The Niva car became the first Soviet off-road vehicle, the device of which used an all-wheel drive transmission. A characteristic feature of the car is the center differential lock mechanism. There is an opinion among motorists that this mechanism serves to connect front axle. However, the Niva front-wheel drive is always connected. You can figure out which drive Niva has after studying the design of this unit.
Niva drive device
The chassis of the car is made on the principle of permanent all-wheel drive - from power unit transmitted to all 4 wheels. This scheme improves the performance of the car when driving in off-road conditions, while reducing the load on the transmission parts.
The Chevrolet Niva drive consists of the following components:
- Gearbox.
- Transfer case.
- A pair of drive and cardan shafts.
- Gearboxes front and rear axles.
The transfer box is designed to distribute torque between the drive axles vehicle. The car is equipped with a two-speed "razdatka", which provides:
- stable running of the machine when driving at low speed in the mode of increased engine speed;
- distribution of power between the drive axles, depending on the grip with the road surface.
The differential is one of the most important elements of the transmission. Its main purpose is to distribute the traction force, and, if necessary, ensure the rotation of two consumers with different angular speeds. In drive transmission Chevrolet Niva There are three differentials:
- One for each axle (cross-axle) - allow the wheels of one axle to rotate at different speeds.
- The third (inter-axle action) - transmits power from the power unit to both vehicle axles. It also allows the shafts to operate at different angular speeds, depending on the operating conditions, which greatly improves controllability.
A pair of cardan shafts (joint or cross design) provide a connection between the transfer case and the drive axle gearboxes. Both shafts of the car have the same device - they are interchangeable.
front and rear axle We transfer the force from the transfer case to the drive wheels through external and internal angular velocity joints.
The principle of operation of all-wheel drive on a Chevrolet Niva
In normal mode, Chevrolet Niva works in overdrive with an unlocked differential. The torque is transmitted from the power unit, through the gearbox and intermediate shaft, to the two-stage gearbox of the transfer case. In the case of "handouts" is installed center differential. It links the front and rear axles, allowing them to rotate at different speeds, depending on road conditions and directions of movement.
How all-wheel drive works on Niva with a locked differential
With all-wheel drive engaged, both cardan shaft secured with a locking collar. This contributes to the uniform transmission of traction to both axles of the vehicle. Due to this, the vehicle's cross-country ability increases, but controllability worsens.
Tip: It is not recommended to use the lock mode on roads with good grip, as this will lead to accelerated tire wear, increase the load on transmission parts and components, and increase fuel consumption.
How to enable all-wheel drive
Since the drive on the Niva is constantly full, it is questionable how to turn on four-wheel drive on the Chevrolet Niva, it is understood how to turn on the center differential lock.
Blocking should be used in the following cases:
- when driving on difficult terrain where there is a risk of wheel slip;
- when there is a lack of engine thrust;
- when driving on a road covered with snow or ice.
Important: Locking is useless when the car is hanging diagonally, when slipping begins on one wheel on different axles. It's connected with design feature transmission. In this case, you need to act according to the situation - dig or pour under the hung wheels.
The main component of the bridge locking mechanism is the transfer case. Control transfer case operated by a single six-position lever. Longitudinal travel provides high and low gears. Transverse - is responsible for blocking the center differential. When the lever is in lock mode, a yellow icon lights up on the instrument panel. There are no synchronizers in the transfer case design, therefore, when you try to turn on the speed range or lock, the gears get tooth on tooth. To switch, you just need to move the car forward or backward and then everything will switch.
VAZ 21213 "Niva" is one of the most successful and significant developments for the Volga Automobile Plant. We can say that the Niva is the most significant model in the entire history of the domestic automotive industry. Initially this machine characterized as a passenger car with all-wheel drive 4x4. What secrets does this model hide, what does it have under the hood and how long has it existed? All this and more - further in our article.
Production history
Serial production of the VAZ Niva 21213 began in 1977. The most eminent design engineers of the USSR were involved in the development of this SUV. Probably, it was the cohesion of all the actions of the design bureau employees that made it possible to create a car characterized by high cross-country ability, light weight and unpretentious maintenance.
VAZ "Niva" 21213 is the first car in the history of the domestic automotive industry, which was created specifically for off-road driving, traveling to the most inaccessible places, as well as for fishing and hunting trips. All this was facilitated not only by all-wheel drive and a powerful gasoline engine for those times, but also by the practical layout of the body - a folding backseat allowed to place various household goods weighing up to several hundred kilograms inside the Niva.
Domestic "Range Rover"?
What unites the domestic with the British "Rover"? At first glance, absolutely nothing. However, one has only to look at the technical part, and everything will become clear. The fact is that the Niva used a non-switchable drive on all four wheels with a transfer case and an interaxle locking differential. It was this “stuffing” that the British Range Rover had in the 70s. Thanks to such equipment, the domestic SUV could easily overcome fords, ravines and other off-road conditions. At that time, the new Soviet jeep had no analogues in terms of cross-country ability and comfort.
About the SUV body
It is worth saying that initially VAZ "Niva" 21213 was not all-metal. The first experimental modifications of the SUV in question had an open body, the roof of which was covered with a tarpaulin (such as a convertible off-road). However, in mass production included only models with a solid metal body, which we now see on the streets.
Equipment and comfort
At first glance, the VAZ "Niva" 21213 is the Volga analogue of the Ural UAZ 469th model. Yes, by driving performance and patency is almost like Siamese twins, but inside they are completely different. The front row of seats - with head restraints, the backrest is adjustable in length and angle of inclination, the rear row folds to increase luggage space. By order of the "Niva" was equipped with a washer and cleaner rear window, as well as an electric window heater. By today's standards, the equipment of the Volga SUV is almost ascetic, but in the 70s they did not even dream of such luxurious things.
Soul mates!
One of the most significant features of this car was that the bulk of the parts and assemblies were "thrown" from passenger models of the same VAZ (mainly "six"). So, on the basis of Soviet engineers, an engine, a rear axle and a gearbox were designed.
VAZ "Niva" 21213: specifications
Initially, the car was equipped with a 4-cylinder carbureted engine volume of 1.6 liters. Next came new modifications, as a result of which the line power plants replenished the 1.3-liter engine, but it was not particularly popular with motorists.
As for the gearbox, the Niva was equipped with a four-speed manual transmission with synchronizers in forward gear. A little later, the SUV began to be equipped with a more advanced transmission - 5 steps. Do not forget about the transfer case, which allowed the SUV to overcome any impassability. A two-stage "razdatka" with a center differential had a forced lock. consisted of cardan shafts of the rear and front axles, as well as an intermediate shaft.
The pendant also had its own technical features. The front one was independent, on transverse swing arms with hydraulic shock absorbers, springs and a stabilizer bar, which prevented the car from tipping over when cornering. Rear suspension- dependent, with coil springs, one transverse rod and four longitudinal ones. Like the front one, it was equipped with several hydraulic shock absorbers.
The first modernization of the domestic SUV
Strange as it may seem, the first modernized Niva model went into mass production only 16 years later. Moreover, practically nothing has changed in the technical part of the car - all parts and assemblies of the 1977 model! The exception was the new internal combustion engine, but more on that later.
The main changes affected only the external appearance of the Niva. New modification differs in a more elongated body and slightly modified rear brake lights. By the way, the trunk lid now opened only from the passenger compartment. The bumper remained metallic, but now it is painted in light gray. In general, the exterior of the car is not distinguished by particular sophistication and steepness. However, today's off-road tuning of the VAZ 21213 ("Niva"), which consists in installing snorkels, new disks and other units, can significantly modernize appearance car.
Inside, the changes were also minimal - the seats and the instrument panel became similar to the "Ladovsky" ones (from the VAZ 2108). What do the owners say? According to the reviews, the Niva 21213 became more comfortable after modernization, but the designers still could not avoid the old shortcomings (distortions of the back and constant noise inside).
And now for the technical part. Since the beginning of 1993, the upgraded version of the Niva has been equipped with a new gasoline engine with an increased working volume - up to 1.7 liters. For the first time on an SUV was applied contactless system ignition. The carburetor has also been changed. Improved brake system. The main gear of the checkpoint now has ratio 3.9. The muffler has also undergone minor changes. Now its body is not welded, as before, but rolled (like the "Lada" of the eighth model).
As practice shows, new improvements in internal combustion engine system and transmissions made it possible to significantly reduce fuel consumption on the VAZ Niva 21213 SUV. So, for a “hundred” a car spends about 13 liters in the city and up to 11 liters on the highway.
Export versions of the Niva had central fuel injection, were equipped with a non-switchable wheel drive with a center differential and a “razdatka” with a lowering row. At the request of the customer, the car could be equipped with French diesel engine from Peugeot with a working volume of 1.9 liters. But, unfortunately, these were only isolated cases.
Conclusion
Despite the fact that today there are many competitors for the Niva 2121, this SUV was, is and will be the best friend of hunters, fishermen and just off-road lovers. Due to the almost complete absence of electronics, the VAZ 2121 is perhaps the only jeep that can easily conquer any section of the road (with the exception of its Ural counterparts of the UAZ brand).
Four-wheel drive Niva (VAZ-2121) and its features
Any VAZ car is different from the Niva. And not only VAZ, but any other. The fact is that the Niva has a permanent all-wheel drive. This required the introduction of a transfer case into the transmission (the connection between the wheels and the engine). Because of this difference, there is a lot of confusion and many questions. Here are the answers to some of them.
1. No car without a differential. What it is? This mechanical device, which distributes traction from the engine to two wheels and provides them with the ability to spin at different speeds. The differential is vital for a car - when turning, the inner wheel travels less distance, and the outer one more. If there were no differential, then there would be a strong wear of the rubber, or when turning, one wheel would slip, spinning faster, the other would slow down, spinning slower. All this would provoke a skid. And axle loads would be very high.
In the Niva drive transmission of such differentials three. one in each axle (interaxle), so that the wheels have different speeds of rotation and one more, interaxle. located in the razdatka, to distribute the traction force between the axles. This differential allows the wheels of different axles to move at different speeds. In a normal straight-line movement without slipping, the traction force is divided in half by all differentials, and the same torque is supplied to all wheels. When a wheel slips through the differential, all the torque will go to the slipping wheel, and the traction force of the other wheels will decrease.
2. One of the main misconceptions about the Niva drive, it's a connectivity myth front wheel drive using the front handle. The fact is that Niva's "front end" is always on, this is a car with non-switchable all-wheel drive. And the mentioned handle changes the operation of the transfer case differential. When the handle is in the forward position, the differential works; in the backward position, it is locked. Why is it necessary? When the lock is off, the traction force between the axles is distributed equally, but if the center differential is locked, then the traction force is distributed in a completely different way. In this case, the traction force is transferred in the direction of greater resistance. If, for example, the rear wheel is slipping, then all the moment is spent on the slipping wheel. But if you turn on the interaxle lock, then the torque will begin to flow to the front axle, and the Niva will be able to overcome the obstacle. If at the same time it stalls and front wheel, then Niva will definitely not be able to leave. True, if you put a cross-axle differential lock, and there are such automatic lockable differentials, then Niva will be able to drive out on one wheel.
3. Another misconception related to the Niva drive: when switching the rear handle (large) we increase the engine power. This is not true. With this handle, you can change the gear ratio between the wheels and the engine for the transmission and change the traction force on the wheels. In the razdatka, in addition to the differential, there is a reduction gear, which is, as it were, a two-stage gearbox. The operation of this gearbox is controlled by this knob. When downshifting, we shift the operation of the gearbox in the direction of transmitting increased traction. the speed of movement is significantly reduced.
Therefore, before off-road, it is best to turn on a lower gear, which will increase traction. It is best to turn it on and off when the car is stationary.
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Permanent four-wheel drive. Is it good or bad? The transmission of the Niva is built in such a way that the torque from the engine is transmitted to the gearbox further to the transfer case in which the cross-axle differential is installed. which divides 50x50 torque between the front and rear axles. then the moment passes to the front and rear axles, the differentials of which also divide the torque between the 50x50 wheels. The uniform distribution of torque allows the all-wheel drive to work elastically. In the normal state, when one of the wheels is suspended, the torque on the suspended wheel will be transmitted 4 times faster due to two two differentials. That is, if the car is stuck and one of the least loaded wheels hangs out, it doesn’t matter the front or rear, it will rotate 4 times faster than the set speed. If we allow a rotation speed in first gear of 20 km / h, then the wheel will give out all 80 at the output. The transfer case has a rigid center differential lock that allows you to synchronously transmit torque to the front and rear axles, that is, turn on permanent hard all-wheel drive.
In this case, if there is a diagonal hanging, then the moment will be transmitted to the front and rear wheels, which have less grip with the soil. Accordingly, due to the differentials, the speed of rotation of these wheels will be doubled. The transfer case also has a reduction gear that enhances the torque transmitted to the axles and lowers the rotation speed.
Two short levers, the first closer to the panel is a center differential lock, the second is a downshift. So that's why I'm writing this. Niva has one property. on a slippery road with the differential not locked, it can suddenly turn around and lose control. Moreover, this happens instantly, even an experienced driver does not have time to respond to such a somersault. Why am I writing about this? There was a time when I worked on the Niva and drove mail around the area. Studied her habits inside and out. Of course, she has excellent cross-country ability, even with the differential not locked. When moving and accelerating, the torque is distributed along the floor along the axes. And only hanging one of the wheels can stop the movement. But the field has a long-travel suspension and the wheels almost always have traction with the ground, so there is a redistribution between the wheels evenly and the four-wheel drive works as it should.
Niva perfectly overcomes mud, sand, snowdrifts. And almost any rough terrain. But this article is not about the all-terrain capabilities of the car, but about the features of control in slippery times. Namely, a rolled winter road, ice, soil with low grip.
I have repeatedly found myself in a situation of a complete turn of the car on a slippery road, and if the car starts to turn around, this cannot be changed, it cannot be corrected by the steering wheel and an increase in gas. Especially if it happens at a sufficient speed. fraction of a second and the car drives backwards. The driver doesn't even have time to react. But this is if the differential is not locked. Although all-wheel drive is always on! Such a somersault is the norm. And now I want to substantiate this fact. What is it connected with?
For this, a small digression and comparison with other drives. Let's take rear-wheel drive as an example. On the example of classics 2101-2107
Rotation is given only for rear wheels. In slippery times, you have to work very carefully with the gas pedal, a small mistake causes a slip and at this moment, when maneuvering or hitting one of the wheels, the car can easily turn around. Moreover, the engine located in the front of the machine loads the front axle. The light back does not load the drive wheels, as a result, due to the lack of adhesion and the load on the drive axle, the wheels slip.
But drivers are adapting. Winter tires+ Ballast in the trunk of 50-60 kg and you can move. Skid at rear wheel drive occurs both during acceleration and when releasing gas. But drivers know these habits. Therefore, you can adapt and everyone drives like that.
Front-wheel drive on slippery roads is much more preferable than rear-wheel drive. The driving wheels are loaded with the engine + they also pull the car behind them into the turn. The only difference is that when entering a turn, do not release the gas, otherwise the rear can throw up and the car will turn around.
And so returning to the full drive to the Niva. When the center differential is off, the torque between the axles is divided in half. But the load on the front and rear axles are different. Pre loaded with engine box and transfer case. the back of the car is short on the rear axle, the load is less. Now imagine the situation of driving on a slippery road. The driver is completely confident, all-wheel drive is always on, what to fear. when driving and accelerating everything is fine. The car drives confidently on slippery roads and uphills. But the driver let off the gas in front of the obstacle and veered the steering wheel a little. The rear wheels, already less loaded, betray part of the load on the front wheels for gas discharge. The front wheels have good grip and still make friends. Resting, they slow down the movement of the car, but through the center differential they redistribute part of the load to the rear, as a result, the force directed to the unloaded rear wheels. I repeat the car is braked by the transmission! The engine speed drops and is a brake. To continue, through the good grip of the front loaded wheels, moment is transferred back to the transmission, the wheels make the engine spin while it slows them down. But it stands between the axle differential and it is not blocked, which means that part of the energy goes to the rear axle, and what wins is either the engine spins up or the rear wheels start to slide, and as soon as the loss of grip begins, the wheels will first slow down the rotation, then the torque will easily be transferred from the front axle to the rear, and the rear wheels will have a braking effect. While the front wheels will spin without locking up, the rear wheels will spin as well but at a slower speed within the error of the front differential. And in the end, what does that mean? Complete loss of traction rear axle with the road. It's just a sled. Therefore, with any maneuver, the car will instantly turn around and there is nothing to do. feature of this transmission. Therefore, on a slippery surface, it is imperative to block the center differential. Then the torque and braking moment is transmitted rigidly to two axles and the machine has good stability.