• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.8
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• pp.592-599
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• 2014

A torsional vibration at driveline happens seriously at rapid vehicle acceleration. The torsional vibration at driveline can be reduced by optimization of joint angle and yoke phase angle of driveline. But, the joint angle of driveline is changed according to vehicle driving condition as acceleration, deceleration, forward and backward driving, so that excessive vibration is transmitted to vehicle body at specific driving condition. Especially under rapid acceleration condition, vibration transmitted to body could be maximized because excitation force at rapid acceleration is bigger than that at normal driving condition due to changed joint angle. The torsional vibration of driveline can be kept at low level by controlling suspension parameter to minimize rigid axle displacement as well as optimizing joint angles considering the vehicle acceleration condition.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.9 s.90
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• pp.837-845
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• 2004

A variable friction damper for vehicle driveline has been proposed. This new torsional damper system uses a solenoid as an actuator to vary friction force of the damper. To verify the idea of using a solenoid in a variable damper system, the test fixture and the dampers are made and tested. Also, to find out the range of damper friction forces that influence the vehicle driveline vibration, a mathematical model of the driveline had been developed and simulated. Test and simulation results show that, within electric current used in the vehicle electric system, the solenoid can develop enough friction force that will surpass resonance in the driveline of 1.5 L Gasoline engine vehicle during acceleration.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.2
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• pp.48-57
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• 1997

A computer aided analysis and design system is developed for analyzing the driveline torsional vibration of a vehicle. Torsional vibration characteristics of driveline component are investigated and 10 types of module are developed. They can be connected together to represent any driveline configuration. During assembly process simulation program is generated. It is implemented using C++language. A driveline tor- sional vibration system at full load driving condition and idle rattle system are modeled and simulated with this system. Their responses for engine torque excitation are evaluated on time and frequency domain, and the results are compared with test results favorably. This system makes it simpler and easier for design and analysis engineer to model and analyse the driveline system.

• Transactions of the Korean Society of Automotive Engineers
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• v.25 no.3
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• pp.360-366
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• 2017

In commercial vehicles such as frame-based mid-size trucks, it is easy to reduce vibration caused by driveline with the cab mount system. There are no critical driveline vibration problems associated with these vehicles up to now. However, in the case of a similar grade of monocoque type mini-bus, there are no effective vibration isolation components such as a cab mount. Vibration caused by driveline is quite a complex problem to understand in terms of which part governs the phenomenon and how the problem can be solved. Thus, we have to manage the design factor about the driveline and mount system strictly at the early stage of vehicle development. Low frequency vibration caused by the driveline system is investigated in this study. We created the CAE driveline model and analyze low frequency vibration. Then contribution analysis about each design factor of driveline and mount system is performed. Finally, we can obtain the optimized design factor for a driveline system of a mini-bus, which is verified by the vehicle test results.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.5
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• pp.140-146
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• 2008

A friction damper is installed in the passenger car driveline in order to dissipate the torsional vibration energy. The frictional damping hysteresis has considerable influences on the driveline vibration characteristics and, therefore, it is one of the most important parameters in the damper design. To investigate the hysteresis effects on the driveline vibration, a dynamic model of the passenger car driveline with manual transmission has developed, and simulations were executed on the several different driving conditions for various hysteresis values. To verify the model, vehicle tests are preformed and the test data were compared with the simulations results. The simulation and test results show good agreements and the model could be used to determine the optimal hyteresis values in early design stage of the damper.

• Journal of Biosystems Engineering
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• v.31 no.4 s.117
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• pp.323-333
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• 2006

Introduction of a direct engine-PTO driveline to agricultural tractors has reduced production cost and increased transmission efficiency of the PTO driveline. However, this type of PTO driveline has caused a severe rattle noise in the PTO gearbox under idle conditions. This study was conducted to investigate the causes of the rattle noise and the effects of driveline parameters on it. A mathematical model was developed for a direct engine-PTO driveline. The model was proved experimentally to be accurate enough to simulate the dynamic characteristics of the PTO driveline motions. The simulation study showed that the rattle noise was caused by collisions between the driving and driven gears in the PTO gearbox due to velocity variation of the gears, which was induced by torque fluctuations from the engine. It was also found that the rattle noise decreased with the drag torque and mass moment of inertia of the engine flywheel. Smaller mass moment of inertia of the driven gears and backlash also reduced the rattle noise. However, increasing the drag torque and mass moment of the engine flywheel or decreasing the backlash and mass moment of inertia of the driven gears were limited practically by their detrimental effects on transmission efficiency, gear strength and smooth meshing of the gears.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.10
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• pp.24-30
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• 2020

The high speed of an engine balance box may cause significant additional gear noise. Gear accuracy is the most useful key to reduce gear noise, but the small tooth width and thin-walled anti-backlash gear introduce challenges to the manufacturing process. In order to reduce the gear noise caused by gear pitch error, this paper investigates the correlation between influencing factors and gear pitch error by analyzing the processing technology, tooling fixture, and equipment accuracy. By improving the process and optimizing the gear design, the gear machining accuracy was improved and the processing cost was saved.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.2 s.95
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• pp.183-193
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• 1999

In the previous study, a module-type vibration analysis system using modular approach is developed for the purpose of analyzing the torsional vibration of vehicle driveline. In the present paper, the system is utilized to investigate the torsional vibration of the driveline of a middle duty truck. The driveline with driving condition is modeled and the torsional vibration response is simulated. The resonance 45Hz is found at engine speed 900rpm and the resultant vibration is very high. It shows favorable agreements with reference data. The effects of parameter change on torsional vibration are also investigated, so it is clarified that clutch characteristics, axle shaft stiffness are very influential on reduction of vibratio. So the countermeasure is proposed for the clutch characteristics. The reduction of torsonal vibration by 8rad/sec is obtained.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.12
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• pp.109-119
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• 1995

A driveline incorporating universal joints when driving through an angle can excite various components in a vehicle with second order excitation of torsional and bending vibrations, being transmitted either audibly(noise), or physically(vibration). For a certain range of vehicle dpeed noises can be radiated from the cab wall, in which resonances occur by the excitations transmitted from the driveline as a vibration source. In this paper, the excitation mechanism of cab noises is studied especially for the vehicle speed range of 65 .approx. 75 km/h through the simulation for torsional vibrations of the driveline and for bending vibrations of the cab of an 11 Ton grade Cargo Truck, and verified additionally by vibration and noise measurements. As a result, it is found that the uncomfortable noises in the cab are caused mainly by the abrupt increase of the joint angle of driveline near the axle differential resulted from the excessive clearance alignment of the leaf spring gate.

• Journal of Biosystems Engineering
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• v.22 no.1
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• pp.1-10
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• 1997

A ratio of cosine values of two intersection angles in a tractor-rotary power driveline was established as a design criterion which must be satisfied in the range of vertical movement of the rotary with respect to the tractor. In addition tractor-rotary power driveline was analyzed and 25 design variables were Proposed. The intersection angles were also derived using the design variables. Using the design condition and variables, a computer program was developed to evaluate the performance of the driveline and to simulate the vertical movement of rotary. Several methods for searching the optimum design were also suggested.