Machine element or mechanism – Elements – Flywheel – motion smoothing-type
Reexamination Certificate
1997-09-11
2001-04-03
Bucci, David A. (Department: 3682)
Machine element or mechanism
Elements
Flywheel, motion smoothing-type
C192S089250, C192S210100
Reexamination Certificate
active
06209419
ABSTRACT:
The present invention relates to a friction damping device which controls the relative rotation between first and second flywheel masses of a twin mass flywheel as used in a motor vehicle transmission assembly.
Typically such a motor vehicle transmission assembly has an engine for driving one flywheel mass, and a gear box which is driven by the other flywheel mass. The two flywheel masses can rotate relative to each other to a limited extent and have drive torque means acting between them which progressively resist relative rotation of the flywheel masses as the torque increases (i.e. at low torque levels the flywheel masses do not rotate significantly relative to each other but at higher torque levels, at the same engine speed, the flywheel masses rotate a greater amount relative to each other). Such drive torque means can be springs (well known in the art) or bob weights as shown, for example, in the Applicant's prior patent application GB91 02029.1. Damping devices are also provided which damp out fluctuations in relative rotation between the flywheel masses.
In some such vehicle transmission assemblies when the engine is idling, i.e. in the idle range, irregular low level torque fluctuations from the engine can be transmitted to the gear box and cause problems such as gear idle chatter. To cure such problems the damping device must produce a relatively low level of damping in the idle range.
When the engine produces a relatively higher mean level of torque and a gear has been selected and the vehicle is being driven by the engine (i.e. the vehicle is in the drive range and the relative rotation of the flywheel masses is in the drive direction) the flywheel masses can approach the limit of their relative rotation. Because the engine produces uneven torque output which fluctuates alternately above and below the mean level, these fluctuations can cause the flywheel masses to rattle against the stops which limit their relative rotation. To cure this problem the damping device needs to produce a relatively higher level of damping in the drive range. Since it is possible for the inertia of the vehicle to drive the engine i.e. the engine can be in the over-run range and the relative rotation of the flywheel masses is in the opposite over-run direction, the damping device needs to operate in both directions of relative rotation. Traditionally such damping devices are friction type devices.
It is an object of the present invention to provide an improved form of friction damping device for a twin mass flywheel.
It is a further object of the present invention to provide a friction damping device to control the relative rotation between the flywheel masses near a limit of relative rotation of the flywheel masses.
Thus in accordance with the present invention there is provided a twin mass flywheel having friction damping device capable of generating friction torque for controlling the relative rotation of a first and a second flywheel mass of the twin mass flywheel, the friction damping device comprising a first and a second friction member rotationally connected with an associated one of the flywheel masses, a third friction member sandwiched between the first and second friction members and which is rotationally connected with the other flywheel mass, and actuating means operative to axially displace the first and second friction members, relative to each other to modify the friction generated by the device upon rotation of the third friction member relative to the first or second friction members the second friction member having at least one first axially oriented portion operatively connected with the first friction member, each first axially orientated portion being in the form of a pronged fork with circumferentially outer surfaces of the prongs acting as a common drive formation for connecting the first and second friction members with said one flywheel mass by engaging torque transmitting abutments on side one flywheel mass with formations on the first friction member engaging between the prongs of the second friction member.
Also in accordance with the present invention there is provided a twin mass flywheel having a friction damping device for controlling the relative rotation of a first and a second flywheel mass of the twin mass flywheel, the friction damaging device comprising a substantially U-shaped clip with a base portion and two arm portions fixed rotationally fast with one flywheel mass, and a flange fixed rotationally fast with the other flywheel mass, the flange contacting and generating a frictional force with the arms of the U-shaped clip after a predetermined amount of relative rotation of the flywheel masses.
Also in accordance with the present invention there is provided a twin mass flywheel having a friction damping device for controlling the relative rotation of a first and a second flywheel mass of a twin mass flywheel, the friction damping device comprising a first friction component which rotates with the first flywheel mass and a second friction component which rotates with the second flywheel mass, the first and second friction components being biased into engagement to generate a friction damping force by a belleville spring and having co-operating surface formations arranged such that during relative rotation of the flywheel masses the belleville spring is compressed, a first surface of the belleville spring contacting a surface of a first adjacent component at an outer contact radius and a second surface of the belleville spring contacting a surface of a second adjacent component at an inner contact radius, at least one of the contacting surfaces being curved so that the ratio of the outer contact radius to the inner contact radius changes as the belleville spring is compressed.
Also in accordance with the present invention there is provided a twin mass flywheel having a friction damping device for controlling the relative rotation of a first and a second flywheel mass of the twin mass flywheel, the friction damping device comprising a first friction component which rotates with the first flywheel mass and a second friction component which rotates with the second flywheel mass, the first and second friction components being biased into engagement to generate a friction damping force by a belleville spring and having co-operating surface formations arranged such that during relative rotation of the flywheel masses the belleville spring is compressed, a first surface of the belleville spring contacting an associated surface of a first adjacent component at an outer contact radius and a second surface of the belleville spring contacting an associated surface of a second adjacent component at an inner contact radius, at least one of the contacting surfaces being provided with protrusions which are brought into contact with an associated other of the contacting surfaces during compression of the belleville spring such that the ration of the outer contact radius to the inner contact radius undergoes a step change after a predetermined amount of relative rotation of the two flywheel masses.
Also in accordance with the present invention there is provided a twin mass flywheel having a friction damping device for controlling the relative rotation of a first and a second flywheel mass of the twin mass flywheel, the friction damping device comprising a first friction component which rotates with the first flywheel mass and a second friction component which rotates with the second flywheel mass, the first and second friction components being biased into engagement to generate a friction damping force by a belleville spring and having co-operating surface formations arranged such that during relative rotation of the flywheel masses the belleville spring is compressed, a first surface of the belleville spring contacting a surface of a first adjacent component at an outer contact radius and a second surface of the belleville spring contacting a surface of a second adjacent component at an inner contact radius, the surface of the second adjacent component at t
Curtis Anthony John
Murphy Robert John
Automotive Products plc
Bucci David A.
Germain Lee A
Kim Chong H.
Milliken Paul E
LandOfFree
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