An object of the present invention is to provide a construction machine that is equipped with a pressure accumulating device, which accumulates the return oil of an actuator, and that is capable of adjusting the operation speed of the actuator according to the revolution speed of a prime mover. For this purpose, in a construction machine including a prime mover, a revolution speed setting device that sets a revolution speed of the prime mover, an actuator, a pressure accumulating device that can supply and discharge a hydraulic fluid to and from the actuator, a first control valve disposed on a hydraulic fluid line that connects the pressure accumulating device and the actuator to each other, an operation device that gives an instruction for operation of the actuator, and a controller that is inputted with an operation signal of the operation device and outputs a control signal to the first control valve, the controller controls the first control valve according to an operation amount of the operation device and the revolution speed set by the revolution speed setting device.

The invention relates to a hydraulic drive system, to a method for adjusting a delivery volume in a hydraulic drive system, and to the use of the hydraulic drive system for controlling a hydraulic cylinder. The hydraulic drive system according to the invention is a hydraulic drive system with a first hydraulic machine and a second hydraulic machine which are connected mechanically to one another. The first hydraulic machine and the second hydraulic machine are operated jointly by a variable-speed drive. The first hydraulic machine and the second hydraulic machine are connected hydraulically to at least one first hydraulic cylinder, comprising a first hydraulic cylinder surface and a second hydraulic cylinder surface. The first hydraulic machine and/or the second hydraulic machine have/has an adjustable delivery volume.

The invention relates to a hydraulic drive system, to a method for adjusting a delivery volume in a hydraulic drive system, and to the use of the hydraulic drive system for controlling a hydraulic cylinder. The hydraulic drive system according to the invention is a hydraulic drive system with a first hydraulic machine and a second hydraulic machine which are connected mechanically to one another. The first hydraulic machine and the second hydraulic machine are operated jointly by a variable-speed drive. The first hydraulic machine and the second hydraulic machine are connected hydraulically to at least one first hydraulic cylinder, comprising a first hydraulic cylinder surface and a second hydraulic cylinder surface. The first hydraulic machine and/or the second hydraulic machine have/has an adjustable delivery volume.