JP2012245563A - Powder molding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To compatibly increase the strength of a powder molding device and to enhance the deflection adjusting capacity thereof with a simple constitution, and to control generation of cracks in a green compact caused by the difference in deflection in the compression molding by a forming die using the powder molding device.SOLUTION: The powder molding device is used for the compaction molding of a sintered component, and includes a die, an upper punch, a plurality of lower punches and a core. A plurality of deflection adjusting members are provided below at least one lower punch.

Description

  The present invention relates to a powder molding apparatus for use in a mold for manufacturing a sintered part having a stepped shape or an intermediate collar and compacting metallurgical powder with a plurality of lower punches.

  Sintered parts are manufactured through a molding process and a sintering process. In the molding process, the green compact is manufactured by compressing the metallurgical powder using a molding press. The green compact is conveyed to a sintering furnace and sintered to produce a sintered body. The molding press is provided with a molding die including a molding die, an upper punch, a core, and a lower punch, and the metallurgical powder is supplied to a molding hole formed by the die and the lower punch. . The lower punch may be constituted by a plurality of lower punches in accordance with the shape of the sintered part. In general, when a plurality of lower punches are provided, the lower overall punch is shorter in the axial direction.

In general, the pressure during molding of the green compact is about 5 to 10 ton / cm ² , and a very large pressure is applied to the mold. The lower punch is deflected by pressure. Due to the difference in the total length and the difference in the thickness of the mold, a difference occurs in the amount of bending due to the pressure in the plurality of lower punches. When compression of the metallurgical powder is completed and the green compact is extracted, the pressure from above is released, so each bent lower punch tries to return to its original position. When the difference in the amount of deflection is large, the difference in the return amount of each lower punch also increases in proportion, and an excessive force is applied to the extracted green compact, which may cause cracks in the green compact.

  As a countermeasure, a method of calculating the deflection amount of the lower punch and the jigs holding the lower punch at the time of designing the die and minimizing the difference in the deflection amount of each lower punch is taken. In some cases, as shown in FIG. 9, the deflection adjusting member disclosed in Patent Document 1 may be installed on the lower punch support surface. The deflection adjusting member is composed of a deflection plate or the like, and is installed below the lower punch with a small deflection amount, and the deflection amount of the lower punch is increased by the deflection of the deflection adjusting member.

  Patent Document 2 discloses a powder molding apparatus that can easily adjust the bending amount of the lower punch without disassembling the mold apparatus or replacing parts. This powder molding apparatus has an adapter support that adjusts the distance from the lower punch adapter by an external operation at the lower part of the lower punch adapter that supports the lower punch, and by adjusting the distance, It is possible to adjust the amount of deflection.

Japanese Utility Model Publication No. 62-41498 JP 2009-18318 A

  However, in the deflection adjusting member disclosed in Patent Document 1, the deflection plate has high rigidity and the amount of deflection cannot be adjusted appropriately. May occur. Further, the powder molding apparatus disclosed in Patent Document 2 has a problem that the adapter support is large and cannot be installed in a compact powder molding apparatus.

  Therefore, the present invention achieves both strength and improvement of the deflection adjustment capability with a simple configuration, and in the compacting by the powder molding apparatus using this deflection adjusting member, the occurrence of cracks due to the difference in the amount of deflection in the compact. It is an object to suppress this.

  In order to solve the above problems, in the present invention, a powder molding apparatus used for compacting a sintered part and including a die, an upper punch, a plurality of lower punches, and a core, wherein at least one of the lower punches A powder molding apparatus comprising a plurality of deflection adjusting members below the first lower punch.

  The powder molding apparatus according to the present invention includes a die, an upper punch, a plurality of lower punches, and a core, and includes a plurality of deflection adjusting members below the first lower punch, which is at least one of the lower punches. By having a plurality of deflection adjusting members, it is possible to make it easy to adjust the amount of bending and to prevent the strength of the deflection adjusting members from being lowered.

  Of the deflection adjusting members, the first deflection adjusting member which is at least one of the deflection adjusting members not in contact with the first lower punch has a central hole through which the core or another lower punch passes. A first inclined surface having a concentric taper shape with respect to the center of the center hole of the first deflection adjusting member, on one of upper and lower surfaces of the first deflection adjusting member. It is preferable.

  The first deflection adjusting member is a plate-like member having a center hole through which the core or another lower punch passes, and is concentric with a tapered shape with respect to the center of the center hole of the first deflection adjusting member. If the first inclined surface forming the above is provided on one of the upper and lower surfaces of the second deflection adjusting member, the first deflection adjusting member is easily bent regardless of the direction, and the deflection adjustment is facilitated.

  It is preferable that the other surface of the first deflection adjusting member has a second inclined surface that is a concave portion when the first inclined surface is a convex portion and a convex portion when the first inclined surface is a concave portion.

  If the first inclined surface has a second inclined surface that is a concave portion when the first inclined surface is a convex portion and a convex portion when the first inclined surface is a concave portion, the other surface of the first deflection adjusting member is It becomes easier to bend and adjust the bend.

  The second deflection adjusting member, which is a deflection adjusting member in contact with the first lower punch, is a plate-like member having a central hole through which the core or another lower punch passes, and upper and lower surfaces of the second deflection adjusting member. Preferably, the second deflection adjusting member does not have an inclined surface that becomes a concave portion or a convex portion that has a concentric taper shape with respect to the center of the center hole.

  The second deflection adjusting member that receives pressure from the first lower punch needs strength. When the upper surface and the lower surface of the second deflection adjusting member are surfaces that do not have an inclined surface that becomes a concave portion or a convex portion, the pressure from the lower punch can be evenly received, and the second deflection due to the pressure. Damage to the adjustment member can be prevented.

  It is preferable that the first lower punch is attached to the lower punch holder by a cylindrical lower punch press having an inner collar, and the first deflection adjusting member is installed inside the cylindrical portion of the lower punch press.

  When the first deflection adjusting member is installed on the inner side of the cylindrical portion of the lower punch presser, the deflection adjusting member is more easily bent, and the deflection can be easily adjusted.

  The powder molding apparatus according to the present invention has a simple configuration and achieves both improvement in strength and deflection adjustment capability. In compression molding with a molding die using this jig, cracks due to the difference in deflection amount in the green compact are caused. Occurrence can be suppressed.

It is sectional drawing explaining one Embodiment of the powder shaping | molding apparatus of this invention. It is an enlarged view of the lower punch lower part of the embodiment. It is sectional drawing of the 1st bending adjustment member of the embodiment. It is a bottom view of the 1st bending adjustment member of the embodiment. It is sectional drawing of the 2nd bending adjustment member of the embodiment. It is a bottom view of the 2nd bending adjustment member of the embodiment. It is a perspective view of the lower surface of the sintered component manufactured by the same embodiment. It is sectional drawing at the time of the powder compression of the embodiment. It is an enlarged view of the lower punch lower part of the conventional powder molding apparatus.

Embodiments of the present invention will be described below with reference to the drawings.
The powder molding apparatus of the present invention is used for manufacturing a sintered part having a step or a protrusion on its surface, and is for compressing metallurgical powder filled in a molding hole to manufacture a green compact. The green compact is then sintered and sized and machined according to product specifications. The target sintered parts are automotive parts. Hereinafter, the structure of the mold and the molding process will be described.

[Mold structure]
The embodiment of the present invention shown in FIG. 1 is a powder molding apparatus for producing a sintered part A shown in FIG. FIG. 1 shows a cross-sectional view of a powder molding apparatus. The powder molding apparatus of this embodiment includes an upper punch 1, a die 2, a first lower punch 3, a second lower punch 4, and a core 5. The upper punch 1 is attached to an upper punch plate 6 driven by an upper ram of a molding press. The die 2 is attached to a die plate 7. The first lower punch 3 is attached to the first lower punch adapter 8 by pressing the flange portion using a cylindrical lower punch presser 20 having a flange at the lower part and an inner collar at the upper part. The lower punch presser 20 is fixed to the first lower punch adapter 8 by a screw 21 that passes through the cylindrical portion. The first lower punch adapter 8 is attached to the first lower punch holder 9. The second lower punch 4 is attached to the base plate 11 via a second lower punch adapter 10.

  Between the first lower punch 3 and the first lower punch adapter 8, a first deflection adjusting member 12 and a second deflection adjusting member 13 are installed in order from the bottom. FIG. 2 is an enlarged view of the lower portion of the first lower punch. The lower surface of the first deflection adjusting member 12 has a recess 14, and a gap is provided between the first deflection adjusting member 12 and the first lower punch adapter 8. The recess 14 is constituted by a first inclined surface 15.

  As shown in FIG. 2, the outer diameter of the first deflection adjusting member 12 is set to be equal to or smaller than the inner diameter of the lower punch presser 20. The lower punch presser 20 is fixed by a screw 21 penetrating the cylindrical portion. However, since the first deflection adjusting member 12 is installed inside the cylindrical portion, a deflection adjusting member is installed below the cylindrical portion. The first bending adjustment member 12 is very easily bent as compared with the configuration to be performed.

  FIG. 3 is a sectional view of the first deflection adjusting member 12. The first deflection adjusting member 12 has a central hole through which the second lower punch 4 passes in the center. On the lower surface of the first deflection adjusting member 12, the first inclined surface 15 is a concave portion having a concentric taper shape with respect to the center of the center hole in the bottom view of the second deflection adjusting member 13. Have On the upper surface of the first deflection adjusting member 12, there is a second inclined surface 16 serving as a convex portion having a concentric taper shape with respect to the center of the center hole. With this configuration, the first deflection adjusting member 12 is very easily bent.

  FIG. 4 is a bottom view of the first deflection adjusting member 12. The first deflection adjusting member 12 has a disk-like outer shape. The first inclined surface 15 having a downward slope toward the center of the first deflection adjusting member 12 has a conical shape. This shape makes it easy to bend regardless of the direction.

  FIG. 5 is a cross section of the second deflection adjusting member 13, and FIG. 6 is a bottom view. The first deflection adjusting member 12 has a plate shape and has a central hole through which the second lower punch 4 passes. The upper surface and the lower surface of the second deflection adjusting member 13 do not have inclined surfaces that become concave portions or convex portions that have a concentric taper shape with respect to the center of the center hole. In this embodiment, the upper surface and the lower surface of the second deflection adjusting member are both planes perpendicular to the central axis.

  FIG. 7 is a perspective view of the lower surface of the sintered part A. FIG. The sintered part A has four protrusions 17 on the lower surface. The lower surface of the projection 17 is formed by the first lower punch 3. The lower surface other than the protrusion 17 is formed by the second lower punch 4.

[Molding process]
In the molding step, as shown in FIG. 1, first, a metallurgy powder 18 is filled from a feeder box into a cavity formed by the die 2, the first lower punch 3, the second lower punch 4, and the core 5.

  Thereafter, the upper punch 1 is lowered. As shown in FIG. 8, the metallurgical powder is compressed by the cooperation of the upper punch 1, the die 2, the first lower punch 3, the second lower punch 4, and the core 5 to form a green compact 19. To do. In response to pressure from above, the first lower punch 3 and the second lower punch 4 bend. When there is no deflection adjusting member, the second lower punch 4 has a longer overall length than the first lower punch 3, and therefore the second lower punch 4 bends more than the first lower punch 3. In the embodiment of the present invention, the first deflection adjusting member 12 installed below the first lower punch 3 bends downward, and the difference in deflection amount between the first lower punch 3 and the second lower punch 4 is calculated. Can be reduced.

The sintered part A illustrated in FIG. 7 was molded using the first deflection adjusting member 12 shown in FIG. 3 and the second deflection adjusting member 13 shown in FIG. The dimensions of the sintered part A are as follows.
Outer diameter: 120mm
Thickness T: 20mm
Projection length L: 30 mm
The dimensions of the first deflection adjusting member 12 are as follows.
Thickness: 5mm
Outer diameter: 180mm
Inner diameter: 90mm
The outer diameter of the first inclined surface: 160 mm
Height of first inclined surface H1: 0.6 mm
Inner diameter of second inclined surface: 130 mm
Height H2 of the second inclined surface: 0.6 mm
The dimensions of the second deflection adjusting member 13 are as follows.
Thickness: 5mm
Outer diameter: 180mm
Inner diameter: 90mm
The materials of the first deflection adjusting member 12 and the second deflection adjusting member 13 are both nickel chrome molybdenum steel.

Comparative example

As a comparative example, a sintered part A shown in FIG. 7 was formed using a conventional deflection adjusting member 22 shown in FIG.
The dimensions of the deflection adjusting member are as follows.
Thickness: 10mm
Outer diameter: 180mm
Inner diameter: 90mm
Inclined surface height H3: 0.6 mm
The material is nickel chrome molybdenum steel.
The conventional deflection adjusting member 22 has a through hole into which a screw is inserted, and is attached to the first lower punch adapter 8 by a screw 21 together with a lower punch presser 20.

Molding was performed under molding conditions of a pressure of 6 ton / cm ² .
As a result, it was confirmed that there was no crack in the sintered part A molded in the example, and a crack occurred in the sintered part A molded in the comparative example. After 1000 pieces were formed, no defects such as sag and cracks were found in the first deflection adjusting member 12 and the second deflection adjusting member 13.

  In addition, this invention is not necessarily limited to the Example mentioned above, In the range which does not deviate from the summary of this invention, it can change suitably.

  The powder molding apparatus of the present invention is suitable for obtaining various sintered parts such as automobile sintered parts.

DESCRIPTION OF SYMBOLS 1 Upper punch 2 Die 3 1st lower punch 4 2nd lower punch 5 Core 6 Upper punch plate 7 Die plate 8 1st lower punch adapter 9 1st lower punch holder 10 2nd lower punch adapter 11 Base plate 12 1st bending adjustment Member 13 Second deflection adjusting member 14 Recess 15 First inclined surface 16 Second inclined surface 17 Protrusion 18 Metallurgical powder 19 Green compact 20 Lower punch press 21 Screw 22 Conventional deflection adjusting member A Sintered part

Claims (5)

A powder molding apparatus that is used for compacting of sintered parts and includes a die, an upper punch, a plurality of lower punches, and a core,
A powder molding apparatus comprising a plurality of deflection adjusting members below a first lower punch which is at least one of the lower punches. Of the deflection adjusting members, the first deflection adjusting member which is at least one of the deflection adjusting members not in contact with the first lower punch has a center hole through which the core or another lower punch passes. A plate-shaped member having
The upper and lower surfaces of the first deflection adjusting member have a first inclined surface having a concentric taper shape with respect to the center of the central hole of the first deflection adjusting member. Item 2. The powder molding apparatus according to Item 1.   The second surface of the first deflection adjusting member has a second inclined surface which is a concave portion when the first inclined surface is a convex portion and a convex portion when the first inclined surface is a concave portion. Powder molding equipment. The second deflection adjusting member that is a deflection adjusting member in contact with the first lower punch is a plate-like member having a center hole through which the core or another lower punch passes,
2. The upper and lower surfaces of the second deflection adjusting member do not have inclined surfaces that are concentrically tapered with respect to the center of the center hole of the second deflection adjusting member. The powder shaping | molding apparatus of any one of Claim 3.   The first lower punch is attached to a lower punch holder by a cylindrical lower punch press having an inner collar, and the first deflection adjusting member is installed inside a cylindrical portion of the lower punch press. The powder molding apparatus according to any one of claims 1 to 4.

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