JPH1175330A - Rotor and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotor which can improve the efficiency of a motor and a generator, and reduce manufacturing cost. SOLUTION: This rotor is formed by layering steel sheets, and is constituted of a rotor iron core 2 involving a number of slots 8 formed by means of punching in its layered direction, a conductor block 7 integrally-formed with the first short-circuit ring 4 by means of molding at the one end of a conductor bar 3 of bar shape inserted into the respective slots 8, and the second short- circuit ring 5 welded to the other end of the conductor bar 3. It is thus possible to improve rotational performance by eliminating an increase in electric resistance due to a welded part between the conductor bar 3 and the first short- circuit ring 4, and reduce processing cost and assembling cost by integrally- forming the conductor bar 3 and the short-circuit ring 4 at a time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotor used for an induction motor or a generator, and more particularly to a rotor having improved conductor bars and short-circuit rings in a laminated core slot and a method for manufacturing the same.

[0002]

2. Description of the Related Art The structure of a conventional cage rotor is shown in FIG. A rotor core 32 formed by laminating a number of steel plates punched with a rotor slot 30 and a shaft hole 31 is used.
The rotor slots 30 are grooves into which the conductor bars 33 made of a conductive material are inserted, and are provided in large numbers in the circumferential direction. The rotor core 32 is a magnetic circuit. The conductor bar 33 is inserted into the rotor slot 30 of the laminated rotor core 32,
A circuit is formed in which both ends are short-circuited by annular short-circuit rings 34 and 35 to form a conductor portion and a current flows. On the other hand, the rotating shaft 36 is fixed to the shaft hole 31 by press-fitting, shrink fitting, or the like, and supports the rotor and transfers power. Conductor bar 33
The short-circuit rings 34 and 35 are both formed using copper or a copper alloy, and are formed by driving the conductor bar 33 and welding the short-circuit rings 34 and 35.

As shown in FIGS. 8 and 9, a conductor bar 33 and short-circuit rings 34 and 35 are formed of aluminum or an aluminum alloy with respect to a rotor core 32, and are integrally formed by die casting or casting. Some are also known.

[0004] The rotor manufactured by the above method is
It is incorporated in a separately manufactured stator and constitutes an induction motor or a generator to transfer power.

[0005]

By the way, in the conductor of the rotor of a motor or a generator, it is required to improve the rotation efficiency by lowering the electric resistance and improving the conductivity. At the same time, there is a demand for a reduction in manufacturing costs.

However, the conventional method of manufacturing a conductor portion including a conductor bar and a short-circuit ring has the following problems.

(1) In the case of integrally molding by aluminum die casting or casting In order to use a molten aluminum alloy at about 700 ° C. or higher,
Inevitably causes thermal deformation of the rotor core.

[0008] At the time of casting or cooling, air easily enters the inside of the conductor, and a cavity is generated. Further, even if a material having high purity is used, impurities are mixed. If there are many voids and impurities, the electrical resistance of the conductor increases, which adversely affects the rotational performance. However, it is difficult to control the casting conditions, etc., to manufacture the product while suppressing the occurrence of voids and the incorporation of impurities, and a certain variation value must be allowed.

[0009] It is difficult to cast other than aluminum and aluminum alloy. Therefore, copper or copper alloy having better conductivity than aluminum cannot be used.

(2) When a copper or copper alloy conductor bar is inserted and both end faces are joined with a short-circuit ring, a necessary number of conductor bars must be prepared as a single body.
Usually, the conductor bar is manufactured by drawing, extruding, or cutting, which has increased the cost. In addition, it is necessary to control each dimension, which also causes an increase in cost.

[0011] Since the conductor bars must be inserted one by one by driving or the like, workability is poor, and both ends must be welded by short-circuit rings, which increases the assembly cost.

[0012] Since the conductor bar and the short-circuit ring are welded, a gap may be generated or impurities may be mixed into the welded portion. If there are many gaps or impurities, the electrical resistance of the conductor increases, which adversely affects the rotational performance.

An object of the present invention is to solve the above-mentioned conventional problems, and to provide a rotor capable of improving the efficiency of a motor or a generator and reducing the manufacturing cost, and a method of manufacturing the same.

[0014]

A rotor according to the present invention is formed by laminating thin steel sheets, and has a rotor core having a number of slots formed by punching in the laminating direction, and a rod-shaped core inserted into each slot. A conductor block comprising a conductor bar and a first short-circuit ring integrally molded at one end of the conductor bar; and a second short-circuit ring welded to the other end of the conductor bar. By using a conductor block in which the first short-circuit ring is integrally formed, there is no increase in electric resistance due to mixing of impurities and generation of a gap in a welded portion between the conductor bar and the first short-circuit ring, thereby improving rotational performance. In addition, by simultaneously molding the conductor bar and the short-circuit ring, the processing cost can be reduced as compared with the case of individually processing the conductor bar, and the conductor bar can be inserted into the slot at one time, and For over a good only welding the second short ring can reduce the assembly cost.

Further, when the conductor block is formed of a forged product, there is no increase in electric resistance due to mixing of impurities or the occurrence of a cavity when casting, and it is possible to improve the conductivity and the rotational performance, and to improve the high temperature. As a result, thermal deformation does not occur, the material limitation is reduced, a material having higher conductivity can be used, and the rotation performance can be improved.

According to the method of manufacturing a rotor of the present invention, there are provided a step of manufacturing a rotor core in which thin steel sheets are laminated and a number of slots are punched out in the laminating direction, and a rod-shaped conductor bar inserted into the slots. Forging a conductor block comprising a first short-circuit ring at one end of the conductor bar by forging; inserting the conductor bar into a slot to bring the first short-circuit ring into contact with one end of the rotor core; A step of welding the second short-circuit ring brought into contact with the other end of the iron core and the other end of the conductor bar, so that a rotor using the conductor block made of the forged product can be obtained.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a rotor and a method of manufacturing the same according to the present invention will be described below with reference to FIGS.

In FIGS. 1 and 2, reference numeral 1 denotes a cage rotor, and a first short-circuit ring for short-circuiting a rotor core 2, a conductor bar 3 made of a number of conductive materials, and one end of the conductor bar 3. 4
And a second short-circuit ring 5 for short-circuiting the other end of the conductor bar 3, and a rotating shaft 6 penetratingly fixed to the shaft core of the rotor core 2. The conductor bar 3 and the first short-circuit ring 4 are constituted by a conductor block 7 integrally formed, and the second short-circuit ring 5 is welded to the other end of the conductor bar 3.

The rotor core 2 constitutes a magnetic circuit. As shown in FIG. 2, the rotor core 2 is formed by laminating a large number of steel plates having punched slots 8 and shaft holes 9. The slots 8 are grooves into which the conductor bars 3 are inserted, and are arranged in a large number in the circumferential direction. Both ends of the conductor bar 3 are annular first and second ends.
Are formed by the short-circuiting rings 4 and 5 of the conductor portion 10 forming a circuit for flowing a current. The conductor part 10 is composed of two parts, a conductor block 7 and a second short-circuit ring 5, both of which are made of copper, a copper alloy, aluminum or an aluminum alloy. The rotating shaft 6 is fixed to the shaft hole 9 by press-fitting, shrink fitting, or the like, and is configured to support the rotor 1 and transfer power.

The conductor block 7 is plastically worked by cold or warm forging by a press 11 shown in FIGS. In FIG. 3, reference numeral 12 denotes an upper die, and a punch 13 is arranged below the upper die 12. A counter pin 14 is provided at the axis of the punch 13 so as to be retractable. 1
Reference numeral 5 denotes a lower die, on which a guide ring 16 into which the punch 13 is fitted is disposed. This guide ring 16
The raw material 20 is inserted inside to form the outer periphery of the first short-circuit ring 4. A die 17 for forming the conductor bar 3 is disposed below the guide ring 16, and a knockout 18 is provided so as to be able to retreat into the conductor bar forming space of the die 17.

Next, a process of manufacturing the conductor block 7 by the press 11 will be described with reference to FIGS. FIG. 3 shows a state in which the upper mold 12 is at the top dead center, and the material 20 is inserted into the guide ring 16 of the lower mold 15. The raw material 20 is cylindrical or columnar.

The tool portion of the mold is lubricated. FIG. 4 shows a state in which the upper die 12 is lowered to the bottom dead center, and the material 20 is extruded downward in the die 17 by the punch 13 to form the conductor bar 3. On the other hand, the central portion 20a of the material 20 is pushed backward, and pushes up the counter pin 14. The material 20 enters the conductor bar forming space of the die 17 and its cross section is reduced, and is several times higher than the original height, so that the conductor bar 3 having a predetermined height is formed.

FIG. 5 shows a state in which the upper die 12 is raised and is in the top dead center state again. The formed conductor block 7 is pushed out of the die 17 by the knockout 18 and taken out. Finally, the end face of the conductor block 7 is finished in a predetermined shape and washed.

Thereafter, as shown in FIG. 1, the slot 8 of the rotor core 2 is inserted into the conductor bar 3 of the conductor block 7, and the second short-circuit ring 5 is inserted thereon, so that the conductor block 7 and the second Are welded, and the rotor 1 is completed.

The conductor block 7 forged as described above
In FIG. 6, the metal fibers 19 continue toward the conductor bar 3 protruding from the first short-circuit ring 4 as shown in FIG. Therefore, the strength of the conductor bar 3 increases. Also,
Since no voids are generated and no impurities are mixed in the aluminum die-cast, the conductive bar 3 having low electric resistance and good conductivity can be obtained. For example, forged aluminum products have about 1-5% lower resistance than aluminum die-cast products, thereby improving the efficiency of motors and generators. In addition, the conductor bar 3
Also, when the shorted rings 4 and 5 are welded to each other, the electrical resistance of the welded portion is increased. However, in the conductor block 7 of the forged product, the metal fibers are continuous between the conductor bar 3 and the first shorted ring 4. Therefore, no resistance loss occurs. In the case of aluminum die-casting, thermal deformation is caused to reach a high temperature of about 700 ° C. or higher, but no thermal deformation occurs because no heat is used.

When copper is used as a material, it is difficult to form the material by die casting or casting, but it can be integrally formed by forging. However, since the deformation resistance of copper is greater than that of aluminum, a large processing load is required at the time of forging, and the height of the conductor bar 3 is hard to come out.

Further, as compared with the case where the conductor bar 3 and the short-circuit ring 4 are formed as separate parts, the production cost of the conductor bar 3 is reduced. Further, since a large number of conductor bars 3 are simultaneously molded by one mold, a predetermined molding accuracy can be obtained only by controlling the accuracy of the mold, and the high-quality conductor portion 10 can be manufactured at a reduced cost. Also, as compared with the case where the short-circuit rings 4 and 5 are welded and fixed to both ends of the conductor bar 3, only the other end of the conductor bar 3 and the second short-circuit ring 5 need to be welded, so that the assembly cost can be reduced.
Further, since a large number of conductor bars 3 can be inserted into the slots 8 of the rotor core 2 at one time, workability and work time are also improved.

[0028]

According to the rotor of the present invention, as is apparent from the above description, a rotor core having a number of slots, a bar-shaped conductor bar inserted in each slot, and one end of each of these conductor bars. Since there is provided a conductor block comprising a first short-circuit ring integrally formed and a second short-circuit ring welded to the other end of the conductor bar, a welded portion between the conductor bar and the first short-circuit ring The rotation performance can be improved because there is no increase in electric resistance due to the contamination of impurities and the generation of gaps in the wire. Also, by simultaneously molding the conductor bar and the short-circuit ring, the machining cost is higher than when individual conductor bars are machined. Can be reduced,
In addition, since the conductor bar can be inserted into the slot at one time and the conductor bar and the second short-circuit ring need only be welded, effects such as reduction in assembly cost are exhibited.

Further, when the conductor block is formed of a forged product, there is no increase in electric resistance due to contamination of impurities or the occurrence of a void when casting is performed, so that it is possible to improve the conductivity and the rotational performance, and to increase the high temperature. As a result, no thermal deformation occurs, and the material is less restricted, so that a material having higher conductivity can be used, and the rotation performance can be improved.

According to the method of manufacturing a rotor of the present invention, a rotor core is manufactured, a conductor block including a rod-shaped conductor bar and a first short-circuit ring is manufactured by forging, and a conductor bar is formed in a slot. By inserting the first short-circuit ring into one end of the rotor core and welding the second short-circuit ring in contact with the other end of the rotor core and the other end of the conductor bar. A rotor using the conductive block having the above structure can be obtained.

[Brief description of the drawings]

FIG. 1 is a semi-longitudinal sectional front view of an embodiment of a rotor of the present invention.

FIG. 2 is an exploded perspective view of the rotor of the embodiment.

FIG. 3 is a vertical sectional view of a press for manufacturing the conductor block according to the embodiment.

FIG. 4 is a longitudinal sectional view of a forging step of a conductor block by the same press.

FIG. 5 is a longitudinal sectional view showing a state where forging of a conductor block by the press is completed.

FIG. 6 is a sectional view of a forged conductor block.

FIG. 7 is a front view of a semi-longitudinal section of a conventional rotor.

FIG. 8 is a semi-longitudinal sectional front view of another conventional rotor.

FIG. 9 is a perspective view of the rotor of the conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rotor 2 Rotor iron core 3 Conductor bar 4 First short-circuit ring 5 Second short-circuit ring 7 Conductor block 8 Slot

Claims (3)

[Claims] 1. A rotor core having a plurality of slots formed by laminating thin steel sheets and punched in the laminating direction, a bar-shaped conductor bar inserted into each slot, and integrally formed with one end of the conductor bar. And a second short-circuit ring welded to the other end of the conductor bar. 2. The rotor according to claim 1, wherein the conductor block is made of a forged product. 3. A step of producing a rotor core in which thin steel sheets are laminated and a number of slots are punched out in the laminating direction, a rod-shaped conductor bar inserted into the slot, and a first end of one end of the conductor bar. A forging a conductor block consisting of a short-circuit ring of the type described above and inserting a conductor bar into a slot to bring the first short-circuit ring into contact with one end of the rotor core and to contact the other end of the rotor core. Welding a second short-circuit ring and the other end of the conductor bar.