Electrically-assisted continuously variable transmission

Abstract

The invention belongs to the technical field of electric power-assisted continuously variable transmissions of bicycles, and particularly relates to an electric power-assisted continuously variable transmission and a control method thereof.The electric power-assisted continuously variable transmission comprises a manpower input component, a planet row assembly, a motor and an output component, the manpower input component is in transmission connection with a planet carrier, and the output component is in transmission connection with a gear ring; the motor drives the sun gear through a first transmission branch provided with a first one-way clutch and drives the output component through a second transmission branch provided with a second one-way clutch, manpower is transmitted to the gear ring in the first rotating direction through a third one-way clutch through a third transmission branch formed by the planet row and is separated in the opposite direction, and the output component is driven by the second one-way clutch. Therefore, the motor can selectively participate in planet row speed regulation or directly drive the output component, manpower can be output through the planet row, and reverse return is blocked. On the premise that the structure is kept compact and closed, continuous and smooth stepless speed change and power coupling output are achieved, dragging loss and impact are reduced, and transmission efficiency and riding comfort are improved.

Description

Technical Field

[0001] This application belongs to the technical field of electric-assisted continuously variable transmissions (CVTs) for bicycles, and more specifically, relates to an electric-assisted CVT. Background Technology

[0002] As people's demands for green travel and energy conservation and environmental protection continue to increase, electric-assisted bicycles (also known as electric-assisted bikes) are gradually becoming a major form of short-distance urban transportation due to their combination of human power and electric assistance. Existing electric-assisted bicycles typically use a mid-mounted motor or hub motor drive system, where the motor assists human power to achieve coordinated output.

[0003] In existing designs, the rear wheel typically uses an external multi-stage freewheel or hub-type derailleur, connected to the front sprocket via a chain, and shifted by a shift fork mechanism. While this type of design provides some gear ratio variation, it suffers from the following drawbacks: 1. The drive chain, freewheel, shift fork, and other components are exposed to the external environment, relying on lubricating oil for smooth operation, which can easily lead to lubricating oil leakage and environmental pollution; 2. Dust and sand easily adhere to the surface of the chain and freewheel, causing increased wear, reduced transmission efficiency, and more frequent maintenance; 3. Mechanical derailleurs have limited gear ratios and inconsistent speed ratio changes, making it difficult to achieve stepless smooth speed adjustment, thus affecting riding comfort.

[0004] To overcome the above problems, existing technologies have proposed integrating the motor and a two-speed mechanical gearbox inside the wheel hub to achieve an electric drive system without exposed chains. Although this solution improves the system's sealing and aesthetics, it typically only has a two-speed mechanical gearbox, limiting its speed ratio adjustment range and making it difficult to adapt to varying operating conditions. Furthermore, the motor operates for extended periods under low-speed, high-load conditions, resulting in lower efficiency.

[0005] In addition, some solutions attempt to improve transmission performance by using a mid-mounted motor in conjunction with a multi-speed hub gearbox or by setting a composite planetary gearbox in the wheel hub. However, these structures generally have the following shortcomings: 1. They are complex in structure, require high manufacturing precision, and have limited assembly space, which is not conducive to lightweight design; 2. The power path is fixed, and there is a lack of flexible allocation of human, motor and wheel inertia under different working conditions.

[0006] In summary, existing technologies, whether employing external chain drive and multi-stage cascades, integrating the motor and two-speed mechanical transmission within the wheel hub, or using a mid-mounted motor with a hub-type or compound planetary gearbox, cannot simultaneously achieve a comprehensive performance that combines a simple and enclosed structure, high transmission efficiency, wide speed ratio range, flexible power distribution, and ease of manufacturing and assembly. Therefore, there is an urgent need for an electric continuously variable transmission (CVT) that can achieve a wide speed ratio, continuously variable speed, adaptive power coupling, and high efficiency and low maintenance characteristics while maintaining a compact and enclosed wheel hub structure. Summary of the Invention

[0007] To address the technical problems of existing external chain drives and multi-stage cascade or hub transmission mechanisms, such as susceptibility to environmental pollution and wear, frequent maintenance, and difficulty in smooth stepless speed regulation due to discrete gears, as well as the limited speed ratio range, low efficiency of motors at low speeds and high loads, and inflexible power distribution of in-hub integrated two-speed solutions, this application provides an electric-assisted continuously variable transmission (CVT). This CVT achieves wide-ratio continuous stepless speed regulation and efficient coordinated output of motor and human power under compact and enclosed conditions within the hub, while reducing reverse drag impact and maintenance requirements.

[0008] On one hand, this application provides an electrically assisted continuously variable transmission, comprising:

[0009] Manual input components;

[0010] A planetary gear assembly, comprising a sun gear, a planet carrier, a ring gear, and several planet gears that mesh with each other;

[0011] Electric motor;

[0012] Output components;

[0013] A first transmission branch connects the output of the motor to the sun gear of the planetary gear assembly, and a first one-way clutch is provided on the first transmission branch. The first one-way clutch is configured to allow only the torque of the motor to be transmitted to the sun gear along the first transmission branch and to disengage when transmitted in the reverse direction.

[0014] The second transmission branch connects the output of the motor to the output component, and the second transmission branch is provided with a second one-way clutch. The second one-way clutch is configured to allow only the torque of the motor to be transmitted to the output component along the second transmission branch and to disengage when transmitted in the reverse direction.

[0015] The third transmission branch is disposed between the human input component and the output component via the planetary gear assembly, and the third transmission branch is provided with a third one-way clutch. The third one-way clutch is configured to allow torque to drive the output component to rotate via the third transmission branch and the ring gear of the planetary gear assembly when the human input component is driven in the first rotation direction, and to disengage when the human input component is driven in the second rotation direction opposite to the first rotation direction, so as to decouple the human input component from the output component.

[0016] The manual input component is connected to the planet carrier of the planetary gear set, and the output component is connected to the gear ring of the planetary gear set.

[0017] In a preferred embodiment, the electric-assisted continuously variable transmission (CVT) is centrally mounted and integrally arranged at the bottom bracket position of the bicycle frame. The human input component is the bottom bracket. The CVT further includes a housing and a countershaft assembly. The housing is fixedly mounted on the bicycle frame. The bottom bracket is rotatably connected to the housing via bearings. The planetary gear set is fixedly connected to the bottom bracket via a planetary carrier. The planetary gear set, motor, first one-way clutch, second one-way clutch, third one-way clutch, and countershaft assembly are disposed inside the housing. The countershaft assembly includes a countershaft input gear, a countershaft, a first countershaft output gear, and a second countershaft output gear. The countershaft is rotatably connected to the housing and fixedly connected to the countershaft input gear to rotate synchronously with the countershaft input gear. The first countershaft output gear is coaxially arranged with the countershaft and is sleeved on the countershaft via the first one-way clutch. The second countershaft output gear is coaxially arranged with the countershaft and is sleeved on the countershaft via the second one-way clutch.

[0018] In a preferred embodiment, the planetary gear set further includes a planetary gear set input gear and a coupling gear. The motor is provided with a motor output gear that meshes with the countershaft input gear. The first countershaft output gear is connected to the sun gear of the planetary gear set via the planetary gear set input gear. The second countershaft output gear is connected to the ring gear of the planetary gear set and the output component via the coupling gear.

[0019] In a preferred embodiment, the electric-assisted continuously variable transmission (CVT) is a hub type, located at the rear wheel hub of the bicycle and integrated inside the hub. The human input component is a freewheel mounted on the main shaft, which is fixed to the rear fork of the frame. The output component is rotatably connected to the main shaft via bearings. The freewheel is sleeved on the main shaft and rotatably connected to the main shaft via bearings. The planet carrier of the planetary gear set is fixedly connected to the freewheel, and the ring gear of the planetary gear set is fixedly connected to the output component.

[0020] In a preferred embodiment, the electric power-assisted continuously variable transmission further includes a transmission mechanism disposed between the motor and the planetary gear set, wherein the planetary gear set, the motor, the first one-way clutch, the second one-way clutch, the third one-way clutch, and the transmission mechanism are disposed inside the output component housing.

[0021] In a preferred embodiment, the transmission mechanism further includes a transmission sun gear, a plurality of transmission planet gears, a transmission ring gear, a transmission planet carrier, and a transmission mechanism countershaft. The plurality of transmission planet gears are mounted on the transmission planet carrier and mesh with the transmission sun gear. The transmission ring gear meshes with the plurality of transmission planet gears. The transmission planet carrier is fixedly connected to the main shaft. The transmission ring gear is fixedly connected to the transmission mechanism countershaft.

[0022] In a preferred embodiment, the first one-way clutch is further disposed between the countershaft of the transmission mechanism and the sun gear of the planetary gear set, with the inner ring of the first one-way clutch connected to the sun gear of the planetary gear set and the outer ring connected to the countershaft of the transmission mechanism; the second one-way clutch is disposed between the countershaft of the transmission mechanism and the output component, with the inner ring of the second one-way clutch connected to the countershaft of the transmission mechanism and the outer ring connected to the output component; and the third one-way clutch is disposed between the flywheel and the ring gear of the planetary gear set.

[0023] In a preferred implementation, the electric power-assisted continuously variable transmission (CVT) further includes a pure manual mode, a power-split assist mode, and a parallel assist mode. Through the engagement and disengagement of the first one-way clutch, the second one-way clutch, and the third one-way clutch, the following power transmission paths are formed respectively:

[0024] In the pure manual mode, the motor does not output driving torque, and the first one-way clutch and the second one-way clutch are in an overrunning disengaged state; the torque of the manual input component is transmitted unidirectionally to the gear ring via the third one-way clutch of the third transmission branch, and the gear ring drives the output component.

[0025] In the power split assist mode, the motor torque is transmitted to the sun gear of the planetary gear assembly via the first transmission branch and the first one-way clutch. The torque of the manual input component is input to the planet carrier of the planetary gear assembly via the third transmission branch. The motor torque and the manual torque are coupled in the planetary gear assembly and then output by its ring gear to drive the output component. The second one-way clutch is in the overrunning disengagement state to block the power transmission of the motor to the output component via the second transmission branch.

[0026] In the parallel assist mode, the torque of the motor is transmitted to the output component via the second transmission branch and the second one-way clutch. At the same time, the torque of the manual input component is transmitted unidirectionally to the ring gear of the planetary gear assembly via the third transmission branch and the third one-way clutch, thereby driving the output component, so as to form a parallel drive of the output component by the manual input branch and the motor branch.

[0027] In a preferred embodiment, the planetary gear assembly further comprises two mutually coupled planetary gears: a first planetary gear assembly and a second planetary gear assembly. The first planetary gear assembly includes a meshing first sun gear, a first planet carrier, a first ring gear, and a plurality of first planet gears. The second planetary gear assembly includes a meshing second sun gear, a second planet carrier, a second ring gear, and a plurality of second planet gears. The first transmission branch connects the motor's output shaft to the first sun gear of the first planetary gear assembly. The second transmission branch connects the motor's output shaft to the output component. The third transmission branch is disposed between the manual input component and the output component via the second planetary gear assembly. The manual input component is fixedly connected to the second planet carrier, and the output component is drively connected to the first ring gear. A first one-way clutch is disposed on the first transmission branch, a second one-way clutch is disposed on the second transmission branch, and a third one-way clutch is disposed on the third transmission branch.

[0028] The first gear ring is driven by the second gear ring or the second sun gear: when driven by the second gear ring, the first gear ring and the second gear ring jointly drive the output component, and the first planet carrier is driven by the second sun gear; when driven by the second sun gear, the first gear ring and the second sun gear jointly drive the output component, and the first planet carrier is driven by the second gear ring.

[0029] On the other hand, this application also provides a control method for an electric power-assisted continuously variable transmission as described in any of the above claims, the control method comprising:

[0030] Step 1: Obtain vehicle operating condition information;

[0031] Step 2: When the operating condition information determines that the current condition is a start-up, low-speed and / or medium-to-small load demand condition, the control motor outputs the first one-way clutch in the direction of the first transmission branch and the motor power is input to the sun gear of the planetary gear assembly through the first transmission branch. The second one-way clutch disengages, cutting off the direct transmission of motor power to the output component. At the same time, the manual input component is allowed to input manual power into the planetary gear assembly through the fixedly connected planetary carrier, so that the motor power and manual power are split in the planetary gear assembly and combined at the gear ring. The output is then output by the gear ring and the output component connected to it, forming a power splitting assist mode.

[0032] Step 3: When the operating condition information indicates that the current condition is low speed and high load demand, the control motor outputs the second one-way clutch in the direction of the second transmission branch and closes the second one-way clutch. The motor power is directly input to the output component through the second transmission branch. The first one-way clutch disengages, cutting off the input of motor power to the sun gear. At the same time, the manual input component is allowed to input manual power to the output component through the third one-way clutch and the gear ring of the planetary gear assembly. This allows the motor power and the manual power to be combined in parallel at the output component to form a parallel assist mode.

[0033] Step 4: When it is determined based on the operating condition information that electric assistance is not needed or the battery power is lower than the preset threshold, the motor is controlled to stop output, so that the motor output shaft is in an idling state. Only the human input component is allowed to drive the output component through the planetary carrier and / or the third one-way clutch, thus forming a pure human riding mode.

[0034] Step 5: Repeat Step 1 in real time, and switch between power shunt assist mode, parallel assist mode and pure manual mode according to the updated operating condition information.

[0035] The beneficial effects of this application are:

[0036] First, the electric-assisted continuously variable transmission (CVT) of this application connects the human input component to the planetary carrier of the planetary gear set and connects the output component to the ring gear. It includes a first transmission branch from the motor to the sun gear, a second transmission branch from the motor to the output component, and a third transmission branch from the human input component to the output component via the planetary gear set. Each of these three branches is equipped with a one-way clutch, allowing the motor torque to be selectively input to the sun gear via the first transmission branch to participate in planetary gear set speed ratio adjustment, or directly transmitted to the output component via the second transmission branch, under different riding conditions. The human torque drives the output component to rotate via the third transmission branch and the ring gear, while the third one-way clutch... The transmission is allowed in the first direction of rotation and separated in the opposite direction, thereby blocking torque back transmission when manually driven in the opposite direction or when the output end is reversed, reducing drag loss and reverse torque impact, and improving transmission smoothness and efficiency. As a result, continuous and smooth stepless speed change can be achieved under the compact and closed structure of the wheel hub, and the effective speed ratio range can be expanded. This reduces the continuous working time of the motor in the low-speed, high-load, and low-efficiency zone, improving the overall vehicle energy efficiency and range performance. In addition, the main transmission and speed change components are arranged inside the wheel hub, reducing the dependence of exposed transmission components on lubrication and the environment, reducing wear and maintenance frequency caused by mud and sand intrusion, and the overall structure is more conducive to sealing, protection, reliability improvement, and manufacturing and assembly.

[0037] Secondly, in the preferred implementation, this application further adopts a centrally mounted electric power-assisted continuously variable transmission (CVT) located at the bottom bracket position of the frame. The planetary gear set, motor, various one-way clutches, and countershaft assembly are integrated inside the housing, providing good sealing protection and compact arrangement for the transmission and gear shifting mechanism. The countershaft assembly serves as the intermediate transmission hub for the motor output. The motor power input is achieved through the meshing of the motor output gear and the countershaft input gear. The power is then introduced to the sun gear via the first countershaft output gear and planetary gear set input gear to participate in speed ratio adjustment. The power is introduced to the gear ring and output component via the second countershaft output gear and coupling gear to form a direct power assist channel. One-way transmission and reverse isolation are achieved through the first and second one-way clutches, respectively. This allows for a more reasonable power path selection under different load and speed conditions, reducing reverse torque drag and transmission shock, and improving transmission efficiency and riding smoothness. In addition, the human input path, which is fixedly connected to the planetary carrier and the bottom bracket, and the power assist path, which is split by the motor via the countershaft, are centrally arranged inside the housing, which helps to shorten the power transmission chain, improve assembly consistency, and enhance manufacturing controllability.

[0038] Third, in the preferred implementation, the hub-type electric power-assisted continuously variable transmission of this application can be further integrated into the rear wheel hub and arranged inside the output component housing, so that the motor, planetary gear set, one-way clutch and transmission mechanism are in a closed space, which can effectively isolate mud and rainwater and reduce the dependence of exposed transmission components on lubrication, thereby reducing wear and maintenance frequency and improving reliability and appearance consistency; by setting the flywheel on the main shaft and using the flywheel to drive the planetary carrier, and the human power is transmitted through the planetary gear set to the gear ring fixed to the output component, the riding habit of conventional rear-wheel drive can be maintained. At the same time, the third one-way clutch is arranged between the flywheel and the gear ring, so that effective torque transmission can be achieved during riding, while blocking the return transmission in the reverse drive or coasting state of the wheel, reducing drag. Resistance and impact; In addition, a transmission mechanism consisting of a variable speed sun gear, variable speed planetary gears, variable speed ring gear, and variable speed planetary carrier is set between the motor and the planetary gear set. The variable speed planetary carrier is fixed to the main shaft, and the variable speed ring gear is fixed to the countershaft of the transmission mechanism. The speed ratio of the motor output can be changed in a compact space. With the first one-way clutch, the power of the countershaft is sent unidirectionally to the sun gear of the planetary gear set for speed regulation. With the second one-way clutch, the power of the countershaft is sent unidirectionally to the output component to form a direct power assist channel. This results in a more reasonable power path and speed ratio matching under different vehicle speeds and loads, reduces the time the motor stays in the low-speed, high-load, low-efficiency zone, improves the overall transmission efficiency and riding smoothness, and is conducive to achieving lightweight and assembly consistency.

[0039] Fourth, in the preferred implementation, this application further utilizes the engagement and disengagement of the first, second, and third one-way clutches to achieve clear power organization for three operating modes without adding a complex shifting mechanism: In pure manual mode, for starting or low-speed driving, the motor does not participate in output and the first and second one-way clutches are in disengagement; the manual torque is transmitted unidirectionally from the manual input component to the gear ring output via the third one-way clutch, thereby maintaining low-resistance, low-energy pedal drive and reducing passive drag on the motor side; in power-split assist mode, for starting, low-speed, and / or medium-load conditions, the motor torque is input to the sun gear via the first transmission branch, The human torque is input to the planetary carrier, and after coupling within the planetary gear set, it is output through the ring gear. Simultaneously, the second one-way clutch is in overrunning disengagement to block the direct drive channel of the motor, allowing the motor and human power to work together in a more suitable speed and load range. In parallel assist mode, to address the need for high torque when the wheels are accelerating at low speeds and under heavy loads, the motor directly drives the output component through the second transmission branch, while human power is transmitted unidirectionally through the third one-way clutch to drive the ring gear, achieving the superposition of the two torques at the output end, thereby obtaining higher instantaneous driving force and acceleration response. At the same time, each one-way clutch blocks the reverse torque back transmission, reducing impact and noise, improving riding smoothness, and reducing energy loss and component wear.

[0040] Fifth, the control method of the electric power-assisted continuously variable transmission (CVT) of this application acquires real-time vehicle operating condition information and controls the motor to output along the first or second transmission branch accordingly. This allows the first and second one-way clutches to close and disengage as needed. During start-up, low-speed, or high-torque demand, the motor power is input to the sun gear and combined with human power in the planetary gear set for output. During low-speed, high-load demand, the motor power is directly input to the output component, and human power is allowed to participate in parallel superposition at the output end via the third one-way clutch to obtain stronger driving force and faster response. When no assistance is needed for start-up or when the battery is insufficient, the motor is stopped and idled, with only human power driving the output component via the planetary gear set and the third one-way clutch, reducing energy consumption and minimizing motor-side drag loss. Furthermore, by cyclically updating operating condition information, continuous switching between the three modes is achieved, ensuring that the motor and human power are always in a more matched power and efficiency range under different vehicle speeds, gradients, and load conditions. This improves the vehicle's range, riding smoothness, and reliability, while reducing impact and wear caused by improper energy return. Attached Figure Description

[0041] Figure 1 This is a simplified structural diagram of the electric power-assisted continuously variable transmission (CVT) according to Embodiment 1 of the present invention;

[0042] Figure 2 This is a simplified structural diagram of the electric power-assisted continuously variable transmission (CVT) of Embodiment 2 of the present invention;

[0043] Figure 3 This is a schematic diagram of the power transmission path of the electric power-assisted continuously variable transmission in the manual mode starting condition of Embodiment 2 of the present invention.

[0044] Figure 4 This is a schematic diagram of the power transmission path of the electric power-assisted continuously variable transmission in power split mode according to Embodiment 2 of the present invention.

[0045] Figure 5 This is a schematic diagram of the power transmission path of the electric power-assisted continuously variable transmission in parallel mode according to Embodiment 2 of the present invention.

[0046] Figure 6 This is a lever principle diagram of the electric power-assisted continuously variable transmission (CVT) in Embodiment 2 of the present invention, illustrating the transition from manual start-up to power splitting operation.

[0047] Figure 7 This is a lever principle diagram of the electric power-assisted continuously variable transmission (EVV) in Embodiment 2 of the present invention, illustrating the starting and parallel operation conditions.

[0048] Figure 8 This is a schematic diagram of the lever principle for switching between parallel and power split modes of the electric power-assisted continuously variable transmission (CVT) according to Embodiment 2 of the present invention.

[0049] Figure 9 This is a simplified structural diagram of the electric power-assisted continuously variable transmission (CVT) of Embodiment 3 of the present invention;

[0050] Figure 10 This is a cross-sectional view of the overall structure of the electric power-assisted continuously variable transmission (CVT) of Embodiment 3 of the present invention;

[0051] Figure 11 This is a simplified structural diagram of the electrically assisted continuously variable transmission (CVT) of Embodiment 4 of the present invention.

[0052] Among them, 1-central shaft; 2-planetary gear assembly; 20-ring gear; 200-coupling gear; 21-planet carrier; 22-sun gear; 220-planetary gear input gear; 23-planet gear; 3-first one-way clutch; 4-motor; 40-stator; 41-rotor; 410-motor output gear; 5-second one-way clutch; 6-output component; 7-third one-way clutch; 8-countershaft assembly; 80-countershaft input gear; 81-countershaft; 82-first countershaft output gear; 83-second countershaft output gear; 9-housing; 100-flywheel; 101-main shaft; 10-transmission mechanism; 11-transmission sun gear; 12-transmission planetary gear; 13-transmission ring gear; 14-transmission planetary carrier; 15-transmission mechanism countershaft; 2-1-first planetary gear assembly; 2-2-second planetary gear assembly. Detailed Implementation

[0053] To enable those skilled in the art to better understand the technical solutions of this application, the following will provide a more detailed description of this application in conjunction with the accompanying drawings and embodiments.

[0054] The directional terms such as above, below, left, right, front, and back used in this application are based on the positional relationships shown in the attached drawings. Different attached drawings may result in different positional relationships, therefore they should not be interpreted as limitations on the scope of protection.

[0055] In this application, the terms "installation," "connection," "interlocking," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, an integral connection, a mechanical connection, an electrical connection, or a connection that allows communication between components. They can also refer to a direct connection or an indirect connection through an intermediate medium. They can refer to the internal connection of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0056] Example 1

[0057] As per the instruction manual Figure 1 The electric continuously variable transmission (CVT) of the present invention is suitable for installation at the bottom bracket or wheel hub of a bicycle. The CVT includes a human input component, a planetary gear set 2, a first one-way clutch 3, a motor 4, a second one-way clutch 5, an output component 6, and a third one-way clutch 7. The human input component is the bottom bracket 1 and / or a flywheel 100 mounted on the main shaft. The planetary gear set 2 includes a sun gear, a planet carrier, a ring gear, and several planet gears that mesh with each other. A first transmission branch A1 is provided between the output shaft of the motor 4 and the sun gear of the planetary gear set 2, and the first one-way clutch 3 is mounted on the first transmission branch A1. A second transmission branch A2 is provided between the output shaft of the motor 4 and the output component 6, and the second one-way clutch 5 is mounted on the second transmission branch A2. A third transmission branch A3 is provided between the human input component and the output component 6 via the planetary gear set 2, and the third one-way clutch 7 is mounted on the third transmission branch A3. The human input component is fixedly connected to the planet carrier of the planetary gear set 2 for inputting human power into the planetary gear set 2. The output component 6 is connected to the gear ring of the planetary gear assembly 2, so that the rotational speed of the gear ring is used to drive the output component 6.

[0058] The motor 4 can operate in both directions, outputting power to the first transmission branch A1 and the second transmission branch A2 respectively. A first one-way clutch 3 is located in the first transmission branch A1. When the first transmission branch A1 is active, the first one-way clutch 3 is closed, allowing the output torque of the motor 4 to be transmitted unidirectionally to the sun gear of the planetary gear set 2 via the first transmission branch A1, driving the sun gear to rotate in the second rotation direction. When the first transmission branch A1 is inactive, the first one-way clutch 3 is disengaged, cutting off the power transmission between the first transmission branch A1 and the sun gear of the planetary gear set 2. A second one-way clutch 5 is located in the second transmission branch A2. When the second transmission branch A2 is active, the second one-way clutch 5 is closed, allowing the output torque of the motor 4 to be transmitted unidirectionally to the output component 6 via the second transmission branch A2, driving the output component 6 and the ring gear of the planetary gear set 2 to rotate in the first rotation direction. When the second transmission branch A2 is inactive, the second one-way clutch 5 is disengaged, cutting off the power transmission between the second transmission branch A2 and the output component 6. The third one-way clutch 7 is arranged in the third transmission branch A3. When the manual input component rotates in the first rotation direction, the third one-way clutch 7 is closed, allowing the torque of the manual input component to drive the output component 6 to rotate unidirectionally through the third transmission branch A3 and the ring gear of the planetary gear assembly 2. When the manual input component rotates in the second rotation direction, the third one-way clutch 7 is disengaged, disengaging the manual input component from the output component 6. In this application, the first rotation direction is the forward direction of the bicycle wheel, and the second rotation direction is the reverse direction of the bicycle wheel.

[0059] Preferably, the first one-way clutch 3, the second one-way clutch 5, and the third one-way clutch 7 employ one-way bearings.

[0060] In the power-split assist mode, the motor power is input to the planetary gear assembly 2 via the sun gear through the first transmission branch A1, and the manual power is input to the planetary gear assembly 2 via the planet carrier through the manual input component. After power coupling within the planetary gear assembly 2, the power is transmitted to the output component 6 via the ring gear of the planetary gear assembly 2, thus constituting the power-split assist mode. Since the speed of the output component 6 is determined by both the speed of the manual input component and the speed of the motor 4, continuously variable transmission (CVT) can be achieved.

[0061] In parallel assist mode, the motor power is directly input to the output component 6 through the second transmission branch A2, and the human power is input to the gear ring of the planetary gear assembly 2 through the third one-way clutch 7, and is driven by the gear ring to output the output component 6. The motor power and the human power are output in parallel at the output component 6, forming a parallel assist mode.

[0062] The electric-assisted continuously variable transmission (CVT) of this application, by setting up first, second, and third transmission branches between the human input component, motor 4, and planetary gear set 2, and cooperating with three one-way clutches, achieves the following: In power-split assist mode, the motor power and human power are input to the same planetary gear set via the sun gear and planetary carrier respectively, realizing power coupling output within the planetary gear set 2 and forming electric-assisted CVT; In parallel assist mode, the motor power is directly input to the output component 6 via the second transmission branch A2, and the human power is input to the gear ring and output component 6 via the third transmission branch A3, realizing parallel power output at the output component 6. Thus, under the premise of compact structure and flexible arrangement (it can be arranged at the bottom bracket or wheel hub position), it achieves efficient superposition of human power and motor assistance and CVT, improving riding efficiency and comfort. The reasonable configuration of the one-way clutches ensures reliable transmission and smooth idling in forward and reverse conditions, and the overall transmission efficiency is high and the adaptability to a wide range of working conditions.

[0063] Example 2

[0064] like Figure 2 As shown, the electric power-assisted continuously variable transmission (CVT) of this embodiment is a mid-mounted CVT, which is arranged at the bottom bracket position of the bicycle frame to work in conjunction with the bottom bracket 1 to achieve stepless superposition of human power and motor power output. This mid-mounted CVT includes: a bottom bracket 1, a housing 9, and a planetary gear set 2, a first one-way clutch 3, a motor 4, a second one-way clutch 5, an output component 6, a third one-way clutch 7, and a countershaft assembly 8 disposed inside the housing 9.

[0065] The housing 9 is fixedly mounted on the bicycle frame, and the motor 4 is disposed inside the housing 9. The motor 4 includes a stator 40 and a rotor 41 disposed opposite to the stator 40. A motor output gear 410 is fixedly provided on the output shaft of the rotor 41. The motor 4 can be any of the applicable forms such as a brushed DC motor, a brushless DC motor, or a permanent magnet synchronous motor, and the motor output gear 410 is preferably a pinion.

[0066] The secondary shaft assembly 8 is used to establish two different transmission branches between the motor 4 and the planetary gear set 2 and the output component 6, namely the first transmission branch A1 and the second transmission branch A2. The secondary shaft assembly 8 includes a secondary shaft input gear 80, a secondary shaft 81, a first secondary shaft output gear 82, and a second secondary shaft output gear 83. The secondary shaft 81 is rotatably connected to the housing 9 via bearings. The secondary shaft input gear 80, the first secondary shaft output gear 82, and the second secondary shaft output gear 83 are sequentially and alternately sleeved on the secondary shaft 81. The secondary shaft input gear 80 is fixedly connected to the secondary shaft 81 and meshes with the motor output gear 410, thereby causing the secondary shaft 81 to rotate under the drive of the motor 4.

[0067] The central shaft 1 passes through both ends of the housing 9 and is rotatably connected to the housing 9 via bearings. The planetary gear assembly 2 is a single-stage planetary gear mechanism, including a gear ring 20, a planet carrier 21, a sun gear 22, and several planet gears 23. The sun gear 22 is located at the center of the planetary gear assembly 2, and one end of it is coaxially connected to a rigidly connected planetary gear input gear 220. The sun gear 22 and the planetary gear input gear 220 are mounted on the central shaft 1 and rotatably connected to the central shaft 1 via bearings. The planetary gear input gear 220 meshes with the first countershaft output gear 82 to receive power from the first countershaft output gear 82. The planet carrier 21 is mounted on the central shaft 1 and is fixedly connected to the central shaft 1 by a spline or key connection. Several planet gears 23 are evenly distributed on the planet carrier 21 and mesh with the sun gear 22. One end of the gear ring 20 is arranged around and meshes with the planetary gear 23, while the other end is provided with a coupling gear 200 and meshes with the output gear 83 of the second countershaft. The gear ring 20 is fixedly connected to the output component 6 through the coupling gear 200. It can be a one-piece structure or it can be connected by a spline to rotate as a whole. It is used to receive the power transmitted from the output gear 83 of the second countershaft and rotate together with the gear ring 20 to ultimately drive the output component 6. Through the above connection, the planetary carrier 21 serves as the human input component, the sun gear 22 serves as the motor-side input component, and the gear ring 20 serves as the output component of the planetary gear set 2.

[0068] The first one-way clutch 3 is disposed between the countershaft 81 and the first countershaft output gear 82. The first one-way clutch 3 is configured such that when the motor 4 drives the countershaft 81 to rotate in the second motor rotation direction, the first one-way clutch 3 is in the closed state, so that the countershaft 81 and the first countershaft output gear 82 establish a one-way locking connection. The torque of the motor 4 is transmitted unidirectionally to the first countershaft output gear 82 through the countershaft 81, and further transmitted to the sun gear 22 through the planetary gear input gear 220, so that the sun gear 22 rotates in the second rotation direction in a gear meshing relationship with the countershaft 81. When the motor 4 rotates in the first motor rotation direction and the countershaft 81 rotates in the second rotation direction, the first one-way clutch 3 is in the overrunning disengagement state, so that the first countershaft output gear 82 rotates freely relative to the countershaft 81, thereby cutting off the power coupling between the countershaft 81 and the sun gear 22 through the first transmission branch A1, and preventing the motor 4 from causing undesirable drag on the sun gear 22 through A1.

[0069] The second one-way clutch 5 is disposed between the secondary shaft 81 and the second secondary shaft output gear 83, and its working direction matches the transmission direction of the motor 4 driving the output member 6 via the second transmission branch A2 in the first motor rotation direction. The second one-way clutch 5 is configured such that when the motor 4 drives the secondary shaft 81 to rotate in the first motor rotation direction to put the second transmission branch A2 into operation, the second one-way clutch 5 is in the closed state, and the torque of the motor 4 is transmitted unidirectionally to the second secondary shaft output gear 83 via the secondary shaft 81, and further transmitted to the gear ring 20 and the output member 6 via the coupling gear 200, causing the output member 6 to rotate in the first rotation direction; when the output member 6 overshoots the secondary shaft 81 in the second rotation direction, the second one-way clutch 5 is in the disengaged state to cut off the reverse drag of the A2 branch.

[0070] The first rotation direction is preferably the positive rotation direction of the output component 6 when the bicycle moves forward, and the second rotation direction is the opposite direction to the first rotation direction.

[0071] The third one-way clutch 7, installed in the third transmission branch A3, has one end fitted and fixed to the central shaft 1, and the other end connected to the gear ring 20. The working direction of the third one-way clutch 7 is set as follows: when the central shaft 1 rotates in the first rotation direction, the third one-way clutch 7 is closed, transmitting the torque of the central shaft 1 unidirectionally to the gear ring 20; when the central shaft 1 rotates in the second rotation direction, the third one-way clutch 7 idles or disengages, and the gear ring 20 does not drive the central shaft 1 in reverse, thus preventing the wheels from reversing the pedals. Human power can be achieved through the third transmission branch A3 for pure human output, or in parallel with the second transmission branch A2 for output.

[0072] In this embodiment, the sun gear 22 of the planetary gear set 2 of the centrally mounted electric power continuously variable transmission is directly or indirectly (through the countershaft assembly 8) connected to the motor 4, the planet carrier 21 is connected to the central shaft 1, and the ring gear 20 is connected to the output component 6. Based on the working principle of the planetary gear set, the following kinematic and dynamic relationships can be obtained, as shown in equations (1) and (2):

[0073] (1)

[0074] (2)

[0075] In equations (1) and (2): These are the rotational speeds of the sun gear 22, the ring gear 20 (output component 6), and the planet carrier 21 (central shaft 1), respectively. These are the torques of the sun gear 22, the ring gear 20 (output component 6), and the planet carrier 21 (central shaft 1), respectively. This is the speed ratio of planetary gear assembly 2.

[0076] Let the transmission ratio between the motor output gear 410 and the planetary gear input gear 220 be i1, and the speed of motor 4 be... ,but:

[0077] = / (3)

[0078] Substituting equation (3) into equation (1), we can obtain the speed relationship between motor 4, central shaft 1, and output component 6 under power shunt operation:

[0079] (4)

[0080] Assuming the transmission ratio between the motor output gear 410 and the coupling gear 200 is i2, then the rotational speed of the output component 6 under pure electric and parallel operation conditions is: = / .

[0081] Let the transmission ratio between the first countershaft output gear 82 and the planetary gear set input gear 220 be denoted as i. 12 The transmission ratio between the second auxiliary shaft output gear 83 and the coupling gear 200 is denoted as i. 22 To prevent the mechanism from locking up due to the simultaneous engagement of the first one-way clutch 74 and the second one-way clutch 75, the following condition must be met: 12 ≤i 22 .

[0082] In this embodiment, the housing 9 is used to install and support the above-mentioned components, forming a sealed or semi-sealed structure, and can be filled with grease to reduce wear. The output component 6 outputs the rotational speed of the gear ring 20 to the rear wheel through mechanical transmission, which can be chain drive, belt drive, or shaft drive.

[0083] In this embodiment, by controlling the rotation direction of motor 4 and utilizing the cooperation of three one-way clutches, multiple operating conditions are achieved, including manual mode, power split mode, parallel mode, and pure electric mode, resulting in stepless power assistance. For ease of explanation, the following descriptions will be combined with... Figures 3-5 Three typical operating conditions are explained.

[0084] As per the instruction manual Figure 3 , Figure 3 This is a schematic diagram of the power transmission path during the start-up operation in manual mode. When starting or traveling at low speed, motor 4 can be turned off, and riding can be done solely by manual power.

[0085] Specifically, the rider drives the bottom bracket 1 to rotate in the first rotation direction via pedals. The third one-way clutch 7 engages, and the torque of the bottom bracket 1 is transmitted to the coupling gear 200 and the ring gear 20 via the third one-way clutch 7. The coupling gear 200 drives the ring gear 20 and the output component 6 to rotate synchronously in the first rotation direction, driving the wheels to start. Because the ring gear 20 and the coupling gear 200 rotate at the same speed, the planetary gear input gear 220 also rotates in the same direction and speed as the ring gear 20. The planetary gear assembly 2 is in a near-locked state, and the planetary gears 23 have virtually no relative movement. The planetary gear input gear 220 and the coupling gear 200 respectively drive the first countershaft output gear 82 and the second countershaft output gear 83 to rotate in the second rotation direction. 12 ≤ i 22 Therefore, the rotational speed of the first countershaft output gear 82 is no greater than the rotational speed of the second countershaft output gear 83. Under this condition, the first countershaft output gear 82 drives the first one-way clutch 3 to close along the second rotational direction, while the second countershaft output gear 83 rotates at a higher speed relative to the countershaft 81, keeping the second one-way clutch 5 disengaged. Thus, in pure manual mode, the entire transmission is equivalent to a gear transmission mechanism with the ring gear 20 as the rigid output, ensuring easy starting and high transmission efficiency.

[0086] As per the instruction manual Figure 4 , Figure 4 This is a schematic diagram of the power transmission path under power split mode. Under medium to low load and high speed conditions, motor 4 can operate in power split mode.

[0087] Specifically, in power split mode, the motor 4 outputs power along the second rotation direction via the motor output gear 410, the countershaft input gear 80, the countershaft 81, and the closed first one-way clutch 3, sequentially to the first countershaft output gear 82 and the planetary gear input gear 220, thereby driving the sun gear 22 to rotate along the second rotation direction. Simultaneously, the rider drives the bottom shaft 1 to rotate along the first rotation direction via pedals. The bottom shaft 1 is fixedly connected to the planetary carrier 21, and human power is input to the planetary gear assembly 2 along the first rotation direction via the planetary carrier 21. Under this condition, inside the planetary gear assembly 2, the sun gear 22 (motor side) and the planetary carrier 21 (human power side) jointly drive the planetary gear 23 to rotate. The planetary gear 23 combines the two power paths onto the ring gear 20, causing the ring gear 20 to drive the coupling gear 200 and the output component 6 to rotate along the first rotation direction, thus achieving power split output. Since the rotational speed of the planetary carrier 21 and the central shaft 1 is lower than that of the ring gear 20, the third one-way clutch 7 is disengaged. Manual power is only transmitted through the planetary carrier 21 to the planetary gear assembly 2, without directly driving the ring gear 20 via the third one-way clutch 7. In the aforementioned power splitting mode, as the sun gear 22 rotates along the second rotational direction, the planetary gear 23 engages with the ring gear 20, causing the ring gear 20 and the coupling gear 200 to drive the second countershaft output gear 83 to rotate along the second rotational direction. However, at this time, the second one-way clutch 5 is disengaged, and the second transmission branch A2 does not directly drive the output component 6. The motor 4 will not directly drive the output component 6 via the second transmission branch A2.

[0088] In this mode, the motor power and human power are coupled inside the planetary gear set, resulting in high output power. It is suitable for medium and small loads and high-speed conditions, and achieves stepless speed change through the speed ratio characteristics of the planetary gear set.

[0089] Under the power-split continuously variable transmission (CVT) operating condition, the power flow relationship is as shown in equation (5):

[0090] (5)

[0091] in, This refers to the power of the sun gear 21, the ring gear 23 (output gear 4), and the planet carrier 22 (central shaft 1).

[0092] The relationship between the assist ratio and λ is shown in equation (6):

[0093] λ= (6)

[0094] in, The torques of the sun gear 21 and planet carrier 22 (central shaft 1) are respectively. These represent the rotational speeds of the sun gear 21, motor 3, and planetary carrier 22 (central shaft 1), respectively. is the speed ratio from motor 3 to sun gear 21, and k is the speed ratio of planetary gear assembly 2.

[0095] According to equation (6), λ is related to the speed ratio of the motor and the central shaft. By adjusting the motor speed, the assist ratio λ can be steplessly adjusted to meet the needs of different working conditions.

[0096] As per the instruction manual Figure 5 , Figure 5 This is a schematic diagram of the power transmission path under parallel operation. When the wheels are accelerating at low speeds or under heavy loads, a large torque is required. Under power splitting, the motor outputs a large torque, which will create a large reaction force on the planetary carrier, causing foot kicking or excessive manual load. In this case, motor 4 can be switched to parallel mode.

[0097] Specifically, in parallel assist mode, the output of motor 4 along the first rotation direction is transmitted to the second one-way clutch 5 via motor output gear 410, countershaft input gear 80, and countershaft 81. The second one-way clutch 5 is in a closed state, and the torque of countershaft 81 is transmitted to coupling gear 200 via second countershaft output gear 83. This causes coupling gear 200, along with its fixedly connected gear ring 20 and output component 6, to rotate along the first rotation direction. Thus, the torque of motor 4 is directly output to output component 6 through the second transmission branch A2. The rider inputs human power by pedaling the bottom shaft 1 along the first rotation direction. The third one-way clutch 7 is in a closed state when gear ring 20 rotates along the first rotation direction. Human power is directly applied to gear ring 20 via the third one-way clutch 7, causing gear ring 20, coupling gear 200, and output component 6 to rotate synchronously along the first rotation direction. At this time, since the planetary gear input gear 220 and the coupling gear 200 rotate at the same speed in the first rotational direction after being meshed by the corresponding gears, and the second auxiliary shaft output gear 83 and the auxiliary shaft 81 are rigidly connected, they maintain the same speed in the second transmission branch A2 under steady-state parallel output conditions. According to the transmission ratio relationship i 12 ≤i 22 It can be seen that the rotational speed of the first secondary shaft output gear 82 is not greater than the rotational speed of the second secondary shaft output gear 83 and the secondary shaft 81. Under the above working conditions, the first one-way clutch 3 remains disengaged, the sun gear 22 will not obtain effective driving force through the first transmission branch A1, the motor 4 no longer inputs power to the planetary gear assembly 2 through the sun gear 22, and only achieves parallel assist output through the gear ring 20 and the output component 6.

[0098] In summary, in parallel mode, human power directly drives the gear ring 20 through the third one-way clutch 7, and the motor directly drives the coupling gear 200 and the output component 6 through the second one-way clutch 5. The two power sources are connected in parallel and superimposed at the output component 6 for output.

[0099] It should be noted that, under the power split mode, according to equation (2), the torque of the central shaft 1 satisfies equation (7):

[0100] (7)

[0101] The torque of the bottom bracket reflects the pedal force. When encountering great resistance or needing rapid acceleration, the torque of the bottom bracket is [not specified]. Increased pedaling force can cause discomfort for the rider. In parallel operation, the vehicle has stronger drive capability, outputting torque to all four wheels. Satisfying formula (8):

[0102] (8)

[0103] Where i2 is the speed ratio from motor 3 to coupling gear 9 (output wheel 4).

[0104] From formulas (7) and (8), we can obtain:

[0105] (9)

[0106] Compared to the power split mode, the parallel mode increases the driving (output) torque for the same input torque, thus greatly expanding the vehicle's driving capability.

[0107] The following section describes the operating conditions under the pure manual mode, power shunt mode, and parallel mode, in conjunction with the appendix to the instruction manual. Figure 6-8 The document further explains the switching between the manual start-up to power shunting mode, the start-up to parallel mode, and the parallel and power shunting modes.

[0108] Figure 6 This is a schematic diagram of the lever principle for the power splitting operation from manual start-up. Operation 1 is a pure manual start-up. Figure 6 At near-horizontal level, under pure human-powered start-up, motor 4 is shut off and idles. Neither the first one-way clutch 3 nor the second one-way clutch 5 transmits driving force from the motor. The rider drives planetary carrier 21(C) through the bottom bracket 1, the third one-way clutch 7 is engaged, and human power directly drives output component 6 through ring gear 20(R). Planetary gear assembly 2 is approximately closed, and the speeds of sun gear 22(S), planetary carrier 21(C), and ring gear 20(R) are basically equal, corresponding to a near-horizontal straight line on the lever. Condition 2 is when motor 4 begins to engage, entering the power split transition stage. Control motor 4 to start in the direction of power split mode, driving sun gear 22(S) through countershaft 81 and the first one-way clutch 3. At this time, human power is still input from planetary carrier 21(C). On the speed lever, with planetary carrier 21(C) as the fulcrum, with the equivalent speed of sun gear 22(S) (i.e., in formula 4)... As the speed of the gear ring 20 increases, the linear motion around the planetary carrier 21 (C) rotates upwards, increasing the speed of the gear ring 20 (R) and beginning to reflect the power synthesis of the motor and human power within the planetary gear set. Operating condition 3 is a stable power splitting condition. The first one-way clutch 3 remains closed, while the third one-way clutch 7 disengages because the speed of the planetary carrier 21 (C) is lower than that of the gear ring 20 (R). Human power enters the planetary gear set 2 only through the planetary carrier 21 (C), and the motor power is input through the sun gear 22 (S). The two power sources are split at the planetary gears and synthesized at the gear ring 20 (R) for output. Operating condition 3, with the planetary carrier 21 (C) as the fulcrum, allows for the drawing of line segments with different slopes. This reflects that, under a given central shaft speed, adjusting the speed of the motor 4 continuously changes the output speed and assist ratio, achieving stepless speed regulation.

[0109] Figure 7 This is a diagram illustrating the lever principle from initial operation to parallel operation. The diagram for the purely manual initial operation stage is attached. Figure 7 In operating condition 1, manual power directly drives the ring gear 20(R) via the third one-way clutch 7. The planetary gear set 2 is approximately closed, and the sun gear 22(S), planet carrier 21(C), and ring gear 20(R) move at equal speeds, with the three points on the same straight line. Operating condition 2 involves switching to parallel mode. The motor 4 rotates in the parallel mode direction, directly driving the coupling gear 200 and ring gear 20(R) via the second one-way clutch 5. Simultaneously, the third one-way clutch 7 closes, and manual power still directly acts on the ring gear 20(R). The two power paths are superimposed in parallel at the output component 6. Because the planetary gear set input gear 220 rotates at the same speed as the coupling gear 200, the planetary gear set 2 is again in a nearly closed state. The sun gear 22(S), planet carrier 21(C), and ring gear 20(R) maintain equal speeds, but the overall rotational speed is increased. Therefore, the attached... Figure 8 Both Condition 1 and Condition 2 are represented by horizontal lines, but at different heights, corresponding to different vehicle speeds.

[0110] Figure 8 This is a schematic diagram illustrating the lever principle for switching between parallel and power-sharing modes. Operating condition 1 represents the synchronous transition between parallel and power-sharing modes. During the switch from power-sharing to parallel (reverse switching), the speed of motor 4 is adjusted to gradually bring the internal motion of the planetary gear set 2 closer to closed: the speeds of the sun gear 22 (S), planet carrier 21 (C), and ring gear 20 (R) tend to be consistent. At this time, the first one-way clutch 3 and the second one-way clutch 5 are in the critical zone of being engaged and disengaged. Motor 4 gradually transitions from "participating in power-sharing through the sun gear 22 (S)" to "directly driving the ring gear 20 (R) through the coupling gear 200." The power flow inside the planetary gear set 2 begins to weaken, but it has not yet fully entered a pure parallel state. From Figure 8As can be seen, Condition 1, located at the middle horizontal line, represents this synchronous switching condition: the equivalent speed, planetary carrier speed, and output speed on the MG side are numerically close, thus achieving a smooth transition between the two modes. Condition 2 is the power split mode, where motor 4 operates in the power split direction, driving the sun gear 22(S) via the first transmission branch A1. The equivalent motor speed is... The rider's human power is input through the central shaft 1 to drive the planetary carrier 21 (C), and the planetary carrier 21 (C) rotates at a speed of... The sun gear 22 (S) and the planet carrier 21 (C) are combined and fed onto the ring gear 20 (R) via the planet gear 23. The ring gear 20 (R) and the output component 6 rotate at a speed of... All three conditions are met. When the motor torque reverses, it transitions from operating condition 2 back to operating condition 1, thus completing the switching between power splitting and parallel operation.

[0111] As can be seen from the above embodiments, the mid-mounted electric power-assisted continuously variable transmission (CVT) of this embodiment achieves the following: The planetary gear set 2 is arranged at the central shaft 1, and the planetary carrier 21, the manual input shaft, the central shaft 1, the sun gear 22, the motor 4, the ring gear 20, and the output component 6 are respectively connected; a countershaft assembly 8 containing a first one-way clutch 3 and a second one-way clutch 5 is set between the motor output shaft and the planetary gear set and the output wheel, forming two mutually exclusive motor transmission branches; a third one-way clutch 7 is set between the central shaft 1 and the ring gear 20; This allows for the automatic selection of power split mode or parallel mode under different operating conditions by controlling the rotation direction of the motor 4, eliminating the need for a complex mechanical shifting mechanism; the power split mode is used under small to medium loads and high-speed conditions to improve riding comfort, while under high loads, such as rapid acceleration and steep slope conditions, it improves acceleration and climbing ability; the parallel mode reduces power loss caused by the planetary gear set transmission, improving overall efficiency; and the one-way clutches prevent the wheels from counter-driving the pedals, improving riding comfort.

[0112] Example 3

[0113] As per the instruction manual Figure 9 , Figure 10 As shown, this embodiment provides a hub-mounted electric continuously variable transmission (CVT) located at the rear wheel hub of a bicycle. This CVT is integrated inside the rear wheel hub and cooperates with the main shaft 101 fixed to the rear fork of the frame, achieving stepless superposition of human power and motor power output within the hub. The complete CVT includes a main shaft 101, a flywheel 100, a planetary gear set 2, a first one-way clutch 3, a motor 4, a second one-way clutch 5, an output component 6, a third one-way clutch 7, and a transmission mechanism 10. The transmission mechanism 10 includes a sun gear 11, multiple planetary gears 12, a ring gear 13, a planetary carrier 14, and a countershaft 15.

[0114] To ensure that the motor 4 has suitable speed and torque under different operating conditions, a speed-changing mechanism 10 is provided between the motor 4 and the planetary gear assembly 2 in this embodiment 2. The speed-changing mechanism 10 is a planetary gear transmission, including a variable speed sun gear 11, several variable speed planetary gears 12, a variable speed ring gear 13, and a variable speed planetary carrier 14. Similar to embodiment 1, the motor 4 is also preferably a brushless DC motor or a permanent magnet synchronous motor, with its stator 40 fixed in the hub housing and the rotor 41 connected to the variable speed sun gear 11. For simplicity, the stator and rotor are represented by block diagrams in the figure.

[0115] The main shaft 101 passes through both ends of the output component 6 and is rotatably connected to the output component 6 via bearings. The variable speed sun gear 11 is fixedly connected to the rotor shaft of the motor 4 and is used to receive the power output from the motor 4. The variable speed sun gear 11 and the rotor shaft of the motor 4 are rotatably connected to the main shaft 101 via bearings. The variable speed sun gear 11 is located at the center of the variable speed mechanism 10, and multiple variable speed planetary gears 12 are evenly distributed and mounted on the variable speed planetary carrier 14 and mesh with the variable speed sun gear 11. One end of the variable speed ring gear 13 is arranged around the variable speed planetary gear 12 and meshes with the variable speed planetary gear 12. The variable speed planetary carrier 14 is fixedly connected to the main shaft 101 and is used to support the variable speed planetary gear 12. The variable speed ring gear 13 is fixedly connected to the countershaft 15 of the variable speed mechanism and serves as the output component of the variable speed mechanism 10. (See attached instruction manual) Figure 10 The transmission mechanism's secondary shaft 15 is provided with a first one-way clutch mounting seat and a second one-way clutch mounting seat in the axial direction of the main shaft 101, with the second one-way clutch mounting seat located on the outer ring of the first one-way clutch mounting seat.

[0116] The planetary gear set 2 is a single-stage planetary gear mechanism, including a sun gear 22, a planet carrier 21, a ring gear 20, and multiple planet gears 23. The sun gear 22 is located at the center of the planetary gear set 2 and is rotatably connected to the main shaft 101 via bearings. One side of the outer ring of the sun gear 22 is connected to the first one-way clutch 3, serving as the input end on the motor side. The other side of the outer ring of the sun gear 22 meshes with multiple planet gears 23 surrounding it. The multiple planet gears 23 are supported by the planet carrier 21, which is fixedly connected to the flywheel 100 via splines or keys, serving as the human input end. The planet carrier 21 and the flywheel 100 are rotatably connected to the main shaft 101 via bearings. The ring gear 20 surrounds and meshes with the planet gears 23. The ring gear 20 is fixedly connected to the output component 6, which can be a one-piece structure or connected by splines to rotate as a single unit, thus acting as the output component of the planetary gear set. In this embodiment, the output component 6 is preferably a hub housing reliably connected to the rear wheel spokes or rim to transmit the rotational speed of the ring gear 20 to the wheel.

[0117] The first one-way clutch 3 and the second one-way clutch 5 are respectively installed in the first one-way clutch mounting seat and the second one-way clutch mounting seat of the transmission mechanism countershaft 15. The first one-way clutch 3 is located between the sun gear 22 and the transmission mechanism countershaft 15 (or the transmission ring gear 13), with its inner ring connected to the outer ring of the sun gear 22 and its outer ring connected to the transmission mechanism countershaft 15. The second one-way clutch 5 is located between the transmission mechanism countershaft 15 (or the transmission ring gear 13) and the output component 6, with its inner ring connected to the transmission mechanism countershaft 15 and its outer ring connected to the output component 6.

[0118] The first one-way clutch 3 is configured such that when the motor 4 rotates in the first rotation direction, the first one-way clutch 3 is in a closed state, transmitting the torque from the gear ring 13 unidirectionally to the sun gear 22 in the second rotation direction; when the motor 4 rotates in the second rotation direction, the sun gear 22 tends to rotate relative to the gear ring 13 in the first rotation direction, and the first one-way clutch 3 is in a disengaged state, thereby cutting off the power transmission between the gear ring 13 and the sun gear 22.

[0119] The second one-way clutch 5 is configured such that when the motor 4 rotates in the second rotation direction, the second one-way clutch 5 is closed, connecting the gear ring 13, the gear shift mechanism countershaft 15, and the output component 6 as a whole, transmitting torque to the output component 6 in the second rotation direction; when the motor 4 rotates in the first rotation direction, the speed of the output component 6 is higher than the speed of the gear ring 13, and the second one-way clutch 5 is disengaged, thereby cutting off the power transmission between the gear ring 13 and the output component 6. Preferably, the first rotation direction is the forward rotation direction when the bicycle is moving forward, and the second rotation direction is the opposite direction to the first rotation direction.

[0120] The main shaft 101 is a solid or hollow shaft fixed to the rear fork of the frame, serving as a support shaft for the wheel hub. The freewheel 100 is mounted on the main shaft 101 and is used to mesh with the chain, belt, or drive shaft gear to receive the rider's pedaling power. The planetary carrier 21 is fixedly connected to the freewheel 100. When the freewheel 100 rotates in the first rotation direction, the power is input into the planetary gear assembly 2 through the planetary carrier 21.

[0121] A third one-way clutch 7 is disposed between the flywheel 100 and the ring gear 20 on the manual side, and is used to transmit the power of the flywheel 100 unidirectionally to the ring gear 20 and the output component 6 when needed. The third one-way clutch 7 is configured such that: when the flywheel 100 rotates in a first rotation direction, the third one-way clutch 7 is closed, allowing the torque of the flywheel 100 to be transmitted unidirectionally to the ring gear 20, thereby driving the output component 6; when the speed of the output component 6 is higher than the speed of the flywheel 100, or when the flywheel 100 tends to be in a second rotation direction relative to the output component 6, the third one-way clutch 7 automatically disengages to prevent the rear wheel from generating back drive on the pedal. With the above arrangement, human power can act on the hub through two paths: one is through the flywheel 100 and the planetary carrier 21 into the planetary gear assembly 2; the other is through the flywheel 100 and the third one-way clutch 7 to directly drive the ring gear 20 and the output component 6.

[0122] Similar to Example 2, the hub-mounted electric power-assisted continuously variable transmission (CVT) in this example also has two motor assist modes: power split mode and parallel mode. The working process will be described below under different operating conditions.

[0123] Pure manual mode. When motor 4 is off or not involved in output, the system operates in pure manual mode. In this mode, the rider drives the flywheel 100 to rotate in the first rotation direction via mechanical transmission. The flywheel 100 directly drives the gear ring 20 through the fixedly connected planetary carrier 21 and the third one-way clutch 7, realizing direct output of human power. When the vehicle is coasting at a high speed and the pedal stops, the third one-way clutch 7 can disengage to prevent backdrive.

[0124] Therefore, in pure human power mode, this embodiment is similar to a traditional internal gear hub, with low riding resistance, high transmission efficiency, and no significant return torque from the rear wheel to the pedals.

[0125] Power split mode. Under medium to low load and high speed conditions, the motor 4 can be operated in power split mode through control strategies. The specific process is as follows: The motor 4 drives the sun gear 11 to rotate. After the speed reduction and torque increase through the transmission mechanism 10, the torque output by the motor 4 is transmitted to the sun gear 22 through the transmission mechanism countershaft 15 and the closed first one-way clutch 3, causing the sun gear 22 to rotate in the second rotation direction. At the same time, the rider drives the flywheel 100 to rotate in the first rotation direction through the pedal mechanical transmission, which in turn drives the planetary carrier 21 fixedly connected to it to rotate in the first rotation direction, inputting human power into the planetary gear assembly 2. In the planetary gear assembly 2, the sun gear 22 on the motor side and the planetary carrier 21 on the human side act on multiple planetary gears 23 simultaneously. The planetary gears 23 achieve power coupling between the two, so that the ring gear 20 obtains the superimposed torque and appropriate speed in the first rotation direction, and drives the output component 6 to rotate in the first rotation direction, outputting power to the wheel. Since the rotational speed of the planetary carrier 21 is lower than that of the gear ring 20 at this time, and the output component 6 is driven by the planetary gear assembly 2 via the gear ring 20, the third one-way clutch 7 is in a disengaged state, and the human can participate in power splitting through the path of the planetary carrier 21.

[0126] Parallel mode. When high torque is required for low-speed acceleration or heavy-load driving, motor 4 can be switched to parallel mode. In this mode, control motor 4 to rotate the secondary shaft 15 of the transmission mechanism in the first rotation direction. At this time, the second one-way clutch 5 is engaged, and the first one-way clutch 3 is disengaged.

[0127] The specific process is as follows: The torque output by the motor 4 through the transmission mechanism 10 acts on the transmission mechanism countershaft 15, and is directly transmitted to the output component 6 through the closed second one-way clutch 5, causing the output component 6 to rotate in the first rotation direction; at the same time, the rider drives the flywheel 100 to rotate in the first rotation direction through the pedal, and the flywheel 100 locks and engages with the planetary carrier 21 and the ring gear 20 in the first rotation direction through the third one-way clutch 7, so that the planetary gear assembly 2 forms a rigid body under this working condition, and the ring gear 20, planetary carrier 21 and planetary gear train do not rotate relative to each other. In this state, the human torque and the motor torque are directly connected and superimposed in parallel at the output component 6, the transmission path is short and the number of meshing stages is small, avoiding the loss of power transmitted through the planetary gear, thereby improving the system efficiency under heavy load conditions.

[0128] In summary, the hub-driven continuously variable transmission (CVT) of this embodiment 3 achieves a compact integration of the motor and human power by integrating the transmission mechanism 10, planetary gear set 2, motor 4, and multiple one-way clutches inside the rear wheel hub. The planetary gear set 2 can be equipped with a reducer 10 to reduce the output torque of the motor 4 when needed, thereby allowing the selection of a motor 4 with a higher rated speed to reduce the motor size and improve the compactness of the layout while maintaining the same output torque requirement. Furthermore, through the first one-way clutch 3 and the second one-way clutch 5 arranged on the countershaft 15 of the transmission mechanism, a power splitting path is established from the motor 4 to the sun gear 22 when the sun gear 22 participates in power splitting output, and a parallel path is established from the motor 4 to the output component 6 when the ring gear 20 and the output component 6 are directly driven by the countershaft 15 of the transmission mechanism. In conjunction with the third one-way clutch 7, the flywheel 100 can directly drive the gear ring 20 and the output component 6 when needed, and can automatically disengage when the wheel speed is higher than the pedal speed to prevent back drive. This allows the embodiment to flexibly switch between power split mode and parallel mode according to different working conditions.

[0129] Example 4

[0130] As per the instruction manual Figure 11 Based on Embodiment 1, this embodiment provides a modified version of an electrically assisted continuously variable transmission (CVT). Its overall structure is the same as in Embodiment 1, including a human input component, a central shaft or main shaft and flywheel, a planetary gear set 2, a first one-way clutch 3, a motor 4, a second one-way clutch 5, an output component 6, and a third one-way clutch 7, which respectively constitute the first transmission branch A1, the second transmission branch A2, and the third transmission branch A3. The difference lies in that the planetary gear set 2 consists of two mutually coupled planetary gear sets, namely the first planetary gear set 2-1 and the second planetary gear set 2-2, used to further expand the CVT range and optimize power distribution characteristics. The first planetary gear set 2-1 includes a meshing first sun gear, a first planet carrier, a first ring gear, and first planet gears. The second planetary gear set 2-2 includes a meshing second sun gear, a second planet carrier, a second ring gear, and second planet gears.

[0131] A first transmission branch A1 is provided between the output shaft of motor 4 and the sun gear of the first planetary gear assembly 2-1, and a first one-way clutch 3 is provided on the first transmission branch A1. A second transmission branch A2 is provided between the output shaft of motor 4 and the output component 6, and a second one-way clutch 5 is provided on the second transmission branch A2. A third transmission branch A3 is provided between the manual input component and the output component 6 through the second planetary gear assembly 2-2, and a third one-way clutch 7 is provided on the third transmission branch A3. The manual input component is fixedly connected to the second planetary carrier and is used to input manual power into the second planetary gear assembly 2-2.

[0132] Output component 6 is connected to the first ring gear of the first planetary gear assembly 2-1, and the first ring gear is connected to the second ring gear of the second planetary gear assembly 2-2, so that both the first and second ring gears are used to drive output component 6. The first planet carrier of the first planetary gear assembly 2-1 is connected to the second sun gear of the second planetary gear assembly 2-2. In other implementations, the first ring gear can also be connected to the second sun gear, so that both the first and second sun gears are used to drive output component 6, and the first planet carrier is connected to the second ring gear; this will not be elaborated further here.

[0133] The first one-way clutch 3 is configured such that when the motor 4 rotates in the second rotation direction, the torque of the motor 4 is transmitted to the first sun gear of the first planetary gear assembly 2-1 through the first transmission branch A1 and causes it to rotate in the second rotation direction, the first one-way clutch 3 is in the closed state, and the output of the motor 4 is transmitted unidirectionally to the first sun gear through the first transmission branch A1; when the motor 4 rotates in the first rotation direction, the first one-way clutch 3 is in the disengaged state, thereby cutting off the power transmission between the first transmission branch A1 and the first sun gear.

[0134] The second one-way clutch 5 is configured such that when the motor 4 rotates in the first rotation direction, the torque of the motor 4 is transmitted to the output component 6 through the second transmission branch A2, causing the output component 6 to rotate in the first rotation direction, the second one-way clutch 5 is in the closed state, and the output of the motor 4 is transmitted unidirectionally to the output component 6 through the second transmission branch A2; when the motor 4 rotates in the second rotation direction, the second one-way clutch 5 is in the disengaged state, thereby cutting off the power transmission between the second transmission branch A2 and the output component 6.

[0135] The third one-way clutch 7 is configured such that when the manual input component rotates in the first rotation direction, the third one-way clutch 7 is closed, allowing the manual input component to drive the output component 6 to rotate in the first rotation direction in one direction through the third transmission branch A3 and the second ring gear or the second sun gear of the second planetary gear assembly 2-2 (which is fixedly connected to the first ring gear and the second ring gear or the second sun gear); when the manual input component rotates in the second rotation direction or the speed of the output component 6 is higher than the corresponding speed on the manual side, the third one-way clutch 7 is disengaged, and the manual input component and the output component 6 are disengaged from the linkage.

[0136] In this application, the first rotation direction is the forward direction of the bicycle wheel, and the second rotation direction is the backward direction of the bicycle wheel.

[0137] Taking the connection between the first ring gear of the first planetary gear assembly 2-1 and the second ring gear of the second planetary gear assembly 2-2 as an example: In the power-splitting assist mode, the control system keeps the first transmission branch A1 in operation. The motor power is input to the first sun gear of the first planetary gear assembly 2-1 through the first transmission branch A1, causing the first sun gear to rotate in the second rotation direction; the manual power is input to the second planetary gear assembly 2-2 through the manual input component and the second planetary carrier. The motor side and the manual side mesh with their respective planetary gears inside the first planetary gear assembly 2-1 and the second planetary gear assembly 2-2, respectively, to achieve power coupling. Finally, the power is output through the first ring gear, the second ring gear, and the output component 6, thus forming the power-splitting assist mode. Since the speed of the output component 6 is determined by the speed of the manual input component and the output of the motor 4, a continuously variable transmission function can be achieved.

[0138] In parallel assist mode, the control system keeps the second transmission branch A2 in operation. Motor power is directly input to output component 6 via the second transmission branch A2, causing output component 6 to rotate in the first rotation direction. Simultaneously, manual power is input to the second gear ring of the second planetary gear assembly 2-2 via the third one-way clutch 7, and the second gear ring drives the output component 6, which is fixedly connected to it, for output. The motor power and manual power are output in parallel at output component 6, forming the parallel assist mode.

[0139] The present invention also provides a control method for an electric power-assisted continuously variable transmission (EVV). This control method is applied to the aforementioned EVV, which is suitable for installation at the bottom bracket or wheel hub of a bicycle. The EVV includes a human input component, a planetary gear assembly (sun gear, planet carrier, ring gear, and several planet gears), a first one-way clutch, a second one-way clutch, a motor, an output component, and a third one-way clutch, and has a power-split assist mode and a parallel assist mode.

[0140] Specifically, the control method of this electric power-assisted continuously variable transmission includes:

[0141] Step 1: Obtain vehicle operating condition information.

[0142] Operating condition information includes at least one of the following: vehicle speed, pedal speed and / or pedal torque, road gradient, and battery state of charge.

[0143] The wheel speed signal is obtained by the vehicle speed sensor, which includes a magnet installed on the wheel rim and Hall sensors fixedly installed at corresponding positions on the rear and front forks. The wheel speed signal can also be obtained indirectly through the motor position sensor. That is, when the motor and the wheel are arranged coaxially in the wheel hub, the controller calculates the wheel speed based on the motor Hall signal.

[0144] The pedal speed signal is obtained by a pedal frequency sensor, which includes a magnetic ring or magnet mounted on the bottom bracket assembly, and a Hall sensor fixedly mounted on the outside of the bottom bracket housing of the frame. The Hall sensor outputs a pulse signal, and the controller calculates the pedal speed signal based on the pulse frequency.

[0145] The manual input torque signal is obtained by a torque sensor, which is a strain gauge torque sensor installed at the central shaft. The controller calculates the manual input power signal based on the manual input torque signal and the pedal speed signal.

[0146] The motor speed signal is acquired by a motor position sensor, which is a motor Hall element and / or encoder, and is located on the stator side of the motor inside the hub or in the motor detection circuit of the controller. The motor output torque signal can be estimated by the motor controller based on the phase current signal. The current signal is acquired by a current sampling element installed in the controller's power circuit, such as a shunt resistor or a Hall current sensor. The motor voltage signal is acquired by the controller through a voltage sampling circuit.

[0147] The battery's state of charge (SOC, or remaining battery capacity, expressed as a percentage from 0% to 100%, e.g., SOC=60% means the battery has approximately 60% usable capacity) and / or capacity signal are acquired by the battery management system (BMS). The BMS calculates the SOC based on battery voltage, current, and / or temperature information and sends it to the controller.

[0148] The gradient signal and / or longitudinal acceleration signal are acquired by an inertial measurement unit (IMU), which is fixedly installed inside the frame controller housing, in the center mount of the frame, or in the controller cavity near the rear wheel hub. The braking signal is acquired by a switch or pressure sensor installed at the brake lever.

[0149] Step 2: When the operating condition information determines that the current condition is a start-up, low-speed, and / or medium-to-small load demand condition, the control motor outputs in the direction of the first transmission branch A1 to drive the first one-way clutch to close. The motor power is input to the sun gear of the planetary gear assembly through the first transmission branch. The second one-way clutch disengages, cutting off the direct transmission of motor power to the output component. At the same time, the manual input component is allowed to input manual power into the planetary gear assembly through the fixedly connected planetary carrier. This causes the motor power and manual power to be split within the planetary gear assembly and combined at the gear ring. The output is then generated by the gear ring and the output component connected to it, forming a power splitting assist mode.

[0150] Specifically, from the operating condition information obtained in step 1, at least one or a combination of the following features should be extracted: vehicle speed. Or wheel speed Foot pedal speed Manual input torque and / or human input power longitudinal acceleration of vehicles ,slope Motor current and braking signal When at least one of the following starting conditions, low-speed conditions, and / or high torque demand conditions is met, the current condition is determined to be a starting, low-speed, and / or medium-to-small load demand condition.

[0151] Among them, any one of the following starting conditions must be met: 1. or and and 2. or and and 3. or and and . The starting speed threshold, The recommended speed is 0-5 km / h, with 1-3 km / h being the preferred speed. The starting wheel speed threshold, i.e., with The starting wheel speed threshold calculated based on the effective wheel circumference . This is the lower limit threshold for starting cadence, used to confirm that someone is pedaling and to avoid false triggering. It can be set to 5-30 rpm, with 10-20 rpm being preferred. The starting torque threshold is used to confirm a clear intention to pedal and the force applied at the start, and can be taken as 10%-35% of the rated torque. The starting longitudinal acceleration threshold is used to identify the transient state at the start of acceleration. It can be 0.02-0.10g, preferably 0.03-0.06g.

[0152] The low-speed condition only needs to meet any one of the following: 1. or ≤ 2. and It is used to identify low cadence and low speed to prevent misjudgment. The first low-speed threshold is the upper limit of the low speed for which power splitting is applicable. It is still biased towards the lower low-speed section and can be taken as 5-12km / h, with 5-8km / h being preferred. The first low-speed wheel speed threshold, and Equivalent. The first low cadence threshold can be set to 30-60 rpm, with 40-60 rpm being preferred.

[0153] For small to medium load requirements, any one of the following conditions must be met: 1. Manually input torque. and / or human input power 2. 3. Uphill driving with low resistance; This indicates that the motor is operating under medium to small load output requirements. To switch from power shunt to parallel direct drive, the high torque threshold on the pedal side can be 40%-70% of the rated human torque. The power threshold for switching from power shunt to parallel direct drive can be set to 150-300W, which can be adjusted according to vehicle type and user group. The slope threshold for switching from power shunt to parallel direct drive can be 3%-8%, approximately 1.7°-4.6°. For motors switching from power shunt to parallel direct drive, the high load current threshold can be set to 60%-90% of the motor current limit value.

[0154] Step 3: When the operating condition information indicates that the current condition is low speed and high load demand, the control motor outputs in the direction of the second transmission branch A2 to drive the second one-way clutch to close. The motor power is directly input to the output component through the second transmission branch. The first one-way clutch disengages, cutting off the input of motor power to the sun gear. At the same time, the manual input component is allowed to input manual power to the output component through the third one-way clutch and the gear ring of the planetary gear assembly. This allows the motor power and manual power to be combined in parallel at the output component to form a parallel assist mode.

[0155] Specifically, from the operating condition information obtained in step 1, at least one or a combination of the following features should be extracted: vehicle speed. Or wheel speed Foot pedal speed Manual input torque and / or human input power longitudinal acceleration of vehicles ,slope Motor current and braking signal When both the following low-speed conditions and high-load demand conditions are met simultaneously, the current operating condition is determined to be low-speed, high-load demand.

[0156] Among them, any one of the low-speed conditions needs to be met: or . This is the second low-speed threshold, which is the upper limit of the low speed applicable to the parallel mode, and is higher than that in step 2. The recommended speed range is 12-22 km / h, with 12-16 km / h being the preferred speed. The second low-speed wheel speed threshold, and Equivalent.

[0157] Any one of the following conditions must be met for high load demand: 1. ≥ This indicates a continuous high load output demand from the motor; 2. ≥ and / or ≥ 3. This indicates that the cyclist is continuously applying significant force; Indicates uphill working condition; 4. When v≤ Under the conditions, if ≤ and or If the load consistently exceeds its respective threshold, it is determined to be a high-load demand that is difficult to accelerate at low speeds, which is used to identify non-slope scenarios such as headwinds, heavy loads, and muddy terrain. For continuous high load current threshold in parallel mode, it can be taken as 50%-85% of the motor current limit value. The threshold for manual torque in parallel mode can be 25%-55% of the rated manual torque. The power threshold for parallel operation can be set to 120-260W. The slope threshold for parallel mode can be set to 5%-12%. The minimum acceleration threshold for parallel mode can be 0-0.05g, preferably 0.01-0.03g.

[0158] Step 4: When it is determined based on the operating condition information that electric assist is not needed or the battery power is lower than the preset threshold, the motor is controlled to stop outputting, so that the motor output shaft is in an idling state. Only the human input component is allowed to drive the output component through the planetary carrier and / or the third one-way clutch, thus forming a pure human riding mode.

[0159] Specifically, from the operating condition information obtained in step 1, at least one or a combination of the following features should be extracted: vehicle speed. Or wheel speed Foot pedal speed Manual input torque and / or human input power longitudinal acceleration of vehicles ,slope Motor current and braking signal The system enters pure human-powered riding mode when at least one of the following conditions—either no electric assist required or low battery—is met.

[0160] No electric assist is required if any one of the following conditions is met: 1. The assist mode selection signal indicates no assist and assist off, i.e. 2. The braking signal is valid, that is... It is preferable to immediately cut off the electric assist.

[0161] Low battery condition: Any one of the following conditions must be met: 1. Battery state of charge. 2. Battery voltage It is used for protection determination when there is no SOC or the SOC is unreliable. The low battery threshold is used to determine whether the remaining available battery power is insufficient to continue providing electric assistance or whether a protection and energy-saving strategy needs to be activated. It can be set to 5%-20%, preferably 10%-15%. This is the low voltage threshold for the battery, used to determine insufficient power or trigger undervoltage protection based on the battery terminal voltage when the SOC is unavailable or the estimation is unreliable. It can be set to 95%-100% of the battery's cutoff discharge voltage.

[0162] Step 5: Repeat Step 1 in real time, and switch between power shunt assist mode, parallel assist mode and pure manual mode according to the updated operating condition information.

[0163] The above descriptions are merely embodiments of this application, and common knowledge regarding specific structures and characteristics in the solutions is not described in detail here. It will be apparent to those skilled in the art that this application is not limited to the details of the above exemplary embodiments, and that this application can be implemented in other specific forms without departing from the spirit or essential characteristics of this application. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of this application is defined by the appended claims rather than the foregoing description. Therefore, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this application. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. An electrically assisted continuously variable transmission (CVT), characterized in that, include: Manual input components; The planetary gear assembly (2) includes a sun gear, a planet carrier, a gear ring, and several planet gears that mesh with each other; Motor (4); Output component (6); The first transmission branch connects the output of the motor (4) to the sun gear of the planetary gear assembly (2), and the first transmission branch is provided with a first one-way clutch (3), which is configured to allow only the torque of the motor (4) to be transmitted to the sun gear along the first transmission branch and to disengage when transmitted in the reverse direction. The second transmission branch connects the output of the motor (4) to the output member (6), and the second transmission branch is provided with a second one-way clutch (5). The second one-way clutch (5) is configured to allow only the torque of the motor (4) to be transmitted to the output member (6) along the second transmission branch and to disengage when transmitted in the reverse direction. The third transmission branch is provided between the human input component and the output component (6) via the planetary gear assembly (2), and the third transmission branch is provided with a third one-way clutch (7). The third one-way clutch (7) is configured to allow torque to drive the output component (6) to rotate via the third transmission branch and the ring gear of the planetary gear assembly (2) when the human input component is driven in the first rotation direction, and to disengage when the human input component is driven in the second rotation direction opposite to the first rotation direction, so as to decouple the human input component and the output component (6). The human input component is connected to the planet carrier of the planetary gear assembly (2) via a transmission, and the output component (6) is connected to the gear ring of the planetary gear assembly (2) via a transmission.

2. The electrically assisted continuously variable transmission according to claim 1, characterized in that, The electric continuously variable transmission (CVT) is a centrally mounted type, located at the bottom bracket position of the bicycle frame. The human input component is the central shaft (1). The CVT also includes a housing (9) and a countershaft assembly (8). The housing (9) is fixedly mounted on the bicycle frame. The central shaft (1) is rotatably connected to the housing (9) via bearings. The planetary gear assembly (2) is fixedly connected to the central shaft (1) via a planetary carrier. The planetary gear assembly (2), motor (4), first one-way clutch (3), second one-way clutch (5), third one-way clutch (7), and countershaft assembly (8) are located inside the housing (9). The countershaft assembly (8) contains... The assembly includes a secondary shaft input gear (80), a secondary shaft (81), a first secondary shaft output gear (82), and a second secondary shaft output gear (83). The secondary shaft (81) is rotatably connected to the housing (9), and the secondary shaft (81) is fixedly connected to the secondary shaft input gear (80) to rotate synchronously with the secondary shaft input gear (80). The first secondary shaft output gear (82) is coaxially arranged with the secondary shaft (81) and is sleeved on the secondary shaft (81) via the first one-way clutch (3). The second secondary shaft output gear (83) is coaxially arranged with the secondary shaft (81) and is sleeved on the secondary shaft (81) via the second one-way clutch (5).

3. The electrically assisted continuously variable transmission according to claim 2, characterized in that, The planetary gear assembly (2) further includes a planetary gear input gear (220) and a coupling gear (200). The motor (4) is provided with a motor output gear (410) that meshes with the secondary shaft input gear (80). The first secondary shaft output gear (82) is connected to the sun gear of the planetary gear assembly (2) via the planetary gear input gear (220). The second secondary shaft output gear (83) is connected to the gear ring of the planetary gear assembly (2) and the output member (6) via the coupling gear (200).

4. The electrically assisted continuously variable transmission according to claim 1, characterized in that, The electric continuously variable transmission is a hub type, located at the rear wheel hub of the bicycle and integrated inside the hub. The human input component is a flywheel (100) set on the main shaft (101). The main shaft (101) is fixed to the rear fork of the frame. The output component (6) is rotatably connected to the main shaft (101) through a bearing. The flywheel (100) is sleeved on the main shaft (101) and rotatably connected to the main shaft (101) through a bearing. The planet carrier of the planetary gear assembly (2) is fixedly connected to the flywheel (100), and the gear ring of the planetary gear assembly (2) is fixedly connected to the output component (6).

5. The electrically assisted continuously variable transmission according to claim 4, characterized in that, The electric power-assisted continuously variable transmission also includes a speed change mechanism (10) disposed between the motor (4) and the planetary gear assembly (2). The planetary gear assembly (2), the motor (4), the first one-way clutch (3), the second one-way clutch (5), the third one-way clutch (7) and the speed change mechanism (10) are disposed inside the housing of the output component (6).

6. The electrically assisted continuously variable transmission according to claim 5, characterized in that, The transmission mechanism (10) includes a transmission sun gear (11), multiple transmission planet gears (12), a transmission ring gear (13), a transmission planet carrier (14), and a transmission mechanism countershaft (15). The multiple transmission planet gears (12) are mounted on the transmission planet carrier (14) and mesh with the transmission sun gear (11). The transmission ring gear (13) meshes with the multiple transmission planet gears (12). The transmission planet carrier (14) is fixedly connected to the main shaft (101). The transmission ring gear (13) is fixedly connected to the transmission mechanism countershaft (15).

7. The electrically assisted continuously variable transmission according to claim 6, characterized in that, The first one-way clutch (3) is disposed between the secondary shaft (15) of the transmission mechanism and the sun gear of the planetary gear assembly (2), and the inner ring of the first one-way clutch (3) is connected to the sun gear of the planetary gear assembly (2) and the outer ring is connected to the secondary shaft (15) of the transmission mechanism; the second one-way clutch (5) is disposed between the secondary shaft (15) of the transmission mechanism and the output member (6), and the inner ring of the second one-way clutch (5) is connected to the secondary shaft (15) of the transmission mechanism and the outer ring is connected to the output member (6); the third one-way clutch (7) is disposed between the flywheel (100) and the gear ring of the planetary gear assembly (2).

8. The electrically assisted continuously variable transmission according to claim 1, characterized in that, The electric power-assisted continuously variable transmission (CVT) has a pure manual mode, a power-split assist mode, and a parallel assist mode. Through the engagement and disengagement of the first one-way clutch (3), the second one-way clutch (5), and the third one-way clutch (7), the following power transmission paths are formed respectively: In the pure manual mode, the motor (4) does not output driving torque, and the first one-way clutch (3) and the second one-way clutch (5) are in an overrunning disengagement state; the torque of the manual input component is transmitted unidirectionally to the gear ring through the third one-way clutch (7) of the third transmission branch, and the gear ring drives the output component (6). In the power split assist mode, the torque of the motor (4) is transmitted to the sun gear of the planetary gear assembly (2) via the first transmission branch and the first one-way clutch (3), and the torque of the human input component is input to the planet carrier of the planetary gear assembly (2) via the third transmission branch. The motor torque and the human torque are coupled in the planetary gear assembly (2) and then output by its ring gear to drive the output component (6); wherein the second one-way clutch (5) is in the overrunning disengagement state to block the power transmission of the motor (4) to the output component (6) via the second transmission branch; In the parallel assist mode, the torque of the motor (4) is transmitted to the output component (6) via the second transmission branch and the second one-way clutch (5), while the torque of the manual input component is transmitted to the ring gear of the planetary gear assembly (2) via the third transmission branch and the third one-way clutch (7) and drives the output component (6), so as to form a parallel drive of the output component (6) by the manual branch and the motor branch.

9. The electrically assisted continuously variable transmission according to claim 1, characterized in that, The planetary gear assembly (2) includes two mutually coupled planetary gears, namely a first planetary gear assembly (2-1) and a second planetary gear assembly (2-2). The first planetary gear assembly (2-1) includes a first sun gear, a first planet carrier, a first ring gear, and a plurality of first planet gears that mesh with each other. The second planetary gear assembly (2-2) includes a second sun gear, a second planet carrier, a second ring gear, and a plurality of second planet gears that mesh with each other. The first transmission branch connects the output shaft of the motor (4) to the first sun gear of the first planetary gear assembly (2-1). The second transmission branch connects the output shaft of the motor (4) to the output component (6). The third transmission branch is located between the human input component and the output component (6) via the second planetary gear assembly (2-2). The human input component is fixedly connected to the second planet carrier, and the output component (6) is drivenly connected to the first ring gear. The first one-way clutch (3) is located on the first transmission branch, the second one-way clutch (5) is located on the second transmission branch, and the third one-way clutch (7) is located on the third transmission branch. The first gear ring is driven to the second gear ring or the second sun gear: when driven to the second gear ring, the first gear ring and the second gear ring drive the output component (6) together, and the first planet carrier is driven to the second sun gear; when driven to the second sun gear, the first gear ring and the second sun gear drive the output component (6) together, and the first planet carrier is driven to the second gear ring.

10. A control method for an electrically assisted continuously variable transmission (CVT) as described in any one of claims 1-9, characterized in that, The control method includes: Step 1: Obtain vehicle operating condition information; Step 2: When the operating condition information determines that the current condition is a start-up, low-speed and / or medium-to-small load demand condition, the control motor outputs the first one-way clutch in the direction of the first transmission branch and the motor power is input to the sun gear of the planetary gear assembly through the first transmission branch. The second one-way clutch disengages, cutting off the direct transmission of motor power to the output component. At the same time, the manual input component is allowed to input manual power into the planetary gear assembly through the fixedly connected planetary carrier, so that the motor power and manual power are split in the planetary gear assembly and combined at the gear ring. The output is then output by the gear ring and the output component connected to it, forming a power splitting assist mode. Step 3: When the operating condition information indicates that the current condition is low speed and high load demand, the control motor outputs the second one-way clutch in the direction of the second transmission branch and closes the second one-way clutch. The motor power is directly input to the output component through the second transmission branch. The first one-way clutch disengages, cutting off the input of motor power to the sun gear. At the same time, the manual input component is allowed to input manual power to the output component through the third one-way clutch and the gear ring of the planetary gear assembly. This allows the motor power and the manual power to be combined in parallel at the output component to form a parallel assist mode. Step 4: When it is determined based on the operating condition information that electric assistance is not needed or the battery power is lower than the preset threshold, the motor is controlled to stop output, so that the motor output shaft is in an idling state. Only the human input component is allowed to drive the output component through the planetary carrier and / or the third one-way clutch, thus forming a pure human riding mode. Step 5: Repeat Step 1 in real time, and switch between power shunt assist mode, parallel assist mode and pure manual mode according to the updated operating condition information.

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