• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.6
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• pp.205-215
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• 1996

In this paper, the performance analysis of the vehicle with the Ravigneaux type automatic transmission has been carried out using information of engine and drivetrain. It is necessary to understand the overall system including engine, torque converter, clutch, planetary gears, and road load. The equations of motion are derived from dynamic model. The GUI computer simulation program has been developed to analyze the powertrain performance of the vehicle with the Ravigneaux type automatic transmission.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.10
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• pp.36-45
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• 1996

The precise estimation of the reliability and life of the Ravigneaux planetary gear train used in an automatic transmission is necessary in order to enable accurate material and geometric properties to reliability distrobution and the number of load cycles at failure. These are critical for the proba- bilistic design of complex planetary gear system as Ravigneaux type particularly during various gear ratios. The Ravigneaux planetary gear train has five gears, such as a forward and a reverse sun gear, a short and a long pinion, and an annulus gear. In this paper, the Ravigneaux gear system is analyzed to figure out the reliablity distribution. i.e. the probability of survival in the system without its overhaul. First, the reliablity method based on the Weibull distribution is used in conjuction with the Palmgren's model to predict both the individual reliabilities of its components and the nimber of load cycles when the system failed. Then using the presented method, the life of the Ravigneaux gear system can be determined. Alwo the different design parameters such as tooth face width, material property, and Weibull exponent are applied and reached to optimal ones. Thus, the precise evaluation of the reliability and life of the Ravigneaux planetary gear train used in an automatic transmission can be effectively carried out.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.11
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• pp.1943-1949
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• 1997

In this paper, the analysis of the shift transient characteristics for the Ravigneaux type automatic transmission has been carried out using dynamic models of the automatic trnasmission. It is necessary to understand the overall system including multi-plate clutch, band brake, one way clutch, and planetary gears. The equations of motion are derived from the dynamic models of the automatic transmission. The GUI computer simulation program has been developed to analyze the shift transient characteristics of the vehicle equipped with the Ravigneaux type automatic transmission.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.3
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• pp.49-58
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• 2019

Automatic transmissions are standard equipment in most automotive vehicles because they provide smooth speed shifting and a compact design with multiple speed ratios. Their structure consists mainly of planetary gear sets as power-transmitting devices and brakes and clutches as shifting devices. Several forward and one reverse speed ratios are achieved by actuating shifting devices to connect gears, input and output shafts, and the transmission case. In the development of a new transmission, kinematic configurations reflecting the transmission concept design are required, and the ability of the new concept design to be assembled without any interference among the connections must be demonstrated. In this study, an assemblability analysis of the kinematic configurations of a Ravigneaux-type automatic transmission was conducted with an assemblable example of an 8-speed Ravigneaux-type automatic transmission.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.263-266
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• 2001

The performance of the powertrain can be analyzed using dynamic models including transient characteristics, and the equations of motion can also be derived from the dynamic models of the powertrain. In this study, the shift transient characteristics of the vehicle equipped with Ravigneaux type planetary gears automatic transmission has been investigated.