Abstract: A downhole closed-loop anti-tilting tool includes a housing; a rotating impeller and hydraulic pump; recessed parts spaced circumferentially on the housing's outer surface; a plunger and push plate; and multiple hydraulic flow paths arranged circumferentially in the housing, each path communicating the pump with a corresponding recessed part. An eccentric flow-dividing disc lies across the flow paths. The disc's outer circumference has a notch permitting one flow path to open, with the notch and the disc's center of gravity located opposite each other. The disc rotates about the axis. When the housing becomes inclined, gravity turns the disc so the notch moves to a higher position and the center of gravity to a lower position, thereby connecting one hydraulic flow path and disconnecting the others. The associated plunger and push plate then move radially outward. The tool contains no electronic components, and functions in all temperature wells.