber 96 and the second pressure chamber 97 decrease. At this time, as indicated by arrow R4 in FIG. 4 , the air in the first pressure chamber 96 and the second pressure chamber 97 is discharged to the first solenoid valve B1 via the first supply / discharge port 9116 and the first tube L1, and to the second solenoid valve B2 via the second supply / discharge port 9125 and the second tube L2. The valve body 3 then seats on the valve seat 15, closing the fluid inlet flow path 12 of the valve body 1. As a result, the fluid such as the process gas from the fluid inlet passage 12 is not supplied to the fluid outlet passage 13 via the valve chamber 14 .

[0072] [Operation and Effect] Next, the operation and effect of this embodiment will be described.

[0073] The actuator 9 according to this embodiment is an actuator 9 used in a valve device 100, and includes a cylinder 91, a lower-stage piston 93 (first piston) housed in the cylinder 91 so as to be slidable along the inner circumferential surface of the cylinder 91, a piston rod 94 provided so as to protrude to one side from the lower-stage piston 93 (first piston), an upper-stage piston 95 (second piston) provided on the other side of the lower-stage piston 93 (first piston) and housed in the cylinder 91 so as to be slidable along the inner circumferential surface of the cylinder 91, a partition plate 92 (partition portion) fixed within the cylinder 91 so as to be located between the lower-stage piston 93 (first piston) and the upper-stage piston 95 (second piston), and the lower-stage piston 93 (first piston). a first pressure chamber 96 formed by the piston rod 94, a bottom wall 9112 of the lower cylinder 911 (bottom wall of the cylinder 91) and the lower cylinder body 9111 (circumferential wall of the cylinder 91); a second pressure chamber 97 formed by the upper piston 95 (second piston), a partition plate 92 (partition portion) and the upper cylinder body 9121 (circumferential wall of the cylinder 91); a first fluid flow path connecting the first pressure chamber 96 and an air compressor A (fluid supply source); and a second fluid flow path connecting the second pressure chamber 97 and the air compressor A (fluid supply source), the length from the air compressor A (fluid supply source) to the second pressure chamber 97 being the same as the length of the first fluid flow path from the air compressor A (fluid supply source) to the first pressure chamber 96.

[0074] The valve device 100 according to this embodiment includes a valve body 1 having a fluid inlet flow path 12 (flow path) formed therein and a valve seat 15; a valve element 3 that opens and closes the fluid inlet flow path 12 (flow path) by being seated on and removed from the valve seat 15; a stem 2 having the valve element 3 at its tip; and the actuator 9 described above that moves the stem 2 along the extension direction of the stem 2 to seat and remove the valve element 3 from the valve seat 15.

[0075] According to these configurations, it is possible to suppress (eliminate) the time difference in the supply of air from the air compressor A to the two pressure chambers (specifically, the first pressure chamber 96 and the second pressure chamber 97), thereby improving the responsiveness of the valve device 100 when opening the fluid inlet passage 12 of the valve body 1 (i.e., when the valve device 100 is opened) or when closing the fluid inlet passage 12 (i.e., when the valve device 100 is closed).

[0076] In addition, in this embodiment, a first solenoid valve B1 (first valve) is provided between the first pressure chamber 96 and the air compressor A (fluid supply source), and the first fluid flow path has a first tube L1 (first sub-fluid flow path) that connects the first pressure chamber 96 and the first solenoid valve B1 (first valve), and a second solenoid valve B2 (second valve) is provided between the second pressure chamber 97 and the air compressor A (fluid supply source), and the second fluid flow path has a second tube L2 (second sub-fluid flow path) that connects the second pressure chamber 97 and the second solenoid valve B2 (second valve) and is provided separately from the first tube L1 (first sub-fluid flow path).

[0077] With this configuration, the speed at which air is supplied to each pressure chamber can be increased compared to when air is supplied to two pressure chambers (specifically, the first pressure chamber 96 and the second pressure chamber 97) through a single fluid flow path, thereby improving the responsiveness of the valve device 100 when the fluid inlet flow path 12 of the valve body 1 is opened (i.e., when the valve device 100 is opened).

[0078] On the other hand, compared to when air is discharged from two pressure chambers (specifically, the first pressure chamber 96 and the second pressure chamber 97) through a single fluid flow path, the air discharged from the two pressure chambers (specifically, the first pressure chamber 96 and the second pressure chamber 97) does not collide in the first tube L1 or the second tube L2, and the responsiveness of the valve device 100 can be improved even when the fluid inlet flow path 12 of the valve body 1 is closed (i.e., when the valve device 100 is closed).

[0079] In addition, in this embodiment, a first supply / discharge port 9116 communicating with the first pressure chamber 96 is formed in the lower cylinder body 9111 (circumferential wall of the cylinder 91), and a second supply / discharge port 9125 communicating with the second pressure chamber 97 is formed in the upper cylinder body 9121 (circumferential wall of the cylinder 91), and the first tube L1 (first sub-fluid flow path) is connected to the first supply / discharge port 9116, and the second tube L2 (second sub-fluid flow path) is connected to the second supply / discharge port 9125.

[0080] In addition, in this embodiment, the cylinder 91 has a lower cylinder 911 (first stage cylinder) that accommodates a lower piston 93 (first piston), and an upper cylinder 912 (second stage cylinder) that is provided separately from the lower cylinder 911 (first stage cylinder) and accommodates an upper piston 95 (second piston), and the partition plate 92 (partition portion) has a thin plate 922 (outer edge) that is sandwiched between the lower cylinder 911 (first stage cylinder) and the upper cylinder 912 (second stage cylinder), and the first supply and discharge port 9116 is formed in the lower cylinder main body 9111 (circumferential wall of the lower cylinder 911 (first stage cylinder)), and the second supply and discharge port 9125 is formed in the upper cylinder main body 9121 (circumferential wall of the upper cylinder 912 (second stage cylinder)).

[0081] With these configurations, there is no need to form a separate fluid flow path in the lower piston 93 or the upper piston 95 that communicates with the first pressure chamber 96 or the second pressure chamber 97, and the structure of the lower piston 93 and the upper piston 95 can be simplified.

[0082] [Modifications] Next, the actuator 9 according to each modification will be described with reference to Fig. 5 to Fig. 7. Note that a description of points that are the same as the above-described embodiment will be omitted, and differences from the above-described embodiment will be mainly described.

[0083] Fig. 5 is a cross-sectional view showing an actuator 9 according to a first modified example, Fig. 6 is a cross-sectional view showing an actuator 9 according to a second modified example, and Fig. 7 is a cross-sectional view showing an actuator 9 according to a third modified example.

[0084] In the above-described embodiment, the first fluid flow path and the second fluid flow path are respectively composed of a first tube L1 connected to the first supply / discharge port 9116 and a second tube L2 connected to the second supply / discharge port 9125, but this is not limited to this. For example, as shown in FIG. 5, the first fluid flow path and the second fluid flow path may respectively be composed of a first tube L1 connected to the first supply / discharge port 9116, a second tube L2 connected to the inner peripheral edge of the annular top wall 9122, and an upper piston flow path 956 formed in the upper piston 95.

[0085] 5, the upper piston flow path 956 communicates between the second tube L2 and the second pressure chamber 97. Furthermore, the upper cylinder body 9121 does not have a second supply / discharge port.

[0086] Furthermore, in the above-described embodiment, the first fluid flow path and the second fluid flow path are respectively composed of a first tube L1 connected to the first supply / discharge port 9116 and a second tube L2 connected to the second supply / discharge port 9125, but this is not limited to this. For example, as shown in FIG. 6, each may be composed of a first tube L1 connected to the inner peripheral edge of the annular top wall 9122, piston flow paths L3 formed in both the upper piston 95 and the lower piston 93, and a second tube L2 connected to the second supply / discharge port 9125.

[0087] 6, the piston flow path L3 communicates between the first tube L1 and the first pressure chamber 96. Furthermore, the lower cylinder body 9111 does not have a first supply / discharge port.

[0088] Furthermore, in the above-described embodiment, the first fluid flow path and the second fluid flow path are respectively composed of a first tube L1 connected to the first supply / discharge port 9116 and a second tube L2 connected to the second supply / discharge port 9125, but this is not limited to this. For example, as shown in FIG. 7, the first fluid flow path and the second fluid flow path may respectively be composed of a first tube L1 connected to the first communication hole 9122a in the top wall 9122 and a first piston flow path L4 formed in the upper piston 95 and the lower piston 93, and a second tube L2 connected to the second communication hole 9122b in the top wall 9122 and a second piston flow path L5 formed in the upper piston 95 and the lower piston 93.

[0089] 7, the first piston flow path L4 connects the first tube L1 to the first pressure chamber 96, and the second piston flow path L5 connects the second tube L2 to the second pressure chamber 97. The first piston flow path L4 is longer than the second piston flow path L5. It is preferable to make the length of the first tube L1 shorter than the second tube L2 by this difference in length. Furthermore, the lower cylinder body 9111 and the upper cylinder body 9121 do not have a first supply / discharge port or a second supply / discharge port, respectively.

[0090] According to the actuator 9 of the third modification, the first tube L1 and the second tube L2 are respectively connected to the first communication hole 9122a and the second communication hole 9122b that penetrate the top wall 9122 of the cylinder 91, and therefore the first tube L1 and the second tube L2 can be disposed above the cylinder 91. As a result, compared to a structure in which the tubes are connected to the peripheral wall of the cylinder 91, the radial size of the actuator 9 (or the valve device 100) can be reduced.

[0091] The present embodiment has been described above, but the above-described embodiment merely illustrates some of the application examples of the present invention, and is not intended to limit the technical scope of the present invention to the specific configurations of the above-described embodiment.

[0092] This application claims priority based on Japanese Patent Application No. 2023-203068, filed with the Japan Patent Office on November 30, 2023, the entire contents of which are incorporated herein by reference.

Claims

1. An actuator for use in a valve device, comprising: a cylinder; a first piston housed within the cylinder so as to be slidable against an inner circumferential surface of the cylinder; a piston rod provided so as to protrude to one side from the first piston; a second piston provided on the other side of the first piston and housed within the cylinder so as to be slidable against the inner circumferential surface of the cylinder; a partition portion fixed within the cylinder so as to be located between the first and second pistons; a first pressure chamber formed by the first piston, the piston rod, a bottom wall of the cylinder, and a peripheral wall of the cylinder; a second pressure chamber formed by the second piston, the partition portion, and the peripheral wall of the cylinder; a first fluid flow path communicating the first pressure chamber with a fluid supply source; and a second fluid flow path communicating the second pressure chamber with the fluid supply source, wherein the length from the fluid supply source to the second pressure chamber is the same as the length of the first fluid flow path from the fluid supply source to the first pressure chamber.

2. An actuator as described in claim 1, wherein a first valve is provided between the first pressure chamber and the fluid supply source, the first fluid flow path having a first sub-fluid flow path connecting the first pressure chamber and the first valve, and a second valve is provided between the second pressure chamber and the fluid supply source, and the second fluid flow path has a second sub-fluid flow path connecting the second pressure chamber and the second valve and provided separately from the first sub-fluid flow path.

3. An actuator as described in claim 2, wherein a first supply / exhaust port communicating with the first pressure chamber is formed in a peripheral wall of the cylinder, a second supply / exhaust port communicating with the second pressure chamber is formed in a peripheral wall of the cylinder, the first sub-fluid flow path is connected to the first supply / exhaust port, and the second sub-fluid flow path is connected to the second supply / exhaust port.

4. The actuator described in claim 3, wherein the cylinder has a first stage cylinder in which the first piston is accommodated, and a second stage cylinder provided separately from the first stage cylinder in which the second piston is accommodated, the partition portion has an outer edge sandwiched between the first stage cylinder and the second stage cylinder, the first supply and exhaust port is formed in a peripheral wall of the first stage cylinder, and the second supply and exhaust port is formed in a peripheral wall of the second stage cylinder.

5. An actuator as described in claim 2, wherein a first supply / discharge port communicating with the first pressure chamber and connected to the first sub-fluid flow path, or a second supply / discharge port communicating with the second pressure chamber and connected to the second sub-fluid flow path, is formed on the peripheral wall of the cylinder.

6. A valve device comprising: a valve body having a flow path formed therein and a valve seat; a valve disc that opens and closes the flow path by being seated on and removed from the valve seat; a stem having the valve disc provided at its tip; and an actuator as set forth in any one of claims 1 to 5, which moves the stem along the extension direction of the stem to seat and remove the valve disc from the valve seat.