GB1358162A - Hydraulic motors for rock drills - Google Patents

Abstract

1358162 Rotary hydraulic motors W MAYALL 22 June 1971 [30 June 1970 30 April 19711 31751/70 and 12446/71 Heading F1F [Also in Division F2] A motor for a rock drill is energized by drilling mud and has a housing with an end fitting 2 by which it can be fixed to the lower end of a drilling string, bearing sleeves 42, 43, seal structures 44, 105, 112 and bearings 108..111 for rotary shafts 5, 37 being fed with grease from a stationary cylinder 27 by mud pressure acting on a piston 33 through a passage 32. The mud passes down the string and through the housing to the drill by way of a rotary end fitting 8. A valve 10 allows the mud to escape through an opening 17 until its pressure rises to a required value. The grease flows to the sleeves 42, 43 and seal structure 44 between a fixed sleeve 28 and an end cap 38 of the shaft 37, and to the seal structures 105, 112 and bearings 108..111 by way of a bore 41 and tube 106. A vent 127 allows air displaced by the grease to escape. A plug 133 facilitates injection of fresh grease. Mud pressure acting on the seal structures through a passage 58, bore 59 and tube 107 prevents leakage of grease therefrom. A "drive assembly" of the motor includes blades 62 that pivot on studs 63 in a ring 64 against the action of torsion shafts 73 in a rotor member 60, the latter and said ring being attached to the shafts 5, 37. It is indicated (in the Specification) that because each torsion shaft has a portion 76 abutting a wear piece 77 in the member 60 mud pressure in an annular space 80 makes the blades turn so as to bear upon the shaft 37, Figs. 3 and 6 (not shown), and effect continuous rotation of the rotor member and shafts 5, 37. Mud flows from the space 80 to the interior of the shaft 5 through passages 90, 91, 94, the passages 90 coming into register with the passages 91 when the blades approach the shaft 37. The pressure loss at the passages 90, 91 is said to cause the expenditure of energy necessary to drive the motor. A passage 86 equalizes pressures in spaces. (For Figures see next page)