JPH1078172A - Air hose - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air hose having an ozone resisting function in addition to elasticity or restorability. SOLUTION: An air hose 10 is formed to have the first rubber layer 12 occupying the main part thereof, and the second rubber layer 14 formed on the external surface of the first rubber layer 12. Furthermore, the first rubber layer 12 is a rubber layer made of acrylonitrile-butadiene copolymer (NBR), and the second rubber layer 14 is a rubber layer made of chlorosulfonated polyethylene(CSM). In this case, the first rubber layer 12 and the second rubber layer 14 are concurrently molded, using a hose extruder and the thickness of the second rubber layer 14 has a value between 0.2mm and about 0.6mm. Also, the air hose 10 displays a ozone resisting function via the second rubber layer 14, regardless of thickness as small as 0.3mm, and elasticity or restorability as a hose can also be provided, due to the first rubber layer 12 formed to have approximately the same thickness as an NBR monolayer hose, as a result of applying small thickness to the second rubber layer 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air hose connected to an air device.

[0002]

2. Description of the Related Art An air hose of this type is required to have various characteristics such as flexibility and productivity. For example, in vehicles equipped with various pneumatic devices, the pneumatic devices are located not only in the engine room where various devices such as the engine are effectively arranged without gaps, but also in the vicinity of the underbody around the fuel tank. Due to its existence, it requires connection to these pneumatic devices in a bent path. Further, if the pipe is bent, even if it is deformed and deformed to some extent at the time of bending, it is not preferable because the remaining strain causes resistance of air passing through the pipe. For this reason, the air hose used for the vehicle is required to have elasticity and resilience. Then, a single-layer air hose using a rubber material having excellent elasticity and resilience, for example, butadiene-acrylonitrile copolymer (NBR) is used. In addition, examples of the air hose used in the vehicle include an air hose connected to air devices such as a vacuum control valve, a vacuum switch, a diaphragm valve, and a check valve in an engine supply / exhaust system, a fuel vapor system, and the like. .

[0003]

SUMMARY OF THE INVENTION However, NBR
Conventional single-layer air hoses have excellent elasticity and resilience, but when used in vehicles used in various outdoor environments, cracks may occur on the outer surface due to ozone deterioration. On the other hand, a rubber material having excellent ozone resistance, for example, an air hose using only a chlorosulfonated polyethylene (CSM) instead of NBR is not preferable because permanent deformation due to compression is apt to remain and elasticity and restoring property are impaired. .

[0004] The present invention has been made to solve the above problems, and has as its object to provide an air hose having ozone resistance in addition to elasticity and resilience.

[0005]

Means for Solving the Problems and Their Functions and Effects In order to solve the above problems, an air hose of the present invention is an air hose connected to an air device, comprising a first rubber made of a butadiene rubber material. The layer forms an air conduit, and a second rubber layer made of a chlorosulfonated polyethylene rubber material is applied to the outer periphery of the first rubber layer by about 0.2 mm.
It is characterized by being formed with a thickness of about 0.6 mm.

In the air hose of the present invention having the above structure, when the outer diameter of the hose is approximately the same as the conventional one, the second rubber layer on the outer periphery of the first rubber layer is about 0.2 to about 0.6 mm. By ensuring the thickness of the first rubber layer, the thickness of the first rubber layer is secured to a level close to that of the conventional single layer, and the properties of the butadiene-based rubber material, that is, elasticity and resilience, Demonstrate. On the other hand, the second rubber layer exposed to the outside air
Since the chlorosulfonated polyethylene rubber material has excellent ozone resistance, even a layer having a thickness as thin as about 0.2 to about 0.6 mm can exhibit resistance to ozone deterioration. Therefore, according to the present invention, an air hose having ozone resistance in addition to elasticity and restoring property can be provided.

[0007] In this case, the second rubber layer is used as a rubber layer (second rubber) when coextruded with a hose extrusion molding machine.
From the viewpoint of uniform formation of the rubber layer),
mm or more is preferable. In addition, the outer diameter of the hose is set to the same level as the conventional one, and the thickness of the first rubber layer is secured to a level approximating that of the conventional single layer, and the original function of the air hose (tightening of the pipeline) and elasticity From the viewpoint of not significantly impairing the resilience and the resilience, the second rubber layer has a thickness of about 0.2.
It is preferable to set it to 6 mm or less.

[0008]

Next, an embodiment of an air hose according to the present invention will be described with reference to examples. FIG. 1 shows the first
It is an expanded sectional view of air hose 10 of an example. As shown in FIG. 1, the air hose 10 has a first rubber layer 12 occupying a main part thereof, and a second rubber layer 14 formed on the outer periphery thereof. The first rubber layer 12 is a rubber layer made of a butadiene-acrylonitrile copolymer (NBR), and the second rubber layer 14 is a rubber layer made of chlorosulfonated polyethylene (CSM). in this case,
The air hose 10 has the same inner and outer diameters as a single-layer air hose conventionally used in vehicles, and has an inner diameter,
That is, the inner diameter of the first rubber layer 12 is about 7 mm. The outer diameter of the second rubber layer 14 is about 12 m.
m, and the thickness is about 2.5 mm. Then, the second rubber layer 14 is formed simultaneously with the first rubber layer 12 using a hose extruder, and has a thickness of about 0.3 mm.
Thus, it is extruded coaxially with the first rubber layer 12 by an extruder.

Here, an evaluation test of the air hose 10 of the embodiment will be described. The hose to be compared (comparative hose) is a single-layer NBR air hose having the above inner and outer diameters. First, the air hose 10 of the example and the hose of the comparative example were prepared, and an ozone resistance test was performed in the following procedure. First, as shown in FIG. 2, each air hose having an appropriate length is bent at approximately 180 degrees at substantially the center thereof, and an appropriate portion thereof is tied up with a wire. Next, the specimen is kept in this state at room temperature for 16 to 24 hours.
Let stand for a long time, then test environment of high temperature and high ozone concentration (temperature: 40 ± 2 ° C, ozone concentration: 50 ± 5 pphm)
Put on. Then, the elapsed time from the placing in the test environment until the occurrence of cracks on the surface of the test object was confirmed with a loupe or the like was measured. In the test sample of the air hose 10 of the example, no crack was generated even after 70 hours, but in the test sample of the comparative hose, the generation of a crack was confirmed after 10 hours. . For this reason, it turned out that the air hose 10 of an Example has ozone resistance.

In this case, the air hose 10 has a rubber layer (first rubber layer 12) of NBR exhibiting elasticity and resilience having a thickness of about 1.7 mm, and a conventional single-layer air hose having a thickness of about 2 mm. Of about 85%. Therefore, according to the air hose 10, functions similar to those of the conventional air hose could be exhibited as described below.

First, the hermetic function of the air hose, which is an essential function of the air hose, will be described. The air hose 10 (inner diameter 7 mm, outer diameter 12 mm) of the above embodiment is expanded and connected to a pipe (outer diameter 8 mm) corresponding to a connection port of an air device to which the air hose 10 is connected, and remains connected to the pipe. It is left in a heating environment at 120 ° C. for 24 hours in this state. And
After that, the sealing property (airtightness) of the connection part was examined. That is, the sealing performance when the hose was forcibly heat-aged was examined. In this case, the second rubber layer 14
Has a thickness of about 0.2 mm, 0.3 mm, 0.4 mm, 0.
The sealing properties of the 6 mm air hose 10 of the example and the 0.8 mm air hose (comparative air hose) in which the thickness of the second rubber layer 14 exceeds the range of the present invention were examined. In measuring the sealability, the free end of each air hose left in the above-mentioned heating environment is closed by an appropriate method, water is pumped into the hose from the pipe side, and water leaks from the connection point with the pipe. The pressure at the time of discharge (pressure of feeding) was measured. The result is shown in FIG.

As is apparent from FIG. 3, if the thickness of the second rubber layer 14 is in the range of 0.2 mm to 0.6 mm, even if the hose undergoes thermal aging, the sealing property is not improved. It is about 20 to about 24.5 N / cm ² , which is a value exceeding the lower limit seal value. However, if the thickness of the second rubber layer 14 exceeds this range, the thickness of the second rubber layer 14 falls below the lower limit seal value and the function of the hose is impaired. That is, since the thickness of the second rubber layer 14 is within the above range, the thickness of the first rubber layer 12 is set to NBR.
It is almost the same as a single-layer hose.
To 90%, and the same level of sealing performance as that of a conventional air hose can be secured. On the other hand, if the thickness of the second rubber layer 14 exceeds this range (0.8 mm), the thickness of the first rubber layer 12 becomes 60% of that of a single layer, and the first rubber layer 12 becomes thin. Because it is too much, the sealing property is impaired. In addition, the lower limit seal value was defined as a minimum required value when used by connecting to an air device of a vehicle.

The sealing property is obtained when the air hose is expanded and connected to the pipe, and is obtained based on the elasticity and the resilience exhibited by the hose. For this reason, the air hose 10 of the embodiment has the ozone resistance as described above, and can surely exhibit the elasticity and the resilience within a range that can be practically used.

The elasticity and the restoring property of the hose are as follows. If the air hose is a single-layer NBR, the temperature and the temperature will be 120 ° C X
Compression set of about 13 when compressed for 22 hours
About 20%. On the other hand, in the case of the air hose 10 in which the thickness of the first rubber layer 12 is in the above range, the compression set under the same conditions is about 20 to 27%. At the level, it was possible to secure the elasticity and resilience of the hose to a similar degree. That is, the air hose 10 of the embodiment has the ozone resistance as described above, and can also exhibit elasticity and resilience.

The embodiments of the present invention have been described above.
The present invention is not limited to the above-described examples and embodiments at all, and it goes without saying that the present invention can be implemented in various modes without departing from the gist of the present invention.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view of an air hose 10 according to an embodiment.

FIG. 2 is an explanatory diagram for explaining the contents of an evaluation test performed on the air hose 10.

FIG. 3 is a graph showing the results of an evaluation test performed on the air hose 10.

[Explanation of symbols]

 10 air hose 12 first rubber layer 14 second rubber layer

Claims (1)

[Claims] 1. An air hose connected to an air device, wherein a first rubber layer made of a butadiene rubber material forms an air conduit, and a second rubber made of a chlorosulfonated polyethylene rubber material A layer of about 0.2 to about 0.
An air hose formed with a thickness of 6 mm.