CN105871092A - Generator - Google Patents

Abstract

The present invention provides a generator which can easily obtain high-frequency alternating current even when the rotational speed of the rotor is small, and is suitable for miniaturization of the outer diameter. The stator has a plurality of magnets, a first stator core, a second stator core and an armature winding, and the first stator core and the second stator core have: winding slots, in a circumferential direction relative to the winding slots The first stator salient pole portion of the magnetic circuit portion adjacent to one side, and the second stator salient pole portion of the magnetic circuit portion adjacent to the other side in the circumferential direction relative to the winding slot portion, the rotor salient pole portion and the stator The positions of the salient pole parts (62A), (62B) are determined to alternately switch between the first state and the second state, in the first state, the rotor with the first stator salient pole part (62A) and the rotor (40) Compared with the first reluctance between the salient pole parts, the second reluctance between the second stator salient pole part (62B) and the rotor salient pole part is larger, and in the second state, the first reluctance is larger than the first reluctance Two reluctance.

Description

dynamo

technical field

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

Background technique

The rotor of the hub dynamo of a bicycle rotates at the same speed as the wheel. Therefore, the rotation speed of the rotor tends to be slower than that of the roller dynamo, and the induced electromotive force tends to be insufficient when traveling at low speed. Therefore, it is preferable to use a structure designed to obtain high-frequency alternating current even when the rotational speed of the rotor is small for the hub dynamo.

As one of such examples, in Patent Document 1, a claw pole generator is proposed. 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 in a row in the circumferential direction, and the magnetic poles of the magnets facing the stator change alternately in the circumferential direction. The stator includes a pair of stator cores arranged on both sides in the axial direction. Each stator core is provided to have a plurality of claws extending toward a side close to each other, and positions of the claws of each stator core alternate in a circumferential direction. The claws of the respective stator cores are disposed radially inward of the respective magnets of the rotor, and are magnetized by the magnets so that polarities alternately change in the circumferential direction. In the stator, armature windings are arranged at positions through which magnetic flux passes from the magnets through the claws of the stator cores.

In this generator, the relative position of the claws of the magnets to the respective stator cores is changed by the rotation of the rotor, and the polarity of the claws is accordingly switched, thereby reducing the interlinkage in the armature winding. The direction of the main flux is reversed, which induces an electromotive force in the armature winding. Since the alternating current obtained at this time has a frequency proportional to the number of poles of the magnet, it is easy to obtain high-frequency alternating current corresponding to the number of poles of the magnet.

prior art literature

Patent Document 1: Japanese Patent Laid-Open No. 2007-49839.

In recent years, miniaturization of the outer diameter of the hub has been demanded in order to improve the exterior design of the bicycle, and accordingly, the miniaturization of the outer diameter of the hub dynamo has been desired. In the claw pole generator, the claw portions of the respective stator cores magnetized to different polarities are arranged alternately in the circumferential direction. Accordingly, as the outer diameter of the hub dynamo decreases, the distance between adjacent claw portions becomes too small. As a result, magnetic flux easily passes between the claw portions magnetized to different polarities, and leakage magnetic flux that does not interlink in the armature winding tends to increase. Therefore, in the claw pole generator, there is a problem that leakage magnetic flux increases as the outer diameter decreases, making it difficult to obtain sufficient induced electromotive force.

Contents of the invention

The present invention has been made in view of such problems, and one of its objects is to provide a generator that can easily obtain high-frequency alternating current even when the rotational speed of the rotor is small, and is suitable for miniaturization of the outer diameter.

A generator according to a certain aspect of the present invention includes: a rotor; and a stator including: a plurality of magnets arranged at intervals in the circumferential direction, and magnetic poles opposed to each other in the circumferential direction have the same polarity; a stator core, The stator core includes winding slots arranged on both sides of the magnet in the circumferential direction; and an armature winding wound between the winding slots so as to straddle the magnets in the circumferential direction, the rotor has a rotor core, The rotor core includes a plurality of rotor salient pole portions formed at intervals in the circumferential direction, and the stator core has a first stator salient pole portion and a magnetic circuit adjacent to the winding slot portion in the circumferential direction. and the second stator salient pole portion is provided opposite to the rotor at the magnetic circuit portion adjacent to the other side of the winding slot in the circumferential direction.

Invention effect

According to the present invention, it is possible to obtain a generator that can easily obtain high-frequency alternating current even when the rotational speed of the rotor is small, and is suitable for downsizing the outer diameter.

Description of drawings

FIG. 1 is a partial side view showing a bicycle equipped with a bicycle generator according to a first embodiment.

Fig. 2 is a front view showing the structure of the hub and its surroundings of the bicycle according to the first embodiment.

Fig. 3 is a cross-sectional view showing the bicycle generator of the first embodiment.

4 is a cross-sectional view showing an armature winding of the bicycle generator of the first embodiment.

5 is a diagram showing the positional relationship between a rotor salient pole portion and a stator salient pole portion in the first embodiment.

FIG. 6 is a diagram showing a state where the electrical angle of the generator in the first embodiment is zero.

7 is a diagram showing a state where the electric angle of the generator according to the first embodiment is π/2.

8 is a diagram showing a state where the electrical angle of the generator according to the first embodiment is π.

FIG. 9 is a diagram showing a state where the electrical angle of the generator according to the first embodiment is 3π/2.

Fig. 10 is a cross-sectional view of the generator of the second embodiment.

11 is a cross-sectional view showing an armature winding of a generator according to a second embodiment.

FIG. 12 is a diagram showing a state where the electric angle of the generator of the second embodiment is zero.

13 is a diagram showing a state where the electrical angle of the generator of the second embodiment is π/2.

Fig. 14 is a diagram showing a state where the electrical angle of the generator according to the second embodiment is π.

FIG. 15 is a diagram showing a state where the electric angle of the generator of the second embodiment is 3π/2.

Explanation of reference signs

10...generator

12…bicycle

22...Front wheel (rotating part)

26…Wheels

38…Stator

40…rotor

44...Rotor salient pole part

46…Rotor core

48…Magnet

50A...First stator core

50B…Second stator core

52...Winding slot

56A...The first magnetic circuit part

56B...Second magnetic circuit part

60...armature winding

62A...Salient pole part of the stator

62A...The first stator salient pole part

62B...The second stator salient pole part.

detailed description

Hereinafter, in the description of each embodiment, the same reference numerals are attached to the same components, and overlapping descriptions are omitted. In addition, in each drawing, for convenience of description, some components are appropriately omitted.

[first embodiment]

1 is a partial side view showing a bicycle 12 equipped with a bicycle generator 10 (hereinafter simply referred to as a generator 10 ) according to a first embodiment. The bicycle 12 has a front fork 18 rotatably supported by a head tube 16 of a main frame 14 , and a hub axle 20 attached to the front fork 18 . A front wheel 22 serving as a wheel is rotatably supported on the hub axle 20 . Headlights 24 are provided beside the front wheels 22 , and electric power obtained by the generator 10 is supplied to the headlights 24 .

The front wheel 22 further includes a cylindrical hub 26 rotatably supported by the hub axle 20 via a bearing (not shown), a plurality of spokes 28 attached to the outer periphery of the hub 26 , and a spoke 28 attached to the outer periphery of each spoke 28 . Rim 30. Tires 32 are mounted on the rim 30 .

FIG. 2 is a front view showing a hub 26 of the bicycle 12 and the surrounding configuration. Configurations other than the hub 26 are indicated by dashed-two dotted lines. The generator 10 serving as a hub generator is accommodated in the hub 26 . External threads 34 are formed at both ends in the axial direction of the hub shaft 20 . The hub axle 20 is fixed to the front fork 18 together with the hub 26 by tightening nuts 36 screwed with the respective external threads 34 .

FIG. 3 is a cross-sectional view of the generator 10 . This figure is a cross-sectional view perpendicular to the axial direction of the rotation center of the rotor 40 to be described later, and is also a cross-section taken along line A-A of FIG. 2 . In addition, the hub 26 is omitted in this figure. In addition, in the following description, the terms "axial direction", "circumferential direction", and "radial direction" may be used when describing the positional relationship of each component element of the stator 38 and the rotor 40 mentioned later. The “axial direction” here means the axial direction of the rotation center of the rotor 40 , and the “circumferential direction” and “radial direction” respectively mean the circumferential direction and the radial direction with respect to the rotation center of the rotor 40 .

The generator 10 includes a stator 38 fixed to the hub shaft 20 , and a rotor 40 rotatably supported on the hub shaft 20 . The generator 10 is an outer rotor generator in which a rotor 40 is disposed on the outer peripheral side of a stator 38 . Also, the generator 10 is a synchronous generator. The rotor 40 is provided to be rotatable 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 wheel 22 .

The rotor 40 is formed in a ring shape as a whole. The rotor 40 has a rotor core 46 including an annular base portion 42 and a plurality of rotor salient pole portions 44 provided on the side of the annular base portion 42 opposite to the stator 38 , that is, on the side of the annular base portion 42 . Inner peripheral side.

Each rotor salient pole portion 44 protrudes from the annular base portion 42 toward the radially inner side that is the side facing the stator 38 . Each rotor salient pole portion 44 has a width equal to the predetermined width w. The so-called "equal" here includes exactly the same situation and approximately the same situation. The interpretation of "equal" is also the same below.

The rotor salient pole portions 44 are arranged at intervals at positions shifted in the circumferential direction by an angle equal to a predetermined angle λ (hereinafter also referred to as a salient pole pitch). In this example, a total of 20 rotor salient pole portions 44 are provided, and the salient pole pitch λ is set to 18° (=360°/20). The salient pole pitch λ corresponds to the electrical angle 2π of the generator 10, and when the rotor 40 rotates the salient pole pitch λ, one cycle of alternating current is generated by the armature winding 60 as will be described later.

The stator 38 is formed in a ring shape as a whole. The stator 38 has a plurality of magnets 48 arranged at intervals in the circumferential direction, and a plurality of stator cores 50A, 50B arranged one at a time between the plurality of magnets 48 . The plurality of magnets 48 and the plurality of stator cores 50A, 50B are arranged alternately in the circumferential direction, and joined by adhesive or the like to form a ring shape. In this example, a total of four magnets 48 and stator cores 50A and 50B are provided, that is, an even number.

The magnet 48 is a permanent magnet. The magnet 48 is used for the magnetic field of the armature winding 60 mentioned later. The circumferential direction of the magnet 48 is the magnetization direction. The magnets 48 are arranged at intervals at positions shifted by an equal angle in the circumferential direction. The circumferentially facing magnetic poles of the plurality of circumferentially adjacent magnets 48 have the same polarity. The magnet 48 is provided in the shape of a plate extending in the radial direction so that the circumferentially adjacent stator cores 50A, 50B are separated in the radial direction.

The stator cores 50A, 50B and the above-mentioned rotor core 46 are formed by laminating a plurality of metal plates in the axial direction of the rotor 40 . The metal plate is made of a soft magnetic material such as an electromagnetic steel plate.

The stator cores 50A, 50B include: a first stator core 50A, and a magnet 48 arranged every other in the circumferential direction (for example, the magnet 48 on the upper side in the figure) on one side of the circumferential direction (clockwise direction in the figure). ) adjacent to; and the second stator core 50B adjacent to the one magnet 48 on the other side in the circumferential direction (counterclockwise in the figure). In this example, two first stator cores 50A are provided, and two second stator cores 50B are provided.

Each stator core 50A, 50B has the winding groove part 52 arrange|positioned at the both sides of the circumferential direction of the magnet 48 arrange|positioned every other in the circumferential direction. The winding slots 52 are arranged one at a time between the plurality of magnets 48 . One winding slot portion 52 is formed in each first stator core 50A and each second stator core 50B. The winding groove portion 52 is formed to be recessed from the radially outer side that is the side facing the rotor 40 to the radially inner side on the opposite side.

Each stator core 50A, 50B has, in addition to the winding groove 52 , an arc-shaped magnetic circuit connecting portion 54 adjacent to the winding groove 52 on the bottom side, and arc-shaped magnetic circuit connecting portions 54 adjacent to the winding groove 52 on both sides in the circumferential direction. Magnetic circuit parts 56A, 56B. The magnetic circuit connecting portion 54 connects the respective magnetic circuit portions 56A, 56B in the circumferential direction. The magnetic circuit portions 56A, 56B extend radially outward on the side facing the rotor 40 . The magnetic circuit portions 56A, 56B include a first magnetic circuit portion 56A adjacent to the winding slot portion 52 in one circumferential direction (clockwise in the figure), and a first magnetic circuit portion adjacent to the other circumferential direction (counterclockwise in the figure). The second magnetic circuit part 56B.

FIG. 4 is a cross-sectional view showing the armature winding 60 of the generator 10 . In this figure, the winding direction B of the armature winding 60 on one side in the axial direction of the rotor 40 (the front side in the drawing) is also shown. The stator 38 also has an armature winding 60 wound between the winding grooves 52 adjacent to each magnet 48 on both sides in the circumferential direction so as to straddle each of the magnets 48 in the circumferential direction. The armature windings 60 are provided corresponding to each of the plurality of magnets 48 , and the number of the armature windings 60 is the same as that of the magnets 48 . The armature winding 60 is wound so as to surround the corresponding magnet 48 from both sides in the circumferential direction and both sides in the axial direction.

The armature winding 60 is wound as a concentrated winding between adjacent winding slots 52 in the circumferential direction, but may be wound as a distributed winding via another winding slot 52 . Armature windings 60 adjacent in the circumferential direction are wound in winding directions B opposite to each other, but may also be wound in the same direction.

As will be described later, in the armature winding 60 , when the rotor 40 rotates, an alternating current of the same phase is generated. The armature windings 60 are electrically connected in parallel, their output terminals are connected to a rectifier circuit not shown, and single-phase AC power is output to the rectifier circuit. The rectified short-circuit rectifies and smooths the alternating current, converts it into direct current, and supplies it to the headlight 24 (see FIG. 1 ) which is an external electric device. In addition, each armature winding 60 may be electrically connected in series.

Here, as shown in FIG. 3 , the stator 38 has: a first stator salient pole portion 62A provided in each of the plurality of first magnetic circuit portions 56A to be opposed to the rotor 40 ; and a second stator salient pole portion 62B. Each of the plurality of second magnetic circuit portions 56B is provided to face the rotor 40 . The stator salient pole portions 62A, 62B protrude from the magnetic circuit portions 56A, 56B toward the radially outer side that is the side facing the rotor 40 . Each first magnetic circuit portion 56A is provided with two first stator salient pole portions 62A, and each second magnetic circuit portion 56B is provided with two second stator salient pole portions 62B. A total of 16 stator salient pole portions 62A, 62B are provided in this example.

The stator salient pole portions 62A, 62B are arranged with a predetermined gap in the radial direction with respect to the rotor salient pole portion 44 . The respective stator salient pole portions 62A, 62B are configured to have the same width as the width w of the rotor salient pole portion 44 .

FIG. 5 is a diagram showing the positional relationship between the rotor salient pole portion 44 and the stator salient pole portions 62A, 62B. In this figure, in order to distinguish some of the plurality of salient pole portions, letters such as (a) are attached at the end of each symbol to indicate. The same is also shown in the following drawings.

The plurality of first stator salient pole portions 62A provided in one first magnetic circuit portion 56A are arranged at positions shifted in the circumferential direction by an angle equal to the salient pole pitch λ of each rotor salient pole portion 44 . The plurality of second stator salient pole portions 62B provided in one second magnetic circuit portion 56B are also arranged at positions shifted in the circumferential direction by an angle equal to the salient pole pitch λ. Further, the other second stator salient pole portions 62B adjacent to the first stator salient pole portion 62A in the circumferential direction are arranged at positions shifted in the circumferential direction by an angle equal to λ×1.5.

Thus, when n is a natural number equal to or greater than 1, the first stator salient pole portion 62A is arranged at a position shifted in the circumferential direction by an angle equal to λ×n from the other first stator salient pole portions 62A. For example, the first stator salient pole portion 62A(d) is staggered by λ×4 (=λ×1.5+λ+λ×1.5 ), staggered by λ×1.0 with respect to other first stator salient pole portions 62A(c) adjacent in the counterclockwise direction. The second stator salient pole portion 62B is similarly arranged at a position shifted in the circumferential direction by an angle equal to λ×n with respect to the other second stator salient pole portions 62B.

Furthermore, the second stator salient pole portion 62B is disposed at a position shifted in the circumferential direction by an angle equal to λ×(n+0.5) with respect to the first stator salient pole portion 62A. For example, the second stator salient pole portion 62B(e) is staggered by λ×2.5 (=λ+λ×1.5) relative to the first stator salient pole portion 62A(g) adjacent in the clockwise direction, The first stator salient pole portions 62A(d) adjacent to each other in the counterclockwise direction are shifted by λ×1.5.

The operation of the generator 10 described above will be described using FIGS. 6 to 9 . Each figure shows the state when the rotor 40 rotates in the direction P by an electrical angle of π/2. In addition, in FIGS. 6 and 8 , the flow of the main magnetic flux among the magnetic fluxes flowing through the rotor core 46 and the like is mainly shown, and the flow of the leakage magnetic flux is omitted. Moreover, the flow of the leakage magnetic flux is shown in FIG. 7 and FIG. 9 . The electrical angle in the positional relationship shown in FIG. 6 is zero, and the electrical angles are π/2, π, and 3π/2 in FIGS. 7 to 9 . In addition, for convenience, one rotor salient pole portion 44 ( a ) is shown with an “o” mark.

As shown in FIG. 6 , when the electrical angle is zero, the first stator salient pole portion 62A overlaps the entire circumferential width of the adjacent rotor salient pole portion 44 when viewed in the radial direction of the rotor 40 . In addition, when viewed in the radial direction of the rotor 40 , the second stator salient pole portion 62B is at a position that does not overlap with the adjacent rotor salient pole portion 44 over the entire width in the circumferential direction, that is, at a position that is shifted in the circumferential direction. In other words, the range in which the first stator salient pole portion 62A overlaps with one of the nearby rotor salient pole portions 44 in the circumferential direction (hereinafter referred to as the first overlapping range) is more convex than the second stator salient pole portion 62B with respect to the other nearby rotor salient pole portion 44 . The range in which the pole portions 44 overlap in the circumferential direction (hereinafter referred to as the second overlapping range) is large. As a result, the magnetic resistance between the second stator salient pole portion 62B and the rotor salient pole portion 44 is compared with the first magnetic resistance R1 that is the magnetic resistance between the first stator salient pole portion 62A and the rotor salient pole portion 44 . That is, the second magnetic resistance R2 is greatly increased.

As a result, by the magnetic flux generated from one magnet 48, the first stator salient pole portion 62A passing through the first stator core 50A adjacent to one magnetic pole surface of the magnet 48, and the first stator salient pole portion 62A connected to the other magnetic pole surface are formed. Closed-loop magnetic circuit Mp of the first stator salient pole portion 62A of the adjacent second stator core 50B. For example, the upper magnet 48 (b) in the figure forms a magnetic circuit Mp via the magnetic circuit connection portion 54 of the first stator core 50A (b) → the first magnetic circuit Mp of the first stator core 50A (b). Road portion 56A → first stator salient pole portion 62A (g) → rotor salient pole portion 44 (g) → annular base portion 42 of rotor 40 → rotor salient pole portion 44 (c), (d) → first stator Salient pole part 62A(c), 62A(d)→1st magnetic circuit part 56A of 2nd stator core 50B(a) returns to the first magnet 48(b).

This magnetic circuit Mp is formed so as to interlink in the radial direction in each armature winding 60 . At this time, since the circumferentially facing magnetic poles of the plurality of magnets 48 have the same polarity, the rotational directions of the magnetic circuits Mp generated by the circumferentially adjacent magnets 48 are opposite to each other. For example, the magnetic circuit Mp generated by the magnet 48 ( b ) on the upper side in the figure is counterclockwise, and the magnetic circuit Mp generated by the magnet 48 ( b ) on the left side in the figure is clockwise. As a result, the magnetic fluxes generated from the respective magnets 48 are interlinked in the same direction within one armature winding 60 . For example, in the armature winding 60 (b) on the upper side in the figure, the magnetic flux generated by the magnet 48 (b) on the upper side in the figure and the magnetic flux generated by the magnet 48 (a) on the left side in the figure are equal to each other. Cross-chain in the same direction.

As shown in FIG. 7 , when the electrical angle is π/2, when viewed in the radial direction of the rotor 40 , the first stator salient pole portion 62A is at a position overlapping with the adjacent rotor salient pole portion 44 over approximately half the width of the circumferential direction. . In addition, the same applies to the second stator salient pole portion 62B. In other words, the first overlapping range in which the first stator salient pole portion 62A overlaps with the rotor salient pole portion 44 is the same as the second overlapping range in which the second stator salient pole portion 62B overlaps with the rotor salient pole portion 44 . Accordingly, the first magnetic resistance R1 and the second magnetic resistance R2 have the same magnitude.

As a result, by the magnetic flux generated from one magnet 48, the second stator salient pole portion 62B passing through the first stator core 50A adjacent to one magnetic pole surface of the magnet 48, and the second stator salient pole portion 62B adjacent to the other magnetic pole surface are formed. The closed-loop magnetic circuit Mp of the first stator salient pole portion 62A of the adjacent second stator core 50B. For example, the magnet 48 (b) on the upper side in the figure forms a magnetic circuit Mp as follows: via the second magnetic circuit portion 56B of the first stator core 50A (b) → the second stator salient pole portion 62B (e), (f ) → rotor salient pole portions 44 ( e ), 44 ( f ) → annular base portion 42 of rotor 40 → rotor salient pole portions 44 ( c ), 44 ( d ) → first stator salient pole portions 62A ( c ), (d)→The first magnetic circuit portion 56A of the second stator core 50B(a) returns to the first magnet 48(b). The magnetic circuit Mp reciprocates in the radial direction within each armature winding 60 , and is formed so as not to interlink within each armature winding 60 .

As shown in FIG. 8 , when the electrical angle is π, viewed from the radial direction of the rotor 40, the first stator salient pole portion 62A is in such a position that it does not overlap with the adjacent rotor salient pole portion 44 throughout the entire width of the circumferential direction. position, that is to say in a position that is staggered in the circumferential direction. Further, when viewed in the radial direction of the rotor 40 , the second stator salient pole portion 62B is at a position overlapping the entire circumferential width of the rotor salient pole portion 44 in the vicinity thereof. In other words, the second overlapping range in which the second stator salient pole portion 62B overlaps with the rotor salient pole portion 44 is larger than the first overlapping range in which the first stator salient pole portion 62A overlaps with the rotor salient pole portion 44 . Thus, the first magnetic resistance R1 is significantly larger than the second magnetic resistance R2.

As a result, by the magnetic flux generated from one magnet 48, the second stator salient pole portion 62B passing through the first stator core 50A adjacent to one magnetic pole surface of the magnet 48 and the second stator salient pole portion 62B connected to the other magnetic pole surface are formed. Closed-loop magnetic circuit Mp of the second stator salient pole portion 62B of the adjacent second stator core 50B. For example, the magnet 48 (b) on the upper side in the figure forms a magnetic circuit Mp as follows: via the second magnetic circuit portion 56B of the first stator core 50A (b) → the second stator salient pole portion 62B (e), (f ) → rotor salient pole portions 44 ( e ), 44 ( f ) → annular base portion 42 of rotor 40 → rotor salient pole portions 44 ( a ), 44 ( t ) → second stator salient pole portions 62B ( a ), 62B (b)→The magnetic circuit connecting portion 54 of the second stator core 50B(a) returns to the first magnet 48(b).

The magnetic circuit Mp is formed so as to interlink in the radial direction in each armature winding 60 . At this time, in the magnetic circuit Mp, the direction of interlinkage in the armature winding 60 is the direction opposite to the radial direction compared to when the electrical angle is zero (see FIG. 6 ).

As shown in FIG. 9 , when the electrical angle is 3π/2, viewed from the radial direction of the rotor 40, the first stator salient pole portion 62A is at a position overlapping with the adjacent rotor salient pole portion 44 over half the circumferential width. . Further, when viewed in the radial direction of the rotor 40 , the second stator salient pole portion 62B is positioned to overlap the adjacent rotor salient pole portion 44 over a half width in the circumferential direction. Accordingly, the first magnetic resistance R1 and the second magnetic resistance R2 have the same magnitude. As a result, the same magnetic circuit Mp as when the electrical angle is π/2 is formed.

As mentioned above, in the state where the electrical angle is zero (hereinafter referred to as the first state), the second reluctance R2 is significantly larger than the first reluctance R1, and in the state where the electrical angle is 3π/2 (hereinafter referred to as the second state), the first reluctance R1 is significantly larger than the second reluctance R2. These first and second states are alternately switched as the rotor 40 rotates.

As shown in FIGS. 6 and 8 , in one armature winding 60 (for example, the armature winding 60 (b)), in the first state, a magnetic circuit Mp interlinked in one direction in the radial direction is formed, and in the second state In the state, a magnetic circuit Mp interlinked in the other direction of the radial direction is formed. That is, when switching between the first state and the second state, switching is performed in such a manner that the magnetic flux interlinked in each armature winding 60 reverses in the radial direction, and a magnetic flux generated in each armature winding 60 AC induced electromotive force. At this time, an alternating current of the same phase is generated in each armature winding 60 . In this way, in the generator 10 , the positions of the plurality of rotor salient pole portions 44 and the plurality of stator salient pole portions 62A, 62B are determined such that the first state and the second state are alternately switched.

The operation and effect of the generator 10 described above will be described.

In general, the frequency f (Hz) of the generator satisfies the relationship of the following mathematical expression (1) between the rotational speed N (r/min) of the rotor and the number of poles P of the generator.

N=120×f/P…(1)

In the generator 10 of the present embodiment, the present inventors have found that twice the number of rotor salient pole portions 44 is the number P of poles of the generator. This knowledge was obtained through analysis using the structure shown in FIG. 3 . In this analysis, the rotational speed N of the rotor 40 was set to 120 (r/min), and the frequency f (Hz) of the electric power generated by each armature winding 60 was obtained. As a result, the frequency f was found to be 40 (Hz), and it was confirmed that twice the number (20) of rotor salient pole portions 44 is the number P of poles of the generator from the formula (1).

Therefore, in the generator 10 of the present embodiment, if the rotor salient pole portions 44 and the stator salient pole portions 62A, 62B are arranged at predetermined positions, the greater the number of the rotor salient pole portions 44, the greater the frequency of the induced electromotive force. Even when the rotational speed of the rotor 40 is low, it is easy to obtain high-frequency alternating current. In addition, since the voltage of the induced electromotive force is proportional to the product of the magnetic flux interlinked in the armature winding 60 and the frequency, the alternating current capable of obtaining a high frequency becomes the alternating current capable of obtaining a high voltage accordingly.

In addition, the first stator salient pole portion 62A and the second stator salient pole portion 62B are provided at positions sandwiching the magnet 48 and the winding groove portion 52 , so that the intervals between them can be easily separated. Thus, even if the first stator salient pole portion 62A and the second stator salient pole portion 62B are excited to have different polarities by the magnet 48 , it is possible to easily suppress the polarity between the first stator salient pole portion 62A and the second stator salient pole portion 62A. Generation of leakage magnetic flux between parts 62B. Therefore, it is easy to reduce the outer diameter dimensions of the rotor 40 and the stator 38 of the generator 10 while suppressing the generation of leakage magnetic flux between the first stator salient pole portion 62A and the second stator salient pole portion 62B. In addition, such suppression of the generation of leakage magnetic flux between the first stator salient pole portion 62A and the second stator salient pole portion 62B is to suppress the reduction of the interlinked magnetic flux in the armature winding 60, and it is easy to use the generator 10 to obtain sufficient output voltage.

In addition, for example, in the three-phase alternator described in Japanese Patent Application Laid-Open No. 2012-182961, in which the armature winding is wound on each of the plurality of salient pole portions of the stator, as the number of magnetic poles of the rotor increases, The number of armature windings increases, correspondingly resulting in high cost and reduced assembly. In this regard, in this embodiment, high-frequency alternating current can be obtained, and only the number of rotor salient pole portions 44 can be increased without increasing the number of magnets 48 and armature windings 60, so that the number of components can be reduced accordingly. , it is possible to reduce the cost while obtaining good assemblability.

Furthermore, in the conventional claw pole generator, the magnetic flux flowing from the magnets of the rotor to the claws of each stator core changes direction in the axial direction within the claws and then flows toward the bases of the claws. The magnetic circuit cross-sectional area of the claw portion perpendicular to the magnetic circuit direction (axial direction) is determined according to the radial thickness and peripheral length of the claw portion. Here, in the case of reducing the outer diameter dimension without changing the axial length of the generator, the axial length of the claw portion of the stator core does not change but becomes thinner in the circumferential direction, and the gap surface facing the magnet becomes thinner, and The thickness in the radial direction is reduced, and as a result, the cross-sectional area of the magnetic circuit at the base of the claw portion is reduced. Accordingly, the magnetic flux received by the claw portion of the stator core on the gap surface tends to concentrate on the root portion of the claw portion having a small magnetic circuit cross-sectional area, and magnetic saturation tends to occur at the root portion. As a result, it is difficult for the magnetic flux interlinked in the armature winding to flow, and it is difficult to obtain a sufficient output voltage by the generator.

In this regard, in the generator 10 of the present embodiment, the magnetic flux flows not in the axial direction but in the radial direction in the stator salient pole portions 62A, 62B of the stator core 50 . The magnetic circuit cross-sectional area of the stator salient pole portions 62A, 62B perpendicular to the magnetic circuit direction (radial direction) is determined according to the axial length and the peripheral length of the stator salient pole portions 62A, 62B, even if the outer diameter of the generator 10 is reduced in size The situation is not easy to change. Therefore, even when the outer diameter of the generator 10 is reduced in size, the magnetic path cross-sectional area of the stator salient pole portions 62A, 62B can be ensured by increasing the axial length of the stator core 50 . Accordingly, even when the outer diameter of the generator 10 is reduced in size, it is possible to suppress the occurrence of magnetic saturation of the salient pole portions 62A, 62B of the stator, and suppress a decrease in the magnetic flux interlinked in the armature winding 60, thereby It is easy to obtain a sufficient output voltage with the generator 10 .

And, every time switching between the first state and the second state, the direction of the magnetic circuit Mp generated by the one magnet 48 in the armature winding 60 can be reversed, which can be compared with not reversing the direction. By increasing the amount of change in the magnetic flux interlinked in the armature winding 60, it becomes easier to obtain high-voltage alternating current. And, every time switching between the first state and the second state, one magnet 48 can be used to reverse the direction of the magnetic circuit Mp generated in one armature winding 60. Therefore, while suppressing the number of magnets 48, At the same time, it is easy to obtain high-voltage alternating current.

In addition, each first stator salient pole portion 62A is offset from the other first stator salient pole portion 62A by an angle equal to λ×n, and each second stator salient pole portion 62B is offset from the first stator salient pole portion 62A. Stagger at an angle equal to λ×(n+0.5). As a result, the relative positions of the stator salient pole portions 62A, 62B with respect to the rotor salient pole portion 44 are aligned, and the change mode of the magnetic circuit Mp formed by the magnetic flux generated from each magnet 48 is made to be the same. Alternating current of the same phase can be easily obtained.

Furthermore, since the stator cores 50A, 50B and the rotor core 46 can be formed by laminating a plurality of metal plates, iron loss due to eddy currents in the portions through which the main magnetic flux passes can be significantly suppressed.

[Second Embodiment]

FIG. 10 is a cross-sectional view showing a generator 10 according to the second embodiment, and FIG. 11 is a cross-sectional view showing an armature winding 60 of the generator 10 . A total of 20 rotor salient pole portions 44 of the rotor 40 are provided in the example of FIG. 3 , but a total of 18 are provided in this example. The salient pole pitch λ is 20° (=360°/18).

A total of four magnets 48 and stator cores 50A and 50B of the stator 38 are respectively provided in the example of FIG. 3 , but a total of two are provided in this example. In addition, although two first stator cores 50A and two second stator cores 50B are provided in the example of FIG. 3 , one is provided in this example. In addition, in the example of FIG. 3 , two first stator salient pole portions 62A and two second stator salient pole portions 62B are provided in each of the first magnetic circuit portion 56A and the second magnetic circuit portion 56B, but in this example Set 4 each. Thus, the numbers of the rotor salient pole portions 44 and the stator salient pole portions 62A and 62B are not particularly limited.

The operation of the generator 10 described above will be described using FIGS. 12 to 15 . Each figure shows the state when the rotor 40 rotates in the direction P by an electrical angle of π/2. 12 and 14 mainly show the flow of the main magnetic flux among the magnetic fluxes flowing through the rotor core 46 and the like, and the flow of the leakage magnetic flux is omitted. Moreover, the flow of the leakage magnetic flux is shown in FIG. 13 and FIG. 15 . The electrical angle in the positional relationship shown in FIG. 12 is zero, and the electrical angles are π/2, π, and 3π/2 in FIGS. 13 to 15 .

As shown in FIG. 12 , when the electrical angle is zero, the first stator salient pole portion 62A overlaps the entire circumferential width of the adjacent rotor salient pole portion 44 as viewed from the radial direction of the rotor 40 . Viewed in the radial direction of the rotor 40 , the second stator salient pole portion 62B is at a position that does not overlap with the adjacent rotor salient pole portion 44 over the entire width in the circumferential direction, that is, at a position that is shifted in the circumferential direction. In other words, the first overlapping range in which the first stator salient pole portion 62A overlaps with the rotor salient pole portion 44 is larger than the second overlapping range in which the second stator salient pole portion 62B overlaps with the rotor salient pole portion 44 . Thereby, similarly to the first embodiment, a closed-loop magnetic circuit Mp is formed so as to interlink in the radial direction in each armature winding 60 .

As shown in FIG. 13 , when the electrical angle is π/2, viewed from the radial direction of the rotor 40 , the first stator salient pole portion 62A is at a position overlapping with the adjacent rotor salient pole portion 44 over half the circumferential width. . Further, when viewed in the radial direction of the rotor 40 , the second stator salient pole portion 62B is positioned to overlap the adjacent rotor salient pole portion 44 over a half width in the circumferential direction. In other words, the first overlapping range in which the first stator salient pole portion 62A overlaps with the rotor salient pole portion 44 is the same as the second overlapping range in which the second stator salient pole portion 62B overlaps with the rotor salient pole portion 44 . Thereby, similarly to the first embodiment, a closed-loop magnetic circuit Mp is formed to reciprocate in the radial direction in each armature winding 60 .

As shown in FIG. 14 , when the electrical angle is π, viewed from the radial direction of the rotor 40, the first stator salient pole portion 62A does not overlap with the adjacent rotor salient pole portion 44 over the entire width of the circumferential direction. position, that is to say in a position that is staggered in the circumferential direction. Viewed in the radial direction of the rotor 40 , the second stator salient pole portion 62B is at a position overlapping the entire width of the adjacent rotor salient pole portion 44 over the entire width of the circumferential direction. In other words, the second overlapping range in which the second stator salient pole portion 62B overlaps with the rotor salient pole portion 44 is larger than the first overlapping range in which the first stator salient pole portion 62A overlaps with the rotor salient pole portion 44 . Thereby, similarly to the first embodiment, a closed-loop magnetic circuit Mp is formed so as to interlink in the radial direction in each armature winding 60 .

As shown in FIG. 15 , when the electrical angle is 3π/2, when viewed in the radial direction of the rotor 40 , the first stator salient pole portion 62A is at a position overlapping the half width of the adjacent rotor salient pole portion 44 over the circumferential direction. . Further, when viewed in the radial direction of the rotor 40 , the second stator salient pole portion 62B is positioned to overlap the adjacent rotor salient pole portion 44 over a half width in the circumferential direction. This forms the same magnetic circuit Mp as when the electrical angle is π/2.

The inventors of the present invention also found that twice the number of rotor salient pole portions 44 is the number P of poles of the generator in the above generator 10 . This knowledge was obtained through analysis performed using the structure shown in FIG. 10 . In this analysis, the rotational speed N of the rotor 40 was set to 120 (r/min), and the frequency f (Hz) of the electric power generated by each armature winding 60 was obtained. As a result, the frequency f was found to be 36 (Hz), and it was confirmed that twice the number (18) of rotor salient pole portions 44 is the number P of poles of the generator from the mathematical expression (1).

Therefore, with the generator 10 of the present embodiment, as in the first embodiment, the larger the number of salient pole portions 44 of the rotor, the higher the frequency of the induced electromotive force, and even when the rotational speed of the rotor 40 is small, it is easy to obtain high frequency alternating current. In other respects, the same effects as those of the first embodiment are obtained.

As mentioned above, although this invention was demonstrated based on embodiment, this embodiment merely shows the principle and application of this invention. In addition, in the embodiment, a large number of modifications and configuration changes can be made without departing from the scope of the present invention defined by the claims.

The generator 10 has been described taking a bicycle generator as an example, but its application is not limited thereto. Furthermore, when the generator 10 is a generator for bicycles, the rotor 40 only needs to be able to rotate in conjunction with the rotation of the rotating part of the bicycle 12 . Here, the rotating part has been described taking the front wheel 22 as an example of a wheel, but it may be a pulley of a rear derailleur (chain tensioner) or the like in addition to a hub shell and a crank. In addition, the generator 10 may be configured as a roller generator or the like instead of a hub generator. Although the generator 10 has been exemplified as an outer-rotor generator, it may be an inner-rotor generator in which the rotor 40 is disposed on the inner peripheral side of the stator 38 .

Although the example in which the first stator core 50A and the second stator core 50B of the stator 38 are configured separately has been described, the first stator core 50A and the second stator core 50B may also be configured integrally. Furthermore, an example in which the width of the stator salient pole portions 62A and 62B is equal to the width w of the rotor salient pole portion 44 has been described, but the width w of the rotor salient pole portion 44 may be equal to or less, or the rotor salient pole portion 44 may be of width w or more.

The positions of the rotor salient pole portion 44 and the stator salient pole portion 62A, 62B are not limited to the illustrated example, as long as the first state in which the second reluctance is greater than the first reluctance is determined and the first reluctance is greater than the second reluctance The second state of can be alternately switched.

On the basis of satisfying this condition, in the first state, the first overlapping range where the first stator salient pole portion 62A overlaps with the rotor salient pole portion 44 may be larger than that of the second stator salient pole portion 62B and the rotor salient pole portion. The second coincidence range of 44 coincidence is large. In addition, the second overlapping range may be made larger than the first overlapping range in the second state while satisfying this condition.

For example, in FIGS. 6 and 12 , an example in which the first overlapping range is a range over the entire width in the circumferential direction of the first stator salient pole portion 62A and there is no second overlapping range when in the first state has been described. In addition, in the first state, for example, the first overlapping range may be the same range as the illustrated example, and the second overlapping range may be relative to the rotor salient pole portion 44 in the vicinity of the second stator salient pole portion 62B. The range over the half width or less of the second stator salient pole portion 62B overlaps. At this time, the second stator salient pole portion 62B is at a circumferentially shifted position relative to the one rotor salient pole portion 44 such that the second overlapping range is smaller than the first overlapping range.

Also in FIGS. 8 and 14 , an example in which there is no first coincidence range and the second coincidence range is a range over the entire width of the second stator salient pole portion 62B in the circumferential direction when in the second state is explained. In addition, in the second state, for example, the second overlapping range may be the same range as the illustrated example, and the first overlapping range may be relative to the rotor salient pole near the first stator salient pole portion 62A. The portion 44 overlaps over a range that is less than half the width of the first stator salient pole portion 62A.

Claims (7)

1. an electromotor, it is characterised in that including:

Rotor；With

Stator, has: multiple Magnet, and the plurality of Magnet configures the most at spaced intervals, and the most opposed magnetic pole is homopolarity；Stator core, this stator core includes the slot for winding portion being arranged in the circumferential both sides of above-mentioned Magnet；And armature winding, this armature winding is wound between above-mentioned slot for winding portion in the way of circumferentially crossing over above-mentioned Magnet,

Above-mentioned rotor has rotor core, and this rotor core is included in the circumferentially spaced multiple rotor with salient pole portions alternately formed,

Said stator iron core has: the first stator salient poles portion, is being opposed to arrange with above-mentioned rotor in the magnetic circuit part that a side of circumference is adjacent relative to above-mentioned slot for winding portion；With the second stator salient poles portion, it is being opposed to arrange with above-mentioned rotor in the magnetic circuit part that the opposing party of circumference is adjacent relative to above-mentioned slot for winding portion.

Electromotor the most according to claim 1, it is characterised in that

In the case of the magnetic resistance between above-mentioned first stator salient poles portion and above-mentioned rotor with salient pole portion being set to the first magnetic resistance and the magnetic resistance between above-mentioned second stator salient poles portion and above-mentioned rotor with salient pole portion is set to the second magnetic resistance, the position in above-mentioned multiple rotor with salient pole portion, above-mentioned first stator salient poles portion and above-mentioned second stator salient poles portion is defined as, when above-mentioned rotor rotates, above-mentioned second magnetic resistance alternately switches more than the second state of above-mentioned second magnetic resistance with above-mentioned first magnetic resistance more than the first state of above-mentioned first magnetic resistance.

Electromotor the most according to claim 1 and 2, it is characterised in that

When setting following state as the first state: about the center of rotation of above-mentioned rotor, bigger relative to the scope that neighbouring above-mentioned rotor with salient pole portion overlaps in the circumferential than observing above-mentioned second stator salient poles portion from above-mentioned radial direction relative to the scope that neighbouring above-mentioned rotor with salient pole portion overlaps in the circumferential from radially observing above-mentioned first stator salient poles portion

And when setting following state as the second state: observe above-mentioned second stator salient poles portion from above-mentioned radial direction bigger relative to the scope that neighbouring above-mentioned rotor with salient pole portion overlaps in the circumferential than observing above-mentioned first stator salient poles portion from above-mentioned radial direction relative to the scope that neighbouring above-mentioned rotor with salient pole portion overlaps in the circumferential

The position in above-mentioned multiple rotor with salient pole portion, above-mentioned first stator salient poles portion and above-mentioned second stator salient poles portion is defined as, and above-mentioned first state alternately switches with above-mentioned second state.

4. according to the electromotor described in any one in claims 1 to 3, it is characterised in that

Above-mentioned multiple rotor with salient pole portion is arranged in the position staggered in the circumferential with the angle equal with predetermined angular λ,

Above-mentioned first stator salient poles portion is arranged in relative to other the first stator salient poles portion with the natural number with λ × n(n being more than 1) position staggered in the circumferential of equal angle,

Above-mentioned second stator salient poles portion is arranged in relative to above-mentioned first stator salient poles portion with the position staggered in the circumferential with the angle that λ × (n+0.5) is equal.

5. according to the electromotor described in any one in Claims 1-4, it is characterised in that

Above-mentioned rotor core and said stator iron core are consisted of the multiple metallic plate of stacking on the axis direction of the center of rotation of above-mentioned rotor.

6. according to the electromotor described in any one in claim 1 to 5, it is characterised in that

This electromotor is the generator of bicycle that above-mentioned rotor can rotate in linkage with the rotation of the rotating part of bicycle.

Electromotor the most according to claim 6, it is characterised in that

This electromotor is the hub generator of bicycle.