JP2008224011A - End diameter expanded hose and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To uniformly form a diameter expanded portion of each end by preventing an extruded product from having an axial positional deviation when an diameter expanding mold is forcibly inserted into each end of the extruded portion axially to diameter-expand the each end, and an end diameter expanded hose having diameter expanded portion at both ends is formed. <P>SOLUTION: The end diameter expanded hose 10 has a rubber inner layer 16 and an rubber outer layer 20, and a reinforced layer 18 between them. The diameter expanded portion 30 is formed into a diameter expanding shape for a main part 32 having the end at a central side together with the inside diameter and the outside diameter. A recess part 36 having such a shape of being recessed to the axis side is partially and axially formed in the outer surface of the main part 32. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a high pressure resistant vibration absorbing hose, and more particularly to an end diameter-expanding hose suitable for being applied to piping in an engine room of an automobile and a method for manufacturing the same.

Conventionally, hoses mainly composed of a rubber layer have been widely used in various applications as industrial and automotive hoses.
The main purpose of using such a hose is to absorb vibrations.
For example, in the case of a piping hose disposed in an engine room of an automobile, the engine vibration, the compressor vibration of an air conditioner (in the case of a refrigerant transport hose, that is, an air conditioner hose), and various vibrations generated as the vehicle travels And is responsible for suppressing vibrations from being transmitted from one member connected through a hose to the other member.

  By the way, the structure of oil system, fuel system, water system, refrigerant system hose regardless of industrial use and automobile use is, for example, a reinforcing thread (reinforcing wire rod) between a rubber inner layer and a rubber outer layer as disclosed in Patent Document 1 below. ).

FIG. 18 (a) shows the structure of a refrigerant transport hose (air conditioner hose) disclosed in the following Patent Document 1, in which 200 is a rubber inner layer whose inner surface is covered with a resin inner surface layer 202. FIG. Yes.
A first reinforcing layer 204 is formed by spirally winding a reinforcing thread on the outer side of the rubber inner layer 200, and further, a reinforcing thread is spirally wound on the outer side via an intermediate rubber layer 206 in a direction opposite to the first reinforcing layer 204. The second reinforcing layer 208 is laminated, and the rubber outer layer 210 is laminated as the outermost cover layer.

This example is an example in which a reinforcing layer is formed by spiral braiding reinforcing yarn, but such a reinforcing layer is also formed by braiding a reinforcing yarn with a blade.
FIG. 18B shows an example thereof. In the figure, reference numeral 212 denotes a reinforcing layer formed by braiding reinforcing yarns between the rubber inner layer 200 and the rubber outer layer 210.
The inner surface of the rubber inner layer 200 is covered with a resin inner surface layer 202.

By the way, in the case of such a straight tubular hose, conventionally, a predetermined length has been required to ensure good vibration absorption.
Especially in high pressure resistant hoses such as oil systems (for example, power steering hoses) and refrigerant systems (refrigerant transport hoses) compared to low pressure hoses such as fuel systems and water systems, vibration absorption and The required length for reducing the propagation of sound and vibration into the passenger compartment is increased.
For example, in the case of a refrigerant transport hose, even if the linear distance to be connected is 200 mm, generally, a hose having a length of 300 to 600 mm is used to absorb vibration and reduce propagation of sound and vibration. .

  However, various devices and components are incorporated in the engine room, and in recent years, the engine room has become increasingly compact, and it is arranged there. If the hose length is long, piping design to avoid interference with other parts and handling when installing the hose will be a difficult task, and the piping design and handling for each vehicle type must be devised. It was a burden.

For this reason, development of a hose that has a short hose length and can absorb vibrations satisfactorily has been demanded.
As a means for shortening the length of the hose while ensuring vibration absorption in the hose, it is conceivable to make the hose into a bellows shape.

However, when the hose is formed into a bellows shape, the flexibility is dramatically improved. However, when a high fluid pressure acts on the inside of the hose, the entire hose greatly extends in the axial direction.
In this case, when both ends of the hose are in a fixed state (usually), the entire hose is bent greatly, causing a problem of causing interference with surrounding components.
In other words, it cannot be said that the countermeasure by the bellows shape is sufficient.

By the way, in the case of a high pressure hose such as an air conditioner hose, when the fluid is guided at a high pressure inside, the hose and the fluid are integrated and the behavior is closer to a rigid body than when no such pressure is applied. Will come to show.
The degree of rigidity increases as the cross-sectional area including the hose and fluid increases.
Conversely, if the cross-sectional areas of the hose and the fluid are reduced, the degree of rigidity is reduced, and the vibration absorption performance is increased accordingly.
Therefore, it is an effective means to reduce the hose diameter in order to increase the vibration absorption performance without shortening the hose into a bellows shape.

  However, if the entire hose including the axial end is made thinner and the fitting is made smaller in diameter, the inner diameter of the insert pipe in the fitting becomes smaller, and pressure loss (pressure Loss) and the required flow rate cannot be secured.

On the other hand, if a large-diameter fitting having an insert pipe with a large inner diameter is used after narrowing the caulked portion at the end, the insertion resistance is remarkably reduced when the insert pipe is inserted into the caulked portion at the end. It becomes large and the insertability of the insert pipe deteriorates, so it is practically difficult to attach the fitting.
Therefore, even if the hose diameter is reduced, it is desirable to keep the caulking portion of the end portion as it is, and to reduce the diameter of only the other main portion, that is, the main portion on the center side. Relative diameter expansion).

Therefore, the present inventors have devised an end diameter-expanding hose in which the end portion has a diameter-enlarged shape and the main portion on the center side has a small diameter. This is proposed in Patent Document 2).
FIG. 19 shows a specific example of the end diameter enlarged hose.
In FIG. 19, reference numeral 214 denotes an end diameter enlarged hose, which has a laminated structure of a rubber inner layer 216, an outer reinforcing layer 218, and an outermost rubber outer layer 220.
Reference numeral 222 denotes a diameter-enlarged portion provided at each end, which has an enlarged inner diameter and an outer diameter. Reference numeral 224 denotes a main portion on the center side between the pair of left and right enlarged diameter portions 222 in the drawing.
In the drawing, the outer diameter D ₁ and the inner diameter D ₂ of the enlarged diameter portion 222 are both larger than the outer diameters d ₁ and d ₂ of the main portion 224.

FIG. 20 shows a specific method for expanding the diameter of the end portion of the hose and forming the expanded diameter portion 222.
In the figure, reference numeral 226 denotes a cylindrical restraining tool that is externally fitted to and holds the main portion 224, and 228 is an enlarged type having an outer diameter corresponding to the inner diameter of the enlarged diameter portion 222.
In the method shown in FIG. 20, an extruded product 214 </ b> A in a semi-vulcanized state, which is extruded with a laminated structure of a rubber inner layer 216, a reinforcing layer 218, and a rubber outer layer 220 and cut to a predetermined size, is restrained in the main portion 224. (I), and in this state, the enlarged diameter mold 228 is forcibly pushed axially into the inside of the end of the extruded product 214A so that the end corresponds to the enlarged diameter mold 228. (II).
In this state, the extrusion-molded product 214A is heated in a vulcanizing can together with the restraining tool 226 and the diameter-expanding die 228 to vulcanize the extrusion-molded product 214A, and the end-diameter expanded hose 214 shown in FIG. 19 is manufactured. To do.

However, it has been found that the following problems occur when the end portion of the extruded product 214A is expanded and deformed by the method shown in FIG.
That is, when the diameter-expanding die 228 is inserted into the end portion of the extrusion-molded product 214A, it cannot always be inserted well, and the diameter-expansion die 228 is strongly attached to the end portion of the extrusion-molded product 214A in the axial direction. When pushed, the rubber layer of the extruded product 214A is moved in the axial direction together with the diameter-expanding die 228, that is, the end portion is compressed in the axial direction and the rubber inner layer 216 is moved in the axial direction as shown in FIG. It has been found that the problem is that the wrinkles 230 as shown in III) occur on the inner surface.

  In particular, in the case of a high-pressure high-pressure hose having a burst pressure of 5 MPa or more and a braid density of the reinforcing layer of 50% or more, a large resistance is generated due to the presence of the reinforcing layer 218 when the diameter-expanding die 228 is pushed in, When the diameter-expanding die 228 is strongly pressed in the axial direction against such resistance, the end of the extruded product 214A is compressed in the axial direction along with the strong pressing, and the compression of the rubber inner layer 216 is caused by the compression. A part of the portion protrudes radially inward to easily generate the above-described ridges 230.

Further, the diameter of the end portion of the extruded product 214A using the above-described diameter-expanding die 228 is increased by pushing the pair of diameter-expanding dies 228 in opposite directions at each end of the extrusion-molded product 214A. The push-in timing of the diameter-expanding mold 228 is not exactly the same, and a slight push-in timing difference occurs.
In this case, if the holding force by the restraining tool 226 is weak, the extruded product 214A is displaced in the axial direction due to the pushing force of the diameter-expanding die 228 on the side pushed in at an early timing, and a pair of diameter-expanding at each end. It has also been found that there is a problem that it is difficult to form the enlarged diameter portion 222 with the mold 228 well.

  In the case of the method shown in FIG. 20, the inner surface of the enlarged diameter portion 222 can be formed by the enlarged diameter mold 228 and the inner diameter can be regulated, but the outer surface of the enlarged diameter portion 222 and the inner surface and the outer surface of the main portion 224. Since the molding is not performed with a molding die, the surfaces cannot be molded well, the inner diameter and the outer diameter cannot be regulated, and the diameter-expanding mold is not performed without regulating the inner diameter and the outer diameter. In order to push 228 in the axial direction with respect to the end portion, the end portion is easily compressed in the axial direction by a part of the rubber escaping in the radial direction. It is also a cause that is likely to occur on the inner surface and the outer surface.

Japanese Patent Laid-Open No. 7-68659 JP 2006-238443 A

The present invention has been made against the background as described above, and can prevent the positional deviation of the extruded product in producing the end diameter expanded hose, and therefore, when molding the expanded diameter section at each end, It is an object to make it possible to form the diameter-expanded portion of each end portion satisfactorily.
Another object of the present invention is to satisfactorily prevent generation of wrinkles on the inner surface of the root of the enlarged diameter portion.
Still another object of the present invention is to provide an end-expanded hose capable of forming the inner and outer surfaces satisfactorily and having high accuracy in the dimensions of the inner and outer diameters when manufacturing the end-expanded hose. .

  Thus, claim 1 relates to an end diameter-expanded hose having a laminated structure having a rubber inner layer and a rubber outer layer and a reinforcing layer formed by braiding reinforcing wires interposed between them, and each end portion being a center. The inner diameter and the outer diameter of the main part on the side are enlarged diameter parts, and the rigid insert pipe inserted into the enlarged diameter part and the outer diameter of the enlarged diameter part are fitted into the reduced diameter direction. A joint tool having a socket fitting that is caulked is an end diameter-expanding hose to be attached to the diameter-expanded part, and a concave part having a shape recessed on the axial center side on the outer surface of the main part is partially in the axial direction. It is provided.

  The invention according to claim 2 comprises a laminated structure having a reinforcing layer formed by braiding reinforcing wire rods interposed between the rubber inner layer and the rubber outer layer, and each end has an inner diameter with respect to the main portion on the center side, A joint having an enlarged diameter portion that has an enlarged diameter on both outer diameters, and a rigid insert pipe that is inserted into the enlarged diameter portion and a socket fitting that is externally fitted to the enlarged diameter portion and caulked in the reduced diameter direction. The tool is an end diameter-enhancing hose to be mounted on the diameter-enlarged portion, wherein a concave portion having a shape recessed toward the axial center is provided on the outer surface of the diameter-enlarged portion.

  According to a third aspect of the present invention, in the first aspect of the present invention, the concave portion is provided in a form continuously extending over the entire circumference in the circumferential direction along the outer surface of the main portion.

  According to a fourth aspect of the present invention, in the first aspect, the concave portion is provided at a plurality of positions in the axial direction.

  According to a fifth aspect of the present invention, in the first aspect of the present invention, the concave portion has a shape extending in the axial direction, and is provided partially in the circumferential direction and at a plurality of locations in the circumferential direction.

  According to a sixth aspect of the present invention, in the first aspect of the present invention, the concave portions are arranged at a predetermined pitch in the axial direction so that the axial cross-sectional shape of the outer surface of the main portion is a continuous serrated irregular shape. It is characterized by.

  According to a seventh aspect of the present invention, in the second aspect of the present invention, the concave portion is provided in a form that continuously extends in the circumferential direction along the outer surface of the enlarged diameter portion.

  According to an eighth aspect of the present invention, in the second aspect, the concave portion is partially provided in the axial direction.

  According to a ninth aspect of the present invention, in the second aspect, a plurality of the concave portions are provided side by side in the axial direction.

  According to a tenth aspect of the present invention, in the ninth aspect, the concave portions are arranged side by side at a predetermined pitch in the axial direction so that the axial cross-sectional shape of the outer surface of the enlarged diameter portion is a continuous serrated irregular shape. It is characterized by that.

  An eleventh aspect of the present invention relates to a method for manufacturing the end-diameter expanded hose according to the first aspect. The manufacturing method includes: (a) a main portion provided with a convex-shaped portion corresponding to the concave portion for forming the outer surface of the main portion; A molded surface having a shape corresponding to the outer shape of the end diameter enlarged hose, and a shaft formed on the inner side of the molded surface. An outer mold having a molding recess penetrating in the direction, and (b) a mandrel that molds the inner surface of the main part of the end diameter-enhanced hose, and obtained by extrusion molding, the rubber inner layer, the rubber outer layer, and The mandrel is inserted into an unvulcanized or semi-cured straight tubular extruded product having a reinforcing layer, and the extruded product is inserted and set in the molding recess of the outer mold together with the mandrel. Then, a fitting hole that slidably fits on the mandrel. Is formed in a shape corresponding to the inner surface of the enlarged-diameter portion, and has a diameter-enlarged mold having an enlarged-surface forming surface for forming the inner surface of the enlarged-diameter portion on the outer surface. The end is expanded by inserting it axially along the mandrel into the inside, the inner surface of the end is molded with the diameter-enlarging mold, and the outer surface is molded with the outer mold. Heating together with the outer mold, the mandrel, and the diameter-expanding mold to completely vulcanize.

  The twelfth aspect relates to a method for manufacturing the end diameter-enhanced hose according to the second aspect. The manufacturing method includes (a) molding a main part molding surface for molding the outer surface of the main part and an outer surface of the enlarged diameter part. A molding surface having a shape corresponding to the outer shape of the end-diameter enlarged hose, and a shaft formed on the inner side of the molding surface. An outer mold having a molding recess penetrating in the direction, and (b) a mandrel that molds the inner surface of the main part of the end-diameter expanded hose, and obtained by extrusion molding, the rubber inner layer, the rubber outer layer, and A state in which the mandrel is inserted into an unvulcanized or semi-cured straight tubular extruded product having a reinforcing layer, and the extruded product is inserted and set in the molding recess of the outer mold together with the mandrel. After that, the fitting hole is slidably fitted into the mandrel. Is formed in a shape corresponding to the inner surface of the enlarged-diameter portion, and has a diameter-enlarged mold having an enlarged-surface forming surface for forming the inner surface of the enlarged-diameter portion on the outer surface. The end is expanded by inserting it axially along the mandrel into the inside, the inner surface of the end is molded with the diameter-enlarging mold, and the outer surface is molded with the outer mold. Heating together with the outer mold, the mandrel, and the diameter-expanding mold to completely vulcanize.

Effects and effects of the invention

As described above, according to the first aspect of the present invention, the outer surface of the main portion of the end diameter-expanded hose is partially provided with a concave portion having a shape recessed toward the axial center side in the axial direction.
By providing such a concave portion on the outer surface of the main part, each end of the extruded product is strongly restrained in the axial direction by the corresponding convex shape part of the outer mold that restrains the outer surface of the main part. The diameter-expanded part can be pushed in the opposite direction to form the diameter-expanded part. At that time, even if the timing of pressing the diameter-expanded mold is shifted at each end, the extruded product is in the axial direction. Therefore, it is possible to effectively prevent the misalignment, and it is possible to satisfactorily mold the diameter-enlarged portion of each end portion with the intended shape.

On the other hand, according to the second aspect of the present invention, a recess having a shape recessed toward the axial center is provided on the outer surface of the enlarged diameter portion.
According to the second aspect of the present invention, when the enlarged-diameter mold is pushed into the end portion of the extruded product in the axial direction by the convex portion of the outer mold corresponding to the concave portion of the enlarged-diameter portion, the end portion moves in the axial direction. It is possible to effectively prevent the generation of wrinkles along with the compression.

According to claim 1, the concave portion can be provided in a form continuously extending along the outer surface of the main portion in the circumferential direction along the outer surface according to claim 3, and according to claim 4, a plurality of axial portions can be provided. Can be provided.
Further, according to the fifth aspect, the concave portion can be provided in a portion extending in the circumferential direction in a shape extending in the axial direction and at a plurality of locations in the circumferential direction.
However, in this case, it is desirable to provide the recesses at equal intervals in the circumferential direction.

According to a sixth aspect of the present invention, the recesses can be provided side by side at a predetermined pitch in the axial direction so that the axial cross-sectional shape of the outer surface of the main part is a continuous serrated uneven shape.
The claim 1, in any one of claims 3 to 5, when the depth of the recess of the rubber outer layer in the main portion was set to t _1, it is desirable to provide a depth of 0.1 t ₁ ~t _1.
If the depth of the recess is less than 0.1 t ₁ , the effect of providing the recess is not sufficiently obtained. Conversely, if the depth of the recess is deeper than t ₁ , rubber burrs are generated on the outer surface during molding. Or the lower reinforcing layer of the rubber outer layer may be damaged by the convex portion of the outer mold.

  Next, in claim 2, the concave portion can be provided in a form continuously extending along the outer surface of the enlarged diameter portion in the circumferential direction over the entire circumference according to claim 7, and the concave portion according to claim 8. It can be partially provided in the axial direction.

Furthermore, according to claim 9, a plurality of such recesses can be arranged in the axial direction.
In this case, the concave portions can be arranged in a predetermined pitch in the axial direction so that the axial cross-sectional shape of the outer surface of the enlarged diameter portion is a continuous serrated irregular shape.

The second aspect, in any one of claims 7 to 10, that the depth of the recess to keep the depth of the range of the thickness of the rubber outer layer in the enlarged diameter portion of 0.1 t ₂ ~t ₂ as t ₂ desirable.
If the depth of the recess is less than 0.1 t ₂ , the effect of providing the recess is not sufficiently obtained. Conversely, if the depth of the recess is greater than t ₂ , rubber burrs are generated on the outer surface during molding. Or the lower reinforcing layer of the rubber outer layer may be damaged by the convex portion of the outer mold.

  Next, an eleventh aspect relates to a method of manufacturing the end-diameter expanded hose of the first aspect. The manufacturing method includes a mandrel that molds the inner surface of the main portion and a convex that corresponds to the concave portion that molds the outer surface. An end-expanded hose is formed using an outer mold having a shape portion and a diameter-expanding mold that is pushed into the inside of the end portion of the extruded product to expand the diameter thereof, and vulcanized in the molded state. Thus, according to the eleventh aspect, when the diameter-expanding die is pushed into the end portion of the extrusion-molded product, it is possible to satisfactorily prevent the extrusion-molded product from being displaced in the axial direction with respect to the outer mold. The inner and outer surfaces of the end-expanded hose can be molded with good surface properties, and the inner and outer diameters can be well controlled by the mandrel, diameter-expanding die and outer die. An end-expanded hose with a high dimensional system can be obtained.

  Next, a twelfth aspect of the present invention is to provide an end diameter-enhanced hose using a mandrel that molds the inner surface of the hose main part, an outer mold that includes a convex-shaped part that forms a recess on the outer surface of the expanded diameter part, and a diameter-expanded mold And is vulcanized in the molded state. According to the manufacturing method of claim 12, it is possible to satisfactorily prevent the generation of wrinkles on the inner surface of the root of the enlarged diameter portion, and the mandrel. The inner and outer surfaces of the end-expanded hose can be molded with good surface properties by the expanded-diameter and outer mold, and the inner and outer diameters can be regulated. It can be manufactured.

Next, embodiments of the present invention will be described in detail with reference to the drawings.
In FIG. 1, 10 is a high pressure vibration absorbing hose (hereinafter simply referred to as a hose) used as, for example, a refrigerant transport hose (air conditioner hose), and 12 is a joint fitting fixed by caulking to each end of the hose 10. (Joint tool).
Reference numeral 14 denotes a cap nut that is rotatably attached to the fitting 12 and more specifically to an insert pipe 22 described later.

As shown in FIG. 1B, the hose 10 includes a rubber inner layer 16, a reinforcing layer 18 formed by braiding a reinforcing yarn (reinforcing wire) on the outer side thereof, and a rubber outer layer 20 as an outermost cover layer. And has a laminated structure.
In this embodiment, the hose 10 has a braid density in the reinforcing layer 18 of 80% or more and has a pressure resistance (burst pressure) of 10 MPa or more.

  Here, PET, PEN, aramid, PA (polyamide), vinylon, rayon, or the like can be used as the reinforcing yarn constituting the reinforcing layer 18.

Further, as the rubber inner layer 16, a single material or a blend material such as IIR, halogenated-IIR (Cl-IIR, Br-IIR), NBR, CR, EPDM, EPM, FKM, ECO, silicon rubber, urethane rubber, acrylic rubber or the like is used. be able to.
However, in the case of an HFC refrigerant transport hose, an IIR or halogenated-IIR single material or a blend material is particularly preferable.

  In addition, various rubber materials enumerated in the rubber inner layer 16 can be used as the rubber outer layer 20, but heat shrinkable tubes and thermoplastic elastomers (TPE) can also be used. Styrene, olefin, diolefin, vinyl chloride, urethane, ester, amide, fluorine, and the like can be used.

As shown in FIG. 2, the joint fitting 12 has a metal-made rigid insert pipe 22 and a sleeve-like socket fitting 24. 30, and the socket metal fitting 24 is fitted to the outer surface of the enlarged diameter portion 30 and caulked in the reduced diameter direction, so that the enlarged diameter portion 30 is moved inward and outward by the insert pipe 22 and the socket metal fitting 24. The hose 10 is caulked and fixed in a state of being pinched between the two.
Here, the socket metal fitting 24 is provided with an inwardly-shaped annular hook-shaped portion 26, and the inner peripheral end of the hook-shaped portion 26 is locked in an annular locking groove 28 on the outer peripheral surface of the insert pipe 22. It is fixed by caulking to the state.

FIG. 3 shows the shape of the hose 10 before the fitting 12 is caulked.
As shown in the drawing, the hose 10 has a diameter-expanded portion 30 whose both end portions have a diameter-expanded shape (inner diameter expansion rate of 40% or more), and a central portion between the diameter-expanded portions 30 and 30. Constitutes a main part 32.
Here, the inner diameter expansion ratio is a ratio of the difference between the inner diameter after the expansion and the inner diameter before the expansion to the inner diameter before the expansion.
Reference numeral 34 denotes a tapered transition portion formed between the enlarged diameter portion 30 and the main portion 32.
Here, in the enlarged diameter portion 30, the outer diameter D ₁ and the inner diameter D ₂ are both larger than the outer diameter d ₁ and the inner diameter d _{2 of the} main portion 32, respectively.
That is, in this type of conventional hose, the outer diameter of the main portion 32 is the same as the outer diameter of the end portion, but in the hose 10 of this example, only the main portion 32 has a small diameter shape. Yes.
In the present embodiment, as shown in FIG. 2, the inner diameter d ₂ of the insert pipe 22 of the fitting 12 inserted into the enlarged diameter portion 30 is the same as the inner diameter of the main portion 32.

In the present embodiment, as shown in FIG. 3, the outer surface of the central portion of the main portion 32 is provided with a recess 36 having a shape recessed toward the axial center side (inward in the radial direction).
Here, the concave portion 36 is provided over a predetermined length in the axial direction, and the shape thereof is an annular shape that is continuous over the entire circumference in the circumferential direction of the main portion 32.
Here, in the recess 36, the depth A shown in the partially enlarged view of FIG. 3 is 0.1 to 0.5 mm (the total depth on both sides in the radial direction is 0.2 to 1.0 mm). Depth).

However, this is merely an example, when the thickness of the rubber outer layer 20 of the main portion 32 and t _1, the depth A of the recess 36 be properly determined depth in the range of 0.1 t ₁ ~t ₁ it is (hence main portion 32 has an outer diameter of the outer diameter in the range of _{d 1 -0.2t} 1 _~d 1 -2t 1 at the site where a recess 36).
Effect depth is to the provision of the less the recess 36 than 0.1 t ₁ of the concave portion 36 is not sufficiently obtained, and when the depth is greater than t _1, the hose 10 as revealed after During manufacture, there is a risk that an external rubber burr will be generated or the reinforcing layer 18 will be damaged.

In this embodiment, tapered portions 38 are provided at both axial ends of the recess 36. And the recessed part 36 is provided by the axial length B in the distance between the root positions inside these taper parts 38 inside each other.
The dimension B is selected here as a length in the range of 5 (mm) to 0.8 L (mm) where L is the total length of the main portion 32 (see FIG. 3).
However, generally, the axial length B of the recess 36 can be appropriately selected with a dimension of 0.8 L or less.

If the axial length B of the concave portion 36 is smaller than 5, the effect of providing the concave portion 36 is not sufficiently obtained. Conversely, if the axial length B is larger than 0.8 L, an outer surface rubber burr (each divided mold 52 of the outer die 46 described later). Burrs caused by the rubber entering the split surfaces are likely to occur.
As will be described later, the recess 36 can be provided partially in a plurality of locations in the axial direction of the main portion 32. Even in this case, it is desirable that the total length in the axial direction of the plurality of recesses be 0.8 L or less.

Here, the inclination angle θ of the taper portion 38 is within a range of 7 to 90 ° or less.
Further, it is desirable to perform edge processing on the corner portion 40 in the partially enlarged view of FIG. Specifically, it is desirable that R processing is performed with respect to the depth A of the concave portion 36 so that each corner portion 40 has an arc surface with a curvature radius R of 0.2 mm to A / 2 mm.

In the present embodiment, as shown in FIG. 3, a large number of recesses 42 are provided on the outer surface of the enlarged diameter portion 30 over the entire length in the axial direction and over the entire surface.
Here, each recessed part 42 is provided in the form extended annularly continuously over the perimeter along the outer surface of the enlarged diameter part 30 in the circumferential direction.
Here, the respective recesses 42 may have an annular shape independent of each other in the axial direction, or may be provided in a continuous annular shape that spirals in the axial direction.

In this embodiment, the recesses 42 are provided in parallel in the axial direction, and the axial cross-sectional shape of the outer surface of the enlarged diameter portion 30 is formed in a small pitch at a constant pitch so as to be a continuous serrated irregular shape. They are arranged side by side.
However, the recesses 42 can be provided so that the pitch in the axial direction is all constant, or can be provided so that the pitch changes little by little.

In this embodiment, each recessed part 42 is provided in the shape which makes the convex part 44 formed between them a cross-sectional mountain shape. That is, the concave portion 42 is provided between the adjacent convex portions 44 of the mountain shape so as to form a valley shape having a corresponding shape.
Here, the concave portion 42 is provided so as to have an isosceles triangular cross section, but the sectional shape of the concave portion 42 may be various other shapes as will be described later.

As described later, the concave portion 42 in the enlarged diameter portion 30 moves the end portion of the extruded product 10A in the axial direction by the convex portion 66 in the outer die 46 when the enlarged diameter die 50 is pushed in the axial direction. Therefore, in order to effectively prevent the movement, it is desirable to provide the concave portion 42 in a shape that is continuous over the entire circumference in the circumferential direction, and in the axial direction. It is desirable to provide a large number of the enlarged diameter portions 30 in a state where they are arranged in parallel at a constant pitch.
However, as will be described later, the concave portion 42 can be partially provided in the axial direction.

The depth of the recess 42, here is 10% of the depth of the wall thickness t ₂ of the rubber outer layer 20 of the enlarged diameter portion 30, but this is an example, the depth of such recesses 42 are generally rubber and the wall thickness _{t 2} of the outer layer 20 can be set to an appropriate depth in the range of 0.1 t ₂ ~t _2.
Recess depth of 42 0.1 t ₂ less the recess 42 the effect of the provision of the not sufficiently obtained than when conversely depth becomes larger than t _2, easily outer surface rubber burr is generated, Further, the reinforcing layer 18 is easily damaged.

The pitch of the recesses 42 in the axial direction is preferably set to a pitch within a range of W / 3 to 2W where the depth of the recesses 42 is W (the recesses 42 are aligned at a predetermined pitch in the axial direction). When providing in the state).
Further, it is desirable that the angle of the bottom of the concave portion 42, that is, the angle of the top portion of the convex-shaped portion 66, which will be described later, which forms the concave portion 42, is determined within a range of 10 to 90 °.

Further, in the present embodiment, the bottom of the concave portion 42 having a triangular cross section is an arc surface having a radius of curvature (R) within 50% of the depth W of the concave portion 42, that is, the bottom of the valley is such a curvature. R processing is performed, that is, the top portion of the convex portion 66 of the outer mold 46 to be described later forming the concave portion 42 is set as an arc surface having a radius of curvature (R) within 50% of the protruding height. Is desirable.
This is because if the mountain-shaped protruding portion 66 has a sharp edge shape, the outer surface of the enlarged diameter portion 30 may be damaged during molding, and the hose 10 may be broken starting from the damaged portion.

4 and 5 show a specific configuration of a forming apparatus used in manufacturing the hose 10 of the present embodiment.
In these drawings, reference numeral 45 denotes a molding apparatus. The molding apparatus 45 includes an outer mold 46, a mandrel 48 and a pair of diameter-expanding molds 50.
In this embodiment, the outer mold 46 has a vertically divided structure in the drawing. In the figure, 52 indicates the division type.

The outer mold 46 includes a molding surface 54 having a shape corresponding to the outer shape of the hose 10, and a molding recess 56 that is formed on the inner side and penetrates in the axial direction.
The molding surface 54 includes a main part molding surface 58 that molds the outer surface of the main part 32 of the hose 10, and an enlarged-diameter part molding surface 60 that molds the outer surface of the enlarged-diameter part 30.

Here, the main portion molding surface 58 has a shape corresponding to the outer surface of the main portion 32 in the hose 10, and the inner diameter thereof is an inner diameter corresponding to the outer diameter d ₁ of the main portion 32. The part molding surface 60 has a shape corresponding to the outer surface of the enlarged diameter portion 30 in the hose 10, and the inner diameter thereof is the inner diameter corresponding to the outer diameter D ₁ of the enlarged diameter portion 30.
The molding surface 54 is provided with a tapered transition portion 61 having a shape corresponding to the tapered transition portion 34 of the hose 10.

As shown in FIG. 6, the main portion molding surface 58 is provided with a convex portion 62 having a shape corresponding to the concave portion 36 of the main portion 32 of the hose 10 so as to protrude radially inward.
The convex portion 62 is a portion for forming the concave portion 36 of the main portion 32 in the hose 10, and is provided with a cross-sectional shape corresponding to the concave portion 36. In FIG. 6, reference numeral 64 denotes a tapered portion provided in a shape corresponding to the tapered portion 38 (see FIG. 3) provided on both axial sides of the concave portion 36.
Here, the convex shaped portion 62 has an inner surface that is smooth in the axial direction corresponding to the shape of the concave portion 36. The convex portion 62 is provided in an annular shape that is continuous in the circumferential direction.

On the other hand, as shown in FIG. 6, the enlarged diameter portion molding surface 60 has a shape corresponding to the concave portion 42 of the enlarged diameter portion 30 in the hose 10 over the entire axial length and the entire circumference of the enlarged diameter portion molding surface 60. A convex portion 66 is provided.
As shown in FIG. 6, the convex portion 66 is formed in a cross-sectional mountain shape corresponding to the shape of the concave portion 42 in FIG. 3, and has an annular shape continuous over the entire circumference, and It is provided in a state of being arranged in parallel at a constant pitch in the axial direction (in a state of being parallel).
As described above, each of the convex portions 66 may have an annular shape that is independent in the axial direction, or may be a spiral convex portion that extends continuously in the axial direction.
As shown in FIG. 7, one split mold 52 is provided with a positioning protrusion 86, and the other split mold 52 is correspondingly positioned with a positioning hole 88 into which the positioning protrusion 86 is fitted. Is provided.

The mandrel 48 has a main portion 68 having a circular cross section and a smooth surface in the axial direction, and male screw portions 70 at both ends.
Here, the main portion 68 is a portion that molds the inner surface of the small main portion 32 in the hose 10, has a shape corresponding to the inner surface of the main portion 32 in the hose 10, and the outer diameter is the inner diameter of the main portion 32. It is an outer diameter corresponding with d _2.
Note that the axial length of the main portion 68 is longer than the axial lengths of the hose 10 and the outer mold 46.

The diameter-expanding die 50 has an axially penetrating fitting hole 72 slidably fitted to the main portion 68 of the mandrel 48 with a small clearance, and the outer surface has an enlarged portion. A diameter-enlarged portion molding surface 74 for molding the inner surface of the diameter portion 30 is provided.
The diameter-expanding die 50 is also provided with a tapered portion 76 for forming the inner surface of the tapered transition portion 34 in the hose 10 at the position adjacent to the diameter-expanded portion forming surface 74 on the outer surface, and the diameter-expanded portion. A taper portion 78 is provided at a position opposite to the taper portion 76 with respect to the molding surface 74, and a large-diameter flange portion 80 is provided adjacent thereto.
Here, an inner surface (surface on the outer mold 46 side) 82 of the flange portion 80 is a flat surface perpendicular to the axis.
Reference numeral 84 denotes a tightening nut that is screwed into the male threaded portion 70 at both ends of the mandrel 48, and the outer surface has a hexagonal shape.

Next, a method for manufacturing the hose 10 shown in FIGS. 1 to 3 using the molding apparatus shown in FIGS. 4 to 7 will be specifically described below based on FIGS. 8 to 10.
In the manufacturing method of the present embodiment, first, a straight tubular long hose having a laminated structure of the rubber inner layer 16, the reinforcing layer 18, and the rubber outer layer 20 is formed by extrusion, and then cut into predetermined dimensions, as shown in FIG. Then, the extruded product 10A in an unvulcanized state is first brought into a semi-vulcanized state. Alternatively, the extruded long hose is first semi-vulcanized and then cut into predetermined dimensions to obtain an extruded product 10A.

Then, the mandrel 48 is inserted into the extruded product 10 </ b> A, and the extruded product 10 </ b> A is inserted and set in the molding recess 56 of the outer mold 46 together with the mandrel 48.
Then, in a state where the outer mold 46 is tightened, in particular, in a state where the pair of split molds 52 are tightened in the mold-clamped state, the pair of diameter-expanding molds 50 are opposed to the mandrel 48 outside the outer mold 46 on opposite sides. And a pair of tightening nuts 84 are screwed onto the male threaded portion 70 of the mandrel 48 on the outer side of the diameter-expanding die 50 (FIGS. 9I and II). reference).
Then, by tightening the tightening nut 84, the pair of diameter-expanding dies 50 are axially pushed into the inside of the end portion of the extruded product 10A by a screw feeding action.
The pair of diameter-expanding dies 50 is pushed in simultaneously at each end of the extruded product 10A.

In the manufacturing method of the present embodiment, when the outer mold 46 is clamped together with the pair of split molds 52, the convex portion 62 provided at the center of the main molding surface 54 of the outer mold 46 is the extruded product 10A. The outer surface of the main part 32 is partially sandwiched in the radial direction so as to be partially compressed toward the axial center, and this is held.
The concave portion 36 in the hose 10 is formed by compressive deformation by the convex portion 62 at this time.
Accordingly, in this state, the extruded product 10A is prevented from being displaced in the axial direction with respect to the outer mold 46 as shown in the partially enlarged view of FIG.

In the extrusion molded product 10 </ b> A, each end portion in the axial direction is expanded radially outward by pushing the diameter-enlarging die 50, and the diameter-enlarged portion 30 is formed by the diameter-enlarging die 50 and the outer die 46. The
Specifically, the inner surface of the enlarged diameter portion 30 is molded by the enlarged diameter portion molding surface 74 of the enlarged diameter mold 50, and the outer surface of the enlarged diameter portion 30 is molded by the enlarged diameter portion molding surface 60 of the outer mold 46.
At this time, the convex portion 66 provided on the enlarged-diameter portion molding surface 60 of the outer mold 46 bites into the end of the extruded product 10A, that is, the outer surface of the enlarged-diameter portion 30, and compresses the enlarged-diameter portion 30 to the axial center side. It will be in the state.
The concave portion 42 of the enlarged diameter portion 30 in the hose 10 is formed by the biting of the convex portion 66 at this time.
At this time, due to the compression and biting action on the outer surface of the end portion of the extruded product 10 by the convex portion 66, the end portion moves in the axial direction together with the pressing of the diameter expanding die 50 when the diameter expanding die 50 is pushed in. Thus, the same portion is compressed in the axial direction, thereby effectively preventing the above-described wrinkles from being generated on the root inner surface of the enlarged diameter portion 30.

In this embodiment, when the diameter-expanding die 50 is pushed in, the tapered portion 78 on the large-diameter flange portion 80 side enters inside the shaft end of the extruded product 10A, that is, inside the shaft end of the diameter-expanded portion 30. In addition, the large-diameter flange portion 80 abuts against the axial end surface of the outer die 46 in a state where the enlarged die 50 is pushed.
FIG. 9 (III) shows the state at this time.
Then, as shown in FIG. 10, in this state, the molding device 45 is inserted into the vulcanization container together with the extruded product 10A, and the extruded product 10 is vulcanized over a predetermined time. That is, complete vulcanization is performed.

In this embodiment, the flange part 80 and the taper part 78 in the diameter expansion mold 50 have the following meanings.
That is, when the flange portion 80 abuts against the axial end surface of the outer mold 46, the molding recess 56 in the outer mold 46 is covered at both ends, and the molding recess 56 is a closed space.
Thus, during the vulcanization process shown in FIG. 10, it is possible to prevent a part of the rubber material of the extruded product 10 from protruding in the axial direction from the molding recess 56 due to expansion due to heating during vulcanization.
Further, the axial end surface of the hose 10 can be well formed by the surface 82 in the axially perpendicular direction inside the flange portion 80.

On the other hand, the taper portion 78 functions as follows.
That is, if such a taper portion 78 is not provided in the diameter expansion mold 50, the hose 10 obtained by vulcanization has an inner diameter required by the inner diameter of the opening side end of the diameter expansion portion 30 immediately after vulcanization. However, the phenomenon that the opening end contracts in the radial direction due to the shrinkage of the rubber material is caused thereafter, and the inner diameter of the opening end becomes smaller than the appropriate inner diameter to be obtained.
Therefore, in this embodiment, the tapered portion 78 is provided in the diameter-expanding die 50 so that the inner diameter on the opening end side of the diameter-expanded portion 30 is expanded from the inner diameter that is finally planned in advance during vulcanization molding. deep.
By doing in this way, when the opening end inner diameter of the enlarged diameter portion 30 is reduced after vulcanization, the inner diameter can be obtained.
Therefore, in this embodiment, the taper angle and the diameter of the taper portion 78 are determined to be a shape and a size so that the inner diameter on the opening end side of the enlarged diameter portion 30 is the required inner diameter after contraction.

  When the recessed part 36 is provided in the outer surface of the main part 32 in the edge part diameter expansion hose 10 like the above this embodiment, the state which restrained the whole outer surface of the main part 32 of 10 A of extrusion molded products with the outer mold | type 46 Thus, when the enlarged diameter mold 50 is pushed into each end in the opposite direction and the enlarged diameter portion 30 is formed, each end portion is pressed by the pressing action on the main portion 32 by the convex portion 62 of the outer mold 46 corresponding to the recessed portion 36. Thus, even when the timing of pushing in the enlarged mold 50 is shifted, it is possible to effectively prevent the extruded product 10A from being displaced in the axial direction with respect to the outer mold 46, and the enlarged section 30 at each end. Can be molded well in a desired shape.

  Further, since the concave portion 42 having a shape recessed toward the axial center side is provided on the outer surface of the enlarged diameter portion 30, the enlarged diameter die 50 is extruded by the convex shape portion 62 of the outer mold 46 corresponding to the concave portion 42 of the enlarged diameter portion 30. When the end of the molded product 10A is pushed in the axial direction, the end is moved and compressed in the axial direction, and generation of wrinkles along with the compression can be effectively prevented.

  Further, the end portion of the extruded product 10A is prevented from moving in the axial direction in this manner, so that the rubber layer moves in the axial direction and the pressure is partially increased. It is also possible to prevent a minute clearance (gap) between the first and second diameter-expanding molds 50 from entering a rubber burr.

In addition, according to the manufacturing method of the present embodiment, the inner and outer surfaces of the end diameter-expanded hose 10 can be formed with good surface properties by the mandrel 48, the diameter-expanding mold 50, and the outer mold 46, and the inner diameter and the outer diameter can be increased. The diameter can be regulated well, and the end-expanded hose 10 having a high inner / outer diameter system can be obtained.
Furthermore, wrinkles can be satisfactorily prevented from occurring on the inner surface of the root of the enlarged diameter portion 30.

Next, FIGS. 11 to 13 show other embodiments of the recess 36 in the main portion 32.
First, FIG. 11 shows an example in which the recess 36 is provided with a shorter axial length than that shown in FIG. In addition, as shown in the partial enlarged view of FIG. 11, each corner | angular part 40 of the recessed part 36 is edge-processed as a circular arc surface as mentioned above.
This also applies to the embodiments of FIGS. 12 and 13.
The outer mold 46 is provided with a convex portion 62 in a shape corresponding to the concave portion 36.

FIG. 12 shows an example in which a plurality of concave portions 36 having a short axial length are provided at predetermined intervals in the axial direction of the main portion 32.
On the other hand, the example of FIG. 13 is an example in which the main portion 32 of the hose 10 is partially provided with recesses 36 extending in the axial direction at a plurality of locations in the circumferential direction.
Here, the recess 36 has a substantially semicircular or arcuate cross-sectional shape, but this shape can be various other cross-sectional shapes.

In addition, here, the recesses 36 are provided at four locations separated by 90 degrees in the circumferential direction.
For this reason, when the convex part 62 is provided in the outer mold 46 in the corresponding shape and corresponding position, when the extruded product 10A is sandwiched between the outer mold 46 and the axial center side, the main part 32 is moved around the entire circumference. This can be pressed and held with a uniform force.
In the example of FIG. 13, the recesses 36 are provided at four locations in the circumferential direction, but it is of course possible to provide them at three locations or at multiple locations of five or more locations.
Even in this case, it is desirable to provide the recesses 36 at equal intervals in the circumferential direction.

On the other hand, in FIG. 14, the concave portion 42 in the main portion 32 is formed so that the axial cross-sectional shape of the outer surface of the main portion 32 is a continuous serrated uneven shape like the concave portion 42 in the enlarged diameter portion 30 in FIG. This is an example in which a large number are arranged side by side at a constant pitch in the axial direction.
Correspondingly, the outer mold 46 is provided with a convex portion 66 having a shape corresponding to the concave portion 42.
In FIG. 14, the cross-sectional shape of the recess 42 is an isosceles triangle, but it can be changed to various other cross-sectional shapes.

On the other hand, FIG. 15 shows another example of the concave portion 42 in the enlarged diameter portion 30 ((B) in the figure represents the concave portion 42 and (A) represents the shape of the convex portion 66 corresponding thereto. ).
In the above embodiment, the recess 42 is formed in an isosceles triangle shape in cross section, but the recess 42 may be provided in a triangular shape in cross section as shown in FIG.
The convex portion 66 of the outer mold 46 corresponding to the concave portion 42 is of a right triangle shape as a matter of course.

  Here, the concave portion 42, specifically, the convex portion 66 of the outer mold 46, moves the end portion of the extruded product 10 </ b> A in the axial direction as the diameter-enlarged mold 50 is pushed when the diameter-enlarged mold 50 is pushed. In this sense, when the concave portion 42 and the corresponding convex shape portion 66 are formed into a right triangle shape, the surface in the direction perpendicular to the axis of the convex shape portion 66 is the outer mold with respect to the inclined surface (slanted side). It is desirable to provide it in such a shape as to be positioned on the axial end side of 46.

Next, in FIG. 15B, the shape of the convex portion 66 is substantially semicircular in cross section, and a plurality of the convex portions 66 are provided so as to be continuously located in the axial direction. This is an example formed in a shape.
In the example of FIG. 15C, a plurality of such semicircular convex portions 66 are provided at a predetermined pitch apart in the axial direction, and the concave portions 42 are formed into corresponding shapes by these convex portions 66. This is an example.

Further, in the example of FIG. 15D, the convex portion 66 is formed in a trapezoidal cross section, and a plurality of the convex portions 66 are provided at a predetermined pitch slightly spaced apart in the axial direction, thereby forming the corresponding concave portions 42. This is an example that is formed.
Furthermore, in the example of FIG. 15E, the convex portions 66 are similarly formed in a trapezoidal cross section, and are provided in a plurality of rows continuously in the axial direction so that the concave portions 42 are formed in corresponding shapes. This is an example.
In the example of FIG. 15F, the convex portions 66 are formed in a quadrangular cross section, and are provided in multiple rows in the axial direction at predetermined intervals so that the concave portions 42 are formed into corresponding shapes. This is an example.
What has been described above is merely an example, and the concave portion 42 and the convex shape portion 66 can be provided in various other shapes.

Furthermore, a large number of the concave portions 42 can be formed at a small pitch in the axial direction as shown in FIG. 16 (a), and at a larger pitch as shown in (b). Many can be provided in the axial direction.
Alternatively, as shown in (c), it is also possible to provide the recess 42 partially only at the shaft end, that is, at the opening end.
In this case, it is desirable to provide the recess 42 in such a shape that the bottom surface is a flat surface.
FIG. 17 shows a state at the time of molding the hose 10 when the concave portion 42 is provided in such a form, specifically, a state at the time of molding the enlarged diameter portion 30.

  Although the embodiments of the present invention have been described in detail above, these are merely examples, and the present invention can be configured and implemented in various forms and modes without departing from the spirit of the present invention.

It is the perspective view which showed the hose of one Embodiment of this invention with the fitting metal fitting. It is an enlarged view of a connection part with the joint metal fitting of the hose of the embodiment. It is sectional drawing which shows the hose of the same embodiment with the elements on larger scale of the principal part. It is a figure of the shaping device of the hose of the embodiment. It is the figure which decomposed | disassembled and showed the shaping | molding apparatus of FIG. 4 to each component. It is a figure of the outer mold | type of the shaping | molding apparatus of FIG. FIG. 7 is a perspective view of the outer mold of FIG. 6. It is explanatory drawing of the principal part process of the manufacturing method of the hose of the embodiment. It is process explanatory drawing following FIG. It is process explanatory drawing following FIG. It is a figure of the hose of other embodiments of the present invention. It is a figure of the hose of other embodiment of this invention. It is a figure of the hose of other embodiment of this invention. It is a figure of the hose of other embodiment of this invention. It is a figure of the principal part of the hose of other embodiment of this invention. It is a figure of the principal part of the hose of other embodiment of this invention. It is explanatory drawing of the principal part process of the manufacturing method of the hose of FIG. It is a figure which shows an example of a conventionally well-known hose. It is a figure of the conventionally well-known hose different from FIG. It is explanatory drawing of the principal part process of the hose manufacture of FIG. 19, and its malfunction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Hose 10A Extrusion product 12 Joint metal fitting 16 Rubber inner layer 18 Reinforcement layer 20 Rubber outer layer 22 Insert pipe 30 Diameter expansion part 32 Main part 36,42 Concavity 44 Convex part 46 Outer type 48 Mandrel 50 Diameter expansion type 54 Molding surface 56 Forming concave 58 Main part molding surface 60 Diameter expansion part molding surface 62, 66 Convex part 72 Fitting hole

Claims (12)

A laminated structure having a reinforcing layer formed by braiding reinforcing wire rods interposed between the rubber inner layer and the rubber outer layer, and each end has an enlarged shape with respect to the main portion on the center side, both the inner diameter and the outer diameter. A joint tool having a rigid insert pipe inserted into the enlarged diameter portion and a socket fitting externally fitted to the enlarged diameter portion and caulked in the reduced diameter direction is formed in the enlarged diameter portion. An end diameter-enhancing hose to be mounted, wherein a recess having a shape recessed toward the axial center side is partially provided on an outer surface of the main part in the axial direction. A laminated structure having a reinforcing layer formed by braiding reinforcing wire rods interposed between the rubber inner layer and the rubber outer layer, and each end has an enlarged shape with respect to the main portion on the center side, both the inner diameter and the outer diameter. A joint tool having a rigid insert pipe inserted into the enlarged diameter portion and a socket fitting externally fitted to the enlarged diameter portion and caulked in the reduced diameter direction is formed in the enlarged diameter portion. An end diameter-enhancing hose to be mounted, wherein a recess having a shape recessed toward the axial center is provided on an outer surface of the diameter-enlarged part.   The end diameter-expanding hose according to claim 1, wherein the concave portion is provided in a form continuously extending in the circumferential direction along the outer surface of the main portion.   2. The end diameter-expanded hose according to claim 1, wherein the concave portions are provided at a plurality of positions in the axial direction.   2. The end diameter-expanding hose according to claim 1, wherein the concave portion is provided in a shape extending in the axial direction, partially in the circumferential direction and provided at a plurality of locations in the circumferential direction.   2. The end expansion according to claim 1, wherein the recesses are arranged at a predetermined pitch in the axial direction so that the axial cross-sectional shape of the outer surface of the main portion is a continuous serrated uneven shape. Diameter hose.   The end diameter-expanding hose according to claim 2, wherein the concave portion is provided in a form continuously extending in the circumferential direction along the outer surface of the diameter-expanded portion.   The end diameter-expanded hose according to claim 2, wherein the concave portion is partially provided in the axial direction.   The end diameter-expanding hose according to claim 2, wherein a plurality of the concave portions are arranged in the axial direction.   The end portion according to claim 9, wherein the recesses are arranged at a predetermined pitch in the axial direction so that the axial cross-sectional shape of the outer surface of the enlarged diameter portion is a continuous serrated uneven shape. Expanded hose. It is a manufacturing method of the end part diameter expansion hose of Claim 1,
(A) The end portion provided with a main portion molding surface provided with a convex portion corresponding to the concave portion and a large diameter portion molding surface for molding the outer surface of the large diameter portion, which molds the outer surface of the main portion. An outer mold having a molding surface having a shape corresponding to the outer shape of the expanded-diameter hose, and an axially penetrating molding recess formed inside the molded surface, and (b) the end-diameter expanded hose With a mandrel that molds the inner surface of the main part,
The mandrel is inserted into an unvulcanized or semi-vulcanized straight tubular extruded product having the rubber inner layer, rubber outer layer and reinforcing layer obtained by extrusion molding, and the extruded product is combined with the mandrel. In a state of being inserted and set in the molding recess of the outer mold,
Thereafter, the center portion has a fitting hole slidably fitted to the mandrel, and has a shape corresponding to the inner surface of the enlarged diameter portion, and forms the inner surface of the enlarged diameter portion. A diameter-expanding die having an outer surface is inserted into the end of the extruded product in the axial direction along the mandrel to expand the end, and the inner surface of the end is expanded by the diameter-expanding die. A method for producing an end diameter-expanded hose, wherein an outer surface is molded by the outer mold, and then the extruded product is heated together with the outer mold, the mandrel and the diameter-expanded mold and completely vulcanized. It is a manufacturing method of the end part diameter expansion hose of Claim 2,
(A) The end portion provided with a main portion molding surface that molds the outer surface of the main portion and an outer surface of the enlarged diameter portion, and a large diameter portion molding surface provided with a convex portion corresponding to the concave portion. An outer mold having a molding surface having a shape corresponding to the outer shape of the expanded-diameter hose, and an axially formed molding recess formed inside the molded surface, and (b) the end-diameter expanded hose With a mandrel that molds the inner surface of the main part,
The mandrel is inserted into an unvulcanized or semi-cured straight tubular extruded product having the rubber inner layer, the rubber outer layer and the reinforcing layer obtained by extrusion molding, and the extruded product is inserted into the mandrel. And in a state inserted and set in the molding recess of the outer mold,
Thereafter, the center portion has a fitting hole that is slidably fitted to the mandrel, has a shape corresponding to the inner surface of the enlarged diameter portion, and forms the inner surface of the enlarged diameter portion. A diameter-expanding die having an outer surface is inserted into the end of the extruded product in the axial direction along the mandrel to expand the end, and the inner surface of the end is expanded by the diameter-expanding die. A method for producing an end diameter-expanded hose, wherein an outer surface is molded by the outer mold, and then the extruded product is heated together with the outer mold, the mandrel and the diameter-expanded mold and completely vulcanized.

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