fabbrica_ad_elevate_prestazioniTitle: Surface Nano-structured Coating for Improved Performance of Axial Piston Pumps

Area: 1 – High-performance Factories

Call topic: 1.2 – Innovative technologies for the carrying-out of components characterized by advanced functional features

Coordinating Institute: IMAMOTER – Institute for Agricultural and Earthmoving Machines (Ferrara)

Partnership:

  • IENI – Institute for Energetics and Interphases (Padova)
  • ISTEC ‐ Institute of Science and Technology for Ceramics (Faenza)

Industrial Interest Group: 

  • Fiori Group SpA (Finale Emilia(BO))
  • HP Hydraulic SrL (pieve di Cento (BO))

Abstract: The project starts from the consideration that most of the power losses in a hydraulic pump come from the friction between parts in relative motion. The need to provide, especially at low rotational speed, hydrodynamic lift, causes power losses, in terms of volumetric and mechanical efficiency, due to the contrasting need to increase leakage to provide lubrication and to keep a minimum clearance in meatus to limit the volumetric losses. The potential for application of special surface treatments have been exploited in pioneering works in the past, 6 trying different surface finishing or adding ceramic or heterogeneous metallic layers. The potential of structured coatings at nanoscale, with super‐hydrophobic and oleophobic characteristics, has never been exploited. The project aims at investigating the potential of surface nano‐coating of the swash‐plate surface, in order to improve the overall efficiency map of the component through a significant reduction in fluid friction losses.

The topic addressed by the project SNAPP has been selected by NSERC-Automotive Partnership Canada in order to be included in the “Concurrent Call on Automotive Manufacturing R&D”, which was launched within the bilateral cooperation agreement signed by the Natural Sciences and Engineering Research Council of Canada (NSERC) and the National Research Council of Italy (CNR) (Memorandum of Understanding for Scholarly and Scientific Cooperation). This agreement aims at promoting cooperation between Italian and Canadian researchers through the financing of joint cooperation projects.

Ideas and solutions:

snappThe project starts from the consideration that most of the power losses in a hydraulic pump come from the friction between parts in relative motion. The need to provide, especially at low rotational speed, hydrodynamic lift, causes power losses, in terms of volumetric and mechanical efficiency, due to the contrasting need to increase leakage to provide lubrication and to keep a minimum clearance in meatus (squeeze film bearing) to limit the volumetric losses.

 

snapp-3snapp-1The potential for application of special surface treatments have been exploited in pioneering works in the past, trying different surface finishing or adding ceramic or heterogeneous metallic layers. The potential of structured coatings at nanoscale, with super-hydrophobic and oleophobic characteristics, has never been exploited. The project aims at investigating the potential of surface nano-coating of the swash-plate surface, providing poor wettability against polar and non-polar fluids so facing the slippers and the timing port, in order to improve the overall efficiency map of the component through a significant reduction in fluid friction losses.

 

Follow up:

snapp-4We have tested a simple methodology for the coating of samples with different morphology and size and consequentially being easily transferrable to industrial scale, the dip coating process.

The treatment radically modifies the wettability of the sample towards the lubricant oil: from an extremely oleophilic behavior (CA equal to 17°, denoting affinity of the skid surface for the lubricant) to a quite strong oleophobicity (CA equal to 124°, denoting repellence of the skid surface towards the lubricant).

We have developed a dedicated test bench to evaluate the performance of the coated samples

The performed test have shown the possibility of nano-coated surfaces to reduce the absorbed torque of about 20-30% compared to the standard components.

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