JP5798805B2 - High pressure hose - Google Patents

Description

  The present invention relates to a high-pressure hose that is employed in piping on which hydraulic pressure, hydraulic pressure, air pressure, or the like acts.

The high-pressure hose is used in various industrial fields because it is convenient for pumping various pressurized liquids and gases. For example, the high-pressure hose can be suitably used as a pipe for pumping hydraulic oil of a hydraulic pump to the operating portion.
In this type of high-pressure hose, a metal wire reinforcing layer is formed by winding a metal wire in a spiral shape or a lattice shape on the surface of the inner tube tube, and alternately turns the wire in the winding direction. What has a lamination reinforcement layer constituted by laminating while changing is known. In this way, by stacking a plurality of metal wire reinforcing layers to form a laminated reinforcing layer, a high-pressure hose with improved durability can be obtained.

However, in the high-pressure hose provided with the laminated reinforcing layer as described above, the innermost metal wire reinforcing layer (the first innermost wire reinforcing layer) in the radial direction and in contact with the inner tube is the innermost. A greater pressure is applied than the metal wire reinforcement layer (second and subsequent wire reinforcement layers) located on the radially outer side of the inner wire reinforcement layer. Therefore, it is known that the innermost wire reinforcing layer is easily fatigued and broken in the high-pressure hose provided with the laminated reinforcing layer.
Here, since a wire having a circular cross section is generally adopted for the metal wire constituting the wire reinforcement layer, the wire constituting the innermost wire reinforcement layer and the outer side (second layer from the inside) are used. The wires constituting the wire reinforcing layer are in point contact with each other in the radial direction inside and outside (up and down) at the intersecting portion. Therefore, the high-pressure hose has a disadvantage that stress concentrates on the cross portion, and the wire of the innermost wire reinforcing layer tends to break (break) particularly from this portion.

  Therefore, a technique for dealing with the above inconvenience has been studied, and for example, a technique according to Patent Document 1 has been proposed. Patent Document 1 discloses a high-pressure hose in which the wire cross-sectional area of the innermost wire reinforcing layer provided on the inner tube is set larger than the cross-sectional areas of the wires of the other wire reinforcing layers. According to the technique disclosed in Patent Document 1, since the wire of the innermost wire reinforcement layer has a larger cross-sectional area than other wires and the rigidity is improved, the progress of fatigue of the innermost wire reinforcement layer that receives a large pressure is delayed and the hose Durability can be improved.

JP 2005-308114 A

However, in order to enhance the durability performance of the high-pressure hose, as disclosed in Patent Document 1, if the cross-sectional area of the wire constituting the wire reinforcing layer is increased, that is, if the wire is simply thickened, the rigidity of the entire hose becomes excessively high. Flexibility may be impaired. As a result, there is a concern that the hose is excellent in durability but difficult to handle.
Accordingly, an object of the present invention is to provide a high-pressure hose that has improved durability without impairing the flexibility of the hose.

The above object is a high pressure hose provided with a laminated reinforcing layer formed by laminating a plurality of metal wire reinforcing layers on the surface of the inner tube,
A second metal wire reinforcement layer is disposed on the outside of the first metal wire reinforcement layer disposed on the inner side closest to the inner tube, in contact with the first metal wire reinforcement layer;
Wherein the second wire constituting the second metallic wire reinforcement layer, Ri said first first tare and pressure receiving surface is formed to receive a pressing force from the wire constituting the metal wire reinforcement layer,
Cross-sectional shape of the first wire Ru circular der, it can be achieved by high pressure hose, characterized in.

Then, the second wire is and the cross-sectional shape has at least the pressure receiving surface is preferably a non-circular shape.
Here, the non-circular shape is a shape other than a perfect circle that can achieve the object of the present invention, and examples of the non-circular shape include a crescent moon shape, a cat-eye shape, an elliptical shape, a flat shape, and a semicircular shape. included. The non-circular shape is preferably any one selected from an elliptical shape, a flat shape, and a semicircular shape.

  The tensile strength of the first wire is preferably set larger than the tensile strength of the second wire.

  And the curvature radius which prescribes | regulates the curvature in the wire cross section of the contact surface of the said 1st wire contacted to the said pressure receiving surface of the said 2nd wire is the curvature in the wire cross section of the said pressure receiving surface. It is desirable to set it smaller than the specified radius of curvature.

  In the high-pressure hose according to the present invention, the first wire of the innermost wire reinforcing layer that receives a large stress from the inner tube side is reinforced by the second wire positioned outside the first wire. In particular, a pressure receiving surface is formed on the second wire, and the first wire can be received by the pressure receiving surface, thereby dispersing the stress received by the first wire and causing fatigue. Destruction can be suppressed. Therefore, since the breakage of the first wire can be prevented without increasing the rigidity by increasing the thickness of the wire as in the prior art, it is possible to provide a high-pressure hose excellent in handleability.

It is the cross-sectional view which showed one example of the high pressure hose which concerns on this invention.

Hereinafter, an embodiment according to the present invention will be described in detail with reference to the drawings.
The present invention provides a high-pressure hose provided with a laminated reinforcing layer formed by laminating a plurality of metal wire reinforcing layers on the outer peripheral surface of an inner tube, and is disposed on the radially innermost side of the laminated reinforcing layer closest to the inner tube. In order to overcome the problem that the wire (first wire) constituting the first wire reinforcing layer is easily fatigued, the above-described technical problem is solved by changing to a laminated reinforcing layer having the following structure. It is improved. In the high-pressure hose according to the present invention, the number of metal wire reinforcement layers is not particularly limited. For example, 2 to 10 metal wire reinforcement layers may be laminated. Furthermore, in the high-pressure hose according to the present invention, there is no particular limitation on the winding method of the wire constituting the metal wire reinforcing layer, and the wire may be wound in a spiral shape or a blade (lattice). It may be wound in a shape.

  FIG. 1 is a cross-sectional view showing a cross section of a high-pressure hose 1 according to an embodiment of the present invention (a cross section in a direction perpendicular to the central axis of the hose). The high-pressure hose 1 is, for example, a NBR-based compound ( On the surface of a cylindrical inner tube 11 made of a compound, a laminated reinforcing layer 12 is formed by sequentially laminating four metal wire reinforcing layers 12a, 12b, 12c, and 12d from the inside. Here, preferably, the outer side (radially outer side) of the laminated reinforcing layer 12 shown in FIG. 1 is further covered with an outer skin 13 made of, for example, nylon (polyamide fiber) to form the high-pressure hose 1.

In the high-pressure hose 1 according to the present invention, the radially outer side of the first metal wire reinforcement layer (innermost wire reinforcement layer) 12a disposed on the outer peripheral surface side of the inner tube 11 (innermost side of the laminated reinforcement layer 12). Further, a second metal wire reinforcement layer 12b is disposed in contact with the first metal wire reinforcement layer 12a. The second wire 12b-w constituting the second metal wire reinforcing layer 12b has a pressure receiving surface that receives a pressing force from the first wire 12a-w constituting the first metal wire reinforcing layer 12a. 12b-fc is formed. As a result, the first wire 12a-w and the second wire 12b-w are in a cross-sectional view of the high-pressure hose 1 at the time of pumping than when wires having a circular cross-sectional shape are in contact with each other. Even surface contact on a wide surface. That is, for example, when liquid or gas is pumped at a pressure of 40 MPa or more, the first wires 12a-w bite into the pressure receiving surfaces 12b-fc of the second wires 12b-w located on the radially outer side. Wide surface contact. Therefore, in the high-pressure hose 1, the stress that the first wires 12 a-w receive from the inner tube 11 can be dispersed to suppress the occurrence of fatigue fracture.
Note that the high-pressure hose 1 according to the present invention does not increase the rigidity of the wire by using a thicker wire to prevent fatigue fracture, and the first wire 12a-w is replaced with the outer second wire 12b-w. Since the configuration that dares to bite in is adopted, the durability of the hose can be improved without causing inconvenience that the rigidity becomes too high and the handling property is deteriorated.

  Here, in the high-pressure hose 1, the first wire 12a-w has a circular cross-sectional shape, and the second wire 12b-w has a non-circular shape having at least a pressure receiving surface 12b-fc. The shape is preferable. The non-circular shape includes, for example, a crescent shape, a cat-eye shape, an elliptical shape, a flat shape, a semicircular shape, and the like, but the cross-sectional shape of the second wire 12b-w includes an elliptical shape, a flat shape, and a semicircular shape. Any shape selected from circular shapes is preferred. This is because a wire having an elliptical, flat, or semicircular cross-sectional shape can be easily obtained by wire processing.

When the above configuration is adopted, the first wires 12a-w are formed by making the second wires 12b-w constituting the second layer (second metal wire reinforcing layer), for example, flat or elliptical. As the surface (pressure receiving surface 12b-fc) from the point of simply crossing the portion where the second wire 12b-w contacts, the stress applied to the first layer (innermost wire reinforcing layer) on the outer (back) side It is possible to efficiently disperse in the two layers and to suppress the breakage of the first wires 12a-w.
In addition, by making the second wire 12b-w a non-circular shape such as a flat shape or an elliptical shape, the increase in thickness in the hose radial direction can be suppressed even if the cross-sectional area is increased. Can be obtained.
In the prior art, the first layer (innermost wire reinforcing layer) and the wires constituting the second layer disposed outside the first layer are generally circular in shape. The wire has a circular shape, and the second wire constituting the second layer outside the wire has a non-circular shape. Here, the first wire has a circular shape from the viewpoint of improving the durability performance of the high-pressure hose, as a first layer wire that bears the most tension, a circular wire having excellent strength and fatigue resistance is used. It is because it is preferable to use. That is, in order to increase the durability of the high-pressure hose, it is necessary to use a circular wire having excellent strength and fatigue resistance for the first layer because it is obtained by uniform processing.

  In the high-pressure hose 1, the radius of curvature that defines the curvature in the wire cross section of the contact surface of the first wire 12 a-w that contacts the pressure receiving surface 12 b-fc of the second wire 12 b-w is It is preferable to make it smaller than the curvature radius which prescribes | regulates the curvature in the wire cross section of the receiving surface 12b-fc. This is because when the inventor of the present application scrutinized the cross portion of the first wire and the second wire, the radius of curvature defining the curvature of the wire cross-section of the contact surface of the first wire is set to the pressure receiving surface. Based on the fact that the indentation of the cross portion of the first wire is reduced and the breaking strength of the first wire is improved when the curvature radius is smaller than the radius of curvature defining the curvature of the wire cross section. .

As a specific example when this condition is satisfied, the cross-sectional shape of the first wire 12a-w is a circular shape, and the cross-sectional shape of the second wire 12b-w is an elliptical shape, a flat shape, or the like. It is preferable that In this case, the surface of the second wire 12b-w facing the first wire 12a-w is the pressure receiving surface 12b-fc described above.
In addition, what is called a flat shape in the specification of the present application is a shape having a parallel surface facing the top and bottom by crushing the circular shape from above and below. When the cross-sectional shape of the second wire 12b-w is the flat shape, the pressure receiving surface 12b-fc is a flat surface on one side, and in this case, the curvature radius defining the flat surface is infinite (∞ ). Further, when the cross-sectional shape is a circular shape, the radius of the circle is the radius of curvature.

The maximum value of the radius of curvature that defines the curvature of the contact surface of the first wire 12a-w in the wire cross section is R1, and the wire cross section of the pressure receiving surface 12b-fc of the second wire 12b-w R1 is preferably smaller than R2, where R2 is the maximum value of the radius of curvature that defines the curvature at. And it is especially preferable to set it as R2-R1> = 0.02mm. It is preferable to set such a range so that the stress applied to the first layer (innermost wire reinforcing layer) is particularly efficiently dispersed by the outer second layer to break the first wire 12a-w. This is because it can be sufficiently suppressed.
Moreover, since the thickness of the second wire reinforcing layer is reduced, the product weight is not increased, and flexibility can be maintained, the second wires 12b-w constituting the second wire reinforcing layer can be maintained. It is preferable that the cross-sectional shape is a non-circular shape such as an elliptical shape or a flat shape.
Furthermore, in order to reduce the gauge of the product and keep flexibility, the cross-sectional area of the third and subsequent outer layers arranged outside the second wire reinforcing layer is the first layer wire. It is preferable to employ a material having a smaller cross-sectional area.

The wire having an elliptical cross-sectional shape can be obtained by drawing using an elliptical die, and the flat wire can be obtained by a production method such as rolling a circular wire with a roll.
Furthermore, in the high-pressure hose 1 according to the present invention, it is desirable that the tensile strength of the first wires 12a-w is set to be equal to or higher than the tensile strength of the second wires 12b-w. In the present invention, it is preferable to use a high carbon steel wire as the wire, and it is preferable to use a high carbon steel wire having a tensile strength of 2800 MPa or more, more preferably a tensile strength of 3000 MPa or more as the first wires 12a-w. desirable.

[Example]
High pressure hoses of Examples 1 to 7 according to the present invention were manufactured under the conditions shown in Table 1 below. For comparison, the high pressure hose of Comparative Examples 1 and 2 having no pressure receiving surface was produced by changing the conditions. And the performance of each hose was evaluated.
Specifically, as an inner tube, a tube (inner diameter: 25 mm, outer diameter: 28 mm) made of a compound (compound) based on NBR is prepared, and the outer surface of the inner tube tube is shown in Table 1. A laminated reinforcing layer composed of four metal wire reinforcing layers of various specifications was provided to make a high-pressure hose, and the hose performance was evaluated.
In addition, the material of the wire which comprises each metal wire reinforcement layer shall be a high carbon steel wire, and the cross-sectional shape of the wire which comprises each metal wire reinforcement layer comprises the 2nd layer about Examples 1-7 Only the second wire is non-circular (flat, elliptical), and the other is circular.
Incidentally, the curvature radius of Example 3 using a wire with an elliptical cross section as the second wire is the maximum value of the curvature radius on the pressure receiving surface.

In the following Table 1, the number of driving is the number of the first wires arranged on the outer surface of the inner tube as the first metal wire reinforcing layer, or the first metal made as the second metal wire reinforcing layer. It is the number of the 2nd wires arrange | positioned on a wire reinforcement layer.
The breaking pressure (MPa) of the hose was measured according to JIS K6330-2.
Furthermore, the total wire cross-sectional area (S1 × T1 + S2 × T2) of the first metal wire reinforcement layer and the second metal wire reinforcement layer corresponds to the bending hardness of the hose. The breaking pressure / (S1 × T1 + S2 × T2), which is obtained by dividing the hose breaking pressure by the total cross-sectional area of the wire, is a guideline indicating the flexibility of the produced hose against pressure resistance. Excellent flexibility.
In addition, this value set 3.9 or more as the pass.

  As described above, according to the present invention, the first wire can be prevented from being broken without increasing the rigidity by increasing the thickness of the wire, so that a high-pressure hose excellent in handleability can be provided.

  As is apparent from the above description, according to the present invention, it is possible to provide a high-pressure hose applicable not only to hydraulic piping but also to pumping various liquids and gases.

DESCRIPTION OF SYMBOLS 1 High pressure hose 11 Inner tube tube 12 Laminated reinforcement layer 12a 1st metal wire reinforcement layer 12b 2nd metal wire reinforcement layer 12c 3rd metal wire reinforcement layer 12d 4th metal wire reinforcement layer 12a-w First wire 12b-w Second wire 12b-fc Pressure receiving surface 13 Outer skin

Claims (5)

A high pressure hose provided with a laminated reinforcing layer formed by laminating a plurality of metal wire reinforcing layers on the surface of the inner tube,
A second metal wire reinforcement layer is disposed on the outside of the first metal wire reinforcement layer disposed on the inner side closest to the inner tube, in contact with the first metal wire reinforcement layer;
Wherein the second wire constituting the second metallic wire reinforcement layer, Ri said first first tare and pressure receiving surface is formed to receive a pressing force from the wire constituting the metal wire reinforcement layer,
The cross-sectional shape of the first wire Ru circular der, high pressure hose, characterized in that. The high-pressure hose according to claim 1, wherein the second wire has at least the pressure receiving surface and has a non-circular cross-sectional shape.   The high-pressure hose according to claim 2, wherein the non-circular shape is any one selected from an elliptical shape, a flat shape, and a semicircular shape.   The high-pressure hose according to any one of claims 1 to 3, wherein the tensile strength of the first wire is larger than the tensile strength of the second wire.   The radius of curvature defining the curvature of the wire cross section of the contact surface of the first wire that contacts the pressure receiving surface of the second wire defines the curvature of the pressure receiving surface of the wire cross section of the wire. The high-pressure hose according to claim 1, wherein the high-pressure hose is smaller than a curvature radius.

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