PMLSM의 디텐트력 및 Lateral Force 최소화를 위한 V-skew 모델에 관한 연구

黃寅喆(In-Cheol Hwang),張基鳳(Ki-Bong Jang),金奎卓(Gyu-Tak Kim) 대한전기학회 2008 전기학회논문지 Vol.57 No.3

Permanent Magnet Linear Synchronous Motor (PMLSM) has high efficiency, high energy density, and high control-ability. But, the detent force always is produced by the structure of slot-teeth. There are the disadvantages such as noise and vibration of the apparatuses are induced and the control ability is curtailed because detent force acts as thrust ripple. Therefore, the detent force reduction is an essential requirement in PMLSM. Generally, the method, skewing permanent magnet or slot-teeth, is used to reduce the detent force. But the thrust is decreased at the same time. If permanent magnet is skewed, the lateral force which operates as the perpendicular direction of skew direction is generated in linear guide of PMLSM. So, V-skew model is proposed for the reduction of lateral force. The lateral force acts as braking force in linear motion guide, and it has bad influence to the characteristics of PMLSM. However, these problems will not be solved by 2-dimensional Finite Element Analysis(FEA). So, in this paper 3-dimensional FEA is applied to analyze the PMLSM where permanent magnet is skewed and has overhang. The detent force and thrust characteristics considering skew and overhang effects of permanent magnet are analyzed by 3-dimensional FEA and the results are compared with experimental values to verify the propriety of analysis.

Low CBN 코팅공구의 SCM440 선삭시 절삭력변화에 관한 연구

방홍인(Hong-In Bang),김태영(Tea-Young Kim),오성훈(Sung-Hoon Oh) 한국기계가공학회 2013 한국기계가공학회지 Vol.12 No.1

In recent years, high hardness steel is used for most of the material in many areas including aircraft, nuclear power, space exploration and automotive parts. Low CBN tools are widely used in industrial field which can effectively process high hardness steel of HRC 45 or harder. The results of this study demonstrated, when high hardness steel, SCM440 is turned with Low CBN tools coated with TiN and TiAlN coatings respectively, that both the thrust force and cutting force tends to increase with more increase in cutting force than thrust force, as the feed rate increases at constant cutting speed. In addition, the size of the cutting force and thrust force does not change with the increased cutting speed at the same feed rate, but the tool life is reduced if the cutting speed is increased to shorten the machining time. Therefore, it is recommended to limit the cutting speed at 250 m/min maximum or less. Furthermore, comparing the cutting force of the three tools at the same cutting condition, Tin coating tool showed the smallest cutting force and Low CBN was the next, and the TiAlN coating tools showed the largest cutting force.

PMLSM의 SKew 와 Overhang 효과에 대한 3D 유한 요소 해석

李東燁(Dong-Yeup Lee),黃寅喆(In-Cheol Hwang),姜圭洪(Gyu-Hong Kang),金奎卓(Gyu-Tak Kim) 대한전기학회 2006 전기학회논문지 B Vol.55 No.10

This paper deals with skew and overhang effects of permanent magnet linear synchronous motor(PMLSM). The detent force and thrust characteristics considering skew and overhang effects of permanent magnet are analyzed by 3D finite element method and the results are compared to experimental values. As skew and overhang are applied to permanent magnet, the thrust is almost the same value but the detent force is reduced remarkably. By harmonic analysis, the distortion ratio of thrust is remarkably reduced from 4.29[%] to 2.3[%]. and. the ripple ratio of thrust is decreased from 8.2[%] to 3.56[%] at the same time. But, the lateral force which operate as the perpendicular direction of skew direction is generated. The lateral force and normal force acts by braking force between mover and LM-guide. Therefore. normal force and lateral force's reduction is required for more efficient drivinz of PMLSM.

충격파 시험장치를 이용한 추력 측정

진상욱(Sangwook Jin),황기영(Kiyoung Hwang),박동창(Dongchang Park),민성기(Seongki Min) 한국추진공학회 2017 한국추진공학회 학술대회논문집 Vol.2017 No.5

충격파 시험장치를 이용하여 추력을 측정하는 방법을 소개하였다. 충격파 시험장치를 이용하여 엔진의 추력을 측정하기 위해서는 일반적인 엔진시험 시설에서 추력을 측정하기 위해 사용하는 밸런스가 힘의 평형상태에 도달하지 못하기 때문에 응력파 힘 밸런스(Stress Wave Force Balance) 방법을 이용하여 측정한다. 본 논문에서는 모델 힘 밸런스(force balance)에 대해 충격하중을 주고 유한요소법(FEM)으로 변형률을 계산하였다. 충격하중과 변형률의 관계를 역합성곱(de-convolution)하여 천이함수를 도출하였다. This paper introduces the method how to measure the thrust in impulse facility. In a Facility having such a short duration time of steady flow, there’s no time to reach a steady state of the forces acting on model so that the test model vibrates until the end of the flow. The forces exerted on an engine exist with vibration so that the usual force balance can not be used. SWFB(Stress Wave Force Balance) technique is utilized in a shock tunnel to get the thrust. As an example, a model force balance has been calculated its strain against impulse force by using FEM(Finite Element Method). A transfer function between the impulse force and strain has been obtained by the way of de-convolution.

운전 상태에서의 터보차저 축 추력 예측

이인범(Inbeom Lee),홍성기(Seongki Hong),김영철(Youngchul Kim),최복록(Boklok Choi) 한국자동차공학회 2016 한국 자동차공학회논문집 Vol.24 No.6

This paper deals with an analytical and experimental investigation to predict the axial thrust load that results from turbocharger operating conditions. The Axial forces acting on the turbocharger thrust bearing are caused by the unbalance between turbine wheel gas forces and compressor wheel air forces. It has a great influence on the friction losses, which reduces the efficiency and performance of high-speed turbocharger. This paper presents the calculation procedure for the axial thrust forces under operating conditions in a turbocharger. The first step is to determine the relationship between thrust forces and strains by experimental and numerical methods. The analysis results were verified by measuring the strains on a thrust bearing with the specially designed test device. And then, the operating strains and temperatures were measured to inversely calculate the thrust strains which were compensated the thermal effects. Therefore it’s possible to calculate the magnitudes of the thrust forces under operating turbocharger by comparing the regenerated strains with the rig test results. It will possible to optimize the design of a thrust bearing for reducing the mechanical friction losses using the results.

An Analytic Study of Chiropractic High-Velocity Thrust

Naoki Uemura,Nozomi Uemura,Jin OK Choi 한서대학교 보완대체의학연구소 2011 Research Journal of Complementary and Alternative Vol.- No.2

A thrust in chiropractic is performed mainly by delivering a precise instantaneous thrust. The authors have constructed a model that demonstrates transmission of a directed force by contraction of muscle in the upper arm, using physical equations. Furthermore, we constructed a thrust force measuring apparatus and performed actual measurements. Measurement results have revealed that there was a high correlation between data obtained from the actual measurements and those from obtained from the model. Furthermore, the results suggested that the measuring apparatus can be a device that judges thrust and velocity in future studies.

A Method for Identifying Human-generated Forces during an Extensor Thrust

Seong-Wook Hong,Vlad Patrangenaru,William Singhose,Stephen Sprigle 한국정밀공학회 2006 International Journal of Precision Engineering and Vol.7 No.3

Some wheelchair users with neuromuscular disorders experience involuntary extensor thrusts, which may cause injuries via impact with the wheelchair, cause the user to slide out of the wheelchair seat, and damage the wheelchair. Knowledge of the human-generated forces during an extensor thrust is of great importance in devising safer more comfortable wheelchairs. This paper presents an efficient method for identifying human-generated forces during an extensor thrust. We used an inverse dynamic approach with a three-link human body model and a system for measuring human body motion. We developed an experimental system that determines the angular motion of each human body segment and the force at the footrest, which was used to overcome the mathematical indeterminacy of the problem. The proposed method was validated experimentally illustrating the force-identification process during an extensor thrust.

A Method for Identifying Human-generated Forces during an Extensor Thrust

Hong Seong-Wook,Patrangenaru Vlad,Singhose William,Sprigle Stephen Korean Society for Precision Engineering 2006 International Journal of Precision Engineering and Vol.7 No.3

Some wheelchair users with neuromuscular disorders experience involuntary extensor thrusts, which may cause injuries via impact with the wheelchair, cause the user to slide out of the wheelchair seat, and damage the wheelchair. Knowledge of the human-generated forces during an extensor thrust is of great importance in devising safer, more comfortable wheelchairs. This paper presents an efficient method for identifying human-generated forces during an extensor thrust. We used an inverse dynamic approach with a three-link human body model and a system for measuring human body motion. We developed an experimental system that determines the angular motion of each human body segment and the force at the footrest, which was used to overcome the mathematical indeterminacy of the problem. The proposed method was validated experimentally, illustrating the force-identification process during an extensor thrust.

터보차저의 축추력 예측을 위한 유한요소 모델 개발

이인범,최복록 한국기계기술학회 2016 한국기계기술학회지 Vol.18 No.3

The axial thrust acting on the turbocharger rotor is basically generated by the unbalance between turbine wheel gas forces and compressor wheel air forces. It has a significant influence on the friction losses, which reduces the overall efficiency and performance of high-speed turbocharger. Therefore, it’s important to calculate the thrust forces under operating conditions (surge, choke and etc.) in a turbocharger. The purpose of this paper is the development of numerical simulation methods which were verified by experimental results of axial thrust and thermally induced constraint tests of the turbocharger. The first FE model showed the relationship between thrust forces and strains by calculating the strains on specially designed thrust bearing and were compared with test results. And the second one is to identify the thermally induced strains in order to remove the thermal effects from measured strains. With these models, it’s possible to inversely predict the magnitudes of the axial thrust by directly measured strains and temperatures under operating turbocharger.

Levitation and Thrust Forces Analysis of Hybrid-Excited Linear Synchronous Motor for Magnetically Levitated Vehicle

Cho, Han-Wook,Kim, Chang-Hyun,Han, Hyung-Suk,Lee, Jong-Min The Korean Institute of Electrical Engineers 2012 Journal of Electrical Engineering & Technology Vol.7 No.4

This paper proposes a hybrid-excited linear synchronous motor (LSM) that has potential applications in a magnetically levitated vehicle. The levitation and thrust force characteristics of the LSM are investigated by means of three-dimensional (3-D) numerical electromagnetic FEM calculations and experimental verification. Compared to a conventional LSM with electromagnets, a hybrid-excited LSM can improve levitation force/weight ratios, and reduce the power consumption of the vehicle. Because the two-dimensional (2-D) FE analysis model describes only the center section of the physical device, it cannot express the complex behavior of leakage flux, which this study is able to predicts along with levitation and thrust force characteristics by 3-D FEM calculations. A static force tester for a hybrid-excited LSM has been manufactured and tested in order to verify these predictions. The experimental results confirm the validity of the 3-D FEM calculation scheme for the description of a hybrid-excited LSM.