JP2009018318A - Powder forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily adjust the difference in deflection in the axial direction of punch split bodies of a powder forming apparatus having a plurality of lower punches and upper punches without disassembly of a die device or replacement of components. <P>SOLUTION: A punch adapter 6 which can be deflected under the forming pressure is provided, and a lower side of a lower first punch 4<SB>-1</SB>is supported by the punch adapter. An adapter supporter 7a (a ram 14c) capable of adjusting the distance from the punch adapter 6 is installed below the punch adapter 6 through the external operation. The deflection in the axial direction of the punch adapter 6 is adjusted by the adapter supporter 7a to absorb the difference in deflection in the axial direction between the lower first punch 4<SB>-1</SB>and a lower second punch 4<SB>-2</SB>by the deflection of the punch adapter 6. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  In the present invention, there are a plurality of at least one of a lower punch and an upper punch that are arranged to face each other, and the axial deflection due to the molding pressure of each divided body due to the difference in length and thickness of the plurality of punches (hereinafter referred to as divided bodies) More particularly, the present invention relates to a powder molding apparatus provided with a function of adjusting the difference in the amount of axial deflection.

  The sintered part is manufactured by compression-molding powder with a powder molding apparatus and then sintering the obtained green compact. Molding of the green compact by the powder molding apparatus is performed using a mold apparatus (die set) including a die, an upper punch, and a lower punch as minimum elements. As the mold apparatus, one having a plurality of lower punches and upper punches is used depending on the shape of the green compact. A punch composed of a combination of a plurality of punches has an axial deflection due to the molding pressure of each divided body due to differences in the length and thickness of each divided body (hereinafter referred to simply as the amount of deflection, which is all referred to as an axial deflection). Difference). For the upper punch, there is little problem even if there is a difference in the amount of bending of each divided body, but for the lower punch, if the difference in the amount of bending of the divided body exceeds the allowable limit, the pressure after completion of powder compression will be reduced. At the time of punching, an unreasonable force is applied to the green compact in the cavity due to the difference in the elastic restoring amount of the divided bodies, which becomes a major factor causing cracks in the formed green compact.

As a countermeasure, a method of calculating the bending amount of the punch and jigs holding the punch at the time of design and minimizing the difference in the bending amount of each molded part (divided body) is adopted. A supporting jig may be provided on the supporting floor surface to absorb a difference in the amount of bending. The bending jig is composed of a bending plate or the like, and compensates for the insufficient bending amount of the divided body having the smaller bending amount by the bending of the bending jig.

Further, a countermeasure as disclosed in Patent Document 1 below is also considered. Patent Document 1
Devised the structure of the mold, and the first lower punch and the second lower punch at the time of depressurization by providing a step on the outer peripheral molding surface of the second lower punch arranged inside the first lower punch The stress applied to the green compact (molded product) due to the difference in restoration amount is dispersed at a plurality of locations to suppress the occurrence of cracks.
Japanese Patent Laid-Open No. 2001-30098

  Mold deflection is calculated based on the density of each molded part of the green compact, but the density at the time of design and mass production is often different. It is not easy to fit in. In general, it is said that cracks occur in the green compact when the difference in the amount of deflection of the divided body is about 5/100. Since the calculation of the amount of deflection is inadequate, the difference in the amount of deflection of each molded part has an allowable range. In some cases, the green compact may crack.

  Moreover, it is not easy to determine the bending absorbability of a jig | tool with the method of absorbing the difference of the bending amount of a division body using a bending jig | tool. It is unlikely that the optimal bending jig will be determined by a single design, and an appropriate bending jig is obtained by repeating the design, analysis, prototyping, assembly to the mold equipment, and removal many times. is there. Such a cumbersome method is unavoidable because the relationship between the amount of deflection of the bending jig and the amount of return and the necessary adjustment amount are not quantified, and there is no clear design standard. .

In addition, in the adjustment using the bending jig, when the jig breaks, it is necessary to disassemble the mold device and replace the broken jig. The problem of rate drop also occurs.

  In order to solve the above-described problems, an object of the present invention is to make it easy to adjust the difference in the amount of flexure of a divided body without disassembling the mold apparatus or replacing parts.

  In order to solve the above-mentioned problems, in the present invention, the following elements are included in a powder molding apparatus that fills a cavity formed in a die with a powder, and compresses the filled powder with an upper punch and a lower punch arranged opposite to each other. Added. The powder molding apparatus according to the present invention includes a plurality of at least one of an upper punch and a lower punch. At least one punch (divided body) of the plurality of upper punches and lower punches is supported by a punch adapter provided on the upper punch upper surface and / or the lower punch lower surface, and further, the upper portion of the punch adapter supporting the upper punch or An adapter support that adjusts the distance between the punch adapter and the punch adapter by an external operation was installed below the punch adapter that supported the lower punch. Use a punch adapter that is allowed to bend at the molding pressure, that is, designed so that the punch support surface is displaced in the axial direction by bending at the molding pressure. Control with an adapter support that adjusts the distance between

  The powder molding apparatus according to the present invention may include a plurality of punches (divided bodies) each having a different amount of axial deflection due to molding pressure. The difference in the amount of deflection of the divided body is particularly problematic in a powder molding apparatus having a plurality of lower punches (consisting of a plurality of divided bodies). In the apparatus, at least one punch (divided body) among a plurality of lower punches is supported by a punch adapter provided on the lower surface of the lower punch, and control means for adjusting the amount of deflection at the lower part of the punch adapter, The adapter support for adjusting the distance from the punch adapter is provided.

  When there is a possibility that the deflection amount difference of each lower punch divided body of the apparatus may exceed the allowable limit, a plurality of lower punch divided bodies are individually supported by punch adapters provided corresponding to each divided body, and each punch adapter is supported. It is preferable to provide an adapter supporter that serves as a means for controlling the amount of deflection at the lower part.

  The adapter support tool is preferably a screw jack ram that can be operated from the outside. It is simple and excellent in operability, but it can be inserted from the side between the punch adapter and the base plate that supports the punch adapter. A wedge member may be interposed, and the wedge member may be used as an adapter support.

  In the powder molding apparatus according to the present invention, at least one of the divided body of the lower punch and the upper punch is supported by the punch adapter. The punch adapter has a constant rigidity, and when subjected to the molding pressure, tries to bend by an amount corresponding to the molding pressure. However, the actual deflection stops at the restriction position by the adapter support (deflection amount control means). The adapter support tool can adjust the distance from the punch adapter, thereby adjusting the deflection amount of the punch supported by the punch adapter within the range of 0 to the maximum deflection amount of the punch adapter. It is possible to reduce the difference in the amount of bending to the point where cracking of the green compact is reliably prevented.

  To adjust the bending amount of the punch adapter, it is only necessary to move the adapter support tool in the axial direction and change the distance between the punch adapter and the position of the adapter support tool can be adjusted by an external operation. In addition, it is not necessary to replace the parts of the mold apparatus, and the adjustment work can be easily performed.

  In addition, since the relationship between the amount of bending of the punch adapter and the cracks that occur in the green compact can be understood from the distance adjustment amount of the adapter support, re-adjustment that is required when the adapter support is replaced is also possible with the previous adjustment work. It becomes easy to do based on the obtained data.

  In addition, both the punch adapter and the adapter support (deflection amount control means) for adjusting the deflection amount of the adapter may have a simple structure, and the complexity of the apparatus and the increase in the apparatus cost can be suppressed.

  Embodiments of the powder molding apparatus of the present invention will be described below with reference to FIGS. 1 to 5 of the accompanying drawings. The powder forming apparatus 1 shown in FIG. 6 has a compact shown in FIG. 6, that is, a shaft hole 22 having a shaft hole 22 at the center of the main body portion 21 and a boss portion 23 protruding to the other end side of the main body portion 21. The green compact 20 is obtained.

An outline of the powder molding apparatus 1 is shown in FIG. The molding apparatus 1 includes a die 2 that molds the outer peripheral surface of the green compact body portion at the hole surface of the molding hole 2a, and press-molds one end surface of the green compact body portion into the die molding hole 2a. on the punch 3, lower 1 punch 4 _-1 and end surface of the boss portion formed in the green compact pressing compaction processing the end surface of the main body portion of the stand to the green compact in a forming hole 2a of punch adapter characterizing (the two parties divided body referred to in the present invention) under 2 2's punch 4 _-2 and lower punch 4 consisting of a core rod 5 for molding the shaft hole in the center of the green compact, the present invention is 6 and a die device (die set) in which a deflection amount control means 7 for controlling the deflection amount of the punch adapter is combined. The mold apparatus fills a cavity 8 formed between the die 2, the lower punch 4 and the core rod 5 with powder, and compresses the powder with upper and lower punches to obtain a desired green compact.

The die 2 is attached to the die plate 9. The die plate 9 is connected to a lower ram (not shown) or the like of the press machine, and the die 2 held on the die plate 9 is lowered halfway when the powder is compressed, and then the compression is completed. Later, the green compact is pulled down from the cavity 8 until it is discharged. The upper punch 3 is driven by an upper punch plate 10 driven by an upper ram (not shown) of the press, and the lower 2 punch _4-2 is driven by a drive mechanism (not shown) separate from the die drive mechanism. respectively attached to the lower punch plate 11 to be lowered by further below 1 punch 4 _-1 on punch adapter 6, the punch adapter 6 and the deflection means 7 are respectively attached to the base plate 12.

Under 2 punch 4 _-2 long as shown in FIG. 2, are inserted inside the lower 1 punch 4 _-1, its length than the length of the lower 1 punch 4 _-1. Further, an outer diameter smaller than the outer diameter of the lower 1 punch 4 _-1, therefore, the amount of deflection due to molding pressure is larger than the lower 2 punch 4 towards _-2 below 1 punch 4 _-1. To pay the deflection amount difference within the allowable range, supplementing the deflection amount shortage under 1 punch 4 _-1 using a punch adapter 6.

The punch adapter 6 has a punch support surface 6a, and the lower punch _4-1 is supported by the punch support surface 6a. This punch adapter 6 is designed so that the material, thickness, distance from the center to the support point, etc. are appropriately set to bend with the molding pressure, and the outer peripheral portion is supported and supported by the spacer 13 on the base plate 12. Installed. The portion corresponding to the punch support surface 6a of the punch adapter 6 (punch supporting portion) has become a non-supporting state, the molding pressure is applied down one punch 4 _-1, the non-supported part at the load at that time The punch support surface 6a hangs by bending, and the amount of sag at that time is added to the amount of bending of the lower 1 punch _4-1 , thereby adjusting the amount of bending between the lower 1 and lower 2 punches.

The deflection amount control means 7 is installed below the punch adapter 6. The deflection amount control means 7 has an adapter support 7 a that can adjust the distance from the punch adapter 6.

  The exemplified deflection amount control means 7 is constituted by the screw jack 14 shown in FIG. The screw jack 14 includes a worm gear composed of a worm 14a and a worm wheel 14b that can be rotated from the outside, and a cylindrical ram 14c to which the worm wheel 14b of the worm gear is attached. A trapezoidal male screw 14d is formed on the outer periphery of the ram 14c, and the trapezoidal male screw 14d is screwed to a female screw 14e provided on the base plate 12.

The ram 14c of the screw jack 14 is used as the adapter support 7a. When the worm 14a is operated and rotated from the outside, a thrust is generated in the ram 14c, and the ram 14c moves up and down. By controlling the amount of lift, the space between the adapter support 7a (ram 14c) and the punch adapter 6 is increased. The distance is adjusted.
As shown in FIG. 3, the punch adapter 6 that has received the molding pressure is supported and supported by the adapter support 7a (ram 14c) waiting downward, and the bending stops at that position. Therefore, the deflection amount of the punch adapter 6 can be adjusted by changing the distance from the adapter support 7a to the punch adapter 6 (gap g in FIG. 2).

It has been empirically known that the adjustment of the bending of each divided body of the lower punch 4 should be ensured by an adjustment amount of about 0 to 1 mm. Powder molding apparatus 1 of the present invention, by setting the maximum amount of deflection due to a molding pressure of the punch adapter 6, for example 1 mm, the difference in deflection amount of the lower 1 punch 4 _-1 and lower two punch 4 _-2 0~1mm range It is possible to prevent the occurrence of cracks in the green compact due to the difference in deflection amount between the lower and lower punches by a simple operation of adjusting the axial position of the adapter support. Become.

  Further, when the deflection amount control means 7 is provided, the relationship between the deflection amount of the punch adapter 6 and the crack generated in the green compact can be understood. It becomes easy to do based on the data obtained in the work.

  The above description has been given by taking as an example the case where there are a plurality of lower punches, but there is also a powder molding apparatus in which a plurality of upper punches or a plurality of lower punches and upper punches are provided. If the upper punch also has a large difference in the amount of bending due to the molding pressure of the plurality of divided bodies, it is conceivable that cracks and the like occur in the green compact, although not as much as the lower punch. Depressurization after completion of powder compression is usually done by a method of loosening the pressure applied by the upper punch. However, a situation occurs in which the pressure is released prior to the other part of the divided body, and the load acts on a part of the green compact. The situation does not last long, but it is not preferable. Therefore, the present invention demonstrates its effectiveness even when applied to the upper punch. When the present invention is applied to an upper punch, the upper surface of the upper punch is supported by a punch adapter, and an adapter support (which may have the same structure as described above) is installed on the upper portion of the punch adapter.

  Depending on the shape of the green compact, three or more lower punches and upper punches are provided. The powder forming apparatus having the lower punches having the number of divided bodies of 3 is provided with two lower 2 punches referred to in the present invention. When the two lower 2 punches generate a deflection amount exceeding the allowable limit with respect to the lower 1 punch, the two lower 2 punches are individually supported by punch adapters provided corresponding to the lower 2 punches. Each punch adapter is provided with a deflection amount control means 7. The same applies to an apparatus having two or more lower two punches or an apparatus having two or more upper punches.

  4 and 5 show another embodiment of the deflection amount control means. This deflection amount control means 7 has an adjusting mechanism 15 having a wedge member 15a that can be inserted from the side between the punch adapter 6 and the base plate 12, and uses the wedge member 15a of this mechanism as an adapter support. A taper surface 15b corresponding to the inclined upper surface of the wedge member 15a is provided on the lower surface of the punch adapter 6 (the upper surface of the punch adapter 6 is applied to the upper punch). It is received and supported by the wedge member 15a.

  The wedge member 15a is screwed with an adjustment bolt 15d supported by a support member 15c so as to be rotatable at a fixed position. By rotating the adjustment bolt 15d, the wedge member 15a moves on the base plate 12 in a plan view of the mold apparatus. Slide in the radial direction with respect to the axis. The slide changes the height position of the upper surface of the wedge member 15a, and the distance between the punch adapter 6 and the wedge member 15a (that is, the amount of deflection of the punch adapter 6) is adjusted.

  The deflection amount control means 7 shown in FIGS. 4 and 5 needs to be provided with a plurality of wedge members 15a for performing individual slide adjustments. Therefore, adjustment work increases compared to the deflection amount control means shown in FIG. Even in such a case, the deflection amount of the punch adapter 6 can be controlled within a predetermined range without disassembling the mold device or replacing the parts.

Sectional drawing which shows the outline | summary of the principal part of the powder molding apparatus of this invention Partially broken front view showing a part of the apparatus of FIG. The figure which shows the state which the punch adapter of FIG. 2 bent to the position received by an adapter support tool with molding pressure The top view which shows the outline | summary of the other example of bending amount control means Sectional drawing along the XX line of FIG. 1 is a perspective view of a green compact formed by the apparatus of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Powder shaping | molding apparatus 2 Die 2a Molding hole 3 Upper punch 4 Lower punch 4 _-1 Lower 1 punch 4 _-2 Lower 2 punch 5 Core rod 6 Punch adapter 6a Punch support surface 7 Deflection amount control means 7a Adapter support tool 8 Cavity 9 Die plate DESCRIPTION OF SYMBOLS 10 Upper punch plate 11 Lower punch plate 12 Base plate 13 Spacer 14 Screw jack 14a Worm 14b Worm wheel 14c Ram 14d Trapezoid male screw 14e Female screw 15 Adjustment mechanism 15a Wedge member 15b Tapered surface 15c Support member 15d Adjustment bolt

Claims (4)

A powder molding apparatus for filling a cavity (8) formed in a die (2) with powder, and compressing the filled powder with an upper punch (3) and a lower punch (4) arranged opposite to each other,
A plurality of at least one of the upper punch (3) and the lower punch (4) is provided, and at least one of the punches is supported by a punch adapter (6) provided on the upper punch upper surface and / or the lower punch lower surface. Adjust the distance between the punch adapter (6) supporting the punch (3) or the lower part of the punch adapter (6) supporting the lower punch (4) with the punch adapter (6) from the outside. A powder molding apparatus characterized in that an adapter support (7a) is installed. A powder molding apparatus for filling a cavity (8) formed in a die (2) with powder, and compressing the filled powder with an upper punch (3) and a plurality of lower punches (4) arranged opposite to each other. ,
At least one punch among the plurality of lower punches (4) is supported by a punch adapter (6) provided on the lower surface of the lower punch, and further, the punch adapter (6) is operated to the punch adapter (6) by an external operation. (6) The powder shaping | molding apparatus characterized by installing the adapter support tool (7a) which adjusts the distance between.   A plurality of lower punches (4) each having a different amount of axial deflection due to molding pressure are provided, at least one lower punch is supported by the punch adapter (6), and the adapter support ( The powder molding apparatus according to claim 2, wherein a control means (7) is provided for adjusting the amount of axial deflection of the punch adapter (6) by installing 7a). The adapter support (7a) is composed of a ram (14c) of a screw jack (14) operable from the outside, and the adjustment of the distance between the punch adapter (6) and the adapter support (7a) The powder forming apparatus according to any one of claims 1 to 3, wherein the powder forming apparatus is performed by raising and lowering 14c).

Images