Under the influence of the international epidemic, the bicycle market has shown a rare contrarian growth in recent years, and domestic upstream and downstream factories have followed overtime to produce and export. Among them, the rapid growth is electric bicycles. We can foresee In the next few years, electric-assisted bicycles will inevitably become a new growth point in the domestic bicycle field.
Electric-assisted bicycles, broadly speaking, are electric-assisted bicycles, which are different from pure electric electric bicycles or electric bicycles. They still need to be driven by human pedaling. The motor only plays an auxiliary role. It assists the bicycle under rated conditions. , Making riding easier, improving overall endurance and reducing riding difficulty. From the first electric-assisted commuter vehicles to today’s electric-assisted mountain bikes, road bikes, and Gravel vehicles, the electric-assisted system has been developed technically and can be fully adapted to the vehicle model. We can see that whether it is ordinary The hard-tail XC, the more heavier forest road cross-country or road bike, all have the shadow of electric power. I myself have experienced different stages of development and different forms of electric assist products in my long-term cycling experience, so I would like to share with you briefly.
The external manifestations of electric power assistance can be roughly divided into wheel drive (Hub Drive) and mid drive (Mid Drive).
In the early years, due to design concepts and body structure reasons, some commuter and touring vehicles adopted the form of front-wheel drive (such as Panasonic’s single-speed commuter car in Japan and Xiaomi’s electric-assisted folding car). It is integrated into the hub and converts electrical energy into mechanical energy after being energized. This method has a relatively simple structure and low cost. It is also one of the main forms of refitting electric bicycles on the market.
However, there are many problems caused by front-wheel drive. The first problem is weight. The front wheels are bulky and heavier. The increase in weight of the front wheels by a few kilograms will have a greater impact on daily control; the second problem is resistance. , The wheel motor will increase the riding resistance when the battery is out of power, combined with its own weight, will affect the riding experience; the third problem is adaptability, the front wheel motor needs the manufacturer to prepare the wheel set, if it is an ordinary commuter bike, it is not necessary to replace it. It’s not a big problem, but if it’s a high-end sports bike, the wheel set prepared by the manufacturer has shortcomings in terms of grade and adaptation; in addition, the weight and driving force of the front wheel motor will increase the front brake. Pressure increases brake loss, and some safety problems may occur in severe cases; wheel motors do not have an advantage in terms of energy consumption. Therefore, it is reasonable that this type of drive has not been widely promoted in sports bikes.
In the early years, due to design concepts and body structure reasons, some commuter and touring vehicles adopted the form of front-wheel drive (such as Panasonic’s single-speed commuter car in Japan and Xiaomi’s electric-assisted folding car). It is integrated into the hub and converts electrical energy into mechanical energy after being energized. This method has a relatively simple structure and low cost. It is also one of the main forms of refitting electric bicycles on the market.
However, there are many problems caused by front-wheel drive. The first problem is weight. The front wheels are bulky and heavier. The increase in weight of the front wheels by a few kilograms will have a greater impact on daily control; the second problem is resistance. , The wheel motor will increase the riding resistance when the battery is out of power, combined with its own weight, will affect the riding experience; the third problem is adaptability, the front wheel motor needs the manufacturer to prepare the wheel set, if it is an ordinary commuter bike, it is not necessary to replace it. It’s not a big problem, but if it’s a high-end sports bike, the wheel set prepared by the manufacturer has shortcomings in terms of grade and adaptation; in addition, the weight and driving force of the front wheel motor will increase the front brake. Pressure increases brake loss, and some safety problems may occur in severe cases; wheel motors do not have an advantage in terms of energy consumption. Therefore, it is reasonable that this type of drive has not been widely promoted in sports bikes.
Compared with the front wheel motor, the structure of the rear wheel motor is more complicated. It also needs to consider the transmission system such as the tower base flywheel. Therefore, the cost is higher. However, the rear wheel motor also has some shortcomings that are difficult to overcome. The first is the integrity. It is difficult to find a rear-wheel motor that can be modified and matched with brand wheels on the market. Therefore, it still needs a wheel set prepared by the manufacturer. This is very inconvenient for the adaptability of different models, and it is also necessary for the later upgrade of the wheel set. At the same time, the weight problem of the front-wheel motor still exists on the rear-wheel motor. The rear-wheel motor drive is prone to skidding in certain environments, and it will still bring greater riding resistance when it is out of power. The motor is located at the wheel set position, which will affect the life span under long-term vibration or harsh working conditions.
In these three forms, the mid-mounted motor is undoubtedly the optimal solution. Although the mid-mounted motor also has a relatively large weight, placing it on the bottom bracket of the frame will not affect the counterweight of the front and rear wheels, and it can also reduce the center of gravity. At the same time, the center-mounted motor often uses a clutch transmission gear. It can automatically cut off the connection between the motor and the transmission system when stepping on or when the battery is dead, so it will not cause additional resistance. Compared with wheel motors, electric bicycles with mid-mounted motor systems can freely replace wheel sets, and later upgrades will not be affected. It can be said that the mid-mounted motor represents the technical direction of the electric assist system in sports bicycles, and is an antidote to the structural problems of sports electric bicycles. Therefore, it is also a strategic place for major brands to scramble for research.
For consumers, what brand of electric power assistance they choose nowadays is actually not "selecting a car", but selecting an electric power assistance system. Limited by the appearance, the mid-mounted motor often needs to be deeply bound to the frame. There is still no unified appearance specification or international standard, so it is difficult for us to evaluate different motor systems on the same starting line. Therefore, I also hope that the domestic motor manufacturers can unite internally to determine the internal "national standard" standard appearance of an industry. This way, it will be easier for the OEMs to design the frame, and for the upstream and downstream parts manufacturers. It is also more imaginative, and at the same time, it can also force major foreign brands to consider unified standards.
Post time: Sep-09-2021
