Note: Descriptions are shown in the official language in which they were submitted.
i~76~345
SPECIFICATI0~
This invention relates generally to improvements in
viscous torsional vibration dampers, and is more particularly
concerned with dampers of this type in which an inertia ring is
mounted on a radially extending combination supporting damper
disk flange plate and mounting hub.
As is well known in the art, numerous advantages have been
experienced with viscous torsional vibration dampers, that is
; dampers utilizing the phenomenon of resistance to shearing of -
a a thin layer of viscous damping medium such as silicone fLuid
- 10 between relatively moving opposed parallel working surfaces in partcorotative with a rotary member such as a crank shaft subject to
torsional vibrations and in part carried by an inertia mass relatively ;
, torsionally movable with respect to the rotary member to be damped.
One desirable form of such dampers comprises a disk-like flange
structure having a hub portion to be attached to the rotary member
to be damped and a radially extending body portion carrying a ring
shaped inertia member having a working chamber enclosing an
annular body portion of the disk flange structure, with surfaces
of the disk body and the inertia member in shear film spaced
relation having regard to the viscosity of the viscous damping
medium which is sealed within the chamber by means of elastic
tuning spring spacing and sealing rings at the radially inner side
of the working chamber.
According to several prior arrangements, of which U.S.
Patent No. 3,303,719 is representative, the sealing and spacing
rings are Located at juncture of the inertia member carrying
portion of the mounting disk and axially extending flanges on the
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disk between the carrying portion and the hub portion. Such
an arrangement affords little, if any, tuning advantage from
the elastic rings.
As is well disclosed in U.S. Patent No. 2,636,399,for
example, an objectionable torsional vibration may occur at some
speed within the normal operating speed range for the mass
elastic system being damped; and to overcome this it is desirable
to connect the damper inertia mass to the hub by means of rubber
or rubber-like tuning spring means in such a fashion that the
~; lO frequency of the spring and inertia mass is a certain percentage
- of the natural frequency of the entire mass elastic system, there-
- by providing a counteracting force which gives the damper hub and
inertia mass significantly more relative movement than they would
have without the t~ning spring. Since the amount of friction work
that can be done by the viscous damping elements and by the
elastic tuning spring means is a function of the relative amplitude,
dampers using the tuning spring means are capable of transforming
more torsional vibratory eDergy into heat energy and are thus
capable of reducing the torsional vibration amplitudes of the system
to lower levels. l~his desirable effect is contingent upon being able
to obtain the proper dimensions and location of the elastic spring
means. In ~he forms of the damper shovm in U.S. Patent No.
2, 636,399, the elastic tuning rings are enclosed within the working
chamber in which the inertia mass is housed.
A damper arràngement of the inertia ring carried on a
mounting disk type which can attain at least some tuning advantage
from the greater resistance to shear of elastic bodies as compared
~.~768~5
to viscous damping medium alon ~is disclosed in U.S. Patent
No. 3,410,369. However, a serious deficiency in that dis-
closure is the high cost o production attributable to the -
necessity for much expensive machining of the parts of the ;inertia mass of the damper.
It is, therefore, an important object of the present
invention to overcome the disadvantages, deficiencies, in- ;
efficiencies, shortcomings and problems presented by prior
constructions, and to provide new and improved tuned viscous
i 10 damper constructions which will efficiently meet tuning
`' requirements in a basically torsional viscous damper of the
$ kind having the inertia mass supported on mounting disk means.
, Another object of the invention is to provide a new
`1 and improved iuned torsional viscous damper in which the
structural relationships are such as to assure efficient tuning. ;
A further object of the invention is to provide a new
and improved means for assuring substantially accurate,
efficient, balanced tuning by means of elastic, i.e., rubber
` including elastomeric, tuning spring rings in torsional
; 20 viscous dampers.
Still another object of the invention is to provide
new and improved structural relationships in torsional
viscous vibration dampers of the kind in which an inertia
ring is supported on a combined damper disk and attaching
hub member.
In an embodiment of the invention, there is provided
in a tuned torsional viscous damper, a flat supporting disk having
a radially outwardly extending circular body and a radially inner
hub portion adapted to be secured to a rotary m~er such as a
.. ..
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1076~45 ;`
crankshaft subject to vibrations to be damped by the damper, a ring
shaped inertia mass having an inner diameter and a radially
. inward annular opening through said inner diameter and leadingfrom an annular working chamber into which said body extends
concentrically through said opening, a viscous damping medium in
said chamber, said inertia mass comprising a pair of complemen-
` tary stamped heavy gauge annular sheet metal inertia plates each
~ of which has a radially outer axially facing annular portion in
; parallel shear film spaced relation to said disk body having regard
J' 10 to the viscosity of the viscous damping medium, means at the
radially outer extremities of said radially outer annular portions
maintaining an accurate spaced relation between said radially
outer portions, means at said }adially outer extremities
securing said plates fixedly together, radially inner annular
axially facing portions of substa~tial width of said stamped inertia
plates substantially offset axially away from said disk body, annular
transversely angular integral offsetting bends connecting said
radially inner portions to said radially outer portions, whereby
said radially inner portions define concentric annular recesses of
substantially greater depth than said shear film spacing and
sealing rings substantially filling said recesses and extending
across said shear filrn spacing into face to-face engagement with
said disk body, and th~reby maintaining said shear film spaced
relation between said disk body and said radially outer stamped
inertia plate portions, said rings being bonded at their opposite
axial faces to respectively said radially inner plate portions and
to said disk body and sealing said inward opening against loss of
3768~5
viscous damping medium, and providing tuning spring coupling - '
between the inertia mass and the disk.
Other objects, features and advantages of the invention
will be readily apparent from the following description of
, 5 certain representative embodiments thereof, taken in con-
,~ junction with the accompanying drawings although variations '`'',
'~ and modifications may be effected without departing from the ~ ,
spirit and scope of the novel concepts embodied in the ',',
disclosure, and in which: ',
;, . -
ON THE DP~WINGS: -
, FIG. 1 is a vertical longitudinal sectional detail view -
showing a representative damper construction; --, ,
FIG. 2 is an exploded assembly view of the damper of ''
FIG. l;
FIG. 3 is an enlarged fragmentary detail view of the ,-~'
tuning spring ring area of the damper of FIG. l;
FIG. 4 is a vertical longitudinal sectional detail view ;
showing one preferred embodiment of the invention;
FIG. 5 is a fragmentary vertical longitudinal sectional '
detail view of a modification;
FIG. 6 shows another modification; and
FIG. 7 is a view similar to FIG. 4 and showing a further
modification.
' In the tlmed rubber viscous torsional vibration damper 25,
as shown in Fig. 1, a supporting disk member 27 may comprise a
' flat annular disk of suitable thickness having a radially inner
hub portion 28 provided with means such as bolt holes 29 to ;~
facilitate mo~nting of the disk in ~concentric corotational relation on a
rotary structure such as a crankshat. Extending,integrally radially out-
~'' ~
~O';~68~5
wardly relative to the hub portion 28 of the disk 27 is a circular
body portion 30 which is received within a radially inwardly
opening annular working chamber 31 defined within a ring shaped
inertia mass 32. Within the working chamber 31, the body
portion 30 has an axially facing working surface 33 in spaced
parallel relation to a working surface 34 of the înertia mass,
and an oppositely axially facing working surface 35 of the body is
in spaced parallel relation to a confronting axially facing working
surface 37 of the inertia mass. At its perimeter, the body 30
; lO may have an annular radially outwardly facing working surface 38
in parallel relation to an annular radially inwardly facing working
surface 39. The spacing between the various confronting working
surfaces is predetermined in respect to the viscosity of a viscous
damping medium substantially filling the chamber 31 tO result
in shear films of the medium between the parallel confronting
working surfaces, having regard to the viscosity of the damping
medium. Thereby relative parallel movement between the body 30
and the inertia mass 32 is resisted ~y the viscous damping medium
acting as a viscous coupling and any relative parallel torsional
movement causes laminar shearing of the viscous medium whereby
- energy is dissipated and vibrations are damped. The damping
medium may comprise a silicone fluid of suitable viscosity for the
intended purpose.
In a desirable construction, the inertia mass 32 comprises
a pair of substantially equal opposite complementary inertia ring
members 40 and 41 hav~ng at ~heir radially outer perimeters spacer
flanges 42 which extend into edge-to-edge abutment and substantially
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accurately define the spacing between the working surfaces 34
and 37 of the iner~ia mass. For securing the inertia ring
members 40 and 41 fixedly concentric, means comprising a
securing ring 43 extends about the outer perimeters of the joined
inertia rings, and the opposite margins of the ring 43 are bent
as by spinning or cramping from the original diameter shown in
dash outline in Fig. 1 into locking flanges 44 ont chamfered shoulder
s lrfaces 45 on the respective inertia rings, with suitable sealing
means locked by the flanges 44 into grooves 47 in the surfaces
45. This hermetically seals the radially outer perimeter of the
working chamber 31 defined within the inertia mass 32.
At its radially inner perimeter, the working chamber 31
is sealed by combination elastic tuning, spacing and sealing rings
48. To provide adequate mass in the rings 48 for tuning purposes
they are of substantial radial ex.tend and axial thickness and duro-
meter for their intended tuning function. To accommodate the
rings 48, each of the inertia members 40 and 41 is provided with
a groove 49 at the radially inner end of the respective working
surfaces 34 and 37. As will be noted, the grooves 49 are of
equal depth and width and as nearly as practicable perfectly con-
centric. At their radially outer limits, the grooves 49 are defined
by respective axially extending shoulder wall surfaces 5~ defining
with the radially outer sides of the rings 48 viscous damping medium
reservoir spaces communicating with the chamber 31. At their
radially inner sides, the grooves 49 are defined by radially out-
wardly facing respective shoulder wall surfaces 51 provided by ~ -
solid respective axially extending ring retaining and protective
~0768~
flanges 52 on the inertia ring members. By having the axially
extending shoulders 51 axially aligned, and the tuning rings 48
of substantially the same inside diameter as these shoulders
there is assured concentricity and optimum cooperative tuning
function of both of the tuning rings. It may be observed that in
implementation of their tuning and sealing spring function, the
elastic rings 48 are desirably on the order of five or six times
as wide as their thickness. To attain their spacing function, the
elastic rings 48 are of sufficiently equal greater thickness than
the depth of the grooves 49 so that the elastic rings project from
the grooves across the shear film spacing gaps between the
axially facing working surfaces on the body 30 and the inertia
rings 40 and 41, thereby maintaining substantially accurate shear
film spaced relation between the axial working surfaces. Desirable
protection is provided by the flanges 51 against contaminants and
dirt reaching and deteriorating or interfering with proper functioning
of the spring rings 48.
By bonding of the rings to the root surfaces within the
grooves 49 as well as to substantially equal areas of the body 30,
the elastic rings 48 effect thorough hermetic sealing of the working
chamber 31. Such bonding may be frictional by compressive
pressure against the elastic rings 48 clamped and squeezed to a
thinner, wider section between the inertia rings 40 and 41 and
the body 30; or the bonding may be effected by means of suitable
bonding or adhesive agent with or without compressive pressure
clamping pressure upon the elastomeric rings to attain a desired
tuning value. In any event, thP elastic rings 48 are maintained
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in thoroughly concentric, stabilized tuning relation to the body
30 and the inertia mass 32. As used herein, the term "elastic"
means a rubber or rubber-like elastomeric material possessing
the proper elasticity for the tunillg function of the rings 48. At
least on those surfaces exposed to the viscous damping medium
fluid, the rings 48 must be inert to such fluid.
In assembling the parts of the damper 25, as demonstrated
in Fig. 2, the preformed elastic rings 48 are mounted within
the grooves 49 about the shoulders 51 serving as alignment pilot
means, and in an uncompressed condition the rings 48 are prefer-
ably sufficiently thicker than the depths of the grooves 49, so that
when the rings are placed under compression between the inertia
disks 40 and 41, they will uniformly expand in the grooves toward
their radially outer sides but without filling the reservoir spaces.
In the uncompressed condition, ~he rings 48 are of substantially
differentially smaller diameter at their radially outer sides than
the diameter of the groove shoulders 50, and are substantially the
same diameter at their radially inner sides as the shoulders 51
of the grooves. There~y the radially inner shoulders 51 provide
satisEactory gauging or pilot surfaces to assure substantial concen-
tricity of the respective elastic rings 48 in the grooves faciliting
economical assembly of the damper.
Bonding of the elastic rings 48 in the assembly may be
simply functional, but a suitable bonding agent 53 (Fig. 3) may
secure therr~ to the root surfaces in the respective grooves 49, and
the areas of the body 30 to be engaged by the elastic rings 48 may
be coated with a suitable bonding agent 54. When the rings 48
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~L0768~5
are pressed against the body 30, a thoroughly bonded relationship
will be assured. By bonding the rings 48 at their axially facing
surfaces to the damper cornponents, but leaving the radially facing
edges of the rings 48 free with respect to the sur~aces of
shoulders 50 and unbonded relative to ~he surfaces of the shoulders
51 excellent tuned torsional damping is attained by means of the
elastic spring tuning rings without detrimental distortions at the
radial perimeters of the tuning rings. Bonding of the axial surfaces
of the rings 48 also assures thorough hermetic sealing of the
working chamber 31.
Assembly of the mechanical components of the damper is
completed by squeezing the inertia disks 40 and 41 together to
place the elastic rings 48 under compression and causing the
radially outer spacer flanges 42 to abut, sliding the securing ring
43 into position abou~ the perimeter OI the inertia ring assembly,
and bending the marginal retaining ~langes 44 as by spinning into
locking retaining posItion as shown in Fig. 1. The final step
in completing the damper comprises filling the working chamber
31 with viscous damping medium as by introducing the same through
a filling opening 55 which after filling is sealed by means of a
plug 57. It will be understood that one or more additional openings
or ports similar to the filling opening 55 may be provided for
evacuation of air from within the chamber 31 in the course of filling
the damper.
A damper 153 as shown in Fig. 4 is functionally similar
to the damper already described, but comprises an inertia ring mass
154 formed from complementary annular inertia members 155 and 156
10'76~5
which are adapted to be formed up from suitable heavy gauge steel
sheet metal or plate material by stamping. Between radially
outer annular portions 155a and 156a of the stamped plates, mem-
bers 155 and 156 is defined a working chamber 157 into which
extends a circular body portion 158 of a supporting damper disk
159. At their outer perimeters, the portions 155a and 156a are
maintained in accurately spaced relation by an annular radially
inwardly projecting spacer rib 160 on a retaining and sealing ring
161 which has annular marginal flanges 162 turned into retaining
engagement with oblique shoulders 163 on the portions 155a and
156a and into sealing relation to respectivP grooves 164 containing
a suitable sealing material. Substantially accurate shear film
spaced relation of the confronting working surfaces of the portions
` 155a and 156a and the body 158 as well as the spacer rib 160
within the working chamber 157 is maintained by elastic combination
tuning spring, spacing and sealing rings 165 seated in respective
concentric annular recesses in substantially the form of rabbet grooves
167 provided by the radially i~er portions 155b and 156b of the
members 1i5 and 156 and substantially offset axially away from the
disk body. The rings 165 are maintained in concentric alignment
at least during assembly of the parts by means of angularly turned ;
inner marginal flanges 168. Angular shoulders 169 cooperate with
the radially outer edges of the rings 165 to provide annular
reservoir spaces. The shoulders 169 are provided by annular
transversely angular integral of~setting bends connecting the radially
inner portions 155b and 156b to the radially outer portions 155a and
156a and the shoulder surfaces slope substantially obliquely radially
,. , .. : , . ...
1i~3'76845
outwardly toward the disk body 158. Although the flanges 168
may be turned to an oblique angle as shown in full outline, if
preferred the~ may be turned to substantially right angular relation
to the faces of the members 155 and 156 as shown in dash outline.
It will be understood, of course, that the elastic rings 165 will
~e suitably bonded at their axial faces to the respective confronting
axial surfaces of the associated damper components, i.e., the disk
body 158 and the inertia plate portions 155b and 156b.
In Fig. 5, the damper 153' is substantially the same as the
damper 153 of Fig. 4, but the inertia members 155' and 156' are
maintained in proper spaced relation by means of abutting turned
spacer ~langes 169 at their outer perimeters engaged by the ring
161' which in this instance does n~t have a spacer rib, but has
the marginal turned flanges 162' retainingly engaged with the
outer sides of the turned flanges 169 and in sealing engagement
with sealing material trapping grooves 164'. In addition to, or
instead OI, the sealing grooves 164' and the sealing material
therein, a sealing ring 1~0 may be interposed between the flanges
169 and the perimeter of the damper body 15B'. On the other
hand, the ring 170 may be merely in the form of a bearing ring.
In Fig. 6 another slight modi~ication is depicted wherein
the inertia members 155" and 156" terminate at their outer
perimeter in abutting spacer fLanges 169' which taper to a smaller
dimension than the corresponding flanges in Fig. 5, whereby the
retaining and sealing ring 161" is narrower, although in other
respects functionally similar to the corresponding ring 161' in ~;
Fig. 5. The sealing or bearing ring 170' conforms to the shape
- .. . : - ~. :-. ... .. .
1~'7684~
at the inner side of the flanges 169', but is similarly oriented
rela~ive to the damper disk body 158" as in respect to the
corresponding arrangement in Fig. 5.
A tuned torsional viscous damper 230, as shown in
Fig. 7, comprises a ring shaped inertia mass 231 which is
adapted to be formed from heavy gauge sheet steel stampings, ~ ~.
comprising an inertia plate member 232 and a complemenl:ary inertia ~:
plate member 233, wherein the inertia plate member 233 has an
axially extending radially outer flange 234 provided with a rabbet
shoulder 235 engaged by the radially outer edge of the inertia mem-
ber 232 and locked in place by means of a turned terminal locking :
flange 237 on the inertia memb~r flange 234, and which also locks -:
sealing material in a groove 238. A working chamber 239 derined
between the members 232 and 233 receives therein a circular
body 240 of a supporting disk 241, with the confronting radial and
axial working surfaces within th~e chamber 239 in shear film spaced
relation having regard to viscoæi.ty of viscous damping medium
loaded into the chamber. I'he body 240 may have one or more
axially extending fluid transfer ports 241 therethrough to facilitate ;
equalization of viscous damping medium on both sides of the body
240. Elastic tuning spring, spacing and sealing rings 242 are
engaged in coaxial annular recess grooves 243 in the radially
inner end portions of the inertia members 232 and 233 and ~acing
axially toward the body 240 adjacent to the radially inward opening
` 25 f~om the chamber 239. The. elastic rings 242 engage the inertia
mass members 232 and 233 in the recesses 243 and also engage with ~.
surfaces on the body 240 and are desirably bonded there~o at least
frictionatly, although a bonding agent may be employed if desired.
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~L076
Means at the radially inner sides of the grooves 243 to assure
concentricity and protective enclosure of the rings 242 comprise
retaining flanges 244 on the radially inner edges of the inertia
rmembers 232 and 233 and turned toward but in close clearance
relation to the body 2~0. At the radially outer sides of the grooves
243, shoulders 245 cooperate with the elastic rings 242 to provide
annular reservoir spaces. As will be observed, the shoulders 245
are inner surfaces of annular transversely angular integral
offsetting bends connecting radially outer portions of the plates
232 and 233 which are in parallel shear film spaced relation to
the disk body 240 and radially inner portions of the plates of
width substantially offset axially away from the disk body 240 and
defining the recesses 243, The elastic tuning spring, spacing and
sealing rings 242 substantially fill the recesses 243 and extend
across the shear film spacing into face-to-face engagement with
the disk body 240 and may be under compression similarly as the
elastic rings 165 in Fig. 4 and the elastic rings 48 in Fig. 1.
A distinct advantage of the stamped sheec metal plate
structures of the iner~ia ring masses in Figs. 4-7, is that machining
is reduced to a bare minimum. In Fig. 4, for example, only the
surfaces 163 need be machined, and in Figs. 5 and 6 only the
abutting surfaces of che flanges 16~ and 169', respectively, which
determine the spacing between the stamped inertia plates. In
Fig. 7 only the rabbet groove 235 need be machined.
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