JP2015089149A - Multi-gap type rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent demagnetization of a magnet at a rotor magnetic pole end part without deteriorating motor performance, and to improve a demagnetization resistance of an inner magnet 9 to an outer magnet 10.SOLUTION: Counter-stator side surfaces of an inner magnet 9 and an outer magnet 10 are inclined so that magnet thicknesses P2 and P4 of respective magnetic pole end parts are gradually reduced from the center side in a circumferential direction toward a circumferential direction end. That is, a radial direction width of a rotor yoke 4d becomes larger (wider) gradually as it goes toward the circumferential direction end of an inner rotor magnetic pole and an outer rotor magnetic pole. Thereby, in the vicinity of the magnetic pole end part where a q-axis magnetic flux generating a reluctance torque and a d-axis magnetic flux generating a magnet torque are the most concentrated, magnetic saturation at the rotor yoke 4d can be suppressed. As a result, because magnetic leakage to the inner magnet 9 and the outer magnet 10 can be prevented, local demagnetization of the inner magnet 9 and the outer magnet 10 at the magnetic pole end part can be prevented.

Description

  The present invention can be applied to various uses such as industrial use and automobile use, and particularly relates to a multi-gap type rotating electrical machine suitable for use in a running motor of a hybrid car.

2. Description of the Related Art Conventionally, as a small and high-power motor, an IPM motor (magnet embedded motor) that can utilize reluctance torque that is an iron core attractive force in addition to magnet torque by a magnet is widely known. In this IPM motor, as shown in FIG. 8, there is a double stator type motor in which an inner stator 110 and an outer stator 120 are arranged on the inner diameter side and the outer diameter side of the rotor 100.
For example, in the double stator motor disclosed in Patent Document 1, an inner magnet 130 is embedded on the inner peripheral side of the rotor core 101 facing the inner stator 110, and an outer magnet 140 is embedded on the outer peripheral side, and adjacent to each other in the circumferential direction. An inner rotor salient pole 102 and an outer rotor salient pole 103 are formed between the magnet magnetic poles.

JP 2007-261342 A

However, the motor of Patent Document 1 has a problem in practical use for the following reasons.
a) Local demagnetization tends to occur at the permanent magnets (inner magnet 130, outer magnet 140) embedded in the rotor core 101, particularly at the magnetic pole ends (both ends in the circumferential direction).
b) In the case of a double stator type motor in which the inner stator 110 and the outer stator 120 are arranged inside and outside the rotor 100, the inner magnet 130 is more easily demagnetized than the outer magnet 140.

As a result of considering the above problems, the present inventor has found that there is the following root cause.
The largest factor of a) is that magnetic saturation is likely to occur in the rotor yoke where the magnetic flux of the inner magnetic circuit and the magnetic flux of the outer magnetic circuit merge and flow, so that magnetic leakage occurs inside the magnet, resulting in a large demagnetizing field in the magnet. It is in that it takes.
The reason why magnetic saturation is likely to occur is that the q-axis magnetic flux (see FIG. 9) that generates reluctance torque and the d-axis magnetic flux (see FIG. 10) that generates magnet torque are the most concentrated, as shown by thick arrows in FIG. This is because the rotor yoke width W is narrow in the vicinity of the end of the magnet magnetic pole.
Another reason for causing local demagnetization is that magnetic saturation is likely to occur in the rotor salient poles 102 and 103 between the magnetic poles, resulting in magnetic leakage. As a result, a large demagnetizing field is generated at the magnetic pole ends near the rotor salient poles. It is in hanging. The reason why the magnetic saturation is likely to occur is that the q-axis magnetic flux concentrates on the narrow rotor salient poles 102 and 103 between the magnetic poles as shown in FIG.

The factor of b) is that in the double stator motor, the inner magnetic circuit is more likely to cause magnetic saturation than the outer magnetic circuit, so that magnetic leakage occurs, and as a result, a large demagnetizing field is applied in the vicinity of the inner magnet 130. It is in. The reason why magnetic saturation is likely to occur is that the area occupied by the inner stator 110 disposed on the inner diameter side of the rotor 100 is smaller than the outer stator 120 disposed on the outer diameter side of the rotor 100. That is, if the slot area equivalent to that of the outer stator 120 is to be secured in the inner stator 110, the teeth width of the inner stator 110 must be reduced.
Here, the reason why magnet demagnetization occurs in the first place is that the demagnetizing field is larger than the magnet holding force (proportional to the magnet thickness). Therefore, it is effective to increase the magnet thickness as a countermeasure against the magnet demagnetization. However, if this method is adopted in a double stator type motor, the rotor yoke or the back yoke of the inner or outer stator becomes narrow, resulting in magnetic saturation and a reduction in motor performance.

  The present invention has been made on the basis of the above circumstances. As a first object, it is possible to prevent demagnetization of the magnet at the rotor magnetic pole end without degrading the performance, and as a second object, to the outer magnet. An object of the present invention is to provide a multi-gap rotating electric machine that can improve the demagnetization resistance of an inner magnet.

(Invention according to Claim 1)
The present invention includes an annular rotor arranged concentrically with a rotating shaft and rotating integrally with the rotating shaft, an inner stator arranged with a gap on the inner diameter side of the rotor, and a gap on the outer diameter side of the rotor. A rotor iron core formed of a soft magnetic material, an inner magnet embedded in an inner peripheral side of the rotor iron core to form an inner rotor magnetic pole, and the rotor iron core And an outer magnet that forms an outer rotor magnetic pole, and the rotor core has a rotor inner salient pole and a rotor outer salient pole between the inner rotor magnetic poles adjacent to each other in the circumferential direction and the outer rotor magnetic pole, respectively. In the multi-gap rotating electric machine to be formed, both end portions in the circumferential direction of the inner rotor magnetic pole and the outer rotor magnetic pole are called magnetic pole ends, and the radial thicknesses of the inner magnet and the outer magnet are respectively set. When the outer peripheral surface of the inner magnet and the inner peripheral surface of the outer magnet are referred to as the anti-stator side surfaces, the inner magnet and / or the outer magnet are magnets at the magnetic pole ends. The anti-stator side surface is inclined so that the thickness gradually decreases from the central side in the circumferential direction toward the circumferential end.

  In the multi-gap rotating electric machine of the present invention, the magnet thickness at the magnetic pole end portion is increased from the central side in the circumferential direction by inclining the anti-stator side surface of the magnet in either or either of the inner magnet and the outer magnet. It gradually becomes smaller toward the direction end. That is, the radial width of the rotor yoke that forms a shared magnetic path between the inner rotor magnetic pole and the outer rotor magnetic pole is gradually increased from the center side in the circumferential direction of the inner rotor magnetic pole and the outer rotor magnetic pole toward the circumferential end (widely). It has become. Thereby, magnetic saturation can be suppressed in the rotor yoke in the vicinity of the magnetic pole end, so that magnetic leakage to the magnet can be prevented, and as a result, local demagnetization of the magnet at the magnetic pole end can be prevented.

FIG. 3 is a ¼ cross-sectional view in the circumferential direction illustrating the magnetic circuit of the motor according to the first embodiment. 1 is a partial cross-sectional view of a rotor according to Embodiment 1. FIG. 1 is a longitudinal sectional view showing a configuration of a motor according to Embodiment 1. FIG. It is the connection diagram which connected the inner and outer stator windings to the inverter. 6 is a partial cross-sectional view of a rotor according to Embodiment 2. FIG. 6 is a partial cross-sectional view of a rotor according to Embodiment 3. FIG. FIG. 6 is a longitudinal sectional view illustrating a configuration of a motor according to a fourth embodiment. It is sectional drawing which shows a part of motor magnetic circuit which concerns on a prior art. It is a partial cross section figure of the rotor which shows the flow of the q-axis magnetic flux which concerns on a prior art. It is a partial cross section figure of the rotor which shows the flow of the d-axis magnetic flux which concerns on a prior art.

  The mode for carrying out the present invention will be described in detail with reference to the following examples.

Example 1
In the first embodiment, an example in which the multi-gap rotating electric machine of the present invention is applied to a traveling motor (hereinafter referred to as a motor 1) of a hybrid vehicle will be described.
As shown in FIG. 3, the motor 1 includes an annular rotor 4 that is supported by the shaft 3 via the rotor holding member 2, an inner stator 5 that is disposed with a gap on the inner diameter side of the rotor 4, And an outer stator 6 disposed with a gap on the outer diameter side of the rotor 4.
The shaft 3 is a rotating shaft of the present invention, and both end portions thereof are rotatably supported by the motor housing 8 via bearings 7 respectively.

The rotor holding member 2 includes, for example, a cylindrical boss portion 2a formed of a nonmagnetic SUS material, and a disk portion 2b extending from one end portion of the cylindrical boss portion 2a in the outer diameter direction. The boss part fits on the outer periphery of the shaft 3 and rotates together with the shaft 3.
As shown in FIG. 1, the rotor 4 includes a rotor core 4a, an inner magnet 9 that is embedded on the inner peripheral side of the rotor core 4a to form an inner rotor magnetic pole, and an outer side that is embedded on the outer peripheral side of the rotor core 4a. It is comprised with the outer magnet 10 which forms a rotor magnetic pole. FIG. 1 is a cross-sectional view showing a magnetic circuit of the motor 1, but hatching for displaying the cross section is omitted.

For example, the rotor core 4a is formed by laminating a plurality of core sheets obtained by punching electromagnetic steel plates into a ring shape with a press, and by a fastening member (not shown) such as a rivet or a through bolt inserted in the laminating direction. It is connected and fixed to the disk portion 2b (see FIG. 3).
As shown in FIG. 2A, the rotor iron core 4a has a rotor inner salient pole 4b formed between the inner rotor magnetic poles (inner magnets 9) adjacent in the circumferential direction, and the outer rotor adjacent in the circumferential direction. A rotor outer salient pole 4c is formed between the magnetic poles (outer magnets 10).
The rotor inner salient pole 4b and the rotor outer salient pole 4c are formed at the same position in the circumferential direction of the rotor iron core 4a. Further, between the inner rotor magnetic pole (inner magnet 9) and the outer rotor magnetic pole (outer magnet 10), a rotor yoke 4d in which the inner magnetic flux and the outer magnetic flux are joined and formed in an annular shape is formed. The inner magnetic flux is a magnetic flux that flows through the rotor iron core 4 a through the rotor inner salient pole 4 b with the inner stator 5, and the outer magnetic flux is the rotor iron core 4 a through the rotor outer salient pole 4 c with the outer stator 6. The magnetic flux flowing through

An inner magnet insertion hole 11 for inserting the inner magnet 9 is formed on the inner peripheral side of the rotor core 4a, and an outer magnet insertion hole 12 for inserting the outer magnet 10 is formed on the outer peripheral side of the rotor core 4a. It is formed. However, the outer magnet insertion hole 12 is formed in a hole shape in which the outer peripheral side of the rotor core 4a is closed, whereas the inner magnet insertion hole 11 is formed in a concave groove shape in which the inner peripheral side of the rotor core 4a is opened. . That is, the outer magnet 10 is a magnet-embedded type that is inserted into the outer magnet insertion hole 12 in a state in which the periphery is surrounded, whereas the inner magnet 9 is an inner magnet with a radially inner peripheral surface exposed. A so-called inset type structure that is inserted into the insertion hole 11 is employed. In the present invention, it is defined as a “magnet buried type” including an inset type.
As shown by arrows in FIG. 1, the inner magnet 9 and the outer magnet 10 have the same magnetic poles facing each other in the radial direction of the rotor 4, and the directions of the magnetic fields of the inner rotor magnetic pole and the outer rotor magnetic pole are It is magnetized so as to be alternately different in the circumferential direction.

As shown in FIG. 1, the inner stator 5 includes an inner stator core 5b in which a plurality of inner slots 5a are formed at equal intervals in the circumferential direction, and three (for example, full-pitch winding) wound around the inner stator core 5b. It is comprised with the inner side stator winding 5c of a phase (U, V, W).
As shown in FIG. 1, the outer stator 6 includes an outer stator core 6b in which a plurality of outer slots 6a are formed at equal intervals in the circumferential direction, and three (for example, full-pitch winding) wound around the outer stator core 6b. The outer stator winding 6c of the phase (X, Y, Z).
Further, the inner stator 5 and the outer stator 6 have the same number of slots.

For example, as shown in FIG. 4, the inner stator winding 5 c and the outer stator winding 6 c are connected to each other in series and connected in a star shape, and each phase end portion on the anti-neutral point side. Is connected to the inverter 13. The inverter 13 is controlled by an ECU (not shown), which is an electronic control device, based on detection information of a rotor position detection sensor (not shown) that detects the rotational position of the rotor 4, and converts the power of the DC power source B to AC. It is converted into electric power and supplied to the inner stator winding 5c and the outer stator winding 6c.
When the inner stator winding 5c and the outer stator winding 6c are excited through the inverter 13, the inner stator 5 and the outer stator 6 are opposed to each other in the radial direction across the rotor 4 at the same circumferential position. A winding magnetomotive force is generated so that the magnetic poles have the same polarity.

Next, an inner magnet 9 and an outer magnet 10 having the features of the present invention according to claim 1 will be described with reference to FIG. FIG. 2 is a partial cross-sectional view of the rotor 4 including the inner rotor magnetic pole and the outer rotor magnetic pole, but hatching for displaying the cross section is omitted.
First, each part of the inner magnet 9 and the outer magnet 10 is defined as follows.
a) The central portion of the inner rotor magnetic pole and the outer rotor magnetic pole in the circumferential direction is referred to as the magnetic pole center, the thickness of the inner magnet 9 at the magnetic pole center is denoted as P1, and the thickness of the outer magnet 10 is denoted as P3.
b) The circumferential end portions of the inner and outer rotor magnetic poles are called magnetic pole ends, the thickness of the inner magnet 9 at the magnetic pole ends is expressed as P2, and the thickness of the outer magnet 10 is expressed as P4. To do.
c) The outer peripheral surface of the inner magnet 9 and the inner peripheral surface of the outer magnet 10, that is, the rotor yoke surface, are referred to as anti-stator side surfaces, respectively.
The inner magnet 9 and the outer magnet 10 of Example 1 have a relationship of P1> P2 and P3> P4, respectively, and as shown in FIG. 2A, P2 and P4 are circumferential ends from the magnetic pole center side. The surface on the side opposite to the stator is inclined so as to gradually become smaller.

(Operation and Effect of Example 1)
Since the motor 1 according to the first embodiment employs the magnet-embedded rotor 4 in which the inner magnet 9 is embedded on the inner peripheral side of the rotor core 4a and the outer magnet 10 is embedded on the outer peripheral side, magnet torque and reluctance torque are employed. Both can be utilized.
In addition, the rotor 4 tilts the anti-stator side surfaces of the inner magnet 9 and the outer magnet 10 at the magnetic pole ends of the inner rotor magnetic pole and the outer rotor magnetic pole, so that the magnet thicknesses P2 and P4 are circumferential from the magnetic pole center side. It gradually becomes smaller toward the edge. In other words, the radial width of the rotor yoke 4d that forms a shared magnetic path between the inner rotor magnetic pole and the outer rotor magnetic pole gradually increases (widens) toward the circumferential ends of the inner rotor magnetic pole and the outer rotor magnetic pole. Yes. As a result, as shown by a thick arrow in FIG. 2B, magnetic saturation is caused in the rotor yoke 4d near the magnetic pole end where the q-axis magnetic flux generating the reluctance torque and the d-axis magnetic flux generating the magnet torque are most concentrated. Can be suppressed. As a result, since magnetic leakage to the inner magnet 9 and the outer magnet 10 can be prevented, local demagnetization of the inner magnet 9 and the outer magnet 10 at the magnetic pole end can be prevented without deteriorating the motor performance.

Examples 2 to 4 according to the present invention will be described below.
Reference numerals common to the first embodiment have the same components or functions as those of the first embodiment, and the first embodiment is referred to for the description.
(Example 2)
In the second embodiment, as shown in FIG. 5A, chamfers are formed at corners of the outer rotor magnetic poles where the stator side surface of the outer magnet 10 and the circumferential end surface intersect. The stator side surface of the outer magnet 10 is a surface opposite to the anti-stator side surface described in the first embodiment, that is, the outer peripheral surface of the outer magnet 10.

Further, a space S is provided between the outer magnet insertion hole 12 formed in the rotor core 4a and a corner portion of the chamfered outer magnet 10.
In the configuration of the second embodiment, since the space S provided in the outer magnet insertion hole 12 acts as a magnetic gap, as shown in FIG. 5B, the demagnetizing field strength applied to the outer magnet 10 (broken line in the figure). (Magnetic flux indicated by an arrow) can be reduced. As a result, the demagnetization of the outer magnet 10 at the magnetic pole end can be further suppressed. Instead of providing the space S in the outer magnet insertion hole 12 corresponding to the corners of the chamfered outer magnet 10, a nonmagnetic substance such as aluminum or resin can be provided in the space S.

(Example 3)
In the third embodiment, as shown in FIG. 6A, a bridge 13 is provided that connects the inner peripheral side and the outer peripheral side of the outer magnet insertion hole 12 and divides the outer magnet insertion hole 12 in the circumferential direction. This is an example. In this case, the outer magnet 10 forming the outer rotor magnetic pole is inserted in two outer magnet insertion holes 12 divided by the bridge 13. In other words, the outer rotor magnetic pole is formed by a set of two outer magnets 10 inserted into two outer magnet insertion holes 12 divided by the bridge 13.
In the configuration of the third embodiment, the demagnetization in the inner magnet 9 can be reduced because the outer magnetic flux opposes the demagnetizing field applied to the inner magnet 9 through the bridge 13 as shown in FIG. 6B.

  In addition, by providing the bridge 13 that divides the outer magnet insertion hole 12 in the rotor iron core 4a, the centrifugal strength of the rotor 4 can be increased. That is, when the centrifugal force acts on the outer magnet 10 by the rotation of the rotor 4, the thin portion (the outer peripheral side of the outer magnet insertion hole 12) of the rotor core 4 a covering the outer peripheral surface (stator side surface) of the outer magnet 10. It is possible to prevent the outer magnet 10 from being pressed and bulging outward in the radial direction. Thereby, it can avoid that the outer periphery of the rotor 4 contacts the inner periphery of the outer side stator 6, and the magnetic gap between the rotor 4 and the outer side stator 6 can be maintained uniformly.

Example 4
The fourth embodiment is an example of the three-surface gap type motor 1.
As shown in FIG. 7, the three-sided gap type motor 1 includes side stators 14 that face each other with a gap on the end face of the rotor 4 on the side opposite to the disk portion (left side in the figure). The side stator core 14 is connected to the inner stator core 5b and the outer stator core 6b. The side stator core 14a is wound around the side stator core 14a (for example, full-pitch winding), and the inner stator winding 5c and the outer stator are wound. A side stator winding 14b that connects the winding 6c in series is provided.
Since this three-surface gap type motor 1 forms a magnetic gap on three surfaces between the rotor 4 and the stators 5, 6, and 14, further torque can be obtained by applying the example described in any one of the first to third embodiments. Up is possible.

(Modification)
In the first embodiment, the configuration described in claim 1 is applied to both the inner rotor magnetic pole and the outer rotor magnetic pole. That is, the anti-stator side surface of the magnetic pole end is inclined to both the inner magnet 9 and the outer magnet 10, but only one of the inner magnet 9 and the outer magnet 10 is inclined to the anti-stator side surface of the magnetic pole end. May be.
In the second embodiment, an example in which chamfering is provided at the corner portion of the outer magnet 10 is described. However, not only the outer magnet 10 but also chamfering can be provided at the corner portion of the inner magnet 9. In this case, providing a space in the inner magnet insertion hole 11 corresponding to the corner portion of the chamfered inner magnet 9 or disposing a nonmagnetic material such as aluminum or resin is the same as in the case of the outer rotor magnetic pole. .
In the third embodiment, an example in which the outer magnet insertion hole 12 is divided into two by the bridge 13 is described. However, the outer magnet insertion hole 12 can also be divided by two or more bridges 13.

1 Motor (Multi-gap type rotating electrical machine)
3 Shaft (Rotating shaft)
4 rotor 4a rotor core 4b rotor inner salient pole 4c rotor outer salient pole 5 inner stator 6 outer stator 9 inner magnet (inner rotor magnetic pole)
10 Outer magnet (outer rotor magnetic pole)
13 Bridge

Claims (4)

An annular rotor (4) disposed concentrically with the rotating shaft (3) and rotating integrally with the rotating shaft (3);
An inner stator (5) disposed with a gap on the inner diameter side of the rotor (4);
An outer stator (6) disposed with a gap on the outer diameter side of the rotor (4),
The rotor (4) includes a rotor core (4a) formed of a soft magnetic material, an inner magnet (9) embedded in an inner peripheral side of the rotor core (4a) to form an inner rotor magnetic pole, and the rotor An outer magnet (10) embedded in the outer peripheral side of the iron core (4a) to form an outer rotor magnetic pole, and the rotor iron core (4a) is disposed between the inner rotor magnetic poles adjacent in the circumferential direction and the outer rotor magnetic pole. A multi-gap rotating electrical machine (1) that forms a rotor inner salient pole (4b) and a rotor outer salient pole (4c), respectively,
Both ends of the inner rotor magnetic pole and the outer rotor magnetic pole in the circumferential direction are called magnetic pole ends,
The radial thicknesses of the inner magnet (9) and the outer magnet (10) are called magnet thicknesses, respectively.
When the outer peripheral surface of the inner magnet (9) and the inner peripheral surface of the outer magnet (10) are called anti-stator side surfaces, respectively.
The inner magnet (9) and / or the outer magnet (10) may be configured so that the magnet thickness at the magnetic pole end portion gradually decreases from the circumferential center to the circumferential end. A multi-gap rotating electric machine characterized in that a stator side surface is inclined. In the multi-gap type rotating electrical machine (1) according to claim 1,
When the surface on the inner peripheral side of the inner magnet (9) and the surface on the outer peripheral side of the outer magnet (10) are respectively referred to as a stator side surface,
Both or one of the inner magnet (9) and the outer magnet (10) is chamfered at a corner where the stator side surface and the circumferential end surface intersect at the magnetic pole end,
The rotor iron core (4a) is a multi-gap type rotating electrical machine having nonmagnetic portions at corners of the chamfered inner magnet (9) and outer magnet (10). In the multi-gap type rotating electrical machine (1) according to claim 2,
The non-magnetic portion is a space (S), and is a multi-gap rotating electric machine. In the multi-gap type rotating electrical machine (1) according to any one of claims 1 to 3,
The rotor core (4a) has a magnet insertion hole (12) on the radially outer peripheral side, and connects the inner peripheral side and outer peripheral side of the magnet insertion hole (12) to form the magnet insertion hole (12). At least one bridge (13) that divides
The multi-gap rotating electrical machine, wherein the outer rotor magnetic pole is formed by the outer magnet (10) inserted into the magnet insertion hole (12) divided by the bridge (13).

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