• International Journal of Automotive Technology
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• v.8 no.6
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• pp.723-730
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• 2007

The typical design of automotive driveshafts generally utilizes Constant Velocity(CV) joints as a solution to NVH. CV joints are an integral part of vehicles and significantly affect steering, suspension, and vehicle vibration comfort levels. Thus, CV joints have been favored over universal joints due to the constant velocity torque transfer and plunging capability. Although CV joints are common in vehicle applications, current research works on modeling CV joint friction and assumes constant empirical friction coefficient values. However, such models are long known to be inaccurate, especially under dynamic conditions, which is the case for CV joints. In this paper, an instrumented advanced CV joint friction apparatus was developed to measure the internal friction behavior of CV joints using actual tripod-type joint assemblies. The setup is capable of measuring key performance of friction under different realistic operating conditions of oscillatory speeds, torque and joint installation angles. The apparatus incorporates a custom-installed triaxial force sensor inside of the joint to measure the internal CV joint forces(including friction). Using the designed test setup, the intrinsic interfacial parameters of CV joints were investigated in order to understand their contact and friction mechanisms. The results provide a better understanding of CV joint friction characteristics in developing improved automotive driveshafts.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.160-163
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• 2005

The cute. race of CV(constant velocity) Joint is an important load-supporting automotive part, which transmits torque between the transmission gear box and driving wheel. The outer race is difficult to forge because its shape is very complicated and the required dimensional tolerances are very small. The forged CV Joint investigated in this study has six inner ball grooves requiring high operational accuracy. Therefore, the precise measurement of forged CV Joint is very important to guarantee the sound operation without noise and abnormal wear. In this study, unique in-situ measuring system designed specifically to measure the dimensional accuracy of six inner ball grooves of CV joint has been developed and implemented in shop environments. Newly developed system shows high measurement accuracy with simple operational sequence.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.230.1-230.1
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• 2005

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.156-159
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• 2005

The outer race of CV(constant velocity) joint is an important load-supporting automotive put that transmits torque between the transmission gear box and driving wheel. The outer race is difficult to forge because its shape is very complicated and the required dimensional tolerances are very small. To guarantee the dimensional accuracy of the forged CV Joint, the quick and precise measurement is required to increase the inspection speed of forged products. Therefore in this study, PP(Pre-Position) Device to decrease the inspection time of measuring system has been developed to cope with forging cycle time. The measured inspection time confirms that the PPD is very effective in decreasing inspection time.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.399-402
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• 2006

The outer race of CV(constant velocity) joint is an important load-supporting automotive part, which transmits torque between the transmission gear box and driving wheel. The outer race is difficult to forge because its shape is very complicated and the required dimensional tolerances are very small. Traditional warm and cold forging methods have their own limitations to produce such a complex shaped part; warm forging requires complex system with relatively higher manufacturing cost, while cold forging is not applicable to materials with limited formability. Therefore, multistage forging may be advantageous to produce complex shaped parts. In order to build a multistage forging system, it is necessary to characterize mechanical properties in response to system design parameters such as temperature, forging speed and reduction. For the analysis of formability of multistage forging process, finite element method(FEM) has been used for the process analysis. As a model case, a constant velocity (CV) joint forging process is analyzed by FEM, since CV joint has a complex shape and also its required dimensional tolerances are very tight. The data acquired by FEM is compared with operational forging data obtained from an industrial production line. Based on this comparative analysis, multistage forging process for CV joints is proposed.

• Tribology and Lubricants
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• v.24 no.5
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• pp.215-220
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• 2008

An internal friction model was developed to model the frictional behavior of automotive Constant Velocity (CV) joints by using the test data from an instrumented CV joint friction apparatus with actual driveshaft assemblies. Experiments were conduced under different realistic operating conditions of oscillatory speeds, CV joint articulation angles, lubrication, and torque. The experimental data were used to develop a physics-based semi-empirical CV joint internal friction coefficient model as a function of different CV Joint operating parameters. It was found that the proposed friction model captures the experimental results well not only the static behavior of friction coefficient, but also the dynamic friction terms, which is the main source of force that causes vehicle vibration problems.

• Tribology and Lubricants
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• v.28 no.6
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• pp.328-332
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• 2012

Generated Axial Force (GAF) due to internal friction at Constant Velocity (CV) joints is one of the causes generating vibration problems such as shudder in vehicle. In this study, the GAF measuring tester is developed to precisely measure GAF caused by internal friction in CV joints. As the developed tester can control temperature at joint, driving torque, angle of rotation and joint angles, actual driving conditions such as sudden acceleration can be applied to the machine. GAFs are measured and compared by using different types of grease in tripod housing. Also GAFs are measured for both new and used CV joints to be compared and analyzed. The test result shows the repeatability and consistency of the tester in terms of the different test conditions. By using the developed CV joint tester, friction performance of the joint can be evaluated by proposing the best CV joints as well as greases generating the lowest GAF.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.215.1-215.1
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• 2005

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.2
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• pp.382-392
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• 2004

The usage of constant velocity (CV) joint is effective for motorboats on gliding regime of the motion. During transition on the gliding when angle of the CV differs from null on driving and driven composite shafts there are moments of the second order. Excitation of oscillations of the second order moments occurs when driving shafts transmits a variable torque. which generates through CV joint a lateral moment acting on the bearing. As a result of oscillations from a resonating harmonic of a shafting the harmonic with the greater or periodically varying amplitude for power condition trough transferring to nominal power 144kW. Beating conditions coincide with third mode having frequency 45.486 Hz. In that case there is high increasing of the equivalent stresses. The forming of the stiffness of the composite material is concerned to use most orientation of the layer angle in the range of $\pm$60 degrees relatively of shaft axis. Application of that angles for layer orientation gives possibility to avoid high disturbance of the shafting for motorboat transition regime.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.211-214
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• 2006

The outer race of the constant velocity(CV) joint is an important load-supporting automotive part, which transmits torque between the transmission and the wheel. The outer race is difficult to forge, because its shape is very complex and the required dimensional tolerances are very stringent. Therefore, the internet based shape inspection system is developed in this study to provide quick and accurate data through the easy control from users. Proposed system uses mechanical displacement sensors to measure the shape of CV joint that has six inner ball grooves, and commercially available Lab-View program is used to process measured data into the dimensional shape. Developed program provides a simple user interface that enables users real-time access of data measured from industrial production lines. Furthermore, it can exchange measured data via the internet between users and forging system operators. A java applet helped the system connection via internet. A data, IP access, is transmitted to the packet by TCP/IP. Our proposed system has many advantages over current measuring systems including fast and efficient data processing by real-time control, and system flexibility.