A Solution for an Electronically-Controlled Variable Delivery External Gear Pump

2017 ◽  
Author(s):  
Srinath Tankasala ◽  
Andrea Vacca
Keyword(s):  
Cost Effective ◽  
Spur Gear ◽  
Gear Pump ◽  
Electronic Control ◽  
Pump Design ◽  
Flow Variation ◽  
Electronic Control System ◽  
Gear Pumps ◽  
Pressure Compensation ◽  
External Gear Pump

This paper describes an innovative design concept to enable electronic control of the flow delivered by external spur gear pumps. The basic principle used to obtain flow variation relies on a variable timing concept previously demonstrated by the author’s research team. This principle permits to vary the flow within a certain range, without introducing additional sources of power loss. Previous work proved the applicability of the proposed concept in a pressure compensated design of an external gear pump for high pressure applications. This concept took advantage of the pressure differential acting on the “slider”, which is an internal element performing the flow regulation. In this paper, a solution that permits to achieve balance of the pressure forces acting on the slider is proposed. This solution reduces the actuation forces, thus enabling direct flow control actuation through an electronic control system. The proposed solution is cost effective, it consists of a limited number of parts, and it is suitable for pumps without pressure compensation, i.e. for low or intermediate pressures. The paper details the aspects of the pump design, which was performed by using a multi-objective algorithm that maximizes the flow operating range and at the same time the pump. The optimum design could achieve a flow variation of about 32% in simulation and this was also demonstrated in actual experiments on a prototype realized at the author’s Research Center. The proposed design can impact several of the current applications of external gear pumps, introducing the additional “flow on demand” capability.

External Gear Pump Model and Simulation

2011 ◽  
Vol 127 ◽  
pp. 228-232 ◽  
Author(s):  
Hui Wang ◽  
Sha Sha Du
Keyword(s):  
Simulation Analysis ◽  
Gear Pump ◽  
Structural System ◽  
Pump Design ◽  
Gear Mesh ◽  
Mesh Model ◽  
Model And Simulation ◽  
Gear Pumps ◽  
The Impact ◽  
External Gear Pump

This paper describes the development of gear pumps and the main causes of noise,and establish the overall dynamic model of external gear pump,mainly including the trapped oil model,the gear mesh model and the shell model and then go on with simulation analysis and research.Through establishment the gear pump model,it is benefit for predicting the gear pump trapped oil pressure and studying the impact of parameter changes on the pressure,and getting the natural frequencies and model shapes of the gear pump structural system,so that we can analysis external gear pump vibration and assess gear pump design optimization,while helping to find the effective measures to control gear pump noise and ease trapped oil phenomenon.

Computer Prediction of Cyclic Excitation Sources for an External Gear Pump

1985 ◽  
Vol 199 (3) ◽  
pp. 175-180 ◽  
Author(s):  
K Foster ◽  
R Taylor ◽  
I M Bidhendi
Keyword(s):  
Computer Program ◽  
Gear Pump ◽  
Computer Prediction ◽  
Pressure Distributions ◽  
External Gear Pumps ◽  
Theoretical Predictions ◽  
Gear Pumps ◽  
External Gear Pump

A description is given of a computer program for investigating the performance of the external gear pumps under varying conditions with the special emphasis on the examination of pressure distributions within the pump, i.e. excitation forces for the vibration of the pump case and the variation in flow generated by the pump. Measurements are presented for the variation with time of tooth space pressure and the results are compared with the theoretical predictions from the computer program.

Experimental Investigation of Flowrate Irregularity in Rotary Gear Pumps

1992 ◽  
Author(s):  
G. Mimmi
Keyword(s):  
Experimental Investigation ◽  
Flow Rate ◽  
Experimental Tests ◽  
Periodic Variation ◽  
Experimental Results ◽  
Gear Pump ◽  
Gear Pumps ◽  
Hot Film ◽  
Instantaneous Flow Rate ◽  
External Gear Pump

Abstract In a previous paper the author proposed a method to reduce the periodic variation in flow rate for an external gear pump. To verify the experimental results, a series of experimental tests on a expressly realized gear pump, was carried out. The pump was equipped with relieving grooves milled into the side plates. The tests were done on a closed piping specifically realized and equipped for measuring the instantaneous flow rate of the fluid through a wedge-shaped hot film probe.

Review of Gear Pump Development at NRL

2020 ◽  
Author(s):  
Logan T. Williams
Keyword(s):  
System Development ◽  
Design Guidelines ◽  
Lessons Learned ◽  
Naval Research ◽  
Gear Pump ◽  
Pump Design ◽  
External Gear Pumps ◽  
Gear Pumps ◽  
Original Goal ◽  
Small Form Factor

Abstract Research into hydraulic quadrupeds at the US Naval Research Laboratory (NRL) has created the demand for in-house development of miniaturized hydraulic components, including pumps. As part of this effort to develop a miniaturized hydraulic powertrain, external gear pumps were examined, designed, and iterated upon to create an efficient pump package with a small form factor (1.5 × 1.6 × 1.8 inches). The evolution of the pump design has touched every component of the pump and has resulted in many practical design guidelines, novel pump components, and improved pump analysis tools. The original goal of developing the capability for integrated hydraulic powertrain components, such as embedding the pump into the quadruped’s hydraulic manifold, was to enable further compaction and streamlined system development. An additional result of the project was the accumulation of gear pump design fundamentals and lessons learned that can benefit any pump designer.

Vibroacoustic Measurements and Simulations Applied to External Gear Pumps. An Integrated Simplified Approach

2016 ◽  
Vol 41 (2) ◽  
pp. 285-296 ◽  
Author(s):  
Eleonora Carletti ◽  
Giuseppe Miccoli ◽  
Francesca Pedrielli ◽  
Giorgio Parise
Keyword(s):  
Complex Dynamics ◽  
Gear Tooth ◽  
Fluid Pressure ◽  
Sound Intensity ◽  
Integrated Approach ◽  
Gear Pump ◽  
Simplified Approach ◽  
Noise Field ◽  
Gear Pumps ◽  
External Gear Pump

Abstract This paper describes the development phases of a numerical-experimental integrated approach aimed at obtaining sufficiently accurate predictions of the noise field emitted by an external gear pump by means of some vibration measurements on its external casing. Harmonic response methods and vibroacoustic analyses were considered as the main tools of this methodology. FFT acceleration spectra were experimentally acquired only in some positions of a 8.5 cc/rev external gear pump casing for some working conditions and considered as external excitation boundary conditions for a FE quite simplified vibroacoustic model. The emitted noise field was computed considering the pump as a ‘black box’, without taking into account the complex dynamics of the gear tooth meshing process and the consequent fluid pressure and load distribution. Sound power tests, based on sound intensity measurements, as well as sound pressure measurements in some positions around the pump casing were performed for validation purposes. The comparisons between numerical and experimental results confirmed the potentiality of this approach in offering a good compromise between noise prediction accuracy and reduction of experimental and modelling requirements.

The Flow Pulsation Analysis of an External Gear Pump

2011 ◽  
Vol 236-238 ◽  
pp. 2327-2331
Author(s):  
Yan Zhi Li ◽  
Li Huan Gao ◽  
Xiao Yang Tang
Keyword(s):  
Pulse Amplitude ◽  
Gear Pump ◽  
Flow Pulsation ◽  
Flow Ripple ◽  
Pump Flow ◽  
External Gear Pumps ◽  
Tooth Width ◽  
Different Types ◽  
Gear Pumps ◽  
External Gear Pump

In this paper, the theoretical flow ripple of an external gear pump is studied for pumps of similar size using different numbers of teeth on the driving and driven gears. External gear pumps with three different types of tooth profiles are studied. Nondimensional flowrates and fluctuation coefficients of gear pumps are discussed. By using the formula, flowrates can be calculated accurately and efficiently. Results indicate that: in the case of the same displacement (except teeth number and tooth width, other parameters of the gear pump are the same) the gear pump flow pulsation decreases with the increasing of the teeth number. We also concluded that changing tooth profiles on the driving and driven gear can get different pulse amplitude of the flow ripple.

Experimental Validation of a Model for the Dynamic Analysis of Gear Pumps

2013 ◽  
Author(s):  
Emiliano Mucchi ◽  
Giorgio Dalpiaz
Keyword(s):  
Experimental Validation ◽  
Gear Pump ◽  
Test Plate ◽  
Operational Conditions ◽  
Experimental Apparatus ◽  
Gear Pumps ◽  
Force Components ◽  
Set Up ◽  
The Time Domain ◽  
External Gear Pump

This paper concerns the experimental validation of an elastodynamic model of an external gear pump for steering systems in vehicles. The elastodynamic model takes into account the most important phenomena involved in the operation of this kind of machines. Two main sources of noise and vibration can be considered: pressure and gear meshing. An experimental apparatus has been set up for the measurements of the case accelerations and force components in operational conditions. The model was validated by comparison between simulations and experimental results concerning forces and moments: it deals with the external and inertia components acting on the gears, estimated by the model, and the reactions and inertia components on the pump case and the test plate, obtained by measurements. The validation is carried out comparing the level of the time synchronous average in the time domain and the waterfall maps in the frequency domain, with particular attention to identify system resonances. The validation results are globally satisfactory.

scholarly journals The Influence of Radial and Axial Gaps on Volumetric Efficiency of External Gear Pumps

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4468
Author(s):  
Paulina Szwemin ◽  
Wieslaw Fiebig
Keyword(s):  
Fluid Flow ◽  
Volumetric Efficiency ◽  
Operating Parameters ◽  
Gear Pump ◽  
Cfd Model ◽  
External Gear Pumps ◽  
Flow Phenomena ◽  
Gear Pumps ◽  
The Impact ◽  
External Gear Pump

The design of gear pumps and motors is focused on more efficient units which are possible to achieve using advanced numerical simulation techniques. The flow that appears inside the gear pump is very complex, despite the simple design of the pump itself. The identification of fluid flow phenomena in areas inside the pump, considering the entire range of operating parameters, is a major challenge. This paper presents the results of simulation studies of leakages in axial and radial gaps in an external gear pump carried out for different gap shapes and sizes, as well as various operating parameters. To investigate the processes that affect pump efficiency and visualize the fluid flow phenomena during the pump’s operation, a CFD model was built. It allows for a detailed analysis of the impact of the gears’ eccentricity on leakages and pressure build-up on the circumference. Performed simulations made it possible to indicate the relationship between leakages resulting from the axial and radial gap, which has not been presented so far. To verify the CFD model, experimental investigations on the volumetric efficiency of the external gear pump were carried out. Good convergence of results was obtained; therefore, the presented CFD model is a universal tool in the study of flow inside external gear pumps.

Theoretical Analysis and Design of a Variable Delivery External Gear Pump for Low and Medium Pressure Applications

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Srinath Tankasala ◽  
Andrea Vacca
Keyword(s):  
High Pressures ◽  
Optimization Approach ◽  
Gear Pump ◽  
Flow Variation ◽  
Analysis And Design ◽  
Target Pressure ◽  
Electric Actuation ◽  
Variation Mechanism ◽  
Instantaneous Flow Rate ◽  
External Gear Pump

This paper describes a unique design concept that is capable of electronically controlling the flow delivered by an external gear pump (EGP). The principle used for varying the flow relies on the variable timing concept which has been previously demonstrated by the author's research team for EGP's operating at high pressures (HPs) (p > 100 bar). This principle permits to vary the flow within a certain range, without introducing additional sources of power loss. In this paper, the above concept has been applied to formulate a design for a variable delivery EGP for low pressure (LP) applications (p < 30 bar), suitable for direct electric actuation. Specific design principles for the gear and the flow variation mechanisms are introduced to limit the force required by the electric actuation, and for maximizing the flow variation range. Also, the low target pressure allows the variable timing principle to be realized with an asymmetric solution, with only one variable timing element present at one side of the gears. A detailed analysis concerning the relationship between the electrically commanded position of the flow varying element and the theoretical flow delivered by the pump is also presented. This analysis is used to formulate analytical expressions for the instantaneous flow rate and the flow nonuniformity of the pump. The paper details the design principle of the proposed variable flow pump and describes the multi-objective optimization approach used for sizing the gears and flow variation mechanism. The paper also discusses the experimental activity performed on a prototype of the proposed unit, able to achieve a flow variation of 31%.

A Numerical Procedure to Design the Optimal Axial Balance of Pressure Compensated Gear Machines

2014 ◽  
Author(s):  
Divya Thiagarajan ◽  
Andrea Vacca
Keyword(s):  
Numerical Procedure ◽  
Operating Conditions ◽  
Force Balance ◽  
Gear Pump ◽  
Power Losses ◽  
Outlet Port ◽  
External Gear Pumps ◽  
Gear Pumps ◽  
Force Components ◽  
External Gear Pump

This paper presents an innovative numerical procedure to determine the optimal balancing area of lateral bushes in external gear pumps or motors. In pressure compensated designs of external gear machines, the lateral bushes perform the important functions of sealing the tooth space volumes while they transfer fluid from the inlet to the outlet port. In normal operating conditions, a lubricating gap exists between the lateral bush and the gear permitting to minimize losses due to shear stress and leakage. These conditions are found by determining proper balancing areas at the side of the bushes not facing the gears, in which the pressure of the high pressure port is properly established. This problem is also known as “axial balance” of external gear machines. To determine the optimal axial balance which minimizes the power losses associated with the lubricating gap in all operating conditions, all the static and hydrodynamic forces acting on the lateral bushes have to be considered. This delicate aspect of external gear units design is usually addressed through empirical procedures; while in this paper an automatic numerical procedure is presented. The proposed method is based on the solution of the force balance of the lateral bushes, taking into account all force components, including the hydrodynamic terms due to the relative inclination between bushes and gears and material deformation. After detailing the procedure, the paper describes its potentials by showing the advantages arising from the optimization of the axial balance of a particular external gear pump for fluid power applications.

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