JP4121673B2 - Permanent magnet synchronous motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a permanent magnet type synchronous motor used for electric compressors for refrigeration and air conditioning equipment and other general industries.
[0002]
[Prior art]
In recent years, electric compressors for refrigeration and air-conditioning equipment and other permanent magnet synchronous motors used in general industries have a surface arrangement type in which permanent magnets are arranged on the outer periphery of the rotor core, and the interior of the rotor core. The invention is broadly classified into an embedded type in which a permanent magnet is embedded. The present invention relates to an embedded type permanent magnet type synchronous motor.
[0003]
In an embedded permanent magnet type synchronous motor, the axial length of the permanent magnet may need to be shortened relative to the axial length of the rotor core depending on the motor characteristics and other conditions. At that time, in general, the center of the axial length of the rotor core and the center of the axial length of the permanent magnet are matched, and the axial direction of the rotor due to magnetic attraction between the stator and the rotor. It is necessary to suppress runout.
[0004]
Japanese Patent Laid-Open No. 9-182332 discloses a method for holding a permanent magnet when the axial length of the permanent magnet is shortened relative to the axial length of the rotor core.
[0005]
Hereinafter, the conventional method for holding a permanent magnet will be described with reference to the drawings.
[0006]
FIG. 10 is an axial cross-sectional view of a conventional embedded rotor. In FIG. 10, a permanent magnet 4 is embedded in a permanent magnet embedding hole 3 provided in the rotor core 2 of the rotor 1. The permanent magnet 4 is held by a holder 5, and the permanent magnet 4 is positioned in the rotor core 2 by closing the permanent magnet embedding hole 3 with two end plates 6.
[0007]
[Problems to be solved by the invention]
However, the conventional configuration requires a holder for positioning the permanent magnet, and there is a drawback that the cost of assembly and parts increases.
[0008]
SUMMARY OF THE INVENTION An object of the present invention is to solve the conventional problems and to provide an inexpensive permanent magnet type synchronous motor capable of positioning a permanent magnet only with a rotor core without using a holder.
[0009]
[Means for Solving the Problems]
In order to achieve this object, the present invention provides a rotor iron plate A having a plurality of permanent magnet embedding holes, which is laminated more than the axial length of the permanent magnet in order to embed the permanent magnet, and the permanent magnet One or more rotor iron plates B having magnetic flux short-circuit prevention holes arranged so as to communicate with the magnet embedding holes are laminated on one of the end surfaces in the axial direction of the laminated rotor iron plates A, and the rotation is further performed. A rotor iron core is formed by laminating one or a plurality of the rotor iron plates A on the axial end surface of the child iron plate B, and the rotor iron plate A and the rotor iron plate B in which the permanent magnets are embedded. By positioning the outer edge of the magnetic flux short-circuit prevention hole on the contact surface in contact with the axial end surface of the permanent magnet, it is possible to position the permanent magnet in the axial direction using only the rotor core without using a holder. So you can assemble and It is possible to reduce the cost of goods.
[0010]
Further, the present invention provides a rotor iron plate C having a shape in which a rotor iron plate A having a plurality of permanent magnet embedding holes is laminated and the permanent magnet embedding holes are not formed. One or more of the laminated rotor iron plates A are laminated on one of the axial end surfaces, and the contact surface of the rotor iron plate C with the rotor iron plate A is the axial end surface of the permanent magnet. By abutting, the permanent magnet can be positioned in the axial direction only with the rotor core without using a holder, and one end plate is disposed on the other axial end face of the magnet embedding hole. Only the two ends of the magnet embedding hole can be closed, so that the cost can be further reduced.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
According to a first aspect of the present invention, there is provided a stator in which a winding is wound around a stator core, and a plurality of permanent magnets that are rotatably rotated facing an inner cylindrical surface of the stator core. An electric motor having an embedded rotor, wherein the rotor iron plate A having a plurality of permanent magnet embedding holes is larger than the axial length of the permanent magnet in order to embed the permanent magnet. One or a plurality of laminated rotor iron plates B having magnetic flux short-circuit prevention holes arranged so as to communicate with the permanent magnet embedding holes are disposed on one of the axial end surfaces of the laminated rotor iron plates A. The rotor iron plate A and the rotor, which are formed by laminating one or more of the rotor iron plates A on the axial end surface of the rotor iron plate B and in which the permanent magnets are embedded. The magnetic flux short on the contact surface of the iron plate B The outer edge portion of the prevention hole abuts against the axial end surface of the permanent magnet, whereby the permanent magnet can be positioned in the axial direction only by the rotor core, and the cost of assembly and parts can be reduced. Has the effect of being able to
[0012]
According to the second aspect of the present invention, a stator in which a winding is wound around a stator core, and a plurality of permanent magnets are rotatably rotated so as to face the inner cylindrical surface of the stator core. An electric motor having an embedded rotor, wherein the rotor iron core is formed by laminating a rotor iron plate A having a plurality of permanent magnet embedding holes, and the permanent magnet embedding without the permanent magnet embedding holes. The rotor iron plate C having a shape for closing the holes for use is formed by laminating one or more rotor iron plates C on one of the axial end surfaces of the laminated rotor iron plates A, and the rotor of the rotor iron plate C Since the contact surface with the iron plate A contacts the axial end surface of the permanent magnet, the permanent magnet can be positioned in the axial direction only by the rotor core. Further, since one of the permanent magnet embedding holes is closed by the rotor iron plate C, an end plate is disposed on the other axial end surface of the permanent magnet embedding hole to close the permanent magnet embedding hole. Since both ends of the permanent magnet embedding hole can be closed only by using one end plate, the cost of assembly and parts can be further reduced.
[0013]
According to the invention described in claim 2, the axial end faces of the side where the permanent permanent magnets of the rotor iron plate C in the form of closing a permanent magnet embedding hole without chromatic magnet embedding holes do not abut, By laminating the rotor iron plate A having permanent magnet embedding holes, the magnetic resistance of the magnetic circuit between the NS surfaces at the axial end of the permanent magnet is increased, the leakage flux is reduced, and the characteristics of the motor are improved. It has the effect that it can be made.
[0014]
According to a third aspect of the present invention, in addition to the first or second aspect of the present invention, a starting squirrel-cage conductor is disposed on the rotor core, whereby a self-starting permanent magnet type is provided. In addition to constituting the synchronous motor, the permanent magnet can be positioned in the axial direction only by the rotor core, and thus the cost of assembling and parts can be reduced.
[0015]
According to the invention described in claim 4 , in addition to the invention described in any one of claims 1 to 3 , a strong magnetic force can be obtained because the permanent magnet is formed of a rare earth magnet. For this reason, the volume of the rotor and the entire electric motor can be reduced.
[0016]
【Example】
Embodiments of a permanent magnet type synchronous motor according to the present invention will be described below with reference to the drawings. In addition, about the same structure as the past, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted. Since the stator has the same configuration as a general permanent magnet type synchronous motor, description of the stator is also omitted.
[0017]
(Example 1)
This will be described with reference to FIGS. FIG. 1 is an axial sectional view of a rotor of a permanent magnet type synchronous motor according to a first embodiment of the present invention. In FIG. 1, 1 is a rotor and 2 is a rotor core. 2a is the rotor core which laminated | stacked the rotor iron plate A, The top view of the rotor iron plate A is shown in FIG. In FIG. 2, 3 is a permanent magnet embedding hole. By laminating the rotor iron plate A, as shown in FIG. 1, the permanent magnet embedding hole 3 is continuous in the axial direction, and the permanent magnet 4 is embedded. Further, 2b1 in FIG. 1 is a rotor core in which a rotor iron plate B is laminated on the axial end surface of the rotor core 2a, and FIG. 3, reference numeral 7 denotes a magnetic flux short-circuit prevention hole, which is disposed at the same position as the permanent magnet embedding hole 3 of the rotor iron plate A of FIG. 2, and the hole width Q is the width of the permanent magnet embedding hole 3. It is set narrower than P. By laminating the rotor iron plate B on the end face in the axial direction of the rotor core 2a, the magnetic flux short-circuit prevention hole 7 is connected in the axial direction so as to communicate with the permanent magnet embedding hole 3 as shown in FIG. In FIG. 1, 2c1 is a rotor core in which one or more rotor iron plates A are further laminated on the axial end surface of the rotor core 2b1. In FIG. 1, reference numeral 6 denotes an end plate made of a non-magnetic material, and fragments of the permanent magnet 4 generated when the permanent magnet 4 is embedded in the permanent magnet embedding hole 3 flow out of the rotor 1 or externally. In order to prevent the foreign matter from entering the magnet embedding hole 3, the permanent magnet embedding hole 3 and the magnetic flux short-circuit preventing hole 7 are closed.
[0018]
In FIG. 1, the axial end surface 9 of the permanent magnet 4 abuts on the outer edge portion 8 of the magnetic flux short-circuit prevention hole 7 on the abutting surface of the rotor core 2b1 with the rotor core 2a. The leakage magnetic flux 10a1 between the NS surfaces at the end of the direction passes from the rotor core 2a through the rotor core 2b1, further across the magnetic flux short-circuit prevention hole 7, and again through the rotor core 2b1 and the rotor core 2a. Return to the permanent magnet 4. The leakage magnetic flux 10b1 passes from the rotor core 2a through the rotor core 2b1, further through the rotor core 2c1, across the permanent magnet embedding hole 3, and again through the rotor core 2c1, the rotor core 2b1, and the rotor core 2a. Return to the permanent magnet 4. Here, by configuring the rotor core 2b1 with one or as few rotor iron plates B as possible to position the permanent magnets, the magnetic resistance of the magnetic circuit through which the leakage flux 10a1 passes increases, and the leakage flux 10a1 decreases. In addition, the width P of the permanent magnet embedding hole 3 of the rotor iron plate A constituting the rotor core 2c1 is wider than the width Q of the magnetic flux short-circuit prevention hole 7 of the rotor iron plate B. Compared with the case where the core 2c1 is composed of the rotor iron plate B, the magnetic resistance of the magnetic circuit of the leakage magnetic flux 10b1 is increased, and the leakage magnetic flux 10b1 can be reduced. Therefore, the characteristics of the electric motor can be improved. Further, since the permanent magnet 4 is attracted to the outer edge portion 8 of the magnetic flux short-circuit prevention hole 7 of the rotor core 2b1, it is possible to position the permanent magnet 4 in the axial direction using only the rotor core 2 without using a holder. And the cost of assembly and parts can be reduced.
[0019]
Here, the number of laminated rotor iron plates B is set so that the center of the axial length of the rotor core 2 and the center of the axial length of the permanent magnet 4 coincide with each other. Is set in the same way.
[0020]
(Example 2)
This will be described with reference to FIGS. FIG. 4 is an axial sectional view of a rotor of a permanent magnet type synchronous motor according to a second embodiment of the present invention. In FIG. 4, 2d1 is the rotor core which laminated | stacked the rotor iron plate C on the axial direction end surface of the rotor core 2a. FIG. 5 shows a plan view of the rotor iron plate C. FIG. Since the rotor iron plate C does not have a hole for embedding permanent magnets, one of the holes 3 for embedding permanent magnets is blocked by being laminated on the end face in the axial direction of the rotor core 2a.
[0021]
The axial end surface 11 of the permanent magnet 4 contacts the contact surface 12 of the rotor core 2d1 with the rotor core 2a, so that the leakage magnetic flux 10c1 at the axial end of the permanent magnet 4 rotates from the rotor core 2a. It passes through the core 2d1, passes through the rotor core 2a again, and returns to the permanent magnet 4. Further, since the permanent magnet 4 is attracted to the axial end face 12 of the rotor core 2d1, the permanent magnet 4 can be positioned in the axial direction only by the rotor core 2 without using a holder. Cost can be reduced.
[0022]
Further, one of the permanent magnet embedding holes 3 of the rotor core 2a is closed by the rotor core 2d1, so that both ends of the permanent magnet embedding holes 3 can be formed only by arranging one end plate 6 on the other. Can be closed. In the first embodiment, two end plates 6 are required, whereas in the second embodiment, only one end plate 6 is required, so that assembly and component costs can be further reduced.
[0023]
Moreover, the rotor iron plate A and the rotor iron plate C can be easily manufactured by performing control of taking in and out the tooth mold for punching the permanent magnet embedding hole 3 in the punching process. Since the tooth mold for punching out the magnetic flux short-circuit prevention hole 7 of the rotor iron plate B is not necessary, the configuration of the entire mold can be simplified.
[0024]
(Example 3)
FIG. 6 is an axial sectional view of a rotor of a permanent magnet type synchronous motor according to a third embodiment of the present invention. A rotor core 2c2 in which a rotor iron plate A is further laminated is disposed on the axial end face of the rotor core 2d2 on the side where the axial end face 11 of the permanent magnet 4 does not contact.
[0025]
When the axial end surface 11 of the permanent magnet 4 abuts on the axial end surface 12 of the rotor core 2d2, the leakage magnetic flux 10c2 at the axial end of the permanent magnet 4 passes from the rotor core 2a to the rotor core 2d2. It passes through the rotor core 2a again and returns to the permanent magnet 4. The leakage magnetic flux 10b2 passes from the rotor core 2a through the rotor core 2d2, further through the rotor core 2c2, across the permanent magnet embedding hole 3, and again, the rotor core 2c2, the rotor core 2d2, and the rotor core 2a. Return to the permanent magnet 4 through. Since the leakage magnetic flux 10b2 crosses the permanent magnet embedding hole 3, the magnetic resistance of the magnetic circuit through which the leakage magnetic flux 10b2 of the third embodiment passes is larger than the magnetic resistance of the magnetic circuit through which the leakage magnetic flux 10c1 of the second embodiment passes. The sum of the leakage flux 10c2 and the leakage flux 10b2 of the third embodiment is smaller than the leakage flux 10c1 of the second embodiment. Therefore, since the leakage magnetic flux can be reduced as compared with the second embodiment, the characteristics of the electric motor can be improved.
[0026]
Example 4
This will be described with reference to FIGS. FIG. 7 is an axial sectional view of a rotor of a self-starting permanent magnet synchronous motor according to a fourth embodiment of the present invention. In FIG. 7, 13 is a rotor and 14 is a rotor core. Reference numeral 14a denotes a rotor core in which the rotor iron plates D are stacked. FIG. 8 shows a plan view of the rotor iron plate D. In FIG. 8, 15 is a slot for arranging the conductor bar 16a of the starting cage conductor of FIG. 7, and 3 is a hole for embedding a permanent magnet. In FIG. 7, reference numeral 14 b denotes a rotor core in which the rotor iron plates E are stacked. FIG. 9 shows a plan view of the rotor iron plate E. In FIG. 9, reference numeral 17 denotes a slot for arranging the conductor bar 16a of the starting squirrel-cage conductor of FIG. 7, which has the same shape and the same position as the slot 15 of the rotor iron plate D of FIG. Reference numeral 7 denotes a magnetic flux short-circuit prevention hole, which is located at the same position as the permanent magnet embedding hole 3 of the rotor iron plate D shown in FIG. It is set narrower than P. In FIG. 7, 14c is a rotor core in which one or more rotor iron plates A are further laminated on the axial end surface of the rotor core 14b. Then, the conductor bar 16a and the short-circuit ring 16b are integrally formed by aluminum die casting to form a starting cage conductor. A self-starting permanent magnet type synchronous motor which operates as an induction motor at the time of starting by being provided with a squirrel cage conductor on the rotor 13 and operates as a synchronous motor by being drawn into the synchronous speed when reaching the vicinity of the synchronous speed. Will be constructed. In this case as well, the rotor core 14b having the magnetic flux short-circuit prevention hole 7 is disposed as in the first embodiment, and the rotor iron plate A is laminated. The leakage magnetic flux of the motor is reduced, and the characteristics of the electric motor can be improved.
[0027]
Also in the self-starting permanent magnet type synchronous motor provided with the starting squirrel-shaped conductor as in this embodiment, the rotor core 14 can be used without using a holder as in Embodiments 1 to 3 described above. Since only the permanent magnet 4 can be positioned in the axial direction, the cost of assembly and parts can be reduced.
[0028]
(Example 5)
Since the permanent magnet is formed of an Nd-Fe-B rare earth magnet, the Nd-Fe-B rare earth magnet has a high residual magnetic flux density, so that the volume of the rotor and the entire motor can be reduced. .
[0029]
In all of the above-described embodiments, the example of four poles is used. However, the present invention is not limited to this example, and the same applies to a rotor that forms another number of magnetic poles such as two poles.
[0030]
Further, in all the embodiments described above, the permanent magnet used is a flat magnet, but the present invention is not limited to this, and the same applies to a rotor using a permanent magnet having another shape such as an arc. .
[0031]
【The invention's effect】
As described above, according to the first aspect of the present invention, the rotor iron core is formed by stacking the rotor iron plates A having a plurality of permanent magnet embedding holes, and communicated with the permanent magnet embedding holes. One or more rotor iron plates B having holes for use are laminated on one of the axial end surfaces of the laminated rotor iron plates A, and the rotor iron plate A is attached to the axial end surface of the rotor iron plate B. The outer peripheral portion of the hole for embedding the permanent magnet in the contact surface of the rotor iron plate B with the rotor iron plate A is in contact with the axial end surface of the permanent magnet. As a result, the permanent magnet can be positioned in the axial direction using only the rotor core without using a holder, so that the cost of assembly and parts can be reduced.
[0032]
According to a second aspect of the present invention, the rotor core is formed by laminating the rotor iron plate A having a plurality of permanent magnet embedding holes, and does not have the permanent magnet embedding holes. The rotor iron plate C of the rotor iron plate C is formed by laminating one or a plurality of rotor iron plates C shaped to close the holes on one of the axial end surfaces of the laminated rotor iron plates A. Since the contact surface with A contacts the axial end surface of the permanent magnet, the permanent magnet can be positioned in the axial direction only by the rotor core without using a holder. The cost of parts can be reduced.
[0033]
Further, since one of the permanent magnet embedding holes is blocked by the rotor iron plate C, an end plate is disposed on the other axial end surface of the permanent magnet embedding hole to block the permanent magnet embedding holes. Thus, both ends of the permanent magnet embedding hole can be closed only by using a single end plate, so that the cost of assembly and parts can be further reduced.
[0034]
Further, the rotor iron plate A having the permanent magnet embedding holes and the rotor iron plate C closing the permanent magnet embedding holes can be easily controlled by taking in and out the tooth mold for punching the permanent magnet embedding holes in the punching process. Since it can be manufactured and a tooth mold for punching out the magnetic flux short-circuit prevention hole is unnecessary, the configuration of the entire mold can be simplified.
[0035]
According to the invention described in claim 2, the rotor iron plate C in the form of closing a permanent magnet embedding hole without have a hole for embedding the permanent magnets, the axial end surface of the side where the permanent magnet does not contact By laminating the rotor iron plate A having permanent magnet embedding holes, the magnetic resistance of the magnetic circuit between the NS surfaces at the axial end of the permanent magnet is increased, and the leakage magnetic flux can be reduced. The characteristics of the electric motor can be improved.
[0036]
According to a third aspect of the present invention, in addition to the first or second aspect of the present invention, a starting squirrel-cage conductor is disposed on the rotor core, whereby a self-starting permanent magnet type is provided. In addition to constituting the synchronous motor, the permanent magnet can be positioned in the axial direction only with the rotor core without using a holder, so that the cost of assembly and parts can be reduced.
[0037]
According to the invention described in claim 4 , in addition to the invention described in any one of claims 1 to 3 , a strong magnetic force can be obtained because the permanent magnet is formed of a rare earth magnet. Therefore, the volume of the rotor and the entire electric motor can be reduced.
[Brief description of the drawings]
FIG. 1 is an axial sectional view of a rotor according to an embodiment of the present invention. FIG. 2 is a plan view of a rotor iron plate A. FIG. 3 is a plan view of a rotor iron plate B. FIG. FIG. 5 is a plan view of a rotor iron plate C. FIG. 6 is an axial sectional view of a rotor according to an embodiment of the present invention. FIG. 8 is a plan view of a rotor iron plate D. FIG. 9 is a plan view of a rotor iron plate E. FIG. 10 is an axial cross sectional view of a conventional embedded rotor. Explanation】
DESCRIPTION OF SYMBOLS 1 Rotor 2 Rotor core 3 Permanent magnet embedding hole 4 Permanent magnet 7 Magnetic flux short-circuit prevention hole 8 Outer edge part of magnetic flux short-circuit prevention hole 9 End surface of permanent magnet in the axial direction

Claims (4)

An electric motor having a stator in which a winding is wound around a stator core, and a rotor that rotates rotatably facing an inner cylindrical surface of the stator core and in which a plurality of permanent magnets are embedded. ,
A rotor iron plate A having a plurality of holes for embedding permanent magnets in the rotor core is laminated more than the axial length of the permanent magnets to embed the permanent magnets,
In addition, the rotor iron plate B having the magnetic flux short-circuit prevention hole arranged so as to communicate with the permanent magnet embedding hole is positioned on one of the axial end surfaces of the laminated rotor iron plate A or the permanent magnet is positioned. Laminate as few as possible ,
Further, the rotor iron plate B is formed by laminating one or more of the rotor iron plates A on the axial end surface of the rotor iron plate B,
The outer edge portion of the magnetic flux short-circuit prevention hole in the contact surface between the rotor iron plate A and the rotor iron plate B in which the permanent magnet is embedded comes into contact with the axial end surface of the permanent magnet, thereby A permanent magnet type synchronous motor characterized by positioning the magnet in the axial direction. An electric motor having a stator in which a winding is wound around a stator core, and a rotor that rotates freely with respect to an inner diameter cylindrical surface of the stator core and in which a plurality of permanent magnets are embedded;
The rotor core is laminated with a rotor iron plate A having a plurality of permanent magnet embedding holes,
In addition, one or more rotor iron plates C that do not have the permanent magnet embedding holes and have a shape that closes the permanent magnet embedding holes are laminated on one of the axial end surfaces of the laminated rotor iron plates A. ,
The rotor iron plate C is formed by laminating the rotor iron plate A further having a permanent magnet embedding hole on the axial end surface on the side where the permanent magnet does not contact ,
A permanent magnet type synchronous motor characterized in that the permanent magnet is positioned in the axial direction by abutting a contact surface of the rotor iron plate C with the rotor iron plate A on an axial end surface of the permanent magnet. . 3. The permanent magnet type synchronous motor according to claim 1 , wherein a starting squirrel-cage conductor is disposed on the rotor core. The permanent magnet type synchronous motor according to any one of claims 1 to 3 , wherein the permanent magnet is formed of a rare earth magnet.

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