Closed hydraulic circuit of hoisting winding engine

The invention relates to a closed hydraulic circuit of a hoisting winding engine. In the invention, a braking hydraulic pump is additionally arranged on the mechanical connection link of a diesel engine and a two-way hydraulic pump; the main shaft of the braking hydraulic pump, the main shaft of the two-way hydraulic pump and the main shaft of the diesel engine are connected in a mechanical transmission mode; the oil inlet of the braking hydraulic pump is connected with the oil outlet of a hydraulic oil tank so as to pump hydraulic oil from the hydraulic oil tank; and the oil extraction of the braking hydraulic pump is connected to the hydraulic oil tank through an overflow valve. By measuring the revolution increment of the diesel engine dragged by the driving torque of the two-way hydraulic pump and controlling the throttling actions of the braking hydraulic pump and the overflow valve, the invention ensures that the driven torque produced by the braking hydraulic pump is balanced with the driving torque pr