• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2000.11a
• /
• pp.141-146
• /
• 2000

It has many variables and factors to design the friction materials for automotive brake pads. In this study, the friction and wear characteristics of automotive blake pads have been studied using 1:l full size dynamo meter. Using conventional manners, it takes a great of time and efforts to know that it affects the each raw materials for friction characteristics. For the purpose of examining the effect of each major raw materials, we used the more convenient Taguchi L9 ($3^4$) orthogonal matrix and 1/5 scale dynamo machine for evaluation of the friction characteristics of composite brake pads.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2012.05a
• /
• pp.201-203
• /
• 2012

The establishment of the technology for evaluating friction resistance and pipe pressure and the relation of the fluid characteristics and pumpability of concrete is essential for the evaluation of concrete pumping performance for high speed construction of super-tall building. So, this study focuses on quantitative evaluation of concrete fluid characteristics and surface friction resistance under the change of concrete mix proportion and pumping condition. In this study, we measured the rheology of concrete and pipe pressure and surface friction characteristics when pumping. And, relations between the rheology characteristics of concrete and pumping performance was investigated by experiment. As the result of the experiment, high regression between the surface friction and pressure gradient was confirmed. And, prediction model to evaluate the friction resistance coefficient and pipe pressure reduction coefficient was suggested.

• Tribology and Lubricants
• /
• v.22 no.3
• /
• pp.149-154
• /
• 2006

This paper presents the braking friction and wears on the rubbing surfaces of a friction pad-disk brake. In this study, four friction disk specimens are sampled from unused and used disks in which are taken from the disk brake system when the friction induced vibration and noise problems have been occurred during a braking period at a running period of 10,000 km, 20,000 km, and 30,000 km in random. The experimental results indicate that the tribological characteristics of an unused disk brake shows equal and stable as a friction coefficient and temperature distributions during a braking friction/wear test period including a total friction mode from the start to running periods. But the used disk brake shows unstable and uneven friction modes between an outside and inside rubbing surfaces of a disk brake in terms of a friction coefficient and wears. This may lead to a friction induced friction vibration and noise problems of a used disk brake.

• Journal of the Korean Society for Precision Engineering
• /
• v.19 no.7
• /
• pp.51-58
• /
• 2002

In this paper, the characteristics of silicon wafer surface which is textured by KOH anisotropic etching method and mechanical polishing are investigated from the viewpoint of stiction and friction. It was found that the characteristics of stiction and friction of each textured surface are dependent on the contact area characterized by surface parameters such as bearing length ratio and peak count. To find the mechanism of the variation of stiction and friction in textured surface, OTS SAM coated wafer was used. In this case, the variation of stiction and friction was diminished, Therefore, it is concluded that the reason of variation of stiction and friction on textured surface is mainly caused by capillary which in turn is affected by the surface topography

• Tribology and Lubricants
• /
• v.29 no.4
• /
• pp.223-227
• /
• 2013

A GAF (generated axial force) is produced at a plunging-type CVJ (constant velocity joint). A high GAF can cause vibrations in a vehicle. Grease is used to reduce friction between the roller and the track of the outer case of a CVJ. The grease performance depends on the surface conditions and operating temperature. The surface of the outer case is extremely rough and hard. In recent times, the maximum operating temperature of CVJs has crossed $140^{\circ}C$, because the exhaust line is now located close to the CVJ. In this study, we examined the friction characteristics of friction additives at $25-150^{\circ}C$ and determined an optimal formulation with a low friction coefficient. This formulation can be used to develop low-friction grease that can reduce the GAF produced at a CVJ by approximately 7-26%.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.8 no.3
• /
• pp.7-12
• /
• 2009

This study aims to find the friction welding and induction harden conditions, which are obtained by welding conditions, and the friction welding characteristics and induction harden conditions of tubular shaft were investigated with respect to low load test, high load test. Friction welding and induction harden machine have been widely used in manufacturing reflects of metal. The material of solid and tubular shaft selected that is used for parts of automobile steel. Such as steel are easy to be machined because of their proper material. As a result I obtained the data of friction welding conditions makes good and the condition of friction and get the tubular condition. The purpose of this study is to find fatigue test condition and induction harden characteristics design for tubular shaft.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.9 no.6
• /
• pp.1535-1540
• /
• 2008

This paper are using a test apparatus developed in the laboratory, friction and wear characteristics of various rubbers have been analyzed by experimental study. Friction coefficient has been calculated from the measured normal force and friction force under various speed operating conditions, such as, loads and temperatures. The tire are used in a automobile, the relations between the various operating conditions and friction characteristics have been verified.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.26 no.4
• /
• pp.660-666
• /
• 2002

It has many variables and factors to design the friction materials for automotive brake pads. The purpose of this study is to develop the proper method for design of low-cost and to know friction characteristics of each raw materials. For the purpose of examining the effect of each major raw materials, we used the Taguchi L9(3$^4$)orthogonal matrix and 1/5 scale dynamo machine for evaluation of the friction characteristics of composite brake pads. By adapting the Taguchi method, it is easy to investigate the influence of each component in complicated composites friction materials. After analyzing the testing results by the Taguchi method, the effect of factors and levels influenced friction behavior was studied.

• Tribology and Lubricants
• /
• v.23 no.6
• /
• pp.306-311
• /
• 2007

This paper presents the friction characteristics of pb-fres pin bushing bearings for an automotive gasoline engine. The external load is 100 N to 600 N and the speed of the pin bushing bearing is 1000 rpm to 3000 rpm against the rubbing surfaces. And the contact modes of rubbing surfaces between a piston pin and a pb-free pin bushing specimen are a dry friction, an oil lubricated friction and a mixed friction that is starved by a lack of engine oil. Two influential factors of a contact rubbing modes and a material property are very important parameters on the tribological performance of a friction characteristic between a piston pin and a pb-free pin bushing. The experimental result shows that the pin bushing speed of 2000 rpm shows a typical oil film lubricated sliding contact mode in which means that as the applied load is increased, the friction loss is increasing. But other contact mode depending on the speed and the load may affect to the fiction coefficient without a regular and uniform trend. In summary, the oil lubricated rubbing surface definitely decreases a running-in period in short and increase oil film stiffness, and this may leads the reduction of a friction loss.

• Tribology and Lubricants
• /
• v.25 no.4
• /
• pp.243-249
• /
• 2009

A magnetic clutch consists of pulley and disk. It delivers and isolates the power needed for the operation of the compressor used in automotive air conditioning system. To improve the performance, efficiency and durability of automotive air conditioning system, appropriate design of pulley, disk and system working parameters(the magnitude of magnetic force, and so on) is necessary. For that goal, it is required to understand the friction characteristics of magnetic clutch for the initial operating time. In this study, friction tests were carried out in order to investigate the effect of sliding velocity on the friction characteristics of magnetic clutch using pin-on-disk type friction and wear tester. For experiments, pulley and disk used in real automotive air conditioning system were considered. Friction experiments were conducted under various sliding velocities, and coefficients of kinetic friction were obtained. Under the experimental conditions considered in this study, the coefficients of kinetic friction increased with the increase of test number(sliding distance) and decreased with the increase of sliding velocity.