WO2015189139A1

WO2015189139A1 - Adjustable torsional vibration damper system

Info

Publication number: WO2015189139A1
Application number: PCT/EP2015/062687
Authority: WO
Inventors: Adam OWENS
Original assignee: Jaguar Land Rover Limited
Priority date: 2014-06-12
Filing date: 2015-06-08
Publication date: 2015-12-17
Also published as: GB2527112B; GB2527112A; GB201410511D0; EP3155292A1

Abstract

The present disclosure relates to a torsional vibration damper system, optionally for incorporation into a dual-mass flywheel of a vehicle. The torsional vibration system comprises a primary mass, a secondary mass, and a primary damper means. The primary mass and secondary mass are rotatably coupled to one another such that the primary mass and secondary mass can rotate relative to one another. The primary damper means comprises a primary damper spring that is disposed between the primary mass and the secondary mass for damping torsional vibrations and additionally comprises a first coupling mechanism configured and arranged to adjust, in situ, a stiffness of the coupling between the primary mass and secondary mass.

Description

ADJUSTABLE TORSIONAL VIBRATION DAMPER SYSTEM

TECHNICAL FIELD

The present invention relates to a torsional vibration damper system, in particular but not exclusively to a dual-mass flywheel, and to a vehicle comprising the same. More particularly, but not exclusively, the invention relates to a torsional vibration damper system wherein an effective stiffness of a primary damper means coupling between primary and secondary masses is adjustable. Even more particularly, but not exclusively, the invention relates to a torsional vibration damper system having a secondary damper means wherein a frequency of torsional vibration absorbed or damped thereby is actively or passively adjustable.

Aspects of the invention relate to a torsional vibration damper system, to a dual-mass flywheel comprising a torsional vibration damper and to a vehicle. BACKGROUND

The combustion cycles of an internal combustion engine create torque fluctuations which cause torsional vibrations which are passed down the drive train. This results in noise and vibration, such as gear rattle. It is known to provide a dual-mass flywheel (DMF) to reduce torsional vibrations that an engine will normally transmit into the driveline and transmission of a vehicle. Dual-mass flywheels typically comprise two flywheels: a primary flywheel (also referred to as a primary mass) attached to the drive shaft (crank shaft) of the engine; and a secondary flywheel (also referred to as a secondary mass) attached to a variable torque transmitting means, such as a clutch, which can selectively couple to the transmission.

The primary and secondary flywheels are typically coupled together, for example by means of a damper, such that the primary and secondary flywheels can oscillate with respect to one another. Circumferentially arranged springs (primary dampers) are provided between the primary and secondary flywheels and transmit torque from the primary to the secondary flywheel as well as damping or attenuating the torsional vibration. The primary flywheel can vibrate with the crankshaft. Torque is transferred from the primary flywheel to the secondary flywheel by a flange secured to the secondary flywheel. The flange comprises wings disposed between the circumferentially arranged springs. Torsional vibrations or oscillations are damped by the primary damper springs to reduce the amount of vibration that is transferred to the secondary flywheel. The inertia/stiffness ratio between the primary and secondary flywheels of the damper is fixed, meaning that the natural frequency of the torsional vibrations damped by such arrangements is fixed. For example, the fixed frequency of the coupling between the primary and secondary flywheels is typically about 500rpm to about 800rpm. The specific frequencies and magnitudes of the modes of torsional vibration vary with engine speed and can vary in dependence upon other factors, and further refinement in the reduction of torsional vibrations is desirable. Furthermore, power sources for motor vehicles are developing: there is a trend for engine downsizing; cylinder de-activation (CDA) systems are contemplated; and novel combustion methods are being developed; and, as a result, torsional vibrations may be excited at different and varying frequencies. For example, in cylinder de-activation (CDA) systems, certain cylinders of the internal combustion engine are permitted to be de-activated and re-activated in dependence upon power requirements. In such vehicles the frequency modes of torsional vibration can vary significantly in dependence upon the number of active cylinders. In consideration of this, improved torsional vibration dampers are desired.

The present invention seeks to provide an improved torsional vibration damper for motor vehicles and in particular, but not exclusively, an improved dual-mass flywheel. The invention may have application outside of DMFs and indeed outside of motor vehicles; for example, the improved torsional vibration dampers of the present disclosure may be utilised in other vehicle systems such as torque converters and launch devices and in other engine powered devices, such as machinery, other vehicles and generators. As such the torsional vibrational dampers of the present disclosure are not limited to application in motor vehicles. SUMMARY OF THE INVENTION

Aspects of the invention provide a torsional vibration damper system, a dual-mass flywheel comprising a torsional vibration damper system, and a vehicle.

According to an aspect of the invention for which protection is sought, there is provided a torsional vibration damper system comprising: a primary mass, a secondary mass, and a primary damper means, the primary mass and secondary mass being rotatably coupled to one another such that the primary mass and secondary mass can rotate relative to one another, the primary damper means comprising a primary damper spring disposed between the primary mass and secondary mass for damping torsional vibrations and comprising a first coupling mechanism configured and arranged to adjust, in situ, a stiffness of the coupling between the primary mass and the secondary mass. The primary mass and secondary mass are coupled with one rotational degree of freedom. Optionally, the primary damper spring comprises one or more primary damper compression spring components. The primary damper spring may also be referred to as a primary damper spring set.

Optionally, the torsional vibration damper system comprises a friction device, which may comprise a washer that acts as a friction coupling device between the primary or secondary mass, the friction device provides damping which reduces resonant effects. Optionally, said first coupling mechanism comprises:

a first lever;

a first moveable fulcrum pin about which the first lever can pivot; and

a first actuation means for adjusting the position of the first moveable fulcrum pin relative to the first lever,

wherein the first lever is coupled with one rotational degree of freedom to the primary mass and wherein the first lever is coupled with one rotational degree of freedom to the secondary mass.

Optionally, a first node of the first lever is pivotally mounted to the primary mass and a second node of the first lever is coupled to said primary damper spring. The primary damper spring is constrained by and/or acts upon and/or is otherwise fixed to the secondary mass. The primary damper spring may comprise one or more primary damper compression spring components and optionally each end of each such primary damper compression spring component is constrained by and/or acts upon and/or is otherwise fixed to the secondary mass.

Optionally, the first lever comprises a first elongate slot; wherein the secondary mass comprises a second elongate slot and wherein movement of the first moveable fulcrum pin is restricted by said first and second elongate slots.

Optionally, the first coupling mechanism further comprises a first bottom pin, coupling the first lever to said primary damper spring.

Optionally, the first coupling mechanism further comprises a first bottom pin extending from the second node of the first lever by which the first lever is coupled to said primary damper spring. Optionally, the first actuation means causes the first moveable fulcrum pin to move toward the first or toward the second node of the first lever and in dependence upon a position of the first moveable fulcrum pin the ratio of the first lever is adjusted and in dependence upon said position of the first moveable fulcrum pin, the first lever increases the effective stiffness of the primary damper spring.

Optionally, the first actuation means is either passively and/or actively operated. Optionally, the first actuation means comprises a driver and a phaser plate, the phaser plate comprising a third elongate slot and the driver being coupled to the phaser plate for controllably rotating the phaser plate for moving the first moveable fulcrum pin, which thereby adjusts the effective length of the lever which in turn affects the primary damper spring and effectively adjusts the stiffness of the coupling between the primary mass and the secondary mass. The effective stiffness and/or the stiffness/travel ratio of the primary damper spring may be affected.

Optionally, the first fulcrum pin moves radially, the primary and secondary masses rotate and the driver is provided by any one or a combination of: a linear-to-rotary driver, a hydraulic mechanism, a cam mechanism, and an electric motor, and the first actuation means is therefore actively operated.

Additionally or alternatively, the driver comprises a return spring, wherein one end of the return spring is coupled to the first moveable fulcrum pin and wherein the other end of the return spring is affixed to the phaser plate and the first actuation means is therefore passively operated.

Optionally, the return spring is a non-linear spring and comprises at least one of: a variable rate axial spring component acting in a linear motion; a fixed rate axial spring component acting in a non-linear motion; a variable rate torsional spring, acting in a linear motion and a fixed rate torsional spring, acting in a non-linear motion.

Optionally, the driver comprises a return spring, one end of the return spring is coupled to the second moveable fulcrum pin and the other end of the return spring is affixed to the phaser plate and the first actuation means is therefore actively and passively operated. Optionally, the torsional damper further comprises a secondary damper means for further reducing torsional vibrations, the secondary damper means is actively or passively adjustable and is configured and arranged for further reducing torsional vibrations across a range of torsional vibration frequencies.

Optionally, said secondary damper means comprises an absorber mass and a second coupling mechanism.

Optionally, the absorber mass is provided as a single annular disc disposed about the primary and secondary masses.

Optionally, said second coupling mechanism comprises:

a second lever;

a second moveable fulcrum pin about which the second lever can pivot;

a secondary damper spring; and

a second actuation means for adjusting the position of the second moveable fulcrum pin relative to the second lever,

wherein the second lever is coupled with one rotational degree of freedom to the absorber mass and wherein the second lever is coupled with one rotational degree of freedom to the secondary damper spring.

Optionally, the secondary damper spring comprises one or more second damper compression spring components. The secondary damper spring may also be referred to as a secondary damper spring set. Optionally, a first node of the second lever is pivotally mounted to the absorber mass and a second node of the second lever is coupled to said secondary damper spring.

Optionally, the second lever comprises a fourth elongate slot; wherein the secondary mass comprises a fifth elongate slot and wherein movement of the second moveable fulcrum pin is restricted by said fourth and fifth elongate slots.

Optionally, said second damper means further comprises a second bottom pin extending from the second node of the second lever, by which second bottom pin the second lever is coupled to a spring component of said secondary damper spring. Optionally, the first bottom pin of the first damper means and the second bottom pin of the second damper means are offset from one another and the first bottom pin contacts a spring component of the primary damper spring and the second bottom pin contacts a different spring component of the secondary damper spring.

Optionally, the second actuation means causes the second moveable fulcrum pin to move between the first and second nodes of the second lever and in dependence upon a position of the second moveable fulcrum pin the effective length of the second lever is adjusted and in dependence upon said position of the second moveable fulcrum pin, a frequency of torsional vibration damped by movement of the absorber mass is adjusted. Optionally, the second actuation means is either passively or actively operated.

Optionally, the second actuation means comprises a driver and a phaser plate, the phaser plate comprising a sixth elongate slot and the driver being coupled to the phaser plate for controllably rotating the phaser plate and for moving the second moveable fulcrum pin, which thereby adjusts the effective length of the second lever which in turn affects the frequency of torsional vibration damped by movement of the absorber mass.

Optionally, the first fulcrum pin moves radially, the primary and secondary masses rotate and the driver is provided by any one or a combination of: a linear-to-rotary driver, a hydraulic mechanism, a cam mechanism, and an electric motor and the second actuation means is therefore actively operated.

Optionally, the driver comprises a return spring, wherein one end of the return spring is coupled to the second moveable fulcrum pin and wherein the other end of the return spring is affixed to the phaser plate and the second actuation means is therefore passively operated.

Optionally, the driver is provided by any one or a combination of: a linear-to-rotary driver, a hydraulic mechanism, a cam mechanism, and an electric motor and the driver comprises a return spring, wherein one end of the return spring is coupled to the second moveable fulcrum pin and wherein the other end of the return spring is affixed to the phaser plate and the second actuation means is therefore actively and passively operated. Optionally, the first actuation means of the first coupling mechanism and the second actuation means of the second coupling mechanism are provided by a shared actuation means comprising a single phaser plate and a shared drive means.

Optionally, the primary damper spring set comprises more than one spring component, the secondary damper spring set comprises more than one spring component, said spring components are circumferentially arranged and are each accommodated within an aperture within the secondary mass; and wherein the absorber mass is provided as an annular mass disposed circumferentially about the primary and secondary masses; and wherein the secondary mass comprises a number of elongate slots corresponding to the number of spring components of the primary and secondary damper spring sets.

Optionally, the first coupling mechanism comprises more than one first lever, more than one first moveable fulcrum pin and more than one first bottom pin; and wherein the second coupling mechanism comprises more than one second lever, more than one second moveable fulcrum pin and more than one second bottom pin.

Optionally, the torsional damper further comprises a secondary damper means for further reducing torsional vibrations, wherein the secondary damper means is actively or passively adjustable and is configured and arranged for further reducing torsional vibrations across a range of torsional vibration frequencies, wherein said secondary damper means comprises an absorber mass and a second coupling mechanism comprising:

a second lever;

an extension portion;

a secondary damper spring;

a second moveable fulcrum pin about which the second lever can pivot; and a second actuation means for adjusting the position of the second moveable fulcrum pin relative to the second lever,

wherein a first node of the second lever is pivotally mounted to the absorber mass, wherein a second node of the second lever is coupled to said secondary damper spring, and wherein the extension portion is affixed to the primary mass.

Optionally, the second lever comprises a fourth elongate slot; wherein the secondary mass comprises a fifth elongate slot and wherein movement of the second moveable fulcrum pin is restricted by said fourth and fifth elongate slots. Optionally, the second damper means comprises a second bottom pin extending from the second lever, by which second bottom pin the second lever is coupled to a spring component of said secondary damper spring. Optionally, the absorber mass is provided as a single annular disc disposed about the primary and secondary masses.

According to a further aspect of the invention, there is provided a dual mass flywheel incorporating a torsional vibration damper system according to any relevant preceding paragraph, wherein a primary flywheel is provided by said primary mass and a secondary flywheel is provided by said secondary mass.

Optionally, the dual-mass flywheel is for use in a motor vehicle. According to yet a further aspect of the invention there is provided a vehicle comprising the torsional vibration damper system according to any relevant preceding paragraph or comprising the dual-mass flywheel according to any relevant preceding paragraph.

As used herein the term "effective stiffness" may be used, but not exclusively, to refer to the combined stiffness of a spring (primary damper spring or secondary damper spring) and the associated first or second lever mechanism of the associated coupling mechanism at the point of action.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: FIGURE 1 is an illustration of a vehicle comprising an internal combustion engine and a dual-mass flywheel according to an embodiment of the invention;

FIGURE 2 is a schematic illustration of part of the dual-mass flywheel shown in Figure 1 having a primary flywheel coupled to a secondary flywheel by a variable stiffness coupling;

FIGURE 3 is a perspective view of part of the dual-mass flywheel according to the arrangement shown in Figure 2; FIGURE 4 is an exploded view of part of the dual-mass flywheel shown in Figure 3;

FIGURE 5 is a schematic illustration of part of a torsional vibration damper system according to another embodiment that may be embodied in a dual-mass flywheel such as that shown in Figure 1 ;

FIGURE 6 is a perspective illustration of a torsional vibration damper system according to Figure 5;

FIGURE 7 is an exploded view of the torsional vibration damper system according to Figure 6 showing (from left to right): part of a driver in the form of a helical raceway; an absorber mass; a phaser plate and other components of a second coupling mechanism; a secondary mass; a primary damper means; and a primary mass.

FIGURE 8 is a perspective view of the primary mass shown in Figure 7;

FIGURE 9 is a perspective view of a secondary mass and two spring components of a primary damper spring shown in Figure 7;

FIGURE 10 is a perspective view of a phaser plate, an absorber mass, part of a driver and part of a first coupling mechanism of the torsional vibration damper system shown in Figure

7;

FIGURE 1 1 is an exploded view of the phaser plate, part of the absorber mass and part of a driver (in the form of a helical raceway) of the torsional vibration damper system according to Figure 10; FIGURE 12 is a schematic illustration of a torsional vibration damper system according to another embodiment that may be embodied in a dual-mass flywheel such as that shown in Figure 1 , wherein the torsional vibration damper system additionally comprises a passively adjusted driver for an actuator that is a common (i.e. shared) actuator of a first coupling mechanism and a second coupling mechanism;

FIGURE 13 is a schematic cross-sectional illustration of the torsional vibration damper system according to the embodiment illustrated in Figure 12; FIGURE 14 is a schematic illustration of a torsional vibration damper system according to another embodiment that may be embodied in a dual-mass flywheel such as that shown in Figure 1 , wherein the torsional vibration damper system comprises a passively and actively adjusted driver for an actuator common to (i.e. shared by) a first and a second coupling mechanism;

FIGURE 15 is a schematic cross-sectional illustration of the torsional vibration damper system according to Figure 14; and

FIGURE 16 is a schematic cross-sectional illustration of the torsional vibration damper system according yet another embodiment of the disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

Detailed descriptions of specific embodiments of the torsional vibration damper systems, vehicles and methods of the present invention are disclosed herein. It will be understood that the disclosed embodiments are merely examples of the way in which certain aspects of the invention can be implemented and do not represent an exhaustive list of all of the ways the invention may be embodied. Indeed, it will be understood that the torsional vibration damper systems, vehicles and methods described herein may be embodied in various and alternative forms. The Figures are not necessarily to scale and some features may be exaggerated or minimised to show details of particular components. Well-known components, materials or methods are not necessarily described in great detail in order to avoid obscuring the present disclosure. Any specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the invention. In Figure 1 , a vehicle 10 is shown which comprises an internal combustion engine (ICE) 18 (schematically represented), comprising a cylinder deactivation (CDA) system (not shown) which permits the six cylinder ICE to be operated in a three-cylinder mode of operation. There is also shown a dual-mass flywheel (DMF) 19 which is connected to or forms part of a driveline 50 of the vehicle 10. The driveline 50 transfers torque from the ICE 18 to the drive wheels 'W of the vehicle 10 via a transmission (not shown). The dual-mass flywheel 19 comprises a primary mass 1 1 and a secondary mass 12 (see Figure 2). The primary mass 1 1 (also referred to herein as "primary flywheel", "primary side" and "primary") of the dual- mass flywheel 19 is mounted and rigidly fixed to a crankshaft 20 of the internal combustion engine 18 such that the primary mass 1 1 rotates with the crankshaft 20.

The secondary mass 12 (also referred to herein as "secondary flywheel", "secondary side" and "secondary") of the DMF 19 and the primary mass 1 1 are coupled one to the other, for example with a bearing, such that the secondary mass 12 and the primary mass 1 1 can rotate relative to one another.

The secondary mass 12 comprises a means (not shown) for supporting a variable torque transfer system, such as a clutch (not shown), for coupling and un-coupling a following unit in the vehicle driveline 50, such as the transmission, for selectively transferring torque to the drive wheels 'W of the vehicle 10.

Various frequency-specific modes of torsional vibration of the driveline system 50 can be excited by the internal combustion engine 18. The excitation frequency depends upon, for example, the speed of the ICE 18; and the number of active cylinders operating in the ICE 18. A torsional vibration damper system 24 (see Figure 3) is associated with the DMF 19. The torsional vibration damper system 24 is actively and/or passively adjusted so that the frequency of vibration that is attenuated or absorbed by the torsional vibration damper system 24 can be altered in accordance with, for example, an operational state of the ICE 18. An "operational state" of the ICE 18 may, for example, be defined by the speed (in rotations per minute (RPM)) of the ICE 18 and/or the number of cylinders active in the ICE 18. Transient driver inputs (tip-in/tip-out) and binary driver inputs (pushing a sport button, for instance) could also be used as a parameter for calibration of the variable frequency torsional vibration damper system 24.

Due to the provision, for example, of a CDA that can, in effect, change the engine from being a six-cylinder engine to a three-cylinder engine, the operational range of the torsional vibration damper system 24 may be large. To cover the various frequencies of vibration and their harmonics over a range of vehicle speeds, optionally, in the present embodiment, the torsional vibration damper system 24 can operate to damp frequencies from about 8Hz to about 400Hz. In other envisaged arrangements, the torsional vibration damper system is tuned or calibrated for near 100% vibration cancellation in the range about 10Hz to about 100Hz.

In Figure 2 a schematic view of a DMF 19 comprising a torsional vibration damper system 24 according to various embodiments of the disclosure, is shown. It can be seen that the primary mass 1 1 is coupled to the secondary mass 12 by a primary damper means 28 that has a variable stiffness. By introducing a variable stiffness, the frequency of torsional vibrations that are damped by the torsional vibration damper system 24 can be adjusted, in situ, and optionally, in dependence upon an operational status of the ICE 18.

In Figure 3 a perspective view of the torsional vibration damper system 24 of the DMF 19 is provided. In Figure 4 an exploded view of part of the torsional vibration damper system 24 of the DMF 19 is shown. It can be seen that the primary mass 1 1 and secondary mass 12 are rotatably coupled to one another such that the primary mass 1 1 and secondary mass 12 can rotate relative to one another. Additionally, the torsional vibration damper system 24 comprises a primary damper means 28. The primary damper means 28 comprises a primary damper spring 27 (see Figure 4) disposed between the primary mass 1 1 and the secondary mass 12 for damping torsional vibrations; and comprises a first coupling mechanism 81 that is configured and arranged to adjust, in situ, an effective stiffness of the primary damper spring 27 that is disposed between the primary mass 1 1 and the secondary mass 12. Referring to Figures 3 and 4, it can be seen that the primary mass 1 1 comprises a substantially planar and generally disc-like structure having an outer rim 31 , an inner face 1 1 b, an outer face and a central aperture 'C which is optionally circular in cross-section. The inner face 1 1 b of the primary mass 1 1 comprises an optionally integrally formed mounting pin 42.

The secondary mass 12 comprises a substantially planar and generally disc-like structure having a diameter that is optionally less than the diameter of the primary mass 1 1 such that the secondary mass 12 can be seated or accommodated, at least partially, within the outer rim 31 of the primary mass 1 1 and adjacent the inner face 1 1 b of the primary mass 1 1 . The secondary mass 12 comprises at least one aperture 35 for receiving a primary damper spring 27 (see Figure 4). In this way the primary damper spring 27 is constrained by, held within and/or affixed to the secondary mass 12. In other envisaged arrangements, the ends of the primary damper spring 27 may be fixedly connected to the secondary mass 12 such that the primary damper spring 27 is held in a position in which it can be further compressed but not further extended. The primary damper spring 27 in the present embodiment takes the form of a non-linear spring component 27, more specifically a compression spring 27. The first coupling mechanism 81 in the present embodiment is best viewed in Figure 4 and comprises a first lever 32 disposed between the primary and secondary masses 1 1 , 12. The first lever 32 has a first end 32a (also referred to first node 32a) and a second end 32b (also referred to as second node 32b) and comprises a first elongate slot 33 extending between the first and second ends 32a, 32b. The first end 32a of the first lever 32 is hooked onto the mounting pin 42 of the primary mass 1 1 . The first lever 32 is pivotally movable about the mounting pin 42 such that the first lever 32 can oscillate. A first bottom pin 36 is coupled to or mounted to the second end 32b of the first lever 32 and optionally rests in the elongate slot 33. The first bottom pin 36 can engage, mate, abut or otherwise contact the primary damper spring 27 for influencing (increasing) the effective stiffness of the primary damper spring 27.

In envisaged embodiments the elongate slot 33 does not extend substantially over the entire length of the first lever and the pins 42 and/or 36 are mounted using one or more separate holes at the end of the first lever such that the slot 33 extends only over a less substantially and more central area of the first lever to allow movement of the pivot pin 44.

In envisaged embodiments, the first lever may be coupled to the primary mass 1 1 at a first node that is not strictly positioned at the terminus of the first lever and as such the terms "first end" and first node" are synonymous and do not necessarily limit the position of the coupling to being at the terminating limit of the first lever. Similarly, in other envisaged embodiments, the first lever may be coupled to the first bottom pin 36 at a second node that is not strictly positioned at the other terminus of the first lever and as such the terms "second end" and second node" are synonymous and do not necessarily limit the position of the coupling to being at the other terminating limit of the first lever.

Whereas the primary damper spring 27 is shown as a single spring 27 with the first bottom pin 36 engaging part way along its length, in this and/or other embodiments, the primary damper spring may be provided by more than one spring, for example two springs, one at each side of the first bottom pin 36.

The first coupling mechanism 81 additionally comprises a restrictably moveable first fulcrum pin 44. The first fulcrum pin 44 is moveable within the first elongate slot 33 of the first lever 32. The position of the first fulcrum pin 44 within the first elongate slot 33 determines the effective length of the first lever 32 which in turn determines the range of movement of the first bottom pin 36 and therefore the extent to which its movement influences (increases) the effective stiffness of the primary damper spring 27.

To control movement of the first fulcrum pin 44, the secondary mass 12 comprises a second elongate slot 43 (also referred to as fulcrum pin slot 43). The first fulcrum pin 44 extends through the second elongate slot 43 and thereby freedom of movement of the first fulcrum pin 44 is restricted.

To adjust the position of the first fulcrum pin 44 a first actuation means is provided. The first actuation means causes the first moveable fulcrum pin 44 to move towards the first and second ends 32a, 32b of the first lever 32. In dependence upon a position of the first moveable fulcrum pin 44 the effective length of the first lever 32 is adjusted and in dependence upon said position of the first moveable fulcrum pin 44, the first lever 32 influences (increases) the effective stiffness of the primary damper spring 27 and thereby the stiffness of the coupling between the primary mass 1 1 and the secondary mass 12. In the presently illustrated arrangement, the first actuation means is a combination of an active (driven) actuation means and a passive actuation means. The combination of both an active and a passive actuation means is optional; however, beneficially, the presence of the passive actuation means may reduce the energy parasitic of the active actuation means. In the present arrangement, the passive actuation means is provided by a 'mass-spring' actuator in the form of a return spring 29 (the mass being the inherent mass of the first fulcrum pin 44) and the active (driven) actuation means is provided by a phaser plate 15 and a driver (not shown).

The phaser plate 15 is disposed adjacent to the secondary mass 12 and is optionally a generally disc-like construct that is rotationally moveable. The phaser plate 15 comprises a third elongate slot 53 which is non-radially angled, i.e. is non-zero angled relative to the second elongate slot 43 provided in the secondary mass 12. The first fulcrum pin 44 has a length sufficient such that it passes into the third elongate slot 53. Rotational movement of the phaser plate 15 (caused by the driver) relative to secondary mass 12 can therefore cause the first fulcrum pin 44 to move radially outward or radially inward i.e. cause the first fulcrum pin 44 to move along the second slot 43. The driver may be any suitable driver capable of effecting rotational movement of the phaser plate 15 and may, for example, comprise a hydraulic mechanism or an electrical motor. Since the torsional vibration frequency alters in proportion to engine speed, it is desirable to provide a drive means that can translate linear movement into a rotational movement so that the actuation means can be powered in proportion to changing frequency to simplify the control of the torsional vibration damper system 24. In this way the drive means can be operated in proportion to engine speed. A suitable linear to rotational movement drive means may comprise a helical race-way type system as described below, which may be hydraulically driven, electrically driven, driven by a cam mechanism or other suitable mechanism. In envisaged embodiments, the relative motion of primary, secondary and tertiary masses is used to accumulate energy through a power take-off mechanism, optionally a linear electric generator. The accumulated energy may then be used to actuate the fulcrum pins of the torsional vibration damper system 24.

A first end 29a of the return spring 29 is coupled to the first moveable fulcrum pin 44, optionally via a rotational joint, and a second end 29b of the return spring 29 is affixed to the phaser plate 15. The return spring 29 is an axial tension spring and, in effect, is a non-linear spring because it acts in a non-linear motion. The effect the return spring 29 has on the position of the first moveable fulcrum pin 44 is therefore at least substantially proportional to engine speed, and thus at least substantially proportional to the frequency of the torsional vibrations that the torsional vibration damper system 28 is seeking to damp. In other embodiments, it is envisaged that the second end 29b of the return spring 29 is not attached to the phaser plate, but rather is attached to the secondary mass 12 for example.

It will be appreciated that in Figure 4 only a segment of the torsional vibration damper system 24 is shown. It is envisaged that in some arrangements, the torsional vibration damper system 24 may include more than one primary damper spring component 27 and correspondingly, more than one first lever 32, pin 42, second elongate slot 43, first moveable fulcrum pin 44 and first bottom pin 36. In such an arrangement, the first coupling mechanism 81 may comprise a phaser plate 15 with a corresponding number of third elongate slots 53; and a corresponding number of return springs 29. It will be appreciated that in other embodiments a purely active actuation means is utilised or a purely passive actuation means is used and as such the provision of a phaser plate 15 with one or more third elongate slots 53 and a drive means therefor; and the non-linear return spring 29, are both optional. In envisaged arrangements, the effective stiffness of the return spring 29 may be adapted by refining the angle of third elongate slot 53 in the phaser plate. The third elongate slots 53 may not necessarily be straight in order to tune the lever ratio over a range of engine speeds.

The torsional vibration damper system 24 when assembled is shown in Figure 3. In use, in dependence upon engine speed and other vehicle parameters, the return spring 29 will act on the first moveable fulcrum pin 44 and the driver (which is optionally controlled by a control unit) will be operated in conjunction therewith to appropriately position the first moveable fulcrum pin 44 such that the frequency of torsional vibration damped by the torsional vibration damper system 24 can be adjusted to match the frequency of torsional vibrations being excited by current operating conditions of the engine 18. The provision of an adjustable primary damper means 28 allows the torsional vibration damper system 24 to comprise a relatively low-stiffness primary damper spring 27 and as such a significant range of frequencies of torsional vibration can be damped. In dependence upon the application, such a torsional vibration damper system 24 may not achieve total vibration cancellation. However, with such a system 24 having a variable stiffness coupling 28 between the primary mass 1 1 and the secondary mass 12, oscillations could be reduced to an acceptable level. The provision of a low-stiffness coupling 28 between the primary mass 1 1 and the secondary mass 12 may have disadvantageous effects when such a torsional vibration damper system is utilised in some vehicles. For example, 'drive-ability' issues may arise from having a flexible driveline, i.e. dull throttle response. Nevertheless, a torsional vibration damper system 24 of this sort, (i.e. having a variable stiffness coupling 28 between the primary mass 1 1 and secondary mass 12), may be advantageous in larger, smoother engines, such as eight cylinder V engine. This may be particularly so where a CDA feature is provided and the engine is operated in a four-cylinder mode (e.g. whilst cruising).

Referring now to Figures 5 to 16, there are shown additional embodiments of the torsional vibration damper systems of the present disclosure. In the additional illustrated embodiments, like numerals have, where possible, been used to denote like parts, albeit with the addition of the prefix "100" and "200" and so on to indicate that these features belong to the alternative embodiments respectively. To avoid unnecessary duplication of description, only the differences in the embodiments of Figures 5 to 16 will be described in further detail.

To further refine the manner in which the torsional vibration damper system can damp, absorb or reduce torsional vibrations, in other embodiments an additional absorber (tertiary mass) is provided, which is oscillated in opposition to torsional vibrations that remain (in spite of operation of the primary damper means). In Figure 5, a schematic representation of such a torsional vibration system 124 is shown, wherein a combination of both an attenuating adjustable primary damper means 128 between the primary mass 1 1 1 and the secondary mass 1 12; and an absorbing secondary damper means 126 between the secondary mass 1 12 and the tertiary (absorber) mass 1 13 are used. In such a system 124, the attenuating, adjustable, primary damper means 128 reduces torsional vibrations across a range of frequencies; and the absorbing, adjustable secondary damper means 126 absorbs torsional vibrations and is tuned to trim or cancel resonant peaks in the operating range.

In Figure 6, there is shown a perspective view of a torsional vibration damper system 124. In Figure 7 an exploded view of the same torsional vibration damper system 124, and in Figures 8 to 1 1 enlarged views of particular components, are provided. With reference to Figures 6 to 1 1 , it can be seen that in an embodiment of a torsional vibration damper system 124, there comprises four spring components 127a, 127b, 127c, 127d; and the secondary mass 1 12 comprises four apertures 135a, 135b, 135c, 135d, one for housing each of the spring components 127a, 127b, 127c, 127d. The four apertures 135a, 135b, 135c, 135d are dimensioned, shaped and positioned to accommodate the four damper spring components 127a, 127b, 127c, 127d. Optionally, because four damper springs 127a, 127b, 127c, 127d of similar size and stiffness are provided, they are evenly spaced and are disposed at 90° relative to one another.

Optionally, in the present arrangement, four fulcrum pin slots 143a, 143b, 143c, 143d are provided, one radially associated with each aperture 135a, 135b, 135c, 135d and arranged such that the four fulcrum pin slots 143a, 143b, 143c, 143d are evenly spaced, extend in a radial direction and are disposed at about 90° relative to one another.

The primary mass 1 1 1 is coupled to the secondary mass 1 12 via a first coupling mechanism which in this arrangement comprises two first levers 132' and 132"; two mounting pins 142a, 142b (see Figure 8) and two first fulcrum pins 144d, 144b, which are received in apertures 143d, 143b of the secondary mass 1 12 respectively. Two first bottom pins (not shown) connect the two first levers 132', 132" with two primary damper spring components 127d, 127b respectively.

The torsional vibration damper system 124 comprises a vibration absorber in the form of an absorber (tertiary) mass 1 13. The tertiary mass 1 13 comprises an annulus having a planar structure that has an inner diameter that is greater than an outer diameter of the primary mass 1 1 1 such that the tertiary mass 1 13 can be seated about and moved relative to the primary mass 1 1 1 and secondary mass 1 12.

Advantageously, a second coupling mechanism is provided for coupling the absorber mass 1 13 (tertiary mass 1 13) to the secondary mass 1 12. The inner face of the tertiary mass 1 13 comprises two, optionally integrally formed, mounting pins 171 a, 171 b. Optionally the mounting pins 171 a, 171 b are evenly spaced and disposed at 180° relative to one another.

Two second levers 172', 172" are hooked onto the mounting pins 171 a, 171 b provided on the tertiary mass 1 13. The second levers 172', 172" are each long enough to extend from a mounting pin 171 a, 171 b to an associated secondary damper spring component 127a, 127c housed in the associated aperture 135a, 135c provided on the secondary mass 1 12. Each second lever 172', 172" interacts, engages or otherwise co-operates with the associated secondary damper spring component 127a, 127c. As such each end (node) of each second lever 172', 172" is attached by a fixed pivot: the (radially) outer end is pivotally fixed to the tertiary mass 1 13 and the (radially) inner end is pivotally fixed to the secondary mass 1 12, albeit indirectly, via interaction with the secondary damper spring component 127a, 127c housed therein.

A restrictably moveable fulcrum pin 144a, 144c is located within a fourth elongate slot 133a, 133c provided within the second levers 172', 172". Each second lever 172', 172" can pivot about the restrictably moveable fulcrum pin 144a, 144c. Movement of each second restrictably moveable fulcrum pin 144a, 144c is confined to a linear path by means of two fifth elongate slots 143a, 143c provided within the secondary mass 1 12. A common active actuation means is provided for both the first and second coupling mechanisms. In other words, the first and second coupling mechanisms share or utilise the same actuation means. Optionally, the common actuation means comprises a phaser plate 1 15 having four elongate, angled slots 153a, 153b, 153c, 153d. Rotation of the phaser plate 1 15 actuates the two first fulcrum pins 144d, 144b and the two second fulcrum pins 144a, 144c, simultaneously and to the same degree (i.e. "in phase"). Rotation of the phaser plate 1 15 is optionally achieved by a linear-to-rotary drive mechanism which optionally comprises a helical race way 173/175 as shown (see Figure 10) and which may additionally comprise one or more bearings (not shown). Alternative means for effecting movement of the phaser plate 1 15 may be used.

It will be understood therefore that in dependence upon a frequency of torsional vibration to be damped, the common actuation means, which in this arrangement comprises the phaser plate 1 15 can be rotated to simultaneously adjust, in situ, the two first fulcrum pins 144d, 144b and the two second fulcrum pins 144a, 144c. The stiffness of the primary mass 1 1 1 to secondary mass 1 12 coupling is thereby increased in correspondence with the rate/frequency at which the tertiary mass 1 13 is oscillating about the secondary mass 1 12.

In yet a further envisaged embodiment, as depicted schematically in Figure 12, a further torsional vibration damper system 224 is shown that is very similar to the embodiment of Figures 5 to 1 1 , albeit additionally comprising a passive actuation means 229. Optionally, the passive actuation means 229 is coupled in part to the phaser plate 215 and in part to a second fulcrum pin 244c. The passive actuation means 229 is optionally in the form of a non-linear mass-spring actuator (return spring) for adjusting (returning) the position of the first and second fulcrum pins 244d, 244c passively. A cross-section of a portion of a torsional vibration damper system 224 is shown in Figure 13. In yet a further envisaged embodiment, as depicted schematically in Figure 14, the first and second coupling mechanisms are differently arranged to provide a "shared" connection between the tertiary absorber mass 313 and the primary mass 31 1 , which has the effect of adjusting the stiffness of the coupling between the primary mass 31 1 and secondary mass 312 such that the torsional vibration damper system 324 can vary its frequency response in dependence upon the frequency of torsional vibrational modes that are required to be damped.

Such an arrangement may be more easily packaged, simpler to manufacture and more cost effective. In this arrangement, the first coupling mechanism is simpler and does not require a separate first lever for the primary mass 31 1 to secondary mass 312 connection, nor a first fulcrum pin, first bottom pin or an associated second elongate slot in the secondary mass 312. These components of the first coupling mechanism are not required and instead, the primary mass 31 1 is coupled to the secondary mass 312 via a first coupling mechanism that comprises a typical "fixed-stiffness" connection 327d (which allows the primary and secondary masses 31 1 , 312 to move rotationally relative to one another).

In this embodiment, the second coupling mechanism comprises: a second "extended lever" 382/382' (comprising a second lever 382 and second lever extension portion 382'); a second fulcrum pin 344; and a third elongate slot 343. Variation of the stiffness of the primary mass 31 1 to the secondary mass 312 coupling is achieved by means of a direct connection between the second extended lever 382/382' and the primary mass 31 1 . As can be seen in Figure 15, a first end (node) of the second lever 382 is coupled (optionally via a mounting pin 371 and a slot in the second lever 382) to the absorber mass 313. The second fulcrum pin 344 is moveable (as already described) to allow the effective length (or ratio) of the second lever 382 to be adjusted. A second bottom pin 336 projects from the second lever 382 and interacts with a secondary damper spring component 327c.

The extension portion 382' of the second extended lever 382/382' is rigidly and non- moveably affixed to or integrally formed with the second lever 382 of the second extended lever 382/382' and is coupled to the primary mass 31 1 (optionally by passing through a bore or aperture in the secondary mass 312 as shown in cross-section in Figure 15).

As with earlier embodiments, the second fulcrum pin 344 is moveable to adjust the fulcrum position about which the extended second lever 382/382' pivots, thus adjusting the frequency with which the absorber mass 313 can oscillate. As such, with increasing frequency of torsional vibration (i.e. with increasing engine speed), the second fulcrum 344 is moved radially outward (i.e. towards the absorber mass 313 (also referred to as tertiary mass 313) as depicted in Figure 15). The frequency with which the tertiary mass 313 can oscillate is thereby increased and additionally and in proportion, the effective stiffness of the connection between the primary mass 31 1 and secondary mass 312 is increased, thus adjusting the frequency of torsional vibration that is damped by the primary damper means 327d and secondary damper means 327c.

Movement of the second fulcrum pin 344 is optionally actuated actively and passively by a phaser plate 315 and return spring 329 by operation as already described. In this way, the coupling stiffness of both the first and second coupling mechanisms is linearly dependent on engine speed. Other suitable mechanisms for active and/or passive actuation means may be used. A cross-section of a portion of a torsional vibration damper system 324 is shown in Figure 15, albeit with the phaser 315 and return spring 329 omitted for clarity. It can be seen that the fixed rate primary damper spring 327d is disposed between the primary and secondary masses 31 1 , 312 and provides a fixed stiffness connection. The effective stiffness of this connection can be additionally varied by actuation of the second fulcrum pin 344.

In yet a further envisaged embodiment, as depicted schematically in Figure 16, it is envisaged that only a passive actuation means may be provided in a torsional vibration damper system 424 having optionally separate first and second coupling mechanisms. The passive actuation means is provided by a non-linear spring-mass 429 which operates as described above. It can be appreciated that various changes may be made within the scope of the present invention. For example, in other embodiments of the invention it is envisaged that various of the features described in the illustrated embodiments may be combined or separated as is suitable. Furthermore, the number of primary spring components may differ from that described; for example, six or eight or other numbers of primary spring components may be utilised and in dependence thereon, the configuration of the first coupling mechanism and/or, where incorporated, the second coupling mechanism, may have a greater or fewer number of components accordingly.

The application of the torsional vibration damper system disclosed herein is not limited to use in a dual mass flywheel or to vehicles having a manual transmission. It is envisaged that the torsional vibration damper system disclosed herein may be used in other launch devices.

As used herein the term "pin" may refer, but not exclusively, to a typical cylindrical type pin, in addition the term "pin" may refer to pins having other shapes and structures including pins that are formed as part of on or within other components, for example, integral or formed parts of a first or second lever, primary mass, secondary mass, absorber mass or any other component of the torsional vibration damper system as appropriate.

The following numbered paragraphs contain statements of invention:

1 . A torsional vibration damper system comprising: a primary mass, a secondary mass, and a primary damper means, the primary mass and secondary mass being rotatably coupled to one another such that the primary mass and the secondary mass can rotate relative to one another, the primary damper means comprising a primary damper spring disposed between the primary mass and secondary mass for damping torsional vibrations and comprising a first coupling mechanism configured and arranged to adjust, in situ, a stiffness of the coupling between the primary mass and the secondary mass.

2. A torsional vibration damper system according to paragraph 1 , wherein said first coupling mechanism comprises:

(i) a first lever;

(ii) a first moveable fulcrum pin about which the first lever can pivot; and

(iii) a first actuation means for adjusting the position of the first moveable fulcrum pin relative to the first lever, wherein a first node of the first lever is pivotally mounted to the primary mass and wherein a second node of the first lever is coupled to said primary damper spring.

A torsional vibration damper system according to paragraph 2 wherein the first lever comprises a first elongate slot; wherein the secondary mass comprises a second elongate slot and wherein movement of the first moveable fulcrum pin is restricted by said first and second elongate slots, and wherein the first coupling mechanism further comprises a first bottom pin extending from the second node of the first lever by which the first lever is coupled to said primary damper spring.

A torsional vibration damper system according to paragraph 3 wherein the first actuation means causes the first moveable fulcrum pin to move toward the first or toward the second node of the first lever and in dependence upon a position of the first moveable fulcrum pin the ratio of the first lever is adjusted and in dependence upon said position of the first moveable fulcrum pin, the first lever increases the effective stiffness of the primary damper spring.

A torsional vibration damper system according to paragraph 4, wherein the first actuation means is either passively and/or actively operated.

A torsional vibration damper system according to paragraph 5, wherein the first actuation means comprises a driver and a phaser plate, the phaser plate comprising a third elongate slot and the driver being coupled to the phaser plate for controllably rotating the phaser plate for moving the first moveable fulcrum pin, which thereby adjusts the effective length of the lever which in turn affects the primary damper spring and effectively adjusts the stiffness of the coupling between the primary mass and the secondary mass.

A torsional vibration damper system according to paragraph 5, wherein the first fulcrum pin moves radially, wherein the primary and secondary masses rotate and wherein the driver is provided by any one or a combination of: a linear-to-rotary driver, a hydraulic mechanism, a cam mechanism, and an electric motor and the first actuation means is therefore actively operated.

A torsional vibration damper system according to paragraph 5, wherein the driver comprises a return spring, wherein one end of the return spring is coupled to the first moveable fulcrum pin and wherein the other end of the return spring is affixed to the phaser plate and the first actuation means is therefore passively operated.

9. A torsional vibration damper system according to paragraph 8 wherein the return spring is a non-linear spring and comprises at least one of: a variable rate axial spring component acting in a linear motion; a fixed rate axial spring component acting in a nonlinear motion; a variable rate torsional spring, acting in a linear motion and a fixed rate torsional spring, acting in a non-linear motion. 10. A torsional vibration damper system according to paragraph 7 wherein the driver comprises a return spring, wherein one end of the return spring is coupled to the second moveable fulcrum pin and wherein the other end of the return spring is affixed to the phaser plate and the first actuation means is therefore actively and passively operated. 1 1 . A torsional vibration damper system according to paragraph 1 wherein the torsional damper further comprises a secondary damper means for further reducing torsional vibrations, wherein the secondary damper means is actively or passively adjustable and is configured and arranged for further reducing torsional vibrations across a range of torsional vibration frequencies.

12. A torsional vibration damper system according to paragraph 3 wherein the torsional damper further comprises a secondary damper means for further reducing torsional vibrations, wherein the secondary damper means is actively or passively adjustable and is configured and arranged for further reducing torsional vibrations across a range of torsional vibration frequencies and wherein said secondary damper means comprises an absorber mass and a second coupling mechanism and wherein the absorber mass is provided as a single annular disc disposed about the primary and secondary masses.

13. A torsional vibration damper system according to paragraph 12 wherein said second coupling mechanism comprises:

(i) a second lever;

(ii) a second moveable fulcrum pin about which the second lever can pivot;

(iii) a secondary damper spring and

(iv) a second actuation means for adjusting the position of the second moveable fulcrum pin relative to the second lever,

wherein a first node of the second lever is pivotally mounted to the absorber mass and wherein a second node of the second lever is coupled to said secondary damper spring. A torsional vibration damper system according to paragraph 13 wherein the second lever comprises a fourth elongate slot; wherein the secondary mass comprises a fifth elongate slot and wherein movement of the second moveable fulcrum pin is restricted by said fourth and fifth elongate slots. A torsional vibration damper system according to paragraph 14 wherein said secondary damper spring comprises more than one spring component and wherein the second damper means further comprises a second bottom pin extending from the second node of the second lever, by which second bottom pin the second lever is coupled to a spring component of said secondary damper spring. A torsional vibration damper system according to paragraph 15, wherein the first bottom pin of the first damper means and the second bottom pin of the second damper means are offset from one another and the first bottom pin contacts a spring component of the primary damper spring and the second bottom pin contacts a spring component of the secondary damper spring. A torsional vibration damper system according to paragraph 16 wherein the second actuation means causes the second moveable fulcrum pin to move between the first and second nodes of the second lever and in dependence upon a position of the second moveable fulcrum pin the effective length of the second lever is adjusted and in dependence upon said position of the second moveable fulcrum pin a frequency of torsional vibration damped by movement of the absorber mass is adjusted. A torsional vibration damper system according to paragraph 17, wherein the second actuation means is either passively or actively operated. A torsional vibration damper system according to paragraph 18, wherein the second actuation means comprises a driver and a phaser plate, the phaser plate comprising a sixth elongate slot and the driver being coupled to the phaser plate for controllably rotating the phaser plate and for moving the second moveable fulcrum pin, which thereby adjusts the effective length of the second lever which in turn affects the frequency of torsional vibration damped by movement of the absorber mass and wherein the driver is provided by any one or a combination of: a linear-to-rotary driver, a hydraulic mechanism, a cam mechanism, and an electric motor and the second actuation means is therefore actively operated and/or wherein the driver comprises a return spring, wherein one end of the return spring is coupled to the second moveable fulcrum pin and wherein the other end of the return spring is affixed to the phaser plate and the second actuation means is therefore passively operated. 20. A torsional vibration damper system according to paragraph 19 wherein the first actuation means of the first coupling mechanism and the second actuation means of the second coupling mechanism are provided by a shared actuation means comprising a single phaser plate and a shared drive means. 21 . A torsional vibration damper system according to paragraph 20 wherein the primary damper spring comprises more than one spring component; wherein the secondary damper spring comprises more than one spring component; said spring components are circumferentially arranged and accommodated within an aperture within the secondary mass; and wherein the absorber mass is provided as an annular mass disposed circumferentially about the primary and secondary masses; and wherein the secondary mass comprises a number of elongate slots corresponding to the number of spring components of the primary and secondary springs.

22. A torsional vibration damper system according to paragraph 21 wherein the first coupling mechanism comprises more than one first lever, more than one first moveable fulcrum pin and more than one first bottom pin; and wherein the second coupling mechanism comprises more than one second lever, more than one second moveable fulcrum pin and more than one second bottom pin. 23. A torsional vibration damper system according to paragraph 1 wherein the torsional damper further comprises a secondary damper means for further reducing torsional vibrations, wherein the secondary damper means is actively or passively adjustable and is configured and arranged for further reducing torsional vibrations across a range of torsional vibration frequencies, wherein said secondary damper means comprises an absorber mass and a second coupling mechanism comprising:

(i) a second lever;

(ii) an extension portion;

(iii) a secondary damper spring;

(iv) a second moveable fulcrum pin about which the second lever can pivot; and (v) a second actuation means for adjusting the position of the second moveable fulcrum pin relative to the second lever, wherein a first node of the second lever is pivotally mounted to the absorber mass, wherein a second node of the second lever is coupled to said secondary damper spring, and wherein the extension portion of said second lever is affixed to the primary mass. 24. A torsional vibration damper system according to paragraph 23 wherein the second lever comprises a fourth elongate slot; wherein the secondary mass comprises a fifth elongate slot and wherein movement of the second moveable fulcrum pin is restricted by said fourth and fifth elongate slots and wherein the second damper means comprises a second bottom pin extending from the second lever, by which second bottom pin, the second lever is coupled to a spring component of said secondary damper spring.

25. A torsional vibration damper system according to paragraph 24 wherein the absorber mass is provided as a single annular disc disposed about the primary and secondary masses.

26. A dual mass flywheel incorporating a torsional vibration damper system according to paragraph 1 , wherein a primary flywheel is provided by said primary mass and a secondary flywheel is provided by said secondary mass. 27. A dual mass flywheel according to paragraph 26 for use in a motor vehicle.

28. A vehicle comprising the torsional vibration damper system according to paragraph 1 .

Claims

A torsional vibration damper system comprising: a primary mass, a secondary mass, and a primary damper means, the primary mass and secondary mass being rotatably coupled to one another such that the primary mass and secondary mass can rotate relative to one another, the primary damper means comprising a primary damper spring disposed between the primary mass and secondary mass for damping torsional vibrations and comprising a first coupling mechanism configured and arranged to adjust, in situ, a stiffness of the coupling between the primary mass and the secondary mass.

A torsional vibration damper system according to claim 1 wherein the primary damper spring comprises one or more primary damper compression spring components.

A torsional vibration damper system according to claim 1 or 2, wherein said first coupling mechanism comprises:

(i) a first lever;

(ii) a first moveable fulcrum pin about which the first lever can pivot; and

(iii) a first actuation means for adjusting the position of the first moveable fulcrum pin relative to the first lever,

A torsional vibration damper system according to claim 3, wherein a first node of the first lever is pivotally mounted to the primary mass and wherein a second node of the first lever is coupled to said primary damper spring.

A torsional vibration damper system according to claim 4 wherein the first lever comprises a first elongate slot; wherein the secondary mass comprises a second elongate slot and wherein movement of the first moveable fulcrum pin is restricted by said first and second elongate slots.

A torsional vibration damper system according to claim 3, 4 or 5 wherein the first coupling mechanism further comprises a first bottom pin, coupling the first lever to said primary damper spring.

7. A torsional vibration damper system according to claim 5 wherein the first coupling mechanism further comprises a first bottom pin extending from the second node of the first lever by which the first lever is coupled to said primary damper spring. 8. A torsional vibration damper system according to claim 7 wherein the first actuation means causes the first moveable fulcrum pin to move toward the first or toward the second node of the first lever and in dependence upon a position of the first moveable fulcrum pin the ratio of the first lever is adjusted and in dependence upon said position of the first moveable fulcrum pin, the first lever increases the effective stiffness of the primary damper spring.

9. A torsional vibration damper system according to claim 8, wherein the first actuation means is either passively and/or actively operated. 10. A torsional vibration damper system according to claim 9, wherein the first actuation means comprises a driver and a phaser plate, the phaser plate comprising a third elongate slot and the driver being coupled to the phaser plate for controllably rotating the phaser plate for moving the first moveable fulcrum pin, which thereby adjusts the effective length of the lever which in turn affects the primary damper spring and effectively adjusts the stiffness of the coupling between the primary mass and the secondary mass.

1 1 . A torsional vibration damper system according to claim 10 , wherein the first fulcrum pin moves radially, wherein the primary and secondary masses rotate and wherein the driver is provided by any one or a combination of: a linear-to-rotary driver, a hydraulic mechanism, a cam mechanism, and an electric motor and the first actuation means is therefore actively operated.

12. A torsional vibration damper system according to claim 10, wherein the driver comprises a return spring, wherein one end of the return spring is coupled to the first moveable fulcrum pin and wherein the other end of the return spring is affixed to the phaser plate and the first actuation means is therefore passively operated.

13. A torsional vibration damper system according to claim 12 wherein the return spring is a non-linear spring and comprises at least one of: a variable rate axial spring component acting in a linear motion; a fixed rate axial spring component acting in a non-linear motion; a variable rate torsional spring, acting in a linear motion and a fixed rate torsional spring, acting in a non-linear motion.

14. A torsional vibration damper system according to claim 10 the driver comprises a return spring, wherein one end of the return spring is coupled to the second moveable fulcrum pin and wherein the other end of the return spring is affixed to the phaser plate and the first actuation means is therefore actively and passively operated.

15. A torsional vibration damper system according to any preceding claim wherein the torsional damper further comprises a secondary damper means for further reducing torsional vibrations, wherein the secondary damper means is actively or passively adjustable and is configured and arranged for further reducing torsional vibrations across a range of torsional vibration frequencies.

A torsional vibration damper system according to claim 15 wherein said secondary damper means comprises an absorber mass and a second coupling mechanism.

A torsional vibration damper system according to claim 16, wherein the absorber mass is provided as a single annular disc disposed about the primary and secondary masses.

A torsional vibration damper system according to claim 17 wherein said second coupling mechanism comprises:

(i) a second lever;

(ii) a second moveable fulcrum pin about which the second lever can pivot;

(iii) a secondary damper spring and

19. A torsional vibration damper system according to claim 18, wherein the secondary damper spring comprises one or more secondary damper compression spring components. A torsional vibration damper system according to claim 19, wherein a first node of the second lever is pivotally mounted to the absorber mass and wherein a second node of the second lever is coupled to said secondary damper spring.

A torsional vibration damper system according to claim 20 wherein the second lever comprises a fourth elongate slot; wherein the secondary mass comprises a fifth elongate slot and wherein movement of the second moveable fulcrum pin is restricted by said fourth and fifth elongate slots. 22. A torsional vibration damper system according to claim 21 wherein the second coupling mechanism further comprises a second bottom pin extending from the second node of the second lever, by which second bottom pin the second lever is coupled to a spring component of said secondary damper spring. 23. A torsional vibration damper system according to claim 22 when dependent upon claim 7, wherein the first bottom pin of the first damper means and the second bottom pin of the second damper means are offset from one another and the first bottom pin contacts a spring component of the primary damper spring and the second bottom pin contacts a spring component of the secondary damper spring.

24. A torsional vibration damper system according to claim 23 wherein the second actuation means causes the second moveable fulcrum pin to move between the first and second nodes of the second lever and in dependence upon a position of the second moveable fulcrum pin the effective length of the second lever is adjusted and in dependence upon said position of the second moveable fulcrum pin, a frequency of torsional vibration damped by movement of the absorber mass is adjusted.

A torsional vibration damper system according to claim 24, wherein the second actuation means is either passively or actively operated.

A torsional vibration damper system according to claim 25, wherein the second actuation means comprises a driver and a phaser plate, the phaser plate comprising a sixth elongate slot and the driver being coupled to the phaser plate for controllably rotating the phaser plate and for moving the second moveable fulcrum pin, which thereby adjusts the effective length of the second lever which in turn affects the frequency of torsional vibration damped by movement of the absorber mass.

27. A torsional vibration damper system according to claim 26 wherein the driver is provided by any one or a combination of: a linear-to-rotary driver, a hydraulic mechanism, a cam mechanism, and an electric motor and the second actuation means is therefore actively operated.

28. A torsional vibration damper system according to claim 27, wherein the driver comprises a return spring, wherein one node of the return spring is coupled to the second moveable fulcrum pin and wherein the other node of the return spring is affixed to the phaser plate and the second actuation means is therefore passively operated.

29. A torsional vibration damper system according to claim 28 wherein the driver is provided by any one or a combination of: a linear-to-rotary driver, a hydraulic mechanism, a cam mechanism, and an electric motor and the driver comprises a return spring, wherein one end of the return spring is coupled to the second moveable fulcrum pin and wherein the other end of the return spring is affixed to the phaser plate and the second actuation means is therefore actively and passively operated.

30. A torsional vibration damper system according to any of claims to 26 to 29 wherein the first actuation means of the first coupling mechanism and the second actuation means of the second coupling mechanism are provided by a shared actuation means comprising a single phaser plate and a shared drive means.

31 . A torsional vibration damper system according to claim 30 wherein the primary damper spring comprises more than one spring component, the secondary damper spring comprises more than one spring component, said spring components are circumferentially arranged and are each accommodated within an aperture within the secondary mass; and wherein the absorber mass is provided as an annular mass disposed circumferentially about the primary and secondary masses; and wherein the secondary mass comprises a number of elongate slots corresponding to the number of spring components of the primary and secondary damper springs.

32. A torsional vibration damper system according to claim 31 wherein the first coupling mechanism comprises more than one first lever, more than one first moveable fulcrum pin and more than one first bottom pin; and wherein the second coupling mechanism comprises more than one second lever, more than one second moveable fulcrum pin and more than one second bottom pin.

33. A torsional vibration damper system according to claim 1 or 2 wherein the torsional damper further comprises a secondary damper means for further reducing torsional vibrations, wherein the secondary damper means is actively or passively adjustable and is configured and arranged for further reducing torsional vibrations across a range of torsional vibration frequencies, wherein said secondary damper means comprises an absorber mass and a second coupling mechanism comprising:

(i) a second lever;

(ii) a second moveable fulcrum pin about which the second lever can pivot;

(iii) a secondary damper spring; and

wherein a first node of the second lever is pivotally mounted to the absorber mass, wherein a second node of the second lever is coupled to said secondary damper spring, and wherein an extension portion of said second lever is affixed to the primary mass.

34. A torsional vibration damper system according to claim 32 wherein the second lever comprises a fourth elongate slot; wherein the secondary mass comprises a fifth elongate slot and wherein movement of the second moveable fulcrum pin is restricted by said fourth and fifth elongate slots.

35. A torsional vibration damper system according to claim 33 wherein the second damper means comprises a second bottom pin extending from the second lever, by which second bottom pin the second lever is coupled to a spring component of said secondary damper spring.

36. A torsional vibration damper system according to claim 32, 33 or 34 wherein the absorber mass is provided as a single annular disc disposed about the primary and secondary masses.

37. A dual mass flywheel incorporating a torsional vibration damper system according to any preceding claim, wherein a primary flywheel is provided by said primary mass and a secondary flywheel is provided by said secondary mass.

38. A dual mass flywheel according to claim 37 for use in a motor vehicle.

39. A vehicle comprising the torsional vibration damper system according to any preceding claim 1 to 36. A vehicle comprising the dual mass flywheel according to claim 37 or 38.

A torsional vibration damper system, dual mass flywheel, or vehicle substantially described herein with reference to and/or as illustrated by the accompanying Figures.