Kinematics Integrated Clutch Design for Slew Drives

KMI is known for its rotary actuators that drive everything from man lifts to solar trackers. This post will share how a clutch system can address extreme events without over-specifying the entire equipment system.

Slew drives provide an efficient means to deliver high torque at a minimum size, weight, and cost. Most application designers exploit those efficiencies, specifying the minimum drive design specifications to meet performance requirements, as they would for other components to the complete system. Unfortunately, in the real world, all applications suffer from “extreme events.” These are operating situations clearly outside the “normal” conditions, and may only occur 1% or less of the time.  When these extreme forces need to be accounted for in the system design, efficiencies can be lost.

To address these corner cases, KMI’s design labs successfully integrated plate clutch technology to its slew drive to efficiently manage extreme events without needing to over-specify the entire system. KMI’s clutch system is a friction clutch design intended to slip when the torque exceeds the “normal” operating range of the equipment. By managing extreme forces with a clutch, the slew drive and adjacent system components can be designed to perform for the known, versus anomaly, operating conditions. This allows designers to stick with a far more efficient design solution.

Integrating a clutch system design into a drive train requires an understanding of the application requirements. It is as important not to slip when torque is needed as it is to slip when torque needs to be relieved. KMI engineering can support the development of these design parameters. As examples, the following ranges can be defined when integrating a clutch:

  • Normal Operating Torque ( can be <85% of the performance limit)
  • Maximum Operating Torque (can be 85 – 100% of the performance limit)
  • Slip threshold ( can be >110% of the performance limit)
  • Slip Stop where clutch re-engages (can be approximately 90% of the performance limit)

Industrial and environmental conditions can apply extreme torque in seconds (think, a sudden gust of wind on a solar array). The ability to efficiently manage these impulse forces within the system capacity, before damage occurs, can deliver significant value in terms of equipment cost, maintenance, uptime, and safety. Maximum system uptime and minimal maintenance and repair are KMI’s client’s expectations. Downtime can significantly erode service delivery, damage reputation, and even deteriorate financial performance. This is made all the more challenging when products are used in hostile environments introducing unexpected forces. Yet these are challenges that KMI has and continues to thrive on taking on.

In our next related post, we’ll share some application examples.