Hydraulic operational system for an injection molding machine

A hydraulic operational system for an injection molding machine, comprising:

• a hydraulic line network;
• a plurality of hydraulic drives having different displacements for intermittently driving different components of the injection molding machine during operation of the machine;
• a plurality of directional control valves, which correspond to the plurality of hydraulic drives, for connecting the hydraulic drives with the network.
• a constant delivery pump for supplying the hydraulic line network with hydraulic fluid, the constant delivery pump being selected so that it is capable to provide at least one of a delivery volume of the hydraulic fluid and a hydraulic fluid pressure corresponding, respectively, to a least one of a maximum amount of the hydraulic fluid and a maximum pressure of the hydraulic fluid required for operating all of the plurality of hydraulic drives;
• an electric motor for driving the constant delivery pump;
• and
• wherein a maximum driving speed of the steplessly regulated electric motor is controlled so that the maximum driving speed corresponds to the hydraulic pump operation at which the hydraulic pump provides the at least one of a delivery volume and a hydraulic fluid pressure corresponding to the at least one of a maximum amount of the hydraulic fluid and the maximum pressure of the hydraulic fluid required for operating all of the plurality of hydraulic drives, and
• wherein a speed of the electric motor is controlled proportional to at least one of an amount of the hydraulic fluid and a pressure of the hydraulic fluid required for operating hydraulic drives actuated at a particular time.