Empa Eidgenossische Materialprufungs-und Forschungsanstalt

Wolfgang Schneider Ingenieurburo

Bieri Hydraulik Ag

Hydac Engineering Ag

Wolfgang Schneider

Patrik Soltic

Andyn Omanovic

Maxim Reichert

Ulrich Josi

In order to provide a more reliable configuration for a hydraulic drive for accelerating and braking in particular a gas exchange valve () of internal combustion engines or other reciprocating engines, in particular if the occurring maximum travel of the moving mass can deviate considerably from an expected setpoint position, it is proposed that the drive piston () has at least one control edge () corresponding to an inflow opening (), which, when a defined travel hhas been attained, prevents the inflow of drive pressure pinto the drive chamber () and/or prevents the low-loss outflow of pressure medium from the brake chamber () to the basic pressure level (), wherein the remaining hydraulic drive force vanishes, becomes small or changes its sign when said travel his attained.

Hydraulic drive for accelerating and braking components

In order to ensure a simple, reliable and recuperative operation in a hydraulic drive () for accelerating and braking a gas exchange valve () of internal combustion engines or other reciprocating engines, it is proposed that a first pressure reservoir () for providing a first pressure pcomprises a restoring energy accumulator, preferably configured as a spring (), and at least one hydraulic base pressure reservoir (), which has a lower pressure pthan the first pressure reservoir (). In a connecting line () between the first hydraulic pressure reservoir () and the working cylinder (), a controllable opening () of a first valve () comprising at least one check valve () is arranged upstream or downstream in the flow path, which allows the pressure medium () to flow in the direction of working cylinder (), but prevents a backflow towards the pressure reservoir (). In order to also initiate the closing movement or to enable the breaking of the gas exchange valve in a hydraulically simple and reliable manner, in a second connecting line () between the first pressure reservoir () and the working cylinder () there is arranged a controllable opening () of a second valve () comprising a check valve (), which prevents a flow in the direction of the working cylinder (), but allows a return flow in the direction of the pressure reservoir ().

Hydraulic drive for accelerating and braking dynamically moving components

A valve device () includes a tank pressure port (), a first pressure port (), a second pressure port (), and a pressure shut-off valve (). The valve is switched between the individual ports (), and has two valve components (). Upon reaching a predefinable pressure cut-off value, the first pressure port () can be connected to the tank pressure port () by the first valve component (). In the event of the fluid pressure being higher at the second pressure port () than at the first pressure port (), the second pressure port () can be separated from the first pressure port () by the second valve component (). Both valve components () are combined to form a tradable structural unit and are integrated in a common valve housing (), preferably making direct contact. A hydraulic system has this valve device.

Valve device and hydraulic system

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Thun, Switzerland

Wolfgang Schneider