Electric bicycles can be divided into two categories: all-electric and smart-assist.
(1) All-electric bicycles: You can ride on the pedals, or you can drive by pure electric power without manpower, and use the handlebars to control the speed to achieve a stepless speed change of 0-20 kilometers per hour.
(2) Intelligent power-assisted electric bicycle: It has a similar operation mode to that of ordinary bicycles. It can be driven by human power or powered by electricity. It has no pure electric function. It is mainly based on human power and supplemented by electricity. The size of the human riding force is controlled by the size of the current supply, so as to realize the combination of human power and electric power, and the riding feels relaxed. When the design speed is reached, Shenli stops supplying.
Basic composition of electric bicycle:
Electric bicycles are composed of five parts: body, electric drive (motor), rechargeable battery, charger and control system. Different types of vehicles have different battery placement positions and controller forms.
(1) Body: As the national standard stipulates that the electric drive mode of electric bicycles generally has three categories:
①Friction transmission type: The dry tire is directly loaded by the wheel on the motor shaft, and is driven by friction. It has the advantages of simple structure and low cost, but the tire wears a lot, and it is easy to slip in the rainy season.
②Central axle drive type: The electric motor is specially designed at the central axle of the frame, and the central axle is driven by the deceleration mechanism, and then the central axle drives the rear wheel through the chain. The advantage is that the center of gravity of the machine is reasonable, and it can use the bicycle deceleration system to shift gears, and the old machinery has a large loss.
③Electric hub type: The motor is installed in the hub of the wheel, which can be installed in the front wheel or the rear wheel. The hub is connected with the rim by the spokes, which directly drives the wheel to rotate. Its advantages are small size, light weight, low energy consumption and high efficiency, but it is difficult to dissipate heat from the motor and lubricate the transmission gear. At present, most domestic electric bicycles are in this way.
Motors are divided into two categories: brushless motors and brushed motors. The brushless motor is mainly a low-speed and high-torque motor, without transmission gear, which avoids mechanical wear and almost no noise during operation, but the brushless motor has a large impact on the starting current, and the control system has a complex structure. Brush life, high motor efficiency, simple control system electronic circuit.
(2) Rechargeable batteries: There are three main types of batteries used in electric bicycles, namely small sealed maintenance lead-acid batteries, nickel-cadmium batteries and nickel-hydrogen batteries. Small sealed maintenance-free lead-acid batteries with low cost and large capacity are widely used by domestic enterprises.
(3) Charger: The charger design adopts three-stage automatic conversion method of current, pressure and floating charge, which protects the battery and effectively prolongs the battery life.
(4) Control system: The control system is designed with a number of protection functions, such as power display, stepless speed regulation, soft start, undervoltage protection, overcurrent protection and brake power failure. Protect the motor and the battery, so that the current can be output effectively to generate the required power without burning the motor. At present, most of the electric bicycles developed in China use the manual speed control handle to determine the power supply method by themselves.
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