JP4764611B2 - Displacement absorption joint - Google Patents

Description

  The present invention relates to a displacement absorbing joint used for gas piping and the like.

  As this type of displacement absorbing joint, there are those shown in FIGS. 4 and 5 (see, for example, Patent Document 1). This displacement absorbing joint includes an outer cylindrical tube 1 and an inner cylindrical tube 2 that are slidably fitted to each other in the axial direction, and the outer cylindrical tube 1 and the inner cylindrical tube 2 are respectively connected to the outer ends of the tubes. Ball joint mechanisms 5 and 6 having connection ports 3 and 4 are provided. These ball joint mechanisms 5 and 6 have spherical sliding surfaces 7 and 8, respectively, and the pipe connection port portions 3 and 4 are connected to the outer cylindrical tube 1 and the inner cylindrical tube 2 by the sliding action on the sliding surfaces 7 and 8. It is possible to make angular displacement within a certain range with respect to the axis of. Therefore, according to this joint, a pipe (not shown) connected to the pipe connection port 3 of one ball joint mechanism 5 and a pipe connected to the pipe connection port 4 of the other ball joint mechanism 6 (see FIG. (Not shown) can be connected with a certain bending angle. And the displacement in the perspective direction of the pipe | tube connected to the pipe connection port part 3 of one ball joint mechanism 5 and the pipe connected to the pipe connection port part 4 of the other ball joint mechanism 6 at the time of an earthquake etc. is the following. It is absorbed by the expansion and contraction action between the outer tube 1 and the inner tube 2.

  Further, a female screw 9a at one end of a slide housing 9 fitted on the inner cylindrical tube 2 is screwed into the male screw 1a at the inner end of the outer cylindrical tube 1, and is connected to the inner periphery of the other end of the slide housing 9. Annular first and second concave grooves 10 and 11 are provided side by side in the axial direction, and a slide ring 12 slidable with respect to the outer peripheral surface of the inner tube 2 is formed in the second concave groove 11. The waterproof packings 13 that are slidably adhered to the outer peripheral surface of the inner tube 2 in a watertight state are fitted and held. That is, the slide ring 12 and the waterproof packing 13 are held inside and outside in the axial direction on the inner periphery of the other end of the slide housing 9, thereby allowing rainwater and foreign matter to pass between the inner tube 2 and the outer tube 1 in the outdoor piping. A waterproof seal function that prevents entry into the camera is exhibited.

  On the other hand, annular third, fourth, fifth, and sixth concave grooves 14, 15, 16, and 17 are provided on the outer periphery of the inner end portion of the inner tube 2 at predetermined intervals inside and outside in the axial direction. 14, a slide ring 18 slidable with respect to the inner peripheral surface of the outer cylindrical tube 1 is slidable in close contact with the inner peripheral surface of the outer cylindrical tube 1 in the fourth concave groove 15. In the seal ring 19, the second airtight seal ring 20 is fitted and held in the sixth concave groove 17. That is, the slide ring 18 and the first and second airtight seal rings 19 and 20 are held side by side in the axial direction on the outer periphery of the inner end portion of the inner cylindrical tube 2, thereby allowing gas or other fluid in the pipe to flow inside the inner cylindrical tube. An airtight sealing function for preventing leakage from the gap between the outer tube 1 and the outer tube 1 is exhibited. In addition, a fireproof packing 21 is fitted and held in the fifth concave groove 16, and a flame enters the gap between the inner tube 2 and the outer tube 1 when a fire breaks out, and is disposed inside the first airtight. The seal ring 19 is prevented from being exposed to a flame.

JP-A-11-287370

  However, recently, there has been a demand for increasing the length of the displacement absorbing joint for use in a base-isolated building. However, in the displacement absorbing joint having the above structure, if the outer cylindrical tube 1 and the inner cylindrical tube 2 are simply elongated in the structure, the inner and outer cylindrical tubes 2 and 1 are bent by their own weight when they are extended. The cylindrical tubes 2 and 1 are in a folded state, and this increases the frictional force between the slide ring 12 and the inner cylindrical tube 2 in the slide housing 9, and the outer peripheral surface of the inner cylindrical tube 2 is scratched. Reduces slidability. In particular, since it is necessary to follow a large acceleration displacement such as an earthquake, a decrease in slidability is a major bottleneck. Further, the scratches on the outer peripheral surface of the inner cylinder tube 2 cause deterioration of the waterproof sealability and corrosion of the inner cylinder tube 2.

  The present invention has been made to solve such a problem, and the object of the present invention is to make the waterproof seal portion and the airtight seal portion between the inner tube and the outer tube by improving the length. To provide a displacement-absorbing joint that eliminates problems, i.e., the rubbing phenomenon in the inner tube, is excellent in slidability, and can improve sealing performance in order to better follow large accelerations such as earthquakes. It is in.

In the present invention, the inner end of the inner tube (2) is slidably inserted in the inner end of the outer tube (1) in the axial direction, and the inner end of the outer tube (1) is inserted into the inner end of the outer tube (1). One end portion of the slide housing (9) externally fitted to the cylindrical tube (2) is screwed and coupled, and a slide ring (12) and an inner cylindrical tube (2) are connected to the inner periphery of the other end portion of the slide housing (9). A waterproof packing (13) that is slidably in close contact with the outer peripheral surface of the outer cylindrical tube is held side by side in the axial direction, and is disposed on the outer periphery of the inner end of the inner cylindrical tube (2). A slide ring (18) that holds the inner cylinder pipe (2) so as to be slidable with respect to the inner peripheral surface and is fitted and held in a concave groove provided on the outer periphery of the inner cylinder pipe (2); and an outer cylinder pipe (1 The first and second airtight seal rings (19) and (20) that can slide in close contact with the inner peripheral surface of In the displacement-absorbing joint that is held all the way, the slide ring (12) on the inner periphery of the other end of the slide housing (9) is in a non-contact state with the outer peripheral surface of the inner tube (2) in a normal state. A waterproof packing (23) that is slidably in close contact with the outer peripheral surface of the inner tube (2) in a watertight state is arranged inside the slide ring (12) on the inner periphery of the slide housing (9). It is held and is slidable with respect to the inner peripheral surface of the outer cylindrical pipe (1) on the outer side in the axial direction of the second airtight seal ring (20) on the outer periphery of the inner end of the inner cylindrical pipe (2). The slide ring (25) that holds the inner tube (2) is fitted and held side by side.

  As one suitable aspect, the displacement absorption joint by this invention can give hard chrome plating (26) to the inner surface of an outer cylinder pipe (1). Moreover, the outer cylindrical pipe (1) and the inner cylindrical pipe (2) have spherical sliding surfaces (7) and (8) at the outer end portions of the outer cylindrical pipe (1) and the pipe connecting ports (3) and (4), respectively. Ball joint mechanisms (5) and (6) can be provided.

  According to the displacement absorbing joint having the above-described configuration, the waterproof seal portion in the slide housing is provided with the waterproof packing not only in the axial direction outside of the slide ring but also in the axial direction so that the inner cylinder can be sealed with the waterproof packing inside and outside in the normal state. Since the holding force of the tube is strengthened and the slide ring can be brought into a non-contact state with respect to the outer peripheral surface of the inner tube, the frictional force between the slide ring and the inner tube can be reduced. This can prevent the inner tube from rubbing. The slide ring exhibits the function of holding the inner tube only when the waterproof packing cannot hold it due to external stress.

  In the hermetic seal portion at the inner end of the inner tube, a slide ring is provided not only in the axial direction inside of the first hermetic seal ring but also in the axial direction outside of the second hermetic seal ring. By holding the inner tube, it is possible to reduce the deflection (inclination) of the inner tube due to its own weight or external stress when the inner and outer tube are extended. By reducing the deflection of the inner cylinder tube, it is possible to further reduce the frictional force between the slide ring and the inner cylinder tube, and to prevent the inner cylinder tube from being scratched.

  The waterproof packing is provided not only in the axial direction outside of the slide ring in the slide housing but also in the axial direction, and not only in the axial direction inside of the first airtight seal ring on the outer periphery of the inner end of the inner tube. Due to the synergistic effect of providing the slide ring on the outer side in the axial direction of the second airtight seal ring, the effect of preventing the rubbing of the elongated inner tube and the improvement of the slidability can be enhanced. In particular, since it is excellent in slidability, it well follows large accelerations such as earthquakes and is suitable as a displacement absorbing joint for base-isolated buildings.

  If hard chrome plating is applied to the inner surface of the outer tube, the hard chrome plating will not peel off even if it is rubbed against the slide ring, and it is possible to prevent the inner surface of the outer tube from being rubbed and scratched. In addition, hard chrome plating is easier to process on the inner surface of a long outer tube than colored chromate.

  A preferred embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a side view of a displacement absorbing joint according to an embodiment, FIG. 2 is an enlarged cross-sectional view of the essential part of the displacement absorbing joint of FIG. 1, and FIG. 3 is an enlarged view of the essential part of FIG. It is a fragmentary sectional view shown.

  In FIG. 1, the displacement absorbing joint includes an outer cylindrical tube 1 and an inner cylindrical tube 2 that are slidably fitted in an axial direction, and the outer end of each of the outer cylindrical tube 1 and the inner cylindrical tube 2. Are provided with ball joint mechanisms 5 and 6 having pipe connection ports 3 and 4, and these ball joint mechanisms 5 and 6 have spherical sliding surfaces 7 and 8, respectively. With respect to the fact that the pipe connection ports 3 and 4 can be angularly displaced within a certain range with respect to the axis of the outer tube 1 or the inner tube 2 by the sliding action on the surfaces 7 and 8, FIG. The same reference numerals are given to the same members, and the duplicate description is omitted.

  As shown in FIGS. 1 and 2, a female screw 9a at one end of a slide housing 9 fitted on the inner cylindrical tube 2 is screwed into a male screw 1a at the inner end of the outer cylindrical tube 1, and the slide Annular first and second concave grooves 10 and 11 are provided on the inner periphery of the other end of the housing 9 so as to be arranged at predetermined intervals in the axial direction, and a slide ring 12 is provided in the first concave groove 10 and the second concave groove. 11, the waterproof packing 13 that is slidably in close contact with the outer peripheral surface of the inner tube 2 in a watertight manner is fitted and held, so that rainwater or the like can flow between the inner tube 2 and the outer tube 1 in outdoor piping. A waterproof seal is provided to prevent intrusion into the tube, and annular third, fourth, fifth, sixth recesses 14, 15, 16, and 17 are formed on the outer periphery of the inner end of the inner tube 2. The third concave groove is arranged in order from the inner side in the axial direction to the outer side in the axial direction at predetermined intervals. 4, a slide ring 18 slidable with respect to the inner peripheral surface of the outer cylindrical tube 1 is slidable in close contact with the inner peripheral surface of the outer cylindrical tube 1 in the fourth concave groove 15. When the seal ring 19 is fitted and held in the sixth concave groove 17 with the second airtight seal ring 20, fluid such as gas in the pipe leaks from the gap between the inner tube 2 and the outer tube 1. In addition, an airtight seal is provided to prevent this, and a fireproof packing 21 is arranged between the first airtight seal ring 19 and the second airtight seal ring 20 with respect to the inner peripheral surface of the outer tube 1. The holding is the same as described with reference to FIG. The slide rings 12 and 18 are made of nylon or the like, the waterproof packing 13 is made of EPDM or the like, the first and second airtight seal rings 19 and 20 are made of NBR or the like, and the fireproof packing 21 is made of thermally expandable graphite. Etc. are formed.

  By the way, as a countermeasure against earthquakes, the displacement absorbing joint of FIG. 5 in which the waterproof seal portion is provided in the slide housing 9 and the airtight seal portion is provided on the inner end of the inner tube 2 as described above is about twice as long. For example, the length of 1442 ± 325 (mm) is increased to a length of 2755 ± 630 (mm), or the length of 1590 ± 330 (mm) is increased to a length of 2830 ± 630 (mm). Then, the waterproof packing 13 is provided only in the axial direction outer side of the slide ring 12 in the waterproof seal portion in the slide housing 9, and the axial direction of the first airtight seal ring 19 in the airtight seal portion at the inner end of the inner tube 2. If the slide ring 18 is provided only on the inner side, bending due to its own weight occurs when the inner and outer cylindrical tubes 2 and 1 are extended, and this bending increases the frictional force between the slide ring 12 and the inner cylindrical tube 2. Or scratches occur rubbing on the outer peripheral surface of the cylindrical tube 2, a problem that arises or not smoothly stretchable slide.

  Therefore, in the displacement absorbing joint of the present invention, in order to reduce the frictional force between the slide ring 12 and the inner tube 2 in the slide housing 9, as shown in FIGS. A waterproof packing 23 made of EPDM or the like is provided in the inner side of the first concave groove 10 in the axial direction of the first concave groove 10, and the seventh concave groove 22 is slidably adhered to the outer peripheral surface of the inner tube 2 in a watertight state. In other words, the waterproof packing 23 is provided side by side on the inner side in the axial direction of the slide ring 12, thereby strengthening the holding force of the inner tube 2 with the inner and outer waterproof packings 13 and 23 in the normal state and sliding. The ring 12 is placed in a non-contact state with a clearance from the outer peripheral surface of the inner tube 2. Accordingly, since the frictional force between the slide ring 12 and the inner cylinder tube 2 can be reduced, the inner cylinder tube 2 can be prevented from being rubbed by the slide ring 12, and there is no generation of scratches, and the sliding can be smoothly expanded and contracted. . The slide ring 12 exhibits the function of holding the inner tube 2 only when the waterproof packings 13 and 23 cannot hold the slide ring 12 due to external stress.

  On the other hand, an eighth concave groove 24 is provided side by side outside the sixth concave groove 17 on the outer periphery of the inner end portion of the inner cylindrical tube 2, and the eighth concave groove 24 is provided with respect to the inner peripheral surface of the outer cylindrical tube 1. The slide ring 25 made of slidable nylon or the like is fitted and held, that is, the slide ring 25 is also arranged side by side on the outer side in the axial direction of the second hermetic seal ring 20. The bending (inclination) of the inner tube 2 due to external stress can be reduced. Therefore, the effect of reducing the frictional force between the slide ring 12 and the inner cylindrical tube 2 and the effect of preventing the occurrence of scratches on the inner cylindrical tube 2 can be further enhanced.

  A hard chrome plating 26 is applied to the inner surface of the outer tube 1 so that it does not peel off or become scratched even if it is rubbed against the slide rings 18 and 25.

It is a side view of the displacement absorption joint of one Example of this invention. FIG. 2 is a half cutaway cross-sectional view showing an enlarged main part of the displacement absorbing joint of FIG. 1. It is a fragmentary sectional view which expands and shows the principal part of FIG. It is a side view of the displacement absorption joint of a prior art example. FIG. 5 is a half cutaway cross-sectional view showing an enlarged main part of the displacement absorbing joint of FIG. 4.

DESCRIPTION OF SYMBOLS 1 Outer cylinder pipe 2 Inner cylinder pipe 3, 4 Pipe connection part 5, 6 Ball joint mechanism 7, 8 Sliding surface 9 Slide housing 12, 18, 25 Slide ring 13, 23 Waterproof packing 19 First airtight seal ring 20 First 2 Airtight seal ring 26 Hard chrome plating

Claims (3)

The inner end of the inner tube (2) is slidably inserted in the axial direction at the inner end of the outer tube (1).
One end portion of the slide housing (9) externally fitted to the inner cylindrical tube (2) is screwed to the inner end portion of the outer cylindrical tube (1) and is connected to the inner periphery of the other end portion of the slide housing (9). A waterproof ring (13) that is slidably in close contact with the outer peripheral surface of the slide ring (12) and the inner tube (2) in a watertight state is held side by side in the axial direction,
On the outer periphery of the inner end of the inner tube (2), the inner tube (2) is held slidably with respect to the inner surface of the outer tube (1) and provided on the outer periphery of the inner tube (2). A slide ring (18) fitted and held in the recessed groove formed, and first and second airtight seal rings (19) and (20) slidable in close contact with the inner peripheral surface of the outer tube (1). In the displacement absorbing joint, which is held in order from the axially inner side to the axially outer side,
The slide ring (12) on the inner periphery of the other end of the slide housing (9) is in a non-contact state with the outer peripheral surface of the inner tube (2) in a normal state.
A waterproof packing (23) that is slidably in close contact with the outer peripheral surface of the inner tube (2) in a watertight state is held side by side inside the slide ring (12) in the inner periphery of the slide housing (9). And
On the outer periphery of the inner end of the inner tube (2), on the outer side in the axial direction of the second airtight seal ring (20), the inner tube ( A displacement absorbing joint, wherein the slide ring (25) for holding 2) is fitted and held side by side.   The displacement-absorbing joint according to claim 1, wherein a hard chromium plating (26) is applied to the inner surface of the outer tube (1).   Ball joints having spherical sliding surfaces (7) and (8) at the outer end portions of the outer tube (1) and the inner tube (2) and having pipe connection ports (3) and (4) The displacement absorption joint according to claim 1 or 2, wherein a mechanism (5) (6) is provided.

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