JP5511241B2 - Synthetic resin flexible tube manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing a synthetic resin flexible tube for piping having a fluid flow path therein.

  Conventionally, synthetic resin pipes have been used for water pipes and various gas pipes. When these pipes are fixed at the required pipe installation positions, the pipes are generally adapted to the installation location. In this case, since it is necessary to connect a plurality of straight pipes in a bent state sequentially using an elbow or the like, there is a problem in workability of piping installation. On the other hand, if it is necessary to bend or curve the pipe, if a tube made of a soft synthetic resin is used, there is no need for a bent connection with the elbow or the like, but generally a soft tube is used for the fixed pipe. There are various difficulties, and in many cases, a soft tube cannot be used in relation to the piping installation environment. For example, when it is installed in a narrow space, the soft tube is not bent. There are problems such as bending, a part of which is pressed by another object, and the cross-sectional area of the internal fluid flow path is reduced, and there is also a problem in terms of durability of the tube itself.

  In addition, it has been conventionally known that a metal tube can be bent by a flexible tube such as a bellows-like member. As in the case of use, it is necessary to attach straight pipes to both ends of the flexible pipe by using a joint, which is problematic in terms of workability and is relatively expensive compared to a synthetic resin tube. It is also necessary to consider the rust resistance and corrosion resistance of the flexible tube.

The technical problem of the present invention is that the internal fluid flow path is not narrowed by bending or crushing while having a flexible portion made of soft synthetic resin in a part of a flexible tube made of synthetic resin. The cross-sectional area of the flow path can be secured stably, and there is no need to connect to an elbow or the like for bending or bending, and it can be easily fixed to fit the bent or curved piping installation position. It is providing the manufacturing method of a synthetic resin flexible tube.

In order to solve the above-described problems, according to the present invention, an inner-layer tube made of a flexible soft synthetic resin having a fluid flow path inside, and an outer-layer tube made of a hard or semi-rigid synthetic resin that adheres to the outer periphery thereof. Is formed as a double tube for piping that is in close contact with each other by extrusion molding of a thermoplastic synthetic resin, and a spiral cut is cut into the outer tube at the bent portion of the double tube to make it flexible. A synthetic resin flexible tube manufacturing method is provided, characterized in that a large number of ring-shaped or partial ring-shaped cuts are provided to make it or to make it flexible. A heat-shrinkable protective tube is attached to the outer periphery of the bent portion of the tube having the cut in the outer-layer tube, with the bent portion of the tube being in an unbent straight state or a bent state, and thermally contracted. it can. In addition, a protrusion that reinforces the inner layer tube against expansion and contraction may be provided on the inner surface of the inner layer tube.

According to the present invention described in detail above, the internal fluid flow path is narrowed by bending or crushing while having a flexible portion made of soft synthetic resin in a part of a flexible tube made of synthetic resin. The cross-sectional area of the flow path can be secured stably, and there is no need to connect to an elbow or the like for bending or bending, and it can be easily fixed to fit the bent or curved piping installation position. It is possible to provide a method for manufacturing a flexible tube made of synthetic resin.

It is a principal part front view which shows the 1st structural example of the flexible tube made from a synthetic resin manufactured by the method which concerns on this invention. It is a front view which shows the bending state of the flexible tube made from the same synthetic resin. It is a principal part front view which shows the 2nd structural example of the flexible tube made from a synthetic resin manufactured by the method which concerns on this invention. It is a principal part front view which shows the 3rd structural example of the flexible tube made from a synthetic resin manufactured by the method which concerns on this invention. It is sectional drawing in the AA position in FIG. It is a principal part front view which shows the 4th structural example of the flexible tube made from a synthetic resin manufactured by the method which concerns on this invention. It is sectional drawing in the BB position in FIG. It is sectional drawing in CC position in FIG. It is a fragmentary fragmentary principal part sectional view which shows the modification common to each said structural example of the synthetic resin flexible tube manufactured by the method which concerns on this invention.

1 and 2 show a first structural example of a synthetic resin flexible tube manufactured by the method according to the present invention. This flexible tube 1 made of synthetic resin is used when a necessary number of bent portions or curved portions are formed in a synthetic resin pipe as in the case of connecting a plurality of straight tubes bent using an elbow or the like. Specifically, the inner tube 11 made of a flexible soft synthetic resin having a fluid flow channel 12 inside, and a hard or semi-rigid synthetic material adhered in close contact with the outer periphery thereof. And an outer layer tube 13 made of resin, thereby forming a double tube for piping. The double tube is made of the thermoplastic synthetic resin so that the outer layer tube 13 made of the thermoplastic hard or semi-rigid synthetic resin is attached to the outer periphery of the inner tube 11 made of the thermoplastic soft synthetic resin. This is formed as a double tube for piping closely adhered to each other by extrusion molding.

  And in the part which forms the bending part of this double tube, as shown in FIG. 2, the helical cut | interruption 21 for making it flexible in the outer layer tube 13 is provided. The spiral cut 21 is formed by forming the double tube and then cutting the outer layer tube 13 into a continuous groove shape from the outer surface side to expose the inner layer tube 11. Here, the case where the spiral cut 21 that forms a single bent portion is formed in the double tube is illustrated, but an arbitrary position to bend the double tube that forms a straight tube having a required length. A plurality of them can be provided.

  When the double tube is bent as shown in FIG. 2, the inner layer tube 11 extends in the curved outer portion and the inner layer tube 11 is compressed in the curved inner portion. In the portion where the inner layer tube 11 extends, the total groove width in the spiral cut 21 cut into a groove shape, that is, the total length in the tube length direction of the portion in which the outer layer tube 13 in the inner layer tube 11 is cut is due to the curvature. It is necessary that the elongation of the inner tube 11 can be absorbed within the allowable limit of the elongation of the material. Further, in the portion where the inner layer tube 11 of the inner part of the curve is compressed, the total groove width in the spiral cut 21 cut into the groove shape needs to be larger than the contraction amount of the inner layer tube 11 due to the curve, Therefore, in consideration of these, the groove width, length, and the like of the spiral cut 21 are set. The groove shape of the spiral cut 21 is not limited to a rectangular cross section as shown in the figure, and for example, the outer shape of the outer tube 13 can be a trapezoid.

  The synthetic resin material forming the inner layer tube 11 and the outer layer tube 13 is desirably excellent in adhesion when simultaneous molding is performed. For example, when soft vinyl chloride is used as the material of the inner layer tube 11, As a material for the outer layer tube 13, it is desirable to use similar hard or semi-rigid vinyl chloride. However, each synthetic resin material forming the inner layer tube 11 and the outer layer tube 13 is not limited to these, and can be arbitrarily selected according to the use conditions of the flexible tube made of synthetic resin. If the synthetic resin material forming the inner layer tube 11 and the outer layer tube 13 is not good in bonding properties, an adhesive may be interposed between the two tubes.

In the synthetic resin flexible tube 1, the outer layer tube 13 in the bent portion of the tube is provided with a plurality of ring-like cuts as in the second structural example shown in FIG. 3. 22 can also be configured, and partial ring-shaped cuts 23 and 24 as in the third and fourth structural examples shown in FIGS. Synthetic resin flexible tube of each of these exemplary structure, only the structure of the cuts 22 to 24 differs from the first structure example, the other configurations because not different and were described first structure example For these structural examples, the description of the first structural example is incorporated and omitted.

The second structural example shown in FIG. 3 has a large number of ring-like cuts 22 arranged in a row, and the width of those grooves and the range in which the cuts 22 are cut as a whole are the first structural example. Is equivalent to the range in which the spiral cut 21 is provided.
In the synthetic resin flexible tube 1 according to the second structure example, the outer layer tube 13 is divided at each ring-shaped cut 22, so that a tensile or compressive force is applied in the axial direction of the synthetic resin flexible tube 1. When acting, the force acts directly on the inner tube 11 made of a flexible soft synthetic resin at the bent portion, so that it is desired to use it without such a force acting. The same applies to the synthetic resin flexible tube 1 according to the first structure example.

Further, the partial ring-shaped cut 23 in the synthetic resin flexible tube 1 of the third structural example shown in FIGS. 4 and 5 is separated from the outer tube 13 by the respective cuts 22 in the second structural example. On the other hand, it is connected by two connecting portions 26 facing each other. That is, the partial ring-shaped cut 23 is cut in a semicircular shape in the outer tube 13 between the pair of opposing connecting portions 26. In the synthetic resin flexible tube 1 of this third structural example, the outer layer tube is not divided at the bent portion as in the first and second structural examples. Even when a tensile or compressive force is applied, it can be borne by the connecting portion 26 of the outer tube 13.
The ridges 11 a provided on the inner surface of the inner layer tube 11 reinforce the expansion and contraction of the inner layer tube 11. Such ridges can be provided as appropriate in the first and second structural examples and the fourth structural example described below.

In the third structural example, since the connecting portion 26 is provided, it has strength against tensile or compressive force acting in the axial direction of the synthetic resin flexible tube 1, but on the other hand, the connecting portion The double tube cannot be bent with the side where 26 is present outside and inside the bent portion, and the bending is limited only to the vertical direction in FIG. In addition, the said connection part 26 can also be made into only one place, and, thereby, the freedom degree of bending can be enlarged.

Furthermore, the partial ring-shaped cut 24 in the synthetic resin flexible tube 1 of the fourth structural example shown in FIGS. 6 to 8 is an outer layer tube divided by each cut 22 as in the third structural example. The outer tube 13 divided by each cut is connected by the connecting portion 27 at a position shifted by 90 ° alternately without connecting the connecting portions 13 by the two connecting portions 26 which are linearly opposed to each other. The partial ring-shaped cuts 24 are formed so as to be alternately cut at the left and right positions shown in FIG. 7 and the vertical position shown in FIG. In the synthetic resin flexible tube 1 of the fourth structural example, the bending is not limited to the vertical direction in FIG. 5 as in the third structural example. Although it can be bent in the direction, every other partial ring-shaped cut 24 is involved in the bending, so the bending degree becomes about ½.

The flexible tube 1 made of synthetic resin in each of the above structural examples has sharp corners formed by the cuts on the outer periphery of the bent portions provided with the cuts 21 to 24 in the outer layer tube 13. If it is present in a place where it touches human hands, there is a danger, so a heat-shrinkable protective tube is attached to the part in advance, and the bent part is piped to the required position. After completion of this, it is heat-shrinked by heating it with hot air or the like, and a heat-shrinkable protective tube 29 can be attached as shown in FIG.
The thermal contraction of the heat-shrinkable protective tube 29 attached to the outer periphery of the bent portion may be performed in a straight state where the bent portion is not bent according to the degree of bending of the double tube.

  It can also be said that the synthetic resin flexible tube having the above-described configuration eliminates the need to connect the straight tube with the joint on both sides of the bent portion. If a plurality of bending positions of piping in a device equipped with the synthetic resin flexible tube 1 are known in advance, a plurality of bending cuts can be provided in advance in the double tube according to the positional relationship. Thereby, the piping work of the synthetic resin flexible tube 1 can be remarkably simplified.

DESCRIPTION OF SYMBOLS 1 Synthetic resin flexible tube 11 Inner layer tube 12 Fluid flow path 13 Outer layer tube 21 Spiral cut

Claims (4)

  An inner tube made of flexible soft synthetic resin with a fluid flow path inside and an outer tube made of hard or semi-rigid synthetic resin that adheres to the outer periphery of the inner tube are made by extrusion molding of thermoplastic synthetic resin. A synthetic resin flexible tube characterized in that it is molded as a double tube for close piping, and a spiral cut is formed in the outer tube at the bent portion of the double tube to make it flexible. Manufacturing method.   An inner tube made of flexible soft synthetic resin with a fluid flow path inside and an outer tube made of hard or semi-rigid synthetic resin that adheres to the outer periphery of the inner tube are made by extrusion molding of thermoplastic synthetic resin. It is formed as a double tube for close piping, and a large number of ring-shaped or partial ring-shaped cuts are formed in the outer tube at the bent portion of the double tube to make it flexible. A method of manufacturing a flexible tube made of synthetic resin. A heat-shrinkable protective tube is attached to the outer periphery of the bent portion of the tube having the cut in the outer layer tube, and the bent portion of the tube is in an unbent straight state or a bent state, and thermally contracted.
The method for producing a flexible tube made of synthetic resin according to claim 1 or 2 . On the inner surface of the inner layer tube, a ridge was provided to reinforce the inner layer tube against expansion and contraction.
The manufacturing method of the flexible tube made from a synthetic resin in any one of Claims 1-3 characterized by the above-mentioned .

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