公开(公告)号：JPH09154261A

公开(公告)日：1997-06-10

申请号：JP1402196

申请日：1996-01-30

Applicant: DENSO CORP

Inventor： MATSUMOTO TATSUYA ,  ONISHI SHUNSAKU ,  EBIHARA YOSHIO ,  KIYOSE KENZO

IPC: F02M37/08 ,  H01R39/02 ,  H01R39/06 ,  H02K3/44 ,  H02K5/12 ,  H02K13/00 ,  H02K23/00

Abstract: PROBLEM TO BE SOLVED: To prevent the break of a pig tail by maintaining the insulation between a commutator and each segment with simple constitution. SOLUTION: A commutator made of copper 40, which is divided into eight segments 41, is provided on the side of the shaft 23 of a rotor 20. Tin (Sn) plating is applied on the edges of the respective segments 41 in the circumferential direction. Therefore, the formation of conductive copper sulfide at the above described edges caused by the reaction between the sulfur component contained in the fuel and the segments made of copper 41, is prevented. Therefore, the electric connection of the respective segments 41 is prevented, and the normal operation of the rotor 20 can be maintained. Since tin plating is performed to the copper pig tail of a brush and copper powder, which attaches the pig tail to the brush, the disconnection of the pig tails or the separation of the brush and the pig tail or the defective conduction caused by the reaction between the sulfur component in the fuel and the pig tail or the copper podder can be prevented.