"Why is the wheel round?" This problem has attracted the attention and thinking of students of different ages. The following is a detailed explanation of why the wheel is round, for your reference.
Detailed explanation of why the wheel is round
There are two main reasons, labor saving and peace and stability
The use of wheels is a major progress in the history of human civilization.
The wheel can save labor, because the circle can reduce friction resistance and speed up
Improving efficiency is the major advantage of wheels:
Rolling is used to replace the physical weight of human and animal forces.
When an object is in motion, the center of gravity remains unchanged, and the fluctuation of the center of gravity will not consume power (human or animal power).
A circle has such a characteristic: the distance from the center of the circle to any point on the circumference is equal. This equal distance is called the radius. That is to say, "in the same circle, all radii are equal." Therefore, people make the wheel into a circle and make the axle pass through the center of the circle. When the wheel rolls on the ground, the distance between the axle and the ground is always as long as the radius of the wheel. Only in this way can the driving be smooth
History of automobile tires
In 1895, with the emergence of automobiles, pneumatic tires were widely developed. The first batch of automobile tire samples appeared in France in 1895. This is a single tube tire made of plain canvas, which has tread rubber but no pattern.
In 1892, British Burley mill invented cord fabric and used it in production in 1910. This achievement not only improved the quality of tires and expanded the variety of tires, but also made the outer tire possible to be molded. With the improvement of tire quality requirements, the quality of cord fabric has also been improved. Cotton cord fabric was replaced by rayon. At the end of the 1950s, rayon was replaced by nylon and polyester cord with better strength and higher heat resistance. Moreover, steel cord has strong competitiveness with the development of radial tire.
In 1904, Matt created the carbon black reinforcing rubber, which was used to strengthen the tread rubber on a large scale after the tire adopted the cord fabric, because before that, the canvas was damaged faster than the tread in the use of the tire, and the amount of carbon black in the rubber increased rapidly. In the 1930s, only about 20 parts of carbon black were used in every 100 parts of raw rubber. At this time, carbon black was mainly used on the tread, and more than 50 parts of the carcass were not used. Before adding carbon black to the tread, the tire was polished after only driving 6000km. After adding carbon black, the mileage of the tire was significantly improved soon. A set of truck tires can travel about 100000 km, and even 200000 km on good roads.
From 1913 to 1926, the invention of cord and carbon black tire technology laid the foundation for the development of tire industry. The standardization of tire outer edge, the gradual improvement of manufacturing technology, the production speed is higher than before, and the output of tire is increasing day by day.
With the development of automobile industry, the tire technology has been continuously improved and improved. For example, from the early 1920s to the mid 1930s, the car tire changed from low-pressure tire to ultra-low-pressure tire; Since the 1940s, tires have gradually transitioned to wide rims; The emergence of tubeless tires in the late 1940s; In the late 1950s, low profile tires came out and so on. The appearance of many new technologies is nothing more than the radial structure tire pioneered by French Michelin company in 1946. This kind of tire is known as the revolution of tire industry due to the significant improvement of service life and performance, especially fuel saving in driving. Here is a brief introduction to the main tire characteristics of today's development.
Early cars used wooden or iron wheels, the suspension structure of the car was not perfect, and the driving conditions on the road were not good. Although the driving speed of the car was not high, it was still bumpy. A naval Colonel's feelings about taking an early car were as follows: "it was my first attempt to use a vehicle without a horse. In 1886, I took an iron wheeled car driving on a rugged granite road. The violent turbulence of the car reminded me of the instructions on the medicine bottle - shake well before taking it".
The first hollow wheel was invented by the Englishman Robert Thomson in 1845. He proposed filling the elastic bag with compressed air to alleviate the vibration and impact during movement. Although the tires were made of leather and coated canvas at that time, this kind of tire has shown the advantage of low rolling resistance. According to this principle, John Dunlop made the rubber hollow tire in 1888, and then Thomas made the rubber hollow tire with valve switch. Unfortunately, because there is no canvas in the inner layer, it can not maintain a certain section shape and width.
The emergence of rubber tires is a prerequisite for the further development of automobiles. When it comes to rubber, people naturally think of Charles Goodyear, the father of rubber. In 1834, inspired by coke steelmaking, he began the experiment of soft rubber hardening. After numerous failures, by chance, it was found that vulcanized rubber was not sticky and elastic when heated, so hardened rubber was born, and the rubber tire manufacturing industry came into being. In 1895, with the emergence of automobiles, pneumatic tires were widely developed. The first batch of automobile tire samples appeared in France in 1895. This is a single tube tire made of plain canvas, although it has tread rubber but no pattern.
It was not until 1908-1912 that the tire changed significantly, that is, there were patterns on the tread rubber to improve the service performance, which opened up the history of the tire tread pattern, increased the section width of the tire, and allowed the use of lower internal pressure to ensure better cushioning performance.