JP2005214425A - Synthetic resin-made hose having joint part in both end parts - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a synthetic resin-made hose provided with a small diameter joint part in one end part and a large diameter joint part connected with the small diameter joint part in the other end part. <P>SOLUTION: This synthetic resin-made hose having flexibility is manufactured by winding a soft synthetic resin-made beltlike member in a half-melted condition spirally while overlapping the beltlike members on a molding rotary shaft. The joint part 3 having larger inside diameter than inside diameter of a hose main body 1 is integrally formed in one end part of the hose main body 1 formed in such a way that it has the same diameter over the whole length on its inner peripheral face. The small diameter joint part 2 having the same inside diameter as inside diameter of the hose main body 1 and having such a diameter that can be internally fitted into the large diameter joint part 3 is integrally formed in the other end part of the hose main body 1. These large diameter joint part 3 and small diameter joint part 2 are constituted in such a mnanner that inner and outer peripheral faces are formed into smooth faces over the whole length. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a flexible soft synthetic resin hose having joints integrally provided at both ends.

  As a soft synthetic resin hose such as vinyl chloride resin used for water supply and drainage hoses, watering hoses, etc., conventionally, as shown in FIG. 12, the inner peripheral surface is flat with the same diameter over the entire length. A hose in which a reinforcing spiral protrusion 52 is integrally provided on the outer peripheral surface of a tube wall 51 formed on the surface is widely used.

In order to manufacture such a soft synthetic resin hose, when a semi-molten synthetic resin strip having a certain width is spirally wound around a molding rotating shaft while being extruded from a forming nozzle, a preceding strip shape is formed. The tube wall 51 is formed by superimposing the other side portions of the following strip-shaped material on one side of the material and integrally welding them, and the core wire material is spirally wound on the preceding belt-shaped material. It is manufactured by forming a reinforcing spiral ridge 52 having a core wire material therein by winding a subsequent belt-like material in a spiral shape so as to cover the core wire material.
JP 2000-266245 A

  However, when a soft synthetic resin hose manufactured by this method is cut into predetermined lengths to obtain a drainage hose of a certain length, this hose has an inner peripheral surface over the entire length between the openings at both ends. Are formed on a flat surface having the same diameter, the hoses cannot be directly connected to each other. For this reason, a connection port member such as a nipple is inserted and fixed to the opening end of the hose, but the water passage hole penetrating through the center of the connection port member is formed to be smaller than the inner diameter of the hose. As a result, there arises a problem that the flow resistance increases and smooth drainage and water supply cannot be performed.

  Further, if the end portion of the connection port member is formed to have a large diameter and is attached to the outer peripheral surface of the open end portion of the soft synthetic resin hose, the central water passage hole of the connection port member is made soft. Although it can be formed to have a diameter substantially equal to the inner diameter of the synthetic resin hose, the outer surface of the soft synthetic resin hose is provided with the reinforcing spiral protrusion across the both ends. When the ends are connected to each other, the reinforcing spiral ridge is fitted in the inner peripheral surface of the end of the connection port member, and water leakage occurs through the spiral groove of the spiral ridge. After embedding a suitable filler and forming the outer peripheral surface of the hose end to a flat surface, the connection port member must be fitted and fixed, and it takes time to install the connection port member. However, there is a problem that the cost becomes high.

  The present invention has been made in view of such problems, and the object of the present invention is to enable connection in a watertight and smooth manner without using a joint member such as a connection port member. It is in providing the flexible synthetic resin hose which has flexibility.

  In order to achieve the above object, a synthetic resin hose having joint portions at both ends according to claim 1 of the present invention is obtained by spirally winding a semi-molten soft synthetic resin strip on a molding rotating shaft. A flexible synthetic resin hose that is manufactured, and has an inner peripheral surface formed on a smooth surface having the same diameter over the entire length, at one end of a soft synthetic resin hose main body having a predetermined length. A joint portion whose inner diameter is larger than the inner diameter of the hose main body is integrally formed by continuous spiral winding of the semi-molten soft synthetic resin strip and the other end has an inner diameter of the hose main body. A small-diameter joint portion having the same diameter as the inner diameter and having a diameter that can be fitted into the large-diameter joint portion is integrally formed by continuous spiral winding of the semi-molten soft synthetic resin strip.

  In the synthetic resin hose, the invention according to claim 2 forms a flexible synthetic resin hose main body having flexibility by integrally providing a reinforcing spiral protrusion on the outer peripheral surface of the thin wall of the tube. The large-diameter joint portion and the small-diameter joint portion formed at both ends of the hose main body are characterized in that the inner and outer peripheral surfaces thereof are formed into smooth surfaces over the entire length.

  According to the soft synthetic resin hose of the present invention, a flexible synthetic resin hose manufactured by spirally winding a semi-molten soft synthetic resin strip on a molding rotating shaft, A joint portion having an inner diameter larger than the inner diameter of the hose main body is formed at one end of the soft synthetic resin hose main body having a predetermined length and a smooth surface having the same diameter over the entire length. It is integrally formed by continuous spiral winding of a strip material made of soft synthetic resin in a semi-molten state, and the inner diameter of the other end is the same as the inner diameter of the hose main body, and the outer diameter is fitted into the large-diameter joint. Since the small-diameter joint portion having a possible diameter is integrally formed by continuous spiral winding of the above-mentioned semi-molten soft synthetic resin strip material, a separate joint member is required when connecting the hoses together Not in the large diameter joint of one hose It can be easily done by inserting the small-diameter joint part of the hose, and the smooth outer peripheral surface of the small-diameter joint part is in close contact with the smooth inner peripheral surface of the large-diameter joint part and has a watertight connection structure. can do.

  In addition, it is possible not only to form a long hose excellent in flexibility by inserting the joints of large and small diameters facing each other in order, but also the inner diameter of the small diameter joint part is a hose. Since it is formed to have the same diameter as the inner diameter of the main body, it can be circulated smoothly over the entire length with almost no fluid flow resistance. Further, this hose has a flexible hose main body and large and small joints provided at both ends of the hose main body in a spiral winding of a semi-molten soft synthetic resin strip on a molding rotating shaft. Therefore, it is possible to provide a soft synthetic resin hose which is suitable for mass production and has a uniform and excellent strength without weak parts.

  In the above-mentioned synthetic resin hose, the invention according to claim 2 is superior to the thin-walled tube wall part because the hose main body is formed by integrally providing the reinforcing spiral protrusion on the outer peripheral surface of the thin-walled tube wall. The hose does not deform into a flat shape by the reinforcing spiral ridges, and the cross-section is always kept in a circular shape so that a good fluid flow is possible. The formed large-diameter joint portion and small-diameter joint portion have inner and outer peripheral surfaces formed on a smooth surface over the entire length, so that the hoses can be connected to each other in a water-tight state as described above, and other hoses. Connection to the tube and the tube can also be performed in a watertight state.

  Next, a specific embodiment of the present invention will be described with reference to the drawings. FIG. 1 has flexibility made of an olefin resin such as EVA resin, polyethylene, polypropylene resin, or a soft synthetic resin such as vinyl chloride resin. The synthetic resin hose A is a synthetic resin hose A formed by integrally forming a small-diameter joint portion 2 and a large-diameter joint portion 3 made of the same synthetic resin material at both ends of the synthetic resin hose main body 1. The reinforcing spiral ridge 5 is integrally formed on the outer peripheral surface of the tube wall 1a, the inner peripheral surface of which is formed on the smooth surface 4 having the same diameter over the entire length. Is formed several times thicker than the tube wall 1a.

  Further, these large and small diameter joint portions 2 and 3 are formed so that the inner and outer peripheral surfaces of the large and small diameter joint portions 2 are smooth and smooth, and the small diameter joint portion 2 has an inner diameter of the tube wall 1a of the hose main body 1. The large-diameter joint portion 3 is formed so as to be equal to the inner diameter, and the small-diameter joint portion 2 is formed so that the small-diameter joint portion 2 can be inserted into the large-diameter joint portion 3.

  The reinforcing spiral ridge 5 provided integrally on the outer peripheral surface of the tube wall of the hose main body 1 is made of polypropylene, polyethylene, or hard, with a circular or elliptical cross section in the hollow spiral ridge portion 5a made of the same synthetic resin as the hose main body 1. A synthetic resin reinforcing core wire 5b having appropriate elasticity and hardness, such as vinyl chloride, is internally provided in a continuous spiral shape.

  Further, inside the large and small diameter joint portions 2 and 3, a small diameter reinforcing core wire 5b ′ continuous from the synthetic resin reinforcing core wire 5b forming the reinforcing spiral protrusion 5 of the hose main body 1 is provided on the hose main body 1. It is embedded in the spiral form from the edge part.

  Next, the manufacturing method of the synthetic resin hose A configured as described above will be described with reference to FIGS. 2 to 5. As shown in FIG. 2, the soft synthesis of a semi-molten soft vinyl chloride resin or the like having a certain width is performed. As is well known, the resin strip 11 is extruded from the first molding nozzle 21 on the base end portion of the metal molding rotating shaft 20 and on the one side portion of the preceding strip member portion 11a. The tube wall 1a is formed by spirally winding at a constant pitch while overlapping and welding the opposing side parts together, and in the course of forming the tube wall 1a, the second molding nozzle 22 A reinforcing core wire 5b made of a synthetic resin such as polyethylene, polypropylene, or hard vinyl chloride in a semi-molten state having a constant diameter is spirally wound on the above-described synthetic resin strip-shaped material portion 11a that has been wound first, and this reinforcing core wire 5b The above winding By covering the synthetic resin strip 11b, a hollow spiral ridge portion 5a in which a reinforcing linear object 5b is housed on the outer peripheral surface of the tube wall 1a is formed.

  In this way, by winding the semi-molten soft synthetic resin strip 11 on the rotating shaft 20 in a spiral manner, a hollow helix with the synthetic resin reinforcing core wire 5b and the reinforcing core wire 5b provided on the outer peripheral surface of the tube wall 1a. While producing the synthetic resin hose main body 1 formed by forming the reinforcing spiral ridge 5 composed of the ridge portion 5a, the synthetic resin hose main body 1 is continuously moved forward on the molding rotating shaft 20 toward the tip. Send it out. When the synthetic resin hose main body 1 having a predetermined length is formed, as shown in FIG. 3, the end of the hose main body 1 has a thickness several times that of the tube wall 1a and has an inner diameter of the pipe. A small-diameter thick cylindrical portion 2 ′ having a length twice as long as the small-diameter joint portion 2 having the same diameter as the inner diameter of the wall 1a and a smooth inner and outer peripheral surface is formed continuously.

  The formation of the small-diameter thick cylindrical portion 2 'is the thickness of the semi-molten synthetic resin strip 11 extruded from the first molding nozzle 21 following the formation of the synthetic resin hose main body 1 having the predetermined length. The thick synthetic resin strip 11 'is continuously wound from the rear end of the hose main body 1 onto the molding rotary shaft 20, and then onto one side of the strip wound on the previously wound strip. The other side portion of the belt-like material portion to be rolled is spirally wound at the same pitch while being polymerized and welded.

  Further, the above-mentioned semi-molten steel 22 is extruded from the second molding nozzle 22 while molding the synthetic resin reinforcing core wire 5b in a semi-molten state into a small diameter 5b ', and the small-diameter reinforcing core wire 5b' is wound around the molding rotating shaft 20 By being fed spirally between the thick synthetic resin strips 11 ′ and 11 ′ in a state, they are embedded in the small diameter thick cylindrical portion 2 ′ formed by these small diameter thick cylindrical portions 2 ′. The outer peripheral surface of the small-diameter thick cylindrical portion 2 ′ is pressed by the rolling roller 24 to form a smooth surface.

  Thus, since the small-diameter thick cylindrical portion 2 ′ is formed on the molding rotary shaft 20, its inner diameter is the same as the outer diameter of the molding rotary shaft 20, ie, the same diameter as the inner diameter of the hose main body 1. The

  Subsequent to the formation of the small-diameter thick cylindrical portion 2 ', as shown in FIG. 4, the thickness of the semi-molten soft synthetic resin strip 11 extruded from the first molding nozzle 21 is reduced again and the same as described above. Then, the flexible synthetic resin strip 11 is spirally polymerized and welded onto the rotating shaft 20 to form a hose main body 1 having a predetermined length continuous with the small diameter thick cylindrical portion 2 '. At this time, the reinforcing spiral wire 5b pushed out from the second forming nozzle 22 is also spirally wound between the soft synthetic resin strips 11 and 11 while forming a large diameter to form the reinforcing spiral ridge 5 in the same manner as described above. To do.

  Next, after the hose main body 1 having a predetermined length is formed, the process proceeds to a process for forming a large-diameter thick cylindrical portion 3 ′ continuous with the hose main body 1. As shown in FIGS. 5 and 6, the large diameter thick cylindrical portion 3 ′ is formed so that the inner diameter is equal to the outer diameter of the molding rotary shaft 20 and the outer diameter is equal to the outer diameter of the small diameter thick cylindrical portion 2 ′. This is carried out by using a large-diameter thick cylindrical portion molding member 6 having a short cylindrical shape which is substantially equal and has the same length as that of the small-diameter thick cylindrical portion 2 ′ or a slightly longer constant thickness.

  This molded member 6 is made of rubber, and the outer peripheral surface of the front and rear opening is formed into tapered surfaces 61 and 62 that gradually become smaller in diameter toward the opening end, and a part of it is cut over the entire length. The opposing end faces 63 and 64 that are elastically joined to each other are formed by this cutting.

  In order to mount the molding member 6 formed in this way on the molding rotary shaft 20, the opposing end faces 63, 64 of the molding member 6 are expanded in the direction of separating and are formed on the base end portion of the molding rotary shaft 20. After covering, the opposing end surfaces 63 and 64 are brought into close contact with the original state by the elastic restoring force, and are loosely fitted and attached so as to be slidable in the length direction of the molding rotary shaft 20.

  The molding member 6 mounted on the base end portion of the molding rotary shaft 20 is moved on the molding rotary shaft 20 by the feed rollers 23 and 23 disposed outside the base end portion of the molding rotary shaft 20. As shown in FIG. 5, the front end face is joined to the rear end of the synthetic resin hose main body 1 which is fed forward to the hose manufacturing section 21 and manufactured to a predetermined length as shown in FIG. Then, the semi-molten synthetic resin strip 11 extruded from the first molding nozzle 21 and manufacturing the rear end portion of the synthetic resin hose main body 1 is formed from the rear end of the hose main body 1 of the molded member 6. Continuously spirally wound around the outer peripheral surface of the front end.

  At this time, the semi-molten synthetic resin strip 11 extruded from the first molding nozzle 21 is similarly extruded when the small-diameter thick cylindrical portion 2 ′ is formed. The material 11 'is wound around the outer peripheral surface from the outer peripheral tapered surface 61 at the front end of the molded member 6 in a continuous spiral shape, and has a large diameter and thick cylindrical portion 3' having a thickness several times that of the tube wall 1a of the hose main body 1. Is formed on the outer peripheral surface of the molded member 6 and a semi-molten synthetic resin reinforcing core wire 5b is extruded from the second molding nozzle 22 while being molded into a small diameter 5b 'and spirally wound around the molded member 6. Embedded in a semi-molten synthetic resin strip 11 '.

  That is, when the semi-molten synthetic resin strip 11 'is spirally wound around the outer peripheral surface of the molded member 6, the strip following on one side of the leading strip portion is the same as in the manufacture of the hose main body 1. The opposite side parts of the material parts are overlapped and welded together, wound spirally at a constant pitch, and the small-diameter synthetic resin reinforcing core wire 5b 'is inserted between these belt-like material parts. However, since the strip 11 'is thick, the reinforcing core wire 5b' has a smaller diameter than that of the reinforcing spiral protrusion 5, so that, similarly to the formation of the small-diameter thick cylindrical portion 2 ', The reinforcing core wire 5b ′ is embedded in the strip-shaped material portion so that the outer diameter of the large-diameter thick cylindrical portion 3 ′ formed by spiral winding of the strip-shaped material 11 ′ does not protrude spirally. It will be in the state embedded in the thick cylindrical part 3 '. Further, the outer peripheral surface of the large-diameter thick cylindrical portion 3 ′ is pressed by the rolling roller 24 to be formed into a flat surface.

  In this way, a thick synthetic resin strip 11 'in a semi-molten state is spirally wound around the outer peripheral surface of the molding member 6 to form a large-diameter thick cylindrical portion 3' having a constant thickness while hose on the molding rotating shaft 20. When the thick strip 11 'reaches the rear end tapered surface 62 of the forming member 6 as the forming member 6 moves forward integrally with the main body 1, the forming rotary shaft 20 starts again from above the tapered surface 62. A thin soft synthetic resin strip 11 is continuously spirally wound on the hose main body 1 having a predetermined length. At this time, the semi-molten strip 11 from the first molding nozzle 21 spirally wound on the molding rotary shaft 20 from the rear end tapered surface 62 of the molding member 6 is again pushed out while the thickness thereof is reduced and As shown in FIG. 7, the hose main body 1 having the reinforcing spiral protrusion 5 is formed on the outer peripheral surface while extruding the semi-molten reinforcing core wire from the second forming nozzle 22 as the original large-diameter core wire 4b. .

  Then, after the hose main body 1 having a predetermined length is formed, the small diameter thick cylindrical portion 2 'is formed again on the molding rotating shaft 20 as shown in FIG. After the hose main body 1 having a predetermined length is formed following the section 2 ′, a large-diameter thick cylindrical section 3 ′ is continuously formed at the rear end of the hose main body 1. That is, every time the hose main body 1 having a predetermined length is formed, the small diameter thick cylindrical portion 2 ′ and the large diameter thick cylindrical portion 3 ′ are alternately formed. Either the small-diameter thick cylindrical portion 2 ′ or the large-diameter thick cylindrical portion 3 ′ may be formed first.

  The hose main body 1 and the large and small-diameter thick cylindrical portions 2 ′ and 3 ′ continuously formed on the molding rotary shaft 20 are fed to the distal end side of the molding rotary shaft 20 to the outside of the molding rotary shaft 20. 7 and FIG. 7 by the rotary cutting blade 26 which is cooled and hardened by the cooling water sprayed from the arranged cooling device 25 and further advanced and arranged on the outer peripheral side of the front end side of the molding rotary shaft 20. As shown in FIG. 8, the central portion in the length direction of the small diameter thick cylindrical portion 2 ′ and the large diameter thick cylindrical portion 3 ′ reaching the rotary cutting blade 26 is cut over the entire circumference.

  The small-diameter thick cylindrical portion 2 ′ and the large-diameter thick cylindrical portion 3 ′ are cut to the depth reaching the inner peripheral surface by the rotary cutting blade 26. Therefore, the small-diameter thick cylindrical portion 2 ′ and the large-diameter thick cylindrical portion 2 ′ are cut. The thick cylindrical portion 3 'has a small diameter joint portion 2 consisting of a small diameter thick cylindrical portion 2' divided into one end of a constant length hose main body 1 in two parts and a large diameter wall thickness divided into the other end. A synthetic resin hose A having a large-diameter joint portion 3 composed of a cylindrical portion 3 ′ is sequentially manufactured.

  Further, when the hose main body 1 is pulled out from the molding rotary shaft 20 after the large-diameter thick cylindrical portion 3 'is divided into two parts, as shown in FIG. Since the molded member 6 remains in a state in which one half is inserted and the other half is protruded from the open end of the large-diameter joint portion 3, the molded member 6 is removed from the large-diameter joint portion 3, Again, it is supplied to the hose manufacturing section on the base end side of the molding rotary shaft 20 and covered on the molding rotary shaft 20 in the same manner as described above, and used for molding the large-diameter thick cylindrical portion 3 ′.

  As shown in FIG. 1, the synthetic resin hose A manufactured as described above has a reinforcing spiral on the outer peripheral surface of the tube wall 1a formed on the smooth surface 4 having the same inner diameter over the entire length. The hose main body 1 having a predetermined length formed integrally with the ridge 5 has an inner diameter that is the same as the inner diameter of the tube wall 1a and a smooth inner and outer surface, and is several times the tube wall 1a. The small-diameter joint portion 2 having a thickness of 1 mm is integrally provided, and the other end is formed with a smooth inner and outer peripheral surface with an inner diameter substantially the same as the outer diameter of the small-diameter joint portion 2 and the tube wall 1a. A large-diameter joint portion 3 having a thickness several times that is integrally provided, and further, a synthetic resin reinforcing core wire 5b in which the reinforcing spiral protrusion 5 is formed inside the large- and small-diameter joint portions 2 and 3. The small-diameter reinforcing core wire 5b ′ has a structure embedded in a spiral shape in a state of being continuous from the hose main body 1 side.

  As an example of the use of the flexible synthetic resin hose A having such a configuration, as shown in FIG. 10, in order to connect the hoses A and A to each other, a large-diameter joint portion of one hose A is used. 3 can be carried out by inserting the small diameter joint portion 2 of the other hose A, and a hose having a different structure or a rigid tube body is connected to the large and small diameter joint portions 2 and 3 of the hose A. It is also possible to do.

  In the method of manufacturing the soft synthetic resin hose A, the molded member 6 for forming the large-diameter thick cylindrical portion 3 'is cut partly over the entire length to form opposed end surfaces 63 and 64 that are in close contact with each other. However, it is formed so as to be mounted on the forming rotary shaft 20 by expanding the space between the opposed end surfaces 63 and 64, but as shown in FIG. Half-cylindrical molding member half piece 6A and molding member which are formed on tapered surfaces 61 'and 62' having a double length and gradually decreasing in diameter as the outer peripheral surfaces of both front and rear end portions are directed toward the end surface A short cylindrical shaped member 6 ′ having an inner diameter equal to the outer diameter of the molded member 6 may be formed from the other half piece 6B. In this case, the molded member half piece 6A and the molded member other half piece 6B are not limited to rubber, but may be made of metal such as aluminum or aluminum alloy.

  Several small-diameter engagement holes 65 are formed on either one of the joining end faces 63 and 64 of the molded member half piece 6A and the other half piece 6B, and the other projections are detachably fitted into the engagement holes 65. A body 66 is provided, and the molding member one half piece 6A and the other half piece 6B are put on the outer peripheral surface of the base end portion of the molding rotating shaft 20 in a bellows-like manner, and the projection body 66 is inserted into the engagement hole 65. As a result, the joining end faces 63 and 64 are joined together and assembled into a short cylindrical shaped member 6 ′ that can be slidably moved on the shaping rotary shaft 20. A method for forming the large-diameter thick cylindrical portion 3 ′ formed on the outer peripheral surface of the molded member 6 ′, a method for forming the hose main body 1 having a predetermined length on the molding rotary shaft 20, and a small-diameter thick cylindrical portion 2 ′. Since the forming method is the same as in the above embodiment, the description thereof is omitted.

FIG. 3 is a partially cut-away vertical side view of the soft synthetic resin hose of the present invention. The simplified side view which sectioned a part of state which forms the hose main part. The simplified side view which sectioned a part which shows the state which has formed the small diameter thick cylindrical part. The simplified side view which shows the formation state of a hose main body from a small diameter thick cylindrical part. The simplified side view which sectioned a part which shows the state which has formed the large diameter thick cylindrical part. The simplified perspective view of a forming member. The side view which shows the state which divides a small diameter thick cylindrical part after cooling and cooling. The side view which shows the state which divides a large diameter thick cylindrical part after cooling and cooling. The side view which shows the state which extracts a molded member from a large diameter coupling part. The simplified side view which shows an example of a use condition. The disassembled perspective view of the shaping | molding member which has another structure. The side view which shows a prior art example.

Explanation of symbols

A Soft synthetic resin hose 1 Hose main body 2 Small diameter joint
2 'Small diameter thick cylindrical part 3 Large diameter joint part
3 'Large diameter thick cylindrical part 5 Reinforced spiral ridge
11 Thin-walled soft synthetic resin strip
11 'Thick and soft synthetic resin strip
20 Molding axis

Claims (2)

A flexible synthetic resin hose manufactured by spirally winding a semi-molten soft synthetic resin strip on a molding rotating shaft, and has a smooth inner surface having the same diameter over its entire length. A continuous portion of the semi-molten soft synthetic resin strip-like material is formed at one end of the soft synthetic resin hose main body having a predetermined length formed on the surface with a joint portion having an inner diameter larger than the inner diameter of the hose main body. A semi-molten small-diameter joint portion that is integrally formed by spiral winding and has an inner diameter that is the same as the inner diameter of the hose main body and an outer diameter that can be fitted in the large-diameter joint portion. A synthetic resin hose having joints at both ends, which are integrally formed by continuous spiral winding of a soft synthetic resin strip in a state. The flexible soft synthetic resin hose main body has a reinforcing spiral protrusion integrally formed on the outer peripheral surface of the thin wall of the tube, while the large diameter joint portion and the small diameter formed at both ends of the hose main body. 2. The synthetic resin hose having joint portions at both ends according to claim 1, wherein the joint portion is formed so that the inner and outer peripheral surfaces thereof are smooth surfaces over the entire length.

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