SELECTION OF THE SHAPE OF THE LOAD CHARACTERISTICS OF ADAPTIVE FRICTION COUPLINGS WITH SEPARATE POWER CLOSURE

Author(s):  
D. A. Ramazanov ◽  

It is established that in practice it is possible to use adaptive friction clutches of the second generation with a separate power circuit, having two different forms of load characteristics: in the form of a curve monotonically increasing in the range of values of the coefficient of friction; in the form of a curve having a maximum point within the specified interval, excluding its boundary values. It is shown that the choice of the type of adaptive friction clutch and its technical and operational characteristics are mainly influenced by the value of the nominal torque and the specified maximum mass of the drive. Three main requirements for adaptive friction clutches operating as part of the machine drive are formulated.

Author(s):  
D.A. Ramazanov ◽  

The main provisions of the method for selecting the form of the load characteristic of the AFM with a separate power circuit are formulated. The method involves taking into account the nominal load, the total mass of the drive, the value of the gain of the adaptive friction clutch with a separate power circuit and the accuracy of its operation, as well as recommendations for the choice of the second design version of the clutch. The choice of the type of adaptive friction clutch, taking into account the load characteristics, is based on the different load capacity and accuracy of operation, which correspond to these forms.


Author(s):  
V. E. Zinoviev ◽  

The generalized schematic diagram and mathematical model of the adaptive friction clutch of the second generation with a separate power circuit, designed for the use of technical and operational characteristics, are synthesized. Three variants of the circuit of separate power circuit in the coupling are established and their mathematical models are developed. The limits of maximum values of parameters allowing to optimize accuracy of operation of the coupling are established.


2019 ◽  
Vol 13 (3) ◽  
pp. 235-240
Author(s):  
Iryna Solonenko

The development of road network infrastructure is an important component of the economic development of the European Union. Updating of the road network contributes to the integration of the economies of countries into a coherent whole. The road network provides the free movement of citizens, the movement of goods and the effective implementation of various services. The increase in the length of the road network leads to an increase in the financial and material costs necessary to ensure its maintenance and repair. One of the ways to reduce costs is by strengthening the physic-mechanical and operational characteristics of the pavement due to the widespread use of cement concrete. The quality of the pavement of cement concrete depends largely on the rational selection of its composition. This allows a significant increase in the durability of road pavement. The purpose of the research was: the development of recommendations for the rational selection of the composition of the road pavement material of cement concrete, aimed at upgrading longevity, and taking into account its frost resistance grade. According to the goal, the following tasks were developed: the analyses of the climatic zones in which the road network of the European Union is located; the development of a research plan, a selection of the response function and influence factors; the study of physico-mechanical and operational characteristics of the researched material of road pavement; on the basis of the obtained data, the calculation of the complex of experimental-statistical models, which describe the physico-mechanical and operational characteristics of the road pavement material; on the basis of experimental statistical models, a method was proposed for selecting the rational compositions of the cement concrete pavement road material depending on the conditions of its application. The results presented in the article can be used in engineering and scientific practice for the selection of road pavement from cement concrete for highways.


Author(s):  
E. M. Evans ◽  
J. Whittle

This paper is intended to demonstrate that designers of wet clutches for power transmission can obtain the optimum friction characteristics for specific applications by considering the interaction between friction materials and lubricants. A friction clutch plate rig is described and the friction results obtained are presented. It is shown that a wide variation of coefficients of friction and frictional characteristics in wet friction clutches can be obtained by changing the oils and friction materials. In particular the coefficient of friction is dependent upon (1) the oil, (2) the materials of the sliding surfaces, (3) sliding speed, and (4) temperature. It is also shown that the coefficient of friction is affected by ( a) refining treatment given to the oil, ( b) different base oils, and ( c) additives.


2006 ◽  
Vol 519-521 ◽  
pp. 949-954 ◽  
Author(s):  
Beong Bok Hwang ◽  
J.H. Shim ◽  
Jung Min Seo ◽  
H.S. Koo ◽  
J.H. Ok ◽  
...  

This paper is concerned with the analysis of the forming load characteristics of a forward-backward can extrusion in both combined and sequence operation. A commercially available finite element program, which is coded in the rigid-plastic finite element method, has been employed to investigate the forming load characteristics. AA 2024 aluminum alloy is selected as a model material. The analysis in the present study is extended to the selection of press frame capacity for producing efficiently final product at low cost. The possible extrusion processes to shape a forward-backward can component with different outer diameters are categorized to estimate quantitatively the force requirement for forming forward-backward can part, forming energy, and maximum pressure exerted on the die-material interfaces, respectively. The categorized processes are composed of combined and/or some basic extrusion processes such as sequence operation. Based on the simulation results about forming load characteristics, the frame capacity of a mechanical press of crank-drive type suitable for a selected process could be determined along with securing the load capacity and with considering productivity. In addition, it is suggested that different load capacities be selected for different dimensions of a part such as wall thickness in forward direction and etc. It is concluded quantitatively from the simulation results that the combined operation is superior to sequence operation in terms of relatively low forming load and thus it leads to low cost for forming equipments. However, it is also known from the simulation results that the precise control of dimensional accuracy is not so easy in combined operation. The results in this paper could be a good reference for analysis of forming process for complex parts and selection of proper frame capacity of a mechanical press to achieve low production cost and thus high productivity.


Author(s):  
V. E Zinoviev ◽  

For the third variant of the adaptive friction clutch with a separate force closure, the boundaries of the change in the value of the feedback gain are determined, within which the clutch has the highest accuracy of operation, if its load characteristic is realized in the form of a curve monotonically increasing in the range of the friction coefficient values. A variant of separate power closure is developed, which provides for the introduction of an additional spring into the clutch design in the closure node of the thorn pairs of the main friction group.


2014 ◽  
Vol 40 (5) ◽  
pp. 543-551 ◽  
Author(s):  
Marcelino Santos-Neto ◽  
Mellina Yamamura ◽  
Maria Concebida da Cunha Garcia ◽  
Marcela Paschoal Popolin ◽  
Tatiane Ramos dos Santos Silveira ◽  
...  

OBJECTIVE: To characterize deaths from pulmonary tuberculosis, according to sociodemographic and operational variables, in the city of São Luís, Brazil, and to describe their spatial distribution. METHODS: This was an exploratory ecological study based on secondary data from death certificates, obtained from the Brazilian Mortality Database, related to deaths from pulmonary tuberculosis. We included all deaths attributed to pulmonary tuberculosis that occurred in the urban area of São Luís between 2008 and 2012. We performed univariate and bivariate analyses of the sociodemographic and operational variables of the deaths investigated, as well as evaluating the spatial distribution of the events by kernel density estimation. RESULTS: During the study period, there were 193 deaths from pulmonary tuberculosis in São Luís. The median age of the affected individuals was 52 years. Of the 193 individuals who died, 142 (73.60%) were male, 133 (68.91%) were Mulatto, 102 (53.13%) were single, and 64 (33.16%) had completed middle school. There was a significant positive association between not having received medical care prior to death and an autopsy having been performed (p = 0.001). A thematic map by density of points showed that the spatial distribution of those deaths was heterogeneous and that the density was as high as 8.12 deaths/km2. CONCLUSIONS: The sociodemographic and operational characteristics of the deaths from pulmonary tuberculosis evaluated in this study, as well as the identification of priority areas for control and surveillance of the disease, could promote public health policies aimed at reducing health inequities, allowing the optimization of resources, as well as informing decisions regarding the selection of strategies and specific interventions targeting the most vulnerable populations.


Wood Research ◽  
2021 ◽  
Vol 66 (5) ◽  
pp. 789-805
Author(s):  
MATEUSZ KUKLA ◽  
ŁUKASZ WARGUŁA ◽  
ALEKSANDRA BISZCZANIK

In order to improve the power selection of the drive unit for the shredding machines,theauthors determine the values of friction coefficients used in the cutting force models. These values consider the friction between steel and such wood-based materials as chipboard, MDF and OSB. The tests concern laminated and non-laminated external surfaces and surfaces subjected to cutting processes. The value of the coefficient of friction for the tested materials is in the range: for the static coefficient of friction 0.77-0.33, and for the kinetic coefficient of friction 0.68-0.25. The highest values of the static and kinematic coefficient of friction were recorded for MDF (non-laminated external surface) and they were equal respectively: 0.77 and 0.68. In turn, thesmallest values of the discussed coefficients were recorded for chipboard (laminated external wood-base surface), which were at the level of 0.33 and 0.25, resp.


2015 ◽  
Vol 792 ◽  
pp. 529-535
Author(s):  
Stanislav V. Makarov ◽  
Alexander Vladimirovish Myatez ◽  
Vitali D. Suslyakov

The article presents the research aimed at improving the efficiency of the diesel engines running. The advantages and disadvantages of the existing systems of the starter starting systems of diesel locomotives are considered. Brainstorming ideas on the issue of the calculation and selection of the alternative circuitry power circuit pulse converter starting system of diesel engines are described in the paper. An example of calculating the regulating characteristics of the pulse converter and the efficiency of the proposed circuit design is reported.


1973 ◽  
Vol 95 (4) ◽  
pp. 1123-1130 ◽  
Author(s):  
R. Kasuba ◽  
E. I. Radzimovsky

Feasibility of a multi-purpose testing machine for research studies in gearing has been demonstrated with construction of a unique gear testing machine with a differential planetary gear drive. This machine was used in such interdependent studies as determination of instantaneous gear tooth engagement loads, minimum film thicknesses, and gear efficiencies. With minimal structural and mechanical modifications, this gear research machine can be used for studies of surface durability, thermal distribution in gear meshing zones, and effects of variable torques and torsional oscillations on performance of gearing. Most of these studies could be conducted simultaneously. Upon selection of appropriate gear ratios, this machine was operated either with one or two stationary gears. Presence of stationary gears simplified greatly the measurement techniques and increased the reliability of tests. This machine can accommodate spur, helical or any special type of gearing. Design and operational characteristics of this machine, as well as a short summary of research projects performed on this machine, are presented in this paper.


Sign in / Sign up

Export Citation Format

Share Document