Finger lever of a valve train of an internal combustion engine

Abstract

The invention proposes a finger lever ( 1 ) of an internal combustion engine, said finger lever ( 1 ) being switchable to different valve lifts for at least one gas exchange valve and comprising an outer lever ( 2 ) having two arms ( 3 a , 3 b ) between which an inner lever ( 6 ) is arranged for pivoting relative to the outer lever ( 2 ), which outer and inner levers ( 2, 6 ) can be coupled to each other by a coupling element ( 15 ) so that, upon coupling, a high valve lift, and upon uncoupling, a low valve lift is generated, the finger lever ( 1 ) further comprising on one end ( 7 ), a support (( 8 ) for a gas exchange valve, on an opposite end ( 4 ), a complementary surface ( 9 ) for a support element and on at least one of the outer and inner levers ( 2, 6 ), a contact surface ( 14 ) for a cam. In the finger lever ( 1 ) of the invention, the outer lever ( 2 ) is configured to transfer a high cam lift and the inner lever ( 6 ) is configured to transfer a low cam lift, and only the inner lever ( 6 ) comprises a rotatable roller acting as said contact surface ( 14 ) while each arm ( 3 a , 3 b ) of the outer lever ( 2 ) comprises a sliding contact surface acting as a cam contacting surface. In this way, a switchable finger lever ( 1 ) is provided in which only that part of the lever comprises a roller acting as a contact surface ( 14 ) that is predominantly activated during the operation of the internal combustion engine. In the present case, this is the inner lever ( 6 ).

What is claimed is:  
     
         1 . A finger lever of a valve train of an internal combustion engine, said finger lever being switchable to different valve lifts for at least one gas exchange valve and comprising an outer lever having two arms between which an inner lever is arranged for pivoting relative to the outer lever, which outer and inner levers can be coupled to each other by a coupling element so that, upon coupling, a high valve lift, and upon uncoupling, a low valve lift is generated, the finger lever further comprising on one end, a support for a gas exchange valve, on an opposite end, a complementary surface for a support element and on at least one of the outer and inner levers, a contact surface for a cam, wherein only that one of the outer and inner levers that, empirically or statistically seen, predominantly transfers the cam lift to the gas exchange valve during operation of the internal combustion engine comprises a rotatable roller acting as a cam contact surface.  
     
     
         2 . A finger lever of a valve train of an internal combustion engine, said finger lever being switchable to different valve lifts for at least one gas exchange valve and comprising an outer lever having two arms between which an inner lever is arranged for pivoting relative to the outer lever, which outer and inner levers can be coupled to each other by a coupling element so that, upon coupling, a high valve lift, and upon uncoupling, a low valve lift is generated, the finger lever further comprising on one end, a support for a gas exchange valve, on an opposite end, a complementary surface for a support element and on at least one of the outer and inner levers, a contact surface for a cam, wherein the outer lever is configured to transfer a high cam lift and the inner lever is configured to transfer a low cam lift, and only the inner lever comprises a rotatable roller acting as a cam contacting surface while each arm of the outer lever comprises a sliding contact surface acting as a cam contacting surface.  
     
     
         3 . A finger lever of  claim 2 , wherein the inner lever comprises, on the one end, the support for the gas exchange valve and, on the opposite end, the complementary surface for the support element, a fulcrum of the outer lever being situated in a region of the complementary surface.  
     
     
         4 . A finger lever of  claim 3 , wherein the coupling element is constituted by at least one transversely extending slide whose axial line is aligned to an axial line of the roller acting as a contact surface in the inner lever.  
     
     
         5 . A finger lever of  claim 4 , wherein, in a region of the one end comprising the support, the inner lever projects clearly beyond an end of the outer lever, the roller acting as a contact surface being situated approximately in a region of a central transverse plane of the inner lever.  
     
     
         6 . A finger lever of  claim 3 , wherein the complementary surface of the inner lever is configured as a cup-shaped recess.  
     
     
         7 . A finger lever of  claim 3 , wherein, at the opposite end, ends of a cross-pin project beyond the inner lever, on which ends, the arms of the outer lever are mounted through their fulcrums formed by a bore in each of the arms.  
     
     
         8 . A finger lever of  claim 7 , wherein, in a region of the opposite end, the arms of the outer lever are connected on a cam-proximate side by a crossbar, said crossbar being surrounded at least on one side between the outer and the inner lever by at least one torsion spring acting as a lost motion spring that acts at one end against the crossbar and at another end against a stop of the inner lever.