| 摘要 |
A hydraulic valve lash adjuster for a valve train of an internal combustion engine, for example for an automotive vehicle, said hydraulic valve lash adjuster comprising a piston ( 2 ) that is guided for displacement in a piston housing ( 4 ) and elastically supported against said housing, said piston ( 2 ) comprising a low pressure chamber ( 3 ) that communicates via an axial opening ( 26 ) in a piston bottom ( 19 ) with a high pressure chamber ( 5 ) defined by the piston housing ( 4 ) and the piston ( 2 ), and further comprising a control valve ( 6 ) acting between said pressure chambers ( 3, 5 ), said control valve ( 6 ) comprising a valve closing body ( 7 ) that can be brought to bear sealingly against a valve seat ( 24 ) that surrounds the axial opening ( 26 ) on a piston body undersurface ( 28 ) and is received in a closing body cap ( 9 ) whose cap bottom ( 21 ) acts as a stroke limitation of the valve closing body ( 7 ), and said control valve ( 6 ) further comprising a control valve spring ( 8 ) that loads the valve closing body ( 7 ) in opening direction, and, during a collapsing movement between the piston ( 2 ) and the piston housing ( 4 ), said valve closing body ( 7 ) being hydraulically loadable in closing direction against the biasing force of the control valve spring ( 8 ) by a pressure build-up in the high pressure chamber ( 5 ). To improve the valve lash adjuster so that undesired operational fluctuations are reduced, the valve closing body ( 7 ) is configured as a needle-shaped, elongate sealing piston whose valve seat-proximate end comprises a plate-shaped sealing surface ( 10 ) that cooperates with a correspondingly configured sealing surface ( 25 ) of the valve seat ( 24 ) and whose valve seat-distal end comprises a surface of application ( 12 ) for hydraulic loading, and the valve closing body ( 7 ) substantially fills a space volume of the closing body cap ( 9 ) surrounding the valve closing body ( 7 ).
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