JPH09117119A - Squirrel-cage rotor and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure a rotor bar and an end ring rigidly by a simple method. SOLUTION: A rotor bar 14 is inserted into the slot 11 of a rotor core 13 while projecting 14a outward from the rotor core 13. While rotating the rotor core 13 and the rotor bar 14, a die 10 is abutted against the projecting part 14a thus bending the projecting part 14a along the outer surface of rotor core 13. An independent ring is secured, as an end ring, to the bent part by welding, ultrasonic welding, frictional press fit, build up welding, adhesion, brazing, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a squirrel-cage rotor for an induction motor and a method for manufacturing the same, and particularly, not only aluminum and aluminum alloy but also copper and copper alloy are used as the conductor material of the rotor bar and the end ring. The present invention relates to a squirrel cage rotor and a manufacturing method thereof.

[0002]

2. Description of the Related Art Generally, a squirrel-cage rotor of an induction motor is
As shown in FIGS. 13 and 14, the rotor core 3 is formed by laminating a plurality of thin plates such as silicon steel plates punched out of the slots 1 and the shaft holes 2. The slot 1
Is a groove for inserting the rotor bar 4 made of a conductive material, that is, a conductor, and is formed in a large number in the circumferential direction of the rotor core 3. On the other hand, the shaft hole 2 is for inserting a rotary shaft (not shown) to support the rotor and transfer power.

The rotor core 3 as described above is a magnetic circuit, and the rotor bar 4 is inserted into each slot 1.
Both ends thereof are short-circuited by an annular end ring 5 to form a conductor portion, which constitutes a circuit for passing a current. By the way, as a method of inserting the rotor bar 4 into the slot 1, conventionally, a casting method or a driving method has been adopted. As an example of the casting method, a die casting method or a centrifugal casting method is used, and as shown in FIG. 15, the rotor bar 4 and the end ring 5 are integrally cast. On the other hand, in the case of the driving method, as shown in FIG. 16, after the rotor bar 4 is driven into the slot 1, separate end rings 5 are joined to both ends of the rotor bar 4 via the joining portions 6. ing. This joining is performed by butt brazing using silver brazing or butt arc welding.

[0004]

Among the conventional methods for manufacturing a squirrel-cage rotor, the former method by the casting method is, for example, in the aluminum casting method by the die casting method or the centrifugal casting method, in the inside of the conductor at the time of casting or cooling. Air, etc. enter, rotor bar 4
There is also a problem that a small cavity is likely to occur in the end ring 5.

It is known that a high-efficiency induction motor can be obtained by using copper or a copper alloy having a low electric resistance as the conductor material, but the melting temperature of aluminum (about 600 ° C.) Since the melting temperature of copper and copper alloys is as high as about 1100 ° C, there are many defects during casting,
Even if a heat-resistant material is used for the die casting jig, its consumption is severe and the cost becomes high. Therefore, the rotor bar 4
Also, it is difficult to cast the end ring 5 using a material other than aluminum having a relatively low melting temperature.

On the other hand, the latter by the driving method is
Copper and a copper alloy can be used as the material of the rotor bar 4 and the end ring 5, but it is necessary to integrate the rotor bar 4 and the end ring 5, which are machined separately as separate bodies, through the joint portion 6. Since the rotor bar 4 and the end ring 5 are conventionally integrated by butt-joining, there is a problem that the joining portion lacks reliability not only in brazing but also in arc welding. .

Therefore, in some cases, when brazing or arc welding is performed, a method of forming a groove portion for inserting the rotor bar 4 into the end ring 5 by machining is proposed, but due to variation in dimensional tolerance of the groove portion. There is a problem that the bondability is greatly affected by the size of the clearance. In particular, when brazing is performed in a vacuum or in a gas atmosphere, the appropriate clearance is 0.1 mm or less, but when the number of rotor bars 4 is several tens, such as a cage rotor, It is extremely difficult to process the groove portion with that accuracy. Further, even if this is possible, there is a problem that the processing man-hours increase and the product cost increases because of that. On the other hand, in the case of arc welding, higher accuracy than in the case of brazing is not required, but groove processing for welding is required in addition to groove processing, which increases the processing man-hour and welds the welding groove. Therefore, there is a problem that the number of welding steps also increases.

Therefore, an object of the present invention is to use not only aluminum and aluminum alloys but also copper and copper alloys as the conductor material of the rotor bar and the end ring, and moreover, it is easy to manufacture and obtains a large bonding strength. An object of the present invention is to provide a squirrel cage rotor and a manufacturing method thereof. Another object of the present invention is to provide a squirrel-cage rotor and a method for manufacturing the squirrel-cage rotor, which can reduce costs.

[0009]

To achieve the above object, the present invention provides a rotor core formed by laminating thin plates, a rotor bar inserted into a plurality of slots formed in the peripheral edge of the rotor core, and a rotor bar. In a squirrel-cage rotor having end rings respectively provided at both end portions of the rotor bar, both end portions of the rotor bar are projected outward from the rotor core, and the projecting portions are bent along the outer surface of the rotor core. The end ring is characterized in that a separate ring is integrally joined to the bent portion. By joining the ring to the bent portion of the rotor bar, the joining area is increased, and the joining strength between the rotor bar and the ring is increased, so that the reliability can be improved. Further, since it is only necessary to bend the protruding portion of the rotor bar from the rotor core, it is possible to easily manufacture the rotor bar. Further, since it is not a casting method, it is possible to use copper and copper alloys as materials for the rotor bar and the ring.

The present invention also includes a rotor core formed by laminating thin plates, a rotor bar inserted into a plurality of slots formed in the peripheral portion of the rotor core, and end rings provided at both ends of the rotor bar. In the basket-type rotor provided, both end portions of the rotor bar are projected outward from the rotor core, and the projecting portions are bent along the outer surface of the rotor core. It is characterized in that they are connected to form an end ring. As a result, it is not necessary to manufacture the ring by machining or the like, and the cost can be reduced.

According to the present invention, the rotor core is constructed by laminating thin plates having a plurality of slots on the peripheral edge thereof.
A rotor bar is inserted into each slot of the rotor core, and end portions of the rotor bar are respectively provided in the cage rotor in the method of manufacturing a cage rotor, and both ends of the rotor bar are projected outward from the rotor core. It is characterized in that each protruding portion is bent along the outer surface of the rotor core, and then a separate ring is integrally joined to these bent portions to form an end ring. By joining the ring to the bent portion of the rotor bar, it is possible to increase the joining area and increase the joining strength. Further, since a simple operation of bending the end portion of the rotor bar is sufficient, the manufacturing is easy, and copper and copper alloy can be used as the material of the rotor bar and the ring.

The present invention is also characterized in that the rings are joined together by welding. Since this joining method is a fusion welding that has a proven record in the past, an end ring with high joining reliability can be obtained. The present invention is also characterized in that the rings are integrally joined by friction welding. Since this friction welding uses mutual frictional heat between the rotor bar and the ring, it can be joined in a short time, the heat effect on the squirrel cage rotor is small, and the strength reduction of the rotor bar and the end ring can be suppressed. Become.

According to the present invention, further, thin plates having a plurality of slots on the periphery are laminated to form a rotor core, the rotor bar is inserted into each slot of the rotor core, and the end rings are provided at both ends of the rotor bar. In the method for manufacturing a squirrel cage rotor, both end portions of each rotor bar are projected outward from the rotor core, and each protruding portion is bent along the outer surface of the rotor core, and then each of these bent portions is overlaid. It is characterized in that the end rings are connected to each other by welding. As a result, it is not necessary to separately manufacture the ring by machining or the like, and the manufacturing cost can be reduced.

[0014]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described below with reference to the drawings. 1 to 4 show a squirrel cage rotor according to a first embodiment of the present invention. This squirrel cage rotor has a peripheral portion as shown in FIGS. 1 (a) and 1 (b). A rotor core 13 having a large number of slots 11 and a thin plate such as a quartz steel plate having a shaft hole 12 at the center is laminated, and each slot 11 of the rotor core 13 is provided with copper and copper alloy. Alternatively, the rotor bar 14 made of highly conductive material such as aluminum and aluminum alloy is inserted by a driving method.

Both ends of each rotor bar 14 are shown in FIG.
As shown in FIG. 2B, the protrusions 14a project outward from the rotor core 13. The protrusions 14a are brought into contact with the die 10 while the rotor core 13 is being rotated as shown in FIG. Along the circumference of the bent portion 14 as shown in FIG.
b is configured.

As shown in FIGS. 3 and 4, a material having high conductivity such as copper and copper alloys or aluminum and aluminum alloys is used on the inner peripheral side of these bent portions 14b to separate them by machining or the like. A ring-shaped ring 16 formed on the outer peripheral portion of the ring 16 is fillet-welded by fusion welding such as arc welding as shown in FIG. It is adapted to be integrated with each bent portion 14b through. And this ring 1
The end ring 15 is configured by 6 and the bent portions 14b.

Next, the operation of this embodiment will be described. In manufacturing the squirrel cage rotor, first, thin plates are laminated to form the rotor core 13, and the rotor bar 14 is inserted into each slot 11 of the rotor core 13 by a driving method. Figure 1 (b) shows this state.
Both ends of each rotor bar 14 protrude outward from the rotor core 13 as protrusions 14a.

Next, while rotating the rotor core 13, the die 10 is brought into contact with each of the protrusions 14a. Then, each protruding portion 14a is bent in the circumferential direction along the outer surface of the rotor core 13 to form a bent portion 14b as shown in FIG. Therefore, on the inner peripheral side of these bent portions 14b, an annular ring 16 that is manufactured in advance by machining or the like is used.
And the fillet welding is performed by fusion welding such as arc welding, and the ring 16 and each bent portion 14b are integrated via the welded portion 17 to form the end ring 15.

Since the ring 16 is welded to the bent portion 14b, the joint area can be increased and a large joint strength can be obtained. Further, since the joining method is fusion welding, which has a proven record in the past, high reliability can be obtained.

FIG. 5 shows a second embodiment of the present invention. Instead of the welded portion 17 in the first embodiment, the ring 16 and the bent portion 14b are provided with a friction welding portion 27. The end ring 15 is constructed by joining. That is, as shown in FIG. 5, the ring 16 is dimensioned so that it can be arranged on the outer surface side of each bent portion 14b, and the ring 16 is rotated while the rotor core 13 and the rotor bar 14 are stationary. By doing so, the ring 16 and each bent portion 14 b are integrally joined via the friction welding portion 27 to form the end ring 15.

By joining the ring 16 to the bent portion 14b, a large joint surface can be secured, and since the bent portion 14b has a large surface area, the rotor bar 14 does not buckle during friction welding. . Also,
Friction welding uses frictional heat between the members, so that the members can be joined in a short time, the heat influence on the rotor core 13, the rotor bar 14, and the ring 16 can be reduced, and the strength reduction of the members can be suppressed as much as possible. FIG. 6 shows a third embodiment of the present invention, in which the welded portion 1 of the first embodiment is used.
Instead of 7, the ring 16 and the bent portion 14b are joined via the ultrasonic welding portion 37 to form the end ring 15.

That is, as shown in FIG. 6, the ring 16 is dimensioned so that it can be arranged on the outer surface side of each bent portion 14b, and the ring 16 is ultrasonically welded from its outer surface side. Ultrasonic energy from the power source 30 is applied via the vibrator 31. FIG.
In the figure, reference numeral 32 indicates the amplitude direction of the vibrator 31.

In this ultrasonic welding, for example, a high cycle vibration of about 20 KHz and an amplitude of several tens of microns is applied to the ring 16
Is applied to the joint surface between the bent portion 14b and the bent portion 14b, whereby the joint surface is activated to facilitate interatomic bonding of metal between the members, and the ring 16 and each bent portion 14b are ultrasonically welded. It can be firmly joined via the portion 37.

However, since the ultrasonic welding is room temperature bonding, there is no reduction in the strength of the material due to heat, and high reliability can be obtained.

FIG. 7 shows a fourth embodiment of the present invention. Instead of the welded portion 17 in the first embodiment, the ring 16 and the bent portion 14b are replaced with the overlay welded portion 47. The end ring 15 is formed by joining the end rings 15 with each other. That is, the ring 16 has each bent portion 14b.
The groove 16a is formed at the outer peripheral portion of the groove 16a. And ring 16
Also, the powder supply device 4 is provided on the outer surface side of each bent portion 14b.
The build-up material from 0 is supplied through the powder supply nozzle 41, and the build-up material is melted by the plasma arc 43 from the plasma build-up welding nozzle 42, so that the ring 16 and each bent portion 14b are separated. It is adapted to be integrally joined via the overlay welding portion 47. Since this overlay welding uses high-density plasma as a heat source, the heat effect on the material of the ring 16 and the rotor bar 14 is lower than that of the heat source of the arc, and the strength of the material is reduced by the heat. Can be suppressed as much as possible.

FIG. 8 shows a fifth embodiment of the present invention, in which the ring 16 in the fourth embodiment is omitted, and the bent portions 14b are connected to each other by a weld overlay 47. Then, the end ring 15 is configured. That is, the build-up material from the powder supply device 40 is supplied to the outer surface side of each bent portion 14b through the powder supply nozzle 41, and the build-up material is a plasma build-up welding nozzle. It is melted by the plasma arc 43 from 42, and the respective bent portions 14b are connected to each other through the overlay welding portion 47 to form the end ring 15. In this case, however, the ring 16 is unnecessary, so that the manufacturing cost can be reduced.

FIG. 9 shows a sixth embodiment of the present invention, in which the ring 16 and the bent portion 14b are joined via an adhesive portion 57 instead of the weld portion 17 in the first embodiment. Then, the end ring 15 is configured. That is, as shown in FIG. 9, the ring 16 is dimensioned so as to be arranged on the outer surface side of each bent portion 14b, and the ring 16 and each bent portion 14b are arranged.
An adhesive agent is interposed between and. Then, the ring 16 and each bent portion 14b are heated by the adhesive between them at around 200 ° C.
The end ring 18 is configured by being integrally joined via the. Then, the bonding by the adhesive portion 57 is
Since heating at around 200 ° C. is sufficient, strength reduction due to heat of the material can be significantly suppressed as compared with fusion welding such as arc welding.

FIG. 10 shows a seventh embodiment of the present invention, in which the ring width of the ring 16 in the sixth embodiment is enlarged so that the adhesive portion 57 can be enlarged to the rotor core 13. It is a thing.

That is, as shown in FIG. 10, the ring 16 has a wide annular shape that can cover from the outer edge of the rotor core 13 to the inner side of the inner end of the bent portion 14b, and its inner surface. The recessed portion 16b corresponding to each bent portion 14b or the ring groove in which each bent portion 14b is continuous in the circumferential direction is provided in the. Then, the ring 1 including the recess 16b or the ring groove
The inner surface of 6 and the outer surfaces of the bent portions 14b and the rotor core 13 are integrally joined via the adhesive portion 57. However, in this case, the area of the adhesive portion 57 is increased as compared with the case of the sixth embodiment, and the bonding strength can be increased accordingly.

FIG. 11 shows an eighth embodiment of the present invention. Instead of the welded portion 17 in the first embodiment, the ring 16 and the bent portion 14b are brazed to each other.
The end ring 15 is configured by being integrally joined via the. That is, as shown in FIG. 11, the ring 16 is dimensioned so that it can be arranged on the outer surface side of each bent portion 14 b, and the ring 16 and each bent portion 14 b are brazed to each other. It is designed to be integrally joined via. The brazing part 67 is formed by a brazing method such as placement brazing in a vacuum, an inert gas atmosphere or an atmosphere, or a brazing method by burner heating or carbon heating. In either case, sufficient bonding strength can be obtained.

The brazing temperature is the rotor core 1
3 and the melting point of the rotor bar 14 are lower than the melting points of the rotor 3 and the rotor bar 14, there is no fear that the strength of these will decrease due to heat, and reliability can be improved.

FIG. 12 shows a ninth embodiment of the present invention, in which the ring width of the ring 16 in the eighth embodiment is enlarged and the area of the brazing portion 67 can be enlarged. It is a thing.

That is, as shown in FIG. 12, the ring 16 has an annular shape wide enough to completely cover each bent portion 14b, and its inner surface corresponds to each bent portion 14b. Recessed portion 16b or each bent portion 14b
Is provided in the circumferential direction so as to be continuous in the circumferential direction. The recess 16b or the ring groove and each bent portion 14b are integrally joined via the brazing portion 67. In this case, however, the area of the brazing portion 67 can be increased more than in the case of the eighth embodiment, and the bonding strength can be improved accordingly. In each of the above-described embodiments, the case where the protruding portions 14a at both ends of each rotor bar 14 are bent in the circumferential direction has been described, but the bending direction does not necessarily have to be the circumferential direction, and for example, the bending direction may be in the radial direction. It may be bent.

[0034]

As described above, according to the present invention, a rotor core formed by laminating thin plates, a rotor bar inserted into a plurality of slots formed in the peripheral portion of the rotor core, and both end portions of the rotor bar are provided. In a squirrel-cage rotor having an end ring provided, both end portions of the rotor bar are projected outward from the rotor core, and the projecting portions are bent along the outer surface of the rotor core, and the end ring is Since the separate ring is integrally joined to the bent portion, the bent portion of the rotor bar can increase the joint area with the ring, thereby increasing the joint strength and improving the reliability. it can. Moreover, since it is only necessary to bend the end portion of the rotor bar, manufacturing is easy. Moreover, since it is not a casting method, copper and copper alloys can be used as the material of the rotor bar and the ring.

The present invention also includes a rotor core formed by stacking thin plates, a rotor bar inserted into a plurality of slots formed in the peripheral portion of the rotor core, and end rings provided at both ends of the rotor bar. In a basket-type rotor provided, both end portions of the rotor bar are projected outward from the rotor core, the projecting portions are bent along the outer surface of the rotor core, and the bent portions are interconnected by overlay welding. Since the end ring is configured by doing so, it is not necessary to pre-manufacture the ring by machining or the like, and the cost can be reduced.

According to the present invention, the rotor core is constructed by laminating thin plates having a plurality of slots on the peripheral edge,
A rotor bar is inserted into each slot of the rotor core, and end portions of the rotor bar are respectively provided in the cage rotor in the method of manufacturing a cage rotor, and both ends of the rotor bar are projected outward from the rotor core. Since each projecting part is bent along the outer surface of the rotor core, and a separate ring is integrally joined to these bent parts to form an end ring, the joint area is defined by the bent parts of the rotor bar. Can be increased and the bonding strength can be increased. Further, since the simple work of bending the end portion of the rotor bar is sufficient, the manufacturing is easy, and since it is not a casting method, copper and copper alloy can be used as the material of the rotor bar and the ring.

Further, according to the present invention, since the rings are integrally joined by welding, it is possible to obtain an end ring having high joining reliability. Further, according to the present invention, since the rings are integrally joined by friction welding, the rings can be joined in a short time and the reduction in strength due to heat of the material can be suppressed. The present invention further constitutes a rotor core by laminating thin plates having a plurality of slots on the peripheral edge,
A rotor bar is inserted into each slot of this rotor core, and end rings are provided at both ends of the rotor bar. In the method for manufacturing a cage rotor, both ends of the rotor bar are projected outward from the rotor core and Since the parts are bent along the outer surface of the rotor core and then these bent parts are connected to each other by overlay welding to form the end ring, it is not necessary to separately manufacture the ring by machining or the like. , The manufacturing cost can be reduced.

[Brief description of the drawings]

FIG. 1A is a configuration diagram of a rotor core of a squirrel cage rotor according to a first embodiment of the present invention as seen from an axial direction, and FIG.
FIG. 3 is an explanatory view showing a state where a rotor bar is inserted in a rotor core.

FIG. 2 is an explanatory view showing a method of bending an end portion of a rotor bar.

FIG. 3 is an explanatory view showing a state in which a separate ring is attached to the bent portion at the end of the rotor bar.

FIG. 4 is an explanatory view showing a state in which a ring and a bent portion are integrally joined by fillet welding.

FIG. 5 is a view corresponding to FIG. 4, showing a second embodiment of the present invention.

FIG. 6 is a view corresponding to FIG. 4, showing a third embodiment of the present invention.

FIG. 7 is a view corresponding to FIG. 4, showing a fourth embodiment of the present invention.

FIG. 8 is a view corresponding to FIG. 4 showing a fifth embodiment of the present invention.

FIG. 9 is a view corresponding to FIG. 4 showing a sixth embodiment of the present invention.

FIG. 10 is a view corresponding to FIG. 4 showing a seventh embodiment of the present invention.

FIG. 11 is a view corresponding to FIG. 4 showing an eighth embodiment of the present invention.

FIG. 12 is a view corresponding to FIG. 4 showing a ninth embodiment of the present invention.

FIG. 13 is a configuration diagram of a rotor core of a conventional squirrel cage rotor as viewed from the axial direction.

FIG. 14 is a side view of FIG. 13;

FIG. 15 is an explanatory diagram showing a method of manufacturing a rotor bar and an end ring by a casting method.

FIG. 16 is an explanatory diagram showing a method of inserting a rotor bar into a slot by a driving method and then joining a separate end ring to the end portion thereof.

[Explanation of symbols]

 11 slot 12 shaft hole 13 rotor core 14 rotor bar 14a protruding part 14b bent part 15 end ring 16 ring 16a groove 16b recessed part 17 welded part 27 friction welded part 37 ultrasonic welded part 47 overlay welded part 57 adhesive part 67 brazed part

Claims (6)

[Claims] 1. A rotor core formed by laminating thin plates,
In a squirrel-cage rotor including a rotor bar inserted into a plurality of slots formed in the peripheral portion of the rotor core, and end rings respectively provided at both ends of the rotor bar, the rotor bar has its both ends separated from the rotor core. While projecting in one direction, this projecting portion is bent along the outer surface of the rotor core, and the end ring is
A squirrel-cage rotor characterized in that a separate ring is integrally joined to the bent portion. 2. A rotor core formed by laminating thin plates,
In a squirrel-cage rotor including a rotor bar inserted into a plurality of slots formed in the peripheral portion of the rotor core, and end rings respectively provided at both ends of the rotor bar, the rotor bar has its both ends separated from the rotor core. While projecting in one direction, this projecting portion is bent along the outer surface of the rotor core, and the end ring is
A squirrel-cage rotor characterized in that the bent portions are connected to each other by overlay welding. 3. A squirrel cage rotation in which thin plates having a plurality of slots on the periphery are laminated to form a rotor core, rotor bars are inserted into the slots of the rotor core, and end rings are provided at both ends of the rotor bar. In the manufacturing method of the child, the both ends of each rotor bar,
An end ring is formed by projecting outwardly from the rotor core, bending each projecting portion along the outer surface of the rotor core, and then separately joining a separate ring to these bent portions. Method of manufacturing a cage rotor. 4. The method of manufacturing a squirrel cage rotor according to claim 3, wherein the rings are integrally joined by welding. 5. The method of manufacturing a squirrel cage rotor according to claim 3, wherein the rings are integrally joined by friction welding. 6. A squirrel cage rotation in which a thin plate having a plurality of slots is laminated on the peripheral edge to form a rotor core, and a rotor bar is inserted into each slot of the rotor core, and end rings are provided at both ends of the rotor bar. In the manufacturing method of the child, the both ends of each rotor bar,
A car characterized by protruding outward from the rotor core, bending each protruding portion along the outer surface of the rotor core, and then connecting these bent portions to each other by overlay welding to form an end ring. Rotor manufacturing method.