The study focuses on the dynamic model of the three-linear spool flow regulator for various solutions of the spool geometry, and for two variants of mathematical description of hydraulic damping devices. The paper describes the process of small deflection linearization of the obtained mathematical models. As a result of Laplace transformation of the mathematical models, we obtained a block diagram of the spool flow regulator operation. By using Nyquist criterion, we analyzed the spool flow regulator stability. As a result, we draw conclusions on the spool flow regulator stability, and on the various types of damping devices affecting it

Рассмотрена динамическая модель работы трехлинейного золотникового регулятора расхода для различных решений геометрии золотника, а также для двух вариантов математического описания демпфирующих гидравлических устройств. Описан процесс линеаризации полученных математических моделей методом малых отклонений. Приведена структурная схема функционирования золотникового регулятора расхода, полученная в результате преобразований математических моделей по Лапласу. Проведен анализ устойчивости золотникового регулятора расхода с использованием критерия Найквиста. Сделаны выводы об устойчивости золотникового регулятора расхода, а также о влиянии на нее демпфирующих устройств различных типов

Three-linear spool-type flow regulators (hereinafter – SFR) are widely used in throttle controlled hydraulic drives to limit the volumetric flow rate supplied to the actuators in a wide load range. Depending on the hydraulic drive intended use and the SFR loading conditions, different stability and response time requirements may be specified for SFR. In most cases, if SFR is used in hoisting machine hydraulic drives, no special requirements to the response time are specified, however, the regulator operation stability must be ensured in this case.
The SFR in question is applied in a highcapacity hydraulic drive not requiring fast response time. During operation of the drive with the installed SFR, in some cases abnormal noise was observed, caused by oscillations of the SFR movable elements. The acoustic noise level and pressure fluctuations observed in this case enable speaking of resonance phenomena in the hydraulic system and SFR. Unstable operation of SFR can be due to the resonance phenomena resulting from:
erroneously selected geometry and physical characteristics of the SFR elements (spring rigidity, throttle orifice closure conditions in the spool and sleeve, hydraulic damping, etc.);
fluctuations of volumetric flow rate and discharge line pressure caused by pump operation;
load fluctuations on the hydraulic drive actuator;
action on the actuator – spool valve – of internal perturbing forces (flow turbulence, cavitation, conditions of friction in the spool and sleeve, etc.).
This article provides the results of the work developing study [

The authors declare that there are no conflicts of interest present.