No abstract

The article considers kinematic, force and parametric characteristics of an open cylindrical gear train of the rotation mechanism of an excavator as sources of oscillations of mechanisms with a tooth frequency. The author builds a two-mass dynamic model with an internal perturbation in the form of a variable gear ratio and taking damping into account. The paper shows that the main perturbations can be the difference between the basic pitches of the gear and the wheel and the error of the involute profile of the side surface of the teeth. These errors occur during the manufacture of a gear pair and due to wear of the teeth. The errors in the relative position of the gear and wheel teeth, the variable tooth hardness with an overlap ratio greater than one, friction in the engagement for open gear train of a large module and manufactured by 8 … 9 degrees of accuracy, play a significantly smaller role in the excitation of oscillations. The effect of the considered sources of oscillations should be taken into account in the resonant modes of the mechanism operation.

Abstract. Ball mills for fine grinding cement clinker and additives are widely used around the world. To improve the efficiency of a ball grinding the ball mills are transferred in closed circuit with air-separators of various designs. In the article the analysis of existing grinding circuits on the basis of closed circuit ball mills made. Introduced a summary measure that allows to evaluate the performance of the grinding system according to various criterias. The conclusion about the prospects of data systems grinding when grinding to ordinary cement, in comparison with the grinding systems based on other principles of grinding.

The problem of limiting the standard-size range of drive mechanisms for hydraulic excavators and self-propelled jib cranes with a wide unification of their elements is considered. This approach allows to increase the serialization of products to reduce costs in the design and production, increases the durability of machines and reduces the time of development of new equipment.The analysis of the production of domestic excavators and cranes is carried out. It is presented in a tabular version and a sequence of logical steps to provide a systematic approach to the development of rational designs of hydraulic excavators and cranes. The analysis showed that it is advisable to carry out unification on the modular principle of the formation of some units and, first of all, of slewing mechanisms of these machines. The technique of unification of turning mechanisms and winches of excavators and cranes based on unified planetary hydromechanical block modules is proposed. Creating hydraulic excavators and cranes with unified planetary hydromechanical mechanisms allows you to reduce operating costs and improve the quality of drive mechanisms for excavators and cranes, reducing the cost and complexity of manufacturing. Unification on a modular principle and the subsequent cooperation of parts, assemblies and units allows expanding opportunities to increase production volumes, provides interspecific unification of their basic elements.

Аннотация. Рассмотрена проблема ограничения типоразмерного ряда механизмов привода гравитационных бетоносмесителей на основе широкой унификации их комплектующих элементов. Проведен анализ методик унификации технических систем, который представлен последовательностью логических шагов, обеспечивающих системный подход к разработке рациональных конструкций бетоносмесителей и комплектующих их элементов. Предложена методика унификации механизмов привода гравитационных бетоносмесителей на базе унифицированных планетарных блок-модулей и методики выбора рациональных кинематических схем и конструкции смесителей, позволяющих получить широкий диапазон передаточных отношений и оптимальных скоростей вращения рабочих органов бетоносмесителей. Рост потребности в бетоносмесителях стимулирует процесс совершенствования конструкции и механизмов привода, но возрастает и многообразие видов привода. Поэтому создание бетоносмесителей с унифицированными планетарными модульными механизмами привода позволяет снизить затраты при эксплуатации и повысить надежность и качество смесителей.