Valve drive

Abstract

Valve drive with a first actuator ( 1 ) for opening and/or closing a gas-exchange valve ( 2 ), in particular of an internal combustion engine, and a separate second actuator ( 3 ) for the valve-play compensation of the gas-exchange valve ( 2 ), the second actuator ( 3 ) being developed as a double-action, preferably hydraulic, piston cylinder arrangement with at least two working surfaces (A 1 , A 2 ) that can be subjected to pressure.

1 . Valve drive with a first actuator for opening or closing a gas-exchange valve and a separate second actuator for the valve-play compensation of the gas-exchange valve, wherein the second actuator is developed as a double-action piston cylinder arrangement with at least two working surfaces that can be subjected to pressure.  
   
   
       2 . Valve drive according to  claim 1 , wherein the double-action piston cylinder arrangement has at least two equal-sized working surfaces and the second actuator has an additional elastic element.  
   
   
       3 . Valve drive according to  claim 1 , wherein the additional elastic element is a helical spring.  
   
   
       4 . Valve drive according to  claim 1 , wherein the double-action piston cylinder arrangement is developed as a differential piston cylinder arrangement with at least two different-sized working surfaces.  
   
   
       5 . Valve drive according to  claim 1 , wherein the first actuator is essentially located in the piston of the piston cylinder arrangement of the second actuator.  
   
   
       6 . Valve drive according to  claim 5 , wherein the first actuator can be actuated hydraulically or pneumatically or electrically.  
   
   
       7 . Valve drive according to  claim 1 , wherein the first actuator has a bush, the piston cylinder arrangement of the second actuator being essentially arranged in the bush.  
   
   
       8 . Valve drive according to  claim 7 , wherein the bush is a bush-shaped piston.  
   
   
       9 . Valve drive according to  claim 7 , wherein the first actuator can be actuated hydraulically or pneumatically or electrically or by means of a cam or a camshaft.  
   
   
       10 . Valve drive according to  claim 1 , wherein the working surfaces each at least partially border a compensation chamber, and an inlet throttle is arranged in each case between each compensation chamber and a feed line for pressurized fluid.  
   
   
       11 . Valve drive according to  claim 10 , wherein the feed line is located essentially centrally between the inlet throttles.  
   
   
       12 . Valve drive according to  claim 10 , wherein a pressure of at least 100 bar can he applied at the feed line.  
   
   
       13 . Valve drive according to  claim 10 , wherein a pressure of at least 200 bar can be applied at the feed line.  
   
   
       14 . Valve drive according to  claim 10 , wherein the inlet throttles have different throttle coefficients.  
   
   
       15 . Valve drive according to  claim 10 , wherein an outlet throttle is located in each case between each compensation chamber and at least one drain line for draining off the fluid.  
   
   
       16 . Valve drive according to  claim 15 , wherein the throttle coefficient of the outlet throttles is greater than the throttle coefficient of the inlet throttles.  
   
   
       17 . Valve drive according to  claim 10 , wherein the fluid is a hydraulic fluid or a gas.  
   
   
       18 . Valve drive according to  claim 1 , wherein the first actuator opens or closes a gas-exchange valve of an internal combustion engine.  
   
   
       19 . Valve drive according to  claim 1 , wherein the second actuator is developed as a double action hydraulic piston cylinder arrangement.