PUMP HYDRAULIC DRIVE Russian patent published in 2009 - IPC F04B49/00 

FIELD: engines and pumps.

SUBSTANCE: pump hydraulic drive comprises pump of controlled capacity and hydraulic reservoir with excess pressure of working fluid, which are connected by hydraulic lines to actuating hydraulic cylinders. Hydraulic lines of working fluid supply and drainage are equipped with external discharge and suction valves. In hydraulic reservoir body compensating device is located, which comprises piston that on one side forms air cavity communicating to atmosphere, and on the other it is connected to plunger and forms cavity for working fluid. Plunger is arranged as hollow, and is stepped from the outside, forming control chamber in hydraulic reservoir body between ends of plunger moving step and one of thrusts, and control chamber communicates to cavity in plunger via throttling opening in plunger wall. Cavity in plunger is limited by check air valve at the end, through which gas is supercharged into cavity and control chamber. On the opposite end of plunger and near second thrust air cavity is formed that communicates to atmosphere via gap between opening in thrust and plunger. Relief valve is inbuilt into supply hydraulic line, being installed in wall of cavity for working fluid, connected by its one outlet to cavity for working fluid and by its other outlet - to drainage.

EFFECT: more reliable start-up and operability of hydraulic drive.

18 cl, 3 dwg