Slewing system for hybrid hydraulic excavator and driving and braking method for slewing system

The invention discloses a slewing system for a hybrid hydraulic excavator and a driving and braking method for the slewing system, and belongs to the technical field of hydraulic systems of excavators. The invention solves the problem that the energy recovery efficiency is low when the conventional slewing system of the hybrid hydraulic excavator is braked. The slewing system comprises a variabledisplacement pump, a multiway valve, an electro-hydraulic proportional throttle valve, a one-way valve, an electric control switch valve, a first hand-operated direction valve, a second hand-operateddirection valve, an overflow valve, a hydraulic pump/motor, a hydraulic accumulator, a pressure sensor and a controller. Based on the driving and braking method for the slewing system, the first hand-operated direction valve is adjusted to an upper position and the second hand-operated direction valve is adjusted to a middle position, so that the slewing system enters a hybrid mode with an energyrecovery function, and the slewing system is driven and braked in the mode by utilizing the characteristic that the hydraulic pump/motor can work in four quadrants. The slewing system is suitable forthe hybrid hydraulic excavator.