Packed with power. Mini but mighty. Compact housing. What do these phrases have in common? Each hints at a design optimizing torque density. At its core, torque density is all about getting the most power from the least amount of space. For applications where cubic inches are at a premium, consider these power-packed products and expert tips.
High torque servomotor
The DST servomotor series offers higher torque density in a 30% smaller package than previous designs; handles speeds up to 4,500 rpm and works as a direct drive in place of small gears.
Hybrid stepper motor
H3 stepmotors use aluminum housing for superior heat dissipation to create high torque. Stator-enhanced magnets deliver up to 40% more torque in the same footprint as other motors, while oversized bearings handle larger-than-normal side and radial loads.
Size 8 hybrid linear actuators, now with encoder feedback, occupy a space of just 21 mm square. With thrusts up to 10 lb, these motors are well suited for applications requiring precise positioning and rapid motion.
Haydon Switch & Instrument Inc.
Servo insert couplings
Torque-dense Servomax couplings feature a precision molded elastomer element press fit between two precision machined coupling halves, resulting in zero backlash and guaranteed concentricity.
The TPM+ incorporates a high-precision gearhead, high-pole motor, and feedback in a compact package. The highly integrated actuator is 50% smaller than standard motor-gearbox combinations in terms of size as well as mass.
Wittenstein Motion Control
DBO ✓ list
Think more power in less space
Consider smaller, stronger motors and gears
In motors, increase content of active materials (iron, copper, permanent magnets) to increase torque
Likewise, decrease content of inactive materials (air, plastic, insulation)
Heat is the limiting factor in electric motors with regard to torque density
Remember that magnets can only take so much heat; then they weaken, reducing motor torque
Key to torque density is current density
Think about coil winding design; traditional design limits use of copper inside slots on motor stators
Less copper means less current, less magnetic flux, and less torque
High slot fills mean maximum current per unit of motor circumference, creating maximum torque density
Consider “cut-core” stator technology with each tooth individually wound prior to motor assembly
Keep windings cool to improve torque density
Proper motor cooling (correct heat sinking and unimpeded air flow) is vital to torque density
Attach motor to heat sink; paint motor black; lower ambient temperature
Apples to apples: When comparing motor torque, look at continuous duty ratings and product lifespan
Consider planetary and right angle (worm, bevel, hypoid) gear sets for maximum torque density