JP5938264B2 - Manufacturing method for hollow products - Google Patents

Description

  The present invention relates to a method for manufacturing a hollow article, and more particularly, to a method for forging a hollow article having a stepped outer peripheral surface.

  Conventionally, as a method of manufacturing a hollow product, a large diameter portion and a small diameter portion are formed on the outer peripheral surface, a step is formed between the large diameter portion and the small diameter portion, and a hollow portion having both ends in the axial direction is open. 7 is known.

  In this manufacturing method, first, a material (blank) 101 made of a metal pipe having a hollow 101a having a constant outer diameter and a constant inner diameter in the axial direction is shown in FIG. The first hole 102 having substantially the same diameter as the outer diameter of the large diameter portion of the material 101, and the second hole 103 having a diameter smaller than the inner diameter of the first hole 102 are continuously formed below the first hole 102. Placed in the dice 104.

  Next, as shown in FIG. 7B, the cored bar 105 and the sleeve punch 106 are moved in the direction of the die 104 from above the material 101, and the cored bar 105 is inserted into the hollow 101 a of the material 101, As shown in FIG. 7C, the front punching process in which the material 101 is pushed in the direction of the second hole 103 by the sleeve punch 106 and the material 101 is plastically flowed in the direction of the second hole 103 that is the traveling direction of the sleeve punch 106. To reduce the outer surface of the lower part of the material 101 and manufacture a stepped hollow article 107 having a step formed on the outer peripheral surface (see, for example, Patent Document 1).

Japanese Examined Patent Publication No. 2-6412

  In the conventional manufacturing method, as shown in FIG. 7 (b), the cored bar 105 is inserted so as to protrude from the lower end opening of the hollow 101a, and as shown in FIG. When processing, the axial length of the cored bar 105 is set so that the cored bar 105 is arranged over the entire axial direction of the hollow 101a.

  Therefore, in the case of manufacturing a hollow product 110 having a large L / D that is an axial length (full length) L with respect to the diameter D of the hollow portion in the hollow product to be manufactured, as shown in FIG. It is necessary to lengthen the axial length of the gold 105. However, if the length of the cored bar 105 is increased, the contact area between the cored bar 105 and the material 101 increases, and the frictional force increases. Therefore, the life of the cored bar 105 is shortened because the cored bar 105 is broken early. There is a risk of becoming.

  Therefore, an object of the present invention is to provide a method for manufacturing a hollow article that can extend the life of the cored bar as compared with the manufacturing method of the prior art.

In order to solve the above-described problems, a method for manufacturing a hollow article according to the present invention uses a sleeve punch, a cored bar inserted into the sleeve punch, and a die, and a material having a hollow portion that is open at both ends. In the method for producing a hollow product having a hollow portion that is open at both ends, by forming the outer peripheral surface into a stepped shape by performing forward extrusion processing,
By providing a plurality of the sleeve punches and adding the sleeve punches in stages, the amount of protrusion of the core bar protruding from the tip of the sleeve punch at the time of forward extrusion is reduced in stages while being reduced in stages. A hollow product is manufactured in stages by performing forward extrusion processing.

  Further, at least one of reciprocating the sleeve punch and the cored bar a plurality of times, another cored bar is inserted into the hollow part from the opening on the material opposite to the cored bar. It may be.

  According to the present invention, the forward extrusion process is performed a plurality of times while the amount of protrusion of the core metal protruding from the tip of the sleeve punch at the time of the forward extrusion process is reduced stepwise, and a hollow product is manufactured stepwise. As a result, when manufacturing a hollow product having a large L / D, the length of the cored bar can be made shorter than the conventional manufacturing method, and the frictional force between the cored bar and the material can be reduced. , Can extend the life of the cored bar.

The front view of the manufacturing apparatus used for Example 1 of this invention. The figure explaining the 1st process of the manufacturing method of the hollow goods which concern on Example 1 of this invention. The figure explaining the 2nd process of the manufacturing method of the hollow goods which concern on Example 1 of this invention. The figure explaining the 2nd process of the manufacturing method of the hollow goods which concern on Example 2 of this invention. The figure explaining the 2nd process of the manufacturing method of the hollow goods which concern on Example 3 of this invention. The figure explaining the 2nd process of the manufacturing method of the hollow goods which concern on Example 4 of this invention. The figure explaining the manufacturing method of the conventional hollow goods.

A mode for carrying out the present invention will be described based on an embodiment shown in the drawings.
[Example 1]
1 to 3 show a first embodiment of the present invention.

First, the manufacturing apparatus 1 used for the manufacturing method of the hollow goods of this invention is demonstrated.
As shown in FIG. 1, the manufacturing apparatus 1 includes an upper base 2A and a lower base 2B, and the upper base 2A and the lower base 2B are changed by a moving means (not shown) so that the relative distance thereof changes. It can be moved. In the present embodiment, the lower base 2B is fixed, and the relative distance with respect to the lower base 2B can be changed by moving the upper base 2A in the vertical direction in FIG. It is like that. In the following description, the vertical direction in FIG.

  As shown in FIG. 1, the upper base 2 </ b> A includes a first sleeve punch 3, a first core metal 4 inserted into the hollow portion 3 a of the first sleeve punch 3, and a second sleeve punch 5. A second cored bar 6 inserted into the hollow portion 5a of the second sleeve punch 5 is provided, and a die 7 is provided on the lower base 2B.

  The first sleeve punch 3 and the first core metal 4, the second sleeve punch 5 and the second core metal 6 are reciprocated in the left-right direction by a moving means (not shown), for example, an air cylinder, The axis X1 of the first metal core 4 or the axis X2 of the second sleeve punch 5 and the second metal core 6 and the axis X3 of the die 7 can be matched.

  The first sleeve punch 3 and the first metal core 4 are connected to different moving means (not shown), for example, cylinders, and the first metal core with respect to the first sleeve punch 3 in the X1 direction (vertical direction). 4 can move relatively. Further, the second sleeve punch 5 and the second cored bar 6 are also connected to different moving means (not shown), for example, cylinders, and are second to the second sleeve punch 5 in the axis X2 direction (vertical direction). The cored bar 6 can move relatively.

  The first sleeve punch 3 has a hollow portion 3a into which the first cored bar 4 can be inserted, and the lower end of the hollow portion 3a is open. The lower end surface of the first sleeve punch 3 is formed in a shape corresponding to the shape of the upper end of the material 11.

  The second sleeve punch 5 has a hollow portion 5a into which the second cored bar 6 can be inserted, and the lower end of the hollow portion 5a is open. The lower end surface of the second sleeve punch 5 is formed in a shape corresponding to the shape of the upper end of the material 11.

  The first core metal 4 has a predetermined length, and the outer peripheral shape thereof is formed in a shape corresponding to the hollow portion 25a of the hollow product 25 to be manufactured (see FIG. 3). The first metal core 4 is inserted into the hollow portion 3 a of the first sleeve punch 3 so that it can slide with respect to the first sleeve punch 3.

  As shown in FIG. 1, the second metal core 6 has the same length as the first metal core 4, and the outer peripheral shape thereof is formed in a shape corresponding to the hollow portion 25 a of the hollow article 25 to be manufactured, The second sleeve punch 5 is inserted into the hollow portion 5 a so that it can slide with respect to the second sleeve punch 5.

  As shown in FIG. 1, the length of the first sleeve punch 3 in the vertical direction (axis X1 direction) is set to be shorter than the length of the second sleeve punch 5 in the vertical direction. Since the lengths of the cored bar 6 are set to be the same, the maximum protruding amount of the first cored bar 4 from the lower end of the first sleeve punch 3 is the second cored bar 6 from the lower end of the second sleeve punch 5. It is longer than the maximum protruding amount.

  As shown in FIGS. 1 to 3, the die 7 has a large-diameter portion 12 having an inner wall formed in a shape corresponding to the outer shape of the material 11. A reduced diameter portion 13 is provided at the lower portion of the large diameter portion 12 so that the diameter decreases from the inner diameter of the lower end of the large diameter portion 12 toward the lower side. A small-diameter portion 14 having an inner wall formed in a shape corresponding to the outer surface of the hollow article 25 to be manufactured is provided. The large-diameter portion 12, the reduced-diameter portion 13, and the small-diameter portion 14 are continuously formed, and the respective central axes are formed on the same line X3.

Next, the manufacturing method of the hollow goods of this invention is demonstrated.
(First step)
First, as shown in FIGS. 1 and 2, the axis X <b> 1 of the first sleeve punch 3 and the first metal core 4 is moved to the axis of the large-diameter portion 12 of the die 7 by a moving operation using an air cylinder (not shown). The center (axis of the hollow portion 11a of the material 11) X3 is positioned on the same line. Further, the first metal core 4 protrudes from the lower end (tip portion) of the first sleeve punch 3 by a predetermined amount.

  Next, as shown in FIGS. 1 and 2A, the material 11 is inserted into the large diameter portion 12 and arranged. The outer diameter of the material 11 is set to be substantially the same as or slightly smaller than the inner diameter of the large diameter portion 12. The material 11 is made of metal, and any material can be used as long as the hollow portion 11a into which the core bars 4 and 6 can be inserted in the axial direction is formed and both ends thereof are open. For example, a cylinder cut into a predetermined length can be used.

  Next, the upper base 2A is lowered, and as shown in FIG. 2B, the first sleeve punch 3 and the first metal core 4 are integrally moved to the die 7 side (lower side). Before the 1-sleeve punch 3 comes into contact with the material 11, the first metal core 4 is inserted into the hollow portion 11a. Thereafter, the lower end surface of the first sleeve punch 3 is brought into contact with the upper end surface of the material 11. The outer diameter of the first cored bar 4 is set smaller than the inner diameter of the small-diameter part 14 of the die 7, and the outer peripheral surface of the first cored bar 4, the reduced-diameter part 13 and the small-diameter part 14 of the die 7 A molding space is formed between the peripheral surfaces.

  Next, the upper base 2A is further lowered to a predetermined position, and as shown in FIG. 2C, the first sleeve punch 3 and the first metal core 4 are integrally lowered to the predetermined position. The intermediate product 21 is manufactured by performing forward extrusion processing. At this time, as shown in FIG. 2C, the tip of the cored bar 4 protrudes from the lower end of the intermediate product 21.

  Next, the first core metal 4 is moved relative to the first sleeve punch 3, that is, the first sleeve punch 3 is left in the die 7 as it is, and only the first core metal 4 is moved. The first cored bar 4 is extracted from at least the hollow portion 21a of the intermediate product 21 by moving upward.

  Next, the upper base 2A is moved upward to raise the first sleeve punch 3 and the first cored bar 4 to predetermined positions as shown in FIG. 2 (d). The intermediate product 21 remains inserted into the large diameter portion 12 of the die 7 or the like. Thus, by extracting only the first cored bar 4 from the hollow portion 21 a first, the intermediate product 21 reliably remains in the large-diameter portion 12 of the die 7.

(Second step)
Next, the first sleeve punch 3 and the first cored bar 4, and the second sleeve punch 5 and the second cored bar 6 are moved to the right in FIG. ), The axis X2 of the second sleeve punch 5 and the second core 6 is the same as the axis X3 of the large diameter portion 12 of the die 7 (the axis of the hollow portion 21a of the intermediate product 21). Thus, the first sleeve punch 3 and the first metal core 4 are replaced with a second sleeve punch 5 and a second metal core 6. Further, the second cored bar 6 is protruded by a predetermined amount from the lower end of the second sleeve punch 5, and the protruding amount is the first cored bar 4 in the state of FIG. 2A as shown in FIG. Is set smaller than the amount of protrusion.

  Next, the upper base 2A is lowered, and as shown in FIG. 3B, the second sleeve punch 5 and the second cored bar 6 are integrally moved to the die 7 side (lower side). Before the two-sleeve punch 5 comes into contact with the intermediate product 21, the second cored bar 6 is inserted into the hollow portion 21a. Thereafter, the lower end surface of the second sleeve punch 5 is brought into contact with the upper end surface of the intermediate product 21.

  Next, the upper base 2A is further lowered to a predetermined position, and as shown in FIG. 3C, the second sleeve punch 5 and the second cored bar 6 are integrally lowered to the predetermined position. . At this time, the lower end surface of the second sleeve punch 5 is moved to a position below the lower end surface of the first sleeve punch 3 in FIG. A hollow product 25 having a step on the outer peripheral surface is produced by performing a forward extrusion process deeper than the state of FIG. At this time, the lower end of the second cored bar 6 does not protrude from the lower end of the hollow article 25 as shown in FIG. Moreover, it is preferable that the lower end of the 2nd metal core 6 is located below the reduced diameter part 13 as shown in FIG.3 (c).

  Next, only the second metal core 6 is moved upward to extract the second metal core 6 from the hollow portion 25a of the hollow article 25, and then the upper base 2A as shown in FIG. Is raised to a predetermined position.

  Next, the knockout pin 28 shown in FIG. 1 is moved upward from below the small diameter portion 14 of the die 7 to discharge the hollow product 25 from the die 7.

  As described above, when the hollow product 25 having a large L / D is manufactured (forged) by gradually reducing the protruding amount of the core metal and manufacturing (forging) the hollow product 25 by a plurality of processes. Since the mandrel can be made shorter than the conventional manufacturing method, the frictional force between the mandrel and the material can be reduced, and the life of the mandrel can be extended.

  In Example 1, the hollow article 25 was produced from the material 11 by two forward extrusion processes. However, the hollow article 25 has a plurality of forward extrusion processes, and the core from the lower end surface of the sleeve punch during the forward extrusion process. The amount of protrusion of the gold may be gradually reduced for each processing, and the number of forward extrusion processes and the amount of protrusion of the cored bar from the lower end surface (tip portion) of the sleeve punch at that time are as follows. It is arbitrarily set according to the relationship of / D and the material 11.

  Further, as a method of replacing the first sleeve punch 3 and the first cored bar 4 with the second sleeve punch 5 and the second cored bar 6, any method such as a rotary table type as well as the slide type as described above is used. be able to.

[Example 2]
FIG. 4 shows a second embodiment of the present invention.

  In the first embodiment, the plurality of metal cores 4 and 6 are used. In the second embodiment, the same metal core is used, and the sleeve punch is added step by step for each processing, thereby performing forward extrusion processing. The number of protrusions of the metal core from the sleeve punch tip is gradually shortened as the number of times elapses.

The manufacturing method of the hollow goods of Example 2 of this invention is demonstrated.
First, the intermediate | middle goods 21 are manufactured by performing the 1st process similar to FIG. 2 (a)-(d) in the said Example 1. FIG.

  Next, as shown in FIG. 4 (a), a second sleeve punch 31 is inserted below the first sleeve punch 3 from the tip end side of the core metal 4, and the first mounting is performed by an appropriate attachment method (not shown). Removably attach and add to the sleeve punch 3. The second sleeve punch 31 is formed with a hollow portion 31a having both ends opened in the direction of the axis X1, and the cored bar 4 can slide in the hollow portion 31a.

  By adding the second sleeve punch 31 below the first sleeve punch 3, the maximum protrusion amount of the core metal 4 from the lower end surface of the second sleeve punch 31 is attached only to the first sleeve punch 3. It becomes shorter than the maximum protrusion amount of the metal core 4 in the case.

  Any method can be used for adding the second sleeve punch 31. For example, the second sleeve punch 31 may be conveyed by an industrial robot and fixed to the first sleeve punch 3 by a plunger or the like. It may be done manually.

  Next, the upper base 2A is lowered, and as shown in FIGS. 4B and 4C, both the sleeve punches 3, 31 and the cored bar 4 are integrally moved downward, so that Similarly to the second step, forward extrusion processing is performed deeper than in the first step, and a hollow product 25 having a stepped outer peripheral surface is produced.

Other structures and manufacturing methods are the same as those in the first embodiment.
Also in the second embodiment, the same operations and effects as the first embodiment can be achieved.

  Furthermore, since the same sleeve punch and cored bar as in the first step can be used in the second step, the manufacturing apparatus can be manufactured at a lower cost than in the first embodiment. Moreover, the protrusion amount of the metal core for each front extrusion process can be easily changed.

[Example 3]
FIG. 5 shows a third embodiment of the present invention.

  In the second embodiment, by attaching the second sleeve punch 31 below the first sleeve punch 3, the maximum protrusion amount of the metal core 4 from the lower end surface of the second sleeve punch 31 is set to the first sleeve punch 31. As shown in FIG. 5 (a), the second sleeve punch 31 is placed above the intermediate product 21, as shown in FIG. 5 (a). In this state, as shown in FIGS. 5B and 5C, the first sleeve punch 3 and the cored bar 4 are lowered integrally to form the first step as in the second step of the first embodiment. The hollow article 25 may be manufactured by performing a forward extrusion process deeper than the first step.

  After forging the hollow article 25, when the knockout pin 28 is raised and the hollow article 25 is discharged from the die 7, the second sleeve punch 31 is first taken out by an industrial robot or the like, and then the hollow article 25 is taken out. Like that.

The structure and manufacturing method of the third embodiment are the same as those of the second embodiment except that the installation position of the second sleeve punch 31 is different from that of the second embodiment.
Also in the third embodiment, the same operations and effects as the first and second embodiments can be achieved.

[Example 4]
FIG. 6 shows a fourth embodiment of the present invention.

  In the second step of the first to third embodiments, when the sleeve punches 3 and 5 and the cored bars 4 and 6 are lowered in the second embodiment, as shown in FIG. The other metal core 41 is moved upward and inserted into the hollow portion 21a of the intermediate product 21.

  The outer diameter of the other metal core 41 is set to be the same as or slightly shorter than the inner diameter of the hollow portion 21a. When another cored bar 41 is inserted into the hollow portion 21a, it does not come into contact with the cored bars 4 and 6, as shown in FIG. 6 (c).

  In the second step, the other core metal 41 may be moved upward by a predetermined amount before the sleeve punches 3 and 5 and the core bars 4 and 6 are lowered as shown in FIG. The sleeve punches 3 and 5 and the metal cores 4 and 6 may be moved downward and simultaneously moved upward by a predetermined amount.

  After performing the forward extrusion process, as shown in FIG. 6D, the sleeve punches 3 and 5 and the core bars 4 and 6 are raised, and the other core bars 41 are moved downward to After pulling out from the hollow portion 25a, the hollow article 25 is taken out from the die 7 by any take-out means.

  In this embodiment, the hollow article 25 is manufactured by two forward extrusion processes, and the other cored bar 41 is inserted into the hollow portion during the second forward extrusion process. When the hollow article 25 is manufactured by the extrusion process, the other core metal 41 may be inserted into the hollow part at least once in the second and subsequent processes.

Other structures and manufacturing methods are the same as those in the first to third embodiments.
Also in the fourth embodiment, the same operations and effects as the first to third embodiments can be achieved.

  Further, by inserting the cored bars 4 (6) and 41 into the hollow portion 21a from above and below, the inner diameter accuracy of the hollow portion 25a of the hollow article 25 and the coaxiality of the inner and outer diameters can be obtained. 1 to 3 can be further increased.

3, 5, 31 Sleeve punch 4, 6 Core metal 7 Die 11 Material 25 Hollow product 41 Other metal core

Claims (2)

Using a sleeve punch and a metal core and a die inserted into the sleeve punch, a material having a hollow portion that opens at both ends is extruded forward to form an outer peripheral surface in a stepped shape. Both ends are opened. In the method for producing a hollow product having a hollow portion,
By providing a plurality of the sleeve punches and adding the sleeve punches in stages, the amount of protrusion of the core bar protruding from the tip of the sleeve punch at the time of forward extrusion is reduced in stages while being reduced in stages. A method for producing a hollow product, comprising performing a forward extrusion process to produce a hollow product in stages. At least one of the sleeve punch and the metal core is reciprocated a plurality of times, and another metal core is inserted into the hollow portion from the opening on the material opposite to the metal core. The method for producing a hollow article according to claim 1 .

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