JP2007162090A - Molding die - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a molding die capable of easily forming a sintered compact or a green compact having an undercut shape without requiring complicated dies and many processes. <P>SOLUTION: In the molding die provided with a plurality of cores arranged at the spaces of annularly formed moldings having the spaces along the circumferential direction, each space has an opening with an undercut part to the direction into which each core 13 is inserted when the core 13 is arranged, and the core 13 is divided into a plurality of pieces along the circumferential direction and is composed of: an intermediate core 16 formed into a shape in which the width in the circumferential direction is not narrower than the projecting width in the circumferential direction of the undercut part and the insertion width is not changed in the insertion direction; and external cores 14, 15 formed into a shape excepting the intermediate core 16 from the planar shape of the space in such a manner that the width in the circumferential direction is not wider than the opening so as to be freely insertable from the opening to the space. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a molding die, and more particularly, to a molding die having a core corresponding to a molded body having an undercut portion.

Conventionally, a metal powder molded body is usually produced by a powder press method or an injection molding method, and the produced molded body is sintered under an appropriate temperature, atmosphere, and pressure, and further, depending on the application and purpose. Heat treatment is performed to make a product. When molding into a shape having a hollow or undercut, any method employs a means for forming a hollow portion using a core or a core rod during molding and removing the core and the core rod after molding. In order to remove the core, for example, the core is melted out or lost in a low temperature range that does not hinder sintering shrinkage during sintering.
JP-A-5-320718

However, when molding into a shape having a hollow or undercut using a core, the molding process becomes complicated, and various means have to be taken to remove the core after molding ( Patent Document 1).
In other words, conventionally, when forming a sintered body or compacted body having an undercut shape, a slide core is used for the outer shape, or sintering is divided into multiple times. Since a mold and many processes are required, it is inevitable that productivity is reduced and costs are increased.
An object of the present invention is to provide a molding die that can easily form a sintered body or a compacted body having an undercut shape without requiring a complicated mold or many processes. .

  In order to achieve the above object, a molding die according to the present invention comprises a plurality of cores arranged in the space of a molded body that is formed in an annular shape and has a plurality of spaces along the circumferential direction. In the mold, each space includes an opening having an undercut portion with respect to a direction in which the core is inserted when the core is disposed, and the core is divided into a plurality along the circumferential direction. A first split core piece formed in a shape in which a direction width is not narrower than a circumferential projecting width of the undercut portion and the insertion width does not change in the insertion direction; and the first split core piece from the planar shape of the space It is characterized by comprising at least one second split core piece having a shape excluding and having a circumferential width not wider than the opening so as to be inserted into the space from the opening.

  According to the present invention, the molding die having a plurality of cores arranged in the space of the molded body formed in an annular shape and having a plurality of spaces along the circumferential direction, each space has a core. Provided with an opening having an undercut portion with respect to the direction in which the core is inserted when arranged, and the core is divided into a plurality along the circumferential direction, and the circumferential width is not narrower than the circumferential protruding width of the undercut portion. The first divided core piece formed in a shape in which the insertion width does not change in the insertion direction, the shape obtained by excluding the first divided core piece from the planar shape of the space, and the circumferential width so that it can be inserted into the space from the opening Is formed of at least one second divided core piece formed not wider than the opening. Thereby, it is possible to easily form a sintered body or a green compact having an undercut shape without requiring a complicated mold or many processes.

The best mode for carrying out the present invention will be described below with reference to the drawings.
1A and 1B show a molding die according to an embodiment of the present invention, in which FIG. 1A is a cross-sectional explanatory view along a mold opening direction, and FIG. 1B is a cross-sectional explanatory view along a BB line in FIG. is there. As shown in FIG. 1, the molding die 10 has an upper die 11 and a lower die 12 that bisect the entire die up and down, and a core 13 for forming a space inside the die (( a)).

  The core 13 includes three outer cores (second split core pieces) 14 and 15, and an intermediate core (first split core piece) 16 sandwiched between the outer cores 14 and 15. , 15 are held by fixing members 18, 19 (see (b)) attached to the core holding member 17 of the upper die 11. The core holding member 17 is detachably attached to the upper mold 11 and the fixing members 18 and 19 are detachably attached to the core holding member 17, respectively. Further, the core holding member 17 corresponds to the outer shape of the intermediate core 16 that can take out the intermediate core 16 from the outside of the upper mold 11 and can be sealed when the intermediate core 16 is mounted. A through hole 17a is opened.

The molding die 10 is a die for forming a sintered body or a green compact, and the finished molding 20 is a single-opening direction (a direction in which the upper die 11 and the lower die 12 are separated from each other). It has the undercut part 21 used as an undercut shape with respect to the arrow A of (a) (refer (b)). An example of such a molded body is a rotor core that forms a rotor of a rotating electrical machine.
2 shows the molded body and the core of FIG. 1, (a) is a perspective view when the molded body has an outer peripheral wall, and (b) is a perspective view when the molded body has an inner and outer peripheral wall. 3A and 3B show a procedure for removing the core from the molded body, wherein FIG. 3A is an explanatory view when the intermediate core is pulled out, FIG. 3B is an explanatory view after the intermediate core is pulled out, and FIG. It is explanatory drawing at the time.

  As shown in FIGS. 2 and 3, the molded body 20 is formed in an annular shape, has a plurality of wall portions 22 that are spaced apart at substantially equal intervals in the circumferential direction and project along the radial direction. The undercut portions 21 having an undercut shape in the molded body surface direction are provided on both sides of the upper end circumferential direction of 22. Moreover, the molded object 20 has the outer peripheral wall 23 formed in the same height as the wall part 22 over the whole outer periphery. That is, between the adjacent wall portions 22, there is a recessed space that is surrounded by both wall portions 22 and the outer peripheral wall 23 and opens on the surface side (arrow A direction side in the drawing) and the inner peripheral side. Formed (see FIG. 2).

  When the molded body 20 is formed by the molding die 10, the cores 13 including the outer cores 14 and 15 and the intermediate core 16 positioned therebetween are arranged at a plurality of locations inside the molding die 10. When the core 13 is arranged, the intermediate core 16 is sandwiched between the outer cores 14 and 15 so as to be in close contact with each other, and are arranged in a line along the circumferential direction of the molded body (see FIGS. 2 and 3). As a result, a plurality of wall forming spaces formed by the adjacent cores 13 are provided in the molding die 10.

  The outer core 14 and the outer core 15 are each formed with an inclined upper side 14a and an inclined side 15a aligned with the undercut portion 21 of the wall portion 22 in the circumferential direction of the molded body (FIG. 3C). reference). The intermediate core 16 has a molded body circumferential length (width) that is not narrower than the molded body circumferential protrusion width a of the undercut portion 21 (see FIG. 3A), and between the outer cores 14 and 15. The width of the molded body in the circumferential direction in which the insertion width does not change in the insertion direction is equal on the inner and outer circumferential sides (see FIGS. 2 and 3).

  The core 13 composed of the outer cores 14 and 15 and the intermediate core 16 fixes the outer core 14 to the fixing member 18 and the outer core 15 to the fixing member 19 (see FIG. 1B). The intermediate core 16 is sandwiched between the outer cores 14 and 15 so as to be arranged and fixed at a predetermined position inside the mold. Then, the upper mold | type 11 and the lower mold | type 12 are closed, and the sintering or the compacting process by the shaping die 10 is performed.

  After completion of the sintering or compacting process, first, the fixing member 18 is removed from the outer core 14, the fixing member 19 is removed from the outer core 15, and then the intermediate core 16 is opened in the mold opening direction (see arrow A). ) (See FIG. 3A). Next, after opening the mold and removing the upper mold 11 from the lower mold 12, both outer cores 14 and 15 are moved closer to each other and moved to a space formed after the intermediate core 16 is pulled out (FIG. 3). (See (b)). Both outer cores 14 and 15 move to the space after the intermediate core 16 is pulled out, so that they can be removed from the undercut portion 21 of the molded body 20 and can be taken out while avoiding the undercut portion 21. Thereafter, the outer cores 14 and 15 are pulled out in the mold opening direction and taken out from the molded body 20 (see FIG. 3C), thereby completing the molding.

  When the outer cores 14 and 15 are taken out from the molded body 20, they are pulled out in the mold opening direction, and the molded body 20 is open on the inner peripheral side (see FIG. 2 (a)). Is possible. Also at this time, after the intermediate core 16 is pulled out, the outer cores 14 and 15 are sequentially moved to the space after the intermediate core 16 is pulled out and pulled out. In addition, when the molded object 20 has the inner peripheral wall 24 in addition to the outer peripheral wall 23 (refer FIG.2 (b)), both the outer cores 14 and 15 are pulled out to the molded object surface side upper direction which is a mold opening direction.

  4 shows a specific example in which the core of FIG. 3 is pulled out, (a) is an explanatory view when the intermediate core is pulled up, (b) is an explanatory view when both outer cores are approached, and (c) is an outer center. It is explanatory drawing at the time of a child raising. As shown in FIG. 4, the outer cores 14 and 15 and the intermediate core 16 are integrated by a connecting member 25. The connecting member 25 is formed by connecting one end 25a of two plate-like arm portions so as to be rotatable via a shaft portion 26 having a hinge function, and each other end 25b is formed by an outer core. 14 and the upper end mounting portions 14b and 15a of the outer core 15 are rotatably mounted. The shaft portion 26 is slidably mounted in a long hole 16a that is opened in the intermediate core 16 along the vertical axis direction.

Thus, when the outer cores 14 and 15 and the intermediate core 16 are integrated by the connecting member 25, the outer cores 14 and 15 are formed in conjunction with the withdrawal of the intermediate core 16 as shown below. It can be removed from the body 20.
After completion of the sintering or compacting process, when the intermediate core 16 is pulled upward from the core holding member 17 in the mold opening direction (see arrow A) (see FIG. 4A), the shaft portion 26 is , It contacts the lower end of the long hole 16a. Further, when the intermediate core 16 is pulled out, the shaft portion 26 also moves upward together with the intermediate core 16, and the two plate-like arm portions of the connecting member 25 approach each other as the shaft portion 26 moves upward ( (See (b)).

As the two plate-like arm portions approach each other, the outer cores 14 and 15 move to the space after the intermediate core 16 is pulled out. Both outer cores 14 and 15 move to the space after the intermediate core 16 is pulled out, so that they can be removed from the undercut portion 21 of the molded body 20 and can be taken out while avoiding the undercut portion 21.
Thereafter, when the extraction of the intermediate core 16 is continued, the outer cores 14 and 15 are further brought into close contact with each other, and the both outer cores 14 and 15 brought into close contact with each other are pulled upward together with the intermediate core 16. And taken out from the molded body 20 (see (c)). When the outer cores 14 and 15 move upward, the core holding member 17 also moves upward together.

5A and 5B show a molding die according to another embodiment of the present invention, in which FIG. 5A is a cross-sectional explanatory view along the mold opening direction, and FIG. 5B is a cross-sectional explanatory view along the BB line in FIG. It is. 6 shows a molded body formed by the molding die of FIG. 5, (a) is a perspective view of the molded body with the core mounted thereon, and (b) shows the core of (a) in FIG. 2. It is perspective explanatory drawing of the state used for the molded object of (a).
As shown in FIG. 5, the molding die 30 has an upper die 31 that is not equipped with a core holding member 17 from which the intermediate core 16 can be taken out, instead of the upper die 11. The lower mold 35 includes a core 32 and a core 33 instead of the 15 and the intermediate core 16, and further includes a core holding member 34 that holds both the cores 32 and 33 instead of the lower mold 12. have. Other configurations and operations are the same as those of the molding die 10.

As shown in FIG. 6, in the molded body 36 formed by the molding die 30, the undercut portion 21 of the wall portion 22 is not provided, and the surface side that is the air gap side is between the adjacent wall portions 22. It has a horizontal hole-shaped space 37 that is closed without opening and opens only the inner peripheral side end face (see (a)). Other configurations and operations are the same as those of the molded body 20.
Both the cores 32 and 33 are a rectangular core (first divided core piece) 32 and a fan-shaped core (second divided core piece) 33 obtained by dividing the core 13 into two along the circumferential direction of the molded body. (See FIG. 6B). The rectangular core 32 has a rectangular shape that is not wider than the opening 37a of the space 37 and has an equal rectangular shape on the inner and outer peripheral sides where the insertion width does not change in the insertion direction into the space 37. The child 33 has a fan shape obtained by removing the rectangular core 32 from the planar shape of the space 37.

That is, at least one of the two core pieces constituting the core 13 may be configured to have a parallel or undercut angle α to a side of the space 37 having a planar undercut shape (see FIG. 6 (b)). And the fan-shaped core 33 is formed so that the circumferential width of the outer peripheral side edge is not wider than the opening 37a so that it can be inserted into the space 37 from the opening 37a.
Both the cores 32 and 33 are positioned and arranged at predetermined positions in the mold, and are then incorporated into the lower mold 35 while being held by the core holding member 34 fixed via the fixing member 34a.

When the molded body 36 is formed by the molding die 30 and the rectangular core 32 and the fan-shaped core 33 are taken out from the molded body 36, the upper mold 31 is first removed by opening the mold and the core holding member is removed from the lower mold 32. After removing 34, the molded body 36 and the cores 32 and 33 are released. Thereafter, as shown in FIG. 6, the rectangular core 32 is pulled out from the opening 37a (see (a) arrow a), and then the fan-shaped core 33 is pulled out from the opening 37a (see (a) arrow b). Both cores 32 and 33 are removed from the molded body 36.
In addition, the core 13 which consists of two of the rectangular core 32 and the fan-shaped core 33 is the molded object 20 in which the recessed part which the surface side and an inner peripheral side open among the both wall parts 22 and the outer peripheral walls 23 was formed. (See FIG. 2A) (see FIG. 2B).

As described above, in the molding die having a plurality of cores arranged in the space of the molded body that is formed in an annular shape and has a plurality of spaces along the circumferential direction, each space includes the core. Provided with an opening having an undercut portion with respect to a direction in which the core is inserted, and the core is divided into a plurality along the circumferential direction, and the circumferential width projects in the circumferential direction of the undercut portion. A first split core piece formed in a shape that is not narrower than the width and does not change the insertion width in the insertion direction, a shape obtained by removing the first split core piece from the planar shape of the space, and the opening from the opening It comprises at least one second divided core piece formed so as to be inserted into the space and having a circumferential width not wider than the opening.
As a result, it is not necessary to provide a slide core that has a complicated structure and a high pressure for the mold for closing the mold, and a core that can be divided and assembled is used. A knot and a green compact can be formed.

Further, the opening is provided on the inner peripheral surface side and the surface side of the molded body, and the first divided core piece is composed of one piece that is finally disposed at the center when the core is disposed, and the second The split core piece is composed of two pieces arranged on both sides of the first split core piece. Further, the opening is provided only on the inner peripheral surface side of the molded body, and the first divided core piece is composed of one piece arranged last when the core is arranged, and the second divided core piece is provided. Consists of one piece arranged adjacent to the first split core piece.
Thereby, it is possible to provide a sintered body having an undercut shape and a compacted body more easily by die-cutting a plurality of divided core pieces in order, and an undercut portion and By opening the core piece having a parallel surface first and then opening the remaining core piece, an undercut-shaped sintered compacted body is obtained in the same manner as described above. This is particularly effective when the undercut shape is a thin wall type.

Further, the first divided core piece and the two second divided core pieces are formed in an elongated hole formed in the first divided core piece along the drawing direction of the first divided core piece. A first moving shaft portion; two arm portions each having one end rotatably connected to the shaft portion and the other end mounted on each second split core piece; When the split core piece is pulled out and the shaft portion reaches the lower end of the elongated hole, the first split core piece is separated from between the second split core pieces and is connected by a connecting member. .
As a result, when the first split core piece is moved in the mold opening direction, first, the first split core piece is removed from the undercut contact core set (during this time, it is coupled to the undercut contact core). The hinge connecting portion slides in the long hole portion), and subsequently, the core assembly moves to the center as the connecting portion moves upward to avoid the undercut portion, and then moves in the mold opening direction. Thereby, an undercut shape can be easily obtained by mold opening in one direction.

  Thus, according to the present invention, the molding die having a plurality of cores arranged in the space of the molded body formed in an annular shape and having a plurality of spaces along the circumferential direction has each space An opening having an undercut portion with respect to the direction in which the core is inserted when the core is disposed, the core being divided into a plurality along the circumferential direction, and the circumferential width projecting in the circumferential direction of the undercut portion Can be inserted into the space from the opening in a shape in which the first divided core piece is formed in a shape that is not narrower than the width and does not change the insertion width in the insertion direction, and the first divided core piece from the planar shape of the space Since it is composed of at least one second split core piece whose circumferential width is not wider than the opening, an undercut shape can be easily formed without requiring a complicated mold or many processes. A sintered body or a compact formed body can be formed.

The molding die which concerns on one embodiment of this invention is shown, (a) is sectional explanatory drawing in alignment with a mold opening direction, (b) is sectional explanatory drawing in alignment with the BB line of (a). 1A and 1B show a molded body and a core of FIG. 1, wherein FIG. 1A is a perspective view when the molded body has an outer peripheral wall, and FIG. 1B is a perspective view when the molded body has an inner and outer peripheral wall. The procedure for removing the core from the molded body is shown, (a) is an explanatory diagram when the intermediate core is extracted, (b) is an explanatory diagram after the intermediate core is extracted, and (c) is an explanatory diagram when the both outer cores are extracted. It is. FIG. 3 shows a specific example in which the core is pulled out, (a) is an explanatory diagram when the intermediate core is pulled up, (b) is an explanatory diagram when the both outer cores are approached, and (c) is when the both outer cores are pulled up It is explanatory drawing. The molding die which concerns on other embodiment of this invention is shown, (a) is sectional explanatory drawing in alignment with a mold opening direction, (b) is sectional explanatory drawing in alignment with the BB line of (a). 5 shows a molded body formed by the molding die of FIG. 5, (a) is a perspective view of the molded body in a state where the core is mounted, and (b) shows the core of (a) in FIG. 2 (a). It is perspective explanatory drawing of the state used for the molded object.

Explanation of symbols

10, 30 Mold 11, 31 Upper mold 12, 35 Lower mold 13 Core 14, 15 Outer core 14 a, 15 a Inclined side 14 b, 15 b Upper end mounting portion 16 Intermediate core 16 a Long hole 17 Core holding member 17 a Through Hole 18, 19 Fixing member 20, 36 Molded body 21 Undercut portion 22 Wall portion 23 Outer peripheral wall 25 Connecting member 25a One end 25b Other end 26 Shaft portion 32 Rectangular core 33 Fan-shaped core 34 Core holding member 37 Space 37a Opening a Projection width in the circumferential direction

Claims (4)

In a molding die having a plurality of cores arranged in the space of the molded body formed in an annular shape and having a plurality of spaces along the circumferential direction,
Each space includes an opening having an undercut portion with respect to a direction in which the core is inserted when the core is disposed;
The core is divided into a plurality along the circumferential direction, and the first divided core piece is formed in a shape in which the circumferential width is not narrower than the circumferential protruding width of the undercut portion and the insertion width does not change in the insertion direction. And a shape obtained by removing the first split core piece from the planar shape of the space, and at least one first width formed so as to be inserted into the space from the opening so as not to be wider than the opening. A molding die comprising: a split core piece.   The opening is provided on the inner peripheral surface side and the front surface side of the molded body, and the first divided core piece is composed of one piece arranged last in the center when the core is arranged, 2. The molding die according to claim 1, wherein the core piece includes two pieces arranged on both sides of the first divided core piece.   The opening is provided only on the inner peripheral surface side of the molded body, and the first divided core piece is composed of one piece arranged last when the core is arranged, and the second divided core piece is 2. The molding die according to claim 1, comprising one piece disposed adjacent to the first divided core piece. The first split core piece and the two second split core pieces are:
A shaft portion that is opened in the first split core piece and moves in a long hole along the pulling direction of the first split core piece, and one end of each is rotatably connected to the shaft portion. Two arm portions attached to the second divided core pieces, and when the shaft portion reaches the lower end of the elongated hole by pulling out the first divided core pieces, 3. The molding die according to claim 2, wherein the first divided core pieces are connected by a connecting member that separates the first divided core pieces from between the second divided core pieces.

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