Apparatus for manufacturing powder molded bodies, and method for manufacturing powder molded bodies

Abstract

A powder molding apparatus comprising: a die having a hollow portion penetrating in a first direction; a first core inserted into the hollow portion along the first direction; an upper punch and a lower punch for compressing powder disposed in the hollow portion; and a drive mechanism for moving the first core along the first direction, wherein the first core has a projection protruding from its side surface in a direction intersecting the first direction; and the drive mechanism includes a cylinder for supplying power to the first core so as to move independently of the die, the upper punch, and the lower punch.

Description

Technical Field

[0001] The present disclosure relates to an apparatus for manufacturing a powder compact and a method for manufacturing a powder compact. This application claims priority based on Japanese Patent Application No. 2024-110531 filed on July 9, 2024, and incorporates by reference all the descriptions set forth in the Japanese application.

Background Art

[0002] Patent Document 1 discloses a mold for manufacturing a molded body having an undercut shape. This mold includes a first die, a second die, a first punch, and a second punch. The first punch is an upper punch, and the second punch is a lower punch. The second die is provided with an undercut forming portion for imparting an undercut shape to the molded body. The undercut forming portion includes, for example, a protrusion. The second die is inserted downward into the through-hole so that the outer surface of the second die contacts the inner surface of the through-hole of the first die. The molded body is manufactured by compressing the powder filled in the cavity formed by the inner surface of the through-hole of the first die, the second die, and the second punch with the first punch and the second punch. When compressing the powder, the lower end surface of the first punch and the upper end surface of the second die are engaged with each other.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] The apparatus for manufacturing a powder molded article according to the present disclosure comprises a die having a hollow portion penetrating in a first direction, a first core inserted into the hollow portion along the first direction, an upper punch and a lower punch for compressing powder disposed in the hollow portion, and a drive mechanism for moving the first core along the first direction. The first core has a projection protruding from its side surface in a direction intersecting the first direction. The drive mechanism includes a cylinder that provides power to the first core so as to move independently of the die, the upper punch, and the lower punch. [Brief explanation of the drawing]

[0005] [Figure 1] Figure 1 is a longitudinal cross-sectional view of a powder molding apparatus according to an embodiment, showing the upper punch, lower punch, first core, and second core in a state where they are not inserted into the die. [Figure 2] Figure 2 is a longitudinal cross-sectional view of a powder molding apparatus according to an embodiment, showing the lower punch, first core, and second core inserted into the die, but the upper punch not inserted into the die. [Figure 3] Figure 3 is a longitudinal cross-sectional view of the powder molding apparatus according to the embodiment, showing the state in which the upper punch is being lowered from the state shown in Figure 2. [Figure 4] Figure 4 is a longitudinal cross-sectional view of the powder molded body manufacturing apparatus according to the embodiment, showing the state in which the upper punch is further lowered from the state in Figure 3, compressing the powder with the upper and lower punches, and moving the first core to a predetermined position. [Figure 5] Figure 5 is a cross-sectional view of the powder molding apparatus shown in Figure 4. [Figure 6] Figure 6 is a longitudinal cross-sectional view of the powder molded body being removed from the manufacturing apparatus according to the embodiment. [Figure 7] Figure 7 is a perspective view of a powder molded body formed using the powder molded body manufacturing apparatus according to this embodiment. [Modes for carrying out the invention]

[0006] [Issues this disclosure aims to address] If the size of the undercut molding portion, for example, the amount of protrusion of the protrusion, is large, resistance from the powder will be applied downwards to the protrusion when the powder is compressed, which may prevent the second die from being pushed down to the correct position. If the second die is not in the correct position, the position of the undercut portion in the manufactured powder molded body will not be in the predetermined position. Also, if the second die is not in the correct position, the compression of the powder may be insufficient. As with the mold disclosed in Patent Document 1, if the lower end surface of the first punch and the upper end surface of the second die are engaged with each other, the second die will be forcibly pushed down even if resistance from the powder is applied downwards to the protrusion. However, if the lower end surface of the first punch and the upper end surface of the second die are engaged with each other, the first punch and the second die will move simultaneously, making it impossible to individually adjust the timing of moving the first punch and the timing of pushing down the second die. When the first punch and the second die move simultaneously, depending on the shape and size of the protrusion, the compression of the powder may be insufficient.

[0007] One of the objectives of this disclosure is to provide a powder molding apparatus that can manufacture powder moldings having an undercut shape with high precision and efficiency.

[0008] [Effects of this disclosure] The manufacturing apparatus for powder molded bodies described herein can manufacture powder molded bodies having an undercut shape with high precision and efficiency.

[0009] [Description of Embodiments in this Disclosure] First, the embodiments of this disclosure will be listed and described.

[0010] (1) A powder molding apparatus according to an embodiment of the present disclosure comprises: a die having a hollow portion penetrating in a first direction; a first core inserted into the hollow portion along the first direction; an upper punch and a lower punch for compressing powder disposed in the hollow portion; and a drive mechanism for moving the first core along the first direction. The first core has a projection protruding from its side surface in a direction intersecting the first direction. The drive mechanism includes a cylinder that provides power to the first core so as to move independently of the die, the upper punch, and the lower punch.

[0011] The first direction is the direction in which the upper and lower punches move relative to the die, and is the direction in which the powder is compressed. The first core is referred to as a core in this disclosure, but depending on the configuration of the powder molding apparatus, it may be a component commonly called a punch. The first core is a component that has a projection extending from its side in a direction intersecting the first direction and plays a role in imparting an undercut shape to the powder molding produced, and is not limited by its name.

[0012] In the powder molding apparatus of this disclosure, the first core can be moved along a first direction by a drive mechanism. Therefore, even if a resistance force from the powder is applied below the protrusion when the powder is compressed, the first core can be forcibly moved downward. By moving the first core, the protrusion is positioned appropriately when the powder is compressed. Thus, in the manufactured powder molding, the position of the undercut portion is set at a predetermined position with high precision. In the powder molding apparatus of this disclosure, the timing of moving the first core and the timing of moving the components other than the first core can be adjusted individually. If the timing of moving the first core can be adjusted individually, the powder can be compressed appropriately regardless of the shape and size of the protrusion of the first core.

[0013] (2) In the manufacturing apparatus of the powder compact described in (1) above, the first core is inserted into the hollow portion from the same direction as the lower punch, the drive mechanism includes a lower plate connected to the lower end of the first core, and the cylinder may move the lower plate along the first direction.

[0014] By the first core being interlocked with the lower plate, it is easy to forcibly move the first core downward.

[0015] (3) In the manufacturing apparatus of the powder compact described in (2) above, the upper end of the cylinder is supported by an upper plate connected to the upper end of the upper punch, and the lower end of the cylinder may be in contact with the lower plate.

[0016] By arranging the cylinder between the upper plate and the lower plate, the manufacturing apparatus of the powder compact can be miniaturized.

[0017] (4) In the manufacturing apparatus of the powder compact according to any one of (1) to (3) above, the upper end surface of the first core may be non-contact with the lower end surface of the upper punch.

[0018] If the upper end surface of the first core and the lower end surface of the upper punch are non-contact, the first core is not affected by the movement of the upper punch.

[0019] (5) In the manufacturing apparatus of the powder compact according to any one of (1) to (4) above, the first core may be inserted into the hollow portion so as to divide the hollow portion into a plurality of segments arranged in parallel in a direction orthogonal to the first direction.

[0020] When the hollow portion is divided into a plurality of segments, a plurality of powder compacts can be manufactured by a single compression. The protrusions of the first core are provided corresponding to each segment. Therefore, a powder compact having an undercut shape can be efficiently manufactured. When manufacturing a plurality of powder compacts by a single compression, the resistance force from the powder applied to the protrusions of the first core tends to increase. Since the first core can be moved in the first direction by the drive mechanism, the first core can be moved so that the protrusions are arranged at appropriate positions regardless of the magnitude of the resistance force.

[0021] (6) The manufacturing apparatus for the powder compact according to any one of (1) to (5) above may further include a second core inserted into the hollow portion in parallel with the first core.

[0022] When the second core is provided, the degree of freedom in the shape of the manufactured powder compact is increased. In particular, when the second core is provided, a powder compact having a through hole or a blind hole along the first direction can be manufactured.

[0023] (7) The method for manufacturing a powder compact according to an embodiment of the present disclosure includes a step of preparing a manufacturing apparatus for the powder compact according to any one of (1) to (6) above, a step of filling the powder into the hollow portion into which the first core and the lower punch are inserted, a step of compressing the powder with the upper punch and the lower punch to form a powder compact, and a step of relatively moving the die and the upper punch with respect to the lower punch to take out the powder compact. In the step of forming the powder compact, the first core is moved to a predetermined position by the drive mechanism.

[0024] In the method for manufacturing a powder compact of the present disclosure, since the manufacturing apparatus for the powder compact of the present disclosure is used, a powder compact having an undercut shape can be manufactured with high precision and efficiency.

[0025] [Details of Embodiments of the Present Disclosure] Specific examples of the apparatus for manufacturing powder molded articles of this disclosure and the method for manufacturing powder molded articles using the apparatus for manufacturing powder molded articles of this disclosure will be described with reference to the drawings. Identical reference numerals in the drawings indicate the same or corresponding parts. In each drawing, some parts of the configuration may be exaggerated or simplified for ease of explanation. The dimensional ratios of parts in the drawings may also differ from those of the actual components. However, the present invention is not limited to these examples and is indicated by the claims, and all modifications within the meaning and scope of the claims are intended to be included.

[0026] <Equipment for manufacturing powder-molded products> The powder molding apparatus 1 of this embodiment will be described with reference to Figures 1 to 5. For the powder molding body 10 produced by the powder molding apparatus 1, refer to Figures 6 and 7 as appropriate. The powder molding apparatus 1 comprises a die 2, an upper punch 3, a lower punch 4, and a first core 5. The powder molding apparatus 1 of this embodiment further comprises a second core 6.

[0027] In the powder molding apparatus 1 shown in Figure 1, the upper punch 3, lower punch 4, first core 5, and second core 6 are not inserted into the die 2. In the powder molding apparatus 1 shown in Figure 2, the lower punch 4, first core 5, and second core 6 are inserted into the die 2, but the upper punch 3 is not inserted into the die 2. As shown in Figure 1, the die 2 has a hollow section 20 that penetrates in the first direction D1. As shown in Figure 2, the first core 5 and second core 6 are inserted into the hollow section 20 in parallel to each other along the first direction D1.

[0028] Figure 3 shows the state in which powder 7P is filled into the hollow section 20 into which the lower punch 4, first core 5, and second core 6 are inserted in the die 2, and the upper punch 3 is being lowered. Figure 4 shows the state in which the upper punch 3 is lowered further from the state in Figure 3, compressing the powder 7P with the upper punch 3 and lower punch 4, and moving the first core 5 to a predetermined position. Figure 5 shows a cross-section of the die 2, upper punch 3, first core 5, and second core 6 in the powder molded body manufacturing apparatus 1 shown in Figure 4, cut by a plane perpendicular to the first direction D1 above the protrusion 55 of the first core 5. In Figure 5, the protrusion 55 is shown by a dashed line. Figure 6 shows the state in which the manufactured powder molded body 10 is removed. Figure 7 shows one of the powder molded bodies 10 manufactured by the powder molded body manufacturing apparatus 1.

[0029] The first core 5 is provided with a projection 55. The projection 55 protrudes from the sides 51, 52 of the first core 5 in a direction intersecting the first direction D1. The projection 55 imparts an undercut shape to the powder molded body 10 shown in Figures 6 and 7. As shown in Figure 2, a cavity is formed in the hollow portion 20 by the die 2, the lower punch 4, the first core 5, and the second core 6. In this example, the cavity has a first cavity 73 and a second cavity 74. The first cavity 73 and the second cavity 74 are filled with powder 7P as shown in Figure 3. The upper punch 3 and the lower punch 4 compress the powder 7P filled in the first cavity 73 and the second cavity 74 as shown in Figure 4, thereby producing a total of two powder molded bodies 10 (see Figure 6).

[0030] One of the features of the powder molded body manufacturing apparatus 1 of this embodiment is that it is equipped with a drive mechanism 8 that moves the first core 5 along the first direction D1. The drive mechanism 8 includes a cylinder 80 that provides power to the first core 5 so that it moves independently of the die 2, the upper punch 3, the lower punch 4, and the second core 6.

[0031] The first direction D1 is the direction in which the hollow portion 20 in the die 2 penetrates, as shown in Figure 1. The first direction D1 is the vertical direction. The first direction D1 is the direction in which the upper punch 3 and lower punch 4 move relative to the die 2, and is the direction in which the powder 7P is compressed. The second direction D2 shown in the drawing is perpendicular to the first direction D1, and is the direction in which the first core 5 and the second core 6 are aligned. The third direction D3 shown in the drawing is perpendicular to both the first direction D1 and the second direction D2. In the drawing, the first direction D1, the second direction D2, and the third direction D3 are indicated by single arrows. The opposite directions of the first direction D1, the second direction D2, and the third direction D3 are similarly referred to as the first direction D1, the second direction D2, and the third direction D3. Figures 1 to 4 show the manufacturing apparatus 1 for a powder molded body cut along a plane aligned with the first direction D1. In Figures 1 to 4, the cylinder 80 is shown in a side view for convenience of explanation.

[0032] Thailand As shown in Figure 1, die 2 is a cylindrical member having a hollow portion 20 that penetrates in a first direction D1. The hollow portion 20 has an end that opens upward and an end that opens downward. The hollow portion 20 is a space with both ends open. The shape of the hollow portion 20 corresponds to the outer shape of the powder molded body 10 that is compression molded. The inner surface 21 of die 2 is, for example, a smooth surface without irregularities. The opening edge of the hollow portion 20 as viewed from the first direction D1 may be a straight line, a curve, or a combination of multiple straight lines and curves. In this example, the shape of the opening edge is generally rectangular, as shown in Figure 5, and includes four straight lines and four curves.

[0033] Die 2 moves along the first direction D1 by a drive mechanism (not shown).

[0034] ≪Upper punch≫ The upper punch 3 is inserted into the upper part of the hollow section 20. If the hollow section 20 is divided into multiple segments 7 by the first core 5, which will be described later, multiple upper punches 3 are provided corresponding to the number of segments 7. In this example, the hollow section 20 is divided into a first segment 71 and a second segment 72, as shown in Figures 2 and 5. The first segment 71 and the second segment 72 are columnar spaces with a rectangular cross-section, as shown in Figure 5. One powder molded body 10 is produced in the first segment 71, and another powder molded body 10 is produced in the second segment 72. In this example, a total of two powder molded bodies 10 are produced, corresponding to the number of first segments 71 and second segments 72 (see Figure 6). In this example, the upper punch 3 comprises a first upper punch 31 and a second upper punch 32, corresponding to the first segment 71 and the second segment 72. If the hollow section 20 is not divided, there is one upper punch 3.

[0035] Each of the first upper punch 31 and the second upper punch 32 is a columnar or cylindrical member. In this example, each of the first upper punch 31 and the second upper punch 32 is a cylindrical member into which a portion of the second core 6, described later, is inserted. The outer shape of the end faces of each of the first upper punch 31 and the second upper punch 32 corresponds to the outer shape of the first end face 11 of the powder molded body 10 that is compression molded. In this example, the outer shape of the end faces of each of the first upper punch 31 and the second upper punch 32 is substantially rectangular. The substantially rectangular shape includes a range that can be considered substantially rectangular, including shapes with chamfered corners or shapes with rounded corners.

[0036] When the powder 7P shown in Figures 3 and 4 is compressed, a portion of the first core 5 is inserted between the first upper punch 31 and the second upper punch 32. The first upper punch 31 and the second upper punch 32 are positioned with a gap that allows a portion of the first core 5 to slide freely.

[0037] In this example, the first upper punch 31 and the second upper punch 32 are each provided with a through hole 34. A portion of the second core 6, which will be described later, is slidably inserted into the through hole 34.

[0038] Each of the first upper punch 31 and the second upper punch 32 slides along the first direction D1 relative to the die 2, the first core 5, and the second core 6.

[0039] The first upper punch 31 and the second upper punch 32 move along a first direction D1 by a drive mechanism (not shown). The drive mechanism includes, for example, a ram. The first upper punch 31 and the second upper punch 32 may operate in conjunction with each other. For example, the upper ends of the first upper punch 31 and the upper ends of the second upper punch 32 are connected to an upper plate 37, and the upper plate 37 is connected to a drive mechanism (not shown). As the upper plate 37 moves along the first direction D1 by the drive mechanism, the first upper punch 31 and the second upper punch 32 move simultaneously along the first direction D1 in conjunction with the upper plate 37.

[0040] The first upper punch 31 and the second upper punch 32 may move independently of each other. For example, The upper end of the first upper punch 31 may be connected to the first upper plate, and the upper end of the second upper punch 32 may be connected to the second upper plate. The first upper plate and the second upper plate move along the first direction D1 by different drive mechanisms. Even if the first upper punch 31 and the second upper punch 32 move independently of each other, it is preferable that the compression by the first upper punch 31 and the compression by the second upper punch 32 be performed simultaneously. Simultaneous compression makes it easier to perform uniform compression of the powder 7P in the first cavity 73 and the second cavity 74.

[0041] ≪Lower punch≫ The lower punch 4 is inserted into the lower part of the hollow section 20. If the hollow section 20 is divided into multiple segments 7 by the first core 5, which will be described later, multiple lower punches 4 are provided corresponding to the number of segments 7. In this example, the lower punch 4 comprises a first lower punch 41 and a second lower punch 42, corresponding to the first segment 71 and the second segment 72. The first upper punch 31 and the first lower punch 41 are paired. The second upper punch 32 and the second lower punch 42 are paired. If the hollow section 20 is not divided, there is one lower punch 4.

[0042] Each of the first lower punch 41 and the second lower punch 42 is a columnar or cylindrical member. In this example, each of the first lower punch 41 and the second lower punch 42 is a cylindrical member into which a part of the second core 6, described later, is inserted. The outer shape of the end faces of each of the first lower punch 41 and the second lower punch 42 corresponds to the outer shape of the second end face 12 of the powder molded body 10 that is compression molded. The second end face 12 is the face facing the first end face 11 of the powder molded body 10. In this example, the outer shape of the end faces of each of the first lower punch 41 and the second lower punch 42 is substantially rectangular.

[0043] When the powder 7P shown in Figures 3 and 4 is compressed, a portion of the first core 5 is inserted between the first lower punch 41 and the second lower punch 42. The first lower punch 41 and the second lower punch 42 are positioned with a slidable gap between them, allowing a portion of the first core 5 to move freely. In this example, the first core 5 is inserted into the hollow section 20 from the same direction as the lower punch 4. Therefore, in this example, the first core 5 is always positioned between the first lower punch 41 and the second lower punch 42. In other words, the first lower punch 41 and the second lower punch 42 in this example slidably sandwich the first core 5.

[0044] In this example, the first lower punch 41 and the second lower punch 42 are each provided with a through hole 44. A portion of the second core 6, described later, is slidably inserted into the through hole 44. In this example, the second core 6 is inserted into the hollow portion 20 from the same direction as the lower punch 4. Therefore, in this example, the second core 6 is always located inside the through holes 44 of the first lower punch 41 and the second lower punch 42.

[0045] The lower punch 4 is normally fixed. The die 2, upper punch 3, first core 5, and second core 6 move relative to the lower punch 4 along the first direction D1. In this example, the lower ends of the first lower punch 41 and the second lower punch 42 are connected to a base plate 47. The base plate 47 is immovable. The second core 6 slides through the base plate 47.

[0046] ≪First Core≫ The first core 5 is a columnar member inserted into the hollow section 20 along the first direction D1, as shown in Figures 2 and 3. In this example, the first core 5 is inserted into the hollow section 20 from the same direction as the lower punch 4. In other words, the first core 5 is inserted into the hollow section 20 from below the die 2.

[0047] In this example, the first core 5 is inserted into the hollow section 20 so as to divide the hollow section 20 into multiple segments 7. The multiple segments 7 are arranged in parallel in the second direction D2. In this example, the first core 5 is positioned to divide the hollow section 20 into two segments 7: a first segment 71 and a second segment 72. Cavities are formed corresponding to the number of segments 7, in this example, a first cavity 73 and a second cavity 74.

[0048] The shape of the first core 5 is determined in accordance with the shape and number of powder molded bodies 10 to be compression molded. In this example, the shape of the first core 5 is substantially rectangular. The substantially rectangular shape includes a range that can be considered substantially rectangular, including shapes with chamfered corners or shapes with rounded corners. As shown in Figure 5, the first core 5 in this example has a side surface 51 facing the first segment 71, a side surface 52 facing the second segment 72, and sliding surfaces 53, 53 facing the die 2, and further has an upper end surface 54 as shown in Figures 1 to 4. As shown in Figure 5, the first core 5 in this example has a substantially rectangular cross-sectional shape in which the length in the third direction D3 is longer than the length in the second direction D2.

[0049] The first core 5, as shown in Figures 1 to 4, includes protrusions 55 provided on its sides 51 and 52. The protrusions 55 project from the sides 51 and 52 in a direction intersecting the first direction D1. The protrusions 55 also project in the second direction D2. The protrusions 55 are provided on the sides 51 and 52 midway along the first direction D1. The shape of the protrusions 55 is not limited. For example, the protrusions 55 have a curved, bulging cross-sectional shape. More specifically, the protrusions 55 in this example are columnar pieces having an arc-shaped cross-sectional shape enclosed by a circular arc and a chord.

[0050] The protrusion 55 provides an undercut portion 15 to the compression-molded powder body 10. The undercut portion 15 has an undercut shape. The undercut shape is a concave shape that is recessed in a direction intersecting the first direction D1.

[0051] In this example, the projection 55 is provided to protrude in the second direction D2 and extend in the third direction D3. The projection 55 in this example has an arc-shaped cross-section and is a columnar piece extending along the third direction D3. The projection 55 may also be provided to extend at an inclination in a direction intersecting the third direction D3. In this example, the shape of the projection 55 provided on the side surface 51 and the shape of the projection 55 provided on the side surface 52 are the same. In this example, the size of the projection 55 provided on the side surface 51 and the size of the projection 55 provided on the side surface 52 are the same. In this example, the projection 55 provided on the side surface 51 and the projection 55 provided on the side surface 52 are provided symmetrically. If the projection 55 provided on the side surface 51 and the projection 55 provided on the side surface 52 are the same shape, size, and arrangement, then multiple powder molded bodies 10 having the same undercut portion 15 can be manufactured simultaneously. If the protrusions 55 on side surface 51 and the protrusions 55 on side surface 52 are the same shape, size, and arrangement, then excessive stress is less likely to act on the first core 5. This is because, when the powder 7P shown in Figures 3 and 4 is compressed, the stress acting on the first core 5 acts substantially uniformly on sides 51 and 52. The protrusions 55 on side surface 51 and the protrusions 55 on side surface 52 do not need to be exactly the same shape and size.

[0052] At least one projection 55 is provided on each side surface 51, 52. As in this example, one projection 55 may be provided on each side surface 51, 52. Multiple projections 55 may be provided on each side surface 51, 52, such as being divided in a first direction D1 or a third direction D3.

[0053] In this example, the first segment 71 and the second segment 72 are symmetrical with respect to the first core 5. In this example, the shape of the first segment 71 and the shape of the second segment 72 are the same. In this example, the size of the first segment 71 and the size of the second segment 72 are the same. The orientation of the first segment 71 and the orientation of the second segment 72 may be different. In this example, the orientation of the first segment 71 and the orientation of the second segment 72 are symmetrical with respect to the first core 5.

[0054] As shown in Figure 2, when the first lower punch 41 is placed in the first segment 71, a first cavity 73 is formed in the first segment 71. When the second lower punch 42 is placed in the second segment 72, a second cavity 74 is formed in the second segment 72. In this example, a second core 6 is further placed in each of the first segment 71 and the second segment 72. In this example, the first cavity 73 and the second cavity 74 are rectangular tubular spaces. In this example, the first cavity 73 and the second cavity 74 have the same shape. In this example, the shapes of the first cavity 73 and the second cavity 74 are cylindrical. The powder molding apparatus 1 in this example can simultaneously mold two powder molding bodies 10 of the same shape and size.

[0055] Multiple segments 7 may include segments 7 of different shapes. For example, the shape of the first segment 71 may be different from the shape of the second segment 72. Multiple segments 7 may include segments 7 of different sizes. For example, the size of the first segment 71 may be different from the size of the second segment 72.

[0056] The first core 5 may be inserted into the hollow section 20 so as to divide the hollow section 20 into three or more segments 7. The three or more segments 7 may be arranged in parallel in the second direction D2. For example, if two first cores 5, as shown in Figure 1, are arranged in parallel in the second direction D2, the hollow section 20 is divided into three segments 7, and three powder molded bodies 10 are manufactured. In this case, as an example, the two powder molded bodies 10 manufactured from the segments 7 on both sides have one undercut 15 as shown in Figure 7, while the powder molded body 10 manufactured from the middle segment 7 has a total of two undercuts 15, one on each of the opposing sides. Alternatively, two first cores 5 with different numbers of protrusions 55 may be arranged in parallel in the second direction D2. One of the two first cores 5 may have protrusions 55 on both the side 51 and side 52, as shown in Figure 1, while the other first core 5 may have protrusions 55 only on the side 52. When two first cores 5 with different numbers of protrusions 55 are placed in parallel in the second direction D2, three powder molded bodies 10, each having one undercut portion 15, are manufactured as shown in Figure 7.

[0057] Three or more segments 7 may be arranged in parallel around the central axis of the hollow section 20. For example, if the hollow section 20 has a square cross-section, and the first core 5 is a cross-shaped columnar member, the hollow section 20 is divided into four segments 7, and four powder molded bodies 10 are manufactured.

[0058] The hollow portion 20 does not necessarily have to be divided. For example, if the hollow portion 20 has a rectangular cross-section, and the first core 5 is inserted unevenly to one side of the hollow portion 20, a segment 7 is formed in the area of ​​the hollow portion 20 where the first core 5 is not inserted. A single cavity is formed in the hollow portion 20.

[0059] The first core 5 moves along the first direction D1 by a drive mechanism 8, which will be described later. The drive mechanism 8 includes a cylinder 80. For example, the lower end of the first core 5 is connected to the lower plate 57, and the lower end of the cylinder 80 is in contact with the lower plate 57. The lower plate 57 is pushed down by the cylinder 80. As the lower plate 57 moves along the first direction D1 by the cylinder 80, the first core 5 moves along the first direction D1 in conjunction with the lower plate 57. The movement of the first core 5 will be described in detail. The lower punch 4 and the second core 6 slide freely through the lower plate 57.

[0060] The upper end surface 54 of the first core 5 is not in contact with any other components of the powder molding apparatus 1. Therefore, the upper end surface 54 of the first core is not in contact with the lower end surface of the upper punch 3. If the upper end surface 54 of the first core 5 and the lower end surface of the upper punch 3 are not in contact, the first core 5 is not affected by the movement of the upper punch 3. If the upper end surface 54 of the first core 5 and the lower end surface of the upper punch 3 are not in contact, the upper end surface 54 of the first core 5 will not wear down. The upper end surface 54 of the first core 5 is not in contact with the lower end surface of the upper punch 3 throughout the entire process, from filling the cavities, in this example, the first cavity 73 and the second cavity 74, with powder 7P to removing the compression-molded powder molding 10.

[0061] ≪Second Core≫ The second core 6 is a columnar member inserted into the hollow section 20 in parallel with the first core 5, as shown in Figures 1 to 4. The second core 6 is inserted into the hollow section 20 from the same direction as the lower punch 4. In other words, the second core 6 is inserted into the hollow section 20 from below the die 2. The length of the second core 6 along the first direction D1 is longer than the length of the lower punch 4 along the first direction D1. The second core 6 has a structure that allows it to be fitted into the hollow section 20 together with the lower punch 4 and the first core 5 from the same direction as the lower punch 4. If the hollow section 20 is divided into multiple segments 7 by the first core 5, multiple second cores 6 are provided corresponding to the number of segments 7. The second core 6 is inserted into the through holes 44 of the first lower punch 41 and the second lower punch 42, respectively. The second core 6 forms through holes 16 in the powder molded body 10 that is compression molded. The shape of the second core 6 corresponds to the shape of the through holes 16. In this example, the shape of the second core 6 is cylindrical.

[0062] The two second cores 6 move along a first direction D1 by a drive mechanism (not shown). The drive mechanism includes, for example, a ram. The two second cores 6 may operate in conjunction with each other. For example, the lower ends of each of the two second cores 6 are connected to a yoke plate 67, and the yoke plate 67 is connected to a drive mechanism (not shown). As the yoke plate 67 moves along the first direction D1 by the drive mechanism, the two second cores 6 move simultaneously along the first direction D1 in conjunction with the yoke plate 67.

[0063] ≪Drive Mechanism≫ The drive mechanism 8 is a mechanism that moves the first core 5 along the first direction D1. The drive mechanism 8 includes a cylinder 80. The cylinder 80 powers the first core 5 so that it moves independently of the die 2, the upper punch 3, the lower punch 4, and the second core 6. In the cylinder 80, a piston reciprocates within a hollow cylinder by pneumatic or hydraulic power. The piston moves along the first direction D1.

[0064] The drive mechanism 8 in this example includes a lower plate 57. The upper end of the cylinder 80 is supported by the upper plate 37. The lower end of the cylinder 80 can contact the lower plate 57 by extending the piston. As shown in Figure 4, when the cylinder 80 moves downward along the first direction D1, the lower end of the cylinder 80 pushes the lower plate 57 down along the first direction D1. As the lower plate 57 moves down along the first direction D1, the first core 5 moves down along the first direction D1 in conjunction with the lower plate 57.

[0065] <Powder molded body> The powder molded body 10 produced by the powder molded body manufacturing apparatus 1 described above includes an undercut portion 15, as shown in Figure 7. The undercut portion 15 is a recessed area indented from the side surface 13. The powder molded body 10 in this example further includes a through hole 16.

[0066] <Method for manufacturing powder-molded bodies> The method for manufacturing a powder molded body according to an embodiment will be described with reference to Figures 1 to 4 and Figure 6. The method for manufacturing a powder molded body comprises a preparation step, a filling step, a molding step, and a removal step, which are performed in order.

[0067] ≪Preparation Steps≫ In the preparation step, the powder molded body manufacturing apparatus 1 described above is prepared. The shapes of the die 2, upper punch 3, lower punch 4, first core 5, and second core 6 can be appropriately selected to correspond to the shape of the powder molded body 10 to be manufactured.

[0068] ≪Filling process≫ In the filling process, powder 7P (Figure 3) is filled into the hollow section 20, into which the lower punch 4 and the first core 5 are inserted, as shown in Figure 1. As shown in Figure 2, the hollow section 20 into which the lower punch 4 and the first core 5 are inserted is a cavity, in this example a first cavity 73 and a second cavity 74. In this example, a second core 6 is also inserted into the hollow section 20. The upper end surface of the second core 6 is positioned above the upper end surface of the lower punch 4. The upper end surface 54 of the first core 5 and the upper end surface of the second core 6 are on the same plane as, for example, the upper end surface of the die 2.

[0069] ≪Molding process≫ The molding process comprises a first step of lowering the upper punch 3, a second step of lowering the cylinder 80 of the drive mechanism 8, and a third step of compressing the powder 7P with the upper punch 3 and the lower punch 4. In the molding process, when the powder 7P is compressed with the upper punch 3 and the lower punch 4, the first core 5 needs to be positioned in a predetermined location. To adjust the position of the first core 5, the drive mechanism 8 moves the first core 5 to a predetermined position. In order to move the first core 5 to a predetermined position, the drive mechanism 8 lowers the first core 5.

[0070] The length of the cylinder 80 may be adjusted in advance to determine the timing of the descent of the upper punch 3 and the first core 5. In this case, as the upper punch 3 descends, the lower end of the cylinder 80, whose length has been adjusted in advance, reaches the lower plate 57, causing the lower end of the cylinder 80 to push down the lower plate 57, and the upper punch 3 and the first core 5 to descend in conjunction. The first and second steps may be performed simultaneously. For example, the cylinder 80 may be operated to lower the first core 5 while the upper punch 3 is being lowered. The second and third steps may be performed simultaneously. Furthermore, the first, second, and third steps may be performed in conjunction without a clear separation. For example, in the third step, the lower punch 4 remains stationary, while the die 2, upper punch 3, and second core 6 are lowered. In the third step, the cylinder 80 may be operated to lower the first core 5 at the timing when the powder 7P is compressed by the upper punch 3. After the powder 7P is compressed and molded by the upper punch 3 and lower punch 4, the first core 5 is not lowered.

[0071] When compressing the powder 7P, a resistive force from the powder 7P is applied below the protrusion 55 of the first core 5. By forcibly moving the first core 5 downward with the drive mechanism 8, even if a resistive force from the powder 7P is applied below the protrusion 55, the protrusion 55 is positioned appropriately during the compression of the powder 7P. Therefore, in the manufactured powder molded body 10, the position of the undercut portion 15 is set to a predetermined position with high precision. The timing of moving the first core 5 is adjusted independently of the timing of moving the other components. If the timing of moving the first core 5 can be adjusted individually, the compression of the powder 7P can be performed appropriately regardless of the shape and size of the protrusion 55 of the first core 5.

[0072] In this example, the powder 7P in the first cavity 73 is compressed by the first upper punch 31 and the first lower punch 41, and the powder 7P in the second cavity 74 is compressed by the second upper punch 32 and the second lower punch 42. In this example, two powder molded bodies 10 are molded simultaneously.

[0073] ≪Removal Process≫ In the removal process, as shown in Figure 6, the die 2, upper punch 3, and second core 6 are moved relative to the lower punch 4. Specifically, with the lower punch 4 and first core 5 fixed, the upper punch 3 is raised along the first direction D1, and the die 2 and second core 6 are lowered along the first direction D1.

[0074] The removal process positions each powder molded body 10 outside the hollow portion 20 of the die 2. Once outside the hollow portion 20, each powder molded body 10 has surfaces other than the contact surface with the first core 5 exposed. Each powder molded body 10, located outside the hollow portion 20, is movable away from the first core 5. Each powder molded body 10 can be removed by detaching it from the first core 5. In this example, two powder molded bodies 10 are moved away from each other along the second direction D2. This removal process allows for easy removal of the powder molded body 10 having the undercut portion 15 shown in Figure 7 from the powder molded body manufacturing apparatus 1.

[0075] After the powder molded body 10 is removed from the powder molded body manufacturing apparatus 1, the lower plate 57 is returned to its predetermined position. The predetermined position of the lower plate 57 is the position before it is pushed down by the cylinder 80 during the molding process. Below the lower plate 57, a cylinder (not shown) is positioned to push up the lower plate 57. After the lower plate 57 is pushed down by the cylinder 80 during the molding process, it is pushed up to its predetermined position just before filling the cavity with powder 7P during the process of manufacturing the next powder molded body 10, following the removal of the powder molded body 10 from the powder molded body manufacturing apparatus 1. [Explanation of Symbols]

[0076] 1. Apparatus for manufacturing powder molded bodies 2 die, 20 hollow section, 21 inner surface 3. Upper punch, 31. First upper punch, 32. Second upper punch 34 Through hole, 37 Upper plate 4. Lower punch, 41. First lower punch, 42. Second lower punch 44 through holes, 47 base plate 5 First core, 51, 52 Side surfaces, 53 Sliding surface, 54 Upper end surface 55 Protrusion, 57 Lower plate 6. Second core, 67. Yoke plate 7 Segment, 71 First Segment, 72 Second Segment 73 First cavity, 74 Second cavity, 7P Powder 8 Drive mechanism 80 cylinders 10 Powder molded body 11 first end surface, 12 second end surface, 13 side surface 15 Undercut section, 16 Through hole D1 first direction, D2 second direction, D3 third direction

Claims

1. A die having a hollow portion penetrating in the first direction, An upper punch and a lower punch for compressing the powder placed inside the hollow section, A first core is inserted into the hollow portion from the same direction as the lower punch along the first direction, The first core is driven by a drive mechanism that moves the first core along the first direction, The first core is provided with a projection that protrudes from the side surface of the first core in a direction intersecting the first direction, The aforementioned drive mechanism is A cylinder that provides power to the first core so as to move independently of the die, the upper punch, and the lower punch, The lower plate is connected to the lower end of the first core, The upper end of the cylinder is supported by an upper plate connected to the upper end of the upper punch. The lower end of the cylinder is in contact with the lower plate, The cylinder moves the lower plate along the first direction. A manufacturing apparatus for powder-molded products.

2. The apparatus for manufacturing a powder molded body according to claim 1, wherein the upper end surface of the first core is in non-contact with the lower end surface of the upper punch.

3. The apparatus for manufacturing a powder molded article according to claim 1 or 2, wherein the first core is inserted into the hollow portion such that the hollow portion is divided into a plurality of segments arranged in parallel in a direction perpendicular to the first direction.

4. The apparatus for manufacturing a powder molded article according to claim 1 or claim 2, further comprising a second core inserted in parallel with the first core into the hollow portion.

5. A step of preparing a manufacturing apparatus for a powder molded body according to claim 1 or claim 2, A step of filling the hollow portion into which the first core and the lower punch are inserted with the powder, A step of compressing the powder with the upper punch and the lower punch to form a powder molded body, The process includes moving the die and the upper punch relative to the lower punch to remove the powder molded body, In the process of forming the powder molded body, the first core is moved to a predetermined position by the drive mechanism. A method for manufacturing a powder-molded body.

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