JP2539246B2 - Sintered alloy bearing material and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION “Object of the Invention” The present invention relates to a sintered alloy bearing material and a method for manufacturing the same, and it is as excellent in corrosion resistance as a copper-based material under bearing conditions while ensuring appropriate strength, and a shaft. An object of the present invention is to provide a sintered alloy material having good compatibility with a mating member such as a material and a small friction coefficient, and having excellent performance as a bearing material, and a method for producing the same.

(Industrial field of application) Sintered oil-impregnated bearings and other sintered alloy bearing materials and their manufacturing technology.

(Conventional technology) For sintered oil-impregnated bearings, JIS B 15
As specified in 81-1976, bearing materials such as cylindrical, flanged cylindrical and spherical used for household electrical equipment, audio equipment, office machinery, agricultural machinery, automobiles and other transporting and handling equipment, etc. It is variously defined, and its main component composition is pure iron, iron-copper, iron-carbon, iron-copper-carbon, iron-copper-lead, bronze, copper, lead-bronze. The materials and types are relatively diverse.

Note that, for example, in Japanese Patent Laid-Open No. 56-51554, it is announced that a green compact made of iron powder and brass powder is sintered, and the present inventors further disclose in Japanese Patent Laid-Open No. 60-200927. It has been proposed to use iron powder, brass powder, and nickel-white powder to sinter a powder compact formed by mixing these powders in a reducing atmosphere.

(Problems to be Solved by the Invention) The oil-impregnated bearing mainly composed of iron described above is excellent in skeletal strength and is preferable for high loads, but it is inferior in conformability to a counterpart member and corrosion resistance, and thus is restricted in use. .

On the other hand, a material mainly composed of copper or bronze has good adaptability and corrosion resistance, but is not suitable for high loads because of insufficient strength.

Iron-copper alloys (including iron-copper-lead, iron-copper-carbon, etc.) have intermediate properties between them, but are still insufficient in strength and corrosion resistance.

In the case of using the iron powder and the brass powder according to the above-mentioned JP-A-56-51554, although the corrosion resistance is preferable, the strength and the conformability to the mating member are not sufficient.

Japanese Patent Application Laid-Open No. Sho 60-200927 aims at achieving sufficient corrosion resistance and reducing the friction coefficient while securing strength by using nickel silver, but it does not always satisfy those characteristics. In addition, it is insufficient in conformity to a mating member such as a shaft.

Further, in the conventional one as described above, it is indispensable to use a considerable amount of iron powder in order to obtain an appropriate strength and to obtain a product at a relatively low cost. Is not completely covered even if it is buried in the copper powder or brass powder, for example, as shown in FIG. 5 for the example in which 30% of the copper powder is mixed, the iron powder 1 and the copper powder 2 are substantially the same. Inevitably, the iron powder particles 1 exposed in accordance with the mixing ratio of No. 1 and No. 2 are exposed, and thus the iron powder particles 1 are brought into contact with the mating member to wear it and become a base point of corrosion generation.

"Structure of the invention" (Means for solving the problem) 1. Fe: 20 to 64 wt%, Cu: 32.8 to 77 wt%, Sn: 1 to 9 wt% and P: 0.02 to 0.9 wt% In addition, the Fe is in the form of powder, and the peripheral surface of the powdery Fe is substantially completely plated with Cu corresponding to 20 to 50 wt% of the Fe, and the porosity is set to 15 to 28 vol%. And sintered alloy bearing material.

2.Fe: 20-64wt%, Cu: 28.6-76.5wt%, Sn: 0.75-8.9
In addition to containing wt%, P: 0.015 to 0.9 wt% and 1 of solid lubricants such as graphite, molybdenum disulfide and lead.
0.5 to 5 wt% of one kind or two or more kinds, and the Fe is in the form of powder, and the peripheral surface of the powdered Fe is plated and coated in a substantially complete state with Cu corresponding to 20 to 50 wt% thereof, and has pores. Sintered alloy bearing material characterized by a rate of 15 to 28 vol%.

3. For 100 parts by weight of iron powder coated with 20 to 50% by weight of copper, Sn: 5 to 15% by weight, P: 0.1 to 1.5% by weight and the balance Cu
Sintered alloy bearings characterized in that 25 to 150 parts by weight of phosphor bronze powder consisting of unavoidable impurities are added and mixed into a raw material powder, which is compacted, sintered, and then sized to a porosity of 15 to 28 vol%. Method of manufacturing timber.

4. For 100 parts by weight of iron powder coated with 20 to 50 wt% copper, Sn: 5 to 15 wt%, P: 0.1 to 1.5 wt% and the balance Cu
And 18 to 147 parts by weight of phosphor bronze powder consisting of unavoidable impurities and 0.5 to 5.3 parts by weight of one or more solid lubricants such as graphite, molybdenum disulfide or lead are added and mixed into the raw material powder. Powder forming and sintering, then porosity 15 ~
A method for manufacturing a sintered alloy bearing material, which comprises sizing to 28 vol%.

5. Any of the above-mentioned item 3 or item 4 in which the green compact obtained by green compacting the raw material powder is housed in a heat-resistant container, covered and sintered in a reducing atmosphere at 750 to 950 ° C. A method for manufacturing a sintered alloy bearing material according to one of the claims.

(Function) Contains Fe: 20 to 64 wt%, Cu: 32.8 to 77 wt%, Sn: 1 to 9 wt% and P: 0.02 to 0.9 wt% to ensure strength and compatibility with the mating member. Maintain
Moreover, it exhibits excellent properties in corrosion resistance. That is, by adding an appropriate amount of P as described above, the reducing and cleaning action of the oxide can be obtained, the strength and the corrosion resistance are appropriately improved, and the conformability to the counterpart member is remarkably improved.

The powder particles of Fe in the sintered alloy are 20 to 50 wt% Cu
By being coated in a substantially complete state by
Fe powder particles are not exposed on the surface of the product, that is, the product surface is effectively and densely coated with Cu, and corrosion resistance is greatly improved, and compatibility with the counterpart member and thermal conductivity are also improved. Be punished. As for the sintering between powder particles, a stable sintering relationship is formed because there is no intervention of Fe particles.

When Fe is 20 wt% or less, sufficient strength cannot be obtained, and a large amount of other components is required, resulting in high cost. On the other hand, exceeding 60 wt% Fe
Those containing the alloy have a high friction coefficient, the compatibility with the counterpart member cannot be ensured, and the corrosion resistance rapidly deteriorates.

When the Cu content is 32.8 wt% or more, the conformability is secured, and when the upper limit is 77 wt%, the low cost property is obtained and the Fe content is at least 20 wt% or more to obtain the strength.

By setting Sn to be 1 wt% or more, strength and corrosion resistance are secured in combination with Cu and P, and by setting the upper limit to 9 wt%, the conformability is appropriately maintained.

When P is 0.02 wt% or more, the reducing and cleaning action on the oxide is appropriately obtained, and the strength and the corrosion resistance are effectively enhanced. On the other hand, if the upper limit is 0.9 wt%, strength and conformability are maintained, and an increase in friction coefficient is suppressed.

By compacting and sintering, and then sizing to a porosity of 15 vol% or more, the oil content in the case of bearing materials can be properly obtained and the lubrication performance can be improved. On the other hand, the porosity is 28vo
The strength is secured by not exceeding l% and the impregnated oil is prevented from flowing out and scattering.

Lubricity is increased and the coefficient of friction is reduced by containing 0.5 wt% or more of one or more solid lubricants such as graphite, molybdenum disulfide or lead. The strength of the product is maintained by not exceeding 5.0 wt%.

By using a phosphor bronze powder containing Sn: 5 to 15 wt% and P: 0.1 to 1.5 wt% with the balance being Cu and inevitable impurities, C
u, Sn and P are simultaneously added as an alloy body, and the complication of preparing these components separately and sequentially mixing them is avoided.
Further, segregation of the blended components is appropriately prevented, and a uniform sintered structure is easily formed. Further, since such a phosphor bronze powder is a copper-based alloy, it has good compatibility with the copper layer coated with iron particles as described above, and is formed with a stable sintering mechanism.

(Example) A specific embodiment of the present invention as described above will be described. The present invention is basically a sintered alloy containing P in addition to Fe, Cu and Sn, and the Fe is Cu. Fe is coated with Cu although they are coated and these may be prepared separately. As described above, the material may be prepared as an alloy for other components as well, and various powders of phosphorus-tin and phosphorous copper, iron powder and copper powder, and alloys of Fe, Cu, Sn and P are also available. It is possible to use alloy powder of However, preferred materials are pure iron powder coated with Cu and phosphor bronze powder, and in some cases Ni may be contained in an appropriate amount.

Fe is generally 20 to 64 wt%, but preferably 30 to 60
wt%, and more preferably 40 to 55 wt%. Further, Cu is generally 32.8 to 77 wt% as described above, but preferably 35 to 60 wt%, more preferably 38 to 55 wt%. The general range of Sn is 1 to 9 wt%, preferably 3 to 9 wt%, more preferably 4.5 to 9 wt%. The preferred range for P is 0.02 to the above general range.
It is 0.9 wt%, and more preferably 0.06 to 0.72 wt%.

The above-mentioned iron powder is prepared as coated with 20 to 50 wt% of Cu as described above. Such iron powder is coated with copper by a plating method or the like, and the amount of such coating can be adjusted to an appropriate degree by appropriately selecting the amount of electricity and the time during plating. As described above, the coating amount of such copper is 20 to 50% by weight, but a more preferable range is about 25 to 45%.
Due to such copper coating, the peripheral surface of the iron powder particles is completely covered with the copper coating as shown in FIGS.
Further, as shown in FIGS. 1 and 2, the soft powder layer 2a of copper is formed on the surface of the iron powder particle 1 by forming the unevenness 3 on the surface of the iron powder particle 1 so that the powder compaction is still performed. 32.8-77%
The Cu content exceeding 20 to 50% is added as a copper-based powder separately. By separately adding the copper-based powder in this manner, the coating state effective for the iron powder is maintained even after compacting and sintering, and favorable conformability and corrosion resistance are secured.

The size of the iron powder particles as the raw material is not particularly limited, but a particle range that is further expanded than the 100 mesh or less, which is conventionally generally used for producing pure iron-based sintered bodies, is adopted. be able to. In other words, even relatively fine-grained ones can be treated in the same manner as those in the conventional general range in terms of particle size by copper coating and the particle size can be treated in the same manner as in the conventional general range. Even those having a large diameter exceeding the normal particle size range can be formed to the same or more easily by a compacting process similar to the conventional method.

Graphite, molybdenum disulfide, etc. as solid lubricants are naturally added as powders, but solid lubricants such as graphite have a low specific gravity for both copper-coated iron powder and phosphor bronze powder. Therefore, it is difficult to disperse the raw materials in a uniform state with other raw material powders simply by mixing such graphite, and the graphite is not used during the handling of cargo, replacement with the press hopper, compaction molding, etc. Segregation occurs due to the floating of the powder and offset. Therefore, experiments have confirmed that it is effective to use a relatively coarse powder of a solid lubricant such as graphite, and to use a powder obtained by classifying and removing the fine powder. That is, the commercially available graphite powder is generally 1 to 30 μm, or 1 to 30 μm.
Graphite as a solid lubricant preferred by the inventors of the present invention has a particle size of 50 to 50 μm, and is 10 to 150 μm, particularly 20 to 100 μm, and is a coarse powder and a fine powder having a particle size of 10 μm or 20 μm or less. Thereby, uniform dispersion can be facilitated, and occurrence of segregation during cargo handling or other handling can be prevented as much as possible. Less than 10 μm as above, or
Fine particles having a size of less than 20 μm do not generate dust during classification in a liquid, and can be appropriately classified.

In addition, according to the present invention, metal or alloy powder other than the above may be appropriately added if necessary.

The powder compaction is generally performed under a pressure of about ² to 3 TON / cm ² , and its porosity is 22 to 35 vol%. When the content is less than 22 vol%, it is difficult to perform effective sizing and obtain a product having a porosity suitable for oil impregnation and the like. On the other hand, a green compact having a porosity exceeding 35 vol% is highly likely to be damaged or broken during sintering. Sintering is 750-950 ℃, especially
It is carried out in a reducing atmosphere at 750 to 850 ° C, but this sintering temperature is considerably lower than the sintering temperature when iron powder is used,
Simplify the sintering process.

Even if the present invention uses phosphor bronze as a main raw material, it will be deformed to some extent by sintering, and since such distortion and deformation cannot be avoided, it is sized to obtain a product of a required size.

A specific manufacturing example of the device according to the present invention is as follows.

Production Example 1. While preparing a copper-coated iron powder coated with Cu corresponding to 40 wt% of the Fe particle surface, prepare a phosphor bronze powder having a composition of Sn: 10.4% and P: 0.32%. 30 parts of copper-coated iron powder,
A raw material powder was used in which phosphor bronze powder was added and mixed at a ratio of 70 parts, 40 parts and 10 parts to 60 parts and 90 parts. The theoretical wt% of the raw powders of these are as shown in Table 1 below.

Tables 2 to 4 summarize the compacting conditions and sintering conditions of these raw material powders, the sintering conditions, and the characteristic values of the obtained products. Raw material powder, Table 3 is based on raw material powder, and Table 4 is based on raw material powder.

That is, the molding density ratio is 65-75%, and the sintering temperature is 800 ℃ -850 ℃.
However, it was confirmed that the end face hardness and radial crushing strength were significantly increased by setting the sintering temperature to 850 ° C. That is, FIG. 3 summarizes the relationship between effective porosity and radial crushing strength, and FIG. 4 summarizes the relationship between end face hardness and effective porosity. It was confirmed that preferable strength can be ensured even under the condition that the porosity exceeds 30%.

Production Example 2. Iron powder having a particle size of 100 mesh or less coated with 30 wt% Cu and phosphor bronze containing 10 wt% Sn and 0.35 wt% P were prepared, and these powders were prepared as shown in Table 5 below. The raw material powder was mixed in the mixing ratio as shown in.

Each of the above-mentioned raw material powders according to Table 1 was sufficiently mixed and then compacted, that is, molded into an annular bearing body having an outer diameter of 10 mm and an inner diameter of 4 mm with a pressing force of about 2.0 TON / cm ² . .

These green compacts are then transferred to a sintering process, i.e. charged into a sintering furnace with a maximum temperature of 1050 ° C.
Sintering was performed for 45 minutes in a reducing atmosphere of 820 ° C. with AX gas.

Each sintered body thus obtained was then sized to obtain a product having a porosity of 20 vol%. When such a product was examined with a magnifying glass, all of the iron powder particles were covered with a copper layer in a substantially complete state, and the exposed portion was substantially invisible.

The results of examining the composition of each sintered body thus obtained are shown in Table 6 below.

Each product obtained as described above was then subjected to oil immersion treatment, that is, air in pores was removed under a vacuum condition of about -30 mmHg and impregnated with turbine oil to obtain an oil-impregnated bearing.

These products were subjected to characteristic tests. That is, each of the above-mentioned products, and the iron-based sintered bearing and the pure iron powder and the brass powder according to the prior art described above as a comparative material were separately prepared.
Prepared by mixing at a ratio of 0:50, compacting, sintering and sanding to 20 vol% which is the same porosity of each product described above, for these products ~ and comparative materials radial crushing strength, friction Coefficient and PV value 1000kg / cm ²・ m ・
Table 7 below shows the results of measuring the temperature rise value during continuous rotation at a min of 40 minutes (the temperature gradually rises up to about 30 minutes under this condition, but almost no temperature rises thereafter). is there.

Table 8 below shows the results obtained by performing the corrosion resistance test on each of the products according to the present invention and the comparative materials as described above at a humidity of 80% and a temperature of 60 ° C, and measuring the time until the occurrence of rust. It was

That is, in this production example, the copper coverage is 30 wt% and the production example 1
It was confirmed that although the coating amount was smaller, it still had very excellent corrosion resistance.

Production Example 3. A product was produced in the same manner as in Production Example 1 except that 2 wt% of graphite powder was externally added to the proportions shown in Table 5 in Production Example 2 described above.

The friction coefficient of this product is 0.062, and the manufacturing example 2
It has been confirmed that it has better lubrication properties than the above, and its radial crushing strength is 26.5 kg / cm ² , which also satisfies the requirements for such bearing materials in terms of strength. Therefore, it was confirmed that there is a preferable product.

Production Example 4. 20% by weight of the copper coating on the iron powder in Production Example 2
And the same procedure as in Production Example 2 except that the content was changed to 40 wt%.

That is, the copper coating amount is 20 wt%, and this copper coating amount is
The component composition of the product obtained with 40 wt% is as shown in Table 9 below.

That is, in spite of the fact that the respective values differ to some extent as the Cu coating amount changes, the substantial composition of the components is substantially the same as in Production Example 1 especially in the case of containing no volatile components.
It can be said that it is similar to that of.

Table 10 shows the results of the radial crushing strength, the coefficient of friction, the temperature rise value during continuous rotation, and the time during which rusting was observed under the same test conditions as in Production Example 1 were determined for this product. .

That is, it was confirmed that all the above characteristic values should be satisfied even if the copper coating amount relative to the iron powder changes as described above.

[Advantages of the Invention] According to the present invention as described above, while having the same strength as that of the iron-based sintered material, the compatibility with the shaft material is as good as that of the copper-sintered material, and the corrosion resistance, etc. The present invention provides a bearing material which is remarkably excellent and a preferable manufacturing method thereof, and is an invention having a great effect industrially.

[Brief description of drawings]

The drawings show the technical contents of the present invention. FIGS. 1 and 2 are cross-sectional views showing one example of the copper-coated iron powder used in the present invention in a microscopically enlarged manner, and FIG. A chart summarizing the relationship between the radial crushing strength and the effective porosity according to Production Example 1,
FIG. 4 is a table which summarizes the relationship between the surface hardness and the effective porosity in the same manner as in Production Example 1, and FIG. 5 is the surface property of the product according to the ratio of 70 wt% iron powder and 30 wt% copper powder according to the conventional technique. It is explanatory drawing which expanded and showed microscopically. In these drawings, 1 is iron powder particles, 2 is copper powder particles, and 2a is copper powder or copper powder particles coated with copper.

Claims (5)

(57) [Claims] 1. Fe: 20-64 wt%, Cu: 32.8-77 wt%, Sn: 1-
It contains 9 wt% and P: 0.02 to 0.9 wt%, and the Fe is in the form of powder, and the peripheral surface of the powder Fe is made substantially complete by Cu corresponding to 20 to 50 wt%. A sintered alloy bearing material which is plated and has a porosity of 15 to 28 vol%. 2. Fe: 20 to 64 wt%, Cu: 28.6 to 76.5 wt%, Sn:
It contains 0.75 to 8.9 wt% and P: 0.015 to 0.9 wt% and 1 of solid lubricants such as graphite, molybdenum disulfide and lead.
0.5 to 5 wt% of one kind or two or more kinds, and the Fe is in the form of powder, and the peripheral surface of the powdered Fe is plated and coated in a substantially complete state with Cu corresponding to 20 to 50 wt% thereof, and has pores. A sintered alloy bearing material characterized by a rate of 15 to 28 vol%. 3. An iron powder 100 coated with 20 to 50 wt% of copper.
25 parts by weight of phosphor bronze powder containing Sn: 5 to 15 wt%, P: 0.1 to 1.5 wt% and the balance Cu and unavoidable impurities with respect to parts by weight.
A method for producing a sintered alloy bearing material, which comprises compacting and mixing 150 parts by weight of raw material powder mixed and mixed, and then sizing to a porosity of 15 to 28 vol%. 4. An iron powder 100 coated with 20 to 50 wt% of copper.
18 parts by weight of phosphor bronze powder containing Sn: 5-15 wt%, P: 0.1-1.5 wt% and the balance Cu and unavoidable impurities with respect to parts by weight.
147 parts by weight and 0.5 or 5.3 parts by weight of one or more solid lubricants such as graphite, molybdenum disulfide or lead are added and mixed, and the raw material powder is compacted and sintered, and then the porosity is obtained. A method for manufacturing a sintered alloy bearing material, which comprises sizing to 15 to 28 vol%. 5. A powder compact obtained by compacting raw material powder is housed in a heat-resistant container, capped, and sintered in a reducing atmosphere at 750 to 950 ° C. The method for manufacturing a sintered alloy bearing material according to any one of claims.