JPH06201074A - Reinforced hose - Google Patents

Abstract

PURPOSE:To heighten fatigue resistance and reduce the quality of cubic expansion in a reinforced hose with a reinforcing yarn layer provided between an inner tube rubber layer and a cover rubber layer by using polyester yarn with specific characteristic value as the yarn forming the lower yarn layer of the reinforcing yarn layer, and using vinylon yarn as the yarn forming an upper yarn layer. CONSTITUTION:A reinforced hose used as an automobile high pressure hose or the like is formed of an innermost tube rubber layer 1, a lower yarn layer 2 braided on the surface of the layer 1, an intermediate rubber layer 3 covering the surface of the lower yarn layer 2, an upper yarn layer 4 braided on the surface of the layer 3, and a cover rubber layer 5 covering the surface of the upper yarn layer 4; and a mouthpiece 6 is fastened to the end part by calking. In this case, polyester yarn is used as the yarn forming the lower yarn layer 2, and this polyester yarn is to have such characteristic value that tensile strength per unit denier is 8g or more, elongation is 10+ or -1.5%, and elongation at the load time of 3g per unit denier is 2.7+ or -1.0%. Vinylon yarn is used as the yarn forming the upper yarn layer 4. Both characteristics of satisfactory fatigue resistance and cubic expansion quantity are thereby obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reinforcing hose which is used for a flow path of a pressure fluid such as a hydraulic hose and has a reinforcing yarn layer braided in the middle of a rubber layer.

[0002]

2. Description of the Related Art A hose used for a flow path of a pressure fluid such as a hydraulic hose is required to have a strength capable of withstanding a high pressure.
Therefore, a hose base such as rubber or resin is often insufficient in strength, and a hose having a reinforcing thread layer in which reinforcing threads are braided in the middle is generally used. Also, a single layer of reinforcing yarn may be insufficient, and in such a case, a reinforcing hose having a plurality of reinforcing yarn layers is used.

Here, as the material of the yarn constituting the reinforcing yarn layer, vinylon, polyester, rayon, aramid fiber or the like is used, and it is used while making the best use of respective characteristics depending on the application.

[0004]

It has been known that the reinforcing hoses using the reinforcing threads made of various materials described above have different characteristics. The differences in the characteristics are summarized in Table 1 regarding fatigue resistance and volume expansion. Fatigue resistance indicates durability when repeatedly bending while applying high pressure at high temperature, volume expansion indicates internal volume change when high-pressure fluid is supplied, and volume expansion is generally It is desirable to be small.

[0005]

[Table 1] As shown in Table 1, there is no reinforcing yarn satisfying both properties of fatigue resistance and volume expansion so far, and both properties are considered to be antinomy events. Therefore, in a hose having a plurality of reinforcing thread layers, the properties of the lower thread layer and the upper thread layer are changed to balance the two characteristics, but this has not been sufficient.

The present invention has been made in view of such circumstances, and an object thereof is to satisfy both characteristics of fatigue resistance and volume expansion amount.

[0007]

Means for Solving the Problems The inventors of the present invention have made earnest studies on the relationship between various physical properties of the reinforcing yarn and the fatigue resistance and the volume expansion amount. It has been found to satisfy the characteristics. When the polyester reinforcing yarn is used for the lower yarn layer, the characteristics are improved,
At this time, they discovered that the use of vinylon yarn for the upper yarn layer improved the characteristics most, and completed the present invention.

That is, the reinforcing hose of the present invention is provided with an inner tube rubber layer and a cover rubber layer, and a reinforcing hose having at least two reinforcing thread layers consisting of an upper thread layer and a lower thread layer in an intermediate layer between the respective rubber layers. In the hose, the yarn constituting the lower yarn layer has a tensile strength per unit denier of 8 g or more and an elongation of 10 or less.
A polyester yarn having a characteristic value of ± 1.5% and an elongation at a load of 3 g per unit denier of 2.7 ± 1.0%, and the yarn forming the upper yarn layer is a vinylon yarn. To do.

When the tensile strength per unit denier of the polyester yarn constituting the lower yarn layer is less than 8 g, sufficient rupture strength cannot be obtained in the reinforcing hose, and when the elongation is less than 8.5%. Fatigue resistance cannot be obtained. If the elongation at a load of 3 g per unit denier is greater than 3.7%, the volume expansion amount becomes large, which is not preferable. Furthermore, elongation is 1
If it exceeds 1.5% or the elongation at a load of 3 g per unit denier is less than 1.7%, other characteristic values of the reinforcing yarn will deviate from the above range, and similar problems will occur in the reinforcing hose. .

The vinylon yarn constituting the upper yarn layer may be the same as the conventional one. By forming the upper yarn layer made of vinylon yarn on the lower yarn layer made of the polyester yarn, the balance between fatigue resistance and volume expansion is optimized.

[0011]

In the reinforcing hose of the present invention, the yarn constituting the lower thread layer has a tensile strength of 8 g or more per unit denier, an elongation of 10 ± 1.5%, and an elongation at a load of 3 g per unit denier. A polyester yarn having a characteristic value of 2.7 ± 1.0%. By having such a lower thread layer, the fatigue resistance is remarkably improved and the volume expansion amount is also reduced.

In the reinforcing hose of the present invention, the upper thread layer is formed of vinylon thread. Vinylon yarn has the characteristic that the volume expansion amount is extremely small. That is,
In the reinforced hose of the present invention, fatigue resistance is mainly secured in the lower yarn layer, the volume expansion amount is suppressed to be smaller than that of the conventional polyester yarn, and the volume expansion amount is suppressed to be smaller in the upper yarn layer. This makes it possible to achieve both fatigue resistance and volume expansion performance.

[0013]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples. (Embodiment) FIG. 1 shows a reinforcing hose according to an embodiment of the present invention together with a mouthpiece. This reinforcing hose is a high-pressure hose for automobiles, and includes the innermost tube rubber layer 1 and the tube rubber layer 1
The lower yarn layer 2 braided on the surface, the intermediate rubber layer 3 coated on the lower yarn layer 2 surface, the upper yarn layer 4 braided on the intermediate rubber layer 3 surface, and the upper yarn layer 4 surface coated The cover rubber layer 5 is formed, and the base 6 is fastened to the end portion by caulking.

The tube rubber layer 1 is made of EPDM. The lower yarn layer 2 is formed by braiding 1500 denier polyester yarn under the condition of two-ply yarn-20 strokes. This polyester yarn has a tensile strength of 9.0 g,
The elongation has a characteristic value of 10.0% and the elongation at a load of 3 g per unit denier of 2.7%. The material of the polyester yarn will be referred to as reinforced PE hereinafter.

The intermediate rubber layer 3 is made of NR. The upper yarn layer 4 is made of 1200 denier vinylon yarn.
The main composite yarn is formed by braiding under the condition of 24 shots. This vinylon yarn has a tensile strength of 8.3 g and an elongation of 7.0.
%, The elongation at a load of 3 g per unit denier has a characteristic value of 2.5%.

The cover rubber layer 5 is made of EPDM. The volume expansion and fatigue resistance of the reinforcing hose of this example configured as described above were measured, and the results are shown in Table 2. The volume expansion amount is 305 m when pressurized at 105 kgf / cm ² based on JIS2601.
The amount of change in the internal volume of the hose having a free length of m was measured. For the fatigue resistance, a test of repeatedly bending while pressurizing at a pressure of 100 kgf / cm ² at 100 ° C. was repeated, and the number of times of repeated bending when the hose ruptured was measured. (Comparative Example 1) A vinylon yarn of 1200 denier has the same configuration as that of the example except that the lower yarn layer 2 is formed by braiding under the condition of double-plied yarn-20 shots. A performance test was performed on this reinforcing hose as in the example, and the results are shown in Table 2. (Comparative Example 2) A polyester yarn made of the same reinforced PE as in the example is braided under the condition of 3 combined yarns-24 strokes to form the upper yarn layer 4 and has the same configuration as the example. is there. A performance test was performed on this reinforcing hose as in the example, and the results are shown in Table 2. (Comparative Example 3) Tensile strength of 8.7 g, elongation of 14.0%, elongation of 4.0% under a load of 3 g per unit denier, and 150
A polyester yarn of 0 denier is braided under the condition of two-plied yarn-20 beats to form the lower yarn layer 2, and the same yarn is braided under the condition of three-plied yarn-24 hits and the upper yarn layer. The structure is the same as that of the embodiment except that the structure No. 4 is formed. In addition,
The material of this polyester yarn is usually called PE below.

Performance tests were conducted on this reinforcing hose in the same manner as in the examples, and the results are shown in Table 2. (Comparative Example 4) The configuration is the same as that of the example, except that the polyester yarn made of normal PE is braided under the condition of double-plied yarn-20 shots to form the lower yarn layer 2.

A performance test was conducted on this reinforcing hose in the same manner as in the example, and the results are shown in Table 2.

[0019]

[Table 2] From Table 2, it can be seen that only in the case of the constitution of the present invention, the fatigue resistance and the volume expansion amount are good, and the high-pressure hose has sufficient performance. It is clear that this is due to the use of polyester yarn having a predetermined characteristic value for the lower yarn layer and vinylon yarn for the upper yarn layer.

[0020]

That is, according to the reinforcing hose of the present invention,
It has excellent fatigue resistance during repeated pressurization and repeated bending, thus improving durability, and can reliably transmit fluid pressure due to a small volume change during pressurization.

[Brief description of drawings]

FIG. 1 is a structural explanatory view of a reinforcing hose according to an embodiment of the present invention.

[Explanation of symbols]

1: Tube rubber layer 2: Lower thread layer 3: Intermediate rubber layer 4: Upper thread layer 5: Cover rubber layer

Claims (1)

[Claims] 1. A reinforcing hose comprising an inner tube rubber layer and a cover rubber layer, and having at least two reinforcing thread layers consisting of an upper thread layer and a lower thread layer in an intermediate layer between the respective rubber layers, wherein the lower thread is The yarns constituting the layers have characteristic values such that the tensile strength per unit denier is 8 g or more, the elongation is 10 ± 1.5%, and the elongation at the time of 3 g load per unit denier is 2.7 ± 1.0%. A reinforced hose characterized in that the yarn is a polyester yarn, and the yarn forming the upper yarn layer is a vinylon yarn.