Zf Friedrichshafen Ag

Zf Batavia L.l.c.

Zf Friedrichshafeb Ag

Ralf Vorndran

Wolfgang Danz

Patrick Speicher

Andreas Piepenbrink

Andreas Schwenger

Udo Gillich

Friedrich Reiter

Hubert Konig

Andreas Salm

Thomas Fichtinger

Anton Welte

Hans Peter Stoll

Rolf Karrer

A device, in a continuously variable belt transmission system, for guiding a conical pulley () of a variator on a variator shaft (). The moveable conical pulley () is fitted onto two bearing sections () of the variation shaft (). At least one cylindrical pin (), which is fitted into an axial guide grove () in the variator shaft () and an axial guide groove () of the movable conical pulley (), is provided to transfer torque between the movable conical pulley () and the variator shaft ().

Device for guiding a moveable conical pulley disc of a CVT variator

The invention relates to a method for manually stipulating the transmission ratio of a continuously variable transmission (CVT) for a motor vehicle. The CVT comprises a control device, a shifting or selecting device, a starting element and a variator for adjusting the transmission ratio which is driven, in particular, by an internal combustion engine. The control device processes input signals derived from a driver-vehicle system within the framework of an operational strategy for stipulating the transmission ratio, the rotational speed of the drive motor or a variator input rotational speed. In a first automatic operation mode, the operational strategy automatically selects the transmission multiplication. In a second manual operational mode, the driver can directly intervene, via the shifting or selecting device, in the selection of the transmission multiplication. The invention provides, in the second mode of operation, that preset, continuous and vehicle speed-dependent engine rotational speed progressions or variator input rotational speed progressions or transmission ratio progressions can be manually selected. The progressions are displayed as curve traces within upper and lower limits of the adjustment range such that vehicle stand still and a highest possible speed of the vehicle can be attained in each progression.

Method for manually stipulating the transmission ratio of a continuously variable transmission (CVT)

Within the scope of the method for controlling the engine rotational speed via the torque converter lock-up clutch during the starting and stopping phases of a motor vehicle having a continuously variable transmission combined with other elements of the drive train, the closing and opening of the torque converter lock-up clutch are used as implicit function so as to ensure optimum comfort via the most asymptotic adjustment possible of the rotational speeds gradients of engine and turbine during starting and by a soft, defined separation of the speed characteristic curves of the engine and turbine during stopping. When the vehicle is standing still the forward clutch is moved into standstill disengaged mode so that the torque converter lock-up clutch can be fully closed.

Engine speed control via the torque converter lockup clutch of a continuously variable drive

In a method for controlling the multiplication for a continuously variable transmission with electrohydraulic control by means of a control loop having a linear PID controller with the specified multiplication of the variator iv_soll as command variable, the actual multiplication iv as regulating variable and the multiplication changing speed as correcting variable, the correcting variable delivered by the PID controller is limited to limiting values determined by the design for an upshift and downshift wherein said limiting values are calculated form the limits determined by construction and from the operating-point dependent limits determined by volume flow and the intersection of both admissible intervals determined by construction and by volume flow is defined as admissible multiplication changing speed range.

Method for determining adjusting speeds in a continuously variable transmission

Proposed is a hydraulic scheme for a stepless automatic transmission of a motor vehicle. The system has a variator which is controlled by a hydraulic regulating apparatus, and which possesses a cooler ( ) placed in an oil lubricating/cooling circulation from which a line ( ) leads from cooler ( ) to an oil sump ( ). An orifice ( ) is located after the cooler ( ) in the line ( ), in the direction of oil flow, the oil flow through the orifice ( ) is controllable as a function of the speed of rotation of the drive motor of the vehicle and/or the speed of the vehicle.

Hydraulic system

An automatic transmission having at the input a starting element ( ), a reversing set ( ), a first electronic control unit ( ) and a cone pulley ( ) fixedly supported on one primary shaft ( ) and axially thereto a hydraulically adjustable cone pulley ( ), both pulleys forming a primary variator part ( ). In addition there is a cone pulley ( ) fixedly supported on a secondary shaft ( ) and axially thereto a hydraulically adjustable cone pulley ( ) together forming a secondary variator part ( ) wherein a belt-type organ ( ) between the cone pulleys ( ) drivingly connects the primary variator part ( ) with the secondary variator part ( ). The starting element ( ) is a dry running disc clutch whose disc is non-rotatably connected with the primary shaft ( ) and interacts in a clutch housing ( ) with a non-rotatably but axially movably disposed pressure plate ( ) actuated via axial bearings ( ) by a non-rotating actuator ( ), the clutch housing ( ) being non-rotatably connected with an input shaft ( ) of a prime mover ( ). The purpose is to reduce the rotating masses and to improve the adjustment of the variator ( ).

Automatic transmission

The invention concerns a process for evaluating a driving dynamic request of a driver for the driving strategy of one of an automatic or automated transmission of a motor vehicle. It is proposed to calculate an accelerator pedal stroke, from the accelerator pedal actuation, which is supplied to the driving strategy as an input parameter to the driving strategy equivalent to the driving dynamic request. To this end, a rough value of the accelerator pedal stroke is calculated, especially by subtraction of the accelerator pedal position at beginning of the accelerator pedal movement from the accelerator pedal position, from accelerator pedal values which are in fixed event-dependent ratio to each other. The accelerator pedal stroke results from an event-dependent filtering of the rough value of the accelerator pedal stroke during which a filtering function starts at the end of the accelerator pedal movement, especially when the accelerator pedal position is constant over a presettable time. The rough value of the accelerator pedal, existing at this moment, breaks down by a presettable time function.

Process for evaluating the driving dynamic request of the driver for the driving strategy of an automatic/automated transmission

Within the scope of the method for including the temperature in the calculation of the definite, operating-point dependent maximum and minimum adjustment speeds in a continuously variable belt-drive transmission, the actual limiting values for the maximum possible adjustment gradient are continuously calculated in every operating state by a physical-mathematical pattern wherein the hydraulic routes of the variator, the clutches integrated in the transmission and the lubrication are modeled as laminar inserts and the route of the control unit leakage as coupled laminar and turbulent hydraulic transmission elements.

Method of calculating for the speed control of a CVT

In the process according to the invention for predetermining the ratio of a continuously variable transmission (,), a dynamic driving range is generated. The actual, minimum and maximum acceleration (a_akt, a_min, a_max) is calculated. Further detected is the driver's wish to accelerate or to decelerate (a_fwu) and an acceleration (a_vorg) is determined. Also calculated is a change of ratio per time unit of the continuously variable transmission (iV_pkt), which is guided by the engine speed of rotation during adjustment of the continuously variable transmission (,).

Process for determining the operating point of a continuously variable transmission

The invention relates to a method of adjusting the transmission ratio of a continuously variable gear. The position of a current operating point (B_akt) in a predetermined driving range is constantly adjusted in accordance with the driving situation. The position of the operating point is also determined by range boundaries (UG, OG) which can be varied in accordance with the driving resistance and the driver's manner of driving. The method is characterized in that it simplifies development and application.

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Eriskirch, Germany

Ralf Vorndran