Valve Drive Assembly for an Internal Combustion Engine

Abstract

The invention relates to a valve drive assembly for an internal combustion engine. The aim of the invention is to improve the assembly in such a manner that a stationary cam can be reliably connected to a cam that is rotatably mounted on the camshaft and to avoid malfunctions. For this purpose, a groove-type guide is arranged in the area of the base circle of the cam which is rotatably mounted on the camshaft. A pilot locking plunger is mounted in a blind bore of the base circle of the cam that is connected to the camshaft so as to rotate with it. The plunger can be displaced in a controlled manner and can be engaged with the guide disengaged therefrom. The groove-type guide in which the pilot locking plunger engages extends in the base circle of the rotatably mounted cam by approximately 180°.

1 : Valve drive assembly for an internal combustion engine, with at least two cams disposed on a camshaft and provided with different profiles, which cams selectively actuate at least one gas-exchange valve, and wherein one cam is connected to the camshaft so as to rotate with it, and the other cam is mounted rotatably on the camshaft and can be connected, by means of shape fit, to the cam disposed on the camshaft so as to rotate with it, by way of a controllable locking plunger,
 wherein   a groove-like guide ( 8 ) is disposed in the region of the base circle ( 15 ) of the cam ( 3 ) mounted rotatably on the camshaft ( 1 ), with which guide a pilot locking plunger ( 16 ), which is mounted so as to be controllably displaced in a blind-hole bore ( 17 ) of the base circle ( 14 ) of the cam ( 2 ) connected to the camshaft ( 1 ) so as to rotate with it, can be engaged and from which guide it can be disengaged.   
   
   
       2 : Valve drive assembly according to  claim 1 ,
 wherein   the groove-like guide ( 8 ) extends over approximately 180° in the region of the base circle ( 15 ) of the cam ( 3 ).   
   
   
       3 : Valve drive assembly according to  claim 1 ,
 wherein   the blind-hole bore ( 17 ) is in communication with a controllable pressurized-oil supply for displacement of the pilot locking plunger ( 16 ) in the direction of the groove-like guide ( 8 ).   
   
   
       4 : Valve drive assembly according to  claim 1 ,
 wherein   a spring ( 18 ) is disposed on the bottom of the pilot locking plunger ( 16 ), which spring acts against the oil pressure acting to displace the pilot locking plunger ( 16 ) in the direction of the groove-like guide ( 8 ), and displaces the pilot locking plunger ( 16 ) in the direction of the bottom of the blind-hole bore ( 17 ) upon disconnection of the oil pressure for displacing the pilot locking plunger ( 16 ) in the direction of the groove-like guide ( 8 ), and the connection of the cam ( 3 ) with the cam ( 2 ) is de-interlocked by means of the pilot locking plunger ( 16 ).   
   
   
       5 : Valve drive assembly according to  claim 1 ,
 wherein   a blind-hole bore ( 20 ) is disposed in the region of the cam ( 2 ), in which bore a displaceable main locking plunger ( 6 ) is controllably mounted, which plunger can be engaged with and disengaged from a blind-hole bore ( 13 ) disposed in the region of the cam ( 3 ).   
   
   
       6 : Valve drive assembly according to  claim 1 ,
 wherein   the blind-hole bore ( 20 ) in the cam ( 2 ) and the blind-hole bore ( 13 ) in the cam ( 3 ) are in communication with a controllable pressurized-oil supply for displacement of the main locking plunger ( 6 ).   
   
   
       7 : Valve drive assembly according to  claim 1 ,
 wherein   a spring ( 7 ) is disposed between the bottom of the main locking plunger ( 6 ) and the bottom of the blind-hole bore ( 20 ) in the cam ( 2 ).   
   
   
       8 : Valve drive assembly according to  claim 1 ,
 wherein   a sealing plunger ( 19 ) is disposed in the blind-hole bore ( 13 ).