Patent ID: 6427649
Filing Date: 2002-08-06
Classification: F01L

Abstract:
Electromagnetic actuator (1) for controlling valves (2) of an internal-combustion engine comprising a head (4), at least one combustion chamber (5) having a variable volume, at least one connection pipe (6) which puts the combustion chamber (5) in communication with an exterior, and at least one valve (2) that can regulate passage of fluids from and towards the combustion chamber (5), the valve (2) being fitted such as to be axially mobile in the head (4) between a position of closure in which the valve shuts the connection pipe (6), and a position of maximum opening in which the valve permits passage of the fluids through the connection pipe (6) with a maximum permissible flow rate; the electromagnetic actuator (1) being fitted on the head (4) in order to move the valve (2) by command between the valve position of closure and the valve position of maximum opening, the actuator comprising:means for recovery of the mechanical play which exists between the valve (2) and the actuator (1); a frame (10) pivoted on the head (4) of the engine, such that the actuator can rotate around a first axis of rotation (B), which is substantially perpendicular relative to the axis of movement (L) of the valve (2); wherein said means for recovery of the mechanical play comprises a device for regulation of the position of the frame (24) relative to the head (4), which can rotate said frame (10) by command around said first axis of rotation (B) to keep the mechanical play at a pre-determined value; an oscillating arm (11) having a first end (11a) pivoted on said frame (10) such that the actuator can oscillate around a second axis of rotation (A), which is parallel to said first axis of rotation (B), and a second end (11 b) connected to the valve (2), and a pair of electromagnets (12), which can make said oscillating arm (11) rotate by command, in order to displace the valve (2) axially between the valve position of closure and the valve position of maximum opening; a strut (30) interposed between said second end (11b) of the oscillating arm (11) and the valve (2) of the internal-combustion engine; and a flexible coupling (31), which keeps said strut (30) integral with the valve (2) of the internal-combustion engine.