JP3728668B2 - Pipe fitting - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a pipe joint.
[0002]
[Prior art]
Conventionally, as a pipe joint, a pair of tubular joint members each provided with an annular protrusion for holding a gasket on the butt end face, an annular gasket interposed between the butt end faces of both joint members, and both joint members The inner diameters of both joint members, both gasket holding annular projections and gaskets are equal, and each gasket holding annular projection is in contact with the entire circumference of the inner edge of the gasket. It has been known.
[0003]
6 and 7 show a conventional pipe joint. In the drawing, (42) shows a joint member, (44) shows an annular protrusion for holding a gasket, and (45) shows an annular gasket.
[0004]
[Problems to be solved by the invention]
In the above-mentioned conventional pipe joint, the annular protrusions (44) for holding the gaskets are in contact with the entire circumference of the inner edge of the gasket (45). This is because the gasket (45) is flush with the pipe joint so that there is no recess that becomes a liquid pool.
[0005]
However, in the conventional pipe joint, as shown in FIG. 6, the force acting on the annular ring (44) for holding the gasket during screw tightening is not only in the axial direction (rightward in FIG. 6) but also inward (FIG. 6). (Downwardly facing component), the gasket-pressing annular protrusion (44) is deformed inwardly. On the other hand, the gasket (45) is most deformed at the inner edge portion where each of the gasket holding annular projections (44) first contacts. As a result, each annular ring for holding the gasket (44) is separated from the inner edge of the gasket (45), and when the fitting of the fitting is completed, as shown in FIG. 7, the annular ring for holding the gasket (44) and the gasket (45 ) To form an annular recess (S) that becomes a liquid pool.
[0006]
An object of the present invention is to provide a pipe joint that eliminates a recess due to deformation of the gasket and each annular ring for holding the gasket, and does not have a recess that becomes a liquid pool when tightening is completed.
[0007]
[Means for Solving the Problems]
A pipe joint according to the present invention includes a pair of tubular joint members each having an annular protrusion for holding a gasket on the butt end face, an annular gasket interposed between the butt end faces of both joint members, and both joint members Each gasket holding annular projection includes an inner peripheral surface connected to the inner peripheral surface of each joint member, and a seal surface in close contact with the gasket end surface radially outward from the inner peripheral surface. In the pipe joint, the inner diameter of the gasket and the inner diameter of each joint member before tightening are made equal, and the seal surface has a convex arc shape in cross section and is most protruded radially outward from the inner edge, When the most protruding end of the sealing surface abuts on the gasket end surface, it is between the radially inner portion of the sealing surface and the radially inner portion of the gasket end surface. Gap is formed, the gasket, so that this gap is eliminated during tightening completion, the radially inner portion of the end face is characterized in that the deformation in the axial direction.
[0008]
It is preferable that the seal surface of the protrusion has an arc shape whose cross section is larger than ¼ circle, and the center of the arc is provided at a diameter larger than the inner diameter of the joint member .
[0009]
[Action]
According to the pipe joint of the present invention, when the screw is tightened, as shown in FIG. 4, the most projecting end (P) of the seal surface (34b) of the gasket holding annular projection (34) is the end surface of the gasket (20). In this case, a gap (G1) is formed between the radially inner portion of the seal surface (34b) and the radially inner portion of the gasket (20) end surface from the most projecting end (P) of the seal surface (34b). Furthermore, when the screw is tightened, the force acting on the sealing surface (34b) is slightly outward from the axial direction at the radially inner part from the most protruding end (P), and radially outward from the most protruding end (P). Is slightly inward from the axial direction, and the resultant force acting on the gasket-pressing annular projection (34) is substantially in the axial direction (rightward in FIG. 4). Therefore, the annular ring (34) for holding the gasket hardly deforms inward in the radial direction, and the gasket (20) is most recessed at the radially inner portion where the most projecting end (P) first contacts. When the tightening is completed, as shown in FIG. 5, the gap (G1) is eliminated, and the inner periphery (34a) of the gasket holding annular projection (34) and the inner periphery of the gasket (20) are substantially flush with each other.
[0010]
【Example】
Embodiments of the present invention will be described below with reference to the drawings. In the following description, the left and right in FIG.
[0011]
As shown in FIGS. 1 to 5, the pipe joint includes a first tubular joint member (31) and a second tubular joint member (32), a right end surface of the first tubular joint member (31), and a second tubular joint. An annular gasket (20) interposed between the left end surface of the member (32) and a retainer (5) that holds the annular gasket (20) and is held by the first tubular joint member (31). The second joint member (32) is fixed to the first joint member (31) by a nut (4) screwed into the first joint member (31) from the second joint member (32) side. Yes. An annular protrusion (33) (34) for holding the gasket is formed on the inner peripheral portion of the abutting end surface of each joint member (31) (32), and an annular protrusion (35 for preventing overtightening) is formed on the outer peripheral portion. ) (36) are formed.
[0012]
The gasket (20) has an inner ring part (22) whose inner diameter is equal to the inner diameter of each joint member (31) (32), and its left and right sides are axially (right and left) from the left and right sides of the inner ring part (22). ) Consists of an outer annular part (21) projecting outward and a tapered part (23) between the outer annular part (21) and the inner annular part (22). 22) and the left and right sides of the taper portion (23) receive the gasket pressing annular projections (33) and (34). The amount of protrusion of the outer ring part (21) on the left and right sides of the inner ring part (22) on the left and right faces is determined by the appropriate height from the height of the annular ring for holding the gasket (33) (34). It is made slightly larger than that obtained by subtracting the amount of movement in the axial direction of each joint member (31) (32) relative to (20). A retaining portion (24) made of an outward flange is provided on the outer peripheral surface of the outer annular portion (21). Therefore, even when the gasket (20) is strongly pressed against the retainer (5), the gasket (20) does not fall off from the right side of the retainer (5), and the gasket (20) is held by the retainer (5). The work of holding the retainer (5) on each joint member (31) (32) is easy. The gasket (20) is made of nickel and is subjected to silver plating if necessary. As the material of the gasket (20), austenitic stainless steel, copper, an aluminum alloy, or the like is appropriately employed.
[0013]
The retainer (5) is integrally formed of a stainless steel plate, and has a ring portion (25) and a gasket provided with three claws (28) provided inwardly projecting at the right end of the ring portion (25). The gasket holding part (26) holding the outer peripheral surface of (20) and the joint member holding part (29) adapted to engage with the right end face of the first tubular joint member (31). The three claws (28) have some elasticity, and a bent portion (28a) having some elasticity bent to the right is provided at the tip of each claw (28). Then, the gasket (20) is fitted inside each claw (28), the bent portion (28a) is brought into close contact with the gasket (20), and the radial direction and axial direction of the gasket (20) in the retainer (5) Movement to is blocked. The annular portion (25) is provided with a pair of axial notches at positions where the three claws (28) are provided, and the three claw-shaped holding portions (30) formed thereby. Thus, the joint member holding portion (29) is configured. The three claw-shaped holding portions (30) hold the retainer (5) on the first tubular joint member (31) by scuffing the outer surface of the right end portion of the first joint member (31) with elastic force.
[0014]
An inward flange (11) is formed at the right end of the nut (4), and this flange (11) is fitted around the second joint member (32). A female screw (12) is formed on the inner periphery of the left end of the nut (4), and this is screwed into a male screw (14) formed on the right side of the first joint member (31). An outward flange (13) is formed on the outer periphery of the left end of the second joint member (32), and a thrust ball bearing for preventing co-rotation between this and the inward flange (11) of the nut (4) (6) is interposed.
[0015]
The annular protrusions (33), (34) for each gasket retainer have inner peripheral surfaces (33a) (34a) extending slightly from the inner peripheral surfaces of the respective joint members (31), (32) and inner peripheral surfaces ( 33a) and (34a) are provided with sealing surfaces (33b) and (34b) in close contact with the end face of the gasket (20) on the radially outer side. The seal surfaces (33b) and (34b) have an arc shape whose cross section is larger than a quarter of the circle, and the center of the arc is provided at a diameter larger than the inner diameter of the joint members (31) and (32). Thus, the seal surfaces (33b) and (34b) are projected most outward in the radial direction from the inner edge. As the nut (4) is tightened, the projecting end (P) of the sealing surface (33b) (34b) first comes into contact with the gasket (20), but at this point, the sealing surface (33b) (34b) A gap (G1) is formed between the radially inner part of the projecting end (P) and the radially inner part of the end face of the gasket (20) opposite thereto. When the most projecting end (P) of the seal surface (33b) (34b) comes into contact with the gasket (20), the gasket out of the seal surfaces (33b) (34b) of the annular protrusions (33) (34) for holding the gasket A slight gap (G2) is also formed between the portion (20) facing the taper portion (23) and the taper portion (23) of the gasket (20) (see FIG. 4). .
[0016]
Each of the over-tightening prevention annular protrusions (35) and (36) protrudes inward in the left-right direction more than the gasket retainer annular protrusions (33) and (34), and should be tightened further than proper tightening. Further, the retainer (5) is pressed from both sides. The over-tightening prevention annular protrusions (35) and (36) protect the gasket retainer annular protrusions (33) and (34) of each joint member (31) and (32) before assembly. The gasket pressing annular projections (33) and (34) are prevented from being damaged.
[0017]
The force acting on each sealing surface (33b) (34b) when tightening the nut (4) is slightly outward from the axial direction at the radially inner part from the most protruding end (P), and the most protruding end (P) The radially outer portion is slightly inward from the axial direction, and the resultant force acting on the gasket pressing annular protrusion (34) is substantially in the axial direction (rightward in FIG. 4). As the nut (4) is tightened, the annular ring (34) for holding the gasket is hardly deformed inward, and the gasket (20) is most recessed at the part where the most protruding end (P) first contacts. As a result, the gap (G1) becomes smaller. By tightening the nut (4) with an appropriate amount, the gap (G1) is eliminated, and the inner circumference (33a) (34a) of each gasket retainer ring projection (33) (34) is deformed so that its taper angle decreases. Thus, the inner periphery of each joint member (31) (32) and the inner periphery of the gasket (20) are substantially flush. In this manner, when tightening is completed, there is no recess that becomes a liquid pool between the gasket pressing annular protrusions (33) and (34) and the gasket (20) (see FIG. 5).
[0018]
In the above embodiment, the gasket (20) and the ring-shaped protrusions (33) (34) for holding the gasket are set with the gasket (20) and the ring-shaped protrusions for holding the gasket (when the tightening torque is set to an appropriate value). 33) The gap (G1) (G2) with (34) is determined to be eliminated.
[0019]
The dimensions of the cross section of each gasket holding annular projection (33) (34) are, for example, a taper of a straight portion of 5 °, a projection height of 0.5 mm, an arc radius of 0.5 mm, and the center of the arc at each joint member (31) It is made 0.3 mm larger than the inner diameter of (32).
[0020]
In the above-described embodiment, the inner peripheral surfaces (33a) (34a) of the annular protrusions (33) (34) for each gasket presser are tapered surfaces extending to the tip side. 31) (32) It may be completely flush with the inner circumference. Further, the sealing surfaces (33b) (34b) of the annular protrusions (33) (34) for each gasket pressing may partially include straight portions, and are close to the most protruding ends of the respective sealing surfaces (33b) (34b). The cross-sectional shape may be a straight line instead of an arc.
[0021]
【The invention's effect】
According to the pipe joint of the present invention, when the tightening is completed, the inner periphery of the annular ring for holding the gasket and the inner periphery of the gasket are almost flush with each other, and there is no recess that becomes a liquid pool. Therefore, the fluid flowing in the pipe and the fluid remaining in the recess are not mixed and the purity is not lowered, and the reaction product is not generated by the reaction, so that it can be used for piping that requires high cleanliness.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a pipe joint according to the present invention.
FIG. 2 is an exploded perspective view of the main part of FIG.
FIG. 3 is an enlarged cross-sectional view of a main part of FIG.
4 is an enlarged cross-sectional view of a main part showing a state during tightening of the pipe joint of FIG. 1;
FIG. 5 is an enlarged cross-sectional view of a main part showing a state when tightening of the pipe joint of FIG. 1 is completed.
FIG. 6 is an enlarged cross-sectional view of a main part showing a state during tightening of a conventional pipe joint.
FIG. 7 is an enlarged cross-sectional view of a main part showing a state when tightening of a conventional pipe joint is completed.
[Explanation of symbols]
(4) Nut
(20) Annular gasket
(31) (32) Tubular joint member
(33) (34) Annular projection for holding gasket
(33a) (34a) Inner peripheral surface of protrusion
(33b) (34b) Projection seal surface
(P) Most protruding end
(G1) Gap

Claims (2)

Between the butted end surfaces of the pair of tubular joint members (31) and (32), each of which has an annular projection (33) and (34) for holding the gasket, respectively, on the butted end surfaces. An annular gasket (20) to be interposed and screw means for connecting both joint members (31) (32) are provided, and each annular ring (33) (34) for holding the gasket is connected to each joint member (31) ( 32) inner peripheral surfaces (33a) (34a) continuous to the inner peripheral surface, and sealing surfaces (33b) (34b) in close contact with the end surfaces of the gasket (20) on the radially outer side from the inner peripheral surfaces (33a) (34a). In the pipe joint having the above, the inner diameter of the gasket (20) and the inner diameter of each joint member (31) (32) before tightening are made equal, and the sealing surfaces (33b) (34b) have a convex arc shape in cross section. And the most protruding end (P) of the seal surface (33b) (34b) is in contact with the end surface of the gasket (20). 34b) A gap (G1) is formed between the radially inner part from the protruding end (P) and the radially inner part of the end face of the gasket (20), so that the gasket (20) disappears when tightening is completed. And a radially inner portion of the end face is deformed in the axial direction. Protrusion (33) (34) Sealing surface (33b) (34b) Is an arc shape whose cross section is larger than 1/4 circle, and the center of the arc (O) The pipe joint according to claim 1, wherein is provided at a diameter larger than the inner diameter of the joint member.

Images