Вплив температури і тиску на характеристики напружено-деформованого стану і герметичності вузлів вологозахисту плівкових конденсаторів

Abstract

У роботі представлено теоретичні і експериментальні дослідження по вирішенню проблеми забезпечення міцності і герметичності вузлів герметизації у вигляді циліндричних компаундованих горловин з прохідними виводами на прикладі плівкового конденсатора К-78. Розроблено математичну модель силової взаємодії заполімеризованого компаунда, яка має контакт з оболонкою і прохідним виводом при температурі від +100 °С до -60 °С. Розроблено математичну модель впливу надлишкового тиску повітря і витікаючі з неї технології полімеризації компаунда. Представлені практичні розрахунки елементів розроблених конструкцій на прикладі плівкових конденсаторів К-78 трьох типорозмірів. Розроблено і введено в практику тензометричний спосіб перевірки конструкцій на герметичність, висотність і визначення часу закінчення полімеризації компаунда. Експериментальними дослідженнями підтверджено теоретично отримані результати. В работе представлены теоретические и экспериментальные исследования по решению проблемы обеспечения прочности и герметичности узлов герметизации в виде цилиндрических компаундованих горловин с проходными выводами на примере пленочного конденсатора К-78. Разработана математическая модель силового взаимодействия заполимеризованого компаунда, контактирующего с оболочкой и проходным выводом при температуре от +100 °С до – 60 °С. Разработана математическая модель влияния избыточного давления воздуха и вытекающие из нее технологии полимеризации компаунда. Представленные практические расчеты элементов разработанных конструкций на примере пленочных конденсаторов К-78 трех типоразмеров. Разработан и введен в практику тензометрический способ проверки конструкций на герметичность, высотность и определения времени окончания полимеризации компаунда. Экспериментальными исследованиями подтверждено теоретически полученные результаты. The analysis of the design features of modern products of REA shows that solving the problems of providing protection against moisture and stability when changing the temperature and pressure of the environment has led to the use of new materials with insufficiently studied properties and the unification of such heterogeneous materials. Mechanical interaction arising in such structures can have a significant effect on both the occurrence of basic electrical processes and the performance of the product as a whole. However, at present, the design of REA is often carried out only in a purely radio engineering, without the necessary calculations of strength, without measuring the stresses and assessing the tense state of structures in general and their individual elements. At the same time, modern requirements and the future of radioelectronics, as well as the scope of its use, put together in one row with exclusively radio-electronic tasks the problem of ensuring their mechanical strength and reliability. In this paper an attempt is made to fill this gap to some extent. For this purpose, the K-78 (polystyrene film) condenser has been selected, which is widely used in various medical devices, in particular in defibrillators for the operation of the heart that has stopped during operation. This condenser was characterized by the depressurization of the moisture protection unit due to cracking the compound and detaching it from the cylindrical body and the output. In order to understand the causes of depressurization, a mathematical model is developed in which a thin-walled aluminum body is taken for a cylindrical shell loaded in part of its length or along the entire length of the distributed contact pressure from the side of the compound, and then the deformation of this shell is considered. To eliminate the detachment of the compound from the shell wall, it was proposed to significantly increase the flexibility of the shell so that it more easily followed the deformations of the compound by cutting the part of the shell forming n-sectors that form the sector structure. Another idea is considered to ensure the tightness and strength of the compound by replacing the three-layer construction of two two-layers with the creation of a ring groove in the layer of the compound between the shell and the output, which will enable the thickness of the compound to be adjusted in each of the constructions. The radial dimensions of the grooves are calculated, which ensure the reliability, tightness and durability of the design of the moisture protection unit. For their implementation, we recommend two variants of devices that form a given form of the compound. In addition to the contact pressure acting on the interface of the contacting materials, the pressure of the knot is negatively affected by excessive air pressure at a temperature of 100 °C, which is inside the condenser. Calculations were carried out in the axial and radial directions, the results of which showed that this can not be the reason for the depressurization of the moisture protection unit, if the formation of adhesive joints between the compound and the walls of the body, as well as between the compound and the output, has ended. Finally, the experimental studies are aimed at checking the theoretical positions, methods and means of ensuring the tightness of the hermetic units. The strain gauge method of checking sealing structures for tightness, height, and determining the time of completion of polymerization of the compound is developed and introduced into practice. The methods of circuit and consistent temperature compensation of strain measurement error at the thermal shock are developed. In total nine possible variants of the organization of the unit of moisture protection and alternative technology of pouring and polymerization of the compound were worked out. The obtained results can be found not only in the capacitors, but in all capacities, which have similar units of moisture protection.