JP5319159B2 - Basket type rotor - Google Patents

Description

  The present invention relates to a cage rotor.

In a so-called double squirrel-cage rotor in which an outer peripheral slot and an inner peripheral slot are provided on the rotor core, a large current flows through the conductor stored in the outer peripheral slot due to the skin effect when the induction motor is started, and the inner peripheral slot is in operation during operation. It is known that a large amount of current flows through the conductor housed in the conductor. Therefore, it has been proposed that a high-resistance conductor is accommodated in the outer peripheral slot to improve the starting characteristics, and a low-resistance conductor is accommodated in the inner peripheral slot to improve efficiency during operation (patent) Reference 1). In addition, in order to improve the starting characteristic (torque ripple), it has been proposed to provide a skew in the slot (see Patent Document 2).
Japanese Patent Laid-Open No. 51-8507 JP 2002-315237 A

  However, in a double squirrel-cage rotor, in order to provide a skew in the outer peripheral slot, is it necessary to form a peripheral slot with a skew by rotating a mold that forms the outer peripheral slot in the iron core material in the punching process of the iron core material? In addition, an operation such as laminating while rotating the core material by a predetermined angle in the laminating process of the iron core material is required. For this reason, there is a problem that work in a manufacturing process such as a punching process or a lamination process becomes complicated.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a cage rotor that improves the characteristics at the start, improves the efficiency during operation, and simplifies the work in the manufacturing process. It is in.

The squirrel-cage rotor of the invention of claim 1 is formed by punching a steel plate, and has a plurality of inner peripheral slots and a plurality of outer peripheral slots shifted by a predetermined angle in the rotational direction or counter-rotating direction with respect to the inner peripheral slots. A rotor core provided with a first block formed by laminating a plurality of cores, and a second block formed by laminating a plurality of the core cores in a state where the iron core material is reversed, and a reference line passing through the center of the rotor core. The inner peripheral side conductor accommodated in the inner peripheral slot formed symmetrically and the outer periphery formed in a substantially rectangular shape on the rotor core , the center position of which is shifted by a predetermined angle with respect to the center of the inner peripheral slot And an outer peripheral conductor that is housed in a slot by die casting and has a larger electric resistance than the inner peripheral conductor, and each of the outer peripheral slots combines the first block and the second block. In this state, the rotor core has a common positional relationship in the circumferential direction between the first block and the second block, and a circumferential positional relationship between the first block and the second block. The outer peripheral conductor is continuous between the first block and the second block in the common region in the axial direction of the rotor core, The region is discontinuous between the first block and the second block.

  According to the squirrel-cage rotor according to the first aspect of the present invention, the iron core material having the outer peripheral slot shifted by a predetermined angle in the rotational direction or the counter-rotating direction with respect to the inner peripheral slot is reversed and stacked to form the rotor core. doing. Therefore, it is only necessary to manufacture one type of iron core material in the punching process, and it is not necessary to perform so-called rolling and the like in the lamination process. Further, the skew of the outer peripheral slot of the squirrel-cage rotor is shifted to give a pseudo skew. Furthermore, the inner peripheral slot where a large amount of current flows during operation contains an inner peripheral conductor having a small electrical resistance, and the outer peripheral slot through which a large current flows during starting has a larger electric resistance than the inner peripheral conductor. Is stored. Therefore, it is possible to improve the characteristics at the time of starting, improve the efficiency during operation, and simplify the work in the manufacturing process.

Hereinafter, an embodiment of a cage rotor according to the present invention will be described with reference to the drawings.
A cage rotor (hereinafter simply referred to as a rotor) 1 of an induction motor includes a rotor core 2, an end ring 3 and a rotating shaft 4 as shown in FIG. The rotor core 2 is formed by laminating a plurality of iron core materials 5 in the plate thickness direction, and is divided into two blocks 2a and 2b having substantially the same thickness. The end rings 3 are provided at both ends of the rotor core 2 in the axial direction. The rotating shaft 4 passes through the rotor core 2 in the axial direction and is fixed to the rotor core 2.

  The rotor core 2 has an outer peripheral slot 6 and an inner peripheral slot 7. As shown in FIG. 3, a plurality of outer peripheral slots 6 are provided at equal intervals in the circumferential direction of the rotor core 2, and penetrate the rotor core 2 in the axial direction. The outer peripheral slot 6 houses an outer peripheral conductor 8 made of pure aluminum. The outer peripheral conductor 8 accommodated in the outer peripheral slot 6 is formed integrally with the end ring 3 by, for example, aluminum die casting. Therefore, the outer peripheral conductor 8 housed in the outer peripheral slot 6 is short-circuited by the end ring 3 at both axial ends of the rotor core 2. Note that the outer conductor 8 accommodated in the outer slot 6 may be made of high resistance aluminum or the like having a higher electrical resistance than pure aluminum.

  A plurality of inner circumferential slots 7 are provided at equal intervals in the circumferential direction inside the outer circumferential slot 6 in the radial direction of the rotor core 2, and penetrate the rotor core 2 in the axial direction. The inner peripheral slot 7 accommodates an outer peripheral conductor 8 accommodated in the outer peripheral slot 6, that is, an inner peripheral conductor 9 made of pure copper having a lower electrical resistance than pure aluminum. Pure copper as the inner peripheral conductor 9 is formed in a substantially trapezoidal shape, and is short-circuited by end rings 3 at both ends in the axial direction of the rotor core 2 through the rotor core 2.

  The rotor core 2 further has a slit 10 and a shaft hole 11. The slit 10 connects the outer peripheral slot 6 and the inner peripheral slot 7 in each iron core member 5, thereby preventing the magnetic flux acting from the stator (not shown) from wrapping around the outer peripheral conductor 8. ing. The shaft hole 11 is provided in the inner periphery of the rotor core 2 and the rotation shaft 4 is inserted therein. The shaft hole 11 is provided with a key 12. The key 12 engages with a key groove 13 provided on the rotary shaft 4.

Next, a method for manufacturing the rotor core 2 will be described.
As shown in FIG. 4, the iron core material 5 forming the rotor iron core 2 is formed, for example, by punching a strip-shaped electromagnetic steel sheet 14. The outer peripheral slots 6, the inner peripheral slots 7 and the slits 10 provided in the iron core material 5 are all formed in the circumferential direction of the iron core material 5 in a single punching process (step S1). In step S <b> 1, at this time, the outer peripheral slot 6, the inner peripheral slot 7, and the slit 10 are formed at equal intervals in the circumferential direction of the iron core material 5. When punching of the outer peripheral slot 6, the inner peripheral slot 7, and the slit 10 is completed, the outer edge of the iron core material 5 is punched to form the iron core material 5 (step S2). For the sake of explanation, the outer edge of the iron core material 5 is schematically shown by a two-dot chain line in step S1.

  As shown in FIG. 3, the outer peripheral slot 6 provided in the iron core material 5 in step S <b> 1 has an asymmetric shape on the left and right with respect to a reference line L <b> 1 passing through the center of the rotor core 2 and the center of the inner peripheral slot 7. have. That is, the center position of the outer peripheral slot 6 is shifted from the inner peripheral slot 7 in the rotation direction of the rotor core 2 (counterclockwise in FIG. 3). On the other hand, the inner circumferential slot 7 and the slit 10 have a symmetrical shape with respect to the reference line L1.

  The iron core material 5 provided with the inner circumferential slot 7, the slit 10, and the outer circumferential slot 6 shifted in the rotational direction with respect to the inner circumferential slot 7 is laminated to a thickness approximately half that of the rotor core 2, and the block 2a is laminated. Form. Moreover, this iron core material 5 forms the block 2b by being laminated by inverting the front and back of the block 2a. That is, the block 2a and the block 2b have the outer peripheral slots 6 whose directions from the reference line L1 are opposite to each other. The rotor core 2 has a block 2a having an outer peripheral slot 6 whose center position is shifted in the rotation direction as shown in FIG. 3, and the center position is shifted in the counter-rotation direction (clockwise in FIG. 5) as shown in FIG. The blocks 2b having the outer peripheral slots 6 are laminated so that the keys 12 coincide with each other.

  In the rotor core 2 formed by the above-described method, as shown in FIG. 1, the center C1 of the outer peripheral slot 6 in the block 2a and the center C2 of the outer peripheral slot 6 in the block 2b are mutually relative to the reference line L1. Each of the opposite directions is deviated by a predetermined angle θ. Here, the predetermined angle θ is set in advance based on the magnitude of the pseudo skew given to the rotor 1. As a result, the outer peripheral slot 6 provided in the rotor core 2 is given a deviation of 2 × θ degrees from the center position, that is, a pseudo skew.

  As shown in FIG. 1, the outer peripheral slot 6 has a common area A1 in which the relative positional relationship of the outer peripheral slot 6 is the same and the direction of deviation from the reference line L1, as shown in FIG. And a shift region A2 that are opposite to each other. Therefore, the outer peripheral slot 6 is continuous in the axial direction by the common region A1 in the blocks 2a and 2b.

  On the other hand, the inner circumferential slot 7 and the slit 10 have a symmetrical shape with respect to the reference line L1. For this reason, the inner peripheral slot 7 and the slit 10 have the same positional relationship in the circumferential direction of the rotor core 2 when the core material 5 is reversed and stacked. That is, the inner peripheral slot 7 and the slit 10 are continuous in the axial direction of the rotor core 2.

  The outer peripheral slot 6, the inner peripheral slot 7, and the slit 10 are provided at equal intervals over the circumferential direction of the iron core material 5. Therefore, the relationship between the common region A1 and the shift region A2 of the outer peripheral slot 6 and the positional relationship between the inner peripheral slot 7 and the slit 10 have the above-described positional relationship on the entire circumference of the rotor core 2, respectively.

  After the iron core material 5 is laminated to form the rotor core 2, a pure copper bar as the inner peripheral side conductor 9 is stored in the inner peripheral slot 7, and the outer peripheral side conductor 8 is stored in the outer peripheral slot 6 by aluminum die casting. And the rotating shaft 4 is inserted in the shaft hole 11, and the rotor 1 is manufactured. When the outer peripheral side conductor 8 is housed in the outer peripheral slot 6, the end ring 3 is integrally formed.

  In this way, the iron core material 5 having the outer peripheral slot 6 having an asymmetric shape with respect to the reference line L1 and the inner peripheral slot 7 and the slit 10 having a symmetrical shape with respect to the reference line L1 is reversed. In the rotor 1 formed by stacking, as shown in FIG. 2, the center positions of the outer peripheral slots 6 are shifted from each other in the circumferential direction in the blocks 2a and 2b. In FIG. 2, one of the outer peripheral slots 6 and the inner peripheral slots 7 provided in the circumferential direction is schematically shown.

Next, the operation and effect of the rotor 1 configured as described above will be described.
The rotor core 2 is formed of a block 2a and a block 2b in which the core material 5 is reversed and laminated. That is, the rotor core 2 is formed of one type of core material 5 having the outer peripheral slot 6, the inner peripheral slot 7, and the slit 10 having the same shape. Therefore, in the punching process of the iron core material 5, it is possible to form the iron core material 5 with one type of mold, and it is not necessary to perform so-called rolling in the lamination process. Therefore, the operations in the punching process and the laminating process of the iron core material 5 can be simplified.

  Further, the outer peripheral slot 6 provided in the rotor core 2 is shifted in the center position between the blocks 2a and 2b. Therefore, the outer peripheral conductor 8 housed in the outer peripheral slot 6 is given a center position shift, that is, a pseudo skew. On the other hand, no skew is given to the inner peripheral conductor 9 accommodated in the inner peripheral slot 7. Therefore, the characteristics at the time of starting can be improved.

  Further, the outer peripheral conductor 8 through which a large current flows at the time of starting is formed of pure aluminum, and the inner peripheral conductor 9 through which a large amount of current flows during operation is formed of pure copper having an electric resistance smaller than that of pure aluminum. Therefore, the efficiency during operation can be improved.

(Other embodiments)
The rotor core 2 according to the above-described embodiment has a substantially rectangular outer peripheral slot 6. However, the shape of the outer peripheral slot 6 may be another shape as shown in FIG. 6, for example, as long as it forms the common region A1 and the shift region A2 when the layers are reversed and stacked. The shape of the inner peripheral slot 7 and the slit 10 is not limited to the outer peripheral slot 6 and may be any shape. Moreover, you may set the presence or absence of the slit 10 arbitrarily.

  Further, the outer peripheral slot 6, the inner peripheral slot 7 and the slit 10 may be formed by separate punching steps. Further, instead of punching the belt-shaped electromagnetic steel sheet 14, the outer peripheral slot 6, the inner peripheral slot 7 and the slit 10 may be provided after the iron core material 5 is punched into a circle.

  The present invention described above is not limited to the above-described embodiment, and can be applied to various embodiments without departing from the gist of the invention, for example, applicable to all induction machines.

Sectional drawing which shows the outline of the rotor core by one Embodiment of this invention Schematic showing the rotor Sectional view along line III-III in FIG. Schematic diagram showing the punching process of iron core material Sectional drawing which follows the VV line of FIG. The schematic diagram which shows the outer periphery slot in other embodiment of this invention

Explanation of symbols

  In the drawings, 1 is a rotor, 2 is a rotor core, 2a is a block (first block), 2b is a block (second block), 5 is a core material, 6 is an outer peripheral slot, 7 is an inner peripheral slot, 8 is An outer peripheral side conductor, 9 is an inner peripheral side conductor, and 14 is an electromagnetic steel plate (steel plate).

Claims (2)

A first block formed by punching a steel plate, and a plurality of inner core slots and a plurality of core members each having a plurality of outer peripheral slots shifted by a predetermined angle in the rotational direction or counter-rotating direction with respect to the inner peripheral slots; A rotor core provided with a second block formed by stacking a plurality of core cores in a state in which the front and back are reversed;
An inner circumferential conductor housed in an inner circumferential slot formed symmetrically with respect to a reference line passing through the center of the rotor core;
An outer peripheral conductor formed in a substantially rectangular shape on the rotor core and housed by die casting in an outer peripheral slot whose center position is deviated by a predetermined angle with respect to the center of the inner peripheral slot, and having a larger electric resistance than the inner peripheral conductor When,
With
Each of the outer peripheral slots has a common region in which the positional relationship in the circumferential direction of the rotor core is common to the first block and the second block in a state where the first block and the second block are combined. Forming a displacement region in which the positional relationship in the circumferential direction is opposite to each other in the first block and the second block;
The outer peripheral conductor is continuous between the first block and the second block in the common region in the axial direction of the rotor core, while the first block and the second in the shift region. A cage rotor characterized by being discontinuous with the block.   The squirrel-cage rotor according to claim 1, wherein the inner peripheral conductor is made of copper, and the outer peripheral conductor is made of aluminum.

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