Abstract: A shift element sub-assembly for a transmission comprises two axially adjacent shift elements (2, 3) that are located in a transmission housing (1), in addition to a common disc carrier (4) for receiving external discs (20, 21) or internal discs of both shift elements (2, 3). The discs of both shift elements (2, 3) lie axially adjacent in the interior of the disc carrier (4) and are separated from one another by a central partition (40) of the disc carrier (4). Each shift element (2, 3) has a piston (23, 33) and a closing pressure chamber (24, 34), located in the vicinity of the front faces (41, 43) of the disc carrier (4), for hydraulic actuation. Each shift element (2, 3) has at least one resetting element (27, 37, 39) for resetting the piston, the element being located in the disc carrier (4) radially above the discs of the respective shift element (2, 3).

Abstract: Within the framework of a method for reducing the thermal stress of starting shift elements in automatic gearboxes or automated manual gearboxes with at least two shift elements in the force flow, on starting, besides a first shift element at least a further shift element is used to take up at least part of the slippage.

Abstract: A device for the control of a hydraulically actuated clutch (1) of an automatic transmission of a motor vehicle having a slide-valve mechanism (3) is proposed, in which a valve piston (4) can move between a first working space (7) which can be pressurized via a control line (8) with a control pressure (p_MV) adjustable by means of an electrically operated actuator (9) and a restoring space (10) containing a restoring spring (11) that acts on the valve piston (4). The valve piston (4) is made with several piston sections (4A, 4B) that delimit a pressure space (12) which is connected via a line (13) to a clutch space (2) of the clutch (1) and which, depending on the position of the valve piston (4), has a connection to a pressure supply line (14) delivering a system pressure (p_sys) or to a pressure-relief line (15).

Abstract: The hydraulic control device for accommodating electromagnetic actuators and hydraulic valves, which is inserted in an automatic transmission for a motor vehicle, has at least one seal which is made of an aluminum support which has a thickness in the range of from 1 to 2 mm and is coated with a material at least on one side; the material, having a layer thickness in the range of from 100 to 180 &mgr;m, has a hardness in the range of from 20 to 120 Shore A and on its free surface is provided with a profiling having a depth in the range of from 20 to 50 &mgr;m.

Abstract: A device for control of a hydraulically actuatable shifting element of a motor vehicle transmission, especially of a powershift transmission, comprising one clutch piston which defines, with a first surface, a hydraulically pressurizable piston space and, with a second surface of different size, a hydraulically pressurizable reset space and comprising a slide valve system which has a first clutch valve associated with the piston space, a second clutch valve associated with the reset space and a holding valve associated with the reset space.

Abstract: A device to allow for emergency operation of an automatic-transmission motor vehicle, having a monitoring device to monitor pre-determined operating parameters, a diagnostic device to detect faults, a control device to activate an alternative function, and an output device by means of which the fault may be presented to the driver. The control device provides the driver an emergency operation capability while providing an alternative function depending on the degree of the fault.

Abstract: The invention relates to a vibration damper for damping fluid vibrations in a hydraulic system, especially in a hydraulic control circuit for a motor vehicle gear box with an elastically deformable damper element (31), According to the invention, the vibration damper is provided with a separate sealing element (32) which guarantees the functioning of the hydraulic system in the event of a breakdown e.g. the damper element (31) bursting.

Abstract: Electronic-hydraulic control device of an automatic automobile transmission in which all of the solenoid valves (12) and pressure control valves (6, 7, 8, 9, 10, 11) are de-energized when the electronic control device fails and in which a lower gear, preferably third gear, is automatically selected when a lower gear has been previously engaged, and a higher gear, preferably fifth gear, is selected when a higher gear has been engaged previously. The control valves (20, 21, 23) have surfaces of different dimensions that can be controlled jointly or individually to permit a variety of valve characteristic curves.

Abstract: The invention relates to a parking brake system for a gearbox of a motor vehicle. An electric engagement is provided between the operating device in the interior of the motor vehicle and the parking brake. The inventive system comprises a spring-type cylinder (9) for activating the parking brake and a pressure-controlled release device of the parking brake. According to the invention, the release device (10) is impinged upon a gearbox-independent negative pressure when the parking brake is released. Said pressure is preferably taken from the suction system (15) of the internal combustion engine pertaining to the motor vehicle or from a negative pressure brake booster pertaining to the motor vehicle.

Abstract: An electronic-hydraulic control device of an automatic automobile transmission with frictional clutches or brakes that can be hydraulically operated to shift individual gears (A, B C, D, E), and with an electronic control device (32) which is electrically connected with a lever inside the motor vehicle, shifting gears depending on the preselected lever position and certain parameters of the combustion engine and transmission. If the electronic control device (32) thus de-energizing all solenoid valves (11, 12, 15, 16), an emergency gear is maintained during forward travel until the combustion engine is shut off after which the parking mechanism is automatically engaged, and if the electronic transmission control (32) fails during rearward travel, all clutches or brakes are depressurized and the parking mechanism is automatically engaged.

Abstract: A method is proposed for the control and regulation of a drive system of a motor vehicle having one electronic transmission control for an automatic transmission and connected therewith an electronic engine control for a prime mover. In a coasting operation of the drive system, during a change over of a transmission element from an open to a closed or a slipping state during a coupling procedure of the transmission or a regulation procedure of the transmission element, rotatory masses of the engine are regulated and accelerated under control so that a vehicle deceleration is less than a presettable tolerance value.

Abstract: Parking brake, notably for automatic transmissions of motor vehicles, which is released via hydraulic pressure acting on a spring accumulator (3) and which is additionally held in the released state by a locking system (13) is actuated by a magnet (5) through which a current flows. The locking system (13) is kept activated and thus the parking brake released until the magnet (5) in the position in which the locking system (13) is actuated, has a power consumption lower than necessary for loading the locking system (13).

Abstract: Pressure regulating valve comprising a connection for a pressure line (P), a connection for a working line (A), a connection for an outlet line (T) communicating with the ambient pressure and at least two diaphragm stages with defined or definable drag, the two diaphragm stages being connected to each other in a variable manner and subject to mechanical or hydraulic action according to the principle of the hydraulic half bridge. The two variable diaphragm stages are provided as the inlet and outlet diaphragms of a pressure regulating chamber (7) and each has a sealing element, said sealing element (5) of the inlet diaphragm (3) is designed as ball, or calotte, ortruncated cone, or cylinder and/or the sealing element of the outlet diaphragm is designed as ball, or calotte, or truncated cone, or cylinder.

Abstract: Pressure regulating valve comprising a connection for a pressure line (P), a connection for a working line (A), a connection for an outlet line (T) communicating with the ambient pressure and at least two diaphragm stages with defined or definable drag, the two diaphragm stages being connected to each other in a variable manner and subject to mechanical or hydraulic action according to the principle of the hydraulic half bridge. The two variable diaphragm stages are provided as the inlet and outlet diaphragms of a pressure regulating chamber (7) and each has a sealing element, said sealing element (5) of the inlet diaphragm (3) is designed as ball, or calotte, or truncated cone, or cylinder and/or the sealing element of the outlet diaphragm is designed as ball, or calotte, or truncated cone, or cylinder.

Abstract: A method is proposed for the control and regulation of a drive system of a motor vehicle having one electronic transmission control for an automatic transmission and connected therewith an electronic engine control for a prime mover. In a coasting operation of the drive system, during a change over of a transmission element from an open to a closed or a slipping state during a coupling procedure of the transmission or a regulation procedure of the transmission element, rotatory masses of the engine are regulated and accelerated under control so that a vehicle deceleration is less than a presettable tolerance value.

Abstract: A method for pressure adaptation is proposed for an automatic transmission. The gear shifts here are carried out as overlapping gear shifts with a first opening (K1) and a second closing (K2) clutch, the overlapping gear shift consisting of a first and a second phase. During the first phase, a banking of the transmission input rotational speed (nT) is adjusted. The invention proposes that upon issuance of the shift command, a time period (t2) is determined until the transmission input rotational speed has reached the banking value (dn). This is compared with a predetermined time (tAD) during which a difference is obtained which provided with a sign is totaled in a summation memory. An adaptation value is stored in a correction value memory when the summation memory exceeds a limit value. As consequence of this, the disconnection pressure level (pAB) of the first clutch (K1) is adapted in subsequent gear shifts.

Abstract: Device for releasing in case of emergency a security device for a motor vehicle having an automatic transmission (1) in which the parking lock of the automatic transmission (1) is released by actuating a towing device (2) accessible from outside the motor vehicle and the axial movement associated therewith of the operative connection (3) between the towing device (2) and the release device (10) on the automatic transmission (1). By a stop (12) of the towing device (2) the release device (10) remains activated until the stop (12) on the towing device is deactivated.

Abstract: A method for determining parameters of an electrohydraulically controlled automatic transmission (4) by, on a final test bench, successively initiating transmission gearshifts. During gear changes the parameters of the automatic transmission are determined from measuring values transmission input/transmission output speeds (10, 12) and transmission input/transmission output moments (11, 13).

Abstract: In an automatic transmission in which the electronic control instrument (13) detects, outside the circuits, a fault in the input values (18 to 20), the couplings and the brakes (A to F). When a fault is present for an extended period, the electronic control instrument (13) detects a symptom and switches to a replacement gear. Hereby maximum driveability is ensured without a diagnosis entry.

Abstract: The proposal is for a process for controlling an automatic transmission in which, on the basis of a speed-change demand, an electronic control device determines a mode of changing (F1, F2, F3), compares an existing operation point with a theoretical operation point in which the theoretical operation point depends upon the mode of changing and selects a first or second change range.