JPH11280961A - Resin hose having excellent resistance to pressure deformability - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain a hose which is flexible and reduced in elongation when being pressurized by providing a bellows shape at least in a part of the hose, and making the section of an angled part of the bellows shape oval or elliptical. SOLUTION: A hose has a bellows structure at least partially, and the section of an angled part of the bellows part is oval or elliptical. The smaller the angled part height ratio (h1/h2) of the angled part height h1 in the minor axis direction to the angled part height h2 in the major axis direction is, the smaller the elongation of the hose while being pressurized is, which is effective for improvement in pressure and deformation tightness. Preferably the angled part height ratio is 0.75 or less. When it is too small, the flexibility is easily damaged. Accordingly, preferably it is at least 0.1 to more. the change amount in the direction of an elliptical axis of the adjacent angled parts is 3 degrees, preferably 15 degrees. Thus, excellent flexibility and resistance to pressure deformability can both be provided together.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hose which is used for transporting a chemical solution and pneumatically and which is flexible and has excellent resistance to pressure deformation.

[0002]

2. Description of the Related Art Various pressure hoses such as hydraulic hoses, hydraulic hoses and pneumatic hoses, vacuum hoses, cooler piping hoses, fuel piping tubes, brake tubes, air conditioner piping tubes used in the automobile industry,
Many hoses and tubes are used for radiator hoses and control cable liners. In particular, various hoses and tubes used in the automobile industry are required to have extremely high performance such as high strength at high temperatures, long-term heat resistance, chemical resistance, gas barrier properties, and flexibility. In recent years, bellows-shaped hose tubes have been used because of the workability of components, vibration absorption, and flexibility in component layout.

However, when internal pressure is applied to a normal bellows hose, the hose tube extends in the axial direction, and the fixed portion of the hose tube deforms in an arcuate manner, causing a problem of contact with other parts. For this reason, it is required that the elongation of the hose / tube under an internal pressure load be reduced as much as possible.

[0004]

SUMMARY OF THE INVENTION The present invention has been achieved as a result of studying the improvement of the above-mentioned problems as a problem, and it is an object of the present invention to provide a hose which is flexible and has a low elongation under pressure.・ Provide a tube.

[0005]

That is, the present invention provides a hose having a pressure-resistant deformability characterized in that at least a part of a hose has a bellows shape, and a cross section of a peak portion of the bellows shape is an ellipse or an ellipse. An excellent resin hose, an elliptical or elliptical shape having a bellows-shaped peak cross section, has a peak height (h
1) and the peak height ratio (h1 / h1) of the peak height (h2) in the long axis direction.
h2) is 0.75 or less, and the resin hose excellent in the resistance to deformation described above, wherein the elliptical or elliptical cross section of the bellows-shaped peak portion is formed between adjacent peak portions. The resin hose excellent in pressure-resistant deformation resistance described above, wherein the phase of the shaft or the oval axis is sequentially or randomly changed in the circumferential direction, furthermore, in the bellows shape, between adjacent peaks. Wherein the amount of change in the phase of the elliptical axis or the elliptical axis is 3 degrees or more.

[0006]

Accordingly, the present invention relates to a resin hose having a bellows structure at least partially,
The cross section of the bellows is elliptical or elliptical (hereinafter referred to as
Simply referred to as an ellipse). Furthermore, the height of the bellows is changed sequentially or randomly in the circumferential direction. In the case where the cross section of the bellows section is a perfect circle, it is possible to obtain good flexibility,
The hose expands greatly when pressurized, and the deformation of the hose after piping becomes a problem. It has been found that both the flexibility and the pressure resistance can be provided by making the peak cross-sectional shape of the bellows portion elliptical, and forming a flexible portion and a relatively rigid portion in the circumferential direction.

By making the cross section of the peak portion of the bellows elliptical, the pressure resistance of the hose is greatly improved.
When the elliptical axes of the ellipses are in the same direction, the flexibility (easiness of bending) of the hose has directionality. In order to solve this problem, it is effective to sequentially or randomly change the elliptical axis of the cross section of the adjacent mountain in the circumferential direction, and thereby it is possible to prevent the flexibility of the hose from becoming directional. . The amount of change in the direction of the ellipse axis between adjacent peaks is preferably 3 degrees or more, particularly preferably 15 degrees or more. If the change amount is less than 3 degrees, the number of pitches until the directionality is completely lost needs to be 30 or more, and the hose is likely to be twisted at the time of pressurization, which is not preferable. Further, it is preferable that the change amount is 90 degrees or less at most.

Since the flexibility and the resistance to pressure deformation change depending on the ratio of the peak height of the bellows cross section, the peak height ratio is important in the design of the hose. As the peak height ratio of the bellows section decreases, the hose elongation during pressurization decreases, which is effective in improving the pressure deformation resistance. A preferable peak height ratio is 0.75 or less, more preferably 0.5. It is as follows. However, if it is too small, flexibility tends to be lost,
It is preferably at least 0.1 or more.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a side view schematically showing an embodiment of a bellows structure of a resin hose according to the present invention, and a cross-sectional view taken along a line AA. FIG. 2 is a side view and an AA cross-sectional view schematically showing one embodiment of the bellows structure of the multilayer hose of the present invention according to claim 3.

In these figures, 1 is a resin bellows hose, h1 is the height of the bellows cross section in the minor axis direction, h
2 is the peak height of the bellows section in the major axis direction, and Θ is the displacement amount of the elliptical axis of the adjacent bellows section. The inner surface of the hose and the valley of the bellows are almost perfectly circular, and the peak of the bellows is elliptical.

The method for producing the flexible hose of the present invention includes:
Known extrusion or blow molding methods are used, for example,
After supplying and melting and kneading the thermoplastic resin composition to the extruder,
After a pressure is supplied into the die to form an annular flow, it is extruded out of the die, shaped into a predetermined shape by a generally known corrugator, and cooled to obtain a bellows hose.

It is also possible to obtain a flexible multilayer hose having two or more layers using a plurality of extruders. The above-described method of manufacturing a hose is merely an example, and the present invention is not limited to this.

[0013] The flexible hose of the present invention thus obtained is excellent in flexibility and pressure-resistant deformation, and has a radiator hose,
It is effective as automotive parts such as heater hose, reservoir tank hose, fuel tube, fuel filler hose, and fuel vapor hose, road heating pipe, and floor heating pipe.

[0014]

The present invention will be described in detail below with reference to examples.

The flexibility and pressure resistance of the flexible hose described in the following examples and comparative examples were measured by the following methods.

According to the corrugating method described above, the mixture is melt-kneaded in an extruder, supplied to an extrusion die, and extruded as a tubular body from a die face at the tip thereof. This is shaped by a corrugator, solidified by cooling, and has an outer diameter of φ30 mm and an inner diameter of φ2.
A 7 mm bellows tube was molded. The bellows tube was evaluated according to the following method.

1. Flexibility The bellows tube was cut into 700 mm, one end was restrained, and a load of 100 g was applied to the other end, and the amount of deflection was measured.

2. Pressure Resistance Deformability The bellows tube was cut into 700 mm, one end was sealed with a metal fitting, and the axial elongation of the tube when an internal pressure of 4 kg / cm ² was applied at 23 ° C. was measured.

Comparative Example 1 Plasticized nylon 11 resin (manufactured by Toray Industries, Inc .: "Rilsan" BESN BK P20T)
L) was fed to a 40 mmφ extruder, and the cylinder temperature was set to 23.
Melt and kneaded at 0 ° C., using a commercially available corrugating apparatus, the outer diameter φ30 mm, the inner diameter φ27 mm, the wall thickness 1.5 mm, the bellows height 4 mm, and the pitch 6 mm in the usual manner.
A hose having a round shape of the bellows was obtained. Table 1 shows the flexibility and pressure resistance of this hose.

[Examples 1 to 3] The hoses of Examples 1 to 3 were the same as the comparative example except that the bellows section had an elliptical cross-sectional shape and the peak height ratio of the bellows was the ratio shown in Table 1. .

As shown in Table 1, the hose having an oval cross-section of the bellows portion according to the present invention has remarkably improved pressure-resistant deformability. In particular, when the peak height ratio is 0.5 or less, the pressure resistance deformability is less than 30% as compared with a circular cross-section.
Undesirable elongation of the bellows hose is substantially prevented.

The flexibility shows almost the same flexibility in the major axis direction of the bellows section as that of a circular hose, but tends to be slightly hard in the uniaxial direction.

[0023]

[Table 1]

[Embodiments 4 to 7] The elliptical axis is moved in one direction in the circumferential direction so that the displacement amount (as shown in Table 2) of the elliptical axis of the cross section of the adjacent bellows becomes the value shown in Table 2. A flexible hose was manufactured in the same manner as in Example 2, except that the hose was displaced in a bellows shape.

When the cross-section axes of the bellows portions are all arranged in the same direction as in the first to third embodiments, the flexibility tends to have directivity. However, as shown in Table 2, the cross-section axes of the adjacent bellows are sequentially changed. By displacing in the circumferential direction, the directionality of the flexibility can be improved. However, in Example 4, the amount of displacement was slightly small at 5 degrees, so that the hose was slightly twisted at the time of pressurization due to unevenness in the rigidity of the hose. No occurrence was observed, and the directionality of the flexibility was hardly observed.

[0026]

[Table 2]

[0027]

The flexible hose having an elliptical cross section of the bellows portion of the bellows portion according to the present invention has both excellent flexibility and pressure-resistant deformability, and is a cooling hose for automobiles used in a pressurized system under high temperature conditions. It can be used to advantage in media circulation pipe applications such as fuel-based hoses, heating systems for snow melting or heating.

[Brief description of the drawings]

FIG. 1 is a side view and a cross-sectional view schematically showing one embodiment of the bellows structure of the resin hose according to the first aspect of the present invention.

FIG. 2 is a side view and a cross-sectional view schematically showing one embodiment of the bellows structure of the resin hose according to the third aspect of the present invention.

[Explanation of symbols]

1: Resin bellows hose, h1: Mountain height in the minor axis direction of bellows section, h2: Mountain height in the major axis direction of bellows section, Θ: Displacement of elliptical axis of adjacent bellows mountain section

Claims (4)

[Claims] 1. A resin hose excellent in pressure-resistant deformation, characterized in that at least a part of the hose has a bellows shape, and a cross section of a peak portion of the bellows shape is an ellipse or an ellipse. 2. An elliptical or elliptical shape having a bellows-shaped peak cross section is a peak height ratio (h1 / h2) between a peak height (h1) in a short axis direction and a peak height (h2) in a long axis direction. Is 0.75
The resin hose excellent in pressure-resistant deformation resistance according to claim 1, characterized in that: 3. An elliptical or elliptical shape having a bellows-shaped peak cross-section, and the phase of the elliptical axis or the elliptical axis changes between adjacent peaks sequentially or randomly in the circumferential direction. The resin hose excellent in pressure-resistant deformation resistance according to claim 1 or 2, characterized in that: 4. The pressure-resistant deformability according to claim 3, wherein the amount of change in the phase of the elliptical axis or the elliptical axis between adjacent peaks in the bellows shape is 3 degrees or more. Resin hose.