Mannesmann Rexroth Corporation

Mannesmann Rexroth Ag

Winfried Rub

Rainer Biener

Heinz Schulte

Ludwig Muncke

Richard Rauscher

Hydraulic device for controlling a hydraulic-fluid flow

Hydraulically actuatable directional control valve

A safety circuit for a servo-hydraulic regulating system for the hydraulic control and actuation of load units, such as operating tools on utility vehicles and agricultural machines. The controlling of the load unit is effected via a proportional valve which is actuated in dependence upon a pair of output signals of a measuring bridge in such a way that, in the event of a balanced measuring bridge, it assumes a neutral setting in which the operating line running to the load unit or emanating from the load unit is blocked. In order to prevent the lifting gear from executing a regulating reaction if the measuring bridge is out of tune when the servo-hydraulic regulating system is switched on, a safety valve arrangement is provided in the operating line. Depending on at least one control signal determined by the setting of the proportional valve, when the regulating system is switched on, the operating line is blocked until, via the at least one control signal, the balance of the measuring bridge has been registered.

Safety circuit for a servo-hydraulic regulating system

A process is described for application of pressure on setting mechanisms of transmission elements, e.g., band brakes or disk clutches, of an automatic transmission, particularly of the transmission system of a vehicle. In the process the control pressure applied to the setting mechanism is varied in dependence on the operating conditions. In order to eliminate transition errors and improve adaptation of the meshing behavior of the switching element, the slide of the switching element is regulated at a value adapted to the operating condition involved of the transmission and/or the vehicle. Apparatus for the implementation of the process is also described, as well as a hydraulic control system for supplying the operational chamber of a setting mechanism at a transmission element, which operational chamber has a continual leakage. In this regard, a valve device, by which the operational chamber can be rapidly filed by activation of the setting mechanism, is installed parallel to a rapid-response control valve, with which the pressure force of the transmission element parts can be influenced in a targeted manner. In this manner, it is possible for driver to feel a spontaneous reaction of the vehicle when activating the clutch or an autotmatic lever for switching between forward and reverse operation, without thereby detrimentally affecting the sensitivity and reaction time of the control valve.

Process and apparatus for regulating pressure application of setting

A control valve apparatus is described which is intended for selective transmission of pressure to at least two pressure spaces. A magnetic control device is provided for selectively applying a hydraulic system pressure to the respective pressure spaces. As another function, the apparatus may simultaneously depressurize the two pressure spaces through the application of a control pressure to the control valve apparatus. To minimize the required installation space and the manufacturing cost, the control valve apparatus is comprised of a single control valve, the control piston means of which can be exposed to the control pressure against the force of a restoring device and can be moved into intermediate control positions by means of the magnetic control device.

Multi-way control valve apparatus

Growing community of inventors

Neustadt/Main, Germany

Winfried Rub