Allient shrinks frameless torque motors for precision motion

The three ElectroFlux frame sizes now available from Allient, showing how far the frameless torque motor range now scales down for compact designs

(Image courtesy of Allient Inc.)

Allient Inc. has expanded its ElectroFlux Series of frameless torque motors, adding new 25 mm and 38 mm frame sizes to the range. The move is aimed at compact robotics and precision motion applications, including surgical robotic systems and collaborative robots, where integrators need high torque density inside space-constrained housings. For engineers specifying motors into tightly packaged electromechanical assemblies, the addition widens sourcing options at the smaller end of the frameless torque motor category.

Frameless torque motor specifications across the expanded range

Allient’s ElectroFlux specification overview lists frame sizes from 25 mm to 50 mm and inner diameters from 11.8 mm to 28 mm. Overall length runs from 13.7 mm to 34.9 mm, with rated torque spanning 0.032 Nm to 0.620 Nm, rated speed between 3,571 RPM and 9,476 RPM, rated current between 1.6 ADC and 11.73 ADC, and rated power from 26.8 W to 422 W, all at bus voltages of 24 V to 48 V DC. These are series-level ranges rather than the specifications of a single motor.

Why compact frameless torque motors matter for robotics integrators

Frameless torque motors ship as a rotor and stator set rather than a housed unit, with the load coupled directly to the motor and no gearbox in between. That direct coupling removes backlash and mechanical wear points, but it also means the integrator’s own housing has to hold the air gap and alignment a housed motor would otherwise provide, which is why frameless integration has traditionally demanded more engineering time than a housed alternative. Allient says the new sizes use PCB termination on the stator to reduce footprint and simplify that integration step, alongside a frameless design intended for direct embedding into a customer’s own structure. The company positions the range for surgical robotic systems, collaborative robots, and other precision or optical instruments where a housed motor would not fit the available envelope.

Robert Mastromattei, Chief Commercial Officer and Group President at Allient, said the new sizes give integrators more options for space-constrained designs where quality, size, performance and flexibility matter. Allient describes itself as serving vehicle, medical, aerospace and defence, and industrial customers through its wider motion and controls portfolio, though the ElectroFlux Series itself is positioned specifically for robotics, precision instruments, and other motion systems rather than vehicle drivetrains. Detailed CAD models and datasheets for the 25 mm and 38 mm sizes are already available from Allient’s ElectroFlux product page for engineers evaluating the range.

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