.
`
`United States Patent [19]
`Speckhart
`
`lllllllllllllllllllllllllllIllllIllllllllllllllllllllllllllllllllllllllllll
`[11] Patent Number:
`5,295,411
`[45] Date of Patent:
`Mar. 22, 1994
`
`US00529541 1A
`
`54 TOR ION
`[
`] SYS'FEM AL VIBRATION ABSORBER
`
`FOREIGN PATENT DOCUMENTS
`
`[76] Inventor: Frank H. Speckhart, 3411 Kingston
`pike, Knoxville, Tenn, 37919
`
`.
`
`60-97444 7/1985 Japan ................................... .. 74/574
`6099346 7/1985 Japan . . . . .
`. . . .. 74/574
`1415040 8/1989 Japan ................... .. 74/574
`401962 4/ 1932 United Kingdom .
`74/574
`586180 3/1947 United Kingdom .
`74/573
`.
`2103335 7/1982 United Kingdom ................ .. 74/574
`[21] Appl‘ No" 80’757
`Primary Examiner-Vinh T. Luong
`[22] Filedi
`Jlm- 22, 1993
`[51] In C]
`‘ F 6F 5 0 F 6C 3 M Attorney, Agent, or Firm-Michael E. McKee
`t.
`.5 ........................ ..
`1
`1 /1 ;
`l
`/
`ABSTRACT
`[57]
`[52] US. Cl. ...................................... .. 74/574; 74/572;
`74/573 R; 74/603; 74/604 A system for absorbing torsional vibration in a shaft
`[58] Field of Search ................... .. 74/ 572, 573 R, 574,
`which is drivingly rotated about an axis and wherein the
`74/603, 604
`shaft is exposed to torsional disturbances which tend to
`cyclically increase and decrease the rotational speed of
`the shaft utilizes a body attachable to the shaft for rotat
`ing therewith as the shaft rotates about its axis of rota
`tion and cylindrical rolling elements positioned within
`Cavities disposed in the body. During OpBTBIlOIl of tilt?
`system, the torsional disturbances induce pendulum-like
`motion of the cylindrical elements within the cavities in
`a manner which absorbs torsional vibration of the shaft.
`The cylindrical elements, the cavities and the torsional
`disturbances are related to one another in accordance
`with an equation which optimizes performance of the
`system and circumvents time-consuming trial and error
`techniques during design of the system. The system is
`particularly well-suited for absorbing torsional vibra
`
`[56]
`
`References Cited
`us. PATENT DOCUMENTS
`_
`lsaaralfin ................................ ..
`{286364 4/1942 A; fwd "" “
`“ 74/604
`2’287’866 6/1942 crisvz? er '
`" 74/604
`2:306:959 12/1942 Knibbe
`74574
`2,346,972 4/1944 Kishiine __
`N 74/574
`2,361,710 10/1944 Salomon
`._ 74/574
`2,449,087 9/1948 Salomon
`74/574
`3,219,120 11/1965 Hooper
`74/573 R
`3,336,818 8/1957 Allen ----- --
`74/573 R
`g’fthz‘ze
`""" "
`
`' ' ' ' ' ‘ ' ' ' "
`‘ ' ‘ ' ' ' '
`mos .'
`3’97 ’
`74/573 RX
`,
`0,260 7/l976 Bruggisser et al.
`4075 909 2/1978 Deakin ................. .. 74/573 R
`
`tion in a shaft which is rotated about an axis in response
`.
`.
`.
`.
`‘° PW“ Pulses generated wl‘hm an “new” °°mb“S'
`
`. . . . . .. 74/604X
`4,569,316 2/1986 Suzuki . . . . .
`.... .. 74/573 R X
`4,594,9l7 6/1986 Ziegler
`5,095,786 3/1992 Bellinghausen et al. ....... .. 74/574 X
`
`"on 6118"“:
`
`20 Claims, 4 Drawing Sheets
`
`Valeo Exhibit 1012, pg. 1
`
`

`
`US. Patent
`
`Mar. 22, 1994
`
`Sheet 1 of 4
`
`5,295,411
`
`%
`
`20
`/
`
`'
`
`22
`
`/ 26 @L
`
`24
`
`FT'g. 1
`
`— -
`
`28
`
`‘7':
`26
`
`Valeo Exhibit 1012, pg. 2
`
`

`
`US. Patent
`
`Mar. 22, 1994
`
`Sheet 2 of 4
`
`5,295,411
`
`Valeo Exhibit 1012, pg. 3
`
`

`
`US. Patent
`
`Mar. 22, 1994
`
`Sheet 3 of 4
`
`5,295,411
`
`Valeo Exhibit 1012, pg. 4
`
`

`
`US. Patent
`
`Mar. 22, 1994
`
`Sheet 4 of 4
`
`5,295,411
`
`Valeo Exhibit 1012, pg. 5
`
`

`
`1
`
`TORSIONAL VIBRATION ABSORBER SYSTEM
`
`5,295,411
`2
`without the need for time-consuming trial and error
`techniques.
`Yet another object of the present invention is to pro
`vide such a system which is uncomplicated in construc
`tion and effective in operation.
`
`BACKGROUND OF THE INVENTION
`This invention relates generally to torsional vibration
`absorbers and relates, more particularly, to means for
`absorbing torsional vibrations and for reducing speed
`variations in a rotating shaft.
`Shafts which are drivingly rotated commonly experi
`ence torsional disturbances during rotation, and these
`disturbances induce torsional vibrations in the shaft. In
`an internal combustion engine, for example, the engine
`crankshaft is exposed to cyclic torsional disturbances
`which tend to accelerate the shaft (during the power
`stroke) and which tend to decelerate the shaft (during
`the compression stroke). As another example, in a multi
`blade grinding apparatus having rotating blades which
`are driven by a drive shaft, the drive shaft is exposed to
`cyclic torsional disturbances which tend to decelerate
`the shaft (upon impact of a blade with an object being
`ground) and tend to accelerate the shaft (upon recovery
`of the speed of the blade after impact).
`The type of torsional disturbances with which this
`invention is concerned are those which are substantially
`regularly-spaced throughout a single rotation of the
`shaft. In a multi-cylinder internal combustion engine,
`for example, these torsional disturbances are a conse
`quence of equally-spaced power pulses generated
`within the engine cylinders. For example, in an eight
`cylinder engine, there are generated four equally
`spaced power pulses, and thus four regularly-spaced
`disturbances for each revolution of the crankshaft. In a
`multi-blade grinding apparatus, e.g., a tree chopper,
`having shaft-driven blades which engage objects being
`ground at a predetermined number of equally-spaced
`intervals during a single revolution of the driving shaft,
`there are produced an equal number of regularly-spaced
`disturbances for each revolution of the shaft.
`With regard to engine-driven shafts, it is known that
`the torsional vibrations induced in rotating shafts can be
`40
`controlled, to a degree, with vibration absorber devices
`intended to oppose the forces which excite, and thus
`absorb, the vibrations. The operating principles of a
`vibration absorber are in contrast to those of a vibration
`damper which is intended to dissipate energy of the
`vibrations.
`One vibration absorber is described in US. Pat. No.
`2,346,972 as including a wheel, or auxiliary ?ywheel,
`which is attachable to the crankshaft of an engine and
`which is provided with a series of circular pockets that
`are regularly spaced about the center of the crankshaft.
`A cylindrical inertia member is positioned within each
`pocket so as to be free to move both radially and rota
`tively with respect to the wheel. During operation of
`the engine, the ?ring pulses of the engine rotate the
`55
`wheel with the crankshaft and induce oscillatory move
`ments in the inertia members which are intended to
`counteract the torsional crankshaft vibrations.
`It is an object of the present invention to provide a
`new and improved system for absorbing torsional vibra
`tion and for reducing speed variations in a rotating shaft
`exposed to disturbances of the aforedescribed class.
`Another object of the present invention is to provide
`such a system which absorbs torsional vibration and
`reduces speed variations in a rotating shaft at all shaft
`speeds.
`Still another object of the present invention is to
`provide such a system whose design can be optimized
`
`SUMMARY OF THE INVENTION
`This invention resides in a system for absorbing tor
`sional vibration in a shaft which is drivingly rotated
`about an axis and wherein the shaft is exposed to tor
`sional disturbances which tend to alternately increase
`and decrease the rotational speed of the shaft and
`wherein the disturbances are regularly spaced through
`out each revolution of the shaft.
`The system includes means defining at least one elon
`gated cavity for rotating with a rotating shaft as the
`shaft rotates about its axis of rotation, and the elongated
`cavity is arranged in such a relation to the shaft so that
`the longitudinal axis of the cavity is substantially paral
`lel to the axis of shaft rotation. The system also includes
`a rolling element positioned within the cavity so as to be
`free to roll forwardly and rearwardly with respect to
`the direction of rotation of the shaft along the interior
`wall of the cavity in a pendulum action in response to
`the torsional disturbances during shaft rotation. Each
`rolling element is related to the elongated cavity and to
`the torsional disturbances desired to be absorbed by the
`system in accordance with the equation:
`
`wherein N is within about il5% of the number of the
`torsional disturbances per revolution, r... is the radius of
`the rolling element, r; is the radius of gyration of the
`rolling element, r1 is the radius of the cavity, and r3 is
`the radial distance of the cavity from the axis of rotation
`of the shaft.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 is an elevational view illustrating schemati
`cally an internal combustion engine utilizing a torsional
`vibration absorber embodying features of the present
`invention.
`FIG. 2 is a perspective view of the vibration absorber
`depicted in FIG. 1.
`FIG. 3 is an side elevational view of the FIG. 2 ab
`sorber, as seen generally from the left in FIG. 2.
`FIG. 4 is a perspective view of the FIG. 2 absorber,
`shown exploded.
`FIG. 5 is an elevational view of selected components
`of the FIG. 2 absorber, when assembled and as seen
`generally from the right in FIG. 4.
`FIG. 6 is a view of a fragment of the components
`illustrated in FIG. 5.
`FIG. 7 is a front elevational view of another embodi
`ment of an absorber incorporating features of the pres
`ent invention.
`FIG. 8 is a front elevational view of still another
`embodiment of an absorber incorporating features of
`the present invention.
`FIG. 9 is a fragmentary perspective view of a rotat
`able shaft and an absorber system utilized with the shaft.
`FIG. 10 is a front elevational view of yet still another
`embodiment of an absorber incorporating features of
`the present invention.
`
`50
`
`60
`
`65
`
`Valeo Exhibit 1012, pg. 6
`
`

`
`3
`DETAILED DESCRIPTION OF THE
`ILLUSTRATED EMBODIMENTS
`Turning now to the drawings in greater detail, there
`is shown in FIG. 1 a system, generally indicated 22, for
`absorbing vibrations in a rotatable shaft 24 associated
`with an internal combustion engine 20. The shaft 24 is
`rotated about an axis of rotation 26 in response to the
`power pulses generated within the engine, and the tor
`sional vibrations induced in the shaft 24 are effected by
`the torsional disturbances created by the alternating
`power and compression strokes within the engine cylin
`ders. The rotatable shaft 24 may take the form of an
`engine crankshaft, a ?ywheel, a clutch, a torque con
`verter, or some other part which is rotatably driven by
`the crankshaft. Furthermore, the system 22 may be
`incorporated within the shaft 24 or mounted upon the
`shaft 24 so as to be disposed, for example, on the front
`or the rear of the engine block. Moreover, the engine 20
`with which the system 22 is used may be either a spark
`ignited or a diesel-powered engine.
`Although the depicted system 22 is described herein
`as being used in connection with a shaft 24 exposed to
`torsional disturbances induced by the alternating power
`and compression strokes within an engine 20, a system
`in accordance with the broader aspects of the invention
`can be used for absorbing torsional vibrations in other
`rotating shafts which are exposed to cyclic torsional
`disturbances during‘ rotation. In the interests of the
`present invention, cyclic torsional disturbances are tor
`sional disturbances which tend-to alternately increase
`and decrease the rotational speed of the shaft and
`wherein the disturbances are substantially regularly
`spaced throughout each revoultion of the shaft. Ac
`cordingly, the principles of the present invention can be
`variously applied. ~
`As will be apparent herein, each system embodiment
`described hereinafter involves cavity-de?ning means
`associated with a rotatable shaft for rotation with the
`shaft as the shaft rotates about its axis of rotation. The
`cavity-de?ning means includes at least one elongated
`cavity which is spaced from the axis of shaft rotation
`and oriented so that the longitudinal axis of each cavity
`is substantially parallel to the axis of shaft rotation.
`Positioned within each cavity is a rolling element
`which, during rotation of the shaft, is permitted to
`freely roll along at least a section of the interior wall of
`the cavity in an oscillatory notion, i.e., in a pendulum
`action, a the rotatable shaft tends to vibrate (torsion
`ally) in response to the torsional disturbances to which
`the shaft is exposed.
`It is a feature of each system embodiment that each
`rolling element is related to its corresponding elongated
`cavity and to the torsional disturbances desired to be
`absorbed in accordance with the equation:
`
`55
`
`5,295,411
`4
`tion of the shaft 24. The system 22 obtains its optimum
`vibration-absorbing performance while the ?ring pulses
`are substantially equally spaced as aforedescribed but
`absorbs an appreciable amount of torsional vibrations at
`all engine speeds. The depicted system 22 is affixed to
`the shaft 24 for rotation therewith and, for this purpose,
`the crankshaft 24 includes a keyway 28, as best shown in
`FIG. 2.
`.
`With reference to FIGS. 2-4, the system 22 includes
`cavity-de?ning means 25 including a substantially plate
`like wheel body 30 having a cylindrical outer periphery
`32, two opposite planar faces 34, 36 and a central open
`ing 38. Six circular recesses, or cavities 40, are de?ned
`in the face 36 of the body 30 so as to be regularly spaced
`about and located at an equal distance from the central
`opening 38. Each circular cavity 40 has cylindrical
`interior walls and a longitudinal axis which is oriented
`substantially parallel to the axis of rotation of the body
`30 (as the body 30 rotates with the crankshaft 24 about
`the axis 26). In addition, each cavity 40 has a radius
`which is equal to the radius of every other cavity in the
`body 30, and each cavity 40 has a planar bottom, or base
`42, which is substantially parallel to the body face 36. If
`desired, the body 33 may be provided with internally
`threaded apertures 37 (shown in FIG. 5) with which a
`secondary body, e.g., a flywheel or belt pulley, can be
`secured to the body 30 with bolts. In such an instance,
`the cavities 40 would be positioned about the center of
`the body 30 so as not to interfere with the apertures 37,
`and the number of cavities 40 provided in the body 30 is
`preferably equal to an integer multiple of the number of
`apertures 37.
`The system 22 also includes six cylindrical rolling
`elements 44 positioned within the cavities 40 wherein
`each element 44 is positioned within a corresponding
`cavity 40. In the depicted system 22, the radii of the
`elements 44 are equal and the radius of each element 44
`is slightly smaller than that of the cavity 40 within
`which the element 44 is positioned. As will be apparent
`herein, each element 44 is free to roll along the cylindri
`cal sidewalls of its corresponding cavity 40 in a pendu
`lum action during rotation of the wheel body 30 about
`the axis 26 and, in the depicted embodiment, has a
`length which is slightly shorter than the depth of its
`cavity 40.
`For purposes of maintaining the elements 44 within
`the cavities 40, the system 22 includes a circular plate 46
`releasably secured to the wheel body 30 adjacent the
`face 36. To this end, the plate 46 includes a series of
`apertures, or through-openings 48, extending between
`the opposite sides of the plate 46, and the wheel body 30
`includes a series, of internally-threaded apertures 50
`disposed across the face 36 and which are aligned with
`the through-openings 48 of the plate 46. Headed screws
`52 are inserted through the through-openings 48 and
`tightened within the apertures 50 to secure the plate 46
`against the face 36 of the wheel body 30 and thereby
`maintain the elements 44 within the cavities 40. Because
`the plate 46 is releasably secured to the wheel body 30
`with the screws 52, access can be had to the interiors of
`the cavities by removing the plate 46 from the wheel
`body 30.
`For purposes of mounting the wheel body 30 about
`the crankshaft 24, the system 22 includes a collar 54
`tightly positioned so as to be secured within the central
`opening 38 of the wheel body 30. As best shown in FIG.
`4, the collar 54 includes an outer cylindrical perphery
`
`wherein N is within about i 15% of the number of the
`torsional disturbances per revolution, rwis the radius of
`the rolling element, r; is the radius of gyration of the
`60
`rolling element, r1 is the radius of the cavity, and r3 is
`the radial distance of the cavity from the axis of rotation
`of the shaft.
`With reference still to FIG. 1, the engine 20 has cylin
`ders within which ?ring pulses are generated in a prede
`termined sequence. Moreover, for a substantally con
`stant engine speed, the ?ring pulses in the engine 20 are
`substantially equally spaced throughout a single revolu
`
`65
`
`Valeo Exhibit 1012, pg. 7
`
`

`
`20
`
`5,295,411
`5
`6
`shaft 24. For example, for an eight cylinder, four cycle
`56 sized to be received by the opening 38 in a press-?t
`engine, there are four ?ring pulses per revolution. This
`relationship therewith and a hollow interior 58 sized to
`closely receive the crankshaft 24 when inserted there
`means that the natural frequency of an element 44
`within its cavity 40 for this example is equal to four
`upon. A groove 60 is provided along the length of the
`times the rotational speed of the engine.
`interior 58 and cooperates with the groove 28 of the
`In practice, it may not be possible to design the com
`crankshaft 24 to provide a keyway for accepting a key
`ponents of the system so that the right side of the equa
`62 (FIG. 2) inserted therein. When the wheel body 30 is
`tion provided above equals the exact number of tor
`positioned upon the crankshaft 24 and the key 62 is
`accepted by the provided keyway, the wheel body 30 is
`sional disturbances per revolution of the shaft, but it is
`believed that acceptable performance of the system is
`affixed to the crankshaft 24 so that as the crankshaft 24
`achieved if the right side of the equation is within about
`is rotated in response to the ?ring pulses generated
`within the engine cylinders, the wheel body 30 is ro
`i 15% of the number of torsional disturbances per rev
`olution of the shaft. Hence, the term N on the left side
`tated as well.
`of the equation includes a permissible range of values
`As the crankshaft 24 is rotated in response to the
`?ring pulses generated within the engine cylinders, each
`above and below the exact number of the torsional
`disturbances per revolution of the shaft being addressed
`cylindrical element 44 oscillates within its correspond
`by the system design. For improved absorption of the
`ing cavity 40 as a centrifugal pendulum between, for
`torsional vibrations, the right side of the equation is
`example, the solid and phantom positions illustrated in
`within about i5% of the number of torsional disturb
`FIG. 6. In this connection, each power pulse generated
`within the engine 20 effects a small increase in engine,
`ances per revolution of the shaft.
`Computer studies have con?rmed that because of
`i.e., crankshaft, speed which, in turn, shifts each cylin
`nonlinearities and other effects, better performance is
`drical element 44 within its cavity 40 in the rotational
`achieved when the right side of the above-provided
`direction opposite the rotational direction of the wheel
`equation is slightly greater than the ideal value, i.e., the
`body 30 about the rotation axis 26. This rearward shift
`number of torsional disturbances per revolution being
`of the element 44 tends to reduce, and thereby lessen the
`addressed, than when the right side of the equation is
`vibratory effects of, this small increase in engine speed.
`Conversely, the compression stroke of each engine
`slightly less than the ideal value. Thus, if in practice, the
`system components cannot be designed so that the right
`cylinder effects a small decrease in engine, i.e., crank
`side of the equation is exactly equal to the number of
`shaft, speed which, in turn, shifts each cylindrical ele
`torsional disturbances per revolution of the shaft being
`ment 44 within its cavity 40 in the rotational direction
`corresponding to the rotational direction of the wheel
`addressed, it is preferable that the system components 1
`be designed so that the right side _of the equation be
`body 30 about the rotation axis 26. This forward shift of
`slightly greater than (as opposed to less than) the num
`the element 44 tends to reduce, and thereby lessen the
`vibratory effects of, this small decrease in engine speed.
`ber of torsional vibrations per revolution of the shaft.
`To increase the effectiveness of the absorber system
`Under some circumstances and by way of example,
`22 for controlling and reducing torsional vibrations, the
`each element 44 may roll forwardly and rearwardly
`outer diameter and the thickness of the wheel body 30
`along the cavity walls through an arc of up to about 40°
`of movement during operation of the system 22.
`should be as large as possible, or as large as is practical,
`for a given application. The cylindrical elements 40
`As each cylindrical element 44 oscillates within its
`corresponding cavity, it moves in rolling engagement,
`should preferably be constructed of a relatively dense
`without slip, along the interior wall of its cavity 40.
`material, such as steel. The effectiveness of the absorber
`Computer studies reveal that the minimum coefficient
`system 22 can be a strong function of the outer diameter
`of the wheel body. For each particular outer diameter
`of friction required between the engaging surfaces of
`of the body, there is an optimum number of cavities,
`the element and the cavity walls in order to ensure that
`cavity radius (r1), and the radius location of the cavity
`the element 44 rolls without slipping along the walls is
`relatively low. In practice, however, it is preferred that
`(r;). In addition, it is also preferable to locate the cavi
`ties as close together as is consistent with the strength
`at least one of the surfaces of the element 44 or the
`capability of the wheel body.
`cavity walls be appropriately coated, treated or ma
`For illustrative purposes, exemplary dimensions of
`chined to increase the surface-to-surface friction be
`the system 22 wherein N=4 and in accordance with the
`tween these parts to reduce any likelihood of slip. Such
`aforementioned equation are provided here as follows.
`surface-to-surface frictional characteristics may be ob
`The outer diameter of the wheel body 30 is about 6.125
`tained by providing each element 44 or the cavity walls
`inches, the diameter of each element 44 is about 1.210
`with a textured surface. Lubrication between the engag
`inches, the diameter of each cavity 40 is about 1.375
`ing surfaces is neither desired nor necessary. To reduce
`inches, and the radial distance (r3) of each cavity 40
`friction and noise which may be created by contact
`from the rotation axis 26 is about 1.980 inches.
`between the ends of the elements 44 and the ends of the
`The system 22 is advantageous in several respects. In
`cavities 40, a low friction material, such as brass, Teflon
`the ?rst instance, the system 22 has the potential for
`or urethane may be placed over the ends of the elements
`absorbing much more torsional vibration and reducing
`44 or inside the ends of the cavities 40.
`speed variation in the crankshaft 24 than could be had
`In accordance with the equation provided above and
`with vibration absorbers of the prior art. Of course, by
`in order for the system 22 to be as effective as possible,
`better controlling torsional vibration, the likelihood of a
`the ratio of the natural frequency of any element 44 in a
`cavity 40 to the engine speed should be equal to the
`crankshaft failure is reduced. Secondly, the system 22
`provides vibration absorption over the entire speed
`number of torsional disturbances, i.e., disturbance cy
`range of the engine. More speci?cally, the system 22 is
`cles, per revolution of the shaft desired to be absorbed.
`65
`With regard to the depicted system 22, the number of
`tuned, or designed, to absorb torsional vibrations for a
`predetermined number of power pulses per revolution,
`torsional disturbances corresponds to the number of
`?ring pulses of the engine per revolution of the crank
`and its design is not a function of engine speed. Thus,
`
`40
`
`45
`
`50
`
`Valeo Exhibit 1012, pg. 8
`
`

`
`15
`
`25
`
`5,295,411
`8
`7
`the cavities 96, 96 and are related to the cavities 96, 96
`the system 22 is effective at all engine speeds. Thirdly
`in accordance with the equation provided above so that
`and in contrast to vibration dampers which control
`the right side of the equation is about equal to the num
`damping by energy dissipation, the vibration absorbing
`ber of torsional disturbances of one frequency, e.g.,
`system 22 does not operate by dissipating energy.
`four, and elements 104, 104 are positioned within the
`In addition, the useful life of the system 22 is believed
`cavities 100, 100 and are related thereto in accordance
`to be very long. With no sliding contact between the
`with the equation so that the right side of the equation
`cylindrical elements and the cavity walls, little wear of
`is about equal to the number of torsional disturbances of
`the system components is expected. Furthermore and in
`the other frequency, e.g., ?ve.
`contrast to some vibration absorbers and dampers of the
`It follows from the foregoing description of system
`prior art, there is no ?uid to leak or elastomer to fail.
`92 that the number of torsional disturbances addressed
`Still further, the uncomplicated design of the system
`by each element 102 and its cavity is a predetermined
`22 enables it to be constructed with relatively small
`number, e.g., four or ?ve, of disturbances per revolution
`cost, which cost is believed to be cleary less than that of
`of a shaft, rather than the cumulative total number, e.g.,
`some classes of dampers constructed for damping tor
`nine, of disturbances per revolution of the shaft.
`sional vibrations.
`Further still, the arrangement, number, and size of the
`It will be understood that numerous modi?cations
`system cavities do not have to be symmetrical about the
`and substitutions can be had to the system embodiment
`rotation axis of the system body. Moreover, the location
`22 without departing from the spirit of the invention.
`For example, although the system 22 has been shown
`of the cavities do not need to be totally symmetrical nor
`and described as including six cavities 40 within which
`do all the holes have to be located at the same radial
`distance from the center of rotation. Each cavity and
`cylindrical elements 44 are positioned, a system in ac
`corresponding cylindrical element merely needs to sat
`cordance with the broader aspects of the present inven
`isfy the equation provided above as the cavity and ele
`tion may possess an alternative number of cavities. For
`ment address a predetermined number of torsional dis
`example, there is shown in FIG. 7 an alternative system
`64 having a wheel body 66 within which eight cavities
`turbances through a single revolution of a shaft.
`Accordingly, the aforedescribed embodiments are
`68 ore de?ned.
`Furthermore, there is shown in FIG. 8 another alter
`intended for the purpose of illustration and not as limita~
`native system 70 having a wheel body 72 within which
`tion.
`four cavities 74 are de?ned. Experimental test results
`I claim:
`performed with the system 70 (l) with and (2) without
`1. A system for absorbing torsional vibration in a
`shaft which is drivingly rotated about an axis and
`its elements 76 positioned therein showed that for an
`wherein the shaft is exposed to torsional disturbances
`average rotational speed of the body 72 of about 800 to
`810 rpm, the amplitude of ?uctuations in the rotational
`which tend to cyclically increase and decrease the rota
`tional speed of the shaft, the system comprising:
`speed of the body 72 with its elements 76 in place is less
`than about one-half of that of the body 72 without its
`means de?ning at least one elongated cavity for rotat
`elements in place.
`ing with a rotating shaft as the shaft rotates about
`its axis of shaft rotation, the elongated cavity ar
`Still further, although the aforedescribed system em
`bodiments have been shown and described as including
`ranged in such a relation to the shaft so that the
`longitudinal axis of the cavity is substantially paral
`wheel bodies of cylindrical con?guration, the system
`cavity-de?ning body may take an alternative form. For
`40
`lel with the axis of shaft rotation;
`a rolling element positioned within the one elongated
`example, there is shown in FIG. 9 a system embodiment
`80 which has been integrated within the body of an
`cavity so as to be free to roll forwardly and rear
`engine crankshaft 82. In the system 80, the cavity-de?n
`wardly with respect to the direction of rotation of
`the shaft along the interior wall of the one cavity in
`ing means is provided by a radial section, indicated 84,
`a pendulum action upon exposure of the shaft to
`of the crankshaft 82, and the radial section 84 de?nes a
`torsional disturbances during rotation; and
`recess 86 which opens out of one side of the section 84.
`A cylindrical element 88 is captured between the bot
`wherein the rolling element is related to the one elon
`gated cavity and to the torsional disturbances de
`tom of the recess 86 and a plate 90 affixed to the one side
`sired to be absorbed by the system in accordance
`of the section 84 so as to cover the opening of the recess
`with the equation:
`86.
`Yet still further, although the aforedescribed system
`embodiments have been shown and described as includ
`ing cylindrical cavities of equal size and including cylin
`drical elements of equal size, a system in accordance
`with the broader aspects of the invention may include
`differently-sized cavities and differently-sized elements.
`For example, there is shown in FIG. 10 a system 92‘
`which has been designed to absorb torsional vibration in
`a shaft which is exposed to cyclic torsional disturbances
`of one frequency, e.g., four disturbances per revolution
`of a shaft, and other cyclic torsional disturbances of
`another frequency, e. g. ?ve disturbances per revolution
`of the shaft. To this end, the system 92 includes a cavity
`de?ning body 94 within which is de?ned two cavities
`65
`96, 96 of one diameter and one radial distance from the
`shaft axis 98 and two additional cavities 100, 100 of
`another diameter and another radial distance from the
`shaft axis 98. Elements 102, 102 are positioned within
`
`wherein N is within about 115% of the number of
`torsional disturbances per revolution of the shaft,
`rivis the radius of the rolling element, r; is the radius
`of gyration of the rolling element, r] is the radius of
`the one cavity, and r; is the radial distance of the
`one cavity from the axis of rotation of the shaft.
`2. The system as de?ned in claim 1 wherein N is
`within at least about 15% of the number of torsional
`disturbances per revolution of the shaft desired to be
`absorbed.
`3. The system as de?ned in claim 1 wherein N is at
`least as great as the number of torsional disturbances per
`revolution of the shaft desired to be absorbed.
`4. The system as de?ned in claim 1 wherein there are
`at least two elongated cavities de?ned by the cavity
`
`30
`
`35
`
`45
`
`Valeo Exhibit 1012, pg. 9
`
`

`
`5
`
`25
`
`5,295,411
`10
`9
`in the shaft which are substantially regularly spaced
`de?ning means, a rolling element is positioned within
`throughout each revolution of the shaft, the system
`each cavity as aforesaid, and each rolling element is
`comprising:
`related to its corresponding cavity and to the torsional
`means associated with the rotating shaft of the engine
`disturbances desired to be absorbed by the system in
`for de?ning an elongated cavity which rotates with
`accordance with the aforesaid equation.
`the shaft about the axis of shaft rotation, the cavity
`5. The system as de?ned in claim 4 wherein the cavi
`being arranged in such a relation to the shaft that
`ties are regularly spaced about the axis of shaft rotation.
`the longitudinal axis of the cavity is substantially
`6. The system as de?ned in claim 1 wherein the cavi
`parallel with the axis of shaft rotation;
`ty-de?ning means is provided by a body which is secur
`rolling element positioned within the elongated
`able to the shaft with which the system is utilized.
`cavity so as to be free to roll forwardly and rear
`7. The system as de?ned in claim 6 where