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CN-121973568-A - Electric control stepless speed change hub of bicycle and automatic stepless speed change control method

CN121973568ACN 121973568 ACN121973568 ACN 121973568ACN-121973568-A

Abstract

The invention discloses an electric control stepless speed change hub of a bicycle, which comprises a hub shell and a planetary transmission mechanism arranged in the hub shell, wherein the planetary transmission mechanism comprises a planet carrier, a sun gear, a gear ring and a planetary gear, the planet carrier is in transmission connection with a flywheel of the bicycle to serve as a first input end, the gear ring is fixedly connected with the hub shell to serve as an output end, and the sun gear is connected with a speed regulation driving mechanism to serve as a second input end. The inside of the hub is provided with a speed measuring code wheel and a speed measuring sensor which are used for acquiring the rotating speed and the output rotating speed of the planet carrier and sending the rotating speed to the controller. The controller controls the speed-adjusting driving mechanism based on the riding state, realizes automatic speed change under different working conditions, and enables the system to maintain a passive transmission state capable of riding under the power-off state. The invention has continuous speed change, compact structure and stable control, and is suitable for the fields of bicycles and electric power-assisted bicycles.

Inventors

  • YIN ZHANG
  • DENG RIYANG

Assignees

  • 特宙斯(深圳)科技有限公司

Dates

Publication Date
20260505
Application Date
20251231

Claims (10)

  1. 1. An electrically controlled continuously variable transmission hub for a bicycle, comprising: A hub shell; The planetary transmission mechanism is arranged in the hub shell and comprises a planet carrier, a sun gear, a gear ring and a planet gear arranged between the planet carrier and the gear ring; The bicycle flywheel is in transmission connection with the planet carrier through a one-way bearing or a ratchet wheel and is used for inputting the pedaling power of a rider to the planet carrier, and the one-way bearing or the ratchet wheel does not drive the flywheel to rotate when the wheel rotates; the gear ring is fixedly connected with the hub shell and serves as a power output end of the hub; the speed regulation driving mechanism is connected with the sun gear and used for driving the sun gear to rotate at a controllable rotating speed and in a steering way; the controller is electrically connected with the speed regulation driving mechanism; The planet carrier is used as a first input end, the sun gear is used as a second input end, and under the condition that the input rotation speed of the planet carrier is unchanged, the rotation speed or the rotation direction of the sun gear is controlled, so that the output rotation speed of the gear ring is continuously changed, and stepless speed change is realized.
  2. 2. The electrically controlled continuously variable transmission hub of a bicycle of claim 1, wherein the planetary transmission mechanism is an NGW type planetary gear mechanism, and the planet carrier, the sun gear and the gear ring are coaxially arranged; at least two speed measuring code discs and at least one speed measuring sensor are arranged in the hub, wherein, The first speed measuring code disc is arranged at an output side position linked with the gear ring or the hub shell and used for reflecting the output rotating speed of the hub; the second speed measuring code wheel is arranged at the input side position linked with the planet carrier or the flywheel and used for reflecting the rotation speed of the planet carrier and detecting the input rotation speed of manpower; The speed measuring sensor is fixedly arranged in the hub shell and is configured to detect the rotating speed of the two speed measuring code discs, The detected rotation speed signal is sent to the controller for stepless speed change control and state identification.
  3. 3. The electrically controlled stepless speed change hub of bicycle of claim 1, wherein the speed regulating driving mechanism comprises a speed regulating motor and a speed reducing mechanism connected with the output end of the speed regulating motor, and the output end of the speed reducing mechanism is fixedly connected with the sun gear.
  4. 4. The electrically controlled stepless speed change hub for bicycles, according to claim 3, wherein said speed regulating motor is a permanent magnet synchronous motor or a torque motor or a brush motor.
  5. 5. The electrically controlled stepless speed change hub for bicycle of claim 1, wherein a relay assembly is arranged between the controller and the speed regulating motor, and in a system power-off state, the relay assembly enables multiphase windings of the speed regulating motor to form a short circuit state, so that the hub can maintain a passive transmission state capable of being ridden under the condition of no electric control.
  6. 6. The electrically controlled continuously variable hub of claim 1, wherein the controller is configured to reverse the pedaling torque applied to the planet carrier by the rider by detecting the phase current of the speed motor.
  7. 7. The electrically controlled continuously variable hub of a bicycle of claim 1, wherein the controller is configured to calculate a pedaling frequency of a rider by detecting a rotational speed of the ring gear and a rotational speed of the speed regulating motor.
  8. 8. An automatic stepless speed change control method based on the electrically controlled stepless speed change hub of the bicycle according to any one of claims 1 to 7, which is characterized by comprising the following steps: Collecting the trampling frequency of a rider and the rotating speed of the planet carrier; Based on the trampling frequency and the rotating speed of the planet carrier, a finite state machine is constructed, and the riding process is divided into a starting state, a riding state and a braking state; Under different states, corresponding target sun gear rotating speed instructions are generated, and the speed regulating driving mechanism is controlled to drive the sun gear to rotate, so that the automatic adjustment of the hub speed ratio is realized.
  9. 9. The automatic continuously variable transmission control method according to claim 8, wherein in the start-up state, when the stepping frequency is detected to be larger than the first preset threshold value, the closed-loop control is started, and the target carrier rotation speed is gradually increased with a preset slope until the set value is reached.
  10. 10. The automatic continuously variable transmission control method according to claim 8, wherein in the riding state, the carrier rotation speed is set as a control target, and the target sun gear rotation speed is generated by multi-stage closed-loop control so that the carrier rotation speed is stabilized within a target range; and under the braking state, the closed-loop control is disconnected, the target solar wheel rotating speed and the planet carrier rotating speed synchronously drop, and the starting state is switched after the planet carrier rotating speed is zero.

Description

Electric control stepless speed change hub of bicycle and automatic stepless speed change control method Technical Field The invention relates to the field of bicycle electric control, in particular to an electric control stepless speed change hub of a bicycle and an automatic stepless speed change control method. Background A bicycle is a vehicle mainly driven by manpower, and the running process of the bicycle is essentially to convert the pedaling force of a rider into wheel rotation through a transmission system. Because of the road condition, the speed and the physical state change of the rider in the riding process, a single fixed transmission ratio is difficult to take into account various working conditions such as starting, accelerating, cruising, climbing and the like, a speed change system becomes an important component part of a modern bicycle, in particular an electric power bicycle. The existing bicycle speed change system mainly comprises an outer speed change system and an inner speed change hub system. The external speed change system generally switches transmission paths between chain wheels or flywheels with different sizes through front and rear derailleurs, so that the speed ratio is changed, the system is relatively simple in structure and high in transmission efficiency, but the problems of exposure to the outside, easiness in pollution, frequent maintenance, obvious gear shift impact and the like exist, and on an electric booster bicycle, frequent gear shift easily impacts transmission parts, and the reliability of the whole bicycle is affected. In comparison, the internal speed change hub integrates the speed change mechanism inside the hub, has the advantages of compact structure, good protection, low maintenance and the like, and is widely applied to urban commuter vehicles and electric power assisted bicycles. The prior internal gear shifting hub on the market mainly adopts a multistage planetary gear structure, a plurality of planetary reduction stages with different transmission ratios are arranged in the hub, and the gears are switched among different transmission stages through clutches, pawls or actuators, so that the gear shifting with limited gears is realized. The essence of the scheme still belongs to discrete gear speed change, not only is the number of gears limited, but also transmission interruption or torque abrupt change is inevitably generated in the gear switching process, and riding smoothness is affected. To achieve a smoother shifting experience, some products propose so-called continuously variable shifting schemes, for example continuously adjusting the speed ratio by changing the effective transmission radius by means of friction elements. However, such schemes generally rely on friction to transmit torque, and have limited bearing capacity, are difficult to adapt to larger riding torque demands, and have complex structure, large weight, high cost, and difficult to ensure long-term reliability, so that the application in the field of bicycle hubs is greatly limited. From the perspective of a planetary transmission structure, a traditional internal variable-speed hub generally fixes one component among a planet carrier, a sun gear and a gear ring, the other component is taken as an input, the other components are taken as outputs, and different transmission ratios are realized by changing meshing paths or locking relations. Under the technical route, the planetary transmission system always has only one effective input end, the speed ratio change of the planetary transmission system can only be switched by a structure or regulated by friction, and the continuous stepless speed change in the true sense is difficult to realize while the structure is kept simple and the reliability is high. On the other hand, with the popularization of electric power assisted bicycles, the problem of matching between the transmission system and the power assisted system is increasingly prominent. In the existing electric power-assisted bicycle, a speed changing system and a motor power-assisted system often work independently, power-assisted control is usually carried out based on pedal frequency, pedal force or vehicle speed, and gear change of the speed changing system cannot be fed back to the power-assisted system in real time. When the gear is changed, the power-assisted output cannot be synchronously adjusted, abrupt torque change or mismatching of pedaling frequency is easily caused, a rider needs to frequently and manually intervene in speed change or adjust pedaling force, riding burden is increased, riding experience is affected, and even adverse effects are caused on the durability of a transmission system. To reduce the complexity of rider operation, some products incorporate automatic shifting strategies, such as automatic shifting based on vehicle speed or wheel speed. However, most of the automatic speed changing schemes are still based on discrete gear structure