scholarly journals 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

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..

scholarly journals Justification of the Kinematic Diagrams for the Distribution System of a Planetary Hydraulic Motor

2018 ◽  
Vol 7 (4.3) ◽  
pp. 6 ◽  
Author(s):  
Angela Voloshina ◽  
Anatolii Panchenko ◽  
Oleg Boltynskiy ◽  
Igor Panchenko ◽  
Olena Titova
Keyword(s):  
Distribution System ◽  
Hydraulic System ◽  
Hydraulic Drive ◽  
Fluid Distribution ◽  
Working Fluid ◽  
Hydraulic Motor ◽  
Hydraulic Motors ◽  
Output Characteristics ◽  
Kinematic Diagram ◽  
The Impact

The output characteristics of a planetary (orbital) hydraulic motor could be significantly improved if the kinematic diagrams for its working fluid distribution system are chosen correctly and substantiated. Fluctuations in the flow of the power fluid cause pulsation in the cavity of the input pressure of the hydraulic motor. This results to vibration of the hydraulic system elements. Thus, the hydraulic motor can be considered as a source of pulsation which leads to functional failures of the hydraulic system. As they run at low rotational speeds with high torque, planetary hydraulic motors are commonly applied for a hydraulic drive in active working tools of self-propelled machinery. It has been established that one of the main components of a planetary hydraulic motor, which causes pressure pulsations, is its distribution system. The frequency and amplitude of these pulsations depends on the kinematic diagram for the distribution system of the power fluid. Therefore, we studied how the kinematic diagram for the distribution system effects on the output characteristics of a planetary motor. Since the change in the capacity of a distribution system with various kinematic diagrams influences on the output characteristics of a planetary motor, the impact was investigated. The kinematic diagrams, which improve the output characteristics of planetary hydraulic motors, were justified. 

scholarly journals EXPERIMENTAL RESOURCE STAND RESEARCH OF THE GOLDEN DIVISION DISTRIBUTOR

2019 ◽  
pp. 80-86
Author(s):  
Volodymyr Rutkevych
Keyword(s):  
Hydraulic Drive ◽  
Operating Conditions ◽  
Working Fluid ◽  
Stable Operation ◽  
Initial Stage ◽  
Flow Divider ◽  
Main Components ◽  
Working Bodies ◽  
Cost Characteristics

The article discusses and analyzes the operating conditions of a modern hydraulic drive. Despite the difficult operating conditions of modern agricultural machinery (difficult working conditions, frequent changes in the technological load on the working bodies, low quality of the working fluid, increased dust content and temperature fluctuations), the hydraulic drive is its main reliable element. The basis of hydraulic drives is hydraulic spool type devices, they remain the main components of a modern hydraulic drive, are able to increase energy, dynamic, cost characteristics and increase the reliability and durability of this drive. The advantages, disadvantages and directions of improvement of this drive are noted. The modern directions of development of the hydraulic drive aimed at increasing the reliability, durability and adaptability to changing the technological load on the working bodies are considered. A booth design is proposed that allows to investigate a resource study of the developed spool splitter of a forage stem feeder. As a result of the research at the initial stage, some shortcomings in the structural implementation of the developed spool of the flow divider at the time up to 2·104 cycles were revealed. After analyzing the operating conditions and making changes to the design of the stem feeder spacer spacer and retesting, the spacer spacer showed stable operation, with more than 6.6·105 load cycles.

Mechanical Response Analysis of the Composite Asphalt Pavement

2014 ◽  
Vol 1023 ◽  
pp. 28-31
Author(s):  
Li Min Li
Keyword(s):  
Service Life ◽  
Mechanical Response ◽  
Asphalt Pavement ◽  
Road Construction ◽  
Pavement Design ◽  
Rigid Base ◽  
Response Analysis ◽  
Early Failure ◽  
Short Service Life ◽  
Design Software

With the constant increasing of traffic flow and axle load, the early failure of semi-rigid base asphalt pavement is increasingly serious in China. The bad durability and short service life of pavement have become main obstacles in road construction development. Based on the experience of successful application, the early failure of semi-rigid base asphalt pavement is solved, and the service life of pavement is increased by using of the composite asphalt pavement. To solve the design problem of the composite asphalt pavement , its mechanical properties influence results of are obtained by the factors, such as shear strain, shear stress, compression strain on top of subgrade, etc, by a lot of calculation using Shell pavement design software. These provide theoretical basis for durable asphalt pavement design based on rut-resistance property.

ENSURING QUALITATIVE-ACCURACY CHARACTERISTICS DURING RESTORING OF VEHICLE PARTS

2021 ◽  
Vol 3 (144) ◽  
pp. 116-121
Author(s):  
Nikita A. Pen’kov ◽  
◽  
Oleg A. Sidorkin ◽  
Sergey Yu. Zhachkin ◽  
Anatoliy I. Zavrazhnov ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Current Density ◽  
Hydraulic Drive ◽  
Research Purpose ◽  
Working Fluid ◽  
Agricultural Machinery ◽  
Servo Valve ◽  
Contact Points ◽  
Drive Systems

One of the most common reasons for the failure of hydraulic drive systems for agricultural machinery is the working fluid leak in the contact points of the rubbing surfaces of hydraulic blocks. The application of composite coatings based on chromium on the contacting surfaces allows you to restore the defect in the shape of the part caused by wear, as well as reduce the friction coefficient at the contact points, which positively affects the wear resistance of the part. (Research purpose) The research purpose is in developing technologies for restoring parts of agricultural machinery with predetermined operational properties. (Materials and methods) A servo valve, widely used in various hydraulic drive systems, was used as an experimental sample. Its working surface was restored with a composite coating applied by electroplating to increase the wear resistance of the servo valve. (Results and discussion) Authors conducted a series of direct measurements under the same conditions. The article presents the de-pendence of the microhardness on the parameters of the electrolysis mode and the thickness of the applied coating using the method of least squares. The nature of changes in microhardness and residual stresses was evaluated to determine the quality of the coatings. The article presents the dependences of these indicators on various control parameters (current density, temperature, tool pressure). The equations of the regression of the main qualitative and accuracy characteristics of the parts were deter-mined using the apparatus of the theory of experimental planning. (Conclusions) The article presents the method for predicting coatings of a given quality, taking into ac-count the influence of the current density and the temperature of the electrolyte during electrolysis on the nature of the precipitation obtained. The influence of the tool pressure on the depth of deformation of the formed layers was estimated. This approach allows us to evaluate the nature of the stress distribution in the formed coating and the quality of the restored parts.

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

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.

scholarly journals ENERGY-EFFICIENT TECHNICAL SOLUTIONS FOR THE OPERATIONAL CHARACTERISTICS OF THE HYDRAULIC DRIVE OF THE TRACTOR

2021 ◽  
Author(s):  
R.V. Yudin ◽  
◽  
R.N. Puzakov ◽  
Keyword(s):  
Energy Saving ◽  
Energy Efficient ◽  
Hydraulic System ◽  
Hydraulic Drive ◽  
Working Fluid ◽  
Uneven Terrain ◽  
Operational Characteristics ◽  
High Dynamic ◽  
Hydraulic Accumulator ◽  
Technical Solutions

During the movement of the tractor on the uneven terrain, there are fluctuations that cause jumps of the working fluid in the hydraulic system and high dynamic loads. The solution to this problem is the use of an energy-saving hydraulic drive with a hydraulic accumulator and a system of aggregates this leads to increased efficiency and increased productivity of skidding grippers. A mathematical model of working processes with an energy-saving hydraulic drive is compiled.

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

2019 ◽  
Vol 19 (3) ◽  
pp. 242-249 ◽  
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.

Land-Saving Mode of Congo (Brazzaville) Highway One (Phase II)

2012 ◽  
Vol 256-259 ◽  
pp. 1832-1836
Author(s):  
Jing Shi ◽  
Jin Hua Tan ◽  
Nian Zhou
Keyword(s):  
Service Life ◽  
Literature Review ◽  
Traffic Flow ◽  
Phase Ii ◽  
Road Construction ◽  
Cultivated Land ◽  
Turning Radius ◽  
Saving Mode ◽  
Congo Brazzaville ◽  
Land Saving

Plenty of cultivated land has been used for highway construction. Thus Land-saving mode in road construction has drawn more and more attentions. However, inappropriate land-saving mode may result in some kinds of risks during highway's service life. Based on road risk, this paper discusses land-saving mode of Congo (Brazzaville) Highway One (Phase Ⅱ), trying to reach the balance between the two after accomplishing literature review and analyzing the prediction of traffic flow. The result shows that, the project should choose the mode such as proper construction scale and high bridge & tunnel ratio, rather than small turning radius and low roadbed.

Hydraulics

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.

Stainless Steels as Erosion Resistant Materials for Hydraulic Machines

2017 ◽  
Vol 750 ◽  
pp. 75-79
Author(s):  
Brandusa Ghiban ◽  
Carmen Anca Safta ◽  
Vlad Motoiu
Keyword(s):  
Steam Turbine ◽  
Geothermal Energy ◽  
Electric Energy ◽  
Heat Energy ◽  
Hydrodynamic Cavitation ◽  
Metallic Surface ◽  
Working Fluid ◽  
Corrosion Mechanism ◽  
Hydraulic Machines ◽  
Abrasive Erosion

The corrosion phenomena lead to serious modifications in the structure of metallic materials from which are manufactured the important active components of hydraulic machines. There are two important types of corrosion: cavitation and silt erosion (abrasive erosion), that are specific to machines which are producing energy [1, 2, 3]. As a corrosion mechanism, in hydrodynamic cavitation [4, 5], when cavitation bubbles implode on the solid surface of hydraulic machine component, the local pressure developed is high and can exceed the fatigue strength, yield point or compression strength of the material. Cavitation phenomenon can be produced in different ways. Four types of cavitation are described in the literature, looking for the method of producing, [6]: hydrodynamic cavitation, particle cavitation, acoustic cavitation, and optic cavitation. Abrasive erosion is the gradual degradation of a structure under the action of solid particles suspended in the working fluid. Impact and sliding erosion are the main categories of abrasive erosion approached in the literature by considering the mechanisms of which the abrasive particles act on the metallic surface, [2]. In the last decades the abrasive erosion phenomenon became a serious problem for the efficient operation of power plants, for instance in hydropower plants [7, 8]. Geothermal energy is the heat energy of the earth given by capturing the springs of heat water. In Romania the geothermal energy is used only for heating because the water has a low temperature and cannot be used to produce electric energy, only heat energy. So, although Romania is the third highest potential geothermal in Europe, practically electric energy from geothermal resource has a low thermal potential, [9]. A steam turbine is working at high rotational speed, high temperatures and using the working fluid which could be steam or wet steam. The working fluid is composed of corrosive chemicals with an aggressive pH. For this reason the common problems of the geothermal steam turbine failures are given by fractures of the blades (rotor blades or stator blades).

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