Harmonic Drive
SCARA Robot Primary Axes
Low inertia Wave Generator
Integrated output bearing
SCARA robots for fast assembly tasks are an ideal application area for Harmonic Drive® gears. High dynamic performance dictates the use of compact, lightweight gears and the high accuracy required for accurate assembly necessitates gears with excellent repeatability. These selection criteria lead almost all of the world's leading SCARA robot manufacturers to use Harmonic Drive® gears in their designs. This design example shows a very compact and elegant design incorporating HFUS-2SS "Simplicity Units".
In the shoulder joint the outer ring of the cross-roller bearing is connected directly to the upper robot arm segment, while the Circular Spline is connected to the base. In the elbow joint the Circular Spline is connected to the lower arm segment. The elbow-axis gear features a special low inertia wave generator design, which "solid" Wave Generator design does not possess the Oldham coupling of the standard Wave Generator and therefore requires better motor shaft tolerances (DIN 42955 "R" tolerance class). However, the moment of inertia is up to 40% lower than that of the standard design. This can help to improve the dynamic performance of the robot. This design example shows that both Flexspline and Circular Spline can be used as output element.
