Machine element or mechanism – Gearing – Teeth
Reexamination Certificate
1999-04-12
2001-01-09
Fenstermacher, David (Department: 3682)
Machine element or mechanism
Gearing
Teeth
C074S089100, C074S424830
Reexamination Certificate
active
06170351
ABSTRACT:
FIELD OF THE INVENTION
The invention concerns a device for converting a rotary motion into an axial motion, which device has a threaded spindle, a nut concentrically surrounding the threaded spindle with a clearance and a plurality of axially parallel rollers guided in a cage and arranged in the clearance, said rollers have a circumferential profile by which they mesh with the external thread of the threaded spindle and with the corresponding internal thread of the nut, each of said rollers is axially displaceable within the cage by the dimension of the thread pitch during a rotation of the nut relative to the threaded spindle, while at the end of such a rotation, each roller is re-displaceable within an axial groove of the nut into the starting position by a cam arranged in the vicinity of each end face of the cage.
BACKGROUND OF THE INVENTION
Such roller screw drives for converting a rotational motion into a translational motion are used mainly in cases in which, for operational reasons, no high precision of pitch and position is required but rather, an economic solution with a high degree of efficiency and good bearing capacity. Such a roller screw drive is known from DE-OS 21 50 739. This drive comprises a solid nut body and two likewise solid annular cam members which mesh by regions having annular cam surfaces with annular end recesses of a cage for the rollers. The manufacturing of this device is highly complicated so that the resulting construction is very expensive.
SUMMARY OF THE INVENTION
The object of the invention is to create a roller screw drive which has a simpler structure and is more economic to manufacture.
The invention achieves this object by the fact that the nut is a thin-walled sheet metal sleeve made by non-chipping shaping which is pressed into a bore of the housing which receives the device. This permits a considerable reduction of material so that the device also has a lesser weight. Due to being pressed in, the thin-walled sheet metal sleeve receives its precision of shape and dimension.
The sheet metal sleeve can be drawn from a circular blank. During the drawing process, the axial groove for the return displacement of the rollers can be formed at the same time. The internal thread of the sheet metal sleeve can be made by roller-burnishing.
It is, however, also possible to make the sheet metal sleeve by bending out of a sheet metal strip on which an internal thread has previously been made by rolling, and then welding the thus formed sleeve along the abutting edges. One of the cams for the return displacement of the rollers can be formed on a flange of the sheet metal sleeve and a further cam for the return displacement of the rollers can be configured on a disc inserted into and fixed in the sheet metal sleeve. A disc profiled by non-chipping shaping is suitable for this purpose. By bending over an adjacent rim of the sheet metal sleeve, the disc can be axially fixed in the sheet metal sleeve. It is also possible to fix the disc axially in the sheet metal sleeve by swaging the material of the disc and/or the material of the sleeve.
The thread of the spindle and the groove profile of the rollers can also be made by roller-burnishing.
By the pressing-in of the device into the bore of the housing, the required radial clearance and pre-tension of the roller screw drive is obtained. If necessary, a selective matching of rollers and spindles can be carried out.
REFERENCES:
patent: 3884090 (1975-05-01), Dock
patent: 4993849 (1991-02-01), Radinger et al.
patent: 5370012 (1994-12-01), Stanley
patent: 5836208 (1998-11-01), Dietrich et al.
patent: 6026696 (2000-02-01), Hehl
patent: 410542 (1966-10-01), None
patent: 665459 (1988-05-01), None
patent: 2150739 (1972-04-01), None
patent: 4131486 (1993-03-01), None
patent: 0603067 (1994-06-01), None
Bierman, Muserlian and Lucas
Fenstermacher David
Ina Walzlager Schaeffler OHG
LandOfFree
Device for converting a rotational movement into an axial... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device for converting a rotational movement into an axial..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device for converting a rotational movement into an axial... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2445134