• Title, Summary, Keyword: Journal Bearings

Search Result 1,103, Processing Time 0.047 seconds

A Design Fitness Analysis of Journal Bearings for LPLi Fuel Pump Application (LPLi 연료펌프 적용을 위한 저어널 베어링의 설계 적합성 해석)

  • Lee, An-Sung;Kim, Chang-Up
    • Tribology and Lubricants
    • /
    • v.25 no.5
    • /
    • pp.324-329
    • /
    • 2009
  • In this study a complex design fitness analysis of journal bearings is carried out for the LPLi rotary-vane fuel pump application, as an external and horizontal installation, in LPG vehicles. Bearings considered in the analyses are plain and 3-axial groove journal bearings. Upon reflecting the fact that the primary failure mode of bearings in the application is a premature friction and wear failure of bearing metal due to a very low viscosity of liquid fuel LPG as a bearing lubricant, the performance factors of bearings used in an evaluation process of design fitness are a load carrying capacity and vibration suppression ability relative to a rated speed. At this time the design variables of bearings are a radial clearance and length. Results show that, in terms of both of the load carrying capacity and vibration suppression ability, the plain journal bearings are superior to the 3-axial groove journal bearings and among the plain bearings the smaller the bearing clearance (5>10>$15\;{\mu}m$) is and the longer the bearing length (6<8<10<12<14 mm) is, the better the bearing performance is.

Maintenance Frequency Optimization of the Steam Turbine Journal Bearings by Condition-based Maintenance (상태기반정비에 의한 증기터빈 저널베어링의 정비주기 최적화)

  • Lee, Hyuk Soon;Chung, Hyuk Jin;Song, Woo Sok
    • Transactions of the Korean Society of Pressure Vessels and Piping
    • /
    • v.7 no.2
    • /
    • pp.7-13
    • /
    • 2011
  • Turbine journal bearings are designed to support the weight of the rotors on a hydrodynamic oil film and to provide dynamic stability to the rotor system. The life time of journal bearings is infinite theoretically because the journal bearings are separated from the shaft journal by oil film. But poor design, assembly, operation and maintenance can cause problems to the journal bearings. The FMEA(Failure Mode and Effects Analysis) results of the journal bearings show that frequent maintenance of the journal bearings can cause failures and reduction of the bearing life. Therefore, the maintenance periods and history of the journal bearings with the bearing FMEA results are reviewed in order to establish the optimized maintenance period of the journal bearing for the nuclear power plants. Consequently it is necessary to maintain a best condition of lubrication system, reject time-based maintenance and perform the condition-based maintenance of journal bearings in order to maintain optimum condition of the journal bearing.

The compression-shear properties of small-size seismic isolation rubber bearings for bridges

  • Wu, Yi-feng;Wang, Hao;Sha, Ben;Zhang, Rui-jun;Li, Ai-qun
    • Structural Monitoring and Maintenance
    • /
    • v.5 no.1
    • /
    • pp.39-50
    • /
    • 2018
  • Taking three types of bridge bearings with diameter being 100 mm as examples, the theoretical analysis, the experimental research as well as the numerical simulation of these bearings is conducted. Since the normal compression and shear machines cannot be applied to the small-size bearings, an improved equipment to test the properties of these bearings is proposed and fabricated. Besides, the simulation of the bearings is conducted based on the explicit finite element software ANSYS/LS-DYNA, and some parameters of the bearings are modified in the finite element model to reduce the computation cost effectively. Results show that all the research methods are capable of revealing the fundamental properties of the small-size bearings, and a combined use of these methods can better catch both the integral properties and the inner detailed mechanical behaviors of the bearings.

Behavior of Bridge Bearings for Railway Bridges under Running Vehicle

  • Choi, Eun-Soo;Yu, Wan-Dong;Kim, Jin-Ho;Park, Sun-Hee
    • International Journal of Railway
    • /
    • v.5 no.1
    • /
    • pp.10-21
    • /
    • 2012
  • Open steel plate girder (OPSG) bridges are the most prevalent railroad bridge type in Korea, constituting about 40% of all railroad bridges. Solid steel bearings, known as line type bearings, are placed in most OSPG railway bridges. However, the line type rigid bearings generate several problems with the bridge's dynamic behavior and maintenance in service. To compare and investigate the dynamic behaviors of line type, spherical and disk bearings, the vertical displacements of each bearing, including fixed and expansion type, under running vehicles are measured and analyzed. The displacements of disk and spherical bearings are measured after replacing the line type bearings with spherical and disk bearings. This study also analyzed dynamic behaviors of bridges. Furthermore, the deformation of the PTFE (Polytetrafluoroethylene) plate that is placed inside of expansion type spherical and disk bearings is measured and its effect on the dynamic behavior of the bridges is discussed. The up-lift phenomenon at the bearings installed for the steel bridges is estimated. The vertical displacements at mid-span of the bridges are compared according to the bearing types. Finally, the 1st mode natural frequencies are estimated, and the relationship to the vertical displacement is discussed.

Analytical Study on Effects of Bearing Geometry on Performance of Sliding Thrust Bearings (미끄럼 스러스트베어링의 성능에 미치는 베어링 형상의 영향 해석)

  • Kim, Ho-Jong;Choi, Sung-Pil;Ha, Hyun-Cheon
    • The KSFM Journal of Fluid Machinery
    • /
    • v.9 no.5
    • /
    • pp.7-13
    • /
    • 2006
  • In the present study, we develop an analysis module to be applicable to design of sliding thrust bearings. The pressure equation is solved by using the finite element method. Average lubricant temperature is obtained from using the energy balance method. The module developed has been applied to three types of thrust bearing, such as tapered-land thrust bearings of angular and diamond types, and tilting-pad thrust bearings. Effects of the dam of the tapered-lad thrust bearings have also been investigated. It has been seen that the tapered-land thrust bearings of angular type result in the highest load capacity, while the tilting pad thrust bearings result in the lowest lubricant temperature. It has also been seen that the dam in the tapered-land thrust bearings increases both the load capacity and lubricant temperature.

Seismic behavior of structures isolated with a hybrid system of rubber bearings

  • Chen, Bo-Jen;Tsai, C.S.;Chung, L.L.;Chiang, Tsu-Cheng
    • Structural Engineering and Mechanics
    • /
    • v.22 no.6
    • /
    • pp.761-783
    • /
    • 2006
  • The enlargement of interest in base isolators as an earthquake-proof design strategy has dramatically accelerated experimental studies of elastomeric bearings worldwide. In this paper, a new base isolator concept that is a hybrid system of rubber bearings is proposed. Uniaxial, biaxial, and triaxial shaking table tests are also performed to study the seismic behavior of a 0.4-scale three-story isolated steel structure in the National Center for Research on Earthquake Engineering in Taiwan. Experimental results demonstrate that structures with a hybrid system of rubber bearings composed of stirruped rubber bearings and laminated rubber bearings can actually decrease the seismic responses of the superstructure. It has been proved through the shaking table tests that the proposed hybrid system of rubber bearings is a very promising tool to enhance the seismic resistance of structures. Moreover, it is demonstrated that the proposed analytical model in this paper can predict the mechanical behavior of the hybrid system of rubber bearings and seismic responses of the base-isolated structures.

Analysis of Fluid Flow Characteristics Around Rolling Element in Ball Bearings (볼 베어링의 구름 요소 주위 유동 특성에 대한 해석)

  • Jo, Jun Hyeon;Kim, Choong Hyun
    • Tribology and Lubricants
    • /
    • v.28 no.6
    • /
    • pp.278-282
    • /
    • 2012
  • Various bearings such as deep-groove ball bearings, angular-contact ball bearings, and roller bearings are used to support the load and to lubricate between the shaft and the housing. The bearings of potential rolling systems in a turbo pump are the deep-groove ball bearings as comparing with the bearings with rolling elements such as cylindrical rollers, tapered cylindrical rollers, and needle rollers. The deep-groove ball bearings consist of rolling elements, an inner raceway, an outer raceway and a retainer that maintain separation and help to lubricate the rolling element that is rotating in the raceways. In the case of water-lubricated ball bearings, however, fluid friction between the ball and raceways is affected by the entry direction of flow, rotation speed, and flow rate. In addition, this friction is the key factor affecting the bearing life cycles and reliability. In this paper, the characteristics of flow conditions corresponding to a deep-groove ball bearing are investigated numerically, with particular focus on the friction distribution on the rolling element, in order to extend the analysis to the area that experiences solid friction. A simple analysis model of fluid flow inside the water-lubricated ball bearing is analyzed with CFD, and the flow characteristics at high rotation speeds are presented.

A Study on The Load Capacity of Doubly-Stepped Journal Bearing (공기윤활베어링의 부하용량 증대에 관한 연구)

  • ;;Kim, Hho Jung
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.3 no.1
    • /
    • pp.35-41
    • /
    • 1979
  • In order to improve the load capacity of externally pressurized air-lubeicatedjournal bearings, a new type(doubly-stepped type) bearing was revised and experimented. Through the results of experiment, the load capacity of doubly-stepped bearings was discussed and compared with equivalent conventional circular journal bearings. Results were obtained for speed up to 18000rpm and for supply pressure ratio(Ps/Pa) 4.8,6,7. Compared with equivalent conventional bearings, doubly-stepped bearings resultd a high gain in load capacity. It is also shown that the increasing rate of load capacith increases with decreasing the eccentricity ratio. Furthermore, the increasing rate is higher in the case of great clearanceratio than small dleatance ratio of doubly-stepped bearings. Such an increase in load capacity is confirmed by pressure distributions in the bearings.

Frictional Characteristics of Stainless Steel Ball Bearings Lubricated with Hot Water

  • Lee, Jae-Seon;Kim, Jong-In;Kim, Ji-Ho;Park, Hong-Yune;Zee, Sung-Qunn
    • KSTLE International Journal
    • /
    • v.4 no.2
    • /
    • pp.43-46
    • /
    • 2003
  • Water-lubricated frictional characteristics of a stainless steel ball bearings are not well known compared to the oil-lubricated frictional characteristics. Furthermore a study on friction at a high temperature is rare because the bearing maintenance strategy for water-lubricated or chemicals-lubricated bearings of equipment is generally based on the replacement of the failed bearings-and parts. Ball bearings and ball screw are installed in the power transmission for the newly developing integral reactor and these are lubricated with chemically-controlled pure water at a high temperature and a high pressure. Bearings and power transmitting mechanical elements for an atomic reactor requires high reliability and high performance during the estimated lifetime, and it should be verified. In this paper, experimental research results of the frictional characteristics for water-lubricated ball bearings are presented as a preliminary investigation.

Structural Durability Analysis of Bike Hub Bearing (자전거 허브 베어링의 구조적 내구성 해석에 관한 연구)

  • Han, Moonsik;Cho, Jaeung
    • Journal of the Korean Society of Manufacturing Process Engineers
    • /
    • v.14 no.3
    • /
    • pp.99-104
    • /
    • 2015
  • As riders do not sense damage to hub bearings due to the friction that occurs while riding, unexpected accidents can happen. Hub bearings can also be broken by cracks due to minor impact. Therefore, the vibration analysis of bike hub bearings is thought to be important. Two bike hub bearings were modelled in this study. The bolts at both ends of the bearings were fixed. The standard weight of a Korean man was assumed to be 70Kg, and a force of 700N was applied. As a result of this study, maximum deformations occurred in bolts at both ends of the central axis. Regarding displacement due to natural frequencies, Model 2 had less deformation than Model 1. Using the results of this study, the structural safety of the design of hub bearings can be estimated, and design plans for durable hub bearings can be suggested.