JP2004190702A - Hose with bellows type metal tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrict the generation of fatigue breakdown of a bellows type metal tube in an axial directional end thereof due to the internal pressure to be repeatedly applied, in regard to a hose with a bellows type metal tube having the bellows type metal tube as an inner layer thereof. <P>SOLUTION: This hose 10 with a bellows type metal tube is formed by fitting a socket fitting 6 on an axial directional end of a hose body 12, which has the bellows type metal tube 22 as an inner layer thereof and which is formed by laminating an outside layer including a reinforcing layer 20 outside in the radial direction, and caulking the socket fitting inward in the radial direction. Diameter of a bellows part 24 side end of a straight shape part 26 as a constraining part for constraining an axial directional end of the bellows part 24 of the bellows type metal tube 22 is formed at an intermediate value between the diameter of an angle part 24a and the diameter of a valley part 24b of the adjacent bellows parts 24. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a hose with a bellows metal pipe suitable as a hose for transporting fuel for automobiles and a hose for transporting refrigerants and other fluids, and more particularly to a hose having a characteristic axial end structure.
[0002]
BACKGROUND OF THE INVENTION
Conventionally, as a fuel transport hose for automobiles, a general rubber hose having good vibration absorption and assembling properties, such as NBR / PVC (a blend of acrylonitrile butadiene rubber and polyvinyl chloride) having excellent gasoline permeability resistance, etc. However, in recent years, regulations on permeation of fuels for automobiles and the like are strict from the viewpoint of global environmental protection, and it is expected that the regulations will be further strengthened in the future. On the other side, hydrogen gas and carbon dioxide used in fuel cells It is necessary to cope with a fluid having a high permeability such as a gas refrigerant, and it is expected that a hose made of only an organic material such as rubber or resin will have difficulty satisfying required performance.
[0003]
Therefore, as a form of a low permeability hose in the future, the use of a hose having a bellows metal tube in the inner layer, which can be expected to have a very high fluid impermeability, is being studied.
[0004]
Conventionally, as this type with a bellows metal tube, those disclosed in Patent Literature 1, Patent Literature 2, and Patent Literature 3 are known.
In the case of this hose with a bellows metal tube, even when hydrogen gas used in a fuel cell is used, gas permeation can be made zero by the inner bellows metal tube, that is, gas permeation can be completely prevented.
[0005]
FIG. 5 shows, as a comparative example, a hose devised by the present inventors as a hose with a bellows metal tube of this type.
In the figure, reference numeral 200 denotes a hose body, which has a bellows metal tube 202 in the innermost layer, and has a cross-sectional structure in which an outer layer including an inner elastic layer 204, a reinforcing layer 206, and an outer elastic layer 208 is laminated radially outside. I have.
[0006]
210 is a socket fitting externally fitted to the end of the hose body 200 in the axial direction, which is caulked radially inward.
By caulking the socket fitting 210, the end of the hose body 200 in the axial direction is sandwiched between the rigid insert pipe 212 and the socket fitting 210 from inside and outside in the radial direction. And the socket fitting 210.
[0007]
The bellows metal tube 202 is integrally formed with a straight-shaped portion (straight tube portion) 214 extending straight in the axial direction on the axial end portion side. , Is fixed to the insert pipe 212.
[0008]
The straight portion 214 has an extending portion 216 that is exposed from an outer layer including the inner elastic layer 204, the reinforcing layer 206, and the outer elastic layer 208 and extends in the axial direction. By being sandwiched in the radial direction by the inward flange portion 218 of the socket fitting 210 and the engagement groove 220 formed in the insert pipe 212 at a position corresponding to the flange portion 218, the straight shape portion 214, that is, the bellows metal tube 202 is formed. The outer surface of the insert pipe 212 is hermetically sealed and the straight portion 214 is prevented from coming off in the axial direction.
The straight portion 214 has the same outer diameter as the maximum outer diameter of the bellows portion (complete bellows portion) 222 in the bellows metal tube 202, that is, the diameter of the peak portion of the bellows portion 222.
[0009]
By the way, in the case of the hose with the bellows metal tube, when the internal pressure acts, the bellows metal tube 202 expands and deforms in the axial direction as shown in FIG.
At this time, as shown by a two-dot chain line in FIG. 7A, the bellows pitch expands in the axial direction and the bellows portion 222 extends, whereby the peak portion 222a is reduced in diameter and the valley portion 222b is expanded in diameter. Deform.
That is, the ridges 222a and the valleys 222b are reduced in diameter and expanded so as to face the center diameter of the bellows 222 (the median between the diameters of the ridges 222a and the valleys 222b).
[0010]
On the other hand, the straight portion 214 does not deform in the radial direction when an internal pressure is applied, and as a result, as schematically shown in FIG. 2B, the diameter between the straight portion 214 and the adjacent bellows portion 222 is increased. Steps are generated in the direction, and large distortion and stress are locally generated in the bellows portion 222, particularly in a portion close to the straight portion 214. Therefore, when a pressure repetition test in which the internal pressure is repeatedly applied is performed, there is a problem that the bellows portion 222 may be fatigue-ruptured at a location where the above-mentioned large local distortion or stress occurs (particularly, the peak portion 222a or the valley portion 222b). found.
[0011]
The above is an example of the case where the straight-shaped portion 214 is provided on the axial end portion side of the bellows metal tube 202. However, the case where the axial-direction end of the bellows portion 222 is directly welded to the insert pipe 212 or the straight-shaped portion 214 is provided. In place of the incomplete bellows, that is, an incomplete bellows in which the pitch of the bellows is larger than the original bellows (complete bellows) 222 from the beginning and the difference between the diameter of the peak and the diameter of the valley is small. In such a case, as a result, they act as restraining portions at the axial ends of the bellows portion, which may cause the same problem as described above.
[0012]
Although the above description has been made with reference to the example of the hose for transporting hydrogen gas used in the fuel cell, a similar problem is encountered in hoses for transporting fuel such as gasoline, for preventing gasoline from scattering into the atmosphere or high output of equipment. When a hose with a bellows metal tube is used due to the increase in temperature and pressure (that is, the necessity of low permeation becomes remarkable) due to gasification, CO ₂ having a small molecular weight and high gas permeability as hydrogen is used as a refrigerant (fluid) like hydrogen. This is a problem that can occur commonly when a hose with a bellows metal tube is used as the fluid transport hose to be used, or when a hose with a bellows metal tube is used in other fields where gas transmission regulations are strict.
[0013]
[Patent Document 1]
JP 2001-182872 A [Patent Document 2]
JP 2001-341230 A [Patent Document 3]
Japanese Utility Model Publication No. 51-150511
[Means for Solving the Problems]
The hose with a bellows metal tube of the present invention has been devised to solve such a problem.
According to a first aspect of the present invention, a socket metal fitting is externally fitted to an axial end of a hose body having a bellows metal tube as an inner layer and an outer layer including a reinforcing layer laminated on a radially outer side. A hose with a bellows metal tube crimped inward, wherein the diameter of the full bellows side end of the restraining portion for restraining the axial end of the full bellows portion of the bellows metal tube is changed to the diameter of the adjacent full bellows portion. It is characterized in that it has an intermediate diameter between the diameter of the peak and the diameter of the valley.
[0015]
According to a second aspect of the present invention, in the first aspect, the diameter of the restraint portion at the side of the complete bellows portion is 部 of the diameter obtained by subtracting the diameter of the valley portion from the diameter of the peak portion of the adjacent complete bellows portion. Is within a range of ± 5% of the diameter of.
[0016]
According to a third aspect of the present invention, in any one of the first and second aspects, the restraining portion is an axially straight portion integrally formed on an axial end side of the bellows metal tube. .
[0017]
[Action and effect of the invention]
As described above, according to the present invention, when the bellows metal tube is elongated and deformed by the action of the internal pressure, the radial step between the restraining portion that restrains the end of the bellows portion (complete bellows portion) and the adjacent bellows portion is reduced. Focusing on the problem that a large distortion and stress occur in the bellows part due to the occurrence, a radial step between the restraining part and the adjacent bellows part is not generated even when the internal pressure is applied, or the step is reduced. It is something to do.
Specifically, the bellows side end of the restraining portion is configured to have an intermediate diameter between the diameter of the peak and the diameter of the valley of the adjacent bellows.
[0018]
With this configuration, when the bellows portion adjacent to the restraining portion expands and deforms in the axial direction due to the action of the internal pressure, the restraining portion has a strong resistance to the diameter reduction and the diameter expansion deformation of the peaks and valleys. Therefore, it is possible to solve the problem that the strong resistance force generates a large strain and stress locally in the bellows part, particularly in a part close to the constrained part, and the bellows metal tube is fatigue-ruptured there. Can be.
[0019]
In the present invention, the diameter of the bellows side end of the restraint portion is set to ± 5% of the diameter of the center of the adjacent bellows, specifically, １ ／ of the diameter obtained by subtracting the diameter of the valley from the diameter of the crest. (Claim 2).
[0020]
The present invention is preferably applied to a case where the straight-shaped portion 214 integrally formed on the axial end side of the bellows metal tube 202 forms a restraining portion as shown in FIG. (Claim 3).
However, when the axial end of the bellows part is welded to the insert pipe, the insert pipe forms a restraining part, or the incomplete bellows part integrally formed on the axial end side of the bellows metal pipe is The present invention is applicable even in the case of forming a restraining portion.
[0021]
【Example】
Next, embodiments of the present invention will be described in detail with reference to the drawings.
1 and 2, reference numeral 10 denotes a hose with a bellows metal tube (hereinafter simply referred to as a hose) suitable as a hydrogen transport hose, a vehicle fuel transport hose, a refrigerant transport hose for an air conditioner, and the like. And 14, a metal insert pipe fixed to the hose body 12, and 16 a socket fitting externally fitted to the axial end of the hose body 12.
[0022]
The socket fitting 16 is caulked radially inward, so that the end of the hose body 12 in the axial direction is sandwiched by the insert pipe 14 and the socket fitting 16 from both inside and outside in the radial direction. 14 and the socket bracket 16.
[0023]
The hose body 12 has a bellows metal tube 22 as an innermost layer, and an inner elastic layer 18, a reinforcing layer 20, and an outer elastic layer 21 are laminated on the radial outside thereof, and these are integrally formed by vulcanization bonding or the like. It is fixed.
In this example, the inner elastic layer 18, the reinforcing layer 20, and the outer elastic layer 21 constitute an outer layer for the bellows metal tube 22.
[0024]
In this example, the reinforcing layer 20 is formed by braiding reinforcing wires at opposite angles to each other at a predetermined braiding angle.
This reinforcing layer 20 may be a fiber reinforcing layer or a wire reinforcing layer.
The inner elastic layer 18 and the outer elastic layer 21 can be made of a material having elasticity such as rubber.
[0025]
On the other hand, the innermost layer of the bellows metal tube 22 has a bellows portion (complete bellows portion) 24 substantially in the axial direction, and the bellows portion 24 provides flexibility.
That is, although the innermost layer is formed of a metal tube, the hose 10 of this example is provided with flexibility by providing the bellows portion 24 on the metal tube as a whole.
[0026]
As the material of the bellows metal tube 22, steel (including stainless steel), copper or copper alloy, aluminum or aluminum alloy, nickel or nickel alloy, titanium or titanium alloy, or the like can be used, but stainless steel is more preferable. It is.
[0027]
The thickness of the plate can be set to 20 to 500 μm, but is preferably 50 μm or more in consideration of prevention of defects such as pinholes and workability of the bellows portion 30, and 300 μm or less from the viewpoint of flexibility and durability. It is desirable to do.
[0028]
The bellows metal tube 16 is integrally formed with a straight portion (straight tube portion) (constraint portion) 26 extending straight in the axial direction at the axial end portion side. It is externally fitted and fixed to the insert pipe 14.
[0029]
The straight portion 26 has an extending portion 28 which is exposed from an outer layer composed of the inner elastic layer 18, the reinforcing layer 20, and the outer elastic layer 21 and extends in the axial direction. The straight fitting 26, that is, the bellows metal tube 16 is sandwiched in the radial direction by the inward flange 30 of the socket fitting 16 and the engagement groove 32 formed in the insert pipe 14 at the axial position corresponding thereto. The seal and the outer surface of the insert pipe 26 are sealed, and the straight portion 26 is prevented from coming off the insert pipe 14 in the axial direction.
[0030]
In this example, the outer diameter Dc (including the outer diameter of the bellows portion 24 side end) _Dc (see FIG. 3) of the straight portion 26 serving as a restraining portion at the axial end of the bellows portion 24 has a peak in the bellows portion 24. diameter between the diameter _{D b} of the diameter _{D a} and valley portions 24b of the parts 24a being the (intermediate size).
In this particular example, the center diameter of the outer diameter _{D c} is the bellows portion 24, i.e., a range of ± 5% of just 1/2 of the diameter of the diameter minus the diameter _{D b} of the _{D a} valley 24b of the ridges 24a Inside diameter.
[0031]
The diameter _{D a} of this example ridges 24a is 8.5 mm, the diameter _{D b} of the valley 24b is Fai5.5Mm, the plate thickness t is the 0.15 mm.
The bellows pitch P is set to P = 1.2 mm.
[0032]
In the case of the hose with a bellows metal pipe 10 of the present embodiment as described above, the bellows portion 24 is accompanied by the axial expansion of the bellows pitch, the diameter reduction of the peak portion 24a, and the diameter expansion deformation of the valley portion 24b due to the action of the internal pressure. When extended in the axial direction, as shown in the schematic diagram of FIG. 4, the straight-shaped portion 26, particularly the right end of the bellows portion 24 on the right side in the figure, is reduced in diameter of the crest portion 24a and deformed in the valley portion 24b. It has no particular effect on the resistance to the expansion deformation.
Therefore, the bellows portion 24 including the peak portions 24a and the valley portions 24b can be freely reduced in diameter and expanded in diameter without being particularly subjected to tensile resistance by the straight portion 26. That is, the bellows portion 24 can freely extend in the axial direction.
[0033]
The outer diameter of the straight portion 26, more precisely, the outer diameter at the end of the bellows portion 24 is the center diameter of the bellows portion 24 or an outer diameter close thereto, and when the bellows portion 24 is expanded and deformed, FIG. This is because the step in the radial direction as shown in (1) is not particularly generated, or even if the step is generated, it is slight.
[0034]
Therefore, according to the present embodiment, even when the bellows portion 24 repeatedly expands and contracts in the axial direction due to the repetitive action of the internal pressure, the bellows portion close to the straight shape portion 26, particularly the bellows portion close to the straight shape portion 26, The generation of locally large strain and stress at the peaks 24a and the valleys 24b of the 24 is suppressed, and the problem that fatigue fracture occurs therefrom can be solved.
[0035]
The embodiment of the present invention has been described in detail above, but this is merely an example.
For example, the present invention welds the axial end of the bellows portion 24 to the insert pipe 14 and, even when the insert pipe 14 serves as a restraining portion of the bellows portion 24, determines the outer diameter in accordance with the present invention. Problem can be solved.
[0036]
Alternatively, when the incomplete bellows portion is formed integrally with the end portion in the axial direction of the bellows metal tube 22 instead of the straight-shaped portion 26, even when the incomplete bellows portion acts as a restraining portion, the problem is not caused. The above-mentioned problem can be solved by determining the outer diameter of the bellows part 24 side end in the complete bellows part according to the present invention.
In addition, the present invention can be configured in variously modified forms without departing from the spirit thereof.
[Brief description of the drawings]
FIG. 1 is a view showing a hose with a bellows metal tube according to an embodiment of the present invention.
FIG. 2 is a vertical sectional view of a main part of the embodiment.
FIG. 3 is an enlarged view showing a main part of a bellows portion adjacent to the insert pipe in the embodiment.
FIG. 4 is an explanatory diagram for explaining the operation of the embodiment.
FIG. 5 is a comparative example diagram showing a hose with a bellows metal tube devised by the present inventors as a comparative example.
FIG. 6 is an explanatory view showing a state of expansion and contraction of a bellows metal tube.
FIG. 7 is an explanatory diagram of a defect that has occurred in the comparative product of FIG. 5;
[Explanation of symbols]
Reference Signs List 10 Hose with bellows metal tube 12 Hose body 16 Socket fitting 18 Inner elastic layer 20 Reinforcement layer 21 Outer elastic layer 22 Bellows metal tube 24 Bellows part (complete bellows part)
24a Mountain part 24b Valley part 26 Straight shape part

Claims (3)

With a bellows metal tube which has a bellows metal tube in the inner layer, and a socket fitting is externally fitted to the axial end of a hose body obtained by laminating an outer layer including a reinforcing layer on the outside in the radial direction and radially inwardly crimped. A hose,
The diameter of the complete bellows side end of the restraining portion that restrains the axial end of the complete bellows portion in the bellows metal tube is the intermediate diameter between the diameter of the peak and the valley of the adjacent complete bellows. A hose with a bellows metal tube, characterized by what has been done. 2. The method according to claim 1, wherein a diameter of a side of the complete bellows portion of the restraining portion is ± 5% of a diameter which is a half of a diameter obtained by subtracting a diameter of a valley from a diameter of a peak portion of the adjacent complete bellows portion. A hose with a bellows metal tube characterized by being within the range. The hose with a bellows metal tube according to any one of claims 1 and 2, wherein the restraining portion is an axial straight portion integrally formed on an axial end side of the bellows metal tube.

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