• Journal of Digital Convergence
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• v.13 no.11
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• pp.171-178
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• 2015

The disk cover is installed to protect brake disk and calliper and it's removed right before delivering to customers. The temperature of disk cover was measured driving test vehicles(2000cc, diesel) in this study. The highest temperature measured for the driving test(120km/h-braking(0.3G)-stop-120km/h-braking(0.5G)-stop) was $260{\sim}270^{\circ}C$ in the upper part of the disk cover and the temperature varied considerably around the disk cover. It can be inferred from this temperature distribution around the cover that the major heat transfer from hot disk to cover was through convection. In other words, the hot air generated by braking friction moved up to the upper part of the disk cover. And only the upper area of the disk cover was melted down during this driving test. The thickness of disk cover was increased to 1.0mm from 0.7mm and 1 paper of masking tape was pasted in the upper region of the disk cover. Then the cover endured the heated air formed by braking friction during the driving test.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.6
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• pp.1479-1489
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• 1995

In this study, tensile strength and modulus were evaluated for a filament wound ring specimen by split disk test and compared with the theoretical values obtained by the rule of mixtures. The circumferentially wound ring specimens were prepared from 4 types of material systems. The results showed that the measured strengths of the composite systems were considerably lower than the theoretical values due to the local bending stresses around the split disk edges. for the measurement of elastic moduli of the filament wound ring specimens, the effect of friction on the strain of the ring must be taken into account. But the effect of friction between the split disk fixture and the ring specimen can be eliminated by averaging the moduli for loading and unloading state with maintaining the same crosshead rates. The measured elastic moduli of ring specimens showed very good agreement with the theoretical values.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1690-1695
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• 2003

In order to investigate the mechanism of brake squeal noise, the sound and vibration of an actua1 brake system were measured using a brake dynamometer. The experimental results show that disc run-out varies with brake line pressure and the factor of squeal generation is the run-out due to the misalignment of brake disk. A three degrees of freedom friction model is developed for the disk brake system where the run-out effect and nonlinear friction characteristic are considered. The results of numerical analysis of the model agree well with the experimental results. Also, the stability analysis of the model was performed to predict the generation of brake squeal due to the design parameter modification of brake systems. The results show that the squeal generation depends on the nm-out rather than the friction characteristic between the pad and the disk of brake.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.1
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• pp.54-59
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• 2006

An analytical solution for deflection-load characteristics of a conical disk spring used especially in the automotive manual transmission clutch applications is proposed in order to take into account the effects of friction and large deformation. The conical disk spring, or the diaphragm spring, has a hinge support, an application point of release load at the tip of the fingers and an application point of clamp load near but inside the outer perimeter of the conical disk spring. The friction coefficient is assumed to be a constant regardless of the speed of deflection and the magnitude of loads. Comparison with experimental shows a good agreement with the analytical prediction. Also, the sensitivity of the clamp load due to variations in the geometrical parameters of the conical disk spring is calculated and discussed.

• Tribology and Lubricants
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• v.17 no.5
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• pp.358-364
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• 2001

Disk brake system transforms a large amount of kinetic energy to thermal energy in a short time. As the size and speed of automotive increases in recent years, the disk brakes absorbs more thermal energy. And this thermal energy can cause an unacceptable braking performance due to the high transient temperature, that is attained at the friction surface of brake disk and pad. Although these high temperatures are one of the biggest problems. In this study, the overall thermal behavior of ventilated disk brake system was investigated by numerical method. The 3-Dimensional unsteady model was simulated by using a general purpose software package “FLUENT” to obtain the temperature distributions of disk and pad. The model includes the more realistic braking method, which repeats braking and release. The effects of several parameters such as the repeated braking, inlet air velocity and thermal conductivity on the temperature distribution were investigated.

• KSTLE International Journal
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• v.3 no.2
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• pp.114-118
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• 2002

In this work, head-disk interactions are studied when flying height becomes lower than laser bump height on the landing zone of a disk. With the reduction of the spinning speed in a spin stand, the flying height is decreased under the height of laser bumps. Conventional and padded pico sliders sweep between landing Bone and data zone and, then, the dynamic behavior of the pico sliders and head-disk impacts are investigated using AE and stiction/friction signals. After 200n cycle-sweep tests, bearing analysis and AFM analysis indicate that there are some signs of wear and plastic deformation in the landing zone of a disk, although AE and stiction/friction signals are not significantly changed during the sweep tests. The experimental results of this paper suggest that in CSS tests at component level, more rigorous examination methods of wear and plastic deformation might be necessary as flying height becomes getting lower.

• Tribology and Lubricants
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• v.23 no.1
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• pp.19-28
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• 2007

Mechanical Brake system is inevitable equipment for stability of train and speed of the train. Especially brake disk and brake pads are core parts of mechanical brake system. It was investigated with tribological characteristics of brake discs for train by using lab-scale dynamometer. Gray cast iron disk was most attacked with sintered brake pad. Alloyed steel disk and NCM cast iron disk had suitable friction coefficient, high stability and low disk attack to the sintered brake pad. But at the view of economy, low alloyed cast iron will be most suitable choice.

• Tribology and Lubricants
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• v.16 no.5
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• pp.395-402
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• 2000

The effect of particulate contamination on friction and wear between a negative-pressure picoslider and a laser-textured disk was studied. Particles of different concentrations, materials and sizes were injected to the head-disk interface (HDI), consisting of disks with various textures, at the same speed. In a contaminated environment, durability of head-disk interface gradually decreased as the particle concentration increased. Large particles caused HDI failure early and resulted in an extensive damage to the slider and disk surfaces. Hard particles also caused HDI failure earlier and damages more extensive than soft ones. Based on the test results, mechanisms of HDI failure with picoslider were presented.

• Tribology and Lubricants
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• v.13 no.1
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• pp.21-27
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• 1997

The friction and wear behavior of undulated surfaces made of tin base babbit are examined experimentally at the low sliding speed with severe loading condition. Steel is used as counterface disk material under pin-on-disk type sliding condition. Undulated surfaces can improve the friction and wear properties under dry friction condition since undulated surfaces trap wear particles in their cavities and prohibit wear particles from agglomerating. However, under boundary lubrication condition, friction and wear properties of undulated surfaces are inferior to those of flat surfaces. It is shown that land width and the ratio of wear volume to cavity volume are the most important factors in friction behavior of undulated surfaces under dry friction condition, and there exists optimum land width minimizing friction and wear of undulated surfaces.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.807-810
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• 1995

The effects of weae particles on the friiction and wear behavior of metals in dry sliding conditions are presented. The tribological test were performed using pure metal specimens which were selected based on their degrees of compatibility and hardness ratio. Friction and wear experiments were conducted using both pin-on-disk and reciprocating pin-on-plate type tribotesters to investigate the effect of motion history. Experimental results show that in the case of dry sliding the frictional behavior observed during pin-on-disk test differed form that of pin-on-reciprocator test for the given set of material pairs. The friction coefficient and wear rate were found to be higher for the pin-on-disk tests. It is suspected that the sliding motion of the pin affects the wear particle dynamics, which in turn influences the frictional behavior. The effect of material pair properties seemed to be relatively smaller than that of wear particles. The results of this paper is expected to aid in the design of mechanical systems for best tribological performance.