A three-speed mid-mounted motor with automatic gear shifting

Abstract

The present invention discloses a three-speed mid-mounted motor with automatic gear shifting, which relates to the field of mid-mounted motors. The key points of its technical solution include a central shaft mechanism and an assist driving mechanism; the central shaft mechanism includes a central shaft, and an input transmission assembly, a first one-way clutch assembly, a centrifugal clutch assembly and an output transmission assembly are respectively arranged on the central shaft; the input transmission assembly includes a pedal power input unit connected to the central shaft to receive the pedal input speed, and an assist input unit connected to the assist driving mechanism to receive the assist input speed; the central shaft mechanism includes the following transmission paths: from the input transmission assembly, the first one-way clutch assembly to the output transmission assembly; and from the input transmission assembly, the centrifugal clutch assembly to the output transmission assembly. The present invention can achieve automatic gear shifting according to the speed, can improve the riding experience and comfort, and can reduce the overall volume of the motor, facilitating the installation of the whole vehicle.

Description

Technical Field

[0001] The present invention relates to the field of mid-drive motors, and more particularly, to a three-speed mid-drive motor with automatic gear shifting. Background Art

[0002] Currently, mid-drive motors commonly used in the market are paired with external variable speeds or internal variable speed hubs of rear hubs. The external variable speed adjusts the position of the chain through a finger shifter and a rear derailleur, and the internal variable speed hub adjusts the angle of the rear derailleur through a finger shifter. However, the way of matching the mid-drive motor with the transmission makes the structure of the whole vehicle complex and not easy to install.

[0003] In order to simplify the structure and installation of the whole vehicle, mid-drive motors with integrated transmissions have now emerged.

[0004] For example, a Chinese patent with the publication number CN112407135A discloses a mid-drive motor with multi-gear speed adjustment, which includes a central shaft mechanism, an assist driving mechanism, and a speed change mechanism carried between the central shaft mechanism and the assist driving mechanism.

[0005] For example, a Chinese patent with the publication number CN113184106A discloses a mid-drive variable speed motor, which includes a central shaft mechanism, a speed change mechanism, an assist driving mechanism, and a gear shifting driving mechanism.

[0006] Although the above two mid-drive motors both integrate the speed change function, they both require the rider to actively adjust, resulting in the riding experience and comfort still needing to be improved; moreover, the speed change mechanism as an independent module makes the overall volume of the motor larger, which is not conducive to the installation of the whole vehicle. Summary of the Invention

[0007] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a three-speed mid-drive motor with automatic gear shifting, which can automatically shift gears according to the rotation speed, can improve the riding experience and comfort, and can reduce the overall volume of the motor, facilitating the installation of the whole vehicle.

[0008] To achieve the above purpose, the present invention provides the following technical solutions:

[0009] A three-speed mid-drive motor with automatic gear shifting, including a central shaft mechanism and an assist driving mechanism; the central shaft mechanism includes a central shaft, and an input transmission assembly, a first one-way clutch assembly, a centrifugal clutch assembly, and an output transmission assembly are respectively arranged on the central shaft;

[0010] The input transmission assembly includes a pedal power input unit connected to the central shaft to receive the pedal input rotation speed, and an assist input unit connected to the assist driving mechanism to receive the assist input rotation speed;

[0011] The central shaft mechanism includes the following transmission paths:

[0012] From the input transmission assembly, the first one-way clutch assembly to the output transmission assembly; and,

[0013] From the input transmission assembly, the centrifugal clutch assembly to the output transmission assembly.

[0014] Further, the input transmission assembly includes a planet carrier, planet gears, a fixed ring gear, and a sun gear sleeve connected to the centrifugal clutch assembly; the foot power input unit, the boost input unit, and the first one-way clutch assembly are respectively connected to the planet carrier.

[0015] Further, a second one-way clutch assembly is provided between the foot power input unit and the planet carrier.

[0016] Further, an inner stop is provided on the planet carrier for cooperating with the second one-way clutch assembly.

[0017] Further, the planet gears include a second-gear planet gear and a third-gear planet gear, and the ring gear cooperates with the third-gear planet gear; the sun gear sleeve includes a second-gear sun gear sleeve for cooperating with the second-gear planet gear and a third-gear sun gear sleeve for cooperating with the third-gear planet gear; the centrifugal clutch assembly includes a second-gear centrifugal clutch assembly connected to the second-gear sun gear sleeve and a third-gear centrifugal clutch assembly connected to the third-gear sun gear sleeve; after passing through the second-gear sun gear sleeve and the second-gear centrifugal clutch assembly, the third-gear sun gear sleeve is connected to the third-gear centrifugal clutch assembly.

[0018] Further, the first one-way clutch assembly includes a one-way clutch inner ring integrally formed on the planet carrier.

[0019] Further, a fixed ring connected to the boost input unit is provided on the outer side wall of the planet carrier, or the boost input unit is integrally formed on the outer side wall of the planet carrier.

[0020] Further, the centrifugal clutch assembly includes a clutch buffer frame, a clutch outer ring, and a clutch driving member; a reset elastic member is provided between the clutch buffer frame and the clutch outer ring, and an auxiliary reset structure is provided between the clutch buffer frame and the clutch driving member.

[0021] Further, the auxiliary reset structure includes a driving boss provided on the inner end wall of the clutch buffer frame, and a driving extension portion cooperating with the driving boss is provided at the end of the clutch driving member.

[0022] Further, the boost driving mechanism includes a motor assembly and a one-way transmission reduction assembly carried between the motor assembly and the boost input unit.

[0023] In summary, the present invention has the following beneficial effects:

[0024] 1. The present invention integrates a centrifugal clutch assembly on the central shaft mechanism to achieve automatic shifting and speed change, thereby improving the riding experience and comfort.

[0025] 2. Integrating the centrifugal clutch assembly on the central shaft mechanism can reduce the overall volume of the motor and facilitate the installation of the whole vehicle.

[0026] 3. Integrate two planet gears on a planet carrier, and then configure two sun shaft sleeves as the input transmission components, which cooperate with two centrifugal clutch assemblies to achieve an automatic three-speed structure, reducing the number of parts and assembly processes and the axial dimension, thereby reducing the overall volume of the motor.

[0027] 4. Add a reset elastic member and an auxiliary reset structure to the centrifugal clutch assembly to assist in downshifting, thereby meeting the rider's conversion requirements for speed and torque, optimizing the riding experience, and increasing comfort. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the overall structure of a three-speed mid-mounted motor with automatic shifting in the embodiment.

[0029] Figure 2 It is a schematic diagram of the internal structure of a three-speed mid-mounted motor with automatic shifting in the embodiment.

[0030] Figure 3 It is a partial component cross-sectional view of a three-speed mid-mounted motor with automatic shifting in the embodiment.

[0031] Figure 4 It is a schematic diagram of the structure of the planet carrier in the embodiment.

[0032] Figure 5 It is a schematic diagram of the structure of the three-speed centrifugal clutch assembly in the embodiment Figure 1 ;

[0033] Figure 6 It is a schematic diagram of the structure of the three-speed centrifugal clutch assembly in the embodiment Figure 2 ;

[0034] Figure 7 It is a schematic diagram of the structure of the three-speed centrifugal clutch assembly in the embodiment Figure 3 ;

[0035] Figure 8 It is a schematic diagram of the structure of the three-speed centrifugal clutch assembly in the embodiment Figure 4 ;

[0036] Figure 9 It is a schematic diagram of the structure of the three-speed clutch buffer bracket in the embodiment.

[0037] In the figure: 1. Central axis; 21. Planet carrier; 211. Fixed ring; 212. Wheel groove; 213. Inner stop; 214. Inner ring of one-way clutch; 22. Second-gear planet gear; 23. Second-gear sun shaft sleeve; 24. Third-gear planet gear; 25. Third-gear sun shaft sleeve; 26. Pedal power input unit; 261. Second one-way clutch assembly; 27. Ring gear; 28. Boost input unit; 29. First one-way clutch assembly; 31. Output cylinder; 32. Output end cover; 41. Second-gear clutch buffer frame; 42. Second-gear clutch outer ring; 44. Second-gear clutch inner ring; 45. Second-gear clutch output plate; 51. Third-gear clutch buffer frame; 511. Third-gear inner boss; 512. Third-gear driving boss; 52. Third-gear clutch outer ring; 521. Third-gear outer boss; 53. Third-gear clutch driving member; 531. Third-gear driving extension; 54. Third-gear clutch inner ring; 55. Third-gear clutch output plate; 56. Third-gear centrifugal flyweight; 561. Third-gear driving shaft; 57. Third-gear reset elastic member; 58. Third-gear driving ring; 581. Third-gear release groove; 61. Motor assembly; 62. Motor shaft; 63. Motor output gear; 64. Reduction input gear; 65. Reduction shaft; 66. Reduction output gear; 7. Tooth disc; 8. Pedal. Detailed implementation mode

[0038] The present invention will be further described in detail below with reference to the accompanying drawings.

[0039] This specific embodiment is only an interpretation of the present invention, and it is not a limitation of the present invention. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

[0040] Embodiment:

[0041] A three-speed mid-mounted motor with automatic gear shifting, referring to Figures 1 to 3 , which includes a central axis mechanism and a boost driving mechanism; the central axis mechanism includes a central axis 1, and an input transmission assembly, a first one-way clutch assembly 29, a centrifugal clutch assembly, and an output transmission assembly are respectively arranged on the central axis; the input transmission assembly includes a pedal power input unit 26 connected to the central axis 1 to receive the pedal input speed, and a boost input unit 28 connected to the boost driving mechanism to receive the boost input speed; in this embodiment, the central axis mechanism includes the following transmission paths: from the input transmission assembly, the first one-way clutch assembly 29 to the output transmission assembly; and, from the input transmission assembly, the centrifugal clutch assembly to the output transmission assembly; in this embodiment, the centrifugal clutch assembly is integrated on the central axis mechanism, and automatic gear shifting can be realized according to the speed, so that the riding experience and comfort can be improved, and the overall volume of the motor can be reduced, which is convenient for the installation of the whole vehicle.

[0042] Referring to Figures 1 to 3, the mid-mounted motor in this embodiment further includes a housing that encloses the central shaft mechanism and the assist driving mechanism; both ends of the central shaft 1 protrude from the housing, and pedals 8 are respectively connected to both ends of the central shaft 1; the rider drives the central shaft 1 to rotate through the pedals 8 to achieve pedal power input; one end of the output rotating assembly protrudes from the housing, and a sprocket 7 located outside the housing is provided thereon, and the power output of the mid-mounted motor is achieved through the sprocket 7.

[0043] Referring to Figure 2 and Figure 3 , the assist driving mechanism in this embodiment includes a motor assembly 61 and a one-way transmission and reduction assembly carried between the motor assembly 61 and the assist input unit 28; by using the one-way transmission and reduction assembly, the rotation speed of the motor assembly 61 can be transmitted to the assist input unit 28, while the rotation speed of the assist input unit 28 cannot be transmitted to the motor assembly 61; specifically, the one-way transmission and reduction assembly includes a reduction shaft 65, a reduction input gear 64 is provided at one end of the reduction shaft 65, and a reduction output gear 66 is provided at the other end; a motor output gear 63 meshing with the reduction input gear 64 is provided on the motor shaft 62 of the motor assembly 61, and the reduction output gear 66 meshes with the assist input unit 28; a unit clutch, specifically a one-way bearing, is provided between the reduction shaft 65 and the reduction input gear 64, so that the rotation speed of the motor shaft 62 can be transmitted to the assist input unit 28 through the motor output gear 63, the reduction input gear 64, the one-way clutch, the reduction shaft 65 and the reduction output gear 66, while the assist input unit 28 cannot drive the reduction input gear 64 to rotate to achieve one-way transmission; in other optional embodiments, the structures of the motor assembly 61 and the one-way transmission and reduction assembly, as well as the installation position of the one-way clutch, can all be adjusted as needed, which is not limited here, as long as the assist driving mechanism can provide an assist rotation speed.

[0044] Referring to Figures 1 to 3 , specifically, the input transmission assembly in this embodiment includes a planet carrier 21, planet gears, a fixed ring gear 27, and a sun gear sleeve connected to the centrifugal clutch assembly; the pedal power input unit 26, the assist input unit 28, and the first one-way clutch assembly 29 are respectively connected to the planet carrier 21; in this embodiment, the ring gear 27 and the housing are in interference fit to make the ring gear 27 stationary; in other optional embodiments, the ring gear 27 and the housing can also be fixedly connected by fasteners, which is not limited here.

[0045] Referring to Figure 3, in this embodiment, a second one-way clutch assembly 261 is provided between the foot pedal power input unit 26 and the planet carrier 21. Specifically, the second one-way clutch assembly 261 in this embodiment is a ratchet and pawl assembly. Of course, in other alternative embodiments, the second one-way clutch assembly 261 can also adopt other one-way clutches, such as one-way bearings, etc., which are not limited herein. In this embodiment, an inner stop 213 for cooperating with the second one-way clutch assembly is provided at one end of the planet carrier 21, that is, the ratchet of the ratchet and pawl assembly is embedded in the inner stop 213 by interference fit, and the pawl seat is integrally formed on the foot pedal power input unit 26, so as to reduce the number of parts and assembly processes, and effectively control the axial dimension and radial dimension. In other alternative embodiments, the foot pedal power input unit and the pawl seat can also be two parts and then fixedly connected, which is not limited herein.

[0046] Referring to Figure 3 and Figure 4 , specifically, the foot pedal power input unit 26 is sleeved on the central shaft 1, and the central shaft 1 and the foot pedal power input unit 26 are linked through spline fit. When stepping forward, the central shaft 1 drives the planet carrier 21 to rotate through the foot pedal power input unit 26 and the second one-way clutch assembly 261. When stepping backward, through the second one-way clutch assembly 261, the central shaft 1 will not drive the planet carrier 21 to rotate.

[0047] Referring to Figure 1 and Figure 3 , specifically, in this embodiment, the planet gears include a second-gear planet gear 22 and a third-gear planet gear 24. Among them, the ring gear 27 cooperates with the third-gear planet gear 24, and the planet carrier 21 is respectively provided with wheel grooves 212 for cooperating with the second-gear planet gear 22 and the third-gear planet gear 24. In this embodiment, the second-gear planet gear 22 and the third-gear planet gear 24 share a planet shaft, that is, a planet shaft passes through a second-gear planet gear 22 and a third-gear planet gear 24 at the same time, so as to facilitate assembly. In this embodiment, the third-gear planet gear 24 is close to the outside of the central shaft mechanism, and the cooperation of the ring gear 27 and the third-gear planet gear 24 facilitates the connection of the ring gear 27 with the housing. The sun shaft sleeve includes a second-gear sun shaft sleeve 23 for cooperating with the second-gear planet gear 22 and a third-gear sun shaft sleeve 25 for cooperating with the third-gear planet gear 24. The centrifugal clutch assembly includes a second-gear centrifugal clutch assembly connected to the second-gear sun shaft sleeve 23 and a third-gear centrifugal clutch assembly connected to the third-gear sun shaft sleeve 25. After the third-gear sun shaft sleeve 25 passes through the second-gear sun shaft sleeve 23 and the second-gear centrifugal clutch assembly, it is connected to the third-gear centrifugal clutch assembly. In this embodiment, the cooperation of the second-gear centrifugal clutch assembly and the third-gear centrifugal clutch assembly can achieve three-speed shifting and improve the riding experience. At the same time, in this embodiment, the second-gear planet gear 22 and the third-gear planet gear are respectively provided on a planet carrier 21, and then the second-gear sun shaft sleeve 23 and the third-gear sun shaft sleeve 25 are respectively used for output, which can reduce the number of parts and assembly processes and reduce the axial dimension.

[0048] Referring to Figure 3 and Figure 4 , specifically, in this embodiment, a needle bearing is provided between the third gear sun gear sleeve 25 and the middle shaft 1, a needle bearing is provided between the second gear sun gear sleeve 23 and the third gear sun gear sleeve 25, and a bearing is provided between the second gear sun gear sleeve 23 and the planet carrier 21. The use of needle bearings helps to reduce the radial dimension; in this embodiment, the first one-way clutch assembly 29 includes a one-way clutch inner ring 214 integrally formed on the planet carrier 21. Specifically, in this embodiment, the first one-way clutch assembly 29 is a ratchet and pawl assembly, and the one-way clutch inner ring 214 is a pawl seat. Integrally forming the one-way clutch inner ring 214 on the planet carrier 21 can reduce the number of parts and assembly processes; a fixing ring 211 connected to the assist input unit 28 is provided on the outer side wall of the planet carrier 21. Specifically, in this embodiment, the assist input unit 28 is a gear, and it is fixedly connected to the fixing ring 211 by bolts; the fixing ring 211 is located between the second gear planet gear 22 and the third gear planet gear 24, and the assist input unit 28 is used to connect to an assist driving mechanism, so as to be able to control the overall axial dimension; of course, in other alternative embodiments, the assist input unit 28 can also be integrally formed on the outer side wall of the planet carrier 21, which is not limited herein.

[0049] Referring to Figure 1 and Figure 3 , in this embodiment, the output transmission assembly includes an output cylinder 31 and an output end cover 32 connected to the output cylinder 31. The axial extension section of the output end cover 32 protrudes from the housing and is used to connect to the tooth disc 7; the first one-way clutch assembly 29 is arranged between the planet carrier 21 and the output cylinder 31. In the first gear state, the rotation speed of the planet carrier 21 is directly transmitted to the output cylinder 31 through the first one-way clutch assembly 29; the second gear centrifugal clutch assembly and the third gear centrifugal clutch assembly are respectively arranged between the second gear sun gear sleeve 23 and the output cylinder 31. In the second gear state, the rotation speed of the planet carrier 21 is transmitted to the output cylinder 31 through the second gear sun gear sleeve 23 and the second gear centrifugal clutch assembly. At this time, the rotation speed of the output cylinder 31 is greater than that of the planet carrier 21, and the first one-way clutch assembly 29 is in an overrunning state; in the third gear state, the rotation speed of the planet carrier 21 is transmitted to the output cylinder 31 through the third gear sun gear sleeve 25 and the third gear centrifugal clutch assembly. At this time, the rotation speed of the output cylinder 31 is greater than that of the planet carrier 21 and the second gear sun gear sleeve 23, so both the first one-way clutch assembly 29 and the second gear centrifugal clutch assembly are in an overrunning state.

[0050] Referring to Figure 3In this embodiment, the second gear centrifugal clutch assembly and the third gear centrifugal clutch assembly both realize state change according to the output speed, that is, the second gear centrifugal clutch assembly and the third gear centrifugal clutch assembly both realize state change according to the speed of the output cylinder 31, thereby realizing automatic gear shifting; of course, in other optional embodiments, the centrifugal clutch assembly can also realize state change according to the input speed, which is not limited here; specifically, the second gear centrifugal clutch assembly includes a second gear clutch buffer frame 41, a second gear clutch outer ring 42, a second gear clutch driving member, a second gear clutch inner ring 44, a second gear clutch output plate 45, a second gear driving ring and a second gear centrifugal throw block; wherein one end of the second gear sun shaft sleeve 23 is meshed with the second gear planetary gear 22, and the other end is embedded in the second gear clutch buffer frame 41, and the second gear sun shaft sleeve 23 and the second gear clutch buffer frame 41 are splined to realize circumferential linkage, and the second gear clutch buffer frame 41 and the output cylinder 31 are connected. The second gear clutch output plate 45 is provided with a bearing; the inner end of the second gear clutch output plate 45 is connected to the second gear clutch inner ring 44, and the outer end is connected to the output tube 31; the second gear centrifugal block is arranged on the second gear clutch output plate 45, and when the speed of the output tube 31 reaches the shifting speed, the second gear centrifugal block is thrown away under the action of centrifugal force, driving the second gear drive ring to rotate, so that the second gear clutch driving member is released, and the second gear clutch outer ring 42 and the second gear clutch inner ring 44 are transmitted through the second gear clutch driving member; at this time, the rotation speed of the second gear sun shaft sleeve 23 is transmitted to the output tube 31 through the second gear clutch buffer frame 41, the second gear clutch outer ring, the second gear clutch driving member, the second gear clutch inner ring 44 and the second gear clutch output plate 45; if the second gear centrifugal clutch assembly realizes the state change according to the input speed, the second gear clutch buffer frame 41 is connected to the output tube 31, and the second gear clutch output plate 45 is separated from the output tube 31 and connected to the second gear sun shaft sleeve 23.

[0051] Reference Figure 3 as well as Figures 5 to 9, specifically, the third-gear centrifugal clutch assembly includes a third-gear clutch buffer frame 51, a third-gear clutch outer ring 52, a third-gear clutch driving member 53, a third-gear clutch inner ring 54, a third-gear clutch output plate 55, a third-gear centrifugal flyweight 56, and a third-gear driving ring 58. A third-gear release groove 581 that cooperates with the third-gear clutch driving member 53 is formed on the third-gear driving ring 58; the third-gear centrifugal flyweight 56 is arranged on the third-gear clutch output plate 55, and the third-gear driving ring 58 and the third-gear centrifugal flyweight 56 are respectively located on both sides of the third-gear clutch output plate 55; a third-gear driving shaft 561 that passes through the third-gear clutch output plate 55 and is connected to the third-gear driving ring 58 is arranged on the third-gear centrifugal flyweight 56; one end of the third-gear sun gear sleeve 25 meshes with the third-gear planet gear 24, and the other end is embedded in the third-gear clutch buffer frame 51, and the third-gear sun gear sleeve 25 and the third-gear clutch buffer frame 51 are in circumferential linkage through spline fit; a bearing is arranged between the third-gear clutch buffer frame 51 and the central shaft 1, and the third-gear clutch output plate 55 is connected to the output cylinder 31; when the rotational speed of the output cylinder 31 reaches the shift speed, the third-gear centrifugal flyweight 56 is thrown open under the action of centrifugal force and drives the third-gear driving ring 58 to rotate, so that the third-gear clutch driving member 53 pops up and is embedded in the third-gear release groove 581, then the third-gear clutch inner ring 54 and the third-gear clutch outer ring 52 are driven through the third-gear clutch driving member 53; at this time, the rotational speed of the third-gear sun gear sleeve 25 is transmitted to the output cylinder 31 through the third-gear clutch buffer frame 51, the third-gear clutch outer ring 52, the third-gear clutch driving member 53, the third-gear clutch inner ring 54, and the third-gear clutch output plate 55; in this embodiment, the second-gear centrifugal flyweight and the third-gear centrifugal flyweight 56 are cross-arranged between the second-gear clutch output plate 45 and the third-gear clutch output plate 55, which can effectively control the axial dimension.

[0052] Refer to Figures 6 to 9 , in this embodiment, a reset elastic member is arranged between the clutch buffer frame and the clutch outer ring, and an auxiliary reset structure is arranged between the clutch buffer frame and the clutch driving member; the cooperation of the reset elastic member and the auxiliary reset structure is beneficial to realizing a smooth downshift, thereby meeting the rider's conversion requirements for speed and torque, optimizing the riding experience, and increasing comfort.

[0053] Refer to Figures 6 to 9 , specifically, taking the third-gear centrifugal clutch assembly as an example, in this embodiment, third-gear inner bosses 511 are uniformly arranged along the circumferential direction on the inner side wall of the third-gear clutch buffer frame 51, and third-gear outer bosses 521 that cooperate with the third-gear inner bosses 511 are uniformly arranged along the circumferential direction on the outer side wall of the third-gear clutch outer ring 52; after the third-gear inner bosses 511 and the third-gear outer bosses 521 come into contact, circumferential linkage between the third-gear clutch buffer frame 51 and the third-gear clutch outer ring 52 is realized; buffer transmission between the third-gear clutch buffer frame 51 and the third-gear clutch outer ring 52 is realized through the third-gear inner bosses 511 and the third-gear outer bosses 521, which is beneficial to improving the riding experience.

[0054] Refer to Figures 6 to 9, in this embodiment, two third-gear return elastic members 57 are provided between the third-gear clutch buffer frame 51 and the third-gear clutch outer ring 52; specifically, the third-gear return elastic member 57 is V-shaped, one end of which is bent and embedded in the end face of the third-gear clutch outer ring 52, and the other end is bent and embedded in the inner end face of the third-gear clutch buffer frame 51; when the third-gear clutch driving member 53 is in a pressed state, the third-gear return elastic member 57 is in an open state; after the third-gear clutch driving member 53 rebounds and combines with the third-gear clutch outer ring 52, the third-gear return elastic member 57 is compressed; in this embodiment, the third-gear auxiliary return structure includes third-gear driving bosses 512 evenly distributed along the circumferential direction on the inner end wall of the third-gear clutch buffer frame 51, and a third-gear driving extension 531 cooperating with the third-gear driving bosses 512 is provided at the end of the third-gear clutch driving member 53; after the gears are combined during riding, the third-gear inner boss 511 of the third-gear clutch buffer frame 51 contacts the third-gear outer boss 521 of the third-gear clutch outer ring 52, and the third-gear return elastic member 57 is compressed; when the rider decelerates and the foot pedal stops pedaling, the third-gear clutch buffer frame 51 and the third-gear clutch outer ring 52 are in a state without driving force, and at this time, the third-gear return elastic member 57 releases elastic force, causing the third-gear clutch buffer frame 51 and the third-gear clutch outer ring 52 to reset; among them, the third-gear clutch buffer frame 51 is pushed to rotate in the reverse direction by the third-gear return elastic member 57. During the rotation of the third-gear clutch buffer frame 51, the third-gear driving boss 512 on its inner end face contacts the third-gear driving extension 531 at the end of the third-gear clutch driving member 53 and presses the third-gear clutch driving member 53 downward; because the rotational speed is low and the centrifugal force is small in the deceleration state, the third-gear clutch driving member 53 will be retracted by the third-gear driving ring 58 after being pressed down, so that the third-gear centrifugal clutch assembly is in a disengaged state and will be released again after acceleration; in this embodiment, the third-gear return elastic member 57 is combined with the third-gear auxiliary return structure to assist in downshifting, so as to meet the rider's requirements for speed and torque conversion, optimize the riding experience, and increase comfort.

[0055] The working principle is as follows:

[0056] First gear: When the rider pedals, the center shaft 1 is driven to rotate, and the center shaft 1 drives the foot pedal power input unit 26 to rotate; a torque sensing component (not shown in the drawings) is provided on the foot pedal power input unit 26. After the torque sensing component collects the torque signal, the motor assembly 61 is started, and the assisted rotation speed is input to the assisted input unit 28 through the reduction output gear 66; the rotation speed of the foot pedal power input unit 26 is transmitted to the planet carrier 21 through the second one-way clutch assembly 261, and the rotation speed of the assisted input unit 28 is also transmitted to the planet carrier 21. The rotation speed of the planet carrier 21 is transmitted to the sprocket 7 through the first one-way clutch assembly 29, the output cylinder 31, and the output end cover 32, realizing riding in the first-gear state; in the first-gear state, both the second-gear centrifugal clutch assembly and the third-gear centrifugal clutch assembly are in a disengaged state.

[0057] Second gear: When the output speed reaches the second-gear shift critical point, the second-gear centrifugal clutch assembly engages, and the rotation speed of the planet carrier 21 is transmitted to the gear disc 7 through the second-gear sun shaft sleeve 23, the second-gear centrifugal clutch assembly, the output cylinder 31, and the output end cover 32, realizing riding in the second-gear state; in the second-gear state, the rotation speed of the output cylinder 31 is greater than that of the planet carrier 21, and the first one-way clutch assembly 29 is in an overrunning state, while the third-gear centrifugal clutch assembly remains disengaged.

[0058] Third gear: When the output speed reaches the third-gear shift critical point, the third-gear centrifugal clutch assembly engages, and the rotation speed of the planet carrier 21 is transmitted to the gear disc 7 through the third-gear sun shaft sleeve 25, the third-gear centrifugal clutch assembly, the output cylinder 31, and the output end cover 32, realizing riding in the third-gear state; in the third-gear state, the rotation speed of the output cylinder 31 is greater than that of the planet carrier 21 and the second-gear sun shaft sleeve 23, and both the first one-way clutch assembly 29 and the second-gear centrifugal clutch assembly are in an overrunning state.

[0059] Downshift: The rider decelerates and stops pedaling. At this time, the rotation speed of the output cylinder 31 decreases. When the rotation speed of the output cylinder 31 drops to the third-gear shift critical point, the third-gear centrifugal flyweight 56 resets and contracts under the action of the elastic force, cooperating with the third-gear return elastic member 57 and the third-gear auxiliary return structure, so that the third-gear centrifugal clutch assembly smoothly resets to the disengaged state. At this time, the gear returns to the second gear; when the rotation speed of the output cylinder 31 drops to the second-gear shift critical point, the second-gear centrifugal clutch assembly resets to the disengaged state, and the gear continues to return to the first gear.

Claims

1. A three-speed mid-drive motor with automatic gear shifting, characterized in that: it includes a central shaft mechanism and an assist drive mechanism; the central shaft mechanism includes a central shaft, and an input transmission component, a first one-way clutch component, a centrifugal clutch component and an output transmission component are respectively arranged on the central shaft; the input transmission component includes a pedal power input unit connected to the central shaft to receive the pedal input speed, and an assist input unit connected to the assist drive mechanism to receive the assist input speed; the central shaft mechanism includes the following transmission paths: from the input transmission component, the first one-way clutch component to the output transmission component; and, from the input transmission component, the centrifugal clutch component to the output transmission component; the input transmission component includes a planet carrier, planet gears, a fixedly arranged ring gear and a sun gear sleeve connected to the centrifugal clutch component; the pedal power input unit, the assist input unit and the first one-way clutch component are respectively connected to the planet carrier; a second one-way clutch component is arranged between the pedal power input unit and the planet carrier; the planet gears include a second-gear planet gear and a third-gear planet gear, and the ring gear cooperates with the third-gear planet gear; the sun gear sleeve includes a second-gear sun gear sleeve that cooperates with the second-gear planet gear and a third-gear sun gear sleeve that cooperates with the third-gear planet gear; the centrifugal clutch component includes a second-gear centrifugal clutch component connected to the second-gear sun gear sleeve and a third-gear centrifugal clutch component connected to the third-gear sun gear sleeve; after passing through the second-gear sun gear sleeve and the second-gear centrifugal clutch component, the third-gear sun gear sleeve is connected to the third-gear centrifugal clutch component.

2. The three-speed mid-drive motor with automatic gear shifting according to claim 1, characterized in that: an inner stop is arranged on the planet carrier and cooperates with the second one-way clutch component.

3. The three-speed mid-drive motor with automatic gear shifting according to claim 1, characterized in that: the first one-way clutch component includes a one-way clutch inner ring integrally formed on the planet carrier.

4. The three-speed mid-drive motor with automatic gear shifting according to claim 1, characterized in that: a fixing ring connected to the assist input unit is arranged on the outer side wall of the planet carrier, or the assist input unit is integrally formed on the outer side wall of the planet carrier.

5. The three-speed mid-drive motor with automatic gear shifting according to claim 1, characterized in that: the centrifugal clutch component includes a clutch buffer frame, a clutch outer ring and a clutch driving member; a reset elastic member is arranged between the clutch buffer frame and the clutch outer ring, and an auxiliary reset structure is arranged between the clutch buffer frame and the clutch driving member.

6. The three-speed mid-drive motor with automatic gear shifting according to claim 5, characterized in that: the auxiliary reset structure includes a driving boss arranged on the inner end wall of the clutch buffer frame, and a driving extension part cooperating with the driving boss is arranged at the end of the clutch driving member.

7. The three-speed mid-drive motor with automatic gear shifting according to claim 1, characterized in that: the assist drive mechanism includes a motor component and a one-way transmission and reduction component carried between the motor component and the assist input unit.

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