Mechanical vibrations and flow fluctuation give rise to complex interactive vibration mechanisms in hydraulic pumps. The working conditions for a hydraulic pump are therefore required to be improved ...in the design stage or as early as possible. Considering the structural features, parameters, and operating environment of a hydraulic plunger pump, the vibration modes for two-degree-of-freedom system were established by using vibration theory and hydraulic technology. Afterwards, the analytical form of the natural frequency and the numerical solution of the steady-state response were deduced for a hydraulic plunger pump. Then, a method for the vibration analysis of a hydraulic pump was proposed. Finally, the dynamic responses of a hydraulic plunger pump are obtained through numerical simulation.
Introduction
Proper maintenance policy can play a vital role for effective investigation of product reliability. Every engineered object such as product, plant or infrastructure needs preventive and ...corrective maintenance.
Case description
In this paper we look at a real case study. It deals with the maintenance of hydraulic pumps used in excavators by a mining company. We obtain the data that the owner had collected and carry out an analysis and building models for pump failures. The data consist of both failure and censored lifetimes of the hydraulic pump.
Discussion and evaluation
Different competitive mixture models are applied to analyze a set of maintenance data of a hydraulic pump. Various characteristics of the mixture models, such as the cumulative distribution function, reliability function, mean time to failure, etc. are estimated to assess the reliability of the pump. Akaike Information Criterion, adjusted Anderson–Darling test statistic, Kolmogrov–Smirnov test statistic and root mean square error are considered to select the suitable models among a set of competitive models. The maximum likelihood estimation method via the EM algorithm is applied mainly for estimating the parameters of the models and reliability related quantities.
Conclusions
In this study, it is found that a threefold mixture model (Weibull–Normal–Exponential) fits well for the hydraulic pump failures data set. This paper also illustrates how a suitable statistical model can be applied to estimate the optimum maintenance period at a minimum cost of a hydraulic pump.
In this paper, authors show a cost-saving method of replacing variable flow pumps with pressure regulator within hydraulic balancing systems for heavy machine-tools, with simple, constant flow pumps. ...The system proposed is relevant for heavy machine-tools where large loads need balancing: cross beams, slides, enclosures, etc. The basic hydraulic schematics, calculation method and results of certain simulations are displayed here. A characteristic of these systems is the use of routine hydraulic equipment, thus providing low costs. Hydraulic equipment used in such balancing systems may successfully replace complex and expensive equipment used in feeding/positioning kinematic chains within CNC heavy machine-tools, like: Horizontal Boring and Milling Machines (HBM), Vertical Lathes (VL) and Gantry Machines. Keywords: heavy machine-tools; feeding/positioning kinematic chain; hydraulic balancing; low power consumption.
Much research dealt with the problem in the pulsation of hydraulic pumps, studies, research and literature for vibration did not interfere with the effect of the medium which make vibrations and ...effect of temperature on the medium (the indirect effect on mechanical vibration). In this research a practical correlation between pulsation of pumps and temperature, pressure and vibration will be developed. To achieve this goal the hydraulic system was designed and implemented to deduce the effect of the internal design of the three main hydraulic pumps, gear pump, vane pump and piston pump, in conjunction with the high temperature of the mineral oil on the vibration generated by the piston arm and the stability of the actuator. Vibration Meter device used to indicate the vibration at the tip of the arm plunger for hydraulic piston and uploaded with a variable load (spring), as well as a computer-aided reading was recorded. It was shown that the interior design of the pumps had an effective influence on the values of acceleration and speed of vibration, even if convergence frequency pulse outside of the slot pressure pumps. This effect cannot be separated from the oil temperature which affect the increasing values of acceleration and speed of vibration recorded on the tip of the plunger arm (performance of the piston) also the pressure has an effect on the values of acceleration and speed of vibration . The temperature of the mineral oil had a strong influence on the performance of hydraulic systems, at the resonance condition.
A novel type of an axial, piston-driven high pressure hydraulic pump with variable capacity marks a significant improvement in the area of the hydraulic machinery design. Total discharge from ...hydrostatic forces eliminates a need for a servomechanism, thus simplifying operation, reducing weight and introducing the possibility of the pump displacement control by computer. PWK-type pumps, invented in the Gdansk University of Technology, offer high efficiency for pressure levels up to 55 MPa, ability to work self sucking even at high speed. However, the heart of the new invention, the commutation unit, creates harmful pressure peaks. Those peaks can be mitigated by the introduction of a compensation chamber with elastic walls. Owing to the dynamic character of events taking place in the pump, a need for computer simulation arouse in order to understand phenomena leading to the occurrence of pressure peaks and choose compensation chamber parameters accordingly. A CFD package alone would not be sufficient to reliably represent the interaction between the compensation chamber wall and the working fluid. This paper presents Fluid Structure Interaction approach comparing 3 different models: 2 simplified models of the pump and a full pump model.
Nowa odmiana wysokocisnieniowej pompy tłokowej osiowej o zmiennej wydajnosci stanowi znaczacy postep w projektowaniu systemów napedu hydraulicznego. Całkowite odciazenie od sił hydrostatycznych pozwala wyeliminowac serwomechanizm sterujacy, upraszczajac konstrukcje pompy, zmniejszajac jej ciezar i pozwalajac na komputerowe sterowanie wydajnoscia. Pompy typu PWK, wynalezione na Politechnice Gdanskiej, osiagaja wysoka sprawnosc przy cisnieniu siegajacym 55 MPa i sa samossawne nawet przy wysokiej predkosci obrotowej. Mechanizm rozrzadu krzywkowego, bedacy podstawa wynalazku, generuje jednak szkodliwe piki cisnienia. W celu ich zredukowania zaproponowano zastosowanie komory kompensujacej z elastycznymi scianami. Ze wzgledu na dynamiczny charakter zjawisk zachodzacych podczas pracy pompy w celu przeanalizowania genezy pików cisnienia i doboru własciwych parametrów konstrukcyjnych komory kompensacyjnej konieczne było przeprowadzenie symulacji komputerowej. Dostepne pakiety CFD nie były jednak w stanie odwzorowac złozonych zaleznosci miedzy sciana komory kompensacyjnej a ciecza robocza. Zaprezentowane w artykule podejscie ukazuje oddziaływania miedzy ciecza a struktura pompy na przykładzie 3 róznych modeli: dwóch uproszczonych i pełnego modelu pompy
Hydraulic pump is the heart of hydraulic system, therefore a real-time condition monitoring for hydraulic pump is crucial to the reliability of the entire system. In this study, a method for ...performance assessment and fault diagnosis to hydraulic pump based on wavelet packet transform (WPT) and Self-organizing mapping (SOM) neural network is proposed. First, WPT is utilized to decompose the vibration signal into components, energy of each component is extracted and normalized to form the feature vector. Second, SOM neural network, trained only by normal data, is used to map feature vectors into Minimum Quantization Error (MQE), which is then normalized into confidence values (CV). Performance assessment is accomplished by tracking the trends of CVs. Finally, when faults occur, SOM, trained by both normal and faulty samples, is employed to classify the faults into different groups, which delegates different fault modes of the hydraulic pump. In addition, Taguchi method is used to reduce the redundant features and extract the principal components to ensure the effectiveness of the approach. A case study based on the vibration dataset of test plunger pump rig is conducted to demonstrate that the proposed method is able to assess the performance of hydraulic pump and diagnose faults suitably.
The growing demand for the safety and reliability in industries triggers the development of condition monitoring and fault diagnosis technologies. Hydraulic pump is the critical part of a hydraulic ...system. The diagnosis of hydraulic pump is very crucial for reliability. This paper presents a method based on information- geometric support vector machine (IG-SVM), which is employed for fault diagnosis of hydraulic pump. The IG-SVM, which uses information geometry to modify SVM, improves the performance in a data-dependent way. To diagnose faults of hydraulic pump, a residual error generator is designed based on the IG-SVM. This residual error generator is firstly trained using data from normal state. Then, it can be used for fault clustering by analysis of the residual error. Its feasibility and efficiency has also been validated via a plunger pump test-bed.
Fluid power systems are manufactured by many organizations for a very wide range of applications, which often embody differing arrangements of components to fulfill a given task. Hydraulic components ...are manufactured to provide the control functions required for the operation of a wide range of systems and applications.
Due to the fact of a simple and robust cross-section design switched reluctance machines are perfectly suited to drive hydraulic pumps; either as a dry-running version or as a canned version for ...seal-less applications. The setup of the test bench is given as well as the performance (torque, losses, and efficiency) of both versions are analyzed and compared to each other. Both motors have the same cross-section design except the two can shields for the canned version and both drives operate with the same power electronic at the same working conditions.
Este trabajo fue desarrollado con el propósito de fabricar un banco de pruebas de bombas hidráulicas portátil para aplicaciones didácticas para así estudiar el flujo de fluidos y sus características ...en el cual pudo desarrollar experiencias prácticas en el área de ingeniería, conociendo así como se maneja en el ámbito laboral e industrial el comportamiento de este, Por lo tanto este trabajo desarrollado fue sustentado por teorías de Bombas, Teoría, Diseño y aplicaciones, Maxtais (2009), Ciencia de los materiales, Smith (2001), Resistencia de los Materiales, Mott (2009), Introducción a la Ingeniería, White (2011). Por otra parte, la presente investigación se encontró en la modalidad de proyecto de tipo factible por consiguiente se usó la técnica de recolección de datos, como el manejo de técnicas de estadísticas, observación directa, entre otras. Finalmente, se realizaron procedimientos prácticos para la construcción de la planta piloto, como la de parametrización del diseño del mismo, la selección tanto de materiales como equipos, al igual que el diseño de este plasmado en planos acotados con la utilización de AutoCAD 2015 ®, desarrollando de esta forma las 5 etapas u fases de la fabricación de esta herramienta de estudio las cuales fueron validada por razón de la presión de operación, desempeño, cabezal y robustez de este.
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