Rotary shafts – gudgeons – housings – and flexible couplings for ro – Torque transmitted via flexible element – Coil spring
Reexamination Certificate
1999-10-27
2002-05-28
Browne, Lynne H. (Department: 3629)
Rotary shafts, gudgeons, housings, and flexible couplings for ro
Torque transmitted via flexible element
Coil spring
C192S201000, C192S211000, C464S002000, C464S081000
Reexamination Certificate
active
06394908
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to torsional vibration dampers (hereinafter referred to as torsional vibration dampers of the kind specified) which comprise an input member for connection with a vehicle engine and an output member for connection with a vehicle transmission, the members being mounted for limited relative rotation about a common axis against a damping means to damp torsional vibrations in the engine/transmission.
Such torsional vibration dampers are often in the form of a twin mass flywheel in which the input and output members comprise input and output flywheel masses mounted for relative rotation via a support bearing acting between the masses.
Alternatively the input and output members can be of relatively small mass as shown, for example, in the Figures of the Applicant's earlier British patent application No. 98 03046.3.
BACKGROUND OF THE INVENTION
The damping means of such torsional vibration dampers can take a wide range of forms, for example, the damping means may comprise one or more of the following:
one or more circumferentially acting compression springs;
one or more circumferentially acting elastomeric compression blocks;
one or more friction devices;
one or more hydraulic damping devices, and
one or more bob-weights connecting linkages (which generate speed dependent damping) connected between the members.
Such torsional vibration dampers therefore tend to be relatively complex devices which consist of a relatively large number of individual parts and are therefore relatively expensive to manufacture.
There is also a requirement to provide an axially compact torsinal vibration damper.
SUMMARY OF THE INVENTION
It is an objective of the present invention to provide a torsional vibration damper of the kind specified with fewer individual parts which is therefore easier and cheaper to manufacture.
It is a further objective of the present invention to provide a torsional vibration damper of the kind specified which is of an axially compact design.
Thus according to one aspect of the present invention in a torsional vibration damper of the kind specified the damping means comprises one or more circumferentially acting compression springs, the or each spring acting between a first abutment formed as an integral part if the input member and a second abutment formed as an integral part of the output member.
Such a construction is particularly advantageous when the torsional vibration damper is a twin mass flywheel with the input mass formed as a single piece sheet metal pressing with integral first spring abutments and the output mass is a cast component with integrally cast second spring abutments.
The construction is also particularly compact in an axial sense which is an important feature of twin mass flywheels for use in congested engine compartments particularly when the engine is disposed transversely relative to the vehicle.
The torsional vibration damper may also include one or more elastomeric springs or blocks which are subjected to compression in end zones of the relative rotation of the input and output members.
In accordance with a further aspect of the present invention such elastomeric springs or blocks are mounted on one of the input or output members between first circumferentially facing abutments formed on or carried by said member and are acted upon by further circumferentially facing abutments formed on or carried by the other member. The elastomeric springs or blocks may also be located radially by a radially outer abutment formed on one of the input or output members. In a preferred and particularly convenient construction both the first circumferentially facing abutments and the radial abutment of each elastomeric spring or block are formed integrally on the input member which may conveniently be formed as a single piece pressing.
Each elastomeric spring or block may be supported by a sheet metal casing member which sits in a window in the input or output member which supports the block or spring.
In accordance with a further aspect of the present invention in a torsional vibration damper of the kind specified which includes circumferentially acting compression springs, the circumferentially acting compression springs are each supported at a radially inner location by a support member (typically of general channel configuration) to avoid fouling adjacent elastomeric springs or blocks which are located radially inwardly of the compression springs. The spring support members deflect the compression springs from their natural straight configuration to an accurate form which bridges the elastomeric springs or blocks.
In a particularly convenient arrangement, in a vibration damper employing bob-weight connecting linkages, the compression spring support member may rest at one end on the radially outer abutment associated with each elastomeric springs or block and may be also fastened at the other end to a pivot pin of an adjacent associated bob-weight connecting linkages.
In accordance with a further aspect of the present invention a torsional vibration damper of the type specified may also be provided with a friction damping device whose frictional damping effect varies with the amount of relative rotation of the input and output members of the damper.
For example, such a rotation dependent damping device may comprise a friction member which is carried by the input or output member and biased into contact with a surface on the other of the input or output members to provide frictional damping. The surface against which the friction member is biased may be in the form of a cam surface orientated with respect to the axis of relative rotation of the input and output members so that the contact pressure of the friction member on the surface increases with relative rotation between the input and output members. The friction member may be arranged to contact the surface only in the last end portion of the relative rotation. In a particularly convenient arrangement the member which is biased into contact with the surface may also act as a stop which co-operates with abutments on the other of the input or output members to limit the relative rotation between the input and output members.
In accordance with a still further aspect of the present invention, in a torsional vibration damper which includes bob-weight connecting linkages, the bob-weights may each be pivotally mounted on one of the input and output members by a cantilevered pivot pin. Each bob-weight may be free to move axially to a limited extent on its cantilevered pin.
The use of cantilevered pivot pins further reduces the axial dimensions of the torsional vibration damper.
Each linkage may be completed by a single flexible link pivoted at one end on the associated bob-weight and at its other end on the other of the input or output members. The single flexible link may conveniently be located on the input member side of the bob-weight.
In a further construction the cantilevered pivot pins and the main support bearing which supports the input and output members for relative rotation are both retained in position by a common retaining member.
The bob-weight may be mounted on the cantilevered pin via a bearing bush which is a press fit in the bob-weight. Similarly the flexible link may be pivoted to the bob-weight via a second bush which is a press fit in the bob-weight and a rivet which carries its own collar and which extends through the second bush.
The flexible link may be pivoted on the other of the input or output members via a stud or other fixing on which the link is sandwiched between a flange formed on a sleeve surrounding the stud or other fixing and a washer.
In accordance with a still further aspect of the present invention a twin mass flywheel of the kind specified includes a friction damping device whose friction damping effect varies with the speed of rotation of the flywheel.
The damping effect may be arranged to decrease (or increase) with the speed of rotation depending on the operating characteristics required from the flywheel. For example, the fr
Lambert Adam Johnson
Young Alastair John
Automotive Products, PLC
Browne Lynne H.
Dunwoody Aaron
Milliken Paul E
Weber Ray L
LandOfFree
Torsional vibration dampers does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Torsional vibration dampers, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Torsional vibration dampers will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2912788