JP2851988B2 - Three-phase DC motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-phase DC motor having a flat structure.

[0002]

2. Description of the Related Art In recent years, electronic devices have been miniaturized, and there has been a strong demand for miniaturization and thinning of motors used as drive sources for various devices. Further, as the drive power supply voltage decreases, there is a demand for a motor capable of obtaining a higher torque than a current motor.

[0003] As a three-phase DC motor having a ring-shaped magnet having 2p magnetic poles on a plane and a coil in which 3m spiral unit coil poles are arranged in a plane opposite to the magnet, for example, Examples of such motors are disclosed in Japanese Unexamined Patent Publication Nos. 63-87145 and 1-170355. In such a motor, the relationship between the number of magnetic poles 2p and the number of coil poles 3m of the magnet is 2p: 3m = 4: 3. ing.
Then, the opening angles of the U-phase, V-phase and W-phase are set so that the coil pole of each phase is shifted by 120 ° in electrical angle from the coil pole of the other phase.
0 ° coil poles are arranged side by side.

[0004]

In the case of such a motor generally called a phase shift method, it is necessary to increase the number of turns of the spiral unit coil pole in order to increase the torque. However, when the number of turns is increased, the coil pole becomes large or the thickness is increased, so that miniaturization and thinning are prevented.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a small, thin, high-output three-phase DC motor capable of increasing the motor torque without increasing the coil pole or increasing its thickness. .

[0006]

In order to achieve such an object, the present invention provides a method of forming 2p (p is an integer of 3 or more) on a plane.
In a three-phase DC motor having a ring-shaped magnet having three magnetic poles and a coil in which 3 m (m is an integer of 2 or more) spiral unit coil poles arranged in a plane facing the magnet, Is 2p = 3m = 6k (k is an integer of 1 or more), and forms one phase among the 6k spiral unit coil poles. The 2k spiral unit coil poles include one or two spiral unit coil poles having an opening angle of about 120 ° in electrical angle, and a spiral unit having an opening angle of about 180 ° in electrical angle. And a unit coil pole.

[0007]

According to the present invention, the number of magnetic poles of the magnet is 2p (p
Is an integer of 3 or more) and the number of spiral unit coil poles is 3 m.
(Where m is an integer of 2 or more) can be set to 2p = 3m. That is, the number of coil poles can be made equal to the number of magnet poles. Therefore, as compared with the conventional phase shift type motor in which the ratio of the number of magnetic poles of the magnet to the number of coil poles is 4: 3, the number of coil poles for generating torque is increased. Thus, a three-phase DC motor having the same size and high torque can be obtained. In other words, it is smaller and smaller than a conventional motor that generates the same torque.
A thin three-phase DC motor can be provided.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows the configuration of an embodiment of a three-phase DC motor according to the present invention. Here, reference numeral 1 denotes a rotor magnet, which has twelve magnetic poles 1S and 1N in which a north pole and a south pole are equally magnetized alternately in the circumferential direction, as shown in FIG. One main surface of the rotor magnet 1 is a rotor plate 2
It is stuck to. The rotor plate 2 is fixed to a rotating shaft 4 via a sleeve 3. One end of the rotating shaft 4 is pivotally connected to a bearing 6 fixed to a center hole of the housing 5, and the other end is pressed against the opposing yoke 8 via a pivot receiver 7 by the magnetic force of the rotor magnet 1. ing. On the other main surface side of the rotor magnet 1, a flat coil 9 is arranged between the rotor magnet 1 and the opposing yoke 8 so as to face the rotor magnet 1 at a predetermined interval. As described above, the flat structure 3 shown in FIG.
A phase DC motor is configured.

Next, the flat coil 9 will be described. The flat coil 9 is composed of a plurality of spiral unit coil poles arranged on the same plane. In this embodiment, twelve spiral unit coil poles 34a to 34l of the same number as the number of magnetic poles of the rotor magnet 1 are arranged as shown in FIG.

In FIG. 3, 33a is a U-phase input terminal, 33b is a V-phase input terminal, 33c is a W-phase input terminal, and the coil poles 34a, 34b, 34c and 34d are U-phase input terminals. Phase, coil poles 34 e, 34 f, 34
g and 34 h are V phase, coil poles 34 i, 34
j, 34 k and 34 l become the W phase. Here, the opening angle of one magnetic pole of the rotor magnet 1 is 18 electrical degrees.
Assuming 0 ° (hereinafter referred to as “180 ° E”), in the U-phase coil pole, the coil poles 34 a and 34 d having an opening angle of 120 ° E or approximately 120 ° E become 180 ° E or approximately 180 °. ° E coil angles 34b and B3
4c, the coil poles 34e and 34h having an opening angle of 120 ° E or approximately 120 ° E are arranged at 180 ° E or approximately 180 ° E. Open-angle coil poles 34 f and 34 g
, The coils 34 i and 34 l having an opening angle of 120 ° E or approximately 120 ° E are 180 ° E or approximately 180 ° at the W-phase coil pole.
They are arranged adjacent to each other so as to sandwich the coil poles 34 j and 34 k having the opening angle of E. By arranging the twelve coil poles such that the coil poles of the same phase are adjacent to each other, the coil pole having an opening angle of 180 ° E or approximately 180 ° E among the coil poles of each phase is It can be arranged at a position shifted by 120 ° E from the coil pole having an opening angle of 180 ° E or substantially 180 ° E of the other phase.

Next, the back electromotive force (∝torque) of this embodiment is compared with the back electromotive force of a conventional three-phase DC motor.

FIG. 4 is a plan view showing the arrangement of spiral unit coil poles in a conventional phase shift type three-phase DC motor. Conventionally, as shown in FIG. 4, when the number of magnetic poles of the rotor magnet 1 is 12, nine spiral unit coils 42a to 42i having an opening angle of 180 ° E have an opening angle of 240.
° E (40 degrees) were arranged one by one in the area. Here, 41a is a U-phase input terminal, 41b is V
The phase input terminal 41c is a W phase input terminal, the coil poles 42a, 42d and 42g are U phase, the coil poles 42b, 42e and 42h are V phase, and the coil poles 42c and 42f. And 42 i become the W phase. As described above, conventionally, the U-, V-, and W-phase coil poles are arranged adjacent to each other so as to be shifted from the other-phase coil poles by 120 ° E.

FIG. 5A is an output curve of the back electromotive force obtained from the U-phase coil pole 42a among the coil poles of the conventional arrangement shown in FIG. Here, assuming that the peak value of the back electromotive force obtained from one coil pole is 1, FIG.
The peak value of (A) is 1. FIG. 5B shows the coil pole 4
2D and FIG. 5C are output curves of the back electromotive force obtained from the coil pole 42g, and the peak value of this output is also shown in FIG.
It becomes 1 similarly to (A). FIG. 5D is an output curve obtained by adding back electromotive forces obtained from all the U-phase coil poles 42a, 42d, and 42g, and the peak value of the output is 3. It is considered that the V phase and the W phase are similar to the U phase. Due to the three-phase driving, the added values of the back electromotive force of each phase are shifted from each other by 2 / 3π in electrical angle as shown in FIG. Therefore, the back electromotive force of the conventional three-phase DC motor m is a composite value of three output curves having a peak value of 3 and a 2π / 3 phase shift.

On the other hand, FIG. 6A is an output curve of the back electromotive force obtained at the U-phase coil pole 34a of this embodiment, and its peak value is 1. 6 (B) shows the coil pole 34b, FIG. 6 (C) shows the coil pole 34c, FIG.
(D) is an output curve of the back electromotive force obtained at the coil pole 34d, and the peak value of the output is 1 as in FIG. 6 (A). The phases of the output curves of the coil poles 34b and 34c are the same, and the coil poles 34b and 3c
4c, the output curve of the coil pole 34a is + π / 6, and the output curve of the coil 34d is −π.
The phase is shifted by / 6. FIG. 6E shows all the U-phase coil poles (34a, 34b, 3) of this embodiment.
4c and 34c are output curves of the sum of the back electromotive force obtained in d), the peak value of which is 3.732.
It is considered that the V phase and the W phase are similar to the U phase. Because of the three-phase driving, as shown in FIG. 6F, the added values of the back electromotive force of each phase are shifted from each other by 2π / 3 phase in electrical angle. Therefore, the peak value of the back electromotive force of this embodiment is 3.732.
Is a composite value of three output curves with a 2π / 3 phase shift.

As described above, in the present embodiment, a back electromotive force of 3.732 / 3 = 1.244 times as high as that of the conventional system can be obtained. That is, 1.244 times the torque can be generated.

In the above-described embodiment, the coil poles of the same phase are arranged adjacent to each other. However, such an arrangement can shorten the length of the connection line. However, the present invention is not limited to such an arrangement, and the arrangement of the coil poles may be any arrangement as long as the condition as the electric angle of the arrangement place is satisfied.

Next, by arranging one of the coil poles apart from the other coil poles of the same phase, the opening angle of three of the four coil poles of the same phase is set to 180 ° E. Another embodiment of the present invention capable of obtaining a larger torque than the above-described embodiment will be described.

FIG. 7 is a plan view showing the arrangement of spiral unit coil poles in another embodiment of the present invention. Here 75
a is a U-phase input terminal, 75 b is a V-phase input terminal, 7
5c is a W-phase input terminal. U phase coil pole is 76
a, 76 b, 76 c and 76 d,
Of these, three coil poles having an opening angle of 180 ° E or approximately 180 ° E are 76b, 76c, and 76d, and a coil pole having an opening angle of 120 ° E or approximately 120 ° E is one of 76a. Individual. V-phase coil poles are 76e and 76
f, 76 g and 76 h, of which three coil poles having an opening angle of 180 ° E or approximately 180 ° E are 76 f, 76 g and 76 h, and 12
A coil pole having an opening angle of 0 ° E or approximately 120 ° E has 76 poles.
e. The coil poles of the W phase are 76 i, 76
j, 76 k and 76 l, of which 1
A coil pole having an opening angle of 80 ° E or approximately 180 ° E has 76 poles.
j, 76 k and 76 l, 120 °
One of the coil poles having an opening angle of E or about 120 ° E is 76i. Here, only the coil pole 76l is arranged at a position distant from the other coils of the W phase.

FIG. 8A shows the U-phase coil pole 76 shown in FIG.
FIG. 8A shows an output curve of the back electromotive force obtained in FIG. 8A, where the peak value of the output of the back electromotive force obtained from one coil pole is 1. FIG. 8B shows an output curve of the back electromotive force obtained by the coil pole 76b, FIG. 8C shows an output curve of the coil pole 76c, and FIG. 8D shows an output curve of the back electromotive force obtained by the coil pole 76d. It becomes 1 similarly to FIG. Here, the coil poles 76b, 76c and 76
d has the same phase, and only the coil pole 76a has +
The phase is shifted by π / 6. FIG. 8E is an output curve obtained by adding back electromotive forces obtained at all the U-phase coil poles (76a, 76b, 76c, and 76d) in FIG. 7, and its peak value is 3.898. Becomes V phase, W
The phase can be considered similarly to the U phase. Because of the three-phase driving, the added values of the back electromotive forces of the respective phases are shifted from each other by 2π / 3 in electrical angle as shown in FIG. Therefore, the back electromotive force of the present embodiment is a composite value of three output curves having a peak value of 3.898 and a 2π / 3 phase shift.

As described above, in this embodiment, a back electromotive force of 3.898 / 3 = 1.299 times as high as that of the conventional system can be obtained. That is, 1.299 times torque can be generated.

When the coil of the present embodiment is a pattern coil formed by plating or etching, the thickness can be further reduced. Here, when using a pattern coil,
A plurality of layers having coil poles may be stacked.

Further, a sensor such as a Hall element may be arranged in a space other than the space in which the coil poles are arranged, and the coil poles may be partially deleted for purposes other than the parts arrangement. Preferably, the numbers are balanced between the phases.

The number of magnetic poles of the magnet is 2p and the number of coil poles is 3m
Is combined with 6 magnetic poles -6 in addition to the above-described embodiment.
There are coil poles, 18 magnetic poles-18 coils, 24 magnetic poles-24 coil poles, and the like.

Table 1 compares the peak values of the back electromotive force, that is, the torque, of the conventional motor of the phase shift type and the motor according to the present invention. As is clear from Table 1, according to the present invention, if the number of magnetic poles of the magnet is the same, higher torque can be obtained as compared with the conventional motor.

[0026]

[Table 1]

[0027]

As described above, according to the present invention, the torque of the motor can be increased without increasing the coil pole or increasing its thickness.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of an embodiment of the present invention.

FIG. 2 is a plan view showing a magnetized state of the rotor magnet 1 shown in FIG.

FIG. 3 is a plan view showing a configuration of a flat coil 9 shown in FIG.

FIG. 4 is a plan view showing an example of a configuration of a flat coil in a conventional example.

5 is an explanatory diagram of a back electromotive force in the conventional coil shown in FIG.

6 is an explanatory diagram of a back electromotive force in the coil according to the present invention shown in FIG.

FIG. 7 is a plan view showing a configuration of a flat coil according to another embodiment of the present invention.

FIG. 8 is an explanatory diagram of a back electromotive force in the coil according to the present invention shown in FIG. 7;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rotor magnet 1S, 1N Magnetic pole 9 Flat coil 33a-33c Input terminal 34a-34l Coil pole 75a-75c Input terminal 76a-76l Coil pole

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H02K 3/04 H02K 21/24 H02K 29/00

Claims (2)

(57) [Claims] 1. A ring-shaped magnet having 2p (p is an integer of 3 or more) magnetic poles on a plane, and 3m (m is an integer of 2 or more) spiral unit coil poles facing the magnet. In a three-phase DC motor having a coil in which is disposed in a plane, the number of magnetic poles 2p of the magnet and the number 3m of the spiral unit coil poles are 2p = 3m = 6k (k is an integer of 1 or more). Of the 6k spiral unit coil poles, 2k spiral unit coil poles forming one phase are one or two spiral unit coils having an opening angle of about 120 ° in electrical angle. And a spiral unit coil pole having an opening angle of about 180 ° in electrical angle.
Phase DC motor. 2. The at least two spiral unit coil poles of the 2k spiral unit coil poles forming one phase are arranged adjacent to each other. 3. The three-phase DC motor according to 1.