JP2018109445A - Sintered bearing - Google Patents
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Abstract
Description
本発明は、焼結軸受に関する。 The present invention relates to a sintered bearing.
焼結軸受は、無数の内部気孔を有する多孔質体であり、通常は、内部気孔に潤滑流体（例えば、潤滑油）を含浸させた状態で使用される。この場合、焼結軸受およびその内周に挿入した軸の相対回転時には、焼結軸受の内部気孔に保持された潤滑油が温度上昇に伴って焼結軸受の内周面（軸受面）に滲み出す。そして、この滲み出した潤滑油によって、焼結軸受の軸受面と軸の外周面との間の軸受隙間に油膜が形成され、軸が相対回転自在に支持される。 Sintered bearings are porous bodies having innumerable internal pores, and are usually used in a state in which internal pores are impregnated with a lubricating fluid (for example, lubricating oil). In this case, during relative rotation of the sintered bearing and the shaft inserted into the inner periphery thereof, the lubricating oil retained in the internal pores of the sintered bearing oozes into the inner peripheral surface (bearing surface) of the sintered bearing as the temperature rises. put out. The oozed lubricating oil forms an oil film in the bearing gap between the bearing surface of the sintered bearing and the outer peripheral surface of the shaft, and the shaft is supported so as to be relatively rotatable.
例えば、下記の特許文献１には、鉄および銅を主成分とする銅鉄系の焼結軸受として、鉄粉に対し１０質量％以上３０質量％未満の銅を被覆してなり、粒度を８０メッシュ以下とした銅被覆鉄粉を圧粉・焼結したものが記載されている。 For example, in Patent Document 1 below, copper and iron-based sintered bearings mainly composed of iron and copper are coated with 10% by mass or more and less than 30% by mass of copper, and the particle size is 80%. A powdered and sintered copper-coated iron powder having a mesh or less is described.
しかしながら、本発明者らが検証したところ、特許文献１の技術手段を適用した焼結軸受を振動モータに使用した場合には、軸受面が早期に摩耗して回転変動が大きくなることが明らかになった。これは、銅被覆鉄粉を成形・焼結して得られた焼結軸受では、鉄相（鉄組織）と銅相（銅組織）のネック強度が低く、軸受面を構成する粒子が剥離し易いためと考えられる。従って、かかる用途での焼結軸受を実用化するためには、鉄組織と銅組織間の結合強度を向上させることが望まれる。 However, as a result of verification by the present inventors, it is clear that when a sintered bearing to which the technical means of Patent Document 1 is applied is used for a vibration motor, the bearing surface wears out early and rotational fluctuation increases. became. This is because the sintered bearing obtained by molding and sintering copper-coated iron powder has low neck strength of the iron phase (iron structure) and copper phase (copper structure), and the particles constituting the bearing surface peel off. It is thought that it is easy. Therefore, in order to put the sintered bearing for such use into practical use, it is desired to improve the bond strength between the iron structure and the copper structure.
また、近年では、その静粛性等の利点から焼結軸受が多用途化する傾向にある。粒子間での高い結合強度を維持しながら、粉末組成等をマイナーチェンジするだけで、各用途に適合する特性を備えた焼結軸受が得られるようになれば、焼結軸受の開発コストの低廉化を図ることができ、用途の多様化に対応し、かつ焼結軸受の多品種少量生産にも適合するものとなる。 In recent years, sintered bearings tend to be versatile due to their quietness and other advantages. The development cost of sintered bearings can be reduced if sintered bearings with characteristics suitable for each application can be obtained simply by making minor changes to the powder composition while maintaining high bonding strength between particles. Therefore, it can be used for various purposes and is suitable for low-volume production of various types of sintered bearings.
そこで、本発明は、鉄組織と銅組織間で高い結合強度を有し、しかも要求特性の異なる種々の用途への対応が容易な焼結軸受を提供することを目的とする。 Therefore, an object of the present invention is to provide a sintered bearing that has a high bond strength between an iron structure and a copper structure, and that can be easily applied to various uses having different required characteristics.
本発明の焼結軸受は、支持すべき軸との間に軸受隙間を形成する軸受面を内周に有する焼結軸受であって、鉄粉に銅粉を部分拡散させてなる部分拡散合金粉と、低融点金属粉と、固体潤滑剤粉と、単体鉄粉および単体銅粉のどちらか一方もしくは双方からなる添加粉とを含む原料粉末を成形し、焼結した焼結体からなることを特徴とする。 The sintered bearing of the present invention is a sintered bearing having a bearing surface on the inner periphery that forms a bearing gap between the shaft to be supported and partially diffused alloy powder obtained by partially diffusing copper powder into iron powder. A raw material powder containing a low melting point metal powder, a solid lubricant powder, and an additive powder consisting of either or both of a single iron powder and a single copper powder, Features.
部分拡散合金粉では、銅粉の一部が鉄粉に拡散しているため、銅被覆鉄粉を使用する場合よりも焼結後の鉄組織と銅組織の間で高いネック強度が得られる。また、原料粉末を成形（圧縮成形）した後の焼結により、圧粉体に含まれる低融点金属粉が溶融する。低融点金属は銅に対して高いぬれ性を持つので、液相焼結により、隣り合う部分拡散合金粉の鉄組織と銅組織、あるいは銅組織同士を強固に結合させることができる。さらに、個々の部分拡散合金粉のうち、鉄粉の表面に銅粉の一部が拡散してＦｅ−Ｃｕ合金が形成された部分には、溶融した低融点金属が拡散していくため、鉄組織と銅組織間のネック強度を一層高めることができる。これらのことから、低温焼結でも軸受面の耐摩耗性に優れる高強度の焼結軸受を得ることが可能となる。また、部分拡散合金粉に相当量の銅粉が含まれるので、軸受面に多くの銅組織を形成することができ、そのために良好な摺動特性（低トルク性、初期なじみ性、静粛性等）を得ることができる。 In the partial diffusion alloy powder, since a part of the copper powder is diffused in the iron powder, a higher neck strength is obtained between the sintered iron structure and the copper structure than when the copper-coated iron powder is used. Moreover, the low melting point metal powder contained in the green compact is melted by sintering after the raw material powder is molded (compressed). Since the low melting point metal has high wettability with respect to copper, the iron structure and the copper structure of adjacent partial diffusion alloy powders, or the copper structures can be firmly bonded by liquid phase sintering. Furthermore, among the individual partial diffusion alloy powders, the molten low melting point metal diffuses into the part where the copper powder partly diffused on the surface of the iron powder and the Fe-Cu alloy is formed. The neck strength between the structure and the copper structure can be further increased. From these facts, it becomes possible to obtain a high-strength sintered bearing having excellent bearing surface wear resistance even at low-temperature sintering. In addition, since the partial diffusion alloy powder contains a considerable amount of copper powder, a large amount of copper structure can be formed on the bearing surface, and therefore good sliding characteristics (low torque, initial conformability, quietness, etc.) ) Can be obtained.
加えて、原料粉末に、単体鉄粉および単体銅粉のどちらか一方もしくは双方からなる添加粉を配合しているので、単体鉄粉や単体銅粉の配合量を変更することにより、高い耐摩耗性および強度と、良好な摺動特性とを満足しつつ、軸受特性を用途に合わせて調整することが可能となる。例えば単体鉄粉を加えれば、耐摩耗性や軸受強度をさらに高めることができ、単体銅粉を加えれば摺動特性を改善することができる。最低限の耐摩耗性、強度、および摺動特性を確保するため、原料粉末における部分拡散合金粉の割合は５０ｗｔ％以上にするのが好ましい。 In addition, since the additive powder consisting of one or both of single iron powder and single copper powder is blended into the raw material powder, high wear resistance can be achieved by changing the blending amount of single iron powder and single copper powder. It is possible to adjust the bearing characteristics according to the application while satisfying the properties and strength and the good sliding characteristics. For example, if single iron powder is added, wear resistance and bearing strength can be further increased, and if single copper powder is added, sliding characteristics can be improved. In order to ensure the minimum wear resistance, strength, and sliding characteristics, the proportion of the partial diffusion alloy powder in the raw material powder is preferably 50 wt% or more.
この焼結軸受としては、３００ＭＰａ以上の圧環強度を有するものが好ましい。部分拡散合金粉を主原料として使用することで、かかる圧環強度の確保も容易なものとなる。 As this sintered bearing, a bearing having a crushing strength of 300 MPa or more is preferable. By using the partial diffusion alloy powder as a main raw material, it is easy to ensure the crushing strength.
以上に述べた焼結軸受（焼結体）を得るには、原料粉末に含める部分拡散合金粉として、平均粒径５μｍ以上２０μｍ未満の銅粉が鉄粉表面に部分拡散し、かつ合金粉中にＣｕを１０〜３０質量％含有するものを使用するのが好ましい。 In order to obtain the sintered bearing (sintered body) described above, as the partial diffusion alloy powder included in the raw material powder, copper powder having an average particle size of 5 μm or more and less than 20 μm partially diffuses on the surface of the iron powder, and in the alloy powder It is preferable to use what contains 10-30 mass% of Cu.
原料粉末中に平均粒径１０６μｍを超える大粒径の部分拡散合金粉が含まれていると、焼結体の内部に粗大気孔が形成され易く、その結果、必要とされる軸受面の耐摩耗性や圧環強度等を確保できない場合があることが判明した。従って、部分拡散合金粉は、平均粒度１４５メッシュ以下（平均粒径１０６μｍ以下）のものを使用するのが好ましい。このような合金粉を使用することで、焼結後の金属組織（多孔質組織）が均一化され、金属組織中での粗大気孔の発生が抑制された焼結体を安定的に得ることができる。これにより、軸受面の耐摩耗性や軸受の圧環強度が一層向上した焼結軸受を安定的に得ることが可能となる。 If the raw material powder contains a partially diffused alloy powder having a large particle size exceeding the average particle size of 106 μm, rough air holes are likely to be formed inside the sintered body, and as a result, the required bearing surface wear resistance is required. It has been found that there are cases where it is not possible to ensure properties and crushing strength. Accordingly, it is preferable to use a partially diffused alloy powder having an average particle size of 145 mesh or less (average particle size of 106 μm or less). By using such an alloy powder, it is possible to stably obtain a sintered body in which the sintered metal structure (porous structure) is made uniform and the generation of rough atmospheric pores in the metal structure is suppressed. it can. Thereby, it becomes possible to stably obtain a sintered bearing in which the wear resistance of the bearing surface and the crushing strength of the bearing are further improved.
この焼結軸受では、低融点金属粉として錫粉、固体潤滑剤粉として黒鉛粉を使用することができる。 In this sintered bearing, tin powder can be used as the low melting point metal powder, and graphite powder can be used as the solid lubricant powder.
焼結体の鉄組織を、軟質なフェライト相を主体として構成することで、軸受面の軸に対する攻撃性を弱くすることができ、軸の摩耗を抑制することが可能となる。フェライト相を主体とした鉄組織は、例えば鉄と黒鉛が反応しない９００℃以下の温度で圧粉体を焼結することにより得ることができる。 By configuring the iron structure of the sintered body mainly with a soft ferrite phase, the aggressiveness of the bearing surface against the shaft can be weakened, and wear of the shaft can be suppressed. An iron structure mainly composed of a ferrite phase can be obtained, for example, by sintering a green compact at a temperature of 900 ° C. or less at which iron and graphite do not react.
フェライト相を主体とする鉄組織には、その全てをフェライト相とした組織の他、フェライト相の粒界にフェライト相よりも硬質のパーライト相を存在させたような鉄組織も含まれる。このように、フェライト相の粒界にパーライト相を形成することで、鉄組織をフェライト相だけで構成する場合と比べ、軸受面の耐摩耗性を向上させることができる。軸の摩耗抑制と軸受面の耐摩耗性向上とを両立させるには、鉄組織に占めるフェライト相（αＦｅ）およびパーライト相（γＦｅ）の割合を、それぞれ、８０〜９５％および５〜２０％とする（αＦｅ：γＦｅ＝８０〜９５％：５〜２０％）のが好適である。なお、上記の割合は、例えば、焼結体の任意断面におけるフェライト相およびパーライト相それぞれの面積比率で求めることができる。 The iron structure mainly composed of the ferrite phase includes an iron structure in which a pearlite phase harder than the ferrite phase is present at the grain boundary of the ferrite phase in addition to a structure in which all of the ferrite phase is formed as a ferrite phase. Thus, by forming a pearlite phase at the grain boundary of the ferrite phase, it is possible to improve the wear resistance of the bearing surface as compared with the case where the iron structure is composed only of the ferrite phase. In order to achieve both suppression of shaft wear and improvement in wear resistance of the bearing surface, the proportions of the ferrite phase (αFe) and pearlite phase (γFe) in the iron structure are 80 to 95% and 5 to 20%, respectively. (ΑFe: γFe = 80 to 95%: 5 to 20%) is preferable. In addition, said ratio can be calculated | required by the area ratio of each of the ferrite phase and the pearlite phase in the arbitrary cross sections of a sintered compact, for example.
部分拡散合金粉（Ｆｅ−Ｃｕ部分拡散合金粉）を構成する鉄粉としては、還元鉄粉を使用することができる。鉄粉としては、還元鉄粉以外にも、例えばアトマイズ鉄粉を使用することもできるが、還元鉄粉は内部気孔を有する海綿状（多孔質状）をなすことから、アトマイズ鉄粉に比べて粉末が柔らかく、圧縮成形性に優れる。そのため、低密度でも圧粉体強度を高めることができ、圧粉体の欠けや割れの発生を防止することができる。また、還元鉄粉は、上記のとおり海綿状をなすことから、アトマイズ鉄粉に比べて保油性に優れる利点も有する。 As iron powder constituting the partial diffusion alloy powder (Fe—Cu partial diffusion alloy powder), reduced iron powder can be used. As the iron powder, for example, atomized iron powder can be used in addition to the reduced iron powder. However, since the reduced iron powder has a spongy shape (porous shape) having internal pores, it is compared with the atomized iron powder. The powder is soft and excellent in compression moldability. Therefore, the green compact strength can be increased even at low density, and chipping and cracking of the green compact can be prevented. Moreover, since reduced iron powder makes a spongy shape as described above, it also has an advantage of superior oil retention as compared with atomized iron powder.
上記構成において、表層部の気孔率、特に軸受面を含む表層部の気孔率は５〜２０％とするのが好ましい。なお、ここでいう表層部とは、表面から深さ１００μｍに至るまでの領域である。 In the above configuration, the porosity of the surface layer portion, particularly the porosity of the surface layer portion including the bearing surface is preferably 5 to 20%. Here, the surface layer portion is a region from the surface to a depth of 100 μm.
焼結体（の内部気孔）には潤滑油を含浸させることができ、潤滑油としては、４０℃の動粘度が１０〜５０ｍｍ2／ｓの範囲内にあるものが好ましく使用される。軸受隙間に形成される油膜の剛性を確保しつつ、回転トルクの上昇を抑えるためである。なお、焼結体に含浸させる油としては、４０℃の動粘度が１０〜５０ｍｍ2／ｓの範囲内にある油（潤滑油）を基油とした液状グリースを採用しても良い。 The sintered body (within its internal pores) can be impregnated with a lubricating oil, and a lubricating oil having a kinematic viscosity at 40 ° C. in the range of 10 to 50 mm 2 / s is preferably used. This is to suppress the increase in rotational torque while ensuring the rigidity of the oil film formed in the bearing gap. As the oil impregnated into the sintered body, liquid grease based on oil (lubricating oil) having a kinematic viscosity at 40 ° C. within the range of 10 to 50 mm 2 / s may be employed.
この焼結軸受は、振動モータに組み込んで使用される。
振動モータは、例えば携帯電話等の携帯端末において、電話の着信やメールの受信等を報知するバイブレータとして機能するものであり、通常は、図１に示すように軸３の一端に取り付けた錘（偏芯錘）Ｗをモータ部Ｍで回転させることにより、携帯端末全体に振動を発生させる構成になっている。図１は、焼結軸受４（４１，４２）を使用した場合の振動モータ１の要部を概念的に示すもので、図示例ではモータ部Ｍの軸方向両側に突出させた軸３の両側を円筒状の焼結軸受４（４１，４２）により回転自在に支持している。錘Ｗ側の焼結軸受４１は、錘Ｗとモータ部Ｍの間に配置されており、この錘Ｗ側の焼結軸受４１は、錘Ｗと反対側の焼結軸受４２よりも厚肉でかつ大径に形成されている。二つの焼結軸受４（４１，４２）は、何れも内周に軸受面４ａを有しており、例えば金属材料で形成されたハウジング２の内周に圧入等の手段で固定されている。
This sintered bearing is used by being incorporated in a vibration motor.
The vibration motor functions as a vibrator for notifying incoming calls or mails in a portable terminal such as a cellular phone, for example. Normally, as shown in FIG. 1, a weight ( By rotating the eccentric weight (W) by the motor unit M, the entire mobile terminal is vibrated. FIG. 1 conceptually shows the main part of the vibration motor 1 when the sintered bearing 4 (41, 42) is used. In the illustrated example, both sides of the shaft 3 protruded on both sides in the axial direction of the motor part M. Is rotatably supported by a cylindrical sintered bearing 4 (41, 42). The sintered bearing 41 on the weight W side is disposed between the weight W and the motor unit M. The sintered bearing 41 on the weight W side is thicker than the sintered bearing 42 on the opposite side of the weight W. And it is formed in a large diameter. Each of the two sintered bearings 4 (41, 42) has a bearing surface 4a on the inner periphery, and is fixed to the inner periphery of the housing 2 made of, for example, a metal material by means such as press fitting.
この振動モータ１において軸３が回転すると、錘Ｗの影響を受けて軸３が軸受面４ａの全面に沿って振れ回りながら回転する。すなわち、通常用途の焼結軸受では、軸３は重力方向に偏芯した状態で回転するが、振動モータ用の焼結軸受４（４１，４２）では、図２に示すように、軸受中心Ｏｂに対して軸中心Ｏａを重力方向だけでなくあらゆる方向に偏芯させた状態で軸３が回転することになる。 When the shaft 3 rotates in the vibration motor 1, the shaft 3 rotates while swinging along the entire surface of the bearing surface 4 a under the influence of the weight W. That is, in the sintered bearing for normal use, the shaft 3 rotates while being eccentric in the direction of gravity. However, in the sintered bearing 4 (41, 42) for the vibration motor, as shown in FIG. On the other hand, the shaft 3 rotates in a state where the shaft center Oa is decentered not only in the direction of gravity but also in all directions.
近年、いわゆるスマートフォン等への搭載を考慮して、振動モータにはさらなる小型化が要請されている。振動モータを小型化した場合、モータパワーの増大には限界がある。そのような状況下でも所定の振動性能を確保するために、モータを高速回転化（１００００ｒｐｍ以上）し、あるいは錘Ｗのアンバランス荷重を増大させることで対処しようとしており、振動モータ用焼結軸受４の使用条件はより過酷化する傾向にある。 In recent years, vibration motors are required to be further downsized in consideration of mounting on so-called smartphones. When the vibration motor is downsized, there is a limit to the increase in motor power. In such a situation, in order to ensure the predetermined vibration performance, the motor is rotated at a high speed (10000 rpm or more) or the unbalance load of the weight W is increased, and the sintered bearing for the vibration motor. The usage conditions of No. 4 tend to be more severe.
本発明者らは、かかる振動モータ用焼結軸受を検討する過程において、この種の軸受では、高速回転で軸が軸受面全面にわたって振れ回ること、およびアンバランス荷重により軸受面が軸に頻繁に叩かれる（軸受面に対して軸が頻繁に摺動接触する）ことから、軸受面が通常用途の焼結軸受よりも摩耗し易いことを見出した。また回転精度を確保するためには、軸受面の精度が重要であること、さらに軸受面の精度を単に向上させるだけでは不十分で、焼結軸受をハウジング内周に圧入した際に軸受面がハウジングの内周面形状に倣って変形することも軸の回転精度に影響することも見出した。 In the process of studying such a sintered bearing for a vibration motor, the present inventors frequently rotate the shaft around the entire bearing surface at high speed rotation, and the bearing surface frequently moves on the shaft due to unbalanced load. It was found that the bearing surface is more easily worn than a sintered bearing for normal use because it is struck (the shaft frequently makes sliding contact with the bearing surface). Also, in order to ensure rotational accuracy, the bearing surface accuracy is important, and it is not sufficient to simply improve the bearing surface accuracy. When the sintered bearing is press-fitted into the inner circumference of the housing, the bearing surface It has also been found that deformation following the shape of the inner peripheral surface of the housing also affects the rotational accuracy of the shaft.
焼結軸受（焼結体）が十分な圧環強度を具備しておらず、ハウジング内周への圧入に伴って軸受面が変形し、軸受面の精度、特に真円度や円筒度が低下すると、サイジング等の形状修正加工を追加的に実行し、軸受面を適正形状に仕上げる必要がある。さらに、焼結軸受（焼結体）が十分な圧環強度を具備していないと、当該焼結軸受を組み込んだ製品（例えば携帯電話）が落下等し大きな衝撃加重が付加された場合に、軸受面が変形するおそれがある。 If the sintered bearing (sintered body) does not have sufficient crushing strength and the bearing surface is deformed as it is press-fitted into the inner periphery of the housing, the accuracy of the bearing surface, especially roundness and cylindricity, will decrease. Therefore, it is necessary to additionally perform shape correction processing such as sizing and finish the bearing surface to an appropriate shape. Furthermore, if the sintered bearing (sintered body) does not have sufficient crushing strength, a product (for example, a mobile phone) incorporating the sintered bearing will drop and a large impact load will be applied. The surface may be deformed.
振動モータ（の主軸）を支持する軸受として上記の焼結軸受を使用することにより、軸受面の耐摩耗性や強度が向上するので、回転変動を防止することができる。また、焼結体が３００ＭＰａ以上の圧環強度を有しているので、圧入時の軸受面の変形や衝撃荷重による軸受面の変形を可及的に防止することができる。 By using the sintered bearing described above as a bearing for supporting the vibration motor (the main shaft thereof), the wear resistance and strength of the bearing surface are improved, so that rotation fluctuations can be prevented. Further, since the sintered body has a crushing strength of 300 MPa or more, deformation of the bearing surface during press-fitting and deformation of the bearing surface due to an impact load can be prevented as much as possible.
以上に示すように、本発明によれば、鉄組織と銅組織間で高い結合強度を得ることができ、良好な摺動特性を確保しながら、耐摩耗性の向上や軸受強度の向上を図ることができる。また、添加粉の種類や量を調整することにより、異なる要求特性を有する焼結軸受が容易に得られるので、焼結軸受の多用途化を図ることができる As described above, according to the present invention, high bond strength can be obtained between the iron structure and the copper structure, and the wear resistance and the bearing strength are improved while ensuring good sliding characteristics. be able to. In addition, by adjusting the type and amount of the additive powder, sintered bearings having different required characteristics can be easily obtained, so that the sintered bearings can be used for many purposes.
以下、本発明の実施の形態を図面に基づいて説明する。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
図１を援用して、本発明の実施形態に係る焼結軸受４を備えた振動モータ１の要部を説明する。この振動モータ１では、直径２ｍｍ以下（好ましくは直径１ｍｍ以下）の軸３がモータ部Ｍによって１００００ｒｐｍ以上の回転数で回転駆動される。振動モータ１は、略円筒状に形成された金属製又は樹脂製のハウジング２と、モータ部Ｍの軸方向両側に配置され、ハウジング２の内周に圧入固定されたリング状の焼結軸受４（４１，４２）と、焼結軸受４（４１，４２）の内周に挿入された軸３とを備えており、軸３と焼結軸受４の軸受面４ａとの間に形成される隙間（軸受隙間）の隙間幅は、片側（半径値）で４μｍ程度に設定されている。軸３はステンレス鋼等で形成され、その一端に錘Ｗが一体又は別体に設けられている。本実施形態の錘Ｗは、その中心を軸３の中心に対して偏心させるようにして軸３の一端に取り付け固定されている。焼結軸受４の内部気孔には、４０℃の動粘度が１０〜５０ｍｍ2／ｓの範囲内にある潤滑油、もしくは４０℃の動粘度が１０〜５０ｍｍ2／ｓの範囲内にある油を基油としたグリースが含浸されている。 The main part of the vibration motor 1 including the sintered bearing 4 according to the embodiment of the present invention will be described with reference to FIG. In this vibration motor 1, the shaft 3 having a diameter of 2 mm or less (preferably 1 mm or less) is rotationally driven by the motor unit M at a rotational speed of 10,000 rpm or more. The vibration motor 1 includes a metal or resin housing 2 formed in a substantially cylindrical shape, and a ring-shaped sintered bearing 4 disposed on both axial sides of the motor portion M and press-fitted and fixed to the inner periphery of the housing 2. (41, 42) and the shaft 3 inserted in the inner periphery of the sintered bearing 4 (41, 42), and a gap formed between the shaft 3 and the bearing surface 4a of the sintered bearing 4 The gap width of (bearing gap) is set to about 4 μm on one side (radius value). The shaft 3 is formed of stainless steel or the like, and a weight W is provided integrally or separately at one end thereof. The weight W of the present embodiment is attached and fixed to one end of the shaft 3 so that the center thereof is eccentric with respect to the center of the shaft 3. Lubricating oil having a kinematic viscosity at 40 ° C. in the range of 10 to 50 mm 2 / s or oil having a kinematic viscosity at 40 ° C. in the range of 10 to 50 mm 2 / s is formed in the internal pores of the sintered bearing 4. The base oil is impregnated with grease.
以上の構成を有する軸受ユニット１において、軸３が焼結軸受４に対して相対回転すると、焼結軸受４の内部気孔に保持された潤滑油が温度上昇に伴って軸受面４ａに滲み出す。この滲み出した潤滑油によって、対向する軸３の外周面３ａと焼結軸受４の軸受面４ａとの間の軸受隙間に油膜が形成され、軸３が焼結軸受４によって相対回転自在に支持される。 In the bearing unit 1 having the above configuration, when the shaft 3 rotates relative to the sintered bearing 4, the lubricating oil held in the internal pores of the sintered bearing 4 oozes out to the bearing surface 4a as the temperature rises. Due to the oozed lubricating oil, an oil film is formed in the bearing gap between the outer peripheral surface 3a of the opposed shaft 3 and the bearing surface 4a of the sintered bearing 4, and the shaft 3 is supported by the sintered bearing 4 so as to be relatively rotatable. Is done.
なお、図示は省略するが、焼結軸受４の内部気孔に含浸させた潤滑油がハウジング２の外部に漏れ出し、あるいは飛散するのを防止するため、軸受ユニット１にはハウジング２の開口部をシールするシール部材を設けても良い。 Although illustration is omitted, in order to prevent the lubricating oil impregnated in the internal pores of the sintered bearing 4 from leaking out or scattering to the outside of the housing 2, the bearing unit 1 has an opening of the housing 2. A sealing member for sealing may be provided.
以上で説明した焼結軸受４は、主に（Ａ）原料粉末混合工程、（Ｂ）成形工程、および（Ｃ）焼結工程、を順に経て製造される。以下、上記（Ａ）〜（Ｃ）の各工程について詳細に説明する。なお、モータ部Ｍの両側に配置される二つの焼結軸受４（４１，４２）は、軸方向寸法（軸受面４ａの面積）および径方向の厚さが相互に異なるだけで、その他の構造は実質的に同一であり、同じ製造工程を経て製造される。 The sintered bearing 4 described above is mainly manufactured through (A) the raw material powder mixing step, (B) the forming step, and (C) the sintering step in this order. Hereinafter, each process of said (A)-(C) is demonstrated in detail. The two sintered bearings 4 (41, 42) arranged on both sides of the motor part M are different from each other only in the axial dimension (the area of the bearing surface 4a) and the radial thickness. Are substantially the same and are manufactured through the same manufacturing process.
（Ａ）原料粉末混合工程
この工程では、後述する複数種の粉末を混合することにより、焼結軸受４の作製用材料である原料粉末を均一化する。本実施形態で使用する原料粉末は、部分拡散合金粉と、低融点金属粉と、固体潤滑剤粉と、単体鉄粉および単体銅粉の何れか一方または双方からなる添加粉とを配合した混合粉末である。原料粉末における各粉末の質量比は、部分拡散合金粉が最も多い。この原料粉末には、必要に応じて各種成形潤滑剤（例えば、離型性向上のための潤滑剤）を添加しても良い。以下、上記の各粉末について詳細に述べる。
(A) Raw Material Powder Mixing Step In this step, the raw material powder that is a material for producing the sintered bearing 4 is made uniform by mixing a plurality of types of powders described later. The raw material powder used in the present embodiment is a mixture in which a partial diffusion alloy powder, a low melting point metal powder, a solid lubricant powder, and an additive powder composed of one or both of a simple iron powder and a simple copper powder are mixed. It is a powder. The mass ratio of each powder in the raw material powder is the largest for the partially diffused alloy powder. Various molding lubricants (for example, a lubricant for improving releasability) may be added to the raw material powder as necessary. Hereinafter, each of the above powders will be described in detail.
［部分拡散合金粉］
部分拡散合金粉１１としては、鉄粉１２の表面に銅粉１３を部分拡散させたＦｅ−Ｃｕ部分拡散合金粉が使用され、特に、本実施形態では、図４に模式的に示すように、鉄粉１２の表面に、鉄粉１２よりも平均粒径が小さい多数の銅粉１３を部分拡散させたＦｅ−Ｃｕ部分拡散合金粉が使用される。部分拡散合金粉１１の拡散部分はＦｅ−Ｃｕ合金を形成しており、図４中の部分拡大図に示すように、合金部分は鉄原子１２ａと銅原子１３ａとが相互に結合し、配列した結晶構造を有する。部分拡散合金粉１１は、１４５メッシュの篩の網目を通過可能な粒子、すなわち平均粒度１４５メッシュ以下（平均粒径１０６μｍ以下）の粒子のみが使用される。
[Partial diffusion alloy powder]
As the partial diffusion alloy powder 11, Fe-Cu partial diffusion alloy powder in which the copper powder 13 is partially diffused on the surface of the iron powder 12 is used. In particular, in the present embodiment, as schematically shown in FIG. Fe-Cu partial diffusion alloy powder obtained by partially diffusing a large number of copper powders 13 having an average particle size smaller than that of the iron powder 12 is used on the surface of the iron powder 12. The diffusion portion of the partial diffusion alloy powder 11 forms an Fe—Cu alloy, and as shown in the partial enlarged view in FIG. 4, the alloy portions are arranged in which iron atoms 12 a and copper atoms 13 a are bonded to each other. It has a crystal structure. As the partial diffusion alloy powder 11, only particles that can pass through a 145 mesh screen, that is, particles having an average particle size of 145 mesh or less (average particle size of 106 μm or less) are used.
なお、粉末はその粒径が小さくなるほど見掛密度が下がり、浮遊し易くなることから、原料粉末中に小粒径の部分拡散合金粉１１が多く含まれていると、後述する成形工程において成形金型（キャビティ）に対する原料粉末の充填性が低下し、所定形状・密度の圧粉体を安定的に得ることが難しくなる。具体的には、粒径４５μｍ以下の部分拡散合金粉１１が２５質量％以上含まれていると、上記の問題が生じ易くなることを本発明者らは見出した。従って、部分拡散合金粉１１としては、平均粒度１４５メッシュ以下（平均粒径１０６μｍ以下）で、かつ平均粒度３５０メッシュ（平均粒径４５μｍ）以下の粒子を２５質量％以上含まないものを選択使用するのが望ましい。 In addition, since the apparent density decreases as the particle size of the powder becomes smaller and the powder tends to float, if the raw material powder contains a large amount of the partial diffusion alloy powder 11 having a small particle size, the powder is molded in the molding process described later. Fillability of the raw material powder into the mold (cavity) is lowered, and it becomes difficult to stably obtain a green compact having a predetermined shape and density. Specifically, the present inventors have found that the above problem is likely to occur when the partially diffused alloy powder 11 having a particle size of 45 μm or less is contained in an amount of 25 mass% or more. Therefore, as the partial diffusion alloy powder 11, one having an average particle size of 145 mesh or less (average particle size of 106 μm or less) and not containing 25% by mass or more of particles having an average particle size of 350 mesh (average particle size of 45 μm) or less is selectively used. Is desirable.
上記の部分拡散合金粉１１を構成する鉄粉１２としては、還元鉄粉、アトマイズ鉄粉等、公知の鉄粉を使用することができるが、本実施形態では還元鉄粉を使用する。還元鉄粉は、球形に近似した不規則形状で、かつ内部気孔を有する海綿状（多孔質状）であるから、海綿鉄粉とも称される。使用する鉄粉１２は、平均粒径２０μｍ〜１０６μｍのものが好ましく、平均粒径３８μｍ〜７５μｍのものが一層好ましい。 As the iron powder 12 constituting the partial diffusion alloy powder 11, known iron powders such as reduced iron powder and atomized iron powder can be used, but reduced iron powder is used in the present embodiment. The reduced iron powder has an irregular shape that approximates a spherical shape and has a sponge shape (porous shape) having internal pores, and is also referred to as sponge iron powder. The iron powder 12 used preferably has an average particle size of 20 μm to 106 μm, and more preferably an average particle size of 38 μm to 75 μm.
また、部分拡散合金粉１１を構成する銅粉１３としては、汎用されている不規則形状や樹枝状の銅粉が広く使用可能であり、例えば、電解銅粉、アトマイズ銅粉等が用いられる。本実施形態では、表面に多数の凹凸を有すると共に、粒子全体として球形に近似した不規則形状をなし、成形性に優れたアトマイズ銅粉を使用している。使用する銅粉１３は、鉄粉１２よりも小粒径のものが使用され、具体的には平均粒径５μｍ以上２０μｍ以下（好ましくは２０μｍ未満）のものが使用される。なお、部分拡散合金粉１１におけるＣｕの割合は１０〜３０質量％（好ましくは２２〜２６質量％）である。 Moreover, as the copper powder 13 which comprises the partial diffusion alloy powder 11, the irregular-shaped and dendritic copper powder currently used widely can be used widely, for example, electrolytic copper powder, atomized copper powder, etc. are used. In the present embodiment, an atomized copper powder having a large number of irregularities on the surface, an irregular shape that approximates a spherical shape as a whole particle, and excellent in formability is used. The copper powder 13 to be used has a smaller particle diameter than the iron powder 12, and specifically, an average particle diameter of 5 μm to 20 μm (preferably less than 20 μm) is used. In addition, the ratio of Cu in the partial diffusion alloy powder 11 is 10 to 30% by mass (preferably 22 to 26% by mass).
［低融点金属粉］
低融点金属粉としては、融点が７００℃以下の金属粉、例えば錫、亜鉛、リン等の粉末が使用される。本実施形態では、これらの中でも銅と鉄に拡散し易く、単粉が使用できる錫粉１４（図６参照）、特にアトマイズ錫粉を使用する。錫粉（アトマイズ錫粉）１４としては、平均粒径５〜６３μｍのものが好ましく使用され、平均粒径２０〜４５μｍのものが一層好ましく使用される。
[Low melting point metal powder]
As the low melting point metal powder, a metal powder having a melting point of 700 ° C. or less, for example, a powder of tin, zinc, phosphorus or the like is used. In the present embodiment, tin powder 14 (see FIG. 6), particularly atomized tin powder, which can easily diffuse into copper and iron and can be used as a single powder, is used. As the tin powder (atomized tin powder) 14, one having an average particle diameter of 5 to 63 μm is preferably used, and one having an average particle diameter of 20 to 45 μm is more preferably used.
［固体潤滑剤］
固体潤滑剤としては、黒鉛、二硫化モリブデン等の粉末を一種又は二種以上使用することができる。本実施形態では、コストを考えて黒鉛粉、特に鱗片状黒鉛粉を使用する。
[Solid lubricant]
As the solid lubricant, one or more powders such as graphite and molybdenum disulfide can be used. In the present embodiment, graphite powder, particularly scaly graphite powder is used in consideration of cost.
［添加粉］
添加粉は、単体鉄粉および単体銅粉の何れか一方または双方で構成される。単体鉄粉としては、還元鉄粉およびアトマイズ鉄粉のどちらも使用可能であり、軸受の用途に応じて使用する鉄粉が選定される。なお、還元鉄粉とアトマイズ鉄粉の混合物を単体鉄粉として使用することもできる。また、単体銅粉としても、電解銅粉およびアトマイズ銅粉のどちらも使用可能であり、軸受の用途に応じて使用する銅粉が選定される。なお、電解銅粉とアトマイズ銅粉の混合物を単体銅粉として使用することもできる。単体鉄粉や単体銅粉の平均粒径は、軸受の用途に応じて広く選択することができ、例えば単体鉄粉として平均粒径４５〜２００μｍ（好ましくは１００〜１５０μｍ）の範囲内のもの、単体銅粉として平均粒径４５〜１５０μｍ（好ましくは８０〜１２５μｍ）の範囲内のものが使用可能である。単体銅粉として、原料銅粉を搗砕（Stamping）又は粉砕することで扁平化させた扁平銅粉を使用することもできる。
[Additive powder]
The additive powder is composed of one or both of simple iron powder and simple copper powder. As the simple iron powder, either reduced iron powder or atomized iron powder can be used, and the iron powder to be used is selected according to the application of the bearing. In addition, the mixture of reduced iron powder and atomized iron powder can also be used as a single-piece iron powder. Moreover, both the electrolytic copper powder and the atomized copper powder can be used as the single copper powder, and the copper powder to be used is selected according to the application of the bearing. In addition, the mixture of electrolytic copper powder and atomized copper powder can also be used as a simple substance copper powder. The average particle size of the simple iron powder or the simple copper powder can be widely selected according to the application of the bearing, for example, as a simple iron powder having an average particle size of 45 to 200 μm (preferably 100 to 150 μm), A single copper powder having an average particle diameter of 45 to 150 μm (preferably 80 to 125 μm) can be used. As the single copper powder, a flat copper powder that has been flattened by stamping or pulverizing the raw copper powder can also be used.
なお、以上に述べた各粉末の平均粒径は、粒子群にレーザ光を照射し、そこから発せられる回析・散乱光の強度分布パターンから計算によって粒度分布、さらには平均粒径を求めるレーザ回析散乱法（例えば株式会社島津製作所製のＳＡＬＤ３１０００を用いる）により測定することができる。 The average particle size of each powder described above is obtained by irradiating a particle group with laser light and calculating the particle size distribution and further calculating the average particle size from the intensity distribution pattern of diffraction / scattered light emitted therefrom. It can be measured by a diffraction scattering method (for example, using SALD31000 manufactured by Shimadzu Corporation).
（Ｂ）成形工程
成形工程では、図５ａ、図５ｂに示すような成形金型２０を使用して上記の原料粉末１０を圧縮することにより、図１等に示す焼結軸受４に近似した形状（略完成品形状）の圧粉体４’を得る。成形金型２０は、主要な構成として、同軸配置されたコア２１、上下パンチ２２，２３およびダイ２４を有する。成形金型２０は、例えばカム式成形プレス機のダイセットにセットされる。
(B) Molding process In the molding process, a shape approximated to the sintered bearing 4 shown in Fig. 1 and the like is obtained by compressing the raw material powder 10 using a molding die 20 as shown in Figs. 5a and 5b. A green compact 4 ′ (substantially finished product shape) is obtained. The molding die 20 has a core 21, upper and lower punches 22 and 23, and a die 24 that are coaxially arranged as main components. The molding die 20 is set in a die set of a cam type molding press, for example.
上記構成の成形金型２０において、コア２１、下パンチ２３およびダイ２４で画成されるキャビティ２５内に原料粉末１０を充填してから、上パンチ２２を下パンチ２３に対して相対的に接近移動させ、原料粉末１０を適当な加圧力（成形すべき圧粉体の形状や大きさに応じて設定される）で圧縮すると、圧粉体４’が成形される。そして、上パンチ２２を上昇移動させると共に下パンチ２３を上昇移動させ、圧粉体４’をキャビティ２５外に抜き出す。図６に模式的に示すように、圧粉体４’では、部分拡散合金粉１１、錫粉１４、図示しない黒鉛粉および添加粉が均一に分散している。本実施形態で使用している部分拡散合金粉１１は、鉄粉１２として還元鉄粉を使用しているため、アトマイズ鉄粉を使用した部分拡散合金粉に比べて粉末が柔らかく、圧縮成形性に優れる。そのため、低密度でも圧粉体４'の強度を高めることができ、圧粉体４'の欠けや割れの発生を防止すること
ができる。
In the molding die 20 having the above-described configuration, the raw powder 10 is filled in the cavity 25 defined by the core 21, the lower punch 23 and the die 24, and then the upper punch 22 is moved closer to the lower punch 23. When the raw material powder 10 is moved and compressed with an appropriate pressing force (set according to the shape and size of the green compact to be molded), the green compact 4 ′ is formed. Then, the upper punch 22 is moved up and the lower punch 23 is moved up, and the green compact 4 ′ is extracted out of the cavity 25. As schematically shown in FIG. 6, in the green compact 4 ′, the partial diffusion alloy powder 11, tin powder 14, graphite powder and additive powder (not shown) are uniformly dispersed. Since the partial diffusion alloy powder 11 used in the present embodiment uses reduced iron powder as the iron powder 12, the powder is softer than the partial diffusion alloy powder using atomized iron powder, and the compression moldability is improved. Excellent. Therefore, the strength of the green compact 4 ′ can be increased even at a low density, and chipping and cracking of the green compact 4 ′ can be prevented.
（Ｃ）焼結工程
焼結工程では、圧粉体４’を焼結し、焼結体を得る。焼結条件は、黒鉛（黒鉛粉）が鉄と反応しない（炭素の拡散が生じない）条件とする。鉄−炭素の平衡状態では、７２３℃に変態点があり、これを超えると鉄と炭素の反応が開始されて鉄組織中にパーライト相（γＦｅ）が生成されるが、焼結では９００℃を超えてから炭素（黒鉛）と鉄の反応が始まり、パーライト相（γＦｅ）が生成される。パーライト相（γＦｅ）は高硬度（ＨＶ３００以上）で相手材に対する攻撃性が強いため、焼結軸受４の鉄組織中に過剰にパーライト相（γＦｅ）が存在すると、軸３の摩耗を進行させるおそれがある。また、一般的な焼結軸受の製造工程では、ブタン、プロパン等の液化石油ガスと空気を混合してＮｉ触媒で熱分解させた吸熱型ガス（ＲＸガス）の雰囲気下で圧粉体を加熱・焼結させる場合が多い。しかしながら、吸熱型ガスでは炭素が拡散して圧粉体の表面を硬化させるおそれがあり、上記同様の問題が生じ易くなる。
(C) Sintering step In the sintering step, the green compact 4 'is sintered to obtain a sintered body. The sintering conditions are such that graphite (graphite powder) does not react with iron (no carbon diffusion occurs). In the iron-carbon equilibrium state, there is a transformation point at 723 ° C., and when this is exceeded, the reaction between iron and carbon is initiated and a pearlite phase (γFe) is produced in the iron structure. After that, the reaction between carbon (graphite) and iron begins, and a pearlite phase (γFe) is generated. Since the pearlite phase (γFe) has high hardness (HV300 or more) and is highly aggressive against the mating material, if the pearlite phase (γFe) is excessively present in the iron structure of the sintered bearing 4, the wear of the shaft 3 may be advanced. There is. In a general sintered bearing manufacturing process, green compacts are heated in an atmosphere of endothermic gas (RX gas), which is a mixture of liquefied petroleum gas such as butane and propane and air, and pyrolyzed with Ni catalyst.・ It is often sintered. However, in the endothermic gas, carbon may diffuse and the surface of the green compact may be cured, and the same problem as described above is likely to occur.
以上の観点から、圧粉体４’は９００℃以下、具体的には８００℃（好ましくは８２０℃）以上８８０℃以下で加熱する（低温焼結）。また、焼結雰囲気は、炭素を含有しないガス雰囲気（水素ガス、窒素ガス、アルゴンガス等）あるいは真空とする。このような焼結条件であれば、原料粉末で炭素と鉄の反応が生じず、従って、焼結後の鉄組織は全て軟質のフェライト相（ＨＶ２００以下）となる。原料粉末に流体潤滑剤等の各種成形潤滑剤を含めていた場合、成形潤滑剤は、焼結に伴って揮散する。 From the above viewpoint, the green compact 4 ′ is heated at 900 ° C. or lower, specifically 800 ° C. (preferably 820 ° C.) or higher and 880 ° C. or lower (low temperature sintering). The sintering atmosphere is a gas atmosphere containing no carbon (hydrogen gas, nitrogen gas, argon gas, etc.) or a vacuum. Under such sintering conditions, the reaction between carbon and iron does not occur in the raw material powder, and therefore the iron structure after sintering becomes a soft ferrite phase (HV200 or less). In the case where various molding lubricants such as a fluid lubricant are included in the raw material powder, the molding lubricant volatilizes with sintering.
鉄組織は、その全てをフェライト相（αＦｅ）で形成する他、図７に示すように、フェライト相αＦｅとパーライト相γＦｅの二相組織にすることもできる。これにより、フェライト相αＦｅよりも硬質のパーライト相γＦｅが軸受面の耐摩耗性向上に寄与し、高面圧下での軸受面の摩耗を抑制して軸受寿命を向上させることができる。但し、パーライト相γＦｅの存在割合が過剰となり、フェライト相αＦｅと同等の割合になると、パーライトによる軸３に対する攻撃性が増して軸３が摩耗しやすくなる。これを防止するため、図７に示すように、パーライト相γＦｅはフェライト相αＦｅの粒界に存在（点在）する程度に抑える。ここでいう「粒界」は、粉末粒子間に形成される粒界の他、粉末粒子中に形成される結晶粒界の双方を意味する。鉄組織をフェライト相αＦｅとパーライト相γＦｅの二相組織で形成する場合、鉄組織に占めるフェライト相αＦｅおよびパーライト相γＦｅの割合は、焼結体の任意断面における面積比で、それぞれ、８０〜９５％および５〜２０％（αＦｅ：γＦｅ＝８０〜９５％：５〜２０％）程度とするのが望ましい。これにより、軸３の摩耗抑制と軸受面４ａの耐摩耗性向上とを両立させることができる。 In addition to forming the entire iron structure with a ferrite phase (αFe), as shown in FIG. 7, the iron structure can also be a two-phase structure of a ferrite phase αFe and a pearlite phase γFe. Thereby, the pearlite phase γFe harder than the ferrite phase αFe contributes to the improvement of the wear resistance of the bearing surface, and the wear of the bearing surface under high surface pressure can be suppressed to improve the bearing life. However, if the pearlite phase γFe is present in an excessive proportion and becomes equal to the ferrite phase αFe, the aggressiveness of the pearlite against the shaft 3 increases and the shaft 3 is likely to wear. In order to prevent this, as shown in FIG. 7, the pearlite phase γFe is suppressed to the extent that it exists (is scattered) at the grain boundary of the ferrite phase αFe. The term “grain boundary” as used herein means both a grain boundary formed between powder particles and a crystal grain boundary formed in the powder particle. When the iron structure is formed of a two-phase structure of a ferrite phase αFe and a pearlite phase γFe, the ratio of the ferrite phase αFe and the pearlite phase γFe in the iron structure is an area ratio in an arbitrary cross section of the sintered body. % And 5 to 20% (αFe: γFe = 80 to 95%: 5 to 20%) are desirable. As a result, it is possible to achieve both suppression of wear of the shaft 3 and improvement of wear resistance of the bearing surface 4a.
パーライト相γＦｅの析出量は、主に焼結温度と雰囲気ガスに依存する。従って、上記の態様でパーライト相γＦｅをフェライト相αＦｅの粒界に存在させるためには、焼結温度を８２０℃〜９００℃程度に上げ、かつ炉内雰囲気として炭素を含むガス、例えば天然ガスや吸熱型ガス（ＲＸガス）を用いて焼結する。これにより、焼結時にはガスに含まれる炭素が鉄に拡散し、パーライト相γＦｅを形成することができる。なお、上記のとおり、９００℃を超える温度で圧粉体４’を焼結すると、黒鉛粉中の炭素が鉄と反応してパーライト相γＦｅが形成されるので、圧粉体４’は９００℃以下で焼結するのが好ましい。 The precipitation amount of the pearlite phase γFe mainly depends on the sintering temperature and the atmospheric gas. Therefore, in order to allow the pearlite phase γFe to exist at the grain boundary of the ferrite phase αFe in the above-described manner, the sintering temperature is raised to about 820 ° C. to 900 ° C., and the gas containing carbon as the furnace atmosphere, such as natural gas, Sintering is performed using an endothermic gas (RX gas). As a result, carbon contained in the gas diffuses into iron during sintering, and pearlite phase γFe can be formed. As described above, when the green compact 4 ′ is sintered at a temperature exceeding 900 ° C., carbon in the graphite powder reacts with iron to form a pearlite phase γFe. Sintering is preferred below.
焼結後、焼結体４’’にサイジングを施し、焼結体４’’を仕上がり形状・寸法に仕上げた後、この焼結体４’’の内部気孔に真空含浸等の手法で潤滑油を含浸させると、図１に示す焼結軸受４が完成する。焼結体４’’の内部気孔に含浸させる潤滑油は低粘度のもの、具体的には４０℃の動粘度が１０〜５０ｍｍ2／ｓのもの（例えば合成炭化水素系潤滑油）が使用される。軸受隙間に形成される油膜の剛性を確保しつつ、回転トルクの上昇を抑えるためである。なお、焼結体４"の内部気孔には、４０℃の動粘度が１０〜５０ｍｍ2／ｓの潤滑油を基油としたグリースを含浸させても良い。また、サイジングは必要に応じて施せば足り、必ずしも施す必要はない。また、用途によっては潤滑油の含浸工程を省略し、無給油下で使用する焼結軸受とすることもできる。 After sintering, sizing the sintered body 4 ″, finishing the sintered body 4 ″ into a finished shape and size, and then lubricating the internal pores of the sintered body 4 ″ with a technique such as vacuum impregnation. 1 is completed, the sintered bearing 4 shown in FIG. 1 is completed. The lubricating oil impregnated in the internal pores of the sintered body 4 ″ has a low viscosity, specifically, a kinematic viscosity at 40 ° C. of 10 to 50 mm 2 / s (for example, a synthetic hydrocarbon-based lubricating oil) is used. The This is to suppress the increase in rotational torque while ensuring the rigidity of the oil film formed in the bearing gap. The internal pores of the sintered body 4 ″ may be impregnated with grease based on a lubricating oil having a kinematic viscosity at 40 ° C. of 10 to 50 mm 2 / s. Sizing may be performed as necessary. In addition, depending on the application, the step of impregnating the lubricating oil can be omitted, and a sintered bearing used without oil supply can be obtained.
圧粉体４’の焼結温度を銅の融点（１０８３℃）よりも遥かに低温の９００℃以下とした上記の焼結条件であれば、圧粉体４’に含まれる（部分拡散合金粉１１を構成する）銅粉１３は溶融せず、従って、焼結に伴って銅が鉄（鉄組織）中に拡散しない。そのため、この焼結体４’’の表面（軸受面４ａ）には適量の銅組織が形成されている。また、焼結体４’’の表面には遊離黒鉛も露出している。そのため、軸３との初期なじみ性が良好で、軸受面４ａの摩擦係数も小さい焼結軸受４を得ることができる。 If the sintering conditions of the green compact 4 ′ are 900 ° C. or lower, which is much lower than the melting point of copper (1083 ° C.), the green compact 4 ′ is included (partial diffusion alloy powder). 11) does not melt, and therefore copper does not diffuse into the iron (iron structure) during sintering. For this reason, an appropriate amount of copper structure is formed on the surface (bearing surface 4a) of the sintered body 4 ''. Further, free graphite is also exposed on the surface of the sintered body 4 ″. Therefore, it is possible to obtain the sintered bearing 4 having good initial conformability with the shaft 3 and having a small friction coefficient of the bearing surface 4a.
焼結体４’’には、鉄を主成分とする鉄組織および銅を主成分とする銅組織が形成される。焼結体４’’の鉄組織および銅組織の多くは部分拡散合金粉１１で形成されるが、部分拡散合金粉では、銅粉の一部が鉄粉に拡散しているため、焼結後の鉄組織と銅組織の間で高いネック強度を得ることができる。また、焼結時には、圧粉体４’中の錫粉１４は溶融し、部分拡散合金粉１１を構成する銅粉１３の表面を濡らす。これに伴い、錫（Ｓｎ）と銅（Ｃｕ）との間で液相焼結が進行し、図７に示すように、隣り合う部分拡散合金粉１１の鉄組織と銅組織、あるいは銅組織同士を結合する青銅相（Ｃｕ−Ｓｎ）１６が形成される。また、個々の部分拡散合金粉１１のうち、鉄粉１２の表面に銅粉１３の一部が拡散してＦｅ−Ｃｕ合金が形成された部分には、溶融したＳｎが拡散してＦｅ−Ｃｕ−Ｓｎ合金（合金相）１７が形成されるため、鉄組織と銅組織の間のネック強度が一層高くなる。そのため、上述したような低温焼結でも高い圧環強度、具体的には３００ＭＰａ以上の圧環強度を得ることができる。また、軸受面４ａを硬くして軸受面４ａの耐摩耗性を向上させることもできる。なお、図７においては、フェライト相αＦｅやパーライト相γＦｅなどを色の濃淡で表現している。具体的には、フェライト相αＦｅ→青銅相１６→Ｆｅ−Ｃｕ−Ｓｎ合金（合金相）１７→パーライト相γＦｅの順に色を濃くしている。 In the sintered body 4 ″, an iron structure mainly composed of iron and a copper structure mainly composed of copper are formed. Most of the iron structure and copper structure of the sintered body 4 ″ are formed of the partial diffusion alloy powder 11. However, in the partial diffusion alloy powder, since a part of the copper powder is diffused into the iron powder, A high neck strength can be obtained between the iron structure and the copper structure. Further, at the time of sintering, the tin powder 14 in the green compact 4 ′ is melted and wets the surface of the copper powder 13 constituting the partial diffusion alloy powder 11. Along with this, liquid phase sintering proceeds between tin (Sn) and copper (Cu), and as shown in FIG. 7, the iron structure and copper structure of adjacent partial diffusion alloy powders 11 or between copper structures A bronze phase (Cu—Sn) 16 is formed. In addition, among the individual partial diffusion alloy powders 11, molten Sn is diffused and Fe—Cu is diffused in a part where a part of the copper powder 13 is diffused on the surface of the iron powder 12 to form an Fe—Cu alloy. Since the -Sn alloy (alloy phase) 17 is formed, the neck strength between the iron structure and the copper structure is further increased. Therefore, a high crushing strength, specifically, a crushing strength of 300 MPa or more can be obtained even at the low temperature sintering as described above. Further, the bearing surface 4a can be hardened to improve the wear resistance of the bearing surface 4a. In FIG. 7, the ferrite phase αFe, the pearlite phase γFe, and the like are represented by shades of color. Specifically, the colors are darkened in the order of ferrite phase αFe → bronze phase 16 → Fe—Cu—Sn alloy (alloy phase) 17 → pearlite phase γFe.
また、本願発明では、原料粉末に単体鉄粉や単体銅粉からなる添加粉を配合している。従って、単体鉄粉や単体銅粉の配合量を変更することにより、部分拡散合金粉を使用することで得られる耐摩耗性、高強度、および良好な摺動特性を維持しつつ、軸受特性を調整することが可能となる。例えば添加粉として単体鉄粉を使用すれば、軸受の耐摩耗性や強度をさらに高めることができ、添加粉として単体銅粉を使用すれば摺動特性をさらに改善することができる。そのため、各用途に適合した焼結軸受の開発コストを低廉化することができ、焼結軸受の多品種少量生産にも対応可能となる。例えば部分拡散合金粉における銅粉の拡散量は３０質量％程度が限界となるので、部分拡散合金粉だけで銅組織を形成すると、軸受中における銅の割合をそれ以上多くすることが困難となる。これに対し、添加粉として単体銅粉を配合することで、軸受中における銅の割合を３０質量％よりも大きくすることができる。 Moreover, in this invention, the additive powder which consists of a simple iron powder and a simple copper powder is mix | blended with raw material powder. Therefore, by changing the blending amount of single iron powder and single copper powder, bearing characteristics are maintained while maintaining the wear resistance, high strength, and good sliding characteristics obtained by using the partial diffusion alloy powder. It becomes possible to adjust. For example, if a single iron powder is used as the additive powder, the wear resistance and strength of the bearing can be further increased, and if a single copper powder is used as the additive powder, the sliding characteristics can be further improved. Therefore, it is possible to reduce the development cost of the sintered bearing suitable for each application, and it is possible to cope with the production of various types of sintered bearings in small quantities. For example, the diffusion amount of the copper powder in the partial diffusion alloy powder is limited to about 30% by mass. Therefore, when the copper structure is formed only with the partial diffusion alloy powder, it becomes difficult to increase the ratio of copper in the bearing further. . On the other hand, the ratio of the copper in a bearing can be made larger than 30 mass% by mix | blending single-piece | unit copper powder as an additional powder.
原料粉末における部分拡散合金粉の配合割合が少なすぎると、部分拡散合金粉を使用したことによるメリットが減殺され、耐摩耗性、強度、および摺動特性を満足することが困難となる。従って、原料粉末における部分拡散合金粉の配合割合は、５０質量％以上（望ましくは７５質量％以上）とするのが好ましい。また、固体潤滑剤粉は、これが少なすぎると摺動特性を害し、多すぎると圧環強度の低下を招くので、原料粉末中の配合割合は０．３〜１．５質量％とする。低融点金属粉は、これが少ないと液相焼結の進行が不十分となるために強度低下を招き、これが多いと焼結体４"の機械的強度が高まるものの粗大気
孔が増える問題がある。従って、低融点金属粉の配合割合は、原料粉末中における銅粉の総質量（部分拡散合金粉中の銅粉と添加粉として添加した単体銅粉の和）の１０質量％程度にするのが好ましい。具体的には、原料粉末における低融点金属の配合割合を０．５〜５．０質量％に設定する。原料粉末の残部は添加粉および不可避的不純物からなる。添加粉の配合割合は、これを配合することによるメリットを考えれば、少なくも原料粉末の１．０質量％以上配合するのが好ましい。
If the blending ratio of the partial diffusion alloy powder in the raw material powder is too small, the merit of using the partial diffusion alloy powder is diminished, and it becomes difficult to satisfy the wear resistance, strength, and sliding characteristics. Therefore, the blending ratio of the partial diffusion alloy powder in the raw material powder is preferably 50% by mass or more (desirably 75% by mass or more). Further, if the amount of the solid lubricant powder is too small, the sliding characteristics are impaired. If the amount is too large, the crushing strength is reduced. Therefore, the blending ratio in the raw material powder is set to 0.3 to 1.5 mass%. If the amount of the low melting point metal powder is small, the progress of the liquid phase sintering becomes insufficient, and therefore the strength is lowered. Therefore, the blending ratio of the low melting point metal powder should be about 10% by mass of the total mass of the copper powder in the raw material powder (the sum of the copper powder in the partial diffusion alloy powder and the single copper powder added as the additive powder). Specifically, the blending ratio of the low melting point metal in the raw material powder is set to 0.5 to 5.0 mass%, and the balance of the raw material powder is composed of additive powder and inevitable impurities. Considering the merit of blending this, it is preferable to blend at least 1.0 mass% of the raw material powder.
なお、軸受面４ａに必要とされる摺動特性を満足するため、焼結軸受４における銅の割合は少なくとも１０質量％以上（好ましくは１５質量％以上）とする。 In order to satisfy the sliding characteristics required for the bearing surface 4a, the ratio of copper in the sintered bearing 4 is at least 10% by mass (preferably 15% by mass or more).
また、部分拡散合金粉１１として、平均粒度１４５メッシュ以下（平均粒径１０６μｍ以下）の粉末を使用することにより、焼結体４’’の多孔質組織を均一化して粗大気孔の生成を防止することができる。そのため、焼結体４’’を高密度化して圧環強度や軸受面４ａの耐摩耗性をさらに高めることができる。 Further, by using a powder having an average particle size of 145 mesh or less (average particle size of 106 μm or less) as the partial diffusion alloy powder 11, the porous structure of the sintered body 4 ″ is made uniform to prevent the formation of rough atmospheric pores. be able to. Therefore, the density of the sintered body 4 ″ can be increased to further improve the crushing strength and the wear resistance of the bearing surface 4 a.
以上に示すように、本実施形態の焼結体４’’は３００ＭＰａ以上の圧環強度を有しており、この圧環強度の値は、既存の銅鉄系焼結体のそれに比べて２倍以上の値である。また、本実施形態の焼結体４’’の密度は６．８±０．３ｇ／ｃｍ3となり、既存の鉄銅系焼結体の密度（６．６ｇ／ｃｍ3程度）よりも高密度となる。既存の鉄銅系焼結体でも圧粉体の成形工程で高圧縮することで高密度化することは可能であるが、このようにすると、内部の流体潤滑剤が焼結時に燃焼できずにガス化するため、表層部の気孔が粗大化してしまう。本発明では圧粉体の成形時に高圧縮する必要はなく、そのような不具合を防止することができる。 As described above, the sintered body 4 ″ of the present embodiment has a crushing strength of 300 MPa or more, and the value of the crushing strength is twice or more that of the existing copper iron-based sintered body. Is the value of In addition, the density of the sintered body 4 ″ of this embodiment is 6.8 ± 0.3 g / cm 3 , which is higher than the density of the existing iron-copper-based sintered body (about 6.6 g / cm 3 ). It becomes. Even existing iron-copper-based sintered bodies can be densified by high compression in the green compact molding process, but this will prevent the internal fluid lubricant from burning during sintering. Because of gasification, the pores in the surface layer portion become coarse. In the present invention, it is not necessary to perform high compression at the time of forming the green compact, and such a problem can be prevented.
このように焼結体４’’を高密度化させる一方で、含油率を１５ｖｏｌ％以上にすることができ、既存の鉄銅系焼結軸受と同程度の含油率を確保できる。これは、主に部分拡散合金粉１１を構成する鉄粉１２として、海綿状をなし、保油性に優れた還元鉄粉を使用していることに由来する。この場合、焼結体４’’に含浸させた潤滑油は、焼結組織の粒子間に形成された気孔だけでなく、還元鉄粉（部分拡散合金粉を構成する還元鉄粉の他、添加粉として還元鉄粉を使用した場合には当該還元鉄粉も含まれる）が有する気孔にも保持される。 Thus, while densifying the sintered body 4 ″, the oil content can be increased to 15 vol% or more, and an oil content comparable to that of an existing iron-copper sintered bearing can be secured. This is mainly due to the use of reduced iron powder having a spongy shape and excellent oil retention as the iron powder 12 constituting the partial diffusion alloy powder 11. In this case, the lubricating oil impregnated in the sintered body 4 ″ is added not only to the pores formed between the particles of the sintered structure, but also to the reduced iron powder (in addition to the reduced iron powder constituting the partial diffusion alloy powder) When reduced iron powder is used as the powder, the reduced iron powder is also contained).
粗大気孔は特に焼結体４’’の表層部（焼結体表面から深さ１００μｍに至るまでの領域）で生じやすいが、以上のようにして得られた焼結体４’’であれば、上記のように表層部における粗大気孔の発生を防止して表層部の高密度化を図ることができる。具体的には、表層部の気孔率を、５〜２０％にすることができる。この気孔率は、例えば焼結体４’’の任意断面における気孔部の面積比率を画像解析することで求めることができる。 Rough atmospheric holes are likely to occur especially in the surface layer portion of the sintered body 4 ″ (region from the sintered body surface to a depth of 100 μm), but if the sintered body 4 ″ obtained as described above is used, As described above, it is possible to prevent the formation of rough air holes in the surface layer portion and to increase the density of the surface layer portion. Specifically, the porosity of the surface layer portion can be 5 to 20%. This porosity can be obtained, for example, by image analysis of the area ratio of the pores in an arbitrary cross section of the sintered body 4 ″.
このように表層部が高密度化されることで軸受面４ａの表面開孔率も小さくなり、具体的には、軸受面４ａの表面開孔率を５％以上２０％以下の範囲内に設定することができる。なお、表面開孔率が５％を下回ると、軸受隙間に必要十分量の潤滑油を滲み出させることが難しくなり（油膜形成能力が不十分となり）、焼結軸受としてのメリットを得ることができない。 By increasing the density of the surface layer portion in this way, the surface aperture ratio of the bearing surface 4a is also reduced. Specifically, the surface aperture ratio of the bearing surface 4a is set within a range of 5% to 20%. can do. When the surface area ratio is less than 5%, it becomes difficult to exude a necessary and sufficient amount of lubricating oil into the bearing gap (insufficient oil film forming ability), and a merit as a sintered bearing can be obtained. Can not.
また、この焼結体４’’を得るための原料粉末として、鉄粉１２の表面に銅粉１３を部分拡散させた部分拡散合金粉１１を主原料としたものを使用しているため、既存の鉄銅系焼結軸受で問題となる銅の偏析を防止することができる。また、この焼結体４’’であれば、ＮｉやＭｏ等の高価な金属粉末を使用することなく機械的強度を向上させることができるので、焼結軸受４の低コスト化も達成される。 In addition, as the raw material powder for obtaining this sintered body 4 '', since the main raw material is partially diffused alloy powder 11 in which copper powder 13 is partially diffused on the surface of iron powder 12, the existing powder is used. It is possible to prevent copper segregation which is a problem in the iron-copper sintered bearings. Further, with this sintered body 4 ″, the mechanical strength can be improved without using expensive metal powders such as Ni and Mo, so that the cost of the sintered bearing 4 can be reduced. .
以上で説明したように、本発明に係る焼結軸受４は高い圧環強度（３００ＭＰａ以上の圧環強度）を有するため、図１に示すようにハウジング２の内周に圧入固定した場合でも、軸受面４ａがハウジング２の内周面形状に倣って変形することがなく、取り付け後も軸受面４ａの真円度や円筒度等を安定的に維持することができる。そのため、ハウジング２の内周に焼結軸受４を圧入固定した後、軸受面４ａを適正形状・精度に仕上げるための加工（例えばサイジング）を追加的に実行することなく、所望の真円度（例えば３μｍ以下の真円度）を確保することができる。また、焼結軸受４が３００ＭＰａ以上の圧環強度を有していれば、この焼結軸受４を組み込んだ振動モータ１（ひいてはこの振動モータ１を備えた携帯端末等）が落下等することにより軸受面４ａに大きな衝撃加重が付加された場合でも、軸受面４ａの変形が可及的に防止される。さらに、軸受面４ａが高硬度化されて高い耐摩耗性を有するため、たとえ軸受面４ａの全面を軸３が振れ回り、あるいは軸３が軸受面４ａに頻繁に衝突したとしても、軸受面４ａの摩耗や損傷が抑えられる。従って、本発明によれば、振動モータの支持に適合した焼結軸受４を低コストに提供することができる。 As described above, since the sintered bearing 4 according to the present invention has a high crushing strength (crushing strength of 300 MPa or more), even when press-fitted and fixed to the inner periphery of the housing 2 as shown in FIG. 4a does not deform following the shape of the inner peripheral surface of the housing 2, and the roundness and cylindricity of the bearing surface 4a can be stably maintained even after the mounting. Therefore, after press-fitting and fixing the sintered bearing 4 to the inner periphery of the housing 2, a desired roundness (for example, sizing) is additionally performed without finishing processing (for example, sizing) for finishing the bearing surface 4a to an appropriate shape and accuracy. For example, a roundness of 3 μm or less can be ensured. Further, if the sintered bearing 4 has a crushing strength of 300 MPa or more, the vibration motor 1 incorporating the sintered bearing 4 (and thus a portable terminal equipped with the vibration motor 1) may drop and the like. Even when a large impact load is applied to the surface 4a, deformation of the bearing surface 4a is prevented as much as possible. Furthermore, since the bearing surface 4a is hardened and has high wear resistance, even if the shaft 3 swings around the entire surface of the bearing surface 4a or the shaft 3 frequently collides with the bearing surface 4a, the bearing surface 4a. Wear and damage can be suppressed. Therefore, according to the present invention, the sintered bearing 4 suitable for supporting the vibration motor can be provided at low cost.
ここで、参考までに、特許文献１に記載の技術手段に係る焼結軸受（以下、「銅被覆鉄粉軸受」という）の表層部の顕微鏡写真を図８に示す。図８と、本実施形態に係る焼結軸受４の表層部の顕微鏡写真（図３参照）とを比較すると、本実施形態に係る焼結軸受４は、銅被覆鉄粉軸受に比べて表層部の多孔質組織が均一化され、緻密であることが理解される。実際、本実施形態に係る焼結軸受４の表層部の気孔率は、１３．６％だったのに対し、銅被覆鉄粉軸受の表層部の気孔率は、２５．５％程度であった。このような差を生じた要因として、銅被覆鉄粉では鉄粉に銅膜が密着しているにすぎず、鉄相と銅相の間のネック強度が不足していることが挙げられる。 Here, for reference, a micrograph of a surface layer portion of a sintered bearing (hereinafter referred to as “copper-coated iron powder bearing”) according to the technical means described in Patent Document 1 is shown in FIG. Comparing FIG. 8 with a micrograph (see FIG. 3) of the surface layer portion of the sintered bearing 4 according to the present embodiment, the sintered bearing 4 according to the present embodiment has a surface layer portion as compared with the copper-coated iron powder bearing. It is understood that the porous structure is uniform and dense. Actually, the porosity of the surface layer portion of the sintered bearing 4 according to the present embodiment was 13.6%, whereas the porosity of the surface layer portion of the copper-coated iron powder bearing was about 25.5%. . As a factor causing such a difference, in the copper-coated iron powder, only the copper film is in close contact with the iron powder, and the neck strength between the iron phase and the copper phase is insufficient.
以上、本発明の一実施形態に係る焼結軸受について説明を行ったが、本発明の実施の形態は上述のものに限られない。 As mentioned above, although the sintered bearing which concerns on one Embodiment of this invention was demonstrated, embodiment of this invention is not restricted to the above-mentioned thing.
例えば、圧粉体４’を圧縮成形する際には、成形金型２０および原料粉末１０の少なくとも一方を加熱した状態で圧粉体４’を圧縮成形する、いわゆる温間成形法や、成形金型２０の成形面（キャビティ２５の画成面）に潤滑剤を塗布した状態で圧粉体４’を圧縮成形する金型潤滑成形法を採用しても良い。このような方法を採用すれば、圧粉体４’を一層精度良く成形することができる。 For example, when the green compact 4 ′ is compression-molded, a so-called warm molding method in which at least one of the molding die 20 and the raw material powder 10 is heated and the green compact 4 ′ is compression-molded, A die lubrication molding method may be employed in which the green compact 4 ′ is compression molded in a state where a lubricant is applied to the molding surface of the mold 20 (the defined surface of the cavity 25). By adopting such a method, the green compact 4 ′ can be molded with higher accuracy.
また、本発明に係る焼結軸受４は、振動モータに限らず、モータの主軸支持用途をはじめ、軸を回転自在に支持する軸受として広く使用することができる。本実施形態では、軸３を回転させる場合を説明したが、これとは逆に軸受４を回転させる用途にも使用することができる。また、焼結軸受４の軸受面４ａには、動圧溝等の動圧発生部を設けることもできる。このようにすれば、軸受隙間に形成される油膜の剛性を高めることができるので回転精度を一層高めることができる。 Further, the sintered bearing 4 according to the present invention is not limited to a vibration motor, but can be widely used as a bearing that rotatably supports a shaft including a main shaft support application of a motor. In the present embodiment, the case where the shaft 3 is rotated has been described, but it can also be used for the purpose of rotating the bearing 4 on the contrary. Further, the bearing surface 4 a of the sintered bearing 4 can be provided with a dynamic pressure generating portion such as a dynamic pressure groove. In this way, since the rigidity of the oil film formed in the bearing gap can be increased, the rotational accuracy can be further increased.
１ 振動モータ
２ ハウジング
３ 軸
４ 焼結軸受
４’ 圧粉体
４’’ 焼結体
４ａ 軸受面
１０ 原料粉末
１１ 部分拡散合金粉
１２ 鉄粉
１３ 銅粉
１４ 錫粉（低融点金属粉）
１６ 青銅相
１７ Ｆｅ−Ｃｕ−Ｓｎ合金
２０ 成形金型
αＦｅ フェライト相
γＦｅ パーライト相
Ｍ モータ部
Ｗ 錘
DESCRIPTION OF SYMBOLS 1 Vibration motor 2 Housing 3 Shaft 4 Sintered bearing 4 'Green compact 4''Sintered body 4a Bearing surface 10 Raw material powder 11 Partially diffused alloy powder 12 Iron powder 13 Copper powder 14 Tin powder (low melting metal powder)
16 Bronze phase 17 Fe-Cu-Sn alloy 20 Molding die αFe Ferrite phase γFe Pearlite phase M Motor part W Weight
Claims (11)
平均粒径５μｍ以上２０μｍ未満の銅粉が鉄粉に部分拡散し、かつＣｕを１０〜３０質量％含有する部分拡散合金粉と、低融点金属粉と、固体潤滑剤粉と、単体鉄粉および単体銅粉のどちらか一方もしくは双方からなる添加粉とを含む原料粉末を成形し、焼結した焼結体からなる焼結軸受。 A sintered bearing having a bearing surface on the inner periphery that forms a bearing gap with a shaft to be supported,
Copper powder having an average particle size of 5 μm or more and less than 20 μm is partially diffused into iron powder, and partially diffused alloy powder containing 10 to 30% by mass of Cu, low melting point metal powder, solid lubricant powder, simple iron powder, and A sintered bearing made of a sintered body obtained by forming and sintering a raw material powder containing additive powder composed of either or both of simple copper powders.
鉄粉に銅粉を部分拡散させてなる平均粒度１４５メッシュ以下の部分拡散合金粉と、低融点金属粉と、固体潤滑剤粉と、単体鉄粉および単体銅粉のどちらか一方もしくは双方からなる添加粉とを含む原料粉末を成形し、焼結した焼結体からなる焼結軸受。 A sintered bearing having a bearing surface on the inner periphery that forms a bearing gap with a shaft to be supported,
It consists of one or both of partial diffusion alloy powder having an average particle size of 145 mesh or less, low melting point metal powder, solid lubricant powder, and single iron powder and single copper powder. A sintered bearing made of a sintered body obtained by molding and sintering raw material powder containing additive powder.
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02145703A (en) * | 1988-11-26 | 1990-06-05 | Kobe Steel Ltd | High strength alloy steel powder for powder metallurgy |
| JPH0995759A (en) * | 1995-09-29 | 1997-04-08 | Heiwa Sangyo Kk | Oil-impregnated sintered bearing and its production |
| JPH11336761A (en) * | 1998-05-28 | 1999-12-07 | Ntn Corp | Dynamic pressure type sintered grease-impregnated bearing |
| JP2003313624A (en) * | 2002-02-20 | 2003-11-06 | Jfe Steel Kk | Method for manufacturing iron-base sintered compact |
| JP2004292861A (en) * | 2003-03-26 | 2004-10-21 | Jfe Steel Kk | Iron-based powdery mixture for powder metallurgy, and its production method |
| JP2005179571A (en) * | 2003-12-22 | 2005-07-07 | Matsushita Electric Ind Co Ltd | Impregnation bearing oil and bearing impregnated therewith |
| WO2014010429A1 (en) * | 2012-07-10 | 2014-01-16 | ナパック株式会社 | Method for manufacturing thrust bearing for turbocharger, and thrust bearing for turbocharger |
-
2018
- 2018-03-02 JP JP2018037378A patent/JP6571230B2/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02145703A (en) * | 1988-11-26 | 1990-06-05 | Kobe Steel Ltd | High strength alloy steel powder for powder metallurgy |
| JPH0995759A (en) * | 1995-09-29 | 1997-04-08 | Heiwa Sangyo Kk | Oil-impregnated sintered bearing and its production |
| JPH11336761A (en) * | 1998-05-28 | 1999-12-07 | Ntn Corp | Dynamic pressure type sintered grease-impregnated bearing |
| JP2003313624A (en) * | 2002-02-20 | 2003-11-06 | Jfe Steel Kk | Method for manufacturing iron-base sintered compact |
| JP2004292861A (en) * | 2003-03-26 | 2004-10-21 | Jfe Steel Kk | Iron-based powdery mixture for powder metallurgy, and its production method |
| JP2005179571A (en) * | 2003-12-22 | 2005-07-07 | Matsushita Electric Ind Co Ltd | Impregnation bearing oil and bearing impregnated therewith |
| WO2014010429A1 (en) * | 2012-07-10 | 2014-01-16 | ナパック株式会社 | Method for manufacturing thrust bearing for turbocharger, and thrust bearing for turbocharger |
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