Valve actuator and shaft mount

Abstract

The invention provides a valve actuator and a shaft mounting member which can improve waterproof performance around a shaft through a simple structure without complicated waterproof treatment. An actuator (1) for a valve is provided with: an actuator body (10) having an external attachment mounting surface (14aa) on the upper part thereof, the external attachment mounting surface (14aa) being free to attach an external attachment (M); a shaft (20), one end of the lower part of which is connected to the valve rod of the valve, and the upper end of the other end of which protrudes from the inner side to the outer side of the actuator body (10) through a through hole (14b) formed in the external mounting member mounting surface (14aa); and a shaft mounting member (30) mounted on the shaft (20) so as to be rotatable together with the shaft (20) above the external mounting member mounting surface (14aa). In the outer mounting member placement surface (14aa), an annular protrusion (14c) protruding beyond the periphery is integrally formed with the outer mounting member placement surface (14aa) in a region inside the shaft mounting member (30) in plan view, so that an opening portion (14bb) of the through hole (14b) is located at a position higher than the periphery of the opening portion (14bb).

Description

Technical Field

[0001] The present invention relates to a valve actuator and a shaft mounting member, and more particularly to a valve actuator having a shaft and a shaft mounting member, wherein one end of the shaft below is connected to the valve stem of the valve, and the upper end of the other end where an external mounting member can be freely mounted passes through a through hole of the actuator body and protrudes from the inside of the actuator body to the outside. Background Art

[0002] Conventionally, in a valve actuator, as the shaft serving as a drive shaft, one end below is connected to the valve stem of the valve, and the upper end of the other end is provided to protrude from the actuator body for the installation of shaft mounting members such as indicators, external mounting members such as limit switches or speed controllers.

[0003] In such a valve actuator, since the shaft passes through a through hole formed in the actuator body and penetrates from the inside to the outside, when it is installed outdoors, there is a risk that water such as rainwater easily penetrates through the through hole into the actuator body, and internal corrosion may occur due to the penetrated water.

[0004] For example, in Patent Document 1, there is described a device in which the inner surface of the through hole through which a movable member (corresponding to a shaft) passes is a hydrophobic surface to prevent water from penetrating through the through hole into the shell.

[0005] Furthermore, in this Patent Document 1, there is also described a device in which a conical scraping plate protruding outward from the shell is provided in the area of the through hole of the shell (refer to FIG. 2 of Patent Document 1), the surface of the scraping plate is a hydrophobic surface, and together with the hydrophobic surface of the inner surface of the through hole, it prevents water from penetrating through the through hole into the shell, and the scraping plate scrapes off contaminants transported by the movable member in the direction of the scraping plate.

[0006] In addition, conventionally, in a valve or a valve actuator, when a shaft mounting member such as an indicator is installed at the upper end of the shaft serving as the valve stem or a drive shaft connected to the valve stem, or when an operation handle of the valve is connected, the upper end is provided to protrude from the valve body or the actuator body.

[0007] For example, Patent Document 2 describes a valve system in which an indicator is installed at the upper end of a valve stem protruding from a valve body.

[0008] Patent Document 1: U.S. Patent No. 10,624,224 Specification.

[0009] Patent Document 2: Japanese Patent Application Laid-Open No. 2022-500600.

[0010] However, in the device described in Patent Document 1, in order to prevent water from invading from the gap between the movable member and the shell, it is necessary to apply a complicated hydrophobic coating.

[0011] Although the size of the scraping plate is not described at all in Patent Document 1, considering another function of the scraping plate in addition to the waterproof function brought by the hydrophobic coating applied to the surface of the scraping plate, that is, scraping off the contaminants transported in the direction of the scraping plate by the movable member, it is speculated that the scraping plate is a conical shape with a certain degree of height and width.

[0012] However, the valve actuator has a shaft mounting member installed at the upper end of the shaft, and an external mounting member is installed on the upper surface of the actuator body that protrudes through the through hole with respect to the upper end.

[0013] Such a valve actuator sets various dimensions in a manner that conforms to actuator interface specifications such as NAMUR specifications.

[0014] Therefore, in terms of size, it is difficult to apply the scraping plate with a certain degree of height and width required to achieve the function of scraping off contaminants described in Patent Document 1 to the upper surface of the actuator body of the valve actuator.

[0015] On the other hand, even if a waterproof wall conforming to the NAMUR specification is provided instead of the scraping plate, the structure may become complicated.

[0016] In addition, in the valve system described in Patent Document 2, since the valve stem passes through the through hole formed in the valve body and penetrates from the inside of the valve body to the outside, when it is installed outdoors, water such as rainwater easily penetrates into the valve body along the valve stem through the through hole, and the internal part or the valve stem itself may be corroded due to the infiltrated water.

[0017] This problem also exists in the valve actuator whose shaft is connected to the valve stem of the valve.

[0018] That is, in the valve actuator, the shaft penetrates from the inside of the actuator body to the outside, so water such as rainwater easily penetrates into the actuator body along the shaft through the through hole, and the internal part or the shaft itself may be corroded due to the infiltrated water.

[0019] In particular, when the upper end of the shaft on which the shaft mounting member such as an indicator is installed is set to be a prismatic shape that can be freely disassembled and rotated for operating the manual handle, for example, the vertical planar side surface of the prismatic part and the upper surface of the shaft mounting member installed on the prismatic part form an inward corner that intersects at a substantially right angle.

[0020] At such an inward corner formed by intersecting at a substantially right angle, water easily contacts both the side surface of the prismatic part and the upper surface of the shaft mounting member, so water easily stays around the shaft, and there is a possibility that the stagnant water penetrates through the shaft and into the valve body or the actuator body, thereby corroding the inside of the valve body or the actuator body or the shaft itself. Summary of the Invention

[0021] The present invention is developed to solve the problems in the past, and its purpose is to provide a valve actuator and a shaft mounting member that can improve the waterproof performance around the shaft with a simple structure.

[0022] In order to achieve the above object, the invention of Technical Solution 1 is a valve actuator, comprising: an actuator body having an outer mounting member placement surface on the upper part where an outer mounting member can be freely mounted; a shaft, one end of which at the lower part is connected to the valve stem of the valve, and the upper end of the other end passes through a through hole formed in the outer mounting member placement surface and protrudes from the inside of the actuator body to the outside; a shaft mounting member that is rotatably mounted above the outer mounting member placement surface together with the shaft; the valve actuator is characterized in that on the outer mounting member placement surface, in the region that becomes the inside of the shaft mounting member when viewed from above, there is an annular convex portion integrally formed with the outer mounting member placement surface and protruding more than the surrounding area, so that the opening portion of the through hole is at a position higher than its periphery.

[0023] The invention of Technical Solution 2 is a valve actuator, and the outer mounting member placement surface is a surface including a flange portion that is enlarged in a flange shape on the upper part of the actuator body.

[0024] The invention of Technical Solution 3 is a valve actuator, and the outer mounting member placement surface is a drainage surface that is lower than the annular convex portion in the region outside the annular convex portion.

[0025] The invention of Technical Solution 4 is a valve actuator having one or more shaft auxiliary parts for rotatably holding the shaft at a predetermined position relative to the actuator body, and the shaft auxiliary parts are provided above the annular convex portion and below the shaft mounting member.

[0026] The invention of Technical Solution 5 is a valve actuator, and the shaft auxiliary parts are arranged in the region that becomes the inside of the shaft mounting member when viewed from above.

[0027] The invention of Technical Solution 6 is a valve actuator, the shaft mounting member has a shaft insertion through hole, the shaft insertion through hole has a shape corresponding to the cross-section of the shaft orthogonal to the shaft body, the upper end of the shaft passes through the shaft insertion through hole, the shaft mounting member is mounted on the shaft, the indicator has a top wall formed with the shaft insertion through hole, and a peripheral side wall hanging down along the outer peripheral edge surface of the top wall. The relative position relationship in the height direction between the lower end edge of the peripheral side wall and the opening portion of the through hole is set such that the lower end edge of the peripheral side wall is located below the opening portion of the through hole.

[0028] The invention of Technical Solution 7 is a valve actuator. The shaft has a prismatic portion and a cylindrical portion below the prismatic portion, with the diameter of the cross-section of the cylindrical portion being larger than the distance between the opposite side surfaces of the prismatic portion. The shaft insertion hole of the indicator is in a shape corresponding to the outer shape of the prismatic portion. The indicator is such that the prismatic portion is inserted through the shaft insertion hole and the lower surface of the top wall is seated on the boundary step portion between the prismatic portion and the cylindrical portion, thereby being mounted on the shaft.

[0029] The invention of Technical Solution 8 is a valve actuator. The lower end edge of the circumferential side wall of the indicator is set to be lower than the opening portion of the through hole and at a height away from the external mounting surface.

[0030] To achieve the above object, the invention of Technical Solution 9 is a shaft mounting member that is mounted on the columnar portion of the shaft protruding from the upper part of the valve body or the valve actuator body. The columnar portion has at least one planar side surface on the circumferential side surface and a corner portion formed by the side surfaces intersecting the planar side surface. The upper surface of the shaft mounting member extends in the radially outer direction of the shaft, and a water retention prevention portion is provided in the region of the upper surface close to the planar side surface of the columnar portion. The water retention prevention portion is configured with an upper end that suppresses the plane into a smaller upper end surface or an inclined surface, and a water guiding inclined surface is formed that slopes downward from the upper end surface or the upper end in the radially outer direction at a larger inclination angle than the region of the upper surface connected to the outer peripheral edge side.

[0031] The invention of Technical Solution 10 is a shaft mounting member. An enlarged planar portion is provided in the region of the upper surface close to the corner portion of the columnar portion of the shaft. The enlarged planar portion has an upper end surface formed by a plane whose width is enlarged in the radially outer direction compared to the upper end surface of the water retention prevention portion.

[0032] The invention of Technical Solution 11 is a shaft mounting member. When the annular fixing member is abutted against the enlarged planar portion and fixed to the shaft, the width in the radially outer direction of the upper end surface of the water retention prevention portion is set to be smaller than the maximum width in the radially outer direction of the gap between the inner circumferential surface of the annular fixing member and the planar side surface of the columnar portion of the shaft.

[0033] The invention of Technical Solution 12 is a valve actuator. The shaft mounting member according to any one of Technical Solutions 9 to 11 is mounted on the columnar portion of the shaft that is connected to the valve stem of the valve and protrudes from the upper part of the actuator body. The columnar portion has at least one planar side surface on the circumferential side surface and a corner portion formed by the side surfaces intersecting the planar side surface.

[0034] Advantages of the Invention

[0035] According to the invention of Technical Solution 1, in the externally mounted component placement surface, in the region that is the inner side of the shaft-mounted component when viewed from above, there is an annular convex portion integrally formed with the externally mounted component placement surface and protruding more than the surroundings, such that the opening portion of the through-hole is at a position higher than its periphery.

[0036] Thus, according to the invention of Technical Solution 1, by means of the shaft-mounted component mounted on the shaft, it is possible to prevent rainwater, etc. from directly falling onto the opening portion of the through-hole from above, preventing the intrusion of water. Also, regarding the water remaining on the externally mounted component placement surface, that is, the water remaining on the upper surface of the actuator body, it is difficult for the water to reach the opening portion of the through-hole that is at a position higher than the surroundings by means of the annular convex portion, so the intrusion into the through-hole is prevented.

[0037] Therefore, according to the invention of Technical Solution 1, it is possible to improve the waterproof function around the shaft by means of the annular convex portion with a simple structure without affecting the installation space of the externally mounted component on the upper part of the actuator body. As a result, it is possible to improve the waterproof performance around the shaft with a simple structure.

[0038] According to the invention of Technical Solution 2, the externally mounted component placement surface is a surface including a flange portion that expands flange-like on the upper part of the actuator body. Thus, it is easy to adjust the area of the upper surface of the actuator body for mounting the externally mounted component to a size that conforms to the specifications. Also, regarding the water remaining on the upper surface that is expanded by means of the flange portion, it is possible to effectively prevent its intrusion into the through-hole by means of the annular convex portion.

[0039] According to the invention of Technical Solution 3, the externally mounted component placement surface becomes a drainage surface that is lower than the annular convex portion in the region outside the annular convex portion. Thus, there are no components such as walls that obstruct drainage around the annular convex portion, and the drainage property is improved. Therefore, it is not easy to have water remaining around the annular convex portion. As a result, it is possible to improve the waterproof performance around the shaft.

[0040] According to the invention of Technical Solution 4, there is one or more shaft auxiliary parts for rotatably holding the shaft relative to the actuator body at a predetermined position. The shaft auxiliary parts are provided above the annular convex portion and below the shaft-mounted component. Thus, by means of the annular convex portion, the intrusion of the water remaining on the externally mounted component placement surface, that is, the water remaining on the upper surface of the actuator body, is prevented. Therefore, it is possible to prevent the attachment of water to the shaft auxiliary parts that are located above the annular convex portion, and it is possible to prevent water from penetrating into the actuator body along the shaft auxiliary parts through the shaft and the through-hole.

[0041] According to the invention of Technical Solution 5, the shaft auxiliary parts are arranged in the region that is the inner side of the shaft-mounted component when viewed from above. Thus, the shaft-mounted component mounted on the shaft functions as an umbrella to prevent rain, etc. from falling onto the shaft auxiliary parts. Therefore, it is possible to prevent water from penetrating into the actuator body along the shaft auxiliary parts through the shaft and the through-hole.

[0042] According to the invention of Technical Solution 6, the shaft mounting member has a shaft insertion through-hole, and the shaft insertion through-hole has a shape corresponding to the cross-section of the shaft orthogonal to the shaft body. The upper end portion of the shaft passes through the shaft insertion through-hole and the shaft mounting member is mounted on the shaft. The indicator has a top wall formed with a shaft insertion through-hole and a peripheral side wall hanging down along the outer peripheral edge surface of the top wall. The relative position relationship in the height direction between the lower end edge of the peripheral side wall and the opening portion of the through-hole is set such that the lower end edge of the peripheral side wall is located at a position lower than the opening portion of the through-hole.

[0043] Thus, according to the invention of Technical Solution 6, the gap between the indicator and the upper surface of the actuator body has a complex and interleaved shape, and it is more difficult for the water remaining on the upper surface of the actuator body to invade the through-hole.

[0044] Therefore, according to the invention of Technical Solution 6, the waterproof function around the shaft can be further improved.

[0045] According to the invention of Technical Solution 7, the shaft has a prism portion and a cylindrical portion below the prism portion, and the diameter of the cross-section of the cylindrical portion is larger than the distance between the opposite side surfaces of the prism portion. The shaft insertion through-hole of the indicator has a shape corresponding to the outer shape of the prism portion. The indicator is such that the prism portion is inserted through the shaft insertion through-hole and the lower surface of the top wall is seated on the boundary step portion between the prism portion and the cylindrical portion and thus is mounted on the shaft.

[0046] Thus, according to the invention of Technical Solution 7, when the indicator is mounted on the shaft, the indicator is positioned in the mounting height direction by means of the boundary step portion.

[0047] Therefore, according to the invention of Technical Solution 7, the indicator can be positioned with high precision in the height direction relative to the upper end portion of the shaft, and can be simply mounted.

[0048] According to the invention of Technical Solution 8, the lower end edge of the peripheral side wall of the indicator is set to a height lower than the opening portion of the through-hole and away from the upper surface of the actuator body. Thus, even in the case where water accidentally invades the indicator, the water inside the indicator flows out from the gap between the lower end edge of the indicator and the upper surface of the actuator body, and the waterproof function around the shaft can be further improved.

[0049] According to the invention of Technical Solution 9, a water retention prevention portion is provided in a region of the upper surface close to the planar side surface of the columnar portion of the shaft. The water retention prevention portion is provided with an upper end surface that suppresses the plane to be smaller or an inclined surface, and is formed with a water guiding inclined surface that inclines downward at a larger inclination angle than the region of the upper surface connected to the outer peripheral edge side from the upper end surface or the upper end toward the radially outer direction.

[0050] Thus, in the region of the upper surface close to the planar side surface of the shaft, the upper end surface or the upper end of the inclined surface of the water retention prevention portion that suppresses the plane to be smaller is arranged. By means of the upper end surface or the upper end of the inclined surface that suppresses the plane to be smaller, the water contact area at the inward corner formed by the intersection of the planar side surface around the columnar portion of the shaft and the upper surface of the shaft mounting member is suppressed to be smaller.

[0051] Moreover, the water that is difficult to stay around the columnar portion of the shaft flows along the downward inclined surface of the water retention prevention portion toward the outer peripheral edge.

[0052] Therefore, it is possible to prevent water from staying around the shaft. As a result, the waterproof performance around the shaft can be improved.

[0053] In addition, the water guiding inclined surface with a large inclination angle is not provided in all regions in the radial outer direction of the upper surface of the shaft mounting member but is provided in a part, so that while exerting the water retention prevention effect around the shaft, the increase in the height dimension can be suppressed to be smaller.

[0054] According to the invention of Technical Solution 10, an enlarged planar portion is provided. The enlarged planar portion has an upper end surface formed by a plane whose width is enlarged in the radial outer direction compared with the upper end surface of the water retention prevention portion in the region of the upper surface close to the corner of the columnar portion of the shaft.

[0055] Thus, in the region close to the outer corners where water is difficult to stay around the columnar portion of the shaft, a surface for various components to abut is ensured. Therefore, while preventing water from staying around the shaft, various components can be stably abutted and arranged on the upper surface of the shaft mounting member.

[0056] According to the invention of Technical Solution 11, when the shaft mounting member fixes the annular fixing member by abutting it against the enlarged planar portion to the shaft, the width of the upper end surface of the water retention prevention portion in the radial outer direction is set to be smaller than the maximum width in the radial outer direction of the gap between the inner peripheral surface of the annular fixing member and the planar side surface of the columnar portion of the shaft.

[0057] Thus, even if water intrudes between the planar side surface of the columnar portion of the shaft and the inner peripheral surface of the annular fixing member, the water passes through the region of the upper surface that is lower than the upper end surface and is provided between the upper end surface of the water retention prevention portion and the annular fixing member and flows from the upper end surface of the water retention prevention portion to the outer peripheral edge.

[0058] Therefore, the shaft mounting member can be stably fixed to the columnar portion of the shaft by means of the annular fixing member, and the water that intrudes between the planar side surface of the columnar portion and the inner peripheral surface of the annular fixing member can be made to flow to the outer peripheral edge.

[0059] According to the invention of Technical Solution 12, a shaft mounting member as described in any one of Technical Solutions 9 to 11 is mounted on a columnar portion of a shaft that is connected to a valve stem of a valve and protrudes from the upper part of an actuator body. The columnar portion has at least one planar side surface on its circumferential side surface and a corner portion formed by side surfaces that intersect the planar side surface.

[0060] Thus, in a region of the upper surface close to the planar side surface of the shaft, the upper end surface of a water retention prevention portion that suppresses the plane to be smaller, or the upper end of an inclined surface, is arranged. By means of the upper end surface that suppresses the plane to be smaller, or the upper end of the inclined surface, the contact area of water at the inward corner formed by the intersection of the planar side surface around the columnar portion of the shaft and the upper surface of the shaft mounting member is suppressed to be smaller.

[0061] Moreover, water that is difficult to retain around the columnar portion of the shaft flows along the downwardly inclined inclined surface of the water retention prevention portion to the outer peripheral edge.

[0062] Therefore, it is possible to prevent water from retaining around the shaft. As a result, the waterproof performance around the shaft can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 is an exploded perspective view showing only the decomposition of the indicator of the valve actuator of Embodiment 1.

[0064] Figure 2A is Figure 1 a partial cross-sectional view of the valve actuator shown.

[0065] Figure 2B is Figure 2A an enlarged view of the periphery of the annular convex portion shown.

[0066] Figure 3 is a diagram for explaining a rotation conversion mechanism that converts the reciprocating motion of a piston into the rotational motion of a shaft.

[0067] Figure 4A is a diagram for explaining the installation process of the indicator.

[0068] Figure 4B is a diagram for explaining the installation process of the indicator.

[0069] Figure 5A is a diagram showing a modified example of the indicator.

[0070] Figure 5B is a diagram showing a modified example of the indicator.

[0071] Figure 6 is an exploded perspective view showing only the decomposition of the indicator of the valve actuator of Embodiment 2 of the present invention.

[0072] Figure 7It is a perspective view around the shaft of the valve actuator.

[0073] Figure 8 It is a top view around the shaft of the valve actuator.

[0074] Figure 9A It is Figure 8 A cross-sectional view taken along line IV-IV of the valve actuator shown.

[0075] Figure 9B It is Figure 9A An enlarged view around the upper end portion of the shaft shown.

[0076] Figure 10A It is Figure 8 A cross-sectional view taken along line V(a)-V(a) around the upper end portion of the shaft of the valve actuator shown.

[0077] Figure 10B It is Figure 8 A cross-sectional view taken along line V(b)-V(b) around the upper end portion of the shaft of the valve actuator shown.

[0078] Figure 11 It is a diagram for explaining a rotation conversion mechanism that converts the reciprocating motion of a piston into the rotational motion of a shaft.

[0079] Figure 12 It is a perspective view of the indicator.

[0080] Figure 13 It is a diagram for explaining the dimension of the width of the upper end surface of the water retention prevention portion.

[0081] Figure 14 It is a diagram showing a first modification example of the indicator.

[0082] Figure 15 It is a diagram showing a second modification example of the indicator.

[0083] Figure 16 It is a diagram showing a third modification example of the indicator.

[0084] Figure 17 It is a diagram for explaining an example of mounting the indicator on the valve stem of the valve. Detailed Description of the Invention

[0085] Based on Figure 1 ~FIG. 4, Embodiment 1 of the valve actuator 1 of the present invention will be described in detail.

[0086] In addition, the present invention is not limited by the embodiments shown below. Furthermore, it should be noted that the drawings are schematic, and the dimensional relationships between elements, the ratios of the elements, etc. are sometimes different from the actual ones. Moreover, there are sometimes parts with different dimensional relationships and ratios between the drawings.

[0087] Figure 1 This is an exploded perspective view showing only the decomposition of the indicator 30 of the valve actuator 1 of the embodiment. Figure 2A This is Figure 1 A partial cross-sectional view of the valve actuator 1 shown. Figure 2B This is Figure 2A An enlarged view of the periphery of the annular convex portion 14c shown. Figure 3 This is a diagram for explaining the power conversion mechanism that converts the reciprocating motion of the piston 41 into the rotational motion of the shaft 20. Figure 4A This is a diagram for explaining the installation process of the indicator 30. Figure 4B This is a diagram for explaining the installation process of the indicator 30.

[0088] The valve actuator 1 of Embodiment 1 of the present invention is a gas-driven actuator, and includes: an upper surface cover 14 of the actuator main body 10, which has an external mounting member placement surface 14aa on which a predetermined external mounting member can be freely mounted at the upper part; a shaft 20, one end of the lower part of which is connected to the valve stem of the valve, and the upper end portion 21 of the other end passes through a through hole 14b formed in the external mounting member placement surface 14aa and protrudes from the inside of the actuator main body 10, which is the inside of the upper surface cover 14, to the outside; an indicator 30, which is a shaft mounting member rotatably mounted on the shaft 20 together with the shaft 20.

[0089] In addition, the shaft mounting member is not necessarily limited to the indicator, and any part that can be rotatably mounted on the shaft together with the shaft can be used.

[0090] <Regarding the actuator main body 10>

[0091] The actuator main body 10 has: a pressure cylinder 11, which forms a space for sucking and discharging gas through two gas ports AP1 and AP2 and for reciprocating the piston 41 inside; a housing 12, which is connected to the pressure cylinder 11 and internally provided with a rotation conversion mechanism that converts the reciprocating motion of the piston 41 into a rotational motion and transmits it to the shaft 20 as an output shaft; and a housing cap 15, which seals one end opening of the housing 12.

[0092] <Regarding the housing 12 of the actuator main body 10>

[0093] The housing 12 includes a housing main body 13 internally provided with a rotation conversion mechanism and an upper surface cover 14 that closes the upper surface opening of the housing main body 13.

[0094] The housing main body 13 and the upper surface cover 14 are formed by casting. Thus, since the housing 12 is separately provided with the housing main body 13 and the upper surface cover 14, it is easy to form the annular convex portion 14c and the flange portion 14e described later with respect to the upper surface cover 14.

[0095] In addition, the housing 12 is not necessarily configured to separately provide the housing main body 13 and the upper surface cover 14. The upper surface cover 14 and the housing main body 13 may be integrally provided to form the housing 12, and a portion of the upper surface of the integrally provided housing 12 constitutes the external mounting member placement surface 14aa.

[0096] The rotation conversion mechanism provided in the housing main body 13 adopts a so-called anti-rotation yoke type mechanism. As shown in Figure 3 the rotation conversion mechanism has: an anti-rotation yoke 50 that engages with a pin P protruding radially outward from a piston rod 42 having a piston 41 provided at one end; and a shaft 20 that is connected to the anti-rotation yoke 50 by a key (not shown) and rotates and drives as an output shaft.

[0097] That is, the rotation conversion mechanism converts the reciprocating motion of the piston 41 into the rotational motion of the shaft 20 via the anti-rotation yoke 50.

[0098] One end below the shaft 20 is connected to the valve stem of the valve, and the upper end portion 21 of the other end passes through a through hole 14b formed in the external mounting member placement surface that is the upper surface of the housing 12 and protrudes from the inside to the outside of the housing 12.

[0099] Moreover, as shown in Figure 2B and Figure 3 the upper end portion 21 of the shaft 20 has a prism portion 21a and a cylindrical portion 21b. The cylindrical portion 21b is below the prism portion 21a, and the diameter of the cross section is larger than the distance between the opposing side surfaces of the prism portion 21a.

[0100] The boundary step portion 21c between the prism portion 21a and the cylindrical portion 21b is the portion for mounting the indicator 30.

[0101] On the cylindrical portion 21b of the shaft 20, one or more shaft auxiliary parts are provided for rotatably holding the shaft 20 in a predetermined position relative to the actuator main body 10.

[0102] In the first embodiment, as the shaft auxiliary parts, a thrust bearing 22, a washer 23, and a snap ring 24 are provided.

[0103] The thrust bearing 22 is mounted overlapping the convex upper surface 14d of a later-described annular convex portion 14c. The washer 23 is mounted overlapping the thrust bearing 22, and further, the shaft 20 is rotatably held in the housing 12 in a manner that it will not fall into the housing 12 by means of the snap ring 24 mounted overlapping the washer 23.

[0104] In addition, the shaft auxiliary parts are not limited to the thrust bearing 22, the washer 23, and the snap ring 24, and any parts can be used as long as they assist in rotatably holding the shaft 20 in a predetermined position relative to the actuator main body 10.

[0105] Further, a linear groove 21d for mounting various external mounting members M is provided on the upper surface of the prism portion 21a, i.e., the upper end surface of the shaft 20.

[0106] The linear groove 21d is set to a predetermined shape and size conforming to NAMUR specifications, for example, to ensure interchangeability in mounting various external mounting members other than the indicator 30.

[0107] An internal thread 21e for mounting an external mounting member is provided at the central position of the linear groove 21d, and a predetermined external mounting member can be mounted by using the internal thread 21e or the like.

[0108] The retaining ring 24, which is one of the shaft auxiliary parts, is sized such that its outer diameter is larger than the diameter of the through-hole 14b of the housing 12, and abuts against the edge surface of the through-hole 14b when the shaft 20 moves in a manner of falling into the housing 12.

[0109] In addition, in the present Embodiment 1, between the edge surface of the through-hole 14b, i.e., the surface around the opening portion 14bb of the through-hole 14b on the upper surface 14d of the convex portion of the annular convex portion 14c, and the retaining ring 24, the thrust bearing 22 and the washer 23, which are shaft auxiliary parts, are overlapped and arranged. Therefore, when the shaft 20 moves in a manner of falling into the housing 12, the retaining ring 24 abuts against the washer 23, but further falling is basically prevented by the upper surface 14d of the convex portion of the annular convex portion 14c.

[0110] <Regarding the upper surface cover 14>

[0111] The upper surface 14a of the upper surface cover 14 serves as a mounting surface (external mounting member placement surface 14aa) for external mounting members M such as a locator.

[0112] Therefore, the region of the upper surface 14a that is lower than the annular convex portion 14c around the annular convex portion 14c, i.e., the region of the upper surface 14a other than the annular convex portion 14c, is formed into a flat surface that is substantially the same as the reference surface except for bolts for mounting the upper surface cover 14 to the housing main body 13 and pedestals for mounting the external mounting member M, and serves as a drainage surface that is conducive to draining water from the upper surface 14a of the upper surface cover 14.

[0113] That is, in the region of the upper surface 14a other than the annular convex portion 14c, a structure such as a wall that deteriorates the drainage around the annular convex portion 14c is not formed.

[0114] Moreover, the upper surface 14a of the upper surface cover 14, i.e., the upper surface 14a of the actuator main body 10, is enlarged as an external mounting member placement surface 14aa on which external mounting members M such as a locator can be freely mounted.

[0115] More specifically, the upper surface cover 14 includes a flange portion 14e that is enlarged in a flange shape on the upper surface 14a on which the external mounting member M can be freely mounted.

[0116] In other words, the externally mounted member placement surface 14aa is the surface of the flange portion 14e that is enlarged in a flange shape at the upper part of the actuator body 10.

[0117] The flange portion 14e is provided so as to protrude in the direction of connection between the housing 12 and the pressure cylinder 11 and in the direction of connection with the housing cap 15, respectively.

[0118] In addition, as the drainage surface of the region other than the annular convex portion 14c in the upper surface 14a of the upper surface cover 14, it is not necessarily required to be a substantially flat surface as long as it is a surface that is at least conducive to drainage and does not form a protrusion surrounding the annular convex portion 14c.

[0119] For example, the drainage surface refers to a surface having the following structure: at least having a flat portion continuous from the annular convex portion 14c to the peripheral portion, or having a predetermined slope such as a decreasing height toward the peripheral portion, and the steps are also conducive to water drainage.

[0120] <Regarding the annular convex portion 14c provided on the upper surface cover 14>

[0121] An annular convex portion 14c is provided on the upper surface cover 14 on the upper surface of the housing 12 constituting the actuator body 10.

[0122] The annular convex portion 14c is a portion that protrudes from the surrounding in a region that becomes the inside of the indicator 30 in a plan view in the externally mounted member placement surface 14aa included in the upper surface of the upper surface cover 14, such that the opening portion 14bb of the through hole 14b is at a position higher than its periphery.

[0123] That is, the annular convex portion 14c is formed such that in a plan view, the region below the indicator 30 is effectively utilized, and the surface around the through hole 14b through which the shaft 20 passes is a surface higher than the upper surface of the upper surface cover 14 in other regions. In other words, the upper surface 14a of the upper surface cover 14 has a shape in which the periphery of the through hole 14b bulges higher than other regions, and the bulging portion constitutes the annular convex portion 14c.

[0124] The annular convex portion 14c is integrally formed with the upper surface cover 14.

[0125] In addition, the "integral" in this case includes, for example, not only the case where the upper surface cover 14 and the annular convex portion 14c are integrally formed by casting or machining, but also the case where they are integrally formed in a separable manner by welding, bonding, etc.

[0126] To further explain, in a plan view, the annular convex portion 14c is provided by effectively utilizing the region below the indicator 30, and further, the annular convex portion 14c is used as a pedestal, and one or more shaft auxiliary parts, namely, the thrust bearing 22, the washer 23, and the snap ring 24, are overlapped and arranged.

[0127] Such a ring-shaped convex portion 14c is provided on the upper surface 14a of the upper surface cover 14. Thus, the height of the opening portion 14bb of the through hole 14b is higher than that of other regions. In addition, the opening portion 14bb of the through hole 14b provided on the upper surface 14a of the housing 12 is disposed at a position closer to the lower surface of the indicator 30.

[0128] That is, the ring-shaped convex portion 14c functions as a waterproof wall to prevent water remaining on the upper surface 14a of the upper surface cover 14 from entering the through hole 14b, and makes the opening portion 14bb of the through hole 14b closer to the indicator 30 from a position below the indicator 30, further improving the water intrusion prevention effect of the indicator 30 as an umbrella.

[0129] In addition, the ring-shaped convex portion 14c may not be a portion having a uniform height, and unevenness may also be formed within the ring-shaped convex portion 14c.

[0130] However, even in this case, in order to exhibit a high water intrusion prevention effect, the height of the opening portion 14bb of the through hole 14b is preferably the highest position within the ring-shaped convex portion 14c.

[0131] <Regarding the indicator 30 mounted on the shaft 20>

[0132] The indicator 30 has a shaft insertion through hole 31a, and the shaft insertion through hole 31a has a shape corresponding to the cross section of the shaft 20 orthogonal to the shaft body and is inserted through the upper end portion 21 of the shaft 20. The upper end portion 21 of the shaft 20 passes through the shaft insertion through hole 31a and the indicator 30 is mounted on the boundary step portion 21c.

[0133] More specifically, the indicator 30 is made of a material such as aluminum, stainless steel, or resin, and has a top wall 31 formed with a shaft insertion through hole 31a and a peripheral side wall 32 hanging down along the outer peripheral edge surface of the top wall 31.

[0134] On the upper surface of the top wall 31, as Figure 1 shown, the following markings are noted: The markings correspond to the valve opening display plate M1 provided on the upper surface 14a of the housing 12, that is, the external mounting member placement surface 14aa, and indicate the valve opening of the valve.

[0135] In addition, in order to rotatably mount the indicator 30 together with the shaft 20 on the boundary step portion 21c, the lower end surface of the indicator 30, that is, the lower end edge 32a of the peripheral side wall 32 of the indicator 30, is set at a height away from the upper surface 14a of the upper surface cover 14, and the upper surface 14a is lower than the upper surface 14d of the ring-shaped convex portion 14c.

[0136] Further, the relative positional relationship in the height direction between the lower end edge 32a of the peripheral side wall 32 of the indicator 30 and the opening portion 14bb of the through hole 14b is set such that the lower end edge 32a of the peripheral side wall 32 is located lower than the opening portion 14bb of the through hole 14b.

[0137] Therefore, as Figure 2B shown, the water intrusion path from the gap G between the indicator 30 and the upper surface 14a of the housing 12 to the through hole 14b becomes a complex and intertwined structure with a bent shape due to the peripheral side wall 32 of the indicator 30 and the annular convex portion 14c.

[0138] In addition, the indicator 30 is such that the shaft insertion through hole 31a is inserted through the prism portion 21a of the shaft 20, and is seated on the boundary step portion 21c between the prism portion 21a and the cylindrical portion 21b of the shaft 20 and is mounted on the upper end portion 21 of the shaft 20.

[0139] <Regarding the installation process of the indicator 30>

[0140] When installing such an indicator 30 on the boundary step portion 21c of the upper end portion 21 of the shaft 20, as Figure 4A shown, the indicator 30 is arranged at the position of the upper end portion 21 of the shaft 20 when viewed from above, the shaft insertion through hole 31a is set to face the angle of the prism portion 21a of the shaft 20, and the indicator 30 is lowered while inserting the prism portion 21a into the shaft insertion through hole 31a.

[0141] Then, as Figure 4B shown, after the indicator 30 is lowered along the prism portion 21a until the lower surface of the top wall 31 touches the boundary step portion 21c of the shaft 20, the snap ring 33 is fixed to the shaft 20 from the upper surface side of the indicator 30.

[0142] Thereby, the indicator 30 is installed in a state of being highly accurately positioned in the height direction with respect to the upper end portion 21 of the shaft 20.

[0143] <Effects of Embodiment 1>

[0144] As described above, according to the valve actuator 1 of Embodiment 1 of the present invention, in the external mounting member placement surface 14aa, in the region that becomes the inside of the indicator 30 when viewed from above, an annular convex portion 14c that protrudes more than the surroundings is integrally provided with the external mounting member placement surface 14aa, so that the opening portion 14bb of the through hole 14b is located at a position higher than its periphery.

[0145] Thus, according to the invention of Embodiment 1 of the present invention, by means of the indicator 30 mounted on the shaft 20, it is possible to prevent rainwater or the like from directly falling from above onto the opening portion 14bb of the through-hole 14b, blocking the intrusion of water. Moreover, with respect to the water remaining on the external mounting member placement surface 14aa, that is, the water remaining on the upper surface of the actuator body 10, it is also difficult for the water to reach the opening portion 14bb of the through-hole 14b which is at a position higher than the surroundings by means of the annular convex portion 14c. Therefore, the intrusion of water into the through-hole 14b is blocked.

[0146] Therefore, according to the invention of Embodiment 1 of the present invention, it is possible to improve the waterproof function around the shaft 20 by means of the annular convex portion 14c with a simple structure without affecting the installation space of the external mounting member on the upper part of the actuator body 10. As a result, the waterproof performance around the shaft can be improved with a simple structure.

[0147] In addition, for the valve actuator 1 according to Embodiment 1 of the present invention, the external mounting member placement surface 14aa is a surface including the flange portion 14e that is flange-shaped and enlarged at the upper part of the actuator body 10. Thus, it is easy to adjust the area of the external mounting member placement surface 14aa for mounting the external mounting member M, that is, the upper surface of the actuator body 10, to a size that conforms to the specifications. Moreover, with respect to the water remaining on the upper surface enlarged by means of the flange portion 14e, it is also possible to effectively prevent the intrusion of the water into the through-hole 14b by means of the annular convex portion 14c.

[0148] In addition, for the valve actuator 1 according to Embodiment 1 of the present invention, the external mounting member placement surface 14aa is a drainage surface that is lower than the annular convex portion 14c in the region outside the annular convex portion 14c. Thus, there is no structure such as a wall around the annular convex portion 14c that obstructs drainage, and the drainage property is improved. Therefore, it is difficult for water to remain around the annular convex portion 14c. As a result, the waterproof performance around the shaft 20 can be improved.

[0149] In addition, for the valve actuator 1 according to Embodiment 1 of the present invention, there are a thrust bearing 22, a washer 23, and a snap ring 24 as one or more shaft auxiliary parts for rotatably holding the shaft 20 in a predetermined position with respect to the actuator body 10. These shaft auxiliary parts 22, 23, 24 are provided above the annular convex portion 14c and below the indicator 30. Thus, by means of the annular convex portion 14c, the intrusion of the water remaining on the external mounting member placement surface 14aa, that is, the water remaining on the upper surface 14a of the actuator body 10, that is, the pressure cylinder 11, is blocked. Therefore, it is possible to prevent the attachment of water to the shaft auxiliary parts 22, 23, 24 which are located above the annular convex portion 14c, and it is possible to prevent water from penetrating into the actuator body along the shaft auxiliary parts 22, 23, 24 through the shaft 20 and the through-hole 14b.

[0150] In addition, in the valve actuator 1 according to Embodiment 1 of the present invention, thrust bearings 22, washers 23, and snap rings 24 as shaft auxiliary parts are arranged in a region inside the indicator 30 when viewed from above. Thus, the indicator 30 mounted on the shaft 20 functions as an umbrella, capable of preventing rain or the like from falling onto the shaft auxiliary parts 22, 23, and 24, and preventing water from penetrating through the shaft auxiliary parts 22, 23, and 24 into the pressure cylinder 11 through the shaft 20 and the through hole 14b, that is, into the actuator main body 10.

[0151] In addition, in the valve actuator 1 according to Embodiment 1 of the present invention, the indicator 30 has a shaft insertion hole 31a having a shape corresponding to a cross-section orthogonal to the shaft body of the shaft 20. The upper end portion of the shaft 20 passes through the shaft insertion hole 31a, and the indicator 30 is mounted on the shaft 20. The indicator 30 has a top wall 31 in which the shaft insertion hole 31a is formed, and a peripheral side wall 32 that hangs down along the outer peripheral surface of the top wall 31. The relative positional relationship in the height direction between the lower end edge 32a of the peripheral side wall 32 and the opening portion 14bb of the through hole 14b is set such that the lower end edge 32a of the peripheral side wall 32 is lower than the opening portion 14bb of the through hole 14b.

[0152] Thus, in the valve actuator 1 according to Embodiment 1 of the present invention, the gap between the indicator 30 and the upper surface 14a of the actuator main body 10, that is, the upper surface cover 14, has a complex and interleaved shape, and it is more difficult for the water remaining on the upper surface 14a of the actuator main body 10 to penetrate into the through hole 14b.

[0153] Therefore, in the valve actuator 1 according to Embodiment 1 of the present invention, the waterproof function around the shaft can be further improved.

[0154] In addition, in the valve actuator 1 according to Embodiment 1 of the present invention, the shaft 20 has a prism portion 21a and a cylindrical portion 21b. The cylindrical portion 21b is below the prism portion 21a, and the diameter of the cross-section is larger than the distance between the opposite side surfaces of the prism portion 21a. The shaft insertion hole 31a of the indicator 30 has a shape corresponding to the outer shape of the prism portion 21a. The indicator 30 is such that the shaft insertion hole 31a is inserted through the prism portion 21a and the lower surface of the top wall 31 is seated on the boundary step portion 21c between the prism portion 21a and the cylindrical portion 21b, and thus is mounted on the shaft 20.

[0155] Thus, in the valve actuator 1 according to Embodiment 1 of the present invention, when the indicator 30 is mounted on the shaft 20, the indicator 30 is positioned in the mounting height direction by means of the boundary step portion 21c.

[0156] Therefore, in the valve actuator 1 according to Embodiment 1 of the present invention, the indicator 30 can be positioned with high precision in the height direction with respect to the upper end portion of the shaft 20, and can be easily mounted.

[0157] In addition, in the valve actuator 1 according to Embodiment 1 of the present invention, the lower end edge 32a of the peripheral side wall 32 of the indicator 30 is set at a height lower than the opening portion 14bb of the through hole 14b and away from the upper surface 14a of the actuator main body 10, that is, the upper surface cover 14. Thus, even if water accidentally enters the indicator 30, the water in the indicator 30 flows out from the gap G between the lower end edge 32a of the indicator 30 and the upper surface 14a of the actuator main body 10, and the waterproof function around the shaft 20 can be further improved.

[0158] The above has described Embodiment 1 of the present disclosure, but the present disclosure is not limited to the above-described Embodiment 1, and various changes can be made without departing from its gist.

[0159] For example, in the above-described Embodiment 1, the indicator 30 is exemplified as the shaft mounting member mounted on the shaft 20, but other shaft mounting members can also be mounted on the shaft 20.

[0160] In addition, when the external mounting member is a limit switch or a speed controller, the limit switch or the speed controller can be mounted on the shaft 20 by using the above-described linear groove 21d and internal thread 21e.

[0161] In addition, these external mounting members can also be fixed to a predetermined pedestal or the like provided on the external mounting member placement surface 14aa.

[0162] In addition, in the above-described Embodiment 1, the structure in which the indicator 30 has the top wall 31 and the peripheral side wall 32 is exemplified, but it is not limited thereto, and it can also be as Figure 5A shown, the indicator 30 is a structure without the peripheral side wall 32.

[0163] Even if the indicator 30 is a structure without the peripheral side wall 32, when the indicator 30 prevents water from invading the through hole 12b from above and the water remaining on the upper surface 14a of the actuator main body 10 is about to flow into the gap G, it can be blocked by the annular convex portion 14c to prevent water from invading the through hole 14b, and the waterproof function around the shaft 20 can be improved without affecting the space of the external mounting member placement surface 14aa on the upper surface 14a of the actuator main body 10.

[0164] In addition, the indicator 30 can also be as Figure 5B shown, and an inclined surface 31b is formed on the upper surface of the top wall 31. By forming the inclined surface 31b on the top wall 31 in this way, it is possible to prevent water from remaining on the top wall 31 of the indicator 30.

[0165] It should be considered that each of the disclosed Embodiments 1 is illustrative and not restrictive in all respects. The above-described embodiments can be omitted, replaced, and changed in various ways without departing from the appended claims and their gist.

[0166] (Embodiment 2)

[0167] Use Figures 6 - 13 The shaft mounting member of Embodiment 2 and the valve actuator including the shaft mounting member of Embodiment 2 will be described in detail.

[0168] In this Embodiment 2, the description of the same structure as that of Embodiment 1 is omitted.

[0169] Figure 6 Fig. is an exploded perspective view showing an exploded view of the indicator 100 of the valve actuator 2 of Embodiment 2 of the present invention. Figure 7 Fig. is a perspective view around the shaft 20 of the valve actuator 2. Figure 8 Fig. is a top view around the shaft 20 of the valve actuator 2. Figure 9A Is Figure 8 A cross-sectional view taken along line IV-IV of the valve actuator 2 shown in Fig. Figure 9B Is Figure 9A An enlarged view around the upper end portion 21 of the shaft 20 shown in Fig. Figure 10A Is Figure 8 A cross-sectional view taken along line V(a)-V(a) around the upper end portion 21 of the shaft 20 of the valve actuator 2 shown in Fig. Figure 10B Is Figure 8 A cross-sectional view taken along line V(b)-V(b) around the upper end portion 21 of the shaft 20 of the valve actuator 2 shown in Fig. Figure 11 Fig. is a diagram for explaining a rotation conversion mechanism 60 that converts the reciprocating motion of the piston 41 into the rotational motion of the shaft 20. Figure 12 Fig. is a perspective view of the indicator 100. Figure 13 Fig. is a diagram for explaining the dimension of the width of the upper end surface 120a of the water retention prevention portion 120.

[0170] In addition, the present disclosure is not limited by the embodiments described below. In addition, it should be noted that the drawings are schematic, and the dimensional relationships between the elements, the ratios of the elements, etc. are sometimes different from the actual ones. Furthermore, there are sometimes parts in the drawings where the dimensional relationships and ratios between each other are different.

[0171] An indicator 100 as a shaft mounting member of Embodiment 2 of the present invention is mounted on the shaft 20 of the valve actuator 2.

[0172] Hereinafter, the indicator 100 will be described in conjunction with the description of the overall structure of the valve actuator 2.

[0173] The valve actuator 2 is a gas-driven actuator, and includes an actuator main body 510, a shaft 20 whose upper end portion protrudes from the upper portion of the actuator main body 510, and an indicator 100 mounted on the shaft 20 as a shaft mounting member.

[0174] <Regarding the actuator body 510>

[0175] The actuator body 510 forms a space inside for sucking and discharging gas through two gas ports AP1 and AP2 and for the reciprocating movement of the piston 41. A rotary conversion mechanism 60 is provided inside. The rotary conversion mechanism 60 converts the reciprocating movement of the piston 41 into a rotary movement and transmits it to the shaft 20 as an output shaft.

[0176] The actuator body 510 has an upper surface cover 14 that closes the upper surface opening in a state of protruding in a part of a flange shape. Various external mounting parts M can be placed on the enlarged upper surface of the upper surface cover 14 including the flange part.

[0177] The rotary conversion mechanism 60 provided in the actuator body 510 adopts a so-called anti-rotation yoke type mechanism. As shown in Figure 11 the rotary conversion mechanism 60 has: an anti-rotation yoke 50 that engages with a pin P protruding in the radially outer direction of a piston rod 42 having a piston 41 at one end; and a shaft 20 that is connected to the anti-rotation yoke 50 by a key (not shown) and rotates and drives as an output shaft.

[0178] That is, the rotary conversion mechanism 60 converts the reciprocating movement of the piston 41 into the rotary movement of the shaft 20 via the anti-rotation yoke 50.

[0179] <Regarding the shaft 20>

[0180] One end below the shaft 20 is connected to a valve stem (not shown) of a valve, and the upper end portion of the other end passes through a through hole 14b formed in the upper surface cover 14 constituting the upper surface of the actuator body 510 and protrudes from the inside to the outside of the actuator body 510.

[0181] And, as shown in Figure 11 the upper end portion 21 of the shaft 20 has a prism portion 21a and a cylindrical portion 21b. The diameter of the cross section of the cylindrical portion 21b is larger than the distance between the opposite side surfaces of the prism portion and is provided below the prism portion 21a.

[0182] The boundary step portion 21c between the prism portion 21a and the cylindrical portion 21b is a portion for seating a part of the indicator 100 to mount the indicator 100.

[0183] On the cylindrical portion 21b of the shaft 20, a plurality of shaft auxiliary parts are provided for rotatably holding the shaft 20 at a predetermined position in the actuator body 510.

[0184] In the second embodiment, a thrust bearing 22, a washer 23, and a C-shaped snap ring 24 are provided as the shaft auxiliary parts.

[0185] The thrust bearing 22 is overlapped and installed on the upper surface of the actuator body 510, the washer 23 is overlapped and installed on the thrust bearing 22, and further, by means of the snap ring 24 overlapped and installed on the washer 23, the shaft 20 is rotatably held relative to the actuator body 510 in such a manner that it will not fall into the actuator body 510.

[0186] In addition, the shaft auxiliary parts are not limited to the thrust bearing 22, the washer 23 and the snap ring 24, and other parts can also be used as long as they assist in rotatably holding the shaft 20 at a predetermined position relative to the actuator body 510.

[0187] The prism part 21a of the shaft 20 is a quadrangular prism, and linear grooves 21d for mounting various external mounting parts are provided on the upper surface, that is, the upper end surface of the shaft 20.

[0188] The linear grooves 21d are set to have a predetermined shape and size conforming to the NAMUR standard, ensuring the interchangeability of the mounting with various external mounting parts other than the indicator 100.

[0189] Internal threads 21e for mounting external mounting parts are provided at the central positions of the linear grooves 21d, and predetermined external mounting parts can be mounted by using the internal threads 21e and the like.

[0190] In addition, in the prism part 21a of the shaft 20, as Figure 11 shown, a fixing groove 21h for fixing the C-shaped snap ring 33 is provided. The C-shaped snap ring 33 is an annular fixing part for fixing the indicator 100 to the prism part 21a of the shaft 20.

[0191] Here, the snap ring 33 is used as the fixing part because the height of the shaft 20 protruding from the upper part of the actuator body 510 is determined according to specifications and the like.

[0192] That is, it is preferable to use an annular fixing part such as the snap ring 33 that suppresses the height dimension and stably fixes to the shaft 20 in a manner surrounding the shaft 20 as the fixing part for the shaft 20 protruding from the upper part of the actuator body 510.

[0193] <Regarding the indicator 100>

[0194] The indicator 100 is a shaft mounting part that is mounted on the prism part 21a of the shaft 20 protruding from the upper part of the actuator body 510 and whose upper surface extends in the radial outer direction of the shaft 20.

[0195] The indicator 100 has a shaft insertion through hole 110c, and the shaft insertion through hole 110c has a shape corresponding to the cross section of the prism part 21a (columnar part) of the shaft 20, that is, the cross section of the shaft 20 orthogonal to the shaft body, and is inserted through by the upper end part 21 of the shaft 20.

[0196] The shaft insertion through-hole 110c is a rectangular hole corresponding to the prism portion 21a of the shaft 20 and is adjusted to a size into which the prism portion 21a is inserted.

[0197] The indicator 100 is installed on the prism portion 21a of the shaft 20 by passing the upper end portion 21 of the shaft 20 through the shaft insertion through-hole 110c so that the inner surface seats on the boundary step portion 21c and making the retaining ring 33 abut against the upper surface.

[0198] More specifically, the indicator 100 is made of a material such as aluminum, stainless steel, or resin, and has a top wall 110 in which the shaft insertion through-hole 110c is formed, and a peripheral side wall 140 that hangs down along the outer peripheral edge 110b of the top wall 110.

[0199] In addition, the indicator 100 is provided near the upper surface of the actuator body 510 through the side peripheral wall 140 to effectively prevent rainwater, etc. from falling near the shaft 20.

[0200] Furthermore, on the upper surface of the actuator body 510, the periphery of the shaft 20 is raised, and correspondingly, it is extremely difficult for water to invade from the shaft 20 portion. However, the indicator 100 does not necessarily have to have the side peripheral wall 140, and it can also exert the effect of preventing water from invading from the shaft 20 by having a water retention prevention portion 120 described later.

[0201] As Figures 6 - 8 shown, on the upper surface of the top wall 110, an indicator mark 151 is provided that corresponds to the valve opening display plate M1 provided on the upper surface of the actuator body 510 and indicates the valve opening of the valve.

[0202] In addition, in this embodiment, the indicator mark 151 is provided on the top wall 110 that constitutes the upper surface of the indicator 100 to the peripheral side wall 140 that constitutes the side surface at a circumferential position corresponding to the corner portion 21f of the prism portion 21a of the shaft 20.

[0203] That is, the indicator mark 151 is arranged at a position corresponding to the corner portion 21f of the shaft 20 where water is difficult to retain.

[0204] In this embodiment, at the indicator 100, insertion recesses 150 for inserting and installing the indicator mark 151 are provided at three positions corresponding to the three-way valve, but the number of insertion recesses 150 can be appropriately set according to the type of valve.

[0205] Such an indicator 100 is provided with a water retention prevention portion 120 and an enlarged flat portion 130.

[0206] <Regarding the water retention prevention portion 120 of the indicator 100>

[0207] The water retention prevention part 120 is arranged in the area of the upper surface 110a of each planar side surface 21g of the prism part 21a close to the shaft 20, and is provided with an upper end surface 120a that suppresses the plane to be smaller, and a water guiding inclined surface 120b that slopes downward is formed from the upper end surface 120a toward the radially outer direction of the shaft 20 at an inclination angle larger than that of the area of the upper surface 110a connected to the outer peripheral edge 110b side.

[0208] The water retention prevention part 120 is arranged such that the upper end surface 120a is arranged in the area of the four planar side surfaces 21g of the prism part 21a with a quadrilateral cross-section close to the shaft 20.

[0209] In addition, in the present embodiment, as Figure 9B shown, the water guiding inclined surface 120b is a gentle downward inclined surface with an inclination angle smaller than that of the water guiding inclined surface 120b in the area of the upper surface 110a connected to the outer peripheral edge 110b side until the outer peripheral edge 110b.

[0210] That is, the indicator 100 is an inclined surface that slopes downward in the radially outer direction of the shaft 20, which is formed by a water guiding inclined surface 120b with a steeper slope around the shaft 20 and a gentle inclined surface continuous with the water guiding inclined surface 120b in the radially outer direction of the shaft 20, and is continuously arranged from around the shaft 20 to the outer peripheral edge.

[0211] In addition, the area of the upper surface 110a connected to the outer peripheral edge 110b side of the water guiding inclined surface 120b may also be a non-inclined plane.

[0212] Each water retention prevention part 120, as Figure 12 shown, has a shaft approaching surface 120c, the above-mentioned planar upper end surface 120a, and a water guiding inclined surface 120b. The shaft approaching surface 120c forms one surface of the inner surface of the shaft insertion hole 110c, is close to one planar side surface 21g of the prism part 21a of the shaft 20 or is arranged in parallel with the planar side surface 21g with a slight gap, and the water guiding inclined surface 120b slopes downward from the upper end surface 120a toward the outer peripheral edge 110b side of the indicator 100.

[0213] Moreover, the upper end surface 120a of the water retention prevention part 120 is adjusted to suppress the width in the radially outer direction of the shaft 20 to a smaller size.

[0214] That is, the upper end surface 120a of the water retention prevention part 120 is a surface that is arranged close to the planar side surface 21g extending in a substantially vertical direction of the prism part 21a of the shaft 20, forms a corner A1 that intersects the planar side surface 21g of the prism part 21a at a substantially right angle, and is formed to suppress the width to be smaller.

[0215] Therefore, in the valve actuator 2, an inward corner A1 is formed by the planar side surface 21g of the shaft 20 and the upper end surface 120a of the water retention prevention portion 120, and the contact area of water with respect to this corner A1 is suppressed to be small.

[0216] Moreover, the water guiding inclined surface 120b is connected at its lower end to a region that extends downward at an inclination angle smaller than that of the water guiding inclined surface 120b and reaches the upper surface 110a of the outer peripheral edge 110b of the indicator 100.

[0217] Regarding the inward corner A2 formed by the region of the water guiding inclined surface 120b and the upper surface 110a connected thereto (refer to Figure 10A , Figure 12 ), since it is an obtuse angle, the contact area of water is suppressed to be small.

[0218] <Regarding the enlarged planar portion 130 of the indicator 100>

[0219] The enlarged planar portion 130 is a portion where an upper end surface 130a is formed in a region of the upper surface 110a close to each corner 21f of the prismatic portion 21a of the shaft 20, and the upper end surface 130a is composed of a plane whose width is enlarged in the radially outer direction of the shaft 20 compared to the upper end surface 120a of the water retention prevention portion 120.

[0220] The upper end surface 130a of this enlarged planar portion 130 is a surface against which a retaining ring 33, which is an annular fixing member for fixing the indicator 100 to the shaft 20, abuts, and is set to be at the same height as the upper end surface 120a of the water retention prevention portion 120.

[0221] This enlarged planar portion 130 is set such that the width in the radially outer direction of the shaft 20 is at least larger than the upper end surface 120a of the water retention prevention portion 120, and the retaining ring 33 can abut stably.

[0222] In addition, the upper end surface 130a of the enlarged planar portion 130 is set to have a width at an inner position spaced apart from the outer peripheral edge 110b of the indicator 100, and an insertion recess 150 for the indicator mark 151 is provided in a portion in the radially outer direction of this enlarged plane 130 and at the outer peripheral edge 110b.

[0223] Furthermore, the upper end surface 130a of the enlarged planar portion 130 can also be set to be higher than the upper end surface 120a of the water retention prevention portion 120 so that the retaining ring 33 does not abut against the upper end surface 120a of the water retention prevention portion 120 and only abuts against the upper end surface 130a of the enlarged planar portion 130.

[0224] In addition, when the indicator 100 is fixed to the shaft 20 with the snap ring 33 abutted against the enlarged flat portion 130, the width of the upper end surface 120a of the water retention prevention portion 120 in the radially outer direction of the shaft 20 is set to be smaller than the maximum width E in the radially outer direction of the gap between the inner circumferential surface of the snap ring 33 and the planar side surface 21g of the prismatic portion 21a of the shaft 20 (see Figure 8 , Figure 10A ).

[0225] Thus, a gap for discharging downward is formed between the shaft 20 and the snap ring 33, so that water is configured not to stay and flows to the water guiding inclined surface 120b and is discharged to the upper surface 110a.

[0226] Here, by using Figure 13 , the dimension of the width of the upper end surface 120a of the required water retention prevention portion 120 is described based on the dimensions of the snap ring 33, which is a substantially annular fixing member, and the prismatic portion 21a of the shaft 20.

[0227] In addition, Figure 13 simplifies the representation of the snap ring 33 and the prismatic portion 21a, and the snap ring 33 is represented as an annular member.

[0228] The markings of the dimensions of each part are defined as follows.

[0229] C: Inner diameter of the snap ring 33

[0230] D: Width of the planar side surface 21g of the prismatic portion 21a

[0231] L: Width of the diagonal of the prismatic portion

[0232] In addition, since the snap ring 33 is fixed to the fixing groove 21h of the prismatic portion 21a, the following size relationship of formula (a) holds for the inner diameter C of the snap ring 33 and the diagonal width L of the prismatic portion 21a.

[0233] C < L ··· (a)

[0234] And the maximum width E of the gap between the inner diameter C of the snap ring 33 and the planar side surface 21g of the prismatic portion 21a is as follows in formula (b).

[0235] E = (C - D) / 2 ··· (b)

[0236] Therefore, the upper limit of the width W of the upper end surface 120a of the water retention prevention portion 120 is determined according to the following formula (c).

[0237] W < (C - D) / 2 ··· (c)

[0238] Wherein, C < L.

[0239] By setting the upper limit of the width W of the upper end surface 120a in this way, there is a region of the upper surface that is lower than the upper end surface 120a of the water retention prevention portion 120 between the inner peripheral surface 33a of the snap ring 33 and the planar side surface 21g of the prism portion 21a, and water easily flows from this region to the region of the upper surface 110a outside the snap ring 33.

[0240] <Regarding the installation process of the indicator 1>

[0241] When installing such an indicator 100 on the shaft 20, the indicator 100 is arranged at the position of the upper end portion 21 of the shaft 20 when viewed from above, so that the shaft insertion hole 110c is in the direction corresponding to the corner portion 21f of the prism portion 21a of the shaft 20, and the indicator 100 is lowered while inserting the prism portion 21a into the shaft insertion hole 110c.

[0242] Then, after the indicator 100 is lowered along the prism portion 21a until the lower surface of the top wall 110 of the indicator 100 abuts against the boundary step portion 21c of the shaft 20, the snap ring 33 is passed through the prism portion 21a of the shaft 20 from the upper surface side of the indicator 100 and abutted against the enlarged flat portion 130 of the indicator 100, thereby fixing the indicator 100 to the prism portion 21a of the shaft 20.

[0243] The snap ring 33 in contact with the enlarged flat portion 130 is embedded in the fixing groove 21h provided in the prism portion 21a and fixed to the shaft 20, whereby the indicator 100 is clamped and fixed from the upper surface side between the boundary step portion 21c.

[0244] In addition, when the snap ring 33 is moved while passing through the prism portion 21a of the shaft 20, a tool such as pliers is inserted into the hole 34a of the lug 34 of the snap ring 33 and moved.

[0245] Here, if the snap ring 33 is installed on the shaft 20 with the orientation of the lug 34 facing the water retention prevention portion 120, the snap ring 33 is in a state where a gap is ensured between the lug 34 and the upper surface 110a of the indicator 100 at the installation completion position in contact with the enlarged flat portion 130, so that a tool such as pliers is not easily interfered with the upper surface 110a of the indicator 100, and the installation operation of the snap ring 33 becomes easy.

[0246] In addition, regarding the case of removing the snap ring 33 from the shaft 20, the tool is not easily interfered with the upper surface 110a of the indicator 100 even below the lug 34, so the operation becomes easy.

[0247] <Effects of Embodiment 2>

[0248] As described above, in the indicator 100 according to Embodiment 2 of the present invention, a water retention prevention portion 120 is provided. The water retention prevention portion 120 is arranged in a region of the upper surface 110a close to the planar side surface 21g of the prism portion 21a of the shaft 20, and has an upper end surface 120a that suppresses the plane to be smaller. A water guiding inclined surface 120b is formed on the outer peripheral edge 110b side in the radial outer direction of the shaft 20 from the upper end surface 120a. The water guiding inclined surface 120b inclines downward at an inclination angle larger than that of the connected region of the upper surface 110a.

[0249] Thus, in the region of the upper surface 110a of the indicator 100 close to the planar side surface 21g of the shaft 20, the upper end surface 120a of the water retention prevention portion 120 that suppresses the plane to be smaller is arranged. By means of the upper end surface 120a that suppresses the plane to be smaller, the contact area of water at the inward corner formed by the intersection of the planar side surface 21g around the prism portion 21a of the shaft 20 and the upper surface 110a of the indicator 100 is suppressed to be smaller.

[0250] Moreover, the water that is difficult to stay around the prism portion 122 of the shaft 20 flows along the downward-inclined inclined surface of the water retention prevention portion 120 to the outer peripheral edge 110b.

[0251] Therefore, water retention around the shaft 20 is prevented, and as a result, the waterproof performance around the shaft 20 can be improved.

[0252] In addition, the water guiding inclined surface 120b with a large inclination angle is not arranged in the entire region in the radial outer direction of the shaft 20 on the upper surface 110a of the indicator 100 but in a part, so that the water retention prevention effect around the shaft 20 can be exerted and the increase in the height dimension can be suppressed to be smaller.

[0253] Furthermore, in the indicator 100 according to the embodiment of the present invention, in the region of the upper surface 110a close to each corner portion 21f of the prism portion 21a of the shaft 20, an enlarged plane portion 130 is provided. The enlarged plane portion 130 has an upper end surface 130a formed by a plane whose width is enlarged in the radial outer direction of the shaft 20 compared with the upper end surface 120a of the water retention prevention portion 120. Thus, in the region of each outward corner close to the prism portion 21a of the shaft 20 where water is difficult to stay, a surface for various components to abut is ensured, so that various components can be stably abutted and arranged on the upper surface of the indicator 100 while preventing water retention around the shaft 20.

[0254] In addition, in the case where the indicator 100 according to an embodiment of the present invention is fixed to the shaft 20 by bringing the annular fixing member, i.e., the snap ring 33, into contact with the enlarged flat portion 130, the width in the radially outer direction of the shaft 20 of the upper end surface 120a of the water retention prevention portion 120 is set to be smaller than the maximum width in the radially outer direction of the gap between the inner peripheral surface 33a of the snap ring 33 and the planar side surface 21g of the prismatic portion 21a of the shaft 20. Thus, even if water intrudes between the planar side surface 21g of the prismatic portion 21a of the shaft 20 and the inner peripheral surface 33a of the snap ring 33, the water flows from the upper end surface 120a of the water retention prevention portion 120 to the outer peripheral edge 110b through the gap provided between the water retention prevention portion 120 and the snap ring 33.

[0255] Therefore, the indicator 100 can be stably fixed to the prismatic portion 21a of the shaft 20 by means of the snap ring 33, and the water intruding between the planar side surface 21g of the prismatic portion 21a and the inner peripheral surface 33a of the snap ring 33 can be made to flow toward the outer peripheral edge 110b of the indicator 100.

[0256] In addition, in the valve actuator 2 according to an embodiment of the present invention, the indicator 100 is mounted on the columnar portion 21a of the shaft 20 that is connected to the valve stem of the valve and protrudes from the upper portion of the actuator body 510. The columnar portion 21a has at least one planar side surface 21g on the circumferential side surface and a corner portion 21f formed by side surfaces intersecting the planar side surface 21g.

[0257] Thus, in the region of the upper surface close to the planar side surface 21g of the shaft 20, the upper end surface 120a of the water retention prevention portion 120 that suppresses the plane to be smaller is arranged. By means of the upper end surface 120a that suppresses the plane to be smaller, the contact area of the water at the inward corner formed by the intersection of the planar side surface 21g around the columnar portion 21a of the shaft 20 and the upper surface of the indicator 100 is suppressed to be smaller.

[0258] Moreover, the water that is difficult to stay around the columnar portion 21a of the shaft 20 flows along the downwardly inclined surface of the water retention prevention portion 120 to the outer peripheral edge.

[0259] Therefore, water retention around the shaft 20 can be prevented. As a result, the waterproof performance around the shaft 20 can be improved.

[0260] <Modification Example 1>

[0261] Here, a reference is made to Figure 14 to describe Modification Example 1 of the indicator 100 of Embodiment 2.

[0262] Figure 14 is a diagram showing Modification Example 1 of the indicator 100.

[0263] In addition, in Modification 1, the same reference numerals are assigned to the same parts as in Embodiment 2, and redundant explanations are omitted.

[0264] The difference between the indicator 200 of this Modification 1 and the indicator 100 of Embodiment 2 is that the enlarged planar portion 230 of the abutting retaining ring 33 forms an upper end surface 230a with a constant height from the region of the upper surface 110a close to each corner portion 21f of the prism portion 21a of the shaft 20 to the outer peripheral edge 110b.

[0265] According to the indicator 200 of this Modification 1, the surface of the retaining ring 33 that abuts against the shaft 20 can be further enlarged in the radially outer direction of the shaft 20, so that the retaining ring 33 can be more stably abutted and arranged.

[0266] <Modification 2>

[0267] Next, Figure 15 Modification 2 of the indicator 100 of Embodiment 2 will be described.

[0268] FIG. 10 is a diagram showing Modification 2 of the indicator 100.

[0269] In addition, in Modification 2, the same reference numerals are assigned to the same parts as in Embodiment 2, and redundant explanations are omitted.

[0270] The difference between the indicator 300 of this Modification 2 and the indicator of Embodiment 2 is that a planar upper end surface is not provided in the water retention prevention portion 320, and the upper end 320a of the water guiding inclined surface 320b is arranged close to each planar side surface 21g of the prism portion 21a of the shaft 20.

[0271] According to the indicator 300 of this Modification 2, an inclined surface is formed that slopes downward from the upper end 320a of the water retention prevention portion 320, so that the inner angle A3 formed by the intersection of the planar side surface 21g extending in a substantially vertical direction of the prism portion 21a of the shaft 20 and the water guiding inclined surface 320b of the water retention prevention portion 320 is an obtuse angle. Therefore, at this angle A3, the contact area of water is suppressed to be small, preventing water from staying around the shaft 20. As a result, the waterproof performance around the shaft 20 can be improved.

[0272] <Modification 3>

[0273] Next, Figure 16 Modification 3 of the indicator of the embodiment will be described.

[0274] Figure 16 is a diagram showing Modification 3 of the indicator 100.

[0275] In addition, in Modification 3, the same reference numerals are assigned to the same parts as in Embodiment 2, and redundant explanations are omitted.

[0276] The indicator 400 of the third modification example is different from the indicator 100 of the second embodiment in that the enlarged flat portion 130 is not provided.

[0277] According to the indicator 400 of the third modification example, an upper end surface 420a that suppresses the plane of the water retention prevention portion 420 to be small is formed in all circumferential regions of the prismatic portion 21a of the shaft 20.

[0278] In addition, the indicator 400 of the third modification example is fixed to the shaft 20 without using the snap ring 33, for example, by providing a locking structure (not shown) inside instead of the snap ring 33.

[0279] The embodiments of the present disclosure have been described above, but the present disclosure is not limited to the above-described first embodiment, and various changes can be made without departing from the gist thereof.

[0280] For example, in the above-described second embodiment, the indicator 100 is illustrated as being mounted on the prismatic portion 21a of the shaft 20 of the valve actuator 2, but the indicator 100 may also be Figure 17 as shown, mounted on the prismatic portion 622 of the valve stem 620, which is a shaft protruding from the upper portion of the valve body 610 of the valve 600.

[0281] In addition, in the above-described embodiments, the indicator 100 is illustrated as being mounted on the prismatic portion 21a of the shaft 20, but the shaft mounting member mounted on the shaft 20 is not limited to the indicator 100. That is, as long as it is a shaft mounting member provided with the water retention prevention portion 120, other shaft mounting members other than the indicator 100 may be mounted on the prismatic portion 21a of the shaft 20.

[0282] For example, a water retention prevention portion 120 may be provided in a cam mounted on the shaft in a manner of pressing a limit switch or a detection body of a proximity switch, and the same may be mounted on the prismatic portion 21a of the shaft 20 as a shaft mounting member.

[0283] In addition, in the above-described embodiments, the indicator 100 is illustrated as being mounted on the prismatic portion 21a of the shaft 20, but is not limited thereto. The portion where the indicator 100 is mounted may be a columnar portion of the shaft 20 having a corner portion formed by at least one planar side surface and a side surface intersecting the planar side surface on the circumferential side surface. For example, the columnar portion of the shaft 20 may be hexagonal prism-shaped, octagonal prism-shaped, or may have a structure having two planar side wall surfaces arranged in parallel in the width direction. Furthermore, it may have only one planar side wall surface.

[0284] It should be considered that each of the embodiments disclosed this time is illustrative and not restrictive in all aspects. The above-described embodiments can be omitted, replaced, and changed in various ways without departing from the appended claims and their gist.

[0285] Description of Reference Numerals

[0286] 1, 2 Valve actuator

[0287] 10 Actuator body

[0288] 11 Pressure cylinder (actuator body)

[0289] 12 Shell (actuator body)

[0290] 13 Shell body (actuator body)

[0291] 14 Upper cover (actuator body)

[0292] 14a Upper surface

[0293] 14aa External mounting surface

[0294] 14b Through hole

[0295] 14bb opening

[0296] 14c Annular convex part

[0297] 14d Upper surface of convex part

[0298] 14e Flange

[0299] 15 Shell cap (actuator body)

[0300] 510 Actuator body (valve actuator body)

[0301] 20 Axis

[0302] 21 Upper end

[0303] 21a Prismatic part (columnar part)

[0304] 21b Cylindrical part

[0305] 21c Boundary step section

[0306] 21d Linear slot

[0307] 21e Internal thread

[0308] 21f Corner

[0309] 21g Flat side

[0310] 21h fixed slot

[0311] 22 Thrust bearing (shaft auxiliary part)

[0312] 23 Washer

[0313] 24 Retaining Ring

[0314] 30 Indicator (Shaft Mounting Part)

[0315] 100, 200, 300, 400 Indicator (Shaft Mounting Part)

[0316] 31 Top Wall

[0317] 110 Top Wall

[0318] 31a Axle Insert Through-Hole

[0319] 110c Axle Insert Through-Hole

[0320] 31b Inclined Surface

[0321] 32 Peripheral Side Wall

[0322] 32a Lower End Edge

[0323] 110a Upper Surface

[0324] 110b Outer Peripheral Edge

[0325] 110d Lower Surface

[0326] 120, 320, 420 Water Retention Prevention Part

[0327] 120a, 420a Upper End Face

[0328] 120b, 320b Water Guide Inclined Surface

[0329] 120c Axle Approaching Surface

[0330] 130, 230 Enlarged Plane Part

[0331] 130a, 230a Upper End Face

[0332] 320a Upper End

[0333] 140 Peripheral Side Wall

[0334] 150 Embedded Recess

[0335] 151 Indicator Mark

[0336] 33 Retaining Ring

[0337] 33a Inner Peripheral Surface

[0338] 34 Lobe

[0339] 34a Hole

[0340] 41 Piston

[0341] 42 Piston Rod

[0342] 50 Anti-rotation yoke

[0343] 60 Rotary conversion mechanism

[0344] 600 Valve

[0345] 610 Valve body

[0346] 620 Valve stem (shaft)

[0347] 622 Prismatic part

[0348] M External mount

[0349] M1 Valve opening display board

[0350] AP1, AP2 Gas ports

[0351] P Pin

[0352] A1, A2, A3 Corners

[0353] G Gap

Claims

1. A valve actuator, comprising: An actuator body having an externally mounted member placement surface on its upper part where an externally mounted member can be freely mounted; A shaft, with one end at the lower part connected to the valve stem of the valve, and the upper end of the other end passing through a through hole formed in the externally mounted member placement surface and protruding from the inside to the outside of the actuator body; A shaft mounting member rotatably mounted above the externally mounted member placement surface together with the shaft; The valve actuator is characterized in that On the externally mounted member placement surface, when viewed from above, in the area that becomes the inside of the shaft mounting member, there is an annular convex portion integrally formed with the externally mounted member placement surface and protruding more than the surrounding area, such that the opening portion of the through hole is at a position higher than its periphery.

2. The valve actuator according to claim 1, Characterized in that The externally mounted member placement surface is a surface including a flange portion that expands in a flange shape at the upper part of the actuator body.

3. The valve actuator according to claim 1, Characterized in that The externally mounted member placement surface is a drainage surface that is lower than the annular convex portion in the area outside the annular convex portion.

4. The valve actuator according to claim 1, Characterized in that It has one or more shaft auxiliary parts for rotatably holding the shaft relative to the actuator body at a predetermined position, The shaft auxiliary parts are provided above the annular convex portion and below the shaft mounting member.

5. The valve actuator according to claim 4, Characterized in that The shaft auxiliary parts are arranged in the area that is the inside of the shaft mounting member when viewed from above.

6. The valve actuator according to any one of claims 1 to 5, Characterized in that The shaft mounting member is an indicator, the indicator has a shaft insertion through hole, the shaft insertion through hole has a shape corresponding to the cross-section of the shaft orthogonal to the shaft body, the upper end of the shaft passes through the shaft insertion through hole, and the indicator is mounted on the shaft, The indicator has a top wall formed with the shaft insertion through hole and a peripheral side wall hanging down along the outer peripheral surface of the top wall, The relative position relationship in the height direction between the lower end edge of the peripheral side wall and the opening portion of the through hole is set such that the lower end edge of the peripheral side wall is located at a position lower than the opening portion of the through hole.

7. The valve actuator according to claim 6, Characterized in that The shaft has a prism part and a cylindrical part below the prism part with a diameter of the cross-section larger than the distance between the opposite side surfaces of the prism part, The shaft insertion through hole of the indicator has a shape corresponding to the outer shape of the prism part, The indicator is such that the prism part is inserted through the shaft insertion through hole and the lower surface of the top wall seats on the boundary step part between the prism part and the cylindrical part and is thus mounted on the shaft.

8. The valve actuator according to claim 6, Characterized in that The lower end edge of the peripheral side wall of the indicator is set to a height lower than the opening portion of the through hole and away from the externally mounted member placement surface.

9. A shaft mounting member is mounted on a columnar portion of a shaft protruding from the upper part of a valve body or a valve actuator body. The columnar portion has at least one planar side surface on its circumferential side surface and a corner formed by the planar side surface and a side surface intersecting with the planar side surface. The upper surface of the shaft mounting member extends in the radially outer direction of the shaft. The shaft mounting member is characterized in that a water retention prevention portion is provided in a region of the upper surface close to the planar side surface of the columnar portion. The water retention prevention portion is configured with an upper end surface that suppresses the plane to be smaller or an inclined upper end surface, and a water guiding inclined surface is formed that inclines downward from the upper end surface or the upper end at a larger inclination angle than the region of the upper surface connected to the outer peripheral edge side in the radially outer direction.

10. The shaft mounting member according to claim 9, characterized in that an enlarged planar portion is provided. The enlarged planar portion forms an upper end surface composed of a plane whose width is enlarged in the radially outer direction compared with the upper end surface of the water retention prevention portion in a region of the upper surface close to the corner of the columnar portion of the shaft.

11. The shaft mounting member according to claim 10, characterized in that when the annular fixing member is abutted against the enlarged planar portion and fixed to the shaft, the width of the upper end surface of the water retention prevention portion in the radially outer direction is set to be smaller than the maximum width in the radially outer direction of the gap between the inner circumferential surface of the annular fixing member and the planar side surface of the columnar portion of the shaft.

12. A valve actuator, characterized in that the shaft mounting member according to any one of claims 9 to 11 is mounted on a columnar portion of a shaft that is connected to a valve stem of a valve and protrudes from the upper part of the actuator body. The columnar portion has at least one planar side surface that forms a straight portion as a part of the outer shape of a cross section orthogonal to the shaft body of the shaft and a corner formed by the planar side surface and a side surface intersecting with the planar side surface.

Images