JP2018150980A - High pressure hose - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high pressure hose using a steel cord formed by twisting steel filaments as a reinforcement material, and having excellent impact durability.SOLUTION: At least a first steel wire rod reinforcement layer 11a and a second steel wire rod reinforcement layer 11b are steel cord reinforcement layers including steel cords formed by twisting a plurality of steel filaments, a first convex angle θobtained by connecting a center point of a steel filament positioned at a hose radial outermost portion of the first steel wire rod reinforcement layer 11a and a center point of the steel filaments disposed on both sides in the same layer as the steel filament, is 108° or more, a second convex angle θobtained by connecting a center point of the steel filament positioned on a hose radial innermost portion of the second steel wire rod reinforcement layer 11b and a center point of the steel filaments disposed on both sides in the same layer as the steel filament is 108° or more, and the interval between them is 1 mm or less.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a high-pressure hose, and particularly relates to a high-pressure hose excellent in impact durability.

  Generally, a high-pressure hose having flexibility used for a power steering hose of a construction machine, a machine tool, an automobile, or a measuring instrument is provided with an inner rubber layer and a plurality of reinforcing layers on the outer periphery thereof. The reinforcing material of the high-pressure hose provided with this reinforcing layer usually uses fibers such as steel filament, nylon, and polyester. For example, in the case of a high-pressure hose having a four-layer structure, right-handed and left-handed It is wound so as to alternate.

  As a technique related to the improvement of such a high-pressure hose, Patent Literatures 1 to 6 can be cited. It is also known for high-pressure hoses to place intermediate rubber between reinforcing layers. For example, Patent Document 7 discloses that the gas permeation resistance of the barrier layer formed of a resin film of polyvinyl alcohol is not lowered, and the gas permeation resistance of the barrier layer can be sufficiently exhibited to suppress gas permeation well. A low gas permeability hose that can be used has been proposed. Further, Patent Document 8 proposes a high-pressure hose that has a small internal pressure and impact pressure drop due to a high temperature, is flexible, and has a low bending rigidity by providing a specific intermediate layer between the multilayer spiral filament reinforcing layers. .

JP 2012-036927 A JP 2008-002637 A JP 2001-041361 A Japanese Utility Model Publication No. 01-104495 JP 09-137392 A Japanese Patent Application Laid-Open No. 08-027686 JP 2008-248995 A JP 60-143286 A

  Here, since the bending rigidity of the steel filament is proportional to the fourth power of the diameter, the steel cord obtained by twisting thin steel filaments is more flexible when compared with the same cross-sectional area. Moreover, since the strength per cross-sectional area becomes harder to obtain with a steel filament of 0.4 mm or more, the strength is easier to obtain by twisting steel filaments with a diameter of 0.4 mm or less, and the weight can be reduced. Therefore, when a product such as a tire that requires flexible and high strength performance is reinforced with steel, a steel cord in which thin steel filaments are twisted is used.

  Conventionally, the reinforcement of a high-pressure hose does not require both strength and flexibility as much as a tire, and therefore, a steel cord that requires a man-hour of twisting steel filaments is generally not used. However, in order to give high strength and flexibility to high pressure hoses used at higher pressures, there are limits to single wire steel filaments, and steel filaments that are also used for tire reinforcement in high pressure hoses. Application of steel cord twisted together is conceivable. However, a high pressure hose using a steel cord twisted with steel filaments as a reinforcing material has a new problem that impact durability may not be sufficiently improved.

  Therefore, an object of the present invention is to provide a high-pressure hose excellent in impact durability while using a steel cord obtained by twisting steel filaments as a reinforcing material.

  As a result of intensive studies to solve the above problems, the present inventors have obtained the following knowledge. That is, as a result of observing the breaking mode of the high-pressure hose, it was found that the steel cord reinforcing layer was separated. In particular, the peeling between the first and second layers of the steel cord reinforcing layer, which is the innermost steel cord reinforcing layer, is large, but the peeling does not occur between the steel cord and the rubber, but in the middle The starting point was in the rubber. Such peeling was not observed when a normal steel filament was used with a single wire. Based on this knowledge, the inventors of the present invention have made further studies. As a result, the steel cord twisted with the steel filament has irregularities due to the knitting on the surface thereof. The stress is repeatedly concentrated between the convex portions of each other, cracks are generated in the rubber, and the rubber is enlarged and peeled off. And when this convex part was sharper, it discovered that a stress concentrated between convex parts and it was easy to generate | occur | produce a crack in an intermediate | middle rubber layer. Therefore, the present inventors have found that the above problem can be solved by setting the structure of the steel cord reinforcing layer as follows, and have completed the present invention.

That is, the high-pressure hose of the present invention is a high-pressure hose having a structure in which a plurality of steel wire reinforcing layers having a spiral structure are laminated.
The first steel wire reinforcing layer, which is at least the innermost steel wire reinforcing layer, and the second steel wire reinforcing layer provided outside the first steel wire reinforcing layer in the hose radial direction twist a plurality of steel filaments. It is a steel cord reinforcement layer that includes steel cords that are combined,
In all the steel cords of the first steel wire reinforcing layer, the center point of the steel filament located at the outermost portion in the hose radial direction in the cross section perpendicular to the cord axis and the same layer as that of the steel filament are arranged on both sides. The first convex angle θ ₁ formed by connecting the center point of the steel filament is 108 ° or more,
In all the steel cords of the second steel wire reinforcing layer, the center point of the steel filament located at the innermost part in the hose radial direction in the cross section perpendicular to the cord axis and the same layer as that of the steel filament are arranged on both sides. The second convex angle θ ₂ connecting the center point of the steel filament is 108 ° or more,
The distance between the steel cord of the first steel wire reinforcing layer and the steel cord of the second steel wire reinforcing layer is 1 mm or less. Here, the steel filament means a single wire that is not twisted, the steel cord means that the steel filament is twisted together, and the steel wire is a broad sense that combines the steel filament and the steel cord. Say.

In the high pressure hose of the present invention, the first convex angle θ ₁ and the second convex angle θ ₂ are preferably 129 ° or more. In the high pressure hose of the present invention, it is preferable that a distance between a steel cord of the first steel wire reinforcing layer and a steel cord of the second steel wire reinforcing layer is 0.6 mm or less. Furthermore, in the high-pressure hose of the present invention, it is preferable that the steel cord has a flat cross section perpendicular to the cord axis direction.

ADVANTAGE OF THE INVENTION According to this invention, the high pressure hose excellent in impact durability can be provided, using the steel cord which twisted the steel filament to the reinforcing material. In the high-pressure hose of the present invention, since the steel cord having a large first convex angle θ ₁ and second convex angle θ ₂ is used, the strain in the rubber between the steel wire reinforcing layers can be alleviated. The distance between the steel cord of the first reinforcing layer and the steel cord of the second reinforcing layer can be reduced. As a result, the outer diameter of the high pressure hose can be reduced. The high-pressure hose of the present invention is suitable for a large-diameter hose having a diameter of 60 mm or more.

It is a section perspective view of the high-pressure hose concerning one suitable embodiment of the present invention. It is explanatory drawing which shows the relationship between the steel cord of a 1st steel wire reinforcement layer, and the steel cord of a 2nd steel wire reinforcement layer.

Hereinafter, the high-pressure hose of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional perspective view of a high-pressure hose according to a preferred embodiment of the present invention. The high-pressure hose 10 of the present invention is a high-pressure hose having a structure in which a plurality of steel wire reinforcing layers 11 having a spiral structure (hereinafter, also simply referred to as “reinforcing layer 11”) are laminated. The layer 11 is laminated via the intermediate rubber layer 12. In the high-pressure hose 10 of the present invention, the reinforcing layer 11 is not limited to the steel wire reinforcing layer, and may include, for example, a reinforcing layer using a cord other than a steel cord such as an organic fiber cord. For example, you may have organic fiber reinforcement layers, such as vinylon, nylon, and PET, inside a steel wire reinforcement layer. The illustrated high-pressure hose 10 includes a tubular inner rubber layer 13 as an innermost layer and a tubular outer rubber layer 14 as an outermost layer. Four layers are formed between the inner rubber layer 13 and the outer rubber layer 14. The steel wire reinforcing layer 11 and the three intermediate rubber layers 12 may be alternately arranged.

  In the high-pressure hose 10 of the present invention, at least a first steel wire reinforcing layer 11a, which is the innermost steel wire reinforcing layer, and a second steel wire reinforcing material provided outside the first steel wire reinforcing layer 11a in the hose radial direction. The layer 11b is a steel cord reinforcing layer including a steel cord formed by twisting a plurality of steel filaments. Here, FIG. 2 is an explanatory view showing the relationship between the steel cord of the first steel wire reinforcing layer 11a and the steel cord of the second steel wire reinforcing layer 11b. As described above, the steel cord in which the steel filaments are twisted has irregularities due to the twists on the surface thereof. In the reinforcing layer 11 using such a steel cord, stress repeatedly concentrates between the convex portions on the surface of the steel cord, cracks are generated in the intermediate rubber layer 12, and it expands to cause peeling. When this convex part is sharper, stress concentrates and the intermediate rubber layer 12 tends to crack. When a pressure is applied to the high-pressure hose having the reinforcing layer 11 in which the steel cord is wound in a spiral shape, the inner layer is subjected to a greater stress on the steel cord, and the above problem becomes remarkable.

Therefore, the high-pressure hose 10 of the present invention is a steel filament which is the apex of the convex portion located at the outermost portion in the hose radial direction in the cross section perpendicular to the cord axis in all the steel cords 1a constituting the first steel wire reinforcing layer 11a. and the center point of 2a, and the same layer of the steel filaments 2a in the same steel cord, and the center point of the steel filaments arranged on both sides, the first convex angle theta ₁ which Naru signed and 108 ° or more . Here, in the illustrated example, a steel cord having a (1 × 5) structure is used, but in the case of a single-stranded steel cord having a (1 × n) structure, each steel filament constituting the steel cord is the same. Within one layer. Similarly, in the high-pressure hose 10 of the present invention, in all the steel cords 1b constituting the second steel wire reinforcing layer 11b, a steel filament that becomes a convex portion located at the innermost portion in the hose radial direction in a cross section perpendicular to the cord axis The second convex angle θ ₂ connecting the center point of 2b and the center points of the steel filaments arranged in the same layer of the same steel cord as the steel filament 2b on both sides is set to 108 ° or more. . In addition, n which shows the twist structure of a steel cord is arbitrary integers.

By satisfying the above relationship between the steel cord of the first steel wire reinforcing layer 11a and the steel cord of the second steel wire reinforcing layer 11b, that is, the convex portion of the first steel wire reinforcing layer 11a and the second steel wire Even if the distance between the steel cord 1a of the first steel wire reinforcing layer 11a and the steel cord 1b of the second steel wire reinforcing layer 11b is 1 mm or less by bringing the convex portion of the reinforcing layer 11b closer to an obtuse angle, the high-pressure hose 10 The steel wire reinforcing layers 11a and 11b can be prevented from being separated from each other, and impact durability can be ensured. Moreover, since the space | interval of the steel cord 1a of the 1st steel wire reinforcement layer 11a and the steel cord 1b of the 2nd steel wire reinforcement layer 11b can be 1 mm or less, the advantage that the hose outer diameter of the high pressure hose 10 does not become large. Is obtained. In order to obtain such an effect satisfactorily, the first convex angle θ ₁ and the second convex angle θ ₂ are preferably obtuse angles, and the first convex angle θ ₁ and the second convex angle θ ₂ are 129 °. The above is preferable, and more preferably 140 ° or more.

  In the high-pressure hose 10 of the present invention, the structure of the steel cord constituting each steel wire reinforcing layer 11 is not particularly limited as long as the above relationship is satisfied. For example, a steel cord having a 1 × n structure in which n (n ≧ 5) steel filaments are twisted around a cord central axis without a core, or m (m = 1 to 3) steel filaments A steel cord having a structure of (m + p) structure in which a sheath layer formed by twisting p (5 to 9) steel filaments is provided on a core formed by twisting or not twisting, and ( A steel cord having a (m + p + q) structure in which a sheath layer formed by twisting q (q = 10 to 13) steel filaments is further provided on a steel cord having a m + p) structure. A so-called compact structure in which all layers are twisted in the same direction and the same pitch may be used. In the high-pressure hose 10 of the present invention, for example, a steel formed by twisting p (5-9) steel filaments on a core formed without twisting m (m = 2 or 3) steel filaments. Since the cord has a flat cross-sectional shape, the number of steel cords driven into the steel wire reinforcing layer 11 can be reduced, and the steel wire reinforcing layer 11 itself can be thinned. It is preferable because of its superiority. In addition, m, p, and q which show the twist structure of a steel cord are arbitrary integers of the said range.

  In the high-pressure hose 10 of the present invention, a known steel filament constituting the steel cord can be used, but the wire diameter is preferably 0.12 to 0.40 mm. In this case, all the steel filaments may have the same wire diameter, or steel filaments having different wire diameters may be used. Further, the winding angle of the steel cord in the reinforcing layer 11 is preferably 50 to 60 °. When the wire diameter of the steel filament is less than 0.12 mm, the wire drawing productivity of the steel filament is deteriorated, and when it exceeds 0.40 mm, it is difficult to obtain the strength per cross-sectional area, and the bending rigidity proportional to the fourth power of the diameter is high. Become. Also, if the wrapping angle of the steel cord is less than 50 °, the change in hose diameter when the hose is pressurized increases, and if it exceeds 60 °, the change in hose length when the hose is pressurized increases. End up.

  As described above, the high-pressure hose 10 of the present invention has the advantage that the outer diameter of the hose can be reduced. From such a viewpoint, in the high-pressure hose 10 of the present invention, the distance between the steel cord 1a of the first steel wire reinforcing layer 11a and the steel cord 1b of the second steel wire reinforcing layer 11b is 1 mm or less. It is 6 mm or less, more preferably 0.4 mm or less, particularly preferably 0.25 mm or less, and further preferably 0.15 mm or less.

In the high-pressure hose 10 of the present invention, a reinforcing layer using a steel cord may be provided in addition to the first steel wire reinforcing layer 11a and the second steel wire reinforcing layer 11b. In this case, it is preferable that the same relationship is satisfied not only between the first steel wire reinforcing layer 11a and the second steel wire reinforcing layer 11b but also between reinforcing layers using other steel cords. That is, a cross section perpendicular to the cord axis of the steel cord constituting the Mth (M ≧ 2) steel wire reinforcing layer between the steel wire reinforcing layers 11 other than the first steel wire reinforcing layer 11a and the second steel wire reinforcing layer 11b. The M-th convex angle θ _n formed by connecting the center point of the steel filament located at the outermost part in the hose radial direction and the center points of the steel filaments located in the same layer and adjacent to the steel filament. The center point of the steel filament located at the innermost part in the hose radial direction in the cross section perpendicular to the cord axis of the steel cord constituting the (M + 1) th steel wire reinforcing layer is 108 ° or more, and within the same layer as this steel filament. Te, the Naru connects the center point of the steel filaments arranged on both sides, the (M + 1) convex angle theta _{(M + )} It is preferable that the 108 ° or more. Note that M is an arbitrary integer of 2 or more.

  In the high-pressure hose 10 of the present invention, the steel cord 1a of the first steel wire reinforcing layer 11a, which is the innermost steel wire reinforcing layer, and the second steel disposed outside the first steel wire reinforcing layer 11a in the hose radial direction. Since the steel cord 1b of the wire reinforcing layer 11b satisfies the above relationship, an impact is applied even if the thickness of the intermediate rubber layer 12a between the first steel wire reinforcing layer 11a and the second steel wire reinforcing layer 11b is 1 mm or less. Durability can be secured, and other specific structures and materials are not particularly limited.

  For example, in the high-pressure hose 10 of the present invention, the winding direction of the steel wire reinforcing layer 11 is not particularly limited, and in the illustrated example, the first layer from the inside is Z-winding, the second layer is S-winding, the third layer Is Z winding, and the fourth layer is S winding. The first layer is S winding, the second layer is Z winding, the third layer is S winding, the fourth layer is Z winding, It may be composed of four layers. Preferably it is 10 layers or less, More preferably, it is 8 layers or less. In the high-pressure hose 10 of the present invention, the winding direction of the steel cord of the steel wire reinforcing layer 11 of the N (N ≧ 1) layer, which is an arbitrary integer, and the steel wire reinforcing layer of the (N + 1) layer are not necessarily required. 11, the winding direction of the steel cord does not have to be different from each other, the winding direction of the steel cord of the N-th steel wire reinforcing layer 11 and the winding direction of the steel cord of the (N + 1) -th steel wire reinforcing layer 11 There may be a location where the same.

  The rubber used for the high-pressure hose 10 is not particularly limited, and the material of the inner rubber layer 13 can be appropriately selected based on the physical and chemical properties of the substance transported in the high-pressure hose 10. Specifically, for example, ethylene-propylene copolymer rubber (EPM), ethylene-propylene-diene terpolymer rubber (EPDM), acrylic rubber (ACM), ethylene acrylate rubber (AEM), chloroprene rubber (CR ), Chlorosulfonated polyethylene rubber, hydrin rubber, styrene-butadiene copolymer rubber (SBR), acrylonitrile-butadiene copolymer rubber (NBR), isobutylene-isoprene copolymer rubber (butyl rubber, IIR), natural rubber (NR), isoprene Examples thereof include rubber (IR), butadiene rubber (BR), urethane rubber, silicone rubber, fluorine rubber, ethylene-vinyl acetate copolymer (EVA), and hydrogenated NBR. These rubber components may be used individually by 1 type, or may be used as arbitrary blends of 2 or more types.

  Among the above rubber components, from the viewpoint of oil resistance, acrylic rubber (ACM), ethylene acrylate rubber (AEM), chloroprene rubber (CR), chlorosulfonated polyethylene rubber, hydrin rubber, acrylonitrile-butadiene copolymer rubber (NBR), hydrogen NBR, silicone rubber, and fluorine rubber are preferable.

  The rubber composition for the inner rubber layer 13 uses known rubber compounding chemicals and rubber fillers generally used in the rubber industry in consideration of material strength, durability, extrudability and the like. can do. Examples of such chemicals and fillers include inorganic fillers such as carbon black, silica, calcium carbonate, talc and clay; plasticizers, softeners; vulcanizing agents such as sulfur and peroxides; zinc oxide, stearin Vulcanization aids such as acids; vulcanization accelerators such as dibenzothiazyl disulfide, N-cyclohexyl-2-benzothiazyl-sulfenamide, N-oxydiethylene-benzothiazyl-sulfenamide; antioxidants, ozone deterioration inhibitors And the like. These compounding chemicals and fillers may be used alone or in combination of two or more.

  The thickness of the inner rubber layer 13 varies depending on the type of material constituting the inner rubber layer 12, but is in the range of 1 to 10 mm, preferably in the range of 1 to 6 mm. Moreover, although the internal diameter of a high pressure hose is selected according to the objective, generally it is preferable that it is the range of 3 mm-200 mm.

  Further, the outer rubber layer 14 can be made of, for example, a thermoplastic resin as in the conventional high-pressure hose, and may be made of various rubbers similar to the inner rubber layer 12. By providing the outer rubber layer 13, the steel cord constituting the reinforcing layer 11 can be protected to prevent the reinforcing layer 11 from being damaged, and the appearance is also preferable. The general thickness of the outer rubber layer 13 is in the range of 1 mm to 20 mm.

  Further, the intermediate rubber layer 12 can be formed of various rubbers similar to the inner rubber layer 13.

  The high-pressure hose of the present invention can be manufactured in accordance with a conventional method, and in particular, a high-pressure hose used for transporting various high-pressure fluids, and a high-pressure hose used for pumping hydraulic oil of a hydraulic pump to an operating part. Useful as.

Hereinafter, the present invention will be described in more detail with reference to examples.
<Examples 1-12 and Comparative Examples 1-3>
Steel cords having the structures shown in the table were prepared using steel filaments having the wire diameters shown in Tables 1 to 3 below. The obtained steel cord was used as a reinforcing material for the first steel wire reinforcing layer and the second steel wire reinforcing layer to produce a high-pressure hose having the structure shown in FIG. The winding direction of the steel cord was Z winding for the first layer, S winding for the second layer, Z winding for the third layer, S winding for the fourth layer, and the winding angle was 54.7 °. In addition, the intermediate rubber layer was arranged so that the distance between the steel cord of the first reinforcing layer and the steel cord of the second reinforcing layer was as shown in the same table. For Examples 7 to 8, the long diameter in the cross-sectional shape of the cross section perpendicular to the cord axis of the steel cord is arranged along the circumferential direction in the cross section perpendicular to the hose axial direction of the hose, and the high pressure hose is arranged. Produced.

<Impact durability>
An impact pressure test in accordance with JIS K6330-8 was performed, and the number of pressure tests performed until each high-pressure hose burst was recorded. Tables 1 to 3 show the number of pressure tests for each high-pressure hose.

※第１補強層のスチールコードと第２補強層のスチールコードとの間隔

* Distance between the steel cord of the first reinforcement layer and the steel cord of the second reinforcement layer

  Tables 1 to 3 show that the high-pressure hose of the present invention has excellent impact durability.

1 Steel cord 2 Steel filament 10 High pressure hose 11 Reinforcement layer (Steel wire reinforcement layer)
12 Intermediate rubber layer 13 Inner rubber layer 14 Outer rubber layer

Claims (4)

In a high pressure hose having a structure in which a plurality of steel wire reinforcing layers having a spiral structure are laminated,
The first steel wire reinforcing layer, which is at least the innermost steel wire reinforcing layer, and the second steel wire reinforcing layer provided outside the first steel wire reinforcing layer in the hose radial direction twist a plurality of steel filaments. It is a steel cord reinforcement layer that includes steel cords that are combined,
In all the steel cords of the first steel wire reinforcing layer, the center point of the steel filament located at the outermost portion in the hose radial direction in the cross section perpendicular to the cord axis and the same layer as that of the steel filament are arranged on both sides. The first convex angle θ ₁ formed by connecting the center point of the steel filament is 108 ° or more,
In all the steel cords of the second steel wire reinforcing layer, the center point of the steel filament located at the innermost part in the hose radial direction in the cross section perpendicular to the cord axis and the same layer as that of the steel filament are arranged on both sides. The second convex angle θ ₂ connecting the center point of the steel filament is 108 ° or more,
A high-pressure hose characterized in that a distance between a steel cord of the first steel wire reinforcing layer and a steel cord of the second steel wire reinforcing layer is 1 mm or less. The high-pressure hose according to claim 1, wherein the first convex angle θ ₁ and the second convex angle θ ₂ are 129 ° or more.   The high-pressure hose according to claim 1 or 2, wherein a distance between a steel cord of the first steel wire reinforcing layer and a steel cord of the second steel wire reinforcing layer is 0.6 mm or less.   The high-pressure hose according to any one of claims 1 to 3, wherein a cross section of the steel cord perpendicular to the cord axis direction is flat.

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