Bearings – Rotary bearing – Fluid bearing
Patent
1984-05-01
1985-12-10
Levy, Stuart S.
Bearings
Rotary bearing
Fluid bearing
384113, F16C 1710
Patent
active
045576106
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to a dynamic pressure type fluid bearing device, and is to present a dynamic pressure type fluid bearing device which is usable under both high pressure and low pressure, can be manufactured by a simple process, and is low in cost.
DESCRIPTION OF THE PRIOR ART
In a conventional dynamic pressure type fluid bearing device (hereinafter briefly called a fluid bearing device), as shown in FIGS. 1 and 2, a bearing hole 1a is provided at high precision in a housing 1, and a thrust bearing member 2 is fitted at a right angle to the hole in the lower part of the housing, and a shaft 3 is rotatably provided in the hole 1a in the housing 1. Grooves 3d are processed in the shaft 3 by etching or other process, and are filled with an oil or grease lubricant 4a. On the other hand, in the top of the thrust bearing member 2 on the confronting side, grooves 2a as shown in FIG. 2 are formed, and the grooves 2a, 3d are filled with lubricants 4a and 4b and thereby constituting a fluid bearing in the radial and thrust directions. Air or other gas 5 is left over inside the bearing enclosed at this time. In this state, when the shaft 3 or housing 1 is rotated by a motor (not shown), a pressure is built up by the pumping action of the grooves 2a and 3d, so that the rotation is effected without contact.
With this construction, however, when the bearing device is used in a state of low pressure, such as on the top of a high mountain and in the outer space, the gas 5 expands under reduced pressure, and the lubricant 4a in the radial groove 1a is forced out upward. What is more, when this conventional bearing device is being used in a horizontal position, the lubricant 4a flows out of the bearing unit, and a lubricant shortage occurs in the bearing, which may give rise to seizure. Similarly, when this bearing is used under high pressure, the gas 5 contracts at elevated pressure, and the lubricant 4a in the radial bearing is pushed in downward, and a lubricant shortage occurs in the radial groove 3d, which may also give rise to seizure. These defects at low or high pressure may occur, if the enclosed bearing is uniformly filled with lubricant without any gas 5, as far as tiny air bubbles are contained in the lubricants 4a and 4b. For instance, air bubbles in the lubricant 4b may expand under reduced pressure to force out the lubricant 4a from the radial bearing.
DISCLOSURE OF THE INVENTION
The present invention provides the advantage of being usable under both high pressure and low pressure by comprising a housing having a bearing hole, a shaft rotatably provided in the bearing hole, grooves for building up a force in the radial direction provided in the shaft or housing, a thrust bearing member having grooves to build up a force in the thrust direction attached to the end of the shaft, shallow ventilation flutes provided in the junction plane against the housing of this thrust bearing member, and lubricants charged into both grooves.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view of a conventional fluid bearing device,
FIG. 2 describes the groove profile of the thrust bearing unit of the same,
FIG. 3 is a sectional view of a fluid bearing device according to one of the embodiments of the present invention,
FIG. 4 is a magnified sectional view of an important part of the same device,
FIG. 5 is a plan view of the thrust bearing member of the same,
FIG. 6 is a plan view of a modified example of the same thrust bearing member,
FIG. 7 is a magnified sectional view of an important part of a second embodiment, and
FIG. 8 is a magnified view of a thin plate of the same.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
One of the embodiments of the present invention is described below with reference to FIGS. 3 to 6. In these drawings, numeral 11 denotes a housing, in which is provided a hole 11a serving as a bearing, and a shaft 13, in which are provided grooves 13c and 13d for radial fluid bearing by etching or other process, is rotatably provided in hole 11a. A lower end plane
REFERENCES:
patent: 3718379 (1973-02-01), Williams et al.
patent: 3758177 (1973-09-01), Williams
Asada Takafumi
Matsumoto Hideo
Onishi Toshio
Senma Kajuyoshi
Levy Stuart S.
Matsushita Electric - Industrial Co., Ltd.
Werner David
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