JPH04117148A - Electric rotating machine - Google Patents

Abstract

PURPOSE:To protect a bearing from electrolytic corrosion and to realize long term stabilization by constituting a mirror cover, frame, and the like through a creep resistant insulator scarcely subjected to permanent compression deformation and holding an insulator having high tracking resistance, scarcely subjected to water absorption or dust adhesion, between mirror cover components at a part where the creep resistant insulator exposes to the outer air or to the interior of an electric rotating machine. CONSTITUTION:Creep resistant insulators 17a1, 17b1, which are scarcely subjected to permanent compression deformation, are inserted between a part A, to be fitted with mirror covers 5a, 5b, and a part B and secured in place. Furthermore, insulators 29a, 29b having high tracking resistance and scarcely subjected to water absorption or dust adhesion even upon occurrence of permanent compression deformation are secured, while being held between the mirror covers 5a, 5b at parts exposed to the outer air and to the interior of an electric rotating machine. At the same time, the insulators 29a, 29b are extended in the fitting face direction (axial direction) and the abutting face direction (radial direction) in order to ensure sufficient creeping distance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to a rotating electric machine, such as a vehicle mutual electric motor, in which the insulation structure of a bearing portion of the rotating electric machine is improved.

(Prior Art) Conventionally, an example of the structure of a main motor (hereinafter referred to as a rotating electric machine) of a railway vehicle is shown in FIG. 6 (a sectional view with the lower half omitted), in which the stator frame 1 is It is divided into a cylindrical frame main body 1a and an annular frame subbody 1b. An annular stator core 2 is fixed to the inner periphery of the frame main body 1a by being pressed from both ends by stator core holders 3, 3. A stator is constructed by assembling stator coils 4 into a large number of slots 2a formed in the inner circumferential surface of stator core 2.

Further, one end of the mirror cover 5b is fixed to one end of the frame main body 1a with a bolt 15, and the bolt 15 is attached to the other end of this mirror M5b.
to fix one end of the mirror cover 5a, and also fix the frame subbody 1b.
Fix the housing 6 to one end of the
Bearings 7.7 are provided on the housing 6 and the mirror cover 5a, respectively.
Assemble the bearings 7.7 and 8.
is rotatably supported.

A rotor core 9 is attached to this shaft 8 with a rotor core holder 1.
It is fixed by pressing it from both ends with 0.10. and,
A large number of slots 9a formed on the outer peripheral surface of the rotor core 9
Assemble the rotor bar 11 to the rotor bar 11.
A ring-shaped short circuit ring 12 is welded to both ends of the squirrel cage rotor.

Further, the fan 14 is fitted onto the shaft 8, and the shaft 8
The rotation of the rotor causes cooling air to flow into the rotating electric machine, thereby preventing the stator coil 4, rotor bar 11, and short circuit ring 12 from being heated. The cooling air flowing inside the rotating electric machine is generated by sucking outside air directly or through a simple ventilation filter (not shown) through a suction port 13 provided in a part of the frame main body 1a, and by sucking the outside air directly or through a simple ventilation filter (not shown) through a fan at the other end of the frame main body 1a. It is again discharged to the outside of the rotating electric machine from the discharge port 16 located on the outer periphery of the rotary electric machine 14. Therefore, the inside of the rotating electric machine is gradually contaminated by the cooling air generated by the outside air, and after a long period of use, the inside of the rotating electric machine becomes almost as dirty as the outside of the rotating electric machine.

The example shown in Fig. 6 has a self-ventilation fan structure in which the fan 14 is firmly fitted to the shaft 8, but an external blower is used to forcibly blow outside air (cooling air) into the rotating electrical machine. A similar situation occurs in the case of the ventilation method.

In the rotating electric machine configured in this manner, the rotor rotates when energized, and the rotational force is transmitted from the shaft end of the shaft 8 to the drive gear device via a coupling (not shown) to drive the vehicle. When the rotor begins to rotate due to energization, unnecessary magnetic flux is generated in the shaft 8 due to the rotational movement. This magnetic flux interlinks with the shaft 8 or becomes an axial magnetic flux to generate an axial voltage. There are other causes of this shaft voltage, such as armature reaction of irregular groove winding, static charge, and return current flowing into the rail. Electric current flows through and breaks the slight oil film formed for lubrication.1. This causes the arc to fly and roughen the rolling surface of the bearing 7 (hereinafter referred to as "electrolytic corrosion"), reducing the life of the bearing 7.

Metal abrasion powder is produced from the rough raceway surface and mixes with the lubricating oil (grease), degrading the lubricating oil and reducing the life of the bearing 7 at an accelerating rate.If the conditions are very bad, bearing burnout and rotation may occur. Child lock accidents may occur.

For this reason, the following measures have been taken in conventional rotating electric machines. This is a method in which an electric insulator is placed in a part of the circuit to cut off the current so that no current flows to the bearing 7 due to the generated shaft voltage. That is, in FIG. 6, the frame main body 1a and the frame sub-body 1
Creep-resistant insulator 1 between b and between mirror cover 5a and 5b.
7 are inserted respectively. The details will be explained with reference to FIGS. 8 and 9, taking the space between the mirror covers 5a and 5b as an example.
Since the frame main body 1a and the frame sub-body 1b have the same structure, their explanation will be omitted.

2 with an L-shaped cross section on the fitting part of the mirror covers 5a and 5b and on the body mounting surface.
The two creep-resistant insulators 17a and 17b are sandwiched, and the mirror lid 5a is tightened and fixed using the screw holes 18 and bolts 15 formed in the mirror lid 5b to form a mirror m5a.

5b. Then, insert a bobbin 19 made of a creep-resistant insulator into the loose insertion hole 21 formed in the mirror cover 5a, insert the bolt 15 into the bobbin 19, and screw the bolt into the screw hole 18 of the mirror cover 5a. A bobbin 19 is sandwiched between the bolt 15 and the mirror cover 5a, and the bolt 15 and the bobbin 19 are completely covered and wrapped with a sealing material 20.

The mirror covers 5a and 5b configured in this manner have an insulating material 17 in order to have a structure that can withstand intense vibrations when the vehicle is running.
are firmly tightened and fixed with fitting force and bolts 15.

For this reason, it was necessary to use a material with very little permanent compression deformation (creep) of the insulator, and to minimize the effect of this, it was necessary to make the insulator as thin as possible.

On the other hand, if an inorganic material with low creep deformation was used as an insulator, it would be difficult to mold it into the shape and dimensions shown in the figure, and trying to make something close to it would be extremely expensive and nearly impossible. .

Under the above circumstances, materials with less creep deformation (e.g. epoxy resin molded glass laminated rings, high hardness rubber, polyphenylene sanamide, etc.) and a thickness of 03 to 2 mm that have an insulating effect are recommended. It is used.

With this configuration, the mirror covers 5a and 5b are completely electrically insulated, and even if shaft voltage occurs, the current is completely cut off, so the bearing 7 is free from electrolytic corrosion and has a long life. It becomes something that can realize the transformation.

(Problems to be Solved by the Invention) However, even with the conventional improved insulation structure (to prevent electrolytic corrosion) of the bearing 7 having the structure described above, there are the following problems, and it is difficult to maintain the insulation effect of the insulator. was very difficult.

■As shown in the detailed sectional view of part B in Figure 8 [Figure 9 (b)], the thickness (1) of the insulator 17a is relatively thin, so dust containing moisture C If iron powder or iron powder C adheres to the insulating material 17a, conduction will occur between the mirror covers 5a and 5b, so the effectiveness of the insulating material is lost and the bearing 7 often suffers from electrolytic corrosion.

■In order to improve the above-mentioned problems, as shown in the detailed cross-sectional view of section A in Figure 8 [Figure 9 (a)], the insulator 17b
Is there a way to extend the creepage distance (N) sufficiently to prevent the electricity from creeping and short circuiting even if dust C adheres? Creep-resistant insulators are generally not water-resistant enough, and Due to the poor tracking resistance (resistance to creepage short circuit), this method also reduces the insulation effect as the insulator gradually absorbs moisture and attracts dust when used for a long time. Therefore, electrolytic corrosion of the bearing 7 The countermeasures were insufficient.

The purpose of the present invention is to prevent galvanic corrosion of hair rings caused by insulators, and to provide long-term protection without being affected by environmental conditions during operation.
It is an object of the present invention to provide a rotating electric machine having a bearing electrolytic corrosion prevention structure that can maintain the insulation effect.

[Structure of the Invention (Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention provides a cylindrical frame equipped with a stator with a mirror cover at one end and a bearing housing at the other end that can be disassembled. The mirror cover and the bearing housing rotatably support a rotating shaft equipped with a rotor corresponding to the stator through bearings, and at least the mirror cover, the bearing housing, and the frame Divided portions are formed along the periphery of the rotating shaft at two locations, and a creep-resistant insulator with little permanent compression deformation is interposed in each of the divided portions for electrical insulation. An insulating material with good tracking resistance is disposed on the outer peripheral portion exposed inside the frame or outside the frame, and the divided portions are fastened together with a fastener.

(Function) According to the present invention, a creep-resistant insulator is provided in the mirror cover, the bearing housing, and the divided portion of the frame, and an insulator with good tracking resistance is provided on the outer periphery of the insulator, so that it is possible to avoid damage caused by severe damage such as when the vehicle is running. The amount of permanent compression deformation is small to maintain the strength and rigidity of the mirror lid that can withstand vibrations, and even if the permanent compression deformation is large in the creep-resistant insulator or the parts exposed to the outside air or the inside of the rotating electric machine, water absorption is small. Therefore, the measures to prevent galvanic corrosion of the bearing can be effectively maintained for a long period of time.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 shows the main part of the first embodiment, that is, A of FIG.
FIG. 3 is a detailed partial cross-sectional view of parts B and B. FIG. Mirror lid 5a
Creep-resistant insulators 17a1 and 17b that are unlikely to cause permanent compression deformation in the part A that is fitted to the parts A and B that are attached to the body.
1 is sandwiched and fixed. Furthermore, insulators 29g and 29b with good tracking resistance, which may undergo permanent compression deformation but are difficult to absorb water and dust, are sandwiched between the mirror covers 5a and 5b in the parts exposed to the outside air and the inside of the rotating electric machine. It extends in the direction of the fitting surface (axial direction) and in the direction of the mounting surface (radial direction) in order to secure a sufficient creepage distance.

As the creep-resistant insulators 17a1 and 17b1, an epoxy glass laminate, high hardness urethane rubber, polyphenylin sanamide, or the like is used. Further, Teflon or the like is used as the insulator 2gB29b having good tracking resistance.

In addition, two creep-resistant insulators 17al each having an L-shaped cross section are provided at the fitting portion of the mirror covers 5a and 5b and at the mounting surface.

17b1 is inserted into the screw hole 18 machined in the mirror cover 5b.
Tighten and fix the mirror cover 5a with the bolts 15 and
b, and a loose insertion hole 21 formed in the mirror cover 5a.
A bobbin 19 made of a creep-resistant insulator is inserted into the bobbin 19, and a bolt 15 is inserted into the bobbin 19.
A bobbin 19 is inserted between the bolt 15 and the mirror cover 5a by screwing into the screw hole 18 of the bolt 15, and the bolt 15 and bobbin 19 are completely covered and wrapped by the sealing material 20.

In the case of the insulating structure of the embodiment configured in this way, the mirror cover 5
The mechanical strength and rigidity of the mirror covers 5a and 5b are maintained because creep-resistant insulators 17a1 and 17bl, which are unlikely to cause permanent compression deformation, are provided at the fitting portions of the mirror covers 5a and 5b. In addition, insulators 29a and 29b with good tracking resistance are provided in the parts of the creep-resistant insulators 17al and 17bl that are exposed to the outside air and the inside of the rotating electric machine, making it difficult for water absorption and dust to adhere, and further reducing the creepage distance. Because it is long, it does not absorb water, has little dust adhesion, and even if a small amount of dust adheres, it has a sufficient creepage distance, so the insulating effect hardly decreases and the insulator structure has stable electrolytic corrosion protection over a long period of time. be able to maintain it.

Next, second to fifth embodiments of the present invention will be described.

FIG. 2 shows only the essential parts of the second embodiment, in which the insulator 29a in the first embodiment described above is fixed by providing a stepped stopper 30 formed on the mirror cover 5a. It is something.

FIG. 3 shows only the main part of the third embodiment.
As shown in the figure, the insulator 29bl is extended and fixed in the central axis direction, and in the B part, the insulator 29a1 is attached in the radial direction as shown in the figure, and a stopper 31a is attached to the mirror cover 5a, and a stopper 31a is attached to the mirror cover 5b. It is fixed by providing a stopper 31b.

FIG. 4 shows only the main parts of the fourth embodiment, in which the stoppers 31a and 31b in FIG. 3 are formed into tapered stoppers 31a1 and 31bl.

FIG. 5 shows only the main part of the fifth embodiment, in which an insulator 29c with good tracking resistance is provided in the part of one bobbin in FIG. 1 exposed to the outside air and inside the rotating electric machine. It is.

In the second to fifth embodiments described above, the same effects as in the first embodiment can be obtained.

Furthermore, in the components of each of the embodiments described above, a sealing material is filled between the insulator with good tracking resistance and the insulator with creep resistance, or between the insulator with good tracking resistance and the component that holds it in between. This structure further improves reliability.

[Effects of the Invention] According to the present invention, since the mirror lid or frame is constructed using a creep-resistant insulator with little permanent compression deformation, its strength and rigidity are sufficiently ensured, and the creep-resistant insulator is protected against external air. Alternatively, the parts exposed inside the rotating electrical machine are constructed by sandwiching an insulating material with good tracking resistance that does not absorb water or attract dust between parts that make up the mirror cover or frame, so that the bearing's electrical current is not affected. We have created a rotating electric machine with an ideal bearing corrosion prevention structure that not only prevents corrosion, but also prevents the deterioration of tracking resistance due to a decrease in creepage distance due to water absorption and dust adhesion, and maintains stable insulation properties for a long period of time. Can be provided.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing only the main parts of the first embodiment of the present invention, and FIGS. 2 to 5 are sectional views showing only the main parts of the second to fifth embodiments of the invention, respectively. Fig. 6 is a cross-sectional view showing only the upper half of an example of a conventional rotating electrical machine, Fig. 7 is a diagram for explaining the shaft current flowing in the rotating electrical machine due to the shaft voltage in Fig. 6, and Figs. FIG. 9 is a sectional view showing the mirror lid portion of FIG. 6 in detail. 1a...Frame main body, 1b...Frame subsidiary body, 5
a, 5b... Mirror cover, 7... Bearing (bearing) 8.
...Shaft, 17, 17a, 17b... Creep-resistant insulator, 14... Screw hole, 15... Bolt, 16...
...Loose insertion hole, 19...Bobbin made of creep-resistant insulator, 25-=sealing material, 29a, 29b. 29al, 29bl, 29aal, 29cm...
Insulator with good tracking resistance.

Claims (1)

[Claims] A mirror cover is attached to one end of a cylindrical frame provided with a stator, and a bearing housing is attached to the other end by removable coupling means, and the mirror cover and the bearing housing are connected to each other via bearings. rotatably supporting a rotating shaft having a rotor corresponding to the stator, forming divided portions along the circumference around the rotating shaft at at least two places in the mirror cover, the bearing housing, and the frame; Creep-resistant insulators with low permanent compression deformation are interposed in each divided portion to electrically insulate them, and tracking-resistant A rotating electric machine in which a good insulator is arranged and the divided parts are fastened with a fastener.