US 11,808,736 B2
Fixing force evaluation method
Hiroaki Urano, Miyoshi (JP); and Akihide Shimmei, Okazaki (JP)
Assigned to TOYOTA JIDOSHA KABUSHIKI KAISHA, Toyota (JP)
Filed by TOYOTA JIDOSHA KABUSHIKI KAISHA, Toyota (JP)
Filed on Jul. 1, 2021, as Appl. No. 17/365,743.
Claims priority of application No. 2020-122438 (JP), filed on Jul. 16, 2020.
Prior Publication US 2022/0018813 A1, Jan. 20, 2022
Int. Cl. G01N 29/12 (2006.01); G01M 7/08 (2006.01); G01N 29/46 (2006.01); G01H 13/00 (2006.01); G01M 7/02 (2006.01); H02K 3/34 (2006.01); G01N 29/04 (2006.01)
CPC G01N 29/12 (2013.01) [G01H 13/00 (2013.01); G01M 7/02 (2013.01); G01M 7/08 (2013.01); G01N 29/045 (2013.01); G01N 29/46 (2013.01); G01N 2291/02827 (2013.01); G01N 2291/2693 (2013.01); H02K 3/345 (2013.01)] 3 Claims
OG exemplary drawing
 
1. A fixing force evaluation method for evaluating a fixing force of an insulating paper that has a foam adhesive layer on both sides, the insulating paper being interposed between a tooth portion provided on a stator core included in a stator and a coil wound around the tooth portion, the stator core including insertion holes formed in an end surface of the stator core, and the insulating paper fixing the tooth portion and the coil, the fixing force evaluation method comprising:
inserting fastening bolts into the insertion holes of the stator core to restrain an area directly below the fastening bolts by a table via a spring;
measuring a natural frequency of the stator in which the tooth portion and the coil are fixed by the insulating paper while the stator core is restrained by the table;
performing frequency analysis by using a fast fourier transform on a signal that is detected by an acceleration sensor provided at a predetermined second spot of the stator when the natural frequency is measured; and
evaluating that the fixing force of the insulating paper is large when the measured natural frequency of the stator is high, compared to when the natural frequency is low, the fixing force being evaluated as being high in a case where the natural frequency exceeds a threshold natural frequency, wherein
the frequency analysis is performed by exciting a predetermined first spot of the stator with a hammer, and a frequency in which a sound pressure level establishes the highest peak is set as the natural frequency of the stator, and
the predetermined first spot of the stator and the predetermined second spot of the stator are each peripheral portions of the insertion holes.