Machine element or mechanism – Elements – Flywheel – motion smoothing-type
Reexamination Certificate
1998-12-22
2001-09-11
Bucci, David A. (Department: 3682)
Machine element or mechanism
Elements
Flywheel, motion smoothing-type
C192S205000, C192S212000
Reexamination Certificate
active
06286390
ABSTRACT:
CROSS-REFERENCES TO RELATED APPLICATIONS
This application claims the priorities of German Patent Applications, Serial Nos. 197 57 556.0, filed Dec. 23, 1997, 197 57 562.5, filed Dec. 23, 1997, and 198 08 561.3 filed Feb. 28, 1998, the subject matters of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
The invention relates in general to a torsional vibration damper, and in particular to a torsional vibration damper, especially for couplings, and of a type including a primary structural unit and a secondary structural unit which are rotatable relative to one another and linked to each other by a spring arrangement incorporating at least one thrust piston, wherein at least the secondary structural unit interacts with the thrust piston of the spring arrangement via a contact surface with a radially directed surface component.
Such a torsional vibration damper is known, for example, from German Pat. No. 195 44 832 A1. This conventional torsional vibration damper includes a driving disk which partially overlaps a driven disk, and is formed on the inside of the overlapping part with radial pockets spaced about the periphery, with thrust pistons being situated inside the pockets and kept apart by at least one compression spring. The outer surface area of the driven disk has a polygonal cross section, and is in contact with the thrust piston. Thus, the outer surface area serves as a contact surface via which the driving disk so interacts with the spring arrangement comprised of the thrust piston and compression springs that the compression springs are compressed when the driving disk and driven disk are turned.
This torsional vibration damper is used in particular for couplings, with the driven disk being directly or indirectly connected with one of the friction surfaces.
SUMMARY OF THE INVENTION
It is thus an object of the present invention to provide an improved torsion vibration damper which has a structurally simple heat insulation.
This object, and others which will become apparent hereinafter, are attained in accordance with the present invention by providing a torsional vibration damper with primary and secondary structural units which are rotatable relative to one another and connected together by a spring arrangement which includes at least one thrust piston, wherein at least the secondary structural unit interacts with the thrust piston of the spring arrangement via a contact surface with a radially directed surface component, with the contact surface being formed on a separate third structural unit situated between the secondary structural unit and the spring arrangement.
Through the material transition from the secondary structural unit and separate third structural unit, which in and of itself already has an insulating effect, a heat insulation can be achieved in a structurally simple manner between the secondary structural unit and the spring arrangement, in particular the thrust pistons and the springs situated between the thrust pistons. This is particularly advantageous when the secondary structural unit is connected with a friction surface of a clutch, or exhibits such a friction surface.
In particular, the arrangement makes it possible to also use thrust pistons made of suitable material, such as plastics, whereby these materials are suitably selected to accomplish the task of achieving a wedging action and friction effect, without having to withstand excessive thermal loads.
The heat insulation can be further improved by only partially contacting the separate third structural unit with the secondary structural unit. In this way, the heat-transmitting overall surface between the third structural unit and the secondary structural unit is reduced, thereby increasing the thermal resistance between these two structural units. In order to comply with existing demands in conjunction with heat insulation and the stability of this arrangement, the separate third structural unit can be in partial contact with the secondary structural unit in an axial direction, i.e. parallel to the axis of rotation of the torsional vibration damper and/or in a peripheral direction.
In accordance to the present invention, the arrangement comprised of separate third structural unit and secondary structural unit can be configured in a structurally simple and yet stable manner, when the third structural unit includes at least one plate-shaped element which rests on a corresponding support surface of the secondary structural unit.
By configuring the separate third structural unit as a contact ring, the stability of the separate structural unit, and hence the stability of the entire arrangement can be further enhanced. In this context, it is also advantageous to provide the secondary structural unit with a support surface that radially supports the separate third structural unit, in particular if the third structural unit is of ring-shaped configuration. In this way, forces can be transmitted in a radial direction between the spring arrangement and the secondary structural unit, so as to avoid unnecessarily high axial forces for the torsional vibration damper according to the invention.
Suitably, the support surface of the secondary structural unit is smaller in an axial direction than the contact ring, so as to realize a partial contact in an axial direction between the separate structural unit and the secondary structural unit in a structurally simple manner. The secondary structural unit may also have projections which are spaced about the circumference for support of the contact ring, thereby establishing a partial contact between the secondary structural unit and the separate third structural unit in circumferential direction. Evidently, the aforementioned configurations may also be advantageously used in combination. In the event, the separate third structural unit is only placed on the secondary structural unit, the thermal resistance between the secondary structural unit and the separate third structural unit is maintained at a high level. It is also possible to only spotwise connect the separate structural unit with the secondary structural unit, so that the two structural units are in intimate contact at only these points. An intimate contact and hence good heat transfer between these two structural units, may be omitted if the separate structural unit and the secondary structural unit are so formed as to be positively joined together in circumferential direction.
It will be understood by persons skilled in the art that additional structural measures, such as recesses in the separate third structural unit, may be used to further increase the thermal resistance of the separate structural unit or between the secondary structural unit and the separate structural unit.
In order to ensure a sufficient stability of the separate structural unit even if the separate structural unit is only partially supported by the secondary structural unit, the separate structural unit may be made of metal, in particular of a less heat-conductive metal, such as special steel.
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patent: 5355747 (1994-10-01), Kajitani et al.
patent: 5551928 (1996-09-01), Sudau
patent: 5562542 (1996-10-01), Rohrle
patent: 5624317 (1997-04-01), Schierling et al.
patent: 5771755 (1998-06-01), Duclos et al.
patent: 5779550 (1998-07-01), Annic et al.
patent: 5916025 (1999-06-01), Fenioux et al.
patent: 41 18 686 (1992-12-01), None
patent: 195 44 832 (1997-06-01), None
Heidingsfeld Dietmar
Rohs Hans
Rohs Ulrich
Bucci David A.
Feiereisen Henry M.
Kim Chong H.
Rohs-Voigt Patentverwertungs-gesellschaft mbH
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