JP3798677B2 - Brushless motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a brushless motor.
[0002]
[Prior art]
Currently, development of motors is diverse, for example, development of micro motors, higher accuracy of stepping motors, reduction of power consumption, and higher torque. In particular, small motors with low power consumption and high torque are widely used in the fields of automobiles, OA equipment, vending equipment, medical / welfare equipment, and the like.
[0003]
Usually, most of the motors used in these are motors using permanent magnets, and since the technology is quite mature, it is difficult to achieve dramatic improvements in efficiency and size and torque.
[0004]
For example, a motor using a hybrid magnet is known in order to reduce the size and increase the torque. For example, Japanese Patent Application Laid-Open No. 2000-150228 discloses a stepping motor including a hybrid magnet including both a coil and a permanent magnet. As shown in FIG. 10, in the hybrid magnet 61 of this publication, in a U-shaped iron core 62, a coil 63 is wound around a body portion 62a provided on the stator so as to extend in the axial direction of the motor. . Magnetic members 64 are joined to both ends of the body portion 62a from both ends of the arm portions 62b extending in the radial direction of the motor, and a permanent magnet 65 is sandwiched between the magnetic members 64. The permanent magnets 65 are arranged so as to be aligned in the radial direction of the coil 63 and the motor.
[0005]
[Problems to be solved by the invention]
However, in the hybrid magnet 61 of this publication, since the coil 63 and the permanent magnet 65 are configured to be aligned in the radial direction of the motor, there is a problem that it is difficult to miniaturize the motor in the radial direction.
[0006]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a brushless motor capable of reducing the size and increasing the torque and reducing the size in the radial direction.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is a rotor in which a plurality of permanent magnets magnetized so as to change their polarities in the radial direction are arranged in the circumferential direction so that adjacent magnetic poles are different. And a cylindrical portion facing one of the outer peripheral surface and the inner peripheral surface of the rotor, a plurality of fixed iron cores provided in a circumferential direction on the surface of the cylindrical portion facing the rotor, and wound around the fixed iron core, A brushless motor comprising a stator having a hybrid magnet composed of a coil that is sequentially fed so as to rotate the rotor and a fixed permanent magnet that is arranged so that the polarity changes in the circumferential direction between the fixed iron cores. The fixed iron core is formed in a substantially U shape with a protruding iron core formed so that a base end thereof is connected to the cylindrical portion and a front end protrudes toward the rotor and the coil is wound thereon. Been The coil comprises a connecting iron core that has an end portion facing the cylindrical portion, the end portion of the connecting iron core is magnetically insulated from the cylindrical portion, and the fixed permanent magnet is adjacent to the connection at both ends thereof The gist is that the fixed permanent magnets that are in contact with the iron core and are adjacent to each other are arranged so that the same magnetic poles face each other.
[0008]
According to this invention, in a state where the coil is not supplied with power, the magnetic lines of force of the fixed permanent magnet of the hybrid magnet constitute a closed circuit passing through the connecting iron core, the protruding iron core, and the cylindrical portion, so that no magnetic force acts on the rotor side. .
[0009]
In a state where the coil is supplied with power, the magnetic field lines of the fixed permanent magnet are bent by the magnetic force of the electromagnet and directed toward the rotor. For this reason, when the coil is fed, a strong magnetic force, which is the sum of the magnetic force of the electromagnet and the magnetic force of the fixed permanent magnet, acts on the rotor side from the hybrid magnet. With this strong magnetic force, the coils are sequentially fed, whereby the permanent magnet of the rotor receives a tensile force and a repulsive force, and the rotor is rotated.
[0010]
I want to make the magnetic flux density of the brushless motor stator as strong as possible. In addition, when the amount of current is increased, heat generation increases and energy loss occurs. Therefore, by providing a hybrid magnet having a fixed permanent magnet, it is possible to obtain a brushless motor stator that is strong in torque and generates little heat.
[0011]
Further, since the fixed permanent magnet and the coil are arranged in the circumferential direction, the size is reduced in the radial direction. Therefore, it is possible to reduce the size and increase the torque, and to reduce the size in the radial direction.
[0012]
Further, when the inner peripheral surface of the cylindrical portion faces the rotor, the brushless motor is an inner rotor type. On the contrary, when the outer peripheral surface of the cylindrical portion faces the rotor, the brushless motor is an outer rotor type.
[0013]
The invention according to claim 2 is characterized in that, in the invention according to claim 1, the number of magnetic poles of the permanent magnet of the rotor is four in the circumferential direction and the number of the protruding iron cores is six.
According to the present invention, power is supplied to two adjacent coils, and a predetermined permanent magnet of the rotor is rotated by a repulsive force and a tensile force. It is located between two coils that can apply a tensile force and a repulsive force to the permanent magnet. For this reason, by next feeding these two coils, the rotor can be effectively rotated, and the simplest and best arrangement can be achieved.
[0014]
According to a third aspect of the present invention, there is provided a rotor having a plurality of radial projections, a cylindrical portion facing one of the outer peripheral surface and the inner peripheral surface of the rotor, and a circumferential direction on a surface of the cylindrical portion facing the rotor. A plurality of fixed iron cores, coils wound around the fixed iron cores and sequentially fed so as to rotate the rotor, and fixedly arranged so that the polarity changes in the circumferential direction between the fixed iron cores A brushless motor comprising a stator having a hybrid magnet comprising a permanent magnet, wherein the fixed iron core is formed such that a base end is connected to the cylindrical portion and a tip protrudes toward the rotor. The protruding iron core around which the coil is wound, and a connecting iron core that is formed in a substantially U shape and covers the coil, and an end portion of which faces the cylindrical portion, and the end portion of the connecting iron core is the cylindrical portion And magnetism Insulated, the fixed permanent magnet, at its ends, abuts on the connecting iron core adjacent the said fixed permanent magnets adjacent same magnetic poles is summarized in that arranged so as to face.
[0015]
According to the present invention, in the state where the coil is not supplied with power, the magnetic lines of force of the fixed permanent magnet constitute a closed circuit passing through the connecting iron core, the protruding iron core, and the cylindrical portion, as in the first aspect of the invention. Magnetic force does not act on the rotor side. Further, in a state where the coil is fed, the magnetic lines of force of the fixed permanent magnet are bent by the magnetic force of the electromagnet and directed toward the rotor side. For this reason, when the coil is fed, a strong magnetic force, which is the sum of the magnetic force of the electromagnet and the magnetic force of the fixed permanent magnet, acts on the rotor side from the hybrid magnet. Due to the strong magnetic force, the protrusions of the rotor receive a tensile force, and the rotor is rotated by sequentially supplying power to the coils.
[0016]
Thus, by providing a hybrid magnet in the stator, torque is strong and heat generation can be reduced. Therefore, even if a permanent magnet is not provided in the rotor, a small and high torque can be achieved. Moreover, since the rotor is not provided with a permanent magnet, the manufacturing cost can be reduced accordingly.
[0017]
Further, since the fixed permanent magnet and the coil are arranged in the circumferential direction, the size is reduced in the radial direction. Therefore, it is possible to reduce the size and increase the torque, and to reduce the size in the radial direction. The brushless motor is an inner rotor type when the inner peripheral surface of the cylindrical portion faces the rotor, and the outer rotor type when the outer peripheral surface of the cylindrical portion faces the rotor.
[0018]
The gist of the invention according to claim 4 is that, in the invention according to claim 3, the circumferential width of the protrusion of the rotor and the circumferential width of the connecting iron core are substantially the same.
[0019]
According to this invention, when the rotor protrusion is pulled by the magnetic force of the hybrid magnet and the rotor protrusion faces the connecting iron core that covers the coil in the state of the electromagnet, the rotor iron core and the connecting iron core are Opposite in almost no direction. For this reason, the leakage of magnetic flux is reduced between the protrusion of the rotor and the connecting iron core, and a high torque can be effectively achieved.
[0020]
The invention according to claim 5 is the gist of the invention according to claim 3 or claim 4 in which the circumferential width of the projection of the rotor is larger than the interval between the circumferential end faces of the adjacent connecting cores. To do.
[0021]
According to this invention, when a certain protrusion of the rotor is pulled by the magnetic force of the hybrid magnet and the rotor rotates, and this protrusion faces the connecting iron core that covers the coil in the state of the electromagnet, another protrusion of the rotor is It faces another connecting iron core in a part in the circumferential direction. For this reason, next, when the coil covered with the other connecting iron core is fed, the magnetic flux passes between the other protrusion and the other connecting iron core in a part of the opposing circumferential direction. The protrusion is pulled and the rotor continues to rotate. Therefore, the tensile force can be continuously applied to the rotor, and the rotor can be rotated smoothly.
[0022]
The invention according to claim 6 is the invention according to any one of claims 3 to 5, wherein the number of protrusions of the rotor is four in the circumferential direction and the number of protrusion iron cores is six. The gist of the coil wound around the iron core is a three-phase coil in which projecting iron cores facing each other at 180 ° are fed simultaneously.
[0023]
According to the present invention, when a coil of a certain phase is supplied with power, and the two protrusions of the rotor are pulled and opposed to the two coil sides constituting this phase, the remaining two protrusions of the rotor are respectively different from each other. Located between the coils. For this reason, when the coil of another phase is supplied with power next time, the rotor can be effectively rotated, and the simplest arrangement can be obtained.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
Hereinafter, a first embodiment in which the present invention is embodied in an inner rotor type brushless motor will be described with reference to FIGS.
[0025]
1A is a schematic cross-sectional view of a brushless motor, and FIG. 1B is a partial cross-sectional schematic side view taken along line IB-IB in FIG. FIG. 5 is a graph showing the relationship between the rotation angle of the rotor and the energized state of the coil.
[0026]
As shown in FIG. 1B, the brushless motor 11 includes a motor housing 12, and the motor housing 12 includes a bottomed cylindrical yoke 13 and an end frame 14. A bearing is fixed to the center of each of the bottom of the yoke 13 and the end frame 14. A rotor 18 is accommodated in a space formed by the yoke 13 and the end frame 14. The rotating shaft 19 of the rotor 18 is rotatably supported by the both bearings.
[0027]
As shown in FIG. 1A, the rotor core 20 of the rotor 18 is made of iron and is formed in a cylindrical shape, and a plurality of permanent magnets are attached to the peripheral surface of the rotor core 20 so as to be integrally rotatable. In this embodiment, four arcuate plate-like permanent magnets are attached to the rotor core 20. These permanent magnets are referred to as a first rotating permanent magnet 21, a second rotating permanent magnet 22, a third rotating permanent magnet 23, and a fourth rotating permanent magnet 24. The first to fourth rotating permanent magnets 21 to 24 are formed to have the same length in the circumferential direction and are adjacent to each other. For this reason, each of the first to fourth rotating permanent magnets 21 to 24 has an angle formed by the center of the rotor 18 and both end faces of 90 °. As shown to Fig.1 (a), when the rotor 18 is seen from the end frame 14 side, the 1st-4th rotation permanent magnets 21-24 are arrange | positioned in order clockwise.
[0028]
The first to fourth rotating permanent magnets 21 to 24 are magnetized so that their polarities change in the radial direction. In the drawing, only the radially outer magnetic pole is shown, and the radially inner magnetic pole is not shown. Yes.
[0029]
The 1st rotation permanent magnet 21 is arranged so that the diameter direction outside may become N pole. In this embodiment, the N pole of the first rotating permanent magnet 21 is referred to as the N1 pole, the S pole of the second rotating permanent magnet 22 is the S1 pole, the N pole of the third rotating permanent magnet 23 is the N2 pole, and the fourth rotating permanent magnet. The south pole of the magnet 24 is referred to as the south pole.
[0030]
The first to fourth rotating permanent magnets 21 to 24 are formed to have the same axial length as the rotor core 20.
As shown in FIGS. 1A and 1B, a protruding iron core 27 is attached to the inner peripheral surface of the cylindrical portion 13 a of the yoke 13. A plurality of protruding iron cores 27 are arranged in the circumferential direction of the yoke 13. In this embodiment, six projecting iron cores 27 are attached in the circumferential direction of the yoke 13 at equiangular intervals (60 ° intervals). Each protruding iron core 27 is formed such that the base end is attached to the inner peripheral surface of the cylindrical portion 13 a and the tip protrudes toward the rotor 18.
[0031]
Each protruding iron core 27 is wound with a winding to form a coil. In this embodiment, the upper left coil in FIG. 1A is referred to as a first coil L1, and the other coils are the second coil L2, the third coil L3, the fourth coil in the clockwise direction in FIG. These are referred to as a coil L4, a fifth coil L5, and a sixth coil L6.
[0032]
1st coil L1, 3rd coil L3. The fifth coil L5 is wound around the protruding iron core 27 so that the radially inner side becomes the N pole and the radially outer side becomes the S pole when fed. Conversely, the second coil L2, the fourth coil L4. The sixth coil L6 is wound around the protruding iron core 27 so that when fed, the radially inner side becomes the S pole and the radially outer side becomes the N pole.
[0033]
Each protruding iron core 27 is formed integrally with the connecting iron core 28. Each connecting iron core 28 is substantially U-shaped and is formed so as to cover each of the first to sixth coils L1 to L6. The end of the connecting iron core 28 faces the cylindrical portion 13a. The tip of the protruding iron core 27 is continuous with the central portion of the connecting iron core 28. Further, an arc plate-like insulator 29 is attached to the cylindrical portion 13a of the yoke 13 between the first to sixth coils L1 to L6, and the end of the connecting iron core 28 is connected to the cylindrical portion 13a by the insulator 29. Magnetically insulated. The protruding iron core 27 and the connecting iron core 28 constitute a fixed iron core.
[0034]
A permanent magnet is sandwiched between adjacent connecting cores 28. In this embodiment, the permanent magnet sandwiched between the first coil L1 and the second coil L2 is referred to as a first fixed permanent magnet 31, and the other permanent magnets are sequentially second in the clockwise direction in FIG. The fixed permanent magnet 32, the third fixed permanent magnet 33, the fourth fixed permanent magnet 34, the fifth fixed permanent magnet 35, and the sixth fixed permanent magnet 36 are referred to. Each of the first to sixth fixed permanent magnets 31 to 36 is magnetically insulated from the cylindrical portion 13 a by an insulator 29. Each of the first to sixth fixed permanent magnets 31 to 36 is formed so that the circumferential width is smaller than the circumferential width of the connecting iron core 28.
[0035]
Each of the first to sixth fixed permanent magnets 31 to 36 is formed so that the polarity changes in the circumferential direction. The first fixed permanent magnet 31 is formed so that the first coil L1 side is an N pole and the second coil L2 side is an S pole. The second fixed permanent magnet 32 is formed so that the second coil L2 side is an S pole and the third coil L3 side is an N pole. The third fixed permanent magnet 33 is formed such that the third coil L3 side is an N pole and the fourth coil L4 side is an S pole. Thus, the 1st-6th fixed permanent magnets 31-36 are arrange | positioned so that the same magnetic pole may oppose between adjacent permanent magnets.
[0036]
A hybrid magnet is configured by the cylindrical portion 13a of the yoke 13, the protruding iron core 27, the connecting iron core 28, the first to sixth coils L1 to L6, and the first to sixth fixed permanent magnets 31 to 36. The hybrid magnet and the motor housing 12 constitute a stator.
[0037]
As shown in FIG. 1B, a hall element 41 is attached to the end frame 14 via a bracket so as to face the rotor 18. The brushless motor 11 can detect the position of the rotor 18 by detecting a change in the magnetic flux of the first to fourth rotating permanent magnets 21 to 24 by the rotation of the rotor 18 by the Hall element 41 and performing a predetermined calculation. ing.
[0038]
In this embodiment, the rotation angle θ of the rotor 18 is rotated with the central portion of the second rotating permanent magnet 22 having the S1 pole facing the first fixed permanent magnet 31 as shown in FIG. The angle θ is set to 0 °. The first to sixth coils L1 to L6 are configured to be fed based on the rotational position of the rotor 18 detected by the Hall element 41 as shown in the graph of FIG.
[0039]
Next, the operation of the brushless motor configured as described above will be described.
As shown in FIG. 2, in a state where the first to sixth coils L1 to L6 are not supplied with power, the magnetic lines of force of the first fixed permanent magnet 31 are on the first fixed permanent magnet 31 side in the connecting core 28 adjacent to the N pole. , The protruding iron core 27 around which the first coil L1 is wound, the cylindrical portion 13a, the protruding iron core 27 around which the second coil L2 is wound, and the connecting iron core 28 adjacent to the S pole on the first fixed permanent magnet 31 side. Construct a closed circuit through the part. For this reason, the magnetic force of the first fixed permanent magnet 31 does not act on the rotor 18 side.
[0040]
Similarly, the magnetic lines of force of the second fixed permanent magnet 32 are the portion on the second fixed permanent magnet 32 side in the connecting core 28 adjacent to the N pole, the protruding core 27 around which the second coil L2 is wound, the cylindrical portion 13a, The projecting iron core 27 around which the three coils L3 are wound and the connecting iron core 28 adjacent to the S pole form a closed circuit that passes through the portion on the second fixed permanent magnet 32 side. For this reason, the magnetic force of the second fixed permanent magnet 32 does not act on the rotor 18 side. Further, the magnetic field lines by the first fixed permanent magnet 31 and the magnetic field lines by the second fixed permanent magnet 32 pass through the protruding iron core 27 around which the second coil L2 is wound so as to be directed radially inward.
[0041]
Similarly, the magnetic lines of force of the third fixed permanent magnet 33 are directed outward in the radial direction inside the protruding iron core 27 around which the third coil L3 is wound, and through the cylindrical portion 13a, the protrusion around which the fourth coil L4 is wound. A closed circuit is formed in the iron core 27 toward the inside in the radial direction, and the magnetic force of the third fixed permanent magnet 33 does not act on the rotor 18 side. For this reason, the magnetic force lines by the second fixed permanent magnet 32 and the magnetic lines of force by the third fixed permanent magnet 33 pass through the protruding iron core 27 in the third coil L3 so as to go outward in the radial direction.
[0042]
Thus, in the state where the first to sixth coils L1 to L6 are not supplied with power, the magnetic lines of force of the first to sixth fixed permanent magnets 31 to 36 are the connecting iron core 28, the protruding iron core 27, and the cylindrical portion of the yoke 13. Since it forms a closed circuit passing through 13a, it does not act on the rotor 18 side.
[0043]
Further, the magnetic lines of force of the fixed permanent magnets pass through the protruding iron core 27 around which the first coil L1, the third coil L3, and the fifth coil L5 are wound so as to go outward in the radial direction. Further, the magnetic lines of force of the fixed permanent magnets pass through the protruding iron core 27 wound around the second coil L2, the fourth coil L4, and the sixth coil L6 so as to be directed radially inward.
[0044]
As shown in FIG. 3, when the rotation angle of the rotor 18 is 0 °, the first coil L <b> 1 and the second coil L <b> 2 are supplied with power based on the detection of the rotation angle by the Hall element 41.
[0045]
When the first coil L1 is fed to become an electromagnet, a magnetic field is generated such that the radially inner side of the first coil L1 becomes the N pole and the radially outer side becomes the S pole. Due to the magnetic field generated by the electromagnet, magnetic lines of force pass through the protruding iron core 27 around which the first coil L1 is wound in the radially inward direction opposite to the case of FIG. For this reason, the magnetic lines of force of the first and sixth fixed permanent magnets 31 and 36 cannot form a closed circuit passing through the protruding iron core 27 around which the first coil L1 is wound, and the magnetic lines of force emerging from the N poles of both magnets are It goes to the rotor 18 side together with the magnetic field lines of the electromagnet by one coil L1.
[0046]
For this reason, in the connecting iron core 28 covering the first coil L1, the strong magnetic force obtained by adding the magnetic force of the electromagnet by the first coil L1 and the magnetic force by the first and sixth fixed permanent magnets 31 and 36 is the rotor 18 side. Act on.
[0047]
Further, when the second coil L2 is fed to become an electromagnet, a magnetic field is generated such that the radially inner side of the second coil L2 becomes the S pole and the radially outer side becomes the N pole. Due to the magnetic field generated by the electromagnet, magnetic field lines pass through the protruding iron core 27 around which the second coil L2 is wound in the radially outward direction, which is opposite to the case of FIG. For this reason, the magnetic field lines of the first and second fixed permanent magnets 31 and 32 cannot form a closed circuit passing through the protruding iron core 27 around which the second coil L2 is wound, and the magnetic field lines entering the S pole of both magnets are Together with the magnetic field lines of the electromagnet by the two coils L2, each S pole enters from the rotor 18 side.
[0048]
For this reason, the connecting iron core 28 covering the second coil L2 similarly has a strong magnetic force obtained by summing the magnetic force of the electromagnet by the second coil L2 and the magnetic force by the first and second fixed permanent magnets 31 and 32. Acts on the 18th side.
[0049]
Therefore, in the S1 pole in the second rotating permanent magnet 22 of the rotor 18, a repulsive force is generated between the second coil L2 side and a tensile force is generated between the first coil L1 side. The N1 pole in the first rotating permanent magnet 21 receives a repulsive force between the first coil L1 side and the N2 pole in the third rotating permanent magnet 23 receives a tensile force between the second coil L2 side. In this way, the rotor 18 rotates counterclockwise in FIG. 3 when a strong magnetic force obtained by adding the magnetic force of the electromagnet and the magnetic force of the fixed permanent magnet acts on the rotating permanent magnet.
[0050]
As shown in FIG. 4A, when the rotation angle of the rotor 18 becomes 30 ° and the central portion of the S1 pole faces the first coil L1, the first coil L1 is not supplied with power, and the second coil L2 continues. Power is supplied, and the third coil L3 is newly supplied. For this reason, the magnetic field lines of the second and third fixed permanent magnets 32 and 33 cannot form a closed circuit passing through the protruding iron core 27 around which the third coil L3 is wound, and the magnetic field lines coming out from the N poles of both magnets are Together with the lines of magnetic force of the electromagnet by the three coils L3, it goes to the rotor 18 side.
[0051]
Therefore, a repulsive force is generated between the N2 pole of the rotor 18 and the third coil L3 side, and a tensile force is generated between the rotor 18 and the second coil L2 side. The S1 pole receives a repulsive force between the second coil L2 side and the S2 pole receives a tensile force between the third coil L3 side. For this reason, the rotor 18 continues to rotate without stopping.
[0052]
Similarly, as shown in FIG. 4B, when the rotation angle of the rotor 18 is 60 ° and the central portion of the N2 pole faces the second coil L2, the second coil L2 is not supplied with power, and the third coil L3 is continuously supplied with power, and the fourth coil L4 is newly supplied. For this reason, the magnetic force obtained by adding the magnetic forces of the third and fourth fixed permanent magnets 33 and 34 and the magnetic force of the fourth coil L4 acts on the rotor 18 side, and the rotor 18 continues to rotate.
[0053]
Similarly, as shown in the graph of FIG. 5, two coils are fed at the same time, and one coil is continuously fed while the rotor 18 rotates 60 °, so that the rotor 18 rotates 30 °. Each time, the first to sixth coils L1 to L6 are sequentially fed. As described above, the rotor 18 is continuously rotated by the strong magnetic force obtained by adding the magnetic forces of the electromagnets by the first to sixth coils L1 to L6 and the magnetic forces of the first to sixth fixed permanent magnets 31 to 36. Is done.
[0054]
Further, when the coils are fed in the order of the first coil L1, the second coil L2, the third coil L3,..., The rotor 51 rotates counterclockwise.
According to this embodiment, the following effects are obtained.
[0055]
(1) In the brushless motor 11, a hybrid magnet is attached to the stator, and the first to fourth rotating permanent magnets 21 to 24 are attached to the rotor 18. For this reason, when the first to sixth coils L1 to L6 are sequentially fed, the rotor 18 is subjected to the strong magnetic force obtained by adding the magnetic forces of the first to sixth fixed permanent magnets 31 to 36 and the magnetic force of the electromagnet. The rotor 18 can be rotated by applying a tensile force and a repulsive force between the first to fourth rotating permanent magnets 21 to 24. Accordingly, it is possible to reduce the size and increase the torque.
[0056]
(2) Since the first to sixth fixed permanent magnets 31 to 36 and the first to sixth coils L1 to L6 are alternately arranged in the circumferential direction, the brushless motor 11 can be made compact in the radial direction.
[0057]
(3) The number of magnetic poles of the rotating permanent magnet of the rotor 18 is four in the circumferential direction, the first to fourth rotating permanent magnets 21 to 24 are arranged adjacent to each other, and six protruding iron cores are formed. For this reason, in the state which can rotate the rotor 51 effectively, it can be set as the simplest and good arrangement | positioning.
[0058]
(4) The first to sixth fixed permanent magnets 31 to 36 are arranged so that their polarities change in the circumferential direction. For this reason, the first to sixth fixed permanent magnets 31 to 36 directly attract the first to fourth rotating permanent magnets 21 to 24 of the rotor 18 in a state where the first to sixth coils L1 to L6 are not supplied with power. The action can be prevented and the possibility of adversely affecting the rotor 18 can be reduced.
[0059]
(5) Since the protruding iron core 27 and the connecting iron core 28 are integrally formed, the magnetic flux easily passes between the protruding iron core 27 and the connecting iron core 28.
(Second Embodiment)
Next, a second embodiment will be described with reference to FIGS. In this embodiment, the rotor is provided with protrusions, and the rotor is not attached with a permanent magnet. The same parts as those in the above embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
[0060]
FIG. 6 is a schematic cross-sectional view of the brushless motor according to the second embodiment, and FIG. 9 is a graph showing the relationship between the rotation angle of the rotor and the power supply state of the coil.
As shown in FIG. 6, the rotor 51 of the brushless motor is made of iron and is formed to have a plurality of radial projections. In this embodiment, the rotor 51 has four protrusions and is formed so that the cross section has a substantially cross shape. As for each protrusion, a protrusion extending to the upper left with respect to the rotation shaft 19 in FIG. The radially outer ends of the protrusions R1 to R4 are formed in an arc shape. Further, no permanent magnet is attached to the rotor 51.
[0061]
The winding direction of the coil is the same as that of the first to sixth coils L1 to L6 of the first embodiment. In this embodiment, the lower left coil in FIG. 6 is referred to as a coil u1, and the coil facing the coil u1 across the rotating shaft 19 is referred to as a coil u2. The winding of the coil u1 and the winding of the coil u2 are connected and constitute the U phase. Also, the coil v1 is the coil adjacent to the coil u2 in the clockwise direction, the coil v2 is the coil facing the coil v2, the coil w1 is the coil adjacent to the coil v2 in the clockwise direction, and the coil is the coil facing the coil Called w2. The coils v1 and v2 and the coils w1 and w2 are also connected to windings, and constitute a V phase and a W phase, respectively. Thus, the coil is formed so as to constitute three phases of U phase, V phase, and W phase.
[0062]
Each protrusion R1-R4 is formed in the same magnitude | size and shape. The circumferential width of each of the protrusions R <b> 1 to R <b> 4 is formed substantially the same as the circumferential width of the connecting iron core 28. Moreover, the width | variety of the circumferential direction of each processus | protrusion R1-R4 is larger than the space | interval between the end surfaces of the circumferential direction of adjacent connection iron cores 28. FIG.
[0063]
In this brushless motor, a rotating light shielding plate is attached so as to rotate integrally with the rotating shaft 19, and a plurality of pairs of photoelectric elements and light sources are arranged via brackets so as to sandwich the rotating light shielding plate. . The rotating light shielding plate is formed with a notch, and the rotational position of the rotor is detected by switching the light receiving state and the light shielding state of the photoelectric element by the rotation of the rotating light shielding plate. The brushless motor is configured such that each of the U-phase to W-phase coils is supplied with power as shown in the graph of FIG. 9 based on the rotational position of the rotor 51 detected by the photoelectric element. In this embodiment, as shown in FIG. 6, when the protrusion R1 of the rotor 51 faces the coil w1, the rotation angle of the rotor 51 is set to 0 °.
[0064]
In the state where the coils of the U-phase to W-phase are not supplied with power, the magnetic lines of force of the first to sixth fixed permanent magnets 31 to 36 are the connection iron core 28, the protruding iron core 27, the yoke, as in the first embodiment. 13 is a closed circuit passing through the cylindrical portion 13a, the magnetic force of each magnet does not act on the rotor 51 side.
[0065]
When the rotation angle θ of the rotor 51 is 0 °, the protrusion R1 of the rotor 51 faces the coil w1, and the protrusion R3 faces the coil w2. Further, the protrusion R2 is opposed to the connecting iron core 28 partially covering the coil u2, and the protrusion R4 is opposed to the connecting iron core 28 partially covering the coil u1. In this state, the U phase, that is, the coil u1 and the coil u2 are supplied with power based on the detection of the rotation angle of the rotor 51 by the photoelectric element.
[0066]
By this power supply, the protrusion R4 is pulled toward the coil u1 by the strong magnetic force obtained by adding the magnetic force of the electromagnet by the coil u1 and the magnetic force of the fourth and fifth fixed permanent magnets 34 and 35. Further, the projection R2 is pulled toward the coil u2 by the strong magnetic force obtained by adding the magnetic force of the electromagnet by the coil u2 and the magnetic force of the first and second fixed permanent magnets 31 and 32. For this reason, the rotor 51 rotates counterclockwise. Further, the lines of magnetic force emerging from the N poles of the coil u1, the fourth and fifth fixed permanent magnets 34, 35 enter the projection R4 through the connection iron core 28, pass through the rotor 51, and pass from the projection R2 to the connection iron core 28. And enters the south pole of the coil u2, the first and second fixed permanent magnets 31 and 32 (see FIG. 7).
[0067]
When the rotation angle θ of the rotor 51 reaches 30 °, the protrusion R4 faces the coil u1, and the protrusion R2 faces the coil u2. Further, a part of the protrusion R3 faces the connection core 28 that covers the coil v1, and a part of the protrusion R1 faces the connection core 28 that covers the coil v2. When the photoelectric element detects that the rotation angle θ is 30 °, the U phase is not supplied with power and a new V phase is supplied.
[0068]
By this power supply, the projection R3 is pulled toward the coil v1 by the magnetic force obtained by adding the magnetic force of the electromagnet by the coil v1 and the magnetic force of the second and third fixed permanent magnets 32 and 33. Further, the projection R1 is pulled toward the coil v2 by the magnetic force obtained by adding the magnetic force of the electromagnet by the coil v2 and the magnetic force of the fifth and sixth fixed permanent magnets 35 and 36. For this reason, the rotor 51 continues to rotate counterclockwise without stopping. In addition, the lines of magnetic force emerging from the north poles of the coil v1, the second and third fixed permanent magnets 32, 33 enter the projection R3 through the connection iron core 28, pass through the rotor 51, and pass from the projection R1 to the connection iron core 28. And enters the south pole of the coil v2, the fifth and sixth fixed permanent magnets 35 and 36 (see FIG. 8A).
[0069]
Similarly, when the rotation angle of the rotor 51 reaches 60 °, the V phase is not supplied with power, the W phase is supplied again, and the rotor 51 continues to rotate counterclockwise. The lines of magnetic force emerging from the north poles of the coil w1, the first and sixth fixed permanent magnets 31 and 36 enter the protrusion R2 through the connection iron core 28, pass through the rotor 51, pass through the connection iron core 28 from the protrusion R4. Then, it enters the south pole of the coil w2, the third and fourth fixed permanent magnets 33 and 34 (see FIG. 8B).
[0070]
When the rotation angle of the rotor 51 reaches 90 °, the W phase is not supplied with power, the U phase is supplied again, and the rotor 51 continues to rotate counterclockwise.
In this way, as shown in the graph of FIG. 9, every time the rotor 51 rotates by 30 °, the power supply of the U, V, and W phases is sequentially switched. Therefore, the rotor 51 is continuously rotated by the strong magnetic force obtained by summing the magnetic forces of the electromagnets by the coils u1 to w2 and the magnetic forces of the first to sixth fixed permanent magnets 31 to 36.
[0071]
According to this embodiment, in addition to the effects (2), (4) and (5) of the above embodiment, the following effects are obtained.
(6) A hybrid magnet provided with a three-phase coil is attached to the stator, and protrusions R1 to R4 are formed on the rotor 51. For this reason, when the coils of the three phases are sequentially fed, the protrusions R1 to R4 are attracted by the strong magnetic force obtained by adding the magnetic forces of the first to sixth fixed permanent magnets 31 to 36 and the magnetic force of the electromagnet. Thus, the rotor 51 can be rotated. Accordingly, even in this case, it is possible to reduce the size and increase the torque.
[0072]
(7) The circumferential width of the protrusions R1 to R4 of the rotor 51 and the circumferential width of the connecting iron core 28 are formed to be approximately the same. For this reason, in the state in which the projections R1 to R4 are most pulled by the electromagnet, the projections R1 to R4 and the connecting iron core 28 face each other in the circumferential direction with almost no excess or deficiency. Therefore, leakage of magnetic flux is reduced between the protrusions R1 to R4 and the connecting iron core 28, and a high torque can be effectively achieved.
[0073]
(8) The circumferential width of the protrusions R <b> 1 to R <b> 4 of the rotor 51 is formed larger than between the circumferential end faces of the adjacent connecting cores 28. For this reason, by allowing the magnetic flux to pass through at least a part of the protrusion and the connecting iron core 28 that face each other, the tensile force can be continuously applied to the rotor 51, and the rotor 51 can be smoothly rotated.
[0074]
(9) Since the number of the protrusions R1 to R4 of the rotor 51 is four, the number of the protrusion cores 27 of the stator is six, and the coils are formed in three phases, the rotor 51 can be effectively rotated. In forming, the simplest and well-arranged configuration can be obtained.
[0075]
(10) The coils u1, v1, and w1 are wound so that the radially inner side is N-pole when power is supplied, and the coils u2, v2, and w2 that face each other are radially inner when supplied with power. Is wound to be the S pole. The rotor 51 is formed so that the protrusions face each other with the rotation shaft 19 in between. For this reason, the magnetic lines of force emanating from the coils u1, v1, and w1 pass through the protrusions R1 and R3 or the protrusions R2 and R4 of the rotor 51 and enter the coils u2, v2, and w2, respectively. Therefore, magnetic flux is easy to pass
In addition, embodiment is not limited to the said embodiment, For example, you may change as follows.
[0076]
The protruding iron core 27 and the connecting iron core 28 are not limited to being integrally formed. For example, the protruding iron core 27 and the connecting iron core 28 are formed separately, and the center portion of the connecting iron core 28 is brought into contact with the tip of the protruding iron core 27. You may make it the structure which carried out.
[0077]
In the first embodiment, the first to fourth rotating permanent magnets 21 to 24 are not limited to being formed adjacent to each other. For example, there is a slight gap between each of the first to fourth rotating permanent magnets. You may form so that it may exist.
[0078]
In the first embodiment, the number of Hall elements 41 is not limited to one, and a plurality of Hall elements 41 may be provided.
The number of coils and fixed permanent magnets is not limited to six each, and may be an even number other than six, for example, two, four, eight, etc.
[0079]
In the first embodiment, the number of fixed permanent magnets attached to the rotor is not limited to four, and may be an even number other than four, for example, two, six, eight, etc. May be.
[0080]
In the second embodiment, the number of protrusions of the rotor is not limited to four, and may be an even number other than 4, for example, 2, 6, 8, or the like.
[0081]
-In 1st Embodiment, a coil is electrically fed in order of 1st coil L1, 2nd coil L2, 3rd coil L3, ..., and is not restricted to rotating the rotor 51 counterclockwise. For example, in the state of θ = 0 °, when power is supplied to the fourth and fifth coils L4 and L5, the radially inner side of the fourth coil L4 becomes the N pole, and the radially inner side of the fifth coil L5 becomes the S pole. Since a tensile force and a repulsive force act between the rotor 18 and the S2 pole, the rotor 18 rotates in the clockwise direction. Next, when it is rotated by 30 °, the power supply to the fifth coil L5 is stopped, the power supply to the fourth coil L4 is continued, and a new power supply is supplied to the third coil L3. Since the repulsive force acts and the tensile force acts between the N2 pole and the fourth coil L4, the rotor 18 continues to rotate clockwise. In this way, the rotor 18 may be rotated in the clockwise direction by supplying power in the order of the sixth coil L6, the fifth coil L5, the fourth coil L4, the third coil L3,.
[0082]
-In 2nd Embodiment, a coil is electrically supplied in order of U phase, V phase, and W phase, and is not restricted to rotating the rotor 51 counterclockwise. For example, when the power is supplied to the V-phase coil in the state of θ = 0 °, the protrusions R2 and R4 are pulled toward the coils v1 and v2, respectively, so that the rotor 51 rotates in the clockwise direction. Next, when the power is supplied in the order of the U phase and the W phase every 30 ° rotation, the rotor 51 continues to rotate in the clockwise direction. For this reason, the rotor 51 may be rotated clockwise by supplying power to the coils in the order of the W phase, the V phase, and the U phase. In this case, if the W phase and the U phase are newly referred to as the U phase and the W phase, respectively, the rotor 51 is rotated in the clockwise direction by supplying power in the order of the U phase, the V phase, and the W phase.
[0083]
In the first and second embodiments, the rotor position may be detected by, for example, a rotary encoder.
In the second embodiment, the position detection of the rotor 51 is not limited to being performed by a combination of the rotating light shielding plate and the photoelectric element. For example, a light source is attached to one of the end frame 14 and the bottom of the yoke 13, and a photoelectric element is attached to the other. When the protrusions R1 to R4 are positioned between the light source and the photoelectric element by the rotation of the rotor 51, the light shielding state is achieved. Thus, the light receiving state is established when the gap between the protrusions R1 to R4 is located. A plurality of sets of light sources and photoelectric elements may be attached so that the position of the rotor 51 can be detected.
[0084]
In the first embodiment, the position detection of the rotor 18 may be configured to detect the position of the rotor 18 by a combination of a rotating light shielding plate and a photoelectric element, for example, as in the second embodiment.
[0085]
In the second embodiment, the rotor 51 is not limited to being made of iron, and may be formed of, for example, another ferromagnetic material.
In the first embodiment, the rotor core 20 is not limited to being made of iron, and may be formed of, for example, another ferromagnetic material.
[0086]
The brushless motor is not limited to the inner rotor type, and may be an outer rotor type, for example.
The technical idea that can be grasped from each of the above embodiments will be described below.
[0087]
(1) In invention of Claim 1 or Claim 2, the said permanent magnet attached to the said rotor is provided adjacent to the circumferential direction.
(2) In the invention according to any one of claims 1, 2 and (1), the protruding iron core and the connecting iron core are integrally formed.
[0088]
(3) In the invention according to any one of claims 3 to 6, the rotor is made of iron.
[0089]
【The invention's effect】
As described in detail above, according to the inventions described in claims 1 to 6, it is possible to reduce the size and increase the torque and to reduce the size in the radial direction.
[Brief description of the drawings]
1A is a schematic cross-sectional view of a brushless motor, and FIG. 1B is a partial cross-sectional schematic side view taken along line IB-IB in FIG.
FIG. 2 is a schematic cross-sectional view showing the operation.
FIG. 3 is a schematic cross-sectional view showing the operation.
FIG. 4 is a schematic cross-sectional view showing the operation.
FIG. 5 is a graph showing a relationship between a rotation angle of a rotor and a power supply state of a coil.
FIG. 6 is a schematic cross-sectional view of a brushless motor according to a second embodiment.
FIG. 7 is a schematic cross-sectional view showing the operation.
FIG. 8 is a schematic cross-sectional view showing the operation.
FIG. 9 is a graph showing the relationship between the rotation angle of the rotor and the power supply state of the coil.
FIG. 10 is a schematic view showing a conventional hybrid magnet.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Brushless motor, 18, 51 ... Rotor, 21-24 ... 1st-4th rotation permanent magnet, R1-R4 ... Projection, 12 ... Motor housing which comprises a stator, 13a ... Cylindrical part which comprises a hybrid magnet, 27 ... similarly protruding iron core, 28 ... same connecting iron core, 31-36 ... same first to sixth fixed permanent magnets, L1-L6 ... same first to sixth coils, u1-w2 ... same coils.

Claims (6)

A plurality of rotors arranged in the circumferential direction so that adjacent magnetic poles are different from each other, and permanent magnets magnetized so that the polarity changes in the radial direction;
A cylindrical portion facing one of the outer peripheral surface and the inner peripheral surface of the rotor, a plurality of fixed iron cores provided in a circumferential direction on a surface of the cylindrical portion facing the rotor, and the rotor wound around the fixed iron core; A brushless motor comprising a coil that is sequentially fed so as to rotate, and a stator having a hybrid magnet that is arranged between the fixed iron cores and a fixed permanent magnet that is arranged so that the polarity changes in the circumferential direction. And
The fixed iron core is formed in a substantially U-shape with a protruding iron core formed so that a base end is connected to the cylindrical portion and a front end protrudes toward the rotor and the coil is wound. And the end part is composed of a connecting iron core facing the cylindrical part,
The end of the connection iron core is magnetically insulated from the cylindrical portion, the fixed permanent magnet is abutted against the adjacent connection iron core at both ends thereof, and the same fixed magnetic pole faces the adjacent fixed permanent magnet. A brushless motor characterized by being arranged as described above. The brushless motor according to claim 1, wherein the number of magnetic poles of the permanent magnet of the rotor is four in the circumferential direction, and the number of the protruding iron cores is six. A rotor having a plurality of radial projections;
A cylindrical portion facing one of the outer peripheral surface and the inner peripheral surface of the rotor, a plurality of fixed iron cores provided in a circumferential direction on a surface of the cylindrical portion facing the rotor, and the rotor wound around the fixed iron core; A brushless motor comprising a coil that is sequentially fed so as to rotate, and a stator having a hybrid magnet that is arranged between the fixed iron cores and a fixed permanent magnet that is arranged so that the polarity changes in the circumferential direction. And
The fixed iron core is formed in a substantially U-shape with a protruding iron core formed so that a base end is connected to the cylindrical portion and a front end protrudes toward the rotor and the coil is wound. And the end part is composed of a connecting iron core facing the cylindrical part,
The end of the connection iron core is magnetically insulated from the cylindrical portion, the fixed permanent magnet is abutted against the adjacent connection iron core at both ends thereof, and the same fixed magnetic pole faces the adjacent fixed permanent magnet. A brushless motor characterized by being arranged as described above. 4. The brushless motor according to claim 3, wherein a circumferential width of the protrusion of the rotor and a circumferential width of the connection core are substantially the same. 5. The brushless motor according to claim 3, wherein a circumferential width of the protrusion of the rotor is larger than a circumferential end surface of the adjacent connecting cores. 6. The number of protrusions of the rotor is four in the circumferential direction, the number of protrusion cores is six, and the coil wound around the protrusion core is a three-phase coil in which the protrusion cores facing each other at 180 ° are fed simultaneously. The brushless motor according to any one of claims 3 to 5, characterized in that:

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