US 12,409,507 B2
Expulsion detection method in electric resistance welding and apparatus therefor
Yasuyuki Tanaka, Hiroshima (JP); Akira Nawahara, Hiroshima (JP); Daisuke Nakazaki, Hiroshima (JP); and Yohei Shoji, Hiroshima (JP)
Assigned to MAZDA MOTOR CORPORATION, Hiroshima (JP)
Appl. No. 17/433,025
Filed by MAZDA MOTOR CORPORATION, Hiroshima (JP)
PCT Filed Feb. 13, 2020, PCT No. PCT/JP2020/005611
§ 371(c)(1), (2) Date Aug. 23, 2021,
PCT Pub. No. WO2020/175158, PCT Pub. Date Sep. 3, 2020.
Claims priority of application No. 2019-031486 (JP), filed on Feb. 25, 2019.
Prior Publication US 2022/0152727 A1, May 19, 2022
Int. Cl. B23K 11/25 (2006.01); B23K 11/11 (2006.01); B23K 31/00 (2006.01); B23K 101/00 (2006.01)
CPC B23K 11/256 (2013.01) [B23K 11/115 (2013.01); B23K 31/003 (2013.01); B23K 2101/006 (2018.08)] 20 Claims
OG exemplary drawing
 
11. An expulsion detection apparatus in electric resistance welding for welding plural metal plates by energizing a workpiece, which is formed by superimposing the plural metal plates, by a pair of electrodes while pressurizing, the expulsion detection apparatus in the electric resistance welding comprising:
data accumulation means that detects an energization resistance reduction amount between the pair of electrodes at a specified time interval during each welding process under a specified welding condition and accumulates data on said energization resistance reduction amount;
frequency distribution calculation means that calculates frequency distribution of the energization resistance reduction amount under said welding condition on the basis of the data in the data accumulation means; and
determination means that fits frequency distribution, which is calculated by the frequency distribution calculation means, with a Gaussian function and determines occurrence of expulsion under said welding condition based on said fitting.