ELECTROHYDRAULIC DISPLACEMENT SERVO DRIVE Russian patent published in 2009 - IPC F15B9/03 

FIELD: engines and pumps.

SUBSTANCE: proposed servo drive is intended for automatic control purposes. The proposed drive incorporates an adjustable pump communicating, via hydraulic power lines, with the actuator hydraulic motor coupled, via a reduction gear, with the drive actuator shaft, and adding amplifier and hydraulic amplifier connected in series, the latter being connected to the cavities of power cylinders incorporated with the rotary adjusting member. The pump control member position pickup, power hydraulic line pressure pickups, the actuator position pickup and hydraulic motor RPM pickup are connected to the adding amplifier inputs. The drive is furnished with the pickups of working fluid temperature in power hydraulic lines, ambient air temperature pickup, processor and working fluid temperature setting and control amplifier connected to the temperature pickups and amplifier. A controlled throttle, connected to the processor, can be connected in between the cylinders spaces. The drive is provided also with the compressor with evaporator, condenser and adjustable RPM blowers, instantaneous radiator, instantaneous heaters and hydraulic control valve. The said instantaneous electric heaters are connected in series to the power hydraulic lines, while the evaporator and radiator, via three-way two-position hydraulic control valve, are connected in parallel to the power hydraulic line. The evaporator can realise heat exchange between the working surface and compressor coolant (Freon). Condenser and radiator are blown over by the aforesaid blowers. The control device output is connected to the processor, while the latter is connected to the hydraulic control valve switching drive, blower RPM control switch, electric heater ON/OFF circuit and compressor starter.

EFFECT: expanded temperature operating range, higher reliability, longer life thanks to stabilised properties of working fluid, higher accuracy, damping at stepwise loads and reduced scatter of operating performances at various ambient conditions.

5 cl, 1 dwg