JP7486786B2 - Pipe Fittings - Google Patents

Description

The present invention relates to a pipe fitting for connecting synthetic resin pipes.

As shown in FIG. 10, the pipe joint includes an inner core 21 having a tapered outer surface 21B that fits into the end of a synthetic resin pipe 6 to expand the diameter of the end, a joint body 3 having a tapered inner surface 32A that is inclined in the opposite direction to the tapered outer surface 21B of the inner core 21 at an opening 32K into which the pipe 6 can be inserted, a tightening ring 40 having a tapered outer surface 40B that is inclined in the same direction as the tapered inner surface 32A of the joint body 3 and is fitted onto the pipe 6, and a cap nut 5 that reduces the diameter of the pipe 6 by moving the tightening ring 40 along the tapered inner surface 32A of the joint body 3 toward the tip of the pipe 6 (see, for example, Patent Document 1).

In the pipe joint of the above configuration, as shown in the enlarged view of FIG. 10, the inner surface 40A of the tightening ring 40 is formed in a surface parallel to the axial direction from the leading edge to the trailing edge. The leading edge 40T of the tightening ring 40 has an edge portion 40E in which the angle between the leading surface 40T of the tightening ring 40 and the inner surface 40A is 90 degrees. When tension or compression is applied to the pipe 6 multiple times, the pipe 6 moves back and forth in the axial direction relative to the tightening ring 40. At this time, the edge portion 44E is deeply embedded into the inner diameter side of the pipe 6 as the pipe 6 moves back and forth (see FIG. 11). This causes damage (shaving) to the outer surface of the pipe 6. As a result, the water-stopping performance is reduced and water leakage occurs, leaving room for improvement.

JP 2009-79750 A

In view of the above situation, the present invention aims to provide a pipe fitting that can prevent water leakage even when the pipe is subjected to tension or compression multiple times.

The pipe joint of the present invention, which is intended to solve the above-mentioned problems, is a pipe joint that includes an inner core having a tapered outer surface that fits into the end of a synthetic resin pipe to expand the diameter of the end, a joint body having a tapered inner surface at an opening into which the pipe can be inserted that is inclined in the opposite direction to the tapered outer surface of the inner core, a tightening ring having a tapered outer surface that is inclined in the same direction as the tapered inner surface of the joint body and fitted onto the pipe, and a cap nut that moves the tightening ring along the tapered inner surface of the joint body toward the tip of the pipe to reduce the diameter of the pipe, and is characterized in that the tightening ring has a crest portion located on the inner surface closer to the tip edge in the direction of movement of the tightening ring, the crest portion being located on the inner diameter side of the inner diameter of the tip edge.

According to the present invention, the end of the tube is expanded by the inner core, preventing the tube from coming out of the fitting body. In this state, the clamping ring is moved toward the tip of the tube by the cap nut along the tapered inner surface of the fitting body, and the inner surface of the clamping ring is pressed against the outer surface of the tube, sealing the gap between the tube and the clamping ring. Even if the tube is pulled or compressed multiple times from this state, the tube will abut against the crest located on the inner diameter side of the inner diameter of the tip edge, or the tube will abut against the crest and the tip edge, preventing the tip edge from entering the inner diameter side of the tube and scraping the tube.

The pipe joint of the present invention may also be configured such that the inner surface of the tightening ring before the bent portion in the direction of movement of the tightening ring toward the tip of the pipe is a straight surface that is approximately parallel to the axial direction of the tightening ring.

As described above, the straight inner surface in front of the bent portion allows for smooth insertion of the tube, while the angle between the front side and the tip side of the bent portion can be made larger, reliably preventing the tube from being scraped between the bent portion and the tip edge.

The pipe joint of the present invention may also be configured with a tapered surface between the tip edge of the tightening ring and the bent portion, the diameter of which increases toward the tip.

As described above, if the area between the leading edge of the tightening ring and the folded portion is configured as a tapered surface, when the ring is tightened, the tapered surface comes into contact with the surface of the tube and receives pressure at the tapered surface in a direction that causes the tube to come out. This pressure is distributed at the tapered surface, making it difficult for the tube to be scraped.

In addition, the pipe joint of the present invention may have a virtual inner peripheral tapered surface passing through the leading edge of the tightening ring and the bent portion, which is approximately parallel to the tapered outer surface of the inner core.

As described above, if the imaginary inner tapered surface that passes through the leading edge and the crest of the clamping ring is approximately parallel to the tapered outer surface of the inner core, the tube can be clamped evenly by the crest and leading edge, and scraping of the tube can be more reliably prevented.

According to the present invention, by providing the tightening ring with a crest located on the inner surface closer to the tip edge in the direction of movement of the tightening ring than the inner diameter of the tip edge, it is possible to provide a pipe fitting that can suppress the occurrence of water leakage even if tension or compression is applied to the pipe multiple times.

FIG. 2 is a side view, partially in section, showing the pipe joint of the present invention, showing the state before pipes are connected. FIG. 4 is a side view, partially in section, of a clamping ring provided in the pipe joint. 4 is a cross-sectional view of a main part of the tightening ring. FIG. FIG. FIG. 2 is a side view of the pipe joint, with a portion in cross section, showing the state in which the pipe is disposed in the joint body. FIG. 2 is a side view of the pipe joint, partially in cross section, showing the state in which the cap nut has been tightened to fix the pipe to the joint body. FIG. 2 is a side view of a pipe fitting, partially in cross section, showing the condition after the pipe has been subjected to multiple tension and compression cycles. 11 is a cross-sectional view of a main portion of a tightening ring of another embodiment. FIG. 11 is a cross-sectional view of a main portion of a tightening ring of another embodiment. FIG. FIG. 13 is a side view of a pipe joint of a conventional example, with a portion in cross section showing a state in which a cap nut has been tightened to fix a pipe to a joint body. FIG. 13 is a side view of a conventional pipe joint, with a portion in cross section, showing the state after the pipe has been subjected to tension and compression multiple times.

Figure 1 shows the pipe fitting 1 of the present invention before a synthetic resin pipe is connected.

The pipe joint 1 comprises an inner core 2, a joint body 3, a tightening ring 4, and a cap nut 5.

The inner core 2 is made of metal and has a cylindrical portion 21 and an annular flange portion 22 extending radially outward from one end of the cylindrical portion 21. On the outer surface of the cylindrical portion 21, a plurality of teeth 21V with a sawtooth cross section that bite into the inner surface 6A of the tube 6 when a pulling force is applied to the tube 6 are continuously formed along the axial direction. These teeth 21V protrude more toward the flange portion 22. Therefore, the teeth 21V form a tapered outer surface 21B that expands the diameter of the end of the tube 6 when fitted inside the end of the tube 6. In addition, when the tube 6 is pulled, the teeth 21V bite into the inner surface 6A of the tube 6, preventing the tube 6 from coming out of the fitting body 3 (see FIG. 7).

The joint body 3 is made of metal and has a cylindrical first body part 31 that extends toward one axial end (left side in FIG. 1), and a cylindrical second body part 32 that extends toward the other axial end (right side in FIG. 1) and has larger inner and outer diameters than the first body part 31.

The outer surface of the first body 31 is formed with a male screw portion 31N for connecting other pipes, etc., by screwing. The end of the second body 32 is formed with a tapered inner surface 32A that is inclined in the opposite direction to the tapered outer surface 21B of the inner core 2 at an opening 32K into which the tube 6 can be inserted. In addition, the outer surface of the end of the second body 32 is formed with a male screw portion 32N (see FIG. 5) into which the female screw portion 51N of the cap nut 5 described later screws.

The tightening ring 4 is cylindrical and made of, for example, polyacetal (POM), and has a chamfered portion 41 with rounded corners on the outer surface of the leading edge 4T, a tapered outer surface 42 extending from the chamfered portion 41 in the opposite direction to the movement direction of the tightening ring 4, and a flat surface 43 extending parallel to the axial direction from the rear end of the tapered outer surface 42 to the rear. The tapered outer surface 42 has the same inclination direction and the same inclination angle as the tapered inner surface 32A of the joint body 3 (a different inclination angle is also acceptable). The tightening ring 4 may be made of various synthetic resins with rigidity other than polyacetal (POM), and may be made of any material that has equivalent rigidity.

2 and 3, the tightening ring 4 has a crest 44 located on the inner surface of the tightening ring 4, which is located on the inner diameter side of the inner diameter of the tip edge 4T, on the inner surface closer to the front edge 4T in the moving direction of the tightening ring 4. The tip edge 4T is an edge formed by the tip surface 4A of the tightening ring 4 and the inner surface (the imaginary inner side tapered surface 45 described later). The crest 44 is a bending point at the boundary between the imaginary inner side tapered surface 45 described later and the inner surface 46 described later. The imaginary inner side tapered surface 45 passing through the crest 44 and the tip edge 4T of the tightening ring 4 is approximately parallel to the tapered outer surface 21B of the inner core 2. The distance L1 between the crest 44 and the tip edge 4T of the tightening ring 4 is set to 20% or less, preferably 10% or less, of the total length L2 of the tightening ring 4. Specifically, the total length L2 of the tightening ring 4 is 25 mm, and the distance L1 between the crest 44 and the tip edge 4T of the tightening ring 4 is 2 mm. The angle of the tapered outer surface 21B of the inner core 2 with respect to the axial direction is the same as the angle θ of the tapered surface 45 with respect to the axial direction (see the enlarged view of FIG. 2), specifically, an arbitrary angle between 1 degree and 5 degrees. However, if the angle of the tapered outer surface 21B of the inner core 2 with respect to the axial direction is changed, it is preferable to change the angle θ of the imaginary inner circumference side tapered surface 45 with respect to the axial direction to the same angle or approximately the same angle as the angle of the tapered outer surface 21B. The position of the crest 44 of the tightening ring 4 is preferably changed depending on the size of the outer diameter of the tube 6, the material of the tube 6, etc.

The inner surface 46 of the tightening ring 4, which is located in front of the bent portion 44 in the direction of movement of the tightening ring 4 toward the tip of the tube 6, is configured as a straight surface parallel to the axial direction. The inner surface 46 of the tightening ring 4 is configured as a straight surface parallel to the axial direction, but it may also be configured as a straight surface approximately parallel to the axial direction. Approximately parallel to the axial direction includes a straight surface that is slightly inclined with respect to the axial direction. In addition, multiple (four) notches 4K are formed so as to extend in the axial direction at predetermined intervals (equally spaced) in the circumferential direction from approximately the center of the tightening ring 4 in the movement direction to the rear end opposite the movement direction (see FIG. 4). These multiple notches 4K may be omitted in some cases.

The cap nut 5 is made of metal, and the clamping ring 4 is moved toward the tip of the pipe 6 along the tapered inner surface 32A of the joint body 3 to press the inner surface of the clamping ring 4 against the outer surface of the pipe 6, thereby sealing between the pipe 6 and the clamping ring 4. Specifically, the cap nut 5 has a cylindrical portion 51 having a female screw portion 51N on the inside that screws into the male screw portion 32N of the second body portion 32, and an annular, plate-shaped inclined portion 52 that is inclined diagonally backward from the rear end of the cylindrical portion 51. By screwing the cap nut 5 into the male screw portion 32N of the second body portion 32, the inclined portion 52 can push the rear end surface 47 (see FIG. 4) of the clamping ring 4 to move the clamping ring 4 toward the end of the pipe 6.

The procedure for connecting the pipe 6 to the pipe fitting 1 configured as described above will now be explained.

First, the cap nut 5 is removed from the joint body 3, and the removed cap nut 5 is inserted onto the pipe 6. Next, the tightening ring 4 is removed from the joint body 3, and the removed tightening ring 4 is fitted onto the pipe 6. Next, the inner core 2 is pressed into the inside of the end of the pipe 6. After this, the end of the pipe 6 with the inner core 2 pressed into it is fitted into the joint body 3, and then the tightening ring 4 is fitted into the joint body 3, and the cap nut 5 is screwed onto the joint body 3. Next, by tightening the cap nut 5, the tightening ring 4 moves toward the tip side of the pipe 6, and the tapered outer surface 42 of the tightening ring 4 receives a pressing force from the tapered inner surface 32A of the joint body 3, so that the tightening ring 4 moves in the axial direction and gradually moves inward in the radial direction. As a result, the outer surface of the expanded pipe 6 and the inner surface of the tightening ring 4 are in close contact with each other, and the pipe 6 is fixed to the joint body 3 in a sealed state so that it cannot be removed (see FIG. 6).

After the pipe 6 is connected to the pipe fitting 1 as described above, when tension and compression are applied to the pipe 6 multiple times, the pipe 6 moves slightly in the direction of removal from the pipe fitting 1, as shown in Figure 7. This is because when the tightening ring 4 is tightened, the imaginary inner tapered surface 45 between the bent portion 44 and the leading edge 4T comes into contact with the surface (outer surface) 6B of the pipe 6, and the imaginary inner tapered surface 45 receives pressure in the direction of removal of the pipe 6. By dispersing this pressure at the imaginary inner tapered surface 45, it is possible to prevent the leading edge 4T from penetrating too far into the inner diameter side of the pipe 6, as shown in Figure 10, and causing the pipe 6 to be scraped.

The present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention.

In the above embodiment, the imaginary inner circumferential tapered surface 45 is formed between the crest 44 and the leading edge 4T, but as shown in FIG. 8, the crest 44 may be configured as a step 48 bent at 90 degrees. In this case, the crest 44, which is the corner of the leading edge 4T and the step 48, comes into contact with the outer surface of the tube 6 at two points. The step 48 may be provided not only at one location, but also at multiple locations in the axial direction. In this case, it is desirable to configure the multiple steps so that the step farther away from the leading edge 4T is located closer to the inner diameter side, and the straight line connecting the leading edge 4T and the corners of the multiple steps is approximately parallel to the tapered outer surface 21B of the inner core 2.

In the above embodiment, the leading edge 4T is formed at a right angle, but as shown in FIG. 9, it may be formed in a round shape without corners. In FIG. 9, the area between the leading edge 4T and the bent portion 44 is formed into a curved tapered surface 53 that is convex radially inward. This tapered surface 53 expands in diameter toward the leading edge 4T side. Note that the parts not described in FIG. 9 are given the same reference numerals as in FIG. 3, and description is omitted. Therefore, the area between the leading edge 4T and the bent portion 44 of the tightening ring 4 is formed into a linear tapered surface (reference numeral 45 in FIG. 3) that expands in diameter toward the leading edge side, or a curved tapered surface (reference numeral 53 in FIG. 9) that expands in diameter toward the leading edge side.

In addition, in the above embodiment, the cap nut 5 has an inclined portion 52, but it may also be configured with a vertical portion extending in the radial direction. In this case, the tightening ring 4 will have a shape with a vertical portion.

1...pipe fitting, 2...inner core, 3...fitting body, 4...tightening ring, 4A...tip surface, 4K...notch, 4T...tip edge, 5...cap nut, 6...pipe, 6A...inner surface, 6B...outer surface, 21...cylindrical portion, 21B...tapered outer surface, 21V...biting teeth, 22...flange portion, 31...first body portion, 32...second body portion, 31N...male thread portion, 32A...tapered inner surface, 32K...opening, 32N...male thread portion, 40...tightening ring, 40A...inner surface, 41...chamfered portion, 42...tapered outer surface, 43...flat surface, 44...ridged portion, 45...tapered surface, 46...inner surface, 47...rear end surface, 48...step portion, 48A...corner portion, 51...cylindrical portion, 51N...female thread portion, 52...inclined portion, 53...tapered surface, L1...distance, L2...total length, θ...angle

Claims (3)

a coupling body having a tapered inner surface at an opening into which the tube can be inserted and having a tapered inner surface that is inclined in an opposite direction to the tapered outer surface of the inner core; a tightening ring having a tapered outer surface that is inclined in the same direction as the tapered inner surface of the coupling body and that is fitted onto the tube; and a cap nut that reduces the diameter of the tube by moving the tightening ring along the tapered inner surface of the coupling body toward a tip end of the tube,
The tightening ring has a folded portion located on the inner surface proximal to the tip edge in the direction of movement of the tightening ring, the folded portion being located on the inner diameter side of the tip edge, and the area between the tip edge of the tightening ring and the folded portion is configured as a tapered surface that increases in diameter toward the tip . a coupling body having a tapered inner surface at an opening into which the tube can be inserted and having a tapered inner surface that is inclined in an opposite direction to the tapered outer surface of the inner core; a tightening ring having a tapered outer surface that is inclined in the same direction as the tapered inner surface of the coupling body and that is fitted onto the tube; and a cap nut that reduces the diameter of the tube by moving the tightening ring along the tapered inner surface of the coupling body toward a tip end of the tube,
the tightening ring has a folded portion located on the inner surface proximal to the leading edge in the direction of movement of the tightening ring, the folded portion being located on the inner diameter side of the leading edge, and a virtual inner circumference side tapered surface passing through the leading edge of the tightening ring and the folded portion is approximately parallel to the tapered outer surface of the inner core . 3. A pipe fitting according to claim 1, wherein an inner surface of the tightening ring on the side closer to the bent portion in a direction of movement of the tightening ring toward the tip of the pipe is configured as a straight surface that is approximately parallel to an axial direction of the tightening ring.