Product Description:

The 1MR242N-A071 is the dedicated rotor assembly used in the 1MB High-Speed Asynchronous Motors series from Bosch Rexroth Indramat. As a rotor for a frameless spindle motor, it forms the rotating core that couples with an external stator to deliver high peripheral speed within machine tool spindles and other precision automation axes. By providing the magnetic and mechanical structure that converts stator field energy into torque, the unit supports direct-drive configurations where compact envelopes and high rotational accuracy are required.

The rotor is produced in frame size 242, a dimensional class that establishes the outer envelope and determines compatibility with corresponding stator rings and spindle housings. Inside that frame, the laminated packet presents an inner bore of 71 mm; this diameter sets the shaft or tool-holding sleeve size that can be press-fit through the core while maintaining balanced mass distribution. Mechanical integrity is rated for surface speeds up to 16,000 min⁻¹, so the motor can sustain rapid cutting or grinding duties without exceeding permissible centrifugal stress. Dynamic response is influenced by a polar moment of 0.135 kg·m²; lower inertia improves acceleration and deceleration times in contouring applications. The manufacturing brand, Bosch Rexroth Indramat, applies controlled balancing procedures to minimize vibration at these speeds.

The rotor mass of 36.9 kg must be supported by matched bearings and drive couplings selected for the load generated during high-speed operation. Installation uses a step interference fit between the rotor core and the mating spindle shaft; this attachment method secures the assembly against micro-slip while allowing field replacement without adhesives. The build follows length designation N, indicating the specific stack height required to meet the rated magnetic output within the wider 1MB High-Speed Asynchronous Motors platform.