| 摘要 |
PROBLEM TO BE SOLVED: To perform heat radiation of a brake device with a simple structure in a chain saw.SOLUTION: In a chain saw, a saw chain is driven to circulate along an outer periphery of a guide bar by rotation of a drive shaft when a trigger switch points out an operation, and the rotation of the saw chain is stopped by braking the rotation of the drive shaft by the brake when the trigger switch points out a stop. A back plate of a centrifugal fan fixed to the drive shaft so as to be adjacent to a brake drum fixed to the drive shaft includes a first opening passing through the back plate at a position adjacent to an outer periphery of the brake drum. A bearing housing bearing the drive shaft on an opposite side of the fan back plate includes a second opening passing through a space on an opposite side of the brake drum. |
