Hydraulic Drive System Having a 2X2Q Pump Unit

A hydraulic drive system for operating a hydraulic cylinder in a first movement profile and in a second movement profile, the system comprising:

• a hydraulic cylinder including a first cylinder chamber and a second cylinder chamber;
• a first fluid-hydraulic reservoir;
• a hydraulic drive unit having a first hydraulic machine having a first connection and a second connection and a second hydraulic machine having a first connection and a second connection;
• a first controllable valve, wherein the first controllable valve creates a fluid-hydraulic connection between the first cylinder chamber of the hydraulic cylinder and the first fluid-hydraulic reservoir in accordance with a movement profile;
• a second controllable valve, wherein the second controllable valve creates a fluid-hydraulic connection between the second connection of the second hydraulic machine and the second cylinder chamber of the hydraulic cylinder or with the first connection of the first hydraulic machine in accordance with the movement profile;
• wherein the first hydraulic machine and the second hydraulic machine are mechanically interconnected and are operated jointly by a variable-speed drive;
• wherein the second connection of the first hydraulic machine and the first connection of the second hydraulic machine are fluid-hydraulically connected to the first fluid-hydraulic reservoir;
• wherein, in the first movement profile, the first cylinder chamber is fluid-hydraulically connected to the first fluid-hydraulic reservoir and the second cylinder chamber is fluid-hydraulically connected to the second connection of the second hydraulic machine;
• and
• wherein, in the second movement profile, the first connection of the first hydraulic machine is connected to the second connection of the second hydraulic machine.