Schaeffler Technologies Ag & Co .kg

Jens Lang

Mario Kuhl

Joachim Seitz

Calin Petru Itoafa

Lothar Von Schimonsky

Thomas Kremer

Joachim Krause

Andreas Eichenberg

A hydraulic unit () is provided for a cylinder head () of an internal combustion engine with a hydraulically variable valve train (). In the hydraulic unit, a high-pressure chamber (), a medium-pressure chamber (), and a low-pressure chamber () used as the hydraulic medium reservoir are formed. The low-pressure chamber communicates via a throttle point ('&#x2033;) with the medium-pressure chamber, and the throttle point is formed by a displaceable valve body (&#x2032;&#x2033;) and has through-flow cross sections of different sizes according to a position of the valve body.

Hydraulic unit for a cylinder head of an internal combustion engine with hydraulically variable gas-exchange valve train

A coupling device () of a switchable cam follower (), in which a borehole () extends above a contact () for a support element in an outer lever () of the cam follower (), and this borehole has a first section () of large diameter that starts from an outer side () of a crosspiece () on the other end () to which connects to a second section () of accordingly smaller diameter up to directly before an inner side () of the crosspiece (). A smooth cylindrical coupling slide () is guided in a sealing manner through the second section (), and this coupling slide projects with a sub-region () into the first section (). This sub-region () is encompassed by a compression spring () that acts, on one end, against an annular end () formed between the sections () and, on the other end, against a catch element () arranged on the lateral surface () of the sub-region (). The first section () is closed by a thin-walled plug (), such that a pressure space () for hydraulic medium is located axially between the annular end () of the borehole () and an inner side () of the plug (), and for a coupled case, the coupling slide () can be brought into contact by hydraulic medium that can be guided into the pressure space () before its outer end () with a sub-region () extending on its inner end () with a catch surface () of a cross region () of the inner lever () and, for a decoupled case, the coupling slide () can be displaced in the direction toward the plug () such that it is out of contact from the catch surface () for a switched-off/reduced hydraulic medium pressure via the compression spring ().

Coupling device of a switchable cam follower of a valve train of an internal combustion engine

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Pressig, Germany

Jens Lang