JP2005110372A - Axial gap motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To offer an axial gap motor which is advantageous to avoid the damage of winding and the slack of the winding. <P>SOLUTION: The axial gap motor has a housing 1, a stator 2 fixed to the housing 1, and a rotor 4 retained rotatably in the housing 1. The stator 2 has a plurality of fixed stators 20 which are juxtaposed in the rotational direction and an exciting coil layer 27 which is made by winding a coil 26 on each fixed iron core 20. The rotor 4 has permanent magnets 42 which are juxtaposed in the rotational direction and are arranged so that the polarity of each magnetic pole may alternate in the rotational direction. A gap is made between the axial end face of the stator 2 and the axial end face of the rotor 4. The fixed iron core 20 of the stator 2 is set to be circular in the cross section perpendicular to the axis of the rotor 4. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an axial gap motor having a stator fixed to a housing and a rotor rotatably held in the housing.

  Patent Document 1 discloses an axial gap motor having a stator 200 held in a housing 100 and a rotor 400 rotatably held in the housing 100 as shown in FIGS. 15 and 16. . The stator 200 includes a plurality of fixed iron cores 210 arranged in parallel along the rotation direction, and an exciting coil layer 230 formed by winding the windings 220 around the fixed iron cores 210. As can be understood from FIG. 16, the stator core 210 is formed by assembling a set of two laminated bodies 211 in which a plurality of iron plates 212 having a T-shaped cross section are laminated so as to face each other. The laminated body 211 constituting the fixed iron core 210 has a T shape. The exciting coil layer 230 is formed by winding the winding 220 around the fixed iron core 210 formed by assembling such a set of two laminated bodies 211.

  Further, as shown in FIGS. 17 and 18, Patent Document 2 includes a stator 600 provided on a printed wiring board 500 and a rotor 700 rotatably attached to the printed wiring board 500 via a bearing 511. Axial gap motors are known. 17 and 18, the stator 600 has a short cylindrical portion 610 and a flange portion 620 that are short in the axial length direction. It is inferred that the stator 600 is formed of a forged press-formed product.

  Patent Document 3 discloses a magnetic circuit structure of a rotating machine in which a stator having an iron core with a square cross section is used and a winding is wound around the iron core with a square cross section to form an exciting coil layer. Similarly, Patent Document 4 also discloses a rotating machine that uses a stator having an iron core with an angular cross section and winds a winding around the iron core with an angular cross section to form an exciting coil layer.

  Further, in Patent Document 5, a soft magnetic powder obtained by coating soft magnetic metal particles with a nonmagnetic metal oxide by mechanofusion and further coating a high resistance soft magnetic material with mechanofusion is used. A composite soft magnetic material is disclosed in which an aggregate is pressed and sintered with a hot press or the like.

  In Patent Document 6, a soft magnetic powder in which a surface of soft magnetic metal particles is coated with a high-resistance substance and a phosphoric acid-based chemical conversion coating is laminated thereon is used. A compression-molded soft magnetic molded body is disclosed.

  Patent Document 7 discloses a high-frequency dust core obtained by compression-molding an aggregate of soft magnetic powders coated with a glassy insulating layer containing P, Mg, B, and Fe as essential elements on the surface of soft magnetic metal particles. Has been.

Patent Document 8 discloses a soft magnetic molded body for a motor in which an aggregate of soft magnetic powders having a ferrite layer coated on the surface of soft magnetic iron powder containing iron as a main component is compression molded.
JP 2000-253635 A Japanese Utility Model Publication No. 6-070476 JP-A-9-121521 Japanese Patent Laid-Open No. 10-23697 JP-A-5-109520 Japanese Patent Laid-Open No. 2001-85211 JP-A-6-260319 JP 2003-86415 A

  According to the above-described axial gap motor according to Patent Document 1, as shown in FIGS. 15 and 16, the winding 220 is attached to the fixed iron core 210 formed by laminating a plurality of iron plates 212 having a T-shaped cross section. Since the exciting coil layer 230 is formed by winding, the winding 220 may be damaged by the edge of the corner edge 215 of the fixed iron core 210. In particular, if the winding 220 is tightly wound so that the winding 220 does not loosen, the risk of the winding 220 being damaged by the edge of the corner edge 215 increases. Further, since the exciting coil layer 230 is formed by winding the winding 220 around the fixed iron core 210 having a square shape in cross section, there is a limit in increasing the occupation ratio of the winding 220 of the exciting coil layer 230, and consequently the motor. There are limits to increasing efficiency.

  According to the above-described axial gap motor according to Patent Document 2, as shown in FIG. 18, the stator 600 has a short cylindrical portion 610 and a flange portion 620 that are short in the axial length direction. In addition, since the exciting coil layer 800 is formed by winding the winding 820 around the short cylindrical portion 610 having a short axial length in the stator 700 provided on the printed wiring board 500, it is difficult to wind the winding 820. There was a bug. In particular, since the printed wiring board 500 is thin and rich in flexibility, the printed wiring board 500 is bent by a load or the like when the winding 820 is wound around the short cylinder portion 610, and the short cylinder portion 610 and the flange portion 620 are deformed. May be displaced. In this case, the winding 820 may touch the edge of the flange 620 and damage the winding 820. Furthermore, since the printed wiring board 500 is thin and rich in flexibility, an unexpected force may act on the winding 820 wound around the short cylindrical portion 610, and the winding of the winding 820 may be loosened. .

  Furthermore, according to the motor according to Patent Document 3 and the motor according to Patent Document 4, an exciting coil layer is formed by winding a winding around an iron core having an angular cross section using a stator having an iron core having an angular cross section. Therefore, the winding may be damaged by the edge of the corner edge portion of the fixed iron core. Furthermore, since the exciting coil layer is formed by winding a winding around a square iron core in cross section, there is a limit to increasing the occupancy ratio of the winding of the exciting coil layer, and in turn, limiting the motor efficiency. There is.

  Patent Documents 5 and after do not disclose a technique for forming an exciting coil layer by winding a winding around a stator core having a circular cross section.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an axial gap motor that is advantageous in avoiding damage to windings and loosening of windings.

An axial gap motor according to aspect 1 includes a housing,
A stator having a plurality of fixed iron cores fixed to the housing and arranged in parallel along the rotation direction, and an exciting coil layer formed by winding a winding around each of the fixed iron cores;
A rotor having permanent magnets that are rotatably held in the housing so as to face the stator in the axial direction, and are arranged in parallel along the rotation direction so that the polarities of the magnetic poles alternate along the rotation direction. And
In an axial gap motor that forms a gap between the shaft end surface of the stator and the shaft end surface of the rotor,
The stator core of the stator is characterized by being set to have a circular cross section in a cross section along the direction perpendicular to the axis of the rotor.

  According to the axial gap motor according to aspect 1, the fixed iron core of the stator is set to have a circular cross section in a cross section along the direction perpendicular to the axis of the rotor. For this reason, when the winding is wound around the fixed iron core, contact between the winding and the edge is avoided, damage to the winding is suppressed, and durability of the stator can be improved. Furthermore, the operability of winding the winding around the fixed iron core is improved.

  According to the axial gap motor according to aspect 2, the side of the fixed iron core that faces the permanent magnet of the rotor has a protrusion that extends outward in the radial direction of the fixed iron core, and the protrusion is a shaft of the fixed iron core. It is the flange part extended in the ring shape along the circumference of a core, It is characterized by the above-mentioned. By the flange portion of the fixed iron core, it is possible to suppress the excitation coil layer wound around the fixed iron core from being detached from the fixed iron core.

  According to the axial gap motor according to aspect 3, the flange portion of the fixed iron core has an inclined surface whose outer diameter becomes smaller toward the rotor in a cross section along the axis of the rotor. In this case, it is advantageous to direct the magnetic flux generated on the stator side by the exciting coil layer toward the central region of the magnetic pole of the permanent magnet of the rotor. For this reason, the magnetic flux can be efficiently transmitted to the central region of the magnetic pole of the permanent magnet, which is advantageous in improving motor efficiency and suppressing coking torque, which is pulsating torque.

  According to the axial gap motor of aspect 4, the fixed iron core is formed by consolidating an aggregate of soft magnetic particles having an insulating coating layer having high electrical insulation. In this case, the insulating coating layer can increase the specific resistance of the fixed core, thereby reducing loss such as eddy current loss of the fixed core while ensuring the permeability of the fixed core.

  According to the axial gap motor according to aspect 5, the rotor has a yoke that is rotatable and a permanent magnet that is held by the yoke, and the yoke has a soft magnetic property having an insulating coating layer having high electrical insulation. It is characterized by being formed by consolidating an aggregate of particles. In this case, the insulating coating layer can increase the specific resistance of the yoke, thereby reducing the loss of the eddy current loss of the yoke while ensuring the magnetic permeability of the yoke.

  Examples of the insulating coating layer of the soft magnetic particles constituting the fixed iron core and / or the yoke include a ferrite containing iron oxide as a main component or a phosphorylation conversion film containing a phosphate as a main component. it can. Examples of the ferrite include a form containing one or more of iron, nickel, cobalt, manganese, copper, zinc, rare earth elements and the like. Furthermore, examples of the insulating coating layer of the soft magnetic particles include a resin coating layer such as polyamide and polyimide. Iron-based powder particles can be used as the soft magnetic particles. Examples of the iron-based powder particles include pure iron or those having a composition close to pure iron. When compacting an aggregate of soft magnetic particles, if the amount of carbon and silicon is large, the soft magnetic particles become too hard, and when the aggregate of soft magnetic particles is molded, There is a limit to improving compression moldability. Therefore, when the soft magnetic particles not coated with the insulating coating layer are defined as 100%, carbon can be exemplified by 0.1% or less, 0.01% or less, or 0.005% or less in terms of weight ratio, 0.05% or less or 0.01% or less can be exemplified, and silicon can be exemplified by 0.2% or less, 0.1% or less, or 0.05% or less. In this case, it is possible to prevent the soft magnetic particles from becoming too hard, and when compressing the aggregate of soft magnetic particles, it is possible to contribute to improving the compression moldability of the aggregate of soft magnetic particles. However, depending on the case, the amount of carbon and silicon in the iron-based powder particles may be in a form exceeding the above-described values.

  Examples of the average particle diameter of the soft magnetic particles include 10 to 500 micrometers, 20 to 120 micrometers, and 30 to 100 micrometers, but are not limited thereto. Although the thickness of the insulating coating layer depends on the use of the motor and the particle size of the soft magnetic particles, it can be exemplified by 10 to 20 micrometers and 50 to 20 micrometers, but is not limited thereto.

  In the axial gap motor according to aspect 6, assuming that the thickness of the permanent magnet is t1, and the thickness of the yoke portion that does not hold the permanent magnet is t2, the range of t2 / t1 = 1.5 to 4.0. It is characterized by being set to. In this case, the thickness of the yoke portion that does not hold the permanent magnet in the yoke is secured, and the rigidity of the yoke portion is secured. Therefore, it is possible to prevent the yoke from being bent and deformed by a magnetic attraction force and a magnetic repulsive force between the fixed iron core and the permanent magnet generated during the rotation of the motor. Although t2 / t1 can be selected according to the type of the axial gap motor, the upper limit of t2 / t1 is, for example, 3.5, 3.0, 2.8, 2.5, or 2.0. The lower limit that can be combined with this upper limit is, for example, 1.6, 1.7, or 1.8.

  In particular, when the yoke is formed by consolidating an aggregate of soft magnetic particles having an insulating coating layer having high electrical insulation, even if the yoke is thick, eddy current loss in the yoke Loss can be suppressed. For this reason, the yoke can be thickened and the rigidity thereof can be increased. Therefore, even when the magnetic attractive force and the magnetic repulsive force between the fixed iron core and the permanent magnet generated during the rotation of the motor are large, the yoke can be deformed and deformed by the magnetic attractive force and the magnetic repulsive force. This is advantageous for ensuring high performance and high reliability of the motor.

  According to the axial gap motor according to aspect 7, the insulating coating layer of the soft magnetic particles forming the yoke is set to be thinner than the insulating coating layer of the soft magnetic particles forming the fixed iron core. To do. Since the fixed iron core is fixed to the housing, no centrifugal force acts on the fixed iron core even when the motor is driven to rotate. On the other hand, since the rotor rotates when the motor is driven to rotate, centrifugal force acts on the yoke of the rotor. For this reason, when the centrifugal force generated by the rotation is large, the yoke is preferably strong.

  In consideration of this point, the soft magnetic particles forming the fixed iron core and the soft magnetic particles forming the yoke can be made different. Therefore, the thickness of the insulating coating layer of the soft magnetic particles forming the yoke can be set thinner than the thickness of the insulating coating layer of the soft magnetic particles forming the fixed iron core. In this case, it is advantageous for securing the strength of the yoke while increasing the specific resistance in the yoke and reducing the loss such as eddy current loss in the yoke.

  According to the axial gap motor of the present invention, the stator core of the stator is set to have a circular cross section in the cross section along the direction perpendicular to the axis of the rotor. Therefore, when the winding is wound around the stator core of the stator to form the exciting coil layer, the contact between the edge of the stator core and the winding can be avoided, and thus the possibility of damaging the winding can be reduced. Furthermore, since the stator is fixed to the housing, the fixing property to the exciting coil layer is improved. Therefore, even when an external force acts on the housing, it is possible to prevent the windings constituting the exciting coil layer from being loosened.

Embodiment 1

  Hereinafter, Embodiment 1 of the present invention will be specifically described with reference to FIGS. The axial gap motor according to the present embodiment is a brushless motor. As shown in FIG. 1, this axial gap motor includes a housing 1, a stator 2 fixed to the housing 1, and a set of two rotors rotatably held in the housing 1 around an axis P. 4 is provided. A gap 15 and a gap 16 are formed between the shaft end surface of the stator 2 and the shaft end surface of the rotor 4. The gaps 15 and 16 are formed on both sides of the stator 2 in the axial direction of the motor.

  As shown in FIG. 1, the housing 1 includes a first housing 11 having a cylindrical shape having an opening 10, and a second housing 12 having a plate shape connected to the opening 10 of the first housing 11 and connected thereto. Is formed. The bearing holder 11 a of the first housing 11 holds the bearing 13. The bearing holder 12 a of the second housing 12 holds the bearing 14. The bearings 13 and 14 are held by the housing 1 via a stop ring 40n.

  It is preferable that the first housing 11 and the second housing 12 have a property that it is difficult to transmit magnetic flux and a property that it is difficult for eddy current to flow. Therefore, the first housing 11 and the second housing 12 can be formed of bakelite, resin, or the like. However, depending on the case, it can be formed of stainless steel or aluminum alloy.

  The stator 2 is fixed to the inner peripheral surface 11 i of the first housing 11 of the housing 1 by an adhesive. The rotor 4 is rotatably held by the housing 1 via bearings 13 and 14. The rotor 4 is provided as a set of two so as to face the axial end surfaces of the stator 2 facing away from each other in the direction in which the axis P extends. A stator 2 is arranged between a set of two rotors 4.

  FIG. 2 shows an end view of the stator 2. As shown in FIG. 2, the stator 2 includes a plurality of fixed iron cores 20 arranged in parallel around the axis P of the rotor 4 along the rotation direction (arrow R direction) of the rotor 4 at intervals. An excitation coil layer 27 formed by winding multiple windings 26 around the outer peripheral surface of each fixed iron core 20, a stator covering layer 28 covering the excitation coil layer 27 and the fixed iron core 20, and a stator covering layer 28. It has a shaft insertion hole 29 formed in the central area. The winding 26 is formed of a conductive wire and a conductive wire coating layer coated on the conductive wire. The stator covering layer 28 covers the outer peripheral surface of the exciting coil layer 27. The stator coating layer 28 may be formed by injection molding or compression molding. The stator coating layer 28 is formed using a resin as a base material, but may be formed of non-metal bakelite. As shown in FIG. 2, a plurality (six) of the fixed iron cores 20 are arranged in parallel at intervals of 60 degrees in the rotation direction (arrow R direction).

  As shown in FIG. 1, the rotor 4 includes a rotating shaft 40 (material: steel for machine structure) having an axis P, a disk-shaped soft magnet 41 held on the rotating shaft 40, and a yoke 41 and a permanent magnet 42 having a disk shape held by 41. As shown in FIG. 1, the yoke 41 is fixed to the outer peripheral side of the large-diameter portion 40 a of the rotating shaft 40 while being restrained by the stop ring 40 m in a state where the yoke 41 is in contact with the outer peripheral surface of the rotating shaft 40. ing. The shaft end surfaces 42a and 42b of the permanent magnet 42 are magnetic poles. The permanent magnet 42 is a neodymium-iron-boron system, but is not limited to this, may be a samarium-cobalt system, and may be a ferrite magnet in some cases.

  A resistance wall 41 r (see FIG. 1) that provides resistance to the centrifugal force acting on the permanent magnet 42 when the centrifugal force acts on the permanent magnet 42 as the motor rotates is provided in the outer peripheral area of the yoke 41. The resistance wall 41 r is provided outside the permanent magnet 42. Furthermore, a resistance wall 41 w (see FIG. 1) that provides resistance against the displacement of the permanent magnet 42 is provided in the inner peripheral area of the yoke 41. The resistance wall 41 w is provided on the outer peripheral side of the permanent magnet 42.

  FIG. 3 shows an end view of the rotor 4. As shown in FIG. 3, a plurality (eight) of permanent magnets 42 of the rotor 4 are arranged in parallel along the rotation direction (arrow R direction) at intervals, and the polarity of the magnetic poles is set in the rotation direction (arrows). (Along the R direction). The number of permanent magnets 42 and the number of fixed iron cores 20 are different values.

  FIG. 4 is a perspective view of the fixed iron core 20 which is the main element of the stator 2. FIG. 5 shows a cross section of the fixed iron core 20 around which the exciting coil layer 27 cut along the direction perpendicular to the axis of the rotor 4 is wound. As shown in FIG. 5, the fixed iron core 20 of the stator 2 is set to have a circular cross section.

  As shown in FIG. 6, the fixed iron core 20 is set to have a circular cross section, and the outer peripheral surface 21 c is formed of a cylindrical main body portion 21 and a ring-shaped flange portion 23 that is a protrusion. . The flange portion 23 is formed so as to face each other on both the one shaft end and the other shaft end of the main body portion 21 of the fixed iron core 20. The flange portion 23 extends coaxially with the main body portion 21 of the fixed iron core 20 in the radially outward direction, and extends in a ring shape around the axis P <b> 2 of the fixed iron core 20. The flange portion 23 has a flat shaft end surface 23 f that can face the permanent magnet 42 of the rotor 4.

  When the motor is used, power is supplied to the exciting coil layer 27 and a rotating magnetic field is generated by the fixed iron core 20. The rotor 4 rotates about its axis P relative to the stator 2 by the magnetic attraction force and / or magnetic repulsion force generated by the rotating magnetic field by the fixed iron core 20 and the magnetic field of the permanent magnet 42.

  FIG. 7 shows a state in which the permanent magnet 42 of the rotating rotor 4 approaches the fixed stator 2. As shown in FIG. 7, since the fixed iron core 20 is formed with a flange portion 23 protruding outward in the radial direction thereof, it is advantageous to take in the magnetic flux passing through the permanent magnet 42 and the fixed iron core 20 at an early stage. It is advantageous for improving the motor efficiency and suppressing the coking torque which is a pulsating torque. Therefore, the flange part 23 of the fixed iron core 20 can function as a magnetic flux taking part.

  FIG. 6 shows a cross section along the axis of the rotor 4. As shown in FIG. 6, the flange portion 23 of the fixed iron core 20 has an inclined surface 24 having a conical surface shape whose outer diameter decreases toward the rotor 4. Here, the flange portion 23 of the fixed iron core 20 has higher magnetic permeability than the fixed iron core coating layer 28. For this reason, when the exciting coil layer 27 is fed to form a rotating magnetic field in the fixed iron core 20, the magnetic flux generated in the exciting coil layer 27 is more transparent than the fixed iron core coating layer 28 made of a resin having a low permeability. This is advantageous for transmitting the inside of the flange portion 23 along the inclined surface 24 having a high magnetic permeability. Therefore, it is advantageous to direct the magnetic flux toward the center line P3 (magnetic pole center) of the permanent magnet 42 of the rotor 4. Therefore, the magnetic flux can be efficiently transmitted to the central region where the magnetic field is strong among the magnetic poles of the permanent magnet 42, which is advantageous for improving the motor efficiency and suppressing the coking torque which is a pulsating torque.

  As shown in FIG. 6, assuming that the outer peripheral end 24 p on the side with the larger outer diameter is the outer peripheral end 24 p on the side with the larger outer diameter, the outer peripheral end 24 p in the radial direction is the outer peripheral end 24 p on the side with the smaller outer diameter. The outer peripheral edge 42p of the permanent magnet 42 is located between the end 24p and the inner peripheral end 24. In this case, a magnetic flux capturing function by the flange portion 23 of the fixed iron core 20 is ensured.

  Furthermore, according to the present embodiment, as described above, the inclined surface 24 of the flange portion 23 of the fixed iron core 20 has a conical surface shape whose outer diameter decreases toward the rotor 4 (see FIG. 6). This is advantageous in increasing the surface area of the inclined surface 24 that can function as an engagement surface. As a result, the joining area of the inclined surface 24 of the flange part 23 of the fixed iron core 20 and the engaging surface 28c of the stator coating layer 28 can be increased. Thereby, the integrity of the fixed iron core 20 and the stator coating layer 28 can be further enhanced.

  Further, since the inclined surface 24 of the flange portion 23 of the fixed iron core 20 is inclined so that the outer diameter becomes smaller toward the rotor 4, the retaining property to the fixed iron core 20 is improved, and the stator covering layer 28 is improved. It is also advantageous to prevent the fixed iron core 20 from coming off.

  According to the present embodiment, as shown in FIG. 8, the soft magnetic particles 5 formed by coating the surface of the iron-based powder particles 51 with the insulating coating layer 50 having high electrical insulation are used. The iron-based powder particles 51 have an average particle size of about 60 to 120 μm (particularly 80 μm), are water atomized powder particles, and have a purity of 99.95% or more by weight ratio. Thus, the iron-based powder particles 51 have a composition close to that of pure iron. Specifically, when the iron-based powder particles 51 not coated with the insulating coating layer 50 are defined as 100%, carbon is 0.002% or less, oxygen is 0.01% or less, and silicon is 0.01%. % Or less. Thereby, the compression moldability of the soft magnetic particles 5 is ensured. The insulating coating layer 50 is a film subjected to phosphorylation conversion treatment, and has a thickness of 50 to 500 nanometers, particularly 100 to 300 nanometers, but is not limited thereto.

The fixed iron core 20 is formed by solidifying the aggregate of the soft magnetic particles 5 having the insulating coating layer 50 as described above. Specifically, the fixed iron core 20 is formed by loading the soft magnetic particles 5 having the insulating coating layer 50 as described above into a cavity of a molding die and performing warm compacting. The above-mentioned warm compacting conditions are 120 to 170 ° C., particularly 150 ° C. in the atmosphere, and the molding pressure is 5000 to 12000 kgf / cm ² (≈490 to 1176 MPa), especially 9000 kgf / cm ^2. (≈882 MPa). Thus, although the fixed iron core 20 is formed by warm compression molding, it is an unsintered product.

  As described above, since the fixed iron core 20 is formed using the soft magnetic particles 5 having the insulating coating layer 50 as a raw material, the specific resistance of the fixed iron core 20 can be increased. In general, it is said that the eddy current loss is basically inversely proportional to the specific resistance. For this reason, if the specific resistance of the fixed core 20 is increased, loss such as eddy current loss of the fixed core 20 can be reduced while increasing the magnetic permeability of the fixed core 20. FIG. 9 schematically shows a state in which the soft magnetic particles 5 having the insulating coating layer 50 are consolidated. The insulating coating layer 50 exists like a grain boundary, which is advantageous for reducing the eddy current loop and reducing the eddy current loss.

  According to the present embodiment, not only the fixed iron core 20 but also the yoke 41 of the rotor 4 is formed by consolidating the aggregate of the soft magnetic particles 5 having the insulating coating layer 50 having high electrical insulation. . For this reason, the insulation coating layer 50 can increase the specific resistance of the yoke 41, and the loss of the yoke 41 such as eddy current loss can be reduced while the magnetic permeability of the yoke 41 is ensured. Specifically, the soft magnetic particles 5 having such an insulating coating layer 50 are loaded together with the permanent magnet 42 into a cavity of a mold (not shown) and warm compacted to form the yoke of the rotor 4. 41 is formed. The conditions for warm compacting are basically the same as those for the fixed iron core 20. Therefore, although the yoke 41 is formed by warm compression molding, it is an unsintered product.

  According to the present embodiment, regarding the rotor 4, when the thickness of the permanent magnet 42 is t1 (see FIG. 6) and the yoke 41 portion of the yoke 41 that does not hold the permanent magnet 42 is t2 (see FIG. 6). T2 / t1 = 1.5 to 4.0, particularly 1.8 to 2.2, and the yoke 41 is thickened.

  During the rotation of the motor, a magnetic attractive force and a magnetic repulsive force are generated between the rotating magnetic field of the fixed iron core 20 and the magnetic field of the permanent magnet 42. When the rotating magnetic field by the fixed iron core 20 and the magnetic field of the permanent magnet 42 are strong in order to improve the performance of the motor, the magnetic attractive force and the magnetic repulsive force are inevitably increased during the rotation of the motor, and the yoke 41 moves in the directions of arrows A1 and A2. There is a possibility that the gap width of the gaps 15 and 16 may be changed by microscopically bending and deforming along (see FIG. 6). In this case, it is not preferable to obtain high performance and high reliability of the motor.

  In this respect, according to the present embodiment, the yoke 41 is formed by consolidating the aggregate of the soft magnetic particles 5 described above. Therefore, even if the thickness t2 of the yoke 41 is increased, the eddy current of the yoke 41 is increased. Loss such as loss can be reduced. Thus, since the loss of the yoke 41 can be reduced, the thickness of the yoke 41 can be secured and the rigidity of the yoke 41 can be increased. Therefore, even when the magnetic attractive force and the magnetic repulsive force are large during the rotation of the motor, it is possible to suppress the yoke 41 from being microscopically bent and deformed by the magnetic attractive force and the magnetic repulsive force, thereby increasing the mechanical loss. Can be reduced, and the reliability of the motor can be further enhanced.

  According to the present embodiment, the thickness of the insulating coating layer 50 of the soft magnetic particles 5 forming the yoke 41 is t4, and the thickness of the insulating coating layer 50 of the soft magnetic particles 5 forming the fixed iron core 20 is t5. At this time, t4 = t5 may be set, t4≈t5 may be set, t4> t5 may be set, or t4 <t5 may be set.

  According to this embodiment, the thickness of the iron-based powder particles 51 of the soft magnetic particles 5 forming the yoke 41 is t6, and the thickness of the iron-based powder particles 51 of the soft magnetic particles 5 forming the fixed iron core 20 is t7. In this case, t6 = t7 may be set, t6≈t7 may be set, t6> t7 may be set, or t6 <t7 may be set.

Embodiment 2

10 and 11 show the second embodiment. FIG. 10 shows a cross-sectional view of the stator 2 according to the second embodiment. FIG. 11 is a cross-sectional view of the stator 2 taken along line XI-XI in FIG.
The present embodiment has basically the same configuration as that of the first embodiment, and basically has the same functions and effects. Hereinafter, a description will be given centering on portions different from the first embodiment. Parts having common functions are denoted by the same reference numerals as much as possible. The stator 2 is integrated by an insert molding method. Specifically, the fixed iron core 20 on which the winding 26 is wound and the exciting coil layer 27 is disposed is disposed at a predetermined portion of a molding cavity of a molding die (not shown), and resin is loaded into the molding cavity and solidified. Thus, the resin is molded and integrated. As a result, the fixed iron core 20, the exciting coil layer 27, and the stator coating layer 28 are integrally formed. As a result, the fixed iron core 20 can be assembled and bonded to the housing 1 at a time, and the manufacturing process can be shortened. Furthermore, by forming the fixed iron core 20 at the same time, it is possible to improve the positional accuracy of the fixed iron core 20 and to suppress loosening and displacement, and to improve the reliability of the motor.

  In FIG. 11, the stator covering layer 28 is shown as dots in order to avoid complication of the drawing. According to the second embodiment described above, the fixed iron core 20 of the stator 2 is set to have a circular cross section in the cross section along the direction perpendicular to the axis P of the axis 4 of the rotor 4. The outer peripheral surface of 21 does not have an edge, and contact between the winding and the edge can be avoided. Therefore, when winding the winding 26 around the fixed iron core 20, the risk of damaging the winding 26 can be reduced. Further, since the stator 2 is fixed to the housing 1, the fixing property to the exciting coil layer 27 is improved, and the winding 26 constituting the exciting coil layer 27 is loosened even when an external force is applied to the housing 1. This can be prevented.

Embodiment 3

  12 and 13 show the third embodiment. The present embodiment has basically the same configuration as that of the first embodiment, and basically has the same functions and effects. Parts having common functions are denoted by the same reference numerals as much as possible. Hereinafter, a description will be given centering on portions different from the first embodiment. A thrust bearing 70 is interposed between the shaft end surface of the stator 2 and the shaft end surface of the rotor 4. The thrust bearing 70 is disposed radially outward from the outer peripheral surface of the large-diameter portion 40a of the rotary shaft 40. The thrust bearing 70 includes a first metal ring 71 that engages with the shaft end surface of the stator 2, a second metal ring 72 that engages with the shaft end surface of the yoke 41 of the rotor 4, and the first ring 71. And a plurality of ball-shaped metal rolling elements 73 provided between the second ring 72 and the second ring 72. The thrust bearing 70 is provided coaxially on the outer peripheral side of the rotary shaft 40 and has a function of maintaining a constant gap width between the gaps 15 and 16 between the shaft end surface of the stator 2 and the shaft end surface of the rotor 4. It can function as a regulating member having

  As described above, the thrust bearing 70 as a bearing is interposed between the shaft end surface of the stator 2 and the shaft end surface of the rotor 4, and the rotor 4 is restrained by the thrust bearing 70. For this reason, when the motor rotates, even if the magnetic attractive force and magnetic repulsive force generated between the stator 2 and the rotor 4 are large, the rotation caused by the magnetic attractive force and / or magnetic repulsive force. Shake of the shaft 40 is reduced, and consequently mechanical loss due to the shake of the rotating shaft 40 is reduced. Further, as shown in FIGS. 12 and 13, a pre-compression spring member 75 is interposed between the shaft end surface of the stator 2 and the shaft end surface of the rotor 4, and the backlash of the thrust bearing 70 is restricted. Therefore, the mechanical loss is further suppressed and the motor efficiency is improved. The spring member 75 is formed of a disc spring, but is not limited to this, and may be a leaf spring, a coil spring, or the like depending on circumstances.

  According to the third embodiment described above, the fixed iron core 20 of the stator 2 is set to have a circular cross section in the cross section along the direction perpendicular to the axis of the rotor 4, and therefore when the winding 26 is wound around the fixed iron core 20. In addition, contact between the winding 26 and the edge can be avoided, and the risk of damaging the winding 26 can be reduced. Further, since the stator 2 is fixed to the housing 1, the fixing property to the exciting coil layer 27 is improved, and the winding 26 constituting the exciting coil layer 27 is loosened even when an external force is applied to the housing 1. This can be prevented.

Embodiment 4

  FIG. 14 shows a fourth embodiment. The present embodiment has basically the same configuration as that of the first embodiment, and basically has the same functions and effects. Parts having common functions are denoted by the same reference numerals as much as possible. Hereinafter, a description will be given centering on portions different from the first embodiment. Between the shaft end surface of the stator 2 and the shaft end surface of the rotor 4, a sleeve bearing 77 (material: PEEK (polyether ether ketone)) is formed as a ring-shaped bearing formed of a material having a small friction coefficient. The sleeve bearing 77 can function as a regulating member having a function of maintaining a constant gap width of the gaps 15 and 16 between the shaft end surface of the stator 2 and the shaft end surface of the rotor 4. This can prevent fluctuations in the gap widths of the gaps 15 and 16 between the stator 2 and the rotor 4. Further, the magnetic attractive force generated between the stator 2 and the rotor 4 and / or The vibration of the rotating shaft 40 caused by the magnetic repulsive force can be reduced, and the mechanical loss due to the vibration of the rotating shaft 40 can be reduced, and the reliability of the motor can be increased.

  According to the above-described fourth embodiment, the fixed iron core 20 of the stator 2 is set to have a circular cross section in the cross section along the direction perpendicular to the axis of the rotor 4, and therefore when winding the winding 26 around the fixed iron core 20. In addition, the risk of damaging the winding 26 can be reduced. Further, since the stator 2 is fixed to the housing 1, the fixing property to the exciting coil layer 27 is improved, and the winding 26 constituting the exciting coil layer 27 is loosened even when an external force is applied to the housing 1. This can be prevented.

(Test Example 1)
Test Example 1 is based on the axial gap motor of the first embodiment. According to Test Example 1, the soft magnetic particles 5 forming the fixed iron core 20 and the yoke 41 described above have an average particle diameter of about 60 to 100 μm (80 μm), are water atomized powder particles, and are in a weight ratio. The iron purity is 99.95% or more. The insulating coating layer 50 is a film subjected to phosphorylation conversion treatment, and has a thickness of 100 to 300 nanometers. According to Test Example 1, loss such as eddy current loss can be reduced while increasing the magnetic permeability of the fixed iron core 20 and the yoke 41.

(Test Example 2)
Test example 2 is based on the axial gap motor of the first embodiment. According to Test Example 2, the soft magnetic particles 5 described above were obtained by coating an iron-based powder having an average particle diameter of 60 to 100 μm (80 μm) with Mn—Zn ferrite powder by mechanofusion. The thickness of the insulating coating layer 50 formed by mechanofusion of Mn—Zn ferrite powder is 1 to 3 micrometers. Then, the soft magnetic particles 5 having such an insulating coating layer 50 are loaded into a cavity of a molding die and warm compacted (150 ° C. in the atmosphere, molding pressure 9000 kgf / cm ² ≈882 MPa), thereby fixing the fixed iron core. 20, the yoke 41 is formed. According to Test Example 2, loss such as eddy current loss can be reduced while increasing the magnetic permeability of the fixed iron core 20 and the yoke 41.

(Test Example 3)
Test example 3 is based on the axial gap motor of the first embodiment. According to Test Example 3, the above-described soft magnetic particles 5 are obtained by adding Ni-Zn ferrite to an iron-based powder (gas atomized powder, iron purity is 99.95% or more by weight) having an average particle diameter of 60 to 100 μm (80 μm). Was coated by ferrite plating. The thickness of the Ni-Zn ferrite insulating coating layer 50 is 30 nanometers. Then, the soft magnetic particles 5 having such an insulating coating layer 50 are loaded into a cavity of a molding die and warm compacted (150 ° C. in the atmosphere, molding pressure 9000 kgf / cm ² ≈882 MPa), thereby fixing the fixed iron core. 20, the yoke 41 is formed. According to Test Example 3, losses such as eddy current loss can be reduced while increasing the magnetic permeability of the fixed core 20 and the yoke 41.

(Test Example 4)
Test Example 4 is based on the axial gap motor of the first embodiment. According to Test Example 4, for the soft magnetic particles 5B having the insulating coating layer 50 that forms the yoke 41, the thickness of the insulating coating layer 50 is larger than the soft magnetic particles 5A having the insulating coating layer 50 that forms the fixed iron core 20. Is set thick. In the soft magnetic particles 5A and 5B, the insulating coating layer 50 is made of the same material or a similar material. That the insulating coating layer 50 is made of the same material means that the main components constituting the insulating coating layer 50 are common.

  Since the fixed iron core 20 is fixed to the housing 1, no centrifugal force acts on the fixed iron core 20. On the other hand, since the rotor 4 rotates, a centrifugal force acts on the yoke 41 of the rotor 4. Further, when the motor is driven to rotate, the force in the directions of the arrows A1 and A2 acts on the yoke 41. For this reason, when the above-mentioned force is quite strong, it is preferable that the strength of the yoke 41 is high.

  Considering this point, the soft magnetic particles 5 having the insulating coating layer 50 forming the fixed iron core 20 and the soft magnetic particles 5 having the insulating coating layer 50 forming the yoke 41 are different. That is, when the thickness of the insulating coating layer 50 of the soft magnetic particles 5 forming the yoke 41 is t4 and the thickness of the insulating coating layer 50 of the soft magnetic particles 5 forming the fixed iron core 20 is t5, t4 <t5 is set. doing. This is advantageous in increasing the strength of the yoke 41 while increasing the specific resistance of the yoke 41 and reducing losses such as eddy current loss of the yoke.

(test)
Samples A to F were tested. Table 1 shows the basic conditions and test results tested for Samples A-F.

In sample A, the fixed iron core is formed of electromagnetic soft iron. In sample B, soft magnetic powder formed of iron powder on which no insulating coating layer was formed was used, and the aggregate of the soft magnetic powder was compression molded with a mold (temperature: room temperature, molding pressure: 5000 kgf / cm ² ≈ (4.9 × 10 ⁸ N / m), the fixed iron core is formed. In sample C, a soft magnetic powder in which an insulating coating layer (thickness: 30 to 50 nanometers) of a phosphoric acid film is coated on iron powder (average particle size: 80 to 100 micrometers) is used, and the phosphoric acid film is coated. The polyamide resin powder is mixed with 0.6% by weight of the externally applied polyamide resin powder to 100% by weight of the soft magnetic powder (polyamide resin powder + soft magnetic powder = 100.6% by weight). The assembly of the mixed powder with the powder is compression-molded with a mold (temperature: room temperature, molding pressure: 7000 kgf / cm ² ≈6.86 × 10 ⁸ N / m) and cured at 230 ° C. Is formed.

Sample D uses a soft magnetic powder in which an insulating coating layer (thickness: 30 to 50 nanometers) of a phosphoric acid film is coated with iron powder (average particle diameter: 80 to 100 micrometers). Is formed by compression molding (temperature: 150 ° C., molding pressure: 8000 kgf / cm ² ≈7.84 × 10 ⁸ N / m) with a mold. In sample E, soft magnetic powder obtained by coating an Mn-Zn ferrite insulating coating layer (thickness: 1 to 3 micrometers) on iron powder (average particle diameter: 80 to 100 micrometers) by mechanofusion treatment, The assembly of the soft magnetic powder is compression-molded with a molding die (temperature: 150 ° C., molding pressure: 9000 kgf / cm ² ≈8.82 × 10 ⁸ N / m), thereby forming a fixed iron core. .

Sample F uses a soft magnetic powder in which an Ni-Zn ferrite insulating coating layer (thickness: 40 to 100 nanometers) is coated with iron powder (average particle diameter: 80 to 100 micrometers) by ferrite plating. The assembly of the soft magnetic powder is compression-molded with a molding die (temperature: 150 ° C., molding pressure: 9000 kgf / cm ² ≈8.82 × 10 ⁸ N / m), thereby forming a fixed iron core. .

  The density, maximum magnetic permeability, specific resistance, and motor efficiency according to each of the samples A to F described above were tested. According to the test results, as shown in Table 1, according to Sample B in which the insulating coating layer was not formed, the specific resistance was considerably small and the motor efficiency was as low as 38%.

  On the other hand, according to Sample C in which the insulating coating layer is formed of a phosphoric acid film and polyamide, although the maximum magnetic permeability is low, the specific resistance is the highest, so the motor efficiency exceeds 50%, which is good Met.

According to the sample E on which the insulating coating layer of Mn—Zn ferrite was formed, the specific resistance could be increased while maintaining the maximum magnetic permeability satisfactorily, and the motor efficiency was also quite good. Further, according to the sample F on which the Ni-Zn ferrite insulating coating layer was formed, the specific resistance could be increased while maintaining the maximum magnetic permeability satisfactorily, and the motor efficiency was also quite good. Motor efficiency is defined as [(output (watt) / input (watt)) × 100%, input (watt) is voltage (volt) × current (ampere), output (watt) is 1.027 × 10 ⁻⁵ × N × T, where N is the number of revolutions (rpm) of the motor and T is the torque (gf · cm), or when the torque is T (N · m), the output ( Watt) is 10.065 × N × T.

(Other examples)
According to the first embodiment described above, the fixed iron core 20 and the yoke 41 are formed by loading the soft magnetic particles 5 having the insulating coating layer 50 into the cavity of the molding die and performing hot compacting. The conditions for warm compacting the fixed iron core 20 and the yoke 41 are not limited to the conditions described in the first embodiment. Furthermore, the fixed iron core 20 and the yoke 41 may be formed by loading the soft magnetic particles 5 into a cavity of a molding die and compacting at a normal temperature. In addition, the present invention is not limited to the embodiments described above and shown in the drawings, and can be implemented with appropriate modifications within a range not departing from the gist. The following technical idea can also be grasped from the above description.

[Additional Item 1] Housing;
A stator having a plurality of fixed iron cores fixed to the housing and arranged side by side in the rotation direction, and an exciting coil layer formed by winding a winding around each of the fixed iron cores;
Permanent magnets that are rotatably held in the housing so as to face the stator in the axial direction, and are arranged in parallel along the rotational direction so that the polarities of the magnetic poles alternate along the rotational direction. An axial gap motor that forms a gap between the shaft end surface of the stator and the shaft end surface of the rotor,
The side of the fixed iron core that faces the permanent magnet of the rotor has a protrusion that extends in the radially outward direction of the fixed iron core,
The axial gap motor according to claim 1, wherein the protrusion is a flange portion extending in a ring shape around the axis of the fixed iron core. Disengagement of the winding is prevented by the flange portion.

  [Additional Item 2] The axial gap motor according to Additional Item 1, wherein the flange portion has an inclined surface whose outer diameter decreases in a cross section along the axial center of the rotor toward the rotor. . In this case, since the flange portion of the fixed iron core has a high magnetic permeability, when power is supplied to the exciting coil layer to form a rotating magnetic field in the fixed iron core, the magnetic flux generated in the exciting coil layer is caused to flow along the inclined surface having a high magnetic permeability. This is advantageous for transmitting through the flange portion. Therefore, it is advantageous to direct the magnetic flux toward the center line (magnetic pole center) of the permanent magnet of the rotor. For this reason, the magnetic flux can be efficiently transmitted to the central region of the magnetic pole of the permanent magnet, which is advantageous in improving motor efficiency and suppressing coking torque, which is pulsating torque.

  The axial gap motor according to the present invention can be used as a brushless motor for vehicles such as automobiles, electrical equipment, electronic equipment, and the like.

It is sectional drawing (sectional drawing along the axial center of a rotor) of the axial gap motor which concerns on Embodiment 1. FIG. FIG. 3 is an end view of the stator according to the first embodiment. FIG. 3 is an end view of the rotor according to the first embodiment. It is a perspective view of the fixed iron core which is the main element which comprises a stator. It is sectional drawing (sectional drawing along the axis orthogonal direction of a rotor) of the stationary iron core which has arrange | positioned the exciting coil layer. It is a fragmentary sectional view (sectional view along the axis of a rotor) showing the neighborhood of the permanent magnet of a rotor, and the fixed iron core of a stator. It is a figure which shows typically the state which the permanent magnet of the rotor approached the fixed iron core of the stator. It is sectional drawing which shows a soft-magnetic particle typically. It is sectional drawing which shows typically the state which consolidated the aggregate | assembly of the soft-magnetic particle. It is sectional drawing (sectional drawing along the axial center of a rotor) of the stator which concerns on Embodiment 2. FIG. It is sectional drawing of the stator which concerns on Embodiment 2 along the XI-XI line of FIG. FIG. 10 is a cross-sectional view (a cross-sectional view along the axis of the rotor) of an axial gap motor according to the third embodiment, showing the upper half in cross-section. It is an expanded sectional view near a bearing. FIG. 10 is a cross-sectional view (a cross-sectional view taken along the axis of the rotor) of an axial gap motor according to the fourth embodiment, showing the upper half in cross-section. It is sectional drawing of the axial gap motor which concerns on a prior art example, and shows an upper half in cross section. It is a perspective view of a laminated body concerning a prior art example. It is sectional drawing of an axial gap motor concerning another prior art example. It is a perspective view of a stator according to another conventional example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 is a housing, 2 is a stator, 20 is a fixed iron core, 23 is a flange part, 24 is an inclined surface, 26 is winding, 27 is an exciting coil layer, 28 is a stator coating layer, 4 is a rotor, 40 is rotation A shaft, 41 is a yoke, 42 is a permanent magnet, 5 is a soft magnetic particle, 50 is an insulating coating layer, 51 is an iron-based powder particle, 70 is a thrust bearing (regulating member), and 77 is a sleeve bearing (regulating member).

Claims (7)

A housing;
A stator having a plurality of fixed iron cores fixed to the housing and arranged side by side in the rotation direction, and an exciting coil layer formed by winding a winding around each of the fixed iron cores;
Permanent magnets that are rotatably supported by the housing so as to face the stator in the axial direction, and are arranged in parallel along the rotational direction so that the polarities of the magnetic poles alternate along the rotational direction. And a rotor with
In the axial gap motor that forms a gap between the shaft end surface of the stator and the shaft end surface of the rotor,
The axial gap motor according to claim 1, wherein the fixed iron core of the stator is set to have a circular cross section in a cross section along a direction perpendicular to the axis of the rotor. In Claim 1, the side which faces the permanent magnet of the rotor among the fixed iron core has a projecting portion extending in the radially outward direction of the fixed iron core,
The axial gap motor according to claim 1, wherein the protrusion is a flange portion extending in a ring shape around the axis of the fixed iron core.   3. The axial gap motor according to claim 2, wherein the flange portion of the fixed iron core has an inclined surface whose outer diameter becomes smaller toward the rotor in a cross section along the axis of the rotor.   The fixed iron core according to any one of claims 1 to 3, wherein the fixed iron core is formed by consolidating an aggregate of soft magnetic particles having an insulating coating layer having high electrical insulation. Axial gap motor to be used. The rotor according to any one of claims 1 to 4, wherein the rotor includes a rotatable yoke and a permanent magnet held by the yoke.
The axial gap motor is characterized in that the yoke is formed by consolidating an aggregate of soft magnetic particles having an insulating coating layer having high electrical insulation.   In claim 5, when the thickness of the permanent magnet is t1, and the thickness of the yoke portion of the yoke that does not hold the permanent magnet is t2, t2 / t1 is set within the range of 1.5 to 4.0. An axial gap motor characterized by   7. The insulating coating layer of the soft magnetic particles forming the yoke is set to be thinner than the insulating coating layer of the soft magnetic particles forming the fixed iron core according to claim 5. Axial gap motor characterized by that.

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