Stable high-power plug-in middle-position motor

Abstract

This invention provides a stable, high-power plug-in mid-drive motor, comprising a main housing, an axle sleeve for insertion into a bicycle bottom bracket assembly, and an assembly shell fixed to the upper part of the axle sleeve. An electric module is mounted on the left side of the assembly shell. A through hole is machined in the center of the assembly shell, through which the output shaft of the electric module extends from the left side to the right side of the assembly shell. A mounting bracket is fixedly mounted on the right side of the assembly shell. Two or more planetary shafts, circumferentially distributed relative to the output shaft, are mounted between the assembly shell and the mounting bracket. Planetary gears are mounted on the planetary shafts, and a sun gear for meshing transmission is mounted outside the planetary gears. A transition module is connected to the sun gear for transmission, and the transition module is connected to the chainring drive. This motor employs a planetary transmission structure internally, resulting in more stable transmission and significantly increasing the motor's output power within the same volume.

Description

Technical Field

[0001] This invention belongs to the field of motor technology, specifically relating to a stable high-power plug-in mid-drive motor. Background Technology

[0002] Electric bicycles are generally divided into hub motors and mid-drive motors. Mid-drive motors can be further divided into plug-in mid-drive motors and integrated mid-drive motors. Plug-in mid-drive motors typically use a two-stage transmission structure to connect the motor's output shaft and sprocket, simultaneously achieving a speed reduction function. For example, patent CN2541317Y discloses a dual-purpose actuator for electric bicycles, and patent CN2561697Y discloses an electric auxiliary transmission for bicycles; both use this structure. This motor structure can be directly plugged into the bicycle's bottom bracket, greatly facilitating direct modification and installation on ordinary bicycles, giving traditional bicycles auxiliary power and making them easier for riders to use.

[0003] However, this type of transmission structure typically uses a single gear set for direct meshing and speed reduction. This structure results in a relatively low transmission speed. The use of single-tooth meshing means all power is transmitted directly between two independent gears, leading to uneven force distribution and potential vibration. This affects the overall smoothness of the motor transmission. Furthermore, the two independent gears experience greater stress, especially during direct power output, causing intense friction and wear on the gears directly meshing with the electric module. Gears with smaller modules and fewer teeth experience particularly severe wear. Moreover, this traditional plug-in mid-drive motor structure has a low speed reduction ratio for its gear module design within the same volume. Therefore, traditional plug-in mid-drive motors are typically designed with lower power and shorter lifespans. Especially under severe impacts, these motors not only fail to provide sufficient auxiliary power but also significantly exacerbate motor damage. To minimize the impact on the bicycle's portability, this type of plug-in motor needs a compact structure and a small size.

[0004] In summary, these factors result in traditional plug-in mid-drive motors having lower power, greater vibration, and shorter lifespan. This significantly limits the assist capabilities of electric bicycles using mid-drive motors, leading to a poor riding experience when using this motor as auxiliary power. For example, electric bicycles using traditional plug-in mid-drive motors typically have lower power, making it unable to provide rapid assist or sufficient assistance on inclines or mountainous terrain.

[0005] In addition, traditional plug-in mid-drive motors typically use a cantilever structure for the transmission gear when transmitting power between the motor output shaft and the bicycle's mid-drive axle. This makes the overall transmission process less stable, which can also affect the motor's lifespan. Summary of the Invention

[0006] To address the above problems, this invention provides a stable, high-power plug-in mid-drive motor with a compact structure and a planetary transmission structure inside the motor, which can significantly increase the motor's output power within the same volume, enabling the motor to provide more powerful performance for modified bicycles.

[0007] The technical solution adopted by this invention to solve its technical problem is as follows: The stable high-power plug-in mid-drive motor includes a main housing, the main housing includes a bushing for insertion into the bottom bracket assembly of a bicycle, and an assembly shell fixed to the upper part of the bushing. A bottom bracket is assembled inside the bushing, and a pedal rod is assembled on the bottom bracket. An electric module is assembled on the left side of the assembly shell. A through hole is machined in the middle of the assembly shell. The output shaft of the electric module extends from the left side to the right side of the assembly shell. A fixing frame is fixedly assembled on the right side of the assembly shell. Two or more planetary shafts are evenly distributed circumferentially relative to the output shaft between the assembly shell and the fixing frame. Each planetary shaft is equipped with a planetary gear that meshes with the gear on the output shaft. A sun gear that meshes with the planetary gear is assembled outside the planetary gear. A transition module is connected to the sun gear for transmission. The transition module is connected to the chainring for transmission.

[0008] Preferably, the sun gear is designed with two coaxial external gears and internal gears of different diameters. The internal gear on the sun gear meshes with the external gear of the planetary gear. The diameter of the internal gear on the sun gear is larger than that of the external gear. The external gear on the sun gear meshes with the transition module for transmission.

[0009] Preferably, the planetary gear has two coaxial external gears of different diameters machined on it. The larger diameter external gear on the planetary gear meshes with the gear on the output shaft, and the smaller diameter external gear on the planetary gear meshes with the internal gear of the sun gear.

[0010] Preferably, the assembly housing and the fixing frame are designed with three planetary shafts evenly distributed around the axis.

[0011] Preferably, the transition module includes a transition gear shaft with an integral external gear machined on it. The transition gear shaft is mounted on the assembly housing via a rotating component, and an external gear that meshes with the sun gear is fixedly mounted on the transition gear shaft.

[0012] Preferably, the transition module is connected to the crankset via a resultant bearing. The resultant bearing includes an annular, coaxially assembled inner sleeve, outer sleeve, and middle sleeve. Rolling elements are assembled between the inner sleeve, outer sleeve, and middle sleeve, respectively. The inner wall of the inner sleeve, the outer wall of the outer sleeve, and the end of the middle sleeve are designed with assembly structures. A clutch is assembled between the inner sleeve or outer sleeve and the middle sleeve. The clutch and the annular sleeve assembling the clutch form a one-way transmission structure. The crankset is assembled on the middle sleeve, and the inner sleeve is fixedly assembled with the central shaft.

[0013] Preferably, an external gear is integrally machined on the outer sleeve of the combined bearing, and the external gear on the outer sleeve is connected to the transition module for transmission.

[0014] Preferably, a right shell is fixedly mounted on the right side of the assembly shell, the left side of the right shell is fixedly mounted to the fixing frame, the right side of the transition gear shaft is connected to the right shell via a rotating component, and the right shell is fixed to the main shell by a pin.

[0015] Preferably, magnetic encoders are installed inside the main housing and the right housing.

[0016] Preferably, a left shell enclosing the electric module is fitted on the right side of the main housing, and a controller sealed with adhesive is fitted inside the lower part of the left shell.

[0017] Preferably, the transition module is connected to the chainring via an auxiliary gear. The auxiliary gear is integrally machined and coaxially mounted on the central shaft. The chainring is fixed to the right side of the auxiliary gear. The auxiliary gear is designed with a stepped structure and has a shoulder structure machined on its exterior. The inner wall and outer shoulder of the auxiliary gear are respectively assembled via rotating parts.

[0018] The beneficial effects of this invention are as follows: This stable, high-power plug-in mid-drive motor is mainly used in the bottom bracket position of bicycles, and can directly replace the original bottom bracket parts. The motor provides auxiliary power to the rider by driving the chainring through an electric module. The motor's planetary transmission structure is assembled through the cooperation of the main housing's mounting shell and the fixing frame, and the sun gear in the planetary transmission structure further transmits power downwards. This allows the entire transmission structure to be compactly assembled within the housing. In traditional plug-in mid-drive motors, the corresponding transmission part of this planetary transmission structure directly receives the output transmission from the electric module, providing power to the entire electric module. The main wear and load-bearing parts are controlled by a planetary structure, which uses multiple planetary gears for simultaneous transmission. This allows each planetary gear to effectively distribute the power output of the electric module. Furthermore, because the force is evenly distributed circumferentially from the planetary gears to the annular sun gear, the transmission is more stable with less vibration, and the sun gear outputs greater power. Additionally, the planetary transmission structure allows for a higher transmission ratio from the electric module to the final auxiliary output section of the chainring, enabling the motor to handle higher power. This allows the motor to provide higher power output during use, and also allows for a wider range of material choices for the planetary gears, resulting in lower wear.

[0019] In this motor, the planetary transmission structure and the electric module are mounted on both sides of the main housing, resulting in a more reasonable overall layout. This effectively reduces motor vibration, decreases wear on the transmission parts, and extends motor life, making the ride more comfortable for riders. At the same time, the motor's higher power design can provide higher power output when needed, allowing the bicycle to be used in more situations, such as climbing steeper slopes and providing higher automatic travel speeds when required. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the cross-sectional structure of the stable high-power plug-in mid-drive motor in Example 1.

[0021] Figure 2 This is a perspective view of the internal transmission structure of the stable high-power plug-in mid-drive motor in Example 1.

[0022] Figure 3 This is a structural schematic diagram of the sun gear in cross-sectional direction.

[0023] Figure 4 This is a structural schematic diagram of the planetary gear in cross-sectional direction.

[0024] Figure 5 This is a schematic diagram of the cross-sectional structure of the stable high-power plug-in mid-drive motor in Example 2. Detailed Implementation

[0025] The present invention will be further described below with reference to embodiments:

[0026] The directional terms and positional relationships used in this patent are based on the orientation or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0027] In Example 1

[0028] like Figure 1 and Figure 2 As shown in Embodiment 1, the stable high-power plug-in mid-drive motor includes a main housing 1. The main housing 1 includes a bushing 11 for insertion into the bottom bracket assembly of a bicycle, and an assembly shell 12 fixed to the upper part of the bushing 11. A bottom bracket 2 is assembled inside the bushing 11, and a pedal rod 3 is assembled on the bottom bracket 2. The pedal rod 3 is used to provide pedaling force through a foot pedal. An electric module 4 is assembled on the left side of the assembly shell 12. In this embodiment, the structure of the bushing 11 is similar to the conventional structure and will not be described in detail again. The electric module 4 also adopts a commonly used electromagnetic power structure. Specifically, in this embodiment, an internal rotor transmission structure is used to output power.

[0029] In this patent, the assembly housing 12 has a through hole in the middle. The output shaft 41 of the electric module 4 extends from the left side of the assembly housing 12 through the through hole to the right side. A fixing bracket 5 is fixedly mounted on the right side of the assembly housing 12. Three planetary shafts 51 are evenly distributed circumferentially relative to the output shaft 41 between the assembly housing 12 and the fixing bracket 5. Each planetary shaft 51 is equipped with a planetary gear 52 that meshes with the fixed gear on the output shaft 41. In this embodiment, the output shaft 41 and the gear on it are integrally machined, that is, the output shaft 41 and the gear on it constitute a gear shaft. A sun gear 53 for meshing transmission is mounted on the outside of the planetary gear 52. A transition module 6 is drivenly connected to the sun gear 53, and the transition module 6 is drivenly connected to the chainring 3.

[0030] This stable, high-power plug-in mid-drive motor is mainly used in the bottom bracket position of bicycles. It can directly replace the original bottom bracket parts of bicycles. The motor drives the chainring 3 to move through the electric module, providing auxiliary power for riders. The motor is assembled with a planetary transmission structure through the cooperation of the mounting shell 12 of the main housing 1 and the fixing frame 5. The power is further transmitted downward by the sun gear 53 in the planetary transmission structure, so that the entire transmission structure is compactly assembled in the housing. In traditional plug-in mid-drive motors, the transmission part corresponding to the planetary gear structure directly receives the output transmission of the electric module 4, and is the main wear and load-bearing part of the entire electric module. However, in this embodiment, due to the use of the planetary structure, three planetary gears 52 are used for simultaneous transmission, so that each planetary gear 52 can effectively distribute the power output of the electric module 4. At the same time, since the force is evenly output to the annular sun gear 53 through the planetary gears 52, the transmission is more stable and the vibration is smaller. The power output of the sun gear 53 is also greater. In addition, the use of the planetary gear structure allows for a higher transmission ratio from the electric module 4 to the final auxiliary output part of the chainring 3, so that the motor as a whole can be used for higher power. While keeping the overall motor compact, this motor structure can greatly increase its power output. At the same time, since multiple planetary gears 52 are used for force transmission, the material selection is wider and the wear is lower.

[0031] In this motor, the planetary transmission structure and the electric module 4 are mounted on both sides of the mounting shell 12 on the main housing. This more rational overall layout effectively reduces motor vibration, minimizes wear on the transmission components, and extends motor lifespan, resulting in greater rider comfort. The higher power design allows for greater power output when needed, making the bicycle suitable for more diverse riding situations, such as climbing steeper slopes and achieving higher automatic speeds. Furthermore, the planetary transmission structure allows for a larger gear ratio within the same space, further improving the motor's design performance and significantly enhancing its usability.

[0032] In specific implementation, such as Figure 1 , Figure 2 and Figure 3As shown, the sun gear 53 is designed with two coaxial external gears and internal gears of different diameters. The internal gear on the sun gear 53 meshes with the external gear on the planet gear 52. The diameter of the internal gear on the sun gear 53 is larger than that of the external gear. The external gear on the sun gear 53 meshes with the transition module 6 for transmission. The design of the large internal gear on the sun gear 53 means that the two gears on the sun gear 53 are not on the same plane perpendicular to the axis, making it a stepped gear. This stepped structure design makes this improved structure more compatible with the original mid-mounted motor structure, and at the same time, it achieves speed reduction transmission. In addition, in this structure, the rotary bearing is directly mounted on the inner side of the external gear ring of the sun gear 53, resulting in more reasonable force distribution.

[0033] like Figure 1 , Figure 2 and Figure 4 As shown, the planetary gear 52 has two coaxial external gears of different diameters machined on it. The larger diameter external gear on the planetary gear 52 meshes with the gear on the output shaft 41, and the smaller diameter external gear on the planetary gear 52 meshes with the internal teeth of the sun gear 53. Since the sun gear 53 is enclosed by the planetary gear 52, this stepped structure design effectively reduces the size of the sun gear. Simultaneously, the stepped structure design of the large and small external teeth on the planetary gear 52 further reduces the speed of the motor, effectively increasing the reduction ratio. This combination of multiple planetary gears 52 in the planetary transmission allows for a large reduction ratio within a limited space while ensuring the overall transmission stability of the motor.

[0034] like Figure 1 As shown, the transition module 6 includes a transition gear shaft 61, on which an integral external gear is machined. The transition gear shaft 62 is mounted on the assembly housing 12 via a rotating component. The external gear 62 that meshes and drives the sun gear 53 is fixedly mounted on the transition gear shaft 61.

[0035] like Figure 1 and Figure 2As shown, the transition module 6 is connected to the crankset 7 via a force bearing 8. The force bearing 8 includes an annular, coaxially assembled inner sleeve 81, outer sleeve 82, and middle sleeve 83. Rolling elements 84 are assembled between the inner sleeve 81, outer sleeve 82, and middle sleeve 83, respectively. The inner wall of the inner sleeve 81, the outer wall of the outer sleeve 82, and the end of the middle sleeve 83 are designed with assembly structures. A clutch is assembled between the inner sleeve or outer sleeve and the middle sleeve 83. The clutch and the annular sleeve assembling the clutch form a one-way transmission structure. The crankset 7 is mounted on the middle sleeve 83, and the inner sleeve 81 is fixedly assembled with the central shaft. In this embodiment, an external gear is integrally machined on the outer sleeve 82 of the force bearing 8, and the external gear on the outer sleeve 82 meshes with the external gear 62 on the transition module 6 for transmission. When the motor is used to assist a bicycle, the power from the electric module 4 is transmitted through the planetary transmission structure and the transition module 6 to the outer sleeve 82 of the resultant bearing 8. The outer sleeve then transmits the power unidirectionally to the chainring 7, thus achieving electric drive for the modified bicycle. When the modified bicycle is pedaled, the pedaling force is transmitted through the bottom bracket 2 to the inner sleeve 81, which then transmits the pedaling force unidirectionally to the chainring on the middle sleeve 83. This achieves the combined output of electric power and pedaling force. When the pedaling force and the power force are transmitted to the chainring 7 through the resultant bearing 8, both are unidirectional drives, ensuring that the motor, pedaling force, and electric power do not directly affect each other. When the electric module 4 moves quickly, the inner sleeve 81 connecting the bottom bracket 2 and the pedal directly disengages, achieving full electric drive. When the pedaling speed is faster than the electric module 4, the transition module 6, the outer sleeve 82, and the chainring connected to the middle sleeve 83 disengage, achieving independent pedal drive. The use of the aforementioned combined bearing greatly simplifies the entire transmission structure, eliminating the need for a separate clutch structure. This significantly reduces the number of parts and makes assembly more convenient.

[0036] like Figure 1 As shown, a right shell 13 is fixedly mounted on the right side of the assembly housing, and the left side of the right shell is fixedly mounted to the fixing frame 5. The right side of the transition gear shaft 61 is connected to the right shell 13 via a rotating component. The right shell 13 is fixed to the main housing 1 by a pin. After the right shell 13 and the main housing 1 are connected by the pin, they are fixed as one unit. In this way, the transition gear shaft 61 is assembled on both sides via rotating components. Compared with the traditional cantilever structure, the transition gear shaft 61 in this motor moves more stably, has a longer service life, and has a better transmission effect.

[0037] like Figure 1 As shown, a magnetic encoder 9 is installed inside the main housing 1 and the right housing 13. Specifically, the magnetic encoder 9 is a rotary magnetic encoder, which can be used to measure the change in the output magnetic force of the electric module 4, thereby determining the overall operating status of the motor.

[0038] like Figure 1 As shown, the right side of the main housing 1 is fitted with a left housing 14 that encloses the electric module 4. Inside the left housing 14, near the bottom, is a sealed controller 10. Specifically, the left housing 14 has a dedicated mounting cavity at the bottom where the electric module 4 is mounted, and the controller 10 is installed inside. This allows the entire circuit structure to be assembled inside the housing, resulting in a more aesthetically pleasing design. Furthermore, the circuit board of the controller 10 is sealed with adhesive, providing better waterproofing and ensuring the overall stability of the circuit board during use. Even if the motor is exposed to rain during use, it will not cause a short circuit and pose a danger.

[0039] Example 2

[0040] like Figure 5 As shown, most of the structure of Embodiment 2 is the same as that of Embodiment 1. In Embodiment 2, the transition module 6 is connected to the crankset 7 via an auxiliary gear 8a. Specifically, the two are directly fixed together using bolts. The auxiliary gear 8a is designed with a stepped structure, and the auxiliary gear 8a has a shoulder structure machined on its exterior. The inner wall and the outer shoulder of the auxiliary gear 8a are respectively assembled using rotating parts. This assembly design of the auxiliary gear 8a makes the transmission of the auxiliary gear 8a more stable. In this embodiment, the auxiliary gear is machined as a single piece, and the auxiliary gear 8a is coaxially assembled on the central shaft. The crankset is directly fixed to the right side of the auxiliary gear 8a. In this way, the auxiliary gear 8a is directly connected to the crankset 7, and the double rotation limit assembly of the auxiliary gear 8a makes the crankset 7 more stable when it follows the movement of the auxiliary gear 8a.

[0041] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A stable, high-power plug-in mid-drive motor, comprising a main housing, the main housing including a bushing for insertion into a bicycle bottom bracket assembly, and an assembly shell fixed to the upper part of the bushing, a bottom bracket being assembled inside the bushing, a pedal rod being assembled on the bottom bracket, and an electric module being assembled on the left side of the assembly shell; characterized in that: The assembly housing has a through hole in the middle. The output shaft of the electric module extends from the left side to the right side of the assembly housing. A fixing bracket is fixedly mounted on the right side of the assembly housing. Two or more planetary shafts are evenly distributed circumferentially relative to the output shaft between the assembly housing and the fixing bracket. Each planetary shaft is equipped with a planetary gear that meshes with the gear on the output shaft. A sun gear that meshes with the planetary gear is mounted on the outside of the planetary gear. A transition module is connected to the sun gear and is connected to the chainring drive.

2. The stable high-power plug-in mid-drive motor according to claim 1, characterized in that: The sun gear is designed with two coaxial external gears and internal gears of different diameters. The internal gear on the sun gear meshes with the external gear of the planetary gear. The diameter of the internal gear on the sun gear is larger than that of the external gear. The external gear on the sun gear meshes with the transition module for transmission.

3. The stable high-power plug-in mid-drive motor according to claim 2, characterized in that: The planetary gear has two coaxial external gears of different diameters. The larger diameter external gear on the planetary gear meshes with the gear on the output shaft, and the smaller diameter external gear on the planetary gear meshes with the internal gear of the sun gear.

4. The stable high-power plug-in mid-drive motor according to any one of claims 1-3, characterized in that: The assembly housing and the fixing frame are designed with three planetary shafts evenly distributed around the axis.

5. The stable high-power plug-in mid-drive motor according to any one of claims 1-3, characterized in that: The transition module includes a transition gear shaft with an integral external gear machined on it. The transition gear shaft is mounted on the assembly housing via a rotating component, and an external gear that meshes with and drives the sun gear is fixedly mounted on the transition gear shaft.

6. The stable high-power plug-in mid-drive motor according to any one of claims 1-3, characterized in that: The transition module is connected to the crankset via a resultant bearing. The resultant bearing includes an annular coaxially assembled inner sleeve, outer sleeve, and middle sleeve. Rolling elements are assembled between the inner sleeve, outer sleeve, and middle sleeve. The inner wall of the inner sleeve, the outer wall of the outer sleeve, and the end of the middle sleeve are designed with assembly structures. A clutch is assembled between the inner sleeve or outer sleeve and the middle sleeve. The clutch and the annular sleeve assembling the clutch form a one-way transmission structure. The crankset is assembled on the middle sleeve, and the inner sleeve is fixedly assembled with the central shaft.

7. The stable high-power plug-in mid-drive motor according to claim 6, characterized in that: An external gear is integrally machined on the outer sleeve of the combined bearing, and the external gear on the outer sleeve is connected to the transition module for transmission.

8. The stable high-power plug-in mid-drive motor according to claim 5, characterized in that: The right side of the assembly housing is fixedly assembled with a right shell, the left side of the right shell is fixedly assembled with the fixing frame, the right side of the transition gear shaft is assembled and connected to the right shell through a rotating part, and the right shell is fixed to the main housing by a pin.

9. The stable high-power plug-in mid-drive motor according to any one of claims 1-3, characterized in that: The main housing and the right housing are equipped with magnetic encoders; the right side of the main housing is equipped with a left housing that encloses the electric module, and the lower part of the left housing is equipped with a controller sealed with glue.

10. The stable high-power plug-in mid-drive motor according to any one of claims 1-3, characterized in that: The transition module is connected to the chainring via an auxiliary gear. The auxiliary gear is integrally machined and coaxially mounted on the central shaft. The chainring is fixed to the right side of the auxiliary gear. The auxiliary gear is designed with a stepped structure and has a shoulder structure machined on its exterior. The inner wall and outer shoulder of the auxiliary gear are respectively assembled via rotating parts.

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