U.S. patent application number 10/189661 was filed with the patent office on 2003-01-09 for belt tensioning device.
Invention is credited to Asbeck, Jochen, Berndt, Thomas, Bonse, Rudolf, Jud, Joachim.
Application Number | 20030008739 10/189661 |
Document ID | / |
Family ID | 7690266 |
Filed Date | 2003-01-09 |
United States Patent
Application |
20030008739 |
Kind Code |
A1 |
Asbeck, Jochen ; et
al. |
January 9, 2003 |
Belt tensioning device
Abstract
A tensioning device for attraction mechanism including a
receiving and mounting housing, a roller carrier pivotably
connected to the mounting housing, a bearing which radially
supports the roller carrier relative to the mounting housing, a
spring between the roller carrier and the mounting housing for
applying a tensioning force, and a damping device. The damping
device includes a damping bush which, by friction, dampens any
movement between the roller carrier and the mounting housing in
such a way that damping is greater in the direction of an
increasing tension force than in the direction of decreasing
tension force. A flat band spring applies the friction force to the
damping bush. The flat band spring is secured, at a first end, to
the receiving and mounting housing in a rotationally fast way, and
at a second end to the damping bush in a rotationally fast way.
Inventors: |
Asbeck, Jochen; (Attendorn,
DE) ; Berndt, Thomas; (Hof, DE) ; Jud,
Joachim; (Daaden, DE) ; Bonse, Rudolf;
(Attendorn, DE) |
Correspondence
Address: |
Robert P. Renke
Suite 250
28333 Telegraph Road
Southfield
MI
48034
US
|
Family ID: |
7690266 |
Appl. No.: |
10/189661 |
Filed: |
July 3, 2002 |
Current U.S.
Class: |
474/135 ;
474/133 |
Current CPC
Class: |
F16H 2007/084 20130101;
F16H 7/1218 20130101; F16H 2007/081 20130101 |
Class at
Publication: |
474/135 ;
474/133 |
International
Class: |
F16H 007/12 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 5, 2001 |
DE |
101 31 916.9 |
Claims
What is claimed is:
1. A tensioning device for a traction mechanism comprising: a
receiving and mounting housing; a roller carrier pivotably
connected to the receiving and mounting housing; a bearing which
radially and axially supports the roller carrier relative to the
receiving and mounting housing; a spring for applying a tensioning
force, which spring is arranged between the roller carrier and the
receiving and mounting housing; a damping device comprising a
damping bush which, by friction, dampens any movements between the
roller carrier and the receiving and mounting housing in such a way
that the damping effect is greater in the direction of an
increasing tensioning force than in the direction of a decreasing
tensioning force, and a flat band spring applying a friction force
to the damping bush, the flat band spring at a first end being
secured to the receiving and mounting housing in a rotationally
fast way and, at its second end being secured to the damping bush
in a rotationally fast way.
2. A tensioning device according to claim 1 wherein the damping
bush comprises a resilient material.
3. A tensioning device according to claim 1 wherein the damping
bush comprises a slot for diameter-reduction.
4. A tensioning device according to claim 1 wherein at its first
end, the flat band spring is secured to the receiving and mounting
housing in a form-fitting or material-locking way.
5. A tensioning device according to claim 2 wherein at its first
end, the flat band spring is secured to the receiving and mounting
housing in a form-fitting or material-locking way.
6. A tensioning device according to claim 3 wherein at its first
end, the flat band spring is secured to the receiving and mounting
housing in a form-fitting or material-locking way.
7. A tensioning device according to claim 4 wherein at its first
end, the flat band spring is held in a mounting slot provided at
the receiving and mounting housing.
8. A tensioning device according to claim 5 wherein at its first
end, the flat band spring is held in a mounting slot provided at
the receiving and mounting housing.
9. A tensioning device according to claim 6 wherein at its first
end, the flat band spring is held in a mounting slot provided at
the receiving and mounting housing.
10. A tensioning device according to claim 1 wherein at its second
end, the flat band spring is fixed to the damping bush in a
form-fitting or material-locking way.
11. A tensioning device according to claim 2 wherein at its second
end, the flat band spring is fixed to the damping bush in a
form-fitting or material-locking way.
12. A tensioning device according to claim 3 wherein at its second
end, the flat band spring is fixed to the damping bush in a
form-fitting or material-locking way.
13. A tensioning device according to claim 4 wherein at its second
end, the flat band spring is fixed to the damping bush in a
form-fitting or material-locking way.
14. A tensioning device according to claim 10 wherein at its second
end, the flat band spring is held in a fixing slot provided in the
damping bush.
15. A tensioning device according to claim 11 wherein at its second
end, the flat band spring is held in a fixing slot provided in the
damping bush.
16. A tensioning device according to claim 12 wherein at its second
end, the flat band spring is held in a fixing slot provided in the
damping bush.
17. A tensioning device according to claim 13 wherein at its second
end, the flat band spring is held in a fixing slot provided in the
damping bush.
18. A tensioning device according to claim 3 wherein at its second
end, the flat band spring is held in the slot for
diameter-reduction of the damping bush.
19. A tensioning device according to claim 1 wherein the bearing
comprises a bearing bush connected to the roller carrier and a
bearing pin connected to the receiving and mounting housing.
20. A tensioning device according to claim 4 wherein the bearing
comprises a bearing bush connected to the roller carrier and a
bearing pin connected to the receiving and mounting housing.
21. A tensioning device according to claim 10 wherein the bearing
comprises a bearing bush connected to the roller carrier and a
bearing pin connected to the receiving and mounting housing.
22. A tensioning device according to claim 19 wherein the bearing
bush comprises a bearing sleeve providing radial support and a
bearing collar providing axial support.
23. A tensioning device according to claim 20 wherein the bearing
bush comprises a bearing sleeve providing radial support and a
bearing collar providing axial support.
24. A tensioning device according to claim 21 wherein the bearing
bush comprises a bearing sleeve providing radial support and a
bearing collar providing axial support.
25. A tensioning device according to claim 1 wherein the spring
provided between the roller carrier and the receiving and mounting
housing is a flat spiral spring.
26. A tensioning device according to claim 4 wherein the spring
provided between the roller carrier and the receiving and mounting
housing is a flat spiral spring.
27. A tensioning device according to claim 10 wherein the spring
provided between the roller carrier and the receiving and mounting
housing is a flat spiral spring.
28. A tensioning device according to claim 19 wherein the spring
provided between the roller carrier and the receiving and mounting
housing is a flat spiral spring.
29. A tensioning device according to claim 22 wherein the spring
provided between the roller carrier and the receiving and mounting
housing is a flat spiral spring.
30. A tensioning device according to claim 1 wherein the spring
provided between the roller carrier and the receiving and mounting
housing is a helical spring.
31. A tensioning device according to claim 4 wherein the spring
provided between the roller carrier and the receiving and mounting
housing is a helical spring.
32. A tensioning device according to claim 10 wherein the spring
provided between the roller carrier and the receiving and mounting
housing is a helical spring.
33. A tensioning device according to claim 19 wherein the spring
provided between the roller carrier and the receiving and mounting
housing is a helical spring.
34. A tensioning device according to claim 22 wherein the spring
provided between the roller carrier and the receiving and mounting
housing is a helical spring.
35. A tensioning device according to claim 30 wherein the helical
spring, when subjected to tensile loads, also connects the roller
carrier to the receiving and mounting housing and axially fixes the
roller carrier, via the bearing, relative to the receiving and
mounting housing.
36. A tensioning device according to claim 31 wherein the helical
spring, when subjected to tensile loads, also connects the roller
carrier to the receiving and mounting housing and axially fixes the
roller carrier, via the bearing, relative to the receiving and
mounting housing.
37. A tensioning device according to claim 32 wherein the helical
spring, when subjected to tensile loads, also connects the roller
carrier to the receiving and mounting housing and axially fixes the
roller carrier, via the bearing, relative to the receiving and
mounting housing.
38. A tensioning device according to claim 33 wherein the helical
spring, when subjected to tensile loads, also connects the roller
carrier to the receiving and mounting housing and axially fixes the
roller carrier, via the bearing, relative to the receiving and
mounting housing.
39. A tensioning device according to claim 34 wherein the helical
spring, when subjected to tensile loads, also connects the roller
carrier to the receiving and mounting housing and axially fixes the
roller carrier, via the bearing, relative to the receiving and
mounting housing.
Description
TECHNICAL FIELD
[0001] The present invention relates to a tensioning device for a
traction means, such as a belt tensioning device.
BACKGROUND OF THE INVENTION
[0002] The invention relates to a tensioning device for traction
means, such as a belt tensioning device, having a receiving and
mounting housing, a roller carrier pivotably connected to the
receiving and mounting housing, a bearing which radially and
axially supports the roller carrier relative to the receiving and
mounting housing, a spring for applying the tensioning force, and a
damping device. The spring is arranged between the roller carrier
and the receiving and mounting housing and the damping device
comprises a damping bush. By friction, the damping device dampens
any movements between the roller carrier and the receiving and
mounting housing in such a way that the damping effect is greater
in the direction of an increasing tensioning force than in the
direction of a decreasing tensioning force.
[0003] In motor vehicles, the vehicle engine drives various
auxiliary units such as a generator, a water pump for vehicle
engines with fluid cooling, a pump for servo-power for motor
vehicles with steering assistance and a compressor for an
air-conditioning system. Such auxiliary units are driven by a main
belt pulley positioned on the crankshaft of the vehicle engine and
by an infinite driving belt which, on the one hand, moves via the
main belt pulley and, on the other hand, moves via auxiliary belt
pulleys arranged on the driveshafts of the auxiliary units. The
functional efficiency of the auxiliary units and the service life
of the driving belt greatly depend on the setting and maintaining
of a certain belt tension of the driving belt. To improve the
functional efficiency of the auxiliary units and to prolong the
service life of the driving belt, it is general practice to use a
spring-loaded belt tensioning device which, as a rule, comprises a
damping device, so that any slip and vibrations can be compensated
for or reduced.
[0004] It is mentioned above that the invention relates to a
tensioning device for traction means. Above, details are given of a
special tensioning device for traction means, i.e. a belt
tensioning device. Below, the tensioning device for traction means,
which is dealt with by the invention, will always be referred to
and described as a belt tensioning device. This does not alter the
fact that the described tensioning device for traction means can
also be used for other applications, i.e. not only as a belt
tensioning device.
[0005] The initially described basic design of belt tensioning
devices, i.e. comprising a receiving and mounting housing, having a
roller carrier which is pivotably connected to the receiving and
mounting housing, bearings which radially and axially support the
roller carrier relative to the receiving and mounting housing, a
spring which applies the tensioning force and is arranged between
the roller carrier and the receiving and tensioning housing, as
well as a damping device, is generally known and to that extent,
reference is made to the German publication documents 37 28 158; 41
24 636; 41 34 354; 43 36 467; 43 45 150; 44 27 683; 195 40 706 and
196 03 558, to the German patent specifications 43 00 178 and 43 25
424, to the European publication documents 0 294 919 and 0 858 563
as well as to the U.S. Pat. Nos. 4,698,049 and 4,472,162.
Substantial differences, in particular, refer to the damping
device.
[0006] In the case of the belt tensioning devices known from the
German publication documents 195 40 706 and 196 03 558 and from the
European publication document 0 858 563, the function of the
bearing and that of the damping device are combined in one
assembly. The assembly is a cone-type friction bearing which is
applied by a spring force and which, on the one hand, radially and
axially supports the roller carrier relative to the receiving and
mounting housing and, on the other hand, by way of friction,
dampens the movements between the roller carrier and the receiving
and mounting housing. The disadvantage of the prior art belt
tensioning devices is that, on the one hand, due to the unavoidable
wear of the cone-type friction bearing, the roller carrier moves
axially relative to the receiving and mounting housing and, on the
other hand, the damping effect in the direction of load
application, i.e. in the direction of an increasing tensioning
force, is identical to the damping effect in the direction of load
relief, i.e. in the direction of a decreasing tensioning force.
[0007] In the belt tensioning device known from the European
publication document 0 294 919, it has been possible to avoid the
two above-mentioned disadvantages which are inherent in the belt
tensioning devices known from the German publication documents 195
40 706 and 196 03 558 and from the European publication document 0
294 919. As the belt tensioning device known from the European
publication document 0 294 919 does not comprise a cone-type
friction bearing, the disadvantage relating to such a cone-type
friction bearing, i.e. that the roller carrier moves axially
relative to the receiving and mounting housing, has been avoided.
In the belt tensioning device known from the European publication
document 0 294 919, the damping device is designed in such a way
that the damping effect in the direction of the increasing
tensioning force is greater than in the direction of the decreasing
tensioning force.
[0008] As far as details are concerned, the damping device used in
the belt tensioning device according to the European publication
document 0 294 919 comprises a damping bush and a band which is
positioned around the damping bush, whose first end is rigidly
connected to the receiving and mounting housing and whose other end
is subjected to a spring force. The spring force for tensioning the
band is applied either by an additional helical spring on the
receiving and mounting housing or by the spring primarily serving
for applying the tensioning force. In the embodiment shown, it is a
coil spring in the form of a leg spring. The first variant is
disadvantageous in that there is a need for considerable additional
means, in particular, the additionally required helical spring. The
second variant is disadvantageous in that the design of the spring
which serves to apply the tensioning force also determines the
damping characteristics of the belt tensioning device. The degree
of freedom desirable for the damping characteristics is thus
missing.
SUMMARY OF THE INVENTION
[0009] It is, therefore, an object of the present invention to
simplify the design and the production technology of a belt
tensioning device in such a way that, above all, it can be produced
more cost-effectively than prior art belt tensioning devices,
without attendant disadvantages.
[0010] The inventive belt tensioning device achieves the
above-mentioned objective, and is initially and primarily
characterised by a flat band spring for applying the friction force
to the damping bush. The flat band spring, at its first end, is
secured in a rotationally fast way to the receiving and mounting
housing or at the roller carrier and, at its second end, is secured
to the damping bush.
[0011] The present invention provides a tensioning device for
attraction mechanism including a receiving and mounting housing, a
roller carrier pivotably connected to the mounting housing, a
bearing which radially supports the roller carrier relative to the
mounting housing, a spring between the roller carrier and the
mounting housing for applying a tensioning force, and a damping
device. The damping device includes a damping bush which, by
friction, dampens any movement between the roller carrier and the
mounting housing in such a way that damping is greater in the
direction of an increasing tension force than in the direction of
decreasing tension force. A flat band spring applies the friction
force to the damping bush. The flat band spring is secured, at a
first end, to the receiving and mounting housing in a rotationally
fast way, and at a second end to the damping bush in a rotationally
fast way.
[0012] In belt tensioning devices of the type generally referred to
herein, the damping effect which compensates for or reduces slip
and vibrations is achieved by friction which occurs in the case of
movements between the roller carrier and the receiving and mounting
housing. On the one hand, this requires concentrically extending
friction faces which correspond to one another, such friction faces
being the inner or outer cylindrical face of the damping bush, and
a corresponding friction face at the roller carrier or at the
receiving and mounting housing. On the other hand, there is
required, in the form of a normal force, a friction force between
the friction faces corresponding to one another.
[0013] In the belt tensioning device known from the European
publication document 0 294 919, the friction force serving for
friction purposes is generated by two elements, i.e. by the band
positioned around the damping bush and by a spring by means of
which the band positioned around the damping bush is tensioned. In
contrast, in the belt tensioning device in accordance with the
invention, the friction force serving for friction purposes is
generated by one single element, i.e. by the flat band spring which
either partially or wholly embraces the damping bush and which, is
secured to the receiving and mounting housing or to the roller
carrier and, also, to the damping bush. The flat band spring acts
on the damping bush like a clamp band, such as on an associated
hose end. That the flat band spring is secured to the receiving and
mounting housing or to the roller carrier on the one hand, and to
the damping bush, on the other hand, however, is important.
[0014] Because the belt tensioning device in accordance with the
invention comprises a flat band spring which is secured to the
receiving and mounting housing or to the roller carrier, and also
to the damping bush, the damping bush is substantially rotationally
fixed so that the movements between the roller carrier and the
receiving and mounting housing generate friction between the
friction faces associated with one another and thus cause a damping
effect.
[0015] With the inventive belt tensioning device, the damping bush
is substantially rotationally fixed, i.e. it is substantially
secured against rotating. In this regard, "substantially" indicates
that any movements between the roller carrier and the receiving and
mounting housing lead to minimum rotational movements of the
damping bush. Such minimum rotational movements of the damping bush
are due to the fact that the friction force between the mutually
corresponding friction faces leads to a torque acting on the
damping bush. As the damping bush is not actually fixed rigidly,
but is fixed resiliently by the flat band spring, the torque acting
in the damping bush also results in a rotational movement of the
damping bush. The minimal rotational movement of the damping bush
leads to a minimal change in the diameter of the flat band spring
which, either partially or fully, embraces the damping bush. As a
result, there occurs a change in the friction force originating
from the flat band spring, and thus also in the damping effect.
[0016] The above explanations now provide the wanted facility of
ensuring that the damping effect in the direction of load
application, i.e. in the direction of an increasing tensioning
force is greater than in the direction of load relief, i.e. in the
direction of a decreasing tensioning force, which, in fact, is not
desired.
[0017] As far as details are concerned, there exists a plurality of
possibilities of designing and further improving the belt
tensioning device in accordance with the invention. For this
purpose, reference is made to the description of a preferred
embodiment in connection with the drawings and to the appended
claims.
[0018] Other advantages and features of the invention will also
become apparent upon reading the following detailed description and
appended claims, and upon reference to the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] For a more complete understanding of this invention,
reference should now be made to the embodiments illustrated in
greater detail in the accompanying drawings and described below by
way of examples of the invention.
[0020] In the drawings:
[0021] FIG. 1 is a plan view of a preferred embodiment of an
inventive belt tensioning device.
[0022] FIG. 2 is a section through the belt tensioning device
according to FIG. 1 along line II-II.
[0023] FIG. 3 is a section through the belt tensioning device
according to FIG. 1 along line III-III.
[0024] FIG. 4 is a diagrammatic illustration regarding further
explanations in respect of the inventive belt tensioning device,
generally according to a section through the belt tensioning device
according to FIG. 2 along line IV-IV.
DETAILED DESCRIPTION OF THE INVENTION
[0025] While the present invention is described with respect to a
belt tensioning device, the present invention may be adapted and
utilized for tensioning other traction mechanisms. Thus, although
the following components are described for a constructed
embodiment, these specific components are included as examples and
are not meant to be limiting.
[0026] The Figures show a tensioning device for traction means,
namely a belt tensioning device. The belt tensioning device
comprises a receiving and mounting housing 1, a roller carrier 2
which is pivotably connected to the receiving and mounting housing
1, a bearing 3 which radially and axially supports the roller
carrier 2 relative to the receiving and mounting housing 1, a
spring which applies the tensioning force and is arranged between
the roller carrier 2 and the receiving and mounting housing 1,
which spring, in the embodiment shown, is a helical spring 4 in the
form of a leg spring, as well as a damping device 5.
[0027] As shown in FIG. 1, the receiving and mounting housing 1
shown in the embodiment is provided with two fixing lugs 6, 7. By
way of the mounting lugs 6, 7 and mounting screws (not shown), it
is possible to fix the receiving and mounting housing 1, and thus
the belt tensioning device as a whole, for example on the vehicle
engine (not shown). A tensioning pulley 8 is rotatably supported at
the roller carrier 2, preferably via a rolling contact bearing
which does not have to be described in detail. When mounted in the
inventive belt tensioning device, the tensioning pulley 8 acts on a
driving belt (not shown). By way of the tensioning pulley 8, the
driving belt (not illustrated) is provided with a certain belt
tension which is of particular significance for the functional
efficiency of auxiliary units driven by the driving belt and for
the service life of the driving belt. The damping device 5 also
provided in the inventive belt tensioning device, above all, serves
to compensate for, or reduce, slip and vibrations.
[0028] As shown in FIGS. 2, 3 and 4, the damping device 5 of the
inventive belt tensioning device comprises a damping bush 9 and a
flat band spring 10. By way of its first end 11, the flat band
spring 10 is connected to the receiving and mounting housing 1 in a
rotationally fast way, and by way of its second end 12, it is
secured to the damping bush 9 in a rotationally fast way.
[0029] In belt tensioning devices of the type generally referred to
here, i.e. also in belt tensioning devices in accordance with the
invention, the damping effect which compensates for, or reduces,
slip and vibrations, is achieved by friction occurring as a result
of movements between the roller carrier 2 and the receiving and
mounting housing 1. On the one hand, it is necessary to provide
concentrically extending friction faces which correspond to one
another. In the embodiment shown, the friction faces are the inner
cylindrical face 13 of the damping bush 9, and a corresponding
friction face 14 at the roller carrier 2. On the other hand, it is
necessary to provide a normal force in the form of a friction force
between a pair of friction faces, i.e. between the inner
cylindrical face 13 of the damping bush 9 and the corresponding
friction face 14 at the roller carrier 2.
[0030] For the inventive belt tensioning device it is important
that the friction force required for friction purposes is generated
by one single component, i.e. by the flat band spring 10 which
embraces the damping bush 9 either partially or wholly and which is
fixed to the receiving and mounting housing 1, and to the damping
bush 9. The flat band spring 10 acts on the damping bush 9 in the
same way in which, for example, a band clamp acts on an associated
hose end, and it is particularly important that the flat band
spring 10 is secured to the receiving and mounting housing 1 on the
one hand, and to the damping bush 9, on the other hand. Because the
belt tensioning device in accordance with the invention is provided
with a flat band spring 10 which is secured to the receiving and
mounting housing 1 and to the damping bush 9, the damping bush 9 is
substantially rotationally fixed, so that movements between the
roller carrier 2 and the receiving and mounting housing 1 generate
friction, and thus a damping effect, between the associated
friction faces, i.e. between the inner cylindrical face 13 of the
damping bush 9 and the corresponding friction face 14 at the roller
carrier 2.
[0031] In the inventive belt tensioning device, the damping bush 9
is substantially rotationally fixed, i.e. it is substantially
prevented from rotating. In actual fact, however, movements between
the roller carrier 2 and the receiving and mounting housing 1 lead
to minimum rotational movements of the damping bush 9. The minimum
rotational movements of the damping bush 9 are due to the fact that
the friction force between the friction faces corresponding to one
another. That is, between the inner cylindrical face 13 of the
damping bush 9 and the corresponding friction face 14 of the roller
carrier, a torque acts upon the damping bush 9. The damping bush 9
is not actually secured rigidly, but it is secured resiliently by
the flat band spring 10. In consequence, the torque acting on the
damping bush 9 also causes a rotational movement of the damping
bush 9. The effect of this minimal rotational movement of the
damping bush 9 is that the diameter of the flat band spring 10
which either partially or wholly embraces the damping bush 9,
undergoes a minimum change, which means that the friction force
resulting from the flat band spring 10 and thus the damping force
also changes. This provides the desired facility of ensuring that
the damping effect in the direction of load application, i.e. in
the direction of an increasing tensioning force, is greater than in
the direction of load relief, i.e. in the direction of a decreasing
tensioning force. For this purpose, the flat band spring 10 is
mounted in such a way that when the roller carrier 2 moves in the
direction of load application, i.e. in the direction of an
increasing tensioning force, the diameter of the flat band spring
10 embracing the damping bush 9 decreases by a minimum amount.
[0032] It follows from the above that it must be possible for the
damping bush 9 to change its diameter as a result of the friction
force acting thereon. This could be achieved by producing the
damping bush from a sufficiently resilient material. However, in a
preferred embodiment, this is achieved in that the damping bush 9
is slotted, i.e. in that it comprises a slot 15 suitable for
diameter reduction.
[0033] It forms part of the invention that the flat band spring
associated with the damping device 5, by way of its first end 11,
is connected to the receiving and mounting housing 1 (or to the
roller carrier 2) in a rotationally fast way and that, by way of
its second end 12, it is connected to the damping bush 9 in a
rotationally fast way. This can be achieved in different ways. The
flat band spring 10, by way of its first end 11, is preferably
form-fittingly fixed to the receiving and mounting housing 1. For
example, as shown in the embodiment, by way of its first end 11, it
is held in a fixing slot 16 provided at the receiving and mounting
housing 1. The foregoing with reference to fixing the flat band
spring 10 by way of its first end 11, also applies to fixing the
flat band spring 10 by way of its second end 12. Thus, the flat
band spring 10, by way of its second end 12, can be form-fittingly
secured to the damping bush 9. In particular, the flat band spring
10, by means of its second end 12, can be held in a fixing slot 17
provided at the damping bush 9. Alternatively, the flat band spring
10 by way of its second end 12 can be held in the slot 15 for
diameter-reduction in the damping bush 9.
[0034] As already mentioned in connection with the inventive belt
tensioning device, there is provided a bearing 3 which radially and
axially holds the roller carrier 2 relative to the receiving and
mounting housing 1. In the embodiment shown in the figures, the
bearing 3 radially and axially supporting the roller carrier 2
relative to the receiving and mounting housing 1 includes of a
bearing bush 18 connected to the roller carrier 2 and a bearing pin
19 connected to the receiving and mounting housing 1. The bearing
bush 18, in turn, includes of a bearing sleeve 20 serving to
provide radial support and a bearing collar 21 serving to provide
axial support. Other bearing arrangements are also contemplated as
would be understood by those of skill in the art.
[0035] In the belt tensioning device in accordance with the
invention, the spring serving to provide tensioning force between
the roller carrier 2 and the receiving and mounting housing 1 could
be provided in the form of a flat spiral spring. However, in the
embodiment shown, the spring required for applying the tensioning
force between the roller carrier 2 and the receiving and mounting
housing 1 is provided in the form of a helical spring 4 in the form
of a leg spring. In the embodiment shown, the helical spring 4,
which is subjected to tensile loads, also connects the roller
carrier 2 to the receiving and mounting housing 1 and axially fixes
the roller carrier 2 via the bearing 3 relative to the receiving
and mounting housing 1. The friction occurring in this design
between the bearing collar 21 of the bearing bush 18 and the
receiving and mounting housing 1, if a movement takes place between
the roller carrier 2 and the receiving and mounting housing 1, is
negligibly small relative to the friction which is deliberately
generated in the region of the damping device 5.
[0036] As far as the illustrated and described embodiment is
concerned, the damping bush 9 is secured via the flat band spring
10 to the receiving and mounting housing 1 in a rotationally fast
way. However, it is also possible to secure the damping bush 9 via
the flat band spring 10 to the roller carrier 2 in a rotationally
fast way.
[0037] Finally, it should be pointed out that with the illustrated
embodiment of an inventive belt tensioning device, the tensioning
bush 22 is provided with a tensioning pin 23. The tensioning bush
22 serves as a stop for delimiting the possible movement between
the roller carrier 2 and the receiving and mounting housing 1. The
tensioning pin 23 which can be inserted through the tensioning bush
22 can be used for mounting the inventive belt tensioning device in
the mounting position.
[0038] From the foregoing, it can be seen that there has been
brought to the art a new and improved tensioning device. While the
invention has been described in connection with one or more
embodiments, it should be understood that the invention is not
limited to those embodiments. Thus, the invention covers all
alternatives, modifications, and equivalents as may be included in
the spirit and scope of the appended claims.
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