JPH1146464A - Permanent magnet motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the driving efficiency when a rotor is rotated, by housing the rotor provided with permanent magnets in the space formed in the central part of a stator in such a manner that the rotor is rotatable, and sequentially energizing windings in a plurality of phases placed so that the rotor is encircled with the windings. SOLUTION: A plurality of circumferential iron cores 15 are installed in contact with the surfaces of permanent magnets 5 on the stator 2 side. A pair of through holes 13, 13 penetrating each of the circumferential iron cores 15 in the direction of the axis of a rotor 1, are formed in the areas between the permanent magnets 5 and the stator 2 on each of the circumferential iron cores 15. The pairs of the through holes 13, 13 are symmetrically positioned on both the sides of the magnetic center of magnetic lines of force generated between the permanent magnets 5 and the stator 2. Each of the through holes 13, 13 is in slit shape, and they are arranged in dogleg shape with the intervals between them getting narrower as they go toward the stator 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotor having permanent magnets, which is rotatably accommodated in a space formed in the center of a stator, and is provided with a plurality of phases surrounding the rotor. The present invention relates to a permanent magnet motor that rotates a rotor by sequentially energizing windings.

[0002]

2. Description of the Related Art FIG. 5 shows the structure of a conventional permanent magnet motor, in which a cylindrical rotor (10) is rotatable in a space formed in the center of a cylindrical stator (2). Is housed in The stator (2) includes a ring-shaped stator core (21), and an inner peripheral surface of the stator core (21) surrounds the rotor (10), and the rotor (10) 24 slots penetrating in the axial direction
(22a), (22b) and (22c) are recessed at equal intervals. Specifically, a U-phase slot (22a), a V-phase slot (22b), and a W-phase slot (22c) are repeatedly recessed two by two in a counterclockwise direction. And U-phase slot (22a), V-phase slot
(22b) and W-phase slot (22c), respectively,
A phase winding (24) and a W-phase winding (25) are wound.

On the other hand, a rotor (10) is composed of a shaft (14a) having a square cross section and four corners of the shaft (14a).
Four arms extending toward (14b) (14b) (14b) (14b)
And a central iron core (14). The central iron core (14) is formed by laminating a large number of thin iron pieces.
The output shaft (3) is located at the center of the shaft (14a) of the central iron core (14).
Is fixed therethrough. On the outer peripheral surface of the shaft portion (14a), four permanent magnets (5), (5), (5), which surround the output shaft (3), have a rectangular cross-sectional shape, and are magnetized in the radial direction.
(5) is fixed. Here, adjacent permanent magnets (5)
(5) is magnetized in opposite directions.

[0004] The stator of the permanent magnet (5) (5) (5) (5)
(2) On the surface on the side, an outer peripheral iron core (1
5) (15) (15) (15) is fixed and the outer peripheral iron core (15) (1
5) and the arm part (14b) of the central iron core (14), the connecting iron core (16)
Are connected to each other. Between the arm portion (14b) of the central iron core (14) and the outer peripheral iron core (15), the outer peripheral iron core (1
An air gap (12) is formed to reduce the magnetic flux leakage from 5) directly to the arm (14b). The outer core (1
5) and the connection iron core (16) are formed by laminating a large number of thin plate-like iron pieces, similarly to the center iron core (14).

In the above-described permanent magnet motor, a U-phase winding (23) and a V-phase winding (2
4) The V-phase winding (24) and the W-phase winding (25), the W-phase winding (25) and the U-phase winding (23) are repeatedly energized sequentially. As a result, an electromagnetic force based on Fleming's left hand rule is generated in the energized winding in relation to the lines of magnetic force generated from the permanent magnet (5) and penetrating the winding, and the electromagnetic force causes the rotor (10 ) Will rotate.

[0006]

FIG. 6 shows the distribution of the lines of magnetic force when the largest rotational torque is generated in the rotor (10) when the permanent magnet motor is driven. The magnetic field radiation surface and the energized W-phase winding (25) and U-phase winding (23) face each other. In this state,
The maximum rotational torque acts on the rotor (10) by the electromagnetic force generated in the W-phase winding (25) and the U-phase winding (23). However, in the permanent magnet motor, the magnetic lines of force generated from the permanent magnet (5) spread radially as shown in the figure and pass through the V-phase winding (24) which does not contribute to the rotation of the rotor (10). As a result, there is a problem that high efficiency cannot be obtained due to this loss. An object of the present invention is to provide a permanent magnet motor with higher efficiency than before.

[0007]

According to the present invention, there is provided a permanent magnet motor including a rotor provided in a space formed in a central portion of a stator.
(1) is rotatably housed, and the stator (2) includes:
At a plurality of positions surrounding the rotor (1), a multi-phase winding extending in parallel with the rotation axis of the rotor (1) is disposed.
In (1), a plurality of permanent magnets (5) magnetized in a radial direction perpendicular to the rotating shaft are disposed at a plurality of positions surrounding the rotating shaft, and the respective permanent magnets (5) are fixed. A plurality of outer peripheral iron cores (15) are disposed in contact with the surface on the side of the child (2), and the rotor (1) is rotated by sequentially energizing the windings of the plurality of phases. Each permanent magnet (15) has a permanent magnet
In the area sandwiched between (5) and the stator (2), the magnetic field lines generated between each of the permanent magnets (5) and the stator (2) are focused on the central part of the outer peripheral iron core (15). A low magnetic permeability portion is formed.

[0008] In the permanent magnet motor according to the present invention,
Since the magnetic permeability lines of the low magnetic permeability portion are harder to pass than other regions of the outer peripheral iron core (15), the magnetic lines of force generated between each permanent magnet (5) and the stator (2) are formed by the outer peripheral iron core (15). Focus on the center of 15).
As a result, most of the magnetic lines of force generated from the permanent magnet (5) penetrate through the energized windings, and a large electromagnetic force is generated in the energized windings. A large rotation torque is generated in (1). As a result, the rotor (1) is efficiently rotated.

[0009] Specifically, the low magnetic permeability portion is provided at each outer peripheral iron core.
(15) is constituted by a pair of through holes (13) and (13) opened through the rotor (1) in the axial direction, and the pair of through holes (13) and (13)
Are arranged on both sides of the magnetic center line of the magnetic force generated between each permanent magnet (5) and the stator (2).

In this specific configuration, since air has a lower magnetic permeability than the iron core, a pair of through holes (13) and (13) constitutes a low magnetic permeability portion, and each permanent magnet (5 ) And stator
The lines of magnetic force generated during (2) converge in a region sandwiched between the pair of through holes (13) (13). According to this specific configuration, a low magnetic permeability portion can be formed by a simple configuration in which two through holes (13) and (13) are provided in the outer peripheral iron core (15).

More specifically, the pair of through holes (13) (1)
3), each of which has an elongated slit shape in a cross section orthogonal to the rotation axis of the rotor (1), and has a smaller interval toward the stator (2). According to this specific configuration, the effect of converging the lines of magnetic force can be further enhanced, and as a result, the rotor (1) can be driven to rotate more efficiently.

[0012]

According to the permanent magnet motor of the present invention,
Since a large rotational torque is generated by effectively utilizing the magnetic lines of force generated from the permanent magnets, the driving efficiency is improved as compared with the related art.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings. As shown in FIGS. 1 and 2, the permanent magnet motor of this embodiment has a cylindrical stator.
In the space formed in the center of (2), a cylindrical rotor (1)
Are rotatably accommodated. Stator of this embodiment (2)
Is exactly the same as the conventional one shown in FIG. 5, and surrounds the rotor (1) on the inner peripheral surface of the ring-shaped stator core (21) and penetrates in the axial direction of the rotor (1). 24 slots (22a) (22b)
(22c) are recessed at equal intervals. A U-phase winding (23), a V-phase winding (24), and a W-phase winding (25) are wound around these slots (22a), (22b), (22c), respectively.

On the other hand, the rotor (1) of this embodiment has one central iron core (14), four outer peripheral iron cores (15), (15), (15) (15), and both iron cores (14). (15) to each other (16) (16) (16)
(16), and these iron cores (14), (15), (16) are formed by laminating a large number of thin plate-shaped iron pieces (not shown). The central iron core (14) has a shaft section (14a) having a square cross section, and the shaft section.
4 extending from the four corners of (14a) toward the stator (2)
The output shaft (3) is fixed to the center of the shaft (14a) through the arm (14b) (14b) (14b) (14b). On the outer peripheral surface of the shaft portion (14a), four permanent magnets (5) having a rectangular cross-sectional shape surrounding the output shaft (3) are provided.
(5), (5) and (5) are fixed. Each permanent magnet (5) is magnetized in the radial direction, and the magnetizing directions of the adjacent permanent magnets (5) are opposite to each other.

The outer peripheral iron cores (15), (15), (15) and (15) each have a fan-shaped cross-sectional shape, and have a stator (2) for permanent magnets (5) (5) (5) (5).
Fixed on the side surface. Adjacent outer core (15) (1
5) and the arm part (14b) of the central iron core (14), the connecting iron core (16)
Between the outer peripheral iron core (15) and the arm part (14b) of the central iron core (14), and directly from the outer peripheral iron core (15) to the arm part (14b). An air gap (12) for reducing the leakage magnetic flux is formed.

Each permanent magnet is attached to the outer peripheral iron core (15).
A pair of through holes (13) and (13) penetrating in the axial direction of the rotor (1) is formed in an area sandwiched between the stator (5) and the stator (2). A low magnetic permeability portion for converging the lines of magnetic force generated during (2) to the center of the outer peripheral iron core (15) is formed. The pair of through holes (13) and (13) are symmetrically opened on both sides with respect to the magnetic center line of the magnetic force generated between each permanent magnet (5) and the stator (2). In the cross section orthogonal to the output shaft (3), each has an elongated slit shape, and the interval between them decreases toward the stator (2), so that it has a C shape. Since the pair of through holes (13) and (13) have a lower magnetic permeability than other regions of the outer peripheral iron core (15), it is difficult for the magnetic force lines to pass through. Therefore, most of the magnetic lines of force generated from the permanent magnet (5) are converged between the pair of through holes (13) and (13) and pass through the outer peripheral iron core (15) as shown in FIG. 23), (24), and (25).

In the permanent magnet motor, a U-phase winding (23) and a V-phase winding (24),
The V-phase winding (24) and the W-phase winding (25), the W-phase winding (25) and the U-phase winding (23) are sequentially and repeatedly energized. For example, in FIG. 3, when the W-phase winding (25) and the U-phase winding (23) are energized, a magnetic field line distribution as shown is formed, and the W-phase winding (2
An electromagnetic force based on Fleming's left hand rule is generated in the 5) and U-phase windings (23) in relation to the lines of magnetic force passing through these windings (23) and (25). Here, most of the magnetic lines of force generated from the permanent magnet (5) are, as shown, a W-phase winding (25) and a U-phase winding (23).
Through the U-phase winding (2) as shown in FIG.
3) It is possible to obtain an electromagnetic force larger than before, which is distributed and penetrates the V-phase winding (24) and the W-phase winding (25). Due to this large electromagnetic force, a large rotational torque is generated in the rotor (1). Similarly, the other three permanent magnets (5), (5), (5), and the W-phase winding (25) and the U-phase winding (23) opposed by the permanent magnets (5), (5), (5). With respect to the relationship (1), a large electromagnetic force is obtained, and a large rotational torque is generated in the rotor (1). These rotation torques are combined to rotate the rotor (1).

Next, when the energization of the W-phase winding (25) and the U-phase winding (23) is switched to the energization of the U-phase winding (23) and the V-phase winding (24), each permanent The magnet (5) faces the energized U-phase winding (23) and V-phase winding (24). Thereby, similar to the relationship between the W-phase winding (25) and the U-phase winding (23), most of the magnetic force lines generated from the permanent magnet (5) are changed to the U-phase winding (23) and the V-phase winding. A large rotating torque is generated through the winding (24). In this manner, by sequentially energizing the adjacent two-phase windings, a large rotating torque is continuously generated, and the rotation of the rotor (1) is continued.

FIG. 4 shows how a large rotating torque can be obtained in the above-described permanent magnet motor in relation to the distribution of lines of magnetic force generated from the permanent magnet. FIG.
The distribution of the lines of magnetic force generated from the permanent magnet in the range of the electrical angle of 360 degrees, FIG. 3B shows the waveform of the current flowing through the one-phase winding, and FIG. (D) shows the waveform of the total rotation torque generated in the rotor due to the current flowing through the three-phase windings.

In the conventional permanent magnet motor, the lines of magnetic force generated from the permanent magnet (5) spread radially, and the distribution of the lines of magnetic force is as shown by the broken line in FIG. It has a trapezoidal distribution that spreads to both sides of the section (electrical angle 120 degrees), and the magnetic lines of force that spread to both sides of the energized section penetrate the windings that are not energized, so there is no rotational torque, and the leakage flux Had become. On the other hand, in the permanent magnet motor of the present invention, as described above, the lines of magnetic force generated from the permanent magnets are converged by the pair of through holes, and the distribution of the lines of magnetic force is as shown by the solid line in FIG. Same figure
The distribution is compressed in the current-carrying section shown in (b), and the leakage magnetic flux spreading on both sides of the current-carrying section is significantly reduced as compared with the conventional case.
As a result, most of the magnetic force lines generated from the permanent magnets penetrate through the current-carrying winding, and as shown by the solid line in FIG. can get.

The rotation torque shown in FIG. 3C is generated for each of the three-phase windings, and these rotation torques
Since there is a phase difference of 0 degrees, the total rotational torque obtained by summing these rotational torques has a flat distribution as shown by the solid line in FIG. 4D, and is larger than the conventional total rotational torque shown by the broken line. Become. As described above, in the permanent magnet motor of the present invention, the lines of magnetic force generated from the permanent magnets (5) effectively act on the windings to generate a large rotational torque on the rotor (1). Efficiency is improved.

The configuration of each part of the present invention is not limited to the above embodiment, and various modifications can be made within the technical scope described in the claims. For example, in the above embodiment, the present invention is applied to the permanent magnet motor having the three-phase windings (23), (24), (25), but is not limited thereto.
The present invention is also applicable to a permanent magnet motor having windings of a plurality of phases or more. Further, in the above-described embodiment, the present invention is applied to the permanent magnet motor including four permanent magnets (5), (5), (5), and (5). The present invention is also applicable to a permanent magnet motor having a plurality of permanent magnets other than four.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a structure of a permanent magnet motor of the present invention.

FIG. 2 is a perspective view showing the structure of the above.

FIG. 3 is a diagram showing a distribution of lines of magnetic force generated from a permanent magnet in FIG.

FIG. 4 is a waveform diagram comparing the distribution of lines of magnetic force generated from a permanent magnet and the rotational torque obtained thereby with the present invention and the related art.

FIG. 5 is a cross-sectional view illustrating a structure of a conventional permanent magnet motor.

FIG. 6 is a diagram showing a distribution of lines of magnetic force generated from permanent magnets in FIG. 5;

[Explanation of symbols]

 (1) Rotor (12) Air gap (13) Through hole (14) Central iron core (15) Outer peripheral iron core (16) Connecting iron core (2) Stator (21) Stator iron core (22a) U Phase slot (22b) V phase slot (22c) W phase slot (23) U phase winding (24) V phase winding (25) W phase winding

Claims (4)

[Claims] A permanent magnet (5) is disposed on a rotor (1), and an outer peripheral iron core (15) is provided on a stator (2) side of the permanent magnet (5).
In the permanent magnet motor provided with, the outer peripheral iron core (15)
, A permanent magnet motor in which a low magnetic permeability portion for forming a magnetic flux generated between a permanent magnet (5) and a stator (2) at a central portion of an outer peripheral iron core (15) is formed. 2. A stator (2) comprising a rotor (1) rotatably housed in a space formed at the center of the stator (2).
, A plurality of phase windings extending parallel to the rotation axis of the rotor (1) are disposed at a plurality of positions surrounding the rotor (1).
The rotor (1) is provided with a plurality of permanent magnets (5) magnetized in a radial direction orthogonal to the rotation axis at a plurality of positions surrounding the rotation axis, and each permanent magnet (5). A plurality of outer peripheral iron cores (15) are disposed in contact with the surface of the stator (2) side of the rotor (1).
In the permanent magnet motor that rotates
In the area between the permanent magnets (5) and the stator (2), the lines of magnetic force generated between the permanent magnets (5) and the stator (2) are applied to the outer core (15). Permanent magnet motor having a low magnetic permeability portion for focusing at the center of the motor. 3. The low magnetic permeability part comprises a pair of through holes (13) formed by penetrating each outer peripheral iron core (15) in the axial direction of the rotor (1).
(13), and the pair of through-holes (13) and (13) are arranged on both sides of a magnetic center line of magnetic force lines generated between each of the permanent magnets (5) and the stator (2). The permanent magnet motor according to claim 1 or 2, wherein 4. The pair of through holes (13) (13) are
4. The permanent magnet motor according to claim 3, wherein each of the cross sections perpendicular to the rotation axis of (1) has an elongated slit shape, and a distance between the sections decreases toward the stator (2). 5.