| 摘要 |
<p>A compressor piston (154) divides a first compartment (153) into two compression chambers (155, 156), while a hammer piston (285) divides a second compartment (284) into two drive chambers (286, 287), each of the compression chambers (155, 156) being connected to a respective one of the drive chambers (286, 287) to form a closed fluid system wherein reciprocation of the compressor piston (154) causes cyclic compression and expansion of the fluid in the compression chambers (155, 156) and thus in the drive chambers (286, 287), to effect a cyclic impacting of the hammer piston (285) with a bit adapter (27) connected to the drill bit (14). A mud motor (16) rotates a shaft (68) to drive an oscillator (172) which reciprocates the compressor piston (154). The oscillator (172) can comprise roller elements (191-198) in the compressor piston (154) in engagement with canted grooves (181-184) in the shaft (68).</p> |
