JP7702333B2 - Press ring, pipe joint, and pipe joining method - Google Patents

Description

The present invention relates to a press ring used in a pipe joint having a socket and a spigot, a pipe joint equipped with a press ring, and a method for joining pipes using a press ring.

Conventionally, as shown in FIG. 18, this type of pipe joint has, for example, a pipe insertion port 112 of one pipe 111 inserted into a pipe receiving port 114 of the other pipe 113, a rubber seal member 115 inserted between the outer periphery of the pipe insertion port 112 and the inner periphery of the pipe receiving port 114, and a pressure ring 116 fitted onto the pipe insertion port 112 so as to face the open end face 117 of the pipe receiving port 114 from the outside, and connected to the pipe receiving port 114 by a number of bolts 118 and nuts 119.

The pressing ring 116 has a circular pressing ring body 116a, a pressing surface 120 that contacts and presses the sealing member 115, first and second contact portions 121, 122 that contact the opening end surface 117 of the receiving port 114, and a number of bolt insertion holes 123 through which the bolts 118 are inserted. The pressing surface 120 and the first and second contact portions 121, 122 are provided on the same side of the pressing ring body 116a (the side facing the receiving port 114).

Of these, the first abutment portion 121 is located outside the bolt insertion hole 123 in the radial direction 124, and the second abutment portion 122 is located inside the bolt insertion hole 123 in the radial direction 124. The first and second abutment portions 121, 122 abut against the opening end surface 117 of the socket 114, thereby maintaining a predetermined distance between the pressing surface 120 and the opening end surface 117 of the socket 114.

The bolt 118 is inserted through the bolt insertion hole 123 of the pressure ring 116, and by tightening the nut 119, the pressure surface 120 of the pressure ring 116 comes into contact with the seal member 115, forcing the seal member 115 between the outer periphery of the insertion port 112 and the inner periphery of the receiving port 114.

The above-mentioned pressure ring 116 and pipe joint 110 are described, for example, in Patent Document 1 below.

Patent Publication No. 2021-67282

However, in the conventional type described above, when multiple pipes 111, 113 are joined together to form a curved pipe line 130 as shown in FIG. 19, these pipes 111, 113 are joined together with the pipe axis 111a of one pipe 111 inclined relative to the pipe axis 113a of the other pipe 113 as shown in FIG. 20.

At this time, as shown in FIG. 20, when the outer periphery of one tube 111 abuts against the corner portion 128 between the inner periphery 116b of the pressing ring 116 and the surface 126 on the opposite side of the pressing surface 120, it is difficult to further increase the inclination angle α of the tube axis 111a of one tube 111 relative to the tube axis 113a of the other tube 113. It is possible to increase the inclination angle α by increasing the diameter (inner diameter) of the inner periphery 116b of the pressing ring 116, but in this case, the gap 129 (see FIG. 18) between the inner periphery 116b of the pressing ring 116 and the outer periphery of one tube 111 also increases, so there is a risk that the sealing member 115 will enter the gap 129 from the pressing surface 120 of the pressing ring 116, and the sealing member 115 will not be able to be fully inserted between the outer periphery of the insertion port 112 and the inner periphery of the receiving port 114.

In addition, if the bolt 118 and nut 119 are tightened too much, excessive tightening force will be applied to the pressure ring body 116a, which may cause the pressure ring body 116a to deform around the bolt insertion hole 123.

The present invention aims to provide a press ring, pipe fitting, and pipe joining method that can increase the inclination angle when joining pipes at an angle, can fully insert a sealing member between the outer periphery of the insertion port and the inner periphery of the receiving port, and can prevent deformation of the press ring body.

In order to achieve the above object, the first invention is used in a pipe fitting in which a plug is inserted into a socket and a seal member is inserted between an outer periphery of the plug and an inner periphery of the socket,
A press ring is fitted onto the insertion port so as to face the open end surface of the receiving port from the outside and is connected to the receiving port by a plurality of fasteners to press the seal member into the inner side of the receiving port,
The annular pressing ring body is formed with a pressing surface for pressing the seal member, a plurality of fastener insertion holes through which fasteners are inserted, and a contact portion for contacting the open end surface of the receiving port,
The fastener insertion hole is located between the pressing surface and the outer circumferential edge of the pressing ring body in the radial direction of the pressing ring body,
A first tapered surface and a straight surface connected to the first tapered surface on a side closer to the pressing surface than the first tapered surface are formed on the inner circumference of the pressing ring body over the entire circumference,
The first tapered surface is a conical circumferential surface that increases in diameter from a side closer to the pressing surface to a side farther away from the pressing surface,
The straight surface is a cylindrical circumferential surface having a constant inner diameter and extending in the axial direction of the press ring,
When the insertion port is inserted into the receiving port and the outer periphery of the insertion port abuts against the inner periphery of the press ring with the pipe axis of either the insertion port or the receiving port inclined relative to the pipe axis of the other port, the outer periphery of the insertion port abuts against the boundary portion where the first tapered surface and the straight surface are connected,
The contact portion is provided so as to surround at least the periphery of each fastener insertion hole.

With this, the insertion port of one pipe is inserted into the receiving port with the pipe axis of the insertion port inclined relative to the pipe axis of the receiving port of the other pipe, and the fastener is inserted into the fastener insertion hole of the press ring and tightened, connecting the press ring to the receiving port and inserting a sealing member between the outer periphery of the insertion port and the inner periphery of the receiving port, thereby joining one pipe to the other pipe.

In this case, since a tapered surface is formed on the inner circumference of the pressing ring body, when the outer circumference of one tube abuts against the inner circumference of the pressing ring, the abutment point is closer to the pressing surface than the corner between the inner circumference of the pressing ring and the surface opposite to the pressing surface. This makes it possible to increase the inclination angle of the tube axis of one tube with respect to the tube axis of the other tube when the outer circumference of one tube abuts against the inner circumference of the pressing ring, and when multiple tubes are joined together at an inclination to form a curved pipeline, the number of tubes can be reduced. In addition, when the insertion port of one tube is inserted into the receiving port with the tube axis of the insertion port of the other tube inclined with respect to the tube axis of the receiving port of the other tube, and one tube and the other tube are joined, the outer circumference of one tube does not abut against the inner periphery of the pressing surface of the pressing ring, but abuts against the boundary part between the straight surface and the tapered surface on the inner circumference of the pressing ring. This makes it possible to prevent the inner peripheral edge of the pressing surface of the press ring from being damaged, and allows the sealing member to be inserted sufficiently between the outer periphery of the insertion port and the inner periphery of the receiving port by the pressing surface of the press ring.

In addition, since there is no need to increase the inner diameter of the pressure ring to increase the inclination angle, the gap between the inner circumference of the pressure ring and the outer circumference of one of the tubes does not expand, and the sealing material is prevented from entering the gap from the pressing surface of the pressure ring. This allows the sealing material to be inserted sufficiently between the outer circumference of the insertion port and the inner circumference of the receiving port.

In addition, by contacting the contact portion with the open end surface of the receiving port, the distance from the pressing surface to the open end surface of the receiving port is maintained at a specified distance. In this case, even if the fastener is overtightened and an excessive tightening force acts on the pressing ring body, the contact portion is arranged to surround at least the periphery of each fastener insertion hole, so that the pressing ring body can be prevented from deforming around the fastener insertion hole.

In the second aspect of the present invention, the contact portion of the pressure ring is provided in the area between the fastener insertion hole and the adjacent fastener insertion hole in the circumferential direction of the pressure ring body.

This prevents the ring body from deforming in the area between the fastener insertion hole and the adjacent fastener insertion hole, even if the fastener is overtightened and an excessive tightening force acts on the ring body.

In the third invention, the contact portion of the pressure ring is provided in the area from the outer periphery of the pressing surface to the outer periphery of the pressure ring body in the radial direction, excluding the fastener insertion hole.

This prevents deformation of the pressing ring body in the area from the outer edge of the pressing surface to the outer edge of the pressing ring body, even if the fastener is tightened too much and an excessive tightening force is applied to the pressing ring body.

The present invention is a pipe joint provided with the press ring according to any one of the first to fourth aspects of the present invention,
A second tapered surface is formed on the inner circumference of the socket, the diameter of which decreases toward the back of the socket.
A space for inserting a seal member is formed between the second tapered surface and the outer periphery of the insertion port over the entire periphery,
A seal member is inserted into the seal member insertion space,
The seal member has a valve portion at one end in the insertion direction that is compressed in the pipe diameter direction to exert a sealing function, and a guide portion is formed on the inner periphery of the receiving port to guide the valve portion of the seal member from the open end face of the receiving port to the seal member insertion space,
The guide portion has a third tapered surface that decreases in diameter toward the back of the socket,
the third tapered surface is formed between the opening end surface of the receiving port and the second tapered surface in the tube axial direction;
The inclination angle of the third tapered surface relative to the tube axis is larger than the inclination angle of the second tapered surface relative to the tube axis.

When the seal member is pushed into the seal member insertion space by the pressure ring, the valve portion of the seal member is guided from the opening end face of the receiving port into the seal member insertion space by the third tapered surface of the guide portion.

As a result, even if the fastener is unbalanced when fastening the press ring to the receiving port, causing the seal member to stretch and become loose, the valve portion of the seal member is guided from the opening end face of the receiving port into the seal member insertion space by the third tapered surface of the guide portion, so the seal member can be reliably pushed into the seal member insertion space by the press ring.

In the pipe joint of the sixth invention, the fastener insertion hole of the press ring is located radially outward of the press ring body relative to the pressing surface,
the contact portion of the press ring is provided in a region from the outer circumferential edge of the pressing surface to the outer circumferential edge of the press ring body in the radial direction of the press ring body, excluding the fastener insertion hole;
The pressing surface is formed in a recess surrounded by the contact portion,
The other end of the seal member is fitted into the recess of the press ring.

When the pressure ring presses the seal member into the seal member insertion space, the other end of the seal member is fitted into the recess of the pressure ring, so it is fixed to the pressure ring without shifting in position in the radial direction. This allows the seal member to be reliably inserted into the seal member insertion space.

The pipe fitting in the seventh invention has a gap formed between the inner circumferential surface of the contact portion of the press ring, the third tapered surface of the receiving port, and the outer circumferential surface of the seal member.

As a result, even if the seal member deforms radially outward when the seal member is pushed into the seal member insertion space by the pressure ring, the seal member escapes into the gap, preventing the seal member from being pinched between the contact portion of the pressure ring and the opening end face of the receiving port.

In the pipe fitting of the eighth invention, the diameter of the end of the third tapered surface on the open end face side of the receiving port is smaller than the inner diameter of the contact portion of the press ring.

As a result, when the seal member is pushed into the seal member insertion space with the pressure ring, the gap formed between the seal member and the third tapered surface becomes smaller, so even if the fastener is unbalanced when fastening the pressure ring to the receiving port, the seal member is prevented from curling up due to unbalanced tightening, and the seal member is prevented from being pinched between the contact part of the pressure ring and the opening end face of the receiving port.

The ninth invention is a method for joining pipes using the press ring according to any one of the first to fourth inventions,
The insert is inserted into the socket with the axis of one of the insert and the socket inclined relative to the axis of the other.
By inserting the fastener into the fastener insertion hole of the press ring and tightening it, the press ring is connected to the receiving port and the sealing member is inserted between the outer periphery of the receiving port and the inner periphery of the receiving port.

By doing this, before inserting the sealing member between the outer periphery of the insertion port and the inner periphery of the receiving port, the insertion port is inserted into the receiving port with the pipe axis of either the insertion port or the receiving port tilted relative to the pipe axis of the other port, thereby reducing the force required to tilt the insertion port relative to the receiving port.

Instead of the above-mentioned pipe joining method, for example, first insert the insertion port into the receiving port with the pipe axis of either the insertion port or the receiving port aligned without tilting it relative to the pipe axis of the other port, then insert a seal member between the outer periphery of the insertion port and the inner periphery of the receiving port, and then tilt the pipe axis of either the insertion port or the receiving port relative to the pipe axis of the other port. In this case, one of the insertion port or the receiving port is tilted relative to the other port against the seal member, which creates a problem in that the force required to tilt one of the insertion port or the receiving port relative to the other increases.

As described above, the present invention makes it possible to increase the angle of inclination when joining pipes at an angle, and to fully insert the sealing member between the outer periphery of the insertion port and the inner periphery of the receiving port. Furthermore, deformation of the pressing ring body can be prevented.

1 is a cross-sectional view of a pipe joint according to a first embodiment of the present invention. FIG. 11 is a partially enlarged cross-sectional view of the insertion port, the receiving port, the seal member, and the press ring of the pipe joint of the first embodiment, showing the state immediately before the seal member is inserted into the seal member insertion space. FIG. FIG. 4 is an enlarged cross-sectional view of a portion of the socket of the pipe joint according to the first embodiment. FIG. FIG. 6 is a view taken along the line XX in FIG. 5. 6 is a view taken along the line YY in FIG. 5. 10 is a cross-sectional view showing a method for joining pipes of a pipe joint in accordance with the first embodiment, illustrating a state in which a seal member is pressed into a seal member insertion space by a pressure ring. 13 is a cross-sectional view of the sealing member of the pipe joint according to the first embodiment when it is deformed outward and escapes into a gap. FIG. 10 is a cross-sectional view showing a method for joining pipes of a pipe joint in accordance with the first embodiment, illustrating a state in which a seal member is pressed into a seal member insertion space by a pressure ring. 10 is a cross-sectional view showing a method for joining pipes of a pipe joint in accordance with the first embodiment, illustrating a state in which a seal member is pressed into a seal member insertion space by a pressure ring. FIG. 11 is a cross-sectional view showing a reference example of the first embodiment of the present invention, illustrating a state in which a seal member is being pressed into a seal member insertion space by a pressing ring. FIG. 11 is a cross-sectional view showing a reference example of the first embodiment, illustrating a state in which the seal member is pressed into the seal member insertion space by the pressing ring. FIG. 5 is a cross-sectional view of a pipe joint according to a second embodiment of the present invention. FIG. FIG. 13 is a partially enlarged front view of a press ring of a pipe joint according to a third embodiment of the present invention. 1 is a cross-sectional view of a conventional pipe joint, showing how pipes are joined in a straight line. 13 is a diagram of a curved pipe formed by joining multiple pipes. FIG. 4 is a cross-sectional view of the pipe joint of the same embodiment, showing how the pipes are joined in an inclined state.

The following describes an embodiment of the present invention with reference to the drawings.

(First embodiment)
In the first embodiment, as shown in Figures 1 to 3, reference numeral 1 denotes a pipe fitting, and in this pipe fitting 1, a spigot 3 formed in one pipe 2 is inserted into a socket 5 formed in the other pipe 4.

The inner circumference of the socket 5 is formed with a second tapered surface 8 that tapers toward the back of the socket 5, a socket protrusion 10, and a lock ring housing groove 11. A seal member insertion space 14 is formed around the entire circumference between the second tapered surface 8 and the outer circumference of the insertion port 3. An annular seal member 15 that seals between the inner circumference of the socket 5 and the outer circumference of the insertion port 3 is inserted into the seal member insertion space 14. The seal member 15 is a rubber ring, and has a valve portion 16 provided at one end in the insertion direction 18, and a base portion 17 provided integrally with the valve portion 16.

The valve portion 16 has a circular cross section, and the base portion 17 has a trapezoidal cross section. When the seal member 15 is inserted into the seal member insertion space 14, the valve portion 16 is compressed in the pipe radial direction 19 to provide a sealing function.

The socket 5 has multiple bolt holes 25 through which the T-head bolts 22 are inserted.

The lock ring accommodation groove 11 is formed on the inner side of the receiving port 5 relative to the seal member insertion space 14, and the lock ring accommodation groove 11 accommodates a lock ring 26. The lock ring 26 is a ring with a one-piece structure cut in one place, and has elasticity such that the diameter can be expanded by expanding the width of the cut part with a diameter expander (not shown), and the diameter can be reduced by removing the diameter expander from the cut part, returning it to its original diameter.

The insertion port 3 penetrates the seal member 15, the lock ring 26, and the backup ring 29, and a insertion port protrusion 27 is formed around the entire outer periphery of the tip of the insertion port 3. The insertion port protrusion 27 can engage with the lock ring 26 from the back side of the receiving port 5 in the removal direction 28 of one of the pipes 2, thereby preventing the insertion port 3 from coming off the receiving port 5 in the event of an earthquake, etc.

The socket protrusion 10 protrudes inward in the pipe diameter direction 19 from the inner circumference of the socket 5, and is formed around the entire circumference between the seal member insertion space 14 and the lock ring housing groove 11. The backup ring 29 is fitted onto the socket 3, and is disposed between the inner circumference of the socket protrusion 10 and the outer circumference of the socket 3, adjacent to the lock ring 26. The backup ring 29 is a ring with a one-piece structure cut at one point, and is made of a material such as elastic resin.

A guide portion 31 that guides the valve portion 16 of the seal member 15 from the opening end face 21 of the receiving port 5 to the seal member insertion space 14 is formed on the inner circumference of the receiving port 5. The guide portion 31 has a third tapered surface 32 that narrows in diameter toward the back of the receiving port 5. The third tapered surface 32 is formed over the entire circumference in the tube axis direction 50 between the opening end face 21 of the receiving port 5 and the second tapered surface 8. As shown in FIG. 4, the inclination angle B of the third tapered surface 32 relative to the tube axis 4a of the other tube 4 is greater than the inclination angle C of the second tapered surface 8 relative to the tube axis 4a.

The pressing ring 20, which presses the sealing member 15 from the opening end surface 21 of the receiving port 5 into the sealing member insertion space 14, is fitted onto the insertion port 3 and faces the opening end surface 21 of the receiving port 5 from the outside. The pressing ring 20 is fastened to the receiving port 5 via a number of T-head bolts 22 (an example of a fastener) and nuts 23 (an example of a fastener), and as shown in Figures 5 to 8, has an annular pressing ring body 35, a pressing surface 36 that presses the sealing member 15, a number of bolt insertion holes 37 (fastener insertion holes) through which the T-head bolts 22 are inserted, and a contact portion 38 that contacts the opening end surface 21 of the receiving port 5.

The pressing ring body 35 has multiple protrusions 40 on its outer periphery that protrude radially outward. The pressing surface 36 is formed in an annular shape along the inner periphery 41 of the pressing ring body 35.

In addition, each bolt insertion hole 37 is located between the pressing surface 36 and the outer peripheral edge 39 of the pressing ring body 35 in the radial direction 46 of the pressing ring body 35. The protrusions 40 of the pressing ring body 35 are arranged to correspond to the bolt insertion holes 37.

The contact portion 38 is provided over the entire area from the outer circumferential edge 42 of the pressing surface 36 to the outer circumferential edge 39 of the pressing ring body 35 in the radial direction 46 of the pressing ring body 35, excluding the bolt insertion hole 37. The pressing surface 36 is formed in a recess 43 surrounded by the contact portion 38, and is recessed one step further than the surface of the contact portion 38 in the thickness direction 55 of the pressing ring body 35 (the same direction as the tube axis direction 50 in Figures 7 and 8). The inner circumferential surface 44 of the contact portion 38 is a tapered surface that expands in the insertion direction 18 (see Figure 3).

The contact portion 38 and the recess 43 are formed on the joint surface side of the press ring 20 that faces the opening end surface 21 of the receiving port 5.

The base 17 (other end) of the seal member 15 is fitted into the recess 43 of the press ring 20. A gap 45 is formed around the entire circumference, surrounded by the inner surface 44 of the contact portion 38 of the press ring 20, the third tapered surface 32 of the receiving port 5, and the outer surface of the base 17 of the seal member 15.

As shown in FIG. 3, the diameter D2 of the end of the third tapered surface 32 on the opening end surface 21 side of the receiving port 5 is smaller than the inner diameter D1 of the contact portion 38.

As shown in Figures 6 to 8, a first tapered surface 47 and a straight surface 48 are formed around the entire inner circumference 41 of the pressing ring body 35. The first tapered surface 47 expands in diameter from the side closer to the pressing surface 36 to the opposite side, reaching a surface 49 on the opposite side of the pressing surface 36.

The straight surface 48 has a constant inner diameter d, is parallel to the tube axis 4a of the other tube 4, and is formed with a predetermined width W in the tube axis direction 50. It is located closer to the pressing surface 36 than the first tapered surface 47 and reaches the pressing surface 36.

A method for joining the pipes 2, 4 using the pressure ring 20 will be described below.
First, the pressure ring 20, the seal member 15 and the backup ring 29 are fitted onto the insertion port 3 of one of the pipes 2, and the lock ring 26 is attached to the lock ring accommodating groove 11 of the receiving port 5 of the other pipe 4, and the lock ring 26 is expanded in diameter using a diameter expander (not shown).

Then, insert port 3 is inserted into socket 5 with the pipe axis 2a of insert port 3 inclined relative to the pipe axis 4a of socket 5. At this time, because the lock ring 26 has an expanded diameter, insert port protrusion 27 passes through the inner circumference of lock ring 26 from the open end surface 21 side of socket 5 to the back side.

Then, by removing the expander (not shown), the lock ring 26 shrinks in diameter and hugs the outer circumference of the insertion port 3.

Next, as shown in FIG. 9, the backup ring 29 is moved in the tube axis direction 50 and inserted into the receiving port 5 so that it is adjacent to the lock ring 26. Furthermore, the seal member 15 is moved in the tube axis direction 50 so that it is positioned in front of the opening end surface 21 of the receiving port 5.

Then, insert the T-head bolt 22 through the bolt hole 25 of the socket 5 and the bolt insertion hole 37 of the pressure ring 20, screw the nut 23 onto the T-head bolt 22, and tighten the nut 23 until the contact portion 38 of the pressure ring 20 abuts against the open end surface 21 of the socket 5.

As a result, as shown in Figures 1 and 2, the pressure ring 20 is connected to the receiving port 5, and the pressure surface 36 of the pressure ring 20 presses the seal member 15 and inserts it into the seal member insertion space 14, and one pipe 2 and the other pipe 4 are joined together with the pipe axis 2a of the insertion port 3 inclined relative to the pipe axis 4a of the receiving port 5.

The following describes the above configuration and the effects of the joining method.

As shown in FIG. 2, the contact portion 38 of the pressure ring 20 contacts the opening end surface 21 of the receiving port 5, so that the distance between the pressure surface 36 of the pressure ring 20 and the opening end surface 21 of the receiving port 5 is maintained at a predetermined distance.

In this case, even if the T-head bolt 22 and nut 23 are overtightened and an excessive tightening force acts on the pressing ring body 35, the pressing ring body 35 can be prevented from deforming in the entire area from the outer periphery 42 of the pressing surface 36 to the outer periphery 39 of the pressing ring body 35.

When the seal member 15 is pressed into the seal member insertion space 14 by the pressing ring 20, the other end of the seal member 15 fits into the recess 43 of the pressing ring 20, so that the seal member 15 is fixed to the pressing ring 20 without shifting in the radial direction 46. This allows the seal member 15 to be reliably inserted into the seal member insertion space 14.

Also, as shown in FIG. 9, when the seal member 15 is pushed into the seal member insertion space 14 by the pressing ring 20, the valve portion 16 of the seal member 15 is guided from the opening end surface 21 of the receiving port 5 into the seal member insertion space 14 by the third tapered surface 32 of the guide portion 31.

In this case, if the T-head bolts 22 and nuts 23 are tightened one-sidedly from the top to the bottom when fastening the pressure ring 20 to the receiving port 5, even if the sealing member 15 stretches and becomes loose, the valve portion 16 is guided from the opening end surface 21 of the receiving port 5 to the sealing member insertion space 14 by the third tapered surface 32 of the guide portion 31, and the sealing member 15 can be reliably pushed into the sealing member insertion space 14 by the pressure ring 20.

This eliminates the need to tighten all T-head bolts 22 and nuts 23 to a uniform tightening torque, eliminates the need to manage the tightening torque of the T-head bolts 22 and nuts 23, and shortens the time required to tighten the T-head bolts 22 and nuts 23.

In addition, when the seal member 15 is pushed into the seal member insertion space 14 by the pressing ring 20, even if the seal member 15 deforms outward in the pipe diameter direction 19 as shown in FIG. 10, the seal member 15 escapes into the gap 45, thereby preventing the seal member 15 from being pinched between the contact portion 38 of the pressing ring 20 and the opening end surface 21 of the receiving port 5.

As shown in Figs. 1 to 3, 7 and 8, the first tapered surface 47 and the straight surface 48 are formed on the inner circumference 41 of the pressing ring body 35, so that when the outer circumference of one tube 2 abuts against the inner circumference 41 of the pressing ring 20, the outer circumference of one tube 2 abuts against the boundary portion 51 between the first tapered surface 47 and the straight surface 48. This boundary portion 51 is closer to the pressing surface 36 than the corner portion 52 between the inner circumference 41 of the pressing ring 20 and the surface 49 on the opposite side of the pressing surface 36. Therefore, it is possible to increase the inclination angle α (see Fig. 1) of the tube axis 2a of one tube 2 with respect to the tube axis 4a of the other tube 4 when the outer circumference of one tube 2 abuts against the inner circumference 41 of the pressing ring 20. This makes it possible to reduce the number of tubes when joining multiple tubes at an angle to form a curved pipe (see Fig. 19).

Furthermore, since the inclination angle α (see FIG. 1) can be increased as described above, even when the pipeline is bent due to an earthquake or the like, one pipe 2 and the other pipe 4 can be bent at a large inclination angle α, thereby reducing the load on the pressure ring 20.

In addition, the outer periphery of one of the tubes 2 does not contact the inner peripheral edge 53 (see Figures 7 and 8) of the pressing surface 36 of the pressing ring 20, but contacts the boundary portion 51, so that the inner peripheral edge 53 of the pressing surface 36 can be prevented from being damaged. This allows the sealing member 15 to be fully inserted into the sealing member insertion space 14 by the pressing surface 36 of the pressing ring 20.

In addition, since there is no need to increase the inner diameter d of the pressing ring 20 (i.e., the inner diameter d of the straight surface 48) to increase the inclination angle α, the gap 54 (see FIG. 1) between the straight surface 48 of the inner circumference 41 of the pressing ring 20 and the outer circumference of one of the tubes 2 does not expand, and the seal member 15 is prevented from entering the gap 54 from the pressing surface 36 of the pressing ring 20. This allows the seal member 15 to be inserted sufficiently into the seal member insertion space 14.

In addition, with the above-described pipe joining method, as shown in FIG. 9, before inserting the seal member 15 into the seal member insertion space 14, the pipe axis 2a of one pipe 2 is tilted relative to the pipe axis 4a of the other pipe 4, and the insertion port 3 is inserted into the receiving port 5. This reduces the force required to tilt the insertion port 3 relative to the receiving port 5.

In addition, instead of the above-mentioned pipe joining method, for example, first insert the insertion port 3 into the receiving port 5 with the pipe axis 2a of one pipe 2 aligned with the pipe axis 4a of the other pipe 4 without tilting it, then insert the seal member 15 into the seal member insertion space 14, and then tilt the pipe axis 2a of one pipe 2 with respect to the pipe axis 4a of the other pipe 4. In this case, the insertion port 3 (one pipe 2) is tilted with respect to the receiving port 5 (the other pipe 4) against the seal member 15, which creates a problem in that the force required to tilt the insertion port 3 with respect to the receiving port 5 increases.

In addition, as shown in FIG. 3, the diameter D2 of the end of the third tapered surface 32 on the side of the opening end surface 21 of the receiving port 5 is smaller than the inner diameter D1 of the contact portion 38, so that when the seal member 15 is pushed into the seal member insertion space 14 by the pressing ring 20, the gap 56 formed between the seal member 15 and the third tapered surface 32 becomes smaller, as shown in FIG. 11.

Therefore, if the T-head bolt 22 and nut 23 are tightened unevenly when fastening the pressure ring 20 to the receiving port 5, as shown in FIG. 12, even if the pressed seal member 15 escapes into the gap 56, it is possible to prevent the seal member 15 from curling up due to uneven tightening. This makes it possible to prevent the seal member 15 from being pinched between the contact portion 38 of the pressure ring 20 and the opening end surface 21 of the receiving port 5.

As a reference example, as shown in FIG. 13, if the relationship between the inner diameter D1 of the contact portion 38 and the diameter D2 of the end of the third tapered surface 32 is reversed, i.e., if the diameter D2 is greater than the inner diameter D1, the gap 56 formed between the seal member 15 and the third tapered surface 32 will be larger when the seal member 15 is pressed into the seal member insertion space 14 by the pressing ring 20.

For this reason, if the T-head bolt 22 and nut 23 are unbalanced when fastening the pressure ring 20 to the socket 5, as shown in Fig. 14, the pressed seal member 15 may escape into the gap 56, causing the seal member 15 to curl up and the inner peripheral surface of the seal member 15 to separate from the outer peripheral surface of the insertion port 3 in the pipe diameter direction 19. If the seal member 15 curls up in this way, it becomes easy for a problem to occur in which the seal member 15 is pinched between the contact portion 38 of the pressure ring 20 and the opening end surface 21 of the socket 5.
Second Embodiment
In the second embodiment, as shown in FIGS. 15 and 16 , a plurality of contact portions 38 of the pressure ring 20 are formed on the pressure ring body 35 in an annular shape so as to surround the periphery of each bolt insertion hole 37 .

With this, the contact portion 38 comes into contact with the open end surface 21 of the socket 5, thereby maintaining a predetermined distance from the pressing surface 36 to the open end surface 21 of the socket 5. At this time, even if the T-head bolt 22 and the nut 23 are overtightened and an excessive tightening force acts on the press ring body 35, the press ring body 35 can be prevented from deforming around the bolt insertion hole 37.
Third Embodiment
In the third embodiment, as shown in FIG. 17 , the contact portion 38 is formed in an annular shape so as to surround each bolt insertion hole 37, and is also formed in the region between the bolt insertion hole 37 and the adjacent bolt insertion hole 37 in the circumferential direction 57 of the pressure ring body 35.

This prevents deformation of the pressure ring body 35 in the area between the bolt insertion hole 37 and the adjacent bolt insertion hole 37, even if the T-head bolt 22 and the nut 23 are overtightened and an excessive tightening force acts on the pressure ring body 35.

In each of the above embodiments, as shown in FIG. 1, the pipe fitting 1 is shown in which the insertion port 3 is joined at an angle to the receiving port 5, but the pipe fitting 1 may also be shown in which the receiving port 5 is joined at an angle to the insertion port 3. Also, the pressure ring 20 shown in each of the above embodiments may be used in a pipe fitting in which the insertion port 3 and the receiving port 5 are joined in a straight line without being inclined.

1 Pipe joint 2a Pipe axis 3 Insertion port 4a Pipe axis 5 Socket port 8 Second tapered surface 14 Seal member insertion space 15 Seal member 16 Valve portion 18 Insertion direction 19 Pipe diameter direction 20 Press ring 21 Open end surface 22 T-head bolt (fastener)
23 Nut (fastener)
31 Guide portion 32 Third tapered surface 35 Press ring body 36 Pressing surface 37 Bolt insertion hole (fastener insertion hole)
38 Contact portion 39 Outer peripheral edge of pressing ring body 42 Outer peripheral edge of pressing surface 43 Recess 44 Inner peripheral surface of contact portion 45 Gap 46 Radial direction 47 First tapered surface 48 Straight surface 50 Tube axial direction 57 Circumferential direction of pressing ring body B Incline angle C of third tapered surface Incline angle D1 of second tapered surface Inner diameter D2 of contact portion Diameter d of third tapered surface Inner diameter

Claims (9)

This is used in a pipe joint in which a plug is inserted into a socket and a seal member is inserted between the outer periphery of the plug and the inner periphery of the socket,
A press ring is fitted onto the insertion port so as to face the open end surface of the receiving port from the outside and is connected to the receiving port by a plurality of fasteners to press the seal member into the inner side of the receiving port,
The annular pressing ring body is formed with a pressing surface for pressing the seal member, a plurality of fastener insertion holes through which fasteners are inserted, and a contact portion for contacting the open end surface of the receiving port,
The fastener insertion hole is located between the pressing surface and the outer circumferential edge of the pressing ring body in the radial direction of the pressing ring body,
A first tapered surface and a straight surface connected to the first tapered surface on a side closer to the pressing surface than the first tapered surface are formed on the inner circumference of the pressing ring body over the entire circumference,
The first tapered surface is a conical circumferential surface that increases in diameter from a side closer to the pressing surface to a side farther away from the pressing surface,
The straight surface is a cylindrical circumferential surface having a constant inner diameter and extending in the axial direction of the press ring,
When the insertion port is inserted into the receiving port and the outer periphery of the insertion port abuts against the inner periphery of the press ring with the pipe axis of either the insertion port or the receiving port inclined relative to the pipe axis of the other port, the outer periphery of the insertion port abuts against the boundary portion where the first tapered surface and the straight surface are connected,
A press ring characterized in that the contact portion is provided so as to surround at least the periphery of each fastener insertion hole. The pressure ring according to claim 1, characterized in that the contact portion is provided in an area between the fastener insertion hole and the adjacent fastener insertion hole in the circumferential direction of the pressure ring body. The pressure ring according to claim 1 or 2, characterized in that the contact portion is provided in the area from the outer periphery of the pressing surface to the outer periphery of the pressure ring body in the radial direction of the pressure ring body, excluding the fastener insertion hole. The inclination angle between the pipe axis of the insertion port and the pipe axis of the receiving port is a predetermined angle,
2. The press ring according to claim 1, wherein the first tapered surface of the press ring is inclined at an angle equal to or greater than the predetermined angle with respect to an axis of the press ring, and the diameter of the end of the first tapered surface that is farther from the open end face of the receiving port is smaller than the diameter of the pressing surface at a radially outer end of the press ring . A pipe joint provided with the pressure ring according to any one of claims 1 to 3 ,
A second tapered surface is formed on the inner circumference of the socket, the diameter of which decreases toward the back of the socket.
A space for inserting a seal member is formed between the second tapered surface and the outer periphery of the insertion port over the entire periphery,
A seal member is inserted into the seal member insertion space,
The seal member has a valve portion at one end in the insertion direction that is compressed in the pipe diameter direction to exert a sealing function, and a guide portion is formed on the inner periphery of the receiving port to guide the valve portion of the seal member from the open end face of the receiving port to the seal member insertion space,
The guide portion has a third tapered surface that decreases in diameter toward the back of the socket,
the third tapered surface is formed between the opening end surface of the receiving port and the second tapered surface in the tube axial direction;
A pipe joint, characterized in that the inclination angle of the third tapered surface relative to the pipe axis is larger than the inclination angle of the second tapered surface relative to the pipe axis. The fastener insertion hole of the press ring is located radially outward of the press ring body relative to the pressing surface,
the contact portion of the press ring is provided in a region from the outer circumferential edge of the pressing surface to the outer circumferential edge of the press ring body in the radial direction of the press ring body, excluding the fastener insertion hole;
The pressing surface is formed in a recess surrounded by the contact portion,
6. A pipe joint according to claim 5, wherein the other end of the seal member is fitted into a recess of the press ring. The pipe fitting according to claim 6, characterized in that a gap is formed between the inner circumferential surface of the contact portion of the press ring, the third tapered surface of the receiving port, and the outer circumferential surface of the seal member. The pipe fitting according to claim 7, characterized in that the diameter of the end of the third tapered surface on the open end face side of the receiving port is smaller than the inner diameter of the contact portion of the press ring. A method for joining pipes using the press ring according to any one of claims 1 to 3 ,
The insert is inserted into the socket with the axis of one of the insert and the socket inclined relative to the axis of the other.
A method for joining pipes, comprising the steps of inserting a fastener into a fastener insertion hole in the pressure ring and tightening it to connect the pressure ring to the receiving port and inserting a sealing member between the outer periphery of the insertion port and the inner periphery of the receiving port.

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