| 摘要 |
A hydraulically driven downhole drill is provided with a drill connector (51) for simplifying both hydraulic circuits of a drill head (1) and a connecting rod (60) and adapting the hydraulic circuit arrangement of the drill head (1) with the other hydraulic circuit arrangement of the connecting rod (60). Use of this drill connector results in simplification of the circuit arrangement at the connecting portion between the drill head and connecting head. This downhole drill is further provided with an automatically-operated hydraulic pressure shut-off valve (65) at a connecting portion between the connecting rods (60) to prevent oil from leaking upon engagement and disengagement of the rods (60). The drill head (1) has a mechanism for reciprocating hydraulically a piston (8) controlled by a control valve (20) in the cylinder, and the piston (8) has a hydraulic circuit (50) for removing chips. The connecting rods (60) each have therein a high pressure hydraulic circuit (30) formed along the central axis, a low pressure hydraulic circuit (40) formed coaxially with the hydraulic circuit (30) around the outer periphery thereof, and pipes (61, 61a, 61b) including the hydraulic circuit (50) for removing chips. A pressure compensator can be mounted at the connecting portion of the drill head with the connecting rod and at the connecting portions of the connecting rods with each other. |
