Patent ID: 6546904
Filing Date: 2003-04-15
Classification: F01L

Abstract:
An electromagnetic actuator (1) for the actuation of valves (2) of an internal combustion engine which comprises: a head (4), at least one variable -volume combustion chamber (5), at least one connection duct (6) adapted to bring the combustion chamber (5) into communication with atmosphere, and at least one valve (2) adapted to regulate the flow of fluids to and from the combustion chamber (5), the valve (2) being mounted in the head (4) so that the valve can move axially between a closed position in which the valve closes off the connection duct (6) and a position of maximum opening in which the valve enables fluids to flow through the connection duct (8, 9) with maximum admissible flow, the electromagnetic actuator (1) being mounted on the head (4) in order to move, on command, the valve (2) between its closed position and its position of maximum opening, and being characterised in that the actuator comprises means for recovering mechanical play (24; 30) between the valve (2) and the actuator (1), and a frame (10) which is connected to the head (4) of the engine so as to be able to oscillate about a first axis of rotation (B, Bâ€²) substantially perpendicular to the axis of movement (L) of the valve (2), the means for recovering the mechanical play (24; 30) comprising a device for adjusting the position of the frame (24; 30) with respect to the head (4) which is adapted to rotate, on command, the frame (10) about the first axis of rotation (B, Bâ€²) so as to maintain the mechanical play at a predetermined value said actuator further comprising:an oscillating arm (11) which has a first end (11a) hinged on the frame (10) so as to be able to oscillate about a second axis of rotation (A) parallel to the first of axis of rotation (B) and a second end (11b) connected to the valve (2), and a pair of electromagnets (12) adapted to cause the oscillating arm (11) to rotate, on command, in order axially to displace the valve (2) between the closed position and the position of maximum opening, a first elastic member (20) adapted to maintain the valve (2) in the closed position, the second end (11a) of the oscillating arm (11) being disposed in abutment on the valve (2) so as to be able to transmit only an axial thrust contrary to that of the first elastic member (20), and a second elastic member (22) adapted to maintain the valve (2) in the position of maximum opening, by exerting on said valve (2) an axial thrust contrary to that of the first elastic member (20), wherein the second elastic member (22) is connected to a bearing member (13) of the frame (10), the device for adjusting the position of the frame (24; 30) acting on said bearing member (13).