Robert Boschgmbh

Michael Goldbach

Reiner Knoell

Marco Knoell

Gottfried Hendrix

Thomas Gellner

An electromechanical linear actuator includes a threaded drive which has a threaded spindle and a threaded nut. The threaded spindle is coupled to a hollow shaft of an electric motor via a rotationally fixed connection. The threaded nut is fastened to a linearly movable extension tube. In a maximally retracted state of the extension tube, the threaded nut is retracted at least in portions, preferably completely, into the interior of the hollow shaft. During operation of the linear actuator, the threaded spindle rotates and is not moved linearly. The threaded nut does not rotate and is moved linearly.

Electromechanical linear actuator with hollow shaft motor

A linear actuator having a threaded drive including a nut connected to a cantilever tube and a leadscrew coupled to a motor, so that, by rotation of the leadscrew, the threaded nut and the cantilever tube are linearly movable, and, regardless of the position of the cantilever tube, one end the leadscrew projects into the cantilever tube and is connected to a piston which divides an internal space formed by the cantilever tube into a first region on the side of the piston opposite the threaded nut and a second region on the side of the piston facing the nut. The two regions are separated from one another in a fluidically sealed manner. A relief of the threaded drive is improved since the first region is connected to a pressure accumulator to generate a relief pressure in the first region using the first pressure source.

Linear actuator

A linear actuator has a screw drive having a threaded nut connected to an extension arm tube and a threaded spindle couplable to a motor. A first end of the spindle always projects into the tube and is connected to a piston which partitions an interior space formed by the tube into a first region on the side of the piston opposite to the nut and a second region on the side of the piston facing the nut. The regions are separated in a fluid-tight manner. The spindle is held in position since the nut comprises an annular piston that delimits an annular fluid space between a housing of the linear actuator and the tube in a fluid-tight manner, the hydraulically effective surface of which is the same size as that of the first region. The first region and the annular fluid space are fluidically connected by a switching valve.

An electromechanical linear actuator having a threaded drive, which comprises a threaded nut connected to a cantilever tube and a lead screw connected to a hollow shaft of an electric motor via a rotationally fixed connection in such a way that, by a rotation of the hollow shaft and the lead screw, the threaded nut and the cantilever tube are linearly movable. An axial design length of the electromechanical linear actuator in the maximally retracted state is minimized in that a holding brake for the lead screw and a first rotary bearing for bearing the lead screw on a housing of the linear actuator are arranged within the hollow shaft.

Electromechanical linear actuator

A servohydraulic drive includes a hydrostatic displacement machine, an electric machine that is mechanically speed-coupled with the displacement machine, a hydraulic cylinder that is fluidically connected to the displacement machine via first and second working lines, a hydraulic accumulator, and a supply unit. The displacement machine has a stroke that is adjustable via a hydraulic adjustment device. The cylinder is configured to be activated by reversal of the fluid flow through the displacement machine in opposite directions. The accumulator is preset to a low pressure and is fluidically connected via a valve assembly in each case to the lower pressure working line. The supply unit is configured to supply the adjustment device with pressurized fluid under the necessary pressure for the adjustment regardless of the present pressure in the working lines such that the displacement machine is configured for an active and load pressure-independent adjustment of its stroke volume.

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Lohr a. Main, Germany

Michael Goldbach