Note: Descriptions are shown in the official language in which they were submitted.
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FLEXIBLE TORSION COUPLING
The invention relates to a flexible torsion coupling for two
machine elements, wherein a pair of rings are respectively provided on
the machine elements, which rings surround each other at a radial
spacing and wherein a damping element of rubber and a radial bearing
are positioned in the gap resulting from the radial spacing to connect
the rings parallel to each other. Particularly, the invention relates
to a flexible torsion coupling for use in, for example, torsion
dampers of internal combustion engines.
Such a coupling is used in the torsion damper disclosed in German
Utility Model 89 12 387.5. The damping element and the radial bearing
are therein positioned side by side in axial direction. This
construction creates a coupling of a relatively large axial length.
It is an aspect of the invention to provide an improved flexible
torsion coupling of a shorter axial length.
Accordingly, the invention provides a flexible torsion coupling
for two machine elements. The coupling includes a pair of first and
second rings, which rings are respectively connected to the two
machine elements and radially spaced apart surround each other. A
damping element and a radial bearing are positioned in the radial gap
created by the radial spacing of the rings. The first ring has an
axially open, U-shaped cross-section and the space defined by the
U-shaped first ring is at least partly divided by a second ring into a
pair of first chambers, which at least partly surround each other in
radial direction. The radial bearing is positioned in one of the
first chambers and the damping element is positioned in the other of
the first chambers. The damping element and the radial bearing may be
positioned to overlap in an axial direction, which provides for a
relatively shorter axial length of a torsion coupling in accordance
with the invention.
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Nonetheless, a good supporting of the rings on each other is
guaranteed, which allows the transmission of radial forces and renders
the use of such a torsion coupling in connection with pulleys and
torsion dampers more suitable.
The damping element may connect two axially spaced apart opposing
surfaces of the two rings, which permits the use of a damping element
of relatively large dimensions and the transmission of large relative
mutual rotations of the rings.
In applications where harder spring characteristics are desired,
the damping element preferably connects two radially spaced apart
opposing surfaces of the two rings. In such an embodiment, the
damping element is preferably rotation- symmetrical and, thus,
especially well supported against deformations caused by centrifugal
forces.
During the intended application of a torsion coupling in
accordance with the invention, the radial bearing may be especially
well protected from axial forces, when the bearing and the damping
element are positioned in a common radial plane. This is also
advantageous with respect to a size reduction of the coupling, which
is desired for economic reasons.
Embodiments wherein the radial bearing is a slide bearing are
preferred for their advantageous, especially short radial length. On
the other hand, if sufficient space is available in radial direction,
the use of a deep-groove ball bearing is preferred. Deep-groove ball
bearings are available ready for installation and guarantee, in
addition to an especially good relative rotatability of the two rings,
a good guiding and support of the rings in radial direction.
The second ring may have an annular projection that is radially
spaced apart from and surrounds that leg of the U-shaped first ring,
which radially outwardly surrounds the second ring. The radial gap
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resulting from the radial spacing of the annular protrusion and the
first ring is at least partly divided by a third ring into a pair of
second chambers, which second chambers at least partially surround
each other in radial direction. A second radial bearing is preferably
positioned in one of the second chambers and a second damping element
is positioned in the other of the second chambers to relatively
rotatably and elastically support the third ring. All the damping
elements and radial bearings are preferably positioned in a common
radial plane whereby the radial bearings may alternate with the
damping elements in radial direction.
The last described embodiment may be generally termed a
"cascade-type" construction. This construction may be modified by the
addition of supplementary intermediate rings similar to the third ring
in the manner described above.
The invention will now be explained by way of example only and
with reference to the following drawings, wherein:
Fig. 1 shows a half axial cross-section of a flexible torsion
coupling, which is used in a torsion damper and wherein two rings are
connected by a damping element which interconnects axially spaced
apart surfaces of the rings;
Fig. 2 is a half axial cross-section of an embodiment similar to
the one shown in Figure 1, wherein the radial bearing is a slide
bearing;
Fig. 3 illustrates a half axial cross-section of an embodiment
similar to the one shown in Figure 2, wherein the damping element
connects radially spaced apart surfaces of the two rings; and
Fig. 4 shows a half axial cross-section of a cascade-type
embodiment of a flexible torsion coupling in accordance with the
invention.
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A preferred embodiment of a flexible torsion coupling in accordance with
the invention as shown in Figure 1 is integrated into a fly-wheel torsion damper, which is
affixed to an end of a crank-shaft 13 of an internal combustion engine (not illustrated) and
includes an inertia ring or fly-wheel ring 14 and a pulley 15.
The flexible torsion coupling generally includes a first ring 1, which has an
axially open U-shaped cross-section. The space defined by the U-shaped section is partially
divided by a second ring 2 into a pair of radially inner and outer first chambers 5 and 6,
whereby the outer chamber 6 partially surrounds the inner charnber 5. Second ring 2 is
rigidly connected with pulley 15. A radial bearing 4 is positioned in the radially inner first
chamber 5, which bearing is a deep-groove ball bearing and relatively rotatably supports
the second ring 2 on the radially inwardly located leg 20 of the U-shaped profile of the first
ring. Thus, the pulley 15 is also supported in radial direction and may therefore be used
for the take up of belt transmitted forces, since relative radial displacements of the pulley
15 in relation to shaft 13 are prevented by second ring 2 and radial bearing 4.
An annular`damping element 3 is positioned in second chamber 6. Damping
element 3 is made of rubber-elastic material and connects two axially spaced apart opposing
surfaces of the first and second rings 1,2. Damping element 3 axially connects first and
second rings 1 and 2. Ring portion 2a of second ring 2 is relatively non-rotatably
connected therewith. It will be readily apparent to the art skilled person that this
connection may be achieved by press-fitting or welding. The radially extending sections
of damping element 3 extending between the second ring 2 and the ring portion 2a provides
for an additional contact surface and, thus, improved fixation of the damping element.
Fly-wheel ring 14 is of L-shaped cross-section and has an axially extending leg 18, which
is radially spaced apart from and connected with first ring 1 by a fly-wheel damping
element or damping layer 19.
c ~
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The embodiment shown in Figure 2 is similar in construction to the one
described above. However, instead of the deep-groove ball bearing, a slide bearing is used
in ~is embodiment. The slide bearing includes a bearing sleeve 4.1, which is rigidly
affixed to the second ring 2 and relatively rotatably engages the inner surface of the radially
S outer axially extending leg 21 of the U-shaped first ring
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1. The space taken up by the coupling in radial direction is thereby
comparatively reduced.
The embodiment shown in Figure 3 is similar in construction to
the one described immediately above. However, in contrast to the
previous embodiment, wherein axially opposite surfaces are connected
by damping element 3, a damping element 3.1 relatively rotatably and
elastically connects radially opposite surfaces of the first and
second rings 1 and 2. The damping element 3.1, the slide bearing
sleeve 4.1 and the pulley 15 are positioned in a common radial plane.
Relative radial displacements of these parts of the coupling are
therefore counteracted during the intended uses of the coupling.
Figure 4 shows a schematic illustration of a coupling in
accordance with the invention having a cascade-type construction. In
this embodiment, as in all the above described embodiments, the outer
leg 21 of the U-shaped cross-section of the first ring 1 radially
outwardly surrounds the second ring 2. However, second ring 2 further
includes an annular protrusion 7, which is radially outwardly spaced
from and surrounds the outer axially extending leg 21 of the first
ring 1. The resulting radial gap between the annular protrusion 7 and
the outer leg 21 of the first ring 1 is at least partially separated
by a third ring 8 into a second pair of radially inner and outer
chambers 10,9, whereby second radially outer chamber 9 at least
partially surrounds second radially inner chamber 10. A second radial
bearing 11 is positioned in second outer chamber 9 and a second
damping element 12 for the rotatably elastic supporting of the third
ring 8 is positioned in the second inner chamber 10.
Thus, damping elements and deep-groove ball bearings alternate in
radial direction in this embodiment. This substantially prevents an
eccentric compensation movement of the fly-wheel ring 14 relative to
shaft 13 upon introduction of belt-transmitted forces. Furthermore,
it is possible to include supplementary U-shaped intermediate rings
such as third ring 8 and to affix additional fly-wheel rings 16,17 to
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second ring 2 and third ring 8 and to the intermediate rings. These
additional fly-wheel rings may also be used for the introduction of
belt-transmitted forces into the flexible torsion coupling.
