JPH11169975A - Jig for expanding tube material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a jig for expanding a tube material, by which the workability is improved and the development of dust caused by a heater is eliminated and the electric source for heater can be unnecessitated. SOLUTION: At the time of inserting a portion from the same diameter shaft part 42 of an attachment 40 to a flare part 46 into the end part of the tube material T, the end part of the tube material T is deformed and the diameter is enlarged with the flare part 46, but at the time of pulling out the end part of the tube material T from the attachment 40, since the end edge part of the tube material T is made to be shrunk to a desired inner diameter by a spring back, a process for heating and cooling the tube material T in order to easily insert the attachment 40 into the tube material T and prevent the sprig back after pulling out, is saved and the working time is shortened and the workability is improved. Further, the heater for heating the tube material T becomes unnecessary and in a job site, the development of the dust caused by the heater is eliminated and the electric source for heater is unnecessitated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tube material expanding jig for expanding an end portion of a tube material to be fitted to a joint body.

[0002]

2. Description of the Related Art Conventional jigs for expanding a tube material include, for example, those shown in FIGS.

That is, the jig shown in FIG. 13 is applied to a tube having a small inner diameter, and the jig shown in FIG. 14 is applied to a tube having a large inner diameter. is there. An attachment 2 is erected on each base 1, a small-diameter shaft portion 3 is formed at the tip of the attachment 2, a large-diameter shaft portion 4 is formed at the base end, and a small-diameter shaft portion 3 is formed.
Is approximately the same as the inner diameter of the tube material to be inserted, and the large-diameter shaft portion 4 is substantially the same as the diameter of the externally fitted portion of the joint body to which the tube material is fitted. The tube material is pushed in,
When the tube material is fitted onto the large-diameter shaft portion 4, the tube material is
The pipe is expanded to substantially the same diameter as the externally fitted portion of the joint body.

[0004]

However, in such a conventional jig for expanding a tube material, the tube material is externally fitted to the large-diameter shaft portion 4, and the tube material is fitted to the externally fitted portion of the joint body. When the tube is extracted from the jig when the tube is expanded to substantially the same diameter, the diameter of the end of the tube is reduced by springback as shown in FIG. It becomes difficult to fit into the part.

Further, the tube material is heated by a heater to facilitate deformation of the tube material, and the heated tube material is externally fitted to the large-diameter shaft portion 4, and the state in which the tube material is externally fitted is maintained for about 30 seconds. It is conceivable to cool down to room temperature and remove it afterwards to eliminate springback.However, the time required to heat the tube material and cool down to room temperature is not good, and the workability is not good. However, the use of such a method causes a problem that the work site is contaminated with dust and the like, and the work site is limited due to the necessity of a power source. The present invention has been made in view of such problems of the conventional technology, and can improve workability, can prevent contamination of a work site, and further have a work having a power supply. An object of the present invention is to provide a jig for expanding a tube material that is not limited to a site.

[0006]

The gist of the present invention to achieve the above object lies in the following inventions. [1] A jig (20) for expanding a tube material (T) for expanding an end portion of a tube material (T) to be externally fitted to an externally fitted portion of a joint body (10), wherein the jig ( 20) has an attachment (40), and the attachment (4)
0) is a small-diameter shaft portion (42), a large-diameter shaft portion (44), and
The attachment (40) having a flare portion (46);
The small-diameter shaft portion (42) is located at the distal end of the attachment (40), and has a diameter substantially equal to the inner diameter of the end of the tube material (T). The large-diameter shaft portion (44) of (40) is located in the middle of the attachment (40), and has a diameter substantially the same as the diameter of the externally fitted portion of the joint body (10). A flare portion (46) of the attachment (40).
Is located at the proximal end of the attachment (40), and the diameter of the large-diameter shaft (44) is increased toward the proximal end.
Characterized in that the end of the tube (T) is widened to the diameter of the large-diameter shaft (44) or more. Jig (20).

[2] A tube material (T) expansion jig (20) for expanding an end of a tube material (T) to be externally fitted to an externally fitted portion of a joint body (10), The jig (20) includes a jig main body (21), a clamp (30), an attachment (40), and a driving mechanism (50), and the jig main body (21) includes the clamp (30) and the attachment. At least one of the clamps (30) is supported so as to be able to be guided to a position close to and away from the clamp (30) and the other of the attachment (40). T)
The tube material (T) is gripped such that the end of the tube member (T) faces the tip of the attachment (40), and the attachment (40) has a small-diameter shaft portion (42) and a large-diameter shaft portion (4).
4) and a flare portion (46), and the small-diameter shaft portion (42) of the attachment (40) is located at the tip of the attachment (40), and the diameter of the tube material (T ) Is formed substantially the same as the inner diameter of the end portion, and the large-diameter shaft portion (44) of the attachment (40) is located at an intermediate portion of the attachment (40), and has a diameter of the joint body. The outer fitting portion of (10) is formed to have substantially the same diameter as that of the outer fitting portion, and the flare portion (46) of the attachment (40) is located at the base end of the attachment (40), and has a diameter of The diameter of the large-diameter shaft portion (44) is gradually increased toward the base end side, and the drive mechanism (50) is configured to connect the clamp (30) and the attachment (40). At least one of the clamps (30) Inserting a portion from the small-diameter shaft portion (42) to the flare portion (46) of the attachment (40) into the end of the tube material (T) so as to approach the other end of the attachment (40); A jig (20) for expanding a tube material (T).

[3] Attach the end of the tube material (T) to be externally fitted to the externally fitted portion of the joint body (10) to the attachment (4).
In the method of expanding the tube material (T) expanded according to 0), a small-diameter shaft portion (42) formed at the distal end portion and having substantially the same diameter as the inner diameter of the end portion of the tube material (T), A large-diameter shaft portion (44) having substantially the same diameter as the diameter of the externally fitted portion of the joint body (10), and a large-diameter shaft portion formed at the base end thereof and facing the base end side. An attachment (40) having a flare portion (46) having a diameter gradually larger than the diameter of (44) is supported by the jig body (21), and the tip of the attachment (40) is provided with the tube material (T). A tube material (T) characterized in that a portion from the small-diameter shaft portion (42) of the attachment (40) to the flare portion (46) is inserted into the end portion of the tube material (T) with its ends facing each other. ) Expansion method.

Next, the operation of the invention described in each of the above items will be described. In the jig (20) for expanding the tube material (T) according to [1], the end of the tube material (T) faces the front end of the attachment (40), and the end of the tube material (T). The part from the small diameter shaft part (42) of the attachment (40) to the flare part (46) is simply inserted into the part.

If a portion from the small-diameter shaft portion (42) of the attachment (40) to the flare portion (46) is inserted into the end of the tube material (T), the flare portion (46) allows the tube material (T) to be inserted. Although the edge is deformed to an enlarged diameter, if the end of the tube (T) is pulled out from the attachment (40), the edge of the tube (T) is reduced to a desired inner diameter by springback.

As a result, the steps of heating and cooling the tube material (T) are reduced, the construction time is shortened, and the workability is improved. Further, a heater for heating the tube material (T) is not required, and no dust is generated by the heater at the work site, and a power supply for the heater is not required.

[0012] In the jig (20) for expanding the tube material (T) according to [2], the clamp (30) such that the end of the tube material (T) faces the tip of the attachment (40). To grip the tube material (T). Next, at least one of the clamp (30) and the attachment (40) is moved by the driving mechanism (50).
And the other end of the attachment (40), the portion from the small-diameter shaft portion (42) of the attachment (40) to the flare portion (46) can be easily attached to the end of the tube material (T). Can be inserted.

If a portion from the small-diameter shaft portion (42) of the attachment (40) to the flare portion (46) is inserted into the end portion of the tube material (T), the flare portion (46) allows the tube material (T) to be inserted. Although the edge is deformed to an enlarged diameter, if the end of the tube (T) is pulled out from the attachment (40), the edge of the tube (T) is reduced to a desired inner diameter by springback.

Accordingly, the steps of heating and cooling the tube material (T) are reduced, the construction time is shortened, and the workability is improved. Further, a heater for heating the tube material (T) is not required, and no dust is generated by the heater at the work site, and a power supply for the heater is not required.

[0015] In the method of expanding the tube material (T) according to [3], similarly, the end portion of the tube material (T) is moved from the small-diameter shaft portion (42) of the attachment (40) to the flare portion (46).
When the portion of the tube material (T) is inserted, the end of the tube material (T) is deformed by the flare portion (46) into a state where the diameter of the tube material (T) is enlarged. When the end of the tube material (T) is pulled out from the attachment (40), the edge of the tube material (T) is reduced in diameter to a desired inner diameter.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. Each drawing shows an embodiment of the present invention. FIG. 1 is a front view of an attachment of a jig for expanding a tube material according to an embodiment of the present invention. FIG. 2 is a front view of the jig for expanding the tube material.
FIG. 3 is a partial front view of the jig for expanding the tube material. FIG. 4 is a partial front view of the jig for expanding the tube material.

As shown in FIGS. 1 to 4, a jig 20 for expanding a tube material for expanding an end portion of the tube material T includes:
A jig body 21, a clamp 30, an attachment 40, and a drive mechanism 50 are provided.

The jig body 21 includes a block portion 22 and
A handle portion 25 is formed integrally, and a guide hole 23 is formed in the block portion 22. A connection bar 24 extends from the lower surface of the block portion 22, and a clamp 30 is attached to an extension end of the connection bar 24.

A guide rod 51 constituting a drive mechanism 50 is fitted in the guide hole 23 of the block portion 22 so as to be able to reciprocate, and a screw hole is formed in the distal end surface of the guide rod 51. Attachment 40 is screwed on. Attachment 40 via guide rod 51
Are configured to be able to move back and forth between a close position close to the clamp 30 and a separated position separated therefrom.

The attachment 40 has a disk-shaped base 4.
1, a small-diameter shaft portion 42 from the tip to the base portion 41 side,
The large-diameter shaft portion 44 and the flare portion 46 are integrally formed. The small-diameter shaft portion 42 is formed to have a diameter substantially equal to the inner diameter of the end of the tube material T. In addition, the large diameter shaft 4
4 is formed so that its diameter is substantially the same as the diameter of the fitting part of the joint body 10. Further, the flare portion 46 is formed so that its diameter gradually becomes larger than the diameter of the large-diameter shaft portion 44 toward the base 41 side.

A tapered shaft portion 43 is formed between the small diameter shaft portion 42 and the large diameter shaft portion 44. A screw shaft 48 that is screwed into a screw hole of the guide rod 51 is formed on the surface of the base 41 opposite to the flare portion 46.

The driving mechanism 50 has a lever member 52. The lever member 52 has a vertically intermediate portion pivotally attached to the block portion 22, and an upper end portion of the lever member 52 is connected to a base end portion of the guide rod 51. The attachment 40 is connected to and can be driven to a close position and a separated position via the guide rod 51 by a pull operation of the lower end of the lever member 52.

A compression spring 53 is provided in a gap between the inner wall of the guide hole 23 and the guide rod 51, and is urged by the compression spring 53 in a direction in which the attachment 40 moves to the separated position. As shown in FIGS. 3 and 4,
When the attachment 40 moves to the close position, the end of the tube material T is attached to the small-diameter shaft portion 42 of the attachment 40.
To the flare section 46.

The attachment 40 has a large diameter shaft portion 4.
Without clearly distinguishing the flare portion 4 from the flare portion 4, a portion corresponding to the large-diameter shaft portion 44 and the flare portion 46 is gradually and continuously enlarged as in an attachment 140 of a modified example shown in FIG. You may form so that it may become one taper shaft part 146.

FIG. 5 is a sectional view of a main part of a clamp of a jig for expanding a tube material according to an embodiment of the present invention. FIG. 6 is a front view of the clamp of the jig for expanding the tube material.

As shown in FIGS.
Is to hold the tube material T and restrict it so that the end of the tube material T faces the tip of the attachment 40. The clamp 30 has a lower clamp part 32, an upper clamp part 34, a dial part 36, and a spring part 38.

On the lower surface of the lower clamp 32, there is formed a fitting recess 32a which is fitted to the extended end of the connecting bar 24. Further, a semi-circular cross-sectional groove 32b having a diameter substantially corresponding to the outer diameter of the tube material T to be gripped is formed on the upper surface of the lower clamp portion 32. A rubber material is adhered to the groove surface of the semicircular cross-sectional groove 32b.

Similarly, a semi-circular cross-sectional groove 34b having a diameter substantially corresponding to the outer diameter of the tube material T to be gripped is formed on the lower surface of the upper clamp portion 34. Semicircular cross-sectional groove 3
A rubber material is adhered to the groove surface of 4b.

An upper clamp portion 34 is pivotally connected to the lower clamp portion 32 so as to be openable and closable. By swinging the upper clamp portion 34 to the closed position, the semi-circular cross-sectional groove 32b of the lower clamp portion 32 and the semi-circular cross-sectional groove 34b of the upper clamp portion 34
The tube material T is configured to be sandwiched from above and below.

The dial portion 36 has a dial shaft portion 37 serving as a center axis of rotation. The dial shaft portion 37 has a screw hole (not shown) formed in the axial direction, and the screw hole is formed around the entrance periphery of the screw hole. A flange 37a is formed. Dial shaft 3
The screw hole 7 is screwed into a screw shaft portion 39 a formed in the upper end of the rod member 39.

A lower end of a rod member 39 is pivotally connected to the lower clamp 32 by a pin member 33. A concave groove 34a is formed in the upper clamp part 34. The rod member 39 is recessed into the concave groove 34a, the flange 37a of the dial portion 36 faces the groove peripheral edge of the concave groove 34a, and by rotating the dial portion 36, the flange portion 37a of the dial portion 36 becomes concave. By pressing the peripheral edge of the groove 34a,
The upper clamp portion 34 is restricted to the closed position. The spring part 38 is a dial shaft part 37 of the dial part 36.
To prevent rattling of the dial portion 36.

FIG. 7 is a sectional view showing a fitting relationship between a tube member and a joint according to an embodiment of the present invention. As shown in FIG. 7, the joint of the tube material T includes a joint body 10 made of a fluororesin and a nut member 1 made of a fluororesin.
5 The joint is made of fluororesin.

Examples of the fluororesin include "PTFE (polytetrafluoroethylene)" and "PFA (tetrafluoroethylene / perfluoroalkylvinyl ether copolymer)" which have excellent chemical resistance. Further, a fluorine resin of PFA is used for the tube material T.

The nut member 15 is a so-called cap nut, and has a back wall 17 which is a cap section orthogonal to the screw axis on the back side of the screw hole 16. Screw hole 16 of nut member 15
A female thread portion 18 is engraved on the inlet side of the nut member 15.
An insertion hole 19 for inserting a tube material into the screw hole 16 from the back wall 16 side is formed in the back wall 17 of the first embodiment.

The joint body 10 has an outer fitting portion 12 formed at a distal end portion 11 which is inserted into the screw member 16 at the back of the nut member 15. One end of the tube material T inserted into the screw hole 16 through the insertion hole 19 of the nut member 15 is fitted to the outer fitting portion 12 in a state where the diameter of the tube material T is increased. Therefore,
One end of the tube material T inserted into the screw hole 16 is
It comprises a general outer diameter portion T1, a large-diameter enlarged portion T2 which is fitted to the externally fitted portion 12, and a step portion T3 which is an intermediate portion connecting the general outer diameter portion T1 and the enlarged diameter portion T2.

An external thread portion 13 to be screwed into a female thread portion 18 is engraved on the distal end portion 11 of the joint body 10 following the externally fitted portion 12. The joint body 10 has a through hole 14 having a hole diameter substantially equal to the inner diameter of the tube material T and penetrating in the screw axis direction.
a is drilled.

FIG. 9 is a view showing one example of a dimensional relationship between a tube member and a joint according to an embodiment of the present invention.
FIG. 9A is a front view of the joint body 10, and FIG.
FIG. 9C is a front view of the attachment 40, and FIG.
It is a front view of the modification of the attachment 40.

As shown in FIG. 9, the outer diameter (φB) of the large-diameter shaft portion 44 of the attachment 40 is set slightly larger than the outer diameter (φA) of the outer fitting portion 12 of the joint body 10. I have. Similarly, the outer diameter (φC × φD) of the distal end of the tapered shaft portion 146 of the attachment 140 of the modified example is set to be larger than the outer diameter (φA) of the external fitting portion 12 of the joint body 10.

Next, the operation of the present invention will be described.
The upper clamp portion 34 of the clamp 30 is opened, the end of the tube material T is fitted into the semicircular cross-sectional groove 32b of the lower clamp portion 32, the upper clamp portion 34 is closed, and the upper clamp portion 34 is closed.
The end of the tube material T is sandwiched from above and below by the semicircular cross-sectional groove 34b of the lower clamp portion 32 and the semicircular cross-sectional groove 34b of the lower clamp portion 32. At this time, the rod member 39 is not recessed in the concave groove 34a of the upper clamp portion 34, and the clamp 30 is in the non-clamp state.

Next, the rod member 39 is pivoted about the pin member 33 so that the rod member 39 is recessed into the concave groove 34a, and the dial portion 36 is rotated, thereby causing the flange portion 37a of the dial shaft portion 37 to rotate. Makes a clamp state in which the peripheral edge of the concave groove 34a is subjected to concave pressure, and the lower clamp portion 32 and the upper clamp portion 34 grip the end of the tube material T. Thereby, the tube material T
Is the tip of the attachment 40 (small diameter shaft 42)
The tube material T is constrained in a state facing.

Next, holding the handle portion 25, the drive mechanism 5
When the user places his hand on the lever member 52 and pulls the lever member 52 against the urging force of the compression spring 53, the upper end of the lever member 52 projects the guide rod 51, and the attachment 40
Are close to the clamp 30. Thereby, as shown in FIG. 3, the end of the tube material T is attached to the attachment 40.
Is inserted into the small-diameter shaft portion 42.

Further, when the lever member 52 is pulled against the urging force of the compression spring 53, the end of the tube material T extends from the large-diameter shaft portion 44 of the attachment 40 to the flare portion 46, as shown in FIG. Insert into the part. At this time, if the pushing force of the attachment 40 into the tube material T is greater than the frictional force of the clamp 30 with respect to the tube material T, the end of the tube material T moves. What is necessary is just to clamp the end of T again.

When the hand is released from the lever member 52 after the attachment 40 is completely inserted, the guide rod 51 is immersed by the urging force of the compression spring 53, and the portion extending from the small-diameter shaft portion 42 to the flare portion 46 of the attachment 40. From the end of the tube material T. When the attachment 40 is firmly fitted to the end of the tube material T and cannot be pulled out only by the urging force of the compression spring 53, the attachment 40 may be pulled out from the end of the tube material T by hand.

Attachment 40 is attached to the end of tube material T.
If the portion from the small diameter shaft portion 42 to the flare portion 46 is inserted, the end of the tube material T is expanded by the large diameter shaft portion 44,
Further, the edge of the tube material T is deformed into a skirt shape by the flare portion 46, but if the end portion of the tube material T is pulled out from the attachment 40, the edge of the tube material T is spring-backed, and the large-diameter shaft portion 44 The diameter is reduced to approximately the same diameter as the expanded diameter. Thereby, the tube material T
There is no need to heat or cool to room temperature, so that steps such as heating are reduced, and the construction time is shortened.

FIGS. 10 and 11 show another embodiment of the present invention. The clamp 130 has a fastener 131 and an engagement groove member 132,
Has a lever 133 and a hook 134. The upper end of the lever 133 is swingably pivotally attached to the lower clamp 32, and the engagement groove member 132 is fixed to the upper clamp 34. The hook 134 is formed in an inverted U-shape. When the hook 134 is engaged with the engagement groove member 132 and pivoted so as to push down the lever 133, the tube material is formed by the semicircular cross-sectional groove 32b of the lower clamp portion 32 and the semicircular cross-sectional groove 34b of the upper clamp portion 34. It is configured to sandwich T from above and below.

FIG. 12 shows another embodiment of the present invention. The drive mechanism 150 is configured such that when the handle 151 is rotated in the normal and reverse directions, the slide shaft 153 is protruded and retracted by the slide screw 152, and the attachment 40 moves forward and backward. Further, the drive mechanism may be a mechanism using a toggle link that changes the rotational movement to the slide movement of the attachment 40.

[0047]

According to the jig for expanding tube material according to the present invention, if a portion from the small-diameter shaft portion of the attachment to the flare portion is inserted into the end portion of the tube material, the end of the tube material is formed by the flare portion. The edge is deformed to an expanded state, but if the end of the tube material is pulled out of the attachment, the end of the tube material is reduced in diameter to the desired inner diameter by springback, so insert the attachment into the tube material. The steps of heating and cooling the tube material, which are easy and prevent springback after being pulled out, are reduced, the construction time is shortened, and the workability is improved. In addition, a heater for heating the tube material is not required, and no dust is generated by the heater at the work site, and a power supply for the heater can be eliminated.

[Brief description of the drawings]

FIG. 1 is a front view of an attachment of a jig for expanding a tube material according to an embodiment of the present invention.

FIG. 2 is a front view of a jig for expanding a tube material according to an embodiment of the present invention.

FIG. 3 is a partial front view of a jig for expanding a tube material according to an embodiment of the present invention.

FIG. 4 is a partial front view of a jig for expanding a tube material according to an embodiment of the present invention.

FIG. 5 is a sectional view of a main part of a clamp of a jig for expanding tube material according to an embodiment of the present invention.

FIG. 6 is a front view of a clamp of a jig for expanding a tube material according to an embodiment of the present invention.

FIG. 7 is a cross-sectional view showing a fitting relationship between a tube member and a joint according to one embodiment of the present invention.

FIG. 8 is a front view showing a modification of the attachment of the jig for expanding the tube material according to the embodiment of the present invention.

FIG. 9 is a diagram showing a dimensional relationship between a tube material and a joint according to one embodiment of the present invention.

FIG. 10 is a front view of a clamp of a jig for expanding a tube material according to another embodiment of the present invention.

FIG. 11 is a side view of a clamp of a jig for expanding a tube material according to another embodiment of the present invention.

FIG. 12 is a front view of a jig for expanding a tube material according to another embodiment of the present invention.

FIG. 13 is a front view of a clamp of a jig for expanding tube material according to a conventional example.

FIG. 14 is a front view of a clamp of a jig for expanding a tube material according to a conventional example.

FIG. 15 is an operation explanatory view of a tube material according to a conventional example.

[Explanation of symbols]

 T ... Tube material T1 ... General outer diameter portion T2 ... Expanded diameter portion T3 ... Stepped portion 10 ... Joint body 12 ... External fitting portion 20 ... Jig for expanding tube material 21 ... Jig body 22 ... Block portion 23 ... Guide Hole 24 ... Connection bar 25 ... Handle 30 ... Clamp 32 ... Lower clamp 32a ... Fit recess 32b ... Semicircular cross section groove 33 ... Pin member 34 ... Upper clamp section 34a ... Concave groove 34b ... Semicircular cross section groove 36 ... Dial Part 37 ... Dial shaft part 37a ... Flange part 38 ... Spring part 39 ... Rod member 39a ... Screw shaft part 40 ... Attachment 41 ... Base part 42 ... Small diameter shaft part 44 ... Thick diameter shaft part 46 ... Flare part 50 ... Drive mechanism 51 ... guide rod 52 ... lever member 53 ... compression spring 140 ... attachment 146 ... taper shaft part

Claims (3)

[Claims] 1. A jig for expanding a tube material for expanding an end portion of a tube material to be externally fitted to an externally fitted portion of a joint main body, wherein the jig has an attachment, and the attachment has a thin shape. A radial shaft portion, a large-diameter shaft portion, and a flare portion, wherein the small-diameter shaft portion of the attachment is located at a tip of the attachment, and has a diameter substantially equal to an inner diameter of an end of the tube material. The large-diameter shaft portion of the attachment is located at an intermediate portion of the attachment, and has a diameter substantially equal to the diameter of the externally fitted portion of the joint body. The flare portion is located at the base end of the attachment, and is formed so that its diameter gradually increases toward the base end side from the diameter of the large-diameter shaft portion. Edge of the large diameter shaft part Jig tubing pipe expansion, characterized in that spreading over. 2. A jig for expanding a tube material for expanding an end portion of a tube material to be externally fitted to an externally fitted portion of a joint main body, wherein the jig includes a jig main body, a clamp, an attachment, and A driving mechanism, the jig body supports at least one of the clamp and the attachment so as to be able to be guided to a position close to and away from the clamp and the other of the attachment, and the clamp includes: The tube material is gripped so that the end of the tube material faces the tip of the attachment, and the attachment has a small-diameter shaft portion, a large-diameter shaft portion, and a flare portion, and the small diameter of the attachment. The shaft portion is located at the distal end of the attachment, and has a diameter substantially equal to the inner diameter of the end of the tube material. The part is located in the middle part of the attachment, and the diameter thereof is formed to be substantially the same as the diameter of the externally fitted part of the joint body. The flare part of the attachment is formed at the base end of the attachment. And the diameter thereof is formed so as to gradually increase from the diameter of the large-diameter shaft portion toward the base end side.The drive mechanism controls at least one of the clamp and the attachment, A jig for expanding a tube material, wherein a portion from a small-diameter shaft portion to a flare portion of the attachment is inserted into an end of the tube material so as to approach the other of the clamp and the attachment. 3. A tube expanding method for expanding an end portion of a tube material to be externally fitted to an externally fitted portion of a joint body by an attachment. A small diameter shaft portion having substantially the same diameter, a large diameter shaft portion formed at an intermediate portion thereof and having a diameter substantially equal to the diameter of the externally fitted portion of the joint body,
The jig body supports an attachment formed at the base end thereof and having a flare portion having a diameter gradually larger than the diameter of the large-diameter shaft portion toward the base end side, wherein the tube is provided at the tip end of the attachment. A tube expanding method for a tube material, wherein ends of the material are opposed to each other, and a portion from a small-diameter shaft portion of the attachment to a flare portion is inserted into the end of the tube material.