JPH0749183Y2 - Fittings for metal flexible tubes - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention is for connecting a joint used for a gas pipe or a hot water supply pipe for circulating a gas such as a combustible gas, particularly a corrugated metal flexible pipe. Regarding joints.

[Conventional technology]

Conventionally, this type of joint has been shown in FIGS. 3A and 3B. This is to push a pair of split ring retaining rings 120, 120 set in the joint body 100 at the rear end 111 of the nut body 110 when screwing the nut body 110 into the tubular joint body 100. Thus, the ridges a ₁ , of the corrugated metal flexible tube A set in the joint body 100 are
Pre-engagement retaining ring 12 between a ₁
0,120 pressing the end portion A ₁ of the metal flexible tube A by the engagement portion 121, 121 of the can pressing the end portion A ₁ of the metal flexible tube A an annular protrusion 101 which is provided to the joint body 100 by the pressing action It is like this.

According to such a joint, when the nut body 110 is completely tightened, the engaging portions 121, 121 of the retaining rings 120, 120 are
And the convex portion 101 of the joint body 100, the end of the metal flexible tube A.
A part of 1 to 3 peaks of A ₁ is pinched and the joint body 10
The convex portion 101 of 0 and the end portion A ₁ of the metal flexible tube A are metal-touched to form a fireproof seal structure. A concave portion 102 is formed on the outer peripheral portion of the convex portion 101 of the joint main body 100, and a rubber ring 130 such as an O-ring accommodated in the concave portion 102 is provided with the engaging portions 121 and 121 of the retaining rings 120 and 120 and the joint main body. The end portion A ₁ of the flexible metal tube A and the engagement portions 121, 121 of the retaining rings 120, 120 compressed by the convex portion 101 of 100 and the retaining ring 120, 120 are compressed to seal the periphery of the metal touch portion.

[Problems to be solved by the device]

However, when the metal flexible tube A is connected with the conventional joint, the meshing portions 121, 121 of the pair of split retaining rings 120, 120 are meshed with each other between the same ridges a ₁ , a ₁ of the metal flexible tube A. The retaining rings 120, 120 in an annular shape, and then the retaining rings 120, 120 in an annular shape.
Be careful not to lose the shape of the retaining ring 12
Put the fitting body 100 and the nut body 110 on the 0, 120
There was a problem that a careful and troublesome work of screwing the joint into the joint body 100 was required.

On the other hand, the nut body 1 is attached to the joint body 100 regardless of the procedure described above.
Connect the metal flexible tube A by loosely screwing 10 together with the retaining rings 120, 120 set in advance, inserting the metal flexible tube A therein and tightening the nut body 110. Is not necessarily impossible. However, in the case of such a procedure, the pair of retaining rings 120, 120 need to be set in such a state that their meshing portions 121, 121 are separated from each other so that the metal flexible tube A can be fitted therein. Fitting body 10
Inside the 0, the rattling of the pair of retaining rings 120, 120 is inevitably large, and so-called dancing of the retaining rings 120, 120 occurs so that the metal flexible tube A cannot be inserted properly, or even if it is inserted, the retaining ring is The meshing parts 121, 121 of the 120, 120 mesh with each other between the different peak parts a ₁ , a ₁ of the metal flexible tube A, so that a reliable metal touch cannot be formed.

The present invention has been made in view of the above circumstances, and ensures smooth, easy and reliable connection work with the retaining ring set in the joint body in advance without causing rattling of the retaining ring. Not only can it be carried out, but the meshing part of the retaining ring and the crest of the metal flexible tube can be engaged with the crest part of the metal flexible tube as the retaining ring shrinks regardless of the mutual positional relationship. It is an object of the present invention to provide a joint for a flexible metal tube, which is capable of accurately engaging with each other and exhibiting a reliable metal touch function and a reliable and strong retaining function in a connected state.

[Means for Solving the Problems] In order to achieve the above object, a joint for a metal flexible tube according to the present invention includes a tubular joint body into which a metal flexible tube having a corrugated cross section is inserted, and a metal flexible tube. A nut body that is screwed into the joint body in a state of being externally fitted to the joint body, and a retaining ring that is set inside the joint body where the nut body is screwed together. A peripheral portion is formed in a truncated circle shape whose diameter is set larger than the outer peripheral diameter of the metal flexible tube, and when the retaining ring is reduced in diameter, a meshing portion that meshes between the peak portions of the metal flexible tube is formed. The inner end portion of the meshing portion is formed so as to gradually expand from the minimum inner diameter point to both sides in the axial direction, and the tip end surface of the meshing portion extends from the gradually expanded end to the axial direction of the meshing portion. The nut body is formed in the orthogonal direction. Has a contact portion that pushes the retaining ring backward when screwed into the joint body, and the joint body slides with the retaining ring that is pushed by the nut body to move the retaining ring in the radial direction. It is characterized in that it has a taper-shaped guide surface that advances while reducing the diameter inward.

[Operation] According to the present invention, the retaining ring is previously set inside the joint body with the nut body screwed onto the joint body.
In this set state, the inner diameter of the retaining ring is expanded so as to be larger than the outer diameter of the metal flexible tube, and the retaining ring is connected to the guide surface of the joint body and the contact portion of the nut body. It is sandwiched between and is temporarily fixed so that it does not rattle. Therefore, in this state, when the metal flexible tube is inserted into the nut body, the retaining ring and the joint body, the retaining ring does not rattle, so that the metal flexible tube can be smoothly inserted. It is possible. When the metal flexible tube is thus inserted and the nut body is screwed into the joint body, the retaining ring is pushed backwards through the contact portion of the nut body and moves forward while the retaining ring moves forward. Is guided by the tapered guide surface of the joint body and is radially inwardly reduced, so that the meshing part meshes with the crests of the metal flexible tube. Here, the meshing portion of the retaining ring has a shape that gradually expands from the minimum inner diameter point of the inner end portion to both sides in the axial direction, and
Since the tip surface is formed in the direction orthogonal to the axial direction from the expanded end, regardless of the position of the crest portion of the metal flexible tube inserted into the engagement portion of the retaining ring, that is, For example, even if the meshing part comes into contact with the crest of the metal flexible tube, the metal flexible tube elastically deforms as the retaining ring shrinks in diameter. The flexible tube slides so that the meshing parts are accurately meshed with each other. Therefore, in a predetermined connection state, the metal flexible tube and the joint body can be surely metal-touched to form a predetermined fireproof seal, and a strong and secure retaining function can be exerted. Is.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

1A, 1B and 1C are longitudinal cross-sectional views of a main part of a metal flexible tube joint according to an embodiment of the present invention.

Reference numeral 1 denotes a tubular joint body having an inner thread 11 formed at one end and a stepped portion 13 having a small diameter having a tapered guide surface 12 formed at the terminal end of the inner thread 11. An annular convex portion 14 is formed at the inner end of the stepped portion 13, and a concave portion 15 is formed around the convex portion 14. An external thread 16 is formed on the other end of the joint body 1, and a threaded end of a straight or corrugated metal pipe is screw-connected to the other end having the external thread 16. ing.

Reference numeral 2 denotes a nut body having an external thread 21 at its tip and an inner surface of the tip forming an outwardly extending tapered tapered contact portion 22.
An outer screw 21 of the nut body 2 is screwed onto an inner screw 11 of the joint body 1.

Reference numeral 3 denotes a retaining ring formed of a cylindrical body, which has a cutout shape as shown in FIG. 2A, and the front end of the cylindrical portion 31 has a corrugated metal flexible shape when the retaining ring 3 is reduced in diameter. An intermeshing portion 32 is provided which engages between the ridges a ₁ and a ₁ of the pipe A, and the inner end portion 32 a of the engaging portion 32 is gradually expanded from the minimum inner diameter point to both sides in the axial direction. And the tip surface 32b of the meshing portion 32 is formed from the end of the inner end portion 32a to the meshing portion 32.
Is formed to be flat in a direction orthogonal to the axial direction of the guide surface 12 of the joint body 1 on the outer periphery of the meshing portion 32.
A tapered surface 33 that slides with is formed. Further, on the outer periphery of the rear end of the cylindrical portion 31, a tapered surface 34 that slides on the contact portion 22 of the nut body 2 is formed. The retaining ring 3 has a meshing portion 32 whose inner diameter in the natural state is larger than the outer diameter of the corrugated metal flexible tube A, and moreover, the cutout portion shown in FIG. 2A. When the entire retaining ring 3 is reduced in diameter against its own elasticity so that the gap 35 of the stopper ring 3 is completely closed as shown in FIG.
The inner peripheral diameter of the metal flexible tube A is equal to or slightly smaller than the outer peripheral diameter of the valley portion a ₂ of the metal flexible tube A.

When the outer thread 21 of the nut body 2 is screwed onto the inner thread 11 of the joint body 1 and the retaining ring 3 is set inside thereof, the tapered surface 33 and the taper 33 in the natural state of the retaining ring 3 to be set are set. Even if there is some difference in the outer diameter of the surface 34, the guide surface 12 of the joint body 1 and the contact portion 22 of the nut body 2
If the nut body 2 is screwed in such a manner that the retaining ring 3 is sandwiched between and fixed, the retaining ring 3 is fixedly set without rattling. Therefore, when the metal flexible tube A is inserted into the joint, the retaining ring 3 does not rattle and it is difficult to insert it. Even in such a set state, the inner peripheral diameter of the meshing portion 32 of the retaining ring 3 is larger than the outer peripheral diameter of the mountain portion a ₁ of the metal flexible tube A, and the gap 35 remains open. It is kept.

When connecting the metal flexible tube A waveform, convex metal flexible tube A is its end A ₁ of the joint main body 1 as in Figure 1A to the joint that is set in the retainer ring 3 as described above After inserting to the position where it hits the portion 14, the nut body 2 screwed to the joint body 1 is screwed in the arrow X direction. By doing so, the retaining ring 3 is pushed backward by the abutting portion 22 of the nut body 2, and accordingly, the guide surface 12 of the joint body 1 slides on the tapered surface 33 of the retaining ring 3 so that the retaining ring 3 has a radius. As the diameter of the metal flexible tube A advances, the meshing portion 32 of the retaining ring 3 meshes with the crests a ₁ and a ₁ of the metal flexible tube A in the middle of the process. Here, the engagement portion 32 of the retaining ring 3 has a shape that gradually expands from the minimum inner diameter point of the inner end portion 32a to both sides in the axial direction, and the tip surface 32
Since b is formed flat from the expanded end in the direction orthogonal to the axial direction, the meshing portion 32 of the retaining ring 3 and the mountain portion a ₁ of the metal flexible tube A have a positional relationship such as the meshing portion. Even if 32 has a positional relationship such that it hits the mountain portion a ₁ of the metal flexible tube A, the metal flexible tube A is elastically deformed due to the contraction of the retaining ring 3, and finally the meshing portion 32. Slips into proper engagement between the peaks a ₁ , a ₁ and the end A ₁
Is pressed against the convex portion 14 of the joint body 1. Then, the nut body 2 is completely screwed in (in this state, the tapered surface 33 of the retaining ring 3 exceeds the guide surface 12 and the retaining ring 3 is backed up from the outside by the inner surface of the stepped portion 13. ), As shown in FIGS. 1C and 2B, a portion of the end portion A ₁ of the flexible metal tube A is clamped between the meshing portion 32 of the retaining ring 3 and the convex portion 14, At the same time the end a ₁ of metal flexible tube a refractory seal is constituted by metal touch and the convex portions 14, mutual mountain portion a _1, a ₁ end a ₁ of metal flexible tube a Further, the engagement portion 32 of the retaining ring 3 surely engages with each other, and a reliable and strong retaining action is exhibited.

By the way, if a rubber ring 4 such as an O-ring is previously installed in the recess 15 of the joint body 1 as shown in FIG. 1A, when the nut body 2 is completely screwed in, the rubber ring 4 becomes a metal flexible tube. It is compressed by the pressed end portion A ₁ of A and is pressed against the surface of the recess 15 to seal the periphery of the metal touch portion. However, this rubber ring 4 is not essential. Further, if necessary, an expanded graphite ring may be interposed between the rubber ring 4 and the metal touch portion. If this is done, the rubber ring 4 may be melted by heat during a fire or the like. In the case where the rubber ring 4 burns and the sealability is impaired, the expanded graphite ring is expanded by receiving heat at that time, which helps maintain the sealability around the metal touch portion. In addition, the sealing property is exhibited by the metal touch portion regardless of whether the ring made of expanded graphite is interposed or not.

In the connecting process described above, when the retaining ring 3 is reduced in diameter and its meshing portion 32 is in pressure contact with the outer peripheral surface of the metal flexible tube A, the frictional engagement force associated with the pressure contact is the guide surface 12 and the tapered surface 33. And the frictional engagement force between the contact portion 22 and the tapered surface 34 are larger than the entire frictional engagement force. Therefore, after the engagement portion 32 of the retaining ring 3 is pressed against the outer peripheral surface of the metal flexible tube A, the retaining ring 3 will not rotate even if the rotational force accompanying the screwing of the nut body 2 is applied to the retaining ring 3. The metal flexible tube A moves forward while reducing its diameter without co-rotating with the body 2, and a twisting force is applied to the metal flexible tube A.
There is no chance that he will be twisted. Also, the nut body 2
Since the contact portion 22 is formed in a tapered shape, it is useful not only for pushing the retaining ring 3 backward, but also for facilitating the reduction of the retaining ring 3. However, even if the contact portion 22 is replaced with a vertical surface in a direction orthogonal to the axial center of the nut body 2, the retaining ring is actuated by the action of the guide surface 12 of the joint body 1 and the tapered surface 33 of the retaining ring 3. 3 is promoted to reduce the diameter of the retaining ring 3, and the retaining ring 3 reduces its diameter while advancing. Therefore, in this case, the vertical surface functions to push the retaining ring 3 while allowing the diameter of the retaining ring 3 to be reduced.

[Effect of device]

As described above, according to the present invention, in the natural state, the retaining ring, which has an inner diameter larger than the outer diameter of the flexible metal tube and has a truncated circular shape, is advanced along with the screwing of the nut body. However, the retaining ring is temporarily fixed by sandwiching the retaining ring between the contact part of the nut body and the tapered guide surface provided on the joint body so as to face it. The retaining ring is set in advance inside the joint body in a state where the nut body is screwed onto the joint body, and then the metal flexible tube is inserted to secure the nut body. When adopting a rational work procedure such as screwing, even if there is some error in the outer diameter of the retaining ring, rattling of this retaining ring is prevented and the metal flexible tube is very smooth and easy. Plug into It can, facilitate the connection work than the conventional, it is possible to reliably reduction.

Moreover, the engagement portion of the retaining ring has a shape that gradually expands from the minimum inner diameter point of its inner end portion to both sides in the axial direction, and its tip surface is formed in a direction orthogonal to the axial direction from the expanded end. Therefore, even if the relative position is such that the meshing part hits the crest of the metal flexible tube, the metal retaining tube is prevented from deforming within the elastic range due to the shrinkage of the metal retaining ring while retaining the metal retaining tube. The meshing portion of can be accurately meshed with each other between the crests of the metal flexible tube, and therefore, the metal flexible tube and the joint body can be surely metal-touched in a predetermined connection state to provide a predetermined fireproof seal. In addition to being able to form reliably, it is possible to exert a strong and powerful retaining function, and in particular, to achieve a marked improvement in safety as a joint for piping that handles flammable gas etc. But Kill.

[Brief description of drawings]

1A, 1B and 1C are partial sectional views of a joint according to an embodiment of the present invention, and FIGS. 2A and 2B are lines IIA-IIA in FIG. 1A and IIB-IIB line in FIG. 1C, respectively. A cross-sectional view showing the metal flexible tube and the retaining ring viewed from a portion along the line, FIG. 3A is a partial sectional view of a conventional example, and FIG. 3B is a positional relationship between the metal flexible tube and the retaining ring in the conventional example. FIG. A ... Metal flexible tube, 1 ... Joint body, 2 ... Nut body,
3 …… retaining ring, 12 …… guide surface, 14 …… convex part, 22
…… Abutting part, 31 …… Cylindrical part, 32 …… Mating part, 33 …… Taper surface of the retaining ring.

Claims (1)

[Scope of utility model registration request] 1. A tubular joint body into which a metal flexible tube having a corrugated cross section is inserted, a nut body screwed onto the joint body in a state of being externally fitted to the metal flexible tube, and this nut body is screwed together. And a retaining ring set inside the joint body, wherein the retaining ring is formed in a truncated circle shape with an inner diameter set to be larger than an outer diameter of the metal flexible tube in a natural state. When the retaining ring is reduced in diameter, a meshing portion that meshes between the crests of the metal flexible tube is provided, and the inner end portion of this meshing portion gradually expands from the minimum inner diameter point to both sides in the axial direction. And the distal end surface of the meshing portion is formed in a direction orthogonal to the axial direction of the meshing portion from the gradually expanded end, and the nut body is removed when the nut body is screwed into the joint body. Has a contact to push the retaining ring. The joint body has a tapered guide surface that slides on the retaining ring pushed by the nut body to advance the retaining ring while radially contracting the retaining ring inward. A fitting for a flexible metal tube.