JPH04281347A - Wound rotor - Google Patents

Abstract

PURPOSE:To suppress abnormal torque, vibration and noise by shifting a punched slot part for containing a conductor by a predetermined distance from the center line, combining a plurality of sets of such punched slot parts, and differentiating the direction of the slot between respective unit blocks. CONSTITUTION:A plurality of steel plates 3 having punched parts 2 are laminated at a same position to form unit blocks 4A, 4B. A slot 5 is made so that the opening 5b is shifted by a predetermined distance (d) from the center line of a main section 5a and the direction of the slot 5 is reversed for every unit block 4A, 4B. Since the slot 5 is not skewed, a secondary conductor can be contained in the slot 5 easily in a short time. Furthermore, abnormal torque, vibration and noise due to driving of the rotor can be suppressed similarly with a skewed slot.

Description

[Detailed description of the invention]

[Purpose of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wound rotor having a laminated core made of laminated steel plates each having a plurality of slots for accommodating conductors formed on the outer periphery thereof.

0002

[Prior Art] In general, this type of wound rotor has a laminated core formed by laminating a large number of magnetic steel plates each having a plurality of slots formed in advance by punching or the like on the outer periphery. A winding conductor is formed by inserting a secondary conductor into the slot and connecting the unshaped ends of the secondary conductor in a predetermined connection.

In this case, when the rotor is driven, the magnetic flux that enters the laminated core from the stator through the gap contains harmonic components, and the harmonic components of this magnetic flux cause This will generate harmonic electromotive force in the secondary conductor. However, such harmonic electromotive force acts as abnormal torque on the rotor, resulting in pulsating torque and causing vibration or noise.

[0004] Conventionally, therefore, in order to suppress the adverse effects of such harmonic components, a laminated iron core in which the rotor is skewed has been used. This is a method in which the positions of the rotor slots are slightly shifted in the circumferential direction when the steel plates are laminated. For example, there is a method in which the positions of the rotor slots are shifted by one pitch of the stator slots as a whole. By doing this, the phase of the electromotive force generated in the secondary conductor is slightly shifted due to the harmonic component of the magnetic flux, so the harmonic component of the electromotive force as a whole is canceled out, and the amount that contributes to abnormal torque is suppressed. It is something that will be done.

[0005]

[Problems to be Solved by the Invention] However, the above-mentioned conventional configuration has the following problems.

First of all, when laminating steel plates while skewing them, a special jig is required to adjust the pitch, and it takes a lot of time to adjust the pitch (especially when the slots are stacked). In a completely closed type, the position of the slot cannot be seen from the outer periphery in the stacked state, which takes time and effort), which inevitably increases costs. In addition, in the case of such skew, the skew effect will be significantly reduced if the skew amount is not set appropriately, but since the appropriate skew amount has not been theoretically established, the skew Since it is necessary to make a prototype to determine the quantity, there is a problem that a large amount of cost is incurred.

Second, when a secondary conductor is housed in a laminated core having such skewed slots, the cross-sectional area of the slot is reduced, making it difficult to accommodate the secondary conductor. The present invention has been made in view of the above-mentioned circumstances, and its purpose is to provide a novel winding rotation system capable of obtaining abnormal torque, vibration, and noise suppression effects equivalent to the skew effect without skewing the laminated core. It is to provide a child. [Structure of the invention]

[0008]

[Means for Solving the Problems] The present invention provides a winding rotor formed by laminating a predetermined number of steel plates each having a punched part for forming a slot for accommodating a conductor on the outer periphery to form a laminated iron core. The punched part of the steel plate is located at a position where the bridge part or the opening on the outer circumferential side is shifted to one side by a distance d that satisfies the following conditions with respect to the center line of the main part in which the conductor is housed. The laminated core is formed by combining a plurality of stacked unit blocks such that the direction and position of the slot match the direction of the steel plate, and the direction of the slot between each unit block. It is characterized in that the main parts are different from each other and the main parts overlap. {πD/4(z+p)}≦d≦{πD/4
(z-p)} ...(A) However, D: Rotor diameter z: Number of slots in the corresponding stator p: Number of pole pairs

[0009]

[Operation] According to the winding rotor of the present invention, as shown in FIG. 1, the laminated iron core 1 is formed by laminating a plurality of steel plates 3 having punched portions 2 at the same position to form a unit block 4. 4 (the figure shows the case of two unit blocks 4a and 4b). The slot 5 is formed parallel to the axis of the rotating shaft, and has a bridge portion or an opening 5b (in the figure, the slot 5 is semi-closed and the outer peripheral side is the opening 5b) with respect to the main portion 5a. ) is formed at a position shifted by a predetermined distance d from the center line l of the main portion 5a, and the unit blocks 4a, 4b
They are arranged so that the direction of shift is opposite each time.

[0010] As a result, the main part 5a of the slot 5 has an external shape that is not inclined with respect to the axis of the rotating shaft, and when the secondary conductor 6 (see FIG. 3) is housed in the slot, Since there is no step difference in the laminated state of the steel plates 3, the cross-sectional area of the slot does not decrease.

Furthermore, since the slot 5 has a shape without an inclination, the workability of storing the secondary conductor 6 (see FIG. 3) is improved. This is because, as shown in FIG. 4, the slots 5 of the laminated core 1 are not skewed, so the work of fitting the secondary conductors 6 into the slots 5 is easier and shorter than the case where the secondary conductors 6 are skewed.

[0012] In addition, based on the principle shown below in terms of electrical characteristics, an effect similar to that obtained in the case of skewing can be obtained,
This makes it possible to suppress as much as possible abnormal torque generation, vibration, and noise associated with rotor drive.

That is, as shown in FIG. 3, the magnetic fluxes φA and φB that enter the unit blocks 4A and 4B from the stator side through the gap have different inflow paths and have a phase difference α.
(electrical angle) is generated. If the voltages induced in the secondary conductor 6 by the magnetic fluxes φA and φB are eA and eB, respectively, a phase difference α similarly occurs. This phase difference α is caused by the distance 2d corresponding to the difference in the magnetic paths of the magnetic fluxes φA and φB. Specifically, it is determined by the pole pitch τ expressed by the number of pole pairs p and the outer diameter D of the laminated iron core 1 as shown in the following equation. It is given as follows. α=2dπ/τ

...(1) However, τ=πD/2p

On the other hand, the induced voltages eA and eB are quantities expressed as vector quantities, respectively, as shown in FIG.
The voltage e actually generated in the rotor conductor 6 is the sum of these e
= eA + eB It is a value expressed as. Magnetic flux φA
and φB include harmonic components, and as a result, harmonic components are also generated in the induced voltages eA and eB. However, since there is a phase difference α between the two, the degree of the harmonic component included in the induced voltage e, which is the combined value of these, becomes a different value depending on each order. A skew coefficient Ksn indicating the degree of harmonic components included in such an induced voltage e is given by the following equation. Ksn=|eA +eB |/|eA |
+｜eB｜…(2)

00
15] Now, if the unit blocks 4A and 4B have the same thickness, |eA |=|eB |, and as shown by the vector in the conceptual diagram of FIG. 2, the value of the denominator of equation (2) is the line segment OA It is equal to twice the length 2r. Also, the size of the vector sum in the numerator of the same equation is the length q of the line segment OB in the same figure.
is equal to When these values are expressed in accordance with equation (2), they are calculated as follows. q/2r=2Rsinα/4Rsin(α
/2) =cos(α/2
)
...(3) Also, in the n-th harmonic, the phase angle α becomes n times, so if α is replaced by nα, the skew coefficient Ksn in equation (2) can be expressed as follows. Ksn=cos(nα/2)
…(4
)

Now, it is generally well known that harmonics that tend to generate abnormal torque, vibration, or noise are caused by groove harmonics due to stator slots, but the order μs of the harmonics is , is expressed as follows. μs=z/(p±1)

...(5) (However, z is the number of stator slots)

00
[17] Therefore, the value of the skew coefficient Ksn in the case of the present invention at the order shown in the above equation (5) is calculated as follows based on the equation (4). That is, first, with respect to the range (A) of the set distance d, the range of the phase difference α is expressed by the formula (
1), πp/(z+p) ≦α≦ πp/(
z-p) ... (6) Based on this result, first find the first order (n=1) case of the skew coefficient Ksn shown in equation (4). (a) At the lower limit of α, Ks1 =cos(α/2)
= cos {πp/2(z+p)}
...(7a) (b) At the upper limit of α, Ks1 = cos(α/2)
= cos {πp/2(z-p)}
...(7b) Here, in the general case, since the number of slots z of the stator is larger than the number of pole pairs p (for example, z = 48, p = 2), the (7a), (
7b) The value of equation is approximately 1. On the other hand, the skew coefficient Ksn due to the μs-order harmonic shown in equation (5) is expressed as Ksn=cos{π(z±p)/2(z±p), corresponding to the upper and lower limits of distance d, respectively.
p)} ...(8) However, ± is in any order. Here, if the numerator and denominator complexes have the same sign, Ksn=cos(π/2)=0
…(9)
Therefore, it is always zero. In addition, in the case of opposite signs, considering the general case where the number of slots z of the stator is larger than the number of pole pairs p as described above, the μth
The s-th skew coefficient Ksn can be set to approximately zero. Therefore, in any case, the skew coefficient can be set to approximately 1 for the first-order component of the voltage induced in the conductor, which effectively acts as the rotational force of the rotor.
The induced voltage of the μs-order harmonic component, which causes abnormal torque, vibration, or noise, can be reduced as much as possible, and the same effect as when skewing is achieved can be obtained.

Table 1 shows the results of calculating the skew coefficients derived in this way according to various conditions. In this case, the coefficient values when conventional skewing is performed are also shown, and the skew coefficient Kns' at that time is given by the following equation. Ksn'=sin {(nα/2)/n(α
/2)} …(11)

[0019]

[Table 1]

As can be seen from this result, when conventional skewing is performed, the value of distance d is almost a large value of 0.6 or more even in the range of formula (A), whereas in the present invention The value is less than or near 0.1, and a sufficiently large skew effect is obtained.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a high frequency motor will be described below with reference to FIGS. 6 to 9.

First, in FIG. 8 showing the overall configuration in cross section, the stator 11 is composed of a stator core 12 and a stator winding 13 housed in a slot (not shown), and the slot portion of the stator core 12 is punched out. It is formed by laminating formed steel plates without skewing.

The wound rotor 15 consists of a rotating shaft 16 supported by a bearing (not shown) and a laminated core 17 fitted to the rotating shaft 16. The laminated core 17 has slots 18.
are formed along the outer periphery. A secondary conductor 19 is housed in the slot 18 of the laminated core 17, and their ends are connected in a predetermined manner to form a wound conductor 21. Figure 4 to connect to the specified wiring
The secondary conductor 6 is bent and connected as shown by the two-dot chain line.

Next, the wound rotor 15 will be described in detail. The steel plate 22 constituting the laminated core 17 has an outer diameter of D.
As shown in FIG. 7, a large number of punched portions 23 for forming slots 18 are formed at predetermined intervals on the outer periphery. The punched portion 23 has a main portion 23a in which the secondary conductor 19 is housed and an opening 23b for generating a skew effect, which are arranged in the following relationship. That is,
The position of the opening 23b is shifted to one side by a predetermined distance d with respect to the center line l of the main portion 23a. The distance d is set as follows as a value that satisfies the condition shown in the above-mentioned formula (A). d=(πD)/(4z)
…
(stomach)

[0025] Such a steel plate 22 is placed at the same position (
In other words, a predetermined number of sheets are laminated (without skewing) to form a unit block 24 having a thickness of 1/2 of the total thickness L, and this unit block 24 is formed in the same manner and the punched part 23 is placed upside down. The laminated core 17 is constructed by combining the unit blocks 25 with the main portions 23a of the punched portions 23 overlapping each other (see FIG. 6). Therefore, when the slots 18 of the laminated core 17 are viewed in the axial direction of the rotating shaft 16, as shown in FIG.
The positional relationship will be shifted by the amount.

In this way, the slots 18 of the laminated core 17
are formed parallel to the axial direction of the rotating shaft 16, making it easy to accommodate the secondary conductor 19 in the slot 18. Note that, unlike the case where the conductor is formed by casting in this way, the steel plate 22 is not brought into a high temperature state. As a result, the steel plate 22, which is an amorphous magnetic material, is not crystallized, can maintain excellent properties of tensile strength, and can sufficiently withstand high-speed rotation conditions. Further, in the rotating state, the following skew effect is obtained. That is, in this embodiment, since the distance d mentioned above is set as shown in equation (a),
The value of phase difference α corresponding to equation (6) is α=pπ/z

...(b). Therefore, the skew coefficient Ksn has the following value corresponding to equations (7a), (7b), and equation (8). (a) First-order case (n=1) Ks1 = cos(πp/2z)
...(c) (b) In the case of μs {μs=z/(p±1)}
Ksn=cos[π/2{1±(p/z)}]
(d) Now, for example, if the number of slots z in the stator is 36 and the number of pole pairs p is 2, the results will be as shown in Table 2.

[0027]

[Table 2]

As a result, the value of the skew coefficient Ksn in equation (c) is 0.996, so it can be regarded as approximately 1, and the value of the skew coefficient Ksn in equation (d) is 17th order,
Since both the 19th orders are 0.087, they can be considered to be approximately zero. Therefore, the skew coefficients Ksn and Ks of the conventional and this embodiment are
Comparing n', in the case of the 17th and 19th orders, in the case of this embodiment, it has decreased from 13% in the conventional case to 15%. Therefore, since the harmonic torque is reduced, the generation of abnormal torque is suppressed as much as possible, and the generation of vibration and noise is also reduced.

FIG. 9 shows the relationship between the rotational speed and torque of the wound motor using the wound rotor of this embodiment. In the figure, the solid line shows the characteristics of this embodiment, the broken line shows the characteristics when conventional skew is performed, and the dashed line shows the characteristics when no skew is performed. According to this result, when the rotation speed increases in a non-skewed model, the torque decreases and an abnormal torque generation state occurs, whereas in this example, the decrease in torque is improved by reducing the harmonic torque. It can be seen that the skew effect exhibits characteristics equal to or better than those of the conventional skewed one. Therefore, the engine can be started smoothly and accelerated in a short time. In the above embodiment, the slot 18 is of a semi-closed type, but it is not limited to this and may be of a fully closed type.Also, although the value of the distance d is set as shown in equation (a), However, it may be within the range shown in formula (A). Furthermore, in the above embodiment, the unit block 24
and 25 have been described, but the invention is not limited to this, and three or more may be provided.

[0030]

As explained above, according to the wound rotor of the present invention, the slot portions are formed parallel to the axial direction of the rotating shaft by laminating the laminated cores at the same position. When storing the secondary conductor, there is no skew when storing the secondary conductor in the slot, so it is easy to store, and since the cross-sectional area of the slot does not decrease, the cross-sectional area of the secondary conductor can be increased and the characteristics of the rotor can be improved. Furthermore, the bridge part or opening of the slot can be moved from the center line of the main part to the formula (A).
Since the distance d is set in the range shown by , the same effect as skewing can be obtained, and the rotor can suppress the generation of abnormal torque due to harmonic components as much as possible, as well as the generation of vibration and noise. It has excellent effects.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view showing the appearance of a laminated core.

FIG. 2 is an explanatory diagram showing electromotive force induced in a conductor.

FIG. 3 is an explanatory diagram showing the state of magnetic flux entering the slot.

FIG. 4 is an explanatory diagram when a secondary conductor is housed in the rotor core.

FIG. 5 is a side view of FIG. 4.

FIG. 6 is a partial plan view of the steel plate.

FIG. 7 is a partial horizontal plan view of the laminated core.

FIG. 8 is a vertical sectional side view of the overall configuration.

FIG. 9 is a characteristic diagram showing the correlation between rotation speed and torque.

[Explanation of symbols]

1, 17...Laminated core, 2, 23...
Punching part, 3, 22... steel plate,
4A, 4B, 24, 25...Single block, 5, 18...Slot, 5a, 23
a...Main part, 5b, 23b...Bridge part (or opening)
, 6, 19... Secondary conductor, 11... Stator, 12... Stator core, 1
5... Wound rotor, 16... Rotating shaft,
21...Wound conductor.

Claims (1)

[Claims] 1. A wound rotor comprising a laminated core formed by laminating a predetermined number of steel plates in which punched portions for forming slots for accommodating conductors are formed on the outer periphery, the steel plates being punched. The part is formed in an asymmetrical shape such that the bridge part or the opening part on the outer peripheral side thereof is shifted to one side by a distance d satisfying the following condition with respect to the center line of the main part in which the conductor is housed, and The iron core is formed by combining a plurality of unit blocks in which a plurality of the steel plates are laminated so that the direction and position of the slot coincide with each other, and in each unit block, the direction of the slot is different from each other and the main part overlaps. A wound rotor characterized in that it is configured as follows. {πD/4(z+p)}≦d≦{πD/4(z−p)}
However, D: rotor diameter z: number of slots in the corresponding stator p: number of pole pairs