Composition of bicycle

System structure

Among the 25 components of bicycle frame, tire, pedal, brake and chain, the basic components are indispensable. Among them, the frame is the skeleton of the bicycle, which bears the largest weight of people and goods. According to the working characteristics of each component, it can be roughly divided into guiding system, driving system and braking system:

1. Guiding system: it is composed of handlebars, front forks, front axles, front wheels and other components. The rider can change the driving direction and maintain the body balance by manipulating the handlebar.

2. Drive (transmission or walking) system: it is composed of pedal, central shaft, tooth disc, crank, chain, flywheel, rear axle, rear wheel and other components. The pedal force of people's feet is driven by the pedal through crank, sprocket, chain, flywheel, rear axle and other parts, so as to make the bicycle move forward continuously.

3. Braking system: it is composed of brake components. Riders can operate the brake at any time to slow down and stop the running bicycle and ensure driving safety.

In addition, in order to be safe, beautiful and practical, it is also equipped with lights, brackets, bells and other components.

form

1. Body part: including

Bicycle photos

Bicycle photos (11)

Frame, front fork, handlebar, saddle and front fork assembly are the main body of bicycle. The transmission part includes pedals, cranks, sprockets, chains, central shafts, flywheels, etc. the pedals are manually stepped on, and the wheels are driven to rotate and drive forward through the above transmission parts.

2. Action part: front and rear wheels, including front and rear axle components, spokes, rims (RIMS), tires, etc.

3. Safety device: including brake (brake), lamp, bell, reflector, etc.

Some accessories can be added as needed, such as bracket, clothes hanger, safety fork, fender, air cylinder, etc. In addition, sports cars, racing cars and mountain bikes equipped with variable speed mechanism are also equipped with variable speed controller and front and rear derailleurs.

4. Composition of hand foot dual power bicycle: an alloy box is added to the frame of the traditional bicycle. The box contains various transmission parts. Through the interaction of forces, the hand foot dual power and simple push-pull handlebar action are realized, so that the handlebar can make the car move forward, which is not only labor-saving, but also fitness.

Frame components

1. The frame components are the basic structure of the bicycle, as well as the skeleton and main body of the bicycle. Other components are also directly or indirectly installed on the frame.

There are many structural forms of frame components, but they can be divided into two categories: Men's frame and women's frame.

Because the bicycle is driven by the driving force and cycling skills of the human body, the frame has become an important structure to bear the impact load generated by the bicycle and whether it can carry the human body comfortably and safely. The manufacturing accuracy of the frame components will directly affect the safety, stability and lightness of the ride. Generally, the spokes are of equal diameter. In order to reduce gravity, they are also made into variable diameter spokes with large ends and small middle, and they are made into flat streamline in order to reduce air resistance.

2. Outer tire: divided into soft tire and hard tire. The soft tire has a wide section, can completely wrap the inner tube, has a large landing area, and is suitable for driving on a variety of roads. The hard tire has light weight and small landing area. It is suitable for driving on flat roads. It has the advantages of low resistance and light driving.

The pattern on the outer tire is to increase the friction with the ground. The tire width of mountain bike is very wide and the pattern is deep. It is also suitable for cross-country mountain.

3. Pedal parts: the pedal parts are assembled on the left and right cranks of the central shaft parts. It is a device that converts the flat power into rotational power. When the bicycle is riding, the pedal force is first transmitted to the pedal parts, and then the pedal shaft rotates the crank, tooth disc, central shaft, chain flywheel to rotate the rear wheel, so as to make the bicycle move forward. Therefore, whether the structure and specification of pedal components are appropriate will directly affect whether the cyclist's foot placement position is appropriate and whether the bicycle drive can proceed smoothly.

Pedal

Pedal: it can be divided into integral pedal and combined pedal. No matter what style of pedal, it must have a pedal surface, be safe and reliable, have certain anti-skid performance, and can be made of rubber, plastic or metal materials. The foot pedal must rotate flexibly.

4. Front fork part: the front fork part is in the front part of the bicycle structure. Its upper end is connected with the handlebar part, the frame part is matched with the front pipe, and the lower end is matched with the front axle part to form the guiding system of the bicycle.

Turning the motor car handle and front fork can change the direction of the front wheel and play the guiding role of the bicycle. In addition, it can also control the driving of bicycle.

The stress of the front fork belongs to the nature of cantilever beam, so the front fork must have sufficient strength and other properties.

chain

5. Chain: the chain, also known as car chain and roller chain, is installed on the coupling wheel and flywheel. Its function is to transfer the pedal force from the crank and sprocket to the flywheel and rear wheel to drive the bicycle forward.

Sprocket: made of high-strength steel to ensure that it reaches the required tension.

6. Flywheel: the flywheel is screwed and fixed on the right end of the rear axle with internal thread, keeps the same plane with the sprocket, and is connected with the sprocket through the chain to form the driving system of the bicycle. Structurally, it can be divided into single-stage flywheel and multi-stage flywheel.

The single-stage flywheel, also known as the single chain wheel flywheel, is mainly composed of an outer sleeve, a flat stop and a core, a kilogram, a kilogram spring, a washer, a wire stop, a few steel balls and other parts. The working principle of the single-stage flywheel: when the pedal is stepped forward, the chain drives the flywheel to rotate forward. At this time, the internal teeth of the flywheel are contained in the kilogram. The rotating force of the flywheel is transmitted to the core through the kilogram. The core drives the rear axle and rear wheel to rotate, and the bicycle moves forward.

When the pedal is stopped, the chain and the jacket do not rotate, but the rear wheel still drives the core and the jack to rotate forward under the action of inertia. When the pedal is pressed in the opposite direction, the jacket rotates in the opposite direction, which will accelerate the sliding of the jack and make the "dada" sound faster. Multistage flywheel is an important part of bicycle transmission.

The multi-stage flywheel is based on the single-stage flywheel. Several flywheel pieces are added and combined with the sprocket on the central shaft to form various transmission ratios, thus changing the speed of the bicycle.