48V 시스템 적용을 위한 랙 구동방식 조향시스템(R-MDPS) 개발

박수주(Suju Park),조형진(Hyeongjin Cho),유승범(Sungbem Yoo),이진우(Jinwoo Lee) 한국자동차공학회 2018 한국자동차공학회 부문종합 학술대회 Vol.2018 No.6

The automotive industry is confronted with regulations of fuel economy and demands of more electronic components which are for self-driving components and infotainment requirements. By replacing 12V with 48V System, not only we can expect a weight reduction but also a stable power supply. For these reasons, Automakers made a standard for 48V systems called LV148 and focusing on development with their parts supplier. In this paper, the development process of 48V R-MDPS was described and it is compared the basic performances and NVH of 48V R-MDPS with 12V R-MDPS in the condition of parts and a vehicle.

위상 최적화를 이용한 C-EPS용 메인 하우징의 경량화 설계

박수주(Suju Park),이순욱(Soonwook Lee),이승엽(Sungyup Lee) 한국자동차공학회 2018 한국자동차공학회 학술대회 및 전시회 Vol.2018 No.11

The C-EPS is an electric steering system in which the actuator that supports the driver"s steering force is located on the column. The main components are motor, ECU, sensor, reducer, main housing. Among them, the main housing plays an important role in determining the assembling position of the main parts such as the reducer, in addition to the function of simply protecting the internal parts. As a result, the rigidity and machining accuracy of the main housing affect system performance. In particular, the C-EPS with the low-rigidity main housing may degrade the NVH performance and system efficiency because the main housing is slightly deformed due to the reducer component generated when the motor operates at the maximum output. Thus, the main housings that are currently in production are heavily weighted to increase rigidity. In recent years, however, the automobile industry has been actively researching the weight reduction of automobile parts in order to improve fuel efficiency, and the need for lightweight design of C-EPS is also emerging. In order to lighten the main housing for C-EPS, researches on structural optimization have been carried out.

웜 샤프트 일체형 모터 적용 C-EPS 개발

이승엽(Sungyub Lee),박수주(Suju Park),이치호(Chiho Lee),박윤영(Yunyeong Park) 한국자동차공학회 2018 한국자동차공학회 부문종합 학술대회 Vol.2018 No.6

C-EPS is column type - Electric Power Steering system which is used to support driver’s steer force. In this system, Motor and Worm shaft generate support Torque and amplify torque. To use these separated two parts, connecting parts are also needed. Such as Bearings, Couplers, Rubber Couple ring, etc. Also cause of these connecting parts, Many side effect could occurs. Likewise, Price increase, Efficiency decrease, Increase reaction time. Worm Shaft Integrated Type Motor could be solution to these problem. In this article, We tried to demonstrate side effect of Worm shaft Integrated Type Motor. So We considered deflection of worm shaft, when reducer force applied. And we measured power fluctuation of single Motor, when shaft Axis is tilted. In addition, We used analysis program to analysis friction increase of whole C-EPS system, which might be affected by motor magnet force during shaft axis tilted. And also measured it too. In conclusion, Deflection of worm shaft and Motor’s power fluctuation is available to use. And increase of magnet force in tilted shaft axis doesn’t affect to friction of whole C-EPS system. So side effect of Worm Shaft Integrated Type Motor is reasonable to use in C-EPS. In addition, This type is needed to be verified in C-EPS System. Such as Noise, vibration and etc. And we will do these things in the near future.

상용차용 하이브리드 파워스티어링 조향시스템 개발

김봉수(Bongsoo Kim),이병윤(Byoungyun Lee),유승범(Sungbem You),박수주(Suju Park) 한국자동차공학회 2018 한국자동차공학회 학술대회 및 전시회 Vol.2018 No.11

Future technology trends of commercial vehicle steering components can be divided into three types. Environmentfriendly technologies for environment-related regulations such as reducing emissions and improving fuel efficiency, and technology for driving convenience using electric steering control systems, and safety technology to protect drivers, passengers, nearby vehicles and pedestrians. Large commercial vehicles require a high-power steering system that used engine-driven hydraulic pump systems (genally used min 120bar, 17Liter/min) compared to passenger cars. In recent technical trend, In order to improve fuel efficiency and realize autonomous driving technology, we designed EHPS and Motor driven electric control actuator with the same structure as C-EPS. Unlike the HPS system, the power used in the EHPS system is the motor, which rotates the gear pump to generate flow and pressure, and the steering oil is delivered to the ball nut gearbox to operate the power steering system through the pitman arm. The advantage of EHPS is that it does not use the engine drive torque, so it improves fuel efficiency by about 1%, and when the pump is connected in parallel, it can secure the flow rate to the main steering. In this process, it is difficult to realize the active autonomous driving technology of the vehicle itself through the steering angle control separately from the driver"s steering intention. Therefore, the motor control device directly connected to the steering wheel is essential, and we can design the actuator system by selecting the package and the required output according to the use conditions. The required steering torque as a general auxiliary steering was about 20 Nm, and the C-EPS type actuator using a worm reducer was manufactured and the performance evaluation was carried out. In this paper, we describe the construction process of the power steering system for commercial vehicles and the design process of the components.

SBW 시스템용 반력 장치 연구

김봉수(Bongsoo Kim),이승엽(Sungyub Lee),이정민(Jeongmin Lee),박수주(Suju Park) 한국자동차공학회 2019 한국자동차공학회 부문종합 학술대회 Vol.2019 No.5

Vehicle steering technology, which is currently being mass produced, uses a steering column to steer the wheels with the linear motion of the OBJ connected to the carrier using a motor-driven actuator connected to the steering column or rack gearbox. In this method, the driver"s manual torque is directly connected to the vehicle"s wheel based on the reliability of the structural connection of the mechanical device. However, in order to implement the active steering technology in the future, SBW is necessary. With the development of various sensors, the new steering technology of the vehicle has developed into the active steering technology of the vehicle by using the sensor for processing software of the recognition information, and the decision subject of the steering has been moved from the person to the ECU. Therefore, Unnecessary time of driver"s operating has increased and the steering column will be a device that measures the steering angle and provides a reaction to the driver in some situations where driver intervention is required. In the present situation that the driver has to intervene in a certain level of steering prior to the fully autonomous driving, in order to make the driver feel the current level of steering feeling for the products driven by the communication using the wire, not only securing the performance of the actuator, A reaction force column device capable of generating a steering feel of the steering wheel by the driving condition is required. In the case of the reaction force device, the motor torque is varied for each vehicle speed only for the purpose of assisting the driver. At this time, the column torque (Nm) sensed by the driver is measured, and this torque will be the reaction force in SBW. The reaction torque of SBW can be variously designed according to the type of reducer and conditions of use. As a result of the measurement, the system output is generally required to be 5Nm for a simple steering condition and 20Nm or more for a complete non-steerable condition.Therefore, the development direction of the reaction force system that can configure the SBW system and the review contents of the actual design for each new part are described.