JP2009201215A - Rotating electrical machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotating electrical machine which holds a permanent magnet with a yoke part, eliminates increase in rocking of a claw-like magnetic pole part at high-speed rotation due to the arrangement of the permanent magnet, suppresses drop in the output due to the increase of an air gap, and stably holds the permanent magnet using a simple holding structure. <P>SOLUTION: A first engagement groove 31 opens outward in a radial direction and to a field coil-side in an axial direction and is dented in a wedge-shaped groove shape, in a part confronted with a tip-side inner peripheral face of a second claw-like magnetic pole part 24 of a first yoke part 19; a lower end part-side of a first permanent magnet 30 is engaged with the first engagement groove 31 and is held by the first yoke part 19; an upper face is arranged to confront with the tip-side inner peripheral face of the second claw-like magnetic pole part 24; a first magnet holder 32 is fixed to the first yoke part 19 to block a field coil-side opening in the axial direction of the first engagement groove 31, and regulates movement in the axial direction of the first permanent magnet 30; and the first permanent magnet 30 is magnetized and oriented, in a direction which is reverse to that to that of the magnetic field which the field coil generates. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rotating electrical machine such as a vehicular AC generator, and more particularly to a permanent magnet holding structure in a Landel rotor.

  Vehicle alternators using Landel rotors have been used in automobiles for decades. Due to environmental problems in recent years, the load of electrical components mounted on the vehicle has increased rapidly, and it is required to further increase the power generation amount of the Landel rotor.

  In view of such a situation, a Landell-type rotor has been proposed in which permanent magnets are disposed between the claw-shaped magnetic pole portions to reduce the leakage magnetic flux between the claw-shaped magnetic pole portions and improve the output ( For example, see Patent Document 1).

Japanese Patent Laid-Open No. 05-207716

  In the conventional Landell type rotor, the non-magnetic member is used to hold the permanent magnet between the claw-shaped magnetic pole portions. Therefore, the mass of the permanent magnet and the non-magnetic member is added to the claw-shaped magnetic pole portion, and at high speed rotation. An excessive centrifugal force acts on the claw-shaped magnetic pole portion, and the claw-shaped magnetic pole portion swings greatly. As a result, in order to avoid interference between the claw-shaped magnetic pole part and the stator core, it is necessary to increase the air gap between the rotor core and the stator core. There was a problem that it could not be used and the output was reduced. Further, there has been a problem that the swinging of the claw-shaped magnetic pole part during high-speed rotation affects the holding structure of the permanent magnet, making it impossible to hold the permanent magnet stably.

  The present invention has been made to solve the above-described problems. The permanent magnet is held by the yoke portion, and the claw-shaped magnetic pole portion is swung during high-speed rotation due to the arrangement of the permanent magnet. To obtain a rotating electrical machine that eliminates an increase in movement and can suppress a decrease in output due to an increase in an air gap between the rotor core and the stator core, and can stably hold a permanent magnet with a simple holding structure. With the goal.

  The rotating electrical machine according to the present invention includes a boss portion, a pair of yoke portions extending radially outward from both axial end edges of the boss portion, and an axial direction alternately from each of the pair of yoke portions. A pole core that has a plurality of claw-shaped magnetic pole portions that are extended and meshed with each other and arranged in the circumferential direction, fixed to a shaft that is inserted through the axial center of the boss portion, the boss portion, and the pair of yokes And a field coil housed in a space surrounded by the plurality of claw-shaped magnetic pole portions, and an outer periphery of the rotor is disposed so as to surround a predetermined air gap. And a stator. The rotating electrical machine opens in the radially outward direction and the axial field coil side in a portion of the yoke portion facing the tip-side inner peripheral surface of the claw-shaped magnetic pole portion, and is recessed in a wedge-shaped groove shape. The fitting groove and the lower end side are fitted into the fitting groove and held by the yoke part, and the upper surface is arranged to face the inner peripheral surface of the tip side of the claw-shaped magnetic pole part. The permanent magnet is fixed to the yoke portion, closes the axial field coil side opening of the fitting groove, and restricts the axial movement of the permanent magnet fitted in the fitting groove. A magnet holder, and the permanent magnet is magnetized and oriented in the direction opposite to the magnetic field produced by the field coil.

According to the present invention, since the permanent magnet is fitted in the fitting groove and held in the yoke portion, the mass of the permanent magnet is not added to the claw-shaped magnetic pole portion and acts on the claw-shaped magnetic pole portion during high-speed rotation. There is no increase in centrifugal force. Therefore, since the increase in the swing of the claw-shaped magnetic pole part due to the arrangement of the permanent magnet is suppressed, it is not necessary to increase the air gap between the stator and the rotor, and the magnetic flux generated by the field coil can be efficiently generated. The output can be improved. Further, the swinging of the permanent magnet during high-speed rotation does not affect the permanent magnet holding structure, and the permanent magnet holding structure can be realized with a simple structure.
Further, since the permanent magnet is magnetized and oriented in the direction opposite to the magnetic field generated by the field coil, the magnetic flux density of the magnetic material constituting the pole core can be greatly reduced, and magnetic saturation is eliminated. Thereby, the magnetic flux linked to the stator increases, and the power generation amount can be increased.

Embodiment 1 FIG.
1 is a cross-sectional view schematically showing an automotive alternator according to Embodiment 1 of the present invention, and FIG. 2 is a schematic diagram of a permanent magnet holding structure in the automotive alternator according to Embodiment 1 of the present invention. It is a fractured perspective view which shows a part.

  1 and 2, an automotive alternator 1 is supported by a case 4 comprising a substantially bowl-shaped aluminum front bracket 2 and a rear bracket 3 and a shaft 16 on the case 4 via a bearing 5. The rotor 13 rotatably disposed in the case 4, the pulley 6 fixed to the end of the shaft 16 extending to the front side of the case 4, and the axial direction of the rotor 13 (hereinafter referred to as shaft) A fan 7 fixed to both end faces of the direction), a stator 10 having a constant air gap 29 with respect to the rotor 13 and surrounding the outer periphery of the rotor 13 and fixed to the case 4; A pair of slip rings 8 fixed to the rear side of the shaft 16 and supplying current to the rotor 13, and a pair of brushes 9 disposed in the case 4 so as to slide on the slip rings 8 are provided. ing. Although not shown, a rectifier that rectifies alternating current generated in the stator 10 into direct current, a voltage regulator that adjusts the magnitude of the alternating voltage generated in the stator 10, and the like are disposed in the case 4. .

  The stator 10 is wound around a cylindrical stator core 11 and the stator core 11, and an alternating current is generated by a change in magnetic flux from a field coil 14 (to be described later) as the rotor 13 rotates. And.

The rotor 13 includes a field coil 14 that generates a magnetic flux when an excitation current is passed, a pole core 15 that is provided so as to cover the field coil 14, and a magnetic pole is formed by the magnetic flux, and an axial center position of the pole core 15. And a shaft 16 penetrating into the shaft.
The pole core 15 is divided into first and second pole core bodies 17 and 21 made of a low carbon steel such as S10C by a cold forging method.

  The first pole core body 17 has a cylindrical outer peripheral surface, a first boss portion 18 formed with a shaft insertion hole 18a penetrating the axial center position, and radially outward from one end edge of the first boss portion 18. A thick ring-shaped first yoke portion 19 that is extended, and a first claw-shaped magnetic pole portion 20 that extends from the outer peripheral portion of the first yoke portion 19 to the other end side in the axial direction are provided. . The first claw-shaped magnetic pole portion 20 has a substantially trapezoidal outermost surface shape, the circumferential width gradually decreases toward the distal end side, and the radial thickness gradually decreases toward the distal end side. It is formed in a tapered shape, and eight, for example, are arranged on the outer peripheral portion of the first yoke portion 19 at an equiangular pitch in the circumferential direction.

  The second pole core body 21 has a cylindrical outer peripheral surface, a second boss portion 22 formed with a shaft insertion hole 22a passing through the axial center position, and a radially outer side from the other end edge of the second boss portion 22. A thick ring-shaped second yoke portion 23 extending from the outer periphery of the second yoke portion 23 and a second claw-shaped magnetic pole portion 24 extending to one end in the axial direction. . The second claw-shaped magnetic pole portion 24 has a substantially trapezoidal outermost surface shape, its circumferential width gradually decreases toward the distal end side, and its radial thickness gradually decreases toward the distal end side. For example, eight taper shapes are arranged on the outer peripheral portion of the second yoke portion 23 at an equiangular pitch in the circumferential direction.

  The first and second pole core bodies 17 and 21 configured as described above mesh with the first and second claw-shaped magnetic pole portions 20 and 24 alternately, and the other end surface of the first boss portion 18 is connected to the second boss. It abuts on one end surface of the portion 22 and is fixed to the shaft 16 penetrating the shaft insertion holes 18a, 22a. A field coil 14 wound around a bobbin (not shown) includes first and second boss portions 18 and 22, first and second yoke portions 19 and 23, and first and second claw-shaped magnetic poles. It is mounted in a space surrounded by the parts 20 and 24. Here, the first and second boss portions 18 and 22 and the first and second yoke portions 19 and 23 correspond to the boss portion of the pole core 15 and the pair of yoke portions, respectively. Further, in the axial direction, the tip portions of the first and second claw-shaped magnetic pole portions 20 and 24 overlap the second and first yoke portions 23 and 19, respectively.

  The first permanent magnet 30 has a rectangular lower surface, a lower surface perpendicular to the lower surface, both side surfaces in the width direction consisting of parallel flat surfaces, an acute angle with the lower surface, and perpendicular to both side surfaces. An end face on one side of the thickness direction consisting of a flat surface, an end face on the other side of the thickness direction consisting of a flat surface orthogonal to the lower surface and both side faces, an orthogonal angle to the end face on one side of the thickness direction, perpendicular to both side faces It is manufactured in a columnar body that includes an upper surface that intersects the other end surface in the thickness direction and a flat surface that intersects an obtuse angle.

  The first fitting groove 31 opens to the outer side in the radial direction and the other end side in the axial direction at the portion of the first yoke portion 19 facing the inner peripheral surface on the front end side of the second claw-shaped magnetic pole portion 24. The permanent magnet 30 is recessed in a groove shape for fitting the lower end side. In other words, the first fitting groove 31 has a rectangular cross-sectional shape orthogonal to the radial direction, and the axial length of the cross-sectional rectangle whose inner wall surface on one end side in the axial direction is orthogonal to the radial direction is directed outward in the radial direction. It is formed in the shape of a wedge-shaped groove formed on an inclined surface that is gradually shortened. The 1st magnet holder 32 is produced in the rectangular flat plate shape which has predetermined thickness using steel materials, such as SS material and SUS material, for example.

  The first permanent magnet 30 is inserted into the first fitting groove 31 from the other end side in the axial direction with its lower end side aligned with the axial direction in the thickness direction. Further, the first magnet holder 32 is fixed to the other end surface in the axial direction of the first yoke portion 19 by welding, adhesion or the like, and closes the opening on the other end side in the axial direction of the first fitting groove 31. Accordingly, the first permanent magnet 30 has a lower surface on the bottom surface of the first fitting groove 31, both side surfaces on the inner wall surfaces in the circumferential direction of the first fitting groove 31, and an end surface on one side in the thickness direction being the first. The fitting groove 31 is fitted and held in the first fitting groove 31 in close contact with the inner wall surface at one end in the axial direction and the end face on the other side in the thickness direction on the surface of the first magnet holder 32. . Therefore, the movement of the first permanent magnet 30 in the circumferential direction is regulated by both inner wall surfaces in the circumferential direction of the first fitting groove 31, and the inner wall surface on the one end side in the axial direction of the first fitting groove 31 and the first magnet. Movement in the axial direction and the radial direction is restricted by the holder 32. The upper surface of the first permanent magnet 30 is opposed to the tip end side inner peripheral surface of the second claw-shaped magnetic pole portion 24 in a substantially parallel manner with a predetermined gap.

  The second permanent magnet 35 has a rectangular lower surface, a lower surface perpendicular to the lower surface, and both widthwise side surfaces that are parallel to each other, an acute angle with the lower surface, and perpendicular to the both surfaces. An end face on the other side of the thickness direction consisting of a flat surface, an end face on one side of the thickness direction consisting of a flat face perpendicular to the lower surface and both side faces, and an acute angle with the end face on the other side of the thickness direction perpendicular to both side faces. It is manufactured in a columnar body that includes an upper surface that intersects an end surface on one side in the thickness direction and a flat surface that intersects an obtuse angle.

  The second fitting groove 36 opens to the outer side in the radial direction and one end in the axial direction at a portion of the second yoke portion 23 that faces the inner peripheral surface of the tip end side of the first claw-shaped magnetic pole portion 20, and is second permanent. The magnet 35 is recessed in a groove shape for fitting the lower end portion side thereof. That is, the second fitting groove 36 has a rectangular cross-sectional shape orthogonal to the radial direction, and the inner wall surface at the other end in the axial direction faces the axial length of the cross-sectional rectangle orthogonal to the radial direction outward in the radial direction. Thus, it is formed into a wedge-shaped groove formed on an inclined surface that is gradually shortened. The 2nd magnet holder 37 is produced in the rectangular flat plate shape which has predetermined thickness, using steel materials, such as SS material and SUS material, for example.

  Then, the second permanent magnet 35 is inserted into the second fitting groove 36 from the one end side in the axial direction with the lower end side thereof being matched with the axial direction in the thickness direction. Furthermore, the second magnet holder 37 is fixed to one end surface in the axial direction of the second yoke portion 23 by welding, adhesion, or the like, and closes the opening on the one end side in the axial direction of the second fitting groove 36. Thus, the second permanent magnet 35 has a lower surface on the bottom surface of the second fitting groove 36, both side surfaces on the inner wall surfaces in the circumferential direction of the second fitting groove 36, and the other end surface in the thickness direction on the second side. The fitting groove 36 is fitted and held in the second fitting groove 36 with the inner wall surface on the other axial end side in close contact with the end surface on the one side in the thickness direction on the surface of the second magnet holder 37. Yes. Accordingly, the movement of the second permanent magnet 35 in the circumferential direction is restricted by both inner wall surfaces in the circumferential direction of the second fitting groove 36, and the second inner surface of the second fitting magnet 36 on the other end side in the axial direction of the second fitting groove 36. Movement in the axial direction and the radial direction is restricted by the magnet holder 37. The upper surface of the second permanent magnet 35 is substantially parallel to the distal end side inner peripheral surface of the first claw-shaped magnetic pole part 20 with a predetermined gap.

  Thus, the 1st and 2nd permanent magnets 30 and 35 hold | maintained at the 1st and 2nd yoke parts 19 and 23 are the 1st and 2nd nail | claw-shaped magnetic pole parts 24 and 20 1st from the radial direction outer side. And it is located in the projection area | region obtained by projecting on the 2nd yoke part 19,23. Further, as shown in FIG. 1, the first and second permanent magnets 30 and 35 are magnetized and oriented in a direction opposite to the direction of the magnetic field 40 generated when the field coil 14 is energized. That is, the first permanent magnet 30 is magnetized and oriented so that the magnetizing direction 41 faces radially outward, and the second permanent magnet 35 is magnetized and oriented so that the magnetizing direction 41 faces radially inward. Has been. In the case of a design in which the direction of the magnetic field 40 generated by the field current flowing through the field coil 14 is reversed, the first and second permanent magnets 30 and 35 are also magnetized and oriented in opposite directions.

Next, the operation of the vehicular AC generator 1 configured as described above will be described.
First, a current is supplied from a battery (not shown) to the field coil 14 of the rotor 13 via the brush 9 and the slip ring 8, and a magnetic flux is generated. By this magnetic flux, the first claw-shaped magnetic pole part 20 of the first pole core body 17 is magnetized to the N pole, and the second claw-shaped magnetic pole part 24 of the second pole core body 21 is magnetized to the S pole.
On the other hand, the rotational torque of the engine is transmitted to the shaft 16 via a belt (not shown) and the pulley 6, and the rotor 13 is rotated. Therefore, a rotating magnetic field is applied to the stator coil 12 of the stator 10, and an electromotive force is generated in the stator coil 12. This AC electromotive force is rectified into a DC current by a rectifier, and the battery is charged or supplied to an electric load.

  Magnetic flux generated by energizing the field coil 14 enters the teeth portion of the stator core 11 from the first claw-shaped magnetic pole portion 20 through the air gap 29. The magnetic flux that has entered the stator core 11 moves in the circumferential direction from the tooth portion of the stator core 11 through the core back portion, and passes through the air gap 29 from the tooth portion facing the adjacent second claw-shaped magnetic pole portion 24. The second claw-shaped magnetic pole portion 24 enters. Next, the magnetic flux that has entered the second claw-shaped magnetic pole portion 24 passes through the second yoke portion 23, the second boss portion 22, the first boss portion 18, and the first yoke portion 19, and the first claw-shaped magnetic pole portion 20. To. Here, in the conventional Landell type rotor, the first and second pole core bodies are designed to be limited, so that magnetic saturation occurs due to the magnetic field generated by the field coil, and the magnetic flux generated in the rotor decreases.

  In the rotor 13, the first and second permanent magnets 30 and 35 are magnetized and oriented so as to be opposite to the direction of the magnetic field 40 generated by the field coil 14. Therefore, the magnetic flux generated from the first permanent magnet 30 enters the first yoke portion 19 and passes through the first boss portion 18, the second boss portion 22, the second yoke portion 23, and the second claw-shaped magnetic pole portion 24. Return to the first permanent magnet 30 through the gap. Further, the magnetic flux generated from the second permanent magnet 35 enters the first claw-shaped magnetic pole part 20 through the air gap, and the first yoke part 19, the first boss part 18, the second boss part 22, and the second yoke. Return to the second permanent magnet 35 through the section 23. The magnetic flux generated by the first and second permanent magnets 30 and 35 is opposite to the magnetic flux generated by the field coil 14, greatly increasing the magnetic flux density of the magnetic bodies constituting the first and second pole core bodies 17 and 21. Can be reduced, and magnetic saturation can be eliminated.

  Thus, according to this Embodiment 1, in this rotor 13, the magnetic field which the field coil 14 generate | occur | produces by devising arrangement | positioning and the magnetization direction 41 of the 1st and 2nd permanent magnets 30 and 35. The magnetic saturation of the first and second pole core bodies 17 and 21 due to is relaxed. Thereby, the magnetic flux linked to the stator 10 increases, and the amount of power generation can be increased.

  The first permanent magnets 30 having the magnetizing direction 41 radially inward are arranged side by side in the circumferential direction on one axial end side of the rotor 13 and the second permanent having the magnetizing direction 41 radially outward. Magnets 35 are arranged side by side in the circumferential direction on the other axial end side of the rotor 13. Therefore, the group of the first permanent magnets 30 and the group of the second permanent magnets 35 are arranged apart from each other in the axial direction of the rotor 13, and are therefore arranged in the circumferential direction on each end side in the axial direction. The magnetization orientation directions of all the permanent magnets are uniformed radially inward or radially outward.

In addition, since the first and second permanent magnets 30 and 35 are disposed so as to face the inner peripheral surfaces of the distal ends of the second and first claw-shaped magnetic pole portions 24 and 20, the first and second permanent magnets The magnetic circuits 30 and 35 are closed inside the rotor 13. Therefore, the magnetic flux component (leakage magnetic flux) linked to the stator core 11 in the magnetic flux generated by the first and second permanent magnets 30 and 35 is eliminated. As a result, the generation of induced voltages of the first and second permanent magnets 30 and 35 during no-load no-excitation is suppressed.
The first and second permanent magnets 30 and 35 project the tip portions of the second and first claw-shaped magnetic pole portions 24 and 20 onto the first and second yoke portions 19 and 23 from the radially outer side. Therefore, the first and second permanent magnets 30 and 35 are not exposed to the stator 10 side, and induction heating due to the stator slot harmonics is reliably prevented, and thermal demagnetization is performed. Can be prevented.

  In addition, since the first and second permanent magnets 30 and 35 are directly held by the first and second yoke portions 19 and 23, the centrifugal force acting on the first and second permanent magnets 30 and 35 is the first. Further, it is not added to the second claw-shaped magnetic pole portions 30 and 35, and an increase in the swing of the first and second claw-shaped magnetic pole portions 20 and 24 during high-speed rotation is suppressed. Therefore, there is no increase in the air gap 29 between the stator 10 and the rotor 13 due to the arrangement of the first and second permanent magnets 30 and 35, and the magnetic flux generated by the field coil 14 can be efficiently used. The output is improved. Further, since the swing of the first and second claw-shaped magnetic pole portions 20 and 24 during high-speed rotation does not affect the holding structure of the first and second permanent magnets 30 and 35, the first and second permanent magnets 30 and 35 The holding structure can be realized with a simple structure.

  The first fitting groove 31 has a wedge-shaped groove shape with the inner wall surface on one end side in the axial direction as an inclined surface, and the first magnet holder 32 is fixed to the other end surface in the axial direction of the first yoke portion 19. The opening on the other end side in the axial direction of the one fitting groove 31 is closed. Therefore, when the centrifugal force acts on the first permanent magnet 30, the first permanent magnet 30 slides on the inner wall surface on the one end side in the axial direction of the first fitting groove 31 and moves radially outward. Try to move to the other axial end. At this time, since the first magnet holder 32 restricts the movement of the first permanent magnet 30 toward the other end in the axial direction, the first permanent magnet 30 is prevented from jumping out. Thus, the first permanent magnet 30 is fitted into the wedge-shaped groove-shaped first fitting groove 31 formed in the first yoke portion 19 so as to open to the radially outer side and the other axial end side, The first magnet holder 32 is fixed to the other end surface in the axial direction of the first yoke portion 19 and the opening on the other end side in the axial direction of the first fitting groove 31 is closed. The permanent magnet 30 can be stably held.

  The second fitting groove 36 has a wedge-shaped groove shape with the inner wall surface on the other end side in the axial direction as an inclined surface, and the second magnet holder 37 is fixed to one end surface in the axial direction of the second yoke portion 23. An opening on one end side in the axial direction of the second fitting groove 36 is closed. Therefore, when the centrifugal force acts on the second permanent magnet 35, the second permanent magnet 35 slides on the inner wall surface on the other end side in the axial direction of the second fitting groove 36 and moves radially outward. While trying to move to one end side in the axial direction. At this time, since the second magnet holder 37 restricts the movement of the second permanent magnet 35 toward the one end side in the axial direction, the second permanent magnet 35 is prevented from popping out. In this manner, the second permanent magnet 35 is fitted into the wedge-shaped groove-shaped second fitting groove 36 formed in the second yoke portion 23 so as to open to the radially outer side and the one axial end side. The second permanent magnet has a simple holding structure in which the two magnet holder 37 is fixed to one end surface in the axial direction of the second yoke portion 23 and the opening on the one end side in the axial direction of the second fitting groove 36 is closed. 35 can be stably held.

The first and second permanent magnets 30 and 35 are preferably sintered rare earth magnets such as neodymium / iron / boron magnets or samarium cobalt magnets having a high magnetic flux density.
The first and second permanent magnets 30 and 35 are wedge-shaped grooves whose lower ends are defined by the first and second fitting grooves 31 and 36 and the first and second magnet holders 32 and 37. The shape of the extension from the wedge-shaped groove is not particularly limited as long as it has a shape to be fitted and held.
In addition, the first and second fitting grooves 31 and 36 are formed in a wedge-like groove shape having one inner wall surface in the axial direction as an inclined surface. The grooves of the first and second fitting grooves The shape is not limited to this, and for example, the first and second fitting grooves have both the inner wall surfaces in the circumferential direction as inclined surfaces, or one inner wall surface in the circumferential direction as an inclined surface, It is good also as a wedge-shaped groove shape which the circumferential direction width | variety of an orthogonal cross section reduces gradually toward radial direction outward.

Embodiment 2. FIG.
3 is a cutaway perspective view showing a main part of a permanent magnet holding structure in an automotive alternator according to Embodiment 2 of the present invention, and FIG. 4 shows an automotive alternator according to Embodiment 2 of the present invention. It is a perspective view which shows the magnet protective cover applied. Although the second magnet protective cover is not shown, it is configured in the same manner as the first magnet protective cover, so only the first permanent magnet fixing structure will be described here.

3 and 4, the first magnet protection cover 33 is formed in a frame shape that covers the upper and lower surfaces of the first permanent magnet 30 and both end surfaces in the thickness direction by bending a thin plate of SUS material. And the 1st permanent magnet 30 makes the thickness direction correspond to an axial direction in the state in which the 1st magnet protective cover 33 was mounted | worn, and the lower end part side is the inside of the 1st fitting groove | channel 31 from an axial direction other end side. Has been inserted. Further, the first magnet holder 32 is fixed to the other end surface in the axial direction of the first yoke portion 19 by welding, adhesion or the like, and closes the opening on the other end side in the axial direction of the first fitting groove 31. Accordingly, the first permanent magnet 30 has a lower surface on the bottom surface of the first fitting groove 31 via the first magnet protective cover 33, and both side surfaces on the inner wall surfaces in the circumferential direction of the first fitting groove 31. End surfaces on both sides in the direction are in close contact with the inner wall surface on one axial end side of the first fitting groove 31 and the surface of the first magnet holder 32 via the first magnet protective cover 33, respectively. 31 is fitted and held.
Other configurations are the same as those in the first embodiment.

In the second embodiment, the first magnet protection cover 33 is attached so as to cover the upper and lower surfaces of the first permanent magnet 30 and both end surfaces in the axial direction. Therefore, when the second claw-shaped magnetic pole portion 24 is swung by a centrifugal force or a foreign object comes and collides with the first permanent magnet 30, the first magnet protective cover 33 functions as a buffer material, and the first Generation | occurrence | production of the crack of a permanent magnet 30 and a chip | tip can be suppressed. Even if the first permanent magnet 30 is cracked or chipped, the first magnet protective cover 33 prevents the broken or chipped magnet pieces from being scattered from the first permanent magnet 30.
Further, since the first magnet protective cover 33 is interposed between the axial end surfaces of the first permanent magnet 30 and the first yoke portion 19 and the first magnet holder 32, the first permanent magnet 30. Generation | occurrence | production of the abrasion resulting from a displacement with respect to the 1st yoke part 19 and the 1st magnet holder 32 is suppressed.

In the second embodiment, the first magnet protective cover 33 is formed so as to cover the upper and lower surfaces of the first permanent magnet 30 and both end surfaces in the axial direction. In addition to the upper and lower surfaces of the first permanent magnet and both end surfaces in the axial direction, the first permanent magnet may be manufactured so as to cover both side surfaces in the circumferential direction.
When the magnet protective cover is made of a magnetic material, a magnetic path is formed in which the magnetic flux generated by the permanent magnet returns to the permanent magnet through the magnet protective cover. As a result, since the amount of magnetic flux entering the opposing claw-shaped magnetic pole portions is reduced, it is necessary to increase the magnet amount of the permanent magnet. For this reason, it is desirable that the magnet protective cover be made of a nonmagnetic material such as SUS material or synthetic resin.

Embodiment 3 FIG.
5 is a cutaway perspective view showing a main part of a permanent magnet holding structure in an automotive alternator according to Embodiment 3 of the present invention, and FIG. 6 shows an automotive alternator according to Embodiment 3 of the present invention. It is a perspective view which shows the magnet protective cover applied. In addition, although the 2nd magnet holder is not shown in figure, since it is comprised similarly to a 1st magnet holder, only the fixing structure of a 1st permanent magnet is demonstrated here.

5 and 6, the first magnet holder 34 is a first yoke located between the first claw-shaped magnetic pole portions 20 adjacent to each other in the circumferential direction by bending a steel material such as an SS material or an SUS material. The portion 19 is formed in a U-shaped cross section covering both axial end faces and a radially outer peripheral face. Further, a through hole 34 d through which the first permanent magnet 30 is inserted is formed in the bottom 34 a of the first magnet holder 34. The first permanent magnet 30 is inserted into the first fitting groove 31 from the other end side in the axial direction with its lower end side aligned with the axial direction in the thickness direction. Further, the first magnet holder 34 is mounted so that the bottom 34 a is in contact with the outer circumferential surface of the first yoke portion 19 while the first permanent magnet 30 is inserted into the through hole 34 d from above in the radial direction. The first magnet holder 34 is fixed by welding, bonding or the like with both side sides 34b and 34c being in close contact with both axial end surfaces of the first yoke portion 19, and the first fitting groove 31 in the axial direction. The opening on the other end side is closed.
Other configurations are the same as those in the first embodiment.

  In the third embodiment, the first magnet holder 34 is fixed to the first yoke portion 19 in close contact with the radially outer circumferential surface and both axial end surfaces of the first yoke portion 19, and the first permanent magnet 30 is The through hole formed in the bottom 34 a of the first magnet holder 34 is inserted. Therefore, the rigidity of the first magnet holder 34 against the centrifugal force acting on the first permanent magnet 30 is increased, and the radial movement of the first permanent magnet 30 can be reliably restricted. Thereby, the displacement to the radial direction outward of the 1st permanent magnet 30 is suppressed, and the clearance gap between the upper surface of the 1st permanent magnet 30 and the front end side inner peripheral surface of the 2nd nail | claw-shaped magnetic pole part 24 is highly accurate. Can be managed.

  In each of the above embodiments, the vehicle alternator has been described. However, the present invention is not limited to the vehicle alternator, and is applied to rotating electric machines such as a vehicle motor and a vehicle generator motor. Produces the same effect.

  In each of the above embodiments, the permanent magnet is held by the yoke portion so as to face the tip side of all the claw-shaped magnetic pole portions, but the permanent magnet is placed on the tip side of any claw-shaped magnetic pole portion. You may make it select and hold | maintain in a yoke part so that it may oppose. In this case, it is desirable to arrange the permanent magnets in a balanced manner in the circumferential direction. For example, a permanent magnet is disposed only on one of the first and second pole core bodies, or the pole core bodies of the first and second pole core bodies are permanent so as to face every other claw-shaped magnetic pole portion in the circumferential direction. A magnet may be provided. Taking such a configuration can reduce the number of parts and output with an inexpensive configuration, although the output is slightly lower than when permanent magnets are arranged so as to face all the claw-shaped magnetic poles. I can give you.

1 is a cross-sectional view schematically showing an automotive alternator according to Embodiment 1 of the present invention. It is a fractured perspective view showing the principal part of the permanent magnet holding structure in the automotive alternator according to Embodiment 1 of the present invention. It is a fracture | rupture perspective view which shows the principal part of the holding structure of the permanent magnet in the alternating current generator for vehicles concerning Embodiment 2 of this invention. It is a perspective view which shows the magnet protection cover applied to the vehicle alternator which concerns on Embodiment 2 of this invention. It is a fracture | rupture perspective view which shows the principal part of the holding structure of the permanent magnet in the alternating current generator for vehicles concerning Embodiment 3 of this invention. It is a perspective view which shows the magnet protection cover applied to the alternating current generator for vehicles concerning Embodiment 3 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Stator, 13 Rotor, 14 Field coil, 15 Pole core, 16 Shaft, 17 1st pole core body, 18 1st boss | hub part, 19 1st yoke part, 20 1st claw-shaped magnetic pole part, 21 2nd pole core Body, 22 second boss part, 23 second yoke part, 24 second claw-shaped magnetic pole part, 29 air gap, 30 first permanent magnet, 31 first fitting groove, 32, 34 first magnet holder, 33 1st magnet protective cover, 35 2nd permanent magnet, 36 2nd fitting groove, 37 2nd magnet holder, 40 magnetic field, 41 magnetization direction.

Claims (4)

A boss portion, a pair of yoke portions extending radially outward from both end edges in the axial direction of the boss portion, and a pair of yoke portions alternately extending in the axial direction from each of the yoke portions, meshing with each other. A pole core fixed to a shaft having a plurality of claw-shaped magnetic pole portions arranged in a direction and inserted through an axial center position of the boss portion; the boss portion; the pair of yoke portions; and the plurality of claws A rotor having a field coil housed in a space surrounded by a magnetic pole portion,
In a rotating electrical machine comprising: a stator disposed so as to surround an outer periphery of the rotor via a predetermined air gap;
A fitting that opens to the radially outer side and the axial field coil side and is recessed in the shape of a wedge-shaped groove at a portion of the yoke portion that faces the inner peripheral surface of the claw-shaped magnetic pole portion. Groove,
A permanent magnet that is fitted in the fitting groove on the lower end side and held in the yoke portion, and has an upper surface disposed so as to face the inner peripheral surface on the tip side of the claw-shaped magnetic pole portion;
A magnet holder fixed to the yoke portion, closing the axial field coil side opening of the fitting groove, and restricting axial movement of the permanent magnet fitted in the fitting groove; Have
A rotating electrical machine, wherein the permanent magnet is magnetized and oriented in a direction opposite to a magnetic field produced by the field coil.   The rotating electrical machine according to claim 1, wherein a magnet protective cover is attached to the permanent magnet so as to cover the permanent magnet.   The magnet holder is mounted so as to cover a radial outer peripheral surface and both axial end surfaces of the yoke portion, and is fixed to both axial end surfaces of the yoke portion. The rotating electrical machine according to claim 1 or 2.   The said permanent magnet is arrange | positioned so that it may be located in the projection area | region obtained by projecting the front-end | tip part of the said nail | claw-shaped magnetic pole part on the said yoke part from radial direction outward. The rotating electrical machine according to any one of claims 1 to 3.

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