Rotary shafts – gudgeons – housings – and flexible couplings for ro – Torque transmitted via flexible element – Coil spring
Reexamination Certificate
1999-01-06
2001-05-08
Oberleitner, Robert J. (Department: 3613)
Rotary shafts, gudgeons, housings, and flexible couplings for ro
Torque transmitted via flexible element
Coil spring
C464S064100, C464S068800, C192S10700R
Reexamination Certificate
active
06227976
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention concerns a torsional vibration damper with at least one tangential spring on a disk, and more particularly concerns such devices wherein the spring is mounted in a window or recess open on the radially outward side, and wherein the device is provided with a guide member which extends internally within the spring to limit or prevent excessive bending in the radial direction when the spring is subjected to high centrifugal force.
Conventional torsional vibration dampers usually have several tangential springs at regular intervals that are held in windows of the primary part. These windows have radial sides between which the spring is clamped, and they have tangential sides of which the radially outmost side prevents the spring from bulging too much at high speeds. The spring is tightly held in the window so that it is kept from bending undesirably or slipping out from its mount even when centrifugal force is high.
The invention is based on the problem of developing the generic torsional vibration damper so that the spring is held in a different manner. This problem is solved in that the torsional vibration damper has a guide which extends far enough into the spring to prevent the spring from bending in a radial direction.
The guide according to the invention allows the spring to be located on the perimeter of a primary part or a secondary part of a torsional vibration damper to increase the torque that acts on the spring. The window does not have to be limited to the outside in a radial direction. With the spring mounted according to the invention, the radially interior parts of the spring press on the inside of the guide at high speeds to prevent excess radial bulging of the spring.
The advantage is that either the torsional vibration damper can have a smaller diameter, or its capability is increased by a spring with the same dimensions that may be positioned farther out radially.
It is particularly advantageous when the disk is a part of the secondary part. When the springs are on the secondary part, the spring guide according to the invention is particularly useful since, for design reasons, a window limit lying radially to the outside is not necessary. The spring can be affixed in a U-shaped recess to the disk of the secondary part, and the outside of the spring extends up to the radially outermost area of the disk.
In order to attach the guide to two opposing points on the disk, it is suggested that the guide extend across the entire length of the spring. Contact surfaces on the faces of the spring are suitable to hold the spring in a set position and allow several springs to be arranged coaxially.
The guide can be easily affixed by giving it an interlocking fit with the disk. However, depending on the use, it can be affixed by welding or plastic deformation such as upsetting. It is particularly advantageous when the guide can be clipped to the disk. It is suggested that the guide or a part of the guide be deformable. When the guide is deformable, it is easier to insert the disk and allows a snap-in fit.
Since the guide is to resist radially-acting centrifugal force resulting from its own mass and the mass of the spring, it is particularly advantageous when the guide can be deformed perpendicular to the plane of the disk during installation. Such a selective deformability makes it easier to install the guide, and the strength of the guide is not impaired by radially-acting force.
In one preferred exemplary embodiment, the guide has recesses in a projection that moves in a plane of the disk on opposing faces to interact with the disk. The guide can be made of a homogenous material, and different thicknesses of the parts of the guides can make it selectively deformable.
A preferred material for the guide is plastic since it allows economic manufacture and different elasticity and strengths.
Although the guide has been described as being deformable, especially to produce a snap-in fit, it is also possible to make the disk out of plastic or at least make it flexible so that a snap-in fit can be attained by deforming the disk.
SUMMARY OF THE INVENTION
The invention is an improved torsional vibration damper device comprising a disk member in which are tangentially mounted at least one and preferably plural helical springs. The springs are mounted in generally U-shaped recesses or windows having opposing sides to retain ends of the spring. The windows or recesses are open to the radially outward side, such that no limiting wall or cap is necessary for retention of the spring in the recess. Excessive bending of the spring during exposure to high centrifuigal forces is prevented or limited by providing a guide member which extends from each opposing face into the interior of the spring. The interior surface of the guide abuts the spring to prevent excessive radial bending. The guide preferably extends completely through the entire length of the spring between the opposing sides, and may have a concave interior surface. The guide may be formed of a deformable material, such as metal or plastic, such that a pressure or snap fit may be achieved between the guide and the opposing sides of the spring recess, which preferably has recesses of various configuration to receive the ends of the guide.
REFERENCES:
patent: 1258639 (1918-03-01), Eaton
patent: 1284268 (1918-11-01), Eaton
patent: 2321941 (1943-06-01), Rose
patent: 2342989 (1944-02-01), Ware
patent: 2674863 (1954-04-01), Thelander
patent: 2984091 (1961-05-01), Ludwig
patent: 4518071 (1985-05-01), Nozawa
patent: 5657845 (1997-08-01), Szadkowski et al.
Heidingsfeld Dietmar
Rohs Ulrich
Kramer Devon
Oberleitner Robert J.
Saitta Thomas C.
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