Patent ID: 6912849

Claim:
A cylinder driving system, comprising: a hydraulic cylinder; a hydraulic pump which comprises three suction/discharge ports including: (i) a first port for supplying oil to a bottom chamber of said hydraulic cylinder and for draining oil from said bottom chamber, (ii) a second port for draining oil from a head chamber of said hydraulic cylinder and for supplying oil to said head chamber, and (iii) a third port for draining oil from a tank and for supplying oil to said tank, wherein a suction rate in said first port is a sum of respective discharge rates in said second port and said third port, and a discharge rate in said first port is a sum of respective suction rates in said second port and said third port; and an electric motor for controlling a rotation speed and a rotation direction of said hydraulic pump; wherein the hydraulic pump comprises one of a swash plate pump and a bent axis pump; and wherein regenerated energy is recovered via the electric motor during regenerative braking of the hydraulic pump.