Patent ID: 7146954

Claim:
A reverse spring hydraulic valve-lash-adjusting element for the valve train of an internal combustion engine, which is characterized by the following features: a housing of a valve-lash-adjusting element has a blind bore in which a plunger ( 1 ) is guided with sealing clearance; the plunger ( 1 ) has a plunger head, ( 2 ), which together with the blind bore defines a high-pressure space ( 3 ), whereas a low-pressure space ( 4 ) is located above the plunger head ( 2 ); the pressure spaces ( 3 , 4 ) are connected by a central axial opening ( 6 ) in the plunger head ( 2 ), this axial opening ( 6 ) being controlled by a control valve ( 5 ) arranged on the underside of the plunger head ( 2 ); the control valve ( 5 ) has a valve-closing body ( 7 ) which has a hemispherical sealing surface, which together with a cylinder-ring-shaped sealing surface ( 8 ) arranged on the plunger head ( 2 ) forms a circular sealing line; a valve-body spring ( 17 ), which is supported on a step ( 19 ) between the central axial bore ( 6 ) and the sealing surface ( 8 ) located blow the latter, loads the valve-closing body ( 7 ) in the opening direction, whereas a positive pressure in the high-pressure space ( 3 ) loads the valve-closing body ( 7 ) in the closing direction; a closing-body cap ( 10 ) has a cap flange ( 11 ), an essentially cylindrical cap centre piece ( 12 ) and a cap base ( 13 ) provided with openings ( 21 ); the closing-body cap ( 10 ) is supported and centered on the plunger head ( 2 ), and the cap base ( 13 ) serves as a travel limit for the valve-closing body ( 7 ); pressure is applied to the plunger ( 1 ) via the cap flange ( 11 ) by a compression spring ( 23 ) arranged in the high-pressure space ( 3 ), characterized in that a cylindrical and axially parallel guide surface ( 20 , 20 a ) connected to a plunger head ( 2 , 2 a ) is provided, this guide surface ( 20 , 2 O aq ) enclosing a corresponding guide line ( 40 ) or guide surface ( 25 , 29 , 30 ) of a valve-closing body ( 7 , 7 a , 7 b , 7 c , 7 d , 7 e , 7 f , 7 g ) with guide clearances the valve-body springs ( 17 , 17 a ) are cylindrical or conical compression springs and the cylindrical guide surface ( 20 , 20 a ) connected to the plunger head ( 2 ) is the inside of the cylindrical cap center piece ( 12 , 12 a , 12 b ) of the closing-body cap ( 10 , 10 a , 10 b , 10 c , 10 d , 10 e , 10 f , 10 g ) wherein the underside ( 16 ) of the plunger head ( 2 ) has a concentric bore ( 15 ) which extends up to the cylinder-ring-shaped sealing surface ( 8 ) and has a shoulder ( 14 ), on which the cap flange ( 11 ), which is centered in the bore ( 15 ), rests, the valve-closing body ( 7 , 7 a ) of a control valve ( 5 , 5 a ) is designed as a ball (a “needle”) extended by a circular-cylindrical intermediate piece ( 25 ), and in that the cap base ( 13 ) has a centerr piece ( 24 ) serving as travel limit and having openings arranged in a rotationally symmetrical manner around the said center piece ( 24 ) designed as holes ( 21 ).