JP4655646B2 - Permanent magnet embedded motor - Google Patents

Description

  The present invention relates to a small-sized and high-efficiency motor such as a compressor, an electric vehicle, a hybrid vehicle, and a fuel cell vehicle, which require a small-sized and high-efficiency characteristic particularly in a permanent magnet embedded motor.

  In recent years, awareness of coexistence with the global environment and energy saving has increased, and electric motors mounted on electric devices such as compressors used in air conditioners and refrigerators, electric motors mounted on electric vehicles, hybrid vehicles, fuel cell vehicles, etc. Even small size and high efficiency are required.

  Generally, the stator winding axial length L2 of a motor having a stator winding arranged in a stator and having a rotor in the radial direction via a magnetic gap is effective as a stator core axial length L1 as a magnetic path. In addition, the length of the stator winding end, that is, the so-called coil end height is required. On the other hand, the rotor core axial length of the rotor without the stator winding is a portion that is effective as a magnetic path opposite to the stator core via the magnetic gap, and is the axial direction of the stator core and the rotor core. The length is almost equal. Therefore, the total length L2 of the stator tends to be longer than the total length of the rotor.

  It is effective to increase the magnetic flux of the permanent magnet interlinked from the rotor to the stator to increase the torque of the electric motor using the permanent magnet, and effectively use the space generated by the difference between the total length L2 of the stator and the total length of the rotor. If it can be increased, the motor can be shortened accordingly, and a small high-efficiency motor can be realized.

FIG. 10 shows a longitudinal sectional view of a conventional permanent magnet embedded electric motor. 101 denotes a rotor, 102 denotes a stator, and 104 denotes a permanent magnet. Reference numerals 110a and 110b denote overhang portions, which overhang at both ends of the stator core axial length L1. Reference numeral 109 denotes a stator winding. The length of the rotor core in the axial direction is longer than the axial length L2 of the stator core, and the axial length of the permanent magnet also overhangs, thereby increasing the magnetic flux and increasing torque (for example, Patent Document 1). reference).
Japanese Patent Laid-Open No. 10-191585

  FIG. 11 is a diagram illustrating an example of the effective magnetic flux and the overhang length of the permanent magnet motor. The effective magnetic flux can be increased by making the axial length of the rotor core longer than the axial length of the stator core. However, if the overhang is a certain length, the magnetic saturation of the outer periphery of the rotor core As a result, the effective magnetic flux amount is saturated, and even if the amount of magnet used is increased, the torque cannot be increased, and the motor cannot be reduced in size.

  The present invention solves such a conventional problem, and a first rotor is provided on an end face side of a first rotor core having a first permanent magnet facing the stator core via a gap. The outer periphery of the rotor core in the overhang portion is provided by having a second rotor core in which a second permanent magnet, which is magnetized in the axial direction so that the same magnetic pole as that of the iron core is located on the first rotor core side, is disposed. It is an object of the present invention to provide a permanent magnet embedded type electric motor that eliminates the influence of magnetic saturation in the section and is small and has high output and high efficiency.

In order to solve the above-described problems, the present invention provides a stator in which a plurality of teeth are radially formed with a circumferential interval between an annular yoke and a winding groove, and a small gap between the stator and the stator. In a motor provided with a rotor that generates a field with a permanent magnet embedded in a rotor core that is opposed and rotatably supported, a first permanent that faces the stator core via a gap A second permanent magnet that is magnetized in the axial direction so that the same magnetic pole as the magnetic pole on the outer periphery of the first rotor is located on the first rotor core side is disposed on the end face side of the first rotor core having a magnet. an interior permanent magnet electric motor having a second rotor, further the stator core and the first first short axis cross-section than the axial length of the rotor core in the rotor core which faces via an air gap 1st permanent magnet magnetized in the direction A first rotor core that is not provided with a permanent magnet provided with a lit, and an end face of the first rotor core corresponding to a range from the outer peripheral side to the inner diameter side of the first permanent magnet, have a second rotor the same magnetic poles as magnetic poles of the second permanent magnets that are axially magnetized to be a first rotor core disposed, further the number of poles P, the rotor outer diameter D, the 1 has a configuration in which the axial length A of a rotor core without a permanent magnet of the rotor core is A ≦ πD / 4P , and a permanent magnet embedded type in which a magnetic body is disposed on the rotor end face In the electric motor, the same magnetic pole as the outer peripheral part permanent-side magnetic pole of the first rotor is placed on the first rotor core side on the end face side of the first rotor core facing the stator core via a gap. the axial dimension between the magnetic poles of the second permanent magnets that are axially magnetized shorter than the axial dimension of the magnetic pole center, the permanent The axial dimension of the end face arranged magnetic stones are those axial dimension between the magnetic poles and being greater than the axial dimension of the central magnetic pole between the permanent magnet magnetic pole.

The first on the end face side of the rotor core, axial attachment so that the same magnetic poles as the magnetic poles of the rotor core and the rotor core having a first permanent magnet which faces through the stator core and the air gap A nonmagnetic material may be disposed on the outer periphery of the permanent magnet of the second rotor in which the magnetized second permanent magnet is disposed.

  By the above means, it is possible to eliminate the influence of magnetic saturation on the outer peripheral portion of the rotor core in the overhang portion, and to provide a small permanent magnet with a high output and high efficiency.

According to the present invention, by optimizing the axial dimension of the permanent magnet of the overhanging rotor and the axial dimension of the magnetic material disposed on the end face, the amount of magnetic flux can be greatly increased by further increasing the axial dimension. Thus, it is possible to provide a permanent magnet embedded type electric motor that is small and has high output and high efficiency.

The best mode for carrying out the present invention will be described in the following examples. Reference examples will also be described .
( Reference Example 1)

Reference Example 1 will be described with reference to the drawings.
Figure 1 is a first permanent magnet-embedded motor sectional view showing a reference example, a plan view of a permanent magnet-embedded motor illustrating a first reference example of FIG. 2 is the invention of the present invention. Reference numeral 2 denotes a stator, and a plurality of teeth are radially formed at intervals in the circumferential direction to become an annular yoke and a stator winding groove. In FIG. 2, the stator winding 3 is arranged in the winding groove of the stator. The axial length of the stator is L2, and the axial length of the stator core is L1. Rotor opposed through a gap in the portion L1 of the stator core, the first rotor core 4 having a first permanent magnet magnetized in the axial sectional direction, the first rotor core 4 The second rotor core 6 is provided with a second permanent magnet 7 which is magnetized in the axial direction so that the same magnetic pole as the first magnetic pole is located on the first rotor core side. A second rotor yoke 8 made of a magnetic material is provided outside the second rotor core. For the sake of explanation, FIG. 2 does not show the stator winding 3 and the second rotor yoke 8.

  As shown in FIG. 2, the second permanent magnet is disposed on the outer peripheral side core portion of the first permanent magnet at the first rotating core end face. The second permanent magnet is arranged such that the same magnetic pole as the magnetic pole of the first permanent magnet is axially magnetized so as to be on the first rotor core side. Therefore, the magnetic flux of the second permanent magnet flows directly to the outer periphery of the first permanent magnet of the first rotor core, and the outer periphery of the permanent magnet of the rotor core in the overhang portion seen in the conventional example. The effect of saturation of the effective magnetic flux due to magnetic saturation on the side can be eliminated, and a small-sized, high-power and high-efficiency permanent magnet embedded motor can be provided.

  Since the second rotor yoke 8 disposed on the rotor end surface forms a magnetic path with the adjacent second permanent magnet, the axial length of the rotor is slightly longer, but the magnetic flux can be increased. It is valid.

This reference example is an example of a 6-pole V-shaped magnet embedded magnet type motor, but the same effect can be obtained even when the number of poles is different, or when the magnet shape is a flat plate or an arc shape. The larger the axial area on the outer peripheral side of the permanent magnet of the first rotor core, the more effective means. Even if the arrangement of the second permanent magnet partially overlaps with the first permanent magnet, the second permanent magnet It suffices if the ratio of the axial cross-sectional area on the outer peripheral side of the permanent magnet of the first rotor core is large with respect to the axial cross-sectional area. The same effect can be obtained even if the second magnet is arranged only on one side, is not limited to all the magnetic poles, is arranged with one or more poles, or is composed of a single permanent magnet magnetized on a plurality of magnetic poles. can get.

FIG. 3 is a plan view of an embedded permanent magnet electric motor rotor showing another example of the first reference example of the present invention, and a part of the outer peripheral side of the permanent magnet 5 of the first rotor core. The second permanent magnet 7 is arranged at a position corresponding to the above, and the same effect can be obtained.
( Reference Example 2)

Figure 4 is a second permanent magnet-embedded motor sectional view showing a reference example of the present invention, FIG 5 is a rotor plan view of a permanent magnet-embedded motor illustrating a second exemplary embodiment of the present invention. Reference numeral 2 denotes a stator, and a plurality of teeth are radially formed at intervals in the circumferential direction to become an annular yoke and a stator winding groove. The axial length of the stator is L2, and the axial length of the stator core is L1. The rotor faces the L1 portion of the stator core via a gap, and includes a first rotor core 4 having a first permanent magnet magnetized in the axial cross-section direction, and the first rotor core 4. The second rotor core 6 is provided with a second permanent magnet 7 that is axially magnetized so that the same magnetic pole as the outer magnetic pole is located on the first rotor core side. A second rotor yoke 8 made of a magnetic material is provided outside the second rotor core. The above is the same as in Reference Example 1.

A first rotor core that faces through the stator core with a gap, a point where the first permanent magnets magnetized in a short axial cross-sectional direction than the axial length of the first rotor core and arranged Reference Different from Example 1. The rotor core 4 has axial length portions A1 and A2 without permanent magnets. A detailed description will be given of the axial length portions A1 and A2 having no permanent magnet in the rotor core 4 with reference to FIG. FIG. 5A is a half cross-sectional view of the rotor of this reference example. 5B, 5C, and 5D are cross-sectional views of the first rotor core 9 in which the permanent magnets 51, 52, and 53 in FIG. 5A are not disposed, respectively. For the sake of explanation, the first rotor core 9 where no permanent magnet is arranged is indicated by a cross line, the second permanent magnet 7 is indicated by an oblique line, and the position of the first permanent magnet 5 is indicated by a two-dot chain line.

  The second permanent magnet 7 is arranged with a large area not only on the outer peripheral side of the permanent magnet of the first rotor core 4 but also on the inner peripheral side. The magnetic flux of the second permanent magnet 7 magnetized in the axial direction generates more magnetic flux as the area of the axial direction in which the magnetic flux is generated is larger if the permanent magnet is the same material. In order to effectively guide the magnetic flux to the outer peripheral side of the permanent magnet 5 of the first rotor core, slits are provided at locations corresponding to the magnetic poles as shown in FIGS. 5 (b), (c), and (d). ing. Further, since the inner peripheral dimensions are different, a collar 11 made of a nonmagnetic material is used for the inner diameter.

Thus, by the 1st rotor core 9 which does not arrange | position a permanent magnet, the magnetic flux of the 2nd permanent magnet 7 is the outer periphery of the permanent magnet 5 of the 1st rotor core which opposes a stator core via a space | gap. Led to the side. Since this reference example has a structure that can effectively use the magnetic flux of the end face magnet having a larger axial cross section than that of Reference Example 1, it is possible to provide a smaller, high-power and high-efficiency permanent magnet embedded motor. Can do.

As shown in FIG. 5 (a), the configuration of the first rotor core without the permanent magnets uses a plurality of rotor cores having different shapes and guides the magnetic flux to the first rotor core. The number of types may be reduced to change in a stepped shape. In addition, by using a non-magnetic composite material for the slit portion corresponding to the position between the magnetic poles, or by using an adhesive or the like, the strength of the rotor can be increased and the high-speed rotation can be achieved with a small size and high output. A highly efficient embedded permanent magnet electric motor can be provided.
( Reference Example 3)

FIG. 7 is a schematic perspective view of a permanent magnet for explaining a third reference example of the present invention. FIG. 7A shows a permanent magnet magnetized in the axial cross-sectional direction used for the first rotor core facing the stator core via a gap. FIG.7 (b) shows the permanent magnet magnetized in the axial direction used for the 2nd rotor arrange | positioned at the 1st rotor core end surface. Here, the rotor radius is R, the rotor diameter is D, and the number of poles is P.

In Reference Example 2, the axial dimensions of the first rotor core in which no permanent magnet is arranged are indicated by A1 and A2. In this reference example, more preferable dimensions of A1 and A2 are described. The following is a schematic calculation of the magnetic flux of the permanent magnet. From FIG. 7A, when the axial length of the first permanent magnet is A, to maximize the magnetic flux of the permanent magnet, the area indicated by the cross line is maximized, which is proportional to 2RA. To do. That is, it is proportional to DA. However, the thickness of the magnet and the shaft diameter of the rotor are ignored.

  On the other hand, from FIG. 7B, in order to maximize the magnetic flux of the second permanent magnet magnetized in the axial direction, the area indicated by the cross line is maximized, which is proportional to πD ^ 2 / 4P. To do.

When these two types are equal, the magnetic flux of the second permanent magnet is almost equal to the magnetic flux when the first permanent magnet is in the range of the axial dimension A of the first rotor core where no permanent magnet is disposed. In some cases, by setting A ≦ πD / 4P , it is possible to provide a permanent magnet embedded type electric motor that is small in size and high in output with a small amount of magnets.

FIG. 8 is a partial view and a plan view of a permanent magnet embedded motor rotor showing an embodiment of the present invention. 8 (a) is 4 is the first rotor core having a permanent magnet which faces through the stator core with a gap, the same pole and the magnetic pole of the first rotor core on its face end a A second permanent magnet 7 that is axially magnetized so as to be on the side of the one rotor core is disposed. A second rotor yoke 8 made of a magnetic material is disposed on the end face. The second permanent magnet 7 is greater than the axial dimension 72 between the axial dimension 71 of the magnetic pole center pole, the second rotor yoke 8, the axial dimension 82 you corresponds to the magnetic pole center be equivalent between the magnetic poles The axial dimension 81 is smaller. Since securing the necessary dimension in the axial direction dimension 81 you equivalent between the magnetic poles of the rotor yoke without magnetic saturation of the rotor yoke, the rotor as compared with the case the axial dimensions shown in FIG. 8 (b) is a uniform The axial dimension can be shortened by X, and the increase in the axial dimension can be minimized. Although the axial dimension is slightly increased, the amount of magnetic flux can be significantly increased, and a small-sized, high-power and high-efficiency permanent magnet embedded motor can be provided. In addition, about the structure which abbreviate | omitted description in the present Example, it is the structure similar to the above-mentioned reference example .
( Reference Example 4 )

FIG. 9 is a plan view of a permanent magnet embedded motor rotor showing a fourth reference example of the present invention. The top view of the 2nd rotor core is shown, and the 2nd rotor yoke is not illustrated. The first permanent magnet is indicated by a two-dot chain line, 7 is a second permanent magnet by an oblique line, and 10 is a permanent magnet holding ring by a cross line. The permanent magnet holding ring 10 is made of non-magnetic material and prevents short-circuiting of the magnetic fluxes of adjacent magnetic poles. The second permanent magnet 7 may be fixed to the first rotor by adhesion or the like, but by using the permanent magnet holding ring 10 as in this reference example, it can be fixed more firmly, Reliability at high-speed rotation is improved, and a small, high-power and high-efficiency permanent magnet embedded motor that can rotate at higher speed can be provided.

In addition, the use of the rotor core by powder sintering increases the degree of freedom in the shape of the rotor core, and as in Reference Example 2, it is easy to optimally introduce the magnetic flux of the permanent magnet into the stator core. A small-sized, high-output and high-efficiency permanent magnet embedded motor can be provided.

  Moreover, by mounting the permanent magnet embedded electric motor of the present invention, a compressor, an electric vehicle, a hybrid vehicle, and a fuel cell vehicle can be contributed to small size and high efficiency.

  The present invention can realize a small, high-output, high-efficiency electric motor with a simple configuration, and thus is useful as a permanent magnet embedded electric motor for compressors, electric vehicles, hybrid vehicles, fuel cell vehicles, and the like.

The first permanent magnet-embedded motor sectional view showing a reference example The first permanent magnet-embedded motor plan view showing a reference example Plane view of embedded permanent magnet motor rotor showing another example of the first reference example Interior permanent magnet motor sectional view showing the second reference example Rotor plan view of a permanent magnet-embedded motor illustrating a second reference example Half-sectional view of a rotor illustrating a second reference example, and the rotor core cross section Schematic perspective view of a permanent magnet of a third reference example Partial view and plan view of a permanent magnet embedded type electric motor rotor showing an embodiment of the present invention Plane view of embedded permanent magnet motor rotor showing a fourth reference example Vertical section of a conventional permanent magnet embedded motor The figure which shows an example of the effective magnetic flux and overhang part length of a permanent magnet motor

DESCRIPTION OF SYMBOLS 1 Embedded permanent magnet motor 2 Stator 3 Stator winding 4 1st rotor 5 1st permanent magnet 6 2nd rotor 7 2nd permanent magnet 8 2nd rotor yoke 9 No permanent magnet is arrange | positioned First rotor core 10 Permanent magnet holding ring 11 Collar 101 made of non-magnetic material Rotor 102 Stator 104 Permanent magnet 109 Stator winding 110a, 110b Overhang portion

Claims (1)

A stator in which a plurality of teeth are radially formed at circumferential intervals to be an annular yoke and a winding groove, and a rotation that is rotatably held facing the stator through a slight gap. In an electric motor including a rotor that generates a magnetic field with a permanent magnet embedded in a core of the core, an end face side of the first rotor core having a first permanent magnet facing the stator core via a gap In addition, a permanent magnet embedded type having a second rotor in which a second permanent magnet, which is magnetized in the axial direction so that the same magnetic pole as the magnetic pole on the outer periphery of the first rotor is located on the first rotor core side, is disposed. A first permanent magnet, which is an electric motor and is magnetized in an axial cross-sectional direction shorter than an axial length of the first rotor core, on a first rotor core facing the stator core via a gap. Do not arrange permanent magnets with slits at locations corresponding to the gaps between the magnetic poles. The same magnetic pole as the magnetic pole of the first rotor core is applied to the end face of the first rotor core corresponding to the range from the outer peripheral side to the inner diameter side of the first rotor core. a second permanent magnet-embedded motor that having a rotor and the second permanent magnet is arranged which is axially magnetized to be the core side, further the number of poles P, the rotor outer diameter D, the 1 is an embedded permanent magnet electric motor having a configuration in which an axial length A of a rotor core without a permanent magnet of the rotor core is A ≦ πD / 4P , and a magnetic body is disposed on the end face of the rotor in the permanent magnet-embedded motor,
The end face of the first rotor core that faces through the stator core with a gap, a is axially magnetized to the same magnetic pole as the first rotor pole becomes the first rotor core 2 of shorter than the axial dimension axial dimension of the magnetic pole center between the magnetic poles of the permanent magnets, the axial dimension of said arranged on the end face of the permanent magnet magnetic material, between the axial dimension is the permanent magnet magnetic pole between the magnetic poles permanent magnet-embedded motor you being greater than the axial dimension of the magnetic pole center.

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