Internal Leakages in a Water Hydraulic Pump with Gears From Plastic


  • Michał Banaś Wrocław University of Science and Technology, Wroclaw, Poland



Composites;, PEEK;, PPS GF40, Clearances, Tap water, Internal flow


Plastics are used more and more in hydraulic systems. The chemical properties of the plastics favour the use of working fluids alternative to mineral oil, e.g. water. The conditions in the manufacturing process, e.g. injection moulding, limit the achievement of high working pressures in the hydraulic elements. Internal leakage reduces the efficiency of the hydraulic pump with plastic gears. The article presents the results of internal leakage tests of a water-supplied hydraulic pump. Gears made of various materials (PPS+GF40 and PEEK) have been used in the research, made by two methods: injection moulding and machining. A simplified mathematical model of the dependence of leakages on pressure and rotational speed has been developed. The influence of the materials and manufacturing methods used on the pump operation is discussed.


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Author Biography

Michał Banaś, Wrocław University of Science and Technology, Wroclaw, Poland

Michał Banaś received the master’s degree in mechanical design from Wrocław University of Science and Technology in 2000, and the philosophy of doctorate degree in Machine Design from WUST in 2005, respectively. He is currently working at the Department of Mechanical Engineering, WUST. His research areas include machine design, mechatronics, hydraulic machines, and plastics. He has been serving as a reviewer for many highly-respected journals. OrcidID 0000-0003-3433-1249.


Stryczek, J.; Banaś, M.; Krawczyk, J.; Marciniak, L.; Stryczek, P. The Fluid Power Elements and Systems Made of Plastics. Procedia Eng. 176(204), pp. 600–609 (2017). doi:10.1016/j.proeng.2017.02.303

Krawczyk, J. Sobczyk A., Stryczek J., Walczak P.: Tests of New Methods of Manufacturing Elements for Water Hydraulics. In: Materials Research Proceedings vol. 5, pp. 200–205. (2018). doi:10.21741/9781945291814-35

Rodionov, L., Rekadze, P., and Stryczek, J. (2015). A Gear Micropump without Bearings Production. Applied Mechanics and Materials, 775, 352–356. doi:10.4028/

Biernacki, K. (2020). New construction of cycloidal gear unit made of plastics. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science. doi:10.1177/0954406220939999

Bonanno, A. (2008). Materialli polimerici applicazioni. Oleodynamica Pneumatica, Aprile, 200876, 79.

P. Antoniak, J. Stryczek, Visualization study of the flow processes and phenomena in the external gear pump, Archives of Civil and Mechanical Engineering, Volume 18, Issue 4, 2018, Pages 1103–1115, doi:10.1016/j.acme.2018.03.001

Bednarczyk, S., Jankowski, L. Krawczyk, J. (2019). The Influence of Eccentricity Changes on Power Losses in Cycloidal Gearing. Bimonthly Tribologia, 285 (3), 19–29, doi:10.5604/01.3001.0013.5430

Parker (2007), Lightraulics® Composite Hydraulic Cylinders For working pressures up to 700 bar, Catalogue HY07-1410/UK.

Plastics, Last accessed 12 Nov 2020.

MatWeb, http:// Last accessed 12 Nov 2020.

Hodges, P. (1996). Hydraulic Fluids. Elsevier Science.

Thelmul Hydraulic Fluid HFB LT 68”, Aztec Oils, 2018.

Lide D.R.: CRC Handbook of Chemistry and Physics. 85th edn. CRC Press LLC, Florida, USA (2004).

Banaś M. (2021) Volumetric Efficiency of a Hydraulic Pump with Plastic Gears Working with Tap Water. In: Stryczek J., Warzyńska U. (eds) Advances in Hydraulic and Pneumatic Drives and Control 2020. NSHP 2020. Lecture Notes in Mechanical Engineering. Springer, Cham. doi:10.1007/978-3-030-59509-8_32

Zhou, H., and Song, W. (2011). Optimization of Floating Plate of Water Hydraulic Internal Gear Pump. Proceedings of the 8th JFPS International Symposium on Fluid Power, OKINAWA 2011 Oct. 25–28, (2011)

Śliwiński, P. (2017). The Influence of Water and Mineral Oil On Volumetric Losses in a Hydraulic Motor, Polish Maritime Research, 24(s1), 213–223. doi:10.1515/pomr-2017-0041

Ivantysyn, J. and Ivantysynova, M.: Hydrostatic Pumps and Motors: Principles, Design, Performance, Modelling, Analysis, Control and Testing. Tech Books International (2003).

Casoli, P., Vacca, A., Franzoni, G. (2005). A Numerical Model for the Simulation of External Gear Pumps. Proceedings of the JFPS International Symposium on Fluid Power. 2005. doi:10.5739/isfp.2005.705

Rundo, M. (2017). Models for Flow Rate Simulation in Gear Pumps: A Review. Energies, 10(9), 1261. doi:10.3390/en10091261

Krawczyk, J, Stryczek, J. (2014), Construction and Experimental Research on Plastic Cycloidal Gears Used in Gerotor Pumps. Proceedings of the 8th FPNI Ph.D Symposium on Fluid Power. 8th FPNI Ph.D Symposium on Fluid Power. Lappeenranta, Finland. June 11–13, 2014. V001T01A006. ASME. doi:10.1115/FPNI2014-7827