JP2001140910A - Bearing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bearing device reducing a potential difference caused between a rotor portion and a stator portion during the drive of an underwater rotary machine, and having a permanent and effective function to prevent electrolytic corrosion without increasing a coefficient of friction. SOLUTION: A bearing cover 10b is fitted over the outside of a bearing bracket 6 into which a bearing outer ring 7 is stationarily fitted, and a gap portion 9b formed between the axial end of a rotating shaft 1 around which a bearing inner ring 5 is stationarily fitted and the inner surface of the bearing cover 10b is filled with conductive grease 11 to electrically connect the bearing cover 10b to the rotating shaft 1. A grease replenishment means 14 extending to the gap portion 9b from the outside of the bearing cover 10b is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing device used for supporting a rotating shaft of a submersible rotating machine, such as a submersible electric pump and an aeration / stirring device.

[0002]

2. Description of the Related Art Underwater rotating machines, such as underwater electric pumps and aeration / stirring devices, are particularly susceptible to corrosion in the vicinity of a liquid-contacting part or a gap between a rotating part and a stationary part.
It has already been clarified that the cause of the corrosion is due to the action of the corrosion battery formed on the metal surface, and if the potential difference between the anode and cathode of the corrosion battery could be eliminated, corrosion current would flow. It will disappear and the corrosion will stop.

However, the rotating shaft of a submersible rotating machine such as a submersible electric pump or an aeration / stirring device is supported by a bearing, and the inner ring and the outer ring of the bearing are in contact with each other via a ball almost in a point contact manner. The gap between the opposing surfaces of the inner and outer rings is filled with lubricating grease, and the grease is non-conductive. An insulating oil film is formed on the bearing, and the bearing inner ring and the rotating body part connected thereto are completely insulated from the bearing outer ring and the stationary body part connected thereto, and it is inevitable that corrosion occurs due to the potential difference.

As means for electrically connecting the inner and outer rings of the bearing, it has been attempted to slide a metal spring plate derived from the inner peripheral portion of the outer ring against the outer peripheral surface of the inner ring. The coefficient increases, the power loss increases, and
The spring plate is also extremely worn and poor in durability, and cannot be practically used at all.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to reduce a potential difference between a rotating body portion and a stationary body portion when a submersible rotating machine is driven,
It is another object of the present invention to provide a bearing device having a permanent and effective electrolytic corrosion prevention function without increasing a wear coefficient.

[0006]

In the bearing device according to the present invention, a bearing cover is covered from the outside of a bearing bracket to which a bearing outer ring is fitted, and a shaft end of a rotary shaft to which a bearing inner ring is fitted and the bearing cover. A gap formed between the inner surface and the inner surface is filled with conductive grease to electrically connect the bearing cover and the rotating shaft, and grease replenishing means is provided from the outside of the bearing cover to the gap. .

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A case in which the present invention is used for a rotary shaft of a submersible pump will be described below.

In FIG. 2, reference numeral 1 denotes a rotating shaft fitted to a motor rotor 2, and an impeller 3
Is installed. Numeral 4A denotes a bearing on the non-load side of the rotating shaft 1, which includes a bearing inner ring 5 which fits on the rotating shaft 1 and a bearing outer ring 7 which fits on the bearing bracket 6, as shown in detail in FIG.
Are opposed to each other with the ball 8 interposed therebetween. 10b is superimposed on the center of the bearing bracket 6 and
A bearing cover 10b is filled with conductive grease 11 in a gap 9b formed between the inner surface of the bearing cover 10b and the end surface of the rotating shaft 1 on the non-load side. In addition, the bearing bracket 6 and the rotating shaft 1 are electrically connected to each other, so that the rotating body such as the rotor 2 and the impeller 3 connected to the rotating shaft 1 and the motor outer shell 1 connected to the bearing bracket 6 are extended.
2 and the stationary body portion such as the head cover 13 are electrically connected. Reference numeral 14 denotes a grease replenishing means provided so as to communicate with the gap 9b from the outside of the bearing cover 10b. The grease replenishing means may be a grease cup type as shown in the drawing, or a grease injection pipe type led out onto the head cover 10b. Good. Reference numeral 16 denotes a galvanic anode made of a metal having a low potential, such as an aluminum alloy, and is attached to a liquid-contact part such as the head cover 13.

[0009]

Since the rotating body portion and the stationary body portion can be electrically connected as described above, the potential difference between the two portions during driving is reduced, so that the corrosion current stops flowing and the current-carrying anode is removed. A current of the anticorrosion current is formed by the elution, and an anticorrosion action is produced.

[0010]

By using the bearing device of the present invention, the potential difference generated between the rotating body and the stationary body when the underwater rotary machine is driven is reduced, and permanent and effective electrolytic corrosion is performed without increasing the wear coefficient. The prevention function will be provided.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view of a bearing device of the present invention.

FIG. 2 is a vertical sectional side view of a submersible electric pump using the bearing device of the present invention.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 rotating shaft 5 bearing inner ring 6 bearing bracket 7 bearing outer ring 9b void between shaft end of rotating shaft and bearing cover inner surface 10b bearing cover 11 conductive grease 14 grease replenishing means

Claims (1)

[Claims] 1. A gap formed between a shaft end of a rotating shaft, on which a bearing inner ring is fitted, and a bearing cover, which is covered from the outside of the bearing bracket with which the bearing outer ring is fitted, and an inner surface of the bearing cover. The part is filled with conductive grease to electrically connect the bearing cover and the rotating shaft,
And a grease replenishing means connected to the gap from outside the bearing cover.