JP2012223009A - Rotor for magnet-embedded rotary machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an IPM motor with high output.SOLUTION: A magnet-embedded rotary machine 1 comprises an armature with a coil 9 and a rotor 3 housing a plurality of permanent magnets 6 which are arranged in the coil 9 to face the armature with a gap therebetween so that magnetic fluxes interlink, in a slot 4 of a rotor core 5, and the armature and the rotor 3 can be relatively rotated with electric conduction to the coil 9. In the rotor 3, the permanent magnet 6 is Nd-based rare earth permanent magnet in a rectangular shape, and the ratio of the magnetization direction thickness in the permanent magnet occupied in the width of the permanent magnet magnetization direction in the slot 4 is secured at 90% or more.

Description

  The present invention relates to a synchronous permanent magnet rotating machine such as a motor or a generator, and a rotor for an embedded magnet rotating machine in which a permanent magnet is embedded in a rotor, and an embedded magnet rotating machine including the rotor. It is.

  A magnet-embedded rotating machine (generally an IPM motor) in which a permanent magnet is embedded inside a rotor can obtain a reluctance torque in addition to a magnet torque caused by the attractive force / repulsive force of a coil and a permanent magnet. Compared to a surface magnet type motor (SPM motor) in which a magnet is attached to the outer peripheral surface of the rotor, the torque is high and the efficiency is high. Therefore, this magnet-embedded rotary machine is used in a compressor such as a drive motor, an air conditioner, a refrigerator, a freezer, or a showcase of a hybrid vehicle or an electric vehicle that requires high output performance.

  As shown in FIG. 5, a typical IPM motor 100 includes a permanent magnet 106, a rotor core 105, a stator core 107, and a coil 109, and supplies a three-phase AC sine wave current to an armature coil 109 fixed to the stator core 107. As a result, the rotor 103 rotates by the reluctance torque in addition to the magnet torque caused by the attractive force / repulsive force between the coil 109 and the permanent magnet 106.

  As shown in FIG. 6, the rotor 103 is provided with a slot hole 104 having a certain size for embedding a permanent magnet. The slot hole size is determined so that the permanent magnet 106 can be inserted without any problem. However, if the hole size is relatively large compared to the permanent magnet, the gap 113 between the rotor core slot and the magnet is used. There is a problem that the output becomes large and the output greatly decreases.

  An object of the present invention is to provide a high output IPM motor.

  In order to achieve the above object, according to the present invention, an armature having a coil, and a plurality of permanent magnets arranged to face the armature with a gap so that magnetic flux interlinks in the coil are slots in a rotor core. A rotor of an embedded magnet type rotary machine in which the armature and the rotor are relatively rotatable by energizing the coil, wherein the permanent magnet has a rectangular shape. Provided is a rotor for an embedded magnet type rotating machine, which is an Nd-based rare earth permanent magnet, and the ratio of the thickness of the permanent magnet in the magnetization direction width to the permanent magnet magnetization direction width of the slot is ensured to be 90% or more.

  In the rotor for embedded magnet type rotary machine according to the present invention, since the gap between the permanent magnet and the rotor core slot is small, the magnetic efficiency as a magnetic circuit is relatively improved, and as a result, the motor output is also improved.

  The motor of the present invention has a permanent magnet magnetization direction thickness dimension tolerance of ± 0.05 mm and a magnetization direction thickness dimension tolerance of the permanent magnet insertion slot of the rotor core of ± 0.1 mm. A high output motor is provided by securing a thickness ratio of 90% or more in the direction.

  As can be understood from the above description, according to the rotor for embedded magnet motor of the present invention, the clearance between the permanent magnet and the rotor core slot can be reduced by accurately finishing the dimensional tolerance when manufacturing the permanent magnet and the rotor core slot. In addition, a high output IPM motor can be provided, and its utility value is extremely high in the industry.

It is a top view which shows the one aspect | mode of the IPM motor which concerns on this invention. It is an expanded sectional view of the slot part provided in the rotor core of FIG. It is a graph which shows the correlation with the clearance gap between a magnet-magnetic steel plate, and the reduction rate of the induced voltage of an IPM motor. It is a graph which shows the correlation with the reduction rate of magnet thickness and an induced voltage. It is a top view which shows the conventional typical IPM motor. FIG. 6 is an enlarged cross-sectional view of a slot portion provided in the rotor core of FIG. 5.

Hereinafter, the present invention will be described in more detail with reference to the drawings.
FIG. 1 shows an embodiment of an embedded magnet motor (IPM) 1 of the present invention. The rotor 3 forms a rotor core 5 having a slot 4 by laminating a disk-shaped electromagnetic steel plate or dust core having four rectangular through holes and a shaft insertion hole so that the positions of the through holes are aligned. . A shaft (not shown) is inserted into the shaft insertion hole of the rotor core and rotatably supports the rotor core. In each slot, a prismatic permanent magnet 6 is inserted and fixed to form a magnetic pole. Of the four surfaces perpendicular to the paper surface of each permanent magnet, the surface facing the stator and the opposite surface correspond to the magnetic pole surface, that is, the surface perpendicular to the magnetization direction.
In the illustrated example, the pole faces of adjacent permanent magnets are arranged so as to be perpendicular to each other, and each permanent magnet forms one pole, but the slot is divided into two in a V shape in plan view, Alternatively, two poles may be formed without being divided into two, and one pole may be formed as a set of two permanent magnets to be accommodated.

  The rotor 3 includes a tooth in the hollow portion of the cylindrical stator core 7, that is, a hollow portion formed by a plurality of teeth 8 projecting radially inward from a substantially annular stator yoke in plan view. It is arranged so as to be rotatable apart. Concentrated windings are wound around each tooth 8 to form a coil 9.

FIG. 2 shows a detailed view of the rotor core slot portion of one embodiment of the magnet-embedded motor 1 of the present invention. The permanent magnet 6 is disposed so as to contact the magnetic pole surface along the wall surface closest to the shaft insertion hole (inner side in the radial direction) among the inner wall surfaces of the slot 4 of the rotor core 5, and farthest from the shaft insertion hole (diameter A slot-inserting electromagnetic steel sheet 11 is arranged along the wall surface (outside in the direction). As a result, in each slot 4 of the rotor core 5, a certain gap 13 exists between the permanent magnet 6 and the electromagnetic steel plate 11 for slot insertion.
The material of the electromagnetic steel plate 11 for slot insertion may be the same as or different from the material used for the rotor core 5.

The motor 1 is manufactured and measured by the rotor 3 shown in FIGS. 1 and 2, and the permanent magnet 6 disposed so that the magnetic pole surface is in contact with the radially inner surface of the inner wall surface of the slot 4 of the rotor core 5. The influence of the magnetization direction thickness ratio of the permanent magnet 6 in the magnetization direction width on the motor output was confirmed. The actually evaluated motor was forcibly rotated by an external drive motor, and the no-load induced voltage was measured with a power meter. Motor cord source stator, a rotor both length 55 mm, the stator core outer diameter Fai110mm, the rotor core outer diameter Fai55mm, permanent magnet 55mm (L) × 30mm (W ) × 21mm: is (T magnetizing direction thickness) . The rotor core slot size is 30 mm (W) × 3 mm (T: thickness direction in the direction of magnetization of the permanent magnet), and the constant gap between the rotor core pocket and the permanent magnet is the radially outer surface of the inner wall surface of the slot 4. It adjusted by changing the thickness of the electromagnetic steel plate 11 for slot insertion arrange | positioned so that it may contact | connect. The coil 9 is 200 turns at each tooth 8 and has a three-phase one-star connection with two phases in parallel. The material of the rotor core 5 and the stator core 7 is 35A300 (space factor 95%), and the permanent magnet 6 has a residual magnetic flux density of 1.3T. A material having a coercive force (Hcj) of 1700 kA / m was used.

  As an evaluation method, the motor was forcibly rotated at 3000 rpm, and evaluation was performed with a no-line induced voltage between lines. The parameters in the thickness direction of the electromagnetic steel sheet 11 were changed at an arbitrary step size from 0 mm (non-insertion) to 1 mm. The result is shown in FIG. The horizontal axis in FIG. 3 is the gap between the permanent magnet and the rotor core slot, and the vertical axis is the no-load induced voltage reduction ratio when the no-load induced voltage is 100% when the gap between the permanent magnet and the rotor core slot is 0 mm. Show. As can be understood from the figure, it has been found that the reduction ratio of the no-load induced voltage has a first-order correlation with respect to the gap between the permanent magnet and the rotor core slot. Note that the gap was calculated from the average value by measuring several dimensions of the rotor core slot in the magnet thickness width direction, the magnet thickness, and the thickness of the electromagnetic steel sheet for insertion in units of parts.

  FIG. 4 shows the result of rewriting the horizontal axis of the graph of FIG. 3 to the thickness ratio of the permanent magnet magnetization direction in the rotor core slot. As can be understood from the figure, the no-load induced voltage reduction ratio is within 10% when the thickness ratio of the permanent magnet magnetization direction is 90% or more. As can be seen from this result, if the thickness ratio of the permanent magnet in the magnetization direction width of the permanent magnet in the rotor core slot is 90% or more, the no-load induced voltage reduction ratio is within 10%, and the high output motor It was found that characteristics were obtained.

  The gap between the permanent magnet and the rotor core slot where the no-load induced voltage decay ratio according to this embodiment falls within 10% corresponds to 0.3 mm. If this is assigned to the dimensional tolerance of each material, it can be understood that the dimensional tolerance of the permanent magnet magnetization direction is ± 0.05 mm or less, and the width dimension of the permanent magnet magnetization direction of the rotor core pocket is ± 0.1 mm or less. Is a level that can be realized by a process of manufacturing a normal permanent magnet or a rotor core electromagnetic steel sheet.

  As can be seen from the above-described measurement evaluation results, the motor output increases as the ratio of the thickness of the permanent magnet in the magnetization direction width of the rotor core slot increases. In other words, if the dimensional tolerance of the permanent magnet magnetization direction width of the rotor core slot and the dimensional tolerance of the permanent magnet magnetization direction are highly accurate, a motor with higher output can be obtained. From the results of the present example, when the thickness ratio of the permanent magnet in the permanent magnet magnetization direction width of the rotor core slot is 90% or more, the no-load induced voltage reduction ratio is within 10%, and a high output motor can be obtained. .

  According to the motor having the rotor of the present invention incorporating the above-described permanent magnet and rotor core, the motor performance is improved, and a recent hybrid vehicle, an electric automatic drive motor, an air conditioner, a refrigerator / freezer, or a show It is suitable for a compressor such as a case.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the basic configuration is not limited to this embodiment, and there are design changes and the like without departing from the gist of the present invention. However, they belong to the technical scope of the present invention.

1,100 Embedded magnet rotating machine (IPM motor)
3, 103 Rotor 4, 104 Slot 5, 105 Rotor core 6, 106 Permanent magnet 7, 107 Stator core 8 Teeth 9, 109 Coil 11 Magnetic steel sheet 13, 113 for slot insertion

Claims (2)

An armature having a coil, and a rotor in which a plurality of permanent magnets arranged to face the armature with a gap so that magnetic flux interlinks in the coil is housed in a slot of a rotor core, A rotor of a magnet-embedded rotating machine in which an armature and the rotor can relatively move by energizing a coil;
The rotor for a magnet-embedded rotary machine, wherein the permanent magnet is a rectangular Nd-based rare earth permanent magnet, and the ratio of the thickness of the permanent magnet in the magnetization direction to the width of the permanent magnet in the slot is 90% or more.   2. The rotor according to claim 1, wherein a dimensional tolerance of the magnetization direction of the permanent magnet is ± 0.05 mm or less and a dimensional tolerance of a width of the permanent magnet magnetization direction of the slot is ± 0.1 mm or less.

Images