Middle motor driving system and electric moped

Abstract

The invention provides a mid-motor driving system and an electric moped. The mid-motor driving system comprises a torque sensor assembly, an output shaft assembly, a magnetic group assembly, a motor and a controller. Motor gear shafts of the motors are connected with the output shaft assemblies in a pairwise meshed mode through duplicate gears, and speed reduction is carried out on the sides of the output shaft assemblies; the output shaft assembly comprises a large gear, a one-way needle bearing, an output shaft, a third bearing, a ratchet wheel, a pawl, a ratchet ring and a tensioning piece. The torque sensor assembly is used for detecting the torque of the center shaft, the magnetic group assembly is used for detecting the rotating speed of a gear shaft of the motor, and the controller controls the torque and the rotating speed output by the motor according to the detected torque and the rotating speed. Two-stage speed reduction is adopted, and the high rotating speed of the motor rotor is converted into stable large-torque low-rotating-speed output of the output shaft. The duplicate gear is fixed through cooperation of the machine shell partition plate and the machine shell, so that the overall structure is more compact.

Description

Technical Field

[0001] The present invention relates to the field of motor technology, and in particular to a mid-mounted motor drive system and an electric power-assisted bicycle. Background Art

[0002] For electric-assisted bicycles, the motor is responsible for providing auxiliary power. The motor drive system of an electric-assisted bicycle is what sets it apart from other bicycles. When the rider pedals, sensors detect the force and speed of the pedaling, transmitting information such as speed, cadence, and torque to the controller. The controller then calculates and issues instructions to control the motor's operation. The motor outputs power at high speed and low torque, requiring a reduction system to amplify the torque and keep the output speed close to the human leg's cadence.

[0003] The output shaft of the transmission mid-motor drive system is generally a gear shaft, which converts the output speed of the rotor into the speed and torque required by the system through various levels of gears, making the overall volume larger and the torque output limited. Summary of the Invention

[0004] In view of the defects in the prior art, the purpose of the present invention is to provide a mid-mounted motor drive system and an electric power-assisted bicycle.

[0005] According to the present invention, a mid-mounted motor drive system is provided, comprising: a torque sensor assembly 101, an output shaft assembly 102, a magnetic braid assembly 103, a motor and a controller 2;

[0006] The motor gear shaft 30 of the motor is meshed with the output shaft assembly 102 in pairs through the double gear 8, and the speed is reduced on the output shaft assembly 102 side;

[0007] The output shaft assembly 102 includes: a large gear 10, a one-way needle bearing 11, an output shaft 12, a third bearing 14, a ratchet 17, a pawl 19, a ratchet ring 20 and a tensioning plate 21;

[0008] The large gear 10 is connected to the outer ring of the one-way needle roller bearing 11, the output shaft 12 is connected to the inner ring of the one-way needle roller bearing 11, the ratchet ring 20 is fixedly connected to the inner surface of the output shaft 12, the inner ring of the third bearing 14 is connected to the central shaft 16 of the torque sensor assembly 101, the ratchet 17 is connected to the outer ring of the third bearing 14, the ratchet ring 20 is coaxially arranged with the ratchet 17, and the outer circumferential surface of the ratchet 17 is provided with a plurality of mounting positions, one end of the pawl 19 is rotatably connected to the mounting position, and the tensioning piece 21 is elastically connected between the pawl 19 and the mounting position so that the other end of the pawl 19 is in contact with the inner surface of the ratchet ring 20;

[0009] The torque sensor assembly 101 is used to detect the torque of the central shaft 16, and the magnetic woven assembly 103 is used to detect the rotational speed of the motor gear shaft 30. The controller 2 controls the torque and rotational speed output by the motor according to the detected torque and rotational speed.

[0010] Furthermore, the torque sensor assembly 101 includes: the central shaft 16, the torque sensor control board 22 and the torque sleeve 23;

[0011] The torque sleeve 23 is connected to the central shaft 16 , and the torque sensor control board 22 is electrically connected to the torque sleeve 23 .

[0012] Furthermore, the magnetic encoding component 103 includes:

[0013] A magnetic weaving plate 5 , a signal magnetic steel 6 and an adapter 7 , wherein the signal magnetic steel 6 is connected to the end of the motor gear shaft 30 through the adapter 7 , and the magnetic weaving plate 5 is arranged on the outside of the signal magnetic steel 6 .

[0014] Furthermore, the motor includes: a rotor assembly 105 and a stator assembly 27;

[0015] The rotor assembly 105 includes: a rotor assembly 28 and the motor gear shaft 30;

[0016] The rotor assembly 28 is connected to the motor gear shaft 30 , and the stator assembly 27 is coaxially arranged on the outside of the rotor assembly 28 .

[0017] Furthermore, the mid-mounted motor drive system further includes: a left housing assembly 100;

[0018] The left housing assembly 100 includes: a left housing 1, a first bearing 9, and a second bearing 13. The double gear 8 is rotatably connected to the left housing 1 through the first bearing 9, and the output shaft 12 is rotatably connected to the left housing 1 through the second bearing 13.

[0019] Furthermore, the mid-mounted motor drive system further includes: a right housing assembly 106;

[0020] The right housing assembly 106 includes: a right housing 24, a fourth bearing 25, a second oil seal 26 and a fifth bearing 29. The right housing 24 is connected to the left housing 1, the central shaft 16 is rotatably connected to the right housing 24 through the fourth bearing 25, the second oil seal 26 is connected to the central shaft 16 and the right housing 24, and the motor gear shaft 30 is rotatably connected to the right housing 24 through the fifth bearing 29.

[0021] Furthermore, the mid-mounted motor drive system further includes: a casing partition assembly 104;

[0022] The casing partition assembly 104 includes: a casing partition 3, a sixth bearing 31 and a seventh bearing 33. The casing partition 3 is located between the left casing 1 and the right casing 24. The motor gear shaft 30 is rotatably connected to the casing partition 3 through the sixth bearing 31. The double gear 8 is rotatably connected to the casing partition 3 through the seventh bearing 33.

[0023] Furthermore, a waterproof pad 32 is provided at the connection between the right housing 24 and the left housing 1 , and an oil shield 4 is provided at the connection between the double gear 8 and the motor gear shaft 30 .

[0024] Furthermore, the output shaft assembly 102 further includes: a first oil seal 15 and a bushing 18 . The first oil seal 15 is connected between the middle shaft 16 and the output shaft 12 , and the bushing 18 is connected between the output shaft 12 and the left housing 1 .

[0025] An electric assisted bicycle provided according to the present invention includes the above-mentioned mid-mounted motor drive system.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The present invention uses a two-stage reduction gear. The motor rotor is connected to a first-stage gear shaft with a relatively small number of teeth. The gear shaft meshes with a large gear of a duplex gear. The small gear of the duplex gear meshes with another large gear, which is connected to the output shaft via a one-way needle roller bearing. This route converts the high speed of the motor rotor into a stable, high-torque, low-speed output on the output shaft.

[0028] The present invention fixes the double gears by cooperating with the casing partition plate and the casing, so that the overall structure is more compact. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0030] Figure 1 is a cross-sectional view of the mid-mounted motor drive system of the present invention;

[0031] Figure 2 An exploded view of the mid-mounted motor drive system of the present invention;

[0032] Figure 3 This is a working principle diagram of the double gear of the present invention;

[0033] Figure 4 Schematic diagram of the working principle of the pawl of the present invention. DETAILED DESCRIPTION

[0034] The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0035] like Figure 1 and Figure 2 As shown, a mid-mounted motor drive system provided by the present invention includes a torque sensor assembly 101, an output shaft assembly 102, a magnetic braid assembly 103, a motor and a controller 2.

[0036] like Figure 3 As shown, the end of the motor gear shaft 30 of the motor is a first-stage gear shaft with a smaller number of teeth. The first-stage gear shaft is engaged with the large gear of the double gear 8, and the small gear of the double gear 8 is engaged with the output shaft assembly 102. The speed is reduced on the output shaft assembly 102 side to convert the high speed of the motor rotor into a stable high-torque low-speed output of the output shaft.

[0037] The output shaft assembly 102 includes a large gear 10, a one-way needle roller bearing 11, an output shaft 12, a third bearing 14, a ratchet 17, a pawl 19, a ratchet ring 20, and a tensioning plate 21. The large gear 10 is connected to the outer ring of the one-way needle roller bearing 11, the output shaft 12 is connected to the inner ring of the one-way needle roller bearing 11, the ratchet ring 20 is fixedly connected to the inner surface of the output shaft 12, the inner ring of the third bearing 14 is connected to the central shaft 16 of the torque sensor assembly 101, the ratchet 17 is connected to the outer ring of the third bearing 14, the ratchet ring 20 is coaxial with the ratchet 17, and the outer circumference of the ratchet 17 is provided with multiple mounting positions. One end of the pawl 19 is rotatably connected to the mounting position, and the tensioning plate 21 is elastically connected between the pawl 19 and the mounting position, so that the other end of the pawl 19 is in contact with the inner surface of the ratchet ring 20. The torque sensor assembly 101 is used to detect the torque of the central shaft 16, and the magnetic woven assembly 103 is used to detect the rotational speed of the motor gear shaft 30. The controller 2 controls the torque and rotational speed output by the motor according to the detected torque and rotational speed.

[0038] like Figure 4As shown, all pawls 19 are divided into n groups, n is a natural number greater than or equal to 2, and the total number of pawls 19 is 3n, that is, 3 in each group. The more pawls in each group, the higher the meshing accuracy, and the smaller the torque transmitted. However, in other embodiments, the number of pawls 19 can be more, and the present invention does not limit this. Each group of pawls 19 is evenly distributed in the circumference of the ratchet 17, and the circumferential distribution of pawls 19 of different groups in the ratchet 17 forms a preset angle of dislocation (the pawls 19 of different groups are not evenly distributed in the circumference of the ratchet 17), and the dislocation angle is half of the angle subtended by each tooth of the ratchet ring 20, that is, when there are n groups of meshing pawls, the dislocation angle is 1 / n of the angle corresponding to each tooth of the ratchet ring. Therefore, only one group of pawls 19 can engage with the ratchet teeth on the inner surface of the ratchet ring 20 at the same time. Figure 4 In the embodiment, all pawls 19 are divided into two groups, the number of ratchet rings 20 is 57, and the number of pawls 19 is 6. The cadence accuracy is approximately 3.2°, which is much lower than the cadence accuracy of approximately 10° in the case of a single group of pawls 19. Therefore, the present invention can significantly reduce the number of empty pedals caused by the large size of the ratchet groove and pawl during pedaling, that is, the slippage process before the pawl engages with the ratchet teeth, thereby improving the cadence accuracy.

[0039] The torque sensor assembly 101 includes: a central shaft 16 , a torque sensor control board 22 and a torque sleeve 23 . The torque sleeve 23 is connected to the central shaft 16 , and the torque sensor control board 22 is electrically connected to the torque sleeve 23 .

[0040] The magnetic weaving assembly 103 includes: a magnetic weaving plate 5, a signal magnetic steel 6 and an adapter 7. The signal magnetic steel 6 is connected to the end of the motor gear shaft 30 through the adapter 7. The magnetic weaving plate 5 is arranged on the outside of the signal magnetic steel 6.

[0041] The motor includes a rotor assembly 105 and a stator assembly 27. The rotor assembly 105 includes a rotor assembly 28 and a motor gear shaft 30. The rotor assembly 28 is connected to the motor gear shaft 30, and the stator assembly 27 is coaxially arranged on the outside of the rotor assembly 28.

[0042] The mid-mounted motor drive system further includes a left housing assembly 100 , a right housing assembly 106 and a housing partition assembly 104 .

[0043] The left housing assembly 100 includes: a left housing 1, a first bearing 9, a second bearing 13, a double gear 8 rotatably connected to the left housing 1 via the first bearing 9, and an output shaft 12 rotatably connected to the left housing 1 via the second bearing 13. The right housing assembly 106 includes: a right housing 24, a fourth bearing 25, a second oil seal 26, and a fifth bearing 29. The right housing 24 is connected to the left housing 1, the central shaft 16 is rotatably connected to the right housing 24 via the fourth bearing 25, the second oil seal 26 is connected to the central shaft 16 and the right housing 24, and the motor gear shaft 30 is rotatably connected to the right housing 24 via the fifth bearing 29. The casing partition assembly 104 includes a casing partition 3, a sixth bearing 31, and a seventh bearing 33. The casing partition 3 is located between the left casing 1 and the right casing 24. The motor gear shaft 30 is rotatably connected to the casing partition 3 via the sixth bearing 31, and the duplex gear 8 is rotatably connected to the casing partition 3 via the seventh bearing 33. A waterproof gasket 32 is provided at the connection between the right casing 24 and the left casing 1, and an oil shield 4 is provided at the connection between the duplex gear 8 and the motor gear shaft 30. A first oil seal 15 is connected between the center shaft 16 and the output shaft 12, and a bushing 18 is connected between the output shaft 12 and the left casing 1.

[0044] When a person steps on the middle shaft 16, the middle shaft 16 drives the torque sleeve 23, which in turn drives the output shaft 12 to output torque through the ratchet 17, ratchet teeth 19, and ratchet ring 20. Because the ratchet mechanism in this solution is a high-precision ratchet mechanism, it can accurately capture the magnitude of the foot-stepping torque in conjunction with the torque sensor assembly 101. The torque sensor assembly 101 feeds back the accurate torque changes to the controller 2, which then precisely controls the speed and torque of the motor's rotor assembly 105. The speed output by the rotor assembly 105 passes through the motor gear shaft 30, and then the double gear 8 transmits power to the output shaft assembly 102, thereby controlling the torque output of the motor.

[0045] In the description of this application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0046] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. The embodiments of this application and the features in the embodiments may be combined with each other in any manner unless there is a conflict.

Claims

1. A mid-mounted motor drive system, characterized in that: include: A torque sensor assembly (101), an output shaft assembly (102), a magnetic spool assembly (103), a motor and a controller (2); The motor gear shaft (30) of the motor is meshed with the output shaft assembly (102) in pairs via a double gear (8), and speed reduction is performed on the output shaft assembly (102) side; The output shaft assembly (102) comprises: a large gear (10), a one-way needle bearing (11), an output shaft (12), a third bearing (14), a ratchet (17), a pawl (19), a ratchet ring (20) and a tensioning plate (21); The large gear (10) is connected to the outer ring of the one-way needle roller bearing (11), the output shaft (12) is connected to the inner ring of the one-way needle roller bearing (11), the ratchet ring (20) is fixedly connected to the inner surface of the output shaft (12), the inner ring of the third bearing (14) is connected to the central shaft (16) of the torque sensor assembly (101), the ratchet (17) is connected to the outer ring of the third bearing (14), the ratchet ring (20) and the ratchet (17) are coaxially arranged, and the outer peripheral surface of the ratchet (17) is provided with a plurality of mounting positions, one end of the pawl (19) is rotatably connected to the mounting position, and the tensioning plate (21) is elastically connected between the pawl (19) and the mounting position so that the other end of the pawl (19) fits the inner surface of the ratchet ring (20); The torque sensor assembly (101) is used to detect the torque of the central shaft (16), the magnetic woven assembly (103) is used to detect the rotational speed of the motor gear shaft (30), and the controller (2) controls the torque and rotational speed output by the motor according to the detected torque and rotational speed.

2. The mid-mounted motor drive system according to claim 1, characterized in that: The torque sensor assembly (101) comprises: the central shaft (16), a torque sensor control board (22) and a torque sleeve (23); The torque sleeve (23) is connected to the central shaft (16), and the torque sensor control board (22) is electrically connected to the torque sleeve (23).

3. The mid-mounted motor drive system according to claim 1, characterized in that: The magnetic encoding assembly (103) comprises: A magnetic weaving plate (5), a signal magnetic steel (6) and an adapter (7), wherein the signal magnetic steel (6) is connected to the end of the motor gear shaft (30) through the adapter (7), and the magnetic weaving plate (5) is arranged on the outside of the signal magnetic steel (6).

4. The mid-mounted motor drive system according to claim 1, characterized in that: The motor comprises: a rotor assembly (105) and a stator assembly (27); The rotor assembly (105) includes: a rotor assembly (28) and the motor gear shaft (30); The rotor assembly (28) is connected to the motor gear shaft (30), and the stator assembly (27) is coaxially arranged outside the rotor assembly (28).

5. The mid-mounted motor drive system according to claim 1, characterized in that: The central motor drive system further comprises: a left housing assembly (100); The left housing assembly (100) comprises: a left housing (1), a first bearing (9), and a second bearing (13); the double gear (8) is rotatably connected to the left housing (1) via the first bearing (9); and the output shaft (12) is rotatably connected to the left housing (1) via the second bearing (13).

6. The mid-mounted motor drive system according to claim 5, characterized in that: The mid-mounted motor drive system further includes: a right housing assembly (106); The right housing assembly (106) includes: a right housing (24), a fourth bearing (25), a second oil seal (26) and a fifth bearing (29); the right housing (24) is connected to the left housing (1); the middle shaft (16) is rotatably connected to the right housing (24) through the fourth bearing (25); the second oil seal (26) is connected to the middle shaft (16) and the right housing (24); and the motor gear shaft (30) is rotatably connected to the right housing (24) through the fifth bearing (29).

7. The mid-mounted motor drive system according to claim 6, characterized in that: The central motor drive system further includes: a casing partition assembly (104); The casing partition assembly (104) comprises: a casing partition (3), a sixth bearing (31) and a seventh bearing (33); the casing partition (3) is located between the left casing (1) and the right casing (24); the motor gear shaft (30) is rotatably connected to the casing partition (3) via the sixth bearing (31); and the double gear (8) is rotatably connected to the casing partition (3) via the seventh bearing (33).

8. The mid-mounted motor drive system according to claim 7, characterized in that: A waterproof pad (32) is provided at the connection between the right housing (24) and the left housing (1), and an oil shield (4) is provided at the connection between the double gear (8) and the motor gear shaft (30).

9. The mid-mounted motor drive system according to claim 5, characterized in that: The output shaft assembly (102) further comprises: a first oil seal (15) and a bushing (18); the first oil seal (15) is connected between the middle shaft (16) and the output shaft (12); and the bushing (18) is connected between the output shaft (12) and the left housing (1).

10. An electric power-assisted bicycle, characterized in that: The invention comprises a mid-mounted motor drive system as described in any one of claims 1 to 9.

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