GB2216543A - Sintered oil retaining bearing - Google Patents

Sintered oil retaining bearing Download PDF

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GB2216543A
GB2216543A GB8905402A GB8905402A GB2216543A GB 2216543 A GB2216543 A GB 2216543A GB 8905402 A GB8905402 A GB 8905402A GB 8905402 A GB8905402 A GB 8905402A GB 2216543 A GB2216543 A GB 2216543A
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copper
weight
powder
alloy
iron
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GB2216543B (en
GB8905402D0 (en
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Isamu Kikuchi
Masanori Kikuchi
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    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C33/00Making ferrous alloys
    • C22C33/02Making ferrous alloys by powder metallurgy
    • C22C33/0257Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements
    • C22C33/0278Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements with at least one alloying element having a minimum content above 5%
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22FWORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/17Metallic particles coated with metal
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C33/00Making ferrous alloys
    • C22C33/02Making ferrous alloys by powder metallurgy
    • C22C33/0207Using a mixture of prealloyed powders or a master alloy
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C9/00Alloys based on copper
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16CSHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C33/00Parts of bearings; Special methods for making bearings or parts thereof
    • F16C33/02Parts of sliding-contact bearings
    • F16C33/04Brasses; Bushes; Linings
    • F16C33/06Sliding surface mainly made of metal
    • F16C33/10Construction relative to lubrication
    • F16C33/1025Construction relative to lubrication with liquid, e.g. oil, as lubricant
    • F16C33/103Construction relative to lubrication with liquid, e.g. oil, as lubricant retained in or near the bearing
    • F16C33/104Construction relative to lubrication with liquid, e.g. oil, as lubricant retained in or near the bearing in a porous body, e.g. oil impregnated sintered sleeve
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16CSHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C33/00Parts of bearings; Special methods for making bearings or parts thereof
    • F16C33/02Parts of sliding-contact bearings
    • F16C33/04Brasses; Bushes; Linings
    • F16C33/06Sliding surface mainly made of metal
    • F16C33/12Structural composition; Use of special materials or surface treatments, e.g. for rust-proofing
    • F16C33/121Use of special materials
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22FWORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F2998/00Supplementary information concerning processes or compositions relating to powder metallurgy

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Sliding-Contact Bearings (AREA)
  • Powder Metallurgy (AREA)

Abstract

A sintered alloy for an oil-retaining bearing is characterised in that the sintered alloy is produced by sintering a green compact comprising particles of iron coated with copper or copper-base alloys, which consists of 20-55% by weight of iron, 30-75% by weight of copper, 2-12% by weight of tin, 2.5-9% by weight of lead and has an open porosity of from 15 to 28% by volume.

Description

Sintered Alloy for Oil-Retaining Bearing and Method for Manufacturing the Sintered Alloy The present invention relates to a sintered alloy for an oil-retaining bearing and a method for manufacturing the sintered alloy, and more particularly to a sintered alloy and a method for manufacturing the same which is suitable for the bearings of audio instruments and the like. The sintered alloy being excellent in adaptability to the counterpart of the bearing, causing relatively little increase in temperature when it is driving, because of the low friction coefficient, and being excellent in mechanical strength.
Sintered alloys have been widely employed in oil-retaining bearings and serve as important components in most appliances. In the national standards in Japan called Japanese Industrial Standards (JIS) are standardized various kinds of industrial appliances. These bearings are made of various kinds of alloys for example, iron alloys, iron-copper alloys, iron-carbon alloys, iron-copper-carbon alloys, ironcopper-lead alloys, bronze alloys, copper alloys, leadbronze alloys and like alloys.
Incidentally, for example, Japanese Patent Laid-Open 56-51554 discloses a green compact essentially composed of an iron powder and a brass powder, which compact is subjected to a sintering process to produce a sintered alloy.
The above-mentioned conventional oil-retaining bearing, which is made of an alloy a main component of which is iron is excellent in mechanical strength.
Therefore, it can serve as a heavy-duty bearing.
However, such a conventional bearing has a large friction coefficient so disadvantegeously causing increased abrasion in the counterpart of the bearing, and also has poor corrosion resistance.
In order to resolve the above disadvantages of conventional bearings, a copper-base sintered alloy for oil-retaining bearing has been proposed. However, such bearings made of copper-base alloy are expensive and have poor mechanical strength.
In order to accommodate these material properties of the above conventional bearings, another conventional bearing has been proposed, which bearing is made a sintered alloy a green compact of which is essentially composed of an iron powder, a copper powder, and at least one of additional metal powders such as bronze powders, brass powders, lead powders and German-silver powders. However, the sintered alloy of this other conventional bearing suffers from segregations of the additional metal powders. In addition, the bearing made of such sintered alloy has the same disadvantages as bearings made of iron-base alloy when the proportion of the iron powder is relatively large in the green compact of the alloy.On the other hand, when the proportion of the copper powder or the copper-base alloy powder is relatively large, the bearing made of such alloy is expensive and suffers from the same disadvantages as bearings made of copper-base alloy.
Incidentally, the conventional powder mixture mentioned-above is generally poor in ease in compaction so that the mixture must be compacted under a relatively large pressure or there must be included therein a suitable powdered solid lubricant for smoothly conducting the compaction process of the mixture. In cases where the powder mixture includes a suitable powdered solid lubricant mixed with the mixture, the alloy is relatively poor in mechanical strength, and the dies have limited life, Fig. 3 is a photomicrographic illustration showing the microstructure of a conventional sintered iron-copper alloy a green compact of which includes 70% by weight of an iron powder and 30% by weight of a copper powder.As is clear from Fig. 3, iron particles (1) and copper particles (2) are uniformly mixed with each other, and the ratio of exposed area is in proportion to the ratio of powders of the mixture.
Nowadays, one of the most important usages of the oil-retaining bearing is audio appliances, for example, capstan axis of tape player or video tape deck, which is installed inartial rotating fly wheel and rotating from high speed rotation to low speed rotation. In this condition, good mechanical strength, ensuring the same axis angle position, low friction coefficient, and excellent adaptability to the counterpart of axis are needed to effectively prevent wow, noise and other problems. But is is very difficult to achieve these properties effectively.
It is an object of the present invention to provide a sintered alloy for an oil-retaining bearing and a method for manufacturing the same which is suitable for the bearings of audio instruments, being excellent in adaptability to the counterpart of the bearing, causing relatively little increase in temperature because of its low friction coefficient, and having excellent mechanical strength.
According to the present invention, these disadvantages inherent in the above conventional sintered alloys are eliminated by employing the following sintered alloys for oil-retaining bearings and method for manufacturing the sintered alloys: 1. A sintered alloy suitable as a material for an oil-retaining bearing, characterized in that said sintered alloy; is produced by sintering a green compact in which the entire peripheral surface of each particles of iron is coated with copper or copper-base alloys; consists of 20-55% by weight of iron, 30-75% by weight of copper, 2-i2% by weight of tin, 2.5-9% by weight of lead; and has an open porosity ranging from 15% by volume to 28% by volume.
2. A method for manufacturing a sintered alloy suitable for an oil-retaining~bearing, comprising the steps of: Mixing a predetermined amount of an iron powder with a powder of copper metal to prepare a first powder mixture in which said iron powder is coated with 25-60% by weight of said copper powder; further mixing 100 parts by weight of said first powder mixture with 10-150 parts by weight of powder of tin-lead alloy and/or copper-tin-lead alloy to prepare a second powder mixture; compacting said second powder mixture into a green compact ; sintering said green compact in 500780 C to produce a sintered alloy ; and sizing said sintered alloy to produce an alloy product.
Additional object and features of the present invention will become apparent from the following description of the preferred embodiments of the present invention, which will be made with reference to the accompanying drawings in which: Fig. 1 is an enlarged sectional view of a spherical iron particle coated with a copper powder coating formed according to the present invention; Fig. 2 is an enlarged sectional view of an irregular-shape iron particle coated with a copper powder coating formed according to the present invention; and Fig. 3 is a photomicrographic illustration of a conventional sintered alloy the contents of iron and copper are in the ratio of 70 to 30.
Referring now to the drawings, there are illustrated: an iron particle 1; a copper particle 2; a copper coating 2a; and a fine particle 3.
According to the present, each iron particle 1 is coated with copper in preparation of a starting powder mixture which is compacted into a green compact from which a sintered alloy is produced through a sintering process. A copper coating on each iron particle 1 is produced through one of the methods electroplating process, hot dipping process, electroless plating process, or dry plating process. As shown in Fig. 1 and 2, the iron particle 1 is entirely coated with copper coating 2a, and is further coated partly with fine powder 3 which makes an irregular surface on the iron particles.
An electric current density and operating time of which above process are controlled to produce a desired copper coating on each of the iron particles 1.
The sintered alloy of the present invention contains 25-60% by weight of copper coating, preferably 28-45% by weight of such copper metal coating.
In Fig. 1 and 2 it is shown that each of the iron particles 1 is coated with copper coating 2a.
More than 95% of the surface of each iron particle 1 is effectively coated with copper. As shown from the photomicrographic illustration, the copper coating 2a has an irregular surface 3 made of copper powders, and so fine as to make their compaction process easy. The irregular surfaces 3 will never allow segregation and other defects in case that making mixture of iron powder and copper powder.
Incidentally, in the present invention, although the iron particles are not specified in size, it is possible to employ iron particles in wider particle size range than a conventional particle size of 100 mesh employed in manufacturing iron-base sintered alloys. Namely, even when relatively fine iron particles are employed in the present invention, such iron particles are coated with copper so as to be expanded in their diameter, which makes it possible to easily treat such fine iron particles coated with copper in the same manner as that of the conventionalsize iron particles. In addition, due to the presence of the copper coating on each of the iron particles such iron particles coated with copper are excellent in easiness in compaction, which makes it possible to normally or easily compact oversize iron particles in the same manner as that of the conventional-size iron particles.
Tin-lead alloy powder of the present invention consists of 10-63% by weight of tin and the rest is lead, and copper-tin-lead alloy of the present invention is consisting of 5-1 2% preferably 5-86 by weight of tin, 1-15% preferably 2-8% by weight of lead, and the rest is copper. Soft soldering like properties are obtained by alloying tin with lead, and further alloyed with copper to make the alloy product being excellent adaptability to copper coating iron particles. In this alloy material, in case it is consisting of less than 2% by weight of tin and less than 2.5% by weight of lead, above properties can not be obtained.On the other hand, in case it is consisting of more than 12% by weight of tin, and/or more than 7% by weight of lead, a process for sintering iron particles which coated with copper powder is apt to be relatively not suitable.
Mixing proportion of copper coated iron powder and copper-tin-lead alloy powder mentioned above is preferably mixing 100 parts by weight of copper coated iron powder based on 10-150 parts by weight of copperin-lead alloy powder.
In general, the green compact containing the iron particles coated with copper has an open porosity ranging about 23% by volume to about 38% by volume, specifically ranging from about 26% by volume to about 32% by volume. In case the open porosity of the green compact is less than 26% by volume specifically less than 23% by volume, the sintered alloy product made from green compact is used for the oil-retaining bearing, it is impossible for the sintered alloy produced from such green compact to reserve a margin for sizing process and to have an open porosity for oil-impregnation process. In contrast with this, in case than an open porosity of the green compact is more than 32% by volume, specifically more than 38% by volume, the green compact suffers from its poor mechanical strength which increases damages of the green compact during handling and sintering operations thereof.
Incidentally, in the green compact of the present invention the iron particles contained therein have the same coating proportions with each other.
However, according to the present invention, it is also possible to employ a green compact in which the coating proportions of the iron particles are different from each other. For example, according to the present invention, the green compact may be composed of: iron particles having a copper-coating proportion of 10 wt.%; iron particles having a copper-coating proportion of 20 wt.X; and iron particles having a copper-coating proportion of 30 wt.%. They are mixed with each other and further mixed copper alloy powder of the present invention.
The green compact of the present invention is generally compacted with the pressure about 2-3 ton/cm2 by the metal pattern. This compacting pressure is 7085% comparing with the conventional compacting pressure of the iron powder.
In general, the green compact is sintered at a sintering temperature of from 500 to 78OOC preferably 550 to 7000C and sintering time for about 30 to 60 minutes in a reducing atmosphere or in an inert atmosphere.
The thus sintered compact of alloy is then subjected to a sizing operation to produce a desired alloy product having a predetermined size and a predetermined porosity. The sintered alloy has a sizing margin the proportion of which is about 20 to 35X based on the open porosity of the green compact.
The sintered alloy is subjected to sizing to produce an alloy product wich has an open porosity of from 15 to 18X by volume. In this case when the open porosity of the alloy product is less than 15X by volume, is is impossible to conduct a successful oil-impregnation operation of the alloy product suitable as a material for an oil-retaining bearing. On the other hand, when the open porosity of the alloy product is more than 28% by volume, the alloy product suffers from poor mechanical strength. Preferably, the alloy product has an open porosity of from 18 to 23% by volume, which makes the alloy product good in mechanical strength and oil-impregnation properties.
A solid lubricant such as graphite and molybdenum disulfide is mixed with the other starting powders in a pulverized condition to prepare a powder mixture which is compacted into the green compact.
However, the pulverized solid lubricant such as graphite is smaller in specific gravity than any of the remaining starting powders of iron, German-silver and bronze so that such lubricant powder tends to float on the powder mixture so as to segregate therefrom during transportation, handling in press hopper, and compaction treatment of the mixture, which makes it difficult to uniformly mix the lubricant powder with the remaining starting powders. In order to resolve such segregation problem, the solid lubricant such as graphite is mixed with the remaining starting powders in a granulated condition, the lubricant assuming a fine-powder shape removed, which is found effective against the segregation problem. Namely, the size of a commercially available graphite powder is within the range of from 1 to 30 microns, or from 1 to 50 microns.
In contrast with this, a preferable size of the graphite powder employed in the present invention is with the range of from 10 to 150 microns, more preferably within the range of from 20 to 100 microns in which a graphite powder up to 10 microns, preferably up to 20 microns in size is removed, whereby the graphite powder may be uniformly mixed with the other starting powders to resolve the above segregation problem. Separation of the graphite powder up to 10 microns, preferably up to 20 microns in size is effectively conducted in a liquid which prevents the graphite powder from producing dust. And in case a solid lubricant is coated with copper powder, it is possible to strip off the coating though the compacting process and sizing process.
Effect of the present invention will be now described hereinbelow.
Due to the sintered alloy of the present invention being comprised of 20% by weight of iron particle, sintered alloy of the present invention is excellent in mechanical strength, specifically to pressure resistance, and in case it is employed in oilretaining bearing it will effectively ensured the same angle of the rotary axis.
In case the sintered alloy comprising less than 55% by weight of iron, each of copper, tin and lead can preferably be comprised, and sintered alloy of this invention being obtained the adaptability to the counterpart of bearing, low friction coefficient and keep the bearing relatively low temperature range.
In order to effectively coat the iron particles of the present invention and obtain the corrosion resistance, sintered alloy of this invention is comprising more than 306 by weight of copper. In order to effectively comprising iron, tin and lead, less than 706 by weight of copper should be comprised.
In order to obtain an excellent adaptability to counterpart of the bearing and low friction coefficient, sintered alloy of this invention should be comprising of more than 2% by weight of tin, and more than 2.56 by weight of lead. Costs of the products are kept low by restraining the upper limit of tin of 12% by weight, and restraining the upper'limit of lead of 9% by weight, specifically of 7% by weight. These limits make a suitable metals balance between iron, copper, tin and lead, and due to these limits, products of the present invention obtain above properties sufficiently.
In order to realize the preferred oilimpregnation of bearing and lubricating operation, the alloy product of the-present invention has an open porosity of more than 15% by volume. Due to restricting the upper limit of the open porosity of 28% by volume, the alloy product of the present invention has a good mechanical strength.
In order to coat iron particles effectively, to obtain good corrosion resistance and easy compacting operation, iron particles are coated with copper metal powders of more than 25% in proportion by weight. Due to restraining the upper limit of coating copper powders of 60% by weight, tin and lead effectively being comprised to produce a suitable alloy of the present invention.
Each of compacting iron particles coated with copper powders are obtained mechanical strength, and the alloy product of the present invention, when it is employed to bearing, the angle of the bearing axis is firmly fixed, good adaptability to the counterpart of the bearing, and sufficient mechanical strength can be obtained because of properties of mixed metals. So as to considerable iron powders are comprised in the present invention, the cost of the alloy product of the present invention is kept relatively low.
As for the iron particles coated with copper according to the present invention, each of the iron particles are further coated with powders of tin-lead alloy or copper-tin-lead alloy, and when the alloy product of the present invention is employed in bearing material, more excellent adaptability to the counterpart of the bearing, low friction coefficient of the alloy, and more excellent thermal conductivity through sintering conducted relatively at a low temperature can be obtained. Tin-lead-copper alloy powders improving the sintering property of the iron particles coated with copper powders, and the green compact of the present invention preferably sintered at a relatively low sintering temperature of from 450 to 750 C.
In cases where the amount of tin-lead-copper alloy powder is less than 10 parts by weight based on 100 parts by weight of copper coated iron particles, it is possible to obtain above effects. On the other hand, when the amount of tin-lead-copper alloy powder is more than 150 parts by weight, the cost of the product of sintered alloy increases while a mechanical strength effect is not expected.
Copper powder coating formed on iron particles, and further coating formed by tin-lead-copper alloy powders will make the compacting process easy.
EXAMPLE Minus 100-mesh iron particles were copper plated to prepare a copper-coated iron particles which have a 40% by weight of copper coating. Tin-leadcopper alloy powder comprising 5% by weight of tin and 5% by weight of lead, and molybdenum disulfide (MoS2) powder coated slightly with tin-lead alloy powder and copper powder, including 63% by weight of tin and 37% by weight of lead prepared, and the powders were mixed as shown in Table 1, from No. 1 to No. 7.
TABLE 1
Testing Number No. 1 No. 2 No. 3 No. 4 No. 5 No. 6 No. 7 40% Copper plated iron Powder 50 % 60 % 40 % 50 % 90 % 85 % 86 % 50% Tin - 5% Lead - Copper alloy Power 45 % 35 % 60 % 40 % - - Cooper coated MoSz Powder - - - 4 % - - 4 % 63% Tin - 37% Lead - Copper alloy Powder 5 % 5 % - 6 % 10 % 15 % 10 % Table 2 shows compositions and theorical specific gravities of No. 1 to No. 7 shown in Table 1. TABLE 2
Testing Number No. 1 No. 2 No. 3 No. 4 No. 5 No. 6 No. 7 Fe 30.00 % 36.00 % 24.00 % 30.00 % 54.00 % 51.00 % 51.60 % Cu 60.50 % 55.50 % 70.; ;00 % 58.00 % 36.00 % 34.00 % 36.40 % Sn 5.40 % 4.90 % 3.00 % 5.78 % 6.30 % 9.45 % 6.30 % Pb 4.10 % 3.60 % 3.00 % 4.22 % 3.70 % 5.55 % 3.70 % MoSz - - - 2.00 % - - 2.00 % Therical 8.565 8.479 8.638 8.714 8.280 8.287 8.189 Specific Granuties Each of these powders are compacted to make the products about 6.02mm in outer diameter, about 12.07mm in inner diameter and about 10mm in length.These products are further sintered at a sintering temperature of 650 C by the continous sintering fireplace at a speed of 7mm/minutes. Table 3 shows compact densities, densities after sintering, outer diameters, changes in outer diameters through sintering, squeezing points and hardness of these products.
TABLE 3
Comfact Density Open Outer- Change in Outer- Squeezing Hardness density after Porosity diameter diameter through point Sintering Sintering (HRH) Average 5.954 6.080 28.86 12.007 -0.522 14.34 36.4 maximum 5.970 6.100 29.20 12.020 - 0.414 14.87 40.0 minimum 5.940 6.060 28.60 12.000 - 0.580 13.65 31.0 Difference 0.030 0.040 0.60 0.200 0.166 1.22 9.0 Av. 5.918 6.064 28.48 11.990 - 0.663 15.11 42.0 flax. 5.930 6.090 28.60 12.000 -0.580 15.53 45.0 Min. 5.900 6.030 28.30 11.980 - 0.746 14.13 38.0 Dif. 0.030 0.060 0.30 0.020 0.166 1.40 7.0 Av. 6.042 6.184 28.42 12.006 -0.530 13.97 28.4 Max. 6.050 6.220 28.70 12.010 - 0.497 14.12 31.0 mien. 6.030 6.160 28.00 12.000 - 0.580 13.83 26.0 Dif. 0.020 0.060 0.70 0.010 0.083 0.29 5.0 Av. 6.082 6.188 27.48 12.017 - 0.439 15.22 48.8 Max. 6.100 6.200. 27.80 12.020 - 0.414 15.56 50.0 Min. 6.070 - 6.170 27.40 12.010 - 0.497 14.95 48.0 Dif. 0.030 0.030 0.40 0.010 0.083 0.61 2.0 Av. 5.784 5.984 27.48 11.948 - 1.011 12.44 55.6 Max. 5.850 6.070 28.90 12.000 - 0.580 13.17 60.0 Min. 5.740 5.860 26.50 11.895 - 1.450 11.43 52.0 Dif. 0.110 0.210 2.40 0.105 0.870 1.74 8.0 Av. 5.826 6.148 25.86 11.874 - 1.624 12.51 j 73.0 Max 5.850 6.270 26.70 11.940 -1.077 12.99 81.0 Min. 5.800 6.070 24.50 11.810 -2.154 12.18 64.0 Dif. 0.050 0.200 2.20 0.130 1.077 0.81 Av. 5.696 5.846 29.42 11.988 -0.679 12.64 53.6 Max. 5.710 5.860 29.60 11.990 -0.683 12.91 57.0 mien. 5.680 5.840 - 29.20 11.980 - 0.746 12.27 Dif. 0.030 0.020 0.40 0.010 0.083 0.64 5.0 UNIT g/cc g/cc Vol% mm % Kgf/mm deg.
These sintered products are further sized to make the oil-retaining bearings of inner diameter of about 0.08mm, open porosity of about 25% by volume, and outer diameter of about 12.00mm.
These bearings of the present invention were tested for temperature increase by using them for rotary axis rotating at 1500 rpm or at 5000 rpm. 40 minutes from the start of the test (in general, temperature of bearings increased for 30 minutes, after 30 minutes there was no temperature increase) temperature increase was 15-16 C for the 1500 rpm test, and 24-25 0C for the 5000 rpm test. The results of these tests illustrate the advantageous property of bearings of the present invention.
Inventors of the present invention have examined sintering property of said testing powders No. 1 to No. 7, through the batch sintering at a sintering temperature of 6000C, and continous sintering at temperatures of 650 0C and 7000C for 1 hour. Results of these examinations are almost the same as the results described in Table 3 except changes of squeezing point of 2-6 kg/mm2, and hardness of 2-25 HRH.
As described above, in the sintered alloy of the present invention, copper coating formed on the iron particles so as to prevent the iron from lower friction coefficient of the alloy, and improve the alloy in its adaptability to the counterpart or journal when the alloy serves as a bearing. In addition, the sintered alloy of the present invention is also excellent in thermal conductivity and may be produced through sintering conducted at a relatively low sintering temperature. Namely, it is possible to easy produce the sintered alloy of the present invention.
Consequently, we believe that the present invention contributes much to industry.

Claims (2)

1. A sintered alloy suitable as a material for an oil-retaining bearing characterized in that the sintered alloy is produced by sintering a green compact in which the entire peripheral surface of each of particles of iron is coated with copper or copper-base alloys; consist-s of 20-55% by weight of iron, 30-75% by weight of copper, 2-12% by weight of tin, 2.5-9% by weight of lead; and has an open porosity ranging from 15% by volume to 28% by volume.
2. A method for manufacturing a sintered alloy suitable for an oil-retaining bearing, comprising the steps of: mixing a predetermined amount of an iron powder with a powder of copper metal to prepare a first powder mixture in which said iron powder is coated with 25-60% by weight of said copper powder; further mixing 100 parts by weight of said first powder mixture with 10150 parts by weight of powder of tin lead alloy and/or copper-tin-lead alloy to prepare a second powder mixture; compacting said second powder mixture into a green compact; sintering said green compact in 500-780 0C to produce a sintered alloy; and sizing said sintered alloy to produce an alloy product.
GB8905402A 1988-03-09 1989-03-09 Sintered alloy for oil-retaining bearing and method for manufacturing the sintered alloy Expired - Lifetime GB2216543B (en)

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JP63053694A JP2553374B2 (en) 1988-03-09 1988-03-09 Sintered alloy material for oil-impregnated bearing and manufacturing method thereof

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GB8905402D0 GB8905402D0 (en) 1989-04-19
GB2216543A true GB2216543A (en) 1989-10-11
GB2216543B GB2216543B (en) 1991-04-24

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Publication number Priority date Publication date Assignee Title
WO2000007773A1 (en) * 1998-08-03 2000-02-17 Tyrolit Schleifmittelwerke Swarovski Kg Abrasive tool
WO2000036169A1 (en) * 1998-12-16 2000-06-22 Victorian Rail Track Low resistivity materials with improved wear performance for electrical current transfer and methods for preparing same
US7553445B2 (en) * 2003-09-10 2009-06-30 Hitachi Powdered Metals Co., Ltd. Manufacturing processes of sintered alloy and oil-impregnated sintered bearing
US20110206305A1 (en) * 2008-10-29 2011-08-25 Ntn Corporation Sintered bearing

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH03150330A (en) * 1989-11-07 1991-06-26 Sankyo Seiki Mfg Co Ltd Manufacture of bearing
KR100455261B1 (en) * 2002-07-04 2004-11-06 삼성전기주식회사 Sintered oilless bearing and manufacturing method thereof
JP7143356B2 (en) * 2020-03-10 2022-09-28 大同メタル工業株式会社 Sliding member, its manufacturing method, and hard material manufacturing method

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5129486A (en) * 1974-09-02 1976-03-12 Otsuka Pharma Co Ltd * 33 arukiruamino 22 hidorokishi * purohokishi 3 44 jihidorokarubosuchirirujudotai no seizoho
JPS5433812A (en) * 1977-08-22 1979-03-12 Hitachi Ltd Process for producing high-density sintered material
JPS57169064A (en) * 1981-04-10 1982-10-18 Hitachi Powdered Metals Co Ltd Low wear sintered sliding material containing oil

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000007773A1 (en) * 1998-08-03 2000-02-17 Tyrolit Schleifmittelwerke Swarovski Kg Abrasive tool
US6338907B1 (en) 1998-08-03 2002-01-15 Tyrolit Schleifmittelwerke Swarovski K.G. Abrasive tool
WO2000036169A1 (en) * 1998-12-16 2000-06-22 Victorian Rail Track Low resistivity materials with improved wear performance for electrical current transfer and methods for preparing same
US6679933B1 (en) 1998-12-16 2004-01-20 Victorian Rail Track Low resistivity materials with improved wear performance for electrical current transfer and methods for preparing same
US7553445B2 (en) * 2003-09-10 2009-06-30 Hitachi Powdered Metals Co., Ltd. Manufacturing processes of sintered alloy and oil-impregnated sintered bearing
US20110206305A1 (en) * 2008-10-29 2011-08-25 Ntn Corporation Sintered bearing

Also Published As

Publication number Publication date
GB2216543B (en) 1991-04-24
JPH01230740A (en) 1989-09-14
JP2553374B2 (en) 1996-11-13
GB8905402D0 (en) 1989-04-19
HK76591A (en) 1991-10-11

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