JP2018148675A - Stator for rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To hinder occurrence of magnetic saturation in an annular stator.SOLUTION: A stator core 16 of a stator 12 has: an annular yoke 20; and a plurality of teeth 22 provided on an inner peripheral surface of the yoke 20 such that they project at a plurality of positions in a circumferential direction. A slot 24 is formed between adjacent teeth 22. A stator coil 18 is wound around the plurality of teeth 22. A plurality of projections 32 are provided on an outer peripheral surface of the yoke 20 and at a plurality of positions in a circumferential direction. The projections 32 are provided at positions on the outer peripheral surface and at the positions at least on the same straight line as the slot 24 corresponding to a portion higher than the other portion in terms of magnetic flux density in the yoke 20.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a stator for a rotating electrical machine, and more particularly to a technique for suppressing the occurrence of magnetic saturation in a stator.

  There is known a rotating electrical machine including a stator in which a plurality of phases of a stator coil is wound around an inner peripheral portion of an annular stator core. For example, in a three-phase rotating electrical machine, U-phase, V-phase, and W-phase stator coils are wound around a stator core.

  Patent Document 1 discloses a stator core having a linear portion formed on the outer peripheral surface. The straight portion is provided with a convex portion for suppressing the occurrence of magnetic saturation in the straight portion.

JP 2011-244451 A

  By the way, in an annular stator, since the distance from the slot to the outer peripheral surface of the stator core is uniform, the magnetic field distribution in the stator core is not taken into consideration, and the magnetic force distribution can be obtained only by providing a convex portion on the outer peripheral surface of the stator core. It is not always possible to suppress the occurrence of saturation.

  An object of the present invention is to suppress the occurrence of magnetic saturation in an annular stator.

  The invention according to claim 1 includes an annular yoke and a plurality of teeth provided at a plurality of positions in the circumferential direction on the inner peripheral surface of the yoke, and between adjacent teeth. A stator core formed with a slot; a stator coil wound around the plurality of teeth; and a plurality of protrusions provided at a plurality of circumferential positions on the outer peripheral surface of the yoke; Is a position on the outer peripheral surface, and is provided at a position on at least the same straight line of a slot corresponding to a portion where the magnetic flux density in the yoke is higher than that of the other portion. The stator.

  According to the present invention, it is possible to suppress the occurrence of magnetic saturation in an annular stator.

It is the figure which looked at the rotary electric machine which concerns on this embodiment from the axial direction. It is a figure which shows magnetic field distribution formed in the stator core.

  A rotating electrical machine according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a view of a rotating electrical machine 10 according to the present embodiment as viewed from the axial direction.

  The rotating electrical machine 10 is a synchronous motor with a magnet that is driven by a three-phase alternating current. The rotating electrical machine 10 is used as, for example, a motor that drives a hybrid vehicle, a generator, or a motor generator having both functions.

  The rotating electrical machine 10 roughly includes a stator 12 and a rotor 14. Stator 12 includes a stator core 16 fixed to the inside of a case (not shown) and a stator coil 18. The stator core 16 is configured in an annular shape by, for example, laminating a plurality of annular steel plates (for example, electromagnetic steel plates such as silicon steel plates) in the axial direction and integrally connected by caulking or the like. Instead of the laminated body of electromagnetic steel plates, the stator core 16 may be formed by integrally molding magnetic powder. The stator core 16 includes an annular yoke 20 and a plurality of teeth 22 that protrude in the radial direction on the inner peripheral surface of the yoke 20 and are arranged in the circumferential direction at predetermined intervals. A groove-like slot 24 is formed between adjacent teeth 22. Here, the “circumferential direction” is a circumferential direction around the central axis O of the stator 12, and the “radial direction” is the radial direction of the stator 12 orthogonal to the central axis O of the stator 12, The “direction” is the axial direction of the stator 12.

  The stator coil 18 is a three-phase distributed winding coil, and is formed by winding a phase winding across a plurality of teeth 22. FIG. 1 shows a part of the winding of the stator coil 18. Specifically, stator coil 18 includes a U-phase winding 18u, a V-phase winding 18v, and a W-phase winding 18w. Here, U, V, and W attached to each slot 24 indicate phases of windings wound around the slot 24.

  U-phase winding 18u includes a first U-phase winding 18u1 and a second U-phase winding 18u2. The first U-phase winding 18u1 is inserted into the slot 24 labeled U, and is inserted into the next slot 24 labeled U that extends in the circumferential direction from the inserted slot 24 and is separated by six slots. It is formed by repeating. Similarly, the second U-phase winding 18u2 is inserted into the slot 24 labeled U, and is inserted into the next slot 24 labeled U that extends circumferentially from the inserted slot 24 and is separated by 6 slots. It is formed by repeating this. The second U-phase winding 18u2 is inserted into the slot 24 adjacent in the circumferential direction with respect to the slot 24 into which the first U-phase winding 18u1 is inserted.

  V-phase winding 18v includes a first V-phase winding 18v1 and a second V-phase winding 18v2. The first V-phase winding 18v1 is inserted into the slot 24 labeled V, and is inserted into the next slot 24 labeled V that extends circumferentially from the inserted slot 24 and is separated by six slots. It is formed by repeating. Similarly, the second V-phase winding 18v2 is inserted into the slot 24 labeled V, and is inserted into the next slot 24 labeled V that extends circumferentially from the inserted slot 24 and is separated by 6 slots. It is formed by repeating this. Second V-phase winding 18v2 is inserted in slot 24 adjacent in the circumferential direction with respect to slot 24 in which first V-phase winding 18v1 is inserted.

  W-phase winding 18w includes a first W-phase winding 18w1 and a second W-phase winding 18w2. The first W-phase winding 18w1 is inserted into the slot 24 labeled W, and is inserted into the next slot 24 labeled W, extending in the circumferential direction from the inserted slot 24 and separated by six slots. It is formed by repeating. Similarly, the second W-phase winding 18w2 is inserted into the slot 24 labeled W, and is inserted into the next slot 24 labeled W extending in the circumferential direction from the inserted slot 24 and separated by six slots. It is formed by repeating this. Second W-phase winding 18w2 is inserted in slot 24 adjacent in the circumferential direction with respect to slot 24 in which first W-phase winding 18w1 is inserted.

  For example, a U-phase AC current is supplied to the U-phase winding 18u from a not-shown inverter connected to a DC power source via a U-phase cable. The V-phase winding 18v is supplied with a V-phase AC current that is 120 degrees different from the U-phase AC current from the inverter via the V-phase cable. The W-phase winding 18w is supplied with a W-phase purchase current that is 120 degrees out of phase with the U-phase and V-phase AC currents from the inverter via the W-phase cable.

  A rotor 14 is disposed inside the stator 12 in the radial direction. The rotor 14 includes a cylindrical rotor core 26 and a plurality of magnets 28 arranged at a plurality of circumferential positions in the rotor core 26. The magnet 28 is magnetized in the radial direction of the rotor 14, and the magnetization direction is reversed between the magnets 28 adjacent in the circumferential direction. Thereby, the N pole and the S pole are alternately formed on the outer circumferential surface of the rotor 14 in the circumferential direction. The rotor 14 is fixed in a state where the rotary shaft 30 is inserted inside, and both ends of the rotary shaft 30 are rotatably supported by a case (not shown).

  In the present embodiment, two slots 24 are formed per one pole and one phase. That is, the slots 24 are formed at a rate of two per phase with respect to the number of magnetic poles of the rotor 14. In the present embodiment, as an example, since the number of magnetic poles is eight and the number of phases is three, 48 (= 8 × 3 × 2) slots 24 are formed. The number of slots 24 is merely an example, and for example, multiples of slots 24 may be formed. Further, the number of slots 24 per pole / phase is merely an example, and one slot 24 per pole / phase may be formed.

  The stator 12 includes a plurality of convex portions 32 provided on the outer peripheral surface of the yoke 20 along the circumferential direction. The protrusions 32 are located on the outer peripheral surface of the yoke 20 every other slot 24, that is, at positions corresponding to the slots 24 with one slot 24 in between (positions on at least the same straight line in the radial direction of the slots 24). Is provided. The width in the circumferential direction of the convex portion 32 is, for example, a width greater than or equal to the width in the circumferential direction of the slot 24. The tip of the convex portion 32 has, for example, a linear or curved surface. The convex portion 32 may have a shape that becomes narrower toward the tip, or may have a shape with a constant width. The convex part 32 is comprised with the material same as the stator core 16, for example. In addition, at least some of the plurality of convex portions 32 are positions on the outer peripheral surface of the yoke 20, and the slots 24 corresponding to positions where the magnetic flux density is higher in the yoke 20 than other portions. It is provided at a position on at least the same straight line in the radial direction.

  Hereinafter, with reference to FIG. 2, the relationship between the magnetic field distribution formed in the stator core 16 and the installation position of the convex portion 32 will be described. FIG. 2 shows a part of the stator core 16 and represents the result of analyzing the magnetic field distribution of the stator core 16. The height of the magnetic flux density is expressed as shading. The magnetic flux density in the dark part is higher than the magnetic flux density in the thin part. The magnetic flux from the magnet 28 provided in the rotor 14 mainly flows in the yoke 20 through the teeth 22. In the stator core 16, if the convex portion 32 is not provided, the distance from the bottom portion of the slot 24 to the outer peripheral surface of the stator core 16 is shorter than the other portions of the stator core 16, so the portion where the slot 24 is formed It tends to run out of iron cores. Therefore, the portion of the yoke 20 corresponding to the slot 24 (the portion on the same straight line in the radial direction of the slot 24) is more likely to saturate the magnetic flux than the other portion of the yoke 20. In the example shown in FIG. 2, if the convex portion 32 is not provided, a portion on the same line in the radial direction of the slot 24 (slot 24 into which the V-phase winding 18 v is inserted) in the yoke 20. The magnetic flux density of 34 (the back portion of the slot 24, the portion surrounded by the broken line) is higher than the magnetic flux density of other portions, and the magnetic flux is saturated at the portion 34. That is, magnetic saturation occurs at the back of the slot 24. When the magnetic flux is saturated, a leakage magnetic flux is generated. When the leakage magnetic flux is increased, the exciting current of the coil is increased, so that the copper loss is increased and the efficiency of the rotating electrical machine is reduced.

  In the present embodiment, the convex portion 32 is provided at a position on the outer peripheral surface of the yoke 20 corresponding to a portion where the magnetic flux density is higher than the other portions and magnetic saturation can occur. In the example shown in FIG. 2, the convex portion 32 is provided at a position corresponding to the portion 34 where magnetic saturation can occur (at least on the same straight line in the radial direction of the portion 34). In the portion 34 where the magnetic saturation can occur, the distance from the bottom of the slot 24 to the outer peripheral surface of the stator core 16 (the tip surface of the convex portion 32) corresponds to the convex portion 32 by the thickness (height) of the convex portion 32. It becomes longer than the case where it is not provided. Therefore, compared with the case where the convex portion 32 is not provided, the magnetic flux is less likely to be saturated at the portion 34, and the occurrence of magnetic saturation can be suppressed.

  In the example shown in FIG. 1, every other slot 24 (with one slot 24 in between) protrudes to a position corresponding to the slot 24 (at least on the same straight line in the radial direction of the slot 24). Although the portion 32 is provided, this configuration is merely an example. The protrusions 32 do not have to be provided at every other slot 24 as long as the protrusions 32 are provided at positions corresponding to portions where the magnetic flux density is higher than other portions (portions where magnetic saturation can occur).

  DESCRIPTION OF SYMBOLS 10 Rotating electrical machine, 12 Stator, 14 Rotor, 16 Stator coil, 20 York, 22 Teeth, 24 slots, 26 Rotor core, 28 Magnet, 30 Rotating shaft, 32 Convex part.

Claims (1)

A stator core having an annular yoke and a plurality of teeth provided at a plurality of positions in the circumferential direction on the inner peripheral surface of the yoke, and a slot formed between adjacent teeth;
A stator coil wound around the plurality of teeth;
A plurality of convex portions provided at a plurality of circumferential positions on the outer peripheral surface of the yoke;
Have
The convex portion is a position on the outer peripheral surface, and is provided at a position on at least the same straight line of a slot corresponding to a portion where the magnetic flux density in the yoke is higher than other portions.
A stator for a rotating electrical machine.