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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Studie av smörjsystem / Study of lubrication systems

Axelsson, Erik, André, Samuel January 2011 (has links)
Målet med detta arbete är att undersöka smörjsystemet på två utsatta leder på en Boomer E2C. Förfrågan om examensarbetet kommer från Atlas Copco Rock Drills AB i Örebro som också tillverkar maskinen. Atlas Copco Rock Drills AB har idag ett fettsmörjningssystem som upprätthåller funktionerna på lederna. Uppgiften är att sammanfatta och utvärdera dagens system samt att finna nya lösningsförslag som skulle kunna ersätta eller delvis ersätta systemet. Information har hämtats från dokumentation, ritningar och samtal med konstruktörer på företaget. Efter att alla förutsättningarna för lederna specificerats så har lösningsförslag sökts. Genom att träffa lagerleverantörer och söka artiklar så har idéer formats. Brainstorming har använts för att kunna se nya lösningar. Undersökningen har visat att det finns problem med dagens lösning vad gäller slanghaverier och driftstopp i fält. Atlas Copco AB uttrycker även att kunskapen och dokumentationen angående systemet är otillräckligt. Efter artikelsökning så kan konstateras att forskningen och kunskapen på området med tungt belastade, oscillerande och fettsmörjda leder är liten. Dimensionering sker ofta med hjälp av erfarenhet och med tankesättet ”det har fungerat förut”. När lösningsförslagen har jämförts så har detta gjorts genom att använda metoden AHP (Analytic Hierachy Process). Med denna metod så jämför man kriterierna från kravspecifikationen med lösningsförslag så att man matematiskt kan räkna fram ett vinnande lösningsförslag. Resultatet visar att en smörjfri lösning skulle teoretiskt vara att föredra. Denna skulle tillverkas av en modern polymer och kompletteras med en inre tätning och ett yttre skydd. Atlas Copco rekommenderas att testa de olika förslagen för att komma fram till vilken som är bäst lämpad för applikationen. / The goal of this work is to investigate the lubrication system on two exposed joints on a Boomer E2C. The request for the thesis comes from Atlas Copco Rock Drills AB, Örebro, which also manufactures the machine. Today Atlas Copco Rock Drills AB has a grease lubrication system that secures the function of the joints. The task is to summarize and evaluate the current systems and to find new solutions that would be able to replace or partially replace the current system. Information was gathered from documents, construction drawings and conversations with engineers at the company. Solutions and ideas have been formed by meeting stock suppliers and searching for articles. Brainstorming has been used in order to find new solutions. The investigation has shown that there are problems with the current solution in terms of hose failures and downtime in the field. Atlas Copco AB also expresses that there is a lack of documentation and knowledge regarding the lubrication system. After the various article searches it became clear that research and knowledge in the area with heavy duty, oscillating and grease lubricated joints is insufficient. The design is often done with the help of experience and with the mindset "it has worked before." When the solutions and ideas have been compared, this has been done by using AHP (Analytic Hierarchy Process). This method compares the criteria that must be fulfilled by the solutions and then calculates the best one. The results show that a lubrication-free solution would theoretically be preferable. This would be produced by a modern polymer and supplemented with an inner seal and an outer protection. Atlas Copco is recommended to test the various proposals to be able to decide which the best solution for the application is.
2

Impact Of Contaminants on Blade Bearing’s Lifetime

Tomy, Abel January 2024 (has links)
The global shift towards sustainable practices extends across various domains, including energy generation. Wind energy, a cornerstone of this transition, relies heavily on the efficient operation of wind turbines. This study investigates the impact of contaminants on the longevity and performance of blade bearings in wind turbines. Under real-world conditions, blade bearings frequently operate in suboptimal lubrication environments, attacked by contaminants like wear particles and water. This research, conducted in collaboration with Vattenfall R&D, aims to focus on the specific effects of these contaminants.  Through comprehensive literature reviews and tribological tests, the study evaluates the load in rolling elements, examines the contact conditions between raceways and rollers, and determines the effects of contaminants on wear volume. Findings indicate that most pitch movements in blade bearings are limited to small angles, influencing lubrication requirements and wear patterns. Chloride-based EP additives, probably inactive due to insufficient activation temperatures, show potential for hydrolysis-induced corrosion.  Wear tests suggest that used grease may perform better under certain conditions compared to fresh grease, highlighting the complexity of lubricant performance. Long-term tribological tests show that FUCHS LUBRITECH GLEITMO 585K exhibits better wear resistance compared to Shell Rhodina BBZ in test conditions.  The study underscores the importance of proper lubrication and contamination management in extending blade bearing life. Recommendations include regular grease monitoring and analysis, understanding tribo-corrosion effects, and improving seal compatibility to enhance overall bearing reliability.
3

Разработка новых конструкций реверсивных шестеренных насосов для систем смазки возвратно-вращательных механизмов экскаваторов : магистерская диссертация / Development of new designs of reversible gear pumps for lubrication systems of return-rotational mechanisms of excavators

Чибиров, А. Б., Chibirov, A. B. January 2019 (has links)
Диссертация на тему «Разработка новых конструкций реверсивных шестеренных насосов для систем смазки возвратно-вращательных механизмов экскаваторов» содержит 95 страниц текста, рисунков – 49, формул – 22, использованных источников – 18, иллюстрационный альбом, включающий 15 листов формата А1 графической части. Ключевые слова: системы смазки, реверсивные механизмы, реверсивный насос, шестеренный насос, консистентная смазка, циркуляционная смазка, карьерные экскаваторы, привод поворота, привод подъемной лебедки. Предмет исследования: проблемы систем смазки современных карьерных экскаваторов. Цель работы: разработка схемы и конструкции насоса, обеспечивающего бесперебойную подачу смазывающего вещества при постоянном реверсировании его ведущего вала. Итогом работы является разработка двух концептуальных вариантов шестеренного реверсивного насоса для узлов, совершающих возвратно-вращательные движений. Насосы могут работать от основного привода, без использования дополнительного двигателя. Так же в работе представлен пример использования данных насосов в узлах карьерного экскаватора ЭКГ-20, таких как редуктор подъемной лебедки и редуктор привода поворота с расчетом параметров насоса для последнего. В процессе работы над диссертацией была оформлена заявка на патент на полезную модель «Реверсивный шестеренный насос». Заявка зарегистрирована в Роспатенте с приоритетом от 23.04.2019. Регистрационный номер заявки 2019112339. / The dissertation on the theme "Development of new designs of reversible gear pumps for lubrication systems of return-rotational mechanisms of excavators" contains 95 pages of text, figures – 49, formulas – 22, used sources – 18, an illustrative album, including 15 sheets of A1 format of the graphic part. Key words: lubrication system, reversing mechanisms, a reversible pump, gear pump, grease lubrication, circulating lubrication, mining shovels, swing drive, the drive of the lifting winch. Subject of research: problems of lubrication systems of modern mining excavators. The purpose of the work: development of the scheme and design of the pump, ensuring uninterrupted supply of lubricant with constant reversal of its drive shaft. The result of the work is the development of two conceptual variants of the gear reversible pump for units performing reciprocating movements. Pumps can operate from the main drive, without the use of an additional engine. Also the paper presents an example of the use of these pumps at the nodes of a mining shovel EKG-20, such as reducer lift winch, and the gear drive rotation calculation of pump parameters for the latter. In the process of working on the thesis was issued a patent application for a utility model "Reversible gear pump". Application to patent with priority of 23.04.2019. Registration number of the application 2019112339. The practical usefulness of the work lies in the fact that this pump is ready for use in many areas of engineering, as shown by the example of mining equipment.

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