• Journal of Mechanical Science and Technology
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• 제14권5호
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• pp.508-517
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• 2000

For shift quality improvement, torque sensors are currently too expensive to be used on production vehicles. To achieve smooth acceleration shift, the reference trajectory of the clutch slip speed for accomplishing the shift process within a designated shift completion time and its relationship with the clutch actuating torque were suggested by Jeong and Lee (1999). In order to facilitate the proposed algorithm, nonlinear estimators for necessary information such as the axle shaft torque, clutch friction and turbine torque were designed using only speed sensors. Accounting for the modeling error, a control law for this indirect smooth shift was proposed based on the above mentioned suggestions. Simulation results of the proposed estimators and shift controller were presented and further considerations for practical applications are discussed.

• 한국생산제조학회지
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• 제20권6호
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• pp.692-696
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• 2011

A clutch is a very important component when engine starts and gear shifting is needed. The clutch the most commonly used is the dry clutch. This type of clutch has pads, and they are worn after disengagement of clutch little by little. The characteristics of the clutch changes as these pads wear, so wear needs to be measured, and the clutch should be controlled for proper operation. In this study, the clutch contact point estimation algorithm has been developed. From this algorithm, clutch force map changes depending on wear, and the clutch operates properly. We also see the shifting transient of a vehicle for drivability with throttle valve position control and synchronizer movement.

• 한국안전학회지
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• 제25권3호
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• pp.15-21
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• 2010

A differential case equipped with LSD(limited slip differential) has several advantages over a normal type for rear wheel drive vehicles. Specially, the torque distribution can be done between left and right drive wheel in the state of limited slip differential. Also although LSD types are very various according to operating type, medium and torque distribution, a multi-clutch type is generally applied to rear wheel drive vehicles. So, this study presents the analysis of design parameters for development of a friction plate for multi-clutch type LSD using vehicle road test, the simulation of analytical model and the development of vehicle dynamics model by a benchmark product. According to this investigation, the design parameters which are pre-load of coil spring, friction plate and contact area quantity, friction coefficient and TBR(torque bias ratio) for a friction plate are derived from experiment and simulation and consequently, vehicle dynamics model has been constructed for the development of friction plate for multi-clutch type LSD.

• Journal of Advanced Marine Engineering and Technology
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• 제41권4호
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• pp.330-336
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• 2017

본 연구는 고무 탄성커플링을 적용한 특수선의 디젤엔진 추진체계에서 유압작동식 다판, 습식 마찰클러치의 고착에 대한 원인분석 내용이다. 클러치 고착원인 분석을 위해 피쉬본((fish bone) 방법으로 클러치 및 감속기어 분해조사, 선박 탑재상태에서의 체계 시험 및 부품 조사, 비파괴 시험 등을 통해 수행하였다. 마찰판 고착은 클러치 중공축의 크랙부를 통해 제어오일 누설로 인한 슬립, 마찰열 발생에 의해 발생되었다. 마찰판 냉각 오일 또한 크랙부를 통해 동시에 누설에 기인한 유량부족으로 클러치 마찰판은 국부적인 눌러붙임이 발생하는 핫스팟(hot spot)에 의해 고착되었다.

• Advances in Automotive Engineering
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• 제1권1호
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• pp.21-39
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• 2018

Clutch energy is the thermal energy dissipated on the clutch disc, and it reaches its highest level during drive-off as a result of the difference between the angular speeds of the flywheel and clutch disc, and the torque transmitted. The thermal energy dissipated effects the clutch life. This study presents a new drive-off and thermal model to calculate the clutch energy for a rear wheel driven heavy-duty vehicle and to analyze the effects of clutch energy on temperatures of clutch pressure plate, flywheel and clutch housing. Three different driver profiles are used, based on the release of the clutch pedal in modulation zone: i) the pedal travels with the same speed all the way, ii) the travel speed of the pedal increases, iii) the travel speed of the pedal decreases. Vehicle test is performed to check the accuracy of the model. When compared to a simpler model that is widely used in the literature to calculate the clutch energy, the model used in this study calculates the clutch energy and angular speed behaviors of flywheel and transmission input shaft in better agreement with experimental results. Clutch wear and total clutch life are also estimated using the mean specific friction power.

• 한국자동차공학회논문집
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• 제14권1호
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• pp.54-59
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• 2006

An analytical solution for deflection-load characteristics of a conical disk spring used especially in the automotive manual transmission clutch applications is proposed in order to take into account the effects of friction and large deformation. The conical disk spring, or the diaphragm spring, has a hinge support, an application point of release load at the tip of the fingers and an application point of clamp load near but inside the outer perimeter of the conical disk spring. The friction coefficient is assumed to be a constant regardless of the speed of deflection and the magnitude of loads. Comparison with experimental shows a good agreement with the analytical prediction. Also, the sensitivity of the clamp load due to variations in the geometrical parameters of the conical disk spring is calculated and discussed.

• International Journal of Automotive Technology
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• 제7권1호
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• pp.61-68
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• 2006

In design of the friction clutches of automobiles, knowledge on the thermo-elasticity a priori is very informative in the initial design stage. Especially, the precise prediction technique of maximum temperature and stress should be requested in design of mechanical clutches for their durability and compactness. In this study, an efficient and reliable analysis technique for the design of the mechanical clutches by using computer modeling and numerical method was developed. A commercial software STAR-$CD^{TM}$ was used to find the convective heat-transfer coefficients. MSC/$NASTRAN^{TM}$ software was followed to predict the temperature of clutch with utilization of estimated coefficients. Some experiments were also performed with a dynamometer to verify the procedure and calibrate the thermal load. As a conclusion, a design procedure, including numerical steps and experimental techniques for calibration, was proposed.

• 한국자동차공학회논문집
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• 제3권3호
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• pp.79-89
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• 1995

Rattle noise occurs at manual transmission as idling and driving of a automotive. It can be solved by torsional characteristics of a clutch disc. A clutch disc consist of a region of pre-damper and main-damper. Rattle noise is affected by pre-damper and main-damper equipped for a torsional spring and friction washer. Pre-damper range covers noise radiating from manual transmission when engine is idling and main-damper range covers noise when engine is driving. The aim of this reserch is to clear transmission rattle noise by way of torsional characteristics of a clutch disc. The experiment is carried out as idling and driving of a automobile equipped for 1.5L MPI engine, dry single-disc type clutch and manual transmission. In this study, the results show for a vibration of manual transmission as idling and driving can be cleared by a clutch disc of Pre-damper type.

• 드라이브 ㆍ 컨트롤
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• 제19권2호
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• pp.17-26
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• 2022

Recently, automatic transmissions caused a good improvement in the shift quality of a forklift. An advanced shift control algorithm, which was based on TCU firmware, was applied with embedded control technology and microcontrollers. In the clutch-to-clutch shifting, one friction element is released and the other friction element is activated. During this process, if the release and application timings are not synchronized, an overrun or tie-up occurs and ultimately leads to a shift shock. The TCU, which measures only the speed of the forklift, inevitably applies the open-loop shift control. In this situation, the speed ratio does not change during the clutch fill. The torque phase occurs until the clutch is disengaged. In this study, an offline shift logic of the learning control was proposed. It induced a synchronous shift when the learning control progressed. During this process, the reference current trajectory of the release clutch was corrected and applied to the next upshift. We considered the results of the overrun/tie-up characteristics of the upshift performed immediately before. The vehicle test proved that the deviation in shift quality, which was caused by the difference in the mechanical characteristics of the clutch, could be improved by the learning control.

• Tribology and Lubricants
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• 제20권6호
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• pp.299-305
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• 2004

The wear properties of clutch facing materials with two different copper amounts were evaluated against the fly-wheel materials used in clutch system, such as gray cast iron and spheroidal graphite cast iron. Sliding wear tests were carried out for four different combinations with these clutch facing materials and flywheel materials at different speeds and applied loads. Results showed that the clutch facing material contained a higher copper amount had the better wear resistance. And using the gray cast iron as the counter material, clutch facing material resulted in the much lower wear rate, regardless of the copper amount. It is obvious that the wear properties of clutch facing material are influenced from the thermal conductivities of the clutch facing material and the counter material.