JPH0538310Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] This invention relates to a hose with excellent flexibility, kink resistance, etc.

[Conventional technology]

Conventionally, hoses used for high-pressure transmission systems or high-pressure fluid transport systems, such as hydraulic hoses and refrigerant transport hoses, have been coated with natural fibers or synthetic fibers on the outside of the inner tube to withstand high pressure. A pressure-resistant reinforcing layer is provided by braiding or spiral winding, and an outer covering layer is extruded on top of the pressure-resistant reinforcing layer. In this case, reasons for providing the outer covering layer include, for example, prevention of disturbance and damage to the fibrous reinforcing layer, as well as the need for weather resistance, chemical resistance, and the like.

However, in the hose with the above structure, the outer covering layer is formed by extrusion coating, so there is a limit to reducing the thickness of the outer covering layer from a manufacturing standpoint. This is an impediment to weight reduction. Furthermore, it is inevitable that the hose will meander slightly when covering the outer layer.
As a result, the outer covering layer does not cover the hose uniformly in the longitudinal or radial direction, and stress tends to concentrate locally when the hose is bent. As the outer cover layer of the fibrous reinforcement layer provided on the inside of the layer significantly reduces the pressing effect from the outside, the fibrous reinforcement layer becomes easily disturbed, and this causes the hose to be bent below a certain bending radius. A drawback is that sometimes a sharp bend, a so-called kink phenomenon, occurs. Kink phenomenon is when the inside of a bent part of a hose causes wall buckling and bending at a certain point, which causes pressure loss and poor pressure resistance, and also tends to cause premature failure at the broken part.
Extremely dangerous poses a condition.

[Problem that the invention attempts to solve]

Therefore, in view of the problems of the prior art described above, the purpose of this invention is to provide a lightweight hose that has excellent flexibility and kink resistance.

[Means for solving problems]

This invention was made in order to solve the problems of the prior art, and therefore, according to this invention, in a hose in which a fibrous reinforcing layer and an outer covering layer are sequentially provided on the outside of an inner tube, the above-mentioned The outer cover layer is characterized in that a thermoplastic resin tape is spirally wound around the outer periphery of the fibrous reinforcing layer so that a portion of the tape overlaps in the width direction, and is integrated by heat fusion.

[Effect]

According to this invention, as described above, a tape made of thermoplastic resin is wound around the outer peripheral surface of a pressure-resistant reinforcing layer made of fibers, and the tape-wrapped layer is integrated by heat fusion to form an outer covering layer. Because it is a thing,
Compared to hoses that have an outer covering layer formed using the conventional extrusion method, the outer covering layer can be coated thinner and more uniformly, making it possible to not only reduce the weight of the hose, but also greatly increase the flexibility of the hose. improves.

Furthermore, since the outer covering layer is made by winding a thermoplastic resin tape, the tape contracts in its longitudinal direction during heat fusion, and the pressure-resistant reinforcing layer is uniformly distributed from the outer periphery over the entire length of the hose. As a result of strong tightening, even if the thickness of the outer covering layer is thinner than that formed by extrusion molding, disturbance of the pressure-resistant reinforcing layer is effectively prevented. Therefore, there is no local concentration of stress during bending, so the kink resistance is greatly improved, and the pressure resistance of the hose is also improved.

〔Example〕

The figure shows an embodiment of the hose according to this invention.
FIG. 3 is a perspective view with an end cut away. Hose 1 shown
A fibrous reinforcing layer 3 made of braided fibers such as polyester fibers is provided on the outer periphery of an inner tube 2 made of thermoplastic resin or rubber, and a thermoplastic resin tape made of polyamide, polyester, etc. is provided on the outer periphery of the layer 3. After spirally winding 4, the outer covering layer 5 is fused and integrated by heat treatment.
It has a structure that has formed the following.

In this case, the outer covering layer 5 is a thermoplastic resin tape 4
Because it is formed by winding, it is much thinner than the extrusion method, and can be coated with uniform thickness in the length direction, and the thickness can be adjusted very easily. Therefore, by covering the outer cover layer 5 thinly, a lightweight hose with excellent flexibility can be obtained. In addition, the tape 4 shrinks at least in the longitudinal direction during heat-sealing, and the outer covering layer 5 tightens the inner reinforcing layer 3 from the outside to effectively prevent the reinforcing layer 3 from being disturbed, thereby preventing kink of the hose. This not only improves properties but also has the effect of improving pressure resistance.

In addition, since the molecular chains of the thermoplastic resin tape 4 are oriented in the extrusion direction, that is, in the longitudinal direction of the tape during melt molding, the thermoplastic resin tape 4 has the property of shrinking to a considerable extent in the longitudinal direction when heated, even without additional stretching treatment. However, if a stretched material is used, the shrinkage during heat-sealing will be large, so the effects on these properties will be even greater, which is advantageous.
Furthermore, if the tape 4 is made of the same material as the fibers forming the fibrous reinforcing layer 3, the two will be fused and integrated when the tape 4 is heat fused, thereby further improving the kink resistance. It is also effective.

[Effect of idea]

As explained above, according to this invention, a thermoplastic resin tape that shrinks in the longitudinal direction when heated is used as the outer covering layer of the hose, and the tape layer is heated while being wrapped around the outer periphery of the fibrous reinforcing layer. Since it is formed by fusing, it is possible to cover the outer layer thinner and more uniformly than in the past, resulting in a lightweight and highly flexible hose.

Furthermore, the outer covering layer has a uniform thickness even when it is thinly coated, and the shrinkage of the thermoplastic resin tape during heat fusion presses the fibrous reinforcing layer inward from the outer peripheral surface, so the outer covering layer has a uniform thickness. The hose not only has excellent kink resistance by well compensating for the deterioration in properties due to the decrease in layer thickness, but also has improved pressure resistance, and its practical effects are extremely large.

Note that this invention is not limited to the above-mentioned embodiments, and may be modified within the technical concept of this invention, such as wrapping multiple thermoplastic resin tapes in different directions or using multiple fibrous reinforcing layers. Of course, various modifications are possible.

[Brief explanation of the drawing]

The figure shows an embodiment of the hose according to this invention.
The end portion is a cutaway perspective view. 2... Inner layer tube, 3... Fibrous reinforcement layer, 4
... Thermoplastic resin tape, 5 ... Outer covering layer.

Claims (1)

[Scope of utility model registration request] In a hose comprising a fibrous reinforcing layer and an outer covering layer sequentially provided on the outside of an inner tube, the outer covering layer is formed by spirally wrapping a thermoplastic resin tape around the outer periphery of the fibrous reinforcing layer so that a portion of the tape in the width direction overlaps with the outer periphery of the fibrous reinforcing layer. A hose characterized by being made of a material that is rolled up and integrated by heat fusion.