JP2012182961A - Hub dynamo for bicycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hub dynamo which easily takes out the output current while generating a three phase alternating current.SOLUTION: A hub dynamo 10 includes: a stator unit 20 fixed to a hub shaft 11; and a rotor unit 30 fixed to a dynamo case 12. The stator unit 20 is used for generating a three phase alternating current. A circuit board 40 including a rectification circuit 42, which converts a three phase alternating current output of the stator unit 20 into a direct current output, is disposed in the dynamo case 12. The circuit board 40 is supported on the hub shaft 11 by a holder 41 made of a conductive material. The holder 41 electrically connects one of a pair of output lines 42a taking out the direct current output with the hub shaft 11.

Description

  The present invention relates to a bicycle hub dynamo.

  Many bicycles used daily are equipped with a dynamo to supply power consumed by headlamps. In recent years, a hub dynamo incorporated into a wheel hub has become common.

  A normal hub dynamo generates electricity with a single-phase alternating current. In order to improve power generation efficiency, power generation with three-phase alternating current also exists as a technical option. Examples of a hub dynamo that generates power with three-phase alternating current are described in Patent Documents 1 and 2.

JP-A-2004-112965 (International Patent Classification: H02K21 / 22, B62J6 / 12, H02K5 / 22, H02K7 / 116, H02K7 / 18) Japanese Patent Application Laid-Open No. 2004-15909 (International Patent Classification: H02K21 / 22, B60Q1 / 02, B62J6 / 02, B62J6 / 12, H02K7 / 10)

  In the case of three-phase alternating current, there are three output lines, and it is difficult to derive all of them from the hub dynamo both in terms of design and assembly.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a hub dynamo capable of easily taking out an output current while performing three-phase AC power generation.

  According to a preferred embodiment of the present invention, a bicycle hub dynamo having a hub shaft and a dynamo case rotatably held on the hub shaft is fixed to the stator unit fixed to the hub shaft and the dynamo case. The stator unit is for three-phase AC power generation, and a circuit board including a rectifier circuit that converts the three-phase AC output of the stator unit into a DC output is disposed in the dynamo case.

  According to a preferred embodiment of the present invention, in the bicycle hub dynamo having the above-described configuration, the circuit board is supported on the hub shaft by a holder made of a conductive material, and the holder has a pair of output lines for taking out the DC output. It plays a role of electrically connecting one to the hub shaft.

  According to a preferred embodiment of the present invention, in the bicycle hub dynamo configured as described above, the iron core included in the stator unit is a laminated iron core.

  According to a preferred embodiment of the present invention, in the bicycle hub dynamo having the above-described configuration, the number of poles of the iron core and the number of magnets included in the rotor unit are different.

  According to the present invention, since the three-phase alternating current is converted into the direct current in the dynamo case and then output, the number of output lines can be reduced and the use of the three-phase alternating current becomes easy.

It is a partial side view of a bicycle provided with a hub dynamo according to an embodiment of the present invention. It is front sectional drawing of the hub dynamo which concerns on embodiment of this invention. It is a front view of the stator unit contained in the hub dynamo concerning the embodiment of the present invention. It is the side view which looked at the stator unit contained in the hub dynamo which concerns on embodiment of this invention in the arrow A direction of FIG. It is the side view which looked at the stator unit and circuit board contained in the hub dynamo which concern on embodiment of this invention in the arrow B direction of FIG. It is a figure which shows the combination of the stator unit and rotor unit in the hub dynamo which concerns on embodiment of this invention. It is the side view which looked at the combination of the stator unit and rotor unit in the hub dynamo which concerns on embodiment of this invention in the arrow C direction of FIG. It is a circuit diagram of a rectifier circuit. It is a side view of a headlamp. FIG. 10 is a horizontal sectional view of the headlamp of FIG. 9. FIG. 10 is a partial front view of the headlamp of FIG. 9. FIG. 10 is a lighting circuit diagram of the headlamp of FIG. 9. It is a side view of the conventional headlamp. FIG. 14 is a horizontal sectional view of the headlamp of FIG. 13.

  FIG. 1 illustrates a situation in which a hub dynamo 10 is provided on the front wheel 2 of the bicycle 1. The hub dynamo 10 is supported by a front fork 4 connected to the handle 3, and is supported by the rim 2 a of the front wheel 2 by a plurality of spokes 5. A headlamp 6 that receives power supply from the hub dynamo 10 is attached to the front fork 4.

  As shown in FIG. 2, the hub dynamo 10 has a hub shaft 11 and a dynamo case 12. The hub shaft 11 is fixed so that it does not fall off from the front fork 4 and does not rotate with respect to the front fork 4 by tightening the front fork 4 with the nuts 14 screwed into the male screw portions 13 at both ends via the washer 70. Is done.

  The dynamo case 12 is a substantially cylindrical hollow part, and one end is an opening. A disk-shaped lid 15 is fitted into the opening and is fixed to form an internal space 16 isolated from the outside. The dynamo case 12 is rotatable about the hub shaft 11 by a ball bearing 17 interposed between the end on the non-opening side and the hub shaft 11 and a ball bearing 18 interposed between the lid 15 and the hub shaft 11. Retained. Between the ball bearings 17 and 18 and the hub shaft 11, sleeves 71 and 72 fixed to the hub shaft 11 are interposed. A cover 73 covers the sleeve 71.

  The dynamo case 12 has an outer flange 19 in the vicinity of the left and right ends. A plurality of spoke attachment holes 19a are formed in the outer flange 19 at a predetermined angular interval, and the root portions of the spokes 5 are attached to the spoke attachment holes 19a.

  A stator unit 20 and a rotor unit 30 are accommodated in the internal space 16 of the dynamo case 12. Hereinafter, the structure of the stator unit 20 and the rotor unit 30 will be described with reference to FIGS. 3 to 8.

  The stator unit 20 includes an iron core 21 made of a laminated iron core. As shown in FIG. 4, a total of nine pole pieces 21 a are formed on the iron core 21. A coil 22 is wound around the pole piece 21a. The coil 22 is a three-phase star connection as shown in FIG.

  The iron core 21 has a through hole in the center, and the hub shaft 11 is passed through the through hole. The stator unit 20 is not displaced in the axial direction of the hub shaft 11 by the nut 23 screwed into the hub shaft 11 via the washer 74 and the spring washer 75 in the inner space 16 of the dynamo case 12, and is attached to the hub shaft 11. It is fixed so as not to rotate.

  Arranged inside the dynamo case 12 is a circuit board 40 provided with a rectifier circuit that rectifies the three-phase alternating current generated in the coil 22 into direct current. The circuit board 40 has a donut shape and is arranged so as to align with the stator unit 20 in the axial direction of the hub shaft 11. The circuit board 40 is attached to the hub shaft 11 by a disk-shaped holder 41. The holder 41 is made of a conductive material. The holder 41 may be formed by press molding of a metal plate. The holder 41 has a through hole through which the hub shaft 11 passes, and is fixed to the hub shaft 11 together with the stator unit 20 by tightening the nut 23.

  A rectifier circuit 42 shown in FIG. 8 is formed on the circuit board 40. The rectifier circuit 42 includes six diodes 43. Three output lines 22 a of the coil 22 are connected to the rectifier circuit 42. From the rectifier circuit 42, two output lines 42a for extracting a DC output are derived.

  One of the two output lines 42 a is electrically connected to the holder end 41 a of the holder 41. The holder 41 is in a state of being electrically connected to the hub shaft 11, and one of the output lines 42 a electrically connected to the holder 41 is electrically connected to the hub shaft 11 through the holder 41. . As a result, the entire bicycle 1 to which the hub axle 11 is fixed functions as a ground for the rectifier circuit 42.

  A lead wire 44 covered with an insulating coating is connected to the other output line 42a. The lead wire 44 is led out of the hub dynamo 10 through a passage provided in the sleeve 72 and between the hub shaft 11 and the ball bearing 18.

  In FIG. 2, an output terminal 76 is connected to the lead wire 44 and is attached to the outer periphery of the sleeve 72 by a nut 78 via a washer 77. The periphery of the output terminal 76 is covered with a cover 79.

  In FIG. 5, a thick black line 47 indicates a printed wiring printed on the circuit board 40.

  The rotor unit 30 includes a ring-shaped rotor yoke 31 made of mild steel, and a ring-shaped magnet 32 fixed to the inner surface of the rotor yoke 31 with an adhesive. As shown in FIG. 7, the magnet 32 is magnetized alternately in S and N poles. The total number of S poles and N poles is 10 poles. That is, the number of poles of the magnet 32 is one more than that of the pole piece 21 a of the iron core 21.

  The rotor yoke 31 is in close contact with the inner peripheral surface of the dynamo case 12 and is fixed to the dynamo case 12 with an adhesive.

  When the front wheel rotates, relative rotation occurs between the hub axle 11 and the dynamo case 12, and the magnetic flux formed by the magnet 32 crosses the pole pieces 21a of the iron core 21 one after another. As a result, a three-phase alternating current flows through the coil 22. The three-phase alternating current is rectified into a direct current by the rectifier circuit 42. The direct current is taken out from the output terminal 76 via the lead wire 44 and used for lighting the headlamp 6 or the like.

  Since the stator unit 20 generates a three-phase alternating current, the power generation efficiency is high. Since the iron core 21 is a laminated iron core, the power generation efficiency is further increased. The three-phase AC current is not output from the hub dynamo 10 as it is, but is converted into a DC current by the rectifier circuit 42 inside the hub dynamo 10 and output, so the number of output lines 42a can be reduced. In addition, since one of the two output wires 42a is grounded to the bicycle 1 via the holder 41, only one lead wire 44 is required to be pulled out of the hub dynamo 10 in the end. Design and assembly become easy.

  Moreover, since the number of poles of the pole piece 21a of the iron core 21 and the number of poles of the magnet 32 are made different, all the poles of the magnet 32 and all of the pole pieces 21a do not pass at the same time, and the cogging torque is reduced. To do. That is, the rotation of the hub dynamo 10 is felt smoothly, and the usability is improved. In this embodiment, the number of poles of the magnet 32 is different from the number of poles of the iron core 21 and the number of poles of the magnet 32 by increasing the number of poles of the magnet 32 by one more than the pole piece 21a of the iron core 21, but this configuration is limited. It is not something. The number of poles of the iron core 21 may be larger than the number of poles of the magnet 32, and the difference in the number of poles may be two or more.

  The headlamp 6 is devised to ensure the safety of the rider of the bicycle 1. This will be described with reference to FIGS.

  The headlamp 6 includes a bullet-type headlamp case 50 made of a synthetic resin molded product. The headlamp case 50 is attached to the front fork 4 via a metal stay 51. The head lamp case 50 has an opening on the front side, and a head cap 52 made of a transparent synthetic resin is attached thereto. The head cap 52 has an opening on the side facing the head lamp case 50, and a reflecting mirror 53 is attached thereto. The reflecting mirror 53 is a synthetic resin molded product, and a reflecting surface 53a is formed by plating or metal deposition.

  A lamp 54 is provided at the center of the reflecting mirror 53. The lamp 54 may be an incandescent light bulb or a light emitting diode (LED). A terminal portion of the lamp 54 is electrically connected to a circuit board 55 supported inside the headlamp case 50. The circuit board 55 is supplied with a direct current generated by the hub dynamo 10, and the direct current flows to the lamp 54 and the lamp 54 is lit.

  A through hole 50a is formed on the side surface facing outward in the headlamp case 50, and a box-shaped light guide lens 56 having an internal space 56a is attached thereto. The light guide lens 56 has a horizontally long front shape and a horizontal cross section having the shape shown in FIG. That is, a mountain-shaped protrusion 57 that protrudes toward the through hole 50 a is formed in the internal space 56 a of the light guide lens 56. A mountain-shaped recess 58 is formed in the center of the mountain-shaped protrusion 57 from the outer surface. The boundary surface between the thick portion of the mountain-shaped protrusion 57 and the concave portion 58 becomes the first reflection surface 57a, and the boundary surface between the thick portion of the mountain-shaped protrusion 57 and the internal space 56a of the light guide lens 56 is the second reflection surface 57b. It becomes. The second reflecting surface 57b is formed in a step shape.

  A circular through hole 50 b is formed in the headlamp case 50 at a location where it abuts on the front surface of the light guide lens 56. The reflecting mirror 53 is also formed with a circular through hole 53b at a position aligned with the through hole 50b. As a result, light from the light guide lens 56 leaks from the head cap 52 through the through holes 50b and 53b.

  The LED 59 mounted on the circuit board 55 serves as a light source that supplies light to the light guide lens 56. The LED 59 is attached so as to irradiate light to the flat portion at the apex of the mountain-shaped protrusion 57. The hub dynamo 10 supplies power to the LED 59, but after the hub dynamo 10 stops generating power, the capacitor 60 mounted on the circuit board 55 supplies power to the LED 59. As the capacitor 60, an electric double layer capacitor is selected because a certain amount of stored electricity is required.

  The electric circuit formed on the circuit board 55 includes individual circuit elements shown in FIG. That is, the rectifier circuit 61, the constant voltage circuit 62, the photo sensor circuit 63, the lighting / extinguishing control circuit 64 and the constant voltage circuit 65. The optical sensor circuit 63 includes an optical sensor 66 that detects the brightness of the outside of the headlamp 6. The on / off control circuit 64 turns on or off the lamp 54.

  When the bicycle 1 runs and the hub dynamo 10 generates power, when the light sensor 66 detects that the surroundings are darker than the predetermined brightness, such as at night, the lighting / extinguishing control circuit 64 supplies a current to the lamp 54. The lamp 54 is turned on. Thereby, light is irradiated to the front of the bicycle 1 through the head cap 52, and the passenger can drive the bicycle 1 while confirming the front by the light. In FIG. 12, a single-phase hub dynamo 10 is used, but a three-phase AC generator may be used as a matter of course.

  When the hub dynamo 10 generates power during night driving, the LED 59 is also turned on. As shown in FIG. 10, the light emitted from the LED 59 enters the thickness of the mountain-shaped protrusion 57 from the flat portion at the apex of the mountain-shaped protrusion 57, hits the first reflecting surface 57a, and is horizontal along the longitudinal axis of the headlamp 6. Reflected in the direction. The light travels through the thickness of the mountain-shaped protrusion 57 and hits the second reflecting surface 57b, and is reflected in a direction perpendicular to the longitudinal axis of the headlamp 6, that is, toward the side of the headlamp 6. Since the second reflecting surface 57b is stepped, this light shines on the viewer's eyes as a number of sparkles. For this reason, the existence of the bicycle 1 can be well recognized from the side.

  The entire amount of light emitted from the LED 59 is not reflected by the first reflecting surface 57a, but a part of the light passes through the first reflecting surface 57a. This light also helps to recognize the bicycle 1 from the side.

  The total amount of light hitting the second reflecting surface 57b is not reflected by the second reflecting surface 57b, and part of the light passes through the second reflecting surface 57b. The light passing through the front second reflection surface 57 b passes through the through hole 50 b of the headlamp case 50 and the through hole 53 b of the reflecting mirror 53 and leaks forward from the head cap 52. The presence of the bicycle 1 can be recognized from the front by this leaked light.

  The light that has passed through the rear second reflection surface 57 b leaks backward from the rear side surface of the light guide lens 56. The presence of the bicycle 1 can be recognized from behind by this leaked light.

  During the night, while the hub dynamo 10 is generating power, the capacitor 60 is charged. Even if the bicycle 1 stops and the hub dynamo 10 stops generating power, the LED 59 continues to be lit while the amount of power stored in the capacitor 60 is sufficient for the LED 59 to emit light. For this reason, when the bicycle 1 that has continued to travel has stopped due to a signal or the like, the lamp 54 is extinguished and the function of the headlamp 6 is lost, but the LED 59 remains lit and the front, side, and rear three Visible from the direction. Since the LED 59 that lights up in this way asserts the existence of the bicycle 1 to other bicycles, automobiles, pedestrians, etc., the safety of the passenger can be ensured.

  A conventional headlamp 100 is shown in FIGS. Components that are functionally common to the headlamp 6 shown in FIGS. 9 to 12 are denoted by the same reference numerals as those of the headlamp 6, and description thereof is omitted.

  The main components that are present in the headlamp 6 and are missing from the headlamp 100 are the light guide lens 56, the LED 59, and the capacitor 60. The lamp 54 also emits light laterally through the notch 53c formed in the reflecting mirror 53. However, when the bicycle 1 stops traveling and the hub dynamo 10 does not generate power, the lamp 54 does not emit light. Therefore, when the bicycle 1 is stopped from the running state at night, the safety of the passenger cannot be ensured as much as the headlamp 6.

  Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

  The present invention is widely applicable to a bicycle hub dynamo.

DESCRIPTION OF SYMBOLS 1 Bicycle 2 Front wheel 3 Handle 4 Front fork 5 Spoke 6 Headlamp 10 Hub dynamo 11 Hub shaft 12 Dynamo case 20 Stator unit 21 Iron core 21a Pole piece 22 Coil 30 Rotor unit 31 Rotor yoke 32 Magnet 40 Circuit board 41 Holder 42 Rectifier circuit 42a Output line

Claims (4)

A bicycle hub dynamo having a hub shaft and a dynamo case rotatably held on the hub shaft,
A stator unit fixed to the hub axle, and a rotor unit fixed to the dynamo case,
The stator unit is for three-phase AC power generation,
A bicycle hub dynamo characterized in that a circuit board including a rectifying circuit for converting a three-phase AC output of the stator unit into a DC output is disposed in the dynamo case.   The circuit board is supported by the hub shaft by a holder made of a conductive material, and the holder plays a role of electrically connecting one of a pair of output lines for taking out the DC output to the hub shaft. The bicycle hub dynamo according to claim 1.   The bicycle hub dynamo according to claim 1 or 2, wherein the iron core included in the stator unit is a laminated iron core.   The bicycle hub dynamo according to claim 3, wherein the number of poles of the iron core pole piece is different from the number of magnet poles included in the rotor unit.

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