Variable speed drive with two pumps and one differential cylinder

摘要

Disclosed is a linear actuator with a double pump and with a differential cylinder whose annular space or piston rod space is delimited by an annular surface or piston rod surface of a piston and is connected to a first pump, and whose piston crown space is delimited by a piston crown surface of the piston and connected to a second pump is. Both pumps are driven by a common variable-speed electric motor. The ratio of the ring area to the piston crown area is equal to the ratio of the delivery volume of the first pump to the delivery volume of the second pump. According to a first variant, this is achieved by adapting the speeds of the two pumps by means of a gear. According to a second variant, this is realized in that a pump is designed with an adjustable delivery volume. According to a third variant, this is achieved in that the ratio of the displacement volume of the pumps corresponds to the ratio of the cylinder areas at the same pump speed.