Bearings – Rotary bearing – Hydraulic or pneumatic bearing support
Reexamination Certificate
1999-09-09
2001-03-06
Hannon, Thomas R. (Department: 3682)
Bearings
Rotary bearing
Hydraulic or pneumatic bearing support
Reexamination Certificate
active
06196721
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to bearing race vibration dampening. More specifically, the invention is a bearing race and ring assembly which significantly reduces mechanical wear attributed to bearing vibrations by undulating surface lubrication.
2. Description of Related Art
Various bearing races of conventional construction, are used extensively in industry, particularly in rotating machinery. The most significant utility of most bearing races is the application of the bearing races as squeeze film dampers (SFDs). The conventional construction of the squeeze film bearing typically includes a circular bore hydrodynamic bearing, however, the journal does not rotate but oscillates within the circular bore while separated from it by a fluid film. As such, a certain amount of viscous fluid (i.e. an oil lubricant) must be continuously fed to the damper interface to compensate for end leakage. The Reynolds equation has been typically used to predict the oil film pressure assuming constant pressure across the film, constant fluid properties and laminar flow, while ignoring cavitation and inertia effects. Of the lesser researched effects in the SFD fluid film pressures are those caused by Bernoulli effects, that is fluid film pressures are greater in the areas adjacent to a minimum film thickness and conversely. The fluid force in SFD's are notably nonlinear in areas of increased eccentricity ratio, however with reduced viscous dampening. Some of the conventional methods described herein, illustrates some or all of the aforementioned characteristics, however without the benefit of the sinusoidal viscous damper system as herein described. A viscous dampening system which provides enhanced vibration dampening across an expanded viscous surface area or film for reducing mechanical wear and cyclical material fatigue is lacking in conventional viscous dampening ball and roller bearing systems.
For example, U.S. Pat. No. 1,386,255 issued to Hindle et al. discloses a conventional bearing having an interior ring with a slightly greater diameter than the external diameter of the outer ball race concentrically disposed around the outer periphery of the ball race member. The ring is provided with distance pieces arranged at intervals around its outer periphery, those on the inner periphery engaging the outer ball race member and those on the outer periphery with the housing of the bearing. U.S. Patent issued to Jungstrom (U.S. Pat. No. 1,965,293) is of similar construction to that of Hindle et al., except the bearing casing is a dual bearing casing which provide greater bearing surface contact with the rotor shaft.
U.S. Pat. No. 5,201,585 issued to Gans et al. discloses a fluid film bearing having a squeeze film damper tailored to the dynamic vibration of a turbomachine. An inner cylindrical bearing sleeve has a bearing surface immediately adjacent the journal surface. An array of recesses are disposed at the bearing surface which allows fluid for the fluid film to pass through the journal bearing sleeve and into a shallow annular film volume between the bearing surface and the rotor shaft.
U.S. Pat. No. 5,380,100 issued to Yu discloses a squeeze film damper covered by torus shells. The torus shells provide the stiffness within a clearance of the squeeze film, and serve to separate the damping fluid from its lubricating environment. The damper outer ring and the damper inner ring are machined each with a pair of half torus shells which are welded together as a single integrated structure. The fluid is transmitted via drip holes disposed in selective areas within the bearing housing. Other U.S. Patents of general relevance to that of the instant invention are those issued to Robertson (U.S. Pat. No. 2,101,346), Robinson (U.S. Pat. No. 3,513,480), and Riegger et al. (U.S. Pat. No. 4,901,014) which disclose conventional features such as bearing mounting and alignment.
Soviet Union Patent No. 1229472 discloses a bearing damping unit comprising two bushes with opposing trapezoidal teeth mounted concentrically with clearance and having self wedging elements between teeth.
Swiss Patent No. 299814 discloses a bearing housing comprising a planar strip with a single continuous recessed pattern disposed therein. The strip is shaped to form a circular or semi circular sleeve which is apparently within the bearing housing for transmitting fluid according to a periodic or discrete pattern.
Other Foreign Patents which are of particular relevance to the instant invention are (FR 1029525), (DE 484148), (CH 47412) and (GB 2110314) which disclose general bearing interfaces for rotating machinery.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.
SUMMARY OF THE INVENTION
The bearing race and ring assembly according to the invention includes a bearing race having an undulating outer surface that mates with an inner surface of a mounting interface within the assembly. The mounting interface includes a plurality of rings packaged to produce inner and outer undulating mating surfaces. A viscous medium for damping bearing vibrations flows therethrough to reduce bearing vibrations within the race. The undulated surfaces are tunable to either sinusoidal or ramped relationship for viscous lubrication, forming a uniform pitch throughout. A plurality of hydraulic ball valve systems are disposed within the housing of the ring assembly for maintaining a predetermined fluid pressure.
Accordingly, it is a principal object of the invention to provide a bearing race and ring assembly which reduces bearing vibrations in rotating machinery.
It is another object of the invention to provide a bearing race and ring assembly which significantly reduces structural wear between mating surfaces in rotational machinery.
It is a further object of the invention to provide a bearing race and ring assembly which improves the relative life of bearings.
It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.
These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings.
REFERENCES:
patent: 1386255 (1921-08-01), Hindle
patent: 1965293 (1934-07-01), Jungstrom
patent: 2101346 (1937-12-01), Robertson
patent: 3513480 (1970-05-01), Robinson
patent: 4440456 (1984-04-01), Klusman
patent: 4775248 (1988-10-01), Barbic et al.
patent: 4872767 (1989-10-01), Knapp
patent: 4901014 (1990-02-01), Riegger et al.
patent: 4992024 (1991-02-01), Heydrich
patent: 5201585 (1993-04-01), Gans et al.
patent: 5205384 (1993-04-01), Heshmat
patent: 5380100 (1995-01-01), Yu
patent: 299814 (1954-09-01), None
patent: 556981 (1974-12-01), None
patent: 484148 (1926-09-01), None
patent: 1029525 (1953-06-01), None
patent: 2110314 (1983-06-01), None
patent: 1229472 (1986-05-01), None
Hannon Thomas R.
Litman Richard C.
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