Power generator

Abstract

To provide a power generator that can generate power with a simple structure.SOLUTION: A power generator 10 comprises: a crank arm 5; a rotor 9 fixed to the crank arm 5; a bracket 32; a stator 8 fixed to the bracket 32; bearings 31; and a crank shaft 4 supported on the bracket 32 with the bearings 31 therebetween.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a power generation device. [Background technology]

[0002] Patent Document 1 discloses a bottom bracket structure for a bicycle having an electricity generating mechanism. In this bottom bracket structure, a crankshaft is connected to a rotating part of the electricity generating mechanism via a planetary gear unit. The planetary gear unit allows the rotating part of the electricity generating mechanism to rotate faster than the crankshaft. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-15987 A Summary of the Invention [Problem to be solved by the invention]

[0004] The bottom bracket structure of Patent Document 1 incorporates a complex planetary gear unit and a power generation mechanism in order to obtain sufficient power generation performance. Such a bottom bracket structure is costly due to its complex structure. In addition, there is a concern about the increase in weight due to the incorporation of the planetary gear unit, etc.

[0005] SUMMARY OF THE PRESENT EMBODIMENTS Accordingly, an object of the present invention is to provide a power generating device capable of generating power with a simple structure. [Means for solving the problem]

[0006] A power generating device according to one embodiment of the present invention comprises a crank arm, a rotor fixed to the crank arm, a bracket, a stator fixed to the bracket, a bearing, and a crankshaft supported by the bracket via the bearing. [Brief description of the drawings]

[0007] [Figure 1] 1 is a perspective view showing a schematic structure of a crankset 1 incorporating a power generating device according to a first embodiment of the present invention. [Diagram 2] 1 is an exploded perspective view showing a schematic structure of a crankset 1 incorporating a power generating device according to a first embodiment of the present invention. [Diagram 3] FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. [Figure 4] FIG. 4 is a partially enlarged cross-sectional view of a portion of the cross-sectional view of FIG. [Diagram 5] FIG. 5 is a cross-sectional view taken along line 5-5 in FIG. [Figure 6] FIG. 11 is a perspective view showing a schematic structure of a crankset 1A incorporating a power generating device according to a second embodiment of the present invention. [Figure 7] FIG. 11 is an exploded perspective view showing a schematic structure of a crankset 1A incorporating a power generating device according to a second embodiment of the present invention. [Figure 8] FIG. 8 is a cross-sectional view taken along line 8-8 in FIG. 6. [Figure 9] FIG. 9 is a cross-sectional view taken along line 9-9 in FIG. 8. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view showing a schematic structure of a crankset 1 incorporating a power generating device according to a first embodiment of the present invention. FIG. 2 is an exploded perspective view showing a schematic structure of a crankset 1 incorporating a power generating device according to a first embodiment of the present invention. The crankset 1 is mounted on a bottom bracket shell 2 of a frame of, for example, a bicycle (including all types of bicycles such as road bikes, cross bikes, mountain bikes, and city bikes). For the sake of simplification, only the bottom bracket shell 2 of the frame that defines a cylindrical internal space is shown in FIG. 1 and FIG. 2. Although the bottom bracket shell 2 is shown to have a cylindrical outer shape, it is not limited to this shape and may have other shapes.

[0009] The crankset 1 includes a bottom bracket 3, a crankshaft 4, a right crank arm 5, a left crank arm 6, and a chain ring 7. The bottom bracket 3 is attached to a bottom bracket shell 2. The internal space of the bottom bracket shell 2 is opened through circular openings 21 and 22. The crankshaft 4 is supported by the bottom bracket 3 so as to be rotatable around an axis x. Most of the crankshaft 4 is housed within the bottom bracket 3, and one end 41 and the other end 42 of the crankshaft 4 protrude from the bottom bracket 3 in a direction along the axis x (hereinafter referred to as the "rotation axis direction"). The crankshaft 4, the right crank arm 5, and the left crank arm 6 are formed, for example, from a metal material.

[0010] The right crank arm 5 has a main body 51, a hole or mounting hole 52 formed in the main body 51 along the axis x, a plurality of portions (hereinafter referred to as "projections") 53 projecting from the main body 51 in a radial direction perpendicular to the axis x, and one arm main body 54 similarly projecting radially from the main body 51. In this example, the chain ring 7 is attached to the crankshaft 4 side of the main body 51 in the rotation axis direction. During attachment, a fastening part or bolt 72 is screwed into a hole or screw hole 55 formed in the projecting portion 53 through a hole or through hole 71 formed in the chain ring 7. In this example, four screw holes 55 and four through holes 71 are formed in the right crank arm 5 and the chain ring 7 at predetermined angular intervals around the axis x.

[0011] As is clear from Fig. 2, a sawtooth groove 43, for example, is formed on the outer peripheral surface of one end 41 of the crankshaft 4, while a sawtooth groove (not shown) is also formed on the inner peripheral surface of the mounting hole 52 of the right crank arm 5. These grooves 43 extend parallel to the axis x. The groove 43 and the groove of the mounting hole 52 are fitted together, so that the right crank arm 5 is attached to the one end 41 of the crankshaft 4 so as to be unable to rotate relative to it. Note that the right crank arm 5 may incorporate a mechanism (not shown) for preventing the crankshaft 4 from falling off the right crank arm 5. In addition, a pedal (not shown) is attached to the tip of an arm body 54 extending from a base end connected to the body 51.

[0012] On the other hand, the left crank arm 6 has an arm body 61 and a hole, i.e., a mounting hole 62, formed at the base end of the arm body 61. For example, a sawtooth groove 44 is formed on the outer peripheral surface of the other end 42 of the crankshaft 4, while a sawtooth groove (not shown) is also formed on the inner peripheral surface of the mounting hole 62 of the left crank arm 6. These grooves 44 extend parallel to the axis x. The groove 44 and the groove of the mounting hole 62 are fitted together, so that the left crank arm 6 is mounted to the other end 42 of the crankshaft 4 so as not to rotate relative to the left crank arm 6. Note that the left crank arm 6 may be incorporated with a mechanism (not shown) for preventing the crankshaft 4 from falling off the left crank arm 6. A pedal (not shown) is attached to the tip of the arm body 61 extending from the base end where the mounting hole 62 is formed.

[0013] 3 is a cross-sectional view taken along line 3-3 in FIG. 1. The bottom bracket 3 is a generally cylindrical member accommodated in a cylindrical space between a cylindrical outer peripheral side surface 45 centered on the axis x of the crankshaft 4 and a cylindrical inner peripheral surface 23 of the bottom bracket shell 2. The bottom bracket 3 has one or more (two in this example) bearings 31, 31, and a bracket 32. Each bearing 31 is, for example, a ball bearing. The bracket 32 ​​has a pair of outer peripheral sleeves (hereinafter referred to as "outer peripheral sleeves") 321, 321, and an inner peripheral sleeve (hereinafter referred to as "inner peripheral sleeve") 322. Both the outer peripheral sleeve 321 and the inner peripheral sleeve 322 are formed in a generally cylindrical shape.

[0014] The outer sleeves 321, 321 are fixed to the openings 21, 22 of the bottom bracket shell 2, respectively. Each outer sleeve 321 has a portion 321a (hereinafter referred to as the "fitting portion") that fits into the inner peripheral surface 23 of the bottom bracket shell 2, and a portion 321b (hereinafter referred to as the "flange portion") that protrudes radially from the fitting portion 321a toward the outer peripheral side. The fitting portion 321a is formed in a generally cylindrical shape centered on the axis x. The fitting portion 321a fits into the inner peripheral surface 23 of the bottom bracket shell 2 by, for example, press fitting. Each flange portion 321b is disposed adjacent to the openings 21, 22 outside the internal space of the bottom bracket shell 2. An outer ring of a bearing 31 is attached to the inner peripheral surface of each flange portion 321b by press fitting, adhesive, or the like. The inner ring of the bearing 31 is supported by the crankshaft 4. Moreover, the inner ring of each bearing 31 is in contact with the right crank arm 5 or the left crank arm 6 in the axial direction.

[0015] In the rotation axis direction, the ends of the inner sleeve 322 are fitted to the inner ends of the pair of outer sleeves 321. In this example, the outer peripheral surface of the inner sleeve 322 is fitted to the inner peripheral surface of the fitting portion 321a of the outer sleeve 321. A seal member 323 is sandwiched between the inner peripheral surface of the fitting portion 321a and the outer peripheral surface of the inner sleeve 322. This seal member 323 seals between the internal space and the external space of the inner sleeve 322. In the bracket 32, the outer sleeve 321 is fixed to the bottom bracket shell 2 by pressing the fitting portion 321a, but instead of this press-fit type, a screw type in which a thread groove is cut in the outer peripheral surface of the fitting portion 321a and the inner peripheral surface 23 of the bottom bracket shell 2 may be used.

[0016] 1 to 3, the stator 8 is fixed to the bottom bracket 3 adjacent to the main body 51 of the right crank arm 5. Specifically, the stator 8 is fixed to an outer peripheral surface 321c of a flange portion 321b of an outer peripheral sleeve 321 of the bottom bracket 3. The outer peripheral surface 321c is defined by, for example, a cylindrical surface centered on the axis x. This outer peripheral surface 321c faces an inner peripheral surface 321d on the crankshaft 4 side. In this example, the side opposite to the crankshaft 4 side is defined as the right crank arm 5 side. That is, the stator 8 is fixed to the outer peripheral surface 321c on the right crank arm 5 side opposite to the crankshaft 4. On the other hand, the bearing 31 is fixed to the inner peripheral surface 321d on the crankshaft 4 side opposite to the right crank arm 5.

[0017] A rotor 9 is disposed opposite the stator 8 in a radial direction perpendicular to the axis x. Specifically, as shown in Figs. 2 and 3, the rotor 9 is fixed to one side surface, i.e., inner surface 51a, of the body 51 of the right crank arm 5 on the crankshaft 4 side in the rotation axis direction. In this example, the inner surface 51a extends along, for example, an imaginary plane perpendicular to the axis x. Fig. 4 is a partially enlarged cross-sectional view of a part of the cross-sectional view of Fig. 3. Fig. 5 is a cross-sectional view taken along line 5-5 of Fig. 3. Note that in Fig. 5, the right crank arm 5 and the chain ring 7 are omitted for simplification. Referring to Figs. 4 and 5 together, the stator 8 has a magnetic body, i.e., a stator core 81, a coil 82, and an insulator 83.

[0018] The stator core 81 is formed of a laminate of magnetic materials such as silicon steel plates. The stator core 81 functions as a yoke of the stator 8. The stator core 81 has a cylindrical portion (hereinafter referred to as a "cylindrical portion") 84 centered on the axis x, and a plurality of (e.g., 18) teeth 85 extending radially outward from the outer circumferential surface of the cylindrical portion 84. The stator core 81 is attached to the outer circumferential surface 321c of the outer sleeve 321 at the inner circumferential surface 84a of the cylindrical portion 84. A coil 82 is wound around each tooth 85 so as to have a winding axis in the radial direction. An insulator 83 is disposed between the teeth 85 and the coil 82. The insulator 83 insulates the stator core 81 from the coil 82.

[0019] The rotor 9 facing the stator 8 in the radial direction has a magnet 91, a yoke 92, and a housing 93. The magnet 91 is a cylindrical permanent magnet centered on the axis x. The magnet 91 may be a single cylindrical permanent magnet, or may be formed into a cylindrical shape by connecting multiple permanent magnets in the circumferential direction. The cylindrical inner peripheral surface of the magnet 91 faces the outer peripheral surface of the teeth 85 of the stator core 81 with a predetermined magnetic gap. The cylindrical outer peripheral surface of the magnet 91 is fixed to the inner peripheral surface of a roughly cylindrical yoke 92 centered on the axis x, for example, by an adhesive or the like. The yoke 92 is formed of, for example, a magnetic material.

[0020] The housing 93 has a first housing 931 arranged on the right crank arm 5 side and a second housing 932 arranged on the left crank arm 6 side. The first housing 931 and the second housing 932 are both formed in an annular shape. The first housing 931 has, for example, a flat plate portion (hereinafter referred to as the "flat plate portion") 931a that spreads annularly along an imaginary plane perpendicular to the axis x, and a side wall portion (hereinafter referred to as the "side wall portion") 931b that spreads annularly from the outer circumferential end of the flat plate portion 931a toward the second housing 932 along the axis x. The first housing 931 is fixed to the inner surface 51a of the main body 51 by the flat plate portion 931a. For fixing, a fastening part (not shown), such as a bolt, is used.

[0021] The second housing 932 has, for example, a flat plate portion (hereinafter referred to as "flat plate portion") 932a that spreads annularly along a virtual plane perpendicular to the axis x, and a side wall portion (hereinafter referred to as "side wall portion") 932b that spreads annularly from the outer circumferential end of the flat plate portion 932a toward the first housing 931 along the axis x. The yoke 92 has its outer circumferential surface fixed to the inner circumferential surface of the side wall portion 931b of the first housing 931 and the inner circumferential surface of the side wall portion 932b of the second housing 932, for example by adhesive or the like. In this way, the first housing 931 and the second housing 932 as a whole define, for example, an annular accommodation space for accommodating the above-mentioned stator 8.

[0022] At least the right crank arm 5, rotor 9, bracket 32, bearing 31, stator 8, and crankshaft 4 described above constitute the power generating device 10 according to the first embodiment of the present invention. The power generating device 10 has wiring (not shown) in which a plurality of lead wires drawn from the coil 82 are bundled together. This wiring is electrically connected to, for example, electronic devices mounted on the bicycle. Examples of the electronic devices include, for example, lights, electric shifting, electric brakes, a cycle computer, and various sensors. The various sensors include sensors that can communicate with the cycle computer using, for example, a predetermined wireless communication standard. The wiring drawn from the coil 82 may be connected to, for example, an electrical component such as a capacitor with a power storage function.

[0023] When such a crankset 1 is installed in a bicycle, pedaling causes the right crank arm 5 and the left crank arm 6 to swing about the axis x. As a result, the crankshaft 4 rotates about the axis x. This rotation causes the stator 8 and the rotor 9 to rotate relative to each other. As a result, electrical energy is generated in the coil 82 due to magnetic interaction between the magnet 91 and the coil 82. The electrical energy thus generated is sent through wiring to electronic devices mounted on the bicycle. The electronic devices can be driven by this electrical energy. The electrical energy generated by the power generation device 10 may be temporarily stored in a power storage device such as a capacitor.

[0024] In the crankset 1 described above, the generator 10 is assembled adjacent to the bottom bracket shell 2. Specifically, the stator 8 and rotor 9 are disposed adjacent to the inner surface 51a of the right crank arm 5 outside the bottom bracket 3. The stator 8 is fixed to the bottom bracket 3, while the rotor 9 is fixed to the right crank arm 5. In this way, the generator 10 can generate electricity with a simple structure. The generator 10 does not have a complex structure that may increase the weight, so the increase in weight due to the assembly of the generator 10 can be suppressed. With such a generator 10, it is not necessary to mount a battery on the bicycle. This relieves the user from the trouble of charging the battery. In addition, if a battery is already mounted, the battery capacity can be reduced to reduce the weight of the battery itself. Alternatively, the battery capacity can be kept the same, and the use of the electricity stored in the battery can be dedicated to assisting the bicycle, thereby increasing the range of the assisted bicycle itself.

[0025] Next, a scene in which the above-mentioned crankset 1 is mounted on the bottom bracket shell 2 will be described. First, the bottom bracket 3 is mounted on the bottom bracket shell 2. Specifically, an outer peripheral sleeve 321 on the right crank arm 5 side to which the bearing 31 and the stator 8 are attached, and an outer peripheral sleeve 321 on the left crank arm 6 side to which the bearing 31 and the seal member 33 are attached are fixed to the openings 21 and 22 of the bottom bracket shell 2, respectively. An inner peripheral sleeve 322 is supported on one of the outer peripheral sleeves 321. Then, the crankshaft 4, which has the right crank arm 5 to which the chain ring 7, the first housing 931, the magnet 91, and the yoke 92 are already attached, is mounted by insertion or the like in the bottom bracket 3. After the second housing 932 is attached to the yoke 92, the left crank arm 6 is attached to the other end 42 of the crankshaft 4. In this manner, the crankset 1 is mounted on the bottom bracket shell 2.

[0026] FIG. 6 is a perspective view showing a schematic structure of a crankset 1A incorporating a power generating device according to a second embodiment of the present invention. FIG. 7 is an exploded perspective view showing a schematic structure of a crankset 1A incorporating a power generating device according to a second embodiment of the present invention. Referring to both FIG. 6 and FIG. 7, the crankset 1A includes a bottom bracket 3, a crankshaft 4, a right crank arm 5A, a left crank arm 6, and a chain ring 7. That is, compared to the above-mentioned crankset 1, the structure of the right crank arm 5A is different from the structure of the right crank arm 5. Other components similar to those of the crankset 1 of the above-mentioned first embodiment are given the same reference numerals, and duplicated explanations will be omitted here.

[0027] Compared with the structure of the crank arm 5 according to the first embodiment, specifically, a housing 931 of the rotor 9 of the crankset 1 according to the first embodiment is integrally formed with the right crank arm 5A. As specifically shown in FIG. 7, a recess 56 for accommodating the stator 8 and the rotor 9 is formed in the body 51 of the right crank arm 5A. In this example, the recess 56 defines a flat cylindrical accommodation space centered on the axis x. A magnet 91 and a yoke 92 constituting the rotor 9 are fixed to the inner circumferential surface of a side wall 57 of the body 51 that forms the recess 56.

[0028] Fig. 8 is a cross-sectional view taken along line 8-8 in Fig. 6. Fig. 9 is a cross-sectional view taken along line 9-9 in Fig. 8. Referring to Figs. 6 to 9 together, similarly to the first embodiment, the stator 8 is fixed to the outer peripheral surface 321c of the outer peripheral sleeve 321 of the bottom bracket 3. The stator 8 has a stator core 81, a coil 82, and an insulator 83. A magnet 91 fixed to the side wall 57 of the recess 56 of the main body 51 faces the stator 8 in the radial direction with a predetermined magnetic gap therebetween.

[0029] The rotor 9 has a housing 94 that covers the recess 56. The housing 94 has a flat annular plate portion (hereinafter referred to as the "flat plate portion") 941 that is flat around the axis x, and a protrusion 942 that protrudes radially from the outer periphery of the flat plate portion 941. A hole, i.e., a through hole 943 that extends parallel to the axis x is formed in the protrusion 942. A fastening part, i.e., a bolt 95, is screwed through the through hole 943 into a hole, i.e., a screw hole 58, formed in the protrusion 53 of the main body 51, thereby fixing the housing 94 to the right crank arm 5A. The flat plate portion 941 of the housing 94 covers the recess 56 around the bottom bracket 3.

[0030] At least the above-mentioned right crank arm 5A, rotor 9, bracket 32, bearing 31, stator 8, and crankshaft 4 constitute a power generating device 10A according to a second embodiment of the present invention. In such a crankset 1A, the power generating device 10A is assembled adjacent to the bottom bracket shell 2, similar to the crankset 1. Specifically, the stator 8 and rotor 9 are disposed in a recess 56 of the right crank arm 5A outside the bottom bracket 3. The stator 8 is fixed to the bottom bracket 3, while the rotor 9 is fixed to the right crank arm 5A. In this way, the power generating device 10A can generate electricity with a simple structure.

[0031] Next, a scene in which the above-mentioned crankset 1A is mounted on the bottom bracket shell 2 will be described. First, the bottom bracket 3 is mounted on the bottom bracket shell 2. Specifically, an outer peripheral sleeve 321 on the right crank arm 5 side to which the bearing 31 and the stator 8 are attached, and an outer peripheral sleeve 321 on the left crank arm 6 side to which the bearing 31 is attached, are fixed to the openings 21 and 22 of the bottom bracket shell 2, respectively. An inner peripheral sleeve 322 is supported on one of the outer peripheral sleeves 321. Then, the crankshaft 4, which has the right crank arm 5A to which the chain ring 7, the magnet 91, and the yoke 92 are already attached, attached to one end 41 in advance, is attached by inserting it into the bottom bracket 3. After the housing 94 is attached to the right crank arm 5A, the left crank arm 6 is attached to the other end 42 of the crankshaft 4. In this manner, the crankset 1A is mounted on the bottom bracket shell 2.

[0032] Although the present invention has been described above through the above embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is clear to those skilled in the art that various modifications or improvements can be made to the above embodiments. It is clear from the claims that such modifications or improvements can also be included in the technical scope of the present invention.

[0033] The above-described embodiments are intended to facilitate understanding of the present invention, and are not intended to limit the present invention. The components of the above-described embodiments, as well as their arrangements, materials, conditions, shapes, sizes, etc., are not limited to those illustrated, and can be modified as appropriate. Furthermore, components shown in different embodiments can be partially substituted or combined with each other within the scope of technical inconsistency. [Explanation of symbols]

[0034] 1, 1A crank set, 2 bottom bracket shell, 21 opening, 22 opening, 3 bottom bracket, 31 bearing, 32 bracket, 321 outer sleeve (outer sleeve), 321a mating portion (mating portion), 321b protruding portion (flange portion), 321c outer surface, 322 inner sleeve (inner sleeve), 323 seal member, 4 crankshaft, 41 one end, 42 other end, 43 groove, 44 groove, 45 outer side surface, 5, 5A right crank arm, 51 main body, 51a one side surface (inner surface), 52 hole (mounting hole), 53 protruding portion (protruding portion), 54 arm main body, 55 hole (screw hole), 56 recess, 57 side wall, 58 hole (screw hole), 6 left crank arm, 61 arm main body, 62 hole (mounting hole), 7 chain ring, 71 through hole, 72 fastening part (bolt), 8 stator, 81 magnetic body (stator core), 82 coil, 83 insulator, 84 cylindrical part (cylindrical part), 84a inner peripheral surface, 85 teeth, 9 rotor, 91 magnet, 92 yoke, 93 housing, 931 first housing, 931a flat plate part (flat plate part), 931b side wall part (side wall part), 932 second housing, 932a flat plate part (flat plate part), 932b side wall part (side wall part), 94 housing, 941 flat plate part (flat plate part), 942 protrusion, 943 hole (through hole), 95 fastening part (bolt), 10, 10A power generating device, x-axis line

Claims

1. A crank arm, A rotor fixed to the crank arm; A bracket and A stator fixed to the bracket; A bearing, a crankshaft supported by the bracket via the bearing.

2. The power generating device of claim 1 , wherein the rotor comprises a magnet.

3. The power generating device according to claim 1 , wherein the stator comprises a magnetic body and a coil wound around the magnetic body.

4. The power generating device according to claim 1 , wherein the rotor is fixed to a surface of the crank arm on a side facing the crankshaft.

5. The power generating device according to claim 1 , wherein the stator is fixed to a surface of the bracket on a side facing the crank arm.

6. The power generating device according to claim 1 , wherein the bearing is fixed to a surface of the bracket on a side facing the crankshaft.

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