Reliability roller bearing

An improved reliability roller bearing having an outer ring; inner ring made up of three separable elements, that is, two guide rails and an inner raceway; a plurality of rollers interposed between the inner ring and the outer ring and a cage for supporting the rollers therebetween. Both guide rails entrap up to 60% of the roller diameter. In addition, the roller bearing incorporates therein a novel lubricant distribution system which is formed within the guide rails. Even distribution of lubricant is obtained by a centrifugally fed weir built into both guide rails.

BACKGROUND OF THE INVENTION 
This invention relates generally to high speed antifriction bearings, and, 
more particularly, to a roller bearing of improved reliability. 
In general, an antifriction bearing of the roller bearing type finds its 
greatest utility by being interposed between a stationary and a rotating 
member or two rotating members in order to substantially reduce the 
friction therebetween. Such a roller bearing generally comprises an inner 
ring and an outer ring, the inner ring being fixedly secured to a rotating 
shaft. Situated between the inner ring and outer ring are a plurality of 
cylindrical rollers. The rollers are generally held in spaced apart 
relationship by a cage, separator or retainer. As the shaft rotates, the 
inner ring rotates with respect to the outer ring, with the cage and 
rollers also rotating. As the speed of the shaft increases, the friction 
generated by the relative motion between the cage, rollers and rings 
increases. 
Generally, roller bearing reliability has kept up with the state-of-the-art 
primarily through the tightening of manufacturing tolerances thereby 
resulting in substantially increased manufacturing costs. As higher speeds 
and more severe loading and alignment conditions arise the manufacturing 
limits of roller bearings are being reached. 
Experience has shown us that roller instability (eccentric and wear) can 
occur in bearings at speeds as low as 1 million DN (DN=bearing bore in 
mm.times.shaft RPM). At speeds greater than 1 million DN continuous 
bearing operation requires uniform oil distribution through the bearing in 
order to reduce wear. The above problems have created unreliability in the 
use of roller bearings. Therefore, there exists a need to not only provide 
a roller bearing which is cost efficient but is also capable of overcoming 
roller instability problems as well as effectively providing uniform 
lubrication to the moving parts of the bearing. 
SUMMARY OF THE INVENTION 
The instant invention overcomes the problems encountered in the past by 
improving the reliability of the cylindrical roller bearing in a cost 
conscious manner by utilizing a separable three piece inner ring structure 
in combination with a novel lubricant distribution system. 
The present invention is in the form of a roller bearing made up of an 
outer ring, an inner ring of three separable elements (two guide rails or 
shoulders and a raceway) which is secured to a rotatable shaft, a 
plurality of cylindrical rollers interposed between the inner and outer 
rings and a cage encompassing the rollers. As a result of the construction 
of the roller bearing of this invention, the cage may be manufactured with 
much greater flexibility since the inner ring can be separated therefrom. 
In addition, the guide rails do not have to be made of the same hardness 
as the inner raceway thereby resulting in lower machining costs. 
Furthermore, as part of this invention, the guide rails incorporate therein 
a unique lubricant distribution system. The lubricant distribution system 
includes a plurality of radial slots within the guide rails which are 
interconnected to a circular-shaped or annular channel juxtaposed to the 
rollers. The channel terminates in a weir having a flat or rounded lip and 
which is concentric with the bore of the guide rails. A slight taper is 
applied to the face of the weir which allows for a buildup of pressure at 
the journal face. Lubrication for the roller bearing may be provided by 
means of oil jets which target lubricant towards the radial slots. Even 
distribution of the lubricant is maintained by centrifugal force acting 
thereon. 
Utilization of a three piece inner ring minimizes the effect of roller 
instability, reduces element end wear and increases the warning time of an 
imminent bearing problem before the bearing loses its centering 
capability. In addition, by utilizing separable guide rails, the bearings 
can be designed with guide rails encompassing as much as 60% of the roller 
diameter. This arrangement allows sufficient room for designing the weir 
and damping characteristics while improving the durability of the bearing. 
More specifically, under conditions of incipient failure such as spalling 
or element instability, wear and possibly vibrations will occur prior to 
catastrophic failure. The bearings high guide rails which contain the 
rollers offer more time before the cage is fractured and/or eventual loss 
of shaft centering occurs thereby substantially improving the safety of 
the bearing while being extremely cost effective. 
An alternate embodiment of this invention modifies the method of 
introducing lubricant into the lubrication system incorporated within the 
guide rails. In this embodiment, lubricant from an orifice is jetted at 
the shaft which in turn reflects the lubricant into a plurality of 
reservoirs. Lubricant from these reservoirs is transferred into the radial 
slots in the guide rails for appropriate distribution. 
It is therefore an object of this invention to provide a roller bearing 
which substantially improves overall bearing reliability. 
It is another object of this invention to provide a roller bearing which 
overcomes the problems of roller instability and roller wear. 
It is still another object of this invention to provide a roller bearing 
which substantially eliminates the effect of end clearance on roller skew 
angle. 
It is a further object of this invention to provide a roller bearing which 
substantially eliminates the problem of guide rail runout. 
It is still a further object of this invention to provide a roller bearing 
which substantially improves lubrication of the bearing. 
It is still another object of this invention to provide a roller bearing 
which is economical to produce and which utilizes conventional, currently 
available components that lend themselves to standard mass producing 
manufacturing techniques. 
For a better understanding of the present invention, together with other 
and further objects thereof, reference is made to the following 
description taken in conjunction with the accompanying drawing and its 
scope will be pointed out in the appended claims.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Reference is now made to FIG. 1 of the drawing which illustrates in a 
cross-sectional view the roller bearing 10 of this invention. Roller 
bearing 10 is made up of a annular outer ring 12, an inner ring 14 and a 
plurality of rollers 16 held in place by a cage structure 18. Outer ring 
12 may be either stationary or rotatable but is illustrated in FIG. 1 of 
the drawing as being fixedly secured to a housing 21 or the like. Inner 
ring 14 is made up of three separate elements, the details of which are 
set forth hereinbelow. 
Ring 14 is also of an annular configuration and is secured upon a rotatable 
shaft 22 so as to be rotatable therewith. Inner ring 14 is preferably 
press fit upon shaft 22 and held in place by any suitable retainer element 
24. Interposed between the inner ring 14 and outer ring 12 are the 
plurality of spaced-apart, cylindrical rollers 16 (two of which being 
shown in FIG. 1 of the drawing). Rollers 16 are held in spaced-apart 
relation by cage structure 18 which fits upon the plurality of rollers 16 
in a conventional manner. 
As part of this invention inner ring 14 is made up of three separable 
elements; a pair of guide rails 26 and 28 and an inner raceway 30. Since 
guide rails 26 and 28 are separable, it is possible to design roller 
bearing 10 such that guide rails 26 and 28 encompass as much as 60% of the 
roller diameter, D. In addition rollers 16 are fabricated such that their 
length, L, to roller diameter, D, ratio is approximately 0.87. Such a 
relationship minimizes any gyro induced guide rail forces. 
Under conditions of incipient failure of bearing 10 such as spalling or 
element instability, wear and possibly vibration will occur prior to 
catastrophic failure. The high guide rails 26 and 28 which contain rollers 
16 therefore offer substantially more time before the fracture of cage 18 
and/or eventual loss of shaft centering occurs. Furthermore, since inner 
ring 14 is made of separable elements, cage 18 can be manufactured of a 
material having greater flexibility than the other elements of the bearing 
10. Further, guide rails 26 and 28 do not have to be made of the same 
material and hardness as inner raceway 30 thereby resulting in lower 
machining costs during the manufacture of bearing 10 of this invention. 
Forming another essential part of this invention is the novel lubricant 
distribution system 32 of bearing 10. In this invention lubrication system 
32 is formed as part of each of the guide rails 26 and 28. The lubrication 
system 32 is made up of identical structure in each guide rail 26 and 28 
and, therefore, for purposes of ease of understanding of the lubrication 
system 32 of this invention the following description will have identical 
elements in each guide rail 26 and 28 being identified with the same 
reference numerals. 
As illustrated in FIGS. 1 and 2 of the drawing, each guide rail 26 and 28 
has located therein a plurality of radial slots 34 (one of which being 
shown clearly in FIG. 2 of the drawing) interconnected with an annular 
channel 36 formed within each guide rail 26 and 28 concentric with the 
bore of each guide rail 26 and 28, respectively. Channel 36 terminates in 
a weir 38 having a flat or rounded lip 39 and which is also formed 
concentric with the bore of its respective guide rail 26 or 28. A slight 
tapered portion 40 is formed adjacent lip 39 of weir 38. 
Any suitable lubricant such as oil is directed into the radial slots 34 by 
way of a plurality of radial holes 50 shown in FIG. 1 of the drawing 
located in shaft 22. Holes 50 are aligned with a plurality of lubricating 
jets 52 situated within the center of shaft 22. The targeting of the oil 
jets 52 to avoid splash depends upon the rotation speed of shaft 22. As 
the lubricant enters the guide rail radial slots 34, even distribution 
(360.degree. within the channel 36) is maintained by centrifugal force on 
the lubricant. 
Even distribution of the lubricant over lip 39 of weir 38 is obtained by 
the concentricity of the lip with the bore of the guide rails 26 and 28. 
The tapered portion 40 adjacent lip 39 of weir 38 allows for a buildup of 
pressure to take place at the face 42 of each guide rail 26 or 28. The 
pressure buildup is illustrated by arrows 44 in FIG. 2 of the drawing. 
FIG. 3 of the drawing illustrates how the pressure indicated by arrows 46 
increases as the leading edge of roller 16 is pressed against guide rail 
26. As this action takes place the opposite side of roller 16 drops in 
pressure as indicated by arrows 48 since the gap between roller 16 and 
guide rail 28 is increased. 
Reference is now made to FIG. 4 of the drawing which shows an alternate 
embodiment of this invention in the form of roller bearing 60. In this 
embodiment of the invention, since the majority of the elements of roller 
bearing 60 are identical to those of roller bearing 10 illustrated in FIG. 
1 of the drawing, identical numerals will be utilized to designate the 
same elements in FIGS. 1 and 4 of the drawing. 
The major difference between roller bearing 60 and roller bearing 10 is the 
manner in which the lubricant is introduced into the radial slots 34. In 
the embodiment of roller bearing 60 illustrated in FIG. 4 of the drawing, 
lubricant in the form of oil, for example, is provided from a supply 62 
which terminates in an orifice 64 thereby jetting the oil lubricant 
against the side of shaft 22. Shaft 22 in turn reflects the lubricant into 
a reservoir 66 formed within a retaining nut 68. A second reservoir 70 is 
situated within nut 68 adjacent reservoir 66 and is interconnected with 
reservoir 66 by a plurality of longitudinal or axially extending grooves 
72. Reservoir 70 terminates in a weir 74 over which the lubricant spills 
in a manner described below. 
As clearly depicted in FIG. 4 of the drawing, it should be realized that 
the entrance or inlet 75 of reservoir 66 is of a smaller diameter 
(illustrated as radius R.sub.1) than the diameter (illustrated as radius 
R.sub.2) of groove 72 while the diameter of groove 72 is smaller in turn 
than the diameter (illustrated by radius R.sub.3) of the weir 74. This 
leads to a stepped up configuration which introduces lubricant into a 
plurality of axially extending slots or grooves 76 situated within a 
spacer 78. Spacer 78 is interposed between guide rails 26 and 28, raceway 
30 retainer nut 68 and shaft 22. It therefore follows that the diameter 
(illustrated as radius R.sub.4) of groove 76 is larger than the diameter 
of weir 74. 
A plurality of radially extending holes 80 are formed within spacer 78 
thereby interconnecting grooves 76 with the radially extending slots 34 in 
guide rails 26 and 28. Thereafter, actual lubrication of rollers 16 can be 
accomplished in a similar manner to that depicted with respect to roller 
bearing 10 and illustrated in FIGS. 1-3 of the drawing. A lubrication 
system as depicted with bearing 60 of FIG. 4 may be preferable to that 
illustrated with respect to bearing 10 in certain instances, for example, 
in which shaft 22 cannot accommodate a centrally located lubricating 
arrangement. 
With the use of this invention, as depicted with either embodiment, roller 
skew angle and end clearance tolerances are greatly reduced. Furthermore, 
an even distribution of lubricant and coolant by a centrifugally fed weir 
built into the guide rails 26 and 28 of separable inner ring 14 can be 
obtained. 
Although this invention has been described with reference to particular 
embodiments, it will be understood that this invention is also capable of 
further and other embodiments within the spirit and scope of the appended 
claims.