Water stop structure of pipe joint

Abstract

To provide a water-stopping structure for a pipe joint that can improve the versatility of parts without degrading water tightness. The rubber packing 3 includes an annular first rubber member 4 whose inner peripheral surface 41 contacts the outer peripheral surface 100a of the pipe 100, an annular second rubber member 5 laminated in the pipe diameter direction Y of the pipe 100 on the outer peripheral surface 42 of the first rubber member 4, and a lamination holding means 6 for holding the laminated state of the first rubber member 4 and the second rubber member 5. The first rubber member 4 is made of a rubber material harder than the second rubber member 5. In the laminated state of the first rubber member 4 and the second rubber member 5, the end portion 43 on the socket side of the first rubber member 4 protrudes in the pipe axis direction X of the pipe 100 more than the end portion 53 on the socket side of the second rubber member, and a part of the protruding portion 43a is disposed between the inner end portion 21a of the socket portion and the outer peripheral surface 100a of the pipe 100. The second rubber member 5 faces the tapered surface 21c of the socket portion 21.

Description

Technical Field

[0001] The present invention relates to a water stop structure for a pipe joint. More specifically, the present invention relates to a water stop structure for a pipe joint including a joint body having a receiving portion into which a pipe is inserted, an annular rubber packing attached to an outer peripheral surface of the pipe, and pressing means connected to the joint body for pressing the rubber packing against the receiving portion.

Background Art

[0002] Conventionally, as a water stop structure for a pipe joint as described above, for example, the one described in Patent Document 1 is known. In this water stop structure, for example, in the case of a pipe 100' to be inserted shown by a one-dot chain line in FIG. 9, in order to ensure watertightness, a rubber packing 3', a joint body 2', and a pressing ring 8' (pressing means 7') corresponding to the outer diameter of the pipe 100' are used. Therefore, in the case of a pipe 100'' having a smaller diameter than the pipe 100', these members cannot be used as they are, and a rubber packing, a joint body, and a pressing ring having an inner peripheral surface 31'', an inner end portion 21''a, and an inner end portion 81'' corresponding to the outer diameter of the smaller-diameter pipe 100'' are required. That is, each member must be prepared according to the outer diameter of the connecting pipe, and the pipe joint becomes expensive.

[0003] Therefore, it is conceivable to make the joint body 2' common and use, for example, a rubber packing 3'' as shown in FIG. 10. However, since the inner end portion 21'a of the inner side of the receiving portion 21' and the pipe 100'' are separated, the compressive force applied to the rubber packing 3'' escapes to the joint body 2' side, and the watertightness deteriorates. As shown in FIG. 9, even if only the rubber packing 3' is used with an increased wall thickness, the inner end portion 21'a is separated from the smaller-diameter pipe 100'', and the compression structure of the rubber packing 3' cannot be configured, so that watertightness cannot be ensured.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In view of such a conventional situation, an object of the present invention is to provide a water stop structure for a pipe joint that can improve the versatility of parts without reducing the watertightness.

Means for Solving the Problems

[0006] To achieve the above object, the water stop structure of a pipe joint according to the present invention is characterized in that it includes a joint body having a receiving portion into which a pipe is inserted, an annular rubber packing mounted on the outer peripheral surface of the pipe, and pressing means connected to the joint body for pressing the rubber packing against the receiving portion. In this configuration, the rubber packing has an annular first rubber member whose inner peripheral surface is in contact with the outer peripheral surface of the pipe, an annular second rubber member laminated in the pipe diameter direction on the outer peripheral surface of the first rubber member, and lamination holding means for holding the laminated state of the first rubber member and the second rubber member. The first rubber member is made of a rubber material harder than the second rubber member. In the laminated state of the first rubber member and the second rubber member, the end portion of the first rubber member on the receiving portion side protrudes in the pipe axis direction more than the end portion of the second rubber member on the receiving portion side, and a part of the protruding portion is disposed between the inner end portion of the receiving portion and the outer peripheral surface of the pipe. The end portion of the first rubber member on the pressing means side protrudes in the pipe axis direction more than the end portion of the second rubber member on the pressing means side, and a part of the protruding portion is disposed between the inner end portion of the pressing means and the outer peripheral surface of the pipe. And, one end portion of the second rubber member faces the tapered surface of the receiving portion, and the other end portion faces the pressing surface of the pressing means.

[0007] According to the above configuration, the rubber packing has an annular first rubber member whose inner peripheral surface is in contact with the outer peripheral surface of the pipe, an annular second rubber member laminated on the outer peripheral surface of the first rubber member in the pipe diameter direction, and a lamination holding means for holding the laminated state of the first rubber member and the second rubber member. Thereby, even when the outer diameter of the pipe is different, the second rubber member can be manufactured according to the shape of the joint body, and the first rubber member can be adjusted according to the outer diameter of the pipe. The joint body and the second rubber member can be made common, and the versatility can be improved. The first rubber member is made of a rubber material harder than the second rubber member. In the laminated state of the first rubber member and the second rubber member, the end portion of the first rubber member on the receiving port side protrudes more in the pipe axis direction of the pipe than the end portion of the second rubber member on the receiving port side, and a part of the protruding portion is disposed between the inner end portion of the receiving port and the outer peripheral surface of the pipe, and the second rubber member faces the tapered surface of the receiving port. Thereby, since a part of the protruding portion constitutes the compression structure of the second rubber member together with the tapered surface of the receiving port, the compression force by the pressing means does not escape into the joint body, and the second rubber member is compressed and deformed in the vicinity of the inner end portion to improve the watertightness.

[0009] Also, in the above configuration, annular ridges may be formed on the inner peripheral surface of the first rubber member at appropriate intervals along the pipe axis direction. When the ridges are compressed and deformed, the deformation and movement of the first rubber member in the pipe axis direction become smooth, and the watertightness at the outer peripheral surface of the pipe can be ensured.

[0010] On the other hand, in the above configuration, a lubricant may be applied to the inner peripheral surface of the first rubber member. Even in such a configuration, the deformation and movement of the first rubber member in the pipe axis direction become smooth, and the watertightness at the outer peripheral surface of the pipe can be ensured.

[0011] In the above configuration, the pressing means is a pressing ring that is mounted on the outer peripheral surface of the pipe and fastened to the joint body. In such a case, the rubber hardness of the second rubber member is 65° to 75°, and it is desirable that the rubber hardness of the first rubber member is 3° to 15° greater than that of the second rubber member. If the difference in rubber hardness exceeds 15°, the degree of compression deformation of the first and second rubber members will change significantly, and the laminated state of the first and second rubber members may not be maintained. On the other hand, if the difference in rubber hardness is less than 3°, the first rubber member is soft, so it is likely to deform in the pipe axis direction and the compressive force in the diameter-reducing direction will decrease. As a result, watertightness cannot be ensured.

[0012] On the other hand, in the above configuration, the pressing means is a union nut that is screwed and tightened on the outer peripheral surface of the receiving portion. In such a case, the rubber hardness of the second rubber member is 50° to 60°, and it is desirable that the rubber hardness of the first rubber member is 3° to 20° greater than that of the second rubber member. If the difference in rubber hardness exceeds 20°, the degree of compression deformation of the first and second rubber members will change significantly, and the laminated state of the first and second rubber members may not be maintained. On the other hand, if the difference in rubber hardness is less than 3°, the first rubber member is soft, so it is likely to deform in the pipe axis direction and the compressive force in the diameter-reducing direction will decrease. As a result, watertightness cannot be ensured.

[0013] In the above configuration, the lamination holding means may be composed of a plurality of recesses formed at appropriate intervals along the pipe axis direction on the outer peripheral surface of the first rubber member, and a plurality of protrusions formed at appropriate intervals along the pipe axis direction on the inner peripheral surface of the second rubber member. Thereby, the laminated state is maintained by the fitting of the unevenness.

[0014] In the above configuration, the outer peripheral portion of the end portion of the second rubber member on the receiving portion side has a tapered shape facing the tapered surface, and it is preferable that a plurality of annular ridges and annular grooves are alternately provided along the pipe axis direction on the outer peripheral portion. Thereby, the annular ridge is compressed and deformed, the entire second rubber member is reduced in diameter and adhered to the receiving portion, and stronger watertightness can be ensured.

Effect of the Invention

[0015] According to the characteristics of the water stop structure of the pipe joint according to the present invention, it is possible to improve the versatility of parts without reducing the watertightness.

[0016] Other objects, configurations, and effects of the present invention will become apparent from the following description of the embodiments of the invention.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

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Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Mode for Carrying Out the Invention

[0018] Next, with reference to FIGS. 1 to 4, the first embodiment of the present invention will be described in more detail. (Overall Outline of the First Embodiment) The water stop structure 1 of the pipe joint according to the first embodiment of the present invention, as shown in FIG. 1, generally includes a joint body 2 having a receiving portion 21 into which a pipe 100 is inserted, an annular rubber packing 3 attached to the outer peripheral surface 100a of the pipe 100 (hereinafter referred to as the "pipe outer surface"), and pressing means 7 connected to the joint body 2 for pressing the rubber packing 3 into the receiving portion 21. In the present embodiment, the pressing means 7 is constituted by a pressing ring 8.

[0019] (Joint body 2) As shown in FIGS. 1, 3, and 4, the joint body 2 generally has a tapered receiving portion 21 and a cavity 23 for positioning the pipe end portion of the pipe 100. An inner end portion 21a protruding toward the pipe axis side is provided at the end portion of the receiving portion 21 on the cavity 23 side. Further, a substantially rectangular flange 22 is formed on the outer peripheral portion 21b of the receiving portion 21, and a through hole 24 for inserting a T-head bolt 12a described later is formed at the corner portion 22a of the flange 22.

[0020] (Rubber packing 3) In the water stop structure 1 of the pipe joint according to the present invention, the rubber packing 3 includes an annular first rubber member 4 whose inner peripheral surface 41 is in contact with the pipe outer periphery 100a, an annular second rubber member 5 laminated in the pipe diameter direction Y on the outer peripheral surface 42 of the first rubber member 4, and lamination holding means 6 for holding the laminated state of the first rubber member 4 and the second rubber member 5 laminated in the pipe diameter direction Y.

[0021] In the present invention, the first rubber member 4 is made of a rubber material harder than the second rubber member 5. And in the present embodiment, for example, the rubber hardness of the second rubber member 5 is 65° to 75° (70° ± 5°), and the rubber hardness of the first rubber member 4 is 3° to 15° greater than the rubber hardness of the second rubber member 5.

[0022] (First rubber member 4) As shown in FIG. 2, a plurality of annular ridges 41a are formed at appropriate intervals along the pipe axis direction X on the inner peripheral surface 41 of the first rubber member 4. Further, a plurality of recesses 42a are formed at appropriate intervals along the pipe axis direction X on the outer peripheral surface 42 of the first rubber member 4. The ridges 41a and the recesses 42a are formed at the central portion in the width direction of the main body portion 40 of the first rubber member 4. In the present embodiment, the ridges 41a and the recesses 42a are not formed in the vicinity of the first end portion 43 which is the end portion on the receiving port portion 21 side and the second end portion 44 which is the end portion on the pressing ring 8 (pressing means 7) side. Further, in the present embodiment, the rubber hardness of the first rubber member 4 is, for example, 73° to 85°. In particular, if the hardness of the first rubber member 4 is softer than this, in the case of FIG. 4 described later, the rubber protrudes (flows) in the pipe axis direction and it is difficult to maintain the compressive force of the rubber, so that the watertightness cannot be maintained.

[0023] Here, the inner diameter of the first rubber member 4 is larger than the outer diameter of the pipe 100. Thus, as shown in FIG. 3, it can be temporarily fixed (temporarily assembled) using the spacer 56. Further, the outer diameter of the recess 42a portion of the outer peripheral surface 42 of the first rubber member 4 (hereinafter referred to as the "outer diameter of the first rubber member 4") is slightly larger than the inner diameter of the convex portion 51a portion of the inner peripheral surface 51 of the second rubber member 5 (hereinafter referred to as the "inner diameter of the second rubber member 4"). Thereby, when laminating, the first rubber member 4 has to be reduced in diameter, and the repulsive force of the rubber due to this diameter reduction makes it difficult to come off. Note that "slightly larger" means, for example, a dimension that is 1 to 3% larger than the inner diameter of the second rubber member 5 with respect to the outer diameter of the first rubber member 4. In the present embodiment, the ridges 41a and the recesses 42a are formed on the same straight line (concentric with the pipe axis) along the pipe diameter direction Y on the front and back of the main body portion 40.

[0024] (Second rubber member 5) As shown in FIGS. 3 and 4, a plurality of annular convex portions 51a are formed on the inner peripheral surface 51 of the second rubber member 5 at appropriate intervals along the pipe axis direction X. Further, a tapered surface 59 that faces the tapered surface 21c of the receiving port portion 21 is formed on the outer peripheral portion of the first end portion 53 that is the end portion on the receiving port portion 21 side of the second rubber member 5. A plurality of annular convex ridges 58a and annular concave ridges 58b are alternately provided on this tapered surface 59 along the pipe axis direction X. On the other hand, the second end portion 54 that is the end portion on the pressing ring 8 (pressing means 7) side abuts against the pressing surface 82 of the pressing ring 8. Note that positioning ribs 55 are provided on the outer peripheral surface 52 of the second rubber member 5.

[0025] (Laminating and holding means 6) In the present embodiment, the laminating and holding means 6 includes the concave portion 42a of the first rubber member 4 and the convex portion 51a of the second rubber member 5. By fitting these uneven portions, the laminated state of the first rubber member 4 and the second rubber member 5 is firmly held.

[0026] Here, in the laminated state of the first rubber member 4 and the second rubber member 5 shown in FIGS. 3 and 4, the first end portion 43 of the first rubber member 4 protrudes in the pipe axis direction X more than the first end portion 53 of the second rubber member 5. And a part (tip) 43a of the protruding portion is disposed between the inner end portion 21a and the outer pipe surface 100a. Further, in the present embodiment, the second end portion 44 of the first rubber member 4 protrudes in the pipe axis direction X more than the second end portion 54 of the second rubber member 5. And a part (tip) 44a of the protruding portion is disposed between the inner end portion 81 of the pressing ring 8 and the outer pipe surface 100a. Note that the protrusion 41a and the convex portion 42a are formed on the same straight line (concentric with the pipe axis) along the pipe diameter direction Y.

[0027] (Pressing means 7, pressing ring 8) In this embodiment, the pressing means 7 is a pressing ring 8 that is mounted on the outer surface 100a of the pipe and fastened to the joint body 2. As shown in FIGS. 1, 3, and 4, the pressing ring 8 has a ring-shaped main body portion 80 that generally covers the outer surface 100a of the pipe, an inner end portion 81 that protrudes from the main body portion 80 toward the pipe axis side, and a pressing surface 82 that presses the second rubber member 5. Further, a through hole 84 through which a T-head bolt 12a fastened to the joint body 2 passes is provided in the flange portion 83 of the main body portion 80.

[0028] (Construction Procedure) Here, with reference to FIGS. 3 and 4, the construction procedure of the pipe joint will be described. First, the second rubber member 5 is laminated on the outer peripheral surface 42 of the first rubber member 4. At this time, the convex portion 51a of the second rubber member 5 is fitted into the concave portion 42a of the first rubber member 4. As described above, since the outer diameter of the first rubber member 4 is slightly larger than the inner diameter of the second rubber member 5, the fitting of the unevenness becomes more difficult to come off due to the repulsive force of the rubber caused by the reduction in the diameter of the first rubber member 4 when laminating. Moreover, the first rubber member 4 is harder than the second rubber member 5, and the rubber hardness of the first rubber member 4 is 3 to 15° greater than the rubber hardness of the second rubber member 5. Within this hardness difference range, the fitting of the unevenness is difficult to come off even during the compression deformation described later, and the laminated state is maintained. Then, the laminated first and second rubber members 4 and 5 are mounted on the socket portion 21.

[0029] As described above, since the inner diameter of the first rubber member 4 is larger than the outer diameter of the pipe 100, as shown in FIG. 3, the pressing surface 82 of the pressing ring 8 is brought into contact with the second end portion 54 of the second rubber member 5, and a spacer 56 is sandwiched between the flange 22 of the socket portion 21 on which the first and second rubber members 4 and 5 are mounted and the flange 83 of the pressing ring 8, and the T-head bolt 12a and the nut 12b are tightened to form a temporary assembly state. Thereby, the second rubber member 5 is not pushed in during transportation to the construction site or the like. Further, since the inner diameter of the first rubber member 4 is larger than the outer diameter of the pipe 100, the pipe 100 can be easily inserted in the temporary assembly state as shown in the figure, and the workability is excellent.

[0030] Then, as shown in FIG. 4, the spacer 56 is removed and the T-head bolt 12a and the nut 12b are tightened. In the present embodiment, since a part 44a of the protruding portion is disposed between the inner end portion 81 and the outer surface 100a of the pipe, the pressing force by the pressing ring 8 acts on the second rubber member 5 by the pressing surface 82. Then, due to the pressing force, the outer peripheral portion of the second rubber member 5 abuts on the tapered surface 21c of the receiving portion 21 and deforms.

[0031] Here, the first end portion 43 of the first rubber member 4 protrudes in the pipe axis direction X more than the first end portion 53 of the second rubber member 5, and a part 43a of the protruding portion is disposed between the inner end portion 21a and the outer surface 100a of the pipe. The first rubber member 4 is made of a rubber material harder than the second rubber member 5. Therefore, a part 43a of the protruding portion constitutes a compression structure of the first end portion 53 of the second rubber member 5 together with the tapered surface 21c. As a result, the convex stripe 58a is compressed and deformed by the tapered surface 21c, and the entire second rubber member 5 moves toward the inner end portion 21a side along the tapered surface 21c and the diameter is reduced. When further pressed, the second rubber member 5 rolls along the tapered surface 21c and further reduces the diameter, and the tapered outer peripheral portion 59 closely adheres to the tapered surface 21c to improve the watertightness.

[0032] Furthermore, due to the compression deformation of the second rubber member 5, the first rubber member 4 is pressed against the outer surface 100a of the pipe. Here, since the first rubber member 4 is a rubber material harder than the second rubber member 5, although it is difficult to deform in the pipe axis direction, it is easily compressed and reduced in diameter in the pipe diameter direction. As shown in FIG. 4, the central portion in the width direction of the main body portion 40 in which the concave portion 42a is formed is mainly compressed and deformed. Then, the protruding stripe 41a is compressed and deformed, and the inner peripheral surface 41 closely adheres to the outer surface 100a of the pipe. Since the protruding stripe 41a is provided on the inner peripheral surface 41, the compression deformation of the protruding stripe 41a facilitates the deformation and movement of the first rubber member 4 in the pipe axis direction. Therefore, following the rolling and diameter reduction of the second rubber member 5, the first rubber member 4 also moves and reduces the diameter in the pipe axis direction, so that the watertightness at the outer surface 100a of the pipe can be ensured. (Overall Outline of the Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIGS. 5 to 7. In the following embodiments, the same members as those in the above embodiments are denoted by the same reference numerals.

[0033] (Pressing means 7, union nut 9) In the above first embodiment, the pressing means 7 was the pressing ring 8, but in the second embodiment, the pressing means 7 is a union nut 9 that is screwed and tightened to the outer peripheral surface 21b of the receiving portion 21.

[0034] As shown in FIGS. 5 to 7, this union nut 9 generally has an inner end portion 91 that protrudes toward the tube axis side and a pressing surface 92 that presses the second rubber member 5. Further, an internal thread 93 that engages with an external thread 25 of a receiving portion 21 described later is formed on the inner peripheral surface 90a of the union nut 9, and an annular groove portion 94 that engages with a main body portion 11a of a locking tool 11 described later is provided on the outer peripheral surface 90b. In the present embodiment, the inner end portion 91 is located inside the groove portion 94. And this union nut 9 is used together with a retaining ring 10 that is attached to the outer tube surface 100a and tightened by a tightening means 13, and a locking tool 11 that is detachably attached to the groove portion 94 of the union nut 9 and holds the connection with the retaining ring 10.

[0035] In the second embodiment, for example, the rubber hardness of the second rubber member 5 is 50° to 60° (55° ± 5°), and the rubber hardness of the first rubber member 4 is 3° to 20° greater than the rubber hardness of the second rubber member 5. Note that the first and second rubber members 4 and 5 and the laminated holding means 6 have the same basic configuration as in the above first embodiment although their dimensions and the like are different, so the description thereof is omitted. In the present embodiment, the rubber hardness of the first rubber member 4 is, for example, 58° to 75°.

[0036] (Joint body 2) As shown in FIGS. 5 to 7, in the second embodiment, the joint body 2 is provided with an external thread 25 engraved on its outer peripheral surface 21b. The external thread 25 engages with an internal thread 93 engraved on the inner peripheral surface 90a of the union nut 9. By screwing and tightening the union nut 9 to the receiving portion 21, the first and second rubber members 4 and 5 are compressed and deformed.

[0037] (Retaining ring 10) As shown in FIGS. 5 to 7, the wheel stopper 10 generally has a main body portion 10a in the shape of a C-ring, and a pair of protruding pieces 10b, 10b that protrude outward from both ends of the main body portion 10a. A through hole 10c for inserting the bolt 13a of the fastening means 13 is provided in the protruding piece 10b. In the present embodiment, a pair of receiving portions 10d, 10d for receiving the hook portions 11c of the locking tool 11 described later are provided on the outer peripheral surface of the main body portion 10a. Further, an annular tooth portion 10e for suppressing the sliding of the pipe 100 is formed on the inner surface of the main body portion 10a.

[0038] (Locking tool 11) As shown in FIGS. 5 to 7, the locking tool 11 generally has a main body portion 11a in the shape of a horseshoe, a pair of arm portions 11b, 11b that extend along the pipe axis direction X from both end portions of the main body portion 11a, and hook portions 11c that protrude toward the center at the end portions of the pair of arm portions 11b, 11b.

[0039] (Construction procedure) Here, with reference to FIGS. 6 and 7, the construction procedure of the union nut pipe joint will be described. First, the second rubber member 5 is laminated on the outer peripheral surface 42 of the first rubber member 4. Since this is the same as the above-described embodiment, the uneven fitting is difficult to come off even during compression deformation, and the laminated state is maintained. As shown in FIG. 6, the wheel stopper 10 is attached to the outer surface 100a of the pipe, and the union nut 9 is screwed onto the joint body 2 with the first and second rubber members 4 and 5 in the laminated state interposed in the receiving portion 21. Then, the main body portion 10a of the locking portion 11 is engaged with the groove portion 94 of the union nut 9, and the hook portion 10c is locked to the receiving portion 10d of the wheel stopper 10.

[0040] Then, as shown in FIG. 7, the union nut 9 is tightened. Also in the second embodiment, since a part 44a of the protruding portion is disposed between the inner end portion 91 and the outer surface 100a of the pipe, the pressing force by the union nut 9 acts on the second rubber member 5 by the pressing surface 92. Then, the outer peripheral portion of the second rubber member 5 abuts against the tapered surface 21c of the receiving portion 21 and deforms by the pressing force.

[0041] Also, in the second embodiment as well, a part 43a of the protruding portion is disposed between the inner end 21a and the outer surface 100a of the tube, and the first rubber member 4 is made of a rubber material harder than the second rubber member 5. Therefore, also in the second embodiment, the ridge 58a is compressed and deformed by the tapered surface 21c, and the entire second rubber member 5 moves toward the inner end 21a side along the tapered surface 21c and the diameter is reduced. When further pressed, the second rubber member 5 rolls along the tapered surface 21c and the diameter is further reduced, and the tapered outer peripheral portion 59 comes into close contact with the tapered surface 21c to improve the watertightness.

[0042] Furthermore, since the configuration of the first rubber member 4 is the same as that in the above embodiment, the first rubber member 4 also moves and the diameter is reduced in the tube axis direction following the rolling and diameter reduction of the second rubber member 5. Therefore, also in the second embodiment, the watertightness at the outer surface 100a of the tube can be ensured.

[0043] (Other Embodiments) Finally, the possibility of still other embodiments of the present invention will be described. In the above first embodiment, in the laminated state of the first rubber member 4 and the second rubber member 5, the second end portion 44 of the first rubber member 4 is made to project in the pipe axis direction X more than the second end portion 54 of the second rubber member 5, and a part 54a of the projecting portion is disposed between the inner end portion 81 of the pressing ring 8 (pressing means 7) and the outer peripheral surface 100a of the pipe 100. However, as shown in FIG. 8, the second end portion 44 of the first rubber member 4 may be disposed at the same position as the second end portion 54 of the second rubber member 5 and opposed to the pressing surface 82 of the pressing ring 8. This also applies to the second embodiment, and the second end portions 44 and 54 may be disposed at the same position and opposed to the pressing surface 92 of the union nut 9. In the present invention, it is only necessary to be able to form the compression structure of the second rubber member 5 in the receiving portion 21. At least, the first end portion 43 of the first rubber member 4 projects in the pipe axis direction X more than the first end portion 53 of the second rubber member 5, and a part 43a of the projecting portion is disposed between the inner end portion 21a of the receiving portion 21 and the outer peripheral surface 100a of the pipe 100. In the case of FIG. 8, the rubber hardness of the first rubber member 4 is, for example, 70° to 85°. Different from FIG. 4 of the above first embodiment, in FIG. 8, the deformation (protrusion) of the first rubber member 4 in the pipe axis direction is suppressed by the pressing surface 82 of the pressing ring 8, and thus, if it is within the above numerical range, the watertightness is maintained.

[0044] In the above first and second embodiments, a plurality of annular ridges 41a are formed on the inner peripheral surface 41 of the first rubber member 4 at appropriate intervals along the pipe axis direction X. However, these ridges 41a may be omitted, and instead, a lubricant may be applied to the inner peripheral surface 41. When these ridges 41a are omitted, the inner peripheral surface 41 of the first rubber member 4 comes into close contact with the outer peripheral surface 100a of the pipe 100 due to the compression deformation of the second rubber member 5. Therefore, the first rubber member 4 follows the compression deformation of the second rubber member 5 and cannot be deformed or moved in the pipe axis direction, and watertightness cannot be ensured. By applying a lubricant, the deformation and movement of the first rubber member 4 in the pipe axis direction X become easy, and watertightness can be ensured. Thus, it is only necessary to be able to reduce the resistance at the contact surface between the first rubber member 4 and the pipe 100, and the first rubber member 4 may be formed of a highly lubricious rubber material.

[0045] In the above first and second embodiments, the lamination holding means 6 is constituted by the concave portion 42a on the outer peripheral surface 42 of the first rubber member 4 and the convex portion 51a on the inner peripheral surface 51 of the second rubber member 5. However, the lamination holding means 6 is not limited to this. For example, a convex portion may be formed on the first rubber member 4 and a concave portion may be formed on the second rubber member 5, and these may also be used as the lamination holding means 6. The dimensions, shapes, numbers, etc. of the concave portion 42a and the convex portion 51a may be appropriately set in a manner capable of maintaining the laminated state.

[0046] Also, in the above first and second embodiments, the ridge 41a on the inner peripheral surface 41 of the first rubber member 4 and the concave portion 42a on the outer peripheral surface 42 are located on the same straight line along the pipe diameter direction, and the shape of the ridge 41a is also similar to that of the convex portion 51a. However, the dimensions, shapes, numbers, etc. of the ridge 41a may also be appropriately set. For example, the height and width of the ridge 41a are made smaller than those of the concave portion 42a and the convex portion 51a, and the number is also made smaller than that of the concave portion 42a. Thereby, it becomes easier to take out from the mold when the first rubber member 4 is rubber-molded. Also, the ridge 41a may be formed not only at the center in the width direction of the main body portion 40 but also from the first end portion 43 on the receiving port portion 21 side to the second end portion 44 on the pressing means 7 side (on the entire inner peripheral surface 41).

[0047] In the above second embodiment, the pressing means 7 is constituted by the union nut 9, the retaining ring 10, and the locking tool 11. The retaining ring 10 and the locking tool 11 are not limited to those of the second embodiment as long as they function as a union nut pipe joint.

Explanation of Reference Numerals

[0048] 1, 1’, 1’’: Water stop structure, 2, 2’: Joint body, 3, 3’, 3’’’: Rubber packing, 4: First rubber member, 5: Second rubber member, 6: Laminated holding means, 7, 7’, 7’’: Pressing means, 8, 8’, 8’’: Pressing wheel, 9: Union nut, 10: Stop ring, 10a: Body part, 10b: Projection, 10c: Through hole, 10d: Receiving part, 10e: Tooth part, 11: Locking tool, 11a: Body part, 11b: Arm part, 11c: Hook part, 12a: T-head bolt, 12b: Nut, 13: Tightening means, 13a: Bolt, 13b: Nut, 21, 21’: Receiving port part, 21a, 21’a: Inner end part, 21b: Outer peripheral part, 21c: Tapered surface, 22: Flange, 22a: Corner part, 23: Cavity, 24: Through hole, 25: Male thread, 31’, 31’’, 31’’’: Inner peripheral surface, 40: Body part, 41: Inner peripheral surface, 41a: Ridge, 42: Outer peripheral surface, 42a: Recess, 43: First end part (end part on the receiving port side), 43a: Part of the protruding part (tip), 44: Second end part (end part on the pressing means side), 51: Inner peripheral surface, 51a: Protrusion, 52: Outer peripheral surface, 53: First end part (end part on the receiving port side), 54: Second end part (end part on the pressing means side), 55: Positioning rib, 56: Spacer, 58a: Ridge, 58b: Groove, 59: Tapered surface (outer peripheral part of the first end part), 80: Body part, 81, 81’, 81’’: Inner end part, 82, 82’, 82’’: Pressing surface, 83: Flange, 84: Through hole, 90a: Inner peripheral surface, 90b: Outer peripheral surface, 91: Inner end part, 92: Pressing surface, 93: Female thread, 94: Groove part, 100, 100’, 100’’: Pipe, 100a: Outer peripheral surface (outer surface of the pipe), X: Pipe axis direction, Y: Pipe diameter direction

Claims

1. A watertight structure for a pipe joint comprising a joint body having a socket portion into which a pipe is inserted, an annular rubber packing attached to an outer peripheral surface of the pipe, and a pressing means connected to the joint body for pressing the rubber packing against the socket portion, the rubber packing includes an annular first rubber member whose inner peripheral surface is in contact with an outer peripheral surface of the pipe, an annular second rubber member laminated on the outer peripheral surface of the first rubber member in a radial direction of the pipe, and a layering maintaining means for maintaining a layered state of the first rubber member and the second rubber member, The first rubber member is made of a rubber material harder than the second rubber member, In a laminated state of the first rubber member and the second rubber member, an end portion of the first rubber member on the side of the receiving port protrudes in a pipe axial direction of the pipe further than an end portion of the second rubber member on the side of the receiving port, and a part of the protruding portion is disposed between an inner end portion of the receiving port and an outer peripheral surface of the pipe, an end of the first rubber member on the pressing means side protrudes in the tube axial direction further than an end of the second rubber member on the pressing means side, and a part of the protruding portion is disposed between an inner end of the pressing means and an outer peripheral surface of the tube; and The second rubber member has one end facing the tapered surface of the receiving portion and the other end facing the pressing surface of the pressing means.

2. 2. A waterproof structure for a pipe joint according to claim 1, wherein annular ridges are formed on an inner peripheral surface of said first rubber member at appropriate intervals along the axial direction of said pipe.

3. 2. The waterproof structure of a pipe joint according to claim 1, wherein an inner peripheral surface of the first rubber member is coated with a lubricant.

4. 2. A watertight structure for a pipe joint according to claim 1, wherein said pressing means is a pressing ring attached to an outer circumferential surface of said pipe and fastened to said joint body.

5. 5. A waterproof structure for a pipe joint according to claim 4, wherein the rubber hardness of the second rubber member is 65° to 75°, and the rubber hardness of the first rubber member is 3° to 15° greater than the rubber hardness of the second rubber member.

6. 2. A watertight structure for a pipe joint according to claim 1, wherein said pressing means is a union nut screwed tightly onto an outer circumferential surface of said socket portion.

7. 7. A waterproof structure for a pipe joint according to claim 6, wherein the rubber hardness of the second rubber member is 50° to 60°, and the rubber hardness of the first rubber member is 3° to 20° greater than the rubber hardness of the second rubber member.

8. 2. The water-stopping structure of a pipe joint as described in claim 1, wherein the laminated retaining means comprises a plurality of recesses formed at appropriate intervals along the pipe axial direction on the outer peripheral surface of the first rubber member, and a plurality of protrusions formed at appropriate intervals along the pipe axial direction on the inner peripheral surface of the second rubber member.

9. 2. A water-stopping structure for a pipe fitting as described in claim 1, wherein an outer periphery of the end portion of the second rubber member on the receiving portion side is tapered facing the tapered surface, and a plurality of annular convex ridges and annular concave ridges are alternately provided on the outer periphery along the pipe axial direction.

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