The previous researches show that it is possible to replace several parts of gear pumps to polymeric ones. This substitution leads to cost and noise reduction of the pump unit. Therefore, the series of experiments on test bench SVNSH-08 with the use of acoustic camera Norsonic Nor848 for the analysis of acoustic characteristics was carry-out. Measuring system -portable 12-channel signals analyzer LMS SCADAS Mobile (SCM05) was used. Conducted experiment shows that acoustic characteristics of the pump unit depend on different material drive and driven rotor. Experimental result indicates that the proposed measures for replacing metal pinion shafts to polymeric reduce pump unit noise on the test modes.

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Progress in the field of microelectronics and micromechanics has created new opportunities for the development of fluid power microsystems and microhydraulics. Miniaturization of hydraulic elements allows replacing the classical hydraulics with microhydraulics, where due to size or weight the former cannot be applied. Gear pumps are common use due to their reliability, resistance to working medium impurities, high efficiency, small size in comparison with other pumps and simple and compact design. Therefore micropumps often associate with a gear pump type. A micropump entails microbearings production. This requirement leads to cost increasing due to requirements to high accuracy of manufacturing. The paper focuses on a method for micropumps production without bearings. The idea based on application of materials with satisfactory friction coefficient in pairs. Friction pairs analysis made from different polymer and composite materials was carried out. As a result a gear micropump was designed and produced.

The paper describes measures to reduce the level of acoustic emittion of a low-gear external gear pump. On the basis of the experiment on a bench installation, the acoustic efficiency using rotors were made from PEEK material in the design of a gear pump was evaluated when shaft speed was of 1000 ... 2500 rpm and a discharge pressure of 3 ... 12 bar. For comparison, the article presents the acoustic efficiency by the relative difference of the acoustic emittion of the pump with configuration of the «steel-steel» and «steel-PEEK» rotors. It also provides an overview of methods for reducing mechanical noise in gears, damping of modern structural polymeric materials based on polyamide, polyacetal, polyphenylenesulfide and polyetheretherketone in comparison with traditional engineering materials - steel, aluminum, gray cast iron is estimated. Recommendations for using of polymeric materials in the design of the pump are proposed.

External gear pumps are among the most popular fluid power positive displacement pumps; however, they often suffer from excessive flow pulsation transmitted to the downstream circuit. To meet the increasing demand of quiet operation for modern fluid power systems, it is necessary to give a physically sound method of analyzing the operation of a volumetric pump. The analysis of the basic approach used by the majority of researchers for calculating the flow rate of a gear pump by E.M. Yudin is presented. The article presents a new method for analyzing the operation of volumetric pumps. The method is suitable for the pumps whose dynamic characteristics should be considered according to the model of an equivalent source of flow fluctuations by V.P. Shorin. The method is based on wave theory, the method of hydrodynamic analogies and the impedance method, where the pump is considered according to the model in lumped parameters. The method consists in determining the pressure pulsations at the pump output in bench systems with known dynamic characteristics and recalculating the pump flow rate in pulsations. Computational dynamic models of bench systems in lumped parameters are proposed for subsequent use in dynamic tests of pumps in the form of equivalent sources of fluid flow fluctuations. We give recommendations for the formation of test bench systems with a throttle, a cavity and a pipeline at the pump output. Using the example of an external gear pump with a working volume of 14 cm3/rev, the implementation of the proposed method is considered. The pump’s own pulsation characteristic of the flow rate in a bench system with an “infinitely long” pipeline along two harmonic components of the spectrum is determined, and a test of the method based on the method of determining the instantaneous flow rate by R.N. Starobinskiy is proposed. It is shown that, according to the proposed method and the method of R.N. Starobinskiy, the divergence of the amplitudes of flow pulsations does not exceed (5–10)%. The high degree of coincidence of the results confirms that the external gear pump in question should be considered according to the equivalent source of flow fluctuations model.