Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
The present invention relates to an elastic coupling
for shafts,coupling having a ring of radial spokes, every second
one of the said spokes being connected to a hub element on a drive
shaft, while the remaining spokes are connected, or adapted to be
connected, to a hub element on a driven shaft. This coupling
also has rubber elements arranged between the spokes which trans-
fer peripheral forces, are filled with a damping medium,and are .
reslliently deformed if the said hub elements do not rotate in
the same direction.
Couplings of this kind are adapted to absorb and
resiliently equalize non-uniform torques as well as axial and
angular displacements of the driving and driven shafts of two
machines connected by the shaft coupling. In the case of a
coupling of this kind disclosed in German Patent 1 450 191, in-
dividual, prestressed rubber elements are vulcanized, between con- .
secutive spokes, to the surfaces thereof. These rubber elements
are solid, and the damping properties produced b~ hy~sterisis of
the rubber can provide adequate damping for the resonant vibra- . .
tions of the machines, in the peripheral direction, as long as
the forces creating these torsional vibrations do not exceed the .
damping forces which the rubber elements can provide. If the said
forces do exceed the damping forces, the amplitude o the vibra-
. tions can become large enough to produce unacceptably rough :
running, or even destroy the coupling or other parts of the shafts. .
It is the purpose of the inven-tion to eliminate the
above-mentioned disadvantage of the known coupling by providing
additional damping means. .
'l'his purpose is achieved, accordiny to the invention ~.
as herein claimed, in the provision of an elastic coupling for ~:
connecting a driving shaft and a driven shaft, essentially comprising:
a plurality of members adapted to be connected alternately with the
driv:ing and the driven shafts in such a manner as to be disposed
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outwardly about the axes of the shafts when so connected; elastic
means disposed between and in-terconnectiny the members for trans-
mitting peripheral forces, from the members connectable to the
driving shaf-t to the said members connectable to the driven shaft,~
and for elastically deforming upon application of torsion to the
respective members about the axis of the coupling; the elastic means
at least partially defining deformable cavities between the respec-
tive members which vary in volume upon elastic deformation o~ the
elastic means; a damping liquid in the cavities, and restricted
flow passage means between at least some of the cavities so as
to provide hydraulic damping of torsional vibra-tions in the coupling.
According to a preferred embodiment, the members are
disposed generally in a ring--like configuration and comprises
spoke-like elements, whereby alternately one spoke-like element is
connectable with the driving shaft and the next spoke-like element
is connectable with the driven shaft. The elastic means, in this
preferred embodiment, comprises rubber~like elements disposed
between spokes and pre~stressed in compression so as to transmit
substantial peripheral forces and to deform upon sufficient torsion
20 of the respective spoke-like elements about the axes of the shafts ;
to which they are connectable. In this embodiment, the rubber-
like elements are disposed on either side of at least some of the
spoke-like elements having variable volume cavities suah that -the
cavity on one side of the spoke-like element comprises a drive
cavity and the cavity on the other side of the spoke-like element
comprises a driven cavity. The said drive and driven cavities of
each of the at least some spoke-like elements are interconnected
Yia the restricted flow passage formed by the restricted flow
passage means.
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As a result of the resilent deformation of rubber
elements, due to torsional vibration o~ the coupling, the volumes
of the cavities in the rubber elements, which are preferably
filled with a fluid, are increased on one side of the spo]ce and
simultaneously reduced on the other side, This causes the fluid
to move back and forth between the cavities through the apertuEeS
in the spoke. If the parts of the coupling are of suitable shape
and size, the resistance to flow offered by the said apertures
can produce an adequate hydraulic damping effect, thus ensuring
that the machines run quietly and preventing any parts of the
machines from being destroyed by resonant vibrations.
If the coupling consists of generally similar circular
parts, all of the spokes, or only the spokes of one hub element
may thus be apertured. The configuration of the rubber elements
is preferably such that the peripheral forces of the coupling are
absorbed by compression or thrust forces in the rubber elements.
In this connection, and for longer life, it is desirable for the
rubber elements to be prestressed in the torque-free condition of
the coupling, to an extent such that, under all operating condi-
ZO tions, the forces in the rubber elements which transfer the peri~pheral forces undergo no change of sign.
The rubber elements and spokes may constitute an
- integral coupling ring vulcanized in one operation, if the rubber ;
elements have cavities which can be produced in a corresponding
process.
A coupling ring may consist of two half-coupling
rings adapted to be fitted together axially and provided with re-
cesses forming the cavities in the coupling. In order to achleve ; ~;
the above-mentioned prestressing of the rubber elements, a coupling i;;
ring rnade correspondingly larger may be reduced to the installed
~iameter, by suitable means, either before or during assembly of
the coupling. The rubber elements and spokes of a hub element may
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form a rubber-metal part, gaps being provided between the said
rubber elements into which the spokes of the other hub ele~ent
are inserted or insertable.
If a coupling is made of individually vulcanized
rubber-metal parts, the cavities of which are produced by easily
extruded tool parts, the rubber element may be held in prestress
between the spokes and this may be assisted by the use of an
adhesive. Uetal end plates may be vulcanized to the rubber
elernents, and these may be glued to the spokes or may be pre-
stressed to bear against the said spokes, with a rubber-film seal.
In this case, edges projecting from the end plates, and bent over
before or during assembly, may engage in grooves in the spokes,
thus forming the joint between the said end plates and spokes. The
end plates may be provided with apertures and may form the spokes,
in which the end plates of adjacent rubber elements may butt to-
gether, may be connected together, and may have means for attach-
ment to a hub element.
One preferred form of pressur-loaded rubber element is
a cylindrical part through which a cavity, running peripherally,
passçs. In this case, the walls of the rubber element, especially
in the vicinity of the cavity, may be reinforced with peripheral-
ly flexible inserts, for example helical springs, in order to
prevent the rubber element from buckling outwardly as a result of
peripheral or centrifugal forces. The latter may also be achieved
by the provision of one or more radial supporting walls vulcanized
to the rubber element. These may also form two separate cavities
in a rubber element, each of which may exchange fluid with a
cavity located on the other side of the adjacent spoke. If there
; i5 any danger of the rubber elements being pushed out too far by
centrifugal forces, this may be counteracted by means o supporting
plates vulcanized in position and connected together by tension
members or enclosed by supporting rings not in contact with the
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spokes. One or more rings enclosing the coupling may also serve
to hold the spokes in position, in which case the supporting
rings may be removed when the unit is complete or may remain as
a permanent component of the coupling.
If consideration is given to two rubber elements in
the form of pr~ssure-loaded circular parts, one of which bears
against one side of a spoke, while the other bears against the
other side of the spoke, then one of the rubber elements will be
shortened peripherally by a suitably directed peripheral force -
in the coupling, whereas the other rubber element is simultaneous-
ly lengthened. The reduction in volume thus produced in one rubber
element, which affects the amount of fluid exchanged, and thus the
damping forces available, may be partly eliminated by transverse
expansion of the rubber element in a manner which reduces the
damping effect, whereas the increase in volume produced in the
other rubber element may be partly eliminated by transverse con-
traction of the cavity. In order to be abLe to obtain maximum
fluid damping, it is desirable to provided means for equalizing
effects. For example, the cavities may be provided with a cons-
triction whereby the rubber element is increasingly restricted
as the pressure loading increases; or any expansion or contraction
of the cavity may be prevented by vulcanizing a helical spring,
as previously mentioned, into the wall of the cavity. Even the
radial supporting walls mentioned above have a weaking effect. -
Projections from the spokes entering into the cavities may be used
for mechanically limiting the approach of the spokes, or may in-
crease the compression ratio of the cavities in the event of
relative movement between the spokes of the two hub elements, if
the said cavities are filled with a compressible damping agent.
One preferred design of thrust-loaded rubber element is
a rubber disc adapted to be connected to an outer casing desi~ned
to be connected to a spoke of one hub element, and vulcanized to
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an inner casing designed to be connected to a spoke of the other
hub element, the sai~ rubber disc having parallel or wedge shaPed
end-faces. The said casing may have free end-faces-provide with
seals which, in the finished coupling, lie prestressed against
the spokes.
The spokes may be integral with a hub element or may be
connected to a hub element by suitable means, for example by weld-
ing. The spokes may be provided with sleeves or holes into which
the pins of a hub element may be inserted. In this case, if the
peripheral forces do not pass through the centres of the sleeves
or holes, and therefore have a lever arm in relation thereto,
precautions must be taken to prevent the spokes from rotating.
This may be achieved with peripheral rings or annular discs con-
nected to the spokes, for example by welding.
The damping medium is preferably introduced after the
coupling has been assembled, closable filling openings and vent
openings, if necessary, beiny provided for this purpose at suit-
.
able locations.
If all of the cavities in the rubber elements communi-
cate with each other, only one filling opening is needed. In the
serviceable coupling, the pressure of the damping medium may be
equal to, higher than, or lower than atmospheric pressure. A pres-
sure higher than atmospheric pressure is preferable, especially if
a gaseous damping medium is used. Only a small portion of the
hea* produced in the fluid by coupling vibration can escape to the
outside through the rubber material, since the latter is a poor
heat conductor. Instead, most of this heat must be dissipated
through the metal parts of the coupling in the vicinity of the
cavities, for example through the spokes or through any radial
supporting plates that may be present. These parts may be provlded
with enlarged surfaces releasing heat to the environment, and may
be designed in a manner such as to promote cooling in the vicinity
of the coupling in the manner of a blower.
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If rubber elements which absorb peripheral forces by
compressive stresses are traversed by cylindrical cavities running ~ :
peripherally, and are supported by end plates or end pieces
running approximately radially and connected to the spokes, agaist
displacement, especially against displacement by centrifugal
forces, there remain between the said end plates and end pieces,
unsupported areas of the rubber elements which are arched out- -
wardly by centrifugal force and must absorb the resulting additional
inherent stresses. Above a specific limit rotary speed these
rubber elements are no longer capable of withstanding the inherent
stresses produced by centrifugal force.
In order that the shaft coupling may also be used at
high speed, the arrangement may be such that annular rubber ele~
ments are inserted into apertures, running parallel with the axis
of the shaft coupling, in a coupling disc, the said elements
serving to accommodate drive pins inserted axially into the saicl
~` rubber elements and forming the spokes of one hub elemént, in
which case the cavities, filled with pressure medium, are formed
by opposing pockets in the said rubber elements and are respective-
ly~defined by the inner casings of the apertures in the coupling
disc.
The annular rubber elements may be connected directly
wlth a drive bolt or with a rigid inner sleeve, preferably adhesi-
vely, the said inner sleeve accommodating a drive pin. The rubber
-elements may be made oversize in relation to the holes in the
coupling disc and may be seated therein with compressive prestress,
or they may be adhesively attached to a rigid sleeve adapted to be
inserted into the said holes. The edges of the pockets in the rubber
~elements constituting the cavities may be provided with a sealing ~`
bead ensuring adequate sealing of the cavities in relation to the
internal surfaces of the holes in the coupling disc.
` In a first type of this shaft coupling, with a rubber '
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elements inserted into holes in the coupling disc, the walls of -
the coupling disc located between the holes may form the spokes
of the other hub element, in which case the coupling disc is to
be provided with suitable means of connection to the driving or
driven shaft. In a second type of this shaft coupling, the drive
pins may form alternately the spokes of one and the other hub
element, the sai~ coupling disc floating, in a manner known per
se, between the said hub elements. With a given number o~ similar
rubber elements in the same coupling disc, a shaft couplin~ of
the first type can transfer twice the torque transferred by a
shaft coupling of the second type. However,the rigidity (torque
to angle of rotation) of a shaft coupling of the first type is
; much greater than that of a shaft coupling of the second type. A
shaft coupling of the second type is therefore better able to
compensate for misalignment between:the driving and driven shafts.
i A floating coupling disc may be connected to the hub
elements in known fashion by additional means and ma~ be held
thereby, in order to prevent the coupling disc from coming loose
at high r.p.m. as a result of imbalance.
The apertures controlling the damping forces may be
located in the walls between the holes in the coupling disc and/or
in the rubber elements in the wall between the two pockets. In
the case of shaft couplings of the second type, which has a
floating coupling disc, openings between the pockets of each
rubber element are indispensable, whereas openings in the walls
between the holes in the coupling disc are unnecessary and in-
effective, since the cavities, separated by these walls, in two
adjacent rubber elements undergo volume changes in the same direc-
tion for reasons of symmetry. It is desirable to provide openings
in the said walls both in the coupllng disc and in the rubber
elements, in order to provide a through-connection between all
cavities, both for filling them with the damping medium and for
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vénting them. Suitable and, if necessary, closable channels may
also be provided elsewherc:in the coupling disc and rubber elements
for filling and venting.
A description of various embodiments of the invention
now follows having reference to the appended drawings, wherein:
Fig. 1 is a cross section of a coupling having two hub
elements provided with radial spokes and pressure-loaded rubber
elements in between;
Fig. 2 is a longitudinal section through the coupling of
Fig. l;
Fig.~3 is a cross-section through one of the rubber
elements of the coupling of Fig. 1, prior to assembly;
Fig. 4 is a cross-section of a coupling in which six
- rubber elements form with three spokes of a hub element, a rubber-
.
metal part with gaps between the rubber elements, after assembly;
Fig. 5 is a part-view of the rubber-metal part of Fig.
4 prio~r to assembly;
~Fig. 6 is a cross-section of a rubber-metal part of a
coupling ring consisting of three similar rubber-metal parts;
~ Fig. 7 shows a rubber-metal part according to Fig. 6
assembled to an adjacent rubber-metal part, in cross-section in
; the peripheral direction;
~ - Fig. 8 is a cross-section through a thrust-loaded
`;~ rubber element prior to assembly;
Fig. 9 is a cross-section through the rubber element -
~ according to Fig. 8 incorporated between two spokes;
.~ Fig. 10 is a cross-section of a shaft coupling of the
first type having six rubber elements inserted into bores in a
coupling disc and connected adhesively with drive pins;
Fig. 11 is a longitudinal section of the shaft coupling
according to Fig. 10;
Fig. 12 is a cross-section of a rubber element adapted
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to be inserted, adhesively connected, to an annular casing onto
bores in a coupling disc, in a longitudinal section conceived as
lying in the peripheral direction;
Fig. 13 shows the rubber element according to Fig. 12
in cross-section;
Fig. 14 shows a shaft coupling of the second type in
cross-section, in which the rubber elements inserted into the
holes in a coupling disc are connected adhesively to an inner
sleeve and an annular casing.
In the following description, it is to be understood
that a first hub element is connected to one machine white a
second hub element is connected to the other machine.
The coupling according to Figs. 1 and 2 comprises a
first hub element 1, provided with a securing flange 15 and having
four cranked spokes 11 to 14, and a second hub ele~Etent 2 provided
<: with a securing flange 25 and having four cranked spokes 21 to 24.
Spokes 11 to 14 lie between spokes 21 to 24 and are attached to
stub shaft 16 integral with flange 15 . Spokes 21 to 24, on the
other hand are attached to stub shaft 26 integral with flanged 25,
20 the above attachments being by welding. ~leld between successive
pairs of spokes 11 and 21, 21 and 12, etc. is one of eight rubber
elements 31 to 38 comprising cavities 41 to 48 and 41' to 48',
divlded by supporting walls 51 to 58 and filled with fluid. A5
shown in Fig. 2, rubber elements 31 to 38 have, in the torque-free
condition shown in the said figure, a square cross-section 38' with
rounded corners, and cavities 41 to 48 and 41' and 48' are of cir~
cular cross-section 48". Prior to assembly, rubi:er elements 31 to
38 are identical to rubber element 3G shown in Fi 7. 3 which forms,
with supporting disc 56 and end plates 59, 60, a vulcanized rubber-
3a metal part, the peripheral length of which is greater than thelength once the rubber element is assembled. The latter is provided
with cavities 46 and 46', the shape of which accordin~ly difEers
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from that of the cavities in Fig. 1. The outer faces of end
plates 59,60 have rubber films and protruding edges 63, 64 on all
sides. In the longitudinal direction, spokes 11 to 14 and 21 to
24 have grooves 71,72. In the radial direction, the same spokes
have grooves similar to groove 71, not shown, in which the suitably
bent edges 63,64 of end plates 59,60 engage in such a manner that
; the end plates 59,60 of the rubber elements 31 to 38 are pressed
firmly and closely against the end faces of the spokes 11 to 14
an~ 21 to 24 and are thus secured against displacement. Spokes
11 to 14 and 21 to 24 each have a choke aperture 91 to 98 consti-
tuting the apertures in the spokes within the meaning of claim 1.
Spoke 24 is provided with a closable feel opening 65, whence a
- duct 66 leads to choke aperture 98. Support plates 51 to 5~ may
be provided with apertures 66, the purpose of which is merely to
connect all of the cavities together so that they can be filled
with fluid from a single filler opening 65. Rubber eIement 34 may,
if required, have a helical spring 67 which is vulcanized in and
which reinforces the walls of cavities 44, 44'. The hub 23 may
have a freely movable valve element 68, the rise of which is res-
20 tricted, and may be provided with a choke aperture 96, which can -~
compensate for high-frequency vibrations of small amplitude with-
out any exchange of fluid between cavities 45' and 46, in order
to prevent thé transfer, from one machine to the other, of high-
frequency vibrations, especially acoustic vibrations. There is
shown, in rubber element 35, a possible constriction 69 and a
constriction 70 of the cavity 45 which is still further constricted
with increasing peripheral pressure loading.
When hub element 1 rotates in relation to hub element
2, assumed to be stationary, in a clockwise direction, spokes 11 t
12,13,14 move closer spokes 21,22t23,24 and, at the same time,
move away from spokes 24,21,22,23, respectively thus reducing the
volume of cavities 41 and 41', 4~ and 43', 45 and 45', and 47 and
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47', while increasing the volume of cavities 48 and 48', ~2 and 42', '
44 and 44', and 46 and 46'. This brings about a trans~er o~ fluid
between the cavities adjacent each spoke, through choke apertures
91 to 98, in the appropriate direction, for instance from cavity
41, through choke aperture 91, into cavity 48', with an over-
pressure building up in cavity 41 due to the flow resistance offer-
ed by the said choke aperture. For reasons of symmetry, the same
over-pressure builds up in cavity 41' which is separated from
cavity 41 by supporting wall 51, the said cavity 41' emptying into
10 cavity~ 42, and it is immaterial whether supporting wall 51 has an ~'
aperture 66 or not. The steps described above as taking place in ~,
cavities 41,48' and 41',42 also take place in all of the cavities.
They also take place in reverse direction if the hub element 1 ', '
'~ rotates anti-clockwise in relation to hub element 2.
In the coupling shown Fig. 4, there is a first hub '
element 101 consisting of a hub ring 117 provided with a bore 115
:: .
and a keyway 116, and of three spokes 111 to 113 extending radial-
ly from,the hub ring 117. '
Vulcanized to the lateral surfaces of spokes 111 to , ~ ,
113 are rubber elements 131, 132; 133,13~; and 135,136. Free end-
surfaces 131' to 136' bear firmly and closely, under compressive
: '
prestress, against the lateral faces o~ three wedge-shaped spokes
121 to 123 which have through passages 124 to 126 into which drive
pins of a second hub element, not shown, are inserted. Rubber
elements 131 to 136 comprise cavities 141 to 146 divided from each ~,
other by spokes 111 to 113. Spokes 121 to 123 are provided with ,~
choke apertures L91 to 193 which open into the respective adjacent ~'
cavities and control the damping forces. Spokes 121 to 123 are
also provided, on both sides, with projecting edges 151 to 156, '
; .. .
defining bones which receive the ends of rubber elements 131 to 136 ''
and secure them against displacement. A tension strip, not shown, , ,
which surrounds the coupling and which can be removed as soon as ' ~' -
the drive pins of the second hub element are inserted into bores
124 to 126, keeps spokes 121 to 123 in the position indicated.
Fig. 5 shows the shape of the rubber elements 131 to
132, and of the cavities 141 and 142, prior to assembly. It may
be seen that hub elements 101 and rubber elements 131 to 136,
according to Fig. 4, form, before the coupling is completed co-
herent rubber-metal parts having gaps 137 between successive
rubber elements.
The rubber-metal part illustrated in Fig. 6 comprises,
connected adhesively together, a box-shaped metal end part 259
formed with holes 275, a rubber element 231 having a cavity 241,
a spoke 251 forming a sleeve 254, a rubber element 232 having a
cavity 242, and a box-shaped metal end part 260 having holes 276.
End part 259 has side walls 258 which enclose the rubber element
231, and a bottom wall 257 the outer surface of which is formed
with a sealing lip 256. End part 260 has a bottom wall 261 vul-
canized to the rubber element 232; the surface of the said bottom
wall, facing the rubber element, being provided with a sealing lip
262 and outwardly-directed side walls 263~ End part 259 is smaller
than end part 260 and is adapted to be inserted into end part 260
of an adjacent rubber-metal part. An intermediate plate 264,
having a choke aperture 291, may be placed between bottom wall 257
and bottom wall 261.
As illustrated in Fig. 7, a drive pin 265, passing
through cavity 241, may be inserted through holes 275 and 276' and
may be secured by a nut 266, the said pin connecting end parts 259
and 260' together. Sealing lips 256 and 262' seal cavities 241
and 242' from the outside, drive pin 265 being sealed by beads
267,268 in the holes 275. Three of the rubber-metal parts accord-
ing to Fig. 6, assembled in this manner form a coupling ring. A
drive pin of a first three-armed hub element, not shown, may be
inserted into each sleeve 254 of the said rubber-metal parts, and
12-
three drive pins 265 may be fitted to a second hub element, not
shown. The pitch circles of sleeves 254 and of holes 275 and 276
of the rubber-metal part, shown uncompressed, are larger than the
corresponding pitch circles of the hub elements. In assemhling
the coupling rings to the hub elements, the diameter of the latter
may be reduced, for example by means of a tensioning strip, until
the said pitch circles coincide, whereupon the drive pins may be
inserted, thus providing permanent prestressing of rubber elements
231 and 232 of all three rubber-metal parts.
Shown in Fig. 8~ is a vulcanized rubber element 331
which consists of an outer metal sleeve 357, an inner metal sleeve
358, and a rubber ring 356 having in cross-section, the shape of
- a parallelogram and a through-cavity 341. Sleeve 357 has a rubber-
coated flange 359, while sleeve 358 has a rubber-coated flange
360 running parallel with flange 359.
In the assembled condition shown in Fig. 9, rubber
element 331, the flanges of which are still parallel, is clamped
between two wedge-shaped spokes 311, 321. Rubber ring 356 has now
assumed a rectangular cross-section Rubber element 331 lies close ;
to the lateral surfaces of spokes 311,321 and is prevented from
moving laterally by projectin~ edges 361,362 thereo. Spoke 321
~ is provided with a choke aperture 391 which connects cavity 3~1
; with the cavity in adjacent, mirror-image rubber element 332.
Spoke 331 has an eye 363 for the accommodation of the drive pin
of a first hub element, and spoke 321 has a bore 36~ for the ac-
commodation of a drive pin of a second hub element Spoke 311, a
second spoke 312, and all other spokes on the first hub element
are joined securely together by means of an annular member 365,
for example by welding. Spoke 321 and all other spokes on the
second hub element have no contact with annular disc 365 and are
joined securely together by means of an annular disc, not shown,
lying in front of the plane of the drawing.
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The shaft coupling according to Figs. 10 and 11 is
formed of a coupling disc 407 provided with six holes 408 into
which are inserted six rubber elements 401 to 406. Drive pins
410, connected adhesively and directly to the said rubber elements,
are secured to a flange 414 of a hub element 415 having a bore 413
for the insertion of a drive shaft, not shown. A hub element 416,
having a bore 418 for the accommodation of a driven shaft, is
connected, thrugh a flange 417, and by means of a drive pin 411
secured to the said flange, to coupling disc 407 through which it
passes. Wall 412 between the holes 408, in coupling disc 407,
form the spokes of hub element 416. A central bore 419 in coupling
disc 407 may also serve for the direct accommodation of the
driving o~ driven shaft, in which case the coupling disc is also
the hub element and a separate hub element 416 may be dispensed
with.
Rubber elements 401 to 406 may be oversize in relation
to holes 408, so that, when inserted therein, they are prestressed -~
; in compressionin relation to the surfaces of holes 408. The said
elements may also be connected adhesively to the surfaces of holes
408. As illustrated by rubber element 401, rubber elements 401 to
406 are provided, in the peripheral direction of coupling disc 407
and on both sides of drive pin 410, with pockets 421,422 separated
from each other by rubber webs 425,426. Pockets 421,422 are bound
- laterally by rubber walls 423,424. In this respect, Fig. 10 shows
the rubber elements 401 to 403 as taken along line I-I in Fig. 11,
passing through the pockets 421,422, while the rubber elements 404
to 406 are taken along line II-II in Fig. 11, passing through the
rubber wall 423. Peripheral forces are transferred, with resilient
deformation of rubber elements 401 to 406, substantially by normal
stresses in the viainity of rubber walls 423,424, by drive pins
410, to coupling disc 407. To a lesser extent, the thrust stresses
between rubber elements 401 to 406 and the surfaces of holes 408
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also contribute to the transfer of peripheral forces.
Reference numberals 421,422 identify pockets 421 and
422 as well as cavities 921 and 422 in rubber element 401, the
said cavities being separated by rubber webs 425,426, defined by
the surfaces of holes 408, and filled with a damping medium.
Apertures 427,428 in rubber webs 425,426 connect cavities 421,422.
A channel aperture 429 in wall 412 also joins cavity 421 with
cavity 422' in the next rubber element 402. Ducts 430,431 and
432, shown in dotted lines in Fig. 10, are used to fill and vent ~-
the cavities 421,422. In the event of torsional vibration of hub
element 415 in relation to hub element 416, cavities 421, 421' etc
of all rubber elements 401 to 406 are alternately reduced and ;~
increased in size, while cavities 422,422' of all ruber elements
401 to 406 are inversely increased and reduced in size, so that
exchange of damping fluid takes place between these cavities
against the flow resistance offered by respective apertures 427,
428, 429. The apertures may be of a size and shape such that
vibrations, especially those of large amplitude, are effectively
damped. Moreover, the said apertures may also be provided with
means for controlling the flow resistance as a function of flow
velocity or other factors.
The rubber element shown in Figs. 12 and 13 is a
., . " .. .
rubber-metal part and consists of an inner sleeve 440, an annular
casing 441, and an annular rubber part g44 adhesively secured
thereto. Opposing pockets 445,446 are recessed into annular casing
441 in the vicinity of rectangular incisions 442,443. The outer
edges of pockets 445,446 are defined by sealing beads 447,448
projecting past the outer periphery of casing 441, and are separat-
ed b~ rubber webs 449,450. A conical channel aperture 452, re-
inforced by means of a rigid tube 451, connects pockets 445 and
446 together.
In the case of the shaft coupling shown in Fig. 14,
' . ' .
a coupling disc 470 is provided with the same number and arrange-
ment of rubber elements as coupling disc 407 of Fig. 10. Bores
481 in this coupling disc 470 accommodate rubber elements 482
having pockets 494 of the type shown in the rubber elements of
Figs. 12 and 13, or a rubber element 483 having pockets 495 sub-
stantially similar to rubber element 482, but differing therefrom
in that it comprises not on~ annular casing 489, but two separate
annular casings 485,486, so that the reinforcement provided by
annular casing 484, in rubber element 482, is lacking. In rubber
elements 482, drive pins 482 are inserted from the right, while in
rubber elements 483, drive pins 488 are inserted from the left.
Parts 489 and 390 of drive pins 487 extending to the
right, are adapted to be connected to a hub element 496, shown in
dotted lines, of a driving shaft, for example. Parts 491, 492 of
drive pins 488, extending to the left, are adapted to be connected
to a hub element 497, shown in dotted lines, of the driven shaft.
Apertures 498,499 in rubber elements 482,483 control the damping
forces produced by changes in volume of the cavities formed by
pockets 494,495. Coupling disc 470 floats between hub elements
~0 496,497.
'
,
"
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