The invention discloses a hydro-electric mixed driving
system used for
engineering machinery, which comprises a
pilot control valve, a main valve, a
motive power device and a controller. The invention is characterized in that the
motive power device is a mixed
motive power device, and consists of a
hydraulic motor, a
motor generator and a speed reducing
machine through coaxial connection, an electromagnetic overflow valve is respectively connected in parallel on the high-pressure oil output end of the
hydraulic motor, the controller controls the
motor generator, the
electricity generation output of the
motor generator is connected with an energy accumulator, the output end of the energy accumulator is connected with the electric input end of the motor generator, an
electromagnetic valve block is arranged between the
pilot control valve and the main valve, a
pressure sensor is respectively arranged on the input and output end of the
electromagnetic valve block and on a high-pressure oil inlet opening of the
hydraulic motor, and each pressure
signal is respectively input into the controller. The hydraulic motor and the motor generator of the invention are in coaxial connection, the braking overflow energy is recovered to be used as
electric energy of the
electric motor, the hydro-electric mixed driving on the
engineering machinery is realized, the
energy consumption of the wholemachine is lowered, and the use cost is saved.