JPH0755430Y2 - Flexible pipe fittings - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a joint used for gas pipes, water supply pipes, hot water supply pipes, etc., through which a gas such as a flammable gas flows, and particularly to a bellows type flexible pipe. It relates to a joint for connecting pipes.

[Conventional technology]

Conventionally, as this type of joint, there is one shown in FIGS. 3 and 4. In FIG. 3, an end 61 of a bellows type flexible tube 60 is inserted into the joint body 40. The end 61 of the flexible tube 60 has a split ring with two splits.
Holds by 70. The locking ring 70 is pushed backward by a cap nut-shaped push ring 80 that is screwed into the male screw portion 40a formed on the outer periphery of the joint body 40, so that the joint body 40 and the tip portion 62 of the flexible pipe 60 are metal-touched. Airtight packing 90 at the tip of the locking ring 70
Is pressed to seal the outer circumference of the contact portion between the joint body 40 and the flexible tube 60. In order to prevent the flexible tube 60 from being twisted, the locking ring 70 is
It has a hexagonal shape as shown in the drawing, and is engaged with a hexagonal hole 41 formed in the inner circumference of the joint body 40. 63 is a coating layer for coating the flexible tube 60.

[Problems to be solved by the device]

In the conventional joint having the above-described structure, the locking ring 70 is provided as a rotation stop structure for preventing the rotational force of the pressing ring 80 from acting as a twisting force on the flexible tube 60 during the screwing rotation of the pressing ring 80. Has a hexagonal outer periphery,
A configuration is adopted in which it is engaged with a hexagonal hole 41 formed in the inner periphery of the joint body 40, and the hexagonal engagement portion receives the rotational force when screwing the push ring 80 into the joint body 40 and The rotational force is converted into an axial moving force of the locking ring 70 and an axial force for crimping the tip portion 62 of the flexible tube 60. Therefore, when the push ring 80 is screwed and rotated, a large frictional force acts between the hexagonal outer peripheral surface of the locking ring 70 and the hexagonal hole 41 on the joint body 40 side, and the push ring 80 is screwed in against this frictional force. Due to the need for rotation, a large rotational operating torque is required for a given pipe connection. For example, a large-diameter flexible tube 60 with a nominal size of 32A
Connection requires a very large rotational operation torque of about 30 kgf / m, and in order to obtain such a large rotational operation torque, a special power machine must be used. There is a drawback that it becomes extremely bad.

Further, it is unavoidable that the locking ring 70 slightly rotates with respect to the joint body 40 during tightening, and therefore the sharp edge of the distal end surface of the flexible tube 60 may damage the sealing surface.

In addition, as described above, the locking ring 70 is provided on the inner circumference of the joint body 40.
Since the hexagonal hole 41 is formed in the inner periphery of the joint body 40 by means of machining in order to engage the joint body 40, the joint body 40 cannot be machined only by a lathe. Therefore, the manufacturability of the joint is poor, which causes an increase in cost.

Further, in the above-mentioned conventional technique, since the hexagonal hole 41 is formed in the joint body 40, the joint body 40 is formed of a copper alloy having good machinability. If the joint body 40 is formed of such a copper alloy, stress corrosion cracking may occur. That is, the durability of the joint is low.

By the way, it is preferable that the caulking length of the tip portion 62 of the flexible tube 60 is a predetermined length in order to sufficiently exert the sealing performance. On the other hand, in this conventional technology,
Since 80 is screwed in, it is necessary to rely on the intuition of the operator for caulking length, which causes variations in caulking length. Therefore, the sealing performance also varies.

Further, since rainwater or the like may enter from the outside between the joint body 40 and the push ring 80, the airtight packing 90 may be attacked by rainwater, and the durability of the seal is low.

The present invention has been made in view of the above circumstances, and in addition to being excellent in manufacturability, durability and sealing performance, it reduces the rotational operation torque necessary for connecting a large-diameter flexible pipe, and reduces It is an object of the present invention to provide a flexible pipe joint capable of improving the workability of the.

[Means for Solving the Problems] In order to achieve the above-mentioned object, a flexible pipe joint according to the present invention is formed in a tubular portion into which an end portion of a bellows-shaped flexible pipe is inserted and protrudes inward. And has an annular step with which the tip of the flexible tube abuts,
A joint body in which a flange portion is integrally formed at the connection end of the tubular portion, and the tubular portion of the joint body is disposed inside the tubular portion, the outer periphery of which is circular, and the inner periphery of the flexible pipe is A locking ring that has a cross section along the outer shape and axially engages with the insertion end of the flexible pipe to hold the insertion end, and a fitting ring that is loosely fitted to the flexible pipe, An annular push ring that is fastened to the flange portion by a plurality of bolts and that pushes and moves the locking ring in the axial direction, and is pressed between the annular step portion of the joint body and the axial end surface of the locking ring. The airtight packing that seals the outer circumference of the contact portion between the joint body and the flexible pipe, and is inserted between the flange portion of the joint body and the push ring, and between the flange portion and the push ring. First watertight packing to seal And a second watertight packing that is attached to the inner peripheral portion of the push ring and seals between the outer periphery of the coating layer that covers the flexible pipe to the vicinity of the end portion and the inner periphery of the push ring. It will be.

[Operation] According to the present invention, when the push ring is fastened to the flange portion of the joint body with the plurality of bolts, the push ring axially pushes and moves the locking ring backward, and the flexible pipe is axially moved through the locking ring. Moving in the direction, the tip of the tip comes into contact with the inner annular step of the tubular part of the joint body, and the airtightness is maintained between the one axial end surface of the locking ring and the annular step of the joint body. The packing is pressed to seal the outer periphery of the contact portion between the joint body and the flexible pipe.
In addition, as the push ring is fastened to the flange portion of the joint body with bolts, the first watertight packing inserted between the flange portion of the joint body and the push ring is compressed, and both of them are compressed. A water-tight seal is provided between the push ring and the flexible pipe covering layer by a second watertight packing interposed between the inner periphery of the push ring and the outer periphery of the flexible tube covering layer. It

In this way, by adopting a flange joint configuration with a plurality of bolts as the connection structure between the joint body and the push ring, it is not necessary to rotate the push ring to exert a twisting force on the flexible pipe at the time of predetermined connection work. In addition, the tightening axial force of the bolt is never attenuated by the frictional force between the inner surface of the tubular portion of the joint body and the outer peripheral surface of the locking ring. Therefore, reducing the operating torque required to tighten the bolts, even with a large-diameter flexible pipe,
The predetermined connection can be performed with a small operation torque, and therefore the workability at the piping work site can be improved.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

In FIG. 1, a bellows-type flexible tube 1 is covered with a covering layer 1b except for its insertion end 1a. The insertion end portion 1a of the flexible pipe 1 has a joint body 2
Is inserted in the cylindrical portion 2a.

The joint main body 2 is made of, for example, malleable cast iron, and the joint main body 2 has an annular step portion 2b formed inwardly of the tubular portion 2a and protruding inward. The tip portion 1c of the flexible tube 1 contacts the annular step portion 2b. The joint body 2
Has a flange 2c at the connection end on the side connected to the flexible pipe 1, and has a male screw 2d on the outer periphery of the other end.
Are formed. A locking ring 3 is inserted and arranged inside the tubular portion 2a of the joint body 2.

As shown in FIG. 2, this locking ring 3 is formed from, for example, two half-divided portions 3A and 3B, and is split into two parts. As described above, the inner circumference thereof has a bellows-shaped cross section along the outer shape of the flexible tube 1, and engages with the flexible tube 1 in the axial direction. This locking ring 3 is a flexible tube 1
The flexible tube 1 is held in a state in which about 2 ridges of the tip end portion 1c are exposed.

An annular push ring 5 is fastened to the flange portion 2c of the joint body 2 by, for example, two bolts 4. The push ring 5 is loosely fitted on the flexible pipe 1 and is fastened to the flange portion 2c by the bolt 4 to push the locking ring 3 backward.

The annular step portion 2b of the joint body 2 has an annular recess 2b1, and between the annular recess 2b1 and the locking ring 3,
An O-ring forming the airtight packing 6 is inserted. The airtight packing 6 is pressed by the locking ring 3 and seals the outer circumference of the metal touch portion that is the contact portion between the flexible tube 1 and the joint body 2.

The flange portion 2c of the joint body 2 is provided with a first rubber member.
Groove into which the O-ring that constitutes the watertight packing 7A is fitted
2e is formed. The first watertight packing 7A is
It is inserted between the flange portion 2c of the joint body 2 and the push ring 5, and seals between the two 2, 5.

A groove 5a into which the T-shaped rubber packing that constitutes the second watertight packing 7B is fitted is formed on the inner circumference of the push ring 5. The second watertight packing 7B is integrally formed with a tongue piece 7b that protrudes inward. By mounting the watertight packing 7B in the groove 5a on the inner circumference of the push ring 5, the flexible pipe 1 The outer peripheral surface of the coating layer 1b and the inner peripheral surface of the push ring 5 are sealed.

Next, the connection method will be described.

First, the push ring 5 is inserted into the flexible pipe 1 up to a position where the second watertight packing 7B comes into contact with the coating layer 1b. Next, the split ring 3 is attached to the flexible tube 1 with the tip 1c of the flexible tube 1 exposed about two ridges. After this mounting, attach the flexible tube 1 to the locking ring 3
And the like into the joint body 2. At the time of this insertion, T
The tongue piece 7b of the second watertight packing 7B of the mold is inclined toward the tip side of the flexible tube 1 as shown by the alternate long and short dash line.

After the insertion, the joint body 2 and the push ring 5 push the locking ring 3 by the bolt 4 to move the locking ring 3 in the axial direction, and the axial movement of the locking ring 3 causes the tip of the flexible tube 1 to move. The portion 1c is compressed, the tip portion 1c is pressed against the annular step portion 2b of the joint body 2, and sealing is performed by metal touch. At the same time, the airtight packing 6 is compressed to seal the periphery of the metal touch portion which is the contact portion.

It should be noted that the T-shaped second watertight packing 7B has its tongue piece 7b tilted to the opposite end side of the flexible tube 1 as shown by the solid line by moving the push wheel 5 to the joint body 2 side at the time of fastening. .

In the above-mentioned structure, the push ring 5 only moves in the axial direction toward the joint body 2 side by the axial force of the bolt 4, and the push ring 5 does not rotate at all. Therefore, no rotational force acts on the locking ring 3. Therefore, the axial force of the bolt 4 acts as the caulking force of the tip portion 1c of the flexible pipe 1 as it is. Therefore, for example, when the flexible pipe 1 having a large diameter of 32A is connected, the torque required for tightening the bolt 4 is 5 kgf / m. It is possible to use a very small size, and as a result, the workability at the piping work site is improved.

Further, as described above, since no rotational force acts on the locking ring 3, it is not necessary to have a hexagonal outer shape in order to engage the locking ring 3 with the joint body 1 in the rotational direction, Both the inner circumference of the tubular portion 2a of the joint body 2 and the outer circumference of the locking ring 3 can be formed in a circular shape. Therefore, the joint body 2 can be machined mainly by a lathe. Manufacturability is improved.

Further, as described above, since it is not necessary to form the hexagonal hole in the joint main body 2, it is not necessary to use the copper alloy having good machinability for the joint main body 2, so that the joint main body 2 and the push ring 5 are the same. It can be made of a material, such as malleable cast iron. Therefore, stress corrosion cracking does not occur. Therefore, the durability of the joint is improved.

By the way, since the flange portion 2c of the joint body 2 and the push ring 5 are fastened with the bolt 4, the fastening is completed when the flange portion 2c and the push wheel 5 come into surface contact with each other. Therefore, by crimping the number of peaks of the tip portion 1c of the flexible tube 1 protruding from the locking ring 3 in advance, the caulking length becomes constant. Therefore, the sealing performance due to the metal touch is unlikely to vary, and the sealing performance is highly reliable.

Further, since the first and second watertight packings 7A and 7B are respectively inserted between the push ring 5 and the flange portion 2c and the coating layer 1b, rainwater or the like does not enter from the outside.
Therefore, the airtight packing 6 is not attacked by rainwater, and the durability of the seal is also improved.

The T-shaped watertight packing 7B has a good sealing property because the tongue piece 7b is inclined toward the side opposite to the tip of the flexible tube 1.

By the way, the flexible pipe joint according to the present invention is not limited to the above-mentioned embodiment, and for example, the locking ring 3 may not be composed of a pair of half-divided portions 3A and 3B. It may be divided into three or more parts, or it may be a C-shaped expandable part that is cut away in the circumferential direction. Further, the locking ring 3 is not limited to the one engaging with the plurality of valleys of the end 1a of the flexible tube 1 as in the above-mentioned embodiment, but it can be temporarily held in one valley to be held. May be.

Further, the airtight packing 6 is not limited to the O-ring, and may be a ring-shaped metal plate provided with sheet members such as rubber sheets on both side surfaces. In addition, in the ring-shaped packing using such a metal plate, it is necessary to flatten the annular stepped portion 2b without forming the annular recessed portion 2b1 on the outer periphery thereof.

[Advantages of the Invention] As described above, according to the present invention, by adopting a flange fastening form using a plurality of bolts as a connection structure between the joint body and the push ring, instead of a screw-in type, a predetermined connection work can be performed. There is no need to rotate the push ring that exerts a twisting force on the flexible pipe, and the axial force for tightening the bolt is attenuated by the frictional force between the inner surface of the tubular part of the joint body and the outer peripheral surface of the locking ring. Since the operation torque required for tightening bolts is reduced and a flexible pipe with a large diameter can be connected with a predetermined operation with a small operation torque, connection at the piping work site is easy. Therefore, the workability can be improved. Also, since the retaining ring is pushed back and the retaining ring is moved in the axial direction without rotating, it is possible to form both the inner surface of the tubular part of the joint body and the outer periphery of the retaining ring in a circular shape, and to improve their manufacturability. In addition, the same material as the push ring can be used as the constituent material of the joint body, and from the viewpoint of machinability, the stress corrosion cracking that occurs when the joint body is made of a copper alloy does not occur and durability is improved. It is possible to improve the sex. Furthermore, it is possible to make the distance between the joint body and the push ring constant,
Since the caulking length of the flexible pipe does not vary and the airtight packing is protected by the first and second watertight packings, the sealing property and the durability thereof can be improved. Play.

[Brief description of drawings]

FIG. 1 is a partially sectional side view showing an embodiment of the flexible pipe joint of the present invention, FIG. 2 is a sectional view taken along the line II-II of FIG. 1, and FIG. 3 is a conventional flexible pipe joint. FIG. 4 is a sectional view taken along line IV-IV in FIG. 1 ... Flexible tube, 1a ... End, 1b ... Coating layer, 1c
...... Tip part, 2 ...... Joint body, 2a ...... Cylindrical part, 2b ...... Annular step part, 3 ...... Locking ring, 4 ...... Bolt, 5 ...... Push ring, 6 ...... Airtight packing, 7A ...... First watertight packing, 7B …… Second watertight packing.

Claims (1)

[Scope of utility model registration request] 1. A tubular portion into which an end portion of a bellows type flexible tube is inserted has a circular step portion which is formed deeply and protrudes inward so that a tip portion of the flexible tube abuts.
A joint body in which a flange portion is integrally formed at the connection end portion of the tubular portion and a tubular portion of the joint body, the outer periphery of which is circular and the inner periphery of the flexible pipe is formed. A locking ring that has a cross section along the outer shape and that axially engages the insertion end of the flexible pipe to hold the insertion end, and a fitting ring that is loosely fitted to the flexible pipe and that An annular push ring that is fastened to the flange portion by a plurality of bolts to move the locking ring in the axial direction rearward, and is pressed between the annular step portion of the joint body and the axial end surface of the locking ring. And an airtight packing that seals the outer circumference of the contact portion between the joint body and the flexible pipe, and is inserted between the flange portion of the joint body and the push ring, and between the flange portion and the push ring. The first watertight seal to seal And a second watertight packing that is attached to the inner periphery of the push ring and seals between the outer periphery of the coating layer that covers the flexible pipe to the vicinity of the end thereof and the inner periphery of the push ring. Flexible pipe joint.