Hydraulic transmission unit for an actuator

An actuator device comprising:

• an actuator;
• and
• a hydraulic transmission unit mechanically connected in series to the actuator, which hydraulic transmission unit can be filled with hydraulic fluid, comprising:
• a first and a second chamber, which are hydraulically connected to each other and of which the first chamber is formed as a drive chamber and the second chamber is formed as an output chamber, the first chamber being coupled to the actuator,
• wherein a first piston is arranged movably along a piston axis at least in the first chamber such that this first piston separates the first chamber into a variable-volume first working chamber and a first rear-side chamber,
• wherein the first rear-side chamber is defined, at least in part, by a first lateral bounding wall that is subdivided into a first straight cylinder wall portion that axially transitions into a laterally delimiting first bellows element with variable axial length, the first straight cylinder wall portion and first bellows element collectively defining an outer boundary of the first rear-side chamber,
• wherein a second piston is arranged movably along a piston axis in the second chamber such that this second piston separates the second chamber into a variable-volume second working chamber and a second rear-side chamber;
• wherein the actuator device additionally comprises a reservoir chamber for the hydraulic fluid, which is fluidically coupled and/or capable of being fluidically coupled to at least one rear-side chamber;
• wherein the actuator device further comprises a hydraulic line fluidically coupling the variable-volume first working chamber to the variable-volume second working chamber, the reservoir chamber being separate from the hydraulic line.