JPH05209623A - Sintered oil-impregnated bearing - Google Patents

Abstract

(57) [Summary] [Object] The present invention enables a sintered oil-impregnated bearing to be used as a substitute for a rolling bearing in a high temperature atmosphere, even under severe conditions in which thrust and radial loads are simultaneously applied. Maintain stable friction characteristics for a long time and be durable. [Composition] Alkyl diphenyl ether oil and poly-α-olefin oil are added to a sintered bearing molded product in a weight ratio of 80: 2.
The sintered oil-impregnated bearing is impregnated with the mixed oil blended in the range of 0 to 20:80.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sintered oil-impregnated bearing obtained by impregnating a sintered bearing molded product with lubricating oil.

[0002]

2. Description of the Related Art Generally, a sintered oil-impregnated bearing has long-term stable friction by allowing lubricating oil to be impregnated and held in the pores of a sintered bearing molded product and allowing the lubricating oil to exude to the sliding surface during use. It is intended to obtain characteristics.

Molded products of such sintered bearings are usually
Fine powder particles made of iron, copper, zinc, tin, graphite, nickel, lead, etc. or alloys combining these are mixed, compression molded,
It is obtained by subjecting it to treatments such as firing and sizing, and it has a uniform porous structure.

As the lubricating oil impregnated into the sintered bearing molded product, a synthetic lubricating oil such as mineral oil or diester oil has been used.

A sintered oil-impregnated bearing made of such a material is generally less expensive to manufacture than a rolling bearing, so that it can be used in a high temperature atmosphere such as a bearing for a cooling fan motor for an automobile. The range of applications is expanding to the applications used in.

[0006]

However, 120 to 13
If the conventional oil-impregnated sintered bearing is used in a high temperature atmosphere of 0 ° C. or higher, deterioration of the lubricating oil such as oxidation will occur rapidly over time, and the torque of the rotating shaft will increase early after use. However, there is a problem that burn-in occurs.

Further, in order to use the sintered oil-impregnated bearing as a substitute for the rolling bearing, it is necessary to support the thrust load on the bearing end face via the washer. At this time, the lubricating oil to be impregnated is required to have the required lubricating characteristics, extreme pressure properties, and thermal stability against frictional heat, but there is a problem that there is no sintered oil-impregnated bearing using a lubricating oil that satisfies these requirements. is there.

The present invention solves the above-mentioned problems and allows a sintered oil-impregnated bearing to be used as a substitute for a rolling bearing in a high temperature atmosphere so that it is subjected to harsh conditions in which thrust load and radial load are simultaneously applied. It is an object to maintain stable friction characteristics for a long time even under the condition of being durable.

[0009]

In order to solve the above-mentioned problems, in the present invention, a sintered bearing molded product contains an alkyldiphenyl ether oil and a poly-α-olefin oil in a weight ratio of 80:20 to 20:80. It was impregnated with the mixed oil blended within the range. The details will be described below.

The sintered bearing molded product is not particularly limited in its material, and is a product obtained by sequentially molding a required metal material through a compression molding process, a sintering process and a compression shaping process as in the conventional case. May be

The poly-α-olefin oil (hereinafter abbreviated as PAO) used in the present invention is obtained by low-polymerizing an α-olefin,
It has a structure in which hydrogen is added to the terminal double bond, and the structure shown in the following formula can be exemplified.

[0012]

[Chemical 1]

The alkyl diphenyl ether oil (hereinafter abbreviated as DAPE) used in the present invention is obtained by an addition reaction of 1 mol of diphenyl ether and 1 to 3 mol of an α-olefin having 10 to 22 carbon atoms.
The properties vary depending on the number of carbon atoms and the number of moles of the α-olefin used.

The mixing ratio of DAPE and PAO is as follows.
DAPE: PAO is 80:20 to 20:80 by weight.
The range is. Because, in excess of the above specified mixing ratio,
This is because if either one is excessively large and the other is excessively small, the friction coefficient is not sufficiently reduced and the intended purpose of the present invention cannot be achieved.

It is needless to say that various additives such as antioxidants, viscosity index improvers and oiliness improvers may be added to the lubricating oil used in the present invention as long as the effects of the invention are not impaired. ..

[0016]

[Examples] The lubricating oils used in Examples and Comparative Examples are summarized below.

Alkyl diphenyl ether oil [DA
PE] manufactured by Matsumura Oil Co., Ltd .: BS100 poly α-olefin oil [PAO] manufactured by Mitsui Petrochemical Co., Ltd .: HC10 diester oil: manufactured by Toyo Kokusai Oil Co., Ltd .: Anderol 465 polyol ester oil: manufactured by Ciba Geigy Co .: Rheorube LPE602 [Examples 1 to 3 and Comparative Examples 1 to 4] The above lubricating oils were blended at the blending ratio (wt%) shown in Table 1, and the friction coefficient was measured using a Savan type friction and wear tester for Examples 1 to 3 and Comparative Examples 1 and 2. I asked. In addition, in Example 2 and Comparative Example 3, the change with time of the total acid value of the lubricating oil (the sample was dissolved in an alcohol / ether solvent and titrated with 0.5N potassium hydroxide using phenolphthalein as an indicator) 150 ° C.) was measured. These results are shown in the graphs of FIG. 1 and FIG. 2, respectively.

[0018]

[Table 1]

As is clear from the value of the friction coefficient in FIG.
Comparative Example 1 and PA containing no lubricating oil PAO
In Comparative Example 2 in which O was 100% by weight, the friction coefficient was 0.06 or more. On the other hand, in Examples 1, 2 or 3 in which PAO was 20, 50 or 80% by weight, respectively, the friction coefficient was a low value of less than 0.06.

Further, as is clear from the change with time in the total acid value of FIG. 2, the diester oil used as the lubricating oil in Comparative Example 3 had an increase in the total acid value with time from the beginning of the test. DAPE: PAO = 50: 5 used in Example 2
It was found that the value of the lubricating oil of 0 increased only after 500 hours, and the deterioration rate of the lubricating oil in a high temperature atmosphere was low.

Next, a bearing molded product obtained by sintering a metal material containing iron as a main component was dipped in a lubricating oil prepared in the mixing ratio shown in Table 1 to impregnate it, and the obtained sintered oil-impregnated bearing was manufactured. The following durability tests were conducted on Examples 1 to 3 and Comparative Examples 3 and 4.

Durability test: The sintered oil-impregnated bearing 1 was mounted on the torque measuring device shown in FIG. 3, and an axial load (elastic force of the compression spring 2) and a radial load (load of the housing 3) were applied thereto. . That is, two cylindrical sintered oil-impregnated bearings 1 press-fitted at both ends of a cylindrical housing 3 were attached to a shaft 5 (shaft diameter 6 mm) which is rotated by a drive belt wound around a pulley 4. At this time, the end surface of the sintered oil-impregnated bearing 1 was pressed by a pair of thrust washers 6 and 7 which rotated together with the shaft 5 and urged in the direction of the shaft 5 by the compression spring 2.
Further, a torque measuring thread 8 was fixed to the outer periphery of the housing 3 to measure the torque. The measurement conditions were an axial load of 0.2 kgf, a radial load of 0.2 kgf, a rotation speed of 4000 rpm, an ambient temperature of 120 ° C., the number of tests n = 4 for each sample, and the time when the torque was 80 g-cm or more was the life. It was time. The results are shown graphically in FIG.

As is clear from the life time of FIG. 4, in Comparative Example 3 impregnated with diester oil and Comparative Example 4 impregnated with polyol ester oil, there was nothing that could withstand up to 900 hours, but Examples 1 to 3 Then, 1200-170
The durability was as long as 0 hours, and in particular, the durability was about 10 times that of Comparative Example 3.

[0024]

As described above, the present invention uses a mixed oil in which an alkyl diphenyl ether oil and a poly-α-olefin oil are blended at a predetermined ratio and impregnates the mixed oil into a sintered oil-impregnated bearing. It has the advantage that it can withstand long-term use even under severe conditions where it is subjected to thrust load and radial load at the same time in an atmosphere, and that it is possible to substitute rolling bearings with sintered oil-impregnated bearings that are excellent in productivity and can be manufactured at low cost. There is.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the friction coefficient and the blending ratio of poly-α-olefin oil.

FIG. 2 is a graph showing changes in total acid value over time.

FIG. 3 is a vertical sectional view showing a torque measuring device for a durability test.

FIG. 4 is a graph showing life times of examples and comparative examples.

[Explanation of symbols]

 1 Sintered oil-impregnated bearing 2 Compression spring 3 Housing 4 Pulley 5 Shaft 6, 7 Thrust washer 8 Thread

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Claims (1)

[Claims] 1. A sintered bearing molded product containing alkyl diphenyl ether oil and poly-α-olefin oil in a weight ratio of 8: 1.
A sintered oil-impregnated bearing impregnated with a mixed oil blended in a range of 0:20 to 20:80.