A one piece hydrodynamic bearing which can include hydrostatic support features. The pads are supported on a single thin web for pivoting on a support structure which can include one or more beam-like members. The bearings may have hydrostatic and active control attributes and is very attractive in cryogenic applications where it is very difficult to prevent leakage in conventional hydrostatic tilt pad bearings. The hydrostatic feed through the post eliminates this problem completely and prevents the fretting at the pivots common with conventional tilt pad bearings. A cavity provided under a pad support membrane can be used as an active control device. The pressure can cause the bearing set or assembly clearance to be reduced thus providing better damping and centering capability. The preload in the pad can be actively controlled in this manner. The pad has a limiting device to prevent a negative pre-load condition from occurring. This active control of bearing clearance can allow bearings to operate at large spreads in temperatures.

Hydrostatic and active control movable pad bearing

A rotary type electrostatic spray painting device comprising a rotary shaft and a spray head fixed onto the front end of the rotary shaft. Paint is fed onto the cup shaped inner wall of the spray head. The rotary shaft is supported by a single thrust air bearing and a pair of radial air bearings. The thrust air bearing comprises a stationary annular plate and a pair of runners fixed onto the rotary shaft and arranged on each side of the annular plate. Each of the side walls of the annular plate comprises a central wall region facing the corresponding runner, and a peripheral wall region located radially outwardly from the runners. A plurality of air outflow bores is formed on the side walls of the annular plate in the central wall region for feeding air into the clearance between the annular plate and the runners. A plurality of pressure balancing bores are formed in the annular plate and arranged in the peripheral wall region. An electrode, continuously contacting the rear end of the rotary shaft, is provided. A negative high voltage is applied to the housing of the paint device. In addition, the negative high voltage is also applied to the spray head via the electrode and the rotary shaft.

Rotary type electrostatic spray painting device

An extensive survey of the papers pertaining to thermal effects in hydrodynamic bearings, particularly the slider/thrust bearings, is presented with a summary of the important contributions of leading researchers and designers Presented at the 41st Annual Meeting in Toronto, Ontario, Canada May 12–15, 1986

A Review of Thermal Effects in Hydrodynamic Bearings Part I: Slider and Thrust Bearings

The finite length pressure dam step bearing is analyzed neglecting step inertia effects, but including the effects of turbulence over the entire bearing surface. Load curves for sample step bearing designs are given along with stiffness and damping coefficients. Bearing stability threshold curves for various pressure dam bearing geometries are compared to plain journal, two-axial groove and grooved lower-half bearings. The optimum Sommerfeld number range for designing a pressure dam bearing to increase stability is S > 2.0. At S values of this order, the recommended film thickness ratio for favorable stability is between 3.0 and 6.0 with the step located at 145° in the direction of rotation from the positive horizontal axis. Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in Minneapolis, Minnesota, October 24–26, 1978

Analysis of Step Journal Bearings—Finite Length, Stability

In order to effect a seal; a porous material which comprises one side of two opposing surfaces is used to restrict and evenly distribute externally pressurized gas, liquid, steam, etc. between the two surfaces, exerting a force which is opposite the forces from pressure differences or springs trying to close the two faces together and so may create a non contact seal that is more stable and reliable than hydrodynamic seals currently in use.

Air bearing for use as seal

Improved Method for Numerical Solutions of the General Incompressible Fluid Film Lubrication Problem

A Numerical Solution for the Incompressible Hybrid Journal Bearing With Cavitation

A porous hydrostatic bearing having self-lubricating bearing pads mounted in a plurality of adjustably mounted bearing shoes. The use of such a bearing in conjunction with the gas source taking the form of the system working medium allows for the use of this bearing in a cryogenic atmosphere.

Porous hydrostatic bearing

An analytical program was conducted to establish recommended types of gas-lubricated journal bearings for use in miniature cryogenic turbomachinery. Very high rotative speeds, and the limiting damping properties of gas, indicated that fractional frequency whirl is prevalent, and the most difficult problem to overcome. Of the many journal bearing types investigated, the tilting pad hydro-dynamic and porous hydrostatic journal bearings were suited to the application. A novel spring mounted, three shoe, porous hydrostatic bearing is discussed in terms of design and experimental results. A 1/2 inch diameter journal bearing is subjected to loading and speeds to 700 grams and 65,000 rpm, respectively. Excellent performance in terms of load capacity, power loss, and flow are indicated. Orbit motions of the floated bearing with respect to the supported shaft demonstrate desirable stability characteristics for the range of tests. Presented as an American Society of Lubrication Engineers paper at the ASME/ASLE Lubr...

A Porous Hydrostatic Gas Bearing for Use in Miniature Turbomachinery

Gas lubricated hybrid journal bearings with external pressure, noting load capacity and stability in steady state and dynamic analyses

W. Shapiro

Papers

Improved Method for Numerical Solutions of the General Incompressible Fluid Film Lubrication Problem

A Numerical Solution for the Incompressible Hybrid Journal Bearing With Cavitation

Porous hydrostatic bearing

A Porous Hydrostatic Gas Bearing for Use in Miniature Turbomachinery

Steady-State and Dynamic Analyses of Gas-Lubricated Hybrid Journal Bearings