Lightweight hydraulic cylinders made of H-CFRP
Herbert Hänchen GmbH in Ostfildern, near Stuttgart, has developed a new carbon fiber reinforced plastic, known as H-CFRP.
Hänchen makes hydraulic cylinders extremely lightweight (Photo: Herbert Hänchen GmbH & Co. KG)
The plastic combines the key material properties of steel cylinders with an ultra-low weight, making hydraulic cylinders 70% lighter. Leichtbau BW, the public development agency serving companies and research groups in Baden-Wuerttemberg, awarded the company the "ThinKing" label for its innovation last year.
H-CFRP can be used on all parts with an extremely smooth surface (surface roughness 1) and tight tolerances (ISO 7). Properties like these make the material ideal for use in hydraulic cylinders. The materials significantly lower weight, compared to that of steel, also enables faster accelerations, which reduces the energy consumption of the cylinders by up to 50%. To create the H-CFRP material, Herbert Hänchen GmbH had to develop new technologies to design the component and to bind the CFRP and metal. They also had to develop a hard and wear-resistant surface, which seals in the core carbon material.
"To realize this, we did research for new computation models and a suitable production process. Then we could define the number and type of carbon fibers according to the desired density and bend strength
Klaus Wagner, department director for research and innovation at Hänchen
Klaus Wagner, department director for research and innovation at Hänchen, explains that to develop the H-CFRP material, three new technologies were required to design the component, bind the materials and treat the surface. On the one hand, the challenge was to create round parts that could withstand great forces in three dimensions.
When producing components for cylinders, the carbon fibers are selected and designed as required. The resulting hybrid materials made of metals and carbon fiber reinforced plastics (CFRP) withstand the very high stress to which they are exposed in hydraulic applications.
Lightweight rods and pipes with smooth surface and tight tolerances (Photo: Herbert Hänchen GmbH & Co. KG)
What are the properties of H-CFRP ?
> Lightweight: Compared with steel, H-CFRP means a mass reduction of up to 80% for cylinder tubes, and up to 75% for piston rods. The weight reduction is especially noticeable for long strokes.
> Non-magnetic: Carbon is a non-magnetizable material. This is relevant e.g. for cylinders with a piston rod made of H-CFRP and a magnetostrictive position transducer, resulting in a shorter installation length.
> Energy-efficient: With moved or accelerated components the energy efficiency can be improved due to the reduced weight. Depending on the application, the load capacity can be increased, or the required drive power reduced. In particular, H-CFRP piston rods make it possible to use smaller hydraulic components while maintaining the performance, and realizing a higher dynamic.
> No expansion: Carbon fibers have a very low negative coefficient of thermal expansion in longitudinal direction. This makes H-CFRP an interesting material for very precise applications.
> No corrosion: The high corrosion resistance of carbon in combination with non-corroding metals makes H-CFRP a reliable material. The use of epoxy resins for the matrix, and high-quality fiber, prevents chemical attacks caused by strong alkaline or acid substances.
> Bending-stiffness: The tenacity and stiffness of the anisotropic material H-CFRP are considerably higher in the direction of the fiber than in the perpendicular direction. Depending on the fiber direction, there are different elasticity modules, which permit higher lateral forces.
What are the application sector of H-CFRP ?
About Herbert Hänchen GmbH & Co. KG:
The family owned company was founded in 1925 by Herbert Hänchen. In 1950, the company moved to the new headquarters in Ostfildern Ruit near Stuttgart. Today, Hänchen is still family operated by the third generation and has over 200 employees. The company is specialized in the research, development and manufacture of hydraulic cylinders and customized drive systems.
» Publication Date: 08/02/2019
This project has received funding from the Bio-Based Industries Joint Undertaking under the European Union’s Horizon 2020 research and innovation programme under grant agreement Nº 745828