Electromagnetic actuator
An electromagnetic actuator including: a mover; a stator; at least one coil provided to the stator and arranged on an outer periphery of the mover, the coil being configured to be energized to generate an electromagnetic force that exerts a driving force on the mover; at least one yoke member surrounding the coil, the yoke member being constituted by a plurality of yoke segments; and a mold resin filling a space between the yoke segments and the coil, the mold resin fixing the yoke segments to each other. The mold resin extends to an outer peripheral surface of the yoke member and forms an outside resin layer.
1. An electromagnetic actuator comprising:
a mover;
a stator;
at least one coil provided to the stator and arranged on an outer periphery of the mover, the coil being configured to be energized to generate an electromagnetic force that exerts an axial driving force on the mover;
at least one yoke member surrounding the coil, the yoke member being constituted by a plurality of yoke segments arranged so as to oppose each other in an axial direction of the coil with the coil interposed therebetween; and
a mold resin filling a space between the yoke segments and the coil, the mold resin fixing the yoke segments to each other, wherein:
the mold resin extends to an outer peripheral surface of the yoke member and forms an outside resin layer,
at least one of the yoke segments includes an annular part protruding radially inward from a vertical outer end thereof, the coil includes a resin bobbin around which a coil wire is wound, and the mold resin fills a respective space between the annular part and the resin bobbin,
an entire surface of the resin bobbin, which is on a side opposing the annular part in the axial direction of the coil, is held in contact via the mold resin with the annular part, and
the plurality of yoke segments arranged so as to oppose each other in the axial direction of the coil, are opposed to each other in the axial direction via the mold resin without having abutting contact with another yoke segment in the axial direction in a part of an outer peripheral side of the coil in a circumferential direction.
2. The electromagnetic actuator according to claim 1 , wherein the outside resin layer covers an entirety of the outer peripheral surface of the yoke member.
3. The electromagnetic actuator according to claim 1 , wherein the mover comprises a mass member, and the stator includes an attachment to a target member whose vibration is to be damped such that the electromagnetic actuator constitutes an active vibration damper with respect to the target member.
4. The electromagnetic actuator according to claim 1 , wherein
the at least one coil of the stator comprises a first coil and a second coil overlapped with each other in an axial direction,
the at least one yoke member comprises a first yoke member which is constituted by a plurality of yoke segments while surrounding the first coil, and a second yoke member which is constituted by a plurality of yoke segments while surrounding the second coil, and
the plurality of yoke segments of the first yoke member and the plurality of yoke segments of the second yoke member are fixed to one another by the mold resin.
5. The electromagnetic actuator according to claim 1 , wherein the yoke member includes a tube part located on an outer periphery of the coil, the tube part having a through hole, and the mold resin fills a radial inside of the tube part via the through hole.
6. The electromagnetic actuator according to claim 1 , wherein the coil includes a power feed terminal that is conductive with respect to the coil wire, and a connector for external connection in which the power feed terminal is arranged is integrally formed by the mold resin.
7. The electromagnetic actuator according to claim 1 , wherein the mold resin molded in a presence of the resin bobbin is fixed to the resin bobbin.
8. The electromagnetic actuator according to claim 1 , wherein the entire surface of the resin bobbin, which is on the side opposing the annular part, is entirely covered by the annular part with the mold resin interposed in-between.
9. The electromagnetic actuator according to claim 1 , wherein
a yoke segment of the plurality of yoke segments is arranged to oppose the annular part in the axial direction of the coil with the coil interposed therebetween, and is integrally formed with the resin bobbin.
10. The electromagnetic actuator according to claim 1 , wherein
an entire inner surface of a yoke segment of the plurality of yoke segments, which is arranged to oppose the annular part in the axial direction of the coil with the coil interposed therebetween, directly contacts the resin bobbin.