Solid lubricant applied to porous roller bearings prior to use in ultrahigh vacuu

Glenn, D. C.

English

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NATIONAL AERONAUTICS AND SPACE -ADMINISTRATION 
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November 6, 1970 
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Attentions Miss Winnie MI Mozgan 
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March 17, 1970 D. G.  G L E N N  
HEAT 
RlETWBD OF LidDRIGATING ROLLSING ELEMENT BEARINGS 
Filed Nov. 28, 2.967 
BEARING INNER RACE METAL OUTER RACE 
RETAINER ROLLING ELEMENTS 
HYDROGEN 
FURNACE: CLEAN 
ACETONE & 
APPLY 
LUBRICANT 
ASSEMBLE 
COMPONENTS 
ROTATE 
BEARING 
REASSEMBLE 
iisdVEltBT(aR 
BEAN C.GLENN 
ATTORNEYS 
3,500,525 United States Patent O6s.e Patented Mare 1970 
1 2 
DESCKIP1 ION OF THE PREFERRED 
3,500,525 EMBODIMENT 
METHOD OF LUBRICATING ROLLING 
ELEMENT BEARINGS A bearing made in accordance with the invention has 
Dean C. Glenn, League City, Tex., assignor to t l ~ e  United rolling elements, such as balls or rollers, spaced by a 
States of America as represented by the Administrator retainer or cage. Both the rolling elements and the re- 
of the National Aeronautics and Space Administration tainer are positioned between an outer race and an inner 
Filed Nov. 28, 1967, Ser. No. 686,344 race in a conventional manner. The races and rolling ele- 
Int. CI. B21d 53/12 ments are preferably fabricated f ~ o m  440 stainless steel. U.S. CI. 29-148.4 'Iaims However, other suitable bearing steels may be utilized. 
In accordance with the present invention, the retainer 
ABSTRACT OF THE DISCLOSURE or cage is fabricated from porous bronze or copper-tin 
alloy. Contaminants, such as oils or other organics, are 
A solid film lubricant is applied to components of roll- removed from the retainer after fabrication. This is ac- 
ing element bearings having porous retainers prior to  use 15 complished by placing the retainer in a hydrogen furnace 
in a vacuum. at a temperature of 1200 to 1400' F. Care is taken to 
make certain that no contaminants contact with the re- 
ORIGIN OF THE INVENTION tainer after cleaning and prior to bearing assembly. The inner race, outer race, and rolling elements are cleaned 
The invention described herein was made by an em- 20 first with acetone and then with-alcohol. 
ployee of the United States Government and may be manu- A solid film lubricant is then applied to all of the 
factured and used by or for the Government for govern- bearing components in preparation for vacuum operation. 
mental purposes without the payment of any royalties It  has been found that burnishing with a wire brush is 
thereon or therefor. satisfactory for this application. 
BACKGROUND O F  THE INVENTION Molybdenum disulfide is preferably applied in this 25 manner. However, other solid film lubricants may be 
This invention is concerned with improved rolling ele- burnished onto the components. These include molyb- 
ment bearings for use in ultrahigh vacuum environments. denum diselenide, tungsten disulfide, tungsten diselenide, 
The invention is particularly directed to such bearings niobium disulfide and niobium diselenide. 
which are capable of providing low torques and a small 30 The bearing is then assembled in a conventional man- 
temperature rise during operation. ner. Additional burnishing of inaccessible regions, such 
Solid lubricants have been used for lubricating rolling- as the rolling element pockets in the cage, is accom- 
element bearings in vacuum operations. The retainer or plished by forcing an air-molybdenum disulfide mixture 
cage which was fabricated from a solid lubricating ma- into the bearing while it is rotating. 
terial functioned to space the rolling elements and to pro- 35 The bearing is then disassembled, and the excess solid 
vide lubrication. Thin films of the retainer material were film lubricant powder is removed by wiping. The bearing 
transferred to the rolling elements by the rubbing action of is then reassembled for use in a vacuum environment. 
the elements in the retainer pocket as the bearing rotated. What is claimed is: 
The lubricant was subsequently transferred by the roll- 1. A method of lubricating components of a bearing 
ing elements to  the inner and outer bearing races. Mate- qo having rolling elements spaced by a retainer between an 
rials used for such retainers were reinforced and filled outer race and an inner race for use in a vacuum com- 
plastics, such as glass filled polytetrafluoroethylene. prising the steps of 
High bearing torques and high operating temperatures heating said retainer to 1200' F. to 1400' F. to free the 
were encountered in these prior art bearings. Optical sys- same from contaminants, 
tems and electronic components malfunctioned because of 45 cleaning said inner race, outer race, and rolling ele- 
contamination by the bearing lubricant. ments with acetone, 
cleaning said inner race, outer race, and rolling ele- 
SUMMARY O F  THE INVENTION ments with alcohol, 
~h~~~ problems have been solved by a rolling element burnishing a solid film lubricant onto said bearing com- 
bearing constructed in accordance with the present in- 50 POnents$ 
~h~ bearing has rolling elements positioned by assembling said retainer and rolling elements between 
a retainer or cage fabricated from a porous metal. A said inner and outer races, 
solid lubricant is burnished on the components. additionally burnishing inaccessible regions by forcing 
an air-solid film lubricant into the bearing subsequent 
OBJECTS O F  THE INVENTION 56 to assembly of said components while said bearing is rotating, 
It is, therefore, an object of the present invention to disassembling said bearing components, 
lubricate a rolling element bearing for operation in an removing the excess solid film lubricant powder by wip- 
ultrahigh vacuum environment of about 10-" torr. ing, and 
Another object of the invention is to provide an im- reassembling the components of the bearing for use in 
p~oved rolling element bear~ng foor opetat~ng at low 60 a vacuum environment. 
to1 C J L I ~ S  and small tenireraiure I ises 2. A method of lubricating components of a bearing 
A method of lubricating a further object of the inven- as claimecl in claim 1 including 
tion is to provide a bedrlrng fon use in an ultrahigh vhcuunl fabricating the retainer component from a porous metal. 
environment which does not require containers, bames or 3. A method of lubricating components of a bearing 
labyrinths to restrict evaporative losses. 65 as claimed in claim 2 including the step of 
These and other objects and advantages of the inven- fabricating the retainer from porous bronze. 
tion will be apparent from the specification which follows. 4. A method of lubricating components of a bearing 
DESCRIPTION O F  THE DRAWING as claimed in claim 1 including the step of selecting a solid film lubricant from the group consist- 
The drawing is a flow sheet illustrating diagrammatically ing of molybdenum disulfide, tungsten disulfide, and 
a process embodying the invention. niobium disulfide. 
3,500,525 
3 4 
5. A method of lubricating components of a bearing 2,593,793 7/1959 R y s I ~ a ~ y  ----------- 29-149.5 
as claimed in claim P including the step of 2,978,793 4'1961 Lamson el al. 
selecting the solid film lubricant from the group con- 2,980,987 4/1961 Lamson et al. 
sisting of molybdenum diselenide, tungsten disele- 3,001,838 9/1961 Lamson et al. ----- 308-241 X 
nide, and niobium diselenide. 3,027,626 4/1962 Murphy. 
' 3,387,985 6/1968 Huber ------------- 29-149.5 
References Cited 
UNITED STATES PATENTS THOMAS H. Primary Examiner 
2,280,886 4/1942 Brace ------------ 308-240 X U.S. C1. X.R. 
2,697,645 12/1954 Mitchell ----------- 308-241 lo 308-240,241 


Method of lubricating rolling element bearings Patent

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