Polarized electromagnetic apparatus

• US 4,940,958 A
• Filed: 09/26/1989
• Issued: 07/10/1990
• Est. Priority Date: 09/29/1988
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Ootsuka, Shigeharu
• Primary Examiner(s): Broome, H.
• Application Number:
  US07/413,002
• Time in Patent Office: 287 Days
• Field of Search: 335/230, 335/229, 335/234, 335/236, 335/78, 335/79, 335/85
• US Class Current: 335/230
• CPC Class Codes: H01F 7/1646 Armatures or stationary parts of magnetic circuit having permanent magnet
• CPC Class Codes: H01H 51/2209 with rectilinearly movable armature

Abstract

The polarized electromagnetic apparatus consists of a stationary core assembly and a movable core assembly. The movable core assembly is made up of a movable core spindle and one movable core plate attached to one end surface thereof. Since the movable core assembly has only one movable core plate as opposed to two movable core plates in the conventional apparatus, the complete movable core assembly can be installed into the electromagnetic coil, facilitating the assembly work. A pole piece is mounted to the inner surface of the stationary cores on the side of the other end surface of the movable core spindle. The second end surface of the movable core spindle is inserted into the pole piece, so that an additional attractive force can be obtained. This construction makes the overall attractive force greater than can be obtained with the conventional apparatus.

Claims

1. A polarized electromagnetic apparatus having a movable core assembly, said core assembly being driven by a combined attractive force of a permanent magnet and an electromagnetic coil against a reset spring force when the electromagnetic coil is energized and said movable core assembly being driven by the reset spring force when the electromagnetic coil is de-energized, comprising:

at least one stationary core (1) having a substantially U-shaped cross section, said U-shaped cross section having a first leg and a second leg opposing each other and an inner surface;

a permanent magnet (7) having a first pole and a second pole, said first pole being in contact with said inner surface of said stationary core (1);

a pole plate (2) in contact with said second pole and forming a first clearance (P,Q) between said second leg;

an electromagnetic coil (6) disposed between said first and second legs;

a bar-shaped movable core (4) disposed between said first and second legs and movably extending through said electromagnetic coil (6), said bar-shaped movable core (4) having a first end and a second end, said bar-shaped movable core (4) having a movable core plate (5) which is secured at said first end of said bar-shaped movable core and extends into said first clearance (P,Q), said bar-shaped movable core (4) displaces in a longitudinal direction thereof to a first position where said movable core plane (5) is attracted by and contacts with said second leg when said electromagnetic coil (6) is de-energized and to a second position where said second end of said bar-shaped movable core (4) is attracted by and contacts with said first leg when said electromagnetic coil (6) is energized;

a pole piece (3) secured to said first leg and having a hole (20) therein through which said bar-shaped movable core (4) displaces to said second position.

2. A polarized electromagnetic apparatus according to claim 1, wherein said bar-shaped movable core (4) forms a second clearance (S) between said hole (20) in said pole piece (3) when said second end of said bar-shaped movable core (4) is attracted by and contacts with said first leg, and said bar-shaped movable core (4) forming a third clearance (R) between said first leg, said second clearance (S) being smaller than said third clearance.

3. A polarized electromagnetic apparatus having a movable magnetic core assembly, a magnetic stationary core, and an electromagnetic coil for magnetizing the movable magnetic core assembly, comprising:

at least one magnetic stationary core (1) having a substantially U-shaped cross section, said U-shaped cross section having a first leg and a second leg opposing each other;

an electromagnetic coil (6) disposed between said first and second legs;

a bar-shaped movable core (4) disposed between said first and second legs and movably extending through said electromagnetic coil (6), said movable bar-shaped magnetic core (4) having a cross sectional area;

a movable core plate (5) secured to one end of said bar-shaped movable core and is attracted by and contacts with said first leg through a contact area greater than said cross sectional area of said bar-shaped movable core (4) when said electromagnetic coil (6) is de-energized;

a pole piece (3) secured to said first leg and having a hole (20) therein through which said bar-shaped movable core (4) displaces as attracted by and contacts with said first leg when said electromagnetic coil (6) is energized.