| 摘要 |
<p>An impact drill 10 comprises a housing 20 having an accommodation chamber and a through hole 24 extending from the accommodation chamber to the outside space, and a driving mechanism 30 mounted in the accommodation chamber and having a transmission shaft 32 positioned in the through hole for providing an output torque and producing an impact force intermittently upon a resistance. A chuck unit 40, which has a drill chuck 41 that has connection barrel 441 defining a polygonal coupling hole (442, fig 4), is press-fitted onto polygonal front segment 324 of the transmission shaft. A first bearing 42 is mounted on the connection barrel and is received in the through hole to secure the drill chuck to the housing. Preferably, the through hole of the housing is stepped, and a larger diameter 243 segment accommodates the first bearing, and a smaller diameter segment 241 accommodates a second bearing 43.</p> |
