Hasan Öktem

Advanced friction-wear behavior of organic brake pads using a newly developed system

Abstract The objective of this study was to investigate the influence of an advanced performance system on the tribological behavior of brake pad material using a specially designed brake pad tester system following standard SAE J-661. The tribological behavior and friction and wear characteristics of the organic brake pad samples were evaluated. During braking tests, the samples, in contact with a cast iron disk, were studied at different disc speeds, temperatures, and braking cycles under a constant pressure. In order to understand the friction and wear behavior, the unworn surfaces, worn surfaces, and wear debris were characterized by means of scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX). Furthermore, the surface characteristics and differences in the wear modes of the brake pad samples were examined. Wear debris was permitted to deform the brake pad surfaces, leading to friction layers and enabling the estimation of the friction behavior of the brake pads. The results showed that the best friction–wear behavior was obtained with lower braking cycles at low speeds and temperature. Thus, the newly developed brake pad tester system proved very effective in evaluating the performance of the brake pad samples.

Development of A New Type Brake Pad Frıctıon Tester

An improvement in automotive industry; high coefficient of friction and wear resistance-non asbestos friction pads can be produced. Various types of test apparatus are constructed for wear, friction and noise level detection. In this study, natural dust reinforced brake pads were tested and characterized by SAEJ-661 standards. For this purpose computer aided new type of brake pad friction tester produced. This test machine consists of hydraulic control, mechanical design, and automation systems. The main difference of this new type of tester compared to other is that brake pads can be tested in real dimension and test conditions with high precision. Also noise levels can be measured by the test machine. At the end of the study, real brake pad friction responses can be determined with fast and high precision by newly developed friction pad tester. The friction coefficient is increased rapidly at the beginning with the disc speed increased and the started to decrease and then continued constantly. From this, it is concluded that the whole brake pad pattern is related to surface contact and two interface resistances.

Evaluation of The Physical Properties of Hazelnut Shell Dust-Added Brake Pad Samples Treated With Cryogenic Process

After understanding that asbestos fibers are harmful to human health; researchers have investigated for alternative and eco-friendly materials. Agricultural products can be an example of these alternative and environmentally friendly materials because they are easily supplied . Thus, in this study, asbestos-free automotive brake pads produced from %7 hazelnut dusts with other seventeen additives. Hazelnut shell is preferred because it is widespread in our country. Cryogenic process applied at -80°C to the brake pads. Before and after cryogenic treatment, the produced brake pads properties such as water absorption, hardness test, porosity and microstructural examinations were investigated. The hardness values of brake pads increases after cryogenic and cyclic-cryogenic process. The highest values obtained for the B-CYC sample.

Characterization of Water and Oil Absorption Properties of Organic Additive Brake Pad Samples

Alınma: 19.01.2018 Kabul: 09.03.2018 Son yıllarda otomotiv teknolojisinin gelişmesiyle birlikte, fren balatası için alternatif kompozisyon arayışı da artmıştır. Kompozisyonunda birçok tozu barındıran fren balatalarının, performansının yanında, alternatif tozlardan üretilmesi de beklenmektedir. Alternatif tozlarda, çevre dostu olması ve maliyetinin düşük olması istenen en önemli faktörlerdendir. Bu çalışmada, ülkemizde yüksek rezerve sahip boraks ve wollastonite kullanılmıştır. Alternatif tozlarla üretilen fren balatası numunelerinin su ve yağ emme davranışları test edilmiştir. Elde edilen sonuçlar referans olarak kullanılan ticari fren balataları ile kıyaslanmıştır. Suda bekletilen numunelerin sertlik değerleri, yağda bekletilen numunelere göre daha fazla düşmüştür. Katkı maddesi olarak wollastonite kullanılan numunelerde daha az sertlik değişimi gözlenmiştir. Boraks katkılı fren balatalarının yoğunluk değerleri referans fren balatasına daha yakın değerlerdedir. Wollastonite katkılı fren balatalarında gözlemlenen ağırlık değişimi ise ticari fren balatası numunesine yakın değerlerde elde edilmiştir.