JP2000310117A - Flexible tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flexible tube capable of improving strength in the vicinity of a tip part of a bellows part. SOLUTION: In the vicinity of an end part 2a of a bellows part 2, that is, a range extending over substantially entire length in an axial direction of an outer cylinder member 5, for instance, a synthetic resin 7 is imparted over an entire periphery in a trough part 2d on an outer periphery side. The synthetic resin 7 is injected in a liquid state into the trough part 2d when the bellows part 2 and an outer blade 4 are welded on a tubular member 3 and is solidified. As a result, a crest part 2b and a trough part 2c in the vicinity of the end part 2a are constrained, deformation of the parts 2b and 2c is suppressed and stress concentration to the vicinity of the end part 2a and a welding part 6 is mitigated. Coil-shaped members 8, 9 for inner periphery and outer periphery may be wound on trough parts 2e, 2d on an inner periphery side and the outer periphery side. For the trough parts 2d, 2e on the outer periphery side and the inner periphery side, outside divided and fixed parts and inside divided and fixed parts having each fitting shaped higher parts may be fitted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible tube having a bellows-like bellows.

[0002]

2. Description of the Related Art Conventionally, there has been known a flexible tube in which a bellows portion which can expand and contract in the axial direction and a tubular member such as an exhaust pipe are fixed to each other at their respective ends.
In this flexible tube, generally, the bellows portion has a ridge portion and a valley portion that are continuous in the axial direction, and the ridges and valleys are deformed to be able to expand and contract.

FIG. 5 is a partial longitudinal sectional view of a conventional flexible tube.

[0004] The flexible tube 101 is formed by fixing an end of a bellows portion 102 and an end of a tubular member 103 such as an exhaust pipe.

The bellows portion 102 has ridges and valleys that are continuous in the axial direction, the outer periphery is formed in a wavy shape (so-called bellows shape), and these ridges and valleys are deformed when subjected to an external force. Thereby, the bellows portion 102 can be extended and contracted in the axial direction. The outer circumference of the bellows portion 102 is surrounded and protected by the outer blade 104 over substantially the entire length. In the bellows portion 102, an outer tube member 105 is externally fitted around the end portion (near the portion fixed to the tubular member 103) of the bellows portion 102 and is protected.

Bellows 102, outer blade 10
4 and each end of the outer tubular member 105 are fixed to the end of the tubular member 103 by welding over the entire circumference (welded portion 106),
Thereby, an integrated flexible tube 101 is configured.

[0007]

However, in the above-mentioned conventional flexible tube, each component is basically fixed only by the weld bead (weld portion 106), so that there is a problem in strength. Was.

That is, depending on the usage of the flexible tube, as the force applied to the vicinity of the end of the bellows portion 102, expansion / contraction, bending (A in the drawing) and torsion (B in the drawing) due to pressurization / decompression of the fluid can be considered.

First, when the bellows portion 102 expands and contracts in the axial direction due to pressurization / decompression of a fluid or the like, most of the force acts on the welded portion 106 and its vicinity through deformation of the peaks and valleys of the bellows portion 102. Therefore, damages such as cracks and cracks are likely to occur in the vicinity of the welded portion 106 of the welded portion 106 and the bellows portion 102. Further, when a bending force acts, one of the bellows portions 102 expands and the other contracts, so that the same phenomenon as described above may occur even when the bending force acts.
Furthermore, even when a torsional force acts, most of the force acts on the welded portion 106 and its vicinity, and the same phenomenon as described above may occur.

As described above, in the conventional flexible tube, most of the force applied in various use modes acts intensively in the vicinity of the welded portion 106 or the welded portion 106 of the bellows portion 102, and the sufficient strength is obtained only by the welded portion 106. Since it is difficult to secure the strength, there has been a problem that the ends of the welded portion 106 and the bellows portion 102 are easily damaged.

The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a flexible tube capable of improving the strength near the end of a bellows portion.

[0012]

According to a first aspect of the present invention, there is provided a flexible tube having ridges and valleys continuous in an axial direction, wherein the ridges and valleys are deformed. An end portion of the bellows portion that can be expanded and contracted in the axial direction and an end portion of the tubular member are fixedly attached to each other. In a flexible tube, the outer peripheral side near the end portion of the bellows portion fixed to the tubular member. It is characterized in that at least one of the valley and the valley on the inner peripheral side is fitted with a suppressing member for suppressing deformation of the ridge and the valley that are continuous in the axial direction.

[0013] With this configuration, deformation of the ridges and valleys that are continuous in the axial direction near the end of the bellows portion fixed to the tubular member is suppressed, so that expansion and contraction of the bellows portion is suppressed. Therefore, it is possible to suppress stress concentration on the end of the bellows portion and the portion fixed to the tubular member. Therefore, the strength near the end of the bellows portion can be improved.

According to a second aspect of the present invention, there is provided a flexible tube according to the first aspect of the present invention, wherein the fitting of the restraining member is performed by injecting resin, winding a ring-shaped member, and spiraling. It is characterized by being done by at least one of the winding of the shape member.

With this configuration, when the resin is injected into the outer peripheral valley or the inner peripheral valley near the end fixed to the tubular member of the bellows, these valleys are filled with the resin without any gap. Therefore, deformation of the peaks and valleys that are continuous in the axial direction is efficiently suppressed, and expansion and contraction near the end of the bellows is suppressed. Therefore, it is possible to improve not only the strength against the expansion and contraction and the bending force but also the strength against the torsional force to some extent. In addition, if the injected resin is made to adhere to the surface of the valley, the reinforcing effect can be enhanced especially against the torsional force. on the other hand,
According to the winding of the ring-shaped member and the winding of the helical member, the expansion and contraction of the bellows portion is suppressed, and in particular, the strength against expansion and contraction and bending force can be improved. The effect of reinforcing the bellows portion can be further enhanced by performing the resin injection and the winding of the ring-shaped member and / or the winding of the spiral member together.

In order to achieve the same object, the flexible tube according to the third aspect of the present invention has a ridge and a valley that are continuous in the axial direction, and the ridge and the valley are deformed to expand and contract in the axial direction. In a flexible tube in which the end of a possible bellows portion and the end of a tubular member are fixed,
An outer member having a shape to be fitted to a valley portion on the outer peripheral side of the bellows portion and being fitted and fixed to an outer peripheral surface near the end portion fixed to the tubular member of the bellows portion; The bellows portion has at least one of an inner member fitted to and fixed to an inner peripheral surface near the end of the bellows portion.

With this configuration, the outer member has a shape that fits into the valley portion on the outer peripheral side of the bellows portion, and is fitted to the outer peripheral surface near the end portion fixed to the tubular member of the bellows portion. By fixing, there is no gap in the valley portion on the outer peripheral side, deformation of the ridge portion and the valley portion that are continuous in the axial direction is efficiently suppressed, and expansion and contraction of the bellows portion are suppressed. on the other hand,
Since the inner member has a shape that fits into the inner peripheral valley of the bellows portion, the inner member is fitted and fixed to the inner peripheral surface near the end of the bellows portion, thereby forming the inner peripheral valley. There is no gap in the part, the deformation of the ridges and valleys that are continuous in the axial direction is efficiently suppressed, and the expansion and contraction of the bellows part is suppressed.
Therefore, it is possible to suppress stress concentration on the end of the bellows portion and the portion fixed to the tubular member. Therefore, the strength near the end of the bellows portion can be improved. In addition, by fitting and fixing both the outer member and the inner member, the reinforcing effect of the bellows portion can be further enhanced.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 is a partial longitudinal sectional view showing the structure of a flexible tube according to a first embodiment of the present invention. In the figure, the upper half is shown in cross section.

The flexible tube 1 has a bellows 2
And a tubular member 3 such as an exhaust pipe.

The bellows portion 2 has ridges 2b and valleys 2c that are alternately continuous in the axial direction, and its outer periphery is formed in a wavy shape (so-called bellows shape). When the valley 2c is deformed, the bellows 2
Are extendable in the axial direction.

The outer periphery of the bellows portion 2 is surrounded by the outer blade 4 over substantially the entire length. The outer blade 4 is formed by knitting a large number of wires (not shown) arranged obliquely with respect to the axial direction of the bellows portion 2 to form a cylindrical shape. Bellows part 2 by outer blade 4
The whole is protected from internal forces (for example, pressure or a change thereof due to a fluid flowing inside the bellows portion 2).

In the vicinity of the end 4a of the outer blade 4,
An outer cylindrical member 5 is fitted around the outer periphery, and the outer cylindrical member 5 causes the vicinity of the end 2a of the bellows portion 2 to be subjected to an internal force (for example, a pressure due to a fluid flowing inside the bellows portion 2 or a change thereof). Protected.

The ends 2a, 4a and 5a of the bellows portion 2, the outer blade 4 and the outer cylindrical member 5 are fixed to the end 3a of the tubular member 3 by welding over the entire circumference (welded portion 6). The flexible tube 1 is formed integrally by the welded portion 6.

In this embodiment, the bellows portion 2
Is applied to the outer periphery of the resin.

That is, near the end 2a of the bellows portion 2,
For example, a synthetic resin 7 is provided over the entire circumference of a valley 2d (a portion corresponding to a valley when viewed from the outside) of the outer peripheral side of the bellows portion 2 in a range extending over substantially the entire length of the outer cylinder member 5 in the axial direction. I have. The synthetic resin 7 is a resin having low elasticity when solidified, and almost fills the entire spiral space formed by the outer blade 4 and the outer blade 4d.

As a result, the ridges 2b and the valleys 2c near the end 2a of the bellows portion 2 are restrained and their deformation is suppressed, so that the expansion and contraction of the bellows portion 2 is suppressed.
In addition, since the synthetic resin 7 and the surface of the valley portion 2d on the outer peripheral side are in close contact with each other, the displacement of the bellows portion 2 in the vicinity of the end 2a is suppressed even with a force in the torsion direction. As a result, stress concentration on the end portion 2a of the bellows portion 2 and the welded portion 6 is reduced.

It is more preferable that the synthetic resin 7 be in a state of being adhered to the surface of the valley portion 2d on the outer peripheral side of the bellows portion 2 after solidification. By doing so, the end 2a of the bellows portion 2 is completely fixed, and sufficient reinforcement can be achieved especially in the torsion direction.

When the present flexible tube 1 is manufactured, for example, when the bellows portion 2 and the outer blade 4 are welded to the tubular member 3, the synthetic resin 7 in a liquid state is injected into the outer peripheral side valley portion 2d and solidified. It should be done. The other end (not shown) of the flexible tube 1 has the same configuration.

According to the present embodiment, the synthetic resin 7 is provided on the outer peripheral side valley 2d near the end 2a of the bellows portion 2, so that the peak 2b and the valley near the end 2a of the bellows 2 are provided. The portion 2c is restrained, and their deformation is suppressed. Therefore, even if the flexible tube 1 receives a bending force or an expansion / contraction force due to pressurization / decompression of the internal fluid, expansion and contraction of the bellows portion 2 is small, and stress concentrates on the end 2 a of the bellows portion 2 and the welded portion 6. That can be alleviated. Further, since the synthetic resin 7 and the surface of the valley portion 2d on the outer peripheral side are in close contact with each other, the displacement in the vicinity of the end 2a of the bellows portion 2 is suppressed even with a force in the torsion direction, and the end of the bellows portion 2 Part 2a
In addition, concentration of stress on the welded portion 6 can be reduced. Therefore, the strength near the end 2a of the bellows portion 2 can be improved, and the end 2a of the bellows portion 2 and the welded portion 6 can be prevented from being damaged such as cracks and cracks, and the durability can be improved. Can be.

It is most desirable to apply the synthetic resin 7 over the entire circumference. However, even when the synthetic resin 7 is applied in a part of the area,
It is possible to improve the strength of the welded portion 6 to some extent.

Although the synthetic resin 7 is applied to the outer peripheral side of the bellows part 2, it may be applied to the inner peripheral side, or more effectively if applied to both the outer peripheral side and the inner peripheral side. It is.

(Second Embodiment) FIG. 2 is a partial longitudinal sectional view showing the structure of a flexible tube according to a second embodiment of the present invention. In the figure, the upper half is shown in cross section.

The structure of the flexible tube 10 in this embodiment is different from that of the first embodiment in that
Is replaced by an inner peripheral coil-shaped member 8 and an outer peripheral coil-shaped member 9 (spiral member), and other configurations are the same. Therefore, the configurations of the bellows portion 2, the tubular member 3, the outer blade 4, the outer tubular member 5, and the welded portion 6 of the flexible tube 10 are the same as those of the flexible tube 1 according to the first embodiment.

In the second embodiment, the inner peripheral coil-shaped member 8 and the outer peripheral coil-shaped member 9 are provided on the inner and outer peripheries of the bellows portion 2. Each of the coil members 8, 9 is made of, for example, metal, but may be made of hard rubber. The thickness of each of the coil-shaped members 8 and 9 is set to an extent that the coil-shaped members 8 and 9 can be sufficiently accommodated in the inner peripheral valley 2e and the outer peripheral valley 2d, respectively.

The inner peripheral coil-shaped member 8 is wound around the inner peripheral valley 2 e of the bellows portion 2, and the outer peripheral coil-shaped member 9 is wound around the outer peripheral valley 2 d of the bellows portion 2. I have. The range in which the coil members 8 and 9 are wound is, for example, the bellows portion 2 as in the case of the synthetic resin 7 in the first embodiment.
, For example, over the substantially entire length of the outer cylinder member 5 in the axial direction.

The two coil members 8 and 9 are wound before the welding process by the welding portion 6. The other end (not shown) of the flexible tube 10 has the same configuration.

According to this embodiment, the coil members 8, 9 are wound around the inner valley 2e and the outer valley 2d in the vicinity of the end 2a of the bellows portion 2. The peak 2b and the valley 2c in the vicinity of the end 2a of the second 2 are restrained, and their deformation is suppressed. Therefore, the same effect as in the first embodiment can be obtained with respect to the bending force applied to the flexible tube 1 and the strength against the expansion and contraction force due to the pressurization / decompression of the internal fluid.

The diameter of the inner peripheral coil-shaped member 8 as a coil is set to be larger in the free state than when it is wound around the inner peripheral valley 2 e of the bellows 2. It is desirable to do. Thus, after the inner peripheral coil-shaped member 8 is wound around the inner peripheral valley 2e, the bellows 2
Is constantly urged in the outer peripheral direction, so that the contact state with the inner peripheral valley portion 2e can be always secured, and the deformation of the ridge portion 2b and the valley portion 2c of the bellows portion 2 can be more efficiently suppressed. Can be. For the same reason, it is desirable that the diameter of the outer peripheral coil-shaped member 9 is set to be smaller in the free state than in the winding state. In this case, since the bellows portion 2 is constantly urged in the inner circumferential direction, the contact state with the outer peripheral side valley portion 2d can be always ensured. In these cases, by appropriately securing the contact state, the end portion 2a of the bellows portion 2 and the welding portion 6 can be protected against the torsional force applied to the flexible tube 10.
Can enhance the reinforcing effect. In such a configuration, a desired biasing force may be obtained at the time of use by using a shape memory alloy or the like in consideration of the temperature of the applied fluid and the like.

The coil members 8, 9 according to the present embodiment
Is more effective if it is provided in addition to the synthetic resin 7 of the first embodiment.

The cross-sectional shape of each of the coil members 8, 9 is not limited to a circular shape, but may be any shape that can maintain contact with the valleys 2e, 2d.

The shape of each of the coil members 8 and 9 is not limited to a helical unitary member, but may be formed in a ring shape, for example, and a plurality of these may be fitted in the bellows portion 2 (ring shape). Element). In that case, the ring-shaped member may be partially torn. In the case of a ring shape, a certain degree of effect can be obtained even if the outer cylindrical member 5 is wound around the entire range over the substantially entire length in the axial direction, or even if it is partially wound (for example, every other valley). Can be Further, only one of the coil members 8 and 9 may be provided, and even in such a case, a certain effect can be obtained.

(Third Embodiment) FIG. 3 is a partial longitudinal sectional view showing the structure of a flexible tube according to a third embodiment of the present invention. In the figure, the upper half is shown in cross section.

In this embodiment, the end 2 of the bellows 2
In order to suppress expansion and contraction in the vicinity of a, an inner divided fixing part 21 (inner member) and an outer divided fixing part 23 (outer member) are provided on the inner and outer peripheries of the bellows portion 2. The configurations of the bellows portion 2 and the tubular member 3 are the same as in the first embodiment.

FIG. 4 is an external perspective view of the outer divided fixing part 23 (FIG. 9A) and the inner divided fixing part 21 (FIG. 9B). Each of the divided fixed parts 21 and 23 is a part of a form obtained by dividing a cylindrical part into three parts.
FIG. 1 illustrates one of them. Each of the divided fixing parts 21 and 23 is formed of, for example, a synthetic resin. After being attached to the flexible tube 20, each of the divided fixing parts 21 and 23 has a substantially cylindrical shape in a set of three.

The outer divided fixing part 23 has a crest 23a of a fitting shape with respect to the trough 2d on the outer peripheral side of the bellows part 2 (FIG. 7A). Three outer split fixing components 23 are arranged on the outer peripheral surface near the end 2a of the bellows portion 2 (only one cross section is shown), and as shown in FIG.
"a" is fitted to the inner peripheral side valley portion 2e. The outer periphery of the bellows part 2 is excluded except for the range in which the outer split fixed part 23 is fitted.
As in the first embodiment, the outer blade 4 surrounds almost the entire length. Outer blade 4
The portion corresponding to the outer divided fixed component 23 has a larger diameter than the other portions, and the outer periphery of the outer divided fixed component 23 is surrounded by the enlarged diameter portion of the outer blade 4. Shedding is prevented. In the vicinity of the end 4a of the outer blade 4, an outer tubular member 5 is externally fitted around the outer periphery.

The inner divided fixing part 21 has a crest 21a which is fitted into the trough 2e on the inner peripheral side of the bellows part 2 (FIG. 4B). Three inner split fixing parts 21 are arranged on the inner peripheral surface near the end 2a of the bellows part 2 (only one cross section is shown), and as shown in FIG.
a is fitted into the outer peripheral side valley 2d. A cylindrical pipe member 22 is inserted into the inner periphery of the inner divided fixed part 21, thereby preventing the inner divided fixed part 21 from falling off.

Each end 2 a, 4 a, 5 a of the bellows portion 2, the outer blade 4 and the outer cylinder member 5 is connected to a pipe member 22.
Is welded to the end 3a of the tubular member 3 along the entire circumference together with the protruding edge 22a provided at the left end of the flexible tube 20 (welded portion 6).
Are configured as one.

When assembling the flexible tube 20, first, the outer divided fixing part 23 and the inner divided fixing part 21 are fitted into the bellows portion 2, the pipe member 22 is inserted and fixed on the inner periphery, and the outer blade 4 is fixed from the outer periphery side. ,
The outer cylinder member 5 is fitted. Thereafter, the components can be assembled by welding. The other end (not shown) of the flexible tube 20 has the same configuration.

According to this embodiment, the outer divided fixed part 23 and the inner divided fixed part 21 are fitted and fixed to the bellows part 2 near the end part 2a of the bellows part 2, so that the end part 2a of the bellows part 2 is fixed. Peaks 2b and valleys 2c in the vicinity
Are restrained, and their deformation is suppressed. Therefore, the same effects as those of the first embodiment can be achieved with respect to the strength against the bending force and the torsional force applied to the flexible tube 1 and the expansion and contraction force due to the pressurization / decompression of the internal fluid.

The outer divided fixed part 23 and the inner divided fixed part 21 are configured as three parts.
The mode of division does not matter as long as it does not interfere with the assembling work. In addition, since it is only necessary to suppress the deformation of the peaks 2b and the valleys 2c of the bellows portion 2, there may be some clearance between the divided parts in the fitted state.

[0052]

As described above, according to the first aspect of the present invention,
According to the flexible tube, the concentration of stress on the end of the bellows portion and the portion fixed to the tubular member can be suppressed, and the strength near the end of the bellows portion can be improved.

According to the flexible tube according to the second aspect of the present invention, the injection of the resin not only can improve the strength against expansion and contraction and bending force, but also can provide some strength against torsion force. Can be improved. According to the winding of the ring-shaped member and the winding of the helical member, the expansion and contraction of the bellows portion is suppressed, and in particular, the strength against expansion and contraction and bending force can be improved.

According to the flexible tube according to the third aspect of the present invention, it is possible to suppress stress concentration on the end of the bellows portion and the portion fixed to the tubular member, and to improve the strength near the end of the bellows portion. it can.

[Brief description of the drawings]

FIG. 1 is a partial longitudinal sectional view showing a configuration of a flexible tube according to a first embodiment of the present invention.

FIG. 2 is a partial longitudinal sectional view showing a configuration of a flexible tube according to a second embodiment of the present invention.

FIG. 3 is a partial longitudinal sectional view showing a configuration of a flexible tube according to a third embodiment of the present invention.

FIG. 4 is an external perspective view of an outer divided fixed part (FIG. 4A) and an inner divided fixed part (FIG. 4B).

FIG. 5 is a partial longitudinal sectional view of a conventional flexible tube.

[Explanation of symbols]

1 Flexible tube, 2 Bellows part, 2a
End, 2b crest, 2c trough, 2d outer trough, 2e inner trough, 3 tubular member, 4
Outer blades, 5 outer cylinder members, 6 welds,
Reference Signs List 7 synthetic resin (suppression member), 8 inner peripheral coil member (spiral member), 9 outer peripheral coil member (spiral member), 21 inner divided fixed part (inner member), 2
3 Outside divided fixed parts (outside member)

Continued on front page F-term (reference) 3G004 BA05 DA14 DA15 EA03 FA08 GA01 GA06 3H111 AA03 BA01 BA15 CA44 CA47 CB27 CB28 CC17 DA26 DB11 DB20

Claims (3)

[Claims] An end of a bellows portion having an axially continuous crest and a valley, which can be expanded and contracted in the axial direction by deformation of the crest and the valley, and an end of a tubular member. A flexible tube formed by fixing the bellows portion to at least one of an outer peripheral valley portion and an inner peripheral valley portion in the vicinity of the end portion fixed to the tubular member of the bellows portion; And a suppressing member for suppressing deformation of the valley portion. 2. The fitting of the restraining member includes at least one of injection of resin, winding of a ring-shaped member, and winding of a spiral-shaped member.
The flexible tube according to claim 1, wherein the flexible tube is formed by one. 3. An end portion of a bellows portion having an axially continuous crest and a valley portion and having the crest portion and a valley portion deformable and capable of expanding and contracting in the axial direction, and an end portion of the tubular member. A flexible tube that is fixed to the outer peripheral surface of the bellows portion near the end portion fixed to the tubular member of the bellows portion and fixed to the outer peripheral surface of the bellows portion. An outer member, and at least one of an inner member having a shape to be fitted to a valley portion on the inner peripheral side of the bellows portion and being fitted and fixed to an inner peripheral surface near the end portion of the bellows portion. Characteristic flexible tube.