JPH10155262A - Magnet type brushless motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnet type brushless motor, which can be used at a high rotational speed close to 3 times compared to the conventional one with a high conversion efficiency and a high torque and also can be used as a drive motor for car. SOLUTION: In a motor comprising a stator 1 having a plurality of stator magnetic pole 11 and field winding 12, a rotor 2 having a rotating shaft 21 and a field magnet 3, and a control circuit supplying a current to the field winding 12 by detecting a position for a stator 1 of a magnetic pole of field magnet 3, the field magnet 3 being fixed to a rotating shaft 2 and comprising a first field magnet where the magnetic poles with the different polarities sequentially arranged in the rotating direction and a second field magnet where the magnetic poles with different polarities sequentially arranged in the rotating direction in a rotatable manner relative to the first field magnet, and the phase relative to the first field magnet of the magnetic poles made by synthesizing the first and second field magnets being changed in response to the rotation of the rotor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnet type brushless motor useful as a motor using a permanent magnet as a field (for example, for a power source of an electric vehicle).

[0002]

2. Description of the Related Art In an internal combustion engine of an automobile or the like, a rotation region for generating a high torque is very narrow. Therefore, as shown in FIG. 6, a transmission composed of several types of gears having different gear ratios is used so that the vehicle can run at an arbitrary speed from a low speed to a high speed.

However, as shown in FIG. 7, the relationship between the rotational speed and the torque of a conventional Briless DC motor using a permanent magnet is such that the torque decreases linearly with the rotational speed in inverse proportion to the rotational speed. . Assuming that the voltage applied to the motor is V, the total magnetic flux obtained by multiplying the strength of the magnetic field created by the field of the motor by the effective area of the field is Φ, the number of windings of the armature is Z, and the resistance is R,
The maximum value (n _max ) of the rotation speed is V / ΦZ, and the maximum value (T _max ) of the torque is ΦZV / R. When the voltage V is doubled, the maximum torque and the maximum rotation speed are both doubled. By changing the number of windings Z, the maximum torque and the maximum rotation speed can be changed. The torque increases as the total magnetic flux Φ increases, but it is necessary to determine the upper limit value while paying attention to magnetic saturation on the armature side.

However, in the conventional brushless DC motor, a high torque can be obtained in a low-speed rotation range, but it is difficult to rotate at a high speed because the variable range of the rotation speed is narrow.
Therefore, the maximum value (n _max ) of the number of rotations is reduced by lowering the total magnetic flux Φ at the time of high-speed rotation by a method called “weak magnetic field”.
May be raised. When the rotational speed is low, the torque shown by the solid line in FIG. 7 is obtained with a large total magnetic flux Φ, and when the rotational speed is high, the total magnetic flux Φ is reduced to obtain the characteristic shown by the broken line in FIG. Thus, it is conceivable to rotate to a higher rotation speed.

It has also been proposed to change the total magnetic flux with the number of revolutions in the case of a generator. JP-A-7-2362
No. 59 "Permanent Magnet Generator" includes a permanent magnet generator which generates an electromotive force in the stator by interlinkage magnetic fluxes from a plurality of poles of the field permanent magnet used in the rotor. A permanent magnet for magnetic flux bypass having the same number of poles as the field permanent magnet and rotatably disposed coaxially on its side in proximity to the permanent magnet, and a governor mechanism displaced according to the rotation speed of the rotor; The permanent magnet for magnetic flux bypass can be rotated by a half cycle of the magnetic polarity in response to the displacement of the governor mechanism, and when the rotor is stopped, the magnetic polarity of the permanent magnet for bypass is changed to the magnetic field for the field. There is disclosed an arrangement in which the permanent magnets are arranged to have the same polarity as the permanent magnets, and the governor mechanism rotates the bypass permanent magnets to a position having a polarity opposite to that of the field permanent magnets in a high-speed region. In this way, at low speed rotation, the linkage flux from the magnetic pole of the field permanent magnet is increased,
During high-speed rotation, the linkage magnetic flux from the field permanent magnet is weakened to keep the generated power constant.

[0006]

However, the field weakening control method always monitors the torque, the rotational speed, and sometimes the rotational acceleration, and performs a complicated calculation based on those numerical values to determine the magnitude and phase of the current. Must be controlled, requiring complex and expensive control circuits, including high-speed computers. Also, in the conventional magnet type brushless DC motor, it has been found that even if an attempt is made to reduce the amount of interlinkage magnetic flux by shorting the magnetic poles on the side of the field permanent magnet as in the above-described conventional generator, it cannot be sufficiently reduced. did. That is, as is apparent from the equation of the maximum value of the rotation speed n _max = V / ΦZ, the means for increasing n _max (also called the no-load rotation speed) by a factor of two or more is based on a simple decrease in the total magnetic flux Φ. Need to be reduced by 50% or more, but the present inventors have confirmed that short-circuiting the side surfaces of the field magnet only reduces at most less than about 20 to 30%. Further, in the above-described conventional generator, since the permanent magnet for magnetic flux bypass is outside the closed magnetic circuit formed by the rotor and the stator of the generator, if it hardly contributes to the output of the generator, When there is a conductive and / or magnetic structure such as a motor case near the permanent magnet for magnetic flux bypass, an eddy current is generated inside the motor case by the magnetic flux generated by the permanent magnet for bypass. It is conceivable that the conversion efficiency of the electric motor is reduced due to the attraction force with the magnetic material. Further, since the permanent magnet for bypass is an additional component, there is a drawback that the generator is easily increased in size.

Therefore, according to the present invention, when the rotational speed is low, a high torque can be obtained in the same manner as the conventional one, and at the same time, the torque can be used with a high torque up to three times higher than the conventional one with high conversion efficiency. It is an object to provide a magnet type brushless electric motor (for example, for driving an automobile).

[0008]

According to the present invention, there is provided a magnet type brushless electric motor having a plurality of stator magnetic poles, a stator having a winding for generating a rotating magnetic field in the stator magnetic pole, a rotating shaft, and a rotating shaft. A rotor having a field magnet provided on a rotating shaft and rotating with respect to the plurality of stator magnetic poles;
And a magnet type brushless motor having a control circuit for detecting a position of a magnetic pole of the field magnet with respect to the stator and supplying a current to the winding according to the position, wherein the field magnet rotates. A first field magnet in which magnetic poles of different polarities are sequentially arranged in a direction, and a second field magnet in which magnetic poles of different polarities are sequentially arranged in a rotational direction relative to the first field magnet. And the first and second field magnets face the stator magnetic poles, and
It has a mechanism for changing the phase of the combined magnetic pole of the first and second field magnets with respect to the magnetic pole of the first field magnet as the rotor rotates. .

The mechanism for changing the phase of the combined magnetic poles of the first and second field magnets with respect to the magnetic poles of the first field magnet with rotation of the rotor is as follows. When the rotation speed is low, the first and second field magnets are preferably arranged such that magnetic poles of the same polarity are arranged, and when the rotation speed is high, the magnetic poles are deviated therefrom.

Further, the phase of the combined magnetic pole of the first and second field magnets is shifted in the direction of rotation of the rotor with respect to the magnetic pole of the first field magnet, thereby causing a change in the rotational speed. It is preferable that the advance angle changes in accordance with.

The mechanism for changing the phase of the combined magnetic pole of the first and second field magnets with respect to the magnetic pole of the first field magnet with the rotation of the rotor is the centrifugal force of the rotor. It is preferable to use.

Further, the present invention provides a stator having a plurality of stator magnetic poles and a winding for generating a rotating magnetic field on the stator magnetic pole, a rotating shaft and the plurality of stators provided on the rotating shaft. A rotor having a field magnet rotating with respect to the magnetic pole, and a control circuit for detecting a position of the magnetic pole of the field magnet with respect to the stator and supplying a current to the winding according to the position. In the magnet type brushless electric motor, the field magnet is rotatable relative to a first field magnet in which magnetic poles of different polarities are sequentially arranged in a rotating direction and the first field magnet. A second field magnet in which magnetic poles of different polarities are sequentially arranged in the rotation direction, wherein the first and second field magnets face the stator pole and The phase of the combined magnetic pole of the first and second field magnets is The mechanism for changing the magnetic pole of the rotor with rotation of the rotor utilizes centrifugal force of the rotor. When the rotation speed of the rotor is low, the first and second field magnets have the same polarity. Are arranged so that the magnetic poles deviate therefrom when the rotation speed is high.

Further, the present invention provides a stator having a plurality of stator magnetic poles and a winding for generating a rotating magnetic field in the stator magnetic poles, a rotating shaft and a plurality of stators provided on the rotating shaft. A rotor having a field magnet rotating with respect to the magnetic pole, and a control circuit for detecting a position of the magnetic pole of the field magnet with respect to the stator and supplying a current to the winding according to the position. In the magnet type brushless electric motor, the field magnet is rotatable relative to a first field magnet in which magnetic poles of different polarities are sequentially arranged in a rotating direction and the first field magnet. A second field magnet in which magnetic poles of different polarities are sequentially arranged in the rotation direction, wherein the first and second field magnets face the stator pole and The phase of the combined magnetic pole of the first and second field magnets is The mechanism for changing the magnetic pole of the rotor with rotation of the rotor utilizes centrifugal force of the rotor. When the rotation speed of the rotor is low, the first and second field magnets have the same polarity. Are arranged so that the magnetic poles deviate therefrom when the rotation speed is high, and the phase of the combined magnetic pole of the first and second field magnets rotates with respect to the magnetic pole of the first field magnet. A magnet type brushless electric motor characterized in that an advance angle changes with a change in the number of rotations by shifting in the rotation direction of the child.

Further, the present invention provides a stator having a plurality of stator magnetic poles and a winding for generating a rotating magnetic field on the stator magnetic pole, a rotating shaft and a plurality of stators provided on the rotating shaft. A rotor having a field magnet rotating with respect to the magnetic pole, and a control circuit for detecting a position of the magnetic pole of the field magnet with respect to the stator and supplying a current to the winding according to the position. In the magnet type brushless electric motor, the field magnet is rotatable relative to a first field magnet in which magnetic poles of different polarities are sequentially arranged in a rotating direction and the first field magnet. A second field magnet in which magnetic poles of different polarities are sequentially arranged in the rotation direction, wherein the first and second field magnets face the stator pole and The phase of the combined magnetic pole of the first and second field magnets is The mechanism that changes with the rotation of the rotor with respect to the magnetic pole of the rotor is such that the movable side shaft of the governor connected by an elastic member along the hole of the fixed member fixed to the rotation shaft moves in the forward or reverse direction of the rotor rotation A magnet type brushless electric motor characterized in that the magnet type brushless electric motor is configured by moving and applying a relative rotational force to a second field magnet from a movable side shaft thereof.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. FIG. 1 is a perspective view of an exploded main part of a magnet type brushless DC motor according to one embodiment of the present invention. In FIG. 1A, a field winding 12 for generating a rotating magnetic field around a plurality of (12 poles in this figure) stator magnetic poles 11 is wound around the stator 1. The rotor 2 includes a rotating shaft 21 and the field magnet 3.
To indicate the position of the magnetic pole of the field magnet 3,
1 and a sensor magnet 22 (for example, a ferrite-based plastic magnet or the like) that forms a magnetic pole pattern having the same central angle as the field magnet 3 in the rotation direction of the outer peripheral surface thereof. I have. The field magnet 3 is the rotating shaft 2
The first field magnet 31 fixed around the ferromagnetic rotor core 7 via the ferromagnetic rotor core 7 and the first field magnet 31 so as to be rotatable relative to the first field magnet 31 And a second field magnet 32 fixedly mounted on the second magnetic field. The first and second field magnets 31 and 32 are both ring-shaped Nd-Fe-B magnets of the same dimensions (e.g., eight different magnetic poles 4 formed alternately at equal intervals in the rotation direction of the outer peripheral surface). Anisotropic sintered magnet manufactured by Hitachi Metals, Ltd .: HS40AH, etc.). A position of an arbitrary magnetic pole of the field magnet 3 with respect to the stator 1 is indicated by a sensor magnet 22, and a control circuit (not shown) for switching a current supplied to the field winding 12 according to the position of the magnetic pole is provided. Thus, a predetermined rotating magnetic field is generated in the stator magnetic pole 11. As shown, the first,
The second field magnets 31 and 32 are arranged opposite to the stator magnetic poles 11 with a narrow air gap 6 therebetween to constitute a magnet type brushless motor 50 of the present invention. With this configuration, the magnetic fluxes emitted from the first and second field magnets 31 and 32 are both efficiently guided to the stator magnetic poles 11 and interlink with the field windings 12, so that the surrounding magnetic structures are not affected. It is possible to avoid the problem that the leakage magnetic flux passing therethrough is suppressed to a small value and a loss such as an eddy current loss occurs in a surrounding structure.

FIG. 1B shows that the second field magnet 32 is rotated relative to the first field magnet 31 in the direction of rotation of the rotor 2 so that the positions of the two magnetic poles are shifted. State. The phase of the magnetic pole obtained by combining the first and second field magnets 31 and 32 with respect to the magnetic pole of the first field magnet 31 changes as the rotor 2 rotates. The energization of the field winding 12 is controlled by detecting the magnetic pole of the sensor magnet 22 by detecting means (not shown) such as a Hall element. In the case of a brushless DC motor, the center of the conduction period of the winding for generating a rotating magnetic field is theoretically the N of the magnetic pole for the field.
The maximum torque can be obtained by matching the S switching point. However, in anticipation of a delay in the rise of the current with respect to the energization command signal due to the inductance of the winding for generating the rotating magnetic field, it is widely practiced to move the center of the energization period forward in the rotation direction from the NS switching point of the field magnetic pole. Yes,
The angle at which this energization period is advanced is generally called an advance angle. In the present invention, setting of this advance angle is also important.

FIGS. 2A and 2B show the sensor magnet 2.
The positional relationship between the second magnetic pole and the magnetic poles of the first field magnet 31 and the second field magnet 32 is shown. 1 (A) and 2
(A) shows a first field magnet 31 and a second field magnet 3.
2, since the same magnetic poles are adjacent to each other, the phase of the combined magnetic pole of the first and second field magnets 31 and 32 (for example, the center of the combined magnetic pole) is the sensor magnet 22 and the first field. 1B (for example, the center of the magnetic pole), but in FIG. 1 (B) and FIG. 2 (B), the second The state where the magnet 32 is shifted in the rotation forward direction is shown. Here, the first field magnet 31 and the second field magnet 32 generate exactly the same amount of magnetic flux, and the second field magnet 32 is connected to the first field magnet 31. On the other hand, when the magnetic poles are shifted in the forward direction (a degrees), the phases of the combined magnetic poles of the first and second field magnets 31 and 32 become the magnetic poles of the first and second field magnets 31 and 32. It becomes the average value of the phase, and the phase of the synthesized magnetic pole (for example,
The center of the composite magnetic pole. ) Leads the phase of the magnetic pole of the first field magnet 31 (for example, the center of the magnetic pole) by an advance angle (a / 2 degrees) in the rotation forward direction.

Then, the first and second field magnets 31, 3
When the rotation speed of the rotor 2 is low, the mechanism of changing the phase of the combined magnetic poles of the first and second field magnets with respect to the first field magnet 31 with the rotation of the rotor 2 is shown in FIGS. In this way, the same magnetic poles of the first and second field magnets 31 and 32 are arranged side by side, and when the rotation speed is high, both magnetic poles are shifted to be as shown in FIG. 1 (B) or FIG. 2 (B). It is desirable. That is, when the magnetic poles are shifted, any S pole of the first field magnet 31 and any N pole of the second field magnet 32
The pole, an arbitrary N pole of the first field magnet 31 and an arbitrary S pole of the second field magnet 32 partially overlap when viewed from the longitudinal direction of the rotating shaft 21. . As described above, a local short circuit of the generated magnetic flux occurs in a portion where the opposite magnetic poles are adjacent to each other, so that the amount of interlinkage magnetic flux reaching the field winding 12 on the stator 1 side is reduced. . That is,
When the rotational speed is high, the amount of interlinkage magnetic flux is reduced in accordance with the relative magnetic pole shift between the two, and when the rotational speed is low, the magnetic poles of the first and second field magnets 31, 32 are reduced. Are arranged around the rotation axis 21 to maximize the amount of interlinkage magnetic flux. Since the magnet type brushless motor 50 of the present invention has the above-described configuration, it is possible to control the amount of interlinkage magnetic flux in accordance with a wide range of rotation speed change.

In FIG. 1, the magnetic pole phases of the first field magnet 31 and the sensor magnet 22 are fixed, and the second field magnet 3
2 is rotatable relative to the first field magnet 31, and the magnetic pole of the second field magnet 32 is rotated with respect to the magnetic pole of the first field magnet 31 during high-speed rotation. Are relatively displaced in the forward rotation direction. In the present invention, the combination of whether the three members of the field magnets 31 and 32 and the sensor magnet 22 are fixed or rotatable is optional. For example, the magnetic pole phases of the second field magnet 32 and the sensor magnet 22 are optional. May be fixed and the magnetic pole of the second field magnet 32 may be relatively displaced in the forward rotation direction with respect to the magnetic pole of the first field magnet 31 during high-speed rotation.
In addition, the magnetic pole phases of the second field magnet 32 and the sensor magnet 22 are fixed, and the magnetic pole of the second field magnet 32 is higher than the magnetic pole of the first field magnet 31 during high-speed rotation. The rotation may be relatively shifted in the reverse direction. Further, the magnetic pole phases of the first field magnet 31 and the sensor magnet 22 are fixed, and the magnetic pole of the second field magnet 32 is higher than the magnetic pole of the first field magnet 31 during high-speed rotation. The rotation may be relatively shifted in the reverse direction. Further, as an example in which the first field magnet 31 and the second field magnet 32 are arranged so that the generated magnetic flux amounts are different from each other, for example, in the state of FIG. When the ratio of the amount of interlinkage magnetic flux of the second field magnet 32 is 1: 2,
The change ratio of the amount of magnetic flux linked to the field winding 12 can be increased by the same magnetic pole shift operation as compared with the case where the ratio is 1: 1. Further, by providing a separate phase changing mechanism for the sensor magnet 22, the advance angle can be changed independently of the rotation speed at the time of low rotation and high rotation, and substantially at the time of low rotation and high rotation. It is also possible to adopt a configuration in which the advance angle does not change.

A mechanism for changing the phase of the combined magnetic pole of the first and second field magnets 31 and 32 with respect to the magnetic pole of the first field magnet 31 with the rotation of the rotor 2 is shown in FIG. Are preferred. In FIG. 3, the first field magnet 3
1 is fixed to the rotating shaft 21 and a second field magnet 32
The rotary shaft 21 is inserted through the central shaft hole 321 so as to rotate around the rotary shaft 21 by a predetermined amount. An interval of several mm 5 between the first field magnet 31 and the second field magnet 32 so that the magnetic pole shift operation is not hindered by the attraction and / or repulsion acting between the two. It is desirable to keep open. The governor fixing plate 33 is connected to the rotating shaft 21.
And the end faces of the governor fixing plate 33 are provided at symmetric positions in the vertical and horizontal directions at a central angle of 90 degrees.
The rotation shaft 341 is fitted in each of the three holes 331.
The governor 34 is a substantially arc-shaped part and has through holes 348 at both ends.
349 are provided. The rotation support shaft 341 is provided in the through hole 348.
The movable side shaft 342 is fitted in the through hole 349 to hold the governor 34. Further, the hole 33
Four arc-shaped long holes 332 are provided near each of the points 1 in a point-symmetric manner. On one end surface of the rotor core 8, four long grooves 322 are provided in the radial direction symmetrical in the vertical and horizontal directions at a central angle of 90 degrees, and the movable side shaft 342 is inserted into each of the long holes and each of the long grooves. At the same time, the four movable shafts 342 are connected to each other by a spring 343 so as to be attracted by their elastic force. When the rotation speed of the rotor 2 is low due to the tension of the spring 343, the movable side shaft 342 of the governor 34 is located closest to the rotation shaft 21 in the elongated hole 332 as shown in FIG. In this case, the same magnetic poles of the second field magnet 32 and the first field magnet 31 are arranged side by side. When the rotation speed of the rotor 2 increases, the governor 34 opens to the state shown in FIG. 3B due to centrifugal force, and the movable side shaft 342 of the governor 34 extends along the elongated hole 332 of the governor fixing plate 33 on the outer peripheral side. At the same time as the long groove 322
Is provided in the rotation direction toward the outer peripheral side of the rotor 2 with respect to the long hole 332, so that the insertion portion of the long groove 322 of the shaft 342 on the movable side is inserted through the long groove 322 to the rotor core 8.
Is rotated in the direction of the arrow, so that the second field magnet 32 can rotate in the direction of the arrow with respect to the first field magnet 31. Since the centrifugal force decreases when the rotation speed of the rotor 2 decreases, the governor 34 is moved by the tension of the spring 343 as shown in FIG.
(A), the first and second field magnets 31 and 3 are closed.
The position returns to the position where the same magnetic poles are arranged. As described above, the mechanism for rotating the second field magnet 32 relative to the first field magnet 31 by a predetermined amount around the rotation shaft 21 does not require external control and power. Since the operation is performed only by the centrifugal force acting on the components, the linkage flux amount of the magnet type brushless motor can be easily and inexpensively controlled with a simple mechanism. Further, as described above, the rotor core 8 has the long groove 32.
2, the axial dimension (L) extending from the long groove 322 to the governor 34 can be suppressed from increasing, and the above-described magnetic pole shift operation occurs at a predetermined rotation speed in consideration of the acting centrifugal force. By appropriately setting the spring constant of the spring 343 as described above, a high torque and a high motor exchange efficiency can be obtained in a wide rotation speed region as shown in an embodiment described later.

(Embodiments A to D) In the magnet type brushless motor 50 of the present invention, Nd-Fe-B manufactured by Hitachi Metals, Ltd. is used as the first and second field magnets 31, 32.
The above magnetic pole shift mechanism accompanying an increase in the number of revolutions under the condition that a radial anisotropic ring magnet (HS-30BR, outer diameter 74 mm, shaft length 23 mm) is used and the thickness of the air gap 6 is 0.5 mm. FIG. 4 shows the rotation speed-torque characteristics and FIG. 5 shows the rotation speed-motor conversion efficiency when the effective reduction amount of one tooth and the lead angle are simultaneously changed under the conditions shown in Table 1 below. Here, the single tooth effective magnetic flux means the maximum interlinkage magnetic flux that flows from the magnet rotor to one magnetic pole of the armature. (Conventional example e) The first and second field magnets are the same as those of the above embodiment, but the second field magnet is also arranged so that the same magnetic poles as the first field magnet are arranged. Rotational speed of a conventional magnet type brushless motor evaluated in the same manner as in the above embodiment except that it was fixed to the rotating shaft and the lead angle was fixed at 5.5 degrees.
FIG. 4 shows the torque characteristics, and FIG. 5 shows the rotation speed-motor conversion efficiency.

[0022]

[Table 1]

Referring to FIGS. 4 and 5 and Table 1 as a representative of the magnet type brushless motor of the embodiment A,
When the rotation speed is less than rpm, the advance angle at low rotation is 20
The rotation angle is set so as to be higher than 1000 rpm, and when the magnetic pole shift is 28 degrees (maximum value), the advanced angle at high rotation is set to 6 degrees. That is, when the rotation speed is less than 1000 rpm, the sensor advance angle is set to 20 degrees in a state where the magnetic poles of the first and second field magnets 31 and 32 are aligned without phase shift. When the rotation speed becomes 1000 rpm or more, the second field magnet 32 rotates 28 degrees with respect to the first field magnet 31 in the rotation direction of the rotor 2 by the action of the governor 34 due to the centrifugal force. Then, the phase of the combined magnetic pole of the first and second field magnets 31 and 32 advances by half the phase of the magnetic pole of the second field magnet 32. Therefore, the advance angle is delayed accordingly. When the magnetic pole deviation of the second field magnet 32 reaches the maximum of 28 degrees, the advance angle is delayed by 14 degrees, which is half of that, to 6 degrees. At this time, the reduction rate of the effective magnetic flux of one tooth is 34% (100% → 66).
%), And it was found that higher torque and higher motor exchange efficiency could be obtained in a wider rotational speed range than the conventional example E. In addition, Examples B, C, and D also show
It was found that higher torque and higher motor exchange efficiency could be obtained in a wider rotation speed range than the conventional example E. Further, comparing Examples A, B, C, and D, it was found that the larger the advance angle at low rotation, the higher the torque and motor exchange efficiency in a wider rotation speed range.

As is clear from FIGS. 4 and 5, the magnet type brushless motor of the present invention has no load rotation speed without lowering the rated torque (7 Nm) and the maximum efficiency as compared with the motor of the conventional specification. (N _max ) could be increased to 2.8 times. In addition, high torque and motor exchange efficiency were obtained in a wide rotation speed range.

The magnitude of the magnetic pole shift angle (θ: degree) is determined by calculating the central angle of each magnetic pole of the n poles when a symmetrical n pole magnetic pole pattern is formed on the outer peripheral side of the field magnets 31 and 32. When (x: degree), it is preferable that x / 2 ≦ θ ≦ 0.8x. This is because if it is less than (x / 2: degree), it is difficult to secure a reduction rate of the effective magnetic flux of one tooth of 30% or more due to the magnetic pole shift operation accompanying an increase in the number of revolutions, and (0.8x:
This is because, if it exceeds (degree), there is a high possibility that a rotational force in the opposite direction will be generated, which will hinder the magnetic pole displacement mechanism of the present invention. It is preferable that the lead angle (α: degree) is 0 <α ≦ x / 2. This is because the upper limit value is obvious from the definition of the lead angle, and the lower limit value can be set to a controllable lead angle that does not include 0.

Next, in the above-mentioned magnet type brushless motor 50, the same magnets as the first and second embodiments are used as the first and second field magnets 31 and 32. FIG. 8 shows the rotational speed-torque characteristics and FIG. 9 shows the rotational speed-motor conversion efficiency when the magnetic pole is shifted while the advance angle is fixed as shown in Table 2 below under the condition of the air gap thickness. For comparison, the results of the above-described conventional example E are also shown in FIGS.

[0027]

[Table 2]

FIGS. 8 and 9 show an embodiment in which the lead angle is fixed and the magnetic pole of the second field magnet 32 is shifted by 28 degrees with respect to the magnetic pole of the first field magnet 31. It was also found that a higher torque and higher motor exchange efficiency could be obtained in a wider rotational speed range than in the conventional example E. Further, from the comparison of Examples, it was found that the larger the advance angle, the higher the torque and the motor exchange efficiency can be obtained in a wide rotational speed range.

Even when the advance angle is fixed, it is preferable that the magnetic pole shift angle (θ: degree) is set to x / 2 ≦ θ ≦ 0.8x in the same manner as described above. For the advance angle (α: degree), 0 <
It is preferable that α ≦ x / 2.

In the above embodiment, the example was described in which the effective magnetic flux per tooth was reduced by 34% by the simultaneous variation of the magnetic pole shift operation and the advance angle, or the magnetic pole shift operation alone. It is very easy to reduce the amount by 30% or more. More preferably, the reduction rate is 4
It can be 0% or more, particularly preferably 50%. Further, in the above aspect of the present invention, the case where the same symmetrical 8-pole magnetic pole pattern is formed on the outer peripheral surface of the first and second field permanent magnets has been described, but both are the same asymmetric magnetic pole pattern. Is also good. Further, the number of magnetic poles is not limited, but is preferably 2 to 128, more preferably 4
Very useful for ~ 32 poles. Further, the first and second field magnets may have different magnetic pole patterns. Furthermore, for example, by setting the ratio of the amount of interlinkage magnetic flux generated in a state where the same magnetic poles of the first and second field magnets are lined up to different appropriate values, the rotation speed is increased and one magnetic pole is increased. A larger change in the amount of interlinkage magnetic flux can be achieved by the shift operation. Further, in the above aspect of the present invention, the amount of interlinkage magnetic flux of the magnet type brushless motor is reduced by using the two field magnets arranged coaxially and rotating one of them relative to the rotation speed. However, the present invention is also configured by fixing one or two or more field magnets to the rotating shaft using three or more field magnets and relatively rotating the remaining field magnets. be able to. In the present invention, the shape, size, number, etc. of the field magnets are not limited, and any field may be formed on the rotor core so that different magnetic poles are formed alternately in the rotation direction of the outer peripheral surface of the rotor. A magnet for magnet can be arranged. For example, the arc segment magnets may be continuously adhered in a ring shape in the direction of rotation of the outer peripheral surface of the rotor core opposed to the stator, or at predetermined intervals in the direction of rotation of the outer peripheral surface of the rotor core. The rotor 2 may be substituted by a configuration or the like in which arc segment magnets are arranged for a predetermined number of magnetic poles. Further, a thin cover (for example, a non-magnetic cover or the like) may be disposed on the outer peripheral surface of the field magnet shown in FIG. Further, in the above-described embodiment of the present invention, the configuration in which the movable side shaft of the governor is connected by a spring is described, but various known springs may be used as the spring. Further, various known rubbers may be used instead of the spring, or a spring and a rubber may be used in combination.

[0031]

As described above, the magnet-type brushless motor of the present invention can obtain a high torque at a low rotation speed as in the conventional motor, and is nearly three times as high as the conventional motor. Since the motor can be used at high torque up to the rotation speed and with high exchange efficiency, it has become useful, for example, as a motor for driving an automobile in place of an internal combustion engine.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a main part showing one embodiment of a magnetic brushless electric motor of the present invention, showing a state in which there is no magnetic pole shift (A) and a magnetic pole shift state (B).

FIG. 2 is a view for explaining the advance of the magnetic pole of the field magnet in the magnet type brushless motor of the present invention, showing a state where there is no magnetic pole shift (A) and a magnetic pole shift state (B).

FIG. 3 In the magnet type brushless motor of the present invention, the phase of the combined magnetic pole of the first and second field magnets is changed with the rotation of the rotor with respect to the magnetic pole of the first field magnet. It is an exploded perspective view which shows a mechanism, (A) is at the time of low rotation speed, (B) is at the time of high rotation speed.

FIG. 4 is a diagram showing an example of the rotation speed-torque characteristics of the present invention and a conventional magnet type brushless motor.

FIG. 5 is a diagram showing an example of the rotational speed-motor conversion efficiency of the present invention and a conventional magnet type brushless motor.

FIG. 6 is an output characteristic diagram of an internal combustion engine with a transmission.

FIG. 7 is a characteristic diagram of a conventional brushless DC motor.

FIG. 8 is a diagram showing another example of the rotation speed-torque characteristic of the magnet type brushless electric motor of the present invention.

FIG. 9 is a diagram showing another example of the rotational speed-motor conversion efficiency of the magnet type brushless electric motor of the present invention.

[Explanation of symbols]

1 stator, 2 rotors, 3 field magnets, 4 magnetic poles,
5 spacing, 6 air gap, 7, 8 rotor core, 11 stator magnetic pole, 12 field winding, 21 rotation axis, 22 sensor magnet, 31 first field magnet, 32 second field magnet , 33 fixing member, 34 governor, 50 magnet brushless motor, 321 shaft hole, 322 long groove, 331
Hole, 332 Slot, 341 Rotating support shaft (fixed shaft), 3
42 movable shaft, 343 elastic member, 348, 349 through hole.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masahiro Mita 5200 Mitsugajiri, Kumagaya-shi, Saitama Pref.

Claims (7)

[Claims] 1. A stator having a plurality of stator magnetic poles and a winding for generating a rotating magnetic field in the stator magnetic poles, a rotating shaft and a plurality of stator magnetic poles provided on the rotating shaft. A rotor having a rotating field magnet, and a magnet type brushless having a control circuit for detecting a position of a magnetic pole of the field magnet with respect to the stator and supplying a current to the winding according to the position. In the electric motor, the field magnet includes a first field magnet in which magnetic poles having different polarities are sequentially arranged in a rotation direction and a first field magnet that is rotatable relative to the first field magnet and sequentially rotates in the rotation direction. A second field magnet in which magnetic poles of different polarities are arranged, wherein the first and second field magnets face the stator magnetic pole and the first and second field magnets The phase of the combined magnetic pole of the field magnet is matched with the magnetic pole of the first field magnet. Magnet type brushless motor and having a mechanism for changing with the rotation of the rotor Te. 2. A mechanism for changing the phase of a combined magnetic pole of the first and second field magnets with respect to the magnetic pole of the first field magnet as the rotor rotates. 2. The magnet according to claim 1, wherein the first and second field magnets are arranged such that magnetic poles of the same polarity are arranged when the rotation speed is low, and the magnetic poles are shifted therefrom when the rotation speed is high. Type brushless electric motor. 3. A change in rotation speed due to a phase of a combined magnetic pole of the first and second field magnets being shifted in a rotating direction of the rotor with respect to a magnetic pole of the first field magnet. 2. The magnet type brushless electric motor according to claim 1, wherein the advance angle changes in accordance with the following. 4. A mechanism for changing the phase of a combined magnetic pole of the first and second field magnets with respect to the magnetic pole of the first field magnet as the rotor rotates. The brushless motor according to claim 1, wherein a centrifugal force is used. 5. A stator having a plurality of stator magnetic poles and a winding for generating a rotating magnetic field on the stator magnetic poles, a rotating shaft and a plurality of stator magnetic poles provided on the rotating shaft. A rotor having a rotating field magnet, and a magnet type brushless having a control circuit for detecting a position of a magnetic pole of the field magnet with respect to the stator and supplying a current to the winding according to the position. In the electric motor, the field magnet includes a first field magnet in which magnetic poles having different polarities are sequentially arranged in a rotation direction and a first field magnet that is rotatable relative to the first field magnet and sequentially rotates in the rotation direction. A second field magnet in which magnetic poles of different polarities are arranged, wherein the first and second field magnets face the stator magnetic pole and the first and second field magnets The phase of the combined magnetic pole of the field magnet is matched with the magnetic pole of the first field magnet. Mechanism for changing with the rotation of the rotor Te utilizes centrifugal force of the rotor, when the rotational speed of the rotor is low and the first second
The magnetic brushless electric motor according to claim 1, wherein the field magnets are arranged such that magnetic poles of the same polarity are arranged and the magnetic poles are deviated therefrom when the rotation speed is high. 6. A stator having a plurality of stator magnetic poles and a winding for generating a rotating magnetic field at the stator magnetic poles, a rotating shaft and a plurality of stator magnetic poles provided on the rotating shaft. A rotor having a rotating field magnet, and a magnet type brushless having a control circuit for detecting a position of a magnetic pole of the field magnet with respect to the stator and supplying a current to the winding according to the position. In the electric motor, the field magnet includes a first field magnet in which magnetic poles having different polarities are sequentially arranged in a rotation direction and a first field magnet that is rotatable relative to the first field magnet and sequentially rotates in the rotation direction. A second field magnet in which magnetic poles of different polarities are arranged, wherein the first and second field magnets face the stator magnetic pole and the first and second field magnets The phase of the combined magnetic pole of the field magnet is matched with the magnetic pole of the first field magnet. Mechanism for changing with the rotation of the rotor Te utilizes centrifugal force of the rotor, when the rotational speed of the rotor is low and the first second
The field magnets are arranged such that magnetic poles of the same polarity are arranged, and when the rotation speed is high, the magnetic poles deviate therefrom. The phase of the combined magnetic poles of the first and second field magnets is the first. A magnet-type brushless electric motor characterized in that an advancing angle changes with a change in the number of rotations by being shifted in a rotation direction of a rotor with respect to a magnetic pole of a field magnet. 7. A stator having a plurality of stator magnetic poles and a winding for generating a rotating magnetic field at the stator magnetic poles, a rotating shaft and a plurality of stator magnetic poles provided on the rotating shaft. A rotor having a rotating field magnet, and a magnet type brushless having a control circuit for detecting a position of a magnetic pole of the field magnet with respect to the stator and supplying a current to the winding according to the position. In the electric motor, the field magnet includes a first field magnet in which magnetic poles having different polarities are sequentially arranged in a rotation direction and a first field magnet that is rotatable relative to the first field magnet and sequentially rotates in the rotation direction. A second field magnet in which magnetic poles of different polarities are arranged;
And the second field magnet are opposed to the stator magnetic poles, and the phase of the combined magnetic pole of the first and second field magnets is shifted with respect to the magnetic poles of the first field magnet. The mechanism that changes with the rotation of the rotor is such that the movable side shaft of the governor connected by an elastic member moves along the hole of the fixed member fixed to the rotation shaft in the forward or reverse direction of the rotation of the rotor. A magnet type brushless electric motor characterized in that a relative rotational force is applied from a movable side shaft to a second field magnet.