Abstract: A multiway valve, which includes a piston slide valve and at least five control chambers, of which a middle chamber comprises an intake chamber for a pressure medium, chambers adjacent the middle chamber are connected to actuators, and chambers outside the adjacent chambers are connected to a reservoir at a preset pressure level wherein, in the area of piston guide gaps formed between the intake chamber and actuator chambers, a first annular space is provided, which in a middle position of the position slide valve, in which an intake of the pressure medium source and connections of the actuators are closed, is connected by ducts in the piston slide valve to a reduced pressure level source.

Abstract: A valve comprising a valve housing, a bore in said valve housing, annular grooves defining annular channels arranged in said valve housing and adapted to be connected to valve ports arranged in said housing, a control spool reciprocally mounted within said bore so as to connect and separate said valve ports, and land means in at least one of said annular channels so as to block the rotation of said control spool, said land means extending into said at least one channel transversely to the direction of flow of the pressure medium, said land means extending substantially radially into said annular channel.

Abstract: The present invention relates to the use of two different sealing means in a directional spool valve. On the one hand side, a pressure guide element is provided at the spool so as to make sure that the pressure medium can only flow in radial direction against a seal located in the housing. The second sealing means may be of different design. It is possible that a spool seat surface provided on the spool and moveable against the force of a spring is used, said spool seat surface being adapted to cooperate with a stationary seat surface provided at the housing; alternatively a plurality of control bores is provided in the housing in the area of a port, said bores having a relatively small diameter d, and wherein a seal located the spool is used for opening and closing said bores so that no damage of the seal can occur. It is also possible to make use of the last mentioned sealing principle by itself.

Abstract: The present invention relates to the use of two different sealing means in a directional spool valve. On the one hand side, a pressure guide element is provided at the spool so as to make sure that the pressure medium can only flow in radial direction against a seal located in the housing. The second sealing means may be of different design. It is possible that a spool seat surface provided on the spool and moveable against the force of a spring is used, said spool seat surface being adapted to cooperate with a stationary seat surface provided at the housing; alternatively a plurality of control bores is provided in the housing in the area of a port, said bores having a relatively small diameter d, and wherein a seal located the spool is used for opening and closing said bores so that no damage of the seal can occur. It is also possible to make use of the last mentioned sealing principle by itself.

Abstract: A three chambered solenoid-actuated directional control valve in which a spool is reciprocally mounted for movement within a valve housing. The housing and spool define the three chambers with one adapted to be connected to a pump for supplying hydraulic fluid, the second adapted for connection to a first load and the third adapted to connection to a second load. A solenoid is reciprocally mounted for movement along the direction of the bore for actuating the spool with a rod fixedly mounted to the armature of the solenoid. At least one groove is formed between the outer surface of the armature and the inner bore of the valve housing for conducting flow of hydraulic fluid between a recess at the end of the solenoid adjacent the three chambers and the end remote therefrom. A throttle in the form of a single cross wall having either a groove or bore extending therethrough dampens movement of the armature to reduce pressure peaks during switching. Throttle grooves are also provided on the lands of the spool.