Sliding Bearing and Pump Device Using the Same

Abstract

In a sliding bearing, load carrying capacity and bearing rigidity is increased without increasing a size of the bearing and the pressure of the fluid. The sliding bearing comprises a cylindrical-shaped sleeve supporting a rotatable shaft via fluid, and hydrostatic pressure pockets provided in the inner periphery of the sleeve. The hydrostatic pressure pockets constitute a plurality of rows of circumferentially disposed hydrostatic pressure pockets via orifices. At least one of the hydrostatic pressure pocket rows is arranged adjacently to each of both end portions of the inner periphery of the sleeve. And a circular cylindrical inner peripheral surface region without the hydrostatic pressure pockets is provided at a center portion of the sleeve. A width of the circular cylindrical inner peripheral surface region provided in the axial direction of the shaft is made wider than a sum of widths of the hydrostatic pressure pocket rows.

Description

CLAIM OF PRIORITY[0001]The present application claims priority from Japanese application serial No. 2011-271887 filed on Dec. 13, 2011, the content of which is hereby incorporated by reference into this applicationBACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to a sliding bearing provided with a hydrostatic pressure bearing structure in which high pressure fluid is supplied into a gap between the outer periphery of a shaft and the inner periphery of a sleeve from the outside and which supports rotational movement of the shaft, and a pump device provided with a mechanism which supports, through the sliding bearing, the rotational movement of the shaft connected to an impeller.[0004]2. Description of the Related Art[0005]As a large-sized pump device used in, for example, a circulative cooling system of a fast-breeder reactor, there has been generally used a mechanical-type vertical axial pump device in which an impeller attached to a lon...

AI Technical Summary

Benefits of technology

The sliding bearing in this invention has an improved design that allows for increased loading capability and bearing rigidity. This is achieved by supporting the rotating shaft using hydrostatic pressure from outside and dynamic pressure produced on the inner surface of the sleeve. This results in a larger pressure, making it more durable and reliable than conventional examples.

Problems solved by technology

Moreover, for the purpose of preventing the entrance of foreign material, fluid that can be used for the lubrication of the sliding bearing is limited to fluid of the same kind as the fluid to be transferred by the pump.

In the aforesaid situation, the sliding bearing itself which is used in the pump device is subjected to conditions where it is hard to obtain high dynamic pressure as compared to an oil lubricating sliding bearing used in a general mechanical device.

However, even if the phases of the hydrostatic pressure pockets are shifted in the circumferential direction and the pockets are merely arranged in the plurality of rows as described in the patent literature 1, this structure has little influence on the load carrying capacity and bearing rigidity of the bearing and it is hard for the structure to increase the load carrying capacity without increasing the pressure of an oil supplied from the outside, or without increasing the size of the bearing.

However, even if the circumferential recess grooves are provided in the annular-band portions as described in JP-A No. 57-200699, change in pressure distribution on a bearing inner periphery is small and the effects of improving the load carrying capacity and bearing rigidity of the bearing cannot be anticipated at all.

Therefore, it is hard to improve the load carrying capacity without increasing the pressure of an oil supplied from the outside or without increasing the size of the bearing.

However, in the fluid bearing device disclosed in JP-A No. 60-37329, even if the dynamic pressure that is higher than the pressure of the pressure fluid supplied from the outside is produced in the dynamic pressure generating portion, the pressure is easy to escape through the supply groove and supporting by the dynamic pressure is restricted.

Therefore, it is difficult to apply the structures disclosed in the patent literatures to the vertical-type pumps or the like.

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