WO2018100660A1 - Ferrous sinter oil-containing bearing - Google Patents

Ferrous sinter oil-containing bearing Download PDF

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Publication number
WO2018100660A1
WO2018100660A1 PCT/JP2016/085507 JP2016085507W WO2018100660A1 WO 2018100660 A1 WO2018100660 A1 WO 2018100660A1 JP 2016085507 W JP2016085507 W JP 2016085507W WO 2018100660 A1 WO2018100660 A1 WO 2018100660A1
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Prior art keywords
iron
based sintered
bearing
phase
dispersed
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PCT/JP2016/085507
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French (fr)
Japanese (ja)
Inventor
亮一 宮崎
英昭 河田
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日立化成株式会社
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Priority to JP2018553563A priority Critical patent/JP6819696B2/en
Priority to PCT/JP2016/085507 priority patent/WO2018100660A1/en
Publication of WO2018100660A1 publication Critical patent/WO2018100660A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F5/00—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C33/00—Making ferrous alloys
    • C22C33/02—Making ferrous alloys by powder metallurgy
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
    • F16C33/02—Parts of sliding-contact bearings
    • F16C33/04—Brasses; Bushes; Linings
    • F16C33/06—Sliding surface mainly made of metal
    • F16C33/10—Construction relative to lubrication

Definitions

  • the present invention relates to an iron-based sintered oil-impregnated bearing having a bearing surface that supports the outer peripheral surface of a shaft.
  • Sintered oil-impregnated bearings are a sintered bearing made of a sintered alloy having pores, the pores of which are impregnated with lubricating oil, and can provide self-lubricating properties due to the impregnated lubricating oil. Is good and widely used.
  • a sintered body constituting the sintered bearing 1 which is a main body of the sintered oil-impregnated bearing is a porous body in which pores are dispersed in a metal matrix, and the lubricant 2 is impregnated in the pores.
  • the sintered bearing is formed in a substantially circular tube or a substantially annular ring, and supports the shaft 3 on its inner peripheral surface.
  • the lubricating oil impregnated in the pores is thermally expanded due to frictional heat with the shaft, and the lubricating oil impregnated in the pores is sucked out by the rotation of the shaft.
  • the lubricating oil flows from the upper part of the low oil pressure toward the sliding part that receives the high oil pressure.
  • the shaft is lifted from the inner peripheral surface of the bearing by the flow of the lubricating oil to prevent metal contact between the inner peripheral surface of the bearing and the shaft.
  • the flow of lubricating oil entering between the shaft and the inner peripheral surface of the bearing causes the shaft to be shifted in the rotational direction, and the hydraulic pressure distribution 5 on the inner peripheral surface of the bearing is as shown in FIG.
  • the lubricating oil escapes through the pores even when hydraulic pressure is generated, the lubricating oil circulates through the pores in the sintered bearing and exhibits an effective lubricating action on the inner peripheral surface again.
  • the shaft supported by the bearing is generally made of an inexpensive iron alloy, and a copper-based sintered bearing to which a copper-based sintered alloy is applied has been frequently used as the sintered bearing.
  • a copper-based sintered bearing to which a copper-based sintered alloy is applied has been frequently used as the sintered bearing.
  • the need for an iron-based sintered bearing using an iron-based sintered alloy whose main component is inexpensive iron is increasing.
  • there are disadvantages that it is easy to seize and the shaft which is a counterpart part is easily damaged.
  • the above phenomenon becomes prominent when a low-hardness shaft that has not been heat-treated and a bearing mainly composed of iron are used in combination.
  • Patent Document 1 has excellent wear resistance, seizure resistance comparable to iron-copper sintered bearings using iron-copper-based sintered alloys, and attack mitigation to counterpart parts.
  • Iron-based sintered bearings have been proposed as having the above.
  • the total composition of the sintered alloy is, by mass ratio, Cu: 2.0 to 9.0%, C: 1.5 to 3.7%, the balance: Fe and inevitable impurities.
  • the copper phase is exposed on the bearing surface at an area ratio of 8 to 40%.
  • the overall composition has a mass ratio of C: 0.6 to 1.2%, Cu: 3.5 to 9.0%, Mn: 0.6 to 2.2%, S: 0.4 to 1.3%, balance: Fe-based sintered alloy for sliding members comprising Fe and inevitable impurities Has been proposed (Patent Document 2), and the alloy structure is such that at least one of the free Cu phase and the free Cu—Fe alloy phase is dispersed in the martensite matrix, and the MnS phase is 1.0. It is characterized by being dispersed by 3.5% by mass.
  • the lubricating oil drawn from the pores by the rotation of the shaft is drawn between the shaft and the inner peripheral surface of the bearing as the shaft rotates, and between the shaft and the inner peripheral surface of the bearing.
  • the application to various uses is progressing, but the application is not progressing for uses that are difficult to form a good oil film.
  • further improvement of the sintered bearing is necessary.
  • Fields in which such sintered oil-impregnated bearings have been considered difficult to apply include, for example, supporting forward and reverse rotating shafts such as paper feed rollers for copiers, head drive motors, etc.
  • bearings for applications where the driving time for each rotation and reverse rotation is short are bearings for applications where the driving time for each rotation and reverse rotation is short. In such an application, as shown in FIG. 2A, the rotation stops before a good lubricating oil film is formed, and therefore metal contact between the shaft and the inner peripheral surface of the bearing is likely to occur.
  • the iron-based sintered bearing of Patent Document 1 has excellent wear resistance for applications in which a good lubricating oil film can be formed, and has seizure resistance comparable to that of an iron-copper-based sintered oil-impregnated bearing. Has mitigation against attacks on opponent parts. However, further improvements are needed for applications where metal contact is likely to occur.
  • the iron-based sintered sliding member of Patent Document 2 is lubricated by the released Cu phase or Cu—Fe alloy phase and MnS phase, and exhibits sliding characteristics.
  • the MnS phase is formed by leaving the MnS powder added to the raw material powder as it is, the MnS phase is dispersed only at the grain boundaries (powder grain boundaries) between the iron powders.
  • the MnS powder is stable and does not react with other powders, it does not react with the iron powder forming the matrix, and therefore the adhesion to the matrix is poor.
  • the present invention does not depend on the technique of Patent Document 2 with poor adhesion, and further improves the lubrication characteristics for iron-based sintered oil-impregnated bearings, and also has excellent lubrication characteristics even in applications where metal contact is likely to occur. It aims at providing the iron system sintered bearing which shows this, and its manufacturing method.
  • the inventors of the present invention have studied an iron-based sintered bearing that achieves the above object, and depositing and dispersing sulfides in the base of the iron-based sintered alloy constituting the main body of the iron-based sintered bearing, thereby providing a metal contact It has been found that good lubrication characteristics can be exhibited even in applications where the occurrence of such a tendency to occur.
  • an iron-based sintered oil-impregnated bearing has a bearing surface that supports the outer peripheral surface of the shaft, and an iron-based sintered bearing configured of an iron-based sintered alloy in which pores are dispersed;
  • An iron-based sintered oil-impregnated bearing having lubricating oil impregnated in the pores, wherein the total composition of the iron-based sintered alloy is Cu: 0.5 to 3%, C: 1 to 5 %, S: 0.3-2%, balance: Fe and inevitable impurities, the density of the iron-based sintered alloy is 5.2-7.2 g / cm 3 , From a base having one metal structure of a ferrite structure, a pearlite structure, and a mixed structure of ferrite and pearlite, a copper phase and a graphite phase dispersed in the base, and at least one of the base and the copper phase
  • the gist is to have a sulfide phase that precipitates and disperses.
  • the sulfide phase may be precipitated and dispersed within crystal boundaries and crystal grains of the matrix and the copper phase, and the sulfide is mainly composed of iron sulfide and copper sulfide. It's okay.
  • the sulfide phase dispersed in the metal structure is dispersed at an area ratio of 0.9 to 6% with respect to the area of the cross section including pores when the cross section of the metal structure is observed.
  • the sulfide phase is granular and the maximum particle size is preferably 50 ⁇ m or less.
  • the copper phase and the copper sulfide phase dispersed on the bearing surface are dispersed at an area ratio of 5 to 20% with respect to the entire bearing surface.
  • the iron-based sintered bearing is excellently improved in lubrication characteristics and exhibits good lubrication characteristics even in applications where metal contact is likely to occur.
  • the iron-based sintered bearing which is the main body of the iron-based sintered oil-impregnated bearing is composed of an iron-based sintered alloy containing Fe (iron) as a main component.
  • the iron-based sintered alloy includes an iron-based matrix (ferrite phase P1 in FIG. 3), a copper phase P2, a graphite phase P3, and a sulfide phase P4.
  • Fe is a component suitable as a main component of an iron-based sintered alloy because it is cheaper than Cu (copper) and has excellent mechanical strength.
  • Fe is introduced in the form of iron powder, and the base of the iron-based sintered alloy is formed by using the raw material powder mainly composed of iron powder.
  • the pores are dispersed in the base of the iron-based sintered alloy.
  • the pores are caused by the powder metallurgy method, and voids between the powder particles when the raw material powder is compacted are left in the base formed by the bonding of the raw material powders.
  • the base metal structure of the iron-based sintered alloy is one of a ferrite structure, a pearlite structure, and a mixed structure of ferrite and pearlite.
  • Ferrite is soft and has good compatibility with the shaft that is the counterpart material, but has low mechanical strength.
  • pearlite has a high base hardness and a high mechanical strength, but there is a possibility that the shaft that is the counterpart material is worn.
  • the base metal structure of the iron-based sintered alloy depends on the required characteristics of the iron-based sintered bearing, including a ferrite single-phase metal structure, a mixed metal structure of ferrite and pearlite, and a pearlite single-phase metal structure. Either.
  • the density of the sintered alloy (sintered body density) is lower than the theoretical density.
  • the density of the sintered alloy is high, the amount of pores decreases, and when the density of the sintered alloy is low, the amount of pores increases.
  • the pores formed in the iron-based sintered alloy are impregnated with a lubricating oil, thereby exhibiting lubrication characteristics for a long time without lubrication.
  • the amount of pores formed in the iron-based sintered alloy constituting the iron-based sintered bearing is poor, that is, if the density of the iron-based sintered alloy is high, the amount of lubricating oil impregnated becomes small and good. The proper lubrication properties cannot be achieved.
  • the amount of pores formed in the iron-based sintered alloy is excessive, that is, if the density of the iron-based sintered alloy is low, the amount of iron-based sintered alloy base decreases, resulting in the mechanical properties of the iron-based sintered alloy. Strength will decrease. From this viewpoint, the density of the iron-based sintered alloy or equal to 5.2 ⁇ 7.2g / cm 3.
  • the density of the iron-based sintered alloy corresponds to approximately 10 to 25% in terms of the porosity of the iron-based sintered alloy.
  • the density ratio of a sintered compact is measured by the sintering density test method of a metal sintered material prescribed
  • Cu is a component that can form a soft copper phase to improve the compatibility with the mating shaft and improve the lubricity by forming copper sulfide with excellent lubricity. is there.
  • the amount of Cu is poor, the copper phase dispersed in the base becomes poor and the above effect becomes poor.
  • the expensive Cu is excessive, the cost increases accordingly. For this reason, the amount of Cu is 0.5-3 mass%.
  • the copper powder is preferably a flat or foil copper powder.
  • the amount of copper phase exposed on the inner diameter surface of the bearing which requires sliding characteristics, is larger than that in the bearing. Therefore, even if the amount of Cu in the bearing is reduced to reduce the amount of Cu in the entire composition, the amount of the copper phase exposed on the inner diameter surface of the bearing can be maintained at a required amount.
  • the appropriate amount of the total of the copper phase dispersed on the bearing inner surface and the copper sulfide phase described later can be 5 to 20% of the inner surface in terms of area ratio, and the sulfide precipitated from the soft copper phase and the copper phase.
  • the sliding characteristics can be further improved by copper.
  • a flat copper powder having a particle size of about 20 to 150 ⁇ m can be preferably used.
  • the copper powder having a small particle size easily enters the gap between the iron particles, and the excessive copper powder is less likely to be ubiquitous around the core rod.
  • the ratio of the particle diameter to the thickness is preferably about 2.5 to 20.
  • S sulfur
  • Fe combines with Fe forming the base to form iron sulfide, and combines with Cu forming the copper phase to form copper sulfide.
  • the iron powder as the main raw material contains a very small amount (1% by mass or less) of Mn as an inevitable impurity resulting from the production method. For this reason, manganese sulfide can be dispersed in a very small part.
  • Mn manganese sulfide
  • These sulfides are rich in lubricity, and by depositing and dispersing such sulfides in the matrix, it is possible to form a matrix that exhibits excellent lubricating properties even under sliding conditions where metal contact is likely to occur. .
  • S is added to the raw material powder by adding it in the form of iron sulfide powder.
  • S added in the form of iron sulfide generates an eutectic liquid phase of Fe—S when the temperature rises in the sintering process at a temperature higher than 988 ° C., and liquid phase sintering proceeds to cause necking between powder particles. Promote growth. Further, after S is uniformly diffused from the eutectic liquid phase into the iron matrix, it again precipitates as iron sulfide particles from the crystal grain boundaries and crystal grains of the matrix. For this reason, the iron sulfide particles are uniformly dispersed in the crystal grain boundaries and crystal grains of the base, thereby improving the adhesion of the iron sulfide particles.
  • a part of S can diffuse into the copper phase, bond with Cu in the copper phase, and precipitate as copper sulfide particles within the crystal grain boundaries and crystal grains of the copper phase. Since the copper sulfide particles are thus precipitated and dispersed in the crystal grain boundaries and crystal grains of the copper phase, the adhesiveness is high.
  • the amount of S is insufficient, the amount of sulfide dispersed in the base becomes insufficient, and the lubrication characteristics become poor. If the amount of S is excessive, the amount of sulfide to be precipitated becomes excessive and the strength of the base decreases, and as a result, the mechanical strength of the iron-based sintered alloy constituting the iron-based sintered bearing decreases. . For this reason, the amount of S is preferably 0.3-2% by mass. At this time, the sulfide phase in the metal structure of the cross section of the iron-based sintered alloy is 0.9 to 6% in terms of the area ratio with respect to the area of the cross section including the pores when the cross section of the metal structure is observed.
  • the sulfide is preferably dispersed in a granular form in the metal structure. Also, if the size of the precipitated sulfide particles is coarse, the presence of sulfide particles is unevenly distributed, and in places where the presence of sulfide particles is poor, wear, adhesion, etc. are likely to occur during metal contact. A state where the particles are dispersed as particles having a maximum particle diameter of 50 ⁇ m or less is preferable.
  • C carbon
  • the matrix is composed of a pearlite single phase structure or a mixed structure of ferrite and pearlite
  • a part of C diffuses into the Fe powder particles constituting the matrix and forms a pearlite. This contributes to improving the mechanical strength of the base.
  • the graphite phase is formed by the graphite powder particles remaining in the iron-based sintered alloy in an undiffused state. For this reason, the graphite phase is dispersed in the pores.
  • the amount of C is set to 1 to 5% by mass.
  • Use of graphite powder having an average particle size of about 40 to 80 ⁇ m is preferable in terms of diffusion to the base and sliding properties.
  • the iron-based sintered alloy constituting the iron-based sintered bearing has a total composition of Cu: 0.5 to 3% and C: 1 to 5% in mass ratio. S: 0.3-2%, balance: Fe and inevitable impurities, the porosity of the iron-based sintered alloy is 10-25%, and the metal structure of the iron-based sintered alloy is a ferrite structure, It is one of a pearlite structure and a mixed structure of ferrite and pearlite, and a copper phase and a graphite phase are dispersed in the matrix, and a sulfide phase is precipitated and dispersed from the matrix and / or the copper phase. Presents a metal structure.
  • the area ratio of the sulfide phase is based on an image obtained by observing the cross section or surface of an iron-based sintered bearing (iron-based sintered alloy) with a metal microscope, an electron beam microanalyzer (EPMA), or the like. It can be measured using image analysis software such as WinROOF manufactured by Mitani Corporation.
  • an iron-based sintered bearing in the present invention as a raw material powder of the iron-based sintered alloy constituting the iron-based sintered bearing, copper powder, graphite powder, and iron sulfide powder are added to the iron powder.
  • the manufacturing method of the iron-based sintered bearing includes a step of forming the raw material powder into a bearing shape, that is, a substantially circular tube or a substantially annular shape having an inner diameter surface that slides with the shaft, and the obtained molding A step of sintering the body.
  • the iron-based sintered bearing is formed so that the density of the sintered iron-based sintered alloy is 5.2 to 7.2 g / cm 3 by setting the molding pressure of the raw material powder to 250 to 650 MPa. Can be manufactured.
  • the sintering temperature is preferably 990 ° C. or higher.
  • the sintering temperature is too high, the graphite phase diffuses to the base and the remaining graphite phase becomes poor, and the copper powder melts and the copper phase becomes poor.
  • S easily reacts with hydrogen and oxygen, if the sintering atmosphere is an oxidizing gas, the S component introduced into the raw material powder is released and the amount of S in the iron-based sintered alloy decreases.
  • a method for producing an iron-based sintered oil-impregnated bearing includes a step of preparing an iron-based sintered bearing according to the method for producing an iron-based sintered bearing as described above, and impregnating the iron-based sintered bearing with a lubricating oil.
  • An impregnation step, and if necessary, the iron-based sintered bearing before impregnation may be subjected to final compression processing such as sizing and coining.
  • Lubricating oils can be used by appropriately selecting from various lubricating oils in consideration of the application and operating environment. For example, one or a combination of two or more of mineral oils, synthetic hydrocarbon oils, ester oils, etc. are used. You can do it.
  • the density of the iron-based sintered alloy measured by the sintered density test method of the sintered metal material specified in Japanese Industrial Standard (JIS) Z2505 is in the range of 5.6 to 6.0 Mg / m 3 . Met.
  • the bearing samples of each sample number were impregnated with lubricating oil (mineral oil viscosity viscosity ISO ISO VG56), and the friction coefficient on the inner diameter surface of the sintered bearing was measured.
  • lubricating oil mineral oil viscosity viscosity ISO ISO VG56
  • a shaft made of carbon steel S45C was attached to the rotating shaft of a horizontal motor. The shaft was inserted into a bearing attached to the housing with a gap, and the shaft was rotated while a vertical load was applied to the housing.
  • the ambient temperature was maintained at 25 ° C.
  • the rotation speed of the shaft was set to 500 rpm
  • the load surface pressure was set to 0.3 MPa.
  • the effect of the C amount can be investigated by comparing the bearing samples with sample numbers 03 and 16 to 21 in Table 1. From Table 1, the bearing sample No. 16 having a C amount of 0.5% by mass has a large coefficient of friction because the graphite phase is poor. On the other hand, in the bearing sample of Sample No. 17 in which the addition amount of C is 1% by mass, a sufficient amount of graphite phase is formed and the friction coefficient can be reduced to 0.24. It can also be seen that the friction coefficient is reduced as the amount of C increases. On the other hand, the crushing strength decreases as the C content increases, and the crushing strength decreases to 140 MPa in the bearing sample of Sample No. 21 in which the C content exceeds 5 mass%.
  • the iron-based sintered oil-impregnated bearing according to the present invention is less likely to form a good lubricating oil film, and can exhibit good lubricating properties even under sliding conditions where metal contact is likely to occur. It supports shafts that rotate in the forward and reverse directions, such as paper feed rollers for copiers, head drive motors, etc., and is suitable as a bearing for applications where the forward and reverse drive times are short. It is suitable for a bearing that supports the shaft of a rotor that rotates eccentrically with respect to the stator, such as a compressor.

Abstract

Provided is a ferrous sinter oil-containing bearing that has a bearing surface for supporting the outer circumferential surface of a shaft, and has a ferrous sinter bearing, which is made of a ferrous sinter alloy in which pores are dispersed, and a lubricating oil impregnated in the pores. As mass ratios, the overall composition of the ferrous sinter alloy that makes up the ferrous sinter bearing is made of Cu: 0.5-3%, C: 1-5%, S: 0.3-2%, the balance being made of Fe and unavoidable impurities. The density of the ferrous sinter alloy is 5.2-7.2 g/cm3. The ferrous sinter alloy exhibits a metallographic structure wherein copper phases and graphite phases are dispersed in a base, which is one metal structure from among ferrite structures, pearlite structures and mixed ferrite and pearlite structures, and sulfide phases are precipitated from the base and/or copper phases and are dispersed.

Description

鉄系焼結含油軸受Iron-based sintered oil-impregnated bearing
　本発明は、軸の外周面を支持する軸受面を有する鉄系焼結含油軸受に関する。 The present invention relates to an iron-based sintered oil-impregnated bearing having a bearing surface that supports the outer peripheral surface of a shaft.
　軸の外周面を支持する軸受面を有するすべり軸受には、従来、焼結合金製の焼結軸受が多用されている。焼結含油軸受は、気孔を有する焼結合金製の焼結軸受の気孔中に潤滑油を含浸したものであり、含浸した潤滑油による自己潤滑性を付与できるため、耐焼付き性と耐摩耗性が良好で広く用いられている。 Conventionally, a sintered bearing made of a sintered alloy has been widely used as a slide bearing having a bearing surface that supports the outer peripheral surface of the shaft. Sintered oil-impregnated bearings are a sintered bearing made of a sintered alloy having pores, the pores of which are impregnated with lubricating oil, and can provide self-lubricating properties due to the impregnated lubricating oil. Is good and widely used.
　焼結含油軸受の潤滑理論を、図１を参照して説明する。焼結含油軸受の本体である焼結軸受１を構成する焼結体は、金属基地中に気孔が分散する多孔質体であり、気孔中に潤滑油２が含浸されている。焼結軸受は略円管又は略円環に形成され、その内周面で軸３を支承する。ここで、軸が回転すると、軸との摩擦熱により気孔に含浸された潤滑油が熱膨張するとともに、軸の回転により気孔中に含浸された潤滑油が吸い出され、図１に矢印４で示すように、油圧の低い上の部分から高い油圧を受ける摺動部に向かって潤滑油が流れる。この潤滑油の流れによって軸受の内周面から軸を持ち上げて、軸受内周面と軸との金属接触を防止する。また、軸と軸受内周面の間に入り込む潤滑油の流れによって、軸は回転方向に片寄せられ、軸受内周面での油圧分布５は図１のようになる。一方、油圧が生じても気孔を通じて潤滑油が逃げるため、気孔を通じて潤滑油が焼結軸受内を循環して、再び内周面で効果的な潤滑作用を発揮する。軸の回転が停止すると、熱膨張していた潤滑油は収縮するとともに、潤滑油が気孔中に毛細管力により吸収されて初期状態に戻る。これを繰り返すことで、長期にわたり、無給油で良好な潤滑特性を発揮する。 The lubrication theory of sintered oil-impregnated bearings will be described with reference to FIG. A sintered body constituting the sintered bearing 1 which is a main body of the sintered oil-impregnated bearing is a porous body in which pores are dispersed in a metal matrix, and the lubricant 2 is impregnated in the pores. The sintered bearing is formed in a substantially circular tube or a substantially annular ring, and supports the shaft 3 on its inner peripheral surface. Here, when the shaft rotates, the lubricating oil impregnated in the pores is thermally expanded due to frictional heat with the shaft, and the lubricating oil impregnated in the pores is sucked out by the rotation of the shaft. As shown, the lubricating oil flows from the upper part of the low oil pressure toward the sliding part that receives the high oil pressure. The shaft is lifted from the inner peripheral surface of the bearing by the flow of the lubricating oil to prevent metal contact between the inner peripheral surface of the bearing and the shaft. Further, the flow of lubricating oil entering between the shaft and the inner peripheral surface of the bearing causes the shaft to be shifted in the rotational direction, and the hydraulic pressure distribution 5 on the inner peripheral surface of the bearing is as shown in FIG. On the other hand, since the lubricating oil escapes through the pores even when hydraulic pressure is generated, the lubricating oil circulates through the pores in the sintered bearing and exhibits an effective lubricating action on the inner peripheral surface again. When the rotation of the shaft stops, the thermally expanded lubricating oil contracts, and the lubricating oil is absorbed into the pores by the capillary force and returns to the initial state. By repeating this, good lubrication characteristics are exhibited without lubrication over a long period of time.
　軸受が支持する軸は、一般に安価な鉄合金からなり、焼結軸受には、銅系の焼結合金が適用された銅系焼結軸受が多用されてきた。近年、銅の価格が高騰しているため、安価な鉄を主成分とする鉄系焼結合金を用いた鉄系焼結軸受に対するニーズが高まってきている。しかし、このような鉄を主成分とする軸受の場合には、焼付き易く、また、相手部品であるシャフトを傷付け易いという欠点がある。特に、熱処理を施していない硬さが低いシャフトと鉄を主成分とする軸受とを組み合わせて用いると、上記の現象は顕著となる。 The shaft supported by the bearing is generally made of an inexpensive iron alloy, and a copper-based sintered bearing to which a copper-based sintered alloy is applied has been frequently used as the sintered bearing. In recent years, since the price of copper has soared, the need for an iron-based sintered bearing using an iron-based sintered alloy whose main component is inexpensive iron is increasing. However, in the case of such a bearing containing iron as a main component, there are disadvantages that it is easy to seize and the shaft which is a counterpart part is easily damaged. In particular, the above phenomenon becomes prominent when a low-hardness shaft that has not been heat-treated and a bearing mainly composed of iron are used in combination.
　このような状況の下、特許文献１では、優れた耐摩耗性を有するとともに、鉄銅系焼結合金を用いた鉄銅系焼結軸受に匹敵する耐焼付き性および相手部品への攻撃緩和性を有するものとして、鉄系焼結軸受が提案されている。この軸受は、焼結合金の全体組成が、質量比で、Ｃｕ：２．０～９．０％、Ｃ：１．５～３．７％、残部：Ｆｅおよび不可避不純物からなり、軸受の内部は、面積率でフェライトが２０～８５％および残部がパーライトからなる鉄合金相中に、軸受の軸方向に対して交差する方向に延在する銅相と、黒鉛相および気孔が分散する金属組織を示し、軸受面に、銅相が８～４０％の面積率で露出する。 Under such circumstances, Patent Document 1 has excellent wear resistance, seizure resistance comparable to iron-copper sintered bearings using iron-copper-based sintered alloys, and attack mitigation to counterpart parts. Iron-based sintered bearings have been proposed as having the above. In this bearing, the total composition of the sintered alloy is, by mass ratio, Cu: 2.0 to 9.0%, C: 1.5 to 3.7%, the balance: Fe and inevitable impurities. Is a metal structure in which a copper phase extending in a direction crossing the axial direction of the bearing, a graphite phase, and pores are dispersed in an iron alloy phase composed of 20 to 85% ferrite by area and the balance of pearlite. The copper phase is exposed on the bearing surface at an area ratio of 8 to 40%.
　また、内周面に高い面圧が作用するような軸受に用いて好適な摺動部材用鉄基焼結合金として、全体組成が、質量比で、Ｃ：０．６～１．２％、Ｃｕ：３．５～９．０％、Ｍｎ：０．６～２．２％、Ｓ：０．４～１．３％、残部：Ｆｅおよび不可避不純物からなる摺動部材用鉄基焼結合金が提案（特許文献２）されており、その合金組織は、マルテンサイト基地中に、遊離したＣｕ相及び遊離したＣｕ－Ｆｅ合金相の少なくとも一方が分散しているとともに、ＭｎＳ相が１．０～３．５質量％分散していることを特徴とする。 Further, as an iron-based sintered alloy for a sliding member suitable for use in a bearing in which a high surface pressure acts on the inner peripheral surface, the overall composition has a mass ratio of C: 0.6 to 1.2%, Cu: 3.5 to 9.0%, Mn: 0.6 to 2.2%, S: 0.4 to 1.3%, balance: Fe-based sintered alloy for sliding members comprising Fe and inevitable impurities Has been proposed (Patent Document 2), and the alloy structure is such that at least one of the free Cu phase and the free Cu—Fe alloy phase is dispersed in the martensite matrix, and the MnS phase is 1.0. It is characterized by being dispersed by 3.5% by mass.
特開２０１０－０７７４７４号公報JP 2010-077744 特開２００９－１５５６９６号公報JP 2009-155696 A
　上記のように、焼結含油軸受は、軸の回転により気孔中から引き出された潤滑油が、軸の回転につれて軸と軸受内周面と間に引き込まれ、軸と軸受の内周面の間に油膜を形成することで軸と軸受の内周面の金属接触を防止して良好な潤滑特性を示す。このため、各種用途への適用が進んでいるが、良好な油膜を形成しにくい用途に対しては、その適用が進んでいない。更なる用途拡大のためには、焼結軸受のさらなる改良が必要である。 As described above, in the sintered oil-impregnated bearing, the lubricating oil drawn from the pores by the rotation of the shaft is drawn between the shaft and the inner peripheral surface of the bearing as the shaft rotates, and between the shaft and the inner peripheral surface of the bearing. By forming an oil film on the shaft, metal contact between the shaft and the inner peripheral surface of the bearing is prevented, and good lubrication characteristics are exhibited. For this reason, the application to various uses is progressing, but the application is not progressing for uses that are difficult to form a good oil film. For further application expansion, further improvement of the sintered bearing is necessary.
　このような焼結含油軸受の適用が難しいと考えられてきた分野として、例えば、複写機等の紙送りローラや、ヘッド駆動モータ等のような、正逆に回転する軸を支承するとともに、正転、逆転それぞれの駆動時間が短い用途のための軸受がある。このような用途の場合、図２（ａ）に示すように、良好な潤滑油膜が形成される前に回転が停止することから、軸と軸受の内周面との金属接触が発生しやすい。 Fields in which such sintered oil-impregnated bearings have been considered difficult to apply include, for example, supporting forward and reverse rotating shafts such as paper feed rollers for copiers, head drive motors, etc. There are bearings for applications where the driving time for each rotation and reverse rotation is short. In such an application, as shown in FIG. 2A, the rotation stops before a good lubricating oil film is formed, and therefore metal contact between the shaft and the inner peripheral surface of the bearing is likely to occur.
　また、スクロール式圧縮機等のような、固定子に対して偏心して回転する回転子の軸を支承する軸受としての用途においては、図２（ｂ）に示すように、軸受内周面に対して軸の位置が偏心して移動することとなる。このような用途においても、良好な潤滑油膜を形成することが難しく、軸と軸受の内周面との金属接触が発生しやすい。 In applications such as a scroll compressor that supports a shaft of a rotor that rotates eccentrically with respect to a stator, as shown in FIG. As a result, the position of the shaft moves eccentrically. Even in such applications, it is difficult to form a good lubricating oil film, and metal contact between the shaft and the inner peripheral surface of the bearing tends to occur.
　これらの用途においては、ポリテトラフルオロエチレン（ＰＴＦＥ）等のフッ素系樹脂で内周面を構成したすべり軸受が適用されているが、軟質なフッ素系樹脂は、摩耗が生じ易く、耐久性に問題がある。したがって、このような金属接触が発生しやすい用途であっても、良好な摺動特性を示す焼結軸受が提供できれば、焼結軸受の適用が拡大できることとなる。 In these applications, slide bearings whose inner peripheral surface is made of a fluororesin such as polytetrafluoroethylene (PTFE) are applied. However, soft fluororesins tend to wear out and have a problem with durability. There is. Therefore, even if it is an application in which such metal contact is likely to occur, the application of the sintered bearing can be expanded if a sintered bearing showing good sliding characteristics can be provided.
　この点について、特許文献１の鉄系焼結軸受は、良好な潤滑油膜が形成できる用途に対しては優れた耐摩耗性を有し、鉄銅系焼結含油軸受に匹敵する耐焼付き性および相手部品への攻撃緩和性を有する。しかし、金属接触が発生しやすい用途に対しては、さらなる改良が必要である。 In this regard, the iron-based sintered bearing of Patent Document 1 has excellent wear resistance for applications in which a good lubricating oil film can be formed, and has seizure resistance comparable to that of an iron-copper-based sintered oil-impregnated bearing. Has mitigation against attacks on opponent parts. However, further improvements are needed for applications where metal contact is likely to occur.
　一方、特許文献２の鉄基焼結摺動部材は、遊離したＣｕ相またはＣｕ－Ｆｅ合金相とＭｎＳ相によって潤滑を行い、摺動特性を発揮する。この点に関して、ＭｎＳ相は、原料粉末に添加したＭｎＳ粉末がそのまま残留して形成されるので、ＭｎＳ相は鉄粉末どうしの粒界（粉末粒界）のみに分散する。しかし、ＭｎＳ粉末は、安定で、他の粉末と反応しないので、基地を形成する鉄粉末と反応せず、従って、基地への固着性が悪い。また、鉄粉末の粒界に存在して鉄粉末粒子どうしの結合を阻害するので、基地の強度が低下する虞がある。 On the other hand, the iron-based sintered sliding member of Patent Document 2 is lubricated by the released Cu phase or Cu—Fe alloy phase and MnS phase, and exhibits sliding characteristics. In this regard, since the MnS phase is formed by leaving the MnS powder added to the raw material powder as it is, the MnS phase is dispersed only at the grain boundaries (powder grain boundaries) between the iron powders. However, since the MnS powder is stable and does not react with other powders, it does not react with the iron powder forming the matrix, and therefore the adhesion to the matrix is poor. Moreover, since it exists in the grain boundary of iron powder and the coupling | bonding of iron powder particles is inhibited, there exists a possibility that the intensity | strength of a base may fall.
　本発明は、固着性の乏しい特許文献２の手法によらず、鉄系焼結含油軸受に対して、よりいっそうの潤滑特性の向上を果たし、金属接触が発生しやすい用途においても良好な潤滑特性を示す鉄系焼結軸受およびその製造方法を提供することを目的とする。 The present invention does not depend on the technique of Patent Document 2 with poor adhesion, and further improves the lubrication characteristics for iron-based sintered oil-impregnated bearings, and also has excellent lubrication characteristics even in applications where metal contact is likely to occur. It aims at providing the iron system sintered bearing which shows this, and its manufacturing method.
　本発明者らは、上記目的を達成する鉄系焼結軸受につき検討し、鉄系焼結軸受の本体を構成する鉄系焼結合金の基地中に硫化物を析出分散させることで、金属接触が発生しやすい用途においても良好な潤滑特性を示すことができることを見出した。
　本発明の一態様によれば、鉄系焼結含油軸受は、軸の外周面を支持する軸受面を有し、気孔が分散する鉄系焼結合金で構成される鉄系焼結軸受と、前記気孔に含浸された潤滑油とを有する鉄系焼結含油軸受であって、前記鉄系焼結合金の全体組成が、質量比で、Ｃｕ：０．５～３％、Ｃ：１～５％、Ｓ：０．３～２％、残部：Ｆｅおよび不可避不純物からなり、前記鉄系焼結合金の密度が５．２～７．２ｇ／ｃｍ３であり、前記鉄系焼結合金は、フェライト組織、パーライト組織、及び、フェライトとパーライトとの混合組織のうちの１つの金属組織を有する基地と、前記基地中に分散する銅相及び黒鉛相と、前記基地および前記銅相の少なくとも一方から析出して分散する硫化物相とを有することを要旨とする。 The inventors of the present invention have studied an iron-based sintered bearing that achieves the above object, and depositing and dispersing sulfides in the base of the iron-based sintered alloy constituting the main body of the iron-based sintered bearing, thereby providing a metal contact It has been found that good lubrication characteristics can be exhibited even in applications where the occurrence of such a tendency to occur.
According to one aspect of the present invention, an iron-based sintered oil-impregnated bearing has a bearing surface that supports the outer peripheral surface of the shaft, and an iron-based sintered bearing configured of an iron-based sintered alloy in which pores are dispersed; An iron-based sintered oil-impregnated bearing having lubricating oil impregnated in the pores, wherein the total composition of the iron-based sintered alloy is Cu: 0.5 to 3%, C: 1 to 5 %, S: 0.3-2%, balance: Fe and inevitable impurities, the density of the iron-based sintered alloy is 5.2-7.2 g / cm 3 , From a base having one metal structure of a ferrite structure, a pearlite structure, and a mixed structure of ferrite and pearlite, a copper phase and a graphite phase dispersed in the base, and at least one of the base and the copper phase The gist is to have a sulfide phase that precipitates and disperses.
　上記鉄系焼結軸受において、前記硫化物相は、前記基地および前記銅相の結晶粒界および結晶粒内に析出して分散すると良く、前記硫化物は、硫化鉄および硫化銅が主体であってよい。また、鉄系焼結軸受は、前記金属組織に分散する硫化物相が、金属組織の断面を観察した時に気孔を含む断面の面積に対して０．９～６％の面積率で分散していると良好であり、前記硫化物相が粒状であり、最大粒径が５０μｍ以下であると良い。さらに、前記軸受面に分散する銅相および硫化銅相が軸受面全体に対して５～２０％の面積率で分散していると好適である。 In the iron-based sintered bearing, the sulfide phase may be precipitated and dispersed within crystal boundaries and crystal grains of the matrix and the copper phase, and the sulfide is mainly composed of iron sulfide and copper sulfide. It's okay. In the iron-based sintered bearing, the sulfide phase dispersed in the metal structure is dispersed at an area ratio of 0.9 to 6% with respect to the area of the cross section including pores when the cross section of the metal structure is observed. The sulfide phase is granular and the maximum particle size is preferably 50 μm or less. Further, it is preferable that the copper phase and the copper sulfide phase dispersed on the bearing surface are dispersed at an area ratio of 5 to 20% with respect to the entire bearing surface.
　本発明の実施形態によれば、鉄系焼結軸受は、潤滑特性について優れた改善が施され、金属接触が発生しやすい用途においても良好な潤滑特性を示すものである。 According to the embodiment of the present invention, the iron-based sintered bearing is excellently improved in lubrication characteristics and exhibits good lubrication characteristics even in applications where metal contact is likely to occur.
焼結軸受の潤滑作用を説明する模式図である。It is a schematic diagram explaining the lubrication effect | action of a sintered bearing. 良好な潤滑油膜が形成されない場合を説明する模式図である。It is a schematic diagram explaining the case where a favorable lubricating oil film is not formed. 本発明における鉄系焼結軸受を構成する鉄系焼結合金の金属組織の一例を示す図面代用写真である。It is a drawing substitute photograph which shows an example of the metal structure of the iron-type sintered alloy which comprises the iron-type sintered bearing in this invention.
　以下、本発明における鉄系焼結含油軸受の本体である鉄系焼結軸受を構成する鉄系焼結合金の金属組織および数値特定の根拠を、本発明の作用とともに説明する。 Hereinafter, the metal structure of the iron-based sintered alloy constituting the iron-based sintered bearing that is the main body of the iron-based sintered oil-impregnated bearing in the present invention and the basis for specifying the numerical values will be described together with the operation of the present invention.
　本発明において、鉄系焼結含油軸受の本体である鉄系焼結軸受は、Ｆｅ（鉄）を主成分とする鉄系焼結合金によって構成される。鉄系焼結合金は、例えば、図３に示すように、鉄系の基地（図３においてはフェライト相Ｐ１）と、銅相Ｐ２と、黒鉛相Ｐ３と、硫化物相Ｐ４とを含んでいる。Ｆｅは、Ｃｕ（銅）に比して安価であり、機械的強さに優れることから、鉄系焼結合金の主成分として好適な成分である。Ｆｅは、鉄粉末の形態で導入され、鉄粉末を主成分とする原料粉末を用いることによって、鉄系焼結合金の基地が形成される。鉄系焼結合金の基地には、気孔が分散する。気孔は、粉末冶金法に起因して生じるものであり、原料粉末を圧粉成形した際の粉末粒子間の空隙が、原料粉末の結合によって形成された基地中に残留したものである。 In the present invention, the iron-based sintered bearing which is the main body of the iron-based sintered oil-impregnated bearing is composed of an iron-based sintered alloy containing Fe (iron) as a main component. For example, as shown in FIG. 3, the iron-based sintered alloy includes an iron-based matrix (ferrite phase P1 in FIG. 3), a copper phase P2, a graphite phase P3, and a sulfide phase P4. . Fe is a component suitable as a main component of an iron-based sintered alloy because it is cheaper than Cu (copper) and has excellent mechanical strength. Fe is introduced in the form of iron powder, and the base of the iron-based sintered alloy is formed by using the raw material powder mainly composed of iron powder. The pores are dispersed in the base of the iron-based sintered alloy. The pores are caused by the powder metallurgy method, and voids between the powder particles when the raw material powder is compacted are left in the base formed by the bonding of the raw material powders.
　鉄系焼結合金の基地の金属組織は、フェライト組織、パーライト組織、及び、フェライトとパーライトとの混合組織のうちの１つである。フェライトは、軟質であり、相手材となる軸とのなじみ性が良好であるが、機械的強さが低い。一方、パーライトは、基地硬さが高く、機械的強さが高いが、相手材となる軸を摩耗させる虞がある。このため、鉄系焼結合金の基地の金属組織は、鉄系焼結軸受の要求特性に応じて、フェライト単相の金属組織、フェライトとパーライトが混合した金属組織、パーライト単相の金属組織のいずれかである。 The base metal structure of the iron-based sintered alloy is one of a ferrite structure, a pearlite structure, and a mixed structure of ferrite and pearlite. Ferrite is soft and has good compatibility with the shaft that is the counterpart material, but has low mechanical strength. On the other hand, pearlite has a high base hardness and a high mechanical strength, but there is a possibility that the shaft that is the counterpart material is worn. For this reason, the base metal structure of the iron-based sintered alloy depends on the required characteristics of the iron-based sintered bearing, including a ferrite single-phase metal structure, a mixed metal structure of ferrite and pearlite, and a pearlite single-phase metal structure. Either.
　上述したように、焼結合金には製法に起因する気孔が形成されるため、焼結合金の密度（焼結体密度）は、理論密度よりも低くなる。焼結合金の密度が高いと、気孔量が少なくなり、焼結合金の密度が低いと気孔量が多くなる。焼結軸受においては、このような気孔を利用して、鉄系焼結合金に形成される気孔に潤滑油を含浸することで、無給油で長期にわたる潤滑特性を発揮する。本発明において、鉄系焼結軸受を構成する鉄系焼結合金に形成される気孔量が乏しい、すなわち鉄系焼結合金の密度が高いと、含浸される潤滑油の量が乏しくなり、良好な潤滑特性が発揮できなくなる。一方、鉄系焼結合金に形成される気孔量が過多、すなわち鉄系焼結合金の密度が低いと、鉄系焼結合金の基地の量が少なくなる結果、鉄系焼結合金の機械的強さが低下することとなる。この観点より、鉄系焼結合金の密度は５．２～７．２ｇ／ｃｍ３とするとよい。この鉄系焼結合金の密度は、鉄系焼結合金の気孔率でおよそ１０～２５％に相当する。なお、焼結体の密度比は、日本工業規格（ＪＩＳ）Ｚ２５０５に規定の金属焼結材料の焼結密度試験方法により測定される。 As described above, since pores resulting from the production method are formed in the sintered alloy, the density of the sintered alloy (sintered body density) is lower than the theoretical density. When the density of the sintered alloy is high, the amount of pores decreases, and when the density of the sintered alloy is low, the amount of pores increases. In the sintered bearing, by using such pores, the pores formed in the iron-based sintered alloy are impregnated with a lubricating oil, thereby exhibiting lubrication characteristics for a long time without lubrication. In the present invention, the amount of pores formed in the iron-based sintered alloy constituting the iron-based sintered bearing is poor, that is, if the density of the iron-based sintered alloy is high, the amount of lubricating oil impregnated becomes small and good. The proper lubrication properties cannot be achieved. On the other hand, if the amount of pores formed in the iron-based sintered alloy is excessive, that is, if the density of the iron-based sintered alloy is low, the amount of iron-based sintered alloy base decreases, resulting in the mechanical properties of the iron-based sintered alloy. Strength will decrease. From this viewpoint, the density of the iron-based sintered alloy or equal to 5.2 ~ 7.2g / cm 3. The density of the iron-based sintered alloy corresponds to approximately 10 to 25% in terms of the porosity of the iron-based sintered alloy. In addition, the density ratio of a sintered compact is measured by the sintering density test method of a metal sintered material prescribed | regulated to Japanese Industrial Standard (JIS) Z2505.
　Ｃｕは、軟質な銅相を形成して、相手材となる軸とのなじみ性を良好なものとするとともに、潤滑性に優れる硫化銅を形成して潤滑性を向上させることが可能な成分である。Ｃｕ量が乏しいと、基地中に分散する銅相が乏しくなり、上記効果が乏しくなる。一方、高価なＣｕが過大であると、その分、コストが増加することとなる。このため、Ｃｕ量は０．５～３質量％とする。 Cu is a component that can form a soft copper phase to improve the compatibility with the mating shaft and improve the lubricity by forming copper sulfide with excellent lubricity. is there. When the amount of Cu is poor, the copper phase dispersed in the base becomes poor and the above effect becomes poor. On the other hand, if the expensive Cu is excessive, the cost increases accordingly. For this reason, the amount of Cu is 0.5-3 mass%.
　Ｃｕは、原料粉末中に銅粉末の形態で付与される。なお、銅粉末は、扁平状あるいは箔状の銅粉末を用いることが好ましい。Ｃｕ原料として扁平状の銅粉を用いると、ダイキャビティ内を原料粉末が落下する際に、コアロッドに扁平状の銅粉がまとわり付き、コアロッドに銅粉が張り付いた状態となるため、軸受内部と比較して摺動特性が求められる軸受内径面に露出する銅相の量が多くなる。従って、軸受内部のＣｕ量を低減して全体組成中のＣｕ量を削減しても、軸受内径面に露出する銅相の量を必要量に維持することができる。この点に関し、軸受内径面に分散する銅相および後述する硫化銅相の合計の適量を面積率で内径面の５～２０％とすることができ、軟質な銅相および銅相から析出する硫化銅によって、摺動特性をより向上させることができる。扁平状の銅粉は、粒径が２０～１５０μｍ程度のものを好適に用いることができる。粒径が小さい銅粉は、鉄粒子間の間隙に入り易く、過大な銅粉は、コアロッド周囲に遍在し難くなる。粒子径と厚さとの比は、２．５～２０程度であると好適である。 Cu is applied to the raw material powder in the form of copper powder. The copper powder is preferably a flat or foil copper powder. When flat copper powder is used as the Cu raw material, when the raw powder falls in the die cavity, the flat copper powder clings to the core rod, and the copper powder sticks to the core rod. The amount of copper phase exposed on the inner diameter surface of the bearing, which requires sliding characteristics, is larger than that in the bearing. Therefore, even if the amount of Cu in the bearing is reduced to reduce the amount of Cu in the entire composition, the amount of the copper phase exposed on the inner diameter surface of the bearing can be maintained at a required amount. In this regard, the appropriate amount of the total of the copper phase dispersed on the bearing inner surface and the copper sulfide phase described later can be 5 to 20% of the inner surface in terms of area ratio, and the sulfide precipitated from the soft copper phase and the copper phase. The sliding characteristics can be further improved by copper. A flat copper powder having a particle size of about 20 to 150 μm can be preferably used. The copper powder having a small particle size easily enters the gap between the iron particles, and the excessive copper powder is less likely to be ubiquitous around the core rod. The ratio of the particle diameter to the thickness is preferably about 2.5 to 20.
　Ｓ（硫黄）は、基地を形成するＦｅと結合して硫化鉄を形成するとともに、銅相を形成するＣｕと結合して硫化銅を形成する。なお、主原料である鉄粉末は、製法に起因する不可避不純物として極微量（１質量％以下）のＭｎを含有する。このため、ごく一部に硫化マンガンも分散し得る。これらの硫化物は、潤滑性に富み、このような硫化物を基地中に析出分散させることで、金属接触が発生しやすい摺動条件の下でも、優れた潤滑特性を発揮する基地を形成できる。 S (sulfur) combines with Fe forming the base to form iron sulfide, and combines with Cu forming the copper phase to form copper sulfide. The iron powder as the main raw material contains a very small amount (1% by mass or less) of Mn as an inevitable impurity resulting from the production method. For this reason, manganese sulfide can be dispersed in a very small part. These sulfides are rich in lubricity, and by depositing and dispersing such sulfides in the matrix, it is possible to form a matrix that exhibits excellent lubricating properties even under sliding conditions where metal contact is likely to occur. .
　Ｓは、硫化鉄粉末の形態で添加することで原料粉末に付与される。硫化鉄の形態で付与されたＳは、焼結工程の昇温過程において９８８℃を超えるとＦｅ－Ｓの共晶液相を発生し、液相焼結が進行して粉末粒子間のネックの成長を促進する。また、この共晶液相からＳが鉄基地中に均一に拡散した後、基地の結晶粒界および結晶粒内から再度硫化鉄粒子として析出する。このため、基地の結晶粒界および結晶粒内に硫化鉄粒子が均一に分散し、これにより、硫化鉄粒子の固着性を高めることができる。また、Ｓの一部は、銅相に拡散して、銅相中のＣｕと結合して銅相の結晶粒界および結晶粒内に硫化銅粒子として析出し得る。硫化銅粒子も、このように銅相の結晶粒界および結晶粒内に析出して分散するので、固着性が高い。 S is added to the raw material powder by adding it in the form of iron sulfide powder. S added in the form of iron sulfide generates an eutectic liquid phase of Fe—S when the temperature rises in the sintering process at a temperature higher than 988 ° C., and liquid phase sintering proceeds to cause necking between powder particles. Promote growth. Further, after S is uniformly diffused from the eutectic liquid phase into the iron matrix, it again precipitates as iron sulfide particles from the crystal grain boundaries and crystal grains of the matrix. For this reason, the iron sulfide particles are uniformly dispersed in the crystal grain boundaries and crystal grains of the base, thereby improving the adhesion of the iron sulfide particles. Moreover, a part of S can diffuse into the copper phase, bond with Cu in the copper phase, and precipitate as copper sulfide particles within the crystal grain boundaries and crystal grains of the copper phase. Since the copper sulfide particles are thus precipitated and dispersed in the crystal grain boundaries and crystal grains of the copper phase, the adhesiveness is high.
　Ｓ量が乏しいと、基地中に分散する硫化物の量が乏しくなり、潤滑特性が乏しくなる。Ｓ量が過剰であると、析出する硫化物の量が過多となって基地の強度が低下し、その結果、鉄系焼結軸受を構成する鉄系焼結合金の機械的強さが低下する。このようなことから、Ｓ量は０．３～２質量％とするよい。このとき、鉄系焼結合金の断面の金属組織における硫化物相は、金属組織の断面を観察した時に気孔を含む断面の面積に対する面積率で、０．９～６％となる。 If the amount of S is insufficient, the amount of sulfide dispersed in the base becomes insufficient, and the lubrication characteristics become poor. If the amount of S is excessive, the amount of sulfide to be precipitated becomes excessive and the strength of the base decreases, and as a result, the mechanical strength of the iron-based sintered alloy constituting the iron-based sintered bearing decreases. . For this reason, the amount of S is preferably 0.3-2% by mass. At this time, the sulfide phase in the metal structure of the cross section of the iron-based sintered alloy is 0.9 to 6% in terms of the area ratio with respect to the area of the cross section including the pores when the cross section of the metal structure is observed.
　硫化物は、金属組織中に粒状で分散することが好ましい。また、析出する硫化物粒子の大きさが粗大であると、硫化物粒子の存在箇所が偏在し、硫化物粒子の存在が乏しい箇所において、金属接触時に摩耗、凝着等が生じ易くなるので、最大粒子径で５０μｍ以下の粒子として分散する状態が好ましい。 The sulfide is preferably dispersed in a granular form in the metal structure. Also, if the size of the precipitated sulfide particles is coarse, the presence of sulfide particles is unevenly distributed, and in places where the presence of sulfide particles is poor, wear, adhesion, etc. are likely to occur during metal contact. A state where the particles are dispersed as particles having a maximum particle diameter of 50 μm or less is preferable.
　Ｃ（炭素）は、黒鉛粉末の形態で付与され、黒鉛相を形成して鉄系焼結合金に潤滑性を付与する。また、基地をパーライトの単相組織、または、フェライトとパーライトとの混合組織で構成する場合に、Ｃの一部が、基地を構成するＦｅ粉末粒子に拡散して固溶し、パーライトを形成して基地の機械的強さの向上に寄与する。黒鉛相は、黒鉛粉末粒子が、未拡散の状態で鉄系焼結合金中に残留することで形成される。このため、黒鉛相は、気孔中に分散することになる。 C (carbon) is imparted in the form of graphite powder, and forms a graphite phase to impart lubricity to the iron-based sintered alloy. In addition, when the matrix is composed of a pearlite single phase structure or a mixed structure of ferrite and pearlite, a part of C diffuses into the Fe powder particles constituting the matrix and forms a pearlite. This contributes to improving the mechanical strength of the base. The graphite phase is formed by the graphite powder particles remaining in the iron-based sintered alloy in an undiffused state. For this reason, the graphite phase is dispersed in the pores.
　Ｃ量が乏しいと、鉄系焼結合金中に分散する黒鉛相の量が乏しくなり、潤滑特性が乏しくなる。一方で、Ｃ量が過多となると、分散する黒鉛相の量が過多となって、基地の強度が低下する結果、鉄系焼結軸受の本体を構成する鉄系焼結合金の機械的強さが低下することとなる。このためＣ量を１～５質量％とする。平均粒径が４０～８０μｍ程度の黒鉛粉末を使用すると、基地への拡散や摺動特性等の点において好適である。 If the amount of C is insufficient, the amount of the graphite phase dispersed in the iron-based sintered alloy will be insufficient, and the lubricating properties will be poor. On the other hand, if the amount of C is excessive, the amount of the graphite phase to be dispersed becomes excessive and the strength of the base is reduced. As a result, the mechanical strength of the iron-based sintered alloy constituting the main body of the iron-based sintered bearing Will be reduced. Therefore, the C amount is set to 1 to 5% by mass. Use of graphite powder having an average particle size of about 40 to 80 μm is preferable in terms of diffusion to the base and sliding properties.
　以上より、本発明の好適な実施形態において、鉄系焼結軸受を構成する鉄系焼結合金は、全体組成が、質量比で、Ｃｕ：０．５～３％、Ｃ：１～５％、Ｓ：０．３～２％、残部：Ｆｅおよび不可避不純物からなり、前記鉄系焼結合金の気孔率が１０～２５％であり、前記鉄系焼結合金の金属組織が、フェライト組織、パーライト組織、及び、フェライトとパーライトとの混合組織のうちの１つであり、基地中に銅相及び黒鉛相が分散するとともに、硫化物相が前記基地及び／又は銅相から析出して分散した金属組織を呈する。 As described above, in a preferred embodiment of the present invention, the iron-based sintered alloy constituting the iron-based sintered bearing has a total composition of Cu: 0.5 to 3% and C: 1 to 5% in mass ratio. S: 0.3-2%, balance: Fe and inevitable impurities, the porosity of the iron-based sintered alloy is 10-25%, and the metal structure of the iron-based sintered alloy is a ferrite structure, It is one of a pearlite structure and a mixed structure of ferrite and pearlite, and a copper phase and a graphite phase are dispersed in the matrix, and a sulfide phase is precipitated and dispersed from the matrix and / or the copper phase. Presents a metal structure.
　なお、硫化物相の面積率は、鉄系焼結軸受（鉄系焼結合金）の断面または表面を金属顕微鏡、電子線マイクロアナライザ（ＥＰＭＡ：Electron Probe Micro Analyzer）等によって観察した画像に基づいて、三谷商事株式会社製ＷｉｎＲＯＯＦ等の画像分析ソフトウエアを用いて測定することができる。 The area ratio of the sulfide phase is based on an image obtained by observing the cross section or surface of an iron-based sintered bearing (iron-based sintered alloy) with a metal microscope, an electron beam microanalyzer (EPMA), or the like. It can be measured using image analysis software such as WinROOF manufactured by Mitani Corporation.
　本発明における鉄系焼結軸受の製造方法において、鉄系焼結軸受を構成する鉄系焼結合金の原料粉末としては、鉄粉末に、銅粉末、黒鉛粉末、および、硫化鉄粉末を添加し混合して、質量比で、Ｃｕ：０．５～３％、Ｃ：１～５％、Ｓ：０．３～２％、残部：Ｆｅおよび不可避不純物からなる組成に調製された混合粉末を用いることができる。 In the method for producing an iron-based sintered bearing in the present invention, as a raw material powder of the iron-based sintered alloy constituting the iron-based sintered bearing, copper powder, graphite powder, and iron sulfide powder are added to the iron powder. Mix and use a mixed powder prepared in a composition consisting of Cu: 0.5 to 3%, C: 1 to 5%, S: 0.3 to 2%, balance: Fe and inevitable impurities by mass ratio be able to.
　鉄系焼結軸受の製造方法は、上記の原料粉末を、軸受形状、すなわち、軸と摺動する内径面を備えた略円管又は略円環の形状に成形する工程と、得られた成形体を焼結する工程を有する。成形工程において、原料粉末の成形圧力を２５０～６５０ＭＰａとすることで、焼結後の鉄系焼結合金の密度が５．２～７．２ｇ／ｃｍ３となるように鉄系焼結軸受を製造することができる。 The manufacturing method of the iron-based sintered bearing includes a step of forming the raw material powder into a bearing shape, that is, a substantially circular tube or a substantially annular shape having an inner diameter surface that slides with the shaft, and the obtained molding A step of sintering the body. In the molding step, the iron-based sintered bearing is formed so that the density of the sintered iron-based sintered alloy is 5.2 to 7.2 g / cm 3 by setting the molding pressure of the raw material powder to 250 to 650 MPa. Can be manufactured.
　焼結工程において、焼結温度が低すぎると、硫化鉄が溶融せず、鉄系焼結合金の基地中に硫化物を析出分散させることができなくなるので、焼結温度は９９０℃以上がよい。また、焼結温度が高すぎると、黒鉛が基地へ拡散して残留する黒鉛相が乏しくなるとともに、銅粉末が溶融して銅相が乏しくなるので、焼結温度は１０８０℃以下が適正である。なお、Ｓは、水素及び酸素と反応しやすいので、焼結雰囲気が酸化性のガスであると、原料粉末に導入したＳ成分が離脱して鉄系焼結合金中のＳ量が低下するため、焼結雰囲気は、非酸化性の雰囲気とする必要がある。また、露点が低い雰囲気を用いることが好ましい。
　本発明において、鉄系焼結含油軸受の製造方法は、上述のような鉄系焼結軸受の製造方法に従って鉄系焼結軸受を調製する工程と、潤滑油を鉄系焼結軸受に含浸する含浸工程とを有し、必要に応じて、含浸前の鉄系焼結軸受にサイジング、コイニング等の最終圧縮加工を施してもよい。潤滑油は、用途及び動作環境を勘案して各種潤滑油から適宜選択して使用することができ、例えば、鉱物油、合成炭化水素油、エステル油などから１種又は２種以上を組み合わせて使用して良い。 In the sintering process, if the sintering temperature is too low, the iron sulfide does not melt and the sulfide cannot be precipitated and dispersed in the base of the iron-based sintered alloy. Therefore, the sintering temperature is preferably 990 ° C. or higher. . Also, if the sintering temperature is too high, the graphite phase diffuses to the base and the remaining graphite phase becomes poor, and the copper powder melts and the copper phase becomes poor. . Since S easily reacts with hydrogen and oxygen, if the sintering atmosphere is an oxidizing gas, the S component introduced into the raw material powder is released and the amount of S in the iron-based sintered alloy decreases. The sintering atmosphere must be a non-oxidizing atmosphere. Further, it is preferable to use an atmosphere having a low dew point.
In the present invention, a method for producing an iron-based sintered oil-impregnated bearing includes a step of preparing an iron-based sintered bearing according to the method for producing an iron-based sintered bearing as described above, and impregnating the iron-based sintered bearing with a lubricating oil. An impregnation step, and if necessary, the iron-based sintered bearing before impregnation may be subjected to final compression processing such as sizing and coining. Lubricating oils can be used by appropriately selecting from various lubricating oils in consideration of the application and operating environment. For example, one or a combination of two or more of mineral oils, synthetic hydrocarbon oils, ester oils, etc. are used. You can do it.
［第１実施例］
　還元鉄粉末、扁平状の銅粉末、硫化鉄粉末、および、黒鉛粉末を用意し、表１に示す割合で添加し混合した原料粉末を用いて、成形圧力３００ＭＰａで、外径１６ｍｍ、内径１０ｍｍ、高さ１０ｍｍの円管形状に成形し、非酸化性ガス雰囲気中、１０００℃で焼結を行って試料番号０１～２０の軸受試料を作製した。尚、各試料番号について、以下の測定用に複数の焼結軸受試料を作製した。 [First embodiment]
Prepared reduced iron powder, flat copper powder, iron sulfide powder, and graphite powder, using raw material powder added and mixed in the ratio shown in Table 1, at a molding pressure of 300 MPa, an outer diameter of 16 mm, an inner diameter of 10 mm, It was molded into a circular tube shape with a height of 10 mm and sintered at 1000 ° C. in a non-oxidizing gas atmosphere to produce bearing samples of sample numbers 01 to 20. For each sample number, a plurality of sintered bearing samples were prepared for the following measurements.
　これらの軸受試料について、日本工業規格（ＪＩＳ）Ｚ２５０５に規定の金属焼結材料の焼結密度試験方法により測定した鉄系焼結合金の密度は、５．６～６．０Ｍｇ／ｍ３の範囲であった。 For these bearing samples, the density of the iron-based sintered alloy measured by the sintered density test method of the sintered metal material specified in Japanese Industrial Standard (JIS) Z2505 is in the range of 5.6 to 6.0 Mg / m 3 . Met.
　また、各試料番号の軸受試料について、日本工業規格（ＪＩＳ）Ｚ２５０７に規定の圧環強さ試験方法により各軸受試料の圧環強さを測定した。この結果を表１に併せて示す。 In addition, the crushing strength of each bearing sample was measured by the crushing strength test method specified in Japanese Industrial Standard (JIS) Z2507 for the bearing samples of each sample number. The results are also shown in Table 1.
　さらに、各試料番号の軸受試料について、潤滑油（鉱物油 粘度グレードＩＳＯ ＶＧ５６）を含浸し、焼結含有軸受の内径面における摩擦係数を測定した。摩擦係数の測定は、水平にしたモータの回転軸に炭素鋼Ｓ４５Ｃ製のシャフトを取り付けた。このシャフトを、ハウジングに取り付けた軸受に隙間を持たせて挿入し、ハウジングに鉛直方向の荷重を与えた状態でシャフトを回転させて行った。この試験において、周囲の温度は２５℃に保持し、シャフトの回転数を５００ｒｐｍ、負荷面圧を０．３ＭＰａに設定した。これらの結果を表１に併せて示す。 Furthermore, the bearing samples of each sample number were impregnated with lubricating oil (mineral oil viscosity viscosity ISO ISO VG56), and the friction coefficient on the inner diameter surface of the sintered bearing was measured. For measurement of the coefficient of friction, a shaft made of carbon steel S45C was attached to the rotating shaft of a horizontal motor. The shaft was inserted into a bearing attached to the housing with a gap, and the shaft was rotated while a vertical load was applied to the housing. In this test, the ambient temperature was maintained at 25 ° C., the rotation speed of the shaft was set to 500 rpm, and the load surface pressure was set to 0.3 MPa. These results are also shown in Table 1.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１の試料番号０１～０７の軸受試料を比較することで、Ｃｕ量の影響を調べることができる。表１より、Ｃｕを含まない試料番号０１の軸受試料は、軟質な銅相が形成されないことから、摩擦係数が大きい値となっている。これに対し、Ｃｕの添加量が０．５質量％の試料番号０２の軸受試料は、軟質な銅相が形成され、摩擦係数が０．２５まで低減できている。また、Ｃｕ量が増加するに従って摩擦係数が低減されることがわかる。これらのことから、Ｃｕ量が０．５～３質量％の範囲において、良好な摺動特性が得られることが確認された。この結果は、良好な潤滑油膜を形成しにくい摺動条件であっても対応可能であることを示す。 By comparing the bearing samples with sample numbers 01 to 07 in Table 1, the effect of the amount of Cu can be examined. From Table 1, the bearing sample No. 01 containing no Cu has a large friction coefficient because a soft copper phase is not formed. On the other hand, in the bearing sample of sample number 02 in which the added amount of Cu is 0.5% by mass, a soft copper phase is formed and the friction coefficient can be reduced to 0.25. Moreover, it turns out that a friction coefficient is reduced as the amount of Cu increases. From these results, it was confirmed that good sliding characteristics can be obtained when the amount of Cu is in the range of 0.5 to 3% by mass. This result shows that it is possible to cope with even a sliding condition in which it is difficult to form a good lubricating oil film.
　表１の試料番号０３、０８～１５の軸受試料を比較することで、Ｓ量の影響を調べることができる。表１より、Ｓを含まない試料番号０８の軸受試料は、硫化物相が形成されないことから、摩擦係数が大きい値となっている。これに対し、Ｓの添加量が０．３質量％の試料番号０９の軸受試料は、硫化物相が形成され、摩擦係数が０．２５まで低減できている。また、Ｓ量が増加するに従って摩擦係数が低減されていることがわかる。その一方で、Ｓ量が増加するに従って圧環強さは低下し、Ｓ量が２質量％を超える試料番号１５の軸受試料では圧環強さが１２０ＭＰａまで低下している。これらのことから、Ｓ量が０．３～２質量％の範囲において、摺動特性が良好で、且つ、機械的特性が高い鉄系焼結含油軸受を得られることが確認された。この結果は、良好な潤滑油膜を形成しにくい摺動条件であっても対応可能であることを示す。 By comparing bearing samples with sample numbers 03 and 08 to 15 in Table 1, the influence of the S amount can be examined. From Table 1, the bearing sample of sample number 08 not containing S has a large friction coefficient because no sulfide phase is formed. On the other hand, in the bearing sample of sample number 09 in which the addition amount of S is 0.3% by mass, a sulfide phase is formed and the friction coefficient can be reduced to 0.25. Moreover, it turns out that a friction coefficient is reduced as S amount increases. On the other hand, as the S amount increases, the crushing strength decreases, and in the bearing sample of Sample No. 15 where the S amount exceeds 2 mass%, the crushing strength decreases to 120 MPa. From these facts, it was confirmed that an iron-based sintered oil-impregnated bearing having good sliding characteristics and high mechanical characteristics can be obtained when the S content is in the range of 0.3 to 2% by mass. This result shows that it is possible to cope with even a sliding condition in which it is difficult to form a good lubricating oil film.
　表１の試料番号０３、１６～２１の軸受試料を比較することで、Ｃ量の影響を調べることができる。表１より、Ｃ量が０．５質量％である試料番号１６の軸受試料は、黒鉛相が乏しいことから、摩擦係数が大きい値となっている。これに対し、Ｃの添加量が１質量％の試料番号１７の軸受試料は、充分な量の黒鉛相が形成され、摩擦係数が０．２４まで低減できている。また、Ｃ量が増加するに従って摩擦係数が低減されていることがわかる。その一方で、Ｃ量が増加するに従って圧環強さは低下し、Ｃ量が５質量％を超える試料番号２１の軸受試料では圧環強さが１４０ＭＰａまで低下している。これらのことから、Ｃ量が０．５～５質量％の範囲において、摺動特性が良好で、且つ、機械的特性が高い鉄系焼結含油軸受を得られることが確認された。この結果は、良好な潤滑油膜を形成しにくい摺動条件であっても対応可能であることを示す。 The effect of the C amount can be investigated by comparing the bearing samples with sample numbers 03 and 16 to 21 in Table 1. From Table 1, the bearing sample No. 16 having a C amount of 0.5% by mass has a large coefficient of friction because the graphite phase is poor. On the other hand, in the bearing sample of Sample No. 17 in which the addition amount of C is 1% by mass, a sufficient amount of graphite phase is formed and the friction coefficient can be reduced to 0.24. It can also be seen that the friction coefficient is reduced as the amount of C increases. On the other hand, the crushing strength decreases as the C content increases, and the crushing strength decreases to 140 MPa in the bearing sample of Sample No. 21 in which the C content exceeds 5 mass%. From these facts, it was confirmed that an iron-based sintered oil-impregnated bearing having good sliding characteristics and high mechanical characteristics can be obtained when the C content is in the range of 0.5 to 5% by mass. This result shows that it is possible to cope with even a sliding condition in which it is difficult to form a good lubricating oil film.
［第２実施例］
　第１実施例の試料番号０３の原料粉末を用い、成形圧力を変えて成形を行い、第１実施例と同様の焼結条件で焼結を行って、試料番号２２～２９の軸受試料を作製した。これらの軸受試料につき、第１実施例と同様にして、各軸受試料の鉄系焼結合金の密度、圧環強さ、および摩擦係数を測定した。これらの結果、及び、第１実施例の試料番号０３における結果を併せて表２に示す。 [Second Embodiment]
Using the raw material powder of sample number 03 of the first example, molding is carried out at different molding pressures, and sintering is performed under the same sintering conditions as in the first example, thereby producing bearing samples of sample numbers 22 to 29 did. For these bearing samples, the density, crushing strength, and friction coefficient of the iron-based sintered alloy of each bearing sample were measured in the same manner as in the first example. These results and the results of Sample No. 03 of the first example are shown together in Table 2.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表２における試料番号０３、２２～２７を比較することで、鉄系焼結合金の密度の影響を調べることができる。摩擦係数は、密度５．０～７．２ｇ／ｃｍ３の範囲において０．２５以下に低減できている。気孔率が増加するに従って、軸受とシャフトの接触面積が低下して摩擦係数が低減されることが分かる。一方、圧環強さは、密度が低下するに従って低下し、密度５．０ｇ／ｃｍ３の試料番号２２の試料では１５０ＭＰａまで低下している。このことから、密度が５．２～７．２ｇ／ｃｍ３の範囲において、摺動特性が良好で、且つ、機械的特性が高い鉄系焼結含油軸受を得られることが確認された。この結果は、良好な潤滑油膜を形成しにくい摺動条件であっても対応可能であることを示す。 By comparing the sample numbers 03 and 22 to 27 in Table 2, the influence of the density of the iron-based sintered alloy can be examined. The coefficient of friction can be reduced to 0.25 or less in the density range of 5.0 to 7.2 g / cm 3 . It can be seen that as the porosity increases, the contact area between the bearing and the shaft decreases and the friction coefficient decreases. On the other hand, the crushing strength decreases as the density decreases. In the sample of Sample No. 22 having a density of 5.0 g / cm 3 , the crushing strength decreases to 150 MPa. From this, it was confirmed that an iron-based sintered oil-impregnated bearing having good sliding characteristics and high mechanical characteristics can be obtained in a density range of 5.2 to 7.2 g / cm 3 . This result shows that it is possible to cope with even a sliding condition in which it is difficult to form a good lubricating oil film.
　本発明における鉄系焼結含油軸受は、良好な潤滑油膜を形成しにくく、金属接触が発生しやすい摺動条件の下でも、良好な潤滑特性を発揮できる。複写機等の紙送りローラや、ヘッド駆動モータ等のような、正逆に回転する軸を支承し、正転、逆転それぞれの駆動時間が短い用途のための軸受として好適であり、又、スクロール式圧縮機等のような、固定子に対して偏心して回転する回転子の軸を支承する軸受等に好適である。 The iron-based sintered oil-impregnated bearing according to the present invention is less likely to form a good lubricating oil film, and can exhibit good lubricating properties even under sliding conditions where metal contact is likely to occur. It supports shafts that rotate in the forward and reverse directions, such as paper feed rollers for copiers, head drive motors, etc., and is suitable as a bearing for applications where the forward and reverse drive times are short. It is suitable for a bearing that supports the shaft of a rotor that rotates eccentrically with respect to the stator, such as a compressor.

Claims (6)

  1. 　軸の外周面を支持する軸受面を有し、気孔が分散する鉄系焼結合金で構成される鉄系焼結軸受と、前記気孔に含浸された潤滑油とを有する鉄系焼結含油軸受であって、
    　前記鉄系焼結合金の全体組成が、質量比で、Ｃｕ：０．５～３％、Ｃ：１～５％、Ｓ：０．３～２％、残部：Ｆｅおよび不可避不純物からなり、
    　前記鉄系焼結合金の密度が５．２～７．２ｇ／ｃｍ３であり、
    　前記鉄系焼結合金は、フェライト組織、パーライト組織、及び、フェライトとパーライトとの混合組織のうちの１つの金属組織を有する基地と、前記基地中に分散する銅相及び黒鉛相と、前記基地および前記銅相の少なくとも一方から析出して分散する硫化物相とを有する鉄系焼結含油軸受。     An iron-based sintered oil-impregnated bearing having a bearing surface that supports the outer peripheral surface of the shaft and comprising an iron-based sintered alloy in which pores are dispersed, and a lubricating oil impregnated in the pores Because
    The total composition of the iron-based sintered alloy consists of Cu: 0.5 to 3%, C: 1 to 5%, S: 0.3 to 2%, balance: Fe and inevitable impurities,
    The iron-based sintered alloy has a density of 5.2 to 7.2 g / cm 3 ;
    The iron-based sintered alloy includes a matrix having one of a ferrite structure, a pearlite structure, and a mixed structure of ferrite and pearlite, a copper phase and a graphite phase dispersed in the matrix, and the base And an iron-based sintered oil-impregnated bearing having a sulfide phase precipitated and dispersed from at least one of the copper phases.
  2. 　前記硫化物相が、前記基地および前記銅相の結晶粒界および結晶粒内に析出して分散する請求項１に記載の鉄系焼結含油軸受。 The iron-based sintered oil-impregnated bearing according to claim 1, wherein the sulfide phase is precipitated and dispersed in crystal boundaries and crystal grains of the matrix and the copper phase.
  3. 　前記硫化物は、硫化鉄および硫化銅が主体である請求項１または２に記載の鉄系焼結含油軸受。 The iron-based sintered oil-impregnated bearing according to claim 1 or 2, wherein the sulfide is mainly composed of iron sulfide and copper sulfide.
  4. 　前記金属組織において、前記硫化物相が、金属組織の断面を観察した時に気孔を含む断面の面積に対して０．９～６％の面積率で前記金属組織に分散している請求項１～３のいずれか一項に記載の鉄系焼結含油軸受。 In the metal structure, the sulfide phase is dispersed in the metal structure at an area ratio of 0.9 to 6% with respect to an area of a cross section including pores when a cross section of the metal structure is observed. 4. The iron-based sintered oil-impregnated bearing according to claim 3.
  5. 　前記硫化物相は、最大粒径が５０μｍ以下の粒状である請求項１～４のいずれか一項に記載の鉄系焼結含油軸受。 The iron-based sintered oil-impregnated bearing according to any one of claims 1 to 4, wherein the sulfide phase is granular having a maximum particle size of 50 µm or less.
  6. 　前記軸受面に分散する銅相および硫化銅相は、軸受面全体に対して５～２０％の面積率で分散している請求項１～５のいずれか一項に記載の鉄系焼結含油軸受。 The iron-based sintered oil impregnation according to any one of claims 1 to 5, wherein the copper phase and the copper sulfide phase dispersed on the bearing surface are dispersed at an area ratio of 5 to 20% with respect to the entire bearing surface. bearing.
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* Cited by examiner, † Cited by third party
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JP2019065323A (en) * 2017-09-29 2019-04-25 日立化成株式会社 Iron-based sintered shaft bearing, and iron-based sintered oil-containing shaft bearing

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CN111139427B (en) * 2020-01-14 2022-03-11 合肥波林新材料股份有限公司 Iron-based sintered sulfur vapor material, shaft sleeve and preparation method thereof

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013076152A (en) * 2011-09-30 2013-04-25 Hitachi Powdered Metals Co Ltd Iron-based sintered sliding member and method for producing the same
JP2014066271A (en) * 2012-09-25 2014-04-17 Hitachi Powdered Metals Co Ltd Plain bearing assembly
JP2014177658A (en) * 2013-03-13 2014-09-25 Hitachi Chemical Co Ltd Iron-based sintered sliding member and production method thereof

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013076152A (en) * 2011-09-30 2013-04-25 Hitachi Powdered Metals Co Ltd Iron-based sintered sliding member and method for producing the same
JP2014066271A (en) * 2012-09-25 2014-04-17 Hitachi Powdered Metals Co Ltd Plain bearing assembly
JP2014177658A (en) * 2013-03-13 2014-09-25 Hitachi Chemical Co Ltd Iron-based sintered sliding member and production method thereof

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2019065323A (en) * 2017-09-29 2019-04-25 日立化成株式会社 Iron-based sintered shaft bearing, and iron-based sintered oil-containing shaft bearing
JP7024291B2 (en) 2017-09-29 2022-02-24 昭和電工マテリアルズ株式会社 Iron-based sintered bearings and iron-based sintered oil-impregnated bearings

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