Gear pumps represent the majority of the fixed displacement machines used for flow generation in fluid power systems. In this context, the paper presents a review of the different methodologies used in the last years for the simulation of the flow rates generated by gerotor, external gear and crescent pumps. As far as the lumped parameter models are concerned, different ways of selecting the control volumes into which the pump is split are analyzed and the main governing equations are presented. The principles and the applications of distributed models from 1D to 3D are reported. A specific section is dedicated to the methods for the evaluation of the necessary geometric quantities: analytic, numerical and Computer-Aided Design (CAD)-based. The more recent studies taking into account the influence on leakages of the interactions between the fluid and the mechanical parts are explained. Finally the models for the simulation of the fluid aeration are described. The review brings to evidence the increasing effort for improving the simulation models used for the design and the optimization of the gear machines.

Models for Flow Rate Simulation in Gear Pumps: A Review

Dynamic modeling and contact analysis of a cycloid-pin gear mechanism with a turning arm cylindrical roller bearing

Cycloidal speed reducers are composed primarily of an eccentric shaft, output parts, and a set comprising a cycloidal gear and pinwheel with pins or a cycloidal gear and cycloid internal gear. This paper investigates the contact and collision conditions of these components, as well as their stress variations during the transmission process. To do so, a system dynamics analysis model of a cycloidal speed reducer is constructed, together with dynamics analysis models for two design types: A traditional pinwheel design and a nonpinwheel design (i.e., a design in which a cycloid internal gear replaces the pinwheel). Based on the theory of gearing, a mathematical model of the pinwheel with pins, cycloidal gear, and cycloid internal gear is then built from which the component geometry can be derived. These dynamics analysis models, constructed concurrently, are used to investigate the components' movements and stress variations, and determine the differences between the transmission mechanisms. The results indicate that the nonpinwheel design effectively reduces vibration, stress value, and stress fluctuation, thereby enhancing performance. An additional torsion test further suggests that the nonpinwheel design's output rate is superior to that of the traditional pinwheel design.

Dynamics Analysis of Cycloidal Speed Reducers With Pinwheel and Nonpinwheel Designs

Kinematic error analysis and tolerance allocation of cycloidal gear reducers

Dynamic modelling and contact analysis of bearing-cycloid-pinwheel transmission mechanisms used in joint rotate vector reducers

This paper explains development of the general mathematical model of trochoidal gearing that can be applied for gerotor pumps and cyclo reducers. The model analyzes geometry and physics of the gearing pair in trochoidal pump where the outer gear has one tooth more than the inner gear. The inner gear profile is described by peritrochoid equidistance and the outer gear profile by circular arc. Mathematical model of gearing with clearances is based on the principle of an ideal profile development. Minimum clearance height between teeth profiles in relation to instantaneous gear ratio is determined. The influence of gear profile geometrical parameters on gearing process, clearance height change, and pulsation of drive moment is analyzed and presented in numerical examples. Obtained results can be used for the design of the trochoidal gearing where accurate and silent operation is required. [DOI: 10.1115/1.4005621]

Modeling of the Meshing of Trochoidal Profiles With Clearances

This article presents the analyses of the forces and moments between gears in contact with a gerotor pump. The objective was to reach a more accurate solution for the problems related to load distr...

Analysis of Forces and Moments in Gerotor Pumps

The paper presents the methodology for multicriteria decision analysis based on negative-positive-neutral (NPN) logic, which is an extension of both crisp and fuzzy logic. As the basic modeling framework we use fuzzy cognitive maps (FCM) which are a set of meaningful concepts, connected to form a network, with fuzzy weighted links measuring the strength and direction of effect of cause concept over target concept. Introducing NPN logic to FCM modeling framework provides the possibility to measure, the so-called, side effect of each decision-making path. This information additionally describes under what mutual conditions between concepts FCM settles down in equilibrium. An illustrative example from the real industrial environment related to metal cutting process planning parameters analysis demonstrates the potential of the methodology.

https://www.researchgate.net/profile/Miodrag_Manic/publication/267845566_Conceptual_Framework_for_NPN_Logic_Based_Decision_Analysis/links/54c63b3f0cf219bbe4f71efb.pdf

Nenad Mirić

Papers

Modeling of the Meshing of Trochoidal Profiles With Clearances

Analysis of Forces and Moments in Gerotor Pumps

Conceptual Framework for NPN Logic Based Decision Analysis