JPH063273B2 - High pressure hose - Google Patents

Description

TECHNICAL FIELD The present invention relates to a high pressure hose having a reinforcing metal wire layer between an inner rubber tube and an outer rubber layer, and more particularly to a high pressure hose having excellent durability. is there.

As a high-pressure hose having a reinforcing metal wire layer, a high-pressure hose having a plurality of reinforcing metal wire layers formed by braiding metal wires between an inner rubber tube and an outer rubber layer, and an inner rubber tube A high-pressure hose having a plurality of reinforcing metal wire layers which are alternately spirally wound in opposite left and right directions between the outer rubber layer and the outer rubber layer is known.

Problems to be Solved by the Invention However, it is extremely rare that the high-pressure hose having such a structure breaks due to fatigue of the reinforcing metal wire layer in the main body during actual use or during a fatigue test. , In practice, the outermost reinforcing metal wire layer near the joint fitting crimped to the end of the hose wears due to the contact relationship with the fitting fitting or the friction sliding contact relationship between the metal wires. In most cases, it is destroyed in parts.

As a measure for preventing such breakage, not only the outermost reinforcing metal wire layer but also the inner rubber tube is removed to expose the innermost reinforcing metal wire layer, and the fitting metal fitting is attached to that portion. By crimping, the reinforcing metal wire layer is compressed and deformed,
By attaching fittings to the end of the hose or increasing the diameter of all metal wires in the reinforcing metal wire layer,
The timing of breaking the metal wire due to wear was delayed.

However, the former method requires the use of specially shaped fittings that are more expensive than those that are commonly used, and the work of stripping the end of the hose is more troublesome than before, so the product price In the latter method, the strength of the main body of the hose is unnecessarily large and the quality is excessive, so that there is a drawback that the product price is also increased.

Means and Actions for Solving the Problems An object of the present invention is to provide a high pressure hose which can use commonly used fittings and has good durability without excessive quality.

The purpose of this is to provide a high-pressure hose having a plurality of reinforcing metal wire layers formed by braiding metal wires between an inner rubber tube and an outer rubber layer. By making the wire diameter larger than the metal wire diameter of the other reinforcing metal wire layers, or between the inner rubber tube and the outer rubber layer, spiral winding is performed in the opposite left and right directions. In a high-pressure hose having a plurality of reinforcing metal wire layers, the metal wire diameters of the pair of reinforcing metal wire layers located on the outermost side and the inner side thereof are made larger than the metal wire diameters of the other reinforcing metal wire layers. To be achieved.

In the first invention of the present application, the diameter of the metal wire of the braid structure in the outermost reinforcing metal wire layer is made larger than the diameter of the metal wire in the other reinforcing metal wire layers. Similarly, in the second invention of the present application, not only the outermost spiral-wound reinforcing metal wire layer, but also the second reinforcement which is paired therewith and spirally wound in the opposite direction is used. The diameter of the metal wire in the metal wire layer is also increased. The reason is that if only one of the paired metal wires has a large diameter, the difference in expansion and deformation between the two becomes excessive when a high fluid pressure is applied to the high-pressure hose, causing “kink” in the main body of the hose. This is because it will occur.

According to such a configuration of the present invention, since the metal wire diameter of the outermost reinforcing metal wire layer that is in direct contact with the joint fitting is large, it is possible to delay the breakage time due to wear and improve the durability.

Embodiment An embodiment of the present invention shown in FIGS. 1 to 3 will be described below.

FIG. 1 shows the high-pressure hose 10 in a state in which the inner layer and the outer layer are successively peeled off, and FIG. 2 shows a cross section along the longitudinal direction. The high-pressure hose 10 has a rubber tube inside
Between the outer layer 12 and the outer rubber layer 14, there are four layers of reinforcing metal wire layers, and on the outer periphery of the inner rubber tube 12, a first reinforcing metal wire layer in which a steel wire 16a is spirally wound ( Innermost reinforcing metal wire layer) 16 is provided, and a steel wire 20a having the same diameter as the steel wire 16a is spirally wound in the opposite direction to the steel wire 16a on the outer side of the rubber-impregnated woven fabric 18 wound around the outer circumference thereof. The second reinforcing metal wire layer 20 is provided, and the steel wires 16a, 20 are provided on the outer side of the rubber-impregnated woven fabric 22 wound around the outer circumference thereof.
A third reinforcing metal wire layer 24 formed by spirally winding a steel wire 24a having a larger diameter than that of the steel wire 24a in a direction opposite to that of the steel wire 24a is provided. Outside, steel wire 24a
A fourth reinforcing metal wire layer 28 is provided by spirally winding a steel wire 28a having the same diameter as that of the steel wire 24a in the opposite direction to the steel wire 24a.
An outer rubber layer 14 is covered with a rubber-impregnated woven cloth 30 on the outside of the.

To attach the fitting metal fitting 40 composed of the fitting body tube 42 and the outer tube 44 to the high pressure hose 10, the outer rubber layer 14 and the rubber-impregnated woven cloth 30 are cut off, and the fitting body tube is attached to the end of the high pressure hose 10. 42 is inserted, and the outer cylinder 44 fitted to the outer side is reduced in diameter by crimping (caulking process), and thus the third cylinder
As shown in the figure, the end of the stripped high-pressure hose 10 is clamped between the joint body cylinder 42 and the outer cylinder 44 with strong pressure.

Test Example A high-pressure hose (referred to as high-pressure hose A) 10 having the above structure was subjected to an impact pressure test (JIS) to see how durable it was. Fig. 6 shows the pressure waveform. A maximum pressure of 450 kg / cm ² is applied every ^{second, and} after applying the maximum pressure, the reference pressure of 300 kg for about 0.5 seconds.
/ cm ² ) is applied and then the pressure is released.

Also, for comparison, in contrast to the high pressure hose B (see FIG. 4) and the high pressure hose 10 (high pressure hose A) of the conventional structure having the reinforcing metal wire layers in which the metal wire diameters of all four layers are the same, , A comparative example high-pressure hose C in which the metal wire diameter in the inner two-layer reinforcing metal wire layers is larger than that in the outer two-layer reinforcing metal wire layers
An impact pressure test was also conducted on (see FIG. 5), and these are shown in Table 1.

In Table 1, hose inner diameter d ₁ and reinforcing metal wire layer outer diameter
d ₂ and the tightening outer diameter D are the dimensions shown in FIGS. 2 to 5, and the tightening amount (%) is the case where the thick part of (d ₂ −d ₁ ) / 2 is tightened with the fitting. Shows the compression ratio of. If this compression rate is small, the fitting will easily come off,
If it is too large, the inner rubber tube is likely to break. Then, in conducting the test, it is usual to appropriately vary the tightening amount (%) in consideration of variations in hose dimensions and joint fitting dimensions.

<Evaluation> The static breaking pressures of the high-pressure hoses A, B, and C are almost equal, but the metal wire diameter in the two inner reinforcing metal wire layers is compared with the metal wire diameter used in the conventional high-pressure hose B. However, the number of times of impact pressure application of the high-pressure hose A of the present invention in which the metal wire diameter in the two outer reinforcing metal wire layers is large is smaller than that of the other high-pressure hoses B and C. It is remarkably large, and according to the present invention, it is clear that the durability of the joint fitting attachment portion, that is, the durability of the high pressure hose is significantly improved.

Effect of the Invention As is clear from the above description, in the present invention, in the high-pressure hose having a plurality of reinforcing metal wire layers, the reinforcing metal wire layer located at the outermost position (in the spiral wound type, The metal wire diameter of the reinforcing metal wire layer (including the reinforcing metal wire layer) is made larger than that of other reinforcing metal wire layers, so the wear breakage time in the contact relationship with the joint fitting is delayed, and durability as a high pressure hose Improvements may be contemplated.

[Brief description of drawings]

FIG. 1 is a side view of a high-pressure hose according to an embodiment of the present invention showing a partial cutaway view, FIG. 2 is a cross-sectional view taken along its lengthwise direction, and FIG. Cross section of the main part,
FIG. 4 is a sectional view similar to FIG. 2 of a known high pressure hose, FIG. 5 is a sectional view similar to FIG. 2 of a high pressure hose as a comparative example, and FIG. 6 is a pressure waveform of an impact pressure test. FIG. 10 ... High pressure hose, 12 ... Inner rubber tube, 14 ... Outer rubber layer, 16 ... First reinforcing metal wire layer, 16a ... Steel wire, 18 ... Rubber impregnated woven cloth, 20 ... Second reinforcing metal wire layer, 20a ... Steel line,
22 ... Rubber impregnated woven fabric, 24 ... Third reinforcing metal wire layer, 24a
... Steel wire, 26 ... Rubber impregnated woven fabric, 28 ... Fourth reinforcing metal wire layer, 28 ... Steel wire, 30 ... Rubber impregnated woven fabric, 40 ... Joint fitting, 42 ... Joint body cylinder, 44 ... Outer cylinder.

Claims (2)

[Claims] 1. A high-pressure hose having a plurality of reinforcing metal wire layers formed by braiding metal wires between an inner rubber tube and an outer rubber layer, wherein the reinforcing metal wire layer located on the outermost side is A high-pressure hose having a metal wire diameter larger than those of other reinforcing metal wire layers. 2. A high-pressure hose having a plurality of reinforcing metal wire layers spirally wound in opposite left and right directions alternately between an inner rubber tube and an outer rubber layer, and is located on the outermost side and inside thereof. A high-pressure hose in which the metal wire diameter of the pair of reinforcing metal wire layers is larger than the metal wire diameters of the other reinforcing metal wire layers.