JP6892292B2 - High pressure hose - Google Patents

Description

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

Flexible high-pressure hoses used for power steering hoses of construction machines, machine tools, automobiles, measuring instruments, etc. are generally provided with an inner rubber layer and a plurality of reinforcing layers on the outer periphery thereof. Steel filaments and fibers such as nylon and polyester are usually used as reinforcing materials for high-pressure hoses provided with this reinforcing layer. For example, in the case of a high-pressure hose having a four-layer structure, right-handed winding and left-handed winding are used. It is wrapped so that it alternates with the attachment.

Patent Documents 1 to 6 are mentioned as techniques for improving such a high-pressure hose, and in these Patent Documents 1 to 6, a steel wire rod is used as a reinforcing material of a reinforcing layer. It is also known that an intermediate rubber is arranged between the reinforcing layers in the high pressure hose. For example, Patent Document 7 states that the gas permeation resistance of the barrier layer made of a resin film of polyvinyl alcohol is not lowered, the gas permeation resistance thereof can be sufficiently exhibited, and the gas permeation is satisfactorily suppressed. A low gas permeable hose that can be used has been proposed. Further, Patent Document 8 proposes a high-pressure hose that is flexible and has low flexural rigidity, in which a decrease in internal pressure resistance and impact pressure resistance due to high temperature is particularly small by providing a specific intermediate layer between the layers for reinforcing the multi-layer spiral filament. ..

Japanese Unexamined Patent Publication No. 2012-036927 Japanese Unexamined Patent Publication No. 2008-002637 Japanese Unexamined Patent Publication No. 2001-041361 Jikkenhei 01-104495 Japanese Unexamined Patent Publication No. 09-137392 Japanese Unexamined Patent Publication No. 08-027686 Japanese Unexamined Patent Publication No. 2008-248995 Japanese Unexamined Patent Publication No. 60-143286

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

Conventionally, steel cords that require the man-hours of twisting steel filaments are not generally used because it is not required to achieve both strength and flexibility as much as tires for reinforcement of high-pressure hoses. However, in order to impart high strength and flexibility to high pressure hoses used at higher pressures, there is a limit to using single wire steel filaments, and steel filaments such as those used in high pressure hoses to reinforce tires. It is conceivable to apply a steel cord made by twisting. However, a high-pressure hose using a steel cord in which steel filaments are twisted as a reinforcing material has a new problem that the impact durability may not be sufficiently improved.

Therefore, an object of the present invention is to provide a high-pressure hose having excellent impact durability while using a steel cord in which a steel filament is twisted as a reinforcing material.

As a result of diligent studies to solve the above problems, the present inventors have obtained the following findings. That is, as a result of observing the fractured form of the high-pressure hose, it was found that the layers of the steel cord reinforcing layer were peeled off. In particular, the peeling between the first layer and the second layer 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 is intermediate. The starting point was inside the rubber. Such peeling was not seen when a normal steel filament was used as a single wire. As a result of further diligent studies by the present inventors based on such findings, since the steel cord obtained by twisting the steel filaments has irregularities due to the twists on the surface thereof, each steel cord is provided between the steel cord reinforcing layers. Repeated stress is concentrated between the convex parts of each other, causing cracks in the rubber, which expands and leads to peeling. Then, it was found that when the convex portion is sharper, stress is concentrated between the convex portions and cracks are likely to occur in the intermediate rubber layer. Therefore, the present inventors have found that the above problems 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 steel wire reinforcing layer having a spiral structure is laminated in a plurality of layers via an intermediate rubber layer.
At least the first steel wire reinforcing layer, which is the innermost steel wire reinforcing layer, and the second steel wire reinforcing layer provided on the outer side of the first steel wire reinforcing layer in the hose radial direction twist a plurality of steel filaments. It is a steel cord reinforcement layer including a combined steel cord,
The intermediate rubber layer is an ethylene-propylene copolymer rubber, an ethylene-propylene-diene ternary copolymer rubber, an acrylic rubber, an ethyleneacryllate rubber, a chloroprene rubber, a chlorosulfonated polyethylene rubber, a hydrin rubber, a styrene-butadiene copolymer rubber. , Acrylonitrile-butadiene copolymer rubber, isobutylene-isoprene copolymer rubber, natural rubber, isoprene rubber, butadiene rubber, urethane rubber, silicone rubber, fluorine rubber, ethylene-vinyl acetate copolymer and hydride acrylonitrile-butadiene Formed from a blend of one or more of the copolymerized rubbers,
In all the steel cords of the first steel wire reinforcing layer, the center point of the steel filament located at the outermost side in the hose radial direction in the cross section perpendicular to the cord axis, and within the same layer as the steel filament and are arranged on both sides. _{The first convex angle θ 1} 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 position in the radial direction of the hose in the cross section perpendicular to the cord axis, and within the same layer as the steel filament and 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, and the steel wire rod is a broad definition that combines the steel filament and the steel cord. To 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. Further, in the high-pressure hose of the present invention, the distance between the steel cord of the first steel wire rod reinforcing layer and the steel cord of the second steel wire rod reinforcing layer is preferably 0.6 mm or less. Further, in the high pressure hose of the present invention, it is preferable that the cross section of the steel cord perpendicular to the cord axis direction is flat.

According to the present invention, it is possible to provide a high-pressure hose having excellent impact durability while using a steel cord in which a steel filament is twisted as a 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, it is possible to alleviate the distortion in the rubber between the reinforcing layers of each steel wire, and the first The distance between the steel cord of the 1 reinforcing layer and the steel cord of the 2nd reinforcing layer can be narrowed. 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 sectional drawing of the high pressure hose which concerns on one preferred embodiment of this invention. It is explanatory drawing which shows the relationship between the steel cord of the 1st steel wire rod reinforcing layer, and the steel cord of the 2nd steel wire rod reinforcing 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 layers of a steel wire reinforcing layer 11 having a spiral structure (hereinafter, also simply referred to as “reinforcing layer 11”) are laminated, and in the illustrated example, the hose is reinforced. The layers 11 are 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 rod reinforcing layer, and may have, for example, a reinforcing layer using a cord other than the steel cord such as an organic fiber cord. For example, an organic fiber reinforcing layer such as vinylon, nylon, or PET may be provided inside the steel wire reinforcing layer. The high-pressure hose 10 shown has a tubular inner rubber layer 13 formed in the innermost layer and a tubular outer rubber layer 14 formed in the outermost layer, and four layers are formed between the inner rubber layer 13 and the outer rubber layer 14. The steel wire rod reinforcing layer 11 and the three intermediate rubber layers 12 may be arranged alternately.

In the high-pressure hose 10 of the present invention, at least the first steel wire reinforcing layer 11a, which is the innermost steel wire reinforcing layer, and the second steel wire reinforcing layer 11a provided on the outer side in the hose radial direction of the first steel wire reinforcing layer 11a. The layer 11b is a steel cord reinforcing layer including a steel cord formed by twisting a plurality of steel filaments. Here, FIG. 2 shows an explanatory diagram showing the relationship between the steel cord of the first steel wire rod reinforcing layer 11a and the steel cord of the second steel wire rod reinforcing layer 11b. As described above, the steel cord obtained by twisting the steel filaments has irregularities due to the twists on the surface thereof. In the reinforcing layer 11 using such a steel cord, repeated stress is concentrated between the convex portions on the surface of the steel cord to cause cracks in the intermediate rubber layer 12, which expands and leads to peeling. When the convex portion is sharper, stress is concentrated and cracks are likely to occur in the intermediate rubber layer 12. Then, when pressure is applied to a high-pressure hose having a reinforcing layer 11 in which the steel cord is wound in a spiral shape, a larger stress is applied to the steel cord in the inner layer, and the above problem becomes remarkable.

Therefore, the high-pressure hose 10 of the present invention is a steel filament that is located at the outermost part in the hose radial direction in the cross section perpendicular to the cord axis and is the apex of the convex portion in all the steel cords 1a constituting the first steel wire rod reinforcing layer 11a. _{The first convex angle θ 1} formed by connecting the center point of 2a and the center points of the steel filaments arranged on both sides in the same layer of the same steel cord as the steel filament 2a is 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-twisted steel cord having a (1 × n) structure, the steel filaments constituting the steel cord are the same. It will be one layer inside. Similarly, in the high-pressure hose 10 of the present invention, in all the steel cords 1b constituting the second steel wire rod reinforcing layer 11b, a steel filament having a convex portion located at the innermost part in the hose radial direction in a cross section perpendicular to the cord axis. _{The second convex angle θ 2} formed by connecting the center point of 2b and the center points of the steel filaments arranged on both sides in the same layer of the same steel cord as the steel filament 2b is set to 108 ° or more. .. Note that n indicating the twisted structure of the steel cord is an arbitrary integer.

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. By bringing the convex portion of the reinforcing layer 11b close to an blunt angle, 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, the high-pressure hose 10 It is possible to prevent peeling between the layers of the steel wire rod reinforcing layers 11a and 11b, and to ensure impact durability. Further, since 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 can be set to 1 mm or less, there is an advantage that the hose outer diameter of the high pressure hose 10 does not increase. 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 rod 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 the central axis of the cord without a core, or m (m = 1-3) steel filaments. A steel cord having a (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 further ( An example of the steel cord having a structure of (m + p + q) is a steel cord having a structure of (m + p + q) in which a sheath layer formed by twisting q (q = 10 to 13) steel filaments is further provided on the steel cord having a structure of m + p). A so-called compact structure in which all layers are twisted in the same direction and at the same pitch may be used. In the high-pressure hose 10 of the present invention, for example, steel formed by twisting p (5 to 9) steel filaments to 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, so that the weight and cost can be reduced. It is preferable because it is excellent in terms of surface. Note that m, p, and q indicating the twisted structure of the steel cord are arbitrary integers in the above range.

In the high-pressure hose 10 of the present invention, known steel filaments can be used as the steel filament constituting the steel cord, but the wire diameter is preferably 0.12 to 0.40 mm. In this case, the wire diameters of all the steel filaments may be the same, 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 °. If the wire diameter of the steel filament is less than 0.12 mm, the wire drawing productivity of the steel filament deteriorates, and if it exceeds 0.40 mm, it is difficult to obtain the strength per cross-sectional area, and the flexural rigidity proportional to the fourth power of the diameter is high. Become. In addition, when the winding angle of the steel cord is less than 50 °, the change in hose diameter when pressure is applied to the hose becomes large, and when it exceeds 60 °, the change in hose length when pressure is applied to the hose becomes large. It ends up.

As described above, the high pressure hose 10 of the present invention has an advantage that the outer diameter of the hose can be reduced. From this point of view, 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 set to 1 mm or less, but preferably 0. It is 6 mm or less, more preferably 0.4 mm or less, particularly preferably 0.25 mm or less, still more 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 rod reinforcing layer 11a and the second steel wire rod reinforcing layer 11b. In this case, it is preferable that not only the relationship between the first steel wire reinforcing layer 11a and the second steel wire reinforcing layer 11b but also the reinforcing layers using other steel cords satisfy the same relationship. That is, a cross section perpendicular to the cord axis of the steel cord constituting the M (M ≧ 2) steel wire reinforcing layer 11 between the first steel wire reinforcing layer 11a and the steel wire reinforcing layer 11 other than the second steel wire reinforcing layer 11b. _{The Mth convex angle θ n} formed by connecting the center point of the steel filament located on the outermost side in the radial direction of the hose and the center points of the steel filaments arranged on both sides in the same layer as the steel filament. The center point of the steel filament located at the innermost position in the radial direction of the hose in the cross section perpendicular to the cord axis of the steel cord forming the first (M + 1) steel wire reinforcing layer at 108 ° or more, and within the same layer as this steel filament. Therefore, it is preferable that the _{third (M + 1) convex angle θ (M + 1)} connecting the center points of the steel filaments arranged on both sides is 108 ° or more. In addition, 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 arranged outside the first steel wire reinforcing layer 11a in the hose radial direction. By satisfying the above relationship with the steel cord 1b of the wire rod reinforcing layer 11b, even if the thickness of the intermediate rubber layer 12a between the first steel wire rod reinforcing layer 11a and the second steel wire rod reinforcing layer 11b is 1 mm or less, the impact is impacted. Durability can be ensured, and other specific structures, materials, etc. 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. In the illustrated example, the first layer from the inside is Z-wound, the second layer is S-wound, and the third layer. Is composed of 4 layers, the 4th layer is S winding, the 1st layer is S winding, the 2nd layer is Z winding, the 3rd layer is S winding, and the 4th layer is Z winding. It may be composed of four layers. It is preferably 10 layers or less, more preferably 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 and the steel wire reinforcing layer of the (N + 1) layer are necessarily arbitrary integers. The winding direction of the steel cord of the 11th layer does not have to be different from each other, and the winding direction of the steel cord of the steel wire reinforcing layer 11 of the Nth layer and the winding direction of the steel cord of the steel wire reinforcing layer 11 of the (N + 1) layer. There may be places where are the same.

The rubber used for the high-pressure hose 10 is also 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 ternary copolymer rubber (EPDM), acrylic rubber (ACM), ethylene acrylic 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-based rubber, silicone-based rubber, fluorine-based rubber, ethylene-vinyl acetate copolymer (EVA), and hydride NBR. These rubber components may be used alone or as an arbitrary blend of two or more.

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

Further, in the rubber composition for the inner rubber layer 13, in consideration of material strength, durability, extrusion moldability, etc., known rubber compounding chemicals and rubber fillers generally used in the rubber industry are used. can do. Examples of such compounding chemicals and fillers include inorganic fillers such as carbon black, silica, calcium carbonate, talc and clay; plasticizers and softeners; vulcanizers such as sulfur and peroxide; zinc oxide and stearer. Vulcanization aids such as acids; vulcanization accelerators such as dibenzothiazyl disulfide, N-cyclohexyl-2-benzothiadyl-sulfenamide, N-oxydiethylene-benzothiazyl-sulfenamide; antioxidants, ozone deterioration inhibitors Additives such as. 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. The inner diameter of the high-pressure hose is selected according to the purpose, but is generally preferably in the range of 3 mm to 200 mm.

Further, the outer rubber layer 14 may be made of, for example, a thermoplastic resin or the like, like 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 wall 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 according to 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 a working portion. It is useful as.

Hereinafter, the present invention will be described in more detail with reference to examples.
<Examples 1 to 12 and Comparative Examples 1 to 3>
Using the steel filaments having the wire diameters shown in Tables 1 to 3 below, steel cords having the structures shown in the same table were produced. The obtained steel cord was used as a reinforcing material for the first steel wire rod reinforcing layer and the second steel wire rod reinforcing layer, and a high-pressure hose having the structure shown in FIG. 1 was produced. 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, and S winding for the fourth layer, and the winding angle was 54.7 °. Further, 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. In Examples 7 to 8, the major axis in the cross-sectional shape perpendicular to the cord axis of the steel cord is arranged along the circumferential direction in the cross section perpendicular to the hose axis direction of the hose, and the high-pressure hose is placed. Made.

<Impact durability>
Impact pressure tests according to JIS K6330-8 were performed, and the number of pressure tests performed until each high pressure hose ruptured 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 reinforcing layer and the steel cord of the second reinforcing layer

From Tables 1 to 3, it can be seen that the high pressure hose of the present invention has excellent impact durability.

1 Steel cord 2 Steel filament 10 High-pressure hose 11 Reinforcing layer (steel wire reinforcing 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 steel wire reinforcing layer having a spiral structure is laminated in a plurality of layers via an intermediate rubber layer.
At least the first steel wire reinforcing layer, which is the innermost steel wire reinforcing layer, and the second steel wire reinforcing layer provided on the outer side of the first steel wire reinforcing layer in the hose radial direction twist a plurality of steel filaments. It is a steel cord reinforcement layer including a combined steel cord,
The intermediate rubber layer is an ethylene-propylene copolymer rubber, an ethylene-propylene-diene ternary copolymer rubber, an acrylic rubber, an ethylene acrylate rubber, a chloroprene rubber, a chlorosulfonated polyethylene rubber, a hydrin rubber, a styrene-butadiene copolymer rubber, and an acrylonitrile. -Butadiene copolymer rubber, isobutylene-isoprene copolymer rubber, natural rubber, isoprene rubber, butadiene rubber, urethane rubber, silicone rubber, fluorine rubber, ethylene-vinyl acetate copolymer and hydride acrylonitrile-butadiene copolymer Formed from one or more blends of rubber,
In all the steel cords of the first steel wire reinforcing layer, the center point of the steel filament located at the outermost side in the hose radial direction in the cross section perpendicular to the cord axis, and within the same layer as the steel filament and are arranged on both sides. _{The first convex angle θ 1} 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 position in the radial direction of the hose in the cross section perpendicular to the cord axis, and within the same layer as the steel filament and 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 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. 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 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 0.6 mm or less. The high-pressure hose according to any one of claims 1 to 3, wherein the cross section of the steel cord perpendicular to the cord axis direction is flat.

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