Machining implement and machining method

Abstract

Provided are: a machining implement having a simple configuration with which a polishing surface can be caused to contact a target surface with an even force; and a machining method. The present invention is configured such that: a polishing part (210) and a traction part (220) are provided; the polishing part (210) has a second axis (L2) as the central axis and comprises an outer peripheral surface (211a) fitted with the shape of a valve seat (112a); the outer peripheral surface (211a) includes a polishing surface for polishing the valve seat (112a); and the traction part (220) pulls the central location of the polishing part (210) in the prescribed direction, with the outer peripheral surface (211a) of the polishing part (210) facing the valve seat (112a).

Description

Processing tools and processing methods

[0001] The present disclosure relates to processing tools and processing methods.

[0002] For example, in a valve that shuts off a fluid, the adhesion between the valve body and the valve seat is important, and therefore, in order to improve the adhesion, the valve seat is sometimes subjected to lapping (grinding) using a processing tool (see, for example, Patent Document 1).

[0003] Japanese Patent Application Publication No. 9-242518

[0004] Unlike the method described in Patent Document 1, conventional methods sometimes require the installation of a jig to support centering of the polishing tool. This requires the jig to be removed and reinstalled each time maintenance work is performed on the polishing surface of the polishing tool (e.g., replacing sandpaper), resulting in time-consuming maintenance work. Furthermore, in this conventional method, the polishing tool is pressed against the valve seat by manual force, which can easily cause the polishing tool to shift or tip over. If the polishing tool shifts or tips over, it can become difficult to press the polishing surface of the polishing tool against the valve seat with uniform force, or the polished surface can become uneven, potentially resulting in poor lapping results.

[0005] Furthermore, the method described in Patent Document 1 uses a large-scale device, and therefore installation of the device may require a complicated process.

[0006] The present disclosure has been made in consideration of the above circumstances, and aims to provide a processing tool and processing method with a simple configuration that can bring the polishing surface into contact with the target surface with a uniform force.

[0007] In order to solve the above problems, the processing tool and processing method of the present disclosure employ the following means: A processing tool according to one aspect of the present disclosure is a processing tool for processing an inner circumferential surface having a first axis as a central axis and an inner diameter that decreases in a predetermined direction along the first axis, the processing tool comprising: a grinding unit and a pulling unit, the grinding unit having an outer circumferential surface having a second axis as a central axis and conforming to the shape of the inner circumferential surface, the outer circumferential surface including a grinding surface that grinds the inner circumferential surface, and the pulling unit configured to pull a center position of the grinding unit in the predetermined direction with the outer circumferential surface of the grinding unit facing the inner circumferential surface.

[0008] Furthermore, a processing method according to one aspect of the present disclosure is a processing method using the above-described processing tool, in which the pulling portion pulls the polishing portion in the predetermined direction, and the polishing portion rotates around the second axis.

[0009] According to the present disclosure, it is possible to provide a processing tool and a processing method having a simple configuration that can bring a polishing surface into contact with a target surface with a uniform force.

[0010] FIG. 1 is a partially cutaway perspective cross-sectional view of a steam valve to be processed by a processing tool according to an embodiment of the present disclosure; FIG. 2 is a longitudinal cross-sectional view of a steam valve to be processed by a processing tool according to an embodiment of the present disclosure; FIG. 3 is a longitudinal cross-sectional view of a steam valve on which a processing tool according to an embodiment of the present disclosure is installed (without a wire); FIG. 4 is a longitudinal cross-sectional view of a steam valve on which a processing tool according to an embodiment of the present disclosure is installed (with a wire); FIG. 5 is a side view of a processing tool according to an embodiment of the present disclosure; FIG. 6 is a front view of a towing portion of a processing tool according to an embodiment of the present disclosure; FIG. 7 is a front view of a towing portion of a processing tool according to an embodiment of the present disclosure; FIG. 8 is a front view of a towing portion of a processing tool according to an embodiment of the present disclosure;

[0011] <Regarding the Steam Valve> The steam valve 100 is a valve that is installed, for example, at the steam intake of a steam turbine and that allows or stops the passage of steam. As shown in Figures 1 and 2, the steam valve 100 includes a first casing 110, a second casing 120, and a valve section 130.

[0012] The first casing 110 is a member that defines a first valve chamber 111 and a communication flow path 112 therein.

[0013] The first valve chamber 111 is a space into which steam supplied from the outside is introduced via a steam inlet 113 formed in the first casing 110. The first valve chamber 111 is also used as a working space for lapping, which will be described later.

[0014] The communicating passage 112 is a passage for guiding steam that has flowed into the first valve chamber 111 to the second valve chamber 121, which will be described later. The communicating passage 112 extends along the first axis L1 and has a circular cross section in a plane substantially perpendicular to the first axis L1 (a cross section relative to the first axis L1). That is, the communicating passage 112 has a cylindrical inner circumferential surface with the first axis L1 as its central axis. An inlet portion of this inner circumferential surface (the inlet portion of the communicating passage 112) serves as a valve seat 112a. Here, the inlet portion of the communicating passage 112 can also be referred to as a portion of the communicating passage 112 adjacent to the first valve chamber 111, a boundary portion of the communicating passage 112 with the first valve chamber 111, or a connection portion of the communicating passage 112 with the first valve chamber 111.

[0015] The valve seat 112a is a surface that receives a valve disc 131 of the valve portion 130, which will be described later. The valve seat 112a has an inner diameter that decreases in a predetermined direction along the first axis L1. That is, the valve seat 112a narrows in the predetermined direction along the first axis L1. Here, the predetermined direction corresponds to the direction from the first valve chamber 111 to the communication passage 112 on the first axis L1 (the main steam flow direction). In the case of FIG. 2 , the first axis L1 extends along the left-right direction, and the predetermined direction is the direction from right to left along the first axis L1. The left-right direction in FIG. 2 corresponds to, for example, the actual horizontal direction, but this is an example and does not limit the attitude of the steam valve 100. The shape of the valve seat 112a may be, as long as the inner diameter decreases, for example, a tapered shape, a shape with rounded corners that are convex, a shape with rounded corners that are concave, or a combination of these.

[0016] An opening 114 is formed in the top of the first casing 110. The surface of the first casing 110 around the opening 114 is a flange surface 115. A lid 140 is attached to the flange surface 115. The lid 140 is fastened to the first casing 110 by, for example, bolts. In order to attach the lid 140, the flange surface 115 is machined to have a flat surface.

[0017] The second casing 120 is a member that defines a second valve chamber 121 therein. The second casing 120 is provided downstream of the first casing 110 in the main steam flow direction, and is connected to the first casing 110. Specifically, the second casing 120 is connected to a portion of the first casing 110 that defines the outlet portion of the communication flow path 112.

[0018] The second valve chamber 121 is a space to which the steam that has flowed into the first valve chamber 111 is guided via the communication passage 112. The second valve chamber 121 is also used as a working space for lapping, which will be described later.

[0019] An opening 124 is formed in the upper part of the second casing 120. The surface of the second casing 120 around the opening 124 is a flange surface 125. A lid 150 is attached to the flange surface 125. The lid 150 is fastened to the second casing 120 by, for example, bolts. In order to attach the lid 150, the flange surface 125 is machined to have a flat surface.

[0020] The valve unit 130 is a mechanism for allowing or blocking the flow of steam from the first valve chamber 111 toward the communicating flow path 112 by opening or closing the inlet (opening) of the communicating flow path 112. The valve unit 130 includes a valve body 131 and an arm 132.

[0021] The valve disc 131 is a component that actually opens and closes the inlet of the communicating flow path 112. The valve disc 131 has a disc shape that is curved convexly toward the first valve chamber 111. The valve disc 131 has an outer peripheral surface 131a that substantially matches the shape of the valve seat 112a (the inner peripheral surface of the inlet portion of the communicating flow path 112) and is configured to closely contact the valve seat 112a. More precisely, the valve seat 112a is lapped using a processing tool 200 (described later) so that the shape of the valve seat 112a substantially matches the shape of the outer peripheral surface 131a of the valve disc 131. Here, "substantially matching" means "a degree of shape accuracy that allows the surfaces (outer peripheral surface 131a) and the surface (valve seat 112a) to be completely in close contact" or "a degree of shape accuracy that allows the contact between the surfaces (outer peripheral surface 131a) and the surface (valve seat 112a) to properly shut off the flow of steam / to function as a stop valve." The valve body 131 only needs to have an outer peripheral surface 131a that matches the shape of the valve seat 112a, and the shape of the parts other than the outer peripheral surface 131a is not particularly limited.

[0022] The arm 132 is driven by a drive source (actuator) (not shown) to support the valve disc 131 and move the valve disc 131 between an open position and a closed position. The open position is indicated by the dotted line in FIG. 2 , where the outer circumferential surface 131 a of the valve disc 131 is not in close contact with the valve seat 112 a. The closed position is indicated by the solid line in FIG. 2 , where the outer circumferential surface 131 a of the valve disc 131 is in close contact with the valve seat 112 a. When the valve disc 131 is in the open position, steam flows from the first valve chamber 111 toward the communicating flow path 112. When the valve disc 131 is in the closed position, steam flowing from the first valve chamber 111 toward the communicating flow path 112 is blocked.

[0023] 3 and 4, the processing tool 200 is a tool for lapping the valve seat 112a formed in the first casing 110. As shown in FIGS. 3 to 5, the processing tool 200 includes a grinding unit 210 and a traction unit 220.

[0024] <<Regarding the Polishing Section>> The polishing section 210 is a section that actually polishes the valve seat 112a. The polishing section 210 has a polishing section main body 211 and an omnidirectional eyebolt 212 (connector).

[0025] The polishing unit main body 211 is a disk-shaped component with the second axis L2 as its central axis. The polishing unit main body 211 has an outer peripheral surface 211a. The outer diameter of the outer peripheral surface 211a decreases in a predetermined direction along the second axis L2, and its shape matches the shape of the valve seat 112a. Here, "match" includes "a state in which the shape of the outer peripheral surface 211a substantially matches the shape of the valve seat 112a" and "a state in which the shapes can be substantially matched by lapping (e.g., a state in which the shapes match macroscopically but surface roughness or waviness remains microscopically)." The outer peripheral surface 211a includes a polishing surface that actually contacts and polishes the valve seat 112a. The polishing surface may be formed over the entire circumference of the outer peripheral surface 211a or may be formed on only a portion of the outer peripheral surface 211a. Examples of the polishing surface include sandpaper or diamond paper attached to the outer peripheral surface 211a. The shape of the outer peripheral surface 211a of the polishing unit main body 211 substantially matches the shape of the outer peripheral surface 131a of the valve body 131, and by polishing the valve seat 112a with the outer peripheral surface 211a of the polishing unit main body 211, the shape of the valve seat 112a substantially matches the shape of the outer peripheral surface 131a of the valve body 131. In other words, the shape that serves as the master in processing is the shape of the outer peripheral surface 211a of the polishing unit main body 211.

[0026] An omnidirectional eyebolt 212 is attached to the center of the grinding unit body 211. The omnidirectional eyebolt 212 is attached so as to face the second casing 120 when machining the valve seat 112a. The omnidirectional eyebolt 212 has a bolt portion 212a and a ring portion 212b. The bolt portion 212a is fixed (fastened) to the grinding unit body 211 and does not move relative to the grinding unit body 211. The ring portion 212b is connected to the bolt portion 212a but is rotatable about the second axis L2 relative to the bolt portion 212a. In other words, the ring portion 212b is also rotatable about the second axis L2 relative to the grinding unit body 211.

[0027] 4 and 5 , the traction unit 220 is a part that applies a force to the grinding unit 210 to bring the outer circumferential surface 211 a of the grinding unit main body 211 into contact with the valve seat 112 a of the first casing 110 by pulling the grinding unit 210 in a predetermined direction. The traction unit 220 has a wire 221 (cord-like body), a traction mechanism 230, and a pulley 222 (hanging device).

[0028] The wire 221 is a deformable, elongated component that transmits the force generated by the traction mechanism 230 (the force that pulls the polishing unit 210 in a predetermined direction; hereinafter, simply referred to as the "traction force") to the polishing unit 210. The wire 221 connects the polishing unit 210 and the traction mechanism 230. Specifically, the wire 221 has a first end 221a and a second end 221b. The first end 221a is fastened to a ring 233a of the traction mechanism 230 (see FIG. 8), and the second end 221b is fastened to a ring portion 212b of the omnidirectional eyebolt 212 (see FIG. 5). Note that the wire 221 is merely an example, and any deformable, elongated component, such as a rope or chain, can be used as the cord-like member. In either case, the material of the cord-like member is not particularly limited as long as it can withstand the tension generated by the traction force.

[0029] The traction mechanism 230 is a mechanism that generates a traction force and applies the traction force to the wire 221. The traction mechanism 230 is installed in the second casing 120 of the steam valve 100. As shown in Figures 5 and 6, the traction mechanism 230 has a frame 231, a base plate 232, a movable plate 233, a pushing portion 234, at least one (e.g., two) gas springs 235 (first load means), and at least one (e.g., two) spring load applying portions 236 (second load means).

[0030] The frame 231 is a structure having a substantially rectangular portion and includes two frame shafts 231a (231a1, 231a2), a fixing plate 231b, and a fixing plate 231c. The frame shaft 231a is a rod-shaped component extending in the vertical direction in FIGS. 5 and 6. The shape of the frame shaft 231a is not limited to a round bar shape and may be, for example, a square bar shape. The extending direction of the frame shaft 231a is an example for explanation and does not limit the actual posture of the processing tool 200. The fixing plate 231b is a plate-shaped component extending in a direction substantially perpendicular to the extending direction of the frame shaft 231a (the left-right direction in FIG. 6). The fixing plate 231b connects the upper part of the frame shaft 231a1 and the upper part of the frame shaft 231a2. The fixing plate 231c is a plate-shaped component parallel to the fixing plate 231b. The fixed plate 231c connects the lower part of the frame shaft 231a1 and the lower part of the frame shaft 231a2.

[0031] The base plate 232 is a plate-shaped component extending in a direction substantially perpendicular to the extension direction of the frame shaft 231a (the left-right direction in FIG. 6 ). The base plate 232 also serves as a component for installing the traction mechanism 230 in the second casing 120. The base plate 232 is located between the fixed plates 231b and 231c, and the frame shaft 231a is inserted through and fixed to the frame shaft 231a. Therefore, the base plate 232 does not move relative to the frame shaft 231a (frame 231). The base plate 232 is installed and fixed to the flange surface 125 of the second casing 120. This allows the traction mechanism 230 to be installed in the second casing 120. Since the flange surface 125 is flat, the base plate 232 can be installed stably. Furthermore, the base plate 232 can be fixed with bolts (not shown) using bolt holes 125a provided in the flange surface 125. The flange surface 125 and the bolt holes 125 a are originally structures used when attaching the lid 150 to the second casing 120 .

[0032] The movable plate 233 is a plate-shaped component that is parallel to the base plate 232. The movable plate 233 is located between the fixed plate 231b and the base plate 232, and the frame shaft 231a is inserted through the movable plate 233 but is not fixed to the frame shaft 231a. Therefore, the movable plate 233 is slidable relative to the frame shaft 231a (frame 231) along the direction in which the frame shaft 231a extends. A ring 233a to which the second end 221b of the wire 221 is fastened is provided on the lower surface of the movable plate 233.

[0033] The pushing unit 234 is a mechanism that can push the movable plate 233 toward the base plate 232. The pushing unit 234 is provided above the movable plate 233. The pushing unit 234 has a pushing shaft 234a and a handle 234b provided at the upper end of the pushing shaft 234a. The pushing shaft 234a is a round bar-shaped part with a screw thread formed on its outer circumferential surface and is fitted into a screw hole formed in the fixed plate 231b of the frame 231. By gripping the handle 234b and turning the pushing shaft 234a, the pushing shaft 234a can be moved relative to the fixed plate 231b. The moving direction of the pushing shaft 234a is the same as the extending direction of the frame shaft 231a. At this time, the lower end of the pushing shaft 234 a is in contact with the movable plate 233 , so that by moving the pushing shaft 234 a toward the base plate 232 , the movable plate 233 can be pushed toward the base plate 232 .

[0034] The gas spring 235 is a component that applies a force to the movable plate 233 in a direction that moves the movable plate 233 away from the base plate 232. The gas spring 235 has a tube 235a and a rod 235b that extends from the tube 235a and moves back and forth relative to the tube 235a. The gas spring 235 is provided between the base plate 232 and the movable plate 233, with the tube 235a fixed to the base plate 232 and the rod 235b fixed to the movable plate 233. When the rod 235b is pushed into the tube 235a, the gas spring 235 generates a reaction force in a direction that causes the rod 235b to protrude from the tube 235a (in a direction that returns to its original position). Furthermore, the generated reaction force is constant regardless of the amount that the rod 235b is pushed. In the traction mechanism 230 of this embodiment, the reaction force of this gas spring 235 is used to apply a force to the movable plate 233 in a direction in which the movable plate 233 moves away from the base plate 232. Note that the gas spring 235 is just one example, and any component that generates a constant force when the distance between the base plate 232 and the movable plate 233 is within a predetermined range can be used as the first loading means.

[0035] The spring load applying portion 236 applies a force to the movable plate 233 in a direction that pushes the movable plate 233, to which force is applied by the gas spring 235, toward the base plate 232. The spring load applying portion 236 includes a threaded shaft 236a, a nut 236b, and a coil spring 236c. The threaded shaft 236a is a rod-shaped component having a thread formed on its outer circumferential surface and extending in the same direction as the frame shaft 231a. Its lower end is fixed to the base plate 232 and its upper end protrudes from the movable plate 233. The threaded shaft 236a is inserted through the movable plate 233 but is not fixed to the threaded shaft 236a. Therefore, the movable plate 233 is slidable relative to the threaded shaft 236a along the direction in which the threaded shaft 236a extends. The nut 236b is fitted to the portion of the threaded shaft 236a protruding from the movable plate 233. The coil spring 236c is provided so as to wind around the portion of the threaded shaft 236a between the movable plate 233 and the nut 236b.

[0036] In the spring load applying unit 236 configured as described above, when the nut 236b is turned in a predetermined direction, the nut 236b approaches the movable plate 233. As the nut 236b approaches the movable plate 233, the coil spring 236c is eventually compressed. As a result, a restoring force is generated by the coil spring 236c. The magnitude of this restoring force can be adjusted by the amount of compression of the coil spring 236c. In the traction mechanism 230 of this embodiment, the restoring force of the coil spring 236c is used to apply a force to the movable plate 233 in a direction that pushes the movable plate 233 toward the base plate 232. Note that the spring load applying unit 236 is just one example, and any component that can apply an adjustable force to the movable plate 233 can be used as the second loading means.

[0037] The pulley 222 is a component on which the wire 221 is hung. As shown in FIG. 4 , the wire 221 hung on the pulley 222 is bent by the pulley 222. As shown in FIG. 6 , the pulley 222 is located between the fixed plate 231c and the base plate 232, and is supported by the frame shaft 231a. The pulley 222 is movable relative to the frame 231. Examples of directions in which the pulley 222 can move include the direction in which the frame shaft 231a extends and / or a direction approximately perpendicular to that direction (for example, the direction in which the fixed plate 231c extends). Note that the pulley 222 may be supported by a portion other than the frame shaft 231a. Furthermore, the number of pulleys 222 may be plural.

[0038] <About Use of the Processing Tool> The processing tool 200 is used, for example, as follows. As shown in Figures 3 and 6, the base plate 232 of the traction mechanism 230 is fixed to the flange surface 125 of the second casing 120 with bolts (not shown). Then, as shown in Figure 7, the handle 234b of the pushing unit 234 is turned to move the movable plate 233 in a direction in which the movable plate 233 approaches the base plate 232, thereby generating a reaction force (a constant force) from the gas spring 235. In addition, the position of the nut 236b of the spring load applying unit 236 is adjusted to prevent the coil spring 236c from generating a restoring force.

[0039] The polishing unit 210 is supported so that the outer peripheral surface 211a of the polishing unit main body 211 contacts the valve seat 112a of the first casing 110. At this time, the outer peripheral surface 211a does not need to be in close contact with the valve seat 112a, and the outer peripheral surface 211a does not need to be pressed against the valve seat 112a.

[0040] Next, as shown in Figures 4, 5, and 8, the traction mechanism 230 and the polishing unit 210 are connected by the wire 221. In detail, the first end 221a of the wire 221 is fastened to the ring 233a of the movable plate 233, the middle portion of the wire 221 (the portion between the first end 221a and the second end 221b) is hung on the pulley 222 to bend the wire 221 by approximately 90 degrees, and the second end 221b of the wire 221 is fastened to the ring portion 212b of the omnidirectional eyebolt 212. At this time, no tension caused by the traction mechanism 230 is generated in the wire 221.

[0041] The portion of the wire 221 from the pulley 222 to the omnidirectional eyebolt 212 is preferably parallel to the first axis L1. This is to allow a traction force to be efficiently applied to the grinding unit main body 211 in the traction process described below. Therefore, the pulley 222 may be moved relative to the frame 231 so that the position of the pulley 222 substantially coincides with the position of the omnidirectional eyebolt 212 in a direction perpendicular to the first axis L1.

[0042] Next, as shown in FIG. 9 , the handle 234b of the pushing unit 234 is rotated in the opposite direction to the previous rotation to move the movable plate 233 away from the base plate 232. At this time, the wire 221 is set to a length that generates tension as the movable plate 233 returns. In other words, the wire 221 is set to a length that generates tension before the movable plate 233 is completely returned to its original position (a position where no reaction force from the gas spring 235 is generated). The position of the nut 236b of the spring load unit 236 is adjusted to a state where no restoring force from the coil spring 236c is generated. In this state, only the reaction force from the gas spring 235 is transmitted to the polishing unit 210 via the wire 221. The polishing unit body 211 of the polishing unit 210 is pulled in a predetermined direction by the force transmitted via the wire 221. This causes the outer peripheral surface 211a of the polishing unit body 211 to press against the valve seat 112a.

[0043] Next, as shown in FIG. 10 , the nut 236b is rotated to compress the coil spring 236c, generating a restoring force from the coil spring 236c. When the movable plate 233 is used as a reference, the restoring force from the coil spring 236c acts as a force that resists the reaction force from the gas spring 235. Therefore, when the restoring force from the coil spring 236c is generated, the movable plate 233 is slightly pushed toward the base plate 232. This loosens the wire 221 by the amount of movement of the movable plate 233, reducing the tension generated in the wire 221. In other words, the tractive force transmitted by the wire 221 is reduced. By utilizing this, the amount of compression of the coil spring 236c can be adjusted to adjust the tractive force transmitted to the polishing unit main body 211 via the wire 221. This allows the outer peripheral surface 211a of the polishing unit main body 211 to be pressed against the valve seat 112a with an appropriate force.

[0044] As described above, the process of generating a strong tension in the wire 221 by the reaction force of the gas spring 235 and then reducing that tension by the restoring force of the coil spring 236c, thereby pulling the grinding unit body 211 with an appropriate pulling force, is called the "pulling process." This pulling process is performed, for example, by an operator. Note that if the pulling force is excessively weak, the grinding unit body 211 may tilt. Also, if the pulling force is excessively weak, grinding does not progress (grinding is difficult) in the rotation process described below. Also, if the pulling force is excessively strong, it becomes difficult to rotate the grinding unit body 211 about the second axis L2 in the rotation process described below.

[0045] After the traction step, the grinding unit main body 211 is rotated around the second axis L2 from the side of the first valve chamber 111. This step is called the "rotation step." The rotation step is performed, for example, by an operator. As a result, the grinding unit main body 211 rotates with the outer peripheral surface 211a pressed against the valve seat 112a, so the valve seat 112a is polished by the polishing surface included in the outer peripheral surface 211a. At this time, because the wire 221 and the grinding unit main body 211 are connected by the omnidirectional eyebolt 212, the wire 221 does not twist even when the grinding unit main body 211 rotates.

[0046] The rotation process is characterized in that the polishing unit body 211 is automatically centered with respect to the valve seat 112a. Centering will be described in detail below.

[0047] The valve seat 112a has an inner diameter that decreases in a predetermined direction along the first axis L1. The outer diameter of the outer peripheral surface 211a of the grinding body 211 decreases in a predetermined direction along the second axis L2, and its shape matches the shape of the valve seat 112a. When the grinding body 211 having such a shape is pulled in a predetermined direction, the outer peripheral surface 211a of the grinding body 211 faces and comes into contact with the valve seat 112a. At this time, a traction force is applied to the center of the grinding body 211, so the traction force is uniformly distributed across the outer peripheral surface 211a of the grinding body 211.

[0048] In this state, by rotating the grinder body 211 around the second axis L2, the grinder body 211 moves radially relative to the valve seat 112a so that the outer peripheral surface 211a of the grinder body 211 fits onto the valve seat 112a. As a result, the second axis L2, which is the central axis of the grinder body 211, coincides with the first axis L1, which is the central axis of the valve seat 112a, and they are automatically aligned.

[0049] By rotating the polishing body 211 while pulling the center position of the polishing body 211 in the centered state, lapping is performed with the outer peripheral surface 211a of the polishing body 211 in contact with the valve seat 112a with uniform force. As a result, the valve seat 112a is polished uniformly by the outer peripheral surface 211a of the polishing body 211.

[0050] According to this embodiment, the following effects are achieved.

[0051] The inner diameter of the valve seat 112a decreases in a predetermined direction, and the outer peripheral surface 211a of the polishing body 211 conforms to the shape of the valve seat 112a. Furthermore, the center position of the polishing body 211 is pulled in a predetermined direction by the towing unit 220 while the outer peripheral surface 211a of the polishing body 211 faces the valve seat 112a. Therefore, when the towed polishing body 211 is rotated around the second axis L2, the polishing body 211 moves relative to the valve seat 112a and automatically aligns with the valve seat 112a so that the outer peripheral surface 211a fits the valve seat 112a. Therefore, when the polishing body 211 is pulled, the outer peripheral surface 211a (more specifically, the polishing surface) contacts the valve seat 112a with a uniform force. When the polishing body 211 is rotated around the second axis L2 in this state, the valve seat 112a is uniformly polished by the outer peripheral surface 211a of the polishing body 211.

[0052] In addition, the polishing unit main body 211 can be automatically centered with respect to the valve seat 112a due to the simple configuration of the shape of the valve seat 112a, the outer surface 211a of the polishing unit main body 211 that fits that shape, and the polishing unit main body 211 that is pulled to its central position.

[0053] In addition, the omnidirectional eyebolt 212 connects the grinding unit main body 211 to the wire 221 so that it can rotate freely around the second axis L2, so that only the grinding unit main body 211 can be rotated around the second axis L2 without causing twisting in the wire 221.

[0054] In addition, the tension generated in the wire 221 can be adjusted by the combination of the gas spring 235 and the spring load applying portion 236 .

[0055] Furthermore, since the wire 221 is bent by the pulley 222, the degree of freedom in arranging the position of the first end 221a of the wire 221 connected to the traction mechanism 230 increases.

[0056] Furthermore, since the pulley 222 is movable, the position of the first end 221a and / or the second end 221b of the wire 221 can be adjusted.

[0057] Although the lapping of the valve seat 112a of the steam valve 100 has been described as an example, the processing tool 200 and processing method according to the present disclosure can also be applied to other structures having an inner circumferential surface whose inner diameter decreases in a predetermined direction. An example of such other structures is a welding groove provided at the end of a pipe or the like when butt welding the pipe. In this case, the processing tool 200 can be used to process or correct the groove surface.

[0058] The processing tool and processing method according to one embodiment of the present disclosure described above can be understood, for example, as follows.

[0059] A processing tool (200) according to a first aspect of the present disclosure is a processing tool (200) for processing an inner circumferential surface (112a) having a first axis (L1) as a central axis and an inner diameter that decreases in a predetermined direction along the first axis (L1), and includes a polishing unit (210) and a pulling unit (220), wherein the polishing unit (210) has an outer circumferential surface (211a) having a second axis (L2) as a central axis and conforming to the shape of the inner circumferential surface (112a), the outer circumferential surface (211a) including a polishing surface that polishes the inner circumferential surface (112a), and the pulling unit (220) is configured to pull the center position of the polishing unit (210) in the predetermined direction with the outer circumferential surface (211a) of the polishing unit (210) facing the inner circumferential surface (112a).

[0060] According to the processing tool (200) of this embodiment, the inner diameter of the inner peripheral surface (112a) decreases in a predetermined direction, the outer peripheral surface (211a) of the polishing section (210) fits the shape of the inner peripheral surface (112a), and the center position of the polishing section (210) is pulled in a predetermined direction by the pulling section (220) with the outer peripheral surface (211a) of the polishing section (210) facing the inner peripheral surface (112a). Therefore, when the pulled polishing section (210) is rotated around the second axis (L2), the polishing section (210) moves relative to the inner peripheral surface (112a) so that the outer peripheral surface (211a) of the polishing section (210) fits into the inner peripheral surface (112a), and is automatically centered. Therefore, when the polishing unit (210) is pulled, the outer peripheral surface (211 a) (more specifically, the polishing surface) of the polishing unit (210) comes into contact with the inner peripheral surface (112 a) with a uniform force. If the polishing unit (210) is rotated around the second axis (L2) in this state, the inner peripheral surface (112 a) is uniformly polished by the outer peripheral surface (211 a) of the polishing unit (210). Furthermore, the polishing unit (210) can be automatically centered with respect to the inner peripheral surface (112 a) through a simple configuration including the shape of the inner peripheral surface (112 a), the outer peripheral surface (211 a) of the polishing unit (210) that matches that shape, and the polishing unit (210) whose center position is pulled.

[0061] In the processing tool (200) according to the second aspect of the present disclosure, in the first aspect, the polishing section (210) has a polishing section main body (211) including the outer circumferential surface (211a), and a connecting tool (212) provided on the polishing section main body (211) and to which the towing section (220) is connected, and the connecting tool (212) connects the polishing section main body (211) to the towing section (220) so as to be rotatable around the second axis (L2).

[0062] According to the processing tool (200) of this embodiment, the connecting tool (212) connects the polishing unit body (211) to the traction unit (220) so that the polishing unit body (211) can be rotated freely around the second axis (L2) relative to the traction unit (220), so that only the polishing unit body (211) can be rotated around the second axis (L2) without moving the traction unit (220).

[0063] In the processing tool (200) according to the third aspect of the present disclosure, in the second aspect, the traction section (220) has a cord-like body (221) connected to the connecting tool (212) and transmitting a traction force to the polishing section main body (211), and a traction mechanism (230) that imparts a force to the cord-like body (221) to pull the polishing section main body (211).

[0064] The processing tool (200) according to this embodiment includes a cord (221) that transmits a pulling force to the polishing unit main body (211) and a pulling mechanism (230) that applies a pulling force to the polishing unit main body (211) to the cord (221), so that even if the pulling mechanism (230) is installed in a location away from the polishing unit main body (211) (for example, a location where the pulling mechanism (230) can be easily installed stably), the pulling force can be transmitted to the polishing unit main body (211) via the cord (221). Examples of the cord (221) include a rope and a chain.

[0065] In the processing tool (200) according to the fourth aspect of the present disclosure, in the third aspect, the traction mechanism (230) has a first loading means (235) that applies a force to the cord-like body (221) to pull the polishing body (211) in the predetermined direction, and a second loading means (236) that applies a force to the cord-like body (221) to release the tension generated in the cord-like body (221) by the first loading means (235).

[0066] According to the processing tool (200) of this embodiment, the traction mechanism (230) has a first loading means (235) that applies a force to the cord-like body (221) to pull the polishing part main body (211) in a predetermined direction, and a second loading means (236) that applies a force to the cord-like body (221) to relax the tension generated in the cord-like body (221) by the first loading means (235). Therefore, the tension generated in the cord-like body (221) can be adjusted by combining the first loading means (235) and the second loading means (236).

[0067] The processing tool (200) according to the fifth aspect of the present disclosure is, in the third or fourth aspect, the cord-like body (221) has a first end (221a) and a second end (221b), the first end (221a) of the cord-like body (221) is connected to the traction mechanism (230), the second end (221b) of the cord-like body (221) is connected to the connector (212) of the polishing section (210), the traction section (220) has at least one hanger (222) hung on a portion of the cord-like body (221) between the first end (221a) and the second end (221b), and the cord-like body (221) is bent by the hanger (222).

[0068] According to the processing tool (200) of this embodiment, the cord-like body (221) is bent by the hanging device (222), which increases the degree of freedom in arranging the position of the first end (221a) of the cord-like body (221) connected to the traction mechanism (230).

[0069] A processing tool (200) according to a sixth aspect of the present disclosure is the fifth aspect, wherein the hanger (222) is movable.

[0070] According to the processing tool (200) of this embodiment, the hanging device (222) is movable, so that the position of the first end (221a) and / or the second end (221b) of the cord-like body (221) can be adjusted.

[0071] A processing method according to a seventh aspect of the present disclosure is a processing method using the processing tool (200) described in the first aspect, in which the pulling portion (220) pulls the polishing portion (210) in the predetermined direction, causing the polishing portion (210) to rotate around the second axis (L2).

[0072] In the processing method according to an eighth aspect of the present disclosure, in the seventh aspect, the polishing unit (210) is rotated from the side opposite to the side being pulled by the pulling unit (220).

[0073] DESCRIPTION OF SYMBOLS 100 Steam valve 110 First casing 111 First valve chamber 112 Communication flow path 112a Valve seat (inner peripheral surface) 113 Steam inlet 114 Opening 115 Flange surface 120 Second casing 121 Second valve chamber 124 Opening 125 Flange surface 125a Bolt hole 130 Valve portion 131 Valve body 131a Outer peripheral surface 132 Arm 140 Cover (for first casing) 150 Cover (for second casing) 200 Processing tool 210 Grinding portion 211 Grinding portion main body 211a Outer peripheral surface 212 Omnidirectional eyebolt (connector) 212a Bolt portion 212b Ring portion 220 Traction portion 221 Wire 221a First end 221b Second end 222 Pulley (hanging device) 230 Traction mechanism 231 Frame 231a (231a1) Frame shaft 231a (231a2) Frame shaft 231b Fixed plate 231c Fixed plate 232 Base plate 233 Movable plate 233a Ring 234 Push-in portion 234a Push-in shaft 234b Handle 235 Gas spring (first loading means) 235a Tube 235b Rod 236 Spring load application portion (second loading means) 236a Threaded shaft 236b Nut 236c Coil spring L1 First axis (axis of valve seat) L2 Second axis (axis of processing tool (grinding portion))

Claims

1. A processing tool for processing an inner surface having a first axis as a central axis and an inner diameter decreasing in a predetermined direction along the first axis, comprising: a grinding unit; and a pulling unit, wherein the grinding unit has an outer peripheral surface having a second axis as a central axis and conforming to the shape of the inner peripheral surface, the outer peripheral surface including a grinding surface for grinding the inner peripheral surface, and the pulling unit is configured to pull a center position of the grinding unit in the predetermined direction with the outer peripheral surface of the grinding unit facing the inner peripheral surface.

2. The processing tool according to claim 1, wherein the polishing unit has a polishing unit main body including the outer peripheral surface, and a connecting device provided on the polishing unit main body and to which the towing unit is connected, the connecting device connecting the polishing unit main body to the towing unit so as to be freely rotatable around the second axis.

3. The processing tool according to claim 2, wherein the towing section has: a cord-like body connected to the connecting tool and transmitting a towing force to the polishing body; and a towing mechanism that imparts a force to the cord-like body to tow the polishing body.

4. The processing tool according to claim 3, wherein the traction mechanism has: a first loading means for applying a force to the cord-like body to pull the polishing unit body in the specified direction; and a second loading means for applying a force to the cord-like body to release the tension generated in the cord-like body by the first loading means.

5. The processing tool described in claim 3 or 4, wherein the rope-like body has a first end and a second end, the first end of the rope-like body is connected to the traction mechanism, the second end of the rope-like body is connected to the connector of the polishing section, the traction section has at least one hanging device hung on a portion of the rope-like body between the first end and the second end, and the rope-like body is bent by the hanging device.

6. The processing tool according to claim 5, wherein the hanging tool is movable.

7. A processing method using the processing tool according to claim 1, comprising the steps of: pulling the grinding part in the predetermined direction with the pulling part; and rotating the grinding part around the second axis.

8. The processing method according to claim 7, wherein the polishing part is rotated from the side opposite to the side being pulled by the pulling part.

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