Drive Device for a Joint of a Robot Arm, Associated Robot Arm, and Corresponding Rotary Feedthrough

Drive device (4) for a joint (L) of a robot arm (3), having:

• a motor (9) having a motor housing (6) and a hollow motor shaft (10) rotatably mounted in the motor housing (6),
• a gearing (13), arranged coaxially with the motor shaft (10), having a hollow gearing input element (14) coupled to the motor shaft (10), a hollow gearing output element (15), and a support element (16) coupling the gearing input element (14) to the gearing output element (15),
• a cable guide tube (17), connected to the gearing output element (15), which extends axially from its gearing-side tube end (17a) from the gearing output element (15) through the hollow motor shaft (10) to its motor-side tube end (17b) of the motor housing (6) which is axially opposite the gearing (13), and forms a guide tube end portion (18) there,
• a driver (19), connected to the guide tube end portion (18) of the cable guide tube (17), which has a hub portion (19a) connected to the guide tube end portion (18), a cable guide portion (19b) offset radially outwards, and a connecting portion (19c) connecting the hub portion (19a) to the cable guide portion (19b),
• an annular space (R), arranged coaxially with the motor (9), which is designed to accommodate a cable loop (7a) of a cable (7) inserted into the annular space (R), wherein the annular space (R) has an opening (20) through which the cable (7) can be fed into the annular space (R), wherein the cable guide portion (19b) of the driver (19) is designed, in an inserted state of the cable (7) in which the cable (7) is guided axially from the gearing-side tube end (17a) to the motor-side tube end (17b) through the cable guide tube (17) and is guided radially to the cable guide portion (19b), to entrain the cable (7) into the opening (20) of the annular space (R) in a transition portion (7c) of the cable (7) when the gearing output element (15) is rotated, such that the cable (7) is guided into the annular space (R) at a circumferential point corresponding to the current rotational position of the gearing output element (15).