High-low double-speed pressurizing system of rotary drilling rig

The utility model provides a high-low double-speed pressurizing system of a rotary drilling rig, which relates to a hydraulic system used for controlling a power unit of the rotary drilling rig to lead the power unit to be capable of pressurizing with low speed and accelerating with high speed. The utility model aims at providing the high-low double-speed pressurizing system of the rotary drilling rig, which has simple structure and convenient operation, and comprises a pressurizing control handle, a switch valve, a main hydraulic circuit with larger output flow, an auxiliary hydraulic circuit with smaller output flow, and a pressurizing oil cylinder or a pressurizing winch, wherein the main hydraulic circuit and the auxiliary hydraulic circuit are connected in parallel and then are connected with the pressurizing oil cylinder or the pressurizing winch; a control button on a pressurizing operation handle can control a three-station four-way valve in the main hydraulic circuit or the auxiliary hydraulic circuit so as to lead a hydraulic pump to supply oil for the pressurizing oil cylinder or the pressurizing winch; when a main hydraulic pump supplies oil for the pressurizing oil cylinder or the pressurizing winch, the pressurizing oil cylinder or the pressurizing winch can be promoted rapidly; and when an auxiliary pump supplies oil for the pressurizing oil cylinder or the pressurizing winch, the pressurizing oil cylinder or the pressurizing winch can be pressurized with low speed.