JPH104643A - Magnet rotor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnet rotor which has versatility and improved characteristics and can maintain high quality, by inserting magnets having lengths which are shorter than the lengths of the margins of housing holes, having margins formed in chorded states with respect to the circular arc which forms the outside diameter of an iron core into the housing holes. SOLUTION: A rotor is constituted, by inserting plate-shape magnets 3a into housing holes 2a, formed through the iron core 1a of the rotor, in the axial direction in parallel with an axial hole 9 by clearance fitting, press-fitting, etc., and covering both ends of the core 1a in the axial direction, by fixing end plates to both ends with a plurality of caulking pins, passed through the core 1a in the axial direction. Although the magnets 3a are rare-earth-type magnets which are magnetically oriented in parallel with the direction of the poles and so magnetized that the adjacent magnets mutually have differing polarities, the magnets 3a can be magnetized sufficiently at both end sections in the oriented direction, when the magnets 3a are magnetized by making a magnetizing current flow, because the magnets 3a are buried near the outer periphery of the core 1a. Therefore, a rotor which has versatility and improved characteristics and can maintain high quality can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adduction type rotor having a permanent magnet mounted thereon, such as a motor for driving a compressor of a refrigerator or an air conditioner, and more particularly, to a rotor in which a magnet is embedded inside an iron core. And a rotor of a so-called interior permanent magnet motor (hereinafter referred to as IPM).

[0002]

2. Description of the Related Art As a rotor of an IPM, one having a configuration shown in FIG. 7 is known. For example, see, for example, pp. 385-388 (Paper No. 306) of the 1995 IEEJ National Conference on Industrial Applications. It has been disclosed. This rotor is configured by providing a shaft hole 9 in a cylindrical iron core 11 and a plurality of housing holes 12 in parallel with the shaft hole 9, and inserting a plate-shaped magnet 13 into the housing hole 12.

[0003] The magnet 13 is a rare earth magnet such as an Nd-Fe-B magnet or the like, which is magnetically oriented parallel to the pole direction.
Adjacent magnets are magnetized so as to have mutually different polarities, and form a four-pole field in FIG. Also,
In the figure, reference numeral 14 denotes a magnetic flux short-circuit preventing portion, which is formed by a space connected to the housing hole 12 or a non-magnetic material is inserted into this space as needed, so that the gap between the poles of each magnet 13 is magnetically prevented. To prevent the amount of magnetic flux from being reduced by the magnet.

The rotor is arranged in a stator having three-phase windings to constitute a permanent magnet type synchronous motor, and rotates by exciting the stator windings via an inverter. ing. In the case of such an IPM, since it is characterized by reverse saliency, in a low speed range, so-called maximum torque control is performed in which the motor is driven at the maximum torque points of both the reluctance torque generated thereby and the main magnetic flux torque generated by the magnet. In the high-speed region, it is effective to perform so-called advance phase control for supplementing the main magnetic flux torque with the reluctance torque, and is used for driving the above-described compressor and the like.

That is, in general, the torque T of the IPM is T = T1 + T2 (1) where T1 is the main magnetic flux torque and T2 is the reluctance torque, and the magnetic flux amount by the magnet is Φ, the q-axis current is Iq, d Assuming that the axis current is Id, the q-axis inductance is Lq, and the d-axis inductance is Ld, T1 = Φ · Iq (2) T2 = (Ld−Lq) Id · Iq (3)

[0006]

SUMMARY OF THE INVENTION An IP as shown in FIG.
In the rotor of M, the magnet 13 is embedded near the center of the iron core 11. This is because the core part interposed between the magnet and the air gap is positively utilized to provide a reluctance torque component. This is for performing control in which the ratio occupied by is set large. Therefore, with respect to the IPM using such a rotor, the component of the q-axis current Iq described in the above equations (2) and (3) is small, and d
An inverter configured to increase the component of the shaft current Id (hereinafter, referred to as an inverter mainly based on the Id component) is used.

However, in order to construct such an inverter, components such as a microcomputer and a current sensor are expensive, so that the Iq
In fact, there is a great demand for a low-cost inverter (hereinafter, referred to as an inverter mainly composed of Iq components) configured to reduce the Id component by increasing the amount of the Id component. Driving the rotor shown in FIG. 7 by such an inverter mainly composed of the Iq component leads to a state in which the characteristics of the IPM are deteriorated or the IPM cannot be driven. In other words, the conventional rotor as shown in FIG. 7 has a very poor versatility.

In the case of manufacturing an IPM rotor, if the magnet 13 is magnetized in advance, the workability of assembling the rotor before rotation will be significantly deteriorated due to its strong magnetic force. After mounting all the magnets on the magnet 11, a magnetizing current is applied to the stator winding or the dedicated magnetizing winding arranged outside the rotor, so that all the magnets are simultaneously attached to a predetermined number of poles. It is magnetized.

In this case, the rotor shown in FIG. 7 will be described. As shown in FIG. 8, the magnetic orientation of the magnet 13 is formed parallel to the direction of the pole as shown by the solid arrow 15. The magnetizing magnetic flux forms a flow which is considerably inclined with respect to the magnetic orientation 15 at both ends of the magnet corresponding to the vicinity of the gap between the poles of the magnetizing magnetic field, as indicated by a broken arrow 16. This phenomenon becomes more remarkable as the magnet 13 is embedded closer to the center of the iron core 11. As a result, the magnetization of both ends of the magnet becomes insufficient, the magnetic force of the completed magnet is reduced, and the characteristics of the IPM are deteriorated. Will be. In addition, since the quality of the magnetic force of the rotor is not stable, the values of the q-axis inductance Lq and the d-axis inductance Ld vary, and the matching with the inverter is deteriorated. is there.

[0010]

According to the present invention, a cylindrical core is provided with a shaft hole in the center thereof, a plurality of receiving holes are provided in parallel with the shaft hole, and a plate-like magnet is inserted into the receiving hole. The present invention relates to a magnet rotor constituted by In a cross section perpendicular to the axial direction, the accommodation hole has a hole edge formed in a chord shape with respect to an arc forming the outer diameter of the iron core. A magnet formed to have a length less than the length is inserted.

[0011]

The accommodation holes including the magnetic flux short-circuit preventing portion are linearly arranged at each pole, so that the magnet is embedded near the outer periphery of the iron core, and the amount of magnetic flux by the magnet can be increased. Further, by changing the length of the magnet, the ratio between the main magnetic flux torque component and the reluctance torque component can be easily changed while keeping the iron core shape as it is. Further, the inclination of the magnetized magnetic flux at both ends of the magnet can be made gentle.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A rotor according to the present invention will be described with reference to the drawings.
FIG. 1 shows a first embodiment of the present invention, and shows a cross section perpendicular to the axial direction of a rotor. This rotor is supported by a shaft inserted into the shaft hole 9 and is disposed inside a motor stator fixed to a casing or the like, and an outer peripheral portion of the iron core 1a is located between the outer peripheral portion of the stator core and an inner peripheral portion of the stator core. It is comprised so that it may oppose via a predetermined space | gap. The iron core 1a is formed by laminating a large number of thin iron plates having a thickness of 0.35 mm, 0.50 mm or the like stamped into a predetermined shape. It is configured to be fixed by well-known caulking clamp means 7 which is fitted and fixed between the iron plates.

The iron core 1a is provided with a plurality of housing holes 2a penetrating in the axial direction in parallel with the shaft hole 9.
A plate-like magnet 3a is inserted into the a by a loose fit or press-fitting, and thereafter, the end plates are fixed to both ends in the axial direction by a plurality of caulking pins 8 penetrating through the iron core 1a in the axial direction. A rotor is configured. The magnet 3a is a rare-earth magnet such as an Nd-Fe-B-based magnet magnetically oriented parallel to the pole direction, and is magnetized so that adjacent magnets have different polarities. A field is formed.

As shown in FIG. 2, the receiving hole 2a is formed by hole edges 6a and 6c and 6b and 6d formed in chords with respect to an arc forming the outer diameter of the iron core 1a. I have. Between the straight hole edges 6a and 6c, and 6b
And 6d are provided with a protrusion 5 protruding in the direction of narrowing the hole width, and by being positioned by the protrusion 5, formed with a length less than the length of the linear portion of the hole edge. Magnet 3a is inserted into the center of accommodation hole 2a. As a result, spaces 4 as magnetic flux short-circuit preventing portions are formed at both ends of the accommodation hole 2a by the hole edges 6c and 6d, and the gap between the poles of each magnet 3a is magnetically short-circuited to reduce the amount of magnetic flux by the magnet. Is prevented.

As described above, the accommodating holes 2a of the respective poles are provided linearly, and the accommodating holes accommodate the magnets 3a having a length less than the lengths of the hole edges 6a and 6c or 6b and 6d. A magnetic flux short-circuit preventing portion 4 can be provided between the poles, and at the same time, the magnet 3a is embedded near the outer periphery of the iron core 1a. Therefore, the amount of magnetic flux Φ in the above equation (2) can be increased, and the main magnetic flux torque T1 can be increased, so that the inverter can be driven by the Iq component-based inverter without any problem. Of course, it can be driven without any trouble by an inverter mainly composed of the Id component.

In order to further improve the efficiency of the IPM when driven by an inverter mainly composed of the Id component,
It is necessary to increase the reluctance torque T2 in the equation (3), and the most effective configuration is to increase the absolute value of (Ld-Lq). Therefore, this case can be dealt with as a configuration as shown in FIG. The iron core 1a of the rotor shown in FIG. 5 is the same as the iron core shown in the embodiment of FIGS. 1 and 2, and the magnet 3b formed shorter than the magnet 3a of FIGS. Is housed. In this case, the magnet 3b is positioned by the non-magnetic spacer 10b so as to be located at the center of the magnetic pole. By configuring like the rotor of FIG. 5, the amount of magnetic flux Φ by the magnet of the rotor is reduced, so that the stator magnetic flux passing through the iron core 1a is increased, and the reluctance torque component can be increased. An advantage of this configuration is that it can be dealt with only by changing the magnet type without changing the type of the iron core 1a.

In the rotor shown in FIG. 1, since the magnet 3a is embedded near the outer peripheral portion of the iron core 1a as described above, a stator winding or a dedicated magnetizer disposed outside the rotor is provided. As shown in FIG. 6, when a magnetizing current is applied to the winding to magnetize it, the magnetizing magnetic flux 16 is generated at both ends of the magnet 3a corresponding to the vicinity of the gap between the magnetizing magnetic fields. The inclination with respect to the direction becomes gentle. This is because the magnet 3a is located closer to the magnetic pole of the magnetized winding by being disposed outside the position of the conventional magnet 13 indicated by a broken line in FIG. Sufficient magnetization along the direction is achieved.

FIG. 3 shows another embodiment of the present invention.
The rotor in FIG. 3 has a hole edge 6 at the center of the accommodation hole 2b.
The hole edges 6e and 6f at both ends are formed stepwise in the direction of reducing the hole width with respect to the holes a and 6b, and the magnet 3a is positioned by the stepped portions. If the width of the magnetic flux short-circuit preventing portion 4 is obtained to such an extent that the function is not hindered, the same operation and effect as those of the rotor shown in FIG. Also, when using the short magnet 3b as shown in FIG. 5, it can be easily analogized that the rotor can be configured in the same manner as in FIG.

FIG. 4 shows still another embodiment of the present invention, in which the accommodating hole 2c is formed by the hole edges 6g and 6h of the rotor accommodating hole 2a shown in FIG.
Is formed. In this case, by inserting the non-magnetic spacer 10a into the magnetic flux short-circuit preventing portion 4, the magnet 3a similar to FIG. 2 can be positioned and mounted at the center of the magnetic pole, and the same operation and effect can be obtained. Can be
The case where the short magnet 3b as shown in FIG. 5 is used can be dealt with by adjusting the length of the non-magnetic spacer 10a.

[0020]

According to the present invention, a versatile rotor can be obtained which can be driven by not only an inverter mainly composed of an Id component but also an inverter mainly composed of an Iq component without any problem, and a low-cost controller can be used. It is what becomes. Also IPM
In the case of pursuing high efficiency, there is a feature that a rotor having a configuration most suitable for each inverter can be easily formed by changing only the magnet type without changing the iron core type.

Further, since the magnet is sufficiently magnetized, there is no shortage or variation in magnetic force at the time of completion and the quality is stabilized, and the q-axis inductance and d
The value of the shaft inductance is stabilized and the matching with the inverter is improved, and as a result, the characteristics of the IPM can be improved and its quality can be maintained.

[Brief description of the drawings]

FIG. 1 is a plan sectional view of a rotor showing a first embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is an enlarged plan sectional view of a main part of a rotor showing a second embodiment of the present invention.

FIG. 4 is an enlarged plan cross-sectional view of a main part of a rotor showing a third embodiment of the present invention.

FIG. 5 is an enlarged plan sectional view of a main part of a rotor according to a fourth embodiment of the present invention.

FIG. 6 is an explanatory diagram showing a magnetic flux flow during magnetization.

FIG. 7 is a plan sectional view of a rotor showing a conventional example.

FIG. 8 is an explanatory diagram showing a relationship between a magnetic orientation of a magnet and a magnetized magnetic flux.

[Explanation of symbols]

 1a, 1b, 1c, 11 Iron cores 2a, 2b, 2c, 12 Housing holes 3a, 3b, 13 Magnets 4, 14 Magnetic flux short-circuit prevention parts 5 Projections 6a to 6h Hole rims 7 Caulking clamp means 8 Caulking pins 9 Shaft holes 10a, 10b Non-magnetic spacer

Claims (1)

[Claims] 1. A magnet rotor comprising a cylindrical core having a shaft hole at the center thereof, a plurality of housing holes parallel to the shaft hole, and a plate-shaped magnet inserted into the housing hole. A cross section perpendicular to the axial direction of the accommodation hole has a hole edge formed in a chord shape with respect to an arc forming the outer diameter of the iron core,
A magnet rotor, wherein a magnet formed to a length less than the length of the chordal hole edge is inserted into the accommodation hole.