| 摘要 |
<p>An impact wrench includes a motor portion, a clutch hammer portion, and an anvil portion. The motor portion includes a rotor (13) which is supported within a cylinder (15) for rotation in forward and reverse directions, and a plurality of rotor blades (14a - 14f) which are radially arrayed so as to be movable in the radial direction. The clutch hammer portion is coupled with a drive shaft of the rotor. The anvil portion which receives a hitting force from the clutch hammer portion so as to rotate. The cylinder (15) is provided with an air inlet hole (15a) for forward rotation and another air inlet hole (15c) for reverse rotation. The air inlet holes (15a, 15c) penetrate the cylinder in the axial direction and are symmetrically arranged on both sides with respect to the center axis of the cylinder (15). The cylinder (15) is also provided with an air outlet hole (15b) which is formed at a location shifted from the top by an angle &thetas; in a direction toward the air inlet hole (15a) for forward rotation. This structure makes it possible to loosen a threaded member easily through application of a loosening torque that is larger than tightening torque. <IMAGE></p> |
