JP4614524B2 - Electric corrosion prevention device for underwater rotating machine - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electric corrosion prevention device for an underwater rotating machine such as an underwater electric pump and an aeration / stirring device.
[0002]
[Prior art and its problems]
In an underwater rotating machine such as an underwater electric pump or an aeration / stirring device, corrosion is particularly likely to occur in the vicinity of a liquid contact portion or a gap between a rotating body portion and a stationary body portion. It has already been elucidated that the cause of corrosion is due to the action of the corrosion cell formed on the metal surface. If the potential difference between the anode and cathode of the corrosion cell can be eliminated, the corrosion current flows. The corrosion will stop after it disappears.
[0003]
However, the rotating shaft of the submersible rotating machine, such as an underwater electric pump and aeration / stirring device, is supported by a bearing such as a ball bearing, and the gap between the opposing surfaces of the inner and outer rings of the bearing is filled with lubricating grease. Since the grease is non-conductive, an insulating oil film is formed at the contact portion between the inner and outer rings and the ball when the rotating shaft rotates, and the bearing inner ring and the rotating body part connected to it, the bearing outer ring and the stationary body part connected to it are It is inevitable that a completely insulated state is caused and corrosion is caused by a potential difference.
[0004]
Various coatings and coatings have also been tried as a measure to protect against corrosion, but coating and coating on rotating parts can be easily peeled off due to wear and cavitation, and even partially. Even if it peels, once it peels, the electrolytic corrosion prevention function will be lost and corrosion will advance. In addition, an electrical corrosion prevention method that attempts to obtain an anticorrosion effect by sacrificial dissolution of the anode material has also been attempted, but this requires that the entire mechanical structure be in an electrically conductive state, and even part of it is non-conductive. In the normal state, there is no effect, and the biggest bottleneck is that the rotating body portion and the stationary body portion are divided by the bearing portion when the motor is driven as described above.
[0005]
OBJECT OF THE INVENTION
The object of the present invention is to reduce the potential difference generated between the rotating body part and the stationary body part when the prime mover is driven without requiring painting or expensive coating on the rotating part, etc. An object of the present invention is to provide an electric corrosion prevention device for an underwater rotating machine.
[0006]
[Structure of the invention]
In the electrolytic corrosion preventing device for an underwater rotating machine according to the present invention, an annular seat portion that contacts the end face of the bearing outer ring is bent into a wave washer shape, and is led from the inside of the annular seat portion to be near the end face center portion of the rotating shaft. The ring-shaped seat is overlapped on the end surface of the bearing outer ring fitted to the bearing housing using the elastic conductor having a contact piece in contact with the bearing housing, and near the end surface center portion of the rotating shaft fitted to the bearing inner ring. The surface of the annular seat portion is pressed by the cover-like wall of the bearing housing in a state in which the rotating shaft is in contact with each other, so that the rotating shaft and the rotating body portion connected thereto are electrically connected to the bearing housing and the stationary body portion connected thereto. It was comprised so that it might be conducted to.
[0007]
【Example】
In the following, an explanation will be given using a case where the submersible electric pump is an implementation target.
[0008]
In FIG. 1, reference numeral 1 denotes a motor rotation shaft, and an impeller 3 is attached to the load side outlet end. Reference numeral 4 denotes a bearing that supports the non-load-side lead-out end of the rotating shaft 1, and a bearing inner ring 4 a that is stationary on the rotating shaft 1 and a bearing that is stationary on the bearing housing 5 as shown in detail in FIGS. 2 and 3. The outer ring 4b faces the ball 4c. Reference numeral 6 denotes an elastic conductor made of spring steel or the like. An annular seat portion 6a that is bent into a wave washer shape and overlaps with an end face of the bearing outer ring 4b, and is guided from the inside of the annular seat portion 6a to rotate. The contact piece 6b is bent so as to be in contact with the vicinity of the end surface center portion of the shaft 1. In the embodiment of FIGS. 4 and 5 as a concrete extending form of the contact piece 6b, a single contact piece 6b is led out from one place inside the annular seat portion 6a toward the center. However, it is not necessarily limited to this extended form, and a plurality of contact pieces are led out centripetally from several locations inside the annular seat 6a, or in the diametrical direction so that both ends are connected to the inside of the annular seat 6a. It may be a touch piece in an installed state.
[0009]
Then, the annular seat 6a of the elastic conductor 6 is superposed on the end face of the bearing outer ring 4b fitted to the bearing housing 5, and elastic conduction is conducted to the end face center part of the rotating shaft 1 fitted to the bearing inner ring 4a or its peripheral part. By contacting the contact piece 6b of the body 6 and pressing the surface of the wave washer with the lid-like wall 8 of the bearing housing 5, the annular seat 6a of the elastic conductor 6 is fixed in pressure contact with the end face of the bearing outer ring 4b. The contact piece 6b elastically contacts the vicinity of the center of the end surface of the rotary shaft 1, and the rotary shaft 1 and the bearing outer ring 4b are electrically connected via the elastic conductor 6, and eventually the rotary shaft 1 In addition, the rotating body portion such as the impeller 3 connected to the bearing housing 5 and the stationary body portion such as the motor outer body 10 and the head cover 11 connected to the bearing housing 5 are electrically connected to each other. Reference numeral 12 denotes a galvanic anode made of a low potential metal such as an aluminum alloy, and is attached to an outer liquid contact portion of a stationary body portion such as the head cover 11, for example.
[0010]
[Action]
By electrically connecting the rotating shaft and the bearing housing with the elastic conductor in the above-described form, the rotating shaft and the rotating body portion connected to the rotating shaft, and the bearing housing and the stationary body portion connected to the rotating shaft when the underwater rotating machine is driven. And the corrosion current cannot flow, and the flow of the anticorrosion current due to the elution of the galvanic anode is formed, resulting in an anticorrosive action.
[0011]
【The invention's effect】
According to the device of the present invention, the submersible rotating machine such as the submersible electric pump and the aeration / stirring device can be applied to the rotating body portion and the stationary body portion when the prime mover is driven without requiring painting or expensive coating on the rotating portion. By reducing the potential difference that occurs, a permanent and low-cost electric corrosion prevention effect can be obtained.
[Brief description of the drawings]
FIG. 1 is a longitudinal side view of a submersible electric pump to which a device of the present invention is applied.
FIG. 2 shows an example in which the bearing housing and its lid-like wall have a structure that can be divided, which is a longitudinal side surface of the main part of the device of the present invention.
FIG. 3 is a longitudinal side view of a main part of the device of the present invention, showing an example in which a bearing housing and its lid-like wall are integrated.
FIG. 4 is a plan view of an elastic conductor in the device of the present invention.
5 is a longitudinal side view taken along line AA in FIG. 4. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Rotating shaft 4a Bearing inner ring | wheel 4b Bearing outer ring | wheel 5 Bearing housing 6 Elastic conductor 6a Annular seat part 6b Contact piece 8 Cover-like wall of a bearing housing

Claims (1)

An annular seat (6a) in contact with the end face of the bearing outer ring (4b) is bent into a wave washer shape, is led from the inside of the annular seat (6a), and is in contact with the vicinity of the end face center of the rotating shaft (1). Using the elastic conductor (6) having the contact piece (6b), the annular seat (6a) is superposed on the end surface of the bearing outer ring (4b) fitted to the bearing housing (5) and the bearing inner ring (4a). In the state where the contact piece (6b) is brought into contact with the vicinity of the end surface center portion of the rotating shaft (1) fitted to the surface of the annular seat portion (6a), the surface of the annular seat portion (6a) is covered with a lid-like wall ( 8), the rotating shaft (1) and the rotating body portion connected to the rotating shaft are electrically connected to the bearing housing (5) and the stationary body portion connected thereto. Electric corrosion prevention device for underwater rotating machines.

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