Roller Screw versus Ball Screw Actuators

Date: 10 July 2024

In the ever-evolving field of engineering, roller screw technology has become a significant force in linear electric actuator motion control. Electric actuators are essential in a wide array of applications, from industrial automation to advanced aerospace systems. Roller-screw technology, noted for its exceptional precision and power, is revolutionizing linear motion capabilities.

The core of roller-screw technology is a deceptively simple yet highly efficient mechanism. Unlike traditional ball screws, roller screws use threaded rollers instead of ball bearings. This subtle yet impactful change offers numerous benefits, making roller screw technology increasingly favored by engineers and designers aiming for top-tier performance.

 

Key Advantages of Roller Screw Actuators:

• Minimal Maintenance: Roller screw actuators require very little upkeep. Without ball bearings to replace or lose, re-greasing, which takes only 20 minutes, is necessary every 1-3 years. Exlar provides a 2-year product warranty.
• Durability: There is no risk of Brinelling or pitting in the recirculating ball bearing groove during repeated pressing or sealing applications with forces applied in the same position.
• Longevity: Roller screw actuators typically have a lifespan of over 10 years in most applications, making them a far more cost-effective investment compared to older technologies.
• Extended Lifespan: Roller screws last 15 times longer than equivalent ball screws in the X grade and 5 times longer in the M grade. The Budget K series offers 2-3 times the travel life.
• Compact Design: Roller screw actuators are generally more compact than ball screws.
• Lower Inertia: Roller screws have lower inertia than ball screws, allowing similar results to be achieved with smaller motors. They can provide higher acceleration/deceleration rates up to 25m/s² with a cycle rate up to 10Hz.
• Fully Integrated Solutions: Roller screw actuators can be part of a fully integrated system. Unlike ball screws that usually require an external motor, drive, and coupling, the GSX &GTX ranges are fully integrated, and the Tritex II includes the servo drive and positioner.
• Robustness: Roller screw actuators are more robust and can withstand greater shock loads

Additional benefits:

• Noise Reduction: Roller screw actuators produce less noise than their ball screw counterparts, reducing noise pollution and enhancing health and safety. They also save energy due to higher mechanical efficiency.
• Customization Options: Roller screw actuators offer extensive customization options not available with ball screws, such as front protective bellows, integrated load cells, grease zerks/nipples, various coating options, custom travel lengths, limit switches, preloaded followers for zero backlash, special greases (food grade/low temperature), integrated planetary gearboxes, and custom pulley ratios.
• Zero Backlash: Preloaded angular contact thrust bearings with zero backlash are shrunk in, not glued as with some ball screw actuators.
• Faster Cycle Rates: Roller screw actuators can achieve faster cycle rates than ball screws, up to 1.5m/s.
• Motor Adaptability: They can adapt to any motor shape or design within the I series or FT series actuators, with provided compression drive coupling or high capacity bellows coupling.The GSX & GTX are integrated.
• High Force Capability: Capable of handling forces up to 450kN.
• Extended Travel Lengths: Available with travel lengths up to 3m.
• Mounting Flexibility: Offer a wide range of mounting options, including trunnion, side mount, front flange, rear clevis, and custom mounting/client-specific front flange dimensions.
• Ancillary Options: Additional options include clevises and rod ends.

 As you can see: enough reasons to choose for roller screw technology. Drop me a line if you want to know more!

 

 

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