• Title/Summary/Keyword: Metal Bearing

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Manufacturing of Micro Gas Bearing by Fe-Ni Nanopowder and Metal Mold Using LIGA (LIGA 금형몰드를 이용한 Fe-Ni계 나노분말의 초미세 가스베어링 제조)

  • Son, Soo-Jung;Cho, Young-Sang;Kim, Dae-Jung;Kim, Jong-Hyun;Chang, Suk-Sang;Choi, Chul-Jin
    • Journal of Powder Materials
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    • v.19 no.2
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    • pp.140-145
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    • 2012
  • This paper describes the manufacturing process of tilting pad gas bearing with a diameter of 5 mm and a length of 0.5-1 mm for power MEMS (Micro Electomechanical Systems) applications. The bearing compacts with nanopowder feedstock were prepared by Ni-metal mold with 2-mold system using LIGA process. The effect of the manufacturing conditions on sintering properties of nanopowder gas bearing was investigated. In this work, Fe-45 wt%Ni nanopowder with an average diameter of 30-50 nm size was used as starting material. After mixing the nanopowder and the wax-based binders, the amount of powder was controlled to obtain the certain mixing ratio. The nanopowder bearing compacts were sintered with 1-2 hr holding time under hydrogen atmospheres and under temperatures of $600^{\circ}C$ to $1,000^{\circ}C$. Finally, the critical batch of mixed powder system was found to be 70% particle fraction in total volume. The maximum density of the sintered bearing specimen was about 94% of theoretical density.

HVOF spray coating of WC-metal powder for the improvement of friction, wear and corrosion resistance of magnetic bearing shaft material of turbo blower (터보불로워 용 회전체 주축 소재의 마찰, 마모 및 부식 저항 향상을 위한 WC-metal 분말의 초고속화염용사코팅)

  • Joo, Y.K.;Yoon, J.H.;Cho, T.Y.;Chun, H.G.
    • Corrosion Science and Technology
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    • v.12 no.1
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    • pp.7-11
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    • 2013
  • High velocity oxy-fuel (HVOF) spray coating of WC-metal powder (powder) was carried out to improve the resistances of friction, wear and corrosion of magnetic bearing shaft material Inconel718 (In718) of turbo blower. A micron sized WC-metal powder (86.5% WC, 9.5% Co 4% Cr) was coated onto In718 surface using HVOF thermal spraying. During the spraying, the binder metals and alloy such as Co, Cr and Co-Cr alloy were molten and a small portion of WC particles were partially decomposed to $W_2C$ and free carbon at above its decomposition temperature of $1250^{\circ}C$. The free carbon and excessively sprayed oxygen formed carbon oxide gases, resulting a porous coating of porosity of $2.2{\pm}0.3%$. The surface hardness of substrate increased approximately three times from 400 Hv of In718 to $1260{\pm}30Hv$ of the coating The friction coefficients of the coating were approximately $0.33{\pm}0.03$ at $25^{\circ}C$ and $0.26{\pm}0.03$ at $450^{\circ}C$. These values were smaller than those of In718 substrate at both temperatures due to the lubrication from the free carbon and the cobalt oxide debris. The corrosion resistance of the coating was higher than that of In718 both in salt water of 3.5% NaCl and acid of 1 M HCl solutions, on the contrary, it was lower in base solution of 1 M NaOH. According to this study, the HVOF WC-metal powder coating is recommended for the durability improvement of magnetic bearing shaft of turbo blower.

A Study on the Deformation Characteristics of a Slipper Bearing for High Pressure Piston Pump (고압 피스톤 펌프용 슬리퍼 베어링의 변형 특성에 관한 연구)

  • Koh, Sung-Wi;Kim, Byung-Tak
    • Journal of Ocean Engineering and Technology
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    • v.23 no.5
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    • pp.39-44
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    • 2009
  • The hydrostatic slipper bearing is generally used in high pressure axial piston pumps to support the load generated from two surfaces which are sliding relatively at low speed. The object of the bearing is to remove the possibility of direct contact by maintenance of an adequate oil film thickness between two metal surfaces. Because the bearing performance is influenced by the bearing deformation, it is highly dependent on the injection pressure, the bearing surface profile and so on. In this study, the deformation characteristics of a hydrostatic slipper bearing is investigated according to the injection pressure by the finite element analysis. In the analysis, the special boundary condition to take the fluid-structure interaction (FSI) into account is used on the interactive surface. The results, such as bearing deformation, stress and lifting force, obtained from the fully coupled analysis are compared with those from the single step sequential method.

Manufacturing System of Centrifugal Cast Metal Bearing by Dehydrogenation (탈수소 열처리 공정에 의한 원심주조 메탈베어링의 제조 시스템)

  • Kim, Jeung-Hun;Kim, Chung-Gu;Byen, Jea-Young;Lee, Eun-Suk;Yang, Ji-Yung;Choi, Won-Sik
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.19 no.5
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    • pp.111-117
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    • 2020
  • Centrifugal casting is suitable for producing hollow-products using centrifugal force. Bush type metal bearings are the key parts that facilitate the rotational movement of various machinery. Metal bearings produced by conventional centrifugal casting machines show rotational imbalance. Therefore, after injecting a large amount of material, the product's precision is secured in the secondary processing. Rotational imbalance is caused by the force acting on the rotary disc plate. In order to minimize rotational imbalance, NASTRAN was used for the optimal design and structural analysis. It was concluded that the rotating plate of the conventional centrifugal casting machine should be prevented from tilting. For this purpose, the location & thickness of the stiffeners were obtained through the optimum design. In the conventional centrifugal casting machine, both ends of the product are lower in temperature than the center part, so internal stress occurs. This solves this problem by inserting a heating coil into the rotating plate.

Study on the Durability of Composite Tilting Pad Journal Bearing for Turbo Compressor System under Oil-cut Situation (터보 컴프레셔용 복합재료 틸팅 패드 저널 베어링의 오일 공급 중단 상황에서의 내구성 연구)

  • Choe, Kang-Yeong;Jung, Min-Hye;You, Jun-Il;Song, Seung-A;Kim, Seong-Su
    • Composites Research
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    • v.29 no.3
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    • pp.111-116
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    • 2016
  • The tilting pad journal bearing for the turbo compressor application has a role to support high speed and heavy loading rotor. White metal has been widely used for the bearing material but the conventional bearing is immediately suspended and induces serious serious damage to the rotor under the unexpected oil cut situation or the insufficient oil film formation. The carbon fiber reinforced composite having high specific stiffness, specific strength and excellent tribological characteristics can solve these seizure problems. In this work, the study on the durability of high thermal resistance carbon fiber/epoxy composite tilting pad journal bearing under oil cut situation was conducted. The material properties of the composite materials including tensile, compressive and interlaminar properties were measured at room and high temperature of oil cut situation. To investigate the possibility of failure of composite tilting pad journal bearing under oil cut situation, the stress distribution of the composite bearing was analyzed via finite element analysis and the Tsai-Wu Failure index was calculated. To verify the failure analysis results, the oil cut tests for the composite tilting pad journal bearing were conducted using industrial test bench.

Fluid Dynamic Bearing Spindle Motors for DLP (DLP용 유체동압베어링 스핀들모터)

  • Kim, Yeung-Cheol;Seong, Se-Jin
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.60 no.2
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    • pp.82-90
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    • 2011
  • The small precision spindle motors in the high value-added products including the visible home appliances such as DLP projector require not only the energy conversion devices but also high efficiency, low vibration and sound operation. However, the spindle motors using the conventional ball bearing and sintered porous metal bearing have following problems, respectively: the vibration by the irregularity of balls and the short motor life cycle by the ball's abrasion and higher sound noises by dry contact between shaft and sleeve. In this paper, it is proposed that the spindle motor with a fluid dynamic bearing is suitable for the motor to drive the color wheel of the DLP(digital lightening processor) in the visible home appliances. The proposed spindle motor is composed of the fluid dynamic bearing with both the radial force and the thrust force. The fluid dynamic bearing is solved by the finite element analysis of the mechanical field with the Reynolds equations. The magnetic part of spindle motor, which is a type of Brushless DC Motor, is designed by the electro-magnetic field analysis coupled with the Maxwell equation. And the load capacity and the friction loss of fluid dynamic bearing are analyzed to bearing clearance variation by the fabrication error in designed motor. The design of the proposed motor is implemented by the load torque caused by the eccentricity and the unbalance of the fluid dynamic bearing when the motors are fabricated in error. The prototype of the motor with the fluid dynamic bearing is manufactured, and experiment results show the vibration, sound, and phase current at no load and color wheel load of the motors in comparison. The high performance characteristics with the low vibration, the low acoustic noise and the optimal mechanical structure are verified by the experimental results.

Digital Controller Design of a Magnetic Bearing System for High Speed Milling Spindle (고속 밀링 주축용 자기베어링 시스템의 디지털 제어기 설계)

  • 노승국;경진호;박종권
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2004.04a
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    • pp.398-403
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    • 2004
  • The demand of high speed machining is increasing because the high speed cutting providers high efficiency of process, short process time, improved metal removal capacity and better surface finish. Active magnetic bearings allow much high surface speed than conventional ball bearings and therefore greatly suitable for high speed cutting. The automatic control concept of magnetic bearing system provides ability of intelligent control of spindle system to increase accuracy and flexibility by means of adaptive vibration control. This paper describes a design and development of a milling spindle system which includes built-in motor with power 5.5㎾ and maximum speed 70,000rpm, HSK-32C tool holer and active magnetic bearing system. Magnetic actuators are designed for satisfying static load condition. The Performances of manufactured spindle system was examined for its static and dynamic stiffness, load capacity, and rotational accuracy. This spindle was run up to 70,000 rpm stably, which is 3.5 million DmN.

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A Study on the Shape Design and Nonlinear Analysis of Elastomeric Spherical Bearings for Railway Bridge Systems (철도교용 반구면 탄성체 베어링의 형상설계 및 해석에 관한 연구)

  • Oh, Ju;Cho, Hyun-Jin;Lee, Wan-Ha;Park, Jin-Young;Park, Kun-Nock
    • Proceedings of the KSR Conference
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    • 2009.05a
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    • pp.589-592
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    • 2009
  • In this paper is presenting the shape design and elastomer bearings, which functioned as a joint connecting sub-structures and upper-structures with a railway bridge bearing systems. The elastomeric spherical bearing shaped and composed of alternated 17-layered metal shim plates and 18-layered elastomer plates, respectively. The elastomeric spherical bearing a high compressive load for perpendicular axis to layered plates and flexible motions are provided coincidently for other axes. The three types of elastomers, which were developed due to a designed shear modules were applied. Nonlinear analysis based on the material properties of designed bearing were accomplished. Therefore, the Nonlinear Analysis results were compared with the calculation results and the optimized shapes were designed.

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Development of the Hybrid Composite Journal Bearing (하이브리드 복합재료 저널 베어링의 개발)

  • Kim Seong Su;Park Dong Chang;Lee Dai Gil
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2004.04a
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    • pp.63-66
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    • 2004
  • In this study, a hybrid composite journal bearing composed of carbon fiber reinforced phenolic composite liner and metal backing was manufactured to solve the seizure problem of metallic journal bearing materials because the carbon fiber has self-lubricating ability and the phenolic resin has thermal resistance characteristics. To estimate the wear resistance of carbon fiber phenolic composite, wear tests were performed at several pressures and velocities. The oil absorption characteristics, coefficient of thermal expansion, strength and stiffness of the composite were also tested. Using the measured stiffness values, the thermal residual stresses in the composite were calculated to check the reliability of the composite journal bearing.

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Design of an Elastomeric Bearing for a Helicopter Rotor Hub by Non-linear Finite Element Method (비선형 유한요소법을 이용한 헬리콥터 로터허브용 탄성체베어링 설계)

  • Kim, Hyun-Duk;Yoo, Si-Yoong;Park, Jung-Sun
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.38 no.6
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    • pp.612-619
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    • 2010
  • In this paper, an elastomeric bearing for a helicopter rotor hub is designed using nonlinear finite element method. The elastomeric bearing is the main component of the helicopter rotor hub that acts as a hinge to three motions(flapping, lagging and pitching) of rotor blade. The elastomeric bearing consists of rubber and metal plates. The stiffness design of the elastomeric bearing is important because elastic deformation of rubber is served to hinge. Accordingly, the elastomeric bearing is designed to satisfy the stiffness requirements for rotor hub bearing. In this study, a FE model generation algorithm is developed and stiffness characteristic of a rubber plate is analyzed for an efficient design of the spherical elastomeric bearing. It is proven that the elastomeric bearing satisfies stiffness requirements of the spherical bearing for a helicopter rotor hub.