Patent Application
20250026440
The present disclosure relates to a power module, and more particularly to a power module of a mid-drive electric assisted bicycle.
An electric assisted bicycle, also known as an e-bike, is a bicycle with an integrated electric motor and reducer used to assist propulsion through the motor power. Many kinds of e-bikes are available in the market, while they generally fall into two categories: one is an electric assisted bicycle that detects and assists the rider's pedal-power, and another is a conventional electric bicycle that provides the motor power merely. Since related structures and circuits for manpower and motor-assisted power have to be integrated in the electric assisted bicycle at the same time, size reduction has always been an important issue in designs of a power module. In addition, the power module accepts dual power inputs (i.e., the manpower and the motor-assisted power) at the same time, in order to assist the rider's performance under different usage scenarios. Therefore, the design of the power module for the electric assisted bicycle is quite difficult.
The power module of the conventional electric assisted bicycle mainly includes a motor and a reducer, which are arranged in a housing of the power module. In the prior art, the motor and the reducer are radially arranged and sleeved around a central pedal shaft, and a fixed gear of the reducer is connected to the housing. However, the fixed gear is not easy to install onto a fixed portion of the housing, and a radial thickness of the power module is increased due to the fixed gear.
In addition, due to spatial limitations, a torque sensor of the conventional power module is disposed between an inner surface of the housing of the power module and a pedal-shaft two-way bearing, and a pedal force is transmitted through the pedal-shaft bearing. Since the torque sensor is not serially connected within a transmission path of the pedal force, an inferred pedaling torque is calculated based on a downward force from the pedal rather than an actual pedaling torque. Therefore, a sensing error is relatively large, and the pedal force of only one of two pedals can be sensed due to a position configuration of the torque sensor.
Therefore, there is a need of providing a power module with a motor and a reducer arranged axially for a mid-drive electric assisted bicycle to reduce the radial thickness and volume of the power module, improve an accuracy of pedaling torque measurement, and obviate the drawbacks encountered by the prior arts.
An object of the present disclosure is to provide a power module with the motor and the reducer arranged axially for a mid-drive electric assisted bicycle to reduce the radial thickness and volume of the power module, and improve an accuracy of pedaling torque measurement.
Another object of the present disclosure is to provide a power module of a mid-drive electric assisted bicycle. A middle frame of a housing of the power module includes a partition portion extended along a radial direction toward an inner space of the housing, and the partition portion is configured to divide the inner space of the housing into a motor accommodation portion and a reducer accommodation portion arranged along an axial direction. When the motor and the reducer are sleeved around the pedal shaft along the axial direction, a stator of the motor and a fixed gear of the reducer are fixed and connected to two opposite sides of the partition portion, so as to realize alignment and installation, improve an assembly efficiency, enhance a heat dissipation efficiency of the stator and enhance a structural robustness. Furthermore, the power of the motor is transmitted to the reducer through a reducer input shaft between the motor and the reducer the axially arranged. One end of the reducer input shaft constitutes the input-shaft rotor part connected to the rotor (the outlet shaft) of the motor or the motor output shaft, and the other end constitutes the input-shaft eccentric part connected to the movable gear of the reducer. The input-shaft main part between the input-shaft rotor part and the input-shaft eccentric part is further radially connected to the third side of the partition portion through the bearings, so that the reducer input shaft is attached to the partition portion. On the other hand, the reducer input shaft can be further extended axially and attached to the end cap of the housing. Thereby, when the motor drives the reducer to operate, the rotation axis of the reducer input shaft can run stably. In other words, the stator of the motor abuts against one side of the partition portion along the axial direction to obtain more contact area between the stator and the housing and improve the heat dissipation efficiency. The fixed gear of the reducer is axially attached to the other opposite side of the partition portion to facilitate the positioning and installation, enhance the structure, and further reduce the radial space of the power module.
A further object of the present disclosure is to provide a power module of an electric assisted bicycle. By disposing the motor and the reducer arranged along the axial direction on two opposite sides of the partition portion, compared with the radial stacking design, the volume along the axial direction is slightly increased. The slightly additional size increased can be compensated by changing the design of a bicycle frame, so that the overall volume of the power module in the present disclosure is further reduced and is suitable for mounting on the bicycle frame. By connecting the three sides of the partition portion of the housing to the fixed gear of the reducer, the motor stator and the reducer-input-shaft main part, the space utilization of the entire power module can be optimized. Therefore, there is enough space for the torque sensor to be connected to the pedal shaft, so as to realize the accurate measurement of the pedaling torque of left and right sensing. Moreover, the structure is enhanced, the rotation axis of the reducer input shaft is stable, and the heat dissipation effect of the stator is improved at the same time.
In accordance with an aspect of the present disclosure, a power module of an electric assisted bicycle is provided. The power module of the electric assisted bicycle includes a housing, a pedal shaft, a motor, a reducer, a gear-plate output shaft, a pedal-shaft two-way bearing and a sensing component. The housing defines a radial direction and an axial direction, and includes a middle frame and a partition portion, wherein the partition portion is extended along the radial direction toward an inner space of the housing, and the partition portion divides the inner space of the housing into a motor accommodation portion and a reducer accommodation portion arranged along the axial direction. The pedal shaft is accommodated in the housing and extended along the axial direction. The motor is accommodated in the motor accommodation portion and includes a stator fixed to a first side of the partition portion. The reducer is accommodated in the reducer accommodation portion, and includes a reducer input shaft, a movable gear, a fixed gear and a reducer output shaft, wherein the fixed gear is sleeved around the movable gear along the radial direction, the fixed gear is fixed to a second side of the partition portion, and the first side and the second side are opposite to each other, wherein the reducer output shaft is connected to the movable gear along the axial direction, the reducer input shaft comprises an input-shaft main part, an input-shaft rotor part and an input-shaft eccentric part, the movable gear is sleeved around the input-shaft eccentric part, the input-shaft rotor part is connected to an output shaft of the motor along the radial direction, the input-shaft main part is connected to a third side of the partition portion, and the third side is connected between the first side and the second side. The gear-plate output shaft is accommodated in the housing. The reducer output shaft is sleeved around the gear-plate output shaft through a gear-plate-output-shaft first one-way bearing, and the gear-plate output shaft is sleeved around a first end of the pedal shaft through a gear-plate-output-shaft second one-way bearing. The pedal-shaft first two-way bearing is accommodated in the housing and sleeved around a second end of the pedal shaft. The sensing component is attached to the pedal shaft and disposed adjacent to one side of the pedal-shaft first two-way bearing.
The above contents of the present disclosure will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings, in which:
The present disclosure will now be described more specifically with reference to the following embodiments. It is to be noted that the following descriptions of preferred embodiments of this disclosure are presented herein for purpose of illustration and description only. For example, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. Further, spatially relative terms, such as “right,” “left,” “inner,” “outside” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. In addition, although the “first,” “second,” “third,” and the like terms in the claims be used to describe the various elements can be appreciated, these elements should not be limited by these terms, and these elements are described in the respective embodiments are used to express the different reference numerals, these terms are only used to distinguish one element from another element. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of example embodiments. Besides, “and/or” and the like may be used herein for including any or all combinations of one or more of the associated listed items.
Notably, in the first embodiment, the motor 30 and the reducer 40 of the present disclosure are disposed and arranged along the axial direction C, and accommodated in the housing 20. Moreover, the stator of the motor 30 and the fixed gear 43 of the reducer 40 are fixed to the first side S1 and the opposite second side S2 of the partition portion 24. In the first embodiment, the housing 20 of the power module 1 includes the partition portion 24 extended along the radial direction, so that the inner space of the housing 20 is divided into two accommodation spaces arranged along the axial direction C. One is the motor accommodation portion 201 located at the left side of the partition portion 24, and another one is the reducer accommodation portion 202 located at the right side of the partition portion 24. The stator 31 of the motor 30 is disposed adjacent to the first side S1 (the left side) of the partition portion 24, the fixed gear 43 (or called as the inner ring gear) of the reducer 40 is disposed adjacent to the second side S2 (the right side) of the partition portion 24, and the input-shaft main part 411 between the motor 30 and the reducer 40 is disposed adjacent to the third side S3 (the inner side) of the partition portion 24. The partition portion 24 is a partial extension of the middle frame 22 of the housing 20, on which the reducer and the motor components can rely to be fixed to the housing 20. Furthermore, one end (the left end) of the reducer input shaft 41 acts as the input-shaft rotor part 412, and the other end (the right end) of the reducer input shaft 41 acts as the input-shaft eccentric part 413. In the first embodiment, a terminal surface of the input-shaft rotor part 412 is connected to the rotor output shaft of the motor 30 and an encoder rotating part 61. An input-shaft-main-part first two-way bearing 82 and an input-shaft-main-part second two-way bearing 83 are disposed between the input-shaft main part 411 and the third side S3 of the partition portion 24. In detail, the inner sides of the input-shaft-main-part first two-way bearing 82 and the input-shaft-main-part second two-way bearing 83 are disposed adjacent to the input-shaft main part 411, and other outer sides of the input-shaft-main-part first two-way bearing 82 and the input-shaft-main-part second two-way bearing 83 are disposed adjacent to the third side S3 (the inner side) of the partition portion 24, so as to fix the input-shaft main body 411. As a result, the reducer 40 can rotate stably around an axis during operation. Moreover, the fixed gear 43 of the reducer 40 is disposed adjacent to the second side S2 of the partition portion 24 along the axial direction C, which results a smaller radial space of the power module 1 compared with that of the conventional implementation having a fixed gear radially connected to the housing. The stator 31 of the motor 30 is attached to the inner surface of the middle frame 22 and the first side S1 of the partition portion 24, to be held firmly and increase a contact area with the housing to improve a heat dissipation efficiency. By disposing the stator 31 of the motor 30, the fixed gear 43 of the reducer 40 and the reducer-input-shaft main part 411 of the reducer 40 adjacent to the three sides S1, S2, S3 of the partition portion 24 of the housing 20, the inner space of the housing 20 of the entire power module 1 can be fully used and optimized. Therefore, there is enough space for the sensing component 60 such as the torque sensor to be disposed on the surface of the pedal shaft 10. Moreover, the structural robustness of the power module 1 is enhanced, the rotation axis of the reducer input shaft 41 is stable, and the heat dissipation efficiency of the stator is improved at the same time.
In the first embodiment, the power module 1 further includes a chain sprocket 51 coaxially sleeved around the gear-plate output shaft 50, and the chain sprocket 51 is configured to transmit an assisted torque output of the gear-plate output shaft 50, or transmit a torque output provided by a forward rotation from human pedaling. Preferably but not exclusively, the torque output is transmitted to a rear wheel (not shown) through a chain of the electric assisted bicycle, so that the electric assisted bicycle goes forward. Notably, the torque output is provided through the gear-plate output shaft 50 or the chain sprocket 51. Preferably but not exclusively, in an embodiment, the torque output is provided by the human-pedaling power. In another embodiment, the torque output is provided by the motor 30 driving the reducer 40 to rotate the gear-plate output shaft 50. In other embodiments, the torque output is provided by both of the human-pedaling power and the motor assisted power. Certainly, the gear-plate output shaft 50 and the chain sprocket 51 of the present disclosure can be disposed close to a right foot side or left foot side of the rider, so as to drive the chain and the rear wheel to rotate and make the electric power-assisted bicycle move forward.
In the first embodiment, the power module 1 include an input-shaft-main-part first two-way bearing 82 and an input-shaft-main-part second two-way bearing 83 arranged along the axial direction C. In addition, the input-shaft-main-part first two-way bearing 82 and the input-shaft-main-part second two-way bearing 83 are sleeved around the input-shaft main part 411 and disposed adjacent to the third side S3 of the partition portion 24, respectively. The input-shaft-main-part second two-way bearing 83 is connected to one end (the right end) of the input-shaft rotor part 412 along the axial direction C. Moreover, in the first embodiment, the power module 1 includes an input-shaft-eccentric-part first two-way bearing 84, which is sleeved around the input-shaft eccentric part 413 and disposed adjacent to the movable gear 42. The power module 1 further includes a gear-plate-output-shaft first two-way bearing 85 and a gear-plate-output-shaft second two-way bearing 86. The gear-plate-output-shaft first two-way bearing 85 is sleeved around the gear-plate output shaft 50 and disposed adjacent to the right cap 23 of the housing 20 in the radial direction, and disposed adjacent to the gear-plate-output-shaft first one-way bearing 87 along the axial direction C. The gear-plate-output-shaft second two-way bearing 86 is sleeved around the gear-plate output shaft 50 and the pedal shaft 10, and disposed adjacent to the gear-plate-output-shaft second one-way bearing 88 along the axial direction C. In the first embodiment, the gear-plate-output-shaft first two-way bearing 85 and the gear-plate-output-shaft second two-way bearing 86 are configured for restricting the gear-plate output shaft 50 from moving along the axial direction C. In the first embodiment, the power module 1 further includes a reducer-output-shaft first two-way bearing 89, which is sleeved and connected between the reducer output shaft 44 and the inner surface of the housing 20. In the embodiment, the inner surface of the housing 20 is located at the right cap 23.
In the first embodiment, the stator 31 of the motor 30, the fixed gear 43 of the reducer 40 and the reducer-input-shaft main part 411 of the reducer 40 are disposed adjacent to the three sides S1, S2, S3 of the partition portion 24 of the housing 20, respectively, so that the inner space of the housing 20 of the entire power module 1 can be fully used and optimized. Therefore, there is enough space for the sensing component 60 to be accommodated in the housing 20 and connected to the surface of the pedal shaft 10.
Referring to
Notably, when the motor and the reducer are radially disposed and arranged according to the prior art, although a width along the axial direction C is reduced, the radial thickness is relatively increased. In contrast, in the present disclosure, the motor 30 and the reducer 40 are arranged along the axial direction C, the volume along the axial direction C is slightly increased compared with the radial stacking design. However, a bicycle frame can be modified appropriately to compensate the slightly increased volume, so that the overall volume of the power module 1 is further reduced and is suitable for mounting on the bicycle frame, while an aesthetic appearance is provided.
On the other hand, in order to meet requirements of volume miniaturization and balance of bilateral (pedaling) sensing, the sensor component 60 such as the torque sensor is arranged in a middle of the pedal shaft 10. Preferably but not exclusively, the sensing component 60 is disposed at the right side of the pedal-shaft first two-way bearing 81 but not in contact with the pedal-shaft first two-way bearing 81, and is connected to the pedal shaft 10. Therefore, based on this design, the reducer 40 is moved (towards the right side indicated in the figure) along the axial direction C to give way to radial space for sensing component 60, so that an axial arrangement of the reductor 40 and the motor 30 is formed. Compared with the conventional radial stacking design of the motor and the reducer, the present disclosure is able to reduce a part of the radial space of the original design after the reducer 40 is moved along the axial direction C, and allow the sensing component 60 (the torque sensor) to be disposed in the middle of the pedal shaft 10. Since the sensing component 60 is connected to the surface of the pedal shaft 10 and is placed in the middle, it is connected in series in the torque flow (transmission) path, so that the requirement for bilateral (pedaling) sensing balance is realized.
In the first embodiment, when a right pedaling torque is inputted to the pedal shaft 10 by the rider, as shown in
In the first embodiment, when a left pedaling torque is inputted to the pedal shaft 10 by the rider, as shown in
In summary, the present disclosure provides a mid-drive power module with the motor and the reducer arranged axially for an electric assisted bicycle to reduce the radial thickness and volume of the power module, and improve the accuracy of pedaling torque measurement. The middle frame of the housing includes a partition portion extended along the radial direction toward the inner space and divides an inner space of the housing into a motor accommodation portion and a reducer accommodation portion arranged along the axial direction. When the motor and the reducer are sleeved around the pedal shaft along the axial direction, the stator of the motor and the fixed gear of the reducer are fixed and connected to the two opposite sides of the partition portion, so as to realize the alignment and installation, improve the assembly efficiency, enhance the heat dissipation efficiency of the stator and enhance the structure. Furthermore, the power of the motor is transmitted to the reducer through a reducer input shaft between the motor and the reducer that are axially arranged. One end of the reducer input shaft constitutes the input-shaft rotor part connected to the rotor (the outlet shaft) of the motor or the motor output shaft, and the other end constitutes the input-shaft eccentric part connected to the movable gear of the reducer. The input-shaft main part between the input-shaft rotor part and the input-shaft eccentric part is further radially connected to the third side of the partition portion through the bearings, so that the reducer input shaft is attached to the partition portion. On the other hand, the reducer input shaft can be further extended along the axial direction and attached to the end cap of the housing. Thereby, when the motor drives the reducer to operate, the rotation axis of the reducer input shaft can run stably. In other words, the stator of the motor abuts against one side of the partition portion along the axial direction to obtain more contact area between the stator and the housing and improve the heat dissipation efficiency. The fixed gear of the reducer is axially attached to the other opposite side of the partition portion to facilitate the positioning and installation, enhance the structure, and further reduce the radial space of the power module. By disposing the motor and the reducer arranged along the axial direction on two opposite sides of the partition portion, compared with the radial stacking design, the volume along the axial direction is slightly increased. The slightly additional size increased can be compensated by changing the design of the bicycle frame, so that the overall volume of the power module in the present disclosure is further reduced and is suitable for mounting on the bicycle frame. By connecting the three sides of the partition portion of the housing to the fixed gear of the reducer, the motor stator and the reducer-input-shaft main part, the space utilization of the entire power module can be optimized. Therefore, there is enough space for the torque sensor to be connected to the pedal shaft, so as to realize the accurate measurement of the pedaling torque of left and right sensing. Moreover, the structure is enhanced, the rotation axis of the reducer input shaft is stable, and the heat dissipation effect of the stator is improved at the same time.
While the disclosure has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202311178903.4 | Sep 2023 | CN | national |
This application claims the benefit of U.S. Provisional Application No. 63/527,246 filed on Jul. 17, 2023, and entitled “E-BIKE POWER MODULE”. This application also claims priority to China Patent Application No. 202311178903.4, filed on Sep. 13, 2023. The entireties of the above-mentioned patent application are incorporated herein by reference for all purposes.
| Number | Date | Country | |
|---|---|---|---|
| 63527246 | Jul 2023 | US |
