Electromagnetic actuator

Abstract

An electromagnetic actuator includes a pair of core assemblies and a spacer. An armature is provided between the pair of core assemblies. The spacer is molded to be integral with a coil provided in electromagnets of the core assemblies. The spacer is located between the electromagnets. A relative position of the pair of electromagnets with respect to each other can be determined by the size of the spacer. A space that allows the armature to reciprocate is securely defined by the spacer located between the core assemblies.

What is claimed is:  
     
         1 . An electromagnetic actuator comprising: 
 an armature that reciprocates along an axis;    a pair of electromagnets, each having a coil, the pair of electromagnets provided along the axis and on opposite sides of the armature; and    a spacer formed by molding to be integral with the coil and located between the pair of electromagnets, the spacer secures a space for the armature to reciprocate along the axis.    
     
     
         2 . The electromagnetic actuator according to  claim 1 , wherein the electromagnetic actuator has at least two of the spacers.  
     
     
         3 . The electromagnetic actuator according to  claim 2 , wherein the spacers are located on opposite sides of the armature as viewed in a direction perpendicular to the axis.  
     
     
         4 . The electromagnetic actuator according  claim 1 , wherein a noise absorbing material is provided between a first surface defined by at least one of the spacer and the coil opposite to a side adjacent to the armature and a second surface defined matingly opposite to the first surface.  
     
     
         5 . The electromagnetic actuator according  claim 4 , wherein the noise absorbing material is provided at least one of the spacer and the coil.  
     
     
         6 . The electromagnetic actuator according to  claim 4 , wherein the noise absorbing material comprises a foam metal.  
     
     
         7 . The electromagnetic actuator according to  claim 1 , wherein a surface of the armature is hardened by a surface-hardening treatment.  
     
     
         8 . The electromagnetic actuator according  claim 1 , wherein the electromagnetic actuator is provided in an internal combustion engine to drive a valve body of an intake valve.  
     
     
         9 . The electromagnetic actuator according  claim 1 , wherein the electromagnetic actuator is provided in an internal combustion engine to drive a valve body of an exhaust valve.