Variable valve lift apparatus

Abstract

A variable valve lift apparatus include a cam rotating together with a camshaft, a lever body being rolling-contacted to one end portion of the cam, and making a lever motion by receiving torque of the cam, two valves operating depending on a lever motion of the lever body, a valve gap control device being disposed at the other end portion of the lever body to simultaneously push the two valves by a main lift and controlling a gap of the valve, and an operation portion operated to selectively push a variable valve which is one among the two valves by a sub lift and disposed at the other end portion of the lever body.

What is claimed is: 
     
         1 . A variable valve lift apparatus comprising:
 a cam rotating together with a camshaft;   a lever body being rolling-contacted to a first end portion of the cam, and making a lever motion by receiving torque of the cam;   two valves operating depending on the lever motion of the lever body;   a valve gap control device being disposed at a second end portion of the lever body to simultaneously push the two valves by a main lift and controlling a gap of the valves; and   an operation portion operated to selectively push a variable valve which is one among the two valves by a sub lift and disposed at the second end portion of the lever body.   
     
     
         2 . The variable valve lift apparatus of  claim 1 , wherein a roller is disposed at a portion that the lever body is in contact with the cam. 
     
     
         3 . The variable valve lift apparatus of  claim 1 , wherein the operation portion includes:
 an actuator operated by hydraulic pressure;   a chamber which is a volume selectively forming high pressure depending on an operation of the actuator;   a plunger making a reciprocal rectilinear motion according to pressure change in an internal of the chamber; and   a solenoid valve operated to selectively supply the hydraulic pressure to the actuator.   
     
     
         4 . The variable valve lift apparatus of  claim 3 , wherein the plunger selectively pushes the variable valve by the sub lift, and a plunger elastic portion is disposed at a lower end portion of the plunger. 
     
     
         5 . The variable valve lift apparatus of  claim 1 , wherein the sub lift of the variable valve is a lift which is lower than the main lift. 
     
     
         6 . The variable valve lift apparatus of  claim 1 , wherein a gap elastic portion is disposed at a lower end portion of the valve gap control device which simultaneously pushes the two valves. 
     
     
         7 . The variable valve lift apparatus of  claim 6 , further including:
 a valve bridge connecting the two valves,   wherein the lower end portion of the valve gap control device is configured to push the valve bridge.   
     
     
         8 . The variable valve lift apparatus of  claim 7 , wherein the variable valve is disposed to be movable up and down on the valve bridge. 
     
     
         9 . The variable valve lift apparatus of  claim 8 , further including a tappet disposed at an upper end portion of the variable valve on the valve bridge to realize a relative up and down motion of the variable valve. 
     
     
         10 . The variable valve lift apparatus of  claim 3 , wherein the cam includes:
 a base formed in an arc shape having uniform radius and a circle center which is a rotation center of the cam;   a sub lobe pushing the lever body from when opening of the variable valve is started to when closing of the variable valve is ended while the variable valve is operated by the sub lift; and   a main lobe pushing the lever body from when opening of the two valve is started to when closing of the two valve is ended by the main lift.   
     
     
         11 . The variable valve lift apparatus of  claim 10 , wherein an external diameter of the sub lobe is larger than an external diameter of the base and an external diameter of the main lobe is larger than an external diameter of the sub lobe. 
     
     
         12 . The variable valve lift apparatus of  claim 10 , wherein the base and the main lobe are formed at opposite sides to each other with respect to a rotation center of the cam, and the sub lobe is formed between the base and the main lobe. 
     
     
         13 . The variable valve lift apparatus of  claim 12 , wherein the sub lobes are formed at a first side and a second side with respect to a rotation center of the cam. 
     
     
         14 . The variable valve lift apparatus of  claim 10 , wherein when the operating portion is not operated, the variable valve is not pushed by the operating portion even while the sub lobe of the cam is in contact with the lever body. 
     
     
         15 . The variable valve lift apparatus of  claim 10 , wherein when the solenoid valve is to be ON wherein hydraulic pressure is supplied to the chamber by an operation of the actuator while the sub lobe of the cam is in contact with the lever body, the plunger is configured to be moved downwardly, pushing the variable valve. 
     
     
         16 . The variable valve lift apparatus of  claim 10 , wherein when the main lobe of the cam is in contact with the lever body, the plunger returns to an original position thereof as the solenoid valve is to be OFF wherein hydraulic pressure is released from the chamber by stop of operating the actuator. 
     
     
         17 . The variable valve lift apparatus of  claim 1 , wherein the variable valve is configured to be operated by the sub lift during an intake stroke of an engine, realizing internal exhaust gas recirculation. 
     
     
         18 . The variable valve lift apparatus of  claim 1 , wherein the variable valve is configured to be operated by the sub lift during a compression stroke of an engine, realizing engine brake. 
     
     
         19 . The variable valve lift apparatus of  claim 18 , wherein a time of opening an exhaust opening by the variable valve is a top dead center.