Product Description:

The 1MR310B-A112 rotor is manufactured by Bosch Rexroth Indramat for the 1MB High-Speed Asynchronous Motors series. Designed as the rotating core of a frameless spindle assembly, it is installed inside a machine-tool spindle where it works with a surrounding stator to generate the torque that drives cutting tools. In industrial automation, the rotor translates the electromagnetic field produced by the inverter-fed stator into precise, high-speed mechanical motion for milling, drilling, and grinding operations. This frameless arrangement allows the motor to become part of the spindle assembly instead of a separate, shaft-coupled unit.

Dimensionally, the rotor belongs to Frame Size 310, so its outside diameter aligns with matching 1MB stators and helps preserve concentric running accuracy. The bore measures 112 mm, allowing it to fit over a standard spindle shaft while maintaining air-gap uniformity. Safe continuous operation is permitted up to 8000 rpm, a speed limit that balances productivity with the centrifugal stress limits of the laminated core. Magnetic coupling is set by 3 pole pairs, which determines the electrical frequency needed for the commanded mechanical speed. Despite its diameter, the component weighs 63.3 kg, which is useful when calculating bearing loads, dynamic balance, and handling requirements.

Dynamic response is influenced by a moment of inertia of 0.477 kg·m², which affects acceleration time and the energy absorbed during rapid deceleration. Shaft engagement is secured through a step interference fit that helps maintain clamping pressure as temperatures vary. The stack height corresponds to Motor Length Code B, providing a reference for torque potential when the correct stator is paired with the rotor. The unit is a Rotor for 1MB Frameless Spindle Motor, and it must be matched with compatible bearings, lubrication, and cooling elements for proper operation. Because the rotor is only one part of the spindle drive, the surrounding assembly supplies the support structure and thermal management it requires.