| 摘要 |
PROBLEM TO BE SOLVED: To provide a brush, a commutator and a commutation mechanism that are superior in commutation properties and durability. SOLUTION: A commutator 5 in a DC electric motor has a plurality of commutator pieces 6 that comes into contact with a brush 4, each of the commutator pieces 6 a low resistance layer 61 made up of a low-resistance material, a high-resistance layer 62 made up of a high resistance material of which resistivity is higher than that of the low-resistance material. A low resistance material contains a carbon material and a binder, and a high-resistance material contains a carbon material and a binder and a boron nitride (BN) as an inorganic substance. The mixing ratio of boron nitride to the total quantity of the high resistance material is designed to be greater than 20 wt%. COPYRIGHT: (C)2006,JPO&NCIPI
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