Experimental test of static and dynamic characteristics of tilting-pad thrust bearings

Recently, graphite porous material has been used successfully in an aerostatic bearing. In actual bearing design, it is often necessary to reduce the thickness of porous material to make the bearing smaller. However, a reduction in thickness results in a reduction in the strength of the porous material. In particular, when the diameter of porous material is large, it is difficult to supply the air through the full pad area of porous material because it deforms. Therefore, in this paper, two types of air supply method (the annular groove supply and the hole supply) in a circular aerostatic porous thrust bearing are proposed to avoid the deflection of the bearing surface. The static and dynamic characteristics of aerostatic porous bearing with these air supply methods are investigated theoretically and experimentally. In addition, the effects of a surface restricted layer on the characteristics are clarified.

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Investigation on the static and dynamic characteristics of 3-DOF aerostatic thrust bearings with orifice restrictor

Tribology International ◽

10.1016/j.triboint.2019.06.026 ◽

2019 ◽

Vol 138 ◽

pp. 435-449 ◽

Cited By ~ 2

Author(s):

Jianghai Shi ◽

Hongrui Cao ◽

Xiaoliang Jin

Keyword(s):

Dynamic Characteristics ◽

Static And Dynamic Characteristics ◽

Thrust Bearings

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An Experimental Study of Static and Dynamic Characteristics of a 580mm(22.8in.) Diameter Direct Lubrication Tilting Pad Journal Bearing

Journal of Tribology ◽

10.1115/1.2114929 ◽

2005 ◽

Vol 128 (1) ◽

pp. 146-154 ◽

Cited By ~ 18

Author(s):

Kazunori Ikeda ◽

Toshio Hirano ◽

Tatsuo Yamashita ◽

Makoto Mikami ◽

Hitoshi Sakakida

Keyword(s):

Dynamic Characteristics ◽

Large Scale ◽

Load Capacity ◽

Metal Temperature ◽

Film Pressure ◽

Static And Dynamic Characteristics ◽

Oil Film ◽

Analysis And Design ◽

Tilting Pad ◽

Oil Film Pressure

Direct lubrication tilting pad journal bearings (DLTPJ bearings) have rarely been applied to large-scale rotating machinery, such as turbines or generators, whose journal diameters are more than 500mm. In this paper, static and dynamic characteristics of a 580mm(22.8in.) diameter DLTPJ bearing were studied experimentally using a full-scale bearing test rig. In the static test, distribution of metal temperature, oil film pressure, and bearing loss were measured in changing oil flow rate, with mean bearing pressure ranging up to 2.9MPa. The maximum metal temperature of the DLTPJ bearing was compared to that of a conventional flood lubrication bearing, and it was confirmed that the direct lubrication could increase load capacity. In the dynamic test, spring and damping coefficients of oil film were obtained by exciting the bearing casing that was floated by air bellows. These data will be used for analysis and design of steam turbine rotors and their bearing systems. Also, vibration of pads was investigated because metal failure on upper pads due to vibration has been found in some actual machines. In order to generate oil film pressure on the surface of upper pads, a Rayleigh-step was machined there, and it was confirmed that vibration was reduced by the Rayleigh-step.

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Numerical Investigation of Static and Dynamic Characteristics of Water Hydrostatic Porous Thrust Bearings

International Journal of Automation Technology ◽

10.20965/ijat.2011.p0773 ◽

2011 ◽

Vol 5 (6) ◽

pp. 773-779 ◽

Cited By ~ 6

Author(s):

Yuki Nishitani ◽

◽

Shigeka Yoshimoto ◽

Kei Somaya

Keyword(s):

Porous Material ◽

Dynamic Characteristics ◽

Machine Tools ◽

Measuring Equipment ◽

Load Capacity ◽

Damping Coefficient ◽

Static And Dynamic Characteristics ◽

Thrust Bearings ◽

Hydrostatic Bearings ◽

Aerostatic Bearings

A moving table supported by aerostatic bearings can achieve excellent accuracy of motion because of its noncontact support and, hence, it is used in various precision machine tools and measuring equipment. However, because of low viscosity of air, the damping coefficient of aerostatic bearings is not very high, causing vibration with nanometer-order amplitudes. The accuracy of machine tools and measuring equipment could deteriorate because of this vibration. It is expected that water hydrostatic bearings would have a higher damping coefficient than aerostatic bearings due to the higher viscosity of water. In addition, water, like air, does not pollute the environment. In this paper, the static and dynamic characteristics of water hydrostatic thrust bearings using porous material were numerically investigated and comparedwith conventional pocket hydrostatic bearings with a capillary restrictor. Hydrostatic porous bearings can be easily constructed because the porous material becomes a viscous restrictor itself. It was consequently found that water hydrostatic porous thrust bearings have higher maximum load capacity and slightly lower stiffness than water bearings with a capillary restrictor.

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