Product Description:

The 1MR270C-A120/S042 rotor is produced by Bosch Rexroth Indramat for the 1MB High-Speed Asynchronous Motors series. The part serves as the rotating core in frameless spindle motors, converting stator-generated magnetic fields into mechanical torque for high-speed machining, positioning, and similar automation tasks. Supplied as a separate rotor assembly, it can be paired with a compatible stator to create a compact spindle layout while allowing the surrounding machine structure to provide the bearing support and housing integration.

The rotor is sized for a frame designation of 270, and its laminated core measures 240 mm in length, which sets the magnetic path and torque capacity. An inside bore of 120 mm matches hollow-shaft clamping systems, while the bore fit tolerance of H6 supports precise radial alignment with the stator carrier. Dynamic balancing weights can be added through the balance thread of M6, which helps control vibration at the high operating speeds typical of this motor family. Motor length code C indicates a mid-length rotor variant, and the two pole-pair layout establishes the electrical frequency relationship during operation. Oil is supplied through a stepped interference-fit connection, and the same geometry secures the rotor on the shaft without keys.

System dynamics are influenced by a rotational inertia of 0.258 kgm², allowing rapid acceleration while still smoothing short load spikes. The overall rotor length is 328 mm, which provides adequate axial overlap with the stator windings and supports heat transfer along the shaft. A mass of 52 kg adds stiffness against bending at elevated speeds. Retention screws that conform to the DIN 913 standard fasten the threaded pins used to lock balancing weights in place, helping the rotor remain stable during repeated speed changes.