JP2010082625A - Molding die device and method for molding dieed body having female screw part-fitted shaft hole using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a molding die device having a female screw part-fitted shaft hole, and to provide a method for molding the molding die device. <P>SOLUTION: In the molding die device having the female screw part-fitted screw hole, raw material powder is packed into a die cavity, and the raw material powder is subjected to compression molding by upper/lower punches. The device comprises: a screw part 20a formed at the outer circumference of a core rod 20; rotary driving means (22, 24) rolling the core rod in a state where screw feeding is possible; an upper inner punch 42 and an upper outer punch 40 obtained by dividing the upper punch slidingly contacted with the core rod in the upper punch side; a female screw part 42a formed at the inner circumferential face of the upper inner punch and fitted to the screw part 20a; rotary driving means (44, 45) turned in a state where the upper inner punch is supported; a lower inner punch 34 and a lower outer punch 32 obtained by dividing the lower punch slidingly contacted with the core rod in the lower punch side; a female screw part 34a formed at the inner circumferential face of the lower inner punch and freely slidingly fitted to the screw part 20a; and rotary driving means (35, 36) turned in a state where the lower inner punch is supported. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a powder metallurgy method in which a molded body obtained by compression-molding raw material powder is sintered to produce a machine part, in which molding is performed by filling the raw material powder into a mold cavity of a pressing die and pressing it with a punch. The present invention relates to a mold apparatus and a method for forming a molded body having a shaft hole with a female screw portion using the mold apparatus.

  The powder metallurgy method by the so-called extrusion molding method in which the raw material powder is filled in the die hole provided in the die, the raw material powder is compression-molded by upper and lower punches to give the product shape, and the obtained molded body is sintered is Since it can be shaped into a net shape and suitable for mass production, it is applied to the manufacture of various machine parts.

  In such a powder metallurgy method, there is a configuration disclosed in Patent Document 1 as a method for manufacturing a machine part having a shaft hole with a female screw portion, and FIG. 11 shows a molding die apparatus and method disclosed in Patent Document 1. Yes. This molding die apparatus forms a horizontal hole 2 penetrating from the side of the inner hole of the die 1 and having a female screw portion formed therein, and the male screw 3a is formed in the horizontal hole 2 of the die 1 as an advance / retreat driving capability. The horizontal rod 3 is inserted, and the output portion of the motor 8 mounted on the base 6 so as to be able to advance and retreat by the slider 7 is connected to the horizontal rod 3.

As a molding method using the above molding die apparatus, powder M is filled in a die cavity composed of a die 1, a lower punch 5 and a horizontal rod 3 (FIG. 11A), and the horizontal rod 3 is filled powder. The filled powder M is compression-molded by the upper and lower punches 4 and 5 so as to be in the position of the neutral zone of M (FIG. 11B), and then the upper punch 4 and the lower punch 5 are simultaneously separated from the molded body P. Further, the horizontal rod 3 with the male screw 3a is rotated by the motor 8 to be retracted from the inner hole of the die 1 (FIG. 11 (c)), and then the molded body P is extracted out of the die 1 (FIG. 11 (d)). ).
Japanese Patent Laid-Open No. 04-327398

  In the molding method of Patent Document 1, a molded body P0 having a simple outer shape as shown in FIG. 8 (a) can be molded, but a molded body P1 having a flange portion as shown in FIG. 8 (b) or (c). As for P2, a molded product P3 having a convex portion where the outer peripheral portion of the flange portion becomes higher as in (d), a molded product P4 with a tooth groove having a tooth groove formed on the outer periphery as shown in FIG. Difficult to mold. For this reason, when manufacturing machine parts having shapes such as those shown in FIGS. 8B to 8E by the powder metallurgy method, the machine parts are formed as simple through holes that do not form the female screw portions, and after sintering, The internal thread portion is formed by processing. However, if it can shape | mold in the state which formed the internal thread part in the through-hole, a machining process can be skipped and cost can be reduced by that much. Accordingly, an object of the present invention is to mold a molding device that can be molded even in the shapes of FIGS. 8B to 8E and the like, and a molded body having a shaft hole with a female screw portion using the molding die device. It is to realize a molding method.

In order to achieve the above-mentioned object, the invention according to claim 1 is characterized in that a raw material powder is filled in a die cavity formed by a die hole, a lower punch or a group of lower punches, and a core rod for forming a shaft hole. Alternatively, a molding die device for a molded body having a shaft hole with an internal thread portion that compresses a raw material powder by an upper punch group and the lower punch or lower punch group, the thread portion formed on the upper outer periphery of the core rod And rotating the core rod in a state in which the core rod can be screwed (that is, as in the example of FIG. 1, the core rod has a female screw portion that engages with the screw portion provided on the core rod side, and the core rod can be rotated to be screw-feedable. ) Rotation driving means, upper and lower punches in the upper punch or the upper punch group, the upper and lower punches surrounding the upper punch and the upper and outer punches surrounding the upper punch. A female screw portion formed on the inner peripheral surface of the rod and slidably fitted to a screw portion on the upper outer periphery of the core rod, a rotation driving means that rotates while supporting the upper inner punch, and the lower A lower inner punch formed by dividing a lower punch that is in sliding contact with the core rod and a lower outer punch that surrounds the lower punch among the punches or the lower punch group, and an upper outer peripheral screw formed on the inner peripheral surface of the lower inner punch. It is characterized by comprising a female screw part that is slidably fitted to the part, and a rotation driving means that rotates while supporting the lower inner punch.

  The invention of claim 3 is a method of forming a molded body having a shaft hole with a female thread portion using the molding die apparatus according to claim 1, wherein when the raw powder is filled in the die cavity, The punch surface of the lower inner punch is filled in a state of being arranged below the punch surface of the lower outer punch, and at the time of compression molding, the upper inner punch and the upper and outer punches are lowered together to form each punch. While bringing the punch surface into contact with the raw material powder, rotating the lower inner punch along the core rod side screw portion, raising the relative to the die, aligning with the punch surface of the lower outer punch, The upper inner punch side female thread portion is fitted to the core rod side thread portion, and is further lowered while projecting into the raw material powder in the die cavity while rotating along the core rod side thread portion. And then lowering the upper and outer punches until they are flush with the upper and inner punches, and after the punch surfaces of the upper and outer punches and the upper and inner punches are aligned, Further lowering and rotating the upper inner punch while aligning with the upper and outer punches, and further lowering the lower outer punch relative to the die and simultaneously rotating the lower inner punch It is characterized in that molding is performed by raising the die relative to the lower die in alignment with the lower outer punch.

  The method for forming a molded body having a shaft hole with a female thread portion as described above is characterized in that, when releasing the molded body after the compression molding, the molded body in the die cavity is moved to the upper inner punch and the upper It is preferable that the core rod is extracted from the molded body while being rotated by the rotation driving means after being extracted from the die while being sandwiched between the outer punch, the lower inner punch and the lower outer punch.

  In addition, the molding die apparatus described above is arranged so as to be slidably fitted to the female threaded portion of the upper inner punch as in claim 2 to form a threaded portion continuous with the threaded portion of the core rod. An upper core rod having a female threaded portion that engages with a threaded portion provided on the upper core rod side as in the example of FIG. It is preferable to have rotation driving means that rotates so as to be capable of screw feeding. As the above forming method, it is preferable that the upper core rod described in claim 2 guides rotation and vertical driving of the upper inner punch.

  In the above-described present invention, the “shaft hole” is a hole that is located substantially at the center of the product shape and penetrates in a direction that coincides with the upper and lower punches or the forming shaft. The “shaft hole with a female thread portion” includes a structure in which a part of the shaft hole is formed in the female thread in addition to the shaft hole having a female thread structure. The “thread portion formed on the outer periphery of the core rod” has a thread groove shape formed by transferring the female thread portion. The “lower punch or lower punch group” and the “upper punch or upper punch group” are simply formed with no flange portion as shown in FIG. 8A in the configuration examples of “lower punch” and “upper punch”. Body mold forming apparatus, for example, as shown in FIG. 9 (a), and the configuration examples of the “lower punch group” and the “upper punch group” are molded bodies as shown in FIGS. 8 (b) to 8 (e). For example, it is a form as shown in FIGS. 9 (b) to 9 (d).

  According to the first aspect of the present invention, a molding tool suitable for the molding method according to the third aspect is obtained, and a molded body having a shaft hole with a female thread portion shown in FIGS. It can be formed at the same time as compression molding, thereby reducing the cost by eliminating the machining required conventionally, and as a result, the product range to which the powder metallurgy method is applied can be expanded.

  In the second aspect of the present invention, when the upper core rod and its rotation driving means are provided, the rotation and upper / lower driving of the upper inner punch can be guided and stabilized, and the device reliability can be improved.

  In the present invention of claim 3, for example, as shown in FIGS. 3 and 4, after the raw material powder is pre-compressed by the upper inner punch and the lower inner punch, the upper and outer punches are made flush with the upper inner punch and the punch surface. The raw material powder is caused to flow between the upper inner punch and the lower inner punch including the threaded portion of the core rod, and then the raw material powder is compressed by the final upper inner / outer punch and lower inner / outer punch as shown in FIG. Since it is molded, the density near the threaded part (core rod side threaded part) where the raw material powder is difficult to flow in can be increased, thereby maintaining the uniformity of physical properties and satisfying the quality even with the molded body having the shaft hole with the female threaded part. it can.

  In the present invention of claim 4, when the molded body is extracted, the core rod is rotated by rotating the core rod with the molded body sandwiched between the upper inner punch, the upper outer punch, the lower inner punch, and the lower outer punch as shown in FIG. Can be retracted from the shaft hole with the female thread portion of the molded body.

  According to the fifth aspect of the present invention, since the rotation and vertical driving of the upper inner punch can be guided by the upper core rod of the second aspect, for example, it is possible to reliably prevent the raw material powder from protruding and to stably perform the compression formation. .

  Hereinafter, as a molding die apparatus to which the present invention is applied and a molding method of a molded body having a shaft hole with a female thread portion using the molding apparatus apparatus, the apparatus structure shown in FIGS. 1 to 7 and a molding method using the apparatus structure, FIG. Modifications 1 to 4 shown in FIG. 10 and Modification 5 shown in FIG.

(Apparatus Structure) The molding die apparatus of FIG. 1 has a flange portion on the outer periphery on one end surface side of a shaft hole with a female screw portion and a boss portion forming the shaft hole as shown in FIG. 8B. It is an example of a structure used when the body P1 is compression molded. The apparatus structure is composed of a core rod 20 corresponding to a die hole of the die 10, a lower punch group, and an upper punch group with the die 10 as a reference. In addition, although the drive mechanism of a press is abbreviate | omitted, well-known mechanisms, such as a hydraulic press, are used suitably.

  Here, the die 10 has a mold hole that forms the outer peripheral shape of the molded body, and is used in a state of being fixed to the die plate 11. The mold hole has a hole diameter corresponding to the flange portion of the molded body P1.

  The core rod 20 has a screw portion 20a formed on the outer periphery on the upper end side desired for the die hole of the die 10 and a male screw portion 21a formed on the outer periphery on the lower end side. The threaded portion 20a has a thread groove shape that forms a female threaded portion of the molded body P1. The male screw portion 21 a is formed on the outer periphery of the large-diameter portion 21 by providing a larger-diameter portion 21 on the lower outer periphery of the core rod 20. The core rod 20 described above is rotated via a rotation driving means and is supported so as to move up and down by screw feed accompanying the rotation.

  In other words, the rotational drive means for pivotally supporting the core rod 20 is an example of a worm gear mechanism including a worm wheel 22 and a worm 24. The worm wheel 22 integrally includes a guide tube portion 23 provided at the center, and is supported rotatably on a support base 26 fixed on the base 25 via a bear link mechanism 27 and the like. ing. The guide tube portion 23 has a female screw portion 23a screwed with the male screw portion 21a on the inner periphery. The worm wheel 22 supports the core rod 20 so as to be capable of screw feeding in a state where the male screw portion 21a is screwed with the female screw portion 23a of the guide tube portion 23. The worm 24 meshes with the worm wheel 22 and rotates the worm wheel 22 forward or backward by driving a servo motor (not shown).

  The lower punch group includes a lower first punch 30 having an end surface for forming the flange portion of the molded body P1, a lower second outer punch 32 and a lower second inner punch 34 having end surfaces for forming the boss portion of the molded body P1. It is composed of Of these, the lower first punch 30 is slidably fitted to the die hole of the die 10 and the inner diameter is slidably fitted to the outer diameter of the lower second outer punch 32. The lower first punch 30 is fixedly supported by a lower first punch plate 31 disposed immediately below the die 10.

  The lower second outer punch 32 is slidably fitted with the outer diameter of the lower first punch 30 and the outer diameter is slidably fitted with the outer diameter of the lower second inner punch 34. The lower second outer punch 32 is fixedly supported by the lower second punch plate 33 disposed immediately below the lower first punch plate 31. The lower second inner punch 34 has an outer diameter that is slidably fitted to the inner diameter of the lower second outer punch 32, and has a female screw portion 34a formed on the inner periphery of the end on the punch surface side. The female screw portion 34a is slidably engaged with the core rod side screw portion 20a.

  Further, the lower second inner punch 34 is rotated via a rotation driving means. This rotational drive means is an example of a worm gear mechanism including a worm wheel 35 and a worm 36. More specifically, the worm wheel 35 is rotatably supported with respect to the lower second inner punch plate 38 via a bear link mechanism 37 and the like, and the core rod 20 is attached to the lower second inner punch plate 38 and the worm wheel 35. It is inserted like a skewer from a through hole formed at each center. The lower second inner punch 34 is fixedly supported to the upper surface side of the worm wheel 35. The worm 36 meshes with the worm wheel 35 and rotates the worm wheel 34 and the lower second inner punch 34 in the normal direction or in the reverse direction by driving a servo motor (not shown).

  The structural features of the lower punch group described above are that the lower second punch for forming a boss portion used when forming a molded body in which a conventional shaft hole does not have a female thread portion, and the lower second inner punch 34 and In addition, the core rod 20 is pivotally supported so as to be capable of screw feeding via a rotation drive means (for example, servo motor, worm 23, worm wheel 24). And a female threaded portion 34a corresponding to the threaded portion 20a on the outer periphery of the core rod 20 and slidably fitted to the threaded portion 20a is formed on the inner circumferential surface of the lower second inner punch 34. It is connected to rotation driving means (for example, servo motor, worm 36, worm wheel 34) that enables rotation around the core rod 20 and rotationally drives the lower second inner punch 34.

  On the other hand, the upper punch group is composed of an upper outer punch 40 and an upper inner punch 42 for forming the end surface of the molded body P1 on the flange portion side. The upper and lower punches 40 are driven in the vertical direction by a fluid pressure cylinder 41 a provided in the cylinder-cum-holding member 41. That is, the cylinder / holding member 41 includes a fluid pressure cylinder 41 a provided on the lower side, an arrangement space 41 b provided on the upper side, and the like, and is fixedly supported by the upper punch plate 46.

  The upper inner punch 42 has an outer diameter that is slidably fitted to the inner diameter of the upper and outer punch 40, and has an internal thread portion 42a formed on the inner periphery of the end on the punch surface side, and the internal thread portion 42a is on the core rod side. The screw portion 20a is slidably engaged with the screw portion 20a. Further, the upper inner punch 42 is rotated via a rotation driving means. This rotation driving means is an example of a worm gear mechanism including a worm wheel 43 and a worm 44. That is, the worm wheel 43 is rotatably supported with respect to the arrangement space 41b of the cylinder / holding member 41 via the bear link mechanism 45 or the like. The upper inner punch 42 is fixedly supported on the lower surface side of the worm wheel 43. The worm 44 meshes with the worm wheel 43, and the worm wheel 43 and the lower inner punch 42 are rotated forward or reversely by driving a servo motor (not shown).

(Molding Method) Next, a molding method using the above molding die apparatus will be described with reference to FIGS. FIG. 2 shows the state of filling of the raw material powder. That is, the raw material powder M is filled in a die cavity formed from the die hole of the die 10, the lower first outer punch 30, the lower second outer punch 32, the lower second inner punch 34, and the core rod 20. At this time, it is important that the raw material powder M is filled in a state where the lower second inner punch 34 has its punch surface lowered from the punch surface of the lower second outer punch 32 by h1.

  Next, the upper punch plate 46 is lowered to bring the punch surfaces of the upper and outer punches 40 and 42 into contact with the raw material powder M. From this state, as shown in FIG. 3, the upper punch plate 46 is further lowered, and a servo motor (not shown) is driven to rotate the worm 44 and the worm wheel 43 and the upper inner portion supported by the worm wheel 43. The punch 42 is rotated. By this rotational drive, the upper inner punch 42 has the female screw portion 42a screwed or fitted with the core rod side screw portion 20a, and rotates along the screw portion 20a to project the tip portion into the raw material powder M. At this time, the upper punch plate 46 is lowered, but the position of the upper and outer punches 40 is adjusted via the fluid pressure cylinder 41a so as to maintain the state where the punch surfaces of the upper and outer punches 40 are in contact with the raw material powder. . In this way, only the upper inner punch 42 protrudes into the raw material powder M by h2, and the corresponding portion of the raw material powder M in the vicinity of the punch surface of the upper inner punch 42 is compressed accordingly. Is done.

  Simultaneously with the driving of the upper punch group, on the lower punch group side, a servo motor (not shown) is driven to rotate the worm 36 and the worm wheel 35 and the lower second inner punch supported by the worm wheel 35. While rotating 34, the lower second inner punch 34 is raised relative to the die 10 to align the punch surface of the lower second inner punch 34 with the punch surface of the lower second outer punch 32. At this time, on the lower punch group side, the corresponding portion of the raw material powder M is pre-compressed by a level difference h1 between the punch surface of the lower second inner punch 34 and the punch surface of the lower second outer punch 32.

  As described above, the raw powder M is obtained by pre-compression corresponding to h2 on the upper punch group side (upper inner punch 42) and pre-compression corresponding to h1 on the lower punch group side (lower second inner punch 34). The portions around the core rod 20, that is, the portions corresponding to both end faces of the female screw portion of the shaft hole after molding are pre-compressed, and the density is locally increased.

  After the above pre-compression, as shown in FIG. 4, the fluid pressure cylinder 41a is driven to lower the upper and outer punches 40 so that the punch surfaces of the upper and inner punches 42 and 40 are aligned. The raw material powder M is compressed. At the same time, the lower first punch 30 is raised relative to the die 10, and the lower second outer punch 32 and the punch surface are aligned while rotating the lower second inner punch 34 and relative to the die 10. To rise. At this time, the raw material powder M is compressed, but due to the side pressure in the inner diameter direction generated by this compression, the low density region of the boss portion after molding in which the filling depth of the raw material powder M is large, that is, the pre-compression molding A part of the powder flows in the central part of the female screw part of the rear shaft hole, and the flow of the raw material powder M causes the threaded part 20a of the core rod 20 to be perpendicular to the central part of the female screw part of the molded shaft hole. Due to the pressure, the density of the central part of the female screw part of the shaft hole after molding is increased. 4 schematically shows the flow direction of the raw material powder M as described above.

  Next, as shown in FIG. 5, the upper and outer punches 40 are lowered, and the upper and lower punches 40 are lowered and aligned with the upper and outer punches 40 while rotating. At the same time, the lower first punch 30 and the lower second outer punch 32 are raised relative to the die 10, and the lower second inner punch 34 is rotated and aligned with the lower second outer punch 32 with respect to the die 10. And finally, the final compression is performed to complete the molding of the molded body P1.

  After the molding, as shown in FIG. 6, the molded body P1 is held from above and below by the punch surfaces of the upper inner punch 42 and the upper and outer punches 40 and the punch surfaces of the lower second outer punch 32 and the lower second inner punch 34. In this state, the die 10 and the lower first punch 30 are simultaneously lowered (so-called hold-down), and the molded product P1 is extracted from the die hole of the die 10. Next, as shown in FIG. 7, a servo motor (not shown) is driven, and the worm wheel 22 is rotationally driven via the worm 24. By this rotation, the core rod 20 is extracted downward from the shaft hole of the molded body P, with the male screw portion 21a being moved downward with rotation by screw feed with respect to the female screw portion 23a. In this case, since the molded body P1 is expanded by the spring back when it is extracted from the die hole of the die 10, the diameter of the shaft hole of the molded body P is also increased, so that the core rod 20 is provided with the female thread portion of the molded body P1. It can be easily extracted from the shaft hole.

(Modifications 1 to 4) The above is a molded body P1 having a shape with a shaft hole with a female screw portion in FIG. 8B and a flange portion on the outer periphery on one end face side of the boss portion forming the shaft hole. Is applied to the nut-shaped molded product P0 in FIG. 9A, and molded products P2 to P4 having the same shapes as in FIGS. 9C to 9E.

  Here, when the nut-shaped molded body P0 of FIG. 8A is formed, as illustrated in FIG. 9A, the upper and outer punches 40 of FIG. The upper punch is composed of an upper / outer punch 40A corresponding to the upper / outer punch 40 and an upper / inner punch 42A corresponding to the upper / inner punch 42. The lower punch corresponds to the lower second outer punch 32. The outer pan 32A and the lower inner punch 34A corresponding to the lower second inner punch 34 are configured.

  That is, in this case, it is a method for forming a molded product P0 having a shaft hole with a female thread portion, and when the raw powder M is filled in the die cavity, the punch surface of the lower inner punch 34A is used as the punch of the lower outer punch 32A. Filled in a state of being arranged below the surface. At the time of compression molding, the upper inner punch 42A and the upper outer punch 40A are both lowered so that the punch surfaces of the punches come into contact with the raw material powder, and the lower inner punch 34A is rotated along the core rod side threaded portion 20a. The die 10 is raised relatively to align with the punch surface of the lower outer punch 32A, and the upper inner punch side female screw portion 42a is fitted to the core rod side screw portion 20a and along the core rod side screw portion 20a. The upper and lower punches 40A are lowered until they are flush with the upper and inner punches 42A, and are further lowered to project into the raw material powder M in the die cavity. After the punch surfaces of the upper and inner punches 42A are aligned, the upper and outer punches 4A are further lowered and the upper and outer punches 4A are rotated while the upper and inner punches 42A are rotated. The lower outer punch 32A is further lowered relative to the die 10 and aligned with the lower outer punch 32A while rotating the lower inner punch 34A. Raise and perform molding. Further, at the time of releasing the molded body after compression molding, the molded body P0 in the die cavity is sandwiched between the upper inner punch 42A, the upper outer punch 40A, the lower inner punch 34A, and the lower outer punch 32A. After the extraction, the servo motor (not shown) is driven to rotate the worm wheel 22 through the worm 24. Thereby, the core rod 20 is extracted from the shaft hole of the molded product P0 by moving the male screw portion 21a downward with rotation by screw feed with respect to the female screw portion 23a.

  Further, when molding a molded body P2 having a flange portion formed on the outer periphery of the intermediate portion of the boss portion in FIG. 8C, as illustrated in FIG. The punch 40 is a multistage punch, and the upper punch group is composed of an upper first punch 401 for forming the flange portion of the molded body P2, an upper second outer punch 40B and an upper second inner punch 42B for forming the boss portion. The raw material powder between the upper first punch 401 and the lower first punch 30 can be obtained by the above-described forming procedure after being transferred as conventionally performed.

  That is, in this case as well, it is a method of forming a molded body P2 having a shaft hole with an internal thread portion, and when the raw material powder M is filled in the die cavity, the punch surface of the lower inner punch 34 is used as the punch of the lower outer punch 32. Filled in a state of being arranged below the surface. At the time of compression molding, the upper first punch 401 and the upper second inner punch 42B and the upper second outer punch 40B are both lowered to bring the punch surface of each punch into contact with the raw material powder, and the lower second inner punch 34 is While rotating along the core rod side screw portion 20a, the die 10 is raised relative to the die 10 to align with the punch surface of the lower second outer punch 32, and the upper inner punch side female screw portion 42a is aligned with the core rod side screw portion 20a. , While being rotated along the core rod side threaded portion 20a, it is further lowered to project into the raw material powder M in the die cavity and pre-compressed, and then the upper second outer punch 40B is After the two second inner punches 42B are lowered and the punch surfaces of the upper second outer punch 40B and the upper second inner punch 42B are aligned, the upper first punch 401 and the upper second outer pad are aligned. And further lowering the upper second inner punch 42B while rotating the upper second inner punch 42B and simultaneously lowering the lower second outer punch 32 relative to the die 10. Then, the lower second inner punch 34 is rotated and aligned with the lower second outer punch 32 to be raised relative to the die 10 to perform molding. Further, at the time of releasing the molded body after compression molding, it is extracted from the die 10 while being sandwiched between the upper second inner punch 42B and the upper second outer punch 40B, the lower second inner punch 34A and the lower second outer punch 32A. Thereafter, a servo motor (not shown) is driven to rotate the worm wheel 22 via the worm 24. Thus, the core rod 20 is extracted from the shaft hole of the molded product P2 by moving the male screw portion 21a downward with the rotation by screw feed with respect to the female screw portion 23a.

  Further, in the case of forming a molded body P3 having a convex portion in which the outer peripheral portion of the flange portion in FIG. 8 (d) becomes higher on one side, as illustrated in FIG. 9 (c), the lower first punch 30 in FIG. Is a multi-stage punch, and the lower punch group is formed of a lower first punch 301 for forming a raised portion (convex portion) of the flange portion and a lower portion for forming a flange portion corresponding to the lower first punch 30 in FIG. 2 punch 30B, and a lower third outer punch 32B for forming the boss portion corresponding to the lower second outer punch 32 in FIG. 1 and a lower third inner punch 34B corresponding to the lower second inner punch 34 in FIG. In addition, it can be obtained by the molding procedure as described above.

  That is, also in this case, the molding method of the molded body P3 having the shaft hole with the female thread portion, and when the raw material powder M is filled in the die cavity, the punch surface of the lower third inner punch 34B is placed on the lower third outer surface. Filling is performed in a state of being disposed below the punch surface of the punch 32. At the time of compression molding, the upper inner punch 42 and the upper outer punch 40 are both lowered to bring the punch surface of each punch into contact with the raw material powder, and the lower third inner punch 34B is rotated along the core rod side screw portion 20a. The die 10 is raised relatively to align with the punch surface of the lower third outer punch 32B, and the upper inner punch side female screw portion 42a is fitted to the core rod side screw portion 20a, and the core rod side screw portion 20a. , And further pre-compressed by projecting into the raw material powder M in the die cavity, and then lowering the upper and outer punches 40 until they are flush with the upper and inner punches 42, After the punch surfaces of the punch 40 and the upper and inner punches 42 are aligned, the upper and outer punches 40 are further lowered and aligned with the upper and outer punches 40 while rotating the upper and inner punches 42. At the same time, the lower first punch 301 and the lower third outer punch 32B are raised relative to the die 10, and the lower third inner punch 34B is rotated and aligned with the lower third outer punch 32B. The molding is carried out by raising the angle relative to 10. Further, at the time of releasing the molded body after compression molding, after the upper inner punch 42 and the upper outer punch 40 are extracted from the die 10 in a state of being sandwiched between the lower third inner punch 34B and the lower third outer punch 32B, A servo motor (not shown) is driven to rotate the worm wheel 22 via the worm 24. Thereby, the core rod 20 is extracted from the shaft hole of the molded product P3 by moving the male screw portion 21a downward with the rotation by screw feed with respect to the female screw portion 23a.

  Further, when forming a molded product P4 with a tooth groove having a longitudinal groove or a tooth groove formed on the outer periphery as shown in FIG. 8E, first, as illustrated in FIG. The hole is formed into a tooth groove shape, and the upper punch that is slidably fitted to the die hole of the die 10 is divided into an upper and outer punch 40C and an upper inner punch 42C, and is slidably fitted to the die hole of the die 10. The lower punch to be combined is divided into a lower outer punch 32C and a lower inner punch 34C, and the groove is formed only on the outer peripheries of the upper outer punch 40C and the lower outer punch 32C, corresponding to the tooth groove shape. It can be obtained by the following molding procedure.

  That is, in this case as well, a method of forming a molded body P4 having a shaft hole with a female thread portion, and when the raw powder M is filled in the die cavity, the punch surface of the lower inner punch 34C is used as the punch of the lower outer punch 32C. Filled in a state of being arranged below the surface. At the time of compression molding, the upper inner punch 42C and the upper outer punch 40C are both lowered to bring the punch surface of each punch into contact with the raw material powder, while rotating the lower inner punch 34C along the core rod side screw portion 20a. The die 10 is raised relatively to align with the punch surface of the lower outer punch 32C, and the upper inner punch side female screw portion 42a is fitted to the core rod side screw portion 20a and along the core rod side screw portion 20a. The upper and lower punches 40C are further lowered to project into the raw material powder M in the die cavity and pre-compressed. Then, the upper and outer punches 40C are lowered until they are aligned with the upper and inner punches 42C. After the punch surfaces of the upper and inner punches 42C are aligned, the upper and outer punches 4C are further lowered and the upper and outer punches 4C are rotated while rotating the upper and inner punches 42C. The lower outer punch 32C is raised relative to the die 10 at the same time, and at the same time, the lower inner punch 34C is rotated and aligned with the lower outer punch 32C while being relatively relative to the die 10. Raise and perform molding. Further, at the time of releasing the molded body after compression molding, the molded body P4 in the die cavity is sandwiched between the upper inner punch 42C and the upper outer punch 40C and the lower inner punch 32C and the lower outer punch 32C. After the extraction, the servo motor (not shown) is driven to rotate the worm wheel 22 through the worm 24. Thereby, the core rod 20 is extracted from the shaft hole of the molded product P4 by moving the male screw portion 21a downward with the rotation by screw feed with respect to the female screw portion 23a.

  In addition to the above modifications, for example, in the case of FIG. 8D, the shape of the molded body in which the flange portion is arranged in the middle of the boss portion as in FIG. 8C, or FIGS. 8B and 8C. In the case of (d), the outer periphery is made into a gear shape as in (e), or the flange portion is made into a hollow shape, etc. It is possible.

(Modification 5) FIG. 10 shows an example of a molding die apparatus having an upper core rod corresponding to FIG. In this description, the same members and parts as those in the above embodiment are denoted by the same reference numerals and redundant description is omitted. That is, in the molding die apparatus of FIG. 10, the upper core rod 48 and the configuration related thereto are changed as compared with the apparatus of FIG.

  The upper core rod 48 has a threaded portion 48a formed on the outer periphery on the lower end side desired for the die hole of the die 10, and a male threaded portion 49a formed on the outer periphery on the upper end side. The threaded portion 48 a has the same thread groove shape as the threaded portion 20 a of the core rod 20. The male threaded portion 49 a is provided on the outer periphery of the large-diameter portion 49 with a larger-diameter portion 49 provided on the lower end side outer periphery of the core rod 48.

  Further, in this structure, the cylinder / holding member 41A is provided with an arrangement space 41b defined on the upper side of the fluid pressure cylinder 41a as compared with the above-described configuration, and further provided on the upper side of the arrangement space 41b with the upper punch plate 46. And an upper arrangement space 41c partitioned therebetween. In the arrangement space 41b, a worm wheel 43 constituting rotation driving means is rotatably supported by upper and lower inner walls defining the arrangement space 41b via upper and lower bear link mechanisms 45, etc. The core rod 48 is inserted like a skewer from a through hole formed at the center. The upper arrangement space 41c is provided with a rotation driving means for rotatably supporting the core rod 48. That is, this rotational drive means is an example of a worm gear mechanism including a worm wheel 50 and a worm 52. The worm wheel 50 integrally has a guide tube portion 51 provided at the center, and is supported rotatably on the upper and lower inner walls that define the arrangement space 41c via the upper and lower bearing mechanisms 53 and the like. ing. The guide tube portion 51 has a female screw portion 51a screwed with the male screw portion 49a on the inner periphery.

  The worm wheel 50 supports the upper core rod 48 so that it can be screwed in a state in which the male screw portion 49a is screwed into the female screw portion 51a of the guide tube portion 51. The worm 52 meshes with the worm wheel 50 and rotates the worm wheel 50 forward or reverse by driving a servo motor (not shown). The upper core rod 48 guides the rotation and vertical driving of the upper inner punch 42 to reliably prevent, for example, the raw material powder M from sticking out and stably perform the compression formation. As described above, the present invention only has to substantially include the configuration specified in the claims, and the details can be further changed with reference to the above-described embodiments and modifications.

It is a schematic diagram which shows the example of a shaping die apparatus of this invention form, and is a shaping die apparatus suitable when shape | molding the molded object P1 of FIG.8 (b). It is a schematic diagram which shows the filling state of raw material powder among the shaping | molding methods in the case of shape | molding the molded object of FIG.8 (b) using the shaping die apparatus of FIG. It is a schematic diagram which shows the state which pre-compressed the raw material powder from the powder filling state of FIG. It is a schematic diagram which shows the intermediate state of the raw material powder compression process after the precompression of FIG. It is a schematic diagram which shows the final state of the compression process of raw material powder from the state of FIG. It is a schematic diagram which shows the state which extracted the molded object from the die | dye from the state of FIG. It is a schematic diagram which shows the state which completed extraction of the core rod from the state of FIG. (A)-(e) is a schematic diagram which shows the example of a shape of the molded object which has the axial hole with an internal thread part which concerns on this invention. 8A shows the molded body of FIG. 8A, FIG. 8B shows the molded body of FIG. 8C, FIG. 8C shows the molded body of FIG. 8D, and FIG. FIG. 6 is a schematic diagram of a main part illustrating a molding die apparatus suitable for molding a molded body of FIG. 5 corresponding to FIG. 5. It is a schematic diagram which shows the example of a shaping die apparatus provided with the upper core rod corresponding to FIG. It is a schematic diagram which shows the shaping die apparatus and shaping | molding method which are disclosed by patent document 1. FIG.

Explanation of symbols

10 ... Dice (11 is a die plate)
20 ... Core rod (20a is a threaded portion, 21a is a male threaded portion)
30, 301 ... lower first punch 30B ... lower second punch 32 ... lower second outer punch (corresponding to lower outer punch)
32A, 32C ... lower outer punch 32B ... lower third outer punch (corresponding to lower outer punch)
34 ... Lower second inner punch (corresponding to the lower inner punch, 34a is a female thread portion)
34A, 34C ... Lower inner punch (34a is female threaded part)
34B: Lower third inner punch (corresponding to the lower inner punch, 34a is an internal thread portion)
22, 50 ... Worm wheel (rotation drive means)
35, 43 ... Worm wheel (rotation drive means)
24, 52 ... Worm (rotation drive means)
36, 44 ... Worm (rotation drive means)
40, 40A, 40C ... upper and outer punch 40B ... upper second outer punch 41, 41A ... holding member (41a is a fluid pressure cylinder, 41b and 41c are arrangement spaces)
42, 42A, 42C ... upper inner punch (42a is an internal thread part)
42B ... Upper second inner punch (42a is an internal thread portion)
401 ... Upper first punch 48 ... Upper core rod (48a is a threaded portion, 49a is a male threaded portion)

Claims (5)

The die cavity formed by the die hole, the lower punch or the lower punch group, and the core rod for forming the shaft hole is filled with the raw material powder, and the upper punch or the upper punch group and the lower punch or the lower punch group are used as the raw material. A molding die device for a molded body having a shaft hole with a female thread portion for compression molding powder,
A threaded portion formed on the upper outer periphery of the core rod;
Rotation drive means for rotating the core rod in a screw feedable state;
Of the upper punch or upper punch group, upper and lower punches surrounding the upper punch and the upper and outer punches formed by dividing the upper punch slidingly contacting the core rod,
An internal thread portion that is formed on the inner peripheral surface of the upper inner punch and is slidably fitted to the upper outer periphery thread portion of the core rod;
Rotation drive means that rotates while supporting the upper inner punch,
Of the lower punch or the lower punch group, a lower inner punch formed by dividing a lower punch that is in sliding contact with the core rod, and a lower outer punch surrounding the lower punch,
A female thread portion formed on the inner circumferential surface of the lower inner punch and slidably fitted to the upper outer circumferential thread portion of the core rod;
A molding die apparatus for a molded body having a shaft hole with a female screw part, comprising: a rotation driving means that rotates while supporting the lower inner punch.   An upper core rod that is slidably fitted to the female threaded portion of the upper inner punch and forms a threaded portion that is continuous with the threaded portion of the core rod, and the upper core rod can be screw-fed The molding die apparatus for a molded body having a shaft hole with a female thread portion according to claim 1, further comprising a rotation driving means that rotates. A method for forming a molded body having a shaft hole with a female thread using the molding die device according to claim 1,
At the time of filling the raw powder to the die cavity, the punch surface of the lower inner punch is filled in a state arranged below the punch surface of the lower outer punch,
At the time of the compression molding, the upper inner punch and the upper and outer punches are both lowered to bring the punch surface of each punch into contact with the raw material powder, and the lower inner punch is rotated along the core rod side thread portion. The upper inner punch side female screw portion is fitted to the core rod side screw portion, and is aligned with the core rod side screw portion. Rotate and further lower and project into the raw powder in the die cavity and pre-compress,
Next, the upper and outer punches are lowered until they are aligned with the upper and inner punches, and after the punch surfaces of the upper and outer punches and the upper and inner punches are aligned, the upper and outer punches are further lowered and the While rotating the upper inner punch, the lower outer punch is further lowered to align with the upper and outer punches, and at the same time, the lower outer punch is raised relative to the die, and the lower outer punch is rotated while rotating the lower inner punch. A method for forming a formed body having a shaft hole with a female thread portion, wherein the forming is performed by aligning and raising the die relatively to the die.   At the time of releasing the molded body after the compression molding, the molded body in the die cavity is extracted from the die in a state of being sandwiched between the upper inner punch and the upper outer punch and the lower inner punch and the lower outer punch. 4. The method for molding a molded body having a shaft hole with an internal thread according to claim 3, wherein the core rod is extracted from the molded body while rotating.   5. The method for forming a formed body having a shaft hole with a female thread according to claim 3 or 4, wherein the upper core rod according to claim 2 guides rotation and vertical driving of the upper inner punch.

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