Zf Friedrichshafen Ag

Bernd Doebele

Martin Miller

Norbert Wiencek

Josef Bader

Karl-Fritz Heinzelmann

An automated group transmission having a multi-stage main transmission (HG), a splitter group (VG) connected upstream from the main transmission (HG) and a two-stage range-change group (BG) connected downstream of the main transmission (HG), such that the splitter group (VG) is connected, via a controllable separator clutch, to a drive motor. The main transmission (HG) and the range-change group (BG) are of either a synchronized or an unsynchronized design and the shifting clutches of two respective transmission ratio steps, in at least one of the partial-transmissions (VG, HG, BG), are respectively combined in a common shifting packet with two shift positions and a neutral position. To speed up most range shifts, it is provided that in the main transmission (HG) the shifting clutches associated with the lowest transmission ratio step (G) and with the highest transmission ratio step (Gor G) are combined in a common shifting packet (Sor S).

Automatic group transmission

A method for shifting gears of an automatic transmission of a vehicle, by way of primarily form-locking shifting elements, while driving with or without utilization of a clutch depending on a decision made by a decision device which, in the presence of certain basic conditions, causes disengagement of a starting gear without disengaging the clutch, and subsequently reads in data about the size and the progression of a quantity correlating closely with the rotational speed of an output shaft of the automatic transmission and, with inclusion of this data, determines the shifting mode for engagement of the target gear.

Method for carrying out a shift of gears of an automatic transmission

A method for controlling shifts in an automated group transmission that comprises a multi-stage main transmission, a multi-stage splitter group connected upstream from the main transmission and a multi-stage range-change group connected downstream from the main transmission. The method includes the steps of disengaging the separator clutch to relieve the load of the motor; shifting range-change group to neutral and bringing the speed of the motor to the synchronous speed of the target gear; braking the main transmission and the splitter or upstream group via a transmission brake; changing the transmission ratios in the main transmission and in the splitter group; synchronizing the range-change group by partially engaging the separator clutch; engaging the desired transmission ratio in the range-change group; and simultaneously increasing the load on the drive motor and fully engaging the separator clutch.

Shift control method for an automatic group transmission

A method for controlling an automated friction clutch arranged in a drive train of a motor vehicle in the force flow between a drive engine () and a drive transmission (), which is configured to close passively by spring pressure and can be disengaged and engaged by way of a pressure-medium-actuated clutch actuator (), such that the actuation position x_K of the clutch actuator () or of an associated transmission element is determined and used for controlling the friction clutch (). To improve the accuracy and reliability of the clutch actuation it is provided that in addition, an actuating pressure p_K of the clutch actuator () is determined and that a required change of the clutch torque M_K to a new nominal value M_K_soll takes place under pressure control, in that the actuating pressure p_K of the clutch actuator () is set to a nominal value p_K_soll which corresponds to the nominal value M_K_soll of the clutch torque M_K.

Method for controlling an automated friction clutch

The present invention relates to a method for overcoming tooth butt conditions (ZaZ) when engaging gears in transmissions. A sensitive adjustment of the clutch to apply torque for rotating the drive shaft of the transmission in order to overcome tooth butt conditions has certain limits because of the proportion of the power required and desired for making said sensitive adjustment. This may cause unpleasant jerking of the vehicle or a clearly audible locking noise of the involved positively connected elements and undesired mechanical stress to said elements. The method according to the present invention provides a remedy due to the fact that during each shifting process, regardless of the occurrence of a tooth butt condition, the clutch is brought into a position allowing minimum predetermined torque transmission to the drive shaft of the transmission, and this torque is supported on a transmission brake, which is often already available. Due to its substantially smaller size, the transmission brake can much more quickly and accurately adjust a desired net torque curve and torque progress on the drive shaft of the transmission when a tooth butt condition occurs and thus make it significantly easier to overcome the tooth butt condition.

Method for overcoming tooth butt conditions when engaging gears in transmissions

A method for controlling an actuating device in an automated shifting system of a motor vehicle. The position of the actuating device is determined by a path measurement system. The actuating device can be controlled by a pressure regulation device, including a pressure medium reservoir, at least two pressure lines and a switching valve for connecting a first pressure line to a pressure medium line leading to the pressure chamber of the actuating device, and a pressure regulating device for adapting the pressure level of the main pressure line to the control pressure level of the actuating device. By appropriately controlling the pressure regulation device before the piston of the actuating device moves in the intended direction, it is moved in the direction opposite to the intended movement direction. When this movement direction is registered the movement direction is changed to the intended movement direction.

Method for activating an actuating means

A method for controlling an automatic transmission, which allows changing a gear change and downshifting with minimal interruption of traction while the phase of reduction of the drive torque of the drive motor, the phase interruption of the frictional connection phase in the automatic transmission and the phase of rotational speed adjustment in the transmission input shaft are designed for a suitable target rotational speed such that they at least partially overlap. Upon interruption of the frictional connection in the automatic transmission, the drive motor transmits a drive torque to the input shaft of the automatic transmission, via the main clutch, which adjusts the rotational speed of the input shaft of a transmission to the synchronous speed of the new gear.

Process and device for controlling a gearsift of an automatic gearbox

A method for detecting a rotational direction of the secondary side of a starting clutch in a motor vehicle string comprising the steps of determination of the primary speed of rotation of the primary side and of the secondary speed of rotation of the starting clutch. If the secondary speed of rotation is greater than the primary speed of rotation, an actuator operates in a closing direction, whereby the degree of closure of the starting clutch is adjusted to be dependent upon the acceleration of the secondary speed of rotation. A specified value for a rotational speed of the driving motor is produced which represents the secondary speed of rotation. To the extent that this value exceeds the value of the primary rotational speed, the rotational speed of the motor is regulated to the specified value. If the primary and secondary rotational speeds are equivalent within a preselected period of time, then detecting the same rotational direction for the primary and secondary sides of the starting clutch. If the rotational speed of the primary side of the starting clutch lies below the idling speed of rotation, detecting different rotational directions for the primary side and the secondary side of the starting clutch.

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Salem, Germany

Bernd Doebele