JP4430691B2 - Rotating electric machine - Google Patents

Description

  The present invention relates to a rotating electrical machine such as a vehicular AC generator, and more particularly to a Landell type rotor structure equipped with a permanent magnet.

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 a further increase in the power generation amount of the Landel rotor has been demanded.
If it is going to respond to this request in the conventional design range, a generator will be enlarged. Increasing the size of the generator is not preferable because it increases the weight and space of the generator. In addition, it is known that an increase in the size of the generator causes an increase in the rotor inertia, which causes a new problem that the fluctuation of the engine speed and the inertia torque of the generator interact to cause vibration and slippage of the belt. Yes.
Therefore, it is required to increase the generator capacity while maintaining the current size of the generator body.

Conventionally, in order to solve such a problem, a means for arranging a permanent magnet between claw-shaped magnetic poles facing the circumferential direction of a Landel-type rotor has been taken (for example, see Patent Documents 1 and 2). .
Furthermore, as a method for mounting the magnet, a U-shaped magnet is fitted into the claw tip of the claw-shaped magnetic pole and held on the claw-shaped magnetic pole (see, for example, Patent Document 3) or wound around the boss portion of the rotor core. There is a method in which a ring-shaped magnet is disposed on the outer periphery of a cylindrical field coil and the magnet is held by a claw-shaped magnetic pole (see, for example, Patent Document 4).

As described above, various conventional methods for holding a permanent magnet have been proposed for an AC generator for a vehicle. In order to put these permanent magnet holding methods into practical use, (1) reliability of holding a permanent magnet. It is necessary to improve the performance, (2) to suppress the induced voltage of no-load non-excitation, and (3) to avoid thermal demagnetization of the magnet due to the high-frequency magnetic field induced by the stator slot.
Hereinafter, each factor will be described.

(1) About the retention strength of a permanent magnet The vehicular AC generator driven by the rotational force of the engine transmitted through the belt and pulley rotates at a maximum speed of about 18,000 to 20,000 rpm. Therefore, even if a small magnet of about several grams per pole is disposed, an extremely large centrifugal force exceeding several tens Kgf is applied to the magnet.

  On the other hand, in the conventional magnet holding method, the claw-shaped magnetic pole itself tries to hold the centrifugal force applied to the magnet. In this magnet holding method, it is necessary to finish the surfaces to which both the magnet and the claw portion are joined with extremely high precision so that both are in surface contact. That is, when both contact each other around a point, local stress concentrates on the magnet, and the magnet is damaged. And since it is difficult to increase the machining accuracy of magnets in mass-produced products, it is possible to take measures to ensure the external accuracy of magnets with a SUS plate or resin mold instead, but the cost is enormous. Connected.

Further, for the convenience of winding the field coil, the pole cores are divided into two parts divided in the axial direction, but it is necessary to improve the combination accuracy. Ensuring the accuracy of these parts actually increases the cost of mass production of the rotor significantly.
Furthermore, even if such a static shape accuracy is devised, it is still difficult to hold the magnet in the vehicle alternator.
That is, the vehicle alternator is placed in a high temperature environment of hundreds of degrees Celsius because it is arranged in the engine room, and generates a displacement of several tens of μm due to thermal expansion / contraction.

  In addition, a large centrifugal force is applied to the claw-shaped magnetic pole even when the magnet is not held, and the claw tip swells to the outer peripheral side by about 50 to 100 μm. Then, as the engine speed increases or decreases, the claw-shaped magnetic pole is displaced so as to flutter. Since the claw-shaped magnetic poles have a cantilever structure, the displacement is large at the tip, small on the claw root side, and the distance between adjacent claw-shaped magnetic poles also changes.

Therefore, even if there is a dynamic displacement of the heat and centrifugal force of the claw-shaped magnetic pole, if the magnet is to be held on a uniform surface, the magnet holding structure requires a great deal of effort.
Further, since the magnet body or the cover for protecting the magnet is slidably worn due to the displacement of the claw-shaped magnetic pole, it is necessary to ensure strength reliability for a long time.

  From these facts, in order to hold the magnet on the claw-shaped magnetic pole against the centrifugal force acting on the magnet, it is currently necessary to further devise, and it is desirable to hold the magnet other than the claw-shaped magnetic pole. . Therefore, in order to avoid the influence due to the relative displacement between the magnet and the claw-shaped magnetic pole in holding the magnet, the conventional improvement in which the magnet magnetized in the radial direction is arranged on the outer peripheral side of the yoke part at the shaft end of the Landel pole core. A type of magnet holding structure has been proposed (see, for example, Patent Document 5).

(2) Induced voltage in no-load no-excitation However, the above-described conventional improved magnet holding structure has a problem of an induced voltage in no-load no-excitation.
In this conventional improved magnet holding structure, since the magnet is arranged near the surface of the rotor, the main magnetic flux or leakage magnetic flux of the magnet does not close in the rotor, and the component directly linked to the stator Will have.

  Even at the leakage magnetic flux level, it is designed to generate a magnetic flux equivalent to about 1 to 2 V in an engine idling region of about 500 rpm. However, since the engine for automobiles has a variable speed range of about 1:10, for example, when the maximum engine speed is 10 times the idling, the induced voltage of the magnet of 1 to 2 V exceeds the vehicle system voltage, It adversely affects on-vehicle equipment. In order to suppress this, a so-called reverse field is required in which the field power supply is bipolar, and the field current is reversed at high speed to weaken the magnetic flux. When the direction of current flow is from one direction to two directions, there is a problem that the circuit is not a simple chopper control but a double circuit in which an H-type bridge is assembled, the number of elements increases, and the product cost increases. In addition, unlike the normal field, this reverse field must be quickly raised in response to an increase in engine speed, but the field has a high impedance of several hundred turns so that it can be controlled with a current as low as several A. Therefore, it is difficult to flow a reverse field current instantaneously. If the number of field turns is reduced to avoid this, the current value of the control power supply itself increases, the control element capacity increases, and a new problem arises that the product cost increases.

(3) Magnet Demagnetization by High Frequency Magnetic Field Induced by Stator Slot Since the slot harmonic magnetic flux has a frequency component of the number of stator slots × number of rotations / second, it is a high frequency magnetic field of 2 to 3 KHz. In such a situation, when the magnet is held between the claw-shaped magnetic poles, or when the U-shaped magnet is fitted and held at the tip of the claw-shaped magnetic pole, a part of the magnet or the magnet holding bracket is attached from the stator side. Exposed to the rotor surface. And this exposed magnet or magnet holding metal fitting is induction-heated by the high frequency magnetic field by a slot harmonic. If even a part of the magnet is induction-heated and becomes locally high in temperature, there is a problem that heat is transferred to the entire magnet and the magnet is thermally demagnetized.
Similarly, in the conventional improved magnet holding structure, a part of the magnet or the magnet holding metal fitting is exposed on the rotor surface as viewed from the stator side, and there is a problem of thermal demagnetization of the magnet.

JP-A-61-85045 US Pat. No. 4,959,577 US Pat. No. 5,543,676 JP 2002-136004 A JP 2004-153994 A

As described above, in order to hold the permanent magnet on the Landel pole core, the reliability of holding the permanent magnet is improved, the induced voltage of no-load non-excitation is suppressed, and the magnet heat generated by the high-frequency magnetic field induced by the stator slot is increased. It is necessary to avoid demagnetization.
However, the above-described conventional magnet holding structure has not been put to practical use because sufficient measures against these three problems have not been achieved.

The present invention has been made to solve such a problem, and an object thereof is to obtain a rotating electrical machine having the following characteristics.
(1) The magnet can be easily held, and the displacement of the tip of the claw and the relative displacement between the claws that change greatly with respect to the centrifugal force do not directly affect the magnet holding.
(2) In an in-vehicle generator having a wide temperature range, the axial displacement between the claws with respect to the thermal expansion of the shaft and the rotor does not directly affect the magnet holding.
(3) Even if the magnet amount is increased considerably, it is difficult to generate an induced voltage with no load and no excitation.
(4) Inductive heating is difficult due to the entrance of the stator slot harmonic magnetic flux.
(5) The increase in the moment of inertia due to the addition of the magnet and the magnet holding material is small, and the inertia torque is difficult to generate.

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. Furthermore, a permanent magnet holding portion integrally projecting from the yoke portion at the portion of the pair of yoke portions facing the inner peripheral surface on the tip side of each of the plurality of claw-shaped magnetic pole portions, and the permanent magnet A cylindrical magnet holding hole which is formed in each holding portion with the hole center aligned in the axial direction and has an axial opening facing a portion of the inner peripheral wall facing the inner peripheral surface on the tip side of the claw-shaped magnetic pole portion. And a permanent magnet which is inserted and held in each of the magnet holding holes, and whose exposed portion from the axial opening opposes the inner peripheral surface on the tip side of the claw-shaped magnetic pole portion. Each of the permanent magnets is molded integrally with the exposed portion protruding from a cylindrical resin body fitted in the magnet holding hole, and has a direction opposite to the direction of the magnetic field formed by the field coil. Is magnetized.

According to this invention, the permanent magnet is held on the yoke part side. Therefore, since the displacement of the claw-shaped magnetic pole due to centrifugal force or thermal expansion does not affect the permanent magnet, the occurrence of cracks or chipping of the permanent magnet due to the displacement of the claw-shaped magnetic pole portion is suppressed. Further, since the permanent magnet is located on the inner diameter side of the claw-shaped magnetic pole portion, an increase in the moment of inertia accompanying the arrangement of the permanent magnet is reduced. Furthermore, the centrifugal force acting on the permanent magnet is reduced, and the permanent magnet can be easily held.
In addition, since the permanent magnet is inserted and held in a cylindrical magnet holding hole having an axial opening in a part of the inner peripheral wall, the permanent magnet can be easily held, and the magnet holding hole can be drilled, reamer, etc. The rotary cutting tool can be used simply and with high accuracy, and the permanent magnet can be held without rattling.
In addition, since the permanent magnet is arranged to face the inner peripheral surface on the tip side of the claw-shaped magnetic pole part, the permanent magnet is located on the inner diameter side of the claw-shaped magnetic pole part and is directly induction-heated by the stator slot harmonics. Therefore, it is possible to prevent thermal demagnetization.
Furthermore, since the permanent magnet is magnetized and oriented in the direction opposite to the direction of the magnetic field created by the field coil, the magnetic circuit by the permanent magnet is formed to close inside the rotor, generating an induced voltage with no load and no excitation. Is suppressed.

Embodiment 1 FIG.
FIG. 1 is a sectional view schematically showing an automotive alternator according to Embodiment 1 of the present invention, and FIG. 2 shows a rotor applied to the automotive alternator according to Embodiment 1 of the present invention. FIG. 3 is a perspective view for explaining the configuration of a permanent magnet mounted on a rotor applied to an automotive alternator according to Embodiment 1 of the present invention. FIG. 4 and FIG. FIG. 3 is a schematic diagram for explaining the flow of magnetic flux in the automotive alternator according to Embodiment 1;

  1 to 3, an AC generator 1 for a vehicle is supported by a case 4 formed of 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 end surfaces of the rotor 13 A fixed fan 7, a fixed gap with respect to the rotor 13, surrounding the outer periphery of the rotor 13, fixed to the case 4, and fixed to the rear side of the shaft 16; A pair of slip rings 8 for 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. 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, and a first boss portion 18 in which a shaft insertion hole is formed at an axial position, and extends radially outward from one end edge of the first boss portion 18. The thick yoke-shaped first yoke part 19 and the first claw-shaped magnetic pole part 20 extending from the outer periphery of the first yoke part 19 to the other axial end side. 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 in which a shaft insertion hole is drilled at an axial center position, and extends radially outward from the other end edge of the second boss portion 22. The thick ring-shaped second yoke portion 23 and the second claw-shaped magnetic pole portion 24 extending from the outer periphery of the second yoke portion 23 to one end in the axial direction are provided. 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 inserted through the shaft insertion hole. 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.

The 1st magnet holding base 30 as a permanent magnet holding part is integrally formed by the 1st pole core body 17 by the cold forging manufacturing method. The first magnet holding pedestal 30 is integrally projected on the outer peripheral surface of the first yoke portion 19 that faces the inner peripheral surface of the tip end side of each second claw-shaped magnetic pole portion 24. A cylindrical first magnet holding hole 31 is formed in the first magnet holding base 30 so that the hole center coincides with the axial direction. A first axial opening 32 that opens the first magnet holding hole 31 toward the second claw-shaped magnetic pole portion 24 is formed in the outer peripheral portion of the first magnet holding base 30 so as to extend from one axial direction to the other. Yes.
The first permanent magnet 33 is made into a cylindrical body having an outer wall surface shape that matches the inner wall surface shape of the first magnet holding hole 31, and is inserted and held in the first magnet holding hole 31 from the axial direction. At this time, the exposed portion of the first permanent magnet 33 from the first axial opening 32 is opposed to the inner peripheral surface on the front end side of the second claw-shaped magnetic pole portion 24.

The 2nd magnet holding base 34 as a permanent magnet holding part is integrally molded by the 2nd pole core body 21 by the cold forging manufacturing method. The second magnet holding pedestal 34 is integrally projected on the outer peripheral surface of the second yoke portion 23 that faces the inner peripheral surface of the front end side of each first claw-shaped magnetic pole portion 20. A cylindrical second magnet holding hole 35 is formed in the second magnet holding base 34 with the hole center aligned in the axial direction. A second axial opening 36 that opens the second magnet holding hole 35 toward the first claw-shaped magnetic pole portion 20 is formed in the outer peripheral portion of the second magnet holding base 34 so as to extend from one side in the axial direction to the other side. Yes.
The second permanent magnet 37 is formed into a cylindrical body having an outer wall surface shape that matches the inner wall surface shape of the second magnet holding hole 35, and is inserted and held in the second magnet holding hole 35 from the axial direction. At this time, the exposed portion of the second permanent magnet 37 from the second axial opening 36 opposes the inner peripheral surface on the tip side of the first claw-shaped magnetic pole portion 20.

  Further, in the first and second permanent magnets 33 and 37, the magnetization direction 38 is opposite to the direction of the magnetic field 39 generated in the plane in which the field current flowing through the field coil 14 is orthogonal to the axis of the rotor 13. It is so magnetized. That is, as shown in FIG. 1, when the field coil 14 is energized and the magnetic field 39 is generated in the direction of the arrow, the first and second permanent magnets 33 and 37 are magnetized in the opposite direction to the magnetic field 39. Is done. Here, the magnetization directions 38 of the first and second permanent magnets 33 and 37 coincide with the radial direction, and the first and second claw-shaped magnetic pole portions 20, the extension lines of the magnetization direction 38 face each other. 24 toward the inner peripheral surface on the tip side. In the case of a design in which the direction of the magnetic field 39 created by the field current flowing through the field coil 14 is reversed, the first and second permanent magnets 33 and 37 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.

Next, the operation of the magnetic flux will be described with reference to FIGS.
First, when the field coil 14 is energized, a magnetic flux 39a is generated. This magnetic flux 39 a enters the teeth portion of the stator core 11 from the first claw-shaped magnetic pole portion 20 through the air gap 40. Then, the magnetic flux 39a 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 40 from the tooth portion facing the adjacent second claw-shaped magnetic pole portion 24, and the second magnetic flux 39a. The claw-shaped magnetic pole part 24 is entered. Next, the magnetic flux 39a 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 thus the first claw-shaped magnetic pole portion. 20 is reached. 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 first embodiment, the first and second permanent magnets 33 and 37 are magnetized and oriented so as to be opposite to the direction of the magnetic field 39 generated by the field coil 14. Therefore, the direction of the magnetic field generated by the first and second permanent magnets 33 and 37 is opposite to the magnetic field 39 generated by the field coil 14. In order for the magnetic flux 41 generated from the first and second permanent magnets 33 and 37 to interlink with the stator core 11, it is necessary to reciprocate the air gap 40 having a large magnetic resistance. The first and second permanent magnets 33 and 37 are disposed on the inner diameter side of the second and first claw-shaped magnetic pole portions 24 and 20, and the first and second claw-shaped magnetic pole portions 20 and 24 It arrange | positions so that it may circulate with a shorter magnetic path length with respect to the surrounding surface side. Therefore, most of the magnetic flux 41 forms a magnetic circuit closed inside the rotor without detouring to the stator core 11.

That is, the magnetic flux 41 generated from the first permanent magnet 33 is transmitted from the first magnet holding base 30 to the first yoke portion 19, the first boss portion 18, the second boss portion 22, the second yoke portion 23, and the second claw. Return to the first permanent magnet 33 through the magnetic pole portion 24. Further, the magnetic flux 41 generated from the second permanent magnet 37 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 joint. It passes through the iron part 23 and the second magnet holding base 34 and returns to the second permanent magnet 37.
Therefore, the magnetic flux 41 generated by the first and second permanent magnets 33 and 37 is opposite to the magnetic flux 39a generated by the field coil 14, and the magnetic flux constituting the first and second pole core bodies 17 and 21 is reversed. The density can be greatly reduced and magnetic saturation can be eliminated.

  Next, using the vehicle alternator 1 configured as described above, the amount of stator interlinkage magnetic flux with respect to the field ampere turn (field AT) and the amount of power generation with respect to the rotational speed were measured. As shown in FIG. For comparison, a conventional device in which the first and second permanent magnets 33 and 37 are omitted is manufactured, and the amount of stator interlinkage magnetic flux with respect to the field ampere turn (field AT) and the amount of power generation with respect to the rotational speed (direct current). The current A) was measured and the results are shown in FIGS. In FIG. 6, the solid line indicates the product of the present invention, and the dotted line indicates the conventional apparatus.

From FIG. 6, the difference between the vehicle alternator 1 and the conventional device is small in the region where the field AT is small, and the difference between the vehicle alternator 1 and the conventional device is large when the region where magnetic saturation starts is exceeded. I understand that That is, it can be seen that the arrangement of the first and second permanent magnets 33 and 37 eliminates magnetic saturation and increases the amount of magnetic flux linked to the stator 10.
Similarly, it can be seen from FIG. 7 that the vehicular AC generator 1 can obtain a larger amount of power generation than the conventional device, particularly in the low-speed rotation region.

  That is, in the conventional device, 30% or more of the magnetomotive force of the field is consumed by the magnetic circuit of the rotor due to magnetic saturation, and it is difficult to increase the amount of magnetic flux. On the other hand, in this Embodiment 1, since magnetic saturation is eliminated as described above, it is presumed that the magnetic flux interlinked with the stator 10 is increased and the amount of power generation is increased. In particular, it was confirmed that the amount of power generation in the low-speed idling region where magnetic saturation is remarkable can be greatly increased.

  In the first embodiment, the first and second permanent magnets 33 and 37 are arranged so as to face the inner peripheral surfaces of the first and second claw-shaped magnetic pole portions 20 and 24. The first and second permanent magnets 33 and 37 are located radially inward with respect to the outer surface of the rotor 13. Therefore, the stator slot harmonics remain on the surface portions of the first and second claw-shaped magnetic pole portions 20 and 24 and do not act to directly induction heat the first and second permanent magnets 33 and 37. As a result, the first and second permanent magnets 33 and 37 are prevented from being heated and demagnetized.

  In addition, since the first and second permanent magnets 33 and 37 are disposed so as to face the inner peripheral surfaces of the first and second claw-shaped magnetic pole portions 20 and 24, the first and second permanent magnets 33 are disposed. , 37 becomes a magnetic circuit closed inside the rotor, and the magnetic flux component linked to the stator 10 is eliminated. Therefore, generation of the induced voltage of the first and second permanent magnets 33 and 37 during no-load no-excitation is suppressed. As a result, the magnet amount of the first and second permanent magnets 33 and 37 can be increased.

The first and second permanent magnets 33 and 37 are attached to the first and second yoke portions 19 and 23. Therefore, since the first and second permanent magnets 33 and 37 are positioned on the inner diameter side of the first and second claw-shaped magnetic pole portions 20 and 24, the centrifugal force applied to the first and second permanent magnets 33 and 37 is reduced. It becomes small and the holding structure of the 1st and 2nd permanent magnets 33 and 37 can be simplified. Further, since the first and second permanent magnets 33 and 37 are not affected by the first and second claw-shaped magnetic pole portions 20 and 24 that are largely displaced with respect to the centrifugal force, the first and second permanent magnets 33 and 37 are not affected. Is easy to hold. Further, even when applied to an in-vehicle generator having a wide temperature range, the first and second permanent magnets 33 and 37 are not affected by the axial displacement between the claw-shaped magnetic pole portions due to the thermal expansion of the rotor. The first and second permanent magnets 33 and 37 can be easily held. From these things, the reliability of holding | maintenance of the 1st and 2nd permanent magnets 33 and 37 is improved.
Further, since the first and second permanent magnets 33 and 37 are located on the inner diameter side of the first and second claw-shaped magnetic pole portions 20 and 24, the first and second permanent magnets 33 and 37 are disposed. The increase in the moment of inertia resulting from the above can be reduced, and the increase in the inertia torque can also be suppressed.

Next, the effect of the holding structure for the first and second permanent magnets 33 and 37 according to the first embodiment will be described.
The first and second magnet holding holes 31 and 35 are formed in a cylindrical shape in the first and second magnet holding bases 30 and 34 so that the hole direction coincides with the axial direction. The first and second magnet holding bases so that the first and second axial openings 32, 36 communicate the first and second magnet holding holes 31, 35 with the second and first claw-shaped magnetic pole portions 24, 20 side. 30 and 34. The first and second permanent magnets 33 and 37 formed in the outer wall-shaped cylindrical body that matches the inner peripheral wall shape of the first and second magnet holding holes 31 and 35 are held by the first and second magnets from the axial direction. The holes 31 and 35 are inserted and held.

  Therefore, since the hole shape of the first and second magnet holding holes 31, 35 is cylindrical, it can be easily formed by a cold forging method. Furthermore, the 1st and 2nd magnet holding holes 31 and 35 of a highly accurate hole dimension can be formed by giving a simple additional process with rotary cutting tools, such as a drill and a reamer, after shaping | molding. Further, since the first and second permanent magnets 33 and 37 are cylindrical bodies, they can be easily molded by a mold. Furthermore, the 1st and 2nd permanent magnets 33 and 37 of a highly accurate outer-diameter dimension can be formed by performing simple additional machining with rotary cutting tools, such as a drill and a reamer, after shaping | molding.

Thus, according to this magnet holding structure, the fitting surface can be produced by molding with a mold or cutting with a rotary cutting tool, and three-dimensional cutting using an NC machine or the like is not necessary, and manufacturing time is reduced. The manufacturing cost can be reduced while being shortened.
Further, since the fitting surface is a cylindrical surface, the processing accuracy can be increased, and the first and second permanent magnets 33 and 37 can be stably held in the first and second magnet holding holes 31 and 35 without rattling. It can hold firmly in the state. Therefore, even when vibrations from the automobile engine are applied to the vehicle alternator 1, the occurrence of cracks and chipping in the first and second permanent magnets 33 and 37 is suppressed. Further, even if the rotor 13 rotates at a high speed, a situation in which the first and second permanent magnets 33 and 37 come out of the first and second magnet holding holes 31 and 35 and are scattered is avoided.

In addition, since the contact surfaces of the first and second permanent magnets 33 and 37 and the first and second magnet holding holes 31 and 35 are cylindrical surfaces, there is no local stress concentration, and the first and second permanent magnets. Generation | occurrence | production of the damage of 33,37 and the 1st and 2nd magnet holding bases 30 and 34 is suppressed.
Furthermore, since the arrangement positions of the first and second permanent magnets 33 and 37 can be positioned with high accuracy, the first and second permanent magnets 33 and 37 and the first and second magnet holding holes can be obtained without lowering the output. Contact with 31, 35 can be avoided.

Embodiment 2. FIG.
FIG. 8 is a perspective view for explaining the configuration of a permanent magnet mounted on a rotor applied to an automotive alternator according to Embodiment 2 of the present invention, and FIG. 9 is a vehicle according to Embodiment 2 of the present invention. FIG. 10 is a schematic diagram for explaining the flow of magnetic flux in the automotive alternator according to Embodiment 2 of the present invention.

In FIG. 8, the permanent magnet 43 is formed into a columnar body having a trapezoidal cross section, and is molded with an insulating resin such as epoxy or nylon 66 so that the short side of the trapezoidal cross section protrudes. The resin body 44, which is a molded body of insulating resin, is formed into a cylindrical body having an outer peripheral wall shape that matches the inner peripheral wall shape of the first and second magnet holding holes 31, 35, except for the protruding portion of the permanent magnet 43. Has been. As shown in FIG. 9, the resin body 44 is inserted and held in the second magnet holding hole 35 from the axial direction. The protruding portion of the permanent magnet 43 from the resin body 44 extends from the second axial opening 36 of the second magnet holding hole 35 and is opposed to the inner peripheral surface on the tip side of the first claw-shaped magnetic pole 20. Although not shown, the resin body 44 in which the permanent magnet 43 is molded is inserted and held in the first magnet holding hole 31 from the axial direction.
Other configurations are the same as those in the first embodiment.

  In the second embodiment, the outer peripheral wall surface of the resin body 44 in which the permanent magnet 43 is molded serves as a fitting surface with the first and second magnet holding holes 31 and 35. Since the resin body 44 can be easily made into a cylindrical body with high dimensional accuracy compared to a permanent magnet, the cost can be reduced as compared with the first embodiment in which the permanent magnet is made into a cylindrical body.

  Further, since the non-magnetic resin body 44 is interposed between the permanent magnet 43 and the second magnet holding hole 35, a part of the magnetic flux of the permanent magnet 43 is held by the second magnet as shown in FIG. The leakage magnetic flux 45 leaking to the pedestal 34 and returning to the permanent magnet 43 decreases, and the amount of magnetic flux 46 toward the opposing first claw-shaped magnetic pole portion 20 increases. As a result, the magnetic flux inside the rotor is increased, the effect of relaxation of magnetic saturation is further enhanced, and the power generation amount of the vehicle AC generator can be further increased.

  Further, since the resin body 44 insulates the heat transmitted from the field coil 14 to the permanent magnet 43 via the first and second magnet holding bases 30 and 34, the temperature rise of the permanent magnet 43 can be suppressed. Therefore, even when a rare earth magnet is used as a magnet material that is easily demagnetized by heat, thermal demagnetization can be suppressed.

  In the second embodiment, the upper surface formed of the short side of the trapezoidal cross section of the permanent magnet 43 is formed in parallel to the inner peripheral surface on the tip side of the first and second claw-shaped magnetic pole portions 20 and 24 facing each other. You may do it. In this case, the gap between the permanent magnet and the claw-shaped magnetic pole part can be minimized.

Embodiment 3 FIG.
FIG. 11 is a diagram for explaining the configuration of a permanent magnet mounted on a rotor applied to an automotive alternator according to Embodiment 3 of the present invention.
In FIG. 11, a magnetic body 47 having an arcuate cross section made of iron or the like is bonded to the bottom surface of the permanent magnet 43 formed by the long side of the trapezoidal cross section. Then, the permanent magnet 43 is molded with insulating resin so that the short side of the trapezoidal cross section of the permanent magnet 43 protrudes and the magnetic body 47 is embedded. The resin body 48, which is a molded body of insulating resin, is formed into a cylindrical body having an outer peripheral wall shape that conforms to the inner peripheral wall shape of the first and second magnet holding holes 31, 35 except for the protruding portion of the permanent magnet 43. Has been.
Other configurations are the same as those in the second embodiment.

  In the third embodiment, the magnetic gap between the inner diameter side of the permanent magnet 43 and the first and second magnet holding bases 30 and 34 in the second embodiment is filled with the magnetic body 47, and the magnetic resistance can be reduced. . That is, the magnetic resistance of the magnet magnetic path is reduced, the amount of magnet magnetic flux is increased, the effect of relaxing the magnetic saturation of the rotor is increased, and the power generation output can be further increased.

Embodiment 4 FIG.
FIG. 12 is an exploded perspective view showing a rotor applied to an automotive alternator according to Embodiment 4 of the present invention.
In FIG. 12, a truncated conical second magnet holding hole 50 is formed in the second magnet holding base 34 with the hole center aligned in the axial direction. A second axial opening 51 that opens the second magnet holding hole 50 toward the first claw-shaped magnetic pole part 20 is formed in the outer peripheral part of the second magnet holding base 34 so as to extend from one side in the axial direction to the other side. Yes. The second permanent magnet 52 is made into a truncated cone having an outer wall shape that matches the inner wall shape of the second magnet holding hole 50, and is inserted and held in the second magnet holding hole 50 from the axial direction. At this time, the exposed portion of the second permanent magnet 52 from the second axial opening 51 faces the inner peripheral surface on the front end side of the first claw-shaped magnetic pole portion 20.

Here, although not shown, a truncated cone-shaped first magnet holding hole is formed in the first magnet holding base 30 with the hole center aligned in the axial direction. A first axial opening that opens the first magnet holding hole toward the second claw-shaped magnetic pole portion 24 is formed in the outer peripheral portion of the first magnet holding base 30 so as to extend from one axial direction to the other. The first permanent magnet is made into a truncated cone having an outer wall shape that matches the inner wall surface shape of the first magnet holding hole, and is inserted and held in the first magnet holding hole from the axial direction. At this time, the exposed portion of the first permanent magnet from the first axial opening faces the inner peripheral surface of the distal end side of the second claw-shaped magnetic pole portion 24.
Other configurations are the same as those in the first embodiment.

Since the support structure of the first and second permanent magnets is the same, only the support structure of the second permanent magnet 52 will be described here.
Also in this Embodiment 4, since the 2nd magnet holding hole 50 is formed in the inner peripheral wall surface shape of the truncated cone shape, it can shape | mold easily by the cold forging manufacturing method. Furthermore, the 2nd magnet holding hole 50 of a highly accurate hole dimension can be formed by performing simple additional machining with rotary cutting tools, such as a drill and a reamer, after shaping | molding. Moreover, since the 2nd permanent magnet 52 is formed in the truncated cone, it can shape | mold easily by the cold forging manufacturing method. Furthermore, the 2nd permanent magnet 52 of a highly accurate hole dimension can be formed by performing simple additional machining with rotary cutting tools, such as a drill and a reamer, after shaping | molding.

In addition, since the fitting surface of the second magnet holding hole 50 and the second permanent magnet 52 is the outer peripheral surface of the truncated cone, just by inserting the second permanent magnet 52 into the second magnet holding hole 50 from the axial direction, The axial position of the second permanent magnet 52 with respect to the second magnet holding hole 50 can be accurately positioned at the design position.
Further, by making the angle with respect to the axial direction of the outer peripheral surface of the truncated cone of the second permanent magnet 52 substantially equal to the angle with respect to the axial direction of the inner peripheral surface on the tip side of the opposing first claw-shaped magnetic pole part 20, A gap between the second permanent magnet 52 and the first claw-shaped magnetic pole part 20 can be minimized.

  In the fourth embodiment, as in the second embodiment, a truncated cone resin body may be molded so that a part of the trapezoidal trapezoidal permanent magnet 43 protrudes. Furthermore, the magnetic body 47 may be joined to the bottom surface of the permanent magnet 43 as in the third embodiment.

Embodiment 5 FIG.
13 is a cross-sectional view schematically showing a configuration of a rotor applied to an automotive alternator according to Embodiment 5 of the present invention, and FIG. 14 is an automotive alternator according to Embodiment 5 of the present invention. It is principal part sectional drawing explaining the support structure of the permanent magnet in the rotor applied to FIG.

  In FIG. 13 and FIG. 14, the female screw portion 53 is engraved on the inner peripheral wall surface of the second magnet holding hole 50 on the large diameter side. The nonmagnetic ring 54 is made of thin stainless steel or epoxy resin, and is fitted on the large diameter side of the permanent magnet 52 in an externally fitted state. A male screw portion 55 is engraved on the outer peripheral wall surface of the nonmagnetic ring 54. The permanent magnet 52 is inserted and held in the second magnet holding hole 50 by fastening the male screw portion 55 to the female screw portion 53. The female screw portion 53 is engraved on the inner peripheral wall surface on the large diameter side of the first magnet holding hole, and the permanent magnet 52 is inserted into the first magnet holding hole by fastening the male screw portion 55 to the female screw portion 53. Is retained. Other configurations are the same as those in the fourth embodiment.

  Thus, since the permanent magnet 52 is held in the magnet holding hole by screwing the female screw portion 53 and the male screw portion 55, the axial dimensions of the first and second magnet holding bases are narrowed due to a processing error or the like. However, the holding strength of the permanent magnet 52 is increased, and the scattering of the permanent magnet 52 is prevented.

Here, in the fifth embodiment, the male screw portion is engraved in the non-magnetic ring and the female screw portion is engraved in the magnet holding hole. However, the female screw portion is engraved in the non-magnetic ring and the male screw is engraved. The part may be engraved in the magnet holding hole.
Further, although the fifth embodiment is described as being applied to a truncated conical permanent magnet, it may be applied to a cylindrical permanent magnet. That is, in the first embodiment, the non-magnetic ring in which the male screw portion is engraved is fitted into the first and second permanent magnets, and the female screw portion is engraved in the first and second magnet holding holes. The first and second permanent magnets may be inserted and held in the first and second magnet holding holes by fastening the portion to the female screw portion.

  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.

1 is a cross-sectional view schematically showing an automotive alternator according to Embodiment 1 of the present invention. It is a perspective view which shows the rotor applied to the alternating current generator for vehicles which concerns on Embodiment 1 of this invention. It is a perspective view explaining the structure of the permanent magnet mounted in the rotor applied to the alternating current generator for vehicles which concerns on Embodiment 1 of this invention. It is a schematic diagram for demonstrating the flow of the magnetic flux in the alternating current generator for vehicles which concerns on Embodiment 1 of this invention. It is a schematic diagram for demonstrating the flow of the magnetic flux in the alternating current generator for vehicles which concerns on Embodiment 1 of this invention. It is a figure showing the relationship between the field ampere turn (field AT) and stator interlinkage magnetic flux amount in the alternating current generator for vehicles concerning Embodiment 1 of this invention. It is a figure which shows the electric power generation amount with respect to the rotation speed in the alternating current generator for vehicles which concerns on Embodiment 1 of this invention. It is a perspective view explaining the structure of the permanent magnet mounted in the rotor applied to the alternating current generator for vehicles which concerns on Embodiment 2 of this invention. It is a front view which shows the rotor applied to the alternating current generator for vehicles which concerns on Embodiment 2 of this invention. It is a schematic diagram for demonstrating the flow of the magnetic flux in the alternating current generator for vehicles which concerns on Embodiment 2 of this invention. It is a figure explaining the structure of the permanent magnet mounted in the rotor applied to the alternating current generator for vehicles which concerns on Embodiment 3 of this invention. It is a disassembled perspective view which shows the rotor applied to the vehicle alternator which concerns on Embodiment 4 of this invention. It is sectional drawing which shows typically the structure of the rotor applied to the alternating current generator for vehicles which concerns on Embodiment 5 of this invention. It is principal part sectional drawing explaining the support structure of the permanent magnet in the rotor applied to the alternating current generator for vehicles which concerns on Embodiment 5 of this invention.

Explanation of symbols

  13 Rotor, 14 Field coil, 15 Pole core, 16 Shaft, 17 First pole core body, 18 First boss part, 19 First yoke part, 20 First claw-shaped magnetic pole part, 21 Second pole core body, 22 First 2 bosses, 23 2nd yoke part, 24 2nd claw-shaped magnetic pole part, 30 1st magnet holding base (permanent magnet holding part), 31 1st magnet holding hole, 32 1st axial opening, 33 1st permanent Magnet, 34 Second magnet holding base (permanent magnet holding portion), 35 Second magnet holding hole, 36 Second axial opening, 37 Second permanent magnet, 38 Magnetizing direction, 43 Permanent magnet, 44 Resin body, 47 Magnetic Body, 48 resin body, 50 second magnet holding hole, 51 second axial opening, 52 second permanent magnet, 53 female thread portion, 54 non-magnetic ring, 55 male thread portion.

Claims (8)

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 In a rotating electrical machine including a rotor having a field coil housed in a space surrounded by a magnetic pole portion,
A permanent magnet holding portion integrally projecting from the yoke portion at a portion of the pair of yoke portions facing the inner peripheral surface on the tip side of each of the plurality of claw-shaped magnetic pole portions;
Each of the permanent magnet holding portions is formed in a cylindrical shape having a hole center aligned in the axial direction and having an axial opening facing a portion of the inner peripheral wall facing the inner peripheral surface on the tip side of the claw-shaped magnetic pole portion. A magnet holding hole,
A permanent magnet inserted and held in each of the magnet holding holes, and an exposed portion from the axial opening facing the inner peripheral surface on the tip side of the claw-shaped magnetic pole portion,
Each of the permanent magnets is integrally molded with the exposed portion protruding from a cylindrical resin body fitted in the magnet holding hole, and attached in the direction opposite to the direction of the magnetic field formed by the field coil. A rotating electrical machine characterized by being magnetically oriented. 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 In a rotating electrical machine including a rotor having a field coil housed in a space surrounded by a magnetic pole portion,
A permanent magnet holding portion integrally projecting from the yoke portion at a portion of the pair of yoke portions facing the inner peripheral surface on the tip side of each of the plurality of claw-shaped magnetic pole portions;
A truncated cone formed in each of the permanent magnet holding portions with the hole center aligned in the axial direction and having an axial opening opposed to the inner peripheral surface on the tip side of the claw-shaped magnetic pole portion in a part of the inner peripheral wall Shaped magnet holding hole,
A permanent magnet inserted and held in each of the magnet holding holes, and an exposed portion from the axial opening facing the inner peripheral surface on the tip side of the claw-shaped magnetic pole portion,
Each of the permanent magnets is magnetized and oriented in a direction opposite to the direction of the magnetic field produced by the field coil. The rotating electrical machine according to claim 2 , wherein the permanent magnet is formed into a truncated cone fitted into the magnet holding hole. Angle relative to the axial direction of the outer peripheral surface of the truncated cone of the permanent magnet, according to claim 3, wherein the substantially equal to the inner peripheral surface angle relative to the axial direction of the distal end side of the claw-shaped magnetic pole portion opposed Rotating electric machine. 3. The rotating electrical machine according to claim 2 , wherein the permanent magnet is integrally molded with the exposed portion protruding from a frustoconical resin body fitted in the magnet holding hole. The outer wall surface of the exposed portion of the permanent magnet rotating electrical machine of claim 1 or claim 5, wherein the being formed substantially parallel to the said claw-shaped magnetic pole tip side of the inner peripheral surface of the opposing. An arc-shaped cross section of the magnetic body, the inner diameter side wall surface of the permanent magnet, according to claim 1 or claims are joined toward the circular arc cross sectional side on the inner diameter side, characterized in that it is molded integrally with the resin body Item 6. The rotating electric machine according to Item 5 . A non-magnetic ring is fitted to the permanent magnet in an externally fitted state, and a male screw portion and a female screw portion are formed so as to be able to be screwed to the inner peripheral wall surface of the magnet holding hole and the outer peripheral wall surface of the non-magnetic ring, 4. The rotating electrical machine according to claim 3, wherein the permanent magnet is inserted and held in the magnet holding hole by screwing the male screw portion and the female screw portion.

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