Product Description:

The 1MR160D-A055 is a rotor component used within Bosch Rexroth Indramat’s 1MB High-Speed Asynchronous Motors series of frameless spindle drives. Supplied as a loose rotor, it is paired with a stator during machine tool assembly to create a compact, high-speed motor that transmits torque directly to the spindle. Integrating this rotor lets OEMs build spindles that maintain thermal separation between the stator and the machining zone while achieving the elevated surface speeds used in modern metal-cutting and grinding equipment.

The rotor geometry centers on an outside diameter of 106.5 mm, providing the magnetic air gap needed for the 1MB stator set. An inside rotor diameter of 55 mm leaves space for a drawbar or coolant tube without compromising structural rigidity. The spindle nose engages a precision-ground fit at 54.8 mm, so torque is transferred through an interference seat rather than keys. At the bearing location, the seat is machined to 106.3 mm with a negative allowance of -0.05 mm; this preload supports concentric running and limits vibration at the motor’s rated speed. These dimensions set the fit conditions for the shaft and bearing interfaces during spindle assembly.

A thread size of M6 is tapped in the balancing ring, allowing mass correction when the complete spindle is trimmed to grade G2.5 or better. The bore that mates to the shaft adheres to tolerance class H6, aligning with the interference strategy used in the rotor’s step design. A 30° entry chamfer eases assembly onto the shaft while minimizing scoring of the finely ground surfaces. The component belongs to frame size 160 and is marked with length code D, so users can match rotor mass and polar inertia to the corresponding stator segment without recalculating electromagnetic constants.