R + W America’s Torque Limiters Allow Output Plate to Spin Freely

February 28, 2007—At torque overload, the balls in torque denent load limiters overcome the spring load, and roll out of their detents, allowing the output plate to spin freely over an integral bearing.

The output plate is normally either a piloted flange or a flexible coupling for connecting to (and disconnecting from) another shaft.

While suited to applications where release of the torque limiter takes place in emergency cases, occurring occasionally, they can not be disengaged repeatedly as a part of a process, due to wear of the detent plate which takes place after roughly 1,000 revolutions in its overloaded condition.

Utilizing the same principle which has been used in air ratchets in the automotive and other industries for decades, the ESL nests the ball bearings between an additional set of ball bearings, rather than into detents in a hardened steel plate. The ball bearings in the ESL roll over each other, reducing impact, and evenly distributing remaining stress around the surfaces while they spin. This significantly increases the number of overload releases the torque limiter can withstand, making it unique in the industry.

Currently the ESL is available in the form of an elastomer insert coupling, which is a low cost but robust and backlash free form of flexible coupling. They are however designed for specific OEM applications and there is a certain degree of flexibility in design when manufactured in volume. Currently torque overload values from 0.1-1,100 Nm (0.885-9735 in-lbs) and shaft bore diameters of 3-70 mm (1/8-2.75") are available.

R + W America


R+W America
Over the past 25+ years R+W has developed into a world leader in precision shaft couplings for torsional rigidity, vibration damping, and overload protection. Whether for micro motors or 10 megawatt drives, R+W couplings are customizable for most applications, while many standard models ship from stock. Configurable CAD models are available in a large number of file formats at www.rw-america.com ...Read more Or visit www.rw-america.com