Unitized single row tapered roller bearing

A single row tapered roller bearing capable of taking radial loading as well as thrust loading in both axial directions has a cone provided with an integral thrust rib at the small diameter end of its raceway, a cup surrounding the cone, tapered rollers between the raceways of the cup and cone, a separate rib ring at the large diameter end of the cup raceway, and a cage for maintaining correct spacing between the rollers in the circumferential direction. The cage at one end has an outwardly directed lip which is too large to fit through the rib ring and at its other end has outwardly directed tabs which are too large to fit through the cup without deflecting. In effect, the cup and rib ring are captured between the lip and tabs on the cage, and since the rib ring and cup cannot separate, the rollers and cone remain in place, providing a bearing which is unitized sufficiently for normal handling.

BACKGROUND OF THE INVENTION 
This invention relates in general to bearings and more particularly to a 
unitized bearing capable of taking radial loading as well as thrust 
loading in both axial directions. 
While most single row tapered roller bearings are capable of accommodating 
thrust loading in only one axial direction, some are capable of taking the 
thrust loading in both axial directions. The latter are widely used in the 
rear axles of automobiles. The typical bearing having this capability, 
differs from the conventional single row tapered roller bearings in that 
it has a thrust rib at the large diameter end of the cup raceway and 
another thrust rib at the small diameter end of the cone raceway. Thus, 
conventional thrust loading is accommodated in the usual manner, that is 
the thrust load is transferred to the rollers at the raceways. However, 
when the thrust load is applied in the opposite direction, the rollers are 
compressed between the two ribs so that thrust load is transferred to the 
rollers through the ribs. 
The thrust rib at the large diameter end of the cup is actually a separate 
ring which is detached during the initial assembly of the bearing, for 
otherwise it would be impossible to fit the conventional number of rollers 
between the cup and cone. Only after the rib ring, the cage, the rollers 
and the cone are assembled together is the cup fitted against the rib 
ring, and the two are usually clamped together in the housing in which the 
bearing is installed. 
To prevent the bearing from falling apart during handling and installation 
into a bearing housing, it is desirable to retain the rib ring against the 
cup, even if only on a temporary basis. U.S. Pat. No. 3,420,589 of W. F. 
Green et. al. shows several ways of achieving this end. Perhaps the most 
popular method is to bond the rib ring to the cup with an adhesive. While 
this seems to be a relatively simple procedure, it is actually not since 
it necessitates a considerable amount of precision machining and other 
preparation. In particular, the opposing faces of the cup and rib ring 
must be perfectly flat and square which requires expensive machining 
operations. Also, to assure good adhesion, these faces must be 
ultrasonically cleaned. Then the adhesive must be applied, and this is 
usually a manual operation. Finally, the bearing must be placed in an oven 
to cure the adhesive. Aside from the foregoing, the inside diameter of the 
rib ring must be tapered to provide clearance for the metal cage. This is 
achieved during the initial machining of the rib ring, but is a costly 
operation since it involves machining a reverse taper, a procedure 
commonly referred to as back boring. 
SUMMARY OF THE INVENTION 
One of the principal objects of the present invention is to provide a 
single row bearing which has the capability of taking thrust loading in 
both axial directions and is unitized for handling. Another object is to 
provide a bearing of the type stated which is unitized by its cage. A 
further object is to provide a bearing, the cage of which may be injection 
molded from plastic. An additional object is to provide a bearing of the 
type stated which is easily and inexpensively assembled. Still another 
object is to provide a bearing of the type stated, the rib ring of which 
may be manufactured to more liberal tolerances on certain surface areas. 
These and other objects and advantages will become apparent hereinafter. 
The present invention is embodied in a single row bearing having an inner 
race that is larger at its one end than at its other and is provided with 
a thrust rib at the small diameter end of its raceway, an outer race 
surrounding the inner race, rolling elements between the raceways of the 
inner and outer races, a rib ring at the large diameter end of the raceway 
on the outer race, and a cage configured to maintain correct spacing 
between the rollers. The cage has means for preventing separation of the 
outer race and the rib ring so that the bearing is unitized. The invention 
also consists in the parts and in the arrangements and combinations of 
parts hereinafter described and claimed.

DETAILED DESCRIPTION 
Referring now to be drawings (FIG. 1), A designates a single row bearing 
which is capable of taking radial loading as well as thrust loading in 
both axial directions, and this bearing is normally installed in a housing 
H for supporting a shaft S in the housing H. The bearing A is unitized at 
assembly to the extent that it will remain together during normal handling 
and while being installed in the housing H. However, the unification which 
is achieved at initial assembly is not strong enough to withstand normal 
operating loads. Consequently, the housing H is configured to clamp across 
the bearing A and hold it together under operating conditions. 
The bearing A has five basic components, namely a cone 2, a cup 4, a rib 
ring 6, a complement of tapered rollers 8, and a cage 10 (FIG. 1). The 
cone 2 fits over the shaft S, while the cup 4 fits into the housing H 
through which the shaft S extends. The cup 4 surrounds the cone 2 and 
interposed between the two are the tapered rollers 8 which enable the cone 
2 to rotate freely within the cup 4 with the axis of rotation being the 
axis X of the bearing A. The rib ring 6 fits against the end of the cup 4 
and is located opposite the large diameter ends of the rollers 8 to 
prevent the rollers 8 from being expelled from the space between the cone 
2 and cup 4. The cage 10 maintains the proper spacing between adjacent 
rollers 8 and prevents separation of the rib ring 6 from the end of the 
cup 4, at least when the bearing A is outside of its housing H, and this 
confines the rollers 8, the cage 10, and the cone 2 within the cup 4. In 
other words, the cage 10 unitizes the bearing A for handling purposes. 
The cone 2 (FIG. 2), which is the inner race of the bearing A, has a center 
bore 12 through which the shaft S extends and at its ends has squared off 
front and back faces 14 and 16. In addition, it has a tapered raceway 18 
which is presented outwardly toward the cup 4 and the taper of this 
surface is such that the apex of the cone defined by it is located along 
the axis X of rotation for the bearing A. The raceway 18 leads up to the 
back face 16, while the small diameter end of the raceway 18 is located 
adjacent to a thrust rib 20 which projects outwardly from raceway 18. The 
thrust rib 20 constitutes an integral part of the cone 2, and has the cone 
front face 14 along its one end and an abutment face 22 at its other end. 
The abutment face 22 is, therefore, at the small diameter end of the 
raceway 18. 
The cup 4 (FIG. 2), which is the outer race of the bearing A, has a 
cylindrical external surface 24 which faces outwardly and is sized to fit 
into the housing H. The inwardly presented surface of the cup 4 is tapered 
to form a tapered raceway 26 which is located opposite the tapered raceway 
18 of the cone 2. Both the cylindrical surface 24 and the tapered raceway 
26 extend between front and back faces 28 and 30 which are squared off 
with respect to the axis of rotation X. 
The rollers 8 are frustonconical in shape and have their tapered side 
surfaces located against tapered raceways 18 and 26 of the cone 2 and cup 
4, respectively, while the small diameter ends of these rollers 8 are 
located adjacent to the abutment face 22. When the bearing A is subjected 
to radial loading, the generally radial force upon being transferred 
through the rollers 8 acquires an axial component which urges the rollers 
8 away from the thrust rib 20 and tends to expel them from the space 
between the cone 2 and cup 4. The rib ring 6 prevents expulsion. 
The rib ring 6 fits against the front face 28 of the cup 4 (FIG. 2) and has 
an outside diameter which equals or is slightly less than the diameter of 
the cylindrical outside surface 24 on the cup 4. The two end faces of the 
ring 6 are squared off with respect to the axis X so that one abuts 
facewise against the front face 28 of the cup 4, while the other is 
exposed at the end of the bearing A to receive forces applied to the 
bearing A. The latter or exposed end face merges into a ring bore 31 at a 
chamfer 32. The ring 6 may be formed with an axially directed lip or rib 
34 through which the ring bore 31 extends, and the rib 34 projects a short 
distance into the interior of the cup 4 along the cup raceway 26. The rib 
34 terminates at an abutment face 36 which is presented toward the 
abutment face 22 on the thrust rib 20 and bears against the large diameter 
ends of the rollers 8. Alternately, the rib ring 6 may be formed without 
the rib 34, in which case the abutment face 36 aligns with the cup front 
face 28. In either arrangement, the expulsion forces on the rollers 8 are 
resisted at the abutment face 36. Furthermore, when a thrust load is 
applied to the bearing A in the direction which tends to unseat the 
rollers 8 from the raceways 18 and 26, that is in the direction which 
causes the ribs 20 and 34 to move together, the abutment faces 22 and 36 
of the ribs 20 and 34, respectively, bear against the ends of the rollers 
8 so that the rollers 8 are compressed between the ribs 20 and 34. 
Finally, the rib ring 6, when held against the front face 28 of the cup 4, 
serves to unitize the bearing A, for it prevents the rollers 8 from 
leaving the space between the cone 2 and cup 4 and when the rollers 8 are 
in place, the cone 2 cannot be withdrawn from the cup 4. 
The cage 10 (FIG. 3) is preferably injection molded from a high strength 
plastic, although it may also be stamped from metal, as is the 
conventional practice, die cast from aluminum or some other metal, or 
formed by powdered metal techniques. The cage 10 includes large and small 
diameter rings 40 and 42, which are located in the annular space between 
the cone 2 and cup 4, with the former lying immediately beyond the large 
diameter ends of the rollers 8 and the latter being immediately beyond the 
small diameter ends. The two rings 40 and 42 are connected by bridges 44, 
thus forming a plurality of circumferentially spaced pockets 46 in the 
cage 10. Each pocket 46 receives a different roller 8 so that the bridges 
44 are disposed between the tapered side faces of adjacent rollers 8 and 
maintain the proper spacing between the rollers 8. The diameters of the 
two rings 40 and 42 are such that the major portions of the bridges 44 are 
held outwardly slightly beyond the cone formed by the center lines of the 
rollers 8 (FIGS. 4 and 5). Moreover, the side faces of the bridges 44 are 
beveled slightly to conform to the contour of the rollers 8 which are 
against them. Consequently, the bridges 44 are wider at their outside 
surfaces than at their inside surfaces. The bevels on the side faces of 
the bridges 44 maintain the entire cage 10 in an overcenter position with 
respect to the rollers, that is, it enables the cage 10 to more or less 
float on the complement of rollers 8 and thereby prevents any one portion 
of the cage 10 from moving inwardly into the imaginary cone defined by the 
center lines of the rollers 8. 
The large ring 40 of the cage 10 has a generally cylindrical outwardly 
presented surface 48 (FIG. 2) which lies slightly inwardly from the 
surface of the ring bore 31 on the rib ring 6. The cylindrical surface 48 
leads up to a beveled lip 50 (FIGS. 2 and 3) which lies directly inwardly 
from the chamfer 32 on the rib ring 6. Indeed, the lip 50 projects 
outwardly into the chamfer 32 and hence is disposed beyond the ring bore 
31. As a result, the lip 50 prevents withdrawal of the rib ring 6 from the 
cup 4. Directly beyond each brdige 44, the thickness of the large ring 40 
corresponds to the thickness of the bridge 40, so that the bridges 44 
appear to extend axially through the large ring 40 (FIG. 3). However, to 
the sides of the bridges 44, that is in the area immediately beyond the 
pockets 46, the large ring 40 is provided with inwardly opening reliefs 52 
where the thickness of the ring 40 is substantially reduced. As a 
consequence, the end of each pocket 46 is closed by a relatively thin band 
54, the outside surface of which constitutes part of the cylindrical 
surface 48 (FIG. 2) that leads up to the lip 50. 
The samll ring 42 has a generally uniform thickness and lies directly 
outwardly from the thrust rib 20 of the cone 2. At equal circumferential 
intervals, it is provided with retaining tabs 56 (FIGS. 2 and 3) which 
project outwardly and terminate opposite the cup back face 30, thereby 
preventing the cup 4 from backing away from the rollers 8. The tabs 56 
extend only slightly beyond the inner margin of the back face 30 so that 
sufficient surface area remains unobscured to provide the cup 4 with an 
adequate backing for its back face 30. 
The beveled lip 50 at the large end of cage 10 and the retaining tabs 56 at 
the small end serve to unitize the bearing by virtue of the fact that they 
project outwardly and interfere with the rib ring 6 and cup 4, 
respectively (FIG. 2). This prevents the cup 4 and rib ring 6 from 
separating. Consequently, the rollers 8 and cage 10 as well as the cone 2 
are all captured in the unified cup 4 and rib ring 6. In particular, the 
cone 2 prevents the rollers 8 from moving radially inwardly, while the cup 
4 prevents them from moving radially outwardly. The cone rib 20 and the 
taper of the cone and cup raceways 18 and 26 prevents the rollers 8 from 
being expelled in the opposite axial direction. The taper of the cone 
raceway 18 and the cone thrust rib 20 confine the cone 2 such that it 
cannot move axially in either direction with respect to the cup 4, other 
than for a few thousandths of an inch required for adequate clearance in 
the bearing A. 
The cage 10 is preferably formed by an injection molding process which 
utilizes a mold having a center core and a shell composed of two C-shaped 
mold halves which, when closed, surround the core so that a mold cavity 
exists between the core and the shell. The mold is opened by withdrawing 
the C-shaped halves from one another and from the core, the movement being 
away from the axial center line of the core. Once the plastic injected 
into the mold cavity solidifies, the C-shaped halves are withdrawn from 
the core, leaving the cage 10 surrounding the core. Then the cage 10 is 
then pulled off of the mold core, it being withdrawn in the axial 
direction, large end first. 
To assemble the bearing A, the rib ring 6 is set into a fixture F (FIG. 6) 
with its axial rib 34 projecting downwardly. Next, the small end of the 
cage 10 is inserted into the rib ring 6, and the cage 10 is advanced until 
its small ring 42 rests against the bottom of the fixture F in which case 
the beveled lip 50 on the large ring 40 will lie in the chamfer 32 of the 
rib ring 10. In this regard, every part of the cage, except the lip 50 is 
smaller in diameter than the bore 48 of the rib ring 6. Once the cage 10 
is in place, the rollers 8 are fitted into the cage 10 by forcing them 
outwardly into the pockets 46 from the interior of the cage 10. The 
insertion force applied to the rollers 8 is sufficient to enable the 
bridges 44 to grip the rollers 8 and retain them in place. Next, the cone 
2 is inserted into the rib ring 6 and pushed through the rollers 8 with 
its thrust rib 20 leading (FIG. 6). As the cone 2 advances, the thrust rib 
20 spreads the rollers 8 outwardly beyond the position they normally 
occupy in the cage 10 and this spreading is accommodated by deflection in 
the bridges 44 for the cage 10. To facilitate advancement of the cone 2 
through the rollers 8, the outwardly present surface of the cone thrust 
rib 20 may be tapered. Once the thrust rib 20 passes beyond the small 
diameter ends of the rollers 8, the bridges 44 force the rollers 8 
inwardly toward the cone raceway 18. 
The assembly which is so formed is then removed from the fixture F. Since 
the cage 10 is disposed in an overcenter position with respect to the 
complement of rollers 8 and the side faces of the cage bridges 44 are 
beveled to conform to the contour of the rollers 8, the rollers 8 remain 
around the cone 2. The rib ring 6 likewise remains in place since it is 
captured between the large diameter ends of the rollers 8 and the beveled 
lip 50 on the cage 10. Finally, the cup 4 is installed by placing the 
large end of its raceway 26 around the retaining tabs 56 on the small ring 
42 of the cage 10 and then advancing the cup 4 toward the rib ring 6 (FIG. 
7). As the cup advances, its raceway 26 bends the tabs 56 inwardly toward 
the rollers 8, but once the cup back face 30 passes tabs 56, the tabs 56 
snap outwardly and prevent withdrawl of the cup 4. In effect, the cup 4 
and rib ring 6 are captured between beveled lip 50 and the tabs 56 on the 
cage 10, and this unitizes the entire bearing A. The cage 10 possesses 
sufficient strength to resist the tendency of the cup 4 and rib ring 6 to 
separate during normal handling operations, so the bearing does not fall 
apart and become merely a multitude of individual pieces. 
In use, the bearing A is installed in a housing H such that cup 4 and rib 
ring 6 are physically clamped together by the housing H and the cup 4 
cannot move in either axial direction with respect to the housing H. The 
shaft S, which fits through the housing H and the cone 2 of the bearing A, 
has shoulders opposite each end face 14 and 16 of the cone 2 so that it is 
confined in both axial directions with respect to the cone 2. The bearing 
A, of course, takes thrust loading in both axial directions. When the 
thrust load is exerted in the direction which seats the rollers 8 against 
the raceways 18 and 26, the load is applied to the rollers at the raceways 
18 and 26 and is transmitted generally transversely through the rollers 8. 
When exerted in the opposite axial direction, the thrust load is applied 
to the rollers 8 at the abutment faces 22 and 36 on the ribs 20 and 34, 
respectively, and is transmitted generally axially through the rollers 8. 
The rib ring 6 further prevents the rollers 8 from being expelled from the 
bearing A under radial loading, and is held against the cup 4 by the 
physical clamping achieved in the housing H in which the bearing A is 
installed (FIG. 1), not by the beveled lip 50 and retaining tabs 56 on the 
cage 10. 
To render the bridges 44 more flexible so that they will yield somewhat 
more easily during assembly, that is, when the cone 2 is pushed through 
the rollers 8, the bridges 44 may be provided with outwardly opening 
grooves 60 which have their greatest depth at the small ring 42 (FIGS. 8 
and 9). The opposite ends of the grooves 60 flare outwardly and merge into 
the cylindrical surface 48. Also, the retaining tabs 56 may be provided on 
their sides facing the pockets 46 with undercuts 62 (FIG. 8) which enable 
them to flex more easily as the cup 4 is forced over the assembled cone 2, 
rib ring 6, rollers 8, and cage 10. A cage 10 having the grooves 60 and 
undercuts 62 would not lend itself to production on a mold having two 
C-shaped mold halves. The core of the mold would be the same as the 
previous mold, but the shell which surrounds the core would be withdrawn 
from the core in the axial direction. 
Since the rib ring 6 is not adhered to the front face 28 of the cup 4, no 
need exists to prepare the front face 28 and the opposite surface on the 
rib ring 6 for an adhesive. Likewise, the steps of applying the adhesive 
and curing it in an oven are eliminated. Also, the inner surface of the 
rib ring 6, that is, the ring bore 31, is cylindrical, and not tapered as 
on conventional unitized bearings, and consequently, no need exists for 
back boring a reverse taper. 
This invention is intended to cover all changes and modifications of the 
example of the invention herein chosen for purposes of the disclosure 
which do not constitute departures from the spirit and scope of the 
invention.