| 摘要 |
A device for use in underground drilling comprising: a tubular housing, a down-hole motor mounted within the housing and having an output shaft, means for connecting said output shaft to a drill bit, means for connecting said housing to a drill string, first and second stabilizers mounted on said housing, said first stabilizer being mounted nearer than the second stabilizer to the output shaft connecting means, at least one of said stabilizers being an eccentric stabilizer, and at least one stress relieving means between the first stabilizer and the means for connecting the housing to the drill string.
|
