JPH05177275A - Device for expanding pipe - Google Patents

Abstract

PURPOSE:To uniformly expand a diameter in a pipe stock over the whole length by forming a cap type sealing having a collar fitted to a step part and assembling the sealing to a spigot joint type at both end parts of a pipe expanding medium. CONSTITUTION:At both end parts of the elastic body-made pipe expanding medium 4, tapered parts 5 and small diameter step parts 6 near the inside of axial direction of the pipe expanding medium 4 from the tapered parts are formed and on the other hand, the collers 9 fitted to the step parts 6 in the sealings 7 are arranged to form the sealing 7 as the cap type. Then, at both end parts of the pipe expanding medium 4, the sealings 7 are assembled to the spigot joint type. Therefore, at the time of expanding the pipe expanding medium 4, the tapered parts 8 of the pipe expanding medium 4 are backed up by the collar 9 in the sealing 7. Thus, trouble, for which the tapered part 8 of the pipe expanding medium 4 is protruded from the tip part of the sealing 7, is eliminated. By this method, the uniform pipe expanding force is applied over the whole length of the pipe stock through the pipe expanding medium 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe expanding device, and more particularly to a pipe expanding device suitable for uniformly expanding a material pipe to be expanded in its entire length.

[0002]

2. Description of the Related Art Conventionally, as a pressure bonding technique for joining hollow structures using a pipe expanding technique, a technique described in JP-A-54-35860 is known. This conventional technique is shown in FIG.
As shown in FIG. 3, the shaft body 21 having the liquid passage 22 is provided, the expansion medium 23 made of an elastic body arranged outside the shaft body 21, and the seal rings 25 attached to both ends of the expansion medium 23. .. A taper 24 is formed at both ends of the expansion medium 23 so as to gradually reduce the outer diameter toward the tip.
Each seal ring 25 has a taper 2 of the expansion medium 23.
A taper 26 that abuts against No. 4 is formed. Further, each seal ring 25 is fixed by a nut 27 screwed onto a male screw formed on the shaft body 21 in a state where both the tapers 24 and 26 are in contact with each other.

In this prior art, in the tube sheet 29,
Set the material tube to be expanded and crimped. Then, a tube expanding device including the shaft body 21, the tube expanding medium 23, and the seal rings 25 at both ends thereof is inserted into the material tube. Then, from the liquid passage 22 provided in the shaft body 21, the expansion medium 2
3, a high-pressure liquid is supplied to expand the tube expanding medium 23, and the expanding tube pressurizes the material tube from the inside thereof to apply a stress exceeding the yield stress to the material tube to plastically deform the tube and expand the tube 28. Are pressed into the tube sheet 29 to be joined. After that, the liquid pressure in the expansion medium 23 is reduced, and the expansion medium 23
Is contracted, and the tube expanding device is removed from the tube expanding tube 28.

[0004]

By the way, in the above-mentioned crimping and joining technique for hollow structures, the length of the material pipe is sufficiently long with respect to the thickness of the tube sheet 29, and the material pipe is expanded in diameter. Since only the ends of 28 need to be crimped to the tube sheet 29, the tube expanding device can be used.

However, as shown in FIGS. 8 and 9, the inner material pipe 30 is shorter than the outer hollow structure 31 and the outer hollow structure 31 is provided over the entire length of the inner material pipe 30. When it is necessary to crimp, the following problems occur.

That is, as shown in FIG. 8, the expansion medium 23 for expanding the diameter of the material pipe 30 having the inner diameter d and the outer diameter D of the seal ring 25 are provided in the material pipe 30.
It is necessary to form a small size for inserting the material tube 30 and to press the whole length of the material tube 30 by crimping, the length L between the expansion medium 23 and the seal rings 25 attached to both ends thereof is set to the length l of the material tube 30. It needs to be longer than (Ell). As a result, before the tube expansion, as shown in FIG. 8, the tube expansion medium 23 and the seal rings 25 attached to both ends of the tube expansion medium 23 are
It is arranged so as to project from both ends of 0. When liquid pressure is applied to the pipe expanding medium 23 in this state to expand the pipe expanding medium 23, the outer diameter of the pipe expanding medium 23 is expanded, the material pipe 30 is expanded, and the pipe expanding medium 23 is attached to both ends of the pipe expanding medium 23. The sharp corner portion of the seal ring 25 is pushed and expanded. However, since there is a limit to the deformation of the seal ring 25, as shown in FIG. 9, a part of the tube expanding medium 23 protrudes from the tip of the seal ring 25. Therefore, from the expansion medium 23 to the material pipe 30
Therefore, there is a problem that the pipe expanding force is not transmitted to the raw material pipe 30 and unexpanded portions remain at both ends of the raw material pipe 30, so that the raw material pipe 30 cannot be uniformly expanded over the entire length.

An object of the present invention is to provide a tube expanding device capable of uniformly expanding the entire length of a raw material tube.

Another object of the present invention is to provide a pipe expanding device capable of uniformly crimping an inner material pipe to an outer hollow structure over its entire length.

[0009]

The object is to form a step portion having a small diameter on the inner side in the axial direction of the pipe expanding medium rather than the taper on the outer peripheral surface of the end portion of the pipe expanding medium, and to form the seal ring with the step portion. Formed into a cap type with a collar that fits in
This is achieved by assembling seal rings in both ends of the tube expanding medium in an anchor type.

Further, the object is to form the seal ring with an elastic body which is less likely to be deformed than the tube expanding medium, and further, the region facing the tube expanding medium and the seal rings attached to both ends thereof. This can be achieved even better by disposing a thin-walled tube made of an elastic body between the above and the pressing means.

Further, the other purpose is to press the expanded pipe to the outer side of the material pipe supported outside the region extending over the expansion medium and the seal rings attached to both ends thereof. By installing a hollow structure,
To be achieved.

[0012]

According to the present invention, in addition to the taper at both ends of the expansion medium made of an elastic body, a step portion having a small diameter is formed closer to the inner side in the axial direction of the expansion medium than the taper, while the seal ring is provided with
A collar that fits the step is provided, and the seal ring is formed in a cap shape. Then, at both ends of the expansion medium,
The seal ring is assembled to the anchor type. Therefore, when the expansion medium is expanded, the tapered portions at both ends of the expansion medium are backed up by the collar of the seal ring. As a result, the problem that the tapered portion of the tube expanding medium protrudes from the tip of the seal ring is eliminated. As a result, a uniform tube expanding force is applied from the tube expanding medium over the entire length of the material tube, so that the material tube can be uniformly expanded over its entire length.

Further, in the present invention, the seal ring is formed of an elastic body that is less likely to be deformed than the tube expanding medium, that is, a hard elastic body. As a result, the collar portion of the seal ring prevents the tapered portion of the tube expanding medium from protruding and the seal ring also expands.Therefore, even with a long material tube, the tube expanding medium and the seal ring uniformly expand the diameter of the tube. can do.

Further, in the present invention, a region facing the tube expanding medium and the seal rings assembled at both ends thereof, that is, a region extending from the tip of one sealing ring to the tube expanding medium and the tip of the other sealing ring is added. A thin-walled tube made of an elastic body is installed between the pressure means and the pressure means. Then, the thin wall tube is first expanded by the pressurizing means, and the tube expanding medium and the end portion of the seal ring are expanded through the thin tube, so that the tube expanding medium and the end portion of the seal ring are evenly distributed. It can be expanded by applying expansion force. This allows the material tube to be
The diameter can be expanded more uniformly.

Further, in the present invention, the material pipe is arranged outside the region extending over the pipe expanding medium and the seal rings attached to both ends thereof, and the hollow structure for crimping the expanded pipe further outside thereof. Has been installed. Therefore, since the material pipe is uniformly expanded over the entire length by the expansion medium and the seal ring, and the expanded pipe is pressure-bonded to the outer hollow structure, the inner material pipe is attached to the outer hollow structure. Can be uniformly crimped over the entire length. In the present invention, when the hollow structure is used as a molding die, the material pipe can be expanded according to the molding die to obtain a hollow molding.

[0016]

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

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention,
2 to 6 are views showing a pipe expanding process by the pipe expanding device of the embodiment shown in FIG.

As shown in FIG. 1, the tube expanding apparatus in this embodiment has a shaft body 1 constituting a pressurizing means, an elastic tube expanding medium 4, and seal rings attached to both ends thereof. 7 and a thin tube 13 made of an elastic body.

The shaft body 1 is provided with a liquid passage 2 and an opening 3 opening from the liquid passage 2 in the radial direction of the shaft body 1. The liquid passage 2 is connected to a supply source (not shown) of high-pressure liquid.
The high pressure liquid is supplied into the space 15 between the shaft 1 and the thin tube 13 through the opening 3.

Tapers 5 are formed on the outer peripheral surfaces of both ends of the expansion medium 4 so that the outer diameter gradually decreases toward the tip. Further, on the outer peripheral surfaces of both ends of the tube expanding medium 4, stepped portions 6 having a small diameter are formed closer to the inner side in the axial direction of the tube expanding medium 4 than the taper 5.

Each of the seal rings 7 is formed of a hard elastic body that is less deformable than the tube expanding medium 4. A taper 8 and a collar 9 are formed on each seal ring 7. The taper 8 is formed so as to contact the taper 5 of the tube expanding medium 4. The collar 9 has a taper 8
Is integrally attached to the end of the tube expansion medium, and is formed so as to fit into the step 6 of the tube expanding medium 4. Each seal ring 7 is formed in a cap shape as a whole, and is attached to the end portion of the tube expanding medium 4 in an anchor type. Further, each seal ring 7 is fixed via a metal fitting 11 mounted on a male screw 10 formed on the tip of the shaft body 1 and a nut 12 screwed onto the male screw 10.

Each end 14 of the thin-walled tube 13 has a U
It is folded back in a letter shape and is housed in the taper 8 of the seal ring 7.

The tube expanding device of the above embodiment is used and operates as follows.

That is, as shown in FIG. 1, as shown in FIG. 2, from the state in which each part is contracted, the outside of the region extending from the expansion medium 4 to the ends of the seal rings 7 attached to both ends thereof. Then, the material tube 18 to be expanded in diameter is arranged.

Next, as shown in FIG. 3, when the high pressure liquid is supplied from the liquid passage 2 formed in the shaft body 1, the high pressure liquid passes through the opening 3 and enters the space 15 between the shaft body 1 and the thin tube 13. And the thin-walled tube 13 expands. When the thin tube 13 expands, the expansion medium expands due to the expansion force, and as shown in FIG. 3, the outer peripheral surface of the expansion medium 4 is in close contact with the inner peripheral surface of the material tube 18 to hold the material tube 18. ..

As described above, after expanding the tube expanding medium 4 and holding the material tube 18, the inside of the thin wall tube 13 is kept in a constant pressure state, and as shown in FIG. The material pipe 18 held on the outside is inserted and set in the pipe 20 which is a hollow structure on the outside.

After that, when the high-pressure liquid is again supplied into the space portion 15 between the shaft body 1 and the thin wall tube 13 through the liquid passage 2 and the opening 3, as shown in FIG.
3 further expands, the expansion force is transmitted to the tube expanding medium 4, and the tube expanding medium 4 and the ends of the seal rings 7 attached to both ends thereof expand. When the tube expanding medium 4 and the ends of the seal rings 7 attached to both ends of the tube expanding medium 4 expand, a tube expanding force is applied to the inside of the material tube 18 to expand the material tube 18. Then, the expanded pipe 19 is pressure-bonded to the inner peripheral surface of the pipe 20.

By the way, in this embodiment, the thin-walled tube 13 made of an elastic material is installed between the shaft body 1 and the region of the expansion medium 4 facing the seal rings 7 assembled at both ends thereof. The expansion medium 4 and the collar portion of the seal ring 7 can be expanded substantially parallel to each other through the thin tube 13. Further, a stepped portion 6 having a small diameter is formed at both ends of the tube expanding medium 4 in addition to the taper 5, while a seal ring 7 has a collar 9 fitted to the stepped portion 6 in addition to the taper 8.
Since the entire seal ring 7 is formed in a cap shape and the seal rings 7 are assembled in both ends of the tube expanding medium 4 in an anchor type, when the tube expanding medium 4 expands, the portion of the taper 5 is sealed. It can be backed up by the collar 9 so as not to protrude from the end of the ring 7, so that a uniform pipe expanding force can be applied over the entire length of the material pipe 18. Therefore, in this embodiment, the material pipe 18
It is possible to uniformly expand the diameter of the pipe 20 over its entire length and evenly press-bond it to the inner peripheral surface of the pipe 20.

The material pipe 18 is expanded and the expanded pipe 19
After being pressed and fixed to the inner peripheral surface of the pipe 20, the liquid in the space 15 is extracted through the liquid passage 2 and the opening 3.

As described above, when the liquid in the space 15 is drained, the thin tube 13, the tube expanding medium 4 and the end portion of the seal ring 7 contract and return to the original shape. After the above members are restored to the original shape, the tube expanding device is pulled out from the tube 19 which is crimped and fixed in the pipe 20 to obtain the product shown in FIG.

In this embodiment, a molding die is installed in place of the pipe 20, and the material tube 18 is expanded and expanded in diameter in the same process as described above, thereby forming a molding along the molding die. Obtainable.

[0032]

According to the invention described in claim 1 of the present invention described above, a step portion having a small diameter is formed on the inner side in the axial direction of the pipe expanding medium rather than the taper on the outer peripheral surface of the end of the pipe expanding medium. The seal ring is formed in a cap type having a collar that fits in the step portion, and seal rings are attached to both ends of the pipe expanding medium in an anchor type, and when the pipe expanding medium is expanded, the pipe expanding medium is expanded. Since the taper part of both ends of the tube is backed up by the seal ring collar, the problem that the taper part of the tube expansion medium sticks out from the tip of the seal ring is solved. Since it is added, there is an effect that the diameter of the material pipe can be uniformly expanded over its entire length.

According to the second aspect of the present invention, the seal ring is formed of an elastic body which is less likely to be deformed than the expanding medium, and further, the third aspect of the present invention. For example, since a thin-walled tube formed of an elastic body is installed between the expansion medium and the regions facing the seal rings assembled at both ends of the expansion medium, and the pressurizing means, the material tubes are There is an effect that the diameter can be expanded more uniformly over the entire length.

According to the fourth aspect of the present invention, the diameter expansion is further performed outside the material tube supported outside the area extending over the tube expansion medium and the seal rings attached to both ends of the tube expansion medium. Since the hollow structure for crimping the compressed pipe is installed, the material pipe is uniformly expanded over its entire length, and the expanded pipe is compressed to the outside hollow structure, so that the outside hollow The structure has an effect that the inner material tube can be uniformly crimped over the entire length.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention.

FIG. 2 is an explanatory view of a pipe expanding process according to the embodiment shown in FIG.

FIG. 3 is an explanatory view of a pipe expanding step following FIG.

FIG. 4 is an explanatory view of a pipe expanding step following FIG.

FIG. 5 is an explanatory diagram of a tube expanding step following FIG.

FIG. 6 is a vertical cross-sectional view of a product obtained in the example of the present invention.

FIG. 7 is a vertical sectional view showing a conventional technique.

FIG. 8 is an explanatory diagram of a pipe expanding process according to a conventional technique.

FIG. 9 is an explanatory diagram of the tube expanding step following FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Shaft which comprises pressurizing means, 2 ... Liquid passage, 4 ...
Expansion medium, 5 ... Taper of expansion medium, 6 ... Step of expansion medium, 7 ... Seal ring, 8 ... Taper of seal ring, 9
... Collar provided on the seal ring, 13 ... Thin-walled tube, 15 ... Space between shaft and thin-walled tube, 18 ... Material tube, 19 ... Expanded tube, 20 ... Pipe which is an outer hollow structure.

Front page continuation (72) Hideyo Saito, Inventor Hideyo Saito, 3-1-1 Sachimachi, Hitachi, Ibaraki Hitachi Ltd. Hitachi factory (72) Inventor, Eisaku Hayashi 3-1-1, Saiwaicho, Hitachi, Ibaraki No. Stock Company, Hitachi, Ltd., Hitachi Factory (72) Inventor, Kunio Enomoto, 502, Jinritsucho, Tsuchiura City, Ibaraki Prefecture, Institute of Mechanical Research, Hitachi, Ltd. (72) Inventor, Takayuki Numata 3-10-2 Bentencho, Hitachi City, Ibaraki Prefecture Issue Hitachi Kyowa Industry Co., Ltd. (72) Inventor Masayuki Tsumori 3-2-2 Sachimachi, Hitachi City, Ibaraki Prefecture Hitachi Engineering Service Co., Ltd.

Claims (4)

[Claims] 1. An outer peripheral surface of a pressurizing unit utilizing hydraulic pressure is formed in a hollow shape by an elastic body, and outer peripheral surfaces of both axial end portions are tapered so that an outer diameter thereof gradually decreases toward a tip portion. Arranged expanded pipe medium, at both axial ends of the expanded medium, a seal ring having a taper that abuts the taper is attached, and the expanded medium and the seal rings attached to both ends thereof, In a pipe expanding apparatus of a type in which a material pipe to be expanded is arranged, the pipe expanding medium and seal rings attached to both ends thereof are expanded, and the material pipe is expanded into a predetermined shape, the outer circumference of the end of the pipe expanding medium. A step portion having a small diameter is formed closer to the inner side in the axial direction of the pipe expanding medium than the taper on the surface, and the seal ring is formed in a cap type having a collar fitted to the step portion, and both ends of the pipe expanding medium are formed. Seal on the part A tube expansion device characterized in that the ring is assembled into an anchor type. 2. The tube expanding device according to claim 1, wherein the seal ring is formed of an elastic body that is less likely to be deformed than the tube expanding medium. 3. A thin-walled tube formed of an elastic body is installed between the expansion medium and a region facing a seal ring assembled at both ends of the expansion medium and the pressing means. Item 1. The tube expanding device according to item 1 or 2. 4. A hollow structure for crimping a diameter-expanded pipe is provided outside the material pipe supported outside the region extending over the pipe expansion medium and seal rings attached to both ends thereof. The tube expanding device according to claim 1, 2, or 3, characterized in that.