| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent the fact that when a carbon brush is worn and energization force of a spring becomes weak, upon application of vibration occurred during use of a power tool onto a contact surface between the carbon brush and a commutator, a contact state therebetween is deteriorated, and an arc occurs on the contact surface between the carbon brush and the commutator, thereby causing melting and wear of a contact part, resulting in a short life of the carbon brush and the commutator. <P>SOLUTION: A permanent magnet 16 is disposed inside a carbon brush 8, and an iron sleeve 19 is disposed inside a commutator 18. Thereby, the carbon brush 8 is sucked toward a commutator 13 by suction force of the permanent magnet 16 and the iron sleep 19, thus allowing the carbon brush 8 and the commutator 18 to be maintained in a stable contact state. <P>COPYRIGHT: (C)2012,JPO&INPIT |
