Switchable lever for a valve drive of an internal combustion engine

Abstract

A switchable lever for a valve drive of an internal combustion engine which has two side walls with ends connected by a crossbar. There is a gas-exchange valve system in the crossbar at one end and a bearing for the pivotable support of the crossbar at the other end. An axle is held nondisplaceably in the side walls, between the ends, with two cam rollers running on the axle. The cam rollers are displaceable axially on the axle toward each other into a first position such that the cam rollers run up to each other on a longitudinal center plane of the lever and away from each other into a second position. One of the positions serves for a high-lift cam contact and the other position serves for a low-lift or zero-lift cam contact.

1 - 11 . (canceled) 
     
     
         12 . A switchable lever for a valve drive of an internal combustion engine, comprising:
 an elongated housing having two side walls, one end of the housing having a crossbar for a gas-exchange valve system and another end of the housing for a bearing;   an axle transverse to and fixed in the housing;   two cam rollers rotatable on and concentric with the axle, the rollers transversely displaceable on the axle between a first position where the rollers abut each other and a second position where the rollers are spaced transversely apart from each other;   a first means for positioning the rollers in the first position, the first means in the housing between the housing and rollers; and   a second means for positioning the rollers in the second position, the second means in the housing between the rollers.   
     
     
         13 . The lever according to  claim 12 , wherein the first position provides a low-lift cam contact and the second position provides a high-lift cam contact. 
     
     
         14 . The lever according to  claim 12 , wherein each of the cam rollers have an annular casing and outer faces with pockets that have bores formed in the outer faces. 
     
     
         15 . The lever according to  claim 14 , further comprising a pair of diametrically opposite support rollers arranged on the axle, adjacent to the side walls, the support roller have an outside diameter that is smaller than an outside diameter of the cam rollers and an outer casing on which the cam rollers are at least partially mounted and an inner face opposing the cylindrical pockets of the cam rollers. 
     
     
         16 . The lever according to  claim 15 , wherein the first means is a pressure space for hydraulic medium that can be introduced via the axle, the pressure space is formed axially between the bases of the cylindrical pockets and the inner face of the support roller, which is adjacent to the cylindrical pockets. 
     
     
         17 . The lever according to  claim 14 , wherein the second means is a mechanical spring means that is clamped between the inner faces of the cam rollers. 
     
     
         18 . The lever according to  claim 17 , wherein the cam rollers can be displaced towards each other to achieve the first position, which is counter to a force of the spring means, by a high pressure of the hydraulic medium, which can be conducted into the pressure space. 
     
     
         19 . The lever according to  claim 17 , wherein the cam rollers can be displaced away from each other by a force of the spring means to achieve the second position when a high pressure at the hydraulic medium switched off. 
     
     
         20 . The lever according to  claim 17 , wherein the spring means comprises at least one helical compression spring. 
     
     
         21 . The lever according to  claim 17 , wherein the cam rollers have an inner face with opposing annular pockets, which run in a radial region above the support rollers and the opposing annular pockets have bottoms and the end sides of the spring means are supported on the bottoms of the pockets. 
     
     
         22 . The lever according to  claim 15 , further comprising an axial passage in the axle, which has at least one radial passage that branches off from the axial channel at least partially in the pressure space and is positioned axially in a region of the inner face of the support rollers. 
     
     
         23 . The lever according to  claim 22 , further comprising a supply line for the hydraulic medium having a transverse channel in the crossbar, a longitudinal channel in one of the side walls and an annular-groove/bore overflow in the axle, the supply line extends outwardly from the bearing at the second end via the transverse channel, the transverse channel opens at an outer end into the longitudinal channel, the longitudinal channel communicates with the annular-groove/bore overflow and from the annular-groove/bore overflow the supply line is conducted further to the axial channel in the axle. 
     
     
         24 . The lever according to  claim 14 , further comprising a stop element running centrally on the axle with the inner faces of cam rollers hearing against the stop element when the earn rollers are displaced into the first position. 
     
     
         25 . The lever according to  claim 24 , wherein the stop element is a snap ring. 
     
     
         26 . The lever according to  claim 15 , wherein at least one of the support rollers is slideable on the axle. 
     
     
         27 . The lever according to  claim 12 , wherein the sidewalls have an expanded center section, the center section is adjoined at each end by intermediate sections with inwardly angled contours, and the intermediate sections are adjoined by approximately rectilinear end sections. 
     
     
         28 . The lever according to  claim 12 , wherein the lever has a U-shaped pro file or upside down U-shaped profile in cross-section. 
     
     
         29 . The lever according to  claim 12 , wherein the side walls and crossbars are composed of a steel sheet or are produced by metal injection molding. 
     
     
         30 . The lever according to  claim 12 , wherein the lever is a rocker arm lever which has a dome at the second end of the bearing. 
     
     
         31 . The lever according to  claim 12 , wherein the lever is an oscillating lever which has an eye at the second end for the pivotable mounting on the axle. 
     
     
         32 . The lever according to  claim 12 , wherein the cam rollers are interchangeable or are at least substantially identical with regard to geometry and dimensioning.