Master and Slave Hydrostatic Bearing Systems for Machine Tools

1966 ◽  
Vol 8 (2) ◽  
pp. 152-161 ◽  
Author(s):  
G. P. Kearney
Keyword(s):  
Machine Tools ◽  
Journal Bearing ◽  
Load Capacity ◽  
Design Procedure ◽  
High Load ◽  
General Analysis ◽  
Hydrostatic Bearing ◽  
Hydrostatic Bearings ◽  
Design Calculations ◽  
High Load Capacity

Master and slave systems utilize two types of hydrostatic bearing in order to provide high load capacity in conjunction with non-redundant location by rigid-film hydrostatic bearings. Master bearings are controlled both by applied thrust and by their clearance, and they also control the thrust in the slave bearings which act independently of their own clearances. A journal bearing is used to illustrate analysis of bearing systems, redundant locations, and master and slave systems. A general analysis of master and slave systems is given and a design procedure, advantages, fields of application, and design calculations for individual bearings are outlined in the text and appendixes.

Development of Foil Journal Bearings for High Load Capacity and High Speed Whirl Stability

1982 ◽  
Vol 104 (2) ◽  
pp. 149-156 ◽  
Author(s):  
H. Heshmat ◽  
W. Shapiro ◽  
S. Gray
Keyword(s):  
High Speed ◽  
Journal Bearing ◽  
Load Capacity ◽  
Journal Bearings ◽  
High Load ◽  
Operating Speed ◽  
High Load Capacity

This paper describes the development of two types of air-lubricated foil journal bearings, designed for separate purposes; stability and load capacity. The first was a three-pad configuration, with each pad forming a wedge whose convergence increases with operating speed (of 120,000 rpm max.). The net result is a highly stable bearing at high operating speed. The second was a single pad journal bearing (43.7 mm diameter × 34.9 mm long) that produced a load capacity of 352 KPa (51 psi) at an operating speed of 68,000 rpm.

An Air Layer Modeling Approach for Air and Air/Vacuum Bearings

1997 ◽  
Vol 119 (3) ◽  
pp. 388-392
Author(s):  
J. M. Pitarresi ◽  
K. A. Haller
Keyword(s):  
Load Capacity ◽  
Load Resistance ◽  
High Load ◽  
Air Bearing ◽  
Air Bearings ◽  
Bearing Surface ◽  
Know How ◽  
Modeling Approach ◽  
Vibrational Characteristics ◽  
High Load Capacity

Air layer supported bearing pads, or “air bearings” as they are commonly called, are popular because of their high load capacity and low in-plane coefficient of friction, making them well suited for supporting moving, high accuracy manufacturing stages. Air/vacuum bearings enhance these capabilities by giving the bearing pad load resistance capacity in both the upward and downward directions. Consequently, it is desirable to know how to model the air layer between the bearing pad and the bearing surface. In this paper, a simple finite element modeling approach is presented for investigating the vibrational characteristics of an air layer supported bearing. It was found that by modeling the air layer as a bed of uniform springs who’s stiffness is determined by load-displacement tests of the bearing, a reasonable representation of the response can be obtained. For a bearing supported by air without vacuum, the dynamic response was very similar to that of a freely supported bearing. The addition of vacuum to an air bearing was found to significantly lower its fundamental frequency which could lead to unwanted resonance problems.

A one-stage, high-load capacity separation actuator using anti-friction rollers and redundant shape memory alloy wires

2015 ◽  
Vol 86 (12) ◽  
pp. 125005 ◽  
Author(s):  
Yan Xiaojun ◽  
Huang Dawei ◽  
Zhang Xiaoyong ◽  
Liu Ying ◽  
Yang Qiaolong
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Load Capacity ◽  
High Load ◽  
One Stage ◽  
High Load Capacity

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.

Paper 10: A Hydrodynamic Pocket Journal Bearing

1969 ◽  
Vol 184 (12) ◽  
pp. 70-74
Author(s):  
D. F. Sheldon ◽  
J. P. O'Donoghue ◽  
C. J. Hooke
Keyword(s):  
High Pressure ◽  
Journal Bearing ◽  
Load Capacity ◽  
Control Device ◽  
Experimental Results ◽  
Alternative Mode ◽  
Hydrostatic Bearing ◽  
Operating Range ◽  
Mode Of Operation ◽  
Return Valve

The authors present theoretical and experimental results for a hydrodynamic pocket bearing. The bearing has a geometry similar to that of a conventional hydrostatic bearing, but no control device is incorporated in the supply line other than a non-return valve which prevents the leakage of fluid from those pockets where a pressure is generated. The load capacity of such bearings is greater than that of a circumferentially grooved hydrostatic bearing over the operating range of eccentricity tested by the authors, and is much greater than that of two short hydrodynamic bearings equal to the side sealing lands. Because of this the bearing offers a useful alternative mode of operation for a bearing (externally pressurized) which suffers a loss of its high-pressure oil supply.

Sign in / Sign up

Export Citation Format

Share Document