scholarly journals Performance Features of Tooth Gearing in Gear Hydraulic Machines

2021 ◽  
Vol 24 (2) ◽  
pp. 84-91
Author(s):  
Yuri V. Kuleshkov ◽  
Timofey V. Rudenko ◽  
Mikhailo V. Krasota ◽  
Miroslav Bošanský ◽  
František Tóth
Keyword(s):  
Mathematical Models ◽  
Relative Slip ◽  
Hydraulic Oil ◽  
Involute Gear ◽  
Hydraulic Machines ◽  
Hydraulic Motors ◽  
Torque Pulsations ◽  
Further Development

Abstract The paper presented determines that the rotation velocities of gears and radii connecting the axes of rotation of the gears with the point of their teeth gearing are not equal with each other. It is explained by the relative slip of involute gear profiles during their rolling. This phenomenon will become a prerequisite for further development of creation of mathematical models in the context of theory of gear hydraulic machines. The models can explain a number of specific phenomena in the operation of gear hydraulic machines, such as pressure and input pulsations, dynamics of hydraulic oil in the cut-off plane, combined torque pulsations in gear hydraulic motors and others.

scholarly journals The Influence of the form Error after Rotor Manufacturing on the Output Characteristics of an Orbital Hydraulic Motor

2018 ◽  
Vol 7 (4.3) ◽  
pp. 1 ◽  
Author(s):  
Anatolii Panchenko ◽  
Angela Voloshina ◽  
Irina Milaeva ◽  
Igor Panchenko ◽  
Olena Titova ◽  
...  
Keyword(s):  
Mathematical Models ◽  
Hydraulic Motor ◽  
Form Error ◽  
Form Errors ◽  
Hydraulic Machines ◽  
Hydraulic Motors ◽  
Negative Effect ◽  
Output Characteristics ◽  
Internal Rotor ◽  
The Relationship

The technology of rotors manufacturing for orbital hydraulic motors causes a certain form error of the gear surface. This leads to oscillations of the diametrical gap between the rotors. Such oscillations have a negative effect on the change in the output characteristics of the orbital motor. The previous studies on the issue consider the interaction between the rotors of orbital hydraulic machines as a gapless (theoretical) connection. The authors do not take into account that between the rotors of the orbital hydraulic motor, there is no rigid kinematic connection. This allows the internal rotor to move randomly within the diametrical gap (self-aligning). The study led to the development of the mathematical models that describe the relationship between the design features of the rotors and the output characteristics of an orbital hydraulic motor. To simulate the oscillation of the diametrical gap, the limiting deviations for the form error of the rotor gear surfaces have been substantiated. Investigations revealed that fluctuations in the form error of the rotor gear surface have a significant effect on the variation of the diametrical gap. The limiting deviations in the form errors of the gear surface manufacturing enabled to eliminate the oscillation of the diametrical gap and to ensure stability of the output characteristics for the orbital hydraulic motor. 

scholarly journals Analysis of forest soil acidification processes in the area of NP 'Kopaonik'

2009 ◽  
pp. 95-110 ◽  
Author(s):  
Ratko Kadovic ◽  
Snezana Belanovic ◽  
Milan Knezevic ◽  
Jelena Belojica ◽  
Jasmina Knezevic
Keyword(s):  
Mathematical Models ◽  
Forest Soil ◽  
Soil Acidification ◽  
Critical Loads ◽  
Forest Ecosystems ◽  
Podzolic Soil ◽  
The Subject ◽  
Further Development

In the last two decades, S and N critical loads have been used as indicators of ecosystem sustainability to soil acidification. The effect of acidification on the soil in forest ecosystems and their further development was the subject of numerous studies, based on which several mathematical models were developed. This paper presents the results of the analysis of acidification processes in brown podzolic soil on granodiorites in the stands of spruce and spruce and fir in the area of NP 'Kopaonik'. Critical loads of sulphur and nitrogen in these soils are presented using VSD model.

A study of an elbow mechanism generated by a conical cutter

2007 ◽  
Vol 221 (6) ◽  
pp. 727-738 ◽  
Author(s):  
S-C Yang
Keyword(s):  
Mathematical Model ◽  
Mathematical Models ◽  
Von Mises Stress ◽  
Tooth Contact Analysis ◽  
Rapid Prototyping And Manufacturing ◽  
Von Mises ◽  
Design And Manufacture ◽  
The Mathematical Model ◽  
Further Development ◽  
Kinematic Errors

This paper presents a method for determining the mathematical model of an elbow mechanism with a convex tooth and a concave tooth. Based on this method, the mathematical model presents the meshing principles of a conical cutter meshed with a tooth that is either convex or concave. Using the developed mathematical models and the tooth contact analysis, kinematic errors are investigated according to the obtained geometric modelling of the designed gear meshing when assembly errors are present. The influence of misalignment on kinematic errors has been investigated. The goal of the current study is to investigate von-Mises stress for three teeth contact pairs. A structural load is assumed to act on a gear of the proposed mechanism. The von-Mises of the proposed gear is determined. The conical cutter used in the design and manufacture of the convex and concave gear is shown. For example, the proposed mechanism with a transmission ratio of 3:2 was determined with the aid of the proposed mathematical model. Using rapid prototyping and manufacturing technology, an elbow mechanism with a convex gear, a concave gear and a frame was designed. The RP primitives provide an actual full-size physical model that can be analysed and used for further development. Results from these mathematical models are applicable to the design of an elbow mechanism.

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 Mathematical models in nursing research

2020 ◽  
Vol 9 (4) ◽  
Author(s):  
Teresa Rea ◽  
Assunta Guillari ◽  
Consolato Sergi ◽  
Nicola Serra
Keyword(s):  
Artificial Intelligence ◽  
Big Data ◽  
Tumor Growth ◽  
Mathematical Models ◽  
Strong Interaction ◽  
Nursing Research ◽  
Experimental Tumor ◽  
Daily Work ◽  
Further Development

This paper discusses the use of advanced mathematical tools in nursing research, such as mathematical models used in medicine for description and prediction of experimental tumor growth. They are rarely used in nursing research, but fortunately in the last decade, their use is increased, particularly due to the artificial intelligence and Big Data, with great benefits for further development of nursing. Therefore, a strong interaction between nurses and mathematicians is needed to improve nursing research, and consequently the nurses performance in daily work.

Mathematical Model for Multifacet Drills

1983 ◽  
Vol 105 (3) ◽  
pp. 173-182 ◽  
Author(s):  
S. M. Wu ◽  
J. M. Shen
Keyword(s):  
Mathematical Model ◽  
Mathematical Models ◽  
Grinding Process ◽  
Five Axis ◽  
First Time ◽  
Further Development

Mathematical models are developed for the first time to describe a multifacet drill (MFD) point geometry, which has been evolved by experiments since 1953 in Peking. A precise grinding process has been adopted on a CNC five-axis drill grinder using the model. A highly repetitive MFD has been reproduced to ensure its further development and applications.

Methodological Aspects of Determining Thrust of Irrotational Air-Breathing Jet Engines in Bench and Flight Tests

2019 ◽  
pp. 86-97
Author(s):  
V.L. Semenov ◽  
V.Yu. Aleksandrov ◽  
A.N. Prokhorov ◽  
K.Yu. Arefyev ◽  
S.V. Kruchkov
Keyword(s):  
Mathematical Models ◽  
High Speed ◽  
Specific Impulse ◽  
Jet Engines ◽  
Flight Tests ◽  
Air Breathing ◽  
Internal Parameters ◽  
Thrust Characteristics ◽  
Methodological Aspects ◽  
Further Development

This article examines methodological aspects of the indirect calculation of thrust characteristics of irrotational air-breathing jet engines using telemetry data that can be obtained during high-speed aircraft flight tests. Specific features of determining thrust characteristics during bench and flight tests are described. Mathematical models are developed for data analysis and calculation of the thrust and the specific impulse of an irrotational air-breathing jet engine by internal parameters, as well as its effective thrust in integration with a high-speed aircraft. The proposed approaches are tested, and the developed mathematical models are validated according to the results of experimental bench tests of the thrust characteristics of irrotational air-breathing jet engines in integration with a model fuselage of a high-speed aircraft. Satisfactory convergence of the results of indirect and direct (experimental) force measurements is shown. The data obtained can be used for further development of the method and analysis of bench and flight tests of aircraft with irrotational air-breathing jet engines.

Aiding Design Decision Making: Adapting Mathematical Paradigms to Fit Designers’ Actual Needs

2008 ◽  
Author(s):  
C. C. Hayes ◽  
F. Akhavi
Keyword(s):  
Decision Making ◽  
Mathematical Models ◽  
Ethnographic Study ◽  
Design Decision ◽  
Quality Cost ◽  
Design Alternatives ◽  
Selection Decisions ◽  
Product Decision ◽  
Further Development

When designing products, designers compare complex alternatives and select one or more for further development. The quality of these selection decisions directly impacts the quality, cost and safety of the final product. Decision theoretic approaches for making systematic comparisons might help in this process, yet designers do not tend to use them. The goals of this work are to begin understanding why, and to identify future questions that may lead to solutions. This paper summarizes the results of two studies, 1) an ethnographic study of working designers in which their actual practices and needs were observed during decision making, and 2) a laboratory study in which designers were asked to use mathematical models to compare and select design alternatives. Based on these studies, we conclude that the mathematical models, as formulated, are not well suited to designers’ needs. We propose a research agenda that may lead to new approaches combining decision theoretic and user-centered methods to create tools that the average designer will be willing to use.

A Consideration on the Behavior of Hydraulic Pressure Ripples in Relation to Hydraulic Oil Temperature

2015 ◽  
Author(s):  
Shuichi Nakagawa ◽  
Takayoshi Ichiyanagi ◽  
Takao Nishiumi
Keyword(s):  
Thermal Properties ◽  
Physical Properties ◽  
Mathematical Models ◽  
Bulk Modulus ◽  
Temperature Change ◽  
Speed Of Sound ◽  
Thermal Characteristics ◽  
Hydraulic Pressure ◽  
Hydraulic Oil ◽  
Pressure Ripples

It is well known that hydraulic noise can change as a system warms up. That change can be a factor for misperception of mechanical failure, because noise can play an important role as a signal that indicates abnormal operation. It is therefore important to understand the behavior of hydraulic pressure ripples that are a source of hydraulic noise in operating conditions, and how they change in relation to the temperature of the hydraulic oil. This study has investigated the ripple behavior that results from temperature change in simple hydraulic systems, using mathematical models that took thermal properties into account. Physical properties of the oil and the speed of sound in the oil have been defined as temperature-related variables in the mathematical models. The physical properties that should be used in the mathematical models have been obtained directly from the oil manufacturer. In contrast, the speed of sound in the oil has to be obtained from the isentropic tangent bulk modulus of the oil in an actual operating condition. That has been determined from the specific volume ratio of entrained air to the oil and the isentropic tangent bulk modulus of the only oil. The thermal properties of the speed of sound in the oil have been determined from the thermal characteristics of these variables, and it has been found that the speed of sound in the oil decreases with a rise in the oil temperature. The mathematical models of pressure ripples have shown that there were three distinct phenomena resulting from the temperature change of the oil. The first is the change of wavelength. The second is the spatial dependence of the thermal characteristics of the pressure ripples. The third is the difference of the thermal characteristics of the pressure amplitude at the peak in spatial modes. These changes that result from the temperature variation tend to be large at higher frequency.

scholarly journals Management of the Development and Implementation of New Generation Technologies

2020 ◽  
Vol 11 (1) ◽  
pp. 12-28 ◽  
Author(s):  
N. I. Komkov ◽  
V. V. Sutyagin
Keyword(s):  
Decision Making ◽  
Mathematical Models ◽  
New Technologies ◽  
Technology Development ◽  
Full Life Cycle ◽  
Russian Economy ◽  
Innovative Solutions ◽  
Innovative Products ◽  
New Generation ◽  
Further Development

Purpose: to justification of the need to develop new-generation domestic technologies that ensure the competitiveness and stability of the Russian economy to external challenges. Using the laws of accelerated development of various systems, objects and processes of the material world will allow us to construct a mechanism for analysis, decision-making and management of the justification, development and implementation of new generation technologies.Methods: the research method is based on the generalization of forecasting the accelerated development of various processes under the conditions of growth restrictions, methods for constructing targeted information-logic models, decision-making methods for justifying the costs of upgrading one-generation technology options and analyzing domestic and foreign technology development experience new generation.Results: within the space of creation and development of new generation technologies, in accordance with the well-known concept of the full life cycle, the process of development and implementation of new generation technologies in the form of a logistic curve has been specified. The solution to the problem of managing the creation of new generation technologies is presented as the fastest possible implementation of projects to search for innovative solutions that meet the requirements of competitiveness. Mathematical models of the formulated problem are considered. Examples of practical tasks for managing the development and development of new generation technologies are given.Conclusions and Relevance: the dynamics of development and the economic conditions for the transition to technology modernization are determined by the need for further development of new generation technologies in the interests of full use of the innovative potential of this generation. Information-logical and mathematical models have been developed for making decisions on managing the justification of the necessary resources for the implementation of projects in the full cycle during the transition from innovative solutions to new technologies and innovative products.

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