Robert Boschgmbh

Hartmut Sandau

Holger Lueues

Werner Schumacher

Heinrich Kochendorfer

August Kraisel

Wilhelm Weigert

Erwin Gaub

Winfried Steinel

Klaus Ritter

An electro-hydraulic control device (,) for a hydraulic servo motor for controlling a volume flow is proposed, which is embodied as a 4/2 valve module. A blocking valve in accordance with seat valve technology between a motor connection (B) and a return flow (R) form a lowering element (,), while the associated unblocking member (,) is designed as a longitudinal slide (,), which controls the connection between an inflow connection (P) and a motor connection (A) and is actuated by a proportional magnet (,). After unblocking the blocking valve, its seat valve body (,) is mechanically taken along by the longitudinal slide (,), and the two volume flows are proportionally controlled via the lowering element (,) and the lifting element (,), so that a large switching capacity is achieved along with a construction with few leaks.

Electrohydraulic control device

A control device for a volume stream of a hydraulic working medium has a blocking valve having a seat valve body cooperating with a stationary main valve seat, a pre-control valve member arranged in the seat valve member and cooperating with a valve seat provided with the seat valve member, an actuating device with which the pre-control valve member is in an operative communication, a spring providing a force with which the pre-control valve member cooperates with the valve seat and controls a pressure in a pressure chamber formed in the seat valve member and a valve housing. The seat valve member is pressed against the main valve seat under the action of the pressure, a pressure chamber for a working medium is formed, a throttle point with a constant cross-section communicates the pressure chamber between the seat valve body and the valve housing constantly with the pressure chamber of the working medium, a variable throttle point connects the pressure chamber between the seat valve body and the valve housing with a container. The variable pressure point has a cross-section which is changeable by the pre-control valve member. The actuating device which cooperate with the pre-control valve member is formed as a proportional magnet mounted on the locking valve.

Control device for volume stream of hydraulic working medium

The control valve for keeping constant viscosity and temperature of a pressure medium in a hydraulic circuit includes a preliminary control valve which supports a temperature sensitive control element and adjustable throttling means including a throttling plunger controlled by the control element; a control slider arranged in the valve upstream of the preliminary control valve is provided with first throttling means for admitting pressure medium against the preliminary control valve to establish a bypass connection in addition to the main connection controlled by the slider; to avoid excessive temperature increase of the medium in the case of a damage of the control element, a temperature sensitive shearing pin is provided between the control element and the throttling plunger to cause an override of the plunger to a position in which an additional bypass connection is established which prevents throttling and thus temperature increase of the pressure medium.

Control valve

A pressure tank includes a hollow container which has an outlet for discharging fluid therefrom. The outlet is provided with a valve seat, for receiving a valve member which is slidably mounted in the container above the valve seat for respective movement between an open position, so that fluid in the container can flow therefrom through the outlet and a closed position so as to prevent discharging of fluid out of the container. A flexible partition is provided in the container, subdividing the interior thereof into a gas-containing compartment and into a liquid-containing compartment. The partition is displaceable on expansion of gas in the gas compartment, into an extended position immediately adjacent the outlet. An element is connected to the valve member, which element cooperates with the partition in the extended position of the same so as to prevent premature movement of the valve member into the closed position until the container is empty.

Valve for a pressure tank

A piston rod connected at one end to a piston slidably arranged in a cylinder projects with its other end through an opening in an end wall of the cylinder beyond the latter and a fork-shaped member is connected by a friction weld, that is without adding welding material or external heat, to the other end of the piston rod.

Cylinder-and-piston arrangement and method of manufacturing the same

A hydrostatic power steering system wherein the steering wheel can rotate a pilot pump which is connected with compartments at the opposite ends of a spool reciprocably received in a valve body having ports connected with a main pump, a reservoir, the chambers of a power cylinder whose piston is connected with the steering linkage, and with spaces defined by the valve body with two plungers disposed at the opposite ends of the spool. The spool is normally held in a neutral position by two centering springs which react against the respective plungers and bias two retainers into engagement with the spool. The plungers are connected to each other by a rod which is reciprocable in an axial bore of the spool. When the steering wheel is rotated in one direction, the pilot pump causes fluid to flow into one of the compartments whereby the spool is shifted to one of two operative positions and allows the main pump to supply pressurized fluid to one chamber of the power cylinder while the other chamber discharges fluid into the reservoir. If the steering wheel is rotated in the opposite direction, the main pump supplies pressurized fluid to the other chamber of the power cylinder while the one chamber discharges fluid into the reservoir. If the piston of the power cylinder is displaced in response to external influences, the spool moves to the one or the other operative position unless the steering wheel is held by the hands of the operator whereby the spool reassumes its neutral position. The chambers of the power cylinder receive pressurized fluid by way of the pilot pump.

Growing community of inventors

Schwieberdingen, Germany

Hartmut Sandau