JP6894661B2 - Generator - Google Patents

Description

The present invention relates to a generator used for a bicycle hub dynamo or the like.

Since the rotor of a bicycle hub dynamo rotates at the same speed as the wheels, the rotation speed of the rotor tends to be slower than that of the roller dynamo, and the induced electromotive force at low speeds tends to be insufficient. .. Therefore, as the hub dynamo, a hub dynamo devised so that high-frequency AC power can be obtained even when the rotation speed of the rotor is low is preferably used.

As an example of this, Patent Document 1 proposes a claw pole type generator. This generator includes a stator and a rotor arranged on the outer peripheral side of the stator. The rotor has a plurality of magnets arranged side by side in the circumferential direction, and each magnet has magnetic poles facing the stator that are alternately different in the circumferential direction. The stator comprises a pair of stator cores arranged on both sides in the axial direction. Each stator core has a plurality of claws extending toward the side approaching each other, and the claws of the separate stator cores are provided so as to be alternately positioned in the circumferential direction. The claws of each stator core are arranged inside each magnet of the rotor in the radial direction, and the magnets are excited so that different polarities are alternately generated in the circumferential direction. An armature coil is arranged in the stator at a position where magnetic flux passes from the magnet through the claw portion of each stator core.

In this generator, the relative position of the magnet with respect to the claws of each stator core changes due to the rotation of the rotor, and the polarity of each claw is switched accordingly, so that the direction of the main magnetic flux interlinking the armature coil is changed. It reverses and an induced electromotive force is generated in the armature coil. Since the AC power obtained at this time has a frequency proportional to the number of poles of the magnet, it is easy to obtain a high frequency AC power corresponding to the number of poles of the magnet.

Japanese Unexamined Patent Publication No. 2007-94839

In recent years, in order to improve the design of bicycles, it has been required to reduce the outer diameter of the hub, and along with this, it is desired to reduce the outer diameter of the hub dynamo. In the claw pole type generator, the claws of the stator cores excited to have different polarities are arranged alternately in the circumferential direction. Therefore, as the outer diameter of the hub dynamo becomes smaller, the distance between adjacent claws becomes excessively small. As a result, the magnetic flux easily passes between the claws excited to have different polarities, and the leakage flux that does not interlink the armature coil tends to increase. Therefore, the claw pole type generator has a problem that the leakage flux increases as the outer diameter dimension is reduced, and it is difficult to obtain a sufficient induced electromotive force.

The present invention has been made in view of such a problem, and one of the objects thereof is that it is easy to obtain high-frequency AC power even when the rotation speed of the rotor is small, and further, it is suitable for miniaturization of the outer diameter dimension. It is to provide a generator.

A generator according to an aspect of the present invention includes a stator and a rotor arranged on the outer peripheral side or the inner peripheral side of the stator, and the rotor has magnetic poles facing the stator alternately in the circumferential direction. The stator has a plurality of magnets having different magnetic poles, and the stator is an stator core in which a plurality of first grooves are formed at intervals in the circumferential direction and an armature wound between the plurality of first grooves. The stator core has a coil, and the stator core has a first stator salient pole portion arranged between one first groove portion and a first groove portion adjacent to one in the circumferential direction, and one first groove portion. And a second stator salient pole portion arranged between the first groove portion adjacent to the other in the circumferential direction, and when the rotor rotates, the first stator salient pole portion and the second fixing The first state in which the magnetic poles of the magnets facing each of the child salient poles are different, and the magnetic poles of the magnets facing each of the first stator salient pole and the second stator salient pole are reversed from the first state. The positions of the magnet, the first stator salient pole portion and the second stator salient pole portion are determined so that the second state of the magnetic poles is alternately switched.

According to the present invention, it is easy to obtain high-frequency AC power even when the rotation speed of the rotor is small, and it is possible to obtain a generator suitable for miniaturization of the outer diameter dimension.

It is a partial side view which shows the bicycle on which the bicycle generator which concerns on 1st Embodiment is mounted. It is a front view which shows the structure of the hub and the surroundings of the bicycle which concerns on 1st Embodiment. It is sectional drawing which shows the generator for a bicycle which concerns on 1st Embodiment. It is sectional drawing which shows the armature coil of the bicycle generator which concerns on 1st Embodiment. It is a figure which shows the positional relationship of the magnet and the stator salient pole part which concerns on 1st Embodiment. It is a figure which shows the state which the electric angle of the generator which concerns on 1st Embodiment is zero. It is a figure which shows the state which the electric angle of the generator which concerns on 1st Embodiment is π / 2. It is a figure which shows the state which the electric angle of the generator which concerns on 1st Embodiment is π. It is a figure which shows the state which the electric angle of the generator which concerns on 1st Embodiment is 3π / 2. It is sectional drawing of the generator which concerns on 2nd Embodiment. It is sectional drawing which shows the armature coil of the generator which concerns on 2nd Embodiment. It is a figure which shows the state which the electric angle of the generator which concerns on 2nd Embodiment is zero. It is a figure which shows the state which the electric angle of the generator which concerns on 2nd Embodiment is π / 2. It is a figure which shows the state which the electric angle of the generator which concerns on 2nd Embodiment is π. It is a figure which shows the state which the electric angle of the generator which concerns on 2nd Embodiment is 3π / 2.

Hereinafter, in the description of each embodiment, the same components are designated by the same reference numerals, and duplicate description will be omitted. Further, in each drawing, for convenience of explanation, some of the components are omitted as appropriate.

[First Embodiment]
FIG. 1 is a partial side view showing a bicycle 12 on which a bicycle generator 10 (hereinafter, simply referred to as a generator 10) according to the first embodiment is mounted. The bicycle 12 includes a front fork 18 rotatably supported by the head tube 16 of the main frame 14, and a hub shaft 20 attached to the front fork 18. A front wheel 22 as a wheel is rotatably supported on the hub shaft 20. A headlight 24 is installed on the side of the front wheel 22, and the electric power obtained by the generator 10 is supplied to the headlight 24.

The front wheel 22 has a tubular hub 26 rotatably supported by a hub shaft 20 via a bearing (not shown), a plurality of spokes 28 attached to the outer peripheral portion of the hub 26, and an outer peripheral portion of each spoke 28. It also has a rim 30 to be attached. A tire 32 is attached to the rim 30.

FIG. 2 is a front view showing the configuration of the hub 26 and the surroundings of the bicycle 12. Configurations other than the hub 26 are shown by alternate long and short dash lines. A generator 10 serving as a hub dynamo is housed in the hub 26. Male threads 34 are formed at both ends of the hub shaft 20 in the axial direction. The hub shaft 20 is fixed to the front fork 18 together with the hub 26 by tightening the nuts 36 screwed into each male screw 34.

FIG. 3 is a cross-sectional view of the generator 10. This figure is a cross-sectional view orthogonal to the axial direction of the rotation center of the rotor 40, which will be described later, and is also a cross-sectional view taken along the line AA of FIG. In this figure, the hub 26 is omitted. Further, in the following description, the terms "axial direction", "circumferential direction", and "diameter direction" may be used in explaining the positional relationship of each component of the stator 38 and the rotor 40, which will be described later. .. Of these, the "axial direction" means the axial direction of the rotation center of the rotor 40, and the "circumferential direction" and the "diameter direction" mean the circumferential direction and the radial direction with respect to the rotation center of the rotor 40, respectively.

The generator 10 includes a stator 38 fixed to the hub shaft 20 and a rotor 40 rotatably supported by the hub shaft 20. The generator 10 is an outer rotor type generator in which the rotor 40 is arranged on the outer peripheral side of the stator 38. Further, the generator 10 is a synchronous generator. The rotor 40 is rotatably provided integrally with the hub 26 which is a part of the front wheel 22. The rotor 40 can rotate in conjunction with the rotation of the front wheels 22.

The rotor 40 forms an annular shape as a whole. The rotor 40 has a rotor core 46 including an annular base 42, and a plurality of magnets 48 arranged side by side in the circumferential direction of the rotor 40. The magnet 48 is bonded to the inner peripheral surface of the annular base 42 on the side facing the stator 38 by adhesion or the like. The rotor core 46 is not provided with a plurality of salient poles on the inner peripheral side of the annular base 42.

The magnet 48 is a permanent magnet. The magnet 48 is used for the field of the armature coil 60 described later. The radial direction of the magnet 48 is the magnetizing direction. In this figure, the direction from the south pole to the north pole in the magnet 48 is indicated by an arrow C. The magnet 48 is provided in a plate shape extending along the circumferential direction. A plurality of magnets 48 are provided so that the magnetic poles facing the stator 38 in the radial direction are alternately different magnetic poles in the circumferential direction. Each magnet 48 is configured so that the peripheral length w1 of the inner peripheral portion facing the stator 38 in the radial direction has the same size. The term "equivalent" here includes the case where they are completely the same and the case where they are substantially the same. The interpretation of "equivalent" is the same as follows.

The magnet 48 is arranged at a position shifted in the circumferential direction at an angle equivalent to a predetermined angle λ (hereinafter, also referred to as magnetic pole pitch). In this example, a total of 20 magnets 48 are provided, and a total of 20 magnetic poles facing the stator 38 are also provided. That is, an even number of these is provided. Further, the magnetic pole pitch λ is 18 ° (= 360 ° / 20). This magnetic pole pitch λ corresponds to the electric angle π of the generator 10, and when the rotor 40 rotates by the magnetic pole pitch λ × 2, the armature coil 60 generates AC power for one cycle as described later.

The stator 38 forms an annular shape as a whole. The stator 38 has a stator core 50 in which a plurality of first groove portions 52 are formed at intervals in the circumferential direction. The rotor core 46 and the stator core 50 are configured by laminating a plurality of metal plates in the axial direction of the rotor 40. This metal plate is made of a soft magnetic material such as an electromagnetic steel plate.

Each of the first groove portions 52 is arranged at a position shifted by an equivalent angle in the circumferential direction. In this example, a total of four first groove portions 52 are provided. The first groove portion 52 is formed so as to be recessed from the radial outer side on the side facing the rotor 40 to the radial inner side on the opposite side.

In addition to the first groove portion 52, the stator 38 includes an arc-shaped magnetic path connecting portion 54 adjacent to the bottom side of each first groove portion 52, and a magnetic path adjacent to both sides in the circumferential direction with respect to the first groove portion 52. It has parts 56A and 56B. The magnetic path connecting portion 54 connects the magnetic path portions 56A and 56B in the circumferential direction. The magnetic path portions 56A and 56B are one of the first magnetic path portions 56A adjacent to one of the circumferential directions (clockwise in the figure) of the first groove portions 52 arranged every other in the circumferential direction, and the other in the circumferential direction (the other in the circumferential direction). It has a second magnetic path portion 56B adjacent to the counterclockwise direction in the figure). The first magnetic path portion 56A and the second magnetic path portion 56B are alternately arranged in the circumferential direction. In this example, two first magnetic path portions 56A and two second magnetic path portions 56B are provided.

The magnetic path portions 56A and 56B are provided with a plurality of stator salient pole portions 62A and 62B that project outward in the radial direction on the side facing the rotor 40. The stator salient poles 62A and 62B are arranged with a predetermined gap with respect to the magnet 48. The peripheral length w2 of the tip portion of the stator salient poles 62A and 62B facing the rotor 40 in the radial direction is configured to be smaller than the inner peripheral peripheral length w1 of the magnet 48.

The stator salient poles 62A and 62B have two first stator salient poles 62A provided in the first magnetic path 56A and two second stator salient poles 62B provided in the second magnetic path 56B. And have. The first stator salient pole portion 62A and the second stator salient pole portion 62B are arranged in every other first groove portion 52 in the circumferential direction (for example, the first groove portion 52 on the upper side in the drawing and the first groove portion 52 on the lower side in the drawing. It is arranged at a position corresponding to the groove portion 52). Specifically, the first stator salient pole 62A has one first groove 52 (for example, the first groove 52 on the upper side in the drawing) and one of the circumferential directions (clockwise) arranged every other in the circumferential direction. It is arranged within the circumferential range between the first groove 52 (for example, the first groove 52 on the right side in the drawing) adjacent to the first groove 52 (direction). The second stator salient pole portion 62B is located between one first groove portion 52 and the first groove portion 52 (for example, the first groove portion 52 on the left side in the drawing) adjacent to the other in the circumferential direction (counterclockwise direction). It is placed within the circumferential range. In this example, two first stator salient poles 62A and two second stator salient poles 62B are provided alternately in the circumferential direction, and a total of four are provided respectively.

The second between the plurality of first stator salient poles 62A provided in one first magnetic path portion 56A and the plurality of second stator salient poles 62B provided in one second magnetic path portion 56B. A groove 64 is formed. The second groove portion 64 is formed so as to be recessed from the radial outer side on the side facing the rotor 40 to the radial inner side on the opposite side. The radial dimension of the second groove portion 64 is smaller than the radial dimension of the first groove portion 52. As a result, the radial dimensions of the magnetic path portions 56A and 56B at the portions adjacent to the bottom side of the second groove portion 64 are larger than those of the magnetic path connecting portion 54. As a result, as will be described later, when the armature coil 60 is wound around each of the magnetic path portions 56A and 56B, it becomes easy to secure the strength of the magnetic path portions 56A and 56B.

Further, the magnetic path portions 56A and 56B are formed so that the width in the circumferential direction increases toward the outer side in the radial direction on the side facing the rotor 40. As a result, when the armature coil 60 is wound around each of the magnetic path portions 56A and 56B, the armature coil 60 is less likely to come off from the magnetic path portions 56A and 56B in the radial direction.

The first groove portion 52 is provided to separate the first stator salient pole portion 62A and the second stator salient pole portion 62B in the circumferential direction. Further, the second groove portion 64 is provided to separate each of the plurality of first stator salient poles 62A and each of the plurality of second stator salient poles 62B in the circumferential direction.

FIG. 4 is a cross-sectional view showing the armature coil 60 of the generator 10. In this figure, the winding direction B of the armature coil 60 in one of the axial directions of the rotor 40 (the front side of the paper surface) is also shown. The stator 38 further includes an armature coil 60 that is wound between the plurality of first groove portions 52. The armature coil 60 is wound around either the first magnetic path portion 56A or the second magnetic path portion 56B provided between the first groove portions 52 adjacent to each other in the circumferential direction. At this time, the armature coil 60 is wound so as to straddle the plurality of first stator salient poles 62A or the plurality of second stator salient poles 62B in the circumferential direction. The armature coil 60 is wound so as to surround such a plurality of first stator salient poles 62A or a plurality of second stator salient poles 62B from both sides in the circumferential direction and both sides in the axial direction.

Since the armature coil 60 is housed in the space of the first groove 52 provided to separate the first stator salient pole portion 62A and the second stator salient pole portion 62B in this way, the armature is electric. The thickness dimension in the radial direction can be suppressed by the amount of the child coil 60.

The armature coil 60 is wound in a concentrated winding between the first groove portions 52 adjacent to each other in the circumferential direction, but may be wound in a distributed winding so as to pass through another first groove portion 52. The armature coils 60 adjacent to each other in the circumferential direction are wound in the winding directions B opposite to each other, but they may be wound in the same direction.

As will be described later, the armature coil 60 generates in-phase AC power when the rotor 40 rotates. Each armature coil 60 is electrically connected in parallel, its output end is connected to a rectifier circuit (not shown), and single-phase AC power is output to the rectifier circuit. The rectifier circuit rectifies and smoothes AC power to convert it into DC power, and then supplies this to the headlight 24 (see FIG. 1) as an external electric device. The armature coils 60 may be electrically connected in series.

FIG. 5 is a diagram showing the positional relationship between the magnet 48 and the stator salient poles 62A and 62B. In this figure, in order to distinguish a part of the plurality of magnets 48 and the stator salient poles 62A and 62B, alphabets such as (a) are added to the end of each code. The same may be shown in the following figure.

The plurality of first stator salient pole portions 62A provided in one first magnetic path portion 56A are positioned at positions shifted in the circumferential direction at an angle equivalent to λ × 2 in relation to the magnetic pole pitch λ of each magnet 48. Be placed. A plurality of second stator salient poles 62B provided in one second magnetic path portion 56B are also arranged at positions shifted in the circumferential direction at an angle equivalent to λ × 2. Further, the other second stator salient poles 62B adjacent to each other in the circumferential direction in the vicinity of the first stator salient pole 62A are arranged at positions shifted in the circumferential direction at an angle equivalent to λ × 3.

As a result, the first stator salient pole 62A is displaced in the circumferential direction at an angle equivalent to λ × 2n with respect to the other first stator salient pole 62A when n is a natural number of 1 or more. Placed in position. For example, the first stator salient pole portion 62A (a) is displaced in the circumferential direction by λ × 2 with respect to the other first stator salient pole portion 62A (b) adjacent to the clockwise direction, and the opposite of the first stator salient pole portion 62A (a). It is displaced in the circumferential direction by λ × 8 (= λ × 3 + λ × 2 + λ × 3) with respect to the other first stator salient poles 62A (f) adjacent to each other in the clockwise direction. Similarly, the second stator salient pole portion 62B is also arranged at a position shifted in the circumferential direction at an angle equivalent to λ × 2n with respect to the other second stator salient pole portion 62B.

Further, the second stator salient pole portion 62B is arranged at a position shifted in the circumferential direction at an angle equivalent to λ × (2n + 1) with respect to the first stator salient pole portion 62A. For example, the second stator salient pole portion 62B (h) is displaced by λ × 3 with respect to the first stator salient pole portion 62A (a) adjacent to the clockwise direction, and is adjacent to the first stator salient pole portion 62B (h) in the counterclockwise direction. It deviates from the first stator salient pole portion 62A (f) by λ × 5 (= λ × 2 + λ × 3).

The operation of the generator 10 described above will be described with reference to FIGS. 6 to 9. Each figure shows a state when the rotor 40 is rotated in the direction P by π / 2 at an electric angle. Further, in FIGS. 6 and 8, among the magnetic fluxes flowing through the rotor core 46 and the like, the flow of the main magnetic flux is mainly shown, and the flow of the leakage flux is omitted. Further, FIGS. 7 and 9 show the flow of the leakage flux. In the following, it is assumed that the electric angle is zero when the positional relationship is shown in FIG. 6, and that the electric angles are π / 2, π, and 3π / 2 in FIGS. 7 to 9. For convenience, one magnet 48 (a) is marked with a “◯”.

As shown in FIG. 6, when the electric angle is zero, the stator salient poles 62A and 62B face each other in the radial direction with the magnet 48 in the vicinity thereof, and overlap the magnet 48 over the entire width in the circumferential direction. It is in. At this time, the magnetic pole of the magnet 48 facing the first stator salient pole portion 62A is the N pole, and the magnetic pole of the magnet 48 facing the second stator salient pole portion 62B is the S pole. That is, the magnetic poles of the magnet 48 on which the first stator salient pole portion 62A and the second stator salient pole portion 62B face each other are different.

As a result, a magnetic flux flowing inward in the radial direction from the magnet 48 facing the outer side in the radial direction flows through each of the first stator salient poles 62A, and the magnetic flux is opposed to the outer side in the radial direction in each of the second stator salient poles 62B. A magnetic flux flows toward the magnet 48. As a result, a closed-loop magnetic path Mp is formed that passes through the first stator salient poles 62A and the second stator salient poles 62B on both sides of the first groove 52 in the circumferential direction. For example, the magnet 48 (b) passes through the first stator salient pole portion 62A (a) → the magnetic path connecting portion 54 (a) → the second stator salient pole portion 62B (h), and then the magnet 48 (s). Further, a magnetic path Mp that returns to the original magnet 48 (b) via the rotor core 46 is formed.

The magnetic path Mp is formed so as to interlink in each armature coil 60 in the radial direction. At this time, either a plurality of first stator salient poles 62A or a plurality of second stator salient poles 62B are provided between the first groove portions 52 adjacent to each other in the circumferential direction. Therefore, the magnetic fluxes generated from the different magnets 48 can be interlocked in the armature coil 60 straddling the plurality of stator salient poles 62A and 62B in the circumferential direction in the same direction.

As shown in FIG. 7, when the electric angle is π / 2, the stator salient poles 62A and 62B face each magnet 48 in the radial direction with two magnets 48 adjacent to each other in the circumferential direction in the vicinity thereof. On the other hand, it is in a position where it overlaps over half the width in the circumferential direction. The magnetic poles of these two magnets 48 are the north pole and the south pole.

As a result, a closed-loop magnetic path that folds back from one magnet 48 adjacent to each other in the circumferential direction toward the other magnet 48 via the stator salient poles 62A and 62B and the rotor core 46 facing each other. Mp is formed. This magnetic path Mp is formed so as not to interlink each armature coil 60.

As shown in FIG. 8, when the electric angle is π, each stator salient pole portion 62A faces the magnet 48 in the vicinity thereof in the radial direction and overlaps the magnet 48 over the entire width in the circumferential direction. is there. At this time, the magnetic pole of the magnet 48 facing the first stator salient pole portion 62A is the S pole, and the magnetic pole of the magnet 48 facing the second stator salient pole portion 62B is the N pole. That is, the magnetic poles of the magnet 48 in which the first stator salient pole portion 62A and the second stator salient pole portion 62B face each other are magnetic poles that are inverted from those when the electric angle is zero.

As a result, magnetic flux flowing inward in the radial direction from the magnet 48 facing the outer side in the radial direction flows through each of the second stator salient poles 62B, and faces outward in the radial direction in each of the first stator salient poles 62A. A magnetic flux flows toward the magnet 48. As a result, a closed-loop magnetic path Mp is formed that passes through the first stator salient poles 62A and the second stator salient poles 62B on both sides of the first groove 52 in the circumferential direction. For example, the magnet 48 (r) passes through the second stator salient pole portion 62B (h) → the magnetic path connecting portion 54 (a) → the first stator salient pole portion 62A (a), and then the magnet 48 (a). Further, a magnetic path Mp that returns to the original magnet 48 (r) via the rotor core 46 is formed.

The magnetic path Mp is formed so as to interlink in each armature coil 60 in the radial direction. At this time, in the magnetic path Mp, the direction in which the armature coil 60 is interlaced is opposite to that in the case where the electric angle is zero (see FIG. 6).

As shown in FIG. 9, when the electric angle is 3π / 2, each stator salient pole portion 62A faces the two magnets 48 adjacent to each other in the circumferential direction in the radial direction in the vicinity thereof, and with respect to each magnet 48. It is in a position where it overlaps over half the width in the circumferential direction. The magnetic poles of these two magnets 48 are the north pole and the south pole.

The state where the electric angle is zero as described above is defined as the first state, and the state where π is defined as the second state. In this case, the magnetic pole of the magnet 48 facing the first stator salient pole portion 62A and the magnetic pole of the magnet 48 facing the second stator salient pole portion 62B can be in either the first state or the second state. , Different magnetic poles. Further, these magnetic poles are the magnetic poles that are inverted from the first state in the second state.

As shown in FIG. 6, in one armature coil 60 (for example, armature coil 60 (b)), in the first state, magnetic paths Mp interlinking in one radial direction (inside) are formed. It is formed. Further, as shown in FIG. 8, in one armature coil 60, a magnetic path Mp interlinking toward the other (outside) in the radial direction is formed in the second state. Further, in another armature coil 60 (for example, armature coil 60 (a)) adjacent to one armature coil 60 in the circumferential direction, as shown in FIG. 6, in the first state, the diameter is A magnetic path Mp interlinking toward the other (outside) of the direction is formed. Further, as shown in FIG. 8, in the other armature coil 60, a magnetic path Mp that interlinks in one (inside) direction in the radial direction is formed in the second state. That is, when switching between the first state and the second state, the direction of the magnetic flux interlinking in each armature coil 60 in the radial direction is reversed, and alternating current is induced in each armature coil 60. Power is generated. At this time, the way of changing the magnetic path Mp formed in each armature coil 60 is the same, and AC power of the same phase is generated in each armature coil 60. In this way, in the generator 10, the positions of the plurality of magnets 48 and the plurality of stator salient poles 62A and 62B are determined so that the first state and the second state are alternately switched.

The operation and effect of the above generator 10 will be described.
Generally, the frequency f (Hz) of the generator satisfies the relationship of the following equation (1) between the rotation speed N (r / min) of the rotor and the number of poles P of the generator. The number of poles P of the generator here is the number of magnets 48 (20 magnets) in this embodiment.
N = 120 × f / P ・ ・ ・ (1)

The present inventor analyzed using the structure shown in FIG. In this analysis, the rotation speed N of the rotor 40 is set to 120 (r / min), the frequency f (Hz) of the power generated by each armature coil 60 is obtained, and the power of the frequency f corresponding to the number of magnets 48 is obtained. I checked if I could get it. As a result, the frequency f was required to be 20 (Hz), and it was confirmed from the equation (1) that the number of magnets 48 was the number of poles of the generator.

Therefore, in the generator 10 according to the present embodiment, the frequency of the induced electromotive force increases as the number of magnets 48 increases, and even when the rotation speed of the rotor 40 is small, it becomes easy to obtain high frequency AC power. Since the voltage of the induced electromotive force is proportional to the product of the magnetic flux interlinking the armature coil 60 and the frequency, the fact that a high frequency AC power can be obtained means that a high voltage AC power can be obtained. become.

Further, the first stator salient pole portion 62A and the second stator salient pole portion 62B are provided at positions sandwiching the first groove portion 52, and it becomes easy to separate them. Therefore, even if these are excited to different polarities by the magnet 48, it becomes easy to suppress the generation of leakage flux between the first stator salient pole portion 62A and the second stator salient pole portion 62B. Therefore, it becomes easy to reduce the outer diameter dimension of the rotor 40 and the stator 38 of the generator 10 while suppressing the generation of the leakage flux between them. The fact that the generation of leakage flux between the first stator salient pole portion 62A and the second stator salient pole portion 62B can be suppressed means that the reduction of the magnetic flux interlinking the armature coil 60 is suppressed. Therefore, it becomes easy to obtain a sufficient output voltage by the generator 10.

Since the armature coil 60 is housed in the space of the first groove 52 provided to separate the first stator salient pole portion 62A and the second stator salient pole portion 62B in this way, the armature is electric. The thickness dimension in the radial direction can be suppressed by the amount of the child coil 60.

Further, for example, in a three-phase AC generator in which an armature coil is wound around each of a plurality of salient poles of a stator as described in Japanese Patent Application Laid-Open No. 2012-182961, an electric machine is used as the number of magnetic poles of the rotor increases. The number of child coils increases, which leads to high cost and reduced assemblability. In this respect, in the present embodiment, in order to obtain high-frequency AC power, it is only necessary to increase the number of magnets 48 without increasing the number of armature coils 60, so that the number of parts can be reduced and the cost can be reduced. Good assembleability can be obtained.

Further, in the conventional claw pole type generator, the magnetic flux flowing from the magnet of the rotor to the claw portion of each stator core changes the direction in the axial direction in the claw portion and then flows toward the root portion of the claw portion. The magnetic path cross-sectional area orthogonal to the magnetic path direction (axial direction) of the claw portion is determined according to the radial thickness and the peripheral length of the claw portion. Here, when the outer diameter dimension is miniaturized without changing the shaft length of the generator, the claw portion of the stator core becomes thinner in the circumferential direction without changing the shaft length, and the gap surface facing the magnet becomes thinner. Moreover, as a result of the decrease in the thickness in the radial direction, the magnetic path cross-sectional area at the base of the claw portion becomes small. Therefore, the magnetic flux received by the claw portion of the stator core at the gap surface tends to be concentrated on the root portion of the claw portion having a small magnetic path cross-sectional area, and magnetic saturation is likely to occur at the root portion. As a result, it becomes difficult for the magnetic flux interlinking the armature coil to flow, and it becomes difficult for the generator to obtain a sufficient output voltage.

In this regard, in the generator 10 according to the present embodiment, the magnetic flux flows through the stator salient poles 62A and 62B of the stator core 50 in the radial direction instead of the axial direction. The magnetic path cross-sectional area orthogonal to the magnetic path direction (diameter direction) of the stator salient poles 62A and 62B is determined according to the axial length and the peripheral length of the stator salient poles 62A and 62B, and is outside the generator 10. It does not change easily even when the diameter is reduced. Therefore, even when the outer diameter of the generator 10 is reduced, the magnetic path cross-sectional areas of the stator salient poles 62A and 62B can be secured by increasing the axial length of the stator core 50. Therefore, even when the outer diameter of the generator 10 is miniaturized, the generation of magnetic saturation of the stator salient poles 62A and 62B can be suppressed, the decrease of the magnetic flux interlinking the armature coil 60 can be suppressed, and the generator 10 can be suppressed. This makes it easier to obtain a sufficient output voltage.

Further, a plurality of first stator salient poles 62A or a plurality of second stator salient poles 62B are provided between the first groove portions 52 adjacent to each other in the circumferential direction, and they are wound so as to straddle them in the circumferential direction. In the armature coil 60 to be rotated, magnetic fluxes generated from different magnets 48 can be interlocked in the same direction through the plurality of stator salient poles 62A and 62B. Therefore, the amount of change in the magnetic flux in the armature coil 60 can be increased as compared with interlinking the magnetic flux generated from the single magnet 48 in the armature coil 60, and it becomes easier to obtain high-voltage AC power.

Further, each first stator salient pole portion 62A is displaced from the other first stator salient pole portion 62A at an angle equivalent to λ × 2n, and each second stator salient pole portion 62B is displaced from the other first stator salient pole portion 62B by the first stator protrusion. It deviates from the pole 62A at an angle equivalent to λ × (2n + 1). Therefore, the relative positions of the stator salient poles 62A and 62B with respect to the magnet 48 are aligned, the way of changing the magnetic path Mp formed by the magnetic flux generated from each magnet 48 is matched, and the armature coils 60 are in phase with each other. It is possible to easily obtain AC power.

Further, since the stator core 50 and the rotor core 46 can be formed by laminating a plurality of metal plates, iron loss due to eddy current in a portion through which the main magnetic flux passes can be greatly suppressed.

[Second Embodiment]
FIG. 10 is a cross-sectional view showing the generator 10 according to the second embodiment, and FIG. 11 is a cross-sectional view showing the armature coil 60 of the generator 10. In the example of FIG. 3, a total of 20 magnets 48 of the rotor 40 are provided, but in this example, a total of 22 magnets are provided. The magnetic pole pitch λ is about 16.36 ° (= 360 ° / 22). In the example of FIG. 3, two first stator salient poles 62A and two second stator salient poles 62B are provided in the first magnetic path portion 56A and the second magnetic path portion 56B, but in this example, they are provided. Five each are provided. As described above, the number of magnets 48 and stator salient poles 62A and 62B is not particularly limited.

The operation of the generator 10 described above will be described with reference to FIGS. 12 to 15. Each figure shows a state when the rotor 40 is rotated in the direction P by π / 2 at an electric angle. In FIGS. 12 and 14, among the magnetic fluxes flowing through the rotor core 46 and the like, the flow of the main magnetic flux is mainly shown, and the flow of the leakage flux is omitted. Further, FIGS. 13 and 15 show the flow of the leakage flux. In the following, it is assumed that the electric angle is zero when the positional relationship is shown in FIG. 12, and that the electric angles are π / 2, π, and 3π / 2 in FIGS. 13 to 15.

As shown in FIG. 12, when the electric angle is zero, the stator salient poles 62A and 62B face the magnet 48 in the vicinity in the radial direction and overlap the magnet 48 over the entire width in the circumferential direction. In position. As a result, as in the first embodiment, a closed loop magnetic path Mp passing through the first stator salient poles 62A and the second stator salient poles 62B on both sides in the circumferential direction sandwiching the first groove 52 is formed. Will be done.

As shown in FIG. 13, when the electric angle is π / 2, the stator salient poles 62A and 62B face each magnet 48 in the radial direction with two magnets 48 adjacent to each other in the circumferential direction in the vicinity thereof. On the other hand, it is in a position where it overlaps over half the width in the circumferential direction. As a result, as in the first embodiment, one magnet 48 adjacent to each other in the circumferential direction is directed toward the other magnet 48 via the stator salient poles 62A and 62B and the rotor core 46 facing each other. A closed-loop magnetic path Mp that folds back is formed.

As shown in FIG. 14, when the electric angle is π, the stator salient poles 62A and 62B face the magnet 48 in the vicinity in the radial direction and overlap the magnet 48 over the entire width in the circumferential direction. In position. As a result, as in the first embodiment, a closed loop magnetic path Mp passing through the first stator salient poles 62A and the second stator salient poles 62B on both sides in the circumferential direction sandwiching the first groove 52 is formed. Will be done.

As shown in FIG. 15, when the electric angle is 3π / 2, the stator salient poles 62A and 62B face each magnet 48 in the radial direction with two magnets 48 adjacent to each other in the circumferential direction in the vicinity thereof. On the other hand, it is in a position where it overlaps over half the width in the circumferential direction. As a result, a magnetic path Mp similar to that when the electric angle is π / 2 is formed.

As shown in FIG. 12, in one armature coil 60 (for example, armature coil 60 (b)), in the first state, magnetic paths Mp interlinking toward one (inside) in the radial direction are formed. It is formed. Further, as shown in FIG. 14, in one armature coil 60, a magnetic path Mp interlinking toward the other (outside) in the radial direction is formed in the second state. Further, in another armature coil 60 (for example, armature coil 60 (a)) adjacent to one armature coil 60 in the circumferential direction, as shown in FIG. 12, in the first state, the diameter is A magnetic path Mp interlinking toward the other (outside) of the direction is formed. Further, as shown in FIG. 14, in the other armature coil 60, a magnetic path Mp that interlinks in one (inside) direction in the radial direction is formed in the second state. Similar to the first embodiment, when switching between the first state and the second state, the direction of the magnetic flux interlinking in each armature coil 60 in the radial direction is reversed, and each armature coil 60 is switched. Induced electromotive force of alternating current is generated in. At this time, the way of changing the magnetic path Mp formed in each armature coil 60 is the same, and in-phase AC power is generated in each armature coil 60.

The present inventor also analyzed the above generator 10 using the structure shown in FIG. In this analysis, the rotation speed N of the rotor 40 is set to 120 (r / min), the frequency f (Hz) of the power generated by each armature coil 60 is obtained, and it corresponds to the number of magnets 48 (22 magnets). It was confirmed whether the power of the frequency f could be obtained. As a result, the frequency f was required to be 22 (Hz), and it was confirmed from the equation (1) that the number of magnets 48 was the number of poles of the generator.

Therefore, also in the generator 10 according to the present embodiment, as in the first embodiment, the frequency of the induced electromotive force increases as the number of magnets 48 increases, and even when the rotation speed of the rotor 40 is small, a high frequency alternating current It becomes easier to obtain power. In other respects as well, the same effect as that of the first embodiment can be obtained.

Although the present invention has been described above based on the embodiments, the embodiments merely show the principles and applications of the present invention. Further, in the embodiment, many modifications and arrangements can be changed without departing from the idea of the present invention defined in the claims.

The generator 10 has been described by taking a bicycle generator as an example, but its use is not limited to this. Further, when the generator 10 is a bicycle generator 10, it is sufficient that the rotor 40 can rotate in conjunction with the rotation of the rotating portion of the bicycle 12. Although the front wheel 22 as a wheel has been described as an example of the rotating portion here, the pulley of the rear derailleur (chain tensioner) may be used in addition to the hub shell and the crank. Further, the generator 10 may be configured as a roller dynamo or the like instead of a hub dynamo. Although the generator 10 is an outer rotor type generator, it may be an inner rotor type generator in which the rotor 40 is arranged on the inner peripheral side of the stator 38.

10 ... Generator, 12 ... Bicycle, 22 ... Front wheel (rotating part), 26 ... Hub, 38 ... Stator, 40 ... Rotor, 48 ... Magnet, 50 ... Stator core, 52 ... First groove, 60 ... Electric Child coil, 62A ... 1st stator salient pole, 62B ... 2nd stator salient pole.

Claims (5)

Stator and
A rotor arranged on the outer peripheral side of the stator is provided.
The rotor has a plurality of magnets in which the magnetic poles facing the stator are alternately different magnetic poles in the circumferential direction.
The stator has a stator core in which a plurality of first groove portions are formed at intervals in the circumferential direction, and an armature coil wound between the plurality of first groove portions.
The stator core includes a plurality of first stator salient poles arranged between one first groove portion and one adjacent first groove portion in the circumferential direction, and the one first groove portion. It has a plurality of second stator salient poles arranged between the first groove portions adjacent to the other in the circumferential direction.
When the rotor rotates, the first state in which the magnetic poles of the magnets facing the first stator salient pole portion and the second stator salient pole portion are different, and the first stator salient pole portion and the said The magnet, the first stator salient pole portion and the said The position of the second stator salient pole is determined,
The plurality of magnets have an individual magnet having a first polarity facing the adjacent first stator salient poles and facing the adjacent second stator salient poles when in the first state. Includes separate magnets of second polarity that are different from the first polarity,
The armature coil straddles the first armature coil Ru wound so as to straddle the first stator salient pole of multiple circumferentially, a plurality of the second stator salient pole portions in the circumferential direction There is a second armature coil that is wound like this,
Of the plurality of first stator salient poles, the first stator salient poles on both ends in the circumferential direction have a side surface on which one of the first armature coils comes into contact.
The side surface of the first stator salient pole portion extends linearly from the tip end portion of the first stator salient pole portion to the bottom side of the first groove portion.
Of the plurality of second stator salient poles, the second stator salient poles on both ends in the circumferential direction have a side surface on which one of the second armature coils comes into contact.
Wherein the side surface of the second stator salient pole portion, the generator characterized by Rukoto extends linearly from the tip of the second stator salient pole portion to the bottom side of the first groove. The plurality of magnets are arranged at positions shifted in the circumferential direction at an angle equivalent to a predetermined angle λ.
The first stator salient pole portion is arranged at a position shifted in the circumferential direction at an angle equivalent to λ × 2n (n is a natural number of 1 or more) with respect to the other first stator salient pole portion.
The second stator salient pole section to claim 1, characterized in that it is arranged at a position shifted in the circumferential direction with equal angles with lambda × respect to the first stator salient pole (2n + 1) The generator described. The generator according to claim 1 or 2 , wherein the stator core is formed by laminating a plurality of metal plates in the axial direction of the rotation center of the rotor. Generator according to any one of claims 1-3, wherein the rotor in conjunction with the rotation of the rotating portion of the bicycle is characterized in that it is a generator for a rotatable bicycle. Generator according to claim 4, characterized in that a hub dynamo bicycle.

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