The background information herein below relates to the present disclosure but is not
necessarily prior art.
5 A tapered roller bearing is a rolling element bearing that is used for supporting loads
which have axial as well as radial components. A typical tapered roller bearing has a
cone-shaped outer raceway and a cone-shaped inner raceway, and a plurality of
tapered rollers is placed between the cone-shaped surfaces. The outer raceway is
defined on the outer ring, termed as a ‘cup’, and the inner raceway is defined on the
10 inner ring, termed as a ‘cone’. A cage holds the tapered rollers between the cup and
the cone and prevents the rollers from slipping out.
A characteristic of a tapered roller bearing is, along any axial section of a tapered
roller bearing, the axes of the tapered roller and the projections of the conical surfaces
of the cup and the cone meet at a common ‘apex’ point on the central axis of the
15 tapered roller bearing. The principle behind this characteristic is that when conical
surfaces of cones that meet at a point are placed against each other, pure rolling
motion can be imparted between the cones without any slippage.
Fitting of a tapered roller bearing involves consideration of axial and radial
clearances and the variations in the clearances due to press-fitting, temperature
20 changes, vibrations and so on. In general, for any type of a bearing, press-fitting of
either the inner race or the outer race reduces the radial clearance within the bearing.
This reduction in clearance has been compensated for at the time of bearing
manufacture. Therefore, it is essential that the recommended fitting practices be
adhered to assure that the bearing will operate with the proper installed clearance.
3
The fit of a bearing ring on which a rotating load is applied should generally be an
interference fit. When the cone of a tapered roller bearing is force -fitted, the tapering
cross-section of the cup or the cone results in differential deformation of the cup or
the cone. The thinner portion, due to comparatively less material along the direction
5 of the compressive force resisting the deformation, undergoes more deformation than
the thicker portion. In case of the cone, due to such an uneven increase in the cone
bore diameter, the cone angle changes. As a result, the cone and the tapered rollers no
longer define an apex point as described above. In this condition, the tapered roller
bearing has no true rolling. Sliding of rollers starts. Rollers tend to tilt, due to which
10 edge rolling can also start. Friction increases, which causes higher heat generation.
Therefore, there is felt a need of a tapered roller bearing which alleviates the
aforementioned drawbacks of prior art.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein
15 satisfies, are as follows:
A primary object of the present disclosure is to provide a tapered roller bearing that
undergoes pure rolling after installation.
Another object of the present disclosure is to provide a tapered roller bearing that has
an apex point after installation.
20 Another object of the present disclosure is to provide a tapered roller bearing that is
free from detrimental phenomena such as tilting of rollers or edge rolling and
resultant increase in frictional heat generation.
Other objects and advantages of the present disclosure will be more apparent from the
following description, which is not intended to limit the scope of the present
25 disclosure.
4
SUMMARY
The present disclosure envisages a tapered roller bearing kit. The tapered roller
bearing kit comprises a cup, a cone and a roller assembly consisting of a cage and
tapered rollers. The cup has a conical radially inner surface defining the outer
5 raceway and a radially outer surface configured to be force-fitted within a housing.
The cone has a conical radially outer surface defining the inner raceway and a
radially inner surface configured to be force-fitted over a shaft.
The radially outer surface of the cup is non-cylindrical. The radially inner surface of
the cone is non-cylindrical.
10 The diameters of the radially inner surface of the cone are defined to compensate for
deformation due to a predetermined interference fit of installation of the cone, and to
change inclination of the projection of the outer raceway, the projection of the inner
raceway and the axes of the tapered rollers, causing them to intersect at a single point
on the central axis of the tapered roller bearing, when the cone is fitted over the shaft.
15 Preferably, the diameter of radially inner surface of the cone before installation
increases towards the smaller cross-section of the cone. In an embodiment, the
difference in diameters of radially inner surface of the cone before installation at its
smaller cross-section and its larger cross-section depends on interference and
geometry of the cone.
20 In another embodiment, the angle of tilt of the radially inner surface of the cone
relative to the axis of the bearing before installation depends on loading and boundary
conditions.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
A tapered roller bearing kit, of the present disclosure, will now be described with the
25 help of the accompanying drawing, in which:
5
Figure 1 illustrates a tapered roller bearing, of prior art, as available in the kit, before
installation;
Figures 2a and 2b illustrate a cone of prior art and a corresponding shaft, before and
after installation, respectively;
5 Figure 3 illustrates projection lines of a tapered roller bearing of prior art, after
installation;
Figure 4a and 4b illustrate projection lines of a tapered roller bearing of the present
disclosure, before installation (i.e., , as available in the kit) and after installation,
respectively; and
10 Figures 5a and 5b illustrate a cone of the present disclosure and a corresponding
shaft, before installation (i.e., as available in the kit) and after installation,
respectively.
LIST OF REFERENCE NUMERALS
100’ tapered roller bearing of prior art
15 10’ cup of prior art
11’ outer raceway of prior art
12’ projection of outer raceway of prior art
20’ cone of prior art
21’ inner raceway of prior art
20 22’ projection of inner raceway of prior art
24’ radially inner surface of the cone of prior art
30’ tapered roller of prior art
6
32’ axis of a tapered roller of prior art
40’ central axis of tapered roller bearing of prior art
100 tapered roller bearing of the present disclosure
10 cup of the present disclosure
5 11 outer raceway of the present disclosure
12 projection of outer raceway of the present disclosure
20 cone of the present disclosure
21 inner raceway of the present disclosure
22 projection of inner raceway of the cone of the present disclosure
10 24 radially inner surface of the cone of the present disclosure
30 tapered roller of the present disclosure
32 axis of a tapered roller of the present disclosure
40 central axis of the present disclosure
50 shaft
15 60 housing
A apex point
DETAILED DESCRIPTION
Embodiments, of the present disclosure, will now be described with reference to the
accompanying drawing.
7
Embodiments are provided so as to thoroughly and fully convey the scope of the
present disclosure to the person skilled in the art. Numerous details are set forth,
relating to specific components, and methods, to provide a complete understanding of
embodiments of the present disclosure. It will be apparent to the person skilled in the
5 art that the details provided in the embodiments should not be construed to limit the
scope of the present disclosure. In some embodiments, well-known processes, wellknown apparatus structures, and well-known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining
a particular embodiment and such terminology shall not be considered to limit the
10 scope of the present disclosure. As used in the present disclosure, the forms “a”, “an”
and “the” may be intended to include the plural forms as well, unless the context
clearly suggests otherwise. The terms “comprises”, “comprising”, “including” and
“having” are open-ended transitional phrases and therefore specify the presence of
stated features, elements, modules, units and/or components, but do not forbid the
15 presence or addition of one or more other features, elements, components, and/or
groups thereof.
When an element is referred to as being “mounted on”, “engaged to”, “attached to”,
“connected to” or “coupled to” another element, it may be directly on, engaged,
attached, connected or coupled to the other element. As used herein, the term
20 “and/or” includes any and all combinations of one or more of the associated listed
elements.
Terms such as “inner”, “outer”, “beneath”, “below”, “lower”, “above”, “upper” and
the like, may be used in the present disclosure to describe relationships between
different elements as depicted from the figures.
25 Figure 1 shows the point of intersection of the projection 12’ of the conical surface of
the cup 10’, i.e., the outer raceway 11’, the projection 22’ of the conical surface of the
cone 20’, i.e., the inner raceway 21’, and the axes 32’ of the tapered rollers 30’ at the
8
central axis 40’ of the kit of a tapered roller bearing 100’ of prior art, before the shaft
50 is fitted into the bore of the cone 20’ with interference fit and the cup 10’ is fitted
into the housing 60 with interference fit.
The deformation occurring in the cone 20’ of a tapered roller bearing 100’ due to
5 interference fit is non-uniform due to non-uniform thickness along the axial direction
thereof, as shown in Figure 2b and Figure 3b, respectively. The bore of the cone
20’, that is straight before the fitting, as shown in Figure 2a, tilts after installation, as
shown in Figure 2b. As shown in Figure 3a, the cone angle of the cone20’ is θ
before the interference of the shaft 60 and the cone20’, which changes to (θ+δθ) after
10 the interference of the shaft 60 and the cone 20’, as shown in Figure 2a. As a
consequence, as shown in Figure 4, the tapered rolling bearing 100’ loses its
characteristic ‘apex point’ A, i.e., the projection 22’ of conical surface of the cone
20’, i.e., the inner raceway 21’, and the axes 32’ of the tapered rollers 30’ do not
intersect at a single point on the central axis 40’ of the tapered roller bearing 100’.
15 Hence, pure rolling does not happen between the tapered rollers 30’ and the cone 20’.
This is highly detrimental to the performance and the life of the tapered roller bearing
100’.
A kit of a tapered roller bearing 100 in accordance with an embodiment of the present
disclosure, is now described with reference to Figure 4a through Figure 6b.
20 The present disclosure envisages a kit of a tapered roller bearing 100 comprising a
cone 20 having a non-cylindrical radially inner surface 24’ before installation, so as
to not define the ‘apex point’ before the interference fit of the cone 20 with a shaft 50
is done, as shown in Figure 4a. The diameters of the radially inner surface 24 of the
cone 20 before installation, i.e., the surface of the cone 20 that fits on the shaft 50, are
25 defined to compensate for deformation due to a predetermined interference fit of
installation of the cup 10 and the cone 20. After installation, the projection 22 of the
conical surface of the cone 20, i.e., the inner raceway 21, and the axes 32 of the
9
tapered rollers 30 intersect at a single point, i.e., the apex point A, on the central axis
40 of the tapered roller bearing 100. Since the apex point A now exists after
installation, i.e., after the interference fit of the cone 20 with a shaft 50 is done, as
shown in Figure 4b, pure rolling between the rolling surfaces of the tapered roller
5 bearing 100 is ensured. In other words, sliding between the tapered rollers 30 and the
cone 20 does not occur. Moreover, detrimental phenomena such as edge rolling of the
tapered rollers 30 or tilting of rollers 30 do not occur. Friction and thereby heat
generation is minimized.
In an embodiment, the pre-installation diameter of the radially inner surface 24 of the
10 cone 20 increases towards the smaller cross-section of the cone 20. This feature is
derived on the basis of the observation that, for the cone 20, the smaller cross-section
undergoes more deformation than the larger cross-section, for a given uniform
interference fit. Hence, having a larger diameter of the radially outer surface at the
smaller cross-section would compensate for the larger deformation occurring therein.
15 In an embodiment, the pre-installation difference in diameters of radially inner
surface 24’ of the cone 20 at its smaller cross-section and its larger cross-section
depends on interference and geometry of cone, mainly on slope of the cone.
In another embodiment, the angle of tilt of the pre-installation radially inner surface
24 of the cone 20 relative to the central axis 40 of the tapered roller bearing 100
20 depends on loading and boundary conditions.
Experiment 1: Finite element analysis:
Finite element analysis of an axis-symmetric model of a cone of a kit a tapered roller
bearing of the present disclosure was carried out. Properties of bearing steel were
assumed for the cone and the shaft.
10
Interference
between
shaft and
cone
(in µm)
Conventional tapered roller
bearing
Tapered roller bearing of the
present disclosure
deflection
in major
diameter
(in µm)
deflection
in minor
diameter
(in µm)
deflection
in track
from the
ideal
dimension
(in µm)
deflection
in major
diameter
(in µm)
deflection
in minor
diameter
(in µm)
deflection
in track
from the
ideal
dimension
(in µm)
400 284 345 61 284 284 0
300 219 265 46 215 215 0
200 155 172 17 151 151 0
100 73 86 13 72 72 0
Table-1
Inference: The net angular deflection from the ideal angle of the cone, predicted by
the FEA model for the conical surface of the cone, i.e., the inner raceway of the
tapered roller bearing for various interference values is zero. Therefore, it would be
5 ensured that the projection of the conical surface of a cone of this design would
coincide with the axes of the corresponding tapered rollers, as defined in the
aforementioned paragraphs, after the interference fit of the cone would be done.
The foregoing description of the embodiments has been provided for purposes of
illustration and not intended to limit the scope of the present disclosure. Individual
10 components of a particular embodiment are generally not limited to that particular
embodiment, but, are interchangeable. Such variations are not to be regarded as a
11
departure from the present disclosure, and all such modifications are considered to be
within the scope of the present disclosure.
TECHNICAL ADVANCEMENTS
The present disclosure described herein above has several technical advantages
5 including, but not limited to, the realization of a kit of a tapered roller bearing that
has:
 projections of the raceways and of the axes of the tapered rollers meeting at a
common point on the bearing axis after installation of the bearing;
 pure rolling and therefore no sliding;
10  reduced friction;
 reduced heat generation;
 no edge rolling; and
 no tilting of rollers.
The embodiments herein and the various features and advantageous details thereof
15 are explained with reference to the non-limiting embodiments in the following
description. Descriptions of well-known components and processing techniques are
omitted so as to not unnecessarily obscure the embodiments herein. The examples
used herein are intended merely to facilitate an understanding of ways in which the
embodiments herein may be practiced and to further enable those of skill in the art to
20 practice the embodiments herein. Accordingly, the examples should not be construed
as limiting the scope of the embodiments herein.
The foregoing description of the specific embodiments so fully reveal the general
nature of the embodiments herein that others can, by applying current knowledge,
12
readily modify and/or adapt for various applications such specific embodiments
without departing from the generic concept, and, therefore, such adaptations and
modifications should and are intended to be comprehended within the meaning and
range of equivalents of the disclosed embodiments. It is to be understood that the
5 phraseology or terminology employed herein is for the purpose of description and not
of limitation. Therefore, while the embodiments herein have been described in terms
of preferred embodiments, those skilled in the art will recognize that the
embodiments herein can be practiced with modification within the spirit and scope of
the embodiments as described herein.
10 The use of the expression “at least” or “at least one” suggests the use of one or more
elements or ingredients or quantities, as the use may be in the embodiment of the
disclosure to achieve one or more of the desired objects or results.
While considerable emphasis has been placed herein on the components and
component parts of the preferred embodiments, it will be appreciated that many
15 embodiments can be made and that many changes can be made in the preferred
embodiments without departing from the principles of the disclosure. These and other
changes in the preferred embodiment as well as other embodiments of the disclosure
will be apparent to those skilled in the art from the disclosure herein, whereby it is to
be distinctly understood that the foregoing descriptive matter is to be interpreted
20 merely as illustrative of the disclosure and not as a limitation.

WE CLAIM:

1. A kit of a tapered roller bearing (100) including a cup (10), a cone (20) and a
roller assembly consisting of a cage and tapered rollers (30), said cup (10)
having a conical radially inner surface defining the outer raceway (11) and a
5 radially outer surface configured to be force-fitted within a housing (60), said
cone (20) having a conical radially outer surface defining the inner raceway
(21) and a radially inner surface (24) configured to be force-fitted over a shaft
(70), characterized in that said radially inner surface (24) of said cone (20) is
non-cylindrical
10 2. The tapered roller bearing kit (100) as claimed in claim 1, wherein the
diameters of the radially inner surface (24) of said cone (20) are defined to
account for deformation due to a predetermined interference fit of installation
of the cone (20), and to change inclination of, the projection (22) of the inner
raceway (21) and the axes (32) of the tapered rollers (30), causing them to
15 intersect at a single point on the central axis (40) of the tapered roller bearing
(100), the cone (20) is fitted over the shaft (50).
3. The kit of a tapered roller bearing kit (100) as claimed in claim 1, wherein the
diameter of radially inner surface (24) of the cone (20) increases towards the
smaller cross-section of the cone (20).
20 4. The kit of a tapered roller bearing kit (100) as claimed in claim 3, wherein the
difference in diameters of radially inner surface (24) of the cone (20) at its
smaller cross-section and its larger cross-section depends on interference and
geometry of the cone (20).
5. The kit of a tapered roller bearing kit (100) as claimed in claim 4, wherein the
25 difference in diameters of radially inner surface (24) of the cone (20) at its
14
smaller cross-section and its larger cross-section depends on slope of the cone
(20).
6. The kit of a tapered roller bearing kit (100) as claimed in claim 4, wherein the
angle of tilt of the radially inner surface (24) of the cone (20) relative to the
5 axis of the bearing (100) depends on loading and boundary conditions.