Rotor shaft assembly

Abstract

There is provided improved balancing of a rotor shaft assembly (124) for a machine tool (100). The rotor shaft assembly (124) comprises an elongated body for forming a rotor axis (112), and a guiding portion for balancing the machine tool (100), arranged at an end of the elongated body. The guiding portion comprises a connector for a tool (110) or tool shaft (104) and an orbit path (117) that is concentric with a longitudinal direction of the elongated body and eccentric with respect to the connector for a tool (110) or tool shaft (104); wherein the guiding portion comprises two or more balancing bodies (126) arranged movable at the orbit path (117) in a plane that is parallel to a radial direction of the rotor shaft assembly (124).