Rotary shafts – gudgeons – housings – and flexible couplings for ro – Torque transmitted via flexible element – Coil spring
Reexamination Certificate
2000-03-02
2002-03-19
Browne, Lynne H. (Department: 3629)
Rotary shafts, gudgeons, housings, and flexible couplings for ro
Torque transmitted via flexible element
Coil spring
C188S378000, C188S379000, C074S573110
Reexamination Certificate
active
06358153
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to a vibration damping device for a drive system of a motor vehicle having a base body arranged for rotating about an axis of rotation and a deflection mass arrangement arranged in the base body and having at least one deflection mass and a deflection path associated with the at least one deflection mass and along which the deflection mass is movable during rotation of the base body about the axis of rotation, the deflection path having a vertex area and deflection areas proceeding in opposite directions from the vertex area.
2. Description of the Related Art
A vibration damping device is disclosed in German reference DE 44 26 317 A1 having a plurality of deflection paths arranged in a base body and distributed about an axis of rotation of the base body. Deflection masses arranged in the base body are movable along these deflection paths which extend in the circumferential direction from vertex areas and curved toward the axis of rotation of the base body. During rotary operation of the base body, centrifugal forces arrange the deflection masses in respective vertex areas of the deflection paths, the vertex areas having the greatest radial distance from the axis of rotation. In the event of irregularities in the rotating speed, for example, as a result of rotational irregularities in an internal combustion engine drive, the deflection masses are deflected from their rest position in the vertex areas by these irregularities in rotational speed and move along their deflection paths in an oscillating manner. Higher harmonic orders of vibrational excitations in particular may be damped by so-called speed-adaptive dampers as described above. These dampers are adaptable to a specific vibration frequency to be damped through the selection of the radii of curvature of the curved paths and through the selection of the masses and dimensions of the respective deflection masses.
However, a problem with these prior art devices occurs when additional vibrational excitations occur, especially vibrational excitations of a different frequency or type. For example, when the above described vibration damper is used in a drivetrain in a motor vehicle between the crankshaft of an internal combustion engine and a transmission input shaft, an axial offset or axial inclination may be generated which forces the components of a clutch that are coupled together effect wobbling movements. Such wobbling movements also occur at certain frequencies and may impair the drive system.
SUMMARY OF THE INVENTION
It is the object of the present invention to further develop a vibration damping device that provides an improved damping function with respect to additional vibrational excitations.
The object is met according to a first embodiment of the present invention by a vibration damping device a motor vehicle drive system comprising a base body which is rotatable about an axis of rotation and deflection mass arrangement arranged in the base body and having at least one deflection mass and a deflection path associated with the at least one deflection mass and along which the deflection mass is movable during rotation of the base body about the axis of rotation. The deflection path has a vertex area and deflection areas proceeding in opposite directions from the vertex area.
The deflection areas proceed from the vertex area in substantially opposite axial directions. According to this embodiment, the deflection path extends substantially in the axial direction. The deflection area proceeding in the axial direction curves toward the axis of rotation of the base body. Therefore, the deflection mass moves substantially in a plane containing the axis of rotation. This movement of the deflection mass is substantially orthogonal to the movement direction of commonly known deflection masses and may be used to damp or eliminate wobbling excitations of the rotatable base body.
To further compensate for fluctuations in the rotational speed of the rotating system which are known per se and which originate, for example, from out-of-true running of an internal combustion engine, the deflection path associated with the at least one deflection mass has further deflection areas which proceed from the vertex area in substantially opposite circumferential directions.
In this embodiment, every deflection mass may accordingly move in an axial direction and in a circumferential direction, wherein an approach to or a distancing from the axis of rotation of the base body occurs in both the axial direction movements and the circumferential movements as a result of the curvature of the different paths. The deflection areas in the axial direction are connected with the additional deflection areas in the circumferential direction to form a deflection field for the associated deflection mass, wherein this deflection field faces the axis of rotation and is curved toward the axis of rotation. Accordingly, the at least one deflection body moves on a surface which is curved in three-dimensional space.
To arrange the movements such that they are as identical as possible in any direction, the at least one deflection mass forms a substantially spherical deflection body.
In a further embodiment of the present invention, the object of the invention is met by a vibration damping device for a motor vehicle drive system comprising a base body arranged for rotating about an axis of rotation and a deflection mass arrangement arranged in the base body having a plurality of deflection masses and a deflection path associated with every deflection mass and along which the deflection masses are movable during rotation of the base body about the axis of rotation.
This embodiment further comprises at least two deflection masses having a different mass and/or a different mass moment of inertia.
By providing different masses or mass moments of inertia in a plurality of deflection masses, each of these different deflection masses forms an oscillator with a different natural frequency. In this way, different excitations occurring in the rotating system at different frequencies may be simultaneously reduced.
This result may also be achieved by incorporating two differently configured deflection paths in addition to or instead of the two different masses or mass moments. The different paths may, for example, have a different curvature shape or have a different radial positioning with respect to the axis of rotation.
In an arrangement of this kind, the different deflection masses or deflection paths may be arranged so as to follow one another in the circumferential direction and/or arranged so as to follow one another in the axial direction depending on space considerations.
The above-stated object of adapting to very different frequency ratios is met according to another embodiment of the present invention in that at least one deflection path extends at least partly in a viscous damping medium. In addition, the natural frequency of the oscillator generated in this way may accordingly be influenced due to the fact that the deflection mass moving along the path must move in the medium and against increased resistance.
In this embodiment, a plurality of deflection paths may be arranged following one another in the circumferential direction. Each of the deflection paths defines a respective damping medium chamber and at least two of the damping medium chambers are connected with one another by a channel arrangement. In an arrangement of this type, the damping medium fluid may be displaced back and forth between the individual damping medium chambers. The back-and-forth displacement also has a determined natural frequency and therefore influences the oscillation behavior of the damper.
In this connection, the channel arrangement may open into the respective deflection paths defining the damping medium chamber.
Further, a channel arrangement may be arranged in the at least one deflection mass for the entrance of or passage of damping medium.
The viscous damping medium may comprise a damp
Carlson Cora
Peinemann Bernd
Weth Jürgen
Browne Lynne H.
Cohen, Pontani, Liberman & Pavane
Dunwoody Aaron M
Mannesmann Sachs AG
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