Danfoss A/s

Sauer Danfoss Aps

Danfoss Power Solutions Aps

Sauer-danfoss Holding A/s

Sauer-danfoss (nordborg) A/s

Danfoss Fluid Power A/s

Sauer-danfoss (nordberg) A/s

Carsten Christensen

Siegfried Zenker

Thorkild Christensen

Carl Christian Dixen

Svend Erik Thomsen

Welm Friedrichsen

Erik Haugaard

Martin Raadkjaer Joergensen

Harry S Nissen

Verner Smidt

Lasse Nicolai Langmaack

David Collins

Xavier Mabit

Helge Joergensen

A hydraulic system of a vehicle is provided, said system including: a first hydraulic circuit () having a first pressure source () and at least a first hydraulic consumer (), a second hydraulic circuit () having a second pressure source () and at least a second hydraulic consumer (), connecting means () allowing a flow of hydraulic fluid at least from said first hydraulic circuit () to said second hydraulic circuit (), and control means () for controlling operation of said hydraulic consumers (). Such a hydraulic system should allow safe operation of a vehicle with low energy consumption of the hydraulic system. To this end said control means () are connected to summation demand means (), said summation demand means () controlling flow of hydraulic fluid from at least said first hydraulic circuit () to said second hydraulic circuit (), said summation demand means () being connected to operation mode signal means () outputting an operation mode signal indicative of an operation mode of said vehicle, wherein said summation demand means () allow or block flow of hydraulic fluid from one hydraulic circuit () to another hydraulic circuit () in dependency of said operation mode signal.

Hydraulic system of a vehicle

The invention concerns a valve arrangement () comprising a flow path () connecting an inlet () and an outlet (), a closing means () arranged in said flow path (), a resetting means and a first pressure in a first pressure chamber () acting in a closing direction on said closing means (), a pressure of said outlet () and a second pressure in a second pressure chamber () corresponding to a pressure of said inlet () when said closing means () is closed acting in opening direction on said closing means (), said first pressure chamber () being connectable to the outlet () via an auxiliary valve (). It is intended to keep small a pressure pulse when opening the valve arrangement (). This is achieved in that the closing means () having a first opening state (A) and a second opening state (B), a flow resistance of said closing means () in said first opening state (A) being larger than a flow resistance of said closing means in said second opening state (B).

Valve arrangement

The invention concerns a brake valve arrangement of a vehicle having a trailer coupling and at least one controllable hydraulic consumer, with a brake valve (). It is endeavored to provide a similar embodiment of a vehicle with such a brake valve arrangement. For this purpose, the brake valve () is combined with at least one control valve () controlling the hydraulic consumer into forming a valve block () having several valve modules.

Brake valve arrangement

The invention concerns a hydraulic valve arrangement with a supply connection arrangement, which has a high-pressure connection (P) and a low-pressure connection (T), a working connection arrangement, which has two working connections (A, B), which can be connected with a consumer, a directional valve and a compensation valve arranged between the directional valve and the supply connection arrangement, the pressure outlet of the compensation valve being connected with a pressure inlet of the directional valve. It is endeavoured to avoid dangerous situations, which occur because of uncontrolled pressures. For this purpose, it is ensured that the compensation valve has a relief outlet, which can be connected with the pressure outlet.

Hydraulic valve arrangement

The invention concerns a hydraulic dual circuit steering system with first circuit having a first control unit and a first steering motor connected with the control unit via working connections, a second circuit having a second control unit and a second steering motor connected with the control unit via working connections, a changeover valve, which in a first position activates the first circuit and deactivates the second circuit and in a second position activates the second circuit and deactivates the first circuit. To improve the steering behaviour, in the first position of the changeover valve the working connections of the second circuit and in the second position of the changeover valve the working connections of the first circuit are connected with a pressure source.

Hydraulic dual circuit steering 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.

The invention concerns a hydraulic valve arrangement with locking function. It has a control valve ( ), which in two operating positions ( ) connects one motor connection (A) with a pump connection and a second motor connection (B) with a tank connection and vice versa, and in a locking position ( ) separates both motor connections (A, B) from pump and tank connection. Further, there are two lock valves ( ), each connected between the control valve ( ) and one of the motor connections (A, B). This valve arrangement is characterised in that for each lock valve ( ) a pressure release valve ( ) is provided, whose operating member ( ) is loadable in the closing direction by a first chamber pressure and an additional force acting in a first chamber ( ) and in the opening direction by a control pressure acting in a second chamber ( ), and that the control pressure in dependence of the position of the control valve ( ) has a lower value, which is equal to the first chamber pressure, and an upper value, which exceeds the first chamber value by such a value that the oppositely acting closing force is overcome. This gives a very high degree of operation safety.

Hydraulic valve arrangement with locking function

A hydraulic valve arrangement with locking and floating function, with a control valve (,), which, for two operating positions (,) connects one motor connection (A) with a pump connection and a second motor connection (B) with a tank connection and vice versa, in a floating position (,) connects both motor connections (A, B) with the tank connection and in a locking position (,) separates both motor connections (A, B) from the pump and tank connections. Further, there are two closing valves (,), each being connected between the control valve (,) and a motor connection (A, B) and each having a piston loaded by a spring and limiting a spring chamber, the spring chambers being pressure releasable. Characteristic of this valve arrangement is that lifting valves (,) are provided for the pressure release, which valves are operated by a control pressure depending on the position of the control valve (,). This improves the operating reliability.

Hydraulic valve arrangement with locking and floating function

Hydraulic control system for work vehicles

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

A hydraulic control valve for controlling flow between a pump, a hydraulic device, and a vessel containing hydraulic fluid. The control valve has an elongated valve slide which is slidably mounted in an elongated valve housing. The valve has three positions, a central neutral position, a float position axially offset in one direction from the neutral position and a constant pressure position axially offset in the opposite direction from the neutral position. In the neutral position, flow of hydraulic fluid to the hydraulic device is inhibited. In the float position, connection is such that a raised device, such as a hydraulically operated bucket, is lowered slowly by gravity until it rests on the ground or another object. In the constant pressure position, the valve connects pump pressure to the load sensing circuit to facilitate, for example, shaking of a bucket of a piece of earth moving equipment.

Hydraulic control valve

There is provided control apparatus for controlling fluid flow between a bidirectional motor, a pump and a container, and includes a control valve that has a slide operative between neutral and first and second operative positions. A compensating valve is provided in the supply conduit that holds the upstream pressure drop at the control valve substantially constant and is controlled by load pressure sensing circuitry. The load pressure circuitry includes two branches that are connected through a change over valve to the compensating valve. There is provided an over pressure valve and a throttle point in each branch, each branch being connected to a load pressure sensing orifice of the control valve housing and fluidly connected through the slide to one of the housing motor orifices, the one depending upon whether the slide is in its first or in its second position. The circuitry permits the actuating pressure for operating the motor in one direction to be different from that for operating it in the other direction.

Growing community of inventors

Broager, Denmark

Carsten Christensen