Power system for electric power-assisted bicycle and electric power-assisted bicycle

Abstract

The invention belongs to the technical field of bicycles, and discloses a power system for an electric power-assisted bicycle and the electric power-assisted bicycle. The power system for the electric power-assisted bicycle comprises a shell, a middle shaft, an electric power-assisted device and an electric speed regulation device, the middle shaft is rotatably installed on the shell, the electric power-assisted device comprises a power-assisted motor and a power-assisted transmission mechanism, and the middle shaft is rotatably installed on the shell; the electric speed regulation device comprises a speed regulation motor and a speed regulation transmission mechanism; the power-assisted transmission mechanism is matched with the power-assisted motor, the speed reduction and torque increase effects can be achieved, auxiliary force is provided for a rider, the riding difficulty of the rider is lowered, and the riding fatigue feeling of the rider is relieved; the rotating axis of the input end of the power-assisted transmission mechanism coincides with the rotating axis of the middle shaft, double-motor double-shaft driving can be achieved, the structure is more compact, and occupied space is smaller; the speed regulation transmission mechanism is driven by the speed regulation motor to drive the first output wheel to rotate, stepless speed change of the first output wheel can be achieved, no impact feeling exists in the speed change process, and the riding experience of a rider is improved.

Description

Technical Field

[0001] The present application relates to the technical field of bicycles, and particularly to a power system for an electric assist bicycle and an electric assist bicycle. Background Art

[0002] An electric assist bicycle not only has the lightness and convenience of a bicycle, but also can effectively make up for the burden when the bicycle goes uphill, against the wind, or carries goods, effectively improving the riding experience of the rider. The power system of an electric assist bicycle usually includes a torque sensor and an electric drive device. Its working principle is to use a force sensor to sense the force of the rider stepping on the pedal, then judge the riding intention of the rider according to the magnitude of the force, and then control the electric drive device to provide a corresponding driving force. Most common power systems are single-motor power systems, that is, power systems that use a single motor to achieve electric assistance, which can provide auxiliary power but do not have a continuously variable transmission function and cannot meet the needs of riders for high-performance assist bicycles.

[0003] A dual-motor power system in the related art includes a bottom bracket, a first electric drive device, and a second electric drive device. Among them, the bottom bracket is used to connect the pedal, and the functions of electric assistance and speed change can be realized through the first electric drive device and the second electric drive device. However, this dual-motor power system has the following disadvantages: 1) The central axes of the bottom bracket, the central axis of the first electric drive device, and the central axis of the second electric drive device of this system are not collinear. The transmission of three central axes by two motors makes the distribution of components relatively scattered, resulting in a larger size of the entire system and requiring a larger installation space to be reserved on the vehicle body, which will affect the assembly of other components of the bicycle; 2) In this system, different gear sets are driven by the first electric drive device and the second electric drive device to mesh to achieve the function of shifting gears. Since shifting gears will bring a sense of impact, the riding experience of the rider is not good.

[0004] This part provides background information related to the present application, and these background information are not necessarily prior art. Summary of the Invention

[0005] The purpose of the present application is to solve or at least alleviate part or all of the above problems. For this reason, the purpose of the present application is to provide a power system for an electric assist bicycle and an electric assist bicycle, which are not only structurally compact and occupy a small space, but also can achieve continuously variable transmission and can improve the riding experience of the rider.

[0006] To achieve the above objectives, the present application adopts the following technical solutions:

[0007] In a first aspect, the present application provides a power system for an electric assist bicycle, including:

[0008] A housing;

[0009] The central shaft is rotatably mounted on the housing, and the central shaft is used for fixedly connecting with the crank of a bicycle;

[0010] The electric assist device includes an assist motor and an assist transmission mechanism. The output end of the assist motor is coaxially and drivingly connected to the input end of the assist transmission mechanism, and the rotation axis of the input end of the assist motor coincides with the rotation axis of the central shaft;

[0011] The electric speed regulation device includes a speed regulation motor and a speed regulation transmission mechanism. The speed regulation transmission mechanism has two input ends. Its first input end is coaxially and drivingly connected to the output end of the speed regulation motor, and the second input end is drivingly connected to the output end of the assist transmission mechanism; the rotation axis of the output end of the speed regulation motor is parallel to the rotation axis of the central shaft;

[0012] The first output wheel is drivingly connected to the output end of the speed regulation transmission mechanism, and the first output wheel is used for drivingly connecting with the rear wheel of a bicycle.

[0013] As an alternative to the power system for the electric assist bicycle, the assist transmission mechanism includes an assist planetary gear mechanism and an assist output driving wheel. The output end of the assist motor is drivingly connected to the input end of the assist planetary gear mechanism. The output end of the assist planetary gear mechanism is drivingly connected to the assist output driving wheel. The assist output driving wheel is drivingly connected to the second input end of the speed regulation transmission mechanism.

[0014] As an alternative to the power system for the electric assist bicycle, the assist planetary gear mechanism includes an assist sun gear, assist planet gears and an assist ring gear. The assist sun gear, as the input end of the assist planetary gear mechanism, is coaxially and drivingly connected to the output end of the assist motor; the assist planet gears, as the output end of the assist planetary gear mechanism, are coaxially and drivingly connected to the assist output driving wheel; the assist ring gear is fixedly connected to the housing.

[0015] As an alternative to the power system for the electric assist bicycle, the assist planet gears include a planet gear carrier and a planet gear set. The planet gear carrier is coaxially and drivingly connected to the assist output driving wheel; when the number of the planet gear sets is one, the planet gear set meshes with the assist sun gear and the assist ring gear at the same time;

[0016] When the number of the planet gear sets is two, the assist planet gears further include a connecting shaft rotatably connected to the planet gear carrier. Both of the two planet gear sets include planetary gears, and the number of the planetary gears in each planet gear set is the same as the number of the connecting shafts. The corresponding planetary gears in the two planet gear sets are respectively connected to both ends of the corresponding connecting shaft. One of the planet gear sets meshes with the assist sun gear, and the other planet gear set meshes with the assist ring gear.

[0017] As an alternative to the power system for the electric assist bicycle, the speed regulation transmission mechanism includes a speed regulation planetary gear mechanism and an assist output driven wheel, and the output end of the assist transmission mechanism is in transmission connection with the assist output driven wheel; the speed regulation planetary gear mechanism has two input ends, its first input end is in transmission connection with the output end of the speed regulation motor, the second input end is connected to the assist output driven wheel, and the output end of the speed regulation planetary gear mechanism is in transmission connection with the first output wheel.

[0018] As an alternative to the power system for the electric assist bicycle, the number of the speed regulation planetary gear mechanisms is at least one, and each speed regulation planetary gear mechanism includes a speed regulation sun gear, a speed regulation planetary gear and a speed regulation ring gear; when the number of the speed regulation planetary gear mechanisms is one, the speed regulation sun gear is in coaxial transmission connection with the output end of the speed regulation motor, the speed regulation ring gear is in coaxial transmission connection with the assist output driven wheel; the speed regulation planetary gear serves as the output end of the speed regulation planetary gear mechanism and is in transmission connection with the first output wheel;

[0019] When the number of the speed regulation planetary gear mechanisms is two or more, each speed regulation planetary gear mechanism is arranged in sequence from the direction where the speed regulation motor is located to the direction where the first output wheel is located, and the speed regulation sun gear of the first speed regulation planetary gear mechanism is in transmission connection with the output end of the speed regulation motor, the speed regulation ring gear of the last speed regulation planetary gear mechanism is in transmission connection with the assist output driven wheel; the speed regulation planetary gear of the last speed regulation planetary gear mechanism is in transmission connection with the first output wheel.

[0020] As an alternative to the power system for the electric assist bicycle, the power system for the electric assist bicycle further includes a human power transmission device, the human power transmission device includes a force sensor, a first human power transmission mechanism and a second human power transmission mechanism, the first human power transmission mechanism is used for transmitting and connecting the bottom bracket shaft and the speed regulation transmission mechanism, the force sensor is installed on the first human power transmission mechanism and is used for detecting the pedaling frequency and pedaling force of the rider; the second human power transmission mechanism is used for transmitting and connecting the bottom bracket shaft and the rear wheel.

[0021] As an alternative to the power system for the electric assist bicycle, the first human power transmission mechanism includes a human power output driving wheel and a human power output driven wheel that is in transmission connection with the human power output driving wheel, the human power output driving wheel is in coaxial transmission connection with the bottom bracket shaft through a first clutch, and the human power output driven wheel is coaxially fixed with the assist output driven wheel; and / or

[0022] The second manual transmission mechanism includes a second output wheel, which is coaxially connected to the middle shaft through a second clutch, and the second output wheel is used for drivingly connecting with the rear wheel of the bicycle.

[0023] As an alternative solution for the power system of the electric-assisted bicycle, the manual output driving wheel and the manual output driven wheel are drivingly connected by a chain or a synchronous belt or an idler wheel; and / or

[0024] The power-assisted output driving wheel and the power-assisted output driven wheel are drivingly connected by a chain or a synchronous belt or an idler wheel; and / or

[0025] The second output wheel and the rear wheel are drivingly connected by a chain or a synchronous belt.

[0026] In a second aspect, the present application provides an electric-assisted bicycle, including a vehicle body and the power system of the electric-assisted bicycle as described in any one of the above, and the power system of the electric-assisted bicycle is installed on the vehicle body.

[0027] The beneficial effects of the present application are as follows:

[0028] The power system of the electric-assisted bicycle provided by the present application, by using the power-assisted transmission mechanism in cooperation with the power-assisted motor, can achieve the effect of speed reduction and torque increase, provide auxiliary force for the rider, reduce the riding difficulty of the rider, and relieve the riding fatigue of the rider; by setting the rotation axis of the input end of the power-assisted transmission mechanism to coincide with the rotation axis of the middle shaft, dual-motor and dual-axis drive can be achieved, the structure is more compact, and the space occupation is smaller; by using the speed-regulating motor to drive the speed-regulating transmission mechanism to drive the first output wheel to rotate, stepless speed change of the first output wheel can be achieved, and there is no impact feeling during the speed change process, which can improve the riding experience of the rider.

[0029] In addition, in this power system, the speed-regulating transmission mechanism adopts a speed-regulating planetary gear mechanism, and the output power of the power-assisted transmission mechanism is transmitted to the speed-regulating planetary gear mechanism. At the same time, in cooperation with the driving force of the speed-regulating motor on the speed-regulating planetary gear mechanism, the first output wheel connected to the output end of the speed-regulating planetary gear mechanism can achieve stepless speed change, improving the riding experience of the rider.

[0030] When the speed-regulating planetary gear mechanism adopts a solution of two or more sets of speed-regulating planetary gear mechanisms, the overall maximum transmission ratio of the system can be further improved, and the phenomenon of slipping due to excessive pedaling force of the rider can be avoided.

[0031] In addition, in this power system, the power-assisted transmission mechanism adopts a power-assisted planetary gear mechanism. By using the power-assisted planetary gear mechanism as the transmission mechanism of the power-assisted motor, the effect of speed reduction and torque increase can be achieved, providing a greater auxiliary force. Furthermore, the climbing power of the electric-assisted bicycle can be improved, enabling the electric-assisted bicycle to adapt to more complex road conditions and improving the riding experience of the rider.

[0032] When the power-assisting planetary gear mechanism adopts two or more sets of planetary gear sets, the speed reduction and torque increase effect of the power-assisting planetary gear mechanism can be improved, further improving the climbing power of the electric-assisted bicycle, enabling the electric-assisted bicycle to adapt to more complex road conditions and improving the rider's riding experience.

[0033] In addition, in this power system, a second output wheel is set on the middle axis, and the second output wheel is connected to the rear wheel transmission. During non-powered riding, the power-assisted motor and the speed-regulating motor do not work, and the rider's pedaling force is directly transmitted to the rear wheel through the second output wheel. During this process, the first output wheel idles, which can achieve a riding experience comparable to that of a traditional bicycle.

[0034] In addition, in this power system, since the human power output driving wheel and the central shaft are connected through the first clutch, the setting of the first clutch makes it easy to transmit human power through the central shaft to the speed regulating ring gear of the speed regulating planetary gear mechanism. On the other hand, it makes it easy for the rider to step on the pedals in the opposite direction without resistance at the beginning of riding, so as to adjust the pedal position and then adjust the force angle, thereby improving the riding experience.

[0035] In addition, in this power system, by setting a second output wheel to be connected to the middle shaft, and then the second output wheel to be connected to the rear wheel, human power can be transmitted to the second output wheel through the middle shaft and then to the rear wheel in non-power-assisted conditions without passing through the first output wheel, thereby achieving a riding experience equivalent to that of a transmission bicycle.

[0036] When the second output wheel and the bottom bracket are connected via the second clutch, the second clutch allows the rider to pedal in the opposite direction without resistance during riding, so that the rider can adjust the position of the pedals at the beginning of riding, and then adjust the force angle, thereby improving the riding experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following is a brief introduction to the drawings required for use in the description of the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the contents of the embodiments of the present application and these drawings without any creative work.

[0038] Figure 1 It is a schematic structural diagram of the electric-assisted bicycle provided in an embodiment of the present application.

[0039] Figure 2 It is a structural diagram of the power system of the first example provided in the embodiment of the present application.

[0040] Figure 3It is a schematic structural diagram of the power system of the second example provided by the embodiments of the present application.

[0041] Figure 4 It is a schematic structural diagram of the power system of the third example provided by the embodiments of the present application.

[0042] Figure 5 It is a schematic structural diagram of the power system of the fourth example provided by the embodiments of the present application.

[0043] Figure 6 is Figure 2 and Figure 3 a schematic structural diagram of the assisted planetary gear mechanism in the example.

[0044] Figure 7 is Figure 4 and Figure 5 a schematic structural diagram of the assisted planetary gear mechanism in the example.

[0045] Figure 8 It is a schematic diagram showing the relationship between the pedaling frequency and the vehicle speed under different conditions provided by the embodiments of the present application.

[0046] Reference numerals:

[0047] 100, vehicle body; 200, front wheel; 300, rear wheel; 400, crank; 500, pedal;

[0048] 1, bottom bracket;

[0049] 21, assisted motor; 22, assisted planetary gear mechanism; 221, assisted sun gear; 222, assisted planet gear; 2221, planet gear carrier; 2222, planet gear set; 2222a, first planet gear set; 2222b, second planet gear set; 2223, connecting shaft; 223, assisted ring gear; 23, assisted output driving wheel;

[0050] 31, speed regulation motor; 32, speed regulation planetary gear mechanism; 321, speed regulation sun gear; 322, speed regulation planet gear; 323, speed regulation ring gear; 33, assisted output driven wheel;

[0051] 4, first output wheel;

[0052] 51, first manual transmission mechanism; 511, manual output driving wheel; 512, manual output driven wheel; 513, force sensor; 514, first clutch; 52, second manual transmission mechanism; 521, second output wheel; 522, second clutch. Detailed implementation manners

[0053] Before explaining in detail any embodiment of the present application, it should be understood that the present application is not limited to the structural details and component arrangements set forth in the following description or shown in the above drawings.

[0054] In this application, the terms "comprise", "include", "have" or any other variant thereof are intended to cover non-exclusive inclusion, such that a process, method, article or apparatus comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or apparatus. Without further limitation, an element defined by the statement "comprising one..." does not exclude the presence of additional identical elements in the process, method, article or apparatus comprising that element.

[0055] In this application, the term "and / or" describes the relationship between associated objects and indicates that three relationships can exist. For example, A and / or B can represent three cases: A exists alone, A and B exist simultaneously, and B exists alone. Additionally, in this application, the character " / " generally indicates that the associated objects before and after are in an "and / or" relationship.

[0056] In this application, the terms "connect", "combine", "couple", "mount" can be direct connection, combination, coupling or mounting, or can be indirect connection, combination, coupling or mounting. Among them, by way of example, direct connection means that two parts or components are connected together without the need for an intermediate member, and indirect connection means that two parts or components are respectively connected to at least one intermediate member, and these two parts or components are connected through the intermediate member. In addition, "connect" and "couple" are not limited to physical or mechanical connection or coupling, and can include electrical connection or coupling.

[0057] In this application, those of ordinary skill in the art will understand that relative terms used in connection with a quantity or condition (such as "about", "approximately", "substantially", etc.) are intended to include the stated value and have the meaning indicated by the context. For example, such relative terms include at least the degree of error associated with the measurement of a particular value, tolerances due to manufacturing, assembly, use, etc. associated with a particular value. Such terms should also be considered to disclose a range defined by the absolute values of two endpoints. Relative terms may refer to a plus or minus a certain percentage (such as 1%, 5%, 10% or more) of the indicated value. A numerical value without the use of a relative term should also be disclosed as a particular value with a tolerance. In addition, "substantially" when expressing a relative angular positional relationship (such as substantially parallel, substantially perpendicular) may refer to a plus or minus a certain number of degrees (such as 1 degree, 5 degrees, 10 degrees or more) based on the indicated angle.

[0058] In this application, those of ordinary skill in the art will understand that the functions performed by a component can be performed by one component, multiple components, one part, or multiple parts. Similarly, the functions performed by a part can also be performed by one part, one component, or a combination of multiple parts.

[0059] In this application, the directional terms such as "upper", "lower", "left", "right", "front", and "rear" are described based on the orientation and positional relationship shown in the drawings, and should not be construed as a limitation on the embodiments of this application. In addition, in the context, it should also be understood that when it is mentioned that one component is connected "above" or "below" another component, it can not only be directly connected "above" or "below" another component, but also be indirectly connected "above" or "below" another component through an intermediate component. It should also be understood that directional terms such as the upper side, lower side, left side, right side, front side, and rear side not only represent the positive direction, but can also be understood as the side direction. For example, the lower side can include directly below, lower left, lower right, lower front, and lower rear, etc.

[0060] As Figure 1 shown, this application provides an electrically assisted bicycle, including a vehicle body 100, a front wheel 200, a rear wheel 300, a crank 400, a pedal 500, and a power system. The front wheel 200 and the rear wheel 300 are respectively rotatably mounted on the vehicle body 100. The power system is mounted on the vehicle body 100, and one end of the crank 400 is connected to the power system, and the other end of the crank 400 is connected to the pedal 500. When the rider steps on the pedal 500, the power system provides corresponding auxiliary power according to the stepping force of the rider to cooperate with human power to drive the rear wheel 300 to rotate, and then drive the assisted bicycle to move forward.

[0061] It should be noted that Figure 1 In the shown electrically assisted bicycle, the assembly methods of both the front wheel 200 and the rear wheel 300 with the vehicle body 100 and the assembly method of the crank 400 with the pedal 500 can both adopt common assembly methods in the prior art, and will not be elaborated here.

[0062] In the related art, the single-motor power system can provide auxiliary power, but it has no continuously variable transmission function and cannot meet the needs of riders for high-performance assisted bicycles. Although the dual-motor power system can provide auxiliary power and speed change, it often adopts a three-center-axis scheme, which has a large structural size, high requirements for the size of the vehicle body 100, and there will be a sense of impact during the gear shifting and speed change process, resulting in a poor riding experience. In addition, due to the limited speed regulation ability of the power system, when the rider steps on the pedal with too much force during riding, it is easy to have a situation of pedaling in the air and slipping, which affects riding safety.

[0063] Based on the above situation, this application provides a power system for an electrically assisted bicycle, as Figures 2 to 5As shown, the power system adopts a dual-motor and dual-axis drive, with boosting and stepless speed change functions. While meeting the high-performance requirements of the bicycle, it not only has a compact structure and small space occupancy, but also can improve the speed regulation ability of the system and avoid the phenomenon of slipping due to excessive pedaling force of the rider.

[0064] In addition, for the convenience of understanding, the "transmission connection between two components" mentioned in the following description of this specification means that when one component moves, it can drive the other component to move. The form of transmission connection can be a fixed connection between the two components; or a transmission connection between the two components by means of a keyway, such as the transmission connection between the motor output shaft and the transmission shaft; or a transmission connection between the two components by means of an idler wheel, such as the transmission connection between two gears through an idler wheel; or a transmission connection between the two components by means of a synchronous belt, such as the transmission connection between two belt pulleys through a synchronous belt; or a transmission connection between the two components by means of a chain, such as the transmission connection between two sprockets or chainrings through a chain. It can be understood that the form of transmission connection between two components is not limited to the above examples, and any connection method that can achieve the movement of one component driving the other component is acceptable, and no further examples will be given here.

[0065] Continue as Figure 2 As shown, the power system includes a housing (not shown in the figure), a central shaft 1, an electric boosting device, an electric speed regulation device, and a first output wheel 4. Among them, the central shaft 1 is rotatably installed in the housing and is used for fixedly connecting with the crank 400; both the electric boosting device and the electric speed regulation device are at least partially installed in the housing. The electric boosting device includes a boosting motor 21 and a boosting transmission mechanism. The output end of the boosting motor 21 is in transmission connection with the input end of the boosting transmission mechanism, and the rotation axis of the input end of the boosting transmission mechanism coincides with the rotation axis of the central shaft 1; the electric speed regulation device includes a speed regulation motor 31 and a speed regulation transmission mechanism. The speed regulation transmission mechanism has two input ends. Its first input end is in transmission connection with the output end of the speed regulation motor 31, and the rotation axis of the output end of the speed regulation motor 31 is parallel to the rotation axis of the output end of the boosting motor 21. The second input end of the speed regulation transmission mechanism is in transmission connection with the output end of the boosting transmission mechanism, and the output end of the speed regulation transmission mechanism is in transmission connection with the first output wheel 4, and the first output wheel 4 is in transmission connection with the rear wheel 300.

[0066] The power system for the electric-assisted bicycle uses an assist transmission mechanism in cooperation with an assist motor 21 to achieve the effect of speed reduction and torque increase, providing auxiliary force for the rider, reducing the riding difficulty of the rider, and alleviating the riding fatigue of the rider. By setting the rotation axis of the input end of the assist transmission mechanism to coincide with the rotation axis of the central shaft 1, dual-motor and dual-axis drive can be achieved, with a more compact structure and less space occupied. The speed regulation motor 31 provides a power input for the speed regulation transmission mechanism, and human power and the assist transmission mechanism provide another power input for the speed regulation transmission mechanism, enabling dynamic adjustment of the rotational speed of the output end of the speed regulation transmission mechanism, thereby changing the transmission ratio from the central shaft to the first output wheel and achieving the effect of stepless speed change.

[0067] In addition, the power system further includes a human power transmission device. The human power transmission device includes a force sensor 513 and a first human power transmission mechanism 51. The first human power transmission mechanism 51 is used for transmission connection between the central shaft 1 and the speed regulation transmission mechanism. The force sensor 513 is installed on the first human power transmission mechanism 51 and is used for detecting the pedaling frequency and pedaling force of the rider, so as to, in the assist mode, the electric speed regulation device and the electric assist device cooperate with the force sensor 513 to provide electric assist and transmission ratio that are more matched with human power.

[0068] The human power transmission device further includes a second human power transmission mechanism 52. The second human power transmission mechanism 52 is used for transmission connection between the central shaft 1 and the rear wheel 300 to transmit human power to the rear wheel 300 and achieve force transmission in the non-assist mode.

[0069] The working principle of the human power transmission device is as follows: The force sensor 513 and the first human power transmission mechanism 51 cooperate with the speed regulation transmission mechanism. The force sensor 513 detects the pedaling frequency and pedaling force of the rider. The electric assist device and the electric speed regulation device provide electric assist and transmission ratio that are matched with human power according to the monitoring data of the force sensor 513. Among them, the adapted electric assist can reduce the riding difficulty of the rider and alleviate the fatigue of the rider, and the adapted transmission ratio (the transmission ratio from the central shaft to the first output wheel) can achieve stepless speed change, avoiding shift shock and enhancing the riding experience. In addition, the second human power transmission mechanism 52 cooperates with the rear wheel 300 to achieve human-powered riding in the non-assist mode, providing the rider with a riding feeling equivalent to that of a traditional bicycle. Compared with other electric-assisted bicycles in the related art, when riding in the non-assist mode, human power does not need to drive the relevant transmission mechanisms of the electric drive device, so it is more labor-saving.

[0070] The first manual transmission mechanism 51 includes a manual output driving wheel 511 and a manual output driven wheel 512 that is drivingly connected to the manual output driving wheel 511. The manual output driving wheel 511 is sleeved outside the central shaft 1 through a first clutch 514, and the manual output driven wheel 512 is drivingly connected to the speed regulation transmission mechanism, so as to transmit the power of the central shaft 1 to the speed regulation transmission mechanism. Through the arrangement of the first manual transmission mechanism 51, when riding in the assist mode, the manual force is transmitted from the central shaft 1 to the manual output driving wheel 511, and drives the manual output driven wheel 512 to rotate, and then can drive the relevant transmission mechanisms of the speed regulation transmission mechanism to move. At this time, the force sensor 513 can accurately sense the riding state of the rider in the assist mode, obtain the pedal frequency and pedaling force that are more in line with the actual riding state of the rider, which is convenient for the electric assist device to provide electric assist that is more matched with the pedaling force, and at the same time is convenient for the electric speed regulation device to provide a transmission ratio that is more matched with the pedal frequency, improving the riding experience of the rider.

[0071] In one embodiment, the manual output driving wheel 511 and the manual output driven wheel 512 can be drivingly connected through a chain or a synchronous belt or an idler wheel. For example, when both the manual output driving wheel 511 and the manual output driven wheel 512 are sprockets, the two are drivingly connected through a chain; when both the manual output driving wheel 511 and the manual output driven wheel 512 are belt wheels, the two are drivingly connected through a synchronous belt; when both the manual output driving wheel 511 and the manual output driven wheel 512 are gears, the two are drivingly connected through an idler wheel; specifically, it can be designed according to needs, and no further examples will be given here.

[0072] The second manual transmission mechanism 52 includes a second output wheel 521. The second output wheel 521 is sleeved outside the central shaft 1 through a second clutch 522, and the second output wheel 521 is used to be drivingly connected to the rear wheel 300 of the bicycle. When riding in the non-assist mode, both the assist motor 21 and the speed regulation motor 31 do not work. The pedaling force of the rider drives the rear wheel 300 to rotate through the central shaft 1, the second clutch 522, and the second output wheel 521, and a riding experience equivalent to that of a traditional bicycle can be achieved. Compared with other electric assist bicycles in the related art, when riding in the non-assist mode, the manual force does not need to drive the relevant transmission mechanisms of the electric drive device, so it is more labor-saving.

[0073] Since the second output wheel 521 and the central shaft 1 are realized through the second clutch 522, through the arrangement of the second clutch 522, not only can the power of the central shaft 1 be transmitted to the second output wheel 521, and then the power is transmitted from the second output wheel 521 to the rear wheel to achieve a riding experience equivalent to that of a traditional bicycle in the non-assist mode; but also allows the rider to reverse pedal the foot pedal without resistance during the riding process, so as to facilitate the rider to adjust the position of the foot pedal at the start of riding, and then adjust the force application angle, improving the riding experience.

[0074] In one embodiment, both the first output wheel 4 and the second output wheel 521 are chainrings, and both are drivingly connected to the rear wheel 300 through a chain. In another embodiment, both the first output wheel 4 and the second output wheel 521 are belt pulleys, and both are drivingly connected to the rear wheel 300 through a timing belt.

[0075] Referring to Figures 2 to 5 as shown, Figures 2 to 5 in the examples shown, the structures of the manual transmission devices are basically the same, and the main differences between the examples are that: the structures of the power assist transmission mechanism and the speed regulation transmission mechanism are different. For ease of understanding, the following will combine Figures 2 to 5 to introduce the specific implementation schemes of the power assist transmission mechanism and the speed regulation transmission mechanism.

[0076] The power assist transmission mechanism includes a power assist planetary gear mechanism 22 and a power assist output driving wheel 23. The output end of the power assist motor 21 is drivingly connected to the input end of the power assist planetary gear mechanism 22, the output end of the power assist planetary gear mechanism 22 is drivingly connected to the power assist output driving wheel 23, and the power assist output driving wheel 23 is drivingly connected to the second input end of the speed regulation transmission mechanism. Through the setting of the power assist planetary gear mechanism 22, the effect of reducing the speed and increasing the torque of the power assist motor 21 can be achieved, and then a greater torque is transmitted to the speed regulation transmission mechanism through the power assist output driving wheel 23, so that the speed regulation transmission mechanism can provide sufficient power for the first output wheel 4, which can reduce the riding difficulty of the rider and relieve the fatigue of the rider.

[0077] The power assist planetary gear mechanism 22 includes a power assist sun gear 221, power assist planet gears 222 and a power assist ring gear 223. The power assist sun gear 221, as the input end of the power assist planetary gear mechanism 22, is drivingly connected to the output end of the power assist motor 21; the power assist planet gears 222, as the output end of the power assist planetary gear mechanism 22, are drivingly connected to the power assist output driving wheel 23; the power assist ring gear 223 is fixedly connected to the housing. According to the planetary gear transmission principle, when the power assist ring gear 223 is fixed, the power assist sun gear 221 rotates at a certain speed under the drive of the power assist motor 21, and then under the meshing action of the power assist sun gear 221, the power assist planet gears 222 and the power assist ring gear 223, the power assist planet gears 222 can also rotate at a certain speed. Based on this transmission principle, by reasonably designing the dimensions and number of teeth of the power assist sun gear 221, the power assist planet gears 222 and the power assist ring gear 223, the effect of reducing the speed and increasing the torque of the power assist motor 21 can be achieved.

[0078] In Figure 2 and Figure 3 the examples shown, and in combination with Figure 6As shown, the assist planetary gear 222 includes a planetary gear carrier 2221 and a planetary gear set 2222. Among them, the planetary gear carrier 2221 is in coaxial transmission connection with the assist output driving wheel 23. For example, the planetary gear carrier 2221 is fixedly connected coaxially with the assist output driving wheel 23 or in coaxial keyway transmission connection; the number of the planetary gear sets 2222 is one group, and the planetary gear set 2222 is simultaneously meshed with the assist sun gear 221 and the assist ring gear 223. Exemplarily, at least three planetary gears are included in one group of planetary gear sets 2222. At least three planetary gears are evenly spaced along the same circumference with the rotation center of the assist sun gear 221 as the center of the circle, and the three planetary gears are rotatably mounted on the planetary gear carrier.

[0079] In Figure 4 and Figure 5 In the example shown, and in combination with Figure 7 As shown, the assist planetary gear 222 includes a planetary gear carrier 2221, a planetary gear set 2222 and a connecting shaft 2223. Among them, the number of the planetary gear sets 2222 is two groups, which are respectively denoted as the first planetary gear set 2222a and the second planetary gear set 2222b. The planetary gear carrier 2221 is in coaxial transmission connection with the assist output driving wheel 23. For example, the planetary gear carrier 2221 is fixedly connected coaxially with the assist output driving wheel 23 or in coaxial keyway transmission connection; at least three planetary gears are included in both the first planetary gear set 2222a and the second planetary gear set 2222b. At least three planetary gears are evenly spaced along the same circumference with the rotation center of the assist sun gear 221 as the center of the circle, and the number of the connecting shafts 2223 is the same as the number of the planetary gears in each group of planetary gear sets 2222. Further, the corresponding planetary gears in the first planetary gear set 2222a and the second planetary gear set 2222b are respectively connected to both ends of the corresponding connecting shaft 2223, where the first planetary gear set 2222a is meshed with the assist sun gear 221, and the second planetary gear set 2222b is meshed with the assist ring gear 223. With such a setting, the reduction of speed and increase of torque effect of the assist planetary gear mechanism 22 can be further improved by reasonably designing the sizes and tooth numbers of the planetary gears in the two groups of planetary gear sets 2222.

[0080] In summary, it can be seen that the reduction of speed and increase of torque effect of the assist planetary gear mechanism 22 with two groups of planetary gear sets 2222 is better than that of the assist planetary gear mechanism 22 with one group of planetary gear sets 2222, and it can provide a greater torque. Furthermore, the climbing power of the electric assist bicycle can be improved, so that the electric assist bicycle can adapt to more complex road conditions and enhance the riding experience of the rider. And the assist planetary gear mechanism 22 with one group of planetary gear sets 2222 has the advantages of small volume and light weight, and can be applied to models with low requirements for assist torque and good riding conditions, such as electric assist bicycles for urban commuting.

[0081] Figure 2 Compared with Figure 3The differences between the illustrated examples and Figure 4 and Figure 5 the differences between the illustrated examples all lie in that the structures of the speed-regulating drive mechanisms are different.

[0082] The speed-regulating drive mechanism includes a speed-regulating planetary gear mechanism 32 and a power-assisted output driven wheel 33. The output end of the power-assisted transmission mechanism (i.e., the power-assisted output driving wheel 23) is in transmission connection with the power-assisted output driven wheel 33; the speed-regulating planetary gear mechanism 32 has two input ends. Its first input end is in transmission connection with the output end of the speed-regulating motor 31, the second input end is connected to the power-assisted output driven wheel 33, and the output end of the speed-regulating planetary gear mechanism 32 is in transmission connection with the first output wheel 4.

[0083] In an embodiment, the power-assisted output driving wheel 23 and the power-assisted output driven wheel 33 can be in transmission connection through a chain or a synchronous belt or an idler gear. For example, when both the power-assisted output driving wheel 23 and the power-assisted output driven wheel 33 are sprockets, the two are in transmission connection through a chain; when both the power-assisted output driving wheel 23 and the power-assisted output driven wheel 33 are belt pulleys, the two are in transmission connection through a synchronous belt; when both the power-assisted output driving wheel 23 and the power-assisted output driven wheel 33 are gears, the two are in transmission connection through an idler gear; specifically, it can be designed according to needs, and no further examples will be given here.

[0084] Figure 2 and Figure 4 In the illustrated example, the number of the speed-regulating planetary gear mechanisms 32 is one group, and the speed-regulating planetary gear mechanism 32 includes a speed-regulating sun gear 321, speed-regulating planet gears 322 and a speed-regulating gear ring 323; the speed-regulating sun gear 321 serves as the first input end of the speed-regulating planetary gear mechanism 32 and is in transmission connection with the output end of the speed-regulating motor 31, the speed-regulating gear ring 323 serves as the second input end of the speed-regulating planetary gear mechanism 32 and is in transmission connection with the power-assisted output driven wheel 33; the speed-regulating planet gears 322 serve as the output end of the speed-regulating planetary gear mechanism 32 and are in transmission connection with the first output wheel 4. With such a setting, the speed of the first output wheel 4 can be regulated by cooperating with the input of the speed-regulating motor 31 and the input of the electric power-assisted device through one group of speed-regulating planetary gear mechanisms 32, so that the first output wheel 4 realizes stepless speed change.

[0085] It should be noted that the first input end, i.e., the speed-regulating sun gear 321, of the speed-regulating planetary gear mechanism 32 can have one power input, or two or more power inputs. For example Figure 2 one power input in the example is the speed-regulating motor 31. Specifically, it can be designed according to needs and is not limited here; the second input end, i.e., the speed-regulating gear ring 323, of the speed-regulating planetary gear mechanism 32 can have one power input, or two or more power inputs. For example Figure 2The two power inputs in the example are respectively the power input by the assisted output driven wheel 33 and the power input by the human power output driven wheel 512, which can be specifically designed according to needs and are not limited here.

[0086] To better understand the differences among continuously variable transmission, shift transmission, and non-variable speed functions, refer to Figure 8 the schematic diagram showing the relationship between pedal frequency and vehicle speed under different conditions as shown. For the case of non-variable speed, in order to continuously increase the vehicle speed, the cyclist needs to continuously increase the pedal frequency, that is, the pedal frequency and the vehicle speed are in a linear relationship under the non-variable speed function. However, the cyclist's pedal frequency is limited, so the vehicle speed of the bicycle cannot be increased infinitely. For the case of shift transmission, the cyclist can change the relationship between the pedal frequency and the vehicle speed by shifting gears to achieve an increase in vehicle speed while the pedal frequency decreases or remains unchanged. However, the shift impact is relatively obvious and the riding experience is not good. For the case of continuously variable transmission, when the vehicle speed is getting faster and faster, the speed regulating planetary gear mechanism 32 is driven by the speed regulating motor 31 to change the transmission ratio of the system, making the cyclist's pedal frequency more stable and enabling continuously variable transmission without shift impact, providing a good riding experience.

[0087] Figure 3 and Figure 5 In the example shown, the number of speed regulating planetary gear mechanisms 32 is two groups. Each group of speed regulating planetary gear mechanisms 32 includes a speed regulating sun gear 321, a speed regulating planet gear 322, and a speed regulating ring gear 323. The two groups of speed regulating planetary gear mechanisms 32 are arranged in sequence from the direction where the speed regulating motor 31 is located to the direction of the first output wheel 4. And the speed regulating sun gear 321 of the first speed regulating planetary gear mechanism 32 is used as the first input end and is in transmission connection with the output end of the speed regulating motor 31. The speed regulating ring gear 323 of the second speed regulating planetary gear mechanism 32 is used as the second input end and is in transmission connection with the assisted output driven wheel 33. The speed regulating planet gear 322 of the second speed regulating planetary gear mechanism 32 is used as the output end and is in transmission connection with the first output wheel 4. By setting two groups of speed regulating planetary gear mechanisms 32, compared with one group of speed regulating planetary gear mechanisms 32, the maximum transmission ratio of the system can be increased, and the phenomenon of slipping due to excessive pedaling force of the cyclist can be avoided.

[0088] It can be understood that the number of speed-regulating planetary gear mechanisms 32 can also be three or more. The speed-regulating planetary gear mechanisms 32 are arranged in sequence from the direction where the speed-regulating motor 31 is located to the direction where the first output wheel 4 is located. The speed-regulating sun gear 321 of the first speed-regulating planetary gear mechanism 32 is used as the first input end and is drivingly connected to the output end of the speed-regulating motor 31. The speed-regulating ring gear 323 of the last speed-regulating planetary gear mechanism 32 is used as the second input end and is drivingly connected to the assisted output driven wheel 33. The speed-regulating planet gear 322 of the last speed-regulating planetary gear mechanism 32 is used as the output end and is drivingly connected to the first output wheel 4. The more the number of speed-regulating planetary gear mechanisms 32, the greater the maximum transmission ratio that can be provided, thereby avoiding the phenomenon of slipping due to excessive pedaling force by the rider.

[0089] It should be noted that in Figure 3 the shown example, the speed-regulating ring gears 323 of the two speed-regulating planetary gear mechanisms 32 are coaxially and fixedly connected, that is, the power inputs of the speed-regulating ring gears 323 of the two speed-regulating planetary gear mechanisms 32 are the same, both from the power input by the assisted output driven wheel 33 and the power input by the manual output driven wheel 512. When the number of speed-regulating planetary gear mechanisms 32 is three or more, the speed-regulating ring gears 323 of all speed-regulating planetary gear mechanisms 32 can be coaxially and fixedly connected. Of course, in other cases, when the number of speed-regulating planetary gear mechanisms 32 is three or more, the speed-regulating ring gears 323 of each speed-regulating planetary gear mechanism 32 can also be independently arranged. Among them, the speed-regulating ring gear 323 of the last speed-regulating planetary gear mechanism 32 is used as the second input end and is connected to the assisted output driven wheel 33 and the manual output driven wheel 512, respectively receiving the power from the assisted output driving wheel 23 and the manual output driving wheel 511.

[0090] Based on the scheme of this speed-regulating transmission mechanism, the manual output driven wheel 512 of the first manual transmission mechanism 51 is coaxially and fixedly connected to the assisted output driven wheel 33 and is also coaxially and fixedly connected to the speed-regulating ring gear 323 of the last speed-regulating planetary gear mechanism 32. The power of the central shaft 1 is transmitted to the assisted output driven wheel 33 through the manual output driving wheel 511 and the manual output driven wheel 512, that is, the pedaling force can be used as an input power of the second input end (i.e., the speed-regulating ring gear 323) of the speed-regulating planetary gear mechanism 32, and cooperate with the other input power transmitted from the assisted output driving wheel 23 to the second input end (i.e., the speed-regulating ring gear 323) of the speed-regulating planetary gear mechanism 32 through the assisted output driven wheel 33. The two input powers jointly determine the rotational speed of the speed-regulating ring gear 323 of the speed-regulating planetary gear mechanism 32, and then cooperate with the rotational speed of the speed-regulating sun gear 321 controlled by the speed-regulating motor 31 to finally determine the output rotational speed of the speed-regulating planet gear 322, and further determine the output rotational speed of the first output wheel 4.

[0091] Since the manual output driving wheel 511 is connected to the central shaft 1 through the first clutch 514, on the one hand, the manual force can be conveniently transmitted to the speed-regulating gear ring 323 of the speed-regulating planetary gear mechanism 32 through the central shaft 1 by setting the first clutch 514. On the other hand, it is convenient for the rider to step on the pedals in the reverse direction without resistance at the start of riding to adjust the pedal position, and then adjust the force application angle to improve the riding experience.

[0092] The present application also provides an electric-assisted bicycle applying the above power system. The electric-assisted bicycle has a power-assisted riding mode and a non-power-assisted riding mode.

[0093] Next, in combination with Figure 5 the examples shown below, the operating states of the components of the power system in the power-assisted riding mode and the non-power-assisted riding mode will be described respectively.

[0094] 1) In the power-assisted riding mode: The first clutch 514 remains in a wedged state, the second clutch 522 is disengaged, both the power-assisted motor 21 and the speed-regulating motor 31 are started, and the first output wheel 4 serves as the output component of the power system to transmit power to the rear wheel 300.

[0095] On the one hand, in order to make it easier and more labor-saving for the rider to obtain a better riding experience, the power system obtains the riding data of the rider according to the information such as vehicle speed, pedal frequency, and pedaling force collected by the force sensor 513, and judges the riding state of the rider at this time; the power-assisted motor 21 outputs auxiliary power according to the riding state of the rider, and the auxiliary power is transmitted to the speed-regulating transmission mechanism through the power-assisted transmission mechanism and finally transmitted to the first output wheel 4, so as to provide auxiliary power for the rider and reduce the riding difficulty of the rider.

[0096] On the other hand, the power system adjusts the output speed of the speed-regulating motor 31 according to the information such as vehicle speed, pedal frequency, and pedaling force collected by the force sensor 513, and adjusts the speed of the first output wheel 4 through the speed-regulating planetary gear mechanism 32, and then changes the transmission ratio between the first output wheel 4 and the central shaft 1. It can not only achieve the effect of stepless speed change, but also reduce the impact and sudden change of speed caused by adding and subtracting mechanical gears during the speed change process compared with the traditional shift speed regulation, improving the riding experience of the rider; in addition, the overall maximum transmission ratio of the system can be increased through the two groups of speed-regulating planetary gear mechanisms 32 to avoid the phenomenon of slipping due to excessive pedaling force of the rider.

[0097] 2) In the non-power-assisted mode: Both the first clutch 514 and the second clutch 522 remain in a wedged state, both the power-assisted motor 21 and the speed-regulating motor 31 are not started, and the second output wheel 521 serves as the output component of the power system to transmit power to the rear wheel 300, where the first output wheel 4 is in an idling state.

[0098] During cycling, the cyclist pedals the pedal 500, rotates the bottom bracket 1 through the crank 400, and then drives the second output wheel 521 to rotate by the bottom bracket 1. Finally, the power is transmitted to the rear wheel 300 to achieve a cycling experience equivalent to that of a traditional bicycle.

[0099] It should be noted that in some electric-assisted bicycles, in addition to the above-mentioned assisted cycling mode (relying on human power and electric assistance), the assisted cycling mode of the electric-assisted bicycle also includes a twist-grip assist mode (relying only on electric assistance). The twist-grip assist mode means that the cyclist controls the corresponding auxiliary power output by the assist motor 21 by rotating the handlebar of the electric-assisted bicycle, rather than relying on the information such as vehicle speed, pedal frequency, and pedaling force collected by the force sensor 513 to control the assist motor 21. At this time, the power transmitted from the human power output driving wheel 511 to the human power output driven wheel 512 can be disconnected, that is, the power transmitted from the human power to the speed regulation transmission mechanism is disconnected. The cyclist controls the assist ability and speed regulation ability of the electric assist device and the electric speed regulation device through the twist grip.

[0100] The above shows and describes the basic principles, main features, and advantages of the present application. Those skilled in the art should understand that the above embodiments do not limit the present application in any form. Any technical solution obtained by using equivalent replacement or equivalent transformation falls within the protection scope of the present application.

Claims

1. A power system for an electrically assisted bicycle, characterized in that, Comprising: A housing; A central shaft (1) rotatably mounted on the housing, and the central shaft (1) is used for fixedly connecting with a crank (400) of a bicycle; An electric assist device, including an assist motor (21) and an assist transmission mechanism, an output end of the assist motor (21) is coaxially and drivably connected with an input end of the assist transmission mechanism, and a rotation axis of an input end of the assist motor (21) coincides with a rotation axis of the central shaft (1); An electric speed regulation device, including a speed regulation motor (31) and a speed regulation transmission mechanism, the speed regulation transmission mechanism has two input ends, a first input end thereof is coaxially and drivably connected with an output end of the speed regulation motor (31), and a second input end thereof is drivably connected with an output end of the assist transmission mechanism; a rotation axis of an output end of the speed regulation motor (31) is parallel to a rotation axis of the central shaft (1); A first output wheel (4) drivably connected with an output end of the speed regulation transmission mechanism, and the first output wheel (4) is used for drivably connecting with a rear wheel (300) of a bicycle.

2. The power system for an electrically assisted bicycle according to claim 1, characterized in that, The assist transmission mechanism includes an assist planetary gear mechanism (22) and an assist output driving wheel (23), an output end of the assist motor (21) is drivably connected with an input end of the assist planetary gear mechanism (22), an output end of the assist planetary gear mechanism (22) is drivably connected with the assist output driving wheel (23), and the assist output driving wheel (23) is drivably connected with a second input end of the speed regulation transmission mechanism.

3. The power system for an electrically assisted bicycle according to claim 2, characterized in that, The assist planetary gear mechanism (22) includes an assist sun gear (221), assist planet gears (222) and an assist ring gear (223), the assist sun gear (221) serves as an input end of the assist planetary gear mechanism (22) and is coaxially and drivably connected with an output end of the assist motor (21); the assist planet gears (222) serve as an output end of the assist planetary gear mechanism (22) and are coaxially and drivably connected with the assist output driving wheel (23); the assist ring gear (223) is fixedly connected with the housing.

4. The power system for an electrically assisted bicycle according to claim 3, wherein, The assist planet gears (222) include a planet gear carrier (2221) and a planet gear set (2222), and the planet gear carrier (2221) is coaxially and drivably connected with the assist output driving wheel (23); When the number of the planet gear sets (2222) is one group, the planet gear set (2222) is simultaneously meshed with the assist sun gear (221) and the assist ring gear (223); When the number of the planetary gear sets (2222) is two, the assisting planetary gear (222) further includes a connecting shaft (2223) rotatably connected to the planetary gear carrier (2221). Both of the two planetary gear sets (2222) include planetary gears, and the number of the planetary gears in each planetary gear set (2222) is the same as that of the connecting shafts (2223). The corresponding planetary gears in the two planetary gear sets (2222) are respectively connected to two ends of the corresponding connecting shaft (2223). One of the planetary gear sets (2222a) meshes with the assisting sun gear (221), and the other planetary gear set (2222b) meshes with the assisting ring gear (223).

5. The power system for an electrically assisted bicycle according to any one of claims 2-4, characterized in that, The speed regulation transmission mechanism includes a speed regulation planetary gear mechanism (32) and an assisting output driven wheel (33). The output end of the assisting transmission mechanism is in transmission connection with the assisting output driven wheel (33). The speed regulation planetary gear mechanism (32) has two input ends. Its first input end is in transmission connection with the output end of the speed regulation motor (31), and the second input end is connected to the assisting output driven wheel (33). The output end of the speed regulation planetary gear mechanism (32) is in transmission connection with the first output wheel (4).

6. The power system for an electrically assisted bicycle according to claim 5, wherein, The number of the speed regulation planetary gear mechanisms (32) is at least one. Each speed regulation planetary gear mechanism (32) includes a speed regulation sun gear (321), a speed regulation planetary gear (322), and a speed regulation ring gear (323). When the number of the speed regulation planetary gear mechanisms (32) is one, the speed regulation sun gear (321) is in coaxial transmission connection with the output end of the speed regulation motor (31), and the speed regulation ring gear (323) is in coaxial transmission connection with the assisting output driven wheel (33). The speed regulation planetary gear (322) serves as the output end of the speed regulation planetary gear mechanism (32) and is in transmission connection with the first output wheel (4). When the number of the speed regulation planetary gear mechanisms (32) is two or more, each speed regulation planetary gear mechanism (32) is arranged in sequence from the direction where the speed regulation motor (31) is located to the direction where the first output wheel (4) is located. The speed regulation sun gear (321) of the first speed regulation planetary gear mechanism (32) is in transmission connection with the output end of the speed regulation motor (31), and the speed regulation ring gear (323) of the last speed regulation planetary gear mechanism (32) is in transmission connection with the assisting output driven wheel (33). The speed regulation planetary gear (322) of the last speed regulation planetary gear mechanism (32) is in transmission connection with the first output wheel (4).

7. The power system for an electrically assisted bicycle according to claim 5, characterized in that, The power system for the electric assist bicycle further includes a human power transmission device. The human power transmission device includes a force sensor (513) and a first human power transmission mechanism (51). The first human power transmission mechanism (51) is used for transmission connection between the middle shaft (1) and the speed regulation transmission mechanism. The force sensor (513) is installed on the first human power transmission mechanism (51) and is used for detecting the pedaling frequency and pedaling force of the rider. The manual transmission device further includes a second manual transmission mechanism (52) for drivingly connecting the central shaft (1) and the rear wheel (300).

8. The power system for an electrically assisted bicycle according to claim 7, characterized in that, The first manual transmission mechanism (51) includes a manual output driving wheel (511) and a manual output driven wheel (512) drivingly connected to the manual output driving wheel (511). The manual output driving wheel (511) is coaxially drivingly connected to the central shaft (1) through a first clutch (514), and the manual output driven wheel (512) is coaxially fixed to the assist output driven wheel (33); and / or The second manual transmission mechanism (52) includes a second output wheel (521) coaxially drivingly connected to the central shaft (1) through a second clutch (522), and the second output wheel (521) is used for drivingly connecting to the rear wheel (300) of the bicycle.

9. The power system for an electric-assisted bicycle according to claim 8, characterized in that, The manual output driving wheel (511) and the manual output driven wheel (512) are drivingly connected by a chain, a timing belt or an idler pulley; and / or The assist output driving wheel (23) and the assist output driven wheel (33) are drivingly connected by a chain, a timing belt or an idler pulley; The second output wheel (521) and the rear wheel (300) are drivingly connected by a chain or a timing belt.

10. An electrically assisted bicycle, characterized in that, It includes a vehicle body (100) and the power system for an electrically assisted bicycle according to any one of claims 1-9, and the power system for an electrically assisted bicycle is installed on the vehicle body (100).

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