Taşıt freni konstrüksiyonunda geometrik, dinamik ve termik benzerlik
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Date
1990
Authors
Karadere, Gültekin
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Journal ISSN
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Publisher
Uludağ Üniversitesi
Abstract
Konstrüksiyon dizileri, konstrüksiyon ve imalatta rasyonelleşmenin başlıca yöntemlerinden biridir. İmalat ve estetik açıdan sadece geometrik ben zerlik ele alınabileceği gibi, teknik ürünün gerçekleştireceği fonksiyon açısından dinamik, termik, kinematik vb. benzerlikler de istenebilir. Birinci bölümde, benzerlik teorisinin önemine ve konuyla ilgili temel kavramlara değinilmiştir. Sonraki üç bölümde, sırasıyla, olaylar arası benzerlik, olaylar arası analoji, konstrüksiyonların benzerliği şeklinde sınıflandırılan üç ayrı benzerlik ile bunların uygulamalarından bahsedilmiştir. Bu çalışmada benzerlik teorisinin uygulandığı elemanlar, bir diskli fren konstrüksiyon dizisinin elemanlarıdır. Bir fren için en önemli iki fak tör, fren balatalarının ısınması ve frenleme süresidir. Konstrüksiyon dizisi boyunca, sırasıyla merkezkaç gerilmelerinin ve sıcaklık artışlarının sabit kaldığı dinamik ve termik benzerlikler, fiziksel sebeplerden dolayı aynı anda tamamıyla sağlanamamaktadır. Bu nedenle beşinci bölümde, bir diskli fren konstrüksiyon dizisinde arzulanan dinamik ve termik benzerlikler açısından en uygun çözüm araştırılmıştır. Bu çözümü elde etmek için de, incelenen olayın fiziksel büyüklükleri, logaritmik diyagramlarda doğrular olarak temsil edilmiştir. Bir temel tasarıma ait büyüklükler, fiziksel bağıntılardan veya deney sonuçlarından elde edilerek, temel tasarımdan daha küçük ve daha büyük sonuç tasarımları için söz konusu büyüklüklerin alacağı değerler, diyagramlar dan kolaylıkla tayin edilebilmektedir. Altıncı bölümde, fren deneyleri için tasarlanan deney tesisatı ve ölçü aletleri tanıtılmıştır. Yedinci bölümde, benzerlik teorisi deney tesisatı şartlarına uygulanmıştır. Daha sonra, sabit boyutlardaki bir fren diskine karşılık, geometrik bakımdan kısmen benzer olarak değişen üç farklı balata alanı için, üç farklı açısal hızdan dokuz farklı hidrolik basınçla frenleme de neyleri (tek fren uygulamaları) yapılmıştır. Deney şartlarına uygun olarak yapılan benzerlik çalışmasının teorik sonuçlarına göre, sabit bir hız ve basınç için, frenleme süreleri konstrüksiyon dizisi boyunca sabit kalmış; buna karşılık disk ve balata arasındaki sıcaklık artışları, referans büyüklük olarak seçilen balata radyal genişliğinin ölçeğiyle azalmıştır. Bu teorik sonuçlar, deney sonuçlarıyla çizilen logaritmik diyagramlarda büyük bir yaklaşımla doğrulanmıştır.
Construction series are one of the basic methods in rationalizing of the construction and the manufacturing. Jus t as geometrical similarities can he taken into account from the point of view of manufacturing and esthetics, so dynamical, thermal, kinematical similarities, and so on, may also be re quired from the point of view of some functions that is taken on by techni cal product. In the first chapter, the importance of the theory of similarity and basic concepts regarding the subject have been mentioned. In the latter three chapters, three different similarities classified in similarity between phe nomena, analogy between phenomena, similarity in constructions, respectively, and their applications have been mentioned. In this study, elements to which theory of similarity are applied are the elements' of a disk brake construction series. The most two important fac tors for a brake are the* heating of brake linings and duration of brake ap plication. Dynamical and thermal similarities in which centrifugal stresses and the increases in temperature remain constant throughout the construction se ries, respectively, can not simultaneously be satisfied due to the physical reasons. Therefore, in the fifth chapter, the most convenient solution from the point of view of dynamical and thermal similarities desired in the disc brake construction series are studied. In order to obtain this solution, phys ical quantities of the phenomenon studied are represented as straigth lines in logarithmic diagrams. By obtaining the quantities belonging to a basic de sign from the physical relations or experimental results, the values to be taken by the quantities concerned for the designs which are smaller and larg er than the basic design can be easily found from the diagrams. In the sixth chapter, the test rig and measurement units designed for the experiments in braking have been introduced. In the seventh chapter, theory of similarity have been applied to the conditions other than ideal ones established in the test rig. After then, for a disc brake which has con-- VI stant dimensions, experiments in braking (only one brake applications) have been carried out for three different lining surface area partially similarly changing in geometry and for three different angular velocity and nine differ ent hydraulical pressure, each of which changes in accordance with the con ditions prescribed in a certain manner. According to the theoretical results of the study made in accordance with the experimental conditions, braking durations for the constant velocity and pressure have been constant throughout the construction series, increases in temperature between disc and lining had been reduced in accordance with the scale of lining radial width chosen as a reference quantity. These theo retical results have been justified in great accuracy with the logarithmic diagrams drawn by means of experimental results.
Construction series are one of the basic methods in rationalizing of the construction and the manufacturing. Jus t as geometrical similarities can he taken into account from the point of view of manufacturing and esthetics, so dynamical, thermal, kinematical similarities, and so on, may also be re quired from the point of view of some functions that is taken on by techni cal product. In the first chapter, the importance of the theory of similarity and basic concepts regarding the subject have been mentioned. In the latter three chapters, three different similarities classified in similarity between phe nomena, analogy between phenomena, similarity in constructions, respectively, and their applications have been mentioned. In this study, elements to which theory of similarity are applied are the elements' of a disk brake construction series. The most two important fac tors for a brake are the* heating of brake linings and duration of brake ap plication. Dynamical and thermal similarities in which centrifugal stresses and the increases in temperature remain constant throughout the construction se ries, respectively, can not simultaneously be satisfied due to the physical reasons. Therefore, in the fifth chapter, the most convenient solution from the point of view of dynamical and thermal similarities desired in the disc brake construction series are studied. In order to obtain this solution, phys ical quantities of the phenomenon studied are represented as straigth lines in logarithmic diagrams. By obtaining the quantities belonging to a basic de sign from the physical relations or experimental results, the values to be taken by the quantities concerned for the designs which are smaller and larg er than the basic design can be easily found from the diagrams. In the sixth chapter, the test rig and measurement units designed for the experiments in braking have been introduced. In the seventh chapter, theory of similarity have been applied to the conditions other than ideal ones established in the test rig. After then, for a disc brake which has con-- VI stant dimensions, experiments in braking (only one brake applications) have been carried out for three different lining surface area partially similarly changing in geometry and for three different angular velocity and nine differ ent hydraulical pressure, each of which changes in accordance with the con ditions prescribed in a certain manner. According to the theoretical results of the study made in accordance with the experimental conditions, braking durations for the constant velocity and pressure have been constant throughout the construction series, increases in temperature between disc and lining had been reduced in accordance with the scale of lining radial width chosen as a reference quantity. These theo retical results have been justified in great accuracy with the logarithmic diagrams drawn by means of experimental results.
Description
Keywords
Benzerlik teorisi, Konstrüksiyon, Similarity theory, Fren, Brake, Construction
Citation
Karadere, G. (1990). Taşıt freni konstrüksiyonunda geometrik, dinamik ve termik benzerlik. Yayınlanmamış doktora tezi. Uludağ Üniversitesi Fen Bilimleri Enstitüsü.