공회전시 배기계 이음에 대한 수학적 계산 및 예측기법에 대한 연구

장진만(Jinman Jang),김기동(Kidong Kim),김준완(Junewan Kim),김증희(Joonghee Kim) 한국자동차공학회 2011 한국자동차공학회 학술대회 및 전시회 Vol.2011 No.11

In general, the main source of vehicle noise is the ignition of engine and to diminish the degree of the noise, exhaust system is used as complicated filters for attenuating the noise more or less. But, even these kinds of filters are playing their roles at their expected frequencies bands, some noises still can be detected by passengers. They are so called ‘abnormal noises’ ,which are discovered when their anti-filters are working well, and it is very difficult to find what is the real problem and what is the basis of this phenomenon. Usually, frequency analysis is the most useful method for studying noise phenomena, but main effect of abnormal noise comes from listener’s feeling, therefore only frequency analysis process is not enough to clarify not only the cause but also the phenomenon itself. In this study, one of the abnormal noise, which can be detected very easily at the tail pipe, has been examined by mathematical way to define the cause of feeling of abnormal noise more effectively and precisely, furthermore also noise filter development process has been developed as a result in order to design proper filter system for exhaust system. For the validation of this calculation and design process, virtual noise has been exerted to calculated filters which had been designed properly by the calculation of former step and then, the noise has been accessed as a listener’s feeling by sound feeling matrices of octave band modulation.

차량 하체 이상 소음에 대한 연구

한재희(Jaehee Han),김상진(Sangjin Kim),한성제(Sungje Han) 한국자동차공학회 2017 한국자동차공학회 학술대회 및 전시회 Vol.2017 No.11

The purpose of this thesis is to identify the main cause of abnormal noise in order to eliminate noise from on the vehicle"s under body, and to analyze and propose solution. Today consumers’ expectations for the domestic automotive industry have risen sharply and the quality of the automobile has a major factor affecting customers. The abnormal noise from the under body is affecting the customer’s complaint index. This study attempted to establish the cause of abnormal noise happened from the inside of the shock absorber. The red-x tool that has statistical technique was used. The Red-X tool has a more specific and objective method, making it possible to present a clear root cause of the noise. Component analysis methods were used to identify the occurrence of noise, and further experiments were conducted, such as selecting control factors and sensitivity analysis to eliminate fundamental noise. Based on the sensitivity analysis results, the optimal process conditions were configured, and finally, the components that is produce used this process conditions was confirmed making it has good performance and was removed the noise.

후륜 캘리퍼의 딱 이음 개선을 위한 연구

김상범(Sangbum Kim),윤준희(Joonhee Yun),김태욱(Tae uk Kim),양훈홍(Soonhong Yang),마재현(Jaehyeon Ma) 한국자동차공학회 2024 한국자동차공학회 학술대회 및 전시회 Vol.2024 No.11

This paper describes a study of improvement of abnormal noise of rear brake caliper. The demand for electric vehicles is increasing worldwide, and as the transition from existing internal combustion engines to electric vehicles increases, the weight of batteries increases, resulting in an increase in the overall weight of the vehicle. Accordingly, the torque applied to the front and rear calipers during braking is increasing. For this reason, the frequency of abnormal noise (sounds like ‘ddack’) occurring during initial braking in electric vehicles is increasing, and several improvement plans were evaluated to reduce or remove this noise.<BR/> First of all, an analysis of the mechanism by which noise occurs during initial braking was conducted. ODS (Operating Deflection Shapes) analysis was performed by installing vibration sensors on the pad, torque member, and caliper body. Then, the 7 samples were made and evaluated to improve the noise.<BR/> As a result of the evaluation, as the pad liner's supporting force in the disk rotation direction increased, the amount of pad vibration decreased, thereby reducing the noise. Increased friction between the piston and pad shim has the effect of improving noise, but the effect was insignificant compared to the increase in pad liner’s supporting force.<BR/> Additionally, the conditions under which the noise is likely to occur are that the frequency increases as the temperature is low and the humidity is high. Also, the frequency increased when the gap between the torque member and the pad exceeded a certain level.

차륜형 전투차량의 충격흡수기 이상소음 발생에 관한 연구

김록한,강승주,오은빈,이지완 한국기계기술학회 2023 한국기계기술학회지 Vol.25 No.5

In this study, the abnormal noise phenomenon generated intermittently in the shock absorber of the combat armored vehicle was approached from the side of the squeak joint to solve the phenomenon. In order to identify the cause of the noise, the factors causing friction in the shock absorber were checked from the viewpoint of problem product analysis, process, and design. As an improvement plan, by improving the non-lubricated section in the nitrogen chamber, the operating noise was reduced to a level lower than that of a general automobile engine along with the elimination of noise. Considering that this is a combat vehicle, it is judged that it has been improved so as not to affect the survivability and health of the crew during equipment operation. Through the improvement of this study, it is expected to prevent power loss and improve the emotional quality of our soldier.

An Experimental Study for Improvement of EOP Abnormal Vibration on Automatic Transmission

오종민(Jongmin Oh) Korean Society for Precision Engineering 2023 한국정밀공학회지 Vol.40 No.3

As electrification trends for the automotive industry have accelerated and the demand for high efficiency has increased, hybrid transmissions have been pushed to enlarge the operating range of EOP. And in conventional transmissions, an Idle Stop and Go (ISG) EOP is becoming imperative. The operating conditions of the ISG EOP make it difficult to gain advantages by masking the effects of engine firing or drive noise. Thus, it is necessary to study noise in operating ISG EOPs. Also, the EOP inner components require precise processing and manufacturing because they should be made to a compact size owing to vehicle layout limitations. This paper first describes the results of an experimental study on the abnormal vibration phenomenon, which makes EOP operating noise worse. And secondly it was investigated the cause of abnormal vibration phenomenon which occurs due to processing and manufacturing problems in the process of developing the operating noise of the EOP for ISG on FF type automatic transmission. Finally, the verification results after improvement were described.

캐비닛 구조물의 내부 마찰소음 발생 메커니즘에 관한 실험적 연구

이동규(Dong Gyu Lee),박정현(Jung-Hyun Park),박기홍(Ki Hong Park),하병국(Byung-Kuk Ha),김형식(Hyeong-Sik Kim),박상후(Sang Hu Park) 대한기계학회 2013 大韓機械學會論文集A Vol.37 No.2

대형 냉장고의 경우 내부구조가 복잡하고 냉장고 문을 열고 닫을 때 냉장고 내부에 온도편차가 발생하며, 또한 진동에 의한 흔들림이 발생하게 된다. 이러한 다양한 원인에 의하여 간헐적으로 부품간 마찰에 의한 이상소음이 발생하기도 한다. 따라서 본 연구에서는 이러한 이상소음의 원인과 메커니즘을 실험적으로 분석하고 이것을 줄일 수 있는 가능성에 대하여 제안하고자 한다. 이상 소음을 구현하기 위한 실험장치를 구성하고 냉장고 문의 열림과 닫힘에서 발생되는 변형량 분석과 온도 변화에 따른 내부 압력변화를 측정하여 소음발생의 주요원인에 대하여 분석하였다. 또한 설계초기 단계에서 적용이 가능한 소음저감 방법론을 제안하였다. A large-sized refrigerator has a complicated inner structure such as a shelf and a rack for product loading. Therefore, when the refrigerator door is opened and closed, the temperature inside the refrigerator varies and vibrations occur due to the physical force applied for opening and closing the door. Owing to these factors, an abnormal sound is generated by the relative distortion between the inner structures. In this study, we aimed to clarify the mechanism that generates this abnormal noise inside the refrigerator using experimental approaches, and we also investigated ways by which to reduce this noise. Toward this end, we developed an experimental setup for measuring the noise, temperature, inner pressure, as well as amount of vibration, and we analyzed the main factors causing the noise based on the experimental results. Furthermore, we suggested a way by which to reduce the noise; this method can be applied in the design stage itself.

DEVELOPMENT OF THE WEAR RESISTANT BALL NUT ASSEMBLY IN THE RACK-BASED ELECTRIC POWER STEERING

Soo Sik Chung,Young-Ze Lee,Eun Seok Kim 한국자동차공학회 2020 International journal of automotive technology Vol.21 No.3

Electric Power Steering (EPS) is rapidly evolving in terms of performance. However, the abnormal noise from steering, which is experienced by the drivers, reduces the perfection of performance. In this study, the deterioration of Rackbased Electric Power Steering (R-EPS) samples by mileage was analyzed to investigate the cause of steering abnormal noise in the R-EPS applied to a large-sized luxury vehicle that is more sensitive to noise. The results from our analysis showed that the ball nut and screw in the ball nut assembly of R-EPS were in the mode of normal wear. However, the steel ball between the ball nut and screw showed irregular wear mode. It was found that the ball Φ5 has a larger contact area than the ball Φ4, which is advantageous for abrasion and irregular wear because stress is dispersed in the load. Moreover, the ball with Φ5 was superior to the ball with Φ4 in the results of abrasive and adhesive wear tests verified by the ball-on-disk test. Therefore, in the future R-EPS development, the ball with Φ5 compare to the ball with Φ4 should be proposed for the ball nut assembly. This is in order to eliminate the potential cause of steering abnormal noise.

기계전자 부품재료의 스틱슬립 특성 평가방법에 관한 연구

김두섭,김원진 한국음향학회 2024 韓國音響學會誌 Vol.43 No.3

본 연구에서는 기계전자 제품에 사용되는 소재의 마찰실험을 통해 스틱슬립 특성을 분석하고 냉장고 내부에서 발생하는 이상소음을 저감하는 개선안을 제안하였다. 소재의 스틱슬립 현상을 분석하기 위해 마찰실험장치를 제작하고 마찰실험을 수행하였다. 또한 냉장고 내부에서 발생하는 이상소음의 현상과 위치를 분석하기 위해 내부부품의진동과 소음 레벨을 측정하였다. 그리고 냉장고 현상분석 결과와 마찰실험 결과를 비교하여 냉장고 내부에서 발생하는 이상소음은 내부부품의 스틱슬립 현상에 의한 것임을 확인하였다. 마지막으로 이상소음을 저감하는 개선안을 제안하기 위해 다구찌 기법을 이용한 마찰실험을 수행하였다. 그리고 개선안을 냉장고에 적용하여 성능을 검증하였다. In this study, we analyzed the stick slip characteristics through friction experiments on materials used in mechanical and electronic products, and propose improvements to reduce abnormal noise generated inside refrigerators. To analyze the stick slip phenomenon of the materials, we fabricated a friction testing device and conducted friction experiments. Additionally, we measured the vibration and noise levels of internal components to analyze the occurrence and location of abnormal noise inside the refrigerator. By comparing the results of the refrigerator’s phenomenon analysis and friction experiment, we confirm that the abnormal noise occurring inside the refrigerator is caused by the stick slip phenomenon of internal components. Finally, to propose improvements for abnormal noise reduction, we performed friction experiments using the Taguchi method and validated the performance of the proposed improvements by applying them to refrigerators.

영구자석 진동에 기인한 HEV용 구동모터 이상 전자기 소음의 실험적 규명

김명규(Myunggyu Kim),하재원(Jaewon Ha),김대운(Daewoon Kim),김삼균(SamKyun Kim),김연호(Yeonho Kim) 한국자동차공학회 2011 한국자동차공학회 학술대회 및 전시회 Vol.2011 No.11

This paper investigates the abnormal electromagnetic noise of HEV traction motor due to Vibration of Permanent Magnet. In the paper, we introduce the mechanical and electromagnetical cause of magnetic unbalance of the HEV tranction motor and analyze the frequency of abnormal electromagnetic noise due to magnetic unbalance. We determine the abnormal electromagnetic noise is caused by the vibration of permanent magnet. And we develop the novel magnet insert method of HEV traction motor and improve the abnormal electromagnetic noise of HEV traction motor.

하이브리드 자동차 구동모터 비정상 소음 개선

김현수(Hyunsu Kim),김명규(Myunggyu Kim) 대한기계학회 2017 대한기계학회 춘추학술대회 Vol.2017 No.11

Electrical motor noise in hybrid electric vehicle (HEV) is in general expected that it has lower level in noise and vibration than conventional internal combustion engine does. In this paper, abnormal noise component, which may be annoying noise, of the traction motor occurred after an endurance vehicle test is investigated experimentally. The ±1 order of the number of slots is understood by a theoretical model, and the source of the abnormal noise is examined by cross-check investigation and is identified that it is caused by a failure of magnet fixing method. The improvement of the abnormal noise is confirmed by changing the fixing method from bond to mold.