Steam valve

Abstract

The present invention provides a steam valve that can suppress uneven contact between the valve stem and its surroundings, and that can be easily maintained. [Solution] A steam valve comprising a link mechanism for transmitting power from an actuator to a valve stem, and a guide mechanism for guiding the movement of the valve stem in the vertical direction, wherein the link mechanism includes a pair of levers, a connecting portion located between the pair of levers and integrally provided with the valve stem at the end of the valve stem opposite to the valve body, and a pin that pin-connects the pair of levers and the connecting portion, wherein the guide mechanism includes a guide rail, one of the pair of levers is located between the guide rail and the connecting portion, and the guide rail is configured to restrict the displacement of the pin in the horizontal direction intersecting the axial direction of the pin.

Description

Technical Field

[0001] The present disclosure relates to a steam valve.

Background Art

[0002] Patent Document 1 discloses a steam valve including a casing in which a valve seat is formed, a valve body that can abut against the valve seat, a valve rod connected to the valve body and extending along the vertical direction, an actuator, and a link mechanism for transmitting the power of the actuator to the valve rod. This link mechanism includes a pair of levers, a connecting portion provided integrally with the valve rod at an end of the valve rod on the side opposite to the valve body and located between the pair of levers, a pin for pin-connecting the pair of levers and the connecting portion, and a guide mechanism for restricting the horizontal displacement of the connecting portion. In such a steam valve, since the horizontal displacement of the connecting portion is restricted by the guide mechanism, it is possible to prevent one-sided contact between the valve rod and its periphery (a state where uniform contact cannot be obtained when the valve rod contacts the surrounding components and the valve rod contacts biased to one side).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the steam valve described in Patent Document 1, since the guide mechanism is located between the pair of levers in the axial direction of the pin, when performing maintenance of the guide mechanism, it takes effort to release the pin connection between the pair of levers and the connecting portion and disassemble the link mechanism, and it is not easy to perform maintenance of the guide mechanism.

[0005] In view of the above circumstances, at least one embodiment of the present disclosure aims to provide a steam valve that can suppress one-sided contact between the valve rod and its periphery and can be easily maintained. [Means for solving the problem]

[0006] To achieve the above objective, a steam valve according to at least one embodiment of this disclosure is: A casing in which a valve seat is formed, A valve body that can contact the valve seat, A valve stem connected to the valve body and extending in the vertical direction, Actuator and A link mechanism for transmitting power from the actuator to the valve stem, A guide mechanism for guiding the movement of the valve stem in the vertical direction, Equipped with, The aforementioned link mechanism is A pair of levers, A connecting portion is provided integrally with the valve stem at the end of the valve stem opposite to the valve body, located between the pair of levers, A pin that connects the pair of levers and the connecting portion, Includes, The guide mechanism includes a guide rail, One of the pair of levers is located between the guide rail and the connecting portion. The guide rail is configured to restrict the displacement of the pin in a horizontal direction intersecting the axial direction of the pin. [Effects of the Invention]

[0007] According to at least one embodiment of the present disclosure, a steam valve is provided that can suppress uneven contact between the valve stem and its surroundings, and that can be easily maintained. [Brief explanation of the drawing]

[0008] [Figure 1] This diagram shows a schematic configuration of a steam turbine system 2 to which a steam valve 1 according to one embodiment is applied. [Figure 2] Figure 1 is a partial cross-sectional view showing an example of the schematic configuration of the steam valve 1. [Figure 3]It is a schematic perspective view showing a part of the steam valve 1 shown in FIG. 2. [Figure 4] It is a schematic perspective view showing a part of a modified example of the steam valve 1. [Figure 5] It is a schematic perspective view showing an enlarged view of the vicinity of the connecting member 35 in the steam valve 1 shown in FIG. 4. [Figure 6] It is a view in the direction of arrow A in FIG. 5 (a view of the vicinity of the connecting member 35 along the axial direction of the pin 34). [Figure 7] It is an exploded perspective view showing a state in which the pin 34 and its peripheral configuration in FIGS. 4 to 6 are disassembled. [Figure 8] It is a schematic perspective view showing an enlarged view of the vicinity of the link 28 in the steam valve 1 shown in FIG. 4. [Figure 9] It is a view in the direction of arrow B in FIG. 8 (a view of the vicinity of the link 28 along the axial direction of the pin 27). [Figure 10] It is an exploded perspective view showing a state in which the pin 27 and its peripheral configuration in the steam valve 1 shown in FIGS. 4 and 8 are disassembled. [Figure 11] It is a schematic perspective view showing a modified example of the steam valve 1 shown in FIG. 3. [Figure 12] It is a view showing an example of the arrangement of the drive side guide 55, the bush 59, the solid lubricant 36, and the pin 34 in the axial direction view of the pin 34. [Figure 13] It is a view for explaining the contact of the drive side guide 55 with the solid lubricant 64 provided on the inner surface 45 of the slit 44.

Mode for Carrying Out the Invention

[0009] Hereinafter, some embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described as embodiments or shown in the drawings are not intended to limit the scope of the invention, but are merely illustrative examples. For example, expressions indicating relative or absolute arrangements such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric", or "coaxial" not only strictly represent such arrangements, but also represent states of relative displacement with tolerances, or angles and distances such that the same function can be obtained. For example, expressions indicating that things are in an equal state such as "identical", "equal", and "homogeneous" not only strictly represent an equal state, but also represent states where there are tolerances, or differences such that the same function can be obtained. For example, expressions indicating shapes such as a rectangular shape or a cylindrical shape not only represent shapes such as a rectangular shape or a cylindrical shape in a geometrically strict sense, but also represent shapes including concave and convex portions, chamfered portions, etc. within a range where the same effect can be obtained. On the other hand, expressions such as "comprising", "having", "including", or "possessing" one component are not exclusive expressions that exclude the existence of other components.

[0010] (Schematic Configuration of Steam Turbine System) FIG. 1 shows a schematic configuration of a steam turbine system 2 to which a steam valve 1 according to an embodiment is applied. The steam turbine system 2 includes a steam valve 1 and a steam turbine 4 to which steam (supply steam) is supplied from the steam valve 1. The steam turbine 4 can convert the energy of the supplied steam into power and output it, and the steam (exhaust steam) from which the energy has been extracted is discharged from the steam turbine 4. For example, the power output by the steam turbine 4 is transmitted to a generator 6, and the generator 6 generates electricity using the power.

[0011] (Example of Schematic Configuration of Steam Valve) FIG. 2 is a partial cross-sectional view showing an example of the schematic configuration of the steam valve 1 shown in FIG. 1. FIG. 3 is a schematic perspective view showing a part of the steam valve 1 shown in FIG. 2. For example, as shown in Figure 2, the steam valve 1 comprises a casing 9 on which a valve seat 8 is formed, a valve body 10 that can contact the valve seat 8, a valve stem 12 connected to the valve body 10 and extending in the vertical direction, an actuator 14, a link mechanism 16 for transmitting power from the actuator 14 to the valve stem 12, and a first guide mechanism 18 for guiding the movement of the valve stem 12 in the vertical direction.

[0012] The casing 9 includes an inlet passage 20 through which steam is introduced, a valve chamber 21 through which the steam introduced from the inlet passage 20 passes, and an outlet passage 22 for discharging steam from the valve chamber 21. An annular valve seat 8 is formed around the opening in the valve chamber 21 to which the outlet passage 22 connects. The upper end (one end of the valve stem 12) of the valve stem 12 is connected to the valve body 10 inside the casing 9, and the valve stem 12 extends vertically downward from the valve body 10. The lower end (the other end of the valve stem 12) is located outside the casing 9 and is connected to a link mechanism 16 below the casing 9. The type of actuator 14 is not particularly limited, but the actuator 14 may be composed of, for example, a hydraulic cylinder.

[0013] In the exemplary embodiments shown in Figures 2 and 3, the link mechanism 16 comprises a rod 24, a knuckle 26, a pin 27, a link 28, a pin 29, a pair of levers 30, a pin 31, a link 32, a pin 33, a pin 34, and a connecting member 35 (connecting part).

[0014] The upper end of the rod 24 (one end of the rod 24) is connected to the actuator 14, and the rod 24 extends vertically downward from the actuator 14. The lower end of the rod 24 (the other end of the rod 24) is connected to the knuckle 26, and the rod 24 and the knuckle 26 move vertically together by the power of the actuator 14.

[0015] The lower end of the knuckle 26 and the upper end of the link 28 are pin-connected by a pin 27, and the link 28 is rotatable around the axis of the pin 27. The lower end of the link 28 and one end 30a of each of the pair of levers 30 are pin-connected by a pin 29, and the link 28 and the pair of levers 30 are rotatable around the axis of the pin 29.

[0016] The central portion of each of the pair of levers 30 and the lower end of the link 32 are pin-connected by a pin 31, and each of the pair of levers 30 and the link 32 are rotatable around the axis of the pin 31. The upper end of the link 32 and the casing 9 are pin-connected by a pin 33, and the link 32 is rotatable around the axis of the pin 33. The other end 30b of each of the pair of levers 30 and the lower end of the connecting member 35 are pin-connected by a pin 34, and each of the pair of levers 30 is rotatable around the axis of the pin 34.

[0017] The connecting member 35 is fixed to the lower end of the valve stem 12 (the end of the valve stem 12 opposite to the valve body 10) and is integrally provided with the valve stem 12. The valve stem 12 and the connecting member 35 move vertically together as a single unit. The connecting member 35 is located between a pair of levers 30 (more specifically, between the other ends 30b of each of the pair of levers 30). The dimensions of the connecting member 35 in the radial direction of the valve stem 12 are larger than the diameter of the valve stem 12, and the lower end of the valve stem 12 is fixed to the upper end of the connecting member 35.

[0018] As shown in Figure 3, the first guide mechanism 18 includes a pair of guide rails 40 fixed to the casing 9. The pair of levers 30 and the connecting member 35 are located between the pair of guide rails 40. More specifically, the other end 30b of each of the pair of levers 30 and the lower end of the connecting member 35 are located between the pair of guide rails 40 in the axial direction of the pin 34. Also, one of the pair of levers 30 is located between one of the pair of guide rails 40 and the connecting member 35, and the other of the pair of levers 30 is located between the other of the pair of guide rails 40 and the connecting member 35. The pair of guide rails 40 are configured to restrict the displacement of the pin 34 in the horizontal direction H intersecting the axial direction of the pin 34 (more specifically, the horizontal direction perpendicular to the axial direction of the pin 34). Note that the configuration of the first guide mechanism 18 is symmetrical with respect to a vertical plane passing between the pair of levers 30 (a vertical plane that includes the axis of the valve stem 12 and is perpendicular to the axis of the pin 34), so in the following description, the same reference numerals may be used to describe the configurations on both sides of this vertical plane.

[0019] Each of the pair of guide rails 40 extends vertically, and the upper part of each of the pair of guide rails 40 is connected to the casing 9. In the illustrated exemplary embodiment, the first guide mechanism 18 includes a reinforcing plate 42 that connects the lower parts of each of the pair of guide rails 40. The reinforcing plate 42 is located below the connecting member 35 (below the pair of levers 30) and extends along the axial direction of the pin 34 from the lower part of one of the pair of guide rails 40 to the lower part of the other guide rail 40.

[0020] In the illustrated exemplary embodiment, each of the pair of guide rails 40 includes a first plate portion 40a, a second plate portion 40b, and a third plate portion 40c. The first plate portion 40a is connected to the casing 9 and extends vertically. The second plate portion 40b connects the first plate portion 40a and the third plate portion 40c and is inclined to approach the connecting member 35 as it moves from the first plate portion 40a side towards the third plate portion 40c side. The third plate portion 40c extends vertically from the lower end of the second plate portion 40b to one end of the reinforcing plate 42 in the axial direction of the pin 34.

[0021] Each of the pair of guide rails 40 includes a guide slit 44 for guiding the pin 34 vertically. In the illustrated exemplary embodiment, the guide slit 44 is a through hole that penetrates the guide rail 40 in the axial direction of the pin 34, and penetrates the third plate portion 40c of the guide rail 40 in the axial direction of the pin 34. The longitudinal direction of the guide slit 44 is vertical, and the slit length of the guide slit 44 in the vertical direction is greater than the dimensions of the guide slit 44 in the axial direction of the pin 34 (i.e., the thickness of the third plate portion 40c), and greater than the slit width of the guide slit 44 in the horizontal direction H perpendicular to the axial direction of the pin 34.

[0022] One end 34a of the pin 34 is located inside the guide slit 44 of one of the pair of guide rails 40, and the other end 34b of the pin 34 is located inside the guide slit 44 of the other of the pair of guide rails 40. The pin 34 may be a single integrally molded part, or it may be composed of multiple pin members connected in the axial direction.

[0023] The inner surfaces 45 of each guide slit 44 of the pair of guide rails 40 include an upper surface 45a and a lower surface 45b and a pair of opposing sides 45c and 45d. One end 34a of the pin 34 moves vertically along the pair of sides 45c and 45d of the guide slit 44 of one of the pair of guide rails 40, and the other end 34b of the pin 34 moves vertically along the pair of sides 45c and 45d of the guide slit 44 of the other of the pair of guide rails 40. Each of the pair of sides 45c and 45d may be a plane perpendicular to the horizontal direction H.

[0024] In the embodiments shown in Figures 2 and 3, power from the actuator 14 is transmitted to the valve stem 12 via the link mechanism 16, causing the valve stem 12 to move vertically. For example, when the rod 24 and knuckle 26 move downward due to the power from the actuator 14, one end 30a of each of the pair of levers 30, which are pin-connected to the link 28, is pushed downward via the link 28, which is pin-connected to the knuckle 26. As a result, the pair of levers 30 rotate around the axis of the pin 31, causing the other end 30b of each of the pair of levers 30 to move upward, and the valve stem 12 moves upward via the connecting member 35, which is pin-connected to the other end 30b of the pair of levers 30. Alternatively, when the rod 24 and knuckle 26 move upward due to the power from the actuator 14, one end 30a of each of the pair of levers 30, which are pin-connected to the link 28, is pulled upward via the link 28, which is pin-connected to the knuckle 26. As a result, the pair of levers 30 rotate around the axis of the pin 31, causing the other end 30b of each lever 30 to move downward, and the valve stem 12 moves downward via the connecting member 35 which is pin-connected to the other end 30b of the pair of levers 30.

[0025] Furthermore, since the pair of guide rails 40 restrict the displacement of the pin 34 in the horizontal direction intersecting the axial direction of the pin 34, uneven contact between the valve stem 12 and its surroundings (casing 9, etc.) can be suppressed. Also, since the pair of levers 30 and the connecting member 35 are positioned between the pair of guide rails 40, compared to the configuration described in Patent Document 1 (a configuration in which the guide mechanism is positioned between the pair of levers in the axial direction of the pin that pin-connects the pair of levers and the connecting member), maintenance of the first guide mechanism 18 is easier because it does not require the effort of releasing the pin connection between the pair of levers 30 and the connecting member 35 and disassembling the link mechanism 16.

[0026] (A variation of a steam valve) Figure 4 is a schematic perspective view showing a modified example of the steam valve 1. Figure 5 is a schematic perspective view showing a magnified view of the vicinity of the connecting member 35 in the steam valve 1 shown in Figure 4. Figure 6 is a view in direction A of Figure 5 (view of the vicinity of the connecting member 35 along the axial direction of the pin 34). Figure 7 is an exploded perspective view showing the pin 34 and its surrounding components as shown in Figures 4 to 6.

[0027] Since the basic configuration of the steam valve 1 in the embodiment shown in Figure 4 is the same as the configuration of the steam valve 1 described using Figures 2 and 3, the differences between the steam valve 1 in the embodiment shown in Figure 4 and the steam valve 1 in the embodiment described using Figures 2 and 3 will be explained below.

[0028] In some embodiments, as shown in at least one of Figures 5 and 7, for example, the pin 34 that pin-connects the pair of levers 30 and the connecting member 35 may consist of a first pin member 50 that penetrates the pair of levers 30 and the connecting member 35, a second pin member 52 connected to one end of the first pin member 50, and a third pin member 54 connected to the other end of the first pin member 50. For the purposes of the following explanation, one of the pair of levers 30 (the lever 30 on the side of one end 34a of the pin 34, i.e., the lever 30 on the side of the second pin member 52) may be referred to as lever 301, the other of the pair of levers (the lever 30 on the side of the other end 34b of the pin 34, i.e., the lever 30 on the side of the third pin member 54) may be referred to as lever 302, one of the pair of guide rails 40 (the guide rail 40 on the side of one end 34a of the pin 34, i.e., the guide rail 40 on the side of the second pin member 52) may be referred to as guide rail 401, and the other of the pair of guide rails 40 (the guide rail 40 on the side of the other end 34b of the pin 34, i.e., the guide rail 40 on the side of the third pin member 54) may be referred to as guide rail 402. In the illustrated exemplary form, lever 301 is located between guide rail 401 and connecting member 35, and lever 302 is located between guide rail 402 and connecting member 35.

[0029] The first pin member 50 connects the pair of levers 30 and the connecting member 35 with a pin. Both ends of the first pin member 50 protrude from the pair of levers 30 toward the opposite side of the connecting member 35. That is, one end of the first pin member 50 protrudes from the lever 301 toward the opposite side of the connecting member 35, and the other end of the first pin member 50 protrudes from the lever 302 toward the opposite side of the connecting member 35. Washers 51 are attached to the outer circumferential surface of each end of the first pin member 50, and the axial positioning of the first pin member 50 may be achieved by engaging retaining pins (not shown), which are fixed to both ends of the first pin member 50, with the washers 51.

[0030] The second pin member 52 is fixed coaxially to one end of the first pin member 50 with a plurality of bolts 53, and the third pin member 54 is fixed coaxially to the other end of the first pin member 50 with a plurality of bolts 53. The second pin member 52 includes a portion located inside the guide slit 44 of the guide rail 401, and the third pin member 54 includes a portion located inside the guide slit 44 of the guide rail 402.

[0031] In some embodiments, as shown in Figures 4 to 7, for example, the first guide mechanism 18 includes a pair of drive-side guides 55. In the embodiments shown in Figures 4 to 7, the configuration of the first guide mechanism 18 is symmetrical with respect to a vertical plane passing between the pair of levers 30 (a vertical plane that includes the axis of the valve stem 12 and is perpendicular to the axis of the pin 34). Therefore, in the following description, the same reference numerals may be used to describe the configurations on both sides of this vertical plane in the first guide mechanism 18.

[0032] For example, as shown in Figure 5, one of the pair of drive-side guides 55 is attached to the outer circumferential surface of the pin 34 (the outer circumferential surface of the second pin member 52) at one end 34a of the pin 34, and is located inside the guide slit 44 of the guide rail 401. The other of the pair of drive-side guides 55 is attached to the outer circumferential surface of the pin 34 (the outer circumferential surface of the third pin member 54) at the other end 34b of the pin 34, and is located inside the guide slit 44 of the guide rail 402. For convenience of explanation, in the following description, one of the pair of drive-side guides 55 (the drive-side guide 55 on the end 34a of the pin 34, i.e., the drive-side guide 55 on the second pin member 52 side) may be referred to as drive-side guide 551, and the other of the pair of drive-side guides 55 (the drive-side guide 55 on the other end 34b of the pin 34, i.e., the drive-side guide 55 on the third pin member 54 side) may be referred to as drive-side guide 552.

[0033] For example, as partially shown in Figure 6, each outer surface 56 of a pair of drive-side guides 55 includes a pair of planes 62, 63 facing the inner surface 45 of the guide slit 44 of the corresponding guide rail 40. The outer surface 56 of drive-side guide 551 includes a pair of planes 62, 63 facing the inner surface 45 of the guide slit 44 of the guide rail 401, and the outer surface 56 of drive-side guide 552 includes a pair of planes 62, 63 facing the inner surface 45 of the guide slit 44 of the guide rail 402. The pair of planes 62, 63 face opposite directions in the horizontal direction. Each of the pair of planes 62, 63 is a plane perpendicular to the horizontal direction H (a plane perpendicular to the axis of the valve stem 12 and the axis of the pin 34, respectively), with plane 62 facing the side surface 45c of the guide slit 44 and plane 63 facing the side surface 45d of the guide slit 44.

[0034] For example, as partially shown in Figure 7, each of the pair of drive-side guides 55 has a through-hole 58 through which a pin 34 passes, and the first guide mechanism 18 further includes cylindrical bushings 59 fitted into each of the through-holes 58 of the pair of drive-side guides 55. The bushings 59 are inserted into and fixed in the through-holes 58 and rotatably support the pin 34. A second pin member 52 is inserted through the bushing 59 fixed in the through-hole 58 of the drive-side guide 551, and a third pin member 54 is inserted through the bushing 59 fixed in the through-hole 58 of the drive-side guide 552.

[0035] For example, as partially shown in Figure 7, with respect to bushes 59 fitted into each through hole 58 of a pair of drive-side guides 55, a solid lubricant 36 may be provided on the inner circumferential surface 59a of the bush 59 or on the surface 34s of the pin 34 facing the inner circumferential surface 59a of the bush 59 (in the illustrated example, the inner circumferential surface 59a of the bush 59). This solid lubricant 36 may be fixed to the inner circumferential surface 59a of the bush 59 or on the surface 34s of the pin 34 facing the inner circumferential surface 59a of the bush 59 (the portion of the outer circumferential surface of the pin 34 facing the inner circumferential surface 59a of the bush 59). Furthermore, this solid lubricant 36 may be formed in a cylindrical shape (layered) along the inner circumferential surface 59a of the bush 59 or on the surface 34s of the pin 34 facing the inner circumferential surface 59a of the bush 59, as shown in Figure 12, for example, or the entire bush 59 may be formed of solid lubricant.

[0036] The material of the solid lubricant 36 may be, for example, a soft metal, metal oxide, sulfide, fluoride, nitride, elemental graphite, or an organic compound, or it may be any other material that can be used as a solid lubricant. Furthermore, the coefficient of friction between the solid lubricant 36 and the member facing the bush 59 in the radial direction (the pin 34 when the solid lubricant 36 is fixed to the inner circumferential surface 59a of the bush 59, the bush 59 when the solid lubricant 36 is fixed to the surface 34s of the pin 34, or the pin 34 when the entire bush 59 is formed of solid lubricant) may be, for example, 0.25 or less, and more preferably 0.2 or less.

[0037] A washer 60 may be provided on the outer circumferential surface of the second pin member 52 at a position between the drive-side guide 551 and the multiple bolts 53, and a washer 60 may be provided on the outer circumferential surface of the third pin member 54 at a position between the drive-side guide 552 and the multiple bolts 53. Alternatively, a washer 61 may be attached to the outer circumferential surface of the second pin member 52 at a position opposite to the first pin member 50 relative to the drive-side guide 551, and a retaining pin (not shown) fixed to the end of the second pin member 52 opposite to the first pin member 50 may engage with the washer 61, thereby causing the washer 61 to function as a retainer for the drive-side guide 551. Furthermore, a washer 61 may be attached to the outer circumferential surface of the third pin member 54 at a position opposite to the first pin member 50 relative to the drive-side guide 552, and a retaining pin (not shown) fixed to the end of the third pin member 54 opposite to the first pin member 50 may engage with the washer 61, thereby causing the washer 61 to function as a retainer for the drive-side guide 552.

[0038] For example, as partially shown in Figures 5 and 6, the first guide mechanism 18 may include plate-shaped solid lubricants 64 provided on the inner surface 45 of the guide slits 44 in each of the pair of guide rails 40. In the illustrated exemplary embodiment, the first guide mechanism 18 includes solid lubricants 64 fixed to the side surface 45c of the guide slit 44 of the guide rail 401, solid lubricants 64 fixed to the side surface 45d of the guide slit 44 of the guide rail 401, solid lubricants 64 fixed to the side surface 45c of the guide slit 44 of the guide rail 402, and solid lubricants 64 fixed to the side surface 45d of the guide slit 44 of the guide rail 402. The material of each solid lubricant 64 in the first guide mechanism 18 may be, for example, a soft metal, a metal oxide, a sulfide, a fluoride, a nitride, elemental graphite, or an organic compound, or any other material that can be used as a solid lubricant. Furthermore, the coefficient of friction between each solid lubricant 64 of the first guide mechanism 18 and the drive-side guide 55 (drive-side guide 551 or drive-side guide 552) may be, for example, 0.25 or less, and more preferably 0.2 or less.

[0039] The drive-side guide 551 is sandwiched between a solid lubricant 64 fixed to the side surface 45c of the guide slit 44 of the guide rail 401 and a solid lubricant 64 fixed to the side surface 45d of the guide slit 44 of the guide rail 401, and is configured to slide relative to these solid lubricants 64. The plane 62 of the drive-side guide 55 is in contact with the solid lubricant 64 fixed to the side surface 45c of the guide slit 44 of the guide rail 401, and the plane 63 of the drive-side guide 551 is in contact with the solid lubricant 64 fixed to the side surface 45d of the guide slit 44 of the guide rail 401. The drive-side guide 552 is sandwiched between a solid lubricant 64 fixed to the side surface 45c of the guide slit 44 of the guide rail 402 and a solid lubricant 64 fixed to the side surface 45d of the guide slit 44 of the guide rail 402, and is configured to slide relative to these solid lubricants 64. The plane 62 of the drive-side guide 552 is in contact with a solid lubricant 64 fixed to the side surface 45c of the guide slit 44 of the guide rail 402, and the plane 63 of the drive-side guide 552 is in contact with a solid lubricant 64 fixed to the side surface 45d of the guide slit 44 of the guide rail 402. A shim (not shown) may be interposed between each solid lubricant 564 and the inner surface of the guide slit 44 for dimensional adjustment.

[0040] For example, as shown in Figures 4 to 6, the first guide mechanism 18 includes a plurality of bolts 66 for fastening a pair of guide rails 40 to the casing 9. In the illustrated exemplary embodiment, the first guide mechanism 18 includes a plurality of bolts 66 for fastening the upper part of guide rail 401 to the casing 9 and a plurality of bolts 66 for fastening the upper part of guide rail 402 to the casing 9. For example, as partially shown in Figure 6, a horizontal slit 68 may be formed at the upper part of each of the pair of guide rails 40, extending along the horizontal direction H and through which the shafts of the bolts 66 are inserted. In this case, the pair of guide rails 40 are configured to slide horizontally in the horizontal direction H relative to the casing 9.

[0041] In some embodiments, as shown in Figures 5 and 6, for example, the guide rail 40 may include a component 40A that constitutes a guide slit 44 and a component 40B that is a separate component from component 40A and constitutes a horizontal slit 68. Component 40A and component 40B may be integrally molded separately.

[0042] Here, we will explain the effects of the first guide mechanism 18 in the steam valve 1 according to the embodiment shown in Figures 4 to 7. In the embodiments shown in Figures 4 to 7, the pair of guide rails 40 restrict the displacement of the pin 34 in the horizontal direction intersecting the axial direction of the pin 34, thereby suppressing uneven contact between the valve stem 12 and its surroundings (casing 9, etc.). Furthermore, since the pair of levers 30 and the connecting member 35 are positioned between the pair of guide rails 40, compared to the configuration described in Patent Document 1 (a configuration in which the guide mechanism is positioned between the pair of levers in the axial direction of the pin that pin-connects the pair of levers and the connecting member), maintenance of the first guide mechanism 18 is easier because it does not require the effort of releasing the pin connection between the pair of levers 30 and the connecting member 35 and disassembling the link mechanism 16.

[0043] Furthermore, the solid lubricant 64 allows the pin 34 to move smoothly in the vertical direction, enabling smooth opening and closing of the valve in the steam valve 1. In addition, wear on the pin 34's components can be suppressed when the pin 34 moves vertically within the guide slit 44. Moreover, even if the solid lubricant 64 wears out, replacing the solid lubricant 64 can suppress uneven contact between the valve stem 12 and its surroundings while maintaining the smooth opening and closing operation of the valve, thereby improving the maintainability of the first guide mechanism 18.

[0044] Furthermore, since the first guide mechanism 18 is equipped with a pair of drive-side guides 55, the contact area between the pin 34 side configuration and the guide rail 40 side configuration can be increased compared to the case where the outer circumferential surface of the pin 34 slides against the configuration on the guide rail 40 side (for example, the configuration shown in Figure 3, etc.). As a result, when the pin 34 side configuration slides against the configuration on the guide rail 40 side, it is possible to suppress the localized large force acting on the sliding part, and thus prevent damage to the first guide mechanism 18.

[0045] Furthermore, since the outer surface 56 of the drive-side guide 551 includes a pair of planes 62, 63 facing the inner surface 45 of the guide slit 44 of the guide rail 401, and the outer surface 56 of the drive-side guide 552 includes a pair of planes 62, 63 facing the inner surface 45 of the guide slit 44 of the guide rail 402, the effect of increasing the contact area between the pin 34 side configuration and the guide rail 40 side configuration can be enhanced. As a result, when the pin 34 side configuration slides against the guide rail 40 side configuration, it is possible to suppress the localized large force acting on the sliding part, and damage to the first guide mechanism 18 can be effectively suppressed.

[0046] Furthermore, since the first guide mechanism 18 is equipped with bushings 59 fitted into the through holes 58 of each of the pair of drive-side guides 55, even if the bushings 59 wear out, only the bushings 59 can be replaced, improving the maintainability of the first guide mechanism 18. In addition, by using a material with a low coefficient of friction for the bushings 59, wear of the pins 34 can be suppressed.

[0047] Furthermore, since the second pin member 52 and the third pin member 54 are configured as separate parts from the first pin member 50 that penetrates the pair of levers 30 and the connecting member 35, the second pin member 52 and the third pin member 54 can be replaced while maintaining the state in which the pair of levers 30 and the connecting member 35 are connected by the first pin member 50 (without disassembling the pair of levers 30, the connecting member 35 and the first pin member 50). This improves the maintainability of the first guide mechanism 18. In addition, the steam valve 1 can also be realized by retrofitting the second pin member 52, the third pin member 54 and the first guide mechanism 18 to an existing steam valve equipped with the first pin member 50.

[0048] Furthermore, as explained using Figures 7 and 12, the coefficient of friction between the bush 59 and the pin 34 (more specifically, the coefficient of friction between the solid lubricant 36 provided on the inner circumferential surface 59a of the bush 59 and the surface 34s of the pin 34, the coefficient of friction between the solid lubricant 36 provided on the surface 34s of the pin 34 facing the inner circumferential surface 59a of the bush 59 and the inner circumferential surface 59a of the bush 59, or the coefficient of friction between the inner circumferential surface 59a of the bush 59 and the surface 34s of the pin 34) can be reduced. As a result, even if the direction of the force transmitted from the pair of levers 30 to the pair of drive-side guides 55 via the pin 34 is in an oblique direction that intersects the vertical and horizontal directions, the rotation of the pair of drive-side guides 55 around the axis of the pin 34 can be suppressed. As a result, uneven contact between the drive-side guide 55 and the inner surface of the guide slit 44 or the solid lubricant 64 formed on the inner surface of the guide slit 44 can be suppressed (see Figure 13).

[0049] Figure 8 is a schematic perspective view showing an enlarged view of the vicinity of link 28 in the steam valve 1 shown in Figure 4. Figure 9 is a view in direction B of Figure 8 (a view of the vicinity of link 28 along the axis of pin 27). Figure 10 is an exploded perspective view showing the pin 27 and its surrounding components in the steam valve 1 shown in Figures 4 and 8 in an disassembled state.

[0050] As shown in Figure 8, the knuckle 26 includes a base 47 connected to the rod and a pair of arm portions 48 that branch out from the base 47 and extend downward. The upper end of the link 28 (one end of the link 28) is located between the pair of arm portions 48. The pin 27 passes through the pair of arm portions 48 and the upper end of the link 28, pin-connecting the pair of arm portions 48 and the upper end of the link 28. For convenience of explanation, in the following description, one of the pair of arm portions 48 (the end 27a of the pin 27) may be referred to as arm portion 481, and the other of the pair of arm portions 48 (the other end 27b of the pin 27) may be referred to as arm portion 482.

[0051] In some embodiments, as shown in Figure 8, for example, the steam valve 1 includes a second guide mechanism 19 that guides the movement of the knuckle 26 in the vertical direction. The second guide mechanism 19 includes a pair of guide rails 70 fixed to the casing 9. The pair of arm portions 48 and the link 28 are located between the pair of guide rails 70. More specifically, the upper ends of the pair of arm portions 48 and the link 28 are located between the pair of guide rails 70 in the axial direction of the pin 27. The pair of guide rails 70 are configured to restrict the displacement of the pin 27 in the horizontal direction H intersecting the axial direction of the pin 27 (more specifically, the horizontal direction perpendicular to the axial direction of the pin 27). Since the configuration of the second guide mechanism 19 is symmetrical with respect to a vertical plane passing between the pair of arm portions 48 (a vertical plane in Figure 2 that includes the axis of the rod 24 and is perpendicular to the axis of the pin 27), the same reference numerals may be used to describe the configurations on both sides of the vertical plane in the second guide mechanism 19 in the following description. In addition, one of the pair of guide rails 70 (the end 27a side of the pin 27) may be described as guide rail 701, and the other of the pair of guide rails 70 (the other end 27b side of the pin 27) may be described as guide rail 702. In the illustrated exemplary form, arm portion 481 is located between guide rail 701 and link 28, and arm portion 482 is located between guide rail 702 and link 28.

[0052] Each of the pair of guide rails 70 extends vertically, and the upper part of each of the pair of guide rails 70 is connected to the casing 9. Each of the pair of guide rails 70 includes a guide slit 74 for guiding the pin 27 vertically. In the illustrated exemplary embodiment, the guide slit 74 is a through hole that penetrates the guide rail 70 in the axial direction of the pin 27. The longitudinal direction of the guide slit 74 is vertical, and the slit length of the guide slit 74 in the vertical direction is greater than the dimension of the guide slit 74 in the axial direction of the pin 27, and greater than the slit width of the guide slit 74 in the horizontal direction H perpendicular to the axial direction of the pin 27.

[0053] One end 27a of the pin 27 is located inside the guide slit 74 of the guide rail 701, and the other end 27b of the pin 27 is located inside the guide slit 74 of the guide rail 702.

[0054] The inner surfaces 75 of each guide slit 74 of the pair of guide rails 70 include an upper surface 75a and a lower surface 75b and a pair of opposing sides 75c and 75d. One end 27a of the pin 27 moves vertically along the pair of sides 75c and 47d of the guide slit 74 of the guide rail 701, and the other end 27b of the pin 27 moves vertically along the pair of sides 75c and 75d of the guide slit 74 of the guide rail 702. Each of the pair of sides 75c and 75d may be a plane perpendicular to the horizontal direction H.

[0055] In some embodiments, as shown in at least one of Figures 8 and 10, for example, the pin 27 connecting the knuckle 26 and the link 28 may consist of a first pin member 80 that penetrates the knuckle 26 and the link 28, a second pin member 82 connected to one end of the first pin member 80, and a third pin member 84 connected to the other end of the first pin member 80. However, in other embodiments, the pin 27 may be a single, integrally molded part.

[0056] The first pin member 80 connects the pair of arm portions 48 and the link 28 with a pin. Both ends of the first pin member 80 protrude from the pair of arm portions 48 toward the opposite side of the link 28. That is, one end of the first pin member 80 protrudes from the arm portion 481 toward the opposite side of the link 28, and the other end of the first pin member 80 protrudes from the arm portion 482 toward the opposite side of the link 28.

[0057] The second pin member 82 is fixed coaxially to one end of the first pin member 80 with a plurality of bolts 83, and the third pin member 84 is fixed coaxially to the other end of the first pin member 80 with a plurality of bolts 83. The second pin member 82 includes a portion located inside the guide slit 74 of the guide rail 701, and the third pin member 84 includes a portion located inside the guide slit 74 of the guide rail 702. In the illustrated example, the end of the second pin member opposite to the first pin member 80 is located inside the guide slit 74 of the guide rail 701, and the end of the third pin member 84 opposite to the first pin member 80 is located inside the guide slit 74 of the guide rail 702.

[0058] In some embodiments, as shown in Figures 4 and 8 to 10, for example, the second guide mechanism 19 includes a pair of drive-side guides 85. For example, as shown in Figure 8, one of the pair of drive-side guides 85 is mounted on the outer circumferential surface of the pin 27 (the outer circumferential surface of the second pin member 82) at one end 27a of the pin 27, and is located inside the guide slit 74 of the guide rail 701. The other of the pair of drive-side guides 85 is mounted on the outer circumferential surface of the pin 27 (the outer circumferential surface of the third pin member 84) at the other end 27b of the pin 27, and is located inside the guide slit 74 of the guide rail 702. For convenience of explanation, in the following description, one of the pair of drive-side guides 85 (the drive-side guide 85 on the side of one end 34a of the pin 27, i.e., the drive-side guide 85 on the side of the second pin member 82) may be referred to as drive-side guide 851, and the other of the pair of drive-side guides 85 (the drive-side guide 85 on the side of the other end 27b of the pin 27, i.e., the drive-side guide 85 on the side of the third pin member 84) may be referred to as drive-side guide 852.

[0059] For example, as partially shown in Figure 9, each outer surface 86 of a pair of drive-side guides 85 includes a pair of planes 92, 93 facing the inner surface 75 of the guide slit 74 of the corresponding guide rail 70. The outer surface 86 of drive-side guide 851 includes a pair of planes 92, 93 facing the inner surface 75 of the guide slit 74 of the guide rail 701, and the outer surface 86 of drive-side guide 852 includes a pair of planes 92, 93 facing the inner surface 75 of the guide slit 74 of the guide rail 702. The pair of planes 92, 93 face opposite directions in the horizontal direction. Each of the pair of planes 92, 93 is a plane perpendicular to the horizontal direction H (a plane perpendicular to the axis of the rod 24 and the axis of the pin 27, respectively), with plane 92 facing the side surface 75c of the guide slit 74 and plane 93 facing the side surface 75d of the guide slit 74.

[0060] For example, as partially shown in Figure 10, each of the pair of drive-side guides 85 has a through-hole 88 through which a pin 27 passes, and the first guide mechanism 18 further includes cylindrical bushings 89 fitted into each of the through-holes 88 of the pair of drive-side guides 85. The bushings 89 are inserted into and fixed in the through-holes 88 and rotatably support the pin 27. A second pin member 82 is inserted through the bushing 89 fixed in the through-hole 88 of the drive-side guide 851, and a third pin member 84 is inserted through the bushing 89 fixed in the through-hole 88 of the drive-side guide 852.

[0061] For example, as partially shown in Figure 10, with respect to bushes 89 fitted into each through hole 88 of a pair of drive-side guides 85, a solid lubricant 38 may be provided on the inner circumferential surface 89a of the bush 89 or on the surface 27s of the pin 27 facing the inner circumferential surface 89a of the bush 89 (in the illustrated example, the inner circumferential surface 89a of the bush 89). This solid lubricant 38 may be fixed to the inner circumferential surface 89a of the bush 89 or on the surface 27s of the pin 27 facing the inner circumferential surface 89a of the bush 89 (the portion of the outer circumferential surface of the pin 27 facing the inner circumferential surface 89a of the bush 89). Furthermore, this solid lubricant 38 may be formed in a cylindrical shape (layered) along the inner circumferential surface 89a of the bush 89 or on the surface 27s of the pin 27 facing the inner circumferential surface 89a of the bush 89, similar to the configuration shown in Figure 12, or the entire bush 89 may be formed of solid lubricant.

[0062] The material of the solid lubricant 38 may be, for example, a soft metal, metal oxide, sulfide, fluoride, nitride, elemental graphite, or an organic compound, or it may be any other material that can be used as a solid lubricant. Furthermore, the coefficient of friction between the solid lubricant 38 and the member facing the bush 89 in the radial direction (the pin 27 when the solid lubricant 38 is fixed to the inner circumferential surface 89a of the bush 89, the bush 89 when the solid lubricant 38 is fixed to the surface 27s of the pin 27, or the pin 27 when the entire bush 89 is formed of solid lubricant) and each solid lubricant 38 may be, for example, 0.25 or less, and more preferably 0.2 or less.

[0063] A washer 90 may be provided on the outer circumferential surface of the second pin member 82 at a position between the drive-side guide 851 and the multiple bolts 83, and a washer 90 may be provided on the outer circumferential surface of the third pin member 84 at a position between the drive-side guide 852 and the multiple bolts 83. Alternatively, a washer 91 may be attached to the outer circumferential surface of the second pin member 82 at a position opposite to the first pin member 80 relative to the drive-side guide 851, and a retaining pin (not shown) fixed to the end of the second pin member 82 opposite to the first pin member 80 may engage with the washer 91, thereby causing the washer 91 to function as a retainer for the drive-side guide 851. Furthermore, a washer 91 may be attached to the outer circumferential surface of the third pin member 84 at a position opposite to the first pin member 80 relative to the drive-side guide 852, and a retaining pin (not shown) fixed to the end of the third pin member 84 opposite to the first pin member 80 may engage with the washer 91, thereby causing the washer 91 to function as a retainer for the drive-side guide 852.

[0064] For example, as partially shown in Figures 8 and 9, the second guide mechanism 19 may include plate-shaped solid lubricants 94 provided on the inner surface 75 of the guide slits 74 in each of the pair of guide rails 70. In the illustrated exemplary embodiment, the second guide mechanism 19 includes solid lubricants 94 fixed to the side surface 75c of the guide slit 74 of the guide rail 701, solid lubricants 94 fixed to the side surface 75d of the guide slit 74 of the guide rail 701, solid lubricants 94 fixed to the side surface 75c of the guide slit 74 of the guide rail 702, and solid lubricants 94 fixed to the side surface 75d of the guide slit 74 of the guide rail 702.

[0065] The material of each solid lubricant 94 in the second guide mechanism 19 may be, for example, a soft metal, metal oxide, sulfide, fluoride, nitride, elemental graphite, or an organic compound, or it may be any other material that can be used as a solid lubricant. Furthermore, the coefficient of friction between each solid lubricant 94 in the second guide mechanism 19 and the drive-side guide 85 (drive-side guide 851 or drive-side guide 852) may be, for example, 0.25 or less, and more preferably 0.2 or less.

[0066] The drive-side guide 851 is sandwiched between a solid lubricant 94 fixed to the side surface 75c of the guide slit 74 of the guide rail 701 and a solid lubricant 94 fixed to the side surface 75d of the guide slit 74 of the guide rail 701, and is configured to slide relative to these solid lubricants 94. The plane 92 of the drive-side guide 85 is in contact with the solid lubricant 94 fixed to the side surface 75c of the guide slit 74 of the guide rail 701, and the plane 93 of the drive-side guide 851 is in contact with the solid lubricant 94 fixed to the side surface 75d of the guide slit 74 of the guide rail 701. The drive-side guide 852 is sandwiched between a solid lubricant 94 fixed to the side surface 75c of the guide slit 74 of the guide rail 702 and a solid lubricant 94 fixed to the side surface 75d of the guide slit 74 of the guide rail 702, and is configured to slide relative to these solid lubricants 94. The plane 92 of the drive-side guide 852 is in contact with a solid lubricant 94 fixed to the side surface 75c of the guide slit 74 of the guide rail 702, and the plane 93 of the drive-side guide 852 is in contact with a solid lubricant 94 fixed to the side surface 75d of the guide slit 74 of the guide rail 702. Note that shims (not shown) may be interposed between each solid lubricant 94 and the inner surface of the guide slit 74 for dimensional adjustment.

[0067] In some embodiments, as shown for example in Figures 4, 8, and 9, the second guide mechanism 19 includes a plurality of bolts 96 for fastening a pair of guide rails 70 to the casing 9. In the illustrated exemplary embodiment, the second guide mechanism 19 includes a plurality of bolts 96 for fastening the upper part of guide rail 701 to the casing 9 and a plurality of bolts 96 for fastening the upper part of guide rail 702 to the casing 9. For example, as partially shown in Figure 9, a horizontal slit 98 may be formed at the upper part of each of the pair of guide rails 70, extending along the horizontal direction H and through which the shafts of the bolts 96 are inserted. In this case, the pair of guide rails 70 are configured to slide horizontally H relative to the casing 9.

[0068] In some embodiments, as shown in Figures 8 and 9, for example, each of the pair of guide rails 70 may include a component 70A that constitutes a guide slit 74 and a component 70B that is a separate component from component 70A and constitutes a horizontal slit 98. Component 70A and component 70B may, for example, be integrally molded separately.

[0069] In some embodiments, as shown in Figures 8 and 9, for example, the second guide mechanism 19 may include a mounting component 99 for attaching the guide rail 70 to the curved portion of the casing 9. The mounting component 99 includes a curved surface corresponding to the curved portion of the casing 9 and is attached to the casing 9 by a plurality of bolts 100. In this case, the plurality of bolts 96 may pass through the guide rail 70 and the mounting component 99 and be fastened to the casing 9.

[0070] Here, we will explain the effects of the second guide mechanism 19 in the steam valve 1 according to the embodiment shown in Figures 4 to 10.

[0071] Regarding the pin 27 that connects the pair of arm sections 48 and the link 28, the pair of guide rails 70 restrict the displacement of the pin 27 in the horizontal direction H, which intersects the axial direction of the pin 27. This suppresses uneven contact between the rod 24 that transmits power from the actuator 14 to the knuckle 26 and its surroundings, or between the knuckle 26 and its surroundings. Furthermore, since the pair of arm sections 48 and the link 28 are located between the pair of guide rails 70, maintenance of the second guide mechanism 19 is easy because it does not require the effort of releasing the pin connection between the pair of arm sections 48 and the link 28 and disassembling the link mechanism 16.

[0072] Furthermore, the solid lubricant 94 allows the knuckle 26 to move smoothly in the vertical direction, enabling smooth opening and closing of the valve in the steam valve 1. In addition, wear on the pin 27 side of the pin 27 can be suppressed when the pin 27 moves vertically within the guide slit 74. Moreover, since the solid lubricant 94 can be easily replaced even if it wears out, the maintainability of the second guide mechanism 19 can be improved.

[0073] Furthermore, since the second guide mechanism 19 is equipped with a pair of drive-side guides 85, the contact area between the pin 27 side configuration and the guide rail 70 side configuration can be increased compared to the case where the outer circumferential surface of the pin 27 slides against the configuration on the guide rail 70 side. As a result, when the pin 27 side configuration slides against the configuration on the guide rail 70 side, it is possible to suppress the localized large force acting on the sliding part, and thus prevent damage to the second guide mechanism 19.

[0074] Furthermore, since the outer surface 56 of the drive-side guide 851 includes a pair of planes 92, 93 facing the inner surface 75 of the guide slit 74 of the guide rail 701, and the outer surface 86 of the drive-side guide 852 includes a pair of planes 92, 93 facing the inner surface 75 of the guide slit 74 of the guide rail 702, the effect of increasing the contact area between the pin 27 side configuration and the guide rail 70 side configuration can be enhanced. As a result, when the pin 27 side configuration slides against the guide rail 70 side configuration, it is possible to suppress the localized large force acting on the sliding part, and damage to the second guide mechanism 19 can be effectively suppressed.

[0075] Furthermore, since the second guide mechanism 19 is equipped with bushings 89 fitted into the through holes 58 of each of the pair of drive-side guides 85, even if the bushings 89 wear out, only the bushings 89 can be replaced, improving the maintainability of the second guide mechanism 19. In addition, by using a material with a low coefficient of friction for the bushings 89, wear of the pins 27 can be suppressed.

[0076] Furthermore, since the second pin member 82 and the third pin member 84 are configured as separate parts from the first pin member 80 that penetrates the pair of arm portions 48 and the link 28, the second pin member 82 and the third pin member 84 can be replaced while maintaining the state in which the pair of arm portions 48 and the link 28 are pin-connected by the first pin member 80 (without disassembling the pair of arm portions 48, the link 28 and the first pin member 80). This improves the maintainability of the second guide mechanism 19. In addition, the steam valve 1 can also be realized by retrofitting the second pin member 82, the third pin member 84 and the second guide mechanism 19 to an existing steam valve equipped with the first pin member 80.

[0077] Furthermore, as explained using Figure 10, etc., the coefficient of friction between the bush 89 and the pin 27 (more specifically, the coefficient of friction between the solid lubricant 38 provided on the inner circumferential surface 89a of the bush 89 and the surface 27s of the pin 27, the coefficient of friction between the solid lubricant 38 provided on the surface 27s of the pin 27 facing the inner circumferential surface 89a of the bush 89 and the inner circumferential surface 89a of the bush 89, or the coefficient of friction between the inner circumferential surface 89a of the bush 89 and the surface 27s of the pin 27) can be reduced. As a result, even if the direction of the force transmitted from the pair of levers 30 to the pair of drive-side guides 85 via the pin 27 is in an oblique direction that intersects with the vertical and horizontal directions, the rotation of the pair of drive-side guides 85 around the axis of the pin 27 can be suppressed. As a result, uneven contact between the drive-side guide 85 and the inner surface of the guide slit 74 or the solid lubricant 94 formed on the inner surface of the guide slit 74 can be suppressed.

[0078] This disclosure is not limited to the embodiments described above, but also includes modified forms of the embodiments described above, as well as forms that combine these forms as appropriate.

[0079] For example, in some of the embodiments described above, the valve stem 12 and the connecting member 35 were configured as separate parts, but the valve stem 12 and the connecting member 35 (connecting portion) may be configured as a single integrally molded part.

[0080] Furthermore, in some embodiments, as shown in Figure 11, for example, the first guide mechanism 18 may not include either of the pair of guide rails 40 described above. The steam valve 1 according to the exemplary form shown in Figure 11 differs from the steam valve 1 according to Figure 3 in that it does not include a guide rail 40 on the side of one end 34a of the pin 34, and does not include a reinforcing plate 42, but the other basic configurations are the same as those shown in Figure 3.

[0081] Even in this configuration, the guide rail 40 on the other end 34b side of the pin 34 that pin-connects the pair of levers 30 and the connecting member 35 restricts the displacement of the pin 34 in the horizontal direction intersecting the axial direction of the pin 34, thereby suppressing uneven contact between the valve stem 12, which is integrally provided with the connecting member 35, and its surroundings. Furthermore, since one of the pair of levers 30 is located between the guide rail 40 on the other end 34b side of the pin 34 and the connecting member 35, compared to the configuration described in Patent Document 1, maintenance of the first guide mechanism 18 is easier because it does not require the effort of releasing the pin connection between one of the pair of levers 30 and the connecting member 35 and disassembling the link mechanism 16. In addition, when installing the guide rail 40 described in this embodiment on an existing steam valve that does not have the guide rail 40 described in this embodiment installed, it is easy to add the first guide mechanism 18 without the effort of releasing the pin connection between the pair of levers 30 and the connecting member 35 and disassembling the link mechanism.

[0082] Furthermore, even in the embodiment shown in Figure 5, for example, the first guide mechanism 18 does not need to include either one of the pair of guide rails 401 and 402. For example, if the first guide mechanism 18 includes a guide rail 401, a drive-side guide 551, and a second pin member 52, the first guide mechanism 18 does not need to include a guide rail 402, a reinforcing plate 42, a drive-side guide 552, and a third pin member 54. Also, if the first guide mechanism 18 includes a guide rail 402, a drive-side guide 552, and a third pin member 54, the first guide mechanism 18 does not need to include a guide rail 401, a reinforcing plate 42, a drive-side guide 551, and a second pin member 52.

[0083] Furthermore, in the embodiment shown in Figure 8, for example, the second guide mechanism 19 does not need to include either one of the pair of guide rails 701 and 702. For example, if the second guide mechanism 19 includes a guide rail 701, a drive-side guide 851, and a second pin member 82, the second guide mechanism 19 does not need to include a guide rail 702, a drive-side guide 852, and a third pin member 84. Also, if the second guide mechanism 19 includes a guide rail 702, a drive-side guide 852, and a third pin member 84, the second guide mechanism 19 does not need to include a guide rail 701, a drive-side guide 851, and a second pin member 82.

[0084] The contents described in each of the above embodiments can be understood, for example, as follows:

[0085] [1] A steam valve according to at least one embodiment of the present disclosure (e.g., the steam valve 1 described above) is A casing (e.g., the casing 9 above) on which a valve seat (e.g., the valve seat 8 above) is formed, A valve body (for example, the valve body 10 described above) that can contact the valve seat, A valve stem (for example, the valve stem 12 described above) connected to the valve body and extending in the vertical direction, An actuator (for example, the actuator 14 described above) and A link mechanism (for example, the link mechanism 16 described above) for transmitting power from the actuator to the valve stem, A guide mechanism (for example, the first guide mechanism 18 described above) that guides the movement of the valve stem in the vertical direction, Equipped with, The aforementioned link mechanism is A pair of levers (for example, the pair of levers 30 described above), A connecting portion (for example, the connecting member 35 described above) is provided integrally with the valve stem at the end of the valve stem opposite to the valve body, located between the pair of levers, A pin (for example, the pin 34 described above) that connects the pair of levers and the connecting portion, Includes, The guide mechanism includes guide rails (for example, the pair of guide rails 40 described above), One of the pair of levers is located between the guide rail and the connecting portion. The guide rail is configured to restrict the displacement of the pin in a horizontal direction (for example, the horizontal direction H described above) that intersects the axial direction of the pin.

[0086] According to the steam valve described in [1] above, the guide rail restricts the displacement of the pin that pin-connects the pair of levers and the connecting part in the horizontal direction intersecting the axial direction of the pin, thereby suppressing uneven contact between the valve stem, which is integrally provided with the connecting part, and its surroundings. Furthermore, since one of the pair of levers is located between the guide rail and the connecting part, compared to the configuration described in Patent Document 1 (a configuration in which the guide mechanism is located between the pair of levers in the axial direction of the pin that pin-connects the pair of levers and the connecting member), maintenance of the guide mechanism is easier because it does not require the effort of releasing the pin connection between the pair of levers and the connecting part and disassembling the link mechanism. In addition, when installing the guide rail described in this embodiment on an existing steam valve that does not have the guide rail described in this embodiment installed, it is easy to add the guide mechanism without the effort of releasing the pin connection between the pair of arm parts and the link and disassembling the link mechanism.

[0087] [2] In some embodiments, the steam valve described in [1] above, The guide mechanism comprises a pair of guide rails, including the guide rail, The pair of levers and the connecting portion are located between the pair of guide rails. The pair of guide rails are configured to restrict the displacement of the pin in a horizontal direction intersecting the axial direction of the pin.

[0088] According to the steam valve described in [2] above, the pin that connects the pair of levers and the connecting part is restricted from moving horizontally in a direction intersecting the axial direction of the pin by a pair of guide rails, thereby enhancing the effect of suppressing uneven contact between the valve stem, which is integrally provided with the connecting part, and its surroundings. Furthermore, since the pair of levers and the connecting part are located between the pair of guide rails, compared to the configuration described in Patent Document 1, maintenance of the guide mechanism is easier because it does not require the effort of releasing the pin connection between the pair of levers and the connecting part and disassembling the link mechanism.

[0089] [3] In some embodiments, the steam valve described in [2] above, Each of the pair of guide rails includes a guide slit (for example, the guide slit 44 described above) for guiding the pin in the vertical direction. The pin includes a portion located inside the guide slit of one of the pair of guide rails (for example, the one end 34a described above) and a portion located inside the guide slit of the other of the pair of guide rails (for example, the other end 34b described above).

[0090] According to the steam valve described in [3] above, the movement of the pin is guided vertically by the guide slit, so uneven contact between the valve stem and its surroundings can be effectively suppressed.

[0091] [4] In some embodiments, the steam valve described in [3] above, A solid lubricant (for example, the solid lubricant 64 described above) is provided on the inner surface of the guide slit in each of the pair of guide rails.

[0092] According to the steam valve described in [4] above, the solid lubricant allows the pin to move smoothly in the vertical direction, enabling smooth opening and closing of the valve. Furthermore, wear on the pin-side components when the pin moves vertically within the guide slit can be suppressed. In addition, even if the solid lubricant wears out, replacing the solid lubricant can suppress uneven contact between the valve stem and its surroundings while maintaining the smooth opening and closing operation of the valve, thereby improving the maintainability of the guide mechanism.

[0093] [5] In some embodiments, the steam valve described in [3] or [4] above, The system further comprises a pair of drive-side guides (for example, the pair of drive-side guides 55 described above), One of the pair of drive-side guides (for example, the drive-side guide 551 described above) is attached to the outer circumferential surface of the pin at one end of the pin and is located inside the guide slit of one of the pair of guide rails. The other of the pair of drive-side guides (for example, the drive-side guide 552 described above) is mounted on the outer circumferential surface of the pin at the other end of the pin and is located inside the guide slit of the other guide rail of the pair of guide rails.

[0094] According to the steam valve described in [5] above, the contact area between the pin-side component and the guide rail-side component can be increased compared to the case where the outer surface of the pin slides against the guide rail-side component. Therefore, when the pin-side component slides against the guide rail-side component, it is possible to suppress the localized large force acting on the sliding part, thereby suppressing damage to the guide mechanism.

[0095] [6] In some embodiments, the steam valve described in [5] above, The outer surface of one of the pair of drive-side guides includes a pair of planes (for example, the planes 62, 63 described above) that face the inner surface of the guide slit of one of the pair of guide rails, The outer surface of the other of the pair of drive-side guides includes a pair of planes (for example, the planes 63, 63 described above) that face the inner surface of the guide slit of the other of the pair of guide rails.

[0096] The steam valve described in [6] above enhances the effect of increasing the contact area between the pin-side component and the guide rail-side component compared to the case where the outer surface of the pin slides against the guide rail-side component. As a result, when the pin-side component slides against the guide rail-side component, it is possible to suppress the localized large force acting on the sliding part, and thus effectively suppress damage to the guide mechanism.

[0097] [7] In some embodiments, the steam valve described in [5] or [6] above, Each of the pair of drive-side guides has a through hole (for example, the through hole 58 described above) through which the pin passes. The system further includes bushings (for example, the bushings 59 described above) fitted into the through holes of each of the pair of drive-side guides.

[0098] According to the steam valve described in [7] above, even if the bushing wears out, only the bushing can be replaced, thus improving the maintainability of the guide mechanism. In addition, by using a material with a low coefficient of friction for the bushing, wear of the pin can be suppressed.

[0099] [8] In some embodiments, the steam valve described in [7] above, A solid lubricant (for example, the solid lubricant 36 described above) is provided on the inner circumferential surface of the bush or on the surface of the pin facing the inner circumferential surface of the bush, or the bush is formed of a solid lubricant.

[0100] As described in [8] above, by applying a solid lubricant, the coefficient of friction between the bush and the pin (more specifically, the coefficient of friction between the solid lubricant provided on the inner surface of the bush and the surface of the pin, the coefficient of friction between the solid lubricant provided on the surface of the pin facing the inner surface of the bush and the inner surface of the bush, or the coefficient of friction between the inner surface of the bush and the surface of the pin) can be reduced. As a result, even if the direction of the force transmitted from the pair of levers to the pair of drive-side guides via the pin is in an oblique direction that intersects the vertical and horizontal directions, the rotation of the pair of drive-side guides around the axis of the pin can be suppressed. As a result, uneven contact between the drive-side guides and the inner surface of the guide slit or the solid lubricant formed on the inner surface of the guide slit can be suppressed.

[0101] [9] In some embodiments, in the steam valve described in any of [3] to [8] above, The pin includes a first pin member (for example, the first pin member 50 described above) that penetrates the pair of levers and the connecting portion, a second pin member (for example, the second pin member 52 described above) connected to one end of the first pin member, and a third pin member (for example, the third pin member 54 described above) connected to the other end of the first pin member. The second pin member includes a portion located inside the guide slit of one of the pair of guide rails (for example, the end of the second pin member 52 opposite to the first pin member 50), and the third pin member includes a portion located inside the guide slit of the other of the pair of guide rails (for example, the end of the third pin member 54 opposite to the first pin member 50).

[0102] According to the steam valve described in [9] above, the second and third pin members are configured as separate parts from the first pin member that penetrates the pair of levers and the connecting part. Therefore, the second and third pin members can be replaced while maintaining the state in which the pair of levers and the connecting part are pin-connected by the first pin member (without disassembling the pair of levers, the connecting part and the first pin member). This improves the maintainability of the guide mechanism. Furthermore, the steam valve described in [9] above can also be realized by retrofitting the second and third pin members and the pair of guide rails to an existing steam valve equipped with the first pin member.

[0103]

[10] In some embodiments, in the steam valve described in any of [3] to [8] above, The aforementioned pin is a single, integrally molded part.

[0104] The steam valve described in

[10] above can reduce the number of parts compared to the steam valve described in [9] above.

[0105]

[11] A steam valve according to at least one embodiment of the present disclosure (e.g., the steam valve 1 described above) is A casing (e.g., the casing 9 above) on which a valve seat (e.g., the valve seat 8 above) is formed, A valve body (for example, the valve body 10 described above) that can contact the valve seat, A valve stem (for example, the valve stem 12 described above) connected to the valve body and extending in the vertical direction, An actuator (for example, the actuator 14 described above) and A link mechanism (for example, the link mechanism 16 described above) for transmitting power from the actuator to the valve stem, A steam valve equipped with, The aforementioned link mechanism is A knuckle (for example, the knuckle 26 described above) includes a pair of arm sections (for example, the pair of arm sections 48 described above) and moves along the vertical direction by the power of the actuator, A link (for example, the link 28 described above) has one end located between the pair of arm portions, A pin (for example, the pin 27 described above) connects the pair of arm portions and one end of the link, Equipped with, The steam valve is equipped with a guide mechanism (for example, the second guide mechanism 19 described above) that guides the movement of the knuckle in the vertical direction. The guide mechanism includes guide rails (for example, the pair of guide rails 70 described above), One of the pair of arm portions is located between the guide rail and the one end of the link, The guide rail is configured to restrict the displacement of the pin in a horizontal direction (for example, the horizontal direction H described above) that intersects the axial direction of the pin.

[0106] According to the steam valve described in

[11] above, the guide rail restricts the horizontal displacement of the pin that connects the pair of arms and the link, intersecting the axial direction of the pin. This suppresses uneven contact between the component that transmits the power of the actuator to the knuckle (for example, the rod in the above embodiment) and its surroundings, or between the knuckle and its surroundings. Furthermore, since one of the pair of arms is located between the guide rail and one end of the link, maintenance of the guide mechanism is easy without the effort of releasing the pin connection between the pair of arms and the link and disassembling the link mechanism. Additionally, when installing the guide rail described in this embodiment on an existing steam valve that does not have the guide rail described in this embodiment installed, it is easy to add the guide mechanism without the effort of releasing the pin connection between the pair of arms and the link and disassembling the link mechanism.

[0107]

[12] In some embodiments, the steam valve described in

[11] above, The guide mechanism comprises a pair of guide rails, including the guide rail, The pair of arm portions and the one end of the link are located between the pair of guide rails. The pair of guide rails are configured to restrict the displacement of the pin in a horizontal direction intersecting the axial direction of the pin.

[0108] According to the steam valve described in

[12] above, the pin connecting the pair of arms and one end of the link is restricted from being displaced horizontally by a pair of guide rails intersecting the axial direction of the pin. This enhances the effect of suppressing uneven contact between the component that transmits the power of the actuator to the knuckle and its surroundings, or between the knuckle and its surroundings. Furthermore, since the pair of arms and one end of the link are located between the pair of guide rails, compared to the configuration described in Patent Document 1, maintenance of the guide mechanism is easier because it does not require the effort of releasing the pin connection between the pair of arms and the link and disassembling the link mechanism.

[0109]

[13] In some embodiments, the steam valve described in

[12] above, Each of the pair of guide rails includes a guide slit (for example, the guide slit 74 described above) for guiding the pin in the vertical direction. The pin includes a portion located inside the guide slit of one of the pair of guide rails (for example, the one end 27a described above), and the other end of the pin includes a portion located inside the guide slit of the other of the pair of guide rails (for example, the other end 27b described above).

[0110] According to the steam valve described in

[13] above, the movement of the pin is guided vertically by the guide slit, so that uneven contact between the component that transmits the power of the actuator to the knuckle (for example, the rod in the embodiment described above) and its surroundings, or between the knuckle and its surroundings, can be suppressed.

[0111]

[14] In some embodiments, the steam valve described in

[13] above, A solid lubricant (for example, the solid lubricant 94 described above) is provided on the inner surface of the guide slit in each of the pair of guide rails.

[0112] According to the steam valve described in

[14] above, the knuckle can be moved smoothly in the vertical direction by the solid lubricant, and the valve can be opened and closed smoothly. In addition, wear on the pin side of the structure can be suppressed when the pin moves vertically within the guide slit. Furthermore, since the solid lubricant can be easily replaced even when it is worn out, the maintainability of the guide mechanism can be improved.

[0113]

[15] In some embodiments, the steam valve described in

[13] or

[14] above, It further includes a pair of drive-side guides, One of the pair of drive-side guides (for example, the drive-side guide 851 described above) is mounted on the outer circumferential surface of the pin at one end of the pin and is located inside the guide slit of one of the pair of guide rails. The other of the pair of drive-side guides (for example, the drive-side guide 852 described above) is mounted on the outer circumferential surface of the pin at the other end of the pin and is located inside the guide slit of the other guide rail of the pair of guide rails.

[0114] According to the steam valve described in

[15] above, the contact area between the pin-side component and the guide rail-side component can be increased compared to the case where the outer surface of the pin slides against the guide rail-side component. Therefore, when the pin-side component slides against the guide rail-side component, it is possible to suppress the localized large force acting on the sliding part, and thus prevent damage to the guide mechanism.

[0115]

[16] In some embodiments, the steam valve described in

[15] above, The outer surface of one of the pair of drive-side guides includes a pair of planes (for example, the planes 92, 93 described above) that face the inner surface of the guide slit of one of the pair of guide rails, The outer surface of the other of the pair of drive-side guides includes a pair of planes (for example, the planes 92 and 93 described above) that face the inner surface of the guide slit of the other of the pair of guide rails.

[0116] The steam valve described in

[16] above enhances the effect of increasing the contact area between the pin-side component and the guide rail-side component compared to the case where the outer surface of the pin slides against the guide rail-side component. As a result, when the pin-side component slides against the guide rail-side component, it is possible to suppress the localized large force acting on the sliding part, and thus effectively suppress damage to the guide mechanism.

[0117]

[17] In some embodiments, the steam valve described in

[15] or

[16] above, Each of the pair of drive-side guides has a through hole (for example, the through hole 88 described above) through which the pin passes. The system further includes bushings (for example, the bushings 89 described above) fitted into the through holes of each of the pair of drive-side guides.

[0118] According to the steam valve described in

[17] above, even if the bushing wears out, only the bushing can be replaced, thus improving the maintainability of the guide mechanism. In addition, by using a material with a low coefficient of friction for the bushing, wear of the pin can be suppressed.

[0119]

[18] In some embodiments, the steam valve described in

[17] above, A solid lubricant (for example, the solid lubricant 38 described above) is provided on the inner circumferential surface of the bush or on the surface of the pin facing the inner circumferential surface of the bush, or the bush is formed of a solid lubricant.

[0120] As described in

[18] above, by applying a solid lubricant, the coefficient of friction between the inner surface of the bush and the surface of the pin (more specifically, the coefficient of friction between the solid lubricant provided on the inner surface of the bush and the surface of the pin, the coefficient of friction between the solid lubricant provided on the surface of the pin facing the inner surface of the bush and the inner surface of the bush, or the coefficient of friction between the inner surface of the bush and the surface of the pin) can be reduced. As a result, even if the direction of the force transmitted from the pair of levers to the pair of drive-side guides via the pin is in an oblique direction that intersects the vertical and horizontal directions, the rotation of the pair of drive-side guides around the axis of the pin can be suppressed. As a result, uneven contact between the drive-side guides and the inner surface of the guide slit or the solid lubricant formed on the inner surface of the guide slit can be suppressed.

[0121]

[19] In some embodiments, in the steam valve described in any of

[13] to

[18] above, The pin includes a first pin member (for example, the first pin member 80 described above) that penetrates the pair of arm portions and one end of the link, a second pin member (for example, the second pin member 82 described above) connected to one end of the first pin member, and a third pin member (for example, the third pin member 84 described above) connected to the other end of the first pin member. The second pin member includes a portion of one of the pair of guide rails located inside the guide slit (for example, the end of the second pin member 82 opposite to the first pin member 80), and the third pin member includes a portion of the other of the pair of guide rails located inside the guide slit (for example, the end of the third pin member 84 opposite to the first pin member 80).

[0122] According to the steam valve described in

[19] above, the second and third pin members are configured as separate parts from the first pin member that penetrates the pair of arms and the link. Therefore, the second and third pin members can be replaced while maintaining the state in which the pair of arms and the link are connected by the first pin member (without disassembling the pair of arms, the link and the first pin member). This improves the maintainability of the guide mechanism. Furthermore, the steam valve described in

[19] above can also be realized by retrofitting the second and third pin members and the pair of guide rails to an existing steam valve equipped with the first pin member.

[0123]

[20] In some embodiments, in the steam valve described in any of

[13] to

[18] above, The aforementioned pin is a single, integrally molded part.

[0124] The steam valve described in

[20] above can reduce the number of parts compared to the steam valve described in

[19] above. [Explanation of Symbols]

[0125] 1. Steam valve 2. Steam Turbine System 4 Steam Turbine 6 Generators 8 valve seats 9 Casing 10 Valve body 12 valve stems 14 Actuators 16 Link mechanism 18. First Guide Mechanism 19. Second Guide Mechanism 20 Inlet channel 21 valve chambers 22 Outlet channel 24 rods 26 Knuckle 27,34 pins 27a,30a,34a One end 27b,30b,34b Other end 27s surface 28,32 links 30, 301, 302 levers 34s surface 35 Connecting member 36,38 Solid lubricants 40, 70, 401, 402, 701, 702 Guide rails 40A, 40B, 70A, 70B parts 40a 1st flat plate part 40b 2nd flat plate part 40c 3rd flat plate part 42 Reinforcement plate 44,74 Guide slits 45.75 Inner 45a,75a top surface 45b,75b Bottom surface 45c,45d,75c,75d Side 47 Base 48,481,482 Arm section 50,80 First pin member 52,82 Second pin member 54,84 Third pin member Washers 51, 60, 61, 90, 91 53, 66, 83, 96, 100 volts 55, 85, 551, 552, 851, 852 Drive side guide 56,86 External surface 58,88 through holes 59,89 Bush 59a Inner surface 62,63,92,93 plane 64,94,564 Solid lubricants 68,98 horizontal slits 89a Inner surface 99 Mounting parts

Claims

1. A casing in which a valve seat is formed, A valve body that can contact the valve seat, A valve stem connected to the valve body and extending in the vertical direction, Actuator and A link mechanism for transmitting power from the actuator to the valve stem, A guide mechanism for guiding the movement of the valve stem in the vertical direction, Equipped with, The aforementioned link mechanism is A pair of levers, A connecting portion is provided integrally with the valve stem at the end of the valve stem opposite to the valve body, located between the pair of levers, A pin that connects the pair of levers and the connecting portion, Includes, The guide mechanism includes a guide rail, One of the pair of levers is located between the guide rail and the connecting portion. A steam valve, wherein the guide rail is configured to restrict the displacement of the pin in a horizontal direction intersecting the axial direction of the pin.

2. The guide mechanism comprises a pair of guide rails, including the guide rail, The pair of levers and the connecting portion are located between the pair of guide rails. The steam valve according to claim 1, wherein the pair of guide rails are configured to restrict the displacement of the pin in a horizontal direction intersecting the axial direction of the pin.

3. Each of the pair of guide rails includes a guide slit for guiding the pin in the vertical direction. The steam valve according to claim 2, wherein the pin includes a portion located inside the guide slit of one of the pair of guide rails and a portion located inside the guide slit of the other of the pair of guide rails.

4. The steam valve according to claim 3, wherein a solid lubricant is provided on the inner surface of the guide slit in each of the pair of guide rails.

5. It further includes a pair of drive-side guides, One of the pair of drive-side guides is attached to the outer circumferential surface of the pin at one end of the pin and is located inside the guide slit of one of the pair of guide rails. The steam valve according to claim 3, wherein the other of the pair of drive-side guides is attached to the outer circumferential surface of the pin at the other end of the pin and is located inside the guide slit of the other guide rail of the pair of guide rails.

6. The outer surface of one of the pair of drive-side guides includes a pair of planes facing the inner surface of the guide slit of one of the pair of guide rails, The steam valve according to claim 5, wherein the outer surface of the other of the pair of drive-side guides includes a pair of planes facing the inner surface of the guide slit of the other of the pair of guide rails.

7. Each of the pair of drive-side guides has a through hole through which the pin passes. The steam valve according to claim 5, further comprising bushings fitted into the through holes of each of the pair of drive-side guides.

8. The steam valve according to claim 7, wherein a solid lubricant is provided on the inner circumferential surface of the bush or on the surface of the pin facing the inner circumferential surface of the bush, or the bush is formed of a solid lubricant.

9. The pin includes a first pin member that penetrates the pair of levers and the connecting portion, a second pin member connected to one end of the first pin member, and a third pin member connected to the other end of the first pin member. The steam valve according to claim 3, wherein the second pin member includes a portion located inside the guide slit of one of the pair of guide rails, and the third pin member includes a portion located inside the guide slit of the other of the pair of guide rails.

10. The steam valve according to claim 3, wherein the pin is a single, integrally molded part.

11. A casing in which a valve seat is formed, A valve body that can contact the valve seat, A valve stem connected to the valve body and extending in the vertical direction, Actuator and A link mechanism for transmitting power from the actuator to the valve stem, A steam valve equipped with, The aforementioned link mechanism is A knuckle including a pair of arm sections that moves vertically along the actuator by the power of the actuator, A link with one end positioned between the pair of arm portions, A pin that connects the pair of arm portions and one end of the link, Equipped with, The steam valve is equipped with a guide mechanism that guides the movement of the knuckle in the vertical direction. The guide mechanism includes a guide rail, One of the pair of arm portions is located between the guide rail and the one end of the link, A steam valve, wherein the guide rail is configured to restrict the displacement of the pin in a horizontal direction intersecting the axial direction of the pin.

12. The guide mechanism comprises a pair of guide rails, including the guide rail, The pair of arm portions and the one end of the link are located between the pair of guide rails. The steam valve according to claim 11, wherein the pair of guide rails are configured to restrict the displacement of the pin in a horizontal direction intersecting the axial direction of the pin.

13. Each of the pair of guide rails includes a guide slit for guiding the pin in the vertical direction. The steam valve according to claim 12, wherein one end of the pin is located inside the guide slit of one of the pair of guide rails, and the other end of the pin is located inside the guide slit of the other of the pair of guide rails.

14. The steam valve according to claim 13, wherein a solid lubricant is provided on the inner surface of the guide slit in each of the pair of guide rails.

15. It further includes a pair of drive-side guides, One of the pair of drive-side guides is attached to the outer circumferential surface of the pin at one end of the pin and is located inside the guide slit of one of the pair of guide rails. The steam valve according to claim 13, wherein the other of the pair of drive-side guides is attached to the outer circumferential surface of the pin at the other end of the pin and is located inside the guide slit of the other guide rail of the pair of guide rails.

16. The outer surface of one of the pair of drive-side guides includes a pair of planes facing the inner surface of the guide slit of one of the pair of guide rails, The steam valve according to claim 15, wherein the outer surface of the other of the pair of drive-side guides includes a pair of planes facing the inner surface of the guide slit of the other of the pair of guide rails.

17. Each of the pair of drive-side guides has a through hole through which the pin passes. The steam valve according to claim 15, further comprising bushings fitted into the through holes of each of the pair of drive-side guides.

18. The steam valve according to claim 17, wherein a solid lubricant is provided on the inner circumferential surface of the bush or on the surface of the pin facing the inner circumferential surface of the bush, or the bush is formed of a solid lubricant.

19. The pin includes a first pin member that penetrates the pair of arm portions and one end of the link, a second pin member connected to one end of the first pin member, and a third pin member connected to the other end of the first pin member. The steam valve according to claim 13, wherein the second pin member includes a portion located inside the guide slit of one of the pair of guide rails, and the third pin member includes a portion located inside the guide slit of the other of the pair of guide rails.

20. The steam valve according to claim 13, wherein the pin is a single, integrally molded part.

Images