Direct-drive vs. geared rotary servomotor: A quantification of design advantage: Part 3

摘要

In the world of industrial automation, direct-drive motors and gear servomotors are frequently quoted against one another for similar applications. This overlap often causes confusion about which motor type is best suited for a particular axis. As direct-drive servomotors become more common, with a wider range of sizes and features, direct-drive servomotors are finding homes in more applications. A direct-drive servomotor is designed to accommodate the load mounted directly to the rotating flange of the motor. To accomplish this, the motors are designed with large, high-capacity bearings designed to carry the load without using additional support or bearings. Directly coupling the load to the motor also eliminates the backlash and torsional flex that can negatively impact the performance of a traditional rotary servomotor and gearbox combination. This simplified mechanical design, seen in Figure 1, lends itself to space-constrained situations such as robotic arms or a 4th or 5th axis on a computer numerical control (CNC) or additive manufacturing machine, where the space savings can reduce overall size and mass, improving system performance and reducing cost.