JP2586436B2 - Manufacturing method of double-ended cylinder with one end closed - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a double-ended cylinder having a closed-end type in which an outer cylinder and an inner cylinder are closed at one end by forging.

[0002]

2. Description of the Related Art For example, as a component constituting a main body of a receiver of a refrigeration cycle, a double-ended cylinder 21 having a closed end as shown in FIG. 16 is used. The conventional one-end closed type double cylinder 21 is fixed by caulking an inner cylinder 24 of another piece to the bottom 23 of the outer cylinder 22.

In this configuration, the work of caulking the outer cylinder 22 and the inner cylinder 24 is troublesome, which not only causes a decrease in productivity, but also may cause poor caulking. This also had an adverse effect on the reliability of the bonding strength with H.24.

Therefore, as disclosed in Japanese Utility Model Laid-Open No. 5067/1988, it has been considered to integrally form an outer cylinder and an inner cylinder.

[0005]

There are two methods for integrally molding the outer cylinder and the inner cylinder with a metal material, namely, casting (casting molding) and forging. Since properties (such as strength) are deteriorated, it is not suitable for manufacturing a thin double cylinder.

On the other hand, forging is superior in mechanical properties (strength, etc.) of the product as compared with casting, and the present inventor believes that forging is suitable for manufacturing a thin double cylinder. .

Therefore, the present inventor has repeated many experiments in order to develop a technique for integrally forging an outer cylinder and an inner cylinder from one metal material. Even if an attempt is made to forge the outer cylinder and the inner cylinder integrally from one metal material, the plastic flow direction of the metal material during forging is biased to either the inner cylinder side or the outer cylinder side, and the outer cylinder and the inner cylinder are Length ratio is not as designed. For this reason, conventionally, at most, only the outer cylinder can be forged as a single item, and an inner cylinder of another piece is caulked to this outer cylinder. As described above, in this configuration, the productivity is reduced and the coupling strength between the inner cylinder and the outer cylinder is reduced.

The present invention has been made in view of such circumstances, and an object of the present invention is to be able to efficiently manufacture a double-ended cylinder having a one-end closed type from a single metal material by forging. It is an object of the present invention to provide a method of manufacturing a double-ended cylinder with one end closed, which can set the length ratio as desired.

[0009]

According to the present invention, a method of manufacturing a double-ended cylinder closed at one end is to forging a double-ended cylinder closed at one end between an outer cylinder and an inner cylinder positioned inside the outer cylinder. When integrally molding by using a die having a molding concave portion, a cylindrical punch, and a center pin arranged on a center line of the cylindrical punch, a metal material is stored in the molding concave portion of the die, Is pressurized by the cylindrical punch, whereby the metal material is plastically flowed into a gap between the molding concave portion of the die and the cylindrical punch and a gap between the cylindrical punch and the center pin, and the outside is formed. A method of forming a cylinder and the inner cylinder, wherein the metal punch is formed by using, as the cylindrical punch, a cylindrical punch having a tapered surface having a predetermined slope with a vertex at a predetermined position of a tip pressing portion thereof. Material is on the outer cylinder side The position of the watershed when plastically flowing to the inner cylinder side is regulated by the apex or the gradient angle of the tapered surface, and the length ratio between the inner cylinder and the outer cylinder is set as desired. (Claim 1).

In this case, the position of the watershed is determined by the length of the land by using a cylindrical punch having a land of a predetermined length ratio formed on the inner peripheral surface and the outer peripheral surface on the distal end side as the cylindrical punch. The length ratio between the inner cylinder and the outer cylinder may be set as desired by regulating the ratio.

[0011]

According to the manufacturing method of the present invention, the metal material housed in the molding recess of the die is pressed by the cylindrical punch,
The outer cylinder and the inner cylinder are formed by plastically flowing a metal material into a gap between the molding concave portion of the die and the cylindrical punch and a gap between the cylindrical punch and the center pin.

[0012] At this time, when forging is performed using a cylindrical punch having a tapered surface with a predetermined slope having a vertex at a predetermined position of a tip pressing portion as the cylindrical punch, The position of the watershed when the material plastically flows to the outer cylinder side and the inner cylinder side is regulated by the apex or the slope angle of the tapered surface. Since the length ratio between the inner cylinder and the outer cylinder is determined by the position of the watershed, the position of the vertex of the tapered surface that regulates the position of the watershed so that the length ratio between the outer cylinder and the inner cylinder becomes a desired value. Alternatively, the gradient angle may be determined.

According to a second aspect of the present invention, when the cylindrical punch is formed by forging using a cylindrical punch having a land of a predetermined length ratio formed on an inner peripheral surface and an outer peripheral surface on a tip side thereof,
The position of the watershed is regulated by the length ratio (friction area ratio) of the land. Also in this case, the length ratio of the land that regulates the position of the watershed may be determined so that the length ratio between the inner cylinder and the outer cylinder becomes a desired value.

Incidentally, both the tapered surface and the land are provided on one cylindrical punch, and the position of the watershed (the length of the outer cylinder and the inner cylinder is determined by the combination of the position of the vertex of the tapered surface and the length ratio of the land). Needless to say, the ratio may be regulated.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. First, the configuration of the double-ended one-end cylinder 31 manufactured by the manufacturing method of the first embodiment will be described with reference to FIG. One end closed type double cylinder 31 is a thin outer cylinder 3
2 and the thin inner cylinder 33 located at the center thereof
4 forged together. In this case, both ends of the inner cylinder 33 are open (a through-hole 33 a penetrating through the inner cylinder 33 is formed in the closing portion 34), but the outer cylinder 32
The gap between the inner cylinder 33 and the inner cylinder 33 is closed at one end by a closing portion 34.

As a raw material for forging the double-ended cylinder 31 with closed one end, a metal material 35 (see FIG. 3) having excellent plastic deformability (forging workability) such as an aluminum alloy (A3004) is used. The shape of the metal material 35 is, for example, a thick short cylindrical shape, and a through hole 35a is formed at the center thereof.

Next, the structure of a forging device 36 for cold forging the double-ended cylinder 31 with one end closed from the metal material 35 will be described with reference to FIG. The combination of the upper die 37 and the lower die 38 forms a molded concave portion 39 for accommodating the thick and short cylindrical metal material 35. The height of the molding recess 39 is higher than the height of the metal material 35.

A center pin 40 is fixed to the lower die 38 in an upward direction.
Projecting upward at the center. The outer diameter of the projecting portion of the center pin 40 is the same as the inner diameter of the inner cylinder 33. A through hole 35 of a metal material 35 is
The inner diameter of the through-hole 35a is formed slightly larger than the outer diameter of the protruding portion of the center pin 40 in order to fit a. Further, the projecting height of the center pin 40 is higher than the height of the metal material 35. Also, the lower die 38
Is provided with a knockout pin 41 for pushing out a forged product from the molding recess 39 after forging is completed.

On the other hand, the cylindrical punch 42 is supported by a press (not shown) so as to be vertically movable, and is arranged coaxially with the center pin 40. As shown in FIG. 2, lands 43 and 44 having a predetermined length ratio are formed on the inner peripheral surface and the outer peripheral surface on the distal end side (lower end side) of the cylindrical punch 42. Are formed with tapered surfaces 46 and 47 each having a vertex 45 at a predetermined position.

In this case, the gap between the land 44 on the outer peripheral side and the molding recess 39 is set to be the same as the thickness of the outer cylinder 32, and the gap between the land 43 on the inner peripheral side and the center pin 40 is The thickness is set equal to the thickness of the inner cylinder 33. At the time of cold forging, the metal material 35 housed in the forming recess 39 is pressed by the cylindrical punch 42 to thereby form a gap between the forming recess 39 and the land 43 of the cylindrical punch 42 and the cylindrical punch 42.
The outer cylinder 32 and the inner cylinder 33 are formed by plastically flowing the metal material 35 into the gap between the land 44 and the center pin 40 as shown by a white arrow in FIG.

Incidentally, when cold forging the double-ended cylinder 31 with one end closed as in the present embodiment, a water diversion 48 always occurs in the closed portion 34 between the inner cylinder 33 and the outer cylinder 32. here,
The watershed 48 is a branch point in the flow direction when the metal material 35 plastically flows to the outer cylinder 32 side and the inner cylinder 33 side as shown by a white arrow in FIG. Is the point at which is zero.

The length ratio (Hin / Hout) of the inner cylinder 33 and the outer cylinder 32 changes depending on the position of the watershed 48 (FIG. 4).
reference). That is, as the position of the watershed 48 shifts toward the inner peripheral side, the amount of material plastically flowing toward the outer cylinder 32 increases, and the height of the outer cylinder 32 increases (Hin / Hout decreases). Conversely, as the position of the watershed 48 shifts toward the outer peripheral side, the amount of material plastically flowing toward the inner cylinder 33 increases, and the height of the inner cylinder 33 increases (Hin / Hout increases).

In this case, the length ratio between the inner cylinder 33 and the outer cylinder 32 is the ratio of the cross-sectional area Ain of the inner cylinder 33 and the cross-sectional area Aout of the outer cylinder 32 to the cross-sectional area Aall of the metal material 35 (A
in / Aall, Aout / Aall) and the wall thickness ratio, but it is generally impossible to find the area ratio and wall thickness ratio that makes the length ratio between the inner cylinder 33 and the outer cylinder 32 desired. It's not easy. In addition, if the area ratio and the wall thickness ratio are changed, the mechanical characteristics (strength, heat transfer characteristics, etc.) of the forged product will change, and the weight of the forged product will increase due to the excess wall thickness. There is also.

Therefore, in this embodiment, the inner cylinder 33 and the outer cylinder 3
The setting of the length ratio to 2 is performed by adjusting the position of the watershed 48 without changing the area ratio and the wall thickness ratio. In this case, as a method of regulating the position of the watershed 48 to a predetermined position, a method of adjusting the position or the inclination angle of the apex 45 of the tapered surfaces 46 and 47, a method of adjusting the length Lin and the outer periphery of the land 43 on the inner peripheral side. The ratio of the land 44 to the length Lout (L
in / Lout), there are two ways to adjust
In this embodiment, the position of the watershed 48 is regulated to a predetermined position by combining these two methods.

That is, in this embodiment, the tapered surfaces 46, 47
Of the watershed 48 by setting the position or gradient angle of the vertex 45 of the lands 43 and the length ratio (Lin / Lout) of the lands 43 and 44 to conditions determined in advance by experiments, calculations, and the like. Length ratio between the cylinder 33 and the outer cylinder 32 (Hin / H
out) is set as desired (experimental data relating to this will be described later).

For example, when the heights of the inner cylinder 33 and the outer cylinder 32 are the same, the watershed 48 must be located at a radius r1 such that Ain / Ar1 = Aout / Ar2-r1. Here, Ar1 is a cross-sectional area of the closed portion 34 in a region within the radius r1, and Ar2-r1 is a cross-sectional area of the closed portion 34 in a region outside the radius r1.

When the inner cylinder 33 is higher than the outer cylinder 32, the position of the watershed 48 is shifted to the outside of the radius r1, and when the outer cylinder 32 is higher than the inner cylinder 33, The position of the watershed 48 may be shifted inward from the radius r1.

On the other hand, the cross sectional area Ain of the inner cylinder 33 and the outer cylinder 32
When the area ratio Ain / Aout with respect to the cross-sectional area Aout is reduced, the watershed 48 moves inward, and conversely, Ain / Aou
Increasing t moves watershed 48 outward.

The length ratio of the lands 43 and 44 (Lin /
Lout), the ratio of the contact area (frictional force) between the material and the lands 43 and 44 when the metal material 35 plastically flows between the outer cylinder 32 and the inner cylinder 33 during cold forging changes. The resistance of the plastic flow changes, and the position of the watershed 48 moves. In this case, the smaller Lin / Lout is, the more the inner cylinder 3
The plastic flow to the third side increases, and the watershed 48 moves outward. Conversely, as Lin / Lout increases, the outer cylinder 32 increases.
The plastic flow to the side increases, and the watershed 48 tends to move inward.

FIG. 5 shows experimental data for explaining this relationship. This experimental data shows that the length Lout of the land 44 on the outer peripheral side is fixed to 1.7 mm, and the length of the inner cylinder 33 and the outer cylinder 32 when the length Lin of the land 43 on the inner peripheral side is changed. It shows a change in the ratio (Hin / Hout). The cylindrical punch used in this experiment had no tapered surface as shown in FIG. 11 (the inner diameter and outer diameter of this cylindrical punch were 7.5 mm and 56.8 mm, respectively, and the center pin 4 was used).
0 has an outer diameter of 7.5 mm, and the inner diameter of the molding recess 39 of the dies 37 and 38 is 60 mm).

In general, the position of the watershed 48 is the tapered surface 4
It is desirable to be at or near the vertex 45 of the vertices 6, 47, but it is also possible to deliberately shift by adjusting the length ratio of the lands 43, 44 and the gradient angle of the tapered surfaces 46, 47 described above. is there. For example, as the gradient angle of the inner peripheral side tapered surface 46 is increased, the plastic flow toward the inner cylinder 33 increases, and the watershed 48 moves outward.
As the inclination angle of the tapered surface 47 on the outer peripheral side is increased, the plastic flow toward the outer cylinder 32 increases, and the watershed 48 tends to move inward.

FIG. 6 shows experimental data for explaining this relationship. This experimental data shows a change in the length ratio (Hin / Hout) between the inner cylinder 33 and the outer cylinder 32 when the gradient angle of the outer peripheral side tapered surface 47 is changed. As shown in FIG. 9, the cylindrical punch used in this experiment had no tapered surface on the inner peripheral side, and had a length L of the land 43 on the inner peripheral side.
in is 20 mm, and the length Lout of the land 44 on the outer peripheral side is 1.
7 mm and the vertex 45 of the tapered surface 47 on the outer peripheral side is located at a position having a radius of 8.8 mm from the center. The metal materials 35 used in this experiment were of two types, a height of 39 mm and a height of 35 mm (both having a diameter of 59 m).
m). From the experimental data of FIG.
It can be seen that the length ratio (Hin / Hout) varies with the gradient angle of the tapered surface 47 and the height of the metal material 35.

Next, a procedure for cold forging the double-ended cylinder 31 with the closed one end using the forging device 36 will be described. First, as shown in FIG.
Is set, and the through hole 35 a of the metal material 35 is set in a state of being fitted into the center pin 40. Thereafter, the cylindrical punch 42 is lowered by a press machine (not shown), and the distal end pressing portions (tapered surfaces 46, 47) of the cylindrical punch 42 are pressed against the metal material 35, and the metal material 35 is removed. It is compressed so as to be crushed in the molding recess 39. As a result, the metal material 35 is separated from the metal recess 35 by the watershed 48 in the molding recess 39 as shown in FIG.
Plastic flows in the directions opposite to each other as shown by the white arrows, and the gap between the molding recess 39 and the land 43 of the cylindrical punch 42 and the land 44 of the cylindrical punch 42 and the center pin 4
The metal material 35 is extruded into the gap between the outer cylinder 32 and the outer cylinder 32.
And the inner cylinder 33 are formed integrally with the closing portion 34. This forged product (one-end closed double cylinder 31) is projected from the molding recess 39 by the knockout pin 41 after the forging is completed.
Incidentally, the forged product is stuck to the cylindrical punch 42 to form the molding recess 39.
However, in this case, the forged product is removed from the cylindrical punch 42 by a removing means (not shown).

When the double cylinder 31 with one end closed, which is cold forged in this way, is used as the receiver body 49 (a component of the refrigeration cycle) shown in FIGS. 7 and 8, the inner cylinder 33 is used.
Is required to be about 0 to 20 mm shorter than the length Hout of the outer cylinder 32 so that Hin / Hout = 0.9 to 1.0.

For example, when forging a cross-sectional area ratio (Ain / Aout) of the inner cylinder 33 and the outer cylinder 32 of 0.091, a cylindrical punch having no tapered surface at the tip (land length ratio = 1.0), Hin / Hout = 1.
4 to 1.6, and a forged product having a desired size cannot be obtained.

On the other hand, when the cylindrical punch 50 of the second embodiment of the present invention shown in FIG.
Is set at a position having a radius of 8.8 mm from the center, the slope angle of the tapered surface 47 is 7 °, the length Lin of the inner land 43 is 20 mm, and the length of the outer land 44 is When processed using a material with Lout of 1.7 mm,
A forged product having desired dimensions such that /Hout=0.9 to 1.0 was obtained. However, this is the case where Hin = 235 mm.
When Hin = 195 mm, it is appropriate to set the inclination angle of the tapered surface 47 to 13 °.

The cylindrical punch 50 shown in FIG. 9 has no tapered surface on the inner peripheral side, and the inner peripheral side from the vertex 45 is flat.
As shown in FIG. 2, even if machining is performed using a cylindrical punch 42 having a tapered surface 46 also formed on the inner peripheral side from the vertex 45,
If the position and the gradient angle of 5 are set in advance to conditions determined by experiments, calculations, and the like, a forged product having desired dimensions can be obtained.

Also, as in the third embodiment of the present invention shown in FIG. 10, machining may be performed using a cylindrical punch 51 having no tapered surface on the outer peripheral side and having a flat outer peripheral side from the vertex 45. Needless to say.

Further, as in the fourth and fifth embodiments of the present invention shown in FIGS. 11 and 12, processing may be performed by using cylindrical punches 52 and 53 having a flat pressing portion at the tip. . Even in this case, the length ratio of the lands 43 and 44 (Lin / Lout)
Is set to a condition determined in advance by experiments, calculations, or the like, thereby restricting the position of the watershed 48 and setting the length ratio (Hin / Hout) between the inner cylinder 33 and the outer cylinder 32 as desired. It is possible. In the cylindrical punch 52 of FIG. 11, the land 43 on the inner peripheral side is longer than the land 44 on the outer peripheral side, and in the cylindrical punch 53 of FIG. 12, the land 44 on the outer peripheral side is larger than the land 43 on the inner peripheral side. It is getting longer.

One end closed double cylinder 31 cold-forged using any of the above-described cylindrical punches 42, 50 to 53
Is used, for example, as a receiver body 49 (a component of a refrigeration cycle) shown in FIGS. 7 and 8. In the receiver body 49, the opening end side of the outer cylinder 32 is formed by drawing into a small diameter, and a dome-shaped lid 54 is welded to the opening end. A gap for refrigerant circulation is secured between the lid 54 and the tip of the inner cylinder 33. In the receiver main body 49, the desiccant 55 has a felt 5 serving as a filter.
6, 57 and the perforated plates 58, 59. Each of the perforated plates 58 and 59 is caulked to the inner cylinder 33 and the outer cylinder 32. As shown in FIG. 8, the closing portion 34 of the receiver main body 49 is provided with the refrigerant inlet 6 by post-processing.
0, screw holes 61 and 62 and positioning holes 63 and 64 are formed.

The forging device 36 of the first embodiment described above.
Although the center pin 40 is fixed to the lower die 38, the center pin 66 may be fixed in the cylindrical punch 42 as in a forging device 65 of a sixth embodiment of the present invention shown in FIG. . In this case, the length of the center pin 66 needs to be longer than the lower end of the cylindrical punch 42 by at least the height of the metal material 35. Therefore, at the time of forging, the lower end portion of the center pin 66 is fitted into the fitting hole 38a formed in the center of the lower die 38.

Further, the center pins 40,
66 are configured to penetrate through holes 35a of the metal material 35. However, like the forging device 67 of the seventh embodiment of the present invention shown in FIGS.
8 may not penetrate the metal material 69. Also in this case, the center pin 68 is fixed in the cylindrical punch 42. The length (lower end position) of the center pin 68 is substantially the same as the length (lower end position) of the cylindrical punch 42, and both the lower end of the center pin 68 and the metal material 69 are used during forging. Will be compressed as if crushed. The metal material 69 housed in the forming recess 39 of the forging device 67 may have a short columnar shape as shown in FIG. 15, and a central through hole is not required.

The double-ended cylinder 70 closed at one end by the forging device 67 has a shape in which the lower end of the inner cylinder 33 is also closed by the closing portion 71. Accordingly, this one-end closed double cylinder 70
Is used as the receiver body 49 shown in FIGS. 7 and 8, a hole is formed in the center of the closing portion 71,
A through hole penetrating through the lower end of the inner cylinder 33 will be formed.

The metal material 3 used in each of the embodiments described above.
5, 69 are not limited to aluminum alloys, and other metal materials having excellent plastic deformability (forging workability) such as copper and low carbon steel may be used. Further, as in the first to third embodiments, when the tapered surfaces 46 and 47 are formed at the tip pressing portions of the cylindrical punches 42, 50 and 51, the lands 43 and
The length ratio (Lin / Lout) of 44 may be 1.0. This is because the position of the watershed 48 can be regulated by the position of the vertex 45 of the tapered surfaces 46 and 47 and the inclination angle thereof.

In addition, it goes without saying that the present invention can be carried out in various modifications without departing from the gist of the invention, for example, the use of the forged double-ended cylinders 31, 70 is not limited to the receiver body 49.

[0046]

As is apparent from the above description, the present invention is directed to a cylindrical punch used for forging, in which a tapered surface having a predetermined slope with a vertex is formed at a predetermined position of a tip pressing portion. Alternatively, a closed-type double cylinder is forged using a cylindrical punch in which lands having a predetermined length ratio are formed on the inner peripheral surface and the outer peripheral surface on the distal end side. The closed double cylinder can be efficiently manufactured by forging, and the position of the watershed can be regulated by the position of the apex of the tapered surface or the inclination angle or the length ratio of the land, so that the outer cylinder and the inner cylinder can be connected to each other. An excellent effect that the length ratio can be set as desired is achieved.

[Brief description of the drawings]

FIG. 1 shows a forging device according to a first embodiment of the present invention;
(A) is a longitudinal sectional view showing a stored state of a metal material before forging,
(B) is a longitudinal sectional view showing a state at the time of forging.

FIG. 2 is a vertical cross-sectional view around a tip pressing portion of a cylindrical punch.

FIG. 3 is a perspective view of a metal material.

FIG. 4 is a longitudinal sectional view of a forged one-end closed type double cylinder.

FIG. 5 is a change characteristic diagram of a length ratio of an inner cylinder and an outer cylinder to a length of a land on the inner cylinder side.

FIG. 6 is a characteristic diagram of a change in the length ratio of the inner cylinder and the outer cylinder with respect to the inclination angle of the tapered surface.

FIG. 7 is a longitudinal sectional view of the receiver, taken along the line VII-VII in FIG. 8;

FIG. 8 is a top view of a receiver.

FIG. 9 is a vertical cross-sectional view around a pressing portion at the tip end of a cylindrical punch showing a second embodiment of the present invention.

FIG. 10 is a vertical cross-sectional view of a portion around a tip pressing portion of a cylindrical punch showing a third embodiment of the present invention.

FIG. 11 is a vertical cross-sectional view of a portion around a tip pressing portion of a cylindrical punch showing a fourth embodiment of the present invention.

FIG. 12 is a vertical cross-sectional view showing the vicinity of a tip pressing portion of a cylindrical punch showing a fifth embodiment of the present invention.

FIG. 13 is a longitudinal sectional view of a forging device showing a sixth embodiment of the present invention.

FIG. 14 is a vertical cross-sectional view around a pressing portion at the tip end of a cylindrical punch showing a seventh embodiment of the present invention.

FIG. 15 is a perspective view of a metal material used in a seventh embodiment of the present invention.

FIG. 16 is a longitudinal sectional view of a conventional double-ended cylinder with one end closed.

[Explanation of symbols]

31 is a double cylinder with a closed end, 32 is an outer cylinder, 33 is an inner cylinder, 3
4 is a closed portion, 35 is a metal material, 36 is a forging device, 37 is an upper die, 38 is a lower die, 39 is a molding concave portion, 40 is a center pin, 41 is a knockout pin, 42 is a cylindrical punch,
3 and 44 are lands, 45 is an apex, 46 and 47 are tapered surfaces, 48 is a watershed, 49 is a receiver body, 50 to 53
Is a cylindrical punch, 65 is a forging device, 66 is a center pin, 6
7 is a forging device, 68 is a center pin, 69 is a metal material, 7
Reference numeral 0 denotes a double-ended double-ended cylinder, and 71 denotes a closed portion.

 ──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Tokuo Shirai 1-1-1 Showa-cho, Kariya-shi, Aichi Japan Inside Denso Co., Ltd. (56) References JP-A-1-215427 (JP, A) JP-A-63- 149037 (JP, A) JP-A-2-29938 (JP, A) JP-A 1-227139 (JP, U) JP-A 1-5067 (JP, U) JP-B 37-6621 (JP, B1) JP-B48-9259 (JP, B1)

Claims (2)

(57) [Claims] 1. A die having a molded concave portion, a cylindrical punch, and a die having a molded concave portion when integrally forming a double-ended cylinder closed at one end by closing between an outer cylinder and an inner cylinder positioned inside the outer cylinder. By using a center pin arranged on the center line of the cylindrical punch, a metal material is housed in the forming recess of the die, and the metal material is pressed by the cylindrical punch, so that the forming recess of the die and the A method of forming the outer cylinder and the inner cylinder by plastically flowing the metal material into a gap between the cylindrical punch and a gap between the cylindrical punch and the center pin, wherein the outer cylinder and the inner cylinder are formed. By using a cylindrical punch formed with a tapered surface having a predetermined slope with a vertex at a predetermined position of the tip pressing portion, the metal material flows plastically to the outer cylinder side and the inner cylinder side. The position of the watershed is tapered A method for manufacturing a double-ended cylinder with one end closed, wherein a length ratio between the inner cylinder and the outer cylinder is set to a desired value by restricting a vertex or a slope angle of a surface. 2. A die having a molded concave portion, a cylindrical punch, and a die for integrally forming a double-ended cylinder closed at one end by forging a closed end between an outer cylinder and an inner cylinder positioned inside the outer cylinder. By using a center pin arranged on the center line of the cylindrical punch, a metal material is housed in the forming recess of the die, and the metal material is pressed by the cylindrical punch, so that the forming recess of the die and the A method of forming the outer cylinder and the inner cylinder by plastically flowing the metal material into a gap between the cylindrical punch and a gap between the cylindrical punch and the center pin, wherein the outer cylinder and the inner cylinder are formed. By using a cylindrical punch in which lands of a predetermined length ratio are formed on the inner peripheral surface and the outer peripheral surface on the tip side, when the metal material plastically flows to the outer cylinder side and the inner cylinder side, The position of the watershed is the length of the land A method for manufacturing a double-ended cylinder with one end closed, wherein a length ratio between the inner cylinder and the outer cylinder is set as desired by regulating the length ratio.