| 摘要 |
PROBLEM TO BE SOLVED: To provide a brushless motor which can have high output, while being small in size by increasing the heat dissipation efficiency of an output element. SOLUTION: A circuit board 12, mounted with an exciting circuit for supplying exciting current to a stator 2, is mounted on a motor holder 1. The motor holder 1 is also mounted with a lower case 17. In a storing section 18 formed between the lower case 17 and the motor holder 1, the circuit board 12 is stored. An output element 21 for generating an exciting current is mounted with a heat sink 22, and a part of the heat sink 22 is exposed on the upper face of the motor holder 1 near a rotor. A fan 11 is rotated with the rotation of the rotor 6 to blow air. Air guide holes 28, 29 for generating air flow, which starts from outside the storing section 18 and returns to outside the storing section 18 via the heat sink 22 in the storing section 18 are formed either in the motor holder 1 or the lower case 17 or in both of them. |
