US2004708A - Bearing metal and bearing - Google Patents

Description

June l1, 1935. c, PFANsTlEHL BEARING METAL AND BEARING Filed oct, lo 1931 Patented .Func Il, 1955 aoomos BEARING METAL AND amuse.'

Carl Pfanstiehl, Highland Park, Ill., or to Pfanstiehl Chemical Company, a corporation of Illinois The present invention relates to improvements in bearing metals and bearings, more particularly formed from alloys or metallic aggregates consisting primarily of copper and lead. It will be fully understood from the following description illustrated by lthe accompanying drawing, in which: v

Figure 1 illustrates diagrammatically and on greatly enlarged scale amicroscopic structure of a copper-lead alloy or mixture as employed in the preparation of bearing metals and -bearinss:

Fig. 2 shows in similar manner the microscopic structure of such metal after the preliminary superficial treatment in accordance with the present invention; and

Fig. 3 illustrates in a similar manner the microscoplc structure of the bearing surface or metal prepared in accordance with the present invention.

In the preparation of a bearing metal or bearing surface in accordance with the present invention, a metallic alloy or aggregate is employed consisting principally of copper and lead in intimate admixture. Such alloys or mixtures may contain from 5 to 50% of lead, a suitable alloy produced in accordance with the present invention containing, for example, '70% copper and lead. v

In the use of such bearing metals, the constituents are ordinarily melted `together in the desired proportions, and cast to form a bearing surface of the desired conformation, sometimes against a supporting backing of harder metal,

such as steel. On casting and rapidly cooling such mixtures, the lead takes the form of irregular inclusions in a copper network, as seen on microscopic study of the resulting mixture. Thus, as shown on enlarged scale diagrammatically in Fig. 1, the numeral 5 represents the copper network present in the bearing metal and the numeral 6 the irregular lead inclusions, the numeral l indicating the bearing surface.

In accordance with the present invention, I

apply to the bearing surface a suitable selective solvent capable of attaching and converting the copper into a readily solvent form without affecting the lead. I may employ for this purpose. .for example, a solution of ammonium trichloracetate, preferably made somewhat alkaline with ammonia. I may prepare such a solution, for example, by adding 90 parts by weight of concentrated ammonia solution to a solution of 20 parts by weight of trichloracetic 56 acid in 100 parts by weight o f water.

gWED STATES PATENT -order .0002-.001 inch.

After suitable washing, for examplewlth alcohol, soap and water or the like to remove traces oi' grease which may be present on the surface to be treated, and drying, the bearing surface of the metal .is subjected to the action of 5' the selective copper solvent, which is permitted to act until a desired penetration of the bearing surface and removal of copper'is secured.. say to the extent'of 0.0005 to 0.003 inch. The bearing surface is then washed, suitably with 10 alcohol, and dried, preferably under a vacuum. As a result of this treatment, the copper present at the bearing surface of the metal is removed to the desired extent, leaving on the surface the projecting lead fibers originally included in the 15 copper network, these fibers being continuous with lead constituents of the body of the metal. The bearing surface after this treatment is illustrated diagrammatically in enlarged scale in Fig. 2, where the numeral liHL indicates the fibrous 20 lead at the treated surface of the metal, originally present as inclusions inthe copper network.

The bearing surface is then burnished or polished, suitably by rubbing or lapping in the jour- 25 nal or shaft with which it is to be associated. As a result ofthe rubbing action, the fibrous lead projections at the surface of the bearing metal are quickly compressed and burnished to form a. substantially continuous lead bearing surface, 30 which conforms to the shaft so quickly as to minimize the chance of injuring the shaft in running in", as shown, at 6b in Fig. 3. By proceeding in this manner, the lead which is spread over the copper constituent wets the copper and forms 35 an intimate bond therewith.

As a result of this' treatment a surface layer of lead is produced having a thickness of the If desired, an additional lubricant material. 40 such as oil, graphite or the like, may be applied to the bearing surface after the treatment to remove the copper, the added lubricant being thoroughly incorporated in the lead surface 6'J in the nal step of the process, in which the lead is 45 formed into a continuous bearing surface. For example, an intimate suspension of graphite in oil may be applied to the bearing surface prioi. to and during the rubbing or lapping in of the bearing, the minute colloidal particles of graph- 50 ite and some of the oil being thereby intimately incorporated with the 'lead in the bearingsurface. Or, if desired, after removal of the copper, the bearing maybe rotated upon its own axis and a suspension of graphite ln oil fed to it, whereby the graphitic material is forced by centrifugal action into the interstices between ythe lead fibers, a vacuum beingmaintained during this operation, if de slred, to facilitate the removal of air or gas from these interstlces. The bearing surface may then be burnished or the shaft which the bearing is to support may be rubbed or lapped in as hereinbefore described.

In place of the solvent above set forth, other selective solvents for the copper may be employed; for example, nitric acid of suitable coni 'centration or hydrochrolic acid. In case hydrochloric acid is employed, the treated surface should be carefully washed with hot water t'o effect the removal of any Dead chloride that may be formed.

I may incorporate other metals in minor proportions to modify the physical properties of the constituents of the alloy and of the alloy itself. For example, minute proportions of alkali or alkaline earth metals, such as sodium, lithium or calcium, varying from 0.05`to `0.75% may be incorporated in the lead constituents of the alloy, as may minute proportions of antimony, tin, zinc or the like.

I claim:

1. The method of forming a bearing surface which comprises subjecting a surface of a metal consisting principally of a copper constituent and a lead constituent to the action of a selective copper solvent, thereby effecting superficial removal of the copper constituent thereof, and forming the remaining lead constituent at said surface into a continuous bearing surfac'e.

2. The method of forming a bearing surface which comprises subjecting a surface of a bearing metal consisting principally of a copper constituent and a lead constituent to the action of a selective solvent for the copper, thereby supercially removing a portion of the copper constituent of the metal, and forming the remaining lead constituent into a continuous bearing surface in the presence of a lubricant material.

3. The method of forming a bearing which comprises shaping a copper-lead mixture to provide a bearing surface, applying a selective copper solvent to said bearing surface to remove the copper superilcially thereof, and rubbing and compressing vthe surface to form the remaining lead into bearing surface.

4.The method of forming a bearing surface which comprises subjecting a surface of a bearing metal consisting principally of a. copper con stituent and a lead constituent to the action of a selective solvent for the copper, thereby superflcially removing a portion of the copper constituent of the metal, applying graphitic material to the surface so formed, and forming the remaining lead constituent into a continuous bearing surface. whereby a portion of said graphitlc material .is incorporated within said lead surface and intimately admixed therewith.

5. The method as set forth in claim 4, in which the remaining lead constituent is formed into a continuous bearing surface by rubbing and compressing the surface.

6. A bearing comprising a body portion of a metal consisting principally of copper and lead and having the copper etched away at the bearing surface to a depth of the order of .0005 to .003 inch.

7. A bearing as in claim 6 in which the lead comprises 5`to 50% of the metal.

8. A bearing as in claim 6 in which the lead and copper are in a ratio of the order of 30 parts lead to 70 parts copper.

9. A bearing comprising a body portion of a metal consisting principally of copper and lead and containing 5 to 50% lead by weight segregated in small bodies, the copper areas adjacent to the bearing surface being roughened as by etching; the bearing surface being composed substantially of lead mechanically bonded to the roughened copper' areas. and being molecularly continuous with the lead bodies of the body portion.

l0. A bearing as in claim 9 in which the lead and copper are in a ratio of the order of 30 parts lead to '70 parts copper.

11. A bearing as in claim 9 in which the bearing surface has a thickness of the order of .0002

to .001 inch.

12. A bearing as in claim 9 in which the lead of the bearing surface includes graphite in very' intimate admixture with the lead..

CARL PFANsTIErn..

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