US 12,283,420 B2
Permanent electromagnetic holder and conveyance device
Yasuhiro Suzuki, Osaka (JP); and Kunio Ohhata, Osaka (JP)
Assigned to SIMOTEC CO., LTD., Higashiosaka (JP)
Appl. No. 17/917,402
Filed by SIMOTEC CO., LTD., Higashiosaka (JP)
PCT Filed Apr. 6, 2021, PCT No. PCT/JP2021/014575
§ 371(c)(1), (2) Date Oct. 6, 2022,
PCT Pub. No. WO2021/206074, PCT Pub. Date Oct. 14, 2021.
Claims priority of application No. 2020-071194 (JP), filed on Apr. 10, 2020.
Prior Publication US 2023/0154661 A1, May 18, 2023
Int. Cl. H01F 7/20 (2006.01); H01F 7/02 (2006.01); H01F 7/06 (2006.01); B66C 1/06 (2006.01)
CPC H01F 7/20 (2013.01) [H01F 7/0231 (2013.01); H01F 7/064 (2013.01); B66C 1/06 (2013.01)] 6 Claims
OG exemplary drawing
 
1. A permanent electromagnetic holder including an attracting surface for an object to be attracted, configured to be capable of attracting the object to be attracted in an attraction ON state, and configured to be capable of detaching the object to be attracted that has been attracted in an attraction OFF state, the permanent electromagnetic holder comprising:
a first magnet that is a magnet having a relatively small coercive force;
a second magnet that is a rare-earth magnet having a relatively large coercive force and is configured in a ring shape; and
a coil configured to magnetize the first magnet through energization of the coil,
the first magnet being configured such that magnetic pole surfaces of different magnetic poles are oriented in a thrust direction of an axial center orthogonal to the attracting surface and passing through a center of the attracting surface,
the second magnet being configured such that magnetic pole surfaces of different magnetic poles are oriented in the thrust direction of the axial center and being disposed outside the first magnet in a radial direction of the axial center,
the coil being disposed between the first magnet and the second magnet,
the first magnet, the second magnet, and the coil being arranged so as to overlap in the radial direction of the axial center, and
an operation of switching an attraction ON/OFF state being carried out by switching a magnetizing direction of the first magnet through instantaneous energization of the coil when the attraction ON/OFF state is switched.