JP2012037033A - Multilayer pressure pipe and multiple pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simultaneously prevent the position displacement of a reinforcing wire material to an inner layer and the generation of bubbles in a pipe with a simple structure.SOLUTION: The reinforcing wire material 2 has a smooth part 2a in the bottom surface facing the outer peripheral surface 1a of the inner layer 1, the friction resistance to between the outer peripheral surface 1a of the inner layer 1 and the smooth part 2a of the reinforcing wire material 2 is increased and they are held such that they can not migrate and gaps are not generated between the outer peripheral surface 1a of the inner layer 1 and the reinforcing wire material 2 by bringing the smooth part 2a into close contact with the outer peripheral surface 1a of the inner layer 1.

Description

  INDUSTRIAL APPLICABILITY The present invention is used as a flexible synthetic resin hose or synthetic resin tube having excellent shape retaining properties, such as a high-pressure air hose, and a conduit for hot water or other fluids or gases. Multi-layer pressure-resistant pipes that include rigid synthetic resin pipes that have rigidity, and multiple pipes that are used when a plurality of fluids are supplied or when a plurality of different flow paths such as a supply flow path and a return flow path are required. Concerning connection pipes.

Conventionally, as this type of multi-layer pressure-resistant tube, a stretched monofilament with a large wire diameter made of thermoplastic resin is formed into a coil spring shape between the inner tube and the outer tube constituting the resin tube, and then heat-treated. There is one in which an object is inserted and wound (for example, see Patent Document 1).
Further, a monofilament having a circular or elliptical cross section as a reinforcing yarn is wound around the outer periphery of the inner resin layer produced by the extrusion device in a mesh shape, and then the outer resin layer is used with the same extrusion device. By covering it, a monofilament is interposed between the resin layer on the inner layer side and the resin layer on the outer layer side, and the portion of the surface area where the resin layer on the inner layer side and the resin layer on the outer layer side are in contact with each other There are some which are fused and fixed to each other during molding (for example, see Patent Document 2).

Japanese Utility Model Publication No. 63-46783 JP 2006-194347 A

However, in such a conventional multi-layer pressure-resistant tube, in the former case, a monofilament is sandwiched and wound between an inner tube (inner layer) and an outer tube (outer layer). Generally, a monofilament is formed by extrusion molding. Since the outer surface is smoothly formed in the axial direction with a circular cross section, and the inner layer and the outer layer are formed into a tubular shape by extruding a material such as a thermoplastic resin, when the monofilament is wound around the outer peripheral surface of the inner layer, the outer layer is The surface of the monofilament may slip and be displaced due to the pressure of the resin or the like when extruding and laminating, whereby the winding pitch of the monofilament may be uneven. A portion where the pitch is widened by this positional shift has a problem that the pressure strength is partially reduced as a tube, and the tube is easily ruptured due to an increase in pressure in the tube.
Further, when a monofilament having a circular cross section is wound around the outer peripheral surface of the inner layer, a substantially triangular gap is formed between the outer peripheral surface of the inner layer and the monofilament having a circular cross section with the line contact portion therebetween. When the outer layer is laminated by extrusion molding so as to cover the outer peripheral surface of the monofilament and the monofilament, the material of the outer layer does not completely enter the substantially triangular gap, and air remains between the inner layer and the outer layer. There was a problem that the adhesive strength of the outer layer was lowered and it was easy to peel off, and the bubble part was easily ruptured by an increase in pressure in the tube.
In addition, when both the inner layer and the outer layer are formed of a transparent or translucent material, there is a problem that irregularly generated bubbles are conspicuous and the commercial value is remarkably lowered.
On the other hand, in the latter case, since a plurality of monofilaments are arranged so as to intersect between the inner layer and the outer layer, the monofilaments overlap each other at the intersection of the mesh and the monofilaments have high rigidity and may overlap each other. Since there is almost no crushing and deformation, the thickness dimension of each intersection part becomes thicker than other parts and partially protrudes, thereby increasing the unevenness of the entire surface of the tube and increasing the gap between the intersection parts. There is a problem that air bubbles are easily generated.
In particular, since the monofilaments overlap each other at the intersection of the mesh, when the other monofilament is overlapped on one monofilament and wound, or when the outer layer is extruded and laminated, the pressure of these monofilaments The surface slips and the winding pitch is likely to be misaligned, and this misalignment may cause the monofilament winding pitch to be non-uniform.

  An object of the present invention is to cope with such problems, and aims to achieve simultaneously prevention of displacement of a reinforcing wire relative to an inner layer and prevention of bubble generation in a pipe with a simple structure. Is.

  In order to achieve such an object, the present invention includes an inner layer, a reinforcing wire wound spirally along the outer peripheral surface of the inner layer, and an outer layer laminated on the outer periphery of the inner layer and the reinforcing wire, The reinforcing wire has a smooth portion on a bottom surface facing the outer peripheral surface of the inner layer, and the smooth portion is disposed so as to be in close contact with the outer peripheral surface of the inner layer.

In the present invention having the above-described features, the reinforcing wire has a smooth portion on the bottom surface facing the outer peripheral surface of the inner layer, and the smooth portion is brought into close contact with the outer peripheral surface of the inner layer, thereby smoothing the outer peripheral surface of the inner layer and the reinforcing wire. Since the frictional resistance between the inner layer and the reinforcing wire is not moved, there is no gap between the outer peripheral surface of the inner layer and the reinforcing wire. Generation prevention can be achieved at the same time.
As a result, compared to the conventional one in which a monofilament with a circular cross section is sandwiched and wound between the inner tube (inner layer) and the outer tube (outer layer) as a reinforcing wire, the reinforcing wire is reinforced by the pressure of the resin when the outer layer is laminated. Therefore, the wrapping pitch of the reinforcing wire can be made uniform, and the pressure resistance strength is not partially reduced. Therefore, the burst due to the pressure increase in the pipe can be surely prevented.
Furthermore, since no gap is formed between the outer peripheral surface of the inner layer and the reinforcing wire, it is possible to reliably prevent the inner layer and the outer layer from being peeled off by bubbles remaining between the inner layer and the outer layer, and the inner layer and the outer layer are both transparent or translucent. Even if it is formed of the above material, bubbles are not noticeable and the commercial value can be maintained high.
Further, since the bottom surface of the reinforcing wire is a smooth portion, the wall thickness of the entire tube can be reduced as compared with the conventional one in which a monofilament having a circular cross section having the same cross sectional area is wound.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which shows the whole structure of the multilayer pressure-resistant tube which concerns on embodiment of this invention, (a) is the external appearance perspective view which notched partially, (b) is a partial expanded longitudinal cross-sectional view. (A)-(d) is a partial expansion longitudinal cross-sectional view which shows the modification of a reinforcing wire. It is explanatory drawing which shows the whole multilayer pressure-resistant pipe | tube structure which concerns on other embodiment of this invention, (a) is the external appearance perspective view which notched partially, (b) is a partial expanded longitudinal cross-sectional view. It is explanatory drawing which shows the whole multilayer pressure-resistant pipe | tube structure which concerns on other embodiment of this invention, (a) is the external appearance perspective view which notched partially, (b) is a partial expanded longitudinal cross-sectional view. It is description which shows the operation | movement at the time of the process in the laser processing apparatus which concerns on other embodiment of this invention. It is description which shows the operation | movement at the time of the process in the laser processing apparatus which concerns on other embodiment of this invention. It is the external appearance perspective view which carried out the partial notch which shows the whole structure of the multiple pipe which concerns on embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
A multilayer pressure-resistant tube A according to an embodiment of the present invention includes a flexible tube such as a flexible hose made of a soft synthetic resin or rubber, a tube having a smaller diameter than the hose, or a rigid tube. A rigid pipe such as a pipe having rigidity made of synthetic resin or the like.
1 to 7, the flexible tube or the rigid tube includes an inner layer 1, a reinforcing wire 2 wound spirally along the outer peripheral surface 1a of the inner layer 1, and the inner layer 1 and the reinforcing wire. 2 and the outer layer 3 stacked on the outer periphery of the outer periphery.

  The inner layer 1 and the outer layer 3 of the flexible tube are made of, for example, a thermoplastic resin such as vinyl chloride resin as a main component, a plasticizer for moderately softening, a stabilizer for preventing deterioration, other lubricants and fillers, Transparent, translucent, or opaque cylinders made by adding processing aids or improving materials in a predetermined ratio or using rubber such as silicone rubber and molding it in a molten state using an extruder, for example, and cooling it Solidified into a shape.

  The inner layer 1 and the outer layer 3 of the rigid tube are made of a thermoplastic hard resin containing an olefin resin such as polypropylene as a main component, a stabilizer for preventing deterioration, other lubricants, fillers, processing aids, improving materials, etc. Is added in a predetermined ratio, and is molded in a molten state by, for example, an extruder and cooled to be solidified into a transparent, translucent, or opaque cylindrical shape.

The reinforcing wire 2 used for the flexible tube or the rigid tube is made of, for example, a monofilament (monofilament) formed of a synthetic resin material such as polyester, nylon (registered trademark), or aramid. By molding in a molten state and cooling it, it is solidified into a linear shape having a predetermined cross-sectional shape.
A monofilament or the like that becomes the reinforcing wire 2 has a smooth portion 2 a on the bottom surface facing the outer peripheral surface 1 a of the inner layer 1, and the smooth portion 2 a is disposed in close contact with the outer peripheral surface 1 a of the inner layer 1.
More specifically, it is preferable that the cross-sectional shape of the monofilament to be the reinforcing wire 2 has the inclined portion 2b that gradually narrows toward the outer layer 3 as a pair of sides that are continuous at both ends in the width direction of the smooth portion 2a. . The inclined portion 2b is formed in a linear shape or an arc shape.
Moreover, as for the monofilament etc. used as the reinforcement wire 2, only one is wound around the outer peripheral surface 1a of the inner layer 1 like a coil spring as shown in FIG. As described in Japanese Patent No. 4465556, a plurality of inner layers 1 are spirally wound at an equal pitch while being arranged in the axial direction, and are adjacent in the axial direction rather than a pitch between a plurality of monofilaments arranged in the axial direction. It is also possible to separate the spiral pitch and partially form a see-through coreless portion in the axial direction.

  And as a manufacturing method of the multilayer pressure-resistant tube A which concerns on embodiment of this invention, as shown, for example to Fig.1 (a), first, the inner layer 1 is extrusion-molded with an extruder, and this is cooled and solidified. After that, the reinforcing wire 2 is supplied toward the outer peripheral surface 1a of the inner layer 1 so that the smooth portion 2a faces the outer peripheral surface 1a, and the reinforcing wire 2 is wound spirally around the inner layer 1, and the outer peripheral surface 1a. Are arranged so that the smooth portion 2a is in close contact with each other. Thereafter, the outer layer 3 is laminated on and covered by the outer periphery of the inner layer 1 and the reinforcing wire 2. Thereby, the layers of the inner layer 1, the reinforcing wire 2 and the outer layer 3 are bonded and integrated.

According to such a multilayer pressure-resistant tube A according to the embodiment of the present invention, as shown in FIGS. 1A and 1B, the smooth portion 2a of the reinforcing wire 2 is in close contact with the outer peripheral surface 1a of the inner layer 1, The frictional resistance between the outer peripheral surface 1a of the inner layer 1 and the smooth portion 2a of the reinforcing wire 2 is increased, the reinforcing wire 2 is held immovably with respect to the outer peripheral surface 1a of the inner layer 1, and the outer peripheral surface 1a of the inner layer 1 Since no gap is formed between the reinforcing wire 2 and the outer layer 3, air is not involved.
Thereby, although it is a simple structure, the position shift of the reinforcement wire 2 with respect to the inner layer 1 and the bubble generation | occurrence | production prevention in a pipe | tube can be achieved simultaneously.

Further, if necessary, between the reinforcing wire 2 and the outer layer 3, as shown in FIG. 3A, a second reinforcing wire 2 'made of a monofilament or the like is spirally wound in the same manner as the reinforcing wire 2. As shown in FIG. 4A, the intermediate layer 4 is laminated between the reinforcing wire 2 and the second reinforcing wire 2 ′, or as shown in FIG. A third reinforcing wire made of monofilament or multifilament with a thinner outer diameter than that of the wire (thin monofilament such as polyester, nylon (registered trademark) or aramid fiber is twisted into a single thread), etc. 5 may be wound in a spiral shape, or the intermediate layer 4 may be laminated between the reinforcing wire 2 and the third reinforcing wire 5 as shown in FIG.
Further, as shown in FIG. 7, a plurality of such multilayer pressure-resistant tubes A according to the embodiment of the present invention are arranged so that each part is in contact with each other in the axial direction, and these contact parts are fixed. It is also possible to manufacture the multi-connected pipe B.
Next, each embodiment of the present invention will be described with reference to the drawings.

  As shown in FIGS. 1A and 1B, in Example 1, a monofilament is spirally wound as a reinforcing wire 2 along the outer peripheral surface 1a of the inner layer 1, and the cross-sectional shape of the monofilament is a smooth portion 2a. As the pair of side sides that are continuous at both ends in the width direction, those in which inclined portions 2b that become gradually narrower toward the outer layer 3 are formed.

In the example shown in FIGS. 1 (a) and 1 (b), as the reinforcing wire 2, a substantially saddle-shaped monofilament having a cross-sectional shape in which the inclined portion 2b is linear and the top side 2c protrudes in an arc shape is used. Yes.
Further, as another example, as a monofilament to be the reinforcing wire 2, the cross-sectional shape thereof is a semicircular shape curved so as to protrude outward as shown in FIG. 2A, FIG. 2) and the slope 2b and the top 2c as shown in FIG. 2 (c) are curved so as to be recessed inward and the top 2c protrudes in an arc shape. It is also possible to use a substantially hat shape, or a substantially mountain shape in which the inclined portion 2b is linear as shown in FIG. 2 (d) and curved so as to be recessed toward the inside of the top side 2c.

  According to the multilayer pressure-resistant tube A according to the first embodiment of the present invention, even if the material of the outer layer 3 is laminated by extrusion molding along the inclined portion 2b of the monofilament that is the reinforcing wire 2, air can be completely involved. In addition, there is an advantage that bubbles can be completely prevented from being generated around the reinforcing wire 2.

In the second embodiment, as shown in FIGS. 3A and 3B, a monofilament is crossed between the reinforcing wire 2 and the outer layer 3 as a second reinforcing wire 2 'in the direction opposite to the spiral direction of the reinforcing wire 2. The configuration arranged in this manner is different from that of the first embodiment shown in FIG. 1, and other configurations are the same as those of the first embodiment shown in FIG.
That is, the monofilament of the reinforcing wire 2 and the monofilament of the second reinforcing wire 2 'are wound in opposite spiral directions and crossed with each other.

In the example shown in FIGS. 3 (a) and 3 (b), monofilaments formed in a substantially bowl shape having the same diameter are used as the reinforcing wire 2 and the second reinforcing wire 2 '.
Further, although not shown as another example, either or both of the reinforcing wire 2 and the second reinforcing wire 2 ′ are formed in a semicircular shape shown in FIG. 2 (a), a substantially trapezoidal shape shown in FIG. 2 (b), It is also possible to use a substantially hat-shaped monofilament shown in FIG. 2C and a substantially mountain-shaped monofilament shown in FIG.

  According to the multilayer pressure resistant tube A according to the second embodiment of the present invention, the reinforcing wire 2 and the second reinforcing wire 2 'are arranged in an intersecting manner, and the tension balance between them is equalized. There is an advantage that twisting can be prevented.

  In Example 3, as shown in FIGS. 4A and 4B, the intermediate layer 4 and the outer peripheral surface 4 a of the intermediate layer 4 are spirally wound between the reinforcing wire 2 and the outer layer 3. The second reinforcing wire 2 'and the smooth portion 2a' of the second reinforcing wire 2 'are arranged so as to be in close contact with the outer peripheral surface 4a of the intermediate layer 4, which is the second embodiment shown in FIG. In contrast, the other configuration is the same as that of the second embodiment shown in FIG.

In the example shown in FIGS. 4A and 4B, the second reinforcing wire 2 'is wound around the outer peripheral surface 4a of the intermediate layer 4 so that the smooth portion 2a' is substantially flush with the outer peripheral surface 4a. ing.
Although not shown as another example, it is possible to arrange the smooth portion 2a ′ so as to bite into the intermediate layer 4 by the winding tension of the second reinforcing wire 2 ′.

According to the multilayer pressure-resistant tube A according to the third embodiment of the present invention, the second reinforcing wire 2 ′ is not affected by the winding shape of the reinforcing wire 2 as compared with the second embodiment shown in FIG. It can be wound at a predetermined pitch. Further, the frictional resistance between the outer peripheral surface 4a of the intermediate layer 4 and the smooth portion 2a 'of the second reinforcing wire 2' is increased and held immovable, and the outer peripheral surface 4a of the intermediate layer 4 and the second reinforcing wire 2 are retained. Since no gap is formed between the smooth portion 2a 'and the second reinforcing wire 2' with respect to the intermediate layer 4, it is possible to simultaneously prevent displacement of the second reinforcing wire 2 'and generation of bubbles in the pipe.
As a result, the displacement of the second reinforcing wire 2 'does not occur due to the pressure of the resin or the like when laminating the outer layer, so that the winding pitch of the second reinforcing wire 2' can be made uniform, thereby partially In addition, since the pressure strength does not decrease, the burst due to the pressure increase in the pipe can be reliably prevented.
Further, since no gap is generated between the outer peripheral surface 4a of the intermediate layer 4 and the second reinforcing wire 2 ', separation of the intermediate layer 4 and the outer layer due to bubbles remaining between the intermediate layer 4 and the outer layer can be reliably prevented. In addition, even when the inner layer, the outer layer, and the intermediate layer 4 are all formed of a transparent or translucent material, bubbles do not stand out and the commercial value can be maintained high.
Further, since the bottom surface of the second reinforcing wire 2 'is the smooth portion 2a, the wall thickness of the entire tube can be reduced as compared with a case where a monofilament having a circular cross section having the same cross sectional area is wound.
Furthermore, as shown in the illustrated example, when the reinforcing wire 2 and the second reinforcing wire 2 ′ are arranged so that their spiral directions are opposite and intersect each other, the reinforcing wire 2 and Since the second reinforcing wire 2 'is arranged in an intersecting manner and the tension balance between them is equalized, there is an advantage that the tube can be prevented from being stretched or twisted.

  In Example 4, as shown in FIGS. 5A and 5B, a multifilament is formed between the reinforcing wire 2 and the outer layer 3 as a third reinforcing wire 5 opposite to the spiral direction of the reinforcing wire 2. The configuration wound spirally so as to intersect is different from the first embodiment shown in FIG. 1, and the other configuration is the same as the first embodiment shown in FIG.

In the example shown in FIGS. 5A and 5B, a substantially saddle-shaped monofilament is used as the reinforcing wire 2.
Although not shown as other examples, the reinforcing wire 2 has a semicircular shape shown in FIG. 2A, a substantially trapezoidal shape shown in FIG. 2B, a substantially hat shape shown in FIG. 2C, and FIG. It is also possible to use a substantially chevron-shaped monofilament shown in (d).

According to such a multilayer pressure-resistant tube A according to Example 4 of the present invention, the reinforcing wire 2 and the third reinforcing wire 5 are arranged in an intersecting manner, the balance of tension between them is equalized, and the entire tube is bent. Thus, when the inner portion of the tube contracts, the multifilament serving as the third reinforcing wire 5 follows, so that the flexibility of the tube can be enhanced while preventing the tube from being stretched or twisted.
As a result, it is possible to obtain a multilayer pressure-resistant tube suitable for movable piping.
Further, when the third reinforcing wire (multifilament) 5 which is thinner than the outer diameter of the monofilament used as the reinforcing wire 2 is used, the reinforcing wire (monofilament) 2 is compared to a case where a plurality of monofilaments are arranged to cross each other. And the third reinforcing wire (multifilament) 5 do not protrude more than the other surface portions, so that there is an advantage that the entire surface of the tube can be smoothed.

  As shown in FIGS. 6 (a) and 6 (b), the fifth embodiment has an intermediate layer 4 between the reinforcing wire 2 and the outer layer 3, and the reinforcing wire 2 along the outer peripheral surface 4a of the intermediate layer 4. Unlike the Example 4 shown in FIG. 5, the structure which has arrange | positioned the 3rd reinforcement wire (multifilament) 5 wound helically so that it may cross | intersect mutually reversely in a spiral direction is different from FIG. This is the same as Example 4 shown in FIG.

In the example shown in FIGS. 6 (a) and 6 (b), the end of the multifilament serving as the third reinforcing wire 5 is wound around the outer peripheral surface 4a of the intermediate layer 4 so as to contact the outer peripheral surface 4a.
Although not shown as another example, it is also possible to arrange the multifilament end so as to bite into the intermediate layer 4 by the winding tension of the third reinforcing wire 5.

  According to the multilayer pressure-resistant tube A according to the fifth embodiment of the present invention, the second reinforcing wire 2 ′ is not affected by the winding shape of the reinforcing wire 2 as compared with the fourth embodiment shown in FIG. There is an advantage that it can be wound at a predetermined pitch.

  In Example 6, as shown in FIGS. 7 (a) and 7 (b), a plurality of multi-layer pressure-resistant tubes A are arranged so that some of them are in contact with each other in the axial direction, and these contact portions are fixed. Unlike the first embodiment shown in FIG. 1, the configuration in which the multi-tube B is manufactured and the reinforcing wires 2 of the multilayer pressure-resistant tubes A are arranged so that the spiral directions thereof are reversed is the other configuration. These are the same as those in the first embodiment shown in FIG.

In the example shown in FIGS. 7 (a) and 7 (b), two multilayer pressure-resistant tubes A are arranged side by side so that their respective circumferential portions are in contact with each other in the axial direction, and are fixed to each other. A monofilament formed in a substantially bowl shape is used as the reinforcing wire 2.
Although not shown in the drawings as other examples, three or more multilayer pressure-resistant pipes A are arranged in such a manner that their respective circumferential portions are in contact with each other in the axial direction and fixed to each other. 2, a semicircular shape shown in FIG. 2 (a), a substantially trapezoidal shape shown in FIG. 2 (b), a substantially hat shape shown in FIG. 2 (c), and a substantially mountain-shaped monofilament shown in FIG. 2 (d). It is also possible to use it.

According to the multiple pipe B according to the sixth embodiment of the present invention, the reinforcing wires (monofilaments) 2 arranged in the adjacent multi-layer pressure-resistant pipes A are arranged so that the spiral directions thereof are reversed. Even if the multi-layer pressure-resistant pipe A is twisted in any direction at the same time, it is supported and held by the respective reinforcing wire (monofilament) 2, so that it is difficult to be crushed and deformed and kink can be prevented.
As a result, there is an advantage that piping can be performed even in a narrow place and workability is good.

In the example shown in FIGS. 1A, 5A, 6A, and 7, only one monofilament serving as the reinforcing wire 2 is wound in a coil spring shape, but this is not limitative. Instead, as described in Japanese Patent No. 4465556, a plurality of monofilaments serving as the reinforcing wire 2 may be wound spirally at an equal pitch while being arranged in the axial direction of the inner layer 1.
Furthermore, in the example shown in FIG. 3A and FIG. 4A, the monofilaments to be used as the reinforcing wire 2 and the second reinforcing wire 2 are wound one by one in a coil spring shape, but the present invention is not limited to this. As described in Japanese Patent No. 4465556, one or both of the reinforcing wire 2 and the second reinforcing wire 2 'are spirally wound at an equal pitch while being arranged in the axial direction of the inner layer 1. May be.
Moreover, in Example 5 shown to Fig.6 (a) (b), although the 3rd reinforcement wire (multifilament) 5 was arrange | positioned along the outer peripheral surface 4a of the intermediate | middle layer 4, it is not limited to this, 3rd The winding position of the reinforcing wire (multifilament) 5 is set between the inner layer 1 and the intermediate layer 4, and the reinforcing wire 2 along the outer peripheral surface 4a of the intermediate layer 4 is opposite to the spiral direction of the third reinforcing wire (multifilament) 5. It may be wound spirally so as to cross each other.

A Multilayer pressure-resistant pipe 1 Inner layer 1a Outer peripheral surface 2 Reinforcing wire 2a Smooth portion 2b Inclined portion 2 'Second reinforcing wire 2a' Smooth portion 3 Outer layer 4 Intermediate layer 4a Outer surface 5 Third reinforcing wire B Multiple pipes

Claims (7)

The inner layer (1), the reinforcing wire (2) wound spirally along the outer peripheral surface (1a) of the inner layer (1), and the outer layer laminated on the outer periphery of the inner layer (1) and the reinforcing wire (2) (3)
The reinforcing wire (2) has a smooth portion (2a) on the bottom surface facing the outer peripheral surface (1a) of the inner layer (1), and the smooth portion (2a) is the outer peripheral surface of the inner layer (1). A multi-layer pressure tube arranged close to (1a).   The reinforcing wire (2) is made of a monofilament, and the cross-sectional shape of the inclined portion is gradually narrowed toward the outer layer (3) as a pair of side sides continuous to both ends of the smooth portion (2a) in the width direction. The multilayer pressure tube according to claim 1, further comprising (2b).   A second reinforcing wire (2 ′) is spirally wound between the reinforcing wire (2) and the outer layer (3), and the reinforcing wire (2) and the second reinforcing wire (2 ′) are respectively spirally wound. The multi-layer pressure-resistant tube according to claim 1 or 2, wherein the multi-layer pressure tubes are arranged so as to cross in opposite directions. An intermediate layer (4) between the reinforcing wire (2) and the outer layer (3), and a second reinforcing wire (2 ′) wound spirally along the outer peripheral surface (4a) of the intermediate layer (4). )
The second reinforcing wire (2 ') has a smooth portion (2a') on the bottom surface of the intermediate layer (4) facing the outer peripheral surface (4a), and the smooth portion (2a ') is used as the intermediate layer. The multilayer pressure tube according to claim 1 or 2, wherein the multilayer pressure tube is arranged so as to be in close contact with the outer peripheral surface (4a) of (4).   A multifilament is spirally wound as a third reinforcing wire (5) between the reinforcing wire (2) and the outer layer (3), and the reinforcing wire (2) and the third reinforcing wire (5) are respectively wound. 3. The multilayer pressure tube according to claim 1 or 2, wherein the multilayer pressure tubes are arranged so that the spiral directions cross oppositely. An intermediate layer (4) between the reinforcing wire (2) and the outer layer (3), and a third reinforcing wire (5) wound spirally along the outer peripheral surface (4a) of the intermediate layer (4) And
The multifilament is used as the third reinforcing wire (5), and the reinforcing wire (2) and the third reinforcing wire (5) are arranged so that their spiral directions intersect in opposite directions. A multilayer pressure tube according to 1 or 2. A plurality of multi-layer pressure-resistant pipes (A) according to claim 1 or 2, arranged in such a way that some of them are in contact with each other in the axial direction, and a multiple pipe (B) in which these contact parts are fixed,
A multi-passage pipe characterized in that the reinforcing wire (2) of the multilayer pressure-resistant pipe (A) is arranged so that the spiral directions thereof are reversed.

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