US 11,868,123 B2
Abnormality diagnostic device for feed axis mechanism
Takumi Hongo, Niwa-Gun (JP)
Assigned to Okuma Corporation, Niwa-Gun (JP)
Filed by OKUMA CORPORATION, Niwa-Gun (JP)
Filed on Apr. 20, 2022, as Appl. No. 17/659,872.
Claims priority of application No. 2021-076681 (JP), filed on Apr. 28, 2021.
Prior Publication US 2022/0350322 A1, Nov. 3, 2022
Int. Cl. G05B 23/02 (2006.01); B23Q 17/00 (2006.01); G05B 19/404 (2006.01); B23Q 17/12 (2006.01); B23Q 5/40 (2006.01)
CPC G05B 23/0235 (2013.01) [B23Q 5/40 (2013.01); B23Q 17/007 (2013.01); B23Q 17/008 (2013.01); B23Q 17/12 (2013.01); G05B 19/404 (2013.01)] 4 Claims
OG exemplary drawing
 
1. An abnormality diagnostic device for a feed axis mechanism diagnosing an abnormality occurrence and an abnormal portion of the feed axis mechanism, the feed axis mechanism transmitting a rotation of a motor to a ball screw coupled by a coupling to rotate the ball screw, the abnormality diagnostic device comprising:
a resonance frequency measuring unit that measures a resonance frequency at a plurality of stroke positions within a stroke range of the feed axis mechanism; and
a diagnosis unit that identifies the abnormal portion based on a relationship between the stroke positions and change amounts relative to a standard value of the measured respective resonance frequencies; and
wherein when the change amount relative to the standard value of at least one of the resonance frequencies measured at two stroke positions exceeds a preset abnormality existence determination threshold, the diagnosis unit determines that there is an abnormality in the feed axis mechanism, and
when the abnormally is determined to be in the feed axis mechanism, the diagnosis unit obtains a difference between the change amount relative to the standard value of the resonance frequency measured at the stroke position on a coupling joining side and the change amount relative to the standard value of the resonance frequency measured at the stroke position on a counter coupling joining side, and the diagnosis unit diagnoses the abnormality in the feed axis mechanism as an abnormality of the coupling when the difference exceeds a preset abnormal portion identification threshold, and diagnoses as the abnormality in the feed axis mechanism as an abnormality of the ball screw when the difference is less than or equal to the preset abnormal identification threshold.