JP2008155214A - Tube end-machining tool, and tube end-machining method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tube end-machining tool with which thickening of a drawn part is eliminated and the drawing work of the tube end and working of a deformed cross section are performed without increasing the labor, time and cost for the working. <P>SOLUTION: In the tube end working tool 1 for drawing the tube end part of a tube stock 20, a cylindrical die 2 having a drawing part 2a which is a smaller diameter d<SB>2</SB>than the outside diameter D<SB>2</SB>of the tube stock 20 on the inner surface and a punch 2 having an ironing part 3a the outside diameter d<SB>1</SB>of which is smaller than the inside diameter D<SB>1</SB>of the tube stock 20 are arranged on the outer surface so that the drawing part 2a of the cylindrical die 2 and the ironing part 3a of the punch 3 are in the approximately same position in the axial direction, and also the cylindrical die 2 and the punch 3 are fixed concentrically through a compression spring 4. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a pipe end processing tool for drawing or deforming a pipe end portion of a raw pipe and a pipe end processing method using the same, and more specifically, to increase the thickness of the pipe end processing portion of the raw pipe. The present invention relates to a tube end machining tool capable of performing the above-mentioned tube end machining without increasing the thickness or increasing the number of steps, and a tube end machining method using the same.

  A refrigerant pipe made of aluminum or the like is used for a pipe for transporting a refrigerant such as a vehicle air conditioner (air conditioner). In such a pipe, a flange is attached to a pipe end of the pipe, and the pipe end is inserted into a connection port of an apparatus to be connected, and at the same time, a bolt is inserted into a bolt hole provided in the flange and is fixed to the apparatus. In general, an O-ring groove is formed in the pipe end portion to seal a refrigerant or the like.

  A conventional pipe end processing method for forming such an O-ring groove will be described below in the order of steps with reference to FIG. FIG. 5 is a schematic process diagram for explaining a pipe end processing method according to a conventional example. FIG. 5 (a) is a schematic diagram showing a pipe end expanding process, and FIG. 5 (b) is a pipe expanded. FIG. 5C is a schematic diagram showing a final process for forming an O-ring groove. FIG.

(1) First, a caulking part 32 and a pipe expansion part 30a are formed by press-fitting a die set in a press machine (not shown) into the pipe 30 to which the flange 31 is attached (FIG. 5A).
(2) Next, a drawn die attached to a press machine is pressed on the expanded pipe end portion and drawn to form a drawn portion 30b (FIG. 5B).
(3) Further, although the process drawing is omitted, the corner of the drawing portion 30b is formed at a substantially right angle by pressing using another mold.
(4) Finally, the tube end portion is expanded again to perform punching to form the O-ring groove 30c (FIG. 5C).

  Further, details of the drawing processing according to the conventional example shown in FIG. 5B will be described with reference to FIG. 6A and 6B are schematic process diagrams for explaining a drawing method according to a conventional example. FIG. 6A is a schematic cross-sectional view showing a state before the drawing process is started, and FIG. 6B is a drawing process. FIG. 6C is a schematic cross-sectional view showing the state after drawing processing.

  According to the drawing method according to this conventional example, after setting the expanded pipe 30a and the drawing die 33 in a press machine (not shown) (FIG. 6A), the drawing die 33 is advanced. Drawing is performed on the pipe end portion of the raw tube 30a to form a drawing portion 30b (FIG. 6B). Finally, the drawing die 33 is retracted and pulled out from the pipe end, and the processing is finished (6 (c)).

However, in the drawing of such tube ends, as shown in FIG. 6 (c), drawn portion 30b a thickness t ₂ of the reduced diameter is drawn, of course thick than mother tube wall thickness t ₁ Become meat. Since the outer diameter of the drawn portion 30b needs to be a dimension defined as an O-ring groove, it cannot be made a predetermined dimension or more.

  For this reason, the thickness that is thickened by drawing must be absorbed on the inner diameter side. When the inner diameter is reduced in this way, the pressure loss of the refrigerant or the like transporting in the pipe is increased, resulting in a decrease in the flow rate. For example, in the case of an air conditioner pipe, it is desirable to avoid a reduction in the inner diameter of the pipe as much as possible because it leads to a reduction in the refrigerating capacity due to the pressure loss.

  Therefore, as a processing method that can eliminate the increase in the thickness of the reduced diameter portion due to such drawing processing, the modified cross-section processing method according to the conventional example can be applied. (See Non-Patent Document 1). 7A and 7B are schematic process diagrams for explaining a modified cross-section processing method according to a conventional example. FIG. 7A is a schematic cross-sectional view showing a pipe end drawing process, and FIG. 7B is a punch. FIG. 7C is a schematic cross-sectional view showing the final step of retracting the drawing die.

(1) First, the deformed punch 41 whose outer peripheral surface 41a has a deformed shape is inserted in advance from the tube end of the raw tube 30a (circled number 1 in FIG. 7A).
(2) Next, a deformed die 40 whose inner peripheral surface 40a has a deformed shape is press-fitted from the tube end, and the outer diameter of the raw tube 30a is subjected to deformed drawing (circled number 2 in FIG. 7 (a)). .
(3) With the deformed mold 40 stopped, the inner deformed punch 41 is retracted, and ironing is performed between the deformed mold 40 and the outer deformed mold 40 to obtain accuracy (circled number 3 in FIG. 7B). .
(4) After pulling out the odd-shaped punch 41, the deformed die 40 is retracted to finish the processing (circled number 4 in FIG. 7C).
Edited by Japan Society for Technology of Plasticity, “Tube Forming-Secondary Processing of Pipe Materials and Product Design”, p140, Corona (1998)

  Therefore, by applying the modified cross-section processing method according to the conventional example to the above-described drawing processing, it is possible to eliminate the thickening of the drawing portion. However, by applying the modified section processing method of the pipe end according to the above-described conventional example, the thickening of the drawn portion can be eliminated, but the processing steps are from 2 steps shown in FIG. 6 to 4 shown in FIG. There is a problem that the number of steps increases, and the labor and cost of processing increase accordingly.

  Accordingly, an object of the present invention is to eliminate the increase in the thickness of the drawn portion, and to perform a pipe end machining tool capable of drawing the pipe end portion and processing a modified cross section without increasing the labor and cost of machining. It is in providing the pipe end processing method using this.

  That is, in order to achieve the above object, the means employed by the pipe end processing tool according to claim 1 of the present invention is a pipe end processing tool for drawing a pipe end portion of a raw pipe. A cylindrical mold having a drawing part smaller in diameter than the outer diameter on the inner surface, and a punch having an ironing part smaller in outer diameter than the inner diameter of the base tube on the outer surface, the drawing part of the cylindrical mold and the The punching ironing part is disposed so as to be substantially at the same position in the axial direction, and the cylindrical mold and the punch are concentrically fixed via a compression spring.

  The means adopted by the pipe end working tool according to claim 2 of the present invention is a pipe end working tool for deforming a pipe end of a raw pipe, wherein a deformed drawing part different from the cross-sectional shape of the raw pipe is provided. A cylindrical mold having an inner surface, and a punch having an outer surface having a squeezing processing portion whose outermost dimension is smaller than the inner diameter of the base tube, and a deformed drawing processing portion of the cylindrical mold and a squeezing processing portion of the punch. The cylindrical mold and the punch are concentrically fixed via a compression spring while being arranged so as to be substantially at the same position in the axial direction.

  The means adopted by the pipe end processing method according to claim 3 of the present invention uses the pipe end processing tool according to claim 1 or 2 and press-fits the cylindrical mold into the pipe end of the base pipe. The outer surface is drawn or deformed while compressing the compression spring, and then the punch having the ironing portion having the outermost dimension smaller than the inner diameter of the raw tube is removed on the outer surface, and the compression spring is extended to expand the compression spring. It is characterized by ironing the inner surface of the processed part.

  According to the pipe end processing tool according to claim 1 of the present invention, in the pipe end processing tool for drawing the pipe end portion of the raw pipe, the drawing end portion having a diameter smaller than the outer diameter of the raw pipe is provided on the inner surface. A cylindrical mold and a punch having an outer surface having an ironing portion whose outer diameter is smaller than the inner diameter of the blank tube, and the drawing portion of the cylindrical die and the ironing portion of the punch are substantially the same in the axial direction. The cylindrical mold and the punch are concentrically fixed via a compression spring while being arranged so as to be positioned.

  As a result, it is possible to integrate the drive for moving the cylindrical mold and the punch forward or backward, and forward-pressing the processing tool against the tube end of the raw tube to reduce the outer diameter. Then, in two steps of retreating and ironing the inner diameter, a drawn portion having the same wall thickness as that of the base tube is obtained.

  Moreover, according to the pipe end processing tool according to claim 2 of the present invention, in the pipe end processing tool for deforming the pipe end portion of the base pipe, the deformed drawing processing portion different from the cross-sectional shape of the base pipe is provided. A cylindrical mold having an inner surface, and a punch having an outer surface having a squeezing processing portion whose outermost dimension is smaller than the inner diameter of the base tube, and a deformed drawing processing portion of the cylindrical mold and a squeezing processing portion of the punch. The cylindrical mold and the punch are concentrically fixed via a compression spring while being arranged so as to be substantially at the same position in the axial direction.

  As a result, it is possible to integrate the drive for moving the cylindrical mold and the punch forward or backward, and the outer diameter is deformed by advancing and press-fitting the processing tool into the tube end of the raw tube. Then, in two steps of retreating and ironing the inner diameter, the processed portion is not thickened, and a tube end portion having a cross-sectional shape different from that of the raw tube is obtained.

  On the other hand, according to the pipe end processing method according to claim 3 of the present invention, the tube end processing tool according to claim 1 or 2 is used to press-fit the cylindrical mold into the pipe end of the base pipe. The outer surface is drawn or deformed while compressing the compression spring, and then the punch having the ironing portion having the outermost dimension smaller than the inner diameter of the raw tube is removed on the outer surface, and the compression spring is extended to expand the compression spring. Because the inner surface of the machined part is ironed, it is possible to perform pipe-end drawing and irregular drawing without increasing the wall thickness of the machined part and without the labor and cost of machining. .

  Furthermore, when the outer diameter is drawn or deformed by the cylindrical mold, the compression spring connected to the cylindrical mold and the punch is press-fitted in a compressed state. However, at the time of ironing of the inner diameter by the punch, the compression spring connected to the cylindrical mold and the punch is extracted in an extended state, so that the processing is performed. There is an effect that ironing can be performed while backing the back of the part with the inner wall of the cylindrical mold.

  Hereinafter, a pipe end processing tool and a pipe end processing method using the same according to Embodiment 1 of the present invention for drawing a pipe end portion of a raw pipe will be described with reference to FIGS. 1 and 2. . FIG. 1 is a schematic process diagram for explaining a pipe end machining tool and a pipe end machining method using the same according to Embodiment 1 of the present invention in the order of steps, and FIG. FIG. 1B is a schematic cross-sectional view showing a state in which the pipe end working tool is advanced and the pipe end is drawn, and FIG. 1C is a backward drawing of the pipe end working tool. FIG. 1D is a schematic cross-sectional view showing a state after finishing the drawing, and FIG. 1D is a schematic cross-sectional view showing a state after the completion of processing. FIG. 2 is a cross-sectional view taken along the line XX of FIG.

First, the configuration of the tube end machining tool according to Embodiment 1 of the present invention will be described. Reference numeral 1 denotes a tube end processing tool for drawing a tube end portion of the raw tube 20, which includes a cylindrical mold 2 and a punch 3, and connects the cylindrical mold 2 and the punch 3. It is configured to be concentrically fixed to a pedestal 5 via a compression spring 4 that performs the above operation. Then, the cavity 2c of the cylindrical mold 2, after the introducing portion 2b formed on the inclined surfaces, the inner peripheral surface than the outer diameter D ₂ smaller diameter d ₂ to become drawn portion 2a of the base pipe 20 Is formed.

On the other hand, the punch 3, ironing portion 3a having an outer diameter d ₁ than the inner diameter D ₁ smaller diameter of the mother tube 20 is formed on the outer peripheral surface. And the drawing process part 2a of the said cylindrical metal mold | die 2 and the ironing process part 3a of the said punch 3 are arrange | positioned so that it may become a substantially the same position in an axial direction, and the said cylindrical metal mold | die 2 and the punch 3 are It is fixed concentrically to the pedestal 5 via the compression spring 4. The cross section of the cylindrical mold 2 has an annular shape as shown in FIG. 2, and the cross section of the bunch 3 has a circular shape.

Here, “substantially the same position in the axial direction” means that the length of the drawing portion 2a of the cylindrical mold 2 and the length of the ironing portion 3a of the punch 3 are not necessarily the same length. This means that the portion is at least partially overlapped in the axial direction. The punch 3, when retracting the tube end machining tool 1, the inner surface of the processed throttle portion 20a in base pipe 20 by ironing by ironing portion 3a having an outer diameter d _1, the thickness of the mother tube 20 it is a tool for the same wall thickness and t _1.

Thus, the narrowed portion 20a thickness t ₂ after ironing is made to be the same as the thickness t ₁ of the base pipe 20, the inner diameter d ₂ of the cylindrical mold 2 of drawn portion 2b an outer diameter _{d 1} of the ironing portion 3a of the punch _3, it is important to form a dimensional relationship such that _{(d 2 -d 1) / 2} = t 1.

  As will be described later, the compression spring 4 is compressed when the tube end machining tool 1 is moved forward to press-fit the cylindrical mold 2 into the base tube 20 for drawing, and the cylindrical mold 2 is compressed. The ironing portion 3a formed on the punch 3 is avoided from the drawing portion 2a formed on the inner surface, and conversely, the inner surface of the drawing portion 20a is retracted while the tube end machining tool 1 is retracted and the punch 3 is extracted from the drawing portion 20a. When the ironing process is performed, the throttle part 20a at the end of the pipe is backed up from the back side of the ironing part 3a formed on the punch 3, and the outer diameter of the throttle part 20a is expanded by the ironing process. It plays a role to prevent.

Next, a pipe end drawing method using such a pipe end working tool 1 according to the first embodiment of the present invention will be described in the order of steps.
(1) First, the pipe end machining tool 1 is attached to the tool side of a press machine (not shown), and the raw pipe 20 is attached to the fixed base side to complete preparation for pipe end drawing (FIG. 1A).
(2) Next, when the tube end working tool 1 is advanced, the inclined portion 2b of the inner surface of the cylindrical mold 2 contacts the tube end of the raw tube 20, and the tube end of the raw tube 20 is the inclined portion At the same time, the compression spring 4 is compressed along the line 2b.

(3) When the tube end machining tool 1 is further advanced, the tube end of the raw tube 20 is drawn along the drawing portion 2a of the cylindrical mold 2 (FIG. 1 (b)). When drawing of a predetermined length is completed, the pipe end working tool 1 is moved backward. Then, the drawn portion 20a at the end of the tube is brought into close contact with the drawn portion 2a of the retreating cylindrical mold 2, and the cylindrical mold 2 is pulled, so that the compression spring 4 is gradually extended.

(4) Then, the drawing portion 2a of the cylindrical mold 2 and the ironing portion 3a of the punch 3 are restored to their original positions that are substantially the same position in the axial direction. In such a state, ironing of the inner surface of the drawn portion 20a by the ironed portion 3a formed on the punch 3 is backed up from the back side of the drawn portion 20a by the drawn portion 2a of the cylindrical mold 2. (Fig. 1 (c)).
(5) In addition, when retracting the tube end machining tool 1 ends the ironing of the diaphragm portion 20a inner surface of the tube end, also the thickness t ₂ of the throttle portion 20a obtained the same as the thickness t ₁ of the base pipe (FIG. 1 (d)).

As described above, according to the tube end drawing tool 1 according to the present invention, the cylindrical mold 2 having the drawing portion 2 a having the diameter d ₂ smaller than the outer diameter D ₂ of the elementary tube 20 on the inner surface, and the inner diameter of the elementary tube 20. a punch 3 with ironing portion 3a external diameter d ₁ is less than D ₁ to the outer surface, substantially the same position on the ironing portion 3a axial direction of the punch 3 and the drawn portion 2a of the cylindrical mold 2 The cylindrical mold 2 and the punch 3 are fixed concentrically via a compression spring 4.

As a result, it is possible to integrate the drive for moving the cylindrical mold 2 and the punch 3 forward or backward, and the work tool 1 is advanced and press-fitted into the tube end of the raw tube 20 to obtain an outer diameter. the drawing, and then in two steps of ironing a retracted allowed inside diameter is the narrowed portion 20a having a base tube 20 and the same thickness t ₂ is obtained.

Further, according to the tube end processing method according to the present invention, after the cylindrical mold 2 is press-fitted into the tube end portion of the base tube 20 and the outer surface is drawn while compressing the compression spring 4, withdrawn punch 3 having an outer diameter d ₁ is less ironing section 3a than the inner diameter D ₁ of the tube 20 to the outer surface, so that ironing the inner surface while extending said compression spring 4, the drawing of the tube end, the processing This is possible without increasing the thickness of the parts and without the labor and cost of processing.

  Next, a pipe end machining tool and a pipe end machining method using the same according to Embodiment 2 of the present invention for deforming the pipe end of the raw pipe will be described with reference to FIGS. 3 and 4. To do. FIG. 3 is a schematic process diagram for explaining the pipe end machining tool and the pipe end machining method using the same according to the second embodiment of the present invention in the order of steps, and FIG. FIG. 3B is a schematic cross-sectional view showing a state in which the pipe end machining tool is advanced to deform the pipe end, and FIG. 3C is a drawing of the pipe end machining tool retracted. FIG. 3D is a schematic cross-sectional view showing a state after finishing the processing, and FIG. 3D is a schematic cross-sectional view showing a state after finishing the processing. 4 is a cross-sectional view taken along the line YY in FIG.

  However, the difference between the second embodiment of the present invention and the first embodiment is that there is a difference in the processing content of the raw tube, and accordingly, the cylindrical mold and punch constituting the tube end processing tool are different. Although the shape also differs, the configuration is exactly the same as in the first embodiment except for these differences, so the same reference numerals are given to the same components as those in the first embodiment, and the differences will be described below. To do.

  That is, the pipe end machining tool 1 of the first embodiment is a tool for drawing a pipe end portion of a raw pipe, and as shown in FIG. Has a circular cross section, the tube end machining tool 11 of the second embodiment is a tool for deforming the tube end of the raw tube into a hexagonal cross section, and as shown in FIG. The cross section of the metal mold 12 has a circular cross section having a deformed drawing portion 12a on the inner peripheral surface of a hexagonal cavity 12c, and the cross section of the punch 13 also has a hexagonal ironing portion 13a on the outer peripheral surface. Yes.

  Needless to say, the tube end processing tool 11 is not limited to the one in which the tube end portion of the raw tube 20 is deformed into a hexagonal cross section, and any deformable cross section that can be processed, such as a quadrangular cross section, a pentagonal cross section, or a star cross section. What you have is possible.

When the tube end working tool 11 is retracted, the punch 13 irons the inner surface of the deformed drawn portion 20b machined into the raw tube 20 by the ironing portion 13a having a diagonal distance L1. This is a tool for making the processed wall thickness t _{2 the} same as the wall thickness t ₁ of the blank tube 20. Therefore, in order to make the thickness t ₂ of the deformed drawn portion 20 b after ironing the same as the thickness t _{1 of the} blank tube 20, the diagonal surface of the drawn portion 12 a of the cylindrical mold 12. and between the distance _{L 2} and the ironing part between the diagonal faces of 3a distance _{L 1} of the punch _13, it is important to form a dimensional relationship such that _{(L 2 -L 1) / 2} = t 1 .

A tube end machining method using the tube end machining tool 11 for performing such a deforming process according to the second embodiment of the present invention will be described in the order of steps.
(1) As in the first embodiment, first, the tube end machining tool 11 is placed on the tool side of a press machine (not shown).
The raw tube 20 is attached to the fixed pedestal side, and preparation for the pipe end profile processing is completed (FIG. 3A).
(2) Next, when the tube end working tool 11 is advanced, the inclined portion 12b formed on the inner surface of the cylindrical mold 12 comes into contact with the tube end of the element tube 20, and the tube end of the element tube 20 is Is compressed and deformed along the inclined portion 12b, and at the same time, the compression spring 14 is compressed.

(3) When the tube end working tool 11 is further advanced, a deformed drawn portion 20b is formed at the tube end along the deformed drawn portion 12a of the cylindrical mold 12 (FIG. 3B). .
(4) When the irregular drawing of a predetermined length is finished, the pipe end working tool 11 is moved backward. Then, the deformed drawing portion 20b comes into close contact with the deformed drawing processing portion 12a of the retreating cylindrical mold 12, and the cylindrical mold 12 is pulled, so that the compression spring 14 is gradually extended.

(5) The deformed drawing portion 12a of the cylindrical mold 12 and the ironing portion 12a of the punch 13 are restored to their original positions that are substantially the same position in the axial direction. In such a state, ironing of the inner surface of the deformed drawn portion 20b by the ironed portion 13a formed in the punch 13 is performed in a state where it is backed up from the back side of the deformed drawn portion 20b (FIG. 3C). .
(6) Further, when retracting the tube end machining tool 11 ends the ironing profiled aperture portion 20b the inner surface of the blank tube 20, profiled aperture portion 20b of the wall thickness t ₂ is also blank tube 20 the same wall as the thickness t ₁ is obtained (FIG. 3 (d)).

As described above, according to the tube end machining tool according to the present invention, a cylindrical mold 12 having an inner surface different profile drawn portion 12a and the raw tube cross section, the largest dimension than the inner diameter D ₁ of the said base pipe 20 The punch 13 having a small ironing portion 13a on the outer surface is arranged so that the deformed drawing portion 12a of the cylindrical mold 12 and the ironing portion 13a of the punch 13 are substantially in the same position in the axial direction. The cylindrical mold 12 and the punch 13 are concentrically fixed via a compression spring 14.

  With such a configuration, it is possible to integrate driving for moving the cylindrical mold 12 and the punch 13 forward or backward, and advance the processing tool 11 with respect to the tube end of the raw tube 20. The pipe end portion having a cross-sectional shape different from that of the raw pipe 20 without being thickened in two steps in which the outer diameter is deformed and then the outer diameter is deformed and then the inner diameter is reduced by retreating the inner diameter. Is obtained.

  On the other hand, according to the tube end processing method according to the present invention, after the cylindrical mold 12 is press-fitted into the tube end portion of the raw tube 20 and the outer surface is deformed while compressing the compression spring 14, Since the punch 13 having the ironing portion 13a on the outer surface is extracted and the inner surface is ironed while the compression spring 14 is extended, the pipe end portion can be deformed without increasing the thickness of the processing portion. It became possible to implement without cost.

  In the pipe end processing tool and the pipe end processing method using the same according to the present invention, the thickness of the drawn part or the deformed drawn part after drawing or deforming the pipe end is made equal to the thickness of the raw pipe. However, the wall thickness of the throttle part or the deformed throttle part does not necessarily need to be the same thickness as the raw pipe, and can be thicker or thinner than the thickness of the raw pipe, The wall thickness after pipe end processing is not limited. Moreover, the pipe end processing tool and the pipe end processing method using the same according to the present invention can be applied to processing an axial groove on the pipe end or obtaining a thickness accuracy after the pipe end processing.

BRIEF DESCRIPTION OF THE DRAWINGS It is a typical process diagram for demonstrating the pipe end processing tool which concerns on Embodiment 1 of this invention, and the pipe end processing method using the same in order of a process, Fig.1 (a) is a schematic which shows the state before a process start. 1B is a schematic cross-sectional view showing a state in which the pipe end working tool is advanced to draw the pipe end, and FIG. 1C is a drawing in which the pipe end working tool is moved backward. FIG. 1D is a schematic cross-sectional view showing a state after the processing is finished, and FIG. It is a cross-sectional view which shows the XX arrow of FIG. FIG. 3A is a schematic process diagram for explaining a pipe end machining tool and a pipe end machining method using the same according to Embodiment 2 of the present invention in the order of steps, and FIG. 3A is a schematic diagram illustrating a state before machining is started. 3 (b) is a schematic cross-sectional view showing a state in which the pipe end machining tool is advanced to deform the pipe end, and FIG. 3 (c) is a profile machining by retreating the pipe end machining tool. FIG. 3D is a schematic cross-sectional view showing a state after finishing the processing, and FIG. 3D is a schematic cross-sectional view showing a state after finishing the processing. It is a cross-sectional view showing the YY arrow of FIG. FIG. 5A is a schematic process diagram for explaining a pipe end processing method according to a conventional example, FIG. 5A is a schematic diagram showing a pipe end expansion process, and FIG. 5B is an expanded pipe end throttle. FIG. 5C is a schematic diagram showing a final process for forming an O-ring groove. FIG. 6A is a schematic process diagram for explaining a drawing method according to a conventional example, FIG. 6A is a schematic cross-sectional view showing a state before starting drawing, and FIG. 6B shows a state during drawing. FIG. 6C is a schematic sectional view showing a state after the drawing process is completed. FIGS. 7A and 7B are schematic process diagrams for explaining a modified cross-section processing method according to a conventional example, FIG. 7A is a schematic cross-sectional view showing a drawing process of a pipe end, and FIG. 7B is an inner surface ironing by a punch. FIG. 7C is a schematic cross-sectional view showing the final step of retracting the drawing die.

Explanation of symbols

D ₁ : Inner pipe inner diameter D ₂ : Outer pipe outer diameter d ₁ : Punch ironing part outer diameter, d ₂ : Punch ironing part inner diameter L ₁ : Punch ironing part diagonal distance L ₂ : Distance between diagonally-drawn portions of the cylindrical mold t ₁ : Thickness of the raw tube, t ₂ : Thickness of the processed portion 1: Pipe end processing tool (tube end drawing tool)
2: cylindrical mold, 2a: drawing part, 2b: inclined surface, 2c: hollow part 3: punch, 3a: ironing part 4, 14: compression spring, 5, 15: pedestal,
11: Pipe end machining tool (pipe end irregular drawing tool)
12: Cylindrical mold, 12a: Deformed drawing part, 12b: Inclined part 13: Punch, 13a: Ironing part,
20: Elementary tube, 20a: Restriction part, 20b: Deformed restriction part

Claims (3)

  In a pipe end processing tool for drawing a pipe end of an element pipe, a cylindrical mold having an inner diameter of a drawing part smaller than the outer diameter of the element pipe, and an outer diameter smaller than the inner diameter of the element pipe A punch having an ironing portion on the outer surface is disposed so that the drawing portion of the cylindrical mold and the ironing portion of the punch are substantially in the same position in the axial direction, and the cylindrical die and the punch A tube end processing tool characterized in that the tube end is fixed concentrically through a compression spring.   In a tube end machining tool for deforming a tube end of a raw tube, a cylindrical mold having a deformed drawing portion on the inner surface, which is different from the cross-sectional shape of the raw tube, and an outermost dimension from the inner diameter of the raw tube A punch having a small ironing part on the outer surface thereof, and the deformed drawing part of the cylindrical mold and the ironing part of the punch are arranged at substantially the same position in the axial direction, and the cylindrical die And a punch are fixed concentrically through a compression spring.   Using the pipe end processing tool according to claim 1 or 2, the cylindrical mold is press-fitted into the pipe end of the base pipe, and the outer surface is drawn or deformed while compressing the compression spring. Thereafter, a pipe end machining method comprising: extracting a punch having an ironing portion having an outer dimension smaller than an inner diameter of the raw tube on an outer surface, and extending the compression spring to iron the inner surface of the machining portion.

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