Consider these Design Essentials for Servo Hydraulic Actuators

Actuators with no seals and hydrostatic self-centering rod bearings have almost no friction, infinite life, high side load capability and no limitation on cyclic amplitude of movement and are well suited for precise control and low amplitude high frequency operation. However they suffer from two draw backs. Firstly they are expensive and secondly they have high internal piston leakage and high rod leakage. Techniques are available to prevent external leakage but the unavoidable internal leakage reduces positioning accuracy and energy efficiency.

Hylec Controls provides European actuators with design features such as:

  • long life actuators with low friction seals, independent of load, and suitable for low amplitude high frequency operation is now possible
  • much cheaper than a hydrostatic bearing actuator without the leakage problems
  • low friction, two-part seal, one part being carbon fibre reinforced plastic and the sealing part being a special low friction, high modulus plastic has overcome most of the limitations of former seals
  • the CFRP component and the special plastic stabilises the seal geometry, giving a previously unachievable, narrow contact surface between seal and rod or barrel. This prevents the energised back up O ring from increasing the seal contact pressure, which increases friction and wear to seal, rod or barrel
  • the weight of the piston assembly, and also of the barrel, has been greatly reduced by the use of carbon fibre reinforced plastic for these components. This reduces the effect of oil compressibility and allows for higher frequency operation. This is required for high frequency multi axis operations

It is now possible for small testing laboratories to achieve the same testing accuracy and repeatability as achieved by large laboratories using Hylec’s Servo Hydraulic Actuators. To enquire, simply email

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