Resin-reinforced rubber hose

Abstract

We provide rubber hoses with a resin-reinforced core. [Solution] A rubber hose for fluid transport is provided, comprising a spiral reinforcing core 4 between an inner rubber layer 1 and an outer rubber layer 6, characterized in that the reinforcing core is made of a resin material. This makes it possible to reduce the overall weight of the rubber hose, contributing to improved handling, and the material composition is simplified, making it easier to select disposal methods other than landfill (such as thermal recycling) after use, rather than being limited to landfill disposal, thus contributing to a reduction in environmental burden. Conventional rubber hoses equipped with a spiral metal reinforcing core have been heavy due to the high density of the reinforcing core, which reduces handling at construction sites, etc., and also presents challenges in terms of recyclability as material separation is difficult after use.

Description

Technical Field

[0001] The present invention relates to a rubber hose for fluid transportation, and particularly to a rubber hose provided with a spiral reinforcing core between an inner rubber layer and an outer rubber layer.

Background Art

[0002] Conventionally, in applications where negative pressure resistance is required among rubber hoses for fluid transportation, a structure in which a spiral metal reinforcing core (such as a hard steel wire) is arranged between an inner rubber layer and an outer rubber layer to ensure cross-sectional shape retention and negative pressure resistance has been widely adopted. This makes it possible to suppress flattening and buckling of the cross-section caused by external pressure. Patent Document 1 discloses a rubber hose provided with a similar spiral metal reinforcing core.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a rubber hose used in applications where negative pressure resistance is required and provided with a spiral reinforcing core, in the conventional configuration using a metal reinforcing core, there is a problem that the rubber hose becomes heavier due to the high density of the reinforcing core, and the handling property at a construction site or the like deteriorates. Furthermore, since it has a composite structure of rubber and metal, material separation after use becomes difficult, and there are also problems from the perspective of environmental load, such as the disposal method being likely to be biased towards landfill disposal. In order to solve these problems, the present invention aims to contribute to reducing the environmental load by reducing the weight of the rubber hose and making it easier to select a disposal method other than landfill (such as thermal recycling) in disposal after use.

Means for Solving the Problems

[0005] To solve the above problems, the present invention provides a rubber hose for fluid transport, comprising a spiral reinforcing core between an inner rubber layer and an outer rubber layer, characterized in that the reinforcing core is made of a resin material. Furthermore, it is preferable that the density of the resin material constituting the reinforcing core is 1.6 or less. Furthermore, the reinforcing core is made of a thermoplastic resin material containing at least one of polyester, nylon, polyethylene, and polypropylene. Furthermore, the cross-sectional shape of the reinforcing core is either round, flattened, or polygonal. [Effects of the Invention]

[0006] According to this invention, in a rubber hose for fluid transport having a spiral reinforcing core between an inner rubber layer and an outer rubber layer, the reinforcing core is made of a resin material. As a result, the overall weight of the rubber hose can be reduced compared to conventional rubber hoses using a metal reinforcing core, which contributes to improved handling. Furthermore, because the reinforcing core does not use metal materials, the material composition is simpler compared to composites of rubber and metal. This makes it easier to choose disposal methods other than landfill (such as thermal recycling) after use, rather than being limited to landfill disposal, thus contributing to a reduction in environmental impact. Specifically, by reducing the density of the reinforcing core to 1.6 or less, the weight of the reinforcing core can be reduced to approximately one-fifth or less compared to conventional metal materials (for example, hard steel wire with a density of approximately 7.8), contributing to the overall weight reduction of the rubber hose. Furthermore, the configurations according to claims 3 and 4 make it possible to select the cross-sectional shape of the resin material and the reinforcing core according to the application, thereby ensuring design flexibility without compromising the objectives of the present invention, which are weight reduction and improved disposability. [Brief explanation of the drawing]

[0007] [Figure 1] This is a cross-sectional structural diagram showing one embodiment of the rubber hose according to the present invention. [Figure 2] This is an enlarged view of Figure 1. [Modes for carrying out the invention]

[0008] The rubber hose shown in Figure 1 is the main body of a rubber hose for transporting fluids, and is composed of, in order from the inner side, an inner rubber layer 1, a reinforcing layer 2, an intermediate rubber layer 3, a reinforcing core 4, a reinforcing layer 5, and an outer rubber layer 6. Note that Figure 1 is a schematic diagram to facilitate understanding of the structure, and the thickness and ratio of each layer do not limit the actual product configuration.

[0009] A distinctive feature of this invention lies in the reinforcing core 4, which is positioned between the inner rubber layer 1 and the outer rubber layer 6. In this embodiment, the reinforcing core 4 is arranged spirally along the longitudinal direction of the rubber hose to suppress the collapse of the rubber hose during fluid suction, etc.

[0010] In this embodiment, the reinforcing core 4 is made of a resin reinforcing core formed from a resin material into a linear shape, rather than a metal material such as hard steel wire that has been widely used in the past. By making the reinforcing core 4 from resin in this way, it becomes possible to use a material with a lower density compared to metal materials, thereby reducing the overall weight of the rubber hose.

[0011] The resin material used for the reinforcing core 4 is composed of a thermoplastic resin material containing at least one of polyester, nylon, polyethylene, or polypropylene. Depending on the application and required properties, engineering plastics such as polyacetal (POM), polycarbonate (PC), and polybutylene terephthalate (PBT) may also be used. Since these resin materials generally have a density of 1.6 or less in their unfilled grades, they offer excellent lightweight properties, and properties such as flexibility, abrasion resistance, chemical resistance, and heat resistance can be selectively imparted depending on the application.

[0012] Furthermore, the cross-sectional shape of the reinforcing core 4 may be round, flat, or polygonal. For example, a round cross-section allows for a configuration that takes manufacturability into consideration, while a flat cross-section allows for a configuration that ensures a large contact area with the rubber layer. Moreover, a polygonal cross-section allows for the selection of a cross-sectional shape according to the application and manufacturing conditions, thereby increasing the design flexibility of the reinforcing core 4.

[0013] The reinforcing core 4 can be arranged spirally in one or more strands, depending on the application, inner diameter, wall thickness, etc., of the rubber hose. The spiral winding direction can be either S-winding or Z-winding, and a spiral configuration with multiple directions may be used as needed.

[0014] The arrangement pitch (spacing of the spirals) of the reinforcing core 4 can be arbitrarily set according to the negative pressure resistance and flexibility required for the rubber hose. For example, compared to conventional products using metal reinforcing cores, by increasing the diameter of the resin reinforcing core and further reducing the arrangement pitch (for example, to about two-thirds the pitch of conventional products), it is possible to increase the rigidity in the cross-sectional direction and improve negative pressure resistance while maintaining lightness. On the other hand, it is also possible to use a wider pitch depending on the application, and this invention is not limited to a specific pitch.

[0015] The rubber hose using the resin reinforcing core according to this invention can reduce the overall weight of the rubber hose while maintaining negative pressure resistance through its spiral reinforcing structure, compared to conventional rubber hoses of the same inner diameter and length that use metal reinforcing cores such as hard steel wire. Specifically, the spirally arranged reinforcing cores suppress the flattening (buckling) of the hose cross-section caused by external pressure under negative pressure.

[0016] The placement of the reinforcing core 4 is not limited to the space between the reinforcing layers 2 and 5 and the intermediate rubber layer 3. Various configurations can be adopted, such as placing it between the intermediate rubber layer 3 and the outer rubber layer 6, placing multiple reinforcing cores 4 between different rubber layers, or combining these arrangements. In addition, the arrangement position, number, interval, and arrangement mode of the reinforcing core 4 can be appropriately set according to the use of the rubber hose, its inner diameter, wall thickness, required negative pressure resistance, flexibility, etc., and the present invention is not limited to a specific arrangement configuration.

[0017] Note that the rubber hose according to the present invention is not necessarily limited to a configuration that includes all of the reinforcing layers 2, 5 or the intermediate rubber layer 3 on the premise that it includes an inner rubber layer and an outer rubber layer, and a configuration in which some of these layers are omitted may be adopted according to the use and required characteristics.

[0018] The present invention is not limited to the above-described embodiment, and the type of rubber material, the thickness of each layer, the combination of layer configurations, etc. can be appropriately changed without departing from the gist of the present invention.

[0019] The rubber hose according to the present invention is not limited to applications with negative pressure resistance, and is applicable to various rubber hoses for fluid transportation.

Example

[0020] As an example, a rubber hose was manufactured in which a round resin reinforcing core made of polyester was spirally arranged between the inner rubber layer and the outer rubber layer. The reinforcing core was made of a polyester resin with a density of about 1.4, and no metal material such as a hard steel wire was used. In addition, the rubber hose according to the present example was about 20% lighter than a rubber hose of the same inner diameter and the same length using a conventional metal reinforcing core. As a result, an improvement in handling performance at a construction site or the like can be expected. Furthermore, the negative pressure resistance was -0.1 MPa, which was equivalent to that of a rubber hose using a metal reinforcing core having the above-described configuration. Note that the present example shows an example of the present invention, and the resin material and cross-sectional shape of the reinforcing core can be appropriately changed within the scope described in claims 2, 3, and 4.

Explanation of Reference Numerals

[0021] 1: Inner rubber layer 2: Reinforcing layer 3: Intermediate rubber layer 4: Reinforcement core 5: Reinforcement layer 6: Outer rubber layer

Claims

1. A rubber hose for fluid transport, comprising a spiral reinforcing core between an inner rubber layer and an outer rubber layer, characterized in that the reinforcing core is made of a resin material.

2. In the rubber hose according to claim 1, A rubber hose characterized in that the density of the resin material constituting the reinforcing core is 1.6 or less.

3. In the rubber hose according to claim 1 or 2, The rubber hose is characterized in that the reinforcing core is made of a thermoplastic resin material containing at least one of polyester, nylon, polyethylene, and polypropylene.

4. In the rubber hose according to claim 1 or 2, A rubber hose characterized in that the cross-sectional shape of the reinforcing core is round, flat, or polygonal.

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