There are two types of anti-skid chains: iron chain and plastic chain. Among them, the cost of iron anti-skid chain is the lowest, but the applicable scene and anti-skid ability are also the lowest. Why do you say so?
Because the calculation formula of the dynamic friction coefficient will say this: dynamic friction coefficient = pressure ÷ sliding friction force
The principle of friction heating is almost a well-known physical phenomenon. The degree of friction between the vehicle and the road surface is related to the vertical pressure between the wheel and the snow or ice surface, as well as the pressure generated by the crown width. Take Snowboard as an example, the friction coefficient of metal material will be slightly lower than that of wooden snowboard, because under heavy pressure, the contact position between the friction surface and the ice surface will produce a slightly higher temperature, which will cause the melting of the ice surface, forming a layer of water with a thickness of about 1mm. The slippery snow and ice surface is realized by these water. The ability of metal to absorb heat will be faster than that of wood materials, so the water produced by metal anti-skid chains will be less, and the friction will naturally be higher than that of wood anti-skid chains, that is to say, the anti-skid ability of metal anti-skid chains on snow or ice will be stronger.
However, the fact is that the iron anti-skid chain is only suitable for the snow surface rather than the ice surface, because even if there is no dissolved water, the friction coefficient of the ice surface is only about 0.02. And the contact surface between the iron chain and the ice surface is very small, and the friction is still insufficient to prevent sideslip; Secondly, due to too small lifting, the vertical pressure is too large, and high temperature will still be generated in the process of high-pressure friction, resulting in dissolved water. The contact surface of the snow chain is not as large as the snowboard. As for the anti-skid of iron chain on the snow surface, its principle does not simply rely on friction; Through the heavy pressure of the vehicle and the bulge of the anti-skid chain, the dents are pressed out on the hard snow, and the wheels are pulled out of trouble by pinning these dents in the process of rotation, which is the same as the principle of mud mud tires pressing out grooves on soft land.
Key: under extremely low ambient temperature, the hardness of the ice surface will be very high, and the lower the temperature, the higher the hardness. The Mohs hardness standard is roughly as follows:
You should know that the Mohs hardness of general steel is only 4~5. In the face of ice with extremely high hardness, iron chains cannot crush the ice. As a result, iron anti-skid chains slide rapidly on the ice because of water.
For most vehicles commuting on urban roads, the main driving surface of this kind of vehicles is paved roads; After snow, the road will freeze with the change of temperature difference or melting snow with salt, so the car will mainly face the ice surface rather than the relatively soft snow surface. If you want to commute on the ice, you need to get the ability to compress the ice. The only way is to use the snow chains made of thermoplastic rubber (TPE) commonly known as “ox tendon”. The chain surface of this kind of anti-skid chain will be distributed with some sharp conical nails, and the pressure will increase when the stress surface becomes smaller, and the ice surface will be crushed by these nails to form a grip; In winter tires, there is a kind of anti slip nail tire, which has the same function as this kind of anti slip chain, but the cost is much higher. The durability of TPE anti-skid nail chain is not very strong, but it can always be satisfied by occasional use. However, in the process of use, attention should be paid to the installation of front and rear wheels at the same time. For example, the fact that the friction of the rear wheels is low can not be changed if only the front wheels are installed in the front drive, and the natural acceleration of the speed after the use of snow chains will lead to a higher probability of side slip when the vehicle turns. The rear wheel of the rear drive gets a lot of friction through the anti-skid chain, and the multiple greater than the front wheel will increase too many times. At this time, when the vehicle turns, the rear wheel will directly push the front wheel to go straight, and the vehicle cannot turn normally.
Conclusion: the anti slip nail chain is suitable for most automobile users. It must be installed on all four wheels, otherwise it’s better not to use it.