Model of the Floating Bearing Bushing Movement in an External Gear Pump and the Relation to Its Parameterization

Abstract

This article presents the modeling, simulation and experimental validation of the movement of the floating bearing bushing in an external gear pump. As a starting point, a complete pump parameterization was carried out through standard tests, and these parameters were used in a first bond graph model in order to simulate the gear pump behavior. This model was experimentally validated under working conditions in field tests. Then, a sophisticated bond graph model of the movement of the floating bushing was developed from the equations that define its lubrication. Finally, as a result, both models were merged by integrating the dynamics of the floating bushing bearing with the variation of the characteristic parameters (loss coefficients). Finally, the final model was experimentally validated both in laboratory and field tests by assembling the pump in a drilling machine to drive the auxiliary movements. The novelty of this article is the conception and construction of a simple and experimentally validated tool for the study of a gear pump, which relates its macroscopic behavior as a black box (defined by the loss coefficients) to the internal changes of the unit (defined by its internal lubrication).

Motion Modelling of the Floating Bushing in an External Gear Pump Using Dimensional Analysis

“…In addition, there are the shaft forces supported by the journal bearings inserted in the bushing, which are not the same for the driver shaft F e and the driven shaft F e . Taking into account that it is often not necessary to consider any motion other than the tilting with respect to the y-axis (α) and the longitudinal movement with respect to the z-axis (h0m), the final kinematics to be studied are therefore shown in Figure 5b, the sum of a linear movement and a tilting, corresponding to those observed experimentally in the laboratory (described in Torrent et al [3]). In fact, this simplification corresponds to most of the research on the subject.…”

“…It can also be used to understand the motion of FBB in long real cycles, and hence, the fact that the simulation time would be fast is a great advantage to make it easily usable. For these reasons, the technique used to build the model is Bond Graph diagrams [2], which allow for the integration of the FBB model presented in this article within a pump model, creating a macro model, as was used in the work of Torrent et al [3].…”

“…Based on the expertise of our laboratory, laser transducers are used to measure hydrodynamic film clearances by inserting small rods into the shaft and bearing bushing. This method, developed by Gutés [10] and Castilla et al [11] to realise the journal bearing clearances, has been adapted to measure the lateral gap between the FBB and the gears, described in Torrent's Ph.D. Thesis [12] and in the article by Torrent et al [3].…”

“…With respect to the previously published article of Torrent et al [3], two notable novelties are introduced in this work. The first is to deepen into the dimensional analysis to consider the lubrication between gears and FBB as the sum of the effects of a sliding and a thrust bearing.…”

Modeling the Meshing Procedure of the External Gear Fuel Pump Using a CFD Tool

“…Several approaches exist today [3] for external gear pump modeling but the most commonly used are computational fluid dynamics (CFD) and lumped parameters models. Results of simulation using modeling with lumped parameters for external gear pump have been shown in article [4][5][6][7][8][9]. This approach uses the division of pump volume for control volumes in which fluid properties are assumed uniform and dependent on time only.…”