Ensuring the reliability and performance criterias of crankshafts

The issues of efficiency improvement of manufacturing crankshafts in order to ensure their reliability and performance criteria are the priorities in modern production of internal combustion engines. Using the capabilities of modern special grinding machines can improve the quality of machining and obtain the necessary running characteristics of crankshafts. In work the questions connected with development of a method of calculation of rigidity of crankshafts for increase of accuracy of their machining, reliability and performance criteria’s are considered. Based on the proposed methodology, numerical calculations have performed and the possibility of determining the deflections and crankshafts rigidity in any section have been justified. The original construction of the following grinding steady rest for CNC grinding machines specified for machining the crankshaft main bearing journal and connecting rod journal is proposed. The construction design of the device allows for compensating the influence of the cutting force on the elastic strain of the part, depending on the change in its rigidity. The practical value of the research includes in develop recommendations for determining the optimal parameters for the round infeed grinding cycle of the crank pins from the point of view of productivity and accuracy

Нова стратегія відновлення зубчастихт вінців

The subject matter of the research is issues related to the optimization of the technology for reconditioning large-size high precision gear rims of the drives of mining complexes, mine lifting equipment, heavy vehicles; these issues are a perspective trend for reducing the cost of reconditioning and operation of expensive unique equipment. The goal is to ensure intensifying production processes, increasing workloads and speeds, reducing the deterioration of high precision gear rims. The objective is to develop a new technology to optimize reconditioning large high precision gear rims. To achieve this, the following method is suggested – to machine gear rims after they have been surfaced by pre-milling with special hob cutters with a prominence and by final machining the teeth with special cutters equipped with hardmetal inserts that process teeth along the line of engagement, which does not require making full-length cutting teeth and increases the quality of machining, the durability of hardmetal milling cutters. The following results are obtained. Conclusions. The technology for the optimization of reconditioning large high precision gear rims with the use of special and universal hardmetal single- and double-flute cutters that have both re-sharpened cutting elements and disposable rotary tools was developed and introduced.Проводити дослідження, що стосуються питань, пов'язаних з оптимізацією технологій востановлення великих великобудівних висококоточних зубчастих колесів, що приносять гірські комплекси, шахтного підключення обладнання, тяжких транспортних середніх; Ети питання пропонують перспективну тенденцію зменшення затрат на відновлення та експлуатацію дорогостоячого унікального обладнання. Це може бути реалізовано в тому, щоб забезпечити інтенсивну ефективність виробничих процесів, збільшення робочих навантажувачів і скоростей, зменшення виносності високих зубчастих колесів. Ціль міститься в томі, щоб розробити нову технологію для оптимізації востановлення найбільших висококоточних зубчастих колесів. Для досягнення цього цілого пропонується наступний метод - образити зубчасті колеса після їх обробки путем передвірної фрезерування спеціальними фрезами з випускним виступом і кінцевою обробкою зубчими особливими фрезами, оснащеними твердими пластичними пластинами, які розробляються в лінійці, що потрібна обработки, долговечность твердосплавних фрез. Получені наступні результати. Виводи. Будучи розробленими та вбудованими технологічними оптимізаціями, відтворені великі високі високоточні зубчасті колеси із застосуванням спеціальних та універсальних твердосплавних одно- та двоканальних каналів, які мають як заточені нові елементи, так і одноразові вражаючі інструменти

DEFLECTIONS AND FREQUENCY ANALYSIS IN THE MILLING OF THIN-WALLED PARTS WITH VARIABLE LOW STIFFNESS

The disadvantage of the geometry of thin-walled parts, in terms of processing, is the low ability to resist static and dynamic loads. It is caused by the elastic deformation of elements with a low stiffness. Modelling approaches for the evaluation of deflections during machining are presented. Mathematical models of deflections, cutting forces and harmonic response are proposed. The processes of material removal and deflection of a thin-walled sample at the critical points are modelled. A frequency analysis was performed, consisting of a modal analysis of natural frequencies and a harmonic response analysis. As a result, a graph of the deflections amplitude from the frequency of driven harmonic oscillations is generated. The analysis of the obtained values was performed. As a result, the resonance frequency and maximum amplitude of oscillations for the operating parameters are determined

Increasing of Equipment Efficiency by Intensification of Technological Processes

Issues of technological processes’ intensification and increase of technological equipment efficiency are of priority value in the modern engineering. Application of various methods of hydrodynamic drag on the working fluids in rotary-wheel machines allows increasing of processing efficiency to receive finely-dispersed homogeneous mixtures with necessary characteristics. In this article the issues, connected with the liquid flows' formation in the working zone of rotary-cavitating activator are studied and the main principles of energy impact while the usage of rotor with radial channels, supplied with the elements for receiving cavitating effects, are defined. Based on the offered methodology, experimental research was conducted and calculations of the main indexes, defining efficiency of energy impact on the working medium, were held. The substantiated estimation of efficiency of hydrodynamic machines work according to the dissipative power that allows to choose the proportion of hydrodynamic settings, which provide the highest intensity of cavitating processing of processed liquids, was presented. The practical value of the research is in the studying of ways of increasing of equipment efficiency through the possibility of technological process intensification

Scientific Basis for the Substantiation of Process Regulations for the Micro-Cutting of Hardened Gears

The paper considers scientific principles of technological procedure development for the selection and assignment of parameters of velocity machining by blade tool at gear milling with due regard to the required parameters of the gear surface layer. Optimum micro-cutting conditions are determined when full participation in stock removal of all mill teeth is provided. Technological regulation of selection and setting of machining parameters is spread for gear hobbing of the spur gear wheels with fine-modular and coarse-modular hardness (220...320 HV) and after heat treatment (HRC46...63). Correlation with essential parameters of the surface layer, cutting depth, feed, speed and radius of rounding of the cutting edge of milling cutters’ teeth is established. It is scientifically grounded, tested, and proved at what modes of cutting, the radius of rounding of cutting edge of the cutting tool is made metal removal at oncoming and passing high-speed micro milling. The process of determining of minimal sliding angle, or maximum value (without the use of coolant and with coolant), in which there is no micro-cutting process taking into account variation of variable parameters of cutting conditions and geometrical parameters of hobbing cutters is modelled. For the first time, we ascertained the relation between the sliding angle and the maximum contact angle of the mill tooth with the work surface, which allowed determine the efficiency of the shaping process through coefficient (without coolant and with coolant)