JPH11234989A - Smooth armature type three-phase brushless motor - Google Patents

Abstract

(57) [Problem] To provide a smooth armature type three-phase brushless motor which is easy to manufacture with high performance by improving short-section coefficient. SOLUTION: A rotor in which an even number of permanent magnets 2 are arranged on the surface of an iron core 4 at equal intervals so as to have mutually different polarities, a stator which is arranged via a gap so as to face the rotor, and In a smooth armature type three-phase brushless motor having a plurality of coils 1 of non-overlapping concentrated winding on a core 3, the number of coils 1 is 6 n and the number of poles is 10 n (n is a natural number). Therefore, it is possible to obtain a high-output smooth armature type three-phase brushless motor with an improved short interval coefficient.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless motor used in FA and OA, and more particularly to a brushless motor of a smooth armature type.

[0002]

2. Description of the Related Art A conventional three-phase, four-pole, six-coil brushless motor is configured as shown in FIG. In the drawing, six coils 11U, 11U ', and 11 for three phases are provided on the inner diameter side of a stator core 10 in which ferromagnetic thin plates are stacked.
V, 11V'11W, 11W 'are connected to a series and concentratedly mounted. On the surface of the rotor core 12,
Four rare-earth permanent magnets 13 are alternately stuck at equal circumferential pitches so that adjacent poles have different polarities to form a rotor magnetic pole. Reference numeral 14 denotes a rotating shaft which is mounted on a bracket fixed to a frame (not shown) via a bearing. The operation of the thus configured brushless motor will be described. The coils 11u, 11u ', 11v, 11v', 11w,
11w ', the permanent magnet 13 attached to the rotor
The rotor rotates due to the electromagnetic action.

[0003]

However, the thickness of the stator yoke is proportional to the magnetic flux density of the gap and the pole pitch. D
When g is the gap diameter and P is the number of poles, the pole pitch = Dg /
It becomes P. Assuming that the gap density Bg is constant, the yoke can be made thinner as the number of poles P increases, so that the motor becomes smaller. However, when the number of poles is increased, the number of coils is also increased, which leads to a decrease in productivity. Therefore, a fractional slot winding of non-overlapping concentrated winding is used. Conventional 4-pole, 6
The example of the coil is also a fractional slot winding in which the number of slots q per pole and phase is １ ／. If q = 1/5, 10 poles can be constituted by 6 coils. However, in the case of non-overlapping concentrated winding, the short section coefficient is as low as 0.5 and the efficiency is reduced. Therefore,
SUMMARY OF THE INVENTION An object of the present invention is to provide a high-performance smooth armature brushless motor by improving the short-circuit coefficient.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a rotor having an even number of permanent magnets arranged at equal intervals on the surface of an iron core so as to have mutually different polarities, and a rotor facing the rotor. In a smooth armature type three-phase brushless motor including a stator arranged via a gap so as to form a plurality of coils of non-overlapping concentrated winding on the stator core, the number of coils is 6n, and the number of poles is 6 10n (n is a natural number).

[0005]

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 front sectional view of a smooth armature type three-phase brushless motor according to an embodiment of the present invention. In the figure, reference numeral 1 denotes a coil which is fixed to the inner surface of a cylindrical stator core 3 with an impregnated resin or the like. The number of the coils 1 is six, and as shown in the figure, U, U ', W, W', V, V '
A phase coil 1 is arranged. Reference numeral 2 denotes a permanent magnet, which is fixed to the outer periphery of the iron core 4 so that adjacent permanent magnets 2 have opposite polarities. Although the surface of the permanent magnet 2 facing the coil 1 is formed in an arc shape, it may be formed in a sine wave shape to smooth the magnetic flux change to reduce the harmonic component of the induced voltage waveform. The magnet 2 may be multipolar magnetized on a ring-shaped magnet to reduce the number of manufacturing steps. Ten permanent magnets 2 are arranged on the outer periphery of the iron core 4. A shaft 5 is arranged on the inner periphery of the armature core 4 so as to be integral with the armature core 4. The shaft 5 is rotatably supported by a bearing (not shown). FIG. 2 schematically shows the coil 1 shown in FIG. Mutual coil 1
Are arranged at a predetermined coil pitch. The coil 1 has a concentrated winding, and a coil inner width W1 is provided inside the coil 1. The coil 1 is manufactured by winding into a winding form having a predetermined inner width W1. Although a round wire or a flat wire is used for the coil 1, the motor characteristics can be improved by using a flat wire because the space factor can be increased. Next, the winding coefficient of the smooth armature type three-phase brushless motor of the present invention will be described. The winding coefficient is composed of a distribution coefficient, a short-term coefficient, a skew coefficient, and the like. The short term coefficient kp of the slot winding type motor is expressed by the following equation. kp = sin (βπ / 2) (kp ≦ 1) β = P / N (X # -1) P: Number of poles N: Number of slots X #: Jump of coil β indicates the jump of the coil with respect to the magnetic pole pitch. The closer to, the higher the fundamental component of the short-term coefficient. 6 slots, 1
In the case of 0 poles and concentrated winding, β = 10/6 (2-1) = 1.6
At 6 °, the value is larger than 1. In this case, the short-term coefficient is 0.5 from the above equation, which is half of the maximum value 1. The coil jump of the slot winding of the smoothing armature is replaced by the coil jump equivalent dimension H shown in FIG. The coil jump equivalent dimension H is represented by the sum of the coil width W and the coil inner width W1, and is smaller than the coil pitch A.
By setting 1 appropriately, β can be brought close to 1. For example, the larger the coil inner width, the larger the coil jump equivalent dimension H, and the smaller the coil inner width W1, the smaller the coil jump equivalent dimension H. As a result of the experiment, it was found that the coil inner width should be set to 0.05 to 0.3 with respect to the coil pitch. Next, the operation of the brushless motor with smooth armature will be described. When a predetermined current is applied to the coil by magnetic pole detection means (not shown), the rotor composed of the permanent magnet 2, the iron core 4, the shaft 5, etc. Rotate. Since the short bar coefficient is improved, the rotation performance is improved. In the embodiment, the inner rotor in which the arc-shaped permanent magnet is adhered to the outer peripheral surface of the iron core 4 of the cylindrical soft magnetic material is described. Further, in the embodiment, a three-phase, six-coil, ten-pole motor has been described in order to obtain an efficient motor with a small number of slots. Therefore, even if a 40-pole motor is manufactured, only 24 coils are required. Further, in the embodiment, the rotary type motor has been described,
Also applicable to linear motors.

[0006]

As described above, according to the present invention, it is possible to obtain a high-performance smooth armature type three-phase brushless motor with improved short interval coefficient.

[Brief description of the drawings]

FIG. 1 is a front sectional view of a smooth armature type three-phase brushless motor according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a coil of a smooth armature type three-phase brushless motor of the present invention.

FIG. 3 is a front sectional view of a smooth armature type three-phase brushless motor according to the related art.

[Explanation of symbols]

1 coil, 2 permanent magnet, 3 stator core, 4
Armature core, 5 shafts

Claims (5)

[Claims] A rotor having an even number of permanent magnets arranged on the surface of an iron core at equal intervals so as to have mutually different polarities; a stator arranged via a gap so as to face the rotor; A smoothing armature type three-phase brushless motor comprising a stator core and a plurality of non-overlapping concentrated winding coils, wherein the number of coils is 6n and the number of poles is 10n (n is a natural number). Child type three-phase brushless motor. 2. A three-phase brushless motor according to claim 1, wherein the surface of the permanent magnet facing the coil is a sine-wave permanent magnet. 3. The brushless motor according to claim 1, wherein the permanent magnet is formed as a multi-pole magnetized ring. 4. The brushless motor according to claim 1, wherein an inner width of the coil is set to 0.05 to 0.3 with respect to a coil pitch. 5. The brushless motor according to claim 1, wherein the coil is formed of a rectangular winding.