6 Modelling of Operational Cycle in a Hydraulic Drive Based on Adjustable Axial Piston Hydraulic Machines

In this study, sound measurements of an axial piston pump and an internal gear pump were performed and subjective pleasantness judgements were collected in listening tests (to analyze the subjective pleasantness), which could be seen as the inverse of the subjective annoyance of hydraulic drives. Pumps are the dominant sound source in hydraulic systems. The noise generation of displacement machines is subject of current research. However, in this research only the sound pressure level (SPL) was considered. Psychoacoustic metrics give new possibilities to analyze the sound of hydraulic drive technology and to improve the sound quality. For this purpose, instrumental measurements of the acoustic and psychoacoustic parameters are evaluated for both pump types. The recorded sounds are played back to the participants in listening tests. Participants evaluate them regarding the subjective pleasantness by means of paired comparison, which is an indirect scaling method. The dependence of the subjective pleasantness on speed and pressure was analyzed for both pump types. Different regression analyses were carried out to predict the subjectively perceived pleasantness or annoyance of the pumps. Results show that a lower speed is the decisive operating parameter for reducing both the SPL and the annoyance of a hydraulic pump.

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The method of dynamic operating modes investigation in electrohydraulic drive systems with improved accuracy of positioning executive elements

MATEC Web of Conferences ◽

10.1051/matecconf/201822604024 ◽

2018 ◽

Vol 226 ◽

pp. 04024

Author(s):

Valeriy V. Grechikhin ◽

Galina A. Galka ◽

Anatoliy I. Ozerskiy ◽

Mikhail E. Shoshiashvili

Keyword(s):

Mutual Influence ◽

Hydraulic Drive ◽

Joint Work ◽

Operating Modes ◽

Hydraulic Machines ◽

Dynamic Operating ◽

Electrohydraulic Drive ◽

Drive Systems ◽

Improved Accuracy ◽

Executive Elements

The article describes the method of dynamic operating modes investigation in electrohydraulic drive systems with improved accuracy of positioning output element. The method is the evolution of the fundamental positions of the mechanics of continuous media with moving boundaries as applied to the research of non-stationary processes accompanying the operation of hydraulic drive systems with piston hydraulic machines. The method is based on generalized modeling (technical, physical, mathematical and computer), takes into account the peculiarities of mutual influence of electric and hydraulic machines during their joint work as part of the electrohydraulic drive, which raises the level and adequacy of actuators simulation, as well as the reliability of the assessment of their technical condition. The method extends the field of research, improves the accuracy of the calculation of the positioning of the executive elements, taking into account the different dynamic modes of the drives under study.

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Theoretical background of hydraulic drive control system analysis for testing piston hydraulic cylinders

Vestnik of Don State Technical University ◽

10.23947/1992-5980-2019-19-3-242-249 ◽

2019 ◽

Vol 19 (3) ◽

pp. 242-249 ◽

Cited By ~ 2

Author(s):

A. T. Rybak ◽

I. K. Tsybriy ◽

S. V. Nosachev ◽

A. R. Zenin

Keyword(s):

Mathematical Modeling ◽

Hydraulic System ◽

Energy Recovery ◽

Test Bench ◽

Hydraulic Drive ◽

Mechanical Transmission ◽

Hydraulic Motor ◽

Hydraulic Machines ◽

Life Tests ◽

Hydraulic Cylinders

Introduction. The durability and performance of hydraulic machines is determined through life tests. At that, various braking devices (mechanical, electric, hydraulic, etc.) are used for strength loading of the hydraulic motor, as a result of which a significant amount of energy is lost. This can be avoided if the method of rotational motion with energy recovery is used during life tests. This approach is applicable for hydraulic pumps, motors, and hydraulic cylinders.Materials and Methods. A test bench is presented, the design of which provides recreation of the conditions most appropriate for the field operation of hydraulic cylinders. In this case, energy recovery is possible. To solve the research problems, methods of mathematical modeling were used, the basic functional parameters of the proposed design were calculated. The determination of the pressure increment at various points in the hydraulic system is based on the theory of volumetric rigidity. When modeling the motion of the moving elements of the bench hydraulic system, the laws of rotor motion are used.Research Results. In the structure of the test bench, the cylinders in question are located in the pressure main between the hydraulic pump and the hydraulic motor. This enables to significantly reduce the bench itself and to save a significant amount of energy due to its recovery. A basic hydraulic diagram of the test bench for piston hydraulic cylinders is presented, in which the operation of the moving elements of the system is shown. A mathematical modeling of the hydraulic system of the bench is performed. A kinematic diagram of the mechanism for transmitting motion between test cylinders is shown.Discussion and Conclusions. The system of equations presented in the paper shows how the increment of pressure at the selected nodal points of the energy recovery system is determined (in particular, how the increment depends on time, reduced coefficient of volumetric rigidity, operating fluid consumption, and piston areas). The velocities of the hydraulic pistons are determined according to the kinematic scheme of the mechanical transmission of the bench. Thus it can be argued that, thanks to the solution presented in the paper, the life test results of hydraulic cylinders will adequately reflect their operation under rated duties.

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Hydraulics

10.12737/1045063 ◽

2020 ◽

Author(s):

Sergey Vol'vak

Keyword(s):

Graduate Students ◽

Water Supply ◽

Hydraulic Drive ◽

Study Guide ◽

Agricultural Water ◽

Field Of Study ◽

Hydraulic Machines ◽

Agricultural Water Supply

Study guide corresponds to the program discipline "Hydraulics" and consists of two parts: "Hydraulics and hydraulic machines" and "the Dredging of agricultural processes". This course focuses on the theory of hydraulics, design and operation of hydraulic machines, fans, compressors and other means of dredging of agricultural processes, provides information about the hydraulic drive, the basics of reclamation and mechanized irrigation and agricultural water supply, data on hydropneumatische in agriculture. For students of all forms of education in field of study 35.03.06 "Agroengineering", as well as for graduate students, teachers and technical workers of agriculture.

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Stochastic models for ensuring parametric reliability of the construction machines

Strength of Materials and Theory of Structures ◽

10.32347/2410-2547.2021.106.262-273 ◽

2021 ◽

pp. 262-273

Author(s):

Galyna Getun ◽

Vitalii Les'ko ◽

Iryna Bezklubenko ◽

Olena Balina ◽

Yurii Butsenko

Keyword(s):

Methodological Approach ◽

Hydraulic Drive ◽

Hydraulic Cylinder ◽

Technical Condition ◽

Technical Problems ◽

Reliability Models ◽

Reliability Indicators ◽

Hydraulic Machines ◽

Parametric Reliability ◽

Analysis Of Failures

The solution of technical problems to ensure the working capacity is largely determined by the effectiveness of theoretical and applied developments in an area of estimation and prediction of their reliability indicators. An effective approach to the analysis of failures and the development of operability and parametric reliability models provides an opportunity to obtain more adequate models of reliability of hydraulic drives of machines, as they more fully take into account the specifics of the structure and functioning of the hydro drive elements of construction machines, their relationships and features of the formation of parameters failures. And this will allow to get more real and accurate results of estimation of reliability indicators of hydraulic drives of both construction and other hydraulic machines. They do not exhaust all possible variants of models that can take place when analyzing the reliability of hydraulic drives of machines, but at the same time they to a certain extent extend and refine the set of known reliability models. Specific in terms of formation of parametrical failures are such consistently connected in terms of the layout of hydraulic elements, as working sections of hydraulic distributors and hydraulic cylinders, which are part of the subsystems of GPs and form the so-called functional areas (FA). Reaching the FA limit is a compatible result of the combined random process of evolution of the volumetric efficiency JCUA these elements, and the technical condition of the FA is estimated to be generalized by the JCUA, which equals the product of the JCUA of consecutively connected elements: . In this case, the probability of maintaining the capacity of the FA will be: . The processing of diagnostic information and the study of the reliability of GPs in real conditions of their operation showed that the distribution of JCUD hydraulic elements with a sufficient degree of consistency can be described under several theoretical laws. It is considered when the JCUA sections of the hydraulic distributor and hydraulic cylinder are distributed by gamma distribution and exponential distribution. The use of the general methodological approach to the analysis of failures and the construction of models of operability and parametric reliability provides an opportunity to obtain more adequate models of reliability of hydraulic drives of machines, as they more fully take into account the specifics of the structure and functioning of the hydraulic drive elements, They don't exhaust all possible models that can take place when analyzing the reliability of hydraulic drives, but at the same time they are to some extent expanding and refining the range of already known models of reliability.

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ANALYSIS OF UNIVERSAL CHARACTERISTICS OF HYDRAULIC FLUID POWER TRANSMISSIONS OPERATING IN A COMPOSITION OF HYDRAULIC-MECHANICAL TRANSMISSIONS FOR DIFFERENT WORKING VOLUMES OF HYDRAULIC MACHINES OF AXIAL PISTON TYPE

Bulletin of the National Technical University «KhPI». Series: Automobile and Tractor Construction ◽

10.20998/2078-6840.2020.2.02 ◽

2020 ◽

Vol 0 (2) ◽

pp. 11-18

Author(s):

Vadym Samorodov ◽

Grigorii Avrunin ◽

Dmitrii Harmash

Keyword(s):

Fluid Power ◽

Hydraulic Fluid ◽

Hydraulic Machines ◽

Axial Piston ◽

Mechanical Transmissions

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Ways to ensure the efficiency and improvement the efficiency of hydraulic machines

Journal of Physics Conference Series ◽

10.1088/1742-6596/2094/4/042090 ◽

2021 ◽

Vol 2094 (4) ◽

pp. 042090

Author(s):

A S Lunev ◽

A S Kaverzina ◽

I V Karnaukhov ◽

M D Pankiv ◽

I V Andreychikov

Keyword(s):

Hydraulic Drive ◽

Energy Losses ◽

Minimal Energy ◽

Hydraulic Systems ◽

Environmental Friendliness ◽

Hydraulic Machines

Abstract In this paper, the methods of designing hydraulic drives with minimal energy losses are considered. As well as ways to reduce energy losses in hydraulic systems. The importance of the work is due to the fact that methods have been proposed to improve the reliability and environmental friendliness of the hydraulic drive.

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Measuring system for monitoring the polydimensional deformation of superstructures of bridges and over-bridges improvement of volume hydraulic drive construction and road machines using flow shareholders

Bulletin of Kharkov National Automobile and Highway University ◽

10.30977/bul.2219-5548.2021.95.0.7 ◽

2021 ◽

pp. 7

Author(s):

Igor Pimonov

Keyword(s):

Service Life ◽

Hydraulic Drive ◽

Road Construction ◽

Measuring System ◽

Working Fluid ◽

Return Flow ◽

Flow Divider ◽

Working Volume ◽

Hydraulic Machines ◽

Hydraulic Motors

Due to its advantages, the hydraulic drive is widely used in road construction machines. Depending on its design, the share of the hydraulic drive, which is the most expensive unit of a road construction machine, accounts for thirty to eighty percent of all failures. Reliable hydraulic drive, provides, to a large extent, the reliability of the whole machine and the efficiency of the construction organization as a whole. The efficiency of the hydraulic drive of construction machines, and, as a consequence, the machines themselves, is ensured by a set of measures, among which the most important is the quality design, manufacture and operation, combined into a single structural system. Depending on the quality of cleaning of the working fluid, the service life of hydraulic machines can be increased or decreased several times. Accumulation of pollutants in the hydraulic drive, the hardness of which is significantly higher than the hardness of metals, causes rapid wear of the surfaces of hydraulic units and the service life is rapidly reduced. Cavitation in the pump is accompanied by a pulsation of fluid pressure and noise. These pulsations are due to the return flow of fluid from the discharge cavity of the pump, which is accompanied by hydraulic shocks and as a result of alternating shocks, a pressure pulsation in the discharge line of the pump. The amplitude of these pulsations can, under known conditions, reach a value that causes the destruction of the pump. The possibility of cavitation can be reduced by rational choice of modes of operation of the hydraulic system and the correct design of its units, but this phenomenon can be completely eliminated only by using auxiliary pumping pumps, as well as increasing the pressure in the suction line of the pump. On the basis of the analysis of perspective directions of improvement of the hydraulic drive of the excavator the following improved scheme of it is developed. Usually only high-flow hydraulic motors can be used in flow dividers. But in our case it is necessary that the device had, first of all, small mechanical losses and small cost, and accuracy of division of working liquid which follows on filters can be small. In the volume flow divider, hydraulic motors are used: gear, piston, vane, screw, roller. The simplest dividers of volume type are paired (connected by shafts) hydraulic motors of lamellar (vane) and roller types. Hydraulic motors in this scheme are flow measuring devices (dispensers), which supply for one revolution the volume of liquid, equal without taking into account the leaks in the hydraulic motor, its working volume. The use of a flow divider as a source of hydraulic energy makes it possible to improve the hydraulic drive by combining in a single system the purification of the working fluid and the ejector feed of the pump. The most promising, in terms of cost, are flow dividers based on vane and rotary hydraulic motors..

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