Rotary shafts – gudgeons – housings – and flexible couplings for ro – Torque transmitted via flexible element – Coil spring
Reexamination Certificate
1999-06-25
2001-10-09
Browne, Lynne H. (Department: 3629)
Rotary shafts, gudgeons, housings, and flexible couplings for ro
Torque transmitted via flexible element
Coil spring
C192S213120
Reexamination Certificate
active
06299540
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a torsional vibration damping device for use in the drive train of a motor vehicle having at least two rotationally connected coaxial cover plates which rotate about an axis of rotation within a certain angular range relative to a coaxial part located between the cover plates.
2. Description of the Related Art
Torsional vibration dampers are required to damp the rotational vibrations fundamentally occurring in internal combustion engines. These rotational vibration generate droning noises in the vehicle body and also generate noises in the downstream gearbox and differential of the vehicle. The elastic forces typically used to accept the rotational vibration and deliver a torque which is as even as possible must, on the one hand, be sufficiently small for effective damping and, on the other hand, must accept high accelerations or forces. A large rotational deflection and therefore a large angle of twist between the two relatively rotatable parts are therefore desirable in the torsional vibration damping device.
Prior art torsional vibration damping devices are known, for example, from German Patent Application P 39 22 730.8. This reference discloses a clutch disk with a torsional vibration damping device having a hub disk arranged between two cover plates which are rotationally fastened together and held apart at a fixed distance by flat distance pieces. The cover plates can be rotated relative to the hub disk about the axis of rotation within limits which are determined by the circumferential size of apertures in the hub disk for the passage of the distance pieces. The radial distance of the distance piece from the axis of rotation is substantially determined by strength considerations and is balanced against weight and space requirements of the cover plates and hub disk. On the one hand, arranging the distance pieces at a distance from the axis of rotation which is as large as possible is desirable in order to keep the forces on the connections to the cover plates as small as possible. On the other hand, an increase in the radial size of the cover plates is not desirable with respect to weight and space requirement of the clutch disk.
When a minimum material thickness for the joint region of the distance pieces in the cover plates is taken into account, it follows that—in the current prior art—the apertures extending in the peripheral direction must be located outside the circumferential region of the spring elements. That is, the maximum twist angle of torsional vibration damping devices of the prior art is limited to the angular range between two spring elements.
SUMMARY OF THE INVENTION
The object of the invention is, therefore, to provide a torsional vibration damping device which can execute a clearly larger rotational angle with the same strength and the same dimensions as the prior art devices.
A further object of the invention is to ensure substantially higher strength with the usual small rotational angles of conventional torsional vibration damping devices.
To achieve this object, the present invention comprises a distance piece for connecting the two cover plates having joint regions of the distance piece where the distance piece is connected to the cover plates and a connecting region of the distance piece between the joint regions which connects the two cover plates. The radial distance between the connection region of the distance piece and the axis of rotation differs from the radial distance between the joint region of the distance piece and the axis of rotation. This permits the connecting region of the distance elements to be accommodated, in a space-saving manner, radially outside the spring element region. In consequence, the maximum angle of twist is not limited to the angular range between two spring elements and can be clearly increased without impairing the strength of the torsional vibration damping device. Similarly, it is also possible to substantially increase the strength of a torsional vibration damping device if larger angles of twist are sacrificed.
The internally located part such, for example, as a hub disk arranged between the cover plates may be substantially circular and the distance pieces connecting the cover plates may be arranged such that the distance pieces extend radially outside the internally located part.
In a further embodiment, at least one aperture extends circumferentially over the periphery of the internally located part. The distance pieces are arranged such that they pass through the apertures. In this way, the internally located part can be made stronger in critical regions.
In addition, the aperture should be arranged radially outside the region of the spring elements in order to increase the angle of twist and, therefore, to circumferentially extend the aperture into the circumferential region of the spring elements.
The aperture may, for example, comprise an opening or cut-out of the internally located part, such as a slot extending in the circumferential direction or an elongated hole extending in the circumferential direction.
In another embodiment, this aperture is provided at an external periphery of the internally located part, where it can be produced particularly rapidly and at low cost.
In addition to maintaining the distance between the cover plates, the distance pieces may also be used to rotationally fix the cover plates to one another if the joint regions of the distance pieces are inserted into fitting openings in the cover plates.
Plug-in connections may be provided by means of which one or a plurality of distance pieces are connected to one or both of the cover plates. If the axial fastening of the cover elements is effected by another component, it is not necessary for the distance pieces to also axially fasten the cover plates and the plug-in connection may be used without further processing for the finally assembled torsional vibration damping device. The axial fastening may, for example, take place by a suitably designed frictional device. The fastening of a cover plate may, of course, also take place by a positive or form-fitting connection.
If the joint regions of the distance pieces are caulked into openings in the cover plates, a fastening device which prevents the cover plates from falling apart axially at the outside may be omitted.
In addition, it is advantageously possible to employ an embodiment such that at least one distance piece is configured in such a way that it interacts with a stop element of the internally located part. In this way, a stop device to protect from excessive twist is incorporated in the existing devices.
As an example, the connecting region of a distance piece may interact with the stop element of the internally located part.
In another embodiment, the stop element consists simply of a circumferential end surface of the aperture, by which means a suitable stop element can be applied to the internally located part without an additional operational step.
The position of the distance pieces relative to the spring element windows and the axis of rotation can, advantageously, be unambiguously determined by the shape of the joint region.
A further embodiment is then to design the joint region of a distance piece provided as part of the stop appliance so that the joint region is not rotationally symmetrical about an axis parallel to the rotational axis of the clutch disk. This prevents the distance piece from twisting when subjected to torque.
In yet another embodiment, the distance pieces are U-shaped such that the joint region and connecting region are radially separated from one another. The distance pieces consist of only one workpiece in this embodiment and are therefore assembled in a stronger and cheaper manner.
In an advantageous embodiment, distance pieces can be used which have at least two different cross-sections.
In addition, the central region of such a U-shaped distance piece should point substantially outward in the installed condition. By this means, a large radial distan
Binda Greg
Browne Lynne H.
Cohen & Pontani, Lieberman & Pavane
Mannesmann Sachs AG
LandOfFree
Torsional vibration damping device in the drive train of a... 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 damping device in the drive train of a..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Torsional vibration damping device in the drive train of a... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2568240