JP2008281092A - Rubber hose - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber hose which can suppress the progress of the fracture of a pressure resistive reinforcing layer and a rubber without deteriorating the flexibility of the rubber hose. <P>SOLUTION: A helical reinforcing wire 3 for keeping the circular cross sectional shape of the hose, and pressure resistive reinforcing layers 4, 5 are buried in the tubular rubber 2. Further, a steel cord 6 is buried helically on the outer peripheral side than the pressure resistive reinforcing layer 5. The reinforcing wire 3 does not stick to the surrounding rubber 2, and the pressure resistive reinforcing layer 5 is pressed by the steel cord 6 so as to form a bellows shape so as not to deteriorate the flexibility of the rubber hose 1. The steel cord 6 is integrated with the surrounding rubber 2. As a result, even if a part of the rubber hose 1 has fractured, the steel cord 6 does not come out of the rubber 2, and the progress of the fracture of the rubber hose 1 can be suppressed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rubber hose that is used, for example, as a tip hose for placing ready-mixed concrete.

  In general, a rubber hose used as a tip hose for placing ready-mixed concrete is provided with a reinforcing wire for keeping the cross section of the hose circular and a pressure-resistant reinforcing layer for withstanding internal pressure and a tensile load in the hose central axis direction. (For example, Patent Document 1).

  FIG. 3 shows a cross-sectional view of a main part of a ready-mixed concrete hose disclosed in Patent Document 1. The ready-mixed concrete hose 101 embeds a reinforcing wire 103 in a tubular rubber 102 so as to surround the central axis of the hose in a spiral shape, and a pressure-resistant reinforcing layer 104 on the inner peripheral side and the outer peripheral side of the reinforcing wire 103. , 105 are provided.

A reinforcing tape 106 made of an aramid fiber cord or the like is wound around the outer peripheral side of the pressure-resistant reinforcing layer 105 on the outer peripheral side and between the reinforcing wires 103. The reinforcing tape 106 is configured in a bellows shape by pressing the pressure-resistant reinforcing layer 105 on the outer peripheral side, thereby improving the flexibility of the ready-mixed concrete placing hose and improving the ready-working performance. .
JP 2001-99361 A (paragraph numbers 0003, 0004, 0017, 0019, FIG. 1)

  However, rubber hoses that require high flexibility, such as the ready-mixed concrete hose of Patent Document 1, often do not bond their reinforcing wires to the surrounding rubber. When damaged, the reinforcing wire is pulled out from the rubber by the tensile load acting on the rubber hose. In this case, the pressure-proof reinforcing layer and the damaged portion of the rubber spread, and the internal ready-mixed concrete may fall, or the reinforcing wire may be cut by an impact and the rubber hose itself may fall.

  An object of the present invention is to provide a rubber hose capable of suppressing the progress of damage even when the pressure-resistant reinforcing layer and rubber are damaged without impairing flexibility.

  In order to achieve the above object, the rubber hose according to the present invention embeds a reinforcing wire for surrounding the hose central axis in a spiral shape and keeping the hose cross-section circular in a tubular rubber. The steel cord is not bonded to the rubber, and a steel cord that surrounds the hose central shaft in a spiral shape is embedded so as to be positioned between the reinforcing wires, and this steel cord is integrated with the surrounding rubber.

  According to the above configuration, since the steel cord is integrated with the rubber, even if a part of the rubber hose is broken, the steel cord does not come out of the rubber, and the steel cord can suppress the progress of the rubber hose breakage. it can. Further, since the steel cord is embedded in a spiral shape so as to be positioned between the reinforcing wires, the inclination angle with respect to the central axis of the hose is extremely large and flexible, so that the flexibility of the rubber hose is not impaired. Further, the steel cord having a large inclination angle with respect to the hose central axis is not subjected to a large force due to internal pressure or tensile load until a part of the rubber hose is broken, and the steel cord can be kept healthy.

  In addition, the steel cord generally used has sufficient breaking strength 4 to 5 times that of the polyester fiber and 2 to 3 times that of the aramid fiber. In addition, steel cords are made by twisting together multiple strands. When rubber penetrates between the strands, the steel cord is 2 to 3 times stronger than synthetic fibers and strong with surrounding rubber. Can be integrated. In addition, the steel cord has a large strength, and since sufficient strength can be obtained with a small number of wires, there is no need to forcibly arrange a large number of wires in a narrow space between the reinforcing wires, and the flexibility of the rubber hose is impaired. There is nothing. Thereby, the steel cord can exhibit an effect that cannot be obtained from the reinforcing tape included in the conventional rubber hose, which suppresses the progress of breakage without impairing the flexibility of the rubber hose.

  One steel cord may be embedded between the reinforcing wires, but if multiple steel cords are embedded between the reinforcing wires, the strength per steel cord can be reduced, or a rubber hose. When a part of the rubber hose is damaged, the length and the diameter of the rubber hose can be set larger as much as it can withstand a stronger tensile load.

  If a steel cord is embedded so that it is configured in a bellows shape by pressing the pressure-resistant reinforcing layer on the outer peripheral side from the outer peripheral side while providing a pressure-resistant reinforcing layer on the inner peripheral side and outer peripheral side of the reinforcing wire, a common steel cord In addition, it is possible to provide a function of suppressing the progress of breakage of the pressure-resistant reinforcing layer and rubber and a function of enhancing the flexibility by making the pressure-resistant reinforcing layer bellows.

  The tip of the ready-mixed concrete hose, which has a metal fitting attached to the end, acts as a strong tensile load due to the large internal pressure and the weight of the ready-mixed concrete, and is hung from a high position. In many cases, it is particularly preferable to adopt the configuration of the present invention. That is, by adopting the configuration of the present invention, even if the tip hose for placing the ready-mixed concrete is damaged, the progress of the damage can be suppressed and the ready-mixed concrete can be prevented from falling.

  As described above, according to the present invention, the steel cord is helically embedded so as to be positioned between the reinforcing wires and integrated with the rubber, so that the reinforcing wire is not bonded to the rubber and the flexibility of the rubber hose is improved. In the unlikely event that the rubber hose is broken, the steel cord can suppress the breakage of the pressure-resistant reinforcing layer and rubber.

  Hereinafter, the best mode for carrying out a rubber hose according to the present invention will be described with reference to the drawings. FIG. 1 is a view showing a rubber hose according to the present invention, in which an upper half is a sectional view and a lower half is a side view. FIG. 2 is a diagram showing a state in which the rubber hose is broken. The upper half is a sectional view and the lower half is a side view.

  The rubber hose 1 is used, for example, as a tip hose for placing ready-mixed concrete with a metal fitting attached to the end, and a reinforcing wire 3 for keeping the cross section of the hose circular in a tubular rubber 2. The pressure-resistant reinforcing layers 4 and 5 are arranged on the inner and outer peripheral sides of the reinforcing wire 3 to withstand the internal pressure and the tensile load in the hose central axis direction, and are arranged on the outer peripheral side of the outer peripheral pressure-resistant reinforcing layer 5 Thus, the rubber 2 and the steel cord 6 for suppressing the progress of breakage of the pressure-proof reinforcing layers 4 and 5 are embedded.

  The reinforcing wire 3 is a steel wire having rigidity necessary for maintaining a circular cross section of the hose, is embedded so as to surround the hose central axis in a spiral shape, and is not bonded to the surrounding rubber 2 so that the rubber hose 1 Increases flexibility. For example, when the inner diameter of the rubber hose 1 is 96 mm, the reinforcing wire 3 has a wire diameter of 2.5 mm or more and a helical pitch of 15 mm or less. The rubber 2 is not particularly limited, and natural rubber (NR) and butadiene rubber (BR) can be exemplified.

  The pressure-resistant reinforcing layers 4 and 5 are made of synthetic fibers such as polyamide and polyester. Among these, the pressure | voltage resistant reinforcement layer 4 of an inner peripheral side is made into the cylindrical shape distribute | arranged so that the reinforcement wire 3 may be contacted from the inner peripheral side. Further, the outer peripheral pressure-resistant reinforcing layer 5 is pressed from the inside and outside by an inner peripheral reinforcing wire 3 and an outer peripheral steel cord 6 and is formed in a bellows shape. Furthermore, the outer peripheral surface of the rubber hose 1 is formed in a bellows shape together with the bellows shape of the pressure-resistant reinforcing layer 5, and the flexibility of the rubber hose 1 is enhanced.

  The steel cord 6 is formed by twisting a plurality of strands, and is embedded so as to spirally surround the hose central axis located between the outer peripheral side pressure-resistant reinforcing layer 5 and the reinforcing wire 3, When the rubber 2 enters between the strands, it is firmly integrated with the surrounding rubber 2. Here, the steel cord 6 has an extremely large inclination angle with respect to the central axis of the hose, so that the flexibility of the rubber hose 1 is not impaired, and a strong force acts until the rubber hose 1 is broken. It remains healthy as long as there is not.

  As shown in FIG. 2, when the rubber 2 and the pressure-resistant reinforcing layers 4 and 5 are broken and the rubber hose 1 has a tear 7, the steel cord 6 is broken across the tear 7 without coming out of the rubber 2. Suppress the progress of. The steel cord 6 is set to a strength of, for example, 300 kgf / piece so that it can resist a tensile load due to the weight of the rubber hose 1 and the ready-mixed concrete after the rubber hose 1 is broken.

  According to the above configuration, the steel cord 6 is embedded in a spiral shape so as to be positioned between the reinforcing wires 3 and is firmly integrated with the surrounding rubber 2, so that the rubber 2 and the pressure-resistant reinforcing layers 4 and 5 Even if the rubber hose 1 is broken and the tear 7 is generated, the tear 7 can be prevented from spreading.

  Thereby, for example, when placing the ready-mixed concrete by hanging the tip hose as the rubber hose 1 from the boom of the concrete pump car, the ready-mixed concrete flowing inside the tip-out hose is blocked, and the rise of the internal pressure causes the rubber 2 and the pressure resistance. Even if the reinforcing layers 4 and 5 are damaged, it is possible to prevent the ready-mixed concrete from dropping from the tear 7 of the rubber hose 1 and the rubber hose 1 from being cut and dropped. That is, after the internal pressure is reduced due to the damage of the rubber hose 1, the steel cord 6 can withstand the tensile load due to the weight of the rubber hose 1 and the internal ready-mixed concrete, and the progress of the damage of the rubber hose 1 can be suppressed.

  In addition, since the rigid reinforcing wire 3 is not bonded to the rubber 2 and a flexible steel cord 6 is embedded, the flexibility of the rubber hose 1 is not impaired, and workability such as placing concrete is improved. Can be increased.

  Furthermore, the steel cord 6 has a strength greater than that of the synthetic fiber and the like, and since it is possible to obtain a sufficient strength with a small number, it is not necessary to forcibly arrange a large number in the narrow space between the reinforcing wires 3. The flexibility of the rubber hose 1 is not impaired.

  More specifically, for example, when a rubber hose (tip hose) 1 having an inner diameter of 96 mm and a length of 7 m is damaged near a fitting fastened to the end thereof, the hose weight is about 30 kgf and the internal hose weight is about 30 kgf. If the concrete weight is about 130 kgf and the safety factor considering the impact coefficient is 1.5, the rubber hose 1 after breakage is required to withstand a load of (30 kgf + 130 kgf) × 1.5 = 240 kgf.

  On the other hand, the general steel cord 6 has a strength of about 200 to 300 kgf / piece, and it is sufficient to arrange one or two steel cords 6 to withstand a load of 240 kgf. .

  On the other hand, general polyester fibers have a strength of about 20 to 30 kgf / fiber and a fiber diameter of about 0.8 mm. In order to endure a load of 240 kgf, about 10 polyester fibers are used between the reinforcing wires 3. This polyester fiber will occupy a space of at least 8 mm. Further, general aramid fibers have a strength of about 50 to 60 kgf / fiber and a fiber diameter of about 0.8 mm, and in order to withstand a load of 240 kgf, about 5 aramid fibers are used between the reinforcing wires 3. This aramid fiber will occupy a space of at least 4 mm.

  Furthermore, when the inner diameter of the rubber hose 1 is 96 mm and the helical pitch of the reinforcing wires 3 is 15 mm or less and the wire diameter is 2.5 mm or more, the space between the reinforcing wires 3 is only 12.5 mm at the maximum. Therefore, even if it tries to embed synthetic fiber, such as polyester fiber and aramid fiber, instead of steel cord 6, it will be forcibly arranged in a narrow space and the flexibility of rubber hose 1 will be impaired.

  Moreover, while the steel cord 6 has a sufficient adhesive strength with the rubber 2, the synthetic fiber has an adhesive strength with the rubber 2 of only about 1/2 to 1/3 that of the steel cord 6. Even if the synthetic fiber does not break, the tear 7 is likely to spread due to the synthetic fiber coming out of the rubber 2.

  In addition, this invention is not limited to said embodiment, A change can be suitably added within the scope of the present invention. For example, instead of embedding one steel cord 6 between the reinforcing wires 3, a plurality of steel cords 6 can be embedded between the reinforcing wires 3. For example, by embedding two steel cords 6, a steel cord 6 having a strength of 200 kgf can be used instead of a steel cord 6 having a strength of 200 kgf.

The figure which shows the rubber hose which concerns on this invention, an upper half is sectional drawing, a lower half is a side view The rubber hose is broken. The upper half is a cross-sectional view and the lower half is a side view. Cross section of the main part of a conventional rubber hose

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rubber hose 2 Rubber 3 Reinforcement wire 4, 5 Pressure-resistant reinforcement layer 6 Steel cord 7 Rupture

Claims (4)

  A rubber hose in which a reinforcing wire for enclosing a hose central axis in a spiral shape and keeping a circular cross section of the hose is embedded in a tubular rubber, the reinforcing wire being non-bonded to the surrounding rubber, A rubber hose in which a steel cord surrounding a hose central axis in a spiral shape is embedded so as to be positioned between wires, and the steel cord is integrated with surrounding rubber.   The rubber hose according to claim 1, wherein a plurality of steel cords are embedded between the reinforcing wires.   A pressure-resistant reinforcing layer is provided on an inner peripheral side and an outer peripheral side with respect to the reinforcing wire, and the steel cord is embedded so as to press the outer peripheral pressure-resistant reinforcing layer from the outer peripheral side to have a bellows shape. Item 3. A rubber hose according to Item 1 or 2.   The rubber hose according to claim 1, 2 or 3, wherein a metal fitting is fastened to an end portion and used as a tip hose for placing ready-mixed concrete.

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