Overview: Kyntronics Electro-Hydraulic Actuators Comparison to Exlar Roller Screw Actuators
Kyntronics Electro-Hydraulic Actuators offer an alternative technology to Exlar's roller screw actuators. The roller screw technology was more efficient than the existing acceptable technologies at the time of its introduction. The roller screws are susceptible to shock loads, they require a brake for holding position, the actuators are not a sealed solution and they require maintenance (grease) to avoid premature failures.
The Kyntronics EHA is a self-contained Electro-Hydraulic actuator that can be configured with or without a motor / drive solution. The EHA combines the robustness of the hydraulic cylinder along with the accuracy of a servo-controlled solution.
While Exlar is struggling to meet 12-14 week lead times, Kyntronics can provide a better product, at a better price at a fraction of the lead time
The EHA has a built in “mechanical advantage” with the simple formula: [Force = Area x PSI]. Since the Area is an exponential function, as the cylinder changes 20% (2.5" to 3"), the force increases (44%). This "mechanical advantage" provides a smaller, compact package. There is no mechanical wear which provides a quiet – efficient solution. The fluid is self-contained, there is no leaking and does not allow any ingress of any liquid providing an out of the box IP65 solution.
The EHA is designed to be very modular. With a few part replacements (motor, drive, pump), one can configure a multitude of variations to meet the customer's needs. This provides Kyntronics the ability to stock key configurations ready to be assembled delivering the ability to meet very short lead times.
While Exlar is struggling to meet 12-14 week lead times, Kyntronics can provide a better product, at a better price in a fraction of the lead time. Please see below for a cross reference of Kyntonics offering to the Exlar products.
EHA vs. Roller Screw (RS) Technology Features Comparison
- The RS technology requires maintenance and may require an external lubrication unit
- The EHA requires no maintenance
Compact - Mechanical Advantage
- π r2 * psi e.g. with a 20% increase in a 2 inch diameter cylinder, the force increases 44%. This keeps the actuator compact, uses a smaller motor & drive and is more cost effective
- The RS technology requires a brake to hold position. The brake requires a continuous current to release (fail safe) adding to the overall current making the RS even more inefficient.
- The EHA does not require a brake. As soon as the actuator stops, it locks into position.
- It is well understood that a hydraulic system can handle shock loads much better than any mechanical system. The mechanics have metal to metal components which bind and are not designed for impact or shock loads. The EHA handles the shock loads with non-compressible hydraulic oil. The more of a load, the more the valves close holding position.
- The EHA is a more efficient solution converting the electrical input power compared to the output power moving a load. The hydraulic conversion of power is extremely efficient and as previously mentioned, the EHA does not require a brake eliminating the current that is required to hold the brake open during motion in an RS system.
- With all mechanical actuators, they are all capable of back-driving. With the EHA, once it stops, it locks into position and cannot be back driven from an external force.
- The EHA provides an integral force feedback with the simple addition of a pressure sensor.
- The RS would require an expensive external load cell along with extra mounting and wiring.
- With all mechanical designs, they are inherently subject to liquid intrusion eroding the life of the actuator. Some companies provide IP ratings only at stand still. The Kyntonics EHA has an inherent IP65 rating at stand still and during motion.
Exlar Roller Screw vs. Kyntronics EHA Cross Reference Chart
Article by Carl Richter, December 2016