Static and Dynamic Characteristics of Aerostatic Circular Porous Thrust Bearings (Effect of the Shape of the Air Supply Area)

2000 ◽  
Vol 123 (3) ◽  
pp. 501-508 ◽  
Author(s):  
S. Yoshimoto ◽  
K. Kohno
Keyword(s):  
Porous Material ◽  
Dynamic Characteristics ◽  
Thrust Bearing ◽  
Aerostatic Bearing ◽  
Bearing Surface ◽  
Static And Dynamic Characteristics ◽  
Thrust Bearings ◽  
Porous Bearing ◽  
Air Supply ◽  
Bearing Design

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.

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

2011 ◽  
Vol 5 (6) ◽  
pp. 773-779 ◽  
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.

The Static and Dynamic Characteristics of the Spiral-Grooved Thrust Bearing

1965 ◽  
Vol 87 (3) ◽  
pp. 547-555 ◽  
Author(s):  
S. B. Malanoski ◽  
C. H. T. Pan
Keyword(s):  
Phase Angle ◽  
Dynamic Characteristics ◽  
Thrust Bearing ◽  
Load Capacity ◽  
Radius Ratio ◽  
Oscillatory Motion ◽  
Static And Dynamic Characteristics ◽  
Thrust Bearings ◽  
Rotor Bearing ◽  
Oscillating Motion

A generalized analysis for spiral-grooved thrust bearings is presented. The effects of local radius are considered. For the same grooving geometry and the same inside-to-outside radius ratio, the inflow design is shown to be superior in both stiffness and load capacity. The analysis also treats a relative, transverse, oscillatory motion of the bearing surfaces. Both the magnitude and phase angle (in the temporal sense) of the bearing reaction are dependent on the frequency of the motion. The results for the oscillating motion reveal the possibility of a self-excited, rotor-bearing instability. The criterion for determining the onset of this type of instability is given.

Static Characteristics of Aerostatic Thrust Bearings With Multiple Porous Inlet Ports

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Takako Hosokawa ◽  
Kei Somaya ◽  
Masaaki Miyatake ◽  
Shigeka Yoshimoto
Keyword(s):  
Porous Material ◽  
Thrust Bearing ◽  
Liquid Crystal Display ◽  
Manufacturing Cost ◽  
Static Characteristics ◽  
Bearing Surface ◽  
Thrust Bearings ◽  
Precision Measuring ◽  
Essential Components ◽  
Precision Machine Tools

Aerostatic porous bearings have been applied successfully to various precision devices, such as precision machine tools and precision measuring equipment, to achieve higher accuracy of motion. Recently, large aerostatic porous thrust bearings have been used as essential components in a lithography machine for large liquid crystal display (LCD) glasses. Conventional aerostatic porous bearings are made of porous material that covers the whole of the bearing surface area, requiring a large piece of such material for large bearings. However, making large pieces of porous material requires the use of a large electric furnace, which is a very expensive part of the bearing's manufacturing cost. To overcome this problem, this paper proposes an aerostatic thrust bearing with multiple porous inlet ports. The proposed bearing has a number of small porous inlet ports on the bearing surface, thereby avoiding the need for large electric furnaces. The static characteristics of the proposed bearings are investigated numerically and experimentally. The results show that the proposed aerostatic thrust bearing is potentially very useful for the manufacture of large aerostatic thrust bearings, where it would have advantages over conventional aerostatic porous thrust bearings.

The Dynamic Optimization Analysis of High-Speed Hybrid Thrust Bearing

2010 ◽  
Vol 118-120 ◽  
pp. 507-511
Author(s):  
Kai Sun ◽  
Lan Wang ◽  
Xin Jun Zhao
Keyword(s):  
Dynamic Optimization ◽  
Dynamic Characteristics ◽  
High Speed ◽  
Thrust Bearing ◽  
Orifice Diameter ◽  
Optimization Analysis ◽  
Angular Misalignment ◽  
Thrust Bearings ◽  
Supply Pressure ◽  
Dynamic Moment

In this paper, the dynamic characteristics of high-speed hybrid thrust bearing with four-recesses are optimized for different orifice diameter and supply pressure at a given speed condition, the dynamic moment coefficients of hybrid thrust bearing are analyzed, considering the thrust collar angular misalignment case to determine the optimization of orifice diameter and supply pressure under a given speed. The results provide certain reference to the hybrid thrust bearings used in high speed precision spindle.

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

2015 ◽  
Vol 7 (7) ◽  
pp. 168781401559387 ◽  
Author(s):  
Annan Guo ◽  
Xiaojing Wang ◽  
Jian Jin ◽  
Diann Y Hua ◽  
Zikai Hua
Keyword(s):  
Dynamic Characteristics ◽  
Experimental Test ◽  
Static And Dynamic Characteristics ◽  
Thrust Bearings ◽  
Tilting Pad
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