Zf Friedrichshafen Ag

Other

Christian Popp

Klaus Steinhauser

Thilo Schmidt

Georg Gierer

Peter Schiele

Bernd Allgaier

Hansj&ouml;rg Rosi

Friedrich Tenbrock

Jorg Arnold

Valentine Herbeth

Markus Herrmann

Christian Schwemer

Heinrich Zeller

Gerald Klein

Hansjorg Rosi

Peter Ziemer

Josef Haupt

Gabor Diosi

Armin Gierling

Anton Fritzer

Christoph Margraf

Alexander Haberstock

Jörg Arnold

Reinhard Vollmar

Armin Haugg

Rainer Grundler

Tobias Rolser

Christoph Braun

Sven Diebold

Stefan Meschenmoser

Ruben Cüppers

Manfred Scholz

Joerg Arnold

A device for operating a parking lock () of a transmission () includes an engagement spring () for engaging the parking lock (), a hydraulic actuator () for disengaging the parking lock (), an electrohydraulic control unit () for hydraulically actuating the actuator (), and an electronic control unit () for electrically actuating the actuator () and the electrohydraulic control unit (). The actuator () includes a hydraulic piston () operatively connected to the parking lock (), is actuatable by system pressure (P_sys) of the electrohydraulic control unit () via a pressure line () upon disengagement of the parking lock (), and is mechanically interlockable by an interlocking device (). A choke unit () includes an orifice () and a non-return valve () and is installed in the pressure line () downstream from the hydraulic piston ().

Device for operating a parking lock of a motor vehicle transmission

A hydraulic system for a transmission of a motor vehicle, the system having first and second pumps for conveying hydraulic fluid into primary and/or system-pressure circuits so that an intended pressure prevails in the circuits. The system further including liquid retention means preventing a flow of hydraulic fluid conveyed by the second pump from being conducted through the first pump when the first pump is not conveying and the second pump is conveying, and preventing a flow of hydraulic fluid conveyed by the first pump from being conducted through the second pump when the second pump is not conveying and the first pump is conveying. The system additionally including a sailing-mode lubricating valve for controlling, by an open-loop system, a flow rate of hydraulic fluid conveyed by the second pump into the primary and/or secondary system-pressure circuits such that the intended pressure is set in the system-pressure circuits.

Hydraulic system for a transmission of a motor vehicle

A device for actuating a locking mechanism, in particular for actuating a parking lock of a vehicle having an automatic transmission. The device comprises a piston which axially moves, a retaining device which is self-activating when the piston is in an axial position in which the locking mechanism is open to hold the piston in the axial position in which the locking mechanism is open, and an actuating device for actuating a release element, which deactivates the retaining device. To hold the piston in an axial position in which the locking mechanism is closed, the retaining device is self-activating, and can be deactivated to enable the piston to move, starting from the axial position in which the locking mechanism is closed, to the axial position in which the locking mechanism is open.

Device for actuating a locking mechanism

A mechanism for actuating a transmission having shifting elements. A self-holding valve device is movable into a first position, by a pilot pressure, against a force directed to a second position and held by a pressure holding signal in the first position. Transmission of a pressure signal, to a switching valve, is blocked by the self-holding valve device in the first position but, in the second position, is applied to the switching valve. When the driver sets the switching valve to a first shift position, the pressure signal can be applied to valve devices of at least two of the shifting elements that produce an actuating pressure and, in a second shift position of the switching valve, the onward transmission of the pressure signal, to the valve devices of the shifting elements that produce an actuating pressure, is blocked in the area of the switching valve.

Device for operating a transmission apparatus having a plurality of electrohydraulically actuated friction-fit and form-fit shift elements

A device for determining an operating state of a bi-directionally actuated hydraulic adjusting device of a transmission shifting element, which pressurizes active surfaces of a piston. The piston is biased to opposite end positions depending on which of a first active surface or a second active surface is pressurized with high pressure. The areas of the adjusting device, which can be pressurized with the pressure at the active surfaces of the piston, are connected with one another in positions of the piston element, between the end positions, via a throttle device. One of each area can be coupled for adjustment of the piston with the high-pressure area, and the other area with the low pressure area. An additional throttle device is provided upstream of the low pressure area and a pressure measuring device is provided upstream of the additional throttle device.

Device for determining an operating state of at least one bidirectionally actuable hydraulic adjusting device of a shifting element of a transmission device

A hydraulic transmission unit comprises at least one pressure regulation valve () and a pilot control valve () which is connected to the pressure regulation valve () by a pilot control line (). A pre-filling valve () sets a pre-filling pressure (p) to avoid draining of a clutch () and the lines () connected to the clutch () in an operating condition in which the clutch () is not actuated. To avoid draining when the clutch when in the operating condition, the pilot control line () is also connected to at least one line () which is pressurized with a second pre-filling pressure (p).

Hydraulic transmission control

A method of operating a vehicle drive-train with an engine and a transmission during a gearshift in which an interlocking shift element is disengaged and a frictional shift element is engaged. Upon a shift command, the shifting time and a transmission input speed are monitored. If the input speed deviates from a synchronous speed equivalent to the gear ratio being disengaged, recognizing disengagement of the interlocking shifting element. If an engaged operating condition of the interlocking shifting element to be disengaged is detected, after the lapse of a time interval beginning with the shift command, a current drive torque of the drive machine is brought by motor actuation to a level that corresponds to a difference between the current transmission input torque and a torque that can be transmitted by the frictional shifting element to be engaged, operating with slip, plus a torque offset value.

Method for operating a vehicle drive train

A method of operating a transmission of a vehicle drive train with at least one drive machine. The transmission is formed with at least one interlocking shift element and a plurality of frictional shift elements in order to obtain various gear ratios. During an engaging process of the interlocking shift element, starting from a disengaged operating condition, in which halves of the interlocking shift element are out of engagement, to an engaged operating condition, in which the shift element halves are interlocked in a rotationally fixed manner, when interlock between the shift element halves is obstructed, a rotational speed difference is produced at least temporarily between the shift element halves, at which the interlock in the area of the interlocking shift element can be engaged. To produce the speed difference between the shift element halves, the transmission capacity of at least one frictional shift element is increased.

Method for the operation of a transmission device of a vehicle drive train

A method is described for the operation of a transmission device () with a plurality of frictional shift elements (A, D, E, F) and at least one interlocking shift element (B, C) for obtaining various gear ratios. When a command is received for a gearshift during which the interlocking shift element (C) has to be changed from an open to a closed operating condition, the interlocking shift element (C) is at least approximately synchronized by increasing the transmission capacity of at least one frictional shift element (A) which does not have to be engaged in the force flow either to obtain the gear ratio that is to be disengaged or to obtain the gear ratio that is to be engaged.

Method for the operation of a transmission device

An automatic vehicle transmission comprises a first oil supply unit () with at least one mechanically driven first pump () and a second oil supply unit () with at least one electrically driven second pump (), and a valve device () and a clutch system (). The second oil supply unit () supplies the clutch system (), during a first operating condition, and the first oil supply unit () supplies the clutch system (), during a second operating condition.

Hydraulic system of a gear box

A method for operating a multi-step automatic transmission arranged in a drive train of a vehicle with a combustion engine. When downshifting from the third gear ratio to a second gear ratio, higher inertia must be shifted than when shifting from the third gear ratio to the first gear ratio. Upon a demand for a coasting downshift from the third gear ratio to the second gear ratio or to the first gear ratio with no performance demand on the combustion engine, the coasting downshift to the second gear ratio is not executed and the first gear ratio is engaged when the requirements for downshifting to the first gear ratio are met.

Method for operating a multi-step automatic transmission

A transmission oil pump for an automatic transmission of a motor vehicle. The speed of the oil pump can be shifted by a transmission (), that is arranged between the drive motor of the motor vehicle and the transmission oil pump, to a fast-running mode or a slow-running mode so that the oil pump can be operated at two different speed levels.

Oil pump for an automatic transmission and control method thereto

A method for operating a vehicle drivetrain () having a drive motor (), a transmission () and a drive output (). When a gear ratio change is called for in the transmission (), between an actually engaged gear and a target gear, one of a frictional or an interlock-type shift element is engaged in a flow of force in the vehicle drivetrain () and the other of an interlock-type or a frictional shift element is disengaged from the flow of force in the vehicle drivetrain (). An actual speed that is at least equivalent to a transmission input speed is monitored and an actuation pressure of the frictional shift element involved in the shift operation and/or a torque of the drive motor () is/are varied to change the actual speed to a nominal speed.

Method for operating a vehicle drivetrain

A process for monitoring a direction of drive from an automatic or automated vehicle transmission at near-zero vehicle speed via an engaged gear. A desired direction of drive of the transmission is determined from an engaged gear at the time the vehicle begins motion. An actual direction of drive is determined from the transmission and if different from the desired direction of drive, an error signal is produced. The process including determining the actual drive either from a sensed rotational direction of a transmission input shaft and a sensed rotational direction of a transmission output shaft or a sensed valve setting, a sensed pressure in an transmission electro-hydraulic control system or on a transmission shifting element or from a sensed direction of rotation of a transmission gearset element or from axial movement or force of a transmission constructional element.

Process for monitoring the direction of frictional drive from a vehicle transmission at near-zero vehicle speed

A method of operating of a drivetrain, having at least a drive motor and an automatic transmission with at least five shift elements, to improve a shift speed such that during a first upshift or a first downshift, at least one required shift element is prepared such that, when a synchronization point is reached, the successive upshift or the successive downshift can be immediately carried out. The method comprises the steps of requiring, at most, two of the at least five shift elements be disengaged and a remainder of the shift elements be disengaged for each gear for transferring one of torque and force; and one of increasing and decreasing a torque of the drive motor, relative to a torque of the drive motor derived from a driver's wish, during one of the first upshift or downshift and the successive upshift or downshift to assist with an overlapped implementation of the successive upshifts or the successive downshifts.

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Kressbronn, Germany

Christian Popp