JPH1023690A - Motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply form a motor into such a shape that detent torque, produced between its rotor and stator, is reduced, by constituting the opposed parts of the rotor and the stator, made of magnetic material, so that the flow of magnetic flux will vary depending on the circumferential position. SOLUTION: A radially thick portion 10b is formed at the portions 10, opposed to rotor at the ends of the salient poles 5 of a stator on one side, and a notch 10c is formed on the other side to form radially thin portions 10d. The gap between the surfaces 10a opposed to rotor and the rotor 3 is uniform in any position. The annular magnet 15 of the rotor 3 is alternately magnetized in the south pole and in the north pole in the circumferential direction. As a result, in the unexcited state before an alternating current is passed through the winding 13 on the stator, the magnetic flux from the annular magnet 15 to the portions 10 opposed to rotor is uniformly dispersed throughout the surfaces 10a opposed to rotor. This reduces detent torque and facilitates the starting at the application of power.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method in which one of a rotor and a stator is formed of a permanent magnet, and the other is excited to rotate the rotor by utilizing a magnetic attraction and a repulsive force of the rotor and the stator. Related to electric motors.

[0002]

2. Description of the Related Art Conventionally, various motors have been proposed in which one of a rotor and a stator is excited to rotate the rotor. For example, FIG. 7 shows an electric motor 31 according to the prior art. The electric motor 31 is arranged in the space of the stator set 32 having a space inside and the stator set 32, and is rotatably driven by a bearing device (not shown). It is mainly composed of a rotor set 33 supported. Stator set 3
2 is a yoke 34, a salient pole 35, and a coil bobbin 36.
And a winding coil 37. The yoke 34 is formed of a rectangular metal frame, and a plurality of salient poles 35 are integrally connected so as to protrude into a space inside the yoke 34.

The tip of the salient pole portion 35 is formed so as to extend in the circumferential direction from the center portion, and becomes a rotor facing portion 38 formed to face the outer periphery of the rotor set 33. ing. This rotor facing portion 38 is similar to that shown in FIG.
As shown in the figure, a step portion 39 is provided at a central portion in the circumferential direction, and has a different shape depending on the position in the circumferential direction with the step portion 39 as a boundary. That is, the rotor facing portion 38
Is a thick portion 40 having a large thickness in the radial direction.
And a thin portion 41 having a reduced thickness in the radial direction.
And As described above, since the rotor facing portion 38 has a shape that is asymmetrical to the left and right with the step portion 39 as a boundary, that is, a shape having the thick portion 40 and the wide thin portion 41 with a narrow interval with the rotor set 33, the motor 31 is formed so that when the stator set 32 is excited, the respective centers of the excitation torque and the detent torque do not match, and the rotor set 33 is easily rotated.

A coil bobbin 36 formed of a cylindrical body is fixed to the outer periphery of a radially intermediate portion of each of the salient pole portions 35, 35 so as to fit. The coil bobbin 36 is formed of a non-magnetic material such as a synthetic resin, and has a winding drum portion 42 formed in a cylindrical shape, and flange portions 43 and 43 projecting outward from both ends of the winding drum portion 42. Consists of A winding coil 37 is wound around the outer peripheral surface of the winding drum portion 42 a predetermined number of times. Both ends of the winding coil 37 are connected to a drive circuit (not shown) so that an external current is supplied. It has become.

On the other hand, the rotor set 33 includes a rotating shaft 44 and
An annular magnet 4 fixed to the outer periphery of the rotating shaft 44
5 mainly. The annular magnet 45 has a plurality of poles that differ depending on the circumferential position, for example, an S pole and an N pole.
Two of the poles are magnetized. And the rotor set 33 is
An annular magnet 45 is arranged in the space of the stator set 32 so as to face the facing surface of the rotor facing portion 38 of the salient pole portion 35. Magnetic flux always flows from the annular magnet 45 of the rotor set 33 of the electric motor 31 configured as described above to the salient pole portion 35 of the stator set 32. This magnetic flux serves as a force for stably stopping the rotor set 33 with respect to the stator set 32, that is, a detent torque. When a current is supplied from the outside to the winding coil 37 of the stator set 32 to excite the salient pole section 35, the annular magnet 45 and the salient pole section 35 repel and attract each other, and the rotor set 33 rotates. I do. When the magnetic field generated by the exciting operation, that is, the exciting torque exceeds the detent torque, the rotor set 33 rotates according to the magnetic field. The rotation of the rotor set 33 is facilitated by the step 39 of the stator set 32.

[0006]

In the conventional electric motor 31 constructed as described above, the thick portion 40 having a narrow gap distance (air gap) with the rotor set 33 on the left and right with the center step 39 as a boundary. And a wide thin portion 41, respectively.
A rotor facing portion 38 having an asymmetric shape is opposed to the rotor set 33. Therefore, when the magnetic flux from the annular magnet 45 of the rotor set 33 flows to the salient pole portion 35 of the stator set 32, the magnetic flux concentrates on the thick portion 40 having a small gap distance (air gap), and the magnetic flux density increases. As a result, the detent torque increases. When the detent torque increases, the force for stopping the rotor set 33 increases, and when the stator set 32 is excited to start the rotor set 33, there is a problem that the rotor set 33 is difficult to start. Further, when the magnitude of the detent torque is larger than the excitation torque, there arises a problem that the rotor set 33 does not rotate at all.

[0007] The object of the present invention, in view of the problems described above,
An object of the present invention is to provide an electric motor in which a rotor can be easily started, a magnetic flux flowing between a rotor and a stator is not concentrated, and a detent torque can be reduced.

[0008]

According to the first aspect of the present invention,
A magnetic material having a rotor, a stator opposed to the rotor, and a coil member on which a coil for exciting the rotor or the stator is wound, wherein a side of the rotor or the stator on which the coil member is mounted is other than a permanent magnet In the electric motor in which the side on which the coil member is not mounted is formed of a permanent magnet, the portions of the magnetic material facing the rotor and the stator are configured so that the flow of the magnetic flux differs depending on the circumferential position. ing. Therefore, the portion of the magnetic material facing the rotor and the stator is formed into a shape in which the rotor is easy to rotate,
That is, it is easy to make the configuration such that the detent torque generated between the rotor and the stator is suppressed to be low.

According to a second aspect of the present invention, in addition to the first aspect, the opposing portions of the rotor and the stator are formed such that the distance between the rotor and the stator is uniform in the circumferential direction. Have been. Therefore, in addition to the first aspect of the present invention, the magnetic flux is not concentrated on a part, and the detent torque as a whole can be reduced.

[0010] Further, the invention according to claim 3 is based on claim 1.
Or In addition to the invention described in 2, the rotor has an annular magnet in which a plurality of poles are magnetized in the circumferential direction, and the stator has:
It has a salient pole protruding in the radial direction facing the annular magnet, and a coil member is loaded on the salient pole, and the salient pole is asymmetric with respect to the rotation direction of the rotor, so that the flow of magnetic flux differs depending on the circumferential position. Making it easier.

According to a fourth aspect of the present invention, in addition to the third aspect of the present invention, the number of poles magnetized on the annular magnet and the number of salient poles of the stator are the same, and an alternating current generated by AC driving is used. It is synchronized with the magnetic field. For this reason, the rotor can obtain a predetermined number of rotations according to the frequency.

According to a fifth aspect of the present invention, in addition to the third or fourth aspect of the present invention, the salient poles are provided on a coil member loading portion for loading the coil member, and on both circumferential sides from the coil member loading portion. The rotor has a rotor-facing portion facing the rotor, and the thickness of the rotor-facing portion in the radial direction is asymmetric on both sides about the coil member loading portion. For this reason, if the coil member is excited so that the magnetic flux of the thin rotor-facing portion is saturated, the centers of the excitation torque and the detent torque do not match, and the rotor is easily rotated.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First to third embodiments of the present invention will be described with reference to FIGS. FIG. 1 shows an electric motor 1 according to an embodiment of the present invention.
Is mainly composed of a stator 2 having a space inside, and a rotor 3 arranged in the space inside the stator 2 to face the stator 2 and rotatably supported by a bearing device (not shown). I have.

The stator 2 is disposed so as to face the outer periphery of the rotor 3, and includes a yoke 4 made of a magnetic metal material other than a magnet, and a plurality of concretely fitted and supported by the yoke 4. Are two salient poles 5,5 and coil members 6,6
Consists of The yoke 4 is formed of a rectangular cylindrical metal frame having a space inside, and has a fitting groove 7 for fitting the salient pole 5 from one end surface to the center of the inner peripheral surface.
Is provided. In addition, the yoke 4 and the salient poles 5 are both a laminate in which a plurality of thin metal plates are laminated. FIG.
The metal bar is inserted into the small circled portion shown in FIG. 1 and is integrated by caulking one end. In addition, the yoke 4 and the salient poles 5 may be formed by so-called laminated caulking, which is caulked while laminating a metal plate with irregularities.

As shown in FIG. 2, each salient pole 5 is
The same material as the yoke 4, that is, a magnetic material other than a magnet, a fitting portion 8 serving as a root portion, a body portion 9 serving as a coil member loading portion serving as an intermediate portion, and a rotor serving as a tip portion It comprises an opposing part 10. Salient pole 5
Is fitted in the center of the inner peripheral surface of the yoke 4 by sliding the fitting portion 8 from one end surface of the yoke 4 to the depth of the fitting groove 7 with respect to the yoke 4. That is, salient pole 5
Is disposed substantially at the center of the inner peripheral surface of the yoke 4 so as to project in the radial direction. The fitting portion 8 of the salient pole 5 is
It has a shape in which the width gradually increases from the body 9 side toward the root side, and has a shape that prevents the salient poles 5 from coming off the space portion side of the yoke 4.

A coil member 6 is mounted on the outer periphery of the body portion 9 of the salient pole 5 as a coil member mounting portion. The coil member 6 includes a cylindrical winding drum 11 and the winding drum 1.
The flange portion 12 is formed so as to protrude outward from both ends of the roll 1 over the entire circumference, and the inner peripheral surface of the winding drum portion 11 is in contact with the outer circumference of the drum portion 9. Also,
The winding 13 is wound around the outer peripheral surface of the winding drum portion 11 a predetermined number of times. The winding 13 is made of a wire made of a conductive metal such as a copper wire, and both ends are connected to a drive circuit (not shown). When an alternating current (AC) is passed from the drive circuit to the winding 13, an alternating magnetic field is generated in the stator 2.

Further, the rotor facing portion 10, which is the tip portion of the salient pole 5, has a shape extending at the same length on both sides in the circumferential direction around the body portion 9. Each rotor facing portion 10 has an arc-shaped facing surface 10a facing an outer peripheral surface of an annular magnet 15 described later.
Oa is provided to face the rotor 3 so as to surround the annular magnet 15. Further, the rotor facing portion 10 has a different magnetic field flow depending on the circumferential position.
That is, the magnetic flux density is different on both sides in the circumferential direction.
It is formed in an arc shape having an asymmetric shape on the left and right around a point A (= point intersecting a line connecting the center of the body 9 and the center of the rotor 3). That is, in FIG. 2, the left side of the rotor facing portion 10 is the thick portion 1 having a large thickness in the radial direction.
0b, and to the right of the rotor facing portion 10 is formed a thin portion 10d having a notch 10c and having a small thickness in the radial direction.

Further, as shown in FIG.
It is preferable that the 0 arc-shaped opposing surface 10a is formed such that the angle C with respect to the rotation center of the rotor 3 is an arc surface of 90 to 170 °. If the angle of the facing surface 10a is set small, the magnetic flux density between the stator 2 and the rotor 3 is further increased, and the detent torque generated between the stator 2 and the rotor 3 is further increased. Conversely, if the angle of the facing surface 10a is set large, when exciting the stator 2, the magnetic flux from the stator 2 passes between the facing surfaces 10a, and the exciting torque decreases without passing through the rotor 3. Therefore, in the present embodiment, as shown in FIGS. 2 to 4, the facing surface 10a of the rotor facing portion 10 is formed in an arc within the above-described range. That is, FIG.
, The angle C is 125 °, and in the salient pole 5 of the second embodiment shown in FIG. 3, the angle C is 130 °. In the salient pole 5 of the third embodiment shown in FIG.
Is set to 170 °. Here, from the viewpoint of both the detent torque and the magnetic flux leakage, the angle C is more preferably from 100 ° to 150 °, and most preferably from 110 ° to 140 °.

In each of the first to third embodiments, the gap distance (air gap) between the outer periphery of the annular magnet 15 and the facing surface 10a, that is, the distance between the rotor 3 and the stator 2 is determined by the distance of the facing surface 10a. It is formed uniformly at any position. In addition, the rotor facing portion 10 includes a thick portion 10b.
Is set to be twice the radial thickness y of the thin portion 10d.

On the other hand, the rotor 3 is mainly composed of a rotating shaft 14 and an annular annular magnet 15 formed of a rare earth permanent magnet fixed to the outer periphery of the rotating shaft 14. In addition, another magnet such as an iron oxide-based magnet may be used for the annular magnet 15. And the rotor 3 has the rotating shaft 1
4 is arranged in the space of the stator 2 such that the axial direction is orthogonal to the direction in which the salient poles 5 of the stator 2 project, and the outer periphery of the annular magnet 15 faces the rotor facing portion 10 of the salient poles 5. The annular magnet 15 has a plurality of poles, S poles and N poles in the present embodiment, one by one in the circumferential direction.
Polarized. The rotor 3 has both ends of a rotating shaft 14 rotatably supported by a bearing device (not shown).

The electric motor 1 thus configured is supplied with an alternating current (AC) by a drive circuit (not shown).
The stator 2 is excited. When no alternating current is flowing through the motor 1, that is, when the motor 1 is not excited, magnetic flux flows from the annular magnet 15 of the rotor 3 to the rotor facing portion 10 of the salient pole 5. The magnetic flux from the annular magnet 15 to the rotor facing portion 10 flows so as to be evenly distributed to each portion of the facing surface 10a of the rotor facing portion 10. Therefore, the magnetic flux is not concentrated, and the detent torque generated between the stator 2 and the rotor 3 is reduced as a whole, and the rotor 3 is easily rotated.

Further, a predetermined amount of alternating current flows through the winding 13 wound around the coil member 6 from the drive circuit to excite the stator 2 and generate an exciting torque. Since the exciting torque is larger than the detent torque which is a force for keeping the rotor 3 stationary, the rotor 3 can obtain rotation according to the frequency of the exciting torque. As mentioned above,
The rotor facing portion 10 is formed asymmetrically on the left and right around the point A in FIG.
Since the thickness in the radial direction is formed smaller than 0b, the thin portion 10d is magnetically saturated by applying a current to the winding 13 and adding a magnetic flux generated by the coil member 6 to a magnetic flux generated by the rotor 3. . As a result, the magnetic flux of the salient poles 5 flows toward the thick portion 10b that has not been magnetically saturated. As described above, the flow of the magnetic flux differs depending on the position in the circumferential direction of the facing surface 10a of the salient pole 5 depending on the presence or absence of energization. Then, as a result, the change in the flow of the magnetic flux of the salient pole 5 causes the center position of the detent torque and the winding 13
Is different from the center position of the exciting torque generated by the energization of the rotor, the rotating torque is generated, and the rotor 3 is easily rotated in the circumferential direction.

The salient poles 5 of the stator 2 thus configured
When one is excited to the N pole and the other to the S pole, the annular magnet 1 facing the rotor facing portion 10 of the salient pole 5
5 is repelled or attracted to the rotor facing portion 10,
The rotor 3 rotates in either the left or right circumferential direction as shown by the arrow B. Thereafter, the rotor 3 repeats attraction and repulsion by the alternating magnetic field, and continuously rotates in the circumferential direction. The opposed salient poles 5 and 5 are excited to different magnetic poles when excited.

The second and third embodiments described above are different from the first embodiment only in the configuration of the rotor facing portion 10 of the salient pole 5, and the other configurations are the same as those of the first embodiment. This is similar to the embodiment. The second embodiment shown in FIG.
From the length from point A of thick part 10b, A of thin part 10d
The length from the point is longer. For this reason, the detent torque is further dispersed and reduced,
In addition, the difference between the center of the detent torque and the center of the excitation torque is increased, and the starting torque can be reduced.
Is easy to start. Also, the third type shown in FIG.
In this embodiment, both the thick part 10b and the thin part 10d have a longer length from the point A. For this reason, the detent torque is further reduced, and the starting torque can be significantly reduced.

The present invention configured as described above is not limited to the above-described embodiments, and various modifications can be made within the scope of the present invention. A fourth embodiment of the present invention will be described with reference to FIG. FIG. 5 shows an electric motor 16 according to a fourth embodiment of the present invention. The electric motor 16 has a space inside and a cutout 18 partially cut away. It mainly comprises a stator 17, which is shaped like a horseshoe, and a rotor 19 that is arranged in a notch 18 in the stator 17 and rotatably supported by a bearing device (not shown).

The stator 17 includes a yoke 20 formed of a magnetic metal material other than a magnet and having a substantially U-shape.
0, two salient poles 21 and 2 fitted and supported inside the distal end portion
1 and coil members 22 and 22. York 2
A fitting groove 23 for fitting the salient pole 21 is provided from one end surface to the center of the inner peripheral surface inside the front end portion of the zero. The yoke 20 and the salient poles 21 are both a laminated body in which a plurality of thin metal plates are laminated. The yoke 20 and the salient poles 21 are provided with irregularities on the metal plate, and are caulked while being laminated. It is formed by laminated caulking. .

Each salient pole 21 is made of the same material as the yoke 20,
That is, while being formed from a magnetic material other than a magnet,
It comprises a fitting portion 24 serving as a root portion and a rotor facing portion 25 serving as a tip portion. The salient pole 21 is configured such that the fitting portion 24 is formed in the fitting groove 2 from one end face of the yoke 20 with respect to the yoke 20.
3 is fitted to the center of the inner peripheral surface of the yoke 20 by sliding it to the back. In other words, the salient poles 21 are disposed substantially at the center of the inner peripheral surface inside the distal end portion of the yoke 20 so as to project in the radial direction of the rotor 19 described later. Note that the fitting portion 24 of the salient pole 21 is
And has a shape in which the width gradually increases from the root toward the outside, so that the salient poles 21 are prevented from coming out of the yoke 20 to the notch portion 18 side.

Coil members 22, 22 are mounted at two places on the outer periphery of a part of the yoke 20. The coil member 22 includes a cylindrical winding drum 26 and flanges 27 formed to protrude outward from both ends of the winding drum 26 over the entire circumference. 2
6 is in contact with the outer periphery of the yoke 20. Also,
The winding 28 is wound around the outer peripheral surface of the winding drum 27 a predetermined number of times. The winding 28 is made of a wire made of a conductive metal such as a copper wire in a linear shape, and both ends are connected to a drive circuit (not shown). Then, when an alternating current is supplied to the winding 28 from the drive circuit, the stator 17 is excited.

Further, the rotor facing portion 25, which is the tip of each salient pole 21, is formed closer to the notch 18 of the stator 17 than the end of the fitting portion 24. Each rotor opposing portion 25 has an arc-shaped opposing surface 25a opposing an outer peripheral surface of an annular magnet 29 described later. The opposing surfaces 25a oppose the rotor 19 so as to surround the annular magnet 29. Is provided. Further, a pair of upper and lower rotor facing portions 25, 25 are connected to a point D in FIG.
It is formed in an arc shape having an asymmetric shape on the left and right with respect to a point. That is, the left side of the upper rotor facing portion 25 in FIG. 5 is formed by the thick portion 25b having a large thickness in the radial direction, and the right side is formed by the notch portion 25c and the thin thickness in the radial direction. It is formed of a thin portion 25d. The left side of the lower rotor facing portion 25 is formed of a notch 25c 'and a thin portion 25d' having a small thickness in the radial direction, and the right side has a large thickness in the radial direction. It is formed of a meat portion 25b '.
The gap distance (air gap) between the opposing surface 25a and the outer periphery of the annular magnet 29 is uniform at any position on the opposing surface 25a.

On the other hand, the rotor 19 is mainly composed of a rotating shaft 30 and an annular annular magnet 29 formed of a rare earth permanent magnet fixed to the outer periphery of the rotating shaft 30. In addition, another magnet such as an iron oxide-based magnet may be used for the annular magnet 15. Further, the rotor 19 has a configuration in which the axial direction of the rotating shaft 30 is orthogonal to the direction in which the salient poles 21 of the stator 17 protrude, and the outer periphery of the annular magnet 29 faces the rotor facing portion 25 of the salient poles 21. It is arranged in the notch 18. In the annular magnet 29,
A plurality of poles, i.e., S poles and N poles, are alternately polarized one by one in the circumferential direction. The rotor 19 has both ends of a rotating shaft 30 rotatably supported by a bearing device (not shown).

The horseshoe-shaped electric motor 16 constructed as described above
Are supplied with an alternating current by a drive circuit (not shown), and the stator 17 is excited. When no AC current is applied to the motor 16, that is, when the motor 16 is not excited, the annular magnet 2
Magnetic flux flows from 9 to the rotor facing portion 25 of the salient pole 21. From the annular magnet 29 to the rotor facing portion 25
Is flowing so as to be evenly distributed to each part of the facing surface 25a of the rotor facing part 25. Therefore, the magnetic flux does not concentrate on a part, and the detent torque generated between the stator 17 and the rotor 19 is reduced as a whole, and the rotor 19 is easily rotated.

Further, a predetermined amount of alternating current flows through the winding 28 wound around the coil member 22 from the drive circuit to excite the stator 17 and generate an exciting torque. Since this exciting torque is larger than the detent torque which is a force for keeping the rotor 19 stationary, the rotor 19 is configured to obtain rotation according to the frequency of the exciting torque. As described above, the rotor facing portion 25 is formed asymmetrically on the left and right with respect to the points D and E in FIG. 5, and the thin portion 25d is formed to be thinner in the radial direction than the thick portion 25b. The thin part 25d
When the winding 28 is energized, the magnetic flux generated by the coil member 22 is added to the magnetic flux generated by the rotor 19 and is magnetically saturated. As a result, the magnetic flux of the salient poles 21 flows toward the thick portion 25b that is not magnetically saturated. Thus, depending on whether or not the winding 28 is energized, the salient pole 2
The flow of the magnetic flux of the one opposing surface 25a differs depending on the position in the circumferential direction. As a result, the center position of the detent torque differs from the center position of the excitation torque generated by energization of the winding 28 due to the change in the flow of the magnetic flux of the salient poles 21, and rotation torque is generated. It becomes easy to rotate.

The present invention thus configured is not limited to the above-described embodiments, and various modifications can be made within the scope of the present invention. For example, the first
In the fourth to fourth embodiments, except for the case of the second embodiment, the opposing surfaces 10a and 25a of the salient poles 5 and 21 have a shape extending from the center portion by the same length in the circumferential direction. However, as shown in FIG. 6, the angle C is set to 150 °, and the thin portions 10d and 2 are defined with respect to a line connecting the center of the rotors 3 and 19 and the point A.
The 5d side may be 80 ° and the other side may be 70 °. In addition, the facing surface 25a of the salient pole 21 used in the fourth embodiment of the present invention is set at an angle C of 90 ° to 170 °.
Within the range of °, various values can be adopted and D
The lengths on both sides of point E and point E may be different. Further, for example, in the present embodiment, the gap distance between the opposing surfaces 10a, 25a of the rotor opposing portions 10, 25 of the salient poles 5, 21 and the outer peripheral surfaces of the annular magnets 15, 29 is made uniform. In particular, it need not be strictly uniform. That is,
The magnetic flux from the annular magnets 15, 29 is applied to the opposing surfaces 10a,
What is necessary is just to have the effect of not concentrating on the limited position of 25a.

Further, in each of the above embodiments,
The S pole and the N pole, which are the magnetized poles of the annular magnets 15 and 29, are each one pole, and the salient poles 5 and 21 are 2 poles.
Motors 1 and 16 are annular magnets 1
Although the poles 5 and 29 and the salient poles 5 and 21 are constituted by the same number of AC synchronous drives, the present invention is not particularly limited to this. Further, in each of the above-described embodiments, an alternating current is applied to the windings 13 and 28 to excite the stators 2 and 17, but the stators 2 and 17 are made permanent magnets and the rotors 3 and 19 are excited. It may be configured as follows. Note that the notch 10c is cut further inward from the trunk 9, but may be a notch up to the trunk 9 or a notch that does not reach the trunk 9. As long as the thin portion 10d can be formed, various means can be adopted.

It should be noted that each of the above-described embodiments cannot be constituted by a normal permanent magnet type AC synchronous motor.
It has a large shape. That is, the protrusion amount of the salient pole 5 including the body 9 of the salient pole 5 and the rotor facing portion 10 shown in FIG. 2 and the like is about 2.5 cm to 3.1 cm. The thickness of the body 9 in the circumferential direction of the rotor 3 and the thickness in the axial direction of the rotor 3 are both about 2 cm. However, the present invention is applicable to other dimensions in addition to such dimensions.

[0036]

According to the first aspect of the present invention, the portion of the magnetic material facing the rotor and the stator is configured so that the flow of magnetic flux differs depending on the circumferential position. It is easy to configure the magnetic material portion to have a shape that suppresses the detent torque generated between the rotor and the stator so that the rotor can be easily rotated. Therefore, it is possible to easily provide a highly reliable electric motor in which the rotor easily rotates.

According to the second aspect of the present invention, in addition to the first aspect of the present invention, the interval between the rotor and the stator is formed so as to be uniform in the circumferential direction. That is, it is possible to provide a motor having a high power without a decrease in rotational torque.

Further, according to the third aspect of the present invention, since the salient poles are made asymmetrical so that the flow of the magnetic flux can be easily varied depending on the position in the circumferential direction, the flow of the magnetic flux differs depending on the position in the circumferential direction. Can be easily achieved.

According to the fourth aspect of the present invention, since the number of poles magnetized on the annular magnet and the number of salient poles of the stator are set to the same number by AC drive and synchronous drive, the rotor is fixed. The number of rotations can be set, and the motor can be used widely.

According to the fifth aspect of the present invention, the radial thickness of the rotor-facing portion is asymmetric on both sides about the coil loading portion, so that the stator can be excited and not excited. Since the flow of the magnetic flux is made different depending on the position in the circumferential direction, it is easy to generate a rotational torque. Therefore, there is no so-called dead point (magnetically stable point) in which the rotor cannot rotate at the time of startup, and a highly reliable electric motor in which the rotor easily rotates in the circumferential direction can be provided. Moreover, since the parts other than the rotor facing part can be made symmetrical, the loading of the coil and the assembling of the salient poles can be easily performed as in the conventional case.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an electric motor according to a first embodiment of the present invention.

FIG. 2 is a sectional view of the electric motor shown in FIG. 1 taken along line AA ′.

FIG. 3 is a cross-sectional view illustrating a salient pole and a rotor according to a second embodiment of the present invention.

FIG. 4 is a cross-sectional view illustrating a salient pole and a rotor according to a third embodiment of the present invention.

FIG. 5 is a sectional view showing an electric motor according to a fourth embodiment of the present invention.

FIG. 6 is a sectional view showing a modified example of salient poles used in the electric motor according to the first to third embodiments of the present invention.

FIG. 7 is a perspective view showing a conventional electric motor.

FIG. 8 is a cross-sectional view of the electric motor shown in FIG. 7 taken along line HH ′.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric motor 2 Stator 3 Rotor 4 Yoke 5 Salient pole 6 Coil member 7 Fitting groove 9 Body (coil member loading part) 10 Rotor facing part 13 Winding 15 Ring magnet

Claims (5)

[Claims] 1. A motor comprising: a rotor; a stator facing the rotor; and a coil member on which a winding for exciting the rotor or the stator is wound, wherein the coil member of the rotor or the stator is In a motor in which the mounted side is formed of a magnetic material other than a permanent magnet, and the side on which the coil member is not mounted is formed of a permanent magnet, the portion of the magnetic material opposed to the rotor and the stator, An electric motor characterized in that the flow of magnetic flux differs depending on the circumferential position. 2. The electric motor according to claim 1, wherein a portion where the rotor and the stator face each other is formed such that a distance between the rotor and the stator is uniform in a circumferential direction. . 3. The rotor has an annular magnet in which a plurality of poles are magnetized in a circumferential direction. The stator has a salient pole projecting in a radial direction facing the annular magnet. Loading the coil member on a pole,
3. The electric motor according to claim 1, wherein the salient poles are asymmetric with respect to the rotation direction of the rotor so that the flow of the magnetic flux is easily changed depending on the position in the circumferential direction. 4. The apparatus according to claim 3, wherein the number of poles magnetized on said annular magnet is equal to the number of salient poles of said stator, and AC drive and synchronous drive are performed.
An electric motor as described. 5. The rotor according to claim 1, wherein the salient pole has a coil member loading portion for loading the coil member, and a rotor facing portion extending from the coil member loading portion to both circumferential sides and facing the rotor. 5. The electric motor according to claim 3, wherein the thickness of the facing portion in the radial direction is asymmetric on both sides around the coil member loading portion.