JPS59107006A - Two-layered oil-impregnated bearing made of sintered fe material and its production - Google Patents

Abstract

PURPOSE:To provide a bearing which suppresses the outflow of the oil impregnated therein during running and has a long life by comprising the same of an outside layer having the inside pores packed airtightly with the copper metal infiltered from an inside layer and the inside layer made porous by said infiltration. CONSTITUTION:A two-layered green compact is produced from a ferrous green compact part for forming an inside layer compounded with about 5-35% copper by weight and if necessary about 0.01-4.0% >=1 kinds of phosphorus and tin and a ferrous green compact part for forming an outside layer wherein the amt. of the copper compounded is small relatively with said part or is nil. When such green compact is sintered, the copper or copper alloy in the green compact part for forming the inside layer is infiltered into the green compact part for forming the outside layer by capillarity. A blank material for a two-layered bearing made of the sintered ferrous material consisting of the outside layer wherein the open pores are decreased by the copper or copper alloy infiltered therein to be made airtight and the inside layer which is made porous by the infiltration and migration of the copper or copper alloy to the outside layer and is in axial contact therewith is thus obtd. The compounding of phosphorus and tin accelerates the infiltration and migration of the copper or copper alloy.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an oil-impregnated bearing made of Fe-based sintered material and having a two-layer structure of a relatively airtight outer layer and a shaft-contacting inner layer with high oil retention capacity. It concerns the manufacturing method.

In general, it is well known that oil-impregnated bearings made of Fe-based sintered materials are used in large quantities in household electrical appliances such as electric fans, automobile equipment, and the like.

Oil-impregnated bearings have oil impregnated into the open pores (hereinafter referred to as open pores) formed in the Fe-based sintered material and are used without oil in a self-lubricated state. However, the impregnated oil tends to flow out through the open pores during operation, and as a result, the oil pressure at the contact surface between the shaft and the bearing decreases, and the force of the oil supporting the shaft decreases. Localized contact, which causes sticking and seizure, began to occur, and the service life was reached in a relatively short period of time.

Therefore, from the above-mentioned viewpoint, the present inventors conducted research to obtain an impregnated bearing made of Fe-based sintered material that suppresses the outflow of impregnated oil during operation, and found that at least Cu:5
The inner layer-forming Fe-based green compact portion has a blending composition of ~35% by weight, and the Cu content is relatively low compared to the inner layer-forming Fe-based green compact portion, or Cu
When sintering a two-layer green compact consisting of an outer layer-forming Fe-based powder compact having a composition in which no Cu or Cu is added to the inner layer-forming Fe-based powder compact, Since the alloy is infiltrated into the Fe-based compact for forming the outer layer by capillary action, open pores are reduced by the infiltrated CU or CU gold alloy, resulting in an airtight outer layer and the outer layer. A two-layer bearing material made of Fe-based sintered material is obtained by infiltration and movement of CU or Cu alloy, and a porous inner layer of the shaft abutting material is obtained. One or both of P and Sn is added to either or both of the compacted powder parts of the system.
When blended at a ratio of 01 to 40% by weight, the fluidity of molten Cu or Cu alloy during sintering is further improved, and the infiltration movement of molten Cu or Cu alloy to the outer layer is prevented. Furthermore, if the particle size of the raw material powder constituting the Fe-based compact for forming the outer layer is made finer than the particle size of the raw material powder constituting the compact for forming the inner layer, the same effect can be achieved. Molten CU and CU gold alloy infiltration into the outer layer becomes active, further improving airtightness, and the two-layer bearing material made of Fe-based sintered material produced in this way is impregnated with oil. The resulting two-layer oil-impregnated bearing made of Fe-based sintered material allows the impregnated oil in the inner layer, which has become relatively porous and has an increased oil storage capacity, to pass through the outer layer due to the airtight outer layer. They obtained the knowledge that the outflow of foreign substances to the outside world was significantly suppressed.

This invention was made based on the findings described in Section 2, and the reason why the Cu content and the P and Sn content were limited to the above-mentioned values will be explained below.

(al Cu The content of Cu in the Fe-based green compact for forming the inner layer is 5
C in the two-layer bearing material made of Fe-based sintered material
In addition to insufficient airtightness due to U or Cu alloy infiltration, porosity formation due to infiltration movement of molten Cu or Cu alloy in the inner layer to the outer layer is also insufficient, and the desired oil storage capacity is not achieved. On the other hand, if more than 35 inches is added, the amount of liquid phase during sintering becomes too large, resulting in a decrease in strength and deformation. It was set at 35%.

(blp and Sn) These components promote the infiltration of the molten Cu in the inner layer into the CU gold alloy outer layer, further improving the airtightness of the outer layer, and as a result, the inner layer Since it has the effect of increasing porosity and oil retention capacity, it is added as necessary, but if the amount added is less than 0.01%, the desired effect cannot be obtained; If the amount is exceeded, the strength and toughness of the product will deteriorate, so the amount to be added is set at 0.01 to 40%.

Next, the present invention will be specifically explained with reference to Examples.

As the raw material powder for the examples, Cu with a particle size of -150 mesh was used in each case.
Powder, N1 powder, MO powder, Sn powder, Cu-P alloy (P: 0.1% content) powder, Cu-P alloy (P: 10
) powder, Cu-Sn alloy (containing Sn: 0.1%) powder, and Cu-Sn alloy (containing Sn: 11%) powder.

Then, prepare Fe powder with a particle size of -100 mesh, and use these raw material powders to form an Fe-based compact for forming an outer layer and an Fe-based compact for forming an inner layer, each having the composition and layer thickness shown in Table 1. consisting of a powder part and an outer diameter
18mmφ x inner diameter 28Mφ x length.

4 ton/2-layer green compact with dimensions of 181nfn
After molding at a molding pressure of ffl, these two-layer green compacts were debindered at a predetermined temperature within the range of 400 to 600°C in an ammonia decomposition gas atmosphere, and then 1000 to 1150°C in an ammonia decomposition gas atmosphere. Made of Fe-based sintered material 2 by sintering at a predetermined temperature within the range of 80 minutes.
A two-layer oil-impregnated bearing made of the Fe-based sintered material of the present invention (hereinafter referred to as the two-layer sintered oil-impregnated bearing of the present invention) is obtained by forming a layer bearing material (hereinafter referred to as a two-layer sintered bearing material) and subsequently performing sizing and oil impregnation treatment. 1 to 12 were produced, respectively.

Next, the resulting two-layer sintered oil-impregnated bearings 1 to 1 of the present invention will be described.
A wear test was conducted on No. 12 under the following conditions. That is, with the bearing fitted and fixed in a horizontally arranged cylindrical guide, material: S45C, surface roughness: IS
Below, a shaft with a clearance of 25-30 μm is installed through the bearing, and a weight of 15 kg is attached to the bearing via the guide.
The shaft is moved at 150m/m while applying a load of /mrl.
The bearing was rotated at a speed of m, and the maximum wear depth on the shaft abutting surface of the bearing was measured after 60 minutes. The measurement results are shown in Table 1.

Table 1 also shows C: 02% for the purpose of comparison.

A conventional Fe powder was produced by sintering, sizing, and oil-impregnating a single-layer green compact of the same size with a blending composition of N1: 2%, Cu: 2%, and Fe: balance 9 under the same conditions. One-layer oil-impregnated bearing made of sintered material (hereinafter referred to as conventional 1)
We have shown the results of a wear test under the same conditions for a layer sintered oil-impregnated bearing.

Furthermore, Table 1 shows the depth from the outer circumferential surface of the two-layer sintered bearing material, the IM range (outer layer), and the depth from the inner circumferential surface.
The Cu content and density ratio in the 2u range (inner layer) are also shown.

From the results shown in Table 1, the present invention double-layer sintered oil-impregnated bearing 1
~ In process 2, the outer layer is infiltrated with Cu or Cu alloy from the inner layer, reducing open pores and becoming airtight, and the density ratio is significantly improved, preventing impregnated oil from leaking to the outside during operation. The layer on one side has become porous due to the infiltration of Cu or Cu alloy into the outer layer, increasing its oil holding capacity, so it exhibits excellent wear resistance. In contrast, conventional single-layer sintered oil-impregnated bearings can be used in a relatively short period of time due to the outflow of impregnated oil through open pores. It is clear that seizure occurs and the service life is reached.

As described above, according to the present invention, the outer layer is made airtight by reducing open pores due to Cu or Cu alloy infiltrated from the inner layer, and the infiltration movement of Cu or Cu alloy to the outer layer It is possible to manufacture a two-layer oil-impregnated bearing made of Fe-based sintered material, which consists of a shaft abutting inner layer that is porous and has an increased oil holding capacity. The outer layer prevents the impregnated oil from flowing out during operation, and the inner layer ensures a relatively large oil storage capacity, so the bearing exhibits excellent bearing performance over an extremely long period of time. be.

Applicant: Mitsubishi Metals Corporation

Claims (2)

[Claims] (1) an outer layer whose pores are filled with Cu or Cu alloy infiltrated from the inner layer and become relatively airtight; and an outer layer which becomes substantially porous due to the infiltration movement of Cu or Cu alloy to the outer layer; A two-layer oil-impregnated bearing made of Fe-based sintered material, characterized by having an increased oil storage capacity and an inner layer in contact with the shaft. (2) At least Cu: 5 to 35% by weight is blended,
Furthermore, if necessary, one or two of P and Sn may be added.
Fe-based compacted powder part for forming an inner layer having a compounding composition containing 001 to 4.0% by weight of seeds, and the F for forming an inner layer.
Is the Cu content relatively low compared to the e-based green compact part?
Alternatively, Cu is not blended at all, and if necessary, one or two of P and Sn: 001 to 4.0% by weight
A two-layer compact consisting of a Fe-based powder compact for forming an outer layer having a blending composition of
Made of Fe-based sintered material, consisting of an outer layer made airtight by infiltrated CU or Cu alloy, and an inner layer in shaft contact made porous by infiltration and movement of Cu or Cu alloy into the outer layer. A method for manufacturing a two-layer oil-impregnated bearing made of Fe-based sintered material, characterized by manufacturing a two-layer bearing material.