Self-Acting Foil Bearings Research Articles

2440 ペーパーウェブとローラ間の浮上特性と摩擦特性 : 第 1 報高速搬送領域における特性

In the paper-web transportation systems, the moving web and rotating roller bring the surrounding air between web and roller due to viscosity. As a result, the web-roller interface behaves as the self-acting foil bearings, and it causes a decrease of traction between the web and the roller. Increasing the air film thickness more than the asperity heights of web and roller surfaces, the available traction is nothing more than the fluid film friction which is actually equivalent to the zero-friction. As a decrease in traction in a direct result of air entrainment between web and roller, it is important to predict the friction coefficient including the effects of air film for controlling the traction in many web applications. In this paper, the friction model between paper-web and roller is presented with experimental verifications.

Three-dimensional finite element analysis of self-acting foil bearings

The air bearing thickness and pressure generated when a magnetic tape moves at high speed over a recording head are governed by the coupled equation of motion of the tape and the Reynolds lubrication equation. The steady-state solution to this system of equations is obtained by direct integration using a finite element discretization. Compressibility and slip flow are incorporated into the thin film lubrication equation, and flexural rigidity is retained in the tape motion equation. The model is based on auxiliary dependent variables and uses mixed interpolation involving the four-noded Lagrangian bilinear element and the twelve-noded Adini rectangle. The semidiscrete Galerkin equations are integrated in time using a generalized Newmark method. The head/tape separations for two, fully three-dimensional, recording head geometries are analyzed using the model.

On the behavior of magnetic tape in self-acting foil bearings.

The fluid film thickness between a magnetic tape and a rotating drum is studied experimentally using a laser measuring system under conditions where the fluid film thickness is affected by the bending stiffness of the tape. For comparatively flexible tape cases, the experimental results coincide fairly well with theoretical ones obtained by applying the separation boundary condition. For cases with stiffer tape conditions, the tendency of the experimental results may also be explained well by the theoretical analysis, by introducing the concept of the tangency point condition as well as the infinity point condition for the film pressure generation point.

Study of the Self-Acting Foil Bearings : On the Dynamic Behavior for the Time-Variation of the Tention

Study of the Self-Acting Foil Bearings : On the Dynamic Behavior for the Time-Variation of the Tention

Study of the Self-Acting Foil Bearings : On the Effect of the Finite Width

Study of the Self-Acting Foil Bearings : On the Effect of the Finite Width

Dynamic Response of Self-acting Foil Bearings

A new approach to the analysis of wide foil bearings is investigated. The equation of motion for a finite length of tape is coupled to the transient lubrication equation for the air film between the tape and the recording head. Compressibility and slip flow are retained in the fluid mechanics equation; flexural rigidity and high-speed dynamic effects are retained in the tape equation. The steady-state solution to the coupled equations is obtained as the limiting case of the transient initial value problem. Describing the system equations relative to the undeflected tape (as opposed to conventional foil-bearing theory, which uses the head as the reference surface) permits investigation of noncircular head geometries. In addition, wave propagation effects in the tape and the interaction of waves in the tape with the air-bearing region may be studied.

On controlling the film thickness in self-acting foil bearings

On controlling the film thickness in self-acting foil bearings

On controlling the film thickness in self-acting foil bearings: ESHEL, A. Transactions of the American Society of Mechanical Engineers, Journal of Lubrication Technology, Vol 92, Series F, No 2 (Apr 1970) pp 358–362

On controlling the film thickness in self-acting foil bearings: ESHEL, A. Transactions of the American Society of Mechanical Engineers, Journal of Lubrication Technology, Vol 92, Series F, No 2 (Apr 1970) pp 358–362

On Controlling the Film Thickness in Self-Acting Foil Bearings

Abstract Some factors useful in overcoming excessive air gaps in foil bearings are investigated. Since the gaps of interest are small, the foil bearing equations are modified to include the effects of the molecular mean free path. It is shown that by small corners in the solid wall, one can reduce the air film thickness considerably. A change in curvature with continuous slope has also a marked effect on the film thickness. Theoretical prediction curves allowing the calculation of the air gap as a function of corner angle, change in radius of curvature, and the molecular mean free path are presented.

An experimental study of high-speed rotors supported by air-lubricated foil bearings—Part 1: Rotation in pressurised and selfacting foil bearings : L. Light, JOLT, 91, Ser. F, (3) (1969) 477–493; 16 figs., 27 refs.

An experimental study of high-speed rotors supported by air-lubricated foil bearings—Part 1: Rotation in pressurised and selfacting foil bearings : L. Light, JOLT, 91, Ser. F, (3) (1969) 477–493; 16 figs., 27 refs.

An Experimental Study of High-Speed Rotors Supported by Air-Lubricated Foil Bearings—Part 1: Rotation in Pressurized and Self-Acting Foil Bearings

A high-speed rotor, supported by an air-lubricated foil bearing, is rotated in both the vertical and horizontal attitudes at speeds in excess of 60,000 rpm. The rotor is stable and free from “half-frequency” or “fractional-frequency” whirl instability encountered in conventional gas bearings. External pressurization is applied to separate the foil surfaces from the journal during the initial and final stages of rotation, with adequate self-acting support and foil separation established at relatively low transition speeds. In the pressurized mode of operation, the system is characterized by a series of ultra-harmonic resonances, of sharply defined frequencies, related by fractions to speeds of synchronous resonance. In the self-acting mode of operation, the response of the system to residual imbalance is influenced by both the foil bearing and by the pressurized thrust bearings. The magnitude of the air gap (clearance) is determined at various rotational speeds and compared with theoretically predicted results. The temperature rise of the foil with speed is measured at various locations in order to assess its contribution to clearance growth. The journal and foil surfaces are examined and it is found that the foil bearing is endowed with excellent wipe-wear characteristics.

Self-acting foil bearings of infinite width. (66-Lub-8) : E. J. Barlow, pp. 341–345; 6 figs., 9 refs.

Self-acting foil bearings of infinite width. (66-Lub-8) : E. J. Barlow, pp. 341–345; 6 figs., 9 refs.

Derivation of governing equations for selfacting foil bearings. (66-Lub-18) : E. J. Barlow, pp. 334–340; 5 figs. 7 refs.

Derivation of governing equations for selfacting foil bearings. (66-Lub-18) : E. J. Barlow, pp. 334–340; 5 figs. 7 refs.

Discussion: “Derivation of Governing Equations For Self-Acting Foil Bearings” (Barlow, E. J., 1967, ASME J. Lubr. Technol., 89, pp. 334–339)

Discussion: “Derivation of Governing Equations For Self-Acting Foil Bearings” (Barlow, E. J., 1967, ASME J. Lubr. Technol., 89, pp. 334–339)

Closure to “Discussion of ‘Derivation of Governing Equations For Self-Acting Foil Bearings’” (1967, ASME J. Lubr. Technol., 89, p. 339)

Closure to “Discussion of ‘Derivation of Governing Equations For Self-Acting Foil Bearings’” (1967, ASME J. Lubr. Technol., 89, p. 339)

Derivation of Governing Equations For Self-Acting Foil Bearings

Contained is the derivation of the equations for the self-acting foil bearing. These equations include the effects of bending stiffness of the tape and of compressibility of the lubricant. They are nonlinear, and the boundary conditions are divided equally between the two ends of the tape. These complications even make obtaining numerical solutions difficult. Linearized solutions are derived for large wrap angles neglecting the bending stiffness of the tape.

Self-Acting Foil Bearings of Infinite Width

In this report, the minimum gap between a rigid cylinder and a moving foil (or between a rotating cylinder and a stationary foil) is determined as a function of the wrap angle as well as of the foil speed and tension, the cylinder radius, and the viscosity of the lubricant.

Discussion: “An Investigation of Self-Acting Foil Bearings” (Ma, J. T. S., 1965, ASME J. Basic Eng., 87, pp. 537–546)

Discussion: “An Investigation of Self-Acting Foil Bearings” (Ma, J. T. S., 1965, ASME J. Basic Eng., 87, pp. 537–546)

Closure to “Discussion of ‘An Investigation of Self-Acting Foil Bearings’” (1967, ASME J. Basic Eng., 89, p. 239)

Closure to “Discussion of ‘An Investigation of Self-Acting Foil Bearings’” (1967, ASME J. Basic Eng., 89, p. 239)

An investigation of self-acting foil bearings : J. T. S. Ma, Trans. ASME, 87D (4) (1965) 831–836. ( J. Basic Eng.)

An investigation of self-acting foil bearings : J. T. S. Ma, Trans. ASME, 87D (4) (1965) 831–836. ( J. Basic Eng.)