Tire class: the difference between oblique and radial tires!

- Jul 22, 2019-

What is called oblique twins, what is called radial twins, this is the question that friends often ask.



There are many types of tires.

Both oblique and radial tires belong to pneumatic tires, which are named respectively according to the different lamination forms of tire body fabric.


The pneumatic tyre is mainly composed of rubber parts and curtain layer.

Don't see the appearance of tires "all over" is rubber, but rubber in the tire body only has a combination of the tire body parts, sealing, wear-resisting, barbed and part of the buffer effect, not really "output", the real "output" is hidden in the rubber inside the curtain.


Curtain fabric, also known as curtain fabric or cord, cord.

Although it is called cloth, the curtain does not look like cloth at all.

This is a kind of fabric with coarse warp and dense weft and thin weft.

When spread out, the curtain is something like a "bamboo curtain" -- you can think of its warp as strips of bamboo and its weft as threads of cotton that weave the strips together.

It is because of this resemblance that it got the name of "curtain".

Common curtain cloth has cotton curtain cloth, nylon curtain cloth, rayon curtain cloth, polyester curtain cloth, steel wire curtain cloth and so on.

Curtain fabric is used as skeleton material in tire, which is the main stress component of tire.

That is to say, the tire by the inflation pressure and vehicle load, prevent the tube inflated after the expansion, protect the tube from mechanical damage, transfer traction and braking force and other "output" work, almost all by the curtain hidden in the tire rubber "unknown hero" to assume.

In this regard, the emergence of rubber is not much help.


Because the tire must rely on "the curtain cloth" to the effort, the strength of the curtain cloth meridian defecates decides the tire performance, and then affects the tire manufacture technology development.


Characteristics of an oblique tire


Early on, people used cotton fiber to weave curtain cloth.

Due to the low strength of cotton fiber curtain, in order to reduce the stress of the cord, people on the one hand increase the number of layers of the curtain, on the other hand make the cord layer in the matrix according to a certain Angle of cross arrangement.

Due to the two adjacent layers of the curtain fabric meridian tilt cross each other, so people put this kind of cord lamination form of tires known as "oblique tire."


The Angle of perpendicular intersection between the cord line and the center line of the tire crown is called "tire crown Angle".

The crown Angle of "oblique twins" is generally in the range of "48 ~ 54°".


In order to identify the maximum allowable load strength that a tire can bear under specified operating conditions, the concept of hierarchy was introduced in early tires.

It originates from the maximum allowable load that can be borne by cotton curtain cloth layer. If this tire is made of four layers of curtain cloth, it is called four layers. It indicates that this tire can bear the load within the range of four layers.


With the emergence of some stronger cord such as synthetic fiber cord and its widespread use in tires, the number of layers of tires using new fiber cord is higher than the actual number of layers.

That is to say, the number of layers can no longer reflect the actual number of layers of tire curtain.

In general, the actual number of levels is lower than the number of levels.

Such as the 10 level of tires, its curtain layer may only 6 or 8.


In order to make the cord in the tire evenly stressed, the number of layers of the diagonal tire is even.

Therefore, the level of bias is even.

The levels of motor vehicle tires are generally between 4 and 20, and some are higher than 20.

Oblique tire is a kind of tire which is developed and fixed under the limitation of insufficient cord strength.

The advantages of this kind of tires are solid tire body, small load deformation, tire side is not easy to damage, steering and braking performance is good;

In addition, long production history, good technology, high production efficiency, low processing costs.


Because the inner structure of this kind of tire directly affects the performance of the tire, so the bias tire also has inherent deficiencies, which is: raw material consumption, wear in the process of use, poor grasping performance, rolling resistance, high temperature in the tire body.

This kind of tyre can not only fuel the car, but also limit the speed and mileage.

Developed region in the early 1960 s abroad tyre production still dominate, starting from the mid sixties especially to 60 s plummeted, its proportion is now in the developed countries and regions have fallen to below 20%, and the motor vehicle with bias tire production is still accounts for over 60% of the same specifications tyres production.


Characteristics of radial tires


With the progress of society, new and higher strength cord fiber materials have been developed and put into use, which brings about the innovation of tire body structure.

Radial tire is under this kind of background, became the replacement product of oblique tire.


Radial tire, referred to as radial tire.

This is also a kind of pneumatic tyre made of cord cord as the frame material by laminating process.


On a graph on the surface of a globe, it is often marked with a line connecting the north and south poles. This is the meridian.

If the radial tire is exposed through the tire side cord, and the endpoint is extended to the tire axis position, then look at the tire cord arrangement, much like the meridian arrangement on a globe.

Hence the name meridian tire.

Also because the meridian is the earth's meridian, early years also known as the meridian fetus "meridian fetus."


The English name of radial tire is "radial tire", which means "radial tire".

It's also very graphic.

If you take the inner ring of the two circles formed by the projection of the tire as the sun, then the tire side cord is very much like a radiant radiation.

It's called the radial tire.


As the English name of radial tire is "radial tire", "R" is the code name of radial tire in the international identification.

For example, a tire is marked "900R20", which means it is a radial tire.

If the mark is "900 -- 20", it means it is an oblique.


Meridian tire cord in the body from the toe of the tire to the other side of the meridian tire cord, is an open circle.

The tire crown Angle is in the range of 0 ~ 15°.

These cord constitute the tire skeleton layer, professionally called "curtain layer".

Because cord relies entirely on warp to produce strong force, weft plays the role that connects adjacent warp only, pull with the hand gently can disconnect.

If only relying on the weft cord and rubber produced by the strength, when filled with gas or driven, braking, radial tires easily from the two meridian break.

In order to eradicate this "weak link", along the circumference of the tire, between the tire crown rubber and the cord layer, to the cord layer hoop composed of several layers of cord "belt", known as "belt belt layer".

The banding layer is usually made of high strength and little tensile deformation of fiber cord (such as glass fiber, polyamide fiber and other high strength materials) or steel cord.


In general, the material of the curtain layer is steel wire, but the material of the belt bundle layer may be steel wire, or nylon and other fiber materials.

Where the cord layer and belt bundle layer are steel cord fabric, called the full steel radial tire, referred to as "full steel tire";

If the curtain fabric layer for steel cord fabric, with a bundle layer for nylon a kind of fiber material curtain fabric, it is called the semi-steel tire.

Usually, the passenger motor vehicle installation is "half steel tire";

Heavy-duty vehicles are fitted either with "all-steel tyres" or with slant tyres.


The bias tire does not have the steel cord, certainly also does not have the entire steel or the half steel bias tire to say.

When you say "all steel" or "half steel", it definitely means radial.

Due to the low strength of natural fiber cord such as cotton fiber, it is not suitable to manufacture radial tires, so today there is no use of natural fiber cord such as cotton cord to manufacture radial tires.

This is partly the difference in the material of the skeleton.


If you think of rubber as cement, the cord in the tire is like steel.

This makes the tire with rubber as the muscle and cord as the skeleton has the strength to withstand all kinds of forces.


As early as 1993, British men Gray and Sloper had invented the radial tire, but the technology was not mature.

It was not until the Michelin company in France studied to fix the shape of the tire body from the tire body with multi-layer small-angle steel band layer and put into production in 1948 that the radial tire officially entered the process of replacing the oblique tire.


Comparison of the structure and performance between radial tire and ordinary oblique tire


(1) structural characteristics


(1) curtain cloth layer of cord arrangement direction and tire meridian section included Angle is 0 degrees

(that is, the included Angle with the tread center line is 90 degrees).

This arrangement of cord is very similar to the meridian of a ball (that is, the meridian), so called meridian tire.

This arrangement of the cord, so that the intensity of the cord to get full play and use, so that the number of radial tire cord layer is generally less than the ordinary bias tire 40% to 50%.

Generally only 1-4 layers, steel radial tires generally only a layer of curtain layer,


(2) cord between the only rubber to maintain circular contact.

Travels to withstand large tangential force, generated by the radial tire adopts multi-layer, large Angle (an Angle and meridional section of 70-75 degrees), high strength, not easy to stretch like a buffer layer with beam layer (also known as hard or buffer layer. Banding layer), to strengthen the tire crown, like a rigid band, tight on wheel (3) the section of meridian tyre is wide, the cross section of the aspect ratio (H/B) for running around 0.7.


(2) performance characteristics


Compared with ordinary bias tire, it has large elasticity and good wear resistance (the life span can be increased by 30% to 50%).

Small rolling resistance (can reduce the car's fuel consumption of about 8%), adhesion performance (in the muddy soft road is not easy to skid), carrying capacity, not easy to be punctured, good buffer performance, can better improve the running of the sprinkler.

Its disadvantages are: tire side easy to crack, due to the surface deformation, resulting in sprinkler lateral stability is poor, manufacturing technology requirements, high cost.


Use in best install with radial tire, or use alone on the rear axle, but cannot use radial tire alone on the front axle, rear axle USES common bias tire, also cannot mix with common bias tire in a car axle, use in should press standard air pressure to inflate strictly, do not allow deficient air to use, turn when the speed should be low, brake do not want too fierce etc.


Of course, the radial tire is not perfect, it also has some disadvantages that are not easy to overcome.

For example, the lateral stability is poor, the tire side is easy to crack, the manufacturing process is complex, the production efficiency is low, the cost is high.

Due to the difficulty and high cost of manufacturing, radial tyres of the same specification are far more expensive than bias tyres.


The structural characteristics of radial tire give this kind of tire a lot of excellent performance and produce some remarkable technical and economic effects.


The radial wheel has the following advantages over the oblique tire:


1.

Save raw materials.

Because the tire cord is arranged according to the meridian direction, and the tire deformation direction is the same, the cord strength can be used more effectively, thus the number of cord layer and the corresponding amount of rubber can be reduced.

Compared with oblique tire, the number of curtain layer can be reduced by 40 ~ 50%, the amount of rubber can be reduced by about 20%, and the tire weight can be reduced by 5 ~ 8%.


2.

Good vibration damping performance.

Because the tire body is thin and soft, the shock and shock can be significantly reduced, making the ride smooth and comfortable.

And can reduce the wear and tear caused by violent vibration, reduce maintenance costs.


3.

Good wear resistance.

The circumferential banding layer strengthens the tire crown and makes the circumferential extension impossible, which greatly reduces the sliding friction of the tread along the road surface during the rolling process, and significantly improves the wear resistance and mechanical damage resistance of the tread.

The wear resistance can be increased by 30 ~ 70% compared with the bias tire.


4.

Hold on tight.

The tread body is soft, with large subsidence, large contact area between tread and pavement, and even contact pressure distribution.

In addition, the tire crown is rigid and the tread slip is small in circumferential direction. Therefore, the tread and pavement have good grasping performance, and the grasping force can be increased by 10 ~ 50% compared with the oblique tire.

Good traction and off-road performance, safe driving.

When driving on muddy road and snow and ice road, skidding phenomenon is less, good passability;

When driving in mountainous areas, it has good climbing performance.


5.

Operation temperature rise is low.

The radial tire cord is arranged in such a way that the internal friction caused by shear movement between the cross-arranged layers of the oblique tire is eliminated, so the heat generation is low and the energy consumption is low.

In addition, because the number of tire body curtain layer is less, the tire side is thinner, which is also convenient for internal heat emission.

Therefore, this kind of tire is lower than the oblique tire in the running heat accumulation in the tire, in general, can be 30 ~ 70% lower.

For example, the oblique tire runs at the speed of 69 km/h, and the internal accumulated temperature can reach 120℃.

The radial tire runs at 110 km/h with an internal accumulated temperature of only 104℃.

Because of the low running temperature, the running speed can be increased.

In general, it can increase by 20 to 30 percent.

With the decrease of energy consumption, oil consumption decreases correspondingly.

The fuel consumption can be reduced by 5 ~ 13% compared with the oblique tire.

This not only saves fuel costs, but also helps reduce air pollution.


6.

Long service life.

The superior performance is comprehensively reflected in the service life. Compared with ordinary structural tires, radial tires can increase the mileage by 50 ~ 100%. The average road surface can reach more than 100,000 kilometers, the good road surface can reach 140,000 kilometers, and the bad road surface can reach about 70,000 kilometers.


If the bias tire is the representative product of the first stage in the history of tire production technology, then the radial tire is undoubtedly the representative product of the second stage in the history of tire production technology.

In the future, it is likely that the radial tire will be replaced by a representative product of the third stage in the history of tire production.

That's for sure.

Because the world is improving every day, so is the tire manufacturing industry!