Mounting structure for mounting valve plate to valve rod in gate valve, and gate valve having mounting structure

Abstract

(Problem) By precisely and securely fixing the valve plate to the valve rod, the generation of particles during gate valve operation is prevented. (Solution) A spacer member (30) having a wedge-shaped flat plate (36) and a coupling protrusion (37) is interposed between the end wall surface (13d) of the attachment hole (13) of the valve plate (3) and the rod front surface (15) of the attachment part (14) of the valve rod (4), thereby forming a wedge-shaped gap (G2) that opens forward between the spacer member and the end wall surface of the hole, and a moment (M) is generated to deform the valve plate in a direction that constricts the gap (G2) by the fastening force of the valve plate fixing screw (20), and the coupling protrusion of the spacer member is pressed into the wedge-shaped gap formed between the inclined surface (15b) of the rod front surface and the rear wall surface (13b) of the attachment hole, thereby pressing the front wall surface (13a) of the attachment hole of the valve plate against the front wall surface (14a) of the attachment part of the valve rod.

Description

Technology Field

[0001] The present invention relates to an attachment structure for attaching a valve plate of a gate valve to the tip of a valve rod, and a gate valve having such an attachment structure for the valve plate. Background Technology

[0002] In a semiconductor processing apparatus, a gate valve is used to open and close an opening leading to a vacuum chamber. This gate valve is configured to accommodate a valve plate attached to the tip of a valve rod within a valve box, and to attach this valve box to a vacuum chamber so that the opening formed in the side wall of the valve box is opened and closed by the valve plate. At that time, the closing of the opening is achieved by pressing a seal member attached to the valve plate against a valve seat surrounding the opening.

[0003] For example, the gate valve of Patent Document 1 is designed to improve maintainability by making the upper wall of the valve box detachable and by fixing the valve plate axially to the upper end of the valve rod with a screw, thereby allowing the valve plate to be detached from the valve rod by operation from the outside of the valve box. In addition, in this gate valve, the valve plate is attached to the valve rod so as to be rotatable about the axis, so that when the valve plate is pressed against the valve seat, the valve plate rotates along the valve seat, thereby allowing the seal surface (seal member) of the valve plate to be pressed uniformly against the valve seat.

[0004] However, with the recent miniaturization and performance of semiconductors, the miniaturization of semiconductor linewidths has been progressing, and as a result, there is a strong demand to reduce the particles generated during the semiconductor processing process so that they approach zero.

[0005] However, the gate valve disclosed in the above patent document 1 has a problem in that particles are likely to be generated due to friction between the valve rod and the valve plate or between the valve plate and the valve seat when the valve is operated. Therefore, in order to prevent such particles from being generated, it is indispensable to fix the valve plate to the valve rod with high precision and securely. Prior art literature

[0006] Japanese Patent Publication No. 2005-291221

[0007] The technical problem of the present invention is to prevent the generation of particles during gate valve operation by fixing the valve plate to the valve rod with high precision and stability.

[0008] To solve the above problem, the present invention relates to a gate valve configured to accommodate a valve plate attached to the tip of a valve rod extending in the vertical direction within a valve box, and to open and close a gate opening formed on the side wall of the valve box by the valve plate, wherein the valve plate has a valve front surface attached with a seal member attached to a valve seat around the gate opening, a valve rear surface located opposite the valve front surface, a valve upper surface and a valve lower surface, an attachment hole opened on the valve lower surface for inserting an attachment portion of the tip of the valve rod, and a screw insertion hole formed through the valve upper surface and the attachment hole for inserting and passing a valve plate fixing screw, and is attached to the valve rod by the valve plate fixing screw, wherein the attachment hole has a hole front wall located on the valve front surface side, a hole rear wall located on the valve rear surface side, and a hole end wall that is the end surface in the depth direction of the attachment hole, and the screw insertion hole is opened on the hole end wall, and the valve The attachment portion of the rod has a rod front wall surface facing the front wall surface of the attachment hole, a rod rear wall surface facing the rear wall surface of the attachment hole, and a rod front end surface located at the tip of the attachment portion, and a screw hole is opened in the rod front end surface to fasten by screwing a valve plate fixing screw inserted through the screw insertion through hole of the valve plate, and when the attachment portion of the valve rod is inserted into the attachment hole of the valve plate up to the end where the rod front end surface contacts and the valve plate fixing screw is not screwed into the screw hole, a horizontal gap is formed in the portion fitted by the end wall surface of the attachment hole and the rod front end surface of the valve rod, which is open toward the rod front wall surface of the attachment portion and closed toward the rod rear wall surface side relative to the center axis of the screw hole.

[0009] A spacer member is installed between the end wall of the attachment hole and the front end surface of the rod of the attachment part, and the spacer member has an upper surface that contacts the end wall of the hole, a lower surface that contacts the front end surface of the rod, and a through hole formed between the upper and lower surfaces to allow the valve plate fixing screw to be inserted and passed through. A gap is formed between the upper surface of the spacer member and the end wall of the attachment hole, and the gap is opened toward the front wall of the rod of the attachment part and is closed by contact between the upper surface of the spacer member and the end wall of the attachment hole at the rear wall of the rod side relative to the through hole. By doing so, the valve plate fixing screw is screwed into the screw hole and fastened, thereby causing the front wall of the hole of the valve plate to be pressed against the front wall of the rod of the valve rod.

[0010] In the present invention, preferably, the gap is formed in a wedge shape in which the opening width in the vertical direction gradually decreases from the front wall side of the rod towards the rear wall side of the rod.

[0011] In this case, preferably, the upper and lower surfaces of the spacer member are formed by flat surfaces, and the spacer member has a flat plate portion formed by these upper and lower surfaces, a front edge on the front wall side of the rod, and a rear edge on the rear wall side of the rod, and the flat plate portion is formed in a wedge shape such that the thickness between the upper surface and the lower surface gradually increases from the front edge to the rear edge side, and thereby the gap is formed in a wedge shape such that the gap gradually decreases from the front edge to the rear edge side.

[0012] And, more preferably, the spacer member also has a coupling protrusion formed protruding downward at its rear end, wherein the coupling protrusion is formed in a wedge shape such that its width in the front-rear direction gradually narrows toward the lower front end by means of a first surface installed upright downward from the rear end edge and a second surface installed upright downward from the rear edge of the lower surface, and the rod front end surface of the attachment part is formed by a flat surface portion extending perpendicular to the central axis from the front edge side to the rear edge side and an inclined surface portion inclined such that the width in the front-rear direction of the attachment part gradually widens from the rear edge of the flat surface portion toward the base side of the attachment part, and wherein, when the valve plate is fixedly attached to the attachment part of the valve rod by screwing the valve plate fixing screw into the screw hole, the coupling protrusion of the spacer member is pressed between the rear wall surface of the attachment hole and the inclined surface portion of the rod front end surface, thereby causing the first surface of the coupling protrusion to be pressed against the rear wall surface of the hole In addition to being press-fitted, the second surface of the coupling protrusion is press-fitted to the inclined surface. Here, more preferably, in the spacer member, the first surface of the coupling protrusion forms an acute angle with the upper surface of the flat plate and a right angle with the lower surface of the flat plate.

[0013] In addition, in the above embodiment of the present invention, more preferably, the valve plate fixing screw has a screw body portion that is screw-coupled to the screw hole and a screw head portion for operation that is integrally connected to the base of the screw body portion, and the screw body portion has a male screw portion with screw threads formed on its outer circumference and a cylindrical shaft portion installed adjacent to the base side than the male screw portion, and the screw hole has a female screw portion with screw threads formed on its inner circumference for screw-coupled to the male screw portion and a cylindrical portion with a circular cross-section installed adjacent to the rod end surface side than the female screw portion, and a screw thread capable of screw-coupled to the male screw portion of the valve plate fixing screw is formed on the inner circumference of the through hole of the spacer member, and the length of the male screw portion of the valve plate fixing screw in the direction of the central axis is formed to be shorter than the length of the cylindrical portion of the screw hole.

[0014] In addition, according to the present invention, a gate valve configured to accommodate a valve plate attached to the tip of a valve rod extending in the vertical direction within a valve box and to open and close a gate opening formed on the side wall of the valve box by the valve plate, wherein the valve plate is attached to the valve rod by the attachment structure.

[0015] (Effect of the invention)

[0016] According to the present invention, the attachment portion of a valve rod is inserted into the attachment hole of a valve plate up to the end where the front end surface of the rod contacts, and the screw body portion of a valve plate fixing screw is not screwed into the screw hole of the front end surface of the rod. In the portion fitted by the end wall of the attachment hole and the upper surface of a spacer member, a horizontal gap is formed that is open toward the front wall surface of the rod of the attachment portion and is closed toward the rear wall surface of the rod relative to the center axis of the screw hole.

[0017] Therefore, when the valve plate is fixedly attached (fastened) to the attachment portion of the valve rod by screwing the valve plate fixing screw into the screw hole, the fastening force resulting from the fastening acts on the valve plate to narrow the gap, and the front wall surface of the hole of the valve plate is pressed against the front wall surface of the valve rod by the moment caused by the fastening force. Accordingly, the valve plate can be fixed to the valve rod with high precision and rigidity, thereby preventing the generation of particles caused by friction between the valve plate and the valve rod. Brief explanation of the drawing

[0018] FIG. 1 is a front view of a gate valve to which the present invention is applied. Figure 2 is a magnified cross-sectional view along the line A-A' of Figure 1. Figure 3 is a front view of the valve plate. Figure 4 is a magnified cross-sectional view along the line B-B' of Figure 3. FIG. 5 is a cross-sectional view showing the valve plate, valve rod, valve plate fixing screw, and spacer member separated. Figure 6 is a perspective view of the attachment portion of the valve rod. FIG. 7 is a drawing showing the shape of a spacer member, (a) is a perspective view, (b) is a plan view, (c) is a cross-sectional view along the line C-C' of (b), (d) is a front view, and (e) is a rear view. Figure 8 is a partial enlarged cross-sectional view showing the state before the valve plate is fixed to the valve rod. FIG. 9 is a partial cross-sectional view showing the valve plate fixed to the valve rod. FIG. 10 is a perspective view of a gate valve in a state where the valve plate has been moved to the evacuation position. FIG. 11 is a perspective view of a gate valve with the cover on the upper surface of the valve box removed. FIG. 12 is a perspective view of a gate valve when the valve plate fixing screw connecting the valve plate and the valve rod is loosened. FIG. 13 is a perspective view of a gate valve with the valve plate removed from the valve box. FIG. 14 is a partial enlarged cross-sectional view showing the state when the valve plate is detached from the valve rod. Specific details for implementing the invention

[0019] FIGS. 1 and 2 show an embodiment of a gate valve in which the attachment structure according to the present invention is applied to the attachment of a valve plate (3) to a valve rod (4). This gate valve is used by attaching it to an opening of a vacuum chamber not shown, and has a valve box (1) having a gate opening (2) that leads to the opening of the vacuum chamber, a valve plate (3) that is housed inside the valve box (1) and opens and closes the gate opening (2), a valve rod (4) for opening and closing operation that has an axis (L1) and is fixed to the valve plate (3), and a valve driving unit (5) that drives the valve rod (4).

[0020] And, by driving the valve rod (4) by the valve driving unit (5), the valve plate (3) is configured to reciprocate between the closed position of the solid line, which is the position where the gate opening (2) is closed as shown in FIG. 2, and the open position (evacuation position) of the two-dot dashed line, which is the position where the gate opening (2) is opened. In addition, the valve driving unit (5) is equipped with a driving mechanism consisting of an air cylinder or a cam mechanism, but since the various structures and operations of such a valve driving unit (5) are already well known, a description thereof will be omitted here.

[0021] The above valve box (1) is formed as a hollow box shape with a horizontally elongated rectangular prism exterior, and among the front and rear side walls (1a, 1c) of the valve box (1), the front side wall (1a) connected to the vacuum chamber has a horizontally elongated rectangular gate opening (2) and a flat valve seat (1b) that surrounds the gate opening (2) in a ring shape. In addition, at the closed position, the gate opening (2) is closed by the seal member (7) attached to the front surface of the valve plate (3) being pressed against the valve seat (1b) by the valve driving unit (5).

[0022] As is evident from FIGS. 10 and 11, a cover (10) is detachably attached to the upper surface of the valve box (1) by means of a plurality of cover attachment screws (11), and the upper surface of the valve box (1) can be opened by removing the cover (10). Also, as is evident from FIGS. 12 and 13, the valve plate (3) can be removed from the valve rod (4) through the opening (12) of the opened upper surface and taken out to the outside of the valve box (1).

[0023] Additionally, as shown in FIG. 2, a second gate opening (1d) is formed in the rear side wall (1c) of the valve box (1), but this gate opening (1d) forms a passage within the valve box (1) for moving a workpiece, etc. into and out of the vacuum chamber together with the first gate opening (2) which is opened when the valve plate (3) is in the evacuation position, and is not directly opened or closed by the valve plate (3).

[0024] The above valve plate (3) is integrally formed from aluminum and, as is evident from FIGS. 2-5, has a horizontally slender and long rectangular plate shape and has a valve front surface (3a) to which the seal member (7) is attached, a valve back surface (3b) opposite to the valve front surface (3a), a valve upper surface (3c) and a valve lower surface (3d), and an attachment hole (13) opened in the valve lower surface (3d). At this time, the valve front surface (3a), valve back surface (3b), valve upper surface (3c) and valve lower surface (3d) are all formed by flat surfaces.

[0025] The attachment hole (13) is a hole for inserting and fixing the attachment portion (14) of the tip (top in the drawing) of the valve rod (4) in the direction of the axis (L1), and the cross-sectional shape of the attachment hole (13) is a long, narrow slot shape in the length direction (left and right direction in the drawing) of the valve plate (3). In addition, the attachment hole (13) has a front wall surface (13a) of the hole located on the front side (3a) of the valve, a rear wall surface (13b) of the hole located on the back side (3b) of the valve, left and right side walls of the hole (13c, 13c), and a hole end wall surface (13d) which is the end in the depth direction of the attachment hole (13).

[0026] Here, the front wall surface (13a) and the rear wall surface (13b) of the hole are flat surfaces parallel to each other, and the side walls (13c, 13c) of the hole are also flat surfaces parallel to each other, and the end wall surface (13d) of the hole is a flat surface perpendicular to the front wall surface (13a), the rear wall surface (13b), and the side walls (13c, 13c). Also, the distance from the front wall surface (13a) of the hole to the front surface (3a) of the valve is formed to be greater than the distance from the rear wall surface (13b) of the hole to the back surface (3b) of the valve. Additionally, as shown in FIG. 4, grooves (S, S) extending in the direction of the axis (L1) are formed at both ends of the front wall surface (13a) of the hole, but since these grooves (S, S) are formed during the cutting process of the attachment hole (13) on the valve plate (3), the description is omitted here.

[0027] Meanwhile, the valve rod (4) is made of stainless steel and, as is evident from FIGS. 2-6, has an attachment part (14) at the tip of a cylindrical main body part (4a) for insertion into the attachment hole (13). The attachment part (14) is shaped such that the side of the cylinder is cut into two parallel flat surfaces along the axis (L1) of the valve rod (4). That is, the valve rod (4) has a rod front wall surface (14a) that contacts the front wall surface (13a) of the attachment hole (13), a rod rear wall surface (14b) that contacts the rear wall surface (13b) of the attachment hole (13), left and right side wall surfaces (14c, 14c) that contact the left and right side wall surfaces (13c, 13c) of the attachment hole (13), and a rod front surface (15) that forms the front surface of the attachment part (14) in the direction of the axis (L1) (i.e., the front surface of the valve rod (4).

[0028] The front wall surface (14a) and the rear wall surface (14b) of the rod are flat surfaces parallel to each other along the axis (L1), and the side wall surfaces (14c, 14c) of the rod are convex curved surfaces forming an arc shape on the outside. Additionally, the front end surface (15) of the rod is formed by a flat surface portion (15a) extending from the front edge connected to the front wall surface (14a) of the rod toward the rear wall surface (14b), and an inclined surface portion (15b) that slopes from the rear edge of the flat surface portion (15a) toward the base portion (14d) of the attachment portion (14) so ​​that the width of the attachment portion (14) in the front-rear direction gradually expands.

[0029] And, the flat surface portion (15a) extends in a horizontal direction perpendicular to the axis line (L1) and the central axis (L2) described later, and the inclined surface portion (15b) is formed on the flat surface and its rear edge is connected to the rod rear wall surface (14b). The angle formed by the flat surface portion (15a) and the inclined surface portion (15b) is not particularly limited as long as it is an obtuse angle, but is preferably about 120°.

[0030] Here, the distance (W1) between the front wall surface (13a) and the rear wall surface (13b) of the attachment hole (13) is formed to be slightly larger than the distance (W2) between the front wall surface (14a) and the rear wall surface (14b) of the rod in the attachment part (14). And, as described above, when the valve plate (3) is attached to the valve rod (4), the front wall surface (14a) of the rod in the attachment part (14) is made to come into contact with the front wall surface (13a) of the attachment hole (13). Therefore, when the valve plate (3) is attached to the valve rod (4), a gap (G1) of W1-W2 is formed between the rear wall surface (14b) of the rod and the rear wall surface (13b) (Figs. 2, 8, and 9). In addition, the length in the direction of the axis (L1) of the attachment part (14) is formed to be greater than the depth of the attachment hole (13), that is, the distance from the lower surface of the valve (3d) to the end wall of the hole (13d).

[0031] However, as shown in FIGS. 5-14, the valve plate (3) is attached to the tip of the valve rod (4) so ​​as to be detachably attached in the direction of the axis (L1) of the valve rod (4) by means of a valve plate fixing screw (20). For this attachment, a screw insertion hole (16) for inserting and passing the valve plate fixing screw (20) is formed on the valve upper surface (3c) of the valve plate (3) on a central axis (L2) parallel to the axis (L1), and a screw hole (17) for screwing and fastening (screw fixing) the valve plate fixing screw (20) is formed on the central axis (L2) on the rod tip surface (15) of the valve rod (4). In addition, in this embodiment, when the valve plate (3) is attached to the valve rod (4), a plate-shaped spacer member (30) is clamped between the end wall surface (13d) of the attachment hole (13) and the end surface (15) of the rod of the attachment part (14).

[0032] Additionally, when the valve plate (3) is attached to the valve rod (4), the central axis (L2) is located further back (towards the rear wall surface (14b) of the rod) than the axis line (L1) of the valve rod (4), and further back (towards the rear wall surface (3b) of the valve plate (3) than the center between the front surface (3a) of the valve and the rear surface (3b) of the valve plate (3). Furthermore, the central axis (L2) is located further forward (towards the front wall surface (13a) of the hole) than the center between the front wall surface (13a) of the hole and the rear wall surface (13b) of the attachment hole (13), and further forward (towards the front wall surface (14a) of the rod) than the center between the front wall surface (14a) of the rod and the rear wall surface (14b) of the attachment part (14).

[0033] In addition, the distance between the central axis (L2) and the front wall surface (13a) of the hole is equal to the distance between the central axis (L2) and the front wall surface (14a) of the rod. By doing so, when the valve plate fixing screw (20) is screwed into the screw hole (17) of the valve rod (4) through the screw insertion through hole (16) of the valve plate (3), the attachment part (14) is positioned so that the front wall surface (14a) of the rod is in contact with the front wall surface (13a) of the hole within the attachment hole (13). Furthermore, the central axis (L2) is located in the center between a pair of hole side walls (13c, 13c) in the attachment hole (13) in the left-right direction, and is located in the center between a pair of rod side walls (14c, 14c) in the attachment part (14).

[0034] The above valve plate fixing screw (20) is formed by a screw body part (21) having a male screw and a screw head part (22) for operation connected to the base of the screw body part. The screw body part (21) has a male screw part (21a) on the tip side having screw threads formed on the outer surface, and a cylindrical shaft part (21b) (without screw threads formed on the outer surface) installed on the base side of the male screw part (21a) and adjacent to the male screw part (21a), and the base of the shaft part (21b) is integrally connected to the lower surface of the screw head part (22). In addition, a hexagonal hole (22a) for operation is opened on the upper surface of the screw head part (22) to insert and operate a hexagonal wrench (25a).

[0035] Additionally, an air hole (23) is formed through the bottom surface of the hexagonal hole (22a) for operation and the front surface of the screw body (21), and when the valve plate fixing screw (20) is screwed into the screw hole (17), the air inside the screw hole (17) can be discharged to the outside through the air hole (23).

[0036] Here, the outer diameter of the screw head portion (22) is formed to be larger than the outer diameter (d1) of the male screw portion (21a) (the diameter of the cylinder connecting the tips of the screw threads) and the diameter (d2) of the shaft portion (21b), and the outer diameter (d1) of the male screw portion (21a) is formed to be larger than the diameter (d2) of the shaft portion (21b). Additionally, in the direction of the central axis (L2), the length (S1) of the male screw portion (21a) is formed to be shorter than the length (S2) of the shaft portion (21b).

[0037] The screw insertion passage hole (16) of the valve plate (3) is formed through the valve upper surface (3c) of the valve plate (3) and the hole end wall surface (13d) of the attachment hole (13), and has a large diameter portion (16a) that is open to the valve upper surface (3c) and receives the screw head portion (22) of the valve plate fixing screw (20), and a small diameter portion (16b) through which the screw body portion (21) (i.e., male screw portion (21a) and shaft portion (21b)) of the valve plate fixing screw (20) is inserted and passes between the bottom surface of the large diameter portion (16a) and the hole end wall surface (13d). By this, an annular flange portion (18) is formed between the bottom surface of the large diameter portion (16a) and the hole end wall surface (13d).

[0038] The inner diameter and depth of the large diameter portion (16a) are formed to a size such that the screw head portion (22) fits completely with the anti-loosening washer (29), and the inner diameter (d3) of the small diameter portion (16b) is smaller than the inner diameter of the large diameter portion (16a) or the outer diameter of the screw head portion (22), but larger than the outer diameter (d1) of the male screw portion (21a) and the diameter (d2) of the shaft portion (21b) of the valve plate fixing screw (20). Additionally, the inner diameter of the large diameter portion (16a) is formed to be slightly smaller than the distance (W1) between the front wall surface (13a) and the rear wall surface (13b) of the hole, or the distance (W2) between the front wall surface (14a) and the rear wall surface (14b) of the rod.

[0039] The above screw hole (17) has a female screw portion (17a) that has a screw thread formed on its inner surface to screw-couple the male screw portion (21a) of the valve plate fixing screw (20), and a cylindrical portion (17b) in which the cross-sectional shape is formed as a circle of diameter (d4) (i.e., no screw thread formed on its inner surface). The cylindrical portion (17b) is opened on the flat surface portion (15a) of the rod end surface (15) and is formed from the flat surface portion (15a) to a position of length (depth) (S3) along the central axis (L2). Additionally, the cylindrical portion (17b) is formed closer to the rod end surface (15) than the female screw portion (17a) and adjacent to the female screw portion (17a).

[0040] Here, the length of the cylindrical portion (17b) (i.e., the distance from the flat surface portion (15a) of the rod end surface (15) to the tip of the female screw portion (17a)) (S3) is formed to be equal to or greater than the length (S1) of the male screw portion (21a) of the valve plate fixing screw (20). In addition, the length in the direction of the central axis (L2) of the female screw portion (17a) is formed to be larger than the length (S1) of the male screw portion (21a), and when fastening (i.e., fixing) the valve plate (3) to the attachment portion (14) of the valve rod (4), the male screw portion (21a) of the valve plate fixing screw (20) is screwed into the female screw portion (17a) of the screw hole (17) so that the entire male screw portion (21a) is screwed into the female screw portion (17a).

[0041] The above spacer member (30) is integrally formed by stainless steel and, as shown in FIGS. 5-9, has a front edge (31) positioned on the front wall surface (14a) of the rod and a rear edge (32) positioned on the rear wall surface (14b) of the rod, and a pair of side cross-sections (33, 33) positioned on the side wall surfaces (14c, 14c) of the rod, and is formed as a long rectangle in the left-right direction (direction along the front edge (31) and rear edge (32)) when viewed in a plane. That is, the front edge (31) and the rear edge (32) are parallel to each other, and the pair of side faces (33, 33) are also parallel to each other, and the pair of side faces (33, 33) placed at both ends of the front edge (31) and the rear edge (32) are perpendicular to each other with respect to the front edge (31) and the rear edge (32).

[0042] Additionally, the spacer member (30) has an upper surface (34) that contacts the end wall surface (13d) of the hole and a lower surface (35) that contacts the front end surface (15) of the rod. These upper surface (34) and lower surface (35) are formed by flat surfaces. Furthermore, a through hole (36a) is formed between these upper surface (34) and lower surface (35), which is positioned on the central axis (L2) and allows the screw body (21) of the valve plate fixing screw (20) to be inserted and passed through. In addition, the spacer member (30) has a flat plate portion (36) formed by these upper surface (34) and lower surface (35) at its front end, which includes the front edge (31), and a connecting protrusion (37) formed protruding downward at the rear end of the spacer member (30), which includes the rear edge (32), as the rear end of the flat plate portion (36).

[0043] The lower surface (35) is perpendicular to the central axis (L2) and extends from the front edge (31) toward the rear edge (32) rather than the through hole (36a). Meanwhile, the upper surface (34) is slightly inclined (preferably about 3°) so that the distance from the lower surface (35) gradually increases from the front edge (31) toward the rear edge (32), and extends from the front edge (31) toward the rear edge (32) rather than the central axis (L2) (preferably toward the rear edge (32) rather than the through hole (36a) as in this embodiment). That is, the flat plate (36) is formed in a wedge shape such that its thickness in the direction of the central axis (L2) gradually increases from the front edge (31) toward the rear edge (32).

[0044] For this reason, as shown in FIG. 8, when the attachment portion (14) of the valve rod (4) is inserted into the attachment hole (13) of the valve plate (3) up to the end where the rod end surface (15) contacts, and the valve plate fixing screw (20) is not screwed into the screw hole (17), a horizontal gap (G2) is formed in the direction of the central axis (L2) in the part fitted by the hole end wall surface (13d) and the rod end surface (15) (preferably between the hole end wall surface (13d) and the upper surface (34) of the spacer member (30) as in the present embodiment). At this time, the gap (G2) is formed in a wedge shape that is open toward the front wall surface (14a) of the rod and closed toward the rear wall surface (14b) of the rod rather than the central axis (L2) (preferably, as in this embodiment, the through hole (36a) of the spacer member (30)).

[0045] And, in fixing (fastening) the valve plate (3) to the attachment part (14) of the valve rod (4), as shown in FIG. 9, when the valve plate fixing screw (20) is fastened by screwing it into the screw hole (17) of the attachment part (14), the fastening force resulting from the fastening acts on the flange part (18) of the valve plate (3) to constrict the gap (G2), and the front wall surface (13a) of the hole of the valve plate (3) is pressed against the front wall surface (14a) of the valve rod (4) by the moment (M) generated by the fastening force.

[0046] In addition, in this embodiment, a thread is formed on the inner circumference of the through hole (36a) such that the male thread portion (21a) of the valve plate fixing screw (20) can be screwed into the through hole (36a) to pass through the through hole (36a). Furthermore, the inner diameter of the through hole (36a) (i.e., the diameter of the cylinder connecting the tips of the threads) (d5) is smaller than the outer diameter (d1) of the male thread portion (21a) and slightly larger than the diameter (d2) of the shaft portion (21b). By doing so, as shown in FIG. 14, when the valve plate fixing screw (20) is loosened to detach the valve plate (3) from the valve rod (4), the spacer member (30) remains on the shaft portion (21b) without being removed from the screw body portion (21) of the valve plate fixing screw (20).

[0047] Meanwhile, as shown in FIG. 7, the coupling protrusion (37) is formed by a first surface (37a) installed vertically downward from the rear edge (32) and a second surface (37b) installed obliquely downward from the rear edge of the lower surface (35). The first surface (37a) of the coupling protrusion (37) is in contact with the rear wall surface (13b) of the attachment hole (13), and the second surface (37b) is in contact with the inclined surface (15b) of the rod end surface (15).

[0048] That is, the coupling protrusion (37) is positioned near the rear edge (32) of the through hole (36a) and is formed in a wedge shape such that the width in the front-rear direction (distance between the first surface (37a) and the second surface (37b)) gradually narrows toward the lower front end. Furthermore, when the valve plate fixing screw (20) is fastened to the screw hole (17), the coupling protrusion (37) is pressed into the wedge-shaped gap formed between the inclined surface (15b) and the rear wall surface (13b) of the hole, thereby causing the first surface (37a) to be pressed against the rear wall surface (13b) of the hole and the second surface (37b) to be pressed against the inclined surface (15b).

[0049] Here, the first surface (37a) is formed as a flat surface that is perpendicular to the lower surface (35) (i.e. parallel to the central axis (L2)) and forms an acute angle (preferably about 87°) slightly smaller than a right angle with the upper surface (34). Additionally, the second surface (37b) has a flat surface that forms an obtuse angle with the lower surface (35), and the angle is preferably about 120° and is equal to the angle formed by the flat surface portion (15a) and the inclined surface portion (15b) in the rod end surface (15). In addition, the distance from the center (center axis (L2)) of the through hole (36a) to the first surface (37a), that is, the rear edge (32), is formed to be equal to the distance from the center axis (L2) to the rear wall surface (13b) of the hole when the front wall surface (14a) of the rod is in contact with the front wall surface (13a) of the hole.

[0050] Next, a method for attaching and detaching the valve plate (3) to the valve rod (4) in a gate valve having the configuration described above with reference to FIGS. 8-14 will be explained.

[0051] First, in the assembly process of initially attaching the valve plate (3) to the valve rod (4), as shown in FIG. 8, the spacer member (30) is inserted into the attachment hole (13) from the valve bottom surface (3d) of the valve plate (3) so that its front edge (31) faces the front wall surface (13a) of the attachment hole (13), its rear edge (32) faces the rear wall surface (13b) of the attachment hole, and a pair of side surfaces (33, 33) face the side walls (13c, 13c) of the attachment hole, and is moved to the end that contacts the end wall surface (13d) of the attachment hole.

[0052] In addition, at the same time, the attachment portion (14) of the valve rod (4) is inserted from the lower surface (3d) of the valve into the attachment hole (13) until the end portion where the rod's front end surface (15) contacts the spacer member (30) within the attachment hole (13). In this state, as described above, since the upper surface (34) of the spacer member (30) is inclined with respect to its lower surface (35), a wedge-shaped gap (G2) is formed between the upper surface (34) and the end wall surface (13d), which is open toward the front wall surface (14a) of the rod and closed by the contact between the upper surface (34) and the end wall surface (13d) of the rod at the rear wall surface (14b) side rather than the central axis (L2) (preferably the through hole (36a)).

[0053] Next, the screw body portion (21) of the valve plate fixing screw (20) is inserted into the screw insertion through hole (16) from the valve upper surface (3c) of the valve plate (3), and the tip of the male screw portion (21a) of the screw body portion (21) is inserted until it reaches the through hole (36a) of the spacer member (30). Then, the male screw portion (21a) is screwed into the threads of the through hole (36a), and the screw coupling is continued until the entire male screw portion (21a) passes through the through hole (36a), at which point the entire male screw portion (21a) is received within the cylindrical portion (17b) of the screw hole (17). As shown in FIG. 9, the male screw portion (21a) is screwed into the female screw portion (17a) of the screw hole (17), and when tightened with a predetermined torque, the compressive force from the screw head portion (22) acts on the flange portion (18) through the washer (29), and thereby the valve plate (3) is fastened to the attachment portion (14) of the valve rod (4).

[0054] At that time, as a result of the fastening force by the fastening of the valve plate fixing screw (20), that is, the compressive force by the screw head (22), acting on the flange portion (18) of the valve plate (3) to constrict the gap (G2), the closed position of the gap (G2) in the front and rear direction (i.e., the pressure position of the hole end wall surface (13d) relative to the upper surface (34) of the spacer member (30)) is located on the rod rear wall surface (14b) side rather than the central axis (L2) (preferably the through hole (36a)), so as shown in FIG. 9, a left-turning moment (M) acts on the valve plate (3) with the rear side centered on the central axis (L2) (preferably the through hole (36a)). And, by that moment (M), the valve plate (3) is slightly deformed to constrict the gap (G2), and as a result, the hole front wall (13a) in contact with the rod front wall (14a) is pressed against the rod front wall (14a).

[0055] At the same time, the lower surface (35) of the spacer member (30) is pressed against the flat surface (15a) of the rod end surface (15) by the fastening force of the valve plate fixing screw (20), and the coupling protrusion (37) of the spacer member (30) is pressed into the wedge-shaped gap formed between the inclined surface (15b) of the rod end surface (15) and the rear wall surface (13b) of the attachment hole (13). By this, the first surface (37a) of the spacer member (30) is pressed against the rear wall surface (13b) of the hole, and the second surface (37b) is pressed against the inclined surface (15b), and as a result, a rearward pressing force (F) is applied to the valve plate (3), so that the front wall surface (13a) of the hole of the valve plate (3) is further pressed against the front wall surface (14a) of the valve rod (4).

[0056] According to this embodiment, the valve plate (3) can be fixed to the valve rod (4) with high precision and strength by utilizing a very simple structure in which the spacer member (30) is interposed between the rod end surface (15) of the valve rod (4) and the hole end wall surface (13d) of the valve plate (3), and furthermore, by a very simple operation in which the valve plate fixing screw (20) is screwed into the screw hole (17) of the valve rod (4) through the screw insertion through hole (16) of the valve plate (3), the valve plate (3) can be fixed to the valve rod (4) with high precision and strength, and as a result, the generation of particles due to friction between the valve plate (3) and the valve rod (4) during gate valve operation can be prevented.

[0057] Meanwhile, in order to remove the valve plate (3) from the valve rod (4) and take it out of the valve box (1) for maintenance such as replacing the seal member (7) of the valve plate (3), as shown in FIG. 10, first, the valve driving unit (5) is operated to move the valve plate (3) from the rising position (blocked position) indicated by the solid line in FIG. 2 to the lowering position (evacuation position) indicated by the two-dot dashed line in FIG. 2.

[0058] Next, as shown in FIG. 11, the cover (10) is removed by removing the cover attachment screw (11) on the upper surface of the valve box (1), and the window hole (12) on the upper surface of the valve box (1) is opened.

[0059] As shown in FIG. 12, a hexagonal wrench (25a) is inserted through the window opening (12) to loosen the valve plate fixing screw (20), and the screw connection between the male screw portion (21a) and the female screw portion (17a) within the screw hole (17) of the valve rod (4) is completely released, and the entire male screw portion (21a) is received within the cylindrical portion (17b).

[0060] Next, as shown in FIG. 13, two gripping tools (25b, 25b) with male threads are screwed into two tool mounting holes (26, 26) with female threads, and then the valve plate (3) is pulled up by holding these two gripping tools (25b, 25b) in both hands. Then, the valve plate (3) is separated from the valve rod (4), and the valve plate (3) can be pulled out to the outside through the window hole (12) on the upper surface of the valve box (1).

[0061] At this time, as described above, a thread is formed on the inner surface of the through hole (36a) of the spacer member (30) to be screw-coupled with the male thread portion (21a) of the valve plate fixing screw (20), and the inner diameter (d5) of the through hole (36a) is formed to be smaller than the outer diameter (d1) of the male thread portion (21a). Therefore, as shown in FIG. 14, the valve plate (3) can be separated from the valve rod (4) and taken out of the valve box (1) without removing the spacer member (30) from the screw body portion (21) of the valve plate fixing screw (20) and the attachment hole (13) of the valve plate (3).

[0062] After maintenance is completed, the valve plate (3) is reattached to the two gripping tools (25b, 25b) in the two tool mounting holes (26, 26), and the two gripping tools (25b, 25b) are held in the hand and housed inside the valve box (1). Then, after inserting the attachment part (14) of the valve rod (4) into the attachment hole (13) of the valve plate (3), the gripping tools (25b, 25b) are removed, and the valve plate fixing screw (20) is screwed into the screw hole (17) using the hex wrench (25a) to fix the valve plate (3) to the valve rod (4). Finally, by attaching the cover (10) to the upper surface of the valve box (1) with the cover attachment screw (11), the gate valve becomes usable again as shown in FIG. 10.

[0063] Although the attachment structure of a valve plate to a valve rod in a gate valve according to the present invention and an embodiment of a gate valve having the attachment structure have been described in detail above, in this embodiment, for example, in forming the gap (G2), it is not necessary to install a spacer member (30) having the shape above between the rod end surface (15) and the hole end wall surface (13d), and the gap (G2) may be formed by forming an inclined surface on the rod end surface (15) itself and the rod end surface (15) and the hole end wall surface (13d). In addition, in this embodiment, the moment (M) and compressive force (F) shown in FIG. 9 are generated by a single spacer member (30), but the moment (M) and compressive force (F) may be generated by individual members. Explanation of the symbols

[0064] 1 valve box 1a side wall 1b valve seat 2 Gate opening 3 valve plate 3a Valve front surface 3b Valve back 3c Valve upper surface 3D If you speak of the valve 4 valve rod 5 Valve actuator 7 absence of time 10 cover 11 Cover attachment screws 12 window hole 13 Attachment hole 13a front wall of the hole 13b Back wall of the hole 13c Hole side wall 13d End wall of the hole 14 Attachment part 14a Road front wall 14b Road rear wall 14c Road side wall 14d base 15 Rod tip 15a flat surface 15b Sloping surface 16 screw insertion through hole 16a Daegyeongbu 16b Blind man 17 screw hole 17a female screw 17b cylindrical part 20 Valve plate fixing screw 21 Screw body 21a Male screw 21b Shrine 22 screw head 30 Spacer absence 31 Shear edge 32 rear edge 33 Side cross-section 34 Top surface 35 underneath 36 reputation department 36a through hole 37 Connecting protrusion 37a Page 1 37b Page 2 W1 Distance between the front wall (13a) and the rear wall (13b) of the hole W2 Distance between the front wall surface (14a) and the rear wall surface (14b) of the rod G1 gap G2 air gap L1 axis L2 central axis d1 outer diameter of the male screw part (21a) d2 Diameter of the shaft (21b) d3 The inner diameter of the small neck (16b) d4 inner diameter of the cylindrical part (17b) d5 inner diameter of the through hole (36a) S1 Length of the male screw part (21a) S2 Length of the shaft (21b) S3 Length of the cylindrical part (17b)

Claims

Claim 1 A structure for attaching a valve plate to a valve rod in a gate valve configured to accommodate a valve plate attached to the tip of a valve rod extending in the vertical direction within a valve box, and to open and close a gate opening formed in the side wall of the valve box by the valve plate, wherein the valve plate has a valve front surface attached with a seal member attached to a valve seat around the gate opening, a valve rear surface located opposite the valve front surface, a valve upper surface and a valve lower surface, an attachment hole opened in the valve lower surface for inserting an attachment portion of the tip of the valve rod, and a screw insertion hole formed through the valve upper surface and the attachment hole for inserting and passing a valve plate fixing screw, and is attached to the valve rod by the valve plate fixing screw, wherein the attachment hole has a hole front wall located on the valve front surface side, a hole rear wall located on the valve rear surface side, and a hole end wall that is the end surface in the depth direction of the attachment hole, and the screw insertion hole is opened in the hole end wall, and the attachment portion of the valve rod is of the attachment hole It has a rod front wall facing the front wall of the hole, a rod rear wall facing the rear wall of the attachment hole, and a rod front end face located at the front end of the attachment part, and a screw hole is opened in the rod front end face to fasten by screwing a valve plate fixing screw inserted through a screw insertion through hole of the valve plate, and when the attachment part of the valve rod is inserted into the attachment hole of the valve plate to the end where the rod front end face contacts and the valve plate fixing screw is not screwed into the screw hole, a horizontal gap is formed in the part fitted by the end wall of the attachment hole and the rod front end face of the valve rod, which is open on the rod front wall side of the attachment part and closed on the rod rear wall side relative to the center axis of the screw hole.A spacer member is installed between the end wall of the attachment hole and the front end surface of the rod of the attachment part, and the spacer member has an upper surface that contacts the end wall of the hole, a lower surface that contacts the front end surface of the rod, and a through hole formed between the upper and lower surfaces to allow the valve plate fixing screw to be inserted and passed through, and a gap is formed between the upper surface of the spacer member and the end wall of the attachment hole, and the gap is opened on the front wall side of the rod of the attachment part and is closed by contact between the upper surface of the spacer member and the end wall of the attachment hole on the rear wall side of the rod relative to the through hole, and thereby the valve plate fixing screw is screwed into the screw hole and fastened so that the front wall of the hole of the valve plate is pressed against the front wall of the rod of the valve rod. This characterizes the attachment structure of a valve plate to a valve rod in a gate valve. Claim 2 A structure for attaching a valve plate to a valve rod in a gate valve, characterized in that, in claim 1, the gap is formed in a wedge shape in which the opening width in the vertical direction gradually decreases from the front wall side of the rod toward the rear wall side of the rod. Claim 3 A structure for attaching a valve plate to a valve rod in a gate valve, characterized in that, in claim 1, the upper and lower surfaces of the spacer member are formed by flat surfaces, the spacer member has a flat plate portion formed by the upper and lower surfaces, a front edge on the front wall side of the rod, and a rear edge on the rear wall side of the rod, wherein the flat plate portion is formed in a wedge shape such that the thickness between the upper surface and the lower surface gradually increases from the front edge to the rear edge side, and thereby the gap is formed in a wedge shape such that the gap gradually decreases from the front edge to the rear edge side. Claim 4 In claim 3, the spacer member also has a coupling protrusion formed protruding downward at its rear end, and the coupling protrusion is formed in a wedge shape such that its width in the front-rear direction gradually narrows toward the lower front end by means of a first surface installed upright downward from the rear end edge and a second surface installed upright downward from the rear edge of the lower surface, and the rod front end surface of the attachment part is formed by a flat surface portion extending perpendicular to the central axis from the front edge side to the rear edge side and an inclined surface portion inclined such that the width in the front-rear direction of the attachment part gradually widens from the rear edge of the flat surface portion toward the base side of the attachment part, and when the valve plate is fixedly attached to the attachment part of the valve rod by screwing the valve plate fixing screw into the screw hole, the coupling protrusion of the spacer member is pressed between the rear wall surface of the attachment hole and the inclined surface portion of the rod front end surface, thereby the first surface of the coupling protrusion is pressed against the rear wall surface of the hole Attachment structure of a valve plate to a valve rod in a gate valve, characterized in that, in addition to being press-welded, the second surface of the coupling protrusion is press-welded to the inclined surface. Claim 5 A structure for attaching a valve plate to a valve rod in a gate valve, characterized in that, in the spacer member, the first surface of the coupling protrusion forms an acute angle with the upper surface of the flat plate and also forms a right angle with the lower surface of the flat plate. Claim 6 In claim 1, the valve plate fixing screw has a screw body portion that is screw-coupled to the screw hole and an operating screw head portion integrally connected to the base of the screw body portion; the screw body portion has a male screw portion with screw threads formed on its outer circumference and a cylindrical shaft portion installed adjacent to the base side than the male screw portion; the screw hole has a female screw portion with screw threads formed on its inner circumference for screw-coupled to the male screw portion and a cylindrical portion with a circular cross-section installed adjacent to the rod end surface side than the female screw portion; a screw thread capable of screw-coupled to the male screw portion of the valve plate fixing screw is formed on the inner circumference of the through hole of the spacer member; and the length of the male screw portion of the valve plate fixing screw in the direction of the central axis is formed to be shorter than the length of the cylindrical portion of the screw hole, characterized in that the valve plate attachment structure to the valve rod in a gate valve. Claim 7 A gate valve configured to accommodate a valve plate attached to the tip of a valve rod extending in the vertical direction within a valve box, and to open and close a gate opening formed in the side wall of the valve box by the valve plate, wherein the valve plate is attached to the valve rod by an attachment structure described in claim 1.

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