Electromagnetic actuator

Patent metadata

Field	Value
Publication number	US-10902985-B2
Application number	US-201815955184-A
Country	US
Kind code	B2
Filing date	Apr 17, 2018
Priority date	Apr 27, 2017
Publication date	Jan 26, 2021
Grant date	Jan 26, 2021

Abstract

An electromagnetic actuator in which magnetic force from a permanent magnet causes a stator core and a first plunger to attract each other, and electromagnetic force generated by energizing an electromagnetic coil causes a mover to resist against the magnetic force from the permanent magnet to move in an axial direction separating from a front end portion of the stator core, wherein a ring member provided on the mover is inserted in the axial direction into a hole portion provided in a bottom wall member of a yoke, and an overlap size between the ring member and the bottom wall member is increased when the mover moves relative to the stator core in a separating direction, so that a magnetism transmission quantity from the permanent magnet passing through an overlap portion between the ring member and the bottom wall member is inhibited from being reduced.

First claim

What is claimed is:

1. An electromagnetic actuator, comprising:
a stator including a yoke with a housing space, a stator core provided in the housing space, and an electromagnetic coil disposed surrounding the stator core;
a mover including a permanent magnet and provided movably relative to the stator core in the housing space in an axial direction of the yoke, magnetic force from the permanent magnet causing the stator core and the mover to attract each other, and electromagnetic force generated by energizing the electromagnetic coil causing the mover to resist the magnetic force from the permanent magnet to move from the stator core in a separating direction; and
a magnetism transmission quantity adjusting portion provided at a position through which lines of magnetic force from the permanent magnet pass and configured to increase a magnetism transmission quantity from the permanent magnet when the mover moves relative to the stator core in the separating direction,
the magnetism transmission quantity adjusting portion is disposed at a different position from the electromagnetic coil in the axial direction of the yoke, and includes
a columnar ring member provided in the mover and protruding in the axial direction, and
an edge member of the yoke including a hole portion through which the ring member is inserted, the hole portion extending in the axial direction, wherein an inner circumferential surface of the hole portion is parallel to an outer circumferential surface of the ring member,

an insertion distance of the ring member relative to the hole portion changes in accordance with a movement position of the mover, so that a passage cross-sectional area of lines of magnetic force from the permanent magnet between the ring member and the edge member changes,
when the electromagnetic coil is not energized, the mover is located at a latched position having the edge member of the yoke and an outer circumferential surface of the ring member overlap parallel to the axial direction of the yoke and are adjacent to each other perpendicular to the axial direction of the yoke, and
in the latched position of the mover, a region where the edge member of the yoke and the outer circumferential surface of the ring member are adjacent to each other and overlap parallel to the axial direction of the yoke and are adjacent to each other perpendicular to the axial direction of the yoke is a region which has a smallest cross-sectional area of regions through which the lines of magnetic force from the permanent magnet pass.

2. The electromagnetic actuator according to claim 1 , wherein
the mover includes a plunger disposed facing the stator core in the housing space of the yoke, and
the ring member is formed to have a diameter smaller than a diameter of the plunger.

3. The electromagnetic actuator according to claim 1 , wherein a cylindrical-shaped body is provided between a surrounding wall member of the yoke and the mover, the body enclosing the housing space of the yoke including the mover and formed of non-magnetic material, and
the magnetism transmission quantity adjusting portion is disposed at a different position from the body in the axial direction of the yoke.

4. The electromagnetic actuator according to claim 2 , wherein a cylindrical-shaped body is provided between a surrounding wall member of the yoke and the mover, the body enclosing the housing space of the yoke including the mover and formed of non-magnetic material, and
the magnetism transmission quantity adjusting portion is disposed at a different position from the body in the axial direction of the yoke.

Assignees

• Mikuni Kogyo Kk

Inventors

• Ogasawara Toshiki

Classifications

• H01F2007/086

  Structural details of the armature · CPC title

• H01F7/128

  Encapsulating, encasing or sealing · CPC title

• F01L9/20

  by electric means · CPC title

• H01F7/081

  Magnetic constructions · CPC title

• H01F7/1646 Primary

  Armatures or stationary parts of magnetic circuit having permanent magnet · CPC title