Rotary shafts – gudgeons – housings – and flexible couplings for ro – Torque transmitted via flexible element – Element is leaf spring
Reexamination Certificate
1999-05-07
2001-05-29
Browne, Lynne H. (Department: 3629)
Rotary shafts, gudgeons, housings, and flexible couplings for ro
Torque transmitted via flexible element
Element is leaf spring
C464S101000, C188S290000, C192S208000
Reexamination Certificate
active
06238294
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a torsional vibration damper or a torsionally elastic coupling, comprising an inner portion and an outer portion and radial leaf spring assemblies between inner portion and outer portion, where the leaf spring assemblies each include two leaf springs, and at the one end are clamped between adapters and are fixed at the outer portion, and at the other end engage in axial grooves of the inner portion.
DESCRIPTION OF THE PRIOR ART
In these dampers or couplings the leaf spring assemblies are used for torque transmission and due to their spring-elastic properties at the same time allow to influence the occurring torsional vibrations. The spring assemblies are firmly clamped into the outer portion, but to compensate occurring relative movements between inner portion and outer portion, their inner ends engage only loosely into the axial grooves of the inner portion, where in this case the introduction of force is effected via the groove flanks and the abutting spring ends. In the case of torsional vibrations there are relative movements both between the groove flanks and the abutting spring ends and between the individual leaf springs of the spring assemblies, where the leaf springs of a spring assembly, which are directly abutting against each other, are subjected to an alternating bending load due to the torsional vibrations, which impairs the load-bearing capacity of the springs and their service life and in the areas of contact leads to considerable wear phenomena. To improve these friction and wear conditions between the leaf springs, it has also been proposed already to separate the individual leaf springs from each other by means insertion plates made of bronze or a similar sliding material, which insertion plates substantially extend over the entire length of a leaf spring and lead to a certain improvement of the friction and wear behavior, but cannot reduce the alternating load of the leaf springs and can hardly contribute to a prolongation of the service life and an increased utilization of the spring.
It is therefore the object underlying the invention to create a torsional vibration damper or a torsionally elastic coupling as described above, which with simple means provides for an increase in the degree of spring utilization while at the same time reducing the frictional forces and the risk of wear.
SUMMARY OF THE INVENTION
This object is solved by the invention in that the two leaf springs of the leaf spring assemblies protrude radially inwards from the clamping area up to the ends engaging in the axial grooves by maintaining a mutual free clearance of movement. Due to the free clearance of movement between the individual leaf springs, always only the one leaf spring abutting against the groove flanks is subjected to a bending load in the case of a relative rotation between inner portion and outer portion, whereas the other leaf spring is lifted off the groove flank and remains free from load. Depending on the respective direction of vibration, torsional vibrations accordingly cause a bending of the one spring and then a bending of the other spring, so that the individual leaf springs are always only subjected to an increasing bending load, but never to an alternating bending load. Since in addition the two inwardly protruding leaf springs remain without mutual contact, no frictional forces occur between the same, and also the wear phenomena are restricted to the area where the spring ends engage in the axial grooves. Since there is no alternating bending load of the leaf springs, the springs themselves can be utilized more effectively and provide for taking up or transmitting larger forces, and thus lead to a comparatively smaller design.
To ensure the free clearance of movement between the leaf springs, the leaf springs can have a correspondingly wedge-shaped tapered cross-section along their length starting from the clamping area, but the two leaf springs of the leaf spring assemblies can also be separated from each other by insertion plates merely extending over the clamping area. These insertion plates then serve as spacers between the leaf springs and allow to adapt the size of the mutual spring distance to different conditions.
When between the adapters and the leaf springs of the leaf spring assemblies there are furthermore inserted insertion plates extending merely over the clamping area, these insertion plates can influence the respective distance between the leaf springs and the adapters mostly protruding up to shortly before the surface area of the inner portion so as to form throttle gaps, and even with a continuous radial extension of the adjacent side faces of adapters and leaf springs can ensure the required clearance between adapters and leaf springs.
REFERENCES:
patent: 1652520 (1927-12-01), Eaton
patent: 3534839 (1970-10-01), Campbell et al.
patent: 3996767 (1976-12-01), Geislinger
patent: 4104891 (1978-08-01), Geislinger
patent: 4307585 (1981-12-01), Chivari
patent: 5364308 (1994-11-01), Vollet
patent: 332668 (1976-10-01), None
patent: 3033302 (1988-12-01), None
patent: 2250569 (1994-08-01), None
Browne Lynne H.
Collard & Roe P.C.
Dunwoody Aaron
Ellergon Antriebstechnik GmbH
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