JP6029096B2 - Pipe joint structure - Google Patents

Description

The present invention relates to a pipe joint structure used for connecting a tubular body made of, for example, a hose or a tube to a nipple.
More specifically, the present invention relates to a pipe joint structure of a pipe body in which at least an inner surface is difficult to undergo diameter expansion deformation.

Conventionally, as this type of pipe joint structure, an insertion portion to be inserted into a hose is provided at the tip portion of the nipple, and a plurality of ring-shaped protrusions are formed along the outer periphery of the insertion portion, The outer diameter is substantially the same size as the inner diameter of the hose, the insertion portion can be press-fitted into the hose, the inner diameter of the sleeve member is slightly larger than the outer diameter of the hose, and can be attached to the outside of the hose, In order to connect the hose to the nipple, first, the sleeve member is attached to the tip of the hose, and then the nipple is inserted into the hose until the hose contacts the engaging protrusion of the nipple. There is one that crimps the sleeve member to deform its diameter (for example, see Patent Document 1).
Moreover, there is a laminated hose for food in which an inner layer and an intermediate layer are laminated on the outer side of the innermost layer made of an ethylene-tetrafluoroethylene copolymer (ETFE) such as EFEP as a tubular body whose inner surface is difficult to expand and deform at least. (For example, refer to Patent Document 2).

JP 2006-002911 A JP 2005-282630 A

In the conventional pipe joint structure as in Patent Document 1, the outer diameter of the nipple projection is set to be substantially the same size as the inner diameter of the hose, so that the inner surface as in Patent Document 2 is difficult to expand and deform. Even if there is, nipple can be inserted smoothly.
However, since the inner surface of the tube body easily slides and moves with respect to the nipple, the tube body may be displaced in the axial direction with respect to the nipple as the diameter of the sleeve decreases.
In this way, when the tube body is not set correctly with respect to the nipple and is coupled while being displaced in the axial direction, there is a problem in that the tube body with respect to the nipple is lowered and the tube body is easily removed. .
Moreover, as a usage method of a pipe joint structure, there are a case where it is used by being immersed in a liquid, and a case where it is immersed in a cleaning liquid after use for cleaning.
However, in such a conventional pipe joint structure, there is a slight gap between the end of the crimped sleeve and the outer peripheral surface of the nipple. There is also a problem that the inside of the sleeve is infiltrated by a capillary phenomenon (capillary phenomenon), and the pulling strength of the tubular body is reduced, or a fluid enters the inside from the distal end surface of the tubular body.

  An object of the present invention is to cope with such a problem. Even if the inner surface of the tubular body is difficult to be enlarged and deformed, it is possible to achieve both insertion into the nipple and prevention of displacement, and reduce the diameter of the sleeve. The purpose is to securely connect the three parties.

In order to achieve such an object, a pipe joint structure according to the present invention includes a tubular body having an inner surface that is difficult to expand and deform, a nipple inserted along the inner surface of the tubular body, and an outer side of the nipple. and a sleeve for pressing the tube body to the direction of reducing the diameter deformably provided so as to cover across the tube body, the tube body is hardly hard material layer constituting the inner surface is enlarged deformed And an outer peripheral surface of the nipple is formed with a plurality of annular protrusions formed in the axial direction of the nipple so that the diameter gradually increases and inclines in the tube insertion direction, and the plurality of annular protrusions. and a circular smooth portion is a plurality of sets formed alternately in the axial direction of the nipple possess between the outer diameter of said plurality of annular smooth portion is set to substantially the inner diameter of the tubular body the same, said plurality of annular than the maximum outer diameter inner diameter of the tubular body of the projection is slightly larger, Serial sleeve, in a state in which the tubular body with the shrink deformation of its is pressurized to diameter reduction direction, the inner surface of the pipe body is pressed against the annular projection of the outer peripheral surface of the nipple closely Uchishu It has a surface .

In the present invention having the above-described features, by inserting a nipple along the inner surface of the tubular body that is difficult to expand and deform, the inner surface of the tubular body gradually moves along the inclined surface of the annular projecting portion when passing through the annular projecting portion. Although it has a large diameter deformation, it can easily overcome the annular protrusion, and when passing through the annular smooth part, the inner surface of the tube slides smoothly, so it can be securely inserted to a fixed position, After that, when the sleeve is reduced in diameter toward the nipple, the top portion of the annular protrusion bites into the inner surface of the tube body, so the tube body is temporarily fixed to the nipple so that it cannot be displaced in the axial direction. Since it is sandwiched between the nipples, even if it is a tube body whose inner surface is difficult to be expanded in diameter, the insertion of the nipple and the prevention of misalignment can be achieved, and the three members can be securely coupled by the reduced diameter of the sleeve.
As a result, the nipple can be easily inserted without going through a preparatory process such as heating the tube before inserting the nipple, and the outer diameter of the protrusion of the nipple is set to be approximately the same as the inner diameter of the hose. Compared to the above, the pipe body can be connected to the nipple without lowering the drop strength, and the pipe body can be completely prevented from coming off.

It is explanatory drawing (partially notched front view) which shows the whole structure of the pipe joint structure which concerns on embodiment of this invention, and has shown before diameter reduction of a sleeve. It is a partially notched front view which expands further and shows the diameter reduction of the sleeve. It is explanatory drawing (partially notched front view) which shows the whole structure of the pipe joint structure which concerns on other embodiment of this invention, and expands and shows before diameter reduction of a sleeve. It is a partially notched front view which expands further and shows the diameter reduction of the sleeve.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
As shown in FIGS. 1 to 4, a pipe joint structure A according to an embodiment of the present invention includes a tubular body 1 having an inner surface 1 a that is difficult to expand and deform, and a nipple that is inserted along the inner surface 1 a of the tubular body 1. 2 and a sleeve 3 provided outside the nipple 2 so as to sandwich and cover the tubular body 1 in the radial direction and pressurizing and tightening the tubular body 1 in the reduced diameter direction are provided as main components.

The tubular body 1 is a pipe formed of a soft material such as a soft synthetic resin or rubber, for example, a hose, a tube, or a hard material, and preferably has a flat inner surface 1a and outer surface 1b. The tubular body 1 having the inner surface 1a that is difficult to expand and deform is composed of a laminated structure in which at least the layer constituting the inner surface 1a is made of a material that is difficult to expand and deform, or a hard material that is difficult to expand and deform inside. The reinforcing layer is embedded so that it has excellent shape retention and pressure resistance. This reinforcing layer is constituted by winding a plurality of or a single reinforcing wire such as a hard synthetic resin wire or a metal wire, spirally wound in the axial direction, or linearly arranged in the axial direction.
As a specific example of the tubular body 1, a first resin layer (innermost layer) 1A made of an ethylene-tetrafluoroethylene copolymer (ETFE) such as transparent EFEP as described in JP-A No. 2005-282630 is used. And a second resin layer (inner layer) 1B made of a polyamide-based resin such as transparent modified nylon 12 to which an alkyl hydroxybenzoate plasticizer is added, and a third resin layer (intermediate layer) 1C made of a transparent polyurethane-based elastomer And a fourth resin made of a synthetic resin such as transparent vinyl chloride on the outer surface of the third resin layer 1C and a net-like reinforcing layer made of a reinforcing wire 1D such as a fiber. A laminated hose in which layers (outer layers) 1E are laminated is used.
Although not shown in the drawings as another example, as the tube body 1, an adhesive layer is provided between the inner layer, the outer layer, and the reinforcing wire, or the fluid or gas passing through the tube body 1 inside the inner layer as necessary. An innermost layer made of a material is integrally provided, an outermost layer made of a protective material is integrally provided outside the outer layer, or a reinforcing layer made of a reinforcing wire such as a plurality of synthetic resin blades (reinforcing yarns) is provided. Laminate or integrate a reinforcing wire such as a synthetic resin or metal cross-sectional rectangle and a reinforcing wire such as a circular cross-section spirally as an intermediate layer, or integrate a reinforcing wire such as glass fiber or flame retardant fiber It is also possible to braid, to dispose the reinforcing wire 1D between the inner layer and the outer layer made of an opaque material, or to use a single-layer structure tube or the like.

The nipple 2 is formed in a cylindrical shape by processing a hard material such as a metal such as brass or a hard synthetic resin, for example, and is provided so as to face the inner surface 1 a of the connection end portion in the tube body 1.
On the outer peripheral surface of the nipple 2, an annular protrusion 2a that gradually increases in diameter in the insertion direction of the tube 1 and inclines in a tapered shape, and an annular smooth portion 2b having the same outer diameter in the axial direction of the nipple 2, A plurality of pairs are alternately formed in the axial direction of the nipple 2 and are formed so as to be in the shape of bamboo shoots.
As shown in FIGS. 1 and 2, the annular protrusion 2 a has a tapered inclined surface gradually expanding in the insertion direction of the tube body 1 and a stepped portion continuous therewith, so that the outer shape of the nipple 2 is a bamboo shoot. It is preferable to form so that it may become a shape (cross-sectional sawtooth shape). Although not shown as another example, the annular protrusion 2a can be formed in a mountain-shaped cross section by an inclined surface opposite to the tapered inclined surface.
The outer diameter of the annular smooth portion 2 b is set to be substantially the same as the inner diameter of the tube body 1, and the outer diameter of the top portion having the largest diameter in the annular protrusion 2 a is set slightly larger than the inner diameter of the tube body 1.
Further, on the outer peripheral surface of the nipple 2, an annular first locking portion 2 c is integrally formed or integrally formed so as to face one end of a sleeve 3 to be described later, and the first locking portion 2 c is formed. An annular concave groove 2d is formed adjacent to the back side of the.

The sleeve 3 is made of a deformable material and is formed in a substantially cylindrical shape having an inner diameter larger than the outer diameter of the tube body 1. The sleeve 3 is inserted into the connecting end of the tube 1 along the inner peripheral surface thereof, and after the nipple 2 is inserted into the connecting end of the tube 1, the sleeve 3 is deformed by a hydraulic device or a manual tool. By doing so, the inner surface 1 a of the tube body 1 is tightened so as to be in pressure contact with the outer peripheral surface of the nipple 2.
As a specific example of the sleeve 3, as shown in FIGS. 2 and 4, a caulking pipe made of a plastically deformable rigid material that is deformed by a hydraulic device or the like but is not deformed by a repulsive force from the tube 1 is used. preferable. Specifically, the caulking pipe that becomes the sleeve 3 is plastically deformed and reduced in diameter by a hydraulic device (not shown) such as a caulking machine, whereby the tubular body 1 is elastically compressed in the radial direction, and the inner surface 1a thereof is a nipple. 2 is in pressure contact with the outer peripheral surface.
Although not shown in the drawings as other examples, the sleeve 3 is a cylindrical holder that can be reduced in diameter in the radial direction of the tube body 1, a holder that divides the cylindrical body into a plurality of radial directions, and a belt-like body by rotating the tool. It is also possible to use a tightening tool (hose band) or the like that gradually tightens.

An annular protrusion 3 a that protrudes toward the outer surface 1 b of the tube 1 is integrally formed or integrally formed on the inner peripheral surface of the sleeve 3, and the inner diameter of the annular protrusion 3 a is substantially equal to the outer diameter of the tube 1. It is preferable to set the same.
In the sleeve 3, the tip edge 3 b on the tip side in the axial direction is preferably protruded more toward the tip than the tip edge 2 e of the nipple 2 in the assembled state with respect to the nipple 2 shown by a solid line in FIGS.
Although not shown in the drawings as other examples, the tip edge 3b of the sleeve 3 is arranged substantially the same as the tip edge 2e of the nipple 2, or the tip edge 3b of the sleeve 3 is arranged on the back side of the tip edge 2e of the nipple 2. It is also possible to do.

Further, an annular second locking portion 3c is integrally formed or integrally formed at the back end of the sleeve 3 so as to be bent toward the annular first locking portion 2c formed on the outer peripheral surface of the nipple 2. Protrusively formed.
The second locking portion 3c is brought into contact with the first locking portion 2c of the nipple 2 in the axial direction as the sleeve 3 is reduced in diameter as shown in FIGS. Is preferably positioned in the axial direction.
In particular, as shown in FIGS. 2 and 4, the second locking portion 3 c enters the recessed groove portion 2 d on the back side of the first locking portion 2 c as the sleeve 3 is reduced in diameter, and engages both. It is preferable to make it.
Although not shown as another example, the sleeve 3 is pivoted with respect to the nipple 2 by completely fitting the second locking portion 3c into the annular concave groove portion 2d as the sleeve 3 is reduced in diameter. It is also possible to prevent it from coming off in the direction.

Next, a method of connecting the pipe body 1 to the pipe joint structure A according to the embodiment of the present invention will be described in accordance with the assembly procedure.
First, as shown by a two-dot chain line in FIGS. 1 and 3, the connecting end portion of the tube body 1 is inserted along the inner peripheral surface of the sleeve 3 and assembled together.
Subsequently, as shown by a solid line in FIGS. 1 and 3, the sleeve 3 to which the connecting end of the tube 1 is assembled is moved toward the nipple 2 or the nipple 2 is moved to The surface is inserted along the inner surface 1 a with respect to the connection end of the tube body 1.
Thereafter, as shown by a two-dot chain line and a solid line in FIGS. 2 and 4, the sleeve 3 is deformed to reduce the diameter toward the nipple 2, and the connecting end portion of the tubular body 1 is connected to the outer peripheral surface of the nipple 2.

According to such a pipe joint structure A according to the embodiment of the present invention, when the nipple 2 is inserted along the inner surface 1a of the pipe body 1 that is difficult to expand and deform, the pipe body 1 is passed through the annular protrusion 2a. Since the inner surface 1a of the ring gradually expands and deforms along the inclined surface of the annular protrusion 2a, although there is resistance, the annular protrusion 2a can be easily overcome. Furthermore, since the inner surface 1a of the tubular body 1 slides smoothly when passing through the annular smooth portion 2b, it can be reliably inserted to a fixed position. Thereafter, the diameter of the sleeve 3 is reduced toward the nipple 2 so that the top portion of the annular protrusion 2a bites into the inner surface 1a of the tube 1 so that the tube 1 cannot be displaced in the axial direction with respect to the nipple 2. It is sandwiched between the sleeve 3 and the nipple 2 while being temporarily fixed.
Therefore, even if the inner surface 1a is a tube body 1 that is difficult to be expanded and deformed, the insertability with respect to the nipple 2 and the prevention of positional deviation can be achieved, and the three members can be reliably coupled by the reduced diameter of the sleeve 3.
As a result, the nipple 2 can be easily inserted without going through a preparatory process such as heating the tube body 1 before inserting the nipple 2.
Next, each embodiment of the present invention will be described with reference to the drawings.

  In the first embodiment, as shown in FIGS. 1 and 2, the sleeve 3 is a rigid material such as aluminum in which the sleeve 3 is compressed and deformed by a driving caulking machine (not shown) or a manual hydraulic caulking machine (not shown). This is an oak pipe molded in By tightening the caulking pipe to be the sleeve 3 into a regular octagonal cross section by a driving caulking machine and reducing the diameter of the caulking pipe, the entire circumference of the caulking pipe is uniformly tightened. The annular protrusion 2a and the annular smooth portion 2b on the outer peripheral surface of the nipple 2 are pressed against each other, and are connected so as not to be displaced in the axial direction by biting of the annular protrusion 2a.

  Further, in the example shown in FIGS. 1 and 2, an annular convex portion 3 a is formed to project from the distal end side on the inner peripheral surface of the sleeve 3. The tip edge 3b of the sleeve 3 protrudes to the tip side from the tip edge 2e of the nipple 2, and an inverted tapered surface 2f having a diameter expanded toward the tip is formed on the tip inner peripheral surface of the nipple 2.

According to such a pipe joint structure A according to the first embodiment of the present invention, the annular projection 3a of the sleeve 3 bites into the outer surface 1b of the tubular body 1 by deforming the sleeve 3 to reduce the diameter toward the nipple 2. The tube body 1 is positioned so as not to move in the axial direction.
Therefore, there is an advantage that the pull-out strength of the tube body 1 can be further improved.

In particular, in the case shown in FIG. 1 and FIG. 2, due to the diameter-reducing deformation of the sleeve 3, the tubular body 1 is pushed inward by the annular convex portion 3 a and the inner end portion 1 a 1 is pushed inward. The inner end portion 1a1 is disposed so as to be continuous with the reverse tapered surface 2f of the nipple 2.
Thereby, there is an advantage that it is possible to prevent the accumulation of impurities such as a liquid pool by eliminating the step between the tip edge 2e of the nipple 2 and the inner surface 1a of the tube body 1.

Further, on the outer peripheral surface of the nipple 2, a cylindrical joint body 20 having a larger diameter than that of the first locking portion 2 c and the annular groove portion 2 d is integrally formed. The joint body 20 is formed with a connection portion 20a for connecting to a pipe connection port (not shown) of another device.
At the time of inserting the nipple 2 into the connecting end of the sleeve 3 and the tubular body 1 indicated by a two-dot chain line and a solid line in FIG. 1, the annular second engaging portion 3c of the sleeve 3 is connected to the annular concave groove 2d. It is preferable that the annular second engaging portion 3c of the sleeve 3 is positioned so as to face the annular concave groove portion 2d of the nipple 2 in the radial direction by abutting against a step portion formed between the joint bodies 20. .
2, the annular second locking portion 3c is fitted into the annular concave groove portion 2d of the nipple 2, and the sleeve 3 is axially moved with respect to the nipple 2. As shown in FIG. It is prevented from slipping out.

In the example shown in FIGS. 1 and 2, the connecting portion 20a is a flange, and a concave groove 20b into which an O-ring (not shown) is inserted is formed on the connecting end face.
Although not shown in the drawings as another example, the nipple 2 is formed separately from the joint body 20, and the nipple 2 is detachably attached to the joint body 20, or the connection portion 20a is replaced with a flange. It is also possible to form a tool engaging portion with which a tool such as a screw portion, a spanner or a wrench engages on the surface.

  As shown in FIGS. 3 and 4, the second embodiment includes an elastically deformable sealing material 4 provided between the nipple 2 and the sleeve 3 so as to be adjacent to the distal end surface 1 c of the tube body 1 in the axial direction, Unlike the first embodiment shown in FIGS. 1 and 2, the configuration provided with the engaging portion 5 formed so as to be adjacent to the sealing material 4 in the axial direction between the nipple 2 and the sleeve 3 is different. The configuration is the same as that of the first embodiment shown in FIGS.

The sealing material 4 is formed in an annular or cylindrical shape with an elastically deformable material such as rubber, for example, and the first locking portion 2 c of the nipple 2, the second locking portion 3 c of the sleeve 3, and the distal end surface 1 c of the tube body 1. Are arranged adjacent to each other in the axial direction.
Furthermore, the sealing material 4 includes a distal end surface 1c of the tube body 1 and a first seal surface 4a facing the axial direction thereof, an engagement portion 5 described later, and a second seal portion 4b facing the axial direction thereof. Yes. The seal material 4 expands and deforms in the axial direction along with the diameter reduction of the sleeve 3 to bring the first seal surface 4a into intimate contact with the distal end surface 1c of the tube body 1 and the second seal portion 4b to be an engagement portion 5 described later. The nipple 2 and the sleeve 3 are in close contact with each other.

  The engaging portion 5 is an annular space that is defined between the first locking portion 2 c of the nipple 2 and the second locking portion 3 c of the sleeve 3 so as to face the second seal portion 4 b of the sealing material 4. Or an annular gap formed so as to face the second seal portion 4b of the sealing material 4 at the contact portion between the first locking portion 2c and the second locking portion 3c.

In the example shown in FIGS. 3 and 4, the engagement portion 5 is an annular space portion having a through-hole 5 a continuous in the axial direction toward the exposed surface 6 of the nipple 2 or the sleeve 3.
The radial width of the annular space before the diameter reduction of the sleeve 3 shown in FIG. 3 is set larger than the diameter reduction width of the sleeve 3 shown in FIG.
The second seal portion 4b of the seal material 4 has an annular protrusion 4c that is fitted into the through hole 5a.
Further, although not shown as another example, the engaging portion 5 may be an annular gap instead of the annular space portion. The second seal portion 4b of the seal material 4 may be a substantially smooth surface on which the annular protrusion 4c is not formed in the state before the diameter reduction of the sleeve 3 shown in FIG.

According to such a pipe joint structure A according to the second embodiment of the present invention, when the sleeve 3 is deformed to reduce the diameter toward the nipple 2, the seal material 4 is expanded and deformed in the axial direction, and the first seal surface 4a. Is in close contact with the distal end surface 1c of the tube body 1 and at the same time, the second seal portion 4b is press-fitted into the engaging portion 5 and is in close contact with the nipple 2 and the sleeve 3, respectively. 3 does not enter from the outside to the inside.
Therefore, the fluid can be prevented from entering from the outside to the inside of the sleeve 3 with a simple structure.
As a result, it is possible to prevent a drop in the strength of the tubular body 1 from being lowered or a decline in the function of the tubular body 1 due to the ingress of moisture, and it is economical because it can be used for a long time.

Further, as in the specific example illustrated as the tubular body 1, when a material in which a reinforcing layer made of a reinforcing wire 1 </ b> D is embedded in the axial direction is used, the sealing material is reduced along with the diameter reduction of the sleeve 3. 4 expands and deforms in the axial direction, and the first seal surface 4a is in intimate contact with the distal end surface 1c of the tube body 1, so that the fluid does not enter along the reinforcing layer made of the reinforcing wire 1D.
Therefore, it is possible to completely prevent the fluid from entering the reinforcing layer of the tube body 1.
As a result, the shape retaining property and pressure resistance of the tube body 1 are not lowered, and even if the inner layer and the outer layer are transparent or translucent, they can be used for a long time without discoloration.

In the example shown in FIGS. 3 and 4, the annular protrusion 4 c formed to protrude from the second seal portion 4 b of the sealing material 4 is replaced with the end face 4 d of the annular protrusion 4 c as the diameter of the sleeve 3 decreases. Inflated and deformed so as to be substantially flush with the exposed surface 6.
The term “substantially flush with the exposed surface 6” as used herein refers to the annular protrusion 4 c with respect to the exposed surface 6 of either the nipple 2 or the sleeve 3 or the exposed surface 6 of both the nipple 2 and the sleeve 3. The end surface 4d of the annular protrusion 4c is inflated and deformed so that the end surface 4d is flush with the exposed surface 6, or the end surface 4d of the annular projection 4c is slightly expanded from the exposed surface 6.

In particular, in the case shown in FIGS. 3 and 4, the end surface 4 d of the annular protrusion 4 c is cross-sectional from the exposed surface 6 of the nipple 2 and the sleeve 3 in a state after the diameter reduction of the sleeve 3 shown in FIG. 4. It is inflated and deformed so as to swell slightly in an arc shape.
Although not shown as another example, in the state after the diameter reduction of the sleeve 3, the end surface 4 d of the annular protrusion 4 c is flush with the exposed surface 6 of either the nipple 2 or the sleeve 3. It is also possible to expand and deform like this.

Further, an annular groove 2d is formed at an intermediate position in the axial direction of the first locking portion 2c of the nipple 2, and an annular protrusion is formed on the second locking portion 3c of the sleeve 3 so as to face the annular groove 2d. It is preferable to form the part 3d.
The annular protrusion 4c of the seal material 4 is formed with an engagement recess 4e that fits with the annular protrusion 3d formed in the second locking portion 3c of the sleeve 3, so that the seal material 4 with respect to the sleeve 3 is formed. It is preferable to position the sealing material 4 in the axial direction with respect to the sleeve 3 in the assembled state.
When the nipple 2 is inserted into the connecting end portion of the sleeve 3 and the tube body 1 as indicated by a two-dot chain line and a solid line in FIG. 3, the second sealing portion 4 b of the sealing material 4 is replaced with the first locking portion 2 c of the nipple 2. It is preferable that the annular protrusion 3d of the sleeve 3 is positioned so as to face the annular concave groove 2d of the nipple 2 in the radial direction.
Thereby, along with the diameter reduction deformation of the sleeve 3 shown in FIG. 4, the annular projecting portion 3 d is fitted into the annular concave groove portion 2 d with the annular projecting portion 4 c of the sealing material 4 sandwiched therebetween, and the sleeve with respect to the nipple 2. 3 is prevented from coming off in the axial direction.

In particular, in the example shown in FIGS. 3 and 4, the axial width dimension of the annular protrusion 3 d of the sleeve 3 is set smaller than the axial width dimension of the annular groove 2 d of the nipple 2. Thus, the annular protrusion 4c of the sealing material 4 is prevented from being cut in a state after the diameter reduction deformation of the sleeve 3 shown in FIG.
Although not shown as another example, the axial width of the annular groove 2d and the axial width of the annular protrusion 3d are substantially the same length, and the sleeve 3 shown in FIG. Although the annular protrusion 3d is fitted into the annular concave groove 2d without a gap in the state after the diameter reduction deformation, the annular protrusion 4c of the sealing material 4 may be cut, but with respect to the nipple 2 It is also possible to connect the sleeve 3 so as not to be loose.

Furthermore, the first guide surface 2e of the nipple 2 formed so as to face each other with the through hole 5a of the engagement portion (annular space portion) 5 interposed therebetween, and the second guide surface 3e of the sleeve 3 are connected to each other of the nipple 2 and the sleeve 3. It is preferable to incline in a tapered shape toward the exposed surface 6.
That is, the first guide surface 2e extending from the annular concave groove portion 2d of the nipple 2 toward the exposed surface 6 of the nipple 2, and the second guide extending from the annular protrusion portion 3d of the sleeve 3 toward the exposed surface 6 of the sleeve 3. The surface 3e is inclined and opposed to a substantially parallel taper.

According to the pipe joint structure A shown in FIGS. 3 and 4, the second seal portion 4 b fitted into the through-hole 5 a of the engagement portion (annular space portion) 5 with the diameter reduction deformation of the sleeve 3. The annular protrusion 4c is inflated and deformed so that the front end surface 4d thereof is substantially flush with the exposed surface 6 of the nipple 2 and the sleeve 3, thereby extending over the exposed surface 6 and the end surface 4d of the annular protrusion 4c. There is no dent or step.
Therefore, contamination (contamination) due to accumulation of soot and the like can be prevented.
As a result, there is an advantage that it can be maintained hygienically for a long time.

In particular, when the annular protrusion 3d of the sleeve 3 is fitted in the annular groove 2d of the nipple 2 and positioned in the axial direction, the distal end surface 1c of the tubular body 1 is formed by the first seal surface 4a of the sealing material 4. Is positioned in the axial direction, and the annular protrusion 3d of the sleeve 3 is fixed by the annular concave groove 2d of the nipple 2, so that the tube body 1 and the sleeve 3 can be connected to the nipple 2 without rattling. is there.
Further, as shown in FIGS. 3 and 4, when the first guide surface 2e of the nipple 2 and the second guide surface 3e of the sleeve 3 are inclined in a tapered shape, the diameter of the sleeve 3 is reduced. Accordingly, the annular protrusion 4c of the sealing material 4 is smoothly expanded and deformed, and the contact area between the first guide surface 2e and the second guide surface 3e is increased.
As a result, there is an advantage that airtightness can be further improved.

In the above-described embodiment, the sleeve 3 is a caulking pipe and the caulking machine is tightened in eight directions to reduce the diameter, but the present invention is not limited to this. Tightening that gradually tightens the band-like body by a cylindrical holder that can be reduced in diameter in the radial direction of the tube body 1, a holder that divides the cylindrical body into a plurality of radial directions, a tool rotation operation, etc. An accessory (hose band) or the like may be used.
In this case, the same effect as the previous embodiment can be obtained.

DESCRIPTION OF SYMBOLS 1 Tubing body 1a Inner surface 1b Outer surface 1c Tip surface 1D Reinforcement wire 2 Nipple 2a Annular projection 2b Annular smooth part 3 Sleeve 3a Annular convex part 4 Sealing material 4a First seal surface 4b Second seal part 5 Engagement part (annular space part) )

Claims (4)

A tube having an inner surface that is difficult to expand and deform;
A nipple inserted along the inner surface of the tube;
And a sleeve for pressurizing the diameter direction said tube body deformable provided so as to cover across the tube body on the outside of the nipple,
The tubular body is made of a hard material in which the layer constituting the inner surface is difficult to expand and deform,
An outer peripheral surface of the nipple is formed with a plurality of annular protrusions formed in the axial direction of the nipple so that the diameter gradually increases and inclines in the tube insertion direction, and the nipple is interposed between the plurality of annular protrusions. largest alternately in the axial direction possess an annular smooth portion is a plurality of sets formed, the outer diameter of said plurality of annular smooth portion is set to substantially the inner diameter of the tubular body the same, said plurality of annular projection The outer diameter is set slightly larger than the inner diameter of the tube,
The sleeve is in a state in which the tubular body with the shrink deformation of its is pressurized to diameter reduction direction, the inner surface of the pipe body is pressed against the annular projection of the outer peripheral surface of the nipple closely Uchishu A pipe joint structure characterized by having a surface . The inner peripheral surface of the sleeve, the inner diameter was out direction only impact to the outer surface of the pipe body is an outer diameter substantially the same set of said tube, said outer surface of said tubular body with the shrink deformation of the sleeve The pipe joint structure according to claim 1, further comprising an annular convex portion that bites into the pipe. Between the nipple and the sleeve, provided to be adjacent in the axial direction of the tubular body and the distal end surface of the tubular body, an expansion deformation of the sealing material to the axial direction with the diameter of the sleeve, An engagement portion formed between the nipple and the sleeve so as to be adjacent to the sealing material in the axial direction,
The sealing member includes a first sealing surface closely the front end surface of the tubular body with the reduced diameter of the sleeve to the axial direction of the tubular body, by press-fitting the engaging portion with the diameter of the sleeve claim 1 or 2 wherein the pipe joint structure, characterized in that organic and a second seal portion closely to each of the nipple and the sleeve. The tube body, the pipe joint structure according to claim 1, 2 or 3, wherein further comprising a reinforcing layer formed of reinforcing wire are embedded in the axial direction of the tubular body inside of that.

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