• 한국자동차공학회논문집
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• 제6권2호
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• pp.54-66
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• 1998

In a passenger car automatic transmission, the gear ratio is determined by the combination of clutches and brakes, and each element of th planetary gear set is rotated or held stationary by the action of them. In this study, to investigate the shift characteristics of automatic transmission, the equations of motion are derived from the dynamic model of Ravigneaux type planetary gear set and solved analytically. The shift characteristics of each element of planetary gera set during gear ratio change are investigated by considering the torques and velocities of input, reaction and output elements.

• 한국생산제조학회지
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• 제22권1호
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• pp.29-35
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• 2013

The pitch reducer consists of several planetary gearsets, and they should have good load distribution over gear tooth flank and load sharing among the planets to improve the durability. This work investigates how bearing internal clearances influence both the load distribution over the gear tooth flank and the planet load sharing. A whole system model is developed to analyze a pitch reducer. The model includes non-linear mesh stiffness of gears, non-linear stiffness of bearings. The results indicate that the face load factor and mesh load factor decrease, and the fatigue life of output shaft bearings increase as bearing internal clearances of output shaft decrease. Therefore, the internal clearance of output shaft bearing must be considered when designing the pitch reducer for wind turbines.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권5호
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• pp.253-259
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• 2005

Magnetic encoder with relatively low pulse per rotation is generally used for detecting speed of the high-speed rotating machine. It is due to the fact of the mechanical problems of vibration and bearing stiffness and also the limit of maximum output pulse of the mounted encoder. The magnetic encoder is divided into two types, that is, toothed gear-wheel method and magnetic wheel method according to the shape of the rotation disk. In case of detecting speed by the tooth gear-wheel, the encoder itself can be acted as the additional inertia where the number of tooth determining the output pulse and the width of the wheel detecting the change of the magnetic flux density are relatively enough large considering the volume of the rotating machine. While the magnetic wheel method has the limit of the magnetizing number of the ring magnet, there is relatively few, if nv, the influence of inertia on the machine. In this paper, it is proposed a simple magnetic wheel encoder suited for the high speed rotating machine and the method of signal processing and the output characteristics are examined through the V/F operation of max 48,000(rpm) and 2.4(KW) spindle motor.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제48권11호
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• pp.646-654
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• 1999

This paper deals with PWM patterns for harmonic reduction in inverter fed traction motors and the gear changing techniques for the variable speed drive of traction motor. GTOs are used as switching device of inverter because traction motor is a large load. To derive PWM rattern which can minimize the harmonics with the limited switching frequency, the output current and torque characteristic of SPWM and SHE PWM was analyzed. GTO inverter used for traction motor drive includes harmonics in the output current and torque by the limitation of switching frequency. However, the hybrid PWM method that adopt SPWM in the range of low frequency and SHE PWM in upper frequency range can achieve less harmonic characteristics in GTO inverters. If the traction motor is driven in variable speed by the proposed PWM pattern, 7 times of gear changing is needed. At the instant of the mode change, magnetic flux and torque may be altered and the large current flow. To reduce such an undesirable transient behavior, it is also presented the technique for the gear changing of inverter fed traction motor drive operated with the hybrid PWM. The results are verified by simulations and experiments.

• 풍력에너지저널
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• 제15권1호
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• pp.43-49
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• 2024

This study performed a response analysis according to the transmission error of the yaw drive. To perform the response analysis, the excitation source of the transmission error was modeled and the outer ring of the first stage bearing and the outer ring of the output shaft bearing were used as measurement positions. The response results were analyzed based on the vibration tolerance values of AGMA 6000-B96. As a result of the response of the first stage bearing outer ring, the maximum displacement of the first stage planetary gear system was 5.59 and the maximum displacement of the second to fourth stage planetary gear systems was 4.21 ㎛ , 3.13 ㎛ , and 25.6 ㎛ . In the case of the output shaft bearing outer ring, the maximum displacement of the first stage planetary gear system was 1.73 ㎛, and the maximum displacement of the second to fourth stage planetary gear system was 1.94 ㎛, 0.73 ㎛, and 2.03 ㎛. According to AGMA 6000-B96, the vibration tolerance of first stage is 17.5 ㎛, and the vibration tolerance of the second to fourth stages is 58 ㎛, 80 ㎛, and 375 ㎛, which shows that the vibration tolerance is satisfied and it is safe.

• 한국소음진동공학회논문집
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• 제22권1호
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• pp.46-52
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• 2012

Since the engine and reduction gear in a naval vessel are usually supported by the mounting system separately, the misalignment between the input shaft of the reduction gear and the output shaft of the engine should occur caused by ship motion. In this study, this misalignment is estimated from the linear static analysis assuming that the phase of movements of the engine and reduction gear at low frequency range is same and the dynamic effect is not affect to them. Through comparing the relative displacement of the engine and reduction gear calculated from linear static analysis to that from dynamic analysis as well as experiment, the assumption in this study could be verified.

• 동력기계공학회지
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• 제14권3호
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• pp.64-70
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• 2010

In this study, designing of precise linear transferring device which can be applied to industrial machine and robot industry has been introduced. The direction of power flow and output feature are similar to current Rack-Pinion type. However, unlimited length extensity via rack modulizing, and securing high velocity transportation have been realized by applying Pin-Pinion Gear type at the operation part. The analysis has been calculated to obtain the Pin-Pinion Gear's optimized tooth profile. As a result of research, it is impossible to control precisely even overlap at the teeth of involute and sprocket. Because they have peculiar gearing structure. Therefore, modified cycloid tooth has been proposed to perform high velocity, precise control without backlash.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2010년도 춘계학술대회 논문집
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• pp.65-66
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• 2010

To improve the gear noise quality, gear tooth grinding machine are widely used in automotive industry. While using the gear profile grinding machine to improve the gear tooth quality of the transmission, several defects such as chattering, tooth waves that cause the gear noise occasionally happened. But it is very difficult to solve that problem, because there is no one who knows the setting up the optimal grinding condition appropriately. The abnormal manufacturing conditions which make the gear noise make the engineer to spend a lot of time, effort, and money. Due to demands for solving the serious abnormal gear noise happened in the new FF 6th stage automatic transmission in the mass product stage, the vibration checking process in the worm wheel axis, work rotation and fixed axis of the grinding machine were adapted to find the root causes. As a result, gear profile wave are affected by the work rotation axis's unbalance which is caused by worm wheel feeding speed. And a primary and the secondary grinding feeding speed, cutting oil, work fixed forces are also proved as the important factors. After setting up the grinding condition reported in this paper, it was adapted successfully to the grinding machine to manufacture the new FF 6th speed automatic transmissions' output gear. The gear noise was dramatically disappeared and the process and results will offer good guides to the engineers who manufacture the gear with the grinding machine.

• 한국기계가공학회지
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• 제13권5호
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• pp.8-14
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• 2014

A slewing reducer consists of two planetary gearsets which require a good load distribution over the gear tooth flank for enhanced durability. This work investigates how the bearing characteristics influence the load distribution over the gear tooth flank. A complete system model is developed to analyze a slewing reducer, including the non-linear mesh stiffness of the gears and the non-linear stiffness of bearings. The results indicate that the type, arrangement and preload of the output shaft bearings greatly influence the gear mesh misalignment, contact pattern, face load factor, gear safety factor and lifetimes of the parts.

• 드라이브 ㆍ 컨트롤
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• 제12권4호
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• pp.28-34
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• 2015

Because heavy-duty construction vehicles such as excavators are required for good engine-room cooling capacity, a hydraulic gear motor is adopted in the cooling fan drive mechanism to actively control the output speed, instead of adopting the conventional ON/OFF type belt drive. While gear motors are normally limited to 140bars of operating pressure, those for the cooling fan are capable of operating at continuous pressures of up to 220bars. After assembly, all gear motors for high pressure must pass an aging test which is a kind of the wearing process between the gear teeth and motor housing. During the aging process with gradual pressure increments, gear sticking sometimes occurs due to abnormal wear, resulting in defects. This paper focuses on a gear-sticking free aging test controller that is designed together with the knowledge of an experienced operator and the analysis results of experimental data of the gear jamming phenomenon. From the aging experiment, it is demonstrated that the developed controller that can alter the setting pressure of the load pump is effective for stabilizing the abrupt increase in the motor input pressure, thus preventing the hydraulic motor from stopping. This is expected to be helpful for the reduction of defects and increase in productivity.