JPH06249371A - High pressure hose for hydraulic pressure - Google Patents

Abstract

PURPOSE:To decrease the thickness of an inner surface layer, to reduce the weight of a hose body, to reduce diameter, to set a minimum bending radius to a low value through reduction of the outside diameter of a reinforcing layer, and to effectively prevent formation of a pin hole in an inner surface layer. CONSTITUTION:A hose body 1 comprises an inner surface layer 2 comprising double structure of an inner cylinder 2a and an outer cylinder 2b; and an outer surface layer 4 with which the outer cylinder 2b is covered through a reinforcing layer 3 formed of a steel wire (a piano wire). An adhesive layer 5 is formed between the inner and outer cylinders 2a and 2b. The inner cylinder 2a of the inner surface layer 2 is formed of a material having a tensile strength or rigidity higher than those of a material of which the outer cylinder 2b is formed, and of a material having higher internal fluid resistance and heat resistance compared with those of a material of which the outer cylinder 2b is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-pressure hydraulic hose used in a high-pressure hydraulic piping system for construction machinery, industrial machinery, etc., and more specifically, it is lightweight and can be reduced in diameter and has a minimum bending radius. The present invention relates to a high pressure hose for hydraulic pressure that can reduce the pressure.

[0002]

2. Description of the Related Art Conventionally, a high-pressure hydraulic hose used in a high-pressure hydraulic piping system for construction machinery, industrial machinery, etc. has a steel wire or fiber reinforcing layer interposed between an inner rubber layer and an outer rubber layer. Things are common. The above-mentioned hydraulic high-pressure hose is considered to be preferable as the hydraulic piping system is designed so that it is light in weight, small in diameter, and smaller in minimum bending radius.

[0003]

However, in the case of the above-mentioned conventional high-pressure hydraulic hose mainly made of rubber material, in order to reduce the weight and the diameter, the thickness of the inner rubber layer is made thin. Then, pinholes are likely to occur, and the life of the inner rubber against heat is proportional to the wall thickness. Therefore, if the wall thickness is made thinner, the weight is reduced, and the diameter is reduced, the life is shortened accordingly. There is a limit to reducing the thickness of the inner rubber layer in order to reduce the weight and diameter of
Even when designing a hydraulic piping system, the target weight reduction,
There is a problem that it is difficult to reduce the diameter.

The present invention has been devised in view of the above-mentioned conventional problems, and enables thinning of the inner surface layer to reduce the weight and diameter of the hose body and to increase the outer diameter of the reinforcing layer. It is an object of the present invention to provide a high-pressure hose for hydraulic pressure in which the minimum bending radius can be set to a small value and the occurrence of pinholes in the inner surface layer can be effectively prevented.

[0005]

In order to achieve the above object, the present invention has an inner surface layer composed of an inner cylinder and an outer cylinder made of a synthetic resin material alone, a rubber material alone or a mixture of a synthetic resin material and a rubber material. The gist of the invention is that the reinforcing layer is made of steel wire and the outer surface layer is made of a synthetic resin material alone, a rubber material alone, or a mixture of a synthetic resin material and a rubber material.

[0006]

The present invention is constructed as described above, and the inner surface layer has a double structure of an inner cylinder and an outer cylinder, and the inner cylinder uses a material having a higher tensile strength or hardness than the outer cylinder. Along with
By using a material that has better resistance to internal fluids and heat than the outer cylinder, pinholes can be effectively prevented even if the inner surface layer is thin, and the inner surface layer can be made thinner by making the inner surface layer thinner. Since the outer diameter is also small, the amount of reinforcing material used in the reinforcing layer can be small, and the outer diameter of the reinforcing layer can be reduced by using steel wire. The minimum bending radius can be set small.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a partially cutaway perspective view of a high-pressure hydraulic hose embodying the present invention.
Is an inner surface layer 2 having a double structure of an inner cylinder 2a and an outer cylinder 2b.
And an outer surface layer 4 covered on the outer cylinder 2b through a reinforcing layer 3 made of steel wire (piano wire), and an adhesive layer 5 is provided between the inner cylinder 2a and the outer cylinder 2b. Intervened.

The inner cylinder 2a of the inner surface layer 2 is made of a material having higher tensile strength or hardness than the outer cylinder 2b, and is made of a material having better internal fluid resistance and heat resistance than the outer cylinder 2b. use. Specifically, the inner cylinder 2a of the inner surface layer 2 may be anything as long as it has liquid resistance to the internal fluid, provided that it is harder and has better heat resistance than the material of the outer cylinder. . For example, when a resin material is used, nylon 6, nylon 66, nylon 6-66 copolymer, nylon 11, nylon 12, polyester, etc. are used, and when an alloy (mixture) of resin and rubber is used, , N1
When N1, N6, alloy of polyolefin, N6, N66, polyolefin, etc. are used and rubber material is used, NBR, CR, CSM, H-NBR (hydrogenated NB
R), EPDM, IIR, Cl-IIR, CPE, SBR
Etc. are used.

The material of the outer cylinder 2b of the inner surface layer 2 is NBR, SBR, IIR, Cl-IIR, CPE, E.
There is no particular limitation as long as it is made of a rubber material such as PDM, CSM, or CR, is adhered to the material of the inner cylinder 2a and the reinforcing layer 3 and has liquid resistance to an internal fluid or the like.
Further, as the material of the reinforcing layer 3, a hard steel wire (piano wire) is used as described above.

The material of the outer surface layer 4 is CR or SB.
There is no particular limitation as long as it is a weather-resistant rubber material such as R, CSM, EPDM, CPE, and Cl-IIR. The inner cylinder 2a and the outer cylinder 2b of the inner surface layer 2 have a wall thickness of 0.1
.About.0.5 mm, and the outer cylinder 2b preferably has a thickness of 1.0 to 0.3 mm. If the total thickness of the inner surface layer 2 is 0.5 mm or less, there is a problem that pinholes are easily formed. In addition, the wall thickness of the inner cylinder 2a is preferably equal to or smaller than that of the outer cylinder 2b.

Next, the pressure resistance of the hose body 1 and the reinforcing layer 3
The relationship with the outer diameter of is explained. P: breaking pressure of the hose kgf / cm ² α / 2: braid angle of the reinforcing layer D: center diameter of 〃 cm n: number of wires T: load when cutting wire kgf / piece, P is (1) α When / 2 is smaller than the static angle (54.75 °)

[0012] (2) When α / 2 is larger than the static angle (54.75 °)

[0013] Required by. As can be seen from the above equation, the breaking pressure P becomes large by decreasing the center diameter D of the reinforcing layer. That is, there is a relationship in which the center diameter D can be reduced and the breaking pressure P can be increased by reducing the wall thickness of the inner surface layer (= tube).

In the present invention, the central diameter D of the reinforcing layer is reduced, and the breaking pressure P is increased, so that the number of wires n is reduced or the cutting load T of the wire is reduced (= the wire diameter of the wire is By making it thinner, the weight was reduced and the outer diameter of the hose was reduced. Therefore, the material and thickness of the inner surface layer 2 are defined so that pinholes do not occur even if the thickness of the inner surface layer 2 is reduced.

Next, Examples 1 and ² of hydraulic high pressure hoses for a normal pressure of 210 Kgf / cm ² and Comparative Examples 1 and 2 (conventional products).
Is shown in Table 1.

[0016] As is clear from Table 1 above, when comparing the hose inner diameter of 6.4 mm (Example 1, Comparative Example 1) and 12.7 mm (Example 2, Comparative Example 2), the hose inner diameter of 6.4 mm was measured. Example 1,
In Comparative Example 1, the outer diameter of the hose could be reduced by about 20%, the weight could be reduced by 40%, and the minimum bending radius could be reduced by about 21%.

Also, in the comparative performance test, the bending force can be made smaller than that of the conventional product, and the handling becomes easy. In addition, in Example 2 and Comparative Example 2 in which the inner diameter of the hose is 12.7 mm, the outer diameter of the hose can be reduced by about 12%.
The weight can also be reduced by 28%, and the minimum bending radius is about 14
I was able to make it smaller. Also, in the comparative performance test, it was found that the breaking pressure and the bending force were superior to the conventional product.

[0018]

As described above, according to the present invention, the inner surface layer is composed of an inner cylinder and an outer cylinder each made of a synthetic resin material or a rubber material or a mixture of a synthetic resin material and a rubber material. Since the layer is made of steel wire and the outer surface layer is made of a synthetic resin material alone, a rubber material alone or a mixture of a synthetic resin material and a rubber material, it is possible to thin the inner surface layer and reduce the weight of the hose body. In addition to making the diameter smaller, the outer diameter of the reinforcing layer can be made smaller and the minimum bending radius can be set smaller, pinholes on the inner surface layer can be effectively prevented, and resource saving can be achieved. In addition, the material cost can be reduced.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of a high pressure hose for hydraulic pressure embodying the present invention.

[Explanation of Codes] 1 hose body 2 inner surface layer 2a inner cylinder 2b outer cylinder 3 reinforcing layer 4 outer surface layer 5 adhesive layer

Claims (1)

[Claims] 1. A high-pressure hydraulic hose having a reinforcing layer between an inner surface layer and an outer surface layer, wherein the inner surface layer is made of a synthetic resin material alone, a rubber material alone, or a mixture of a synthetic resin material and a rubber material. It is composed of a cylinder and an outer cylinder, the reinforcing layer is composed of steel wire, and the outer surface layer is composed of a synthetic resin material alone or a rubber material alone or a mixture of a synthetic resin material and a rubber material. High pressure hose for hydraulic pressure.