US 11,929,640 B2
Stator, movement, timepiece, method for manufacturing movement and method for manufacturing stator
Kosuke Yamamoto, Chiba (JP); Shinji Kinoshita, Chiba (JP); Hitoshi Takeuchi, Chiba (JP); and Tatsuya Omura, Chiba (JP)
Assigned to SEIKO INSTRUMENTS INC., Chiba (JP)
Filed by Seiko Instruments Inc., Chiba (JP)
Filed on Sep. 16, 2020, as Appl. No. 17/022,918.
Claims priority of application No. 2019-172905 (JP), filed on Sep. 24, 2019.
Prior Publication US 2021/0091607 A1, Mar. 25, 2021
Int. Cl. H02K 1/14 (2006.01); G04C 3/14 (2006.01); H02K 15/02 (2006.01); H02K 37/16 (2006.01); G04C 3/12 (2006.01)
CPC H02K 1/143 (2013.01) [G04C 3/14 (2013.01); H02K 15/022 (2013.01); H02K 37/16 (2013.01); G04C 3/12 (2013.01)] 9 Claims
OG exemplary drawing
 
1. A stator for a timepiece movement, comprising:
a stator plate having a first surface and a second surface opposite to the first surface, wherein the stator plate is made with magnetic material and has a circular hole for holding a rotor in the circular hole; and
two non-magnetic regions formed around the circular hole at a 180-degree interval between the circular hole and respective peripheries of the stator plate adjacent to the circular hole, wherein the two non-magnetic regions include chromium at a weight ratio of 15 wt % or more that is heat-diffused into the stator plate from the first surface of the stator plate in such a manner that the two non-magnetic regions each have a width that becomes progressively narrower from the first surface of the stator plate toward the second surface thereof, wherein the two non-magnetic regions each have a chromium bulge protruding from the first surface of the stator plate.