초록 ▼

There is provided an autonomous inverter-driven hydraulic unit in which a command pressure and command flow rate do not need to be inputted from outside and a pressure and flow rate can be autonomously controlled without requiring any input signal wire. A target horsepower calculation unit 25 of a c

There is provided an autonomous inverter-driven hydraulic unit in which a command pressure and command flow rate do not need to be inputted from outside and a pressure and flow rate can be autonomously controlled without requiring any input signal wire. A target horsepower calculation unit 25 of a controller 11 judges which of a plurality of regions a point representing a present operating state belongs to and calculates a target horsepower represented by a point on a target pressure-flow rate characteristic line based on the present pressure and present flow rate. A comparison unit 28 calculates a deviation of this target horsepower and a present horsepower received from a present horsepower calculation unit 26, inputs a control signal representing this deviation to the inverter 3 and controls a rotational number of a variable-speed motor 2 so that the present horsepower coincides with the target horsepower.

대표청구항 ▼

1. An autonomous inverter-driven hydraulic unit comprising: a hydraulic pump (1); a variable-speed motor (2) for driving the hydraulic pump (1); an inverter (3) for driving the variable-speed motor (2); a load sensor (6) for detection a load of the hydraulic pump (1); a rotation sensor (5) fo

1. An autonomous inverter-driven hydraulic unit comprising: a hydraulic pump (1); a variable-speed motor (2) for driving the hydraulic pump (1); an inverter (3) for driving the variable-speed motor (2); a load sensor (6) for detection a load of the hydraulic pump (1); a rotation sensor (5) for detecting a rotation speed of the variable-speed motor (2) or hydraulic pump (1); a controller (11) for outputting a control signal to the inverter (3) based on outputs from the load sensor (6) and rotation sensor (5) so that a pressure and flow rate of fluid discharged from the hydraulic pump (1) become a pressure and flow rate on a predetermined target pressure-flow rate characteristic line, the controller (11) having a target horsepower calculation unit (25) calculating a target horsepower based on the outputs from the load sensor (6) and rotation sensor (5) and the target pressure-flow rate characteristic line, a present horsepower calculation unit (26) calculating a present horsepower based on the outputs from the load sensor (6) and rotation sensor (5) and a comparison unit (27) comparing the target horsepower and the present horsepower and outputting the control signal to the inverter (3). 2. The autonomous inverter-driven hydraulic unit according to claim 1, wherein the target pressure-flow rate characteristic line is composed of a maximum flow rate (MV), maximum horsepower curve (MHP), and maximum pressure line (MP). 3. The autonomous inverter-driven hydraulic unit according to claim 1, wherein the load sensor is a current sensor for detecting current flowing to the variable-speed motor (2). 4. The autonomous inverter-driven hydraulic unit according to claim 1, wherein the load sensor (6) is a pressure sensor (6) for detecting a pressure in a discharge line of the hydraulic pump (1).