JP2000102197A - Motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor producing high torque by reducing cogging. SOLUTION: A motor 10 is constituted of a shaft 11, a stator 30 fixed to the shaft 11, and a rotor 20 disposed so as to rotate around the shaft 11 against the stator 30. The rotor 20 has a magnet 23 so formed as to have 10×(n) magnetic poles ((n) is a natural number). The stator 30 holds a ring 33 fixed to a stator housing 31 and an insulator 35 wound with a coil 36, with its one end fixed to the ring 33 and the other end formed with a salient pole section 34b. The salient pole section 34b has an iron core 34 which constitutes a magnetic circuit together with the magnet 23 of the rotor 20. The magnetic core 34 is so disposed as to have 12×(n) magnetic poles ((n) is a natural number).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a motor, and more particularly to a motor capable of improving the rotation efficiency of the motor and obtaining a high torque.

[0002]

2. Description of the Related Art In order for a motor to rotate efficiently and uniformly, it is necessary to prevent cogging from occurring. The cogging means a repulsive force acting in the direction opposite to the rotation direction when the polarity of the magnetic field generated by the iron core matches the polarity of the magnetic field generated by the magnet. When cogging occurs, the rotation torque of the motor fluctuates, causing unevenness in the rotation of the motor. In order to prevent this cogging, conventionally, a skew angle is provided in the magnetic field of the iron core or the magnet to generate another cogging having a phase opposite to that of the generated cogging so that the cogging is eliminated.

[0003]

However, in order to provide a skew angle with respect to the iron core, winding must be performed while forming a skew angle when winding the coil. There is a problem. Further, the coil provided with the skew angle has a poor winding space factor, so that there is a problem that a large torque cannot be obtained when rotating the motor. Further, providing a skew angle on the magnet to prevent cogging has a problem in that the shape of the magnet becomes complicated, and it is difficult to manufacture a motor.

Accordingly, an object of the present invention is to provide a motor which solves the above-mentioned problems, reduces cogging and obtains a high torque.

[0005]

According to a first aspect of the present invention, there is provided a shaft, a stator fixed to the shaft, and a rotatable arrangement about the shaft with respect to the stator. The rotor comprises a magnet having a number of poles of 10 × n (n is a natural number), and the stator is fixed to a stator housing. Ring and
Holding the insulator on which the coil is wound, one end is fixed to the ring, the other end forms a salient pole portion, and the salient pole portion connects the magnet and the magnetic circuit of the rotor. And an iron core constituted by a motor arranged such that the number of poles of the iron core is 12 × n (n is a natural number).

According to the configuration of the first aspect, the number of poles of the iron core is one.
2 × n (n is a natural number), the number of magnet poles is 10 × n
(N is a natural number). In addition, a natural number means a positive integer not including 0. Thereby, the torque fluctuation of the motor caused by the cogging can be suppressed small, and the rotation unevenness and the vibration of the motor can be suppressed small. Further, since the ring and the iron core are formed separately, compared to the case of integrally molding, there is less waste of material at the time of pressing, and the cost of the motor can be reduced.

According to a second aspect of the present invention, in the configuration of the first aspect, the height of the salient pole portion of the iron core is substantially the same as the height of the magnet. Achieved. According to the configuration of the second aspect, since the height of the magnet is formed to be substantially the same as the height of the iron core, it is possible to prevent cogging from increasing and to obtain a high torque.

[0008] According to a third aspect of the present invention, the above object is attained by the motor of the first aspect, wherein the width of the coil increases toward the outer peripheral surface. According to the configuration of the third aspect, by increasing the number of windings of the coil toward the outer peripheral surface side of the coil, it is possible to effectively use the coil space and obtain a high torque.

[0009] According to a fourth aspect of the present invention, in the configuration of the first aspect, the coil is wound so that a winding direction of two adjacent coils is reversed, and the coil is electrically connected. This is achieved by a motor connected in series to form a coil pair, and the coil pairs are connected in parallel. According to the configuration of the fourth aspect, the coils having the adjacent phase difference of 30 ° in electrical angle are connected in series, so that the connection can be facilitated without a disadvantage such as a loss due to a minor loop current. Further, by connecting the coil pairs in parallel, it is possible to realize a low resistance at a wire diameter capable of forming an aligned winding having a wire diameter of 0.6 mm, for example, and to reduce copper loss.

[0010]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Note that the embodiments described below are preferred specific examples of the present invention,
Although various technically preferable limits are given, the scope of the present invention is not limited to these modes unless otherwise specified in the following description.

FIG. 1 is a sectional view showing a preferred embodiment of the motor of the present invention. The motor 10 will be described in detail with reference to FIG. The motor 10 shown in FIG. 1 is used, for example, in an electric vehicle, and includes a shaft 11, a rotor 2
0, stator 30 and the like. Bearings 12 and 12 are fixed to the stator 30, and the shaft 11 is fixed to the bearings 12 and 12 by shrink fitting or press fitting. The rotor 20 is rotatably held on a shaft 11 via bearings 12 and 12.

FIG. 2 shows a configuration diagram of the rotor 20, and the rotor 20 will be described in detail with reference to FIGS. The rotor 20 of FIG.
It has a yoke 22, a magnet 23, and the like. FIG.
(A) The rotor housing 21 has a through hole 2 at its center.
The shaft 11 is inserted into the through hole 20a. As shown in FIG. 2B, the rotor housing 2
1, a yoke 22 is disposed, and a magnet 23 is fixed to the yoke 22. Magnet 23 is S
The poles and the N poles are formed alternately, and the number of poles is 10 ×
It is formed to have n poles. The magnet 23 shown in FIG. 2B has, for example, 30 poles. The magnet 23 forms a magnetic circuit with an iron core 34 described later, and the rotor 20 is rotated by the magnetic circuit. Further, a magnet holder 24 for generating an energization signal is phase-fixed to the rotor housing 21 and fixed by screws or the like.

Next, the stator 30 will be described in detail with reference to FIG. 1 includes a stator housing 31, a stator core 32, and the like. FIG.
A through hole 31a is formed in the stator housing 31a, and the bearings 12, 12 are fixed to the through hole 20a. A stator core 32 is fixed to the stator housing 31 by screws or the like. A driver board 37 is fixed to the stator housing 31, and a discharge plate made of, for example, a MOSFET is fixed to the driver board by screws or the like.

FIG. 3 is a plan view showing the periphery of the stator core 32. As shown in FIG. The stator core 32 in FIG.
The ring 33 is composed of an iron core 34, an insulator 35, a coil 36, and the like. The ring 33 fixes and holds 12 × n (n is a natural number) iron cores on the outer peripheral surface. Ring 33
By dividing and forming the iron core 34, compared with the case of integrally molding, the portion for discarding the material at the time of pressing is reduced, and the cost of the motor can be reduced. Also,
The iron core 34 fixed to the ring has three phases (U phase, W phase,
V phase), and drive currents having different phases are supplied for each of the three phases. Two adjacent iron cores among the iron cores are electrically connected in series and form the same phase.

However, the coils 36 held by the two adjacent iron cores 34 are arranged so that the winding directions are reversed. As a result, the connection can be facilitated without adverse effects such as loss due to the minor loop current. That is, when all the coils 36 are connected in parallel,
Since a minor loop current flows between the coils and loss occurs, it is necessary to prevent this loss by devising the connection method, but just connect the coils with opposite winding directions in series,
Generation of a minor loop current can be prevented. The coil pairs connected in series for each phase are connected in parallel. Thereby, it is possible to wind a copper wire having a wire diameter of 0.6 mm, for example, in which aligned winding can be performed.
Resistance can be reduced.

The iron core 34 holds an insulator 35, and a coil 36 is wound around the insulator 35. When the core 34 is fixed to the ring 33, the coil 36 is wound around the insulator 35, and then the core 34 is inserted into the insulator 35 and fixed. Thereby, the winding operation of the coil 36 is facilitated, the winding can be performed at a high winding space factor, and a high torque can be obtained.

FIG. 4 is a plan view showing the shape of the ring 33. In FIG. 4A, the ring 34 has a recess 33a formed on the outer peripheral surface thereof. This recess 33a is shown in FIG.
As shown in (B), for example, it is formed in a substantially trapezoidal shape, and one end of the iron core 34 is press-fitted or welded into the recess 33a and fixed. FIG. 5 is a view showing the shape of the iron core 34. In FIG. 5 (A), a protrusion 34a is formed at one end of the iron core 34, and this shape is almost the same as the recess 33a of FIG. 4 (B). It has the shape of The core 34 is fixed to the ring 33 by fixing the protrusion 34 a to the recess 33 a. Further, a salient pole portion 34b is formed at the other end of the iron core 34, and the salient pole portion 34b is arranged to face the magnet 23 to form a magnetic circuit.
Also, as shown in FIG. 1, the height h of the salient pole portion 34b is formed so as to be substantially the same as the width of the ring 33 and the width of the magnet 23. Thereby, high torque can be obtained while minimizing cogging.

FIG. 6 shows an insulator 35 and a coil 36.
FIG. 7 is a configuration diagram showing an insulator 35 with reference to FIG.
And the coil 36 will be described in detail. The insulator 35 shown in FIG. 6 is formed in a tubular shape, and includes a tubular portion 35a, a hollow portion 35b, locking pieces 40, 41, 42, 43, and the like. FIG. 6A shows a top view of the insulator 35. In FIG. 6A, an iron core 34 is inserted into a hollow portion 35b of the insulator 35, and the insulator 35 is held by the iron core 34. FIG. 6B shows a front view of the insulator 35, and FIG.
In (B), a coil 36 is formed by winding a copper wire or the like by aligned winding on the cylindrical portion 35a. That is, after the copper wire is held by the locking piece 35b, the cylindrical portion 35
The coil 36 is formed so as to be substantially parallel by being wound around a and finally being held by the locking piece 35c. Thereby, the winding space factor of the coil 36 can be increased.

Next, with reference to FIGS.
The operation example will be described in detail. First, when a drive current is supplied to the coil 36 of FIG. 1, the coil 36 forms a magnetic field. Then, the magnetic field formed by the coil 36 and the magnetic field formed by the magnet 23 form a magnetic circuit, and the rotor 20 is rotated by the magnetic circuit. Here, the number of coggings generated during one rotation of the motor 10 is determined by the least common multiple of the number of poles of the iron core 34 and the number of poles of the magnet 23. Since the least common multiple of the number 12 × n of the iron cores 34 and the number of poles 10 × n of the magnet 23 is 60 × n, cogging occurs 60 × n times. In FIG. 5, when n = 3, for example, 180 times of cogging occurs, and as the number of times of cogging increases, the fluctuation due to the cogging can be suppressed. Therefore, when the cogging occurs 180 times, the fluctuation becomes small, and the motor 10 can be smoothly rotated to suppress the vibration.

The reason why the number of poles of the iron core 34 is a multiple of 12 and the number of poles of the magnet 23 is a multiple of 10 is as follows. Generally, motors having the number of magnet poles of 2n or 4n (n is a natural number) for the pole number 3n (n is a natural number) of the iron core 34 are mainstream. How to provide,
There are a method of forming a groove in the iron core, a method of providing an auxiliary pole between the iron cores, and the like. However, when the coil is wound around the iron core 34 by using the ring 33 and the iron core 34 as separate members as in the motor 10 of FIG. Therefore, a high torque can be obtained and cogging cannot be reduced because of a trade-off between the torque and the torque.

Therefore, the number of poles of the iron core 34 and the magnet 23
Was changed to increase the least common multiple thereof to reduce cogging. Specifically, first, a combination of the number of poles of the iron core and the number of poles of the magnet that does not have the trade-off described above is considered. Furthermore, when the coil pairs are connected in parallel to reduce the resistance, it is necessary to make a combination that does not allow a loop current to flow. For example, when the number of poles of the coil is nine, when the coil pairs are connected in parallel, a coil having a phase shift is connected, and a disadvantage that a loop current flows there occurs. Therefore, in consideration of the above-mentioned matter, it is understood that the number of poles of the coil needs to be at least 12 coils. Further, as described above, the generation of the loop current is also prevented by connecting the coils wound in opposite directions in series to form a pair.

Further, when cogging is reduced by providing a skew angle, for example, it is assumed that the number of poles of the coil is 36 and the number of poles of the magnet is 48. At this time, each of the U-phase V-phase and the W-phase has 12 coils, but there is no phase difference between the 12 coils. Therefore, the effective magnetic field that contributes to the rotation of the motor only needs to consider the decrease in the magnetic flux due to the skew angle in the magnetic circuit of the coil and the magnet. Therefore, when the skew angle is provided, the effective magnetic flux is, for example, 5/6 (about 83%) as compared with when the skew angle is not provided.

On the other hand, in the motor 10 shown in FIG. 1, for example, when the coil 36 (iron core 34) has 36 poles and the magnet 23 has 30 poles, the coils of the U-phase, V-phase and W-phase have 12 coils.
And two sets of phase differences occur. Therefore,
The linkage magnetic field generated by each of the three phases is U / 2 = sin
(Θ-15) + sin (θ + 15), V / 2 = sin
((Θ-120) -15) + sin ((θ-120) +
15), W / 2 = sin ((θ−240) −15) + s
in ((θ−240) +15). For example, taking the U phase as an example, the above equation is U / 2 = 0.966 sin
θ, indicating that the effective magnetic field is about 97%.

As described above, the motor torque is about 83% when the skew angle is provided and the cogging countermeasure is performed, and the torque of the motor is about 9% as compared with the case where no cogging countermeasure is performed.
7%, which indicates that a higher torque can be obtained as compared with the related art. If there is no mechanical error, the cogging can be theoretically set to zero. On the other hand, when cogging is reduced by a combination of the number of iron cores 34 and the number of magnets 23, it cannot be set to zero. However, as long as the loss due to the shaft 11 and other factors are negligible in view of usability, the smaller the torque reduction, the better. Therefore, from the balance between torque and cogging, the number of poles of the iron core is 10 × n and the magnet 2
The number of poles of 3 was 12 × n (n is a natural number).

FIG. 7 is a graph showing the occurrence of cogging. FIG. 7A shows the height of the magnet 23 of 17 m.
FIG. 7B shows the occurrence of cogging when the height h of the salient pole portion 35b is set to 15 mm.
3 shows the occurrence of cogging when the height of No. 3 and the height h of the salient pole portion 34b are 15 mm. FIG. 7 shows that if the height of the magnet 23 is larger than the height h of the salient pole portion 34b, cogging increases. Therefore, by making the height of the magnet 23 and the height h of the salient pole portion 34b substantially the same, the occurrence of cogging can be suppressed.

According to the above-described embodiment, a high winding space factor can be achieved, so that a motor 10 with high efficiency and high torque can be realized. Also, because of low cogging, the motor 10
Vibration can be suppressed. Further, the stator core 3
Since the ring 33 and the iron core 34 are divided in 2,
It is possible to reduce the amount of material discarded during pressing,
The cost of the motor 10 can be reduced. In addition, since the coil 36 is arranged and wound, the weight-to-turn ratio is advantageous and the weight can be reduced.

The present invention is not limited to the above embodiment. For example, as shown in FIG.
May be formed so that the width d increases as the coil 36 wound around the coil 36 approaches the salient pole portion 35b. Specifically, the coil 36 at one end of the iron core 34
Coil 3 on the salient pole portion 34b side of the iron core 34 than the width d1 of
6 is wound so that the width d2 is larger. As a result, the coil space is enlarged, and higher torque can be obtained.

[0028]

As described above, according to the present invention,
A motor capable of reducing cogging and obtaining high torque can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a preferred embodiment of a motor according to the present invention.

FIG. 2 is a configuration diagram showing a rotor in the motor of the present invention.

FIG. 3 is a configuration diagram showing a stator core in the motor of the present invention.

FIG. 4 is a plan view showing a ring in the motor of the present invention.

FIG. 5 is a plan view showing an iron core in the motor of the present invention.

FIG. 6 is a plan view showing an insulator and a coil in the motor of the present invention.

FIG. 7 is a graph showing how cogging occurs in the motor of the present invention.

FIG. 8 is a configuration diagram showing a winding method of another coil in the motor of the present invention.

[Explanation of symbols]

10 ... motor, 11 ... shaft, 20 ... rotor,
21 ... rotor housing, 23 ... magnet,
30 ... stator, 31 ... stator housing,
33 ... ring, 34 ... iron core, 34b ... salient pole portion, 35 ... insulator, 36 ... coil.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shoji Tanana 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Toshiro Hayashi 6-7-1, Kita-Shinagawa, Shinagawa-ku, Tokyo No. 35 Sony Corporation F term (reference) 5H002 AA09 AC02 AC03 AC06 5H603 AA00 AA09 BB01 BB12 CA01 CA05 CB02 CC05 CC07 CD21 CE01 CE13 EE06 FA01

Claims (4)

[Claims] 1. A motor comprising a shaft, a stator fixed to the shaft, and a rotor arranged rotatably about the shaft with respect to the stator, wherein the rotor has a number of poles. The stator has a magnet formed so as to have a size of 10 × n (n is a natural number). The stator holds a ring fixed to the stator housing and an insulator around which a coil is wound. One end portion is fixed to the ring, the other end portion forms a salient pole portion, the salient pole portion has the magnet of the rotor and an iron core constituting a magnetic circuit, The number of poles of the iron core is 12 × n (n is a natural number)
A motor characterized by being arranged so that 2. The motor according to claim 1, wherein a height of the core salient pole portion is substantially equal to a height of the magnet. 3. The motor according to claim 1, wherein the width of the coil is formed so as to increase toward an outer peripheral surface. 4. The coil, wherein two adjacent coils are wound such that winding directions thereof are opposite to each other, and are electrically connected in series to form a coil pair. The motor according to claim 1, which is connected in parallel.