JPH09322469A - Stator of dynamo-electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the vibration of the bottom wall of a stator frame main part which is produced by an electromagnetic vibration force, suppress the noise while a dynamo-electric machine is in operation and, further, make the manufacture of the machine easy. SOLUTION: A stator is composed of a stator frame 1 which has the bottom wall 3 of a stator frame main part 2, side walls 4 which are stood on both the edge parts of the bottom wall 3 in its radial direction, linking walls 6 and 7 and their outer walls 6a and 7a which link the side walls 4 with each other and a plurality of axial direction ribs which are extended in the axial direction of the stator and which are cylindrically provided inside the stator frame main part 2 and a stator core which is composed of layer-built steel plates and fitted to the cylindrically arranged inside parts of a plurality of the axial direction ribs and supported. The side walls 4 and the bottom wall are divided into (m) blocks and (n) blocks (where (m) and (n) denote the number of nodes of vibration modes) and weights whose individual weights are not less than 1/5 of the weights of the respective blocks are attached to the blocks at the centers of the loops of the vibration modes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stator of a rotating electric machine suitable for a large rotating electric machine of several hundred kW class used for a pump, a refrigerator, a blower and the like.

[0002]

2. Description of the Related Art An example of a stator of a rotary electric machine of this type is shown in FIG.
5 to 20. 15 to 18, the main body 2 of the stator frame 1 includes a bottom wall 3, side walls 4 and 5 standing upright on both ends of the bottom wall 3 in the radial direction, and an axial direction of the bottom wall 3. It is erected on both end sides and is erected on the axial center of the connecting walls 6 and 7 and the bottom wall 3 for connecting the ends of the both side walls 4 and 5, and the center of each of the both side walls 4 and 5. Reinforcing wall 8 for connecting parts
And is configured. Here, the connecting walls 6 and 7 are composed of outer walls 6a and 7a and inner walls 6b and 7b, respectively. The outer surfaces of the outer walls 6a and 7a are mounting surfaces for mounting the bearing bracket. The connecting wall 6,
7 and the reinforcing wall 8 are formed with through-holes 8a having substantially the same diameter as the outer diameter of the stator core 9 and having a substantially circular shape in order to take the stator core 9 in and out (only for the reinforcing wall 8). (Shown in FIG. 18).

Inside the stator frame main body 2, a plurality of axial ribs 10a-1 extending in the axial direction (for example, 10 ribs) are formed.
0j is arranged in a cylindrical shape. In this case, both ends of the axial ribs 10a to 10j have inner walls 6b of the connecting walls 6 and 7,
7b is integrally connected to the reinforcing wall 8 at the center.
Are integrally connected to each other. Then, the stator core 9 is press-fitted and fitted and supported inside the axially arranged ribs 10a to 10j.

[0004]

However, in the conventional structure, the electromagnetic exciting force of the stator core 9 generated by the electromagnetic exciting force of the stator core 9 passes through the reinforcing wall 8 and the side walls 4, 4 of the stator frame body 2. 5 and the bottom wall 3 and resonates in accord with the natural frequencies of the side walls 4, 5 and the bottom wall 3. For this reason, when the output of the rotating electric machine is large, the vibrations of the side walls 4, 5 and the bottom wall 3 may be considerably large, and noise during operation may be large.

Further, in recent years, the speed of an electric motor is often controlled by an inverter. In the speed control by the inverter, the voltage and current waveforms are distorted to generate magnetic flux harmonics in the stator core 9 of the motor, and the frequency of the electromagnetic exciting force and the natural vibrations of the side walls 4, 5 and the bottom wall 3 are generated. There is a resonance problem that matches the number, and it makes a lot of noise. In the case of speed control using these inverters, the frequency is variable and it is difficult to avoid resonance.

The electromagnetic excitation force is classified into a fundamental wave magnetic flux and a slot harmonic magnetic flux generated by the influence of the slots of the stator core 9 and the rotor. Of these, the electromagnetic excitation force due to the fundamental wave magnetic flux has a frequency twice the power supply frequency fo. Further, the electromagnetic excitation force due to the slot harmonic magnetic flux differs depending on the combination of the number of slots Qs of the stator 9 and the number of slots Qr of the rotor and the number of magnetic poles P, and the generation frequency fe is expressed by the equation (1). .

[0007]

[Equation 1] Becomes However, S is a slip.

The frequency fe generated by the slot harmonic magnetic flux is about 1000 Hz to 2000 Hz. However, when the vibration frequency, which is the electromagnetic vibration force, is close to or coincides with the natural frequencies of the bottom wall 3 and the side walls 4 and 5, the vibration is expanded and large vibration and noise are generated. Occurs.

19 and 20 show measured natural vibration modes of the resonated frequencies of the side walls 4, 5 and the bottom wall 3. It was found that this vibration mode represents a vibration mode having the nodes m and n of the peripheral supporting rectangular plate.

As a structure for solving such a drawback, a stator as shown in FIG. 21 is considered. In this structure, the axial ribs 11 are provided on both sides of the outer peripheral portion of the stator core 9.
While the a and 11b are welded, the axial ribs 11a and 11b are placed and supported on the support bases 14a and 14b which are provided on the bottom wall 13 of the stator frame body 12 so as to project upward. . According to the above configuration, the axial rib 11a,
Since 11b does not come into contact with the side wall 15 of the stator frame main body 12, the vibration of the side wall 15 can be reduced. Therefore, even when the output of the rotating electric machine is large, the vibration of the side wall 15 can be reduced and the noise during operation can be reduced.

However, in the case of the above construction, there is a problem that the concentric adjustment work between the iron core of the stator iron core 9 and the shaft center of the bearing bracket attached to the stator frame body 12 is very troublesome and the productivity is considerably deteriorated. It was

Therefore, an object of the present invention is to reduce the bottom wall and vibration of the stator frame body due to the electromagnetic excitation force, and
It is an object of the present invention to provide a stator of a rotary electric machine that can reduce noise during operation and improve manufacturability.

[0013]

According to a first aspect of the present invention, a bottom wall of a stator frame main body, side walls erected on both side edges of the bottom wall in the radial direction, and a connecting wall connecting the side walls. An outer wall of the connecting wall, a stator frame formed by cylindrically arranging a plurality of axial ribs extending in the axial direction inside the stator frame main body, and a stack of steel plates inside the axial ribs. In a stator of a rotary electric machine provided with a stator core that is fitted and supported, the vibration mode nodes m and n are divided at the center of each position of the vibration mode antinode with respect to the surfaces of the side wall and the bottom wall. The feature is that weight of 1/5 or more of each block is attached.

According to this structure, even if the natural frequencies of the side wall and the bottom wall and the frequency of the electromagnetic excitation force match, the weight is fixed to the portion where the vibration amplitude of the antinode of the vibration mode is large, so that the natural vibration occurs. The number can be reduced, resonance can be avoided with respect to the frequency of the electromagnetic excitation force, and a noise reduction effect can be obtained.

According to the second aspect, the weight is provided on the side wall and the bottom wall,
It is characterized by mounting with screw holes, welding, through holes, magnets, and adhesive fixing. According to this configuration, the method of fixing the weight may be changed, so that the structural property can be further improved. Further confirmation test at the time of manufacturing completion,
Or even if the noise increases after installation or on-site installation, the weight can be changed and the structure can be installed.
Noise reduction effect can be obtained.

A third aspect of the present invention is characterized in that the weight is attached to the maximum displacement point of the antinode of the vibration mode by fixed point contact. According to this structure, the weight is attached to the maximum displacement point of the antinode of the vibration mode by the point contact fixing, and the rate of decrease in the natural frequency is maximized. That is, by fixing the surface and the line contact, the rigidity is increased as a reinforcing effect for the side wall and the bottom wall, and the natural frequency is increased. However, since the weight does not increase by making point contact with the weight and the weight of the weight works effectively, the rate of decrease in natural frequency can be increased, resonance can be avoided, and noise can be reduced.

A fourth aspect of the present invention is characterized in that the node of the vibration mode of the side wall and the node of the vibration mode of the bottom wall, or the node of the vibration mode of the side wall and the node of the vibration mode of the bottom wall are connected by a reinforcing material. . According to this configuration, the node of the vibration mode, that is, the portion that does not vibrate serves as the fixed end, and the antinode of the vibration mode is coupled with the reinforcing agent, so that the vibration of the antinode of the vibration mode is suppressed and the noise damping effect is obtained.

According to a fifth aspect of the invention, the antinodes and antinodes of the same vibration mode of the side wall and the bottom wall are connected by a reinforcing plate, and the antinodes of antiphase vibration mode between the antinodes of the same vibration mode and antinodes. The feature is that a damping material is interposed in the part to be turned. According to this configuration, the antiphase antinode and the antinode portion of the vibration mode undergo the maximum relative displacement with respect to the antiphase antinode portion, and the damping material is present at the location of the maximum relative displacement. As it expands and contracts, internal friction occurs, vibration is suppressed, and a noise damping effect is obtained.

According to a sixth aspect of the present invention, among the plurality of axial ribs, the damping material is interposed between the axial rib located under the stator core, the bottom wall, and the stator core. Have. According to this configuration, relative displacement is generated with respect to the joint portion of the stator core, the bottom wall, and the rib, and the damping material expands and contracts at the portion where the relative displacement occurs, causing internal friction, which causes bottom wall vibration. Is suppressed and a noise damping effect is obtained.

A seventh aspect of the present invention is characterized in that the damping material is elastic rubber or epoxy resin. According to this configuration,
Utilizing that the damping material is made of elastic rubber or epoxy resin, the internal damping becomes much larger than that of the metallic material of steel, and the damping material expands and contracts at the part where the relative displacement occurs, and the vibration damping action Reduces noise.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) A first embodiment corresponding to claim 1 of the present invention will be described below with reference to FIGS. The description of the components having the same reference numerals as those of the conventional rotary electric machine will be omitted.

First, as shown in FIGS. 1 to 3, with respect to the surfaces of the side walls 4 and 5 and the bottom wall 3 surrounded by the connecting walls 4 and 5 of the stator frame main body 2 and the connecting wall outer walls 6 and 7, A weight 16 that is ⅕ or more of the weight of each block divided by the nodes m and n of the vibration mode is attached to each center R of the antinode of the vibration mode.

According to this structure, the side walls 4, 5 and the bottom wall 3 are formed.
The natural frequency of can represent the vibration system of the peripheral rectangular plate. That is, as shown in FIG. 19, the vibration mode has the number of nodal lines of m and n parallel to the long side a and the short side b.
Further, the natural frequency Wn of the peripheral rectangular plate can be obtained by the equation (2).

[0024]

[Equation 2]

Here, m and n are the number of nodal lines parallel to the sides a and b, t is the plate thickness, E is Young's modulus, g is gravitational acceleration, and r is
Is the weight per unit volume. However, the problem that the natural frequency and the frequency of the electromagnetic excitation force resonate is between 1000 Hz and 2000 Hz, and as shown in FIG.
There are three vibration modes from 1, n = 1 to m = 1 and n = 3, and the mode numbers are limited to only 3rd, 4th and 5th.

Therefore, depending on the vibration mode, the weight 16
Is attached to the center R of each of the side walls 4, 5 and the bottom wall 3 divided into (n + 1) sides in the axial direction a and divided in two into the side b in the direction orthogonal to the axis, thereby increasing the weight and decreasing the natural frequency. In addition, the increase in weight suppresses the occurrence of vibration.

Further, in this case, since the weight of the weight 16 is ⅕ or more of the divided weight, the natural frequency is reduced by about 10% as calculated from the equation (2), and the influence of resonance is exerted. Disappear.

Furthermore, by attaching weights 16 to the antinodes of the side walls 4, 5 and the bottom wall 3 in the natural vibration mode,
It was also found from the measurement that the natural frequency can be reduced by more than 10%.

Therefore, in the operation with the commercial power supply of 50 Hz and 60 Hz, the generation frequency of the electromagnetic exciting force can be calculated from the equation (1), and the natural frequency and the vibration mode can be obtained from the calculation from the equation (2). Can be predicted in advance. Further, since the problematic natural frequency is a fixed frequency in the case of a commercial power supply, the position where the weight 16 is attached is determined by the vibration mode, which effectively reduces the target natural vibration. . For example, as shown in FIG. 4, the power supply frequency is 60 Hz, and the frequency of the electromagnetic excitation force is 1750 Hz from the equation (1). Conventional frequency is 1750
As shown in FIG. 4 (a), the noise when resonating was high, and an extremely large noise component of 1750 Hz was detected.

Therefore, by applying this embodiment,
As shown in FIG. 4C, the natural frequency can be reduced to 1680 Hz (the solid line in this embodiment and the broken line in the conventional example).
When the mode number 5th resonates as shown in (4), eight weights 16 are attached to the antinode of the vibration mode. To see this effect, the result of noise measurement is shown in Fig. 4 (b).
As shown in (1), it can be seen that the target natural frequency is appropriately reduced, and the dominant frequency of noise, 1750 Hz, is reduced.

Further, FIG. 5 shows the noise level when the power supply frequency changes in the inverter operation. From this result, it can be seen that the frequency of the peak is lowered, and in the present invention, the weight of the weight 16 is increased even if resonance occurs, so that the vibration is suppressed and the noise peak is reduced. Therefore, the vibration and noise of the entire rotating machine can be reduced.

(Second Embodiment) FIG. 6 shows the second aspect of the present invention.
2 shows a second embodiment corresponding to the weight 16
It is shown that the mounting is done by screw holes, welding, through holes, magnets, and adhesive fixing. Since the mounting method may change in this way, the mounting is simplified and the manufacturability is improved. You can Also, the shape of the weight is
Although the one shown in FIG. 6 is a cube, it may have any shape.

(Third Embodiment) FIG. 7 shows claim 3 of the present invention.
In the third embodiment corresponding to, the weight 16 is attached to the maximum displacement point R of the antinode of the vibration mode by point contact fixation.

According to this construction, the area of the weight 16 contacting the side walls 4, 5 or the bottom wall 3 is kept small. Therefore, by fixing the maximum displacement point R of the antinode of the vibration mode by fixed point contact, the reduction rate of the natural frequency becomes maximum. In other words, by fixing the surface and the line contact, the side wall and the bottom wall are reinforced and the rigidity is increased and the natural frequency is increased. Therefore, weight 1
By making point contact with 6 the rigidity does not increase and the weight 1
Since the weight of 6 works effectively, the natural frequency can be greatly reduced with a small weight, resonance can be avoided, and a noise reduction effect can be obtained.

(Fourth Embodiment) FIGS. 8 and 9 show a fourth embodiment corresponding to claim 4 of the present invention, in which the antinodes of the side walls 4 and 5 in the vibration mode and the bottom wall 3 vibrate. The mode node, or the node of the vibration mode of the side walls 4 and 5 and the antinode of the vibration mode of the bottom wall 3 are connected by the reinforcing material 17. Also in this configuration, since the antinode of the vibration mode has a large amplitude as shown in FIG. 9, by fixing the connecting member 17 to the node of the vibration mode of the small amplitude, the amplitude of the antinode of the vibration mode is suppressed and the vibration is reduced. Reduce. Therefore, the vibration and noise of the entire rotating machine can be reduced.

(Fifth Embodiment) FIGS. 10 and 11 show a fifth embodiment corresponding to claim 5 of the present invention, in which the vibration modes on the respective surfaces of the side walls 4, 5 and the bottom wall 3 are shown. In-phase belly W
And the antinode Z are connected by the reinforcing plate 18, and the damping material 19 is interposed at the antiphase antinode position X. In this configuration, since the damping material 19 is interposed when the side walls 4, 5 and the bottom wall 3 resonate during operation, the damping material 1 has a relative displacement at the antiphase antinode of the vibration mode.
It is utilized that 9 expands and contracts, internal friction occurs and a vibration damping action works. Therefore, the vibration and noise of the entire rotating machine can be reduced.

(Sixth Embodiment) FIG. 12 shows a sixth embodiment corresponding to claim 6 of the present invention. Among the plurality of axial ribs, the bottom wall 3 located below the stator core is shown. This shows that the damping member 19 is interposed at the corner of the connecting portion of the axial ribs. Since the relative displacement between the rib and the bottom wall 3 occurs as shown in FIG. 13, the damping member 19 expands and contracts. Since the fact that internal friction is generated and the vibration damping action works is utilized, the vibration and noise of the rotating machine as a whole can be reduced.

(Seventh Embodiment) FIG. 14 shows a seventh embodiment corresponding to claim 7 of the present invention.
By using elastic rubber or epoxy resin as the material of 9, the internal damping is larger than that of the metal material of steel, so that the vibration damping can be increased. Therefore, resonance due to electromagnetic vibration can be almost prevented. As a result, vibration damping performance can be improved, and thus operating noise can be reduced.

[0039]

Since the rotating electric machine of the present invention is constructed as described above, it has the following effects. According to the invention of claim 1, with respect to the surfaces of the side wall and the bottom wall surrounded by the connecting wall and the connecting wall outer wall of the stator frame main body, the number of vibration mode nodes m at each center of the antinode of the vibration mode, Since weights that are ⅕ or more of the weight of each block divided by n are attached, even if the natural frequencies of the side wall and bottom wall and the frequency of the electromagnetic excitation force match or come close to each other, the vibration of the antinode By fixing the weight to the part where the amplitude is large, the natural frequency can be reduced and resonance can be avoided, so that the noise reduction effect can be obtained.

According to the second aspect of the invention, the weight may be attached by a screw hole, welding, a through hole, or a magnetic adhesive fixing method. Therefore, the attachment can be simplified and the manufacturability is improved. Can be made.

According to the third aspect of the present invention, by attaching the weight to the maximum displacement point of the antinode of the vibration mode by fixing the point contact, the surface and the line contact are fixed, and the rigidity against the side wall and the side wall is improved. As the weight increases, the natural frequency becomes higher, but the point contact of the weight does not increase the rigidity, and the weight of the weight effectively acts to reduce the natural frequency, avoiding resonance. Noise reduction effect can be obtained.

According to the invention of claim 4, the node of the vibration mode of the bottom wall, or the node of the vibration mode of the side wall and the antinode of the vibration mode of the bottom wall are connected by a reinforcing material. Since the amplitude of the antinode is large, by fixing the connecting member to the node of the vibration mode of the small amplitude, the amplitude of the antinode of the vibration mode is suppressed, the vibration is reduced, and the vibration and noise can also be reduced. .

According to the fifth aspect of the present invention, the antiphase antinodes and antinodes of the vibration modes on the respective surfaces of the side wall and the bottom wall are connected by the reinforcing plate, and the damping material is interposed at the antiphase antinode portions. In this case, since the damping material is interposed when the side wall and the bottom wall are in operation during operation, there is relative displacement at the anti-phase anti-node and the anti-phase anti-node of the vibration mode. The vibration and noise can also be reduced by utilizing the fact that the expansion and contraction causes internal friction and the vibration damping action works.

According to the sixth aspect of the invention, among the plurality of axial ribs, the damping material is interposed at the corners of the connecting portions of the three axial ribs of the bottom wall located below the stator core. Vibration and noise can also be reduced by utilizing the fact that relative displacement between the rib and the bottom wall occurs, the damping material expands and contracts, internal friction occurs, and a vibration damping action works.

According to the seventh aspect of the invention, the damping material is made of elastic rubber or epoxy resin, so that the vibration damping can be increased and the operating noise can be reduced even if resonance occurs due to electromagnetic vibration. .

[Brief description of drawings]

FIG. 1 is a perspective view of a stator frame showing a first embodiment of the present invention,

FIG. 2 is a vertical cross-sectional view taken along the line III-III in FIG.

FIG. 3 is a perspective view of a stator frame for explaining the vibration mode section of FIG. 1;

FIG. 4 is a diagram showing noise characteristics and natural frequencies,

FIG. 5 is a diagram showing noise characteristics,

FIG. 6 is a diagram showing a second embodiment of the present invention,

FIG. 7 is a diagram showing a third embodiment of the present invention,

FIG. 8 is a diagram showing a fourth embodiment of the present invention,

FIG. 9 is a diagram showing a vibration mode of a stator frame,

FIG. 10 is a diagram showing a fifth embodiment of the present invention,

FIG. 11 is a diagram showing a vibration mode of a stator frame,

FIG. 12 is a view corresponding to FIG. 2, showing a sixth embodiment of the present invention,

FIG. 13 is a diagram showing a vibration mode of a stator frame,

FIG. 14 is a view corresponding to FIG. 2 showing a seventh embodiment of the present invention,

FIG. 15 is a view corresponding to FIG. 1 showing a conventional configuration,

FIG. 16 is a top view of a stator frame showing a conventional configuration,

FIG. 17 is a vertical cross-sectional view taken along line KK of FIG.

FIG. 18 is a vertical cross-sectional view taken along the line LL in FIG.

FIG. 19 is a diagram for explaining a natural vibration mode and a natural vibration spectrum;

FIG. 20 is a diagram illustrating a vibration mode,

FIG. 21 is a vertical cross-sectional view showing a different conventional configuration.

[Explanation of symbols]

1 ... Stator frame, 2 ... Stator frame body,
3, 13 ... Bottom wall, 4, 5, 15 ...
Side walls, 6, 7 ... Connecting wall, 6a, 7a ... Outer wall, 6b, 7b ... Inner wall, 6c, 6d, 7c, 7d ... Connecting axial ribs, 8 ... Stator core, 9a ...
9h ... axial rib, 10 ... annular rib, 1
1a to 11d ... Reinforcing ribs, 12 ... Stator body,
14a, b ... Supporting base, 16 ... Weight,
17 ... Connecting material, 18 ... Reinforcing plate, 1
9 ... Damping material.

Claims (7)

[Claims] 1. A bottom wall of a stator frame main body, side walls erected on both side edges of the bottom wall in a radial direction, a connecting wall connecting the side walls and a connecting wall outer wall, and the stator frame main body. A stator frame formed by arranging a plurality of axial ribs extending in the axial direction in a cylindrical shape, and a stator core formed by stacking steel plates and fitted and supported inside the axial ribs. In the stator of the rotating electric machine provided, the number of nodes m parallel to two sides of a rectangular plane at the center of each antinode position of the vibration mode with respect to the surfaces of the side wall and the bottom wall,
1/5 of the weight of each block divided in n vibration modes
A stator for a rotating electric machine, which is equipped with the above weights. 2. The stator of a rotating electric machine according to claim 1, wherein the weight is attached to the side wall and the bottom wall by screw holes, welding, through holes, magnets or adhesive fixing. 3. The stator of a rotary electric machine according to claim 1, wherein the weight is attached by fixed point contact at the maximum displacement point of the antinode of the vibration mode. 4. A rotary electric machine, wherein the node of the vibration mode of the side wall and the node of the vibration mode of the bottom wall, or the node of the vibration mode of the side wall and the node of the vibration mode of the bottom wall are connected by a reinforcing material. Stator. 5. A portion where an antinode and an antinode of the same vibration mode of the side wall and the bottom wall are connected by a reinforcing plate, and an antinode of antiphase of the vibration mode between the antinode and antinode of the same vibration mode is located. A stator of a rotating electric machine, characterized in that a damping material is interposed in the stator. 6. A damping material is interposed between the axial ribs located below the stator core among the plurality of axial ribs, the bottom wall and the stator core. Stator of rotating electric machine. 7. The stator of a rotating electric machine according to claim 5, wherein the damping material is elastic rubber or epoxy resin.