JPH06201076A - Reinforced hose - Google Patents

Abstract

PURPOSE:To heighten fatigue resistance and reduce the quantity of cubic expansion by using polyester yarn with specific characteristic value for the lower yarn layer and upper yarn layer of a reinforcing yarn layer provided between an inner tube rubber layer and a cover rubber layer, and braiding at least the lower yarn layer in a specific count condition. 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 the end part is provided with a mouthpiece 6. In this case, polyester yarn is used as the yarn forming the lower yarn layer 2 and upper yarn layer 4, 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%. At least the lower yarn layer 2 is then braided in a count condition selected out of double yarn-24 count, triple yarn-20 count and triple yarn-24 count.

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 in which a reinforcing yarn layer is 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 that time, it was discovered that the characteristics are particularly improved by using the polyester reinforcing yarn for the upper yarn layer. Furthermore, they have completed the present invention by finding that their characteristics are further improved by increasing the number of driven lower thread layers.

That is, the reinforcing hose of the present invention comprises 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 yarns constituting the lower yarn layer and the upper yarn layer have a tensile strength per unit denier of 8 g or more,
A polyester yarn having a characteristic value of an elongation of 10 ± 1.5% and an elongation at a load of 3 g per unit denier of 2.7 ± 1.0%, and at least the lower yarn layer has two polyester yarns. It is characterized in that it is braided under the driving conditions selected from -24 shots, 3 plied yarns-20 shots and 3 plied yarns-24 shots.

When the tensile strength per unit denier of the polyester yarns constituting the lower yarn layer and the upper yarn layer is less than 8 g, sufficient rupture strength cannot be obtained in the reinforcing hose and the elongation is more than 8.5%. If it is small, sufficient 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. Also,
Elongation exceeds 11.5%, 3g per unit denier
If the elongation under load is less than 1.7%, other characteristic values of the reinforcing yarn will be out of the above range, and the same problem will occur in the reinforcing hose.

Further, the driving conditions of the polyester yarn for forming at least the lower yarn layer are as follows.
It is selected from three-ply 20 yarns and three-ply-24 yarns.
When the amount of the driven yarn is less than this, the fatigue resistance and the like become insufficient, and when the amount is more than this, the amount of the yarn is too large and the unevenness of the surface of the reinforcing yarn layer becomes severe and the performance of the hose deteriorates. Although the conditions for driving the upper yarn layer are not particularly limited, it is optimal to select from two-ply composite yarn-24, three-ply composite yarn-20, and three-ply composite yarn-24, like the lower yarn layer. By using the high-strength polyester yarn also in the upper yarn layer, excellent fatigue resistance can be obtained.

[0011]

In the reinforcing hose of the present invention, the yarns constituting the lower yarn layer and the upper yarn layer have a tensile strength per unit denier of 8 g.
Above, elongation is 10 ± 1.5%, 3g per unit denier
A polyester yarn having a characteristic value of an elongation under load of 2.7 ± 1.0%, and at least a lower yarn layer is a two-ply composite yarn-24
It is braided under the driving conditions selected from striking, 3-ply yarn-20 shots, and 3-ply yarn-24 shots.

With such a structure, the reinforcing hose of the present invention can achieve both excellent fatigue resistance and small volume expansion.

[0013]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples. (Embodiment 1) 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 an innermost tube rubber layer 1, a lower thread layer 2 braided on the surface of the tube rubber layer 1, an intermediate rubber layer 3 covered on the lower thread layer 2 surface, It is composed of an upper thread layer 4 braided on the surface of the intermediate rubber layer 3 and a cover rubber layer 5 covered on the surface of the upper thread layer 4, and a cap 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-plied yarn-24 strokes. This polyester yarn has a tensile strength of 9.0.
g, the elongation is 10.0%, and the elongation at a load of 3 g per unit denier is 2.7%. Hereinafter, the material of this polyester yarn is referred to as reinforced PE.

The intermediate rubber layer 3 is made of NR. The upper yarn layer 4 is also composed of the above-mentioned reinforced PE, and is a three-ply yarn-
It is formed by braiding under the condition of 24 strokes. 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 105 kgf / c based on JIS2601.
The amount of change in internal volume of a hose with a free length of 305 mm when pressurized with m ² was measured. For the fatigue resistance, a test of repeatedly bending while applying a pressure of 100 kgf / cm ² at 100 ° C. was repeatedly performed, and the number of times of repeated bending when the hose ruptured was measured. (Example 2) The same as Example 1 except that the lower yarn layer 2 was formed by three-ply 20 yarns. A performance test was performed on this reinforcing hose as in Example 1, and the results are shown in Table 2. (Example 3) Example 3 is the same as Example 1 except that the lower yarn layer 2 was formed by three-ply composite yarn-24 strokes. A performance test was performed on this reinforcing hose as in Example 1, and the results are shown in Table 2. (Comparative Example 1) The same as Example 1 except that the polyester thread made of the same reinforced PE as in Example 1 was braided under the condition of 20 double stitches to form the lower thread layer 2. It is a composition. A performance test was performed on this reinforcing hose as in Example 1, and the results are shown in Table 2. (Comparative Example 2) Tensile strength of 8.7 g, elongation of 14.0%, elongation of 3% per unit denier of 4.0%, 150%
A polyester yarn of 0 denier (usually PE) is braided under the condition of two-plied yarn-20 shots to form the lower yarn layer 2, and the same yarn is braided under the condition of three-plied yarn-24 shots. The construction is similar to that of the first embodiment except that the upper thread layer 4 is formed. A performance test was performed on this reinforcing hose as in Example 1, and the results are shown in Table 2. (Comparative Example 3) 1200 denier vinylon yarns are braided under the condition of two-plied yarns -20 shots to form a lower yarn layer 2, and these vinylon yarns are braided under the conditions of three-plied yarns -24 shots. The structure is the same as that of the first embodiment except that the thread layer 4 is formed. A performance test was performed on this reinforcing hose as in Example 1, and the results are shown in Table 2.

[0016]

[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 apparent that this is due to the fact that a polyester thread having a predetermined characteristic value is braided at a predetermined number of threads in the lower thread layer and the polyester thread is also used in the upper thread layer.

[0017]

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 yarn constituting the layer and the upper yarn layer has a tensile strength per unit denier of 8 g or more, an elongation of 10 ± 1.5%,
Elongation at 3g load per unit denier is 2.7 ± 1.0
% Polyester yarn having a characteristic value of at least the lower yarn layer, wherein the polyester yarn is under the driving conditions selected from two-ply composite yarn-24, three-ply composite yarn-20, and three-ply composite yarn-24. Reinforced hose characterized by being braided.