JP6242566B2 - Electric corrosion prevention device - Google Patents

Description

  The present invention includes a rotary shaft that is rotated by an electric motor, a bearing that rotatably supports the rotary shaft, a static elimination member that is electrically connected to the rotary shaft, and a ground wire that grounds the static elimination member. The present invention also relates to an electrolytic corrosion prevention device for preventing a bearing from electrolytic corrosion by removing electric charges charged on a rotating shaft.

  For example, in a rotating machine equipped with a rotating shaft that is rotated by an electric motor such as a turbo refrigerator, the rotating shaft is rarely charged, and the charged electric charge flows as a current to a bearing that supports the rotating shaft. There was a case where electric corrosion occurred. As a technique for preventing the electric corrosion of such a bearing, for example, Patent Document 1 discloses a technique for preventing the electric corrosion of the bearing by insulating the rotating shaft and the bearing by, for example, forming a rolling element constituting the rolling bearing with ceramics. Is disclosed.

  However, the rolling bearing of Patent Document 1 described above has a problem that the rolling elements are made of ceramics and are expensive. As a configuration for preventing electrolytic corrosion of a bearing formed of a conductive material, such as a rolling bearing made of a normal steel rolling element, for example, an electrolytic corrosion prevention device as shown in FIG. 6 can be considered.

  6 includes a rotating shaft 103 of an electric motor 102 and bearings 106a and 106b that rotatably support the rotating shaft 103, and an outer peripheral surface 103a of the motor rotating shaft 103. A neutralizing member 112 that abuts and a ground wire 114 that grounds the neutralizing member 112 are provided. Then, the rotating shaft 103 is grounded by the ground wire 114 through the static elimination member 112, thereby removing the electric charge charged in the rotating shaft 103 and preventing the bearings 106a and 106b from being electrolytically corroded. In the figure, reference numeral 108 denotes a rotating body such as a blade, reference numeral 104 denotes a shaft coupling that connects the shaft 110 of the rotating body 8 and the rotating shaft 103 of the electric motor 102, and reference numeral 116 denotes a static elimination member 112. An urging mechanism such as an urging spring that urges and contacts the outer peripheral surface 103 a of the rotating shaft 103.

JP 2007-16846 A Japanese Patent No. 4562271

  However, in the electric corrosion prevention apparatus 100 described above, there is a possibility that the lubricating oil reaches the static elimination member 112 through the rotary shaft 103 and the contact portion between the rotary shaft 103 and the static elimination member 112 is in a fluid lubrication state. is there. Thus, when the contact portion between the rotating shaft 103 and the charge removal member 112 is in a fluid lubrication state, no current flows between them, and the electric charge charged on the rotating shaft 103 cannot be removed by the ground wire 114. .

  In order to prevent the contact portion between the rotary shaft 103 and the static elimination member 112 from entering a fluid lubrication state, it is considered effective to bring the static elimination member 112 into contact with the tip surface 103b of the rotary shaft 103. Oil intrusion into the contact portion is more likely to occur as the sliding speed between the rotation shaft 103 and the charge removal member 112 increases. Therefore, the charge removal member 112 is brought into contact with the tip surface 103b of the rotation shaft 103 instead of the outer periphery 103a. This is because the sliding speed between the rotating shaft 103 and the charge removal member 112 can be reduced.

  Patent Document 2 discloses a galvanic corrosion prevention device that makes a charge removal member contact the tip surface of a rotation shaft and removes electric charges charged on the rotation shaft from the charge removal member. However, in the electric corrosion prevention device of Patent Document 2, the static elimination member and the tip surface of the rotating shaft are in direct line contact, and the tip surface of the rotating shaft is worn, so the rotating shaft is periodically replaced. There is a problem that needs to be done.

  The present invention has been made in view of the above-described problems of the prior art, and it is an object of the present invention to provide an electrolytic corrosion prevention device that can prevent wear of a rotating shaft by a charge removal member and that does not require replacement of the rotating shaft. Yes.

The present invention is an invention made to achieve the above-described object,
The electric corrosion prevention device of the present invention is
An electroerosion comprising: a rotary shaft that is rotated by an electric motor; a bearing that rotatably supports the rotary shaft; a static elimination member that is electrically connected to the rotary shaft; and a ground wire that grounds the static elimination member. In the prevention device,
The neutralizing member is electrically connected to the rotating shaft through a conductor coupled to a tip surface of the rotating shaft.

  Thus, the electric corrosion prevention apparatus of the present invention is configured to electrically connect the static elimination member and the rotary shaft via the conductor coupled to the tip surface of the rotary shaft, and the rotary shaft and the static elimination member are connected to each other. Because it does not contact directly, the tip surface of the rotating shaft does not wear. Further, even if the conductor is worn, it is not necessary to replace the rotating shaft because only the conductor needs to be replaced.

  In addition, since the static elimination member and the rotating shaft are electrically connected via the conductor, the material of the conductor can be different from the material of the rotating shaft. For example, it is possible to suppress wear of the conductor itself by adopting a high-hardness material that does not easily wear to the conductor.

  In addition, it is easier to finish the surface with respect to the conductor as compared with the case where the surface finish is performed on the end surface of the rotating shaft, which is a long rod-shaped member. Therefore, by using a conductor having a small surface roughness, it is possible to suppress wear of the neutralizing member that is the counterpart.

In the above invention,
It is desirable that the conductor is configured to be in point contact with the charge removal member at a rotation center position of the conductor that rotates together with the rotation shaft.

  In this way, if the static elimination member is configured to make point contact with the rotation center position of the conductor, the sliding speed at the rotation center position is 0, so that there is almost no wear at the contact portion between the static elimination member and the conductor. Does not occur.

  At this time, the conductor has a spherical shape and is joined to the tip surface of the rotating shaft by any method of welding, brazing, or bonding, so that the conductor is in point contact with the static elimination member at the rotation center position. The above invention can be easily configured. As such a spherical conductor, a rolling ball for a rolling bearing having high hardness, high dimensional accuracy, and low surface roughness can be suitably used.

In the above invention,
The conductor may be a bolt member that is coupled to the rotating shaft by being screwed into a screw hole formed in a central portion of the tip surface of the rotating shaft.

  As described above, when the conductor is a bolt member and the conductor and the tip end surface of the rotating shaft are connected by screwing, the conductor can be easily replaced when worn. At this time, the head of the bolt member that comes into contact with the charge removal member is processed into a spherical shape, so that the conductor can be in point contact with the charge removal member at the rotation center position.

In the above invention,
Desirably, oil draining means is provided between the tip surface of the rotating shaft and a bearing adjacent to the tip surface so as to protrude from the outer peripheral surface of the rotating shaft.

  If such oil draining means is formed, it is possible to prevent the lubricating oil from reaching the charge removal member along the rotating shaft.

  According to the present invention, since the static elimination member and the rotary shaft are configured to be electrically connected via the conductor coupled to the tip surface of the rotary shaft, it is possible to prevent the rotary shaft from being worn by the static elimination member. It is possible to provide an electrolytic corrosion prevention device that does not require the rotation shaft to be replaced.

It is the whole figure which showed the whole structure of the electric corrosion prevention apparatus of this invention. It is the schematic side view which showed the conductor of this invention. It is the schematic side view which showed the conductor of another embodiment of this invention. It is the schematic side view which showed the oil draining means of this invention. It is the schematic side view which showed another embodiment of the oil draining means of this invention. It is the whole figure which showed the whole structure of the conventional electric corrosion prevention apparatus.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
However, the scope of the present invention is not limited to the following embodiments. The dimensions, materials, shapes, relative arrangements, and the like of the components described in the following embodiments are merely illustrative examples and are not intended to limit the scope of the present invention only unless otherwise specified.

  FIG. 1 is an overall view showing the overall configuration of the electrolytic corrosion prevention device of the present invention. The electric corrosion prevention apparatus of the present invention is an apparatus provided in a rotating machine including a rotating shaft that is rotated by an electric motor such as a turbo refrigerator. As shown in FIG. 1, the electrolytic corrosion preventing device of the present invention includes a rotating shaft 3, bearings 6 a and 6 b, a static eliminating member 12, a ground wire 14, and a conductor 20.

  The rotating shaft 3 is a long rod-shaped member formed of a conductive material such as metal. The rotating shaft 3 has a base end connected to a shaft 10 via a shaft coupling 4 and is configured to rotate by the electric motor 2. In addition, a rotating body 8 such as a blade is fixed to the outer peripheral surface 10 a of the shaft 10.

  The bearings 6a and 6b are, for example, rolling bearings in which rolling elements such as balls and rollers are disposed between the shaft and the raceway, and support the rotating shaft 3 described above in a rotatable manner. The bearings 6a and 6b are formed of a conductive material such as a metal, and a lubricating oil for enhancing lubricity is enclosed therein. In addition, a slide bearing, a fluid bearing, etc. are employable as a bearing of this invention, It is not limited to a rolling bearing.

  The static elimination member 12 is a columnar member made of a conductive material such as carbon or copper, and is electrically connected to the above-described distal end surface 3b of the rotary shaft 3 via a conductor 20 described later. . In addition, a ground wire 14 is connected to the static elimination member 12, and the static elimination member 12 is grounded by the ground wire 14. Further, the charge removal member 12 is biased toward the conductor 20 described later by a biasing mechanism including a biasing spring 16 or the like, for example.

  Moreover, between the front end surface 3b of the rotating shaft 3, and the bearing 6b, the oil draining means 30 mentioned later protrudes from the outer peripheral surface 3a. When there are a plurality of bearings, the oil draining means 30 is formed between the bearing 6b and the tip surface 3b that are closest to the tip surface 3b (adjacent to the tip surface 3b).

  The conductor 20 is a member that is formed of a conductive material such as metal and is configured separately from the rotating shaft 3 and the charge removal member 12, and is coupled to the central portion of the tip surface 3 b of the rotating shaft 3. . The conductor 20 is, for example, a metal sphere 20a as shown in FIG. 2, and is welded, brazed, or the like, for example, to the joint recess 3c formed at the center of the tip surface 3b of the rotating shaft 3. They are joined by a method such as adhesion. It is possible to join the spherical body 20a to the tip surface 3b in which the joining concave portion 10c is not formed. Generally, however, the center of the tip surface 3b of the rotating shaft 3 is used for conveying and positioning the rotating shaft 3. It is good to use this recessed part as the recessed part 3c for joining.

  The electric corrosion prevention apparatus 1 of the present invention configured as described above has a configuration in which the charge removal member 12 and the rotary shaft 3 are electrically connected via the conductor 20 coupled to the distal end surface 3b of the rotary shaft 3. Yes, the rotating shaft 3 and the charge removal member 12 are not in direct contact. For this reason, even if the rotating shaft 10 rotates, the front end surface 3b of the rotating shaft 3 is not worn. Further, even if the conductor 20 is worn, it is only necessary to replace the conductor 20, and there is no need to replace the rotating shaft 3.

  Further, since the static elimination member 12 and the rotary shaft 3 are electrically connected via the conductor 20, the material of the conductor 20 can be made different from the material of the rotary shaft 3. For example, it is possible to suppress wear of the conductor itself by adopting a high hardness material such as carbon steel which is hard to be worn as the conductor 20.

  Moreover, compared with performing surface finishing on the front end surface 3b of the rotating shaft 3 which is a long rod-shaped member, it is easier to perform surface finishing on the conductor 20. Therefore, by using the conductor 20 having a small surface roughness, it is possible to suppress wear of the neutralizing member 12 that is the counterpart.

  Further, by using the sphere 20a as shown in FIG. 2 as the conductor 20, at the rotational center position a of the conductor 20 (sphere 20a) that rotates with the rotating shaft 3, the static elimination member 12 and the conductor 20 (sphere 20a). ) And point contact. Thus, if the conductor 20 is configured to make point contact with the static elimination member 12 at the rotation center position a, the sliding speed at the rotation center position a is 0. It is possible to prevent almost any wear from occurring at the contact portion. Moreover, as such a spherical conductor 20, a rolling ball for a rolling bearing having high hardness, high dimensional accuracy, and low surface roughness can be suitably used.

  Further, as the conductor 20, a metal bolt member 20b as shown in FIG. 3 may be employed. The bolt member 20b is coupled to the tip surface 3b by screwing the shaft portion 22b into a screw hole 10d formed at the center of the tip surface 3b of the rotary shaft 10. Further, in a state where the bolt member 20b and the tip surface 10b are connected, the head 24b of the bolt member 20b protruding from the tip surface 3b and the charge removal member 12 come into contact with each other, so that the rotary shaft 3 and the charge removal member 12 are electrically connected. Connected.

  In this way, when the conductor 20 (bolt member 20b) is worn by using the conductor 20 as a bolt member 20b and connecting the bolt member 20b and the tip surface 3b of the rotary shaft 3 by screwing. The replacement can be easily performed. At this time, the head 24b of the bolt member 20b that contacts the static eliminating member 12 is processed into a spherical shape, so that the static eliminating member 12 can be configured to make point contact with the rotational center position a of the bolt member 20b.

  Further, as shown in FIG. 1, in the electrolytic corrosion prevention device 1 of the present invention, an oil draining means 30 is formed between the tip surface 3b and the bearing 6b so as to protrude from the outer peripheral surface 3a of the rotary shaft 3. ing. As this oil draining means 30, for example, as shown in FIG. 4, an annular plate-like member 30a that is fitted and fixed to the outer peripheral surface 3a of the rotating shaft 3 can be cited. In addition, for example, a step portion 30b integrally formed on the outer peripheral surface 3a of the rotating shaft 3 as shown in FIG. 5 is also included.

  If such oil draining means 30 is formed, the lubricating oil that leaks from the bearing 6b and reaches the plate-like member 30a and the stepped portion 30b through the rotating shaft 3 is indicated by an arrow f in the figure. Then, after flowing in the outer peripheral direction, it is scattered by centrifugal force. That is, if such oil draining means 30 is formed, it is possible to prevent the lubricating oil from reaching the static elimination member 12 through the rotary shaft 3, and the contact portion between the rotary shaft 3 and the static elimination member 12 is prevented. It is possible to reliably prevent the current from flowing between the two due to the fluid lubrication state.

  As mentioned above, although the preferable form of this invention was demonstrated, this invention is not limited to said form, A various change in the range which does not deviate from the objective of this invention is possible.

  INDUSTRIAL APPLICABILITY The present invention can be suitably used as a galvanic corrosion prevention device that can prevent galvanic corrosion of a bearing in a rotary machine that includes a rotating shaft that is rotated by an electric motor such as a turbo refrigerator.

DESCRIPTION OF SYMBOLS 1 Electric corrosion prevention apparatus 2 Electric motor 3 Rotating shaft 3a Outer peripheral surface 3b Front end surface 3c Connection recessed part 3d Screw hole 4 Shaft coupling 6a, 6b Bearing 8 To-be-rotated body 10 Shaft 12 Static elimination member 14 Lead wire 16 Energizing spring Force mechanism)
20 Conductor 20a Sphere 20b Bolt member 30 Oil draining means 30a Plate member 30b Stepped portion

Claims (3)

A rotating shaft arranged along a horizontal direction that is rotated by an electric motor;
A bearing that rotatably supports the rotating shaft;
A conductor joined to the tip surface of the rotating shaft and configured separately from the rotating shaft;
A static elimination member electrically connected to the rotating shaft via the conductor;
An earth wire for grounding the static elimination member;
A biasing spring that biases the static elimination member toward the conductor,
The conductor has a spherical shape, and is welded, brazed, or bonded to a conical recess formed on a tip surface of the rotating shaft,
The static elimination member has a cylindrical shape, one end surface is in contact with the conductor, the other end surface is in contact with the biasing spring, and a peripheral surface is in contact with the ground wire ,
The electrolytic corrosion prevention device according to claim 1, wherein the static elimination member is located on a side farther from the rotary shaft in the axial direction of the rotary shaft than the tip surface of the rotary shaft .   2. The electrolytic corrosion prevention device according to claim 1, wherein the electrical conductor is configured to make point contact with the static elimination member at a rotational center position of the electrical conductor that rotates together with the rotational shaft.   The oil draining means which protrudes from the outer peripheral surface of a rotating shaft is formed between the front end surface of the said rotating shaft, and the bearing adjacent to this front end surface, The Claim 1 or 2 characterized by the above-mentioned. Electric corrosion prevention device.

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