JPH11346462A - Rotor for squirrel-cage induction motor and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a rotor whose electrical conductivity is increased, irregularities are small and which has good operating characteristics, by a method wherein a part which is situated on the outer circumferential side from a prescribed position in the radial direction from the center of the shaft of the rotor formed of one rotor core element plate situated in the end part of a rotor core is bent to the side of an end ring. SOLUTION: A rotor is constituted, in such a way that a rotor core 304 made of flat rolled magnetic steel sheets, a rotor bar 306 and an end ring 312 are assembled integrally to a shaft 305. Then, regarding one or two to three rotor core element plates 308 which are situated in both side ends of the rotor core 304, a part 308a, which is on the outer circumferential side from a prescribed position (a broken-line position) A in the radial direction, is bent into a U-shaped to the side of the end ring 312. After that, an aluminum-based metal is poured to be casted, and the bent part 308a in the rotor core element plates 308 is made to function as a reinforcing plate. As a result, it is possible to obtain a rotor, whose strength drop due to its softening at a high temperature can be suppressed, the electrical conductivity of which is enhanced, and irregularities can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention integrates a rotor conductor including an end ring by injecting an aluminum-based metal into a slot of a rotor core (element plate). The present invention relates to a squirrel-cage induction motor rotor excellent in mass productivity, low cost, and high-temperature durability, and a method of manufacturing the rotor.

[0002]

2. Description of the Related Art Conventionally, there is a squirrel-cage induction motor of this type as shown in FIG.

FIG. 3 is a motor structure diagram showing the inside of a general squirrel-cage induction motor.

In FIG. 3, a cage induction motor has a stator frame 1 in which a stationary stator core 2 and a stator coil 3 fixed to the stator frame 1 are arranged. Stator core 2
Further, a rotor core 4 that rotates integrally with the rotating shaft 5 is installed inside the rotating shaft 5.

The rotor core 4 is formed by laminating a plurality of rotor core element plates 8 which are thin disk-shaped members as shown in FIG. 2, for example, in order to prevent loss due to eddy current. A slot 10 is formed in the axial direction of the outer peripheral portion.

A rod-shaped rotor bar (slot bar) 6 as shown in FIG. 4 is inserted into the slot 10.
At both ends of the rotor bar 6, end rings 12 (12a, 1a) are provided.
A short-circuit ring called 2b) is provided. The current generated by the induced electromotive force is generated by the rotor bar 6 and the end rings 12a, 1
2b, the rotating member (rotor core 4, rotating shaft 5, rotor bar 6, end ring 12) is integrally rotated by the electromagnetic force of the current and the rotating magnetic field (hereinafter, the rotating member will be referred to as the rotating member). The rotor 20).

Meanwhile, in the rotor 20 used for a small or medium capacity induction motor, an aluminum-based metal is injected into the slot 10, that is, the rotor bar 6, and the end rings 12a and 12b, and is molded by casting. Cast rotors are common.

However, in recent years, induction motors are often operated under high-speed rotation and severe use conditions (starting with a large load and increasing the frequency of stopping and starting during operation). The problem of strength reduction due to high-temperature softening of aluminum-based metals has been occurring.

In view of such a problem, Patent Publication No. 2693
No. 556 proposes a method in which the material of the aluminum-based metal is changed to a special aluminum alloy to improve the strength of the aluminum-based metal.

Japanese Utility Model Laid-Open No. 1-93967 proposes a method shown in FIGS. 5 and 6 without changing the material of the aluminum-based metal.

FIG. 5 is an enlarged view of a portion corresponding to the V portion in FIG. 3 described above, wherein 105 is a rotating shaft, 104 is a rotor core, 106 is a rotor bar, and 112 is an end ring. Are the same, only the last two digits in the figure are given the same numbers.

In this structure, a rod-shaped rotor bar 106 made of aluminum material is inserted into a slot, and its protrusion 1
A wire-shaped reinforcing member 120 is attached to the outer periphery at 06a, and the end ring 112 is cast together with the reinforcing member 120.

That is, the rotor bar 10 protruding from the core portion
6 is provided with a recess 122 (FIG. 6) in the circumferential direction on the outer periphery of the protrusion 106a, and a reinforcing material 1 such as a wire material having high hardness is provided in the recess.
20 and cast around the end ring 1
12 is being molded.

As another method, a method as shown in FIG. 7 has been proposed.

FIG. 7 shows a structure in which a strong reinforcing ring 250 is separately provided to support the end ring 212 so as to surround it.

[0016]

However, changing the material of the aluminum-based metal as disclosed in Japanese Patent Publication No. 2693556 uses a special aluminum alloy material, so that the operation is performed by lowering the conductivity and increasing the variation. It is inevitable that the characteristics of the motor decrease and the heat generation is large, and that the temperature rise of the motor is unavoidable. Also, it is difficult to produce small lots, and the productivity is low. The cost was also difficult.

In particular, the decrease in conductivity is caused by the occurrence of Los in the rotor.
s increases, the temperature rise of the cast aluminum is large, and even if the strength is increased with the special angle aluminum alloy, the result is that the temperature is softened to offset the aluminum.

Further, in the method of Japanese Utility Model Laid-Open No. 1-93967, the structure is complicated, and not only is the burden on the reinforcing member large, but also the reinforcement by the wire-like reinforcing member 120 is mainly attributable to the circumference of the end ring 112. However, there is a problem that the mechanical strength of the end ring 112 is only small and is not very useful for reinforcing the end ring 112 in the radial direction. However,
In recent years, motors are often easily exposed to further high-speed operation by inverter control or the like, and use in such severe operating conditions or in summertime is particularly remarkable for the end ring 212 made of aluminum-based metal. It has been pointed out that the strength is lowered and the strength against the centrifugal force becomes insufficient.

The present invention has been made in view of such a conventional problem, and compensates for a decrease in strength due to high-temperature softening of an aluminum-based metal cast as a rotor conductor, and is low in cost and high in conductivity. It is an object of the present invention to produce a rotor having good operating characteristics with little variation.

[0020]

SUMMARY OF THE INVENTION According to the present invention, an aluminum-based metal is injected into slots formed in each rotor core element plate in a state in which a plurality of rotor core element plates are stacked, whereby an end is provided. In a rotor of a cage induction motor in which a rotor conductor including a ring is integrally molded.
A portion of at least one rotor core element plate located at an end of the rotor core, which is located radially outward from a predetermined position in the radial direction from the center of the rotation axis of the rotor, is bent toward the end ring. By doing so, the above problem has been solved.

[0021]

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

The basic structure of the present embodiment is the same as that of the squirrel-cage induction motor described with reference to FIG. 3, and a duplicate description will be omitted.

As shown in FIGS. 2 and 4, the rotor is a rotor core 304 made of magnetic steel sheet, a rotor bar 306,
Since the end ring 312 and the end ring 312 are integrally assembled to the rotating shaft 305, and this configuration is basically the same, the same reference numerals are given to the last two digits in the figure, and the detailed description is similarly given. Omitted.

FIG. 1 is an enlarged view of a structure of a portion I in FIG. 3 as a part of the present embodiment which is greatly different from the conventional one, and the part will be described.

In the present embodiment, as shown in FIG. 1, the rotor core element plates 30 located at both ends of the rotor core 304 are provided.
As shown in FIG. 2, the portion 308 a on the outer periphery side of a predetermined position (the position indicated by the broken line) A in the radial direction of one or two or three sheets 8 is bent in a U-shape toward the end ring 312. ing.

Thereafter, an aluminum-based metal is poured,
If cast, the bent portion 308a of the rotor core element plate 308 functions as a reinforcing plate.

Since the bent portion 308a is the rotor core element plate 308 itself as described above, it is made of an iron member, and is extremely excellent in strength. Therefore, there is no need to install a separate reinforcing ring 250 as described with reference to FIG. 7, and since it has the function of a “plate-like” reinforcing member parallel to the rotating shaft 305, (the centrifugal force of the end ring 212 can be effectively reduced). Most of the centrifugal force generated in the end ring 312 can be reliably received (unlike the conventional structure of FIG. 6 which cannot be received).

The predetermined position A when bending the rotor core element plate 308 is set to a position where the joint area between the rotor bar 306 and the end ring 312 is not reduced.

Specifically, a dotted line portion A connecting the upper slot portion α and the lower slot β of the rotor core element plate 308 having a double cage slot structure shown in FIG.
And bend it. By doing this,
Since the end ring 312 is electrically divided into an upper slot and a lower slot, motor torque characteristics are also improved.

The bent portion is not limited to this configuration, but may be changed as appropriate (depending on the strength of the rotor core).

That is, the point is that one of the ends of the rotor core is
Alternatively, attach two or more rotor core element plates to the end ring 3.
What is necessary is just to bend in the U-shape to the 12 side. Note that it is not always necessary to perform bending at both axial ends of the rotor core. For example, when one motor has excellent cooling performance due to the incorporation of the motor, it is sufficient to bend only the side having poor cooling performance.

In this embodiment, the rotor core, which is an electromagnetic steel sheet, is bent. However, the present invention is not limited to the rotor core, which is an electromagnetic steel sheet, and may be a steel sheet for mechanical structure.

[0033]

As described above, by forming the rotor core element plate located at the end of the rotor core into a U-shape toward the end ring side, a special aluminum alloy can be used. In addition, it is possible to manufacture a rotor that is low in cost, has high conductivity, and has little variation, while suppressing the reduction in strength due to high-temperature softening while keeping the conventional high-purity aluminum-based metal.

[Brief description of the drawings]

FIG. 1 is a diagram showing a main part of a rotor according to an embodiment.

FIG. 2 is a diagram showing a rotor core.

FIG. 3 is a structural view of the present embodiment and a conventional cage motor.

FIG. 4 is a perspective view showing a configuration example of a rotor conductor.

FIG. 5 is a diagram illustrating a main part of a rotor according to an embodiment of the related art.

FIG. 6 is a perspective view showing a part of a rotor according to an embodiment of the prior art.

FIG. 7 is a diagram illustrating a main part of another rotor according to the related art.

[Description of Signs] 304: rotor core 306: rotor bar 305: rotating shaft 308: rotor core element plate 312: end ring 308a: bent portion

Claims (2)

[Claims] In a state in which a plurality of rotor core element plates are stacked, a rotor conductor including an end ring is integrally formed by injecting an aluminum-based metal into a slot formed in each rotor core element plate. A rotor of a squirrel-cage induction motor that is cast into a rotor, wherein at least one rotor core element plate located at the end of the rotor core is located radially outward from a predetermined position in the radial direction from the center of the rotation axis of the rotor. A squirrel-cage part is bent toward the end ring side. 2. A rotor conductor including an end ring is integrally formed by injecting an aluminum-based metal into a slot formed in each rotor core element plate in a state where a plurality of rotor core element plates are stacked. A method of manufacturing a cage-type induction motor that is formed by casting, wherein at least one rotor core element plate located at an end of the rotor core is radially outer than a predetermined position in a radial direction from a center of a rotation axis of the rotor. A method of manufacturing a rotor of a squirrel-cage induction motor, the method including a step of bending a portion at the end ring side to the end ring side.