Analysis of a Hydrodynamic Herringbone Grooved Journal Bearing Considering Cavitation

1999 ◽  
Vol 122 (1) ◽  
pp. 103-109 ◽  
Author(s):  
G. H. Jang ◽  
D. I. Chang
Keyword(s):  
Journal Bearing ◽  
Load Capacity ◽  
Disk Drive ◽  
Maximum Load ◽  
Spindle Motor ◽  
Groove Width ◽  
Positive Pressure ◽  
Width Ratio ◽  
Cavitation Region ◽  
Coordinate Mapping

The Reynolds equation, incorporating Elrod’s cavitaton algorithm, is discretized on a rectangular grid in computational space through coordinate mapping in order to accurately analyze a herringbone grooved journal bearing of a spindle motor in a computer hard disk drive. The pressure distribution and cavitation area are determined by using the finite volume method. Predicted results are compared to experimental data of previous researchers. It was found that positive pressure is developed within the converging section of the bearing and that a cavity occurs in the diverging section. Cavitation has been neglected in the previous analyses of the herringbone grooved bearing. Load capacity and bearing torque are increased due to the increase of eccentricity and L/D and the decrease of the groove width ratio. The maximum load capacity was found to occur at a groove angle of 30 degrees while bearing torque remains constant due to the variation of the groove angle. The cavitation region is significantly decreased with the inclusion of herringbone grooves. However, the region increases with the increase of the eccentricity, L/D, groove angle and the rotational speed and the decrease of the groove width ratio. [S0742-4787(00)01401-6]

Rayleigh Step Journal Bearing: Part 1—Compressible Fluid

1968 ◽  
Vol 90 (1) ◽  
pp. 271-280 ◽  
Author(s):  
B. J. Hamrock
Keyword(s):  
Compressible Fluid ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Load Capacity ◽  
Maximum Load ◽  
Pressure Profile ◽  
Clearance Ratio ◽  
Attitude Angle ◽  
Step Parameters ◽  
Bearing Part

A linearized PH solution to the Reynolds equation was obtained while neglecting side leakage. The analysis was divided into two parts—the step and ridge regions. The pressure profile across the step and ridge region of the various pads which are placed around the journal was obtained from the linearized PH Reynolds equation. Knowing the pressure, the load components and attitude angle were calculated. The resulting equations were found to be a function of the bearing parameters (the eccentricity and compressibility number) and the step parameters (ratio of the stepped clearance to the ridge clearance, ratio of the angle extended by the ridge to the angle extended by the pad, and number of pads placed around the journal). The maximum load capacity can be determined by numerically differentiating the load with respect to the step bearing parameters while finding where the slope is zero. A series of data was run while varying the bearing parameters. The attitude angle was calculated for the various cases which were run.

Static Characteristics of the Regular and Reversible Rotation Type Herringbone Grooved Journal Bearing

1989 ◽  
Vol 111 (3) ◽  
pp. 484-490 ◽  
Author(s):  
Nobuyoshi Kawabata ◽  
Yasumi Ozawa ◽  
Shuji Kamaya ◽  
Yutaka Miyake
Keyword(s):  
Numerical Analysis ◽  
Journal Bearing ◽  
Load Capacity ◽  
Maximum Load ◽  
Radial Load ◽  
Static Characteristics ◽  
Oil Film ◽  
New Type ◽  
Load Component ◽  
Reversible Rotation

A new type herringbone grooved journal bearing, which produces an oil film bearing pressure with a shaft or bearing rotation in either direction, is proposed in this paper. A numerical analysis of the bearing parameters using the narrow groove theory and the Gu¨mbel condition confirmed that the load capacity of this bearing and the radial load component (related to stability) do not differ greatly from those of a conventional bearing. The values of the bearing parameters which give maximum load capacity, and the values of the load capacity and its direction angle are also determined numerically for the case of either grooved member or smooth member rotation.

Rayleigh Step Journal Bearing, Part II—Incompressible Fluid

1969 ◽  
Vol 91 (4) ◽  
pp. 641-650 ◽  
Author(s):  
B. J. Hamrock ◽  
W. J. Anderson
Keyword(s):  
Theoretical Analysis ◽  
Film Thickness ◽  
Journal Bearing ◽  
Load Capacity ◽  
Maximum Load ◽  
Single Step ◽  
Thickness Ratio ◽  
Infinite Length ◽  
One Step ◽  
Bearing Part

A theoretical analysis of the pressure distribution, load, capacity, and attitude angle for a single-step concentric as well as a multistep infinite length eccentric Rayleigh step journal bearing is performed. The results from the single-step concentric analysis indicated that the maximum load capacity is obtained when the film thickness ratio is 1.7 and the ratio of the angle subtended by the ridge to the angle subtended by the pad is 0.35. The results from the infinite length eccentric analysis indicated that one step placed around the journal was optimal. For eccentricity ratios greater than or equal to 0.2 the maximum load occurred for a bearing without a step or a Sommerfeld bearing. For eccentricity ratios less than 0.2 the optimal film thickness ratio is 1.7 while there are three optimal ratios of angle subtended by the ridge to the angle subtended by the pad of 0.4, 0.45, and 0.5 depending on whether load capacity or stability or both load capacity and stability is more important in the application being considered.

scholarly journals Numerical Modeling on the Compliance and Load Capacity of a Two-Row Aerostatic Journal Bearing with Longitudinal Microgrooves in the Inter-Row Zone

2021 ◽  
Vol 11 (12) ◽  
pp. 5714
Author(s):  
Vladimir Kodnyanko ◽  
Stanislav Shatokhin ◽  
Andrey Kurzakov ◽  
Yuri Pikalov ◽  
Iakov Pikalov ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Journal Bearing ◽  
Load Capacity ◽  
Finite Difference Methods ◽  
Injection Pressure ◽  
Maximum Load ◽  
Double Row ◽  
Environmental Friendliness ◽  
High Durability ◽  
Air Lubrication

Aerostatic bearings are attractive, with minimal friction losses, high durability, and environmental friendliness. However, such designs have a number of disadvantages, including low load-bearing capacity and high compliance due to high air compressibility and limited injection pressure. The article proposes a double-row aerostatic journal bearing with an external combined throttling system and longitudinal microgrooves in the inter-row zone. It is hypothesized that the use of microgrooves will reduce the circumferential flows of compressed air, as a result of which the compliance should decrease and the bearing capacity should increase. To test the hypothesis, we carried out the mathematical modeling, calculations, and theoretical study of stationary operation modes of the bearing for small shaft eccentricities in the vicinity of the central equilibrium position of the shaft and bearing capacity for arbitrary eccentricities. Formulas were obtained for the numerical evaluation of compliance for bearings with a smooth bushing surface and with longitudinal microgrooves. Iterative finite-difference methods for evaluating the fields of the squared pressure are proposed, on the basis of which the load capacity of the bearings is calculated. Experimental verification of the bearing’s theoretical characteristics was carried out, which showed satisfactory agreement between the compared data. The study of the compliance and load capacity of a microgroove bearing yielded impressive results. We show that the positive effect from the application of the improvement begins to manifest itself already at four microgrooves; the effect becomes significant at six microgrooves, and at twelve or more microgrooves, the circumferential flows in the bearing gap practically disappear; therefore, the bearing characteristics can be calculated on the basis of one-dimensional models of air lubrication longitudinal flow. Calculations have shown that for a length of L = 1, the maximum load capacity of a bearing with microgrooves is 1.5 times higher than that of a conventional bearing; for L ≥ 1.5, the bearing capacity increases twice or more. The result obtained allows us to recommend the proposed improvement for practical use in order to increase the load capacity of aerostatic journal bearings significantly.

Determination of the Maximum Load Capacity of a Gas Foil Journal Bearing

2021 ◽  
Author(s):  
V. V. Volkov-Muzylev ◽  
Yu. A. Borisov ◽  
A. S. Pugachuk ◽  
V. N. Beschastnykh
Keyword(s):  
Journal Bearing ◽  
Load Capacity ◽  
Maximum Load

Determination of the Integration Constant for Squeeze Films in Infinitely Long Journal Bearings

1970 ◽  
Vol 92 (1) ◽  
pp. 179-180
Author(s):  
D. C. Kuzma
Keyword(s):  
Arbitrary Constant ◽  
Journal Bearing ◽  
Load Capacity ◽  
Journal Bearings ◽  
Integration Constant ◽  
Squeeze Film ◽  
Positive Pressure ◽  
Limiting Case

The complete film solution for the squeeze film in an infinitely long journal bearing contains an arbitrary constant. When only positive pressure regions are retained, this constant influences the load capacity. Several different values have been used for this constant. Its value is determined here so that the infinitely long journal bearing is the limiting case of the finite journal bearing.

Design of Novel Hydrodynamic Grooved Journal Bearing with Dual-Layer Herringbone-Grooved Patterns

2015 ◽  
Vol 764-765 ◽  
pp. 239-243
Author(s):  
Chien Sheng Liu ◽  
Min Kai Lee ◽  
Ying Chi Chuo
Keyword(s):  
Journal Bearing ◽  
Load Capacity ◽  
Spindle Motor ◽  
Field Analysis ◽  
Analysis Software ◽  
Current Group ◽  
Cooling Fans ◽  
Flow Field Analysis ◽  
High Load Capacity

Due to that the load capacity of the conventional herringbone-grooved cylindrical journal bearing (HGJB) decreases significantly with a decreasing dimension, a requirement exists for miniature HGJB with high load capacity in miniaturized spindle motor applications. This paper investigates the design and characterization of a novel HGJB using dual-layer herringbone-grooved patterns for small spindle motors and cooling fans. In contrast to conventional HGJBs, the proposed HGJB contains another set of herringbone-grooved pattern on its outer surface. The performance of the proposed HGJB is characterized numerically using flow field analysis software. Results show that compared to the conventional HGJB presented by the current group in a previous study, the proposed HGJB can improve the load capacity by 53.7% of the previous value.

Static Characteristics of a Slot-Entry Gas Journal Bearing With Feeding Holes

1988 ◽  
Vol 110 (4) ◽  
pp. 587-591 ◽  
Author(s):  
S. Yoshimoto
Keyword(s):  
Gas Flow ◽  
Journal Bearing ◽  
Load Capacity ◽  
Maximum Load ◽  
Viscous Resistance ◽  
Narrow Gap ◽  
Static Characteristics ◽  
Theoretical Predictions ◽  
The Finite Difference Method ◽  
Gas Journal Bearing

This paper describes the static characteristics of a slot-entry gas journal bearing with feeding holes. Gas flow in this bearing is restricted first by inflow resistance when gas rapidly flows into the narrow gap of the slot region from isolated feeding holes, and then, restricted more by viscous resistance in the slot region. Therefore, the maximum load capacity and stiffness in this type of bearing can be easily obtained even in a very small bearing clearance of less than 10 μm because gas flow entering the journal can be restricted to a very small amount. Here, the static characteristics of this type of bearings are determined numerically by using the finite difference method. The validity of the theoretical predictions is confirmed by comparison with the experimental results.

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