Flexible hose and method for manufacturing the same

Abstract

To enhance the strength of a flexible hose.SOLUTION: A flexible hose (1) is structured by spirally winding a flexible strip band (2) and caulking and joining it with a metallic strip band (3). A flexible strip band first folded part (21) is provided on the flexible strip band (2), and a metallic strip band first folded part (31) is provided on the metallic strip band (3). The metallic strip band (3) has, in an internal peripheral part (33), a first flat plate part (33b), a second flat plate part (33c), and a protrusion part (33a) which is provided between the first flat plate part (33b) and the second flat plate part (33c) and protrudes to the outside of the hose. A width of the protrusion part (33a) is equal to or greater than 1 / 5 and equal to or smaller than 3 / 5 of a width of the internal peripheral part (33). The metallic strip band is caulked with a terminal end (31a) of the metallic strip band first folded part (31) being located inside the flexible strip band first folded part (21), and the flexible strip band (2) is held between the terminal end (31a) of the metallic strip band first folded part and the protrusion part (33a) of the metallic strip band.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a flexible hose in which a flexible strip of a predetermined width is wound in a spiral shape, and the edge portions of the flexible strips adjacent to each other are caulked and joined by a metal strip.

Background Art

[0002] A flexible hose in which a flexible strip of a predetermined width is wound in a spiral shape, and the edge portions of the flexible strips adjacent to each other are caulked and joined by a metal strip is used for applications such as air ducts. Such a flexible hose is lightweight, has excellent flexibility, and is not easily crushed.

[0003] For example, Patent Document 1 discloses a technique of a flexible duct in which an inorganic fiber woven fabric strip having a predetermined fiber structure is wound in a spiral shape and caulked and joined by a metal strip. According to the flexible duct, it is disclosed that the strength of a heat-resistant flexible duct can be improved.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a flexible hose with a structure like that described in Patent Document 1, the metal strip portion functions as a reinforcement for the hose, and the woven flexible strip portion functions as a flexible hose wall. However, in a hose crimped together with a metal strip as described in Patent Document 1, the crimped joint is prone to being insufficient. If the crimping is insufficient, the flexible strip may come loose from the crimped part when the hose is bent or pulled. Alternatively, if the crimping is insufficient, the flexible strip and the metal strip may shift along the wound spiral, and the flexible strip and the metal strip may come apart at the end of the hose.

[0006] In particular, for flexible hoses used in applications requiring high heat resistance, non-flammability, and fire resistance, the flexible strips also need to possess high heat resistance and fire resistance. In such fields, the use of woven fabric materials containing inorganic fibers, such as glass fibers, as flexible strips can be considered. However, while these inorganic fiber woven fabrics have advantages in terms of flame retardancy, they lack elasticity and friction, making it difficult to sufficiently increase the joint strength of the crimped portion in crimped joint structures such as the flexible hose described in Patent Document 1.

[0007] The object of the present invention is to increase the joint strength of the crimped portion in a flexible hose having a crimped connection structure. Another object of the present invention is to provide a flexible hose with less airflow resistance for the air passing through it. [Means for solving the problem]

[0008] After diligent investigation, the inventor discovered that in the area where the metal strip is crimped, the crimped metal strip tends to spring back, resulting in insufficient clamping of the flexible strip.

[0009] The inventors conducted further studies and discovered that in a hose with a crimped joint structure, if a protruding ridge is provided on the inner circumference of the metal strip that projects outward from the hose, and a flexible strip is sandwiched between the end of the folded portion of the metal strip and the protruding ridge of the metal strip, the joint strength of the crimped portion can be increased, thus completing the present invention.

[0010] The present invention relates to a flexible hose in which a flexible strip of a predetermined width is wound spirally while being folded into a predetermined shape, and the ends of adjacent flexible strips are crimped and joined together with a metal strip, wherein at the crimped joint, the flexible strip is provided with a first folded portion of the flexible strip that is folded towards the inside of the hose and toward the center of the flexible strip, and the metal strip is provided with a first folded portion of the metal strip that is folded towards the outside of the hose and toward the center of the metal strip, and the metal strip is provided on the inner circumference so as to face the inside of the hose The flexible hose has a section, the inner circumference having a first flat plate section and a second flat plate section extending parallel to the central axis of the hose, and a protruding section provided between the first flat plate section and the second flat plate section so as to protrude to the outside of the hose, the width of the protruding section being 1 / 5 or more and 3 / 5 or less of the width of the inner circumference, the end of the first folded section of the metal strip is located inside the first folded section of the flexible strip, the first folded section of the metal strip is crimped, and the flexible strip is sandwiched between the end of the first folded section of the metal strip and the protruding section of the metal strip (first invention).

[0011] In the first invention, preferably, the flexible strip is provided with a second folded portion of the flexible strip on the side edge opposite to the first folded portion of the flexible strip, which is folded back toward the inside of the hose and toward the center of the flexible strip, and the metal strip is provided with a second folded portion of the metal strip on the side edge opposite to the first folded portion of the metal strip, which is folded back toward the outside of the hose and toward the center of the metal strip, and the end of the second folded portion of the metal strip is located inside the second folded portion of the flexible strip, and the second folded portion of the metal strip is crimped, so that the flexible strip is sandwiched between the end of the second folded portion of the metal strip and the protruding portion of the metal strip (second invention). Furthermore, in the first or second invention, preferably, in the inner circumference of the metal strip, the first flat portion and the second flat portion are located on the same cylindrical surface (third invention). Furthermore, the present invention is a method for manufacturing a flexible hose according to the first invention, comprising a protruding portion forming step of forming a protruding portion in the center of the width direction of a flat metal strip, and a first crimping step after the protruding portion forming step, in which the end of the first folded portion of the metal strip is crimped so that the end of the first folded portion of the metal strip is located inside the first folded portion of the flexible strip, thereby sandwiching the flexible strip between the end of the first folded portion of the metal strip and the protruding portion of the metal strip (fourth invention). Furthermore, the present invention relates to a flexible hose in which a flexible strip of a predetermined width is wound spirally while being folded into a predetermined shape, and the ends of adjacent flexible strips are crimped together with a metal strip, wherein at the crimped joint, the flexible strip is provided with a first folded portion of the flexible strip that is folded towards the outside of the hose and toward the center of the flexible strip, and the metal strip is provided with a first folded portion of the metal strip that is folded towards the inside of the hose and toward the center of the metal strip, and the metal strip is provided so as to face the outside of the hose The flexible hose has a circumferential portion, the circumferential portion having a first flat plate portion and a second flat plate portion extending parallel to the central axis of the hose, and a protruding portion provided between the first flat plate portion and the second flat plate portion so as to protrude inward into the hose, the width of the protruding portion being 1 / 5 or more and 3 / 5 or less of the width of the circumferential portion, and the metal strip first folded portion is crimped so that the end of the metal strip first folded portion is located inside the flexible strip first folded portion, and the flexible strip is sandwiched between the end of the metal strip first folded portion and the protruding portion of the metal strip (5th invention). [Effects of the Invention]

[0012] According to the flexible hose of the present invention (first invention), springback of the folded portion of the metal strip is suppressed, and the joint strength of the crimped portion can be increased. Furthermore, in the case of the second invention, the joint strength of the crimped portions at both ends of the metal strip is increased, and the strength of the flexible hose is particularly enhanced.

[0013] Furthermore, in the case of the third invention, the airflow resistance of the air passing through the inside of the flexible hose can be further reduced. Also, according to the manufacturing method of the fourth invention, a flexible hose with protruding portions on the inner circumference of a metal strip can be efficiently manufactured. In addition, according to the flexible hose of the fifth invention, the joint strength of the crimped portion can be increased, similar to the first invention. [Brief explanation of the drawing]

[0014] [Figure 1]This is a partial cross-sectional view showing the structure of the flexible hose of the first embodiment. [Figure 2] This is a cross-sectional view showing the structure of the crimped portion of the flexible hose according to the first embodiment. [Figure 3] This is a cross-sectional view showing the manufacturing process of the flexible hose according to the first embodiment. [Figure 4] This is a cross-sectional view showing the structure of the crimped portion of the flexible hose according to the second embodiment. [Modes for carrying out the invention]

[0015] The embodiments of the invention will be described below with reference to the drawings, using a flexible hose that can be used as a heat-resistant air supply duct as an example. The invention is not limited to the individual embodiments shown below, and can be implemented in a modified form.

[0016] Figure 1 is a partial cross-sectional view showing the structure of the flexible hose 1 of the first embodiment. The flexible hose 1 is a cylindrical flexible hose in which a flexible strip 2 of a predetermined width is wound spirally while being folded into a predetermined shape, and the ends of adjacent flexible strips are crimped together with a metal strip 3 that is similarly wound spirally. Figure 2 shows a cross-sectional view of the structure of the crimped portion of the flexible hose. Note that in Figures 1 and 2, the strips are shown spaced apart as appropriate to make the folded structure of each strip easier to see.

[0017] The flexible strip 2 and the metal strip 3 are folded at both ends into a predetermined shape, and the folded portions of the flexible strip 2 and the metal strip 3 are wound together in a spiral shape so that they interlock. The folded portion of the metal strip 3 is then crimped, and the flexible strip 2 and the metal strip 3 are joined together to form a cylindrical flexible hose 1.

[0018] In the flexible hose 1, the portion of the flexible strip 2 functions as a flexible hose wall, and the portion of the metal strip 3 functions as a helical reinforcing body that maintains the cylindrical shape of the hose. Also, although not essential, a string-like seal member may be arranged at the portion where the flexible strip 2 and the metal strip 3 are joined by caulking to enhance the sealing performance. Further, a sealant may be applied between the flexible strip 2 and the metal strip 3 to enhance the sealing performance.

[0019] The material constituting the flexible strip 2 is not particularly limited, but preferably, it may be a strip including a resin sheet, a metal foil or a thin metal plate, a woven fabric, a non-woven fabric, etc. When heat resistance is required for the flexible hose, the flexible strip may be selected from materials having the desired heat resistance. For example, the flexible strip may be composed of a composite material in which a woven fabric is coated with a resin. The fibers constituting the woven fabric are not particularly limited, but woven fabrics using natural fibers such as cotton and hemp, synthetic resin fibers such as polyester and polyamide, inorganic fibers such as glass fibers and carbon fibers, and silica fibers can be used. The resin for coating the woven fabric is not particularly limited, and may be a thermoplastic resin such as a vinyl chloride resin, a thermoplastic elastomer, or a thermosetting resin such as a synthetic rubber. Also, the flexible strip may be a material in which a metal foil and a resin are laminated, or a laminated resin sheet in which resin layers of different materials are laminated.

[0020] Also, from the viewpoint of enhancing heat resistance, the flexible strip is preferably a strip including a metal foil or a thin metal plate. The strip including a metal foil or a thin metal plate may be composed of, for example, a stainless steel foil (SUS foil), or may be composed of a composite material in which an aluminum foil (AL foil) is coated with a polyethylene terephthalate resin (PET resin). Such a strip including a metal foil or a thin metal plate can enhance the heat resistance of the hose.

[0021] From the perspective of enhancing the heat resistance and fire resistance of the hose, it is preferable that the woven fabric constituting the flexible strip 2 is mainly composed of inorganic fibers and coated with a silicone resin or a fluororesin. Examples of the inorganic fibers include, but are not limited to, glass fibers, silica fibers, alumina fibers, carbon fibers, ceramic fibers, etc. The woven fabric may contain fibers other than inorganic fibers, such as synthetic resin fibers. The silicone resin is preferably silicone rubber, and the fluororesin is preferably a thermoplastic fluororesin or fluororubber. In the present embodiment, a composite material in which a woven fabric mainly composed of glass fibers is coated with a thermoplastic fluororesin is used as the flexible strip 2 after being cut into strips of a predetermined width.

[0022] The metal strip 3 is composed of a thin plate made of a metal material such as plated iron, stainless steel, aluminum, brass, etc. The metal strip 3 functions as a reinforcing body that exhibits resistance to crushing when it becomes a hose. Also, in order to firmly join the flexible strip 2 and the metal strip 3 by caulking the strip, it is provided with a predetermined thickness. The thickness of the metal strip is typically 0.1 mm to 1.5 mm.

[0023] Hereinafter, the folding shape, caulking joint structure, and seal structure of the flexible strip 2 and the metal strip 3 will be described in detail. In FIG. 2, the upper side of the figure corresponds to the outside of the hose, and the lower side of the figure corresponds to the inside of the hose. Also, for the sake of convenience of explanation, the direction indicated by A in the figure is called one end side of the hose, and the direction indicated by B in the figure is called the other end side of the hose.

[0024] In the flexible hose 1, the metal strip 3 has the edge portion located at one end side of the hose (the strip edge portion on the A side in the figure) and the edge portion located at the other end side of the hose (the strip edge portion on the B side in the figure) folded back. In the metal strip 3, the folded-back portion on the side of the strip edge portion on the B side in the figure is called the first folded-back portion 31 of the metal strip, and the folded-back portion on the side of the strip edge portion on the A side in the figure is called the second folded-back portion 32 of the metal strip.

[0025] The first folded portion 31 of the metal strip is folded back toward the outside of the hose and toward the central portion 35 of the metal strip. In this embodiment, the first folded portion 31 is folded back so as to have a substantially arc-shaped cross-section. The radius of the arc may be constant or it may vary. Note that when we say that the end edge of the strip is folded back toward the outside of the hose and toward the central portion of the strip, we mean that the end edge of the strip is bent toward the outside of the hose and then folded back in a U-shape toward the central portion of the strip. The same applies to the folded portions described below.

[0026] Furthermore, the second folded portion 32 of the metal strip is folded back toward the outside of the hose and toward the central portion 35 of the metal strip.

[0027] Furthermore, the metal strip 3 has an inner circumference 33 that faces the inside of the hose. The inner circumference portion 33 has a first flat plate portion 33b, a second flat plate portion 33c, and a protruding portion 33a. The first flat plate portion 33b extends substantially parallel to the hose's central axis. The second flat plate portion 33c also extends substantially parallel to the hose's central axis. The protruding portion 33a is provided linearly along the length of the metal strip in the center of the inner circumference portion 33 in the width direction. The protruding portion 33a is also provided between the first flat plate portion 33b and the second flat plate portion 33c, and is provided so as to protrude outward from the first flat plate portion 33b and the second flat plate portion 33c.

[0028] In other words, the metal strip 3 is bent so that it has a flattened "3" or "ω" shaped cross-section that opens outwards from the hose. With the metal strip 3 crimped, the first folded portion 31 and the second folded portion 32 of the metal strip extend in the width direction of the strip such that their respective ends 31a and 32a reach the protruding portion 33a. The width of the protruding portion 33a is set to be between 1 / 5 and 3 / 5 of the width of the inner circumference portion 33. Here, "width" refers to the dimension measured in the left-right direction in Figure 2. Furthermore, it is preferable that the height of the protruding portion 33a be between 1 / 4 and 1.0 times the height of the crimped metal strip. Here, "height" refers to the dimension measured in the up-down direction in Figure 2. Furthermore, although not required, it is preferable that the first flat plate portion 33b and the second flat plate portion 33c have approximately the same width.

[0029] In the flexible strip 2, the edge portion of the flexible strip 2 located at one end of the hose (side A in the figure) when viewed as a standalone strip (i.e., the portion that is combined with the first folded portion 31 of the metal strip) is called the first edge portion 2A of the flexible strip. The first edge portion 2A of the flexible strip is provided with the first folded portion 21 of the flexible strip, which is on the inside of the hose and folded back toward the central portion 29 of the flexible strip 2.

[0030] With the end portion 31a of the first folded portion 31 of the metal strip positioned inside the first folded portion 21 of the flexible strip, the first folded portion 31 of the metal strip is crimped, and the flexible strip is sandwiched between the end portion 31a of the first folded portion 31 of the metal strip and the protruding portion 33a of the metal strip, thereby joining the first end edge 2A of the flexible strip 2 and the metal strip 3. Here, "inside the first folded portion 21 of the flexible strip" means that the end portion 31a of the metal strip is positioned inside the pleats of the pleated first folded portion of the flexible strip. The same applies hereafter. Also, in the crimped state, the first folded portion 21 of the flexible strip is positioned between the first folded portion 31 of the metal strip and the first flat portion 33b of the metal strip.

[0031] In the flexible strip 2, the edge portion of the flexible strip 2 located on the other end side of the hose (side B in the figure) when viewed as a standalone strip (i.e., the portion that is combined with the second folded portion 32 of the metal strip) is called the second edge portion 2B of the flexible strip. In this embodiment, the second edge portion 2B of the flexible strip is provided with a second folded portion 22 of the flexible strip that is on the inside of the hose and folded towards the central portion 29 of the flexible strip 2.

[0032] Furthermore, in this embodiment, with the end portion 32a of the second folded portion 32 of the metal strip positioned inside the second folded portion 22 of the flexible strip, the second folded portion 32 of the metal strip is crimped, and the flexible strip is sandwiched between the end portion 32a of the second folded portion 32 of the metal strip and the protruding portion 33a of the metal strip, thereby joining the second end edge 2B of the flexible strip 2 and the metal strip 3.

[0033] The flexible hose 1 can be manufactured by applying known manufacturing methods. First, a flexible strip 2 and a metal strip 3, each in the shape of a ribbon of a predetermined width, are prepared. The flexible strip 2 and the metal strip 3 are each bent into a predetermined folded cross-section, and while being combined so that their folded portions interlock, they are wound in a spiral shape, and the folded portion of the metal strip 3 is crimped to manufacture the flexible hose 1.

[0034] To illustrate the manufacturing process of the flexible hose 1 in more detail, a metal strip 3 is crimped with a flexible strip 2 through the process shown in Figure 3 to produce the hose. The metal strip 3, with a cross-section as shown in Figure 3(a), is processed by being sandwiched between rollers equipped with protrusions and grooves, so that both ends are bent to form a roughly U-shaped cross-section as shown in Figure 3(b), and a protrusion is formed in the center (protrusion formation process). This protrusion later becomes the protrusion portion 33a, and the portions on both sides of the protrusion later become the first flat portion 33b and the second flat portion 33c.

[0035] After the metal strip 3 is provided with the protrusions 33a, the folded edges at both ends are further folded as shown in Figure 3(c). These folded portions will later become the first folded portion 31 and the second folded portion 32 of the metal strip.

[0036] The metal strip 3, in the form shown in Figure 3(c), is fed together with the flexible strip 2 into a winding and crimping device. The metal strip 3 and the flexible strip 2 are then wound into a cylindrical shape and crimped together to manufacture the flexible hose 1. The winding and crimping device uses bending dies, bending rollers, crimping rollers, etc.

[0037] Inside the winding crimping device, the metal strip's first folded portion 31 is crimped with the end portion 31a of the metal strip's first folded portion 31 positioned inside the flexible strip's first folded portion 21 (Figure 3(d)). In Figure 3(d), the crimping operation is indicated by a white arrow. Through crimping, the flexible strip 2 is sandwiched between the end portion 31a of the metal strip's first folded portion 31 and the metal strip's protruding portion 33a, and the first end edge 2A of the flexible strip 2 is joined to the metal strip 3 (first crimping step: Figure 3(d)).

[0038] Inside the winding crimping device, the metal strip's second folded portion 32 is crimped with the end portion 32a of the metal strip's second folded portion 32 positioned inside the flexible strip's second folded portion 22 (second crimping step: Figure 3(e)). In Figure 3(e), the crimping operation is indicated by a white arrow. Through crimping, the flexible strip 2 is sandwiched between the end portion 32a of the metal strip's second folded portion 32 and the metal strip's protruding portion 33a, thereby joining the second end edge 2B of the flexible strip 2 to the metal strip 3.

[0039] In this example of the manufacturing method, the crimping of the first folded portion 31 of the metal strip (Figure 3(d)) is shown to precede the crimping of the second folded portion 32 of the metal strip (Figure 3(e)). However, the order of crimping may be reversed, and the crimping of both locations may be performed approximately simultaneously.

[0040] Through the above process, both ends of the flexible strip 2 are crimped and joined with the metal strip 2, and a flexible hose 1 is manufactured (Figure 3(f)). The above process is carried out continuously using a long metal strip 3 or a long flexible strip 2, and a long flexible hose 1 is continuously manufactured.

[0041] Although not mandatory, it is preferable to perform a first crimping step (Figure 3(d)) after the rib formation step in Figure 3(b), as illustrated in this manufacturing method, in which the end portion 31a of the first folded portion 31 of the metal strip is crimped so that the end portion 31a of the first folded portion 31 of the metal strip is located inside the first folded portion 21 of the metal strip, thereby sandwiching the flexible strip between the end portion 31a of the first folded portion 31 of the metal strip and the rib portion 33a of the metal strip. Similarly, it is preferable to perform the crimping step of the second folded portion 32 of the metal strip (second crimping step: Figure 3(e)) after the rib formation step in Figure 3(b).

[0042] The operation and effects of the flexible hose 1 of the first embodiment described above will now be explained. According to the flexible hose 1, the springback of the folded portion of the metal strip is suppressed, and the joint strength of the crimped portion can be increased.

[0043] In the flexible hose 1 of the first embodiment described above, the flexible strip is sandwiched between the end 31a of the first folded portion 31 of the metal strip and the protruding portion 33a of the metal strip. Therefore, as shown in Figure 2, the radial position of the end 31a of the first folded portion of the metal strip is located radially outward from the radial positions of the first flat portion 33b and the second flat portion 33c. Consequently, the circumference at the position where the end 31a of the first folded portion of the metal strip is located is longer than the circumference at the position where the first flat portion 33b and the second flat portion 33c are located.

[0044] Since the end portion 31a of the metal strip, as well as the first flat portion 33b and the second flat portion 33c, were originally the same length as flat metal strips, the difference in circumference of the positioned portions causes the end portion 31a of the metal strip to be positioned in a relatively stretched state. As a result, tension acts on the end portion 31a of the metal strip, biasing it to tighten against the protruding portion 33a. This tightening action suppresses the springback of the folded portion 31 of the metal strip, thereby increasing the joint strength of the crimped portion.

[0045] As with the flexible hose 1 of the first embodiment described above, the inner circumference 33 of the metal strip has a first flat plate portion 33b, a second flat plate portion 33c, and a protruding portion 33a that is provided to protrude to the outside of the hose, and the width of the protruding portion 33a is 1 / 5 or more and 3 / 5 or less of the width of the inner circumference 33, thereby ensuring that the tightening action described above is reliably achieved.

[0046] Furthermore, as in the embodiment described above, if the second folded portion 32 on the opposite side of the metal strip 3 also has a similar crimping structure, springback will be suppressed on the side of the second folded portion 32 as well, increasing the joint strength of the crimped portion. This will increase the joint strength of the crimped portion at both ends of the metal strip, and in particular, increase the strength of the flexible hose.

[0047] Furthermore, as in the above embodiment, if the first flat plate portion 33b and the second flat plate portion 33c of the metal strip 3 are located on the same cylindrical surface in the inner circumference portion 33, the inner circumference portion 33 of the metal strip exposed on the inner surface of the hose becomes substantially smooth and cylindrical, thereby further reducing the airflow resistance of the air passing through the inside of the flexible hose.

[0048] Furthermore, if the flexible hose 1 of the above embodiment is manufactured in such a way that the first crimping step (Figure 3(d)) is performed after the rib formation step (Figure 3(b)), as illustrated in the manufacturing method, a flexible hose with ribs on the inner circumference of the metal strip can be efficiently manufactured. This is because when ribs 33a are provided on the metal strip 3, more folds are created along the longitudinal direction of the metal strip, making it less likely for the metal strip to bend in the longitudinal direction, and allowing the metal strip to be fed into the winding crimping device more reliably.

[0049] The invention is not limited to the embodiments described above and can be implemented with various modifications. Other embodiments of the invention will be described below, but in the following description, the focus will be on the parts that differ from the embodiments described above, and detailed descriptions of parts that are similar will be omitted. Furthermore, these embodiments can be implemented by combining or substituting parts of each other.

[0050] Figure 4 shows the structure of the crimped portion in the flexible hose 5 of the second embodiment. The flexible hose 5 of the second embodiment has a structure similar to the hose wall structure of the flexible hose 1 of the first embodiment described above, but with the inside / outside reversed.

[0051] In other words, in the flexible hose 5 of the second embodiment, a flexible strip 6 of a predetermined width is wound spirally while being given a predetermined folded shape, and the ends of adjacent flexible strips 6 are crimped together with a metal strip 7. At the crimped joint, the flexible strip 6 is provided with a first folded portion 61 of the flexible strip that is folded back toward the outside of the hose and toward the center of the flexible strip, and the metal strip 7 is provided with a first folded portion 71 of the metal strip that is folded back toward the inside of the hose and toward the center of the metal strip.

[0052] The aforementioned metal strip 7 has an outer circumference 73 that faces the outside of the hose, The outer periphery 73 has a first flat plate portion 73b and a second flat plate portion 73c extending parallel to the central axis of the hose, and a protruding portion 73a provided between the first and second flat plate portions so as to protrude inward into the hose. The width of the protruding portion 73a is set to be between 1 / 5 and 3 / 5 of the width of the outer periphery.

[0053] Then, with the end portion 71a of the first folded portion 71 of the metal strip positioned inside the first folded portion 61 of the flexible strip, the first folded portion 71 of the metal strip is crimped, and the flexible strip 6 is sandwiched between the end portion 71a of the first folded portion 71a of the metal strip and the protruding portion 73a of the metal strip.

[0054] With this structure, similarly, the end 71a of the first folded portion 71 is positioned on the inside of the hose, where the circumference is relatively shorter, relative to the first flat portion 73b and the second flat portion 73c of the metal strip 7, and a force is applied that pushes the end 71a of the first folded portion 71 toward the outside of the hose. As a result, the flexible strip 6 is sandwiched between the end 71a of the first folded portion of the metal strip and the protruding portion 73a of the metal strip, suppressing the springback of the folded portion of the metal strip and increasing the joint strength of the crimped portion.

[0055] Although not essential, in the flexible hose 5 of the second embodiment, the flexible strip 6 is provided with a second folded portion 62 of the flexible strip 6 that is folded back toward the outside of the hose and toward the center of the flexible strip, and the metal strip 7 is provided with a second folded portion 72 of the metal strip 7 that is folded back toward the inside of the hose and toward the center of the metal strip, and the metal strip 7 has an outer circumference 73 that faces the outside of the hose, and the outer circumference has a first horizontal extension parallel to the central axis of the hose The flexible strip has a plate portion 73b, a second flat plate portion 73c, and a protruding portion 73a provided between the first flat plate portion and the second flat plate portion so as to protrude inward into the hose. The width of the protruding portion 73a is 1 / 5 to 3 / 5 of the width of the outer circumference portion 73. The end portion 72a of the second folded portion 72 of the metal strip is located inside the second folded portion 62 of the flexible strip, and the second folded portion 72 of the metal strip is crimped, so that the flexible strip 6 is sandwiched between the end portion 72a of the second folded portion 72 of the metal strip and the protruding portion 73a of the metal strip. This configuration can further increase the joint strength of the hose.

[0056] Although not essential, as in this second embodiment, the second end edge 6B of the flexible strip 6 may also be provided with a fourth folded portion 64 of the flexible strip 6, which is folded back toward the outside of the hose and toward the other end of the hose (right side in the figure), closer to the end edge than the second folded portion 62 of the flexible strip 6. In other words, the second end edge 6B of the flexible strip 6 may be bent in an S-shape. Such a configuration can contribute to improving the joint strength and sealing performance between the flexible strip 6 and the metal strip 7.

[0057] Similarly, although not required, a third folded portion (not shown) of the flexible strip may be provided on the first end edge 6A of the flexible strip, closer to the end edge than the first folded portion 61 of the flexible strip, and folded toward the outside of the hose and toward one end of the hose (left side in the figure). In other words, the first end edge 6A of the flexible strip may be bent in an inverted S shape. If a third folded portion is provided, the joint strength between the first end edge 6A of the flexible strip 6 and the metal strip 3 is improved. The third folded portion may also contribute to improved sealing performance.

[0058] Although not required, if the folded portion of the flexible strip is folded in an S-shape, as in the flexible hose 5 of this second embodiment, the wire 8 may be placed inside the fourth folded portion 64 of the second end edge 6B of the flexible strip, or inside the third folded portion (not shown) of the first end edge 2A of the flexible strip. The wire is not particularly limited, but examples include metal wire, resin wire, and string. When the wire 8 is placed, the joint strength between the first end edge 6A and the second end edge 6B of the flexible strip 6 and the metal strip 7 is improved.

[0059] In the description of the first embodiment above, an example was described in which the two crimping structures present in the metal strip are substantially the same. However, it is not necessary to use the same crimping structure in both locations, and different crimping structures may be used. For example, one crimping section may use the crimping / sealing structure described in the first or second embodiment, while the other crimping section may be joined using a conventional crimping structure.

[0060] Furthermore, the applications of flexible hoses are not particularly limited. They can be used in air conditioning ducts, pipes for supplying hot air, exhaust ducts for internal combustion engines and combustion devices, flexible hoses for supplying liquids, powders, and granules, and cable sheathing components used inside buildings. [Industrial applicability]

[0061] The above-mentioned flexible hose can be used in ventilation ducts and other applications, and has high industrial value. [Explanation of Symbols]

[0062] 1. Flexible hose 2 Flexible strip 2A 1st edge 2B Second edge 21 First Turning Point 22 Second Turning Point 3. Metal strip 31 First turnaround section 31a End of the first folded section 32 Second Turning Point 32a End of the second folded section 33 Inner circumference 33a Projection 33b 1st flat plate part 33c 2nd flat plate part

Claims

1. A flexible hose (1) is formed by winding a flexible strip (2) of a predetermined width in a spiral shape while forming a predetermined folded shape, and crimping and joining the ends of adjacent flexible strips (2) with a metal strip (3), In the crimped joint, The flexible strip (2) is provided with a first folded portion (21) of the flexible strip that is folded back toward the inside of the hose and toward the center of the flexible strip. The aforementioned metal strip (3) is provided with a first folded portion (31) of the metal strip that is folded back toward the outside of the hose and toward the center of the metal strip. The aforementioned metal strip (3) has an inner circumference (33) that faces the inside of the hose, The inner circumference (33) has a first flat plate portion (33b) and a second flat plate portion (33c) extending parallel to the central axis of the hose, and a protruding portion (33a) provided between the first flat plate portion (33b) and the second flat plate portion (33c) so as to protrude outward from the hose. The width of the protruding portion is 1 / 5 or more and 3 / 5 or less of the width of the inner circumference portion (33). With the end portion (31a) of the first folded portion (31) of the metal strip positioned inside the first folded portion (21) of the flexible strip, the first folded portion (31) of the metal strip is crimped, and the flexible strip is sandwiched between the end portion (31a) of the first folded portion (31) of the metal strip and the protruding portion (33a) of the metal strip. Flexible hose (1).

2. The flexible strip (2) is provided with a second flexible strip (22) on the side edge opposite to the first flexible strip (21), which is folded back toward the inside of the hose and toward the center of the flexible strip. The metal strip (3) is provided with a second metal strip folded portion (32) on the side edge opposite to the first metal strip folded portion (31), which is folded back toward the outside of the hose and toward the center of the metal strip. With the end portion (32a) of the second folded portion (32) of the metal strip positioned inside the second folded portion (22) of the flexible strip, the second folded portion (32) of the metal strip is crimped, and the flexible strip is sandwiched between the end portion (32a) of the second folded portion (32) of the metal strip and the protruding portion (33a) of the metal strip. The flexible hose according to claim 1.

3. In the inner circumference (33) of the metal strip (3), the first flat plate portion (33b) and the second flat plate portion (33c) are located on the same cylindrical surface. The flexible hose according to claim 1 or claim 2.

4. A method for manufacturing a flexible hose according to Claim 1, The process includes a step of forming a protruding portion (33a) in the center of a flat metal strip in the width direction of the strip, The process includes a first crimping step, in which, after the rib formation step, the end portion (31a) of the first folded portion (31) of the metal strip is crimped so that it is positioned inside the first folded portion (21) of the flexible strip, thereby sandwiching the flexible strip between the end portion (31a) of the first folded portion (31) of the metal strip and the rib portion (33a) of the metal strip. A method for manufacturing a flexible hose.

5. A flexible hose (5) is formed by winding a flexible strip (6) of a predetermined width in a spiral shape while forming a predetermined folded shape, and crimping and joining the ends of adjacent flexible strips (6) with a metal strip (7), In the crimped joint, The aforementioned flexible strip (6) is provided with a first flexible strip folded portion (61) that is folded back toward the outside of the hose and toward the center of the flexible strip. The aforementioned metal strip (7) is provided with a first folded portion (71) of the metal strip that is folded back towards the center of the metal strip on the inside of the hose. The aforementioned metal strip (7) has an outer circumference (73) that faces the outside of the hose, The outer periphery (73) has a first flat plate portion (73b) and a second flat plate portion (73c) extending parallel to the central axis of the hose, and a protruding portion (73a) provided between the first flat plate portion and the second flat plate portion so as to protrude inward from the hose. The width of the protruding portion (73a) is 1 / 5 or more and 3 / 5 or less of the width of the outer peripheral portion (73). With the end portion (71a) of the first folded portion (71) of the metal strip positioned inside the first folded portion (61) of the flexible strip, the first folded portion (71) of the metal strip is crimped, and the flexible strip (6) is sandwiched between the end portion (71a) of the first folded portion (71a) of the metal strip and the protruding portion (73a) of the metal strip. Flexible hose (5).

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