JP2014077495A - Pipe joint structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure airtightness between a pipe body from which a spiral protruded part is protruded and a nipple by bringing the pipe body into close pressure contact with the outer peripheral face of the nipple.SOLUTION: A caulking machine B is used for deforming a caulked pipe 4 with its diameter shrunk. Thus, the pressing force of a second spiral packing part 3b of an elastic sleeve 3 on a spiral recessed part 1b of a pipe body 1 located between the spiral protruded part 1a and itself is set to be higher than the pressing force of a first spiral packing part 3a of the elastic sleeve 3 on the spiral protruded part 1a of the pipe body 1. Even when the pressure of fluid flowing inside the pipe body 1 is changed to be higher, the spiral recessed part 1b of the pipe body 1 is therefore kept in pressure contact with an outer peripheral face 2a of a nipple 2 via a site of the caulked pipe 4 deformed with its diameter shrunk and the second spiral packing part 3b of the elastic sleeve 3.

Description

  The present invention relates to a pipe joint structure used for connecting a pipe body such as a hose formed by protruding a spiral projection on an outer surface to a nipple by tightening a caulking pipe.

Conventionally, in this type of pipe joint structure, the insertion part of the joint is inserted into a hose in which the wire is spirally wound on the outer side, and an elastic sleeve is overlapped with the wire around the end of the hose. Some are placed and the sleeve and hose are radially compressed by a metal ferrule on the outside thereof, and the hose is firmly connected to the joint by pressing the sleeve radially (see, for example, Patent Document 1).
In addition, a nipple inserted into the inner surface of the end of the helically-concave-shaped resin hose having a helical reinforcing body on the outer peripheral surface, and a helically concave-convex shaped portion that can be fitted along the shape of the outer peripheral surface of the hose In addition, the outer peripheral surface of the hose has a spiral concave and convex shape consisting of an elastic packing having a C-shaped cross section on the outer peripheral surface and a holder that is divided into two parts and tightens the elastic packing toward the end of the hose with bolts and nuts. There is also a hose joint that can easily attach the end portion of the resin hose (see, for example, Patent Document 2).

JP 58-042993 A JP 2006-38192 A

By the way, in order to ensure the airtightness between the hose from which the helical wire or the spiral reinforcing body protrudes from such an outer peripheral surface is pressed against the insertion portion or nipple of the joint inserted inside the hose. For this purpose, it is not sufficient to tighten the spiral portion of the hose from which the spiral wire or the spiral reinforcement protrudes toward the insertion portion or nipple of the joint, so that it is not sufficient. Similarly, the spiral recesses formed therebetween need to be tightened and brought into close contact.
However, in the case of Patent Document 1, even if the elastic sleeve and the hose are equally compressed and deformed in the radial direction toward the insertion portion of the joint by the ferrule, the helical wire is strongly tightened by the elastic sleeve. The pressing force of the elastic sleeve against the spiral recess formed between the spiral wires has become much lower than the pressing force of the elastic sleeve against the spiral wires.
In other words, a large pressing force is required for compressive deformation of the spiral wire, and even if the ferrule is compressed and deformed, the pressing force only acts on the wire, and the pressing force against the spiral recess between the wires is low, and the joint It was not possible to ensure airtightness with the plug part.
Therefore, when the pressure of the fluid passing through the inside of the hose (internal pressure) becomes high, a spiral gap is formed between the inner surface portion of the spiral recess formed between the spiral wires and the insertion portion of the joint, There was a problem that the fluid inside the hose leaked outside.
Further, in the case of Patent Document 2, since the spiral uneven portion that fits with the helical reinforcing body of the hose is formed on the inner peripheral surface of the elastic packing, the inner peripheral surface of the elastic packing is tightened by the holder. Can be equally pressed against the helical reinforcement of the hose and the helical recess of the hose formed between the helical reinforcements.
However, even in such Patent Document 2, since the pressing force of the elastic packing against the spiral concave portion of the hose formed between the spiral reinforcing bodies is insufficient, the pressure of the fluid passing through the inside of the hose (internal pressure) is low. When the height is increased, the portion on the inner peripheral surface of the elastic packing where the spiral concavo-convex shape portion is not formed is further compressed and deformed, and the spiral is formed between the inner surface portion of the spiral recess formed between the spiral reinforcements and the nipple. There was a problem that a fluid gap inside the hose could leak to the outside, and sufficient airtightness could not be ensured.
Furthermore, even if the holder divided into two with bolts and nuts is tightened toward the nipple, the entire elastic packing cannot be uniformly reduced in diameter, and the gap generated between the two divided holders provides sufficient airtightness. Sex cannot be secured.

  An object of the present invention is to cope with such a problem, such that the tubular body from which the spiral convex portion protrudes is pressed against the outer peripheral surface of the nipple without a gap to ensure airtightness between the two, etc. It is intended.

  In order to achieve such an object, the present invention includes a tubular body having a spiral convex portion and a spiral concave portion formed between the spiral convex portions on an outer surface, a nipple provided along the inner surface of the tubular body, An elastic sleeve that is elastically deformable provided so as to cover the outer peripheral surface of the nipple with the tubular body interposed therebetween, and a caulking pipe that is provided outside the elastic sleeve and is reduced in diameter by a caulking machine. The sleeve has a first spiral packing portion facing the spiral convex portion of the tubular body and a second spiral packing portion facing the spiral concave portion of the tubular body, and the sleeve of the elastic sleeve with respect to the spiral convex portion The pressing force of the second spiral packing portion of the elastic sleeve against the spiral recess is set to be higher than the pressing force of the first spiral packing portion.

In the present invention having the above-described features, the caulking machine is positioned between the spiral convex portions rather than the pressing force of the first spiral packing portion of the elastic sleeve against the spiral convex portion of the tubular body by deforming the caulking pipe with a caulking machine. Since the pressing force of the second spiral packing part of the elastic sleeve against the spiral concave part of the tube body is set to be high, even if the pressure of the fluid passing through the inside of the tube body changes and becomes high, the diameter deformation of the caulking pipe is reduced. The spiral concave portion of the tube body is maintained in pressure contact with the outer peripheral surface of the nipple at the portion and the second spiral packing portion of the elastic sleeve.
Therefore, the tube body from which the spiral projection protrudes can be pressed against the outer peripheral surface of the nipple without any gap to ensure the airtightness between them.
As a result, the conventional sleeve which compresses the elastic sleeve and the hose in the radial direction toward the insertion portion of the joint by the ferrule, and the spiral uneven portion which fits the spiral reinforcement of the hose on the inner peripheral surface by the holder. Even if the pressure of the fluid passing through the inside of the tube is higher than the conventional one in which the formed elastic packing and hose are tightened toward the nipple, the spiral is formed between the inner surface portion of the spiral recess of the tube and the outer surface of the nipple. Thus, it is possible to reliably prevent the leakage of fluid passing through the inside of the tube body over a long period of time.

It is explanatory drawing which shows the pipe connection structure which concerns on embodiment of this invention, (a) is the partially notched front view before crimping, (b) is the partially notched front view after crimping. It is explanatory drawing which shows the pipe connection structure which concerns on the other Example of this invention, (a) is a partially notched front view before crimping, (b) is the partially notched front view after crimping.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
The pipe joint structure A according to the embodiment of the present invention has a pipe body 1 having a spiral convex part 1a and a spiral concave part 1b formed between the spiral convex part 1a on the outer surface thereof, and an inner face 1c of the pipe body 1. A nipple 2 provided to be inserted, an elastically deformable elastic sleeve 3 provided so as to cover the outer peripheral surface 2a of the nipple 2 with the tube body 1 interposed therebetween, and a caulking machine B provided outside the elastic sleeve 3 A caulking pipe 4 that is deformed to a reduced diameter is provided as a main component.

The tubular body 1 is a flexible hose or tube formed of a deformable soft material such as soft synthetic resin or rubber, and a spiral convex portion 1a is formed on the outer surface thereof so as to project spirally. In addition, a spiral recess 1b is formed between the spiral protrusions 1a.
That is, the outer surface of the tubular body 1 has a concavo-convex shape in which the spiral convex portions 1 a and the spiral concave portions 1 b are alternately formed in the axial direction of the tubular body 1.
As a specific example of the tube body 1, as shown in FIGS. 1 (a), (b) and FIGS. 2 (a), (b), the main body is formed into a single-layered cylindrical shape having a smooth outer surface and an inner surface 1 c. A reinforcing wire having a circular cross-section or a cross-sectional shape similar to the cross-section of the reinforcing wire is spirally wound around the outer surface of the main body so that a part or most of the reinforcing wire protrudes from the outer surface of the tube body 1. As a result, spiral convex portions 1a having a circular cross section and smooth spiral concave portions 1b are alternately and integrally formed in the axial direction of the tube body 1, respectively.
Although not shown as another example, the reinforcing wire wound around the main body of the tubular body 1 can be covered with the same soft material as the main body and integrated. Furthermore, the main body of the tube body 1 is replaced with a multi-layer laminated structure, for example, braided reinforcing yarns such as glass fibers and flame retardant fibers, or a reinforcing wire made of metal or hard synthetic resin is spirally formed. It is also possible to embed in

The nipple 2 is made of a non-deformable rigid material such as a metal such as brass, and is formed in a substantially cylindrical shape having an outer diameter that is substantially the same as the inner diameter of the tube 1, and along the inner surface 1 c of the connecting end portion in the tube 1. By inserting, the outer peripheral surface 2a is arrange | positioned so that the inner surface 1c of a connection end part may be opposed in the tubular body 1. FIG.
The outer peripheral surface 2 a of the nipple 2 is preferably provided with a retaining means that engages with the inner surface 1 c of the tube body 1 in the axial direction.
As a specific example of the nipple 2, as shown in FIGS. 1A, 1B and 2A, 2B, an annular protrusion 2b that bites into the inner surface 1c of the tube body 1, an inner surface 1c of the tube body 1, By forming a plurality of pairs of annular concave grooves 2c that are in pressure contact with each other alternately in the axial direction of the nipple 2 so as to be in the shape of bamboo shoots, a retaining means is configured.
Although not shown as another example, the shape of the retaining means is changed to a bamboo stalk shape, and each annular protrusion 2b is formed in a cross-sectional mountain shape by an inclined surface opposite to the tapered inclined surface, Positioning means for attaching a sealing material such as an O-ring to any one of 2c and bringing the outer peripheral end of the sealing material into pressure contact with the inner surface 1c of the tube 1 or positioning the elastic sleeve 3 and the caulking pipe 4 so that they cannot move. It is also possible to form.

The elastic sleeve 3 is made of an elastically deformable material such as rubber or soft synthetic resin, and is larger than the outer diameter of the tube body 1 so as to face the outer surface of the connection end in the tube body 1, that is, the spiral convex portion 1a. It is formed in a substantially cylindrical shape having an inner diameter. The elastic sleeve 3 includes a first spiral packing portion 3a that faces the spiral convex portion 1a of the tubular body 1 and a second spiral packing portion 3b that faces and contacts the spiral concave portion 1b of the tubular body 1. Yes.
Furthermore, on at least the inner peripheral surface of the elastic sleeve 3, a spiral concave portion 3c that engages with the spiral convex portion 1a formed on the outer surface of the tubular body 1, and a spiral convex portion that engages with the spiral concave portion 1b. Preferably 3d is formed.
As a specific example of the elastic sleeve 3, in the example shown in FIGS. 1A and 1B, spiral concave portions 3 c and convex portions 3 d are alternately formed in the axial direction on the inner peripheral surface of the elastic sleeve 3. By forming the flat portion 3e on the outer peripheral surface of the elastic sleeve 3, a thin first spiral packing portion 3a is formed in the vicinity of the spiral concave portion 3c, and the spiral convex portion 3d is formed in the spiral convex portion 3d. A thick second spiral packing portion 3b is formed.
Further, in the example shown in FIGS. 2A and 2B, spiral concave portions 3c and convex portions 3d are alternately formed in the axial direction on the inner peripheral surface and the outer peripheral surface of the elastic sleeve 3, respectively, and the diameter is changed. By forming back to back in the direction, a thin first spiral packing portion 3a is formed in the vicinity of the spiral concave portion 3c, and a thick second spiral packing portion is formed in the spiral convex portion 3d. 3b is formed.

The caulking pipe 4 is a deformable plastic material such as aluminum, which is compressed and deformed by pressing in the radial direction by a caulking machine B, which will be described later, but is not restored and deformed by a repulsive force from the tube body 1 and the elastic sleeve 3. The sleeve 3 is formed in a cylindrical shape having an inner diameter larger than the outer diameter.
As a specific example of the caulking pipe 4, in the examples shown in FIGS. 1A and 1B and FIGS. 2A and 2B, the axial length is formed to be longer than the axial length of the elastic sleeve 3. doing.
Further, although not shown as another example, the caulking pipe 4 is formed so that the axial length of the caulking pipe 4 is substantially the same as the axial length of the elastic sleeve 3 or shorter than the axial length of the elastic sleeve 3. Is also possible.

On the other hand, the caulking machine B includes a plurality of caulking dies Ba that are disposed so as to surround the caulking pipe 4 and move closer to the outer circumferential surface 4a of the caulking pipe 4 in the radial direction by driving or manually. The plurality of caulking dies Ba are compressed by compressing the outer peripheral surface 4a of the caulking pipe 4 inward by simultaneously pressing each press surface Bb against the outer peripheral surface 4a of the caulking pipe 4 toward the center. Accordingly, the elastic sleeve 3 and the tube 1 are elastically compressed in the radial direction, and the inner surface 1c of the tube 1 is pressed against the outer peripheral surface 2a of the nipple 2 to prevent it from coming off.
The amount of deformation of the caulking pipe 4 by the caulking machine B is smaller than the pressing force of the first helical packing portion 3a of the elastic sleeve 3 against the helical convex portion 1a than the pressing force of the second helical packing portion 3b of the elastic sleeve 3 against the helical concave portion 1b. The pressure is set to be high.
Specific examples of the caulking machine B are disclosed in, for example, a driving caulking machine in which a plurality of caulking dies Ba are moved toward the caulking pipe 4 by a driving source such as a hydraulic device, for example, Japanese Utility Model Publication No. 4-44270. It is possible to use a manual caulking machine.
Further, as the caulking shape of the caulking pipe 4 by the caulking machine B, “an eight-way fastening” for caulking to a substantially regular octagonal cross section in order to uniformly tighten the entire circumference, or a plurality of axial directions to tighten a cylindrical rod. Caulking “clamping” can be used.

According to such a pipe joint structure A according to the embodiment of the present invention, the first crimping of the elastic sleeve 3 that comes into contact with the spiral convex portion 1a of the tubular body 1 by reducing the diameter of the crimping pipe 4 by the crimping machine B. Setting is made such that the pressing force of the second spiral packing portion 3b of the elastic sleeve 3 contacting the spiral recess 1b of the tubular body 1 located between the spiral projections 1a is higher than the pressing force of the spiral packing portion 3a. Is done. Therefore, even if the pressure (internal pressure) of the fluid passing through the inside of the tube body 1 changes and becomes high, the spiral deformation of the tube body 1 is caused by the reduced diameter deformation portion of the caulking pipe 4 and the second spiral packing portion 3b of the elastic sleeve 3. The concave portion 1 b is kept in pressure contact with the outer peripheral surface 2 a of the nipple 2.
Therefore, the tubular body 1 from which the spiral convex portion 1a protrudes can be brought into pressure contact with the outer peripheral surface 2a of the nipple 2 without a gap, thereby ensuring airtightness between the two.
As a result, the elastic sleeve and the hose are compressed in the radial direction toward the insertion part of the joint by the ferrule, and the spiral irregularities fitted to the helical reinforcement body of the hose on the inner peripheral surface by the holder. Even if the pressure (internal pressure) of the fluid passing through the inside of the tubular body 1 is higher than that of the above-described Patent Document 2 in which the elastic packing and the hose formed with the shape portion are tightened toward the nipple, the helical recess of the tubular body 1 is increased. A spiral gap is not formed between the inner surface portion 1bc of 1b and the outer peripheral surface 2a of the nipple 2, and leakage of fluid passing through the inside of the tube body 1 can be reliably prevented over a long period of time.
Next, each embodiment of the present invention will be described with reference to the drawings.

  In the first embodiment, as shown in FIGS. 1A and 1B, the caulking pipe 4 is in contact with the spiral convex portion 1a of the tubular body 1 with the first spiral packing portion 3a of the elastic sleeve 3 interposed therebetween. Depressurization deformation of the caulking pipe 4 by the caulking machine B, having the pressurizing part 4b and the second spiral pressing part 4c contacting the spiral concave part 1b of the tubular body 1 across the second spiral packing part 3b of the elastic sleeve 3 The amount of the second spiral pressurizing portion 4c of the caulking pipe 4 and the elastic sleeve 3 is larger than the amount of deformation (caulking pressure) of the first spiral pressing portion 4b of the caulking pipe 4 and the first spiral packing portion 3a of the elastic sleeve 3. The second helical packing portion 3b is set to have a reduced diameter deformation (caulking pressure).

  In the example shown in FIGS. 1A and 1B, the caulking die Ba of the caulking machine B projects toward the press surface Bb contacting the outer peripheral surface 4 a of the caulking pipe 4 toward the second spiral pressurizing portion 4 c of the caulking pipe 4. It has a spiral projection B1. The press surface Bb of the caulking die Ba excluding the spiral protrusion B1 is formed to be smooth so as to face the second spiral pressing portion 4c of the caulking pipe 4.

  Further, in the first embodiment, a screw portion 5a as a joint portion 5 and a tool engaging portion 5b with which a tool such as a spanner or a wrench engages are formed at the base end of the nipple 2, and the screw portion 5a is connected to another pipe line ( It is connected by screwing to other devices (not shown) or the like.

According to such a pipe joint structure A according to the first embodiment of the present invention, the first spiral pressurizing part 4b and the second spiral pressurizing part 4c of the caulking pipe 4 are respectively deformed by a diameter reduction by the caulking machine B, thereby The spiral recess 1b and the second spiral pressurization part of the tube body 1 rather than the relatively thin first spiral packing part 3a located between the spiral convex part 1a of the body 1 and the first spiral pressurization part 4b. The second spiral packing portion 3b of the relatively thick elastic sleeve 3 positioned between 4c is further compressed and deformed, and the second spiral packing portion 3b is connected to the spiral recess 1b of the tube body 1 with the tube body. The pressure contact force of the first spiral packing portion 3a against the one spiral convex portion 1a is further pressed and the pressure contact state is maintained.
Therefore, the second spiral packing portion 3b of the elastic sleeve 3 can be more closely attached to the spiral recess 1b of the tube body 1 so that it cannot be lifted.
As a result, even if the pressure (internal pressure) of the fluid passing through the inside of the tube body 1 is significantly increased, a spiral gap is formed between the inner surface portion 1bc of the spiral recess portion 1b of the tube body 1 and the outer peripheral surface 2a of the nipple 2. There is an advantage that it is possible to prevent the leakage of the fluid passing through the inside of the tube body 1 more reliably over a long period of time.

  As shown in FIGS. 2 (a) and 2 (b), the second embodiment is such that the elastic sleeve 3 has a thickness greater than that of the first spiral packing portion 3 a facing the spiral convex portion 1 a of the tube body 1. The second spiral packing portion 3b facing the spiral recess portion 1b is formed to have a large thickness, and the inner surface of the second spiral packing portion 3b is formed into the spiral recess portion of the tube body 1 by the diameter reduction deformation of the caulking pipe 4 by the caulking machine B. The configuration that is pressed against 1b is different from the first embodiment shown in FIGS. 1A and 1B, and other configurations are the same as those of the first embodiment.

In the example shown in FIGS. 2A and 2B, in the elastic sleeve 3, the cross-sectional shape of the first spiral packing portion 3a is formed in a thin plate shape, and the cross-sectional shape of the second spiral packing portion 3b is formed in a circular shape. Yes.
Although not shown as another example, the cross-sectional shape of the first spiral packing portion 3a disposed on at least the inner peripheral surface of the elastic sleeve 3 is recessed in a semicircular shape, or the cross-sectional shape of the second spiral packing portion 3b is changed. It is also possible to change to an ellipse or a rectangle.
Further, in the example shown in FIGS. 2A and 2B, the press surface Bb that contacts the outer peripheral surface 4a of the caulking pipe 4 in the caulking die Ba of the caulking machine B has a smooth surface B2.

According to such a pipe joint structure A according to the second embodiment of the present invention, the caulking pipe 4 is reduced in diameter by the caulking machine B, whereby the spiral convex portion 1a of the tubular body 1 and the inner peripheral surface 4d of the caulking pipe 4 are formed. The second spiral packing of the thick elastic sleeve 3 positioned between the spiral concave portion 1b of the tube body 1 and the inner peripheral surface 4d of the caulking pipe 4 rather than the thin first spiral packing portion 3a positioned therebetween. The portion 3b is further compressed and deformed, and the second spiral packing portion 3b is pressed against the spiral recess 1b of the tube body 1 more strongly than the press contact force of the first spiral packing portion 3a against the spiral projection portion 1a of the tube body 1. This pressure contact state is maintained.
Therefore, the second spiral packing portion 3b of the elastic sleeve 3 can be more closely attached to the spiral recess 1b of the tube body 1 so that it cannot be lifted.
As a result, even if the pressure (internal pressure) of the fluid passing through the inside of the tube body 1 is significantly increased, a spiral gap is formed between the inner surface portion 1bc of the spiral recess portion 1b of the tube body 1 and the outer peripheral surface 2a of the nipple 2. There is an advantage that it is possible to prevent the leakage of the fluid passing through the inside of the tube body 1 more reliably over a long period of time.

In the first embodiment and the second embodiment described above, the case where the screw portion 5a and the tool engaging portion 5b are formed as the joint portion 5 at the base end of the nipple 2 is shown, but the present invention is not limited thereto, and the screw portion Instead of 5a and the tool engaging part 5b, although not shown, a flange may be formed and connected to other pipes or other devices via a coupling member such as a cap nut.
Further, the joint portion 5 may be formed separately from the screw portion 5a, the tool engaging portion 5b, and the flange.

DESCRIPTION OF SYMBOLS 1 Tubular body 1a Spiral convex part 1b Spiral concave part 1c Inner surface 2 Nipple 2a Outer peripheral surface 3 Elastic sleeve 3a First spiral packing part 3b Second spiral packing part 4 Caulking pipe 4b First spiral pressurizing part 4c Second spiral pressurizing part B Caulking Machine

Claims (3)

A tube having a spiral protrusion on the outer surface and a spiral recess formed between the spiral protrusions;
A nipple provided along the inner surface of the tube;
An elastically deformable elastic sleeve provided so as to cover the outer peripheral surface of the nipple with the tube interposed therebetween;
A caulking pipe provided outside the elastic sleeve and reduced in diameter by a caulking machine; and
The elastic sleeve has a first spiral packing portion facing the spiral convex portion of the tubular body, and a second spiral packing portion facing the spiral concave portion of the tubular body, and the elastic sleeve with respect to the spiral convex portion The pipe joint structure is set such that the pressing force of the second spiral packing portion of the elastic sleeve against the spiral recess is higher than the pressing force of the first spiral packing portion.   The caulking pipe includes a first spiral pressure part that contacts the spiral convex part of the tubular body with the first spiral packing part of the elastic sleeve interposed therebetween, and a second spiral packing part of the elastic sleeve that sandwiches the second spiral packing part. A second spiral pressurizing portion that contacts the spiral recess of the tubular body, and the second spiral pressurization is less than the amount of deformation of the first spiral pressurization portion and the first spiral packing portion by the caulking machine. The pipe joint structure according to claim 1, wherein the diameter reduction amount of the portion and the second spiral packing portion is set to be large.   In the elastic sleeve, the thickness of the second spiral packing portion facing the spiral concave portion of the tube body is thicker than the thickness of the first spiral packing portion facing the spiral convex portion of the tube body. 2. The pipe joint structure according to claim 1, wherein the inner surface of the second spiral packing portion is pressed against the spiral concave portion of the tubular body by deformation of the crimped pipe formed by the crimping machine.

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