소형무장헬기용 20mm 포탑형 자동포체계의 송탄장치에 관한 연구

오형용 경상대학교 융합과학기술대학원 2021 국내석사

The feeding system is a sub assembly of the 20 mm TGS(Turreted Gun System) for a LAH(Light Armed Helicopter). The function of the feeding system is to supply the ammunition at an appropriate speed during the operation of an automatic gun system in a 20 mm TGS. This paper introduces a new feeding system, and discusses in detail its design and the tests in different setups that replicate the motion of helicopters. 연구 대상인 20mm 송탄장치는 20mm 포탑형 자동포체계의 하위구성품이며, 한국형 소형무장헬기에 사용될 목적으로 개발되었다. 송탄장치는 포탑형 자동포체계의 자동포가 원활히 사격될 수 있도록 적절한 속도의 탄약 공급 기능을 제공한다. 본 논문에서는 송탄장치의 연구목표 및 설계 내용을 기술하였으며, 설계를 바탕으로 제작된 모델을 헬기 기동 자세를 고려한 장치에 장착하여 시험을 실시하고 그에 대한 결과를 함께 소개한다.

이퀄라이징 스러스트 베어링 성능 검증을 위한 정적 미스얼라이먼트 시험에 관한 연구

나태호 경상대학교 융합과학기술대학원 2019 국내석사

The perfect alignment condition was always difficult to rationalize. Because of the lack of reliable experimental data based on the theory, this study verified the performance by performing misalignment experiments of equalizing thrust bearings. Bearing unit load, temperature and film thickness were measured by tilting 0.1 and 0.15 degrees with the bearing in alignment. The temperature and load were increased linearly proportional to all thrust pads, although there was a certain temperature distribution difference due to the asymmetric load. In operation, bearing temperature is an important factor and is highly influenced by rotational speed. Therefore, in this study, additional 500, 600 rpm tests were performed and temperature was compared at 700 rpm. As the rotational speed increased, the maximum and minimum temperature differences of the bearings increased linearly. This makes it possible to predict the temperature of the bearing under various conditions. In this experiment, the equalizing thrust bearings in some misalignments satisfied their performance within the safe range.

항공기 주익 조립 장비의 드릴링 및 스웨이징 성능에 관한 연구

홍성민 경상대학교 대학원 2018 국내박사

Currently, the aerospace industry is investing heavily in automation equipment to reduce production costs, shorten production time, and improve quality under the leadership of Airbus and Boeing. In particular, there is a need for equipment that automatically performs drilling and riveting, which is a significant part of the aircraft assembly process. However, due to lack of know-how on automation process and technology for automation equipment development, various problems occurred in commercialization process. The equipment to be developed through this study is a Drilling and Riveting Machine(DRM), which automatically connects a lock bolt by drilling and swaging in an aircraft assembly process. When DRM development is completed, it is expected to produce products with high level of precision and quality compared with existing manual processes. Also, it is anticipated to be possible to secure price competitiveness and reduce maintenance cost by shortening the process time. However, in Korea, there are no precedent cases where equipment that can drill and rivet simultaneously were ever developed and produced. Therefore, in this study, we try to find out the problems that can occur in the process of commercializing DRM and find ways to improve it. First, the precision of the hole diameter and the length of the exit burr have a great influence on the quality of the finished product. Therefore, a test bench is manufactured to evaluate DRM drilling performance. The drill diameter and the length of the exit burr according to the rpm of the drill spindle of the DRM are measured and the process capability evaluation is performed to confirm whether the criterion is satisfied or not, Second, we predict the shape of the swaged collar by numerical analysis on the process of collar swaging in the rock bolt, cut the coupon swaged by DRM and compare it with numerical analysis results. The tensile load test was then performed to confirm the bond strength between the rock bolt and the swaged collar, and through the fatigue test, trying to predict the fatigue limit and fatigue life while they are in the fretting state. If the equipment is operated under those conditions derived from this study, it is expected that efficient operation will be possible with performance, durability and economic efficiency.

앤드캡 타입 볼 순환구조의 곡률 변경에 따른 볼스크류 성능 향상에 관한 연구

양채윤 경상대학교 대학원 2018 국내석사

Recently, there is an increasing demand for high performance, high precision ball screws from the machine tool field to the vehicle and aerospace industry. As described, the ball screw is applied to various fields, and the different technique of the ball screw is required according to the application field. Particularly, a ball screw applied to a vehicle includes a steering system, a brake system, a seat moving device, and a transmission system. The performance of the ball screw in these devices plays an important role in delivering fast and accurate power transmission. In addition, the own rigidity and the driving noise according to the performance of the ball screw may have a great influence on the ride comfort and the safety of the driver. However, since the first application of ball screws to the machinery industry, the case of R&D applied to the automotive parts industry is not so significant. So far, the research history on the influence on the overall driving performance of the ball screw with various conditions applied, based on a single factor of the ball screw has been pretty insufficient. Therefore, in this study, we aim to improve the performance by focusing on the performance of the ball screw by applying various conditions based on a single design factor in the circulation system. The selected single design factor is to apply the cycloid curve to a circulation area in the circulation part to obtain a cycloid curve which has the highest performance that a ball screw can have and with the smoothest ball flow. In addition, based on the results, we intend to reduce the failure cost that may be incurred in developing future ball screws for automobiles, and to establish a database that can be applied to the developed products by deriving the optimal shape. In this study, dynamic analysis of ball screw with an end cap circulation structure was performed. The dynamic analysis process seeks to understand the flow of the ball for a single end cap model designed according to design variables. It is expected that the performance of the whole ball screw system can be predicted by comparing with the end cap applied to the ball screw assembly based on the result of the dynamic analysis of the single end cap model later.

전기자동차 구동 모터용 중공 로터 샤프트에 관한 연구

손금열 경상대학교 융합과학기술대학원 2018 국내석사

The drive motor plays an important role in the performance of the electric vehicle and the rotor shaft also requires high quality and precision during manufacturing process. This study used the hollow shaft in the drive motor in order to lose its weight. By using structural analysis program ANSYS, the equivalent stress of the hollow shaft is evaluated and compared with the original shaft. Also, the shaft strength design was verified by comparing with strength theory of AGMA standard. Through this process, the weight could be reduced by about 40.5% compared to the original shaft. with SCM440H and SCM822H.

대형건설 중장비용 주행감속기의 성능을 위한 시험적 고찰

김성용 경상대학교 융합과학기술대학원 2018 국내석사

The driving gear system in heavy construction vehicles translates speed and torque. And it can converts the vehicle direction. Recently, many heavy construction vehicles require higher torque and longer durability. The driving gear system is generally evaluated by the ISO6336 standard, and the zero-failure time and the life time are calculated. And the driving gear system is disassembled in all internal components for inspection. This study showed that the driving gear system in heavy construction equipment satisfied the life time of 1,000 hr, and showed that the breakup time of the second spherical roller bearing had about 1.82 times of theoretical bearing life time.

중형 풍력발전기용 유성 기어시스템의 강도 및 경량화 해석 : 풍력 발전기 유성기어시스템을 중심으로

김동명 경상대학교 융합과학기술대학원 2016 국내석사

Wind turbines should maintain their long lifetime and reduce mechanical/electrical defaults or problems in order to produce continuous power with low cost. Many mechanical/electrical defaults or problems would happen in the power transmission or the pitch-drive system in the wind turbine. The pitch-drive system is operated by the pitch moment of the wing blade and return to the original position by spring back force. It is one of the effective power control method in the wind turbine. Therefore, many researchers have also applied finite element methods and experimental verifications in order to reduce their weight and to maintain their strength without defaults. In this study, the planetary gear system of the pitch-drive system in medium-sized wind turbine is verified for their strength by the structural analysis, and is obtained for their weight reduction by the shape optimization.

대형 가스터빈 차폐막의 소음 저감에 관한 연구

박성규 경상대학교 대학원 2016 국내석사

Dwelling sites are mostly formed around power plants newly founded today, increasing noise-related disputes and people living near the power plant are constantly exposed to a noise source and are mentally affected upon the construction of the power plant. Recently the noise-related reference value generated in power plants and construction sites near big cities is being strengthened but noise generated by the gas turbine, the main equipment of combined-cycle power plants is still the level that can cause pollution to the surrounding living environment and workspace. In order to solve this noise problem, enclosure is installed around the gas turbine when building a combined-cycle power plant and the performance of the enclosure is one of important factors in reducing building external noise. Therefore, this paper identified the transmission characteristics of the enclosure and the characteristics of external noise targeting the enclosure used in power plants and proposed measure for noise reduction. In order to predict the noise characteristics, we conducted the sound transmission loss analysis and compared the transmission characteristics according to the change in thickness and existing enclosure. We also installed a support and predicted the transmission characteristics by varying the shape and arrangement of the support. Next, based on the transmission loss research, external noise analysis was carried out and ray-acoustics was used. It is thought to be able to effectively present soundproof measures when designing a gas turbine by examining the noise reduction performance according to the design variables presented in this study.

협소 공간 절삭가공용 앵글 헤드 스핀들의구조 및 최적화 해석

성철훈 경상대학교 융합과학기술대학원 2019 국내석사

In order to improve the fuel economy and dynamic behavior of automobiles, the weight reduction tendency of automobile parts is obvious. Also, in order to maximize assembly and maintenance convenience, various parts are integrated and modularized. Multi-piece methods require many manufacturing processes and become a factor of lowering the strength of parts. It is advantageous to overcome the disadvantages by integrally manufacturing to reduce the processing steps and ensure the strength of the parts. However, when it is necessary to process in a narrow space inside the part, it is impossible to process with the existing spindle. This problem can be solved by using an angle head spindle. Since the angle head spindle can be machined side-by-side, it is very effective for improving the productivity and improving the machining quality by saving the machining time and simplifying the production process. Moreover, the competitiveness of the design technology of the automotive brake system can be secured because it can process without interfering with tools in a narrow space like the integral caliper housing. The angle head spindle is only a component of a machine tool, but it is a core part that requires high technology and is highly utilizable in products requiring high precision machining. Therefore, various and continuous studies needs for angle head spindles in areas such as vibration absorption, operational safety, excellent dimensional stability, and strength. In this paper, we propose an optimal design for angle head spindle by performing structural analysis and shape optimization for angle head spindle gear and case.

소형전기자동차용 감속기의 기어 설계에 관한 연구

이재구 경상대학교 대학원 2019 국내석사

Recently, the main industry topics of automobiles have been fuel economy and environmental regulation. In particular, European countries, especially Germany, have imposed restrictions on exhaust gas and the standards have been steadily strengthened. In these cases, electric vehicles are the best alternative to cars that currently use internal combustion engines. Electric vehicles are equipped with inverters, motors and gearbox instead of engines and transmissions. The gearbox is one of the important components for transmitting power from the electric motor to the wheel. therefore, the design of the gearbox is very important. The gearbox has only one gear ratio, so setting the appropriate gear ratio is very important. However, because there are no standards for design factor other than gear ratios, most engineers only design gears based on their experience. In particular, the gear module and the number of teeth are the main factors of the gear size and profile, but there is no standard. In order to solve this problem, it is necessary to understand the structural stability through the design factors of the gears. In this paper, we consider the module and the number of teeth as the main factors. Constraints are the fixed distance between the each axe of the shafts and final gear ratio. In this paper, the main factors are the gear modules and number of teeth. The constraint is the distance of each shaft and the final gear ratio. In order to predict the structural characteristics, we conducted a structural analysis and compared the maximum equivalent stress according to a change in the gear module and the number of teeth. Based on the structural analysis research, it is considered that structural stability can be effectively presented when designing a gear system.