Product Description:

The 1MR310D-A125 rotor is supplied by Bosch Rexroth Indramat as a component in the 1MB High-Speed Asynchronous Motors series. It functions as the rotating element of a frameless spindle motor and is intended to be press-fitted into a precision stator housing where it turns at elevated surface velocities to drive machining spindles in industrial automation. By forming the motor’s kinetic core, the rotor converts electromagnetic induction into mechanical rotation and stores energy that helps stabilize cutting speed during heavy load changes. Because it is a separate rotor component, it must be integrated accurately with the matching stator and spindle assembly for reliable high-speed operation.

With a frame size of 310, the rotor’s outside envelope matches the largest stator modules in the series, giving a wide magnetic air-gap surface. The inside rotor diameter of 125 mm provides clearance for the spindle shaft and leaves room for through-coolant passages. A rotor inertia of 0.492 kg·m² provides a flywheel effect that smooths torque ripple during rapid tool engagement. The component’s mass of 71.9 kg must be considered when calculating bearing preload and acceleration profiles. Its protection rating of IP00 indicates that no separate enclosure is supplied, so the surrounding motor housing must provide the enclosure and the required cooling path.

The motor uses length code D, which gives a medium axial length that balances torque capability against inertia within the 1MB series. Because the motor principle is Asynchronous, the laminated stack and squirrel-cage conductors are optimized for induction currents rather than permanent-magnet excitation. Secure seating comes from a rotor design with a step interference fit, enabling press-fit assembly without keys. The outer diameter has a completely processed finish, which removes the need for additional grinding and helps keep radial runout low at high speed.