US 12,007,235 B2
Magnetic encoder
Ryuichi Masui, Bando (JP); and Naohiro Ishizawa, Tsukubamirai (JP)
Assigned to SMC CORPORATION, Chiyoda-ku (JP)
Appl. No. 17/633,822
Filed by SMC CORPORATION, Chiyoda-ku (JP)
PCT Filed Aug. 5, 2020, PCT No. PCT/JP2020/030068
§ 371(c)(1), (2) Date Feb. 8, 2022,
PCT Pub. No. WO2021/029305, PCT Pub. Date Feb. 18, 2021.
Claims priority of application No. 2019-148028 (JP), filed on Aug. 9, 2019.
Prior Publication US 2022/0299306 A1, Sep. 22, 2022
Int. Cl. G01B 7/30 (2006.01); G01D 5/20 (2006.01); G01P 1/02 (2006.01); G01P 3/487 (2006.01); G01P 3/488 (2006.01); G01D 5/14 (2006.01)
CPC G01B 7/30 (2013.01) [G01D 5/20 (2013.01); G01P 1/026 (2013.01); G01P 3/487 (2013.01); G01P 3/488 (2013.01); G01D 5/145 (2013.01); G01D 5/2013 (2013.01)] 6 Claims
OG exemplary drawing
 
1. A magnetic encoder having
a permanent magnet configured to rotate accompanying rotation of a rotating body constituting a rotational drive unit, and
a magnetic sensor configured to detect a change in a magnetic field of the permanent magnet,
the magnetic encoder comprising:
a first member including a first wall portion in which an insertion hole is formed through which the rotating body is passed; and
a second member including a second wall portion sandwiching the permanent magnet and the magnetic sensor between the second wall portion and the first wall portion,
wherein the first member and the second member are made of a mild steel containing up to 3.0% by weight of carbon, and
wherein a coercivity of the first member and the second member is less than or equal to 3 oersted.