Product Description:

The 1MR310B-A125 is a rotor component engineered by Bosch Rexroth Indramat for the 1MB High-Speed Asynchronous Motors series. As a dedicated rotating element for frameless spindle assemblies, it couples to the stator to convert drive current into mechanical rotation for CNC machining centers, grinding spindles, and other high-speed automation tasks that require accurate rotation. The component’s dimensional code and mechanical interface allow it to fit directly into the spindle housing while sustaining the thermal and dynamic loads common in continuous industrial duty at elevated spindle speeds.

A frame diameter of 310 establishes the rotor’s outside size and assures alignment with the matching stator laminations. The internal shaft interface is a 125 mm bore, providing clearance for a rigid clamping system and consistent concentricity. During operation, the rotating assembly can reach a maximum mechanical speed of 8000 rpm; this ceiling marks the allowable frequency range for the inverter and the safe limiting speed for the bearings. The electromagnetic layout uses 3 pole pairs, so synchronous frequency relationships between current and torque are maintained without excessive harmonic loss. A rotational inertia of 0.477 kg·m² characterizes the energy stored in the spinning mass and indicates the torque the drive must supply for rapid acceleration or deceleration.

Several mechanical features support stable rotor operation at high spindle speeds and under repeated acceleration. A total rotor mass of 65 kg supplies the stiffness required for shaft stability while remaining low enough for manageable spindle acceleration. Vibration is reduced through a balancing method that relies on threaded pins, so imbalance can be corrected without removing the rotor from the housing. Lubrication lines connect to 2 pressure oil ports, allowing continuous hydrostatic support of the front and rear bearings during high-speed duty cycles. The core is machined with a step interference fit; this press-fit profile locks the rotor to the shaft collar and helps prevent micro-slip during thermal expansion.