Product Description:

The 1MR375D-A170 rotor is built by Bosch Rexroth Indramat for the 1MB High-Speed Asynchronous Motors series. As the rotating core of a frameless spindle motor, it transmits electromagnetic torque to the machine-tool spindle without the weight of an external housing. Within high-speed machining centers and grinding heads, this type of rotor lets integrators mount the stator directly in the machine frame, shortening the power path and improving dynamic accuracy in automated cutting, drilling, and finishing stations. This arrangement also keeps the spindle package compact and supports fast response during speed changes.

These dimensions determine how the rotor couples to the spindle shaft. It matches a 375 frame and carries an internal bore of 170 mm for interference assembly to the customer’s shaft. Outside, the laminated stack measures 273.7 mm in diameter, setting the air gap with the stator. A step interference zone that runs 422 mm along the shaft secures the rotor during high-speed rotation, while the full laminated and shaft assembly spans 530 mm. M10 balancing-ring threads at each end accept correction screws, and M6 pressure-oil ports support hydraulic extraction. The mating spindle follows tolerance class s6, and the D length code indicates the axial size within the series.

Dynamic parameters guide drive selection and safety calculations. The steel and copper stack weighs 132 kg, and its polar mass distribution yields a moment of inertia of 1.73 kg·m²; these values affect the acceleration torque required from the inverter. Spindle design must also reserve at least 537 mm of shaft length so the interference section seats fully without compromising tool holders. With 3 pole pairs, the rotor reaches synchronous surface speeds at electrical frequencies common to high-speed drives, which helps limit slip losses. The step-fit construction limits micromovement under thermal growth, and the balanced M10 interface simplifies on-site trim balancing after mounting.