JP2015033304A - Electric motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric motor capable of suppressing eddy current to be Joule loss without requiring processing of a conductor part, etc.SOLUTION: An electric motor has: a stator; and a rotor 3 which is arranged on an inner peripheral side of the stator via an air gap, and in which a plurality of hollow slots 4a extending in an axial direction are formed along a circumferential direction. The rotor 3 is constituted by alternately laminating a first steel plate 6 on which a slot opening 6a corresponding to a slot 4a is formed and a second steel plate 7 in the axial direction. The first steel plate 6 has a penetrating part 6b penetrating between its marginal part and the slot opening 6a, and the second steel plate 7 has a penetrating part 7b penetrating between its marginal part and the slot opening. Then, the penetrating part 6b on the first steel plate 6 and the penetrating part 7b on the second steel plate 7 alternate with each other on the border of a slot center Cs, and are arranged in relation that edge parts of the steel plates forming the penetrating parts 6b, 7b match to the slot center Cs.

Description

  The present invention relates to an electric motor.

  A squirrel-cage induction motor is known as an electric motor. In the squirrel-cage induction motor, there is a problem that eddy currents are generated near the rotor surface of the conductor and harmonic loss occurs due to the harmonic magnetic flux that does not contribute to the torque interlinking with the rotor surface.

  As one countermeasure against this point, for example, Patent Document 1 discloses an induction motor having the following configuration. In the induction motor, the rotor is disposed concentrically with the stator via a predetermined gap on the inner peripheral portion of the stator, and is disposed at a predetermined interval in the circumferential direction and continuously in the axial direction. It has a plurality of formed slots. A through portion that penetrates the slot is provided on the rotor surface side of the slot.

Japanese Patent No. 3606022

  However, in the rotor disclosed in Patent Document 1, when the conductor in the slot is formed by casting, it is necessary to prevent the conductor from flowing into the through portion. In this case, a method of filling the penetrating portion with a mold is conceivable, but it is expected that it is difficult to fill such a narrow portion with a mold. For this reason, a method of removing the conductor in the penetrating part by machining after casting is conceivable, but there is a concern about cost increase associated with the machining. On the other hand, there is a method in which a rod-shaped conductor is inserted into the slot from the axial direction instead of casting and joined to the end ring, but productivity is significantly reduced compared to casting, which is not a good idea.

  This invention is made | formed in view of this situation, The objective is providing the electric motor which can suppress a Joule loss, without processing a conductor part corresponding to a penetration part.

  In order to solve this problem, the electric motor according to the present invention is configured by alternately laminating a first steel plate and a second steel plate each having a slot opening corresponding to a slot in the axial direction. Here, the first steel plate has a penetrating portion penetrating between the peripheral edge portion of the first steel plate and the slot opening, and at least a part of the penetrating portion is divided by the adjacent second steel plate. Yes.

  According to the present invention, at least a part of the through portion in the first steel plate is divided by the adjacent second steel plate. Therefore, since the current path of the eddy current has a structure in which the conductor and the second steel plate are repeated, the current path is divided and the eddy current does not easily flow. As a result, there is no need to process the conductor portion corresponding to the penetrating portion, and Joule loss can be effectively suppressed.

Explanatory drawing which shows typically the principal part of the electric motor concerning 1st Embodiment. The perspective view which shows the principal part of a rotor typically The perspective view which shows the principal part of a 1st steel plate typically The perspective view which shows typically the principal part of a 2nd steel plate. Top view showing first steel plate and second steel plate The perspective view which shows typically the modification of the rotor which concerns on 1st Embodiment. Top view showing another form of the first steel plate Top view showing another form of the first steel plate The perspective view which shows typically the structure of the rotor about the electric motor which concerns on 2nd Embodiment. The perspective view which shows typically the structure of the rotor about the electric motor which concerns on 3rd Embodiment.

(First embodiment)
FIG. 1 is an explanatory diagram schematically showing a main part of the electric motor 1 according to the first embodiment. The electric motor 1 according to the present embodiment is a squirrel-cage induction motor, and is configured as a radial gap inner rotor type. The electric motor 1 includes a stator (stator) 2 having a ring-shaped cross section and a rotor (movable element) 3 connected to a shaft (not shown). The rotor 3 is disposed on the inner peripheral side of the stator 2. Arranged through an air gap.

  The stator 2 is configured by laminating a plurality of steel plates such as electromagnetic steel plates in the axial direction. The stator 2 has a plurality of stator teeth (not shown) (not shown), and the individual stator teeth are arranged at equal intervals along the circumferential direction on the inner peripheral side of the cylindrical back yoke portion. It has a prominent appearance. A stator winding is wound around each stator tooth via an insulator (insulating member).

  The stator 2 is stored inside the stator case 7 by being fitted to the cylindrical stator case 7 using a method such as shrink fitting. Thereby, the stator 2 is fixedly held by the stator case 7 in a state where an external force is applied as a whole from the outer peripheral side in the entire circumferential direction.

  FIG. 2 is a perspective view schematically showing a main part of the rotor 3. The rotor 3 is mainly composed of a rotor core 4 and a shaft is fitted at the center thereof. A plurality of hollow slots 4a extending in the axial direction are formed in the rotor core 4 along the circumferential direction. For example, a conductive material is cast into each slot 4a, so that the rotor bar A (conductor) 5 is formed.

  The rotor core 4 is configured by laminating a plurality of steel plates such as electromagnetic steel plates in the axial direction. Specifically, the rotor core 4 is configured by alternately laminating first steel plates 6 and second steel plates 7 in the axial direction.

  FIG. 3 is a perspective view schematically showing a main part of the first steel plate 6. The first steel plate 6 is a steel plate (magnetic steel plate) having a predetermined shape corresponding to the rotor core 4. The first steel plate 6 is integrally formed with a slot opening 6a corresponding to the shape of the slot 4a and a through portion 6b penetrating between the peripheral edge portion 6c of the first steel plate 6 and the slot opening 6a. . A plurality of slot openings 6a and penetrating portions 6b are formed corresponding to the number and position of the slots 4a. In the present embodiment, all the slots existing in the circumferential direction are set to have the same shape.

The slot opening 6a in the first steel plate 6 is configured to be line-symmetric (laterally symmetric) with respect to the slot center Cs. On the other hand, the penetrating portion 6b in the first steel plate 6 is disposed at a position shifted from the slot center Cs, and the overall opening shape including the slot opening 6a and the penetrating portion 6b is asymmetric with respect to the slot center Cs. It is configured. Specifically, the first penetration 6
b is arranged at a position shifted in one of the left and right directions (for example, the right direction shown in FIGS. 2 and 3) with respect to the slot center Cs. In this embodiment, the edge portion of the steel plate 6 defining the through-hole 6b is It is set to coincide with the slot center Cs.

  FIG. 4 is a perspective view schematically showing a main part of the second steel plate 7. Similar to the first steel plate 6, the second steel plate 7 is a steel plate (magnetic steel plate) having a predetermined shape corresponding to the rotor core 4. The second steel plate 7 is integrally formed with a slot opening 7a corresponding to the shape of the slot 4a and a through portion 7b penetrating between the peripheral edge portion 7c of the second steel plate 7 and the slot opening 7a. . A plurality of slot openings 7a and penetrating portions 7b are formed corresponding to the number and positions of the slots 4a. In the present embodiment, all the slots existing in the circumferential direction are set to have the same shape.

  The slot opening 6a in the second steel plate 7 is configured to be line symmetric (laterally symmetric) with respect to the slot center Cs. On the other hand, the penetrating portion 7b in the second steel plate 7 is disposed at a position shifted from the slot center Cs, and the overall opening shape including the slot opening 7a and the penetrating portion 7b is asymmetric with respect to the slot center Cs. It is configured. Specifically, the second penetrating portion 7b is disposed at a position shifted in the left and right other directions (for example, the left direction shown in FIGS. 2 and 4) with respect to the slot center Cs. The edge portion of the steel plate 7 defining 7b is set to coincide with the slot center Cs.

  In the rotor core 4 in which the first steel plates 6 and the second steel plates 7 are alternately stacked, the through portions 6b and 7b constitute a space that leads to the slot 4a. And the penetration part 6b in the 1st steel plate 6 and the penetration part 7b in the 2nd steel plate 7 are disperse | distributed and arrange | positioned at the position which becomes alternate on the boundary of the slot center Cs. In other words, when viewed along the axial direction, the through portion 6b in the first steel plate 6 is divided by the adjacent second steel plate 7, and the through portion 7b in the second steel plate 7 is adjacent to the first first steel plate 6. The steel plate 6 is divided.

  The rotor core 4 having such a configuration is created by alternately laminating the first steel plates 6 and the second steel plates 7. Here, the 1st steel plate 6 and the 2nd steel plate 7 can also be formed as an independent steel plate, respectively. However, if the slot openings 6a and 7a and the penetrating portions 6b and 7b shown in the present embodiment are used, the first steel plate 6 (see FIG. 5A) is the second when viewed from the back side. This corresponds to the shape of the steel plate 7 (see FIG. 5B). Accordingly, a steel plate corresponding to one of the shapes of the first steel plate 6 and the second steel plate 7 is prepared, and the steel plates are sequentially laminated one by one while reversing the front and back, so that the rotor core 4 described above is obtained. Can be created.

As described above, in the present embodiment, the electric motor 1 includes the stator 2 and the hollow slot 4a that is disposed on the inner peripheral side of the stator 2 via the air gap and extends in the axial direction along the circumferential direction. And a plurality of rotors 3 formed. The rotor 3 is configured by alternately laminating first steel plates 6 and second steel plates 7 each having slot openings 6a and 7a corresponding to the slots 4a in the axial direction. The first steel plate 6 has a through portion 6b penetrating between the peripheral edge portion 6c of the first steel plate 6 and the slot opening 6a, and the opening shape including the slot opening 6a and the through portion 6b is formed at the slot center Cs. It is asymmetrically configured. The second steel plate 7 has a through portion 7b penetrating between the peripheral edge portion 7c of the second steel plate 7 and the slot opening 7a, and the opening shape including the slot opening 7a and the through portion 7b is the center of the slot. It is asymmetric with respect to Cs. And the penetration part 6b in the 1st steel plate 6 and the penetration part 7b in the 2nd steel plate 7 are the relationship which turns alternately on the boundary of the slot center Cs, and the edge of the steel plates 6 and 7 which make the penetration parts 6b and 7b The portions are arranged in a relationship that coincides with the slot center Cs. Thereby, the penetration part 6b in the 1st steel plate 6 is divided by the adjacent 2nd steel plate 7, and the penetration part 7b in the 2nd steel plate 7 is divided by the adjacent 1st steel plate 6. It becomes.

  Here, the rotor 3 according to the present embodiment is compared with a rotor in which electromagnetic steel sheets in which the opening shape including the slot opening and the through portion is line-symmetric with respect to the slot center Cs are laminated. In the rotor according to the comparative example, when the rotor rotates, slot harmonic magnetic flux is generated in the rotor, and harmonic current flows in a closed circuit formed by the rotor bar and the end ring portion. As a result, a large Joule loss occurs at the tip of the rotor bar. On the other hand, in the rotor 3 according to the present embodiment, the current path of the eddy current has a structure in which the conductor (rotor bar 5) and the steel plates 6 and 7 are repeated, so that the current path is divided and is difficult to flow. As a result, Joule loss generated at the tip of the rotor bar 5 can be suppressed.

  According to such a configuration, the eddy current can be suppressed by dividing the individual through portions 6b and 7b by the adjacent steel plates 6 and 7 in the axial direction. Therefore, Joule loss can be effectively suppressed without processing the conductor portion corresponding to the through portions 6b and 7b.

  In the above-described embodiment, the edge portions of the steel plates 6 and 7 forming the through portions 6b and 7b are arranged so as to coincide with the slot center Cs. However, as shown in FIG. 6, the individual through portions 6b and 7b are set so that the edge portions of the steel plates 6 and 7 forming the through portions 6b and 7b completely overlap the adjacent steel plates 6 and 7. Also good.

  Further, the method of creating the rotor 3 is not limited to the above-described form. 7 and 8 are explanatory views showing the form of the first steel plate 6. In the 1st steel plate 6 shown in FIG. 7, the position of the penetration part 6b differs in right and left by the upper half and the lower half. In this case, the second steel plate 7 can be obtained by rotating the first steel plate 6 by 180 degrees. Therefore, the rotor core 4 can be created by forming the first steel plate 6 shown in FIG. 7 and rolling the steel plate 6 180 degrees. Moreover, in the 1st steel plate 6 shown in FIG. 8, the position of the penetration part 6b differs at right and left with a 90 degree period about a rotation direction. In this case, the second steel plate 7 can be obtained by rotating the first steel plate 6 by 90 degrees. Therefore, the rotor core 4 can be created by forming the first steel plate 6 shown in FIG. 8 and rolling the steel plate 6 90 degrees. In addition to this, a steel plate in which the positions of the through-holes 6b are different on the left and right sides for every divisor n of the number of slots in the rotation direction and the steel plate 6 is rolled 360 / n degrees to produce the rotor core 4. can do.

(Second Embodiment)
FIG. 9 is a perspective view schematically showing the configuration of the rotor 3 for the electric motor 1 according to the second embodiment. The rotor 3 according to the second embodiment is different from that of the first embodiment in the form of the second steel plate 7. In addition, description is abbreviate | omitted about the point which is common in 1st Embodiment, and it demonstrates focusing on difference below.

  The 2nd steel plate 7 which concerns on this embodiment is not formed with the penetration part 7b shown in 1st Embodiment, and the structure where the peripheral part 7c of the 2nd steel plate 7 and the slot opening 7b are not penetrated. It has become.

  In the rotor core 4 in which the first steel plates 6 and the second steel plates 7 are alternately laminated, as shown in FIG. 9, only the through portions 6b in the first steel plates 6 constitute a space that leads to the slots 4a. Even if it is such a form, when this is caught along an axial direction, the 1st penetration part 6b becomes the structure divided | segmented by the 2nd adjacent steel plate 7. FIG.

  According to such a configuration, as in the first embodiment, the Joule loss can be reduced and the strength of the rotor 3 can be increased because the through-hole 7b is not formed in the second steel plate 7. .

(Third embodiment)
FIG. 10 is a perspective view schematically showing the configuration of the rotor 3 for the electric motor 1 according to the third embodiment. The rotor 3 according to the third embodiment is different from that of the first embodiment in the form of the first steel plate 6 and the second steel plate 7. In addition, description is abbreviate | omitted about the point which is common in 1st Embodiment, and it demonstrates focusing on difference below.

  The through-hole 6b in the first steel plate 6 is disposed at a position shifted from the slot center Cs, as in the first embodiment, and the opening shape including the slot opening 6a and the through-hole 6b is the slot center Cs. It is asymmetrically configured. Specifically, the penetrating part 6b is arranged at a position shifted in one direction from the slot center Cs, and the penetrating part 6b is set to overlap the slot center Cs.

  Similar to the first embodiment, the penetrating portion 7b in the second steel plate 6 is disposed at a position shifted from the slot center Cs, and the opening shape including the slot opening 7a and the penetrating portion 7b is the slot center Cs. It is asymmetrically configured. Specifically, the penetrating part 7b is arranged at a position shifted in the other direction from the slot center Cs, and the penetrating part 7b is set to overlap the slot center Cs.

  In the rotor core 4 in which the first steel plates 6 and the second steel plates 7 are alternately stacked, as shown in FIG. 10, the through portions 6b and 7b constitute a through space that leads to the slot 4a. And the 1st penetration part 6b and the 2nd penetration part 7b are disperse | distributed and arrange | positioned in the position which becomes alternate on the boundary of the slot center Cs. When viewed in the axial direction, the penetrating portion 6b in the first steel plate 6 and the penetrating portion 7b in the second steel plate 7 have a relationship in which the adjacent penetrating portions 6b and 7b communicate with each other in the axial direction. A part of the through portion 6 b is divided by the adjacent second steel plate 7, and a part of the second through portion 7 b is divided by the adjacent first steel plate 6.

  When the edge portions of the steel plates 6 and 7 forming the through portions 6b and 7b are overlapped with the adjacent steel plates 6 and 7, it may cause a magnetic flux short circuit (leakage magnetic flux) and may cause a torque reduction. . On the other hand, when the range in which the adjacent penetrating portions 6b and 7b communicate in the axial direction becomes wider in the circumferential direction, the steel plate portion that blocks the rotor bar 5 decreases, so that the effect of blocking eddy currents may be reduced. However, according to a study using simulation or the like, since the current flows through the end of the slot 4a, the loss reduction effect is maintained even if the central portion is only a conductor. Thereby, improvement in torque can be expected while reducing Joule loss.

  As shown in the second and third embodiments, the rotor according to the present invention only needs to be divided by a second steel plate adjacent to at least a part of the penetrating portion in the first steel plate. . Thereby, since the current path of the eddy current has a structure in which the conductor (rotor bar) and the second steel plate are repeated, the current path is divided and the structure does not flow easily. As a result, the eddy current that causes Joule loss can be suppressed without processing the conductor portion corresponding to the penetrating portion of the rotor bar.

  Moreover, in the rotor 3, the adjacent 1st steel plate 6 and the 2nd steel plate 7 may be skewed. Thereby, the characteristic of the electric motor 1 can be improved while suppressing Joule loss.

  As mentioned above, although the electric motor concerning embodiment of this invention was demonstrated, it cannot be overemphasized that a various deformation | transformation is possible for this invention within the scope of the invention, without being limited to embodiment mentioned above.

DESCRIPTION OF SYMBOLS 1 Electric motor 2 Stator 3 Rotor 4 Rotor core 4a Slot 5 Rotor bar 6 1st steel plate 6a Slot opening 6b Through part 6c Peripheral part 7 2nd steel plate 7a Slot opening 7b Through part 7c Peripheral part

Claims (5)

A stator,
A movable element that is disposed on the inner peripheral side of the stator via an air gap and that has a plurality of hollow slots extending in the axial direction along the circumferential direction;
The mover is configured by alternately laminating a first steel plate and a second steel plate each having a slot opening corresponding to the slot in the axial direction,
The first steel plate has a penetrating portion penetrating between a peripheral edge portion of the first steel plate and the slot opening, and at least a part of the penetrating portion is divided by the adjacent second steel plate. An electric motor characterized by that. The second steel plate has a penetrating portion penetrating between a peripheral edge portion of the second steel plate and the slot opening,
The first steel plate and the second steel plate are configured such that an opening shape including the slot opening and the penetrating portion is asymmetric with respect to the slot center,
2. The electric motor according to claim 1, wherein the penetrating portion in the first steel plate and the penetrating portion in the second steel plate are arranged in a staggered relationship with respect to the slot center. .   2. The electric motor according to claim 1, wherein the second steel plate is configured not to penetrate between a peripheral edge portion of the second steel plate and the slot opening.   The said penetration part in the said 1st steel plate and the said penetration part in the said 2nd steel plate are arrange | positioned in the relationship which the said penetration part adjacent communicates in an axial direction, It is described in Claim 2 characterized by the above-mentioned. Electric motor.   5. The electric motor according to claim 1, wherein the movable element has a skew between a first steel plate and a second steel plate that are adjacent to each other. 6.

Images