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What is the Differential for 4×4 Off-Road Vehicles? What is the Great Importance of Differential?

Off-road and differential : Differential is one of the most important elements of offroad. The answer to why a vehicle we think is a 4×4 is actually a 4×1 is hidden here. Everyone who goes to the field should have this basic knowledge and interpret what he can or cannot do with the land car under what conditions. None of the sentences are quotes. Some of the information is original and only reasoning that belongs to this article. So it’s not anywhere else. Our aim is to explain the differential with a philosophical approach. The difference between differentials with different mechanics or their own details is not very important to us. The important thing is the purpose of use and the service they provide.

What is a differential? How does the differential work?

What is a differential and why is a differential needed? It is the general name of the mechanism that provides power transfer to the tires by tolerating the lap difference between the wheels during differential driving . The differential does not make the wheels turn at different or the same speed, it just allows it. When a vehicle is cornering, all 4 wheels go on different tracks. Because each track has a different radius, all wheels rotate at different linear speeds. We can see this in the first picture. If there is no internal mechanism to tolerate this situation, the wheels will try to tolerate the lap difference with short skids. These skids force the vehicle’s drivetrain unnecessarily and cause the tires to wear more than normal. If the driveline is not strong enough, it can also cause axle cuts or similar breaks.

What is the main working principle of the differential?

How does the differential work? Before reading my answer to the question, I will recommend you to watch these two videos.

As explained in the videos and understood from the second picture, the joint called the U-joint (universal joint) at the end of the shaft connects the shaft to the bevel shaft and drives it. As a result, in the differential the chainring starts to rotate . In the differential housing, 4 pieces of axle gears, 2 each 2 in opposite directions, and known as idler gear-cross gear-spider gears etc. There are gears . In the differential, the housing is fixedly attached to the mirror. When driven from the shaft, the bevel rotates, the beveled chuck rotates, the chamfer rotates the housing, the idler gears actuate the axle gears by pushing, not by turning . Pay attention here . By pushing, not turning. This activates both axles. In other words, the rotational movement transferred from the gearbox to the differential and from there to the axles is not a uniform gear movement as it is known. If for some reason the axles feel the need to make different turns, then the idler gears respond to this need for different turns by not only pushing but also turning. This is the main operating principle of the most well-known differential type. It is not important to us what the details of the differential types with different mechanics are. The important thing is that they all provide the same service. Here’s the answer to why we couldn’t keep moving forward when the vehicle fell diagonally. Motor power is like electric current, where the resistance is less, it escapes to that side. So if a wheel loses traction, it absorbs all the power of the engine and continues to idle. In the meantime, the vehicle struggles and stalls because there is no power going to the wheel that is on the ground, which can provide traction. Although this situation usually occurs in the position we call diagonal, there may also be situations where two wheels on the same side have simultaneous gripping problems.

What are the differential types?

When you do research on the subject on the internet, you will see the following differential types in both domestic and foreign sources.

1-) Open Differential Type (Open Differential)

2-) Locked Differential

3-) Viscous Limited Slip Differential Type (Viscous Limited Slip Differential)

4-) Mechanical or Electrically Controlled Limited Slip Differential Type (Mechanical Clutch-Type LSD, also eLSD)

5-) Torsen & Helical Differential

6-) Torque Vectoring Differential

BLA bla. There are conceptual contradictions in these classifications. Therefore, I will touch on the subject with a different approach without depending on these classifications. As I said, we will have a philosophical approach in this article. Above I explained what a differential is and what we need in off road vehicles. That’s why we’re just going to call the differential differential throughout this article, taking into account the basic function of the off-road differential , regardless of the differences in its working principle.

What is a locked differential?

A locked differential is a differential whose turn difference tolerance capability between the right and left axle is reduced or completely eliminated , depending on the method used to lock it. In fact, the differential types given above are somewhat of a variation on these key method differences. That’s why I’m going to call the lock a lock. After all , when you say locked differential, you understand, as I said above, “differential with reduced or completely eliminated lap difference tolerance between right and left axles” . The master thesis is derived from the lock types and working principles. That’s why I won’t go into too much detail and I will examine it in 4 main categories. Behaviors in these categories can be achieved with different methods and mechanical structures. This detail is not very important to us. The service we receive and the result are important to us.

Differential Systems Providing Full Locking in the Vehicle

These differential systems provide a complete locking in the vehicle mechanically and transfer half of the power from the pinion gear to the right axle and half to the left axle. The lock that interests us more is the mechanical lock . What is a mechanical lock? The basic principle of the mechanical lock in the vehicle is to prevent the axle gears from turning in different turns . This is easily achieved by preventing free rotation of the idler gears. In other words, whatever your left axis turns, your right axis will turn the same. That’s why we never activate such locks on non-slippery surfaces in order not to force the vehicle mechanics unnecessarily in corners that need a lap difference.

Differential Systems Providing Partial Locking in the Vehicle i

The most widely known is the LSD differential. (Limited Slip Differential). These 4×4 differential systems serve similarly to full locking differentials, but they can never transmit power equally to the right and left axles. Or, in the differential systems of some vehicles, the wheel must be on the ground in order for the locking mechanism to function. Therefore, they are more inefficient than fully locked differential systems . In fact, due to the mechanical wear experienced over time, its presence or absence is incomprehensible in old cars.

Differential Systems That Can Transfer Different Power To Right And Left Axles

VLSD (Viscous Limited Slip Differential) , e-LSD is one of this group of differentials. These systems have different power transfer capabilities between the right and left axles depending on the need. In some systems, the system does not activate until the difference in lap between the axles occurs. There are heating problems in conditions where they are switched on and off very often. In addition, mechanisms have a lifespan, too frequent switching on and off shortens this life.

Differential Systems utilizing the Vehicle Brake Mechanism

What is EDL? (electronic diffrential lock) EDL-based traction support systems. We can include all electronic traction control systems in this group. Each brand gives a different name to EDL-based systems, but the basic working principle is this. Off-road vehicles with EDL roof traction support system have sensors that count laps on the axle. These are ABS sensors. Although their main task is to serve in the ABS braking system, it is the basic data provider of many systems such as EDL, ASR, ESP etc. The vehicle detects the lap difference on the right and left axles through ABS sensors. If the difference is outside the prescribed tolerances, it automatically brakes the wheel with the excess lap. Therefore, the engine power does not flow senselessly to the idle wheel, but to the traction wheel, and the vehicle can continue walking.. Although this system seems successful , it is not efficient under heavy usage conditions . It’s like pressing the accelerator while pressing the brake at the same time. It may cause problems such as abrasion, heating, scratching etc. on discs and pads. Let alone the new generation, the land is located in almost all of the passenger cars with different names.

If we look at the lock situation collectively; If you do not have a middle lock and differential locks in your off-road vehicle: Your vehicle is 4×1 . If one wheel of your 4×4 off road vehicle loses traction, that wheel will absorb all the power of the engine and you will not be able to drive your vehicle .

If you have a Middle Lock but no differential locks : Your vehicle is 4×2. If the front two wheels or the rear two wheels are holding the road, you can continue driving. If one of the front and rear wheels (no matter left or right) loses traction at the same time, you will not be able to continue driving. If there is a middle lock and a rear lock: Your vehicle is 4×3. As long as the two rear wheels and a front wheel do not lose traction at the same time, you can continue your ride. If the rear two wheels lose traction, all power flows to the front shaft. If a front wheel also loses traction, this time all power goes to the one wheel that loses traction at the front. This is a difficult situation to deal with. If there is a middle lock and front-rear lock: Your vehicle is a 4×4. Unless all four wheels lose traction, you’re not stuck on the road.

Off road differential options depending on your preference that you need to apply in order to modify the 4×4 off road vehicle, which has the ability to go anywhere in difficult terrain conditions.

Conclusion and Suggestions: There are many criteria for the selection of the off-road car. In my opinion, the most decisive of these criteria is personal taste. Therefore, there is no arithmetic such as 2*2=4 for this job. My advice, do not buy a vehicle that does not have a middle lock. If possible, get at least a vehicle that originally had a rear lock, or one that could be rear-locked without much expense. If you don’t have one, put the rear lock at the beginning of the modifications you intend to make to the vehicle you bought. Regards, Love.

02.03.2020 Süleyman Atılgan Contact: Facebook & Instagram

You can view other articles professionally prepared by Süleyman Atılgan, which include off-road basic techniques and off-road driving advice, below.

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