Zf Friedrichshafen Ag

Florian Weinl

Thomas Schwegler

Dirk Leutheuser

Maik Wiesner

Julia Klein

Armin Gierling

Matthias List

Tobias Miller

Michael Pantke

Armin Haugg

Ulrich Schmidt

Michael Linder

Michael Jud

Sven Jabs

Arthur Strehlau

Andreas Bisping

Christoph Stritt

Sebastian Deeg

In a device for locking a piston rod of a piston of an actuator, an armature rod of an electromagnet is axially movable counter to a preloading spring and includes two actuating contours. Latching mechanisms are operable to mechanically fix the piston. An axial distance between base points of the actuating contours is such that the piston is mechanically fixable by only one of the latching mechanisms in each case. Interlocking elements of both latching mechanisms are accommodated in an axially fixed manner in a sleeve, are radially displaceable, and are selectively engageable with the piston.

Device for locking a piston rod of a piston of an actuator which is pressurizable in order to disengage a parking lock and is spring-loaded in order to engage the parking lock

A device () for actuating a parking lock device () of an automatic transmission includes a piston () guided in a cylinder () and hydraulically displaceable counter to a spring force of an actuation spring (). The piston () is form-lockingly fixable in a first position and in a second position by radially displaceable blocking elements () of a blocking device (). The blocking elements () are radially displaceable by an actuation element (). The radial displacement path of the blocking elements () and an operating condition of the actuation element () corresponding thereto in the first position of the piston () deviate from the radial displacement path of the blocking elements () and the operating condition of the actuation element () corresponding thereto in the second position of the piston ().

Device for actuating a parking lock means of an automatic transmission and method for operating such a device

A parking lock includes a locking pawl () and an interlocking element () arranged on a connecting bar () to a selector lever (). The end of the connecting bar () facing away from the interlocking element () is articulatedly connected to the selector lever (). A hydraulically actuatable actuator () includes two pistons () provided for disengaging the parking lock. During normal operation, a detent device (), which is actuatable by an electromagnet (), locks the first piston () in a piston position corresponding to an engaged condition (P_ein) or a disengaged condition (P_aus). Without requiring activating the electromagnet () to release the detent device (), the parking lock, during normal operation, is manually disengagable with an emergency disengagement device () acting upon the second piston () and is manually engagable with an emergency engagement device () acting upon the detent device ().

Parking lock for an automatic transmission in a motor vehicle

A device for locking a piston rod of a piston includes a latching mechanism actuatable by an actuating element. The actuating element is fixedly arranged on an armature rod of an electromagnet, is clamped between two preloading springs, and includes two actuating contours. Components of the device are configured with respect to geometry and with respect to forces acting upon each of the components such that a permanent magnet holds the armature rod in a first position in the non-energized condition of an electromagnet and in the engaged condition of the parking lock and such that the electromagnet holds the armature rod in a second position in the energized condition and in the disengaged condition of the parking lock. The parking lock is disengageable in the pressurized condition of the piston and in the energized condition of the electromagnet, and the parking lock is engageable in the non-pressurized condition of the piston and in the non-energized condition of the electromagnet.

A device for locking a piston rod of a piston of an actuator is provided. An electrically actuatable electromagnet includes an armature rod, which is axially movable counter to a first preloading spring and on which two actuating elements are axially displaceably mounted between two stops of the armature rod. A second preloading spring is axially mounted between the two actuating elements. The actuating elements each include actuating contours, which are associated with latching mechanisms, via which the piston is mechanically fixable in a disengaged condition and in a engaged condition of the parking lock.

A parking lock for a transmission of a motor vehicle having an interlocking element of a connecting rod that is biased against a parking lock disengagement direction to bring and keep a ratchet tooth of a locking pawl in engagement with a tooth space of a parking interlock gear during an engagement of the parking lock. The connecting rod is provided a spring force acting in a parking lock engagement direction from an inserting spring and a compressive force acting in the parking lock disengagement direction from a hydraulically actuatable actuator having first piston pressurizable to disengage the parking lock. A detent device actuatable by an electromagnet mechanically fixes the first piston in either a latched or unlatched piston position associated with an engaged or disengaged position of the parking lock, respectively. A system determines a current engagement position of the detent device by assessing an inductance at the electromagnet.

Parking interlock in a vehicular transmission

A plurality of inductive loads () are connectable in parallel with one another between first and second terminals (), to which a controllable voltage () is applied. A method () for operating the loads () includes the steps of detecting () the connection of a previously non-energized load () between the terminals (); setting () the voltage () to a predetermined first value (), and, after the lapse of a predetermined time interval (), adjusting the voltage () to a predetermined second value (), with the second value () being lower than the first value ().

Inductive load control

A method of assessing a pulse-width-modulated signal in which the pulse-width-modulated signal to be assessed is applied to a first input of a microcontroller and a signal, that depends on the pulse-width-modulated signal being assessed, is applied to a second input of the microcontroller for assessment. The pulse-width-modulated signal being assessed is applied to a voltage divider to produce the signal that depends on the same. For the pulse-width-modulated signal to be assessed and for the signal that depends on the same, in each case, the microcontroller determines a time interval between signal edges of the respective signal, and the signal is assessed on the basis of a difference between the time interval between the signal edges in the pulse-width-modulated signal to be assessed and the time interval between the signal edges in the signal that depends on the same.

Method and circuit for assessing pulse-width-modulated signals

A method of activating an electromagnetic actuator having at least one coil and a movable armature. The method includes the step in which the electromagnetic actuator is demagnetized by passing a sequence of electric current pulses with a current flow direction which alternates from one current pulse to the next and with a current size which decreases from one current pulse to the next, through the at least one coil, in order to reduce or eliminate any residual magnetic flux density in the electromagnetic actuator. The method also includes a step in which a position of the movable armature is determined, after the demagnetization step, by passing a measurement current pulse through the at least one coil.

Method and drive apparatus for driving an electromagnetic actuator

An electromagnetic control device has a coil with a central axis and an interior space, and a control element that moves along the axis and is arranged at least partially within an interior space of the coil. The control element comprises an armature that axially moves to a desired position when the coil is energized. The coil is divided into at least two separate portions that are arranged axially behind one another and connected electrically in series with one another. An electric central tap is provided, between two adjacent coil portions, by which a sensor current, provided for determining an axial position of the armature, can be fed into a subset of the coil portions. When the armature is in a defined axial position, an axial end face of the armature is located within an axial area determined by an axial separation zone provided between two adjacent coil portions.

Growing community of inventors

Bodolz, Germany

Florian Weinl