JPH07322544A - Electric rotating machine - Google Patents

Abstract

PURPOSE:To prevent the deterioration of insulator by making an oblique notch at the upper end of the comb tooth part of a rotor clamp thereby reducing the leakage flux and eliminating local heating. CONSTITUTION:A plurality of laminate blocks of thin iron plate having predetermined thickness are stacked through a ventilation duct 2 into an annular stator core 1 having an end duct 3 and a core stopper and a stator winding is inserted into slots made in the inner side face. Similarly, a stator core 6 having an end duct 7 and a rotor clamp 10 is formed by stacking a plurality of laminate blocks of thin iron plate having predetermined thickness through a ventilation duct 3 and secondary conductor bars 8 are inserted into slots made in the outside of the rotor. The bars are connected, at the end parts through an end ring 9. This structure reduces flux leakage to the end part in the axial direction of the rotor even upon abrupt variation of load during steady operation thus preventing local heating and protecting an insulator against deterioration.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary electric machine, and more particularly to a rotary electric machine having an improved structure of an axial end portion of a laminated rotor core of an induction machine.

[0002]

2. Description of the Related Art An induction machine is an electric motor up to its synchronous rotation speed, and a generator when rotated at a speed higher than that. Therefore, it can be used as both an electric motor and a generator.

A major feature of using an induction machine as a generator is that the frequency of power generation is constant even if the rotation speed changes. Therefore, unlike a synchronous generator, there is no need for control equipment for adjusting the rotation speed, so that it is not a large-scale equipment. Further, in the case of the squirrel cage rotor, there are advantages that the structure is robust and maintenance and inspection are easy. Therefore, induction machines are suitable for relatively small-capacity power generation facilities where rotation speed fluctuations are expected, and are used in various places.

Generally, the load machine of the induction machine is mostly a wind and hydroelectric device such as a pump and a fan. In addition, fluids such as water and air are unlikely to undergo drastic fluctuations or abrupt fluctuations due to their properties.

When the load fluctuation is large (reciprocating compressor), a flywheel or the like is attached to absorb the load fluctuation. Therefore, in the induction machine, many electric and mechanical examinations at the time of starting with large fluctuations have been made and reflected in the machine structure. However, it is hard to say that the examination of abrupt changes during steady operation has been made sufficiently from the standpoint of the usage environment of induction machines.

Recently, cogeneration systems, combined cycles and the like have been attracting attention from the viewpoint of effective use of energy. These make effective use of energy that was conventionally discarded in the air or water.
For example, in a place with a boiler or the like, steam that was conventionally discarded is used to turn a turbine to generate electricity. Induction machines are used in such places.

[0007]

As described above, in the case of generating power by rotating a turbine using conventionally discarded steam, gas, etc., the amount of steam is not always constant, and conversely there is a sudden change. It is better to see. When the induction machine is used in such a place, a rapid change in the amount of steam appears as a change in the current, resulting in a rapid change in the magnetic flux. As a result, the leakage magnetic flux at the bar end in the rotor axial direction, the rotor clamp, the axial end of the laminated rotor, and the periphery thereof increases, causing local heating of the axial end of the rotor. As a result, the insulator such as the coil is accelerated to deteriorate and the life of the induction machine is shortened. However, the conventional structure does not have sufficient structural measures against local heating.

An object of the present invention is to improve the structure of an induction machine against changes in the environment in which it is used.

[0009]

As a means for eliminating local heating of the axial end portion of a rotor, the shape of a rotor clamp used as a retainer for the axial end portion of laminated thin iron plates is improved. As a first means, the comb-teeth portion of the rotor clamp is usually comb-shaped, but the upper end portion is cut out obliquely. The second means has a shape in which the comb teeth are shortened. As a third means, the upper ends of the comb teeth are cut out in a curved shape. A fourth means is such that the comb teeth are shortened and the upper end is obliquely cut out. A fifth means is that the comb teeth are shortened and the upper end is cut out in a curved shape.

[0010]

[Function] By changing the shape of the upper end of the rotor clamp comb teeth in this way, the spatial distance from the end of the laminated stator in the direction of the iron core axis and the end of the stator winding can be increased, and the magnetic resistance increases. Reduces leakage flux and eliminates local heating. As a result, deterioration of the insulator such as the coil due to heat is prevented.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a cross-sectional view of the upper half of a laminated stator core and a rotary electric machine having the laminated rotor core described above, using a squirrel cage induction motor as an example. The stator core 1 has a plurality of laminated blocks in which thin iron plates are laminated in a predetermined thickness, and a ventilation duct 2
It is formed by stacking through the end duct 3 and the iron core pressing plate. The stator core 1 forms an annular body, and a slot is provided on the inner side surface of the stator core 1 and the stator winding is inserted therein. The rotor core 6 is also formed by stacking a plurality of laminated blocks in which thin iron plates are laminated with a predetermined thickness via the ventilation duct 3, and is composed of an end duct 7 and a rotor clamp (iron core pressing plate) 10. A slot is provided on the outer side of the rotor, and the secondary conductor bar 8 is inserted therein. Further, the bars are connected at their ends by an end ring 9.

FIG. 2 is an enlarged perspective view of the portion A of FIG. FIG. 3 is a view showing only the rotor clamp. It comprises an annular body 11 with a plurality of comb teeth 12 around it. This outer diameter is slightly shorter than the outer diameter of the rotor, and a steel material is generally used as the material.

FIG. 4 shows the comb teeth of the improved rotor clamp according to the present invention, which has a structure in which the upper end portion is obliquely cut out. FIG. 5 shows another embodiment of the present invention. The comb teeth of the rotor clamp are shortened to facilitate machining. In FIG. 6, the upper end portion of the comb tooth is curvedly cut out. FIG. 7 shows the comb teeth shortened and the upper end cut out obliquely, and FIG. 8 shows the comb teeth shortened and the upper end cut out in a curved shape.

[0014]

According to the present invention, even when there is a sudden load change during steady operation, the leakage magnetic flux to the axial end of the rotor can be reduced and local heating can be prevented.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a conventional stator and rotor using an induction machine as an example.

FIG. 2 is a perspective view of a portion A in FIG.

FIG. 3 is a perspective view of a rotor clamp.

FIG. 4 is a perspective view of a main part showing an embodiment of the present invention.

FIG. 5 is a perspective view of a main part showing an embodiment of the present invention.

FIG. 6 is a perspective view of a main part showing an embodiment of the present invention.

FIG. 7 is a perspective view of a main part showing an embodiment of the present invention.

FIG. 8 is a perspective view of a main part showing an embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Stator core, 4 ... Stator winding end part, 5 ... Rotor core, 8 ... Secondary conductor bar, 9 ... End ring, 10 ... Rotor clamp.

Claims (5)

[Claims] 1. A rotary electric machine having an annular laminated stator core and laminated rotor cores rotatably arranged in an annular portion of the laminated stator core, wherein an axial end of the rotor core is provided. Rotating electric machine characterized in that the upper ends of the comb teeth of the rotor clamp that holds the portion are notched obliquely. 2. The rotary electric machine according to claim 1, wherein the comb teeth of the rotor clamp have curved upper ends. 3. The rotating electric machine according to claim 1, wherein the comb teeth of the rotor clamp are shortened. 4. The rotary electric machine according to claim 1, wherein the comb teeth of the rotor clamp are shortened and the upper end portion is obliquely cut out. 5. The rotating electric machine according to claim 1, wherein the comb teeth of the rotor clamp are shortened, and the upper end portion is cut out in a curved shape.