JP3466864B2 - Rotor of cage induction motor and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a squirrel-cage induction motor rotor used in compressors, blowers and the like, and a method for manufacturing the rotor.

[0002]

2. Description of the Related Art In recent years, compressors and blowers are required to have high efficiency and low noise for the purpose of energy saving. Therefore, various design methods and manufacturing methods are used to obtain higher efficiency and low noise. Therefore, the contents are becoming more precise.

FIG. 9 shows a rotor and a stator of a conventional squirrel cage induction motor. In FIG. 9, 1 is a radial cross section of a stator core configured by stacking a large number, and 2
Is a slot of the stator and 3 is a tooth of the stator. Also, 4
Is a radial cross section of a rotor core formed by stacking a large number of layers, 5 is a rotor slot, and 6 is a rotor tooth.

Twenty-four stator slots 2 are arranged at equal intervals on the inner circumference of the stator core 1, and coils are inserted inside the stator slots 2. By applying a three-phase voltage to the coils, Generates a rotating magnetic field with two poles. The rotor slots 5 are arranged on the outer periphery of the rotor core 4 at equal intervals, and secondary conductor bars are formed therein. Generally, the number of slots in the rotor is from 0.6 times the number of slots in the stator to 1.
About 5 times is often used, and if the number of slots in the stator is 24, the number of slots in the rotor is generally 14 to 36.

FIG. 10 shows the laminated rotor core 4 shown in FIG. 9 in which a secondary conductor is formed, which is widely manufactured by integrally molding the bar and the end ring 11 by aluminum die casting. Are known.

[0006]

Since the rotor of the conventional squirrel-cage induction motor is constructed as described above, the frequency due to the combination of the number of slots of the rotor and the stator, that is, the frequency according to the common multiple of the number of slots is Electromagnetic noise is large due to the low frequency, and the efficiency is low due to the small number of rotor slots. The efficiency is considerably low at a commonly used rotor slot number of about 0.6 to 1.5 times the number of stator slots, and at less than 2 times, the efficiency is not sufficient. If the number of slots is simply increased, aluminum leaks from the gap between the electromagnetic steel plates due to pressure conditions or the like when die casting is performed, which causes a bridge and increases loss. Also, as a means of increasing efficiency, copper having good conductivity may be used for the secondary conductor.
The copper die-cast method requires expensive equipment.

As prior art as publications, Japanese Utility Model Publication No. 60-132152 and Japanese Utility Model Publication No. 01-147647.
JP-A-55-34831, JP-A-57-
Although there are 80250 and Japanese Patent Laid-Open No. 02-206347, these cannot solve the above problems.

The present invention has been made to solve the above problems, and an object thereof is to obtain a highly efficient rotor of a squirrel-cage induction motor with reduced loss. The purpose is to realize noise reduction.

[0009]

In the squirrel-cage induction motor rotor of the first invention, a squirrel-cage having a stator for generating a rotating magnetic field and a rotor driven by the generated magnetic field of the stator. In the induction motor, the number of slots of the rotor is twice or more the number of slots of the stator, and
Laminating those in which the adhesive is applied to the surface of the electromagnetic steel sheets of the rotor core formed by laminating many magnetic steel sheets, laminated electrical steel
The plate is die-cast to be integrally formed as a rotor .

In the squirrel cage induction motor rotor manufacturing method of the second invention, a stator for generating a rotating magnetic field and a rotor driven by the stator generated magnetic field are provided.
In the method of manufacturing a rotor of a squirrel cage induction motor, wherein the number of slots of the rotor is set to be twice or more the number of slots of the stator, in manufacturing a rotor core produced by punching an electromagnetic steel plate, slot unplug hit <br/> Chi in several portions, by laminating magnetic steel sheets slot punched,
Die-cast the laminated electromagnetic steel sheets to obtain the rotor.
It is obtained as that.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. The first embodiment of the present invention will be described below with reference to FIGS. First Embodiment FIG. 1 shows a rotor and a stator of a squirrel cage induction motor according to a first embodiment of the present invention.
In FIG. 1, 1 is a radial cross section of a stator core formed by stacking a large number of layers, 2 is a slot of a stator, 3 is teeth of a stator, 4 is a radial direction of a rotor core that is formed by stacking a plurality of layers A cross section, 5 is a rotor slot, and 6 is a rotor tooth.

In FIG. 1, a stator core 1 is constructed by laminating a large number of punched electromagnetic steel sheets. The stator slot 2 has a round bottom shape of a semi-closed slot, and the stator core 1
Are evenly spaced on the inner circumference. A coil is wound inside the stator slot 2 and a two-pole rotating magnetic field is generated by applying a three-phase AC voltage and passing a current. The stator teeth 3 have a constant width in the radial direction.

The rotor core 4 is formed by laminating a large number of electromagnetic steel plates, like the stator core 1. The rotor slots 5 are arranged at equal intervals on the outer circumference of the rotor core 4, and have closed slots, a round bottom shape, and an aluminum bar formed inside. To form. Rotor teeth 6
Sets the size of the round bottom of the rotor slot 6 so as to have a constant width in the radial direction like the stator tooth 3.

Now, the flow of a general method for manufacturing a rotor of a squirrel cage induction motor will be described. The electromagnetic steel plates are punched into a rotor shape, and a large number of punched electromagnetic steel plates are laminated to form a rotor core 4. The thickness of one magnetic steel sheet is generally 0.35 mm or 0.5 mm.

Next, the rotor core is heat-treated, set in a die-casting mold, and aluminum melted at high temperature is poured into the mold to integrally form a secondary conductor consisting of a bar and an end ring. For large induction motors, there is also a method in which the bar is inserted into the rotor slot 5 and then welded to the end ring.

FIG. 2 is a curve diagram showing the efficiency characteristic of the electric motor when the load torque is constant, and the horizontal axis is the ratio of the number of slots of the rotor to the number of slots of the stator (hereinafter referred to as the slot ratio). Inverter drives the motor at 60Hz
It is the characteristic at the rated load when it is operated at, and the slip at that time is about 3.0 to 3.5%. The size of the round bottom is changed according to the number of slots of the rotor, but the shape of the end ring is constant regardless of the number of slots, and the shape and configuration of the stator are the same regardless of the number of slots of the rotor.

It can be seen from FIG. 2 that the efficiency is increased by increasing the number of slots in the rotor and increasing the slot ratio. In particular, when the slot ratio is less than 2.0, the change is rapid because it is in the low efficiency region, but when the slot ratio is 2.0 or more, the efficiency is sufficiently increased and the change is moderate.

FIG. 3 shows the results of comparison of the characteristics of an electric motor using a rotor with a slot ratio of 2.5 and a conventional electric motor using a rotor with a slot ratio of 1.25. In addition,
The number of slots of the stator is 24, and the number of slots of the rotor is 30 with respect to the number of slots (slot ratio 1.25).
To 60 (slot ratio 2.50). The outer diameter of the rotor is 52 mm, the width of the rotor teeth 6 is 1.95 mm when the slot ratio is 1.25, and 0.96 mm when the slot ratio is 2.50.

In FIG. 3, it can be seen that increasing the slot ratio reduces the current, reduces the input, and improves the efficiency. Also, it can be seen that the stalling torque increases as the slot ratio increases. In addition, it is a characteristic comparison at the time of rated load, and is a characteristic when an electric motor is operated at 60 Hz by an inverter.

As described above, by increasing the number of slots in the rotor, it is possible to obtain a highly efficient rotor for a squirrel-cage induction motor with reduced loss. Further, by increasing the number of slots of the rotor, it is possible to reduce the electromagnetic noise generated from the combination of the numbers of slots.

In this embodiment, the three-phase / two-pole structure has been described, but a single-phase structure may be used, and the same effect can be obtained with any number of poles. Also, the rotor slot may be opened.

Embodiment 2. The second embodiment of the present invention will be described with reference to FIG. FIG. 4 shows a method for manufacturing a rotor of a squirrel-cage induction motor according to Embodiment 2 of the present invention. When punching an electromagnetic steel sheet into a rotor shape by a punch die, the rotor slot portion is moved several times. It is designed to be punched separately.

In FIG. 4, reference numeral 7 denotes an electromagnetic steel plate which is sequentially passed through the punch die, and shows how the punch die punches the steel sheet. The number of rotor slots is 60.

Next, the operation of this embodiment will be described. In STEP 1 of FIG. 4, when 60 slots are generated, first, a quarter of 15 slots,
Punch the inner diameter of the rotor with a punch die. STEP2
1 from the slot punched out in STEP 1
Die punch 15 slots that are offset twice. Further, 15 slots are punched out in STEP 3 and STEP 4, respectively, and the outer diameter portion of the rotor is punched out in STEP 5 to complete one rotor core.

When the number of slots is increased while keeping the outer diameter of the rotor constant, the width of the rotor tooth 6 becomes inevitably narrow.
When a punch die is used to punch a rotor with extremely thin teeth at one time, stress is concentrated on the teeth, and the cross section of the teeth may be deformed into a doglegged shape instead of a square shape. When the rotors whose cross sections are deformed are stacked, a gap is formed in the portion deformed in a dogleg shape. When aluminum die casting is performed here,
Aluminum can leak through the gap and create a bridge.

When the electric motor is operated by using the rotor in which the bridge is generated, the loss increases due to the current flowing through the bridge, and the efficiency decreases.

In this method, since the rotor slot portion is punched in several times when punching with a punch type, by suppressing the gap when stacking as much as possible, aluminum does not leak even if die casting is performed and the bridge Therefore, it is possible to obtain a highly efficient rotor of a squirrel-cage induction motor with reduced loss. Further, by increasing the number of slots of the rotor, it is possible to reduce the electromagnetic noise generated from the combination of the numbers of slots.

However, if the number of slots is increased too much,
Even if the number of punches is divided into several times, the shape of the cross section is deformed, so that the number of slots is also limited. As shown in the first embodiment of the invention, the increase in efficiency becomes slower even if the slot ratio is increased. Therefore, from the viewpoint of characteristics and manufacturing, the slot ratio should be about 1.8 to 2.5. Good.

Embodiment 3. A third embodiment of the present invention will be described with reference to FIG. 5 is a sectional view of the teeth of the rotor core of the squirrel-cage induction motor according to the third embodiment of the present invention, in which the adhesive 9 is applied to the laminated surface of the punched rotor electromagnetic steel sheets shown in FIG. After that, electromagnetic steel sheets are laminated.

In FIG. 5, 8 is an enlarged portion near the slot 5 of the electromagnetic steel plate of the punched rotor, and 9 is an adhesive.

When the number of slots is increased while keeping the outer diameter of the rotor constant, the width of the rotor teeth 6 becomes inevitably narrow.
When attempting to perform aluminum die-casting by laminating electromagnetic steel plates with extremely thin rotor teeth 6, aluminum leaks from the gaps between the laminated electromagnetic steel plates due to the pressure conditions during die casting and the lamination strength of the rotor core 4. Can generate a bridge.

When the electric motor is operated by using the rotor in which the bridge is generated, the loss increases due to the current flowing through the bridge, and the efficiency decreases.

In this method, the electromagnetic steel sheets are adhered and laminated by the adhesive 9 so that aluminum does not leak even when die casting is performed and the formation of bridges is prevented, so that loss is reduced and high efficiency is achieved. It is possible to obtain a rotor of a basket type induction motor. Further, by increasing the number of slots of the rotor, it is possible to reduce the electromagnetic noise generated from the combination of the numbers of slots.

The bonding in this embodiment is for preventing aluminum from leaking through the laminated gap, and a resin or an industrial adhesive may be used as the adhesive.

Fourth Embodiment A fourth embodiment of the present invention will be described with reference to FIG. Figure 6
3 is a sectional view of teeth of a rotor core of a squirrel cage induction motor according to a third embodiment of the present invention, in which a coating of silicon oxide is applied to the inner end surface of the slot 5 of the laminated rotor core 4 shown in FIG. After that, the rotor core 4 is sintered, that is, heated at a high temperature to be integrally formed, and the ceramics 10 and the like are generated on the end surface of the slot 5.

As shown in the third embodiment of the present invention, when aluminum die casting is performed on the rotor core 4 having the rotor teeth 6 having extremely narrow widths, the efficiency may decrease due to the formation of bridges.

In this system, by forming a heat resistant film such as ceramics 10 inside the slot, aluminum does not leak even when aluminum die casting is performed and the formation of bridges is prevented, thus reducing loss. It is possible to obtain a highly efficient rotor of a squirrel-cage induction motor. Further, by increasing the number of slots of the rotor, it is possible to reduce the electromagnetic noise generated from the combination of the numbers of slots.

Embodiment 5. A fifth embodiment of the present invention will be described with reference to FIG. FIG. 7 shows a method of manufacturing the secondary conductor of the rotor of the squirrel cage induction motor according to the fifth embodiment of the present invention.
1 is a secondary conductor end ring, 12 is a secondary conductor bar,
Reference numeral 13 is a structure in which the end ring 11 on one side and the bar 12 are integrated.

As shown in the third embodiment, when the rotor core 4 having the rotor teeth 6 having an extremely small width is subjected to aluminum die casting, the efficiency may decrease due to the formation of bridges.

In this method, the structure 13 in which the end ring 11 on one side and the bar 12 are integrated is inserted into the slot 5 of the rotor core 4, and then welded to the end ring 11 on the other side. No need to do.
Therefore, it is possible to obtain a highly efficient rotor of a squirrel-cage induction motor in which the generation of bridges is prevented and the loss is reduced. Further, by increasing the number of slots of the rotor, it is possible to reduce the electromagnetic noise generated from the combination of the numbers of slots. Furthermore, when considering a copper secondary conductor, it is difficult to realize it by die-casting because the equipment is expensive, but in this method, the bar is inserted into the slot, so the equipment is not expensive and the copper Realization of the next conductor becomes easy. By using copper with good conductivity as the secondary conductor, a more efficient rotor of a squirrel cage induction motor can be obtained.

Sixth Embodiment Embodiment 5 of the present invention will be described with reference to FIG. FIG. 8 shows a method for manufacturing a secondary conductor of a rotor of a squirrel cage induction motor according to Embodiment 5 of the present invention. After inserting the bars 12 of the secondary conductor into the rotor slot 5, The end ring 11 is welded to produce a secondary conductor.

As shown in the third embodiment, when the rotor core 4 having the rotor teeth 6 having an extremely narrow width is subjected to aluminum die casting, the efficiency may decrease due to the formation of bridges.

In this method, since the bar 12 of the secondary conductor is inserted into the slot 5 of the rotor core 4, the end rings 11 on both sides and the inserted bar 12 are welded, so that it is not necessary to perform aluminum die casting. Therefore, it is possible to obtain a highly efficient rotor of a squirrel-cage induction motor that prevents the generation of bridges and reduces losses. Further, by increasing the number of slots of the rotor, it is possible to reduce the electromagnetic noise generated from the combination of the numbers of slots. Furthermore, the fifth embodiment
As shown in, by using copper for the secondary conductor, it is possible to obtain a more efficient rotor of the squirrel-cage induction motor.

[0044]

According to the rotor of the squirrel cage induction motor of the first invention, by increasing the number of slots of the rotor,
It is possible to obtain a highly efficient squirrel-cage induction motor, further reduce noise, and increase the number of slots in the rotor to make the teeth of the rotor thinner and perform aluminum die-casting. , Although aluminum may leak from the gap between the laminated iron cores to form a bridge, the aluminum is surely prevented from leaking by adhesion, the motor efficiency is improved, and energy saving can be realized.

[0045] According to the manufacturing method of the rotor of squirrel-cage induction motor of the second aspect of the invention, have rows in several portions punching slot portion of the electromagnetic steel plates, the electromagnetic steel sheet slot punched
Laminate, die-cast on laminated electromagnetic steel sheets,
Since the rotor is obtained, the gap when electromagnetic steel sheets are laminated is suppressed, and the generation of bridges due to aluminum leakage during aluminum die casting etc. is reliably prevented, improving motor efficiency. Energy saving can be realized.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a rotor and a stator of a squirrel cage induction motor according to Embodiment 1 of the present invention.

FIG. 2 is a curve diagram showing efficiency characteristics of the squirrel cage induction motor according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a characteristic comparison of the squirrel cage induction motors according to the first embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a method of manufacturing a rotor of a squirrel cage induction motor according to a second embodiment of the present invention.

FIG. 5 is an explanatory diagram showing a method of manufacturing a rotor of a squirrel cage induction motor according to Embodiment 3 of the present invention.

FIG. 6 is an explanatory diagram showing a method for manufacturing a rotor of a squirrel cage induction motor according to Embodiment 4 of the present invention.

FIG. 7 is an explanatory diagram showing a method of manufacturing a rotor of a squirrel cage induction motor according to a fifth embodiment of the present invention.

FIG. 8 is an explanatory diagram showing a method for manufacturing a rotor of a squirrel cage induction motor according to a sixth embodiment of the present invention.

FIG. 9 is an explanatory view showing a rotor and a stator of a conventional squirrel cage induction motor.

FIG. 10 is an explanatory diagram showing a rotor of a conventional squirrel cage induction motor.

[Explanation of symbols]

1 stator core, 2 stator slots, 3 stator teeth,
4 rotor core, 5 rotor slots, 6 rotor teeth, 7
Magnetic steel sheet, 8 rotor electromagnetic steel sheet, 9 adhesive, 10
Ceramics, 11 end rings, 12 bars, 13
Bar end ring structure.

Continuation of the front page (56) Reference JP 10-174389 (JP, A) JP 50-122624 (JP, A) JP 2-119558 (JP, A) JP 63-202245 (JP , A) JP-A-8-228460 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H02K 17/20 H02K 15/02 H02K 1/16

Claims (2)

(57) [Claims] 1. In a squirrel-cage induction motor including a stator that generates a rotating magnetic field and a rotor that is driven by the magnetic field generated by the stator, the number of slots of the rotor is twice the number of slots of the stator. In addition to the above, the electromagnetic steel sheets of the rotor core formed by laminating a large number of magnetic steel sheets are coated with an adhesive, and the laminated magnetic steel sheets are die-cast.
A rotor of a squirrel-cage induction motor, which is constructed as a rotor by performing a strike . 2. A stator that generates a rotating magnetic field and a rotor that is driven by the magnetic field generated by the stator are provided, and the number of slots of the rotor is at least twice the number of slots of the stator. in the manufacturing method of the rotor of squirrel-cage induction motor, in producing the rotor core produced by punching electromagnetic steel plates, disconnect hit in several slot portions of the magnetic steel sheets, slot punched electromagnetic Stacking steel plates
, Die-cast the laminated electromagnetic steel sheets, and
A method of manufacturing a squirrel cage induction motor rotor, comprising: