US 12,247,951 B2
Detection system and detection method
Takahiko Irie, Tokyo (JP); Shigenori Inamoto, Tokyo (JP); and Kenta Ueda, Tokyo (JP)
Assigned to MITSUMI ELECTRIC CO., LTD., Tokyo (JP)
Filed by MITSUMI ELECTRIC CO., LTD., Tokyo (JP)
Filed on Dec. 30, 2021, as Appl. No. 17/646,643.
Application 17/646,643 is a continuation of application No. 16/609,195, granted, now 11,249,052, previously published as PCT/JP2018/013498, filed on Mar. 29, 2018.
Claims priority of application No. 2017-090620 (JP), filed on Apr. 28, 2017.
Prior Publication US 2022/0120716 A1, Apr. 21, 2022
Int. Cl. G01N 29/12 (2006.01)
CPC G01N 29/12 (2013.01) 13 Claims
OG exemplary drawing
 
1. A detection system for detecting a state change of an inspection target, comprising:
a sensing device including:
a vibration unit for applying vibration to the inspection target, the vibration unit configured to be attached to the inspection target,
a driving circuit for supplying an electrical signal to the vibration unit for driving the vibration unit, and
a sensor for detecting vibration of the inspection target caused by the vibration applied from the vibration unit; and
a detection processing device for receiving vibration information related to the vibration of the inspection target detected by the sensor from the sensing device, calculating a coherence between vibration of the vibration unit and the vibration of the inspection target, and detecting the state change of the inspection target based on the vibration information when the coherence is equal to or more than 0.5,
wherein the vibration unit of the sensing device includes:
a case in form of a cylindrical member having a cover, a base which is configured to be attachable to the inspection target, and a cylindrical portion located between the cover and the base,
a coil fixedly attached on an upper surface of the base and in which the electrical signal supplied from the driving circuit flows,
a leaf spring provided so as to be capable of vibrating with respect to the case, and
a magnet assembly having a magnet holding portion having a cylindrical body portion and an upper plate provided on an upper end of the cylindrical body portion and a magnet fixed on a lower surface of the upper plate, and the magnet assembly attached to the leaf spring so as to be apart from the coil,
wherein the case contains the coil, the leaf spring, and the magnet assembly therein,
wherein the leaf spring has a ring shape with an outer peripheral portion held between the base and the cylindrical portion of the case, and a central portion containing a central opening portion,
wherein the magnet assembly is attached to the central portion,
wherein the central portion can vibrate with respect to the base so that the magnet assembly can vibrate with respect to the coil,
wherein the sensor is an acceleration sensor configured to be provided on the inspection target for detecting the vibration of the inspection target, and
wherein a lower end of the cylindrical body portion of the magnet holding portion is fixed on an upper surface of the central portion of the leaf spring.