US2145970A - Lubricating bearing surface - Google Patents

Description

Patented Feb. 7, 1939 UNITED STATES LUBRICATING BEARING SURFACE Troy Lee Cantrell and James Otho Turner, Lansdowne, Pa., assignors to Gulf Oil Corporation, Pittsburgh, Pa, a. corporation of Pennsylvania No Drawing. Application June 5, 1936, Serial No. 83,760

1 Claim.

This invention relates to improved methods of lubricating bearing surfaces in internal combustion engines when subjected to conditions of operation which comprises maintaining between bearing surfaces, one of which is an alloy formed chiefly of a metal of the class consisting of cad mium and copper, a mineral lubricating oil which initially produces an efiective lubricating action but which would normally tend to corrode the aforesaid alloy and maintaining the efiectiveness of the lubricating oil by incorporating isoeugenol in a small but sufficient proportion substantially to retard the corrosion; all as more fully hereinafter set forth and as claimed.

Recent developments in the design of mechanical equipment for generating and transmitting conditions imposed by modern engineering de-' sign, these new alloy bearingsarecommonly subjected to more severe operating conditions than were usual in the older art; to higher bearing loads, higher rubbing speeds and higher temperatures of opera tion. It is found that in actual use under these conditions there often develops serious destructive action on the bearing surface by mineral lubricating oils, even by those standard commercial oils giving particularly good results with the older bearing metals under the earlier operating conditions. The destruction of the bearing metal probably results from action of deterioration products developed in the oil. An object achieved in the present invention is the production of lubricating oils improved for these newer conditions of use and which are characterized by reduction or elimination of destructive action on the newer bearing metals by deterioration products in the oil.

We have discovered that isoeugenol, incorporated with the oil, is capable of achieving the objects of the present invention. By adding small amounts of isoeugenol, say 0.05 to 0.40 per cent by weight to the mineral oil or lubricant, we obtain improved lubricating compositions which satisfactorily lubricate the said alloy bearings. Incorporated in mineral oil, isoeugenol retards destruction of the bearing metal. The amounts of isoeugenol necessary to obtain this improvement are such that the initial properties of the oil, such as viscosity, gravity, color, etc., are not substantially altered. Thus, by the present invention, certain properties of the lubricant are improved without sacrificing the other desirable properties of the lubricating oil.

Isoeugenol is a well known chemical compound, being industrially produced in quantity in the manufacture of vanillin. It is l-propenyll-hydroxy-3-methoxy-benzene, having the formula It is a clear, viscous liquid boiling at 267.5 C. and having a specific gravity of 1.091 B. at 15/15 C. Isoeugenol is completely soluble in alcohol and ether, but is only slightly soluble in Water.

Isoeugenol is soluble in and miscible with mineral oils and the like in suflicient proportion to efiect our desired improvement in the oil. by the present invention, we obtain improved mineral oils and petroleum oil lubricantssuitable for lubricating alloy bearings under. a wide range of service conditions; even when there is a free circulation of air.

The isoeugenol may be incorporated withthe mineral oil or lubricating base in any suitable manner. It may be dissolved in the oil by simply mixing it with the oil and slightly warming with agitation to obtain uniform lubricants. Warming to temperatures between F. and 180 F. is suflicient. lubricating oils this Warming is advantageous since the heating lowers the viscosity of the oil and so facilitates the blending. To agitate the mixture, various mechanical agitators may be employed. Also, a current of air may be passed through the mixture to obtain thorough mixin and blending. The isoeugenol may be first dissolved in a suitable lubricating oil to forma master batch which is subsequently blended with more lubricating oil to give a range of lubricating compositions as desired. Likewise the compounded lubricant may be converted into thickened compositions or greases in any of the usual ways. The isoeugenol may be directly added to metal soap grease or other compounded lubricant in which a petroleum oil is the lubricating base.

In the practice of the present invention, any suitable mineral lubricating oil base may be employed, either heavy or light oil. It is best to select a good grade of mineral lubricating oil which has suitable initial properties for the particular. lubrication requirement. The addition of isoeugenol produces the additional desired characteristic of restraining the destructiveness of oil deterioration products toward the newer Thus,

With the heavier and more viscous alloy bearing metals, etc. That is, petroleum oils and lubricants of the usual grades may be employed in practicing this invention. The oils falling within the well known S. A. E. classifications are among those which can advantageously be improved by our invention. Likewise, special lubricants such as obtained by blending certain non-petroleum oils with mineral oil may be improved by the addition of isoeugenol.

The corrosion and pitting of bearing metals by particular oils under drastic service conditions may be readily observed by visual inspection, but a special laboratory test is necessary to readily and quickly determine the destructive action of oil deterioration products on a standard comparable and reproducible basis and to readily evaluate commercial lubricants for such alloy bearings, We have devised a satisfactory accelerated test procedure which is as follows:

An alloy bearing shell of certain commonly used standard dimensions is submerged in 300 cc. of the oil or oil composition in a 400 cc. Pyrex beaker and heated in a thermostatically controlled oil bath to 175 C. (347 F.) and air, at the rate of 2000 cc. per hour, is bubbled through the oil in contact with the bearing shell. At the end of 48 and 96 hours, the loss of weight and the condition of the bearing shell are determined. This test will hereinafter be referred to as our standard laboratory test.

In determining the loss in weight the bearing shell is washed free of oil and dried before Weighing.

When determining the effectiveness of various improvement agents the usual procedure is to run a blank test simultaneously with the oil composition being tested, employing for that purpose a sample of the untreated oil.

In such tests it is advantageous to employ commercial bearing shells. These shells comprise a suitable metal backing faced with the alloy bearing metal, In the above test, the air is bubbled against the alloy bearing face. In this way, the actual bearing face is subjected to severe deteriorative conditions. By comparison of the results of such tests with actual service tests, we have found them to be in substantial agreement as to ,the suitability of particular lubricants. v

In testing our lubricants, we have employed, among others, bearings of the following approximate composition:

1. Cadmium-silver alloy, 7610.

Metal Percent Cadmium 98 Silver 1 Copper 1 2. Lead-copper alloy, 9020 CA.

Metal Percent Such alloys are used in the tests of illustrative improved lubricants given post. In such tests the loss in weight, while not extremely high when expressed as per cent loss, is nevertheless very significant, as the bearing shells used have an alloy facing of only .008 inch to .012 inch thickness on a highly resistant backing and the observed losses in the reported tests often represent a loss of the order of ten per cent of the alloy facing.

The specific examples and tests given post are illustrative of detail embodiments of the present invention.

The specific examples and tests given post are illustrative of detail embodiments of the present invention,

Example 1.-Into a suitable vessel there are introduced 1000 gallons (7200 lbs.) of Pennsylvania motor oil S. A. E. grade and the oil warmed to 160 F. Then 7.2 pounds of isoeugenol (0.10 per cent by weight on the oil) are gradually added and the mixture agitated until a uniform blend is obtained; about 1 hour being required. The improved motor oil is then cooled and packaged into suitable containers. In agitating the mixture, ordinary mechanical agitators may be employed or a current of air may be passed through the warm mixture to produce uniform blending.

The properties of the original and improved motor oil are as follows:

Table A Improved Original oil lubricant Gravity: API Viscosity, SUV:

210 F Flash, 0.0.: T. Fire 0. (1.: F Pour: F 0 0 Color: NPA Carbon residue: Percent Neutralization No Copper strip test Nil i Satisfactory Satisfactory Table B Improved Bearing shell weightlubricant Original oil Grams Before test After test Total change Comment Bearing appearance (after test)- Insignificant No change Badly etched and pitted .S. A. E. 20 grade motor oil in lieu of the particular materials in Example 1, another improved motor oil is obtained It is likewise satisfactory for lubricating these alloy bearings without substantial corrosion. When likewise subjected to the standard test the following results were obtained:

Table 0' Bearing shell weight- Original oil fi g gxg Grams Grams Before test 26. 7291 36. 0561 After test 26. 4205 36. 0560 Total change 0.3086 -0 0001 Comment Significant loss Insignificant loss Bearing appearance (after Badly etched and N 0 change test). pitted The above examples are but illustrative embodiments of the present invention and in practice other embodiments may be used. That is, the percentage of isoeugenol added to the lubricant to improve it may be varied, as indicated, according to the particular properties desired in the final lubricant and the lubricating base used. Likewise, the lubricating base itself may be selected according to the type. of the final lubricant to be produced. For instance, any of the usual greases or the usual blends of mineral and blown fatty oils may bejemployed as the lubricating base in making lubricants of those types. When incorporating the isoeugenol in a grease composition or like thickened lubricants, mechanical agitators rather than a current of air are employed to obtain uniform mixing and blending. That is, the isoeugenol and the grease may be compounded in the usual mixtures such as blade mixers equipped with heating jackets. However, in making such greases the isoeugenol may be first incorporated with the oil base according to the procedure of Example 1 and then the metal soap or other thickened agent added .to the improved oil, in the ordinary way to produce the desired grease composition. In other words, the improved mineral oil of the present invention may be used in lieu of the ordinary oils in making spcecial lubricating compositions such as greases, e

as stated ante, the incorporation of isoeugenol with the lubricating base produces several improvements in the final lubricant without deleteriously afiecting the desirable properties. While the exact reasons for the improvements obtained are not fully known, we are satisfied with observing and utilizing the actual improvements obtained by adding and incorporating isoeugenol with commercial lubricants.

Isoeugenol alone is a highly effective improvement agent for mineral lubricating oil, and we also find it useful as an assistant to numerous other so-called improvement agents, and its use in conjunction with other so-called improvement agents which have-unpleasant odors is especially desirable because the pleasant odor of isoeugenol tends to screen any unpleasant odors which may be present.

The use as improvement agents of materials which contain either sulfur or chlorin or both in their chemical constitution is known. But both sulfur and chlorin, present in this matter, are found undesirable under certain conditions of use, and our use of.isoeugenol as an improvement agent for mineral lubricating .oils completely avoids the undesirable effects just referred to.

The addition of isoeugenol to lubricating oil not only has utility, as described at length herein, but it also imparts to the oil a pleasant characteristic non-petroleum odor.

What we claim is: I

A method of lubricating bearing surfaces in internal combustion engines when subjected to conditions of operation which-comprises maintaining between bearing surfaces, one of which is an alloy formed chiefly of a metal selected from the class consisting of cadmium and copper, a film of lubricating oil which initially produces an efiective lubricating action but which would normally tend to corrode the aforesaid alloy, and maintaining the effectiveness of the lubricating oil by incorporating therein isoeugenol in a small but suflicient proportion substantially to retard the corrosion.

TROY LEE CANTREIL. JAMES O'I'HO TURNER.