Innovation in Motion

Kyntronics SMART Electro-Hydraulic Linear Actuators (SHA) are a robust “electric” alternative to screw-type actuators. The features and benefits of these two actuation technologies are compared below.

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Ball Screw / Roller Screw Electro-Mechanical Actuators (EMA)

Ball Screw and Roller Screw actuators (EMAs) are a commonly-used linear motion solution. These systems are deployed where precision control is required and often as a replacement for hydraulic cylinders in some higher force applications.

compare emaScrew-Type actuators are susceptible to damage from shock loads and premature wear causing unplanned downtime and reliability issues.

Screw-Type EMA Challenges

  • Gears, roller and ball screws and other mechanical components wear out from metal-to-metal contact from repetitive concentrated loads.
  • Shock loads and Side loading can cause significant damage and premature failure.
  • EMAs require regular lubrication and have a finite life (see L10 chart below).
  • EMAs require expensive load cells for accurate force control.
  • EMAs require a brake to hold position, can be back-driven and have backlash.
  • Are large & very costly at higher loads (>5,000lbf).
  • Have limited stroke length (24”) without incurring expensive premiums.

SMART Electro-Hydraulic Actuator (SHA)

The SHA is an “electric linear actuator” that looks similar to a screw-type actuator but rather than using gears, drive screws and driven nuts, the all-in-one SHA uses an integral hydraulic cylinder with minimal amount of fluid and no hoses or leak points.

The SHA combines the Best Features of Screw-Type EMAs and Hydraulic Actuators while Eliminating their Shortcomings

compare ema

Actuator Reliability Comparison

Kyntronics SMART Electro-Hydraulic Actuator (SHA) vs Electro-Mechanical Ball Screw / Roller Screw Actuator (EMA)

 Ball Screw Actuator
 Roller Screw Actuator
 Kyntronics SMART Electro-Hydraulic Actuator (SHA)

Electro-Mechanical Actuator (EMA)

  • EMA life span is load dependent. Improving EMA life requires larger and more expensive size screws
  • EMA metal-to-metal wear further decreases reliability and requires regular lubrication
  • EMAs are highly susceptible to damage from shock loads and side-loading

Kyntronics SMART Electro-Hydraulic Actuator (SHA)

  • SHA is rated at 50,000,000 inches of travel (before a simple rod seal change) regardless of load
  • No metal-to-metal contact leads to increased reliability (load independent)
  • The SHA provides 10X-100X better reliability compared with Ball Screw / Roller Screw Actuators


Cost Comparison at Different Force Ratings

Kyntronics SMART Electro-Hydraulic Actuator (SHA) vs Electro-Mechanical Roller Screw Actuator (EMA)

Cost comparisons

 Roller Screw EMA
Kyntronics All-in-One SMART Electro-Hydraulic Actuator

Cost Assumptions

  • Includes Actuator, Servo Motor, Servo Drive
  • 24" Stoke Length, add 15% Premium to Roller Screw if longer
  • Standard Configuration, Standard L10 Roller Screw Life
  • Cost Amounts are Approximate Distributor Net Cost


The SHA is available in many flexible configurations unlike screw-type EMAs

Parallel StandardParallel StandardParallel with Spacer BlockParallel with Spacer Block90 Centered90° CenteredParallel InvertedParallel InvertedInlineInlineParallel 90 Behind Power Unit90° Behind Power Unit


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To discuss your application with an Engineer and learn how the SMART Electro-Hydraulic Actuator (SHA) can help to eliminate hydraulics from your business, contact Kyntronics.