Danfoss A/s

Sauer Danfoss Aps

Sauer-danfoss (nordborg) A/s

Carl Christian Dixen

Carsten Christensen

Knud Meldgaard Jensen

Svend Erik Thomsen

Thorkild Christensen

Siegfried Zenker

Brian Kongsgaard Nielsen

Richard Thomas Entwistle

Harry S Nissen

Kjeld Ravn

Steve Crow

Hans Jørgen Jensen

Flemming Thomsen

Steen Slot

Svend Giversen

Smari Johannsson

Henrik Kjer Kristiansen

Jan Maibøll Buhl

The invention concerns a hydraulic steering with a steering motor arrangement having at least one steering motor, and with at least two steering circuits, each having a steering valve that interrupts a path from a pressure supply to the steering motor arrangement in the neutral position and releases a path from the pressure supply to the steering motor arrangement on a movement out of the neutral position. It is endeavored to simplify the embodiment of such a steering. For this purpose, the steering valve () has two end positions, one on each side of the neutral position, in which positions a path from the pressure supply () to the steering motor arrangement () is interrupted.

Hydraulic steering

The invention concerns a hydraulic control () with a supply connection arrangement () having a high-pressure connection (P) and a low-pressure connection (T), a working connection arrangement having two working connections (A, B) connectable with a consumer, a control valve () with a valve element () between the supply connection arrangement and the working connection arrangement and a compensation valve (), which is located between the high-pressure connection (P) and the control valve () and is acted upon in the closing direction by a pressure between the compensation valve () and the control valve (). It is endeavoured to ensure the most favourable energy consumption possible. For this purpose, in the opening direction the compensation valve () is acted upon by a pressure of a selection device (), which optionally supplies the compensation valve () with a pressure control pressure or a flow control pressure.

Hydraulic control

The invention concerns a hydraulic valve arrangement () with a control valve module () comprising a supply connection arrangement with a high-pressure connection (P) and a low-pressure connection (T) and a working connection arrangement with two working connections (A, B) as well as a control valve () between the supply connection arrangement and the working connection arrangement. It is endeavored to improve the control behavior of the valve arrangement. For this purpose. it is ensured that the control valve module () has a return compensation valve () between the control valve () and at least one working connection (A, B).

Hydraulic valve arrangement

The invention concerns a hydraulic valve arrangement () with a working connection arrangement having a first working connection (A) and a second working connection (B), both working connections (A, B) being connectable with a hydraulic consumer (), a supply connection arrangement having a pressure connection (P) and a tank connection (T), a first valve arrangement with a first valve (), closing the pressure connection (P) or connecting it in a controlled manner with the first working connection (A) or the second working connection (B), a second valve arrangement with a second valve (), closing the tank connection (T) or connecting it in a controlled manner with the first working connection (A) or the second working connection (B), and a control arrangement controlling the first valve arrangement and the second valve arrangement. In such a valve arrangement, it is endeavoured to achieve improved operation behaviour. For this purpose, at least with one of the two valves () a working position can be set, in which the first and the second working connections (A, B) are connected with each other.

A hydraulic control system () has a hydraulic motor (), which is connected with a control valve () via two working lines (), the control valve () being connected with a low-pressure connection (T) and, via a compensation valve (), with a high-pressure connection (P), to ensure that a return compensation valve () is arranged in each working line, each return compensation valve () having a nominal flow line (), which extends unintersectedly in relation to the nominal flow line () of the compensation valve ().

Hydraulic control system

A hydraulic valve arrangement includes a control valve ( ), which, in a first operating position ( ), connects a motor connection ( ) with a pump connection, in a second operating position ( ), connects a motor connection with a tank connection, and, in a locking position ( ), disconnects the motor connection ( ) from the pump and tank connection. A locking valve ( ) is coupled between the control valve ( ) and the motor connection ( ), dividing the motor line ( ) into a first section ( ) allocated to the control valve ( ) and a second section ( ) allocated to the motor connection ( ). For the locking valve ( ), a pressure release valve ( ) in the shape of a seated valve is provided that is fixed to the housing thereby improving control accuracy.

A hydraulic system with a pressure source controllable via a load sensing signal, a pressure sink, at least two working sections, each having a hydraulic consumer and a control valve with a load sensing signal connection and at least one back-pressure valve arranged in a tank pipe between the control valve and the pressure sink. In such a system the pressure required from the pump in the neutral position must be as low as possible. On the other hand, however, oscillations should not occur, when an external force acts on another hydraulic consumer in the neutral position of a control valve. In the neutral position of the control valves the load sensing signal connection is therefore connected with the pressure sink via an auxiliary tank pipe by-passing the back-pressure valve.

Hydraulic system

The invention concerns a control valve with a housing, having a pump connection, a tank connection device, a working connection device and a load pressure connection device, each connected with an opening device in a control surface, and with a slide, arranged movably in the housing and co-operating with the control surface, the slide having grooves and/or channels, so that it connects or separates predetermined opening devices with/from each other. In such a control valve the tightness must be improved. For this purpose an additional auxiliary tank connection device is provided, which is connected with an auxiliary tank opening device in the control surface. The slide has an auxiliary tank pipe or groove, which, in its neutral position, connects the auxiliary tank opening device with the load pressure opening device.

Control valve

Axial piston machine

A control system for a two way acting hydraulic servomotor wherein the servomotor is connected in the diagonal of a bridge circuit that includes four magnetic valves with a pair of the valves being normally open in a non-energized condition being connected to the one end of the servomotor and to the container and a second pair of the valves being normally closed in a deenergized condition being connected to the opposite end of the servomotor and to a pressure source. Circuitry provides pulse trains that are modulatable to control the operation of the magnetic valves and thereby the application of pressurized fluid to the opposite ends of the servomotor.

Control means for a hydraulic servomotor

The invention relates to a hydraulic system of the type in which a pump unit supplies pressurized fluid to a plurality of bidirectional servomotors. The system includes at least two modules each of which includes a bidirectional servomotor, a control valve and a compensating valve on the upstream side of the control valve. The pump unit includes a feedback loop having a throttle and a pump pressure regulator in series. Each of the modules has a sensing conduit connected to a common header which is operable to sense load pressure at the upstream side of the control valve for controlling the compensating valve in accordance with the load pressure. A pressure divider comparator valve is connected to the header and a point in the feedback loop between the throttle and the pump pressure regulator. The comparator valve is operable to compare the pressure at such point with the pressure in the header and to bleed pressurized fluid from that point to the tank to equalize the pressures.

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Sydals, Denmark

Carl Christian Dixen