U.S. patent application number 13/658093 was filed with the patent office on 2013-02-21 for shaft with roller bearing.
This patent application is currently assigned to SCHAEFFLER TECHNOLOGIES AG & CO. KG. The applicant listed for this patent is SCHAEFFLER TECHNOLOGIES AG & CO. KG. Invention is credited to Peter Solfrank.
Application Number | 20130042990 13/658093 |
Document ID | / |
Family ID | 41060608 |
Filed Date | 2013-02-21 |
United States Patent
Application |
20130042990 |
Kind Code |
A1 |
Solfrank; Peter |
February 21, 2013 |
SHAFT WITH ROLLER BEARING
Abstract
A method for producing a shaft with a roller bearing. The roller
bearing has an inner ring with an outer surface for rolling
elements to roll on. The inner ring of the roller bearing is
embedded, at least partially, into the shaft, which has been
produced using primary forming methods, and the outer surface of
the inner ring is exposed, at least in a part, in the axial
direction and over its entire circumference.
Inventors: |
Solfrank; Peter; (Frensdorf,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SCHAEFFLER TECHNOLOGIES AG & CO. KG; |
Herzogenaurach |
|
DE |
|
|
Assignee: |
SCHAEFFLER TECHNOLOGIES AG &
CO. KG
Herzogenaurach
DE
|
Family ID: |
41060608 |
Appl. No.: |
13/658093 |
Filed: |
October 23, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12421998 |
Apr 10, 2009 |
|
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13658093 |
|
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Current U.S.
Class: |
164/98 |
Current CPC
Class: |
F16C 33/605 20130101;
F16C 2226/30 20130101; Y10T 29/49645 20150115; F16C 2361/53
20130101; F16C 3/02 20130101; F16C 35/063 20130101; F16C 19/46
20130101; F16F 15/267 20130101 |
Class at
Publication: |
164/98 |
International
Class: |
B22D 19/00 20060101
B22D019/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 12, 2008 |
DE |
102008018545.0 |
Claims
1. A method for producing a balance shaft with roller bearing,
wherein the roller bearing includes an inner ring, which is
produced from roller bearing steel, the method comprising:
inserting the inner ring into a primary forming tool of the shaft,
forming the shaft by a casting or sintering method in such a manner
that the inner ring is at least partially embedded and at least a
portion of an outer surface of the inner ring is exposed in an
axial direction over an entire circumference of the outer
surface.
2. The method according to claim 1 wherein the roller bearing also
includes a thrust washer and a portion of the thrust washer is
embedded into the balance shaft on a side of the inner ring.
3. The method according to claim 1, wherein after casting or
sintering of the balance shaft, the outer surface of the inner ring
is machined, heat-treated and finished.
Description
INCORPORATION BY REFERENCE
[0001] The following documents are incorporated herein by reference
as if fully set forth: U.S. application Ser. No. 12/421,998, filed
Apr. 10, 2009.
BACKGROUND
[0002] The expansion of a gas in a cylinder exerts work on a piston
and which is transmitted to the crankshaft by means of a connecting
rod. The oscillating movement of the piston is converted into a
rotating movement in this way. As a consequence of the
reciprocating movement of the piston and connecting rod and as a
consequence of the irregular transmission behavior of the crank
mechanism, inertia forces occur that are supported in motor
bearings and induce vibrations in adjacent structures. The inertia
forces of the linearly displaced parts of the crank mechanism, that
is the oscillating masses, can be represented approximately by
means of a formula based on a series expansion, in which inertia
forces of first and second order are defined. Theoretically, not
only first and second orders occur but an infinite number of orders
that are, however, insignificant from the third order in the
majority of cases on account of their small size.
[0003] The rotating masses of the crank mechanism can be balanced
by counterweights on the crankshaft.
[0004] Oscillating inertia forces of the first and second order can
be avoided or reduced in the case of multicylinder engines by
arranging the cylinders in a skillful manner. Balance shafts are
often used for in-line engines with less than 6 cylinders and
V-type engines with less than 8 cylinders. In order to balance
inertia forces of the second order, at least 6 cylinders are
required for an in-line engine or 8 cylinders for a V-type engine,
or balance shafts on which corresponding counterweights rotate at
double the crankshaft speed.
[0005] Balance shafts, therefore, are used to reduce or eliminate
the free inertia forces of a reciprocating piston engine in order
to reduce operating noise and vibrations. The counterweights or
eccentric weights mounted on the balance shaft oppose the inertia
forces generated by the crank mechanism. The balance shafts are
driven synchronously by the crankshaft by means of gear wheels,
chains or toothed belts. One or two balance shafts are used in the
majority of cases depending on the engine design.
[0006] The design of balance shafts is based on the common
principles of creating a mass arrangement between bearing points
outside the axis of rotation, said mass arrangement providing the
imbalance. Balance shafts that are provided with partial bearings
or those where the roller bearing rolls directly on the balance
shaft are also known.
[0007] In order to provide shafts with a roller bearing raceway,
they must either be produced completely from roll-resistant steel
or must include a roll-resistant inner ring. Where roll-resistant
steel, which is expensive to purchase, is used there is an
additional disadvantage that, for shaping, said steel has to be
rolled or forged at high temperatures using expensive tools and
then at least the region on which the rolling elements will
subsequently roll has to be heat-treated and machined. Where a
roll-resistant inner ring is used on a shaft, the shaft material
can certainly be selected within wide boundaries but the region of
the shaft against which the inner ring of the roller bearing abuts
has to be machined such that said region forms an interference fit
with the inner ring. Therefore precise machining of both the inner
surface of the inner ring and also the bearing seat on the shaft is
necessary. As the interference fit works with radial pressing
forces, a partial bearing is eliminated, as a roller bearing inner
ring in the form of a sector or segment is not capable of producing
the required radial pressing forces because of the lack of internal
stress.
[0008] DE 10 2007 009 800 A, for example, shows a balance shaft for
a multiple cylinder engine with a counterweight section and a
bearing point, the bearing point having a radial bearing surface
that extends only partially over a periphery of the bearing point.
If the bearing point is not sufficient for the long service life of
a roller bearing, a raceway is provided at the bearing point, said
raceway being positively bonded to the bearing point by means of
soldering or welding.
SUMMARY
[0009] It is the object of the invention to develop a shaft with
roller bearing arrangement such that the selection of material for
the shaft can be within wide boundaries, that the precise machining
of the inner surface of the roller bearing inner ring and of the
bearing seat on the shaft is omitted at least on one of the two
elements and that partial bearing arrangements can also be used. In
addition, the production expenditure is to be reduced with no loss
of quality compared with previous production methods.
[0010] The object of the invention is achieved through one or more
aspects of the invention described below. Of the primary forming
techniques possible for the creation of workpieces, the casting
method with all its variants or the sintering method are usually
used for the shaft. Consequently, all materials that are sinterable
and/or castable can be used to produce the shaft. The embedding of
an inner ring into the shaft offers the advantage of it being
possible for said inner ring to be produced from a completely
different material to the shaft itself. Embedding the inner ring
into the shaft produces axial as well as radial securement. This
securement produces a positive-locking interconnection between
shaft and inner ring. This interconnection can only be separated by
destroying one of the two parts.
[0011] The shaft can certainly embed the entire inner ring but in
this case portions are also sufficient. It would also be possible,
for example, to accommodate the inner ring by means of spokes
distributed over the circumference of the shaft. The spokes at the
end facing the inner ring would encompass the inner ring in a
U-shaped manner to the effect that the spoke would grip the inner
surface and both side surfaces of the inner ring. It is also not
necessary in this case for the shaft to be situated in the center
of the inner ring, it can also be formed eccentrically relative to
the inner ring. The inner ring can also, for example, be embedded
into the shaft only in sectors or segments.
[0012] The shaft can also be developed such that in a partial
region in the radial direction the shaft extends further than the
outer surface of the inner ring.
[0013] In a preferred development of the invention, the roller
bearing also includes a roller bearing cage, which can be threaded
over one end of the shaft as far as over the inner ring. Thus, from
one end of the shaft, an outer ring of the roller bearing and a
roller bearing cage can be moved over the inner ring. This
possibility is used, for example, to introduce a shaft with inner
ring into a roller bearing outer ring with assembled rolling
elements that is pre-assembled in a housing, for example an engine
block, in such a manner that the inner ring abuts against the
roller bearing outer ring. The end of the shaft is realized such
that the shaft with inner ring can be threaded in an optimum manner
and none of the components, more especially none of the roller
bearing components are damaged.
[0014] In a preferred development of the invention, the inner ring
is embedded into the shaft in an angular range that is greater than
180.degree., but less than 360.degree.. Consequently, one or more
hollow spaces can be provided between the shaft and the inner ring.
Naturally, this development makes it possible for the region in
which the inner ring is embedded into the shaft to be contiguous.
Consequently, imbalances can be generated, for example, in a
targeted manner in the bearing region. By embedding the inner ring
in an angular range that is greater than 180.degree., the inner
ring is secured in such a manner that the inner ring cannot be
displaced in the radial direction relative to the shaft. In
addition, a positive-locking connection is created between shaft
and inner ring and, consequently, a permanent connection.
[0015] In another preferred development of the invention, a portion
of the inner ring is embedded into the shaft over the entire width
of the inner surface. Thus it is possible, for example, to
concentrate material from which the shaft is made on one side of
the inner ring. If this region is not sufficient for the positive
connection because the angle at which the inner ring is embedded
into the shaft is smaller than 180.degree., support pieces or
spokes, which are integrally formed on the shaft, can be drawn up
along the inner ring until a positive-locking connection between
shaft and inner ring is realized. These support pieces or spokes do
not have to run over the entire width of the inner surface of the
inner ring. These support pieces or spokes, when viewed in the
axial direction of the inner ring, can also engage the inner ring
offset from the center.
[0016] In an advantageous manner, a portion of the outer surface of
the inner ring is embedded into the shaft. This means that the
inner ring is surrounded by the shaft in a portion at least at one
end. This provides a possibility of increasing the positive locking
between shaft and inner ring. Also known are roller bearings with
roller bearing cages that, on the one hand, are slotted and, on the
other hand, are made from such plastics material that said roller
bearing cages can be bent open so far that they can be pushed
directly over the inner ring. The corresponding roller bearing
outer rings are divided and consequently comprise two half shells.
As a consequence of this roller bearing form, the inner ring, on
the one hand, can be embedded into the shaft such that the shaft
encloses the edge regions of the outer surface of the inner ring
completely on both sides. Consequently, the extension of the shaft
in the radial direction over the entire circumference is greater
than the extension of the outer surface of the inner ring. On the
other hand, because of this roller bearing form, the height by
which the surface of the shaft protrudes beyond the outer surface
of the inner ring is not, in principle, subject to any limit.
[0017] In a preferred embodiment of the invention, the roller
bearing also includes a thrust washer, a portion of the thrust
washer being embedded into the shaft to the side of the inner ring.
The embedding of one or two thrust washers makes it possible to use
roller bearings that have inner rings that have to be guided on one
side or on both sides in an axial manner relative to the rolling
elements. These thrust washers can also be used with shafts where
the shaft extends in a partial region in the radial direction
further than the outer surface of the inner ring and consequently
forms a shoulder. The outside of the thrust washer remote from the
inner ring borders in a portion on this shoulder of the shaft. The
thrust washers are responsible in operation for ensuring that the
rolling elements, which are rotatably connected to a rolling
element cage and rotate relative to the inner ring, are positioned
precisely over the inner ring. In this case, it is insignificant
whether the rolling element cage or the rolling elements are guided
by the thrust washers.
[0018] Said thrust washers can also be used for shafts where the
entire extension region of the shaft in the radial direction is
smaller than the extension region of the outer surface of the inner
ring.
[0019] In an expedient manner, the inside diameter of the thrust
washer is not smaller than the inside diameter of the inner ring.
This avoids constriction of the shaft in the region of the thrust
washer and the consequently resultant weakening of the shaft
relative to forces applied to it. In this case, these are
predominantly torsional forces, but bending forces also affect the
shaft.
[0020] In another preferred embodiment of the invention, the thrust
washer is in the form of a sector, which encloses an angle that is
greater than the load area of the roller bearing in the radial
direction. Particularly with shafts that are to generate imbalance,
it is undesirable to impinge upon the side situated radially
opposite the imbalance with weight. In order to balance out this
weight again, possibly the same weight has to be supplied to the
imbalance side. The embedding of the thrust washer into the shaft
results, in this case too, as in the case of the inner ring, in a
positive locking and permanent connection between shaft and thrust
washer. As the imbalance can be generated in a sector that is
smaller than 180.degree., the thrust washer sector is also formed,
where possible, smaller than 180.degree.. If the thrust washer
falls below an angle of 180.degree., design measures, for example
undercutting, must ensure that the thrust washer cannot become
detached from the shaft.
[0021] In an advantageous manner, one of the two end portions of
the thrust washer produced by the sector shape is realized as
insertion inclination. The said insertion inclination on the thrust
washer guarantees a smooth introduction into a central position
over the inner ring of rolling elements or their rolling element
cages, possibly exhibiting a small amount of play in the axial
direction. In addition, the wedge-shaped gap created by the
insertion inclination between rolling element or rolling element
cage and thrust washer enables the build-up of a good lubricant
film. If the shaft only has one direction of rotation in operation,
it can be sufficient to form only one edge region of the thrust
washer as insertion inclination. Appropriately, the end portion
opposing the direction of rotation is used for this purpose.
[0022] In an expedient manner, the inner surface and/or a side
surface of the inner ring is structured. On the one hand, the
application of a structure increases the surface of the inner ring
and consequently the connecting surface to the shaft. On the other
hand, the positive locking of the shaft to the inner ring is
improved by means of macroscopic indentations. The structure does
not have to have a regular pattern. A roughness generated by sand
blasting, for example, can be sufficient for the structure desired
in this case. Depending on the production method, it may be
expedient to structure only those portions that get embedded into
the shaft. Structures may also be applied on portions of the outer
surface of the inner ring, which are subsequently embedded into the
shaft. This implementation can also be used for the thrust
washers.
[0023] In a preferred embodiment of the invention, the inner ring
includes a passage. Said passage, if it is embedded into the shaft,
can increase the positive locking of the shaft to the inner ring
even further. The passage, however, can only be present in the
region of the inner ring that is not embedded into the shaft.
Lubricant, preferably oil mist, can pass through this opening from
the inside of the inner ring to the outer surface by means of
centrifugal force. The shape of the opening can be optimized for
supplying the lubricant. For example, the central axis of the
opening, when seen in the viewing direction of the axis of rotation
of the inner ring, can be in the form of a section of an ellipse or
of an evolvent. With the opening developed in this manner, however,
the optimum lubricant supply emerges only in one direction of
rotation of the shaft.
[0024] In another preferred development of the invention, the
passage is in the form of a radial bore. Radial bores are simple to
produce and are consequently very inexpensive. Although it is true
that supplying lubricant through a radial bore is not as optimal as
can be obtained in the case of a development according to the
description in the previous paragraph, however, an inner ring with
a radial bore has no preferred direction of rotation. Consequently,
the danger of embedding the inner ring into the shaft in the wrong
direction can be avoided.
[0025] In another advantageous development of the invention, the
passage extends centrally in the axial direction in the inner ring.
By way of the central arrangement of the passage, the inner ring
can be embedded into the shaft in an arbitrary manner as there is
no preferential direction in which the inner ring has to be
orientated relative to the shaft. In addition, the central
arrangement of the passage guarantees a uniform distribution of
lubricant to the edges of the outer surface of the inner ring.
[0026] The inner ring has a width and a circumference, wherein in
an advantageous manner the width changes along the circumference.
Precisely when forces act on the shaft in the radial direction on
one side and rotate with it--as is the case, for example, with
balance or imbalance shafts--the inner ring embedded in the shaft
is loaded more in the region of the imbalance than in the region
situated diametrally opposite. As the stability under load of a
bearing precisely when needle bearings are used also depends on the
width of the inner ring, the width of the inner ring can
consequently be adapted to the load actually occurring. This means
that it is possible to design the inner ring with a narrower width
compared to the region in which the load occurs and thereby save
weight. Precisely this weight saving is a decisive advantage for
balance or imbalance shafts.
[0027] If a portion of the shaft extends in the radial direction
further than the outer surface of the inner ring, the inner ring
has a constant width in this portion. If a thrust washer sector is
embedded into the shaft adjacent to the inner ring, the width of
the inner ring remains constant along the thrust washer sector in
this case too.
[0028] A weight saving can also be achieved if, instead of reducing
the width of the inner ring, the thickness of the inner ring is
reduced, for example. This can also be achieved, for example, in
that the inner surface and the outer surface of the inner ring are
each defined by an even circular cylinder, the central axes of
which, although parallel, are spaced apart by a predetermined
distance. The inner ring is embedded into the shaft in such a
manner that the inner ring has the greatest thickness at the
location with the highest load, said thickness continuously
reducing over a semi-circle up to the location with the lowest
load. Naturally, it is also possible to have a combination between
this development and the reduction in width.
[0029] The inner ring is preferably shaped in the form of an inner
ring sector. This solution can only be applied to a shaft where one
side of the inner ring is totally unloaded in operation. This
occurs preferably in the case of imbalance or balance shafts. The
sector without the inner ring is situated at the side situated
opposite the imbalance. Naturally, the thickness of the inner ring
can be continuously reduced relative to the inner ring sector edges
if additional weight savings need to be made.
[0030] In another advantageous embodiment of the invention, the
inner ring sector encloses an angle that is greater than
180.degree.. This development guarantees that when the
shaft--preferably an imbalance shaft or a balance shaft--remains
still, the inner ring remains connected to the outer ring by means
of the rolling elements. With an enclosed angle of less than
180.degree., the inner ring sector can be lifted from the roller
bearings. This can result in damage to the roller bearing when the
shaft starts up.
[0031] In an expedient manner, the inner ring is produced from
roller bearing steel. Consequently, the inner ring can be realized
as a roller bearing inner ring. This means that the inner ring can
be machined, heat-treated and polished. Consequently, it is
possible to create the contour at the outer surface of the inner
ring necessary to accommodate the corresponding rolling element. A
hardness equivalent to the rolling elements and the outer ring of
the roller bearing can be created by means of the heat treatment.
This guarantees that the bearing has a long service life.
[0032] In an advantageous manner, the shaft is in the form of a
balance shaft. The advantages referred to can be utilized precisely
with a balance shaft or an imbalance shaft. Thus such a shaft, for
example, can be mounted by means of needle bearings, the bearing
points being situated in the region of the imbalances. It is also
possible to utilize one bearing point as a fixed bearing and the
other as a loose bearing, whereas with the loose bearing
arrangement the shaft with inner ring is not guided in the axial
direction relative to the outer ring. A thrust washer can also
serve as securement in the axial direction in the case of the fixed
bearing arrangement.
[0033] In another advantageous manner, the balance shaft can be
used in a reciprocating piston engine. Reciprocating piston engines
with few cylinders, especially the most common four-cylinder
in-line engines, vibrate on account of inertia forces of the second
order. By means of two balance shafts running at double speed
parallel to the crankshaft and rotating in opposing directions with
respect to one another, the vibration of the reciprocating piston
engine can be reduced, as can be seen in practice in the Lanchester
balance system. A balance shaft is also used in the increasingly
produced six-cylinder V-type engines in order to eliminate
vibrations occurring due to the design.
[0034] According to the invention, the inner ring is inserted into
the primary forming tool of the shaft that is to be produced by
means of primary forming techniques in such a manner that the inner
ring is at least partially embedded and the outer surface of the
inner ring is exposed in the axial direction in a portion and over
its entire circumference.
[0035] In another specific embodiment of the invention, the shaft
also has a thrust washer and a portion of the thrust washer is
embedded into the shaft to the side of the inner ring.
[0036] In a preferred development of the invention, the outside of
the inner ring is machined, heat-treated and finished. The inner
ring is inserted into the primary forming tool as a prefabricated
even circular hollow cylinder, where the inner surface of the inner
ring is possibly structured to increase the surface. Once the shaft
with the inner ring embedded therein has been prepared, the outer
surface of the inner ring is machined to its approximate outer
contour, the inner ring is then hardened and tempered, usually in
an inductive manner and, as the final step, the said outer surface
is polished to size and, if necessary, honed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0037] Further details and advantages of the invention proceed from
the sub claims in conjunction with the description of an exemplary
embodiment, which is explained in more detail by way of the
drawings.
[0038] In which:
[0039] FIG. 1 is a sectional representation of a shaft with roller
bearing according to the invention, an inner ring being embedded
into the shaft in a circumferential manner;
[0040] FIG. 2 is a sectional representation of another development
of the shaft with roller bearing according to the invention, where
the inner ring is embedded into the shaft only partially in the
radial direction and over its entire width in the axial
direction;
[0041] FIG. 3 is a sectional representation of another development
of the shaft with roller bearing according to the invention, where
the inner ring is embedded into the shaft only in portions in the
radial direction and in the axial direction;
[0042] FIG. 4 is a sectional representation of another development
of the shaft with roller bearing according to the invention, where
the inner ring is embedded into the shaft only in portions in the
radial direction and in the axial direction and the radial
extension of the inner ring is smaller than the extension of the
shaft;
[0043] FIG. 5 is a sectional representation of another development
of the shaft with roller bearing according to the invention, where
the inner ring is embedded into the shaft only in portions in the
radial direction and in the axial direction and the inner ring has
a radial bore;
[0044] FIG. 6 is a sectional representation of another development
of the shaft with roller bearing according to the invention, where
the inner ring is embedded into the shaft only in portions in the
radial direction and in the axial direction, the inner ring has a
radial bore and is provided with a thrust washer;
[0045] FIG. 7 is a sectional representation of another development
of the shaft with roller bearing according to the invention, where
the inner ring is embedded into the shaft only in portions in the
radial direction and in the axial direction and the width of the
inner ring changes along its circumference;
[0046] FIG. 8 is a sectional representation of another development
of the shaft with roller bearing according to the invention, where
the inner ring is embedded into the shaft only in portions in the
radial direction and in the axial direction, the width of the inner
ring changes along its circumference and the thrust washer is
realized as a sector with insertion inclination; and
[0047] FIG. 9 is a sectional representation of another development
of the shaft with roller bearing according to the invention, where
the inner ring is embedded into the shaft only in portions in the
radial direction and in the axial direction, the width of the inner
ring changes along its circumference and the outer surface of the
inner ring is partially embedded into the shaft.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0048] It must be noted at this point that identical parts in the
individual figures also have identical references.
[0049] FIG. 1 shows a shaft 1 constructed using primary forming
techniques, said shaft having a surface 7, into which an inner ring
2 of a roller bearing is embedded. The inner ring 2 is produced
from roller bearing steel. The inner ring 2 has an inner surface 3,
two side surfaces 4 and an outer surface 5. The inner ring 2 is in
the form of a rotationally symmetrical hollow cylinder with a
central axis 6. The shaft 1 is also rotationally symmetrical. Both
the central axis 6 of the inner ring 2 and the central axis of the
shaft 1 are congruent. The embedding of the inner ring 2 is
effected in such a manner that the inner surface 3 and a portion of
the two side surfaces 4 are surrounded by the material of the shaft
1 in such a manner that each point on the outer surface 5 is
further away radially from the central axis 6 than each point on
the surface 7 of the shaft 1. In order to guarantee better positive
locking of the inner ring to the shaft, the inner surface 3 and the
side surfaces 4 are sand blasted or provided with a structure.
[0050] FIG. 2 shows a cast shaft 8, where the material is present
essentially only on one side of the inner ring 2. In this case too,
the embedding of the inner ring 2 into the shaft 8 is effected in
such a manner that the inner surface 3 and a portion of the two
side surfaces 4 are surrounded by the material of the shaft 8 such
that each point on the outer surface 5 is further away radially
from the central axis 6 than each point on the surface 11 of the
shaft 8. However, the inner ring 2 is only embedded in a portion
such that a hollow space 12 is produced between the shaft 8 and the
inner ring 2. An elevation 9 is fixedly connected to the shaft 8,
said elevation embedding the entire width 10 of the inner surface 3
of the inner ring 2 and a portion of the side surfaces 4. The
elevation 9 in conjunction with the shaft 8 embeds the inner ring 2
in a sector that is greater than 180.degree.. This guarantees a
positive-locking, permanent connection between shaft 8 and inner
ring 2.
[0051] The shaft 13 represented in FIG. 3 differs from the shaft
represented in FIG. 2 in that the elevation 14 does not extend over
the entire width of the inner ring 2 but rather along the inner
surface 3 of the inner ring 2. The elevation 14 is consequently
narrower than the inner ring 2 is wide. As the elevation 14 in
conjunction with the shaft 13 also embeds the inner ring 2 in a
sector larger than 180.degree. at least in a portion, axial and
radial securement of the inner ring 2 is guaranteed.
[0052] The shaft 15 represented in FIG. 4 differs from the shaft 13
represented in FIG. 3 in that the outer surface 5 of the inner ring
2 is offset in a portion in the radial direction relative to the
outer surface 18 of the shaft 15. This results, on the one hand, in
an increase in the imbalance of the shaft with reference to the
axis of rotation 6. On the other hand, the flanks 17 created in
this manner and extending flush with the side surfaces 4 of the
inner ring 2, can be utilized to guide the rolling elements or the
rolling element cage in the axial direction.
[0053] The inner ring 19 represented in FIG. 5 differs from the
inner ring 2 represented in FIG. 3 in that the inner ring 19, in
the region of the hollow space 12, has at least one bore 20 that is
centrally disposed and extends in the radial direction. Said bore
20 is used in operation to move lubricant, more especially oil
mist, by means of centrifugal force from the hollow space 12 to the
rolling element cage or rolling element (not represented here)
rolling on the outer surface 21.
[0054] FIG. 6 shows the inner ring 19 known from FIG. 5 with its
bores 20. The outer surface 21 of the inner ring 19 is offset in
the radial direction in a portion relative to the surface 28 of the
shaft 22. A thrust washer 24 is situated flush with the inner ring
19 on each side of the inner ring 19 in such a manner that the
inner surface 25 of the thrust washer 24 contacts the side surface
26 of the inner ring 19. In addition, the inside diameter of the
thrust washer 24 is as large as the inside diameter of the inner
ring 19. The central axis of the thrust washer 24 is also
orientated relative to the central axis 6 of the inner ring 19 such
that they are in alignment together. Said arrangement guarantees
that the shaft does not become more constricted than as effected by
means of the inner ring 19. On the side remote from the inner ring
19, the thrust washer 24 has an outer surface 27, which is
connected to the material of the shaft 22. The shaft 22 embeds the
entire width of an inner surface 29 of the inner ring 19. An
elevation 23 is fixedly connected to the shaft 22, said elevation
no longer extending over the entire width of the inner ring 2, but
only in a portion along the inner surface 29. The elevation 23 in
conjunction with the shaft 22 embeds the inner ring 19 in a sector
that is greater than 180.degree.. Additional structuring of the
outer surface 27 of the thrust washer 24 provides a good
positive-locking connection between the thrust washer 24 and the
shaft 22. The thrust washers 24 provide axial guiding for the
rolling element cage or the rolling elements.
[0055] FIG. 7 shows another development of the shaft 13 with inner
ring 2 shown in FIG. 3. In this case, the width of the inner ring
30 extends constantly over a sector of 180.degree.. in the region
that is embedded into the shaft 13 with its elevations 14, and is
then continuously reduced by 90.degree. to a web 31. In this case,
the inner ring 30 is optimized to the forces working on it in
operation. As the imbalance loads one side of the inner ring 30
more than the other, this can be used to adapt the load capacity of
the inner ring 30 to the forces actually prevailing in
operation.
[0056] FIG. 8 shows the inner ring 30 represented in FIG. 7 in
conjunction with the shaft 22 shown in FIG. 6. The thrust washer
32, in this case, is in the form of a sector that is greater than
180.degree.. The thrust washer 32 is positioned relative to the
shaft 22 such as is described in FIG. 6. The sector edge regions of
the thrust washer 32 that are not embedded into the shaft 22 are
bent away from the inner ring 30 and serve as insertion inclination
33 for rolling elements or their rolling element cage (not shown in
this case) and consequently as an axial guide. The rolling
elements, in this exemplary embodiment, are guided by the thrust
washers 32 in the region of the inner ring 30 at which the highest
load occurs.
[0057] FIG. 9 shows the inner ring 30 represented in FIG. 7 in
conjunction with a shaft 36 and the elevations 14 that are fixedly
connected to said shaft and extend on the inside 37 of the inner
ring 30. On its outer surface 34 to the sides, the inner ring has
edge regions 35 that are surrounded by the material of the shaft
36.
[0058] The shaft is produced by the semifinished inner ring being
inserted into the primary forming tool. The shaft is then prepared
using sintering methods or casting methods. The outer surface of
the inner ring is then machined, inductively hardened, tempered,
polished and possibly honed.
[0059] A first machining of the inner ring embedded in the shaft
may be necessary as the inner ring becomes deformed in certain
circumstances through the heat created by the casting process, such
that it would be too time-consuming and consequently too expensive
to balance it out only by means of a grinding process.
[0060] An outer surface of the inner ring embedded in the shaft and
produced in this manner can be used in an excellent manner as a
bearing surface for a friction bearing.
[0061] It must also be pointed out that "one" or "a" does not
exclude the plural. In addition, it must be pointed out that
features or steps that have been described with reference to one of
the above exemplary embodiments, can also be used in combination
with other features or steps of other above described exemplary
embodiments. References in the claims are not to be seen as
restrictions.
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