JP6760807B2 - Copper-based sintered alloy oil-impregnated bearing - Google Patents

Description

The present invention relates to a copper-based sintered alloy oil-impregnated bearing, particularly a copper-based sintered alloy oil-impregnated bearing that exhibits excellent friction and wear characteristics under high load conditions.

Conventionally, bronze (copper-tin alloy) type and phosphorus bronze (copper-), which have the advantages of having good initial compatibility with friction and suppressing seizure as a sliding part material for automobiles and general industrial machines. Tin-phosphorus alloys) or bronze nickel (copper-tin-nickel alloys) -based copper-based sintered alloys are widely used. However, copper-tin alloy-based and copper-tin-phosphorus alloy-based sintered alloys have low strength and cannot be used in applications where high loads are applied, and a matrix of these sintered alloys (copper-tin alloy). In the matrix), hard particles having a hardness higher than that of the matrix, for example, metallic particles such as molybdenum (Mo) and tungsten (W) or silica (SiO ₂ ), alumina (Al ₂ O ₃ ) and silicon carbide (SiC). The ceramic hard particles such as the above are dispersed and contained to improve the strength, load resistance, abrasion resistance or seizure resistance.

However, since metal-based hard particles such as molybdenum and tungsten have lower hardness than ceramic-based hard particles, the effect of scraping off the copper alloy adhering to the surface of the mating material is weak, and metals such as molybdenum and tungsten have a weak effect. Since the hard particles are metals, there is a problem that they are relatively easy to adhere to a mating material made of iron alloy steel (steel). Further, since the copper-based sintered alloy containing dispersed ceramic-based hard particles such as silica, alumina, and silicon carbide receives a load at the hard particle portion, the shearing force generated at the boundary between the copper-based matrix and the hard particles causes the shearing force. Hard particles fall off from the copper-based matrix and intervene in the sliding interface, causing abstract wear and attacking not only the mating material (rotary shaft, etc.) but also the copper-based sintered alloy itself, and the mating material and copper-based baking There is a risk that the binder will wear out and seizure will occur.

On the other hand, the copper-tin-nickel alloy-based sintered alloy contains a large amount of nickel component, so that the strength is higher than that of the copper-tin alloy-based or copper-tin-phosphorus alloy-based sintered alloy. In applications where a high load acts, there is a problem that the wear resistance is inferior.

In order to improve the wear resistance in applications where this high load acts, for example, Patent Document 1, Patent Document 2, Patent Document 3, Patent Document 4, and the like include copper-nickel-tin alloy-based sintered alloys. Proposed.

Japanese Unexamined Patent Publication No. 2004-68074 Japanese Unexamined Patent Publication No. 2008-07996 Japanese Unexamined Patent Publication No. 2016-53200 Japanese Unexamined Patent Publication No. 57-101603

By the way, in the copper-nickel-tin alloy-based sintered alloys described in Patent Documents 1 to 4, the alloyed copper powder, nickel powder, copper-nickel alloy powder, tin powder, and copper-nickel-tin Since the alloy powder and the copper-phosphorus alloy powder are selected as the raw material powder so as to have the desired composition, mixed and sintered, each raw material powder is easily segregated in the mixed powder, and a homogeneous sintered alloy is obtained. There is a problem that it is difficult to obtain.

As a result of diligent studies in view of the above circumstances, the present inventors have focused on copper, nickel, tin and phosphorus, which are the compositions of the sintered alloy layer described in Patent Document 4, which exhibit excellent friction and wear characteristics. When a metal was melted as a raw metal to prepare a molten metal and powder particles prepared by powdering the molten metal by a molten metal spraying method (atomization method), particularly a water atomizing method, were observed, the powder particles were copper-nickel-. It exhibits a metal structure containing a matrix phase containing a tin alloy and a nickel-phosphorus alloy phase that is finely diffused and solidified (crystallized) in the matrix phase, and the nickel-phosphorus alloy phase is more than the matrix phase. It was found that the hardness is high, and segregation of metal components can be suppressed by using this water atomizing powder, and the sintered alloy obtained by using the water atomizing powder disperses metal-based and ceramic-based hard particles. It was found that it exhibits excellent wear resistance as well as the contained copper-based sintered alloy.

The present invention has been made based on the above findings, and an object of the present invention is a copper-based sintered alloy oil-impregnated bearing that can support a high load and exhibits excellent wear resistance even if a high load is supported. Is to provide.

The copper-based sintered alloy oil-impregnated bearing of the present invention contains nickel, tin and phosphorus, as well as water-atomized copper-based alloy powder containing copper as a main component, graphite powder, and lubricating oil, and nickel 9 to 38. A matrix phase containing 8% by mass, 3.6 to 9.7% by mass of tin, 0.45 to 4.9% by mass of phosphorus and 3 to 10% by mass of graphite, and a copper-nickel-tin alloy and this matrix phase. It has a metallographic structure containing a nickel-phosphorus alloy phase diffused inside.

In the copper-based sintered alloy oil-impregnated bearing of the present invention, the matrix phase containing the copper-nickel-tin alloy has at least a micro Vickers hardness (HMV) (hereinafter referred to as hardness) 170, and the nickel-phosphorus alloy phase is , At least have a hardness of 600.

In the copper-based sintered alloy oil-impregnated bearing of the present invention, the lubricating oil preferably contains 1.5 to 2.5% by mass, and such a lubricating oil is preferably the copper-based sintered alloy oil-impregnated bearing. It is impregnated and held in pores and graphite.

According to the copper-based sintered alloy oil-impregnated bearing of the present invention, the nickel-phosphorus alloy phase that is finely diffused and solidified (crystallized) in the matrix phase containing the copper-nickel-tin alloy is a soft copper-nickel-nickel. It can support a higher load than the matrix phase containing a tin alloy, improves the slidability with the mating material that rubs, and is a metal with the mating material when sliding with a high load applied by the graphite powder and lubricating oil. Contact can be reduced and wear resistance and seizure resistance can be improved.

The method for manufacturing a copper-based sintered alloy oil-impregnated bearing of the present invention is to add copper as a main component from raw materials of copper alone, copper-nickel alloy, nickel alone, tin alone, copper-tin alloy and copper-phosphorus alloy. A copper-based raw material containing 10 to 40% by mass of nickel, 4 to 10% by mass of tin and 0.5 to 5% by mass of phosphorus was prepared, and the copper-based raw material was dissolved to prepare a molten copper-based raw material. Water containing 10 to 40% by mass of nickel, 4 to 10% by mass of tin and 0.5 to 5% by mass of phosphorus in addition to copper as a main component by powdering the molten metal by a water atomization method. A step of preparing an atomized copper-based alloy powder, a step of preparing a graphite powder, and 90 to 97% by mass of water atomized copper-based alloy powder and 3 to 10% by mass of the graphite powder are weighed and put into a mixer and stirred. The process of mixing to prepare a mixed powder of water atomized copper-based alloy powder and graphite powder, and the mixed powder is filled in a desired mold and compression-molded at a molding pressure of 3 to 7 tons / cm ^2. In the process of producing powder, this powder is sintered in a heating furnace adjusted to a reducing atmosphere at a temperature of 800 to 900 ° C. for 10 to 30 minutes, and in addition to copper as the main component, 9 to 9 to A copper-based sintered alloy containing 38.8% by mass of nickel, 3.6 to 9.7% by mass of tin, 0.45 to 4.9% by mass of phosphorus, and 3 to 10% by mass of graphite in a dispersed manner. After the process of manufacturing the body and machining the copper-based sintered alloy body to prepare the desired copper-based sintered alloy bearing, the pores and graphite of the copper-based sintered alloy bearing are 1.5 to 2. It comprises a step of impregnating and holding 5% by mass of lubricating oil.

In the method for producing a copper-based sintered alloy oil-impregnated bearing of the present invention, the water-atomized copper-based alloy powder is made from raw materials for copper alone, copper-nickel alloy, nickel alone, tin alone, copper-tin alloy and copper-phosphorus alloy. In addition to copper as a main component prepared by appropriately selecting, a molten copper-based raw material containing 10 to 40% by mass of nickel, 4 to 10% by mass of tin and 0.5 to 5% by mass of phosphorus is added. By colliding with the fluid (water) injected at high speed, the molten metal is pulverized and cooled. This water atomized copper-based alloy powder instantaneously drops and cools the uniformly melted molten copper-based raw material, so that it has a uniform microstructure without segregation. The water atomized copper-based alloy powder using water as a fluid has an irregular shape.

In the water-atomized copper-based alloy powder thus prepared, nickel forms a solid solution with copper and tin, which are the main components, to form a matrix phase containing a copper-nickel-tin alloy, and phosphorus and a nickel-phosphory alloy. A liquid phase with and is formed to crystallize a nickel-phosphorus alloy phase finely diffused in the matrix phase. If the nickel content is less than 10% by mass, the strength of the matrix phase containing the copper-nickel-tin alloy cannot be obtained, which may reduce wear resistance and load resistance, and the content may be 40% by mass. If it exceeds, the sinterability is lowered, and the strength and abrasion resistance may be lowered. Therefore, the nickel content in the water atomized copper-based alloy powder is preferably 10 to 40% by mass, especially 20 to 35% by mass.

Tin forms a solid solution with copper and nickel, which are the main components, and alloys them to form a matrix phase containing a copper-nickel-tin alloy to strengthen the matrix phase containing a copper-nickel-tin alloy and has abrasion resistance. To improve. If the tin content is less than 4% by mass, the above effect is not sufficiently exhibited, and if the tin content exceeds 10% by mass, the sinterability is lowered and the wear resistance may be lowered. Therefore, the tin content in the water atomized copper-based alloy powder is preferably 4 to 10% by mass, particularly 5 to 8% by mass.

Phosphorus forms a nickel-nickel-phosphorus alloy to crystallize the nickel-phosphorus alloy phase finely diffused in the matrix phase, improving the wear resistance of the matrix phase. When the phosphorus content is less than 0.5% by mass, the ratio of forming a liquid phase of the nickel-phosphorus alloy is small, the effect of improving the abrasion resistance is not sufficiently exhibited, and when the content exceeds 5% by mass. The crystallization ratio of the nickel-phosphorus alloy phase finely diffused in the matrix phase becomes too large, and there is a risk that the wear resistance is deteriorated. Therefore, the phosphorus content in the water atomized copper-based alloy powder is preferably 0.5 to 5% by mass, especially 1 to 3% by mass.

Graphite blended in water atomized copper-based alloy powder enhances self-lubricating property by solid lubrication action, and further improves wear resistance, load resistance and seizure resistance when sliding under high load. It serves as a retainer for lubricating oil. If the graphite content is less than 3% by mass, the above effect is not sufficiently exhibited, and if the content exceeds 10% by mass, the solid lubrication action is enhanced, but the sinterability is deteriorated and the copper-based sintered alloy bearing is deteriorated. May reduce the strength of the Therefore, the graphite content is preferably 3 to 10% by mass, especially 3 to 8% by mass. As the graphite, either natural graphite or artificial graphite can be used, and natural graphite having excellent lubricity is particularly preferably used.

The copper-based sintered alloy body is machined (sizing) so that the dimensions of the copper-based sintered alloy body are within a predetermined tolerance.

The copper-based sintered alloy body thus produced is subjected to an oil-impregnated treatment, and the pores and graphite of the copper-based sintered alloy body are impregnated with 1.5 to 2.5% by mass of lubricating oil and held. It is formed on a copper-based sintered alloy oil-impregnated bearing.

According to the method for manufacturing a copper-based sintered alloy oil-impregnated bearing of the present invention, water atomized copper-based alloy powder from raw materials of copper alone, copper-nickel alloy, nickel alone, tin alone, copper-tin alloy and copper-phosphorus alloy. By producing the above, segregation of metal components that tends to occur when a plurality of single metal powders are mixed can be suppressed, so that a homogeneous copper-based sintered alloy can be obtained. The particles of the water atomizing copper-based alloy powder obtained by the water atomizing method are a matrix phase containing a copper-nickel-tin alloy and a nickel-phosphorus alloy that is finely diffused and solidified (crystallized) in the matrix phase. The nickel-phosphorus alloy phase has a higher hardness than the matrix phase as well as exhibiting a metal structure containing a phase, and even in a copper-based sintered alloy bearing obtained by using this water-atomized copper-based alloy powder. Since it exhibits a metal structure containing the matrix phase and the nickel-phosphorus alloy phase, the nickel-phosphorus alloy phase finely diffused and solidified in the matrix phase is more than the matrix phase containing the copper-nickel-tin alloy. It can support a high load and improve the slidability with the mating material that rubs.

According to the present invention, a nickel-phosphorus alloy phase capable of supporting a higher load than a matrix phase containing a copper-nickel-tin alloy can improve the slidability with a contacting mating material and water atomized copper. The lubricating oil impregnated and held in the base alloy powder and the graphite powder reduces metal contact with the mating material when sliding under high load, and can improve wear resistance and seizure resistance. A bonded metal oil-impregnated bearing can be provided.

FIG. 1 is a microscopic photograph of a water atomized copper-based alloy powder. FIG. 2 is an explanatory view of the metal structure of a copper-based sintered alloy bearing by a micrograph. FIG. 3 is an explanatory view of a metal structure in which a main part of the micrograph of FIG. FIG. 4 is a perspective explanatory view for explaining a thrust test method. FIG. 5 is a perspective explanatory view for explaining a radial swing test method.

Next, the present invention and embodiments thereof will be described in more detail based on the preferred examples shown in the figure. The present invention is not limited to these examples.

<Preparation of water atomized copper-based alloy powder>
Water atomized copper-based alloy powder containing 10 to 40% by mass of nickel, 4 to 10% by mass of tin, 0.5 to 5% by mass of phosphorus and copper as a main component is a raw material metal such as copper alone or copper-. 20 to 35% by mass nickel alloy, nickel alone, tin alone, copper-10% by mass tin alloy and copper-8 to 15% by mass phosphorus alloy are prepared, and 10 to 40% by mass of nickel, 4 to 10% from these raw materials. A copper-based alloy raw material was prepared by appropriately selecting so that mass% tin and 0.5 to 5 mass% phosphorus were contained and copper and unavoidable impurities were contained in the balance, and the copper-based alloy raw material was dissolved. It is produced by producing a copper-based molten alloy (molten metal) and colliding this molten metal with a fluid (water) injected at high speed to pulverize and cool it.

This water atomized copper-based alloy powder has an irregular shape. The particle size of the water atomized copper-based alloy powder is approximately 200 to 300 mesh (74 to 46 μm).

As shown in FIG. 1, the water-atomized copper-based alloy powder 1 containing 30% by mass of nickel, 5% by mass of tin, and 3% by mass of phosphorus and having the balance of copper and unavoidable impurities is a matrix containing a copper-nickel-tin alloy. The matrix phase 2 contains a phase (part that looks white) 2 and a nickel-phosphorus alloy phase (part that looks black) 3 that is finely diffused and solidified (crystallized) in the matrix phase 2, and the matrix phase 2 has a hardness of at least 170. The nickel-phosphorus alloy phase 3 has a hardness of at least 600, respectively.

<Preparation of green compact>
As the graphite powder, a graphite powder selected from natural graphite (scaly graphite, massive graphite, earthy graphite, etc.) and artificial graphite is prepared, and the graphite powder is 3 to 10% by mass, and the water atomized copper-based alloy powder is used. The mixture is blended at a ratio of 90 to 97% by mass, and the graphite powder and the water atomized copper-based alloy powder of this blending ratio are put into a mixer (V-type mixer, rocking mixer, tumbler mixer, etc.) and mixed by stirring, and the water atomized copper is mixed. A mixed powder of a base alloy powder and a graphite powder is prepared. Then, a desired mold, for example, a mold having a rectangular hollow portion or an annular hollow portion is prepared, and this mixed powder is filled in the hollow portion of the mold to form a molding pressure of 3 to 7 tons / cm ² . To prepare a desired green compact by compression molding with.

<Manufacturing of copper-based sintered alloy>
Green compact vacuum or hydrogen gas, a hydrogen-nitrogen mixed gas _{(25vol% H 2 -75vol% N} 2), ammonia decomposition gas (AX _gas: mixed gas of _{75vol% H 2, 25vol% N} 2) reduction of such It is carried into a heating (sintering) furnace adjusted to a sexual atmosphere, heated and sintered at a temperature of 800 to 900 ° C. for 10 to 30 minutes in the heating furnace, and by this heating and sintering, nickel 9 to 38.8 Copper-based firing containing 3.6 to 9.7% by mass of tin, 0.45 to 4.9% by mass of phosphorus, the balance containing copper and unavoidable impurities, and 3 to 10% by mass of graphite. A bonded metal body is produced.

As an example, graphite powder is mixed in a ratio of 3% by mass with respect to 97% by mass of water atomized copper-based alloy powder containing 30% by mass of metal, 5% by mass of tin, and 3% by mass of phosphorus, and the balance is composed of copper and unavoidable impurities. Then, 29.1% by mass of nickel, 4.9% by mass of tin, 2.9% by mass of phosphorus, residual copper and unavoidable impurities prepared by heating and sintering the green compact of the mixed powder obtained by stirring and mixing were added. The copper-based sintered alloy body shown in FIG. 2, which contains and disperses graphite in a proportion of 3% by mass, has a metal structure 4, and the metal structure 4 is a matrix phase 5 containing a copper-nickel-tin alloy. In FIG. 2, reference numeral 6 indicates a hole, and reference numeral 7 indicates graphite. Further, in FIG. 3, the part 5 (the part that looks white) is a matrix phase containing a copper-nickel-tin alloy, and the part 8 (the part that looks black) is finely diffused and solidified (crystallized) in the matrix phase 5. Nickel-phosphorus alloy phase.

The metal structure 4 of the copper-based sintered alloy body in FIGS. 2 and 3 includes a matrix phase containing a copper-nickel-tin alloy, which is a metal structure similar to the metal structure of the particles of the water-atomized copper-based alloy powder. The matrix phase contains a nickel-phosphorus alloy phase that is finely diffused and solidified (crystallized), and the matrix phase 5 has at least a hardness of 170 and is finely diffused into the matrix phase 5. The crystallized nickel-phosphorus alloy phase 8 has a hardness of at least 600.

<Manufacturing of copper-based sintered alloy oil-impregnated bearings>
The copper-based sintered alloy is provided under a pressure condition of approximately 1 to 4 tons / cm ^{2 in} order to bring the dimensions of the copper-based sintered alloy within a predetermined tolerance for the purpose of improving dimensional accuracy and increasing density. Machined (sizing) to produce copper-based sintered alloy bearings that fall within the specified dimensional tolerances. Then, the copper-based sintered alloy bearing is immersed in a container filled with lubricating oil such as spindle oil, motor oil, or gear oil, and the temperature of 100 to 110 ° C. is gradually heated to about 30 to 60 in the container. After holding for a minute, the copper group was cooled to room temperature and then taken out, which was oil-impregnated to impregnate the pores and graphite parts of the copper-based sintered alloy bearing with lubricating oil at a ratio of 1.5 to 2.5% by mass. A sintered alloy oil-impregnated bearing is manufactured.

By preparing a copper-based alloy powder having an irregular shape produced from the raw metal of copper alone, copper-nickel alloy, nickel alone, tin alone, copper-tin alloy and copper-phosphorus alloy by the water atomization method in this way, Since segregation of metal components that are likely to occur when a plurality of metal single powders are mixed can be suppressed, a homogeneous copper-based sintered alloy body and copper-based sintered alloy bearing can be obtained, and also obtained by a water atomization method. The copper-based alloy powder particles exhibit a metal structure containing a matrix phase containing a copper-nickel-tin alloy and a nickel-phosphorus alloy phase that is finely diffused and solidified (crystallized) in the matrix phase. , The nickel-phosphorus alloy phase has a higher hardness than the matrix phase, and the matrix phase and nickel-phosphorus also in the copper-based sintered alloy body and the copper-based sintered alloy bearing obtained by using this water atomizing powder. Since it exhibits a metallic structure containing an alloy phase, the nickel-phosphorus alloy phase finely diffused and solidified in the matrix phase can support a higher load than the matrix phase containing a copper-nickel-tin alloy and rubs. The slidability with the mating material is improved, and the lubricating oil impregnated and held in the pores and graphite parts of the copper-based sintered alloy bearing reduces metal contact with the mating material when sliding under high load. , Abrasion resistance and seizure resistance can be improved.

Hereinafter, the present invention will be described in more detail based on Examples, but the present invention is not limited to these Examples.

Examples 1-14
<Preparation of water atomized copper-based alloy powder>
As metal raw materials, copper alone, copper-25% by mass nickel alloy, copper-30% by mass nickel alloy, copper-35% by mass nickel alloy, nickel alone, tin alone, copper-10% by mass tin alloy and copper-15% by mass A phosphorus alloy was prepared, and a raw material metal was selected to prepare a copper-based alloy raw material. The components of the copper-based alloy raw materials of Examples 1 to 14 are shown in Tables 1 and 2.

This copper-based alloy raw material is melted to produce a copper-based molten alloy (molten metal), and the molten metal is collided with water jetted at high speed to be pulverized and cooled to exhibit an irregular shape. A 300 mesh (74-46 μm) water-atomized copper-based alloy powder was prepared. The water-atomized copper-based alloy powder exhibited a metal structure containing a matrix phase containing a copper-nickel-tin alloy and a nickel-phosphorus alloy phase that was finely diffused and crystallized (solidified) in the matrix phase. Tables 3 and 4 show the component compositions of the water-atomized copper-based alloy powders of Examples 1 to 14 and the micro Vickers hardness (HMV) of the matrix phase containing the copper-nickel-tin alloy and the nickel-phosphorus alloy phase.

<Preparation of green compact>
Natural graphite (scaly graphite) powder is prepared as the graphite powder, the graphite powder is mixed with the water atomized copper-based alloy powder, charged into a mixer (V-type mixer), stirred and mixed, and the water atomized copper base is mixed. A mixed powder of alloy powder and graphite powder was prepared. The composition of the water atomized copper-based alloy powder of Examples 1 to 14 and the mixed powder of graphite is shown in Tables 5 and 6. Then, (1) a mold having a rectangular hollow portion and (2) a mold having an annular hollow portion are prepared, and this mixed powder is filled in the hollow portion of the mold to be 5 tons / cm ² . Compression molding was performed at the forming pressure to prepare (1) a square green compact and (2) an annular green compact.

<Manufacturing of copper-based sintered alloy oil-impregnated bearings>
The green compact was conveyed to the heating (sintering) furnace was adjusted to a reducing atmosphere of hydrogen-nitrogen mixed gas _{(25vol% H 2 -75vol% N} 2), and sintered for 15 minutes sintered at a temperature of 840 ° C. After producing a copper-based sintered alloy body, it is sizing processed to (1) a copper-based sintered alloy thrust bearing having a side of 30 mm and a thickness of 5 mm, and (2) an inner diameter of 20 mm, an outer diameter of 28 mm, and a height of 15 mm. A copper-based sintered alloy radial bearing having dimensions was manufactured. It was confirmed that these copper-based sintered alloy bearings exhibit a metal structure having a matrix phase containing a copper-nickel-tin alloy and a nickel-phosphorus alloy phase finely diffused and crystallized in the matrix phase. did. Then, the micro Vickers hardness of the matrix phase containing the copper-nickel-tin alloy and the nickel-phosphorus alloy phase was measured.

Then, the copper-based sintered alloy bearing is immersed in a container filled with lubricating oil, and oil-impregnated treatment is performed to keep the inside of the container for 30 minutes while gradually heating to a temperature of 100 ° C. to lubricate the pores and graphite parts. A copper-based sintered alloy oil-impregnated bearing impregnated with oil was produced. Tables 7 and 8 show the components of the copper-based sintered alloy oil-impregnated bearing, the micro Vickers hardness and the oil content of the matrix phase containing the copper-nickel-tin alloy and the nickel-phosphorus alloy phase.

Comparative Example 1
Atomized copper-10% by mass tin alloy powder passing through a sieve having a particle size of 350 mesh (45 μm) 80% by mass, natural graphite (scaly graphite) powder passing through a sieve having a particle size of 100 mesh (150 μm) 5% by weight And 15% by mass of electrolytic copper powder passing through a sieve having a particle size of 350 mesh (45 μm) was put into a V-type mixer and mixed for 20 minutes to obtain a mixed powder. This mixed powder was filled in a square hollow portion of a mold similar to the above embodiment and compression molded at a molding pressure of 2 tons / cm ² to prepare a square green compact. The green compact heating which is adjusted to a reducing atmosphere of hydrogen-nitrogen mixed gas _{(25vol% H 2 -75vol% N} 2) and conveyed to (sintering) furnace, and sintered for 60 minutes sintered at a temperature of 760 ° C. Copper After producing the base sintered alloy body, it is sizing processed to (1) copper-based sintered alloy thrust bearing with a side of 30 mm and a thickness of 5 mm, and (2) an inner diameter of 20 mm, an outer diameter of 28 mm, and a height of 15 mm. Copper-based sintered alloy radial bearings (copper: 87% by mass, tin: 8% by mass, graphite 5% by mass) were produced. Then, the copper-based sintered alloy bearing was subjected to the same oil-impregnating treatment as in the above embodiment to produce a copper-based sintered alloy oil-impregnated bearing.

Comparative Example 2
Atomized copper-25% by mass nickel alloy powder passing through a sieve with a particle size of 100 mesh (150 μm) 87% by mass, atomized tin powder passing through a sieve with a particle size of 250 mesh (63 μm) 8% by mass, particle size 150 5% by mass of natural graphite (scaly graphite) powder passing through a mesh (106 μm) sieve was put into a V-type mixer and mixed for 20 minutes to obtain a mixed powder. This mixed powder was filled in a square hollow portion of a mold similar to the above embodiment and compression molded at a molding pressure of 2 tons / cm ² to prepare a square green compact. The green compact heating which is adjusted to a reducing atmosphere of hydrogen-nitrogen mixed gas _{(25vol% H 2 -75vol% N} 2) and conveyed to (sintering) furnace, and sintered for 30 minutes sintered at a temperature of 920 ° C. Copper After producing the base sintered alloy body, it is sizing processed to (1) copper-based sintered alloy thrust bearing with a side of 30 mm and a thickness of 5 mm, and (2) an inner diameter of 20 mm, an outer diameter of 28 mm, and a height of 15 mm. Copper-based sintered alloy radial bearings (copper: 65.2% by mass, nickel: 21.8, tin: 8% by mass, graphite 5% by mass) were produced. Then, the copper-based sintered alloy bearing was subjected to the same oil-impregnating treatment as in the above embodiment to produce a copper-based sintered alloy oil-impregnated bearing.

Comparative Example 3
Atomized copper-30% by mass nickel alloy powder passing through a sieve with a particle size of 100 mesh (150 μm) 89% by mass, atomized tin powder passing through a sieve with a particle size of 250 mesh (63 μm) 8% by mass, particle size 150 3% by mass of natural graphite (scaly graphite) powder passing through a mesh (106 μm) sieve was put into a V-type mixer and mixed for 20 minutes to obtain a mixed powder. Hereinafter, in the same manner as in Comparative Example 2, (1) a copper-based sintered alloy thrust bearing having a side of 30 mm and a thickness of 5 mm, and (2) a copper-based firing having an inner diameter of 20 mm, an outer diameter of 28 mm, and a height of 15 mm. A bonded gold radial bearing (copper: 62.3% by mass, nickel: 26.7, tin: 8% by mass, graphite 3% by mass) was produced. Then, the copper-based sintered alloy bearing was subjected to the same oil-impregnating treatment as in the above embodiment to produce a copper-based sintered alloy oil-impregnated bearing.

Comparative Example 4
Atomized copper-35% by mass nickel alloy powder 65.7% by mass passing through a sieve having a particle size of 100 mesh (150 μm), 5% by mass of atomized tin powder passing through a sieve having a particle size of 250 mesh (63 μm), particle size Is 2.7% by mass of copper-15% by mass P alloy powder passing through a 200 mesh (75 μm) sieve, 21.6% by mass of electrolytic copper powder passing through a 350 mesh (45 μm) sieve, and has a particle size of 21.6% by mass. 5% by mass of natural graphite (scaly graphite) powder passing through a 150 mesh (106 μm) sieve was put into a V-type mixer and mixed for 20 minutes to obtain a mixed powder. Hereinafter, in the same manner as in Comparative Example 2, (1) a copper-based sintered alloy thrust bearing having a side of 30 mm and a thickness of 5 mm, and (2) a copper-based firing having an inner diameter of 20 mm, an outer diameter of 28 mm, and a height of 15 mm. A bonded gold radial bearing (copper: 66.6% by mass, nickel: 23% by mass, tin: 5% by mass, phosphorus: 0.4% by mass, graphite 3% by mass) was produced. Then, the copper-based sintered alloy bearing was subjected to the same oil-impregnating treatment as in the above embodiment to produce a copper-based sintered alloy oil-impregnated bearing.

Table 8 shows the components and oil content of the copper-based sintered alloy oil-impregnated bearings of Comparative Examples 1 to 4.

Next, in the copper-based sintered alloy oil-impregnated bearings obtained in Examples 1 to 14 and Comparative Examples 1 to 4, the copper-based sintered alloy oil-impregnated thrust bearings are thrust-sliding according to the thrust test conditions shown below. The dynamic characteristics were evaluated, and for the copper-based sintered alloy oil-impregnated radial bearing, the journal swinging sliding characteristics were evaluated under the journal swinging test conditions shown below. The coefficient of friction indicates the coefficient of friction at the time of stability 1 hour after the start of the test, and the amount of wear indicates the amount of dimensional change of the sliding surface of the copper-based sintered alloy oil-impregnated bearing after the end of the test time ( It is shown by μm).

<Thrust test conditions>
Speed 1.3m / min
Load (surface ^{pressure) (1) 300kgf / cm 2} (2) 500kgf / cm 2
Test time 20 hours Mating material Carbon steel for machine structure (S45C)
Lithium grease ("Daphney Eponex (trade name)" manufactured by Idemitsu Kosan Co., Ltd.) is applied to the sliding surface at the start of the lubrication test.

<Test method>
As shown in FIG. 4, the copper-based sintered alloy oil-impregnated thrust bearing 9 as the copper-based sintered alloy oil-impregnated bearing is fixed, and the cylindrical body 10 as the mating material is mounted on the copper-based sintered alloy oil-impregnated thrust bearing 9 ( (A direction of arrow A) While applying a predetermined load to the surface 11, the cylindrical body 10 is rotated in the direction of arrow B, and the friction coefficient between the copper-based sintered alloy oil-impregnated thrust bearing 9 and the cylindrical body 10 and the elapse of the test time. The amount of wear of the later copper-based sintered alloy oil-impregnated thrust bearing 9 was measured.

<Journal swing test conditions>
Speed 0.5m / min
Load (surface pressure) 300 kgf / cm ²
Swing angle ± 45 °
Test time 100 hours Mating material Bearing steel (SUJ2 hardened material)
Lubrication conditions Lithium grease (same as above) is applied to the sliding surface at the start of the test.

<Test method>
As shown in FIG. 5, a load in the direction of arrow A is applied to and fixed to the copper-based sintered alloy oil-impregnated radial bearing 12 as the copper-based sintered alloy oil-impregnated bearing, and the rotating shaft 13 serving as the mating material has a constant sliding speed. The amount of wear of the copper-based sintered alloy oil-impregnated radial bearing 12 after the lapse of the test time was measured by swinging and rotating in the direction of arrow C.

Tables 7 and 8 show the thrust test results and the radial swing test results of the copper-based sintered alloy oil-impregnated thrust bearing 9 and the copper-based sintered alloy oil-impregnated radial bearing 12.

表８中、比較例１の面圧（２）の条件におけるスラスト試験結果の＊印は、試験開始直後に摩擦係数が急激に上昇したため試験を中止し、摩擦係数及び摩耗量の測定ができなかったことを示す。

In Table 8, the * mark in the thrust test result under the condition of the surface pressure (2) of Comparative Example 1 indicates that the test was stopped because the friction coefficient increased sharply immediately after the start of the test, and the friction coefficient and the amount of wear could not be measured. Show that.

From the results of the thrust test and the radial rocking test, it can be seen that the copper-based sintered alloy oil-impregnated bearing of the example has a lower friction coefficient and a smaller amount of wear than the copper-based sintered alloy oil-impregnated bearing of the comparative example. In particular, the copper-based sintered alloy oil-impregnated bearing of the embodiment has a metal structure containing a matrix phase containing a copper-nickel-tin alloy and a nickel-phosphorus alloy phase finely diffused and crystallized in the matrix phase. However, the nickel-phosphorus alloy phase, which is finely diffused and solidified in the matrix phase, can support a higher load than the matrix phase and rubs against each other due to the overlapping effect of the solid lubricating action of graphite and the lubricating action of the lubricating oil. It is presumed that the wear resistance is improved by improving the slidability with the material.

As described above, the copper-based sintered alloy oil-impregnated bearing according to the present invention comprises a matrix phase containing a copper-nickel-tin alloy and a nickel-phosphorus alloy phase finely diffused and crystallized in the matrix phase. It has a metallic structure containing metal, and the nickel-phosphorus alloy phase supports a high load to improve the slidability with the mating material that rubs against it, and the solid graphite that is dispersed and contained in the copper-based sintered alloy oil-impregnated bearing. Due to the lubricating action and the overlapping effect with the lubricating action of the lubricating oil impregnated and held in the pores and graphite parts, metal contact with the mating material is reduced during sliding when a high load is applied, and wear resistance and seizure resistance Can be improved. Further, in the production method according to the present invention, a copper-based alloy powder is produced from the raw metal of copper alone, copper-nickel alloy, nickel alone, tin alone, copper-tin alloy and copper-phosphorus alloy by the water atomization method. As a result, segregation of metal components that tends to occur when a plurality of single metal powders are mixed can be suppressed, so that a homogeneous copper-based sintered alloy oil-impregnated bearing can be obtained.

1 Water atomized copper-based alloy powder 2, 5 Matrix phase 3, 8 Nickel-phosphorus alloy phase 4 Metal structure 6 Pore 7 Graphite

Claims (2)

It contains nickel, tin and phosphorus, a water-atomized copper-based alloy powder containing copper as a main component, graphite powder, and lubricating oil. Nickel 19.4 to 38.8% by mass, tin 3.6 to 9 A matrix phase containing 7.7% by mass, 0.45 to 4.9% by mass of phosphorus and 3 to 10% by mass of graphite, and containing a copper-nickel-tin alloy, and a nickel-phosphory alloy phase diffused in the matrix phase. It has a inclusive metal structure,
Copper - Nickel - matrix phase comprising a tin alloy has at least a micro Vickers hardness 175, nickel - phosphorus alloy phase, copper-based sintered alloy oil-impregnated bearings that have at least micro Vickers hardness 613. The copper-based sintered alloy oil-impregnated bearing according to claim 1, wherein the lubricating oil contains 1.5 to 2.5% by mass.

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