JP2005253280A - Outer rotor type brushless dc motor and ac servo motor having annular stator coil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain cost-effective, small, lightweight, highly efficient outer rotor type brushless DC and AC servo motors by utilizing a winding method having no coil end and the structures of a stator and a rotor. <P>SOLUTION: In three-phase power supply driving, a magnetic circuit is constituted of U-, V-, W-phase coils 10-12 that are wound as split in the axial direction of the stator and arranged in such a way that the ring center of each coil almost corresponds to the center of a rotating shaft 90, inner stator cores 21-23 provided on the inside circumferential side of each coil, and side stator cores 24-29 provided on both end sides in the axial direction. Protruding magnetic pole teeth 30-35 are formed on the outside circumferential side of the side stator cores alternately at positions displaced by π (rad) at an electric angle in the circumferential direction of the rotating shaft sandwiching each coil. Furthermore, the magnetic poles of each coil is stacked in the axial direction by being displaced from each other by 2π/3 (rad) at the electric angle in the circumferential direction of the rotating shaft. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a brushless DC motor and an AC servo motor having an outer rotor type structure, and more particularly to a winding method, a stator core structure, and a permanent magnet type rotor structure.

  Conventionally, as this type of outer rotor type brushless DC motor, a structure as shown in FIG. 17 is generally employed as a spindle motor for a hard disk drive (HDD) or the like. FIG. 17A is an axial half sectional side view, and a U, V, W phase coil 115 is provided on the stator core 125 by a so-called concentrated winding method as shown in FIG. Then, terminal processing such as connection between windings and connection of lead wires is performed.

  In the conventional outer rotor type brushless DC motor as described above, it is necessary to wind the coil 115 so as to be wound around the tooth portion 126 of the stator core 125. Therefore, the winding work is complicated, and further, the fixing is fixed. The length h of the coil end protruding from the axial end face of the core 106 cannot be made zero, and it is difficult to further reduce size, weight, increase efficiency, and reduce costs due to an increase in the winding amount and an increase in copper loss. . In addition, the distributed winding method in which the coils of each phase are distributed in the circumferential direction has a problem such that the length h of the coil end is further increased. The conventional outer rotor type AC servo motor is also used. There was a similar problem.

  The present invention has been made in order to solve the above-described problems, and is an outer rotor type brushless DC motor that can be easily wound, is small, light, and highly efficient, and can reduce cogging torque. The object is to obtain an AC servo motor winding method, a stator core structure, and a rotor structure.

  In order to achieve the above object, the outer rotor type brushless DC motor and the AC servo motor according to the present invention are alternately provided with N and S poles on the inner peripheral side so as to have the same polarity in the axial direction at an equal pitch. A stator having magnetic pole teeth is arranged inside the rotor, and a plurality of coils are wound around the stator in the axial direction, and the center of the ring and the center of the rotating shaft of each coil are wound. Are arranged so that they substantially coincide with each other, and a stator iron core constituting a magnetic circuit is provided on each of the inner peripheral side and the axially opposite ends of each coil, and magnetic pole teeth having the same number of poles as the permanent magnet type rotor are provided on the outer peripheral side. The portions are alternately formed at positions shifted by π (rad) in the circumferential direction of the rotating shaft across the coil, and the magnetic pole teeth of each coil are shifted by a predetermined angle in the circumferential direction of the rotating shaft. Is configured to overlap in the axial direction That.

  In the outer rotor type brushless DC motor and AC servo motor according to the next invention, a plurality of coils are wound in a ring shape divided in the axial direction of the stator, and the center of the ring of each coil and the center of the rotating shaft are approximately The stator cores that constitute the magnetic circuit are provided on the inner peripheral side and the axially opposite end sides of each coil, and magnetic pole teeth with a predetermined number of poles sandwich the coil on the outer peripheral side. Are alternately formed at positions shifted by π (rad) in the circumferential direction of the rotating shaft, and the magnetic pole teeth of each coil are superposed so as to coincide with the axial direction of the rotating shaft. The permanent magnet type rotor that faces the outside of the tooth portion with a predetermined air gap alternately includes N and S poles having the same number of poles as the stator on the inner peripheral side at equal pitches. Predetermined in the circumferential direction of the rotating shaft corresponding to the stator coil Are those constituted by shifting the angle.

  The outer rotor type brushless DC motor and the AC servo motor according to the next invention are further provided with means for reducing leakage of magnetic flux in the stator or the permanent magnet type rotor.

  The outer rotor type brushless DC motor and the AC servo motor according to the next invention are further formed by laminating and integrating at least a part of the stator core using a plate-like magnetic member.

  In the outer rotor type brushless DC motor and AC servo motor according to the next invention, at least a part of the stator core is formed by using a dust core.

  The outer rotor type brushless DC motor and the AC servo motor according to the next invention further include a magnetic pole piece made of a magnetic member on a magnetic pole tooth portion formed on the stator core.

  An outer rotor type brushless DC motor and an AC servo motor according to the next invention are obtained by further skewing a stator or a permanent magnet type rotor.

  In the outer rotor type brushless DC motor and AC servomotor according to the next invention, the stator coil is further formed by using a printed circuit technique.

  In the outer rotor type brushless DC motor and AC servo motor according to the next invention, the stator coil is further formed directly on the surface of the stator core by using a printed circuit technique.

  In the outer rotor type brushless DC motor and the AC servo motor according to the next invention, the stator coil is formed by winding a copper foil into a cylindrical shape and then cutting it into a predetermined width.

  The outer rotor type brushless DC motor and AC servo motor according to the next invention further comprises a plurality of coils for each phase, and the arrangement of the coils in each phase is arranged symmetrically in the axial direction. It is.

  An outer rotor type brushless DC motor and an AC servo motor according to the next invention are formed by integrating the coils of the same phase adjacent to each other in the axial direction and the stator core.

  According to the outer rotor type brushless DC motor and the AC servo motor according to the present invention, the stator is axially divided and wound with a plurality of coils in a ring shape, and the inner peripheral side and the axially opposite ends of each coil. Each of the stator cores that constitute the magnetic circuit is provided, and the magnetic pole teeth are shifted by a predetermined angle in the circumferential direction of the rotating shaft on the outer circumferential side, and are configured to overlap in the axial direction. The coil winding work and terminal processing can be greatly simplified, and since there is no portion corresponding to the coil end, the amount of copper wire used in the coil can be reduced and the copper loss can be reduced. Therefore, the efficiency of the brushless DC motor and the AC servo motor is improved, and it is possible to contribute to the improvement of productivity while realizing cost reduction and reduction in size and weight.

  According to the outer rotor type brushless DC motor and the AC servo motor according to the next invention, the magnetic pole tooth portions of the coils are superposed so as to coincide with the axial direction of the rotating shaft, and the magnetic poles of the permanent magnet type rotor are formed. By shifting the center of each of the stator coils by a predetermined angle in the circumferential direction of the rotating shaft for each opposing stator coil, the die of the stator core can be simplified and the cost can be reduced.

  According to the outer rotor type brushless DC motor and AC servo motor of the next invention, since the means for reducing the leakage of the magnetic flux is provided, the leakage magnetic flux can be reduced and the gap magnetic flux density can be secured. The characteristics of the brushless DC motor and the AC servo motor can be improved.

  According to the outer rotor type brushless DC motor and the AC servo motor according to the next invention, at least a part of the stator core is laminated and integrated using the plate-like magnetic member, so that a high-precision stator is formed. Since the iron core can be easily manufactured at low cost, it can contribute to the improvement of productivity.

  According to the outer rotor type brushless DC motor and the AC servo motor according to the next invention, the magnetic flux can be easily moved three-dimensionally by forming at least a part of the stator core using the dust core. Therefore, the loss inside the iron core can be reduced, and the brushless DC motor and the AC servo motor can be improved in efficiency and contribute to reduction in size and weight.

  According to the outer rotor type brushless DC motor and AC servo motor according to the next invention, the magnetic pole can be effectively utilized by providing the magnetic pole tooth portion with the magnetic pole piece made of a magnetic member. Can be reduced, contributing to the improvement of the characteristics of the brushless DC motor and the AC servo motor.

  According to the outer rotor type brushless DC motor and the AC servo motor according to the next invention, the influence of the harmonic component of the gap magnetic flux can be reduced by skewing the stator or the permanent magnet type rotor. Vibration, noise, and rotation irregularities can be reduced.

  According to the outer rotor type brushless DC motor and AC servo motor according to the next invention, a coil having a high density space factor without using a winding machine by forming a stator coil using printed circuit technology. Can be manufactured at low cost, which can contribute to improvement in productivity and cost reduction.

  According to the outer rotor type brushless DC motor and AC servo motor of the next invention, the stator core and the coil are integrated by forming the stator coil directly on the surface of the stator core by using printed circuit technology. Therefore, it can contribute to miniaturization and productivity improvement.

  According to the outer rotor type brushless DC motor and AC servo motor according to the next invention, the stator coil is formed by cutting the copper foil wound in a cylindrical shape into a predetermined width, thereby having a relatively large current capacity. Since the coil can be manufactured at low cost without using a winding machine, it is possible to contribute to improvement of productivity and cost reduction.

  According to the outer rotor type brushless DC motor and the AC servo motor according to the next invention, a plurality of coils for each phase are provided, and the coils are arranged so that the axial arrangement order of the coils of each phase is symmetrical. -Noise can be further suppressed.

  According to the outer rotor type brushless DC motor and AC servo motor according to the next invention, the coils of the same phase adjacent to each other in the axial direction and the stator core are integrated to contribute to cost reduction and downsizing. can do.

  Embodiments of an outer rotor type brushless DC motor and an AC servomotor according to the present invention will be described below in detail with reference to the accompanying drawings.

  1 to 4 show an example in which the present invention is applied to a three-phase four-pole motor as a first embodiment of an outer rotor type brushless DC motor according to the present invention. The lead wire 13, the stator 20, the permanent magnet type rotor 80, a rotating shaft 90 that supports the rotating frame 93, a bearing member 91, a bracket 92, a detector 94, and the like.

  The U / V / W phase coils 10 to 12 are divided in the axial direction of the rotary shaft 90 and are the same as the rotary shaft 90 so that the center of the ring of the coils 10 to 12 and the center of the rotary shaft 90 substantially coincide with each other. After being wound in the direction, subjected to appropriate insulation treatment and connected in a Y shape, the lead wire 13 is connected to a three-phase power supply unit 16 as shown in FIG.

  The stator 20 is composed of coils 10 to 12, inner stator cores 21 to 23 on the inner peripheral side thereof, and side surface stator cores 24 to 29 on both axial sides of the coils 10 to 12. The U-phase inner stator core 21 and the side stator cores 24 and 25 are magnetically connected to each other. Further, on the outer peripheral side of the side stator cores 24 and 25, convex magnetic poles as shown in FIG. Teeth 30 and 31 are formed respectively. The V and W phases are similarly configured, and magnetic pole tooth portions 32 to 35 are formed on the outer peripheral side.

  The permanent magnet type rotor 80 is processed into a predetermined shape, and the permanent magnets 82 to 84 are connected to the inner peripheral side of the magnetic pole teeth 30 to 35 of the U / V / W phase coils 10 to 12 and a predetermined air gap. Is arranged. The permanent magnets 82 to 84 are formed in a ring shape using a neodymium rare earth magnet or the like, and both the residual magnetic flux and the holding force are large, and the magnetic energy product is extremely large. For this reason, even if the magnet area is reduced, the necessary gap magnetic flux can be secured, and the desired output can be obtained.

  3 (a) to 3 (f) show the configuration of the side stator cores 24 to 29 and the convex magnetic pole tooth portions 30 to 35 formed on the outer peripheral side thereof on the shaft end side (upper part) in FIG. The figure seen through from the opposite axis end side (lower part) is shown, and other components are omitted in the figure. 3A is a side stator core 24 on the shaft end side of the U-phase coil 10, and the magnetic pole tooth portion 30 has its circumferential center aligned with the position of the match mark 36 at 12:00 on the timepiece, It is formed in two places so as to be at the 6 o'clock position of the timepiece shifted by 2π (rad) in electrical angle. FIG. 3B shows a side stator core 25 on the side opposite to the shaft end of the U-phase coil 10, and the magnetic pole tooth portion 31 is formed on the side stator core 24 on the shaft end side at the center in the circumferential direction. It is formed at a position shifted by π (rad) in electrical angle with respect to the center of the magnetic pole tooth portion 30. As a result, through the inner stator core 21 (not shown), the four magnetic poles alternate in the circumferential direction on the outer peripheral side by the magnetic pole teeth 30 and 31 of the side stator cores 24 and 25 across the U-phase coil 10. Formed.

  FIG. 3C shows the side stator core 26 on the shaft end side of the V-phase coil 11, and the magnetic pole tooth portion 32 is centered in the circumferential direction on the side stator core on the shaft end side of the U-phase coil 10. The electrical angle is shifted by 2π / 3 (rad) with respect to the center of the magnetic pole tooth portion 30 formed at 24. FIG. 3D shows the side stator core 27 on the opposite side of the V-phase coil 11, and the magnetic pole teeth 33 are formed in the side stator core 26 on the shaft end side at the center in the circumferential direction. It is formed at a position shifted by π (rad) in electrical angle with respect to the center of the magnetic pole tooth portion 32. As a result, as in the case of the U-phase coil 10, the four-pole magnetic poles pass through the inner stator core 22 (not shown) and the magnetic pole teeth 32 · of the side stator cores 26 and 27 sandwich the V-phase coil 11. 33 are alternately formed in the circumferential direction on the outer peripheral side.

  FIG. 3 (e) shows the side stator core 28 on the shaft end side of the W-phase coil 12, and the magnetic pole tooth portion 34 has a circumferential center in the side stator core on the shaft end side of the U-phase coil 10. The electrical angle is shifted by 4π / 3 (rad) with respect to the center of the magnetic pole tooth portion 30 formed at 24. FIG. 3 (f) shows a side stator core 29 on the opposite side of the W-phase coil 12, and the magnetic pole tooth portion 35 is formed on the side stator core 28 on the shaft end side at the center in the circumferential direction. It is formed at a position shifted by π (rad) in electrical angle with respect to the center of the magnetic pole tooth portion 34. As a result, as in the case of the U / V phase, the four-pole magnetic poles pass through the inner stator core 23 (not shown), and the magnetic pole teeth 34. of the side stator cores 28, 29 sandwich the W-phase coil 12. 35 are alternately formed in the circumferential direction on the outer peripheral side.

  The stator 20 has the above-described positional relationship between the U / V / W-phase coils 10 to 12, the inner circumferential inner stator cores 21 to 23, and the side stator cores 24 to 29 of the coils. It is configured to overlap in the axial direction while maintaining.

  FIG. 4 shows the directions perpendicular to the axes of the permanent magnets 82 to 84 of the permanent magnet type rotor 80 facing the magnetic pole teeth 30 to 35 of the U / V / W phase coils 10 to 12 via a predetermined air gap. A cross section is shown. In each case, four magnetic poles having the same number of poles as the stator are configured to have the same polarity in the axial direction at an equal pitch on the inner peripheral side.

  In this embodiment, for example, the magnetic flux generated by the U-phase coil 10 is generated as follows: inner stator core 21 on the inner peripheral side → side stator core 24 → magnetic pole tooth portion 30 → predetermined air gap → permanent magnet 82 (S pole) ) → permanent magnet 82 (N pole) → predetermined air gap → magnetic pole tooth portion 31 → side surface stator core 25 → inner stator core 21 and a magnetic path that circulates in a three-dimensional manner. The change of the magnetic flux generated in the axial direction can be changed to the change of the magnetic flux in the rotation direction. The magnetic flux generated by the V / W-phase coils 11 and 12 can be similarly actuated, and the magnetic pole teeth 32 and 34 corresponding to the phase difference of the power source are set to 2π / 3 (rad) in electrical direction in the circumferential direction. Since the three-phase power is supplied to the coils 10 to 12 while the polarities of the permanent magnets 82 to 84 are determined by the detector 94, the permanent magnet type rotor 80 is rotated in synchronization with this. A brushless DC motor to be driven can be obtained. Further, by detecting the speed and position of the permanent magnet rotor 80 by the detector 94, it can be operated as an AC servo motor.

  According to the configuration as described above, it is not necessary to wind the coil around the tooth portion of the iron core, and the number of coils in each phase is at least one for each, greatly simplifying coil winding work and terminal processing. be able to. In addition, since there is no portion corresponding to the coil end, reducing the amount of copper wire used in the coil and reducing copper loss can contribute to improving the efficiency of brushless DC motors and AC servo motors. Further miniaturization can be realized. If the winding directions of the coils 10 to 12 are not the same, the corresponding magnetic pole teeth can be operated in the same manner as in the present embodiment by shifting the magnetic teeth by π (rad) in the circumferential direction of the rotating shaft by an electrical angle.

  5 and 6 show a second embodiment of an outer rotor type brushless DC motor according to the present invention. The second embodiment is an example applied to a three-phase four-pole motor as in the first embodiment, and only the configuration of the magnetic pole tooth portions 30 to 35 and the permanent magnet type rotor 80 with respect to the first embodiment. In contrast, FIG. 1 also schematically shows a side view of the axial half-section of the second embodiment.

  FIG. 5 shows the configuration of the side stator cores 24 to 29 in the second embodiment and the convex magnetic pole tooth portions 30 to 35 formed on the outer peripheral side thereof in the same manner as in the first embodiment. The figure seen through from the side (upper part) to the non-axis end side (lower part) is shown, and other components are omitted in the figure. FIG. 5A shows the side stator cores 24, 26, and 28 on the shaft end side of the U, V, and W phase coils 10 to 12 (not shown in the figure). The center in the circumferential direction is formed at two locations so as to be at the 12 o'clock position of the timepiece aligned with the match mark 36 and at the 6 o'clock position of the timepiece shifted by 2π (rad) in electrical angle. FIG. 5B shows the side stator cores 25, 27, and 29 on the side opposite to the end of the coils 10 to 12, and the magnetic pole teeth 31, 33, and 35 are centered in the circumferential direction on the shaft end side. Are formed at positions shifted by π (rad) in electrical angle with respect to the centers of the magnetic pole tooth portions 30, 32, and 34 formed in the side stator cores 24, 26, and 28. As a result, through the inner stator core 21 (not shown), the four magnetic poles alternate in the circumferential direction on the outer peripheral side by the magnetic pole teeth 30 and 31 of the side stator cores 24 and 25 across the U-phase coil 10. Formed. Similarly, the four-pole magnetic poles alternately pass through the inner stator core 22 (not shown) in the circumferential direction on the outer peripheral side by the magnetic pole teeth 32 and 33 of the side stator cores 26 and 27 across the V-phase coil 11. It is formed. Further, the four-pole magnetic poles alternately pass through the inner stator core 23 (not shown in the drawing) in the circumferential direction on the outer peripheral side by the magnetic pole teeth 34 and 35 of the side stator cores 28 and 29 across the W-phase coil 12. It is formed.

  The stator 20 includes the above-described U / V / W-phase coils 10 to 12, the inner peripheral inner stator cores 21 to 23, and the side stator cores 24 to 29 of each coil as described above. The magnetic pole teeth of the coil are overlapped so as to coincide with the axial direction of the rotating shaft.

  6 (a) to 6 (c) show the inside of the permanent magnet type rotor 80 facing the magnetic pole teeth 30 to 35 of the U / V / W phase coils 10 to 12 through a predetermined air gap. A cross section perpendicular to the axis of the permanent magnets 82 to 84 arranged in FIG. In each case, four magnetic poles having the same number of poles as the stator are formed at an equal pitch on the inner peripheral side. 6A shows the permanent magnet 82 facing the magnetic pole teeth 30 and 31 of the U-phase coil 10, and FIG. 6B shows the permanent magnet facing the magnetic pole teeth 32 and 33 of the V-phase coil 11. 83, the center of the magnetic pole in the circumferential direction is deviated by 2π / 3 (rad) in electrical angle with respect to the circumferential center of the magnetic pole of the permanent magnet 82. Further, FIG. The permanent magnet 84 facing the magnetic pole teeth 34 and 35 of the coil 12 is shown. The center of the magnetic pole in the circumferential direction is shifted by 4π / 3 (rad) in electrical angle with respect to the circumferential center of the magnetic pole of the permanent magnet 82. Configured.

  In this embodiment as well, as in the first embodiment, the change in the magnetic flux generated in the axial direction linked to the ring-shaped U / V / W phase coils 10 to 12 is changed to the change in the magnetic flux in the rotation direction. Since the permanent magnets 82 to 84 arranged in the permanent magnet type rotor 80 are shifted by 2π / 3 (rad) in electrical direction in the circumferential direction according to the phase difference of the power source, the three-phase A power-driven brushless DC motor and an AC servo motor can be obtained.

  As described above, this configuration also improves the efficiency of the brushless DC motor and the AC servo motor by simplifying the winding work, reducing the amount of copper wire used in the coil, and reducing the copper loss, as in the first embodiment. The cost can be reduced and further miniaturization can be realized. Moreover, since the die of the stator core can be simplified, it can contribute to the improvement of productivity.

  In the third embodiment, in addition to the configuration of the above-described embodiment, as a means for reducing the leakage of magnetic flux, a magnetic gap is provided between phases adjacent in the axial direction.

  FIG. 7A is a half sectional partial side view in the axial direction showing the vicinity of the stator of the brushless DC motor, and other components are omitted in the drawing. In FIG. 7 (a), the U-phase stator is composed of the coil 10, side stator cores 24 and 25 on both axial ends, and the inner stator core 21, and the V and W-phase stators are the same. It is composed of the coils 11 and 12 and the stator cores, but is adjacent to the U-phase stator core and the V-phase stator core, and between the V-phase stator core and the W-phase stator core. Is provided with a predetermined gap a as a magnetic gap.

  FIG. 7 (b) shows another embodiment. Compared to FIG. 7 (a), the inner stator cores 21, 22, and 23 are integrally formed. Between the side stator core 25 and the V-phase side stator core 26 and between the V-phase side stator core 27 and the W-phase side stator core 28, a predetermined gap a Is provided.

  According to the configuration as described above, by optimizing the dimension a, leakage of magnetic flux to adjacent phases can be reduced, and gap magnetic flux density can be ensured. Therefore, the characteristics of the brushless DC motor and AC servo motor Can be improved. In addition, the stator shown in FIG. 7 has the same characteristics by providing a gap a between the permanent magnets 82 to 84 adjacent to each other in the axial direction of the permanent magnet type rotor combined therewith. The cost can be reduced while reducing the amount of expensive magnets used. Note that the same effect can be obtained even if the gap a is made of a nonmagnetic member without forming a gap.

  8 and 9 show Embodiment 4 of the outer rotor type brushless DC motor and AC servomotor according to the present invention. In the fourth embodiment, as a means for realizing the configuration of the above-described embodiment, a part of the stator core is laminated and integrated using a plate-like magnetic member.

  FIG. 8 shows the stator core of the U-phase coil 10 (omitted in the drawing) through the shaft end side (upper part) of FIG. 1 from the shaft end side (lower part) in the same manner as in Example 1 or Example 2. A view is shown. A convex magnetic pole tooth portion 30 is formed on the side stator core 24 of FIG. 8A, and similarly, a convex magnetic pole tooth portion 31 is formed on the side stator core 25 of FIG. Is formed. FIG. 8B shows the inner stator core 21 that is supported by being sandwiched between the side stator cores 24 and 25.

  Each of the parts shown in FIGS. 8A to 8C is obtained by manufacturing a plate-like magnetic member by press working, and then laminating and fixing the required number of pieces with a crimp 47 using the match mark 36 as a reference. Yes, it can also be fixed by adhesion, caulking pins, screwing, welding, etc. in addition to the caulking. The stator cores of the other coils are configured in the same manner, and each coil is wound after appropriate insulation treatment. In addition, after the stator cores of the phases adjacent in the axial direction are fixed and integrated at the same time, the coils can be wound at the same time.

  FIG. 9A shows a state where the stator core and the coil for one phase are assembled, and FIG. 9B shows a cross section AA of FIG. 9A. A gap having a predetermined width t is provided between the poles formed by the magnetic pole teeth 30 of the side stator core 24 and the magnetic pole teeth 31 of the side stator core 25 serving as the adjacent pole in the circumferential direction. The outer peripheral side shape of the width t and the magnetic pole tooth portions 30 and 31 can be appropriately determined in consideration of the characteristics of the brushless DC motor and the AC servo motor. FIG. 9C shows another embodiment in which the cogging torque is improved by setting the width t = 0 and making the circumferential end faces of the magnetic pole teeth 30 and 31 arcs.

  According to the manufacturing method as described above, a highly accurate stator core can be easily manufactured at low cost, which can contribute to improvement of productivity. At this time, instead of the conventional magnet wire having a circular cross-sectional shape, by using a conductor having a substantially square cross-sectional shape, the gap between the conductors can be reduced and the space factor of the winding can be improved. The temperature rise of the coil can be suppressed, which can contribute to improvement in efficiency and miniaturization of the brushless DC motor and AC servo motor. Note that vibration and noise can be suppressed by using a non-magnetic material such as a resin material in the gap portion of the width t.

  FIG. 10 shows Embodiment 5 of an outer rotor type brushless DC motor and AC servomotor according to the present invention. In Example 5, a part of the stator core is constituted by using a so-called dust core in which iron powder is insulated one by one with an inorganic film and subjected to compression molding or the like.

  FIG. 10A shows a one-phase stator composed of a dust core, and shows the same cross section as FIG. 9B. The stator core is divided into two parts by the dividing surface f and each is composed of a dust core. Further, magnetic pole pieces 40 and 41 are magnetic members on the magnetic pole teeth 30 and 31 of the side stator cores 24 and 25, respectively. They are integrally formed using a certain dust core. The pole piece 40 formed on the side stator core 24 is configured to be shorter than the axial end face of the side stator core 25 by a predetermined dimension b, and the pole piece 41 formed on the side stator core 25 is the same. In addition, it is configured to be shorter than the axial end surface of the side stator core 24 by a predetermined dimension b. In addition, the coil 10 is formed in a ring shape in a separate process and is assembled after an appropriate insulation treatment is performed. The stator cores of the other phases are similarly configured. The stator core divided into two by the dividing surface f is appropriately fixed by adhesion, press fitting, caulking pins, screwing, or the like. FIG. 10 (b) shows a stator for one phase showing another embodiment constituted by a dust core, and shows an example in which the axial core width of the stator is large.

  As shown in Example 1, since the magnetic flux moves three-dimensionally inside the stator core, as described above, by using a dust core having a large specific resistance and permeability in all directions, as described above. The movement of the magnetic flux becomes easy, the loss inside the iron core can be reduced, and it can contribute to the efficiency improvement of the brushless DC motor and the AC servo motor. In addition, since some or all of the core pressing process is not required, the stator core can be easily manufactured at low cost, and the winding of each coil is facilitated, which improves productivity and reduces costs. Can contribute. Furthermore, the magnetic flux can be effectively utilized by the pole piece, and by optimizing the dimension b, the leakage magnetic flux can be reduced and the efficiency can be improved. In addition, a part of the stator core of the phase adjacent in the axial direction can be connected and formed integrally, and the shape of the stator core shown in FIG. 10 can also be configured using a plate-like magnetic member. It is.

  FIG. 11 shows Embodiment 6 of an outer rotor type brushless DC motor and AC servomotor according to the present invention. In the sixth embodiment, in addition to the configuration of the above-described embodiment, the stator is skewed.

  FIG. 11 is a partial view of the outer peripheral surface facing the permanent magnet type rotor, in which the stator core is linearly developed with the rotation axis as the vertical direction. The U-phase magnetic pole tooth portion 30 and the magnetic pole piece 40 are inclined with respect to the magnetic pole tooth portion 31 and the magnetic pole piece 41 adjacent in the circumferential direction by a skew angle, and the case where the gap t = 0 between the poles is shown. Similarly, the magnetic pole teeth and pole pieces of the V and W phases are also inclined by the skew angle. In consideration of the characteristics of the brushless DC motor and the AC servo motor, the magnetic pole tooth portions and the magnetic pole pieces adjacent to each other in the circumferential direction, and the magnetic pole pieces can be connected by a thin bridge portion.

  In the above-described configuration, it is possible to easily skew the stator and optimize the skew angle to reduce the influence of the harmonic component of the gap magnetic flux, and avoid steep fluctuations in the magnetic circuit permeance. Therefore, cogging torque can be reduced, vibration and noise, and thus rotation unevenness can be reduced, and the characteristics of the brushless DC motor and AC servo motor can be improved. Note that the same effect can be obtained by performing skew magnetization or the like on the permanent magnet arranged in the permanent magnet type rotor instead of skewing the stator.

  FIG. 12 shows a seventh embodiment of an outer rotor type brushless DC motor and an AC servomotor according to the present invention. In the seventh embodiment, a stator coil is formed using a printed circuit technique.

  12A is a plan view of the stator coil as viewed from the axial direction, and FIG. 12B is an enlarged view of the cross section BB of FIG. After the conductor layer of the coil 10 is formed in a ring shape by the technique, a protective coating 62 is applied to maintain the electrical insulation and mechanical strength. The dimensions and shape of the conductor layer of the coil 10 are appropriately determined in consideration of the characteristics of the brushless DC motor and the AC servo motor. However, when a large number of turns of the coil 10 is required, the conductor layer configured as described above. Are stacked in the axial direction so that the winding direction of the coil 10 is the same, and connected in series or in parallel using the connection terminals 63 and 64. FIG. 12C shows an example in which a two-layered coil 10 is sandwiched between side stator cores 24 and 25 as a single-phase stator, and shows the same cross section as FIG.

  According to the outer rotor type brushless DC motor and the AC servo motor according to the present invention, it is not necessary to wind the coil around the tooth portion of the iron core. Since a coil having a high density space factor can be manufactured at low cost without using a wire, it is possible to contribute to improvement of productivity and cost reduction.

  FIG. 13 shows Embodiment 8 of an outer rotor type brushless DC motor and AC servomotor according to the present invention. In Example 8, the stator coil is formed directly on the surface of the stator core using a printed circuit technique.

  FIG. 13A is a plan view of the stator coil as seen from the axial direction as in the seventh embodiment, and FIG. 13B shows an enlarged view of the cross section CC of FIG. After an insulating film is formed on the end face in the axial direction of the side stator core 25 provided with the pole piece 41 by the insulating member 61, the conductor layer of the coil 10 is formed in a ring shape by a printed circuit technique, and a protective coating 62 is applied to electrically It is configured to maintain insulation and mechanical strength. As in the seventh embodiment, the size and shape of the conductor layer of the coil 10 are determined as appropriate in consideration of the characteristics of the brushless DC motor and the AC servomotor. The conductor layers configured as described above are stacked in the axial direction so that the winding direction of the coil 10 is the same, and connected in series or in parallel using the connection terminals 63 and 64. FIG. 13C is an example in which side stator cores 24 and 25 each having a two-layered coil 10 as a single-phase stator are overlapped so that the winding direction of the coil 10 is the same. Yes, and shows a cross section similar to FIG.

  As described above, according to the configuration using the printed coil applying the so-called metal substrate technology, the stator core and the coil can be manufactured integrally, so that the brushless DC motor and the AC servo motor can be reduced in size and productivity. It can contribute to improvement. In the case of further downsizing, not only the coil conductor layer but also the magnetic circuit layer constituting the stator core can be formed by using the printed circuit technique.

  FIG. 14 shows a ninth embodiment of an outer rotor type brushless DC motor and an AC servomotor according to the present invention. In Example 9, a copper coil wound in a cylindrical shape is cut to a predetermined width to form a stator coil.

  As shown in FIG. 14 (a), a sheet-like copper foil 65 having an insulating coating on its surface is wound into a cylindrical shape, and conductive pipes 66 and 67 that form connection terminal portions are joined to both ends. Thereafter, the coil 10 is formed by being fixed and integrated with a resin or the like, cut into a predetermined width with a metal wire 68 or the like as shown in FIG. Also in this embodiment, the dimensions and shape of the copper foil forming the coil 10 are appropriately determined in consideration of the characteristics of the brushless DC motor and the AC servo motor. However, when a large number of turns of the coil 10 is required, A plurality of coils configured as described above are overlapped in the axial direction so that the winding direction is the same, and a connection terminal formed by cutting the conductive pipes 66 and 67 between these coils is used. Connections can be made in series or in parallel. FIG. 14C shows an example in which the coil 10 is sandwiched between the side stator cores 24 and 25 as a one-phase stator, and shows the same cross section as FIG.

  As described above, according to the configuration using the so-called slice coil, a coil having a relatively large current capacity can be manufactured at low cost without using a winding machine, so that the productivity of the brushless DC motor and the AC servo motor can be achieved. It can contribute to improvement and cost reduction.

  FIG. 15 shows an embodiment 10 of an outer rotor type brushless DC motor and an AC servomotor according to the present invention. In the tenth embodiment, a plurality of coils for each phase are provided, and the coils are arranged so that the axial arrangement order of the coils for each phase is symmetrical.

  FIG. 15 is a partial sectional side view in the axial direction showing the vicinity of the stator, and other components are omitted in the drawing. In FIG. 15, the number of coils in each phase is two, the U phase coil is composed of 10 and 10a, the V phase coil is composed of 11 and 11a, and the W phase coil is composed of 12 and 12a. ) From the opposite axis end side (lower part) in the arrangement order of U, V, W, W, V, U phase so as to be symmetrical in the axial direction of the rotary shaft 90, After appropriate connection in parallel, the whole is connected in a Y shape as shown in FIG. 2 and connected to the power supply unit 16.

  According to the configuration as described above, it is possible to realize further low vibration and low noise by canceling the vibration generated in the axial direction.

  FIG. 16 shows Embodiment 11 of an outer rotor type brushless DC motor and an AC servomotor according to the present invention. In the eleventh embodiment, the same-phase coils and stator cores that are adjacent to each other in the axial direction in the tenth embodiment are integrated.

  FIG. 16 is a partial half sectional side view in the axial direction showing the vicinity of the stator as in FIG. 15, and other components are omitted in the drawing. In FIG. 16, the W-phase coils 12 and 12a adjacent to each other in the vicinity of the center in the axial direction of FIG. 15 are integrated, and the stator cores of the coils 12 and 12a are also integrated. Then, as shown in FIG. 2, the whole is connected in a Y shape and connected to the power supply unit 16.

  According to the configuration as described above, the manufacture of the stator core and the coil can be simplified, which can contribute to cost reduction and miniaturization.

  In the first to eleventh embodiments, the case where an outer rotor type brushless DC motor and an AC servo motor have four poles and a ring-shaped permanent magnet is applied to the present invention. However, the brushless DC motor and AC according to the present invention are applied to the present invention. The servo motor is also effective for cases having other pole numbers and magnet shapes. The brushless DC motor and the AC servo motor according to the present invention can obtain a smaller and low-cost outer rotor type motor by making the ring-shaped stator coil into a two-phase structure. The less method can also be adopted. In addition, by using a dynamic pressure bearing in the brushless DC motor and AC servo motor according to the present invention, it is possible to realize further small size, light weight, low vibration and low noise.

  The outer rotor type brushless DC motor and the AC servo motor according to the present invention can be used in various industrial fields. Particularly, since the axial dimension can be reduced, the hard disk drive (HDD) and the DV (DVD) ) It can be used as a spindle motor for a drive or the like, or as a CPU cooling fan motor for a personal computer or the like. In addition, since it can be miniaturized, it can be used for robots, micromachines, and the like. Furthermore, the brushless DC motor and the AC servo motor according to the present invention can also obtain electric power as a permanent magnet generator by rotating the rotating shaft by an external force.

FIG. 4 is a half sectional side view in the axial direction of an outer rotor type brushless DC motor according to the first and second embodiments. (The configuration of the side stator core and magnetic pole teeth depends on Fig. 3 or Fig. 5) 1 is a connection diagram of a brushless DC motor in Embodiment 1. FIG. It is the figure which saw through the structure of the side stator iron core and magnetic pole tooth part in Example 1 through the shaft end side (upper part) to the non-shaft end side (lower part). (The salient pole shape is exaggerated) FIG. 3 is a cross-sectional view in a direction perpendicular to the rotation axis of the permanent magnet type rotor in the first embodiment. It is the figure which saw through the structure of the side stator iron core and magnetic pole tooth part in Example 2 through the shaft end side (upper part) to the non-shaft end side (lower part). (The salient pole shape is exaggerated) 6 is a cross-sectional view in a direction perpendicular to the rotation axis of a permanent magnet type rotor in Embodiment 2. FIG. (A) is a stator in Example 3, (b) is an axial direction half cross-section partial side view which respectively shows the stator in another Example. It is the figure which looked at the structure of the stator core in Example 4 through the shaft end side (upper part) from the non-shaft end side (lower part). (A) And (b) is the figure which assembled the stator core in Example 4, (c) is the figure which assembled the stator core in another Example. (A) is an axial cross-sectional side view which shows the stator in Example 5, (b) is an axial cross-sectional side view which shows the stator in another Example. FIG. 10 is a partial view of an outer peripheral surface of a stator core in Example 6. FIG. 10 is a diagram illustrating a configuration of a stator coil in Example 7. FIG. 10 is a diagram showing a configuration of a stator coil in Example 8. FIG. 10 is a diagram showing a configuration of a stator coil in Example 9. FIG. 10 is a partial side view in the axial direction showing a stator in Example 10; FIG. 25 is a partial side view in the axial direction half cross section showing the stator in the eleventh embodiment. The outer-rotor type brushless DC motor of a prior art example is shown, (a) is an axial direction half cross-sectional side view, (b) shows the structure of the principal part.

Explanation of symbols

  10-12 and 10a-12a stator coils, 13 lead wires, 16 three-phase power supply units, 20 stators, 21-23 inner stator cores, 24-29 side stator cores, 30-35 magnetic pole teeth, 36 matches Mark, 40/41 pole piece, 47 crimping position, 61 insulation member, 62 protective coating, 63/64 connection terminal, 65 copper foil, 66/67 conductive pipe, 68 metal wire, 80 permanent magnet rotor 82 to 84 permanent magnets, 90 rotating shafts, 91 bearing members, 92 brackets, 93 rotating frames, 94 detectors, 115 conventional stator coils, 125 conventional stator cores, 126 conventional stator core teeth, a, b, t predetermined gap, f dividing surface, h coil end length,

Claims (12)

A permanent magnet type rotor having alternating N and S poles so as to have the same polarity in the axial direction at an equal pitch is provided on the inner peripheral side, and is opposed to the inside of the rotor via a predetermined air gap. In an outer rotor type brushless DC motor and an AC servo motor in which a stator having a magnetic pole tooth portion is arranged, a plurality of coils are wound in a ring shape on the stator in the axial direction. Arranged so that the center of the ring and the center of the rotating shaft substantially coincide with each other, the stator cores constituting the magnetic circuit are provided on the inner peripheral side and the both axial ends of each coil. And, on the outer peripheral side of the stator core, the magnetic pole tooth portion having the same number of poles as the permanent magnet type rotor is shifted by an electrical angle of π (rad) in the circumferential direction of the rotating shaft across the coil. Further, the outer rotor is configured such that the magnetic pole tooth portions of each coil are shifted by a predetermined angle in the circumferential direction of the rotating shaft and overlapped in the axial direction. Shaped brushless DC motor and AC servo motor. In an outer rotor type brushless DC motor and AC servo motor, a plurality of coils are wound in a ring shape divided in the axial direction of the stator so that the center of the ring of each coil and the center of the rotating shaft substantially coincide with each other. The stator cores constituting the magnetic circuit are provided on the inner peripheral side and the axially opposite ends of each coil. And on the outer peripheral side of the stator core, magnetic pole tooth portions with a predetermined number of poles are alternately formed at positions shifted by π (rad) in electrical direction in the circumferential direction of the rotation axis across the coil, The magnetic pole tooth portion of the coil is configured to overlap with the axial direction of the rotating shaft. Further, the permanent magnet type rotor facing the outside of the magnetic pole tooth portion with a predetermined air gap alternately includes N and S poles having the same number of poles as the stator on the inner peripheral side at equal pitches. An outer rotor type brushless DC motor and an AC servo motor are characterized in that the center in the circumferential direction of the magnetic pole is shifted by a predetermined angle in the circumferential direction of the rotating shaft in correspondence with each coil. 3. The outer rotor type brushless DC motor and the AC servo motor according to claim 1, wherein the stator or the permanent magnet type rotor is provided with means for reducing leakage of magnetic flux. 4. The outer rotor-type brushless DC motor according to claim 1, wherein at least a part of the stator core is formed by laminating and integrating using a plate-like magnetic member. 5. AC servo motor. 5. The outer rotor according to claim 1, wherein at least a part of the stator core is formed by using a so-called dust core (also referred to as an iron core). Shaped brushless DC motor and AC servo motor. 6. The outer rotor type brushless DC motor and the AC servo motor according to claim 1, wherein the magnetic pole tooth portion includes a pole piece made of a magnetic member. 7. The outer rotor type brushless DC motor and AC servo motor according to claim 1, wherein the stator or the permanent magnet type rotor is skewed. The outer rotor type brushless DC motor and the AC servo motor according to claim 1, wherein the coil is formed using a printed circuit technology. The outer rotor type brushless DC motor and the AC servo according to any one of claims 1 to 7, wherein the coil is directly formed on a surface of the stator core using a printed circuit technique. motor. The outer rotor brushless DC motor according to any one of claims 1 to 7, wherein the coil is formed by winding a copper foil into a cylindrical shape and then cutting the coil into a predetermined width. AC servo motor. The outer rotor type brushless according to any one of claims 1 to 10, wherein a plurality of coils of each phase are arranged so that the axial arrangement order of the coils of each phase is symmetrical. DC motor and AC servo motor. 12. The outer rotor type brushless DC motor and AC servo motor according to claim 11, wherein the coils of the same phase adjacent to each other in the axial direction and the stator iron core are integrally formed. Shaped brushless DC motor and AC servo motor.

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