• Title/Summary/Keyword: Angular contact ball bearing

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Rotordynamic Analysis of Automotive Turbochargers Supported on Ball Bearings and Squeeze Film Dampers in Series: Effect of Squeeze Film Damper Design Parameters and Rotor Imbalances (볼 베어링과 스퀴즈 필름 댐퍼로 지지되는 차량용 터보차저의 회전체동역학 해석: 스퀴즈 필름 댐퍼 설계 인자와 회전체 불균형 질량의 영향)

  • Kim, Kyuman;Ryu, Keun
    • Tribology and Lubricants
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    • v.34 no.1
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    • pp.9-15
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    • 2018
  • Modern high-performance automotive turbochargers (TCs) implement ceramic hybrid angular contact ball bearings in series with squeeze film dampers (SFDs) to enhance transient responses, thereby reducing the overall emission levels. The current study predicts the rotordynamic responses of the commercial automotive TCs (compressor wheel diameter = ~53 mm, turbine wheel diameter = ~43 mm, and shaft diameter at the bearing locations = ~7 mm) supported on ball bearings and SFDs for various design parameters of SFDs, including radial clearance, axial length, lubricant viscosity, and rotor imbalance conditions (i.e., amplitudes and phase angles) while increasing rotor speed up to 150 krpm. This study validates the predictive rotor finite element model against measurements of mass, polar and transverse moments of inertia, and free-free mode natural frequencies and mode shapes. A nonlinear rotordynamic model integrates nonlinear force coefficients of SFDs to calculate the transient responses of the TC rotor-bearing system. The predicted results show that SFD radial clearances, as well as phase angles of rotor imbalances, have the paramount effect on the dynamic responses of TC shaft motions.

연삭기용 유정압 주축의 복합배열에 관한 연구

  • 이찬홍;이후상
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1994.04b
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    • pp.458-461
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    • 1994
  • 최근에 상품의 국제경쟁력 강화를 위해서 생산공정 시간의 단축과전문 기능인력의 부족에 대응하는 중소로 트의 다품종 생산 합리화가 기계 제조업 전체에 확산되어 가고 있다. 본 연구에서는 연삭기용 유정압 주 축의 일반적인 형태인 전부, 후부 유정압 베어링의 장착구조 대신에 기존의 정, 동특성을 유지하면서 저가의 전부 유정압베어링과 후부 Angular Contact Ball Bearing의 복합배열 구조를 제시하고 이때의 정적, 동적 성능을 이론적으로 비교, 평가하였다.

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A Study on the Thermal Behavior of Bearing Surroundings using State-Space in Machine Tool Spindle System (공작기계 스핀들시스템에서 상태공간을 이용한 베어링 주변의 열거동에 대한 연구)

  • 신동수;정성종
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1995.10a
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    • pp.1045-1049
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    • 1995
  • This paper proposes the state-space model of the thermal behavior of the spindle system to establish dynamic mathematical model of thermal characteristics in machine tool spindle system. the model is derived form physical law of heat transfer and thermoelasticity and represents the thermal behavior induced by uneven thermal expansions whitin a bearing. The model, which is sucessfully validated for two typical configurations of high speed spindle assembles, provides a tool for understanding the basis mechanics of induced thermal expansion as a function of initial preload, spindle speed and housing cooling conditions.

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Study on Thermal Behavior of Motor Integrated Spindle With Air Cooling System (공기냉각 모터내장형 주축계의 열거동에 관한 연구)

  • Lee, D.W.;Park, D.B.;Park, H.K.
    • Journal of the Korean Society for Precision Engineering
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    • v.12 no.8
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    • pp.86-91
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    • 1995
  • Recently, motor integrated spindle is often used in a high speed spindle system of machine tools in order to increase machining speed. The important problem in high speed motor integrated spindle is to reduce thermal effect occured by motor and ball bearings. In this study, the effect of heat transfer from motor is investigated. The experimental equipment is composed with oil-air lubrication method, air cooling system and angular contact ball bearings. The results show that the thermal effect in motor is larger than in ball bearing until DmN 8000,000 with air cooling.

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Temperature increase of the spindle bearing system having a gear on the bearing span (베어링 스팬상에 기어구동축을 갖는 스핀들 베어링 시스템의 열특성에 관한 연구)

  • Choi, Jin-kyung;Lee, Dai-Gil
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.22 no.1
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    • pp.33-43
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    • 1998
  • High cutting speeds and feeds are essential requirements of a machine tool structure to accomplish its basic function which is to produce a workpiece of the required geometric form with an acceptable surface finish at as high a rate of production as is economically possible. Since the bearings in high speed spindle units are the main heat source of the total cutting system, in this work, the thermal characteristics of the spindle bearing system with a tilting axis were investigated using finite element methods to improve the performance of the spindle bearing system. Based on the theoretical results, a specially designed prototype spindle bearing system has been manufactured. Using the manufactured spindle bearing system, the thermal characteristics were measured. From the comparison of the experimental results with the theoretical ones, it was found that the finite element method predicted well the thermal characteristics of the spindle bearing system.

Thermal Analysis of a Motor-Separated Spindle System for High-Speed HMC (모터분리형 초고속 머시닝센터 주축계의 열특성 해석)

  • 김석일;권태균;나상준
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2001.10a
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    • pp.237-242
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    • 2001
  • This paper presents the thermal characteristics analysis of a high-speed HMC spindle system with angular contact ball bearings, built-in motor, oil-jet lubrication method, oil jacket cooling method, and so on. The spindle system is composed of the main spindle and sub-spindle which are mechanically connected by a flexible coupling. The spindles are supported by two front and rear bearings, and the built-in motor is located between the front and rear bearings of the sub-spindle. The thermal analysis model of spindle system is constructed by the finite element method, and the thermal characteristics in the design stage are estimated based on temperature distribution, heat flow and thermal deformation under the various testing conditions related to material of bearing ball, spindle speed and coolant temperature.

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Thermal Characteristics Analysis of a High-Speed HMC Spindle System (초고속 HMC 주축계의 열특성 해석)

  • 김석일;김기상;김기태;나승표
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2001.04a
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    • pp.441-446
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    • 2001
  • This paper presents the thermal characteristics analysis of a high-speed HMC spindle system with angular contact ball bearings, built-in motor, oil-jet lubrication method, oil jacket cooling method, and so on. The spindle system is composed of the main spindle and sub-spindle which are mechanically connected by a flexible coupling. The spindles are supported by two front and rear bearings, and the built-in motor is located between the front and rear bearings of the sub-spindle. The thermal analysis model of spindle system is constructed by the finite element method, and the thermal characteristics in the design stage are estimated based on temperature distribution and heat flow under the various testing conditions related to material of bearing ball, spindle speed and coolant temperature.

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Thermal Characteristics Analysis of a High-Speed Motor-Separated Spindle System Using Oil-Jet Lubrication Method (오일-제트 윤활 방식의 모터 분리형 초고속 주축계의 열 특성 해석)

  • 김석일;김기태
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.13 no.1
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    • pp.69-75
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    • 2004
  • This paper presents the thermal characteristics analysis of a high-speed motor-separated spindle system consisted of angular contact ball bearings and built-in motor with oil-jet lubrication. The spindle system is composed of the main spindle and sub-spindle which are mechanically connected by a flexible coupling. The spindles are supported by two front and rear bearings, and the built-in motor is located between the front and rear bearings of the sub-spindle. The thermal analysis model of spindle system is constructed by the finite element method, and the thermal characteristics in the design stage are estimated based on temperature distribution and heat flow under the various testing conditions related to material of bearing ball, spindle speed and coolant temperature.

An Analysis of Elastohydrodynamic Lubrication of Elliptical Contacts : Part II (타원접촉의 탄성유체윤활해석 : 제2보)

  • 박태조;현준수
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 1999.06a
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    • pp.182-188
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    • 1999
  • A theoretical study of elastohydrodynamic lubrication of elliptical contacts with both rolling and spin has been carried out. A finite difference method and the Newton-Raphson method are applied to solve the problem. The velocity vectors resulting from combined spin and rolling/sliding motion lead to asymmetric pressure distributions and film shapes. Film contours and variations of the minimum and central film thicknesses are compared with various spin-roll ratios. At high spin-roll ratios the minimum film thickness is considerably reduced, whereas the central film thickness decreases less dramatically, The present numerical scheme can be used in the analysis of general elliptical contact problems.

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An Elastohydrodynamic Lubrication of Elliptical Contacts : Part II - The Effect of Spin Motion (타원접촉의 탄성유체윤활 : 제2보 - 스핀운동의 영향)

  • Park, Tae-Jo
    • Tribology and Lubricants
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    • v.23 no.2
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    • pp.49-55
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    • 2007
  • A numerical analysis of elastohydrodynamic lubrication of elliptical contacts with both rolling and spinning has been carried out. A finite difference method with non-uniform grid systems and the Newton-Raphson method are applied to solve the problems. The velocity vectors resulting from combined spinning and rolling/sliding motion lead to asymmetric pressure distributions and film shapes. Pressure distributions, film contours and variations of the minimum and central film thicknesses are compared with various spin-roll ratios. Reduction of the minimum film thickness under spinning is remarkable whereas the central film thickness is relatively less. The spin motion have large effect on variations of the minimum film thickness with load parameter which are small in pure rolling/sliding cases. Therefore present numerical scheme can be used in the analysis of general elliptical contact EHL problems and further studies are required.