JP5771231B2 - Forging method and apparatus - Google Patents

Description

  The present invention relates to a forging method and apparatus for subjecting a workpiece to at least backward extrusion.

  In various automobiles including four-wheel automobiles and two-wheel automobiles, a drive motor may be used as a travel drive source. That is, a hybrid vehicle on which both an internal combustion engine and a drive motor are mounted, an electric vehicle (or a fuel cell electric vehicle) on which only a drive motor is mounted, and the like.

  In this type of automobile, the rotational driving force of the driving motor is transmitted to driving wheels (tires) via a drive shaft connected to the driving motor by a constant velocity joint. As a result, the driving wheel rotates, and the vehicle travels.

  As is well known, the constant velocity joint includes an outer member having a cup portion in which a bottomed hole is formed, and an inner member that is inserted into the bottomed hole and fitted to the tip of the drive shaft. For example, in the sliding type constant velocity joint constituting the power unit for an electric vehicle described in Patent Document 1, a plurality of grooves are formed along the longitudinal direction in the inner wall of the bottomed hole, and the groove is formed in the inner member. Protrusions that are inserted into each of these are provided. When the protrusion slides in the groove, the tip of the drive shaft can be advanced toward the bottom of the bottomed hole, or conversely, can be retracted toward the opening of the bottomed hole.

  Recently, attempts have been made to reduce the number of parts in order to simplify the configuration of the power unit for an electric vehicle having such a configuration. Therefore, for example, it is conceivable to form a tooth portion on the outer member (cup portion) of the constant velocity joint and to mesh this tooth portion with, for example, the first tooth portion of a two-stage helical gear. In this case, if the second tooth portion of the two-stage helical gear is engaged with a gear member that rotates under the action of the driving motor, the outer member of the constant velocity joint can also be used as a member constituting the speed reduction mechanism. can do.

  It is difficult to engrave such a tooth part directly on the outer wall of the cup part. For this reason, it is recalled that the outer peripheral wall of the cup portion protrudes radially outward and is engraved on the side peripheral wall of the large-diameter portion that is larger in diameter than other portions.

  However, it is not easy to obtain an outer member integrally having a cup portion and a large-diameter portion protruding from the outer wall of the cup portion by forging. This point will be briefly described.

  7A to 7C, the cylindrical body 4 is pressed by the double punch 3 having the first punch part 1 and the cylindrical second punch part 2 surrounding the first punch part 1, It is a schematic flow of the process of shape | molding both the cup part 5 and the large diameter part 6 (both refer FIG. 7C). Here, each of the first punch part 1 and the second punch part 2 is one part of the double punch 3, and therefore, the first punch part 1 and the second punch part 2 are lowered or raised integrally. To do. Note that the lower end surface of the second punch portion 2 is set to be higher than the lower end surface of the first punch portion 1.

  In this case, when the double punch 3 descends toward the cylindrical body 4, first, the lower end surface of the first punch portion 1 comes into contact with the upper end surface of the cylindrical body 4 as shown in FIG. 7A.

  Thereafter, when the double punch 3 is further lowered, as shown in FIG. 7B, the cylindrical body 4 is pressed by the first punch portion 1, and the meat in the vicinity of the outer edge rises. The vicinity of the outer edge of the raised meat is blocked by the second punch portion 2, and the remaining meat enters the clearance 7 between the first punch portion 1 and the second punch portion 2 as shown in FIG. To rise. Thereby, it is thought that the cup part 5 and the large diameter part 6 are shape | molded.

  However, in this case, the meat hardly flows to the end of the cavity 8. In other words, there is a problem in that an unfilled portion is likely to occur as indicated by x in FIG. That is, it is difficult to obtain a molded body with a high yield.

  In addition, the stress of the meat that tends to rise against the pressing from the second punch portion 2 acts on the lower end surface of the second punch portion 2, and the inner peripheral wall of the meat that flows through the clearance 7 Stress acts. In order to provide sufficient durability against such a large stress, for example, it is necessary to increase the rigidity of the second punch portion 2 with a large thickness.

  Therefore, as proposed in Patent Document 2, it is considered effective to produce the outer member and the large-diameter portion as separate members and then connect the two members.

Japanese Patent No. 4379867 JP 2007-10029 A

  The constant velocity joint needs to rotate at a high speed and has a heavy load. For this reason, as described in Patent Document 2, a tooth portion is engraved on the side peripheral wall of the large-diameter portion manufactured as a separate member from the cup portion, and another member (such as a two-stage helical gear) is provided on the tooth portion. When meshing the teeth and rotating the large diameter portion, the connection between the large diameter portion and the cup portion is released, and as a result, there is a concern that the large diameter portion may idle. In addition, since it is necessary to separately provide a forging device for producing the cup portion and a forging device for producing the large-diameter portion, there is also a problem that capital investment increases.

  The present invention has been made to solve the above-described problem, and a forging method and a method for easily obtaining a molded body integrally having a cup portion and a large-diameter portion protruding from the outer wall of the cup portion, and An object is to provide such a device.

In order to achieve the above object, the present invention provides a hollow cup portion provided from the cylindrical portion, from a workpiece having a cylindrical portion and a flange portion protruding in a radial direction from a side peripheral wall of the cylindrical portion, A forging method for obtaining a molded body provided from a flange portion and having a large diameter portion larger than the cup portion,
Contacting the cylindrical portion of the ring punch against the flange portion of the workpiece supported by a die;
Pressing the cylindrical part of the workpiece with a punch to perform backward extrusion, and molding the cup part from the cylindrical part;
Have
The flange of the cylindrical portion of the ring punch while the meat of the flange portion flows in the direction opposite to the pressing direction by the punch as the thickness of the cylindrical portion flows in the direction opposite to the pressing direction by the punch. The cylindrical portion is displaced in a direction in which the flesh of the flange portion flows while maintaining contact with the portion.

Further, the present invention provides a hollow cup portion provided from the columnar portion and a flange portion provided from the workpiece including a columnar portion and a flange portion protruding in a radial direction from a side peripheral wall of the columnar portion, and the flange portion. A forging device for obtaining a molded body having a large-diameter portion that is larger than the cup portion,
A die formed with a cavity for supporting the workpiece;
A punch for forming the cup part from the cylindrical part by pressing the cylindrical part of the work supported by the die and performing a backward extrusion process;
An elevating mechanism for displacing the punch in a direction approaching or separating from the workpiece;
A ring punch that has a cylindrical portion that surrounds the punch from the outside, and the tip surface of the cylindrical portion abuts on the flange portion of the workpiece while the punch presses the column portion of the workpiece;
A second lifting mechanism for displacing the ring punch in a direction approaching or separating from the workpiece separately from the punch;
Have
The ring punch, while the flesh of the cylindrical portion meat of the flange with that flow in the pressing direction opposite to the direction by the punch flows in the pressing direction opposite to the direction by the punch, meat of the flange The cylindrical portion is kept in contact with the flange portion while being displaced in a flowing direction .

  In other words, the ring punch can be displaced independently of the punch, and during the backward extrusion process (forging process), the ring punch is displaced in the direction of flesh flow while maintaining contact with the flange part. To do. By operating the ring punch in this way, it is possible to avoid the formation of an unfilled portion in the cavity. As a result, it is possible to easily obtain a molded body integrally having a cup portion and a large diameter portion.

  Therefore, it is not necessary to separately provide a forging device for producing the cup portion and a forging device for producing the large diameter portion. For this reason, capital investment does not soar.

  Moreover, since the cup part and the large diameter part are provided as separate parts in the same member (integrally provided) in the obtained molded body, for example, a tooth part is formed on the side peripheral wall of the large diameter part. However, even in the case where the gear is configured by meshing with the tooth portions of other members, the concern that the large-diameter portion idles is eliminated.

  During the backward extrusion process, the flesh of the cylindrical part of the workpiece flows into the clearance between the punch and the ring punch. Therefore, the stress from the flowing meat acts on the ring punch.

  Therefore, the ring punch is preferably constituted by a plurality of divided pieces, in other words, a divided body. In this case, since the rigidity of the ring punch is reduced, when stress is applied from the flowing meat, the divided pieces are slightly opened or the divided pieces are bent in the elastic deformation region. Thereby, stress is absorbed (relaxed).

  Therefore, it is not necessary to make the ring punch, die, etc. thick enough to withstand stress. For this reason, it can avoid that a forge processing apparatus enlarges and weights.

  It is preferable that the divided pieces have the same shape. In this case, the stress can be relieved substantially uniformly. For this purpose, the cylindrical portion of the ring punch may be divided along the diameter direction and the longitudinal direction.

  In addition, while the cylindrical portion of the ring punch maintains contact with the flange portion when the flange portion flows in the direction opposite to the pressing direction by the punch, the second lifting mechanism moves the ring punch to the flange portion side. It is preferable to apply a force that advances to. In this case, since the flesh of the flowing flange part is pressed to some extent by the ring punch, it is possible to suppress the flare of the flange part from flowing excessively. Therefore, it is possible to obtain a large-diameter portion with good dimensional accuracy.

  You may make it form the recessed part for forming the axial part which protrudes from the one end surface of the said large diameter part and extends in a reverse direction to the said cup part in a cavity. In this case, the forward extrusion process is performed during the backward extrusion process, and the cup part, the large diameter part, and the shaft part can be formed in one step.

  According to the present invention, a ring punch that is displaceable independently of the punch is provided, and the ring is formed on the flange portion that flows in the direction opposite to the pressing direction by the punch during the backward extrusion process on the workpiece. The state in which the punch is in contact is maintained. As a result, the formation of an unfilled portion in the cavity is avoided, and as a result, a molded body integrally having a cup portion and a large diameter portion can be easily obtained.

  For this reason, since it is not necessary to provide the forge processing apparatus which produces a cup part, and the forge processing apparatus which produces a large diameter part separately, it can avoid that capital investment soars.

  In addition, since a molded body integrally having the cup portion and the large diameter portion is obtained, there is no concern that the large diameter portion idles when a gear is formed from the large diameter portion of the molded body.

FIG. 1A to FIG. 1D are schematic flows showing in cross-section the process from obtaining a molded body from a billet. It is a schematic front longitudinal cross-sectional view of the forge processing apparatus which concerns on embodiment of this invention. It is a top view of the division piece which comprises the ring punch contained in the said forge processing apparatus. FIG. 4A to FIG. 4D are schematic flows showing a cross section of a process until a molded body is obtained from a workpiece in the forging apparatus. In the forging device, it is a schematic front longitudinal sectional view showing a state where a punch has reached a bottom dead center and a formed body is formed. FIG. 6A and FIG. 6B are schematic flows showing in cross section the process of raising the punch and the ring punch after the molded body is formed. FIG. 7A to FIG. 7C are schematic flows showing a cross section of a process until a molded body is obtained from a cylindrical body by a double punch.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a forging method according to the present invention will be described in detail with reference to the accompanying drawings by giving preferred embodiments in relation to a forging device that performs the forging method. In the present embodiment, a case where an intermediate body for obtaining an outer member of a constant velocity joint is manufactured as a molded body is illustrated.

  First, a workpiece subjected to forging by the forging device according to the present embodiment and a molded body obtained from the workpiece will be described with reference to FIGS. 1A to 1D.

  The workpiece is obtained using a substantially cylindrical billet 10 shown in FIG. 1A as a starting material. Since the final product is an outer member of a constant velocity joint, the billet 10 is preferably made of a mechanical structural alloy steel such as SCR or SCM.

  The billet 10 made of such a material is subjected to preheating, lubricant application, main heating, etc., and then upsetting (generally warm forging). As a result, as shown in FIG. 1B, a first portion having a cylindrical portion 12 and a flange portion 14 provided at one end portion (the upper end portion in FIG. 1B) of the cylindrical portion 12 and having a larger diameter than the cylindrical portion 12. A workpiece 16 as a next intermediate is formed.

  Next, the workpiece 16 is accommodated in the cavity 32 of the forging device 30 (see FIG. 2) in a state where the workpiece 16 is turned upside down as shown in FIG. 1C, and backward extrusion is performed. That is, the bottomed hole 18 is formed in the cylindrical part 12 while flowing the meat of the cylindrical part 12 in the direction opposite to the pressing direction. At this time, the flesh of the flange portion 14 also flows in the direction opposite to the pressing direction. As a result, as shown in FIG. 1D, a molded body 24 as a secondary intermediate body having a cup portion 20 provided from the cylindrical portion 12 and a large diameter portion 22 provided from the flange portion 14 is obtained. It reaches.

  The molded body 24 further has a small-diameter shaft portion 26 that protrudes from the large-diameter portion 22 and is directed in the direction opposite to the cup portion 20. As will be described later, the shaft portion 26 is formed simultaneously with the forging process for forming the cup portion 20 and the large diameter portion 22.

  The forging device 30 according to the present embodiment is for performing the above-described backward extrusion processing on the workpiece 16 (see FIGS. 1B and 1C) to obtain a molded body 24 (see FIG. 1D). Hereinafter, the forging device 30 will be described in detail.

  FIG. 2 is a schematic front longitudinal sectional view of the forging device 30 according to the present embodiment. The forging device 30 includes a fixed platen 38 including a lower die 34 and an upper die 36, and a movable platen 44 including a punch 40 and a ring punch 42 that are displaced toward or away from the fixed platen 38. Have.

  The fixed platen 38 is positioned and fixed to an installation table (not shown) provided in the work station. A first press-fitting hole 46 is formed in the fixed platen 38, and an inner base 48 and an outer base 50 having a substantially disk shape are press-fitted into the first press-fitting hole 46 from the inner side in this order. Of course, the inner base 48 is press-fitted into a second press-fitting hole 51 formed through the outer base 50.

  A base 52 is positioned and fixed on the inner base 48 and the outer base 50 so as to straddle the inner base 48 and the outer base 50. Further, a lower die 34 is disposed on the pedestal 52, and a lower die holder 54 that is externally fitted to the lower die 34 is placed thereon. The lower die 34 is fitted in a fitting hole 56 formed in the lower die holder 54.

  The inner base 48 and the lower die 34 are formed with sliding holes 58 extending toward the movable platen 44. A knockout pin 60 slides in the sliding hole 58.

  In the vicinity of the outer edge of the lower die 34 and the vicinity of the fitting hole 56 of the lower die holder 54, a processing hole 62 is formed, and the upper die 36 having a substantially cylindrical shape is disposed. A cavity 32 is formed by the upper end surface of the knockout pin 60, the circular step portion 64 (see FIG. 4A) that is recessed in a substantially circular shape on the upper end surface of the lower die 34, and the inner peripheral wall of the processing hole 62 of the upper die 36. Is formed.

  The upper end surface of the knockout pin 60 is positioned slightly below the circular step portion 64 (see FIG. 2). Therefore, the cavity 32 includes a recess 66 formed by the upper end surface of the knockout pin 60 and the inner peripheral wall near the upper end of the sliding hole 58 of the lower die 34.

  The inner diameter of the processing hole 62 substantially matches the diameter of the flange portion 14 of the workpiece 16. On the other hand, the diameter of the circular step portion 64 is slightly smaller than that of the flange portion 14. Therefore, when the workpiece 16 is accommodated in the cavity 32, the side peripheral wall of the flange portion 14 abuts against the inner peripheral wall of the processing hole 62, while the end surface (lower end surface) facing the lower die 34 of the flange portion 14 is , At a position slightly separated from the circular step 64 (see FIG. 4A).

  An upper die holder 67 is fitted on the upper die 36, and a lower sleeve 68 installed on the upper end surface of the fixed plate 38 is fitted on the base 52, the lower die holder 54, and the upper die holder 67 (FIG. 2). reference). In other words, the pedestal 52, the lower die 34, the lower die holder 54, the upper die 36, and the upper die holder 67 are accommodated in the lower sleeve 68.

  The lower sleeve 68 has a ceiling wall and a side peripheral wall, and a die-side cap 72 having a first insertion hole 70 formed through the ceiling wall is fitted therein. When the outer peripheral wall of the lower sleeve 68 is pressed radially inward by the side peripheral wall of the die side cap 72, the pedestal 52, the lower die holder 54, and the upper die holder 67 are pressed inward in the radial direction. Thus, each positioning is fixed.

  One movable platen 44 is connected to a rod of a hydraulic cylinder (first lifting mechanism) (not shown). The movable platen 44 is displaced so as to approach the fixed platen 38 as the rod advances (lowers) toward the fixed platen 38 side. On the contrary, when the rod is retracted (raised) so as to be separated from the fixed platen 38, it is displaced so as to be separated from the fixed platen 38.

  The movable platen 44 is formed with a third press-fit hole 74 therethrough. A punch holder 76 is press-fitted into the third press-fitting hole 74. Further, in the punch holder 76, the punch 40 is provided at an end portion (lower end portion) facing the fixed platen 38. As understood from FIG. 2, the punch 40 and the ring punch 42 enter the cavity 32 through the first insertion hole 70 of the die-side cap 72.

  In the punch 40, when the cup part 20 is formed from the cylindrical part 12, a plurality of (for example, three) grooves (not shown) are formed on the inner wall of the cup part 20 along the longitudinal direction. Land is provided.

  An upper sleeve 78 installed on the lower end surface of the movable platen 44 is fitted on the punch holder 76. By fitting the punch side cap 82 with the second insertion hole 80 penetratingly formed in the bottom wall into the upper sleeve 78, the punch holder 76 is pressed inward in the radial direction. That is, the punch holder 76 is positioned and fixed. The punch 40 is exposed from the punch-side cap 82 through the second insertion hole 80.

  An accommodation chamber 86 for arranging a plurality of hydraulic cylinders 84 serving as a second lifting mechanism is formed at the upper end of the punch holder 76. Here, the hydraulic cylinder 84 is supported by a support plate (not shown), and a plurality of rod holes 88 extending from the bottom wall of the storage chamber 86 toward the fixed plate 38 are formed in the punch holder 76 so as to penetrate therethrough. Yes. Each rod 90 of the hydraulic cylinder 84 is passed through each rod hole 88.

  The lower end of the rod 90 is exposed from the rod hole 88. The ring punch 42 is attached to the tip of the lower end of the rod 90 exposed from the rod hole 88.

  The ring punch 42 includes a cylindrical portion 92 having a substantially cylindrical shape, and an attachment portion 94 provided at the upper end portion of the cylindrical portion 92. The cylindrical portion 92 in this surrounds the punch 40. On the other hand, the mounting portion 94 having a diameter larger than that of the cylindrical portion 92 is formed with a plurality of mounting holes 96 as shown in FIG. 3, and the tip of the lower end of the rod 90 is fitted into the mounting hole 96. Is done.

  As shown in FIG. 3, the ring punch 42 is a divided body including a first divided piece 98 and a second divided piece 100. That is, the 1st division piece 98 and the 2nd division piece 100 make the shape formed by dividing into 2 along the diameter direction of the attachment part 94 and the cylindrical part 92, and the longitudinal direction. Accordingly, each of the first divided piece 98 and the second divided piece 100 includes semi-cylindrical portions 92a and 92b each having a shape obtained by cutting the cylindrical portion 92 into two pieces in the longitudinal direction, and two attachment portions 94 along the diameter direction. There are semi-disc shaped portions 94a and 94b having a divided shape.

  The first divided piece 98 and the second divided piece 100 are in contact with each other but are not connected. Accordingly, the rigidity of the first divided piece 98 and the second divided piece 100 is relatively small. When the ring punch 42 is pressed from the inside, the gap between the first divided piece 98 and the second divided piece 98 is slightly opened or the first divided piece 98 is. Or the second divided piece 100 can be bent in the elastic deformation region.

  The forging device 30 according to the present embodiment is basically configured as described above. Next, the operation and effect thereof will be described in relation to the forging method according to the present embodiment. .

  In order to perform the backward extrusion processing on the workpiece 16, first, the forging device 30 is brought into the mold open state. Then, the workpiece 16 (see FIGS. 1B and 1C) obtained as described above is processed so that the flange portion 14 faces downward and the cylindrical portion 12 faces upward, as shown in FIGS. 1C, 2 and 4A. It is inserted into the use hole 62 and accommodated in the cavity 32. As can be seen from FIG. 4A, at this time, the side peripheral wall of the flange portion 14 abuts against the inner peripheral wall of the processing hole 62, while the lower end surface of the flange portion 14 is slightly separated from the circular step portion 64. .

  Next, the hydraulic cylinder 84 is energized, and each rod 90 is moved forward (down) toward the fixed platen 38 side. Along with this, the ring punch 42 (the first divided piece 98 and the second divided piece 100) descends and enters the processing hole 62 (cavity 32). Finally, the lower end surface of the cylindrical portion 92 of the ring punch 42 is seated on the upper end surface of the flange portion 14 of the workpiece 16.

  Simultaneously with this seating, the cylindrical portion 12 of the workpiece 16 is inserted into the ring punch 42. In other words, the ring punch 42 surrounds the cylindrical portion 12 with its inner peripheral wall.

  The hydraulic cylinder 84 is not de-energized after the above seating. Accordingly, a pressing force is applied to the flange portion 14 via the rod 90. However, the pressing force is not so large that the flange portion 14 can be plastically deformed, and is an extent that the flesh of the flange portion 14 can be prevented from excessively rising during the backward extrusion process with respect to the cylindrical portion 12.

  In this state, next, the hydraulic cylinder (not shown) is energized, and the rod is advanced (lowered) toward the fixed platen 38 side. As a result, the movable platen 44 descends, and eventually the punch 40 descends. The punch 40 passes through the first insertion hole 70 of the die-side cap 72 and enters the processing hole 62 (cavity 32). 2 and 4A are cross-sectional views in which the lower end surface of the ring punch 42 is seated on the upper end surface of the flange portion 14 and the lower end surface of the punch 40 that has entered the cavity 32 is in contact with the upper end surface of the cylindrical portion 12. It shows.

  A predetermined clearance 102 is formed between the side peripheral wall of the punch 40 and the inner peripheral wall of the ring punch 42. That is, the lower end surface of the punch 40 does not contact the vicinity of the outer edge of the cylindrical portion 12.

  When the movable platen 44 is further lowered, the cylindrical portion 12 is pressed by the punch 40 (that is, the direction of the pressing force by the punch 40 is vertically downward). Here, since a clearance 102 is formed between the side peripheral wall of the punch 40 and the inner peripheral wall of the ring punch 42, as shown in FIG. It flows to rise along. Thus, the backward extrusion is performed by the meat of the cylindrical portion 12 flowing in the direction opposite to the pressing force applied by the punch 40.

  On the other hand, on the lower end surface of the cylindrical portion 12, most of the meat flows into the circular step portion 64 and a part of the meat flows into the recess 66 (upper end surface side of the knockout pin 60). That is, forward extrusion is performed, and the shaft portion 26 having a shape corresponding to the shape of the recess 66 is formed.

  As shown in FIG. 4C, when the punch 40 is further lowered, the meat of the cylindrical portion 12 is further raised. Thereby, the cup part 20 in which the bottomed hole 18 is formed is molded. Since the land is provided in the punch 40, a groove is formed on the inner wall of the cup 20 (bottomed hole 18) at the same time as the cup 20 is molded.

  Most of the meat of the cylindrical portion 12 rises as described above, but a part flows toward the flange portion 14. The flesh of the flange portion 14 is pushed out by this surplus flesh and eventually rises against the pressure from the ring punch 42. That is, the flange portion 14 also flows in a direction opposite to the direction of the pressing force by the punch 40, thereby forming the large diameter portion 22 (see FIG. 1D).

  The ring punch 42 is subjected to a forward drive force by the hydraulic cylinder 84, that is, a force traveling toward the flange portion 14 side. Accordingly, the ring punch 42 presses the flange portion 14 with a predetermined pressing force while maintaining contact with the flange portion 14 while being raised (retracted). For this reason, it is avoided that the thickness of the cylindrical part 12 flows excessively to the flange part 14 side, and that the meat of the flange part 14 rises exceeding a predetermined amount. Therefore, the dimensional accuracy in the height direction of the cup part 20 and the large diameter part 22 is improved.

  When the punch 40 reaches the bottom dead center as shown in FIG. 4D and FIG. 5, the flow of the meat of the cylindrical portion 12 (cup portion 20) and the flange portion 14 (large diameter portion 22) stops accordingly, The extrusion process ends. That is, the molded body 24 is obtained.

  In the present embodiment, the molded body 24 integrally having the cup portion 20 and the large diameter portion 22 is produced by a single backward extrusion process. For this reason, this molded object 24 can be obtained efficiently. Moreover, since it is not necessary to provide the forging apparatus 30 which produces the cup part 20, and the forging apparatus 30 which produces the large diameter part 22, it can also avoid that a capital investment rises.

  While the cup part 20, the large diameter part 22 and the shaft part 26 are formed as described above, the ring punch 42 receives stress from the meat flowing along the inner peripheral wall of the ring punch 42. In the present embodiment, the ring punch 42 is a divided body composed of the first divided piece 98 and the second divided piece 100, and the first divided piece 98 and the second divided piece 100 are not connected. For this reason, the stress acting from the inside of the ring punch 42 is slightly opened between the first divided piece 98 and the second divided piece 100, or the first divided piece 98 and the second divided piece 100 are elastically deformed. It is alleviated by bending in the area.

  Therefore, it is possible to avoid an excessively large stress acting on the ring punch 42. For this reason, the concern that the ring punch 42 is deformed or damaged is wiped away.

  After the molded body 24 is obtained as described above, the rod of the hydraulic cylinder (not shown) is retracted (raised), and the punch 40 is raised following this as shown in FIG. 6A. As a result, the punch 40 is detached from the cup portion 20.

  Further, when the punch 40 is retracted (raised) by a predetermined amount, the rod 90 of the hydraulic cylinder 84 is retracted. As shown in FIG. 6B, the ring punch 42 is raised and separated from the large diameter portion 22.

  When the movable platen 44 is separated from the fixed platen 38 by a predetermined distance, the mold is opened. During or before and after that, the knockout pin 60 disposed in the sliding hole 58 rises and pushes the molded body 24 out of the cavity 32. Thereby, the molded body 24 is taken out from the cavity 32.

  The molded body 24 obtained as described above is subjected to a spheroidizing annealing process, a shot blasting process, a lubricating film forming process, and the like as necessary. Further, ironing (generally cold forging) is performed on the formed body 24 to finish the outer member of the constant velocity joint.

  And by engraving a tooth part with respect to the side peripheral wall of the large diameter part 22, the outer member as a final product will be obtained.

  When the gear is configured from the tooth portion, when the large diameter portion 22 rotates, the cup portion 20 rotates following the rotation. This is because both the cup part 20 and the large diameter part 22 are one part of the outer member.

  That is, in this case, it is possible to configure an outer member that does not cause the large-diameter portion 22 to idle.

  The present invention is not particularly limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

  For example, the number of divided pieces of the ring punch 42 may be three or more.

  Moreover, although the intermediate body used as the outer member of a constant velocity joint is illustrated as the molded object 24, the molded object 24 is not specifically limited to this, The hollow cup part 20 and this cup part 20 are not limited to this. What is necessary is just to have the large diameter part 22 large diameter compared with.

  Further, the ring punch 42 and the punch 40 may be lowered such that the ring punch 42 is seated on the upper end surface of the flange portion 14 and the punch 40 is seated on the upper end surface of the cylindrical portion 12.

DESCRIPTION OF SYMBOLS 1 ... 1st punch part 2 ... 2nd punch part 3 ... Double punch 4 ... Cylindrical body 5, 20 ... Cup part 6, 22 ... Large diameter part 7, 102 ... Clearance 8, 32 ... Cavity 10 ... Billet 12 ... Cylinder Part 14 ... Flange part 16 ... Work piece 18 ... Bottom hole 24 ... Molded body 26 ... Shaft part 30 ... Forging device 34 ... Lower die 36 ... Upper die 38 ... Fixed plate 40 ... Punch 42 ... Ring punch 44 ... Movable plate 60 ... Knockout pin 62 ... Processing hole 64 ... Circular step part 66 ... Recess 84 ... Hydraulic cylinder 88 ... Rod hole 90 ... Rod 92 ... Cylindrical part 92a, 92b ... Semi-cylindrical part 94 ... Mounting part 94a, 94b ... Semi-disc shape Part 96 ... Mounting hole 98 ... First divided piece 100 ... Second divided piece

Claims (7)

From a workpiece having a cylindrical portion and a flange portion protruding radially from a side peripheral wall of the cylindrical portion, a hollow cup portion provided from the cylindrical portion, and provided from the flange portion, compared to the cup portion A forging method for obtaining a molded body having a large-diameter portion having a large diameter,
Contacting the cylindrical portion of the ring punch against the flange portion of the workpiece supported by a die;
Pressing the cylindrical part of the workpiece with a punch to perform backward extrusion, and molding the cup part from the cylindrical part;
Have
The flange of the cylindrical portion of the ring punch while the meat of the flange portion flows in the direction opposite to the pressing direction by the punch as the thickness of the cylindrical portion flows in the direction opposite to the pressing direction by the punch. A forging method characterized by maintaining contact with the part and displacing the cylindrical part in a direction in which the meat of the flange part flows.   2. The processing method according to claim 1, wherein when the flesh of the flange portion flows in a direction opposite to the pressing direction by the punch, the cylindrical portion of the ring punch maintains contact with the flange portion. A forging method characterized by applying a force to the ring punch toward the flange while the meat is displaced in the flowing direction. From a workpiece having a cylindrical portion and a flange portion protruding radially from a side peripheral wall of the cylindrical portion, a hollow cup portion provided from the cylindrical portion, and provided from the flange portion, compared to the cup portion A forging device for obtaining a molded body having a large diameter and a large diameter portion,
A die formed with a cavity for supporting the workpiece;
A punch for forming the cup part from the cylindrical part by pressing the cylindrical part of the work supported by the die and performing a backward extrusion process;
An elevating mechanism for displacing the punch in a direction approaching or separating from the workpiece;
A ring punch that has a cylindrical portion that surrounds the punch from the outside, and the tip surface of the cylindrical portion abuts on the flange portion of the workpiece while the punch presses the column portion of the workpiece;
A second lifting mechanism for displacing the ring punch in a direction approaching or separating from the workpiece separately from the punch;
Have
The ring punch, while the flesh of the cylindrical portion meat of the flange with that flow in the pressing direction opposite to the direction by the punch flows in the pressing direction opposite to the direction by the punch, meat of the flange A forging device that maintains the contact of the cylindrical portion with the flange portion while being displaced in the direction in which the fluid flows .   The forging apparatus according to claim 3, wherein the ring punch is constituted by a plurality of divided pieces.   The forging apparatus according to claim 4, wherein the cylindrical portion of the ring punch is divided along a diametrical direction and a longitudinal direction.   6. The processing apparatus according to claim 3, wherein the second lifting mechanism is configured such that the cylinder of the ring punch moves when the flange portion flows in a direction opposite to a pressing direction of the punch. A forging apparatus characterized by applying a force to advance the ring punch toward the flange while the portion maintains contact with the flange.   7. The processing apparatus according to claim 3, wherein the cavity is formed with a shaft portion that protrudes from one end surface of the large-diameter portion and extends in a direction opposite to the cup portion. A forging device characterized in that is formed.

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