Hydraulic bucket tappet

Abstract

A hydraulic tappet for internal combustion engines with overhead camshaft has hollow cylindrical housing that is sealed at one end by a tappet floor that is mechanically linked to a cam of a camshaft. Longitudinally borne in the housing is a hydraulic play compensation unit, the pressure chamber of which, for exchanging fluid, can be connected to a fluid reservoir that is sealed to the outside. For compensating volume from the fluid reservoir, a largely circular compensation element that limits the fluid reservoir is provided and that is provided with at least one undulation and/or fold. The compensation element is arranged such that the center region is freely movable and the undulation and/or fold opens or closes depending on the required volume compensation.

1 . Hydraulic tappet for internal combustion engines with an overhead camshaft, comprising a hollow cylindrical housing that is sealed at one end by a tappet floor that is mechanically linked to a cam of the camshaft, a hydraulic play compensation unit in said housing, said hydraulic play compensation unit having a pressure chamber of which, for exchanging fluid, can be connected to a fluid reservoir that is sealed to the outside wherein for compensating the volume from said fluid reservoir, a compensation element that limits the fluid reservoir and provided with at least one undulation and/or folds is provided, whereby said compensation element being arranged such that the center region thereof is freely movable and said undulation and/or fold opens or closes depending on the required volume compensation.  
     
     
         2 . Hydraulic tappet in accordance with  claim 1 , wherein said compensation element is arranged outside of the power force between said cam and a valve lifter.  
     
     
         3 . Hydraulic tappet in accordance with  claim 1  or  2 , wherein said compensation element is embodied such that said undulation and/or fold opens and closes with almost no pressure.  
     
     
         4 . Hydraulic tappet in accordance with  claim 1  or  2  wherein said compensation element is a bellows.  
     
     
         5 . Hydraulic tappet in accordance with  claim 1  or  2 , wherein said housing has a housing floor integral with said housing at the side facing away from said tappet floor.  
     
     
         6 . Hydraulic tappet in accordance with  claim 5 , wherein said compensation element stands on said housing floor.  
     
     
         7 . Hydraulic tappet in accordance with  claim 1  or  2 , wherein said housing is sealed in the direction of said camshaft by said tappet floor and a bushing.  
     
     
         8 . Hydraulic tappet in accordance with  claim 7 , wherein said tappet floor and said bushing are displaceably arranged in said housing.  
     
     
         9 . Hydraulic tappet in accordance with  claim 7 , comprising a spring is arranged between said bushing and said housing floor.  
     
     
         10 . Hydraulic tappet in accordance with  claim 7 , wherein a seal is arranged between said bushing and said housing.  
     
     
         11 . Hydraulic tappet in accordance with  claim 7 , wherein said bellows is clamped between said bushing and said tappet floor.  
     
     
         12 . Hydraulic tappet in accordance with  claim 11 , wherein said bellows has on its exterior circumference an O-ring-shaped form that can be pressed in or compressed between said bushing and said tappet floor.  
     
     
         13 . Hydraulic tappet in accordance with  claim 7 , wherein said bellows is vulcanized at said bushing and/or at said tappet floor.  
     
     
         14 . Hydraulic tappet in accordance with  claim 1  or  2 , wherein said tappet floor has a free space for receiving said opened undulation and/or fold.  
     
     
         15 . Hydraulic tappet in accordance with  claim 14 , wherein said free space is maintained with no pressure by an opening in said tappet floor.  
     
     
         16 . Hydraulic tappet in accordance with  claim 10 , wherein said seal is an o-ring.