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Date submitted2018-08-30
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Date accepted2018-10-26
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Date published2019-02-22
Study of bearing units wear resistance of engines career dump trucks, working in fretting corrosion conditions
- Authors:
- Ju. Olt
- V. V. Maksarov
- V. A. Krasnyy
The occurrence of fretting corrosion on nominally fixed surfaces of high-loaded parts of mining machines and mechanisms is considered. Examples of wear and damage of critical parts, bearing assemblies of engines of dump trucks in fretting conditions are given. The mechanisms of fretting corrosion when using wear-resistant coatings are considered. It is noted that when choosing protective thin-layer coatings that provide an increase in the fretting-resistance of surfaces of tightly contacting parts, it is necessary to take into account both their wear resistance and the ability to resist shear. At the same time, the thickness of such coatings allows preserving, during operation, those provided during the assembly of the tension, without disturbing the maintainability of the nodes. The results of research of fretting wear of a number of coatings on a special installation are given. The mechanisms of wear of a number of thin-layer coatings based on friction-mechanical brazing, polymer fluorocarbon composition, solid lubricant coating using scanning electron microscopy were studied. Recommendations on the use of the studied thin-layer coatings for high-loaded parts of mining machines operating in fretting corrosion conditions have been developed. The aim of the work was to study the effect of a number of thin-layer coatings on the wear of highly loaded connections of the mechanisms of mining machines, in particular bearing assemblies of quarry dump trucks operating under fretting corrosion conditions.
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Date submitted2017-08-25
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Date accepted2017-11-17
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Date published2018-02-22
Improved estimation of open pit excavator capacity
- Authors:
- S. N. Zharikov
The paper addresses issues related to estimation of operational time for open pit excavators during truck loading operations. The author analyzes the method of annual capacity estimation and highlights disagreements in different ways of operational time logging. Recommendations are offered concerning estimation of excavator capacity taking into account its repair cycle. The paper contains an analysis of the cyclical nature of various types of maintenance in the interval between capital repairs as a function of operational time. Guidelines are proposed that allow to calculate annual production days of the excavator with regards to the repair cycle and adjusted utilization coefficient throughout the shift. It has been established that decreasing the coefficient of excavator utilization throughout the shift and more precise logging of annual work days lead to a slower decrease in estimated machine capacity than the one described in the reference literature. According to the suggested method, estimated excavator capacity is more than 23 % higher than the value stated in the reference literature.
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Date submitted2015-08-24
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Date accepted2015-10-16
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Date published2016-04-22
Ways to ensure reliability, safety and efficiency of the costruction and installation works when buildings and structures erecting by stabilizing process of the rocking cargo suspension
- Authors:
- L. A. Goldobina
- P. S. Orlov
Nondestructive optical methods for measuring of the «thick» films thickness of the order of 0,001-1,00 mm are analyzed. It is shown that using the laser beam radiation and modern optical and electronic schemes possible to decrease the time of single measurement to 1ms and less at the measuring frequency of 10-50 hz. The possibility of measuring thickness and spreading coefficient and evaporation kinetics of liquid films is demonstrated. A new computer method of the data processing aimed to determine the film thickness from the angle dependence of the laser beam reflection coefficient by the film is offered. The offered procedure and the experimental technique realizing it permits to decrease the thickness determination uncertainty to the order of ten.
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Date submitted1953-07-26
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Date accepted1953-09-20
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Date published1954-12-04
Пути улучшения режима работы врубовых машин на шахтах, добывающих горючие сланцы
- Authors:
- Unknown
За последние годы добыча горючих сланцев в Советском Союзе значительно возросла. Темпы развития сланцедобывающей промышленности значительно превосходят темпы развития угольной промышленности. В директивах XIX съезда КПСС по пятому пятилетнему плану развития народного хозяйства СССР на 1951—1955 гг. указано: «. .увеличить производство сланцев в 2,3 раза, особенно в Эстонской ССР». Такое бурное развитие сланцедобывающей промышленности возможно лишь на базе высшей техники. Сланцевые шахты оснащаются современными мощными машинами и механизмами. Однако используется эта техника еще недостаточно эффективно, что объясняется, главным образом, недостаточной изученностью процессов работы горных машин в специфических условиях сланцевых шахт. Имеется большое число исследований по резанию углей, но совершенно отсутствуют какие-либо работы по резанию горючих сланцев. Приводимые в настоящей статье материалы основаны на экспериментальных исследованиях зарубки по горючим сланцам. Исследования проводились в течение нескольких лет на шахтах Ленинградсланца и в лабораториях Ленинградского горного института. Опыты производились без самопишущих инструментов, применялся лишь комплект малогабаритных электроизмерительных приборов, что несколько уменьшило точность отсчетов (в пределах 5—7%).
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Date submitted1949-07-17
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Date accepted1949-09-28
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Date published1949-07-29
About the operating mode of bulk handling mechanisms
- Authors:
- Ya. B. Kalnitskii
The last two decades have been a period of intense and continuous work for the coal industry of the USSR in the field of solving the problem of complex-mechanized coal mining and, above all, the problem of mechanization of coal loading in working faces. In the development of technical methods and the design of new machines for this extremely important purpose, Soviet mining science and technology have achieved significant success and occupy a leading place. Our designers and inventors have an indisputable priority in the matter of creating loading machines and longwall mining combines, which are the first in world practice to be produced and used in series. Based on the accumulated experience in the design and operation of loading mechanisms in our country, it became possible to formulate and successfully resolve in the fourth five-year plan the most important national economic task: "...to mechanize labor-intensive processes in the coal industry in every possible way, in particular to ensure the widespread implementation of work on the mechanization of coal loading...". Both specialized bulk machines and bulk units of mining combines were designed in the Soviet Union according to a wide variety of schemes. Initially, designers and machine builders sought to create machines with constant mechanical characteristics, designed for use in any mining conditions. In our coal industry, the desire for universality of mining mechanisms determined persistent attempts to build a machine suitable for any conditions of cleaning excavation.
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Date submitted1948-07-11
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Date accepted1948-09-13
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Date published1949-11-04
On the influence of the cost of transport on the floor crosscuts on the most advantageous dimensions of the mine field
- Authors:
- O. B. Bokii
This article is devoted to the assessment of the impact of the cost of hauling minerals along floor crosscuts on the most advantageous longwall dimensions of the mine field of a vertical shaft opening a suite of steeply dipping seams, determined by the method of L. D. Shevyakov. The cost of hauling minerals along crosscuts during the development of a suite of steeply dipping seams by a vertical shaft with floor crosscuts increases with the increase in the number of floors in the mine field and decreases the most advantageous number of floors against the values given by L. D. Shevyakov's formulas derived without taking this factor into account. In exceptional cases (location of the mine outside the suite with a small angle of dip of the seams), the number of floors determined without taking into account the cost of transport along floor crosscuts may exceed their most advantageous number by 50% or more.