JP5408277B2 - Induction motor and ceiling fan equipped with the same - Google Patents

Description

  The present invention relates to an induction motor provided with a stator in which a plurality of teeth are arranged radially, and more particularly to an induction motor that achieves high efficiency by reducing leakage magnetic flux in a slot opening.

  Conventionally, this type of induction motor employs a method in which an integral stator iron core is appropriately insulated and two-phase windings are wound concentrically. (For example, refer to Patent Document 1).

  Hereinafter, the induction motor will be described with reference to FIGS.

  As shown in the figure, the stator core 100 has a hole 101 for holding a hollow shaft in the center, a plurality of first tooth portions 102 in the vicinity of the outer periphery thereof, and a second tooth portion extending from there to the outer periphery. 103. The first tooth portion 102 and the second tooth portion 103 form a first slot 104 around which the A-phase winding 109 is wound, and a second slot 105 around which the B-phase winding 110 is wound. A first slot opening 106 and a second slot opening 107 are formed radially outward from the first slot 104 and the second slot 105.

  When a current is passed through the A-phase winding 109 and the B-phase winding 110, a magnetic flux is generated in the stator core 100 due to the magnetomotive force generated by the current. This magnetic flux interlinks with a rotor (not shown) to obtain a rotational torque, and the rotor rotates.

JP 2009-71913 A

  However, such a conventional induction motor has the following problems.

  Most of the magnetic flux flowing through the stator core 100 is interlinked with the rotor to produce the original action of the induction motor, but a part becomes a leakage magnetic flux and interlinks only with itself.

  As shown in FIG. 10, the width w1 of the first slot opening 106 and the width w2 of the second slot opening 107 are preferably smaller in the sense of reducing the excitation current. However, in this type of induction motor, the first slot is disposed on the inner peripheral side, and the radial dimension of the opening end surface of the first slot opening 106 becomes long. Therefore, the leakage reactance is increased, and the leakage magnetic flux 120 is generated not a little. When the leakage magnetic flux 120 increases, the loss of the induction motor increases and the efficiency decreases. Further, in order to improve the characteristics of the induction motor, it is necessary to wind many windings, which increases the material cost.

  In order to solve this problem, the magnetic flux leakage 120 can be reduced by increasing the width w1 of the first slot opening 106. However, since the width of the second tooth portion 103 is reduced and the magnetic flux density of the second tooth portion 103 is increased, magnetic saturation occurs in an extreme case, the loss of the induction motor is increased, and the efficiency is lowered. Therefore, there is a need for a stator core shape that fully considers the characteristics of the induction motor.

  The present invention solves such a conventional problem, and provides an induction motor that can reduce the leakage magnetic flux in the slot opening portion of the stator core and can achieve power saving and cost reduction. Objective.

  In order to achieve this object, the induction motor of the present invention is provided with a plurality of first slots for annularly providing the A-phase winding on the inner peripheral side, and a B-phase winding on the outer peripheral side of the first slot. An induction motor comprising a stator core provided with a plurality of second slots for applying a rotor, and a rotor rotatably attached to a side surface of the stator core, wherein the first of the stator core A first slot opening and a second slot opening that communicate radially from the slot and the second slot to the side surface of the stator core are provided, and an opening end face that faces each other in the circumferential direction of the first slot opening has an outer periphery The gap width W formed between the first slot and the first slot is set to 2.0 mm to 4.5 mm, the gap width w1 formed on the outermost peripheral portion is set to a range of 0.5 mm to 2.0 mm, and w1 <W , And the thereby is to achieve the intended purpose.

  According to the induction motor of the present invention, the first slot opening and the second slot opening that communicate radially from the first slot and the second slot of the stator core to the side surface of the stator core are provided, The opening end faces facing each other in the circumferential direction of the first slot opening have a gap width W of 2.0 mm to 4.5 mm formed between the outer periphery and the first slot, and a gap width formed in the outermost periphery. By setting w1 in the range of 0.5 mm to 2.0 mm and w1 <W, the leakage magnetic flux in the slot opening is reduced, so that a low-loss and high-efficiency induction motor is obtained, and By reducing the number of windings while maintaining a large rotational torque, the material cost can be reduced.

The side view of the ceiling fan carrying the induction motor of Embodiment 1 of this invention Sectional drawing showing the configuration of the induction motor Plan view with partial cross section of stator of same induction motor Enlarged view of the stator core of the induction motor The figure which shows the BH curve and magnetic permeability of an electromagnetic steel plate The figure which shows the relationship between the gap width W of a slot opening part, leakage reactance, and a tooth | gear part magnetic flux density The enlarged view of the stator core of the induction motor of Embodiment 2 of this invention Plan view showing a stator core of a conventional induction motor Top view of the stator after winding the winding of the induction motor Enlarged view of the stator core of the induction motor

  The induction motor according to claim 1 of the present invention is provided with a plurality of first slots that are annularly provided with an A-phase winding on the inner peripheral side, and a plurality of first slots that are provided with a B-phase winding on the outer peripheral side of the first slot. An induction motor comprising a stator core provided with two slots and a rotor rotatably attached to a side surface of the stator core, wherein the first slot and the second slot of the stator core A first slot opening and a second slot opening communicated radially from the slot to the side surface of the stator core are provided, and the opening end faces facing each other in the circumferential direction of the first slot opening are formed from the outer periphery to the first slot. The gap width W formed between the slots is set to 2.0 mm to 4.5 mm, the gap width w1 formed on the outermost peripheral portion is set to a range of 0.5 mm to 2.0 mm, and w1 <W. It has a configuration. As a result, the leakage magnetic flux in the slot opening is reduced, so that a low-loss and high-efficiency induction motor can be obtained, and the material cost can be reduced by reducing the number of windings while maintaining a large rotational torque. Can do.

  The outermost peripheral portion of the first slot opening may be provided with protrusions facing each other in the circumferential direction. As a result, the effective area of the side surface of the stator core facing the rotor increases, so that the excitation current can be reduced, and a low-loss and high-efficiency induction motor can be obtained.

  The gap width excluding the protrusions at the outermost peripheral portion of the first slot opening may be constant from the outer peripheral portion to the first slot. Thereby, since the leakage magnetic flux of a slot opening part is reduced, a low-loss and highly efficient induction motor can be obtained.

  Further, the gap width between the outer periphery of the first slot opening and the first slot may be increased at a predetermined angle. This increases the effect of reducing the leakage magnetic flux in the slot opening, resulting in a low-loss and high-efficiency induction motor, and reducing the material cost by reducing the number of windings while maintaining a large rotational torque. Can be achieved.

  The opening end surface of the first slot opening has a ratio W between a circumferential gap width w1 formed at the outermost peripheral portion and a circumferential gap width W formed between the outer peripheral portion and the first slot. / W1 may be set to a range of 1.0 to 9.0. This reduces the leakage flux in the slot opening without increasing the excitation current, resulting in a low-loss and high-efficiency induction motor and reducing the windings while maintaining a large rotational torque. The material cost can be reduced.

  Moreover, you may make it the structure that the outer diameter of the said stator core is set to 100 mm or more and 200 mm or less. As a result, the leakage magnetic flux in the slot opening is reduced while suppressing the maximum magnetic flux density of the tooth portion, so that an induction motor with low loss and high efficiency can be obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a side view of a ceiling fan on which the induction motor according to Embodiment 1 of the present invention is mounted. The ceiling fan 1 is a fan attached to the ceiling and is also called a ceiling fan. As shown in FIG. 1, an induction motor 2 is used as a drive source. The column 4 is fixed downward on the ceiling, and a hollow shaft 6 is connected to the column 4, and the induction motor 2 including the blade 3 is attached to the tip of the column 4. The induction motor 2 is covered with a main body cover 5 and an upper cover 11.

  FIG. 2 is a cross-sectional view showing the configuration of the induction motor. This induction motor 2 is an abduction type capacitor induction motor, and is fixed to the hollow shaft 6 with an A phase winding 8 (inner coil) and a B phase winding 9 (outer coil) via an insulator 7. The child iron core 16 is fixed. A rotor core 17 is provided around the hollow shaft 6 with a gap around the stator core 16. The rotor core 17 is press-fitted and held in the rotor cover 12 to form an abduction type rotor. The rotor cover 12 and the upper cover 11 are provided with bearing housing portions 13a and 13b, and are rotatably attached to the hollow shaft 6 via ball bearings 14a and 14b.

  FIG. 3 is a plan view with a partial cross section of the stator of the induction motor. The stator core 16 is formed by laminating a plurality of electromagnetic steel plates in the axial direction, and has a center hole 21 for press-fitting and holding the hollow shaft 6 in the center thereof, and is positioned annularly on the outer peripheral side of the center hole 21. A first tooth portion 22 on which the A-phase winding 8 is wound, and a second tooth portion 23 that extends further from the first tooth portion 22 in the outer peripheral direction and winds the B-phase winding 9; Formed. Moreover, the 1st slot 24 is formed by the adjacent 1st tooth part 22, and the 2nd slot 25 is formed between the 2nd tooth parts 23 extended in two steps. A first slot opening 26 and a second slot opening 27 are formed so as to communicate radially from the first slot 24 and the second slot 25 to the side surface of the stator core 16. Insulation is provided between the stator core 16 and the respective windings via an insulator 7 made of a resin molded product, thereby forming a stator 20.

  FIG. 4 is an enlarged view of the stator core of the induction motor. A rotor core (not shown) is disposed around the stator core 16 via a gap. When a current is passed through the A-phase winding 8 and the B-phase winding 9, a magnetic flux is generated in the stator core 16 due to the magnetomotive force caused by the current. This magnetic flux interlinks with the rotor to obtain rotational torque, and the rotor rotates.

  In this type of induction motor, the first slot 24 is disposed on the inner peripheral side, and the radial dimension of the opening end surface 32 of the first slot opening 26 is increased, so that the slot leakage reactance is increased, and the amount is small. A leakage magnetic flux 31 is generated. For this reason, the first slot opening 26 has a large gap width W formed between the outer periphery and the first slot 24.

  On the other hand, protrusions 33 facing each other in the circumferential direction are provided on the outermost peripheral portion of the first slot opening 26 to increase the effective area of the side surface of the stator core 16. Thereby, the exciting current of the stator 20 can be reduced, and a low-loss and high-efficiency induction motor can be obtained.

  That is, since the leakage magnetic flux in the first slot opening 26 can be reduced and the excitation current of the stator 20 can be reduced, an efficient induction motor can be obtained.

  FIG. 5 is a diagram showing a B (magnetic flux density) -H (magnetizing force) curve and magnetic permeability of an electromagnetic steel sheet. In this figure, the horizontal axis represents the magnetizing force H, and the vertical axis represents the magnetic flux density B on the left side and the magnetic permeability μ on the right side. If the coil current increases gradually from 0, the magnetizing force H increases. In the BH curve, the slope when H is small is large except when H is very small (region (a) in FIG. 5), and B increases greatly as H increases (in FIG. 5, (b)). region). However, when the inflection point of the BH curve is reached, the increase of B decreases, and when H increases, the slope of the curve suddenly decreases and B approaches a constant value (in FIG. 5, (c)). region). In this region, even if H increases, B hardly increases and magnetic saturation occurs. Further, the magnetic permeability μ is expressed by B / H and varies greatly depending on the magnetizing force and the magnetic flux density. The induction motor rotates the rotor by generating a rotating magnetic field. At this time, B and H vary around the region (b).

  As a result of various studies of conventional induction motors, in this type of induction motor, if the maximum magnetic flux density is designed to be below the inflection point of the BH curve, that is, near the maximum permeability, the increase in loss due to magnetic saturation and the efficiency increase. There is no reduction. Therefore, in FIG. 5, the maximum magnetic flux density was set to be 1.25 T or less.

  FIG. 6 is a diagram showing the relationship between the gap width W of the slot opening, leakage reactance, and tooth magnetic flux density. The present invention is to optimize the gap width W of the slot opening in consideration of leakage reactance and the magnetic flux density of the tooth portion. Here, selection of the gap width W of the slot opening will be described. The shape of each slot formed in the stator core 16 was not changed. In this figure, the horizontal axis represents the gap width W in the circumferential direction of the slot opening, the vertical axis represents the leakage reactance on the left side, and the second tooth portion 23 formed by forming the first slot opening 26 on the right side. Represents the magnetic flux density. As shown in the figure, when the gap width W of the slot opening is increased, the leakage reactance is reduced and the leakage magnetic flux can be reduced. Here, when it is aimed to reduce the leakage reactance by 15% or more from the conventional induction motor, it is appropriate to set the gap width W of the slot opening from 2.0 mm to 2.0 mm or more. It was judged.

  On the other hand, when the gap width W of the slot opening is widened, the tooth width is narrowed, so that the magnetic flux density of the tooth portion is increased. As described above, in order to suppress the maximum magnetic flux density to 1.25 T or less, it is appropriate to set the gap width W of the slot opening to 4.5 mm or less.

  Therefore, from the above relationship, it is appropriate to set the gap width W of the slot opening to a range of 2.0 mm to 4.5 mm, and leakage while suppressing the maximum magnetic flux density of the tooth portion to a predetermined value or less. Magnetic flux can be reduced. At the same time, if the outer diameter of the stator core 16 is smaller than 100 mm, the increase in the maximum magnetic flux density of the tooth portion becomes remarkable, and if it is larger than 200 mm, the maximum magnetic flux density of the tooth portion can be reduced relatively easily. Since the size is large and the cost cannot be reduced, it is preferable to set in the range of 100 mm to 200 mm.

  Thus, according to the induction motor 2 in Embodiment 1 of the present invention, since the leakage magnetic flux in the slot opening is reduced without increasing the excitation current, a low-loss and high-efficiency induction motor can be obtained. Then, the material cost can be reduced by reducing the number of windings while maintaining a large rotational torque.

  In addition, the ceiling fan has a large blade diameter and requires an induction motor that can hold the torque required to rotate the blade at a predetermined number of revolutions. Therefore, an abduction rotor and a plurality of teeth are arranged radially. A relatively large induction motor having a multipolar stator is used. In such a large induction motor, reduction of leakage magnetic flux at the slot opening is a big problem. Therefore, the induction motor according to the present embodiment is suitable for such a large induction motor, and a ceiling fan capable of achieving both power saving and cost reduction can be provided.

(Embodiment 2)
FIG. 7 is an enlarged view of the stator core of the induction motor according to the second embodiment of the present invention. In this figure, the difference from the first embodiment is that the opening end faces 32 facing each other in the circumferential direction of the first slot opening 26 are not parallel to each other, and are predetermined in the direction in which the gap width increases toward the first slot 24. This is a point configured with an angle θ. Also, the same components as those in FIG. 4 are denoted by the same reference numerals, and the description thereof is omitted. Moreover, since it is the same also about the block diagram which shows the ceiling fan of FIG. 1, and the induction motor 2 of FIG. 2, the description is abbreviate | omitted.

  In this case, since the first slot opening 26 expands at a predetermined angle θ, it is necessary to change the shapes of the second tooth portion 23 and the second slot 25, but the leakage magnetic flux 31 of the slot is transferred to the first slot 24. Since it is larger as it is closer, according to this configuration, the leakage reactance can be efficiently reduced.

  As described above, according to the induction motor 2 in Embodiment 2 of the present invention, the effect of reducing the leakage magnetic flux in the slot opening is increased, a low loss and high efficiency induction motor is obtained, and a large rotational torque is obtained. It is possible to reduce the material cost by reducing the number of windings while holding.

  In addition, although the induction motor 2 described in the first and second embodiments of the present invention has been described with a step provided only on the opening end surface of the first slot opening 26, the opening end surface of the second slot opening 27 is described. In the case where the radial dimension is long, the second slot opening 27 can also have the same shape.

  Since the induction motor according to the present invention enables power saving and cost reduction, it is useful as a drive motor for a ceiling fan or the like.

DESCRIPTION OF SYMBOLS 1 Ceiling fan 2 Induction motor 3 Blade | blade 4 Support | pillar 5 Main body cover 6 Hollow shaft 7 Insulator 8 A phase winding 9 B phase winding 10 Capacitor 11 Upper cover 12 Rotor cover 13a, 13b Bearing housing part 14a, 14b Ball bearing 15 rotation Child end ring part 16 Stator iron core 17 Rotor iron core 20 Stator 21 Center hole 22 1st tooth part 23 2nd tooth part 24 1st slot 25 2nd slot 26 1st slot opening part 27 2nd slot opening part 31 Leakage Magnetic flux 32 Open end face 33 Protrusion

Claims (7)

A stator core having a plurality of first slots provided with an A-phase winding on the inner peripheral side in an annular shape and a plurality of second slots provided with a B-phase winding on the outer peripheral side of the first slot, and the fixing An induction motor including a rotor that is rotatably mounted opposite to the side surface of the core,
A first slot opening and a second slot opening communicating radially from the first slot and the second slot of the stator core to the side surface of the stator core are provided, and the circumferential direction of the first slot opening The opening end faces facing each other have a gap width W of 2.0 mm to 4.5 mm formed between the outer periphery and the first slot, and a gap width w1 formed of the outermost periphery of 0.5 mm to 2.0 mm. An induction motor that is set to a range of w1 <W. The induction motor according to claim 1, wherein protrusions facing each other in a circumferential direction are provided on an outermost peripheral portion of the first slot opening. 3. The induction motor according to claim 1, wherein a gap width excluding the protrusion at the outermost peripheral portion of the first slot opening portion is constant from the outer peripheral portion to the first slot. The induction motor according to claim 1 or 2, wherein a gap width between an outer peripheral portion of the first slot opening and the first slot increases at a predetermined angle. The opening end face of the first slot opening has a ratio W / w1 between a circumferential gap width w1 formed at the outermost periphery and a circumferential gap width W formed between the outer periphery and the first slot. Is set in a range of 1.0 to 9.0, the induction motor according to any one of claims 1 to 4. The induction motor according to any one of claims 1 to 5, wherein an outer diameter of the stator core is set to 100 mm or more and 200 mm or less. A ceiling fan equipped with the induction motor according to any one of claims 1 to 6.

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