JP2005034904A

JP2005034904A - Manufacturing method and sintered parts of powder compact

Info

Publication number: JP2005034904A
Application number: JP2003324093A
Authority: JP
Inventors: Toshiro Yoshihara; 敏郎吉原; Takuya Masaka; 卓也真坂
Original assignee: Kobayashi Industry Co Ltd
Current assignee: Kobayashi Industry Co Ltd
Priority date: 2003-06-26
Filing date: 2003-09-17
Publication date: 2005-02-10
Anticipated expiration: 2023-09-17
Also published as: JP4571791B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide the manufacturing method of a powder compact which consists of a packing method and a compressing method of powder suitable to a case that a powder packing layer having an uncompressed layer is compressively compacted. <P>SOLUTION: In the manufacturing method by which the packed powder is compressively compacted while a blanking pin for forming a shaft hole 2 is inserted into the compact, upper and lower powder replenishing punches 8, 10 which are operated independently of compacting punches 7, 8 are provided in a position outside the projecting region of the blanking pin, a prescribed powder packing amount which is calculated from the volume of the compact and compressibility is distributed to the packing powder layer 3 and replenishing powder layer 4 which is compressed with the powder replenishing punches 8, 10 and compressive compacting is performed while replenishing the powder of the replenishing powder layer 4 to the packing powder layer 3. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

本発明は粉末成形体の製造方法に関し、特に、非圧縮層を有したまま圧縮成形する工程により成形される粉末成形体の製造方法及び当該粉末成形体を使用した高強度の燒結部品に関する。 The present invention relates to a method for producing a powder molded body, and more particularly to a method for producing a powder molded body formed by a compression molding process with an uncompressed layer and a high-strength sintered part using the powder molded body.

粉末成形体の外周面を成形するダイと、上端面を形成する上パンチ及び下端面を形成する下パンチとにより画成されるキャビティ内に粉末を充填し、プレスを用いて上下パンチをストロークさせ所定の圧縮密度の成形体とし、該成形体を焼結して部品や工具を製造することが行われている。特開２００１−０８９８０２号には、キャビティに充填された材料粉末を上下パンチで圧縮成形した粉末成形体に軸孔を形成する方法が記載されている。図８（ａ）、（ｂ）を参照して打ち抜きピンの作動を説明する。図８（ａ）において、ダイ５の側面に打ち抜きピン１５を配設し、上下パンチ間の充填粉末層３の圧縮方向に生成するニュートラル・ラインに打ち抜きピン軸線を一致させて打ち抜きピン１５を充填粉末層３に挿入する。１６は打ち抜きピン１５が挿通する通孔である。図８（ｂ）は打ち抜きピン１５により軸孔が形成された後の状態を示す。充填粉末層３から打ち抜かれた粉体１７は通孔１６を介してダイ５に設けられた排出口から排出される。その後、打ち抜きピンを挿入した状態で、上端面からの上パンチ９の下降ストローク量と、下端面からの下パンチ７のストローク量とを同一に設定して充填された粉末を上下パンチにより圧縮して成形体とする。該成形体から打ち抜きピンを引き抜くことにより軸孔を有する粉末成形体を製造する。 Powder is filled into a cavity defined by a die for forming the outer peripheral surface of the powder molded body, an upper punch for forming the upper end surface, and a lower punch for forming the lower end surface, and the upper and lower punches are stroked using a press. A molded body having a predetermined compression density is manufactured, and the molded body is sintered to produce parts and tools. Japanese Patent Application Laid-Open No. 2001-089802 describes a method of forming a shaft hole in a powder molded body obtained by compression molding a material powder filled in a cavity with an upper and lower punch. The operation of the punching pin will be described with reference to FIGS. 8 (a) and 8 (b). In FIG. 8 (a), a punching pin 15 is disposed on the side surface of the die 5, and the punching pin 15 is filled by making the punching pin axis line coincide with the neutral line generated in the compression direction of the filling powder layer 3 between the upper and lower punches. Insert into powder layer 3. Reference numeral 16 denotes a through hole through which the punching pin 15 is inserted. FIG. 8B shows a state after the shaft hole is formed by the punching pin 15. The powder 17 punched out from the filled powder layer 3 is discharged from a discharge port provided in the die 5 through a through hole 16. After that, with the punching pin inserted, the lowering stroke amount of the upper punch 9 from the upper end surface and the stroke amount of the lower punch 7 from the lower end surface are set to be the same, and the filled powder is compressed by the upper and lower punches. To form a molded body. A powder molded body having a shaft hole is produced by pulling out the punching pin from the molded body.

上記方法においては、圧縮工程において圧縮される粉末層に打ち抜きピンという非圧縮物が存在する。かかる条件を考慮せず均一に粉末を充填して圧縮成形する場合は、図１（ａ）を参照して、圧縮時に打ち抜きピンと上下パンチとにより圧縮されるａ部と打ち抜きピンに影響されないｂ部とでは圧縮率が異なるためｂ部の密度が上がらないばかりではなく、良好な成形体が得られない。 In the above method, there is an uncompressed product called a punching pin in the powder layer compressed in the compression step. When the powder is uniformly filled and compression-molded without taking such conditions into consideration, referring to FIG. 1 (a), the part a which is compressed by the punching pin and the upper and lower punches during compression and the part b which is not affected by the punching pin And the compression ratio differs, so that not only the density of the portion b does not increase, but also a good molded article cannot be obtained.

例えば、特開平６−１９８４９７号に、同心的に嵌合された３分割の下パンチを用い、ダイ内部に充填された粉末を圧縮して下端部が段状をなす成形体を得る成形方法が開示されている。この場合、上パンチと各下パンチのダイに対する相対的な移動速度を、成形品各段部の圧縮量の比率と同一速度比に設定して制御する。かかる多段状の粉末成形体を圧縮成形する場合、各段部の圧縮率を変えることは圧縮成形中に、圧縮密度の高い段部から低い段部へ粉末の移動が起こり良好な成形体が得られない。これと同様の粉末の移動が圧縮される充填粉末層内部に打ち抜きピンのような非圧縮層が存在する時にも生ずる。 For example, in Japanese Patent Laid-Open No. 6-198497, there is a molding method for obtaining a molded body having a stepped lower end portion by compressing powder filled in a die using a concentrically fitted lower punch, and filling the inside of the die. It is disclosed. In this case, the relative moving speed of the upper punch and the lower punch with respect to the die is controlled by setting the same speed ratio as the ratio of the compression amount of each step of the molded product. When compression molding such multi-stage powder compacts, changing the compression ratio of each step part means that during the compression molding, the powder moves from a step part with a high compression density to a lower part part and a good compact is obtained. I can't. Similar movement of the powder occurs when there is an uncompressed layer, such as a punched pin, inside the packed powder layer to be compressed.

このような現象は非圧縮層の体積及び充填する粉末の圧縮量によって影響を受ける。例えば、加工工具などを燒結により製造する場合、粉末成形体に軸孔を形成し、更に圧縮密度を２．５程度に高くして燒結後の強度を向上することがある。また、製造する部品によっては圧縮率を３に設定して圧縮成形する場合もある。このような場合は粉末の充填量が増加するため上記の不都合が更に顕著となる。したがって、非圧縮層に係る充填層と他の充填層とが一定圧縮比となるように、粉末を充填するときに打ち抜きピンなどの非圧縮層の形状に適合する粉末の充填をする必要がある。 Such a phenomenon is affected by the volume of the non-compressed layer and the amount of powder to be filled. For example, when a processing tool or the like is manufactured by sintering, a shaft hole is formed in the powder compact, and the compression density may be increased to about 2.5 to improve the strength after sintering. Further, depending on the parts to be manufactured, compression molding may be performed with the compression ratio set to 3. In such a case, the above-mentioned inconvenience becomes more remarkable because the powder filling amount increases. Therefore, it is necessary to fill a powder that matches the shape of the non-compressed layer such as a punching pin when filling the powder so that the packed layer related to the non-compressed layer and the other packed layer have a constant compression ratio. .

図1（ａ）に示す粉末成形体１は、上記先行技術に開示された打ち抜きピンにより形成された軸孔２を有し、図２示すようにダイ内部に打ち抜きピンの外形形状に適合するように充填された粉末を上下パンチにより圧縮率を３として圧縮成形したものである。図２において、２は軸孔を形成する位置を示し、粉末成形体１の体積と圧縮率とから算出された粉末量を均一な粉末の充填層３（以下、充填粉末層という）と該充填粉末層３の上下に形成される充填層４に配分して充填し、充填層４は充填粉末層３の上下に打ち抜きピンの形状を考慮して配分した粉末層（以下、補充粉末層という）である。得られた粉末成形体１は、圧縮率が３と高いためパンチに近接する上下層とニュートラルゾーンｂ部の圧縮密度差又はａ部と他の部分との圧縮密度差が大きくなり、粉末成形体１を燒結すると例えば図１（ｂ）に示すような変形が生じた。更に、図２に示すように打ち抜きピンのような非圧縮層の形状に適合するように粉末を充填することは、上下パンチにより規制される粉末成形品の端面形状と非圧縮層の上下端面形状が一致しない場合は困難である。
特開２００１−０８９８０２号公報特開平６−１９８４９７号公報 A powder molded body 1 shown in FIG. 1 (a) has a shaft hole 2 formed by the punching pin disclosed in the above prior art, and fits the outer shape of the punching pin inside the die as shown in FIG. The powder filled in is compression molded with an upper and lower punch at a compression ratio of 3. In FIG. 2, 2 indicates the position where the shaft hole is formed, and the amount of powder calculated from the volume and compressibility of the powder compact 1 is the uniform powder filling layer 3 (hereinafter referred to as the filling powder layer) and the filling. The filling layer 4 is distributed and filled in the filling layer 4 formed above and below the powder layer 3, and the filling layer 4 is distributed above and below the filling powder layer 3 in consideration of the shape of the punching pin (hereinafter referred to as supplementary powder layer). It is. Since the obtained powder compact 1 has a high compression ratio of 3, the compressive density difference between the upper and lower layers close to the punch and the neutral zone b part or the compressive density difference between the part a and the other part becomes large. When 1 was sintered, for example, deformation as shown in FIG. Furthermore, as shown in FIG. 2, filling the powder so as to conform to the shape of the non-compressed layer such as a punching pin, the shape of the end surface of the powder molded product regulated by the upper and lower punches and the shape of the upper and lower end surfaces of the non-compressed layer If they do not match, it is difficult.
JP 2001-089802 A JP-A-6-198497

本発明は、非圧縮層を有する充填粉末層を圧縮成形する場合に適した粉末の充填方法と圧縮方法からなる粉末成形体の製造方法を提供し、更にかかる製造方法による粉末成形体を用いた高強度の燒結部品を提供することを目的とする。 The present invention provides a powder molding method comprising a powder filling method and a compression method suitable for compression molding a packed powder layer having an uncompressed layer, and further uses a powder molded body by such a manufacturing method. An object is to provide a high strength sintered part.

上記課題を解決するため本発明は、成形体の外周面を形成するダイと、ダイ内部を相対的に移動する上下の成形用パンチと、該パンチの移動量を制御する制御手段とを備える成形装置により、非圧縮層を含む充填粉末層を圧縮して粉末成形体を製造する製造方法において、前記成形用パンチとは独立して駆動可能な上下の粉末補充用パンチを前記非圧縮層の投影領域の外方位置に前記成形用パンチに隣接して設け、前記非圧縮層の体積を除く粉末成形体の体積と圧縮率とから算出される粉末量を前記上下の成形用パンチ間に形成される充填粉末層と該充填粉末層の上下に前記粉末補充用パンチで圧縮可能に形成される補充粉末層とに配分する工程と、前記成形用パンチと粉末補充用パンチとを同時に圧縮成形を完了するように移動量を制御することにより、補充粉末層の粉末を充填粉末層に補充しながら圧縮成形する圧縮工程とを有することを特徴とする。 In order to solve the above problems, the present invention is a molding comprising a die that forms the outer peripheral surface of a molded body, upper and lower molding punches that move relatively inside the die, and a control means that controls the amount of movement of the punch. In a manufacturing method for manufacturing a powder compact by compressing a packed powder layer including an uncompressed layer by an apparatus, upper and lower powder replenishing punches that can be driven independently of the molding punch are projected onto the uncompressed layer. A powder amount calculated from the volume of the powder molded body excluding the volume of the non-compressed layer and the compression ratio is formed between the upper and lower molding punches. The step of allocating the filling powder layer and the replenishment powder layer formed above and below the filling powder layer so as to be compressible by the powder replenishment punch, and the molding punch and the powder replenishment punch are simultaneously completed. To control the amount of movement It makes and having a compression step of compression molding while replenishing the filling powder layer of powder replenishing powder layer.

かかる構成によれば、上記充填工程と移送工程とにより非圧縮層の体積を除く粉末成形体の体積と圧縮率とから算出される粉末量を前記上下の成形用パンチ間の充填粉末層と、該充填粉末層の上下に前記粉末補充用パンチで圧縮可能に形成される補充粉末層とに配分し、補充粉末層の粉末を粉末補充用パンチにより圧縮して充填粉末層に補充しながら圧縮成形される。それにより、圧縮工程において非圧縮層による影響を回避することができ、所定の圧縮比の粉末成形体を得ることができると共に、成形された粉末成形体の内層における圧縮密度の偏差も少なく燒結により変形することがない。 According to such a configuration, the filling powder layer between the upper and lower molding punches, the amount of powder calculated from the volume and compression rate of the powder compact excluding the volume of the non-compressed layer by the filling step and the transfer step, The replenishment powder layer formed so as to be compressible by the powder replenishment punch is disposed above and below the filling powder layer, and the powder of the replenishment powder layer is compressed by the powder replenishment punch and replenished to the filling powder layer and compression molded. Is done. As a result, the influence of the non-compressed layer in the compression process can be avoided, and a powder compact having a predetermined compression ratio can be obtained, and the compacted powder has a small deviation in the compression density in the inner layer. There is no deformation.

更に本発明は、前記充填粉末量を配分する工程は、前記ダイと下成形用パンチと該下成形パンチより下方に位置する下粉末補充用パンチとで形成される空間内に前記算出した粉末量を充填する充填工程と、上成形用パンチ及び上粉末補充用パンチを充填粉末の上面まで下動し、上下成形用パンチの間隔を維持しながら上下粉末補充用パンチに対して下方に移動させて上下成形用パンチ間の充填粉末層と上下粉末補充用パンチにより前記充填粉末層の上下に形成される補充粉末層とを形成する移送工程とからなることを特徴とする。 Further, in the present invention, in the step of allocating the filling powder amount, the calculated powder amount in a space formed by the die, a lower molding punch, and a lower powder replenishment punch positioned below the lower molding punch. And the upper molding punch and the upper powder replenishing punch are moved down to the upper surface of the filling powder and moved downward relative to the upper and lower powder replenishing punch while maintaining the interval between the upper and lower molding punches. And a transfer step of forming a filling powder layer between upper and lower molding punches and a replenishing powder layer formed above and below the filling powder layer by upper and lower powder replenishing punches.

かかる構成により、一度の充填工程と一度の移送工程で充填粉末層の上下に補充粉末層を形成することが可能となる。 With this configuration, it is possible to form a replenishment powder layer above and below the filling powder layer in a single filling step and a single transfer step.

更に本発明においては、前記ダイの側面に粉末成形体に軸穴を形成する打ち抜きピン装置を備え、前記移送工程終了後に該打ち抜きピンを充填粉末層に挿通し、打ち抜きピンを挿通した状態で前記圧縮工程を行うものにおいて、前記打ち抜きピンの投影領域の外方に、ダイの内面から離間して配置される粉末補充用パンチを上下に夫々設け、前記非圧縮層の体積を除く粉末成形体の体積と圧縮率とから算出される粉末量は、非圧縮層の体積を打ち抜きピンの体積として算出し、少なくとも該算出粉末量を前記充填粉末層と前記補充粉末層とに配分し、前記圧縮工程完了後に打ち抜きピンを引き抜くことを特徴とする。 Further, in the present invention, a punching pin device for forming a shaft hole in the powder molded body on the side surface of the die is provided, and after the transfer step, the punching pin is inserted into the filled powder layer, and the punching pin is inserted in the state where the punching pin is inserted. In the compressing step, a powder replenishing punch is provided above and below the projected area of the punching pin and spaced apart from the inner surface of the die. The amount of powder calculated from the volume and the compression ratio is calculated by calculating the volume of the uncompressed layer as the volume of the punching pin, allocating at least the calculated amount of powder to the filled powder layer and the supplementary powder layer, and the compressing step The punching pin is pulled out after completion.

かかる構成によれば、軸孔を備える設計通りの圧縮密度の粉末成形体が従来の多段プレスを用いて容易に製造することができ、かかる製造方法により製造された粉末成形体を燒結することにより、支持するための軸孔を備えて且つ強度が大きい加工工具を安価に製造することができる。 According to this configuration, a compacted powder compact with a shaft hole as designed can be easily manufactured using a conventional multi-stage press, and by sintering the powder compact manufactured by such a manufacturing method, A machining tool having a shaft hole for supporting and having high strength can be manufactured at low cost.

更に本発明によれば、前記補充粉末層に配分される粉末量は、前記算出された粉末量のうち非圧縮時における非圧縮層の水平投影領域の粉末量を（圧縮比−１）倍して算出される粉末量であることを特徴とする。かかる構成によれば、適切な補充粉末層の粉末量が粉末成形体の設計時点で算出できるので、補充粉末層の配置が容易に設定でき、パンチの設計や、充填工程における粉末補充パンチの位置制御が容易となる。 Furthermore, according to the present invention, the amount of powder distributed to the replenishment powder layer is multiplied by (compression ratio-1) of the calculated amount of powder in the horizontal projection region of the non-compressed layer during non-compression. The amount of the powder is calculated as follows. According to such a configuration, the powder amount of the appropriate replenishment powder layer can be calculated at the time of designing the powder compact, so that the arrangement of the replenishment powder layer can be easily set, the design of the punch, and the position of the powder replenishment punch in the filling process Control becomes easy.

更に本発明においては、前記圧縮工程は、前記上下成形用パンチと上下粉末補充用パンチとを、夫々の圧縮工程における全移動量の一定比に相当する移動量を夫々移動させて前記充填粉末層と補充粉末層とを予備圧縮する予備圧縮工程と、前記予備圧縮工程後に前記上下成形用パンチを固定した状態で前記上下粉末補充用パンチを所定量移動して補充粉末層から粉末を予備圧縮された充填粉末層に補充する粉末補充工程と、前記上下成形用パンチと上下粉末補充用パンチを駆動して所定形状の粉末成形体とする最終圧縮工程とからなることを特徴とする。 Further, in the present invention, in the compression step, the upper and lower molding punches and the upper and lower powder replenishment punches are moved by a movement amount corresponding to a fixed ratio of the total movement amount in each compression step, respectively. And a pre-compression process for pre-compressing the replenishment powder layer, and after the pre-compression process, the upper and lower powder replenishment punches are moved by a predetermined amount while the upper and lower molding replenishment punches are fixed, and the powder is pre-compressed from the replenishment powder layer A powder replenishing step of replenishing the filled powder layer, and a final compression step of driving the upper and lower molding punches and the upper and lower powder replenishing punches into a powder compact of a predetermined shape.

かかる構成によれば、補充粉末層の粉末の大部分を充填粉末層の粉末密度が補充に適する時期に補充することができるので、粉末成形体内層の圧縮密度の偏差を少なくすることができ、粉末密度が高くなってからの粉末移動が回避され粉末成形体の品質の維持がはかれる。 According to such a configuration, since most of the powder of the replenishing powder layer can be replenished at a time when the powder density of the filling powder layer is suitable for replenishment, the deviation of the compressed density of the powder molded body layer can be reduced, The movement of the powder after the powder density is increased is avoided, and the quality of the powder compact is maintained.

以下に本発明による粉末成形体の製造方法について、図面を参照して説明する。図1（ａ）は軸孔を有する粉末成形体を示す図面で、図１（ｂ）は図１（ａ）の粉末成形体を燒結した後の状態を示す図。図２は図１に示す粉末成形体の圧縮成形前における粉末の充填状態を示す図である。図３（ａ）、（ｂ）、（ｃ）、（ｄ）は本発明による粉末成形体の製造方法における充填粉末の配分工程をを説明するための断面図である。図４（ａ）、（ｂ）、（ｃ）、（ｄ）は本発明による粉末成形体の製造方法における粉末の圧縮工程を説明するための概略図である。図５（ａ）、（ｂ）は本発明による粉末成形体を燒結して得られる一実施形態の工具を示す平面図並びに側面図である。図６、図７は補充粉末量を説明するための説明図である。図８（ａ），（ｂ）は打ち抜きピンの作動を示す概略図である。 A method for producing a powder molded body according to the present invention will be described below with reference to the drawings. FIG. 1A is a view showing a powder molded body having a shaft hole, and FIG. 1B is a view showing a state after the powder molded body of FIG. 1A is sintered. FIG. 2 is a view showing a powder filling state before compression molding of the powder compact shown in FIG. FIGS. 3A, 3B, 3C and 3D are cross-sectional views for explaining a filling powder distribution step in the method for producing a powder molded body according to the present invention. 4 (a), 4 (b), 4 (c) and 4 (d) are schematic views for explaining a powder compression step in the method for producing a powder molded body according to the present invention. 5A and 5B are a plan view and a side view showing a tool according to an embodiment obtained by sintering a powder compact according to the present invention. 6 and 7 are explanatory diagrams for explaining the amount of supplement powder. 8A and 8B are schematic views showing the operation of the punching pin.

本実施形態においては、図４（ｄ）に示すニュートラルゾーンに軸孔２を有する単純な直方体の粉末成形体の製造方法について説明する。製造装置として図示しないＮＣ制御式の多段プレスを使用し、粉末としてバインダーを混合した炭化タングステンＷＣ粉末を使用して行った。図３（ｂ）に示す断面長方形のダイ５の側面には充填粉末層３に軸孔２を形成するための打ち抜きピン装置（図示せず）が図３（ｂ）の紙面に対して垂直方向に配設されている。多段プレスの下ラムに取り付ける下パンチは７ａ、７ｂ、７ｃと別の下ラムに取り付けられ、軸孔２の投影領域の外に位置するパンチ８ａ、８ｂとに分割されている。これと対応して多段プレスの上ラムに取り付けられる上パンチも９ａ、９ｂ、９ｃと別の上ラムに取り付けられる１０ａ、１０ｂとに分割されている。 In the present embodiment, a method for manufacturing a simple rectangular parallelepiped powder compact having a shaft hole 2 in the neutral zone shown in FIG. An NC controlled multi-stage press (not shown) was used as a manufacturing apparatus, and tungsten carbide WC powder mixed with a binder was used as the powder. A punching pin device (not shown) for forming the shaft hole 2 in the filling powder layer 3 is provided on the side surface of the die 5 having a rectangular cross section shown in FIG. 3B in a direction perpendicular to the paper surface of FIG. It is arranged. The lower punch attached to the lower ram of the multistage press is attached to 7a, 7b, 7c and another lower ram, and is divided into punches 8a, 8b located outside the projection area of the shaft hole 2. Correspondingly, the upper punch attached to the upper ram of the multi-stage press is also divided into 9a, 9b, 9c and 10a, 10b attached to another upper ram.

後述するように本実施の形態においては、下パンチ７ａ、７ｂ、７ｃと上パンチ９ａ、９ｂ、９ｃとは夫々一体に作動して粉末を圧縮成形する成形用パンチを構成し、下パンチ８ａ、８ｂと上パンチ１０ａ、１０ｂとは夫々一体に作動して粉末を補充する粉末補充用パンチを構成する。上下の各パンチの作動及び移動量は多段プレスのＮＣ制御装置を構成する記憶装置に予め設定しておくことにより制御する。 As will be described later, in the present embodiment, the lower punches 7a, 7b, 7c and the upper punches 9a, 9b, 9c each constitute a molding punch that compresses and forms a powder, and the lower punch 8a, 8b and the upper punches 10a and 10b constitute a powder replenishing punch that operates integrally to replenish powder. The operation and the amount of movement of each of the upper and lower punches are controlled by setting in advance in a storage device that constitutes the NC control device of the multistage press.

粉末の充填工程において、各下成形用パンチ７ａ、７ｂ、７ｃ及び下補充用パンチ８ａ、８ｂはＮＣ制御装置の指令に基づいて移動してダイ５上端面からの距離を図３（ａ）に示す位置に固定した。公知の粉末充填装置によりダイ５内部にＷＣ粉末を上端面まで充填した。充填した粉末量は成形後の粉末成形体１を構成する粉末量、即ち軸孔２に相当する体積（打ち抜きピンの体積）を差し引いた粉末成形体１の実体積と圧縮率から算出し、打ち抜きピンによって打ち抜かれる粉末量を加算した。 In the powder filling process, the lower forming punches 7a, 7b, 7c and the lower replenishing punches 8a, 8b are moved based on a command from the NC controller, and the distance from the upper end surface of the die 5 is shown in FIG. Fixed in the position shown. The WC powder was filled up to the upper end surface in the die 5 by a known powder filling device. The amount of filled powder is calculated from the amount of powder constituting the powder compact 1 after molding, that is, the actual volume of the powder compact 1 obtained by subtracting the volume corresponding to the shaft hole 2 (volume of the punching pin) and the compression ratio. The amount of powder punched by the pin was added.

粉末の充填が完了の後、各上成形用パンチ９ａ、９ｂ、９ｃ及び上粉末補充用パンチ１０ａ、１０ｂを充填されたＷＣ粉末上面に接するダイ５の上端位置まで下方に移動させ、続いて移送工程に移る。移送工程においては、上成形用パンチ９ａ、９ｂ、９ｃと下成形用パンチ７ａ、７ｂ、７ｃとを図示の間隔を維持したまま下方に図の４ｂに相当する量だけ移送させ、図３（ｂ）に示す状態とした。本実施形態の移送工程においては成形体に形成する軸孔の軸心をダイに設置してある打ち抜きピンの軸線に一致した位置に整合する必要があり、必要に応じて上粉末補充用パンチ１０ａ、１０ｂと下粉末補充用パンチ８ａ、８ｂとを含む全てのパンチをダイに対して相対的に同量移動させて軸孔２の軸心と打ち抜きピンの軸線とを一致させるための位置調整を行った。 After the powder filling is completed, the upper forming punches 9a, 9b, 9c and the upper powder replenishing punches 10a, 10b are moved downward to the upper end position of the die 5 in contact with the top surface of the filled WC powder, and subsequently transferred. Move on to the process. In the transferring step, the upper forming punches 9a, 9b, 9c and the lower forming punches 7a, 7b, 7c are transferred downward by an amount corresponding to 4b in the figure while maintaining the interval shown in FIG. ). In the transfer process of this embodiment, it is necessary to align the axis of the shaft hole formed in the molded body with the position corresponding to the axis of the punching pin installed in the die, and if necessary, the upper powder replenishing punch 10a. 10b and the lower powder replenishing punches 8a and 8b are moved by the same amount relative to the die to adjust the position of the shaft hole 2 to coincide with the axis of the punch pin. went.

図３（ｂ）において、上記移送工程後に形成される４ａ、４ａが下側の補充粉末層であり、４ｂ、４ｂが上側の補充粉末層である。本実施形態においては、補充粉末層４ａ、４ｂの補充粉末層の全粉末量は、圧縮工程において非圧縮層（打ち抜きピン）の影響を受ける粉末量に相当する量である。この粉末量が充填粉末層３の上下に、図２において破線で示す打ち抜きピンの投影領域の外方において、左右に且つダイ５の内面から離間した位置に４つに分割された補充粉末層として配分されている。非圧縮層の影響を受ける補充粉末量については後述する。本実施の形態においては、移送工程終了後に軸孔２と同径の打ち抜きピンを充填粉末層３に挿入して、打ち抜きピンを充填粉末層３に挿通させた状態のまま以降の圧縮工程を行った。 In FIG.3 (b), 4a, 4a formed after the said transfer process is a lower supplementary powder layer, and 4b, 4b is an upper supplementary powder layer. In the present embodiment, the total powder amount of the replenishment powder layers of the replenishment powder layers 4a and 4b is an amount corresponding to the amount of powder affected by the non-compression layer (punching pin) in the compression step. As a replenishment powder layer divided into four above and below the filling powder layer 3, outside the projected region of the punching pin indicated by a broken line in FIG. 2, left and right and at a position spaced from the inner surface of the die 5. Allocated. The amount of replenishment powder affected by the non-compressed layer will be described later. In the present embodiment, a punching pin having the same diameter as the shaft hole 2 is inserted into the filling powder layer 3 after the transfer step, and the subsequent compression process is performed with the punching pin inserted into the filling powder layer 3. It was.

次に補充粉末層を構成する粉末量について説明する。図６は軸孔２が偏奇している粉末成形体１の圧縮方向の断面を示す。この断面において、軸孔２の上端近傍即ち非圧縮層の上端近傍を通る圧縮方向と直角をなす水平面Ｐ１と、軸孔２の下端近傍即ち非圧縮層の下端近傍を通る圧縮方向と直角をなす水平面Ｐ２とにより上層Ｗ１、中間層Ｗ２、下層Ｗ２に区分すると、上層Ｗ１及び下層Ｗ３は非圧縮層の影響は受けない。 Next, the amount of powder constituting the replenishing powder layer will be described. FIG. 6 shows a cross section in the compression direction of the powder compact 1 in which the shaft hole 2 is uneven. In this cross section, the horizontal plane P1 perpendicular to the compression direction passing through the vicinity of the upper end of the shaft hole 2, that is, the vicinity of the upper end of the non-compression layer, and the compression direction passing through the vicinity of the lower end of the shaft hole 2, that is, the lower end of the non-compression layer. When divided into the upper layer W1, the intermediate layer W2, and the lower layer W2 by the horizontal plane P2, the upper layer W1 and the lower layer W3 are not affected by the non-compressed layer.

図から明らかなように中間層Ｗ２に相当する粉末が圧縮時に非圧縮層２の影響を受ける。図７が粉末の充填状態を模式的に示す図で、符号は図３に示す符号と同一の符号を付してある。図７（ａ）は圧縮率が３の場合における粉末充填の状態を単位粉末量に区画して示したものである。３は充填粉末層であり、４（ａ）、４（ｂ）が補充粉末層である。補充粉末層の量は、圧縮率が１に相当する粉末量は圧縮時の横方向移動とは関係がないので、図７（ｃ）に示す成形後の非圧縮層に影響を受ける中間層Ｗ２に圧縮率３を掛けた粉末量から圧縮率１に相当する量を差し引いた粉末量、即ち非圧縮時における非圧縮層の水平投影領域における粉末量の２倍の量である。図７（ｂ）は圧縮率２の場合であり、補充粉末層４（ａ）、４（ｂ）の粉末量は、図７（ｃ）に示す成形後の非圧縮層に影響を受ける中間層Ｗ２に相当する量、即ち非圧縮時における非圧縮層の水平投影領域における粉末量に圧縮率２を掛けた粉末量から圧縮率１に相当する粉末量を差し引いた粉末量である。以上の結果から非圧縮層に影響を受ける粉末量を一般式で表すと、充填状態における非圧縮層の水平領域における粉末量×（圧縮比−１）となり、これが補充粉末層に配分される粉末量となる。 As is apparent from the figure, the powder corresponding to the intermediate layer W2 is affected by the non-compressed layer 2 during compression. FIG. 7 is a diagram schematically showing the powder filling state, and the reference numerals are the same as those shown in FIG. FIG. 7A shows the powder filling state when the compression ratio is 3, divided into unit powder amounts. 3 is a filling powder layer, and 4 (a) and 4 (b) are supplementary powder layers. Since the amount of the replenished powder layer is equivalent to a compression rate of 1 and the amount of powder is not related to the lateral movement during compression, the intermediate layer W2 affected by the uncompressed layer after molding shown in FIG. The amount of powder obtained by subtracting the amount corresponding to the compression rate 1 from the amount of powder obtained by multiplying the compression rate 3 by 1, that is, twice the amount of powder in the horizontal projection region of the non-compressed layer when not compressed. FIG. 7B shows a case where the compression ratio is 2, and the amount of powder in the supplementary powder layers 4 (a) and 4 (b) is influenced by the uncompressed layer after molding shown in FIG. 7 (c). The amount corresponding to W2, that is, the amount of powder obtained by multiplying the amount of powder in the horizontal projection region of the uncompressed layer at the time of non-compression by the compression rate 2, and subtracting the amount of powder corresponding to the compression rate 1. From the above results, the amount of powder affected by the non-compressed layer is expressed by a general formula, and the amount of powder in the horizontal region of the non-compressed layer in the packed state × (compression ratio-1) is obtained. Amount.

非圧縮層の断面形状が方形に近似する場合は上記式により補充粉末層の粉末量が算出されるが、上部または下部に凸部を有する非圧縮層等の場合、必ずしも凸部の頂点を通る水平面により非圧縮層の影響を受ける層を限定する必要はなく、圧縮時に前記粉末移動に影響を及ぼす非圧縮層の実質的体積を概算して求めればよい。また、非圧縮層の形状によっては実験によって適切な補充粉末層の粉末量を求めてもよい。 When the cross-sectional shape of the non-compressed layer approximates a square, the powder amount of the replenishment powder layer is calculated by the above formula. However, in the case of an uncompressed layer having a convex part at the top or bottom, it always passes through the top of the convex part. It is not necessary to limit the layer affected by the non-compressed layer by the horizontal plane, and the substantial volume of the non-compressed layer that affects the powder movement at the time of compression may be roughly calculated. Further, depending on the shape of the non-compressed layer, an appropriate amount of powder in the supplemental powder layer may be obtained by experiment.

図３（ｃ）、（ｄ）は充填粉末層及び補充粉末層を形成する他の実施形態を示す図である。図３（ｃ）において、ダイ５の上端面からの下成形用パンチ７ａ、７ｂ、７ｃと下粉末補充用パンチ８ａ、８ｂとの位置を充填粉末層３とその下側の補充粉末層４ａを形成する位置に保持して粉末の充填を行う。下成形用パンチ７ａ、７ｂ、７ｃの上面と下粉末補充用パンチ８ａ、８ｂの上面との距離は、前述した補充粉末量算出法により算出した粉末量に基づいて設定される。次いで、上成形用パンチ９ａ、９ｂ、９ｃを充填粉末層３の上端面に接するまで下動させ、上下成形用パンチの間隔を維持したまま上成形用パンチ９ａ、９ｂ、９ｃ及び下成形用パンチ７ａ、７ｂ、７ｃと下粉末補充用パンチ８ａ、８ｂとを共に前記補充粉末量に基づいて設定される４ａの高さに相当する量だけ下方に移送して、図３（ｄ）に示すように上側の補充粉末層の空間１０’ａ、１０’bを形成する。空間１０’ａ、１０’bの高さは前記補充粉末量に基づいて設定される４ａの高さに等しい。次に、この空間１０’ａ、１０’bに粉末を充填して補充粉末層４ｂを形成したのち、上粉末補充用パンチ１０ａ、１０ｂを補充粉末層４ｂの上面まで下動させて充填を完了する。即ち、図３（ｂ）に示す状態と同一となる。この状態で破線２で示す位置に打ち抜きピンが一致するように全体を移送する。 FIGS. 3C and 3D are diagrams showing another embodiment for forming a filling powder layer and a supplementary powder layer. In FIG. 3C, the positions of the lower molding punches 7a, 7b and 7c and the lower powder replenishing punches 8a and 8b from the upper end surface of the die 5 are indicated by the filling powder layer 3 and the lower replenishing powder layer 4a. The powder is filled while being held at the position to be formed. The distance between the upper surfaces of the lower molding punches 7a, 7b and 7c and the upper surfaces of the lower powder replenishing punches 8a and 8b is set based on the powder amount calculated by the above-described replenishing powder amount calculation method. Next, the upper molding punches 9a, 9b, 9c are moved downward until they contact the upper end surface of the filling powder layer 3, and the upper molding punches 9a, 9b, 9c and the lower molding punch are maintained while maintaining the distance between the upper and lower molding punches. 7a, 7b, 7c and lower powder replenishing punches 8a, 8b are both moved downward by an amount corresponding to the height of 4a set based on the replenishing powder amount, as shown in FIG. 3 (d). The upper replenishing powder layer spaces 10′a and 10′b are formed in the upper portion. The heights of the spaces 10'a and 10'b are equal to the height of 4a set based on the amount of the replenishing powder. Next, after filling the spaces 10′a and 10′b with the powder to form the replenishing powder layer 4b, the upper powder replenishing punches 10a and 10b are moved down to the upper surface of the replenishing powder layer 4b to complete the filling. To do. That is, it is the same as the state shown in FIG. In this state, the whole is transferred so that the punching pin matches the position indicated by the broken line 2.

次に図４（ａ）、（ｂ）、（ｃ）、（ｄ）を参照して圧縮工程の説明をする。図４は簡明のため総てのパンチ及びダイを省略してある。圧縮工程において、第１ステップとして予備圧縮を行った。図４（ａ）において、上成形用パンチ９ａ、９ｂ、９ｃと下成形用パンチ７ａ、７ｂ、７ｃとは圧縮開始から圧縮成形終了までの全移動量の２０％に相当する移動量で充填粉末層３を圧縮し、同時に上粉末補充用パンチ１０ａ、１０ｂと下粉末補充用パンチ８ａ、８ｂも圧縮開始から圧縮成形終了までの全移動量の２０％に相当する移動量で補充粉末層４ａ，４ｂの圧縮を行い、充填粉末層３に粉末を補充しながら図４（ｂ）に示す状態まで予備圧縮を行った。 Next, the compression process will be described with reference to FIGS. 4 (a), (b), (c), and (d). In FIG. 4, all punches and dies are omitted for simplicity. In the compression process, preliminary compression was performed as the first step. In FIG. 4 (a), the upper molding punches 9a, 9b, 9c and the lower molding punches 7a, 7b, 7c are filled with a movement amount corresponding to 20% of the total movement amount from the start of compression to the end of compression molding. At the same time, the upper powder replenishing punches 10a and 10b and the lower powder replenishing punches 8a and 8b compress the layer 3 with a movement amount corresponding to 20% of the total movement amount from the start of compression to the end of compression molding. The pre-compression was carried out to the state shown in FIG.

続いて第２ステップとして粉末補充を行った。図４（ｂ）において、上成形用パンチ９ａ、９ｂ、９ｃと下成形用パンチ７ａ、７ｂ、７ｃとを停止したまま、上粉末補充用パンチ１０ａ、１０ｂと下粉末補充用パンチ８ａ、８ｂとを圧縮成形終了までの全移動量の略６０％の移動量で補充粉末層４ａ、４ｂを圧縮して充填粉末層３に粉末の補充を行い図４（ｃ）に示す状態とした。第３ステップは最終圧縮工程であって、図４（ｃ）に示す状態から図４（ｄ）に示す粉末成形体１１となるまで上成形用パンチ９ａ、９ｂ、９ｃと下成形用パンチ７ａ、７ｂ、７ｃとを圧縮成形終了までの全移動量の８０％の移動量で充填粉末層３を圧縮させるように移動し、同時に上粉末補充用パンチ１０ａ、１０ｂと下粉末補充用パンチ８ａ、８ｂとを圧縮成形終了までの全移動量の略２０％の移動量で補充粉末層４ａ、４ｂの圧縮を行うように移動させて同時に圧縮を完了した。 Subsequently, powder replenishment was performed as a second step. In FIG. 4B, while the upper molding punches 9a, 9b, 9c and the lower molding punches 7a, 7b, 7c are stopped, the upper powder replenishing punches 10a, 10b and the lower powder replenishing punches 8a, 8b The replenishment powder layers 4a and 4b are compressed with a movement amount of about 60% of the total movement amount until the end of compression molding, and the powder is replenished to the filling powder layer 3 to obtain the state shown in FIG. The third step is a final compression process, and the upper molding punches 9a, 9b, 9c and the lower molding punch 7a from the state shown in FIG. 4 (c) to the powder compact 11 shown in FIG. 4 (d). 7b and 7c are moved so that the packed powder layer 3 is compressed by a moving amount of 80% of the total moving amount until the end of compression molding, and at the same time, the upper powder replenishing punches 10a and 10b and the lower powder replenishing punches 8a and 8b are moved. Were moved so as to compress the replenishing powder layers 4a and 4b with a movement amount of approximately 20% of the total movement amount until the end of compression molding.

圧縮成形完了後、打ち抜きピンを粉末成形体より引き抜き、下成形用パンチ７ａ、７ｂ、７ｃと下粉末補充用パンチ８ａ、８ｂとをダイ５の上端まで上昇させるか、またはダイ５を下動させるかして粉末成形体１１をダイから取出し、焼結工程に搬送する。上記記載から理解できるように、上パンチ及び下パンチは成形用パンチとそれとは独立に駆動可能な充填用パンチとで構成されていればよい。また、成形用パンチが複数に分割されていて多段状の粉末成形体を成形する場合にも、粉末補充層を形成して粉末を補充しながら圧縮成形する本発明の製造方法が適用できる。本実施形態のように単純な形状の粉末成形体の場合は、ＮＣ制御の多段プレスを使用する必要もなく、独立に駆動可能な粉末補充用パンチを上下の成形用パンチに挿通させて成形プレスに装着し、油圧制御等によるパンチの速度制御やリミットスイッチなどによるパンチの移動量制御によっても本発明の実施は可能である。上記実施形態の上下パンチの移動量はダイに対する相対的な移動量であって、ダイ固定方式でもウイズドロアル方式でもよい。 After completion of the compression molding, the punching pin is pulled out from the powder molded body, and the lower molding punches 7a, 7b, 7c and the lower powder replenishing punches 8a, 8b are raised to the upper end of the die 5 or the die 5 is moved downward. Thus, the powder compact 11 is taken out from the die and conveyed to the sintering process. As can be understood from the above description, the upper punch and the lower punch may be configured by a forming punch and a filling punch that can be driven independently of the forming punch. In addition, when the forming punch is divided into a plurality of parts and a multi-stage powder compact is formed, the manufacturing method of the present invention in which a powder replenishment layer is formed and compression molding is performed while replenishing powder can be applied. In the case of a powder compact with a simple shape as in this embodiment, it is not necessary to use an NC-controlled multi-stage press, and a powder replenishing punch that can be driven independently is inserted into the upper and lower molding punches. It is also possible to implement the present invention by controlling the punch speed by hydraulic control or the like and by controlling the amount of punch movement by a limit switch or the like. The movement amount of the upper and lower punches in the above embodiment is a relative movement amount with respect to the die, and may be a die fixing method or a withdrawal method.

また上記実施の形態においては充填粉末層の非圧縮層として打ち抜きピンについて説明したが、固体部品の外周に粉末成形体を形成する場合や中空の粉末成形体を形成するための中子を使用する場合などにも本発明の製造方法は適用できる。このような場合は、充填する粉末量は粉末成形体の全体の体積から非圧縮層の体積を差し引いた体積と圧縮率とから算出でき、補充粉末層の粉末量は非圧縮時における非圧縮層が存在する圧縮方向に対して水平な層の粉末量、即ち非圧縮時における非圧縮層の水平投影領域の粉末量×（圧縮率−１）の式により算出できる。補充粉末層を形成する位置は非圧縮層の投影領域の外方で、粉末成形品の形状に応じて均等な補充が可能な位置に一または複数に分割して設定することができる。更に、補充粉末層はダイ内面より離間して設定することが望ましい。 In the above embodiment, the punching pin has been described as the non-compressed layer of the filled powder layer. However, when forming a powder molded body on the outer periphery of a solid part or using a core for forming a hollow powder molded body The manufacturing method of the present invention can also be applied to cases. In such a case, the amount of powder to be filled can be calculated from the volume obtained by subtracting the volume of the non-compressed layer from the total volume of the powder compact and the compression ratio, and the amount of powder in the supplementary powder layer is the uncompressed layer at the time of non-compression. The amount of powder in a layer horizontal to the compression direction in which there is, that is, the amount of powder in the horizontal projection region of the non-compressed layer at the time of non-compression is calculated by the equation: The position where the replenishment powder layer is formed can be set in one or a plurality of positions outside the projection area of the non-compressed layer and at a position where uniform replenishment is possible according to the shape of the powder molded product. Furthermore, it is desirable that the replenishment powder layer is set apart from the inner surface of the die.

図５（ａ）、（ｂ）は、本発明による製造方法により成形された粉末成形体を焼結して得られた軸孔１２を有する圧縮密度が高く強度の大きい切削工具１３を示す図であって、上下パンチの形状を選択して上記の方法と同様の工程を行うことにより複雑な形状の粉末成形体を製造できることを示す。 5 (a) and 5 (b) are diagrams showing a cutting tool 13 having a high compression density and a high strength having a shaft hole 12 obtained by sintering a powder compact formed by the manufacturing method according to the present invention. Thus, it is shown that a powder compact having a complicated shape can be produced by selecting the shape of the upper and lower punches and performing the same process as the above method.

本発明による非圧縮層を含む充填粉末層を圧縮して粉末成形体を形成する製造方法によれば、上下の成形用パンチと該成形用パンチとは独立に駆動可能な上下の粉末補充用パンチを設け、非圧縮層の体積を除く粉末成形体の体積と圧縮率とから算出される粉末量を上下の成形用パンチ間に形成される充填粉末層と該充填粉末層の上下に前記粉末補充用パンチで圧縮可能に形成される補充粉末層とに配分して、圧縮される粉末の密度があまり高くならない時期に、粉末を充填粉末層に補充しながら圧縮成形を行う。それにより、圧縮密度を高くするために粉末の充填量が増加しても、非圧縮層による影響を回避でき、所定の圧縮比の粉末成形体を得ることができると共に、成形された粉末成形体の内層における密度の偏差も少なく焼結により変形することがない。 According to the manufacturing method of compressing a packed powder layer including an uncompressed layer according to the present invention to form a powder molded body, the upper and lower molding punches and the upper and lower powder replenishing punches that can be driven independently of each other The amount of powder calculated from the volume of the powder compact excluding the volume of the non-compressed layer and the compression ratio is filled between the upper and lower molding punches, and the powder is replenished above and below the filled powder layer. When the density of the powder to be compressed is not so high, compression molding is performed while replenishing the powder to the filling powder layer. As a result, even if the powder filling amount is increased to increase the compression density, the influence of the non-compressed layer can be avoided, and a powder compact having a predetermined compression ratio can be obtained, and the molded powder compact can be obtained. There is little deviation in density in the inner layer of the steel, and there is no deformation due to sintering.

粉末補充用パンチの移動による補充粉末層からの粉末補充の時期は、成形用パンチによる充填粉末層の粉末の密度に関連して設定することができる。粉末密度がかなり低い内に補充粉末量が全量補充されても補充効果がなく、粉末密度がある程度高くなった時点では先に述べた粉末の移動による成形体の不良と同等の影響をもたらす。成形用パンチの移動を停止して粉末補充用パンチを移動する予備圧縮工程後の粉末補充も、予備圧縮量及びその時に行う補充粉末量などは実験的に定める必要があるが、本実施形態の粉末成形体の場合、即ち通常燒結により製造されている部品、工具の場合で圧縮率を２．５〜３にする場合は２０％前後の予備圧縮量のときに粉末の補充を行うのが望ましい。 The timing of powder replenishment from the replenishing powder layer by the movement of the powder replenishing punch can be set in relation to the density of the powder in the filling powder layer by the forming punch. Even if the replenishment powder amount is completely replenished while the powder density is very low, there is no replenishment effect, and when the powder density is increased to some extent, the same effect as the above-mentioned defect of the compact due to the movement of the powder is brought about. The powder replenishment after the pre-compression process in which the movement of the molding punch is stopped and the powder replenishment punch is moved also needs to be experimentally determined for the pre-compression amount and the replenishment powder amount to be performed at that time. In the case of a powder compact, that is, in the case of a part or tool that is normally manufactured by sintering, and when the compression ratio is 2.5 to 3, it is desirable to replenish the powder when the pre-compression amount is around 20%. .

軸孔を有する粉末成形体及び燒結した後の状態を示す図である。It is a figure which shows the state after sintering and the powder molded object which has a shaft hole. 図１に示す粉末成形体の圧縮成形前の粉末の充填状態を示す図である。It is a figure which shows the filling state of the powder before the compression molding of the powder compact shown in FIG. 本発明による粉末成形体の製造方法における充填粉末を配分する充填工程及び移送工程を説明するための断面図である。It is sectional drawing for demonstrating the filling process and the transfer process which distribute the filling powder in the manufacturing method of the powder compact | molding | casting by this invention. 本発明による粉末成形体の製造方法における粉末の圧縮工程を説明するための概略図である。It is the schematic for demonstrating the compression process of the powder in the manufacturing method of the powder compact | molding | casting by this invention. 本発明による粉末成形体を焼結して得られる一実施形態の工具を示す平面図並びに側面図である。It is the top view and side view which show the tool of one Embodiment obtained by sintering the powder compact | molding | casting by this invention. 補充粉末量を説明するための本発明による粉末成形体の断面図である。It is sectional drawing of the powder compact | molding | casting by this invention for demonstrating the amount of replenishment powder. 補充粉末量を説明するための粉末充填状態を示す模式図である。It is a schematic diagram which shows the powder filling state for demonstrating the amount of replenishment powder. 打ち抜きピンの作動を示す概略図である。It is the schematic which shows the action | operation of a punch pin.

符号の説明Explanation of symbols

１粉末成形体、２軸孔、３充填粉末層、４補充粉末層、５ダイ、７下成形用パンチ、８下粉末補充用パンチ、９上成形用パンチ、１０上粉末補充用パンチ、１５打ち抜きピン DESCRIPTION OF SYMBOLS 1 Powder compact, 2 axial hole, 3 filling powder layer, 4 supplementary powder layer, 5 die | dye, 7 lower molding punch, 8 lower powder supplementing punch, 9 upper molding punch, 10 upper powder supplementing punch, 15 punching Pin

Claims

成形体の外周面を形成するダイと、ダイ内部を相対的に移動する上下の成形用パンチと、該パンチの移動量を制御する制御手段とを備える成形装置により、非圧縮層を含む充填粉末層を圧縮して粉末成形体を製造する製造方法において、
前記成形用パンチとは独立して駆動可能な上下の粉末補充用パンチを前記非圧縮層の投影領域の外方位置に前記成形用パンチに隣接して設け、
前記非圧縮層の体積を除く粉末成形体の体積と圧縮率とから算出される粉末量を前記上下の成形用パンチ間に形成される充填粉末層と該充填粉末層の上下に前記粉末補充用パンチで圧縮可能に形成される補充粉末層とに配分する工程と、
前記成形用パンチと粉末補充用パンチとを同時に圧縮成形を完了するように移動量を制御することにより、補充粉末層の粉末を充填粉末層に補充しながら圧縮成形する圧縮工程とを有することを特徴とする粉末成形体の製造方法。 Filled powder containing an uncompressed layer by a molding apparatus comprising a die that forms the outer peripheral surface of the molded body, upper and lower molding punches that move relatively inside the die, and a control means that controls the amount of movement of the punch. In the production method for producing a powder compact by compressing the layer,
Upper and lower powder replenishment punches that can be driven independently of the molding punches are provided adjacent to the molding punches at positions outside the projection area of the uncompressed layer,
The amount of powder calculated from the volume of the powder compact excluding the volume of the uncompressed layer and the compression ratio is used to replenish the powder above and below the filled powder layer. Distributing to a replenishment powder layer formed compressible with a punch;
A compressing step of compressing and molding the filling powder layer while replenishing the powder in the filling powder layer by controlling the amount of movement of the molding punch and the powder replenishing punch so as to complete compression molding simultaneously. A method for producing a powder compact characterized by the above.

前記充填粉末量を配分する工程は、前記ダイと下成形用パンチと該下成形パンチより下方に位置する下粉末補充用パンチとで形成される空間内に前記算出した粉末量を充填する充填工程と、
上成形用パンチ及び上粉末補充用パンチを充填粉末の上面まで下動し、上下成形用パンチの間隔を維持しながら上下粉末補充用パンチに対して下方に移動させて上下成形用パンチ間の充填粉末層と上下粉末補充用パンチにより前記充填粉末層の上下に形成される補充粉末層とを形成する移送工程とからなることを特徴とする請求項１に記載の製造方法。 The step of allocating the filling powder amount is a filling step of filling the calculated powder amount in a space formed by the die, the lower molding punch, and the lower powder replenishment punch positioned below the lower molding punch. When,
The upper forming punch and the upper powder replenishing punch are moved down to the upper surface of the filling powder and moved downward with respect to the upper and lower powder replenishing punch while maintaining the interval between the upper and lower forming punches to fill the space between the upper and lower forming punches. 2. The manufacturing method according to claim 1, further comprising a transfer step of forming a powder layer and a replenishment powder layer formed above and below the filling powder layer by upper and lower powder replenishment punches.

前記充填粉末量を配分する工程は、前記ダイと下成形用パンチと該下成形パンチより下方に位置する下粉末補充用パンチとで形成される空間内に粉末を充填する充填工程と、
上成形用パンチを充填粉末の上面まで下動し、上下成形用パンチをその間隔を維持しながら下粉末補充用パンチとともに下方に移動させて、上下成形用パンチ間の充填粉末層と下側補充粉末層を形成する移送工程と、
該移送工程により前記充填粉末層の上面に上成形用パンチに形成された空間に更に粉末を充填して上側の補充粉末層とを形成する充填工程とからなることを特徴とする請求項１に記載の製造方法。 The step of allocating the filling powder amount is a filling step of filling powder in a space formed by the die, the lower molding punch, and the lower powder replenishment punch positioned below the lower molding punch,
The upper molding punch is moved down to the upper surface of the filling powder, and the upper and lower molding punches are moved downward together with the lower powder replenishing punch while maintaining the interval, so that the filling powder layer between the upper and lower molding punches and the lower replenishment are supplied. A transfer step of forming a powder layer;
The method further comprises a filling step of filling the space formed in the upper molding punch on the upper surface of the filling powder layer with the powder by the transfer step to form an upper replenishing powder layer. The manufacturing method as described.

前記ダイの側面に粉末成形体に軸穴を形成する打ち抜きピン装置を備え、
前記移送工程終了後に該打ち抜きピンを充填粉末層に挿通し、打ち抜きピンを挿通した状態で前記圧縮工程を行うものにおいて、
前記打ち抜きピンの投影領域の外方に、ダイの内面から離間して配置される粉末補充用パンチを上下に夫々設け、
前記非圧縮層の体積を除く粉末成形体の体積と圧縮率とから算出される粉末量は、非圧縮層の体積を打ち抜きピンの体積として算出し、少なくとも該算出粉末量を前記充填粉末層と前記補充粉末層とに配分し、
前記圧縮工程完了後に打ち抜きピンを引き抜くことを特徴とする請求項１乃至４の何れか１項に記載の粉末成形体の製造方法。 A punching pin device for forming a shaft hole in the powder molded body on the side surface of the die,
In the one in which the punching pin is inserted into the filling powder layer after the transfer step is completed, and the compression step is performed in a state where the punching pin is inserted,
Provided above and below the punching pin projection area is a powder replenishment punch arranged at a distance from the inner surface of the die, respectively,
The amount of powder calculated from the volume of the powder compact excluding the volume of the non-compressed layer and the compression ratio is calculated by calculating the volume of the non-compressed layer as the volume of the punch pin, and at least the calculated powder amount Distributing to the replenishment powder layer,
The method for producing a powder compact according to any one of claims 1 to 4, wherein the punching pin is pulled out after completion of the compression step.

前記補充粉末層に配分される粉末量は、前記算出された粉末量のうち非圧縮時における非圧縮層の水平投影領域の粉末量を（圧縮比−１）倍して算出される粉末量であることを特徴とする請求項１乃至５の何れか１項に記載する製造方法。 The amount of powder distributed to the replenishment powder layer is the amount of powder calculated by multiplying the amount of powder in the horizontal projection region of the non-compressed layer at the time of non-compression among the calculated powder amounts (compression ratio-1). The manufacturing method according to any one of claims 1 to 5, wherein the manufacturing method is provided.

前記圧縮工程は、前記上下成形用パンチと上下粉末補充用パンチとを、夫々の圧縮工程における全移動量の一定比に相当する移動量を夫々移動させて前記充填粉末層と補充粉末層とを予備圧縮する予備圧縮工程と、
前記予備圧縮工程後に前記上下成形用パンチを固定した状態で前記上下粉末補充用パンチを所定量移動して補充粉末層から粉末を予備圧縮された充填粉末層に補充する粉末補充工程と、
前記上下成形用パンチと上下粉末補充用パンチを駆動して所定形状の粉末成形体とする最終圧縮工程とからなることを特徴とする請求項１に記載の粉末成形体の製造方法。 In the compression step, the filling powder layer and the supplementary powder layer are moved by moving the upper and lower molding punch and the upper and lower powder replenishment punch by a movement amount corresponding to a fixed ratio of the total movement amount in each compression step. A pre-compression process for pre-compression,
A powder replenishing step of replenishing the pre-compressed filled powder layer from the replenished powder layer by moving the upper and lower powder replenishing punch by a predetermined amount with the upper and lower molding punches fixed after the pre-compressing step;
2. The method for producing a powder compact according to claim 1, comprising a final compression step of driving the upper and lower molding punch and the upper and lower powder replenishing punch to form a powder compact having a predetermined shape.

前記上下成形用パンチの何れか一方の成形用パンチにおいて、該成形用パンチの成形面から上下に貫通する少なくとも一つの柱状の通孔を設け、該通孔内に前記成形用パンチとは独立に移動する粉末補充用パンチを備える請求項１に記載の粉末成形体の製造方法で用いる成形用パンチ構造。 In any one of the upper and lower molding punches, at least one column-shaped through hole penetrating vertically from the molding surface of the molding punch is provided, and the molding punch is independent of the molding punch. The molding punch structure used in the method for producing a powder compact according to claim 1, comprising a moving powder replenishing punch.

請求項１乃至５の何れか１項に記載の製造方法により製造された粉末成形体を焼結して製造されたことを特徴とする焼結部品。 6. A sintered part produced by sintering a powder compact produced by the production method according to claim 1.