Danfoss A/s

Sauer Danfoss Aps

Sauer-danfoss (nordborg) A/s

Danfoss Fluid Power A/s

Sauer-danfoss (nordberg) A/s

Danfors A/s

Thorkild Christensen

Siegfried Zenker

Svend Erik Thomsen

Johannes V Baatrup

Carsten Christensen

Poul H Pedersen

Poul Erik Hansen

Welm Friedrichsen

Carl Christian Dixen

Tage Christiansen

Harry S Nissen

Helge Jorgensen

Poul Erik Termansen

The invention concerns a hydraulic valve arrangement () with a supply connection arrangement comprising a high-pressure connection (P) and a low-pressure connection (T), a working connection arrangement comprising two working connections (A, B), which can be connected to a motor (), a directional valve arrangement () located between the supply connection arrangement (P, T) and the working connection arrangement (A, B), and a compensation valve () acted upon in a first activation direction by a pressure in a first pressure chamber (), which is connected to a load-sensing pipe (LS), and, if required, by a spring (), and in a second activation direction opposite to the first activation direction by a pressure downstream of the directional valve arrangement (), said pressure acting in a second pressure chamber (), the compensation valve () having an inlet () and an outlet (). In connection with a post-compensated valve, it is endeavored to adjust the load pressures at the working connections (A, B) in dependence of the direction. For this purpose, each working connection (A, B) is connected to a control system, which amplifies the effect of the pressure in the first pressure chamber () on the compensation valve () in dependence of a pressure ruling at the working connection (A, B).

Hydraulic valve arrangement

The invention concerns a hydraulic valve arrangement () with at least two valve modules (-), each having a supply channel arrangement with a high-pressure channel () and a low-pressure channel (), a working connection arrangement with at least one working connection (A, B), one directional valve arrangement () between the supply channel arrangement () and the working connection arrangement (A, B) and a compensation arrangement (), which is acted upon by a pressure in a load-sensing arrangement. It is endeavored to increase the number of control possibilities. For this purpose, the load-sensing arrangement of at least one valve module (-) has a pressure influencing arrangement (-) that differs from a pressure influencing arrangement (-) of a load sensing arrangement of another valve module (-).

The invention concerns a hydraulic valve arrangement () with several valve modules (-), each having a supply channel arrangement with a high-pressure channel () and a low-pressure channel (), a working connection arrangement with at least one working connection (A, B), a directional valve arrangement () between the supply channel arrangement and the working connection arrangement and a compensation arrangement (). It is endeavoured to improve the control possibilities. For this purpose, it is provided that in at least one valve module () the compensation arrangement is a pre-compensation arrangement () and in at least one other valve module () the compensation arrangement is a post-compensation 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.

The invention concerns a pressure reduction valve () with a housing (), a valve element () being displaceable in the housing and acted upon in one direction by a pressure in a low-pressure chamber connected with an outlet () and in the opposite direction by the force of a spring (), which is arranged in a spring chamber () in the housing (). It is endeavoured to improve the dynamic behaviour of the pressure reduction valve. For this purpose, a pilot flow path () connects the low-pressure chamber () and the spring chamber () with each other.

Pressure reduction valve

A hydraulic valve system () has 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 motor (), with a directional valve (), which is arranged between the supply connection arrangement (P, T) and the working connection arrangement (A, B), and with a compensation valve (), which is acted upon in a first operation direction by a spring () and a pressure in a pressure chamber (), which is connected with a load-sensing line (LS), and in a second operation direction, which is opposite to the first operation direction, by a pressure at the directional valve ().

Hydraulic valve system

A hydraulic valve system ( ) has 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), which can be connected with a hydraulic motor ( ), and a directional valve ( ) between the supply connection arrangement (P, T) and the working connection arrangement (A, B), which is connected with the working connection arrangement (A, B) via working lines ( ), in which are arranged check valves ( ), which can be opened by means of pressure.

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

An add-in device for a hydraulic control arrangement provides a function unit (24) to be arranged between successive modules, which function unit takes the connection between the pump channels of the preceding and the subsequent module by way of at least one function slide valve (117, 217) which is arranged to be displaced into several positions. In its positions this function slide valve initiates different functions, by which fluid under pressure is arranged to be admitted to the subsequent control module in at least two different amounts and/or in at least two different levels of pressure. In this manner operation of the subsequent control modules can be better matched to the particular operating conditions that obtain.

Add-in device for a hydraulic control arrangement

A pressure control valve of the type having pump, tank and load-sensing connections used in conjunction with one or more proportional type valves. In this type of system a load-sensing signal is tapped off from the output side of the proportional valves and conveyed to the load-sensing connection of the pressure control valve. A pressure control valve of the type herein has load-sensing and pressure chambers at opposite ends thereof with a slide valve therebetween which is spring biased towards the pressure chamber and controls the internal flow from the pump connection to the tank connection. The slide valve has an auxiliary change-over type valve which selectively connects the pressure chamber to the pump and load-sensing connections in response to a pressure differential between the pump and load-sensing connections to achieve a pressure balance between the load-sensing chamber and the pressure chamber.

Pressure control valve

A hydraulic circuit for a backhoe loader having two double-acting cylinders for the arm and bucket of the loader and respective directional valves for the cylinders. There are heavy demands on the oil pump of the system when the two cylinders are moved simultaneously from one extreme position to another which requires substantially two whole cylinder volumes of oil. The cylinders are arranged in parallel relative to the pump. A first source of pressure medium displaced from one cylinder is used to perform work in the other cylinder and the other cylinder is also supplied with a second source of pressure medium directly from a pump. The line section through which the first source of pressure medium is supplied is shunted to a tank by valving apparatus upon a predetermined pressure being reached to freely accommodate the simultaneous movements of the cylinders.

Hydraulic circuit

The handwheel of a vehicle is connected to a handwheel shaft which in turn is connected through a load torque isolating device (overrunning clutch) that acts in either of the two directions of rotation and is connected to a steering shaft that controls a hydraulic arrangement. The hydraulic arrangement controls a steering motor that in turn controls the direction of turning of the vehicle. A second motor is drivingly connected to the overrunning clutch to rotate the steering shaft when the second motor is operated but when the steering is controlled by the handwheel, movement of the second motor is prevented. The second motor is operable from a location remote from the vehicle. The overrunning clutch includes a hub connected to the steering shaft and is movable by the handwheel shaft, the hub being wedgable against the clutch housing for being driven by the second motor by two jamming rollers that each acts in one direction of rotation and can be released by rotating the handwheel shaft. In one embodiment, the load torque isolating device may be arranged between a planetary gear and the steering handwheel shaft arrangement. Sensors and a control circuit may be arranged to achieved a direct correlation between the position of the steering handwheel and the steering angle.

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Soenderborg, Denmark

Thorkild Christensen