JPH11310805A - Production of composite sintering machine part - Google Patents
Production of composite sintering machine partInfo
- Publication number
- JPH11310805A JPH11310805A JP11950398A JP11950398A JPH11310805A JP H11310805 A JPH11310805 A JP H11310805A JP 11950398 A JP11950398 A JP 11950398A JP 11950398 A JP11950398 A JP 11950398A JP H11310805 A JPH11310805 A JP H11310805A
- Authority
- JP
- Japan
- Prior art keywords
- green compact
- strength
- press
- fitting
- powder
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Powder Metallurgy (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】この発明は、粉末冶金法で金
型からの押し出しができないような複雑な形状の機械部
品を作る場合などに用いられる、複数の部分に分割して
成形した圧粉体を組み合わせて焼結することにより１箇
の焼結部品を得る方法の改良に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a green compact which is divided into a plurality of parts and is used, for example, when making a machine part having a complicated shape which cannot be extruded from a mold by powder metallurgy. And improving the method of obtaining one sintered part by sintering in combination.
【０００２】[0002]
【従来の技術】機械部品の製造における粉末冶金法の大
きな特徴の一つは、圧粉体の形状が成形金型から押し出
し可能なものである限り、切削その他の加工法に比べて
均一な製品をより高能率に量産できる点にある。しかし
例えば図１に示すＶプーリーの場合は、Ｖ溝に当たる凹
部のために金型からの押し出しが不可能で、従って一体
成形することができない。この他にも、その形状が金型
での一体成形は不可能なものが往々にしてある。2. Description of the Related Art One of the major features of powder metallurgy in the manufacture of machine parts is that, as long as the shape of a green compact can be extruded from a molding die, a uniform product can be obtained as compared with cutting and other processing methods. Can be mass-produced more efficiently. However, for example, in the case of the V pulley shown in FIG. 1, it cannot be extruded from the mold because of the concave portion corresponding to the V groove, and cannot be integrally formed. In addition, there are many cases where the shape cannot be integrally formed with a mold.
【０００３】この様な場合、目的とする製品をそれぞれ
成形可能な２つ以上の部分に分け、その一方には孔また
は凹部（以下孔と総称する）を，他の一方には軸または
突起（以下軸と総称する）を設けた形状の圧粉体を成形
し、両者の孔と軸を嵌め合わせた状態で焼結すれば所望
の製品を得ることができる。これを図１のＶプーリーに
ついて説明すると、図２に示す如くＶプーリーをそれぞ
れ成形可能な，ボス部（軸部）１１を持つ部分１０と孔
部２１を持つ部分２０に分けて成形したのち、得られた
圧粉体１０の軸部１１と圧粉体２０の孔部２１を嵌め合
わせて焼結することによってＶプーリーの完成品が得ら
れる。In such a case, the target product is divided into two or more moldable parts, one of which is provided with a hole or a recess (hereinafter collectively referred to as a hole), and the other is provided with a shaft or a projection (referred to hereinafter as a hole). A desired product can be obtained by molding a green compact having a shape provided with a shaft (hereinafter, collectively referred to as a shaft) and sintering in a state where both holes and the shaft are fitted. This will be described with reference to the V-pulley of FIG. 1. As shown in FIG. 2, the V-pulley is formed into a part 10 having a boss (shaft) 11 and a part 20 having a hole 21. The shaft 11 of the green compact 10 and the hole 21 of the green compact 20 are fitted together and sintered to obtain a completed V-pulley.
【０００４】この様な、複数の圧粉体を組み合わせてグ
リーンの状態で焼結することにより一体化した複合焼結
機械部品とする方法はかなり古く、例えば日刊工業新聞
社の「金属粉の成形」にはＰrecision metal molding
65（Ｊan. 1961）を引用してこの方法がシンターブレー
ジング（Ｓinter brazing ）の名で紹介されている。ま
た昭和41年10月発行の「ＳＴＥＥＬ」誌には複合焼結部
品の幾つかの事例と、溶浸を併用することが載ってい
る。[0004] Such a method of combining a plurality of compacts and sintering them in a green state to form an integrated composite sintered machine part is quite old. "Precision metal molding
65 (Jan. 1961), this method is introduced under the name of Sinter brazing. In addition, "STEEL" published in October 1966 describes some examples of composite sintered parts and the use of infiltration in combination.
【０００５】ところで、この様にして得られた複合焼結
部品が機械構成部品として用い得るためには接合面の強
度が特に重要であり、一体成形品に比べて遜色のない製
品を工業的に生産するには、圧粉体個々の材質選択，嵌
め合い条件，焼結方法その他多くの周辺技術が必要とな
る。これらについての既知の技術を例示すると、先ず特
公昭45− 11606号の発明では孔と軸の嵌め合い寸法差を
すきま嵌め、即ち孔の内径を軸の外径より大きく成形し
て常温での嵌め合わせを可能とするとともに、軸のある
側の圧粉体に鉄粉と銅粉の混合粉（焼結によって膨張）
を，孔のある側は鉄粉とニッケル粉の混合粉（焼結時に
よって収縮）を用い、焼結時に両部材の密着を図ってい
る。また特公昭50−1330号では、嵌め合わせて内側に来
る圧粉体は焼結寸法変化が零または膨脹になる材質，外
側に来る圧粉体は焼結寸法変化が零または収縮になる材
質を用いるとともに、焼結時に銅溶浸を併用している。By the way, in order for the composite sintered part obtained in this way to be usable as a mechanical component, the strength of the joint surface is particularly important, and a product which is comparable to an integrally molded product is industrially manufactured. Production requires the selection of the material of each compact, the fitting conditions, the sintering method, and many other peripheral technologies. Examples of known techniques for these are as follows. First, in the invention of Japanese Patent Publication No. 45-11606, the fitting dimension difference between the hole and the shaft is clearance-fitted, that is, the inner diameter of the hole is formed larger than the outer diameter of the shaft, and the fitting is performed at room temperature. Mixing is possible, and mixed powder of iron powder and copper powder (expanded by sintering) to the green compact with shaft
On the side with holes, a mixed powder of iron powder and nickel powder (shrinkage during sintering) is used to ensure close contact between the two members during sintering. According to Japanese Patent Publication No. 50-1330, the compact that comes into contact with the inside and the material that changes the sintering dimension to zero or expands, and the compact that comes to the outside uses a material that changes the sintering dimension to zero or shrinks. In addition to using copper infiltration during sintering.
【０００６】特公昭61−3362号には嵌め合い寸法差を締
まり嵌め，即ち孔の内径を軸の外径よりも小さく成形
し、孔の内径を加熱膨脹させて軸と嵌合させたのち焼結
すると接合面の強度が著しく向上すること、その際の締
め代は１０〜８０μｍが適していることが開示されてい
る。一方、特公昭62− 57682号では内側に来る圧粉体と
外側に来る圧粉体の嵌め合い寸法差が締まり嵌めの場
合、外側を加熱膨脹させて嵌合させたのち焼結するより
も、単に圧入して焼結する方がより高い接合強度を得ら
れるとしている。In Japanese Patent Publication No. 61-3362, the fitting dimension difference is tightly fitted, that is, the inner diameter of the hole is formed to be smaller than the outer diameter of the shaft, and the inner diameter of the hole is expanded by heating and fitted to the shaft. It is disclosed that the strength of the joint surface is remarkably improved when tied, and that an interference of 10 to 80 μm is suitable. On the other hand, in Japanese Patent Publication No. 62-57682, when the fitting dimension difference between the inner compact and the outer compact is a tight fit, rather than sintering after heating and expanding the outside and fitting, It is stated that simply press-fitting and sintering can obtain higher bonding strength.
【０００７】特公昭62− 35442号には焼結による結果と
しての寸法変化と焼結中の寸法変化とは必ずしも同じで
ないこと，軸のある側の圧粉体の炭素量を孔のある側よ
りも重量比で０．２％以上多くすると接合面の強度が従
来に比べ著しく向上することが開示され、また、その際
に孔のある側の鉄粉に５〜１０％のカーボニル鉄粉を添
加しておけば更に有効なことが特公平 4− 71961号に開
示されている。Japanese Patent Publication No. 62-35442 discloses that the dimensional change resulting from sintering and the dimensional change during sintering are not always the same. It is also disclosed that when the weight ratio is increased by 0.2% or more, the strength of the joint surface is significantly improved as compared with the conventional case, and at this time, 5 to 10% of carbonyl iron powder is added to the iron powder on the side having holes. It is disclosed in Japanese Patent Publication No. Hei 4-71961 that it would be even more effective.
【０００８】特公平 1− 40082号には、軸のある圧粉体
と孔のある圧粉体を嵌め合わせての焼結に銅溶浸を併用
する際に、孔のある側に０．０２％以上のホウ素を添加
しておくと接合強度が向上することが開示されている。Japanese Patent Publication No. 1-40082 discloses that when copper infiltration is used in combination with sintering of a compact having a shaft and a compact having a hole, 0.02 It is disclosed that the addition of boron in an amount of at least% improves the bonding strength.
【０００９】[0009]
【発明が解決しようとする課題】上掲のような諸研究を
基礎としつつ発明者らが積み重ねてきた経験によれば、
基本的には嵌め合い寸法差を締まり嵌めに設定して圧入
により嵌め合わせるのが結果も良く製造工程が簡単な点
で、工業的には最も好ましい手段と判断される。しかし
この場合、嵌め合わせる際の圧入代の選定が重要であっ
て、接合面を充分密着させて添加成分の拡散による合金
化を促進するためには圧入代が大きいほど好ましい訳で
あるが、大き過ぎると外側に来る，即ち孔のある圧粉体
が破壊されたり、またはクラックを生じて製品の強度の
劣化を招く。ここに「圧入代」は、外側に来る圧粉体
（以下アウターという）の孔の内径と内側に来る圧粉体
（以下インナーという）の軸の外径との寸法差であり、
圧入に伴うアウターの孔の内径拡張量に相当し、また締
まり嵌めの場合における「締め代」にも相当する。According to the experiences that the inventors have accumulated based on the above-mentioned various studies,
Basically, it is considered industrially the most preferable means that the fitting dimension difference is set to interference fit and fitting is performed by press-fitting because the result is good and the manufacturing process is simple. However, in this case, it is important to select a press-fit allowance at the time of fitting. In order to make the joining surfaces sufficiently close to each other and to promote alloying by diffusion of the additional component, a larger press-fit allowance is preferable. If it passes too far, the green compact which comes to the outside, that is, the porous body is broken or cracks occur, which leads to deterioration of the strength of the product. Here, the “press-fitting allowance” is a dimensional difference between the inner diameter of the hole of the outer compact (hereinafter referred to as “outer”) and the outer diameter of the shaft of the inner compact (hereinafter referred to as “inner”),
This corresponds to the amount of expansion of the inner diameter of the outer hole due to press-fitting, and also corresponds to the “tightening allowance” in the case of interference fit.
【００１０】このアウターの破損対策としては、圧入代
の許容限界値を小さめに設定すれば製品の不良は避けら
れるが、そうすると別の問題が生じる。それは圧粉体を
金型から押し出す際のスプリングバックによりインナー
の軸の外径，アウターの孔の内径ともバラツキを生じて
いるので、圧入代（内・外径の寸法差）の許容範囲が狭
まると両者の選択組み合わせを余儀無くされ、中間工程
での手間や費用が増したり、許容範囲外の圧粉体がロス
になることなどである。更に、圧入代が小さくなるとイ
ンナー，アウターの焼結中の密着度が低くなり、製品の
強度に影響することもある。As a countermeasure against the damage to the outer, if the allowable limit value of the press-fitting allowance is set to a small value, the defect of the product can be avoided, but this causes another problem. Because the outer diameter of the inner shaft and the inner diameter of the outer hole vary due to springback when the green compact is extruded from the mold, the allowable range of press-fitting allowance (difference between inner and outer diameters) is reduced. And forced selection of the two, which increases the labor and cost in the intermediate process and causes loss of the green compact outside the allowable range. Further, when the press-in allowance is reduced, the degree of adhesion during sintering of the inner and the outer is reduced, which may affect the strength of the product.
【００１１】この様な事情から、製品の不良回避と中間
工程での歩留まりなどのバランスを図るため、量産条件
として圧入代を５０μｍ以下に抑えていたが、その結果
には何れの面からもやや不満があり、圧入代の限界をい
ま少し、せめて７０μｍまで拡大する必要があった。圧
粉体の強化には密度を高めるのが最も容易且つ有効であ
るが、圧粉体の密度は、その部品に要求される品質特性
に基づいて規定されたものである。また密度を高めるた
めには成形圧力を高めることになるが、過度の圧力は金
型の摩耗を早めたり、歪みの増大による成形不良を招く
ことにもなる。そこでこの発明の目的は、密度の助けを
借りずにアウターの強度を高めて圧入代７０μｍでの嵌
め合わせに適合させる手段を開発し、複合焼結機械部品
の品質と生産性の向上を図ることにある。Under these circumstances, in order to balance product avoidance and yield in the intermediate process, the press-in allowance was suppressed to 50 μm or less as a mass production condition. There was dissatisfaction, and it was necessary to slightly increase the limit of the press-in allowance to at least 70 μm. Increasing the density is the easiest and most effective way to strengthen the green compact, but the density of the green compact is defined based on the quality characteristics required for the part. In order to increase the density, the molding pressure must be increased. However, excessive pressure may accelerate the wear of the mold or cause molding failure due to increased distortion. Accordingly, an object of the present invention is to develop a means for increasing the strength of the outer without the help of density and adapting the fitting with a press-fitting allowance of 70 μm, thereby improving the quality and productivity of composite sintered machine parts. It is in.
【００１２】[0012]
【課題を解決するための手段】粉末の成形に関連する諸
要因を検討した結果、圧粉体の強化には原料粉に添加す
る粉末潤滑剤を、エチレンビスステアロアミドを主成分
とするものに変更すること；成形された圧粉体を一旦１
００〜２５０℃，好ましくは１５０〜２２０℃に加熱し
てから常温に冷却すること；原料粉を金型で圧縮成形す
る際、１００〜２５０℃，好ましくは１２０〜１７０℃
の温度環境で成形すること；などの手段が有効であるこ
とを見出した。また、アウターが圧入代７０μｍでの嵌
め合いに耐える条件を求めた結果、アウターの強度が圧
粉体の抗折力試験における強度で１０ＭＰａ以上であれ
ば、圧入代を７０μｍまで拡げても何等支障なく嵌め合
いできることが確認された。ちなみに、抗折力試験によ
る強度は供試材が焼結材や溶製材の場合には曲げ強度に
属するけれども、この発明の場合は対象が未焼結の圧粉
体なので、これを抗折強度または単に強度と呼ぶことに
する。As a result of examining various factors related to powder compaction, a powder lubricant to be added to the raw material powder for strengthening the green compact is mainly composed of ethylene bis stearamide. To once;
Heating to 100 to 250 ° C, preferably 150 to 220 ° C, and then cooling to room temperature; when the raw material powder is compression-molded in a mold, 100 to 250 ° C, preferably 120 to 170 ° C.
It is found that such a method is effective in molding at a temperature environment of In addition, as a result of determining the conditions under which the outer withstands the fitting at the press-fitting allowance of 70 μm, if the strength of the outer is 10 MPa or more in the bending strength test of the green compact, there is no problem even if the press-fitting allowance is increased to 70 μm. It was confirmed that they could be fitted without any problems. Incidentally, the strength of the bending strength test belongs to the bending strength when the test material is a sintered material or a smelted material, but in the case of the present invention, since the target is an unsintered green compact, the strength is determined by the bending strength. Or simply called strength.
【００１３】そこでこの発明においては、アウターの成
形に際して必要に応じて上述の強化手段を適宜に用いて
抗折強度を１０ＭＰａ以上とし、このアウターとインナ
ーとを圧入代の上限が７０μｍの締まり嵌めで嵌め合わ
せることにより、前述の課題を解決したものである。Therefore, in the present invention, when forming the outer, the bending strength is set to 10 MPa or more by appropriately using the above-described reinforcing means as necessary, and the outer and the inner are tightly fitted with each other by an interference fit with an upper limit of a press-fitting margin of 70 μm. The above-mentioned problem has been solved by fitting.
【００１４】[0014]
【発明の実施の形態】原料粉に添加する粉末潤滑剤とし
て、従来代表的なものはステアリン酸亜鉛，ステアリン
酸リチウムその他の金属石鹸であるが、最近はアクラワ
ックス（商品名）などのワックス類もよく用いられてい
る。しかし発明者らの実験によれば、粉末潤滑剤にエチ
レンビスステアロアミドを主成分とするものを用いた場
合は、従来のものに比べて強度の高い圧粉体を得ること
ができる。DESCRIPTION OF THE PREFERRED EMBODIMENTS As a powder lubricant to be added to raw material powder, zinc stearate, lithium stearate and other metal soaps have been used in the past. Recently, waxes such as accra wax (trade name) have been used. Is also commonly used. However, according to experiments by the inventors, when a powder lubricant containing ethylene bis stearamide as a main component is used, a green compact having higher strength than that of a conventional powder lubricant can be obtained.
【００１５】この場合、圧粉体の強度はエチレンビスス
テアロアミドを単味で用いた場合が最も高く、その一部
を金属石鹸などで置換するとその量が増すに従い強度は
漸減し、５０％を越えると後述する（図６とその説明）
嵌め合いに必要な強度の下限（１０ＭＰａ）まで低下す
る。従って実用上は５０％未満の量ならば、エチレンビ
スステアロアミドに金属石鹸などを添加しても差し支え
ない。また、圧粉体を１００〜２５０℃，好ましくは１
５０〜２２０℃に加熱してから常温に冷却すると、常温
成形のままのものに比べて圧粉体の強度が向上する。In this case, the strength of the green compact is highest when ethylene bis stearamide is used alone, and when a part thereof is replaced with metal soap or the like, the strength gradually decreases as the amount increases, and 50%. (See FIG. 6 and its description)
The strength is lowered to the lower limit (10 MPa) required for fitting. Therefore, in practical use, if the amount is less than 50%, metal soap or the like may be added to ethylenebisstearamide. Further, the green compact is heated at 100 to 250 ° C., preferably 1 to 250 ° C.
When heated to 50 to 220 ° C. and then cooled to room temperature, the strength of the green compact is improved as compared with that of a green compact.
【００１６】（実施例１） 粉末潤滑剤の種類や圧粉体
の加熱温度が圧粉体の強度に及ぼす影響を求めた実験結
果を図３に示す。この実験における原料粉は、重量比で
銅粉１．５％，黒鉛０．７％および鉄残部に粉末潤滑剤
を０．７％添加した混合粉であり、圧粉体の密度は各試
料とも６．７ｇ／ｃｍ3 に揃えてある。このグラフの縦
軸は圧粉体の抗折力試験法（試験片の寸法…長さ２１．
７ｍｍ，横幅１２．７ｍｍ，厚さ５ｍｍ；支点間距離…
２５．４ｍｍ）による抗折強度を、横軸の温度はこの圧
粉体（抗折力試験片）に予め加熱・空冷を施したときの
最高温度をとってある。加熱温度は１００℃，１２０
℃，１５０℃，１８０℃，２１０℃および２５０℃であ
り、左端の２０℃に相当する試料は成形したままの、加
熱をしない試料である。Example 1 FIG. 3 shows the results of an experiment in which the effects of the type of powder lubricant and the heating temperature of the green compact on the strength of the green compact are shown. The raw material powder in this experiment was a mixed powder in which 1.5% by weight of copper powder, 0.7% of graphite and 0.7% of powder lubricant were added to the balance of iron, and the density of the green compact was It is adjusted to 6.7 g / cm 3 . The vertical axis of this graph indicates the bending strength test method of the green compact (size of test piece: length 21.
7mm, width 12.7mm, thickness 5mm; distance between fulcrums ...
25.4 mm), and the temperature on the abscissa indicates the maximum temperature when the green compact (flexural strength test piece) was previously heated and air-cooled. Heating temperature is 100 ° C, 120
C., 150.degree. C., 180.degree. C., 210.degree. C., and 250.degree. C., and the sample corresponding to 20.degree.
【００１７】このグラフから、先ず圧粉体を常温で成形
したままの場合、その強度は用いた粉末潤滑剤の種類に
よって異なり、ステアリン酸リチウムとステアリン酸亜
鉛はほぼ同等でアクラワックスはこれよりやや高く、エ
チレンビスステアロアミドはこれら従来のものに比べ著
しく高い値を示している。なお２種の金属石鹸はそのグ
ラフに大差がないので、ステアリン酸リチウムのデータ
で代表してある。次に供試前の試料に加熱・空冷を施し
たものでは、何れも加熱温度が１００℃以上になると圧
粉体の強度が高くなるが金属石鹸はその度合いが緩慢で
あり、２５０℃まで加熱して漸く、エチレンビスステア
ロアミドの無加熱の強度に達している。アクラワックス
は１００℃〜１５０℃の加熱温度で強度が急増してエチ
レンビスステアロアミドの値に近付き、２００℃を越え
ると同等の強度を示している。From this graph, it can be seen that when the green compact is first formed at room temperature, the strength varies depending on the type of powder lubricant used, and lithium stearate and zinc stearate are almost equivalent, and acura wax is slightly more than this. High, ethylene bis stearamide shows a significantly higher value than these conventional ones. The two metal soaps are represented by the data of lithium stearate since there is no significant difference in the graph. Next, in the case where the sample before the test was heated and air-cooled, the strength of the green compact increased when the heating temperature was 100 ° C or higher, but the degree of metal soap was slow, and the sample was heated to 250 ° C. Eventually, the unheated strength of ethylene bis stearamide is reached. Acurawax rapidly increases in strength at a heating temperature of 100 ° C. to 150 ° C., approaches the value of ethylenebisstearamide, and shows the same strength when the temperature exceeds 200 ° C.
【００１８】後述するように圧入代７０μｍでの嵌め合
いに必要なアウターの強度は１０ＭＰａ以上であるか
ら、粉末潤滑剤が金属石鹸やアクラワックスの場合には
加熱により圧粉体を強化する必要があるが、エチレンビ
スステアロアミド単味の場合は強度が充分に高いので加
熱処理する必要はなく、成形のまま嵌め合わせに供する
ことができる。図４が示すように、エチレンビスステア
ロアミドに５０％未満の金属石鹸などを加えた場合も同
様である。図４はエチレンビスステアロアミドに添加し
た金属石鹸の量（重量％）と圧粉体の強度との関係を示
すグラフで、圧粉体の強度は金属石鹸の添加量が増すに
つれてほぼ直線的に低下するが、添加量が５０％未満の
範囲では、嵌め合いに必要な強度を保っている。As will be described later, since the outer strength required for fitting with a press-fitting allowance of 70 μm is 10 MPa or more, when the powder lubricant is metal soap or Accra wax, it is necessary to strengthen the compact by heating. However, in the case of ethylene bis stearamide alone, since the strength is sufficiently high, there is no need to perform a heat treatment, and the molded product can be used for fitting as it is. As shown in FIG. 4, the same applies to a case where less than 50% of a metal soap or the like is added to ethylene bisstearamide. FIG. 4 is a graph showing the relationship between the amount (% by weight) of metal soap added to ethylenebisstearamide and the strength of the green compact. The strength of the green compact is almost linear as the amount of metal soap added increases. However, when the amount of addition is less than 50%, the strength required for fitting is maintained.
【００１９】（実施例２） また圧粉体の加熱に代えて
所定温度で温間成形、即ち原料粉を１００〜２５０℃，
好ましくは１２０〜１７０℃に予熱しておき、これを同
じく１００〜２５０℃，好ましくは１２０〜１７０℃に
保持した金型で成形すると、強度のより高い圧粉体が得
られる。図５は粉末潤滑剤にステアリン酸亜鉛を用い５
ｔ／ｃｍ2 の成形圧力で図３の例と同じ組成・寸法の圧
粉体（抗折力試験片）を温間成形した場合の、成形温度
と圧粉体の強度との関係を示している。(Example 2) In addition, instead of heating the green compact, warm compacting is performed at a predetermined temperature, that is, the raw material powder is heated to 100 to 250 ° C.
When preheated to preferably 120 to 170 ° C. and molded in a mold maintained at 100 to 250 ° C., preferably 120 to 170 ° C., a green compact having higher strength is obtained. FIG. 5 shows the results of using zinc stearate as a powder lubricant.
3 shows the relationship between the molding temperature and the strength of the green compact when a green compact (flexural strength test piece) having the same composition and dimensions as in the example of FIG. 3 is warm-formed at a molding pressure of t / cm 2 . I have.
【００２０】このグラフから分るように、圧粉体の強度
は成形温度７０℃までは常温成形の場合と殆ど変わらな
いが、それを過ぎると９０〜１２０℃の間で急激に増大
し、以後は緩やかに上昇して１５０℃を越えるとほぼ高
原状態となり、２００℃以上に高めても、それに見合う
効果は得られない。従って成形温度は、顕著な効果が安
定して得られる１２０〜１７０℃が好ましい。ちなみ
に、このグラフと図３のグラフで温度１５０℃以上での
強度を比較すると、同じ温度でも温間成形の方が著しく
上昇しているが、これは加熱状態における荷重の有無の
影響と思われる。ただし必要以上に強化しても無駄なの
で、条件が許す限り、温間成形より実施の容易な圧粉体
加熱を選ぶ方が経済的である。As can be seen from this graph, the strength of the green compact is almost the same as that at room temperature molding up to a molding temperature of 70 ° C., but after that, it sharply increases between 90 and 120 ° C. Rises slowly and exceeds 150 ° C., becomes almost a plateau state, and even if it is raised to 200 ° C. or more, the effect corresponding thereto cannot be obtained. Therefore, the molding temperature is preferably from 120 to 170 ° C. at which a remarkable effect is stably obtained. Incidentally, when comparing the strength at a temperature of 150 ° C. or more between this graph and the graph of FIG. 3, the warm forming is significantly increased even at the same temperature, which is considered to be due to the presence or absence of the load in the heated state. . However, since it is wasteful to strengthen more than necessary, it is more economical to select green compact heating that is easier to carry out than warm forming, as long as the conditions permit.
【００２１】（実施例３） 図６のグラフは圧粉体の抗
折強度と、その圧粉体をアウターとしてこれがインナー
の圧入により破損した際の圧入代の大きさとの関係を示
したものである。試験は基準寸法が内径３０ｍｍ，外径
４０ｍｍ，高さ５ｍｍの中空円筒状で、強度を種々に変
化させた数種類の圧粉体（アウター）と、それぞれの圧
粉体と同一条件で成形した抗折力試験片を用意し、アウ
ター個々の抗折強度を測定した。一方これらのアウター
に圧入するインナーの代りに、アウター内径に対する圧
入代の大きさが種々異なる炭素工具鋼のテーパーピンを
用意した。次にこれらのアウターとテーパーピンを適宜
に組み合わせて圧入を行ない、アウターが破損した組み
合わせにおける圧入代の大きさと，その圧粉体の抗折強
度を打点して図６のグラフを作成した。Example 3 The graph of FIG. 6 shows the relationship between the transverse rupture strength of the green compact and the size of the press-fit allowance when the green compact was damaged by inner press-fitting. is there. The test was conducted in the form of a hollow cylinder with reference dimensions of 30 mm inside diameter, 40 mm outside diameter, and 5 mm height, several types of green compacts (outer) with various strengths, and molded under the same conditions as each green compact. A bending force test piece was prepared, and the bending strength of each outer was measured. On the other hand, instead of the inner press-fitted into these outers, tapered pins of carbon tool steel having different press-fitting allowances with respect to the inner diameter of the outer were prepared. Next, press fitting was performed by appropriately combining the outer and taper pins, and the size of the press fit allowance and the bending strength of the green compact in the combination in which the outer was broken were plotted to produce a graph of FIG.
【００２２】このグラフはアウターとインナーを嵌め合
わせる際の圧入代が或る値の場合、アウターの抗折強度
がグラフの線以下の場合にはアウターが破損し，線より
上の場合は破損しないことを意味している。例えば、抗
折強度が７ＭＰａの圧粉体をアウターとした場合は、圧
入代が５５μｍなら破損せず、６０μｍでは破損するこ
とを示すものである。そして、グラフによれば圧入代が
７０μｍの場合の境界値は９．５ＭＰａであるから、抗
折強度が１０ＭＰａ以上の圧粉体をアウターに用いるこ
とにより、圧入代を７０μｍまで拡げるという所期の目
的が達成されることが明らかである。In this graph, when the press-fitting margin at the time of fitting the outer and the inner is a certain value, if the bending strength of the outer is below the line of the graph, the outer will be damaged, and if it is above the line, it will not be damaged. Means that. For example, when a green compact having a transverse rupture strength of 7 MPa is used as the outer layer, no breakage occurs when the press-in allowance is 55 μm, and breakage occurs when the press-in allowance is 60 μm. According to the graph, since the boundary value when the press-in allowance is 70 μm is 9.5 MPa, the intended press-in allowance is expanded to 70 μm by using a compact having a transverse rupture strength of 10 MPa or more for the outer. It is clear that the purpose is achieved.
【００２３】前述のように、圧入代が大きいほど嵌め合
わせ焼結後の製品の接合強度が高くなるので、実用し得
る圧入代の拡大は、この発明の対象とする複合焼結機械
部品の信頼性を高めることになる。また、圧入代の拡大
はアウターとインナーを組み合わせる際の適合範囲を拡
げるので、成形作業の歩留まりが向上し、組み合わせ作
業の効率も向上する。As described above, the larger the press-in allowance is, the higher the joining strength of the product after fitting and sintering is. Therefore, the practically applicable press-in allowance can be increased by increasing the reliability of the composite sintered machine parts to which the present invention is applied. Nature. In addition, since the expansion of the press-fitting cost increases the applicable range when combining the outer and the inner, the yield of the forming operation is improved, and the efficiency of the assembling operation is also improved.
【００２４】[0024]
【発明の効果】以上に詳述した通り、この発明によれ
ば、先ず強度の高い圧粉体を容易に得ることができる。
そしてアウターとインナーの嵌め合わせ焼結による複合
焼結機械部品の製造に際してアウターの抗折強度を１０
ＭＰａ以上とすることにより製品の信頼性の向上、製造
工程における歩留まりや作業効率の向上その他、この発
明の実施による利益は極めて大きいものがある。As described in detail above, according to the present invention, first, a green compact having high strength can be easily obtained.
When manufacturing a composite sintered machine part by fitting and sintering the outer and the inner, the flexural strength of the outer is increased by 10%.
By making the pressure higher than or equal to MPa, the benefits of the present invention are extremely large, in addition to the improvement of the product reliability, the improvement of the yield and the working efficiency in the manufacturing process, and the like.
【図１】一体成形のできない焼結部品の形状の例（Ｖプ
ーリー）を示す図面である。FIG. 1 is a drawing showing an example (V pulley) of a shape of a sintered part that cannot be integrally formed.
【図２】分割成形した圧粉体１０，２０を嵌め合わせて
完成品の形状を得る有様を説明する図面である。FIG. 2 is a view for explaining how to obtain a shape of a finished product by fitting divided green compacts 10 and 20 to each other.
【図３】粉末潤滑剤の種類および圧粉体の加熱温度と圧
粉体の強度との関係を示すグラフである。FIG. 3 is a graph showing the relationship between the type of powder lubricant, the heating temperature of the green compact, and the strength of the green compact.
【図４】粉末潤滑剤中の金属石鹸含有量と圧粉体の強度
との関係を示すグラフである。FIG. 4 is a graph showing the relationship between the content of metal soap in a powder lubricant and the strength of a compact.
【図５】圧粉体の温間成形温度と圧粉体の強度との関係
を示すグラフである。FIG. 5 is a graph showing the relationship between the green compacting temperature of the green compact and the strength of the green compact.
【図６】圧粉体に破損を生じる圧入代の大きさと圧粉体
の強度との関係を示すグラフである。FIG. 6 is a graph showing the relationship between the size of a press-fit allowance that causes breakage of a green compact and the strength of the green compact.
【符号の説明】 １０…Ｖプーリーの、軸部を持つ部分，１１…軸部，２
０…Ｖプーリーの、孔部を持つ部分，２１…孔部。[Explanation of Signs] 10 ... portion having shaft portion of V pulley, 11 ... shaft portion, 2
0: a portion of the V pulley having a hole, 21: a hole.
Claims (5)
粉体（以下インナーと呼ぶ。）と孔部を有する圧粉体
（以下アウターと呼ぶ。）をそれぞれ成形し、軸部と孔
部とを圧入により嵌め合わせた状態で一体に焼結するこ
とにより複雑な形状の機械部品を得るにあたり、アウタ
ーの強度を圧粉体の抗折強度値で１０ＭＰａ以上とし圧
入代を７０μｍまで拡大したことを特徴とする複合焼結
機械部品の製造方法。1. An iron-based metal powder is compressed to form a green compact having a shaft portion (hereinafter referred to as an inner) and a green compact having a hole portion (hereinafter referred to as an outer). In order to obtain a machine part with a complicated shape by sintering together with the hole part fitted by press-fitting, the outer strength is set to 10 MPa or more in the die strength of the green compact and the press-in allowance is expanded to 70 μm. A method for manufacturing a composite sintered machine part, characterized by comprising:
添加する粉末潤滑剤としてエチレンビスステアロアミド
を主成分とする潤滑剤を用いる、請求項１に記載の複合
焼結機械部品の製造方法。2. The method for manufacturing a composite sintered machine part according to claim 1, wherein a lubricant containing ethylene bis stearamide as a main component is used as a powder lubricant to be added to the raw material powder in the outer powder compacting. .
する潤滑剤が重量比で５０％未満の金属石鹸を含有す
る、請求項２に記載の複合焼結機械部品の製造方法。3. The method for producing a composite sintered machine part according to claim 2, wherein the lubricant containing ethylene bis stearamide as a main component contains less than 50% by weight of a metal soap.
アウターを１００〜２５０℃，好ましくは１５０〜２２
０℃に加熱して常温に冷却しておく、請求項１に記載の
複合焼結機械部品の製造方法。4. When the inner is press-fitted into the outer, the outer is previously heated to 100 to 250 ° C., preferably 150 to 22 ° C.
The method for producing a composite sintered machine component according to claim 1, wherein the component is heated to 0 ° C and cooled to room temperature.
１００〜２５０℃，好ましくは１２０〜１７０℃での温
間成形による、請求項１に記載の複合焼結機械部品の製
造方法。5. The method for manufacturing a composite sintered machine part according to claim 1, wherein the green compact forming the outer green compact is formed by warm compacting at a temperature of 100 to 250 ° C., preferably 120 to 170 ° C.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11950398A JPH11310805A (en) | 1998-04-28 | 1998-04-28 | Production of composite sintering machine part |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11950398A JPH11310805A (en) | 1998-04-28 | 1998-04-28 | Production of composite sintering machine part |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH11310805A true JPH11310805A (en) | 1999-11-09 |
Family
ID=14762884
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11950398A Pending JPH11310805A (en) | 1998-04-28 | 1998-04-28 | Production of composite sintering machine part |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH11310805A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2018088392A1 (en) * | 2016-11-09 | 2018-05-17 | Tdk株式会社 | Method for producing rare earth magnet |
| CN108799459A (en) * | 2018-08-13 | 2018-11-13 | 广东盈峰材料技术股份有限公司 | A kind of belt sheave structure and manufacturing method of powder metallurgy |
-
1998
- 1998-04-28 JP JP11950398A patent/JPH11310805A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2018088392A1 (en) * | 2016-11-09 | 2018-05-17 | Tdk株式会社 | Method for producing rare earth magnet |
| CN108799459A (en) * | 2018-08-13 | 2018-11-13 | 广东盈峰材料技术股份有限公司 | A kind of belt sheave structure and manufacturing method of powder metallurgy |
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