• Journal of the Korea Society of Computer and Information
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• v.29 no.11
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• pp.317-324
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• 2024

This study is on the improvement of wear resistance of roller tappet assembly which is applied to V-956 engine. Although the TBO(Time Between Overhauls) of the engine and roller tappet assembly is more than 9,000 engine operating hours, about 60% engines which were operated within TBO suffered severe wear on roller tappet assembly and failed to operated normally. To find out the cause of wear of these roller tappet assembly, finite element analysis was performed using ABAQUS based on the investigation into roller tapper assembly and the operating conditions of V-956 engine. As a result, it was found that wear occurred due to the low hardness value of the roller surface under certain operating conditions, and based on the analysis results, we proposed the optimal hardness value for improving wear resistance on the surface of the roller tappet assembly. The results of this study were applied to the mass production of the corresponding roller tappet assembly and are currently in use.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.223-229
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• 2016

In this study, a cold forging process was developed for the roller tappet housing of an engine valvetrain system. A tappet sample was manufactured and subjected to an endurance test. The material properties were obtained from a compression test, and forging analysis was carried out to design a forging process using a commercial program, Deform-3D. The forging process was set up based on the analysis results, and a die set and sample tappet housing were manufactured. To evaluate the sample, the dimensional accuracy, surface roughness, parallelism, and concentricity were measured and confirmed. To evaluate the actuation and durability, a special test rig was developed to simulate the valvetrain system of the engine. An actuation test was performed based on the idle speed of a general diesel engine, and an endurance test was done based on the maximum speed. The results show minor wear of 0.002 mm. The developed test rig will be used to evaluate the actuation and durability of other valvetrain parts.