JP2006087225A - Electric corrosion preventing device of motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric corrosion preventing device of a motor that is low in price, free of maintenance and can easily avoid a harmonic voltage and a current generated at a movable element. <P>SOLUTION: The motor comprises an armature 4 wound with a driving winding 3, a magnetic filed 10 formed by installing a plurality of magnets 9 to a rotor 8 composed of a laminated core, and a bearing 11. The motor also comprises a primary coil 12 that is arranged on the side of the armature 4 that constitutes a stator, and wound to a first ferrite core 15; and a secondary coil 13 that is arranged at the rotor 8 of the magnetic field 10 via the primary coil 12 and a clearance, and wound to a second ferrite core 16. The primary coil 12 is connected between the neutral point of the Y-connection of the driving winding 3 at the armature 4 and a frame 1, and a resistor 14 is connected to the secondary coil 13 arranged at the rotor 8 side. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rotary electric motor or a direct acting electric motor driven by an inverter device, a servo drive device or the like, and more particularly to an electric corrosion prevention device for a motor that prevents electric corrosion of a bearing due to electric charges generated in a mover of the electric motor.

Conventionally, a rotary electric motor driven by an inverter device or a servo drive device as a drive source of equipment is as shown in FIG. FIG. 4 will be described using an example of a synchronous motor using a surface magnet type rotor.
FIG. 4 is a side sectional view of an electric motor showing a conventional example.
In FIG. 4, 1 is a frame, 2 is an armature core made of a laminated core, 3 is a driving winding inserted in a slot portion of the armature core 2, and 4 is composed of an armature core 2 and a winding 3. Armatures 5 and 6 are brackets fixed to the load side and the anti-load side of the frame 1, 7 is a rotating shaft, 8 is a rotor made of a laminated iron core fitted to the outer periphery of the rotating shaft 7, and 9 is an armature 4 Permanent magnets provided through a gap and provided on the surface of the rotor 8, 10 is a field that forms the secondary side with the rotor 8 and the permanent magnet 9, and 11 rotates the rotary shaft 7 through the brackets 5 and 6. It is a rolling bearing that is supported freely. The electric motor relatively rotates with one field as a mover and the other armature as a stator (see, for example, Patent Document 1).

However, in the above configuration, when the electric motor is driven by the inverter device, the mover by the inverter device is in an electrically floating state with respect to the stator, so that charges are generated in the rotor due to the harmonics and the capacitance. The electric charge accumulated in the rotor is transmitted to the rotating shaft, and flows as an axial current to the bracket side via the rolling bearing which is a support point of the rotating shaft. This is because the shaft current flows by causing a discharge (spark) through the lubricant in the part of the bearing ball (rolling element) in contact with the bracket, and this discharge causes the rolling element and inner and outer rings of the rolling bearing to flow. Eroded the raceway surface. Furthermore, when the electric corrosion progresses, abnormal noise may be generated in the rolling bearing, or the rolling bearing may be seized or melted.
For this reason, as a measure to avoid electrolytic corrosion, a preload spring that applies preload to the rolling bearing is provided in the gap between the rolling bearing and the bracket. And the method of making it bypass to a brush is used (for example, refer patent document 2).
In addition, measures have been taken to use non-conductive balls such as ceramic balls for the bearing portion.
Japanese Patent Laid-Open No. 9-93845 JP 2003-324889 A

As described above, as a method of preventing electric corrosion, the method of avoiding harmonic voltage and current generated in the mover with a brush requires maintenance of brush replacement due to brush wear, and the brush powder is inside the motor and bearing. Alternatively, scattering to the periphery has a problem of damaging the motor and bearings or adversely affecting external devices. Then, since the life of parts due to wear is not so long, the brush is insufficient to avoid the harmonic voltage and current generated in the mover stably.
Further, the method of preventing electrolytic corrosion by using a non-conductive ball or the like for the bearing portion has a problem that the parts are expensive.
The present invention has been made to solve such problems, and is inexpensive, maintenance-free, and can easily avoid harmonic voltages and currents generated in the mover. An object is to provide a prevention device.

In order to achieve the above object, an electric corrosion prevention device for an electric motor according to the present invention includes an armature wound with a drive winding, an armature and a magnetic gap, and a laminated iron core. A magnetic field comprising a secondary side formed by mounting a plurality of conductor bars or magnets, and a bearing for movably supporting either the armature or the field, the armature and the In an electric motor configured to move relatively with one of the field magnets as a mover and the other as a stator, a primary coil provided on the armature side and wound around a first ferrite core; The primary coil and a secondary coil wound around a second ferrite core are provided on the field side through a gap, and are conducted between the mover and the stator via the bearing. It is characterized by bypassing the current
According to a second aspect of the present invention, in the electric corrosion prevention apparatus for an electric motor according to the first aspect, the primary coil is a neutral point of a Y-connection of a drive winding in the armature and a support that supports the armature. It is connected between them.
According to a third aspect of the present invention, in the electric corrosion prevention device for an electric motor according to the first aspect, an element such as an LED is connected to the secondary coil so that it can be confirmed that an axial current flows on the field side. Is.

According to the first and second aspects of the present invention, the armature wound with the drive winding, the armature and the armature are arranged to face each other through a magnetic gap, and a plurality of conductor bars or magnets are mounted on the laminated core. And a bearing that is supported so as to be movable between the armature and the field through a support. The motor is provided on the armature side and wound around the first ferrite core. Since the primary coil and the secondary coil provided on the field side and wound around the second ferrite core are provided, the current flowing through the rolling bearing or the linear guide when the motor is driven by a commercial power source Since it can avoid and bypass to the bypass means which consists of a primary coil and a secondary coil, the problem of the electrolytic corrosion of a bearing can be prevented.
Further, according to the third aspect, by providing the detection means on the secondary coil side, it is possible to check whether the electric motor is likely to cause electrolytic corrosion.

  Embodiments of the present invention will be specifically described below with reference to the drawings.

1A and 1B show a rotary electric motor according to a first embodiment of the present invention, in which FIG. 1A is a side sectional view thereof, and FIG. 1B is a block diagram for explaining an electrical decoration preventing apparatus. Note that the description of the same constituent elements of the present invention as those of the prior art will be omitted, and different points will be described.
In the figure, 12 is a primary coil, 13 is a secondary coil, 14 is a resistor, and 15 and 16 are ferrite cores.
The present invention is different from the conventional example as follows.
That is, it is provided on the armature 4 side constituting the stator, and is provided on the rotor 8 of the field 10 via the primary coil 12 wound around the first ferrite core 15 and the primary coil 12 and the air gap. In addition, a secondary coil 13 wound around the second ferrite core 16 is provided.
Specifically, as shown in FIG. 1B, the primary coil 12 is connected between the neutral point of the Y connection of the drive winding 3 in the armature 4 and the frame 1. A resistor 14 is connected to the secondary coil 13 provided on the rotor 8 side, and the current bypassed from the primary coil 12 to the secondary coil 13 is converted into heat by the resistor 14. Instead of the resistor 14 installed on the field side, an element (not shown) such as an LED may be connected to the secondary coil 13 so that it can be confirmed that an axial current flows on the field side. Absent.
Since the first embodiment has such a configuration, the current flowing into the bearing 11 from the rotor 8 side is avoided, and the bypass means including the primary coil 12 and the secondary coil 13 is bypassed, and the bracket 5.6, the frame 1 Therefore, the problem of electrolytic corrosion of the bearing 11 can be prevented.

FIG. 2 is a side view of a direct acting motor according to a second embodiment of the present invention. In the present embodiment, a moving magnet type linear motor having a field on the mover side and an armature on the stator side will be described.
In the figure, 21 is a base as a fixed base, 22 is a permanent magnet, 23 is a table made of a magnetic material, 24 is a field, 25 is an armature, 26 is a linear guide, 27 is a primary coil, and 28 is a secondary coil. , 29 are resistors, and 30, 31 are ferrite cores. The armature core and the armature winding are not shown.
The second embodiment is applied to a direct acting type instead of the rotary type of the first embodiment. Specifically, the first ferrite core 30 is wound around the base 21 side provided with the armature 25. A configuration in which a rotated primary coil 27 is installed, and a secondary coil 28 wound around the second ferrite core 31 is provided on the side of the table 23 having the field 24 via the primary coil 27 and a gap. It is.
Specifically, the primary coil 27 is connected between the neutral point of the Y connection of the drive winding (not shown) in the armature 25 and the base 21. Further, a resistor 29 is connected to the secondary coil 28 provided on the table 23 side, and the current bypassed from the primary coil 27 to the secondary coil 28 is converted into heat by the resistor 29. As in the first embodiment, instead of the resistor 29 installed on the secondary side (field side), an LED or the like is provided on the secondary coil so that it can be confirmed that axial current flows on the field side. These elements (not shown) may be connected.
Since the second embodiment has such a configuration, the current flowing into the linear guide 26 from the base 21 side can be avoided, bypassed by the bypass means including the primary coil 27 and the secondary coil 28, and released to the table 23. Therefore, the problem of electrolytic corrosion of the linear guide can be prevented.

FIG. 3 is a side view of a direct acting motor according to a third embodiment of the present invention. In this embodiment, an explanation will be given using an example of a moving coil linear motor having an armature on the mover side and a field on the stator side.
In the figure, 32 is a field yoke.
The third embodiment is different from the second embodiment in that a primary coil 27 wound around a first ferrite core 30 is installed on the side of the table 23 provided with the armature 25 and a field 24 is provided. On the base 21 side, a secondary coil 28 wound around the second ferrite core 31 is provided via a primary coil 27 and a gap.
The primary coil 27 is connected between the neutral point of the Y connection of the drive winding (not shown) in the armature 25 and the table 23. Further, a resistor 29 is connected to the secondary coil 28 provided on the base 21 side, and the current bypassed from the primary coil 27 to the secondary coil 28 is converted into heat by the resistor 29. In the same way as in the second embodiment, instead of the resistor 29 installed on the field side, an element such as an LED (non-reset May be connected.
Since the third embodiment has such a configuration, the current flowing from the table 23 to the linear guide 26 can be avoided, bypassed by the bypass means including the primary coil 27 and the secondary coil 28, and released to the base 21 side. Therefore, the problem of electrolytic corrosion of the linear guide can be prevented.

  The present invention can be applied not only to automation equipment in the FA field such as machine tools and semiconductor manufacturing apparatuses, but also to wind and hydraulic power machines, construction / civil engineering machines, etc., using a synchronous motor or an induction motor driven by an inverter as a drive source.

BRIEF DESCRIPTION OF THE DRAWINGS It is a rotary electric motor which shows 1st Example of this invention, Comprising: (a) is the sectional side view, (b) is a block diagram for demonstrating the electrical decoration prevention apparatus Side view of direct acting motor showing second embodiment of the present invention. Side view of direct acting motor showing third embodiment of the present invention Side sectional view of a motor showing a conventional example

Explanation of symbols

1 frame,
2 Armature core (laminated core),
3 Winding for driving,
4 Armature,
5, 6 bracket,
7 rotation axis,
8 Rotor (laminated core),
9 Permanent magnet,
10 Field,
11 Rolling bearings,
12 primary coil,
13 Secondary coil,
14 Resistance R
21 base,
22 permanent magnet 23 table,
24 field,
25 Armature,
26 Linear guide 27 Primary coil,
28 Secondary coil 29 resistance,
30, 31 Ferrite core 32 Field yoke

Claims (3)

An armature wound with a winding for driving;
A magnetic field that is disposed opposite to the armature via a magnetic gap, and that constitutes a secondary side formed by mounting a plurality of conductor bars or magnets on the laminated core,
A bearing for movably supporting either the armature or the field;
With
In the electric motor configured to move relative to either the armature or the field as a mover and the other as a stator,
A primary coil provided on the armature side and wound around a first ferrite core;
A primary coil and a secondary coil wound around a second ferrite core and provided on the field side through a gap;
An electric corrosion prevention device for an electric motor, wherein a current conducted through the bearing is bypassed between the mover and the stator.   The electric corrosion of the electric motor according to claim 1, wherein the primary coil is connected between a neutral point of Y connection of a drive winding in the armature and a support body that supports the armature. Prevention device.   2. The electric corrosion prevention apparatus for an electric motor according to claim 1, wherein an element such as an LED is connected to the secondary coil so that it can be confirmed that an axial current flows on the field side.

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