CN219857509U - Stepless speed change central motor - Google Patents

Abstract

The utility model relates to a stepless speed change middle motor, which comprises a shell, a power-assisted motor, a generator and a middle shaft, wherein a left half shaft is connected with a torque sensor, the torque sensor is connected with a first planet carrier, a gear ring support frame is supported on the first planet carrier, a first gear ring and a third gear ring are fixedly connected on the gear ring support frame, the first gear ring is meshed with a first planet wheel, and the first planet wheel is meshed with a first sun wheel to form a first speed change structure; the third gear ring is meshed with a right side gear of the duplex planet gear, a left side gear of the duplex planet gear is meshed with a second gear ring fixed on the shell, the left side gear is meshed with a third sun gear, and the third sun gear is fixedly connected with a generator rotor to form a second speed change structure; the input gear of the first planet carrier is meshed with the transition gear and is meshed with the output shaft gear of the power-assisted motor. The beneficial effects are that: the manual power and the power-assisted motor power are intersected with each other to be output after being changed in speed by the first planet carrier of the planetary gear speed change mechanism, and a rider can ride with the most comfortable force and pedal frequency.

Description

Continuously variable speed mid-mounted motor

Technical field

The utility model belongs to the technical field of mid-mounted motors for power-assisted bicycles, and particularly relates to a continuously variable speed mid-mounted motor.

Background technique

Currently, most of the mid-mounted transmissions of electric bicycles on the market use gear transmission mechanisms to connect the motor and the crankset. By increasing the number of gears, the shifting function of the mid-mounted transmission system is achieved. This transmission system has high requirements on the strength and life of the gears, and the production cost is high. At the same time, there may be incoherent transmission during the transmission. The existing technology introduces a bicycle equipped with a built-in continuously variable mid-motor, which can automatically adjust the output speed according to the riding resistance to achieve continuously variable speed. For example, the applicant disclosed an adaptive continuously variable speed mid-mounted motor with patent application number 202211527942.6, which includes a casing, a power-assisted motor, a main motor, a generator and a central shaft. The characteristics of the power-assisted motor are: The rotor is connected to the output shaft of the booster motor through a one-way clutch of the booster motor. The rotor of the main motor is coaxially connected to the output shaft of the booster motor through a one-way clutch of the main motor. The output shaft of the booster motor is supported on the housing through a bearing. The gear at the output end of the output shaft of the booster motor is meshed with an output reduction mechanism; the rotor of the generator is connected to the central shaft, and the rotor of the generator is coaxially connected to the planetary speed-increasing mechanism. The generator is connected to the booster motor and the main gear. The motor forms a continuously variable speed motor combination structure. The Chinese patent with patent authorization announcement number CN107685828B discloses a continuously variable transmission device for an electric bicycle, which includes a first motor, a second motor, a central shaft and a planetary gear mechanism coaxially arranged with the central shaft; the planetary gear mechanism It includes a sun gear, an inner and outer ring gear, a planet carrier and a planet gear. The sun gear is sleeved on the central shaft through a clutch. The inner and outer ring gears are provided with inner teeth and outer teeth of the ring gear. The planets The gears are evenly distributed on the planet carrier in the circumferential direction and mesh with the inner teeth of the sun gear and the ring gear respectively. The first motor meshes with the outer teeth of the ring gear through gears. The axial side of the planet carrier meshes with the second motor through gears. The other side of the shaft is provided with an output crankset assembly fixedly connected thereto. The utility model realizes stepless speed change output by adding a motor, ensuring smooth and consistent speed change. Although the above two mid-mounted motors can achieve stepless speed change within a relatively large output speed range, in this structure only the human power is output through the speed change mechanism, while the power of the assist motor is not output through the speed change mechanism, causing the power assist motor to Working within a wide speed range results in low efficiency. At the same time, the second patented technology has a more prominent defect, that is, since the action point of the force is not placed on the housing (the first motor serves as the input end, the central axis and the second motor are not Perform power output; the input power is transmitted to the planetary gear through the first output shaft gear and the inner and outer ring gears, and the sun gear generates a clutch between the needle roller clutch and the central axis, and the planetary gear mechanism rotates around the central axis driven by the planetary gear. The output crankset assembly rotates accordingly, driving the electric bicycle forward.) This structure will cause the possibility of the pedals rotating rapidly in the opposite direction when the person's feet are not stepping on the pedals, which is very dangerous.

Utility model content

The purpose of this utility model is to overcome the shortcomings of the above technology and provide a continuously variable speed mid-mounted motor. Through the synergistic function of the combination of two sets of planetary gear transmission structures, both the artificial power and the power of the booster motor are output through variable speed, thereby improving Boost motor efficiency and rider comfort.

In order to achieve the above purpose, the utility model adopts the following technical solution: a continuously variable speed mid-mounted motor, including a casing, a booster motor, a generator, a central shaft and a planetary gear transmission structure, and is characterized by: the central shaft runs through the power generation The central shaft includes a left half shaft and a right half shaft. The left half shaft is connected to the torque sensor through the first one-way clutch. The torque sensor is connected to the first planet carrier. The left half shaft The left half-shaft supports the bearing on the housing. The right half-shaft is slidably connected to a first planet carrier. The first planet carrier has a ring gear support frame supported by the first ring gear support bearing. The ring support frame is fixed with a first ring gear and a third ring gear that is integral with it. The first ring gear meshes with the first planet gear. The first planet gear is supported on the first planet gear through the first planet gear support bearing. The first planet gear support shaft is supported on the first planet carrier, and the first planet gear meshes with the first sun gear to form the first planet gear transmission structure; the third ring gear and the right side of the double planet gear The side gear meshes. The left gear of the double planetary gear meshes with the second ring gear fixed on the housing. The left gear meshes with the third sun gear. The double planetary gear is supported on the double planetary gear through the double planetary gear support bearing. The double planet gear support shaft is supported on the second planet carrier, the second planet carrier is supported on the first planet carrier through the second planet carrier support bearing, and the third sun gear is fixedly connected to the generator rotor. , forming a second planetary gear transmission structure; a second one-way clutch is provided between the ring gear support frame and the first planetary carrier, and the outer circle of the crankset output shaft is supported by a crankset output shaft support bearing on the housing. , the inner circle of the crankset output shaft is supported on the right half-shaft of the central axis through the sun gear output shaft support bearing, the input gear on the outer circle of the first planet carrier meshes with the transition gear, and the transition gear meshes with the output shaft gear of the booster motor.

Further, the left half shaft of the central shaft is provided with a central shaft end ratchet, and the inner ring of the torque sensor is provided with a torque sensor end ratchet, forming a first one-way clutch structure.

Further, the ring gear support frame is provided with a ring gear support frame end ratchet, and the first planet carrier is provided with an output mechanism planet carrier end ratchet, forming a second one-way clutch structure.

Further, the left half shaft and the right half shaft are splined.

Further, the end face of the torque sensor is provided with rectangular teeth in the axial direction and is keyed with the rectangular teeth on the end face of the first planet carrier.

Beneficial effects: Compared with the existing technology, the utility model has a compact structure and smaller radial size, and combines the artificial power and the booster motor power in the first planetary carrier of the planetary gear transmission mechanism and outputs them after speed change, thereby preventing the speed change of the speed motor. The force affects the reverse rotation of the central axis, allowing the rider to ride at the most comfortable strength and cadence. The power-assist motor also works in a high-efficiency range, improving the efficiency of the power-assist motor and improving riding comfort.

Description of the drawings

Figure 1 is a structural cross-sectional view of the utility model's mid-mounted motor;

Figure 2 is a schematic diagram of the combination of the utility model's continuously variable transmission device and the motor;

Figure 3 is an exploded right oblique view of the central motor of the present invention;

Figure 4 is a partial enlarged view of Figure 3;

Figure 5 is an exploded left oblique view of the central motor of the present invention;

Figure 6 is a partial enlarged view of Figure 5;

Figure 7 is a schematic connection diagram of the mid-mounted motor torque sensor of the present invention;

Figure 8 is a schematic block diagram of the utility model.

In the picture: 1. Right half shaft, 1-1, Left half shaft, 1-2, Center shaft end ratchet, 1-3, Left half shaft spline, 1-4, Right half shaft spline, 1-5 , sun gear output shaft support bearing, 1-6, left half shaft support bearing, 2. torque sensor, 2-1, torque sensor end ratchet, 2-2, torque sensor end rectangular tooth, 3. first planet carrier, 3-1. The first planet carrier end ratchet, 3-2. The first planet carrier end motor power input gear, 3-3. The first planet carrier left end rectangular tooth, 4. The first planet gear support shaft, 4-1. The first planet gear support bearing, 5. The first planet gear, 6. The first ring gear, 7. The first sun gear, 7-1. The crankshaft output shaft, 7-2. The crankshaft output shaft support bearing, 8. Crankset, 9. First ring gear support frame, 9-1. First ring gear support frame end ratchet, 9-2. First ring gear support frame supports bearing, 10. Third ring gear, 11. Duplex Planetary right gear, 11-1, double planetary left gear, 11-2, double planetary support bearing, 14, second ring gear, 12, double planetary support shaft, 13, second planet Frame, 13-1. Second planet carrier support bearing, 15. Second sun gear, 16. Generator rotor, 16-1. Generator rotor support bearing, 17. Generator stator, 18. Left side housing, 19 , Right side housing, 20. Motor stator, 21. Motor rotor, 22. Motor one-way clutch, 23. Motor output shaft, 23-1. Motor output shaft gear, 23-2. Motor output shaft left support bearing, 23-3. Support bearing on the right side of the motor output shaft, 24. Motor end cover, 25. Transition gear, 25-1. Transition wheel support bearing, 26. Controller, 26-1. Riding status signal, 26-2. Charging load control signal, 27. Charging load control unit, 28. Battery.

Detailed ways

In order to understand the above-mentioned objects, features and advantages of the present invention more clearly, the present utility model will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, as long as there is no conflict, the embodiments of the present application and the features in the embodiments can be combined with each other. Many specific details are set forth in the following description to facilitate a full understanding of the present invention. The described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present utility model. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which the invention belongs. The terms used in the description of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

In each embodiment of the present invention, in order to facilitate the description but not to limit the present invention, the term "connection" used in the patent application specification and claims of the present invention is not limited to physical or mechanical connection, but can be Including electrical connections, whether direct or indirect. "Up", "Down", "Bottom", "Left", "Right", etc. are only used to express relative positional relationships. When the absolute position of the described object changes, the relative positional relationship also changes accordingly.

See the accompanying drawings for details. This embodiment provides a continuously variable speed mid-mounted motor, including a housing, a power-assisted motor, a generator, a central shaft and a planetary gear transmission structure. The central shaft runs through the generator and the planetary gear transmission structure. In the center, the central axis includes a left half shaft and a right half shaft. The left half shaft 1-1 is connected to the torque sensor 2 through the first one-way clutch. The torque sensor 2 is connected to the first planet carrier. The left half shaft is connected through the left The half-shaft support bearings 1-6 are supported on the housing. The right half-shaft is slidably connected to the first planet carrier 3. The first planet carrier 3 supports the ring gear through the first ring gear support bearing 9-2. The support frame 9 has a first ring gear 6 and a third ring gear 10 integral with the ring gear support frame 9. The first ring gear 6 meshes with the first planetary gear 5. The first planetary gear The first planet gear support bearing 4-1 is supported on the first planet gear support shaft 4, the first planet gear support shaft is supported on the first planet carrier 3, and the first planet gear 5 meshes with the first sun gear 7. The first planetary gear transmission structure; the third ring gear 10 meshes with the right gear 11 of the double planetary gear, the left gear 11-1 of the double planetary gear meshes with the second ring gear 14 fixed on the housing, and the left gear 11-1 meshes with the second ring gear 14 fixed on the housing. The side gear meshes with the third sun gear 15, and the double planet gear is supported on the double planet gear support shaft 12 through the double planet gear support bearing 11-2, and the double planet gear support shaft is supported on the second planet carrier 13 on the first planet carrier 3, the second planet carrier 13 is supported on the first planet carrier 3 through the second planet carrier support bearing 13-1, and the third sun gear 15 is fixedly connected to the generator rotor 16 to form a second planet gear transmission structure; A second one-way clutch is provided between the ring support frame 9 and the first planet carrier 3. The outer circle of the crank output shaft 7-1 is supported by the crank output shaft support bearing 7-2 on the housing. The crank output shaft The inner circle of shaft 7-1 is supported on the right half shaft 1 of the central axis through the sun gear output shaft support bearing 1-5. The input gear 3-2 on the outer circle of the first planet carrier 3 meshes with the transition gear 25, and the transition gear is with the booster motor. The output shaft gear 23-1 meshes.

The preferred solution of this embodiment is that the left half shaft 1-1 of the central axis is provided with a central axis end ratchet 1-2, and the inner ring of the torque sensor 2 is provided with a torque sensor end ratchet 2-1, forming a first one-way clutch. structure.

The preferred solution of this embodiment is that the ring gear support frame 9 is provided with a ring gear support end ratchet 9-1, and the first planet carrier 3 is provided with an output mechanism planet carrier end ratchet 3-1, forming a second unit. to the clutch structure.

A preferred solution of this embodiment is that the left half shaft and the right half shaft are splined.

The preferred solution of this embodiment is that the end face of the torque sensor 2 is provided with rectangular teeth in the axial direction and is keyed with the rectangular teeth on the end face of the first planet carrier.

Working principle of continuously variable transmission

As shown in Figure 1, the two-way power of human power and assist motor power is gathered into the first planet carrier input and output from the first sun gear. According to the basic characteristics of the NGW planetary gear system, under the condition that the planet carrier speed remains unchanged, the first When the ring gear speed changes, the speed of the first sun gear will also change.

When power is input to the first planet carrier, both the first planet wheel and the first planet carrier have a tendency to rotate in the rotation direction of the first planet carrier. The specific speed of the first sun gear and the first ring gear depends on the The size of the resistance of a ring gear. The ring gear with large resistance rotates slowly and the ring gear with small resistance rotates at fast speed. The first ring gear resistance is achieved by controlling the charging load of the generator rotor to control the generator rotor resistance. Under the condition that the input power of the planet carrier is certain, the generator rotor speed is: if the resistance of the generator rotor is large, the speed will be slow, and if the resistance is small, the speed will be fast. By controlling the size of the charging load, the generator rotor speed is controlled and then the third ring gear and the first ring gear speeds are controlled. The first sun gear speed is changed while the first planet carrier speed remains unchanged, that is, the variable speed output.

Generally, there are three types of riding conditions: uphill, flat, and downhill. For cyclists, no matter which of the above road conditions, they can always pedal at the most comfortable cadence (generally a cadence of about 60 rpm). is the most comfortable frequency), this utility model adjusts the crankset output speed increase ratio based on specific road conditions. When the rider pedals at a constant cadence, the crankset outputs at different speeds, making the rider more comfortable. Comfortable riding, while also allowing the power-assist motor to work in a high-efficiency zone.

The second ring gear 14 is fixed to the left housing 18. By engaging the second ring gear and the third ring gear at the same time through the double gear, the generator rotor can lock the third ring gear with a smaller force. In the charging load control unit Stably control the speed change process under control.

The relationship between the rider's cadence and the speed of the device of the present invention under different riding environments is further explained:

Divided into three situations: high speed, low speed and medium speed

1) When it is necessary to run in high gear, increase the charging load to lock the third ring gear, that is, the third ring is stationary, the power is input from the first planet carrier and output from the first sun gear, and the first planet carrier speed is _{nth A planet carrier} , the first sun gear’s growth rate is n _{first sun gear} , then, the growth rate ratio from the first planet carrier to the first sun gear _{i first sun gear} = n _{first sun gear} / n _{first planet carrier} = 1+Zf/Zg, where Zf is the number of teeth of the first ring gear, Zg is the number of teeth of the first sun gear, and this is the speed-increasing output;

2) When it is necessary to run in a low speed gear, the charging load is reduced to make the generator rotor idling, so that the third ring gear can rotate at the fastest speed. However, since the third ring gear is fixedly connected to the second one-way clutch, and the other end of the second one-way clutch is fixedly connected to the first planet carrier, the third ring gear is limited by the second one-way clutch, and the maximum speed of the third ring gear is only Can rotate synchronously with the first planet carrier, then the rotation speed of the first sun gear is the same as the rotation speed of the first planet carrier, and the speed increase ratio i _{first sun gear} = n _{first sun gear} / n _{first planet carrier} = 1, at this time For low speed output;

The transmission ratio of the second planetary gear transmission structure: Since the third ring gear and the first ring gear are a common body, the third ring gear drives the double gear to rotate, and the double gear drives the second sun gear and the generator rotor to increase the speed. The rotation speed of the third ring gear is n. The rotation speed of the _second sun gear is n. The rotation speed of _{the second sun gear} is n. Then, the speed increase ratio between the third ring gear and the second sun gear is i _{generator rotor} = nth _{. Second sun gear} /n _{Third ring gear} = (1+Zb/Za)/(1-ZbZd/ZcZe), where Zb is the number of teeth of the second ring gear, which is 107 teeth in this embodiment; Za is the number of teeth of the second sun gear , 43 teeth in this embodiment; Zc is the number of gear teeth on the left side of the double gear, which is 32 teeth in this embodiment; Zd is the number of gear teeth on the right side of the double gear, which is 28 teeth in this embodiment; Ze is the third tooth The number of ring teeth is 103 teeth in this embodiment; the generator rotor rotates at a speed that is twice that of the third ring gear speed of the i _{generator rotor} . The specific number of teeth belongs to the design common sense of those skilled in the art and will not be described in detail. At this time, the charging load is controlled to be 0 and the generator rotor is idling;

3) When it is necessary to run between high speed and low speed, the charging load must be controlled between the two extreme conditions 1) and 2), so that the generator rotor can run between stalled and idling. status. When the generator rotor is controlled to run in a stalled state, the third ring gear is locked, that is, the third ring gear is stationary, which is a high-speed output; when the generator rotor is controlled to run in an idling state, the maximum speed of the third ring gear is equal to the maximum speed of the third ring gear. The first planet carrier rotates synchronously, then the first sun gear speed is the same as the first planet carrier speed, which is a low-speed output; the speed increase ratio is also between 1+Zf/Zg and 1, Zf is the first ring gear The number of teeth, Zg is the number of teeth of the first sun gear. By adjusting the rotation speed of the third and first ring gears, the desired speed increase ratio is obtained, so that the riding is in the most comfortable state.

As shown in Figure 1, the power transmission of the continuously variable mid-mounted motor has two paths:

1) The artificial power transmission path is that the rider pedals to drive the bottom bracket to rotate. The left half-shaft of the bottom bracket transmits power to the torque sensor through the ratchet at the bottom of the bottom bracket and the ratchet at the torque sensor end (the first one-way clutch). The power is then transmitted to the torque sensor. Passed to the first planet carrier;

2) The motor power transmission path is that the motor power is transmitted to the motor output shaft and motor output shaft gear through the motor one-way clutch 22, and further transmitted to the first planet carrier end motor power input gear and the first planet carrier through the transition gear;

3) Artificial power and motor power meet at the first planet carrier. Both artificial power and motor power are output through variable speed, allowing the rider to ride at the most comfortable intensity and cadence, and the motor also works in a high-efficiency range.

The first planet carrier drives the first planet gear and the first planet gear is simultaneously engaged with the first ring gear and the first sun gear. As mentioned above, the rotation speed of the first sun gear is jointly determined by the rotation speed of the first planet carrier and the first ring gear. Specifically, the rotation speed of the first sun gear n _{first sun gear} = (1+Zf/Zg) * n _{first planet carrier} - Zf/Zg * n _{first ring gear} , Zf is the number of teeth of the first ring gear, and Zg is the number of teeth of the first sun gear.

The following will further explain the relationship between the specific riding conditions, the generator load and the first and second planetary gear transmission structures.

1) When the rider starts from a stopped state, the rotation speed of the chainring output shaft and the first sun gear is 0, and the load is large. The first planet carrier pushes the first planet gear, and the first planet gear further pushes the first ring gear. rotation, when the speed of the first ring gear catches up with the speed of the first planet carrier, the first planet carrier end ratchet meshes with the ring gear support end ratchet, and the first ring gear and the first planet carrier rotate synchronously. At this time, the crankset output shaft The speed increase ratio is the smallest. The speed ratio between the bottom bracket and the crankset output shaft is 1:1, that is, the speed increase ratio i=1, and it runs in a low speed gear. At the same time, the first ring gear drives the third ring gear to rotate, which further drives the second and third planetary gears and the second sun gear to rotate. The second sun gear is fixedly connected to the generator rotor and drives the generator rotor to rotate. At this time, the generator is charging. The load is adjusted to 0 and the generator rotor is idling.

2) When riding on a downhill road or flat ground with a tailwind, the bicycle has less resistance and requires less torque from the crankset, but requires a high speed. At this time, the charging load of the generator is increased, causing the generator rotor speed to decrease until the rotor is blocked, and then the third ring gear speed also becomes 0. At this time, the speed increase ratio is the largest, and the speed ratio between the bottom bracket and the crankshaft output shaft is i =1+Zf/Zg=1+102/30=4.4, where Zf is the number of teeth of the first ring gear, which is 102 teeth in this embodiment; Zg is the number of teeth of the first sun gear, which is 30 teeth in this embodiment, that is, The speed increase ratio of the disc output shaft is i=4.4, running in high gear. The cyclist rides faster at a lower cadence.

3) When riding on road conditions between the above two situations, control the charging load of the generator so that the first ring gear speed is between the bottom bracket speed and 0 speed, so that the crankshaft output shaft speed increase ratio is also between At a comfortable value between 1 and 4.4, the ride will be in the most comfortable state.

As shown in Figure 7, the continuously variable mid-mounted motor also includes a controller 26 and a charging load control unit 27. During riding, riding status signals 26-1 are collected, including wheel speed signals, pedaling torque signals, and pedaling frequency signals. , motor speed, generator speed and other signals, the controller outputs the corresponding charging load signal 26-2 to the charging load control unit 27 according to the above riding status signal, and controls the first ring gear speed by adjusting the charging load to adjust the crankset output. The purpose of the shaft speed ratio.

During the shifting process, the electricity generated by the generator is charged into the battery 28 and recycled and reused to maximize efficiency.

The above detailed description of a continuously variable speed mid-mounted motor with reference to the embodiments is illustrative rather than restrictive. In addition to being used in the bicycle field, the transmission system in the above embodiments can also be used in variable speed transmissions in other fields. , several embodiments can be enumerated according to the limited scope. Therefore, changes and modifications without departing from the overall concept of the present utility model should be within the protection scope of the present utility model.

Claims (5)

1. The utility model provides a put motor in infinitely variable speed, includes casing, helping hand motor, generator, axis and planet wheel variable speed structure, characterized by: the center shaft penetrates through the center of the generator and the planetary gear speed change structure, the center shaft comprises a left half shaft and a right half shaft, the left half shaft (1-1) is connected with a torque sensor (2) through a first one-way clutch, the torque sensor is connected with a first planet carrier (3), the left half shaft is supported on a shell through a left half shaft support bearing (1-6), the right half shaft is connected with the first planet carrier in a sliding manner, a gear ring support frame (9) is supported on the first planet carrier through a first gear ring support frame support bearing (9-2), a first gear ring (6) and a third gear ring (10) which is in common with the first gear ring are fixedly connected on the gear ring support frame, the first gear ring is meshed with the first planet carrier (5), the first planet carrier is supported on a first planet carrier support shaft (4-1) through a first planet carrier support bearing, and the first planet carrier is meshed with a first sun gear (7) to form the first planetary gear speed change structure; the third gear ring is meshed with a right gear (11) of the duplex planet gear, a left gear (11-1) of the duplex planet gear is meshed with a second gear ring (14) fixed on the shell, the left gear is meshed with a third sun gear (15), the duplex planet gear is supported on a duplex planet gear supporting shaft (12) through a duplex planet gear supporting bearing (11-2), the duplex planet gear supporting shaft is supported on a second planet carrier (13), the second planet carrier is supported on a first planet carrier through a second planet carrier supporting bearing (13-1), and the third sun gear is fixedly connected with a generator rotor (16) to form a second planet gear speed change structure; the gear ring support frame is provided with a second one-way clutch with the first planet frame, the shell is provided with an outer circle of a tooth disc output shaft (7-1) through a tooth disc output shaft supporting bearing (7-2), an inner circle of the tooth disc output shaft is supported on a right half shaft (1) of a middle shaft through a sun wheel output shaft supporting bearing (1-5), an input gear (3-2) of the outer circle of the first planet frame is meshed with a transition gear (25), and the transition gear is meshed with an output shaft gear (23-1) of the power-assisted motor.

2. The infinitely variable center motor of claim 1, wherein: the left half shaft of the middle shaft is provided with a middle shaft end ratchet (1-2), and the inner ring of the moment sensor is provided with a moment sensor end ratchet (2-1) to form a first one-way clutch structure.

3. The infinitely variable center motor of claim 1, wherein: the gear ring support frame is provided with a gear ring support frame end ratchet (9-1), and the first planet carrier is provided with an output mechanism planet carrier end ratchet (3-1) to form a second one-way clutch structure.

4. The infinitely variable center motor of claim 1, wherein: the left half shaft and the right half shaft are connected in an inserting mode through a spline.

5. The infinitely variable center motor of claim 1, wherein: rectangular teeth are axially arranged on the end face of the moment sensor and are in key joint with the rectangular teeth on the end face of the first planet carrier.