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.

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.

Advancements in the Performance of Aerodynamic Foil Journal Bearings: High Speed and Load Capability

1994 ◽  
Vol 116 (2) ◽  
pp. 287-294 ◽  
Author(s):  
H. Heshmat
Keyword(s):  
High Speed ◽  
Room Temperature ◽  
Journal Bearing ◽  
Load Capacity ◽  
Ambient Pressure ◽  
Journal Bearings ◽  
Test Results ◽  
Rotor Speed ◽  
Turbine Wheel ◽  
Dynamic Analyses

An advanced-design, aerodynamic, air-lubricated foil journal bearing achieved a landmark speed of 2200 cps (132,000 rpm) and a major breakthrough in load performance of 673.5 kPa (97.7 psi). At 20°C (68°F) room temperature, normal ambient pressure, 995 cps (59,700 rpm) rotor speed, and with bearing projected pad area of 1081 mm2 (1.675 in2), the bearing demonstrated a load capacity of 727.8 N (163.6 lb). The bearing also exhibited low heat generation, with about 40°C (104°F) average side leakage temperature rise. For this demonstration, a highspeed spindle utilizing a pair of 35-mm (1.375-in.) bearings and supporting a test rotor with a mass of 1.545 kg (weighing 3.41 lb) and overall length of 211 mm (8.3 in.) was successfully taken to the limiting speed of the test apparatus. This speed was set by the maximum sound velocity (Mach 1) in the spindle’s turbine wheel. The rotor/bearing speed of 4.62 × 106 DN is beyond the capability of any advanced oil-lubricated ball bearings or conventional gas-lubricated bearings. The net result is a highly stable bearing at high operating speed. This paper presents the development of this air-lubricated foil journal bearing, the operational procedures used during testing, test results (dynamic analyses), and load performance characteristics.

Integrated Simulation and Structure Optimization of Rigid-Flexible Coupling Mechanical Leg Based on PATRAN, NASTRAN and ADAMS

2014 ◽  
Vol 614 ◽  
pp. 16-18 ◽  
Author(s):  
Wen Tao Zhao ◽  
Yong Zheng Li ◽  
Sen Wang
Keyword(s):  
High Speed ◽  
Load Capacity ◽  
Structure Optimization ◽  
High Load ◽  
Stress And Strain ◽  
Intermediate Structure ◽  
Light Weight ◽  
Flexible Coupling ◽  
Integrated Simulation ◽  
High Load Capacity

According to the requirements of light weight, low-energy and short development period under the conditions that leg mobile robots exert high movement adaptability, high speed and high load capacity, integrated simulation and structure optimization of rigid-flexible coupling mechanical leg are proposed based on PATRAN, NASTRAN and ADAMS. Firstly, .bdf file is obtained via PATRAN. Secondly, MNF is acquired via NASTRAN. Thirdly, the rigid-flexible coupling mechanical leg is established, the motion of mechanical leg based on the trajectory planning is implemented, and integrated simulation is completed via ADAMS. Finally, Structure optimization is processed step-by-step and completed whenever intermediate structure meets the stress and strain requirements. The example is presented that illustrates advantages of the proposed method.

scholarly journals Improvement of Tilting-Pad Journal Bearing Operating Characteristics by Application of Eddy Grooves

Lubricants ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 18
Author(s):  
Eckhard Schüler ◽  
Olaf Berner
Keyword(s):  
High Speed ◽  
Journal Bearing ◽  
Load Capacity ◽  
Fluid Film ◽  
Operating Characteristics ◽  
Fluid Film Bearings ◽  
Tilting Pad ◽  
Bearing Load ◽  
Bearing Loads ◽  
Tilting Pad Journal Bearing

In high speed, high load fluid-film bearings, the laminar-turbulent flow transition can lead to a considerable reduction of the maximum bearing temperatures, due to a homogenization of the fluid-film temperature in radial direction. Since this phenomenon only occurs significantly in large bearings or at very high sliding speeds, means to achieve the effect at lower speeds have been investigated in the past. This paper shows an experimental investigation of this effect and how it can be used for smaller bearings by optimized eddy grooves, machined into the bearing surface. The investigations were carried out on a Miba journal bearing test rig with Ø120 mm shaft diameter at speeds between 50 m/s–110 m/s and at specific bearing loads up to 4.0 MPa. To investigate the potential of this technology, additional temperature probes were installed at the crucial position directly in the sliding surface of an up-to-date tilting pad journal bearing. The results show that the achieved surface temperature reduction with the optimized eddy grooves is significant and represents a considerable enhancement of bearing load capacity. This increase in performance opens new options for the design of bearings and related turbomachinery applications.

An Approximate THD Theory for Journal Bearings

1990 ◽  
Vol 112 (2) ◽  
pp. 224-229 ◽  
Author(s):  
G. Gupta ◽  
C. R. Hammond ◽  
A. Z. Szeri
Keyword(s):  
Journal Bearing ◽  
Load Capacity ◽  
Pressure Coefficient ◽  
Journal Bearings ◽  
Maximum Pressure ◽  
Substantial Agreement ◽  
Interactive Mode ◽  
Lubricant Flow ◽  
Bearing Load ◽  
Sophisticated Model

The aim of this paper is to make available to the industrial designer results of the thermohydrodynamic theory of journal bearings, by providing a simplified, yet accurate model of journal bearing lubrication that can be implemented on a personal computer and be used in an interactive mode. The simplified THD theory we propose consists of two coupled ordinary differential equations for pressure and energy and an algebraic equation for viscosity, which are to be solved iteratively. Bearing load capacity, maximum bearing temperature, maximum pressure, coefficient of friction and lubricant flow rate calculated from this simplified theory compare well with results from a more sophisticated model. We also make comparisons with experimental data on full journal bearings, demonstrating substantial agreement between experiment and simplified theory.

Influence of geometric parameters and operating conditions on the thermohydrodynamic behaviour of plain journal bearings

2000 ◽  
Vol 214 (5) ◽  
pp. 445-457 ◽  
Author(s):  
I Pierre ◽  
M Fillon
Keyword(s):  
High Speed ◽  
Journal Bearing ◽  
Three Dimensional ◽  
Journal Bearings ◽  
Operating Conditions ◽  
Thermal Dissipation ◽  
Radial Clearance ◽  
Geometric Factors ◽  
Essential Components ◽  
Mass Flowrate

Hydrodynamic journal bearings are essential components of high-speed machinery. In severe operating conditions, the thermal dissipation is not a negligible phenomenon. Therefore, a three-dimensional thermohydrodynamic (THD) analysis has been developed that includes lubricant rupture and re-formation phenomena by conserving the mass flowrate. Then, the predictions obtained with the proposed numerical model are validated by comparison with the measurements reported in the literature. The effects of various geometric factors (length, diameter and radial clearance) and operating conditions (rotational speed, applied load and lubricant) on the journal bearing behaviour are analysed and discussed in order to inform bearing designers. Thus, it can be predicted that the bearing performance obtained highly depends on operating conditions and geometric configuration.

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.

Steady-State and Dynamic Behaviour of Multi-Recess Hybrid Oil Journal Bearings

1979 ◽  
Vol 21 (5) ◽  
pp. 345-351 ◽  
Author(s):  
M. K. Ghosh ◽  
B. C. Majumdar ◽  
J. S. Rao
Keyword(s):  
Perturbation Theory ◽  
Steady State ◽  
Theoretical Analysis ◽  
Dynamic Behaviour ◽  
Journal Bearing ◽  
Load Capacity ◽  
Journal Bearings ◽  
Time Dependent ◽  
Damping Coefficients ◽  
Stiffness And Damping

A theoretical analysis of the steady-state and dynamic characteristics of multi-recess hybrid oil journal bearings is presented. A perturbation theory for small vibrations is used to solve an incompressible, finite journal bearing with a time-dependent term. Load capacity, attitude angle, friction parameter, stiffness and damping coefficients are evaluated for a capillary-compensated bearing.

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