JP5679899B2 - Permanent magnet rotating electric machine - Google Patents

Description

  The present invention relates to a permanent magnet type rotating electrical machine used for wind power generation, for example, and relates to a permanent magnet type rotating electrical machine that is cooled by ventilation from one axial direction.

  In general, a permanent magnet type rotating electrical machine includes a rotor having a plurality of permanent magnets attached thereto, and a stator having a stator winding disposed on the stator core and arranged with a rotor and a gap. Yes. Note that a rotor arranged on the outer peripheral side of the stator is called an outer rotor type, and a rotor arranged on the inner peripheral side of the stator is called an inner rotor type.

  In such a permanent magnet type rotating electrical machine, in addition to heat generation due to the stator current, eddy current is generated in the permanent magnet due to the rotational drive of the rotor. When an eddy current flows through the permanent magnet, the permanent magnet generates heat, and irreversible demagnetization of the permanent magnet may occur. In addition, the escape of heat is the worst at the axial central portion of the rotor, and the magnet temperature at the axial central portion is the highest during rotational driving.

  Therefore, a permanent magnet type rotating electrical machine in which a plurality of permanent magnets are arranged in the circumferential direction of the rotor and each permanent magnet extends in the axial direction of the rotor, and each permanent magnet is arranged along the axial direction of the rotor. A permanent magnet type rotating electrical machine in which a high coercivity magnet is arranged at the center of the rotor and a low coercivity magnet is arranged at both ends of the rotor is proposed. (For example, refer to Patent Document 1).

  Also, instead of using a high coercive force magnet, the coercive force of a permanent magnet is locally improved by intensively diffusing heavy rare earth elements such as dysprosium and terbium at grain boundaries with respect to a low coercive force magnet. (For example, refer to Patent Document 2).

JP 2010-213516 A JP 2009-165349 A

However, the prior art has the following problems.
In the permanent magnet type rotating electrical machines described in Patent Documents 1 and 2, no consideration is given to the case where ventilation cooling is performed from one axial direction. That is, in the permanent magnet type rotating electrical machine cooled by ventilation from one axial direction, the temperature distribution is different from those described in Patent Documents 1 and 2.

  In a permanent magnet type rotating electrical machine that is cooled by ventilation from one axial direction, mainly heat generated by the stator winding current is cooled by ventilation, but the temperature on the leeward side is higher than the temperature on the windward side. Therefore, in the outer rotor type permanent magnet type rotating electrical machine, the stator outer diameter on the leeward side becomes larger than the stator outer diameter on the windward side due to the thermal expansion of the stator. That is, a gap provided between the rotor and the stator is smaller on the leeward side than on the leeward side.

  Thus, in the outer rotor type, when the gap between the rotor and the stator changes between the windward side and the leeward side, the magnetic flux density on the leeward side is higher than the magnetic flux density on the leeward side. At this time, an electromagnetic force is generated in the rotor in the average direction of the magnetic flux density, that is, in the ventilation direction. When electromagnetic force acts in the axial direction, the bearing may be damaged, and there is a problem that the reliability of the permanent magnet type rotating electrical machine is impaired. The influence of the electromagnetic force in the axial direction becomes more prominent as the device becomes larger.

  Further, in the inner rotor type permanent magnet type rotating electrical machine, when the temperature on the leeward side is higher than the temperature on the windward side, the leeward air gap is widened by the thermal expansion of the outer stator. Further, since the temperature of the leeward permanent magnet increases, the residual magnetic flux density (magnetic force) decreases. At this time, the magnetic flux density on the leeward side is higher than the magnetic flux density on the leeward side, so that electromagnetic force is generated in the direction opposite to the ventilation direction. When the electromagnetic force acts in the axial direction, the bearing may be damaged in the same manner as described above, and there is a problem that the reliability of the permanent magnet type rotating electrical machine is impaired.

  Further, in both the outer rotor type permanent magnet type rotating electrical machine and the inner rotor type permanent magnet type rotating electrical machine, when the temperature on the leeward side is higher than the windward side, the temperature of the permanent magnet on the leeward side causes the permanent There is a possibility that irreversible demagnetization of the magnet may occur, and there is also a problem that the reliability of the permanent magnet type rotating electrical machine is impaired.

  Note that if all permanent magnets are made to have high coercivity in accordance with the permanent magnets on the leeward side where the temperature becomes the highest, generally the residual magnetic flux density of the permanent magnets becomes weak, so the efficiency of the permanent magnet type rotating electrical machine decreases. . Further, since the high coercive force magnet contains a large amount of heavy rare earth elements, it is not desirable to make all permanent magnets high coercive force magnets from the viewpoint of saving rare earth.

  The present invention has been made to solve the above-described problems, and in a permanent magnet type rotating electrical machine that is ventilated and cooled from one axial direction, the reliability is impaired due to the temperature distribution in the axial direction. The object is to alleviate the phenomenon and obtain a highly reliable permanent magnet type rotating electrical machine.

A permanent magnet type rotating electrical machine according to the present invention is a permanent magnet type rotating electrical machine that is cooled by ventilation from one axial direction, and a plurality of permanent magnets are attached in a circumferential direction and an axial direction and arranged rotatably. A rotor, and a stator having a stator core and a stator winding provided on the stator core, with a gap on the inner peripheral side of the rotor, and a magnetic flux on the lee side when the rotor is stopped The density is configured to be lower than the magnetic flux density on the windward side, and the gap between the leeward rotor and the stator when the rotor is stopped is wider than the windward gap, or the rotor , The circumferential length of the leeward permanent magnet is shorter than the circumferential length of the leeward permanent magnet .

Moreover, the permanent magnet type rotating electrical machine according to the present invention is a permanent magnet type rotating electrical machine that is cooled by ventilation from one axial direction, and a plurality of permanent magnets are attached in the circumferential direction and the axial direction, and are arranged rotatably. And a stator having a stator core and a stator winding provided on the stator core, and having a gap on the outer peripheral side of the rotor. The magnetic flux density is configured to be higher than the leeward magnetic flux density, and the gap between the leeward rotor and the stator when the rotor is stopped is wider than the leeward gap or rotates. In the child, the circumferential length of the leeward permanent magnet is shorter than the circumferential length of the leeward permanent magnet .

The permanent magnet type rotating electrical machine according to the present invention is a permanent magnet type rotating electrical machine that is cooled by ventilation from one axial direction, and a plurality of permanent magnets are attached in the circumferential direction and the axial direction, and are arranged rotatably. And a stator having a stator core and a stator winding provided on the stator core, and having a gap on the inner peripheral side of the rotor. Is configured to be lower than the windward magnetic flux density, and when the rotor is stopped, the gap between the leeward rotor and the stator is wider than the windward gap, or in the rotor, the circumferential direction length of the downwind side of the permanent magnet, Ru der shorter than the circumferential length of the windward side of the permanent magnet. Thereby, the axial imbalance of the gap magnetic flux density can be reduced, and the electromagnetic force in the axial direction can be reduced .
Also, according to the permanent magnet type rotating electric machine according to the present invention, a permanent magnet type rotary electric machine which is ventilation cooling from one direction in the axial direction, it is mounted a plurality of permanent magnets in the circumferential direction and the axial direction, the rotation A rotor arranged freely, and a stator having a stator core and a stator winding provided on the stator core, with a gap disposed on the outer peripheral side of the rotor, and when the rotor is stopped, Whether the leeward magnetic flux density is higher than the leeward magnetic flux density, and whether the air gap between the leeward rotor and the stator is wider than the leeward air gap when the rotor is stopped. or in the rotor, the circumferential direction length of the upwind side of the permanent magnet, Ru der shorter than the circumferential length of the leeward side of the permanent magnet. Thereby, the axial imbalance of the gap magnetic flux density can be reduced, and the electromagnetic force in the axial direction can be reduced.
Therefore, in a permanent magnet type rotating electrical machine that is ventilated and cooled from one axial direction, it is possible to alleviate the phenomenon of impairing reliability due to temperature distribution in the axial direction and obtain a highly reliable permanent magnet rotating electrical machine. it can.

It is sectional drawing which shows the permanent magnet type rotary electric machine which concerns on Embodiment 1 of this invention. It is another sectional drawing which shows the permanent magnet type rotary electric machine which concerns on Embodiment 1 of this invention. It is a block diagram which shows the rotor of the permanent magnet type rotary electric machine which concerns on Embodiment 2 of this invention. It is sectional drawing which shows the permanent magnet type rotary electric machine which concerns on Embodiment 3 of this invention. It is sectional drawing which shows the permanent magnet type rotary electric machine which concerns on Embodiment 4 of this invention. It is sectional drawing which shows the permanent magnet type rotary electric machine which concerns on Embodiment 5 of this invention. It is a block diagram which shows the rotor of the permanent magnet type rotary electric machine which concerns on Embodiment 6 of this invention. It is sectional drawing which shows the permanent magnet type rotary electric machine which concerns on Embodiment 7 of this invention. It is sectional drawing which shows the permanent magnet type rotary electric machine which concerns on Embodiment 8 of this invention. It is another sectional view showing a permanent magnet type rotating electrical machine according to Embodiment 8 of the present invention. It is a block diagram which shows the permanent-magnet-type rotary electric machine which concerns on Embodiment 9 of this invention.

  Hereinafter, preferred embodiments of a permanent magnet type rotating electrical machine according to the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts will be described with the same reference numerals.

Embodiment 1 FIG.
1 is a cross-sectional view showing a permanent magnet type rotating electrical machine according to Embodiment 1 of the present invention. In FIG. 1, this permanent magnet type rotating electrical machine is of an outer rotor type that is ventilated and cooled from one axial direction (the right side in the figure). And a stator 20 arranged with a gap 30 on the inner peripheral side.

  The rotor 10 includes a rotor core 11 and permanent magnets 12a to 12e in which a plurality of permanent magnets are attached in the circumferential direction of the rotor core 11, and each of the plurality of permanent magnets is divided into a plurality of parts in the axial direction. Have. The stator 20 includes a stator core 21 and a stator winding 22 wound around a slot provided in the stator core 21. This permanent magnet type rotating electrical machine supplies rotational power or supplies generated power to the stator winding 22 by the magnetomotive force of the permanent magnet and the magnetomotive force generated by the current of the stator winding 22.

  Here, the permanent magnet type rotating electric machine is configured such that when the rotor 10 is stopped, the magnetic flux density on the leeward side is lower than the magnetic flux density on the leeward side. Specifically, the permanent magnets 12d and 12e on the leeward side are such that the gap 30 between the rotor 10 and the stator 20 on the leeward side when the rotor 10 is stopped is wider than the gap 30 on the leeward side. Is arranged on the outer peripheral side of the permanent magnets 12a to 12c. Instead of disposing the leeward permanent magnets 12d and 12e on the outer peripheral side, a plurality of permanent magnets having an inclined shape that widens the air gap 30 toward the leeward side are arranged in the circumferential direction of the rotor core 11. It may be attached.

  When current flows through the stator winding 22 wound around the stator core 21 and heat is generated, the temperature on the leeward side becomes higher than the temperature on the leeward side, which is fixed compared to when cold (when the rotor 10 is stopped). The core iron core 21 increases in the radial direction due to thermal elongation. Due to this thermal elongation, the air gap 30 provided between the rotor 10 and the stator 20 becomes smaller on the leeward side than on the leeward side.

  Therefore, the leeward side permanent magnets 12d and 12e are arranged on the outer peripheral side of the permanent magnets 12a to 12c, and the gap 30 between the leeward side rotor 10 and the stator 20 when the rotor 10 is stopped is defined as the windward side. By making the gap 30 wider than the gap 30, the non-uniformity of the gap 30 is corrected, the axial imbalance of the gap magnetic flux density is reduced, and the electromagnetic force in the axial direction is reduced. In addition, the permanent magnet type rotary electric machine shown in the following embodiments including this permanent magnet type rotary electric machine can be applied to a gearless permanent magnet type wind power generator.

As described above, according to Embodiment 1, it is a permanent magnet type rotating electrical machine that is cooled by ventilation from one axial direction, in which a plurality of permanent magnets are attached in the circumferential direction and are rotatably arranged. And a stator having a stator core and a stator winding provided on the stator core, the rotor on the leeward side when the rotor is stopped. The gap between the stator and the stator is wider than the gap on the windward side, and the magnetic flux density on the leeward side is lower than the magnetic flux density on the windward side. Thereby, the axial imbalance of the gap magnetic flux density can be reduced, and the electromagnetic force in the axial direction can be reduced.
Therefore, in a permanent magnet type rotating electrical machine that is ventilated and cooled from one axial direction, it is possible to alleviate the phenomenon of impairing reliability due to temperature distribution in the axial direction and obtain a highly reliable permanent magnet rotating electrical machine. it can.

  In the first embodiment, the configuration has been shown in which the leeward permanent magnets 12d and 12e are arranged on the outer peripheral side and the permanent magnets 12a to 12e have two gaps 30. However, the present invention is not limited to this, and as shown in FIG. 2, the permanent magnets 12 a to 12 e may have a multistage gap 30. In FIG. 2, the permanent magnet 12c is disposed on the outer peripheral side of the permanent magnets 12a and 12b, and the permanent magnets 12d and 12e are disposed on the outer peripheral side of the permanent magnet 12c. Since the thermal elongation of the stator core 21 is caused by the temperature gradient in the axial direction, the non-uniformity of the air gap 30 is further corrected by changing the air gap 30 in multiple stages according to this temperature gradient, and the axis of the air gap magnetic flux density is corrected. Directional imbalance is reduced, and axial electromagnetic force is reduced.

Embodiment 2. FIG.
FIG. 3 is a block diagram showing a rotor 10 of a permanent magnet type rotating electric machine according to Embodiment 2 of the present invention. In FIG. 3, a rotor 10 includes a rotor core 11 and a plurality of permanent magnets attached in the circumferential direction of the rotor core 11. Each of the plurality of permanent magnets is divided into a plurality of parts in the axial direction. ~ 12g.

  Here, the permanent magnet type rotating electric machine is configured such that when the rotor 10 is stopped, the magnetic flux density on the leeward side is lower than the magnetic flux density on the leeward side. Specifically, the rotor 10 is configured such that the circumferential length of the leeward permanent magnet 12g is shorter than the circumferential length of the leeward permanent magnets 12a to 12f. Other configurations are the same as those of the first embodiment described above, and thus description thereof is omitted. In addition, the permanent magnet having a short circumferential length may be configured in multiple stages instead of only one stage of the permanent magnet 12g.

  By configuring the circumferential length of the leeward permanent magnet 12g to be shorter than the circumferential length of the leeward permanent magnets 12a to 12f, the stator core 21 becomes larger in the radial direction due to thermal expansion. Even when the air gap 30 provided between the rotor 10 and the stator 20 becomes smaller on the leeward side, the magnetic force is made uniform in the axial direction, and the axial imbalance of the air gap magnetic flux density is reduced. The electromagnetic force in the axial direction is reduced.

As described above, according to the second embodiment, a permanent magnet type rotating electrical machine that is ventilated and cooled from one direction in the axial direction, in which a plurality of permanent magnets are attached in the circumferential direction and are rotatably arranged. And a stator having a stator core and a stator winding provided on the stator core, and having a space around the leeward side permanent magnet in the rotor. The direction length is made shorter than the circumferential direction length of the permanent magnet on the windward side, and the magnetic flux density on the leeward side is configured to be lower than the magnetic flux density on the windward side. Thereby, the axial imbalance of the gap magnetic flux density can be reduced, and the electromagnetic force in the axial direction can be reduced.
Therefore, in a permanent magnet type rotating electrical machine that is ventilated and cooled from one axial direction, it is possible to alleviate the phenomenon of impairing reliability due to temperature distribution in the axial direction and obtain a highly reliable permanent magnet rotating electrical machine. it can. In addition, the overall magnet usage can be reduced.

Embodiment 3 FIG.
4 is a sectional view showing a permanent magnet type rotating electric machine according to Embodiment 3 of the present invention. In FIG. 4, a rotor 10 includes a rotor core 11 and a plurality of permanent magnets attached in the circumferential direction of the rotor core 11, and each of the plurality of permanent magnets is divided into a plurality of parts in the axial direction. To 12e.

  Here, the permanent magnet type rotating electrical machine is configured such that the coercivity of the leeward permanent magnet 12e in the rotor 10 is larger than the coercivity of the leeward permanent magnets 12a to 12d. Specifically, a high coercivity magnet is attached as the leeward permanent magnet 12e, and low coercivity magnets are attached as the leeward permanent magnets 12a to 12d. Other configurations are the same as those of the first embodiment described above, and thus description thereof is omitted. Further, the high coercive force magnet is not limited to the single stage of the permanent magnet 12e alone, but may be configured in multiple stages in the axial direction, for example, with the leeward side as the leeward side magnet and the leeward side as the leeward side magnet.

  By attaching a high coercivity magnet as the leeward permanent magnet 12e and attaching a low coercivity magnet as the leeward permanent magnets 12a to 12d, the temperature in the axial direction against the irreversible demagnetization of the leeward permanent magnet 12e. The thermal demagnetization of the permanent magnet which becomes high can be reduced. Further, since the permanent magnets 12a to 12d on the leeward side have a higher residual magnetic flux density (magnetic force) than the permanent magnets 12e on the leeward side, it is possible to suppress a decrease in efficiency of the permanent magnet type rotating electrical machine to a minimum.

As described above, according to the third embodiment, the permanent magnet type rotating electrical machine is air-cooled from one axial direction, and a plurality of permanent magnets are attached in the circumferential direction. A rotor that is divided into a plurality of parts in the axial direction and is rotatably arranged, and a stator that is disposed with a gap on the inner peripheral side of the rotor and has a stator core and a stator winding provided on the stator core; In the rotor, a high coercivity magnet is attached to the leeward side, a low coercivity magnet is attached to the leeward side, and the coercivity of the leeward permanent magnet is larger than the coercivity of the leeward permanent magnet. It is comprised so that it may become. Thereby, the thermal demagnetization of the permanent magnet whose temperature increases in the axial direction can be reduced.
Therefore, in a permanent magnet type rotating electrical machine that is ventilated and cooled from one axial direction, it is possible to alleviate the phenomenon of impairing reliability due to temperature distribution in the axial direction and obtain a highly reliable permanent magnet rotating electrical machine. it can.

Embodiment 4 FIG.
FIG. 5 is a cross-sectional view showing a permanent magnet type rotating electric machine according to Embodiment 4 of the present invention. In FIG. 5, this permanent magnet type rotating electrical machine is of an inner rotor type that is cooled by ventilation from one axial direction (the right side in the figure), and a rotor 10 that is rotatably arranged, And a stator 20 disposed with a gap 30 on the outer peripheral side.

  The rotor 10 includes a rotor core 11 and permanent magnets 12a to 12e in which a plurality of permanent magnets are attached in the circumferential direction of the rotor core 11, and each of the plurality of permanent magnets is divided into a plurality of parts in the axial direction. Have. The stator 20 includes a stator core 21 and a stator winding 22 wound around a slot provided in the stator core 21. This permanent magnet type rotating electrical machine supplies rotational power or supplies generated power to the stator winding 22 by the magnetomotive force of the permanent magnet and the magnetomotive force generated by the current of the stator winding 22.

  Here, the permanent magnet type rotating electrical machine is configured such that the coercivity of the leeward permanent magnet 12e in the rotor 10 is larger than the coercivity of the leeward permanent magnets 12a to 12d. Specifically, a high coercivity magnet is attached as the leeward permanent magnet 12e, and low coercivity magnets are attached as the leeward permanent magnets 12a to 12d. The high coercive force magnet is not limited to the single stage of the permanent magnet 12e alone, but may be configured in multiple stages in the axial direction, for example, with the leeward side as the leeward side magnet and the leeward side as the leeward side magnet.

  By attaching a high coercivity magnet as the leeward permanent magnet 12e and attaching a low coercivity magnet as the leeward permanent magnets 12a to 12d, the temperature in the axial direction against the irreversible demagnetization of the leeward permanent magnet 12e. The thermal demagnetization of the permanent magnet which becomes high can be reduced. Further, since the permanent magnets 12a to 12d on the leeward side have a higher residual magnetic flux density (magnetic force) than the permanent magnets 12e on the leeward side, it is possible to suppress a decrease in efficiency of the permanent magnet type rotating electrical machine to a minimum.

As described above, according to the fourth embodiment, the permanent magnet type rotating electrical machine is air-cooled from one axial direction, and a plurality of permanent magnets are attached in the circumferential direction, and each of the plurality of permanent magnets is A rotor that is divided into a plurality of portions in the axial direction and is rotatably arranged, a stator that is disposed with a gap on the outer peripheral side of the rotor, and that has a stator core and a stator winding provided on the stator core; In the rotor, a high coercivity magnet is attached to the leeward side, a low coercivity magnet is attached to the leeward side, and the coercivity of the leeward permanent magnet is larger than the coercivity of the leeward permanent magnet. It is configured as follows. Thereby, the thermal demagnetization of the permanent magnet whose temperature increases in the axial direction can be reduced.
Therefore, in a permanent magnet type rotating electrical machine that is ventilated and cooled from one axial direction, it is possible to alleviate the phenomenon of impairing reliability due to temperature distribution in the axial direction and obtain a highly reliable permanent magnet rotating electrical machine. it can.

  In the third and fourth embodiments, in order to make the coercivity of the leeward permanent magnet 12e larger than the coercivity of the leeward permanent magnets 12a to 12d, a high coercivity magnet is used as the leeward permanent magnet 12e. It was explained that a low coercivity magnet was attached as the windward permanent magnets 12a to 12d. Here, the high coercive force magnet and the low coercive force magnet are the same type of permanent magnet, and the high coercive force magnet is a permanent magnet in which heavy rare earth elements are diffused intensively at the grain boundaries in the low coercive force magnet. Also good.

  At this time, the permanent magnet in which heavy rare earth elements are concentratedly diffused at the grain boundaries is not only one stage of the permanent magnet 12e. For example, from the center in the axial direction, the windward side is the leeward side magnet, and the leeward side is the leeward side. The magnet may be configured in multiple stages in the axial direction. Further, the same kind of permanent magnets may not be used in the axial direction.

  As a result, as in the third and fourth embodiments, thermal demagnetization of the permanent magnet that increases in temperature in the axial direction can be reduced with respect to the irreversible demagnetization of the leeward permanent magnet 12e. In addition, since the coercive force is increased by intensively diffusing heavy rare earth elements in the grain boundaries, the residual magnetic flux density (magnetic force) does not decrease and the efficiency of the permanent magnet type rotating electrical machine does not decrease.

Embodiment 5 FIG.
FIG. 6 is a sectional view showing a permanent magnet type rotating electrical machine according to Embodiment 5 of the present invention. In FIG. 6, a rotor 10 includes a rotor core 11 and a plurality of permanent magnets attached in the circumferential direction of the rotor core 11, and each of the plurality of permanent magnets divided into a plurality of parts in the axial direction. To 12e.

  Here, the permanent magnet type rotating electric machine is configured such that the magnetic flux density on the leeward side is higher than the magnetic flux density on the leeward side when the rotor 10 is stopped (when cold). Specifically, the permanent magnets 12d and 12e on the leeward side are arranged such that the gap 30 between the rotor 10 on the leeward side and the stator 20 when the rotor 10 is stopped becomes narrower than the gap 30 on the leeward side. Is arranged on the outer peripheral side of the permanent magnets 12a to 12c.

  Moreover, the permanent magnets 12d and 12e on the leeward side may be high coercivity magnets having a higher holding force than that on the leeward side. Instead of disposing the leeward permanent magnets 12d and 12e on the outer peripheral side, a plurality of permanent magnets having an inclined shape that narrows the gap 30 toward the leeward side are arranged in the circumferential direction of the rotor core 11. It may be attached. Since other configurations are the same as those of the fourth embodiment described above, description thereof is omitted.

  Even if the above-described irreversible demagnetization does not occur, the permanent magnet has a characteristic that the residual magnetic flux density (magnetic force) becomes weaker as the temperature is higher. Therefore, in the inner rotor type permanent magnet type rotating electrical machine, the gap magnetic flux density on the leeward side where the temperature is high is lower than that on the leeward side. Also, when the leeward permanent magnets 12d and 12e are high coercivity magnets, the residual magnetic flux density (magnetic force) of the leeward permanent magnet is weaker than that of the leeward permanent magnet. Furthermore, when the stator 20 swells to the outer peripheral side due to the thermal elongation of the stator 20, the gap may be widened on the leeward side where the temperature is high. As a result, the gap magnetic flux density is unbalanced in the axial direction, and electromagnetic force is generated in the direction opposite to the ventilation direction.

  Therefore, the leeward side permanent magnets 12d and 12e are arranged on the outer peripheral side of the permanent magnets 12a to 12c, and the gap 30 between the leeward side rotor 10 and the stator 20 when the rotor 10 is stopped is defined as the windward side. Even if the residual magnetic flux density (magnetic force) of the permanent magnet on the leeward side is affected by the temperature or is lowered by using a high coercive force magnet, the gap 30 is not narrowed. The uniformity is corrected, the axial imbalance of the air gap magnetic flux density is reduced, and the axial electromagnetic force is reduced.

As described above, according to the fifth embodiment, a permanent magnet type rotating electrical machine that is ventilated and cooled from one axial direction, in which a plurality of permanent magnets are attached in the circumferential direction and are rotatably arranged. And a stator having a stator core and a stator winding provided on the stator core, the rotor on the windward side when the rotor is stopped. The gap between the stator and the stator is wider than the gap on the leeward side, and the magnetic flux density on the leeward side is higher than the magnetic flux density on the leeward side. Thereby, the axial imbalance of the gap magnetic flux density can be reduced, and the electromagnetic force in the axial direction can be reduced.
Therefore, in a permanent magnet type rotating electrical machine that is ventilated and cooled from one axial direction, it is possible to alleviate the phenomenon of impairing reliability due to temperature distribution in the axial direction and obtain a highly reliable permanent magnet rotating electrical machine. it can.

  In the fifth embodiment, the configuration has been shown in which the leeward permanent magnets 12d and 12e are arranged on the outer peripheral side and the permanent magnets 12a to 12e take the two-stage gap 30. However, the present invention is not limited to this, and the permanent magnets 12a to 12e may have a multistage gap 30.

Embodiment 6 FIG.
FIG. 7 is a block diagram showing a rotor 10 of a permanent magnet type rotating electric machine according to Embodiment 6 of the present invention. In FIG. 7, a rotor 10 has a rotor core 11 and a plurality of permanent magnets attached in the circumferential direction of the rotor core 11, and each of the plurality of permanent magnets is divided into a plurality of parts in the axial direction. To 12d.

  Here, the permanent magnet type rotating electric machine is configured such that the magnetic flux density on the leeward side is higher than the magnetic flux density on the leeward side when the rotor 10 is stopped (when cold). Specifically, the rotor 10 is configured such that the circumferential length of the leeward permanent magnet 12a is shorter than the circumferential length of the leeward permanent magnets 12b to 12d. Other configurations are the same as those of the above-described fifth embodiment, and thus description thereof is omitted. In addition, the permanent magnet having a short circumferential length may be configured in multiple stages instead of only one stage of the permanent magnet 12a.

  By configuring the circumferential length of the leeward permanent magnet 12a to be shorter than the circumferential lengths of the leeward permanent magnets 12b to 12d, the residual magnetic flux density (magnetic force) of the leeward permanent magnet is set to a temperature. Even when the magnetic field is reduced by using a high coercive force magnet, the non-uniformity of the air gap 30 is corrected, the axial imbalance of the air gap magnetic flux density is reduced, and the axial electromagnetic force is reduced. Reduced.

As described above, according to the sixth embodiment, a permanent magnet type rotating electrical machine that is air-cooled from one axial direction, in which a plurality of permanent magnets are attached in the circumferential direction and are rotatably arranged. And a stator having a stator core and a stator winding provided on the stator core, and a circumferential direction of an upwind permanent magnet in the rotor. The length is shorter than the circumferential length of the leeward permanent magnet, and the leeward magnetic flux density is higher than the leeward magnetic flux density. Thereby, the axial imbalance of the gap magnetic flux density can be reduced, and the electromagnetic force in the axial direction can be reduced.
Therefore, in a permanent magnet type rotating electrical machine that is ventilated and cooled from one axial direction, it is possible to alleviate the phenomenon of impairing reliability due to temperature distribution in the axial direction and obtain a highly reliable permanent magnet rotating electrical machine. it can. In addition, the overall magnet usage can be reduced.

Embodiment 7 FIG.
FIG. 8 is a sectional view showing a permanent magnet type rotating electric machine according to Embodiment 7 of the present invention. In FIG. 8, a rotor 10 includes a rotor core 11 and a plurality of permanent magnets attached in the circumferential direction of the rotor core 11, and each of the plurality of permanent magnets is divided into a plurality of parts in the axial direction. To 12e.

  Here, the permanent magnet type rotating electric machine is configured such that the magnetic flux density on the leeward side is higher than the magnetic flux density on the leeward side when the rotor 10 is stopped (when cold). Specifically, the rotor 10 is configured such that the thickness of the leeward permanent magnet 12a is thinner than the thickness of the leeward permanent magnets 12b to 12e. Since other configurations are the same as those of the fourth embodiment described above, description thereof is omitted. Further, the thin permanent magnet may be configured in multiple stages instead of only one stage of the permanent magnet 12a.

  By configuring the leeward permanent magnet 12a to be thinner than the leeward permanent magnets 12b to 12e, the residual magnetic flux density (magnetic force) of the leeward permanent magnet is affected by temperature. Even if it is a case where it reduces by using a high coercive force magnet, the nonuniformity of the air gap 30 is corrected, the axial imbalance of the air gap magnetic flux density is reduced, and the electromagnetic force in the axial direction is reduced. In addition, since the temperature is lower on the leeward side than on the leeward side, there is little fear of irreversible demagnetization even if the thickness of the permanent magnet 12a is reduced, and the overall magnet usage can be reduced.

As described above, according to the seventh embodiment, the permanent magnet type rotating electrical machine is air-cooled from one axial direction, and a plurality of permanent magnets are attached in the circumferential direction, and each of the plurality of permanent magnets is A rotor that is divided into a plurality of portions in the axial direction and is rotatably arranged, a stator that is disposed with a gap on the outer peripheral side of the rotor, and that has a stator core and a stator winding provided on the stator core; In the rotor, the thickness of the leeward permanent magnet is made thinner than that of the leeward permanent magnet, and the coercivity of the leeward permanent magnet is larger than the coercivity of the leeward permanent magnet. It is configured as follows. Thereby, the thermal demagnetization of the permanent magnet whose temperature increases in the axial direction can be reduced.
Therefore, in a permanent magnet type rotating electrical machine that is ventilated and cooled from one axial direction, it is possible to alleviate the phenomenon of impairing reliability due to temperature distribution in the axial direction and obtain a highly reliable permanent magnet rotating electrical machine. it can. In addition, the overall magnet usage can be reduced.

  When the configuration of the seventh embodiment is applied to an outer rotor type permanent magnet type rotating electrical machine, even if the windward permanent magnet is thinned, the influence of thermal expansion cannot be avoided, but irreversible demagnetization From this point of view, the overall magnet usage can be reduced by thinning the windward permanent magnet having a low temperature.

Embodiment 8 FIG.
FIG. 9 is a cross-sectional view showing a permanent magnet type rotating electrical machine according to Embodiment 8 of the present invention. In FIG. 9, a rotor 10 has a rotor core 11 and a plurality of permanent magnets attached in the circumferential direction of the rotor core 11, and each of the plurality of permanent magnets is divided into a plurality of parts in the axial direction. To 12e.

  Here, the permanent magnet type rotating electrical machine is configured such that the axial length of the leeward permanent magnets 12d and 12e in the rotor 10 is shorter than the axial length of the leeward permanent magnets 12a to 12c. Has been. Other configurations are the same as those of the first embodiment described above, and thus description thereof is omitted. Further, the permanent magnet having a short axial length may be configured in multiple stages instead of the two stages of the permanent magnets 12d and 12e.

  When a rare earth sintered magnet is used as the permanent magnet, the permanent magnet itself has conductivity, so that an eddy current due to the harmonic magnetic flux from the stator 20 flows to the permanent magnet. The permanent magnet generates heat due to this eddy current. In a permanent magnet type rotating electrical machine that is cooled by ventilation from one axial direction, it is important to suppress the heat generation of the permanent magnet on the lee side of the permanent magnet on the windward side, and heat generation due to eddy current is also prevented on the leeward side. There is a need to.

  Here, as the axial length of the permanent magnet is shorter, the impedance of the eddy current circuit with respect to the amount of harmonic magnetic flux increases, so the eddy current generated in the permanent magnet decreases. However, if the axial length of all the permanent magnets is shortened, the work of the permanent magnet type rotating electrical machine may be complicated.

  Accordingly, the axial length of the leeward permanent magnets 12d and 12e is configured to be shorter than the axial length of the leeward permanent magnets 12a to 12c, thereby generating heat from the leeward permanent magnets 12d and 12e. It is possible to reduce the amount of heat generated from the permanent magnets 12a to 12c on the leeward side and to mitigate the temperature rise on the leeward side.

As described above, according to the eighth embodiment, in the rotor, the axial length of the leeward permanent magnet is shorter than the axial length of the leeward permanent magnet. Thereby, the eddy current loss on the high temperature side can be reduced and the temperature increase on the leeward side can be mitigated.
Therefore, in a permanent magnet type rotating electrical machine that is ventilated and cooled from one axial direction, it is possible to alleviate the phenomenon of impairing reliability due to temperature distribution in the axial direction and obtain a highly reliable permanent magnet rotating electrical machine. it can. In addition, the overall magnet usage can be reduced.

  In the eighth embodiment, the case where the permanent magnet type rotating electrical machine is of the outer rotor type has been described. However, the present invention is not limited to this, and the configuration of the eighth embodiment is configured as shown in FIG. The present invention may be applied to an outer rotor type permanent magnet type rotating electrical machine. In this case, the same effect as in the eighth embodiment can be obtained.

Embodiment 9 FIG.
FIG. 11 is a block diagram showing a rotor 10 of a permanent magnet type rotating electric machine according to Embodiment 9 of the present invention. In FIG. 11, a rotor 10 includes a rotor core 11 and a plurality of permanent magnets attached in the circumferential direction of the rotor core 11, and each of the plurality of permanent magnets divided into a plurality of parts in the axial direction. To 12d.

  Here, in the permanent magnet type rotating electrical machine, in the rotor 10, the permanent magnets 12a to 12d divided into a plurality in the axial direction are not arranged linearly in the axial direction, but are arranged in the permanent magnets 12a to 12d. On the other hand, skew is applied to each step in the circumferential direction, and the skew angle on the leeward side and the skew angle on the leeward side are configured to be different from each other.

  Generally, torque pulsation such as cogging torque can be reduced by applying skew. At this time, if the residual magnetic flux densities of all the permanent magnets in the axial direction are equal, in the case of a step skew as shown in FIG. 11 (FIG. 11 shows a two-step V-skew that wraps around the center. ), The number of poles Np, the number of skewed stages Nd, the number of stator slots Ns, and the least common multiple of Np and Ns is N. The stage skew angle is represented by 360 / N / Nd in mechanical angle.

  However, when air is cooled from one axial direction and temperature distribution occurs in the axial direction (when the residual magnetic flux density changes in the axial direction), or in the axial direction as shown in the first to eighth embodiments. If the type of permanent magnet is different between the windward side and the leeward side, or if the circumferential length, axial length or thickness is different and the residual magnetic flux density is different in the axial direction, all permanent magnets in the axial direction With a normal skew (360 / N / Nd), which shows that the residual magnetic flux density of the magnets is equal, it is difficult to effectively reduce the cogging torque.

  Therefore, in the rotor 10, the permanent magnets 12a to 12d are skewed step by step in the circumferential direction, and the cogging torque is changed so that the upwind skew angle and the leeward skew angle are different from each other. Can be effectively reduced.

As described above, according to the ninth embodiment, in the rotor, the permanent magnets divided into a plurality in the axial direction are not arranged linearly in the axial direction, but are skewed with respect to the permanent magnets. The leeward skew angle and the leeward skew angle are different from each other. Thereby, a cogging torque can be reduced effectively.
Therefore, in a permanent magnet type rotating electrical machine that is ventilated and cooled from one axial direction, it is possible to alleviate the phenomenon of impairing reliability due to temperature distribution in the axial direction and obtain a highly reliable permanent magnet rotating electrical machine. it can. In addition, the overall magnet usage can be reduced.

  In the ninth embodiment, FIG. 11 shows an example in which the stage skew is composed of two stages on the leeward side and two stages on the leeward side. However, the same effect can be obtained even when there are multiple stages. In the ninth embodiment, the case where the permanent magnet type rotating electrical machine is of the inner rotor type has been described. However, the present invention is not limited to this, and the configuration of the ninth embodiment is the outer rotor type permanent magnet type rotating electric machine. When applied to an electric machine, the same effect as in the eighth embodiment can be obtained.

  10 Rotor, 11 Rotor core, 12a-12g Permanent magnet, 20 Stator, 21 Stator core, 22 Stator winding, 30 Air gap.

Claims (12)

A permanent magnet type rotating electrical machine that is cooled by ventilation from one axial direction,
A rotor in which a plurality of permanent magnets are attached in the circumferential direction and arranged rotatably;
A stator having a gap on the inner peripheral side of the rotor, and having a stator core and a stator winding provided on the stator core, and
When the rotor is stopped, the leeward magnetic flux density is configured to be lower than the leeward magnetic flux density ,
A permanent magnet type rotating electrical machine , wherein a gap between the rotor on the leeward side and the stator when the rotor is stopped is wider than a gap on the leeward side . A permanent magnet type rotating electrical machine that is cooled by ventilation from one axial direction,
A rotor in which a plurality of permanent magnets are attached in the circumferential direction and arranged rotatably;
A stator having a gap on the inner peripheral side of the rotor, and having a stator core and a stator winding provided on the stator core, and
When the rotor is stopped, the leeward magnetic flux density is configured to be lower than the leeward magnetic flux density ,
In the rotor, the permanent magnet type rotating electrical machine is characterized in that a circumferential length of the leeward permanent magnet is shorter than a circumferential length of the leeward permanent magnet . The permanent magnet type rotating electrical machine according to claim 2 , wherein a gap between the rotor on the leeward side and the stator when the rotor is stopped is wider than a gap on the leeward side. A permanent magnet type rotating electrical machine that is cooled by ventilation from one axial direction,
A rotor in which a plurality of permanent magnets are attached in the circumferential direction and arranged rotatably;
A stator having a gap on the outer peripheral side of the rotor, and having a stator core and a stator winding provided on the stator core, and
When the rotor is stopped, the leeward magnetic flux density is configured to be higher than the leeward magnetic flux density ,
A permanent magnet type rotating electrical machine , wherein a gap between the rotor on the windward side and the stator when the rotor is stopped is wider than a gap on the leeward side . A permanent magnet type rotating electrical machine that is cooled by ventilation from one axial direction,
A rotor in which a plurality of permanent magnets are attached in the circumferential direction and arranged rotatably;
A stator having a gap on the outer peripheral side of the rotor, and having a stator core and a stator winding provided on the stator core, and
When the rotor is stopped, the leeward magnetic flux density is configured to be higher than the leeward magnetic flux density ,
In the rotor, the permanent magnet type rotating electric machine is characterized in that the circumferential length of the leeward permanent magnet is shorter than the circumferential length of the leeward permanent magnet . The permanent magnet type rotating electrical machine according to claim 5 , wherein a gap between the rotor on the windward side and the stator when the rotor is stopped is wider than a gap on the leeward side. Before SL plurality of permanent magnets, each being divided into a plurality in the axial direction,
Prior SL rotor, the coercive force of the downwind side of the permanent magnet, either be configured to be larger than the coercive force of the windward side of the permanent magnets from claim 1, wherein up to claim 6 The permanent magnet type rotating electrical machine according to item 1 . The permanent magnet type rotating electrical machine according to claim 7 , wherein a high coercivity magnet is attached to the leeward side and a low coercivity magnet is attached to the leeward side of the rotor. The permanent magnet rotating electric machine according to claim 8 , wherein the high coercivity magnet is a permanent magnet in which heavy rare earth elements are diffused intensively at grain boundaries in the low coercivity magnet. The permanent magnet type rotating electrical machine according to claim 7 , wherein in the rotor, the thickness of the permanent magnet on the leeward side is smaller than the thickness of the permanent magnet on the leeward side. 11. The rotor according to claim 1, wherein an axial length of the leeward permanent magnet is shorter than an axial length of the leeward permanent magnet in the rotor. Permanent magnet type rotating electric machine. In the rotor, each of the plurality of permanent magnets is divided into a plurality of portions in the axial direction, and skew is applied to the divided permanent magnets, and the skew angle on the leeward side and the skew angle on the leeward side are The permanent magnet type rotating electrical machine according to any one of claims 1 to 11, wherein the permanent magnet type rotating electrical machines are different from each other.

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