JPH0819947B2 - Sintered bearing made of Cu alloy having excellent compatibility and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention has excellent conformability, and in particular, dry and oil-impregnated Cu alloy sintered bearings capable of significantly shortening the conforming operation time, And the manufacturing method thereof.

[Conventional technology]

Conventionally, it generally contains Sn: 3 to 20%, Pb: 0.1 to 20%, and if necessary, C: 0.1 to 10%, MoS ₂ : 0.1 to 10%, P: 0.05 to 2%, B: 0.01 to 2%, Zn: 0.01 to 10%, containing 1 or 2 or more of them, and the balance of Cu and unavoidable impurities (above wt%, below% regarding composition components represent wt% Shown), and a dry or oil-impregnated type Cu alloy sintered bearing having a porosity of 5 to 30% is known, and this Cu alloy sintered bearing is often manufactured by an ordinary powder metallurgy method. It is known.

[Problems to be solved by the invention]

However, in the above-mentioned conventional Cu alloy sintered bearing, when it is built in the device and the running-in operation is performed, it takes a relatively long time until it shows a constant friction coefficient. From the standpoint of cost rationalization, it is strongly desired to reduce the familiar operating time.

[Means for solving problems]

Therefore, as a result of conducting research to develop a Cu oil-containing sintered oil-impregnated bearing having excellent compatibility from the above viewpoints, the present inventors have found that the above dry-type or oil-impregnated conventional Cu is used.
Sintered alloy bearings in air. In an inert gas atmosphere, a reducing gas atmosphere, or a vacuum atmosphere (any of these atmospheres may be referred to as an unconditional atmosphere), heat treatment is performed at a predetermined temperature within a range of 180 to 350 ° C while maintaining heat. When applied, Sn and Pb are eluted on the surface to form a Sn-Pb alloy layer.
It was found that the alloy layer is soft and has a very good conformability, and as a result, the familiar operating time of the Cu alloy sintered bearing is extremely short.

The present invention has been made based on the above findings, containing Sn: 3 to 20%, Pb: 0.1 to 20%, and, if necessary, C: 0.1 to 10%, MoS ₂ : 0.1 to 10%, P: 0.05 to 2%, B: 0.01 to 2%, Zn: 0.01 to 10%, and a composition containing at least one of Cu and the balance Cu and inevitable impurities, and Average layer thickness: 0.1-10 μm on the surface of a Cu alloy sintered bearing having a porosity of 5-30%
The soft Sn-Pb alloy layer is formed by elution-forming and has excellent compatibility with a dry or oil-containing Cu alloy sintered bearing, and the elution-forming heat treatment of the Sn-Pb alloy layer described above in an unconditional atmosphere, Cu of dry type or oil-impregnated type with excellent compatibility, which is performed under the condition of heating and holding at a predetermined temperature within the range of 180 to 350 ° C.
It is characterized by a method for manufacturing a sintered alloy bearing.

Next, with respect to the sintered bearing of the present invention, the reasons why the component composition, the porosity, the heat treatment temperature, and the average layer thickness of the Sn—Pb alloy layer are limited as described above will be described.

A. Component composition (a) Sn The Sn component wets well with Cu and Pb and has the effect of improving the strength, but if the content is less than 3%, the desired strength cannot be ensured, while When the content exceeds 20%, the δ phase excessively precipitates and becomes brittle, so the content was defined as 3 to 20%.

(B) Pb The Pb component has the function of improving the lubricity by being dispersed in the matrix, but if its content is less than 0.1%, the desired lubricity cannot be obtained, while its content exceeds 20%. Then, the strength is lowered, so the content is set to 0.1 to 20%.

(C) C and MoS _{2 Since} these components have the effect of improving lubricity, they are contained as necessary, especially when lubricity is required.
Their contents are C: less than 0.1% and MoS ₂ : 0.1%, respectively.
Can not be obtained on the effect desired lubricating牲向is less than, while its content of C: 10% and MoS _2: exceeds 10%, respectively, since the reduction in strength becomes remarkable, the content of C: 0.1 to 10
%, MoS ₂ : 0.1-10%.

(D) P and B These components have the function of improving the strength by performing liquid phase sintering, so they are contained as necessary when high strength is required. P: 0.05
% And B: less than 0.01%, the desired strength improving effect cannot be obtained, while the contents are P: 2% and B: 2%, respectively.
If the content exceeds P, the dimensional change will be significant and the opponent's aggression will increase.
It was set as 05-2% and B: 0.01-2%.

(E) Zn Since the Zn component has a function of forming a solid solution in the matrix and strengthening it, it is contained as needed when high strength is required, but if the content is less than 0.1%. The desired strength-enhancing effect cannot be obtained, and on the other hand, if the content exceeds 10%, the aggression against the other party will increase.
It was set at 1-10%.

B. Porosity If the porosity is less than 5%, the desired lubrication properties cannot be obtained, while if the porosity exceeds 30%, the strength is extremely reduced, so the porosity is set to 5 to 30%. Specified.

C. Heat treatment temperature If the heat treatment temperature is less than 180 ° C, Sn is economical in actual operation.
-It is difficult to form the Pb alloy layer, while the temperature is
When the temperature exceeds 350 ° C, the bearing will be thermally deformed, so the temperature was set to 180-350 ° C.

D.Sn-Pb alloy layer average layer thickness If the average layer thickness is less than 0.1 μm, the desired excellent conformability cannot be secured, while the average layer thickness is 10 μm.
If it exceeds m, the wear progress is promoted due to the increase of the soft layer, so the average layer thickness is 0.1 to 10μ.
It was defined as m.

〔Example〕

Next, the sintered bearing of the present invention will be specifically described by way of examples.

As a raw material powder, Cu-100 alloy (S
n: 10%) powder, Cu-Pb alloy (Pb: 50% content) powder, P
b-Sn alloy (Sn: 50% content) powder, Cu-Sn-Pb alloy (Sn: 1
0%, Pb: 10%) powder, Cu powder, Sn powder, Pb powder, graphite powder, MoS ₂ powder, Cu-P alloy (P: 10% content) powder, Cu
-Prepare B alloy (B: 5% content) powder and Zn powder,
Each of these raw material powders was blended to the blending composition shown in Table 1, mixed under normal conditions, and then pressed into a green compact at a predetermined pressure within the range of 0.5 to ⁸ ton / cm ² , and then The green compact was sintered in a decomposed natural gas atmosphere at a predetermined temperature within the range of 600 to 800 ° C. to have substantially the same composition as the composition and the porosity shown in Table 1. In addition, a Cu alloy sintered bearing having dimensions of outer diameter: 16 mm × inner diameter: 8 mm × height: 8 mm was manufactured. Sn-Pb alloy layer forming heat treatment under the conditions shown in (this heat treatment utilizes the cooling process after sintering, and is carried out by maintaining at a predetermined temperature within the range of 180 to 350 ° C for a predetermined time during cooling. May be applied) to form an Sn-Pb alloy layer having an average layer thickness also shown in Table 1, and finally subjected to a sizing treatment (this Sizing treatment is line of connexion or) before the Sn-Pb alloy layer forming heat treatment of the porosity : 18% or more was subjected to oil impregnation treatment to manufacture Cu alloy sintered bearings 1 to 30 of the present invention.

Next, the Cu alloy sintered bearing 1 of the present invention obtained as a result
~ 30, and Cu alloy sintered bearings manufactured under the same conditions except that the above Sn-Pb alloy layer forming heat treatment was not performed (since this corresponds to the conventional Cu alloy sintered bearings, for that sintered bearing) 30, mating member: diameter 8mm of S45C (medium carbon steel) manufactured by the shaft, the circumferential speed: 100 m / min surface pressure:. 10 Kgf / cm ^2, the condition subjected to familiar tested of the fixed The running time until the friction coefficient was shown was measured. The results are shown in Table 2. Table 2 also shows the constant friction coefficient.

Further, FIGS. 1 and 2 show metallographic photographs of the sintered alloy bearing 2 made of the present invention and the sintered bearing 2 made of conventional Cu alloy, taken by a metallurgical microscope, respectively.

〔The invention's effect〕

From the results shown in Table 2 and FIGS.
In each of the Cu alloy sintered bearings 1 to 30, the operating time until the Sn-Pb alloy layer formed on the surface reaches a constant friction coefficient is the Sn-Pb alloy layer. It is apparent that the frictional coefficient is relatively shorter and the friction coefficient is lower than that of the conventional Cu alloy sintered bearings 1 to 30 which are not formed.

As described above, according to the method of the present invention, it is possible to manufacture a Cu alloy sintered bearing having excellent conformability, which significantly shortens the conforming operation time, thereby contributing to cost rationalization. There are some great things that can be done, and industrially useful effects are brought about.

[Brief description of drawings]

FIG. 1 is a metallographic photograph of a surface cross section of a Cu alloy sintered bearing according to the present invention, taken by a metallographic microscope, and FIG. 2 is a metallographic photograph of a conventional Cu alloy sintered bearing, which is taken along a metallographic microscope. .

Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display area F16C 33/14 A 7123-3J

Claims (9)

[Claims] 1. A Cu alloy containing Sn: 3 to 20%, Pb: 0.1 to 20%, and the balance consisting of Cu and unavoidable impurities (above wt%), and a porosity of 5 to 30%. On the surface of sintered sintered bearings, soft Sn- with an average layer thickness of 0.1 to 10 μm
Sintered bearing made of Cu alloy with excellent compatibility by elution forming Pb alloy layer. 2. Sn: 3 to 20%, Pb: 0.1 to 20%, and C: 0.1 to 10%, MoS ₂ : 0.1 to 10%, and one or two of However, the average layer thickness on the surface portion of the Cu alloy sintered bearing having a composition of Cu and unavoidable impurities (more than wt%) and the porosity of 5 to 30% is the rest:
Sintered bearing made of Cu alloy with excellent compatibility, which is formed by eluting a soft Sn-Pb alloy layer of 0.1 to 10 μm. (3) Sn: 3 to 20%, Pb: 0.1 to 20%, P: 0.05 to 2%, B: 0.01 to 2%, and one or two of On the surface of a Cu alloy sintered bearing having a composition in which the balance is Cu and unavoidable impurities (above wt%), and a porosity of 5 to 30%, the average layer thickness is:
Sintered bearing made of Cu alloy with excellent compatibility, which is formed by eluting a soft Sn-Pb alloy layer of 0.1 to 10 μm. 4. A composition containing Sn: 3 to 20%, Pb: 0.1 to 20%, Zn: 0.1 to 10%, and the balance Cu and inevitable impurities (above wt%). , And on the surface of a Cu alloy sintered bearing having a porosity of 5 to 30%, a soft Sn-having an average layer thickness of 0.1 to 10 μm.
Sintered bearing made of Cu alloy with excellent compatibility by elution forming Pb alloy layer. 5. Sn: 3 to 20%, Pb: 0.1 to 20%, C: 0.1 to 10%, MoS ₂ : 0.1 to 10%, and one or two kinds thereof are contained, Furthermore, P: 0.05 to 2%, B: 0.01 to 2%, one or two of them are contained, and the balance is composed of Cu and unavoidable impurities (above weight%) and 5 to 30% of porosity The average layer thickness on the surface part of the Cu alloy sintered bearing having the ratio:
Sintered bearing made of Cu alloy with excellent compatibility, which is formed by eluting a soft Sn-Pb alloy layer of 0.1 to 10 μm. 6. Sn: 3 to 20%, Pb: 0.1 to 20%, C: 0.1 to 10%, MoS ₂ : 0.1 to 10%, and one or two kinds thereof are contained, Furthermore, Zn: 0.1-10% is contained, the balance is composed of Cu and unavoidable impurities (above wt%), and the average surface area of the Cu alloy sintered bearing has a porosity of 5-30%. Layer thickness: 0.1-10 μm soft Sn−
Sintered bearing made of Cu alloy with excellent compatibility by elution forming Pb alloy layer. 7. Sn: 3 to 20%, Pb: 0.1 to 20%, further containing one or two of P: 0.05 to 2% and B: 0.01 to 2%, Furthermore, Zn: 0.1-10% is contained, the balance is composed of Cu and unavoidable impurities (above wt%), and the average surface area of the Cu alloy sintered bearing has a porosity of 5-30%. Layer thickness: 0.1-10 μm soft Sn−
Sintered bearing made of Cu alloy with excellent compatibility by elution forming Pb alloy layer. 8. Sn: 3 to 20%, Pb: 0.1 to 20%, C: 0.1 to 10%, MoS ₂ : 0.1 to 10%, containing 1 or 2 types, P: 0.05 to 2%, B: 0.01 to 2%, one or two of them, and Zn: 0.1 to 10%, and the balance Cu and inevitable impurities (above) %), And a Cu alloy sintered bearing having a porosity of 5 to 30%, and a soft Sn-having an average layer thickness of 0.1 to 10 μm.
Sintered bearing made of Cu alloy with excellent compatibility by elution forming Pb alloy layer. 9. A Cu alloy sintered bearing containing Sn: 3 to 20% and Pb: 0.1 to 20% and having a porosity of 5 to 30% in an unconditional atmosphere at 180 to 350 ° C. Performing Sn-Pb alloy elution heat treatment under the condition of heating and holding at a predetermined temperature within the range of
Excellent compatibility, characterized by elution-forming a soft Sn-Pb alloy layer with an average layer thickness of 0.1-10 μm on the surface
Manufacturing method of Cu alloy sintered bearings.