Patent ID: 7978038

Claim:
Electromagnetic actuator with variable reluctance comprising: an actuator body, a ferromagnetic armature fixed to said actuator body, called the fixed armature, comprising at least two concentric cylinders of revolution, called the inner cylinder and the outer cylinder respectively, spaced radially from one another and extending along an axis, called the actuator axis, said inner cylinder and outer cylinder being connected by a connecting ring extending in a plane orthogonal to said actuator axis, at least one magnetizing winding arranged between said inner cylinder and outer cylinder, at least one ferromagnetic movable armature arranged facing one axial end of said fixed armature, called the air-gap end, each movable armature being guided in reciprocating translation movements relative to said fixed armature along said actuator axis, with which fixed armature it defines a magnetic circuit with an air gap, the dimension of which varies during the reciprocating translation movements of this movable armature relative to the fixed armature, wherein said fixed armature comprises at least two series of slots, a first series of slots provided radially in said outer cylinder and extending over the entire height of said outer cylinder, and a second series of slots provided radially in said outer cylinder and inner cylinder and extending only over a part of the height of said cylinders from each air-gap end so that non-slotted portions of the fixed armature are remote from each air gap, each slot of said second series of slots being interposed between two slots of said first series of slots.