Electromagnetic actuator
An electromagnetic actuator includes a mover, a stator, a bobbin module, and a first annular seal member. The bobbin module includes: a through hole, through which the stator passes along an axis line; a bobbin side receiving part, adjacent to an outer side of one end opening of the through hole and receiving the first annular seal member; and a protrusion, protruding from an inner wall surface near the one end opening. The stator includes: an outer peripheral fitting part, fitted into the protrusion; and a stator side receiving part, receiving the first annular seal member in cooperation with the bobbin side receiving part. The bobbin module and the stator define a communication path that communicates from an internal space of the through hole deviated from the protrusion to the first annular seal member in an assembled state in which the outer peripheral fitting part is fitted into the protrusion.
1 . An electromagnetic actuator comprising:
a mover, reciprocating along a predetermined axis line;
a stator, accommodating the mover to be capable of reciprocating in a direction of the axis line;
a bobbin module, arranged around the stator; and
a first annular seal member, interposed between the bobbin module and the stator, wherein
the bobbin module comprises: a through hole, through which the stator passes in the direction of the axis line; a bobbin side receiving part, formed adjacent to an outer side of one end opening of the through hole and receiving the first annular seal member; and a protrusion, formed protruding from an inner wall surface near the one end opening of the through hole;
the stator comprises: an outer peripheral fitting part, fitted into the protrusion; and a stator side receiving part, receiving the first annular seal member in cooperation with the bobbin side receiving part; and
the bobbin module and the stator define a communication path that communicates from an internal space of the through hole deviated from the protrusion to the first annular seal member in an assembled state in which the outer peripheral fitting part is fitted into the protrusion.
2 . The electromagnetic actuator according to claim 1 , wherein
the bobbin module comprises an annular tapered surface in an inner peripheral area of the one end opening of the through hole; and
the protrusion is formed in an area deviated from the annular tapered surface in the direction of the axis line.
3 . The electromagnetic actuator according to claim 1 , wherein
the stator comprises a first stator and a second stator arranged spaced apart in the direction of the axis line; and
the first annular seal member is arranged between the first stator and the bobbin module.
4 . The electromagnetic actuator according to claim 3 , wherein
the mover is provided with a buffer unit that absorbs impact upon the mover contacting the first stator and returning to a rest position.
5 . The electromagnetic actuator according to claim 3 , wherein
the first stator comprises: a cylindrical part, defining an inner peripheral surface that receives the mover; a bottom wall, blocking one end side of the cylindrical part and defining a rest position of the mover; and a flange, extending in a radial direction from the cylindrical part; and
the second stator comprises an insertion hole that receives the mover and exposes the mover at a tip thereof.
6 . The electromagnetic actuator according to claim 5 , wherein
the stator side receiving part is the flange; and
the bobbin side receiving part is an annular receiving part formed in the bobbin module to receive the first annular seal member in cooperation with the flange in the direction of the axis line.
7 . The electromagnetic actuator according to claim 5 , wherein
the mover comprises: a plunger, made of a magnetic material; and a shaft, made of a nonmagnetic material, fixed to the plunger, and exerting a driving force to the outside;
the second stator comprises: a stopper, defining an operating position of the mover; and a guide hole, slidably guiding the shaft;
the inner peripheral surface of the first stator receives the plunger in a non-contact manner to be capable of reciprocating; and
the insertion hole of the second stator receives the shaft in a non-contact manner to be capable of reciprocating.
8 . The electromagnetic actuator according to claim 3 , further comprising:
an outer magnetic path member, connected to the first stator and the second stator and forming a magnetic path.
9 . The electromagnetic actuator according to claim 8 , wherein
the outer magnetic path member comprises: a cylindrical member, connected to the first stator and surrounding the bobbin module; and a flat plate member, connected to the second stator and the cylindrical member.
10 . The electromagnetic actuator according to claim 9 , wherein
the flat plate member also serves as a flange member for attachment to an attachment object.
11 . The electromagnetic actuator according to claim 3 , wherein
the bobbin module comprises: a bobbin, defining the through hole and the protrusion; a coil for excitation, wound around the bobbin; and an outer cover member, covering the coil and in which a connector that surrounds a terminal connected to an end of the coil is formed.
12 . The electromagnetic actuator according to claim 11 , wherein
the bobbin side receiving part is formed in the outer cover member or the bobbin.
13 . The electromagnetic actuator according to claim 11 , wherein
a second annular seal member is arranged between the second stator and the bobbin.
14 . The electromagnetic actuator according to claim 11 , wherein
the bobbin comprises: a first positioning part, formed near the one end opening of the through hole in the direction of the axis line and positioning the first stator on the axis line; and a second positioning part, formed near the other end opening of the through hole in the direction of the axis line and positioning the second stator on the axis line; and
the protrusion is the first positioning part.
15 . The electromagnetic actuator according to claim 14 , wherein
the through hole comprises: a first through hole, centered on the axis line; and a second through hole, adjacent to the first through hole in the direction of the axis line and having a smaller diameter than the first through hole;
the first positioning part comprises, in an area of the first through hole, a plurality of ridges protruding from an inner wall surface of the first through hole and extending in the direction of the axis line; and
the communication path is defined by a recessed area between the plurality of ridges.
16 . The electromagnetic actuator according to claim 15 , wherein
the outer peripheral fitting part is fitted halfway into the first positioning part in the direction of the axis line.