Middle motor of urban power-assisted bicycle

Abstract

The utility model discloses a middle motor of an urban power-assisted bicycle, which comprises a shell composed of a first half shell and a second half shell. A motor assembly, a speed reduction transmission assembly, a data acquisition assembly, a control module, a torque output sleeve and a manpower input shaft are installed in the shell. The first half shell is internally provided with a first cavity for accommodating a stator and a rotor, and is also provided with a second cavity for accommodating a data acquisition assembly; a third cavity for accommodating the speed reduction transmission assembly is formed in the second half shell; a fixed cover plate positioned at the opening part of the first cavity is fixed in the shell, and first bearings for supporting a middle shaft of the motor assembly are respectively mounted at the bottom of the fixed cover plate and the bottom of the first cavity; the second half shell and the fixed cover plate are respectively provided with a second bearing for supporting the transition shaft; and the control module comprises a main control board fixed on the fixed cover plate. The built-in motor has the advantages of reasonable and compact structural layout and small size.

Description

Technical Field

[0001] The utility model relates to the technical field of motors, in particular to a mid-mounted motor for a city power-assisted bicycle. Background Art

[0002] As a core component of electric-assisted bicycles (E-Bikes), the development and technological innovation of mid-mounted motors are closely linked to the progress and transformation of the entire E-Bike industry. In particular, the pursuit of higher energy efficiency, a better riding experience, and intelligent control has significantly advanced the design and manufacturing technology of mid-mounted motors. Since the 2010s, with growing environmental awareness and the demand for diversified urban transportation solutions, the E-Bike market has experienced explosive growth. Mid-mounted motors, mounted directly on the bicycle's bottom bracket, can more effectively utilize the rider's pedaling force for assistance, resulting in a more natural riding experience and higher energy conversion efficiency, making them a focus of industry attention. Against this backdrop, major manufacturers have invested heavily in research and development, with patent applications covering a wide range of areas, from torque sensing technology and transmission efficiency optimization to clutch mechanisms and vibration damping design. The goal is to create more efficient, durable, and user-friendly mid-mounted motor systems that meet the performance and quality expectations of diverse consumers for E-Bikes, driving technological innovation and market expansion across the industry.

[0003] In the prior art, the mid-mounted motor of patent CN115042908A includes a motor part, a reduction gear set, a human input shaft and an output sleeve. The seat body design of the mid-mounted motor is relatively complex, including an intermediate seat body and a protective cover composed of multiple parts. The integrity is poor, resulting in a low structural compactness, which is not conducive to the miniaturization of the motor. In addition, the number of assembly processes increases, and the number of failure points also increases. Utility Model Content

[0004] Purpose of the invention: In order to overcome the deficiencies in the prior art, the utility model provides a mid-mounted motor for an urban power-assisted bicycle with a compact structure, small size and easy assembly.

[0005] Technical Solution: To achieve the above-mentioned objectives, the mid-mounted motor for a city power-assisted bicycle of the present invention comprises a housing composed of a first half-shell and a second half-shell; a motor assembly, a reduction transmission assembly, a data acquisition assembly, and a control module are mounted within the housing; a coaxially arranged torque output sleeve and a human input shaft are also mounted on the housing; the motor assembly is capable of transmitting power to the torque output sleeve via the reduction transmission assembly; the reduction transmission assembly includes a transition shaft arranged parallel to the torque output sleeve; the motor assembly comprises a stator, a rotor, and a central shaft;

[0006] The first half shell has a first cavity for accommodating the stator and the rotor, and a second cavity for accommodating the data acquisition assembly; the stator is fixed in the first cavity, and the rotor and the stator are arranged coaxially; the second half shell has a third cavity for accommodating the reduction transmission assembly;

[0007] A fixed cover plate located at the mouth of the first cavity is fixed in the housing, and first bearings supporting the central axis of the motor assembly are respectively installed on the fixed cover plate and the bottom of the first cavity;

[0008] The second half shell and the fixed cover plate are respectively equipped with second bearings for supporting the transition shaft; in addition, the first half shell is equipped with a third bearing for supporting the human input shaft, and the second half shell is equipped with a fourth bearing for supporting the torque output sleeve.

[0009] The control module includes a main control board fixed on the fixed cover plate, and the main control board and the motor assembly are respectively arranged on two sides of the fixed cover plate.

[0010] Furthermore, a separation cover is installed in the shell; a first gear is installed on the transition shaft, and the middle shaft has a gear portion meshing with the first gear; the gear portion and the first gear are both placed in the separation cover.

[0011] Furthermore, the partition cover has a recessed portion that extends downward into the second cavity, and the data acquisition assembly is placed in the recessed portion. The data acquisition assembly has a portion fixed in the recessed portion, which facilitates installation of the data acquisition assembly. Some components of the data acquisition assembly can be first fixed in the recessed portion, and then the partition cover is fixed to the first half shell, thereby greatly reducing the difficulty of installation.

[0012] Furthermore, the transition shaft is provided with a second gear, and in this solution, the second gear and the transition shaft are integrally formed; the reduction transmission assembly also includes a third gear sleeved on the torque output sleeve, and the third gear is engaged with the second gear; between the first gear and the third gear, at least one is provided with a one-way clutch between the first gear and the shaft on which it is located, and in this solution, a first one-way clutch is provided between the first gear and the transition shaft.

[0013] Furthermore, in the first solution, one end of the torque output sleeve is fixed relative to the human input shaft, and the other end has an output spline portion. In actual use, the two ends of the human input shaft are respectively connected to the pedals, and the output spline portion is connected to the sprocket. In this solution, the human input shaft and the torque output sleeve always rotate synchronously, and the two establish a fixed connection relationship through the fitted internal spline and external spline. The human input shaft and the motor assembly can both output torque to the torque output sleeve independently. When the motor assembly outputs torque to the torque output sleeve independently, the human input shaft rotates with the torque output sleeve. When the human input shaft outputs torque to the torque output sleeve independently, due to the presence of the first one-way clutch, the rotor will not rotate accordingly.

[0014] Furthermore, in the second embodiment, a second one-way clutch is disposed between one end of the torque output sleeve and the human input shaft, and an output spline portion is disposed at the other end. A needle bearing is disposed between the torque output sleeve and the human input shaft. In this embodiment, both the human input shaft and the motor assembly can independently output torque to the torque output sleeve, and the output of torque by one of the two to the torque output sleeve does not affect the other.

[0015] Furthermore, the data acquisition assembly includes a strain gauge fixed to the torque output sleeve, a rotating circuit board, and a fixed circuit board fixedly mounted relative to the housing. The strain gauge is connected to the rotating circuit board, and wireless power and signal transmission are possible between the rotating circuit board and the fixed circuit board. Specifically, both the rotating circuit board and the fixed circuit board have coils, and signal and power transmission is achieved between the two via the principle of electromagnetic induction. The fixed circuit board is connected to the main control board. When the torque output sleeve is torsionally twisted, the strain gauge deforms, thereby generating an electrical signal. The rotating circuit board acquires the electrical signal and processes it to obtain torque data transmitted from the human input shaft to the torque output sleeve. The data is then transmitted to the fixed circuit board via wireless communication, and the fixed circuit board then transmits the data to the main control board. At the same time, the fixed circuit board can wirelessly transmit power to the rotating circuit board to maintain the operation of the rotating circuit board.

[0016] Furthermore, the rotating circuit board is fixed on a bracket, and a cadence sensor is also mounted on the bracket; the bracket is axially fixed relative to the torque output sleeve via a first buckle.

[0017] Furthermore, the outer wall of the torque output sleeve is provided with a circumferential groove for the first buckle to be embedded in, and the bracket is further provided with a second buckle for acting on the edge of the cadence sensor.

[0018] Furthermore, a signal connection connector and a power connection connector connected to the main control board are installed on the outer wall of the shell, which can facilitate the access of signals and power.

[0019] Beneficial effects: The mid-mounted motor of the urban power-assisted bicycle of the utility model has the following beneficial effects:

[0020] (1) The motor housing has a complete outer shape. By setting a fixed cover plate inside, it can not only provide reliable support for the central shaft and the transition shaft, but also reduce the distance between the transition shaft and the central shaft, thereby improving the compactness of the structure. This makes the overall size of the central motor small, the number of parts is reduced, and the number of assembly processes is reduced.

[0021] (2) The various parts inside the housing are arranged reasonably, and the main control board is integrated into the housing, which can make full use of the space, avoid the need for an external controller, and make the mid-mounted motor smaller in size. In this way, the installation space required for the mid-mounted motor on the bicycle is reduced, which can effectively reduce the presence of the mid-mounted motor.

[0022] (2) By providing a separation cover, the transmission gear can be separated from the main control board, thereby preventing grease from the transmission part from splashing onto the main control board and causing malfunctions. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Outline diagram of a mid-mounted motor for a city power-assisted bicycle;

[0024] Figure 2 The structural diagram of the mid-mounted motor of the city power-assisted bicycle after the second half shell is hidden;

[0025] Figure 3 A cross-sectional structural diagram of a mid-mounted motor for a city power-assisted bicycle;

[0026] Figure 4 This is the structural diagram of the data acquisition component;

[0027] Figure 5 This is a structural diagram of the first one-way clutch.

[0028] In the figure: 1-housing; 11-first half-housing; 12-second half-housing; 13-first cavity; 14-second cavity; 15-third cavity; 2-motor assembly; 21-stator; 22-rotor; 23-middle shaft; 23a-gear unit; 3-reduction transmission assembly; 31-transition shaft; 32-first gear; 33-second gear; 34-first one-way clutch; 341-wedge block; 342-annular spring; 343-outer sleeve; 35-third gear; 4-data acquisition assembly; 4 1-strain gauge; 42-rotating circuit board; 43-fixed circuit board; 44-bracket; 44a-first buckle; 44b-second buckle; 45-cadence sensor; 45a-rib; 5-control module; 51-main control board; 6-torque output sleeve; 61-output spline; 71-fixed cover; 72-first bearing; 73-second bearing; 74-partition cover; 74a-recessed portion; 75-third bearing; 76-fourth bearing; 77-needle bearing; 8-human input shaft. DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with the accompanying drawings.

[0030] like Figure 1-2 The mid-mounted motor of the city power-assisted bicycle shown includes a housing 1, which is composed of a first half-shell 11 and a second half-shell 12. The housing 1 contains a motor assembly 2, a reduction transmission assembly 3, a data acquisition assembly 4, and a control module 5. The housing 1 also contains a coaxially arranged torque output sleeve 6 and a human input shaft 8. The motor assembly 2 can transmit power to the torque output sleeve 6 via the reduction transmission assembly 3. The reduction transmission assembly 3 includes a transition shaft 31 arranged parallel to the torque output sleeve 6. The motor assembly 2 consists of a stator 21, a rotor 22, and a central shaft 23. The length of the human input shaft 8 is 135mm-145mm, and in this embodiment, it is preferably 139.5mm. The distance between the transition shaft 31 and the human input shaft 8 is 40-45mm, and in this embodiment, it is preferably 42.65mm.

[0031] The first half shell 11 has a first cavity 13 for accommodating the stator 21 and the rotor 22, and also has a second cavity 14 for accommodating the data acquisition component 4; the stator 21 is fixed in the first cavity 13, and the rotor 22 and the stator 21 are arranged coaxially; the second half shell 12 has a third cavity 15 for accommodating the reduction transmission component 3.

[0032] like Figure 3 As shown, a fixed cover plate 71 located at the mouth of the first cavity 13 is fixed in the housing 1 , and first bearings 72 supporting the central axis 23 of the motor assembly 2 are respectively installed on the fixed cover plate 71 and the bottom of the first cavity 13 .

[0033] The second half shell 12 and the fixed cover plate 71 are respectively provided with second bearings 73 for supporting the transition shaft 31 ; in addition, the first half shell 11 is provided with a third bearing 75 for supporting the human input shaft 8 , and the second half shell 12 is provided with a fourth bearing 76 for supporting the torque output sleeve 6 .

[0034] The control module 5 includes a main control board 51 fixed on the fixed cover 71 . The main control board 51 and the motor assembly 2 are respectively disposed on both sides of the fixed cover 71 .

[0035] The above-described structure, with the provision of a fixed cover plate 71, not only reliably supports the center axle 23 and transition shaft 31, but also reduces the distance between the transition shaft 31 and the center axle 23, thereby enhancing the compactness of the structure. Furthermore, the rational layout of the various components within the housing 1, and the integration of the main control board 51 within the housing 1, fully utilize the space, eliminate the need for an external controller, and miniaturize the overall center motor. This reduces the installation space required by the center motor on the bicycle, effectively reducing its presence.

[0036] Preferably, a separator cover 74 is installed in the housing 1; a first gear 32 is mounted on the transition shaft 31, and a gear portion 23a is provided on the central shaft 23 for meshing with the first gear 32; both the gear portion 23a and the first gear 32 are housed in the separator cover 74. The separator cover 74 serves to separate the transmission gear from the main control board 51, preventing grease from the transmission from splashing onto the main control board 51 and causing malfunctions.

[0037] The partition cover 74 has a recessed portion 74a that extends downwardly into the second cavity 14, and the data acquisition assembly 4 is positioned within the recessed portion 74a. The data acquisition assembly 4 has a portion secured within the recessed portion 74a, which facilitates installation of the data acquisition assembly 4. Some components of the data acquisition assembly 4 can be secured within the recessed portion 74a before the partition cover 74 is secured to the first half-shell 11, significantly simplifying installation.

[0038] Preferably, the transition shaft 31 has a second gear 33. In this embodiment, the second gear 33 is integrally formed with the transition shaft 31. The reduction transmission assembly 3 also includes a third gear 35 sleeved on the torque output sleeve 6 and meshing with the second gear 33. A one-way clutch is provided between at least one of the first gear 32 and the third gear 35 and the shaft on which it is located. In this embodiment, a first one-way clutch 34 is provided between the first gear 32 and the transition shaft 31. The pitch diameter of the third gear 35 is preferably 64 mm.

[0039] like Figure 5 As shown, the first one-way clutch 34 includes multiple wedges 341 mounted circumferentially and an annular spring 342. The wedges 341 have arcuate surfaces and asymmetrical obtuse-angled surfaces, with the obtuse-angled surfaces having a distal surface farther from the center and a proximal surface closer to the center. The wedges 341 have slots for the annular spring 342 to engage, and the annular spring 342 acts on all of the wedges 341. When the rotational speed of the first gear 32 exceeds that of the transition shaft 31, the distal surfaces of the wedges 341 act on the first gear 32, engaging the first gear 32 with the transition shaft 31. When the rotational speed of the first gear 32 is equal to or less than that of the transition shaft 31, the annular spring 342 acts on each wedge 341, quickly disengaging the first one-way clutch 34. Furthermore, the first one-way clutch 34 also includes an outer sleeve 343 fixed relative to the first gear 32. The wedges 341 act on the outer sleeve 343, thereby acting on the first gear 32.

[0040] In the first embodiment, one end of the torque output sleeve 6 is fixed relative to the human input shaft 8, and the other end has an output spline portion 61. In actual use, the two ends of the human input shaft 8 are respectively connected to the pedals, and the output spline portion 61 is connected to the sprocket. In this solution, the human input shaft 8 and the torque output sleeve 6 always rotate synchronously, and the two establish a fixed connection relationship through the fitted internal spline and external spline. The human input shaft 8 and the motor assembly 2 can both output torque to the torque output sleeve 6 independently. When the motor assembly 2 outputs torque to the torque output sleeve 6 independently, the human input shaft 8 rotates following the torque output sleeve 6. When the human input shaft 8 outputs torque to the torque output sleeve 6 independently, the rotor 22 will not rotate accordingly due to the presence of the first one-way clutch 34.

[0041] In the second embodiment, a second one-way clutch is disposed between one end of the torque output sleeve 6 and the human input shaft 8, and an output spline portion 61 is disposed at the other end. A needle roller bearing 77 is disposed between the torque output sleeve 6 and the human input shaft 8. In this embodiment, both the human input shaft 8 and the motor assembly 2 can independently output torque to the torque output sleeve 6, and the output of torque by one of the two to the torque output sleeve 6 will not affect the other.

[0042] The data acquisition assembly 4 includes a strain gauge 41 fixed to the torque output sleeve 6, a rotating circuit board 42, and a fixed circuit board 43 fixedly mounted relative to the housing 1. The strain gauge 41 is connected to the rotating circuit board 42, and wireless power and signal transmission between the rotating circuit board 42 and the fixed circuit board 43 is possible. Specifically, both the rotating circuit board 42 and the fixed circuit board 43 have coils, and signal and power transmission between the two is achieved through the principle of electromagnetic induction. The fixed circuit board 43 is connected to the main control board 51. When the torque output sleeve 6 is torsionally subjected to force, the strain gauge 41 deforms, thereby generating an electrical signal. The rotating circuit board 42 captures the electrical signal and processes it to obtain torque data transmitted from the human input shaft 8 to the torque output sleeve 6. The rotating circuit board 42 then transmits the data to the fixed circuit board 43 via wireless communication. The fixed circuit board 43 then transmits the data to the main control board 51. Simultaneously, the fixed circuit board 43 can wirelessly transmit power to the rotating circuit board 42 to maintain its operation.

[0043] like Figure 4 As shown, the rotating circuit board 42 is fixed to a bracket 44, which also has a cadence sensor 45 mounted thereon. The bracket 44 is axially fixed relative to the torque output sleeve 6 by a first clip 44a. Specifically, the outer wall of the torque output sleeve 6 has a circumferential groove into which the first clip 44a fits. The bracket 44 also has a second clip 44b that acts on the edge of the cadence sensor 45.

[0044] A signal connection connector 52 and a power connection connector 53 connected to the main control board 51 are installed on the outer wall of the housing 1, so as to facilitate the access of signals and power.

[0045] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A mid-mounted motor for a city power-assisted bicycle, comprising a housing (1), the housing (1) consisting of a first half-shell (11) and a second half-shell (12); a motor assembly (2), a reduction transmission assembly (3), a data acquisition assembly (4) and a control module (5) are installed in the housing (1); a torque output sleeve (6) and a human input shaft (8) arranged coaxially are also installed on the housing (1); the motor assembly (2) can transmit power to the torque output sleeve (6) via the reduction transmission assembly (3); the reduction transmission assembly (3) includes a transition shaft (31) arranged parallel to the torque output sleeve (6); the motor assembly (2) consists of a stator (21), a rotor (22) and a central shaft (23); Its characteristics are: The first half shell (11) has a first cavity (13) for accommodating the stator (21) and the rotor (22), and also has a second cavity (14) for accommodating the data acquisition component (4); the second half shell (12) has a third cavity (15) for accommodating the reduction transmission component (3); A fixed cover plate (71) located at the mouth of the first cavity (13) is fixed in the housing (1), and a first bearing (72) for supporting the central axis (23) of the motor assembly (2) is respectively installed on the fixed cover plate (71) and the bottom of the first cavity (13); The second half shell (12) and the fixed cover plate (71) are respectively provided with second bearings (73) for supporting the transition shaft (31); The control module (5) comprises a main control board (51) fixed on the fixed cover plate (71).

2. The mid-mounted motor for a city power-assisted bicycle according to claim 1, characterized in that: A separation cover (74) is also installed in the housing (1); a first gear (32) is installed on the transition shaft (31); the central shaft (23) has a gear portion (23a) meshing with the first gear (32); the gear portion (23a) and the first gear (32) are both placed in the separation cover (74).

3. The mid-mounted motor for a city power-assisted bicycle according to claim 2, characterized in that: The separation cover (74) has a recessed portion (74a) recessed into the second cavity (14), and the data acquisition component (4) is placed in the recessed portion (74a).

4. The mid-mounted motor for a city power-assisted bicycle according to claim 2, characterized in that: The transition shaft (31) is provided with a second gear (33); the reduction transmission assembly (3) further comprises a third gear (35) sleeved on the torque output sleeve (6), the third gear (35) being engaged with the second gear (33); and a one-way clutch is provided between at least one of the first gear (32) and the third gear (35) and the shaft on which it is located.

5. The mid-mounted motor for a city power-assisted bicycle according to claim 1, characterized in that: One end of the torque output sleeve (6) is fixed relative to the human input shaft (8), and the other end has an output spline portion (61).

6. The mid-mounted motor for a city power-assisted bicycle according to claim 1, characterized in that: A second one-way clutch is provided between one end of the torque output sleeve (6) and the manpower input shaft (8), and the other end has an output spline portion (61).

7. The mid-mounted motor for a city power-assisted bicycle according to claim 4, characterized in that: The data acquisition component (4) includes a strain gauge (41) fixed on the torque output sleeve (6), and a rotating circuit board (42), and also includes a fixed circuit board (43) fixedly installed relative to the housing (1), the strain gauge (41) is connected to the rotating circuit board (42), the rotating circuit board (42) and the fixed circuit board (43) can wirelessly transmit power and wirelessly transmit signals, and the fixed circuit board (43) is connected to the main control board (51).

8. The mid-mounted motor for a city power-assisted bicycle according to claim 7, characterized in that: The rotating circuit board (42) is fixed on a bracket (44), and a cadence sensor (45) is also mounted on the bracket (44); the bracket (44) is axially fixed relative to the torque output sleeve (6) via a first buckle (44a).

9. The mid-mounted motor for a city power-assisted bicycle according to claim 8, characterized in that: The outer wall of the torque output sleeve (6) is provided with a circumferential groove for the first buckle (44a) to be embedded, and the bracket (44) is also provided with a second buckle (44b) acting on the edge of the cadence sensor (45).

10. The mid-mounted motor for a city power-assisted bicycle according to claim 1, characterized in that: A signal connection connector (52) and a power connection connector (53) connected to the main control board (51) are mounted on the outer wall of the housing (1).

Images