Bearings – Rotary bearing – Plain bearing
Patent
1981-10-13
1984-08-21
Levy, Stuart S.
Bearings
Rotary bearing
Plain bearing
384247, 384276, 384900, F16C 2300, F16C 2302, F16C 3302, F16C 3700
Patent
active
044667523
DESCRIPTION:
BRIEF SUMMARY
The present invention concerns cylindrical ring bearings for guiding of a shaft, and more particularly, an element of such a bearing including a ring enabling effective relative centering of the bearing and the shaft, as well as centering processes for enabling such a centering.
To obtain a good alignment of two or more bearings, it is familiar to make use of bearings including oscillating rings, mounted on swivels. Such bearings tend to be complicated and expensive.
In machines of small size, generally smooth bearings are used, the position of which is adjusted by means of pins and wedges.
The alignment of such bearings is nevertheless imperfect, and there generally results asymmetric wear of the contact surfaces.
The present invention has as an object the provision of a new and improved centering ring bearing construction and process to obtain perfect relative centering of the shaft and a bearing without the occurrence of the disadvantages cited above.
Other and further objects will be explained hereinafter and are delineated in the appended claims.
In summary, according to the invention, each bearing element includes a centering ring consisting of a material the thermal expansion coefficient of which is greater than that of the shaft, positioned essentially coaxially to the shaft at the interior of the bearing, with an amount of play such that with appropriate cooling, the ring contracts onto the shaft. According to a preferred mode of realization, the ring is placed in the immediate proximity of the journal at the interior of the bearing element, and its internal diameter at ambient temperature is very sightly greater than that of the journal.
The material constituting the ring is, preferably, a polytetrafluoroethylene, whose thermal expansion coefficient is more than ten times greater than that of the steel making up the shaft.
However, other materials, such as polyethylene, certain polyamides and vinylidene polyfluoride, may be equally favorably used.
With such a bearing, the process of relative centering of the shaft and the bearing is extremely simplified. It consists of the following successive steps: contraction; C.
The invention will be better understood, and other goals, advantages and characteristics will be made clearer through the following description, referencing the accompanying drawing.
The single FIGURE represents an axial section through a bearing element conforming to one of the preferred or best modes of realization of the invention.
In this FIGURE, the shaft 1 is vertical. The bearing element includes a housing 2 defining a circumferential groove therein within which are placed a journal 3 and a ring 4, with an appropriate play with respect to the shaft 1. As shown, the shaft extends through apertures at opposite ends of the housing.
The bearing generally consists of a number of juxtaposed elements conforming to the element represented in the FIGURE. The thermal expansion coefficient of the material selected for constituting this ring 4 is very much greater than that of the material constituting the shaft.
For example, with a shaft of carbon steel whose thermal expansion coefficient is in the neighborhood of 11.times.10.sup.-6 .degree. C.sup.-1 and a graphite journal whose thermal expansion coefficient is essentially equal to that of carbon steel, the ring may favorably be constituted by polytetrafluoroethylene, whose expansion coefficient is in the neighborhood of 130.times.10.sup.-6 .degree. C.sup.-1.
According to the mode of realization represented, the ring 4 is placed in the immediate proximity of the journal 3 within the housing 2 of the bearing, and its internal diameter at ambient temperature is very slightly greater than that of the journal 3.
According to one example, the diameter of the shaft being 60.0 mm, the internal diameter of the journal is equal to 60.2 mm, while the internal diameter of the ring is equal to 60.3 mm at ambient temperature.
For this reason, in normal functioning, there is no contact between the ring 4 and the shaft 1, the ring 4 acting exclusively a
REFERENCES:
patent: 1963940 (1934-06-01), Duffy
patent: 2774704 (1956-12-01), Smith
patent: 2981573 (1956-06-01), Reuter
patent: 3363300 (1964-10-01), Stec
patent: 3774983 (1973-11-01), Lagally
patent: 4181322 (1980-01-01), Kroniger
Hannon Thomas R.
Jeumont-Schneider
Levy Stuart S.
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