U.S. patent application number 12/833439 was filed with the patent office on 2011-02-03 for bearing assembly.
This patent application is currently assigned to AKTIEBOLAGET SKF. Invention is credited to Marcel Gersting, Roland Haas, Elke Huhn, Peter Lemper, Volker Wendt.
Application Number | 20110026865 12/833439 |
Document ID | / |
Family ID | 43307784 |
Filed Date | 2011-02-03 |
United States Patent
Application |
20110026865 |
Kind Code |
A1 |
Haas; Roland ; et
al. |
February 3, 2011 |
Bearing Assembly
Abstract
A bearing assembly includes at least one outer ring and an inner
ring unit having at least two inner rings, each having a central
bore. A supporting element extends through the central bores.
Roller bodies are rotatably disposed between the at least one outer
ring and each of the inner rings. Radially-outer bores extend
through the inner ring unit or the supporting element in the axial
direction and each receives a screw or bolt for affixing the
bearing assembly on a bearing carrier. The radially-outer bores are
spaced from the symmetry axis of the bearing assembly. At least one
lubrication conduit is defined on or in at least one of the inner
rings and is configured to communicate liquid lubricant to the
roller bodies.
Inventors: |
Haas; Roland; (Hofhelm,
DE) ; Huhn; Elke; (Schweinfurt, DE) ;
Gersting; Marcel; (Schweinfurt, DE) ; Wendt;
Volker; (Uchtelhausen, DE) ; Lemper; Peter;
(Hitzacker, DE) |
Correspondence
Address: |
SKF USA Inc.
890 Forty Foot Road, PO Box 352
Lansdale
PA
19446
US
|
Assignee: |
AKTIEBOLAGET SKF
Goteborg
SE
|
Family ID: |
43307784 |
Appl. No.: |
12/833439 |
Filed: |
July 9, 2010 |
Current U.S.
Class: |
384/462 ;
384/572 |
Current CPC
Class: |
F16C 35/06 20130101;
F16C 35/063 20130101; F16C 35/042 20130101; F16C 33/6677 20130101;
F16C 2229/00 20130101; F16C 33/586 20130101; F16C 19/543 20130101;
F16C 33/6651 20130101; F16C 19/386 20130101; F16C 35/073 20130101;
F16C 2226/60 20130101; F16C 2361/61 20130101; F16C 19/385 20130101;
F16C 25/08 20130101 |
Class at
Publication: |
384/462 ;
384/572 |
International
Class: |
F16C 19/00 20060101
F16C019/00; F16C 33/48 20060101 F16C033/48 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 9, 2009 |
DE |
10 2009 032 294.9 |
Claims
1. A bearing assembly comprising: at least one outer ring, an inner
ring unit having at least two inner rings, each inner ring having a
central bore extending in an axial direction, a supporting element
extending through the central bores and supporting the inner rings
in the axial direction, and a plurality of roller bodies rotatably
disposed between the at least one outer ring and each of the inner
rings, wherein a plurality of radially-outer bores also extend in
the axial direction through one of the inner ring unit and the
supporting element and each is configured to receive at least one
attachment device, by which the bearing assembly is affixable on or
to a bearing carrier, wherein the radially-outer bores are spaced
from an axis of axial symmetry of the bearing assembly.
2. A bearing assembly according to claim 1, wherein a chamfer is
defined on a radially-inward edge of at least one of the inner
rings, the chamfer extending continuously in a circumferential
direction of the inner ring and facing the axially-adjacent inner
ring.
3. A bearing assembly according to claim 2, wherein at least one
groove is defined on an outer surface of at least one of the inner
rings on a side facing the axially-adjacent inner ring, the groove
extends radially outward from the chamfer and is formed such that
lubricant is transportable radially outwardly from the chamfer via
the at least one groove between the inner rings.
4. A bearing assembly according to claim 3, wherein the groove is
spiral-shaped.
5. A bearing assembly according to claim 3, wherein the supporting
element has an at least partially hollow interior and a
radially-extending bore is defined in the supporting element such
that lubricant is transportable through the radially-extending bore
from the hollow interior to the at least one chamfer.
6. A bearing assembly according to claim 3, wherein a circular
groove is defined on or in at least one of the inner rings on an
outer side surface that faces away from the other axially-adjacent
inner ring and a radially-extending groove extends from the
circular groove to an inner edge of the at least one inner ring,
wherein lubricant is transportable via the circular groove and the
radially-extending groove to the central bore or to at least one of
the bores for the attachment elements.
7. A bearing assembly according to claim 6, wherein an
axially-extending groove is defined on or in a radially-inner
surface of the central bore of at least one of the inner rings, the
axially-extending groove being formed such that lubricant is
transportable through it between the radially-extending grooves on
opposite outer side surfaces of the at least one inner ring.
8. A bearing assembly according to claim 1, wherein the supporting
element is press-fit in the central bores of the inner rings.
9. A bearing assembly according to claim 1, wherein a securing
groove is defined on an outer circumference of the at least one
outer ring.
10. A bearing assembly according to claim 1, wherein the outer ring
is a part of a toothed gear wheel and has teeth extending radially
outward.
11. A bearing assembly comprising: at least one outer ring, first
and second inner rings disposed axially adjacent to each other,
each inner ring having a first bore extending in an axial direction
along an axis of symmetry of the inner rings, a support extending
through the first bores of the inner rings and supporting the inner
rings in the axial direction, and a plurality of roller bodies
rotatably disposed between the at least one outer ring and each of
the inner rings, wherein at least one lubrication conduit is
defined in or on one or both axially-adjacent side surfaces of the
first and second rings, the at least one lubrication conduit
extending at least partially in a radial direction of the inner
rings and being in fluid communication with a chamber containing
the roller bodies, and wherein a plurality of second bores extend
in the axial direction in parallel with the first bore through one
of the inner rings and the support, each second bore being
configured to receive at least one attachment device, by which the
bearing assembly is affixable on or to a bearing carrier.
12. A bearing assembly according to claim 11, wherein at least a
portion of the at least one lubrication conduit is selected from
the group consisting of a groove, a recess, a channel and a bore
defined in or on at least one of the inner rings.
13. A bearing assembly according to claim 12, wherein the at least
one attachment device is selected from a carriage bolt and a
screw.
14. A bearing assembly according to claim 13, wherein each second
bore has a first portion and a second portion having a diameter
larger than the first portion, the second portion being configured
to receive a head of the attachment device in a countersunken
manner.
15. A bearing assembly according to claim 13, wherein each second
bore has a substantially constant diameter.
16. A bearing assembly according to claim 13, wherein the support
has an at least partially hollow interior configured to receive
lubricant and at least one bore in fluid communication with both
the hollow interior of the support and the at least one lubrication
conduit.
17. An apparatus comprising: a bearing carrier and a bearing
assembly according to claim 13, wherein attachment devices are
disposed in each of the second bores and terminal axial ends of the
attachment devices threadably engage the bearing carrier and
wherein the attachment devices each have a head that is larger than
a body portion disposed within the second bores, the heads at least
partially overlapping the support in the radial direction on an
axial end opposite of the threadable engagement of the attachment
devices with the bearing carrier.
18. An apparatus according to claim 17, wherein the bearing carrier
is one of an engine and an engine housing of a motor vehicle.
19. An apparatus according to claim 18, further comprising gear
teeth disposed on a radially-outer portion of the bearing
assembly.
20. An apparatus according to claim 18, wherein the support has an
at least partially hollow interior configured to receive lubricant
and at least one bore in fluid communication with both the hollow
interior of the support and the at least one lubrication conduit.
Description
CROSS-REFERENCE
[0001] This application claims priority to German patent
application no. 10 2009 032 294.9, filed on Jul. 9, 2009, which is
incorporated fully herein by reference.
TECHNICAL FIELD
[0002] The present invention relates to a bearing assembly
comprising at least one outer ring and an inter ring unit having at
least two inner rings, wherein roller bodies are rotatably disposed
between the at least one outer ring and the inner rings.
BACKGROUND
[0003] Such a bearing assembly is utilized, e.g., as a two-row
tapered roller bearing, in order to rotatably support a toothed
gear wheel in an automobile engine. For example, the outer ring(s)
of two tapered roller bearings are fitted in complementary mating
surfaces of the toothed gear wheel. To attach the toothed gear
wheel to an engine housing, the inner rings are retained, e.g., in
a corresponding attachment unit, so that the toothed gear wheel is
rotatably borne on the engine housing. The attachment unit has an
axially-extending bore designed to receive a screw for threadably
attaching the bearing assembly to the engine housing. Overall,
known bearing assemblies of this type have been characterized by
having a relatively complex construction and by requiring a
time-consuming or expensive installation. In particular, it is
relatively time-consuming and/or expensive to precisely set the
required axial pre-loading or tensioning of the two inner rings of
the tapered roller bearings against each other before the start of
actual operation of the bearing assembly.
SUMMARY
[0004] It is an object of the present teachings to disclose
improved bearing assemblies.
[0005] For example, in one aspect of the present teachings, bearing
assemblies having a simplified construction are taught.
[0006] In another aspect of the present teachings, bearing
assemblies having a lubricant conduit, e.g., one or more grooves,
channels and/or bores, configured to supply lubricating oil, e.g.,
from an engine oil reservoir to the roller bodies are
disclosed.
[0007] In another aspect of the present teachings, bearing
assemblies having advantageous attachment arrangements for
attaching the bearing assemblies to a bearing support or carrier,
e.g., an engine housing, are taught.
[0008] In another aspect of the present teachings, a bearing
assembly may include at least one outer ring and an inner ring unit
having at least two inner rings. A plurality of roller bodies are
rotatably disposed between the at least one outer ring and the
respective inner rings. A plurality of bores preferably extend
through the inner ring unit, e.g., through the inner rings or
through an axial supporting element for the inner rings, in the
axial direction and each bore is shaped so as to accommodate or
receive therein at least one attachment element, such as e.g., a
bolt or screw. The attachment element preferably serves to affix
the bearing assembly to or on a bearing carrier, such as e.g., an
engine housing. The bores are preferably spaced from an axis of
symmetry of the bearing assembly, more preferably they spaced from
the axial symmetry axis. Each inner ring preferably also has an
axially-extending central bore, in which a supporting element is
disposed. The inner rings are axially supportable in a defined
manner by the supporting element.
[0009] Relative to known bearing assemblies, such a bearing
assembly has a noticeably simpler-to-handle structure. For example,
the number of necessary components forming the bearing assembly may
be reduced by providing the attachment bores within the inner ring
unit or the axial supporting element of the bearing assembly.
[0010] In addition or in the alternative, the inner ring unit can
have different constructions that are easily adaptable in
accordance with particular design requirements. Optionally, the
inner ring unit may be pre-assembled as a whole prior to mounting
on the bearing carrier.
[0011] If the attachment bores are spaced from the axis of symmetry
of the bearing assembly, the supporting element can extend through
a central bore, which is aligned or collinear with the axis of
symmetry, in order to axially support the inner rings against or
relative to each other. Such a design may advantageously prevent or
minimize the so-called "run down effect", which sometimes occurs in
tapered roller bearings that must, prior to the start of operation,
revolve a few times under a reduced axial pre-loading of the inner
rings relative to each other in order to set the final, operational
position of the tapered rollers. That is, the tapered rollers
axially migrate towards an axially-outer rim during the initial
revolutions, which is the preferred location of the tapered rollers
during operation of the bearing assembly. Generally speaking, only
in this position of the tapered rollers is a problem-free operation
of the corresponding bearing assembly ensured. Therefore, during
the pre-installation procedure for the two-row tapered roller
bearing, it is often necessary to cause the bearing assembly to
revolve, e.g., about 15 times at a reduced pre-loading of the inner
rings. As soon as the respective tapered rollers have axially
migrated and abut on the respective outer rims in their final
position, the pre-loading or tensioning of the inner rings must
then be increased and maintained, so that the position of the inner
rings is fixed and the tapered rollers do not axially migrate
together again when the bearing assembly enters into operation
again after the final adjustment.
[0012] By disposing the supporting element, which may be a pin or a
centering element, within the axially central bore, this
pre-installation process can be performed more easily and
reliably.
[0013] In addition or in the alternative to the above embodiments,
at least one lubrication conduit may defined on or in at least one
of the inner rings and is preferably configured to communicate
liquid lubricant, e.g. oil, to the roller bodies. The at least one
lubrication conduit is preferably a groove, a recess, a channel
and/or a bore defined in or one at least one of the inner
rings.
[0014] In another aspect of the present teachings, one or both of
the inner rings may have a radially-extending chamfer at or on a
radially-inward edge of the outer or side surface that faces the
axially-adjacent inner ring. Preferably, the outer or side surface
of at least one of the inner rings also has a groove that faces the
axially-adjacent inner ring, which groove(s) extend(s) in the
radial direction outwards from the chamfer(s) and is (are) formed
such that lubricant located on the chamfer(s) is transportable
radially-outward through the groove(s) defined between the inner
rings. By appropriately designing the bearing assembly, it is
possible, e.g., to bring or supply lubricant, e.g., oil, from the
engine compartment to the chamfer(s), e.g., via the above-described
central bore. The oil is then transported radially-outward via the
chamfer(s) and the groove(s) connected thereto to the outer surface
of at least one of the inner rings. The oil then moves between the
two inner rings into a space, where the roller bodies are rotatably
disposed. The oil can be distributed there and thus can lubricate
the roller bodies during operation.
[0015] In another aspect of the present teachings, the groove is
spiral-shaped, which can be produced in a simple manner when
lathing the inner rings during the manufacturing process. For
example, a lathe tool can be started at the chamfer and then drawn
radially-outward while the inner ring makes, e.g., one revolution.
In this case, a spiral-shaped groove results, through which the
lubricant is transportable between the inner rings from the
chamfer. In the alternative, the groove can have any other
arbitrary shape. For example, the groove can extend
radially-outward in a linear or otherwise curved manner from the
inside surface of the inner rings.
[0016] In another aspect of the present teachings, the supporting
element may have an at least partially hollow interior and at least
one bore extending radially outward from the hollow interior. The
bore(s) is (are) preferably designed such that lubricant is
transportable therethrough from the hollow interior of the
supporting element, e.g., to the chamfer(s) and/or groove(s) of the
inner ring(s). If the bearing assembly is mounted, e.g., on an
engine or an engine compartment of a motor vehicle, the hollow
interior can be connected or in communication with the oil
circulation system of the engine, so that lubricant from the engine
is transportable through the radially-extending bore(s) to the
groove(s) between the inner rings and ultimately to the roller
bodies.
[0017] In addition or in the alternative, the supporting element
may be configured to perform a centering function, e.g., the
supporting element may serve to center the inner rings relative to
the axial direction thereof.
[0018] In another aspect of the present teachings, at least one of
the inner rings may have at least one additional groove or channel
on or in its outer side surface that is opposite of the
axially-adjacent inner ring. This additional groove is also
preferably designed to transport lubricant through it to the
central bore or to at least one of the attachment bores.
Preferably, the inner ring(s) of this embodiment has (each have) a
substantially axially-extending groove or channel on or in a
radially-inner surface of the central bore. The substantially
axially-extending groove or channel is preferably formed such that
lubricant is transportable through it between the grooves and/or
channels on or in the respective lateral outer side surfaces. If
such a bearing assembly is mounted on an engine or an engine
housing, oil can be transported from the engine to the outer-lying
groove, then to the central bore, then to the chamfer(s) and then
between the inner rings to the roller bodies, thereby ensuring an
adequate or satisfactory lubrication of the roller bodies.
[0019] In another aspect of the present teachings, the bearing
assembly may include at least one outer ring and an inner ring unit
having at least two inner rings. Roller bodies are again rotatably
disposed between the at least one outer ring and the inner rings. A
plurality of axially-extending bores may be defined in the inner
ring unit and each may be designed to accommodate or receive at
least one attachment element, which is configured to affix the
bearing assembly to a bearing carrier. The axially-extending bores
are preferably spaced from an axis of symmetry of the bearing
assembly, preferably from the axial symmetry axis. In such an
embodiment, substantially the same advantages result that were
already explained in the above-described bearing assemblies.
[0020] The inner ring unit again preferably includes a supporting
element that is disposed within the inner rings, e.g., within a
central bore thereof that is aligned with the axial symmetry axis.
The inner rings can be axially supported in a defined manner by the
supporting element. Further, the attachment bore(s) may optionally
be defined in the supporting element, instead of in the inner
rings.
[0021] In addition or in the alternative, a spacer may be disposed
between the inner rings, thereby separating the inner rings in the
axial direction. A clamping device, e.g., a tensioning disk, may
also be provided. The spacer, the inner rings and the tensioning
disk may be disposed such that an axial pre-loading of the inner
rings, which is definable or settable by the tensioning disk, is
achieved by the attachment element for the bearing assembly mounted
on the bearing carrier.
[0022] Further advantages, features, objects and embodiments of the
invention will be readily derivable from the exemplary embodiments
described in the following in conjunction with the appended
Figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 shows a perspective view of a first exemplary
embodiment.
[0024] FIG. 2 shows an outer view of the exemplary embodiment of
FIG. 1.
[0025] FIG. 3 shows a cross-sectional view of the exemplary
embodiment of FIGS. 1 and 2.
[0026] FIGS. 4 and 5 show two different cross-sectional
illustrations of a second exemplary embodiment.
[0027] FIG. 6 shows a cross-sectional illustration of a third
exemplary embodiment.
[0028] FIG. 7 shows a cross-sectional illustration of a fourth
exemplary embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0029] Each of the additional features and teachings disclosed
below may be utilized separately or in conjunction with other
features and teachings to provide improved bearings and/or bearing
assemblies, as well as methods for designing, constructing and
using the same. Representative examples of the present invention,
which examples utilize many of these additional features and
teachings both separately and in combination, will now be described
in further detail with reference to the attached drawings. This
detailed description is merely intended to teach a person of skill
in the art further details for practicing preferred aspects of the
present teachings and is not intended to limit the scope of the
invention. Therefore, combinations of features and steps disclosed
in the following detail description may not be necessary to
practice the invention in the broadest sense, and are instead
taught merely to particularly describe representative examples of
the present teachings.
[0030] Moreover, the various features of the representative
examples and the dependent claims may be combined in ways that are
not specifically and explicitly enumerated in order to provide
additional useful embodiments of the present teachings. In
addition, it is expressly noted that all features disclosed in the
description and/or the claims are intended to be disclosed
separately and independently from each other for the purpose of
original disclosure, as well as for the purpose of restricting the
claimed subject matter independent of the compositions of the
features in the embodiments and/or the claims. It is also expressly
noted that all value ranges or indications of groups of entities
disclose every possible intermediate value or intermediate entity
for the purpose of original disclosure, as well as for the purpose
of restricting the claimed subject matter.
[0031] In FIG. 1, a perspective view of a first representative
tapered roller bearing assembly 1 is shown, which includes an outer
ring 3 and a plurality of inner rings, of which only one inner ring
5 is shown due to the perspective illustration. A
radially-encircling or circumferentially-extending groove 7 is
defined in radially-outer surface of the outer ring 3. The outer
ring 3 can be connected via this groove 7, e.g., with a
complementary, not-illustrated toothed gear wheel, with a housing
or another element that is desired to rotate during operation. This
connection can take place, e.g., by inserting a securing ring into
the groove 7, which securing ring engages in a corresponding groove
within the toothed gear wheel, housing or other rotatable
element.
[0032] A central bore (21--see FIG. 2) is formed within the inner
rings 5 and a pin 9 is inserted into the central bore. The pin 9
serves to axially support the inner ring 5 shown in FIGS. 1 and 2
with a second inner ring not shown in FIGS. 1 and 2, as will be
further explained below with the assistance of FIG. 3. A plurality
of axially-extending bores 11 are defined within the inner ring 5
and are disposed so as to be spaced relative to the axial symmetry
axis of the bearing assembly 1. The bores 11 preferably serve to
receive carriage bolts, screws or similar attachment devices, by
which the bearing assembly can be attached, e.g., to an engine or
engine housing of a motor vehicle or to another type of bearing
carrier/support.
[0033] FIG. 2 shows a side view of the tapered roller bearing
assembly 1 of FIG. 1. Again, the outer ring 3, one inner ring 5 and
the central bore 21 can be recognized. The pin 9 from FIG. 1 is not
inserted into the central bore 21 shown in FIG. 2 for clarity
purposes, although it is understood that the pin 9 is normally
disposed in central bore 21 during pre-installation and operation
of the bearing assembly 1.
[0034] Although six attachment bores 11 are disposed around the
central bore 21 of FIG. 2, it is understood that fewer (e.g., four,
three or only two) or more (e.g., seven, eight, nine, etc.) bores
can be provided. The attachment bores 11 may be disposed
symmetrically or equidistantly relative to each other or may be
arranged in other ways.
[0035] A plurality of tapered rollers 23 are rotatably disposed
between the outer ring 3 and the inner ring 5 and serve to
rotatably bear the outer ring 3 relative to the inner rings 5.
[0036] The inner ring 5 has a radially-encircling groove or channel
51, e.g., the groove or channel 51 is preferably circular or
torus-shaped. This groove 51 is defined or disposed
radially-outward from the attachment bores 11. A radially-extending
groove or channel 53 is defined in or on the inner ring 5 and
extends from the groove 51 to the central bore 21. In a preferred
embodiment, the tapered roller bearing assembly 1 is mounted on an
engine housing and lubricating oil from the engine is supplied to
the groove 51. The lubrication oil can then be transported along
the groove 51 to the groove 53, regardless of the position of the
actual inflow of the oil into the groove 51, and thereby into the
central bore 21. An axially-extending groove (not illustrated in
FIG. 2) defined or disposed on a radially-inner surface of the
central bore 21 connects to the groove 53. In this case, the
lubricating oil can be transported between the inner rings 5a and
5b via this axially-extending groove. In the alternative, the
groove 53 may be designed to feed into one (or more) of the bores
11 and in this case, the lubricant is communicated therein via a
corresponding groove in an analogous manner. In another
alternative, the groove 53 can be formed in another geometric
shape, e.g., it can be spiral-shaped or otherwise curved.
[0037] FIG. 3 shows a cross-sectional illustration of the tapered
roller bearing assembly of FIGS. 1 and 2 along the axial direction
thereof from the center or axis of symmetry to the radially-outer
edge of the bearing assembly 1.
[0038] This tapered roller bearing assembly 1 includes a one-piece
outer ring 3 having the above-described groove 7 defined in an
axially middle position of the outer ring 3. Two
obliquely-extending track surfaces for tapered rollers 31 are
formed or defined on the lower surface of the outer ring 3. The
bearing assembly 1 includes two inner rings 5a and 5b, each of
which also has a corresponding track surface for the tapered
rollers 31. Thus, the embodiment of FIG. 3 is a two-row tapered
roller bearing assembly 1 in the so-called O-arrangement with a
one-piece outer ring 3 and a two-piece inner ring 5a and 5b. Each
of the two tapered roller bearings comprises a set of tapered
rollers 31 guided in respective cages 33.
[0039] Each of the inner rings 5a and 5b has a central bore 21. The
pin 9 is disposed within the central bore 21 and may preferably
perform at least two functions. For one, a press-fit between the
outer surface of the pin 9 and the inner surface of the central
bore 21 can be achieved by suitably dimensioning the pin 9 and the
central bore 21 of the inner rings 5a and 5b. Due to the press-fit,
e.g., ISO tolerance N6, of the pin 9 in the inner rings 5a and 5b,
an axial pre-loading or tensioning or biasing of the inner rings 5a
and 5b can be defined in a reliable manner. Thus, it is possible,
in particular, to set or determine the amount of the pre-loading or
pre-tensioning of the inner rings 5a, 5b in a well-defined manner
already during the production or pre-installation of the bearing
assembly 1. The pin 9 includes an end portion 37 having a reduced
diameter outside of the intrinsic bearing assembly. A supplemental
stabilizing and/or securing of the bearing assembly 1 can be
achieved by inserting the end portion 37 of the pin 9, e.g., into
an abutting locking washer or a supporting disk, thereby retaining
it.
[0040] The inner rings 5a and 5b each have at least one attachment
bore 11a and 11b, respectively. The bores 11a and 11b extend in the
axial direction through the respective inner rings 5a, 5b. The
inner rings 5a and 5b are arranged so that the bores 11a and 11b
extend in a collinear manner. Each of the bores 11a and 11b has two
portions 39a and 41a, 39b and 41b, respectively, of different
diameters. In this case, for example, a not-illustrated carriage
bolt can be inserted from the right into the bore 11a as shown in
the illustration of FIG. 3. The carriage bolt goes through the
portions 41a, 39a, 39b and 41b and, if it has sufficient length,
its threaded end emerges again from the bore 11b. As a result, the
entire tapered roller bearing assembly 1 can be attached, e.g., to
an engine housing of a motor vehicle via the threads of the
carriage bolt that axially project beyond the bore 11b. The head of
the carriage bolt can be countersunk within the portion 41a of the
inner ring 5 having the larger diameter, so that a compact mounted
structure is achieved, thereby minimizing installation space
requirements.
[0041] In such an embodiment, the portion 41b of the inner ring 5b
having the larger diameter is not necessary for any particular
functional purpose. However, the inner rings 5a and 5b are
preferably constructed identically for manufacturing reasons, so
that the required number of different components for the tapered
roller bearing assembly 1 can be reduced. The assembly 1 as a whole
is preferably mirror-symmetric from the outer ring 3 to the pin 9
relative to a plane extending in the radial direction between the
inner rings 5a and 5b.
[0042] In this embodiment, each of the inner rings 5a and 5b has a
chamfer 61 defined on a lower edge end adjacent to the central bore
21. The chamfer 61 preferably extends in a circumferential manner
entirely around each of the inner rings 5a, 5b. Another
not-illustrated groove or channel preferably extends in the radial
direction from the chamfers 61 along each of the respective facing
side surfaces 63 of the inner rings 5a and 5b and into the hollow
chamber between the tapered roller bodies 31. In the alternative,
such a groove or channel can also be formed only in or on one side
surface 63 of the inner rings 5a or 5b. Such a groove ensures that
lubricating oil, e.g., motor oil from the engine, reaches the
roller bodies 31 during the operation and corresponds to a
groove-like recess 127 of the next embodiment, as will be further
discussed below.
[0043] As was already explained in connection with FIG. 2, the
lubricating oil is received by the groove 51, is then transported
via the groove 53 to the central bore 21 up to the chamfer 61 and
then between the outer surfaces 63 of the inner rings 5a and 5b and
finally to the tapered roller bearings 31. Another groove can be
provided on or in the radially-inner surface of the central bore to
assist in transporting the oil between the inner rings 5a, 5b, as
was discussed above.
[0044] FIG. 4 shows a second representative tapered roller bearing
assembly 101 that includes two tapered roller bearings, each having
an outer ring 103, an inner ring 105, a plurality of roller bodies
107 and a cage 109 for retaining the roller bodies 107. The outer
rings 103 are fitted into corresponding mating surfaces of a
toothed gear wheel 111. The inner rings 105 each have a central
bore and a centering element 113 is inserted in the central bore.
Due to the centering element 113, the inner rings 105 can be
pre-installed in a pre-loaded manner with a press-fit in a manner
analogous to the pin 9 of the exemplary embodiment of FIGS. 1 to
3.
[0045] The inner rings 105 also have attachment bores 115 lying
outside of the axial symmetry axis, which bores 115 are disposed in
a manner analogous to the bores 11 of the embodiment of FIGS. 1 to
3. Attachment screws or bolts 117 may be inserted into the bores
115.
[0046] Further, the centering element 113 has a first hollow space
118 that is separated from a second hollow space 121 by a
separating wall 119. The separating wall 119 has a
radially-encircling or circumferentially-extending recess or
channel 123 and at least one bore 125 extending radially outward
from the recess 123. The function of the bore 125 will be explained
with the assistance of FIG. 5.
[0047] In FIG. 5, the tapered roller bearing assembly 101 of FIG. 4
is shown in a cross-sectional illustration from another angular
position, i.e. the assembly 101 has been rotated about its central
axis relative to the illustration of FIG. 4 so that the
cross-section does not extend through the bore 115 and the
attachment screw 117, but rather extends through the part of the
inner rings 105 that lies between two screws 117. Thus, in FIG. 5,
the bore 125 lies in the plane of the cross-sectional
illustration.
[0048] It is also illustrated here that the inner rings 105 each
have a groove-like recess or channel 127 defined on the outer side
surfaces that face each other in the axial direction. At least one
of the recesses 127 is designed such that the bore 125 is connected
or in communication with the recess 127. Consequently, the hollow
space between the tapered rollers 107 is connected or in
communication with the hollow space 118 of the centering element
113 via the recesses 127 and the bore 125. Lubricating oil from the
engine compartment can flow into the hollow space 118 and then can
be transported via the bore 125 and the recess(es) 127 to the
tapered rollers 107, thereby ensuring an adequate or satisfactory
lubrication of the tapered roller bearing assembly 101 during
operation.
[0049] In the alternative, instead of the recess(es) or channel(s)
127 defined on the inner rings 105, it is possible to provide a
chamfer and a spiral-shaped-extending groove in a manner analogous
to the exemplary embodiment of FIG. 3. If the chamfer is provided,
it is not necessary for the bore 125 to lie directly at the
starting point of the spiral-shaped groove. If the chamfer radially
encircles or circumferentially extends around the entire inner ring
105, the bore 125 is always connected or in communication with the
spiral-shaped-extending groove, thereby ensuring an unhindered flow
of lubricating oil from the hollow space 118 to the tapered rollers
107. The sole prerequisite therefor is that the bore 125 lies
precisely between the inner rings 105 with reference to the axial
direction.
[0050] In contrast to the embodiment of FIG. 3, the attachment bore
115 and the screw head of the screw 117 of this embodiment are
preferably dimensioned to prevent an axial migration of the
centering element 113 in the direction of the screw head. This is
ensured by designing the screw head so that it radially overlaps
the centering element 113, thereby bounding or limiting the axial
movement of the centering element 113. That is, the screw head acts
as an axial stop for the centering element 113.
[0051] A further embodiment of the invention is illustrated in FIG.
6, which is substantially the same as the exemplary embodiment of
FIGS. 4 and 5 with the difference that separate or discrete outer
rings are not present. Instead, the track surfaces for the tapered
rollers 207 are directly machined into the lower surface of the
toothed gear wheel 211. The number of the necessary components is
thus further reduced as compared to the embodiment of FIGS. 4 and
5.
[0052] In FIG. 6, it can also be recognized, in an exemplary
manner, how the bearing assembly 201 may be attached to the engine
housing 231 by a screw 217. The screw 217 goes through the two
inner rings 205 in the axially-extending bores provided therefor
and engages in a corresponding thread in the engine housing
231.
[0053] In the illustration of FIG. 6, the function of the centering
unit 213 is also further demonstrated. The centering unit 213
projects in the axial direction beyond the inner ring 205 that
directly borders the engine housing 231. Thus, the centering unit
213 mates or engages in a corresponding or complementary recess in
the engine housing 231 and thus ensures a perfectly-fitted
centering of the bearing assembly 201 on the engine housing 231. An
axial migration or shifting of the centering element 213 during
operation is thus effectively prevented on the one side by the
engine housing 231 and on the other side by the screw head of the
screw 217.
[0054] In the embodiment of FIGS. 1 to 3, a suitably
axially-elongated pin 9 can perform the function of preventing
axial migration or shifting.
[0055] In FIG. 7, a fourth representative tapered roller bearing
assembly 301 includes outer rings 303 in a manner analogous to the
exemplary embodiments of FIGS. 4 and 5. The outer rings 303 are
fitted into complementary mating surfaces of a toothed gear wheel
305. The tapered roller bearing assembly 301 further includes two
inner rings 307 that are rotatably disposed on the outer rings 303
via two sets of tapered rollers 309. The tapered rollers 309 are
each guided in respective cages 311. A centering element 313 serves
to center the tapered roller bearing assembly 301 in a
not-illustrated housing in a manner analogous to the exemplary
embodiments of FIGS. 4 to 6. It also has a radially-extending bore
315, via which lubricant can be guided to the space between the
tapered rollers 309.
[0056] In contrast to the exemplary embodiments of FIGS. 4 to 6,
the attachment bores 317 are defined in the centering element 313
so as to be spaced in the radial direction from the axial symmetry
axis. The attachment bores 317 are again adapted or designed to
receive, e.g., attachment screws or carriage bolts. Thus, the
tapered roller bearing assembly 301 can be attached to a housing or
a bearing carrier by the screws or bolts extending through the
centering element 313, rather than through attachment bores defined
in the inner rings 307 as in the previous embodiments.
[0057] The inner rings 307 are disposed on a seating surface 321 so
as to be spaced in the axial direction by a spacer element 319
disposed between them. Further, a tensioning ring 323 is provided
that is also disposed on the seating surface 321. The centering
element 321 includes a flange-like extension 325 that extends
radially outward such that it engages behind one of the inner rings
307. When the screws are now inserted into the bores 317 and thus
the tensioning disk is supported on a corresponding housing, a
well-defined axial pre-loading or pre-tensioning of the two inner
rings 307 can be achieved by the cooperation of the tensioning disk
and a defined clamping torque of the screw. The axial pre-loading
or axial clamping of the inner rings 307 is necessary for the
operation of the tapered roller bearing assembly 301 in a manner
similar to the previous embodiments.
[0058] Although many of the lubrication conduits have been depicted
as grooves (e.g., 51, 53, 127, etc.) that are open to the surface,
such lubrication conduits can be embodied as channels or bores that
are completely defined within the inner rings, such that the
lubricant is transported through the inner ring(s) rather than on
an outer surface of the inner ring(s).
REFERENCE NUMBER LIST
[0059] 1 Tapered roller bearing assembly [0060] 3 Outer ring [0061]
5, 5a, 5b Inner ring [0062] 7 Radially-encircling groove [0063] 9
Pin [0064] 11, 11a, 11b Bore [0065] 21 Central bore [0066] 23
Tapered roller [0067] 31 Tapered roller [0068] 33 Cage [0069] 37
Portion of pin 9 having a reduced diameter [0070] 39a, 39b Portion
of bores 11a and 11b, respectively, having a smaller diameter
[0071] 41a, 41b Portion of bores 11a and 11b, respectively, having
a larger diameter [0072] 51 Groove [0073] 53 Groove [0074] 61
Chamfer [0075] 63 Outer side surface of inner rings 5a, 5b [0076]
101 Tapered roller bearing assembly [0077] 103 Outer ring [0078]
105 Inner ring [0079] 107 Tapered roller [0080] 109 Cage [0081] 111
Toothed gear wheel [0082] 113 Centering element [0083] 115 Bore
[0084] 117 Attachment screw [0085] 118 Hollow interior [0086] 119
Separating wall [0087] 121 Hollow interior [0088] 123 Recess [0089]
125 Bore [0090] 127 Recess [0091] 201 Tapered roller bearing
assembly [0092] 205 Inner ring [0093] 207 Tapered roller [0094] 211
Toothed gear wheel [0095] 213 Centering element [0096] 217 Screw
[0097] 231 Engine housing [0098] 301 Tapered roller bearing
assembly [0099] 303 Outer ring [0100] 305 Toothed gear wheel [0101]
307 Inner ring [0102] 309 Tapered roller [0103] 311 Cage [0104] 313
Centering element [0105] 315 Bore [0106] 317 Screw [0107] 319
Spacer element [0108] 321 Seating surface [0109] 323 Tensioning
ring [0110] 325 Extension
* * * * *