HYDRAULIC ASSEMBLY Russian patent published in 2016 - IPC E21B23/14 E21B4/18 

FIELD: mining.

SUBSTANCE: invention relates to a downhole tool, comprising: a hydraulic assembly, an arm assembly, comprising a wheel, a hydraulic motor for rotating wheel, thereby driving downhole tool in a forward direction, and a hydraulic pump unit for simultaneous generation of a first and a second pressurised fluid. Arm assembly is movable between a retracted position and a projecting position in relation to tool housing. Downhole tool furthermore comprises an arm activation assembly for moving arm assembly between retracted position and projecting position. Hydraulic motor drives downhole tool in forward direction when arm assembly is in projecting position. Arm actuation assembly is in fluid connection with first pressurised fluid and hydraulic motor is in fluid connection with second pressurised fluid, a hydraulic control block for controlling pressure of first pressurised fluid having a first pressure and controlling a second pressure of second pressurised fluid. Hydraulic control block comprises a first sequential valve for controlling a sequence of retraction of arm assembly, a projection of arm assembly and a rotation of wheel. Sequential valve is fluidly connected with one of fluids and changes between an open and a closed position based upon pressure of other fluid.

EFFECT: technical result is improved reliability of delivering downhole tool.

15 cl, 8 dwg