Resin Composite Hose and Method for Producing the Same

Abstract

A resin composite hose includes a curved portion at an axial position thereof, and has a multilayer construction including a resin layer having permeation resistance to a transported fluid and serving as a barrier layer, an inner rubber layer and an outer rubber layer. The curved portion has a shape of progressively increasing a circumferential length while being flattened progressively increasingly from a curve beginning end of a perfect circle in cross-section to a curve terminal end or a curve middle portion of a flattened circle.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a resin composite hose according to one embodiment of the present invention, showing partly broken away.

FIG. 2A is an overall perspective view showing the resin composite hose of FIG. 1.

FIG. 2B is a view showing a change in shapes of a-a section, b-b section and c-c section of FIG. 2A.

FIG. 2C is a cross-sectional view of a straight portion of the resin composite hose.

FIG. 3A is a view of a curved portion of the resin composite hose.

FIG. 3B is a view showing a change in shapes of a-a section, b-b section and c-c section of FIG. 3A.

FIG. 4A is a view showing a relevant step of a method for producing the resin composite hose according to the present invention.

FIG. 4B is a view showing a change in shapes of a-a section, b-b section and c-c section of FIG. 4A.

FIG. 5A is a view for explaining a disadvantage of a conventional resin composite hose.

FIG. 5B is a view for explaining an advantage of the resin composite hose of the present invention.

FIG. 6 is a perspective view of a modified resin composite hose according to the present invention.

FIG. 7 is a perspective view of another modified resin composite hose according to the present invention.

FIG. 8A is a sectional view of a conventional resin composite hose.

FIG. 8B is an enlarged view of a part of the conventional resin composite hose of FIG. 8A.

FIG. 9 is a view showing a typical production method for producing a conventional resin composite hose of curved shape.

FIG. 10A is a view showing a multilayer construction of a tubular hose body.

FIG. 10B is a view for explaining a failure occurred in the conventional resin composite hose of curved shape.

Claims

1. A resin composite hose including a curved portion at an axial position thereof, and having a multilayer construction, comprising: a resin layer having permeation resistance to a transported fluid and serving as a barrier layer, an inner rubber layer as an inner surface layer laminated on an inner side of the resin layer and an outer rubber layer laminated on an outer side of the resin layer,wherein:the curved portion has a shape of progressively increasing a circumferential length while being flattened progressively increasingly from a curve beginning end of a perfect circle in cross-section to a curve terminal end or a curve middle portion of a flattened circle such as an ellipse or an elongated circle in cross-section, a cross-sectional area of a fluid path of the curve beginning end is set a minimum cross-sectional area of a fluid path through the curved portion from the curve beginning end to the curve middle portion.

2. The resin composite hose as set forth in claim 1, wherein any cross-sectional shape of the curved portion has a first axis passing from side to side thereof through a center thereof and a second axis passing from side to side thereof through the center thereof and perpendicular to the first axis, the curved portion is flattened progressively increasingly from the curve beginning end to the curve terminal end in such a manner that the first axis of the cross-sectional shape is maintained constant and the second axis thereof is progressively increased

3. The resin composite hose as set forth in claim 2, wherein a second curved portion is provided at an axial position other than the axial position of the curved portion as a first curved portion, and the second curved portion is formed as a cross-sectional shape transitional portion so as to be progressively changed in a cross-sectional shape from a flattened circle of a cross-sectional shape of a curve beginning end thereof to a perfect or nearly perfect circle of a cross-sectional shape of a curve terminal end or a curve middle portion thereof.

4. The resin composite hose as set forth in claim 3, wherein a straight portion is provided between the first curved portion and the second curved portion, the straight portion extends straight in an axial direction of the resin composite hose with a cross-sectional shape thereof being maintained in a flattened circle identical to a cross-sectional shape of the curve terminal end of the first curved portion.

5. Method for producing the resin composite hose as defined in claim 1, comprising: a step of forming a tubular hose body of a straight shape with the multilayer construction by successively laminating the inner rubber layer, the resin layer and the outer rubber layer on one another by extrusion, the tubular hose body being plastically deformable and the tubular hose body being unvulcanized or semivulcanized,a step of preparing a mandrel having a shape corresponding to a shape of an inner surface of the resin composite hose including the curved portion,a step of relatively fitting the tubular hose body on the mandrel and deforming the tubular hose body to obtain a tubular hose body of curved shape, anda step of vulcanizing the tubular hose body of curved shape to obtain the resin composite hose including the curved portion.