• Journal of Power System Engineering
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• v.16 no.6
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• pp.66-72
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• 2012

The parking brake embedded in track driving motor for driving an excavator is composed of wet type multi-friction discs. This type parking brake can be designed more compact because the combination of some sheets of friction discs generate great braking power, and also it has good braking characteristic and long life time because it works in the oil. In this study, we analyzed torque characteristic of the parking brake through simulations and performed experiments by use of 3-kinds of paper friction sheet manufactured by different pressing methods. And, we compared the maximum static friction coefficient and torque characteristic with the simulation results and confirmed the optimal manufacturing process through this result.

• Journal of Power System Engineering
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• v.16 no.2
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• pp.5-10
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• 2012

The parking brake is one of the essential units embedded in track driving motor for forward and backward motion of an excavator. It is composed of multi-friction discs. When the hydraulic motor stops, the multi-friction discs closely stick to the facing discs by acting of multi-spring forces. So, the friction forces generate the braking force by compressing the cylinder barrel of hydraulic motor. In this study, we combined the multi-friction discs to two kinds of spring which have different spring force, and the maximum torque measured at the rotational starting point of hydraulic motor through gradually increasing the rotational torque of load side hydraulic motor by use of 1 and 2 sheets of friction plates. And, under this experimental condition, the maximum coefficient of static friction and the characteristics of paper friction sheet were analyzed. The obtained experimental results will be applied to the design of parking brake system for producing large size excavator in the 85-ton weight class.

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.1836-1837
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• 2006

본 논문에서는 차량용 전자제어식 주차 브레이크(Electric Parking Brake, EPB) 시스템의 고장 허용 제어(fault tolerant control)를 위한 고장 안전 기법(fail-safe logic)을 제안한다. 고장 안전 기법의 구현을 위하여 EPB 구동 모터에 흐르는 전류 리플을 측정하여 센서리스 위치 추정을 한다. 추정값과 홀 센서의 출력을 비교하여 잔차(residual)를 발생하고, 이를 이용하여 시스템 내부의 고장을 진단하고 고장 안전 기법을 통하여 전체 시스템의 오작동을 방지한다. 시스템 오작동을 방지하기 위한 고장 안전 기법에 대하여 정의하고 모의실험을 통하여 내부 시스템의 고장이 발생 시 이 기법이 고장을 진단하고 시스템을 안전하게 운영할 수 있음을 확인하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.94-98
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• 2013

Transfer Path Analysis (TPA) is commonly used, by car makers and parts suppliers, analysis process to root the cause of NVH problems. In general, TPA is an analyzing technique to find the contributing factors of noise/vibration problems, and their transfer path in vehicle. However, not only TPA is used to analyze the source of NVH problems but also is used to predict NVH performance prior to the proto vehicle, or to set the development target for next new vehicle. Automotive parts manufacturing companies have to set NVH performance target when developing new systems just as car makers have NVH target set for new vehicle. Nevertheless, most of components are currently being developed based on subjective evaluation without an objective target. To judge the suitability of using TPA to set NVH target of electric parking brake, this research analyzed the transfer path by setting them in two points of view; Chassis Module and Electric Parking Brake, and comparing the measured value and calculated value. From this result, NVH target of electric parking brake will be approached in level of vehicle, system and component.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.11
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• pp.977-982
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• 2015

This study uses finite element analysis to evaluate the forming load of tool entrance angle of the cold forward extrusion molding process of helical gear; this can replace the spur gear applied to the Electronic Parking Brake (EPB) system. A cold forging process is often used in the automobile industry as well as in various industrial machines due to its high efficiency. Finite element analysis is frequently used when interpreting results of the forging process. Formality was evaluated by calculating tooth profile filling rate of helical gear. Change in required forming load was investigated when the entrance angle of forward extrusion tool die was changed from $30^{\circ}$ to $60^{\circ}$, also by finite element analysis. We suggest suitable tool entrance angles.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.3
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• pp.119-125
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• 2012

Caliper intergrated Electric Parking Brake (EPB) is an automatic parking brake system, attached to rear caliper. Because EPB uses luxury vehicles recently, the drivers of vehicles are sensitive to the EPB noise. EPB is operated by the motor and gear, so noise is generated by motor and gear. In order to reduce noise, One of EPB manufacturers uses helical gear and changes the shape of EPB housing. But these methods are not optimized for reduction of interior noise. There are many noise transfer paths into vehicle interior and it is difficult to identify the noise sources. Therefore, in this study, we performed contribution analysis and modal testing in the vehicle system. It is possible to distinguish between air-borne noise and structure-borne noise in the vehicle interior noise by comparing interior noise peak with resonance mode map.

• KIPS Transactions on Software and Data Engineering
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• v.6 no.4
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• pp.167-176
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• 2017

There are increasing policies and safeguards to prevent various human resource losses with the development of automotive industry. Currently ISO26262 $1^{st}$ edition has been released in 2011 to ensure functional safety of electrical and electronic systems and the $2^{nd}$ edition will be released in the second half of 2016 as part of a trend. The E/E (Electrical & Electronics) system requirements verification is required through walk-through, 인스펙션, semi-formal verification and formal verification in ISO 26262. This paper describe the efficiency of model checking for the E/E system requirements verification by applying the product development project of ASIL (Automotive Safety Integrity Level) D for the electrical parking brake system.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.5
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• pp.26-30
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• 2009

In this paper, a robust model based fault detection for varying temperature is proposed, To develop a robust force estimation model, it needs temperature information because the force sensor's output is affected by a temperature variation. If an EPB system does not include a temperature sensor, the model has a much larger error than an EPB system with a built-in temperature sensor. Therefore, the temperature is estimated by using Ohm's law. The force model is applied with a motor current, battery voltage, operation mode, and the estimated temperature to detect a force sensor's abnormal signal fault. The residual is calculated by comparing the value of the measured force and the estimated force. Fault information is collected by using the output of the evaluated residual with the adaptive thresholds. A proposed robust model based fault detection for varying temperature was verified by HILS (Hardware in the Loop Simulation).

• 기계와재료
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• v.22 no.3
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• pp.88-95
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• 2010

국내외 대형 플랜트사업이 활발해지면서 여기에 소요되는 건설기계의 수요가 급증하고 특히 초 대형화가 요구되고 있다. 그러나 국내 건설기계는 장비중량이 40ton 이하인 것을 주로 생산하고 있었으나, 최근 이것에 2배가 넘는 85ton급 초대형을 생산하고 있다. 주행모터(track motor)는 굴삭기의 전진 및 후진 주행을 하는 핵심 부품으로서 유압카운터 밸런스 밸브, 양방향작동 릴리프밸브, 주차 브레이크 장치, 2속 제어장치, 유압모터와 고 강성 유성기어감속기가 매우 콤팩트한 구조로 구성된다. 우리나라에서는 두산모트롤, 제일유압, 선진정공 등에서 40ton 이하의 중소형 건설기계용 주행모터를 생산하고 있으나, 70ton 이상 초대형 급은 일본 Kayaba사, Kawasaki사, 독일 Rexroth사 및 이태리 Trasmital사 들로부터 전량수입에 의존하고 있다. 본고에서는 건설기계의 핵심부품인 주행모터의 국내외 수요시장 동향을 분석하여 국산화 개발필요성을 강조하였고, 특히 초대형 주행모터의 성능특성을 분석하여 국산화 개발에 반영 할 수 있도록 하였다.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1525-1527
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• 2008

기존 케이블 puller 방식의 EPB 시스템은 제동력을 측정하기 위하여 hall effect force 센서를 이용하고 있다. 그러나 본 논문에서는 hall effect force 센서를 사용하는 대신 모터의 속도를 이용하여 제동력이 가해지는 시점을 결정한 이후 모터의 회전수에 따른 제동력 추정 기법을 제안하고 실험을 통하여 검증한다.