Rotary shafts – gudgeons – housings – and flexible couplings for ro – Torque transmitted via flexible element – Coil spring
Reexamination Certificate
2000-02-14
2001-10-23
Browne, Lynne H. (Department: 3629)
Rotary shafts, gudgeons, housings, and flexible couplings for ro
Torque transmitted via flexible element
Coil spring
C464S068800, C192S213200
Reexamination Certificate
active
06306043
ABSTRACT:
The present invention relates to a torsion damper for a double flywheel for a motor vehicle.
More precisely, it relates to a circumferentially acting torsion damper for a double flywheel for a motor vehicle, which is adapted to be disposed kinematically between the primary and secondary flywheels of the double flywheel, being of the kind comprising a first element adapted to be coupled to the primary flywheel, which is itself arranged to be coupled to the crankshaft of the engine of the vehicle, a second element adapted to be connected to the secondary flywheel, which is adapted to receive a clutch mechanism, the said damper including resilient means associated with friction means; as is known, such an arrangement gives excellent absorption of torsional oscillations generated by the engine, especially in slow running, resulting in a substantial reduction in noise, especially in the gearbox.
In this configuration, the torsion damper is of course one that operates with a high displacement; generally for this purpose, the resilient means are long helical springs, most commonly pre-curved, which are fitted in an annular channel formed mainly in the primary flywheel; having regard to the substantial length of the springs, the said annular channel is frequently at least partially filled with grease, and it is usual to place, between the outer periphery of the springs and the interior of the annular channel, a component for protection against wear; as is known, such an arrangement, of the same kind as that described for example in the document FR-A-2 601 104, is cumbersome.
It has previously been proposed to have, in a torsion damper, a group of springs disposed circumferentially so as to work in series through interposed phasing rings: this arrangement is described for example in the document U.S. Pat. No. 4,484,898; but here again, the arrangement is complicated, with the primary and secondary elements of the damper, and more particularly the second element, being provided with blinker-shaped supplementary members for locating the springs, in particular against the centrifugal force to which they are subjected, and despite the fact that the springs are of short length since, in the damper described in that document, there are three groups of three springs working in series.
The object of the present invention is to overcome these drawbacks.
Thus, according to the invention, a double flywheel for a motor vehicle, arranged to be disposed kinematically between the primary and secondary flywheels of the double flywheel, the first flywheel being adapted to be connected to the crankshaft of the engine of the vehicle and the secondary flywheel being adapted to receive a clutch mechanism, of the kind comprising a first element adapted to be connected to one of the said flywheels and a second element adapted to be connected to the other one of the said flywheels, the said damper including resilient means associated with friction means, the said resilient means consisting of at least one first group of springs working in series through interposed first phasing rings, is characterised by the fact that the said resilient means include a second group of springs working in series through interposed second phasing rings, the said first groups and second groups of springs working in series through an interposed phasing assembly.
Advantageously, each set consisting of the set of first groups and the set of second groups of springs is disposed on a pitch circle, and the two pitch circles are of different diameters. Preferably, the two pitch circles are in a common transverse plane at right angles to the axis of the damper, with one pitch circle surrounding the other. Preferably, the first element surrounds the second element. Thus, it is possible to obtain high angular displacements between the primary and secondary flywheels with a damper which is smaller in the axial sense and is of simple form.
Advantageously, the first element and the second element lie in the said transverse plane.
Preferably, the first element consists of a flat annular ring referred to as a first ring, having holes for fastening it to one of the flywheels, and radial lugs referred to as first lugs and having engagement surfaces and locating surfaces for the springs.
Advantageously, the second element consists of a flat annular ring referred to as a second ring, having holes for fastening it to the other one of the flywheels, and radial lugs, referred to as second lugs, having engagement surfaces and locating surfaces for the springs.
In another version, the first element is in the form of a hollow cover plate having an outer peripheral flange and a base portion which are joined together by a cylindrical skirt portion, the base portion having a central aperture and the flange being formed with holes for fastening it to one of the flywheels, with radial lugs referred to as first lugs, including engagement surfaces for the springs, projecting from the base portion and extending transversely in a plane which is offset axially inwards with respect to the plane of the base portion; preferably, the second element is in the form of a hollow cover plate having an external peripheral flange and a base portion which are joined together by a cylindrical skirt portion, the base portion having a central aperture and being formed with holes for fastening it to the other one of the flywheels, with radial lugs, referred to as second lugs and including engagement surfaces for the springs, being obtained by reforming the flange so that they lie transversely in a plane which is offset axially inwards with respect to the plane of the remainder of the flange.
Preferably, the phasing rings are frusto-conical in form and formed with oblique lugs having engagement surfaces and locating surfaces for the springs in the group of springs with which they are associated, the said oblique lugs intersecting the pitch circle of the said group of springs, the phasing rings being generally in a transverse plane spaced away from the transverse plane of symmetry of the damper. Thus, symmetrical transmission of the forces is obtained.
In an advantageous arrangement, the phasing assembly is an annular ring of generally X-shaped cross section defining wheel felloes, which include a first window for the first group of springs, together with a second window for the second group of springs.
Preferably, the inner peripheral portion and the outer peripheral portion of the said felloes are frusto-conical and are adapted to constitute means for centering and for rotational guiding of the phasing rings.
In another advantageous arrangement, the phasing assembly consists, inexpensively, of two identical members which are assembled back-to-back, each of the members being an annular ring of generally V-shaped cross section, the axis of which is parallel to the axis of the damper.
Preferably, the radial rings of the first element have a thickness smaller than that of the annular body of the said element and are connected to the inner periphery of the latter, which is frusto-conical with a cone angle corresponding to that of the first phasing rings.
Advantageously, the radial lugs of the second element have a thickness which is smaller than that of the annular body of the said element and are connected to the outer periphery of the latter, which is frusto-conical, with a cone angle corresponding to that of the second phasing rings.
In a further version, the phasing rings are generally flat and are provided with radial lugs which extend inwardly and include engagement surfaces and locating surfaces for the springs of the group of springs with which they are associated, the said lugs lying, by virtue of press-formed projecting elements, in a transverse plane which is offset axially with respect to the transverse plane in which the major part of the rings lies.
Preferably, the phasing assembly is a flat disc with a central aperture and includes a first window for the first group of springs, together with a slot, bounding the central aperture, for the first group of springs.
Advanta
Annic Pascal
Cho Hyoun Nam
Browne Lynne H.
Liniak Berenato Longacre & White
Thompson Kenn
Valeo
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