Rotary percussive rock drill - separate rotary and percussive circuits, master valve adapts striker load to rotary pressure

摘要

A hydraulic drill motor (6) rotates together with a percussive motor whose striker (14) moves to and from the drill bit in active and idle strokes. The striker piston and housing together form a first pressure space (18) and second pressure space (20) to enclose the pressure fluid responsible for reciprocating the piston during drilling. Rotary and percussive motors each have their own hydraulics, with associated high and low pressure sides in the normal way. A fluid distribution valve (32) included in the percussive circuit always links one or other pressure space alternately with high and low pressure sides of the hydraulic system. The system has a master valve (42) to regulate the drive energy supplied to the striker through the distributor in accordance with the pressure obtaining on the high pressure side of the rotary motor circuit.