JP2543391B2 - Hose - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a hose such as a hose for transporting a refrigerant, and particularly to a hose used as a pipe for a car cooler of an automobile or an air conditioner.

[Conventional technology]

As a hose for transporting a refrigerant such as Freon gas, for example, the hose shown in FIG. 3 is known. This hose
The inner tube layer 1 is divided into three layers, and the inner rubber layer 10 is the innermost layer,
The intermediate resin layer 11 on the outer side and the outer rubber layer on the outer side
It has a three-layer structure of 12. A fiber reinforcement layer 13 and an outer tube rubber layer 14 are formed in this order on the outer circumference of the inner tube layer 1. Of these, the inner rubber layer 10 in the inner tube layer 1 is
As a protective layer for preventing deterioration of the inner pipe layer 1 due to metal ions or metal salts generated from the metal pipe communicating with the inner pipe layer 1,
Alternatively, it is provided to improve the reliability of the caulking seal with respect to the mouthpiece inserted into the inner tubular layer 1. The intermediate resin layer 11 is provided to maintain gas impermeability of the inner tube layer 1 to a low molecular weight gas such as Freon gas, and the outer rubber layer 12 is provided to improve flexibility of the entire inner tube layer 1. ing. However, in the three-layer structure of the inner tube layer 1,
Since the inner rubber layer 10 having poor gas impermeability is formed on the innermost layer and the intermediate resin layer 11 having excellent gas impermeability is formed on the outer periphery thereof, the refrigerant gas flowing through the inner tube layer 1 is It penetrates the inner rubber layer 10 and reaches the intermediate resin layer 11, where it is blocked. Therefore, unless the inner rubber layer 10 and the intermediate resin layer 11 are firmly bonded, the refrigerant gas stays at the interface between the layers 10 and 11. From this point of view, an adhesive composed of a phenol resin or a mixture of a phenol resin and an epoxy resin is used for bonding the intermediate resin 11 and the inner rubber layer 10. However, while this adhesive is highly adhesive,
In the cured state, the hardness is high, so the impact resistance is weak, and since the adhesive layer itself is a thin film, cracking of the adhesive layer easily occurs when bending stress is applied. When the adhesive layer is destroyed in this manner, the intermediate resin layer 11 that is in close contact with the adhesive layer
However, in some cases, up to the outer rubber layer 12 will follow and be destroyed. As described above, when the hose is used in a state where bending stress is applied, there is a big drawback that the intermediate resin layer 11 and the outer rubber layer 12 are destroyed due to the destruction of the adhesive layer, which may lead to gas leakage. are doing. Further, if the intermediate resin layer (having a hardness higher than that of rubber) 11 is made thin for the purpose of improving the flexibility of the hose, the strength becomes small and the destruction of the intermediate resin layer is promoted. Also,
When the hose for transporting the refrigerant is bent with a small radius of curvature, it is kinked (buckled) and cannot be restored.

[Problems to be solved by the invention]

As described above, the conventional refrigerant transport hose has good anti-refrigerant gas characteristics in terms of the structure, but lacks flexibility, and therefore, in actual use, it breaks the adhesive layer and also destroys the intermediate resin layer. There is a big problem that it causes a gas leak and causes a kink when bending and piping.

The present invention has been made in view of such circumstances,
It is an object of the present invention to provide a hose which is excellent in flexibility and bending kink property (anti-buckling property) and also excellent in refrigerant gas characteristics.

[Means for solving problems]

In order to achieve the above object, the hose of the present invention is an inner tube layer, a fiber reinforcing layer formed on the outer periphery of the inner tube layer,
A hose comprising an outer tube layer formed on the outer periphery of the fiber reinforced layer, wherein the inner tube layer is formed of an inner rubber layer, an outer rubber layer, and an intermediate resin layer sandwiched between the inner rubber layer and the outer rubber layer. The rubber layer has a structure in which spiral outer surface extending in the axial direction is formed on the entire outer surface of the rubber layer.

[Action]

That is, according to the present invention, spiral concave and convex portions extending in the axial direction are formed on the entire outer peripheral surface of the inner rubber layer, and the intermediate resin layer is formed thereon with the adhesive layer interposed therebetween. Therefore,
Due to the shape of the inner rubber layer itself, the overall flexibility is improved, and the flexibility is maintained even when a conventional hard adhesive is used. Further, in the case where bending stress acts on the adhesive resin layer when the hose is twisted and bent, if the outer periphery of the adhesive resin layer is flat, the above-mentioned stress acts along the circumference of the outer periphery, but the outer circumference is circular. Corrugated in the circumferential direction (due to spiral irregularities)
Then, the stress is dispersed in the circumferential direction and the radial direction on the surface of the corrugated wave. Therefore, the adhesive resin layer does not break during torsional bending, and the inner and outer rubber layers do not break along with it. In addition, since the thickness of the intermediate resin layer can be reduced, the bending kink resistance can be greatly improved, and the intermediate resin layer can be bent with a small radius of curvature.

 Next, the present invention will be described in detail.

A hose such as a hose for transporting a refrigerant of the present invention has a structure as shown in FIG. In the figure, 10 is an inner rubber layer,
11 is an intermediate resin layer, 12 is an outer rubber layer, 13 is a fiber reinforced layer, 14
Is the outer tube layer. Then, the inner rubber layer 10 and the intermediate resin layer 1
1, the outer rubber layer 12 becomes the inner tube layer 1. The inner rubber layer 10 has rubber elasticity and has a hose sealability,
As described above, it has a role of protecting the intermediate resin layer, which is the outer layer thereof, from metal deterioration. The intermediate resin layer 11 has considerably higher rigidity than a rubber material and has a role of blocking the permeation of a low molecular weight gas. Then, the outer rubber layer 12 having rubber elasticity is
When the fiber reinforcing layer 13 is formed directly on the surface of the intermediate resin layer 11, it becomes lacking in elasticity, and is formed in view of the fact that when the refrigerant transport hose is bent, the inner surface of the hose does not kink and is not restored. And has a role of elastically supporting the intermediate resin layer 11.

The inner rubber layer 10 of the inner tube layer 1 is usually formed of a rubber material such as acrylonitrile-butadiene copolymer (NBR), chlorosulfonated polyethylene (CSM), chlorinated polyethylene (CPE), Spiral unevenness extending in the axial direction is formed on the entire outer peripheral surface. This is the greatest feature of this invention. Due to this spiral uneven shape,
In the cross-sectional shape of the hose, as shown in FIG. 1, the inner rubber layer 10 is in a state as if a corrugation was formed in the circumferential direction. The height of the wave (height of the unevenness) is 0.2 to the pitch a of the wave (see FIG. 1).
It is preferably set to 1.5 times, particularly preferably 0.7
~ 1.2 times. That is, if it is less than 0.2 times, there is not much difference in terms of curing from a smooth state with no unevenness, and if it exceeds 1.5 times, there is too much difference in unevenness and the intermediate resin layer 11 is formed on the inner rubber layer 10.
This is because when the above is formed, the intermediate resin layer 11 does not completely adhere to the inner rubber layer 10, and air (air) accumulates in the valley portion, which tends to cause a problem in the reliability of the product. Also,
The pitch b of the wave in the axial direction of the unevenness (see FIG. 2) is preferably set to about 0.6 to 5 times the height of the wave in terms of the wavy effect. 2-3 times is most effective.

Intermediate resin layer 11 formed on the outer periphery of the inner rubber layer 10
From the viewpoint of gas impermeability, it is preferable to use polyamide resin such as nylon 6 or nylon 66.

The outer rubber layer 12 formed on the outer periphery of the intermediate resin layer,
Although it depends on the function to be exerted, it is preferable to form it using NBR, CSM, CPE, etc. in consideration of gas permeability.
Considering the water permeability, it is preferable to use ethylene-propylene-diene rubber (EPDM), chlorinated butyl rubber (Cl-IIR), butyl rubber (IIR), CSM or the like.

The fiber reinforcing layer 13 may be one that is used for ordinary hoses, and is formed by braiding or spiral knitting of threads mainly composed of synthetic fibers such as polyester fibers, nylon fibers, vinylon fibers, and aramid fibers. To be done.

The outer tube layer 14 is a layer exposed to the outside, and is made of EPDM, Cl
-IIR, chloroprene rubber (CR), epichlorohydrin rubber (CHC), etc. are used according to the purpose of use.

The hose for transporting the refrigerant having the above structure has an inner rubber layer.
10 and the intermediate resin layer 11, and the intermediate resin layer 11 and the outer rubber layer 12
Are firmly adhered at each interface by an adhesive. As the adhesive, an adhesive containing a resin component composed of at least one of a phenol resin and an epoxy resin as a main component is usually used.

The hose such as the hose for transporting a refrigerant of the present invention can be manufactured by laminating and forming the above layers in the following manner, for example.

(1) An unvulcanized rubber composition for forming the inner rubber layer 10 is extruded onto a mandrel from an extruder. At this time, a jig (a general jig, for example, a thread rolling tap) for forming wavy unevenness is provided near the head of the extruder, and a spiral unevenness is formed on the outer peripheral surface of the rubber while rotating the jig. Then, a tubular body with spiral irregularities is obtained.

(2) Next, after applying an adhesive to the outer peripheral surface of the pipe, while applying a vacuum to the outer periphery of the pipe, a resin for forming the intermediate resin layer 11 is extruded and coated thereon by a resin extruder.

(3) After applying an adhesive to the outer peripheral surface of the intermediate resin layer 11, the rubber composition for forming the outer rubber layer 12 is extruded on the adhesive to obtain a three-layer structure pipe (inner pipe).

(4) The outer rubber layer (12) of the inner tube is coated with rubber glue on the unvulcanized outer peripheral surface, and then the fiber for the fiber reinforcing layer 13 is braided thereon to form the reinforcing fiber layer 13.

(5) After applying rubber glue to the outer peripheral surface of the fiber reinforcing layer 13, the rubber composition for forming the outer tube layer 14 is extruded thereon.

(6) The laminated tube is vulcanized and bonded by lead vulcanization to be integrated, and then water pressure is applied to remove the mandrel. The vulcanization conditions are set to a temperature of 150 ° C. and a time of 60 minutes.

In the above manufacturing method, the thickness of the inner rubber layer 10 is generally 0.2.
Set to ~ 2.0 mm. That is, if the thickness is less than 0.2 mm, it will be difficult to manufacture a hose for transporting a refrigerant, and if the base is crimped, it will be damaged, and if it exceeds 2.0 mm, the flexibility will be poor.

The thickness of the intermediate resin layer 11 is 0.05 to 0.5 mm, especially 0.2.
It is preferable to set it to about mm. That is, 0.05 mm
If it is less than 0.5 mm, the gas easily permeates, and if it exceeds 0.5 mm, the rigidity is increased and the hose itself loses flexibility.

Moreover, the thickness of the outer rubber layer 12 is preferably set to 0.5 to 1.5 mm. If the thickness is less than 0.5 mm, it is not possible to cover the axial spiral irregularities formed inside, and the mandrel expands due to heating during hose vulcanization, and the irregularities become smaller, or conversely 1.5 mm. If it exceeds, the rigidity becomes large and the flexibility of the hose itself deteriorates.

Further, the thickness of the outer tube layer 14 is usually preferably 0.5 to 2.0 mm. That is, it is preferable to increase the wall thickness in order to improve the water permeation resistance, but if the wall thickness is excessively thick, the usability deteriorates. Therefore, it is preferable that the outer tube layer 14 has a thickness within the above range.

The hose for transporting the refrigerant thus obtained has a spiral unevenness extending in the axial direction on the entire outer peripheral surface of the inner rubber layer, and therefore has a high flexibility, and the resin layer and The outer rubber layer is not destroyed and has excellent resistance to refrigerant gas.

〔The invention's effect〕

As described above, the hose of the present invention is formed with spiral irregularities extending in the axial direction on the entire outer peripheral surface of the inner rubber layer, so that the hose is highly flexible, and when a twist bending ratio is applied. The cracks and fractures of the adhesive layer, the resin layer and the inner and outer rubber layers in the inner pipe layer are prevented. In addition, it has good bending kinking property and does not kink even when bent with a small radius of curvature. Therefore, it is most suitable for refrigerant transportation.

 Next, examples will be described together with comparative examples.

[Examples 1 to 5 and Comparative Example] Using the materials shown in Table 1 below, the hoses of the Example product and the Comparative example product (hose inner diameter: 11.5 m) were manufactured according to the above-described manufacturing method.
m) was prepared.

For each hose thus obtained, flexibility,
The bending kink property and the repeated pressure test were evaluated. The results are shown in Table 2 below.

 Each evaluation was performed in the following procedure.

<Flexibility> The hose was bent to an R (angle) of 100, and the force required to maintain that state was measured with a tension bakari.

<Bending kink property> The hose was bent and the bending R at which crushing occurred was measured.

<Repeated Pressurization Test> The hose was connected to a test device that allows oil (usually Suniso 5GS) to circulate and pressurize, and was held under the following conditions to measure the number of times the hose was damaged or leaked.

Pressure cycle: 35cpm Oil temperature: 100 ℃ Ambient temperature: 100 ℃ From the above results, it is understood that all of the example products are excellent in flexibility and the bending kink property is smaller than that of the comparative example product. Also, the durability of the entire hose is excellent.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view of the present invention, FIG. 2 is an explanatory diagram showing its configuration, and FIG. 3 is a longitudinal sectional view showing a conventional product. 1 ... Inner tube layer, 10 ... Inner rubber layer, 11 ... Intermediate resin layer,
12 …… Outer rubber layer, 13 …… Fiber reinforced layer, 14 …… Outer tube layer

Claims (1)

(57) [Claims] 1. An inner tube layer, a fiber reinforcement layer formed on the outer periphery of the inner tube layer, and an outer tube layer formed on the outer periphery of the fiber reinforcement layer, wherein the inner tube layer is an inner rubber layer. A hose formed of an outer rubber layer and an intermediate resin layer sandwiched between the outer rubber layer and the inner rubber layer, wherein spiral ridges extending in the axial direction are formed on the entire outer surface of the inner rubber layer. A hose to do.