JPH08308195A - Three-phase motor - Google Patents

Abstract

PURPOSE: To reduce the uneven rotation of a three-phase motor by winding coils around a prescribed number of adjacent magnetic poles composed of a ferromagnetic material so that the polarities of the magnetic poles can alternately change and different-phase coils around the magnetic poles at both ends. CONSTITUTION: U-phase coils are wound around pole pieces(PP) 101-104 in alternately changing polarities and the numbers of turns of the coils wound around the PPs 101 and 104 are adjusted to the halves of those of coils wound around the PPs 102 and 103. V-phase coils are wound around PPs 104-107 in alternately changing polarities, with the one wound around the PP 104 being wound on the U-phase coil. The number of turns of the coils wound around the PPs 105 and 106 are made equal to those of the coils wound around the PPs 102 and 103, but the numbers of turns of the coils wound around the PPs 104 and 107 are adjusted to the halves of those of the coils wound around the PPs 102 and 103. Then W-phase coils are wounds around PPs 107-101 in alternately changing polarities, with the one wound around the PP 107 being wound on the V-phase coil. The numbers of turns of the coils wound around the PPs 108 and 109 are made equal to those of the coils wound around the PPs 102 and 103, but the numbers of turns of the coils wound around the PPs 107 and 101 are adjusted to the halves of those of the coils wound around the PPs 108 and 109.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-phase motor, and more particularly to a three-phase motor with reduced uneven rotation.

[0002]

2. Description of the Related Art Conventionally, three-phase motors having various structures have been proposed for the purpose of reducing cogging torque and downsizing the motor structure. US Patent 4,7
The three-phase motor disclosed in Japanese Patent Publication No. 74,428 has 3 (2
It has a stator having pole pieces as (n + 1) magnetic poles and a rotor having permanent magnets having 3 (2n + 1) ± 1 magnetic poles. However, n is a positive integer.

A stator 20 of this three-phase motor has a cross-sectional view showing the outline of the motor shown in FIG. 4 and 2n + 1 poles continuous for each phase A, B and C as shown in the stator winding diagram of FIG. It is wound so as to excite the pieces Ai, Bi, Ci.

However, the stator 2 wound in this way
At 0, the electromagnetic force generated between the rotor 21 and the rotor 21 at the time of excitation during rotation is biased to one side in the axial direction. As a result, there is a problem that uneven rotation occurs due to the imbalance.

A three-phase motor disclosed in Japanese Patent Laid-Open No. 3-117354, which has been proposed as a method for reducing the imbalance of the electromagnetic force described above, is a sectional view showing an outline of the motor shown in FIG. 6 and a stator shown in FIG. As shown in the winding diagram, the stator 3
A part of 2n + 1 pieces of the 0 pole pieces 41 to 49 is distributed to the pole pieces in the substantially opposite direction and winding is performed. In FIG. 6, reference numeral 31 indicates a rotor having a permanent magnet.

[0006]

However, when the stator 30 wound like the three-phase motor disclosed in Japanese Patent Laid-Open No. 3-117354 is applied, the torque generated in each pole piece is as follows. Since the phases are largely deviated, there is a problem that the effective value of the combined torque becomes small.

For example, FIG. 3 shows that for each three-phase motor,
FIG. 7 is a diagram showing a combined torque ratio (vertical axis) given by sin φ with a horizontal axis representing a relative electrical angle θ, in which the combined torque of the three-phase motor disclosed in US Pat. No. 4,774,428. It is represented by the ratio Ta and is represented by the combined torque ratio Tb of the three-phase motor disclosed in Japanese Patent Laid-Open No. 3-117354.

The composite torque ratio Ta of the three-phase motor disclosed in the above-mentioned US Pat. No. 4,774,428 is given by sin φ of the following equation: sin φ = (sin θ + sin (θ + 20 °) + sin (θ + 40 °)) / 3, the peak value OP of the combined torque ratio in this case is
It is 0.96 and the effective value RMS is 0.68.

On the other hand, the combined torque ratio Tb of the three-phase motor disclosed in Japanese Unexamined Patent Publication No. 3-117354 is given by sin φ of the following equation, sin φ = (sin θ + sin (θ + 20 °) + sin (θ + 100 °)) / 3 Becomes The peak value OP of the combined torque ratio in this case is
0.74, the effective value RMS is 0.52,
It can be seen that the combined torque ratio Ta of the three-phase motor disclosed in U.S. Pat. No. 4,774,428 is significantly reduced.

The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to provide a three-phase motor which can secure a large effective value of the combined torque and has less uneven rotation. To do.

[0011]

The three-phase motor of the present invention comprises:
If n is 1 or an integer greater than or equal to 3 (2
A stator provided with (n + 1) ferromagnetic magnetic poles, a rotor provided with permanent magnets having 3 (2n + 1) ± 1 magnetic poles which are alternately different magnetic poles, and a mounting means for attaching the stator and the rotor so as to be relatively rotatable. In the above stator, coils of each phase are wound around 2n + 2 ferromagnetic magnetic poles adjacent to each other with alternating polarities, and 2n + 2 strong magnetic poles adjacent to each other. Among the magnetic poles, coils of different phases are wound around the ferromagnetic poles at both ends.

[0012]

In the above three-phase motor, the coils of the respective phases are wound around the 2n + 2 ferromagnetic magnetic poles adjacent to each other with alternating polarities, and the coils of different phases are provided on the ferromagnetic magnetic poles at both ends. Since it is wound, the range in which torque is generated is expanded, and uneven rotation is small.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of a three-phase motor showing an embodiment of the present invention, and FIG. 2 is a diagram showing a winding state around a pole piece which is each magnetic pole of a stator of the three-phase motor of the present embodiment. Is.

The three-phase motor of this embodiment includes a casing (not shown) and a stator 1 arranged on the inner surface of the casing.
And a rotor 3 mounted inside the stator 1 with a permanent magnet 2 fixed around a rotating shaft (not shown). At both ends of the casing, a housing (not shown) as a mounting means in which bearings (not shown) are arranged is attached. The housing may be directly attached to both ends of the stator by omitting the casing.

On the rotor 3, a ring-shaped permanent magnet 2 made of a material such as neodymium-iron-boron and magnetized to 8 poles in the radial direction is attached around the rotating shaft. The number of poles 8 is n = 1 when the number of poles is (3 (2n + 1) -1).
Is the value obtained as. These permanent magnets 2 are magnetized so that adjacent magnetic poles have different magnetic poles. It is held so as to be rotatable relative to the stator 1.

In the stator 1, nine pole pieces 101 to 109 serving as ferromagnetic magnetic poles protruding in the inner diameter direction are formed at equal intervals in the circumferential direction.
A slot 12 is formed between 1 to 109. It should be noted that the number of poles 9 is n when the number of poles is 3 (2n + 1).
= 1. The nine pole pieces 101 to 109 have substantially the same width and are made of a ferromagnetic material, and their inner peripheral portions are separated from the magnetic poles of the permanent magnet 2 by an annular radial gap 13.

As shown in FIG. 2, the U-phase coil of the three phases is continuously wound in alternating polarities from the first pole piece 101 to the fourth pole piece 104. At this time, the number of turns of the first pole piece 101 and the fourth pole piece 104 is half the number of turns of the second pole piece 102 and the third pole piece 103.

Next, the V-phase coil is wound continuously from the fourth pole piece 104 to the seventh pole piece 107 in alternate polarities. At this time, the U-phase coil has already been wound around the fourth pole piece 104, but the V-phase coil is wound over it. Since the number of turns at this time is half that of the pole pieces 102 and 103, the total of the U phase and the V phase is the pole pieces 102 and 10.
The number of turns is the same as 3. However, the winding directions are opposite in the U phase and the V phase. This pole piece 104 also serves as a U-phase and V-phase pole piece.

The fifth pole piece 105 and the sixth pole piece 106 are pole pieces in which only the V-phase coil is wound, and the number of turns is the pole piece 102,
Same as 103. And the seventh pole piece 10
Since 7 is a pole piece that is also used for the W phase, the number of turns of the V phase coil is half that of the pole pieces 105 and 106.

The W-phase coil is the seventh pole piece 10
The 7th to 1st pole piece 101 is continuously wound by an alternating polarity. At this time, the pole piece 108,
In 109, only the W-phase coil is wound, and the pole piece 1
The number of turns is the same as 02 and 103, and the pole piece 10
7 and 101 are respectively shared with the V phase and the U phase, and the number of turns of the W phase is half that of the pole pieces 108 and 109.

As described above, the coils of the respective phases are wound around four pole pieces adjacent to each other in alternating polarities, and in the pole pieces at both ends of the four pole pieces adjacent to each other, It has a structure that doubles as the pole pieces at both ends of the four pole pieces of coils of different phases.

Further, the combined torque ratio (vertical axis) Tc of the three-phase motor of this embodiment with respect to the relative electrical angle θ shown in FIG.
Given by sin φ, sin φ = ((sin θ) / 2 ＋ sin (θ ＋ 20 °) ＋ sin (θ ＋ 40 °)
+ Sin (θ + 60 °) / 2) / 3, which is the peak value O of the combined torque ratio of the motor of this embodiment.
P is 0.95 and the effective value RMS is 0.67.

The value of the combined torque ratio does not decrease like the combined torque ratio Tb of the conventional three-phase motor disclosed in Japanese Patent Laid-Open No. 3-117354, and the above-mentioned conventional US Pat. Compared to the combined torque ratio Ta of the three-phase motor disclosed in Japanese Patent No. 428, it is only slightly reduced.

Therefore, according to the three-phase motor of the present embodiment, as described above, the coils of each phase are dispersed into four pole pieces, and the number of windings of the pole pieces at both ends where the phase shift becomes large is set to the center. Since the number of halves of the two pole pieces is half, uneven rotation can be reduced and the torque is hardly reduced.

The present invention is not limited to the above-mentioned embodiments, and the design can be changed without departing from the gist of the present invention. For example, in the above embodiment, the rotor 3 is the stator 1
However, the rotor may be arranged outside the stator. In this case, the pole pieces are formed outward, and the outer circumferences of the pole pieces are separated from the magnetic poles of the permanent magnet by an annular radial gap.

In the above-described embodiment, the winding direction is clockwise in FIG. 2, but the winding direction may be counterclockwise, and the first pole piece of each phase is counterclockwise. It is a winding, but this may also start with a clockwise winding.

(Additional Note) Based on the above embodiment,
The invention having the following configuration is derived. That is, (1) When n is 1 or an integer larger than that,
A rotor provided with 3 (2n + 1) ferromagnetic magnetic poles, a stator provided with permanent magnets having 3 (2n + 1) ± 1 magnetic poles that are alternately different magnetic poles, and a rotor and a stator are attached so as to be rotatable relative to each other. A three-phase motor having mounting means, wherein in the rotor, coils of respective phases are wound around 2n + 2 ferromagnetic poles adjacent to each other with alternating polarities, and 2n + adjacent to each other.
A three-phase motor in which coils of different phases are wound around the ferromagnetic magnetic poles at both ends of the two ferromagnetic magnetic poles. In the above three-phase motor, it is possible to reduce uneven rotation without significantly reducing the torque.

(2) A stator having nine ferromagnetic magnetic poles, a rotor having permanent magnets having eight magnetic poles which are alternately different magnetic poles, and a mounting means for mounting the stator and the rotor so that they can rotate relative to each other. In the above stator, coils of each phase are wound around four ferromagnetic magnetic poles adjacent to each other with alternating polarities and four strong adjacent magnetic poles are provided. A three-phase motor characterized in that coils of different phases are wound around the ferromagnetic magnetic poles at both ends of the magnetic poles. In the above three-phase motor, it is possible to reduce uneven rotation without significantly reducing the torque.

[0029]

As is apparent from the above description, in the three-phase motor according to claim 1 of the present invention, the coils of each phase are 2n + 2.
Since the coils of different magnetic poles are overlapped and wound around the magnetic poles at both ends of the ferromagnetic magnetic poles, it is possible to reduce uneven rotation without significantly reducing the torque. The three-phase motor according to claims 2 and 3 of the present invention is the above-mentioned claim 1.
It has the effect of the described three-phase motor, and in particular, it is possible to reduce uneven rotation.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a three-phase motor showing an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a winding state of the three-phase motor shown in FIG.

FIG. 3 is a diagram showing combined torque ratio characteristics of the three-phase motor of FIG. 1 and a conventional three-phase motor.

FIG. 4 is a schematic configuration diagram of a conventional three-phase motor.

5 is a schematic diagram showing a winding state of the three-phase motor of FIG.

FIG. 6 is a schematic configuration diagram of another conventional three-phase motor.

7 is a schematic diagram showing a winding state of the three-phase motor of FIG.

[Explanation of symbols]

 1 .... Stator 101 to 109 ..... Pole piece (ferromagnetic magnetic pole) 2 ..... Permanent magnet 3 ..... Rotor U phase, V phase, W phase ... Each phase coil

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[Submission date] June 16, 1995

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Claims (3)

[Claims] 1. When n is an integer of 1 or more, a stator having 3 (2n + 1) ferromagnetic magnetic poles and 3 (2n + 1) ± 1 magnetic poles alternately different from each other. A three-phase motor having a rotor provided with a permanent magnet having magnetic poles, and a mounting means for mounting the stator and the rotor so as to be rotatable relative to each other, wherein in the stator, coils of each phase are 2n + 2 strongly adjacent to each other. Of the 2n + 2 ferromagnetic magnetic poles that are wound around the magnetic poles with alternating polarities and are adjacent to each other, the ferromagnetic poles at both ends are wound with coils of different phases. A three-phase motor. 2. The three-phase motor according to claim 1, wherein the number of turns of the coil wound around each of the 3 (2n + 1) ferromagnetic poles is substantially the same. 3. The three-phase motor according to claim 1, wherein n = 1.