Self-powered device, bicycle and indoor exercise bike

Abstract

A self-powered device, a bicycle and an indoor exercise bicycle, the self-powered device is a pedaling and rotating device for riding, the self-powered device comprises a pedaling unit, a shaft, a generator and an energy storage element. The pedaling unit comprises an inner surface to form a containing space therein. The shaft is contained in the containing space. The generator comprises a stator and a rotor, wherein the stator is arranged on the shaft, and the rotor is arranged on the inner surface of the pedaling unit, the rotor correspondingly surrounds the stator and does not contact the stator. The energy storage element is electrically coupled with the generator. When the pedaling unit is rotated by the pedaling of the rider, the stator is fixed on the shaft, the rotor rotates relative to the stator with the pedaling unit, the generator generates power to charge the energy storage element. In this way, the service life of the energy storage element can be prolonged.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a self-powered device, a bicycle and an indoor exercise bike, and in particular, to a self-powered device as a power pedal, and a bicycle and an indoor exercise bike comprising the power pedal. BACKGROUND

[0002] With the increasing popularity of health and sports activities, a bicycle or an indoor exercise bike is usually equipped with a conventional or known power pedal having at least one strain gauge or similar sensor for measuring riding data to provide the rider's physical and riding information while the rider is riding. However, it is inconvenient for the rider to frequently replace or remove the battery of the power pedal for charging. Therefore, there is indeed a need or motivation for the conventional or known power pedal to improve the convenience of battery charging. SUMMARY

[0003] The present disclosure provides a self-powered device, a bicycle and an indoor exercise bike, by arranging a generator in a limited accommodation space of the self-powered device, wherein a stator of the generator is arranged on an axis, and a rotor is arranged on an inner surface of a pedaling unit, the stator is fixed on the axis, and the rotor rotates relative to the stator as the pedaling unit is rotated by a rider pedaling, the generator generates power to charge an energy storage element, thereby prolonging the use time of the energy storage element and further avoiding the inconvenience caused by frequent replacement of the energy storage element.

[0004] According to an embodiment of the present disclosure, a self-powered device is provided for a pedaling and rotating device for riding, the self-powered device comprising a pedaling unit, an axis, a generator, an energy storage element, at least one sensor, and at least one circuit board. The pedaling unit comprises an inner surface to form an accommodation space therein. The axis is accommodated in the accommodation space and comprises a main body portion and a base portion, the main body portion is arranged closer to at least one pedal of the pedaling unit than the base portion. The generator comprises a stator and a rotor, wherein the stator is arranged on the axis, and the rotor is arranged on the inner surface of the pedaling unit, the rotor correspondingly surrounds the stator and does not contact the stator. The energy storage element is electrically coupled to the generator and adjacent to the base portion, the energy storage element is arranged in the accommodation space of the axis surrounded by the inner surface of the axis of the base portion. The at least one sensor is powered by the energy storage element and adjacent to the base portion. The at least one circuit board is arranged around the base portion, the at least one circuit board supports a rectification circuit for the energy storage element and a power supply circuit for the sensor. When the pedaling unit is rotated by a rider pedaling, the stator is fixed on the axis, and the rotor rotates relative to the stator as the pedaling unit is rotated, the generator generates power to charge the energy storage element.

[0005] In an embodiment of the self-powered device according to the foregoing embodiment, the stator can include a plurality of stator teeth and a plurality of stator coils, the plurality of stator coils being wound on the plurality of stator teeth, respectively. The rotor can include a rotor yoke and a plurality of rotor magnets attached on the rotor yoke in sequence along an inner surface of the rotor yoke, an arc length of each stator tooth being less than or equal to an arc length of each rotor magnet.

[0006] In an embodiment of the self-powered device according to the foregoing embodiment, the stepping unit can further include a stepping body, the at least one stepping plate being connected to the stepping body and extending along a vertical direction of the axis, the stepping body being tubular in nature, an inner surface of the stepping body including a body inner surface located on an inner surface of the stepping body, a body portion being located within the body inner surface. The stator is disposed on the body portion of the axis, and the rotor is disposed on the body inner surface.

[0007] In an embodiment of the self-powered device according to the foregoing embodiment, an outer diameter of the generator can be in a range of 10 mm to 30 mm, and a thickness of the generator can be in a range of 20 mm to 60 mm.

[0008] In an embodiment of the self-powered device according to the foregoing embodiment, a number of the stator teeth can be in a range of 3 to 12, and a number of the rotor magnets can be in a range of 2 to 16.

[0009] In an embodiment of the self-powered device according to the foregoing embodiment, an air gap between the stator and the rotor can be in a range of 0.10 mm to 0.30 mm, and a number of turns of each stator coil can be in a range of 250 turns to 500 turns.

[0010] In an embodiment of the self-powered device according to the foregoing embodiment, the stepping unit can further include a stepping body and a stepping shell, the at least one stepping plate being connected to the stepping body and extending along a vertical direction of the axis, the stepping shell being connected to the stepping body, the stepping shell and the stepping body being tubular in nature, an inner surface of the stepping shell including a shell inner surface located on an inner surface of the stepping shell, a shell portion being located within the shell inner surface. The stator is disposed on the shell portion of the axis, and the rotor is disposed on the shell inner surface.

[0011] In an embodiment of the self-powered device according to the foregoing embodiment, an outer diameter of the generator can be in a range of 20 mm to 40 mm, and a thickness of the generator can be in a range of 5 mm to 20 mm.

[0012] In an embodiment of the self-powered device according to the foregoing embodiment, a number of the stator teeth can be in a range of 3 to 18, and a number of the rotor magnets can be in a range of 2 to 22.

[0013] In an embodiment of the self-powered device according to the foregoing embodiment, the air gap between the stator and the rotor can be in the range of 0.10 mm to 0.30 mm, and the number of turns of each stator coil can be in the range of 150 turns to 400 turns.

[0014] In an embodiment of the self-powered device according to the foregoing embodiment, when the pedaling rate of the rotor is in the range of 60 rpm to 80 rpm, the generated power output by the generator can be in the range of 3.4 mW to 11.8 mW. When the pedaling rate of the rotor is in the range of 80 rpm to 100 rpm, the generated power output by the generator can be in the range of 8.1 mW to 21.7 mW. When the pedaling rate of the rotor is in the range of 100 rpm to 120 rpm, the generated power output by the generator can be in the range of 14.7 mW to 34.5 mW. The rectifier circuit can be configured between the generator and the energy storage element, and the rectified voltage output by the rectifier circuit can be in the range of 0.5 VDC to 9 VDC.

[0015] In an embodiment of the self-powered device according to the foregoing embodiment, when the pedaling rate of the rotor is in the range of 60 rpm to 120 rpm, the generated power output by the generator can increase by at least 20% for each 10 rpm increase in the pedaling rate.

[0016] In an embodiment of the self-powered device according to the foregoing embodiment, the at least one sensor can be a strain gauge, the number of the at least one sensor can be at least two, and the number of the at least one circuit board can be at least two. The sensors and the circuit boards can be alternately and symmetrically arranged around the base portion of the shaft.

[0017] In an embodiment of the self-powered device according to the foregoing embodiment, the circuit board can be a ring-shaped printed circuit board surrounding the base portion, and a normal direction of a surface of the circuit board can be parallel to the base portion.

[0018] In an embodiment of the self-powered device according to the foregoing embodiment, the self-powered device can not include a speed increasing mechanism and a speed decreasing mechanism.

[0019] According to another embodiment of the disclosure, a bicycle is provided, which includes the self-powered device according to the foregoing embodiment, wherein the self-powered device is a power pedal device of the bicycle.

[0020] According to still another embodiment of the disclosure, an indoor exercise bike is provided, which includes the self-powered device according to the foregoing embodiment, wherein the self-powered device is a power pedal device of the indoor exercise bike. BRIEF DESCRIPTION OF DRAWINGS

[0021] FIG. 1A FIG. 1 shows a perspective view of a self-powered device according to a first embodiment of the disclosure;

[0022] FIG. 1Bexploded view FIG. 1A exploded view of the self-powered device of the first embodiment;

[0023] FIG. 1C exploded view FIG. 1A longitudinal sectional view of the self-powered device of the first embodiment;

[0024] FIG. 1D exploded view FIG. 1C sectional view along section line 1D-1D;

[0025] FIG. 1E exploded view FIG. 1C sectional view along section line 1E-1E;

[0026] FIG. 1F exploded view of the generator of the self-powered device of the first embodiment;

[0027] FIG. 1G exploded view FIG. 1D schematic diagram of the generator parameters of the self-powered device of the first embodiment;

[0028] FIG. 1H block diagram of the self-powered device of the first embodiment;

[0029] FIG. 1I schematic diagram of the generator output power of the self-powered device of the first embodiment corresponding to different pedaling frequency rates;

[0030] FIG. 1J schematic diagram of the rectified voltage output by the rectifier circuit of the self-powered device of the first embodiment corresponding to different pedaling frequency rates;

[0031] FIG. 2A exploded view of the self-powered device of the second embodiment of the present disclosure;

[0032] FIG. 2B exploded view FIG. 2A exploded view of the self-powered device of the second embodiment;

[0033] FIG. 2C exploded view FIG. 2A longitudinal sectional view of the self-powered device of the second embodiment;

[0034] FIG. 2D exploded view FIG. 2C sectional view along section line 2D-2D;

[0035] FIG. 2E exploded view FIG. 2C sectional view along section line 2E-2E;

[0036] FIG. 3A exploded view of the self-powered device of the third embodiment of the present disclosure;

[0037] FIG. 3B Draw FIG. 3A Exploded view of the self-powered device in the third embodiment;

[0038] FIG. 3C Draw FIG. 3A Longitudinal cross-sectional view of the self-powered device in the third embodiment;

[0039] FIG. 3D Draw FIG. 3C 3D-3D cross-sectional view along the central section line;

[0040] FIG. 3E A perspective view of the generator of the self-powered device according to the third embodiment is shown;

[0041] FIG. 3F Draw FIG. 3E Side view of the generator of the self-powered device in the third embodiment;

[0042] FIG. 3G Draw FIG. 3E A schematic diagram of the parameters of the generator in the self-powered device of the third embodiment;

[0043] FIG. 3H A schematic diagram illustrating the generator output power of the self-powered device of the third embodiment corresponding to different cadence rates is shown.

[0044] FIG. 3I A schematic diagram illustrating the rectified voltage output by the rectifier circuit of the self-powered device in the third embodiment corresponding to different tread speeds is shown.

[0045] FIG. 4 A schematic diagram illustrating the bicycle of the fourth embodiment of this disclosure; and

[0046] FIG. 5 A schematic diagram of an indoor exercise bike according to the fifth embodiment of this disclosure is shown.

[0047] [Symbol Explanation]

[0048] 40: Bicycle

[0049] 50: Indoor exercise bike

[0050] 100, 200, 300: Self-powered devices

[0051] 104, 204, 304: Generators

[0052] 106: Rectifier Circuit

[0053] 107: DC-DC converter circuit

[0054] 108: Power Supply Circuit

[0055] 110, 210, 310: Tread unit

[0056] 111, 211, 311: Inner surface

[0057] 112, 212, 312: Main body inner surface

[0058] 115, 215, 315: Housing space

[0059] 116, 216, 316: Pedal

[0060] 120, 220, 320: Tread main body

[0061] 140, 240, 340: Shaft center

[0062] 142, 242, 342: Main body portion

[0063] 143, 243, 343: Root portion

[0064] 146, 246, 346: Shaft center inner surface

[0065] 150, 250, 350: Stator

[0066] 157, 257, 357: Stator tooth

[0067] 158, 258, 358: Stator coil

[0068] 160, 260, 360: Rotor

[0069] 166, 266, 366: Yoke inner surface

[0070] 167, 267, 367: Rotor yoke

[0071] 168, 268, 368: Rotor magnet

[0072] 171, 271, 371: End cap

[0073] 172, 272, 372: Bearing

[0074] 174, 274: Shaft center housing

[0075] 175, 176, 275, 276, 375: Circuit board

[0076] 178, 278: Sensor

[0077] 179, 279, 379: Energy storage element

[0078] 313: Root inner surface

[0079] 330: Stepping on the base shell

[0080] a5: Arc length of each stator tooth

[0081] a6: Arc length of each rotor magnet

[0082] d4: Outer diameter of the generator

[0083] t4: Thickness of the generator

[0084] t6: Thickness of each rotor magnet

[0085] g4: Air gap between stator and rotor

[0086] w5: Width of each stator tooth

[0087] r5: Outer radius of the stator

[0088] r7: Inner radius of the stator Detailed Implementation

[0089] FIG. 1A A perspective view of a self-powered apparatus 100 according to the first embodiment of this disclosure is shown. FIG. 1B Draw FIG. 1A An exploded view of the self-powered device 100 of the first embodiment. FIG. 1C Draw FIG. 1A A longitudinal cross-sectional view of the self-powered device 100 according to the first embodiment. Please refer to... FIG. 1A to FIG. 1C The self-powered device 100 is a device for cycling, such as a power pedal apparatus for a bicycle or indoor exercise bike, and more particularly, a device that generates electricity during pedaling and rotation (i.e., rotation). In other words, the self-powered device 100 is a pedaling and rotational device for cycling. The self-powered device 100 includes a pedaling unit 110, a shaft 140, a generator 104, and an energy storage element 179 (e.g., a battery). The pedaling unit 110 includes an inner surface 111 that forms and surrounds a receiving space 115 therein; or, more specifically, the pedaling unit 110 includes the receiving space 115 and forms the inner surface 111 therein. The opening of the pedaling unit 110 can be closed by an end cap 171, and the shaft 140 is received within the receiving space 115.

[0090] FIG. 1D Draw FIG. 1C A cross-sectional view along section line 1D-1D. FIG. 1E Draw FIG. 1C Cross-sectional view along section line 1E-1E. Please refer to... FIG. 1B to FIG. 1EThe generator 104 at least comprises a stator 150 and a rotor 160, wherein the stator 150 is disposed on the shaft 140, the rotor 160 is disposed on the inner surface 112 of the main body 120, the rotor 160 correspondingly surrounds the stator 150 and does not contact the stator 150, wherein the inner surface 112 is a part of the inner surface 111 and is used to receive and mount the rotor 160. The energy storage element 179 is electrically coupled to the generator 104. When the pedaling unit 110 is rotated by the rider pedaling, the stator 150 is fixed on the shaft 140, the rotor 160 rotates with the pedaling unit 110 relative to the stator 150 (i.e. the rotor 160 rotates with the pedaling unit 110 and rotates relative to the stator 150), the generator 104 generates power to charge the energy storage element 179. Thus, the present disclosure proposes "a self-powered device (such as a power pedal device of a bicycle or an indoor exercise bike) with active power supply, which comprises a power generation device (i.e. a generator) for energy collection", aiming to prolong the use time of the power supply of the self-powered device, and the technical means is to set a "micro-generator" in the limited space of the pedaling main body or the pedaling shell, which will be described in the embodiments of the present disclosure. The natural or inherent motion state of the rider pedaling the power pedal device makes the power pedal device in a rotating state, which drives the generator to generate power and charges the battery of the power pedal device, thereby prolonging the use time of the battery or power supply.

[0091] In detail, the pedaling unit 110 can further comprise a pedaling main body 120 and at least one pedal 116. Specifically, the number of the at least one pedal 116 is two, the two pedals 116 are connected to the pedaling main body 120 and respectively extend along two ends of the vertical direction of the shaft 140, and the two pedals 116 can be selected from a self-locking pedal (also known as a self-locking pedal) as an example. The pedaling main body 120 is tubular in nature (i.e. the accommodation space 115 formed therein is columnar, cylindrical or tubular in nature). The inner surface 111 comprises a main body inner surface 112 located on the inner surface of the pedaling main body 120, and the shaft 140 comprises a main body portion 142 located inside the main body inner surface 112. The stator 150 of the generator 104 is disposed on the main body portion 142 of the shaft 140, and the rotor 160 is disposed on the main body inner surface 112 of the inner surface 111. Thus, the generator 104 is beneficial to save power consumption and obtain greater power by utilizing the inherent rotation characteristics of the self-powered device 100, while neither increasing the overall volume nor changing the appearance of the self-powered device 100.

[0092] The self-powered device 100 can further include at least one sensor 178 (e.g., eight sensors 178 or four sensor groups) powered by the energy storage element 179. The axle core 140 includes a body portion 142 and a base portion 143, the body portion 142 being disposed closer to the two pedals 116 of the treadle unit 110 than the base portion 143. When the bicycle includes the self-powered device 100 as its power treadle device, the body portion 142 is located between the two bearings 172, the base portion 143 is adjacent to the crank arms of the bicycle, and the energy storage element 179 and the sensors 178 are adjacent to the base portion 143. In this way, the component arrangement and circuit layout of the self-powered device 100 facilitate efficient power generation without affecting the original treadle performance.

[0093] FIG. 1F FIG. 1 illustrates a perspective view of the generator 104 of the self-powered device 100 of the first embodiment, FIG. 1G FIG. 2 illustrates a schematic diagram of the generator 104 of the self-powered device 100 of the first embodiment. Please refer to FIG. 1D FIG. 3 illustrates a schematic diagram of the parameters of the generator 104 of the self-powered device 100 of the first embodiment. Please refer to FIG. 1F and FIG. 1G The stator 150 of the generator 104 can include a plurality of stator teeth 157 and a plurality of stator coils 158, the plurality of stator coils 158 being wound on the plurality of stator teeth 157, respectively. The rotor 160 of the generator 104 can include a rotor yoke (i.e., a fixed ring) 167 and a plurality of rotor magnets 168, the plurality of rotor magnets 168 being attached or affixed on the yoke inner surface 166 of the cylindrical rotor yoke 167 in sequence, the arc length a5 of each stator tooth 157 being less than or equal to (as shown in the first embodiment) the arc length a6 of each rotor magnet 168. In this way, the generator 104 can effectively induce power generation due to the change of the magnetic field. In detail, since the magnetic field from each rotor magnet 168 is not interrupted when the rotor 160 rotates relative to the stator 150, the micro generator 104 disposed in a limited volume can obtain more excitation, thereby directly increasing the total power generation. FIG. 1G

[0094] ​In the first embodiment of the present disclosure, the number of stator teeth 157 can be in the range of 3 to 12 (inclusive, and the range endpoints are included in the relevant description of the present disclosure) or in the range of 4 to 8, the number of rotor magnets 168 can be in the range of 2 to 16 or in the range of 6 to 10. The outer diameter d4 of the generator 104 can be in the range of 10 mm to 30 mm or in the range of 17 mm to 23 mm, the thickness t4 of the generator 104 can be in the range of 20 mm to 60 mm or in the range of 28 mm to 36 mm. The air gap g4 between the stator 150 and the rotor 160 can be in the range of 0.10 mm to 0.30 mm or in the range of 0.12 mm to 0.18 mm, the number of turns (winding number) of each stator coil 158 can be in the range of 250 turns to 500 turns or in the range of 330 turns to 360 turns. In this way, one of the key problems to be overcome by the present disclosure is to overcome the difficulty of designing a suitable generator 104 in a limited space to generate sufficient electric power to charge the energy storage element 179, and the power generated by the micro-generator 104 is generally proportional to the size or volume of the generator 104 itself. Various parameters of the generator 104, such as the number of pole pairs, the number of winding turns, the thickness, the length, etc., should be properly designed to optimize and achieve sufficient induced voltage level for successful charging, thereby avoiding or preventing the generator 104 from becoming a power consumption load due to insufficient power generation.

[0095] In particular, please refer to FIG. 1F and FIG. 1G , the generator 104 forming an alternating three-phase structure is disposed on the pedaling body 120 corresponding to the main body 142 of the shaft 140, and includes 6 slots and 8 poles as an example. The stator 150 has 6 teeth, the rotor 160 has 8 poles, and the number of turns of each stator coil 158 is 345 turns. The magnet material of each rotor magnet 168 is neodymium iron boron (NdFeB) and its magnetic grade is N42, and other magnet materials with suitable magnetic grade can also be used. Generally speaking, the stronger the magnetic field strength corresponding to the magnetic grade of the magnet material, the higher the power generation efficiency of the generator 104. The arc length of each stator tooth 157 is a5, the arc length of each rotor magnet 168 is a6, the outer diameter of the generator 104 is d4, the thickness of the generator 104 is t4, the thickness of each rotor magnet 168 is t6, the air gap (length) between the stator 150 and the rotor 160 is g4, the (root) width of each stator tooth 157 is w5, the outer radius of the stator 150 is r5, the inner radius of the stator 150 (i.e. the radius of the main body 142 of the shaft 140) is r7, and the values of the aforementioned parameters shown in the first embodiment of FIG. 1F and FIG. 1G are listed in Table 1 below.

[0096]

[0097]

[0098] FIG. 1H A block diagram illustrating the self-powered device 100 of the first embodiment is shown below. FIG. 1B , FIG. 1C , FIG. 1E and FIG. 1H The self-powered device 100 may further include at least one circuit board (specifically circuit boards 175 and 176) disposed around the base 143. Circuit boards 175 and 176 are electrically coupled to support (or carry) a rectifier circuit 106 for the energy storage element 179, a DC-DC converter circuit 107, and a power supply circuit 108 for the sensor 178. The energy storage element 179 is disposed within an axial accommodating space surrounded by the axial inner surface 146 of the base 143; that is, the base 143 of the shaft 140 includes the axial accommodating space and forms the axial inner surface 146 therein. Since the generated power can be used to charge the energy storage element 179, it is beneficial to avoid frequently removing the battery of the power pedal device for charging, thereby improving its power usage time and battery charging convenience. Specifically, the rectifier circuit 106 includes a rectifier or regulator to rectify or regulate the induced back electromotive force voltage generated by the three-phase alternator 104. A DC-DC converter circuit 107, including a DC-DC converter, is used to step down or boost the rectified voltage to a DC-DC voltage with an appropriate voltage level. Then, an energy storage element 179 and its battery management system (BMS) are used to store and manage the storage capacity of the energy storage element 179 to power the sensor 178. Additionally, the wiring connecting the generator 104, circuit boards 175, 176, energy storage element 179, and sensor 178 is omitted from the accompanying drawings. An external charging interface (e.g., a USB port) electrically coupled to the energy storage element 179 may also be provided as a charging option, allowing external charging of the energy storage element 179.

[0099] In the first embodiment, the circuit boards 175, 176 and the sensors 178 are adjacent to the base 143 and are surrounded by the shaft housing 174 which is not connected to the treadle unit 110 and can be fixed around the base 143 and not rotate with the treadle unit 110. By way of example but not limitation, the circuit boards 175 are printed circuit boards, the number of the circuit boards 175 is four, and the four circuit boards 175 are regularly and symmetrically arranged around the base 143 of the shaft 140. The circuit board 176 is a ring-shaped flexible printed circuit board (FPCB, Flexible PCB or Flexible Printed Circuit) to surround and attach on the base 143, and the number of the circuit board 176 is one. In other embodiments of the present disclosure, at least one printed circuit board and at least one flexible printed circuit board can be connected together to form a ring-shaped circuit carrier to surround the base of the shaft.

[0100] Each sensor 178 can be a strain gauge to measure the pedaling power of the rider when pedaling. By way of example but not limitation, the number of the sensors 178 is at least two and specifically eight, each two of the sensors 178 form a sensor group, as shown in FIG. 1B and FIG. 1C , so that the number of the sensor groups is four. The number of the circuit boards 175 is at least two and specifically four, and the four sensor groups and the four circuit boards 175 are alternately and symmetrically arranged around the base 143 of the shaft 140, as shown in FIG. 1E . By this way, when the self-powered device 100 includes the generator 104, the self-powered device 100 can still be advantageously rotated smoothly.

[0101] FIG. 1I a diagram showing the output power of the generator 104 of the self-powered device 100 of the first embodiment corresponding to different pedaling frequency rates, FIG. 1J a diagram showing the output voltage of the rectifier circuit 106 of the self-powered device 100 of the first embodiment corresponding to different pedaling frequency rates. Please refer to FIG. 1H to FIG. 1Jrpm, and the step rate less than or equal to 60 rpm generally corresponds to a Transient state, the power generation output by the generator 104 can generally range from 3.4 mW to 34.5 mW or from 3.4 mW to 23.1 mW. In detail, when the step rate of the rotor 160 ranges from 60 rpm to 80 rpm, the power generation output by the generator 104 can range from 3.4 mW to 8.1 mW; when the step rate of the rotor 160 ranges from 80 rpm to 100 rpm, the power generation output by the generator 104 can range from 8.1 mW to 14.7 mW; and when the step rate of the rotor 160 ranges from 100 rpm to 120 rpm, the power generation output by the generator 104 can range from 14.7 mW to 23.1 mW. The rectifier circuit 106 can be configured between the generator 104 and the energy storage element 179, and the rectifier voltage output by the rectifier circuit 106 can range from 0.5 VDC to 9 VDC, from 0.9 VDC to 2.8 VDC, or from 1.01 VDC to 2.6 VDC, depending on the various parameters designed for the generator 104. The DC conversion voltage output by the DC conversion circuit 107 can range from 4.15 VDC to 4.2 VDC. In this way, the generator 104 designed within the limited space of the self-powered device 100 is advantageous in generating sufficient power and appropriate voltage to effectively charge the energy storage element 179, and in turn power the sensor 178 disposed therein.

[0102] In the first embodiment, the relationship between the step rate of the Transient, 70, 80, 90, 100, 110, and 120 (rpm) and the power generation output by the generator 104 can be as shown in FIG. 2, FIG. 1I FIG. 1I The average power generation of all curves corresponding to the step rate in the Transient, 70, 80, 90, 100, 110, and 120 (rpm) is shown in Table 2 below, where the average power generation shown is calculated from the values at 400 ms to 500 ms in the steady state, FIG. 1I and Table 2 shows that the specific power generation at a step rate of 70 rpm is about 5.5 mW. The relationship between the step rate of the Transient, 70, 80, 90, 100, 110, and 120 (rpm) and the rectifier voltage output by the rectifier circuit 106 can be as shown in FIG. 3, FIG. 1J FIG. 1J ​​The average rectified voltage of all curves corresponding to the pedaling rate is shown in Table 3 below, in which the average rectified voltage shown is calculated from the values at 400 ms to 500 ms of the steady state. In general, the higher the pedaling rate, the higher the power generation efficiency of the generator 104. However, the pedaling rate of the user or rider is always limited. The generator 104 of the present disclosure does not require a speed-up or speed-down adjustment mechanism, but only needs to be properly designed with various parameters to achieve a sufficient induced voltage level, thereby generating sufficient charging power. After the induced back-EMF generated by the generator 104 is rectified by the rectification circuit 106, and is boosted and stabilized by the DC conversion circuit 107, the DC conversion voltage with a proper voltage level can be output by the DC conversion circuit 107 and input to the energy storage element 179, thereby charging the energy storage element 179.

[0103] When the pedaling rate of the rotor 160 is in the range of 60 rpm to 120 rpm, the power generation power output by the generator 104 can be increased by at least 20% for each 10 rpm increase in the pedaling rate. As an example but not by way of limitation, when the pedaling rate is increased from 70 rpm to 80 rpm, i.e., the pedaling rate is increased by 10 rpm from 70 rpm, the power generation power output by the generator 104 can be increased by 47.27%. In detail, as shown in Table 2, the power generation power is 5.5 mW when the pedaling rate is 70 rpm, and the power generation power is 8.1 mW when the pedaling rate is 80 rpm. Therefore, when the pedaling rate is increased by 10 rpm from 70 rpm (calculated from 80 rpm minus 70 rpm), the power generation power output by the generator 104 is increased by 47.27% (calculated from (8.1-5.5) / 5.5*100%).

[0104]

[0105] The self-powered device 100 can not include a speed-up mechanism and a speed-down mechanism. That is, in the limited space of the self-powered device 100 of the present disclosure, there is no need to configure a speed-up or speed-down mechanism, such as a sun gear, a plurality of planetary gears, etc. Therefore, it is beneficial to maintain the weight, miniaturized volume, and cost savings of the self-powered device 100.

[0106] FIG. 2A a perspective view of a self-powered device 200 of a second embodiment of the present disclosure, FIG. 2B a perspective view of FIG. 2A an exploded view of the self-powered device 200 of the second embodiment, FIG. 2C a perspective view of FIG. 2A a longitudinal sectional view of the self-powered device 200 of the second embodiment. Please refer to FIG. 2A to FIG. 2CThe self-powering device 200 is a power pedaling device for a riding device, such as a bicycle or an indoor exercise bike, and is particularly a device that can generate electricity when pedaled and rotated, that is, the self-powering device 200 is a pedaling and rotating device for a riding device. The self-powering device 200 includes a pedaling unit 210, a shaft 240, a generator 204, and an energy storage element 279. The pedaling unit 210 includes an inner surface 211 to form and surround a receiving space 215 therein, and can also be said that the pedaling unit 210 includes the inner surface 211 formed therein to form the receiving space 215. An opening of the pedaling unit 210 can be closed by an end cap 271, and the shaft 240 is received in the receiving space 215.

[0107] FIG. 2D illustrating FIG. 2C a cross-sectional view along the cross-sectional line 2D-2D, FIG. 2E illustrating FIG. 2C a cross-sectional view along the cross-sectional line 2E-2E. Please refer to FIG. 2B to FIG. 2E The generator 204 includes at least a stator 250 and a rotor 260, wherein the stator 250 is disposed on the shaft 240, the rotor 260 is disposed on a main inner surface 212 of the pedaling unit 210, the rotor 260 correspondingly surrounds the stator 250 and does not contact the stator 250, wherein the main inner surface 212 is a part of the inner surface 211 and is used to receive and mount the rotor 260. The energy storage element 279 is electrically coupled to the generator 204. When the pedaling unit 210 is rotated by a rider pedaling, the stator 250 is fixed on the shaft 240, the rotor 260 rotates with the pedaling unit 210 relative to the stator 250, the generator 204 generates power to charge the energy storage element 279.

[0108] In detail, the pedaling unit 210 further includes a pedaling main body 220 and two pedals 216 connected to the pedaling main body 220 and respectively extending along two ends of the shaft 240 in a vertical direction, and the two pedals 216 are taken as examples to form flat plate pedals. The pedaling main body 220 is essentially tubular. The inner surface 211 includes the main inner surface 212 located on an inner surface of the pedaling main body 220, and the shaft 240 includes a main portion 242 correspondingly located inside the main inner surface 212. The stator 250 of the generator 204 is disposed on the main portion 242 of the shaft 240, and the rotor 260 is disposed on the main inner surface 212 of the pedaling unit 210.

[0109] As an example but not by way of limitation, the self-powered device 200 further comprises eight sensors 278, each sensor 278 being a strain gauge and powered by an energy storage element 279. The axle core 240 comprises a body portion 242 and a base portion 243, the body portion 242 being disposed closer to the two pedals 216 of the treadle unit 210 than the base portion 243. When the bicycle comprises the self-powered device 200 as its power treadle device, the body portion 242 is located between the two bearings 272, the base portion 243 is adjacent to the crank arms of the bicycle, and the energy storage elements 279 and the sensors 278 are adjacent to the base portion 243.

[0110] Please refer to FIG. 2B and FIG. 2D , the stator 250 of the generator 204 comprises six stator teeth 257 and six stator coils 258, the six stator coils 258 being wound on the six stator teeth 257 respectively. The rotor 260 of the generator 204 comprises a rotor yoke 267 and eight rotor magnets 268, the eight rotor magnets 268 being attached or affixed on the yoke inner surface 266 of the cylindrical rotor yoke 267 in sequence, the arc length of each stator tooth 257 being less than the arc length of each rotor magnet 268, and as shown in FIG. 2D .

[0111] In particular, the generator 204 forming an alternating three-phase structure is disposed on the treadle body 220 corresponding to the body portion 242 of the axle core 240, and comprises six slots and eight poles. The stator 250 has six teeth, and the rotor 260 has eight poles.

[0112] As an example but not by way of limitation, please refer to FIG. 2B , FIG. 2C and FIG. 2E , the self-powered device 200 further comprises four circuit boards 275 and one circuit board 276, all disposed around the base portion 243. Each circuit board 275 is a printed circuit board, and the four circuit boards 275 are regularly and symmetrically arranged around the base portion 243 of the axle core 240. The circuit board 276 is a ring-shaped flexible printed circuit board to surround and be attached on the base portion 243. The circuit boards 275, 276 and the sensors 278 are all adjacent to the base portion 243, and are surrounded by the axle core shell 274 which is not connected with the treadle unit 210. The number of the sensors 278 is at least two and in particular eight, and each two of the sensors 278 form a sensor group, as shown in FIG. 2B and FIG. 2C , so that the number of the sensor groups is four. The number of the circuit boards 275 is at least two and in particular four, and the four sensor groups and the four circuit boards 275 are alternately and symmetrically arranged around the base portion 243 of the axle core 240, as shown in FIG. 2EThe energy storage element 279 is disposed in the axial receiving space surrounded by the axial inner surface 246 of the root base 243. The circuit boards 275, 276 are electrically coupled to support rectification circuit, direct current conversion circuit for the energy storage element 279 and power supply circuit for the sensor 278. The wires electrically connecting the generator 204, the circuit boards 275, 276, the energy storage element 279 and the sensor 278 are omitted in the drawing. Furthermore, the self-powered device 200 does not include speed-up mechanism and speed-down mechanism.

[0113] For the self-powered device 200 of the second embodiment, the details and parameter values of the self-powered device 100 of the first embodiment described above can be referred to and will not be repeated here.

[0114] FIG. 3A Fig. 3 shows a perspective view of a self-powered device 300 of a third embodiment of the present disclosure, FIG. 3B Fig. 4 shows an exploded view of the self-powered device 300 of the third embodiment, FIG. 3A Fig. 5 shows a longitudinal cross-sectional view of the self-powered device 300 of the third embodiment. Please refer to FIG. 3C Fig. 6 shows a longitudinal cross-sectional view of the self-powered device 300 of the third embodiment along the cross-sectional line 3D-3D, please refer to FIG. 3A Fig. 7 shows a longitudinal cross-sectional view of the self-powered device 300 of the third embodiment along the cross-sectional line 3E-3E, please refer to FIG. 3A to FIG. 3C The self-powered device 300 is a power pedal device for a riding device, such as a bicycle or an indoor exercise bike, and is particularly a device that can generate electricity when pedaled and rotated, that is, the self-powered device 300 is a pedaled and rotated device for a riding device. The self-powered device 300 includes a pedaling unit 310, an axle 340, a generator 304 and an energy storage element 379. The pedaling unit 310 includes an inner surface 311 to form and surround a receiving space 315 therein, and can also be said that the pedaling unit 310 includes the inner surface 311 formed therein to form the receiving space 315. The opening of the pedaling unit 310 can be closed by an end cap 371, and the axle 340 is received in the receiving space 315.

[0115] FIG. 3D Fig. 4 shows an exploded view of the self-powered device 300 of the third embodiment, FIG. 3C Fig. 5 shows a longitudinal cross-sectional view of the self-powered device 300 of the third embodiment. Please refer to FIG. 3B to FIG. 3D The generator 304 includes at least a stator 350 and a rotor 360, wherein the stator 350 is disposed on the axle 340, and the rotor 360 is disposed on the root inner surface 313 (i.e. a part of the inner surface 311 and used to receive and mount the rotor 360) of the pedaling unit 310, and the rotor 360 correspondingly surrounds the stator 350 and does not contact the stator 350. The energy storage element 379 is electrically coupled to the generator 304. When the pedaling unit 310 is rotated by pedaling of a rider, the stator 350 is fixed on the axle 340, the rotor 360 rotates relative to the stator 350 with the pedaling unit 310, and the generator 304 generates electricity to charge the energy storage element 379.

[0116] In detail, the pedaling unit 310 further comprises a pedaling body 320, two pedals 316 connected to the pedaling body 320 and extending along the vertical direction of the axis 340 respectively, and a pedaling base 330 connected to the pedaling body 320. The pedaling base 330 and the pedaling body 320 are essentially tubular, and the pedaling base 330 is an extended cover connected to the pedaling body 320 and can rotate with the pedaling body 320 through two bearings 372. When the bicycle comprises the self-powered device 300 as its power pedaling device, the pedaling base 330 is closer to the crank arm of the bicycle than the pedaling body 320. The inner surface 311 of the pedaling unit 310 comprises a body inner surface 312 located on the inner surface of the pedaling body 320 and a base inner surface 313 located on the inner surface of the pedaling base 330. The axis 340 comprises a body portion 342 corresponding to the body inner surface 312 and a base portion 343 corresponding to the base inner surface 313. The stator 350 is arranged on the base portion 343 of the axis 340, and the rotor 360 is arranged on the base inner surface 313. The body portion 342 is closer to the two pedals 316 of the pedaling unit 310 than the base portion 343. When the bicycle comprises the self-powered device 300 as its power pedaling device, the body portion 342 is located between the two bearings 372, and the base portion 343 is adjacent to the crank arm of the bicycle. In this way, the generator 304 is beneficial to save power consumption and obtain greater power by utilizing the inherent rotation characteristics of the self-powered device 300, without increasing the overall volume and changing the appearance of the self-powered device 300.

[0117] The self-powered device 300 can further comprise a plurality of sensors (not shown), each of which is a strain gauge and is powered by the energy storage element 379. The energy storage element 379 and the sensors can be adjacent to the base portion 343 and covered by the pedaling base 330.

[0118] FIG. 3E a perspective view of the generator 304 of the self-powered device 300 of the third embodiment, FIG. 3F a perspective view of the generator 304 of the self-powered device 300 of the third embodiment, FIG. 3E a side view of the generator 304 of the self-powered device 300 of the third embodiment, FIG. 3G a side view of the generator 304 of the self-powered device 300 of the third embodiment, FIG. 3E a parameter diagram of the generator 304 of the self-powered device 300 of the third embodiment. Please refer to FIG. 3E to FIG. 3GThe stator 350 of the generator 304 includes 12 stator teeth 357 and 12 stator coils 358, and the 12 stator coils 358 are wound on the 12 stator teeth 357, respectively. The rotor 360 of the generator 304 includes a rotor yoke 367 and 14 rotor magnets 368, and the 14 rotor magnets 368 are attached or adhered to the yoke inner surface 366 of the cylindrical rotor yoke 367 in sequence. The arc length a5 of each stator tooth 357 is less than the arc length a6 of each rotor magnet 368, and the foregoing parameters are shown in FIG. 3B. FIG. 3G

[0119] The number of the stator teeth 357 can be in a range of 3 to 18 or in a range of 10 to 14, and the number of the rotor magnets 368 can be in a range of 2 to 22 or in a range of 12 to 16. The outer diameter d4 of the generator 304 can be in a range of 20 mm to 40 mm or in a range of 27 mm to 33 mm, and the thickness t4 of the generator 304 can be in a range of 5 mm to 20 mm or in a range of 9 mm to 13 mm. The air gap g4 between the stator 350 and the rotor 360 can be in a range of 0.10 mm to 0.30 mm or in a range of 0.12 mm to 0.18 mm, and the number of turns of each stator coil 358 can be in a range of 150 turns to 400 turns or in a range of 260 turns to 290 turns. Thus, one of the key problems to be solved by the present disclosure is to overcome the difficulty of designing a suitable generator 304 in a limited space to generate sufficient electric power to charge the energy storage element 379, and the power generated by the micro-generator 304 is generally proportional to the size or volume of the generator 304 itself.

[0120] As an example but not by way of limitation, the generator 304 forming an alternating three-phase structure is disposed on the tread base shell 330 corresponding to the root portion 343 of the shaft center 340 and includes 12 slots and 14 poles. The stator 350 has 12 teeth, the rotor 360 has 14 poles, and the number of turns of each stator coil 358 is 275 turns. The magnet material of each rotor magnet 368 is neodymium iron boron (NdFeB) and its magnetic grade is N42. The arc length of each stator tooth 357 is a5, the arc length of each rotor magnet 368 is a6, the outer diameter of the generator 304 is d4, the thickness of the generator 304 is t4, the thickness of each rotor magnet 368 is t6, the air gap (length) between the stator 350 and the rotor 360 is g4, the (root) width of each stator tooth 357 is w5, the outer radius of the stator 350 is r5, the inner radius of the stator 350 is r7, and the foregoing parameters in the third embodiment are shown in FIG. 3B. FIG. 3F and FIG. 3G The values of the foregoing parameters in the third embodiment are listed in Table 4 below.

[0121]

[0122] Please refer to​FIG. 3B and FIG. 3C The self-powered device 300 further comprises a circuit board 375 disposed around the base portion 343. The circuit board 375 is a ring-shaped printed circuit board surrounding the base portion 343, and the normal direction of the surface of the circuit board 375 is parallel to the base portion 343, i.e. the surface of the circuit board 375 is perpendicular to the base portion 343. The energy storage element 379 is disposed in the central accommodating space surrounded by the central inner surface 346 of the base portion 343. The circuit board 375 supports rectification circuit for the energy storage element 379, direct current conversion circuit, and power supply circuit for sensors. The wires electrically connecting the generator 304, the circuit board 375, the energy storage element 379, and the sensors are omitted in the drawings. Furthermore, the self-powered device 300 does not comprise a speed increasing mechanism and a speed reducing mechanism. In addition, the self-powered device 300 can further comprise another circuit board, which is a flexible printed circuit board for disposing sensors or a printed circuit board, and the circuit board 375 and the another circuit board are electrically coupled.

[0123] FIG. 3H a diagram showing the output power of the generator 304 of the self-powered device 300 of the third embodiment corresponding to different pedaling frequency rates, FIG. 3I a diagram showing the rectification voltage output by the rectification circuit of the self-powered device 300 of the third embodiment corresponding to different pedaling frequency rates, and FIG. 1H The block diagram of the self-powered device 100 of the first embodiment shown in FIG. 1 can be used for the self-powered device 300 of the third embodiment. Please refer to FIG. 3H and FIG. 3I, the appropriate cadence rate of the rotor 360 can range from 60 rpm (i.e., the cadence rate is approximately transient) to 120 rpm, and the generated power output by the generator 304 can range approximately from 3.4 mW to 34.5 mW or from 5 mW to 34.5 mW. In detail, when the cadence rate of the rotor 360 ranges from 60 rpm to 80 rpm, the generated power output by the generator 304 can range from 5 mW to 11.8 mW; when the cadence rate of the rotor 360 ranges from 80 rpm to 100 rpm, the generated power output by the generator 304 can range from 11.8 mW to 21.7 mW; and when the cadence rate of the rotor 360 ranges from 100 rpm to 120 rpm, the generated power output by the generator 304 can range from 21.7 mW to 34.5 mW. A rectifier circuit can be configured between the generator 304 and the energy storage element 379, and the rectifier voltage output by the rectifier circuit can range from 0.5 VDC to 9 VDC or from 1.01 VDC to 2.6 VDC, depending on the various parameters designed for the generator 304. The DC converted voltage output by the DC conversion circuit can range from 4.15 VDC to 4.2 VDC. In this way, the generator 304 designed within the limited space of the self-powered device 300 is advantageous in generating sufficient power and appropriate voltage to effectively charge the energy storage element 379, and in turn, to power the sensors disposed therein. In addition, there can also be an external charging interface (e.g., a USB connection port) electrically coupled to the energy storage element 379 for charging the energy storage element 379 externally as a charging option.

[0124] In the third embodiment, the relationship between the transient cadence rates of 70, 80, 90, 100, 110, and 120 (rpm) and the generated power output by the generator 304 can be as shown in FIG. 3H FIG. 3H The average generated power for all the curves corresponding to the cadence rates is shown in Table 5 below, where the average generated power shown is calculated from the values at the steady state of 300 ms to 400 ms, FIG. 3H and Table 5 shows that the specific generated power at the cadence rate of 70 rpm is approximately 8.0 mW. The relationship between the transient cadence rates of 70, 80, 90, 100, 110, and 120 (rpm) and the rectifier voltage output by the rectifier circuit can be as shown in FIG. 3I FIG. 3I ​​The average rectified voltages corresponding to all curves of the tread speed are shown in Table 6 below. The average rectified voltages shown are calculated from steady-state values ​​of 300ms to 400ms. The generator 304 disclosed herein does not require a speed-up / deceleration adjustment mechanism; its various parameters only need to be appropriately designed to achieve a sufficient induced voltage level, thereby generating sufficient charging power. After the induced back electromotive force generated by the generator 304 is rectified by the rectifier circuit and boosted and regulated by the DC-DC converter circuit, a DC-DC converter voltage with an appropriate voltage level can be output from the DC-DC converter circuit and input to the energy storage element 379, thereby charging the energy storage element 379.

[0125] When the cadence of rotor 360 is between 60 rpm and 120 rpm, the power output of generator 304 increases by at least 20% for every 10 rpm increase in cadence. As an example, but not limited to this, when the cadence increases from 80 rpm to 90 rpm (i.e., an increase of 10 rpm), the power output of generator 304 increases by 38.98%. Specifically, as shown in Table 5, the power output at a cadence of 80 rpm is 11.8 mW, and the power output at a cadence of 90 rpm is 16.4 mW. Therefore, when the cadence increases by 10 rpm (calculated by subtracting 80 rpm from 90 rpm), the power output of generator 304 increases by 38.98% (calculated by (16.4 - 11.8) / 11.8 * 100%).

[0126]

[0127] FIG. 4 A schematic diagram illustrating the bicycle 40 according to the fourth embodiment of this disclosure is provided below. FIG. 4 The bicycle 40 includes a self-powered device 300 according to the third embodiment of this disclosure, wherein the self-powered device 300 is a power pedal device of the bicycle 40. Therefore, the self-powered device 300 of the actively power-supplying bicycle 40 of this disclosure includes a generator 304 for energy harvesting, thereby helping to extend the service life of the self-powered device 300.

[0128] FIG. 5 A schematic diagram illustrating the indoor exercise bike 50 according to the fifth embodiment of this disclosure is provided below. FIG. 5 The indoor exercise bike 50 includes a self-powered device 100 according to the first embodiment of this disclosure, wherein the self-powered device 100 is a power pedal device of the indoor exercise bike 50. Therefore, the self-powered device 100 of the actively power-supplying indoor exercise bike 50 of this disclosure includes a generator 104 for energy harvesting, thereby helping to extend the service life of the self-powered device 100.

[0129] While the application has been described by way of example, it should be appreciated that any modification and / or substitution of parts known to those skilled in the art can be made thereto without departing from the spirit and scope of the application as defined in the accompanying claims.

Claims

1. A self-powered device, characterized by, A self-powered device for cycling includes: a pedaling unit including an inner surface to form a receiving space therein; a shaft received in the receiving space and including a main portion and a root portion, the main portion being disposed closer to at least one pedal of the pedaling unit than the root portion; a generator including a stator disposed on the shaft and a rotor disposed on the inner surface of the pedaling unit, the rotor corresponding to surround the stator and not contacting the stator; a storage element electrically coupled to the generator and adjacent to the root portion, the storage element being disposed in a shaft receiving space surrounded by a shaft inner surface of the root portion; at least one sensor powered by the storage element and adjacent to the root portion; and at least one circuit board disposed around the root portion, wherein the at least one circuit board supports a rectification circuit for the storage element and a power supply circuit for the sensor; wherein, when the pedaling unit is rotated by a cyclist pedaling, the stator is fixed on the shaft, the rotor rotates with the pedaling unit relative to the stator, and the generator generates a power generation power to charge the storage element.

2. The self-powered device of claim 1, wherein, The stator includes a plurality of stator teeth and a plurality of stator coils, the plurality of stator coils being wound on the plurality of stator teeth, respectively; wherein the rotor includes a rotor yoke and a plurality of rotor magnets attached on a yoke inner surface of the rotor yoke in sequence, an arc length of each stator tooth being less than or equal to an arc length of each rotor magnet.

3. The self-powered device of claim 2, wherein, The pedaling unit further includes a pedaling main body, the at least one pedal being connected to the pedaling main body and extending along a vertical direction of the shaft, the pedaling main body being tubular in nature, the inner surface including a main inner surface located on an inner face of the pedaling main body, the main portion corresponding to be located within the main inner surface; wherein the stator is disposed on the main portion of the shaft, and the rotor is disposed on the main inner surface.

4. The self-powered device of claim 3, wherein the at least one of the plurality of components is a sensor. An outer diameter of the generator is in a range of 10 mm to 30 mm, and a thickness of the generator is in a range of 20 mm to 60 mm.

5. The self-powered device of claim 4, wherein the at least one of the plurality of components is a sensor. A number of the plurality of stator teeth is in a range of 3 to 12, and a number of the plurality of rotor magnets is in a range of 2 to 16.

6. The self-powered device of claim 4, wherein the at least one piezoelectric element is configured to generate the electrical power in response to a force applied to the at least one piezoelectric element. An air gap between the stator and the rotor is in a range of 0.10 mm to 0.30 mm, and a number of turns of each stator coil is in a range of 250 turns to 500 turns.

7. The self-powered device of claim 2, wherein the piezoelectric material is a piezoelectric ceramic. The pedaling unit further includes a pedaling main body and a pedaling base shell, the at least one pedal being connected to the pedaling main body and extending along a vertical direction of the shaft, the pedaling base shell being connected to the pedaling main body, the pedaling base shell and the pedaling main body being tubular in nature, the inner surface including a root inner surface located on an inner face of the pedaling base shell, the root portion corresponding to be located within the root inner surface; wherein the stator is disposed on the root portion of the shaft, and the rotor is disposed on the root inner surface.

8. The self-powered device of claim 7, wherein the at least one of the plurality of components is a sensor. An outer diameter of the generator is in a range of 20 mm to 40 mm, and a thickness of the generator is in a range of 5 mm to 20 mm.

9. The self-powered device of claim 8, wherein the at least one piezoelectric element is configured to generate the electrical power in response to a force applied to the at least one piezoelectric element. The number of the plurality of stator teeth is in a range of 3 to 18, and the number of the plurality of rotor magnets is in a range of 2 to 22.

10. The self-powered device of claim 8, wherein the at least one of the plurality of components is a sensor. An air gap between the stator and the rotor is in a range of 0.10 mm to 0.30 mm, and the number of turns of each of the stator coils is in a range of 150 turns to 400 turns.

11. The self-powered device of claim 1, wherein, When a pedaling rate of the rotor is in a range of 60 rpm to 80 rpm, the generated power output by the generator is in a range of 3.4 mW to 11.8 mW; wherein, when the pedaling rate of the rotor is in a range of 80 rpm to 100 rpm, the generated power output by the generator is in a range of 8.1 mW to 21.7 mW; wherein, when the pedaling rate of the rotor is in a range of 100 rpm to 120 rpm, the generated power output by the generator is in a range of 14.7 mW to 34.5 mW; wherein, the rectifier circuit is configured between the generator and the energy storage element, and a rectified voltage output by the rectifier circuit is in a range of 0.5 VDC to 9 VDC.

12. The self-powered device of claim 1, wherein, When a pedaling rate of the rotor is in a range of 60 rpm to 120 rpm, the generated power output by the generator increases by at least 20% for each 10 rpm increase in the pedaling rate.

13. The self-powered device of claim 1, wherein, The at least one sensor is a strain gauge, the number of the at least one sensor is at least two, the number of the at least one circuit board is at least two, and the plurality of sensors and the plurality of circuit boards are alternately and symmetrically configured around the base portion of the shaft.

14. The self-powered device of claim 1, wherein, The circuit board is a ring-shaped printed circuit board around the base portion, and a normal direction of a surface of the circuit board is parallel to the base portion.

15. The self-powered device of claim 1, wherein, The self-powered device does not include a speed increasing mechanism and a speed decreasing mechanism.

16. A bicycle characterized by Comprising: The self-powered device of any one of claims 1-15, wherein the self-powered device is a power pedal device of the bicycle.

17. An indoor exercise bike characterized in that, Comprising: The self-powered device of any one of claims 1-15, wherein the self-powered device is a power pedal device of the indoor exercise bike.

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