Patent Application
20060214453
The invention relates to an adjusting device for adjusting two parts relative to one another, having a fixed, sleeve-like housing and an adjusting component which is arranged in the housing and is led with its one end region out of a front-end opening of the sleeve-like housing, having a rotary drive, by means of which the adjusting component can be adjusted axially relative to the sleeve-like housing by means of an epicyclic mechanism.
Known as an adjusting component in such an adjusting device is a rotationally locked drive spindle which is displacable by a planetary roller mechanism relative to a hollow shaft provided with thread turns on its inside, the hollow shaft serving as rotor of an electric motor.
It is a disadvantage in this case that, for a large adjusting length, the hollow shaft and thus a rotatably driven component must also have a large overall length.
The object of the invention is therefore to provide an adjusting device of the type mentioned at the beginning which, in a simple construction, requires a small construction space and permits a manual adjustment of the parts to be adjusted relative to one another.
This object is achieved according to the invention in that the epicyclic mechanism is a recirculating ball mechanism, and the sleeve-like housing is arranged in a rotationally locked manner and is provided with a thread-turn-like groove on its cylindrical inner wall, and in that the rotary drive is arranged on the likewise rotationally locked adjusting component, this rotary drive having a drive shaft coaxial to the sleeve-like housing and having a thread-turn-like groove, the housing and the drive shaft being coupled to one another by balls arranged in the thread-turn-like grooves.
A further solution consists in the fact that the epicyclic mechanism is a planetary roller mechanism, and the sleeve-like housing is arranged in a rotationally locked manner and is provided with a thread on its cylindrical inner wall, and in that the rotary drive is arranged on the likewise rotationally locked adjusting component, this rotary drive having a drive shaft which is coaxial to the sleeve-like housing and by means of which one or more planetary rollers can be driven in a rotatable manner about the longitudinal axis of the sleeve-like housing or spindles parallel thereto, on which planetary rollers having grooves corresponding to the profile of the thread are in each case mounted in a freely rotatable manner, these planetary rollers engaging by means of their grooves in the thread of the sleeve-like housing.
Since the rotationally movable components move axially with the adjusting component, they may have a small overall length.
The recirculating ball mechanism and the planetary roller mechanism permit a high ratio of force transmission relative to the construction space, the linear movement being effected with a high reduction ratio. The reduction ratio is so high that an additional mechanism stage can usually be dispensed with.
Since, in the case of the planetary roller mechanism, the planetary rollers roll in the thread, there are only slight friction losses, so that the energy applied can serve for the adjusting largely free of losses. The rotary drive can therefore be designed to be relatively small and thus save construction space.
The result of the low friction losses is that the planetary roller mechanism is also not self-locking and thus easy manual adjustability of the parts adjustable relative to one another is also provided for.
The planetary rollers contribute substantially to rigidity of the adjusting device.
It is possible for a roller cage to be capable of being driven in a rotatable manner about the longitudinal axis by the coaxial drive shaft, this roller cage having the plurality of spindles which are parallel to the longitudinal axis of the sleeve-like housing and on which the planetary rollers having grooves corresponding to the profile of the thread are in each case mounted in a freely rotatable manner.
For more uniform force transmission, the spindles are preferably arranged in a uniformly distributed manner on a circle.
If the adjusting component is an adjusting tube, in the tube interior of which the rotary drive is arranged, the maximum adjusting stroke corresponds approximately to the overall length of the adjusting device in the retracted state.
To protect against the ingress of contaminants, the adjusting tube may be closed at its end projecting from the sleeve-like housing, the adjusting tube preferably also being led out of the sleeve-like housing in a sealed-off manner.
The rotary drive may be an electric motor, in particular a direct-current motor.
In order to also be able to transmit higher adjusting forces without any problems, the roller cage may be supported axially on the adjusting tube via an axial bearing, in particular an axial rolling bearing.
The roller cage may have a cage plate which is arranged on the drive shaft in a rotationally fixed manner and to which the axially extending spindles are fastened with their one end region.
For high stability of the roller cage, those ends of the spindles which are opposite the cage plate may be fastened to a second cage plate.
If the interior space of the sleeve-like housing is filled with a gas under prepressure, an extension movement of the adjusting tube can be effected either only by the gas pressure or by the gas pressure assisted by the rotary drive.
The extension movement of the adjusting component can also be assisted by a compression spring acting upon the adjusting component in the extension direction.
Use of nitrogen as pressurized gas additionally protects the housing and the components arranged in the adjusting tube against corrosion.
To convert the rotary movement of the drive shaft from a high speed to a high torque, the roller cage can be driven in a rotatable manner by the rotary drive via a mechanism stage.
A compact type of construction is achieved by an electronic driver for driving the rotary drive being arranged in the adjusting tube.
Furthermore, a temperature sensor for detecting the temperature in the adjusting device may be arranged in the adjusting tube, the output signal of which temperature sensor can be fed to the electronic driver.
To detect the adjusting speed and the adjusting travel, a speed sensor for detecting the revolutions of the drive shaft or of the roller cage may be arranged in particular in the adjusting tube.
In this case, the speed sensor used is preferably a Hall sensor.
Monitoring of the current for the rotary drive together with the speed information from the rotary sensor also enables obstructions to be detected in a sensitive manner.
The electronic driver can distinguish an open position from an obstruction by means of the detected stroke.
For fastening to the parts to be adjusted and if need be for the anti-rotation locking of sleeve-like housing and adjusting component, connection pieces for fastening to the parts to be adjusted relative to one another may be arranged on that end of the sleeve-like housing which is remote from the adjusting component and/or on that end of the adjusting component which is remote from the sleeve-like housing.
As preferred use, the adjusting component is arranged on a tailgate at a distance from a pivot axis of the tailgate, and the sleeve-like housing is arranged on a fixed body component of a motor vehicle.
An exemplary embodiment of the invention is shown in the drawing and is described in more detail below. The single FIGURE of the drawing shows an adjusting device in cross section.
The adjusting device shown has a sleeve-like housing 1 which is closed at its one end and is provided with a thread 2 on its cylindrical inner wall.
At its closed end, the housing 1 has a connection piece 3, with which it is pivotably fastened in a rotationally locked manner about its longitudinal axis 4 to a fixed component, such as, for example, the body of a vehicle.
Arranged on the housing 1 is an adjusting tube 5, which is led with its one closed end region out of the open end of the housing 1 in such a way as to be sealed off by an annular seal 6 and, via a further connection piece 11, is pivotably fastened in a rotationally locked manner about its longitudinal axis 4 to a movable component, such as, for example, a tailgate pivotably linked to the body of a vehicle.
The adjusting tube 5 is arranged in the housing 1 in such a way as to be movable in the direction of the longitudinal axis 4. Arranged in the adjusting tube 5 is a direct-current motor 7, the motor coils of which, as stator 8, are firmly arranged on the inner wall of the adjusting tube 5 and enclose a rotor 9 rotatably mounted coaxially to the longitudinal axis 4 and provided with permanent magnets.
At its end facing the connection piece 11, the rotor shaft 10 of the rotor 9 is rotatably mounted in the adjusting tube 5 via radial rolling bearings 12.
That end of the rotor shaft 10 which faces the connection piece 3 forms a drive shaft 13 for a roller cage 14 of a planetary roller mechanism 15.
The roller cage 14 consists of a first cage plate 16 firmly arranged on the drive shaft 13 and of a second cage plate 17 likewise firmly arranged at a distance therefrom on the drive shaft 13, these cage plates 16, 17 being connected to one another via spindles 18 which are arranged in a uniformly distributed manner on a circle coaxial to the longitudinal axis 4 and are parallel to the longitudinal axis 4.
In this case, the first cage plate is axially supported on the adjusting tube 5 via an axial bearing 19.
Planetary rollers 20 having grooves 21 at their cylindrical lateral surface which correspond to the profile of the thread are in each case mounted in a freely rotatable manner on the spindles 18, and these planetary rollers 20 engage in the thread 2 with their grooves 21 corresponding to the profile of the thread.
Arranged on the support 22 in the adjusting tube 5 is an electronic driver 23, from which a power-supply and control line 24 leads outwards. The direct-current motor 7 for the rotary drive of the planetary roller mechanism 15 can be driven by the electronic driver 23, which may also have a temperature sensor.
Also arranged on the adjusting tube 5 is a Hall sensor 25, by means of which the rotary movement of the drive shaft 13 can be detected and a corresponding signal can be supplied to the electronic driver 23.
The interior space of housing 1 and adjusting tube 5 is filled with nitrogen gas under prepressure.
To extend the adjusting tube 5, nitrogen gas is admitted to it in a piston-like manner and it is moved out of the housing 1. In the process, the rotor 9 and the planetary rollers 20 run along freely without substantial resistance.
To retract the adjusting tube 5, the drive shaft 13 and thus also the roller cage 14 are rotatably driven by the direct-current motor 7. As a result, the planetary rollers 20 roll with their external tooth system 21 in the thread 2 and move the adjusting tube 5 into the housing 1.
List of Designations
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2004 054 037.3 | Nov 2004 | DE | national |
