Robert Lurvy, a famous American anthropologist, once asserted that all people who use unicycles learn from Babylon directly or indirectly. American Indians know that tugboats, spinning wheels and hoop rolling are used to roll logs, but they have never thought about the significance of driving on wheels.
Lu Wei's view on the origin of the wheel is also the view of most archaeologists. But new archaeological discoveries often subvert old theories. The rut under the stone tomb of Flintbeck in Germany was left 6800 years ago (4800-4700 BC).
The car-shaped tank discovered in Bronocice, Poland, was located before 4725 BC, but the seven carbon-14 dating of this stratum tends to the conclusion of 46 BC10-4440 BC.
The earliest evidence of wheeled vehicles in the Near East was discovered by American archaeologist Bardia at the site of uruk in Syria. A model with wheels and a "truck" mural were unearthed there. These things were left by our ancestors 6400-6500 years ago.
Therefore, wheeled vehicles are likely to appear in Europe, then spread to the Near East, or be re-invented by orientals.
Extended data
At present, most wheels used are steel wheels. Due to the casting process, the greater the rim mass of a rigid wheel, the thicker the spokes needed and the greater the wheel mass. The wheel mass is unsprung weight, and the increase of its mass has great influence on the vertical force of wheel and rail.
In order to improve the hardness of the rim and prolong its service life, the wheel tread is quenched during production. Due to the characteristics of quenching process, the quenching depth is limited. The thicker the rim, the lower the internal hardness and the worse the wear resistance. Although the service life of wheels is prolonged with the increase of rim thickness, the proportion of extension is getting smaller and smaller.
Considering the service life of the wheel, the thicker the rim, the better. However, considering the wheel weight and the diameter difference between the old and new wheels, the rim thickness should be as small as possible. Rim thickness has its own advantages and disadvantages, which should be comprehensively determined according to the specific use conditions of freight cars and the above-mentioned various influencing factors.
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