JPH08251848A - Rotor of permanent magnet type synchronous rotary machine - Google Patents

Abstract

PURPOSE: To realize a rotor suitable for a permanent magnet type synchronous rotary machine which maintains in a wider range a constant output characteristic in a high speed range for use in an object such as electric vehicle, assures improvement of starting characteristic and prevents disturbance thereof. CONSTITUTION: In a rotor of a permanent magnet type synchronous rotary machine where a rotor core 1, permanent magnet inserting holes 2 provided in the equal pitch in the axial direction in the external circumference side of the rotor core 1 and a drain hole 3 for preventing leakage magnetic flux provided between the permanent magnet inserting holes 2, 2 are provided and the permanent magnets in different adjacent poles are inserted into the permanent magnet inserting holes 2, a rotor of the permanent magnet type synchronous rotary machine is constituted by providing a means for changing distribution of magnetic flux in the axial direction. Moreover, a secondary conductor is buried in the drain hole 3 and both ends of such conductor are connected with a short-circuit ring.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotor of a permanent magnet type synchronous rotating electric machine having a constant torque characteristic in a low speed region and a constant output characteristic in a high speed region by performing vector control, and particularly to an electric vehicle and a main shaft. The present invention relates to a rotor suitable for a permanent magnet type synchronous rotating electric machine capable of maintaining a constant output characteristic in a wide range in a high speed region such as driving.

[0101]

2. Description of the Related Art As a first prior art, which is a structural reference, a permanent magnet is mounted on the permanent magnet as a rotor of a permanent magnet generator, the permanent magnet being mounted circumferentially on the outer periphery of a rotating shaft. And a plurality of magnetic plates forming the magnetic poles, and a plurality of non-magnetic members fixed to the outer periphery of the rotary shaft to form a cylindrical body by being alternately joined to the magnetic plates in the circumferential direction. (For example, Japanese Patent Laid-Open No. 4-138042). As a second conventional technique, there is a self-starting permanent magnet synchronous motor having a structure in which a permanent magnet is embedded inside a rotor core having a squirrel cage secondary conductor similar to that of an induction motor (for example, Japanese Patent Publication No. 63-20105). As a third conventional technique, which serves as a reference in terms of performance, a second part of a non-magnetic flat member similar to the first part, which is a first part including a ferromagnetic pole shoe and a salient pole, is provided. A part, a step part is provided on the gap side of the pole shoe, and a third part in which a semi-cylindrical permanent magnet is affixed to this step part, and a fourth part consisting of an excitation winding for direct current excitation are axially arranged. The second part is firmly fixed to the left and right of the first part, the third part is firmly fixed to the outside of the first part, and the fourth part is wound around the side surface of the first part to secure the field of the permanent magnet type synchronous motor. Some are configured (for example, Japanese Patent Laid-Open No. 5-2367).
14 publication).

[0092]

However, when the current phase control is applied to the first prior art, the fixed field magnetic flux becomes large because the permanent magnet having the same length as the motor axial length is inserted. As a result, the induced voltage constant due to the permanent magnet field becomes large, and in a controller of normal capacity, the controller terminal voltage exceeds the allowable value at a considerably low rotation speed, and the ratio of the base rotation speed to the maximum rotation speed becomes narrow, There are performance drawbacks. Furthermore, the saturation of the magnetic circuit in the core makes it difficult to increase the reluctance torque,
The output in the base rotation speed region cannot be increased. The second conventional technique is effective in improving the starting characteristics and preventing the disturbance, but is difficult to manufacture. Further, in the third conventional technique, although the performance is good, since it is a hybrid type synchronous motor, the field poles are salient poles, and wind loss and noise occur in the high speed range. Since it is necessary to supply the power via the slip ring, there is a problem that the structure is complicated and it is difficult to manufacture. Therefore, the present invention is to realize a rotor of a synchronous rotating electric machine that can maintain constant output characteristics in a wide range in a high speed region, has little wind loss and noise, is easy to manufacture, and is effective in improving starting characteristics and preventing disturbance. To aim.

[0093]

In order to solve the above problems, a rotor core 1 is formed by laminating disk-shaped thin plates made of a magnetic material in the axial direction, and the rotor core 1 is provided with an equal pole pitch in the outer peripheral side and the axial direction. A permanent magnet insertion hole 2, a leakage magnetic flux preventing hole 3 provided between the permanent magnet insertion holes 2 and 2, and a permanent magnet having different polarities alternately inserted into the permanent magnet insertion hole 2 In the rotor of the permanent magnet type synchronous rotating electric machine, the rotor of the permanent magnet type synchronous rotating electric machine is provided with means for changing the magnetic flux distribution in the axial direction formed by the permanent magnet. There are the following two means for changing the magnetic flux distribution in the axial direction created by the permanent magnet. As means corresponding to claim 2, the permanent magnet is divided into a plurality of pieces in the axial direction, and the sum of the lengths of the divided permanent magnets 4a, 4a is made shorter than the length of the permanent magnet insertion hole 2 in the axial direction. This is because a magnetic space 21 is generated when the divided permanent magnets 4a and 4a are inserted into the magnet insertion hole 2. As a means corresponding to claim 3, the permanent magnet is divided into a plurality of pieces in the axial direction, and the divided permanent magnets 4a and 4b have different energy products. As an embodiment corresponding to claim 4, the hole 3 is deepened toward the axial center, and the permanent magnet insertion hole 2 is formed on a straight line connecting the bottom of the hole 3a and the middle of the adjacent hole 3a. The rotor is provided with an inclination so that its end portion is lowered toward the rotation direction side. As an embodiment corresponding to claim 5, a secondary conductor 5 is embedded in the hole 2 and both ends thereof are connected by a short-circuit ring 6. As an embodiment corresponding to claim 6, slots 8 are provided on an outer circumferential side of the rotor core 1 between the leakage magnetic flux preventing holes 3 and 3 on an equal circumferential pitch to form a secondary conductor of an induction motor. Similarly, the secondary conductor 5 is embedded by die casting or the like, and both ends thereof are connected by the short-circuit ring 6.

[004]

By the above means, the magnetic flux density in the magnetic space portion or the portion with the permanent magnet having a low energy product is lowered,
The induced voltage constant is reduced, and constant output characteristics can be maintained in a higher speed range. Furthermore, since the magnetic field in that part becomes smaller,
Increases reluctance torque. Further, a damper effect is produced by embedding the secondary conductor and connecting both ends thereof with a short-circuit ring.

[0095]

Embodiments of the present invention will be described below with reference to FIGS. 1 (a) and 1 (b). In the rotor core 1 in which disc-shaped magnetic thin plates are laminated, the rectangular permanent magnet insertion hole 2 is axially penetrated so as to be orthogonal to the magnetic pole center axis A divided into the same number as the motor poles at an equal pole pitch. Is provided. Between the permanent magnet insertion holes 2, a fan-shaped hole 3 for preventing leakage magnetic flux is opened to the outside. From the left and right of the permanent magnet insertion hole 2,
The cross-sectional shape is similar to the permanent magnet insertion hole 2, and the sum (2La) of the lengths La is shorter than the length of the permanent magnet insertion hole 2, the permanent magnets 4a and 4a are alternately replaced with the polarities of adjacent ones, and the end face is the rotor core 1 Align it with the end face of and insert and fix.
As a result, a magnetic space portion 21 having a length Lb is formed in the central portion of the permanent magnet insertion hole 2, and the magnetic flux densities of the teeth portion and the yoke portion of the armature core (not shown) facing this are formed. Becomes almost 0 when there is no load. In addition,
A non-magnetic material may be embedded in the magnetic space portion 21 or resin may be molded to firmly fix the permanent magnets 4a and 4a. For the sake of explanation, the permanent magnet is divided into two in the embodiment, but may be divided into a plurality of pieces such that the sum of the lengths is shorter than the length of the permanent magnet insertion hole 2. As shown in FIG. 1C, the axial magnetic flux distribution created by the permanent magnets is a magnetic flux φd in the d-axis direction in the range La from both ends of the rotor core 1 and a leakage flux φl in the range Lb in the central portion.

FIG. 2A shows the second embodiment of the present invention. The permanent magnets 4a, 4a of the embodiment are buried from the end face of the rotor core 1 toward the central portion, and the magnetic space portions 21 each have a length of Lb / 3. In this case, when a non-magnetic material is embedded in the magnetic space portion 21 or a resin is molded, both ends may be used for adjusting the imbalance weight. The axial magnetic flux distribution created by the permanent magnets is, as shown in FIG. 2B, a leakage magnetic flux φl in the range of Lb / 3 from both ends of the rotor core 1, a magnetic flux φd in the d-axis direction in the range of La inside thereof, Lb / 3 at the center
In the range of, the leakage magnetic flux is φl. 3A and 3B show a third embodiment of the present invention. A permanent magnet having a low energy product is inserted at a position corresponding to the space portion 21 of the embodiment and the second embodiment, and magnetic flux densities of a tooth portion and a yoke portion of an armature core (not shown) facing this portion. Is lower than other parts. The rotor core 1 is divided into three parts, and in the embodiment, the 1a portion having a length La is
Insert the permanent magnet insertion hole 2a, which has a low hole height, into the length Lb of 1
Two types of permanent magnet insertion holes 2b having a high hole height are provided in the b portion. Permanent magnets 4a and 4a having a high energy product (for example, rare earth magnets) are inserted in the permanent magnet insertion hole 2a, and permanent magnets 4b having a low energy product (for example, a ferrite system) are inserted in the permanent magnet insertion hole 2b. insert. The amount of expensive permanent magnets (rare earth magnets) having a high energy product is reduced. As shown in FIG. 3C, the axial magnetic flux distribution created by the permanent magnets is as shown in FIG.
Of the permanent magnet 4 having a high energy product in the range of La from both ends of
The magnetic flux φdh produced by a is in the d-axis direction, and the magnetic flux φdl produced by the permanent magnet 4b has a low energy product in the range of Lb in the central portion. FIG. 4A shows a fourth embodiment of the present invention. The arrangement of the permanent magnet 4a having a high energy product and the permanent magnet 4b having a low energy product in the third embodiment is reversed. In the rotor core 1, the length of the 1a portion in the first embodiment is Lb / 2, the permanent magnet insertion hole 2c having a high hole height is the 2b portion of the 1b portion having the Lb length, and 2 types of permanent magnet insertion holes 2d having a low height are provided. In this case, the permanent magnets 4a and 4a having a high energy product in the third embodiment are replaced with a single permanent magnet 4d having a length of 2La, and the permanent magnet 4b having a low energy product is a permanent magnet having a length of Lb / 2. As shown in FIG. 4B, the axial magnetic flux distribution produced by the permanent magnets 4c and 4c is d produced by the permanent magnet 4c having a low energy product in the range of Lb / 2 from both ends of the rotor core 1 as shown in FIG. Axial magnetic flux φd
In the range of 1 and 2 Lb at the central portion, the energy product is the magnetic flux φdh in the d-axis direction created by the other-field permanent magnet 4d. In the third and fourth embodiments, the permanent magnet 4a having a high energy product
Is a Nd-Fe-B rare earth magnet having a maximum energy product of 30 MGoe, and a permanent magnet 4b having a low energy product is a ferrite magnet of 4 MGOe. The ratio B / A of B is about 3, and the length ratio La / Lb is 1. In this case, when no load is applied, the teeth of the armature core (not shown) facing the permanent magnet insertion hole 2b and the magnetic flux density of the yoke are different from those of the teeth of the armature core facing the permanent magnet insertion hole 2a. , About 1/3 of the magnetic flux density of the yoke part.

FIG. 5 is a front view showing the fifth embodiment.
In this example, the hole 3 of the embodiment is a long hole 3a that is deepened toward the axis. Furthermore, on a straight line B connecting a point 3c at the bottom of the elongated hole 3a and a point 3d in the middle of the adjacent elongated hole 3a,
The magnet insertion hole 2 is provided so as to be inclined in the same direction with respect to the direction orthogonal to the magnetic pole central axis A so that the end portion on the rotation direction side of the rotor is lowered. In this case, the reluctance becomes directional, and if the rotation direction is fixed, starting and gear shifting will be easier.

FIG. 6 shows a sixth embodiment of the present invention. Figure 6
As shown in (a), the bar-shaped secondary conductor 5 of the same shape is provided in the hole 3 in the embodiment, and the ring-shaped short-circuit ring 6 in which the permanent magnet insertion hole 2a is cut out is provided at both ends thereof. ,
As shown in FIG. 6B, the secondary conductor 5 and the short circuit ring 6 are integrally formed by die casting. From the cutout portion of the short-circuit ring 6,
After inserting the permanent magnets 4a, 4a or 4c, 4c into the permanent magnet insertion hole 2a, the permanent magnets 4a, 4a or 4c, 4
Fix c with adhesive or the like. FIG. 7 shows a seventh embodiment of the present invention. The bar-shaped 2 having the same shape is formed in the hole 3 in the embodiment.
The secondary conductor 5 is provided, and at both ends thereof, a polygonal short-circuit ring 7 is formed which connects the secondary conductor 5 with a through hole for tightly fitting the secondary conductor 5, and the polygonal short-circuit ring 7 is provided. Alternatively, after inserting 4c and 4c into the permanent magnet insertion hole 2a, the secondary conductor 5
And the short-circuit ring 7 are welded by plasma, TIG, MIG, or the like.
With this configuration, the permanent magnet can be prevented from deviating. FIG. 8 shows an eighth embodiment of the present invention. Slots 8 are formed on the same pitch circle between the holes 3 in the embodiment.
Is provided, the secondary conductor 5 is provided in the slot 8, short-circuit rings 6 are provided at both ends thereof, and the secondary conductor 5 and the short-circuit ring 6 are integrally formed by die casting. In this case, the inner diameter of the short-circuit ring 6 may be larger than the corner of the permanent magnet 4a, and the permanent magnet 4a may be inserted later.

The operation of the present invention will be described with reference to FIG. 9A is a graph showing the torque T and the current phase difference angle γ, and FIG. 9B is a graph showing the torque T and the rotation speed N. Tm is a magnet torque, Tr is a reluctance torque, and T is an output torque. The suffix 1 is the case of the first prior art and 2 is the case of the first to fifth embodiments of the present invention. . When a motor of the same size is designed, the reason why Tm2 is smaller than Tm1 is that the embodiment of the present invention reduces the amount of permanent magnets applied and the magnetic field magnetic flux. As a result, the no-load open circuit voltage of the motor is lowered. However, since the magnetic space portion 21 is provided and the permanent magnet 4b having a low energy product is partially inserted, the teeth of the armature core facing this portion and the no-load magnetic flux density of the yoke portion are small. Reluctance decreases, q
Since the magnetic flux in the axial direction is easier to flow, Tr2 compared to Tr1
Is getting bigger. Although the optimum current phase difference angles are different, the maximum values of the total sums T1 and T2 are almost equal. However, as can be seen from FIG. 9B, the present invention has an effect that the constant output range can be expanded to a higher speed rotation region because the induced voltage constant is small. In addition, the low motor no-load open-circuit voltage at the maximum rotation speed reduces the regeneration to the inverter and reduces the capacity of the controller.

[0101]

The above-mentioned structure has the following effects. (1) A magnetic space is provided in the axial direction of the permanent magnet insertion hole, or a permanent magnet having a low energy product is inserted to change the magnetic flux distribution in the axial direction. It becomes easier for the magnetic flux to flow, and the constant output range can be expanded to the high-speed rotation region. (2) Especially, in the case of the second embodiment, the amount of expensive permanent magnets having a high energy product can be reduced. (3) In the case of the sixth to eighth embodiments, since the damper effect is produced by the secondary conductor and the short-circuit ring, it is possible to improve the starting characteristics and prevent disorder.

[Brief description of drawings]

FIG. 1A is a front view showing a first embodiment of the present invention,
(B) Side sectional view, (c) Graph showing magnetic flux distribution in the axial direction.

FIG. 2A is a side sectional view showing the second embodiment of the present invention, and FIG. 2B is a graph showing the magnetic flux distribution in the axial direction.

FIG. 3 is a front view (including a partial cross-sectional view), a side cross-sectional view (b), and a graph showing magnetic flux distribution in the axial direction (c), showing a third embodiment of the present invention.

FIG. 4A is a side sectional view showing the fourth embodiment of the present invention, and FIG. 4B is a graph showing the magnetic flux distribution in the axial direction.

FIG. 5 is a front view showing a fifth embodiment of the present invention.

FIG. 6A is a front view showing a sixth embodiment of the present invention;
(B) Side sectional view.

FIG. 7 is a front view showing a seventh embodiment of the present invention.

FIG. 8 is a perspective view, partly in section, showing an eighth embodiment of the present invention.

FIG. 9 is a graph showing a torque curve of the present invention. (A) Relationship between torque and current phase angle, (b) Relationship between torque and rotation speed

[Explanation of symbols]

 1 rotor core 2, 2a, 2b, 2c, 2d permanent magnet insertion hole 3 through hole 3a elongated hole 3c bottom point 3d midway point 4a, 4b, 4c, 4d permanent magnet 21 magnetic space 5 secondary conductor 5, 6, 7 short-circuit rings, 8 slots

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Koichi Hirano No. 2 Kurosaki Shiroishi, Yawatanishi-ku, Kitakyushu, Fukuoka Prefecture Yasukawa Electric Co., Ltd. (72) Inventor Toshihiro Sawa No. 2 Kurosaki Shiroishi, Yawatanishi-ku, Kitakyushu, Fukuoka Yasukawa Electric Co., Ltd.

Claims (6)

[Claims] 1. A rotor core in which disk-shaped thin plates made of a magnetic material are axially laminated, permanent magnet insertion holes provided on the outer peripheral side of the rotor core at equal pole pitches in the axial direction, and between the permanent magnet insertion holes. In the rotor of the permanent magnet type synchronous rotating electric machine, which comprises a permanent magnet magnetized in a radial direction so that the leakage magnetic flux prevention holes provided in and the polarities of adjacent members inserted in the permanent magnet insertion hole are alternately different, A rotor for a permanent magnet type synchronous rotating electric machine, comprising means for changing a magnetic flux distribution in the axial direction formed by the permanent magnet. 2. The means for changing the magnetic flux distribution in the axial direction formed by the permanent magnet divides the permanent magnet into a plurality of pieces in the axial direction, and sums the respective lengths of the divided permanent magnets in the permanent magnet insertion hole. The rotor of a permanent magnet type synchronous rotating electric machine according to claim 1, wherein the rotor is shorter than the axial length. 3. The means for changing the magnetic flux distribution in the axial direction formed by the permanent magnet is one in which the permanent magnet is divided into a plurality of pieces in the axial direction, and the energy product of each of the divided permanent magnets is different. The rotor of the permanent magnet type synchronous rotating electric machine according to 1. 4. The hole is an elongated hole extending toward the center of the shaft,
4. The permanent magnet insertion hole is provided on a straight line that connects the bottom of the long hole and the middle of the adjacent long hole.
The rotor of a permanent magnet type synchronous rotating electric machine according to item. 5. A secondary conductor is embedded in the hole or the elongated hole, and both ends thereof are connected by a short-circuit ring.
The rotor of the permanent magnet type synchronous rotating electric machine according to any one of 1. 6. A slot is provided on the outer peripheral side of the rotor core between the holes or the oblong holes for preventing the leakage magnetic flux on a circle of equal pitch, a secondary conductor is embedded in the slot, and both ends thereof are connected by a short-circuit ring. Any one of claims 1 to 4
The rotor of a permanent magnet type synchronous rotating electric machine according to item.